Atoms and molecules from Earth's atmosphere have been traveling across space to settle on the moon for billions of years, new research has found, explaining a lunar mystery that goes back to the Apollo missions.

Not only do the findings point to a way in which a historical record of Earth's atmosphere could be deposited on the moon, but they also imply a healthy abundance of elements that could be useful to humans should we ever set up a lunar base.

In samples of lunar regolith brought back from the moon by Apollo astronauts, scientists have found puzzling amounts of volatiles, which in this case are elements such as water, carbon dioxide, helium, argon and nitrogen that have low boiling or sublimation points. Some of these volatiles are brought to the moon from the sun via the solar wind, but the abundances of these volatiles, particularly nitrogen, cannot solely be explained by the solar wind.

So, in 2005, scientists at the University of Tokyo proposed that some of the volatiles have come from Earth, as particles leaking out from our planet's upper atmosphere when they receive a nudge from energetic particles riding the solar wind. However, the Tokyo scientists believed this could only have happened in the early days of Earth's history, before our planet had a chance to develop a strong global magnetic field that they thought would block particles from escaping.

However, a team at the University of Rochester now suggest that this assessment was wrong.

The Rochester team, led by graduate student Shubhonkar Paramanick and astronomy professor Eric Blackman, used computer simulations to model when these volatile particles could have reached the moon based on two different scenarios.

One scenario depicted the early Earth, when our planet's magnetic field was weak and the solar wind was much stronger, describing the period in Earth's history when the Tokyo team reckoned that our atmosphere was more susceptible to being lost to space. The other scenario represented the modern Earth environment, with a stronger planetary field and a weaker solar wind emanating from the older sun.

Somewhat unexpectedly, the Rochester team found that the modern Earth scenario was actually more adept at transporting Earth's atmospheric particles to the moon.

That's because the simulations showed that, rather than blocking the particles' escape route, the Earth's magnetic field provided a highway for the particles. Some of our planet's magnetic-field lines are long enough to reach all the way to the moon.

In 2024, researchers at the University of Oxford found evidence in 3.7-billion-year-old iron-rich rocks in Greenland that the ancient Earth had a magnetic field comparable in strength to today. This is the oldest evidence we have of Earth's magnetic field, so from at least that time, and possibly earlier, through to today Earth's atmosphere has been leaking bit by bit into space and onto the moon.

"By combining data from particles preserved in lunar soil with computational modeling of how the solar wind interacts with Earth's atmosphere, we can trace the history of Earth's atmosphere and its magnetic field," said Blackman in a statement.

This means that the lunar regolith could still hold a very long-term record of Earth's atmospheric history, which in turn could teach us about how Earth's climate, environment and even life has changed over billions of years. Furthermore, the insights gained don't have to be confined to our planet.

"Our study may also have broader implications for understanding early atmospheric escape on planets like Mars, which lacks a global magnetic field today but had one similar to Earth in the past, along with a likely thicker atmosphere," said Paramanick. "By examining planetary evolution alongside atmospheric escape across different epochs, we can gain insight into how these processes shape planetary habitability."

Elsewhere in the solar system, Pluto's thin atmosphere also leaks onto its largest moon, Charon, although Pluto does not have an intrinsic magnetic field with which to transport its atmospheric particles. Instead, it is Charon's gravity that tugs at the particles in Pluto's atmosphere, with Pluto's weak gravity allowing the atmospheric particles to be stolen away.

This swapping of atmospheric atoms and molecules could also have positive repercussions for a future human presence on the moon. Water, for example, has obvious uses. (Water was also brought to the moon long ago by asteroid and comet impacts.) The fact that the stream of particles from Earth to the moon has been flowing for so long means that more volatiles than scientists expect might have built up on the lunar surface, just waiting for astronauts to extract them. In a way, it could be the ultimate down payment toward a human presence on the moon.

Then findings were published on Dec. 11 in the journal Communications Earth & Environment.

Prepare for a remarkable journey into magnificent magnification with "Nanocosmos: Journeys in Electron Space" (Abrams Books, 2025), a mesmerizing new science coffee table book from author, artist, documentarian and visual effects filmmaker Michael Benson. Here, size truly matters!

