The Moon’s far side is overturning a long-held theory, revealing that the early Solar System’s asteroid assault may have faded slowly instead of exploding in one catastrophic burst. For decades, scientists have debated whether the early Solar System endured one sudden, catastrophic wave of asteroid strikes or a much longer period of gradually fading violence. [...]
Scientists once suspected that a brutal, years-long winter starved the dinosaurs following an asteroid impact 66 million years ago. New evidence suggests a more violent end: widespread firestorms that may have burned even thick-skinned dinosaurs to a crisp within hours.
The roughly six-mile-wide (10-kilometer-wide) asteroid struck Mexico's Yucatán Peninsula, excavating the Chicxulub crater and vaporizing enormous quantities of rock. Some of that material condensed into tiny droplets called spherules, which spread around the planet before falling back through Earth's atmosphere at several miles per second.
As the spherules slowed, their kinetic energy became heat, producing an intense pulse of thermal radiation. Earlier models suggested the effect would have resembled a worldwide broiler that was potentially deadly to exposed, thin-skinned animals, but not powerful enough to ignite vegetation across the globe.
A new study argues that those calculations overlooked a crucial ingredient: a thick layer of fine silicate dust formed from rock vapor that did not initially condense into spherules. Evidence for that dust emerged in 2023 from the Tanis fossil site in North Dakota, where researchers identified a layer of extremely fine, impact-derived material deposited above the spherules. A similar dust layer has since been documented at the K–Pg boundary (which divides the "age of reptiles" and the "age of mammals") in Raton Basin across the Colorado–New Mexico border.
"It reinvigorated my interest in what happened to the leftover vapor — that's where this work started," lead author Brandon Johnson, a planetary scientist at Purdue University, said in a statement.
The dust would have acted like an insulating blanket, preventing thermal radiation from escaping into space and redirecting more heat toward Earth’s surface. The researchers estimated that the surface heat pulse could have been about 3.5 times more intense than what was suggested by models considering the falling spherules alone. "We're in the realm where we might be essentially killing off everything within that first hour or two," Johnson said.
The radiation may not have directly ignited thick pieces of wood, but it exceeded ignition thresholds for grass, lichen, and pine needles, which could have fueled larger fires. The study also found that exposed terrestrial animals may have received about 17 times the thermal dose considered lethal to humans.
Animals sheltering underground or in water would have had a better chance of surviving the initial heat pulse. Afterward, the same dust may have blocked sunlight for years, triggering the prolonged "impact winter" more typically blamed for the dinosaurs' extinction.
There is, however, a missing element: the wildfire evidence that supports this dust-caused inferno theory has only been found in North America. "It could be that we will eventually find the record of completely global wildfires," said Alfio Alessandro Chiarenza, a paleontologist at University College London who was not involved in the study. "We just don't have it so far."
The study was published on July 28 in the journal JGR Biogeosciences.
A solar eclipse, the Perseids, bright Venus after sunset, and a deep partial lunar eclipse highlight August’s skywatching.
A solar eclipse, one of the year’s best meteor showers, Venus at its brightest in the evening sky, and a lunar eclipse to close out the month.
That’s “What’s Up” for August.
On Aug. 12, a total solar eclipse crosses northern Russia, Greenland, Iceland, and northern Spain, with a small corner of Portugal inside the path of totality.
In parts of the United States, from Alaska to North Carolina, the eclipse is partial. The Moon will take only a small bite out of the Sun, and the amount of coverage will vary with location.
Remember to watch safely. Use certified eclipse glasses or a safe solar viewer any time any part of the Sun is visible. Regular sunglasses are not safe. And never use binoculars, a telescope, or a camera without a solar filter made for the front of the optics.
Later that same night, the Perseid meteor shower will light up the sky, peaking the evening of Aug. 12 into the early morning hours of the 13th. And with a New Moon arriving on the 12th, the skies will be ideally dark.
The Perseids happen every year when Earth passes through a debris stream left behind by Comet Swift-Tuttle. As those tiny bits of comet dust hit our atmosphere at high speed, they burn up as bright streaks of light.
To view this meteor shower, look toward the northeast once it’s fully dark and watch for the constellation Perseus to clear the horizon. This is where the meteors originate, but let your eyes wander, because they can flash across any part of the sky.
For the best view, stay out late as the stars climb higher, find a dark open spot, and give your eyes 30 minutes to adjust.
Aug. 14-16, Venus reaches its greatest eastern elongation, which is its widest apparent separation from the Sun during this evening appearance.
Look low in the western sky shortly after sunset for the bright object that will outshine every star around it. Through a telescope after sunset, Venus will look close to half lit, like a tiny lunar phase.
On the night of Aug. 27, continuing into Aug. 28 for some time zones, the Full Moon slips through Earth’s shadow, resulting in a partial lunar eclipse. It will be visible from much of North and South America and parts of Europe and Africa.
