Earth-Size Planet Found In The 'Habitable Zone' of Another Star   
       
   April 17, 2014: Using NASA's Kepler Space Telescope, astronomers have   
   discovered the first Earth-size planet orbiting in the "habitable zone" of   
   another star. The planet, named "Kepler-186f" orbits an M dwarf, or red dwarf,   
   a class of stars that makes up 70 percent of the stars in the Milky Way   
   galaxy. The discovery of Kepler-186f confirms that planets the size of Earth   
   exist in the habitable zone of stars other than our sun.   
       
   The "habitable zone" is defined as the range of distances from a star where   
   liquid water might pool on the surface of an orbiting planet. While planets   
   have previously been found in the habitable zone, the previous finds are all   
   at least 40 percent larger in size than Earth and understanding their makeup   
   is challenging. Kepler-186f is more reminiscent of Earth.   
       
   http://tinyurl.com/p9z7kkv   
       
   The artist's concept depicts Kepler-186f , the first validated Earth-size   
   planet to orbit a distant star in the habitable zone.  More   
       
   Kepler-186f orbits its parent M dwarf star once every 130-days and receives   
   one-third the energy 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 our sun appears to us about an hour   
   before sunset.   
       
   "M dwarfs are the most numerous stars," said Elisa Quintana, research   
   scientist at the SETI Institute at NASA's Ames Research Center in Moffett   
   Field, Calif., and lead author of the paper published today in the journal   
   Science. "The first signs of other life in the galaxy may well come from   
   planets orbiting an M dwarf."   
       
   However, "being in the habitable zone does not mean we know this planet is   
   habitable," cautions Thomas Barclay, a research scientist at the Bay Area   
   Environmental Research Institute at Ames, and co-author of the paper. "The   
   temperature on the planet is strongly dependent on what kind of atmosphere the   
   planet has. Kepler-186f can be thought of as an Earth-cousin rather than an   
   Earth-twin. It has many properties that resemble Earth."   
       
   Kepler-186f resides in the Kepler-186 system, about 500 light-years from Earth   
   in the constellation Cygnus. The system is also home to four companion   
   planets: Kepler-186b, Kepler-186c, Kepler-186d, and Kepler-186e, whiz around   
   their sun every four, seven, 13, and 22 days, respectively, making them too   
   hot for life as we know it. These four inner planets all measure less than 1.5   
   times the size of Earth.   
       
   http://tinyurl.com/ockqtns   
       
   The diagram compares the planets of our inner solar system to Kepler-186, a   
   five-planet star system about 500 light-years from Earth in the constellation   
   Cygnus.  More   
       
   Although the size of Kepler-186f is known, its mass and composition are not.   
   Previous research, however, suggests that a planet the size of Kepler-186f is   
   likely to be rocky.   
       
   "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.   
       
   The next steps in the search for distant life include looking for true   
   Earth-twins -- Earth-size planets orbiting within the habitable zone of a   
   sun-like star -- and measuring the 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.   
       
   Looking ahead, Hertz said, "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."   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   Ames is responsible for Kepler's ground system development, mission   
   operations, and science data analysis. NASA's Jet Propulsion Laboratory in   
   Pasadena, Calif., managed Kepler mission development. Ball Aerospace &   
   Technologies Corp. in Boulder, Colo., developed the Kepler flight system and   
   supports mission operations with the Laboratory for Atmospheric and Space   
   Physics at the University of Colorado in Boulder. The Space Telescope Science   
   Institute in Baltimore archives, hosts and distributes Kepler science data.   
   Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science   
   Mission Directorate.   
       
   The SETI Institute is a private, nonprofit organization dedicated to   
   scientific research, education and public outreach.  The mission of the SETI   
   Institute is to explore, understand and explain the origin, nature and   
   prevalence of life in the universe.   
       
   For more information about the Kepler mission, visit: http://www   
   nasa.gov/kepler   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)