Category: 7. Science

New fear unlocked: spontaneous black hole implosion.

Fresh research predicts that planets may be able to accumulate enough dark matter to suddenly form a black hole at their core. As the intruder grows, catastrophe unfolds: it would then devour the world from the inside out, becoming a black hole with the same mass as its unfortunate meal.

The findings, published as a study in the journal Physical Review D, are terrifying to contemplate. The intent, however, wasn’t to haunt our dreams but to demonstrate a potential new avenue for studying dark matter, the invisible substance that accounts for 85 percent of all mass in the universe. Oh, and this would only affect gas planets, so the Earth is safe for now. 

“In gaseous exoplanets of various sizes, temperatures, and densities, black holes could form on observable timescales, potentially even generating multiple black holes in a single exoplanet’s lifetime,” co-lead author Mehrdad Phoroutan-Mehr, an astronomer at the University of California, Riverside, said in a statement about the work. 

“These results show how exoplanet surveys could be used to hunt for superheavy dark matter particles, especially in regions hypothesized to be rich in dark matter like our Milky Way’s galactic center.”

Astronomers still don’t know what dark matter actually is. We know it exists because of its gravity, which governs the formation of the largest structures in the cosmos. Beyond that, it’s a veritable apparition.

The prevailing model suggests that dark matter is made up of weakly interacting massive particles, or WIMPs, which are heavy and slow enough that they clump together and form enormous dark matter “halos” that give birth to entire galaxies. WIMPs also don’t interact with ordinary matter and even light, rendering them effectively invisible. It’s hypothesized that these particles can annihilate each other upon colliding, releasing gamma rays that should be detectable, but so far, efforts to detect signs of these collisions have come up short.

In the study, the researchers go down a different route and propose that dark matter particles are heavy but don’t annihilate. Near the center of the galaxy, where dark matter concentrations are the highest, that means that a massive gas giant like Jupiter could capture some of these dark matter particles in its core. There, rare interactions between the dark matter and ordinary matter could result in the dark matter particles losing their speed, clumping together, and becoming dense enough to spawn a black hole. This could happen in as little as ten months, they found.

Surprisingly, this may not necessarily spell doom for whatever world is unlucky enough to find itself incubating a cosmic monster.

“Whether a black hole inside a planet survives or not depends on how massive it is when it first forms,” Phoroutan-Mehr told Physics World. If it starts off small enough, it may wink out before it has a chance to feed and grow.

“Interestingly there is also a special in-between mass where these two effects balance each other out,” Phoroutan-Mehr added. “In that case, the black hole neither grows nor evaporates — it could remain stable inside the planet for a long time.”

If these black hole planets exist, we should be able to detect them somewhere near the center of the galaxy. Exoplanets, then, could be a valuable way for exploring and testing our understanding of dark matter. But finding these planets would be easier said than done. For one, they’d be gravitationally indistinguishable from ordinary planets. And while they would be unusually hot, this can be explained by a myriad of less extraordinary phenomena.

“Rather, our point is that if detailed studies reveal temperatures that cannot be explained by ordinary processes,” Phoroutan-Mehr told Physics World, “then dark matter could be considered as one possible — though still controversial — explanation.”

In lieu of that, other findings could be extremely encouraging — like a tiny black hole, for instance.

“Discovering a black hole with the mass of a planet would be a major breakthrough,” Phoroutan-Mehr said in the statement. “It would support the thesis of our paper and offer an alternative to the commonly accepted theory that planet-sized black holes could only form in the early universe,” he explained, referring to what’s known as primordial black holes.

Ideally, we’d document a large population of these diminutive singularities. That “could offer strong evidence in favor of the superheavy non-annihilating dark matter model,” Phoroutan-Mehr said in the statement.

As to whether our solar system’s planets could meet their end by spawning a black hole, it’s unlikely. We’re about 26,000 light years from the center of the Milky Way — not that there aren’t other cosmic horrors we should be concerned about, of course.

