Category: Asteroids

Using the James Webb Space Telescope (JWST), scientists have found that the interstellar comet 3I/ATLAS was built from tiny grains of ice mixed with dust that are quite different from the solar system’s comets.

These ice grains do, however, bear striking similarities to some icy bodies located at the edge of the solar system, beyond the orbit of Neptune, so-called trans-Neptunian objects (TNOs).

3I/ATLAS was discovered entering the solar system in the summer of 2025. It was only the third object found entering the solar system from farther afield in the Milky Way after 1I/'Oumuamua, seen in 2017, and 2I/Borisov, detected in 2019. This meant the interstellar comet offered a rare chance to glimpse the conditions under which such bodies form in other star systems. Thus, the JWST was quickly on the trail of 3I/ATLAS.

"We designed [JWST] to be ready the moment an active interstellar comet was found and to follow it over time," Martin Cordiner of NASA’s Goddard Space Flight Center and the Catholic University of America said in a statement.

Cordiner leads the JWST program to study objects such as 3I/ATLAS, and he is a co-author on a new research paper describing some of the findings.

The unclear origins of 3I/ATLAS

Researchers know that 3I/ATLAS wasn't born in the solar system, but nobody knows around which star 3I/ATLAS formed. What scientists are more sure of is the fact that this interstellar comet was produced within a planet-forming disk of gas and dust around a young star, possibly as long ago as 10 to 12 billion years. That's over twice the age of our solar system. It was then ejected from its home system somehow and left to wander interstellar space before encountering our solar system.

Like the familiar comets in our solar system, 3I/ATLAS is composed of grains of ice less than a micron – a millionth of a meter – in size. When the surface of the comet is warmed by the sun, gas erupts outwards, carrying ice grains into the cloud of ice and dust surrounding the comet, its coma, and its tail, where JWST can detect them.

When viewed spectroscopically, the water-ice in comets native to our solar system creates a strong absorption line in a comet’s spectrum at a wavelength of three microns, as well as less-prominent absorption lines at 1.5 and two microns.

Yet when the JWST’s Near-Infrared spectrograph (NIRSpec) instrument viewed 3I/ATLAS three times between August 2025, before its closest approach to the sun, and after closest approach in April 2026, scientists found the 1.5- and two micron absorption lines were missing, though the three-micron line remained strong.

"That combination was a puzzle," research lead author Silvia Protopapa of the South-west Research Institute said. "The strong three-micron band points to water-ice in the coma, but the weak or absent shorter-wavelength bands suggest the ice is not in the form we usually see in solar system comets."

The JWST's muddy 3I/ATLAS findings

Whenever presented with an unusual observational signature such the JWST delievered for 3I/ATLAS researchers turn to modeling to find the physical characteristics that best fit the spectrum.

The modeling suggested to Protopapa’s team that 3I/ATLAS was composed of sub-micron grains of dirty water-ice, rich in dust. In comparison, the grains from the solar system’s indigenous comets are much cleaner, with almost pure water-ice relatively uncontaminated by dust.

"What seems to set [3I/ATLAS’ grains] apart is how much dust is mixed into the ice," said Protopapa. "Those grains hold clues to the conditions where the comet was born."

Comets are made of primordial material found in the planet-forming disk of gas and dust that surrounds a young star, and therefore the composition of comets can provide a window into the conditions in which planets form.

Whereas solar system comets tell us about the birth of Earth, an interstellar comet can tell us about conditions in which planets formed around another star, and how similar or dissimilar those conditions were to the birth of the solar system.

Yet comets are not the only icy remnants that date back to such primordial times. There are various families of bodies in the outer solar system, and 3I/ATLAS’ spectrum bears a resemblance to the spectrum of some medium-sized TNOs that are rich in carbon-dioxide ice and organic compounds (organic meaning containing carbon atoms). Indeed, in a separate 2025 study led by Cordiner, the JWST found 3I/ATLAS to have one of the greatest abundances of carbon dioxide ever seen in a comet.

TNOs are sizable bodies that are located far beyond the orbit of Neptune, The TNOs in question would have formed in a different part of the Sun’s protoplanetary disk than most comets and their composition reflects that.

