NASA's Kepler Space Telescope is dead. Long live Kepler.

All good things must come to an end, on Earth and even in space. 

NASA announced on Tuesday that the Kepler mission — which has transformed how we understand planets outside of our solar system — is officially over.

According to the space agency, Kepler has run out of fuel in space, ending its 9.5-year planet hunting mission.

"Before we launched Kepler, we didn't know if planets were common or rare in our galaxy," Paul Hertz, NASA's Astrophysics Division director, said in a press call Tuesday.

Thanks to Kepler's data, which was all safely beamed back to Earth before the end of the mission, we now know that planets are, in fact, exceedingly common.  Read more...