Kepler is the firsttelescope to be designed to findEarth-sized planets that orbit in the "habitablezone" where temperaturesare neither too hot nor too cold for water to remain inits liquid state.
This past December, for example, NASA's Kepler space telescope confirmed its first planet in the habitable zone, a "super Earth" known as Kepler-22b that's thought to be 2.4 times as wide as our planet.