Van Gogh’s ‘The Starry Night’ depicts the sky on July 22, 1889, researchers find

Researchers think they might have pinpointed the exact night sky that we see depicted in Vincent van Gogh's iconic painting "The Starry Night."

Perhaps one of the most famous paintings in modern history, Van Gogh's "The Starry Night" carries a legacy that continues to inspire and mystify generation after generation. But while you might see in its swirls of color and bright spots of starlight a night sky derived purely from imagination, some scientists think it represents an actual view — one that includes a waning crescent moon, Venus and the Hyades cluster. And they may know exactly when this sky appeared..

In a new study, researchers suggest that "The Starry Night" depicts the pre-dawn sky seen around July 22, 1889 from Saint-Rémy-de-Provence, where Van Gogh painted it. But while this sky happens to perfectly match the one depicted in the artwork, art historians have long thought that Van Gogh painted this piece in June. Could these findings shift the date of this legendary artwork?

Finding a painted sky

This investigation started decades ago with art historian Albert Boime and astronomer George Abell at UCLA in 1984 and continued in the following years with astronomer Charles Whitney at Harvard University. However, these earlier analyses did not agree with one another, and there was no true consensus about exactly when the sky matched with the painting.

So the question remained, lingering in the minds of those with a shared love for both art and space. And a team led by Elijah Jeong-hyun Kim, the CEO of South Korean robotic telescope company SLLAB and a Ph.D. candidate at Kyung Hee University's School of Space Research, picked up the search once more.

"When they see a fragment of a starry sky, observational astronomers like me and amateur astronomers alike will want to solve the puzzle. I am simply someone who pursued that process a little more actively," Kim told Space.com.

The central cluster of stars in The Starry Night (1889), left, and the Hyades cluster in Taurus, center.

A figure from Kim et al.'s paper in Scientific Reports. According to the figure: "The central cluster of stars in The Starry Night (1889), left, and the Hyades cluster in Taurus, center. At right, the five stars in the painting (orange) are overlaid on the real stars (blue) after matching for size, orientation and position; red dashed lines show the residual differences." (Image credit: Kim et al., Scientific Reports (2026))

But how did Kim's team come to their conclusion, after others had failed to nail down a date over the decades? In short, "we analyzed the painting astronomically, analyzed documents about his situation in July 1889, and then carried out ecological and meteorological investigations," Kim said.

To start with, the team analyzed the sky from the exact location in Saint-Rémy where Van Gogh is said to have painted "The Starry Night." They then used observational geometry to map the historical night sky.

"Modern telescopes are equipped with a function called astrometry, which compares an image of the night sky with celestial coordinates stored in a computer and automatically extracts the coordinates of the image," Kim said. "We used Procrustes analysis, a method that compares only the 'shape' of two sets of points. After matching their position, size and rotation, it measures how similar the two shapes are from the differences that remain (the residuals)."

"Because a star cluster on the canvas may be larger or smaller than in reality and slightly tilted, this method was the right fit. It allowed us to explain, in quantitative terms, what earlier studies had described only qualitatively as 'resembling a certain constellation,'" Kim added.

But this quantitative analysis wasn't enough to say for sure that this was the right-fitting sky, as different constellations could fit to a similar degree, Kim explained. To get closer to their answer, the team combined their analysis with a deep dive through history.

"We also checked whether the stars were actually in that part of the pre-dawn sky on that date, whether they fall within the painter’s field of view, and whether the appearance of the moon and Venus matches the painting. It was the Hyades that satisfied all of these conditions," Kim said.

Exploring astro-art history

As mentioned, the date of this matching sky comes in late July, a month after art historians think Van Gogh painted "The Starry Night." But the researchers suggest that their findings could provide evidence to support the idea that the work was actually painted in July.

Letters written by Van Gogh as early as 1888 describe his desire to paint a star-filled sky. A letter dated April 12, 1888 reads: "A starry sky, for example, well — it’s a thing that I’d like to try to do, just as in the daytime I’ll try to paint a green meadow studded with dandelions."

Kim followed these letters through the months to try and find more information that could potentially alleviate the discrepancy between the matching skies and the actual month the painting was created. Kim pointed to a letter from between late May and early June 1889 that reads: "This morning I saw the countryside from my window a long time before sunrise with nothing but the morning star, which looked very big."

