NASA’s Perseverance rover made a thrilling discovery on Mars: a rock sample containing minerals that on Earth are tied to microbial life. While not proof, it is one of the strongest clues yet that Mars may have once hosted organisms.

Nasa ’s Perseverance Rover has found some unusual rocks on the planet’s surface, hinting at potential past life there.

Sean Duffy, acting NASA Administrator, calling this “the closest we have ever come to discovering life on Mars” in an agency news release.