Scientists once suspected that a brutal, years-long winter starved the dinosaurs following an asteroid impact 66 million years ago. New evidence suggests a more violent end: widespread firestorms that may have burned even thick-skinned dinosaurs to a crisp within hours.

The roughly six-mile-wide (10-kilometer-wide) asteroid struck Mexico's Yucatán Peninsula, excavating the Chicxulub crater and vaporizing enormous quantities of rock. Some of that material condensed into tiny droplets called spherules, which spread around the planet before falling back through Earth's atmosphere at several miles per second.

As the spherules slowed, their kinetic energy became heat, producing an intense pulse of thermal radiation. Earlier models suggested the effect would have resembled a worldwide broiler that was potentially deadly to exposed, thin-skinned animals, but not powerful enough to ignite vegetation across the globe.

A new study argues that those calculations overlooked a crucial ingredient: a thick layer of fine silicate dust formed from rock vapor that did not initially condense into spherules. Evidence for that dust emerged in 2023 from the Tanis fossil site in North Dakota, where researchers identified a layer of extremely fine, impact-derived material deposited above the spherules. A similar dust layer has since been documented at the K–Pg boundary (which divides the "age of reptiles" and the "age of mammals") in Raton Basin across the Colorado–New Mexico border.

"It reinvigorated my interest in what happened to the leftover vapor — that's where this work started," lead author Brandon Johnson, a planetary scientist at Purdue University, said in a statement.

The dust would have acted like an insulating blanket, preventing thermal radiation from escaping into space and redirecting more heat toward Earth’s surface. The researchers estimated that the surface heat pulse could have been about 3.5 times more intense than what was suggested by models considering the falling spherules alone. "We're in the realm where we might be essentially killing off everything within that first hour or two," Johnson said.

The radiation may not have directly ignited thick pieces of wood, but it exceeded ignition thresholds for grass, lichen, and pine needles, which could have fueled larger fires. The study also found that exposed terrestrial animals may have received about 17 times the thermal dose considered lethal to humans.

Animals sheltering underground or in water would have had a better chance of surviving the initial heat pulse. Afterward, the same dust may have blocked sunlight for years, triggering the prolonged "impact winter" more typically blamed for the dinosaurs' extinction.

There is, however, a missing element: the wildfire evidence that supports this dust-caused inferno theory has only been found in North America. "It could be that we will eventually find the record of completely global wildfires," said Alfio Alessandro Chiarenza, a paleontologist at University College London who was not involved in the study. "We just don't have it so far."

The study was published on July 28 in the journal JGR Biogeosciences.

Scientists have found the first triple-lobed asteroid in the asteroid belt between Mars and Jupiter — and it has a small moon to boot.

The asteroid in question is 44 Nysa, which was discovered all the way back in 1857. Of course, back then it was just a pinprick of light in the sky, and subsequent observations — including some from the Hubble Space Telescope — had failed to tell us much about Nysa. Those previous observations suggested Nysa might be bi-lobed, like many asteroids and comets such as asteroid 52246 Donaldjohanson, which NASA's Lucy mission flew past in 2025.

However, new joint observations by the Large Binocular Telescope (LBT) on Mount Graham in Arizona and the Very Large Telescope (VT) on Paranal mountain in Chile have revealed that this asteroid actually seems to have three lobes, the first such object ever seen.

"The images reveal a remarkably unusual object," said lead researcher Kate Minker of Arizona's Lowell Observatory in a statement. "The most likely explanation is that Nysa is either a contact trinary, consisting of three connected components, or an extremely irregular coherent body unlike anything we've previously observed."

Obtaining the detailed images of Nysa was not easy. Key to the success were two high contrast imaging devices, the Italian-built SHARK-VIS on the LBT and SPHERE and its ZIMPOL polarimeter on the VLT, used in conjunction with adaptive optics that counteract the blurring effect of the atmosphere.

"These observations had to be combined with specially developed image-processing techniques to further sharpen the images and remove the bright halo surrounding the asteroid, potentially hiding faint companions," said Anthony Berdeu of the European Southern Observatory.

The images showed an irregular-shaped body 47 miles (75 kilometers) at its widest point, with two notable valleys or "colli" that wrap around the asteroid's circumference and which Minker's team interprets as being the necks of the different lobes. Furthermore, the images revealed a 0.6-mile-wide (1-km-wide) moon orbiting Nysa at a distance of at least 106 miles (170 km). The moon has been designated S/2026 (44) 1 for now. And, because it was seen independently during two different observing campaigns, it was possible to observe its motion around Nysa.

"We borrowed a specialized technique from another field of astronomy, known as high-contrast imaging, to detect the small moon whose faint light was overwhelmed by the intense brightness of the primary asteroid," said Gianluca Li Causi of the SHARK-VIS team at the Italian National Institute for Astrophysics (INAF).

Nysa is named after the mythical land where the ancient Greek god Dionysus was raised by nymphs. Al Conrad of the Large Binocular Telescope Observatory finds the name fitting because Dionysus was the Greek god of theater, which for the ancient Greeks often involved wearing masks and hiding one's true identity.

"We're finally unmasking the asteroid's true nature, long after it was discovered," said Conrad.

How such a bizarre object formed remains uncertain, but Minker's team does have a couple of ideas.

The team's preferred explanation is that Nysa is a contact trinary — three asteroid bodies being held together loosely by gravity. The best alternative, the researchers say, is that Nysa once upon a time had a close encounter with a much larger asteroid that slammed into it, thereby deforming it. In these situations, modeling suggests that gravitational tidal forces could have deformed Nysa's mantle, creating Nysa's odd shape and even ripping it apart into a bunch of fragments in a string-of-peals configuration. If this is the case, then where did the other fragments go? Such events usually produce a family of asteroids all sharing the same composition, but Nysa seems to be alone (barring its moon, of course).

There could be a way to distinguish between the two possible origins. By tracking the moon's orbital velocity and period, astronomers will be able to pin down the exact mass and density of Nysa and then see which model matches it best.

Nysa has been a subject of study because it can also tell us about the birth of our own planet Earth. Nysa is more reflective than many other asteroids thanks to its surface composition that is abundant in a silicate mineral called enstatite, which lacks iron. Asteroids like this are generally called E-types, and Nysa is the largest and brightest of all of them. E-type asteroids are thought to have formed close to the sun and therefore have been identified as potential building blocks of the inner planets. If Nysa is a relic of that time, it could tell us a great deal about conditions in the inner solar system 4.5 billion years ago.

The findings can be read on the arXiv archive, and have been submitted to the journal Astronomy & Astrophysics.

The diets of penguins on Antarctica's Danger Islands can be seen from space. At least indirectly.

Using satellite images captured by the Landsat 8 spacecraft operated by NASA and the United States Geological Survey, scientists can track changes in Adélie penguins' diets based on the color of their guano, or droppings.

What is it?

The image above shows pinkish-orange guano staining large sections of some of the Danger Islands, Heroína Island and Beagle Island. The penguins that live there eat a diet rich in krill, small marine crustaceans that are bright pink in color due to a specific type of algae upon which they feed.

The bright pink color of the penguins' droppings stands out in satellite imagery, allowing researchers to monitor the birds' populations from space. But scientists wanted a closer look, and collected drone imagery as well, as seen in the image below.

Why is it incredible?

It's pretty amazing that the diet of a specific population of birds can be monitored from 438 miles (705 kilometers) above Earth's surface. The imagery collected by Landsat-8 helped scientists locate where the penguin colonies might be, allowing them to find them in-person and collect guano samples. Those samples contained evidence of what the penguins were eating over time.

Researchers are using those satellite images and samples to track how the penguins' diet might be affected by changes in sea ice conditions, according to a NASA statement.

"Sea ice is such a hugely important factor in the Antarctic marine environment," said Clemson University biologist Casey Youngflesh who led a study comparing the penguins' diet and sea ice conditions. "The structure of the region's food web is changing in response."

On Aug. 5, Earth's moon is due for a human-made, high-speed impact from an identified flying object: a spent SpaceX Falcon 9 upper stage. The event will lead to a literal "dust up" on the lunar landscape.

That Falcon 9 upper stage is a leftover from the launch that sent Firefly's Blue Ghost-1 lander to the moon on Jan. 15, 2025. Onboard the same flight was the Hakuto-R Mission 2, called Resilience, a robotic lunar lander developed by the Japanese company ispace.

And according to a new study by an international team published on the open-source arXiv server, the resulting impact plume may briefly be bright enough to see against the dark sky near the moon's edge. That means it might be visible to moongazers with sufficiently sensitive telescopes.

This head-on collision of the errant stage is expected to occur near the Einstein and Bell craters near the western lunar limb. It may well be visible to ground and space-based assets. Indeed, putting aside all the unknowns and modeling uncertainties, some specialists suggest if you've got the time and observational prowess, it might be worth a look.

Visible ejecta spike

Using special physics simulations to model the impact, William Jo, a graduate research assistant at the University of Texas, Austin and colleagues predict the debris plume from the impact will have the central ejecta spike reaching roughly 47 miles to over 60 miles (75 kilometers to 100 kilometers) altitude.

"Our calculations suggest the plume should be several orders of magnitude brighter than the dark-sky background for the first few minutes after impact," Jo told Space.com. "So the plume should be visible, though I'd stress this is a single nominal case. The real one will look different, and the numbers are on the optimistic side. But the point worth making is that the flash isn't really the story here."

Jo emphasized that there's great slam-dunk science to be had. "Watching this one gives us a rare chance to open up ejecta-plume science and calibrate those models against a real event, which matters for every future thing we deliver to the moon," Jo said.

Implications for future moon missions

According to new research led by Benjamin Fernando of the Los Alamos National Laboratory in New Mexico, the impact flash and resultant ejecta plume are "potentially observable" from ground- and space-based observational facilities.

"This event provides an opportunity to attempt the recording of an artificial impact in real-time; although many of the properties of the event (such as visual magnitude) are imprecisely predicted at present," Fernando and colleagues report.

Moreover, this rocket stage meets moon occasion yields an opportunity to test a pipeline for localizing impacts on the lunar surface for future seismic experiments, investigating the dust and plume dynamics from impact events on the moon, and considering hazards from artificial space debris impacts that future astronauts on the lunar surface might have to avoid, Fernando and team members point out.

"The maximum ballistic range of resolved particles is found to be slightly under 1,000 km, which is far enough to be significant from the perspective of presenting a hazard to future astronauts or infrastructure across much of the lunar surface," Fernando et al wrote in the study.

Before and after

Brent Garry is a project scientist for NASA's Lunar Reconnaissance Orbiter (LRO) at Goddard Space Flight Center in Greenbelt, Maryland. LRO will be passing over the projected rocket stage crash site about seven days prior to the impact and about seven days after the impact, Garry explains.

"After the impact we might have a little bit more knowledge of where it is. We can do some additional targeting about a week after the impact and get some targeting over where the site is," said Garry, as noted in earlier Space.com reporting.

Meanwhile, Jo at the University of Texas, Austin underscores the fact that a spent rocket stage is a hollow, spacecraft-like body, and there are very few impact models for human-made objects like it. They seem to produce very different plumes than natural impactors, like asteroids or comets do. But Jo stresses that the real scientific contributions will come by studying the moments after the impact.

"My concern is that most observers will stop at the sub-second flash and never track down the ejecta, which is the part that should actually be visible, and where the science is."

China's Chang'e-8 moon lander mission scheduled for 2029 could send Africa's first space exploration mission to the lunar south pole.

Under the Africa2Moon venture, the Bounced African Low Lunar Sphere, or BALLS for short, is a technology demonstrator in which a trio of spherical probes on the lunar surface will form a radio astronomy array at the moon's south pole region. Each of the metal spheres contains low-frequency radio telescope antennas that will search for signals from some of the oldest and most distant parts of the universe.

Astronomers say the lunar far side is the most radio-quiet site in Earth's vicinity, a location perfect for "listening" to the universe without interference. The BALLS array will work together to observe low frequency radio signals from space that are not observable from the surface of the Earth, according to Carla Mitchell, mission director of the Africa2Moon initiative and Africa Program manager at the South African Radio Astronomy Observatory (SARAO). The moon is an ideal place to perform such studies, they said, as the low frequency signals to be measured are unobservable from Earth due to interference created by our planet's atmosphere.

Pathfinder

The Africa2Moon project was selected by the Chinese National Space Administration in April 2025 as one of nearly a dozen of Chang'e-8's international payloads.

BALLS will enable observations below 20 megahertz (MHz) that are inaccessible from Earth due to ionospheric distortion and radio interference. Low-frequency radio waves (below about 50 MHz) come from some of the oldest and most distant parts of the universe.

The BALLS array will serve as pathfinder hardware for future lunar technologies and radio astronomy experiments. They will also act as a technology demonstrator for the full Africa2Moon mission, which plans for an array of 55 antennas to be deployed on the far side of the moon.

From paperwork to hardware

"As a little girl I thought space was not possible for people in Africa. I never thought I would be here today, presenting our lunar mission at NASA," said Mitchell.

Mitchell detailed years of team work on the BALLS initiative, rolling forward from paperwork to hardware, speaking July 22 at the NASA Exploration Science Forum 2026, held at NASA's Ames Research Center and staged by the NASA Solar System Exploration Research Virtual Institute (SSERVI).

SARAO is the national radio astronomy facility of South Africa, operating and managing such facilities as MeerKAT and the South African Square Kilometer Array (SKA) project. SARAO is involved in a range of cosmic inquiries, from pulsar research to studying fast radio bursts, dark matter and dark energy.

Spaced out

Once deployed on the moon, the BALLS trio would be spaced out on the lunar surface. Signals captured from the BALLS array are to be communicated to the Chinese lander and then relayed back to Earth for further processing.

Each of the BALLS consists of a spherical gyroscope-like frame made of interlocking rings, encasing two large triangular solar panel arrays with a grid-like surface texture. The panels are oriented in opposite directions — one pointing upward and one downward — giving the structure a tetrahedron-like inner form.

The mission is led by the Foundation for Space Development Africa in collaboration with SARAO, the South African National Space Agency, the National Institute for Theoretical and Computational Sciences, as well as institutions in Kenya, Ghana, Botswana and across the continent.

Teams at Petrawell in Cape Town, Aerospace Systems Research Institute at the University of KwaZulu-Natal and Electronic Systems Laboratory at Stellenbosch University were involved in manufacturing the components of the structural and functional BALLS models. They were assembled in April 2026, to be delivered to China's Chang'e-8 team for testing.

"The power of collaboration, education and hope cannot be underestimated for Africa's future in space science and technology," she said.

Looking to a second mission

As for the full Africa2Moon mission consisting of 55 antennas emplaced on the far side of the moon, Mitchell said they would require a launch as with the first mission.

"So yes, it would probably be contingent on China partnering again with us," Mitchell told Space.com.

The design of the second mission instruments would be a little different too.

"We would want to have them a little larger in diameter and so they would have to go in a flat version that will deploy into a ball versus the current version that travels as a ball, due to space constraints," Mitchell said.

"The deployment onto the lunar surface would also be different, as in self-deploying from the lander as opposed to a robot deployment. This would enable a faster and more random and further dispersed deployment pattern, which enhances the science," she said.

Shoe-string budget

"I am amazed that it is being done on a shoe-string budget by volunteers. This demonstrates the inspiration of space and if this is successful, it will ignite the reality of space on the African continent," said Clive Neal, a lunar science exploration specialist and professor in civil and environmental engineering and Earth sciences at the University of Notre Dame.

Attending Mitchell's talk at the recent forum at Ames Research Center, Neal said the broader lunar exploration community is willing to help if needed.

"Her talk was inspirational," Neal said, "especially as the broader planetary science community over here [in the U.S.] is moaning about the lack of funding!"

Radio telescopes are designed to listen for signals from the stars and from distant galaxies, but scientists are also pointing out that these instruments can also track objects somewhat closer to home: junk in Earth's orbit.

Engineers have used the famed radio telescope at Jodrell Bank in the U.K. as part of an international plan to watch high-altitude space debris. Normally, old satellites and bits of spacecraft stuck up in geostationary orbit are too high up for our normal ways of watching space debris. However, said international project, called Long Baseline Multistatic Radar (LBMR), successfully used a radio telescope to get around this problem.

"That's the first time that's ever been done," Simon Garrington, associate director of Jodrell Bank, said in a video about the project.

A pressing problem

It's hardly a secret that junk is rapidly piling up in Earth's orbit — dead satellites, rocket remnants, rubble from satellite collisions or anti-satellite missile tests, and more. And as we keep filling Earth's orbit with thousands more satellites each year, we're also increasing the risk that one is struck by a debris fragment. We need to track this debris.

Most satellites exist in low Earth orbit (LEO) below altitudes of 1,250 miles (2000 kilometers), and indeed space debris is more concentrated at LEO. Still, there’s good reason to be just as concerned about debris in the much higher geostationary orbit (GEO), which falls 22,500 miles (36,000 kilometers) in altitude. Crucial communications and weather satellites lie in GEO, for instance, and space debris doesn't need to come in great quantities to pose a threat — just one unfortunate strike can cripple a satellite.

This leaves debris-hawks with a conundrum. They typically track space junk in LEO with radar, but most ground-based radar systems aren't sensitive enough to watch GEO's heights. Instead, they rely on optical telescopes to see objects in GEO. These telescopes are good for tracking larger objects (larger than about 4 inches, or 10 centimeters, across), but they can't resolve smaller objects as well as radar can. Yet these smaller objects can be just as deadly and destructive as their larger counterparts. If we want to see them with radar, we'll need especially sensitive receivers.

Fortunately, that equipment already exists, too — that's where radio telescopes can help.

Engineers have tried debris-watching with radio telescopes as early as the 1990s, but LBMR, backed by NATO and the U.K. Space Agency, wanted to go further and watch debris in real time.

LBMR's engineers drew up a scheme to make this work. They would broadcast radio waves with a radar installation at the Massachusetts Institute of Technology's Lincoln Laboratory in the U.S. These radio waves would glance off debris and fall back into the dishes of U.K. radio telescopes such as the Lovell Telescope at Jodrell Bank. Back on the ground, the radio telescope's signal would be processed and analyzed in real time.

Aligning a radar transmitter with a radio telescope on the far side of an ocean, then processing its signals, is far easier said than done.

"This idea started about seven years ago. It sounded at that time like a crazy idea, because we had no synchronization. We had assets on one end of the ocean and other assets on the other end of the ocean," said Marco Martorella, an electronic engineer at the University of Birmingham and another member of LBMR, in a video. "But we were crazy enough to continue."

This required years of work, but the researchers have now successfully demonstrated that they can receive a signal with a single antenna. This has allowed them to track the distance to a piece of debris, and how quickly that distance is changing, in real time.

Next, the LBMR researchers hope to demonstrate that they can receive radar reflections of the same object with multiple radio telescopes at once. This, the researchers say, would allow debris-hawks to use the radio telescope technique to truly track debris in three dimensions.

NEW YORK — Madison Square Park in midtown Manhattan is home to some 44 tree species. And on a Thursday afternoon blanketed in wildfire smoke, a small crowd gathered to see one in particular. The slender American sweet gum looked unassuming, especially compared to the enormous English elm neighboring it. But this tree had a secret: it had traveled 1.3 million miles before landing in New York.