Inside this hypnotic 320-page hardcover, Benson takes readers into a strange miniaturized world exposed by the technological magic of scanning electron microscopes (SEM).

And here we have a pair of exclusive lunar impact glass images to share with you, taken from moon samples returned by the astronauts of NASA's Apollo 16 mission. Marvel at these diminutive gems brought home from outer space and wrap your mind around the micro-mini scale.

Per the book's official description, "The tiny worlds here, invisible to our unassisted eyes, are if anything more intricate, complex and extraordinary than anything so far seen in deep space. These include radiolarians, dinoflagellates and diatoms, as well as many varieties of insects, microscopic flowers and even lunar samples from the Apollo program. The composite mosaic micrographs in 'Nanocosmos' fuse art and science in revelatory ways, exposing an astonishing sublimity hidden to the naked eye."

Lunar impact glass is formed under the high heat and pressure caused by meteoroids hitting the moon’s regolith-covered surface. These impactors melt the disturbed lunar soil, creating molten material that instantly cools in flight to be manifested as glass shards, spherules and beads.

Benson produced "Nanocosmos" using hundreds of curated SEM scans that he captured over the course of six years at the Canadian Museum of Nature in Quebec. These sublime images display an uncanny beauty, symmetry, and design that defies all traditional descriptions.

In addition to art exhibits, films, and scientific endeavors into the mysteries of the universe, Benson was also responsible for supervising those swirling cosmology scenes in director Terrance Malick's "The Tree of Life" (2011) and "Voyage of Time" (2016). Additionally, he penned 2018's Hollywood history book titled "Space Odyssey" (2018), which chronicles the making of Stanley Kubrick's enigmatic sci-fi masterpiece from 1968, "2001: A Space Odyssey."

A mysterious lunar landslide might be the product of large chunks of debris from the impact that formed the crater Tycho slamming into the side of a moon mountain.

The Light Mantle, which is a bright 5-kilometer-long (3.1 miles) streak emanating from the base of a 2-km-tall (1.2 miles) mountain called South Massif, was a key target for NASA's Apollo 17 mission in 1972. With geologist Harrison Schmitt as a member of the crew, Apollo 17 returned from the moon with 243.6 pounds (110.5 kilograms) of rock samples, including two core samples from the Light Mantle.

There was so much material in the samples that some of it was kept away, stored and sealed, until the time came that scientists had better technology with which to study the samples.

That time is now.

"NASA were really forward-thinking during the Apollo missions to put some samples aside," said geologist Giulia Magnarini of London's Natural History Museum in a statement. "They were stored so that they could be studied using more advanced technology and new scientific approaches that hadn't even been thought of at the time."

The origin of the Light Mantle landslide is a mystery, partly because it is the only known landslide on the moon, meaning that we have nothing to compare it to. It's described as a "long run-out" landslide, as the debris that rolled down the mountain spilled out for a long way onto the Taurus-Littrow valley, but what carried it so far is also uncertain.

Using modern micro-CT scanning, which employed medical-level scans on the previously untouched core samples from the Light Mantle, Magnarini and her colleagues investigated clasts, which are rocky fragments that broke off from the slope of South Massif. They then compared the shape and composition of the clasts with what was predicted by computer models.

"The clasts tell us a lot about the process of the landslide itself and how the material within it has been transported," said Magnarini. "We saw that the finer material coating the clasts in the core comes from the clasts and not the surrounding debris, suggesting that the clasts broke up and helped the landslide to flow more like a fluid."

This would explain why the landslide produced such a long run-out, but what triggered the landslide in the first place? Magnarini's best bet is the formation 108 million years ago of the landmark lunar crater Tycho in the moon's southern hemisphere, far from Apollo 17's landing site.

Tycho is famous for its bright rays of ejecta material that cover a large area of the moon's southern hemisphere, and there are chains of small secondary craters leading away from Tycho, produced by large chunks of debris from the main impact falling back down onto the lunar surface. One of these chains points in the direction of South Massif and, despite the distance, Magnarini thinks that a chunk of debris from the Tycho-forming impact flew halfway around the moon and crashed into South Massif.

