Kepler Exceeding Expectations

After only 43 days on the job, NASA's planet-hunting Kepler spacecraft has already found 706 possible candidates. So far, about 400 exoplanets have been discovered since 1994.

Kepler operates by looking for dips in starlight that could be caused by a planet moving across the disk of the star. Once Kepler finds a candidate. the possibility will be followed up by ground-based observatories, or by Hubble.

Kepler's goal is to find worlds similar to Earth. If all goes well, Kepler will be looking until November 2012. If the beginning is any indication, thousands of exoplanets might be identified. Whether any of them will be Earth-like, orbiting their parent star at a distance that would allow life to flourish, is another matter, but thousands of possibilities would argue strongly the planets are common in the universe.