Category: 7. Science

Since we know of no better thinking machine than the human brain, one of the main objectives of machine learning is to build an artificial copy of it. But while some very advanced machine learning algorithms have been developed in recent years, none of them are actually very much like the brain. By comparison, they are very slow on the uptake, easily fooled, and terribly inefficient. So why not just clone a brain and declare that artificial general intelligence has been achieved already? Surely we have more than enough GPUs to simulate all of the neurons.

That is much easier said than done. The problem is that we do not understand how the brain works well enough yet. A team led by researchers at the University of Sheffield wanted to fill in this gap in knowledge, but given that the human brain is extremely complex, they decided to start a bit smaller. They created a computational model of the sesame seed-sized brain of a bee. By using this model to better understand the function of bee brains, we can glean some insights that will help us to improve our algorithms today, and perhaps ultimately get us to a better model of the human brain.

In the course of their work, the team found that bees do not just passively observe their environment. Rather, they actively shape what they see by moving their heads, bodies, and eyes in strategic ways. These flight movements create distinctive electrical patterns in their tiny brains, making it easier to extract meaningful information from the visual chaos of the natural world. And somehow, this tiny system can solve difficult visual discrimination tasks, such as recognizing human faces, with far fewer neurons than any artificial system in existence today.

The researchers used this insight to construct a highly efficient, biologically inspired digital brain. They then tested it with a range of challenges, including a pattern recognition task where the model had to distinguish a plus sign from a multiplication sign. Just like real bees, the model improved its accuracy dramatically when it mimicked natural bee scanning behavior.

This suggests that movement is more than just about getting around — it is also an integral part of how animals learn. Rather than brute-force number crunching, intelligent systems might benefit more from smart sampling: moving to see better, to think better. The bee model’s neurons gradually adapted to the motion patterns of the visual input, forming efficient, sparse codes that required minimal energy. Unlike standard AI models, this one used non-associative learning in which it refined itself without needing constant reinforcement.

Furthermore, the researchers found that active scanning helps encode information in a compressed and efficient form in the bee’s lobula, a visual processing center. When paired with additional neural structures that mirror the mushroom body (which is used for associative learning), the system performed well across a wide range of visual tasks.

Ultimately, this study might offer us a roadmap to smarter, leaner AI. If we want machines to learn with the efficiency and elegance of natural brains, we may need to start thinking not just about what they see, but how they move.

The Full Moon is just days away now, but if you want to know what’s going on with the moon tonight, keep reading because we have all the info you need.

The moon changes each night, well, from our perspective it does anyway. This is because of the lunar cycle, a recurring series of eight unique phases of the moon’s visibility. The whole cycle takes about 29.5 days (according to NASA), and these different phases happen as the Sun lights up different parts of the moon whilst it orbits Earth. The moon is always there, but what we see on Earth changes depending on how much it is lit up.

See what’s happening with the moon tonight, July 5.

What is today’s moon phase?

As of Saturday, July 5, the moon phase is Waxing Gibbous. According to NASA’s Daily Moon Observation, 75% of the moon will be lit up and visible to us on Earth.

This is day 10 of the lunar cycle, and we’re only one phase away from the Full Moon. So, with so much of the moon lit up, there are plenty of geological features for us to spot, both with the naked eye and with aids.

Tonight, there is plenty to see with the naked eye, the most notable being the Mare Vaporum, the Copernicus Crater, and the Tycho Crater. With binoculars, you can add the Alps Mountains, Archimedes Crater, and the Alphonsus Crater to your list.

If you’re one of the lucky ones with a telescope, you’ve got a great night of moon gazing ahead of you, with additional viewings of the Linne Crater, Apollo 12, and the Rupes Altai.

When is the next full moon?

This month’s full moon will take place on July 10. The last full moon was on June 11.

What are moon phases?

