Saturn's moon Titan is the only other body in the Solar System with weather similar to Earth's. The large moon has a thick, nitrogen-rich atmosphere like Earth's, liquid on its surface, and a precipitation cycle. But instead of water, the surface liquid and the precipitation cycle are mainly based on methane.

Planetary scientists have questions about Titan's methane cycle, especially regarding the moon's northern hemisphere, where its hydrocarbon lakes are concentrated. The Cassini-Huygens mission examined that region during its mission, but left many questions unanswered. Titan's year lasts 29.45 Earth years, so the northern hemisphere experienced winter and spring the entire time that Cassini-Huygens was there.

In new research, scientists used the JWST and the Keck II telescope to observe Titan during 2022 and 2023, when the moon's northern hemisphere was experiencing summer. They gained new insights into Titan's methane cycle and other aspects of its atmosphere.

The research, published in Nature Astronomy, is titled "The atmosphere of Titan in late northern summer from JWST and Keck observations." The lead author is Conor Nixon, a planetary scientist from the Planetary Systems Laboratory at NASA Goddard Space Flight Center.

Titan has a thick atmosphere, and it's the only moon in the Solar System with one. Due to its cold surface and troposphere, methane can condense in the moon's lower atmosphere. "Methane therefore plays a similar meteorological role to water on Earth, evaporating from the surface and reaching the middle troposphere, where methane clouds form and rainfall occurs in changing seasonal patterns," the researchers explain in their article.

Titan is known for its thick, nitrogen-rich atmosphere, as seen in this true-colour Cassini image.

Image Credit: NASA/JPL-Caltech/SSI/Kevin M. Gill

"Titan is the only other place in our solar system that has weather like Earth, in the sense that it has clouds and rainfall onto a surface," Nixon explained in a press release.

In both worlds, convection drives the cycle. The Sun heats the surface and causes methane, or water in Earth's case, to evaporate and rise in the atmosphere. The temperature drops at higher elevations, and the vapour condenses and falls as rain.

"Together, these results provide a new, integrated look at the composition and meteorology of Titan's atmosphere in 2022 and 2023 from the upper atmosphere to the surface, at a season that was poorly documented by previous observations," the authors write in their research article.

One of the key questions facing scientists who study Titan's atmosphere concerns how the methane cycle changes through the seasons in different hemispheres. In this research, Nixon and his colleagues used the JWST's Mid-Infrared Instrument (MIRI) to detect the methyl radical CH₃. CH₃ has lost one of its hydrogen atoms and has an unpaired electron. That unpaired electron makes the radical highly reactive, and it typically has a very short lifetime because of it. CH₃ is the main product of methane breakup in Titan's atmosphere, and is also the key to forming ethane and other heavier molecules like hydrogen cyanide (HCN) and acetylene (C₂H₂).

JWST observations show how the methane cycle works in Titan's atmosphere. The moon has a thick, nitrogen-rich atmosphere that also contains methane. Sunlit and energetic protons from Saturn split apart methane, forming the methane radical CH₃. CH₃ is highly reactive and rapidly combines with other molecules or other CH₃ molecules, forming molecules like ethane (C₂H₆). Then methane, ethane, and other molecules precipitate out of the atmosphere and fall as liquids onto Titan's surface, where they collect in the northern hemisphere's lakes.

Image Credit: NASA, ESA, CSA, Elizabeth Wheatley (STScI)

They used the JWST's Near-Infrared Spectrograph to detect CO and CO2 emission bands and measured these species over a wide range of altitudes. They also used the infrared cameras on the JWST and the Keck II to image tropospheric clouds over the northern hemisphere as they evolved by altitude. Scientists have observed clouds rising convectively over the southern hemisphere, but never over the northern hemisphere.

This figure from the research shows the JWST's spectroscopy results from NIRSpec (top) and MIRI (bottom). Grey bands in the top image show Titan's atmospheric windows. Note the detection of CH₃ in the MIRI data, the first definitive detection of the methane radical in the moon's atmosphere.

Image Credit: Nixon et al. 2025, Nature Astronomy.

This is significant because Titan's methane seas are concentrated in the northern hemisphere. This research shows how the seas can be the source of methane evaporation that fuels the moon's methane cycle.

Titan's lakes or seas are concentrated in the northern hemisphere and have about the same surface area as the Great Lakes.

Image Credit: NASA / JPL-Caltech / Agenzia Spaziale Italiana / USGS, Public Domain.

This isn't the first time scientists have observed clouds in Titan's atmosphere, but it's the first time observations have revealed such powerful convection.

"Our new observations of methane clouds in Titan's troposphere during late northern summer on Titan add to a catalogue of previous detections recorded by ground- and space-based observations that trace the seasonal variation of Titan's weather over nearly a full year," the authors write. Cassini detected many clouds in the southern hemisphere, and ground-based telescopes have observed large cloud outbursts in the same region.

In the last summer solstice in the northern hemisphere in 2017, clouds were increasingly being detected, "but few indicated deep, moist convection," the authors write. "Our observations indicate a continuation of cloud activity into late northern summer, roughly in agreement with the behaviour at high southern latitudes during southern summer, and also indicate the occurrence of deep, moist convection extending to the tropopause over the region of Titan where most of the surface liquids exist," they explain.

This figure from the research article shows how clouds were detected over Titan's northern hemisphere. Arrows show the clouds as they change over time.

Image Credit: Nixon et al. 2025, Nature Astronomy.

The research also examines what these new insights into Titan's atmosphere could mean for its future.

When methane breaks up in Titan's atmosphere, some of it joins with other molecules and falls back to the surface; however, some hydrogen escapes into space. That means that without constant methane replenishment from some source, Titan's atmosphere will deplete methane over time. This happened on Mars, which is now a cold, dry world.

"On Titan, methane is a consumable. It’s possible that it is being constantly resupplied and fizzing out of the crust and interior over billions of years. If not, eventually it will all be gone and Titan will become a mostly airless world of dust and dunes," said lead author Nixon.

Press Release: 

• Webb's Titan Forecast: Partly Cloudy With Occasional Methane Showers

Research: 

• The atmosphere of Titan in late northern summer from JWST and Keck observations

Titan, the largest moon of Saturn, looks more Earth-like on its surface than any other place in the Solar System. With its thick atmosphere and liquid methane rain, it has lakes, rivers, sand dunes and seas. But appearances can be deceiving and in other ways, Titan is in fact a very alien world. One baffling difference, recently discovered, is that Titan's rivers do not seem to form deltas when they reach the sea.

Titan is the largest moon of Saturn. It was discovered in 1655 by Christiaan Huygens, and was the 6th moon to be discovered after our own, and the 4 Galilean moons around Jupiter. It is the second largest moon in the Solar System, and orbits Saturn at an average distance of roughly 1.2 million kilometers. Although it is larger than Mercury, it has less than half as much mass. It also has a thick, cloudy atmosphere, and until a few decades ago, that was almost all we knew.

A breathtaking view of Titan's mysterious hydrocarbon seas, where rivers end in deep pits, challenging our understanding of planetary geology.

Similarities with Earth

When the Cassini mission arrived, we learned that Titan was surprisingly similar to Earth. It has an atmosphere thicker than our own and is the only place in the entire universe, outside of Earth, where we have observed the presence of free-running liquids on the surface. Despite the extreme cold, it has weather systems complete with rain falling from the clouds.

This rain, when it lands, rolls downhill to form streams and rivers, which eventually empty out into lakes and seas. Like on Earth, these rivers carve channels unto the ground, forming river beds, and they carry sediment.

