Did You Know news

For half a century, scientists have known that Earth's Northern and Southern hemispheres have almost the exact same albedo ‪— the amount of sunlight they reflect back to space. This is true even though the two hemispheres look very different, with the Northern Hemisphere having more land and the Southern Hemisphere having more ocean. Now, researchers have uncovered another surprising symmetry hiding in the data: Earth's Eastern and Western halves appear to reflect the same amount of sunlight as well, they reported in a study published June 3 in the journal Nature. They found that the dividing line lies along a great circle that wraps around the whole planet. It's made up of two longitude lines: the 27 degrees east and 153 degrees west meridians, which stretch from the North to South Pole through Eastern Europe, Turkey, Central Africa, Norway and Alaska."Given that the Earth is approximately spherical, it is unsurprising that one can divide it into two non-overlapping hemispheres that reflect equal amounts of sunlight," the authors write in the paper. But what is surprising, they write, is how closely matched they are. The probability of the hemispheres naturally reflecting sunlight within 0.01 watts per square meter of each other is less than 3%. If the symmetry is a fundamental part of Earth’s climate, this finding could help scientists test and possibly improve global climate models to predict future warming. Secret symmetryWhile the exact mechanism for the northern and southern symmetry has evaded scientists for decades, the study authors said they may have identified a reason behind their discovery. Since the dawn of the space race in the late 1950s, scientists have wanted to figure out Earth's albedo. "That was a really burning question back then," Norman Loeb, an atmospheric scientist who leads NASA's Clouds and the Earth's Radiant Energy System (CERES) project who wasn't involved in the new study, told Live Science. And around a half century ago, they figured it out with satellite imagery.Earth's planetary albedo is about 29%, according to the study. This means that about 0.29 of the solar radiation that hits Earth is reflected back into space. In contrast, a perfect mirror would have an albedo of 1, as it would reflect back 100% of the light that hit it. Other analyses showed that the Northern Hemisphere's albedo was the same as the Southern Hemisphere's, although recent research co-authored by Loeb suggests that the Northern Hemisphere is now absorbing more light than the Southern, likely because of melting snow and ice, declining air pollution, and rising water vapor.This newfound imbalance aside, Zhang, a researcher at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, and colleagues wondered if other symmetry pairs had been overlooked or if they were considered too trivial to investigate, Zhang wrote in a blog. To identify the symmetry, Zhang and his colleagues analyzed 25 years of satellite observations from 2001 to 2025 collected by the CERES program, which uses satellites to measure Earth’s energy budget. Instruments on these satellites measure how much reflected sunlight bounces back into space, as well as how much heat is emitted from Earth Earth's albedo is shaped by many factors; clouds, oceans, snow, ice and land each reflect a different amount of sunlight. This reflection influences Earth's climate, so understanding it is key to an accurate understanding of climate in the future. After running the first analysis, Zhang wrote he was both "absolutely amazed" and skeptical at what he saw, but three features stood out. First the symmetry is unique to the meridian at 27 east longitude. If you shift the line to any other longitude, the symmetry disappears. Second, it's consistent across a 25-year dataset. Lastly, there is "triple symmetry": The two hemispheres contain similar proportions of ice-free ocean, experience similar cloud effects, and reflect similar amounts of sunlight under clear skies. El Niño connectionZhang and his authors hypothesize the East-West symmetry is tied to the El Niño-Southern Oscillation (ENSO), a recurring climate pattern that shifts ocean temperatures and weather around the globe. When they examined the slight changes in the exact longitude of this symmetry, they found correlation with the ENSO record. In the tropics, a giant loop of air called the Walker circulation acts like a big conveyor belt. Warm, moist air rises in the West, travels eastward high in the atmosphere, and then cools and sinks, before blowing back westward at the surface. This circulation acts as the albedo adjustment mechanism, according to the study. The Walker circulation helps drive the difference between El Niño and La Niña, recurring climate patterns, based on weaker or stronger Pacific trade winds, respectively.During La Niña years, the circulation is stronger, causing warmer water and so the Eastern Hemisphere has more clouds, and thus reflects slightly more sunlight. During El Niño, the circulation weakens, warm water spreads across the Pacific and so the Western Hemisphere reflects more. Over many years, the swings average out, helping to keep the long-term east-west symmetry centered near 27 degrees east.The imaginary line runs along the 27 degrees east and 153 degrees west meridians. (Image credit: PeterHermesFurian via Getty Images)Related storiesEl Niño is officially here, and will be among the strongest ever recorded, NOAA announcesAntarctica could warm 1.4 times faster than the rest of the Southern Hemisphere in the coming decades, study findsPollution may fuel depression, anxiety and other mental health problems, emerging research suggests"Nature throws surprises at us, so this is a curious surprise that this one longitude seems to divide the globe up very symmetrically," Loeb said. "It's really interesting that there's this single point longitude at 27 degrees."Since the models are designed to simulate Earth's interactions among the atmosphere, oceans, lands, crust and other parts, the new symmetry offers another way to test if current climate models are accurate. "I think the short-term benefit of this type of discovery is that it's a further test of climate models," Loeb noted.But when the scientists tested how the current models predicted new symmetry, "the models didn't do very well," Loeb said. "They didn't produce this East-West symmetry." This problem may be "contributing to the persistent uncertainty in climate projections," according to the study.How much do you know about our blue planet? Test your terran knowledge with our Earth quiz!