At maximum eclipse, about 93% of the Moon’s diameter will be inside Earth’s dark central shadow, called the umbra. The Moon will not be completely covered, but it can look dramatically darkened, with a rusty, coppery tint along the covered edge.
Unlike a solar eclipse, a lunar eclipse is safe to watch with just your eyes. Binoculars or a small telescope can give you a closer view of Earth’s curved shadow moving across the Moon.
Here are the phases of the Moon for August.
You can stay up to date on all of NASA’s missions exploring the solar system and beyond at science.nasa.gov. I’m Raquel Villanueva from NASA’s Jet Propulsion Laboratory, and that’s What’s Up for this month.
The post What’s Up: August 2026 Skywatching Tips from NASA appeared first on NASA Science.
A solar eclipse, the Perseids, bright Venus after sunset, and a deep partial lunar eclipse highlight August’s skywatching.
A solar eclipse, one of the year’s best meteor showers, Venus at its brightest in the evening sky, and a lunar eclipse to close out the month.
That’s “What’s Up” for August.
On Aug. 12, a total solar eclipse crosses northern Russia, Greenland, Iceland, and northern Spain, with a small corner of Portugal inside the path of totality.
In parts of the United States, from Alaska to North Carolina, the eclipse is partial. The Moon will take only a small bite out of the Sun, and the amount of coverage will vary with location.
Remember to watch safely. Use certified eclipse glasses or a safe solar viewer any time any part of the Sun is visible. Regular sunglasses are not safe. And never use binoculars, a telescope, or a camera without a solar filter made for the front of the optics.
Later that same night, the Perseid meteor shower will light up the sky, peaking the evening of Aug. 12 into the early morning hours of the 13th. And with a New Moon arriving on the 12th, the skies will be ideally dark.
The Perseids happen every year when Earth passes through a debris stream left behind by Comet Swift-Tuttle. As those tiny bits of comet dust hit our atmosphere at high speed, they burn up as bright streaks of light.
To view this meteor shower, look toward the northeast once it’s fully dark and watch for the constellation Perseus to clear the horizon. This is where the meteors originate, but let your eyes wander, because they can flash across any part of the sky.
For the best view, stay out late as the stars climb higher, find a dark open spot, and give your eyes 30 minutes to adjust.
Aug. 14-16, Venus reaches its greatest eastern elongation, which is its widest apparent separation from the Sun during this evening appearance.
Look low in the western sky shortly after sunset for the bright object that will outshine every star around it. Through a telescope after sunset, Venus will look close to half lit, like a tiny lunar phase.
On the night of Aug. 27, continuing into Aug. 28 for some time zones, the Full Moon slips through Earth’s shadow, resulting in a partial lunar eclipse. It will be visible from much of North and South America and parts of Europe and Africa.
At maximum eclipse, about 93% of the Moon’s diameter will be inside Earth’s dark central shadow, called the umbra. The Moon will not be completely covered, but it can look dramatically darkened, with a rusty, coppery tint along the covered edge.
Unlike a solar eclipse, a lunar eclipse is safe to watch with just your eyes. Binoculars or a small telescope can give you a closer view of Earth’s curved shadow moving across the Moon.
Here are the phases of the Moon for August.
You can stay up to date on all of NASA’s missions exploring the solar system and beyond at science.nasa.gov. I’m Raquel Villanueva from NASA’s Jet Propulsion Laboratory, and that’s What’s Up for this month.
Asteroid 44 Nysa has the weirdest shape yet seen for an asteroid, and that’s saying something.
The post Astronomers Spot Weird, Three-Lobed Asteroid with a Moon appeared first on Sky & Telescope.
Traversing through the solar system, a comet split in two, and a recent study used six months of observations to investigate when and why.
Orbital path of 240P/NEAT (purple) and the position of the comet on 30 July 2026 (light blue teardrop). Click to enlarge. [TheSkyLive]
Most recently, 240P swept closest to Jupiter in July 2007, shifting the comet’s perihelion distance (closest approach to the Sun) from 2.5 to 2.1 au, and several long-lived bursts in brightness in 2018/2019 could have been spurred by this orbital shift. Excitingly, a fainter comoving object, 240P-B, was first reported in June 2025 as the comet headed toward perihelion — at some point recently, 240P had split in two!
Over the last century, numerous split comets have been recorded, but detailed physical studies of these objects are rare. With growing evidence suggesting splitting and disintegration are the primary mechanisms of comet destruction, understanding the properties and cause of 240P’s split is imperative.
With 240P on the move to perihelion, David Jewitt (University of California, Los Angeles) and collaborators monitored the comet from October 2025 to April 2026 to establish the likely cause of its split. Employing the Alhambra Faint Object Spectrograph and Camera on the 2.56-meter Nordic Optical Telescope, the authors obtained detailed imaging of the comet from two months before to four months after perihelion to characterize both components.
