Mashable carries news from NASA’s Curiosity rover, which has found traces that ancient ripples left on primordial lake beds, which prove that far from being an ice-covered badland, Mars was once warm, wet, and hospitable to life:
These ripples formed some 3.7 billion years ago. (For reference, the earliest known fossils on Earth formed some 3.5 billion years ago.)
“Extending the length of time that liquid water was present extends the possibilities for microbial habitability later into Mars’s history,” Claire Mondro, a Caltech postdoc who researches the planet’s past and led the new study, said in a statement.
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Yet for millions of years, Mars at least had the opportunity for life to flourish in lakes, or the moist clays of river deltas. NASA hopes to robotically return pristine Mars rock samples home in the 2030s; the space agency thinks they could potentially show evidence of past surface life.
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Photos at the link. You can read more of the Curiosity findings here, in Science Advances.