For years, scientists have suspected that, at the molecular level, water is two different liquids ‪—‬ a denser one and a less-dense one ‪—‬ that are constantly switching places. Catching real molecular evidence of this microscopic transformation has been hard. But now, with help from artificial intelligence, researchers say they've finally found it."It's hard to imagine — here is just one water, right?" said Xiao Cheng Zeng, a physical chemist at the City University of Hong Kong and co-author of the new study, told Live Science while holding a water bottle in the air. That puzzle sent him digging through scientific literature, where he found the possible explanation: the two-state hypothesis. "That got my attention. We have literature to talk about it but no evidence." The findings, published June 4 in the journal Nature Physics, could not only prove this long-sought molecular change is real, but also help to explain dozens of water's weird behaviors. Most liquids become denser as they cool, but water behaves differently; it becomes denser until about 4 degrees Celsius, then starts to expand, which is why ice floats. Water also resists temperature changes better than similar liquids and has a viscosity that decreases under certain pressures. Scientists have documented various anomalies related to water and suspect they may be interconnected.The two-state model is an attempt to be that unifying explanation. A 30-year hunchZeng has been studying water since his postdoc days in the late 1990s, when he worked on liquid freezing. The two-state hypothesis itself came onto his radar later — around 2006, when he first encountered it at scientific conferences. But for years, he set it aside as too difficult to tackle directly. That changed roughly around 2016, as researchers began reporting experimental evidence that supercooled water could split into distinct high-density and low-density forms.Around two and a half years ago, Zeng handed the problem to Liwen Li, a postdoctoral researcher in his lab. Rather than repeating the conventional approaches other groups had already struggled with, Li suggested the use of "unsupervised deep learning" — AI trained to spot patterns in data without being told what to look for."So AI [is] forced to learn — to use [its] knowledge to create, to explore," Zeng told Live Science. The team ran massive molecular dynamics simulations, using the GROMACS simulation package. They tracked how hundreds of thousands of water molecules moved and interacted and generated tens of millions of data points."Traditionally, you may need a lot of students to figure that out. ... With computers and AI, it took [Li] maybe a year and a half," Zeng said. Without AI, he estimated, the same analysis might have taken closer to a decade. AI was used to study the molecular composition of water. (Image credit: Vertigo3d via Getty Images)The AI came back with "reaction coordinates" — a small number of variables, distilled out of all that molecular motion, that describe exactly how a water molecule's local arrangement shifts from the denser structure to the looser one and back. They plotted the system's behavior along those coordinates to see the shape of the conversion. That included the number and location of energy barriers, or saddle points, that molecules have to cross to make the switch.Two paths up the mountainThe team found that the path the two structures take to convert into each other changes depending on certain conditions. Most of the time, the switch happens along what the researchers call a "semi-loop" pathway, with a single energy barrier to cross.But near the boundary between high-density and low-density water — the same kind of threshold where ice and liquid water coexist at 32 degrees Fahrenheit (zero degrees Celsius) — the molecules can take a more roundabout "full-loop" path, with three separate barriers instead of one.Zeng compared it to hiking a mountain that's been sliced in half, with a gentle slope on one side and a sheer cliff on the other. Most hikers stick to the slope; that's the semi-loop. But near the boundary where the two halves meet, it's as if the mountain were becoming whole again, letting hikers circle the entire peak. That's the full loop.Zeng and his team are now building a more rigorous machine-learning model to confirm the result. They hope to eventually connect it to properties like density, viscosity and temperature. Related storiesScientists spot water molecules flipping before they split, and it could help them produce cheaper hydrogen fuel New electrochemical method splits water with electricity to produce hydrogen fuel — and cuts energy costs in the process New water battery could last until the 24th century — and it can be safely discarded in the environmentConfirming the structure in real water won't be simple. Zeng said it will likely require new and sensitive experimental techniques — the kind developed by labs like Pacific Northwest National Laboratory, which previously found indirect spectroscopic evidence for water's two-state behavior. "Once we have this ... confirmed by experiment," he said, "this model can be used to [understand] how water interacts with nature." Since most biological and pharmaceutical processes happen in water, a better understanding of water's molecular structure could shed light on how dissolved salts, proteins, and drug molecules interact in solution. "These interactions are vital for injectable drugs and cell function," he noted, but applying this knowledge to practical uses is still a long way off.

China's Einstein Probe has spotted a cosmic explosion from a mysterious source that's unlike anything seen before. The burst was made up of two X-ray flares, about 200 seconds apart, that likely came from the same object. Their behavior is most consistent with powerful cosmic explosions known as gamma ray bursts — except no gamma rays were detected, scientists reported June 13 in the Monthly Notices of the Royal Astronomical Society.Launched into low Earth orbit in 2024 by the Chinese Academy of Sciences in collaboration with the European Space Agency, the Einstein Probe is designed to scan the sky for high-energy X-ray emission events. Those events are usually short-lived, but scientists can use the data to perform detailed follow-up studies with other instruments. The Einstein Probe orbits Earth every 96 minutes and can scan almost the entire night sky about every five hours.On March 5, 2024, the probe captured one such event, called an X-ray transient, from a celestial object scientists named EP240305a. The first flare lasted about two minutes. Roughly 200 seconds later, the probe detected a second flare lasting just over 4 minutes.In the new study, researchers directed several ground- and space-based telescopes toward the area to collect data at X-ray, infrared, optical and radio wavelengths over the weeks that followed. They found that, following the initial burst, the X-rays faded after a few days, while radio emissions slowly petered out over several weeks.To predict what kind of object could emit these bursts, the team compared their data to the expected emissions from several types of X-ray transients. None matched the emission patterns from EP240305a. For example, tidal disruption events, which occur when a supermassive black hole rips apart a passing star, emit light for months or years, while radio emissions from stellar flares fade after a few hours. And other types of X-ray bursts that occur on similar timescales to EP240305a emit no radio signals at all.The most similar type of event that matches EP240305a’s behavior is a gamma ray burst (GRB), the team found. Gamma ray bursts can occur when massive stars die or collide. But without detecting any gamma rays directly, the team can’t yet say that this was the signal's origin. Related storiesRecord-breaking gravitational wave puts Einstein's relativity to its toughest test yet — and proves him right againRadio signal discovered at the center of our galaxy could put Einstein's relativity to the testStrange, 7-hour explosion from deep space is unlike anything scientists have seen — Space photo of the week"In the case of EP240305a, the current data do not allow us to firmly establish a GRB origin, and we therefore conservatively classify it as a gamma-ray-dark GRB-like transient or more broadly an extragalactic fast X-ray transient," the researchers wrote in the study.If the signal was due to a gamma ray burst, the jet of gamma rays may have been pointed away from Earth, or it may have been surrounded by material that hid or reduced the gamma radiation emitted.Collecting data on this and other unusual X-ray transients could help scientists figure out what causes them, the team wrote in the study.

For the first time, archaeologists have analyzed the genetic material of Homo naledi, a mysterious 300,000-year-old relative of modern humans discovered deep in a South African cave system. What they found is unique in human evolution studies: Every skeleton known from the species is female."I think it is fair to say that they surprised us," Lee Berger, a National Geographic explorer-in-residence, told Live Science in an email, but H. naledi "has always been an enigmatic discovery." Since 2013, Berger has headed the Rising Star project, which discovered nearly two dozen skeletons of small-brained, two-legged creatures, which the research team named H. naledi, within a cave system in South Africa's Cradle of Humankind. Research over the past decade has revealed that H. naledi was unusual for having a small brain and upper body, similar to earlier australopithecines like Lucy, but a face, hands and lower limbs that were more human-like. In 2023, the Rising Star team suggested H. naledi may have used fire in the cave, and in 2025, they advanced the controversial claim that H. naledi buried their dead — a complex behavior unexpected for a human relative with such a small brain. But a new study of H. naledi teeth published Wednesday (June 24) in the journal Cell may bolster the team's interpretation of the Rising Star cave as a burial site. An international team of experts studied 20 teeth from H. naledi skeletons using proteomic analysis, a minimally destructive technique that sequences genetic material from ancient proteins. Proteomics is a burgeoning field, especially because these proteins can last longer than DNA. The team focused on amelogenin genes (AMEL), which code for proteins in dental enamel and vary by sex. While the gene variant called AMELX is found in both males and females, another one, AMELY, is found only in biological males. In analyzing the H. naledi teeth, the team found no AMELY proteins but plenty of AMELX ones, suggesting that all of the skeletons were from females. These included the nearly complete skeletons of Neo and DH1, the main representative of the species, both originally assumed to be male. The result is surprising because there are no known ancient human cemeteries or collections of nonhuman primate skeletons that contain only females."The most likely reason for these robust results are, in my opinion, cultural selection after death for burial by sex and perhaps gender," Berger said. "There are many past human societies with sex-specific burial practices," study co-author John Hawks, a paleoanthropologist at the University of Wisconsin-Madison, said in a statement, but the H. naledi skeletons "are older than any known Neanderthal or modern human burial site, and it's remarkable to see that they may all be female."A partial jawbone