Extrasolar planet news

One of my more... obscure interests is the science surrounding planets orbiting other stars. A bit of news this week.

First, we have the discovery of water vapor in the atmosphere of a "hot jupiter" planet, romantically named HD209458b. Not really Earth-shattering, but an interesting discovery nonetheless.

Up next, a NASA scientists says that plants on other planets might not be green, instead absorbing different parts of the light spectrum. The basis for this? An answer to the question of why grass is green:

It turns out that more red light reaches plants on Earth, and blue light is the easiest to absorb. So plants make most efficient use of these two, and that leaves green light as largely superfluous.

So if you had a star that emitted more light in a different part of the spectrum, plants would conceivably evolve to absorb different levels of light. (Are there examples of, say, blue-colored photosynthesis on Earth? That is, plants that do in fact absorb red and green while reflecting blue?)

Finally, this is an interesting idea: a group of scientists has published a paper arguing that M-class (Red) stars may be more hospitable to life than previously believed. There are a number of obstacles that life would overcome: M stars are dimmer, so the planet would need to be so close to the star that it would become tidally-locked, like the moon around the Earth. This would mean one side would always be in daylight, and the early thinking was that this simply made life impossible. New models suggest that an atmosphere no thicker than the Earth's would be enough to regulate the temperature and allow liquid water to exist on the surface.

If true, this dramatically increases the number of candidate stars where life could form -- M stars make up about 75% of the Milky Way galaxy. And M dwarf stars are dramatically long-lived to boot:

'One...aspect of M dwarfs makes them intriguing for SETI: they may be ideal hosts for advanced technological civilizations because they live an extraordinarily long time. Stars like the Sun live (i.e., they fuse hydrogen into helium) for only about 10 billion years. No M dwarf that ever formed has yet to die; no M dwarf will die for more than another 100 billion years. With such long lifetimes, there are big possibilities for these small stars.'

And you'll have to pardon me for being a bit tantalized by the fact that our Sun's nearest neighbor is Proxima Centauri, an M-class dwarf.

Giordano Bruno is owed an apology.