"A truly fantastic result": what is this life form discovered on Mars and announced by NASA?

With some excitement, NASA announced at a press conference on Wednesday, September 10, that rocks collected by the Perseverance rover in July 2024 could be " the clearest sign ever found" of life on Mars .

Yet the suspense remains. In the article published by the team of scientists overseen by the American Agency in the leading journal Nature , the experts are cautious.

However, they recognize the obvious interest of these three-billion-year-old samples collected in the ancient delta of a lake on the Red Planet. Perseverance's instruments have notably identified two minerals, vivianite and greigite, which give the sample its very distinctive speckled shape.

"This rock formed in an environment rich in liquid water. We discovered spots and nodules of the order of a millimeter, a little more blue and green than the usual red environment," Caroline Freissinet, CNRS researcher in planetary sciences at Latmos , a laboratory in Guyancourt (Yvelines), told BFMTV. She did not work on this study but has already collaborated on work concerning Curiosity , the other Martian exploration vehicle.

"Analysis using instruments on board the Perseverance rover shows that these spots are less oxidized than the rest of the rock," the researcher continues.

Two hypotheses are being considered to explain this reaction. The first, and less exciting, is that it is a purely geological phenomenon. "A rock can reduce minerals and create this type of structure when it comes into contact with a heat source or organic matter," she explains.

The possibility that encourages scientists to see this as an ancient form of life is that of a biological phenomenon. "Similar structures have been found with these minerals on Earth. We know that these spots were formed by chemical reactions that support life in environments where there is water and iron."

By analogy, researchers believe that these minerals may have formed on Mars just as they did on Earth.

Since their collection, these rock samples have been inside Perseverance where they have undergone a battery of tests and analyses using the various tools on board the rover, which made a spectacular landing on Mars in February 2021. The publication of these results today demonstrates the limits reached by the analysis of rocks on Mars. The scientific community now hopes for further studies on Earth.

"It's truly a fantastic result from the point of view of understanding the Martian past. However, on board Perseverance, we have limited instruments, there is an instrumental payload which is what it is, we cannot carry out all the analyses that we could do in the laboratory," explains Caroline Freissinet.

It is therefore impossible to decide between the two hypotheses without the return of Martian samples to Earth. However, Donald Trump has adopted budget cuts that have melted NASA's resources to finance this program in particular.

"If the Martian sample return program is not maintained, this sample will remain on board Perseverance with its mysteries. Without very strong political support, we will remain in the dark. We will know that we have mysterious formations on the surface of Mars that resemble biological formations, like those found on Earth, but we will never be able to know and determine whether on Mars they are of geological or biological origin," she laments.