Tracking both photometric and morphological changes across their observations, the authors estimated the dust-loss rates, physical sizes, and separation speed of 240P-A and 240P-B. The brighter component, 240P-A, has an estimated radius between 400 and 600 meters and a dust-loss rate almost four times higher than 240P-B. Because 240P-B is fainter, its radius is harder to constrain observationally. From its lower dust-loss rate and lower brightness, the authors estimated a radius around 300 meters (and no smaller than 50). Based on how the separation of the two comet pieces changes over time, the authors determined that the split of 240P occurred at least three years before their observations.
Dust mass-loss rates for 240P-A (green circles) and 240P-B (yellow diamonds) over the course of the observations. Both components peak shortly before perihelion (dashed vertical line). Click to enlarge. [Jewitt et al 2026]
How exactly did this fragmented comet get this way? The authors considered a number of comet-splitting mechanisms: tidal forces, asteroid impact, pressure buildup below the comet’s surface, thermal stresses, and rotational instability. Given the comet’s orbit, it has not had close enough encounters with the Sun or other planets for tidal forces to be the culprit, and it traverses well above the asteroid belt, avoiding collisions. Pressure buildup and thermal stresses can fracture comets, but both are unlikely to launch such a large fragment as seen in this system.
This leaves rotational instability as the likely source of 240P’s split. Outgassing torques lead to rotational instability, especially in subkilometer comets like 240P, and 240P has exhibited recent outgassing. In addition, the separation speed between the 240P components is comparable to the escape speed of the primary comet, which is expected for rotational breakup. To confirm this hypothesis, future observations measuring the rotation period of 240P are necessary, but this study adds to the small number of split-comet observations that aid in understanding comet destruction.
“Investigation of Split Comet 240P/NEAT,” David Jewitt et al AJ 172 113. doi:10.3847/1538-3881/ae83ac
The post Spying on a Split Comet appeared first on AAS Nova.
Scientists have found the first triple-lobed asteroid in the asteroid belt between Mars and Jupiter — and it has a small moon to boot.
The asteroid in question is 44 Nysa, which was discovered all the way back in 1857. Of course, back then it was just a pinprick of light in the sky, and subsequent observations — including some from the Hubble Space Telescope — had failed to tell us much about Nysa. Those previous observations suggested Nysa might be bi-lobed, like many asteroids and comets such as asteroid 52246 Donaldjohanson, which NASA's Lucy mission flew past in 2025.
However, new joint observations by the Large Binocular Telescope (LBT) on Mount Graham in Arizona and the Very Large Telescope (VT) on Paranal mountain in Chile have revealed that this asteroid actually seems to have three lobes, the first such object ever seen.
"The images reveal a remarkably unusual object," said lead researcher Kate Minker of Arizona's Lowell Observatory in a statement. "The most likely explanation is that Nysa is either a contact trinary, consisting of three connected components, or an extremely irregular coherent body unlike anything we've previously observed."
Obtaining the detailed images of Nysa was not easy. Key to the success were two high contrast imaging devices, the Italian-built SHARK-VIS on the LBT and SPHERE and its ZIMPOL polarimeter on the VLT, used in conjunction with adaptive optics that counteract the blurring effect of the atmosphere.
"These observations had to be combined with specially developed image-processing techniques to further sharpen the images and remove the bright halo surrounding the asteroid, potentially hiding faint companions," said Anthony Berdeu of the European Southern Observatory.
The images showed an irregular-shaped body 47 miles (75 kilometers) at its widest point, with two notable valleys or "colli" that wrap around the asteroid's circumference and which Minker's team interprets as being the necks of the different lobes. Furthermore, the images revealed a 0.6-mile-wide (1-km-wide) moon orbiting Nysa at a distance of at least 106 miles (170 km). The moon has been designated S/2026 (44) 1 for now. And, because it was seen independently during two different observing campaigns, it was possible to observe its motion around Nysa.
"We borrowed a specialized technique from another field of astronomy, known as high-contrast imaging, to detect the small moon whose faint light was overwhelmed by the intense brightness of the primary asteroid," said Gianluca Li Causi of the SHARK-VIS team at the Italian National Institute for Astrophysics (INAF).
Nysa is named after the mythical land where the ancient Greek god Dionysus was raised by nymphs. Al Conrad of the Large Binocular Telescope Observatory finds the name fitting because Dionysus was the Greek god of theater, which for the ancient Greeks often involved wearing masks and hiding one's true identity.
"We're finally unmasking the asteroid's true nature, long after it was discovered," said Conrad.
How such a bizarre object formed remains uncertain, but Minker's team does have a couple of ideas.
The team's preferred explanation is that Nysa is a contact trinary — three asteroid bodies being held together loosely by gravity. The best alternative, the researchers say, is that Nysa once upon a time had a close encounter with a much larger asteroid that slammed into it, thereby deforming it. In these situations, modeling suggests that gravitational tidal forces could have deformed Nysa's mantle, creating Nysa's odd shape and even ripping it apart into a bunch of fragments in a string-of-peals configuration. If this is the case, then where did the other fragments go? Such events usually produce a family of asteroids all sharing the same composition, but Nysa seems to be alone (barring its moon, of course).