More on space: The Object at the Center of Jupiter Is So Strange That It Defies Comprehension

Two spacecraft mimicked a solar eclipse to capture rare images of the Sun’s corona. The mission also helps predict hazardous space weather.

During a natural solar eclipse, heliophysicists have a rare opportunity to investigate the Sun’s corona, the outermost layer of its atmosphere, in ways that are not normally possible.

The Sun’s inner regions shine so intensely that they overwhelm the faint light of the corona, making it invisible to most astronomical instruments. Only when the Moon passes in front of the Sun and casts a shadow on Earth can the corona be seen. However, eclipses are uncommon, brief, and visible only along narrow tracks across the planet. As a result, researchers must go to great lengths to position their instruments in the right place at the right time to study these fleeting events.

To overcome these limitations and deepen understanding of the Sun, scientists at the European Space Agency have developed and launched a new probe capable of producing artificial eclipses.

Meet Proba-3

The spacecraft, named Proba-3, is designed to mimic the effect of a natural solar eclipse. One of the probes, which appears nearly circular from the front, orbits closer to the Sun and blocks its intense central light, functioning much like the Moon during an eclipse. This creates a shadow that falls onto a second probe equipped with a camera to capture images of the artificial eclipse.

Coordinating two spacecraft so that one consistently casts a shadow on the other is a highly complex challenge. Proba-3 serves as a test mission to demonstrate this precise formation-flying technology, which will be essential for many future space projects.

The methods being developed could support upcoming missions, such as spacecraft designed to dock with and remove inactive satellites or advanced telescopes that place sensitive instruments far from their primary mirrors.

At the same time, the mission offers researchers an added advantage: the ability to capture valuable images of the Sun’s corona, giving scientists new opportunities to study its structure and behavior.

An immense challenge

The two satellites launched in 2024 and entered orbits that approach Earth as close as 372 miles (600 kilometers) – that’s about 50% farther from Earth than the International Space Station – and reach more than 37,282 miles (60,000 km) at their most distant point, about one-sixth of the way to the Moon.

During this orbit, the satellites move at speeds between 5,400 miles per hour (8,690 kilometers per hour) and 79,200 mph (127,460 kph). At their slowest, they’re still moving fast enough to go from New York City to Philadelphia in one minute.

While flying at that speed, they can control themselves automatically, without a human guiding them, and fly 492 feet (150 meters) apart – a separation that is longer than the length of a typical football stadium – while still keeping their locations aligned to about one millimeter.

They needed to maintain that precise flying pattern for hours in order to take a picture of the Sun’s corona, and they did it in June 2025.

The Proba-3 mission is also studying space weather by observing high-energy particles that the Sun ejects out into space, sometimes in the direction of the Earth. Space weather causes the aurora, also known as the northern lights, on Earth.

While the aurora is beautiful, solar storms can also harm Earth-orbiting satellites. The hope is that Proba-3 will help scientists continue learning about the Sun and better predict dangerous space weather events in time to protect sensitive satellites.

Adapted from an article originally published in The Conversation.

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Scientists are about to unleash a powerful new weapon in the hunt for dark matter, the mysterious substance that accounts for around 85% of the “stuff” in the universe. Like a super-weapon developed by a stereotypical supervillain, this new dark matter detector is hidden over a mile deep beneath the French Alps.

This highly sensitive detector, developed by an international team of researchers including scientists from Johns Hopkins University, will expand the search for potential dark matter particles beyond its current parameters. It could thus provide evidence for the existence of a particular dark matter candidate particle, or the detector could help rule out some suspects.

There are more than 12,000 active satellites circling Earth at the moment, a growing figure that has nearly doubled in less than three years. This recent boom in the satellite industry has been a major headache for astronomers, with bright satellites appearing as streaks in telescope images of the universe and tarnishing views of the night skies.