with teeth from Homo naledi lies was found in the Rising Star cave system. (Image credit: Mathew Berger / Rising Star Program)"An already weird hominin"The discovery that everything we know about H. naledi comes from female skeletons has surprised paleoanthropologists."The bottom line is this is a weird result from an already weird hominin," Elizabeth Sawchuk, curator of human evolution at the Cleveland Museum of Natural History, who was not involved in the study, told Live Science in an email. "The key thing to remember is that failure to detect evidence of AMELY does not mean there are no males in the sample — it just means that none were detected." One possible reason for the lack of this gene in H. naledi skeletons is an AMELY gene deletion that is known to occur very rarely in some modern-human populations and that has been found in one Neanderthal male. If the AMELY gene doesn't exist in this H. naledi group, then the protein profiles of males would look identical to the profiles of females. However, "it's very unlikely that this would be the case among even half of the 20 individuals we studied or for an entire population," study co-author Enrico Cappellini, a paleoproteomics professor at the University of Copenhagen in Denmark, said in the statement. "Either scenario, namely the absence of H. naledi males in the Rising Star cave system or a systematic deletion of their AMELY gene, is fascinating and would have deep implications for a better understanding of the biology and evolution of this species."Studies of H. naledi, a species known from a single site, "continue to yield more questions than answers," Sawchuk said. "As the authors point out, this is a surprising result that requires more investigation."Other hominins in South AfricaA second surprising result in the proteomic analysis was that H. naledi shares a gene variant with Paranthropus robustus, a human relative with a massive face and teeth that lived in South Africa around 1 million to 2 million years ago. Proteomic analysis of four P. robustus skeletons in 2025 proved that limited genetic material could be recovered from ancient human relatives in Africa. The new study has revealed that some members of this species and H. naledi shared a gene variant related to collagen production, which is different from the genes found in modern humans, Neanderthals and Denisovans.While H. naledi and P. robustus inhabited the same general geographic area, it is unclear if they lived there at the same time and overlapped or if they may have had an ancestor-descendant relationship."It is early days for sampling fossil hominins with ancient proteins, and until we build a better, bigger sample, we just don't know" what the shared genetic variant means, Berger said. Building a larger database of ancient proteins from other human relatives that evolved in Africa, such as Australopithecus africanus and Homo erectus, may clarify where H. naledi fits into the picture of human evolution."Key data are missing from H. erectus and A. africanus that would help put this evidence into context," Sawchuk said. "For now, this is another curious finding that bears further investigation."Study lead author Palesa Madupe has pioneered techniques to extract proteins from fossils. (Image credit: Alberto Taurozzi / Rising Star Program)What does sex change?In 2015, Berger and colleagues named the new hominin H. naledi and described what they presumed to be male and female variants of the species based on the skeletons' sizes. In many groups of human relatives and in modern humans, males are physically larger than females, on average. This assumption led the researchers to classify the presumed male individual DH1, discovered in the Dinaledi chamber of the cave, as the main representative of the new species. But a 2024 study was the first to question the assumption that the H. naledi skeletons came from two sexes. In that study, researchers found variation in the teeth of H. naledi that was "so low that the possibility that one sex is represented by few or no individuals in the sample cannot be excluded," they wrote."Our study helps resolve the long-standing mystery of why Homo naledi lacked significant variation," study first author Palesa Madupe, a researcher at the Max Planck Institute for Evolutionary Anthropology in Germany, said in the statement. "It's probably because they could have all belonged to one sex."If the proteomic sex analysis is correct and H. naledi does not have AMELY deletion issues, it means everything we know about the species comes from females. But this doesn't mean interpretations of the species are wrong.RELATED STORIESSouth African fossils may rewrite history of human evolution'I am horrified': Archaeologists are fuming over ancient human relative remains sent to edge of spaceHomo erectus genetic material sequenced for the first time, and it shows 'deep genetic links' with modern humans"The only thing that has changed is that we have never seen a male!" Berger said. "When and if we do, we will have to extend the description to include male sex characters and the likely extension of certain aspects of variation."The researchers hope their study paves the way for more proteomic analyses of human relatives in the future.The new analysis proves that protein analysis of fossils from the Pleistocene (2.58 million years ago to 11,700 years ago) can be done in a minimally destructive way, Madupe said. "This means potentially opening the door to a whole new way of sustainably investigating the differences between sexes in groups of extinct hominins and other animals without causing visible damage to these priceless fossils."What do you know about early humans? Test your knowledge with our human origins quiz!

An isolated population of sperm whales in the Mediterranean Sea are splitting into two distinct groups with different dialects, a new study reveals. This shift has likely been happening for thousands of years, as two groups split from an initial single population.The findings, published Tuesday (June 23) in the journal Proceedings of the Royal Society B: Biological Sciences, are providing a rare insight into the process of different dialects emerging among non-human species.The sperm whales (Physeter macrocephalus) live in small social units of females and young, and they associate with other groups in the same area. They use social vocalizations called codas ‪—‬ shortpatterns of clicks ‪—‬ to communicate. The particular codas they use identify them as being part of the same cultural group.Taylor Hersh, a researcher in the School of Biological Sciences at the University of Bristol in the U.K. and first author of the research, and her colleagues have analyzed codas recorded over almost 20 years in the Mediterranean, where there is a unique population of a few thousand sperm whales, to see if they all use the same dialect.Sperm whales entered the Mediterranean via the Strait of Gibraltar about 20,000 years ago, and they have spread throughout the area. The whales rarely leave the sea ‪—‬ even males, which normally migrate. Other sperm whales don't seem to enter often, either, so the Mediterranean ones are effectively isolated from other populations and are considered an endangered subpopulation."The sperm whales in the Mediterranean are really cool," Hersh told Live Science. "I've always thought of them as the weirdos of the sperm whale world in that they don't leave through the Strait of Gibraltar even though they could. They are unique, and for a long time, they were also thought to be acoustically unique."The thinking was that all the sperm whales in the Mediterranean belonged to the same clan, identified by their use of a single coda 90% of the time. This coda consists of three clicks and then a pause before the fourth and final click ‪—‬ a pattern called the three-plus-one type.But the analysis by Hersh's team of 5,291 codas recorded between 2003 and 2021 revealed that sperm whales living in the eastern Mediterranean around the Hellenic Trench, off Greece, have a slightly different dialect from that used by animals in the western basin around Spain's Balearic Islands. The eastern whales produce a distinct form of the three-plus-one coda. "It's a very similar pattern of clicks, but it's much, much faster," Hersh said.Researchers found distinct dialects between the two populations, with the eastern population producing slower codas. (Image credit: Asociación Tursiops)In some recordings, whales in the eastern Mediterranean produced the slower coda, showing they were familiar with both dialects."The western sperm whales religiously stick to their dialect, but there were four instances of eastern whales using the western dialect," Hersh said. "The question of why is still an open one. Their dialect seems to be a lot more diverse than we expected. They do occasionally make those slow three-plus-one codas, but they make a lot of other coda types, too." Hersh hopes further recordings alongside records that tie individual whales to sounds and events might help elucidate why the whales switch between dialects."It's exciting to see this study showing different populations behaving closely, but also differently," said Gašper Beguš, linguistics lead at Project CETI, a nonprofit organization that aims to translate the communication of sperm whales.The study paints a picture of sperm whales progressively occupying the Mediterranean from west to east, with the dialect of one group gradually changing. "The groups in the east clearly remember the western dialect because they have these 'throwback' days," Hersh said.It's still a mystery how and why these dialects evolved."Every speech is a dialect; the question is how did they arise and why?" said Beguš, who wasn't involved in the new study. He said the historical change in habitat does help to show which dialect came first. "In the Mediterranean, maybe they're forming different groups, so that's why they're trying to distinguish themselves," he told Live Science, giving the parallel of young people who distinguish themselves from previous generations by coming up with new slang.Related storiesWatch sperm whale headbutt another for no apparent reasonSperm whales outwitted 19th-century whalers by sharing evasive tacticsSperm whales drop giant poop bombs to save themselves from orca attack"It's possible that these two groups with repertoires that are very similar but still distinctive could represent a sort of midway phase,” Ellen Jacobs, a marine biologist at Aarhus University in Denmark who wasn't involved in the research, told Live Science via email. "Changes in the rhythm might be a very feasible and meaningful way for coda signals to start to diverge," she said, like the way the English words "How do you do?" got mashed together until they morphed into "howdy."The timescale on which a sperm whale dialect develops is uncertain, but it's likely a slow process, according to Hersh. "It's probably happening on the scale of hundreds and thousands of years, because sperm whales can live into their 60s and 70s. And this study is looking over 19 years of data, and that's just a snapshot of one animal's life," Hersh said.This means the eastern whale dialect was conceivably emerging in the Mediterranean Sea as famous human civilizations were speaking different languages on the surrounding lands, including when the ancient Greeks and Romans were rising and then falling."Maybe if we could leave them for another 10,000 years, we would come back to find the completely separated dialects of clans," Jacobs said.