"It has been suggested that some of the material thrown up by the creation of Tycho might have struck South massif," said Magnarini. "This could have triggered the landslide that ultimately formed the Light Mantle."

Tycho's young age fits the bill; an older landslide would have been eroded away by micrometeorites long ago. That might be why we no longer see other landslides on the moon; impacts like Tycho are very rare now, compared to 3.5-4 billion years ago when most of the moon's craters formed.

Overall, Magnarini sees her research as helping to bridge the Apollo missions with the current Artemis program and NASA's plans to return astronauts to the surface of the moon.

"We've learned so many lessons from these samples about how to preserve, store and open lunar material without damaging the contents," said Magnarini. "This is already feeding into plans for Artemis' science and helping to develop new instruments."

Magnarini's team's findings were published Aug. 2 in the Journal of Geophysical Research: Planets.

The moon and Earth may be more different than previously thought, challenging existing models for how the moon formed, a new study finds.

Earth originated about 4.5 billion years ago, and previous research suggested that the moon arose a short time after that. For the past three decades, the prevailing explanation for the moon's origin was that it resulted from the collision of two protoplanets, or embryonic worlds. One of those was the newborn Earth, and the other was a Mars-size rock nicknamed Theia, after the mother of the moon in Greek myth. "Once the dust settled, two bodies were left — Earth and the moon," new study co-author Zachary Sharp, a planetary scientist at the University of New Mexico in Albuquerque, told Space.com.

This "giant impact hypothesis" seemed to explain many details about Earth and the moon, such as the large size of the moon compared with Earth and the rates of rotation of the two bodies. However, in the past 20 or so years, evidence has emerged to challenge that hypothesis and suggest a multitude of alternatives.

Related: How the moon formed: 5 wild lunar theories

Computer models of the giant-impact scenario often say that 70% to 90% of the moon should be made of material from Theia. The problem is that most bodies in the solar system have unique chemical makeups, and so the Earth, Theia — and therefore the moon — should too. However, rock samples that the Apollo missions returned from the moon show that the natural satellite's composition is uncannily similar to Earth's, much more similar than such models would predict for versions of elements called isotopes. (Isotopes of an element each have different numbers of neutrons in their atomic nuclei.)

This extreme similarity in isotopes of elements such as oxygen has raised great challenges for the giant-impact scenario. One possibility is that the proto-Earth and Theia were nearly identical to start with when it came to oxygen isotopes, which seems unlikely. Another is that the proto-Earth and Theia's oxygen isotopes were fully mixed in the aftermath of the collision, perhaps due to an impact so violent that it vaporized a large portion of the early Earth, with the moon emerging from the resulting, doughnut-shaped mass called a synestia. But this and other scenarios may require unlikely impact conditions, scientists have said.

In the new study, researchers conducted new high-precision measurements of oxygen isotope levels in a range of lunar samples. The researchers expanded on previous work by focusing on a wide variety of types of moon rock.

The scientists found that there were subtle but regular differences in oxygen isotopic composition depending on the kind of lunar rock tested, Sharp said. This suggested that prior work that averaged together lunar isotope data while ignoring differences in rock type might not have given an accurate picture of the differences between Earth and the moon.

"Going into this project, it was expected that our results would likely mirror that of previous studies," study lead author Erick Cano, a stable-isotope geochemist at the University of New Mexico, told Space.com. "The most surprising part of our results was finding the amount of variation that we did between the individual lunar samples."

Related: How the moon was made: Lunar evolution explained (infographic)

To explain these findings, the researchers suggested that the giant collision between proto-Earth and Theia did indeed lead to mixing between the bodies. Still, the resulting moon and Earth had distinct compositions, albeit very similar ones, Sharp said.

