The volcano Ol Doinyo Lengai in Tanzania is unique on Earth: Its lava is rich in carbon compounds that melt at significantly lower temperatures than typical silicon-rich lavas from other terrestrial volcanoes.

It is possible, however, that carbon volcanoes could exist elsewhere, including on exoplanets, or—as suggested in a recently published article in Icarus—perhaps even on planet Mercury.

Despite being known from antiquity, Mercury is very hard to study because of its closeness to the Sun. As a result, the best data so far were gathered within the past 20 years by NASA’s MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) probe. In particular, scientists identified mysterious pits they dubbed “hollows” scattered across Mercury’s surface. The hollows’ relatively bright appearance indicates they were formed in recent geological times, and could even be still forming today. The origins and geochemical makeup of these hollows are unknown.

“Mercury looks like the Moon a little bit, so we don’t expect large volcanoes,” said Maximilian Paul Reitze, a planetologist at Universität Münster’s Institut für Planetologie who is first author of the Icarus study. Without volcanic conditions like those on Earth or even on Jupiter’s moon Io, researchers expect Mercury to be largely geologically dormant. In other words, to explain hollows, “we need some volcanism under the conditions we expect on Mercury,” Reitze said.

Hence the interest in Ol Doinyo Lengai, known as the Mountain of God to the Maasai and Sonjo peoples. This volcano produces lava made up of carbonatites, igneous rocks composed of more than half carbon (and which are known to host critical minerals). These lavas flow at temperatures roughly 100°C lower than Mercury’s blazingly hot daytime temperature of 424°C. If the planet has a carbon-rich subsurface, as Reitze and his collaborators proposed, then the hollows could be Mercury’s version of Ol Doinyo Lengai.

This theory, however, has its skeptics.

“We know that there is carbon in [Mercury’s] crust, but the amount is very low,” said Paul Byrne, a planetary scientist at Washington University in St. Louis, who was not involved in the Icarus study. He also pointed out that the surface regions where carbon is most concentrated don’t correspond to higher concentrations of hollows. “For this to be some kind of carbon-based lava, it would imply a lot more carbon than we might think, given how widespread the hollows are.”

The Making of a Weird Planet

Mercury’s proximity to the Sun means that NASA’s Mariner 10 spacecraft provided humanity’s first-ever views when it flew by in 1974 and 1975. Three decades later, the MESSENGER mission was the first probe to orbit Mercury, mapping the planet’s full surface and turning up unexpected features like the hollows. The BepiColombo mission, a joint project of the European Space Agency and the Japan Aerospace Exploration Agency, is only the third mission ever to visit the planet, so when its two spacecraft settle into orbit in November 2026, it will almost inevitably reveal something unexpected, because it’s a weird planet.

Unlike Earth, Mars, or the Moon, Mercury has a freakishly large core and a thin mantle.

“Basically, Mercury is a molten ball bearing wrapped in a thin blanket of rock,” Byrne said. “One explanation is that early in the planet’s life, either one large or several smaller impacts stripped the outer portion away.”

The question then becomes what got vaporized, and what was left behind, particularly when trying to understand hollows. Many planetary researchers proposed that sulfides in the mantle could drive volcanism, but Reitze had doubts.

“The problem with sulfides I see is that they’re stable up to 1,000°C or so, which cannot explain the explosive volcanism that’s needed to form those hollows,” he said.

Instead, he and his coauthors contacted a colleague working on Ol Doinyo Lengai, who obtained a sample of the lava for laboratory study while it was still molten. Because carbonatite lava reacts chemically with Earth’s air very quickly, the researchers needed to isolate it to understand how the unaltered materials might behave under conditions on Mercury, particularly infrared spectra that could be confirmed by the BepiColombo mission.

In the hypothesis proposed by Reitze and colleagues, impacts from meteorites heat the carbon-rich magma below Mercury’s surface, melting it and driving eruptions. The hollows, which are found frequently on the slopes of Mercury’s craters or their central peaks, are the remains of those eruptions. Over time, further meteorite bombardments and intense solar radiation destroyed older hollows, which is why the ones in MESSENGER data were all formed within the past 270 million years—a short time ago, geologically speaking.

“The carbonatite angle is an interesting one, and I certainly wouldn’t rule it out,” Byrne said. “Anytime people have been confident about anything in planetary science, [planets have] shown you wrong. I’m certainly open to it, but is it the only explanation for all of the hollows? I am skeptical of that.”