There could be a way to distinguish between the two possible origins. By tracking the moon's orbital velocity and period, astronomers will be able to pin down the exact mass and density of Nysa and then see which model matches it best.
Nysa has been a subject of study because it can also tell us about the birth of our own planet Earth. Nysa is more reflective than many other asteroids thanks to its surface composition that is abundant in a silicate mineral called enstatite, which lacks iron. Asteroids like this are generally called E-types, and Nysa is the largest and brightest of all of them. E-type asteroids are thought to have formed close to the sun and therefore have been identified as potential building blocks of the inner planets. If Nysa is a relic of that time, it could tell us a great deal about conditions in the inner solar system 4.5 billion years ago.
The findings can be read on the arXiv archive, and have been submitted to the journal Astronomy & Astrophysics.
The diets of penguins on Antarctica's Danger Islands can be seen from space. At least indirectly.
Using satellite images captured by the Landsat 8 spacecraft operated by NASA and the United States Geological Survey, scientists can track changes in Adélie penguins' diets based on the color of their guano, or droppings.
The image above shows pinkish-orange guano staining large sections of some of the Danger Islands, Heroína Island and Beagle Island. The penguins that live there eat a diet rich in krill, small marine crustaceans that are bright pink in color due to a specific type of algae upon which they feed.
The bright pink color of the penguins' droppings stands out in satellite imagery, allowing researchers to monitor the birds' populations from space. But scientists wanted a closer look, and collected drone imagery as well, as seen in the image below.
It's pretty amazing that the diet of a specific population of birds can be monitored from 438 miles (705 kilometers) above Earth's surface. The imagery collected by Landsat-8 helped scientists locate where the penguin colonies might be, allowing them to find them in-person and collect guano samples. Those samples contained evidence of what the penguins were eating over time.
Researchers are using those satellite images and samples to track how the penguins' diet might be affected by changes in sea ice conditions, according to a NASA statement.
"Sea ice is such a hugely important factor in the Antarctic marine environment," said Clemson University biologist Casey Youngflesh who led a study comparing the penguins' diet and sea ice conditions. "The structure of the region's food web is changing in response."
On Aug. 5, Earth's moon is due for a human-made, high-speed impact from an identified flying object: a spent SpaceX Falcon 9 upper stage. The event will lead to a literal "dust up" on the lunar landscape.
That Falcon 9 upper stage is a leftover from the launch that sent Firefly's Blue Ghost-1 lander to the moon on Jan. 15, 2025. Onboard the same flight was the Hakuto-R Mission 2, called Resilience, a robotic lunar lander developed by the Japanese company ispace.
And according to a new study by an international team published on the open-source arXiv server, the resulting impact plume may briefly be bright enough to see against the dark sky near the moon's edge. That means it might be visible to moongazers with sufficiently sensitive telescopes.
This head-on collision of the errant stage is expected to occur near the Einstein and Bell craters near the western lunar limb. It may well be visible to ground and space-based assets. Indeed, putting aside all the unknowns and modeling uncertainties, some specialists suggest if you've got the time and observational prowess, it might be worth a look.
Using special physics simulations to model the impact, William Jo, a graduate research assistant at the University of Texas, Austin and colleagues predict the debris plume from the impact will have the central ejecta spike reaching roughly 47 miles to over 60 miles (75 kilometers to 100 kilometers) altitude.
"Our calculations suggest the plume should be several orders of magnitude brighter than the dark-sky background for the first few minutes after impact," Jo told Space.com. "So the plume should be visible, though I'd stress this is a single nominal case. The real one will look different, and the numbers are on the optimistic side. But the point worth making is that the flash isn't really the story here."
Jo emphasized that there's great slam-dunk science to be had. "Watching this one gives us a rare chance to open up ejecta-plume science and calibrate those models against a real event, which matters for every future thing we deliver to the moon," Jo said.
According to new research led by Benjamin Fernando of the Los Alamos National Laboratory in New Mexico, the impact flash and resultant ejecta plume are "potentially observable" from ground- and space-based observational facilities.
"This event provides an opportunity to attempt the recording of an artificial impact in real-time; although many of the properties of the event (such as visual magnitude) are imprecisely predicted at present," Fernando and colleagues report.
Moreover, this rocket stage meets moon occasion yields an opportunity to test a pipeline for localizing impacts on the lunar surface for future seismic experiments, investigating the dust and plume dynamics from impact events on the moon, and considering hazards from artificial space debris impacts that future astronauts on the lunar surface might have to avoid, Fernando and team members point out.
"The maximum ballistic range of resolved particles is found to be slightly under 1,000 km, which is far enough to be significant from the perspective of presenting a hazard to future astronauts or infrastructure across much of the lunar surface," Fernando et al wrote in the study.
