The search for alien life has tended to focus on looking for either signs of extraterrestrial technology or evidence of biological processes on other worlds. But new and ongoing research suggests that scientists should start considering signs of intelligence that are not necessarily technological, but which are sufficiently complex as to be evidence of a conscious mind at work.

Biosignatures are possible signs of biology on other planets, whereas technosignatures are clues to the presence of advanced technology that might be detectable across light-years. What, though, of everything that comes between these two extremes? How do we detect life that is more complex than simple microbes and which displays intelligence that is not highly technological?

This is where the field of noosemiotics comes in, says Julia DeMarines, an American astrobiologist who has been involved in both biosignature and technosignature research. "We want to figure out if we can detect signatures of intelligence that occur before the invention of radio communication," DeMarines told Space.com. "We're looking at the ways that mind can be imprinted on matter."

Noosemiotics is derived from the Ancient Greek concept of 'nous', which refers to the theory of mind. In the 1920s the Soviet biochemist Vladimir and the French Jesuit priest Pierre Teilhard de Chardin developed the idea of the noosphere as being the sphere of human reason or thought encapsulating the Earth.

More recently, Adam Frank, David Grinspoon and Sara Imari Walker applied the noosphere to SETI by considering the collective intelligence of all the beings on a planet acting as a kind of combined planetary scale intelligence.

Therefore, according to DeMarines, a noosignature would be a sign of a noosphere, of conscious minds at work.

"Bread doesn't just pop out of a molecular cloud"

Technology is, of course, a major imprint of mind on matter, and DeMarines acknowledges that just as technosignatures can be biosignatures since they can originate from biological entities, they can also be noosignatures — for instance, gases such as nitrogen released into the atmosphere by agricultural practices. But noosignatures can be something other than biosignatures and technosignatures, too.

Which is where DeMarines’ work comes in. She had been working for a company who were looking to apply the concept of Assembly Theory, which is a chemistry theory originated by Sara Walker and Glasgow-based chemist Lee Cronin, to online data and artificial intelligence to search for thresholds that denote complex signatures of intelligence.

Assembly Theory describes the minimum number of steps required to assemble something. In chemistry it is the steps taken to assemble, for example, important biomolecules, or to facilitate evolutionary processes. The number of steps taken is referred to as the Assembly Index. As part of her work on this, as a thought exercise, DeMarines was given the task of applying assembly theory to 'bread as a technosignature'.

"I know how that sounds," she laughed. "I get weird looks when I tell people about it!"

However, bread, like anything that is made by a conscious mind be it a stone tool or a radio telescope, is a signature of intelligence. At first DeMarines approached it as a proto-technosignature before realizing that it was more appropriate to describe it as a noosignature.

"Bread doesn't just pop out of a molecular cloud, it requires technology, it requires history, it requires intelligence," said DeMarines. "Say that you have samples of bread at different human and hominin archaeological sites throughout time, dating back 14,000 years – the bread would be a signature of intelligence changing over time as the type of bread, its ingredients and how it is made also change."

How it changes over time can be measured by Assembly Theory – the number of steps taken to get from early breads made from wild grain to modern sliced white bread produced from domesticated wheat is the Assembly Index. The task is to identify how many steps it takes to get past certain thresholds that indicate change, or rather developments, in intelligence, such as new technology for farming and germinating seeds, the construction of windmills or mass production.

As such, it fills part of the space between talking about a simple biosphere and searching for a technosphere, as do things ranging from stone tools to the development of written language and everything in between.

Non-technological intelligence

The trick, though, is detecting such signatures. Archaeological finds require being present on a planet, and digging up artifacts. Are there noosignatures that could be detected on other planets remotely from Earth? DeMarines isn't sure yet, and admits that at this stage she is thinking about it from the perspectives of metrics and thresholds rather than detectability.

If there are detectable noosignatures, they could also operate as a sign to anyone watching that there is intelligence on Earth, too. DeMarines highlights the example of gases released into the atmosphere by basic agriculture. Around three-quarters of all human-made nitrogen emissions were produced before industrialization, and agriculture was the source of that, ranging from fertilizers to animal waste to microbes in the soils used, all beginning many thousands of years ago.

For example, it took human civilization 4,000 years of bread-making before they domesticated wheat over 10,000 years ago. The release of excess nitrogen into the atmosphere disrupts the planet's nitrogen cycle, creating a disequilibrium.

While thousands of years is far too long a time for humans to detect such disequilibrium on exoplanets, alien observers may have been watching Earth for a lot longer than that. Common wisdom is that while biology on Earth has been detectable for billions of years through biosignatures, intelligence only became apparent in the past 100 years or so when we began beaming radio waves out into space.

However, if we are producing noosignatures that are detectable, such as disrupting the nitrogen cycle, then that means intelligence on Earth has been visible to the rest of the universe for much longer than we realized.

Then there's the conundrum of non-technological intelligent life in the universe. Often in the past intelligence has been equated to technology, but to solely rely on technology as a measure of intelligence misunderstands what intelligence is. Technological intelligence is one form of intelligence, but there are others.

Dolphins, for instance, are greatly intelligent creatures with sophisticated social interactions, but with the best will in the world dolphins will never have technology because they do not have the dexterity in their flippers to manipulate the environment around them to the necessary degree.

However, can they imprint their minds on their environment in other ways? It has previously been speculated that the universe is silent because technological intelligence is rare, but Dolphin-like intelligence could be abundant  — yet we'd never detect it. Now, thanks to noosemiotics, perhaps a way will be found to detect signs of such life. If that can happen, maybe we will quickly discover that we are not alone after all.

You can read about DeMarines work in a paper published on the open-source arXiv repository.

A rocky planet orbiting in the habitable zone of a sun-like star may look like a perfect place for life to thrive — but not if it's too small to hold onto its atmosphere.

So, we may wonder: How much smaller Earth could be and still have its delightfully breathable atmosphere? How small could an exoplanet be to sustain life as we know it?

With these questions in mind, University of California Riverside planetary scientist Michelle Hill and her colleagues recently simulated what happens to the atmospheres of different sizes of rocky worlds. The worlds tested were similar to Earth and orbited in the habitable zones around sun-like stars. It turns out for a world to maintain an atmosphere long enough for life to gain a foothold (a few billion years at minimum), it needs to be at least as big as Mars.

Narrowing down the search for life

The habitable zone — the area around a star where temperatures are right for liquid water to exist on a planet's surface — is prime real estate in the hunt for alien life. It's also a tough neighborhood for exoplanet atmospheres, because the closer a planet is to a star, the more ways in which radiation and stellar wind will try to strip away an atmosphere.

This is why Hill and her colleagues recently simulated how long it would take rocky, Earth-like planets of various sizes, in the habitable zone of a star like our sun, to lose their atmospheres. In other words, how much smaller could Earth, or a similar planet, be and still keep an atmosphere?

The answer turns out to be that an atmosphere-sustaining planet needs to be about 80% as wide as Earth, but could technically be as small as 60%. This offers astrobiologists a clue about which planets to focus on in the search for habitable worlds and signs of alien life.

"The plethora of exoplanets creates an interesting challenge in the search for potentially habitable planets," wrote Hill and her colleagues. "Of the many targets in the habitable zones of their star, which are the best candidates for follow-up observations with the aim of detecting biosignatures?" In other words, astrobiologists now have almost too many planets to choose from and not enough telescope time to search them all. So, it's time to narrow the search.

One way to do that is to figure out which planets are most likely to be habitable — and for life as we know it, that habitability means having an atmosphere.

Modeling atmospheres — and volcanoes

Hill and her colleagues' "Smaller Than Earth Habitability Model" simulates the fate of atmospheres around digital versions of Earth. Some of the simulated worlds are exactly like ours but smaller, with the same chemical makeup and the same proportions of core, mantle and crust. Others have slightly different amounts of carbon, larger or smaller cores, or different starting temperatures. The model traces what happens to these worlds over a few billion years, based on two things: how quickly stellar wind and radiation strip away gas from the planet's atmosphere and how quickly volcanoes pump out gas (mostly carbon dioxide) to replace it.

The model is how the team realized a scaled-down version of Earth needs to be at least 80% as wide as true Earth (0.8 Earth radii) to maintain an atmosphere in the long run. Smaller planets tend to lose gas faster than volcanic eruptions can replace it.

That's because smaller planets have less gravity and weaker magnetic fields with which to hold onto their thin envelopes of gas. They also don't usually release enough gas from within to make up for the loss. Their mantles — the churning layer of magma beneath the crust — tend to release less volcanic gas over time, and their upper layers cool and harden much faster. The latter process cuts off volcanic eruptions much earlier in a planet's lifespan.

Smaller planets clinging onto atmospheres

By changing some of Earth's parameters, the team managed to get planets as small as 0.6 Earth radii to maintain a stable atmosphere. Carbon was the key: planets with more carbon in their mantles tend to release more carbon dioxide gas in eruptions, and that turns out to be the biggest factor (other than size) in whether a planet keeps its atmosphere.

"Carbon dioxide is a heavy molecule," Hill and her colleagues wrote, "which can make it a difficult molecule to lose. We focus on a pure carbon dioxide atmosphere as a best-case scenario for atmospheric retention." Of course, that's only a best-case scenario for some relatively simple forms of life, so your astrobiological mileage may vary.

It took tons more carbon than Earth contains to make a significant difference to the fate of a planet's atmosphere — but because it's theoretically possible for a planet to form with that much carbon in its makeup, that's useful knowledge. Planets with relatively smaller cores, and therefore relatively thicker mantles, also had better luck on the atmospheric retention front. Starting with a larger supply of radioactive elements, which decay and release heat into the surrounding rock, helped keep the mantle molten and the volcanic gases churning skyward.

Starting with a cooler mantle also helps — which sounds surprising. You'd think a hotter mantle would be more likely to spew volcanic gases into the atmosphere. Yet, a cooler mantle takes longer to start erupting in earnest, which means the planet gets to hold onto its reservoir of gases until its star is older and more settled.

Newborn stars are prone to violent bursts of radiation and plasma, which would sweep away the volcanic gas as fast as it erupted. With a cooler mantle and later eruptions, the planet gets to keep more of the erupted gas.

A second chance for airless worlds

There's still hope of life for smaller worlds.

Even planets that lose their initial atmospheres entirely — instead of gradually replacing them with things like carbon dioxide and methane — might have a second chance to build a new atmosphere.

Hill and her colleagues suggest that one way for a planet to regain its lost atmosphere could be comet and asteroid impacts, which might deliver volatile elements like hydrogen, oxygen and carbon. These elements can combine to form all sorts of atmospheric gases.

Such impacts could be especially helpful if they happen later in the star system's life, like after the star is past its youthful phase of intense flares.

"While smaller planets face greater challenges in retaining atmospheres, our model suggests that they can develop atmospheres under the right conditions," wrote Hill and her colleagues, so, "even those that initially lose their atmospheres should not be immediately discounted as potentially habitable worlds."

What's next?

Future simulations using the Smaller Than Earth Habitability Model could study worlds around smaller, cooler stars called red dwarfs — stars like TRAPPIST-1, which is home to at least seven rocky planets, with three of them in the habitable zone. These stars make up about 75% of the stars in our galaxy, and their relatively dim light makes it easier for telescopes like the James Webb Space Telescope (JWST) to capture images of starlight filtering through the atmospheres of planets that pass between Earth and their host stars.

Hill and her colleagues also hope to explore what happens to atmospheres around tidally-locked planets, or planets where tidal forces keep the interior hot and seismically active, similar to Jupiter's moon Io.

The researchers published their work in June in The Planetary Science Journal.

Half a century after first putting hardware down on Mars, NASA is looking to explore the Red Planet's skies.

On July 20, 1976, the Viking 1 lander touched down in the western reaches of Chryse Planitia (the "Golden Plain"), a large circular landform that lies 22.5 degrees north of the Martian equator.

It was the first-ever Mars landing for NASA. Viking 1, along with its twin Viking 2, went on to conduct the first fully successful mission on the Red Planet's surface. (The Soviet Union's Mars 3 probe survived its touchdown attempt on Dec. 2, 1971 but died less than two minutes later.) And those missions have left a rich and intriguing legacy.

Viking 1 and Viking 2 — which touched down in a different Red Planet region on Sept. 3, 1976 — were sent to the surface to search for signs of life on Mars. (Each mission also featured an orbiter, which studied the planet from above.)

The landers did this using three different experiments, two of which returned negative results. But the third, called Labeled Release (LR), was different. LR observed a steady stream of carbon dioxide gas coming from dirt into which it had introduced nutrients — a possible sign of microbial metabolism.

Some scientists deemed the LR results a likely life detection. But most disagreed, ascribing them to abiotic reactions and stressing that, overall, the Viking data paint a picture of a dead planet.

That disagreement illustrates one of the main legacies of the Viking program: It showed researchers that hunting for extraterrestrial life is a complicated business, and they needed to learn more about Mars before attempting the search again on the Red Planet.

NASA didn't send a surface craft to Mars for another two decades, a hiatus caused in part by the Vikings' ambiguous results and high price tag, as well as a shifting of funds to the nascent space shuttle program.

The dry spell was broken in July 1997, when the agency's Pathfinder lander touched down in Chryse Planitia, about 530 miles (850 kilometers) from Viking 1. The main goals of Pathfinder's mission were to demonstrate a new "faster, better, cheaper" method of Mars exploration, prove out a new airbag-based landing system and get a mobile robot onto the red dirt.

Pathfinder achieved all of these objectives, notching the third by deploying a small rover named Sojourner. The little wheeled robot stumbled across rounded pebbles — strong evidence that they had been exposed to flowing water.

This discovery helped shape a new NASA Mars exploration strategy, one that aims to make an informed search for alien life after "following the water." Life as we know it depends on water, so the agency built rovers designed to hunt for signs of past liquid water and potentially habitable environments.

The twin golf-cart-sized rovers Spirit and Opportunity landed in 2004, and the car-sized Curiosity followed suit in August 2012. Then came Perseverance, which landed inside Mars' Jezero Crater in February 2021.

All of these wheeled explorers found evidence of past aqueous environments. Curiosity and Perseverance — with their more extensive and sophisticated scientific payloads — delved even deeper, discovering complex organic molecules that may have been produced by life as we know it.

The two latter rovers are continuing their work; both remain active on the Red Planet. (Pathfinder and Sojourner operated for about three months; Spirit was declared dead in 2010 and Opportunity fell victim to a Mars dust storm in 2018.)

Perseverance has collected a variety of Mars samples, which NASA wants to return to Earth for detailed study. As the Vikings' experience suggests, such a level of intense scrutiny may be necessary to make a definitive detection of life on Mars, if it indeed exists. (Getting those samples home is not a foregone conclusion, however; NASA's original plan was deemed too expensive, and it's now looking into a new return strategy.)

Perseverance also carried a little robotic companion, which heralded a new phase of Red Planet exploration — the Ingenuity helicopter.

Ingenuity was a technology demonstration, designed to show that rotorcraft could effectively ply the thin Red Planet skies. (Mars' atmosphere is just 1% as dense as that of Earth at sea level.)

The $80 million mission was a rousing success. The 4-pound (1.8 kilograms) Ingenuity was expected to make just five short hops on Mars but ended up flying 72 times over the course of nearly three years of activity. (Its first flight occurred on April 19, 2021, and its last was on Jan. 18, 2024.)

So NASA aimed higher, drawing up plans for future helicopter missions that could collect valuable scientific data. And such a mission is on course to launch in 2028, if all goes according to plan: Skyfall, which will send three Ingenuity-like choppers to Mars on a nuclear-powered rocket.

"Equipped with a suite of scientific instruments, these aerial scouts will map hidden ice deposits and analyze weather patterns," NASA officials wrote in a description of Skyfall. "The mission will also demonstrate how aerial vehicles can generate wide terrain and subsurface maps to identify safe and resource-rich destinations for future American astronauts venturing to Mars."

And Skyfall could be just another step toward even more ambitious aerial exploration on the Red Planet. NASA's Jet Propulsion Laboratory in Southern California, which built and operated Ingenuity, is looking into larger, more capable Mars helicopters that could do a wider variety of work on the Red Planet.

This is all part of Viking 1's legacy. That historic touchdown on Mars half a century ago lifted exploration up — all the way into the skies of another world.

In looking back and commemorating the 50th anniversary of the Viking missions to Mars, one is struck by the bold and audacious undertaking.

Twin spacecraft missions — each consisting of a lander and an orbiter — made their way to Mars and into the history books. The Viking 1 lander planted its legs on the terrain of Chryse Planitia 50 years ago today, on July 20, 1976, while its Viking 2 counterpart touched down at Utopia Planitia on Sept. 3 of that year.

Among their duties, the dual landers scooped up the first soil samples of Mars and deposited those precious collectibles into onboard, specialized equipment. Viking scientists had designed that gear to help answer an intriguing question: Is there life on Mars?

One of Viking's instruments was a GCMS, a combination of a gas chromatograph (GC) and a mass spectrometer (MS). A positive GCMS detection could confirm the possibility that organics needed for the origin of life as we know it were present.

After interpreting all the data and information gleaned from ingested Martian soil, most scientists at the time concluded that Viking relayed a "no life on Mars" result.

But is it possible that the two robots actually radioed back a very clear comeback: "Can you repeat the question?"

Different techniques

Ben Clark was a member of the Viking science team, and the instrument he designed made the first-ever measurements of the chemical composition of Mars soil. He is now a senior research scientist at the Space Science Institute in Boulder, Colorado.

"There were three life-detection experiments, each using different techniques to probe whether they could stimulate biological activity in the soil by adding various selected nutrients," Clark told Space.com. "Two were generally negative in their findings, but a third experiment had an expected strong response when it added nutrient."

Indeed, astrobiologist/inventor Gilbert Levin remained convinced that his Viking microbial detection instrument, called the Labeled Release experiment, did find living microorganisms in the soil of Mars. He held tight to that view until he passed in July 2021 at the age of 97.

Skeptical scientists

Clark recalled that many members of the scientific community were skeptical when geochemists pointed out that certain minerals can cause a similar response.

"Furthermore, when a second amount of nutrient was added, there was no additional response," Clark said. "Did the organisms die between experiments?"

Because of these responses, and especially because no organic molecules could be detected, most biologists concluded there was no life in the dirt that Viking tested. "However, there is also the question of whether the best nutrients were used in the Viking tests," Clark noted.

Microbiologists who study the small organisms that live in Earth soil, Clark added, know that some species are extremely adept at using sulfate as an energy source, by combining it with organics or with hydrogen gas.

"Unfortunately, none of the Viking life-detection experiments added hydrogen gas to their chambers," Clark said.

"Ironically, the instrument which searched for organics in the soil, the GCMS, used hydrogen gas in its analytical technique," he added. "Thus, there was a tank full of hydrogen gas located just centimeters away from the life-detection experiment package, but no connection between it and the GCMS where it was located."

True positive detections?

Even today, there are some scientists who question whether some of the life-detection experimental results were in fact true positive detections, according to Clark.

"Other scientists believe that it was not enough to simply test the loose soil, but that life in fact may be just centimeters below the surface in areas where there is still ice in the ground," he said.

Clark said that no other planet in our solar system so closely matches the early history of our own planet Earth.

"Recent discoveries by the rovers now roaming Mars have revealed some detections of organic molecules, and even some so-called 'reduction spots,' which are interpreted by some geologists as evidence of activity of biological organisms," he said.

Misunderstood results

Steven Benner is an astrobiochemist and director of the Foundation for Applied Molecular Evolution in Alachua, Florida. He is author of the soon-to-be-issued "Meet the Neighbors: Life on Mars and How to Find It" (Penguin Press, 2026).

Benner has long argued that the results from Viking were misunderstood. He contends that the Red Planet remains an easily reached destination to discover a possible independent origin of life and draws upon the Viking records to spotlight how the scientific process has failed in this regard to date.

Tied to Viking's 50th anniversary, "I decided to write a grumpy 'take no prisoners' book that dispenses with politeness and focuses on the facts," Benner told Space.com.

Misbegotten consensus

Benner said that his new book highlights two tales.

"Viking more likely than not found autotrophic microbial life on Mars, roughly 1,000 cells per gram — about what you might expect based on Earth analogs," said Benner.

The other story, he said, is that communities will defend a misbegotten "consensus" long after that consensus ceases to be defensible. They should not be beholden to a half century of mistakes, he emphasized.

The GCMS misinterpretation was 100% of the grounds for dismissing considerable life-positive data, according to Benner. So, he said, "we should then have gone back to the status quo ante, as Gil Levin did. But since 'consensus' in science is powerful, and Levin was polite, the community marginalized him."

Viking preservation

Rachel Tillman is the founder and executive director of the nonprofit Viking Mars Missions Education and Preservation Project.

Her late father, James Tillman, worked on Viking 1 and 2 and was a professor in the Department of Atmospheric Sciences at the University of Washington.

"There are a variety of reasons it's important to preserve Viking data," Tillman told Space.com. Archiving how and why things were done on Viking from an engineering standpoint is vital, she said, as is safeguarding the science data accumulated during the Viking program.

"Science is dynamic. Instruments and missions are finite in what they collect, so every data is part of a growing body of knowledge coming in pieces of a much larger puzzle. We can't complete the puzzle without all of the data," said Tillman. "So every facet of Mars science is a tiny piece of the puzzle. For that reason, we need to keep all the pieces."

This is true of every engineering success and failure, she added.

"Our organization has records on both. Because of that, we can help industry reduce costs by making the archives available on failed tests as much as successful ones," Tillman said.

It takes many, many missions to get close to answers we theorize on, she pointed out. "And then there is inspiration. By preserving the past — the who, what and how — we inspire youth and the public to support endeavors and even join the workforce," she concluded.

Contaminate and confuse

"The entire Viking mission — orbiters and landers — are one of the most important sets of data about the planet Mars," said Barry DiGregorio, an honorary research fellow for the Buckingham Center for Astrobiology in the United Kingdom. He is author of "Mars: The Living Planet" (Frog Books/1997).

"Indeed, the Viking biology data have become more important today than they were during the Viking mission," said DiGregorio. "Because Viking carried the very first suite of extant biology instruments to Mars, extreme care was given to the extensive heat sterilization protocols for the Viking landers."

Those protocols ensured that the Vikings did not carry large numbers of terrestrial microorganisms that might contaminate and confuse the actual soil sample results in its three onboard life-detection instruments, DiGregorio said.

Warning flag

However, DiGregorio is also waving a warning flag.

The recent discovery of never-before-detected extremophile microbes in spacecraft assembly clean rooms has made it important to take planetary protection protocols to a new level, said DiGregorio.

"Unfortunately, the search for extant life on Mars has been made much more difficult by unwittingly sending Earth's hardiest extremophile microorganisms there for the last 30 years," he said.

If Mars life is indeed spotted, extra effort will be required "to make sure it isn't earthly extremophile microbes we are detecting," DiGregorio added.

Both Viking landers ceased operating more than four decades ago. But they could still aid the Mars life search today, according to DiGregorio. Perhaps, he said, "comparing any new data found with archived Viking Lander biology data will be crucial in determining their interpretation."

Artificial intelligence could easily fall into the trap of identifying non-life as life on other worlds, claim two researchers from Michigan State University who have tested AI on simulated life in a computer program.

"We had previously seen that AI has a big Achilles heel when it is trying to classify things that are unlike the things in its training examples," Michigan's Christoph Adami told Space.com. "We call these 'out-of-distribution' samples and it is just incredibly easy to get AI to misclassify."

Adami is a computational biologist who uses computers to apply information theory to the study of evolution and biology. One of his leading tenets is that life can be defined by its ability to encode information and replicate it. To this end, he devised the Avida computer program in 1993. It runs digital organisms written as code that can replicate by copying themselves and competing for resources — in this case, CPU time — just like real life organisms. Although the use of digital life in evolutionary studies remains controversial, what it does provide Adami with is a huge dataset of simulated lifeforms that AI can be tested on.

Spending three months of computer analysis on a thousand parallel machines, Adami and his student Ankit Gupta asked AI to determine which programs in Avida had the properties of life, and which didn't. The life and non-life programs have very similar coding, so the difference is not obvious — and this might very well be the case on another planet where life could have differences in biology to Earth life.

Adami and Gupta started out with programs representing a random sequence of molecules and asked the AI to classify them. They then set about tweaking that sequence of molecules to try and fool the AI into thinking it was seeing life, one change at a time, each time checking whether there had been a change in how confident the AI was that it was life or non-life.

"Within about 15 changes or so we can get AI to be perfectly confident of a life classification when in fact not a single time when it was being 100% confident was it actually life," said Adami.

Furthermore, no matter the sequence they started with, the AI was constantly fooled.

Many in the scientific community stand by AI as an invaluable tool because it can process huge amounts of data and search for patterns in that data. Adami himself believes that AI has an important role to play, but as we see in everyday life, AI is prone to making things up and identifying patterns that don't exist.

This really comes down to what the AI has been trained on, said Adami. If you ask an AI about data it has been trained on, it usually provides a correct answer. For example, if you train AI to identify pictures of apples and then ask it to pick out the fruit from a dataset that also includes pictures of non-food items, it will answer correctly virtually all the time. However, if you replace the apple pictures with photos of bananas and ask it to identify the fruit, it will struggle and start to misidentify things.

That's because the bananas represent "out of distribution" data. The AI wasn't trained on bananas, which are a very different shape to apples, and therefore the AI doesn't know what to make of them.

Similarly, we don't know what alien microbes will look like, and they could be quite different to the terrestrial microbes that the AI has been trained on. In other words, the alien life would be out of distribution, and the AI would have no context for saying whether any particular collection of molecules is life or not.

"You need to know your training data, and if you know that your testing data is part of the same distribution as the training data, then you'll be fine," said Adami. "But you can't guarantee that with extraterrestrial life."

