NASA's Perseverance rover just found something wild: signs that Mars was once a rainy, tropical place.
In the Jezero crater, the rover discovered rocks with kaolinite clay—a mineral that most commonly forms after ages of heavy rainfall on Earth.
Mars had a long, wet past
Scientists compared these Martian samples to similar clays from South Africa and San Diego and confirmed they formed under conditions similar to those in tropical climates on Earth.
That means ancient Mars likely had a humid climate for millions of years.
Why does it matter?
Finding this clay suggests Mars was once much more Earth-like—possibly even able to support life.
It also helps scientists piece together how the Red Planet went from lush and wet to dry and dusty today.
Perseverance will keep digging for more clues about Mars's lost water world.