James Webb telescope may have discovered a mysterious, never-before-seen substance on Pluto and Titan

James Webb telescope may have discovered a mysterious, never-before-seen substance on Pluto and Titan A new study has identified a very specific wavelength of light missing from both Pluto and Saturn's largest moon, Titan. The surprising signal suggests that these worlds harbor an unknown molecule that has not yet been seen anywhere in the solar system or beyond. A mysterious wavelength of light is missing from the dwarf planet Pluto and Saturn's supersized moon Titan, new James Webb Space Telescope (JWST) observations show. The surprising discovery hints that these worlds harbor an unknown molecule that has not been seen in any other solar system world or exoplanet so far. Every element or molecule in the universe absorbs unique wavelengths of electromagnetic radiation. Therefore, one of the main ways astronomers study distant worlds — both inside and outside the solar system — is by closely examining the light that reflects off them and searching for dark "absorption lines" that correspond to the wavelengths of known chemical compounds. For example, molecular oxygen absorbs light at 230 nanometers, so if the electromagnetic spectrum of a faraway exoplanet has an absorption line at this frequency, researchers can be confident that its atmosphere contains oxygen, according to a 2021 study. JWST has proved to be exceptionally good at capturing electromagnetic spectra and identifying specific chemicals in exoplanet atmospheres, around distant stars and within primitive galaxies. It has even identified a molecule on one alien world that could point to extraterrestrial life. In a new study, uploaded June 11 to the preprint server arXiv, researchers analyzed JWST data from Pluto and Titan, focusing on very small wavelengths that have been relatively unexplored until now. This revealed a specific absorption line at around 5.11 micrometers in both worlds' spectra. (These findings have not been published in a peer-reviewed journal yet.) The team pored through similar studies on other planetary spectra but "did not find any band referenced in these publications that corresponds to the location of the observed absorption in Titan and Pluto," the researchers wrote in the paper. A molecular mystery The discovery is even stranger because there are very few similarities between Pluto and Titan that could explain why they share a molecule not found anywhere else. Get the world’s most fascinating discoveries delivered straight to your inbox. Titan is the largest of Saturn's many moons and is even larger than Mercury. It is also the only solar system world, other than Earth, that is known to have liquid rivers and oceans on its surface. Pluto, on the other hand, is a completely frozen world that's around half the size of Titan and roughly four times farther from the sun than Saturn's satellite is. Both worlds do have similar atmospheres that are rich in methane and nitrogen. However, the researchers are confident that the molecule responsible for the 5.11-micrometer absorption line is located on both worlds' surfaces, not in their atmospheres. Pluto's absorption line is around three times thicker than Titan's, meaning the mystery molecule is likely much more abundant on the dwarf planet. But on Titan, the molecule seems to be unevenly distributed, with a stronger absorption line on its trailing side — the hemisphere opposite to its forward momentum around Saturn — than on its leading side. RELATED STORIES - 'Utterly cataclysmic': James Webb telescope spots 2 alien planets disintegrating before our eyes - James Webb Space Telescope discovers oldest organic molecules in the known universe, 12 billion light-years from Earth - 'What the heck is this?' James Webb telescope spots inexplicable planet with diamonds and soot in its atmosphere The researchers proposed that it could be benzene — a ring-shaped hydrocarbon — mixed with an unknown molecule, or some form of acetylene or ketene ice. However, much more work is needed to prove that any of these potential candidates are responsible for absorbing this specific wavelength, they wrote. NASA's Dragonfly spacecraft, which is set to launch no earlier than 2028 and fly through Titan's atmosphere in 2034, could eventually shed more light on the situation. The helicopter-like craft's onboard spectrograph could identify the mystery molecule on Saturn's moon, which would also help reveal if it is viable on Pluto, the researchers suggested. But in the meantime, we'll have to wait to unravel this curious cosmic conundrum. See how well you know our planetary neighborhood with our solar system quiz! Harry is a U.K.-based senior staff writer at Live Science. He studied marine biology at the University of Exeter before training to become a journalist. He covers a wide range of topics including space exploration, planetary science, space weather, climate change, animal behavior and paleontology. His recent work on the solar maximum won "best space submission" at the 2024 Aerospace Media Awards and was shortlisted in the "top scoop" category at the NCTJ Awards for Excellence in 2023. He also writes Live Science's weekly Earth from space series. 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