If life exists on Mars, it still hasn’t showed itself—but recent evidence from the Red Planet increasingly supports the possibility. Life could have developed there. Most of the conditions are right, and nothing found so far rules out the possibility, either in the distant past or today.
If something is or was alive on the Red Planet, it’s probably tiny. Because microbes make up the vast majority of life on Earth and live in its most inhospitable environments, they are the most likely thing to find somewhere else. It’s not so easy figuring out what “alive” means on another planet—let alone discovering a living microbe. Scientists are still puzzled by life on Earth— struggling to understand how life started, what it requires to survive, what it looked like 4 four billion years ago, and how to recognize traces of ancient life today.