The sapling was germinated from one of 1,000 seeds NASA sent aboard the uncrewed Artemis I mission, which saw a space capsule orbit the moon in 2022. Just a few years later, the same kind of capsule would take the famous Artemis II crewmembers on the same journey. Hundreds of these "moon trees" have been planted across the U.S. in the last two years as the space agency drums up excitement for future Artemis missions, which aim to return humans — and not just seeds — to the lunar surface by 2028.

Steph Lucas, director of horticulture for the Madison Square Park Conservancy, applied with NASA for a moon tree seedling in 2023. The request was finally granted in 2025. "We were so thrilled," Lucas told Space.com. The tree grew quietly for a year before the conservancy unveiled its presence with a "birthday party" extravaganza on Thursday (July 16).

Madison Square Park's moon tree is part of a legacy spanning back to NASA's original lunar program. In 1971, astronaut Stuart "Smoky" Roosa brought about 500 seeds aboard the Apollo 14 moon mission. These seeds later grew into saplings that NASA distributed to parks, arboretums and historic sites across the globe. A seed from one of these first-generation moon trees even attended the new tree's birthday party.

The event also featured a celestial-themed garden, poetry reading, a gallery of children's artwork, launch-able foam rockets and, of course, birthday cake — enough for about 100 people.

However, the party had fewer guests than expected. A thick plume of smoke from wildfires raging in Canada blew southward and tinted the sky above New York orange. The air quality plummeted, and many people chose to remain indoors for their health. Some of those who did turn up wore KN95 masks.

In a strange way, the atmosphere was fitting. The specter of climate change hung heavy over the city, and it was very much on Lucas' mind as she was vying for the conservancy's moon tree selection. NASA offered five different species of moon tree: Douglas fir, Loblolly pine, Sequoia, London plane and American sweet gum. Lucas requested an American sweet gum over a more cold-hardy London plane tree, even though its current range falls slightly south of New York City. Sweet gums are well-adapted to wet, temperate conditions, and as the climate warms in the coming decades they will likely feel right at home in Manhattan. "We think that this will be a better selection as the future goes on," said Lucas.

Stuart Roosa himself was a former smokejumper for the US Forest Service, a job that involves dropping from a helicopter into the heart of an active wildfire to fight it. He agreed to bring along those first moon seeds as a love letter to future generations on Earth. That's the spirit the Madison Square Park Conservancy hopes to channel.

"Space inspires us, right? And plants can be inspiring too," Lucas said. After a year of growth, the park's moon tree is now firmly rooted and standing tall without supports. Gazing at it through the wildfire haze, Lucas mentioned that the young tree seems by all accounts to be thriving. Its progress, she said, brings her hope. "We can always work towards a better future."

Scientists have measured temperatures beneath the surface of Jupiter's volcanic moon Io, offering the first-ever glimpse of the hidden heat driving the most volcanically active world in the solar system.

During close flybys of Io in late 2023 and early 2024, NASA's Juno spacecraft turned its Microwave Radiometer (MWR) instrument toward the moon, probing roughly six to 20 feet (two to six meters) beneath its surface. Originally designed to peer through Jupiter's thick clouds, the instrument instead revealed a powerful new way to study how heat moves through planetary crusts, according to a statement from the space agency.

"The surprising discovery that we could see below a rocky moon's surface has important implications for studying Earth's volcanoes," Scott Bolton, coauthor of the study and Juno's principal investigator, said in the statement. "Juno has taught us that if we look with an MWR-type instrument near a volcano on Earth, we might see a similar signature in the subsurface temperature gradient, providing new information on how terrestrial volcanoes work."

Until now, researchers had relied almost entirely on infrared observations, which detect only the temperature of Io's surface. By probing several feet underground, Juno has revealed how heat moves through the moon's crust for the first time.

The measurements showed temperatures rising by more than 40 degrees Fahrenheit (22 degrees Celsius) just a few feet below the surface — far more than sunlight alone could explain. Juno's subsurface heat map also revealed localized regions of elevated heat, with temperatures measuring between 18 and 36 degrees F (10 to 20 degrees C) warmer than the surrounding terrain, according to the statement.

Juno's observations uncovered another surprise, too. Despite being known for its towering mountains and active volcanoes, much of Io's surface appears remarkably smooth and composed of unusually low-density material. Researchers think the moon is blanketed by porous layers of volcanic ash, sulfur frost and other eruptive debris that continually resurface Io, burying older terrain beneath fresh deposits.

Scientists think the heat detected beneath Io's surface could be rising steadily from the moon's molten interior through a conductive crust or coming from pockets of cooling lava flows trapped just below the surface. Either way, the data provide the clearest picture yet of how Io transports heat from its interior.

Unlike Earth, where volcanism is driven largely by heat from radioactive decay, Io is continuously stretched and squeezed by Jupiter's immense gravity as it orbits the giant planet. This constant tidal flexing generates enormous amounts of internal heat, fueling hundreds of active volcanoes and making Io the most volcanically active object in the solar system. By improving scientists' understanding of how heat and magma move beneath a planet's surface before eruptions, the same microwave techniques used by Juno could one day help researchers better monitor Earth's volcanoes and improve eruption forecasting.

"Io provides a unique window into learning how tidal heating works throughout the cosmos, a fundamental process that provides energy and heat to worlds that are far from their parent star," Bolton said in the statement. "This process can not only create the most volcanic body in the solar system, in the case of Io, but also fuels the subsurface oceans on the moons of giant planets, such as Europa and Ganymede. Up until this point we could only observe the heat escaping at the surface or through eruptions. Now we can characterize how the heat is moving from the interior toward the surface."

Because Io is an extreme example of volcanic activity, it serves as a natural laboratory for studying how heat moves through planetary crusts. Those insights could help scientists better understand ancient volcanism on Mars, Venus, and Earth's moon, whose landscapes were shaped by massive eruptions billions of years ago.

The technique could also aid the search for life elsewhere. While Io itself is far too hostile to support life, microwave instruments can also probe beneath icy surfaces. Juno has already used the same instrument to study Jupiter's moons Europa and Ganymede, where scientists believe vast oceans lie hidden beneath thick shells of ice. Understanding how heat moves through those crusts is key to determining whether they could harbor environments suitable for life as we know it.

Their findings were published July 22 in the Journal of Geophysical Research: Planets.

Hey, Space Fans! Every weekend here at Space.com, you may have noticed we highlight the latest episode of the podcast This Week In Space, a TWiT show co-hosted by yours truly and my friend and colleague Rod Pyle, a space historian and editor of the National Space Society magazine Ad Astra.

This Week In Space episodes usually drop each Saturday, but this week we're doing something a bit different. To mark the 50th anniversary of NASA's Viking landings (Viking 1 touched down on Mars on July 20, 1976), Rod and I will host a special live taping of the podcast to discuss all things Martian starting at 1:30 p.m. EDT (1730 GMT). It should last up to 90 minutes.

Joining us on the podcast will be:

• Dr. Pascal Lee, a planetary scientist, geologist and artist with the SETI Institute, Mars Institute and NASA Ames Research Center.
• Dr. Penny Boston, an astrobiologist and speleologist (the study of caves) with the New Mexico Institute of Mining and Technology.

During our discussion, we'll touch on the personal and scientific impacts of NASA's Viking Mars landings and look at where Mars exploration may go in the modern age. We might even discuss the best places for the hunt for signs of life: the surface or inside Martian caves?

So if you're a Mars fan or a casual space aficionado, join us today at 1:30 p.m. EDT to get a detailed look at NASA's Viking Mars landings and their lasting impact on Martian exploration.

For several years now, astronomers who study the sun have faced a little mystery — our star seemed to hold too little silver. Whenever scientists examined the sun's outer layers, they've seen significantly less silver than they've expected to find.

Where, then, did the missing silver go?

As it turns out, this mystery may finally be solved. Newly published research suggests that the sun's missing silver may have been hiding in plain sight all along.

At first, the real mystery might seem to be why you'd seek silver in the sun at all. After all, 98.5% of the sun's mass is made from lightweight hydrogen and helium. Silver is just a tiny fraction of the remaining 1.5%, which also includes traces of other heavy elements like iron and copper.

These trace elements can illuminate the history of the cosmos. Silver is thought to form when dying stars violently explode in supernovas. When astronomers find silver in the sun and other stars, they can retrace the silver's origins and how stars have evolved over the eons.

"By studying the light of stars of different types and ages, we hope to understand where silver is formed in the universe, and how it has been distributed throughout the Milky Way over time," says Sema Caliskan, the lead author of the research and now a postdoc at the University of Liège in Belgium, in a statement.

Silver is particularly interesting because it's also found in utterly ancient meteorites called CI chondrites. These meteorites formed from the same primordial matter that created the sun, 4.6 billion years ago. As a result, when scientists break into CI chondrites that have fallen to Earth, they expect to find silver levels that match those they see in the sun.

Astronomers can measure the latter from afar by looking at sunlight's spectral lines. As light streams out from the sun's heart, it crashes into the atoms of our star's outer layers, which absorb the light at certain wavelengths. Look at a spectrum of sunlight, and you'll see dark lines where light has been absorbed. Atoms of different elements absorb different wavelengths, so each element leaves a distinct fingerprint.

Scientists can pore over these spectral fingerprints to reconstruct what elements created them and in what quantities. Therein lies the mystery: The sun seemed to contain much less silver than CI chondrites would indicate. This missing silver is a source for confusion in the sun's history.

Caliskan and her colleagues wondered if astronomers were missing something. They could not visit the sun in person, but they could still find where the silver might be hidden by simulating the sun's atoms on a computer. If they could create a high-silver model that still spawned the low-silver spectral lines, that model could be a good guess for the silver's whereabouts.

Other scientists had tried this before to limited success, but their simulations had been relatively simple. As light strikes an atom, the light has all sorts of intricate effects on the atom's innards. These effects can alter how the atom absorbs the light and, therefore, change how astronomers see that light.

Past models hadn't accounted for many of these tricky "non-equilibrium effects", because simulating them is far easier said than done. They're messy and complex and they vary a great deal from atom to atom.

In fact, no known scientists had ever tried to simulate a silver atom with non-equilibrium effects before Caliskan and her fellow investigators took on the challenge. They tried with their best guesses and the power of the Tetralith supercomputer in Linköping, Sweden.

Indeed, these non-equilibrium effects seem to explain the silver mystery. Based on their model, Caliskan and colleagues calculated that the sun holds 55% more silver than astronomers have measured.

This isn't a perfect match for the CI chondrites, but it's close enough that investigators can rule out any extraordinary cause. Instead, the missing silver may have been right there, in the sun all along, simply occluded from astronomers' view by tricks of physics. Next, Caliskan and colleagues plan to use this method to simulate other types of stars.

They published their work in the journal Astronomy & Astrophysics in July 2026.

In satellite data captured over Antarctica, what appears to be a beautiful, colorful hummingbird emerges from the crest of a mountaintop.

What is it?

While there are no hummingbirds flying around Antarctica, we can see what looks like a small, purple bird in a new satellite image of an Antarctic mountain. The dark belly of this "bird" at the center of this image is actually the top of the mountain Nunatak Zaterjavshijsja in East Antarctica.

What looks like a bird's tail is a stream of ice flowing northeast all the way out to the ocean, and what appear to be feathers splaying outward from the mountaintop are actually crevasses down the mountain. These crevasses are formed by a glacier fracturing the mountain's surface as it flows in the icy current toward the ocean.

This view was captured by radar instruments onboard the satellite NISAR (NASA-ISRO Synthetic Aperture Radar) that launched as a collaboration between NASA and ISRO (Indian Space Research Organisation). The director of NASA's Earth Science Division called NISAR "the most sophisticated radar we've ever built" in a pre-launch briefing last year.

Why is it incredible?

At first glance, this image is puzzling. What could it possibly be? Its bold colors and sharp lines evoke almost alien qualities. But the strange beauty of the shapes and colors in this satellite image reveal important information about glacier movements on the mountain.

"First, it's a beautiful image, with rich details of features that provide insights to how the glacier is moving. Then, because radar can often see through snow and deep into the ice, NISAR can observe fundamentally different properties of Antarctic ice than can be seen in optical imagery," Seongsu Jeong, the signal analysis engineer who produced the image at NASA's Jet Propulsion Laboratory, said in a statement. "With NISAR we're seeing what's hidden beneath the surface."

And now anyone can explore NISAR's data. Earlier this week, on July 20, NISAR started making the data from its radar instruments public. Moving forward, mission teams will be rolling out this data so researchers everywhere can use it to study and protect our ever-changing planet.

A near-Earth object that astronomers believed was an asteroid for nearly three decades has been unmasked as a faint, active comet, revealing a case of cosmic mistaken identity that could help improve planetary defense.

The object, known since its discovery in 1998 as 1998 SH2, appeared to be an ordinary asteroid. It follows a 4.5-year orbit around the sun and showed no obvious signs of cometary activity, such as the glowing coma or tail produced when sunlight vaporizes surface ice.

However, during a close pass about 2 million miles (3 million kilometers) from Earth in August 2025, researchers using NASA's Deep Space Network planetary radar system noticed something unexpected: The object wasn't where orbital predictions said it should be, according to a statement from the space agency. That discrepancy prompted scientists to take a closer look, and what they found surprised them.

Using decades of precision optical astrometry — measurements of the object's position against background stars — researchers found that gravity alone couldn't explain its irregular motion. Instead, they detected tiny nongravitational forces consistent with jets of gas escaping from the object's surface as hidden ice warmed in sunlight.

"After we measured the nongravitational perturbations affecting the motion of 1998 SH2 and recognized they weren't compatible with the object being an asteroid, we suspected the object could be an active comet," Davide Farnocchia, lead author of the study and navigation engineer with NASA's Center for Near-Earth Object Studies at the Jet Propulsion Laboratory, said in the statement.

To test the idea, the team observed the object with the European Southern Observatory's Very Large Telescope in Chile and the Canada-France-Hawaii Telescope atop Mauna Kea. The observations revealed a faint but unmistakable comet tail, confirming the object's true identity.

The discovery earned 1998 SH2 a second designation: P/1998 SH2, officially recognizing it as a comet. Beyond solving the mystery, the finding has important implications for planetary defense.

Unlike rocky asteroids, comets can subtly change course as gas escaping from their surfaces acts like tiny thrusters. Identifying those nongravitational forces allows scientists to more accurately predict an object's future orbit and assess any potential impact risk.

"This work shows the importance of continuously tracking near-Earth objects," Farnocchia said in the statement. "Because of outgassing, the motion of comets is more significantly perturbed than that of asteroids.

"Detecting these perturbations can be an important diagnostic tool for planetary defense that will help understand which objects may be comets rather than asteroids, how their orbits evolve, and how that influences their Earth impact risks."

The study also suggests that 1998 SH2 may not be unique. The researchers noted that analyzing the motions of near-Earth objects with increasingly precise astrometry could reveal more hidden comets that have long been classified as asteroids because they lack obvious tails or glowing comas.

As astronomers continue to monitor the growing population of near-Earth objects, subtle orbital changes may prove just as revealing as spectacular comet tails, uncovering more examples of cosmic mistaken identity while helping scientists better understand which objects pose potential threats to Earth.

Their findings were published July 10 in the journal Nature Astronomy.

You're looking at history. What might seem like a simple black-and-white picture of some rocks is actually the first photograph ever taken on the surface of Mars.

What is it?

Bright and early on the morning of July 20, 1976, NASA's Viking 1 lander touched down on the surface of Mars. This moment 50 years ago marked the first fully successful touchdown on the Red Planet, and, pretty much as soon as it landed, Viking 1 captured the first image of the Martian surface.

The Soviet Union had already made multiple Mars landing attempts, all of them failures to some degree. The nation's Mars 3 lander did manage to survive its landing initially in December 1971, but it lost contact less than two minutes later.

Viking 1 did more than just survive. While its mission tasked the lander with studying the planet for 90 days after landing, it lasted over six years on the planet and made some incredible observations. The Viking 1 lander worked in tandem with an orbiter by the same name, and was soon joined at Mars by Viking 2, another lander/orbiter pair.

Why is it incredible?

It has now been 50 years since Viking 1's historic first, which opened our eyes to the Martian surface. And NASA has kept improving technologies and exploring further on Mars ever since. Agency rovers began scouring the planet's surface in the 1990s, so we have gathered data on the planet's surface for decades upon decades at this point.

But in 1976, no one had ever seen the surface of Mars close up. This view was preceded by science fiction like Ray Bradbury's "The Martian Chronicles," which painted fantastical possibilities about what it might really be like on Mars. With Viking 1's view, we finally got some concrete evidence of the reality on the planet.

In 50 years, our understanding of Mars, our solar system and beyond has grown tremendously. But with each major accomplishment, we can look back at previous milestones such as this to see the stepping stones that paved the way to get us there.

Swelling from a razor-thin crescent into a cratered world before fading back into the darkness, Mars gave NASA's Psyche spacecraft both a spectacular view — and a 1,000-mph boost toward its namesake asteroid.

A new time-lapse video released by NASA, stitched from images taken throughout May, captures the probe's month-long encounter with Mars. On May 15, Psyche swooped within 2,864 miles (4,609 kilometers) of the surface, using the planet's gravity to boost its speed and adjust its trajectory toward asteroid Psyche, a metal-rich world in the main asteroid belt between Mars and Jupiter that the spacecraft is scheduled to reach in 2029.

"This gravity assist was years in the making, and the navigation team nailed it — Psyche flew by Mars on exactly the trajectory we needed to set us on a path to rendezvous with the asteroid in the summer of 2029," Bob Mase, Psyche's project manager at NASA's Jet Propulsion Laboratory in California, said in a statement.

Approaching from a steep or what scientists call a "high phase" angle relative to the sun, Psyche initially caught Mars as a slender crescent with just 4 percent of its disk illuminated and its thin atmosphere glowing in scattered sunlight, Hannah Zigo, a Psyche team member at the Arizona State University, said in a NASA video accompanying the statement.

As the spacecraft closed in, the video follows Mars steadily expanding to reveal numerous craters puncturing its surface, the ancient double-ringed Huygens crater and the south polar ice cap before receding in the spacecraft's rearview.

The flyby served a dual purpose. By aiming Psyche's suite of instruments at a well-studied world, engineers say they calibrated and validated the spacecraft's scientific payload ahead of its 2029 destination.

"We didn't anticipate big discoveries, given how extensively the planet has been studied," Lindy Elkins-Tanton, principal investigator for the Psyche mission at the University of California, Berkeley, said in the statement, "but we did complement Mars science with the data we collected through Psyche's unique perspective."

All three of the spacecraft's science instruments performed as expected, according to NASA. Its gamma-ray and neutron spectrometer, designed to determine the asteroid's elemental makeup, detected the predicted surge of escaping neutrons during closest approach, confirming its operational readiness.

The mission's magnetometer, which will search for evidence that asteroid Psyche is the metallic core of an early planetesimal, recorded its first magnetic signature from a planetary body since its launch in 2023, detecting the bow shock where the solar wind meets Mars' magnetic environment.

Psyche's twin multispectral cameras also passed their calibration tests, capturing the frames for the time-lapse while spotting Mars' tiny moons, Phobos and Deimos, from a distance, the NASA statement read.

