By Barry Eitel

SAN FRANCISCO

NASA announced Tuesday that its Kepler space telescope has discovered 1,284 new planets, the largest collection of new planets in history.

The new findings bring the total of verified exoplanets, meaning planets that orbit a star besides the sun, discovered by Kepler to 2,325.

The new exoplanets were found through analyzing batches of data that Kepler, launched into space in 2009, beamed back to Earth last July.

Of the 4,302 potential planets identified, astronomers claim that 1,284 have at least a 99 percent probability of being a planet, which is how NASA defines planet.

“Before the Kepler space telescope launched, we did not know whether exoplanets were rare or common in the galaxy,” said Paul Hertz, the astrophysics division director at NASA. “Thanks to Kepler and the research community, we now know there could be more planets than stars.

This knowledge informs the future missions that are needed to take us ever-closer to finding out whether we are alone in the universe.”

Analysts identified 550 rocky planets orbiting alien stars that are close in size to the Earth.

Of those, nine are in the “habitable zone” of their stars, meaning they orbit at a distance that is similar to the distance between the Earth and the sun. This means the exoplanets’ surface temperatures would allow liquid water to pool.

“Planet candidates can be thought of like bread crumbs,” according to lead author Timothy Morton of Princeton University. “If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you're going to need a broom. This statistical analysis is our broom.”

Kepler works by imaging one section of the sky that includes more than 150,000 stars. By pouring over this data, scientists can discover likely planets.

A report on the analysis was published Tuesday in The Astrophysical Journal.