Byrne and Reitze both dream of a future Mercury lander, a very challenging and expensive proposition nobody expects will happen soon. In the meantime, they agreed that BepiColombo data will help settle the question of whether the most Mercury-like place on Earth is a volcano in Tanzania.

—Matthew R. Francis (@BowlerHatScience.org), Science Writer

Citation: Francis, M. R. (2026), A unique African volcano could solve a mystery on Mercury, Eos, 107, https://doi.org/10.1029/2026EO260176. Published on 2 June 2026.

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Source: Earth’s Future

The space industry is surging. In coming years, nearly 10,000 spacecraft are slated to launch into low-Earth orbit for a variety of purposes, such as global surveillance, space tourism, and satellite “megaconstellations” providing internet service.

Rocket engine exhaust, as well as the burnup of inactive satellites and rocket parts reentering Earth’s atmosphere, releases a suite of pollutants. These chemicals have long been considered to pose little threat to our climate, given the historically small size of the space industry. Now, the sector’s rapid growth will send its emissions skyrocketing—but scientists don’t yet have a clear picture of the environmental ramifications.

An analysis by Vliex et al. of rockets launched in 2022 revealed that spaceflight depletes the ozone layer and contributes to global warming, with a significant portion of this ozone loss attributable to nitrogen oxide emissions released by objects reentering Earth’s atmosphere.

The researchers calculated emissions from all 186 rockets launched in 2022, as well as all 472 objects—with a combined total mass of nearly 5,000 tons—that reentered the atmosphere that year. They conducted computational simulations of each launch’s trajectory and emissions at various altitudes up to 100 kilometers, and they calculated emissions released by object reentry. They also accounted for the effects of chemical reactions that occur in rocket exhaust plumes, which alter emissions’ chemical composition.

Incorporation of the calculated emissions into GEOS-Chem, a computational model of atmospheric chemistry, revealed their ozone-depleting and Earth-warming effects, with reentry emissions identified as playing a key role in ozone depletion. The researchers found that accounting for plume reactions reduced the estimated effects of spaceflight emissions, highlighting the value of considering plume chemistry in future assessments.

The analysis also underscored the varying effects of different rocket fuel types. Solid-state fuels, used recently in rocket boosters for NASA’s Artemis II mission to return astronauts to the Moon, appeared to cause the greatest amount of ozone depletion relative to propellant mass, while rocket-grade kerosene caused the greatest amount of warming.

On the basis of their findings, the researchers call for further research into reentry emissions and rocket plume chemistry as the space industry continues to expand and evolve. (Earth’s Future, https://doi.org/10.1029/2025EF007795, 2026)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2026), Rocket launches and reentries harm Earth’s ozone layer, Eos, 107, https://doi.org/10.1029/2026EO260183. Published on 8 June 2026.

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Editors’ Highlights are summaries of recent papers by AGU’s journal editors.

Source: AGU Advances

Solar eruptions can trigger geomagnetic storms that disrupt satellites, GPS, and power grids, affecting daily activities and technology. Therefore, it is extremely important to understand these storms in order to mitigate their impact. Previous studies mainly focused on interplanetary conditions.

Ghag et al. [2026] investigate the interaction between solar ultraviolet light (EUV) during storms and the Earth magnetic field, taking into account its misalignment and offset with respect to the Earth’s rotational axis, which depend on time. Such misalignment and offset induce variations in EUV exposure in turn influencing the ionosphere and its interaction with the magnetosphere.

The study applies the Multiscale Atmosphere-Geospace Environment (MAGE), a physics based fully coupled whole geospace model. The causal relationship between storm timing and storm effect is explored revealing insights on our capability to predict storm impact based on the time dependent Earth system state.

Citation: Ghag, K., Lotko, W., Pham, K., Lin, D., Merkin, V., Raghav, A., & Wiltberger, M. (2026). Universal time influence on stormtime magnetosphere ionosphere coupling. AGU Advances, 7, e2025AV002071. https://doi.org/10.1029/2025AV002071

—Alberto Montanari, Editor-in-Chief, AGU Advances

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Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

Today, NASA announced an agencywide realignment that includes combining related mission directorates to sharpen the agency’s focus on human spaceflight.

“This initiative reflects NASA’s extreme focus on executing the mission in direct support of the National Space Policy,” NASA Administrator Jared Isaacman said in a press release about the realignment.

The National Space Policy refers to Executive Order 14369: Ensuring American Space Superiority, which was released by the Trump administration in December 2025. The order sets national priorities of returning Americans to the Moon, establishing a lunar base, developing a nuclear reactor in space, developing the commercial space economy, and enhancing the United States’ national security space architecture.

