Latest news with #EddieSchwieterman
Yahoo
26-04-2025
- Science
- Yahoo
Did the James Webb telescope really discover aliens? Here's the truth about K2-18b.
When you buy through links on our articles, Future and its syndication partners may earn a commission. The trendiest planet in the universe right now is K2-18b, a potentially habitable world swirling around a small, red star in the constellation Leo. Located 124 light-years from Earth, the mysterious planet will never host human visitors — but a recent glimpse with the James Webb Space Telescope (JWST) hints that alien life may already thrive there in a vast, warm ocean. In a University of Cambridge-led study published April 17, scientists using JWST reported the detection of possible signs of life in the alien planet's atmosphere, offering what a Cambridge statement called the "most promising" evidence yet of life beyond Earth. However, in the week since the study's publication, a growing number of scientists are already pushing back on this big claim. "The statistical significance of the detection is marginal," Eddie Schwieterman, an assistant professor of astrobiology at the University of California, Riverside who was not involved in the research, told Live Science in an email. "There are some reasons to be skeptical." "It's almost certainly not life," Tessa Fisher, an astrobiologist at the University of Arizona who was not involved in the research, told So what did JWST actually find on K2-18b, and how close are we to solving the ultimate mystery of space? Here's everything you need to know. Unlike optical telescopes such as Hubble, JWST cannot image the surfaces of distant planets directly; instead, its infrared instruments hunt for chemical signs of life — or biosignatures — in planetary atmospheres by mapping how starlight is absorbed or reemitted by molecules in those atmospheres. The resulting graphs of light, called spectra, can reveal the composition of that planet's atmosphere, providing clues about its surface conditions. Related: 32 alien planets that really exist In the new Cambridge-led study, scientists using JWST's Mid-Infrared Instrument (MIRI) peered into K2-18b's atmosphere to detect traces of two sulfur-based molecules called dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) — compounds that are known to be produced only by microscopic life-forms like phytoplankton on Earth. If DMS can be produced by some natural mechanism, scientists currently don't know about it, and will have to run extensive tests to uncover it. The findings add to earlier observations made by the same team using two different JWST instruments in 2023, which also reported possible traces of DMS in the planet's atmosphere. While the Cambridge team admitted in the statement that they are "deeply sceptical" of their own results, the same release also trumpeted these detections as the "most promising" evidence yet of life beyond Earth, painting a picture of an oceanic planet that could be "teeming with life." (Other studies have argued that K2-18b's ocean may, in fact, be made of magma.) Nikku Madhusudhan, lead author of both Cambridge studies, stressed that no actual life has been detected on K2-18b yet. "That's not what we're claiming," Madhusudhan, a professor of astrophysics at Cambridge, told Live Science. "But in the best-case scenario, it's the potential for life." The team's DMS detection reached the three-sigma level of statistical significance, meaning there is a 0.3% probability that the signals occurred by chance. However, this still falls far short of the required five-sigma level that denotes a statistically significant scientific discovery. Responding to criticism that the team may have overstated their study's significance, Madhusudhan said it's in the public interest to know how this research is progressing. "This is the taxpayer paying us, and they have a right to enjoy the process," Madhusudhan added. "If we're sending a robot to Mars, we're not waiting until it goes and finds life to celebrate the act of sending it. We announced that we are sending robots to Mars, and we're excited about the possibility. This is the equivalent of that." For now, the public has little more than the Cambridge team's study to go on. The complete set of MIRI data on which the team based their discovery will become publicly available April 27, according to NPR, at which point outside researchers can begin to comb through it and formulate peer-reviewed responses. In the meantime, various researchers have already attempted to re-create the findings using their own data models and have come up short. In January, a team of scientists independently analyzed K2-18b's atmosphere using the same JWST instruments used in the 2023 study. The team found "no statistically significant or reliable evidence" of DMS on K2-18b, the researchers wrote in a paper published to the preprint server arXiv. More recently, on April 22, University of Oxford astrophysicist