On the other hand, the results imply that 3I/ATLAS was formed around its star of origin from similar icy material to that which produced some of the TNOs in our solar system, showing that the building blocks of planets around other stars share a common range of properties with the building blocks that formed our solar system. Indeed, 3I/ATLAS could even be a fragment of a TNO-like body that was shattered in a collision.

"At first glance, 3I/ATLAS looks different from the icy comets we know," said Protopapa. "But when we placed it alongside distant icy worlds in our own solar system, it no longer looked out of place.

"This suggests that the icy building block of planets, here and around other stars, may share ice in the form of tiny, micron-scale grains, ranging from relatively pure ice to ice mixed with dust, with 3I/ATLAS toward the dusty end."

What this tells us is that these sub-micron-sized icy grains must form first in planet-forming disks, to then be incorporated into large bodies such as comets and protoplanets.

The team's findings were published on Monday (Oct. 26) in The Astrophysical Journal Letters.

On Sept. 30, NASA formally concluded OSIRIS-REx, the historic first U.S. mission to pluck a pristine piece of an asteroid and deliver it safely back to Earth.

The van-sized OSIRIS-REx spacecraft — whose name is short for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer — visited and sampled Bennu, an ancient space rock holding pristine remnants from the dawn of our solar system more than 4.5 billion years ago. Among those cosmic relics are raw organic building blocks, the kind that may have seeded life on Earth.

"I have known this day was coming for a long time, but it is still difficult to see it arrive," OSIRIS-REx Principal Investigator Dante Lauretta, who's based at the University of Arizona, said in a post on LinkedIn. "I feel enormous pride in what we accomplished together, and real sadness that this journey has come to an end."

For the mission team, the farewell capped a decade of high-stakes engineering, on-the-fly troubleshooting and nail-biting close calls that ultimately delivered to Earth the largest asteroid sample ever collected in space, one that held secrets from the early solar system.

Long before launch, the team faced obstacles that nearly thwarted the endeavor — chiefly, two rejections from NASA — before finally securing the green light for the $1 billion project under the New Frontiers Program in 2011.

When OSIRIS-REx launched on Sept. 8, 2016, on a two-year journey across the inner solar system, Bennu was little more than a point of light in telescopes. Scientists expected the asteroid’s surface to be a smooth, sandy sphere where OSIRIS-REx could seamlessly touch down. Much to their surprise, however, when the probe arrived at the asteroid in late 2018, it revealed Bennu to be a treacherous, loosely bound amalgamation of jagged boulders.

"Our expectations about the asteroid's surface were completely wrong," Lauretta said in an Oct. 7 statement from the University of Arizona. "There was no obvious place to collect a sample anywhere."

When OSIRIS-REx touched down on a small crater named Nightingale, Bennu offered so little structural resistance that scientists said its surface reacted more like fluid than a hard, rocky shell. The spacecraft's sampling head sank directly into the asteroid, stopping after burrowing 20 inches (51 centimeters) deep by firing its thrusters at the right time to pull away, with the precious sample in hand.

Then came another nail-biting moment: The sample collector lid got jammed in a partially open position because so much material was scooped up, allowing fragments of the precious cargo to escape. In a race against time to prevent further loss, the mission team quickly stowed the sampler head directly inside the return capsule, securing the cosmic treasure for its journey back to Earth.

Even the final return to Earth, on Sept. 24, 2023, kept the team on edge: A parachute failed to deploy properly during reentry, forcing a tense but ultimately safe landing in the Utah desert.

"Successful exploration missions are not those that avoid surprises; they are those that are deliberately designed to adapt to them," Lauretta said in the statement, quoting a line from the mission's final report to NASA.

"That certainly describes OSIRIS-REx," he said. "Again and again, the mission presented us with circumstances we had not expected, and again and again, this team found a way forward."

The mission's triumphs began long before the samples reached Earth. For example, the probe set a Guinness World Record when it slid into orbit around the 1,610-foot-wide (490 meters) Bennu, which became the smallest object ever circled by a spacecraft.

The scientific payoff that followed included remote-sensing work that confirmed Bennu's surface is coated in carbon-bearing compounds. Those observations also revealed that Bennu was once part of a much larger, water-rich parent asteroid that shattered in a catastrophic collision in the main asteroid belt between Mars and Jupiter.