NASA’s six existing mission directorates will be slimmed down to four. Exploration Systems Development and Space Operations will be combined into a new Human Spaceflight Mission Directorate and will facilitate human spaceflight in low-Earth and lunar space environments. Aeronautics Research and Space Technology will be folded into a new Research and Technology Mission Directorate, tasked with researching and developing nuclear power and propulsion. The structure of the Science Mission Directorate (SMD) and Mission Support Directorate remain unchanged at the time of publication. All directorate leaders will now report directly to the NASA Administrator (Isaacman) to ensure that each remains focused on their directorate’s new mission.

“There will be no reduction in force, no program cancellations, no closures, but we will achieve cost savings through more efficient execution and taking an active role in delivering the outcomes the world has been waiting for from NASA,” Isaacman said.

More Efficient?

At first glance, it is hard to see how combining four mission directorates into two, refocusing the missions of each, and pushing for increased efficiency and cost reduction will not result in some loss of talent either through positions being eliminated or individuals finding themselves in jobs they do not want to hold.

In a letter to NASA employees, Isaacman went into more detail about the specifics of this realignment and described how it will shift the agency’s internal bureaucratic authority away from directorates and toward NASA’s field centers. Prior to this, centers like Goddard Space Flight Center in Greenbelt, Md., and Johnson Space Center in Houston would need to compete for funding that had been appropriated to directorates based on the programs or missions they were tasked with.

A NASA source based in Houston told Ars Technica that the competition for funding “has been an absolute disaster.”

This new realignment “will adjust the funding distribution, so Centers have the financial support needed to sustain the baseline critical capabilities independent of near-term mission assignment,” Isaacman stated. “This shift will allow Center Directors to focus on maintaining the infrastructure, workforce, and capabilities required for current and future missions.”

Isaacman was unclear about when these changes will take effect, and policy analysts are unsure whether the realignment will be recognized by Congress through its appropriations process. The most recent Fiscal Year 2027 appropriations bill for NASA, which advanced out of the House Committee on Commerce, Justice, and Science on 13 May, allocates funding for six mission directorates, not four. The Senate appropriations committee is expected to release its proposed budget for NASA in the coming weeks, and the two bills must still undergo a lengthy reconciliation process.

In fiscal year 2026, Congress broke with the president’s budgetary priorities for NASA and passed a budget that ignored several of the administration’s proposed financial and mission cuts. Whether Congress will do the same this year and maintain the prior breakdown of directorates will become clear in the coming months.

—Kimberly M. S. Cartier (@astrokimcartier.bsky.social), Staff Writer

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org.

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Albert Einstein postulated in his 1905 theory of special relativity that the speed of light in a vacuum is constant. Ever since, that’s been one of the fundamental assumptions of physics.

Now Enbang Li, a physicist at the University of Wollongong in Australia, has challenged this idea by building a machine he says is capable of detecting changes in the speed of light as it crosses Earth’s surface. The findings suggest that light is, in fact, sped up by gravity, which could have implications for Earth science applications ranging from climate monitoring to mineral resource exploration.

An Old Conundrum

The idea that light is influenced by gravity is not new. Einstein’s ideas, which were further developed with his theory of general relativity in 1915, predicted massive objects in space would bend light with their gravitational grab. This theory was famously proven in 1919 when two independent teams measured starlight passing a solar eclipse at two different points on Earth’s surface and found the results matched Einstein’s predictions.

This bending of light’s path, according to general relativity, is achieved by a warping of the space-time fabric. Under this scenario, the speed of light remains constant—it just has to travel farther as it navigates the warped space-time around celestial bodies, so to a distant observer, it appears to have been slowed.

But what if light doesn’t navigate warped space-time and actually is slowed down or sped up by the gravity of large objects?

Li pointed out that Einstein himself was not always convinced the speed of light was constant. In 1911, he wrote a paper postulating that light speed changed depending on the gravity of objects it passed by. However, “when he published his general theory,” said Li, “he just abandoned this model.”

If the movement of light can be affected by gravity, Li reasoned, it might be possible to detect variations in its speed on a local level—such as an elevator shaft in a building on the campus of the University of Wollongong.

Raising the Big Issues

Gravity on Earth varies locally, depending on altitude, underground density, and topography. Gravity at the top of a tall building, for example, is measurably weaker than it is at the bottom.

With these variations in mind, Li installed an experiment in an elevator. It consisted of a coil of fiber-optic cable that if stretched out in one direction, would be 10 kilometers (6.2 miles) long. Laser beams were fired through the cables and then reflected back, thus traveling 20 kilometers (12.4 miles) before reaching an ultrafast photodetector. An oscilloscope measured the time it took for the beam to travel that distance. The experiment was run at the top of the shaft and at the bottom.