A new paper reveals that satellite constellations are brighter than the recommended limits set forth by astronomers, with only one company adhering to the guidelines. The paper, appearing in the preprint server arXiv, compares the observed brightness magnitudes of satellite constellations in Earth orbit with brightness limits established by the International Astronomical Union’s (IAU) Center for the Protection of the Dark and Quiet Sky (CPS).

Nearly all the satellites were found to exceed the limit of +7 brightness magnitude, thereby interfering with observations of the cosmos. The brightest satellites belonged to Texas startup AST SpaceMobile, with its BlueWalker constellation exceeding a brightness magnitude of +2.

Saving our views of space

Due to more affordable access to space, the cost of launching satellites to orbit is at an all-time low. In response to the growing number of satellites, the IAU established its center in 2022 in an effort to ensure satellite constellations do not interfere with the study and enjoyment of the night skies.

Although there are no official regulations in place, the CPS established recommendations for maximum acceptable brightness for satellites orbiting below 341 miles (550 kilometers). The IAU established a maximum brightness of +7 magnitude for professional astronomy and below +6 magnitude as the aesthetic reference so it does not impact the public’s ability to stargaze without interference from satellites.

SpaceX’s Starlink constellation, which includes more than 8,000 satellites currently in orbit, is of major concern to astronomers due to its size and brightness levels. SpaceX has been working with the IAU and other astronomy groups to mitigate the effects of its satellites on astronomical observations after its satellites photobombed a number of telescope images. Early versions of Starlink satellites were at a brightness magnitude of around +3, but SpaceX’s modifications have decreased that number to +5 or +6.

The paper, however, does raise concern that although the Starlink Minis are four times larger than the new generation Starlinks, the Gen 2 Mini satellites orbit Earth at a lower altitude of 279 miles (450 kilometers). As a result, the mean apparent brightness of the newer Starlinks is greater despite the company’s mitigation efforts to decrease its satellite’s reflection.

The worst of the worst

SpaceX’s competitor, AST SpaceMobile, is the worst offender by far. The company’s BlueWalker satellites have an average apparent magnitude of +3.3, often outshining most objects in the night sky. The BlueWalker satellites boast an array that stretches across 693 square feet, the largest communications array ever deployed in low Earth orbit. AST SpaceMobile is seeking to build a constellation of 100 satellites.

While most companies violated the suggested guidelines, one company stuck to them. London-based OneWeb has 652 satellites in orbit with an average apparent magnitude of +7.85, meeting the adjusted limit considering their altitude of 745 miles (1,200 kilometers) above Earth’s surface.

The IAU’s center has only set forth suggestive guidelines so far, but it wants to expand its efforts to encourage governments and state officials to better regulate the booming industry. So far, the center’s calls have been largely ignored, suggesting regulations do need to be in place if we want to maintain our views of the skies.

Professor Tao Sun is harnessing macrophages’ appetite for cellular trash to find tumors and diseased cells in the brain and, with help from tiny excited bubbles, alert other immune cells to the fight.

Researchers at Northeastern University are using ultrasound to pair voracious debris-clearing blood cells with microscopic bubbles to control the immune system’s response to disease in the brain and beyond. 

Focused on ultra-hungry white blood cells called macrophages, assistant professor of biological engineering Tao Sun is harnessing the macrophage’s appetite for cellular trash to find tumors and diseased cells in the body and, with help from tiny excited bubbles, alert other immune cells to the fight.

“Scientists like to use the word ‘plastic’ to describe macrophages,” says Sun. “They change their behaviors all the time. They can be big fighters. They can also be resting, doing nothing, like a couch potato.”

This very changeability, Sun says, makes macrophages potent tools in the fight against cancer and other inflammation associated diseases. Sun’s most recent work, funded with $1.99 million through a Maximizing Investigators’ Research Award from the National Institutes of Health, is studying ways to inject tiny bubbles into the bloodstream and, after the bubbles latch on to macrophages, use ultrasound waves to control the bubbles.