This could pose a problem for missions designed to look for life.

If a Mars rover goes to the red planet and cuts open a rock and directly sees something that looks like microbial life as we know it, then the answer will be clear-cut and can be tested using traditional methods. However, many attempts to detect life will probably not be so hands-on, relying on mass spectrometry data to identify molecules and processes related to life. This could range from attempts to detect life in the atmosphere of Venus, or in the ocean of Europa, or on exoplanets via the Habitable Worlds Observatory, which NASA aims to launch in the 2040s to directly image exoplanets in the habitable zone of stars.

"This means that if there were an AI on a mission looking at particular mass spectrometry samples, then there's a very great chance that while it has been trained on the ground on a number of biotic and abiotic samples, it could still return a positive verdict when it has absolutely nothing to do with life," says Adami.

Caleb Scharf of NASA Ames, who along with Carnegie Science's Michael Wong is spearheading a NASA-sponsored five-year, $5 million project to develop AI tools to help search for life on other planets, thinks that Adami and Gupta's findings are rather interesting. However, Scharf suggests that machine-learning algorithms can be honed to avoid falling into this trap by allowing for unknown categories rather than the limited binary options of life or not life available in the Avida experiment. 

"Gupta and Adami's study points astutely to a critical challenge in life detection that might undermine the hoped-for gains from AI and machine learning: what do we do with the unknown unknowns?" Scharf told Space.com. "We think the answer may lie in allowing algorithms to notice situations where things look askew, andthere are methods from data science to tackle this very probllem, which we're actively exploring."

The next step, said Adami, is to move out of the digital world and run the same test with real-world data.

Adami and Gupta will be presenting their findings in August at the 2026 Conference on Artificial Life, which is being held in Waterloo, Canada.

Harvard astrophysicist Avi Loeb has been appointed as the head of a new White House group to study unidentified anomalous phenomena or UAP, a new catch-all term for UFOs that might appear not just in the air but also in space or underwater. Loeb says the group is focused on evidence, instrumentation, data analysis and collection standards.

The move follows recent Trump administration initiatives to bring more transparency to the topic of UFOs, or UAP. The UAP Science Advisory Council, Loeb explains, was established by the White House, the Pentagon's All-Domain Anomaly Resolution Office (AARO), the Office of the Director of National Intelligence (ODNI), the Federal Bureau of Investigation, and other members of the Intelligence Community.

Loeb co-founded and leads the Galileo Project, designed to bring the search for extraterrestrial technological signatures of extraterrestrial technological civilizations "from accidental or anecdotal observations and legends to the mainstream of transparent, validated and systematic scientific research."

As chair of the just-formed UAP Science Advisory Council, Loeb has built a team of researchers that he describes as "an amazing A-team of exceptional scientists and experts."

Members of the group come from a wide range of disciplines from data science and instrumentation to biology, oceanography, anthropology and psychology.

The council's stated purpose is to help government agencies study the nature of UAP through rigorous scientific methods, with an emphasis on collecting and analyzing higher-quality data rather than relitigating older material that cannot be independently verified.

Meet the team

But first things first.

What is the current membership makeup of Loeb's Council? It's quite a mix of talent to undertake a new look at UAP:

• Liberty Capito is a professor of practice in data science at the Olin Business School at the Washington University in St. Louis.
• Carol Cleland is a professor in the Department of Philosophy at the University of Colorado Boulder.
• Richard Cloete is a computer scientist at Harvard University and a member of Loeb's Galileo Project.
• Omer Eldadi is in the department of psychology at Reichman University, Herzliya, Israel.
• Tim Gallaudet is a retired Navy admiral and oceanographer.
• Robin Hanson is an associate professor of economics at George Mason University statistics and economics.
• Ross Howard is producer of John Michael Godier's Event Horizon podcast that explores the technosignatures of alien technology. He is also with the Sol Foundation aimed at addressing the UAP issue and preparing society for its social implications.
• Kevin Knuth is a professor of physics at the University at Albany.
• Ravi Kopparapu is a NASA Goddard Space Flight Center expert having research interests in extrasolar planet habitability, atmosphere modeling and characterization.
• Ben Lamm is the co-founder and CEO Of Colossal Biosciences, the world's first de-extinction company.
• Jacob Haqq Misra, of Blue Marble Space, is a meteorology and astrobiology specialist.
• Devesh Nandal is a Swiss National Science Foundation postdoctoral fellow at the Center for Astrophysics at Harvard and Smithsonian.
• Garry Nolan is professor in the Department of Pathology at Stanford University School of Medicine and is executive director of the board of the Sol Foundation.
• Michael Shermer is the founding publisher of Skeptic magazine and an educator on critical thinking.
• Peter Skafish is a sociocultural anthropologist and secretary of the Sol Foundation.
• Matthew Szydagis is an associate professor in the Department of Physics at the University at Albany.
• Jennice Vilhauer is a clinical psychologist with expertise in quantitative psychology and the psychological dimensions of potential disclosure.

Data-driven, physics-based

Space.com reached out to several of the UAP Council members to get their personal views on this new study approach.

"I expect the council and myself to follow methods and techniques deeply rooted in the scientific principles," said Devesh Nandal.

"The UAP Science council in particular is focused on a data-driven and physics-based approach on the topic of UAP," said Nandal. "We approach this topic with the same rigor we apply in our respective scientific fields and we hope to provide an unbiased analysis on this topic."

Nandal said his role is to help with quantitative data analysis and apply his expertise in astrophysics to help the council decipher the origin of UAPs.

"My first and foremost passion is in stellar astrophysics where I study the life and death of massive and supermassive stars," Nandal said. "I also find the anomalous nature of UAP sightings to be quite intriguing, and whether these events are of terrestrial or extraterrestrial origin, I am excited to apply my understanding of physics to decipher their true nature," he said.

If such events can be explained using known principles, "that's excellent," Nandal advised, as this gives him a chance to test the laws of physics to explain a phenomenon that is captivating fellow humans.

"If such events are beyond our current understanding, I see this as a brilliant opportunity to learn all that I can about the Universe and share my findings with everyone," Nandal concluded.

Public trust in science

Council member Liberty Capito said she's honored to be a part of the study group.

"Avi is one of the most brilliant scientists of our time and what he has put together, is what I believe to be a blueprint for re-establishing the public's trust in science by having people with vastly different views, beliefs and science on it," Capito said.

From Council member, Robin Hanson: "It's an honor to be invited, and it's a great cause. I worried at first if we could find much useful to do, but it seems that we do have some promising ideas."

Another member of the UAP Council is Carol Cleland, a professor in the Department of Philosophy at the University of Colorado Boulder. She is a Search for Extraterrestrial Intelligence Institute Affiliate and a member of CU Boulder's Center for Astrobiology.

"I anticipate having a council of outside experts will pressure the government to be more open about releasing information and allowing members of the council to interview UAP witnesses," Cleland told Space.com.

Potential positive

Identifying the unidentified deserves a high priority within the U.S. government and the scientific community, explains Loeb.

Nevertheless, for organizations that also continue to diligently sort out what's behind unidentified flying objects (UFOs) in the past and the current UAP tag line, they are taking a cautiously optimistic attitude.

"The involvement of serious, independent scientists is a potential positive development, and the government requires that for any thorough and credible investigation of UAP," said Mark Rodeghier, president and scientific director of the J. Allen Hynek Center for UFO Studies since 1986.

The key issue is not the credentials of the people involved, Rodeghier said, but the structure they are working within.

"If the Council lacks a clear mandate, access to relevant data, a collaborative relationship with those actually grappling with the UAP problem in the government, and then a path for public reporting, its practical value may be quite limited," Rodeghier told Space.com.

Wait and see

Robert Powell, an executive board member of the Scientific Coalition for UAP Studies, said he's adopting a "wait and see" attitude regarding the UAP Council at this point in time.

"Since the UAP Council seems to have the ear of some in Congress," Powell told Space.com, "I hope that they will spend some of their time advocating that Congress appropriate funding specific to the study of UAP through the National Science Foundation."

In SCU board meetings, Powell added, they are a strong proponent of making funding available to the scientific community and academia.

"We never know from where a breakthrough may occur in the study of UAP," Powell said, "and the more scientists involved from all areas of research, the better."

Is there life on Mars … in clay? Scientists think that the minerals in clay could be the key to finding signs of ancient life on the Red Planet.

The European Space Agency is still working toward launching its ExoMars Rosalind Franklin rover to Mars to search for signs of life. And, according to a statement from the space agency, the rover is now aiming to land at Oxia Planum, a depression on the Martian surface where it's thought that water was once plentiful. There, scientists think that they might find major clues in the hunt for life in the basin's clay, according to a new paper.

"We will use the instruments on board to ground truth the discoveries made from orbit, learn about the ancient environment in which they formed, and if they preserve any evidence of Martian life. Warmth and nutrients on an early martian seabed could have provided habitats for early life," ExoMars deputy project scientist Elliot Sefton-Nash added in the statement.

Scientists have spent years searching for signs that life once existed on Mars. It's thought that water on Mars evaporated around three billion years ago, but before then the planet likely had a more substantial atmosphere and water flowing in rivers and into lakes all across its surface. Because of the planet's history, many scientists think that it's most likely that at some point in the ancient past, the planet must have supported life. While this has yet to be confirmed, last year scientists found what is currently thought of as the strongest possible biosignature, or physical evidence of life, on Mars.

In a new study, researchers have found extensive clay deposits at Rosalind Franklin's proposed landing site. They found this clay to reach roughly 186 miles (300 kilometers) outward from Oxia Planum, stretching as far as a Martian valley called Mawrth Vallis. To spot the clay, they first studied the planet from orbit.

Researchers used the OMEGA instrument on ESA's Mars Express orbiter and NASA's Mars Reconnaissance Orbiter to explore the minerals and rock layers on Mars between Oxia Planum and Mawrth Vallid, finding mineral layers at both sites as well as markers showing changes in water chemistry over time. These observations add to other studies pointing to water on ancient Mars.

With ESA's upcoming rover, some scientists think that the clues to life on Mars could be hiding in this clay in the Oxia Planum region.

"By landing at Oxia Planum, we’ll uncover a large-scale process that shaped ancient clays across Mars," lead author Inés Torres Auré of the University of Lyon in France said in the statement.

Scientists think that it's possible that the area of Oxia Planum could have once been home to a body of water as big as an ocean or the region could possibly have experienced incredible flooding some four billion years ago, according to the statement.

"Because the area is so large, we are not talking about a localised occurrence, but rather a regional or global process that would have required immense amounts of water. We are targeting the oldest deposits in the sequence, which makes the potential implications for the geology and early climate of Mars very relevant for the Rosalind Franklin mission in its search for life," ExoMars project scientist Jorge Vago explained in the statement.

While we have never confirmed life off-Earth and it could be different from the life we know, as far as life on Earth is concerned, water is a necessary ingredient.

ESA's Rosalind Franklin rover is projected to launch to the Red Planet in 2028. The rover will be part of ESA's ExoMars program alongside the agency's Trace Gas Orbiter which is already traveling around Mars. Rosalind Franklin will have a drill, allowing it to explore below the planet's surface as the pair work together from orbit and on the Martian surface to hunt for signs of ancient life.

This work was described in a study published in the journal Science Direct.

The United States has taken some significant steps into the final frontier during its first 250 years.

The nation has put people on the moon, helped build and operate a long-running space station in low Earth orbit (LEO) and sent fleets of robotic explorers to many corners of the solar system — and even beyond it, into interstellar space.

All of this work has been done relatively recently, as the space age didn't dawn until 1957; when the U.S. was born on July 4, 1776, humanity was still seven years away from even balloon-borne flight. Where might we be another 250 years from now, on the nation's 500th birthday, should it be fortunate enough to live that long? Trying to see that far into the future is so difficult as to be a fool's errand, but it's fun. So let's have a brief and far from exhaustive crack.

A vibrant in-space economy

The United States and other space powers have already established an off-Earth economy — one based on the activities of communications satellites. Companies like Vantor and Planet sell imagery to a variety of customers, for example, while others like SpaceX (via its subsidiary Starlink) and Viasat provide internet service from above.

That nascent industry will doubtless expand greatly over the next 250 years, and we're already seeing some of the directions it may go. For instance, space tourism has gotten off the ground; wealthy people can book trips to suborbital space, and the super-rich can fly all the way to Earth orbit, as the experience of NASA chief Jared Isaacman shows. (Isaacman, a tech billionaire, has funded and commanded two missions around our planet using SpaceX hardware.)

We've also seen the dawn of in-space manufacturing, with companies such as Made In Space making stuff off Earth and bringing it down for analysis (and eventually, if all goes to plan, sale). This is a field that could really explode over the coming years and decades, according to Dava Newman, director of the Human Systems Lab at the Massachusetts Institute of Technology, who served as deputy administrator of NASA from 2015 to 2017.

"If you give me a nice big time horizon to look at, I've actually always thought it would be a pharmaceutical breakthrough — manufacturing, more medical-related," Newman told Space.com.

That's because the microgravity environment is great for growing flawless crystals, potentially enabling a newly efficient and effective production line for a wide range of pharmaceuticals and other high-value goods. The California company Varda Space recently demonstrated this potential, successfully crystallizing a stable form of the HIV drug ritonavir in one of its orbital "minifactories" and bringing the drug safely down to Earth.

Asteroid mining, too

There are other potential drivers of a booming off-Earth economy as well. Futurist, astrophysicist and sci-fi author David Brin pointed to asteroid mining, which several American companies, including AstroForge and TransAstra, are investigating seriously already.

"That's where the riches are," Brin told Space.com.

Those riches come in several forms. For starters, many asteroids are thought to harbor considerable amounts of water, which humanity could leverage for life support and split into oxygen and hydrogen, key components of rocket fuel. Space-rock mining could therefore enable the operation of off-Earth propellant depots, which would allow voyaging spacecraft to top off their tanks on the go and explore the solar system more deeply and ambitiously.

Then there are the metals — industrial-grade stuff like iron and nickel, which could feed the off-Earth manufacturing industry, and precious species such as platinum. So there are huge economic opportunities for us in the asteroid belt, according to Brin.

“The question is, will we be able to leverage asteroidal resources to get a takeoff industry out there?" he said. "And will we remain friends with the robots out there that are doing all of the work?”

That latter question is a serious one, for robotics and artificial intelligence will advance a great deal over the next 250 years. Indeed, humanity will likely merge with robots in meaningful and ethically confounding ways, according to Brin.

"There will be fuzzy boundaries between us and the robots," he said. Our species, Brin added, may eventually "range from residual totally organic types through cyborgs and multilinked clusters all the way to robots who either think of themselves as human citizens, or at least know that it's in their best interest to fool us into thinking they think that."

Living off Earth

There's no guarantee that the U.S. will be able to exploit the plentiful resources of the asteroid belt by 2276. For instance, Brin stressed that the nation, and the world at large, are in danger of falling into a sort of "lobotomized feudalism," which could derail most of our spaceflight hopes and dreams.

If we can avoid that trap, however, Brin thinks that asteroid mining could fuel our expansion into the solar system over the coming decades.

"I have no doubt that, if we restore a rational, scientific civilization, there will be city lights on the moon," Brin said. "I am hoping there will be city lights on the asteroids."

Newman has a different outlook. For starters, she's opposed to the idea of transplanting human civilization on a large scale to pristine worlds.

"I'm not a fan, of course, of colonization," she said. "We should never do that. History should teach us something."

She also doesn't see a business case that would drive companies to spend large amounts of money on moon and Mars activities, which could be prerequisites for the establishment of large human settlements there. And she's skeptical that many people would want to pack up their lives and move to Mars or the moon permanently.

"There's a reason Antarctica is not populated," Newman said. "I love it, I can't get enough of it, but that's pretty crazy. Most people don't want to be in a very isolated, confined environment."

Mars settlement, she added, "doesn't make any sense. It's not Option B. We have to take care of this planet."

Newman still thinks that we should (and will) explore the moon and Mars in the not-too-distant future. But she envisions a much smaller-scale effort that's driven by ambitious science goals — a committed search for signs of life on Mars, for example. This effort will likely start with small outposts on the moon, which will serve as stepping stones for similar activities on the Red Planet.

This vision is not exactly far-fetched; it's the approach that NASA is currently taking with its Artemis program. The agency plans to build an astronaut outpost near the lunar south pole over the next decade or so, then use the information gained to send astronauts to Mars in the late 2030s or 2040s.

A moon or Mars base would be a huge breakthrough, of course, but it wouldn't be our species' first toehold in the final frontier. We've had one since November 2000, when the International Space Station — a partnership involving the space agencies of the U.S., Russia, Europe, Canada and Japan — began hosting astronauts on a continuous basis. The orbiting lab has been occupied by rotating crews ever since.

Are we alone?

The U.S., and the world at large, will doubtless make great strides in space science over the coming years as well. Indeed, Newman thinks we will answer perhaps the biggest question of all — and doing so won't take anywhere close to 250 years.

"I think definitely we will have found [alien] life," she said. "I think we might find the evidence of life — and it's probably going to be past life — in the coming decade."

Her optimism is based on a number of data points. One is the example of our own planet: Life sprang up here about four billion years ago, not long after Earth had cooled enough to support oceans on its surface. That suggests it doesn't take a miracle for a world to go from habitable to inhabited.

And our solar system hosts multiple worlds that could be habitable. Multiple moons in the outer solar system — Saturn's Enceladus and Jupiter's Europa, for example — host big liquid-water oceans beneath their icy shells. Titan, Saturn's biggest satellite, hosts hydrocarbon lakes and streams on its surface and likely has a buried water ocean as well, raising the possibility that it could support two entirely different types of life.

Then there's Mars. Scientists know that the Red Planet had lots of surface water in the distant past, around four billion years ago. They see evidence of lakes and streams in many Martian locales, some of which have been explored by rovers like Curiosity and Perseverance. And both of those NASA robots have discovered complex organics, the carbon-containing building blocks of life as we know it. Such molecules are not convincing evidence of life, but they're suggestive and intriguing. And humanity aims to follow up on such finds — possibly by astronauts working out of a research base. Mars is therefore the place where we'll likely make the big discovery, Newman said.

Brin was similarly optimistic, predicting that we'll find evidence of alien life in the next 20 years "if we reclaim our potential as an exploratory culture." Mars could be the place it's found, but he thinks the chances are perhaps even greater on Titan and "ice roof" worlds like Europa and Enceladus.

"I would bet 3 to 1 odds we'll find life under ice roofs," Brin said.

If multiple icy moons have life, and we can confirm that each one represents an independent origin, that would tell us something very profound: That life is exceedingly common across the universe.

"It would mean that every star you can see, except perhaps the blue supergiants, has life," Brin said.

The search for intelligent life

The first alien lifeforms we find will probably be microbes, because most life across the universe is likely microbial. That's an inference we can take from Earth, the only inhabited world we know of: Life here remained single-celled for about three billion years, suggesting it's tough to make the leap to more complex organisms.

Becoming a technological civilization is another big leap, one that humanity made just a few centuries ago. But given the vastness of the universe, in both time and space, life has probably made this leap in other places as well, and Brin is bullish on our chances of crossing paths with such aliens — provided we make the right choices in the near future.

“If we restore a dynamic and scientific civilization, we might get some answers to that within 20 to 30 years," he said.

Those answers might come close to home, in the form of long-hidden "lurker" probes sent to our solar system to monitor us on the sly. Or we might pull a world-changing SETI (search for extraterrestrial intelligence) signal from the sky, one that could not have come from a natural, astrophysical source.

Given how young humans are technologically, however — we started launching things to space less than 70 years ago, after all — we probably won't get the drop on advanced aliens, if they're out there.

"Is it likely that intelligent life will actually find us before we find them? I think that's a pretty good probability," said Newman, who sits on the SETI Institute's board of directors.

And we have a chance to mature greatly as a spacefaring civilization over the next 250 years, Brin said. If everything goes well — we don't fall back into feudalism, for example, and we fully exploit the resources of the asteroid belt — the U.S., and humanity overall, we will likely be able to explore other star systems in a meaningful way. He cited laser sailing as a promising propulsion method, one that could send robots — and perhaps cybernetic versions of ourselves — very far afield on reasonable timescales.

"If we make a dynamic, enlightenment civilization, then it's 100% that we'll send somebody out there," Brin said.

A new planetary habitability model could make the search for aliens more efficient by quickly identifying rocky worlds unlikely to sustain the atmospheres needed for life as we know it.

The software, called the Smaller Than Earth Habitability Model (STEHM), allows astronomers to screen exoplanets before committing valuable telescope time to detailed observations. Developed by researchers at Stanford University, the model assesses whether a rocky planet can build and retain an atmosphere over billions of years — a prerequisite for life as we know it, according to a statement from the university.

Astronomers searching for life beyond Earth face a daunting challenge: thousands of exoplanets have already been discovered, and billions more are thought to exist throughout the Milky Way — roughly one for every star in the galaxy. As powerful new telescopes come online, researchers increasingly need ways to identify which worlds are worth closer study.

"The only way that we're going to ever find out if there are signatures of life out there is by observing the atmosphere of these planets," Michelle Hill, lead author of the study who developed STEHM, said in the statement.

Traditionally, scientists have focused on whether a planet lies within its star's habitable zone, the region where temperatures may allow liquid water to exist on the surface. But location alone does not guarantee habitability. A planet without a substantial atmosphere may be unable to maintain stable temperatures, shield itself from radiation or support surface water, the researchers said.

STEHM adds a second layer to this assessment by estimating whether small rocky planets can generate and retain atmospheres over geologic timescales. The model links a planet's size to its ability to hold onto atmospheric gases, helping identify a lower size threshold for potentially habitable worlds.

To build STEHM, Hill used the ExoPlex planetary simulation code to model six rocky worlds ranging from half Earth's size to Earth-size, testing how planetary structure, volcanic activity, internal heat and stellar radiation affect atmospheric survival. The model was validated using Venus and Mars, correctly reproducing Venus's thick carbon dioxide atmosphere and Mars's long-term atmospheric loss.

The results suggest that rocky planets at least 80% the size of Earth can retain atmospheres for 10 billion years or more when orbiting within habitable zones around sun-like stars. Smaller planets generally lose their atmospheres more quickly, though worlds around 70% of Earth's size may still be habitable under favorable conditions. Atmospheric longevity also depends strongly on initial carbon content and heat-producing elements that drive volcanic activity, allowing STEHM to serve as a size-based filter for identifying the most promising habitable worlds.

"Maybe there's life on other planets under the ground, but we are never going to be able to see it because we can't send something to those exoplanets," Hill said in the statement. "The best chance we've got is looking for signs of life by analyzing atmospheres from afar."

By narrowing the field of candidates, STEHM could help astronomers focus on the most promising planets for life while avoiding wasting resources on unlikely targets. The approach may be especially useful as next-generation missions, such as the European Space Agency's PLATO space telescope, expand the catalog of rocky exoplanets around nearby stars. Researchers hope the model will help prioritize which of these planets merit follow-up observations.

STEHM not only addresses where life beyond Earth could occur, but when it might, by modeling whether exoplanets can actually hold onto atmospheres over geologic timescales — a key prerequisite for life to take hold in the first place.

"Maybe the answer to why we haven't found any life yet is that we're so early in the grand scheme of what has been created through the lives and deaths of stars," Hill said in the statement. "Maybe we're one of the first."

Their findings were published June 4 in the Planetary Science Journal.

Earth got some of the key ingredients for life from asteroids in the inner solar system – with a little help from the solar system's largest planet, Jupiter, according to a recent study.

To figure out why we’re all here, and whether anyone else might be out there in the universe, scientists have to start with a more basic question: how did Earth get its supply of the chemicals that make up living cells?

According to Rice University planetary scientist Rajdeep Dasgupta and his colleagues, Earth’s stockpile of phosphorus and nitrogen, two chemical elements essential to life, came mostly from chunks of rock that formed in the inner solar system. And that process might not have happened without Jupiter looming just outside the asteroid belt.

"For our own solar system, Jupiter's presence and growth history indeed seem to have played a critical role in determining the distribution of the basic chemical ingredients necessary for habitable worlds," said Dasgupta in a NASA press release. "It remains an open question whether a life-essential elements budget similar to Earth's can be estimated without a Jupiter-like planet in the population."

Jupiter scores an assist

Dasgupta and his colleagues combined lab experiments and computer simulations to map the proportions of nitrogen and phosphorus, two chemical elements essential to life, in the early solar system. Life as we know it is literally built on these two elements; you can't build amino acids without nitrogen, and you can’t build DNA or RNA without phosphorus.

Other elements are also essential: carbon, hydrogen, oxygen, and sulfur, but how Earth got its phosphorus, in particular, has gotten less attention from researchers so far.

When scientists are investigating how Earth might have received the ingredients for life, one big clue is the ratio of each element to the others. Those proportions can form sort of a chemical fingerprint pointing back to the elements’ original source. In this case, looking at the ratio of phosphorus to nitrogen in present-day Earth’s rocky bulk could shed some light on where Earth’s phosphorus came from.

In the lab, the researchers simulated how different elements sort into layers as a newly formed asteroid cools, causing molten rock to crystallize. They also used computer simulations to model how different groups of planetesimals, clumps of metal and rock that coalesced out of the swirling disk of dust around the newborn sun, became the seeds of potential planets, formed and moved around the early solar system – moving phosphorus and nitrogen with them.

It turns out that present-day Earth contains phosphorus and nitrogen in about the same proportions as rocky planetesimals that formed in the inner solar system, the area between Jupiter and the Sun, around 4.3 to 4.2 million years ago.

