Transit graph

Kepler measures the brightness of stars. The data will look like an EKG showing the heart beat. Whenever a planet passes in front of its parent star as viewed from the spacecraft, a tiny pulse or beat is produced. From the repeated beats we can detect and verify the existence of Earth-size planets and learn about the orbit and size of the planet.
The scientific data from Kepler come in a different way than most astronomy missions. The Kepler spacecraft will not produce pretty pictures or even colorful spectrograms, but rather light curves derived from brightness changes collected from transits.
Credit: NASA Ames and Dana Berry