Astronomers searching for alien life aimed the James Webb Space Telescope at K2-18 b, a potentially ocean-bearing world 124 light-years away, and found tentative signs of gases associated on Earth with marine microbes — triggering months of debate over whether the molecules were really there and whether they would indicate life.

A faint spectral signature hinting at gases tied to Earth's ocean life has scientists arguing whether we're seeing biosignatures or just chemistry. The post Astronomers searching for alien life aimed the James Webb Space Telescope at K2-18 b, a potentially oc…