Researchers from the University of Cambridge have found the strongest signs yet of life outside our solar system.

They peered through the James Webb Space Telescope at a faraway world called K2-18b. It’s over twice the size of Earth, and it exists 700 trillion miles away, orbiting a different star to our sun.

The telescope detected chemicals on K2-18b that are only made by living things here on Earth. It’s either the case that life made them on K2-18b too, or that they were made in another way that we don’t know about.

Research leader Professor Nikku Madhusudhan thinks we’ll know the answer in the next year or two. He’s keen to be calm and careful, but said: “These are the first hints we’re seeing of an alien world that is possibly inhabited [lived on].”

To claim a true scientific discovery, researchers need to be 99.99999% sure that something exists – but the team aren’t that sure yet, and Ryan MacDonald, from the University of Michigan, is doubtful.

He said: “Any claim of life beyond Earth needs to be rigorously checked by other scientists and, unfortunately, many previous exciting claims for K2-18b haven’t withstood these independent checks.”