The Search for Life

When we turned our telescopes to the heavens and looked for life, our first thoughts were to seek creatures like those we knew down here on Earth.

Percival Lowell looked at Mars... thought he saw canals, and inferred an alien civilization that built these channels to bring water across dry deserts to thirsty cities.

And in the 20th century, when the Viking spacecraft showed us landforms that looked a little like a human face, tabloid newspapers and others rushed to claim more proof of life on Mars.

In reality, Lowell's canals were the result of telescopic distortion...

And the face on mars, as more recent images from Global Surveyor show, is really wind-blown rock.

If we want to look for life, we have to be able to recognize it even when it doesn't look like life as we know it...


Ken Nealson
Director, Center for Life Detection
Jet Propulsion Laboratory, NASA/Caltech

Can we develop methods that would detect life, even if it wasn't made of the same stuff that it is on Earth and even if it were fundamentally different? Uh, by doing this we turn the search for life into a physics and chemistry and statistics problem, rather than just a biology problem.