May 20, 2009

A Benevolent Sort of Asteroid Bombardment?

Written by Anne Minard

Celestial impacts can bring life as well as wipe it out, say the authors of a new study out of the University of Colorado at Boulder.

A case in point: the bombardment of Earth nearly 4 billion years ago by asteroids as large as Kansas would not have had the firepower to extinguish potential early life on the planet and may even have given it a boost.

In a new paper in the journal Nature, Oleg Abramov and Stephen Mojzsis report on their study of impact evidence from lunar samples, meteorites and the pockmarked surfaces of the inner planets. The evidence paints a picture of a violent environment in the solar system during the Hadean Eon 4.5 to 3.8 billion years ago, particularly through a cataclysmic event known as the Late Heavy Bombardment about 3.9 million years ago.

Although many believe the bombardment would have sterilized Earth, the new study shows it would have melted only a fraction of Earth’s crust, and that microbes could well have survived in subsurface habitats, insulated from the destruction.

“These new results push back the possible beginnings of life on Earth to well before the bombardment period 3.9 billion years ago,” Abramov said. “It opens up the possibility that life emerged as far back as 4.4 billion years ago, about the time the first oceans are thought to have formed.”

Full article here:

http://www.universetoday.com/2009/05/20/a-benevolent-sort-of-asteroid-bombardment/

Needless to say, this is good news for the chances of life appearing and surviving
on other planets throughout the Universe. Whether they eventually evolve enough
to create their own version of the Internet is another matter.