Brent Garry is a project scientist for NASA's Lunar Reconnaissance Orbiter (LRO) at Goddard Space Flight Center in Greenbelt, Maryland. LRO will be passing over the projected rocket stage crash site about seven days prior to the impact and about seven days after the impact, Garry explains.
"After the impact we might have a little bit more knowledge of where it is. We can do some additional targeting about a week after the impact and get some targeting over where the site is," said Garry, as noted in earlier Space.com reporting.
Meanwhile, Jo at the University of Texas, Austin underscores the fact that a spent rocket stage is a hollow, spacecraft-like body, and there are very few impact models for human-made objects like it. They seem to produce very different plumes than natural impactors, like asteroids or comets do. But Jo stresses that the real scientific contributions will come by studying the moments after the impact.
"My concern is that most observers will stop at the sub-second flash and never track down the ejecta, which is the part that should actually be visible, and where the science is."
A new look at more than two decades’ worth of archival data from NASA’s Spirit mission suggests that the Martian soil may hold iron-bearing minerals -- hematite and altered magnetite -- that were too faint for scientists to detect in real time during the mission.
The post Hidden Clues in Spirit Rover Data Suggest Mars Once Had Far More Water than Scientists Realized appeared first on Sci.News: Breaking Science News.
Ash from countless volcanic eruptions on Io have likely built up its porous surface.
The post Jupiter’s Moon Io is Surprisingly Fluffy appeared first on Sky & Telescope.
Europa’s subsurface ocean has long topped astrobiologists’ wish lists as a place to search for life beyond Earth.
The post Europa’s Ice Shell May Be Tougher Barrier than Planetary Scientists Hoped appeared first on Sci.News: Breaking Science News.
The small exoplanets of our Sun’s second-nearest neighbor, Barnard’s Star, are inhospitable wastelands, British astronomers say.
Located six light-years from Earth, Barnard’s Star is separated from our closest neighbor, Alpha Centauri, by about 66° in our sky. Now, University of Cambridge researchers have revealed their findings on this exosolar system in a recent paper published in the Monthly Notices of the Royal Astronomical Society.
After careful analysis, the astronomers announced that the exoplanets are unlike any in our solar system, presenting a brutal and barren environment.
Scientists only discovered these four small planets orbiting Barnard’s Star in 2025. Unlike anything in our solar system, these orbital bodies fit into a size range larger than Mars, but smaller than Earth or Venus.
Like a peeled onion, these smaller planets are rich in a mineral only found deep below the Earth’s surface. Chemical analysis revealed large amounts of the mineral periclase on the surface of these planets, something typically only found hundreds of kilometers deep on our planet.
“Barnard’s Star has an enormous amount of the element magnesium compared to other stars, so its planets are likely to be rich in magnesium too,” said lead author Xander Byrne from Cambridge’s Institute of Astronomy. “On Earth, that magnesium goes into making minerals called olivines, which are really important for storing water within the planet.”
Unfortunately for those looking for extraterrestrial life, magnesium serves a different purpose on these exoplanets. Instead of water-storing olivine, it produces the abundant periclase, which is a poor store of water.
Even worse, these inhospitable exoplanets likely no longer have an atmosphere. According to the University of Cambridge team, these ten-billion-year-old planets probably only managed to hold an atmosphere for two billion years at most.
“These planets were always going to be hostile, because they’re really close to their star,” said Byrne. “Even the outermost planet orbits ten times closer than Mercury orbits the Sun. When you’re that close to your star, and have such little gravity, your atmosphere just gets blown off.”
In addition to the lack of atmosphere, the planets’ proximity to Barnard’s Star leaves them tidally locked, like our Moon, with one side always facing toward the star.
However, there is one positive element to these small planets. Typically, such close-orbiting systems are highly unstable, with the planets shooting out from the system, falling into their host star, or catastrophically colliding. Yet in this case, the system is as ordered as a piece of music.
The three inner planets of the exosolar system have years in a 9:12:16 ratio, producing two of what is known as a “perfect fourth” in music. This musical harmony is known as an orbital resonance, with the same type of effect stabilizing Jupiter’s moons in their orbits around that planet.
While our ability to view Barnard’s Star from Earth may be limited, the European Space Agency’s upcoming Plato mission may allow astronomers to discover ever smaller worlds orbiting in the nearby exosolar system.
“Larger planets are much easier to detect than small ones, so we know about very few sub-Earth planets like the ones in this system,” said Byrne. “But the sensitivity of these new missions will help to reduce this bias, allowing us to discover more and more planets that are small and rocky, like Earth.”
The true significance of the research may lie in the value of a null result. While these planets are bleakly hostile to life, observing this exosolar system’s composition can aid future astronomers in narrowing down the search for extraterrestrial life.
The paper, “The Barnard’s Star Planetary System: Stability, Composition, and Evolution of Four Sub-Earth Exoplanets,” appeared in Monthly Notices of the Royal Astronomical Society on June 24, 2026.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.
