In a potential landmark discovery, scientists using the James Webb Space Telescope have obtained what they call the strongest signs yet of possible life beyond our solar system, detecting in an alien planet’s atmosphere the chemical fingerprints of gases that on Earth are produced only by biological processes.

Further studies are needed to determine whether K2-18b, which orbits a star 120 light-years away, is inhabited, or even habitable.

Using the James Webb Space Telescope, a British-US team of researchers detected signs of two chemicals in the planet’s atmosphere long considered to be “biosignatures” indicating extraterrestrial life.