Kim drew on "personal imagination" to find ties between Van Gogh's sky observations in these months and what they might mean for the painting's timeline, Kim shared, so this doesn't definitively change the view of this painting's history. However, Kim suggested that these records could indicate that Van Gogh was repeatedly looking up and watching the pre-dawn sky, which could have led to him seeing this exact sky on July 22.

The painting itself even ignites uncertainty among art historians. As the researchers cite in their new paper, leading art historians see "The Starry Night" as stylistically different from Van Gogh's other works during the month of June, drawing further questions over the date painted.

"What our study shows is that the sky in the painting matches, in both observation and shape, the real pre-dawn sky around July 22. So, what we propose is the possibility that Vincent conceived the idea in June and completed the painting after July 22," Kim said.

However, "I think further research in art history and conservation science could shed more light on this question," Kim added.

This work was described in a study published Oct. 22 in the journal Scientific Reports.

Australia’s bizarre ‘Spider Crater’ seen from orbit | Space photo of the day for Oct. 22, 2026

An image from space of spider crater on Earth.

A satellite image of "Spider Crater" in Western Australia. (Image credit: NASA Earth Observatory image by Michala Garrison, using Landsat data from the U.S. Geological Survey)

From the dangerous Sydney funnel-web to the common huntsman, Australia is home to its fair share of spiders. It even has a crater shaped like one.

What is it?

One stretch of the vast Western Australia wilderness is imprinted with a curious crater, which likely formed after a meteor impact hundreds of millions of years ago. Geologists think the spider-like pattern in the crater's center was created when its floor rebounded following the initial impact, NASA has said.

In the hundreds of millions of years since the initial impact, erosion has continued to carve this formation into its current, signature shape. Complete with "legs," the planetary imprint has earned its name Spider Crater.

This image shows the impact structure in its entirety, which stretches 8 by 7 miles (13 by 11 kilometers) in full, with the central "spider" piece measuring 2.5 miles (4 km).

Why is it incredible?

In this image, we can see this "spider" from space. This snapshot shows the geologic feature as captured by the OLI (Operational Land Imager) aboard the Landsat 9 satellite, an Earth-observing craft that launched back in 2021.

The satellite, a collaborative effort between NASA and the U.S. Geological Survey, is the ninth in the Landsat Earth-observing series, which goes all the way back to the launch of Landsat 1 in 1972. On a near-weekly basis, Landsat 9 delivers observations of everything from deforestation to water quality and crop growth.

The series of Landsat satellites have been a critical piece in the modern understanding of how our planet continues to change. Whether it's the repercussions of climate change or fluctuations in agriculture, observations from orbit do more than provide interesting photos of our home world; they also capture critical data.

The view from the edge of a sparkling spiral galaxy | Space photo of the day for Oct. 20, 2026

The side-view of a spiral galaxy.

The spiral galaxy NGC 1827, as seen from the side by the Hubble Space Telescope. (Image credit: NASA, ESA, Michael Jones (California Institute of Technology); Image Processing: Gladys Kober (NASA/Catholic University of America))

If you were approaching the edge of a spiral galaxy, arriving from afar through the cosmos, it might look something like this.

What is it?

In this new snapshot by the Hubble Space Telescope's Advanced Camera for Surveys (ACS), we can see the edge of the spiral galaxy NGC 1827. Found about 37 million light-years from Earth, this galaxy sparkles in this side-on view.

Not all spiral galaxies are the same. This galaxy is what is known as an "intermediate" spiral, which means that its structure sits somewhere between that of a barred and unbarred spiral galaxy. Barred galaxies have a distinctive central, bar-shaped structure, while the unbarred variety lacks this bar and can look more like circular spirals.

NGC 1827's spiral shape isn't clear from the side, however. From this perspective, we see its twinkling edge, speckled with stars and woven together with brown ribbons of dust.

Why is it incredible?

Beneath the beauty of this spiral edge lies an expansive, cosmic landscape. Bright blue stars dot the spiral's side, with one particularly luminous star taking the spotlight with four diffraction spikes — created by light bending through the inner workings of Hubble's camera — emanating from its center.