Born on July 25, 1920, Chushiro Hayashi graduated from the University of Tokyo with a degree in physics in 1942. After World War II service in the navy, he returned to school, finishing his doctorate in 1954 and becoming a professor at Kyoto University in 1957. An innovator, he applied fundamental physics to astronomy andContinue reading "July 25, 1920: The birth of Chushiro Hayashi"
The post July 25, 1920: The birth of Chushiro Hayashi appeared first on Astronomy Magazine.
New 3D computer simulations from ETH Zurich show that young rift flanks on Venus stay tall and steep, while older ones flatten out over time.
The post Giant Rift Valleys Hint Venus is Still Tectonically Active appeared first on Sci.News: Breaking Science News.
Scientists have measured temperatures beneath the surface of Jupiter's volcanic moon Io, offering the first-ever glimpse of the hidden heat driving the most volcanically active world in the solar system.
During close flybys of Io in late 2023 and early 2024, NASA's Juno spacecraft turned its Microwave Radiometer (MWR) instrument toward the moon, probing roughly six to 20 feet (two to six meters) beneath its surface. Originally designed to peer through Jupiter's thick clouds, the instrument instead revealed a powerful new way to study how heat moves through planetary crusts, according to a statement from the space agency.
"The surprising discovery that we could see below a rocky moon's surface has important implications for studying Earth's volcanoes," Scott Bolton, coauthor of the study and Juno's principal investigator, said in the statement. "Juno has taught us that if we look with an MWR-type instrument near a volcano on Earth, we might see a similar signature in the subsurface temperature gradient, providing new information on how terrestrial volcanoes work."
Until now, researchers had relied almost entirely on infrared observations, which detect only the temperature of Io's surface. By probing several feet underground, Juno has revealed how heat moves through the moon's crust for the first time.
The measurements showed temperatures rising by more than 40 degrees Fahrenheit (22 degrees Celsius) just a few feet below the surface — far more than sunlight alone could explain. Juno's subsurface heat map also revealed localized regions of elevated heat, with temperatures measuring between 18 and 36 degrees F (10 to 20 degrees C) warmer than the surrounding terrain, according to the statement.
Juno's observations uncovered another surprise, too. Despite being known for its towering mountains and active volcanoes, much of Io's surface appears remarkably smooth and composed of unusually low-density material. Researchers think the moon is blanketed by porous layers of volcanic ash, sulfur frost and other eruptive debris that continually resurface Io, burying older terrain beneath fresh deposits.
Scientists think the heat detected beneath Io's surface could be rising steadily from the moon's molten interior through a conductive crust or coming from pockets of cooling lava flows trapped just below the surface. Either way, the data provide the clearest picture yet of how Io transports heat from its interior.
Unlike Earth, where volcanism is driven largely by heat from radioactive decay, Io is continuously stretched and squeezed by Jupiter's immense gravity as it orbits the giant planet. This constant tidal flexing generates enormous amounts of internal heat, fueling hundreds of active volcanoes and making Io the most volcanically active object in the solar system. By improving scientists' understanding of how heat and magma move beneath a planet's surface before eruptions, the same microwave techniques used by Juno could one day help researchers better monitor Earth's volcanoes and improve eruption forecasting.
"Io provides a unique window into learning how tidal heating works throughout the cosmos, a fundamental process that provides energy and heat to worlds that are far from their parent star," Bolton said in the statement. "This process can not only create the most volcanic body in the solar system, in the case of Io, but also fuels the subsurface oceans on the moons of giant planets, such as Europa and Ganymede. Up until this point we could only observe the heat escaping at the surface or through eruptions. Now we can characterize how the heat is moving from the interior toward the surface."
Because Io is an extreme example of volcanic activity, it serves as a natural laboratory for studying how heat moves through planetary crusts. Those insights could help scientists better understand ancient volcanism on Mars, Venus, and Earth's moon, whose landscapes were shaped by massive eruptions billions of years ago.
The technique could also aid the search for life elsewhere. While Io itself is far too hostile to support life, microwave instruments can also probe beneath icy surfaces. Juno has already used the same instrument to study Jupiter's moons Europa and Ganymede, where scientists believe vast oceans lie hidden beneath thick shells of ice. Understanding how heat moves through those crusts is key to determining whether they could harbor environments suitable for life as we know it.
Their findings were published July 22 in the Journal of Geophysical Research: Planets.
When NASA’s OSIRIS-REx spacecraft delivered pristine samples from the asteroid Bennu back to Earth in 2023, scientists knew they were receiving one of the most chemically untouched collections of material ever recovered from the Solar System.
Since then, the returned grains have steadily transformed researchers’ understanding of how asteroids formed, how water altered primitive worlds, and even how the ingredients for life may have spread through the early Solar System.
Now, a new study, published in Nature Communications, has uncovered another surprise hidden inside those microscopic particles. Embedded within Bennu are tiny mineral fragments that formed during the Solar System’s earliest moments—less than 100,000 years after its birth—and they may reveal that the asteroid’s ancient parent body formed much farther from the Sun than scientists once suspected.
