Rise of the Super-Earths

Sat, 21 Jan 2012 16:00:00 +0000

We love our planet Earth. We should — it is our home, and there’s no place like home. There can’t ever be a better place than Earth. Plenty of serious science literature supports that view in an emotionally detached manner. It is often called the “Goldilocks hypothesis”: the Earth is just the right size (not too big, not too small) and just the right temperature (not too hot, not too cold) for life to emerge here. Life is a rare thing. Perched on our little planet, we can’t see any other out there, or at least not yet — so a certain dose of Earth-centrism seems justified. Or is it?

Life is extremely resilient once it takes hold, but it requires rich chemistry, large energy sources, and stability, right from the beginning. The comparative planetology of our Solar System makes it seem like those initial conditions are hard to come by. Earth seems perfect, whereas the rest have obvious defects. Mars is on the smallish side, lacks a substantial atmosphere and water, and is very cold (although we still hope to find life there). Jupiter is too big; its crushing pressures and element-poor environment make interesting chemistry impossible. The trouble with such a comparative analysis, however, is that it leaves out a crucial class of planets that, purely by happenstance, doesn’t occur in our Solar System.

Salon.com > Dimitar Sasselov

Rise of the Super-Earths