This image was captured as part of a larger Hubble survey that's exploring 260 satellite galaxies, which are galaxies gravitationally bound to larger hosts. Hubble is specifically looking to survey satellite galaxies that lie near host galaxies similar to our own Milky Way.

So far, Hubble has spotted 111 such satellites and will continue to observe, hunting for the rest.

By studying satellite galaxies like this one, which also happens to be an especially low-mass galaxy, researchers could better understand the complicated dynamics both within the galaxies themselves and between them and their host galaxies.

NASA closes the book on epic OSIRIS-REx asteroid-sampling mission: ‘I am immensely proud of what we did’

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.

A spacecraft's arm above a moving ground. It's black and white and the ground looks pebbled and rocky.

NASA's OSIRIS-REx spacecraft captured this series of images of asteroid Bennu on April 14, 2020, during the first rehearsal of the mission's sample collection event. The actual sample retrieval was extremely close to the way this looks. (Image credit: NASA/Goddard/University of Arizona)

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 moon is shrinking. 10,000 cracks on the lunar surface reveal by how much

The moon is shrinking, and scientists are narrowing in on exactly how much our natural satellite has dwindled over the years.

The moon is thought to have formed from a violent collision between a massive object and our young Earth roughly 4.5 billion years ago, and its interior is still gradually cooling off from this ancient collision. As it cools, the moon contracts, leading to a long, slow shrinking process. Now, in a new study, scientists think that they have figured out how much smaller the moon is actually getting.

In this new study, scientists analyzing images snapped by the Lunar Reconnaissance Orbiter Camera (LROC) have spotted over 10,000 young faults, or cracks across the moon's surface. This helped them to figure out how much the moon has contracted over time, and they now estimate that the moon's radius has decreased by about 148 feet (45 meters) over the past 400 to 800 million years.

"The number of these young faults revealed in LROC images is much greater than I ever imagined," study lead Thomas Watters, a geologist and scientist emeritus at the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum, said in a statement. "As the interior of the moon continues to cool and contract, it is expected that the growth of existing faults and formation of new faults continues today."

Lobate scarps on the moon.

Lobate scarps on the lunar surface, as seen by LROC. (Image credit: NASA/KARI/ASU/Intuitive Machines/Smithsonian  )

With these LROC observations, researchers in this study saw a variety of different types of cracks and landforms across the lunar surface. This included lobate scarps, or long, curved structures that form when the moon's surface contracts, cracks and is pushed upwards; and small mare ridges, or narrow "wrinkles" in the lunar surface, across the dark plains on the moon.

Lobate scarps on the moon.

Lobate scarps on the moon, as seen by LROC. (Image credit: NASA/KARI/ASU/Intuitive Machines/Smithsonian)

Tectonic activity on the moon looks a lot different than it does on Earth. On our own planet, there are about 15 major tectonic plates. On the moon, there are no tectonic plates at all. Instead, the moon has a single-plate body meaning its outer shell is a single piece only broken by faults or other such cracks created by the moon contracting. This means that instead of faults or cracks appearing at tectonic plate boundaries, they are instead scattered all over the moon.

A global map of lunar faults.

A global map of lunar faults. Red lines indicate over 8,900 lobate scarps while blue lines show over 2,000 small mare ridges. (Image credit: NASA/ASU/Intuitive Machines/Smithsonian)

By mapping these thousands of different features, all created from the moon cooling and contracting over time, the researchers are piecing together lunar history. In addition to finding the extent to which the moon has shrunk over time, they also found that some areas of the moon are covered in many more faults than other areas, and the areas with fewer cracks and faults have thicker moon crust.

This led them to conclude that not only are these areas with thicker crust more stable, but they suggest that a great deal of the widespread cracks in the lunar surface were created later in the moon's history as, in its earlier years, its thick crust would have insulated the moon's warm interior and prevented cooling, contracting and cracking.

This work was described in a study published Oct. 14 in The Planetary Science Journal.

‘They’re kind of goth’: NASA spacecraft gives mysterious brown dwarfs a close-up

Using NASA’s SPHEREx spacecraft, astronomers have studied a host of "failed stars," also known as brown dwarfs.