The biggest challenge, Li said, was filtering out all the surrounding environmental “noise,” such as changing temperature and humidity, electromagnetic disturbance, and building vibrations. Li designed a temperature control system, and the experiment was sealed in an enclosure with electromagnetic shielding to isolate air flows. Li ran the experiment and found light moved minutely faster at the bottom of the shaft than at the top.

Gravity Sensing on the Go

Next, Li took his research a step further by building a small, portable machine he claims can detect changes in the speed of light as it nears more gravitationally dense objects.

In this second experiment, Li positioned a moveable 72-kilogram (159-pound) weight near the machine. Light, he found, moved faster when the weight was near the machine than when it was farther away.

The results, which were published in Scientific Reports, are consistent with the variable speed of light model Einstein proposed in 1911, although Li’s preliminary results are much larger than that model predicts.

If proven, the findings would present a fundamental challenge to our understanding of both general and special relativity.

In the world of Earth sciences, they could lead to greatly improved gravity-sensing technologies. Because of their sensitivity to changes in mass, gravity sensors are used to map the seafloor and to locate underground mineral reserves. Gravity sensing can also improve our understanding of Earth’s climate as variations in the gravity field can be linked to factors like changes in ice mass and shifts in groundwater.

Currently, gravimeters are vulnerable to vibrations and movement, whereas Li’s machine, which has no moving parts, could even be used on board a plane or submarine.

“A Striking Claim”

Chris Stevens, a numerical relativist with the University of Canterbury in New Zealand, called the work “intriguing and ambitious.” While Stevens, who was not involved in the research, said that Li’s work is “well founded,” he noted that any observable effects of gravity on light on Earth would be “extraordinarily small” and therefore these results must be treated with caution.

“In my own research on observable gravitational phenomena,” he explained, “I usually require a few black holes colliding somewhere in the universe. Separating genuine gravitational signatures from environmental and instrumental noise will therefore be exceptionally demanding.”

Stevens said the implications of Li’s research, if validated, would be far-reaching. “The work is exciting because it pushes precision photonic measurement techniques into a regime where relativistic effects may become practically useful for geophysics and sensing applications.”

John Norton, an historian of physics at the University of Pittsburgh who was also not involved in the research, called the findings a “striking claim.” He was, however, skeptical of them, saying “if there is a coupling between light and gravity of magnitude greater than general relativity predicts, it is hard to see how the 1919 eclipse test and later studies of gravitational lensing would not have found it.”

Li acknowledged there is a long way to go before his device finds everyday use. Disentangling the intricacies of space and time, he said, is a vast challenge. “In physics, people still say gravity is a mystery. Light is another mystery. So if you put these two mysteries together, that’s going to be a giant mystery.”

—Bill Morris, Science Writer

Citation: Morris, B. (2026), How Einstein’s lost theory could help us find minerals, Eos, 107, https://doi.org/10.1029/2026EO260189. Published on 12 June 2026.

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Wind-driven waves on Earth move sediments and shape shorelines. They transport energy between the atmosphere and planetary surface and also mix bodies of liquid, affecting both chemistry and biology. On other worlds with surface liquids, either now or in the past, wind waves would likely perform the same function and so would play a key role in climate and astrobiological potential.

New research went back to the fundamentals and explored the conditions that can generate waves on worlds with different physical properties and different liquids, such as Titan, Mars, and select exoplanets.

“Wind waves are really interesting phenomena,” said Una Schneck, a planetary science doctoral student at the Massachusetts Institute of Technology (MIT) in Cambridge. “They’re basically the interface between how the atmosphere communicates with the landscape, especially at the coast.”

The Physics of Waves

Past models of wind generation on other planets struggled because they tended to start from preexisting models of Earth waves. Those models were developed to describe waves in Earth’s specific combination of gravity, atmosphere, and surface liquid, namely, water, said Schneck, who led the new research. Such models were sometimes tailored to describe a particular location and season. Adapting those models for conditions on other worlds, including other liquids like methane and sulfuric acid, always seems to leave traces of Earth behind.

However, the physics of what creates wind-driven waves should be universal, Schneck said, so the team went back to the basics of wave generation. They developed a wave model that explores the relationship between a world’s bulk properties, like gravity and air density, and liquid properties, like surface tension, to determine the wind strength needed to produce a wave.