Spotting the moons served as "a practice for the satellite search that we'll use at the asteroid Psyche to look for any moonlets there," Jim Bell, a planetary scientist at Arizona State University who leads the multispectral imager instrument team, said in the statement.

With Mars in its rearview and its instruments fully vetted, Psyche remains locked on course for its summer 2029 rendezvous with the metal asteroid.

"The spacecraft is in great shape, and we're on schedule to resume sustained thrusting with the solar-electric propulsion system later this fall," Mase said.

An amateur astronomer's plans for a camping vacation two years ago transformed into a possible crater find in Canada's north.

Amateur astronomer Joël Lapointe, using Google Maps to figure out his route for the 2024 vacation, saw some odd terrain in Quebec's Côte-Nord region centered on Lake Marsal. Lapointe suspected it was an impact crater from a meteorite, and made a report on Impact Earth — a crowdsourcing website for craters with Canada's Western University in London, Ontario near Toronto. Western planetary geologist Gordon Osinski made a visit to the region in 2025, provisionally not only confirming the crater, but saying it's probably one of the biggest discovered in recent years. The 390-million-year old feature is roughly 15 miles (25 kilometers) wide.

In an email interview with Space.com while on travel in Scotland, Osinski — known as "Oz" by the space community — said to his knowledge the last discovery of that scale was the approximately 31-km (19-mile) Hiawatha structure, also possibly a crater, spotted in Greenland in 2018. "However, that structure is completely buried by ice, so its diameter is uncertain and there is still some controversy about its origin," Oz said.

But in the case of the new crater, called Uhackatik with approval from the Innu Council of Ekuanitshit in whose traditional lands the crater lies, there is no doubt at all where the crater came from. Oz's expedition to the area revealed "shock metamorphic effects", which are deformations to the rocks induced by the shock waves and heating produced by a meteorite impact.

"Impact melt rocks are like they sound: large volumes of rock that are melted by the impact event, but then cool and crystallize to look a lot like volcanic rocks," he said. "Finding these preserved — as they are usually some of the first parts of a crater to be eroded — was a big surprise."

While most of the features are microscopic, Oz said in the field he and his collaborators could easily see "shatter cones", which are branching features in rock layers produced by the shockwave of impact. The research is not yet peer-reviewed, but it will be presented at the 88th Annual Meeting of the Meteoritical Society in Frankfurt, Germany in August.

While 400-million-year-old impact craters on Earth are hard to find, as geologic activity as well as erosion change their features over time, the precious evidence is helpful for scientists to better understand meteorite impacts on the moon, Mars and other rocky extraterrestrial bodies.

In terms of age, Oz noted, the moon's prominent Tycho crater best represents what Uhackatik probably looked like 390 million years ago. But On Earth, one of the best comparisons to Uhackatik is a moon-like crater used to help the Artemis II astronauts get ready for their moon mission this year.

That Earth crater is called Kamestastin (also known as Mistastin) in northern Labrador, Canada. Oz regularly runs expeditions there in consultation with the Mushuau Innu First Nation, as the crater lies within their traditional hunting grounds. Kamestastin includes anorthosite, a common mineral found in craters at the moon's south pole, where NASA hopes to land astronauts under the US-led Artemis program.

Artemis II astronauts Jeremy Hansen (from the Canadian Space Agency or CSA) and Christina Koch (NASA), as well as CSA backup astronaut and lunar-flyby capcom Jenni Gibbons, did an expedition to Kamestastin crater in 2023 alongside Oz and collaborators.

"For comparative craters [to Uhackatik], Kamestastin is actually a great one as the size is very similar," Oz said. "Kamestastin is well-preserved and I've worked there a lot … so in my mind, I was using Kamestastin as a template for exploring this new potential crater."

To fully confirm Uhackatik's extraterrestrial origin, Oz and collaborators are examining samples microscopically for more evidence of shock effects, such as chemistry indicating a high-temperature melt, or deformation effects in the quartz. In the meantime, Oz's lunar work with NASA continues: he will be part of the geology teams supporting the moon-landing astronauts during the Artemis 4 and 5 missions, which will touch down as soon as 2028.

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.

NASA's Curiosity rover has uncovered evidence of ancient sandstorms on the Red Planet.

What is it?

Scientists think ancient Mars was quite different than it is today. While we might know it now as a barred, reddish wasteland, billions of years ago it actually had an atmosphere. Scientists even think that it had flowing rivers and expansive lakes.

And with observations from the Curiosity rover, researchers are exploring ancient sandstorms they think blew across the Martian landscape.

In this image Curiosity snapped, you can see what experts think is the aftermath of an especially extreme sandstorm in a spot nicknamed "Jawbone Canyon." Winds from this storm were likely so extreme that they pushed sand into rippling waves that eventually hardened into rock.

And if you really look closely at this image, you can almost see how the rocks appear to have ripples on them.

While the image was captured in 2024, a new investigation of the observation and discovery of this sandstorm was described in a study published this year in the journal Geology.

Why is it incredible?

This observation by Curiosity is part of a long history of exploration on the Martian surface that actually began 50 years ago today.

On July 20, 1976, NASA's Viking 1 lander touched down on the Red Planet. Aside from the Soviet Mars 3 lander that lasted only a few seconds on the world before losing contact, Viking 1 was the first Mars lander to survive landing and successfully went on to study the planet.

Viking-1 took the first-ever images on the surface of Mars, studied the planet's soil and really sparked investigation of whether or not the world may have ever supported life. Thanks to the success of this mission 50 years ago, today we have rovers like Curiosity and Perseverance on Mars leading us at the cutting edge of exploration.

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."

If you still picture Mars as a monotonous red desert, it may be time for an update.

The European Space Agency's Mars Express orbiter has been capturing some of the Red Planet's most surreal landscapes, and its latest images reveal a sprawling field that looks like molten metal frozen across the floor of an ancient Mars crater.

The shimmering "waves" aren't metal at all, however. They are dark sand dunes dusted with seasonal frost, much of it carbon dioxide, or "dry ice," that settles on the surface during Martian winters, giving the dunes their uncanny chrome-like sheen, according to ESA.

The rest is a trick of light and contrast. Because the dark sand absorbs light and the white frost reflects it, the interplay transforms the landscape into something that looks more like a scene from a sci-fi movie than a windswept Martian plain.

Over thousands of years, Martian winds have sculpted this volcanic sand into dunes that now ripple through the floor of Kaiser Crater, a 129-mile-wide (207-kilometer-wide) impact basin in the planet's southern highlands. The bowl-shaped crater acts as a giant sand trap that prevents the sand from escaping, according to NASA.

The dunes themselves are darker than much of Mars' surface because they are made of fine, basaltic sand rich in volcanic minerals such as pyroxene and olivine, rather than the iron-oxide dust that gives the planet its familiar rusty-red appearance and its famous moniker, the Red Planet.

Because the crater floor remains visible between the ridges, scientists think there is a relatively limited sand supply shaping the field. Still, these ripples of sand are massive, extending for several kilometers and towering more than 100 meters (320 feet) above the surrounding terrain.

The landscape isn't just visually dramatic, it also preserves clues to a time when Mars was a very different world.

Today, Mars is wrapped in an atmosphere little more than a thin veil that is 100 times thinner than Earth's and slowly leaking into space. That makes it harder for winds to lift and transport sand than it is on our own planet. Yet the soaring dunes inside Kaiser Crater show that Martian winds have nonetheless been powerful enough to sculpt vast landscapes over time, perhaps during a period when the Martian atmosphere was thicker a few billion years ago.

The new image adds to a growing collection of striking Martian scenes captured by Mars Express, which has been orbiting the Red Planet since 2003. Just last month, the probe tracked a frenetic cluster of 30 dust devils swirling through the canyons of Mamers Valles, also in the northern hemisphere.

Over the spring and summer, the orbiter similarly spotlighted the planet's vast and complex geological history, from Shalbatana Vallis — carved by groundwater floods about 3.5 billion years ago into winding valleys that span the length of Italy — to a massive blanket of dark volcanic ash elsewhere on the world that has spread across a large chunk of the terrain over just the last 50 years, having either been redistributed by Martian winds or exposed as the overlying dust was blown away.

However desolate Mars may appear from afar, there is certainly no shortage of activity on its surface — or discoveries still waiting to be made.

The wildfires tearing across Canada are so extreme that the smoke billowing upward can be seen from space.

What is it?

Over 850 wildfires are currently devastating Canada, as reported by the Canadian Interagency Forest Fire Center. The fires are spreading across Manitoba, Saskatchewan and Ontario; most remain completely uncontrolled.

In addition to the immense destruction caused by the fires themselves, the smoke from these fires is causing serious concerns about dangerously poor air quality all across Canada and even in the northeastern United States. As far as New York, the air quality on Thursday (July 16) was labeled "very unhealthy" after the state activated emergency air quality protocols.

The smoke is so expansive it's clearly visible in this image captured on July 14 from Earth orbit.

Why is it noteworthy?

Studying wildfires and wildfire smoke from orbit can give us a bigger picture view of these catastrophic event. This data is important for disaster relief in the short term — but also in the long-term. With climate change continuing to progress due to human activities like burning coal for cheap power, we can expect natural disasters to worsen. Among the many effects of climate change, this includes longer and more intense wildfire seasons, especially in regions that are already susceptible to fire such as these regions across Canada.

The new image was captured by the NOAA-21 satellite with the instrument VIIRS (Visible Infrared Imagine Radiometer Suite). You can see massive plumes of smoke over southeastern Canada treading into the northeastern U.S. Thick smoke covers swaths of Canada's landscape and wisps of smoke trail all the way down through New York and across the U.S.

Most of this smoke, at least the smoke we can see in this satellite image, is coming from wildfires in northwestern Ontario. As the wildfires continue to burn, satellites like NOAA-21 will be keeping watch.

The most powerful solar storms to strike Earth may pack a bigger punch than scientists realized, according to a new study that suggests the impacts of extreme space weather have been underestimated.

Researchers found evidence that the apparent upper limit on Earth's response to the strongest solar storms may be an artifact of how solar wind has been measured rather than a true physical ceiling. If confirmed, the findings suggest that rare "once-in-a-thousand-year" geomagnetic storms could have a greater impact on modern technology than current estimates indicate, according to a statement.

"Our planet's magnetic field does a really great job of protecting us against many space weather effects and so they often just show up as glitches or beautiful aurora," Maria Walach, co-author of the study from Lancaster University, said in the statement. "There are however extreme cases."

Solar storms occur when eruptions from the sun, such as coronal mass ejections and solar flares, send clouds of charged particles hurtling toward Earth. While they can produce spectacular auroras, they can also disrupt satellites, GPS, radio communications and power grids.

History has shown the damage even less extreme storms can cause. The 1859 Carrington Event, the strongest geomagnetic storm on record, disrupted telegraph systems around the world and pushed auroras from their usual high-latitude skies near the Arctic and Antarctic to locations as far south as the tropics. Another powerful storm in 1989 collapsed Quebec's power grid, leaving millions without electricity, while the 2003 "Halloween storms" disrupted satellites, GPS and radio communications.

While the study doesn't suggest that an unprecedented solar storm is imminent, it argues that scientists may need to rethink how they estimate the severity of the rarest events — an increasingly important challenge as modern society grows more dependent on satellites and other vulnerable technologies.

The researchers traced the apparent upper limit to where most solar wind measurements are collected. Many observations of extreme events come from spacecraft near the Sun-Earth Lagrange Point 1 (L1), about 1 million miles (1.5 million kilometers) upstream of Earth. Because the strongest solar wind tends to weaken somewhat before reaching Earth, comparing L1 measurements with conditions at our planet can make it appear that Earth's upper atmosphere stops responding to increasingly intense solar wind, even when it does not.

To test that idea, the team analyzed more than one million solar wind measurements collected by NASA spacecraft orbiting much closer to Earth, where the solar wind directly interacts with our planet's magnetic field. Those observations showed that electrical currents flowing through Earth's upper atmosphere continued to increase alongside stronger solar wind, with no sign of the previously assumed upper limit. The results suggest that exceptionally powerful solar storms could generate stronger geomagnetic disturbances — and greater impacts on satellites, communications systems and power grids — than earlier estimates predicted.

"Fortunately, these very extreme cases are rare, but this also means we have limited data to work with and only time will tell what happens at the very extreme one-in-a-thousand-year kind of event," Walach said in the statement.

The study comes as the sun remains near the peak of its roughly 11-year solar cycle, known as solar maximum, when sunspots, solar flares and coronal mass ejections become more frequent. During the current cycle, strong geomagnetic storms have repeatedly sent auroras far beyond their usual polar skies.

In May 2024, the strongest geomagnetic storm in more than two decades illuminated skies across much of the United States and Europe while causing intermittent disruptions to high-frequency radio communications, GPS-guided equipment and some satellite operations. Although significant, that event was far less powerful than the Carrington Event — or the even rarer storms the new study suggests may be possible.

The findings were published July 15 in the journal Nature.

The aftermath of landslides have been found in images of Pluto's surface taken when the New Horizons mission flew past the dwarf planet in 2015. The landslides are evidence that the icy world is still active, albeit on geological timescales.

A team led by geologist Marco Emanuele Discenza pored over images taken by New Horizons' LORRI (Long-Range Reconnaissance Imager) instrument, which was capable of detecting surface features as small as 984 feet (300 meters). They found convincing evidence for six landslides in total that have taken place down the inner walls of three craters on the western edge of Sputnik Planitia, the heart-shaped feature that characterizes Pluto's appearance.

Previously, geological features left behind by landslides have been found on a host of bodies in the solar system, including Mars, Ceres in the asteroid belt, some of the icy moons of the gas giants, and even Pluto's companion, Charon. However, these are the first to be found on Pluto.

A landslide that fell 1.4 miles (2.2 kilometers) was identified in Pluto's Coughlin crater, close to a secondary crater on Coughlin's rim that may have triggered the landslide in the first place. Two further landslide features were seen in Giclas crater, and another three were spotted in a third, unnamed, crater.

The landslides were identifiable by their large debris aprons that spilled out onto the crater floors, the distance the landslide material travelled ranging being between 6.3 and 9 miles (10.1 and 14.5 km). Some of these debris aprons appeared bumpy, as if they contain large boulders of solid ice, while the areas around the source of the landslides feature well-defined, concave-shaped cliffs where material has broken away and tumbled down the craters' steep walls.

The great lengths that the debris rolled means that Pluto's landslides are among the most mobile in the solar system, a product of low gravity and low-friction icy rubble. The largest of the debris aprons covers 50 square miles (130 square kilometers), which would be large enough to bury a small city or a large town.

Landslides are important processes in shaping planetary surfaces, enabling the transport of material across great distances. The trigger for Pluto's landslides, however, is not yet clear. While the landslide in Coughlin appears to have been caused by a smaller impact nearby, the other five have less certain origins. One possibility is thermal stresses in the surface ice caused by the slight temperature changes that cause Pluto's volatile materials – among them molecular nitrogen, carbon monoxide and methane – to periodically sublimate and then condense again. These temperature changes are the result of Pluto subtly heating up and cooling down as its elliptical orbit brings it slightly closer to the sun, crossing inside Neptune's orbit, and then moving farther away again.

There is also evidence for more landslides in other craters, but New Horizons' coverage of Pluto's surface was limited as it hurriedly flew past on July 4, 2015, and the imagery required to confirm these other landslides is lacking.

The findings were published in the journal Icarus.

Towering glaciers flow down the Himalayas' northern slopes like icy giants cascading onto China's Tibetan Plateau.

What is it?

Back in May, from aboard the International Space Station 259 miles (417 kilometers) above Earth, NASA astronaut Jessica Meir peered out the station's windows with her camera and captured a breathtaking sight.

In that fleeting moment from space, she captured the northern slopes of the Himalaya mountains stretching into China. And atop the mountains, slow-moving rivers of glacial ice carve their way downhill.

This view shows the enormity of this mountain range, which separates Nepal from China's Tibetan Plateau. The Himalayas have the highest mountains in the world, including Mount Everest, with over 110 mountain peaks surpassing 24,000 feet (7,300 meters) of elevation above sea level. Ranging across five countries (Nepal, India, China, Bhutan and Pakistan) the mountain range is about 1,500 miles (2,400 kilometers) wide.

Why is it incredible?

With the range being so incredibly expansive, this view from space offers a unique vantage point from which we can see a large swath of the mountains in motion. Even in a helicopter, you would get a fairly localized view of individual mountains in the Himalayas. This view provides a striking scene that you cannot see from the surface of our planet.

This view is also a reminder of how important space is in our evolving understanding of climate change. As our planet continues to change and sea levels rise with warming temperatures, we can see glacial movement from space. This is an important resource to researchers fighting to better understand climate change so we can better fight it. With access to information about glaciers and how they melt, move and flow across the world, we can be better prepared to protect our planet and its inhabitants.

NASA's Curiosity rover has spotted a strange honeycomb texture on the surface of Mars. But what is it?

What is it?

Almost 14 years since landing on the Red Planet, Curiosity is still hard at work exploring. And in new observations, Curiosity has revealed an image that is certainly ... peculiar.

Curiosity went to get a closer look at an area first observed from Mars orbit, and found what appears to be a honeycomb structure in on the planet's surface. Polygonal shapes, nearly identical to one another, make up a pattern almost like a Martian wallpaper or carpet.

But what is it? Why does it look like that? What is a honeycomb doing on Mars?

Why is it incredible?

This is one of many mysteries we have yet to solve on Mars. While the team saw this area first from orbit around the planet, when the rover arrived and saw this structure they were surprised, they shared in a blog post.

In addition to the honeycomb texture, the area was littered with dark rocks and strewn around. But even these pebbles lack explanation. Did they "float" down from higher rock levels, did they launch out of Gale crater during some ancient collision or could they possibly even be meteorites from outside of Mars that ended up strewn across the surface? Researchers think any one of these explanations could be possible.

Previous, similar dark stones have been found on Mars with minerals like nickel that are common in meteorites and uncommon in Mars rocks. But are these similar? Perhaps part of a similar collision event? We don't yet know.

As researchers find new mysteries on Mars, they also continue to find new ways to investigate the unknown. With further study, they will explore both these strange honeycombs and the dark rocks scattered amongst them.

Landing spacecraft on the moon could contaminate ancient clues about how life may have originated on Earth, a new study finds.

As NASA continues on with its plan of sending astronauts back to the moon with the Artemis program, researchers are exploring what possible unintended consequences may arise from humans visiting the lunar surface. For instance, Artemis IV will land astronauts near the moon's south pole and the agency has future plans for building a longer-term moon base on the lunar surface, which would require many more trips. And indeed, a new study has found the exhaust from spacecraft involved with these landings could expel enough methane to contaminate the moon's surface — possibly destroying molecules that could help to explain how life may have originated on Earth.

"We are trying to protect science and our investment in space," senior study author Silvio Sinibaldi, the planetary protection officer at the European Space Agency, said in a statement. "Our activity can actually hinder scientific exploration."

While experts have had concerns for some time about how rocket launches on Earth pollute our planet and atmosphere, scientists have only really considered this issue with our own planet. This is especially because we haven't been to the moon's surface in over 50 years; concerns of accidental effects of a lunar landing simply haven't been top-of-mind. That's what makes this new study so important. It points to a potential issue that could mean that future moon landings might actually be detrimental to science.