Since ultrasound waves create real-time images, scientists will be able to see what’s happening inside the macrophage — an imaging breakthrough — and remotely change macrophage behavior. They can also track the cells as they move through the body.

Macrophages and their precursors, monocytes, work throughout the bloodstream and tissues to regulate immune defense and inflammation, Sun says. But this research is ultimately focused on their presence in the brain and how they travel there. As delicate as it is, the human brain is protected by specialized endothelial cells — a blood-brain barrier — to keep toxins out.

When macrophages are active, they fight inflammation, eating cancer cells and recruiting other immune cells. But their inactive state, Sun says, is an anti-inflammatory “healing” state. This condition actually helps cancer cells grow. 

By blasting ultrasound waves at the brain, he says, scientists will be able to make the bubbles vibrate and expand briefly. This movement reverberates, causing the bubbles to expand briefly and weaken the blood-brain barrier. With the newly developed bubble-carrying macrophages and ultrasound-opened blood-brain barrier, the external trigger may switch the macrophage state back to a cancer-fighting inflammatory state.

“With these living cell probes we can actually use ultrasound waves externally to control biological function,” Sun says. Switching macrophages to their inflammatory state creates a hostile environment for cancer, he says, but a conducive one for treatment.

“The first step is actually changing from the anti-inflammatory, the bad healing state, and turning it into the pro-inflammatory state, the best for fighting cancer,” he says. The next step, he says, would be to pair this method with drugs. 

“When we have ultrasound as external energy, we don’t really need surgery,” Sun says. “When you send ultrasound waves directly into the brain they provide spatial targeting to specific places inside the brain, whether there’s a tumor or other pathology related to Alzheimer’s or Parkinson’s.”

A new ultra-detailed map of the Sculptor Galaxy exposes stellar life and hidden structures, offering new insights into how small-scale processes influence entire galaxies.

Astronomers have unveiled a remarkable new view of the Sculptor Galaxy, producing a highly detailed image that exposes features never seen before. The achievement comes from observations with the European Southern Observatory’s Very Large Telescope (ESO’s VLT), which captured the galaxy in thousands of different colors at once. By gathering enormous amounts of data from every region, the team assembled a complete picture of how stars live and evolve across Sculptor.

“Galaxies are incredibly complex systems that we are still struggling to understand,” says ESO researcher Enrico Congiu, who led a new Astronomy & Astrophysics study on Sculptor. Reaching hundreds of thousands of light-years across, galaxies are extremely large, but their evolution depends on what’s happening at much smaller scales. “The Sculptor Galaxy is in a sweet spot,” says Congiu. “It is close enough that we can resolve its internal structure and study its building blocks with incredible detail, but at the same time, big enough that we can still see it as a whole system.”

The building blocks of a galaxy, which include stars, gas, and dust, shine in different colors of light. The more distinct colors captured in an image, the deeper the insight into a galaxy’s inner processes. Standard images usually display only a few colors, but the new map of Sculptor contains thousands. With this level of detail, astronomers can determine properties of the stars, gas, and dust such as their age, chemical composition, and movements.

To create this map of the Sculptor Galaxy, which is 11 million light-years away and is also known as NGC 253, the researchers observed it for over 50 hours with the Multi Unit Spectroscopic Explorer (MUSE) instrument on ESO’s VLT. The team had to stitch together over 100 exposures to cover an area of the galaxy about 65 000 light-years wide.

A Tool for Zooming In and Out

According to co-author Kathryn Kreckel from Heidelberg University, Germany, this makes the map a potent tool: “We can zoom in to study individual regions where stars form at nearly the scale of individual stars, but we can also zoom out to study the galaxy as a whole.”

In their first analysis of the data, the team uncovered around 500 planetary nebulae, regions of gas and dust cast off from dying Sun-like stars, in the Sculptor Galaxy. Co-author Fabian Scheuermann, a doctoral student at Heidelberg University, puts this number into context: “Beyond our galactic neighbourhood, we usually deal with fewer than 100 detections per galaxy.”

