Astronomers Say They’ve Recorded the Strongest Sign Yet of Life Beyond Earth

Look alive: 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 dime ... Read full article.