Scientists find strongest evidence yet of life on another planet

A team of researchers using NASA’s James Webb Space Telescope have found what they say is the most compelling evidence to date of extraterrestrial life, located ~120 light-years from Earth on a planet called K2-18b, per a new study.

Let’s break it down

K2-18b has a radius ~2.5x larger than Earth and lies within its star's habitable range, meaning liquid water could exist on the planet’s surface if other conditions are right.

• After a repeated analysis of K2-18b using JWST data, scientists detected the presence of “biosignatures,” or chemicals present at a level that, on Earth, is only known to come from living organisms. It marks “the first time humanity has seen potential biosignatures on a habitable planet,” the study’s authors said.
• In particular, the identified biosignature is a byproduct of marine algae—leading researchers to conclude that the best explanation for their observations is that K2-18b contains a warm ocean brimming with life.

However…The new research carries a “but” large enough to please Sir Mix-a-Lot. Many experts note that scientists are still learning how to use the JWST to analyze the make-up of alien atmospheres. And even if the biosignature from K2-18b is confirmed, scientists still have to figure out whether that chemical could be produced by previously unknown processes that don't involve life—with several recent studies indicating the answer is “Yes.”

Looking ahead: Scientists plan to run further experiments to make sense of the new JWST study, including recreating the possible conditions on planet K2-18b.