The team “created this model that went back to the basic physics of waves, instead of just trying to fit to known wave conditions,” said Taylor Perron, an MIT geomorphologist and planetary scientist and coauthor of the research.

The model showed that the threshold wind speed to generate a wave is lower for liquids with less surface tension, which makes it easier to change the liquid’s shape. Higher air density provides more force to push against a liquid’s surface, and lower gravity makes it easier for a wave to rise up—both factors allow a weaker wind to create a wave. The team published these results in the Journal of Geophysical Research: Planets in April.

Waves on Other Worlds

The team first tested their model on the only set of wind and wave data we have—Earth. They used 20 years of wave and weather data for Lake Superior. The model found, correctly, that it takes wind speeds of 2.2 meters per second to generate waves on the lake’s surface and accurately predicted the height of waves for different wind speeds.

They then used the model to predict wave conditions on other worlds. They started with Mars, which likely had ancient oceans and lakes. Winds of 1.2 meters per second would have created waves in the lake that filled Gale Crater millions of years ago. A wave in Gale Crater would have been taller than a wave on Earth produced by wind of the same strength owing to Mars’s lower gravity.

The story is similar on Titan, the largest moon of Saturn. Waves in Titan’s hydrocarbon lakes would swell with a mere 0.5 meter per second of wind and would rise higher than an Earth wave under similar wind conditions. But they would travel much more slowly than Earth waves and would be spaced farther apart.

“The paper represents our best theoretical understanding of how we expect for waves to behave in a variety of environments,” said Jason Barnes, a planetary scientist at the University of Idaho in Moscow who was not involved with this research. “The movie of Titan waves is particularly awesome—very slow moving for such large amplitudes! Although I don’t expect waves to get that high ever in Titan’s sluggish atmosphere, it’s fun to be able to visualize what they might look like if they did.”

The team also explored wave-generating conditions on three Earth-sized exoplanets. The possible sulfuric acid lakes of the exo-Venus Kepler-1649 b would grow in winds of 5.3 meters per second but would grow to a height similar to that of Earth waves because of its Earth-like gravity. Water lakes on LHS 1140 b would grow in 2.7 meter winds, similar to those on Earth, but would not grow as high because of its higher gravity. And on 55 Cancri e, a lava world, it would take winds of 37 meters per second—a category 1 hurricane—to move tiny waves of molten rock.

“Would you be able to ever detect this? Is this a useful thing to think about, or is it just a fun thought experiment?” Schneck asked. “If the waves are tall enough, you should be able to detect a change in the polarization [of an exoplanet’s light curve] that would not only suggest that there is a liquid surface on that exoplanet, but that liquid surface has waves.…In theory, this is something that people could do.”

Will We See It? Not Soon

Right now, the only world known to have surface liquid other than Earth is Titan, but we don’t have the right observations of Titan to test the new model. The European Space Agency’s Huygens probe landed on the moon in 2005, but nowhere near the northern lake district. NASA’s Cassini mission (of which Huygens was a part) did not detect any waves but did observe a changing lake shore that hinted at wave activity.

It’s possible that Titan’s waves are seasonal and Cassini just didn’t have the right timing, Perron noted. Temperature changes during Saturn’s year could affect wind speeds and also the composition of Titan’s lakes, changing the conditions of wave generation.

Still, the wind speed needed to make a wave on Titan is so low that “it would be very surprising if waves never formed. It just may be difficult to catch them when they’re there,” he said.

“The best way to test this work would be to send a sea probe to float or motor on one of Titan’s big 3 seas—Kraken Mare, Ligeia Mare, or Punga Mare,” Barnes said. “Such a ‘buoy’ probe would be able to simultaneously measure both the sea conditions and the wind conditions, allowing for a comprehensive test of the model.”

Alas, no such mission is in the works, and the upcoming Dragonfly mission won’t travel near any lakes to test this theory either. A future Titan orbiter might provide that information, while a current or future Mars rover might yet gather evidence showing how lakes worked in that planet’s past.

“The improved understanding of waves from this paper might help to constrain the possibilities for wave erosion at the margins of bodies of water…thereby helping us to probe into the past climates of Mars and Titan,” Barnes said.

—Kimberly M. S. Cartier (@astrokimcartier.bsky.social), Staff Writer

Citation: Cartier, K. M. S. (2026), What winds whip up otherworldly waves?, Eos, 107, https://doi.org/10.1029/2026EO260165. Published on 21 May 2026.

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Editors’ Highlights are summaries of recent papers by AGU’s journal editors.

