NASA's Curiosity rover has provided crucial evidence supporting theories about Mars' environmental past. Planetary scientists believe Mars once had a carbon dioxide atmosphere and liquid water on its surface. A significant challenge to this theory was the lack of identified carbonate rocks, which should have formed from the interaction of carbon dioxide and water.
Carbonates, minerals containing carbon and oxygen ions, are common on Earth. Despite extensive searches by rovers and satellites, significant quantities of carbonates had not been found on Mars. This raised doubts about the theory of a past Martian atmosphere rich in carbon dioxide and the presence of liquid water.
However, recent data from the Curiosity rover has revealed the presence of carbonates right beneath the rover. This discovery supports the theory that Mars once had a carbon dioxide atmosphere and liquid water. The findings mark a significant milestone in understanding Mars' environmental history and potential for past habitability.