At 10:48 PM EST Nasa’s Kepler telescope will launch. The Kepler mission focuses on finding other Earth-sized planets. It takes a very broad snapshot of the sky, compared to something like Hubble, and instead of taking pi ctures, it uses the transit method. How it works: watch a star for a very long time. If the starlight dims momentarily, we know a planet passed in front of it, and we’re able to measure that dip in brightness and find the size of the planet. This is the first time that photometry has ever been done on this scale, with this many stars. We may be able to learn whether planets like ours are rare or common in the galaxy — and how likely it is that some contain water, and, perhaps, life. Some webcasts here.