NASA discovers first earth-sized planet in habitable zone

In search for life on other planets, NASA astronomers have detected an earth-like planet orbiting the habitable zone of a cool star.

Using the planet-hunting NASA's Kepler Space Telescope, researchers identified the planet as Kepler-186f that is 1.11 times the radius of the earth.

"The discovery of Kepler-186f is a significant step toward finding worlds like our planet earth," said Paul Hertz, NASA's astrophysics division director at the agency's headquarters in Washington, DC.

Kepler-186f is part of a multi-planet system around the star Kepler-186 which has five planets, one of which is in the center of the habitable zone.

"We know of just one planet where life exists - earth. Finding a habitable zone planet comparable to earth in size is a major step forward," added lead author Elisa Quintana, a research scientist at the SETI Institute at NASA's Ames Research Center in Moffett Field, California.

The host star, Kepler 186, is an M1-type dwarf star which means it would burn hydrogen forever, so there is ample opportunity to develop life around this particular star.

"The intensity and spectrum of radiation from Kepler-186f indicate that the planet could have an earth-like atmosphere and water at its surface which is likely to be in liquid form," revealed co-author Justin R. Crepp, a professor of physics from University of Notre Dame in Australia.

The next steps in the search for distant life include looking for true earth-twins and measuring their chemical compositions, said the study published in the journal Science.