Source: Journal of Geophysical Research: Planets

Dust and water ice clouds are ubiquitous on Mars; they regulate the planet’s climate and can affect measurements of other atmospheric components. Constraining their spatial and temporal variability is also essential for improving Martian general circulation models.

Fedorova et al. [2026] use solar occultation measurements from the SPICAM infrared spectrometer on board the Mars Express orbiter to characterize nine Martian years (MY 28 through 36) of dust and water ice clouds. Because the spectrometer could not distinguish between these particles’ types, the researchers employ a new method integrating Mars Climate Sounder data and general climate model predictions to identify them.

The analysis reveals that the particles can reach altitudes up to 80 kilometers during perihelion, while their size remains relatively uniform with height. This suggests that Martian dust distribution is driven more by atmospheric dynamics and horizontal transport, capable of lifting and moving particles over vast distances, rather than by turbulent mixing against gravity alone.

The study also provides a detailed seasonal and spatial climatology of major Martian atmospheric features, including the Polar Hood Clouds, the Aphelion Cloud belt, and the Mesospheric Clouds. The detection of high-altitude clouds (70–90 km) during dust events confirms enhanced transport of water vapor into the upper atmosphere during both global and regional storms. These findings are consistent with simultaneous observations from the Atmospheric Chemistry Suite on the Trace Gas Orbiter.

These observations show that large-scale atmospheric dynamics, rather than local mixing alone, control how aerosols are distributed vertically on Mars, with important implications for the transport of water to the upper atmosphere and the planet’s climate evolution.

Citation: Fedorova, A. A., Luginin, M., Montmessin, F., Korablev, O. I., Bertaux, J.-L., Stcherbinine, A., & Lefèvre, F. (2026). Multiyear monitoring of aerosol vertical distribution on Mars by SPICAM IR/MEX. Journal of Geophysical Research: Planets, 131, e2025JE009388. https://doi.org/10.1029/2025JE009388  

—Arianna Piccialli, Associate Editor, and Beatriz Sanchez-Cano, Editor, JGR: Planets

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Source: AGU Advances

The Sun continuously blasts charged, magnetic field–carrying particles, or plasma, in all directions. This solar wind interacts with the magnetic fields and atmospheres of several of our solar system’s planets and other bodies, sculpting long magnetic tails of charged particles—magnetotails—that stretch into space behind them.

Magnetotails contain thin layers of electric current–carrying plasma sheets, which sometimes “flap” in an up-and-down waving motion. Spacecraft observations have revealed that flapping in Earth’s magnetotail can be driven by a process called magnetic reconnection, in which magnetic field lines rapidly break and then snap together in a new configuration, releasing stored energy. However, whether reconnection plays this same role beyond Earth has thus far been a mystery.

Wen et al. report the first evidence that magnetic reconnection may also trigger magnetotail flapping at Mars.

Unlike Earth, Mars lost its global magnetic field billions of years ago. But it still sports a magnetotail, thanks in large part to interactions between the solar wind and charged particles in its upper atmosphere. Strong magnetic fields embedded in certain patches of the Martian crust—remnants of its lost planet-wide field—also influence the magnetotail.

Until recently, Mars’s magnetotail could only be studied using observations from NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft. MAVEN showed that the Martian magnetotail is highly dynamic, with a structure that twists, shifts, and flaps—and from which charged particles may escape into space. But because MAVEN can observe only one part of the magnetotail at a time, it couldn’t identify what processes might trigger flapping.

Another spacecraft, China’s Tianwen-1 orbiter, has now provided a second set of eyes. The researchers analyzed simultaneous observations from the two spacecraft, finding that signatures of magnetic reconnection detected by MAVEN in the upstream part of the magnetotail tended to coincide with flapping events detected downstream by Tianwen-1.

Before or during flapping, the spacecraft also detected temporary, twisted plasma structures known as flux ropes. A similar link has previously been observed on Earth, and it suggests that flux ropes generated by magnetic reconnection upstream might propagate downstream, driving instabilities in the magnetotail’s plasma sheets and triggering flapping.

Though more research is needed to confirm these findings, they shed new light on how energy moves and is released in space around Mars—and possibly other planets and celestial objects. (AGU Advances, https://doi.org/10.1029/2026AV002343, 2026)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2026), What makes Mars’s magnetotail flap?, Eos, 107, https://doi.org/10.1029/2026EO260123. Published on 20 April 2026.

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The solar system is bathed in galactic cosmic rays: protons and atomic nuclei traveling, nearly at the speed of light, from all directions. Earth’s magnetic field and atmosphere shield us from most of this harmful radiation, but outside of that shelter, the bombardment is strong enough to prove a threat to astronauts.