Life's clues on the moon?

So why do we think the signs of life could be hiding on the moon? It's actually hiding in ice. Dark craters near the moon's poles, which exist in perpetual shadow, hold ancient ice. This ice is thought to contain material from asteroids and comets that smashed into the moon billions of years ago. Trapped in lunar ice to this day, these bits of ancient collisions could include what the researchers describe as "prebiotic organic molecules," or molecules that could have preceded life on Earth.

It's thought that these molecules from asteroid and comet visitors could have sparked life on Earth, and by studying those possibly trapped on the moon, researchers could be looking at the molecules that ended up combining and creating life as we know it.

The molecular history of life on Earth is pretty much nonexistent on our own planet, as it was largely destroyed by the billions of years of changes we've experienced. But the moon has remained mostly unchanged, so these wells of ice are a uniquely-preserved sampling of pre-life molecules.

"We know we have organic molecules in the solar system — in asteroids, for example," Sinibaldi said. "But how they came to perform specific functions like they do in biological matter is a gap we need to fill."

This ice exists in a somewhat fragile ecosystem, so left alone in darkness, this ice isn't going anywhere anytime soon. But with Artemis, NASA is planning on sending crewed landers to the moon's south pole. That might pose a problem. With computer models in this new study, researchers have shown that the methane exhaust from these landers could very quickly and permanently contaminate this ancient ice, destroying the molecular evidence sealed within.

Inside the simulations

In those computer models, the researchers simulated how methane, the main organic component expelled by planned lunar landers, would spread across the moon's surface after a landing at the south pole. While the simulations included the effects of solar wind and radiation, the moon's lack of an atmosphere caused the methane to spread incredibly quickly, reaching the moon's north pole in under two lunar days.

Within one lunar week (which is roughly seven months on Earth), over half the methane was trapped at the moon's cold polar areas, with a whopping 42% of the substance trapped at the south pole compared to 12% at the north pole. This methane could collect in the same cold pockets where ice and ancient molecules have been collected for billions of years, possibly contaminating this finite, scientific evidence.

"Their trajectories are basically ballistic," lead author Francisca Paiva, a physicist at Instituto Superior Técnico in Portugal, said in the statement. "They just hop around from one point to another."

In better news, there may be a way to circumvent some of this methane disturbance. For instance, the study suggests it's possible that by choosing colder landing sites, scientists can avoid having the methane travel as quickly or as far. Additional simulations are needed to better understand how exhaust compounds travel on the moon, however, as well as the risks that this poses for scientific investigations and if there are other materials lunar trips will involve that could contaminate the environment. Above all, the new study's team emphasizes that as we push toward future lunar exploration, it is key to balance our dreams of settling the moon with preserving its priceless history.

"We have laws regulating contamination of Earth environments like Antarctica and national parks," Paiva said. "I think the moon is an environment as valuable as those."

This work was described in a study published last year in the journal the American Geophysical Union.

Environmental and scientific organizations are banding together to demand federal environmental reviews of space-based data center projects, which plan to put more than a million new satellites in Earth orbit over the coming years.

Over the last few months, a number of different companies have requested licenses from the U.S. Federal Communications Commission (FCC) to launch data centers into space. SpaceX's proposal alone requests licenses for up to one million satellites in low Earth orbit (LEO). But the requested licenses don't come with any environmental review of the impacts that the satellites — especially collectively — could have on dark skies, wildlife or our atmosphere. In response, a coalition of environmental and scientific organizations represented by the environmental nonprofit Earthjustice have petitioned the FCC for this review.

"Allowing a million orbiting data centers with no environmental review isn’t just irresponsible — it’s reckless," Tim Whitehouse, executive director of Public Employees for Environmental Responsibility, said in a statement on Wednesday (July 8). "The potential for these projects to degrade the atmosphere with pollution and debris and harm wildlife needs to be carefully considered before licensing these projects."

Space is big, but a million new satellites added to LEO to support space-based data centers would be a massive increase. Currently, just Earth orbit harbors just 15,000 active satellites and 46,000 tracked objects overall. This number was already on track to grow to 58,000 active satellites, thanks in large part to SpaceX's ever-growing Starlink broadband megoconstellation, but the data-center plans could make it absolutely explode.

Experts suggest that this significant addition to the technological ecosystem in orbit could have disastrous consequences for life on Earth.

"Drastically expanding satellites in space has a direct impact on people’s everyday lives as well as the future of our planet," Jan Hasselman, senior attorney at Earthjustice, said in the statement. "Agencies that authorize companies looking to space as the next frontier still must operate within the law, and the law requires the FCC to consider all the risks and impacts of these proposals. If we have to sue so that they comply, we will."

The FCC has not yet required any environmental review for satellite companies seeking authorization to deploy in LEO. With its new petition, this coalition aims to change that, asking the FCC to stop granting licenses for orbiting data centers without an environmental review.

What possible environmental harms are they worried about? First of all, as more and more satellites are added to the orbital population, the greater chance there is of collisions, which could produce debris that not only clutters Earth orbit but also increases the risk of additional collisions.

Further the rocket launches that propel the satellites to orbit contribute greenhouse gas emissions to our atmosphere. And the spacecraft cause further pollution when they deorbit, releasing heavy metals and other materials when they burn up in Earth's air.

In addition, a massive increase in satellites will fundamentally change the night sky. Light pollution is known to impact wildlife and ecosystems, disrupting natural rhythms and influencing everything from migration patterns to daily feeding schedules. These disruptions can push animals like bats to miss windows in which insect prey are available, causing them to starve. They can also prevent mountain lions — apex predators that uphold their local ecosystems — from roaming normally at night, fragmenting populations over time, according to the National Wildlife Federation.

The effects of light pollution on wildlife would doubtless grow if suddenly a million new, blinking satellites were added to our night skies. And issues with light pollution extend to our species as well, as life would look quite different if our night skies were much more crowded by bright lights.

"These projects could permanently alter the night sky as we know it," Ruskin Hartley, executive director of DarkSky International, said in the statement. "The FCC needs to take seriously its obligation to ensure these projects do not cause unnecessary harm to naturally dark skies, or to our overall environment."

If you look at this picture for too long, you might start to hear the waves lapping up against the shore or feel a salty breeze in the air.

You might not have a trip to the Bahamas planned, but you can always enjoy its beauty in this spectacular summertime snapshot captured by NASA astronaut Chris Williams from aboard the International Space Station.

What is it?

In a snapshot that looks straight out of a travel commercial, we can see the crests of rippling waves of sand peeking out from beneath turquoise waters off the coast of the island Eleuthera in the Bahamas.

The moment was captured 263 miles (423 kilometers) above Earth's Atlantic Ocean from aboard the space station orbiting our planet.

This isn't the first fun snapshot captured by Williams who also recently flexed his muscles for a photo mid-spacewalk.

Why is it incredible?

This photo is incredibly beautiful. That much is immediately obvious. And if you've ever swam in picturesque waters like this, then you know how calming and magical such places on Earth can be.

But this photo is more than just pretty, as it shows that we can see Earth's beauty from 263 miles away. It is a reminder that our planet is truly special. Imagine if a future mission saw beauty like this from space on a far off exoplanet, or even a planet outside of our solar system. Currently, our planet is the only one we know of with views like this, but it's possible that in the future we might find tropical shorelines and vacation vistas aren't exclusive to our home planet.

The success of NASA's future moon base depends in large part on mission design, which should allow astronauts to work together well in a way independent from psychological training, a new study asserts.

The goal of the study was to identify "specific conditions" for mission success and to look for any "red flags" that may stand in the way, lead investigator Anamaria Berea, a computational social scientist at George Mason University (GMU), told Space.com via email. (The first author of the PLOS ONE study, which was published in May, was GMU's Raymond Vera.)

The team conducted the research using agent-based models, which are tools for computational simulations in fields ranging from the study of bird flocks to the spread of disease, Berea said. While a lot of modern-day AI "trains" or "learns" to extrapolate from information provided in a data set, agent-based modeling instead uses a data set to "understand emergent phenomena that don't have one single cause or direct cause," she said.

The study team considered scenarios for how many astronauts would be on the moon base and how often resupply missions would occur. In an "initial case," for example, the assumed mission duration was three months, with a single resupply run at Month 2 with food, water, air and a fresh group of astronauts.

Using a complex probability analysis known as a Monte Carlo simulation, the model astronauts in this scenario showed a productivity rate of about 20% against their expected tasks, "which is acceptable for a typical manufacturing process," the authors noted.

This productivity rate doesn't take into account anything unexpected that may crop up during the mission, the authors added. "The low task completion rate suggests that, on average, teams are having challenges to overcoming psychological stressors and environmental disruptions," they wrote.

Lessons from the International Space Station

NASA tracks productivity a little differently on the International Space Station (ISS). The agency uses a metric called "utilization," which largely refers to the amount of crew time and number of scientific investigations that are performed on the space station during an increment or expedition. As of 2014, the ISS program suggested that ideal utilization should be 35 hours per crew per week when there are three people working on the U.S. part of the space station, and 68.5 hours if there are four or more. (The Russian side of the ISS works largely independently in this respect.)

"NASA has generally met or exceeded this goal and set a high of 120 average hours per week devoted to research from October 2019 to April 2020," NASA's Office of the Inspector General (OIG), which has been tracking all of these productivity figures, stated in a report published in September 2024.

"Starting March 2022 through March 2023, the latest published data, we have seen utilization near 90 hours per week," the OIG noted. "In addition to the hours spent per week on research, the number of scientific investigations performed on-orbit has increased."

Figure 1 of the OIG report also shows both crew time and scientific investigations increasing, as a trend, between 2000 and 2023, suggesting that utilization of the space station is continuing to grow. And this is despite periodic and documented disruptions that required astronauts to take a step back from being productive, such as emergency ammonia leaks requiring spacewalks, the 9/11 disaster, or sheltering in place during brief contingencies such as space debris passing within a few miles of the station.

Not all crew time can be used for utilization even if all goes well, however, as the station requires normal maintenance like cleaning, and astronauts also need daily time for sleep, meals and a little relaxation. Additionally, utilization tends to increase with larger crews on the space station compared with smaller ones, as maintenance becomes less of a burden with more hands to take on these tasks.

But "lack of redundancy" in key supply items to the space station does pose a risk to utilization, the OIG has noted. As just one example, SpaceX Crew Dragon capsules and Roscosmos Soyuz spacecraft are the only two vehicles that bring astronauts to the station right now. "The lack of redundancy and limited capabilities of both cargo and crew transportation increase the risk to NASA's current and future ability to bring critical supplies, science, and crew to and from the station to maintain safe operations and full utilization of the ISS," the OIG wrote in the report.

Isolated environments

Those of us who have been on long car rides in a group, or who remember being in tight quarters with roommates or family during the pandemic, have some idea of what an isolated, confined environment (ICE) feels like: crowded, with limited resources, and possessing few connections with the outside world. Space serves as just one example of a true ICE; isolated research bases (like in Antarctica) or submarines have also been studied in the literature, according to a separate 2021 study in the journal Neuroscience & Biobehavioral Reviews.

Put simply, ICE refers to a location where humans must work to a high standard in isolated and often dangerous circumstances, with only long-distance support (if possible) from a mission control or its equivalent. And, as the new study points out, a moon base would be a complex example of an isolated environment — one featuring not only resident astronauts but also rovers, other robots and occasional visiting crews.

"The premise for our modeling approach came from trying to understand better the human factors involved in crewed space missions, particularly the deep-space ones, for which we don't have a lot of historical data," Berea said.

That's because only a handful of people have traveled beyond low Earth orbit — the two dozen who flew to lunar realms on Apollo missions in the late 1960s and early 1970s, and the four astronauts of NASA's Artemis 2 flight around the moon this past April.

"We ran various scenarios of space mission durations, number of astronauts, potentially unforeseen circumstances that can happen on the lunar surface or the habitat," she said. The model suggested the missions with the highest probability of success would include six astronauts working on the moon at a time, with fresh supplies coming from Earth every two weeks, and no extreme fluctuations in the environment from things like radiation or a micrometeorite impact.

"In contrast, the worst-case scenario consists of four astronauts on the moon at one time, only one month resupply window between Earth and moon, and moderate to high adverse environmental probabilities," Berea said. And, when asked if training is a factor in mitigating adverse effects, she did not necessarily agree that the years of work NASA and other agency astronauts put in would be more effective than shorter-duration training used for moon base analogs.

"People can be very, very well trained, but for long-duration or deep-space missions, there will always be a human factor involved," she said. "We looked at combinations of skills and personalities in a team of astronauts, and there is a fine line between having a team that is too small and a team that is too large, and there are synergies and emergent behaviors that come from people interacting with each other and with their environment.

"The team is more than the sum of its people," she continued. "The best ways to overcome these is not by more training, but by fine-tuning other aspects of the missions: the duration of the mission, the frequency of resupply missions, and the contingency plans for accidents and unforeseen conditions in extreme environments."

NASA, however, puts its ISS crews through many years of remote environment training long before they float through the space station hatch — and Artemis 2 commander Reid Wiseman told The New Yorker that extensive psychosocial training led to the obvious closeness seen live among his own four lunar crewmates despite tight quarters (and vent line issues that led to occasional toilet trouble).

That psychological intervention during training was by design. "Preparation starts by recruiting mentally healthy people and then providing training to help them deal with potential situations and issues," wrote the Canadian Space Agency of this training, citing NASA protocols. "Astronauts repeat this training often enough that they can anticipate their own reactions and those of their teammates. They also receive constant support from teams on the ground and have access to a variety of tools to help them deal with potentially difficult situations."

Berea noted, however, that psychology forms a part (but is not the focus) of her teams' simulation, including considering NASA TLX (task load index) scores and data, which measures coping and stress for astronauts. The researchers also considered case studies from analogs including Antarctic research missions and time aboard submarines or oil rigs, as some examples.

"We need to pay attention not only to the astronauts, but the team as a whole, and each team and space mission are unique. We will not be able to model these with statistics or AI," she said. "But what we can do is to make sure that before we send any human to live and work on the moon, that we understand well the complexity of interactions and scenarios they will face during the mission, and we can help with that."

NASA's New Horizons probe has woken up in good health nearly 6 billion miles away beyond Pluto after spending nearly a year in hibernation.

Traveling such vast distances between our solar system's most remote objects means New Horizons often cruises for months at a time with little to do other than passively collect data. During these periods, the probe goes into a hibernation mode in which its instruments still collect data, but most other systems power down.

New Horizons entered just such a hibernation period last August, and has now woken up in "good health", according to a NASA statement. The spacecraft is 5.9 billion miles (9.5 billion kilometers) from Earth, so far away that it takes around 9 hours for its radio signals to reach us. Now that it's awake, New Horizons will begin transmitting the data it has collected over the last 321 days and letting its controllers on the ground know how its systems are faring in the cold, dark reaches of deep space.

So far, the probe appears to be in perfect health. "Every status report through this hibernation period was 'green,' meaning all was well aboard New Horizons each and every week," said Alice Bowman, the New Horizons mission operations manager at the Johns Hopkins Applied Physics Laboratory (APL) in the NASA statement.

New Horizons is the first and only flyby spacecraft to conduct a flyby of the Pluto system, which it did in 2015. Four years later, the plucky probe studied the most distant object ever explored in our solar system, the snowman-shaped planetesimal Arrokoth, while it was one billion miles (1.6 billion kilometers) past Pluto.

Since then, the long-distance voyager has been probing the edge of our sun's influence and studying objects in the Kuiper Belt, the cold, donut-shaped ring of icy objects that circles the outer solar system beyond Neptune.

New Horizons is currently speeding away from Earth at a rate of 300 million miles (483 million km) per year, according to NASA.

Three weeks from now, New Horizons will begin conducting a study of hydrogen in the outer heliosphere, the region of space influenced by the stream of charged particles blowing outward from the sun, known as the solar wind.

The data the probe is collecting at the farthest reaches of our solar system is the first of its kind. It could help scientists understand what happens at the boundary between the sun's region of influence and interstellar space, known as the "termination shock."

Only two spacecraft have crossed this boundary before, NASA's twin Voyager probes. However, those far-flung explorers weren't equipped with the same scientific instruments as New Horizons, which enable it to conduct more sensitive measurements of this distant region of the solar system.

"The data from the termination shock encounter will be a treasure trove for space physicists worldwide who are eager to understand how this vast boundary works," Pontus Brandt, New Horizons project scientist at APL, previously told Space.com. "All these discoveries from pioneering missions like Voyager and New Horizons teach us how little we know about what lies beyond."

For decades, astronomers have debated whether Earth's fate was tied to the sun's. When the star exhausts the hydrogen fuel that powers it about 5 billion years, it will swell into a red giant large enough to engulf Mercury and Venus — and, several studies have suggested, Earth as well.

New research, however, suggests our planet has a better chance of escaping that fiery end than previously thought. Using updated models of how aging stars interact with their planets, researchers found that the gravitational forces drawing Earth toward the expanding sun are weaker than older models predicted. That would give the planet more time to drift outward as the dying sun sheds its outer layers into space, potentially avoiding engulfment altogether.

The finding does not guarantee Earth's survival. Instead, researchers say it shifts the biggest uncertainty from how strongly the expanding sun tugs on planets to the poorly understood variable of how much mass the star will lose during its final stages of evolution.

"The largest uncertainty no longer comes from the tidal calculations, but from how much mass the future sun will lose," study lead author Mats Esseldeurs of the KU Leuven's Institute of Astronomy in Belgium said in a statement. "Observations of sun-like giant stars currently point towards Earth's survival, but we need better observations before we can be certain."

When stars like the sun exhaust their core hydrogen and balloon into massive red giants, they trigger a cosmic tug-of-war between expanding tidal forces pulling planets inward and shedding stellar weight pushing them outward, which ultimately decides whether nearby worlds are engulfed or saved.

This planetary push-and-pull unfolds in two stages. As the sun expands, gravitational tides act like a subtle brake, slowly draining Earth's orbital energy and pulling the planet inward. At the same time, the dying star sheds vast amounts of gas through powerful stellar winds, eventually losing about half its mass. As the sun grows lighter, its gravitational grip weakens, pushing the surviving planets outward into a wider orbit that could double their distance from the star, according to NASA.

"The fate of Earth depends on a delicate balance between these two effects," Esseldeurs said in the statement. "If tidal interactions dominate, Earth is engulfed. If mass loss dominates, Earth escapes to a wider orbit."

Previous studies reached different conclusions mostly because they treated those competing processes differently, Esseldeurs and his team argue. A few of those studies neglected tidal interactions altogether, while others relied on simplified prescriptions developed decades ago that predicted a much stronger inward pull, according to the study.

Instead of relying on those older formulas, the new study uses updated calculations of tidal forces based on the shifting internal structure and dynamics of aging stars — which the team says allowed it to precisely account for both tidal friction and shifting stellar winds — before testing the results against a range of possible mass-loss rates for the sun's final giant phase.

The results suggest that even with the weaker inward gravitational pull, Mercury and Venus are unable to outpace the expanding sun and are inevitably engulfed, while Earth and Mars migrate safely through both giant phases, leaving our planet to eventually settle into a broader orbit around the white dwarf remnant the sun will leave behind, the study found.

