The most Earth-like planet ever discovered is circling a star 600 light years away, a key finding in an ongoing quest to learn if life exists beyond Earth, scientists said on Monday.
The planet, called Kepler-22b, joins a list of more than 500 planets found to orbit stars beyond our solar system. It is the smallest and the best positioned to have liquid water on its surface -- among the ingredients necessary for life on Earth.
We are homing in on the true Earth-sized, habitable planets," said San Jose State University astronomer Natalie Batalha, deputy science team lead for NASA's Kepler Space Telescope that discovered the star.
The telescope, which was launched three years ago, is staring at about 150,000 stars in the constellations Cygnus and Lyra, looking for faint and periodic dimming as any circling planets pass by, relative to Kepler's line of sight.
Results will be extrapolated to determine the percentage of stars in the Milky Way galaxy that harbor potentially habitable, Earth-size planets.
This is the first detection of a potentially habitable world orbiting a Sun-like star, scientists reported in findings to be published in The Astrophysical Journal.
Kepler-22b is 600 light years away. A light year is the distance light travels in a year, about 6 trillion miles (10 trillion km).