But a new analysis of data from the Chang’e-4 lunar lander published in Science Advances revealed an extended cosmic ray shelter stretching from Earth at an unexpected angle at least as far as the Moon, though exactly how far is unclear. When the Moon passes through this shelter in its orbit of Earth, the lunar surface experiences a roughly 20% reduction in the galactic cosmic ray flux.

“We found Earth casts kind of a shadow in the galactic cosmic ray space,” said Robert F. Wimmer-Schweingruber, a space physicist at Kiel University in Germany. “This was unexpected, and to me that was the cool part of this paper.”

The surprise came in part because the shape of Earth’s magnetic field is well understood: It forms a strong protective region around the planet known as the magnetosphere, with a long “tail” shaped by the solar wind of charged particles streaming from the Sun.

“You would expect an effect inside the tail or as [the Moon goes] through the tail, but we find an effect of the tail ahead of the tail,” said Wimmer-Schweingruber. He noted that if the magnetotail is like a person’s shadow cast behind them by sunshine, this newly discovered bubble would be like if that shadow extended to the front of the person as well and tilted rather than lying along a line connecting Earth, the Sun, and the Moon.

“The observed region of reduced [galactic cosmic ray] flux on the sunward side of the Moon’s orbit outside the geomagnetic field where it is compressed by the solar wind is unexpected,” Brian Flint Rauch wrote in an email. Rauch, a cosmic ray physicist at Washington University in St. Louis who was not involved in the Chang’e-4 study, added that any reduction in cosmic ray exposure is noteworthy for potential astronauts on the Moon.

A 20% decrease in flux during part of the lunar orbit is unlikely to make a large difference in determining when it’s safest for astronauts go out onto the lunar surface. But it might help guide individual decisions in the moment because while spacesuits won’t protect astronauts from cosmic rays, the metal of a habitat or lander would.

Shelter from the Storm

The China National Space Administration’s Chang’e-4 spacecraft was the first successful mission to the lunar farside, landing in the Von Kármán crater on 3 January 2019. As part of its suite of scientific instruments, the probe carried the Lunar Lander Neutron and Dosimetry experiment (LND) developed by Wimmer-Schweingruber and collaborators at Kiel University in an astonishingly rapid 18 months. This detector was designed in part to gauge conditions for human exploration by measuring the radiation on the Moon’s surface, including cosmic rays.

LND collected data between January 2019 and January 2022. Though Apollo astronauts carried radiation dosimeters, those instruments did not provide detailed information about fluctuations in exposure, making LND the primary source for such information from the lunar surface. For that reason, it provided the best data on galactic cosmic rays, which consist mostly of protons accelerated to nearly the speed of light in the remnants of supernovas.

These protons arrive in the solar system from every direction, often undeflected by the magnetic fields of stars or planets. However, Earth’s magnetosphere is strong enough to repel many galactic cosmic rays in low orbit, where the International Space Station (ISS) resides. Meanwhile, measurements show the ambient radiation dose on the lunar surface is more than twice as high as on the ISS and nearly 200 times as high as on Earth, which is a matter of concern for long-term human presence on the Moon.

All of these reasons are why everyone was surprised when LND data revealed Earth’s magnetic protection extends far beyond the magnetosphere and at an angle to the line connecting Earth and the Sun. Lead author Wensai Shang of Shandong University in Weihai, China, worked out that the angle corresponds to the twisting of the Sun’s magnetic field.

“As the Sun rotates, it pulls the solar wind along the solar magnetic field,” Wimmer-Schweingruber said. “That produces a spiral.” Apparently, an unanticipated interaction between this twist in the solar magnetic field and Earth’s magnetic field produces the cosmic ray shelter revealed by LND.

Wimmer-Schweingruber noted that he was extremely skeptical that such results were possible at first. He warned Shang, a graduate student he worked with, that he might be wasting his time looking for cosmic ray anomalies in the Chang’e-4 data. It was only after Shang provided ironclad analyses ruling out other possibilities that he was swayed.

With the LND instrument shut off, researchers need other sources of data to continue the work. Wimmer-Schweingruber expressed particular interest in understanding how cosmic rays produce secondary radiation—especially neutrons, which are very dangerous to humans—when they impact the lunar soil. In the meantime, the general understanding of the radiation environment provided by Chang’e-4 shows we still have some surprises in store as humans explore the solar system.

—Matthew R. Francis (@BowlerHatScience.org), Science Writer

Citation: Francis, M. R. (2026), Moon mission data reveal unexpected cosmic ray “shadow,” Eos, 107, https://doi.org/10.1029/2026EO260137. Published on 4 May 2026.

