Photo: Kepler Space Telescope
NASA said that astronomers working with the Kepler Space Telescope have located the first Earth-sized planet within what is called the habitable zone: the right distance from a star to allow liquid water to pool on its surface.
Dubbed Kepler-186f, the planet is some 500 light-years from Earth in the constellation Cygnus.
The exoplanet was first spotted with the Kepler Space Telescope and the find was confirmed by observations from the W.M. Keck and Gemini Observatories in Hawaii.
“When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth,” Elisa Quintana, research scientist at the SETI Institute at NASA’s Ames Research Center in California, said.
“Finding a habitable zone planet comparable to Earth in size is a major step forward,” said Quintana, lead author of a paper on Kepler-186f published in the journal Science.
Previously discovered habitable-zone exoplanets were all a minimum of 40 percent larger than Earth, NASA said.
The Kepler Space Telescope, which was launched in March 2009 and orbits the Sun at a distance of 149.5 million kilometers (92.89 million miles) from the Earth, has discovered 715 planets outside our solar system, NASA said in February.