Astronomers Say They’ve Recorded the Strongest Sign Yet of Life Beyond Earth
AnonTechie writes:
New JWST data strengthens earlier hints that K2-18b, a possible water world 120 light-years away, could host the chemical byproducts of life.
The James Webb Space Telescope (JWST) may have picked up signs of a potential biosignature on a steamy, ocean-covered exoplanet called K2-18b-a biosignature that, on Earth, is produced by marine life.
The main character here is dimethyl sulfide, a molecule produced by many ocean denizens, but especially plankton. If the molecule is really floating around in the atmosphere of K2-18b, it raises the tantalizing possibility that something on the world might be alive. Or at least emitting suspiciously life-like chemical signals.
K2-18b, located 120 light-years away, has been on scientists' radar since NASA's Kepler space telescope spotted it in 2015. It's about 8.6 times the mass of Earth and orbits within the habitable (or "Goldilocks") zone of a red dwarf star.
Earlier observations from Hubble hinted that K2-18b had water vapor in its atmosphere, a claim later shown to be in error. But JWST has taken matters several steps further, doubling down on an earlier finding of dimethyl sulfide in the planet's atmosphere. The team behind the discovery, led by Nikku Madhusudhan from the University of Cambridge, includes researchers from five institutions.
The finding suggests that K2-18b may indeed be a Hycean world, or a water-covered planet with a hydrogen-rich atmosphere. But the team's observations-made using JWST's Mid-Infrared Instrument (MIRI) and earlier data from NIRISS and NIRSpec-revealed methane and carbon dioxide, but very little ammonia, on the planet.
[...] Further observations will help to validate the team's findings. But to be clear, if life does exist on K2-18b, it's likely microbial given the apparent evidence, and not a sign of alien intelligence. As an important aside, microbial life-like plankton-existed on Earth for a billion years, a long but crucial chapter that paved the way for more complex organisms to emerge. Regardless, life has never been found beyond Earth, so confirming even a single amoeba on a distant world would be nothing short of revelatory.
At minimum, K2-18b is shaping up to be one of the most promising places to search for life beyond Earth. And at maximum-if further studies validate the recent findings-we may be getting our first chemical whiffs of a living ocean on another world.
[Source]: Gizmodo
[Journal Ref]: The Astrophysical Journal Letters
[Also Covered By] BBC
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