Jake Taylor reanalyzed the JWST spectra shared in the new Cambridge study, using a simple data model that's routinely utilized in exoplanet studies. Taylor's analysis, also published to arXiv, found no traces of DMS, either. "There is no strong evidence for detected spectral features in K2-18b's MIRI transmission spectrum," Taylor wrote. Looking only at the Cambridge team's study, Schwieterman also saw cause for hesitation in proclaiming that biosignatures exist on K2-18b. "When DMS interacts with ultraviolet light from the star, it splits apart into components that reform into other molecules like ethane (C2H6) and ethylene (C2H4)," Schwieterman said. "The paper does not report the detection of these molecules, which is puzzling because you'd expect these gases to appear together." Everyone, including the Cambridge team, agrees that more observations of K2-18b are necessary to bring clarity to this puzzle. This means researchers will have to request more time with JWST to observe the alien planet as it swoops in front of its star. Luckily, this is a near-monthly occurrence, with K2-18b completing a transit of its star every 33 days. Budgeting more time to watch these transits should be "trivial" for the telescope, Madhusudhan said. RELATED STORIES —What messages have we sent to aliens? —If life can exist in your stomach, it can exist on Mars. Here's what it might look like. —'Perhaps it's only a matter of time': Intelligent life may be much more likely than first thought, new model suggests "One transit is eight hours, roughly," Madhusudhan added. "You only need about 16 to 24 hours of JWST time. To give you a sense of scale, JWST observes thousands of hours every year." If additional observations can increase the statistical significance of the team's DMS detection, the next step will be to prove that some unknown natural process isn't producing the molecule instead, Schwieterman said. This will take rigorous experimentation and some creative thinking here on Earth. Finally, scientists will need to look at planets that are similar to K2-18b to see if DMS is a common signature around the cosmos.
Yahoo
01-04-2025
- Science
- Yahoo
James Webb telescope could find signs of life on alien 'hycean' ocean worlds
When you buy through links on our articles, Future and its syndication partners may earn a commission. Hycean worlds, which are a possible kind of exoplanet with deep oceans surrounded by a thick envelope of hydrogen, could provide the best chance for the James Webb Space Telescope (JWST) to detect biosignatures, according to a new study. Those potential signs of life are a group of chemicals called methyl halides, which on Earth are produced by some bacteria and ocean algae. "Unlike an Earth-like planet, where atmospheric noise and telescope limitations make it difficult to detect biosignatures, hycean planets offer a much clearer signal," said Eddie Schwieterman, who is an astrobiologist at the University of California, Riverside, in a statement. For now, the existence of hycean planets remains hypothetical. Their name is a portmanteau of "hydrogen" and "ocean," first coined in 2021 by planetary scientist Nikku Madhusudhan of the University of Cambridge. Related: 'Hycean' exoplanets may not be able to support life after all Hycean planets are expected to orbit red dwarf stars, and the best candidate for a hycean world is the planet K2-18b. This exoplanet, which is categorized as a "sub-Neptune" world, orbits in the habitable zone of a red dwarf star 124 light-years from Earth in the constellation of Leo, the Lion. The Hubble Space Telescope discovered water vapor in K2-18b's atmosphere in 2019, and JWST has detected the presence of carbon dioxide and methane in the planet's atmosphere, along with a lack of carbon monoxide and ammonia — exactly as predicted by the hycean planet hypothesis. There's also tentative evidence that a compound called dimethyl sulfide, which on Earth is only produced by ocean plankton, also exists in K2-18b's atmosphere, but this evidence continues to prove contentious. Now a team of researchers at the University of California, Riverside and ETH Zurich in Switzerland have gone a step further. They propose that another family of compounds called methyl halides, generated by microbial ocean life on Earth, could produce a biosignature — that is, a chemical signature of biological life — in the atmosphere of a hycean world that's more easily detectable than the signature of oxygen is on an Earth-like planet. "Oxygen is currently difficult or impossible to detect on an Earth-like planet," said Michaela Leung of the University of California, Riverside, the first author of a new paper describing the research. "However, methyl halides on hycean worlds offer a unique opportunity for detection with existing technology." Methyl halides are molecules that incorporate carbon atoms and three hydrogen atoms attached to a halogen atom such as bromine, chlorine or fluorine. (Halogens