NASA's Kepler discovers 715 new planets

NASA's Kepler mission has announced the discovery of 715 new planets.

These newly-verified worlds orbit 305 stars, revealing multiple-planet systems much like our own solar system.

Nearly 95 percent of these planets are smaller than Neptune, which is almost four times the size of Earth.

This discovery marks a significant increase in the number of known small-sized planets more akin to Earth than previously identified exoplanets, which are planets outside our solar system.

"The Kepler team continues to amaze and excite us with their planet hunting results," John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington, said.

"That these new planets and solar systems look somewhat like our own, portends a great future when we have the James Webb Space Telescope in space to characterize the new worlds," he said.

Since the discovery of the first planets outside our solar system roughly two decades ago, verification has been a laborious planet-by-planet process.

Now, scientists have a statistical technique that can be applied to many planets at once when they are found in systems that harbor more than one planet around the same star.

To verify this bounty of planets, a research team co-led by Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, Calif., analyzed stars with more than one potential planet, all of which were detected in the first two years of Kepler's observations-May 2009 to March 2011.

The findings are set to be published in The Astrophysical Journal.