The research suggests that Bennu inherited some of the oldest surviving solids ever created, while simultaneously preserving evidence that Jupiter’s formation may have acted as an enormous cosmic filter, separating different populations of dust before planets had even fully formed.
“Our observations of phyllosilicates replacing olivine and interstitial phyllosilicates between olivine grains within AOAs… collectively indicate that these refractory inclusions experienced aqueous alteration on Bennu’s parent planetesimal,” researchers write. “Therefore, they were incorporated into the parent planetesimal before the onset of aqueous alteration, during which phyllosilicates and magnetite formed.”
“These mineralogical, isotopic, and chronological similarities among refractory inclusions in Bennu samples, Ryugu samples, and CI chondrites provide evidence that their parent planetesimal(s) accreted a common suite, and likely similar relative abundances, of high-temperature refractory inclusions and their fragments,” researchers write.
The research concentrates on “refractory inclusions”—tiny mineral-rich objects known as calcium-aluminum-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs). These objects are widely considered the oldest solid materials to condense from the hot gas surrounding the newborn Sun.
Long before planets existed, the infant Solar System consisted of a rotating disk of gas coupled with dust known as the protoplanetary disk. Temperatures near the young Sun exceeded 2,000 degrees Fahrenheit (roughly 1,100 degrees Celsius), allowing only the most heat-resistant minerals to crystallize.
These refractory inclusions were among the very first solids to emerge from that environment before eventually being transported throughout the growing Solar System.
Although scientists have found such inclusions in meteorites for decades, Bennu offered an unprecedented opportunity to examine them in material collected directly from an asteroid rather than from meteorites that survived passage through Earth’s atmosphere.
To investigate, researchers analyzed polished sections prepared from 12 Bennu particles using scanning electron microscopy, transmission electron microscopy, oxygen isotope measurements, and radioactive aluminum-magnesium dating techniques.
The team identified six amoeboid olivine aggregates and three calcium-aluminum-rich inclusions, all remarkably small—none exceeding roughly 100 micrometers across, or about the thickness of a human hair. This turned out to be one of the study’s most important discoveries.
The mineral chemistry and oxygen isotopes showed these inclusions formed in an extremely hot, oxygen-16-rich environment during the Solar System’s earliest stages. Radioactive dating using aluminum-26 indicated at least one inclusion formed essentially at the very beginning of Solar System history, within roughly the first 100,000 years after the earliest known solids condensed.
In other words, Bennu contains fragments that have survived for approximately 4.567 billion years with surprisingly little alteration. Yet, those ancient relics also preserve evidence that they later encountered liquid water.
Several inclusions show minerals partially replaced by phyllosilicates—water-bearing clay minerals—while magnetite and other alteration products reveal that water once circulated through Bennu’s ancient parent body after these primordial objects had already become incorporated into it.
For scientists, that sequence helps establish a timeline. First, the earliest high-temperature solids formed close to the newborn Sun. Later, they were transported outward through the protoplanetary disk. Only after they became part of Bennu’s larger parent asteroid did liquid water alter portions of the rock.
Researchers found distinct similarities between Bennu’s inclusions and those previously identified in samples returned from Japan’s Hayabusa2 mission to asteroid Ryugu, as well as in rare CI carbonaceous chondrite meteorites found on Earth.
The oxygen isotopes, crystal chemistry, and formation ages all closely match, suggesting these seemingly distant objects inherited material from the same population of ancient Solar System building blocks.
That mutual heritage points toward a surprisingly interconnected early Solar System, where material formed close to the Sun was efficiently transported across enormous distances before eventually becoming incorporated into multiple asteroid populations.
However, the absence of something proved just as revealing as what scientists found.
Unlike many carbonaceous meteorites, Bennu contains no large refractory inclusions larger than about one-tenth of a millimeter. Other meteorites frequently preserve inclusions ranging from submillimeter sizes up to several centimeters across.
According to the researchers, the missing population may reflect the increasing influence of the Solar System’s first giant planet.
As proto-Jupiter accumulated mass, its gravity likely created a pressure bump within the gas disk encircling the young Sun. Such pressure bumps act as natural traffic jams for dust, trapping larger particles while allowing much smaller grains to continue drifting through the disk.
Under this scenario, larger refractory inclusions became concentrated closer to Jupiter’s orbit. At the same time, only the smallest particles were able to migrate farther outward into the distant regions where Bennu’s parent body eventually formed.
If correct, Bennu’s microscopic inclusions effectively record the influence of Jupiter before the giant planet had even fully matured.
The hypothesis also helps explain why Bennu, Ryugu, and CI meteorites all possess nearly identical populations of tiny refractory inclusions while lacking the larger varieties commonly found elsewhere.
Rather than showing different source materials, the distinction may instead reflect where—and perhaps when—their parent bodies assembled within the developing protoplanetary disk.
