December 10, 2007


Meteor Pelting May Have Triggered Plate Tectonics (Larry O'Hanlon, 12/10/07, Discovery News)

The continuous overturning, melting and re-casting of Earth's crust over the eons may have started with a massive asteroid impact in Earth's infancy, suggests one geologist.

The unusual and iconoclastic hypothesis, if true, could help point the way to how and why plate tectonics did or did not get started on other worlds in our solar system and beyond. That's important because one of the critical ingredients of life on Earth is a constantly recycling crust.

"Everyone argues about when (plate tectonics) starts, but never asks about outside processes," said geologist Vicki Hansen of the University of Minnesota at Duluth.

If only you had a nickel for every scientific mystery that's explained by external intervention.

Posted by Orrin Judd at December 10, 2007 3:54 PM

This does not even start to explain what keeps the plates moving and why they move in different directions.

Posted by: jd watson at December 10, 2007 9:17 PM

I thought it was at least somewhat well-accepted now that the early earth was smacked by a Mars-sized (!!) rock, and that the freakishly precise dynamics of the collision resulted in formation of the Earth's bizarrely oversized moon.

With typical astronomer humor, this is apparently referred to as The Big Whack.

Posted by: Mike Earl at December 11, 2007 4:58 PM
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