Scientist Becoming More Convinced Life Started On Mars - Follow The Water

Monday, May 4, 2015

Scientist Becoming More Convinced Life Started On Mars - Follow The Water

NEW YORK - The search for life beyond Earth homes in on water, whose abundance throughout the solar system is becoming increasingly clear to scientists.

Scientists think Mars once had an ocean that covered 20 percent of its surface. Most of that water was subsequently lost to space.

Water is a polar molecule and a solvent, two properties that are important for certain chemical reactions critical to life, said NASA chief scientist Ellen Stofan.

"We think water is key to life as we know it," Stofan said Tuesday (April 28) during the Asimov Memorial Debate, an annual event at New York's American Museum of Natural History that was moderated by Neil deGrasse Tyson, director of the museum's Hayden Planetarium. [5 Bold Claims of Alien Life]

And Earth is certainly not the only world with ample stores of the stuff.Jupiter's moon Europa is covered with a sheet of ice that very likely sits on top of a global ocean, and Saturn's moon Enceladus shows evidence of subsurface water as well. Mars, meanwhile, was once a relatively warm and wet world that apparently harbored large amounts of liquid water in the ancient past for a long period of time — perhaps up to a billion years, Stofan said.

Astrobiologists regard Europa and Enceladus as viable candidates to host alien life today. While researchers might not find life on Mars now, it might have existed there once, Stofan said.

"Many of us in the scientific community have a pretty strong belief, based on science, that at some point life was likely to have evolved on the surface of Mars," Stofan said. "The hard part is going to be finding it."

Any Martian life that is found is likely to be microbes, not "little green men," she added.

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