Friday, March 20, 2009

Origin of life: Researchers claim life could have existed 4.4 billion years ago, before Earth cooled.

Just when claims for Akilia, as evidence of life at 3.82 billion years ago have not held up, some researchers are even more ambitious.

As reported in New Scientist, Oleg Abramov and Steve Mojzsis of the University of Colorado in Boulder suggest that life could have existed on earth as early as 4.4 billion years ago:
... hardy life-forms could have survived if they were buried underground.
They were using a computer model and they assumed that these primeval life forms were extremophiles (simple, extremely hardy life forms).
... heat from the impacts would not have penetrated very deeply into the underlying solid crust. The layer heated to the sterilisation point, about 110 ̊C, would be only about 300 metres thick. High-temperature 'extremophile' microbes, like those in the hot springs of Yellowstone National Park, would have survived at greater depths, down to their limit of about 4 km.
Mojzsis argues that the Late Heavy Bombardment of Earth by asteroids "pruned, rather than frustrated, life."
That conclusion is reasonable, says Kevin Zahnle of NASA's Ames Research Center in California.
It certainly is, if you are looking for an argument that God created the first life on Earth. I wonder if either he or New Scientist have thought this one out ....

Abramov and Mojzsis will present their research to the Lunar and Planetary Science Conference in Texas on March 23. Here's the .pdf.

In fairness, I must warn you that I consider New Scientist the National Enquirer of popular science magazines, and I am also wary of computer models in these situations. So I would just wait and see.

See also: Podcast: Chemist Charles Garner on chemical evolution; Why the Huygens probe - sadly - probably won't tell us much; Mars red but not dead?; NASA says, could be life on Mars, could be rocks; Origin of life: What can the Saturnian moon Titan tell us?; Origin of life: Alien origin taken seriously? Ghost of Francis Crick smiles wanly; Origin of life: A meatier theory? Or just another theory?; Origin of life: There must be life out there vs. there can't be life out there; Origin of life: Oldest Earth rocks may show signs of life, in which case ... ; Origin of life: Positive evidence of intelligent design?; Origin of life: But is being greedy enough?; Origin of life: Ah, that "just so happens" intermediate series of chemical steps; Why should the search for Darwin's "warm little puddle" be publicly funded?

(Note: The photo shows an extremophile, a simple, heat-loving organism.)