are group of reactive, non-metallic elements.) On Earth, methyl halides are produced by life, but they are far from abundant in our planet's atmosphere. On hycean worlds, however, things could be different. Leung's team suspect that the conditions on such worlds, should they exist, would allow methyl halides to accumulate in large quantities in the atmosphere. Furthermore, methyl halides would have strong absorption features in infrared light, at the same wavelengths that the JWST is designed to observe. "One of the great benefits of looking for methyl halides is, you could potentially find them in as few as 13 hours with James Webb. That is similar or lower, by a lot, to how much telescope time you'd need to find gases like oxygen or methane," said Leung. "Less time with the telescope means it's less expensive." Related: The search for alien life RELATED STORIES —'Extremely Large Telescope' being built in Chile could detect signs of alien life in a single night —4 tiny, Earth-like planets found circling 2nd-closest star system to us — and could be visited by future human generations —James Webb telescope spots 'rogue' planet with a cake-like atmosphere barrelling through space without a star There are two caveats to what Leung's team propose. One is that we don't yet know whether hycean worlds actually exist. They were proposed as a possibility to explain certain properties of some warm sub-Neptune-type planets that have average densities that imply a thick hydrogen atmosphere and a deep ocean of liquid water. However, directly observing an ocean beneath such a world's hydrogen envelope is not currently feasible. The second issue is that we don't know if such oceans could be habitable. A hycean world would be hot, and although the extreme conditions beneath the hydrogen envelope would prevent the ocean from evaporating, it is uncertain whether it would be too hot for life as we know it. However, a positive detection of methyl halides in the atmosphere of a candidate hycean world would be a strong indication that life could exist there in a deep ocean. If life does exist on such a world, it would have to breathe hydrogen, not oxygen. "These microbes, if we found them, would be anaerobic," said Schwieterman. "They'd be adapted to a very different type of environment, and we can't really conceive of what that looks like, except to say that these gases are a plausible output from their metabolism." Anaerobic life — i.e., lifeforms making do without oxygen — exist on Earth, so it wouldn't be truly alien to life on our planet, even if the environment that it would live in is. Earth-like worlds orbiting red dwarfs could be in short supply, since red dwarfs are fierce little beasts, prone to unleashing bursts of harsh radiation that can strip away the atmosphere of an Earth-like planet. However, hycean worlds protected by their thick hydrogen atmospheres might be less vulnerable to attack from their star. It could therefore be that hycean worlds are where life resides in red dwarf systems, and since red dwarfs make up about three-quarters of all stars in our Milky Way galaxy, there could be many more habitable hycean worlds in the cosmos than Earth-like worlds. The research by Leung's team was published on March 11 in The Astrophysical Journal posted on
Yahoo
26-03-2025
- Science
- Yahoo
Scientists find unusual gas on exoplanets, could be the biggest clue in alien hunt
Could alien life exist on planets nothing like Earth? Scientists think a surprising new method could unravel this mystery. Researchers from the University of California, Riverside, suggest that certain gases detected in the atmospheres of exoplanets could be key indicators in the search for extraterrestrial life. These planets, which exist outside our solar system, can be observed using a James Webb Space Telescope (JWST), the largest telescope currently in halides are gases of a methyl group, which bears a carbon and three hydrogen atoms bonded to a halogen atom such as chlorine or bromine. On Earth, they are mainly produced by bacteria, marine algae, fungi, and certain plants. A key challenge in detecting these gases is that Earth-like exoplanets are too small and faint to be observed with the JWST. Instead, the most technically advanced telescope would have to focus on larger exoplanets orbiting small red stars. These exoplanets are called the Hycean planets, which are characterized by deep global oceans and thick hydrogen-rich atmospheres. While these worlds would be uninhabitable for humans, they could provide a suitable environment for certain microbes to thrive. 'Unlike an Earth-like planet, where atmospheric noise and telescope limitations make it difficult to detect biosignatures, Hycean planets offer a much clearer signal,' paper co-author Eddie Schwieterman said. The researchers believe that the search for methyl halides on Hycean planets could be an ideal strategy for looking for extraterrestrial life. 