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Source: AGU Advances

This is an authorized translation of an Eos article. 本文是Eos文章的授权翻译。

木星的闪电一直是行星科学家关注的焦点，因为它标志着风暴活跃的区域，研究人员可以在这些区域深入研究以进一步了解木星大气中的对流现象。

远距离观测闪电并非易事，因此科学家们将研究重点放在最容易观测的闪电上：夜间发生的强闪电。因此，一些研究得出结论，木星上的闪电都与地球上最强的闪电——“超级闪电”——类似。然而，这一结论最近受到了质疑，因为NASA朱诺号探测器上的高灵敏度星体追踪相机探测到了微弱的浅层闪电。

Wong等人进行了更深入的研究，重点观察了2021年和2022年木星北赤道带的闪电高度集中在一些强大的孤立风暴中的情形，研究人员将这些风暴称为“隐形超级风暴”。这种不寻常的气象条件使研究人员能够更精确地确定闪电的位置。

科学家们并没有仅仅关注可见光，而是利用了朱诺号探测器携带的微波辐射计和Waves实验的数据。朱诺号在过去十年中一直在环绕木星运行。无线电波只是闪电产生的电磁辐射的一种形式，但它却是一种特别有价值的信息来源，因为即使云层或其他大气成分阻挡了视觉信号，科学家们仍然可以对其进行研究。这种方法使研究人员能够超越其他研究人员以往关注的那些强烈的夜间闪电，去探索其他类型的闪电。

研究人员报告称，在这些隐形超级风暴中，闪电无线电脉冲的出现频率为每秒三次，这与之前一些夜侧成像研究中的闪电频率相似。然而，这些闪电的强度仍然存在争议。一些闪电的强度可能与地球大气层中发现的平均闪电强度相似。但由于所分析的木星闪电信号和地球闪电信号的无线电频率存在巨大差异，有些闪电的强度也可能是地球闪电的上百万倍。

—科学撰稿人Saima May Sidik (@saimamay.bsky.social)

This translation was made by Wiley. 本文翻译由Wiley提供。

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NASA's Transiting Exoplanet Survey Satellite (TESS) has released a new mosaic that offers its most complete view of the night sky yet. Captured over eight years, the all-sky mosaic includes 679 confirmed, newly discovered exoplanets and nearly 5,200 candidate exoplanets.

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Source: Journal of Geophysical Research: Planets

Orbital imaging has hinted that Mars may have carbon-containing rocks called carbonates on its surface. Carbonates on Mars could offer new insights into how water interacted with rock on the Red Planet, helping scientists learn more about its past. In addition, because carbonates on Earth are primarily produced by living organisms, these rocks are high-value targets in the search for signatures of past life on Mars.

NASA’s Perseverance rover has been traversing Mars since 2021, covering more than 41 kilometers, much of it within Jezero Crater in the Nili Fossae region. Previous orbital data indicated the crater contains carbonates, as well as abundant olivine, which can change to carbonate in the presence of water and carbon dioxide. Now Clavé et al. have analyzed spectroscopic data from Perseverance’s SuperCam instrument suite from multiple locations within Jezero Crater, providing clear evidence of carbonates on Mars, as well as detailed information on how the mineralogy varies between locations.

The authors confirmed the presence of both carbonates and olivine-bearing rocks throughout Jezero Crater and found a generally inverse relationship between the two minerals. By contrast, carbonates were generally positively correlated with the presence of hydrated silica. The researchers hypothesize that an ancient lake in the crater, along with potential hydrothermal activity, played a role in transforming olivine to carbonate. The varying amounts of carbonate and different alteration states seen today may have been caused by changing lake levels on Mars billions of years ago, the researchers suggest.

Amounts of carbonate by weight vary between locations, from 1%–3% in the Séítah unit to 6%–16% in the Eastern Margin Unit. Extrapolating to the entire regional olivine-rich unit, the researchers calculated it could contain as much as 1.1 × 10¹⁴ kilograms of carbon, or up to 0.4% of the current total mass of the Martian atmosphere. Overall, Mars’s crust could contain significant amounts of carbon, implying that widespread carbon sequestration may have cooled the planet significantly in the past. (Journal of Geophysical Research: Planets, https://doi.org/10.1029/2025JE009107, 2026)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2026), Carbon-rich rocks may have cooled the ancient Martian atmosphere, Eos, 107, https://doi.org/10.1029/2026EO260170. Published on 28 May 2026.

Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.