The returned sample — which weighs 4.29 ounces (121.6 grams) here on Earth, more than twice the mission's requirement — continues to thrill and occupy scientists.

A wave of research papers, now topping 200, continues to piece together the composition and history of the ancient space rock. Among other findings, Bennu's pristine material has revealed amino acids and sugars that, on Earth, are essential for life, alongside a history of exposure to liquid water that could have served as the "broth" for these compounds to interact.

More discoveries are likely to come. Most of the returned Bennu sample is being preserved for future generations of scientists, who will study it "with questions and instruments we cannot yet anticipate," Lauretta said in the statement.

Though its OSIRIS-REx chapter is closed, the spacecraft itself is far from retired. Renamed OSIRIS-APEX (OSIRIS-APophis EXplorer), the probe is using its remaining propellant to head toward Apophis, another near-Earth asteroid and a different type of space rock from Bennu. It is scheduled to arrive in 2029.

The United Arab Emirates (UAE) has moved a step closer to launching its second-ever interplanetary mission — an ambitious, eight-year exploration of seven asteroids between Mars and Jupiter that will culminate with a landing on the mysteriously red asteroid 269 Justitia.

The mission team unveiled a half-scale model of the homegrown probe that will make that landing during an Oct. 1 press conference in Abu Dhabi, the capital of the UAE. The autonomous craft will ride attached to the main spacecraft MBR Explorer, named after Sheikh Mohammed bin Rashid al-Maktoum, the ruler of Dubai and the UAE's prime minister.

The flight-ready lander is being kept pristine in a vacuum chamber in the capital before being transported to Colorado by Etihad Airways, officials said, where it will be integrated with the main spacecraft, which was developed by the UAE Space Agency.

If all goes to plan, the mission will lift off from Japan in March 2028, kicking off the Emirates Mission to the Asteroid Belt (EMA). The project is an ambitious follow-up to the UAE Space Agency's Hope Mars orbiter, which has been studying the Red Planet since 2021.

"It's a proud moment for us here at the UAE," said Faisal al-Bannai, the secretary general of the Advanced Technology Research Council in Abu Dhabi.

'We don't know what we're going to find'

EMA will conduct high-speed flybys of six asteroids before reaching and orbiting 269 Justitia. It will travel a total of about 3 billion miles (5 billion kilometers), which is equivalent to circling Earth roughly 125,000 times, said Najwa Aaraj, the CEO of the Technology Innovation Institute (TII) in Abu Dhabi, which designed, built and tested the mission's lander.

Along the way, the MBR Explorer will utilize gravity assists from Venus and then Earth to swing deeper into space, zipping past its first three asteroid targets: 10253 Westerwald, 623 Chimaera and 13294 Rockox. A subsequent gravity assist from Mars will fling the spacecraft even farther out, guiding it past three more space rocks: 88055 Ghaf, 23871 Ousha and 59980 Moza.

By 2036, the spacecraft is scheduled to rendezvous with its final and most intriguing target, 269 Justitia. A roughly 30-mile-wide (50 km) object in the middle of the asteroid belt, 269 Justitia is unusual for its remarkably crimson hue.

Its distinct color more closely resembles icy objects in the Kuiper Belt beyond Neptune than its immediate main-belt neighbors. This unique trait has led planetary scientists to hypothesize that the asteroid formed in the frigid outer solar system and migrated inward early in the solar system's history. If true, visiting 269 Justitia would offer a rare, close-up look at pristine material from the distant outer solar system via a much shorter journey.

Scientists are particularly excited that the asteroid may still hold water-related minerals and organic compounds preserved from its origins. Studying its surface could therefore offer clues to how water and organic material were distributed as planets began to form, Elias Tsoutsanis, a chief researcher at TII's propulsion and space research center, said during the press briefing.

"We don't know what we're going to find — that's exploration," Tsoutsanis told reporters. "We're really excited."

According to the mission plan, the MBR Explorer will spend roughly seven months studying 269 Justitia from orbit. Beginning at an altitude of 155 miles (250 km), the spacecraft will gradually lower its path before releasing the lander. The smaller probe will then head toward the asteroid's surface, a descent that should take two to three hours depending on 269 Justitia's precise gravity, which remains unknown.