Later, in the first 1,000 or so years after the impact, vaporized rock from the disk of debris left behind by the impact likely led "to lava raining down on the moon for hundreds of years," Sharp said. Complex physical and chemical interactions between this lava rain and the ocean of magma that covered the newborn moon could then have led to an oxygen isotopic composition in the uppermost lunar rocks that was more similar to Earth's. In contrast, samples that came from the deep lunar mantle had the most different oxygen isotopic composition of the lunar rocks tested when compared to Earth.

The most important implication from these findings is that giant-impact models no longer have to account for virtually indistinguishable oxygen isotopic compositions between Earth and the moon, Cano said. "I think this will open the door for an entirely new range of impact scenarios," he added.

Future research can expand on this new study by analyzing other lunar samples, Cano said. "The obstacles for this future research may be the limited quantities of material that we have from the Apollo missions," he said. "Some of these lunar rock types were only brought back in very small quantities and can be very difficult to obtain for study."

Cano, Sharp and study co-author Chip Shearer, a lunar scientist also based at the University of New Mexico, detailed their findings online Monday (March 9) in the journal Nature Geoscience.

• What is the moon made of?
• How was the moon formed?
• The moon on Earth: Where are NASA's Apollo lunar rocks now?

Follow Charles Q. Choi on Twitter @cqchoi. Follow us on Twitter @Spacedotcom and on Facebook.

Between 1969 and 1972, Apollo astronauts brought back to Earth a total of nine containers of moon material that were sealed on the lunar surface. 

Two of the larger sealed samples were collected by Apollo 17 moonwalkers in December 1972. Three sealed samples from Apollo 15, 16 and 17 remain unopened. 

According to several key lunar researchers, now is the right time to consider opening at least one of the still-sealed sample containers. [NASA's 17 Apollo Moon Missions in Pictures]

Protected, preserved and processed

Home for the Apollo geological samples — specimens that are physically protected, environmentally preserved and scientifically processed — is the Lunar Sample Laboratory Facility, a special building at NASA 's Johnson Space Center (JSC) in Houston. 

The Apollo collection consists of lunar rocks, core samples, pebbles, sand and dust from the lunar surface. Thanks to the six Apollo landing expeditions, 2,200 separate samples made it back to Earth, snagged from six different exploration sites on the moon. 

Returned lunar samples have shown that they are the gifts that keep on giving. For instance, water from the moon's interior was detected recently by sensitive mass spectrometric analysis of basaltic glasses brought back to Earth by the Apollo 15 and Apollo 17 missions.

Careful planning

"Samples were intentionally saved for a time when technology and instrumentation had advanced to the point that we could maximize the scientific return on these unique samples," said NASA's Ryan Zeigler, Apollo sample curator and manager of the Astromaterials Acquisition and Curation Office in Houston.

But such investigations require careful planning and execution by a consortium of experts with experience in handling and analyzing lunar samples, Zeigler told Space.com.

"Given the recent renewed interest in the moon, and specifically about the volatile budget of lunar regolith, these sealed samples likely contain information that would be important in the design of future lunar missions," Zeigler said. 

"Volatiles" are substances with relatively low boiling points — materials such as water, hydrogen and methane. Understanding lunar volatiles could improve the productivity and value of future human involvement with the moon, scientists have stressed.

New insights

Zeigler isn't the only researcher who'd like to unseal some of the remaining Apollo samples. He's joined in this advocacy by Charles Shearer of the Institute of Meteoritics, Department of Earth and Planetary Science at the University of New Mexico and Clive Neal at the Department of Civil & Environmental Engineering & Earth Sciences at the University of Notre Dame in Indiana. 

They'll be making their case later this month at the 49th Lunar and Planetary Science Conference, which is organized by the Lunar & Planetary Institute in Houston, an arm of the Universities Space Research Association. The conference will be held in The Woodlands, Texas, from March 19 through March 23.

"Given the new emphasis on the lunar volatile story, having these unopened samples will, apart from yielding new lunar science insights, allow us to plan the sampling, return and analysis of volatile-bearing lunar samples," Neal told Space.com. "Hence a consortium approach in analyzing these and similar samples is the only way to go."

