Washington (ISJ): US Astronomers discovered an earth-sized planet, orbiting a star in the 'habitable zone' of stars. �The discovery of Kepler-186f, confirms that planets the size of Earth exist in the habitable zone of stars other than the Sun. Unlike planets found earlier in the habitable zone, Kepler-186f is similar to Earth in size.� � "The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth," said Paul Hertz, Director of NASA's Astrophysics Division in Washington.
"Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind's quest to find truly Earth-like worlds." � Although the size of Kepler-186f is known, its mass and composition are not. Earlier research, however, suggests that a planet the size of Kepler-186f is likely to be rocky. It is in the Kepler-186 system, about 500 light-years from Earth in the constellation Cygnus. The system is also home to four companion planets, which orbit a star half the size and mass of Sun.� � "We know of just one planet where life exists - Earth. When we search for life outside our solar system we focus on finding planets with characteristics that mimic that of Earth," said Elisa Quintana, research scientist at the SETI Institute at NASA's Ames Research Center in Calif. "Finding a habitable zone planet comparable to Earth in size is a major step forward." � Kepler-186f orbits its star once every 130-days and receives one-third the energy from its star that Earth gets from the sun, placing it nearer the outer edge of the habitable zone. On the surface of Kepler-186f, the brightness of its star at high noon is only as bright as the Sun appears to us about an hour before sunset. � The next step in the search for distant life includes looking for true Earth-twins -- Earth-size planets orbiting within the habitable zone of a sun-like star and measuring their chemical compositions. The Kepler Space Telescope, which simultaneously and continuously measured the brightness of more than 150,000 stars, is NASA's first mission capable of detecting Earth-size planets around stars like our sun. - See more at: http://www.indiansciencejournal.com/science-detail.php?m_id=135#sthash.MIICerAP.dpuf