Although TII describes the mission ending with a landing on the surface of 269 Justitia, the engineering details suggest a more violent endgame. Cruising toward the asteroid's surface at 15 to 27 meters per second (34 to 60 mph) with no meaningful way to slow down, the probe will function less like a traditional lander and more like a planned impactor.

"We don't expect that the probe will survive the touchdown," said Mariam Alhammadi, a researcher in TII leading the mission's electric propulsion.

To ensure its two onboard cameras capture essential imagery during the descent, the probe will rely on an attitude-control system to counteract any post-separation spin, Alhammadi said. Should the probe unexpectedly survive the hard landing, she added, its battery is built to last 20 to 50 minutes, providing a narrow but crucial window for it to beam close-ups of the asteroid's surface back to Earth.

The high-velocity impact is also expected to dig a small crater on 269 Justitia, possibly exposing pristine subsurface material. Because this material cannot be imaged from orbit, the team expects the probe's final images to be among the most valuable of the entire mission.

Zero margin for error

Back on Earth, the team faces an unforgiving timeline. To execute the planned flybys, the mission must launch during a narrow three-week window that opens in early March 2028.

"God forbid we miss that — we basically don't have a mission," Mohsen al-Awadhi, the mission director at the UAE Space Agency, told reporters at the press conference. The orbital mechanics are so rigid that another comparable opportunity will not arise for at least 100 years, prompting al-Awadhi to add that he is devoting no time and energy to a backup plan.

Meeting the launch window is just the first hurdle, however. Once deployed in deep space, the lander must operate with absolute autonomy, receiving no commands from Earth or the main MBR Explorer spacecraft, the team says.

"In these eight years, I have no control to call it back — so nothing can go wrong," said Aaraj.

The team is confident that rigorous engineering and testing have produced a probe that can essentially "think for itself." Equipped with AI, it is designed to decide on its own when to capture images and how to filter and rank the most valuable data. Rather than waiting until it reaches its destination, the lander will take images throughout its eight-year cruise and send the best ones back to Earth roughly every six months, according to a TII statement.

Officials declined to disclose the mission's overall cost or say whether it has stayed on budget. The United States' ongoing war in Iran has sparked missile and drone attacks across the UAE, but the mission team has persevered: WIRED reported that they pressed on even as missiles were intercepted overhead.

Looking ahead

Beyond the immediate scientific return, officials said a central pillar of this mission is accelerating the UAE's sovereign deep-space capabilities and fostering its domestic space economy.

The UAE Space Agency, established in 2014, has steadily expanded its portfolio from satellite launches to a Martian orbiter and sending two astronauts to the International Space Station. The EMA probe represents a developmental leap, designed and built in just under two years by a team of roughly 50 local engineers and scientists, many of whom began their careers as entry-level technicians on the Hope Mars mission.

"I don't want to call them my kids — there's a lot of them — but that's how attached I feel to them," al-Awadhi said during the briefing.

The UAE aims to position itself among the world's 10 largest space economies by 2031, targeting a massive expansion of a sector currently valued at about $12 billion. According to al-Bannai, the EMA project is designed to be one of many programs to come. By the time the lander impacts 269 Justitia in 2036, the technology matured during this journey will already be driving the next generation of Emirati spacecraft, he said.

"That's the journey we're on today."

New images reveal what astronomers believe is the first-known "trilobate" or three-headed asteroid in our solar system.

What is it?

These new images capture the asteroid known as (44) Nysa, or just Nysa, as it spins through the main asteroid belt located between Mars and Jupiter. The images were captured with the Very Large Telescope in Chile and the Large Binocular Telescope in Arizona.

Nysa was first observed in 1857, but it wasn't until the new images were captured when scientists were able to resolve its unique three-headed structure. The asteroid appears to be around 47 miles (75 kilometers) in circumference at its widest point, with two narrow "necks" that give it its odd "trilobate" shape.

Even more incredible, astronomers were also able to resolve that a 0.6-mile-wide (1-km-wide) moon seems to orbit Nysa. The tiny moon, currently known as S/2026 (44) 1, appears to orbit the asteroid at a distance of around 106 miles (170 km).