These strange cosmic bodies straddle the line between planets and stars, possessing a mass between 13 and 80 times that of Jupiter (0.013 to 0.08 times the mass of the sun). They get the nickname failed stars because they form like stars from collapsing clouds of gas and dust but fail to gather enough mass to trigger the fusion of hydrogen to helium in their cores, the process that powers actual stars.

This formation process also means that brown dwarfs are cosmic loners, wandering the darkness of space alone, bereft of the light of a parent star. That description might sound like lyrics from a Type O Negative song ("Black No. 1," anybody?). And that's apt, according to the leader of the new study, which reveals that, chemically speaking, the atmospheres of these dark and cloudy worlds are not unlike those of our solar system's gas giant planets.

"They’re kind of goth," Zafar Rustamkulov, of the California Institute of Technology (Caltech), said in a statement. "Unlike exoplanets, free-floating brown dwarfs are completely independent celestial objects that will fade into eternity alone. We’re still learning how complex they are."

Rustamkulov added that, from Earth orbit, SPHEREx — short for Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer — sees wavelengths of light that are nigh-impossible to see with telescopes on the ground because water in Earth’s atmosphere absorbs them. That is important for bringing brown dwarfs into the light.

"We are picking up light from the deep, red clouds of brown dwarfs all over the sky," he said.

A forest (of brown dwarfs)

Brown dwarfs have been somewhat mysterious since their discovery in the 1990s, due to the fact that the small amount of nuclear fusion that occurs within them causes them to emit no more than a faint glow. That means that our understanding of their makeup, their storms, and their evolution really only comes from theory.

To help lift this observational darkness, the team turned to data from SPHEREx. They studied 37 nearby brown dwarfs in a spectrum of light including 102 wavelengths, from the deepest red our eyes can see to the invisible infrared light. These local failed stars spanned the full temperature range for brown dwarfs — from 4,000 degrees Fahrenheit to minus 10 degrees Fahrenheit (2,200 to minus 20 degrees Celsius).

Considering that the temperature of the sun is about 10,000 degrees Fahrenheit (5,500 degrees Celsius), you could definitely say brown dwarfs run cold.

96 boxed blobs of orange, blue, white, and yellow

Brown dwarfs observed by SPHEREx. (Image credit: Zafar Rustamkulov/NASA/JPL-Caltech)

The spectra of brown dwarfs seen by SPHEREx allowed the team to determine that their atmospheres are chemically rich in water, carbon dioxide, carbon monoxide and methane.

"We’re seeing the signatures of these molecules and how they change from object to object across the entire temperature regime," said team member J. Davy Kirkpatrick, also of Caltech. "Our paper concentrated on just three dozen, but we have thousands more that we are in the process of analyzing.

"I really want to see what bounds the universe places on the variety of brown dwarfs."

All my colors

Brown dwarfs have been routinely observed by other telescopes, including NASA's James Webb Space Telescope and the agency's now-retired Spitzer Space Telescope, but the wide wavelength coverage of SPHEREx has made it particularly useful in observing these failed stars. That's good news for astronomers waiting for change in the atmospheres of brown dwarfs as they age and grow cold.

The researchers found that some brown dwarfs observed by SPHEREx are at a stage of extreme change in which their clouds are clearing, creating atmospheres rich in methane.

The team may have discovered significant new details about brown dwarfs, but they are still on the proverbial mystery street when it comes to these strange celestial objects,

"The state-of-the-art models are capturing the general chemical trend, but when it comes to these cloudy transitions, the models are struggling to match the data," said Rustamkulov. "No two brown dwarfs are alike. Even at the same temperature, their spectra look quite distinct."

NASA’s SPHEREx reveals molecules like methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) in brown dwarf atmospheres. The telescope’s view of three different brown dwarfs appears on the left

NASA’s SPHEREx reveals molecules like methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) in brown dwarf atmospheres. The telescope’s view of three different brown dwarfs appears on the left. (Image credit: Zafar Rustamkulov/International Gemini Observatory/NOIRLab/NSF/AURA, M.H. Wong (UC Berkeley) et al. Acknowledgments: M. Zamani)

"This journey has turned many of us into accidental meteorologists. We know how hard it is to predict weather on our own planet, and we realize it's going to be just as challenging to explain the phenomena we see in these bizarre, cold objects," Kirkpatrick said. "The findings are a call to action to explore even more of these dark worlds."