Dasgupta and his colleagues’ models suggest that these chunks of rock, part of our solar system’s second generation of planetesimals, probably brought their shares of phosphorus and nitrogen to Earth as our planet was still forming. In a lot of cases, Earth’s gravity probably captured these objects and pulled them in, adding them to its growing bulk. Others got flung toward the accreting planet by collisions or close encounters with other objects, and Jupiter played a key role in that process.

Jupiter formed before Earth, and its tremendous gravitational influence shaped how material flowed through the disk of gas and dust that orbited the young sun.

Before Jupiter loomed onto the scene, material in the disk tended to flow outward, carrying its stores of phosphorus and nitrogen with them. However, Jupiter's hulking presence blocked most of that flow, keeping more of that rock, dust, and gas trapped in the inner solar system.

As the second generation of planetesimals was forged in the inner solar system around 4.3 to 4.2 million years ago, with Jupiter presiding, they formed with a higher ratio of phosphorus to nitrogen than their older siblings out beyond Jupiter's orbit.

Thus, the solar system's most massive world played a key role in distributing elements throughout the solar system, including those vital to life that were later delivered to Earth by asteroids that impacted our planet in its infancy.

Dasgupta and his colleagues published their work in the journal Science Advances.

NASA's Habitable Worlds Observatory is the agency's next flagship space telescope, designed to do something no previous instrument has managed: directly image Earth-like planets around nearby stars and analyze the light reflecting off their atmospheres for signs of life.

The mission is still years from launch. But the design choices being made right now will determine what it can actually detect. A new paper posted to the arXiv preprint server tackles one of the most consequential of those choices: spectral resolution.

The authors of the study ran a careful analysis of how finely the Habitable Worlds Observatory (HWO) would need to slice up the light from a distant Earth to confidently spot biosignatures in its atmosphere. The question matters more than you might think.

Spectral resolution is how well a telescope can distinguish between adjacent colors of light. Higher resolution means a more detailed atmospheric fingerprint, but it also means longer exposure times, more detector noise, and trickier engineering. Push too high and you blow the mission's observing schedule. Push too low and you can't tell the difference between an inhabited planet and a barren one.

To estimate what type of spectral resolution would be needed to detect biological signatures on our planet in its infancy, the team modeled what HWO would see when staring at versions of Earth through geological time.

Earth's atmosphere has changed dramatically over its history. The Archean Earth, before plants and cyanobacteria got going, had almost no oxygen. The Proterozoic Earth had some, but not much. The Phanerozoic Earth, the one we know, hit roughly 20 percent oxygen once complex life took hold. Each leaves a different spectral signature, and HWO will need to recognize all three.

The headline numbers are surprisingly modest. To detect molecular oxygen, the gold-standard biosignature on a planet like our own, HWO needs a visible-light resolving power of about 140. Ozone shows up at a much lower resolving power of around 7 in the ultraviolet. Those numbers are well within what current optical designs can deliver.

The infrared is harder. Carbon dioxide and carbon monoxide have spectral features that overlap, and if HWO can't tell them apart, it could mistake a volcanically active dead planet for a living one. The team found that a near-infrared resolving power of at least 40 is the minimum needed to break that degeneracy. To characterize an atmosphere through Earth's entire geological history, they recommend a nominal infrared resolving power of about 70.

How did they arrive at those numbers? They generated synthetic HWO observations across resolving powers from 20 to 5,000, then ran each simulated spectrum through retrieval algorithms to see what could actually be inferred about the underlying atmosphere. They factored in detector noise, exposure time, and anti-biosignatures (atmospheric features that would argue against the presence of life).

There are real engineering limits in play. The dark current of HWO's detectors, the tiny background hum of electrons that any detector generates even with no light hitting it, sets a hard floor on what fine resolution can buy you. Pushing oxygen detection significantly further than the baseline would require reducing that dark current by roughly a factor of ten. And pushing to higher resolution for oxygen would roughly double the exposure time needed for water vapor.

The authors are careful about the limits of their analysis. Their absolute exposure times could be off by around 20 percent. And the more philosophical caveat is the one that has always shadowed this work: even a confident detection of oxygen, ozone, methane, and water in an exoplanet atmosphere is not the same as a confident detection of life.

The universe has non-biological ways to make any one of those gases. HWO's job isn't to declare victory on its own: it's to find the candidates worth following up on.

What this paper provides is a clear, quantitative target for the engineers building the instrument. A resolving power of 140 in the visible, 7 in the ultraviolet, and 70 in the near-infrared, with low enough dark current to make oxygen detection routine. That is the spec sheet for a telescope that could, in principle, find signs of life on another world.

Now we just have to build it.

The International Academy of Astronautics (IAA) has ratified protocols advising what an astronomer should do if they discover evidence for extraterrestrial intelligence in our modern global world of social media, AI deep fakes and misinformation.

Referred to as the "Declaration of Principles Concerning the Conduct of the Search for Extraterrestrial Intelligence (SETI)," the post-detection protocols cover everything from handling the evidence, and how the discovery should be communicated to the world to the challenge of what comes after the discovery. In a world where an AI hoax could easily be promulgated across social media, or in which conspiracy theorists would likely attack a real discovery, the protocols are intended to encourage best practice and safeguard astronomers when the media spotlight falls on them.

And despite how this summer's Steven Spielberg blockbuster, "Disclosure Day," presents the discovery of extraterrestrial life as a grand conspiracy to be disclosed, transparency is a top priority in the Declaration of Principles.

"There is no secret file on aliens," Michael Garrett, who is the Sir Bernard Lovell Chair of Astrophysics at the University of Manchester, told Space.com.

Garrett also chairs the IAA's Permanent SETI Committee and is the lead author of the updated Declaration, along with anthropologist Kathryn Denning of York University in Toronto, Arizona law expert Leslie Tennen and science-communication expert Carol Oliver from the University of New South Wales in Sydney.

"If we ever find a credible signal, the public will know; it won’t be hidden away in some government vault," continued Garrett. "The new protocols commit us to openness — every dataset, every line of analysis code, every step of the verification process will be made public once a discovery is confirmed. The challenge is not secrecy but ensuring that we're telling the public something that's true. As Carl Sagan would say, 'extraordinary claims require extraordinary evidence.'"

Given the large-scale astronomical surveys currently in operation, such as the one taking place at the Vera C. Rubin Observatory in Chile, or which are coming online soon, such as the Square Kilometer Array, it is very possible the astronomer who discovers evidence of extraterrestrial intelligence won't actually be a SETI astronomer.

"More than likely it's not going to be a SETI scientist who is going to make this discovery, it's going to be someone who's looking for something else in the astronomical data but who finds some kind of anomaly that doesn't quite add up," said Garrett.

In this case, they might not be familiar with the protocol of how to handle the discovery, Garrett suggests. They might not necessarily run to the newspapers, but they might declare their discovery on social media before their discovery can be independently verified — and while that could be very exciting, it could also be very daunting. How do they make sure their discovery is accurate and not a mistake? How do they announce this momentous finding to the world? How do they deal with the social media landscape that will judge and question them the minute their words hit the public eye? And what happens after the discovery has been made?

Hence, the eight protocols described in the Declaration of Principles. They have been written to guide the unwitting discoverer through this minefield.

How to handle an alien discovery

The first task in the Declaration of Principles is to verify the discovery is a real one, and not a misidentification.

No astronomer wants to be the boy who cried wolf and declare they've discovered aliens only to have to retract the discovery. Not only would this embarrass them, it would ultimately mislead the public and erode trust. So, verification is the only stage in which the proper protocol is to be circumspect, rather than go straight to the newspapers.

This certainly seems to be easier said than done. "We’ve seen that keeping these discoveries secret, even in a small group, is quite difficult," said Garrett. "The first gravitational-wave discovery leaked before it was published; even BLC-1 [a candidate SETI signal that turned out to be terrestrial radio interference] ended up in The Guardian before it was in Nature, so it’s quite hard to keep control of these things."

Verification could be as simple as having another, independent observatory confirm the detection and the details be peer-reviewed.

Once that is done, then the protocols state that the news be made public, either by the astronomers who made the discovery, or by an institution they are connected to — and that they liaise fully with the media. The findings also have to be reported in detail to the rest of the scientific community and the Secretary General of the United Nations.

Some technical aspects then need to be taken care of, such as protecting the radio frequency on which the discovery was found from terrestrial interference (if it is a radio signal that's been discovered, of course), plus continued monitoring of the signal and careful archiving of evidence, if only to avoid people in the future claiming it to be a hoax.

However, the discovery of extraterrestrial intelligence will open up a can of worms, especially in regards to how society and governments will react, which will depend on the type of alien discovery that has been made — direct contact through a radio signal or a probe in the solar system would probably elicit a much stronger reaction than the discovery of an inscrutable Dyson swarm a thousand light-years away. To better understand how society might react requires the input of academics and experts from many disciplines beyond astronomy.

"I think astronomers need to keep to what we do well, which is look for the evidence," said Garrett. "But then it becomes a societal question; once we’ve made that discovery, what do we do afterwards? I don't think scientists are better placed than anyone else to be able to decide what that should be."

What happens after we finally find aliens?

There are already several inter-disciplinary groups considering the societal implications of an extraterrestrial discovery, including the SETI Post-Detection Hub at the University of St. Andrews in Scotland and the IAA's SETI Permanent Committee, which originally introduced the first version of the Declaration of Principles back in the late 1980s under the stewardship of Michael Michaud. The protocols state that the IAA will maintain a post-detection sub-committee drawing international representation from the scientific, legal, ethics, social science, humanities and communications professions. Their job will be to help advise the public, the scientific community, governments and the United Nations on how to deal with any societal implications, should they ask for that advice.

What the Declaration does not recommend is sending messages to aliens in reply, at least not without international agreement through the U.N.

Messaging Extraterrestrial Intelligence, known as METI, has long been a thorny subject leading to acrimonious debates. While the protocols do not forbid METI (nor do they have any legal standing to forbid anything), they do state that SETI practitioners should participate in international consultations debating the merits of sending a message to the aliens and that no reply should be sent until a decision has been made through the U.N. via various international organizations.

"I'm pretty sure that the IAA SETI committee would say, 'don't reply' and that METI isn't actually a very useful thing," said Garrett. "I've no doubt that is what this committee would decide."

Another thorny subject is UFOs, the focus of Spielberg's Disclosure Day. Garrett says the IAA committee actually discussed whether to include them in the Declaration or not. While most on the committee were against including them on the basis that claims of their existence are not scientifically rigorous, some, including controversial scientist Avi Loeb, argued that they should be.

In the end, Garrett took the decision to only include phenomena detected above the Kármán Line (the official boundary between Earth and space, 62 miles, or 100 kilometers, above the ground) in the protocols.

Not only is this in keeping with the IAA's astronautical remit, but it also recognizes the fact that "the expertise of the committee is in searching for the signatures of intelligence beyond Earth’s atmosphere," said Garrett.

So, while the Declaration does not cover claimed observations of objects appearing to be UFOs in Earth's atmosphere, it would include the detection of alien probes in our solar system, or spacecraft passing through.

"I think there's a subset of our community and committee who can contribute to UAP research," said Garrett. "If UAP research becomes really scientific in the future — which I haven't seen it do so far — but if it does then why not at least have a look at what’s in the protocols and see if it can also be applied to things that are a bit closer to home in terms of phenomena that we don’t understand?"

Would the discovery change our lives?

Ultimately, no one really knows how the discovery of extraterrestrial intelligence will affect humanity. The implications range from there being a huge panic and crisis of confidence in society, as well as in political and religious institutions, to the largest shrug of the shoulders ever as people just get on with their everyday lives.

Garrett questions whether any international organization or institution is really ready to cope with the societal and scientific challenges of the discovery of extraterrestrial intelligence, especially if it is direct contact as opposed to finding a distant technosignature far beyond our solar system.

"Maybe no one can do that, but a professionalization in those kinds of areas would be really useful," he said. To that end, the protocols aim to encourage the development of best practice, so that we would at least have some well-studied guidelines to help us.

"We would really like to get to a place where we can point to a repository of best practice in a number of different areas — the whole range that this topic touches on, which is enormous," said Garrett. "This is why the protocols were originally set-up, and it’s why they have been re-drafted, because we think it is important that there’s a level of responsibility in the kind of things that we do."

The discovery of extraterrestrial intelligence could happen tomorrow, next week, next year, or never. When and if such a momentous discovery is made, however, rest assured that the real disclosure day would happen soon afterwards and that no one would be kept in the dark.

The revised protocols will be officially presented to the scientific community at the International Astronautical Congress in Antalya in Türkiye in October. In the meantime, they are available for anyone to read on the IAA website.

Sorry, true believers: It appears the interstellar comet 3I/ATLAS is indeed just a comet.

Radio astronomers recently hunted for "technosignatures" coming from 3I/ATLAS, which is just the third confirmed interstellar object ever seen in our solar system. As expected, that search came up empty — but it still gathered valuable data, the scientists said.

"The results from 3I/ATLAS show how realistic it is to detect a signal with the technology we have today," study co-author Valeria Garcia Lopez, of Furman University in South Carolina, said in a statement Wednesday (June 3). "That is why it is important to keep searching for technosignatures, even from objects we might not expect to have signals."

3I/ATLAS was first seen on July 1, 2025 by the Deep Random Survey remote telescope in Chile, which is part of the ATLAS (Asteroid Terrestrial-impact Last Alert System) project.

That explains "ATLAS" in the object's name. "3I" indicates that it's the third known interstellar interloper, after 1I/'Oumuamua and 2I/Borisov, which were discovered zooming through our neck of the cosmic woods in 2017 and 2019, respectively.

Telescope observations strongly suggest all three of these visitors are natural objects — namely, comets that were born in other solar systems and subsequently booted into interstellar space, likely via gravitational interactions.

However, it's still worth studying such bodies in detail, according to lead author Sofia Sheikh, who's based at the SETI (Search for Extraterrestrial Intelligence) Institute in California.

"Eventually, our own Voyager spacecraft will be extraterrestrial artifacts in other stellar systems," Sheikh said in the same statement. "Given that, it is important that we understand the natural distribution of interstellar objects so that we will be able to identify any anomalies that could one day be signs of an artificial interstellar object."

There's also the possibility, however remote, that one or more of these interstellar objects could actually be the product of alien intelligence. Indeed, that hypothesis has been advanced to explain 'Oumuamua's perceived weirdness.

So Sheikh and her team studied 3I/ATLAS using the SETI Institute's Allen Telescope Array, a network of radio dishes at the Hat Creek Radio Observatory in Northern California, not long after the comet's discovery. They collected more than seven hours of observations, looking for "narrowband" radio signals — emissions that aren't produced by any known natural phenomenon.

The researchers identified nearly 74 million such signals, which they then culled to about 200 after eliminating human interference and filtering out artifacts caused by 3I/ATLAS' movement. They were then able to explain away those final 200 as well, as signals generated here on Earth or by orbiting satellites.

The new study, which was published online Wednesday in The Astronomical Journal, "sets new constraints reinforcing that 3I/ATLAS is a natural object," SETI Institute officials wrote in the same statement.

"The observations place upper limits on the power of any radio transmitter on or near 3I/ATLAS, ruling out signals stronger than about 10-110 watts, approximately the power of a household appliance, over the detected frequencies," they added.

Earlier this month, the U.S. Department of Defense released what it termed "new, never-before-seen files" on unidentified anomalous phenomena (UAP), tagging it as a historic effort in transparency.

The UAP release came courtesy of the Trump administration's Presidential Unsealing and Reporting System for UAP Encounters, or PURSUE for short.

The posting involves 158 files — documents, photos and videos from NASA, the FBI, Defense Department, and State Department. Additional files are forthcoming, to be issued by the Department of Defense (DoD) "on a rolling basis." In a press statement, DoD Secretary Pete Hegseth remarked that his department is in lockstep with President Trump to bring unparalleled transparency regarding the government's understanding of UAP.

"These files, hidden behind classifications, have long fueled justified speculation — and it's time the American people see it for themselves," Hegseth said.

But just what are we seeing here? Space.com reached out to specialists to unravel what's behind sightings of UAP — or, as they used to be known, unidentified flying objects (UFOs).

'A useful beginning'

For some, there is a "so what" — maybe a ho-hum — reaction to the UAP data release. Those familiar with UFO records, documents, or even astronaut sightings note that almost all of the "never-before-seen" files have long been known.

"I would view this first tranche as a useful beginning in what I hope becomes regular releases of documents not previously available, well documented sighting investigations and videos that aren't stripped of all necessary information," said Mark Rodeghier, president and scientific director of the J. Allen Hynek Center for UFO Studies.

Many of the FBI and other government files were already available, Rodeghier said, but fewer redactions and centralized access are still valuable.

"They allow researchers to check details more carefully and better reconstruct how official agencies received, evaluated and sometimes simply filed away UFO reports," Rodeghier added.

"Short videos and unresolved case summaries can be intriguing, but without the supporting metadata, investigative history and analysis, they are hard to evaluate," he said. "The real test will be whether future tranches provide complete case files, not just provocative fragments. True transparency means context, not just clips."

Similar in view is Robert Powell, an executive board member of the Scientific Coalition for UAP Studies.

"Recent government UAP disclosures have been valuable. They have confirmed that the public and the media regard this phenomenon as a matter of genuine importance," Powell said.

"But redacted files and the absence of credible scientific evaluation are not answers. They are a mandate," said Powell. "Academia and the scientific community can no longer afford to leave this field to institutions that operate in secrecy. The science of UAP must be conducted in the open, by those whose obligation is to the scientific evidence," he said.

More questions than answers

Also taking on "does it matter and who cares" is Alejandro Rojas, a consultant for Enigma Labs, a group appraising UAP via the use of cutting-edge technology and social intelligence.

"The UAP transparency movement didn't start with this administration," said Rojas. "It's been building in Congress for several years, driven by bipartisan oversight and persistent public pressure. What we're seeing now is the continuation of that effort, not the origin of it," he said.

As for the recent DoD release, "it feels somewhat unfinished," Rojas said. "There are many cases with minimal context, missing sensor data, and little accompanying analysis, as if the priority was getting something out the door rather than something useful."

But imperfect data released publicly, Rojas added, is still more valuable than perfect data sitting in a vault. "Even a messy dataset reveals patterns over time, and every case added to the public record is one more data point researchers and citizens can work with. The question is what comes next, because this release raises more questions than it answers," he said.

Missing: context and data

On the lack of context and data, Rojas said that, for any meaningful scientific analysis, you need more than a grainy infrared clip and a one-paragraph summary.

"These reports are largely missing the basics — coordinates, sensor parameters, altitude, speed confirmation. Many cases appear to have been flagged as UAP simply because there wasn't enough data to identify them, rather than because they exhibited genuinely anomalous behavior," said Rojas.

"That's not a criticism of the release," he added, "it's just the reality of what we're working with. Real analysis requires real data, and hopefully future releases include more of it."

Enigma Labs has built a website offering anyone  — researchers, journalists, curious members of the public  — the opportunity to search and explore these files as they come out, rather than hunting through a government portal.

"We're also collecting public sighting reports and giving people a community to discuss and analyze what's being released," Rojas added. "The goal is to make this process as open and accessible as possible, because transparency only works if people can actually find and use the information."

Real and inexplicable phenomena

For the first time in history, the White House and a number of government agencies "have acknowledged that there is a real and inexplicable phenomena occurring on a global basis that demands attention," said Michael Gold, president of Redwire Space, a space and defense company focused on advanced technologies.

Gold has experience delving into uncanny oddness in the skies. He served on NASA's UAP Independent Study Team that ran from 2022 to 2023. He said he's particularly grateful that the DoD (which the Trump administration has unofficially rebranded the Department of War) and NASA acknowledged that the object in the Apollo 17 imagery was real and unknown.

"The most powerful words in science are 'I don't know,' and I appreciate NASA and the Department of War being modest enough to acknowledge when a good explanation doesn't currently exist," said Gold. "Acknowledging anomalies is the first step to discovery, and is how scientific progress is made."

Gold emphasized that it's important to acknowledge the unprecedented nature of the White House's treatment of UAP. "I would like to compare the White House release to similar actions by prior administrations, but I can't, since there are none," he said.

The Trump administration and the agencies involved, Gold said, "should be applauded for supporting transparency despite what I'm certain were incredible and historic challenges to not just releasing information, but even just treating the UAP issue with the seriousness that it deserves."

Beginning, not an ending

In his 2024 testimony before Congress, Gold urged NASA to conduct a review of its archives for UAP.

"Another recommendation I made to Congress and supported by the NASA UAP Independent Study Team was for UAP to be added to NASA's Aviation Safety Reporting System [ASRS]," said Gold.

ASRS provides the U.S. Federal Aviation Administration with confidential data relative to safety anomalies. ASRS has provided the federal government with hundreds of thousands of confidential reports and has successfully operated for years, Gold said.

If UAP were added to the anomalies that ASRS collects, Gold said, every commercial pilot, crew member, and even passengers could act as sensors for UAP, providing a treasure trove of data.

"I hope that more files will be released soon that will show even more definitively anomalous behavior," Gold concluded. "I expect we are at the beginning, not an ending, of a very important moment in the history of science."

The Apollo photos really shouldn't have been part of the big UFO drop.

Last Friday (May 8), the Pentagon released its first batch of declassified "UFO files," responding to a directive that President Donald Trump issued in February.

Many of the 158 files focus on recent sightings by advanced U.S. military sensors — a "misshapen and uneven ball of white light" flying over Syria in October 2024, for example, and a small, bright dot cruising through a field of windmills in that same year. But some of them go back decades — all the way to the 1940s in several cases. (There has apparently been a slight cull or consolidation in the past week; there were 161 files when the drop was first announced.)

The older material includes 14 files related to NASA's human spaceflight programs — two from the Gemini 7 mission to Earth orbit in December 1965, one from Apollo 11 in July 1969, six from Apollo 12 in November of that year, four from Apollo 17 in December 1972 and one from crewed flights to the Skylab space station in 1973 and 1974.

The Apollo 11 file is a "technical crew debriefing," in which astronauts Neil Armstrong, Buzz Aldrin and Michael Collins discuss a few strange things that they saw and experienced during their historic mission. Aldrin, for example, states that he saw "what I thought were little flashes inside the cabin" — a phenomenon that he attributes to "some sort of penetration" or perhaps static electricity.

There are crew debriefings from Apollo 17 and Skylab, too, as well as other transcripts and/or audio excerpts from Gemini 7, Apollo 12 and Apollo 17. The UFO file drop also features photos captured on the lunar surface during those latter two missions, with the Pentagon highlighting supposedly mysterious features.

For example, one Apollo 17 photo "contains three 'dots' in a triangular formation in the lower right quadrant of the lunar sky that is clearly visible upon magnification of the image," its description reads. Another, captured during Apollo 12, "features five highlighted areas of interest, labeled 'Area 1' through 'Area 5,' above the horizon, in which unidentified phenomena are visible."

These photos and transcripts got a lot of attention shortly after last Friday's drop, with outlets like CBS News and Fortune discussing the material. Some of these stories used verbs like "reveal," which is a bit misleading, because this old NASA material has been publicly available for decades.

A number of folks have pointed this out. "Every single image released today from Apollo has simply added yellow boxes to images that have otherwise been public for half a century," astrophysicist Grant Tremblay noted on X on May 8.

"I am making no comment on aliens or UAP here, and am happy to see the release. But a bunch of serious people are suggesting that the Apollo stuff is 'newly declassified,' and that is simply not true," he added in another X post on that same day. (UAP, short for "unidentified anomalous phenomena," is the U.S. government's preferred term for UFOs these days.)

In a May 9 X post, Tremblay guided followers to the Project Apollo Archive on Flickr, inviting them to see the photos in bulk there. Such a perusal will reveal that many Apollo images sport "film defects," he added, highlighting a likely cause of the lunar "UFOs."

Graphic designer Jason Major, a space fan and veteran processor of space imagery, made a similar point.

"This is dumb. There are blue spots, specks, scratches, flares, and bits of crud in almost ALL of the Apollo photos. They were TAKEN WITH FILM CAMERAS IN SPACE — not to mention chemically developed and then scanned by various methods over the course of six decades," Major wrote in a May 8 X post about the Pentagon UFO-file drop.

This isn't to say that you should ignore the files or dismiss folks who are interested in them; some UAP observations are genuinely mysterious, and keeping an open mind is generally a good thing.

But keep a little perspective, too, and know that people have been poring over the Apollo material for longer than most of us have been alive.

Researchers may have just revealed a new way of looking for alien life — it's based on the idea that it isn't just the type of biosignatures that are important, but also how they are organized.

"Our approach could help make the search for life more efficient. If a molecular assemblage shows no life-like organization, that may make it a lower priority target," Fabian Klenner of the University of California, Riverside told Space.com.

Let's break down the concept.

First, it should be noted that life uses and produces a range of biologically useful materials such as amino acids, peptides, proteins, fatty acids and so forth. These compounds are therefore considered potential "biosignatures" — if we find them on another world, it is quite possible that they have been produced by life's processes (life as we know it, at least).

However, these compounds are not exclusively biological — abiotic chemical reactions that have no connection to biology can also produce them, and distinguishing between the two possible sources is one of astrobiology's greatest challenges. For example, methane plumes on Mars could be biological or geological in origin, and the same uncertainty also clouds the detection of phosphine in Venus' atmosphere, or the potential discovery of dimethyl sulfide (DMS) in the atmosphere of the exoplanet K2-18b.

This sows confusion because detecting biosignatures does not necessarily mean we have detected life.

However, Klenner is part of a team led by Gideon Yoffe of the Weizmann Institute in Israel that showed there may be a way to distinguish between biological and abiotic origins.

To do so, they took a leaf out of ecologists' book, where life is measured by two metrics: its diversity and how evenly spread its distribution is.