Pristine and unstudied

Apollo's set of unopened samples contain pristine and unstudied lunar material. Moreover, given that the total sample mass within the unopened containers of moon specimens exceeds projected masses returned by future robotic missions, each of the unopened samples should be treated as an individual lunar mission, the lunar experts contend.

For example, the researchers point to "unopened treasures" in the Apollo 17 sample collection. 

The Apollo 17 mission in December 1972 was a "J-style" mission. That means it was capable of a longer stay time on the moon and greater surface mobility via a wheeled vehicle. The expeditionary crew of Harrison "Jack" Schmitt and Eugene Cernan chalked up a total distance of 23 miles (36.9 kilometers).

Thanks to their moon rover, the lunar twosome gathered samples over a wide area in Taurus-Littrow Valley. The Apollo 17 mission returned 244 lbs. (110.5 kilograms) of a variety of sample types. This was approximately 30 percent of the total sample mass returned by the Apollo program, which collectively added up to 840 lbs. (381 kg). [Apollo 17: NASA's Last Apollo Moon Landing Mission in Pictures]

Seal status

But there's a bit of a catch. 

The unopened containers appear to be sealed based on their outward appearance. However, it's doubtful that the containers still retain the level of vacuum that exists on the moon. It is expected that the containers retain a more modest vacuum and that the samples have not come in contact with the terrestrial atmosphere. 

The bottom line is, nobody knows for sure the status of the seals until the containers are opened.

On one hand, the containers used during the Apollo program were a reasonable attempt to preserve many characteristics of the lunar regolith. But more important, these types of sample-containment concepts not only are expected to be used during future human missions to the moon, but may be applicable to robotic missions to the moon and other planetary bodies. 

Zeigler and his associates suggest it would be prudent to assume that analytical techniques will continue to improve in the future and science goals will change with additional observations and data. 

"Therefore, we are advocating opening a single sample container and saving the remaining two samples for future generations of lunar scientists," Shearer, Neal and Zeigler wrote in a paper they plan to present at the upcoming conference. 

On a personal note

A lot of serious thought over the past decade has gone into why and how to study the unopened lunar samples, said Carlton Allen, former astromaterials curator at JSC. He, too, is a supporter of opening one of the Apollo sample collections now, giving the following reasons:

Technology: Techniques are available to examine sealed samples before opening and to open them with minimal terrestrial contamination. 

Microanalysis: We can analyze trace gases and volatiles with the precision and accuracy needed to address fundamental questions in lunar science, such as the trace water in pyroclastic glass returned from the moon.

Lunar science: We understand many of the remaining gaps in lunar knowledge prior to a new era of exploration, and the precision/accuracy needed to address these gaps, such as existence and history of near-surface water and ice at a range of locations and temperatures.

Finally, Allen said there's a personal note, too. 

"Some of the astronauts who collected these samples, technicians who opened and documented core tubes and scientists who studied samples all the way back to Apollo are still with us and professionally active," Allen said. "We should not overlook these irreplaceable human resources." 

Editor's note: This story was updated March 6 to correct the name of Ryan Zeigler, NASA's Apollo sample curator and manager of the Astromaterials Acquisition and Curation Office in Houston.

Leonard David is author of "Mars: Our Future on the Red Planet," published by National Geographic. The book is a companion to the National Geographic Channel series "Mars." A longtime writer for Space.com, David has been reporting on the space industry for more than five decades. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.

Recentstudies have found vast amounts of water ice at or near the lunar surface. But theinside of the moon is bone dry, a new study finds.

A recentstudy of lunar rock samples from NASA's Apollo missions could mean the moon'sinterior harbors less water than thought. In fact, a new examination of thelunar rocks' chlorine composition indicates that the moon is essentially dry ?without any water deep inside at all.

"Lotsof publications about water being found on the moon talk about ice that resides on the lunar surface," Zachary Sharp, a professor at the Universityof New Mexico in Albuquerque, N.M., and the study's lead researcher, toldSPACE.com. "This is not what we're talking about. We're talking aboutwater that was initially in the moon as it formed."