'Oxygen is currently difficult or impossible to detect on an Earth-like planet. However, methyl halides on Hycean worlds offer a unique opportunity for detection with existing technology,' Michaela Leung, the first author of the paper, said The researchers said that looking for such gases is easier than searching for other types of biosignature gas on other planets. 'One of the great benefits of looking for methyl halides is you could potentially find them in as few as 13 hours with James Webb,' Leung said. The researchers noted that the required telescope time to detect methyl halides is comparable or significantly lower than needed to identify gases like oxygen or methane. They added that requiring less telescope time makes the search more cost-effective. On the Earth, Methyl halides exist only in the trace. However, due to the unique atmospheric composition of Hycean planets and proximity to small red stars, these gases could build up to much higher concentrations—potentially making them detectable from light-years away. Researchers explained that any microbes in such environments would likely be anaerobic, but their metabolic processes would produce these gases. The study expands on previous research exploring biosignature gases, including dimethyl sulfide, another life indicator. However, methyl halides stand out due to their strong infrared absorption properties and the likelihood of their accumulation in hydrogen-rich atmospheres. The researchers noted that discovering methyl halides on multiple planets could suggest microbial life is widespread in the universe. Researchers plan to expand their work to other planetary environments and gases, using Earth's extreme locations, like the Salton Sea, as analogs. The researchers believe that while direct sampling of exoplanet atmospheres remains out of reach, advances in telescope technology could bring humanity closer to discovering alien life. 'Humans won't visit an exoplanet soon,' Schwieterman said, 'but knowing where to look is the first step in finding life beyond Earth.' The study is published in The Astrophysical Journal Letter.
Yahoo
23-03-2025
- Science
- Yahoo
James Webb Space Telescope could find signs of life on alien 'hycean' ocean worlds
When you buy through links on our articles, Future and its syndication partners may earn a commission. Hycean worlds, which are a possible kind of exoplanet with deep oceans surrounded by a thick envelope of hydrogen, could provide the best chance for the James Webb Space Telescope (JWST) to detect biosignatures, according to a new study. Those potential signs of life are a group of chemicals called methyl halides, which on Earth are produced by some bacteria and ocean algae. "Unlike an Earth-like planet, where atmospheric noise and telescope limitations make it difficult to detect biosignatures, hycean planets offer a much clearer signal," said Eddie Schwieterman, who is an astrobiologist at the University of California, Riverside, in a statement. For now, the existence of hycean planets remains hypothetical. Their name is a portmanteau of "hydrogen" and "ocean," first coined in 2021 by planetary scientist Nikku Madhusudhan of the University of Cambridge. Related: 'Hycean' exoplanets may not be able to support life after all Hycean planets are expected to orbit red dwarf stars, and the best candidate for a hycean world is the planet K2-18b. This exoplanet, which is categorized as a "sub-Neptune" world, orbits in the habitable zone of a red dwarf star 124 light-years from Earth in the constellation of Leo, the Lion. The Hubble Space Telescope discovered water vapor in K2-18b's atmosphere in 2019, and JWST has detected the presence of carbon dioxide and methane in the planet's atmosphere, along with a lack of carbon monoxide and ammonia — exactly as predicted by the hycean planet hypothesis. There's also tentative evidence that a compound called dimethyl sulfide, which on Earth is only produced by ocean plankton, also exists in K2-18b's atmosphere, but this evidence continues to prove contentious. Now a team of researchers at the University of California, Riverside and ETH Zurich in Switzerland have gone a step further. They propose that another family of compounds called methyl halides, generated by microbial ocean life on Earth, could produce a biosignature — that is, a chemical signature of biological life — in the atmosphere of a hycean world that's more easily detectable than the signature of oxygen is on an Earth-like planet. "Oxygen is currently difficult or impossible to detect on an Earth-like planet," said Michaela Leung of the University of California, Riverside, the first author of a new paper describing the research. "However, methyl halides on hycean worlds offer a unique opportunity for detection with existing technology." Methyl halides are molecules that incorporate carbon atoms and three hydrogen atoms attached to a halogen atom such as bromine, chlorine or fluorine. (Halogens are group of