But despite these similarities, they are still very different worlds. Titan is a place of extreme cold. Being so far from the Sun, it doesn't receive a lot of warming sunlight, and it doesn't have a massive molten iron core. At these temperatures, water is frozen so hard that it is just another kind of rock. The liquids raining from the sky and flowing on the surface? Super-chilled ethane and methane.

Hydrology

On Earth, water circulates around the planet in a cycle. Liquid water gives up some of its molecules to the atmosphere, driven out by their internal heat energy, in a process we call evaporation. The water vapour in the atmosphere circulates around the globe until it finds a region where the pressure is high enough, the temperature low enough, that it condenses into tiny droplets around nucleation sites: specks of dust or airborne bacteria. Sometimes these droplets stay liquid, and combine to form larger and larger droplets, sometimes they freeze into ice crystals, but either way we can see them from the ground as clouds. If the droplets get big enough, they start to fall, and we get precipitation (rain, snow, hail, depending on conditions).

If the rain falls from low enough that it doesn't simply evaporate again, it reaches land and wets the ground. Some soaks into the soil, the rest trickles down to form small streams, which in turn combine to form rivers, and eventually flow into the sea (or not! Some rivers in arid areas simply fade away, either soaking into the parched earth or evaporating away entirely). As rivers flow, they erode the ground beneath them, carving river beds, and transporting silt. This silt can be deposited wherever the flow is slow, and eventually builds up enough to change the course of the river. When this happens at a river mouth, the mouth begins to block up with silt and the river eventually breaks a new path around the blockage. Over enough time, this happens often enough that you are left with the classic triangular river delta formation.

But for some reason, this doesn't seem to happen on Titan!

Cassini

Titan's thick soupy atmosphere makes it hard to observe any of these features. None of this would be known without Cassini's synthetic aperture radar (SAR). Unfortunately liquid methane and ethane are completely transparent to the SAR instrument, so many of the details are inferred. We don't observe rivers or seas directly, but instead we see what they've done to the ground beneath: river beds cutting across the landscape, emptying to large basins that make up lake and sea beds.

Given that Deltas are formed from silt accumulated over very long times, blocking up river mouths and forcing rivers to find new paths, you might expect these formations to be easy to spot. But researchers studying Cassini mission data have not found them.

"It's kind of disappointing as a geomorphologist because deltas should preserve so much of Titan’s history," said Sam Birch, an assistant professor in Brown University’s Department of Earth, Environmental and Planetary Sciences. "We take it for granted that if you have rivers and sediments, you get deltas. But Titan is weird. It’s a playground for studying processes we thought we understood."

The hunt continues

To test his assumptions, Birch developed a numerical model to process similar data from a more familiar world: Earth. The model simulated what Earth's underwater features might look like to the same SAR instruments, if they were under liquid methane and ethane instead of water, and confirmed that river deltas should have been easily visible.

"If there are deltas the size of the one at the mouth of the Mississippi River, we should be able to see it," Birch said. "If there are large barrier islands and similar coastal landscapes like those we see all along the U.S. Gulf Coast, we should be able to see those."

But when Birch and his colleagues returned to the Cassini data they did not find the missing features: Only two rivers, near the South Pole of Titan, showed possible delta formations. By their count based on the Cassini data, only 1.3% of large rivers on Titan terminate in deltas, compared to almost all comparable rivers on Earth.

We're unlikely to know for certain what's going on until another mission can be sent to Saturn to study its moons more closely. But Birch and his team do have some ideas: Perhaps the sea level rises and falls fast enough that the sediments are regularly submerged, washing the silt away before it has time to form a proper delta. Or possibly strong winds and coastal currents are doing the same thing. After all, radar imaging has also revealed deep river channels cut into the sea beds themselves, another mystery that hasn't yet been solved.

As usual, it will take more data, and a lot more hard work from planetary scientists to find answers.

"This is really not what we expected," Birch said. "But Titan does this to us a lot. I think that’s what makes it such an engaging place to study."

What steps can be taken to enhance in-situ resource utilization (ISRU) for future astronauts on Mars? This is what a recent study presented at the 56^th Lunar and Planetary Science Conference hopes to address as an international team of researchers investigated the reasons, benefits, and challenges of conducting ISRU on Mars. This study has the potential to help astronauts, scientists, engineers, and mission planners develop new methods for enhancing the survivability of future Mars astronauts while also maximizing mission success.

Here, Universe Today discusses this incredible research with Dr. Christoph Gross, who is a postdoctoral researcher at Freie Universität Berlin (Free University of Berlin) and lead author of the study, regarding the motivation behind the study, specific locations on Mars for ISRU purposes, and the importance of ISRU in future crewed Mars missions. Therefore, what was the motivation behind the study?

Dr. Gross tells Universe Today, “The main motivation is the prospect that one day humans will set foot on Mars and will need resources to survive there. It may be feasible for short duration stays to bring everything to Mars (comparable to the lunar Apollo missions), but for long duration missions at least propellant and water/oxygen resources are needed to sustain the landed crews.”

Based on a 2024 study by the same researchers, the team discussed the benefits of growing food on Mars for future crewed missions. Based on the EDEN ISS project in Antarctica that operated from 2018 to 2022 and managed by the German Aerospace Center, the team estimated amount of area required to produce the necessary amount of food for one crewmember over one year was between 40 m² to 65 m² (430 ft² to 700 ft²). Additionally, the team noted how growing plants on Mars could contribute to producing oxygen and removing carbon dioxide from the atmosphere.

The team also discussed various locations on Mars where resources could be exploited, including Juventae Chasma and Meridiani Planum, which the team notes possess hydrated minerals and uniform deposits, respectively. Juventae Chasma is a box canyon measuring 250 kilometers by 100 kilometers (155 miles by 62 miles) and located near the Martian equator just north of Valles Marineris, the latter of which is the largest canyon in the solar system. Meridiani Planum is a giant plain whose diameter stretches approximately 1,060 kilometers (659 miles) also located near the Martian equator and resides on top of hydrated sediments. But what other locations on Mars could be investigated for ISRU purposes?

“Our first study was in Juventae Chasma and more limited in Mawrth Vallis,” Dr. Gross tells Universe Today. “However, many places appear to be good candidates. Our investigations use remote sensing data from orbiting instruments. In Utopia Planitia, subsurface ice and salt deposits are suspected. However, remote sensing data is pretty sparse from this location, because the basin is so deep and the atmosphere thicker there, this makes the identification of specific minerals difficult.”

Dr. Gross continues, “Also, we try to find places which are also good candidates as landing sites, e.g. scientific interest, resources present, good location for transmissions to earth, good environmental conditions (not too extreme) etc. It also depends what kind of resources you are looking for. For example, larger impact craters could harbor important ore deposits too, depending on where they impacted (water-rich or water-poor substrate).”

ISRU involves using available resources to maximize mission success while also reducing the number of resources that are shipped from home. In the context of space exploration, this means astronauts on Mars would use available water from buried water ice for drinking, bathing, and producing oxygen from electrolysis. Since the atmosphere of Mars is incapable of having liquid water on its surface, buried water ice has become a target for future crewed mission plans.

Additionally, converting carbon dioxide, which is the dominant Martian atmospheric component, to oxygen using existing tools could reduce the amount of oxygen that is shipped from Earth. Finally, due to the harsh radiation that rains down on the Martian surface daily, Martian regolith could be used to cover habitats as a shield. Therefore, what is the importance of ISRU in future crewed Mars missions, and could it potentially lead to a self-sustaining settlement, someday?

“ISRU will make settlements self-sustaining one day,” Dr. Gross tells Universe Today. “There is no question about it. I think the fact that NASA demonstrated oxygen production with the MOXI experiment on the Perseverance rover shows in which direction the research is going. It will for sure not happen at once, but it will happen.”