The picture is far from settled, however. Because astronomers still cannot precisely observe how rapidly sun-like stars lose mass late in life, "the ultimate fate of the Earth remains uncertain," the researchers write in the new paper.

By factoring in real-world mass-loss rates from L2 Pup — a red giant star roughly 183 light-years away that was used as a proxy for our future sun due to its similar mass — the researchers confirmed that Earth will drift outward just quickly enough to avoid being swallowed, tipping the scales toward survival over destruction, the study notes.

For us humans, the finding offers academic comfort rather than practical salvation. Most scientists agree that as the sun ages, it will steadily grow hotter, boiling Earth's oceans and rendering the planet completely uninhabitable in about 1 billion years, long before the sun begins to expand.

Yet even if humans aren't around to witness it, tracking Earth's ultimate survival provides important context for how planetary systems evolve as their stars age, a framework that researchers say will be further refined by future observations of dying, sun-like stars.

"This will enable us to conduct population studies of the planetary orbital evolution around evolved stars," the researchers wrote in the paper, "and help us to constrain the future evolution of the Earth-sun system."

The study was published in June in the journal Astronomy & Astrophysics.

The mystery of how the sun's corona, which is its outer atmosphere, reaches millions of degrees could have a surprising explanation: cosmic dust riding the magnetic waves carrying plasma on the solar wind.

"For decades, researchers have focused mainly on how electrons, ions, magnetic fields and plasma waves transport and dissipate energy in the solar atmosphere," said lead researcher Syed Ayaz of the University of Alabama in Huntsville in a statement. "Our work adds a new ingredient to this picture: dust grains."

The finding came courtesy of NASA's Parker Solar Probe, which has flown closer to the sun than any other spacecraft, skirting the corona at a distance of 6.1 million kilometers (3.8 million miles). If you've ever witnessed a total solar eclipse, or even seen a photograph of one, then you will be familiar with the corona — the ghostly tendrils of light that surround the eclipsed sun. Those tendrils are formed from plasma, or ionized gas, at temperatures in excess of a million degrees Fahrenheit, compared to the sun's visible surface, the photosphere, which radiates at about 9,932 degrees Fahrenheit (5,500 degrees Celsius). At those temperatures, the photosphere outshines the corona only because the plasma in the corona is so sparsely distributed. This is why the only time we can see the corona is during a total solar eclipse, when the photospheric glare is blocked.

Parker does not carry a cosmic dust detector, and that's because until now dust has not been considered a serious component of the solar atmosphere. Indeed, in the high temperatures of the solar corona it had been thought that dust could not survive for very long and would therefore have no impact.

However, Parker does host a bunch of antennas and magnetometers collectively referred to as the FIELDS experiment, designed to measure the electromagnetic field and radio emissions in the solar corona. The antennas kept picking up unexpected spikes in voltage, which according to Ayaz and his team are produced by clouds of charged particles created when tiny dust grains slam into Parker at high velocity.

These dust grains have accrued an electrostatic charge, which can interact with the electromagnetic field carried by the solar wind as it leaves the sun, which in turn can influence waves of plasma reverberating through that electromagnetic field called Alfvén waves.

There are two possible, competing ways in which dust can affect the Alfvén waves, which in turn could determine how energy is dumped into the corona, heating it. On one hand, the mass of the dust can act to provide extra inertia to the plasma as it rides the solar wind, allowing the plasma energy to be transported across wider distances. On the other hand, the electric charge on the dust grains can bolster the interactions between charged particles in the plasma, the Alfvén waves and the solar electromagnetic field.

"If dust mass dominates, [Alfvén] wave energy may travel farther into the corona," said Ayaz. "If dust-charge effects dominate, the energy may be released more locally as particle heating."

The balance between these two effects can therefore control where and when energy is deposited into the corona, focusing it in areas and causing temperatures there to rise dramatically.

Future solar missions are now going to have to start taking dust into account, said Ayaz, with dedicated detectors designed to measure dust's properties close to the Sun.

"The bigger question is fascinating," said Ayaz. "Is dust simply passing through the near-Sun environment, or is it helping shape how electromagnetic energy becomes heat and solar-wind motion?"

The new discovery was reported on July 1 in The Astrophysical Journal.

More evidence that the interstellar comet 3I/ATLAS is much older than our solar system has come to light, along with clues that it formed on the outskirts of the protoplanetary disk belonging to its parent star long ago.

Earlier this year, researchers led by Martin Cordiner of NASA's Goddard Space Flight Center revealed that data from the James Webb Space Telescope (JWST) suggested that 3I/ATLAS is between 10 and 12 billion years old, based on the ratios of its carbon and deuterium isotopes. This would make it more than twice the age of our 4.6-billion-year-old solar system. Now, new results from the Ultraviolet and Visual Echelle Spectrograph (UVES) on the European Southern Observatory's Very Large Telescope support the JWST observations of carbon isotopes, and also introduce measurements of nitrogen isotopes that arrive at very interesting conclusions.

Isotopes are versions of atomic elements with different numbers of neutrons. For example, carbon-12 contains six protons and six neutrons, while carbon-13 contains six protons and seven neutrons. Meanwhile nitrogen-14 has seven protons and neutrons each, while nitrogen-15 has seven protons and eight neutrons.

These isotopes can form through subtly different processes, at different times and in different locations in the galaxy. The ratio of these isotopes in the gases released by comet 3I/ATLAS into its coma and tail as it neared the sun and grew warmer can therefore tell us much about its origin and history.

Consequently, interstellar objects such as 3I/ATLAS "are sort of fossils from a planetary formation process that happened very far away, but we get the chance to study from much closer," said astronomer Cyrielle Opitom of the University of Edinburgh in a statement.

Opitom led the team who got the chance to observe 3I/ATLAS with the VLT. They found that the ratio of carbon-12 to carbon-13 is higher than is found in comets in our solar system or indeed in the local interstellar medium. Carbon-13 is produced in greater abundances than carbon-12 over time, typically in red giant stars, so for there to be far more carbon-12 than carbon-13 tells us that 3I/ATLAS was born long ago before carbon-13 had a chance to build in abundance across the galaxy. This finding supports the JWST carbon isotope measurements.

Additionally Opitom's team, which was co-led by Jean Manfroid and Damien Hutsemékers of the University of Liège in Belgium, measured a ratio of nitrogen-14 to nitrogen-15 in 3I/ATLAS that is more than twice as large as the value measured in comets native to our solar system. In fact, the ratio is typical of that found on the outer edge of planet-forming discs around young stars, implying 3I/ATLAS formed a long way out from its parent star, perhaps in the equivalent of its Kuiper belt.

"Unlike comets from our solar system, this interstellar visitor carries unusually high carbon and nitrogen isotopic ratios," said team-member Aravind Krishnakumar, who is also of the University of Liège.

The results give us clues to how 3I/ATLAS found itself wandering the space lanes alone for billions of years. Models indicate that migrating giant planets can kick small bodies into interstellar space, but the location of 3I/ATLAS's birth far from that planetary action means that it is quite possible instead that it was snatched from its parent star by the gravity of a passing star and was subsequently hurled into deep space.

The JWST had also previously shown that 3I/ATLAS is rich in carbon monoxide and carbon dioxide relative to water, and also contains unexpectedly high abundances of nickel and iron and a very high abundance of methanol relative to hydrogen cyanide – all of which tells us that 3I/ATLAS formed in an environment with conditions and chemistry notably alien to our own solar system.

Unfortunately similar measurements were not possible with the other two known interstellar objects – 1I/'Oumuamua was not seen to outgas, while 2I/Borisov was too faint. However, 3I/ATLAS is a tantalizing indication that studies of more interstellar objects caught entering our solar system will be able to teach us about planet-forming conditions across both space and time in our Milky Way galaxy.

"3I/ATLAS is a really exciting opportunity to probe the composition of another planetary system, one that formed long before our Sun and solar system even existed," concluded Rosemary Dorsey, an astronomer from the University of Helsinki in Finland.

The findings were published on July 6 in the journal Nature Astronomy.

Three years before the skyscraper-size asteroid Apophis makes its very close (but safe) flyby of Earth, scientists have already begun charting exactly when and where billions of people can watch it sweep across the sky.

Speaking at an "Apophis T-3 Years" workshop held earlier this month at the University of Padua in Italy, retired cartographer Michael Zeiler and astronomer Rick Fienberg shared detailed visibility maps charting the asteroid's passage across Earth's skies.

According to their calculations, roughly 90% of the world's population — about 7.6 billion people — lives in regions where Apophis could, in principle, be seen with the naked eye on April 13, 2029. The actual viewing success will depend more on earthly considerations, however, including cloud cover and the extent of light pollution.

Known formally as 99942 Apophis, the space rock will not resemble a blazing meteor tearing through the sky. Instead, scientists say it will appear as a point-like speck of light gliding steadily across, which, at its closest approach, will appear to move by about the apparent width of the full moon every minute.

"It will definitely be noticeable," Fienberg told Space.com. "It's going to be moving more slowly than a satellite — it will cross the sky in hours, rather than minutes, and it will just be a point."

According to the new maps, the asteroid should remain visible to the naked eye for about seven hours, beginning over Australia at 11:00 a.m. EDT (15:00 UTC) and concluding over the North Atlantic at 6:00 p.m. EDT (22:00 UTC).

At 4:35 p.m. EDT (20:35 UTC), Apophis is expected to reach its greatest apparent brightness as it passes over Cameroon, offering prime viewing to an estimated 3.9 billion people across Africa, Asia, eastern South America and parts of Europe.

About an hour later, at 5:45 p.m. EDT (21:45 UTC), the asteroid will make its closest approach to Earth, passing about 19,700 miles (31,600 kilometers) above the North Atlantic — well inside the orbit of Earth's geostationary satellites. The event would be visible across much of South America, the United States, Africa and parts of Europe, reaching roughly 2 billion people.

"This is the first time we've been able to predict in human history an asteroid visibly passing by the Earth," Richard Binzel, a professor of planetary sciences at the Massachusetts Institute of Technology (MIT), said during the workshop. "That's part of a shared experience."

As excitement ramps up for the once-in-a-millennium spectacle, Binzel opened the workshop with three messages: "Apophis will safely pass the Earth. Apophis will safely pass the Earth. Apophis will safely pass the Earth."

That absolute certainty is the hard-won fruit of more than two decades of increasingly precise observations. When Apophis was discovered in 2004, early calculations suggested a 1-in-37 chance of an impact in 2029, making it the most potentially hazardous asteroid known at the time. Additional observations steadily refined the asteroid's orbit, eliminating any possibility of a collision in 2029 and also ruling out any impact threat for at least the next century, according to NASA.

With the impact threat removed, scientists now view the flyby as a rare opportunity to observe how Earth's gravity affects an asteroid during an exceptionally close encounter.

Our planet's gravity is expected to tug the asteroid into a new orbit around the sun without posing any future danger. During the flyby, however, those same gravitational forces may stretch and squeeze the asteroid enough to trigger landslides or expose pristine material hidden beneath its weathered surface. Or they may do almost nothing.

"We simply don't know what's going to happen," Binzel said during the workshop. "Apophis may go by and not care too much, or maybe we'll see something significant."

"That's why we have to look," he added. "We're gonna learn a lot either way."

At the workshop, scientists said they hope to monitor the flyby from observatories in Spain's Canary Islands, among other places, as its location in the Atlantic Ocean offers an ideal view of the asteroid's closest approach as well as favorable prospects for clear skies.

Humanity has likely dreamed of flight since the very beginning, marveling at birds soaring overhead and trying to puzzle out their seemingly magical secret.

We made some halting steps over the centuries — getting kites aloft in ancient China, for example, and drawing up ambitious but unrealized flying machines during the Renaissance — but our boots were still firmly rooted on the ground when the United States of America was born on July 4, 1776.

Things changed just a few years later, however. In November 1783, a hot-air balloon designed by the Montgolfier brothers carried two men on a 25-minute flight over Paris, beginning our species' exploration of the heavens.

Another 120 years passed before we managed to fly with a powered, heavier-than-air craft, a milestone notched by the Wright brothers in North Carolina on Dec. 17, 1903. Remarkably, it took us less than half that long to make the jump from the sky to the final frontier, which cosmonaut Yuri Gagarin did for the first time on April 12, 1961.

Eight years later, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin walked on the moon — a remarkable achievement that was the climactic moment of the Cold War space race between the United States and the Soviet Union.

Over the next three and a half years, five more Apollo missions landed on Earth's nearest neighbor, leaving behind flags, footprints and defunct machinery. Now, more than half a century later, our species is gearing up to go back — but this time, in a much different way.

NASA wants to build a base near the moon's south pole over the next decade or so, an ambitious project the agency is undertaking via its Artemis program. And this is not an end in itself; NASA believes the knowledge gained from establishing such an outpost will help humanity make the next giant leap — to Mars.

The ball is rolling on Artemis, with two successful missions already in the books. Artemis I launched an uncrewed Orion capsule to lunar orbit and back in late 2022, and Artemis II sent four astronauts on a loop around the moon this past April. Next up is Artemis III, which will test docking procedures with one or both of the Artemis program's lunar landers (SpaceX's Starship and Blue Origin's Blue Moon) in Earth orbit in 2027. If all goes well with that flight, Artemis IV will put astronauts down near the lunar south pole, possibly as soon as 2028. (That timeline is far from guaranteed, however, as much development work remains. For example, neither Starship nor Blue Moon has yet reached Earth orbit or been cleared to carry humans.)

This is all happening in the context of a new space race, this time with China. The nation plans to land astronauts on the moon by 2030 and has been ticking boxes that keep this timeline within reach. And China aims to build a base of its own — also near the moon's south pole, which is thought to be rich in water ice — in collaboration with Russia and other partners.

What does all of this mean for the United States? Well, the nation came of age industrially after the Wright brothers' historic flight and has been a leader in aerospace tech and exploration ever since. The U.S. can accomplish amazing things in the final frontier, especially when pushed by a rival, so the years just after its 250th birthday may be quite eventful indeed. Stay tuned!

On July 4, the United States of America celebrates its 250th birthday, marking the anniversary of the Declaration of Independence and becoming a sovereign nation.

Today, this relatively young country leads the way in our understanding of the universe. It's where many major players in space science, like NASA, the California Institute of Technology (Caltech), the Massachusetts Institute of Technology (MIT), and Northwestern University, to name just a few.

And to celebrate 250 years of the U.S. as an independent nation, Space.com takes you on a journey through some common misunderstandings of the universe through the years and the roles American scientists played in clearing up that cosmic confusion.

By 1776, Sir Isaac Newton's laws of motion had been around for about 89 years since the publication of Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) in 1687. Five of the solar system planets had been discovered by the Ancient Greeks long before the birth of the U.S. Also, after a long struggle and many attempts to stifle this knowledge, humans were made aware that the Earth orbits the sun rather than the other way around, with the final nail in this coffin of misunderstanding laid by Polish astronomer Nicolaus Copernicus in 1543 and Galileo Galilei in 1610, receiving an extra hammer blow from Newton in 1687.

Galileo had also delivered us to the understanding that not only was Earth's place in the solar system unique, but it wasn't even the only planet to possess moons, with the moons of Jupiter, Io, Europa, Ganymede and Callisto discovered in 1610.

Clearly, by the time the U.S. was born we were already beginning to understand the universe and our place within it, but some major misunderstandings still persisted. One of the largest of these surrounded the nature of the sun itself.

The sun as a burning lump of coal

America was formed during the "steam age," a period of industrialization that lasted from 1770 to 1914. This revolution was driven by coal, powering locomotives, ships, and factories, changing the shape of industry, transportation, and manufacturing. At this time, coal was the densest and most powerful fuel source known to humanity, so it is perhaps little wonder that many early scientists theorized the sun was actually a tremendously massive lump of burning coal.

Then, one of the oldest and most prominent scientific periodicals in the world, the U.S.-based Scientific American, wrote a 1863 article that first began the pushback against the sun as a burning lump of coal.

"If the sun were composed of coal, it would last at the present rate only 5,000 years. The sun, in all probability, is not a burning, but an incandescent, body. Its light is rather that of a glowing molten metal than that of a burning furnace. But it is impossible that the sun should constantly be giving out heat, without either losing heat or being supplied with new fuel," the Scientific American article stated. "Assuming that the heat of the sun has been kept up by meteoric bodies falling into it, it is possible from the mass of the solar system to determine approximately the period during which the sun has shone. The limits lie between 100 millions and 400 millions of years."

Though this estimate was still miles out, we now understand that the sun is around 4.6 billion years old; this development came at a time of a geological revolution that was uncovering evidence that our planet was much older than theological estimates of just a few thousand years.

Around 57 years later in 1920, British scientist Arthur Eddington first suggested stars like the sun are actually powered by the nuclear fusion of hydrogen to helium. The idea was published by Eddington in his 1926 book, "The Internal Constitution of the Stars." Twelve years after this, nuclear physicist Hans Bethe formulated the first explanation of this nuclear fusion process, detailing the proton-proton chain reaction and the Carbon-Nitrogen-Oxygen (CNO) cycle.

The idea of the sun as a burning lump of coal finally burnt out 162 years after the formation of the U.S., a chain reaction kick-started by an American publication.

Ether or…?

During the infancy of the U.S. in the 1800s, scientists understood that light is a wave. Applying this to what they knew of other waves, it was logical to presume that light also needed a medium through which it could propagate. This medium would have to be ubiquitous and possess some unique properties to allow light to propagate through it at the speed of light.

Thus, it was proposed that space was filled with a medium called the luminiferous ether, with luminiferous meaning "light-bearing." The fact that this would have to be an invisible and infinite material that doesn't interact with physical objects made the existence of the luminiferous ether highly controversial.

We now know this medium doesn't exist, and that is thanks to two American physicists, Albert A. Michelson and Edward W. Morley, who in 1887 delivered the most important null result in the history of science: disproving the existence of the luminiferous ether.

Should the luminiferous ether exist, then scientists reasoned that as the Earth orbits the sun at around 66,000 miles per hour (106,216 kilometers per hour), our planet should be moving through the ether, which had been deemed to be stationary. That meant Earth must be moving with respect to the stationary ether. And if the ether is the medium through which light waves ripple, this should mean the speed of light differs ever so slightly in the direction Earth is traveling.

Conducted in Cleveland, Ohio, the Michelson–Morley experiment used a piece of kit called a Michelson–Morley interferometer to test differences in speed for a wave of light traveling perpendicular to Earth and one traveling parallel to Earth. Michelson and Morley had expected to observe an interference pattern caused by the differing travel times of the light waves.

That is what happens when light of the same wavelength arrives at a detector at ever so slightly different times, meaning the peaks and troughs of the waves no longer perfectly align. However, to the surprise of the American physicists, no interference was detected. This meant no difference in the travel speed of light, essentially disproving the existence of the ether.

The negation of the luminiferous ether was of vital importance as it opened the door to Albert Einstein's theory of special relativity in 1905 and general relativity in 1915, the latter of which revised our understanding of gravity and led to our knowledge of black holes and gravitational waves well before the experimental observation of such objects.

Other galaxies!