reactive, non-metallic elements.) On Earth, methyl halides are produced by life, but they are far from abundant in our planet's atmosphere. On hycean worlds, however, things could be different. Leung's team suspect that the conditions on such worlds, should they exist, would allow methyl halides to accumulate in large quantities in the atmosphere. Furthermore, methyl halides would have strong absorption features in infrared light, at the same wavelengths that the JWST is designed to observe. "One of the great benefits of looking for methyl halides is, you could potentially find them in as few as 13 hours with James Webb. That is similar or lower, by a lot, to how much telescope time you'd need to find gases like oxygen or methane," said Leung. "Less time with the telescope means it's less expensive." Related: The search for alien life Related stories: — Alien life could thrive on big 'hycean' exoplanets — What really makes a planet habitable? Our assumptions may be wrong — 10 exoplanets that could host alien life There are two caveats to what Leung's team propose. One is that we don't yet know whether hycean worlds actually exist. They were proposed as a possibility to explain certain properties of some warm sub-Neptune-type planets that have average densities that imply a thick hydrogen atmosphere and a deep ocean of liquid water. However, directly observing an ocean beneath such a world's hydrogen envelope is not currently feasible. The second issue is that we don't know if such oceans could be habitable. A hycean world would be hot, and although the extreme conditions beneath the hydrogen envelope would prevent the ocean from evaporating, it is uncertain whether it would be too hot for life as we know it. However, a positive detection of methyl halides in the atmosphere of a candidate hycean world would be a strong indication that life could exist there in a deep ocean. If life does exist on such a world, it would have to breathe hydrogen, not oxygen. "These microbes, if we found them, would be anaerobic," said Schwieterman. "They'd be adapted to a very different type of environment, and we can't really conceive of what that looks like, except to say that these gases are a plausible output from their metabolism." Anaerobic life — i.e., lifeforms making do without oxygen — exist on Earth, so it wouldn't be truly alien to life on our planet, even if the environment that it would live in is. Earth-like worlds orbiting red dwarfs could be in short supply, since red dwarfs are fierce little beasts, prone to unleashing bursts of harsh radiation that can strip away the atmosphere of an Earth-like planet. However, hycean worlds protected by their thick hydrogen atmospheres might be less vulnerable to attack from their star. It could therefore be that hycean worlds are where life resides in red dwarf systems, and since red dwarfs make up about three-quarters of all stars in our Milky Way galaxy, there could be many more habitable hycean worlds in the cosmos than Earth-like worlds. The research by Leung's team was published on March 11 in The Astrophysical Journal Letters.
The Independent
13-03-2025
- Science
- The Independent
Strange aliens could be hiding in gases, scientists say
Alien life could be hiding in gases, researchers have said. We could find extraterrestrial beings in gas on faraway planets that are very unlike our own, according to their new study. The gases themselves have been relatively neglected as a possible place to search for alien life. But it could actually be relatively easy and quick to examine, the scientists say. We could even do so by looking at exoplanets using Nasa's James Webb Space Telescope, they said. The gases themselves are called methyl halides. On Earth, they are usually made by bacteria, fungi, or similar – and they are made up of carbon and hydrogen atoms attached to a halogen atom. It would not be possible to see them on Earth-like planets, which are too small and dim to see with the Webb telescope. But other worlds, known as Hycean planets, could be possible places to search. 'Unlike an Earth-like planet, where atmospheric noise and telescope limitations make it difficult to detect biosignatures, Hycean planets offer a much clearer signal,' said Eddie Schwieterman, University of California Riverside astrobiologist and paper co-author. We don't know what the life forms that would produce such gases would look like – but they might look totally different from anything we've seen before 'These microbes, if we found them, would be anaerobic. They'd be adapted to a very different type of environment, and we can't really conceive of what that looks like, except to say that these gases are a plausible output from their metabolism,' Schwieterman said in a statement. The work is described in a new article, 'Examining the Potential for Methyl Halide Accumulation and Detectability in Possible Hycean-type Atmospheres', published in The Astrophysical Journal Letters.