As astronomers resond to that call to action, I will ponder how I could have worked Bauhaus' Goth classic "Bela Lugosi is Dead" into this article.

The team's research was published on Sept. 28 in The Astrophysical Journal.

Elephant Island is an icy sight from orbit | Space photo of the day for Oct. 19, 2026

Ice floats by in West Antarctica as winter comes to an end in the Southern Hemisphere. (Image credit: contains modified Copernicus Sentinel data (2026), processed by ESA)

Antarctica is a magnificent sight, and that beauty is visible all the way from space.

What is it?

Orbiting planet Earth, the European Space Agency's (ESA) Copernicus Sentinel-3 mission captured a close-up of West Antarctica.

Winter is ending in the Southern Hemisphere, meaning this is the peak of icy weather and sea ice in the Arctic.

In this image snapped by Sentinel-3, you can see a massive swath of ice which includes Elephant Island on the left-hand side. An ice-covered island off the Antarctic coast, Elephant Island floats in the Southern Ocean. It got its name both from the island's shape, which some liken to that of an elephant's head, and the fact that the island is home to a community of elephant seals.

Why is it incredible?

While a seal-inhabited island on the left floats near the Antarctic coast, across the water is a vast, frozen landscape. In just this snapshot, you can see about between 746 and 1,056 miles (1,200 to 1,700 kilometers) of the icy continent.

This image was captured on Sept. 30, 2026. In the Southern Hemisphere, that was just past the end of winter. The absolute peak for sea ice in Antarctica fell just a couple weeks before, on Sept. 14, according to the National Snow and Ice Data Center, ESA reported.

So in this one snapshot, we can see a near-maximum for sea ice in the Antarctic, spanning hundreds of miles. In observing our own planet from space, we are able to peer across vast landscapes, capturing important observational data. This is especially critical for the Antarctic as, with the progression of climate change, this sea ice continues to dwindle, adding to sea level rise among other serious consequences across the planet.

Did a giant object collide with Earth to form the moon?

For as long as humans have watched the night sky, we have wondered about the moon, pondering everything from its alien appearance to its influence over phenomena on Earth such as ocean tides, climate stability, and even the natural rhythms of many organisms.

Among the many questions we have about Earth's lone natural satellite, one remains preeminent: what are the moon's origins, and how long has it orbited Earth?

Today, the leading theory among astronomers is that deep in our planet's past — perhaps within roughly the first 100 million years of solar system history — Earth collided with a planet-sized object, creating the moon within a period that may have been as short as just a few hours. Known as the giant-impact hypothesis, this proposed event involves a hypothetical Mars-sized protoplanet astronomers call Theia. The material ejected into orbit by the powerful impact in question would have accumulated afterward, forming the moon that we observe today.

What do we know?

Birth of a lunar origin hypothesis

The evolution of this striking solution to one of the moon's most enduring mysteries goes back to 1946, when geologist Reginald Aldworth Daly was among the first to suggest that an impact event might explain the formation of the moon.

Before Daly, scientists had been leaning toward theories that involved Earth's rapid spin billions of years ago, when each day may have at one time lasted as little as 2 or 3 hours. Decades later in the 1970s, researchers William Hartmann and Donald Davis developed their own models involving collisions of large bodies left over from planetary formation, which could collide with younger planets.

Building on such ideas, other researchers went on to propose similar scenarios between the early Earth and a Mars-sized object. Early in the following decade, the concept eventually claimed its place as the leading lunar-formation process during a landmark conference held in Kona, Hawaii, in 1984.

two large orbs collide, creating an explosion of fire and large rocky objects

Earth's moon is thought to have formed when a Mars-sized object, called Theia, slammed into the proto-Earth more than 4.4 billion years ago, blasting out material that later coalesced into a large satellite as depicted in this artist's illustration. (Image credit: NASA/JPL-Caltech)

Evidence of a planetary-scale collision

The popularity of the giant-impact hypothesis can be attributed to the multiple lines of evidence supporting the impact scenario. For instance, researchers have long recognized the similar stable-isotope ratios between both moon rocks and those from Earth, strongly suggesting a link between their origins.