Why is it incredible?

Astronomers say these images reveal (44) Nysa to be unlike any other asteroid we've seen in our neck of the cosmic woods.

"The images reveal a remarkably unusual object," said Kate Minker of Arizona's Lowell Observatory in a statement announcing the discovery. "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."

Scientists can study asteroids like Nysa to learn about how the planets of our solar system formed. Nysa belongs to a class of asteroids believed to have formed closer to the inner solar system and therefore may have a similar composition to the building blocks that would go on to form the inner planets.

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.

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.

Three years before the skyscraper-size asteroid Apophis makes its very close (but safe) flyby of Earth, scientists have already begun charting exactly when and where billions of people can watch it sweep across the sky.

Speaking at an "Apophis T-3 Years" workshop held earlier this month at the University of Padua in Italy, retired cartographer Michael Zeiler and astronomer Rick Fienberg shared detailed visibility maps charting the asteroid's passage across Earth's skies.

According to their calculations, roughly 90% of the world's population — about 7.6 billion people — lives in regions where Apophis could, in principle, be seen with the naked eye on April 13, 2029. The actual viewing success will depend more on earthly considerations, however, including cloud cover and the extent of light pollution.

Known formally as 99942 Apophis, the space rock will not resemble a blazing meteor tearing through the sky. Instead, scientists say it will appear as a point-like speck of light gliding steadily across, which, at its closest approach, will appear to move by about the apparent width of the full moon every minute.

"It will definitely be noticeable," Fienberg told Space.com. "It's going to be moving more slowly than a satellite — it will cross the sky in hours, rather than minutes, and it will just be a point."

According to the new maps, the asteroid should remain visible to the naked eye for about seven hours, beginning over Australia at 11:00 a.m. EDT (15:00 UTC) and concluding over the North Atlantic at 6:00 p.m. EDT (22:00 UTC).

At 4:35 p.m. EDT (20:35 UTC), Apophis is expected to reach its greatest apparent brightness as it passes over Cameroon, offering prime viewing to an estimated 3.9 billion people across Africa, Asia, eastern South America and parts of Europe.

About an hour later, at 5:45 p.m. EDT (21:45 UTC), the asteroid will make its closest approach to Earth, passing about 19,700 miles (31,600 kilometers) above the North Atlantic — well inside the orbit of Earth's geostationary satellites. The event would be visible across much of South America, the United States, Africa and parts of Europe, reaching roughly 2 billion people.

"This is the first time we've been able to predict in human history an asteroid visibly passing by the Earth," Richard Binzel, a professor of planetary sciences at the Massachusetts Institute of Technology (MIT), said during the workshop. "That's part of a shared experience."

As excitement ramps up for the once-in-a-millennium spectacle, Binzel opened the workshop with three messages: "Apophis will safely pass the Earth. Apophis will safely pass the Earth. Apophis will safely pass the Earth."

That absolute certainty is the hard-won fruit of more than two decades of increasingly precise observations. When Apophis was discovered in 2004, early calculations suggested a 1-in-37 chance of an impact in 2029, making it the most potentially hazardous asteroid known at the time. Additional observations steadily refined the asteroid's orbit, eliminating any possibility of a collision in 2029 and also ruling out any impact threat for at least the next century, according to NASA.

With the impact threat removed, scientists now view the flyby as a rare opportunity to observe how Earth's gravity affects an asteroid during an exceptionally close encounter.

Our planet's gravity is expected to tug the asteroid into a new orbit around the sun without posing any future danger. During the flyby, however, those same gravitational forces may stretch and squeeze the asteroid enough to trigger landslides or expose pristine material hidden beneath its weathered surface. Or they may do almost nothing.

"We simply don't know what's going to happen," Binzel said during the workshop. "Apophis may go by and not care too much, or maybe we'll see something significant."

"That's why we have to look," he added. "We're gonna learn a lot either way."

At the workshop, scientists said they hope to monitor the flyby from observatories in Spain's Canary Islands, among other places, as its location in the Atlantic Ocean offers an ideal view of the asteroid's closest approach as well as favorable prospects for clear skies.