Because of the properties of planetary nebulae, they can be used as distance markers to their host galaxies. “Finding the planetary nebulae allows us to verify the distance to the galaxy — a critical piece of information on which the rest of the studies of the galaxy depend,” says Adam Leroy, a professor at The Ohio State University, USA, and study co-author.

Future projects using the map will explore how gas flows, changes its composition, and forms stars all across this galaxy. “How such small processes can have such a big impact on a galaxy whose entire size is thousands of times bigger is still a mystery,” says Congiu.

Reference: “The MUSE view of the Sculptor galaxy: Survey overview and the luminosity function of planetary nebulae” by E. Congiu, F. Scheuermann, K. Kreckel, A. Leroy, E. Emsellem, F. Belfiore, J. Hartke, G. Anand, O. V. Egorov, B. Groves, T. Kravtsov, D. Thilker, C. Tovo, F. Bigiel, G. A. Blanc, A. D. Bolatto, S. A. Cronin, D. A. Dale, R. McClain, J. E. Méndez-Delgado, E. K. Oakes, R. S. Klessen, E. Schinnerer and T. G. Williams, 12 August 2025, Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202554144

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Rocky material that impacted Mars lies scattered in giant lumps throughout the planet’s mantle, offering clues about Mars’ interior and its ancient past.

What appear to be fragments from the aftermath of massive impacts on Mars that occurred 4.5 billion years ago have been detected deep below the planet’s surface. The discovery was made thanks to NASA’s now-retired InSight lander, which recorded the findings before the mission’s end in 2022. The ancient impacts released enough energy to melt continent-size swaths of the early crust and mantle into vast magma oceans, simultaneously injecting the impactor fragments and Martian debris deep into the planet’s interior.

There’s no way to tell exactly what struck Mars: The early solar system was filled with a range of different rocky objects that could have done so, including some so large they were effectively protoplanets. The remains of these impacts still exist in the form of lumps that are as large as 2.5 miles (4 kilometers) across and scattered throughout the Martian mantle. They offer a record preserved only on worlds like Mars, whose lack of tectonic plates has kept its interior from being churned up the way Earth’s is through a process known as convection.

The finding was reported Thursday, Aug. 28, in a study published by the journal Science.

“We’ve never seen the inside of a planet in such fine detail and clarity before,” said the paper’s lead author, Constantinos Charalambous of Imperial College London. “What we’re seeing is a mantle studded with ancient fragments. Their survival to this day tells us Mars’ mantle has evolved sluggishly over billions of years. On Earth, features like these may well have been largely erased.”

InSight, which was managed by NASA’s Jet Propulsion Laboratory in Southern California, placed the first seismometer on Mars’ surface in 2018. The extremely sensitive instrument recorded 1,319 marsquakes before the lander’s end of mission in 2022.

Quakes produce seismic waves that change as they pass through different kinds of material, providing scientists a way to study the interior of a planetary body. To date, the InSight team has measured the size, depth, and composition of Mars’ crust, mantle, and core. This latest discovery regarding the mantle’s composition suggests how much is still waiting to be discovered within InSight’s data.

“We knew Mars was a time capsule bearing records of its early formation, but we didn’t anticipate just how clearly we’d be able to see with InSight,” said Tom Pike of Imperial College London, coauthor of the paper.

Quake hunting

Mars lacks the tectonic plates that produce the temblors many people in seismically active areas are familiar with. But there are two other types of quakes on Earth that also occur on Mars: those caused by rocks cracking under heat and pressure, and those caused by meteoroid impacts.

Of the two types, meteoroid impacts on Mars produce high-frequency seismic waves that travel from the crust deep into the planet’s mantle, according to a paper published earlier this year in Geophysical Research Letters. Located beneath the planet’s crust, the Martian mantle can be as much as 960 miles (1,550 kilometers) thick and is made of solid rock that can reach temperatures as high as 2,732 degrees Fahrenheit (1,500 degrees Celsius).