Additionally, the unusually high angular momentum (or spin) of the Earth-moon system, when compared to observations of other rocky planets, also could be explained as one of the effects of a massive collision.

Further clues can be found in the moon's composition, which reveals a relatively small iron core and lower density. This is significant to astronomers, since a hypothetical giant impact would have seen the suspected Theia protoplanet's metallic core merging with the young Earth's interior — meanwhile, lighter mantle and crust material from both worlds would have become dislodged and blasted into orbit, eventually helping form the moon.

Another important piece of evidence involves the relative depletion of volatile substances (a chemical that easily turns into gas or vapor at room temperatures) in lunar material, which again suggests that it might have been lost during an extremely energetic event, an idea further supported by evidence that the early moon once possessed a substantial magma ocean.

an ocean of magma on the moon

Illustration of the young Earth-Moon system. The Earth had recently formed when it was struck by a protoplanet, called Theia, roughly three times the size of Mars. Debris from the impact went into orbit where it quickly coalesced to form the Moon, probably within just a few thousand years. Initially the Earth and moon were much closer together than they are now, and spinning more quickly. In this depiction, debris from the collision continues to rain down on both worlds. (Image credit: Mark Garlick/Science Photo Library/Getty Images)

What remains unknown?

New research expands on the Theia hypothesis

Still, several significant questions remain, including what precise conditions led to the impact, and how the resulting planetary material evolved into the moon as it appears today.

Recently, a new study by Adeene Denton of Southwest Research Institute and colleagues at the University of Arizona's Lunar and Planetary Laboratory put a new spin on the Theia hypothesis, suggesting that the suspected ancient impact may have been significantly influenced by the heat and physical strength of the two colliding bodies.

The team's findings challenge some long-held views about the giant-impact hypothesis, while lending new support to others. For instance, the team's simulations revealed that while some impacts lead to the creation of a disk of debris that later coalesces into a moon, under other conditions, simulations support the idea that the moon could have been formed in a remarkably short period of time — perhaps within around five hours.

However, one of the primary issues with determining the exact conditions of the giant-impact hypothesis involves the ongoing debate over the moon's age.

"There is a large controversy regarding the age of the moon," said Dr. Erik Asphaug, a planetary science professor at the University of Arizona's Lunar and Planetary Laboratory and one of the new study's co-authors.

A view of the moon in the foreground with a small Earth in the background.

Earth sets over the moon's curved limb in this photo captured by the Artemis II crew during their journey around the far side of the moon. (Image credit: NASA)

In an email to Space, Asphaug explained some of the issues arising from this, since current estimates place the timing of the moon's formation anywhere from around 40 to 120 million years after the formation of the solar system. Therein lies part of the issue, according to Asphaug, who says this timing could have significant implications for models of the Theia impact.

If it had been an earlier collision, Asphaug says this would have involved a hotter Theia due to the greater degree of radiogenic heating; by contrast, a later impact would have meant a cooler and stronger Theia.

"I don't think we know enough yet to say the moon (and by corollary, the Earth) formed this way or that way," Asphaug told Space. "But knowing how temperature affects the result opens up a new dimension for viewing the problem, and that is always helpful because it shifts our frame of reference, like getting out of the car to have a walk around."

A lunar enigma in time and space

For researchers like Asphaug, understanding the moon's formation requires looking at it as more than just an event in space, but also as one in time. Doing so allows comparisons between three different metrics: isotopic decay, temperature-dependent material strength, and the geological record of debris striking other planets — a process through which he believes tighter constraints could be placed on precisely when the moon-forming impact might have occurred.

Adeene Denton, the study's lead author, also emphasized the introduction of the time component her team's research brings to the table, telling Space in an email that the outcome of the moon-forming impact could have depended significantly on the timing of the collision.

"Before, scientists have generally assumed that the outcome of the collision will be the same regardless of when it takes place," Denton wrote. "But now we know that temperature's effect on material properties, which is dictated by how old and/or cold the proto-Earth and Theia might be, alters things substantially."