A deep-space telescope on a grand mission to make the largest-ever 3D map of the universe just peered into the star-filled heart of the Milky Way. In the new observations, shared Wednesday (June 24), the Euclid space telescope imaged the center of the Milky Way in extraordinary detail, showing off more than 60 million stars crowded in the galaxy's center. The shiny new image from the European Space Agency (ESA) spacecraft will help astronomers confirm newfound exoplanets and use changes in starlight to measure those planets' masses as they orbit their parent stars, according to ESA scientists.The image was taken in 26 cumulative hours in March 2025, across nine pointings of the telescope's visible-light camera toward the galaxy's center, also called the galactic bulge. Each viewpoint captured a slice of sky larger than the full moon. In a statement, ESA praised the performance of Euclid under challenging conditions. "Designed to observe billions of faraway galaxies, the space telescope's visible-light camera is sensitive enough to tell apart individual stars in our super-crowded galactic bulge, without being blinded," agency officials wrote.The mosaic image will help NASA's Nancy Grace Roman Telescope with its upcoming planet-hunting mission, after that observatory launches aboard a SpaceX Falcon Heavy rocket from NASA's Kennedy Space Center in Florida no earlier than Aug. 30. One way the Roman telescope will search for new worlds is through microlensing, the same technique that can be used to examine exoplanets in the new Euclid image. Microlensing happens when one star passes in front of another from the perspective of an observer. The gravity of the closer-up star briefly bends and magnifies the light of the star behind it, allowing possibly unseen planets to pop up near that star.An image of the Milky Way as seen from Earth, showing two zooms of Euclid's target area. (Image credit: ESA/Euclid/Euclid Consortium/NASA, CFHT, ESA/Gaia/DPAC,image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay))"During the last 20 years, almost 300 exoplanets have been discovered using this technique, all with ground-based telescopes and all towards the centre of our galaxy," Jean-Philippe Beaulieu, who initiated the Euclid galactic bulge survey and co-led the Euclid Consortium's exoplanet working group, said in the ESA statement."This image from Euclid includes 51 known planetary systems ‪—‬ and it will assist in studying many more that will be found," added Beaulieu, who holds positions at the Paris Institute of Astrophysics and the University of Tasmania in Australia.An infographic showing how Euclid sees across the Milky Way, into the galaxy's central bulge. The bottom panels illustrate the diversity of structures in Euclid's field of view. (Image credit: ESA/Euclid/Euclid Consortium/NASA, CFHT, image processing by J.-C. Cuillandre and E. Bertin (CEA Paris-Saclay); Milky Way artist impressions: ESA/Gaia/DPAC, Stefan Payne-Wardenaar))A cosmic time capsuleEuclid's observing window was too short to find a microlensing event, which requires more than 20 days of examining one star to watch for a planet's orbit and associated changes in the star's light. But Euclid's work did allow astronomers to measure already-known planets. And once newer planets are confirmed by other telescopes, the image will let astronomers look back to confirm those newfound worlds' masses.Related storiesEuclid telescope spots rare 'Einstein ring' hiding near Earth — and an ancient, unnamed galaxy behind itEuclid telescope reveals 1st section of largest-ever 3D map of the universe — and there's still 99% to goHubble and Euclid capture the final act of a dying star — and it's glorious"In 24 hours, Euclid has already captured the stars involved in all the future microlensing events that the Roman space telescope will detect, but before the stars and planets involved have aligned," Natalia Rektsini, a postdoctoral fellow at the Paris Institute of Astrophysics who led the release of Euclid's galactic bulge survey data, explained in the statement. "Anyone who detects a microlensing event in the same region, for example with Roman, will be able from now on to use Euclid data as a time reference in the past and see how the stars looked before they overlapped," she added. "Since Euclid can clearly separate individual stars, one can then measure how fast they move over time, and use that information to confirm the existence of a planet and determine its mass. This would not be possible with data from one point in time."How well do you know our home galaxy? Find out with our Milky Way quiz!

The patient: A 61-year-old man in Japan The symptoms: The man visited a hospital because two months earlier, some foods and beverages began to taste extremely unpleasant to him. Over time, more foods had become difficult for him to stomach. Sour and salty flavors were the first to trigger disgust. Oily foods were next, followed by fresh vegetables, cold water and juice, warm water and, finally, sweets.The man ate less due to the taste aversions, and he unintentionally lost a few pounds. He told doctors at the hospital that he felt lethargic, they wrote in a report of the case.What happened next: The patient, who was a physician himself, reported that eight years ago, he had been diagnosed with bipolar disorder. For the prior three years, he had been managing the condition with lithium, a mood stabilizer commonly used to treat bipolar disorder. He was taking a prescribed dosage of 800 milligrams per day and historically hadn't had any unusual side effects. (This is slightly higher than the typical dose recommended for chronic management of bipolar disorder, but that said, doctors may tweak patients' doses based on their individual needs.)The diagnosis: Doctors performed bloodwork and found that the level of lithium in the patient's blood was 1.28 milliequivalents per liter (mEq/L). Safe levels of lithium are between 0.6 and 1.2 mEq/L; any higher than that can cause a condition called lithium toxicity, which can be fatal if untreated. When the doctors checked the man's medical records, they found that prior to the onset of his symptoms, the levels of lithium in his blood were between 0.4 and 0.9 mEq/L. In the report, the authors did not investigate the cause of the toxicity, nor did they hypothesize as to why lithium was accumulating in the patient's blood. The treatment: The doctors told the man to stop taking lithium, and they instead prescribed another mood-stabilizing drug, called valproate. As the lithium levels in his blood dropped, the patient's energy returned and the foods and beverages that previously disgusted him recovered their normal flavors. Notably, this happened in the reverse order that their flavors had changed. At a follow-up visit one year later, the man was still taking valproate and his symptoms of fatigue and taste changes had not returned.Other dilemmasViral infection caused woman not to recognize her own fatherBrain scans following a man's hospital visit for leg weakness revealed a surprising findingMan who donated his body after death had rare 'triple penis'What makes the case unique: Although they're uncommon, side effects of lithium use can include confusion, increased thirst, frequent urination, irregular or slow heartbeat, tiredness and weight gain. Rarer side effects include dizziness, headaches, vision problems and heat loss in the arms and legs. Lithium toxicity, also known as lithium intoxication, is known to increase the risk of these adverse symptoms. Changes in a patient's sense of taste while taking lithium have been recorded in just a handful of reports dating to the 1970s and 1980s. One patient lost the ability to taste salt, while another "noticed a strange and unpleasant taste associated with butter and celery." Nevertheless, "it has not been generally known that lithium can lose or change taste in some patients," the case report authors wrote. Based on their findings, they suggested that in the future, taste loss or changes in taste perception should be flagged as a potential indicator of mild lithium intoxication. This article is for informational purposes only and is not meant to offer medical advice.