Dr. Gross concludes, “I think it is important to note that many more exploration missions are needed since there are still so many question marks since we have only limited data from landed missions. This could be done with small and ‘cheap(er)’ scout missions that have specific tasks to discover and specify resource deposits.”

How will ISRU help enhance future crewed Mars missions in the coming years and decades? Only time will tell, and this is why we science!

• As always, keep doing science & keep looking up!

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If we could peel back the Moon's cratered crust and examine its mantle, we might find answers to some foundational questions about the Solar System. We lack the technological capability to excavate the Moon's mantle, but Nature has a way. A massive, ancient impact excavated material from deep beneath the Moon's crust and left it on the surface for us to find. It could help confirm the Moon's origins.

The Giant Impact Hypothesis (GIH) is the widely accepted explanation for the origin of the Moon. It proposes that a massive protoplanet about the size of Mars, named Theia, slammed into Earth about 4.5 billion years ago. The impact melted Theia and some of Earth, sending the material into orbit around Earth. Eventually, some of it coalesced into the Moon. The GIH was first proposed in 1946 but didn't attract much interest until decades later, when the Apollo lunar samples generated renewed interest.

This artist's illustration shows the protoplanet Theia impacting Earth more than 4 billion years ago.

Image Credit: By NASA/JPL-Caltech, Public Domain

The GIH says that the Moon formed primarily from the mantles of Earth and Theia. The lunar samples supported this idea because their isotopic ratios are similar to Earth's. However, surface rock has been exposed to space weathering and impacts for billions of years, altering its composition. What we need is a sample of the untouched mantle.

Ancient, massive impacts like the one that created the Imbrium Basin had the power to excavate material from the mantle and spread it around the crust near the impact site. China's Chang'e-5 mission returned its samples to Earth in 2020, and they contained glass beads. These beads are common near energetic impact sites, where the intense heat blasts rock and melts it into little pieces that land back on the ground near the site.

Normally, impact beads are made of crustal material. In new research, scientists from Curtin University, Nanjing University, and the Australian National University examined a large lunar bead from the Chang'e mission and found that it contains an unusually high level of magnesium oxide (MgO). This indicates that its parent rock is from the Moon's upper mantle.

The research, titled "A potential mantle origin for precursor rocks of high-Mg impact glass beads in Chang’e-5 soil," appears in Science Advances. The lead author is Chen-Long Ding from the School of Earth Sciences and Engineering at Nanjing University in China.

Evidence shows that all lunar rock contains glass beads. These beads are from lava eruptions and impacts and provide a collective record of lunar history. Samples from different sites on the Moon confirm this. However, the Chang'e 5 samples are different.

"The chemical compositions of most lunar impact glass beads reflect mixing of crustal components, including mare basalts, highlands rocks, and KREEP [from high concentrations of K, REE (rare earth element), and P]," the authors write in their research article. "However, a few glass beads in the soil from the Chang’e-5 mission have unusually high MgO contents that require distinct target compositions."

The young age of the glass beads indicates that they come from the impact melting of ultramafic rock, which generally contains higher amounts of MgO. "Of particular interest here is a group of glasses with MgO contents exceeding 18 wt% %," the authors write. "The high MgO concentrations clearly differentiate them from the local basalt and regolith at the Chang'e-5 landing site, which have MgO contents ~6.5 wt% %."

This figure from the research illustrates the high concentration of Magnesium Oxide in the Chang'e 5 glass beads in this study.

Image Credit: Ding et al. 2025, Science Advances.

Though these rocks could be from surface material, they don't appear similar to any of the Moon's known lithologies. "Alternatively, these high-Mg beads might be sampling the upper mantle brought to the surface by the Imbrium basin–forming event," the researchers write.

Professor Alexander Nemchin from the School of Earth and Planetary Sciences at Curtin University in Perth, Australia, is one of the study's co-authors. In a press release, Nemchin said, "These high-magnesium glass beads may have formed when an asteroid smashed into rocks that originated from the mantle deep within the Moon. This is exciting because we've never sampled the mantle directly before: the tiny glass beads offer us a glimpse of the Moon's hidden interior."

Professor Tim Johnson, also from Curtin's School of Earth and Planetary Sciences, is one of the paper's co-authors. Since the rocks' chemistry is so different from that of other lunar samples, they could've been excavated by a massive impact.

"One such event could be the formation of the Imbrium Basin, which is a huge crater formed more than 3 billion years ago," Professor Johnson said. "Remote sensing has shown the area around the basin's edge contains the kind of minerals that match the glass bead chemistry."

"This is a big step forward in understanding how the Moon evolved internally; if these samples really are pieces of the mantle, it tells us that impacts can excavate otherwise inaccessible mantle material to the surface," Johnson said.

While volcanism can produce similar types of glass beads, the authors explain why it's not likely that these beads are volcanic. The mission's sample includes other glass beads of various ages. For all of them to be volcanic, there must have been multiple volcanic eruptions in the region very early in the Moon's history. However, while impacts can spread their glass beads over a wide area, volcanoes don't have the same reach, and their glass beads tend to accumulate near the center of the eruption. There's no evidence of that accumulation. "Therefore, while the possibility of very young volcanism on the Moon is provocative, there is no geological evidence for this, and we interpret the high-MgO beads in the Chang'e-5 regolith to have an impact origin," they write.

These results can't confirm the Giant Impact Hypothesis. But they do support the idea that the Moon experienced a magma ocean phase during its formation, which the GIH predicts. This opens a window into the Moon's deeper interior that wasn't there before. Scientists will work with these results and see what they tell them about the Moon and the Solar System. The results may help them constrain lunar magma ocean crystallization models and determine whether the mantle is rich in olivine and pyroxene, as predicted.

"Understanding how the Moon’s interior is made helps us compare it to Earth and other planets," said co-author Professor Xiaolei Wang from Nanjing University. "It could even guide future missions, whether robotic or human, that aim to explore the Moon’s deep geology."

Press Release: 

• Glass beads offer a window into the Moon's hidden depths

Research: 

• A potential mantle origin for precursor rocks of high-Mg impact glass beads in Chang'e-5 soil

Auroral displays are breathtaking light shows that can be seen across high latitude skies, created by the interaction between the solar wind and a planet's magnetic field. High-energy particles from the sun—mostly electrons and protons—hurtle through space until captured by magnetic field lines, which funnel them toward the poles. There, these charged particles collide dramatically with atmospheric molecules, transferring energy that excites atoms and molecules to higher states. As these excited particles return to their ground state, they release their excess energy as the shimmering curtains of coloured light we know as aurora.

Stunning northern lights display

It’s not just Earth that enjoys auroral displays though, in particular, Jupiter’s auroras dwarf Earth's aurora creating vast light shows that could swallow our entire planet. Powered by the gas giant's colossal magnetic field—14 times stronger than Earth's—these polar displays glow with an intensity  never seen on Earth and never fully disappear. Unlike Earth's auroras, which depend primarily on solar wind, Jupiter generates much of its auroral energy internally through its rapid 10-hour rotation and interactions with its volcanic moon Io, which pumps tons of sulphur and oxygen into Jupiter's magnetosphere daily.

Auroral displays on Jupiter captured by the Hubble Space Telescope in 2016

(Credit : NASA)

Recent observations by the James Webb Space Telescope's (JWST) Near-InfraRed Camera on Christmas Day 2023, led by Jonathan Nichols from the University of Leicester, have leveraged the telescope's exceptional sensitivity to capture the rapidly changing Jovian auroral features with unprecedented detail, revealing new insights into these massive electromagnetic storms.