Scrambled signals

The new Science paper identifies eight marsquakes whose seismic waves contained strong, high-frequency energy that reached deep into the mantle, where their seismic waves were distinctly altered.

“When we first saw this in our quake data, we thought the slowdowns were happening in the Martian crust,” Pike said. “But then we noticed that the farther seismic waves travel through the mantle, the more these high-frequency signals were being delayed.”

Using planetwide computer simulations, the team saw that the slowing down and scrambling happened only when the signals passed through small, localized regions within the mantle. They also determined that these regions appear to be lumps of material with a different composition than the surrounding mantle.

With one riddle solved, the team focused on another: how those lumps got there.

Turning back the clock, they concluded that the lumps likely arrived as giant asteroids or other rocky material that struck Mars during the early solar system, generating those oceans of magma as they drove deep into the mantle, bringing with them fragments of crust and mantle.

Charalambous likens the pattern to shattered glass – a few large shards with many smaller fragments. The pattern is consistent with a large release of energy that scattered many fragments of material throughout the mantle. It also fits well with current thinking that in the early solar system, asteroids and other planetary bodies regularly bombarded the young planets.

On Earth, the crust and uppermost mantle is continuously recycled by plate tectonics pushing a plate’s edge into the hot interior, where, through convection, hotter, less-dense material rises and cooler, denser material sinks. Mars, by contrast, lacks tectonic plates, and its interior circulates far more sluggishly. The fact that such fine structures are still visible today, Charalambous said, “tells us Mars hasn’t undergone the vigorous churning that would have smoothed out these lumps.”

And in that way, Mars could point to what may be lurking beneath the surface of other rocky planets that lack plate tectonics, including Venus and Mercury.

More about InSight

JPL managed InSight for NASA’s Science Mission Directorate. InSight was part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supported spacecraft operations for the mission.

A number of European partners, including France’s Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR), supported the InSight mission. CNES provided the Seismic Experiment for Interior Structure (SEIS) instrument to NASA, with the principal investigator at IPGP (Institut de Physique du Globe de Paris). Significant contributions for SEIS came from IPGP; the Max Planck Institute for Solar System Research (MPS) in Germany; the Swiss Federal Institute of Technology (ETH Zurich) in Switzerland; Imperial College London and Oxford University in the United Kingdom; and JPL. DLR provided the Heat Flow and Physical Properties Package (HP³) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiología (CAB) supplied the temperature and wind sensors.

As carbon emissions rise, oceans absorb more CO₂, lowering pH and increasing acidity — a shift that threatens a wide range of marine species and ecosystems.

“Shark teeth, despite being composed of highly mineralized phosphates, are still vulnerable to corrosion under future ocean acidification scenarios,” said Maximilian Baum, lead author of the study and biologist at Heinrich Heine University Düsseldorf in Germany.

Maximilian Baum and his team collected 600 naturally shed teeth from 10 blacktip reef sharks (Carcharhinus melanopterus) at the Sea Life Oberhausen aquarium in Germany.

While most sharks continuously lose and replace their teeth, the replacement rate varies by species from a few days to several weeks.

For the experiment, researchers selected 16 intact teeth and 36 slightly damaged teeth and placed them in two separate 20-liter tanks for eight weeks, each with different pH conditions. The control tank held seawater at pH 8.2, reflecting current ocean levels, while the other tank contained more acidic water at pH 7.

Sebastian Fraune, the study’s senior author and professor at Heinrich Heine University, said that teeth exposed to more acidic water showed “visible surface damage such as cracks and holes, increased root corrosion, and structural degradation” compared with those incubated at pH 8.2.

The researchers noted that damage to shark teeth caused by acidified water could potentially affect how sharks capture and process their prey, which in turn might influence feeding efficiency and digestion.

The study examined only discarded, non-living shark teeth, so potential repair or replacement processes in living sharks were not considered.