They focused on two biological compounds: amino acids and fatty acids. Amino acids form long chains called peptides that assemble into proteins that are the workhorses inside biological cells. Fatty acids form part of the structure of those cells. Both can be produced by life or by non-living processes.

"We focused on amino acids and fatty acids because they are central molecular classes for life as we know it and because suitable datasets exist," said Klenner.

Indeed, Yoffe and Klenner's team were able to delve into about 100 datasets including samples from asteroids, fossils, meteorites, microbes, soils and synthetic laboratory samples.

They showed that amino acids are more diverse and more evenly distributed when they are created by living organisms than when produced by non-living processes. Fatty acids are the other way around — they are less diverse and less evenly distributed when created by biology.

This is not a foolproof method of detecting life, warn the researchers. First of all, they have only shown that it works with amino acids and fatty acids. "In principle, similar organizational trends may exist for other molecular classes but this still needs to be tested," said Klenner.

Second, the diversity and distribution of these bio-compounds needs to be placed into context with other molecules, otherwise it is impossible to say how diverse and evenly distributed they really are. This means that it cannot be applied to the DMS detection on K2-18b, as we simply don't know enough about that exoplanet's atmosphere to quantify the diversity and distribution.

"For a single molecule like DMS, the situation is different," said Klenner. "For K2-18b, DMS alone would not be enough for our analysis — we'd need a broader inventory of related molecules."

However, the technique may be more useful closer to home, in our solar system, where samples and datasets are more complete. One useful facet of the research is that the organizational patterns hold up no matter how degraded the biological sample is. For example, fossilized dinosaur eggs retained traces of the distribution and diversity of amino acids and fatty acids.

This could come in useful for Mars, where astrobiologists are searching for evidence of life on the Red Planet from billions of years ago when Mars was warmer and wetter.

"Biological samples do not simply become meaningless once they degrade," said Klenner. "Some organizational information can persist, which makes this approach useful for ancient Mars."

The technique on its own cannot confirm the existence of life — in general, the discovery of alien life would be such a profound revelation that we would need multiple lines of evidence to be absolutely sure.

It can, however, direct us towards the best places to look.

One of those places may be Jupiter's moon Europa, which harbors a global ocean of water beneath a thick shell of ice. Astrobiologists are undecided as to whether that ocean is capable of supporting life or not. While NASA's forthcoming Europa Clipper mission, currently on its way to Jupiter to arrive in 2031, won't be able to look under the ice, it will be able to study possible locations where the ocean has erupted onto the surface.

"One of the instruments on board Clipper, the Surface Dust Analyzer, will be able to measure the abundance ratios of organic molecules in ice grains emitted from Europa," said Klenner. "If families of organic molecules are detected, then our diversity based approach will help interpret whether these molecules look more consistent with abiotic chemistry or biological organization."

The findings were published on May 11 in Nature Astronomy.

UFO enthusiasts just got a big old bone to sink their teeth into.

The Pentagon released its first tranche of declassified "UFO files" on Friday (May 8), responding to a directive that President Trump issued in February.

The new release consists of 161 files, most of which are PDFs recounting investigative reports and eyewitness testimonials (including from a few Apollo astronauts, who saw some strange things near the moon). But there's also quite a bit of imagery, including nearly 30 videos, which feature a range of intriguing unidentified flying objects — or unidentified anomalous phenomena (UAP), as they were recently rebranded.

Space.com combined all of those newly declassified videos into a supercut, which you can see above or via Space.com's YouTube channel. And the new footage is definitely worth a look.

For example, one submission from U.S. Central Command features five seconds of imagery captured in Syria by a full-motion video (FMV) camera in October 2024.

"An accompanying mission report, DoW-UAP-D32, described the UAP as consisting of a 'misshapen and uneven ball of white light,' and reported that a 'light/glare halo effect' occurred at the top of the FMV feed," Pentagon officials wrote in a description of the video.

Another video, submitted by U.S. Indo-Pacific Command, features a nine-second observation gathered in 2024 by an infrared sensor aboard an unspecified U.S. military platform.

"The sensor focuses on an area of contrast that resembles a football-shaped body with three radial projections: one oriented vertically, and two oriented downward at a 45-degree angle relative to the major axis of the main mass," Pentagon officials wrote in a description of the video.

Another 2024 infrared video from the same command has a more artistic feel, and not just because it's considerably longer (100 seconds). It shows a small, bright dot cruising through an array of windmills, looking like a wanderer lost in a ghostly forest of monstrous mechanical trees.

The Pentagon does not attempt to explain the UAP featured in these videos. Indeed, the accompanying text features the following disclaimer: "Readers should not interpret any part of this description as reflecting an analytical judgment, investigative conclusion, or factual determination regarding the described event’s validity, nature or significance."

And, of course, "unidentified" does not necessarily mean "alien" where UAP are concerned. Experts stress that there are a variety of possible earthly explanations for such observations, from advanced drone technology to software bugs and instrument issues.

Releasing the files will get more eyes on UAP footage, which military officials say is a good thing.

"The materials archived here are unresolved cases, meaning the government is unable to make a definitive determination on the nature of the observed phenomena," the Pentagon wrote on the new UFO files website. "This can occur for a variety of reasons, including a lack of sufficient data, and the Department of War welcomes the application of private-sector analysis, information and expertise."

And there will be more files coming soon, according to that page: "Given the scope of this task, the Department of War will be releasing new materials on a rolling basis as they are discovered and declassified, with tranches posted every few weeks."

We may already be signaling other intelligences beyond our solar system, without even trying.

Kunyu City, in the Xinjiang Uygur Autonomous Region of northwest China, hosts huge sprinklers that are irrigating over 1,317 acres (533 hectares) of winter wheat fields on the southern edge of the Taklamakan Desert. Then there's the world's largest cluster of solar farms, a megaproject that covers 235 square miles (639 square kilometers) in Qinghai, China, high on the isolated Tibetan Plateau.

And Earth is dotted with many other humongous, human-made structures like these. To an alien eye, they may be tell-tale signs of intelligent goings-on, betraying our existence and hinting at our capabilities.

Visible signaling

People who want to reach out to E.T. have long recognized the communication potential of such "megastructures." In the nineteenth-century, for example, multiple folks advanced proposals for broadcasting "we're here" messages via visible signaling.

One popular type of proposal involved displaying supposedly meaningful figures on parts of our planet that would be visible from the extraterrestrial target of choice.

In these plans, recalled Douglas Vakoch, president of Messaging Extraterrestrial Intelligence (METI) International in San Francisco, huge diagrams would be etched on large expanses of land here on Earth. For example, a visual representation of a right triangle could be shown, he said, with a square attached to each side of the triangle to illustrate diagrammatically the Pythagorean theorem.

By clearing gargantuan stretches of forest, Vakoch said, such geometrical concepts could be seen by intelligent aliens scanning the sunlit side of the Earth. This intended, symbolic representation of the Pythagorean theorem would be huge enough to be seen from the moon — even by inhabitants of Mars.

Hello, lunarians!

Vakoch said that among the early proponents of displaying pictures to communicate with extraterrestrials was the illustrious mathematician Karl Friedrich Gauss. In 1826, he was credited with suggesting such an approach for communicating with potential lunarians, inhabitants of Earth's moon.

"It was Gauss whose idea of inscribing the Pythagorean theorem in Siberian forests has often been touted as an early proposal for communicating with lunarians, although it's unclear whether Gauss actually said this, or whether it's only attributed to him," Vakoch told Space.com.

Similarly, there were thoughts of perhaps creating large canals in the Sahara Desert filled with kerosene, then torched to flash a similar transmission from the dark side of Earth, the METI expert explained.

Strip malls and data centers

Vakoch's favorite early proponent of interstellar communication is Francis Galton, an English polymath (and, less admirably, the originator of eugenics during the Victorian era). In 1896, Galton published an article in the "Fortnightly Review" called "Intelligible Signals Between Neighbouring Stars."

"Signals have to be devised that are intrinsically intelligible, so that the messages may be deciphered by any intelligent man, or other creature, who has made nearly as much advance in pure and applied science as ourselves," Galton emphasized.

So a bottom line: Are we viewed by other starfolk as a bunch of busy beavers terraforming our own planet while inadvertently waving to other worlds? If we build a big enough strip mall or AI data center, maybe we'll find out.

NASA's Curiosity Mars rover has found a diverse mix of organic molecules on Mars, including chemicals widely considered building blocks for the origin of life on Earth. The finding marks the first time a new kind of chemical experiment has been performed on another planet.

Curiosity rover has been dutifully probing Mars' Gale crater and Mount Sharp since the robot plopped down on the Red Planet on Aug. 6, 2012. The car-sized Mars rover is now wheeling about in the Glen Torridon region of Gale crater, a place that scientists believe could have supported conditions that were favorable to supporting ancient life, if it was ever there in the first place. While in the region, Curiosity recently utilized its onboard Sample Analysis at Mars (SAM) instrument suite, built to search for compounds of the element carbon that are associated with life and investigate ways in which these compounds are generated and destroyed in the Martian ecosphere.

Curiosity's SAM instrument was able to use a chemical known as tetramethylammonium hydroxide (TMAH) to detect organic molecules in the region's clay-rich sandstone. The newly identified chemicals include nitrogen and sulfur-bearing molecules that are similar to the raw material that helped spur life on Earth. However, the experiment can't tell if the chemicals come from ancient Martian life or non-biological geological processes.

The study of Curiosity's first SAM TMAH experiment was led by Amy Williams, an associate professor in the Department of Geological Sciences at the University of Florida in Gainesville. The research has been published in the journal Nature Communications.

"This experiment and its results have been a labor of love and science," Williams told Space.com. "This was the first time that TMAH had been used on another world and our team worked extensively to interpret and confirm the molecules detected in this first-of-its-kind experiment."

Clay-bearing sandstones

Curiosity's experiment detected more than 20 organic molecules from clay-bearing sandstones in the roughly 3.5-billion-year-old Knockfarrill Hill section of Glen Torridon. The variety of organic molecules observed suggests that some chemical diversity has been preserved in ancient Martian sediments despite billions of years of diagenesis (the process by which sediment turns to rock) and radiation exposure.

"We propose that this suite of organics represents TMAH thermochemolysis breakdown products from ancient organic macromolecular material that has been preserved in billions-of-years-old sedimentary rocks in Gale crater," explains the research paper.

Williams said the rover's discoveries were confirmed with other instruments aboard. "We iterated on molecule identifications using some of the SAM flight spare equipment to confirm our findings," Williams said. "I think the time was well spent, as we now have evidence that the suite of molecules broken apart by the TMAH reagent derived from more complex macromolecular carbon that is preserved in the martian subsurface."

Native martian organics

The newly-issued paper explains that the ongoing characterization of organic matter on Mars "is a pillar of modern robotic exploration, as space agencies send rovers and landers to explore Mars' past and present habitability and to search for signs of life."

Furthermore, within a decade of time, researchers have advanced from the search for organic molecules on Mars to identifying native Martian organics.

"We are now poised to address the source of these organics, whether exogenous (e.g., meteoritic, cometary, or interplanetary dust particles) or endogenous (e.g., abiotically or biologically produced)," Williams and colleagues report in the study.

As noted in the new research paper, the confirmation of macromolecular organic matter "supports the possibility that future optimized TMAH thermochemolysis experiments can liberate ancient biosignatures preserved in macromolecules on Mars (if present)."

The results of the SAM TMAH experiment "expand the library of confirmed and suggested organic molecules preserved over deep geologic time in the Martian near-surface and confirm the presence of macromolecular carbon on Mars," the paper concludes.

Different locations on Mars

The scientists say that Curiosity's discoveries could tie into observations from NASA's other on-duty Mars rover. "Our findings are aligned with some observations of organic matter with the Perseverance rover," Williams said.

The TMAH experiment on Curiosity was used to identify cyclic (or aromatic) organic compounds that derived from more complex macromolecular carbon, Williams said. Meanwhile, the Perseverance rover has used a different instrument to find evidence for both cyclic organic compounds and macromolecular carbon.

"We now have evidence for diverse and potentially complex organic matter, preserved in different locations on Mars and detected with different instrument suites. This suggests that organic carbon is better preserved over long time periods on Mars than we expected, given the harsh radiation environment," Williams said.

Future life detection instruments

These new results could be useful for future life detection instruments done robotically or by astronauts, Williams said, calling the TMAH experiment a "trailblazer for upcoming planetary missions."

Versions of the TMAH experiment are flying with the Mars Organic Molecule Analyzer (MOMA) on the European Space Agency's Rosalind Franklin rover destined for Mars' Oxia Planum plain, and on the Dragonfly Mass Spectrometer (DraMS) instrument being installed on the Dragonfly rotorcraft destined for Saturn's moon Titan.

Williams said that the new results can help inform the experimental design for these future missions.

"The TMAH experiment revealed that macromolecular carbon is preserved over long time periods in some of the rocks on Mars. This is powerful information for future life detection missions and instruments, as we now know that larger molecules that could have been made by life can be preserved in the Martian near surface," Williams added.

Next generation instruments, Williams concluded, "can focus on techniques to more fully extract these organics and glean new information about their identity and potentially their origin, be it geologic, meteoritic, or biologic."

The truth is reportedly out there. But in the case of flying saucers and unidentified anomalous phenomena, what's truly going on seems elusive.

Making it all the more intriguing is U.S. President Donald Trump's recent directive "to begin the process of identifying and releasing government files related to alien and extraterrestrial life, unidentified aerial phenomena (UAP), and unidentified flying objects (UFOs) and any and all other information connected to these highly complex, but extremely interesting and important, matters."

But "disclosure" — in whatever form it takes — could ignite a powder keg of implications. And discussions of disclosure are particularly timely these days, given that Steven Spielberg's highly anticipated film "Disclosure Day" is set for release this June. Space.com reached out to a diversity of experts on the topic, obtaining a wide swath of swing and sway.

Appetite for disclosure

Greg Eghigian is a professor of history and bioethics at Penn State University in University Park, Pennsylvania. He is author of "After the Flying Saucers Came: A Global History of the UFO Phenomenon" (Oxford University Press, June 2024).

Eghigian said that, if you look at the history of the UFO phenomenon, all government gestures aimed at disclosing and declassifying UFO-related information have generated two basic responses.

"There have been those who insist that the materials published definitively show there to be nothing out of the ordinary in sightings and reports," said Eghigian. But these folks are invariably balanced out by others who point to what the documents redact, or don't include, and insist that the government is still keeping vital secrets about UFOs, he added.

"The existence of secrecy means even apparent openness can be suspected of disguising more secrecy," Eghigian said. "The appetite for disclosure is likely to never be satisfied."

Keep an open mind

Steven Dick has written a book on the impact of discovering life beyond Earth: "Astrobiology, Discovery, and Societal Impact" (Cambridge University Press, 2018).

It doesn't deal much with the UFO/UAP question, Dick said — what he calls "direct terrestrial contact" in his matrix of contacts, which is noted in the book's section on "Humanistic Implications of Discovering Life Beyond Earth."

However, Dick said that UAPs are logically and in principle "one of the scenarios that should be subject to a serious research program, which may or may not have anything to do with ETs."

In terms of "disclosure" of UFO/UAP information, Dick said he's trying to keep an open mind.

As a member of Avi Loeb's Galileo Project at Harvard University, Dick said he prefers "building equipment to acquire new data rather than going over old blurry images. I doubt much will be revealed in any 'disclosure.'"

The goal of the Galileo Project, according to its website, "is to bring the search for extraterrestrial technological signatures of Extraterrestrial Technological Civilizations (ETCs) from accidental or anecdotal observations and legends to the mainstream of transparent, validated and systematic scientific research."

Fantastic claims

In a spate of recent Congressional hearings, fantastic claims were made about alien technologies, bodies and other assertions, Dick noted.

"But in the end, when it comes to revealing where these technologies and bodies are located, the answer is always 'classified.' I'm all for disclosure, and there are undoubtedly massive records, but I would be very surprised if anything very sensational is revealed," he said.

As a government employee for 30 years, six of them at NASA, Dick said he finds it hard to believe such an amazing secret could have been kept over all these years.

The impact of discovering alien intelligence will vary with the distances involved, with a Type 1 close encounter (UFO/UAP) having most impact due to proximity, Dick said. "Even if the alien bodies or technologies are discovered from past visits, it would change our scientific, theological, philosophical and cultural worldviews, in a number of ways," he said.

Even contemplating the likely existence of ET at a distance, Dick advised, has already spawned the new field of "astrotheology."

Bureaucratic dimension

Loeb has been monitoring the disclosure implications, and has summarized them in essays and videos. The Harvard astronomer said there is a bureaucratic dimension to President Trump's comments on aliens and UAP.

"Administrators in intelligence agencies may not want to publicly acknowledge that there are objects they cannot identify, especially given the large budgets allocated for national security," Loeb said.

"Classification limits the number of people who can review the data, including members of Congress," so it makes sense that such information remains classified, he added.

"One step that can be taken immediately is to declassify events from 50 years ago," Loeb said. "Technologies used half a century ago are no longer strategically sensitive. Releasing older data could significantly advance scientific research."

Loeb said he would be delighted to help the government analyze declassified incidents.

Mixture of concern

"I do not anticipate that there will be any 'disclosure,'" said Carol Cleland, a professor in the Department of Philosophy at the University of Colorado Boulder and an affiliate of the SETI (Search for Extraterrestrial Intelligence) Institute.

If there were one, however, it "would be rejected by some people as bogus and welcomed with religious fervor by others," she told Space.com.

Cleland said that many people would shrug the disclosure news off and go on with their lives.

"A few people, including myself, would react with a mixture of concern about the intentions of the intelligences that have been hiding their presence and spying on us — for who knows how long — and excitement over the discovery that there are other intelligences in the universe," Cleland said. "For scholars and scientists, it would be revolutionary."

Can we handle the truth?

"I know that the public says we can handle the truth. I'm not entirely sure that's true, because we don't really know what the truth is," said George Knapp, a veteran newsman and long-time investigator of UFOs who's based in Las Vegas.

Speaking earlier this year to Ron Futrell, host of the popular "Mystery Wire" internet program, Knapp expressed his thoughts on disclosure.

"A lot of folks think it's ETs from other planets, and we can probably handle that. We've seen enough movies and TV shows over the years," Knapp said. "But I can foresee some strange possibilities that might be truly upsetting to people's religious beliefs and their fundamental beliefs about how humans evolved," he said.

"We think we can handle the truth," Knapp added. "Yeah, we think that our government knows the truth. I'm not sure either of those are true."

Entering a planet's atmosphere is a dangerous maneuver for any spacecraft, as it must withstand the intense frictional heat generated by high-speed contact with atoms and molecules.

That's why landers and rovers have heat shields. And new research from the Grainger College of Engineering at the University of Illinois Urbana-Champaign suggests that an atmosphere's composition has a big impact on how heat shields work.

A heat shield "breathes" when it hits the atmosphere. The surface of the shield begins to burn away, in a process called ablation. To mimic the hypersonic speed of a spacecraft's entry, a team of researchers led by Francesco Panerai, a professor in the Department of Aerospace Engineering, experimented with heat shields in the Plasmatron X wind tunnel at the Center for Hypersonics and Entry System Studies, which is housed a few blocks from the university's campus.

"What was very surprising about the study is that, when we changed the gas, the ablation phenomenon behaved in different ways," Panerai said in a March 12 statement. "In a classical air environment where you have oxygen present, the ablation happens in a steady way. The flow around the spacecraft erodes the surface, and particles get ejected as a constant stream."

When material from the outer layer of the heat shield erodes, some of it can collect on the surface of the shield, potentially clogging up some areas and preventing the material below from "breathing." This can impact how well the shield performs. In the new study, the researchers found that changing the gases that the shield comes into contact with also changes its performance.

"When the oxygen is removed, this phenomenon becomes unsteady. Intermittent bursts of particles are ejected and, at times, the process becomes violent," Panerai said. "I've been around ablation research for over 15 years, and I've never seen this. We were all really surprised when we first observed this behavior in the tunnel."

Understanding how an atmosphere's composition affects heat shields is important, Panerai said, because NASA is getting Dragonfly, a robotic rotorcraft, ready for a 2028 launch toward the huge Saturn moon Titan. Titan has a thick atmosphere that's quite different from that of Earth: It's composed of about 95% nitrogen and 5% methane, whereas ours is 78% nitrogen and 21% oxygen.

Dragonfly will study Titan's surface, which could give scientists clues on whether or not the moon's hydrocarbon lakes and rivers hold molecules that are a precursor for life.

"Although this work doesn't directly influence heat shield design, it does have very profound implications on the physics of the material — on the way the material behaves at extreme temperatures," Panerai says. "Understanding at what conditions this phenomenon becomes prominent in flight can help us design better heat shields."

The study was published Feb. 5 in the science journal Carbon.

Back in 1961, astronomer Frank Drake put chalk to board and devised a formula to estimate the number of communicative civilizations in the Milky Way. Just how many alien societies exist and are detectable?

And there's also the paradoxical query asked a decade earlier by physicist Enrico Fermi. It seems like ET should be out there, given the vast amount of cosmic real estate. So, where is everybody?

Over the decades, researchers have been trying to come up with answers to these questions. The search for extraterrestrial intelligence (SETI) is a mix of technology, super-smart software and patience, along with creative thinking. For example, maybe the problem isn't us or our methods. Perhaps ET is a party pooper, refusing to join in on any interstellar discourse.

Declining to speak?

In a new research paper, Erik Geslin notes that the Drake Equation asks how many civilizations beyond Earth might exist.

"My work asks whether they would actually want to speak with us," Geslin told Space.com. "What we call the 'Great Silence' may not reflect absence, but refusal."

In the view of Geslin, an associate professor of interactive media at Noroff University College in Norway, a civilization capable of interstellar travel may also be one that has moved beyond conquest, excess and ecological self-destruction.

Does that mean ET might be introverted as well, feeling no real urge to reach out to its cosmic neighbors?

"Advanced extraterrestrials may not be shy, they may simply be prudent," Geslin said. "If extraterrestrial civilizations are biocentric or ecocentric, humanity may not yet appear to them as a safe partner for contact. Such civilizations might simply be cautious."

Planetary prudence

Other starfolk may understand very well the potential risks involved in interacting with humanity, a species that is still strongly anthropocentric, heavily resource-driven and often conflict-prone, according to Geslin.

"What we interpret as silence might therefore not reflect fear, but prudence! Perhaps even a kind of ethical restraint. In that sense, their behavior could resemble a principle of non-interference," he said.

But as for us Earthlings, we've been busy beavers, in terms of broadcasting signals into space and putting an ear to the cosmos in the hope of making contact. We have even planted messages to "the others" out there on outward-bound spacecraft, like NASA's Pioneer and Voyager probes.

"But sending friendly messages does not necessarily mean that we appear as a friendly civilization when viewed from the outside. An advanced society would likely take its time to observe us before considering any form of interaction," Geslin said. "They might study our communications, our media, our films, simulations, games and social networks, all of which reveal something about who we are."

Line of thinking

Geslin said that it doesn't take much effort to simply observe the state of our planet and the way our civilization interacts with its biosphere.

"From that perspective," he said, "our signals might reveal a species that is inventive and technologically creative, but also ecologically unstable and often destructive toward both its environment and its own members."

This line of thinking led Geslin to introduce a "contact-willingness factor" into the Drake framework.

"My work explores a different question: Even if they do exist, would they actually want to communicate with us?" he said. "My hypothesis is that the answer may depend not only on technological capability, but also on the cognitive, ethical and ecological maturity of those civilizations, and on our own."

Curiosity: a powerful force

That said, curiosity is a powerful force. Technological evolution is closely linked to creativity, exploration and the desire to understand the unknown.

"It is therefore possible that some civilizations might eventually decide that the potential benefits of contact outweigh the risks. Exploration always involves some degree of uncertainty," Geslin explained.

"Personally, however, I suspect that civilizations capable of sustaining themselves long enough to achieve interstellar travel may also have developed a very deep awareness of ecological balance and systemic fragility," he added. "If so, they might be extremely selective about whom they choose to engage with."

Geslin's paper, "Incorporating an exopsychological biocentric contact-willingness factor into the Drake Equation," will appear in the August issue of the journal Acta Astronautica. You can find it online here.

Moons orbiting starless "rogue" planets could stay warm enough to host liquid water for billions of years, a new study suggests, potentially creating long-lived habitats for life in the depths of space.

Using computer models, researchers found that temperatures on an Earth-size moon orbiting a Jupiter-like rogue planet could remain warm enough to support liquid water on its surface for up to 4.3 billion years — nearly as long as Earth has existed.

"The cradle of life does not necessarily require a sun," study lead author David Dahlbüdding, a researcher at the Ludwig Maximilian University of Munich in Germany, said in a statement.

The new study focuses on natural satellites of exoplanets, known as exomoons, specifically those orbiting free-floating rogue planets. Astronomers have yet to confirm the existence of an exomoon beyond doubt, but mounting circumstantial evidence suggests the first discovery may not be far off.

Rogue planets are byproducts of chaotic young planetary systems, where close gravitational encounters can fling worlds out of orbit around the host star and into interstellar space. Recent research suggests that these nomadic planets have a significant probability of retaining their moons even after being ejected. The violent process can, however, dramatically reshape those moons' orbits, stretching them into elongated paths around their planets.

As a moon moves closer to and farther from its planet along such elliptical paths, the planet's gravity repeatedly squeezes and flexes its interior. In our own solar system, this process powers the intense volcanic activity of Jupiter's moon Io and helps keep subsurface oceans from freezing on icy moons such as Europa and Saturn's Enceladus.

Known as tidal heating, the process generates internal heat through friction and, according to the new study, could be strong enough to keep liquid water oceans from freezing even in the cold of interstellar space.

