The Kepler Mission

 This chart compares artist's concept images of the first Earth-size planets found around a sun-like star to planets in our own solar system, Earth and Venus.
The image above shows a size comparison of the exoplanets Kepler-20e and Kepler 20f with Venus and Earth.Image courtesy of NASA/Ames/JPL-Caltech.

The Kepler Mission is NASA’s first mission capable of finding Earth-size and smaller planets around other stars using an orbiting space telescope. The Kepler Space Telescope has been monitoring 100,000 stars similar to our Sun since its launch in March 2009. The Kepler Space Telescope, named for astronomer Johannes Kepler, looks for planets orbiting stars by looking for changes in a star’s brightness.

Kepler’s primary mission is to find Earth-size exoplanets. Detecting the massive gas giant exoplanets – called Super Jupiters – has been relatively easy with other methods. So the Kepler Space Telescope watches transits and measures the reduction in the star’s light due to the planet transiting in front of its star.

This image shows a size comparison of the exoplanets Kepler-20e and Kepler 20f with Venus and Earth.