The researchers noted that blacktip reef sharks swim with their mouths open, exposing teeth continuously to seawater, and even moderate drops in pH could cause damage, particularly in species with slower tooth replacement.

The study indicates that even microscopic damage could pose a significant threat to animals that rely on their teeth for survival.

“It’s a reminder that climate change impacts cascade through entire food webs and ecosystems,” Baum added.

Earlier it was reported that Australia’s Great Barrier Reef suffered worst coral decline on record.

Locked beneath a single-plate crust, Mars’ mantle holds a frozen record of the red planet’s primordial past, according to a new study of Martian seismic data collected by NASA’s InSight mission. The findings reveal a highly heterogenous and disordered mantle, born from ancient impacts and chaotic convection in the planet’s early history. “Whereas Earth’s early geological records remain elusive, the identification of preserved ancient mantle heterogeneity on Mars offers an unprecedented window into the geological history and thermochemical evolution of a terrestrial planet under a stagnant lid, the prevalent tectonic regime in our Solar System,” write the authors. “This evolution holds key implications for understanding the preconditions for habitability of rocky bodies across our Solar System and beyond.” A planet’s mantle – the vast layer that lies sandwiched between its crust and core – preserves crucial evidence about planetary origin and evolution. Unlike Earth, where active plate tectonics continually stirs the mantle, Mars is a smaller planet with a single-plate surface. As such, Mars’ mantle undergoes far less mixing, meaning it may preserve a record of the planet’s early internal history, which could offer valuable insights into how rocky worlds form and evolve. Using data from NASA’s InSight lander, Constantinos Charalambous and colleagues studied the seismic signatures of marsquakes to better constrain the nature of Mars’ mantle. By analyzing eight well-recorded quakes, including those triggered by meteorite impacts, Charalambous et al. discovered that high-frequency P-wave arrivals were systematically delayed as they traversed the deeper portions of the mantle. According to the authors, these delays reveal subtle, kilometer-scale compositional variations within the planet’s mantle. Because Mars lacks plate tectonics and large-scale recycling, these small-scale irregularities must instead be remnants of its earliest history. The scaling of Mars’ mantle heterogeneity suggests an origin in highly energetic and disruptive processes, including massive impacts early in the planet’s history, which fractured the planet’s interior, mixing both foreign and crustal materials into the mantle at a planetary scale. Moreover, the crystallization of vast magma oceans generated in the aftermath likely introduced additional variations. Instead of being erased, these features became frozen in place as Mars’ crust cooled and mantle convection stalled.

Rocky material that impacted Mars lies scattered in giant lumps throughout the planet’s mantle, offering clues about Mars’ interior and its ancient past.

What appear to be fragments from the aftermath of massive impacts on Mars that occurred 4.5 billion years ago have been detected deep below the planet’s surface. The discovery was made thanks to NASA’s now-retired InSight lander, which recorded the findings before the mission’s end in 2022. The ancient impacts released enough energy to melt continent-size swaths of the early crust and mantle into vast magma oceans, simultaneously injecting the impactor fragments and Martian debris deep into the planet’s interior.

There’s no way to tell exactly what struck Mars: The early solar system was filled with a range of different rocky objects that could have done so, including some so large they were effectively protoplanets. The remains of these impacts still exist in the form of lumps that are as large as 2.5 miles (4 kilometers) across and scattered throughout the Martian mantle. They offer a record preserved only on worlds like Mars, whose lack of tectonic plates has kept its interior from being churned up the way Earth’s is through a process known as convection.

The finding was reported Thursday, Aug. 28, in a study published by the journal Science.

“We’ve never seen the inside of a planet in such fine detail and clarity before,” said the paper’s lead author, Constantinos Charalambous of Imperial College London. “What we’re seeing is a mantle studded with ancient fragments. Their survival to this day tells us Mars’ mantle has evolved sluggishly over billions of years. On Earth, features like these may well have been largely erased.”