Japan's Hayabusa2 sample-return spacecraft is on target to make one of the closest ever flybys of a near-Earth asteroid in early July, as part of its extended mission campaign.

Hayabusa2 launched in December 2014 and rendezvoused with the asteroid Ryugu four years later. The spacecraft collected samples and delivered them to Earth in 2020, completing its primary objectives. But the hardy spacecraft still has bold plans to deliver new and exciting science data.

The spacecraft has been operating well, despite needing to briefly enter a protective safe mode last year, and now is set to make a flyby of the asteroid Torifune on July 5, Satoshi Tanaka of the Japanese Aerospace Exploration Agency (JAXA) said in a presentation on Hayabusa2 during the 35th Meeting of the NASA Small Bodies Assessment Group (SBAG) on June 11.

The flyby will see Hayabusa2 get within 1 to 10 kilometers (0.62 to 6.2 miles) of Torifune, using its instrument suite to study the roughly 450-meter-wide (1,476 feet) asteroid as it whizzes past at 5.3 kilometers per second (3.3 miles per second).

"This is one of the closest asteroid encounters ever attempted by a mission of this class," Tanaka said. "By combining advanced navigation techniques and the engineering capabilities of Hayabusa2, we have made it possible to achieve a flyby at a distance of only about 1 kilometer."

Torifune was first given the designation 2001 CC21 before being named for a deity from Japanese mythology. Tanaka says the asteroid is somewhat similar to Itokawa — the target of Japan's first Hayabusa mission — but little is known for sure about Torifune, adding a level of uncertainty to this extended mission objective.

"It's still a risky operation, because they had not planned for this," Patrick Michel, the principal investigator for the European Space Agency's Hera asteroid mission and part of the Hayabusa2 science team, told Space.com. "The second thing is that we have a high uncertainty on the size of the object," he added, with the dimensions of the asteroid unknown.

The asteroid could, for example, be a contact binary, according to Michel, in which two separate bodies came together at low velocities. Known contact binary small bodies include the Kuiper belt object Arrokoth, imaged by NASA's New Horizons, and comet 67P/Churyumov-Gerasimenko, described as a "rubber duck" when visited by ESA's Rosetta spacecraft.

"We're going to discover what it looks like. And each time we have seen a new asteroid, we've been surprised," Michel said. "We're going to discover another beast to put in the zoo of asteroids."

The very high velocity of the flyby means there will be limited time to collect images and other data on the asteroid, but the rapid encounter will also provide a useful test for planetary defense, as well as adding to planetary science.

The flyby, using advanced navigation techniques to guide and control the spacecraft, will be a useful test of a rapid reconnaissance concept that could be used to determine the physical properties of an asteroid. Such reconnaissance could provide vital information before intercepting a threatening asteroid with a kinetic impact, as demonstrated by NASA's DART mission in 2022.

Tanaka said that Hayabusa2 has been busy during its deep space cruise phase, including making observations of the zodiacal light and exoplanets, and the Torifune flyby will, hopefully, not be its final act. The ultimate goal of the Hayabusa2 extended mission is to visit the tiny asteroid 1998 KY26 in 2031, which would be the smallest asteroid ever visited. The spacecraft could even attempt to land on the miniscule world, which is just 11 meters (36 feet) wide.

The oldest known asteroid impact site on Earth was created 3.02 billion years ago in what's now Western Australia — not far from where we've seen the oldest traces of life on our planet.

A rock formation in Western Australia's Pilbara region seems to offer evidence of an asteroid slamming into Earth's newly-formed rocky crust around 3.02 billion years ago. That makes the formation, called the North Pole Dome, the oldest evidence of an asteroid impact on Earth, according to a recent study, which dated crystals in the rocks shocked and reshaped by the impact's tremendous heat and pressure.

It's the latest salvo in an ongoing debate about the age of the crater (or what's left of it after billions of years of erosion), and there's more at stake than bragging rights: a crater dating back this deep in Earth's distant past could shed light on the rise of the continents and the origin of life.