“What a Christmas present it was – it just blew me away! We wanted to see how quickly the auroras change, expecting it to fade in and out ponderously, perhaps over a quarter of an hour or so. Instead we observed the whole auroral region fizzing and popping with light, sometimes varying by the second.” - Jonathan Nichols, University of Leicester.

Further observations were completed using the Hubble Space Telescope and together, the observations of Jupiter's auroras revealed that emissions from the trihydrogen ion (H3+) fluctuate much more dramatically than previously thought, offering new insights into the heating and cooling mechanisms of Jupiter's upper atmosphere.

However, the team encountered a mystery: the brightest infrared emissions captured by JWST had no corresponding features in Hubble's ultraviolet imagery. This suggests an apparently impossible phenomenon—what Nichols describes as "a tempest of drizzle," where large quantities of very low-energy particles somehow create intense auroral brightness visible only to JWST, leaving researchers baffled about the underlying mechanisms that could produce such contradictory observations.

Artist impression of the James Webb Space Telescope

The team acknowledge more work is required to investigate the discrepancy between the observations. They now hope to use additional JWST sessions to compare with NASA's Juno spacecraft data, hoping to solve the mystery.. These findings could prove valuable for the European Space Agency's Juice mission—which is currently traveling to Jupiter—to examine the gas giant's auroras using seven scientific instruments, including two imaging systems. They hope the study will improve our understanding of the interactions between Jupiter's magnetic field, atmosphere, and the charged particles from its moons, particularly Io.

Source : 

• Webb reveals new details and mysteries in Jupiter’s aurora

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How can artificial intelligence (AI) be used to advance mapping and imaging methods on other planets? This is what a recent study presented at the 56^th Lunar and Planetary Science Conference hopes to address as a lone researcher investigated using machine learning models to enhance mapping and imaging capabilities from orbital images obtained from the Mars Reconnaissance Orbiter (MRO) Context Camera (CTX), which is currently orbiting Mars. This study has the potential to help scientists, engineers, and the public better understand the benefits of AI in conducting more advanced science, specifically regarding global images around Earth and other worlds.

Here, Universe Today discusses this incredible research with Dr. Andrew Annex, who is a Senior Science Systems Engineer at the SETI Institute, regarding the motivation behind the study, the next steps in developing these machine learning models, and the importance of using machine learning models to improve upon existing methods. Therefore, what was the motivation behind the study?

“The primary motivation behind my work was the desire to accelerate scientific discovery and inquiry and enhance the scientific return from existing Mars datasets,” Dr. Annex tells Universe Today. “Many studies of Mars start by the simple identification of features on the surface and figuring out where they are. This is typically achieved by a scientist literally looking at images, many hundreds to thousands of images, manually. This process, however, can be very slow and tedious when looking at the surface at moderate to high resolution, as there is simply a lot of ground to cover.”

For the study, Dr. Annex evaluated how current image analysis methods could potentially be improved using machine learning models and tools, including content-based image retrieval (CBIR), OpenAI CLIP (Contrastive Language-Image Pre-training), and cloud computing architecture. The purpose of CBIR is to take a starting image and scan a database for similar images by scanning the image content.

OpenAI has become a leading research company with the goal of enhancing AI to benefit humanity in our everyday lives, with ChatGPT arguably being its most used and well-known model. OpenAI CLIP is a machine learning model designed to learn how to compare images and text while dealing with large datasets. Cloud computing uses a network of remote servers to manage large amounts of data, including mobile technologies, databases, storage, applications, and more.

In the end, Dr. Annex successfully used machine learning models to analyze global CTX mosaic images on Mars, including search and identification of specific image similarities across the Red Planet. While noting this research could open doors for improvements, including specific search queries, Dr. Annex emphasized machine learning models could be used on planetary surfaces across the solar system.

“What I built, in the end, is a basic visual search engine, that makes it possible to search the surface of Mars at the pixel resolution of CTX,” Dr. Annex tells Universe Today. “The work isn’t a single model answering a specific question that is typically seen in other ML [machine learning] research in planetary science. It’s an application of software (and machine learning) to make it possible to search the data quickly for many different things rapidly.”

The first image from a Mars orbiter occurred on July 15, 1965, by NASA’s Mariner 4 spacecraft, which returned strips of code that scientists and engineers colored based on the code number, along with returning the first black & white orbital image on July 16. That historic mission revealed that Mars was not the watery and tropical landscape that scientists dreamed about since Percival Lowell declared Mars to have living inhabitants in the early 20^th century.

Since then, Mars orbiters from several nations have sent back incredible images of the Red Planet, revealing a world that once held oceans and rivers of liquid water possibly billions of years ago. Due to the tireless work of these robotic explorers, the entire surface of Mars has been imaged, and some in incredible detail, by NASA’s Context Camera and High Resolution Imaging Science Experiment (HiRISE) camera, respectively. Therefore, what is the importance of using machine learning models to improve upon existing image analysis methods for Mars?

Dr. Annex tells Universe Today, “I think the importance is that over the past 25+ years, while computing power has increased, so has the amount of data we have to look at to answer our scientific questions, but also our speed at using this data has not accelerated. Existing techniques have not kept pace because these techniques aren’t necessarily computational, but conventional and critical by-eye image analysis and geologic interpretation. Many revolutionary scientific discoveries for Mars occurred when seeing the surface at a higher resolution than was available before. But now different, important questions about Mars can now be asked with a complete picture of the surface that the CTX global mosaic provides.”

Dr. Annex continues, “But seeing the whole surface at 5 meters per pixel isn’t achievable for a single individual, again it’s simply a lot of area to look at and hold in your mind. Machine Learning is important not just for speed, but perhaps more critically for flexibility in the task you are automating in ways that conventional computational image analysis isn’t practical for or are simply too slow for given the amount of data you need to examine and the time available. I don’t see machine learning replacing all image analysis, but I see it as another tool in the toolbelt. One that can be used to complement and enhance existing methods and analysis.”

How will machine learning help improve Mars image analysis in the coming years and decades? Only time will tell, and this is why we science!

• As always, keep doing science & keep looking up!

Binary asteroid systems, in which a large asteroid is orbited by a smaller satellite, are a growing field of interest. In recent years, this has included the asteroid Didymos, a 765-meter-diameter (2,510 ft) Near-Earth Asteroid (NEA) with an orbiting companion (Dimorphos). This moonlet was targeted by the Double Asteroid Redirect Test (DART), a kinetic impactor designed to test a promising technique for planetary defense. Similar binaries have been found across a wide array of small body populations in the Solar System and are being characterized by observatories and spacecraft.

To date, 13 asteroids measuring more than 100 km (62 mi) in diameter have been detected that have confirmed satellites. Interestingly, asteroid satellites are generally found around those with rapid rotations and an elongated shape. Previous models suggest that these satellites could be generated by impacts, but much remains unknown about how these systems came to be. By combining impact simulations, the team was able to track how spin and shape are related to collisional circumstances.

The research was led by Kevin J. Walsh, a Senior Research Scientist at the Southwest Research Institute (SwRI) in Boulder, Colorado. He was joined by researchers from the Johns Hopkins University Applied Physics Laboratory (JHUAPL), the Observatoire de la Côte d'Azur, Charles University, the Space Research and Planetary Sciences at the University of Bern, and the University of Tokyo. The paper describing his team's findings recently appeared online and is being reviewed for publication in the Astrophysical Journal Letters.

Asteroids are essentially material left over from the formation of the Solar System roughly 4.6 billion years ago. Therefore, the study of binary asteroid systems can provide important information regarding the collisional history of different asteroid populations. Changes in the orbital properties of the satellites can also provide insight into the internal properties of the primary. Similarly, differences in binary properties between asteroid classes may provide insight into the internal properties of different types of large asteroids and their formation process.