Moon phases are caused by the 29.5-day cycle of the moon’s orbit, which changes the angles between the Sun, Moon, and Earth. Moon phases are how the moon looks from Earth as it goes around us. We always see the same side of the moon, but how much of it is lit up by the Sun changes depending on where it is in its orbit. This is how we get full moons, half moons, and moons that appear completely invisible. There are eight main moon phases, and they follow a repeating cycle:

New Moon – The moon is between Earth and the sun, so the side we see is dark (in other words, it’s invisible to the eye).

Waxing Crescent – A small sliver of light appears on the right side (Northern Hemisphere).

First Quarter – Half of the moon is lit on the right side. It looks like a half-moon.

Waxing Gibbous – More than half is lit up, but it’s not quite full yet.

Full Moon – The whole face of the moon is illuminated and fully visible.

Waning Gibbous – The moon starts losing light on the right side.

Last Quarter (or Third Quarter) – Another half-moon, but now the left side is lit.

Waning Crescent – A thin sliver of light remains on the left side before going dark again.

The soundtrack of the Age of Dinosaurs remains a mystery. The T-rex’s roars and the screams of velociraptors we see in the movies — such as the fourth installment of Jurassic World, which opened last week — are purely the invention of sound engineers seeking to shock viewers. These supposed dinosaur sounds have permeated the popular imagination, while for years scientists could do little more than speculate. Since the vocal apparatus of animals is composed of soft parts that almost never fossilize, until very recently, the sounds of dinosaurs could only be imagined based on the canals these animals had for perceiving sounds and on certain crests and ornaments on their skulls that could serve as sound chambers. But all that is changing.

The 70 million-year-old Parasaurolophus tubicen might have sounded like a ship’s horn or an Australian didgeridoo thanks to its distinctive cranial ornamentation, as shown in a scientific recreation at the New Mexico Museum of Natural History and Science. In 1995, paleontologists at the museum recovered a fossil of the hadrosaur with a massive crest nearly a meter long protruding from the back of its head.

Like a prehistoric wind instrument, inside this unique structure there were three pairs of hollow tubes running from the nose to the top of the crest, which researchers scanned in minute detail using a CT scan. After two years of work, the result was computer simulations of how the organ would resonate if air were blown through it, digitally reconstructed with the help of computer scientists. “I would describe the sound as otherworldly. It sent chills through my spine,” Tom Williamson, one of those paleontologists, recently told the BBC.

No one knows for sure what the enormous diversity of dinosaurs that existed throughout the Mesozoic sounded like. The soundscape would have been different at each of the three stages of the more than 180 million years that spanned it, but science has made some attempts. Based on the shape of the inner ears and other cranial cavities, scientists have developed theories about what this group of extinct reptiles might have sounded like.

If the purpose was to communicate and warn of danger, the dinosaurs’ hearing would have had to be subordinate to that function; their small auditory structures would have perceived low frequencies, just as modern crocodiles do. Animals are supposed to perceive the types of sounds they themselves can produce. No screams or roars. It’s more likely that most large dinosaurs emitted long-wavelength, low sounds capable of traveling long distances and shaking the earth. A low, amplified hiss, something like a beastly ancestor of the Italian opera singer Cesare Siepi, considered one of the best lyric basses of the 20th century.

However, the imagination must stretch in another direction, one that lessens the terror of the sounds of some of these prehistoric beasts. Until recently, it was believed that high-pitched calls and high shortwave frequencies were reserved for birds, but in 2023, a discovery emerged from the sands of the Gobi Desert (Mongolia) that changed everything.

It was a fossilized larynx of the ankylosaur Pinacosaurus grangeri — a three-ton, quadrupedal, herbivorous armored vehicle almost two meters in height and about five meters in length — which suggested that birdsong could have also come from wingless animals. “This is the first discovery of a vocal organ from non-avian dinosaurs in the long history of research on them. Interestingly, the larynx of Pinacosaurus is similar to that of modern birds, so it probably used it to modify the sound like birds, rather than the vocalization typical of reptiles. Therefore, we can say that Pinacosaurus basically sounded similar to birds,” says in an email the Japanese paleontologist Junki Yoshida, first author of the discovery, which was published in the journal Nature.

