Thursday, January 10, 2008

Well that was lucky

Scientists: Earth Barely Supports Life

AUSTIN, Texas—If Earth had been slightly smaller and less massive, life might never have gained a foothold.

They key to life on Earth as we know it, scientists figure, is plate tectonics — the forces that move continents and build mountains. And the more massive a world is, the thinner its plates are...

"Plate tectonics are essential to life as we know it," said Diana Valencia of Harvard University... "Our calculations show that bigger is better when it comes to the habitability of rocky planets."

The study reveals Earth has been on the edge of habitability from the beginning, and just eked by to allow life-friendly conditions.
They say "super-Earths" up to ten times Earth's mass could be life-supporting. Bigger than that, and they become gas giants.

2 comments:

Sandi said...

And the more massive a world is, the thinner its plates are. Thinner plates are weaker and more easily moved and so able to support the kinds of crucial planet-shaping plate tectonics experienced on this planet over the billions of years that life evolved from simple one-celled organisms to complex creatures that can fly, swim and read.

Well I'm thinking that thinner, easily moved plates, would also produce more earthquakes and volcanos.

On the other hand thinner crusts probably wouldn't build up nearly as much pressure before slipping, causing quakes and volcanoes to be of lesser severity.

On the other other hand, there would probably be a lot more of them.

Sandi said...

Dang. I should proof read so I don't repeat myself.