Perhaps the biggest existential question we’ve learned how to ask is one of the most straightforward ones of all: the question of, as you look around at our world, galaxy, and cosmos, where it all ultimately comes from. Sure, we can look back — farther through space and further back in time — and learn about our cosmic past. We can learn about the evolution of chemical elements and the birth of planets, we can learn about the cosmic star-formation history and the growth of galaxies and large-scale structure, and we can learn about the hot, dense, uniform state that preceded everything we observe today. We can learn how the ingredients within our Universe, including normal matter, dark matter, dark energy, photons, and neutrinos, shaped the expansion history of our Universe, and allowed minuscule seeds of structure to grow into today’s star-and-galaxy-rich cosmic web. We can trace our cosmic history back not only to the hot Big Bang, but to an inflationary state that preceded it and set up the Big Bang with the right properties to reproduce and create the Universe as we observe it all throughout cosmic history. But despite all of these successes, we only have access to information from the final 10-32 seconds or so prior to inflation’s end. Questions about its total duration, about its origin (if it had one), and about a pre-existing state that gave rise to inflation remain unanswered. Even though it’s only suggestion and speculation, there’s a set of thoughts about our ultimate cosmic origins that, when you put them together, point in a very stringy direction. Here’s why even those who are the most skeptical of string theory can’t dismiss its importance when it comes to the very beginning of our Universe. The central idea of string theory is that all the quanta we know of are described by tiny strings that vibrate in various ways on minuscule scales: far below what’s ever been probed. String theory is an attempt at a framework for quantum gravity, and arguably the only viable candidate for finding out what’s real in the Universe on trans-Planckian scales. Credit: Berkeley Center for Cosmological Physics Simply by looking back through space, we can see the Universe as it was further back in time. When we take stock of what we find back then, some fascinating features include: a cosmic microwave background that was hotter in temperature, a Universe that was less clumped and clustered, with smaller, lower-mass galaxies and galaxy clusters, with populations primarily of younger, bluer, and less chemically enriched stars, where the Universe was denser, and where the expansion rate was greater in the past, all of which point to the same early picture of our cosmic origins: the hot Big Bang. By hypothesizing an early hot, dense, nearly uniform, rapidly expanding, matter-and-radiation filled state, we can make sense of the evolution to the cold, sparse, heavily clumped and structure-rich, slowly expanding, dark energy and dark matter-dominated Universe that we observe today. However, this picture itself, of the hot Big Bang, doesn’t explain everything that we observe about the Universe. It doesn’t explain why the energy density and the expansion rate seem to balance one another so perfectly: the flatness problem. It doesn’t explain why different regions of ultra-distant space, including in opposite directions from one another, have the same temperature as one another: the horizon problem. It doesn’t explain why there are no leftover high-energy relics, as one would expect, from an arbitrarily hot, dense, early state: the monopole problem. And it doesn’t explain what the seeds of our large-scale cosmic structure would need to be, or provide a mechanism for creating them. In the top panel, our modern Universe has the same properties (including temperature) everywhere because they originated from a region possessing the same properties. In the middle panel, the space that could have had any arbitrary curvature is inflated to the point where we cannot observe any curvature today, solving the flatness problem. And in the bottom panel, pre-existing high-energy relics are inflated away, providing a solution to the high-energy relic problem. This is how inflation solves the three great puzzles that the Big Bang cannot account for on its own. Credit: E. Siegel/Beyond the Galaxy These motivating factors are what led scientists to concoct and develop the idea of cosmic inflation during the late 1970s and early 1980s. According to inflation, the Universe didn’t begin from an arbitrarily hot, dense state, where all of the matter and energy in the Universe was compressed into a single point — a singularity — at an event that marked the birth of space and time. Instead, if you rewound the clock back to early enough times, to a hot-and-dense state that was still of a finite size, volume, and temperature, you’d find: That instead of being filled with matter-and-radiation, the Universe was filled with field energy, or energy inherent to space itself. That instead of expanding and cooling, the Universe was expanding at a constant, relentless rate: doubling in size again and again with each small interval of time that elapsed. That the Universe’s entropy remained constant during this phase, but due to the relentless expansion, its entropy density plummeted. That no matter what the conditions of the Universe were prior to inflation, inflation had now stretched it flat, and imbued it with the same temperatures and densities everywhere. And that because there are still quantum fields in the Universe, as inflation goes on and on over time, those fluctuating quantum fields get stretched across space to all scales, leading to a spectrum of “seed fluctuations” that will translate into energy density (and temperature) fluctuations when inflation comes to an end. That last fact is a key prediction of inflation, as it allows us to build inflationary models that possess specific fluctuation spectra: spectra that then translate into CMB fluctuations and features in the large-scale structure of the Universe that we can, in the here-and-now, go out, test, and measure. The fluctuations in the cosmic microwave background, as measured by COBE (on large scales), WMAP (on intermediate scales), and Planck (on small scales), are all consistent with not only arising from a (slightly tilted, but almost-perfectly) scale-invariant set of quantum fluctuations, but of being so low in magnitude that they could not possibly have arisen from an arbitrarily hot, dense state. The horizontal line represents the initial spectrum of fluctuations (from inflation), while the wiggly one represents how gravity and radiation/matter interactions have shaped the expanding Universe in the early stages. Credit: NASA/WMAP science team Inflation can help explain not only the flatness, horizon, and monopole problems, but it makes additional, explicit predictions that have now been verified: that the nature of the seed fluctuations would be entirely adiabatic (and not isocurvature), and that there would be seed fluctuations that existed on super-horizon scales, which remains some of the strongest observational evidence that favors and validates cosmic inflation. Additionally, the models of inflation that work to describe our Universe are the ones that: produce a maximum temperature, for the hot Big Bang, that’s at least a factor of several thousand smaller than the Planck temperature, produce a spectrum of almost scale-invariant fluctuations, but with fluctuations that are about 3% greater on large cosmic scales rather than small ones, produce only very small-magnitude gravitational wave (tensor) fluctuations, and that lead to the magnitude of initial temperature/density fluctuations being at about the few-parts-in-100,000 level, with respect to the average cosmic temperature/density. From that initial set of seed fluctuations — a spectrum of fluctuations predicted and produced by inflation — normal and dark matter gravitate, radiation pushes back on the normal matter, and we get temperature imperfections that imprint themselves in the