By connecting impact simulations to data related to the moon's geochemical record, as well as models of early solar system formation, Denton thinks her team's work could help scientists better constrain precisely how and when the moon formed.

The mystery continues

For now, in terms of which possible scenario — an earlier or later collision event — emerges as being the most likely, Denton says it's still difficult to say.

"It depends on which scenarios for solar system formation you favor," Denton told Space.

"I am generally in favor of an earlier formation of the moon, consistent with a rapid planet-building phase in our solar system," Denton said, "but we can't neglect the possibility that the moon formed late."

While much work remains to be done, Denton and Asphaug believe their findings help significantly advance present efforts to resolve some of the questions about the giant-impact hypothesis — a few of which have lingered now for many years.

For Asphaug, however, such lingering questions may simply be part of the scientific process.

"Science has a way of wandering around for a long time until finally it all comes to focus," Asphaug said.

"I believe that will happen, in part thanks to this work, in the coming decade."

Watch Japan launch a bold sample-return mission to Mars moon Phobos today

Editor's note: Japan launched its bold MMX sample-return mission to the Mars moon Phobos on Oct. 19) at 3:41 p.m. EDT (1941 GMT).
Watch a replay of the liftoff and read our launch story here.

Japan will launch an epic mission to Mars today (Oct. 19), and you can watch the action live.

The Martian Moons eXploration (MMX) mission is scheduled to lift off atop an H3 rocket from Japan's Tanegashima Space Center today at 3:41 p.m. EDT (1941 GMT; 4:41 a.m. on Oct. 20 local Japan time).

You can watch it live via the Japan Aerospace Exploration Agency (JAXA). Coverage will begin at 2:45 p.m. EDT (1845 GMT).

illustration of a boxy golden spacecraft orbiting mars, with a small asteroid-looking object to the probe's right

An artist’s concept of JAXA’s MMX spacecraft during its Mars orbit insertion. The Martian moon Phobos, which MMX will explore and sample, is in the background. (Image credit: JAXA)

As its full name suggests, MMX will focus on Mars' two moons, Phobos and Deimos. They're both tiny compared to Earth's own moon; Phobos is just 14 miles (22 kilometers) wide, and Deimos is even smaller, with a diameter of about 8 miles (13 km).

They're also quite mysterious. While astronomers have a pretty clear understanding of our own moon's birth — it coalesced from material blasted into space when a Mars-sized planet slammed into Earth long ago — there's no consensus about Phobos and Deimos' origin story.

The duo "may be the remains of a massive impact on Mars that sent material into orbit around the planet, or they could be ancient asteroids that were captured by Mars' gravity billions of years ago," Tom Statler, MMX program executive and program scientist at NASA Headquarters, said in an Oct. 15 statement. (NASA is a partner on the mission, providing a scientific instrument, a technology demonstration, communication support and funding for American scientists on the MMX team.)

"Having the answer will help illuminate that early era when Earth and the other inner planets may have been acquiring much of their water and organic compounds," Statler added.

MMX will help provide that answer, if all goes according to plan.

The spacecraft will arrive in the Mars system in August 2027, then slip into orbit around Phobos a month later. It will study that moon and Deimos from a distance for about 18 months, then deploy the French-German Idefix rover onto Phobos' surface in early 2029.

The 55-pound (25 kilograms) Idefix "has two main tasks: providing information to prepare for the landing of the main spacecraft to collect samples, and analyzing the composition and texture of Phobos' surface," European Space Agency officials wrote in an MMX mission description.

"The gravity on Phobos is so low that Idefix will only weigh the equivalent of 15 grams [0.5 ounces] on its surface!" they added.

The MMX mothership's Phobos landing will occur in 2030. The spacecraft will grab at least 10 grams (0.4 ounces) of samples from the moon, then head back toward Earth with this extraterrestrial bounty. MMX's return capsule will land here in 2031, after which scientists around the world will scrutinize the Phobos sample for clues about the history and evolution of Mars and our solar system more broadly.

a handful of technicians work with a large spacecraft in a cleanroom

Engineers conduct a thermal vacuum test with JAXA's MMX Mars moon sample-return spacecraft. JAXA posted this image on X on May 15, 2025. (Image credit: JAXA)

MMX was originally supposed to launch in 2024, but issues with the H3 rocket prevented it from doing so. Mars and Earth align properly for interplanetary launches just once every 26 months, so MMX had to wait a while for its next chance.

