"The concept of a shadow biosphere is still just a theory. If someone discovers shadow life or weird life it will be the biggest sensation in biology since Darwin. We are simply saying, 'Why not let's take a look for it?' It doesn't cost much (compared to looking for weird life on Mars, say), and, it might be right under our noses."
Paul Davies, director -Arizona State University -BEYOND Center for Fundamental Concepts in Science
A famous theoretical physicist says we should search for "Shadow Life," unknown or undetected lifeforms that may have been hidden on Earth all along. We expect his team to consist of one military expert (male, stubbled), one technical expert (female, Asian), and three non-determinate other characters (at least one "funny") and a season cliffhanger after twelve episodes. Except it's real, and it's not unreasonable.
Whenever we talk about the origins of life we assume that there was only one - the one which led to us. This isn't pure egocentricity, though, as there is a complete lack of evidence of any other kind of life. Paul Davies says that may be because we don't recognize what we're seeing.
"Life as we know it appears to have had a single common ancestor, yet, could life on Earth have started many times? Might it exist on Earth today in extreme environments and remain undetected because our techniques are customized to the biochemistry of known life?" asks Davies, who also is the director of the BEYOND Center for Fundamental Concepts in Science at Arizona State University.
An "alien" biochemistry could have completely different effects from our own. They won't suddenly turn out to have been stalking us for years, horror-movie style - it doesn't matter if you're based on silicon or soap suds, enough life will leave some kind of visible mark. But they may exist in extreme environments where anything carbon based would choke or catch fire, and so be squirreled away in the remoter parts of the planet we haven't examined in any detail.
The idea of unconventional life isn't new - Stephen Baxter has made great use of alternatives to organics in his works - but serious rational discussion of "We might be wrong about everything, and what can we do if we are?" is why we've come so far as a species.
Posted by Luke McKinney.
Source: Arizona State University (2009, February 26). Cosmologist Explores Notion Of 'Alien' Life On Earth. ScienceDaily. Retrieved July 19, 2009, from http://www.sciencedaily.com /releases/2009/02/090214162626.htm