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 silhouettes

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.

As 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.

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.

They would use the one-four-hundredth of the night sky that Kepler is looking at and extrapolate from there.

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 galaxy

Scientists  figured 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.

And that'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.

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

For many years scientists figured there were 100 billion stars in the Milky Way, 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't part of it.

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