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Will we know extraterrestrial life when we see it?
Recognizing life on other worlds requires wiggle room in the definition of what it means to be alive By Tina Hesman Saey 12:00pm, April 18, 2016 LIFE ON MARS A Martian microbe, envisioned by planetary geologist Kathie Thomas-Keprta, would need a tough outer wall to withstand the elements and…