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WASHINGTON – Scientists have estimated the prototypal cosmic counting of planets in our accumulation and the drawing are astronomical: at diminutive 50 1000000000 planets in the Milky Way.

At diminutive 500 million of those planets are in the not-too-hot, not-too-cold regularize where chronicle could exist. The drawing were extrapolated from the primeval results of NASA's planet-hunting uranologist telescope.

Kepler science honcho William Borucki says scientists took the sort of planets they institute in the prototypal assemblage of intelligent a diminutive conception of the period sky and then made an judge on how probable stars are to have planets. uranologist symptom planets as they transfer between Earth and the grapheme it orbits.

So farther uranologist has institute 1,235 candidate planets, with 54 in the Goldilocks zone, where chronicle could possibly exist. Kepler's main assignment is not to examine individualist worlds, but give astronomers a sense of how many planets, especially potentially habitable ones, there are probable to be in our galaxy. They would use the one-four-hundredth of the period sky that uranologist is hunting at and extrapolate from there.

Borucki and colleagues figured digit of digit stars has planets and digit of 200 stars has planets in the habitable zone, announcing these ratios Sat at the American Association for the Advancement of Science period conference in Washington. And that's a peak because these stars crapper have more than digit follower and uranologist has yet to intend a long enough glimpse to wager planets that are boost out from the star, same Earth, Borucki said.

For example, if uranologist were 1,000 reddened years from Earth and hunting at our solarise and noticed Venus passing by, there's only a one-in-eight chance that Earth would also be seen, astronomers said.

To intend the judge for the total sort of planets, scientists then took the oftenness observed already and practical it to the sort of stars in the Milky Way.

For many years scientists figured there were 100 1000000000 stars in the Milky Way, but last assemblage a Yale individual figured the sort was fireman to 300 1000000000 stars.

Either way it shows that Carl Sagan was correct when he talked of zillions and zillions of worlds, said old NASA astronomer Steve Maran, who praised the research but wasn't conception of it.

And that's meet our galaxy. Scientists amount there are 100 1000000000 galaxies.

Borucki said the new calculations advance to worlds of questions about chronicle elsewhere in the cosmos. "The incoming question is ground haven't they visited us?"

And the answer? "I don't know," Borucki said.

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Online:

Kepler site: http://kepler.nasa.gov/

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