Life on Mars: What If NASA Actually Finds It?

Today Mars is a wasteland. It is a dusty desert, harsh and cratered. There is no visible life on its surface. But in recent decades, scientists have found evidence of a lost Mars that looked a lot more like Earth than a hellhole.

“You can see evidence of what Mars looked like 4 billion years ago,” says NASA astrobiologist Lindsay Hays. Etched into its rocky surface, “you see things like what’s left of a huge river delta,” she says. You see references to past lakes. That stimulates the imagination. “There may have been clouds in the atmosphere,” says Hays. “The surface would have been absolutely beautiful.Previous missions to Mars — including with robotic rovers, landers, and orbiters — have added on-the-ground evidence that this watery past is highly probable.

And that’s the most exciting thing for an astrobiologist like Hays: where there was water, there could have been life. “One of the universal characteristics of life is that it needs water,” she says. There is life that survives without light, life that survives without oxygen. Nothing we know of life without water. If there was water on the surface of ancient Mars, “well, maybe life lived in that water,” she says.

A recent episode of Inexplicable – Vox’s podcast exploring big mysteries, unanswered questions and all that stuff we Learn by Diving into the Unknown – is about the search for key evidence that would confirm whether life existed on ancient Mars.

Perseverance, NASA’s newest rover to land on the red planet in 2021, is currently exploring an ancient dry river delta. The hope is that some form of microbial life that lived — and died — in its sediments billions of years ago is preserved. (It’s less likely that anything currently lives on Mars.) The rover is in search of rock samples that can eventually be returned to Earth for close examination; They would be the first Martian rocks brought back to Earth by a scientific mission (we have some samples of Martian rock that came to Earth via a meteorite).

But… what if we find it? What if evidence of past life on Mars is confirmed?

Finding life on Mars could help us understand how common life is in the universe

“The reason I’m interested in the search for life has to do with this concept of how life on Earth is connected,” explains Hays.

Any two people are related by a common ancestor if you look far enough back in their family trees. But the same is true of all life. There is a common evolutionary ancestor linking a human to a chimpanzee, a chimpanzee to a frog, a frog to an insect, an insect to a fungal spore. All life on Earth is related via the Last Universal Common Ancestor (or LUCA), a hypothetical microbe that lived billions of years ago.

For Hays, this relationship raises an epic question.

“So knowing that all life on this planet appears to be related, what would life be like on another planet?” she asks.

If Perseverance finds evidence of past life on Mars, it’s possible, but not guaranteed, that scientists could determine if it likely shared a common ancestor with life on Earth. (“All life on Earth has certain similarities,” she says, “using DNA/RNA for storing ‘information’ and most of the same amino acids in their proteins. If we’ve found life on Mars that shares those similarities ‘, then perhaps related to life on earth.

If life on Earth and Mars shared a common ancestor, that means life might have started on one of the planets and then somehow transported to the other (probably by a meteorite). It’s possible that life didn’t begin on Earth, but on Mars, or maybe even somewhere else in space.

But if life on Mars appears very different from life on Earth, it could mean that “life is such a fundamental process of the universe that there can be two different life-generating events in the same solar system,” says Hays . This means that life in the universe may be even more common than we currently suspect.

Hays warns that answers to these epic questions may still elude us, even with the best of rock samples. Scientific evidence is often ambiguous, and there is certainly debate about any sweeping conclusion.

But the fact remains: Mars is an enormously important place in our solar system to study these questions.

And right now there could be a simple rock on the surface of Mars with epic evidence inscribed on it. Maybe, just maybe, our robotic rover will find that rock, collect it, and show us how special life really is.

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