As the rover ascends, it moves along the Martian timeline, allowing scientists to study how Mars evolved from a planet that was more like Earth in the distant past, with a warmer climate and abundant water, to the icy desert it is today. The amount of frost on Mars’ equatorial volcanoes represents about 150,000 tons of water exchanged between the surface and the atmosphere every day during the cold season, equivalent to about 60 Olympic swimming pools. NASA’s Curiosity rover has discovered crystals of pure sulfur on Mars.