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Scientists have discovered a planet which may be similar to Earth, circling a star 600 light years away.
NASA's findings, the first detection of a potentially habitable world orbiting a Sun-like star, are due to be published in The Astrophysical journal.
It is a key finding in an ongoing quest to learn if life exists beyond Earth.
The planet, called Kepler-22b, is about 2.4 times the size of Earth.
Among 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 habitation.
A light year is the distance light travels in a year, about 6 trillion miles (10 trillion km).