Though scientists realized Earth isn't in the center of the solar system before the birth of the U.S., there was another glaring misconception. It was believed that the Milky Way, first proposed in Immanuel Kant's "Island Universe" theory in 1755, still occupied a unique position in the universe — with the existence of other galaxies a hotly debated topic. The solar system itself was also thought to be at the center of the Milky Way.

In 1785, astronomer William Herschel set about mapping our galaxy, correctly determining the disk-like shape of the Milky Way but incorrectly placing the solar system at its heart. This picture changed in 1918, when American astronomer Harlow Shapley determined that dense groups of stars called globular clusters are centered on a distant core in the direction of the Sagittarius constellation. This placed the solar system off-center in the galaxy. Today we've expanded upon this, moving our planetary system 27,000 light-years away from the Galactic Center and onto one of our galaxy's spiral arms.

It was five years later, in 1923, that the uniqueness of the Milky Way was shattered. Using the 100-inch (2.5-meter) Hooker telescope at the Mount Wilson Observatory, American astronomer Edwin Hubble imaged the Andromeda nebula (Messier 31) and determined that it was at least a million light-years away. Though we now know this distance is closer to 2.5 million light-years, it was still enough to place M31 outside the boundary of the Milky Way.

The fact that the Andromeda nebula is actually the Andromeda galaxy, a distant and separate galaxy from our own, was announced to the public via The New York Times in Nov. 1924. We were no longer alone galactically — but Hubble wasn't done.

The universe is not static

Another assumption at this time was that the universe was static, something supported by Einstein in 1917. However, in 1929, Hubble discovered that the light from distant galaxies was being redshifted. In other words, the wavelengths of light emanating from these sources were being stretched as those wavelengths traveled toward us. This indicated that these galaxies are moving away from us. Convinced of this, Einstein abandoned his model of the static universe.

American scientists weren't done revising our entire picture of the cosmos, however. In 1998, U.S. researchers like Saul Perlmutter, Adam Riess, and Robert Kirshner were part of two international teams of researchers that discovered that not only is the universe expanding, but this expansion is actually speeding up.

Dark energy was introduced as the mysterious force driving this accelerating expansion. It remains today one of the most pressing mysteries of the cosmos.

Possibly by the time the U.S. celebrates its 300th birthday, the mystery of dark matter will have been solved along with other cosmic puzzles such as the nature of dark matter. If this is the case, it is highly likely that U.S. projects like the Hubble Space Telescope, the James Webb Space Telescope, and the upcoming Nancy Grace Roman Space Telescope will put American innovators and scientists at the forefront of these developments, just as their predecessors have been for the last 250 years.

Astronomers have used the James Webb Space Telescope (JWST) to observe an oddball gas giant exoplanet orbiting a dead star, a white dwarf, located some 80 light-years away. This "life after death" system gives scientists a portentous vision of what the solar system may look like in around 6 billion years after the sun has exhausted the hydrogen in its core, shed its outer layers, and left behind a smoldering white dwarf stellar remnant.

Prior to the final stages of that transformation, our star will have become a red giant, swelling out to many times its original radius, swallowing the inner rocky planets including Earth but leaving the outer planets  — although changing them irrevocably. Reflecting this, the white dwarf at the heart of this research is orbited by a Jupiter-sized exoplanet, designated WD 1856 b.

As WD 1856 b orbits its dead parent star, it crosses or "transits" the face of this white dwarf, known as WD 1856+534. By observing these transits with the JWST, the team was able to measure the mass and temperature of this Jupiter-like planet while also observing the composition of its atmosphere. To their surprise, they found WD 1856 b is hotter than expected. They also discovered how this planet came to have such an unusually tight orbit around its host white dwarf star.

"We're used to looking back in time when we use telescopes, but this is the first time we have been able to look forward to what might happen to the outer planets around the remnant of a sun-like star; it's like using a time machine to peer into the distant future of our solar system," team leader Ryan MacDonald from the University of St Andrews in Scotland said in a statement. "This is just the beginning of our exploration of planets orbiting dead stars with Webb, and the search for further planets orbiting white dwarfs is ongoing.

"Our results show that stellar death is not the end  — some planets experience a vibrant and lively future after the death of their star."

The team's research was published on Wednesday (July) in the journal Nature.

Survivor planet is a real oddball

The gas giant WD 1856 b was first discovered in 2020 by NASA's exoplanet-hunting spacecraft TESS (Transiting Exoplanet Survey Satellite) and the Spitzer Space Telescope. TESS detects exoplanets using the tiny dips in starlight they cause as they transit their host stars, blocking starlight.

This was the first intact planet ever discovered closely orbiting a white dwarf. What immediately stood out about WD 1856 b was how close its orbit is to its white dwarf host. The orbit is around 2% the size of Earth's orbit around the sun and takes just 1.4 Earth days to complete.

"The planet is quite the oddball. It's about the size of Jupiter, but the white dwarf it orbits is the size of Earth, so the planet is seven times larger than its star," MacDonald said.

The planet couldn't have always been in such a close orbit to its star. If it had, it would have been obliterated when the star transformed into a red giant before shedding its puffy outer layers and leaving behind a white dwarf.

"The big question is how WD 1856 b ended up where it is today, and there are two theories," team member Christopher O'Connor of Northwestern University said. "One is that the planet was swallowed by the host star as it was dying, and managed to survive on the inside. The other is that the migration took place due to the gravitational effect of other objects in the system. The white dwarf is part of a triple star system, and the outer companion stars could have influenced WD 1856 b's orbit."

The clue that allowed the team to differentiate between these migration mechanisms was the temperature of WD 1856 b, which at 260 degrees Fahrenheit (127 degrees Celsius) is about 240 degrees hotter than it would be if its only source of heat were the light from its white dwarf parent star.

With no energy available to warm the planet to these temperatures, the team reasoned that the temperature must be a residual effect of prior warming either from being engulfed by the red giant or during an inward migration. Using observations of the planet's mass of between four and 11 times that of Jupiter, the team was able to model how it would have cooled over time.

MacDonald and colleagues determined that WD 1856 b was likely heated up around 3 billion to 5.5 billion years ago. Its host star has been a white dwarf for longer than that, which means the exoplanet was safe during the star's destructive red giant phase, and moved into its tight orbit afterwards.

"As the planet moved inwards, its interactions with the strong gravity of the white dwarf will have caused it to warm up considerably, and it has been cooling ever since," O'Connor said.

The results indicate that Jupiter could move closer to the sun after the violent drama of its red giant phase and the destruction of the inner solar system. The findings also demonstrate the incredible observing power of the JWST and how the $10 billion space telescope is still discovering things no other instrument can.

"White dwarfs like WD 1856 are exceptionally dim compared to the planet-hosting stars we normally observe with the JWST," team member Victoria Boehm of Cornell University said.

"To make things even harder, the planet's transit only lasts 8 minutes, so it's very much if you blink you miss it! Capturing enough light to see WD 1856's spectrum, while also doing so quickly enough to not miss the transit, is something only Webb can do."

After Americans declared independence on July 4, 1776, a waning gibbous moon rose in the night sky. To the people celebrating the birth of a new nation, it would have looked much the same as the moon we see today. But there was one subtle difference: 250 years ago, the moon was about 31 feet (9.4 meters) closer to Earth than it is now.

"The moon is currently drifting away from Earth at a rate of about 3.8 centimeters [1.5 inches] per year, which is coincidentally roughly the same speed at which human fingernails grow," says Seth McGowan, president of the Adirondack Sky Center & Observatory in Tupper Lake, New York.

That 31 feet may sound significant, but against the moon's average distance from Earth of 238,855 miles (384,400 km), it's effectively nothing. In fact, the moon's elliptical orbit causes its distance from Earth to vary by about 26,000 miles (43,000 km) every month as it moves between perigee, its closest point to Earth, and apogee, its farthest. "The tiny 31-foot shift over 250 years is entirely swallowed up by that massive monthly variance," says McGowan. But while the moon itself looked much as it does today, the world beneath it was very different.

How Americans used the moon in 1776

Colonial Americans depended on the moon in ways that are easy to forget in an age of electric light and digital clocks. Travelers planned journeys around how much moonlight would be available on a given night. Farmers and Indigenous peoples consulted lunar cycles to anticipate seasonal changes. Mariners tracked the moon's pull on the tides. Even military planners considered lunar illumination — during the Revolutionary War, a moonlit night could aid troop movement and navigation, but it could also expose an army's position to enemy forces. The moon helped people organize their activities in an era when daily life remained closely tied to the natural world.

One of the most popular publications of the colonial era was the almanac. Long before weather apps — or even standardized timekeeping — Americans turned to these annual guides for practical information about moon phases, moonrise and moonset times, eclipses, tides, and seasonal events. Publications such as Benjamin Franklin's "Poor Richard's Almanack" helped popularize the format decades before independence, while later titles, such as "The Old Farmer's Almanac," first published in 1792, continued the tradition.

What astronomers knew about the moon in 1776

By the time the Declaration of Independence was signed, astronomers already understood a surprising amount about Earth's nearest neighbor. More than 160 years earlier, Galileo's telescopic observations had revealed mountains, valleys, and craters on the lunar surface, overturning the ancient notion that heavenly bodies were perfect spheres. Isaac Newton's laws of motion and gravitation had since explained why the moon orbited Earth and why tides occurred.

While astronomers could predict eclipses and chart the moon's movements with impressive accuracy, they had never seen the moon's far side, had no idea how it formed, and couldn't say with confidence what it was made of. All of that would come centuries later — and there are still many lunar unknowns today.

How Apollo astronauts revealed the moon's slow escape

During the Apollo missions, we learned an extraordinary amount of new information about the moon, including the rate at which it's moving away from Earth. Apollo astronauts installed retroreflectors — special mirrors designed to bounce light directly back toward its source—on the lunar surface. Scientists then fired lasers at those reflectors to measure how long it takes the light to return, allowing them to calculate the Earth-moon distance with extraordinary precision. (Fun fact: We continue to use the retroreflectors today!) Those measurements revealed that the moon is receding from Earth at about 1.5 inches (3.8 cm) per year.

"The moon's gravity pulls on Earth's oceans, creating a tidal bulge," says McGowan. "Because Earth rotates faster than the moon orbits us, that ocean bulge pulls slightly ahead of the moon, acting like a cosmic gravitational leash that accelerates the moon into a higher, wider orbit. In doing so, the Earth's rotation slows ever so slightly — about 2.3 milliseconds per century. "Back in 1776, a day on Earth was about 5.75 milliseconds shorter than it is now," says McGowan.

This effect is imperceptible on human timescales, but over millions of years, it will have dramatic consequences. Eventually, the moon will appear too small in Earth's sky to completely cover the sun, ending the era of total solar eclipses and leaving only annular, or "ring of fire," eclipses in their place. The moon will never completely free itself from Earth, though — physics dictates that the drift will stop after about 15 billion years. And well before that, in about 5 billion years, the sun will expand into a red giant, consuming both the Earth and the moon entirely.

Jared Isaacman is doing his best to spur his country on to sporting glory.

The NASA chief announced on Tuesday (June 30) that the agency will send a FIFA World Cup 2026 soccer ball to the moon if the U.S. men's national team manages to win the tournament, which is going on right now.

"So, a little bit of motivation for the United States here on this one," Isaacman said during a livestreamed press event on Tuesday. "We're going to one-up Alan Shepard in the golf game on the lunar surface, and we're going to get the soccer ball there."

Shepard famously smuggled two golf balls and an improvised club onto the Apollo 14 mission, which he commanded. On Feb. 6, 1971, the NASA astronaut hit those balls on the moon, becoming the first person ever to play a sport on another world.

The soccer-ball plan, by contrast, would be a sanctioned affair; Isaacman and Carlos García-Galán, manager of NASA's Moon Base program, are both behind it.

"I don't know which lander it'll wind up going in," Isaacman said during Tuesday's event, the second of the agency's monthly updates about its plans to build a crewed outpost near the lunar south pole via its Artemis program.

Turning to García-Galán, he added, "I'll leave that to you guys, to handle the payload."

"We will take on that challenge," García-Galán replied. "It will be super exciting to do that if they win. Good luck."

The U.S. men's team will probably need some luck to win the World Cup, an every-four-year event that's currently being jointly hosted by the U.S., Canada and Mexico. The American men have won just two knockout-round games in the entire history of the tournament, and one of those came in 1930, during the first-ever World Cup.

The 2026 team has performed better than most of its predecessors to this point, however; the Americans won their four-team group to advance to the single-elimination stage, beating both Paraguay and Australia before losing a meaningless game to Turkiye. (The U.S. had already clinched the group win at that point.)

The U.S. plays Bosnia-Herzegovina in a Round of 32 match on Wednesday (July 1). To hoist the World Cup trophy, the Americans would have to win that game, then four more after that, likely against some perennial soccer powers.

If they make it to the quarterfinals, for example, they'll likely face Spain, which won the World Cup in 2010 — a potential matchup flagged by García-Galán, who's from Málaga.

The U.S. women's soccer team has enjoyed a great deal more success at the international level, winning four of the nine FIFA Women's World Cups to date. (The women's tournament, which is also held every four years, was first played in 1991.)

A moon mission wouldn't be the first trip off Earth for the official FIFA World Cup 2026 soccer ball. NASA also sent one of the balls to the International Space Station, where astronauts played with it in the Kibo module.

"We're working to inspire the next generation by showing how space exploration inspires innovation in sports science — and everyday life," the agency said via X on June 20, in a post that included video of the off-Earth action.

Wildfires across the globe can be seen all the way from space. And one unexpected tool has come in handy to spot plumes of wildfire smoke: a satellite designed to study Earth's oceans.

What is it?

In this photo, we can see swirls of wildfire smoke over the Great Lakes in Canada. Fluffy white clouds float over the land and lakes, in contrast to the wisps of gray smoke, which float out from massive wildfires that ripped through North America.

The photo was snapped in May of last year by NASA's PACE (Plankton, Aerosol, Cloud, and ocean Ecosystem) satellite. This seems logical, as it is an Earth-monitoring satellite, but what's surprising is that the orbiting spacecraft was actually designed to study and monitor Earth's oceans and atmosphere. In fact, the image itself was captured by PACE's Ocean Color Instrument, which does "hyperspectral" imaging, meaning that it observes the planet in hundreds of different wavelengths of light (in visible, near-infrared and ultraviolet).

Why is it incredible?

This image, among others, shows the incredible versatility of space technologies like PACE. While wildfire monitoring isn't its explicit purpose, images and data from this mission could be incredibly helpful in deepening our understanding of wildfires and how they spread.

"The PACE satellite observes land too, and does it really well," Skye Caplan, terrestrial lead for the PACE mission at NASA's Goddard Space Flight Center in Maryland, said in a statement. "There is so much to explore with a new hyperspectral data set."

In fact, in addition to capturing wildfire smoke, as we can see in this image, PACE's Ocean Color Instrument can also spot changes in vegetation, burn scars and the charred aftermath of a wildfire. Images in the instrument's hundreds of wavelengths can reveal a variety of detailed information, such as how stressed, dry or even pigmented plants are on Earth's surface. This type of information could also be beneficial in identifying dry areas that could be at a higher risk of wildfires sparking.

Over the past 250 years, the number of "planets" in our solar system has ranged from six to nine — and, briefly, even 11 — depending on what astronomers knew at the time and how they defined a planet. As the United States prepares to celebrate its 250th anniversary, that changing tally offers a unique lens on humanity's evolving understanding of the cosmos since 1776.

Throughout history, astronomers have discovered new worlds, identified entirely new classes of celestial objects and repeatedly revised the very definition of a planet. The result is a surprisingly complicated answer to one of astronomy's most basic questions: How many planets are there in our solar system?

"The change in the number of recognized planets well represents how science is done," Kevin Schindler, historian and public information officer at Lowell Observatory, told Space.com. "Scientists discover something — a planet, dinosaur fossil, or beetle, for example — study it and classify it. With further study, and by studying more examples, scientists learn more and update their understanding of the thing, sometimes reclassifying it."

When the United States declared independence in 1776, astronomers recognized just six planets: Mercury, Venus, Earth, Mars, Jupiter and Saturn. That changed only five years later when William Herschel discovered Uranus in 1781, expanding the known solar system and increasing the planet count to seven.

The tally grew again in 1801 with the discovery of Ceres, a world orbiting between Mars and Jupiter. Three similar objects were found soon afterward, and for a time astronomers considered all of them planets, briefly bringing the total to 11. However, as additional objects were discovered, scientists realized they represented a distinct population and those objects were reclassified as asteroids, reducing the planet count down to seven, Schindler explained.

Neptune's discovery in 1846 raised the total to eight, while Clyde Tombaugh's discovery of Pluto at Lowell Observatory in 1930 established the familiar nine-planet solar system. This changing planet count underscores a broader pattern in humanity's journey of exploration and discovery over the past 250 years.

"I think it shows that exploration and the thirst to understand the universe around us is ingrained in us, it's part of our DNA and we continue to want to learn," Schindler said. "Our founding fathers established the United States based on scientific principles such as reason and logic, observation, evidence-based analysis, and openness to debate different points of view and be open to change."

For much of the 20th century, the answer seemed settled: The solar system had nine planets. However, beginning in the late 1950s, advancing spacecraft technology allowed scientists to study planets, moons and smaller bodies up close, revealing worlds far more diverse and dynamic than could be seen through telescopes alone. Then, in the early 1990s, astronomers began discovering a growing population of icy worlds beyond Neptune.

"The discovery of Trans-Neptunian Objects (TNOs) — numerous objects similar to Pluto but with orbits extending much farther away from the sun — tells us a lot about our 'local' environment," astronomer Kyler Kuehn, director of science, technology and operations at Lowell Observatory, told Space.com in an email, emphasizing the impact discovering TNOs has had on the classification of Pluto.

"While Pluto was the first TNO to be discovered, the fact that there could be millions of similar objects populating the outskirts of the solar system naturally leads to the question 'Why should we treat Pluto differently than any of the others?'" Kuehn said.

The growing number of TNO discoveries ultimately established that Pluto was part of the Kuiper Belt, a vast reservoir of icy bodies extending beyond Neptune's orbit. As a result, Pluto was no longer viewed as a unique outlier, but rather one member of a much larger population. This dramatically reshaped astronomers' understanding of the solar system, exposing a far more complex outer frontier than anyone in 1776 could have imagined.

"It doesn't fit into the relatively tidy structure of the solar system as understood in 1776," Schindler said. For 18th-century astronomers, "it likely wouldn't be a surprise to find new planets or a new class of planet-like bodies (asteroids), but the discovery of an entire new zone of bodies, which was more [chaotic], probably would have been a surprise, showing that the solar system is not nearly as tidy and stable as believed."

The debate surrounding Pluto's classification culminated in 2006, when the International Astronomical Union adopted a formal definition of a planet. Under that definition, a planet must orbit the sun, be massive enough to become nearly round under its own gravity and have "cleared the neighborhood" around its orbit. While Pluto met the first two requirements, it did not meet the third and was reclassified as a dwarf planet, dropping the official planet count from nine back down to eight.

Controversy over Pluto's classification continues today. Schindler said scientists who oppose Pluto's planethood typically favor a dynamical definition focused on how a body interacts with and dominates its orbital environment. Meanwhile, those who favor Pluto's return to planetary status generally support a geophysical definition based on an object's physical properties. In fact, Pluto's 2015 flyby by NASA's New Horizons spacecraft further fueled the debate by revealing a surprisingly complex world with mountains, glaciers and active geology.

