Telegraph, Chr. Sci. Monitor, Colorado papers: Our simplest ancestors might go back to BEFORE the world’s surface got creamed by asteroids
It is a fairly familiar speculation that Earth may have evolved life afresh several times. This is a corollary to the idea that, especially during a period called the Late Heavy Bombardment a few hundred million years or so after our planet congealed, asteroids and minor planets hitting Earth would have vaporized and jounced so much crust that any microbes etc. already in place would have been erased. The Moon’s ancient, pocked face still bears the scars.
Now in the news, reported by scientists at the University of Colorado, is an argument that a few of life’s terrestrial pioneers, living in the pores of our rocky crust thousands of feet down, could have survived that great pulverization some 3.9 billion years ago. Not only that, they believe, a proliferation of deep, boiling-water hot spots might have enhanced evolution during such tumult. The new study’s authors say the analysis implies our ancestry may go as far back as 4.4 billion years during a geologic period called the Hadean. That’s close to the solar system’s birth about 4.7 billion years past. The 4.4 figure reflects roughly the birth of oceans. Another factor is that 4.5 gigayears is about when the Moon congealed. The latter in turn followed no mere heavy bombardment. In the most accepted current theory the Moon grew from debris of the near-dismemberment of Earth by collision with a body the size of Mars. That, say some, might well melt and viciously stir things right down into the core.
Stories:
- Denver Post – Jennifer Brown : CU study: Asteroid may have aided life ; This is the source of the pic, too – with one CU researcher shown standing before a calculated, thermal map of how an asteroid-bombarded Earth may have appeared. Brown calls asteroids “giant, reckless rocks.” Nice.
- Boulder Daily Camera – Laura Snider: CU: LIfe on Earth could have survived asteroid bombardment – New study could push back the timeline for life on Earth ; A US university issues a science press release (maybe had a press conference too) and TWO local papers, in 2009!, wrote it well. Hurray.
- Christian Science Monitor – Pete Spotts (blog): Life’s foothold on Earth may reach back 4.4 billion years ;
- AFP: Scientists set back clock on origin of life ;
- Telegraph (UK) : Life on earth may have started 4.4 billion years ago, according to asteroid study ;
- Reuters – Julie Steenhuysen : Study turns back clock on origins of life on Earth ;
Grist for the Mill: U Colo – Boulder Press Release ;
-CP