It is generally accepted that impacts are responsible for binary asteroid systems, since collisions are inevitable for large asteroids. Furthermore, investigations of Main Belt Asteroids like Ceres and Vesta (performed by the Dawn spacecraft between 2011 to 2018) have noted impact craters and basins. Previous research that modeled asteroid impacts, disruption, and reaccumulation has shown that satellite formation is a possible consequence. As Walsh told Universe Today via email:

"By 'impacts,' I simply mean that a large asteroid gets hit by some smaller asteroid. It builds a nice, big crater, and some of the ejected debris gets caught in orbit. The concept is sound, as we know, big asteroids get hit all the time. We also know that some get hit so hard that they literally break up – we see that in large families of asteroids that have very similar orbits and identical physical properties. However, the models never really explained why the ejecta doesn't just come back and hit the large asteroid. That is what simple physics suggests should happen if the target is a big, spherically symmetric object and the crater is relatively small."

Research has shown that the properties of asteroid satellites are highly dependent on the primary's size. For example, asteroids larger than 100 km (62 mi) in diameter typically have small satellites (<0.1 times the size of the primary). In addition, five of the 13 known systems have multiple satellites, with 130 Elektra having three. Meanwhile, fewer satellites have been observed around asteroids that are ~10 and 100 km (6.2 to 62 mi) in diameter, while those that are more than ~300 km (186.5 mi) appear to have none.

"What really caught our attention was a few things: first, the asteroids with satellites were all elongated and NOT spherical, and second, they were all rotating pretty fast," said Walsh. "We also noticed which asteroids didn’t have satellites, which is most of the ones with really big families of asteroids that would have been liberated in huge impacts. This data combined suggested that 'impacts' wasn’t enough to explain things, but that we needed to understand what types of impacts and the key mechanism that led some ejecta to end up as satellites and some to escape and become part of a larger asteroid family."

For their study, the team conducted simulations of asteroid impacts, which resulted in a wide range of post-impact shapes. These relied on a hydrodynamics code, which models the big shockwave and initial breaking of the target object. This was followed by an N-body granular dynamics code that simulated the gravity of the new fragments, how they interacted with each other, and the resulting shape and spin of the post-impact primaries. Lastly, they performed a long-term simulation to see how the smaller fragments orbited their primaries over time.

Ultimately, their results showed a correlation between satellite formation and the shape and spin of the largest remaining remnant. As Walsh explained:

"They revealed that it wasn’t about how big/energetic the impacts are, but rather about the angular momentum (from pre-impact spin of the target, or applied rotation from an oblique impact) that can produce the odd-shaped primary and a bunch of satellites on stable orbits. We could also dig deeper and figure out where the material was likely to originate from inside the parent body, and found that it was typically all located 10-20 km (6.2 to 12.4 mi) deep."

These last findings are particularly significant since they predict how the observation and study of asteroid satellites will provide valuable insight into material deep within their primaries. Since an asteroid's interior is naturally shielded from solar and cosmic radiation and the vacuum of space, scientists would be studying material as it was when the Solar System was still forming. In addition, their study clarifies many unanswered questions about this less-understood population of asteroids.

"It tells us why we don't see satellites around every big asteroid (they do all get impacted a lot!), and why we don't see them around parent asteroids with huge asteroid families," said Walsh. "It also helps us understand the genetic relationship between the primary and the satellite. Finally, it could help us search deeper for more satellites that have not yet been observed since we now know what the key properties of the primary body should be."

Several space missions are planned for the near future that will rendezvous with binary asteroids to learn more about the origin and evolution of the Solar System. These missions will also provide more information on the orbital mechanics of asteroid populations, which will help inform planetary defense. In addition, facilities like the Vera C. Rubin Observatory are expected to dramatically increase the list of candidate systems in the coming years.

Further Reading: 

• arXiv

More than sixty years ago, the Search for Extraterrestrial Intelligence (SETI) officially began with Project Ozma at the Greenbank Observatory in West Bank, Virginia. Led by famed astronomer Frank Drake (who coined the Drake Equation), this survey used the observatory's 25-meter (82-foot) dish to monitor Epsilon Eridani and Tau Ceti - two nearby Sun-like stars - between April and July of 1960. Since then, multiple surveys have been conducted at different wavelengths to search for indications of technological activity (aka. "technosignatures") around other stars.

While no conclusive evidence has been found that indicates the presence of an advanced civilization, there have been many cases where scientists could not rule out the possibility. In a recent paper, veteran NASA scientist Richard H. Stanton describes the results of his multi-year survey of more than 1300 Sun-like stars for optical SETI signals. As he indicates, this survey revealed two fast identical pulses from a Sun-like star about 100 light-years from Earth, that match similar pulses from a different star observed four years ago.

Dr. Stanton is a veteran of NASA's Jet Propulsion Laboratory (JPL), whose work includes participating in the Voyager missions and serving as the Engineering Manager of the Gravity Recovery And Climate Experiment (GRACE) mission. Since retiring, he has dedicated himself to the Search for Extraterrestrial Intelligence (SETI) using the 76.2-cm (30-inch) telescope at the Shay Meadow Observatory in Big Bear, California, and a multi-channel photometer he designed. The paper describing his survey's findings appeared in the journal Acta Astronautica.

For years, Stanton has used these instruments to observe more than 1,300 Sun-like stars for optical SETI signals. Unlike traditional SETI surveys that have used radio antennas to search for evidence of potential extraterrestrial transmissions, optical SETI looks for pulses of light that could result from laser communications or directed-energy arrays. This latter example has been considered in recent years thanks to Project Starshot, NASA's Directed Energy Propulsion for Interstellar Exploration (DEEP-IN) concept, and similar interstellar mission concepts.

As Stanton indicated, the field of optical SETI traces its roots to a 1961 study by Schwartz and Townes. They reasoned that the best way an extraterrestrial intelligence (ETI) could send an optical signal that outshone their star would be with intense nanosecond laser pulses. These pulses are searched for using special equipment in infrared wavelengths, high-resolution spectra, or visible light. As Stanton related to Universe Today via email, his SETI search differs from conventional optical surveys:

"My approach is to stare at a single star for roughly 1 hour using photon counting to sample the star’s light at what is considered a very high time-resolution for astronomy (100 microsecond samples). The resulting time series are then searched for pulses and optical tones. The instrument uses readily available off-the-shelf components that can be assembled into a PC-based system. I’m not sure if anyone else is doing this with a significant time commitment. I am not aware of any discovery of similar pulses."

After years of searching, Stanton reported an unexpected "signal" when observing HD 89389, an F-type star slightly brighter and more massive than our Sun, located in the constellation Ursa Major. According to Stanton's paper, this signal consisted of two fast, identical pulses 4.4 seconds apart that were not revealed in previous searches. He then ran comparisons against signals produced by airplanes, satellites, meteors, lightning, atmospheric scintillation, system noise, etc.

As he explained, several things about the pulses detected around HD89389 made them unique from anything seen previously:

"a. The star gets brighter-fainter-brighter and then returns to its ambient level, all in about 0.2s. This variation is much too strong to be caused by random noise or atmospheric turbulence. How do you make a star, over a million kilometers across, partially disappear in a tenth of a second? The source of this variation can't be as far away as the star itself.    

b. In all three events, two essentially identical pulses are seen, separated by between 1.2 and 4.4 seconds (the third event,  found in an observation on January 18^th of this year, was not included in the paper). In over 1500 hours of searching, no single pulse resembling these has ever been detected.

c. The fine structure in the star's light between the peaks of the first pulse repeats almost exactly in the second pulse 4.4s later. No one knows how to explain this behavior.

d. Nothing was detected moving near the star in simultaneous photography or in the background sensor that easily detects distant satellites moving close to a target star. Common signals from airplanes, satellites, meteors, birds, etc., are completely different from these pulses."

