Perseverance Pays Off

Humans have always wondered whether they are alone in the universe.

Now, scientists have examined a sample that NASA’s Perseverance Mars rover collected last year from an ancient dry riverbed in Jezero Crater and found that the sample could preserve evidence of ancient microbial life.

The sample, known as Sapphire Canyon, was collected from a rock known as Cheyava Falls: A new study has found that it contains potential biosignatures.

“This finding (…) is the closest we have ever come to discovering life on Mars,” acting NASA administrator Sean Duffy said in a statement. “The identification of a potential biosignature on the Red Planet is a groundbreaking discovery.”

A potential biosignature is a substance or structure that might have a biological origin and could confirm the presence of life, with more analysis.

The rover reached Cheyava Falls in July 2024 while exploring the Bright Angel formation, a series of rocky outcrops along the northern and southern edges of Neretva Vallis – an ancient river valley carved by water that flowed into Jezero Crater long ago.

Perseverance found that the formation’s sedimentary rocks are made of clay and silt, which on Earth are known as great preservers of past microbial life. They are also rich in organic carbon, sulfur, oxidized iron (rust), and phosphorus.

“The combination of chemical compounds we found in the Bright Angel formation could have been a rich source of energy for microbial metabolisms,” study author Joel Hurowitz said in the statement. “But just because we saw all these compelling chemical signatures in the data didn’t mean we had a potential biosignature. We needed to analyze what that data could mean.”

Similarly, the rover’s instruments found what looked like colorful spots while examining Cheyava Falls, which may have resulted from microbial life if it had used the rock’s materials – vivianite and greigite – as an energy source, Hurowitz explained.

Vivianite is often found on Earth in sediments, peat bogs, and around decaying organic matter. Similarly, some forms of microbial life on Earth can produce greigite.

Still, the minerals can also be the product of high temperatures and other causes not related to biological life.

Even so, the rocks at Bright Angel didn’t display evidence that they underwent high temperatures or other conditions that produce those chemicals, researchers said.

The discovery is all the more surprising because it comes from some of the youngest sedimentary rocks the mission has investigated. Researchers had believed that signs of ancient life would come from older rock formations. This indicates that Mars could have been habitable for a longer or later period in its history than once believed, and that older rocks might contain signs of life that are more difficult to detect.