"There has not been any resolution between the two sides," Schindler said, noting that public interest has also helped keep the debate alive.

Most recently, NASA Administrator Jared Isaacman added his voice to the conversation by saying he believes Pluto should once again be considered a planet and that the scientific community should revisit its classification.

"Arguing about the technical definition of 'planet' doesn't actually change anything about the (dwarf) planet itself, but how we classify things can be extremely important to the kinds of questions we even think to ask, " Kuehn added. "Scientific definitions have changed and will continue to change over the course of decades and centuries as we learn more."

The changing planet count demonstrates the foundations of how science works. Schindler compared Pluto's reclassification to the dinosaur Brontosaurus, which was renamed Apatosaurus after further study before later regaining its original classification as scientists refined their understanding.

Therefore, future discoveries, both within our solar system and beyond it, could further reshape scientists' understanding of planetary systems and how planets are classified.

"That might lead us to a more useful definition of planet than anything we are even considering now," Kuehn said. Looking forward, "I think we will learn a lot more about the extreme edges of our solar system — we have barely scratched the surface."

Two hundred and fifty years ago, astronomers knew of only six planets. Today, the official count in our solar system stands at eight, as the debate continues over whether that number tells the whole story.

As the United States marks its 250th anniversary, the changing planet count serves as a reminder that discovery is never finished. Every new observation has the potential to reshape our understanding of the cosmos — just as it has since America's founding — and perhaps even change the answer to one of astronomy's oldest questions: How many planets are there in our solar system?

NASA provided an Artemis update today (June 30), announcing new lunar landing contracts for its Moon Base initiative and a surprise new possible rover mission that could be headed to the moon's south pole.

During the second monthly update that NASA has provided for its moon base plans, the agency named Astrobotic, Firefly Aerospace and Intuitive Machines as the providers of four robotic landers that will deliver scientific payloads to the surface of the moon, as NASA tests and expands the technologies needed for a permanent human outpost.

"This is this drawing on the playbook that worked very well for NASA during the 1960s," NASA Administrator Jared Isaacman said during the livestreamed update, explaining the experiential approach to a crewed lunar return. "We didn't just jump right to Apollo 11."

Isaacman also announced the potential repurposing of an engineering development model built to mirror the agency's Perseverance and Curiosity rovers on Mars. "There is another," Isaacman said, quoting Yoda's line from "Star Wars: The Empire Strikes Back."

That test rover is called PROMISE, short for "Polar Rover for Observation, Mapping, and In-Situ Exploration" (though it was formerly known as Optimism). PROMISE was developed at NASA's Jet Propulsion Laboratory (JPL) in Southern California, where it has been used as a test platform for fixes or commands that engineers want to try on the ground before permanently sending them to Perseverance and Curiosity. Now, NASA wants to send PROMISE on a mission of its own.

Though sending PROMISE to the moon would leave Perseverance and Curiosity — both of which remain active on Mars — without an Earth-based testbed, Isaacman thinks it would be worth it.

"We've had years now of experience operating the two rovers on the surface of Mars, and we've got this hardware that the taxpayers have invested a lot in," he said. "So the question was posed: 'What if we send it to the moon?'"

With a little refurbishment, PROMISE would help advance NASA's lunar plans, Isaacman added. Like Perseverance and Curiosity, the test rover is powered by a radioisotope thermoelectric generator (RTG), which converts heat from naturally decaying radioactive material into electricity. So it wouldn't require sunlight to operate — a real benefit on the moon, where most locations experience long stretches of darkness. (NASA plans to build its Artemis base near the moon's south pole, which is thought to harbor an abundance of water ice and also has a relatively complex lighting environment.)

The other robots currently in the works to launch on future missions to the moon, including the landers announced during today's update, are all solar powered. Through 2029, NASA hopes to launch up to 20 such missions as part of the CLPS (Commercial Lunar Payload Services) initiative to support the first phase of the agency's moon base plans, and the landers announced today will be some of the first in that lineup.

Already expected this year was Blue Origin's Blue Moon Mark 1 cargo lander. It's slated to launch on the company's New Glenn rocket, which exploded last month during an engine test. That anomaly has complicated the Blue Moon timeline, though Blue Origin CEO Dave Limp has voiced confidence that New Glenn will launch again this year.

Two lunar deliveries were awarded to Astrobotic's Griffin 1 lander, one of which will fly Astrolab's FLIP rover the surface of the moon in the second half of 2026. Contracts to Firefly and Intuitive Machines call for the use of their Blue Ghost and Nova C landers, respectively, on CLPS missions in the next few years.

Each CLPS lander mission will carry at least three NASA payloads. The Stereo Camera for Lunar Plume Surface Studies (SCALPSS) array will study lander engine exhaust plume effects on lunar dust, to better predict landing requirements and prevent erosion and dangerous ejecta; a Laser Retroreflector Array (LRA) will test landers' ability to determine positioning and navigate using lasers and reflectors; and a Linear Energy Transfer Spectrometer (LETS) will measure radiation in the space around the moon and different areas on its surface.

"We know a lot about the moon, some of the south pole, but nothing like what we need to learn before we send humans there and we actually build a moon base," Carlos Garcia-Golan, NASA's Moon Base program manager, said during today's event. "So putting different assets on the surface, prospecting, understanding the environment and the places where we want to go [is] super critical."

Garcia-Golan is on board with the PROMISE moon plan as well. While it might sound crazy to send a spare Mars rover to the moon, it's the kind of crazy that NASA should be doing, he said. After all, JPL's motto is "Dare mighty things."

"We are in the business of the near impossible, so why not?" Garcia-Golan said.

Deep oceans of magma once sloshed about inside the crust of Mars, seismic measurements taken by NASA's InSight mission suggest.

The marsquakes detected by InSight show a boundary 15 miles (24 kilometers) deep between two different types of rock that were formed by enormous pools of magma. The presence of these magma pools could completely change what we thought we knew about the early development of Mars.

Already, scientists say the discovery could change what we know about the history of Mars. "One of the big questions in planetary science is whether Earth is unique," said the University of Oxford's Jon Wade in a statement. "If Mars could develop this kind of complex crust without plate tectonics, then maybe the conditions needed for habitability can emerge on more planets than we realized, including those previously dismissed based on size or their apparent lack of tectonic activity."

Earth is shaped by plate tectonics, the shifting of giant slabs of the planet's crust above our planet's molten mantle in a motion that generates earthquakes and volcanoes, but which also creates new land and regulates atmospheric carbon by drawing it out of the atmosphere and re-releasing it though volcanic eruptions. This constant reprocessing results in a fairly complex crust with multiple layers.

However, no convincing evidence has been found that the Red Planet has ever had plate tectonics. Instead, it is what we call a 'stagnant lid' planet, where the entire crust is one unbroken layer. Beneath this solid lid, all the way down to the mantle 23.6 miles (38 km) below the Martian surface, was considered to be fairly homogenous.

But NASA's InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission, which operated on Mars's surface between 2018 and 2022, put this to the test. InSight's seismometer was designed to detect tremors from marsquakes triggered by meteorite impacts or shifts in the planet's interior. These seismic tremors would reverberate through Mars, and InSight could learn about the interior structure of the Red Planet based on how they reached the lander.

Thanks to the way these tremors passed through Mars's interior after traveling at different velocities through different kinds of rock, InSight discovered a boundary between two layers of crust, but its existence has not been explained until now.

Researchers at the University of Oxford tasked themselves with figuring it out. Using geothermal models and statistics, the Oxford team identified the two types of rock that best matched the seismic data. They conclude that above 15 miles (24 km) deep is a thick layer of mafic rock, which is rich in iron, magnesium and silica. Below this depth is denser, crystalline ultramafic rock, which contains iron and magnesium but is depleted in silica and which descends a further 8.7 miles (14 kilometers) to the boundary between the crust and the mantle.

It seems as though the rock has become differentiated – the denser material having settled out below the lighter mafic rock. This could only have happened in huge pools of magma that once resided in giant pockets within Mars's crust. Like oil separating from water, the mafic and ultramafic rock separated over time, in a process called differentiation, before the magma cooled and froze the layers in place.

The pockets of magma could have extended for hundreds and possibly even thousands of kilometers around the planet, each pool linked to the others. Giant volcanic systems on Mars such as Olympus Mons and the Tharsis volcanoes would not have been isolated hotspots, but would have been interconnected beneath the surface.

This is something of a surprise – this kind of 'transcrustal magmatism' has only ever been found on Earth before. It's evidence that even though Mars lacked plate tectonics, it could still have undergone a degree of geochemical evolution and deep, complex geology.

This geology could even have supported a habitable environment by regurgitating carbon back into the atmosphere to maintain a greenhouse effect. Because of its small size and therefore low gravity and lack of magnetic field, Mars's atmosphere is notoriously leaky, and over its history, much of its atmosphere – including large quantities of its precious water – has escaped into space.

Large-scale volcanism, powered by interconnected chambers of magma, could have belched greenhouse gases back into the atmosphere, thickening the Martian atmosphere and maintaining warmer temperatures for longer.

But where did the magma come from? The Oxford team points the finger at upwelling from Mars' deep mantle, and with that magma came waves of heat that partially melted the crust, creating more magma. Both these processes took place on Earth during the Archaean Eon, which spanned between 4 and 2.5 billion years ago. On Earth, these processes contributed to the formation of the continents, although Mars' lack of plate tectonics and continents suggest that these processes were not as developed on the Red Planet.

Even so, some models suggest that mantle upwelling contributed to Mars' north–south dichotomy where the north contains mostly lowlands, which could have facilitated a large ocean, and the south is dominated by highlands.

"We've traditionally assumed that volcanism on Mars was relatively simple compared to that on Earth, but this discovery suggests that the planet could sustain massive, long-lived magmatic systems capable of evolving and reprocessing molten rock throughout the crust," said the study's lead author, Tobermory Mackay-Champion, who was previously at Oxford during the research but is now at the University of Bristol.

Mackay–Champion also highlights how this reprocessing of Mars's crust could have left metal deposits nearer the surface than had been thought.

"Mars may hold significantly more near-surface mineral wealth than previously recognized, boosting its potential for future mining, crewed missions and, eventually, permanent settlements," said Mackay-Champion.

While undoubtedly useful for a future outpost on Mars, this does raise the specter of companies pillaging and exploiting the Red Planet for its resources.

The findings were published on June 26 in Nature Astronomy.

BOULDER, Colorado — After Earth's moon and Mars, where could humans plant their footprints?

The "Humans to Titan Summit 2026" was held here on June 11 and June 12 to explore the concept of Titan, the largest moon of Saturn, as the next human exploration destination, post-Mars.

Researchers looked into how demanding such a trek could be and what would be required to make it, along with next steps to further that ambitious goal.

Normalizing the idea

As a first-of-its-kind gathering of experts, the Humans to Titan Summit 2026 was invigorating, taking seriously the prospect of one day sending humans to Titan, said Amanda Hendrix, director of the Planetary Science Institute, which is headquartered in Tucson, Arizona.

Hendrix is also president of the advocacy group Explore Titan and co-author of "Beyond Earth: Our Path to a New Home in the Planets" (Pantheon Books, 2016).

"Everyone recognizes that the reality of this is a long way off," Hendrix told Space.com, "but normalizing the idea   — that Titan is actually a very reasonable destination for humans  — is important."

Taking this goal seriously means that "we can have a next destination in our minds, after Mars," she added. "That keeps the momentum going."

Dense atmosphere

The assembly of experts explored an array of Titan topics, from spacesuits and modes of transportation, habitat designs and airlock concepts to light levels and possible encounters with monsoons and floods on the frigid, exotic moon, which has a weather system based on hydrocarbons rather than water.

Additionally, making use of Titan as a hub for launching sample-return missions to other moons within the Saturn system, like Enceladus, was viewed as a big plus.

So too was utilizing the moon's rich bounty of resources — like methane, nitrogen and oxygen — to fuel expansive, far-deeper exploration beyond Titan itself.

"We've got a lot of planning to do," said Hendrix, "but we have time!"

A top priority is figuring out how to either shorten the trip time to Titan or accommodate it and mitigate the negative effects on astronauts, Hendrix said.

"The top reason in my mind that Titan is such a good spot for humans is the dense atmosphere," Hendrix said. That nitrogen-dominated atmosphere provides natural shielding from harmful radiation of many types.

Precursor missions

Appreciation of what human visitors will face on the moon was boosted by the European Space Agency's robotic Huygens probe, which touched down on Titan on Jan. 14, 2005 as part of the NASA-ESA Cassini-Huygens mission to Saturn.

Next up for setting down on Titan is NASA's nuclear-powered Dragonfly, now projected to launch no earlier than 2028 for a six-year voyage to the faraway moon.

During its over three-year surface mission, Dragonfly's rotors will carry it for miles across Titan's surface, auto-piloting its way to a variety of areas. The vehicle is designed to snag samples of surface material for analysis inside the rotorcraft by scientific instruments.

Extraordinarily ambitious

Taking part in the two-day gathering was Scot Rafkin, director of the Department of Space Studies at the Southwest Research Institute (SwRI) and a planetary and atmospheric scientist. The summit was held at SwRI's Solar System Science & Exploration Division facilities.

"Everyone recognized that sending humans to Titan is extraordinarily ambitious. But history shows that the greatest achievements in exploration begin when people are willing to pursue goals that seem beyond reach," said Rafkin. Sharing with Space.com his own personal thoughts, he said the summit marked "the beginning of a long-term effort to imagine and ultimately achieve something transformative."

Titan is one of the most compelling worlds in the solar system, Rafkin said; it's a place with rivers, lakes, weather, dunes and complex chemistry unlike anywhere else we know of. Pursuing human exploration of Titan, he said, creates a long-term framework and provides a scientific purpose that transcends the moon and Mars.

'Not a question of physics'

Rafkin said that targeting Titan will also accelerate technologies needed not only for exploring that moon but for voyaging throughout the solar system.

"Human exploration of Titan is not a question of physics," said Rafkin. "It is a question of time, technology, and commitment. We understand most of the major challenges. We know many of the critical science and engineering gaps that remain."

Every advance in propulsion, power systems, manufacturing, robotics, computing, life support and communications, Rafkin said, brings Titan closer while simultaneously enabling exploration throughout the solar system.

Not every solution exists today, Rafkin continued, but the path forward is increasingly clear.

Starting a movement

"Some steps can be taken now, such as sending an orbiter to better characterize the Titan system," said Rafkin. "Other capabilities will require decades or even generations of development. The challenge is immense, but it is achievable."

Rafkin said that the summit was not about planning a mission.

"It was about starting a movement. If space exploration has taught us anything, it is that ambitious goals accelerate innovation in ways we cannot fully predict. The destination is Titan, but the investment is in ourselves," Rafkin concluded.

A second Humans to Titan Summit, said Hendrix, is slated around the launch date in 2028 of the NASA Dragonfly mission.

Update for 5:30 p.m. ET on June 30: During its Moon Base update today (June 30), NASA revealed a handful of new lunar-lander contracts and announced that it's considering launching a spare Mars rover to the moon. Read all about it here.

NASA will provide an update about its moon base plans this afternoon (June 30), and you can watch it live.

Agency chief Jared Isaacman and Carlos García-Galán, the manager for NASA's moon base program, "will discuss the next set of awards for new lunar lander missions and preview upcoming opportunities as the agency works toward building a sustained presence on the moon," NASA officials wrote in a media advisory.

The event will begin today at 2:30 p.m. EDT (1830 GMT). You can watch it live here at Space.com, courtesy of NASA, or directly via the agency.

The moon base is a core piece of NASA's Artemis program, which aims to establish a permanent, sustainable human presence on and around Earth's nearest neighbor over the next decade or so.

The Artemis architecture previously called for the assembly of a small space station in lunar orbit called Gateway. In late March, however, Isaacman announced that NASA was pausing its Gateway plans and instead focusing on building a surface outpost.

That base will be constructed near the lunar south pole, which is thought to harbor large amounts of water ice, a key resource that can be used for life support and also be split into hydrogen and oxygen to provide rocket fuel.

Construction of the base will require a variety of work by robotic lunar rovers and landers. Presumably, today's press conference will shine some more light on that work and reveal which companies will be contracted to do it.

NASA has launched two Artemis missions to date. Artemis 1 sent an uncrewed Orion capsule to lunar orbit and back in late 2022, and Artemis 2 launched four astronauts around the moon this past April.

NASA is currently gearing up for Artemis 3, a crewed mission that will test docking procedures between Orion and one or two privately developed lunar landers in Earth orbit.

The agency aims to launch Artemis 3 in mid-2027. If all goes well with that flight, Artemis 4 will land astronauts near the lunar south pole, potentially as early as late 2028.

Every year, millions of people travel to remote, protected "dark-sky parks" in search of experiences that depend on true darkness — photographing the Milky Way's heart arcing overhead, observing nocturnal wildlife in its natural rhythm, or simply standing beneath an ink-black sea of stars unblurred by artificial light.

Scientists have long warned that rising levels of artificial light — increasingly amplified by satellite megaconstellations orbiting our planet — are steadily eroding these nightscapes, disrupting ecosystems, affecting human health and dimming views of stars and distant celestial objects. Darkness itself carries no price tag, however, meaning its loss has largely been absent from the economic calculations that guide development and outdoor lighting decisions. Now, new research attempts to translate that loss visible in monetary terms.

A study combining satellite data with on-the-ground surveys of visitors at several "gold-tier" dark-sky sites found that people were less likely to choose parks with greater artificial skyglow or poorer night-sky conditions, and showed a clear willingness to pay more for darker skies.

On average, visitors would pay about $18 more per trip for marginally darker skies, and roughly $45 more per night for a one-step improvement on the Bortle Dark Sky Scale, a widely used measure of night-sky quality.

"This may seem really small at the per-visitor and per-trip unit estimate," said Jordan Smith, the study's lead author and director of the Institute of Outdoor Recreation and Tourism at Utah State University, "but when we scale through park-wide visitation, it becomes very, very significant."

Over a four-month period, the researchers estimated that light pollution reduced the recreational value of flagship dark-sky destinations in the U.S. by between $25 million and nearly $66 million.

The figures, presented at the 248th meeting of the American Astronomical Society in California, do not represent lost park revenue, but what economists call "welfare losses" — the decline in visitor satisfaction when environmental quality deteriorates. The concept is akin to paying for a concert expecting excellent sound and instead finding the speakers distorted; the performance still occurs, but it feels worth less than anticipated.

By assigning a dollar value to changes in night-sky quality, the researchers argue, policymakers gain a way to weigh the hidden costs of artificial lighting against the benefits of development and outdoor illumination.

"It's a foundational building block that allows that cost-benefit analysis to subsequently occur," Smith said.

Speaking at a press briefing during the conference, Smith said a central challenge is the gap between measuring light pollution and measuring what it costs in lived experience. Satellites and ground instruments can track where artificial light is spreading and how quickly it is increasing, he said, "but they can't tell us much about what that value is — what is actually lost due to anthropogenic light at night?"

To bridge that gap, Smith and his colleagues focused on the Colorado Plateau, a rugged region spanning Utah, Arizona, Colorado and New Mexico that contains one of the world's highest concentrations of "gold-tier" dark-sky sites, a designation that signifies the darkest and clearest night skies on Earth.

