Dimethyl sulfide is in the news after NASA's James Webb Space Telescope may have detected relatively high levels of it in the atmosphere of an exoplanet called K2-18 b
Scientists and extraterrestrial enthusiasts are abuzz after a team of researchers studying the atmosphere of an exoplanet called K2-18 b with NASA's James Webb Space Telescope (JWST) just announced that they detected high levels of either the chemical dimethyl sulfide or a very similar compound—billing it as a hint of alien life. Although most people have never heard of dimethyl sulfide, it's all around us here on Earth. But what is this compound, and is it really a sign of life beyond Earth? What Is Dimethyl Sulfide? In chemical terms, dimethyl sulfide comprises one atom of sulfur bonded to two methyl groups, each of which contains one carbon atom and three hydrogen atoms. The result is a small molecule with an outsize ability to offend the human nose. "Any of these sulfur things are going to be super stinky—that garlic, rotten egg smell," says Eleanor Browne, a chemist at the University of Colorado Boulder. On supporting science journalism If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today. Earth's dimethyl sulfide is constantly being produced by tiny plankton in the oceans. From there, it rises into the atmosphere, where it makes up about one out of every billion molecules. Once aloft, each individual molecule of dimethyl sulfide lasts only hours or, at most, about a day before it is destroyed in reactions that are triggered by exposure to sunlight and various atmospheric compounds. That process is scientifically important here on the surface, Browne says, because those reactions eventually create tiny particles called aerosols that seed clouds, making dimethyl sulfide an important compound to understand for climate models and other…