{"id":14174,"date":"2025-05-01T22:00:00","date_gmt":"2025-05-01T22:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=14174"},"modified":"2025-04-23T06:20:34","modified_gmt":"2025-04-23T06:20:34","slug":"alien-life-biosignatures-k2-18b-nasa-james-webb-may-2025","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/alien-life-biosignatures-k2-18b-nasa-james-webb-may-2025\/","title":{"rendered":"Scientists claim to have found evidence of alien life. But \u2018biosignatures\u2019 might hide more than they reveal"},"content":{"rendered":"\n\n\n
\n
\n \n
\n Artist\u2019s impression of the exoplanet K2-18b.\n A. Smith\/N. Madhusudhan (University of Cambridge)<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n Campbell Rider<\/a>, University of Sydney<\/a><\/em><\/span>\n\n

Whether or not we\u2019re alone in the universe is one of the biggest questions<\/a> in science. <\/p>\n\n

A recent study<\/a>, led by astrophysicist Nikku Madhusudhan at the University of Cambridge, suggests the answer might be no. Based on observations from NASA\u2019s James Webb Space Telescope, the study points to alien life on K2-18b, a distant exoplanet 124 light years from Earth.<\/p>\n\n

The researchers found strong evidence of a chemical called dimethyl sulfide (DMS) in the planet\u2019s atmosphere. On Earth, DMS is produced only by living organisms, so it appears to be a compelling sign of life, or \u201cbiosignature\u201d.<\/p>\n\n

While the new findings have made headlines<\/a>, a look at the history of astrobiology shows similar discoveries have been inconclusive in the past. The issue is partly theoretical: scientists and philosophers still have no agreed-upon definition of exactly what life is. <\/p>\n\n

A closer look<\/h2>\n\n

Unlike the older Hubble telescope, which orbited Earth, NASA\u2019s James Webb Space Telescope<\/a> is placed in orbit around the Sun. This gives it a better view<\/a> of objects in deep space. <\/p>\n\n

When distant exoplanets pass in front of their host star, astronomers can deduce what chemicals are in their atmospheres from the tell-tale wavelengths they leave in the detected light. Since the precision of these readings can vary, scientists estimate a margin of error for their results, to rule out random chance. The recent study<\/a> of K2-18b found only a 0.3% probability that the readings were a fluke, leaving researchers confident in their detection of DMS. <\/p>\n\n

\n