Whether that heat can remain at the surface depends largely on the moon's atmosphere, the researchers say. Earlier studies suggested that carbon dioxide could provide enough greenhouse warming to keep such moons habitable for up to 1.6 billion years. In the extreme cold of interstellar space, however, carbon dioxide can condense, causing the atmosphere to collapse and allowing heat to escape, the new study notes.

Hydrogen, however, behaves differently under thick, high-pressure conditions, the study argues. The team's simulations show that, when hydrogen molecules collide, they can briefly absorb heat that would otherwise radiate away into space. This allows a dense hydrogen atmosphere to act like an insulating blanket, trapping warmth far more effectively.

The results, published in February in the journal Monthly Notices of the Royal Astronomical Society, show that under these conditions some exomoons could remain warm enough for liquid water — and therefore be potentially habitable for life as we know it — for up to 4.3 billion years.

The findings could "significantly broaden the spectrum of possible environments that could harbor life," the statement read, suggesting that "life could arise and endure even in the darkest regions of the galaxy."

NASA is one step closer to sending a drone mission to another world.

Technicians at the Johns Hopkins Applied Physics Laboratory (APL) in Maryland have begun building and testing the nuclear-powered Dragonfly rotorcraft, which will launch toward the huge Saturn moon Titan in 2028.

"This milestone essentially marks the birth of our flight system," Elizabeth Turtle, Dragonfly principal investigator at APL, said in a NASA statement on Tuesday (March 10).

"Building a first-of-its kind vehicle to fly across another ocean world in our solar system pushes us to the edge of what's possible, but that's exactly why this stage is so exciting," Turtle added. "The team is doing an outstanding job, and every component we install and every test we run brings us one step closer to launching Dragonfly to Titan."

The car-sized Dragonfly will be the second rotorcraft to explore the skies of a world beyond Earth. The first was NASA's Mars helicopter Ingenuity, whose fuselage was only the size of a tissue box. The solar-powered Ingenuity was designed for just a handful of hops but survived an ambitious flight campaign that lasted nearly three years, from April 2021 to January 2024.

Building on what NASA learned, Dragonfly will be bigger — and powered by nuclear energy, not the sun. The Titan drone is also a full mission, costing about $3.35 billion; Ingenuity was a technology demonstrator with a price tag of just $85 million.

Dragonfly is expected to launch in 2028 toward Titan, the largest moon of Saturn and second-largest satellite in the solar system, behind Jupiter's Ganymede. Titan is thought to be rich in the precursor molecules of life as we know it, which makes it an exciting target for scientists, but it has been studied up close just once — by the European Huygens lander, which survived for a few hours in Titan's skies and on its surface on Jan. 14, 2005.

After touching down on Titan, Dragonfly aims to "explore a range of diverse sites to study the chemistry, geology and atmosphere of the terrestrial moon and ultimately advance our understanding of life's chemical origins," NASA officials stated. But first, the mission needs to be readied for space.

At APL, the first weeks of testing will focus on the spacecraft's integrated electronics module — a sort of "brain" for the mission that focuses on items like guidance, navigation and data handling — and power-switching units.

Testing and integration is expected to continue into early 2027. The spacecraft will next be shipped to Lockheed Martin Space in Littleton, Colorado for systems testing, before a brief return to APL to assess how Dragonfly will do in the space environment. APL will send Dragonfly to NASA's Kennedy Space Center no earlier than spring 2028, to launch aboard a SpaceX Falcon Heavy rocket.

Dragonfly's protective shell for flying through space is also being tested: the shell finished aerodynamic assessments in wind tunnels at NASA's Langley Research Center in Virginia and is now in the integration and testing stage at Lockheed Martin. APL is also assessing insulating foam intended to keep Dragonfly from freezing in Titan's frigid atmosphere, and other items like the science payload and flight radio are also coming together.

While several years lie between now and launch, entering the build-and-test phase is a big milestone.

"We've spent years designing and refining this amazing rotorcraft on computer screens and in laboratories, and now we get to bring all those elements together and transform Dragonfly into an actual flight system," Annette Dolbow, the Dragonfly integration and test lead at APL, said in the same statement.

SETI might not have succeeded in finding alien life yet because space weather around other stars could be disrupting aliens' attempts to send radio messages out, according to a new study that tries to make sense of why the universe seems so quiet.

"Space weather" describes the electromagnetic disturbances produced by gusts of radiation in a stellar wind or coronal mass ejections (CMEs) from a star. These events spew a lot of plasma and electrons into interplanetary space around a star, and plasma and electrons are like kryptonite to coherent radio signals.

Various deleterious effects occur when radio waves interact with a dense patch of charged particles. For example, scientists working in SETI, the search for extraterrestrial intelligence, already factor in the consequences of electron dispersion in the interstellar medium between stars. When a radio wave encounters an electron in interstellar space, lower radio frequencies interact more strongly than higher frequencies, causing the lower frequencies to be delayed and arrive at their destination later than higher frequencies. A broadband signal stuffed with many frequencies would be seriously affected by this dispersion, which is why SETI scientists expect that aliens would be transmitting narrowband signals of fewer frequencies instead.

The other reason why SETI looks for narrowband signals, with bandwidths of just a few hertz, is that nothing known in nature produces such a tightly constrained radio signal. So, if we detected one, we'd know it was more than likely artificial.

However, until now no one had quantified the effects of plasma and electrons spewed out by activity on stars. If a technological species on a distant exoplanet wanted to beam a message into deep space, the space weather in its home system could negatively affect the characteristics of that signal.

"SETI searches are often optimized for extremely narrow signals," Vishal Gajjar, of the SETI Institute in Mountain View, California, said in a statement. "If a signal gets broadened by its own star's environment, it can slip below our detection thresholds, even if it's there, potentially helping explain some of the radio silence we've seen in technosignature searches."

The most likely impact of space weather on narrowband radio signals is something called diffractive scintillation. This can cause a signal to become smeared across a much wider range of frequencies when it interacts with plasma from a star. Whereas the initial narrowband signal might have a strong power across just a few frequencies, the smearing spreads that power across more frequencies, reducing the strength of the signal.

However, identifying the problem was only the first step. Gajjar and his SETI Institute colleague Grayce Brown wanted to take it one step further and quantify the effect of space weather so that it can become easier to mitigate during SETI searches.

To do so, the duo first had to quantify the effect in our own neighborhood, analyzing radio signals between Earth and space missions exploring our solar system. Gajjar and Brown calibrated how fluctuations in the solar wind and bursts from CMEs can affect narrowband signals, and averaged that over time. They then used the example of our sun as a basis for calibrating the broadening effect of space weather on signals around two main types of stars: sun-like stars, and red dwarfs, which are the smallest, coolest type of star, making up three-quarters of all the stars in the Milky Way galaxy.

Stars much more massive than the sun were left out of the study, since their lifetimes are likely too short for technological life to have time to develop on any orbiting planets.

To emphasize their point, Gajjar and Brown simulated a SETI search of the million closest sun-like and red dwarf stars and incorporated the effects of space weather based on the known activity of such stars.

The simulation depicted a search for alien signals in the region around 1 GHz, which is the most common frequency band in which to search. Radio emission from interstellar hydrogen, for example, is at 1.42 GHz.

According to the simulation, 70% of stars result in signals being broadened in frequency by more than 1 Hz, and 30% of stars produce a broadening of more than 10 Hz, particularly red dwarf stars, which are noted for their strong stellar activity.

Even more seriously, were a CME to occur at the time a signal is transmitted, it could incur a broadening in excess of 1,000 Hz, rendering a signal completely invisible to detectors focused on very narrowband signals.

However, now that we know that this can happen, efforts can be made to minimize its effect — just like how we can estimate the degree of dispersion by the interstellar medium, or how algorithms can remove the Doppler drifting in frequency caused by the motion of a transmitter on a planet orbiting its star.

"By quantifying how stellar activity can reshape narrowband signals, we can design searches that are better matched to what actually arrives at Earth, not just what might be transmitted," said Brown.

For 66 years and counting, SETI has been searching for evidence of technological life in the universe but has so far found nothing. For example, the citizen science project SETI@home, which began in 1999, is down to its last 100 candidate signals and hopes are not high that any of them will turn out to be ET.

Some researchers refer to this failure to find technological aliens as the "Great Silence," but could this space weather effect quantified by Gajjar and Brown be the cause? It is possible that it has at least contributed to the Great Silence, depending upon how many transmitting species are out there. However, just as we monitor the sun and space weather in our solar system, it would seem fair to expect aliens sufficiently technologically proficient to beam messages into the cosmos to also know of their own star's space weather, and wait for calmer periods before transmitting.

This cannot be guaranteed, though, especially if the transmitter is always switched on (which would suck up a lot of power), or if it is an automated transmitter. Gajjar and Brown propose that far from a "Great Silence," the universe could be awash with noisy messages, and we've just not been tuned in enough to hear them.

The research was published on March 5 in The Astrophysical Journal.

A remarkably hardy bacterium can survive pressures similar to those generated when asteroid impacts blast debris off Mars, a new study has found, suggesting that microbes could endure interplanetary journeys and potentially seed life on other worlds, including Earth.

The findings, published earlier this week in the journal PNAS Nexus, may prompt scientists to reconsider where life could exist across the solar system and could lead to a reassessment of "planetary protection" rules designed to prevent contamination between worlds.

"Life might actually survive being ejected from one planet and moving to another," study co-author Kaliat Ramesh, a mechanical engineer at Johns Hopkins University in Maryland, said in a statement. "This is a really big deal that changes the way you think about the question of how life begins and how life began on Earth."

The new findings lend support to a long-debated theory known as lithopanspermia, which proposes that life can spread between planets by hitching a ride on fragments of rock blasted into space by massive impacts. The idea remains unproven, however, and clear evidence of past or present life on Mars remains elusive (though scientists have made some intriguing finds lately).

For the study, Ramesh and his colleagues tested the endurance of Deinococcus radiodurans, an exceptionally resilient bacterium found, among other places, in Chile's high-altitude deserts. With a thick outer shell and a remarkable ability to repair its own DNA, D. radiodurans is famously tolerant of intense radiation, freezing temperatures, extreme dryness and other harsh conditions similar to those found in space. It has been nicknamed "Conan the bacterium," after all.

To simulate the forces involved in an asteroid impact, the researchers sandwiched samples of D. radiodurans between two steel plates. Using a gas-powered gun, they fired a projectile at roughly 300 mph (480 kph), subjecting the microbes to pressures between 1 and 3 gigapascals. For comparison, the pressure at the deepest part of Earth's oceans — the crescent-shaped Mariana Trench in the western Pacific Ocean near Guam — is about 0.1 gigapascal, meaning even the lowest pressure in the experiment was roughly 10 times greater.

Nearly all of the microbes survived impacts generating 1.4 gigapascals of pressure, while about 60% remained alive at 2.4 gigapascals. At lower pressures, the cells showed no signs of damage, though researchers observed ruptured membranes and some internal cellular damage at higher pressures, the study reports.

"We continuously redefine the limits of life," Madhan Tirumalai, a microbiologist at the University of Houston who was not involved with the new study, told The New York Times. "This paper is another example."

As the pressure increased, the researchers also detected heightened activity in genes responsible for repairing DNA and maintaining cell membranes.

"We expected it to be dead at that first pressure," Lily Zhao, a mechanical engineer at JHU who led the experiment, said in the statement. "We started shooting it faster and faster. We kept trying to kill it, but it was really hard to kill."

The experiment eventually ended, the statement read, because the steel structure holding the plates "fell apart before the bacteria did."

Mars might have its own defense mechanism against life from Earth, in a kind of reverse of "The War of the Worlds" scenario that could help protect the Red Planet from contamination by terrestrial bugs.

Scientists led by Corien Bakermans, a professor of microbiology at Penn State University, were experimenting with exposing tardigrades, which are microscopic animals nicknamed "water bears" that grow to at most half a millimeter in length, to simulants of Martian regolith.

The intention was to determine how well tardigrades did in the regolith, with an eye on one day converting Martian regolith — which is dead, inorganic dirt — into organic soil in which plants can grow. For that to happen, life needs to be able to flourish in the regolith in order to help fertilize it. Think of microbes and earthworms in Earth's soil, continually processing the soil to keep it healthy.

Simulants are representations of real Martian regolith. Because we have no samples of Martian regolith on Earth, scientists are forced to replicate it in simulants based on readings of its chemical composition by Mars rovers. In particular, Bakermans' team used two simulants, both informed by measurements from NASA's Curiosity rover, which is exploring Gale Crater on Mars.

One of the simulants, known as MGS-1, is designed to mimic the general properties of regolith across Mars. The other simulant, OUCM-1, is designed to more specifically represent the Rocknest area in Gale Crater, where Curiosity took the sample that the simulant is based on.

"We know a lot about bacteria and fungi in simulated regolith, but very little about how they impact animals — even microscopic animals, like tardigrades," said Bakermans in a statement. "We investigated the specific, isolated impact of the regolith on tardigrades."

What Bakermans' team found shocked them. Tardigrades have two states of living: active and dormant, the latter usually resulting from dehydration. When exposed to MGS-1, the tardigrades entered dormancy within two days.

"For the MGS-1 simulant, we saw significant inhibition — reduced activity — within two days," said Bakermans. "It was very damaging compared to OUCM-1, which was still inhibitory but much less so. We were a little surprised by how damaging MGS-1 was, [so] we theorized that there might be something specific in the simulant that could be washed away."

So the team did just that, washing a sample of MGS-1 and then applying a new batch of tardigrades to it. This time the little water bears did much better, showing only minor ill effects.

However, the identity of whatever it was that affected the tardigrades remains uncertain.

"It seems that there's something very damaging in MGS-1 that can dissolve in water — maybe salts or some other compound," said Bakermans. "That was unexpected, but it's good in a sense, because it means that the regolith's defense mechanism could stop contaminants. At the same time, it can be washed to help support plant growth or prevent damage to humans who come in contact with it."

NASA has a planetary protection office, which is currently led by the microbiologist J. Nick Benardini. "Planetary protection" brings to mind defending Earth from slavering aliens, but it's actually mostly focused on the reverse scenario: protecting other worlds from contamination by microbes from Earth.

There are two main reasons why we might want to do this. One is that, if life does exist on another planet — and it is still an open question for Mars, given the ambiguities in the measurements made by NASA's Viking landers and the anomalous methane plumes that could be biological or geological in origin — then the introduction of microbes from Earth could potentially destroy that alien biosphere. Any microbial life native to Mars could have evolved to resist the toxic element(s) in the planet's regolith, as extremophiles do here on Earth.

The other reason is that, even if terrestrial contamination doesn't destroy the native biosphere, it will confuse our measurements. If we detect life on Mars, how could we be sure that it is truly native and not a microbe imported from Earth that has contaminated the Red Planet?

It is for this reason that all missions that land on Mars, such as the Curiosity and Perseverance rovers, undergo the strictest regime of sterilization before launch. Guidelines from COSPAR, the Committee on Space Research, state that any mission to land on a planetary surface that may host a biosphere must have only a 1-in-10,000 chance of carrying an Earthly microbe to that world. (Complete sterilization is impossible as you could never be sure you've got all the microbes.)

However, if Mars has its own defenses, then things might be a little less worrisome from a planetary protection perspective, and constraints on future missions could be loosened.

"With this research, we're looking at a potential resource for being able to grow planets as part of establishing a healthy community — but we're also looking at whether there are any inherent damaging conditions in the regolith that could help protect against contamination from Earth, which is a goal of planetary protection," said Bakermans.

Her team's findings do seem to be the best of both worlds. Mars' surface no longer has running water — it is far too cold and its atmosphere too thin — but there is ice at the poles and permafrost at mid-latitudes to extract water from. So as it stands, Mars' regolith may be able to defend against Earthly contamination, especially if it is accidental.

These findings are consistent with previous experiments that have found Martian regolith to be detrimental to active cells. On the other hand, simply washing the regolith makes it much more hospitable, raising the promise that one day it really could be converted into a soil for growing plants in, producing oxygen and feeding astronauts living on Mars.

The new findings were published in December 2025 in the International Journal of Astrobiology.

President Donald Trump has issued a statement that he will instruct the federal government to begin releasing all of its files related to UFOs, or UAP, as they're now known.

Just days after former president Barack Obama told podcast host Brian Tyler Cohen that he saw "no evidence" of alien life or a conspiracy to hide it while in office, Trump took to social media to make the announcement. "Based on the tremendous interest shown, I will be directing the Secretary of War, and other relevant Departments and Agencies, to begin the process of identifying and releasing Government files related to alien and extraterrestrial life, unidentified aerial phenomena (UAP), and unidentified flying objects (UFOs), and any and all information connected to these highly complex, but extremely interesting and important matters," Trump wrote on his Truth Social platform.

While many believers are hailing the announcement as another step toward disclosure, more skeptical observers point out that this is not the first time Trump has made similar promises, nor is it the first time members of the federal government have called for the release of UFO files specifically. Will this finally be the time we learn what alien skeletons are in the U.S. government's closet? Don't count on it.

The move from Trump follows many of the promises his administration campaigned on, including promising greater transparency from the federal government. Trump's administration has even gone so far as to call itself "the most transparent administration in history" in promotional videos on the White House website.

To that end, Trump has previously promised to release U.S. government files about some of the most conspiracy-theory-laden topics out there. Just last year, for example, Trump issued an executive order calling for the release of all of the files the U.S. government has on the assassinations of President John. F. Kennedy and Dr. Martin Luther King, Jr.

In November 2025, Trump also signed into law the Epstein Files Transparency Act, which called for the release of all unclassified records and documents related to Jeffrey Epstein, the financier indicted in 2019 for child sex trafficking.

But longtime observers point out that those moves by Trump came up short in terms of what was promised.

"Even if an official declassification order is issued regarding UAP/UFOs, what we learn from past releases like the JFK files and, more recently, Department of Justice files related to Jeffrey Epstein, is that much of the documentation will likely be released with significant redactions," Micah Hanks, a longtime researcher into the history of UFOs with relation to the U.S. intelligence community, told Space.com. "Further, some of the documentation may still be withheld altogether, based on national security concerns, which we have also observed in past releases."

The U.S. government has routinely blocked the release of documents, images and videos of alleged or reported UFOs due to the fact that releasing them could reveal sensitive capabilities of satellites, aircraft sensors, or other technologies.

The federal government has also declassified and released large tranches of UFO files before. But none of them contained a "smoking gun" that proved the existence of extraterrestrial visitation or that the U.S. government has concealed an alien presence on Earth.

"While the President's announcement is promising for those who have advocated for broader U.S. government transparency on such issues, it remains to be seen whether anything significant will result from this," Hanks said. "And as past releases have shown, we still have every reason to anticipate that the most sensitive information currently held by the U.S. intelligence community will remain secret."

Other skeptics say there could be an ulterior motive behind Trump's announcement. "I'd be delighted if some interesting UFO files get released, especially if those files contain evidence of aliens. It would be a huge step for science and our understanding of the universe," Mick West, a science writer who has published books on how to debunk sensational claims, told Space.com. "However, I suspect this is largely performative."

West said that leaked UFO videos and other historical documents show little more than ambiguous or misinterpreted data, or even the U.S. government's "embarrassing missteps" into researching pseudoscience or paranormal topics.

But many believers and UAP disclosure proponents remain optimistic.

"It would be fantastic if President Trump could provide us with more details on anomalous objects and how they might related to aliens, and I would be delighted to be involved in any further studies related to this topic," Harvard astronomer Avi Loeb said on his YouTube channel. Loeb has previously claimed that interstellar comet 3I/ATLAS could be an alien spaceship visiting our solar system.

Some members of Congress even took to social media to praise Trump's announcement. Representative Anna Paulina Luna (R-Fla.), who chairs the Task Force on the Declassification of Federal Secrets, thanked Trump in a post on X.

"As the Chairwoman of the Task Force that investigates these subjects, we are incredibly grateful for you doing this! I look forward to going through all the footage, photos, and reports with the public!" Luna wrote. The Florida congresswoman has previously stated that she has been shown evidence of interdimensional beings that can "actually operate through the time spaces that we currently have."

But many critics and skeptics are pointing out the timing of Trump's announcement. It coincides not only with Obama's statement about aliens earlier this week, but also with increased scrutiny on the president due to his former ties with Epstein and his appearance in documents in the U.S. Department of Justice's latest release of files related to the indicted sex trafficker.

One such critic, the comedian and talk show host Seth Meyers, called his shot last year. "We're just one Epstein story away from Trump announcing that UFOs are real," Meyers said in July 2025.

Life on Earth may exist thanks to an incredible stroke of luck — a chemical sweet spot that most planets miss during their formation but ours managed to hit.

A new study shows that Earth formed under an unusually precise set of chemical conditions that allowed it to retain two elements essential for life as we know it: phosphorus and nitrogen. Without a perfect balance of these elements, a rocky planet could appear habitable on the surface yet be fundamentally incapable of supporting biology, according to the study.

"During the formation of a planet's core, there needs to be exactly the right amount of oxygen present so that phosphorus and nitrogen can remain on the surface of the planet," study lead author Craig Walton, of ETH Zurich in Switzerland, said in a statement.

Earth seems to have hit this delicate chemical sweet spot during its formation nearly 4.6 billion years ago, and the new findings could change how scientists search for alien life, the researchers said.

When young planets form, they are often partially or fully molten. As heavy metals sink inward to form a core, lighter materials remain closer to the surface. During this chaotic stage, known as core formation, the amount of oxygen present plays a decisive role in determining where other elements end up — and whether they remain accessible for future life.

The study suggests that oxygen levels must fall within a surprisingly narrow range for both phosphorus and nitrogen to stay in a planet's mantle and crust. Too little oxygen, and phosphorus bonds with iron and is dragged into the core, depriving the surface of a key ingredient for DNA, cell membranes and energy transfer. Too much oxygen, and nitrogen is more easily lost to space. Either way, the chemistry needed for life never fully comes together.

Using models of planetary formation and geochemical behavior, the researchers found that Earth sits squarely inside this narrow range of medium-level oxygen, which they called the chemical Goldilocks zone. Ultimately, our planet retained enough phosphorus and nitrogen to later fuel biology — a result that may be far from common among rocky worlds.

"Our models clearly show that the Earth is precisely within this range," Walton said in the statement. "If we had had just a little more or a little less oxygen during core formation, there would not have been enough phosphorus or nitrogen for the development of life."

Conversely, the researchers also modeled the formation of other planets such as Mars, where oxygen levels were outside this chemical Goldilocks zone. On Mars, for example, the models show more phosphorus in the mantle than on Earth, but less nitrogen, creating challenging conditions for life as we know it, according to the statement.

The findings challenge the traditional focus on the habitable zone, the region around a star where liquid water can exist. While water is critical, the study suggests it may be only part of the story. A planet could orbit at the right distance from its star and still lack the internal chemical inventory required for life to ever emerge.

Crucially, the oxygen conditions that shape this process are linked to the chemical makeup of the host star itself. Because planets form from the same material as their stars, stellar chemistry can hint at whether a system is even capable of producing life-friendly planets in the first place.

If the researchers are right, Earth may be less a cosmic norm and more a fortunate exception — a planet that hit a rare chemical jackpot early on. Using Earth as a benchmark could help scientists zero in on exoplanets that are the most likely to have the perfect balance of elements essential for life.

"This makes searching for life on other planets a lot more specific," Walton said. "We should look for solar systems with stars that resemble our own sun."

Their findings were published Feb. 9 in the journal Nature Astronomy.

NASA's Viking missions to Mars may have discovered evidence for life on the Red Planet after all, according to scientists who are seeking to correct what they believe to be a 50-year-old mistake that has led everybody to think that Mars is lifeless.

Viking 1 and Viking 2 landed on Mars in 1976. On board they carried three life-detection experiments, which produced positive results. But the apparent failure of another instrument, the Gas Chromatograph-Mass Spectrometer (GC-MS), to detect organic molecules necessary for life led Viking Project Scientist Gerald Soffen to conclude, "No bodies, no life."

However, scientists led by Steve Benner, a professor of chemistry at the Foundation for Applied Molecular Evolution in Florida, now argue that the Viking data shows something quite different to what the textbooks say.

"The GC-MS showed an absence of organic molecules, or at least that was the [Viking team's] interpretation," Benner told Space.com. "The problem is that we now know that it did find organic molecules!"

The GC-MS worked by heating samples of Martian dirt — first to 120 degrees Celsius (248 degrees Fahrenheit) to remove any excess carbon dioxide from Mars' atmosphere, and then to 630 degrees C (1,166 degrees F) in order to vaporize any organics present in the dirt so that they could be analyzed by the mass spectrometer.

Puzzlingly, all that the mass spectrometer detected was an unexpected second burst of carbon dioxide and a small quantity of methyl chloride and methylene chloride, when instead there should have been some organic molecules present, if only from meteoritic debris that had built up over billions of years. For there to be none at all, argued the Viking team, required an unknown oxidant. Meanwhile, the carbon dioxide was assumed to have been left over from being observed by the container holding the sample, while methyl chloride was thought to be terrestrial contamination from cleaning solvents originating from the clean room on Earth where the instrument was assembled. This conclusion was bolstered by the fact that, during in-flight tests on the way to Mars, freons such as chlorofluorocarbons that had come from the clean room had been detected.

The problem with that interpretation, according to Benner, is that "methyl chloride is not a cleaning solvent — it's a gas that boils at minus 24 degrees Celsius [minus 191 F]."

