Did NASA's Curiosity Rover Just Find Ancient Life On Mars?

 While analyzing Martian rock samples, the Curiosity rover found an unusual type of carbon. More specifically, a type often associated with life.

NASA scientists recently confirmed an 'intriguing' discovery of carbon on Mars — and one possibility of that carbon are remnants of ancient Martian life. Ever since humans started exploring the universe, Mars has been a constant point of fascination. The dusty, red planet has a solid surface, large deposits of frozen water, and is speculated to have once had ancient life billions of years ago.

While scientists and astronomers have learned a lot about Mars over the last few decades, confirming the presence of life isn't one of them. However, that's not to say the organization hasn't tried. The Curiosity rover landed on Mars in 2012 to see if the alien world was ever habitable for microbial life. Perseverance arrived in February 2021 with a similar mission, tasked with exploring Mars for signs of past and present life.

Per a new report published by NASA, it appears the team is one step closer to possibly detecting life on Mars. On January 17, the organization confirmed the Curiosity rover had found several carbon signatures after analyzing powdered rock samples. While this isn't the first time Curiosity's detected carbon on Mars, these specific samples "are rich in a type of carbon that on Earth is associated with biological processes." Assuming life on Mars happened the same way it does on Earth, the explanation of the unusual carbon is fairly simple. Assuming Mars did have ancient life, bacteria in the planet's surface would create carbon while releasing methane into Mars' atmosphere. UV light would then convert that gas into larger molecules, with those molecules coming back to the surface and hiding in rocks on the planet — hence the discovery of ancient Martian life.

This Carbon Doesn't Fully Confirm Ancient Life

But that hypothesis isn't confirmed. In fact, NASA believes there are two other explanations for the newly-found carbon. Another possibility is that the carbon originated from UV light interacting with carbon dioxide in Mars' atmosphere, eventually producing the carbon molecules Curiosity detected. Another explanation is that a 'rare event' created the carbon molecules hundreds of millions of years ago when "the solar system passed through a giant molecular cloud rich in the type of carbon detected."

So, which one is it? While it's ultimately too early to say for certain, NASA isn't eliminating the possibility that this carbon came from ancient life. Around half of the rock samples collected by Curiosity contained large amounts of carbon 12 — much more than what's previously been found in Mars's atmosphere and meteorites. Carbon 12 atoms are readily found on Earth when living things metabolize food or go through photosynthesis. For so much carbon 12 to be found in Martian rocks, it's an encouraging sign that some kind of life was once present on the planet.

For now, though, NASA isn't committing to one hypothesis over another. Now that the carbon's detected, scientists on the Curiosity team will measure it and compare it against carbon samples from other areas the rover visits. There's a lot more that needs to happen before this turns into a confirmation of life on Mars, but it's a small step in potentially getting there.