A re-examination of historical data for similar signals revealed another pair of pulses detected around HD 217014 (51 Pegasi) in 2021. This main-sequence G-type star is located about 50.6 light-years from Earth and is similar in size, mass, and age to our Sun. In 1995, astronomers at the Observatoire de Haute-Provence detected an exoplanet orbiting this star, a hot gas giant that has since been named Dimidium. This was one of the first exoplanets ever detected, and the first time an exoplanet was discovered around a main-sequence star.

At the time, said Stanton, the signal was dismissed as a false positive caused by birds. However, a detailed analysis ruled out this possibility for all the pulses observed. Other possibilities that Stanton explores include diffraction caused by the Earth's atmosphere, possibly due to a shock wave. However, this is unlikely since shockwaves would have had to occur with perfect timing to coincide with both optical pulses. Other possibilities include starlight diffraction by a distant body in the Solar System, partial eclipses caused by Earth satellites or distant asteroids, and "edge diffraction" by a straight edge (as described by the Sommerfeld Effect).

There's also the possibility that a gravity wave could have generated these pulses, which requires additional consideration. Another interesting possibility is that it could be the result of ETI. As Stanton indicated, whatever modulated these stars' light must be relatively close to Earth, implying that any ETI activity must be within our Solar System. However, Stanton stresses that more data is needed.

"None of these explanations are really satisfying at this point," he said. "We don't know what kind of object could produce these pulses or how far away it is. We don't know if the two-pulse signal is produced by something passing between us and the star or if it is generated by something that modulates the star's light without moving across the field. Until we learn more, we can't even say whether or not extraterrestrials are involved!"

There are several examples of Optical SETI (OSETI) or LaserSETI, including the collaborative effort launched by Breakthrough Listen and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) Collaboration. However, Stanton's method presents many opportunities for future SETI surveys, which could search for similar examples of optical pulses. To that end, he suggests two approaches that could reveal more about this phenomenon and help astronomers place tighter constraints on their possible causes:

"Look for events using arrays of synchronized optical telescopes. If the object is moving between the star and us, this approach should tell us how fast it is moving normal to the line of sight, and potentially its size and distance. [Also,] it would be very interesting if the star's light is modulated without an object moving across the field. Observing events with telescopes separated by a few hundred kilometers might show that any separation in the time each pulse arrives is due only to differences in the light time from the star to each telescope. Then, unless the variation could somehow be attributed to the star itself, we would have even more to explain!"

Further Reading:

• Acta Astronautica

Our local star the Sun is a vast sphere of electrically charged gas (plasma) and is the beating heart of our Solar System, bathing our world in life giving heat and light 150 million kilometres away.  A main-sequence star, it’s composed primarily of hydrogen and helium, converting four million tons of matter into energy every second through nuclear fusion in its core. With surface temperatures reaching 5,500°C and a diameter 109 times that of Earth, the Sun has illuminated our planet for 4.6 billion years and will continue to shine for (hopefully) another 5 billion more before expanding into a red giant.

The Sun in white light showing sunspots and faculae

Of the many events visible on the Sun, solar storms are powerful eruptions of energy from that hurl charged particles and electromagnetic radiation into space at tremendous speeds. These violent phenomena begin as solar flares or coronal mass ejections (CMEs) on the Sun’s visible surface, where magnetic field lines twist, break, and explosively reconnect. When directed toward Earth, these storms can interact with our planet's magnetic field, triggering geomagnetic disturbances that create spectacular auroras but also pose serious risks to modern infrastructure.

Solar Orbiter view of the Sun showing solar flares

A year ago, NASA and other government agencies gathered to simulate responding to such events due to the potential risks yet their simulations were interrupted by the most powerful solar storm in over two decades. The G5 level event that was named the Gannon storm (named after space weather physicist Jennifer Gannon,) struck Earth on 10 May 2024. It transformed their tabletop exercise into a real-world response. While this powerful solar event—capable of damaging satellites, overloading electrical grids, and endangering astronauts—didn't cause catastrophic damage, it provided valuable insights to help prepare for future solar threats.

The storm caused widespread disruptions on Earth and in space. High-voltage lines tripped and transformers overheated in the US and GPS-guided tractors went off course. In the air, increased radiation risk and communication issues forced trans-Atlantic flights to reroute. The storm also heated the thermosphere to over 1,100°C, causing it to expand and create strong winds that pushed heavy nitrogen particles higher. This expansion increased atmospheric drag on satellites, causing some to lose altitude or deorbit early, and forcing others to use more power to stay in orbit and avoid debris.

“Not all farms were affected, but those that were lost on average about $17,000 per farm” - Terry Griffin, a professor of Agricultural Economics at Kansas State University.

Rare global auroral displays were also triggered, with over 6,000 sightings reported from 55 countries across all continents. In Japan, unusually high magenta auroras puzzled scientists until they found, through photo analysis, that these lights appeared about 600 miles above Earth—much higher than usual. A study concluded the rare colour came from a mix of red and blue auroras caused by oxygen and nitrogen molecules lifted by the storm's heating and expansion of the upper atmosphere. NASA called it a unique and exceptional event.

The Sun’s intense activity didn’t just affect Earth—it also hit Mars. NASA’s MAVEN spacecraft observed auroral displays covering Mars between May 14 and 20. The solar particles disrupted the star camera on the Mars Odyssey orbiter, causing it to shut down temporarily, and create visual "snow" in images from Curiosity’s cameras. Most notably, Curiosity recorded its highest-ever radiation spike, with levels that would have exposed astronauts to the equivalent of 30 chest X-rays.

The launch of MAVEN by an Atlas V rocket on 18 November 2013

(Credit : NASA)

The Gannon storm stands as a stark reminder of the Sun’s immense power, spreading aurora to unusually low latitudes and earning the title of the best-documented geomagnetic storm in history. It has provided an unprecedented set of data that scientists are still analysing a year later. From unexpected radiation surges on Mars to tractor disruptions in the American Midwest, the storm highlighted both the beauty and the vulnerability of life under the influence of our local star. As researchers continue to unravel the Gannon storm’s many effects, the lessons learned will shape future strategies for protecting technology, infrastructure, and even astronauts from the Sun.

Source : 

• https://www.eurekalert.org/news-releases/1083377

Mars, the fourth planet from the Sun, has fascinated us for generations. This cold, dusty world features some of the Solar System's most dramatic landscapes, including massive canyons, towering volcanoes, and sprawling plains. While Mars appears dry and barren today, mounting evidence indicates it once had significant amounts of liquid water. Orbital imagery shows ancient riverbeds and what appear to be dried lake beds, while rovers have identified minerals that typically form in watery environments. These discoveries suggest Mars experienced a warmer, wetter period billions of years ago before transforming into the arid planet we observe today.

A full globe image of Mars showing its many features

A team of international scientists from China, Australia, and Italy investigated this very mystery; whether liquid water—crucial for habitability and once abundant on ancient Mars—still exists beneath the planet's surface. Their research addresses fundamental questions about potential Martian life and future human exploration.

"Water involves profound questions about life and humanity's future on the Red Planet” - lead researcher Dr. Hrvoje Tkalčić from the Australian National University.

