A 360˚ view of an area nicknamed Bright Angel, where an ancient river flowed billions of years ago. The Cheyava Falls rock was found in this part of Mars. — The New York Times
LIFE, especially the microbes too small to see, has left an indelible mark on rocks on Earth, creating minerals that would otherwise not be there.
If some of those minerals turn up in rocks on Mars, is that not good evidence that life once existed there, too?
