By Jeffrey Kluger, January 20, 2022 11:54 AM EST
Mars is both a wonderful and a terrible place to go looking for life. On the one hand, the planet is a wasteland, where wintertime temperatures plunge to -153º C (-225º F), and the atmosphere—such as it is—is just 1% the density of Earth’s and composed principally of carbon dioxide.
On the other hand, the Red Planet wasn’t always such a wreck. For the first billion or so years of its 4.5 billion year life span, it was awash in oceans and seas and protected by a thick blanket of air. Eventually, however, its magnetic field shut down, allowing the solar wind to claw away the atmosphere and the water to vanish into space.
But that first billion years offered Mars plenty of time to cook up at least microbial life, some of which may have died and left chemical traces on the surface—or even have retreated underground to continue thriving in deep, warm aquifers.
Now, a new study, announced by NASA and published on Jan. 18 in the Proceedings of the National Academy of Sciences, suggests that some of those lingering surface markers of ancient life may have been found—lying in plain sight, in fact.