Is there life on other planets? NASA's newest mission hopes to shed light on this question. Last Friday, NASA launched the Kepler Mission, a spacecraft-based telescope that will enable scientists to search a small area of the Milky Way for earth-like planets, capable of supporting life.
At the heart of the mission is the Kepler telescope. The telescope contains a very sensitive photometer, capable of measuring very small changes in light intensity. By continuously monitoring the light being emitted by over 100,000 stars, it can detect a subtle "dimming" of a given star's light if an orbiting planet passes in front (view a graphic of the "transit method" for detecting planets).
The mission's goal is to identify planets in the "habitable zone," the distance from a star where a planet is likely to have liquid water present. Once a planet is detected, NASA researchers will use information including the planet's period (the time it takes to orbit the star), the star's temperature and mass, and the planet's mass to calculate the planet's surface temperature.
For the next several months, Kepler will travel to its final vantage point: a carefully-calculated, unobstructed orbit around the sun. From there, Kepler's three-and-a-half year unblinking gaze will begin.