The international geophysicists and geologists analysed seismic data from NASA's InSight mission, examining waveforms from two major meteorite impacts and Mars' largest recorded quake to investigate the planet's crustal structure. Their research revealed a significant low shear-wave velocity anomaly 5.4-8 kilometres beneath the surface, strongly suggesting the presence of liquid water at the base of Mars' upper crust. The team calculated this potential water reservoir could contain the equivalent of a 520-780 meter deep global water layer if spread across the entire Martian surface.

InSight Lander in Mars-Surface Configuration

(Credit : NASA/JPL-Caltech/Lockheed Martin)

The research team cautions that their estimate of Martian subsurface water is based only on data from beneath the InSight lander and doesn't account for regional variations or potentially primordial water elsewhere in the crust. Their groundbreaking detection of substantial liquid water 5.4-8 kilometres below the surface of Mars provides crucial insights into the planet's water cycle and habitability, though confirmation will require additional seismic missions.

This study transforms our understanding of Mars, suggesting the Red Planet didn't simply lose its water—it hid it underground. The discovery of a potentially vast subsurface reservoir challenges long-held assumptions about the evolution of Mars and dramatically improves prospects for future human exploration. With accessible water potentially available beneath the surface, establishing sustainable Martian outposts becomes more feasible.

View of Jezero acquired by Perseverance's left navigation camera

(Credit : NASA)

As space agencies plan ambitious crewed missions to Mars in coming decades, these findings will shape mission objectives, landing site selections, and resource utilisation strategies. Beyond practical implications, this research opens exciting new possibilities in astrobiology, as subsurface liquid water environments could provide sheltered habitats where Martian microorganisms might have survived or even thrived long after the surface became inhospitable.

Source :

• The quest for Martian water: seismic velocity anomalies suggest liquid water at depth

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Hunting for exoplanets has transformed from science fiction to cutting-edge science fact in recent decades. Scientists use ingenious methods to spot these distant worlds, often looking for the subtle dimming of stars as planets cross their faces or the slight gravitational wobble planets induce in their host stars. Modern observatories like NASA's Transiting Exoplanet Survey Satellite and the James Webb Space Telescope have turned this cosmic treasure hunt into an age of discovery revealing thousands of worlds beyond our Solar System.

Artist impression of an exoplanet around a distant star

The European Space Agency's PLATO mission will soon join this flotilla of planet-hunting spacecraft. Set to launch in 2026, PLATO (PLAnetary Transits and Oscillations of stars) features an array of 26 high-precision cameras working together to continuously monitor vast regions of the sky. Unlike previous planet hunters, PLATO will specialise in finding and characterizing Earth-like planets orbiting in the habitable zones of Sun-like stars by simultaneously tracking the faint dimming of light from over 200,000 stars.

Artist impression of PLATO

(Credit - By ESA/ATG medialab)

PLATO is rapidly taking shape with 24 of its 26 sophisticated cameras now mounted on the spacecraft's optical bench to ensures precise alignment. The remaining two "fast" cameras will be installed in the coming weeks, while the spacecraft's supporting structure is being assembled in parallel at OHB in Germany.

"It's rewarding to see the progress we have made from last year when the work to mount the cameras started: with 24 cameras now in place, we see Plato taking its proper shape," - Thomas Walloschek, ESA's PLATO Project Manager.

PLATO's observational prowess comes from its strategic camera arrangement: 24 "normal" cameras positioned in four groups of six, each aimed at slightly different parts of the sky to collectively monitor about 5% of the celestial sphere simultaneously. Complementing these are two "fast" cameras that rapidly image the brightest stars within the same field and provide positioning coordinates to the spacecraft's guidance system. Meanwhile, engineers at OHB are constructing PLATO's service module, which houses the essential computers, orientation controls, propulsion systems, power distribution, and communication components. The integration of the camera-carrying payload module with this service module is scheduled for summer at OHB's facilities.

Main building in Bremen

(Credit - Marko Schade)

Building the PLATO satellite requires a new level of precision as engineers carefully mount its delicate cameras to ensure perfect alignment for detecting the faintest signals from distant stars. The sophisticated instruments are designed to capture minute brightness variations that occur when exoplanets transit their host stars. Beyond planet hunting, PLATO will revolutionize stellar science by monitoring "starquakes"—subtle brightness fluctuations that reveal a star's internal structure and age. This comprehensive approach, combining space observations with ground-based telescope follow-ups, will allow scientists to determine both the sizes and masses of newly discovered exoplanets.

Source :

• Plato grows its many eyes

On February 18th, 2021, NASA's Perseverance rover landed in Jezero crater on Mars. This feature was selected because liquid water may have once flowed into it, as indicated by the delta feature at its western edge. Since landing, Perseverance has been exploring the region's geology and past habitability, including the samples it collected for eventual return to Earth. Analyzing these samples will provide new clues about Mars' warm and watery past and address whether life once existed there.

However, the delta fan is not the only significant feature in the Jezero crater near where the Perseverance rover landed. There's also the recently-named Jezero Mons, a mountain that dominates the southeastern horizon, identified in Perseverance rover images. According to new research, lava flows possibly originating from this mountain could have shaped the geology of the crater floor. According to their findings, the analysis of the Perseverance samples could also reveal clues about ancient Mars when it was still geologically active.

The study was led by Sara C. Cuevas-Quiñones, a PhD Planetary Science student from the School of Earth and Atmospheric Sciences (EAS) at the Georgia Institute of Technology (Georgia Tech) and Brown University. She was joined by EAS Professor Dr. James Wray, EAS Assistant Professor Frances Rivera-Hernández, and Jacob B. Adler, a Research Assistant Professor with the School of Earth and Space Exploration at Arizona State University (SESE-ASU). The paper describing their findings appeared on May 3rd in the journal Nature.

As Cuevas-Quiñones and her colleagues note in their paper, the detection of clay and carbonate minerals on Jezero Crater's floor supports the conclusion that the sedimentary deposits on the crater's western edge are the result of aqueous activity that took place roughly 3.8 to 3.5 billion years ago. In addition, satellite observations have revealed a set of non-sedimentary geologic materials that cover most of the Jezero crater's floor. This includes data obtained by the Mars Odyssey's Thermal Emission Imaging System (THEMIS) and the Mars Orbiter Laser Altimeter (MOLA) aboard the Mars Global Surveyor.

Spectral features observed in the Jezero crater indicated the presence of olivine [(Mg, Fe)₂SiO₄], a mineral commonly found in igneous rocks and a primary part of Earth's upper crust. The spectra also indicated the presence of magnesium carbonate (MgCO₃) and hydrated minerals. As Prof. Wray told Universe Today via email, this constitutes evidence that Jezero Mons was once an active volcano:

Volcanoes are built 'from the ground up', as successive layers of lava and ash erupt and spread from the source vent; so if Jezero Mons is indeed a volcano (as we argue), then its simple presence would be evidence that it was once active, to have built up the mountain that we see looming above the crater rim today. There are also possible flows of material visible on the mountain's northwestern flank extending down onto Jezero crater's southeastern floor, which could have emerged when the volcano was active. And finally, there are the volcanic rocks that Perseverance encountered in its traverse across the crater floor - we can't say for sure that those came from Jezero Mons, but they imply that there was an active volcano somewhere nearby in the region's past! And Jezero Mons seems like the most visually apparent candidate to us.

Before the Perseverance rover landed, there were several theories about Jezero's curious geology, ranging from lakebed sedimentary deposits, sandstone formed by wind-blown sand, or volcanic ash. However, observations by the Perseverance rover of the Séítah formation revealed lightly altered olivine cumulate rock. These minerals form when olivine crystals accumulate and settle from a magma or lava flow. These mineral deposits predate the formation of the crater's delta features.

Similarly, the darker-toned rock unit known as the Máaz formation dominates the central crater floor, which shows spectral signatures of pyroxene, another mineral associated with volcanic outflows.

