An Early, Muddy Mars Just Right for Life

摘要

When the Opportunity rover found the salty sedimentary remains of standing water on Mars, the prospects for early life on another planet brightened considerably. Although acid-laden, those early waters were nothing that martian life couldn't have adapted to. It's harder to imagine life originating under such conditions, however. Now, by analyzing the infrared "colors" of the martian surface, planetary scientists have identified clayey rocks that mark an even earlier warm and wet era, one more persistently wet and blessedly less acidic. The origin of martian life now looks brighter too.