Nevertheless, the Viking team claimed that, not only had an oxidant destroyed the organics, but that it could also explain away the other three supposedly positive life detection tests, which measured the apparent metabolization of radioactive carbon, the emission of oxygen and "carbon fixing" (the process by which life turns inorganic carbon into organic compounds). The complication is that, to explain the apparent metabolization of radioactive carbon in the so-called Label Release experiment, the oxidant would have to be very strong. The Viking team concluded that this mystery oxidant was some kind of peroxide, even though peroxides have never been detected on the Red Planet.

This explanation never sat well with some scientists, particularly Gil Levin, who was the lead investigator on the Label Release experiment and who never accepted that his experiment hadn't found life.

But if there is microbial life on Mars, where are the organic molecules? While organic molecules have been found on Mars since by the Curiosity and Perseverance rovers, most of them are believed to originate from abiotic sources, like meteorites, and although Viking had less sensitive mass spectrometers than the modern rovers, it still doesn't explain why Viking saw no organics at all. Benner said that the answer to these puzzling results came in 2008, when NASA's Phoenix lander discovered perchlorate on the Martian surface. Perchlorate is also an oxidant, strong enough to destroy organics from meteorites over the course of millennia, but not strong enough to be the oxidant that the Viking team were looking for to explain the Label Release results.

This misses the point, according to Benner and his colleagues.

"In 2010, Rafael Navarro-González [a NASA astrobiologist who worked on the Curiosity rover mission] showed that organics plus perchlorate produces methyl chloride and carbon dioxide," said Benner.

In fact, the reaction produces 99% carbon dioxide and 1% methyl chloride, which would explain the extra burst of carbon dioxide and the "cleaning solvent" seen when the sample was heated to 630 degrees C.

"So now we know that the GC-MS didn't fail to discover organics — it did discover them, through their degradation products," said Benner.

The detection of organic molecules by GC-MS then strengthens the argument that the three life-detection experiments on the two Viking landers — the Label Release, the Pyrolytic Release and the Gas Exchange experiment — perhaps found life after all, which would remove the need for a strong and undiscovered oxidant.

To this end, Benner and his colleagues have even developed a model for what these purported Martian microbes might be like. They call it the BARSOOM model: Bacterial Autotrophs that Respire with Stored Oxygen On Mars (Barsoom is what the natives of Mars referred to their planet as in the novels of Edgar Rice Burroughs).

Autotrophic bacteria use photosynthesis to produce their own food, only to go dormant at night, storing oxygen that they have created to use when they reawaken. This would explain the emission of oxygen detected by Viking's Gas Exchange experiment.

Benner thinks that the initial misinterpretation of the GC-MS results has set astrobiological research on Mars back 50 years. Instead of a healthy debate about the merits of the Viking evidence for life on Mars, discussion was shut down and the official line ever since, repeated in textbooks, is that the Viking missions found no evidence for life.

To make up for lost time, Benner is now calling for that back-and-forth debate — the very nature of the scientific method — to begin in earnest now, the 50th anniversary year of the Viking 1 and 2 Mars landings.

The conclusions of Benner's team, which also includes Dirk Schulze-Makuch of Technische Universität Berlin and Jan Spacek and Clay Abraham, also of the Foundation for Applied Molecular Evolution, was published last month in the journal Astrobiology.

After years of debate, NASA researchers have zeroed in on the thickness of the Europa's ice shell.

We first discovered that the Jupiter moon's surface looked icy in 1979, when Voyager 2 flew by. Another NASA mission, the Galileo Jupiter orbiter, later confirmed the ice shell while it inspected the giant planet, Europa, and other Jovian moons during the 1990s.

Since then, scientists have been in two camps, championing conflicting theories on the thickness of Europa's ice shell. One theory holds that the shell — which is thought to hide a huge, buried ocean of liquid water — is less than 1 mile (1.6 kilometers) thick, while the other posits that it spans tens of miles.

Now, we appear to have an answer. Using data the Juno Jupiter orbiter gathered in 2022 using its Microwave Radiometer instrument, researchers at NASA's Jet Propulsion Laboratory (JPL) in Southern California calculate that the shell is about 18 miles (28.9 km) thick.

"The 18-mile estimate relates to the cold, rigid, conductive outer layer of a pure water ice shell," Steve Levin, Juno project scientist and co-investigator from JPL, said in a NASA statement on Tuesday (Jan. 27).

"If an inner, slightly warmer convective layer also exists, which is possible, the total ice shell thickness would be even greater," Levin continued. "If the ice shell contains a modest amount of dissolved salt, as suggested by some models, then our estimate of the shell thickness would be reduced by about 3 miles [5 km]."

Understanding the makeup and structure of Europa's icy surface is important, because NASA researchers — and many other scientists around the world — want to find out if the moon hosts alien life. Previous research suggests that the ingredients for life could exist in the moon's subsurface ocean.

"How thick the ice shell is and the existence of cracks or pores within the ice shell are part of the complex puzzle for understanding Europa's potential habitability," Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio, said in the NASA statement.

And a thick ice shell might not be great news for Europa's life-hosting potential. This feature "implies a longer route that oxygen and nutrients would have to travel to connect Europa’s surface with its subsurface ocean," NASA officials wrote in the statement.

This new insight into Europa will provide helpful context for the two spacecraft that are en route to the Jovian system right now. NASA's Europa Clipper should arrive in orbit around Jupiter to investigate Europa's habitability in 2030, and the European Space Agency's Juice (JUpiter ICy moons Explorer) will get there a year later.

The new Europa results were published Dec. 17 in the journal Nature Astronomy.

Scientists argue that limiting the search for life strictly to a star’s traditional habitable zone is too restrictive. That is in light of new climate models, and observations that suggest that liquid water—and therefore potentially life-supporting conditions—can exist well beyond these classical boundaries.

The habitable zone is defined as the region around a star where a planet could maintain liquid water on its surface without turning to ice or gas.

The fact that this water is neither too hot nor too cool has also led to the habitable zone being nicknamed the Goldilocks zone. In our solar system, this zone begins at around the orbit of Venus, the second planet from the sun, past the orbit of Earth, and out to roughly the orbit of Mars.

“[However,] this concept is rooted in the principle that liquid water is necessary for biochemical processes essential to life,” writes a team of researchers in a paper published on Jan. 12 in the Astrophysical Journal. “Although other factors, such as chemical energy sources, elemental diversity, and long-term environmental stability, are also important.”

Using an analytical climate model, the scientists have shown that tidally locked planets—which always show the same face to their star—can maintain liquid water on their permanent night side, even when orbiting much closer to their star than the traditional inner edge of the habitable zone.

“Initially, this configuration raised concerns about extreme temperature gradients and atmospheric collapse on the dark side,” the team writes. “However, 3D climate models have demonstrated that given a sufficient atmospheric pressure, or the presence of an ocean, efficient heat redistribution between the day and night sides can stabilize temperatures and maintain habitable conditions.”

This suggests that for tidally locked planets, common around small M-class and K-class stars, the inner edge of the habitable zone may actually lie closer to the star than in the case of rapidly rotating planets. This extended habitable zone could help explain recent observations made by the James Webb Space Telescope (JWST) of water vapor and other volatile gases in the atmospheres of warm super-Earths closely orbiting their M dwarf stars.

“Signs of water vapor and volatiles have been detected in JWST transmission spectra of small exoplanets,” they write. “Some of these exoplanets are closer to their M dwarf hosts than the inner [habitable zone] boundary […] Water detection on such planets is intriguing, since one would doubt the survival of atmosphere and water under such harsh conditions.”

These findings suggest that such planets can retain significant amounts of water despite lying outside the classical habitable zones—and this doesn’t apply to planets orbiting their stars too closely. The team argues that the habitable zone should be extended in both directions. Even on cold planets far from their stars, liquid water can exist beneath thick ice layers, as subglacial lakes or through internal heating. Similar environments on Earth, such as Antarctica’s subglacial lakes, support microbial life, demonstrating that surface liquid water is not the only possible habitat.

Through a reassessment of habitable zone models and boundary calculations, this study expands the range of worlds considered potentially habitable, revealing new targets in the search for life.

The chemistry that built life on Earth may have begun in deep space, according to a new study. The discovery could help to unravel one of science's central questions: what are the origins of life's molecular building blocks?

Astronomers have detected simple organic molecules drifting through interstellar clouds and preserved in meteorites and comets, indicating that biologically important compounds can form in space and be delivered to planetary surfaces. However, one crucial step has remained unresolved: how amino acids could link together under the harsh conditions of space to form short molecular chains called peptides.

It is these chains of molecules that serve as the first building blocks of proteins, essential for living things.

"We already know from earlier experiments that simple amino acids, like glycine, form in interstellar space. But we were interested in discovering if more complex molecules, like peptides, form naturally on the surface of dust grains before those take part in the formation of stars and planets," research team member and Aarhus University researcher Sergio Ioppolo said in a statement.

Ioppolo and his colleagues demonstrated that peptides can actually form inside icy dust grains exposed to radiation under space-like conditions. In laboratory experiments, they produced glycylglycine—the simplest possible dipeptide—by cooling glycine to cryogenic temperatures, of minus 436 degrees Fahrenheit (minus 260 degrees Celcius), replicating the icy mantles that coat cosmic dust grains, and then bombarding the frozen sample with high-energy protons, a stand-in for cosmic rays.

The results reveal a previously unknown pathway for building protein precursors that does not require liquid water—long thought to be essential—that can operate in the extreme conditions of interstellar space. "All types of amino acids bond into peptides through the same reaction. It is therefore very likely that other peptides naturally form in interstellar space as well," said co-author Alfred Thomas Hopkinson, of Aarhus University. "We haven't looked into this yet, but we are likely to do so in the future."

Alongside glycylglycine, the team observed the formation of both ordinary water and a form of water in which hydrogen atoms are replaced by deuterium, an isotope of hydrogen with an extra neutron, along with a variety of other complex organic molecules.

"We used to think that only very simple molecules could be created in these clouds. The understanding was that more complex molecules formed much later, once the gases had begun coalescing into a disk that eventually becomes a star," Ioppolo explained. "But we have shown that this is clearly not the case."

The results suggest that ionizing radiation supplies enough energy to break and reform chemical bonds, allowing amino acids trapped in ice to link together without liquid water. In effect, cosmic radiation becomes a chemical engine, driving complexity in environments previously thought too cold and inert to support such reactions.

This discovery significantly broadens the range of environments in which life’s precursors might form. Rather than being restricted to warm, wet settings like early Earth’s oceans or hydrothermal vents, peptide synthesis could occur in the cold interstellar medium itself.

"Eventually, these gas clouds collapse into stars and planets. Bit by bit, these tiny building blocks land on rocky planets within a newly formed solar system. If those planets happen to be in the habitable zone, then there is a real probability that life might emerge," Ioppolo explained. "That said, we still don't know exactly how life began. But research like ours shows that many of the complex molecules necessary for life are created naturally in space.

"There's still a lot to be discovered, but our research team is working on answering as many of these basic questions as possible. We've already discovered that many of the building blocks of life are formed out there, and we'll likely find more in the future."

The team's research was published on Jan. 20 in the journal Nature Astronomy.

"Super-Earth" exoplanets may have an in-built way to protect themselves from harmful radiation, giving any potential life on such worlds a better chance of surviving, according to recent research.

Super-Earths, worlds larger than Earth but smaller than Neptune, are among the most commonly detected types of extrasolar planets, or exoplanets, in the Milky Way. Because many have been found within their stars' habitable zones — regions where liquid water could exist and, thus, potentially support life — scientists have increasingly focused on whether these planets can sustain life-friendly conditions over billions of years.

The new study suggests that many super-Earths may be able to generate powerful magnetic fields from molten rock not in their cores, like Earth does, but in a layer sandwiched between the core and mantle.

"A strong magnetic field is very important for life on a planet," study lead Miki Nakajima, an associate professor in the department of Earth and environmental sciences at the University of Rochester in New York, said in a statement. "Super-earths can produce dynamos in their core and/or magma, which can increase their planetary habitability."

The findings, published Jan. 15 in the journal Nature Astronomy, help resolve a long-standing puzzle about how super-Earths might maintain magnetic fields despite interiors whose structures differ from Earth's, the researchers say.

"This paper suggests that, like in many other things, exoplanets might not necessarily follow the solar system paradigm concerning magnetic field generation," Luca Maltagliati, a senior editor at Nature Astronomy, who was not involved with the new study, wrote in a brief piece summarizing the findings. "Planets with masses 3-6 times that of Earth might have their main magnetic field engine not in the core like the Earth but in a layer between the core and mantle."

Long-lived magnetic shields are considered essential for habitability because they help prevent planetary atmospheres from being stripped away by stellar winds and protect surfaces from harmful cosmic and stellar radiation.

Without such protection, even planets located in otherwise favorable habitable zones may struggle to maintain the conditions needed for life, meaning such magma-driven magnetic fields could play a crucial role in making super-Earths habitable across the galaxy.

Earth's magnetic field, which has operated for more than 3 billion years, is generated by the movement of liquid iron in the outer core surrounding a solid inner core. That inner core is critical because it releases heat and lighter elements that keep the molten outer core moving, allowing our planet to sustain its magnetic field.

But larger rocky worlds such as super-Earths are thought to have cores that are either fully solid or fully liquid, which typically limit the operation of a conventional, Earth-like core dynamo.

Nakajima and her team point to an alternative mechanism known as a basal magma ocean (BMO), a layer of molten rock that forms between the core and the mantle. Such layers are thought to arise during planet formation, according to the new study, when repeated large impacts generate global magma oceans that partially crystallize and concentrate iron-rich melt at depth.

The idea of a BMO-driven dynamo was first proposed as a way to explain how Earth may have generated a magnetic field early in its history, before its inner core had formed. Such a layer would have formed following the moon-forming impact, but it likely solidified after roughly 1 billion years, the new study notes.

Super-Earths, by contrast, are larger and experience much higher internal pressures, conditions that could allow basal magma oceans to persist for far longer and sustain magnetic fields over billions of years, the researchers say.

To test whether these deep magma layers could generate magnetic fields, Nakajima and her team conducted shock experiments that compressed rock-forming materials to the extreme pressures expected inside planets several times more massive than Earth. The researchers then combined the lab results with planetary models to determine how massive a super-Earth must be to generate a magnetic field.

They found that under such crushing pressures, iron-rich magma becomes metallic and electrically conductive, suggesting that super-Earths roughly three to six times Earth's mass could maintain BMO-driven magnetic fields for several billion years, longer, and potentially stronger than magnetic fields generated by Earth-like metallic cores alone.

In some cases, the resulting magnetic field at the planet's surface could rival or even exceed Earth's, according to the statement.

"Although detecting the magnetic fields of exoplanets remains challenging," the researchers wrote in the briefing, "it might be possible to observe such strong BMO-driven dynamos in future observations."

This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.

Humans have always been fascinated with space. We frequently question whether we are alone in the universe. If not, what does intelligent life look like? And how would aliens communicate?

The possibility of extraterrestrial life is grounded in scientific evidence. But the distances involved in travel between the stars are vast. If we do contact aliens, it would likely be via long distance communication, with our nearest neighbouring star being 4.4 light years away. Even being optimistic, it would likely take more than ten years for any round-trip communication.

How could that work when we have no shared language? Well, consider how we can engage with creatures here on Earth with minds quite alien to our own: bees.

Despite the vast differences in human and bee brains, both of us can do mathematics. As we argue in a new paper published in the journal Leonardo, our thought experiment lends weight to the idea that mathematics may form the basis for a "universal language," which might one day be used to communicate between the stars.

Mathematics as the language of science

The idea of mathematics as universal is not new. Writing in the 17th century, Galileo Galilei described the universe as a grand book "written in the language of mathematics".

Science fiction, too, has long explored the idea of mathematics as a universal language. In the 1985 novel and 1997 film Contact, extraterrestrials reach out to humans using a repeating sequence of prime numbers sent via radio signal.

In The Three-Body Problem, a novel by Liu Cixin adapted into a Netflix series, communication between aliens and humans to solve a mathematical problem occurs through a video game.

Mathematics also features in a 1998 novella by Ted Chiang called Story of Your Life, which was adapted into the 2016 film Arrival. It describes aliens with a non-linear experience of time and a correspondingly different formulation of mathematics.

Real scientific efforts at universal communication have also involved mathematics and numbers. The covers of the Golden Records, which accompanied the Voyager 1 and 2 space probes launched in 1977, are etched with mathematical and physical quantities to "communicate a story of our world to extraterrestrials".

The 1974 Arecibo radio message beamed out into space consisted of 1,679 zeros and ones, ordered to communicate the numbers one to ten and the atomic numbers of the elements that make up DNA. In 2022, researchers developed a binary language designed to introduce extraterrestrials to human mathematics, chemistry, and biology.

How do we test a universal language without aliens?

A creature with two antennae, six legs, and five eyes may sound like an alien, but it also describes a bee. (Science fiction has of course imagined "insectoid" aliens.)

The ancestors of bees and humans diverged over 600 million years ago, yet we both possess communication, sociality, and some mathematical ability. Since parting ways, both honeybees and humans have independently developed effective, but different, means of communication and cooperation within complex societies.

Humans have developed language. Honeybees evolved the waggle dance – which communicates the location of food sources including distance, direction, angle from the sun, and quality of the resource.

Due to our vast evolutionary separation from bees, as well as the differences between our brain sizes and structures, bees could be considered an insectoid alien model that exists right here on Earth. At least for the purposes of our thought experiment.

Bees and mathematics

In a series of experiments between 2016 and 2024, we explored the ability of bees to learn mathematics. We worked with freely flying honeybees that chose to regularly visit and participate in our outdoor maths tests to receive sugar water.

During the tests, bees showed evidence of solving simple addition and subtraction, categorising quantities as odd or even, and ordering quantities of items, including an understanding of "zero". Bees even demonstrated the ability to link symbols with numbers, in a simple version of how humans learn Arabic and Roman numerals.

Despite the miniature brains of bees, they have demonstrated a rudimentary capacity to perform mathematics and learn to solve problems with quantities. Their mathematical ability involved learning to add and subtract one, which provides a launching pad to more abstract mathematics. The ability to add or subtract by one theoretically allows bees to represent all of the natural numbers.

If two species considered alien to each other – humans and honeybees – can perform mathematics, along with many other animals, then perhaps mathematics could form the basis of a universal language.

If there are extraterrestrial species, and they have sufficiently sophisticated brains, then our work suggests that they may have the capacity to do mathematics. A further question to be answered is whether different species will develop different approaches to mathematics, akin to dialects in language.

Such discoveries would also help to answer the question of whether mathematics is an entirely human construction, or if it is an a consequence of intelligence and thus, universal.

Astronomers at the SETI (Search for Extraterrestrial Intelligence) Institute have learned to read the subtle "twinkle" of a distant cosmic lighthouse, revealing how interstellar space distorts radio signals as they travel across the galaxy.

The research shows that gas between stars can shift the arrival time of a pulsar's signal by mere billionths of a second.

While imperceptible to humans, these tiny delays are significant for experiments that rely on pulsars as ultra-precise cosmic clocks, the researchers say, particularly efforts to detect low-frequency gravitational waves and to search for signs of intelligent life beyond Earth.

"Pulsars are wonderful tools that can teach us much about the universe and our own stellar neighborhood," study lead author Grayce Brown of the SETI Institute said in a statement. "Results like these help not just pulsar science, but other fields of astronomy as well, including SETI."

Beginning in late February 2023, Brown and her team conducted a nearly daily observing campaign lasting 10 months using the SETI-operated Allen Telescope Array in California. The team tracked subtle changes in radio signals from the pulsar PSR J0332+5434 — the fast-spinning remnant of a neutron star located more than 3,000 light-years from Earth and the brightest pulsar visible to the telescope.

From nearly 400 observations, the team identified changes in the pulsar's "twinkling" pattern, known as scintillation, over timescales of hundreds of days. As the radio waves blasted from the pulsar's poles travel through space, they pass through clouds of charged gas, primarily free electrons, that bend, scatter and slightly delay the signal. This interaction produces scintillation, the radio equivalent of how stars appear to twinkle in Earth's atmosphere, according to the study.

As Earth, the pulsar, and the intervening interstellar gas move relative to one another, bright and dim patches form across radio frequencies and evolve over time. These shifting patterns subtly alter when the pulses arrive, introducing timing delays on the order of tens of nanoseconds, the statement says.

Such tiny discrepancies between the predicted and observed arrival times of pulsar pulses can have outsized consequences. Pulsar timing arrays search for low-frequency gravitational waves by looking for correlated deviations in pulse arrival times caused by the stretching and squeezing of spacetime. If delays introduced by interstellar gas are not properly accounted for, they can obscure — or even mimic — the faint signals researchers are trying to detect, the study notes.

Beyond helping to improve pulsar timing, scientists say the findings also provide a valuable tool for SETI researchers working to distinguish genuine cosmic signals from human-made interference. "Noticeable scintillation can help SETI scientists distinguish between human-made radio signals and signals from other star systems," the statement reads.

"We need some way to differentiate between signals coming from Earth and signals coming from beyond our Solar System," Brown told The Debrief. "Because of this research, we know how much scintillation to expect from a radio signal traveling through this pulsar's region of interstellar space."

"If we don't see that scintillation," she added, "then the signal is probably just interference from Earth."

The observations were part of a broader effort that monitored roughly 20 pulsars over about a year, following a pilot phase in late 2022. While the team did not identify a repeating pattern in the scintillation changes, the study notes future observing campaigns lasting longer than a year could further refine predictions and improve corrections for interstellar distortion.

The study was published on Dec. 10, 2025 in The Astrophysical Journal.

Astronomers are using China's powerful FAST radio telescope to chase after 100 intriguing signals detected by the SETI@home project, which is run by SETI (Search for Extraterrestrial Intelligence) scientists.

SETI@home, which ran from 1999 to 2020, had millions of users all around the world donating their CPU time to downloadable software that churned through data collected by the Arecibo radio telescope in Puerto Rico. In the end, 12 billion candidate narrowband signals were spotted. These signals appeared as "momentary blips of energy at a particular frequency coming from a particular point in the sky," David Anderson, a computer scientist at the University of California, Berkeley and co-founder of the SETI@home project, said in a statement.

FAST, the Five-hundred-meter Aperture Spherical Telescope, has been patiently following up on this century of candidate extraterrestrial signals since July 2025. Although observations and analysis are still ongoing, bitter experience has taught the SETI@home team to expect them all to turn out to be local radio frequency interference (RFI) rather than real extraterrestrial beacons.

But whatever their origin, they represent the culmination of one of the largest citizen science projects ever undertaken. It's taken years to figure out how to properly scrutinize this vast amount of data.

"Until about 2016, we didn't really know what we were going to do with these detections that we'd accumulated," said Anderson. "We hadn't figured out how to do the whole second part of the analysis."

"There's no way that you can do a full investigation of every possible signal that you detect, because doing that still requires a person and eyeballs," added Berkeley astronomer Eric Korpela, who co-founded SETI@home along with Anderson and Dan Werthimer, who is an astronomer and electrical engineer also at Berkeley.

Eventually, at the supercomputer facilities of the Max Planck Institute for Gravitational Physics in Germany, algorithms designed to spot RFI sorted the wheat from the chaff, reducing those 12 billion to 1 million, then 1,000. These 1,000 signals then had to be inspected manually, by eye, before being whittled down to 100 that deserved a second look.

Arecibo had been the world's largest single-dish radio telescope, with a 305-meter aperture, until FAST came along in 2016. Because Arecibo collapsed and was destroyed in December 2020, FAST is now the only radio telescope capable of taking on these candidate signals.

"If we don't find ET, what we can say is that we have established a new sensitivity level. If there were a signal above a certain power, we would have found it," said Anderson.

The scale of the project has gone far beyond the dreams of Anderson or anyone on his team when SETI@home began in 1999. They thought they might get 50,000 users if they were lucky. By the end of the first week they had 200,000 users, and within a year they had 2 million.

"I'd say it went way, way beyond our initial expectations," said Anderson.

The data for SETI@home came from piggybacking on Arecibo's regular astronomical observations, and covered billions and billions of stars in the Milky Way.

"We are, without doubt, the most sensitive narrowband search of large portions of the sky, so we had the best chance of finding something," said Korpela. "So yeah, there's a little disappointment that we didn't see anything."

As the mammoth project nears its end, assuming no real extraterrestrial signals turn up in the final 100 candidates, Korpela looks back on the project not just with pride but as a learning experience for future SETI surveys.

"We have to do a better job of measuring what we're excluding," he said. "Are we throwing out the baby with the bath water? I don't think we know for most SETI searches and that is really a lesson for SETI searches everywhere. In a world where I had the money, I would reanalyze it the right way, meaning I'd fix the mistakes that we made. And we did make some mistakes. These were conscious choices because of how fast computers were in 1999."

Indeed, Korpela wonders whether one day a new project could be launched in the same vein as SETI@home to look over all the data again but with modern crowd-sourced computing power and machine learning in search of anything that was missed the first time around.

"There's still the potential that ET is in that data and we missed it just by a hair."

The overall results from SETI@home presented in two papers in 2025 in The Astronomical Journal: one paper on data analysis and findings, and another on data acquisition and processing.

NASA is ramping up its efforts to search for signs of life throughout the universe, and has directed companies to begin developing technologies that will help it do so using the space agency's Habitable Worlds Observatory (HWO) space telescope concept.

Seven companies have been awarded three-year, fixed-price contracts to explore the engineering challenges that need tackling in order to create what will be one of NASA's most powerful telescopes ever. The companies include Astroscale, BAE Systems Space and Mission Systems, Busek, L3Harris, Lockheed Martin, Northrop Grumman and Zecoat.

Each will study ways to fulfill the hardware requirements for HWO, which is being designed to search for signs of life by looking at the light passing through the atmospheres of planets as they orbit stars hundreds and thousands of light-years away. In a Jan. 5 statement announcing the contract selectees, NASA Administrator Jared Isaacman called the project "exactly the kind of bold, forward-leaning science that only NASA can undertake.”