The larynx is made of cartilage, a type of soft tissue that is easily disintegrated by microorganisms and environmental erosion, so its natural preservation over millions of years is exceptional. Therefore, paleontology has turned to other resources to try to reconstruct something as intangible as sound. “Dinosaur sound communication had been studied only through the inner ear of the fossil skull, but not through the vocal organ itself,” explains Yoshida, openly proud of his work. “Therefore, my discovery of the larynx represents a completely new and more direct approach to studying dinosaur sound communication.”

Dawn with the song of a dinosaur

On the other side of sound — and the world — the Argentine paleontologist Ariana Paulina Carabajal, an expert in sensory biology at the National Scientific and Technical Research Council (CONICET), is working on cranial structures to elucidate how these extinct animals saw, heard, and moved to do what all living beings do: survive each day. “What do animals use sound for? Basically, to communicate with each other and to warn of danger, but very little is known about the emission side.”

The conclusions derived from the larynx of Pinacosaurus coincide with those drawn by Paulina Carabajal in Canada, Mongolia and Turkey, when studying a part of the inner ear of dinosaurs from the same family. “I studied one of the two ankylosaurs in which the lagena — a fundamental structure for hearing — was preserved, and when I reconstructed them, they were among the largest I’d found so far. Very long, much longer than in other dinosaurs.”

She continues: “In general, their lagenas are the same size as those of a modern crocodile; they don’t change much, but ankylosaurs have wider lagenas. So, we think they would have slightly increased their range of sound perception. Always at low frequencies because all dinosaurs tended to hear low frequencies. Now, in conjunction with the Gobi discovery, it makes sense. We understand that for some reason they heard a little differently than other dinosaurs. They had some specialization for vocalization. It’s interesting because it changes the interpretation of the entire group of ankylosaurs and opens the possibility of asking: what other dinosaurs could have had a similar development?”

It’s tempting to get excited about the implications of the discovery. Taking a bit of a risk, the scientist believes that, since they were desirable prey for large carnivores, it’s not unreasonable to think that these animals were capable of producing high-pitched sounds imperceptible to their predators. But she acknowledges that reality isn’t always as linear as that reasoning, and therefore, there are other aspects to consider.

Paleontologist Fedrico Agnolín, a researcher at CONICET and the Azara Foundation, worked 10 years ago on another discovery linked to prehistoric sound: an exceptionally preserved syrinx from a species of duck extinct 70 million years ago was the first direct evidence of the typical vocal apparatus of birds that coexisted with the last dinosaurs. In light of Yoshida’s discovery, he proposes a bold reconstruction. “That dinosaur’s vocal repertoire is somewhere between that of songbirds and parrots. It’s not that we’re thinking it sounded like an eagle, no. Maybe it was like a thrush that got up in the morning and started singing.”

For him, we must give free rein to our imagination. “The problem is that we have a whole wealth of previous research that we can’t get out of our heads. So, we keep imagining a Tyrannosaurus rex as a gigantic reptile, even though its relatives, whose fossils have preserved their skin, show that they were covered in protofeathers, something similar to hair. The whole body is covered in hair, let’s suppose, but we’re still unable to imagine a T. rex like that.”

More cautiously, Paulina Carabajal sets limits on creativity. “What shouldn’t be interpreted directly from Yoshida’s work is that when he emitted sounds like a bird, he had a song. It wouldn’t be like the beautiful songs birds make, but rather a rattling sound related to the way air passed through the larynx.”

This is a different instrument from that of birds, which, on the other hand, have a syrinx, a unique organ that allows them to produce those songs so appreciated by humans. “Reptiles have folds of tissue that protrude — move — into the space where the air comes out, and when they move, they generate sounds, hisses, but most reptiles don’t vocalize. Making a sound is one thing, and vocalization itself is another.” That’s why the case of the Pinacosaurus from the Gobi Desert is so surprising. Its discoverers emphasize that it and its mates could have vocalized.

