715 New Planets Discovered By Kepler; Five Are Nearly Earth-Sized, Orbiting In Habitable Zone

NASA's Kepler telescope discovered 715 planets orbiting 305 stars.

About 95 percent of the newly-discovered planets are smaller than Neptune, a NASA news release reported.

"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 in the news release. "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."

In order to make the finding the researchers looked at stars that were good candidates for hosting more than one planet. The team used a technique called "verification by multiplicity" that employs probability.

Kepler looked at 150,000 stars, and found a few thousand of those were planet candidates; hundreds of these stars are believed to host multiple planets. Through this technique the researchers identified 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," Jack Lissauer, planetary scientist at NASA's Ames Research Center, said in the news release. "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."

In the future the researchers hope to take a closer look at all of these planets. The team already knows that four of the planets are less than 2.5 times the size of Earth and orbit within the "habitable zone" of their host stars; this mean these planets could harbor water and even extraterrestrial life.

One of these possible-habitable planets, dubbed Kepler-296f, orbits a star only five percent as bright as the Sun and is twice the size of Earth.

"From this study we learn planets in these multi-systems are small and their orbits are flat and circular -- resembling pancakes -- not your classical view of an atom," Jason Rowe, research scientist at the SETI Institute in Mountain View, Calif., and co-leader of the research, said in the news release. "The more we explore the more we find familiar traces of ourselves amongst the stars that remind us of home."