Scientists have found the first fossil evidence of an environment that could have supported life on Mars billions of years ago. The evidence consists of hexagonal patterns in ancient Martian mud that indicate a cyclical climate with wet and dry seasons, reports thedebrief.org.
The discovery was made by a team of researchers from France, the US and Canada, using data from NASA’s Curiosity rover. The rover has been exploring a region of Mars called Gale Crater since 2012, where it has detected simple organic molecules that could be building blocks of life.
However, to confirm the possibility of life on Mars, the scientists also needed to find evidence of a suitable environment for these molecules to form and persist. That’s where the hexagonal patterns come in.
The patterns are formed by salt deposits in layers of sediment that date back to between 3.6 and 3.8 billion years ago. They resemble mud cracks that form on Earth when wet soil dries and contracts, creating polygonal shapes.
The researchers say that the presence of these cracks on Mars suggests that the planet once had a climate with seasonal changes, similar to Earth.
“This is a major discovery, because it shows that Mars was not always a cold and dry desert, but had periods of wetness and warmth that could have favored the emergence of life,” said William Rapin, the lead author of the study and a researcher at France’s Institut de Recherche en Astrophysique et Planétologie.
The study, published in the journal Nature, also suggests that Mars had a thicker atmosphere in the past, which could have protected it from harmful radiation and allowed liquid water to exist on its surface.
The researchers hope that their findings will help shed light on the origin and evolution of life on Mars, as well as on Earth and other planets.
“This is a unique opportunity to study the history of an ancient world that may have been habitable at some point, and to compare it with our own,” said Rapin.
The study is based on data from Curiosity’s Mastcam and ChemCam instruments, which can capture images and analyze the chemical composition of rocks and soils on Mars.