cosmic microwave background, and then later, correlations between galaxies in the resultant large-scale structure of the Universe. A detailed look at the Universe reveals that it s made of matter and not antimatter, that dark matter and dark energy are required, and that we don t know the origin of any of these mysteries. However, the fluctuations in the CMB, the formation and correlations between large-scale structure, and modern observations of gravitational lensing all point toward the same picture. Credit: Chris Blake & Sam Moorfield That’s the short version of the story of cosmic inflation and how it leads to the Universe we observe today. No alternative to inflation has reproduced these successes, while inflation has made many predictions that differed from the hot Big Bang without inflation, all of which have fallen in favor of inflation wherever they’ve been tested. It’s one of the most spectacular theoretical and observational successes of a theory in the late 20th and early 21st centuries. And yet, inflation doesn’t tell us everything. Because of its very nature — the fact that, during that early period of inflation, it caused empty space to double again and again, relentlessly, with each tiny fraction-of-a-second that elapses — the only imprints we have of inflation that exist within our observable Universe (i.e., inside of our cosmic horizon) were created during the final 10-32 seconds of inflation. In other words, anything that happened prior to inflation’s final moments, including: anything that led to a change in inflation’s behavior, anything that caused the onset of inflation in the first place or triggered the initiation of an inflationary state, or anything that pre-existed in the Universe prior to those final moments of inflation, has forever been erased from the portion of our Universe that’s even in principle observable to us. During cosmological inflation, the space contained in the inflationary region grows exponentially, doubling in all three dimensions with each tiny fraction-of-a-second that passes. Where inflation ends, a hot Big Bang ensues. But due to quantum effects, each region where a Big Bang occurs will be surrounded by more inflating, exponentially expanding space, ensuring that no two regions where hot Big Bangs occur ever collide, intersect, or overlap. Credit: Kavli IMPU Why is that? Because it was wiped out by the very nature of inflation itself. All we have to resort to, in this regime, are mathematical and theoretical arguments, as there is nothing observable or measurable we can point to in order to shed further light on the issue of our cosmic origins before those final moments of inflation. We are capable of learning some lessons from those considerations, however. We learn that inflationary spacetimes are past-timelike-incomplete, which teaches us that the inflationary state could not have been eternal to the past, but rather was preceded by a prior, non-inflationary, and possibly singular (but also possibly non-singular) state. But what was that state? It had to have been a high-energy state, otherwise there’s no way to get the high energy densities that we experience at the start of the hot Big Bang. It may be related to the Bunch-Davies vacuum, which corresponds to a particle-free state in an exponentially expanding Universe. It could correspond to a state of grand unification, where not only were the electromagnetic and weak nuclear forces unified, but the strong nuclear force joined them as well. It’s also possible that there were more dimensions to our Universe during whatever pre-inflationary state our Universe possessed. There’s an important paper from around that key time — right at the border between the late 1970s and the early 1980s — that contained within it a profound and powerful realization. This animation shows three expanding dimensions of space emerging in the Kasner metric from a higher-dimensional spacetime with one contracting dimension. Even though the three expanding dimensions begin anisotropic, as they grow, the portion of the Universe that’s observable will become indistinguishable from flat, homogeneous, and the same in all directions. Credit: Lantonov/Wikimedia Commons That paper, written by Alan Chodos and Steve Detweiler, is simply titled, “Where has the fifth dimension gone?” In the paper, they show that if you start from a five-dimensional Universe, where four of those dimensions are spatial and the other one is a time dimension, and you allow that Universe to be in an empty, vacuum solution state (described by the Kasner metric), then as one spatial dimension shrinks, the other three dimensions grow. What you wind up with, then, is a Universe that’s: isotropic (the same in all directions), homogeneous (the same in all locations), expanding, with three spatial dimensions and one time dimension, and described by the same solution to Einstein’s general relativity that physicists have used for over 100 years to describe our Universe: the Friedmann–Lemaître–Robertson–Walker metric. Think about all of this together, now. We live in a (with three space and one time) four-dimensional Universe. It’s isotropic and homogeneous today, and filled with matter and radiation, after arising from a prior state that was represented by an empty, rapidly and relentlessly expanding past, where quantum effects were important and stretched to cosmic scales. If the energies were great enough, forces could have unified. If there were extra dimensions, their shrinking could provide an explanation for why the three dimensions we have today expanded in the past, and continue to expand today. And if you consider the possibility that gravity was unified along with the other forces — what’s known as a theory of everything — there’s only one known candidate theory that allows you to embed both general relativity and the entire Standard Model fully within it: string (and/or superstring) theory, requiring 10 dimensions in its unbroken, fully restored state. One of the most popular efforts toward a Theory of Everything is string theory, where the Lie Group E8 x E8 is shown here: one realization of 10-dimensional superstring theory. The number of particles, fields, interactions, and dimensions that must be removed to keep the predictions of this overarching framework consistent with what we observe in our Universe is overwhelming, and represents more than 95% of the theory’s general predictions. Credit: Claudio Rocchini & Peter McMullen/Wikimedia Commons This leads to the big thought that sometimes keeps me, as well as other cosmologists who think about the ultimate origins of our Universe, up at night. When you start with a spacetime of a given number of dimensions, there are only a few Lie groups (a certain type of mathematical structure) that can cover them, where every Lie group corresponds to a spectrum of particles, as well as a set of forces and interactions between those particles. For superstring theory in its unbroken state, that 10-dimensional spacetime can be covered by a Lie group like SO(32) or double-covered by E8 ⊗ E8. Both of these groups contain not just the Standard Model and general relativity within them, but a whole host of other things that we know our Universe doesn’t actually possess. In order to get down to just four-dimensional spacetime, however — the spacetime that we observe ourselves to inhabit here in the modern, post-Big Bang Universe — we have to make six of those dimensions go away: a process known as compactification. While some deride compactification as a hand-wavy process, from a mathematical perspective, there are only a few options. 