Rocks from the early history of Mars – almost four billion years
ago – suggest there might have been a habitable environment
underneath the surface of the planet, according to an October
2010 report by NASA and the Planetary Science Institute. NASA
planetary scientist Paul Niles is co-author of the report. He
told EarthSky: These rocks are evidence that there has been a
sub-surface hydrothermal system on Mars that could provide a
strongly habitable environment on Mars. In other words, these
rocks – exposed by an ancient meteor impact – show evidence of
heat and water beneath the planet’s surface. Heat and water,
says Niles, are necessary for an environment to be considered
habitable. You need to have liquid water, you need to have
organic material, and you need to have heat. We don’t have
evidence for organic material in these rocks directly, but we
have two out of three. Finding evidence for organic material
requires visiting that place with a surface mission. According
to Niles the rocks discovered in this