NASA discovers 715 new planets outside solar system

The team used the technique called verification by multiplicity to analyse 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, and identified the 715 new planets.

"Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates -- but they were only candidate worlds," said Lissauer.

"We've now developed a process to verify multiple planet candidates in bulk to deliver planets wholesale, and have used it to unveil a veritable bonanza of new worlds."

Launched in March 2009, Kepler is the first NASA mission to find potentially habitable Earth-size planets. Discoveries include more than 3,600 planet candidates, of which 961 have been verified as bona-fide worlds.

The findings will be published March 10 in The Astrophysical Journal.