But that's a big deal because microbes evolve. For 90 percent of the time that life existed on Earth, there were only microbes, said Bruce Jakosky, a professor of geological sciences at the University of Colorado. Microbes are "where we come from," he said.
Jakosky and McKay said it also could eventually mean that life started in more than one place in the universe.
"If there's microbial life widespread throughout the galaxy, that increases the chances that there's intelligent life elsewhere," Jakosky said.
NASA's astrobiology institute: http://astrobiology.nasa.gov
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