In the mid-1970s, NASA sent two Viking landers to the surface of Mars equipped with instruments that conducted the only life detection experiments ever conducted on another planet. The results of those tests were very confusing at the time and remain so today. While some of them — particularly the labelled release experiment (which tested for microbial metabolism) and the pyrolytic release experiments (which tested for organic synthesis) — were initially positive for life, the gas exchange experiment was not.
At the time of those landings, scientists had very little understanding of the Martian environment. Since Earth is a water planet, it seemed reasonable that adding water might coax life to show itself in the extremely dry Martian environment.
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Now let’s ask what would happen if you poured water over these dry-adapted microbes. Might that overwhelm them? In technical terms, we would say that we were hyperhydrating them, but in simple terms, it would be more like drowning them. It would be as if an alien spaceship were to find you wandering half-dead in the desert, and your would-be saviors decide, “Humans need water. Let’s put the human in the middle of the ocean to save it!” That wouldn’t work either.