The larynx of this ankylosaur is composed of two parts like that of any reptile, but with the peculiarity that between these two pieces there was mobility, which would have allowed it to control the air that entered and exited, producing sounds similar to those of some birds.

Re-evaluating many fossils

The tongue of reptiles is not mobile like that of mammals. Since it is attached to the lower part of the jaw, its movement is very limited, and only the tip remains free, preventing it from manipulating food. What is interesting about Pinacosaurus, according to Paulina Carabajal, is that “very large hyoid cartilages that support the tongue — essential for swallowing, breathing, and producing sounds — were also found. Therefore, the authors propose that this tongue was much more mobile than in other dinosaurs, perhaps allowing it to manipulate food a little when grabbing it.”

For Agnolín, surprises could emerge in specific cases. “We have to reevaluate many remains. Dinosaurs are found with some neck pieces whose exact nature is unknown. We have to see if they are syrinxes or similar structures.” Erosive factors, above all, limit certainties. “The syrinx is composed of several ossified cartilages that wrap around each other and form a kind of small drum. When the animal dies, this falls off, falls apart, and rots. So, if you find a small piece of a syrinx drum, which must be 2 millimeters in size, you wouldn’t recognize it,” the Argentine scientist laments.

Studies like his own and that of Pinacosaurus, however, encourage us to review the deposits in search of those fragments that were not identified at the time to assess the possibility that they might be sound tracks. This is something he has already done, and he regrets not having found any matches. Agnolin suspects that in many cases, human bias will also have to be overcome. “Perhaps there are some researchers who deny that this is a syrinx and will talk about other structures. All of this takes time and is part of the scientific debate, which is eternal.”

The consensus among paleontologists is that, with these insights and ongoing technological advances, solving the mystery of the dinosaurs’ sounds is closer than ever. Reconstructing the soundtrack of the Mesozoic is only a matter of time.

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In the past fifteen years, five missions have returned samples of extraterrestrial material to Earth for analysis. These included missions that rendezvoused with Near Earth Asteroids (NEAs), like the Hayabusa 1 and 2 and the OSIRIS-REx missions, and the Chang’e-5 and
-6 missions, which brought back samples from the far side of the Moon. In the coming years,
China plans to return samples from 469219 Kamoʻoalewa with its Tianwen-2 mission. With all the extraterrestrial materials being returned to Earth for analysis, one could argue that we are entering a “golden age of sample-return missions.”

As a result, efforts are underway to create facilities where scientists can safely contain, curate, and analyze these samples. At the University of Leicester’s Leicester Space Park, scientists are working on a Double-Walled Isolator (DWI) to store and analyze extraterrestrial materials safely. This could include future samples returned from Mars, which NASA and other space agencies are planning to do through crewed or robotic missions expected to happen during the late 2020s or early 2030s.

The DWI is essentially a miniature version of a clean room and is designed to keep materials at a high level of containment and cleanliness. This is ensured by an inert gas environment and state-of-the-art robotics (an arm and other manipulator technologies) to move samples between containment, an optical microscope, and a Raman spectrometer. These measures minimize interactions between scientists, prevent cross-contamination, and preserve sample integrity so scientists can obtain accurate results when conducting analyses.

As Andrew Cheney, DWI QM Project Manager at Space Park Leicester, said in a University of Leicester press release:

The SRR is a major milestone for the project that shows that we’ve fully understood the customer need, and translated that into a set of requirements to proceed with confidence into the design phase. Generating a good set of requirements is arguably the hardest part of any project and takes a lot of research, analysis, and industry expertise.

Now [that] we have that agreed baseline, we look forward to the design phase and the many, many challenges it will bring for this unique piece of equipment. We have a relatively compressed period now to push a concept through to detail design and manufacture. The dedicated qualification phase will involve simulating end-to-end curatorial and scientific processing of martian analogue samples at SPL.

