Astronomers have detected possible chemical signs of life on a faraway planet. But they caution much more work is needed to confirm their findings.

A chemical called dimethyl sulfide popped up in an analysis of exoplanet K2-18b’s atmosphere. On Earth, it’s only made by living organisms.

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 exoplanet’s atmosphere the chemical fingerprints of gases that on Earth are produced only by biological processes.