Monday, September 07, 2009

Hm. Earth's size 'just right for life'

Pound360 is a big fan of New Scientist, but a recent headline has us scratching our heads. The headline: "Earth-sized planets are just right for life." The idea: Earth is the perfect size for plate tectonics (which helps regulate atmospheric carbon) and supporting a magnetic field (which shields the surface from life-threatening cosmic radiation).

So what's the problem?

First of all, have we studied enough rocky planets or planets with life to make a call like this? Second, what about Venus? Venus is the size of Earth, but there's no life. And third, Mercury. Mercury is about a third the size of Earth, but it
has a magnetic field.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.