The possibility of alien life has captivated our imaginations for generations. Now that possibility just got a big boost as Kepler's managed to find and confirm a potentially Earth-like planet. It's just 600 light years away and occupies that magic 'habitable zone' around its star, like the Earth does around the sun.
Kepler-22b is 2.4 times the size of Earth, has a 290-day orbit around its star, which itself is G-class -- a bit cooler and smaller than our own G2V-class Sun. We don't know much else about the planet, it could be mostly gas for all we know at this stage, but it's the first confirmed habitable zone planet.
Kepler's mission is to search for planets that may contain life -- at least as we know it -- as defined by criteria that include the possibility of water and a suitable temperature, balanced by distance to a star and potential atmosphere. Currently it's found 54 potential candidates, but Kepler-22b is the first to actually be confirmed as a planet. Hopefully we'll see more confirmed in the next couple of years. But let's hope if they do contain life, they end up being more Vulcan than Independence Day-type aliens. I quite like living, and on Earth for that matter. No stinking alien is going to take that away from me without a puny, insignificant fight. [NASA via Geek]