Secretsof moon rocks

Sharpand his colleagues compared the composition of Earth rocks, primitive meteoritesamples, and lunar volcanic rocks. In particular, they measured the prevalenceof two kinds of chlorine atoms, called isotopes ? chlorine-35 and chlorine-37.

Theyfound that the ratio of chlorine-35 to chlorine-37 was very constant, and onlyvaried by about 0.1 percent. Similar results were found with the primitivemeteorite samples.

Butwhen the researchers performed the same measurements on lunar samples, theyfound surprising results. [10 Coolest New Moon Discoveries]

"Wequickly found huge variability in the lunar chlorine isotope ratio," Sharpsaid. "It was 25 times that of Earth. We were confounded."

Thisinformation helped the scientists calculate how widespread other elements areon the moon ? including hydrogen, a key ingredient in water. "Knowing thechlorine content, we can back-calculate the amount of hydrogen," Sharpsaid. "We found that the hydrogen content had to be really low, soessentially the moon was extremely dry relative to Earth."

Whatchlorine tells us about water

Becauseof its chemical properties, chlorine is very attracted to water (this is calledbeing hydrophilic). Therefore, it is an extremely sensitive indicator of thepresence of hydrogen, and thus, water.

Ifthe moon contained largeamounts of water in its interior, that would have greatly affected the propertiesof chlorine there, too, the researchers said. In particular, there wouldn't beso many different ratios of the two types of chlorine ? rather, they would befound at steady levels all over the moon, as they are on Earth.

OnEarth, chlorine bonds with hydrogen to create the compound hydrogen chloride(HCl), which is released as a gas during volcanic processes.Chlorine-35 andchlorine-37 are atoms that contain the same number of protons, but chlorine-37has two more neutrons in its nucleus. Thus, the latter flavor of chlorineweighs more, as it has a slightly greater atomic mass.

Duringvolcanic processes on Earth, as chlorine vaporizes from the cooling moltenrock, the volatile gas hydrogen chloride (HCl) is released. This compound ismore often made with chlorine-37 than chlorine-35. That means that when the gasis emitted into the atmosphere, more of the former atom is lost than thelatter, leaving behind cooled volcanic rocks that are enriched withchlorine-35.

But,this is only half of the process, Sharp said. The lighter element is alsoreleased as a vapor in other processes on Earth.

"Thenet effect on Earth is that there is essentially no fractionation ? the twocancel each other out," Sharp said.

However,on the moon, this cancelling out process hasn't occurred, so there are wildlydifferent ratios of the two isotopes in different areas. That must be becausethere wasn't enough hydrogen around for chlorine to bond to, to create HCl, thescientists reason.

Instead,on the moon, chlorine has bonded with metals to create compounds such as sodiumchloride, magnesium chloride and zinc chloride, Sharp said.

"Thelevels of hydrogen had to be less than the chlorine, otherwise we would haveHCl rather than these chloride salts," Sharp said. "If we had madeHCl, we wouldn't have fractionation. Knowing the chlorine content gives us anupper limit on the hydrogen content. So, we know that there had to be lesshydrogen than chlorine."

Withsuch low concentrations of hydrogen, the researchers suggest that the interior of the moon is anhydrous, or without water, as scientists had initially proposedlong ago.

Furthermore,if this explanation is correct, Sharp and his colleagues would also hope tofind salts on the lunar surface that were re-crystallized following the vaporizingprocess.

"Wedo see this on a number of lunar materials," Sharp said. "We findthese little decorations of salt crystals on the surface."

Previousstudies of water in the moon's interior

In2008, research of volcanic glass beads from the moon brought attention to the fact that there might be morewater in the lunar interior than scientists had previously thought.

But,Sharp claims that these samples are unusual, and might not be representative ofthe whole moon.

"Itwould be like if I asked you to bring back half a dozen rock samples from astreambed, and one of those samples glittered like gold," Sharp said."I could look at that and think that Earth contained a lot of gold, butit's really just an anomalous sample. It's a wonderful discovery, but to beable to extrapolate that to the entire moon may not be valid, and that couldexplain the discrepancy in that paper and ours."

Thenew discovery is detailed in the August 6 issue of the journal Science.

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