Big Earths

It hasn't received a lot of publicity, but there's a really cool thing up there in orbit. NASA's Kepler space observatory, launched last year, is busy staring at some 150,000 stars. It can measure dips in a star's brightness to one part in 10,000, and thus detect the passage of a planet across that star's surface. It will take several years - these studies are statistical - but the instruments already have detected new planets, and many more such finds are expected.

And think of this: while most "extrasolar" plants already discovered - some 450 of them - are Jupiter-size behemoths, more and more are not all that much bigger than the Earth. (Well, maybe 4 or 6 times. But, hey.)

What's interesting, however, is that theoretical geologic models suggest that a surprising number of them could be similar enough to Earth to support life.

In fact, the research shows, the Earth might be way down on the size-scale of life-supporting planets. We might not just be lucky enough to be on a planet the right distance from its sun, and one with the right mix of water and other elements, but one that is barely big enough.

The geological models are complicated, having to do with the more vigorous convection of bigger earths and their more speedy plate tectonics and subduction, hastening the carbon-silicate cycle, but the bottom line is that bigger earths could be even more hospitable to life than Earth-sized planets. And their larger masses would better hang on to their atmospheres and water.

Before long, scientists will be able to sample the light spectra of this sort of planet to detect the possibility of life.

This is good, because today I received an envelope in the mail that contained no outside indication of its source. But when I opened it, I learned that "The End of the World is Almost Here! HOLY GOD will bring Judgment Day on May 21, 2011."

Oh, poop.