This thread is intended for comments and questions regarding the Kepler
mission and the updates published under the topic: NASA's Kepler to find Earth-size planets
Kepler is a spaceborne telescope designed to search the nearby region of our galaxy for Earth-size planets orbiting in the habitable zone of stars like our sun. The habitable zone is the region around a star where temperatures permit water to be liquid on a planet's surface.
Liquid water is considered essential for the existence of life as we know it. The vast majority of the approximately 300 planets known to orbit other stars are much larger than Earth, and none is believed to be habitable.
The challenge for Kepler is to look at a large number of stars in order to statistically estimate the total number of Earth-size planets orbiting sun-like stars in the habitable zone. Kepler will survey more than 100,000 stars in our galaxy.