10 dimensions can be broken down into: 5 + 5 dimensions, 6 + 4 dimensions, 7 + 3 dimensions, 8 + 2 dimensions, or 9 + 1 dimensions, with larger numbers of dimensions having the ability to be broken down further. If you examine the “6 + 4” option in detail, however, as having four dimensions is particularly relevant to our Universe, it turns out that while there are many ways for the “6” part to be compactified, there’s only one unique mathematical state to describe the four-dimensional part. If you go from 10 dimensions down to four, the “four” part that emerges is unique. This particle chart shows the pattern of charges W (weak isospin), W’ (weaker isospin), g3 and g8 (strong force charges), and B (baryon minus lepton number) within the SO(10) grand unified theory. The pattern has been rotated to show its embedding within the larger E6 group. Credit: Cjean42/Wikimedia Commons Sure, there are still more particles and more interactions than we have from the plain old Standard Model; the Lie group that (maximally) covers this four-dimensional spacetime is E6, which allows for grand unification to occur, but which contains the entire Standard Model within it: SU(3) ⊗ SU(2) ⊗ U(1). The theory of gravity that describes this spacetime is almost equivalent to Einstein’s general relativity; once we come down to four spatial dimensions, it’s equivalent to a scalar-tensor theory of gravity known as Brans-Dicke gravity. All we have to do is remove the scalar term (or take the Brans-Dicke coupling term, ω, to infinity), and we recover Einstein’s standard general relativity. Sure, there are still puzzles related to this idea: where are the extra particles and interactions predicted by this larger Lie group, why are there no flavor-changing neutral currents seen in particle physics experiments, why haven’t we observed proton decay if the interactions are allowable, and what mechanism effectively “hides” these extra theoretical components that don’t appear to manifest in nature, but the possibility that this idea relates to the origin of our Universe cannot be so easily ignored. If our Universe did indeed emerge from a 10-dimensional string theory, then breaking those ten dimensions down to our four could not only give us our theory of gravity and our Standard Model of particles and interactions, but the process of compactification could lead to a state, for the remaining spatial dimensions, that looks a whole lot like the scenario of cosmic inflation appears to us in our cosmic past. The quantum fluctuations inherent to space, stretched across the Universe during cosmic inflation, gave rise to the density fluctuations imprinted in the cosmic microwave background, which in turn gave rise to the stars, galaxies, and other large-scale structures in the Universe today. This is the best picture we have of how the entire Universe behaves, where inflation precedes and sets up the Big Bang. Unfortunately, we can only access the information contained inside our cosmic horizon, which is all part of the same fraction of one region where inflation ended some 13.8 billion years ago. Credit: E. Siegel; ESA/Planck and the DOE/NASA/NSF Interagency Task Force on CMB research Today, we have a Universe that’s governed by two sets of laws that we understand — general relativity as our theory of gravity, with the Standard Model plus quantum field theory providing the particle content and describing the other three forces — plus a slew of unsolved mysteries, including cosmic inflation, dark matter, and dark energy. Although there are many models for all of these unknowns, it remains possible that they’re all related not only to one another, but to the cosmic knowns as well, and (super)string theory is the one framework that is actually capable of bringing them all together. Of course, none of these problems or puzzles, individually, requires string theory of any variety in order to solve them. Each one can be solved by a much simpler solution. Inflation can be modeled as a single scalar field. Dark matter can be modeled as a single species of cold, collisionless particle. Dark energy could simply be a cosmological constant with a positive, finite, non-zero value. And beyond that, the remaining mysteries that are often discussed today (like the Hubble tension or evolving dark energy) could be mere phantasms: spurious results that won’t require any new physics once better observational data arrives. Still, there’s that nagging thought that persists: what if everything we don’t understand today, or that we can’t explain today, ultimately has the same, single solution that dates back to an epoch in cosmic history beyond the limits of what’s observably imprinted on our Universe? That’s the stringy thought that sometimes keeps inflationary cosmologists up at night. Now that you understand that line of thinking, perhaps you’ll wonder about that same possibility yourself. This article One stringy thought causes inflationary cosmologists to lose sleep is featured on Big Think.

Earth's oldest known impact crater formed when a meteorite slammed into what is now Australia about 3 billion years ago ‪—‬ 470 million years later than scientists previously claimed, a new study suggests.The impact crater, known as the North Pole Dome crater, is located in Western Australia's Pilbara region, which is home to some of the planet's oldest rocks. It remains a record-breaking structure, beating the world's next-oldest known meteorite impact crater — the Yarrabubba impact structure, also in Western Australia — by roughly 800 million years."While the site had previously been identified as an ancient impact structure, its exact age remained uncertain," study first author Chris Kirkland, a professor in the School of Earth and Planetary Sciences at Curtin University in Australia, said in a statement. "The impact left a 'mineral clock' behind. By dating minerals that were remade or newly grown in the damaged rocks, we can now pin down when this extraordinary event happened."In a study published last year, Kirkland and his colleagues said they had "unequivocal evidence" that the North Pole Dome crater was 3.47 billion years old, based on an analysis of cone-shaped chunks of rock known as "shatter cones" that form when the shock waves from a meteorite impact propagate downward.However, a study published four months later in the journal Science Advances called the other team's results "inaccurate," arguing that the impact occurred no earlier than 2.7 billion years ago.For the new study, Kirkland and his colleagues used advanced mineral dating techniques to estimate the ages of zircon, apatite, calcite and muscovite in shatter cones from the North Pole Dome crater. The researchers analyzed two samples of shatter-cone-bearing rocks, as well as a shocked quartz vein — a sheet-like deposit that typically forms when superhot, mineral-rich water circulates in the cracks between shocked rocks.Researchers analyzed zircon and other minerals in North Pole Dome rocks. (Image credit: Curtin University)"The key evidence comes from zircon, a tiny but extraordinarily resilient mineral that can keep geological time for billions of years," Kirkland said. "Some zircons at North Pole Dome have unusual branching, skeletal shapes. We interpret these as impact-modified crystals, formed when older zircon was disrupted, partly recrystallised, and in places regrown during the intense heating caused by the impact."RELATED STORIESIncomplete remains of world's 'youngest' impact crater spotted lurking in Chinese forest — Earth from spaceGiant meteor impact may have triggered massive Grand Canyon landslide 56,000 years agoWilkes Land crater: The giant hole in East Antarctica's gravitational field likely caused by a meteoriteThe age recorded in zircon was the same as that locked inside apatite minerals, giving the researchers confidence that the impact occurred a little more than 3 billion years ago. The younger shatter cones in the Science Advances study may have formed subsequently due to tectonic and thermal activity, the team wrote in the new paper, which was published Tuesday (June 23) in the journal Geology."Ancient impact 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 signals," Kirkland said. "The new age places the North Pole Dome structure as Earth's oldest known impact crater and the only recognised example from the Archean eon [4 billion to 2.5 billion years ago], a time when the planet's earliest continents were forming."Planet Earth quiz: What do you know about our planet's most amazing features?

