NASA finds 706 Earth-like planets

NASA's Kepler spacecraft has found 706 planets that look like they could be similar to earth having gazed at some 156,000 stars in one small speck of the sky.

NASA scientists released data last week from the first first 43 days of Kepler's mission and they reveal that there may be many more potentially life-bearing planets in the universe than previously thought.

The Kepler space observatory watches stars for evidence of planets orbiting them - a potential give-away is regular changes in brightness of a star which may be caused by a planetary body passing in front of it. There are plenty of other possibilities of course, so the suggestion that all 706 candidates may be Earth-like planets will need some further investigation.

Kepler has its beady eye currently trained on a star field in the constellations Cygnus and Lyra.

"This is the most precise, nearly continuous, longest and largest data set of stellar photometry ever," David Koch, the mission's deputy principal investigator at NASA's Ames Research Center in California said in a statement. "The results will only get better as the duration of the data set grows with time." By measuring tiny decreases in the brightness of stars when planets cross – or transit – in front of them, astronomers can determine the size of the planet."

Astronomers are currently looking at 400 planet candidates that may be orbiting stars beyond our own solar system. They now have 706 more to study, using telescopes based on Earth as well as the Hubble Space Telescope and the Spitzer Space Telescope.

The Kepler observatory looks for Earth-like planets in the zone at a distance from far-off stars at which liquid water may exist on the surface of alien bodies.

"The Kepler observations will tell us whether there are many stars with planets that could harbour life, or whether we might be alone in our galaxy," said Kepler's science principal investigator William Borucki of NASA's Ames Research Center.