Studying the Goldilocks planet

Much abuzz in the newsosphere and blogosphere about the discovery of a planet in the so-called "habitable zone" of another (fairly close by) star system: where given the right combination of water and atmosphere, the water would be liquid and the atmosphere would be present. Probably, at least. Thus, something could theoretically live there. The name of the planet is Gliese 581g (presumably it weighs more than that). I thought this article about how to study the planet to figure out if it really is a potential site for active exobiology was a good read:

If There's Life on Alien Planet Gliese 581g, How Do We Find It?

First things first: detect an atmosphere:

Life doesn't have to be intelligent and advanced for astronomers to pick it up. Studying Gliese 581g's atmosphere, for example, could theoretically reveal the presence of organisms as simple as microbes.

This method assumes the alien planet has an atmosphere, likely a necessity for life to take hold. Gliese 581g's discoverers reported that the planet's gravity is probably strong enough to hold onto an atmosphere, but they didn't definitively detect one.

"The first thing is, you've got to have an atmosphere," said Bill Borucki of NASA's Ames Research Center, the science principal investigator for NASA's planet-hunting Kepler mission. "If there is one, then what's the composition of that atmosphere?"