Using drugs to induce a hypothermia-like state may slow stroke-related brain damage, according to a new study involving lab animals and human patients.The study used two existing drugs: the antipsychotic chlorpromazine and the sedative promethazine, called "C+P" when they're used together. This drug combo induced hypothermia and protected brain tissue in mouse and monkey models of stroke. Additionally, an infusion of C+P was safe in an early trial including 32 human stroke patients, causing no notable side effects. However, no significant improvements in stroke outcomes were reported in a paper describing the results, which was published June 17 in the journal Science Translational Medicine.More research is needed to determine what benefits C+P treatment may offer stroke patients. But the research sheds new light on the metabolic dynamics believed to be responsible for hypothermia's therapeutic effects, said Dr. Eric Landsness, an assistant professor of neurology at the Washington University School of Medicine in St. Louis who was not involved in the work. "What's exciting about this study is that it's clear that it's not just the hypothermia, but it's the hypometabolism," said Landsness, who reviewed the paper before it was published.Brain freeze?The researchers tested C+P as a therapy for acute ischemic stroke, in which blood flow to the brain is blocked. Ischemic strokes are the most common form of stroke, accounting for over 85% of cases; "acute ischemic stroke" specifically refers to the medical emergency brought about by a sudden loss of blood flow to the brain and corresponding loss of neurologic function.When blood flow is restored through a therapy called reperfusion treatment, "you can get significant injury from a lot of processes that were set in motion during the ischemia," said Dr. Patrick Lyden, a professor of physiology and neuroscience, neurology, and neurosurgery at the University of Southern California Keck School of Medicine who was not involved in the study.To protect brain tissue from this double whammy of ischemia and reperfusion injury, some researchers have tried to harness hypothermia, which is "one of the most powerful ways of protecting the brain that we've ever studied in lab animals," Lyden told Live Science. "It's the standard by which all other brain protectants are measured."In hypothermia, body temperature drops below 95 degrees Fahrenheit (35 degrees Celsius). Under normal circumstances, this can be very dangerous because the cold can slow down the heart and nervous system to the point that the body's cardiac and respiratory systems fail.But one of the biggest theories for why hypothermia works in a therapeutic context is that it slows down our metabolism, similar to what's seen in animals during hibernation, Lyden said. "Because the metabolism is slowed, the death process in the brain is also slowed down."Therapeutic hypothermia can protect the human brain following cardiac arrest, and it is also sometimes used to treat newborns with hypoxic ischemic encephalopathy, an injury that blocks blood and oxygen to the brain around the time of birth. However, studies of hypothermia in adult stroke patients have been less successful, Lyden said.Acute ischemic strokes damage brain tissue by cutting off blood flow to part of the organ, but reintroducing blood to the brain can also trigger injury. (Image credit: Douglas Sacha via Getty Images)The C+P approach may be a more effective way to slow metabolism in stroke patients, the researchers hypothesized. In previous experiments, C+P reduced neuroinflammation in rodent models of stroke, possibly through changes in metabolic activity independent of hypothermia.In the new study, the treatment was compared with two other methods of reducing core temperature in mice: a different drug, called adenosine 5'-monophosphate, and surface cooling using cold water and ice packs. While all three approaches induced hypothermia in the mice, only C+P treatment reduced their overall oxygen consumption and energy expenditure, two important indicators of slowed metabolism.The paper highlights metabolism as more than a mere secondary effect of hypothermia, Landsness said; it's a process worth studying in its own right.In mice, C+P treatment reduced the burning of sugar by the brain and brown fat, which burns fuel to generate heat. The treatment was also associated with less brain tissue damage and lactate accumulation, which can drive cell death, after stroke. These effects were also observed in rhesus monkeys treated with C+P. According to the small safety trial with humans, the metabolic effects of C+P appear to extend to people. The researchers measured lower levels of metabolism-associated proteins in the blood of patients who received the highest dose of the treatment tested. These were also the only patients to experience a significant decrease in body temperature at four hours after treatment, although their temperatures never dipped into true hypothermia. (Temperatures did fall that dramatically in the mice and monkeys.)Related stories'We're starting to find a lot more weirdness': These strange animals can control their body heatHumans may have untapped 'superpowers' from genes related to hibernation, scientists claimScientists may be able to put Mars-bound astronauts into 'suspended animation' using sound waves, mouse study suggestsIn people, C+P infusion did not reduce the degree of brain damage seen 72 hours after treatment, nor did it affect the participants' ability to perform daily activities without assistance after 90 days. Alongside the C+P treatment, the patients had also received standard reperfusion therapies. The study authors, based at Capital Medical University in Beijing, did not respond to Live Science's request for comment. In their paper, they wrote that future trials could potentially establish the protective value of the C+P treatment in stroke. In the current study, C+P did not trigger notable side effects in humans, but Lyden worried that the medications may still pose a risk of worrying effects. The two drugs could potentially interact in ways that cause symptoms like muscle spasms, seizures or changes in heart rhythm, for example. For that reason, it may be best to find different drugs that still slow metabolism but don't come with those risks, Lyden suggested. To find an alternative to the C+P regimen, researchers will need a better sense of how the drugs exert their effects. The new paper "happened to fall upon a drug [combo] that happens to induce hypothermia and hypometabolism, but we don't necessarily know why," Landsness said. His lab is studying the neural circuits involved in hypothermia and hypometabolism, which could reveal new therapeutic targets.This article is for informational purposes only and is not meant to offer medical advice.See how much you know about the most complex organ in the human body with our brain quiz!

A massive wave of warm water is making its way across the Pacific Ocean as the newly declared El Niño gets into full swing, satellite images show.The band, called a Kelvin wave, marks a swell of higher-than-average sea levels that stretches hundreds of miles along the equator. The anomaly is caused by warmer waters linked to El Niño — the warm phase of a natural climate pattern whose current iteration could become one of the strongest ever recorded.The Sentinel-6 Michael Freilich satellite captured the deviations from average sea surface height on June 8. Red areas indicate higher sea surfaces than usual, while blue areas mark areas with lower surface heights. Developed and launched in 2020 by NASA and the European Space Agency and operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), Sentinel-6 Michael Freilich measures changes in sea surface height down to fractions of an inch every 10 days.The data complements measurements of sea surface temperature that have shown Pacific waters warming at unpreceded rates over the past several months, leading scientists to declare the start of a new El Niño on June 11. When ocean water warms, it expands and takes up more space. That translates to an increase in the height of the water relative to the satellite and the center of Earth, which is then picked up by the satellite's sensitive equipment. At some points along the equator, sea surfaces are now more than 6 inches (15 centimeters) higher than usual.Kelvin waves like this one form when winds in the western Pacific near the equator weaken and temporarily reverse, blowing from west to east instead of east to west. That lets warm water gradually build up in the east, deepening the layer of warm surface waters and preventing colder waters from rising from below. The wave has now reached the western coast of South America.NASA had already observed a few other Kelvin waves this year, suggesting an El Niño event was soon to follow. In January, Sentinel-6 Michael Freilich detected one near Micronesia that dissipated around mid-February. Another emerged in March and elevated sea levels near Peru by mid-May.Related storiesEl Niño is officially here, and will be among the strongest ever recorded, NOAA announcesComing El Niño will be the strongest ever recorded, new forecast predicts'The biggest El Niño event since the 1870s': 'Super' El Niño is now the most likely scenario by the end of this year ‪—‬ and the humanitarian cost could be hugeChanges in sea surface temperature or height can alter atmospheric circulation patterns and affect the weather. El Niño often increases rainfall in the southwestern U.S., Colombia, Peru and Ecuador, while rainfall in the western Pacific tends to decrease. The most recent El Niño, which lasted from June 2023 to April 2024, boosted global mean temperatures that made 2024 the hottest year on record and the first to breach the 1.5 degrees Celsius (2.7 degrees Fahrenheit) warming limit — a guardrail set by the Paris Agreement beyond which the effects of climate change become more and more catastrophic. The June 8 conditions in the western Pacific were similar to those that occurred 1997 during a particularly strong El Niño, according to a statement from NASA. 2026 has seen fewer Kelvin waves so far than 1997, but this year’s El Niño is still ramping up."For now, it looks like it's going to be a big one — more so than I would have said last week — but we still need more observations to know what's going to happen," Severine Fournier, a sea level researcher at NASA’s Jet Propulsion Lab, said in the statement.How much do you know about our blue planet? Test your terran knowledge with our Earth quiz!