The launch of the Kepler telescope
A huge telescope has been blasted into space to search the galaxy for other planets, like Earth, which may be capable of supporting life.
The Kepler telescope will spend three and a half years checking out more than 100,000 stars to see if they're being orbited by Earth-like planets.
Scientists don't expect to find humans or animals living on the planets.
But they say some of them could show potential for supporting living things, like tiny bugs or bacteria.
For life to survive on other planets, scientists say it's all about something they're calling the Goldilocks effect.
That's because planets need to be the perfect distance from their star so they're not too hot or too cold for creatures to live on them.
The Kepler telescope will search for the planets by looking for any dimming of the light from the stars as planets pass between them and the spacecraft.
But it won't be easy.
James Fanson, who's managing the Kepler project, said: "Trying to detect Jupiter-size planets crossing in front of their stars is like trying to measure the effect of a mosquito flying by a car's headlight.
"Finding Earth-sized planets is like trying to detect a very tiny flea in that same headlight."