Japan already has an impressive sample-return track record. The country's Hayabusa mission brought home pieces of the asteroid Itokawa in 2010, for example, and Hayabusa2 did the same with material from the space rock Ryugu a decade later.

Astronomers want your help finding ‘missing’ black holes in the Milky Way

Astronomers estimate that our home galaxy, the Milky Way, has churned out more than 10 million black holes over its 13-billion-year history. Yet so far, they have found only 70.

Now, a group of astronomers in the U.K. is trying to close that vast gap by enlisting the public. Their project, called Black Hole Hunters, is looking for volunteers with a computer and a few spare minutes to sift through troves of data gathered by a NASA space telescope. By flagging recognizable patterns that could point to a "missing" black hole, volunteers can help fast-track a search that would otherwise take years, the team says.

"You'll be narrowing down precisely where we need to point our telescopes next," project co-lead Adam McMaster, an astronomer at the University of Southampton in the U.K., said in a statement, "and you might be the one to discover a black hole."

Cosmic magnifying glasses

Black holes form when massive stars roughly 20 times heavier than our sun run out of fuel and collapse, leaving behind an abyss with gravity so immense that even light cannot escape. While invisible themselves, these cosmic behemoths reveal their presence by bending the light of nearby objects, and the Black Hole Hunters project is searching for one specific manifestation of this effect.

It happens thanks to the fact that massive stars often form in pairs, and a star can sometimes survive the violent supernova explosion that turns its companion into a black hole. When that happens, the two bodies continue to orbit each other. If such a duo aligns just right with Earth, the black hole will periodically pass directly between its companion star and our planet. And when it does, the black hole's gravity acts like a cosmic magnifying glass, bending and magnifying the star's light, causing it to briefly appear brighter to watchful telescopes.

To find these hidden giants, the project relies on data from NASA's Transiting Exoplanet Survey Satellite, or TESS. Although the satellite's primary mission is to hunt for planets beyond our solar system, its method of data collection — tracking tiny, continuous changes in a star's brightness over time — is ideally suited for identifying black hole magnification events, the project description notes.

"It's a simple task with no expertise required," McMaster said in the statement. "We will show volunteers examples of what to look for so all they have to do is recognise the right patterns."

Automated algorithms conduct a preliminary sweep of the TESS data, screening millions of potential stars for the most obvious black hole candidate locations, according to the project description. But, the researchers say, artificial intelligence struggles with the messy realities of the cosmos, such as stellar flares and the natural pulsations of stars that can trick the algorithms into false positives.

The human touch

That makes human volunteers a key part of the search. To keep errors in check, each graph is shown to multiple volunteers, and their answers are combined so that individual mistakes average out, according to the project's website.

"I can search for black holes on my laptop from my bedroom — and could make a real impact on real space science," Grace Clarke, an undergraduate student of physics and astronomy at the University of Southampton who's involved with the project, said in the same statement. "The data's easy to understand — it's just pattern recognition — and you don't need a degree in astronomy to read it."

The crowdsourced shortlist of promising signals lets astronomers aim follow-up observations at specific stars, such as precise measurements of whether a star is being tugged at by an unseen companion. Those measurements take time and are expensive, so a good shortlist helps researchers spend scarce telescope time wisely, the team says.

Since launching on the Zooniverse platform in October 2021, the project has attracted nearly 23,000 volunteers, who have completed more than 12 million classifications, according to its website.

Before turning to TESS, the team ran a similar search using data from SuperWASP, a ground-based survey that, like TESS, monitored stars for signs of planets from 2004 to 2016. Those results are still being analyzed and are expected to be published soon.

The team also plans to widen its search with observations from other instruments, including the European Space Agency's Euclid mission and NASA's recently launched Nancy Grace Roman Space Telescope.

"With potentially thousands of new discoveries, we need all the help we can get," McMaster said in the statement.