OT: Astronomy Picture of the Day

[Renegade 13]

I think it's more likely that large gas giants in close orbits have been discovered so far due mostly to the methods that we currently have to use to detect extra-solar planets. The most fruitful efforts detect minor gravitational perturbations that the planet induces in the parent star in order to detect the planets. This method will inherently favor discovery of large planets that are close in. Planets that are smaller or that are farther out will induce much smaller gravitational perturbations within the parent star, so will be much harder to detect with our current instruments...though hopefully the proposed TPF (Terrestrial Planet Finder) array will change that if it ever gets off the ground.