AUSTIN, Texas—If Earth had been slightly smaller and less massive, life might never have gained a foothold.They say "super-Earths" up to ten times Earth's mass could be life-supporting. Bigger than that, and they become gas giants.
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.
Thursday, January 10, 2008
Well that was lucky
Scientists: Earth Barely Supports Life