This €5 million ($5.89 million) project was initially developed for the NASA/ESA Mars Sample Return (MSR) mission and builds on previous work where the Leicester team created a design for a prototype DWI. In the new phase, the Leicester team will be collaborating with experts from several British universities and institutes, including the Open University, the Francis Crick Institute, Imperial College London, and the Natural History Museum. They’ve also partnered with Extract Technologies, a UK-based manufacturer of advanced isolator technologies, to provide a detailed design for the main isolator and manufacture it. Said John Holt, DWI QM Principal Investigator at Space Park Leicester:

Whether or not an astronaut or a robotic spacecraft brings samples back from Mars, the Double Walled Isolator (DWI) is a key UK technology that enables planetary scientists to scrutinise returned rocks to understand the Martian environment and if there is microscopic evidence for life on the red planet. The milestone review [SRR] we have just conducted carefully looked at the complex needs of scientists to ensure we design an ultra-clean system that allows them to handle the precious samples and use a wide range of analytical techniques to unlock the secrets within each piece of rock.

The facility recently passed its System Requirements Review (SSR) with the European Space Agency (ESA) and is now proceeding to the Design and Qualification phase. Currently, there are four missions in the works to return samples from Mars, including NASA’s proposed crewed missions to Mars, China’s Tianwen-3, JAXA’s Martian Moons eXploration (MMX), and Russia’s Mars-Grunt mission.

Further Reading: University of Leicester

BERLIN   –   Stone Age humans living by a lake in what’s now Germany systematically processed animal carcasses for fatty nutrients — essentially running what scientists describe as a “fat factory” to boil bones on a vast scale, according to new research. Archaeologists uncovered the factory by analyzing some 120,000 bone fragments and 16,000 flint tools unearthed over several years at a site known as Neumark-Nord, south of the city of Halle, they reported in a study published Wednesday in the journal Science Advances. Excavators found the artifacts alongside evidence of fire use. The researchers believe that Neanderthals, an extinct species of human known to have lived in that area as far back as 125,000 years ago, smashed the marrow-rich bones into fragments with stone hammers, then boiled them for several hours to extract the fat, which floats to the surface and can be skimmed off upon cooling. Since this feat would have involved planning hunts, transporting and storing carcasses beyond immediate food needs, and rendering the fat in an area designated specially for the task, the finding helps paint a picture of the group’s organization, strategy and deeply honed survival skills. “This attitude that Neanderthals were dumb — this is another data point that proves otherwise,” said Wil Roebroeks, study coauthor and professor of Paleolithic archaeology at Leiden University in the Netherlands. A string of archaeological discoveries in recent decades have showed that Neanderthals were smarter than their original brutish stereotype might suggest. The ancient humans lived across Eurasia and disappeared 40,000 years ago, and previous studies have found they made yarn and glue, engraved bones and cave walls, and assembled jewelry from eagle talons. Details in the new research suggest that Neanderthals may have been unexpectedly sophisticated in their approach to nutrition, too.

The Neanderthals living at the German site over a 300-year period also clearly understood the nutritional value of the bone grease they produced, according to the study. A small amount of fat is an essential part of a healthy, balanced diet. The substance was even more essential for hunter-gatherers, such as Neanderthals, who likely depended heavily on animal foods. A diet dominated by lean meat and deficient in fatty acids can lead to a debilitating and sometimes lethal form of malnutrition, in which the capacity of liver enzymes to break down the protein and get rid of excess nitrogen is impaired, the researchers noted in their paper. Known today as protein poisoning, the condition earned a reputation among early European explorers of North America as “rabbit poisoning” or “mal de caribou.”

Fruits and vegetables are often sprayed with fungicides to keep mold at bay. However, new research suggests one of these chemicals could be quietly harming insects that are critical to healthy ecosystems and could lead to an insect apocalypse.

According to a study from Macquarie University, one of the world’s most widely used fungicides, chlorothalonil, drastically reduces insect fertility. It does so even at the lowest levels commonly found on produce.

