If we found alien life, would we know it?

NASA has searched for extraterrestrial life in our solar system. Someday we might encounter life on distant worlds, perhaps one of the three earthlike planets in orbit around the nearby star Glise 581. But what if it’s so different from life on Earth that we can’t recognize it?

That’s the question scientists are asking at NASA as they prepare to launch missions in search of extraterrestrial life within our own solar system. A 2007 report from the National Research Council recommended widening this search to include what they called ‘weird life.’

Steven Benner is a scientist at the Foundation for Applied Molecular Evolution, and contributed to the report. He said the basic assumption about life is that it’s like us – it’s carbon-based and requires water to survive. But that might not be the case in the rest of the universe. Weird life is life that we’ve never seen and maybe never imagined.

But how do we search for life that we can’t imagine? Benner said there are two ways: We can start with our own genetic code in the lab, and play around with the structure. Or we could look at the environment we might be landing on and try to create a chemical structure that might exist there. The only rule is that weird life must be able to reproduce and evolve.

So the alien life that we find might not look anything like the aliens we see in the movies.

Our thanks to:
Steven Benner
Institute for Applied Molecular Evolution

November 7, 2007

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