As Wray told Universe Today, the presence of volcanic and aqueous activity would have had a significant impact on the crater:

"Given the clear evidence for river channels and sediment fans, before Perseverance landed some thought most of the material on the floor might have been sedimentary rocks, perhaps lake deposits. But the first rocks explored with the rover appeared pretty clearly volcanic (or at least igneous, i.e. cooled from a magma). If Jezero Mons had been identified and more widely discussed before the rover landed, then maybe this wouldn't have been so surprising. The timing of Jezero Mons's activity is pretty uncertain, but there is indeed evidence from the rover (and from orbital mapping of materials across the crater) that episodes of water flow and volcanism interleaved with each other over time."

To evaluate this hypothesis, the team consulted datasets from the Mars Reconnaissance Orbiter's (MRO) High Resolution Imaging Science Experiment (HiRISE) and other orbiter missions. Infrared hyperspectral mapping of the northern and eastern flanks of the mountain showed widespread pyroxene-bearing materials and a mixture of low- and high-calcium pyroxenes at the summit. Meanwhile, the mixing of pyroxene-rich materials and underlying bedrock was visible in several areas of the crater around the mountain's western flank.

Similarly, the team measured the mountain's morphometry and compared it to similarly sized volcanoes identified on Earth and Mars. While they found that most Martian shield volcanoes are significantly larger than Jezero Mons, a similarly sized mountain with a summit crater believed to have once been an explosive volcano has been observed in Thaumasia Planum. In addition, two of the first mountains identified as potential composite volcanoes—Zephyria and Apollinarus Tholi—are even more similar in size to Jezero Mons.

For an Earth-based comparison, the team measured Antarctica's Mt. Sidley, which has been identified as a potential analog for the Argyre Mons volcanic cone, but is more similar in size to Jezero Mons. As Wray noted, the timing of Jezero Mons's activity and the origin of volcanic rocks in the crater remain open questions. Nevertheless, evidence obtained by Perseverance and orbiters that have mapped the Jezero Crater suggests that episodes of water flow and volcanism interleaved with each other over time. 

"In terms of what that means for habitability, volcanic eruptions-like any natural disaster-often have immediate negative effects, but can have longer-term benefits for the evolution of ecosystems on Earth," Wray added. "In particular, a sizable volcano so close to the Jezero crater paleolake implies subsurface heat that could have prolonged the stability of any liquid water there, a potential boon for habitability on a planet 50% farther from the Sun than Earth."

The timing of Mars' volcanism and its possible effect on habitability cannot be answered until a Mars sample-return mission can be mounted. Unfortunately, scientists will have to wait a while due to the cancellation of the NASA/ESA Mars Sample Return (MSR) mission. Currently, the plan is to return them via a crewed mission planned for the 2030s, though experts predict that such missions will happen no sooner than 2040. But as Wray explained, the analysis of the Perseverance samples will be a major game-changer:

"The sample return will provide major, unique insights into Jezero crater's history, such as solving the "pretty uncertain timing" problem mentioned above: we can date igneous rocks quite precisely in Earth-based labs by measuring rare isotopes of trace elements, but this is very difficult to do with miniaturized rover instruments. Fortunately, the sample return from Jezero is exactly what NASA has planned! I can't imagine another place on Mars from which it would be much more valuable to return samples, so I hope we get them back, whether the US continues to lead on that effort or someone else steps up instead."

In the meantime, says Wray, another rover (or possibly a crewed mission) to the Jezero Crater would address these two questions. This mission could set down between Jezero Mons and the crater's floor, allowing it to explore the mountain and volcanic deposits directly. The team also suggests that additional high-resolution mapping could greatly increase our knowledge of the eastern side of Jezero. This could be accomplished using existing orbital assets or by future spacecraft like the ESA's LightShip/SpotLight mission under consideration.

Further Reading: 

• NCBI

Some parts of the Moon are more interesting than others, especially when searching for future places for humans to land and work. There are also some parts of the Moon that we know less about than others, such as the Irregular Mare Patches (IMPs) that dot the landscape. We know very little about how they were formed, and what that might mean for the history of the Moon itself. A new mission, called the LUnar Geology Orbiter (LUGO), aims to collect more data on the IMPs and search for lava tubes that might serve as future homes to humanity. 

IMPs are a set of "enigmatic volcanic landforms", according to a new paper from Petr Bro¸ of the Czech Academy of Sciences and his co-authors. Ninety-one of these features have been found so far, and they are typically characterized by a topographical depression that can range from a few hundred meters to a few kilometers in width. They have two main features - a relatively smooth mound surrounded by a "hummocky and block floor". 

Interestingly, they have significantly fewer impact craters than the surrounding area, suggesting they are either really old or really young, depending on the processes that created them. Understanding those processes is one of LUGO's primary mission objectives.

Fraser discusses how to explore lava tubes.

The other primary mission objective is to gather more data about lunar lava tubes. These features of the lunar landscape are also hotly debated, but they could potentially be critical to the future human settlement of the Moon. Estimates of their features, such as size and depth, vary widely and could dramatically differ on whether they will be helpful to lunar colonists or not.

Enter LUGO—the proposed orbiter that will collect more data than ever before on these features. In its current suggested form, it has four instruments, each of which will contribute unique data to its scientific mission.

According to the paper, the first and most important instrument is a ground-penetrating radar. This instrument will look through the lunar surface to map out the subsurface domain of both the IMPs and lava tubes. For IMPs, it can detail the interface between bedrock and regolith and show the subsurface structure of the feature. Similarly, it can detect differences in dielectric properties between open cavities underground and the surrounding rock in lava tubes, creating a subterranean picture unlike anything ever captured on the Moon.

How will we be able to explore lava tubes? Fraser tries to answer that question.

A hyperspectral camera will help collect age-related data on the regolith surrounding lava tubes and inside IMPs. It can also perform some basic spectroscopy, allowing scientists to estimate the composition of the regolith in the areas of interest.

The last two instruments, a narrow-angle camera (NAC) and a LiDAR sensor, will combine to create an accurate topographical map of the features of interest. The NAC, in particular, can provide very high-resolution images of the features, helping to determine their age and potentially their formation mechanisms.

The mission plan calls for multiple passes over the six largest IMPs, all of which are over 1,000m in diameter. Other, smaller IMPs and lava tubes are considered secondary targets, as are other interesting lunar geological features such as lunar domes and "floor-fractured craters." 

LUGO could provide crucial data for the design of ground-based lava tube explorers, like the one Fraser discusses in this video.

LUGO won't be acting alone, though - three other missions are slated in the next few years that would complement its scientific objectives. NASA's DIMPLE lander is planned to take radioisotopic measurements of the age of regolith at its landing site. LunarLeaper, scheduled for launch by ESA around 2030, would also carry a ground-penetrating radar, but would be based on the surface rather than in orbit, and therefore would have a relatively limited range. Trailblazer, another orbital mission, could also help fine-tune the spectra and signals analysis required by LUGO's operators.

Ultimately, LUGO has yet to be funded, and therefore, it has a long way to go until launch. But if it is funded, it seems well-placed to provide lots of additional insight into the geological formation process and features of the Moon at a level of detail we've never had before. If we do end up using some of that data to plan the location of future lunar bases, the people living in them will surely be thankful.

Learn More:

• P Bro¸ et al - LUnar Geology Orbiter concept to study lunar Irregular Mare Patches and lava tubes from orbit
• UT - The Entrance of a Lunar Lava Tube Mapped from Space
• UT - It's Time to Study Lunar Lava Tubes. Here's a Mission That Could Help
• UT - Mapping Lava Tubes on the Moon and Mars from Space