WASHINGTON — Scientists have estimated the first cosmic census of planets in our galaxy, and the numbers are astronomical: at least 50 billion planets in the Milky Way.
At least 500 million of those planets are in the not-too-hot, not-too-cold zone where life could exist. The numbers were extrapolated from the early results of NASA’s planet-hunting Kepler telescope.
Kepler science chief William Borucki said scientists took the number of planets they found in a year of searching a small part of the night sky and made an estimate on how likely stars are to have planets.
Kepler spots planets as they pass between Earth and the stars they orbit.
Kepler’s main mission is not to examine individual worlds but give astronomers a sense of how many planets, especially potentially habitable ones, there are likely to be in our galaxy.
