NASA Did Not Say It Found Life on Mars. But It’s Very Excited About This Rock.

The rock, studied by NASA’s Perseverance rover, has been closely analyzed by scientists on Earth who say that nonmicrobial processes could also explain its features.

Scientists working with NASA’s Perseverance rover state emphatically that they are not claiming to have discovered life on Mars.

But many would regard a rock that the rover just finished studying as “Most Likely to Contain Fossilized Microbial Martians.” The rover has drilled and stashed a piece of the rock, which scientists hope can be brought back to Earth in the coming years for closer analysis and more definitive answers.

“What we are saying is that we have a potential biosignature on Mars,” said Kathryn Stack Morgan, the mission’s deputy project scientist. She describes a biosignature as a structure, composition or texture in a rock that could have a biological origin.

The rock, which scientists named Cheyava Falls, possesses features that are reminiscent of what microbes might have left behind when this area was warm and wet several billion years ago, part of an ancient river delta. The scientists clarified that they did not spot anything that they thought might be actual fossilized organisms.

Scientists have wondered if life could have arisen on early Mars when it possessed an atmosphere, climate and flowing water. Martian rocks could hold important clues.

The Cheyava Falls find “is, for me at least, the most compelling rock that we have collected so far,” said Kenneth Farley, the mission’s project scientist and a professor of geochemistry at the California Institute of Technology. If the rock could be brought to Earth for study, he added, “it has the potential to really get at the question” of whether life ever existed on Mars.