Alien life may be all around us (or even in us), says professorFebruary 15, 2009
Daily Mail, UK
Forget little green men on Mars - aliens could be right here on Earth, a leading scientist has claimed.
Cosmologist Paul Davies said it was 'entirely reasonable' to believe that we share the planet with a form of life different to anything we know of.
This 'life, but not as we know it' might be lurking in poisonous lakes or deep under the sea or could even be inside our bodies.
Professor Davies said: 'It could be right under our noses, or even in our noses. It could even be that "weird life" and real life are intermingled.'
Calling on scientists to launch a 'mission to Earth', he said it was possible that life had evolved more than once, meaning we are not alone on our planet.
He said: '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 today in extreme environments and remain undetected because our techniques are customised to the biochemistry of known life?
'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 just look for it?"
'It doesn't cost much compared with looking for weird life on Mars.'
Professor Davies, of Arizona State University, said any aliens that do exist on Earth will be too small for the naked eye to see.
Their unusual biochemistry could allow them to thrive in arsenic-rich lakes or in blistering hot vents underneath the ocean.
There is even a theory that alien particles, a tenth the size of bacteria, live inside our bodies and trigger the formation of kidney stones, the American Association for the Advancement of Science's annual conference in Chicago heard.
The British-born professor said: 'Although such claims remain controversial, it is conceivable that at least some of these Lilliputian forms are alien organisms employing a radically alternative biochemistry.
'Even if alternative life does not exist now, it might have flourished in the distant past before dying out for some reason.
'In that case, scientists might still be able to find markers of their distinct biology in the geological record.
'If alternative life had a distinctly different metabolism, say, it might have altered rocks or created mineral deposits in a way that cannot be explained by the activities of known organisms.'
Even some of the bacteria that scientists find difficult to grow and work with might be weird life with an alien biochemistry, the Chicago conference heard.
The professor said that if life is proved to have evolved more than once on Earth, it would vastly boost the case for there being life on other planets.
He said: 'As more terrestrial environments are explored, it seems very likely that new and ever more exotic forms of life will be discovered.
'If this search were to uncover evidence for a second genesis, it would strongly support the theory that life is a cosmic phenomenon and lend credence to the belief that we are not alone in the universe.'
Jill Tarter of the Search for Extra-Terrestrial Intelligence project, said: 'It is really important to engage people in thinking about astrobiology and life as we don't know it on Earth.
'As we do so, it expands our perspective, it changes our point of view and it trivialises the differences between humans.
'If we can get the world to think about life in a different way, all humans as being one species, I think we can do a lot to change the world.'