During testing and research, scientists exposed fruit flies to real-world doses of the chemical and found that their egg production dropped by over a third. The effect wasn’t something that happened slowly over time, either. Instead, it was immediate and significant, the statement says, affecting both male and female fertility. And this isn’t an effect like when researchers got fruit flies hooked on cocaine, either. This is actually life threatening for the population.

And while that might sound useful, especially considering how annoying fruit flies can be when they settle down a plant in your home, it’s a big deal for more than just flies. Insects like bees, flies, and other pollinators are crucial for growing the food we eat. If their populations decline, it could disrupt pollination and harm crops in the long run. This study is just the latest in a growing list of research documenting steep drops in insect populations around the world, which some scientists have heralded as an impending insect apocalypse.

What’s especially concerning is that this fungicide isn’t just used when there’s a risk of infection. It’s often applied preventatively, when no disease is present in the crops. While it’s true that chlorothalonil is banned in the European Union, it remains widely used in places like Australia, where it’s applied to everything from vineyards to farms that harvest berries.

Despite its popularity, chlorothalonil hasn’t been studied under the microscope all that much. Fewer than 25 published studies have explored its impact on insects, so this new study could be a massive piece of a case against the future usage of this chemical. This also points to a major gap in how we evaluate the environmental effects of common pesticides we rely on.

The researchers behind the study suggest rethinking how often chlorothalonil is applied. By spacing out treatments, farmers could give insect populations time to recover between sprays. While not the best outcome by any means, it would at least mitigate some of the damage we’re doing to the insect populations, though how long it will take for them to recover between sprays would need to be determined, too.

For the first time, an international team of scientists has experimentally simulated spontaneous symmetry breaking (SSB) at zero temperature using a superconducting quantum processor. This achievement, which was accomplished with over 80% fidelity, represents a milestone for quantum computing and condensed matter physics.

The system began in a classical antiferromagnetic state, in which particles have spins that alternate between one direction and the opposite direction. It then evolved into a ferromagnetic quantum state, in which all particles have spins that point in the same direction and establish quantum correlations.

“The system began with a flip-flop configuration of alternating spins and evolved spontaneously, reconfiguring itself with spins aligned in the same direction. This phase transition is due to symmetry breaking,” summarizes Alan Santos, a physicist currently researching at the Institute of Fundamental Physics of the Spanish National Research Council (CSIC) and co-organizer of the theoretical team involved in the study. At the time the work was developed, Santos was a FAPESP postdoctoral fellow at the Department of Physics of the Federal University of São Carlos (UFSCar) in the state of São Paulo, Brazil.

The research was conducted by scientists from the Southern University of Science and Technology in Shenzhen, China; Aarhus University in Aarhus, Denmark; and UFSCar. The results were published in the journal Nature Communications.

“The crucial point was simulating dynamics at zero temperature. There had already been previous studies on this type of transition, but always at temperatures other than zero. What we showed was that, by setting the temperature to zero, it’s possible to observe symmetry breaking even in local particle interactions, between first neighbors,” says Santos.

It is worth remembering that absolute zero cannot be physically achieved because it is equivalent to the total immobility of a material system. The researchers simulated what would happen to the system at zero temperature through quantum computing. The experiment used a quantum circuit of seven qubits arranged in a configuration that allows interactions only between immediate neighbors. They applied an algorithm to simulate adiabatic evolution at zero temperature. “We designed the circuit, and the experimenters in China implemented it physically,” says Santos.

The phase transition was identified using correlation functions and Rényi entropy, which revealed the formation of ordered patterns and quantum entanglement. Entanglement is one of the most important and distinctive properties of quantum mechanics. It refers to a situation in which two sets of particles are correlated such that the state of one particle instantly determines the state of another, even if they are separated by large distances. Introduced by Hungarian mathematician Alfréd Rényi (1921-1970) in the 1960s, Rényi entropy is used to quantify the degree of entanglement and its distribution among parts of a quantum system. It allows us to measure the degree to which the subsystems are entangled.