The findings similarly reinforce earlier studies suggesting Bennu is among the Solar System’s most chemically primitive objects. Because large refractory inclusions contain unusually high concentrations of certain elements, their absence helps preserve Bennu’s overall composition close to that of the earliest solar nebula from which the planets formed.
That makes the asteroid an unusually valuable time capsule. Every new microscopic grain examined inside the OSIRIS-REx collection provides another insight into processes that occurred billions of years before Earth existed as a habitable world.
Rather than simply representing rubble from a small asteroid, Bennu appears to preserve a remarkably faithful record of how the Solar System sorted, mixed, transported, and assembled its earliest building materials.
The study also demonstrates why sample-return missions have grown increasingly important to planetary science. Laboratory instruments on Earth can perform measurements impossible for spacecraft operating millions of miles away, letting researchers reconstruct events that occurred within the Solar System’s first fractions of a million years.
“We conclude that Bennu’s parent planetesimal, like those of Ryugu and CI chondrites, accreted small refractory inclusions that persisted in the outer Solar System beyond the influence of the proto-Jupiter-induced pressure bump,” researchers write. “Taken together, these findings highlight the need to integrate Bennu samples into comparative studies of early Solar System solids to better constrain the diversity and possible genetic links among planetesimal formation pathways,” researchers write.
The study, “Refractory inclusions in Bennu samples indicative of outer Solar System accretion,” appeared in Nature Communications.
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com
Scientists working at the European Southern Observatory’s Very Large Telescope (ESO’s VLT) in Chile have detected evidence for an unusual, ‘moon-like object’ in the CD-35 2722 system that doesn’t appear to orbit a planet.
The research team behind the discovery said the unusual object, which orbits a brown dwarf that orbits a large, Sun-like star, doesn’t fit normal astronomical categories, leaving them unsure what to name it.
If confirmed, the unusual space object would be the first moon without a host planet ever discovered. Such a confirmation would also make the newly termed “exosatellite” the first exomoon of any type discovered outside our Solar System.
According to a statement announcing the moon-like object, ESO student Kevin Hoy had been monitoring the CD-35 2722 star system for months. The measurements that spotted the new, moon-like object were taken with the observatory’s CRIRES+ instrument using the radial velocity method that spotted the first planet around a Sun-like star.
During that time, the researcher and lead author of a study detailing the find said he noticed the system was “super weird” compared to our local Solar System. While the star at the center of the system, with a mass of about half of our Sun, was not unusual, they also determined that it is orbited by a brown dwarf. Brown dwarfs are astronomical objects too small to be a star, but too massive to be a planet, making the pairing unusual. Still, it was not unheard of.
However, according to Hoy, when the team spotted a third, smaller object in the system, they were left confused. Measurements indicated it is at least as massive as Jupiter, suggesting it may be a moon orbiting the Brown Dwarf, only without a host planet.
“The satellite we report is a giant gaseous body orbiting a highly massive companion, itself several times the mass of Jupiter,” explained Alice Zurlo, Director of the Millennium Nucleus of Young Exoplanets and their Moons (YEMS) in Chile project and collaborator on the study.
The team has temporarily named the moon-like object an “exosatellite.” However, Hoy said the object’s status as a ‘third wheel’ in the system makes them want to classify it as a moon, “even if it is nothing like the small, rocky moons we have in our system.”
“This system is somewhat hard to define using Solar-System-based words like ‘planet’ and ‘moon’,” the researcher explained. “The exosatellite is clearly massive enough to be a planet, but it does not orbit a star, though it orbits an object that orbits a star.”
Director Zurlo said the differences between the observed system and our own Solar System have added to the difficulty in labeling the moon-like object.
“We have a clear delineation between the planets and the Sun in the Solar System, so defining things like moons is simple,” Zurlo explained. “In the CD-35 2722 system, where we are blurring the lines between stars, planets, and moons, the whole thing becomes more complicated to describe.”
When discussing the significance of the moon-like object, Director Zurlo said detecting satellites in other systems will help researchers better understand the diversity in formation and evolution of planets, moons, and other moon-like objects. The director also noted the historical nature of the detection.
“As exotic as it is, this system is truly unique and represents a breakthrough: the first plausible detection of an exosatellite,” the researcher explained.
Moving forward, the team said the increased sensitivity of the 39-meter mirror on the ESO’s in-development Extremely Large Telescope (ELT) will allow for the detection of even smaller moons, including potentially spotting moons the size of Earth’s largest satellite. The researchers said such detections will likely force the astronomical community to reconsider how planetary objects are labeled, especially those in systems so radically different from our own.
The study “Planetary-mass exosatellite detected around the substellar companion of a star” was published in the journal Nature.
Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org.
When a meteorite tore through a New Jersey home, the homeowner quickly preserved the fragments. Now, they're giving scientists a look at Earth's early history.
The post New Jersey Meteorite Offers Early Solar System Clues appeared first on Sky & Telescope.
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