Over 82 nights in April, May, September and October, researchers interviewed visitors after dusk at campgrounds, scenic overlooks and parking areas. In total, they surveyed 634 travelers across nine destinations, including Arches, Bryce Canyon, Canyonlands and Natural Bridges National Monument, focusing on visitors whose trips depended specifically on high-quality night skies, the study notes.

By pairing survey responses with satellite measurements of nighttime brightness and local atmospheric conditions — including humidity, moonlight and airborne particles, all of which affect sky visibility — the team found a consistent preference for darker skies and a willingness to pay more for them.

The highest projected welfare losses, the researchers found, were heavily concentrated at premier destinations, led by the Grand Canyon and Zion national parks. Smaller or more remote parks showed comparatively modest total losses, a result driven by fewer visitors rather than an absence of dark-sky value, the study notes.

The researchers suggest that extending this kind of monitoring across a full year and over multiple years could help treat the night sky not only as a scientific and cultural asset, but as a measurable economic asset whose value changes with lighting policy, development and conservation.

As cities expand and artificial light continues to spread, studies like this are reframing a question once largely confined to science as an economic one: what is a star-filled sky worth?

Japan's Hayabusa2 sample-return spacecraft is on target to make one of the closest ever flybys of a near-Earth asteroid in early July, as part of its extended mission campaign.

Hayabusa2 launched in December 2014 and rendezvoused with the asteroid Ryugu four years later. The spacecraft collected samples and delivered them to Earth in 2020, completing its primary objectives. But the hardy spacecraft still has bold plans to deliver new and exciting science data.

The spacecraft has been operating well, despite needing to briefly enter a protective safe mode last year, and now is set to make a flyby of the asteroid Torifune on July 5, Satoshi Tanaka of the Japanese Aerospace Exploration Agency (JAXA) said in a presentation on Hayabusa2 during the 35th Meeting of the NASA Small Bodies Assessment Group (SBAG) on June 11.

The flyby will see Hayabusa2 get within 1 to 10 kilometers (0.62 to 6.2 miles) of Torifune, using its instrument suite to study the roughly 450-meter-wide (1,476 feet) asteroid as it whizzes past at 5.3 kilometers per second (3.3 miles per second).

"This is one of the closest asteroid encounters ever attempted by a mission of this class," Tanaka said. "By combining advanced navigation techniques and the engineering capabilities of Hayabusa2, we have made it possible to achieve a flyby at a distance of only about 1 kilometer."

Torifune was first given the designation 2001 CC21 before being named for a deity from Japanese mythology. Tanaka says the asteroid is somewhat similar to Itokawa — the target of Japan's first Hayabusa mission — but little is known for sure about Torifune, adding a level of uncertainty to this extended mission objective.

"It's still a risky operation, because they had not planned for this," Patrick Michel, the principal investigator for the European Space Agency's Hera asteroid mission and part of the Hayabusa2 science team, told Space.com. "The second thing is that we have a high uncertainty on the size of the object," he added, with the dimensions of the asteroid unknown.

The asteroid could, for example, be a contact binary, according to Michel, in which two separate bodies came together at low velocities. Known contact binary small bodies include the Kuiper belt object Arrokoth, imaged by NASA's New Horizons, and comet 67P/Churyumov-Gerasimenko, described as a "rubber duck" when visited by ESA's Rosetta spacecraft.

"We're going to discover what it looks like. And each time we have seen a new asteroid, we've been surprised," Michel said. "We're going to discover another beast to put in the zoo of asteroids."

The very high velocity of the flyby means there will be limited time to collect images and other data on the asteroid, but the rapid encounter will also provide a useful test for planetary defense, as well as adding to planetary science.

The flyby, using advanced navigation techniques to guide and control the spacecraft, will be a useful test of a rapid reconnaissance concept that could be used to determine the physical properties of an asteroid. Such reconnaissance could provide vital information before intercepting a threatening asteroid with a kinetic impact, as demonstrated by NASA's DART mission in 2022.

Tanaka said that Hayabusa2 has been busy during its deep space cruise phase, including making observations of the zodiacal light and exoplanets, and the Torifune flyby will, hopefully, not be its final act. The ultimate goal of the Hayabusa2 extended mission is to visit the tiny asteroid 1998 KY26 in 2031, which would be the smallest asteroid ever visited. The spacecraft could even attempt to land on the miniscule world, which is just 11 meters (36 feet) wide.

If you've ever seen auroras in the night sky, then you are one of the lucky few who has enjoyed a view of one of nature's most colorful and spectacular phenomena. But for the very lucky, very few who've seen auroras from space, the view is on a whole other level!

What is it?

When charged particles streaming constantly from the sun, also known as the solar wind, reach Earth and interact with our atmosphere, it creates what we call auroras. Seeing these spectacular, colorful displays in the sky is on many people's bucket list, as auroras can light up the sky in a rainbow of colors. But this beautiful phenomenon happening in our atmosphere can also be seen from space.

European Space Agency astronaut Sophie Adenot, who is currently aboard the International Space Station as part of the εpsilon mission, spotted the aurora australis, or auroras over the Southern Hemisphere. (Lights in the Northern Hemisphere are known as the aurora borealis.)

And the image she captured of the moment really speaks for itself. Neon green swirls look truly otherworldly against a haze of bright purple blanketing Earth, which also seems enveloped in a ruby red glow. The reddish glow of the auroras can even be seen against the outside of the space station in this photograph.

Why is it incredible?

While her photograph speaks for itself, Adenot actually shared her own thoughts on the view via social media. One incredible thing about human spaceflight in the modern world is that, even from an orbiting laboratory, astronauts can share their experiences with the world in real time.

"Day 127, orbit 1968 — That aurora was absolutely spectacular… shimmering and dancing beneath us, stretching as far as the eye could see, and so intense it lit up the Station in shades of green," Adenot said. "We’ve seen several since the beginning of the mission, but this one was on a completely different level — far too bright for my usual aurora camera settings. Moments like these never get old up here; the whole crew suddenly find themselves vying for a good spot at a window!"

Earth's moon is due for a human-made impact this August courtesy of a spent SpaceX Falcon 9 upper stage.

The Falcon 9 upper stage is left over from the launch that sent Firefly's Blue Ghost-1 lander to the moon on Jan. 15, 2025 by way of NASA's Commercial Lunar Payload Services (CLPS) initiative. Also sent moonward on that flight was the Hakuto-R Mission 2, called Resilience, a robotic lunar lander developed by the Japanese company ispace.

This striking event is expected to occur close to Einstein Crater near the moon's western limb and could be visible by ground and space-based telescopes. Varying forecasts have sparked debate on whether or not we'll be able to see the rocket body slam into the moon on Aug. 5, and, if so, how both citizen scientists and astronomers can best observe it it.

'This wonderful environment of the moon'

The consequences of this rocket mission's leftover hardware is on target for a "limb shot," meaning it could strike the far western edge of the moon. Another possible impact site is Bell Crater, just out of sight on the moon's far side.

Earlier this month, NASA's Solar System Exploration Research Virtual Institute (SSERVI) hosted a discussion with experts regarding the approaching impact. Taking part in the meeting of moon-watching specialists was Brian Day, SSERVI's lead for citizen science and community development.

"One of the things that is really important here with this impact that is coming up is it serves as a reminder to us that the moon is a dynamic environment. We think of it as being static. It is not. It is being whacked. It is changing," Day said.

Citizen scientists can actually get involved to help understand the dynamic environment of the moon thanks to the Impact Flash! program, said Day.

"And that can be done either with instrumentation you have in your own backyard or you can use ours in orbit around the moon," Day added. "This impact is a great reminder of this wonderful environment of the moon."

Moon viewing maybe

But will the impact be visible from Earth? Any assured answer is in a hedge-your-bet, yes/no mind bender.

"I've gone from 'probably' to 'probably not,' and more recently, to 'maybe,'" said Bill Gray of Project Pluto, creator of a telescope-tracking application used worldwide by professional and amateur astronomers alike to keep tabs on asteroids, comets, and other near-Earth objects.

It was Gray's work with Project Pluto that got the word out about the roughly four metric ton Falcon 9 upper stage intersection with the moon at over two kilometers a second. In September 2025, his software for computing orbits analyzed the observations and projected an impact with the moon on Aug. 5, 2026.

"Even though we have tracked it since launch, our idea of when and where it's going to hit are currently fuzzy by minutes and dozens of kilometers," Gray said. "But we will refine that and get an idea of where it's going to hit."

Out on a limb

"I think it's going to be very subtle. I think it's going to be very, very hard to see, if not impossible. But there's always a chance," said William Cooke, program manager of NASA's Meteoroid Environment Office at Marshall Space Flight Center in Huntsville, Alabama.

Cooke quickly added that, along with a rapid-fire impact flash, the upper stage impact will kick up huge amounts of lunar regolith, the dust that coats the surface of the moon.

"It will excavate that out of the crater and this may create a plume that will be illuminated by the sun," Cooke said. "So, it's not only important to look for the impact flash, but if this occurs close enough to the limb, you may be able to see that plume of material rising, and that would be significant as well."

Time and inclination

Still, concerning the spotting of that over-the-limb plume, it remains a guessing game.

How much material might be lofted, and how high will it go? Given the moon's one-sixth gravity, how long will it take for that material to fall back onto the lunar surface?

"So, no good feeling for how long the plume will be up there," Cooke said.

Putting aside all the unknowns, it is Cooke's view that "if you've got the time and the inclination, it might be worth a look."

Regarding the possibility of seeing the ejecta plume, Gray of Project Pluto, later told Space.com he agreed. "We pretty much shrugged about this and said "we dunno' and we should look and see if we can observe it."

On-location orbiters

Speaking of time and inclination, there is an on-location witness to the before and after results from the rocket stage plummeting into the moon.

Brent Garry is the project scientist for NASA's Lunar Reconnaissance Orbiter (LRO) at Goddard Space Flight Center in Greenbelt, Maryland. LRO will be passing over the projected crash site about seven days prior to the impact and about seven days after the impact, Garry said.

"After the impact we might have a little bit more knowledge of where it is. We can do some additional targeting about a week after the impact and get some targeting over where the site is," said Garry.

Different observers

This event emphasizes that when you're looking for impact flashes on the moon, either anthropogenic or natural, there's a need for as many observers as possible, said SSERVO's Day.

"Because these flashes are so short, they can very much mimic a cosmic ray impact on your detector and just be a sudden blip," said Day.

What really helps researcher's distinguish between cosmic ray impacts and actual flashes on the moon is to have different observers in different locations observing that flash at the same time, Day said.

"And if you see that, if you have that coincidence of events," Day said, "that's one of the reasons why we like to have as many people looking as possible."

Twice each year, we celebrate what we call a solstice when Earth is at its maximum tilt toward or away from the sun. And during this June's summer solstice, a European weather satellite managed to capture a striking image of the celestial moment from space.

What is it?

This image of the solstice was captured on June 21 by the European Space Agency's (ESA) Meteosat Third Generation (MTG) mission. This is a fleet of Earth-monitoring satellites that capture images of our home planet to support weather monitoring over Europe, Africa and regions of the Atlantic and Indian Oceans. The first Meteosat satellite launched in 1977 as ESA's first Earth-observing mission, and to date, there have been 11 satellites launched as part of this series.

In this image, the first of the third generation of Meteosat satellites, MTG-I1, captured an image of Earth just six minutes after we passed the moment of summer solstice, according to ESA. This image shows clearly Earth's "terminator line," or the fuzzy "line" that divides nighttime and daytime on a planet.

Why is it incredible?

On the day of a solstice when Earth is at its maximum tilt, there is almost exactly the same amount of daytime as there is nighttime. In the northern hemisphere, the June solstice marks the longest day of the year, or the day with the most sunlight. And, in the southern hemisphere, the June solstice marks the shortest day of the year.

In June, those in the northern hemisphere celebrate their extra hours of sunlight before the days start getting shorter again. Historically, solstices have been celebrated around the world, folded into cultural traditions and practices. As humans invented agriculture, and our food systems rely on things like available sunlight, it makes sense that throughout time, the changing duration of sunlight would be tightly intertwined with all aspects of our day-to-day lives.

If you stand outside the old Corn Exchange in Bristol, you'll see a clock with two minute hands above the entrance. One hand is set to London time, the other to Bristol's — ten minutes behind. The lag is because the sun reaches its peak over the second city a little bit after the first.

Of course, when it comes to scheduling anything with bounds beyond one city, having two poses an issue. This is why, in 1840, the British company Great Western Railway imposed what it called "Railway Time" across its whole network of trains, establishing Greenwich Mean Time as the first standardized time. And it's still the time zone used in the U.K. today. However, when several towns refused to adopt the time established by the Royal Observatory in Greenwich, the solution was to use two minute hands instead of one. And so the three-handed clock came to be.

That compromise could soon repeat itself in a less likely location: the moon.

The U.S. and China, the two largest space powers, disagree on what time it is on the moon. That's a problem because experts say satellites from one country will be unable to coordinate with spacecraft from the other during future space missions — which could risk accidents.

The White House has tasked NASA with establishing Coordinated Lunar Time (LTC) as a universal time on the moon, which would set the standard for NASA's LunaNet satellite system. But China has other ideas.

China's Chang'e Program, named after the Goddess who flew from the Earth to the moon in Chinese folklore, is the only space program with active lunar relay satellites, Queqiao-1 and Queqiao-2. These relay satellites are the first basis of a moon-wide GPS system meant for future space missions could rely on, meaning they compete with NASA's LunaNet — and because of the way GPS works, these satellites will need a standardized time situation. China is also the only space power to have landed spacecraft on the far side of the moon, where radio signals from Earth are blocked, proving it can coordinate landings without relying on commands from home.

In other words, while the U.S. surpasses China in terms of total space missions, the relay satellites could give China the edge when it comes to establishing the first lunar GPS system for future moon landings. China also hasn't agreed to use LTC for this system, raising the prospect that timekeeping standards could diverge.

Moon Race 2.0

Last year, experts warned U.S. Senators that China is set to win the moon race — the 21st century race to secure lunar resources establish a human presence on the moon — unless space operations receive more funding. Scientists further pointed out funding issues that could impact U.S. leadership in the lunar arena and wavering political commitment to Gateway, the space station intended to serve the Artemis moon program.

Private space-faring companies are also looking to governments to set international standards before spending money on expensive equipment. If China sets the standards before the US, private companies might gear with investments for Chinese customers, giving the country the edge over competitors.

"If everybody has their own standards, the complication increases for the user and manufacturers," says Bijunath Patla, a theoretical physicist at the National Institute of Standards and Technology (NIST). "So there is a chance of making some mistakes, errors, and interchanging, and then having a mishap."

GPS works by having satellites broadcast time signals. If the clocks on the satellites disagree, even by a microsecond, the GPS positioning can shift by hundreds of meters. In an emergency landing, that difference could prove expensive, or even fatal in the case of a human spaceflight mission.

If you take out the cellphone in your pocket, or look at the right-hand corner of your laptop to check the time, the precise time has been coordinated by hundreds of atomic clocks.

Atomic clocks created by NIST measure the oscillation of microwaves, the upwards and downwards swings of energy. Cesium atoms in the clocks absorb microwave energy only when oscillations reach 9,192,631,770 cycles per second.

Because all cesium atoms are the same, every atomic clock measures the exact same second as every other atomic clock. Their invention led to the universal standard of time we use today, superseding the time set by the Royal Greenwich Observatory in the 1800s.

International Atomic Time developed from the atomic clock, set by NIST’s optical "lattice clocks" and "cesium fountain clocks”, with the recently invented “nuclear clock” set to make the standard even more precise by ticking according to the fluctuations of thorium-229 nuclei.

The time on our screens comes from over 80 countries working with their own atomic clocks to work out the time. The U.S. Naval Observatory is one of these, submitting the time of its atomic clocks in Washington D.C. and Colorado to an international timekeeping organization in France.

Based in a suburb of Paris, the International Bureau of Weights and Measures (BIPM) collects the time from dozens of scientific labs across the world and uses the input from their atomic clocks to produce the weighted average time, what we call Coordinated Universal Time (UTC).

BIPM sends back corrections to each country, which recalibrate their own clocks to UTC. Countries beam these corrections to their satellites, which then transmit the standardised time to cell towers. The result appears on our phones.

But while our timekeeping methods are universal, time itself is not.

Spacetime

If the international atomic standard had been running since the Big Bang, NIST claims, it would not have gained or lost a single second since the universe began.

The way we experience time depends on gravity. The gravity we feel on Earth is determined by the mass and radius of our planet. Away from the Earth's gravity, spacetime behaves differently.

If one identical twin stayed on Earth, but the other travelled to a black hole, where matter is compressed, then both would experience time differently. Should the twin in the black hole take an atomic clock, and somehow survive, they would return to Earth to find that their twin had died, along with everyone they knew. Hundreds of millions of years would have passed by, according to the clock that remained on Earth, whereas their atomic clock would have ticked away only a short time.

"That person's time is being slowed down by gravity, their time is ticking slower," says Patla. "It's the same thing with the Earth and the moon. The clocks really tick faster."

Because of the physics of spacetime, coordinating missions with satellites away from the Earth's gravity gets increasingly difficult.

On the moon, clocks run around 56 microseconds faster than clocks on Earth. While everyone agrees on the math, not everyone agrees on who should wind the clock.

Because of the difference, space powers need to agree to convert the discrepancy into UTC, or an equivalent that works on satellites coordinating space missions. Without agreement, engineering equipment that relies on GPS could diverge, and missions could prove dangerous in the years ahead, particularly with the projected increase in space landings.

Aiming to land a crew on the moon by 2030, the Chinese space agency plans to establish a moon base by 2035, from which asteroid mining operations or future missions to Mars could be prepared. Atomic clocks on Mars tick about 477 microseconds faster per day, leading to suggestions of a Mars time zone. But Patla says a separate time zone for Mars may prove too complicated.

About time

Almost all space powers are targeting the south pole of the moon, where loads of frozen water presumably found there can be converted to hydrogen to use as rocket fuel for future space missions. Exiting the moon is less fuel-consuming than exiting the Earth's atmosphere, though assembling rockets on the moon has never been attempted.

But the south pole of the moon is scarred by impact craters and jagged mountains, which could make landing there more risky. In a historic moment, India was the first nation to land a spacecraft there in 2023 — and hundreds of launches from various countries are scheduled over the coming decades to achieve the same feat. As these launch attempts start to happen, converting between differing satellite times in an emergency could prove dangerous.

Luckily, there's more collaboration between the agencies than some might suspect. NIST has check-ins with China's Purple Mountain Observatory, which according to Patla are purely advisory, so the two countries can better coordinate their activities in space.

China has announced its own mathematical framework for timekeeping, the Lunar Time Ephemeris (or LTE440), which could complement NASA’s Lunar Time, building towards a more robust conversion between the two countries. The math and physics are not in dispute, Patla adds, a fact that should give policymakers some comfort.

"Most of the world uses UTC, and so there is an incentive for everybody to take the best route to get there," says Patla. "If we want to have a lunar economy and if we want to have a sustained presence on the moon, then the standards would be helpful to link moon time to Earth time."