Arsenic and "Life As We Know It"

A NASA press conference today featured several scientists describing a newly discovered life-form that defies previous assumptions about what is required for life to thrive.

Describing her research, Wolfe-Simon said "what I've presented to you today is a microbe doing something different than life as we knew it."

"I was taught as a biochemist that all life on Earth, all life we know of, to harken back to the 'pale blue dot' ideas of Carl Sagan, all life we know of is here so far," she said. "And if there's an organism on Earth that's doing something different, we've cracked open the door to what's possible for life elsewhere in the universe. And that's profound. ... This microbe substitutes arsenic for phosphorous in its basic biomolecules. What else might we find? What else might we want to look for?"