"Humanity is waiting for the breakthroughs this mission is capable of achieving and the questions it could help us answer about life in the universe. We intend to move with urgency, and expedite timelines to the greatest extent possible to bring these discoveries to the world," Isaacman said in the release.

NASA hopes the space telescope can be complete in time to launch by the late 2030s or early 2040s. By then, it will be equipped with technologies that don't yet exist. To fulfill its mission, HWO will need to maintain stability within its optical system capable of functioning within a marginal width the size of a single atom.

The telescope's design, which has not yet been finalized, also calls for a novel coronagraph "thousands of times more capable than any space coronagraph ever built," the release says, to block intrusive peripheral photon sources from distorting images and shade the light from the sun. NASA also wants HWO to be serviceable, so that, in the event of a malfunction or something like a micrometeoroid impact, the space agency can launch repair missions to extend the telescope's life.

"Awards like these are a critical component of our incubator program for future missions, which combines government leadership with commercial innovation to make what is impossible today rapidly implementable in the future," said Shawn Domagal-Goldman, director of NASA's Astrophysics Division in the statement.

By the time its construction is complete, NASA hopes HWO will build upon the scientific and institutional knowledge that came from other flagship space telescope missions, including Hubble, James Webb and the upcoming Nancy Grace Roman Space Telescope, expected to launch later this year.

Europa might not be the best place to look for alien life in the solar system after all.

A new study modeling what the floor of the Jupiter moon's hidden ocean is like concluded that tectonic activity — and the complex chemical reactions that such activity facilitates — is probably negligible.

"Ultimately, without fracturing and faulting, it's not clear to us how fresh rock would be exposed to the ocean to allow for the kinds of continued chemical reactions that microbes would need to sustain themselves," study lead author Paul Byrne, associate professor of Earth, Environmental and Planetary Science at Washington University in St. Louis, told Space.com.

Europa harbors a deep ocean beneath a shell of ice that's dozens of kilometers thick. This ocean wraps around a rocky core, but little is known about the interface between the ocean and the core. If life is to exist in Europa's ocean, it must somehow gain energy, most probably from interactions at the sea floor between water and rock. Access to fresh rock is vital in order to produce more nutrients.

On Earth, tectonic faulting in the seafloor enables water to plunge kilometers down into the rock, and as fresh faults are opened up by shifting tectonic plates, new rock is exposed, maintaining the nutrient supply released into the ocean through hydrothermal vents.

Byrne's team assessed the potential for tectonic activity on Europa's seafloor with a new model that factored in stresses from gravitational tides incurred by Jupiter, the long-term contraction of the moon as its interior gradually cools and the convection of heat energy through the mantle.

However, they found that none of these factors would be strong enough to produce tectonic activity. For example, tidal stresses occur because Europa's orbit around Jupiter is not perfectly circular but rather eccentric, in accordance with Johannes Kepler's first law of orbital motion. This means that, at certain points in each of its 84-hour orbits around Jupiter, Europa is closer to the planet than at other times, and the resulting gravitational differential leads to tides. However, for the tides to be strong enough to induce sufficient tectonic activity, the eccentricity of Europa's orbit would have to be greater — more elongated — than it is (an eccentricity of 0.441 compared to the actual value of 0.009). Even if repeated tidal stresses weaken the uppermost part of Europa's seafloor, creating shallow fractures, they aren't intense enough to extend those faults deep down to new rock.

Similarly, while theoretical models suggest that Europa's rocky core has contracted over billions of years as its interior has cooled, it would have to shrink several kilometers to fracture the bedrock and create deep tectonic faults. This would be more extensive than the process on Earth's moon, which is estimated to have contracted by several tens of meters throughout its four-and-a-half billion-year history, though less than on Mars, which is thought to have contracted by up to 7 kilometers (4.3 miles).

The lack of tectonics is bad news for the possibility of life, since life would need fresh chemical nutrients to survive. One of the main sources of these nutrients on the floor of Earth's oceans is hydrothermal vents, like the famous black smokers. But according to the new modeling, black smokers that billow out hot water filled with nutrients are not possible on Europa.

"But it turns out that there are other kinds of hydrothermal systems," said Byrne. These other kinds percolate through the bedrock to shallower depths and hence are cooler.

"In fact, these other kinds are the most common on Earth," Byrne added. "Such relatively cooler hydrothermal vents could exist on Europa, but they'd be far less energetic than the traditional images we have in our heads when we think about hydrothermal vents. And it's very far from certain how long such cooler hydrothermal systems might last and support chemosynthetic microbial life."

If hydrothermal vents and tectonic faulting are off the menu for Europa, are there any other possible sources of chemical energy and nutrients that could sustain life on the ocean moon? Maybe, said Byrne, but there are still too many unknowns to know for sure. For example, radioactive decay could be a substitute source of energy, but we don't know the numbers for this process on Europa. Alternatively, perhaps nutrients enter the ocean not from below, but from above — meteorites that strike the surface ice and become subsumed and drawn into the ocean. However, it's not clear whether there are routes through the thick ice shell into the ocean and vice versa. This is one of the unknowns that NASA's Europa Clipper mission, currently on its way to Europa, aims to discover.

The findings are also potentially bad news for other ocean moons in the solar system, and Byrne's team is currently preparing a new study that investigates this further.

"Without giving too much away, I can say that the overall findings for Europa are applicable to most other such moons, with the likely exception of [Saturn's moon] Enceladus," Byrne said.

However, despite the pessimistic outlook, Byrne is keen to emphasize that we shouldn't stop looking for life on these icy moons with their hidden oceans.

"We're not saying, and we can't say, that there's no life in Europa," said Byrne. "What we're saying is that it's a harder proposition, based on our results."

The findings were published on Jan. 6 in the journal Nature Communications.

RNA, which is one of life's most crucial molecules dealing with the synthesis of proteins, could be common in the universe, according to a new experiment that shows how RNA could easily have formed on Earth 4.3 billion years ago.

RNA (short for ribonucleic acid) is a simpler cousin of DNA, which is the molecule that contains the genetic information for our cellular biology. RNA comes in a trio of guises. There is messenger RNA (mRNA) that is produced from DNA and contains the genetic instructions for forming proteins. Then there's ribosomal RNA (rRNA) that creates ribosomes vital for producing proteins, and finally transfer RNA (tRNA) that does the actual synthesizing of the proteins from mRNA.

Because it is a simpler molecule than DNA, RNA is thought to have formed first, and thanks to its ability to carry genetic information and create other molecules, RNA has even been heralded as a possible main player in the story of the origin of life on Earth in a hypothesis colloquially known as "RNA world." In this scenario, the first single-celled lifeforms would have used RNA rather than DNA for self-replicating and copying their genetic information.

Understanding how RNA formed has, however, been challenging. What prompted RNA's ingredients to come together just so and undergo the correct series of chemical reactions? On the face of it, the odds of RNA forming just by chance seem astronomical.

So chemists look for pathways that could inevitably lead to the formation of molecules like RNA. One pathway is known as the six-step Discontinuous Synthesis Model (DSM).

However, one of the stumbling blocks on this pathway is borate, which is a family of common compounds found in seawater. Borates are oxyanions; if ions are atoms or molecules that have a positive electrical charge, then anions have an overall negative electrical charge. Further, borates contain atoms of both boron and oxygen. The problem is that it had been thought that borates hinder some of the reactions on the chemical pathway to RNA.

Now, a team of biochemists led by Yuta Hirakawa of Tohoku University in Japan and the Foundation for Applied Molecular Evolution in Florida say that chemists have been getting it wrong and that borates are actually beneficial to the formation of RNA.

Hirakawa's team performed experiments in which they added the ingredients of RNA — the five-carbon sugar ribose, phosphates and the four nucleobases used by RNA (adenine, guanine, cytosine and uracil) — to a mixture that also included borates and basalt. They then heated the mixture and allowed it to dry out, mimicking conditions that they argue would have been common around underground aquifers on the early Earth.

What they found was that RNA had formed in the mixture. Furthermore, the borates hadn't hindered anything at all, but actually supported some of the steps in the DSM model, such as stabilizing the ribose molecules that can often be unstable and break down, and facilitating the production of phosphates.

These findings have also been bolstered by new discoveries about the sample of material brought to Earth from the asteroid Bennu by NASA's OSIRIS-REx mission. In particular, with the recent announcement of the discovery or ribose in the Bennu sample, all the ingredients of RNA have now been identified in the 120 grams (4.2 ounces) of dirt and stones that OSIRIS-REx delivered to Earth from Bennu.

Hirakawa's team envisage that the impact of a 500-kilometer-wide (310 miles) protoplanet, similar in size to the asteroid Vesta and loaded with RNA's ingredients, could have brought RNA's building blocks to our planet en masse. They estimate that this impact, and the production of RNA, would have taken place 4.3 billion years ago, 200 million years after Earth's birth and 200 million years before the oldest evidence for life on Earth yet found, in isotopes of carbon found in 4.1-billion-year-old deposits of the mineral zircon.

Previously, RNA had only been formed in a laboratory through human intervention to deliberately trigger chemical reactions. Hirakawa's team argue that their research is the first time that RNA has been produced in the lab without humans getting involved, although critics argue that even the act of putting all the building blocks of RNA together in a test tube is a human intervention.

Impacts with large asteroids also occurred in the early days of Mars' history, meaning that the building blocks of RNA would also have been delivered to the Red Planet. Intriguingly, borates have also been detected on Mars, meaning everything should have been in place to produce RNA there too.

Although RNA is not life, RNA is essential to almost all life that we know of. If RNA did form on Earth quickly, geologically speaking, then it could have provided a shortcut to the first simple organisms to arise on our planet.

The research was published on Dec. 15 in the journal Proceedings of the National Academy of Sciences.

This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.

When NASA scientists opened the sample return canister from the OSIRIS-REx asteroid sample mission in late 2023, they found something astonishing.

Dust and rock collected from the asteroid Bennu contained many of life's building blocks, including all five nucleobases used in DNA and RNA, 14 of the 20 amino acids found in proteins, and a rich collection of other organic molecules. These are built primarily from carbon and hydrogen, and they often form the backbone of life's chemistry.

For decades, scientists have predicted that early asteroids may have delivered the ingredients of life to Earth, and these findings seemed like promising evidence.

Even more surprising, these amino acids from Bennu were split almost evenly between "left-handed" and "right-handed" forms. Amino acids come in two mirror-image configurations, just like our left and right hands, called chiral forms.

On Earth, almost all biology requires the left-handed versions. If scientists had found a strong left-handed excess in Bennu, it would have suggested that life's molecular asymmetry might have been inherited directly from space. Instead, the near-equal mixture points to a different story: Life's left-handed preference likely emerged later, through processes on Earth, rather than being pre-imprinted in the material delivered by asteroids.

If space rocks can carry familiar ingredients but not the chemical "signature" that life leaves behind, then identifying the true signs of biology becomes extremely complicated.

These discoveries raise a deeper question – one that becomes more urgent as new missions target Mars, the Martian moons and the ocean worlds of our solar system: How do researchers detect life when the chemistry alone begins to look "lifelike"? If nonliving materials can produce rich, organized mixtures of organic molecules, then the traditional signs we use to recognize biology may no longer be enough.

As a computational scientist studying biological signatures, I face this challenge directly. In my astrobiology work, I ask how to determine whether a collection of molecules was formed by complex geochemistry or by extraterrestrial biology, when exploring other planets.

In a new study in the journal PNAS Nexus, my colleagues and I developed a framework called LifeTracer to help answer this question. Instead of searching for a single molecule or structure that proves the presence of biology, we attempted to classify how likely mixtures of compounds preserved in rocks and meteorites were to contain traces of life by examining the full chemical patterns they contain.

Identifying potential biosignatures

The key idea behind our framework is that life produces molecules with purpose, while nonliving chemistry does not. Cells must store energy, build membranes and transmit information. Abiotic chemistry produced by nonliving chemical processes, even when abundant, follows different rules because it is not shaped by metabolism or evolution.

Traditional biosignature approaches focus on searching for specific compounds, such as certain amino acids or lipid structures, or for chiral preferences, like left-handedness.

These signals can be powerful, but they are based entirely on the molecular patterns used by life on Earth. If we assume that alien life uses the same chemistry, we risk missing biology that is similar – but not identical – to our own, or misidentifying nonliving chemistry as a sign of life.

The Bennu results highlight this problem. The asteroid sample contained molecules familiar to life, yet nothing within it appears to have been alive.

To reduce the risk of assuming these molecules indicate life, we assembled a unique dataset of organic materials right at the dividing line between life and nonlife. We used samples from eight carbon-rich meteorites that preserve abiotic chemistry from the early solar system, as well as 10 samples of soils and sedimentary materials from Earth, containing the degraded remnants of biological molecules from past or present life. Each sample contained tens of thousands of organic molecules, many present in low abundance and many whose structures could not be fully identified.

At NASA's Goddard Space Flight Center, our team of scientists crushed each sample, added solvent and heated it to extract the organics — this process is like brewing tea. Then, we took the "tea" containing the extracted organics and passed it through two filtering columns that separated the complex mixture of organic molecules. Then, the organics were pushed into a chamber where we bombarded them with electrons until they broke into smaller fragments.

Traditionally, chemists use these mass fragments as puzzle pieces to reconstruct each molecular structure, but having tens of thousands of compounds in each sample presented a challenge.

LifeTracer

LifeTracer is a unique approach for data analysis: It works by taking in the fragmented puzzle pieces and analyzing them to find specific patterns, rather than reconstructing each structure.

It characterizes those puzzle pieces by their mass and two other chemical properties and then organizes them into a large matrix describing the set of molecules present in each sample. It then trains a machine learning model to distinguish between the meteorites and the terrestrial materials from Earth's surface, based on the type of molecules present in each.

One of the most common forms of machine learning is called supervised learning. It works by taking many input and output pairs as examples and learns a rule to go from input to output. Even with only 18 samples as those examples, LifeTracer performed remarkably well. It consistently separated abiotic from biotic origins.

What mattered most to LifeTracer was not the presence of a specific molecule but the overall distribution of chemical fingerprints found in each sample. Meteorite samples tended to contain more volatile compounds – they evaporate or break apart more easily – which reflected the type of chemistry most common in the cold environment of space.

Some types of molecules, called polycyclic aromatic hydrocarbons, were present in both groups, but they had distinctive structural differences that the model could parse. A sulfur-containing compound, 1,2,4-trithiolane, emerged as a strong marker for abiotic samples, while terrestrial materials contained products formed through biological process.

These discoveries suggest that the contrast between life and nonlife is not defined by a single chemical clue but by how an entire suite of organic molecules is organized. By focusing on patterns rather than assumptions about which molecules life "should" use, approaches like LifeTracer open up new possibilities for evaluating samples returned from missions to Mars, its moons Phobos and Deimos, Jupiter's moon Europa and Saturn's moon Enceladus.

Future samples will likely contain mixtures of organics from multiple sources, some biological and some not. Instead of relying only on a few familiar molecules, we can now assess whether the whole chemical landscape looks more like biology or random geochemistry.

LifeTracer is not a universal life detector. Rather, it provides a foundation for interpreting complex organic mixtures. The Bennu findings remind us that life-friendly chemistry may be widespread across the solar system, but that chemistry alone does not equal biology.

To tell the difference, scientists will need all the tools we can build — not only better spacecraft and instruments, but also smarter ways to read the stories written in the molecules they bring home.

After years of making headlines, air vehicles of nameless origin, unknown intent, and seemingly odd capabilities are still being reported within America's national airspace, allegedly flying over sensitive facilities and interfering with commercial air traffic.

All of this aerial weirdness involves unidentified anomalous phenomena, or UAP for short. Whatever they are, UAP continue to be seen, reported and even documented through various sensor technologies. However, despite years of whistleblowers testifying before Congress, there seems to have been a bottleneck in getting to the bottom of the UAP issue in 2025. Why so?

Key specialists appraising the issue UAP have yet to untangle the mystery, but do appear to agree on what needs to be done now to further resolve what UAP are and from where they might originate.

Plurality of minds

The UAP phenomenon benefits from having a plurality of minds engaged in disciplined debate, suggests Michael Cifone, founding executive director and President of the Society for UAP Studies, based in Los Angeles, California.

Today, there's a division emerging between classical Unidentified Flying Object (UFO), aka "flying saucer," incidents and studying UAP from the point of view of observational and experimental science. But engaging scientific methods and instruments turns out to be neither trivial nor cheap, Cifone said.

"Perhaps the holdup is reluctance to dump time, energy and money into what looks to some like a wild goose chase," said Cifone.

Cold cases

"Like any other scientific venture, both funding and institutional support is required," Cifone said. "Given the historical stigma associated with the topic that has been hard to achieve. But now with the emphasis no longer on chasing forensic cold cases, and relying on reports of UAP, serious scientists and student researchers are getting involved."

The upshot is to deploy scientific methodology to establish the observational framework with the proper instrumentation, Cifone added, "in order to generate the data on UAP from which more secure conclusions can be derived."

Cifone said that progress, like in any other science or research area, will be slow but hopefully steady, albeit incremental.

"What will likely happen is that there will be downstream benefits that aren't foreseeable exactly now. Maybe new sciences will break away. So it will be a win for the growth of knowledge and for science in particular," Cifone senses.

For Cifone, his view is to keep the eye on the ball and work out the observational framework design and required instruments and observational modalities before we can have the reliable datasets we need. "But science doesn't always go as planned. In any case, there's a lot of work to be done."

Cifone points to an increasing number of institutions that are studying UAPs. Indeed, work underway on UAP has blossomed into a world-wide field of research, he said.

All sky, all the time

To Cifone's point, there's the University of Würzburg in northern Bavaria, one of the oldest universities in Germany. An Interdisciplinary Research Center for Extraterrestrial Studies (IFEX) has been established.

One effort the university is developing is an "AllSkyCAM" able to capture UAP. An automated reporting system is currently under construction with the university cooperating with the Luftfahrt-Bundesamt, the national civil aviation authority of Germany, to research unusual phenomena in the country's airspace.

Then there's the Galileo Project led by astrophysicist Avi Loeb of Harvard University. They have designed and built an array of sensors to scan the sky for aerial phenomena and assess atmospheric anomalies that may not be of terrestrial origin.

This type of research can produce data on UAP, Cifone said, "then we need to experiment with the data and produce theories, or what you call explanations, and perhaps even understanding! We're only at the observational framework design and testing phase. Then we need to let the systems run, probably for many years."

Test a hypothesis

There's need to be able to scientifically test a hypothesis that some UAP are potentially extraterrestrial craft, said Robert Powell, executive board member of the Scientific Coalition for UAP Studies (SCU).

"I consider extreme acceleration to be the best characteristic that has the potential to eliminate a terrestrial explanation for a UAP," said Powell. But measurement of high accelerations of UAP, he said, requires high-precision scientific gear and data.

"The cost of putting out a network of calibrated and characterized equipment, maintaining it, obtaining placement rights on land, and analyzing the data will cost tens to hundreds of millions of dollars," said Powell.

Military systems

One estimate by an engineer in SCU forecasts that given 300 "actual" UAP sightings per year — and assuming random distribution of sightings — that with 930 automated camera systems distributed across the U.S., one would have a 95% chance of detecting a UAP of 50 foot or larger size within a year.

"To date, the financial resources to achieve this are not available," said Powell. "The military has the capability with radar, satellite, and optical systems, but the scientific community does not have access to these systems." He thinks the work ahead could be done now via military systems, but only if there were no national security concerns.

"I think it will take many years to do it through privately-financed civilian systems but that doesn't mean we shouldn't continue working at it," Powell concluded.

Ignore, rationalize away

Ryan Graves is chair of the American Institute of Aeronautics and Astronautics (AIAA) Unidentified Anomalous Phenomena Integration Committee. He is also director of Americans for Safe Aerospace, a military pilot group devoted to aerospace safety and national security, but focused on UAPs.

"Highly credible people and professional observers are seeing objects that appear to exhibit capabilities beyond the state of the art," Graves told Space.com. "In the data received, there seems to be this core anomalous aspect that we can't just ignore or rationalize away."

Graves speaks with UAP eye-witness authority as a former Lt. U.S. Navy and F/A-18F pilot. He was the first active-duty pilot to publicly point to his own encounters and spotlights his military colleagues regarding their UAP sightings.

In July 2023, Graves testified about UAPs before the House Oversight Committee's National Security Subcommittee in Congress, a hearing centered on UAP and the implications for national security, public safety, and how best to attain government transparency on the issue.

Pay attention

"We need to pay attention to this and recognize the national security implications," Graves said. Objects are operating in sovereign air space, he said, potentially collecting intelligence and trying to break into or set the stage to counter our defenses and set the country up for strategic surprise.

In blunt talk, Graves said UAP are engaged in actions "that would be recognized as acts of war or at the minimum preparation for an attack."

For its part, the AIAA UAP Integration & Outreach Committee is a strictly agnostic, science-first committee inside the AIAA.

"Our remit is to bring aerospace rigor to an area with real safety-of-flight implications," Graves said. The committee has been convening experts across AIAA's technical committees, publishing peer-reviewed and conference papers, and producing policy guidance that standardizes how aviation professionals document and share safety-relevant observations, Graves added.

Retention of data

While AIAA provides technical expertise rather than lobbying, Graves said the work on UAP has helped clarify best-practice reporting standards as well as set standards for retention of data on what's being reported.

One early payoff is that AIAA's UAP effort parallels what Congress has been considering in the standalone bill "Safe Airspace for Americans Act," introduced in January 2024 and reintroduced in September of this year. "Our focus remains the same," said Graves, "and that is credible data, clear procedures, and aviation safety."

That bipartisan Act is championed by U.S. representatives Robert Garcia of California and Glenn Grothman of Wisconsin, legislation crafted to support civilian UAP reporting.

"Transparency surrounding UAP is crucial for national security, public safety, and making sure people trust that our government is taking these reports seriously," Congressman Garcia said in a statement. "This bill creates a clear, protected pathway for pilots and other aviation professionals to report UAP incidents without having to fear stigma or worry about retaliation. This is a vital step forward to make sure our skies are safe and our government is responsive."

Closure on the topic?

Graves also points to the current leadership of the Department of Defense All-domain Anomaly Resolution Office, or AARO. It too is established to minimize technical and intelligence surprise by "synchronizing identification, attribution, and mitigation of UAP in the vicinity of national security areas," the AARO states.

"I'm optimistic. There is significant organizational change across the government that I think will bare fruit. There process is maturing to the point where they can start delivering on their expectations," said Graves.

Overall, Graves is heartened by current UAP interest and on-going activities.

"I don't know if there's been a better time to hope for closure on this topic. I don't think we've ever been in quite the situation we're in today," Graves said.

Saturn's huge moon Titan may not hide an ocean under its frozen surface but rather widespread pockets of liquid water, a new study finds.

Titan is the largest of the 274 known moons orbiting Saturn. In fact, Titan is bigger than the planet Mercury.

"I love Titan — I think it's one of the most interesting worlds in the solar system," study lead author Flavio Petricca, a planetary scientist at NASA's Jet Propulsion Laboratory in Southern California, told Space.com. "It's the only moon in our solar system with an atmosphere, and it's the only body with liquid on its surface other than Earth."

Scientists have long suspected that seas might also lurk under Titan's icy shell. For instance, the way Titan flexes under Saturn's gravity suggests that the moon is home to a vast underground ocean.

In the new study, Petricca and his colleagues wanted to reexamine Titan using new, improved methods to analyze radio tracking data. These new techniques greatly reduced uncertainties regarding data gathered by NASA's Cassini mission of Titan's interior.

Unexpectedly, the scientists discovered that Titan's interior is resisting distortion from Saturn's gravitational pull to a much greater degree than previously thought. This suggests Titan likely does not have a hidden ocean, but instead a layer of ice close to its melting point that is kept from liquefying by high pressure. This slushy icy likely hosts pockets of liquid water, the researchers added.

Titan may once have had an underground ocean near the beginning of its history, Petricca said. There may not have been enough heat from radioactive elements in its core to keep this ocean from freezing, he noted. "It may be going through a phase again where heating is increasing again," Petricca added.

All in all, ocean worlds may be less common than recently thought, the scientists noted. "We're not certain if having widespread liquid pockets instead of a global ocean makes Titan more or less habitable," Petricca said. "It will be interesting to find out."

NASA's upcoming Dragonfly mission to Titan can help scan the moon to better understand its geology. "We'll better understand the conditions for habitability there," Petricca said.

The scientists detailed their findings online Dec. 17 in the journal Nature.

Astronomers using the James Webb Space Telescope (JWST) say they have found the strongest evidence yet for an atmosphere around a rocky world outside our solar system.

The findings challenge the prevailing wisdom that relatively small planets orbiting extremely close to their stars cannot sustain atmospheres.

The ultra-hot super-Earth, TOI-561 b, is the innermost of at least three planets circling a 10-billion-year-old star located about 280 light-years from Earth. The planet orbits at just one-fortieth the distance between Mercury and the sun, completing a full orbit in under 11 hours.

That extreme proximity places it in a class of ultra-short-period super-Earths that are heated to temperatures high enough to melt rock. Under such conditions, scientists generally expect planets to lose any atmosphere due to intense stellar radiation, leaving behind bare, airless rock. But observations from NASA's TESS space telescope have shown TOI-561 b has an unusually low density for a purely rocky world, suggesting that another explanation may be needed.

"It must have formed in a very different chemical environment from planets in our own solar system," Johanna Teske, a staff scientist at the Carnegie Earth and Planets Lab in Washington D.C. who led the new paper, said in a statement.