Santos points out that entanglement and superposition are two central features of quantum computing: “Superposition allows a system to exist in multiple states simultaneously, called quantum parallelism. Entanglement is a type of correlation that cannot be reproduced on classical computers. To give you an intuitive idea, imagine you have a bunch of keys and need to find out which one opens the lock. A classical computer tests the keys one by one. A quantum computer, on the other hand, can test several of them at the same time, which speeds up processing,” compares Santos.

In practical terms, the difference between a classical computer and a quantum computer comes down to performance. Both can solve the same mathematically formulable problems in theory. The question is how long it takes them to do so. Some calculations, such as factoring huge numbers into two prime numbers, would take classical computers millions of years but can be performed much faster on quantum computers.

It would be counterintuitive to use a classical computer to simulate quantum systems. Sometimes it is an impossible task. The study in question showed that it is possible to use quantum computing resources for such simulations. The experiment was conducted at the Southern University of Science and Technology in Shenzhen. Shenzhen is currently one of the most advanced scientific, technological, and industrial hubs on the planet. Selected in 1980 as China’s first “special economic zone,” the city has evolved from a fishing village of about 30,000 people into a metropolis of over 17 million. It is home to giant companies that lead the global market.

The implementation used superconducting qubits based on aluminum and niobium alloys that operate at temperatures around one millikelvin. “The advantage of superconducting qubits is their scalability. It’s technically possible to build chips with hundreds of them,” says Santos.

The concept of symmetry breaking is present in all areas of physics. All of physics is structured around symmetries and their breaking. “Symmetry gives us the laws of conservation. Symmetry breaking allows complex structures to emerge,” summarizes Santos.

Impact craters exist on every continent on Earth. While many have eroded away or been buried by geologic activity, some remain visible from the ground and from above. This week, we revisit stories featuring some of our most captivating satellite images of impact sites around the planet. The images and text on this page were excerpted from content originally published on April 22, 2024.

In the Kutch district of northwest India, a vast desert where salt is harvested in colorful rectangular ponds stretches to the Arabian Sea. In a neighboring grassland, a less conspicuous circular feature has attracted curiosity in recent decades. Scientists in India had suspected, but not confirmed, that an object from outer space made this mark on the landscape. Now, a geochemical analysis of the structure has revealed it contains the characteristic signatures of a meteorite impact.

Impact craters on our planet are a relative rarity; fewer than 200 structures from around the world are confirmed in the Earth Impact Database. The number of craters is so modest in part because many of the meteorites that survive the trip through Earth’s atmosphere ultimately splash down into water. Of the meteorites that do fall on land, evidence of their impact may be erased by forces such as wind, water, and plate tectonics.

The footprint of the newly studied Luna impact crater—named for its proximity to a village of the same name—is visible in this image, acquired by the OLI (Operational Land Imager) on the Landsat 8 satellite on February 24, 2024. The crater measures approximately 1.8 kilometers (1.1 miles) across, and its outer rim rises about 6 meters (20 feet) above the crater floor.

The Luna structure is situated in India’s Gujarat state in a grassland called the Banni Plains. The Great Rann of Kutch, an expansive white salt desert, lies just to the north. Parts of these low-lying areas are submerged for much of the year, and the Luna crater often contains water. Researchers took advantage of a dry period in May 2022 to collect samples from throughout the structure.

In the rocks and sediments, scientists detected several minerals that are uncommon in natural settings on Earth. These rare minerals form under the extremely high temperatures and pressures generated when a meteorite hits the ground. The researchers also measured anomalously high concentrations of the rare element iridium, consistent with findings at other impact craters.

Based on the radiocarbon dating of plant remnants contained in silt at the site, the team determined the impact occurred about 6,900 years ago. The crater is near the remains of an ancient Harappan settlement, but it is uncertain whether the impact predates the arrival of humans.

NASA Earth Observatory image by Michala Garrison, using Landsat data from the U.S. Geological Survey. Story by Lindsey Doermann.