A rare glimpse

Inside most rocks in Earth's crust, tiny grains of mineral called zircon quietly record the passage of eons. Zircon contains tiny amounts of uranium, which slowly but steadily breaks down into lead; that steadiness is key, because the ratios of those two elements reveal how long it's been since a grain of zircon crystallized from hot, molten rock. In this case, zircon grains told Kirkland and his colleagues that it had been about 3.02 billion years since the tremendous heat and pressure of an asteroid impact melted zircon crystals in the rocks around North Pole Dome.

"Some zircons at the North Pole Dome have unusual branching, skeletal shapes," Kirkland said in an emailed press release. "We interpret these as impact-modified crystals, formed when older zircon was disrupted, partly recrystallized, and in places, regrown during the intense heating caused by the impact."

If Kirkland and his colleagues are right, the area, also called the Miralga Impact Structure, is the oldest trace of an asteroid colliding with our planet. The newly published date makes Miralga a relic of a tumultuous period in our solar system's history, called the Late Heavy Bombardment, when the giant planets were still jockeying for position in their orbits around the sun, flinging asteroids and comets toward the inner solar system in the process (or so cosmologists theorize). Amid this rain of space rocks, Earth was midway through the Archaean Eon, with the planet's surface finally cooling to form a thin crust of solid rock. Earth's surface lay beneath an orangish haze of methane, a little like a warmer version of Saturn's moon Titan.

And somewhere in there, the first life took shape.

The oldest traces of that early life are just a few kilometers from North Pole Dome: limestone stromatolites, made of layers of tiny sediment grains trapped in, and eventually left behind by, sheets of early bacteria. The ones in Pilbara are about 3.5 billion years old, another date courtesy of zircon grains. If the Miralga impact happened 3.02 billion years ago, it struck a world already teeming with overlapping mats of bacteria.

The oldest known Earth rock, a 4.35-billion-year-old sandstone formation (also dated using zircon), lies just a few hundred kilometers south of Pilbara, in the Jack Hills. Why is all of this — the oldest rocks, the oldest asteroid crater, and the oldest traces of life — in Western Australia? It's reasonably likely that crust formed, life emerged, and meteors smashed into the ground millions of years earlier, in places all over the world, but the evidence just happened to be preserved in this area of Australia. Most of Earth's very oldest rocks have long since been reworked by plate tectonics or erosion, basically erasing the first chapters of our geological record.

A heated debate about heated rock

"While the site had previously been identified as an ancient impact crater, its exact age remained uncertain," said Kirkland.

Last year, Kirkland and his colleagues proposed that the impact dated back to 3.47 billion years ago, almost the same age as the nearby stromatolites. In that same paper, the team suggested that the original crater – whose outline has long since eroded away, leaving behind only impact-shocked rocks and tantalizing hints – might have been up to 62 miles (100 km) wide. The 22-mile-wide (35-kilometer-wide) North Pole Dome itself seemed to mark the crater's center; rock in the middle of large craters often rebounds upward after the impact, leaving a peak or dome behind (picture the way the middle of a trampoline flexes upward, captured in a freeze frame).

But another group of geoscientists published a paper a few months later, arguing that Miralga (a name they gave the crater, based on the local Aboriginal peoples' name for the area) couldn't be any more than 2.7 billion years old, and only 10 miles (16 km) wide. That's still substantial, and old enough to be interesting, but too young and too small to have played much of a role in shaping the region's life, or its continental crust.

"By the time of the impact, the Pilbara was already quite old," wrote the study’s authors in an essay at the time (of the paper, not the impact).

The teams agreed on, basically, one thing: the area around North Pole Dome was definitely an impact site, and dating very old rocks is not easy. Both 2025 papers looked at the placement of rocks called shatter cones, which form when the shockwaves of an impact (or, sometimes, an underground nuclear bomb test) pass through rock, leaving behind ripples, striations, or cracks. But based on where the shatter cones appeared in relation to other rock layers, the two teams of scientists drew very different conclusions.

"Ancient craters are incredibly difficult to date, because over billions of years, rocks are altered by heat, pressure, and fluids, which can obscure or reset the original impact signatures," said Kirkland, whose team now argues that the zircon crystal dates are much more precise than either team's previous efforts. "What we've been able to do here is separate the moment of impact from its long geological history."

Curtin University geoscientist Chris Kirkland and his colleagues published their work in the journal Geology.