To test whether the planet has an atmosphere, the team used the JWST's NIRSpec instrument to measure the temperature of TOI-561 b's dayside. In May 2024, JWST observed the planet–star system continuously for more than 37 hours, capturing four full orbits. Scientists focused on moments when the planet passed behind its star, events known as "secondary eclipses" when the planet's own light briefly disappeared. By measuring the tiny drop in the system's total brightness during each eclipse, the team could isolate the planet's infrared glow and directly determine its dayside temperature.

If TOI-561 b had no atmosphere, its dayside should reach roughly 4,900 degrees Fahrenheit (2,700 degrees Celsius). Instead, the JWST measured a temperature much cooler, around 3,100 degrees Fahrenheit (1,700 degrees Celsius). To understand why, the researchers tested a range of possible surfaces and atmospheric types to see which could reproduce the signal observed by JWST.

"We really need a thick volatile-rich atmosphere to explain all the observations," study co-author Anjali Piette of the University of Birmingham said in the statement. "Strong winds would cool the dayside by transporting heat over to the nightside."

The team suggests the planet may maintain a balance between its molten surface and its atmosphere, allowing gases to cycle between them and potentially replenishing its atmosphere.

"While gases are coming out of the planet to feed the atmosphere, the magma ocean is sucking them back into the interior," study co-author Tim Lichtenberg of the University of Groningen in the Netherlands said in the statement. "It's really like a wet lava ball."

The results open the door to probe the interiors and geological activity of such extremely hot rocky planets by studying their atmospheres, the researchers note.

The findings were published on Dec. 11 in the The Astrophysical Journal Letters.

The first astronauts to set foot on Mars should hunt for signs of past or present Red Planet life.

That's the overarching conclusion of an in-depth report about human Mars exploration from the U.S. National Academies of Sciences, Engineering and Medicine that came out today (Dec. 9).

"The detection of life on Mars is a persistent top priority for explorers of many disciplines, and it is the top science objective in this report," states the 240-page document, which is called "A Science Strategy for the Human Exploration of Mars."

The National Academies prepared the report for NASA, which wants to send astronauts to the Red Planet as soon as the mid-2030s. The document offers recommendations for how the agency can maximize the science gains of its planned crewed Mars campaign.

Those recommendations are extensive and detailed. For example, the report lays out 11 science objectives that such a campaign should pursue, with the search for signs of life (as well as indications of "indigenous prebiotic chemistry" and a broad assessment of habitability) at the top of the list.

The other 10 objectives, listed in order of descending priority, are:

• Characterize Mars' water and carbon dioxide cycles
• Map Martian geology in detail
• Determine how the Martian environment affects the physical and psychological health of astronaut explorers
• Figure out what starts and drives Martian dust storms
• Determine the availability and accessibility of Martian resources that could "support permanent habitation"
• Discover if exposure to the Martian environment affects DNA and reproduction
• Learn about the population dynamics of microbes on Mars, and if microbial species from Earth could adversely affect astronauts' health and performance on the Red Planet
• Determine how Martian dust affects astronauts and their hardware
• Learn how the Martian environment affects a transplanted ecosystem of Earth microbes, plants and animals
• Gain a better understanding of the Martian radiation environment and how it may affect crewmembers and their missions

"A Science Strategy for the Human Exploration of Mars" also proposes four possible three-mission campaigns, the top-ranked of which could achieve all 11 of the above objectives.

That campaign would send all three missions to "a low- to mid-latitude site with near-surface glacier ice and diverse geology," the report states. "The search for prebiotic chemistry and life would focus on near-surface niche environments, such as geologically recent transiently habitable zones, and/or ice, including layered ice."

Another possible campaign would target the deep subsurface, establishing a powerful drilling operation that could get 1.2 to 3 miles (2 to 5 kilometers) beneath the red dirt, where pockets of liquid water are thought to exist.

Both of those proposed campaigns would feature an initial 30-sol crewed surface mission, an uncrewed cargo delivery flight and then a 300-sol astronaut mission on the surface. (One sol, or Martian day, is slightly longer than an Earth day — about 24 hours and 40 minutes.) So would a third proposed campaign, though a fourth would launch three crewed 30-sol missions to three different sites on the Red Planet.

There is some commonality across all the proposed campaigns. For example, according to the report, no matter how NASA's crewed Mars plans take shape, the agency should aim to build a science lab on the Red Planet's surface, haul Mars samples home from every astronaut mission and set up a recurring "Mars Human-Agent Teaming Summit" to maximize and coordinate the efforts of robotic missions, astronauts and artificial intelligence.

In addition, the report notes, a concerted search for Mars life will be constrained by current "planetary protection" guidelines, which aim to minimize the chances that our exploration efforts contaminate other worlds with Earth microbes or bring alien life to our shores.

Therefore, the document states, "NASA should continue to collaborate on the evolution of planetary protection guidelines, with the goal of enabling human explorers to perform research in regions that could possibly support, or even harbor, life."

New observations of one of the famous TRAPPIST-1 planets are once again teasing scientists with tantalizing clues about a world that may — or may not — harbor an atmosphere capable of sustaining life-friendly liquid water.

TRAPPIST-1e is one of seven Earth-size exoplanets tightly packed around a cool red dwarf star smaller and dimmer than our sun that's about 40 light-years away. It orbits in the system's "habitable zone," where temperatures could allow liquid water to exist — but that's only if the planet has an atmosphere. Early James Webb Space Telescope (JWST) observations even hinted at a possible atmosphere, revealing faint signatures of methane, which, on Earth, results from living organisms and is tied to complex chemistry on Saturn's haze-shrouded moon Titan.

But those first glimmers, scientists now say, were likely misleading.

"Based on our most recent work, we suggest that the previously reported tentative hint of an atmosphere is more likely to be 'noise' from the host star," Sukrit Ranjan, an assistant professor at the University of Arizona Lunar and Planetary Laboratory, said in a statement. "However, this does not mean that TRAPPIST-1e does not have an atmosphere — we just need more data."

The new paper uses detailed computer simulations to test whether TRAPPIST-1e could realistically maintain a methane-rich, Titan-like atmosphere. The results suggest methane on a world orbiting a small, active red dwarf star like TRAPPIST-1 would be destroyed much faster than on Titan — too quickly for any plausible geological process to replenish it.

The latest findings build on two papers published in September that analyzed the JWST's 2023 observations of TRAPPIST-1e. During four separate transits when the planet crossed the face of its star, the JWST's Near-Infrared Spectrograph (NIRSpec) instrument recorded subtle changes in starlight that could, in principle, reveal atmospheric chemicals. The data were consistent with an atmosphere dominated by nitrogen and methane and lacking carbon dioxide, effectively ruling out a Venus- or Mars-like atmosphere.

But the signals varied significantly from transit to transit, hinting that the measurements were being contaminated by the star itself. TRAPPIST-1 is smaller, cooler and far dimmer than our sun, cool enough that gas molecules, including methane, can form in the star's own atmosphere.

"We reported hints of methane, but the question is, 'is the methane attributable to molecules in the atmosphere of the planet or in the host star?'" Ranjan said in the statement.

In the paper, Ranjan and his team modeled how long methane could realistically survive in TRAPPIST-1e's environment. They found that while Titan's methane can persist for 10 million to 100 million years, methane on TRAPPIST-1e would last only about 200,000 years. The planet receives far more ultraviolet radiation than Titan, causing methane to be broken apart thousands of times faster, the study notes.

That makes it extraordinarily unlikely that scientists would catch the planet during a methane-rich phase unless methane were being replenished at extreme, continuous rates, the researchers say. Maintaining Titan-like levels would require TRAPPIST-1e to outproduce Titan in methane generation, an implausible scenario that would demand nonstop global volcanism, catastrophic methane release from an icy interior, or constant planetary resurfacing. Even under generous assumptions, these processes cannot fully account for the required methane supply, the study notes.

As a result, the team concludes that more rigorous analysis and additional observations are needed to determine whether TRAPPIST-1e has any atmosphere at all, and whether the JWST's tentative methane hints originate from the planet or are simply artifacts of the star.

"The basic thesis for TRAPPIST-1e is this: If it has an atmosphere, it's habitable," Ranjan said in the statement. "But right now, the first-order question must be, 'Does an atmosphere even exist?'"

Despite the challenges, TRAPPIST-1e remains one of the most promising potentially habitable worlds beyond our solar system. However, JWST, designed before the first exoplanet was discovered, is operating at the limits of its sensitivity when probing the atmospheres of Earth-sized planets.

Future instruments may help disentangle the confusing signals. NASA's upcoming Pandora mission, scheduled for launch in 2026, will observe stars and planets simultaneously to better separate stellar and atmospheric features.

The researchers are also planning a rare dual-transit observation in which TRAPPIST-1e and the innermost planet TRAPPIST-1b cross the star together. TRAPPIST-1b is known to lack an atmosphere, so comparing its "clean" signal to TRAPPIST-1e's could reveal which features belong to the star and which — if any — arise from TRAPPIST-1e's atmosphere, scientists say.

"These observations will allow us to separate what the star is doing from what is going on in the planet's atmosphere — should it have one," said Ranjan.

The paper about these results was published on Nov. 3 in The Astrophysical Journal Letters.

Frequent flares from the nearby star TRAPPIST-1 could offer new clues in the search for habitable planets beyond Earth.

TRAPPIST-1 is an ultracool red dwarf, located about 40 light-years away in the constellation Aquarius. It hosts seven Earth-size planets, three of which orbit in the so-called "habitable zone" where liquid water might exist. However, the small star is notoriously active, erupting with energy bursts roughly six times per day, which can threaten planetary atmospheres within the system and obstruct observations, according to a statement from the University of Colorado Boulder.

Using data from the James Webb Space Telescope (JWST), researchers tracked six flares observed in 2022 and 2023. These flares appear as a big flash detectable by the JWST's infrared sensors, revealing how much heat the star releases during an outburst. By combining these observations with computer simulations, the team reconstructed the physical processes driving each flare, allowing them to estimate the properties of the electron beams that trigger these stellar tantrums.

"If we can simulate these events using a computer model, we can reverse engineer how a flare might influence the radiation environment around each of these planets," Ward Howard, lead author of the study, said in the statement. This, in turn, can help determine which worlds might retain atmospheres capable of supporting life.

Surprisingly, the electron beams powering these flares appear about ten times weaker than those seen in similar stars. That doesn't mean they're harmless — each flare emits radiation across the spectrum, from visible light to ultraviolet radiation and powerful X-rays, all of which can erode or alter planetary atmospheres over time.

As a result, the researchers suggested that the innermost TRAPPIST-1 planets may have lost their atmospheres, potentially leaving them as bare rocks, while one planet in the habitable zone, TRAPPIST-1e, could still retain a thin, Earth-like atmosphere — a tentative sign that it might support conditions favorable to life.

By decoding TRAPPIST-1's flare behavior, scientists can refine predictions about which planetary atmospheres might survive its constant outbursts. Rather than mere observational nuisances or purely destructive forces, these eruptions can be read as messages from the star, offering key insights into the potential habitability of its planets and informing the broader search for life beyond Earth.

Their findings were published Nov. 20 in the Astrophysical Journal Letters.

This article was originally published at The Conversation. The publication contributed the article to Space.com's Expert Voices: Op-Ed & Insights.

When astronomers search for planets that could host liquid water on their surface, they start by looking at a star's habitable zone. Water is a key ingredient for life, and on a planet too close to its star, water on its surface may "boil"; too far, and it could freeze. This zone marks the region in between.

But being in this sweet spot doesn't automatically mean a planet is hospitable to life. Other factors, like whether a planet is geologically active or has processes that regulate gases in its atmosphere, play a role.

The habitable zone provides a useful guide to search for signs of life on exoplanets – planets outside our solar system orbiting other stars. But what's in these planets' atmospheres holds the next clue about whether liquid water — and possibly life — exists beyond Earth.

On Earth, the greenhouse effect, caused by gases like carbon dioxide and water vapor, keeps the planet warm enough for liquid water and life as we know it. Without an atmosphere, Earth's surface temperature would average around zero degrees Fahrenheit (minus 18 degrees Celsius), far below the freezing point of water.

The boundaries of the habitable zone are defined by how much of a "greenhouse effect" is necessary to maintain the surface temperatures that allow for liquid water to persist. It's a balance between sunlight and atmospheric warming.

Many planetary scientists, including me, are seeking to understand if the processes responsible for regulating Earth's climate are operating on other habitable zone worlds. We use what we know about Earth’s geology and climate to predict how these processes might appear elsewhere, which is where my geoscience expertise comes in.

Why the habitable zone?

The habitable zone is a simple and powerful idea, and for good reason. It provides a starting point, directing astronomers to where they might expect to find planets with liquid water, without needing to know every detail about the planet's atmosphere or history.

Its definition is partially informed by what scientists know about Earth's rocky neighbors. Mars, which lies just outside the outer edge of the habitable zone, shows clear evidence of ancient rivers and lakes where liquid water once flowed.

Similarly, Venus is currently too close to the sun to be within the habitable zone. Yet, some geochemical evidence and modeling studies suggest Venus may have had water in its past, though how much and for how long remains uncertain.

These examples show that while the habitable zone is not a perfect predictor of habitability, it provides a useful starting point.

Planetary processes can inform habitability

What the habitable zone doesn't do is determine whether a planet can sustain habitable conditions over long periods of time. On Earth, a stable climate allowed life to emerge and persist. Liquid water could remain on the surface, giving slow chemical reactions enough time to build the molecules of life and let early ecosystems develop resilience to change, which reinforced habitability.

Life emerged on Earth, but continued to reshape the environments it evolved in, making them more conducive to life.

This stability likely unfolded over hundreds of millions of years, as the planets surface, oceans and atmosphere worked together as part of a slow but powerful system to regulate Earth’s temperature.

A key part of this system is how Earth recycles inorganic carbon between the atmosphere, surface and oceans over the course of millions of years. Inorganic carbon refers to carbon bound in atmospheric gases, dissolved in seawater or locked in minerals, rather than biological material. This part of the carbon cycle acts like a natural thermostat. When volcanoes release carbon dioxide into the atmosphere, the carbon dioxide molecules trap heat and warm the planet. As temperatures rise, rain and weathering draw carbon out of the air and store it in rocks and oceans.

If the planet cools, this process slows down, allowing carbon dioxide, a warming greenhouse gas, to build up in the atmosphere again. This part of the carbon cycle has helped Earth recover from past ice ages and avoid runaway warming.

Even as the sun has gradually brightened, this cycle has contributed to keeping temperatures on Earth within a range where liquid water and life can persist for long spans of time.

Now, scientists are asking whether similar geological processes might operate on other planets, and if so, how they might detect them. For example, if researchers could observe enough rocky planets in their stars' habitable zones, they could look for a pattern connecting the amount of sunlight a planet receives and how much carbon dioxide is in its atmosphere. Finding such a pattern may hint that the same kind of carbon-cycling process could be operating elsewhere.

The mix of gases in a planet's atmosphere is shaped by whats happening on or below its surface. One study shows that measuring atmospheric carbon dioxide in a number of rocky planets could reveal whether their surfaces are broken into a number of moving plates, like Earth's, or if their crusts are more rigid. On Earth, these shifting plates drive volcanism and rock weathering, which are key to carbon cycling.

Keeping an eye on distant atmospheres

The next step will be toward gaining a population-level perspective of planets in their stars' habitable zones. By analyzing atmospheric data from many rocky planets, researchers can look for trends that reveal the influence of underlying planetary processes, such as the carbon cycle.

Scientists could then compare these patterns with a planet's position in the habitable zone. Doing so would allow them to test whether the zone accurately predicts where habitable conditions are possible, or whether some planets maintain conditions suitable for liquid water beyond the zone’s edges.

This kind of approach is especially important given the diversity of exoplanets. Many exoplanets fall into categories that don't exist in our solar system — such as super Earths and mini Neptunes. Others orbit stars smaller and cooler than the sun.

The datasets needed to explore and understand this diversity are just on the horizon. NASA's upcoming Habitable Worlds Observatory will be the first space telescope designed specifically to search for signs of habitability and life on planets orbiting other stars. It will directly image Earth-sized planets around sun-like stars to study their atmospheres in detail.

Instruments on the observatory will analyze starlight passing through these atmospheres to detect gases like carbon dioxide, methane, water vapor and oxygen. As starlight filters through a planet's atmosphere, different molecules absorb specific wavelengths of light, leaving behind a chemical fingerprint that reveals which gases are present. These compounds offer insight into the processes shaping these worlds.

The Habitable Worlds Observatory is under active scientific and engineering development, with a potential launch targeted for the 2040s. Combined with today's telescopes, which are increasingly capable of observing atmospheres of Earth-sized worlds, scientists may soon be able to determine whether the same planetary processes that regulate Earth’s climate are common throughout the galaxy, or uniquely our own.

BREMEN, Germany — NASA will help Europe get its long-delayed Mars life-hunting ExoMars rover off the ground, even though President Donald Trump's proposed NASA budget cuts the collaboration in a drive to reduce spending on science.

The announcement was made at the European Space Agency's (ESA) Ministerial Council — a high-level meeting of the agency's 23 member states — on Wednesday (Nov. 25).

"I've got yesterday a letter from the NASA administration to confirm the contributions of NASA to Rosalind Franklin," ESA Director General Josef Aschbacher told reporters at the opening of the meeting. "So, this is certainly something that is good news."

The ExoMars Rosalind Franklin rover is a 660-pound (300 kilograms) Mars exploration robot fitted with a 6.6-foot (2 meters) drill to search for signs of life below the Red Planet's radiation-battered surface.

The project, conceived in the early 2000s, has faced multiple setbacks on the way to the launch pad. The mission was originally planned in cooperation with NASA, but the American agency withdrew in 2012 after budget cuts imposed by the Obama administration, forcing ESA to seek support from Russia.

The rover, which is named after a British chemist who played a key role in discovering the structure of DNA, was supposed to lift off atop a Russian Proton rocket from the Baikonur Cosmodrome in Kazakhstan in September 2022 and descend to the Martian surface atop a Russian-made landing platform a year later. But that plan changed in early 2022: ESA severed ties with the Russian space agency Roscosmos in response to Russia's invasion of Ukraine.

NASA then came back into the picture. In late 2022, ESA member states agreed to invest an additional 360 million Euros ($417 million US) to build a new landing platform for the rover. NASA offered to provide a rocket, radioisotope heaters needed to protect the rover's technologies in the frigid Martian weather, and braking retrorockets to safely lower the landing platform to the ground. With new developments needed, ESA established a new launch date for the rover in 2028.

But Donald Trump's election victory last year nearly thwarted those plans, as Rosalind Franklin was among 20 science collaborations between ESA and NASA that Trump's fiscal year 2026 budget proposal eliminated. Since then, speculation has swirled about whether ESA would have to seek additional funding to complete the mission on its own. The NASA contribution to ExoMars is estimated at $375 million, according to the nonprofit space exploration advocacy group Planetary Society.

Speaking at the ESA Ministerial Council, Aschbacher confirmed that NASA will provide all of the three elements it had previously committed to.

"These confirmations have been given to us in writing, so this is a very important step," Aschbacher said.

He added that NASA had already delivered a science instrument to be carried by Rosalind Franklin — the Mars Organic Molecule Analyzer-Mass Spectrometer (MOMA-MS), which will be able to detect the tiniest traces of organic materials in the samples drilled up by the rover. The instrument, ESA's spokesperson said, is currently undergoing integration, testing and verification in Europe.

ExoMars is only one of Europe's flagship science space missions caught in the NASA budget drama. The Laser Interferometer Space Antenna (LISA) gravitational wave observatory comprising three innovative spacecraft is a joint project worth an estimated $3 billion. NASA was to provide about $1 billion worth of technology for the mission, including onboard telescopes and lasers, according to the Planetary Society. The Venus exploration probe EnVision also relies on NASA's help. The American agency was supposed to build an innovative synthetic aperture radar instrument worth an estimated $300 million. That contribution has also been cut by the Trump administration.

Further planned missions, including the X-Ray telescope New Athena and exoplanet watcher Ariel, will be hit if the Trump budget proposal is approved. Both the U.S. House of Representatives and Senate, however, are working to reinstate at least some of that funding. ESA member states will be negotiating ESA's future direction and funding on Nov. 26 and Nov. 27, not knowing how the situation in the U.S. will resolve.

Earlier, a source familiar with the situation inside ESA told Space.com that the agency is working on a rescue plan for LISA and EnVision and believes that Europe could go it alone if need be.

"We are discussing with our member states about their ambition to take responsibility for one or more of the NASA elements should we need to take recovery actions," the source said. "By the middle of next year, we expect to be in a position to decide on the way forward, with clarity on NASA funding and member state ambition and funding."

Aschbacher previously unveiled bold plans to secure a record-breaking budget of over 22 billion Euros ($25 billion) for ESA's next three-year period, up 5 billion from the last budget agreed in 2022. The negotiations, however, come in a tense time period for Europe with countries pressed to increase their defense spending due to worsening tensions with Russia.

Possible giant "karstic" caves that formed when slightly acidic water dissolved bedrock have been identified on Mars and hailed as one of the best locations on the Red Planet to search for preserved biosignatures.

"With the expected technological advances in the coming decades, if missions are specifically designed for these targets, we believe that in situ exploration of Martian karstic caves is an achievable goal," said Chunyu Ding, of the Institute for Advanced Study at Shenzhen University in China, in an interview with Space.com.

The caves, in the Hebrus Valles region between the extinct volcano Elysium Mons and Utopia Planitia in Mars' northern mid-latitudes, are revealed by eight skylights, which are holes in the ceiling of the caves that are visible on the surface as pits ranging from tens to over 100 meters across. The skylights are distinguishable from craters because they don't possess raised walls or splashes of ejecta around them. It is thought that the skylights form when the surface partially collapses into the empty cave below it.

Caves and skylights have been found on Mars before, but as lava tubes formed in volcanic regions. Hebrus Valles, on the other hand, is not a volcanic region; it displays ancient river channels and copious hydrated minerals and sediments deposited by bodies of liquid water on the surface long ago.

These features were identified by scientists led by Ding and his Shenzen colleague Ravi Sharma. Their team used archive data from a variety of Mars missions, including mineralogical maps based on observations by the Thermal Emission Spectrometer on NASA's now-defunct Mars Global Surveyor, hydrogen detections (as a proxy for water) from the Gamma-Ray Spectrometer on the agency's Mars Odyssey, and models of the Martian terrain built around data from the HiRISE camera on NASA's Mars Reconnaissance Orbiter.

They determined that the skylights and their surroundings are consistent with what's termed "karstic" caves. Karstic refers to the dissolution of carbonate- and sulfate-bearing bedrock. While we find karstic caves in many locations on Earth, this is the first time that they have been identified on Mars.

The observations show that the Hebrus Valles region is rich in carbonate rock such as limestone and sulfate rock such as gypsum. Over 3.5 billion years ago, when Mars was warmer and wetter, these carbonate and sulfate sediments were laid down by large pools of liquid water, such as lakes and seas. When Mars grew cold, the surface water went away, much of it forming sub-surface ice and frozen brines.

Indeed, the Gamma-Ray Spectrometer data from Mars Odyssey points to water ice possibly still existing there in some quantity. At some point, local heating events, perhaps from distant volcanoes, impacts or long-term orbital variations, would have melted the subsurface ice and brines, and the liquid water would have run through cracks and fractures in the ground, dissolving the rock and turning those cracks into large caves.

Not all regions of Mars meet the requirements to form karstic caves, since for one thing carbonate and sulfate rocks are not omnipresent. Nor do all locations, particularly lower-latitude areas, host subsurface ice and frozen brines or have been geologically stable for long enough to allow the caves to form and their rocky ceiling to collapse and form the skylights.

"Our results suggest that Hebrus Valles is unlikely to be a completely isolated case, but these caves also will not be everywhere on Mars," said Ding. "They are likely concentrated in a limited set of regions that satisfy the necessary depositional and hydrological conditions. It is quite reasonable to expect more karstic caves to be discovered in other, similar environments in the future."

Indeed, more than just the eight caves may be present in Hebrus Valles; there could be others that have not yet experienced a ceiling collapse and revealed themselves. Of those known so far, the skylights appear to be several tens to over 100 meters across, and underground the cavities could be several times larger still, and tens of meters deep.

Karstic caves are the perfect location to preserve ancient biosignatures. The watery and stable microclimate within the caves long ago could have hosted microbial colonies, and today the caves are protected from the extreme conditions on Mars' surface, such as wildly different diurnal temperatures, dust storms and solar ultraviolet and cosmic-ray radiation. Hence future life-seeking missions may seek to explore them.

However, the surrounding rock will limit the transmission of radio signals from inside the caves to orbiting spacecraft, making exploration of the caves more difficult, but not impossible, said Ding.

"From an engineering standpoint, directly entering these caves is a major challenge," he said. "However, our geomorphological analysis suggests that not all candidate caves are simple vertical shafts. In our paper, we use the term 'accessible potential karstic caves.'"

Most of the skylights are characterized by steep walls descending down into the darkness of the caves, but among the eight Hebrus Valles caves there is evidence for slopes made by rocky debris in multiple, step-like formations that might allow a staged descent.

This could be accomplished by multiple robotic explorers forming a communications chain down into the caves, ranging from wheeled rovers that carefully navigate down each step, to climbing robots lowered by winches or aerial rotorcraft that can fly in and out of the skylights.

The cave's rocky shielding might not only lend itself to preserving biosignatures, but could also offer protection to future Mars astronauts, shielding them and their outposts from the hazards of radiation and dust storms on the surface. If so, it could be that humanity's future on Mars is to be found underground.

The conclusions of Ding's team were published on Oct. 30 in The Astrophysical Journal Letters.