In search of aliens: NASA picture shows 1,235 planets that could house extra-terrestrial lifeforms

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If aliens exist, these are what their planets look like, according to NASA.Astronomers at the U.S. space department have spent the last two years scouring the Milky Way for Earth-like planets in their quest for foreign life forms.And this is what they have come up with. The black spots represent 1,235 planets orbiting their suns, which have been arranged by order of size.

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Alien home? The black spots represent 1,235 planets orbiting their suns. As a point of reference, the lone planet on the right below the top row represents our sun, with Earth and Jupiter as tiny black silhouettesAs a point of reference, the lone planet on the right below the top row represents our sun, with Earth and Venus as tiny black silhouettes.Of these candidate planets, there are 54 where life could possibly exist in the 'Goldilocks Zone'.The 'Goldilocks Zone' is the distance from a star where an Earth-like planet can maintain liquid water and Earth-like life on its surface.

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Kepler'smain mission is not to examine individual worlds, but give astronomers asense of how many planets, especially potentially habitable ones, thereare likely to be in our galaxy.They would use the one-four-hundredth of the night sky that Kepler is looking at and extrapolate from there.

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Earth's eye view: 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 galaxyScientis! ts figur ed one of two stars has planets and one of 200 stars has planets in the habitable zone, announcing these ratios Saturday at the American Association for the Advancement of Science annual conference in Washington.
Andthat's a minimum because these stars can have more than one planet and Kepler has yet to get a long enough glimpse to see planets that are further out from the star, like Earth, Borucki said.
Forexample, if Kepler were 1,000 light years from Earth and looking at oursun and noticed Venus passing by, there's only a one-in-eight chance that Earth would also be seen, astronomers said.
To get the estimate for the total number of planets, scientists then took the frequency observed already and applied it to the number of stars in the Milky Way.
Formany years scientists figured there were 100 billion stars in the MilkyWay, but last year a Yale scientist figured the number was closer to 300 billion stars.Either way it shows that Carl Sagan was right when he talked of billions and billions of worlds, said retired NASA astronomer Steve Maran, who praised the research but wasn'tpart of it.

And that's just our galaxy. Scientists figure there are 100 billion galaxies.