InSight, which was managed by NASA’s Jet Propulsion Laboratory in Southern California, placed the first seismometer on Mars’ surface in 2018. The extremely sensitive instrument recorded 1,319 marsquakes before the lander’s end of mission in 2022.

Quakes produce seismic waves that change as they pass through different kinds of material, providing scientists a way to study the interior of a planetary body. To date, the InSight team has measured the size, depth, and composition of Mars’ crust, mantle, and core. This latest discovery regarding the mantle’s composition suggests how much is still waiting to be discovered within InSight’s data.

“We knew Mars was a time capsule bearing records of its early formation, but we didn’t anticipate just how clearly we’d be able to see with InSight,” said Tom Pike of Imperial College London, coauthor of the paper.

Mars lacks the tectonic plates that produce the temblors many people in seismically active areas are familiar with. But there are two other types of quakes on Earth that also occur on Mars: those caused by rocks cracking under heat and pressure, and those caused by meteoroid impacts.

Of the two types, meteoroid impacts on Mars produce high-frequency seismic waves that travel from the crust deep into the planet’s mantle, according to a paper published earlier this year in Geophysical Research Letters. Located beneath the planet’s crust, the Martian mantle can be as much as 960 miles (1,550 kilometers) thick and is made of solid rock that can reach temperatures as high as 2,732 degrees Fahrenheit (1,500 degrees Celsius).

The new Science paper identifies eight marsquakes whose seismic waves contained strong, high-frequency energy that reached deep into the mantle, where their seismic waves were distinctly altered.

“When we first saw this in our quake data, we thought the slowdowns were happening in the Martian crust,” Pike said. “But then we noticed that the farther seismic waves travel through the mantle, the more these high-frequency signals were being delayed.”

Using planetwide computer simulations, the team saw that the slowing down and scrambling happened only when the signals passed through small, localized regions within the mantle. They also determined that these regions appear to be lumps of material with a different composition than the surrounding mantle.

With one riddle solved, the team focused on another: how those lumps got there.

Turning back the clock, they concluded that the lumps likely arrived as giant asteroids or other rocky material that struck Mars during the early solar system, generating those oceans of magma as they drove deep into the mantle, bringing with them fragments of crust and mantle.

Charalambous likens the pattern to shattered glass — a few large shards with many smaller fragments. The pattern is consistent with a large release of energy that scattered many fragments of material throughout the mantle. It also fits well with current thinking that in the early solar system, asteroids and other planetary bodies regularly bombarded the young planets.

On Earth, the crust and uppermost mantle is continuously recycled by plate tectonics pushing a plate’s edge into the hot interior, where, through convection, hotter, less-dense material rises and cooler, denser material sinks. Mars, by contrast, lacks tectonic plates, and its interior circulates far more sluggishly. The fact that such fine structures are still visible today, Charalambous said, “tells us Mars hasn’t undergone the vigorous churning that would have smoothed out these lumps.”

And in that way, Mars could point to what may be lurking beneath the surface of other rocky planets that lack plate tectonics, including Venus and Mercury.

JPL managed InSight for NASA’s Science Mission Directorate. InSight was part of NASA’s Discovery Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supported spacecraft operations for the mission.

A number of European partners, including France’s Centre National d’Études Spatiales (CNES) and the German Aerospace Center (DLR), supported the InSight mission. CNES provided the Seismic Experiment for Interior Structure (SEIS) instrument to NASA, with the principal investigator at IPGP (Institut de Physique du Globe de Paris). Significant contributions for SEIS came from IPGP; the Max Planck Institute for Solar System Research (MPS) in Germany; the Swiss Federal Institute of Technology (ETH Zurich) in Switzerland; Imperial College London and Oxford University in the United Kingdom; and JPL. DLR provided the Heat Flow and Physical Properties Package (HP³) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain’s Centro de Astrobiología (CAB) supplied the temperature and wind sensors.

Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov

Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov

2025-110