Earth and planetary scientists continue to explore a basic question. Has there ever been—and is there still— life on a now very arid Mars? Evidence seems clear that four billion years ago, Mars was a very different, waterrich planet with conditions not so unlike those here on Earth, where life bloomed and blossomed. On Mars, too, such conditions could well have triggered the emergence of microbial life wafting in ancient oceans. But now some scientists suggest that such life—if it existed—could have done itself in. How so?
According to a team led by Boris Sauterey (a post-doctoral researcher at Sorbonne University in France), hydrogen-eating, methane-producing microbes could have produced so much methane that they cooled the planet until it entered a virtually uninhabitable Ice Age. Temperatures may have dipped to minus 400°F.