NASA Telescope Confirms Alien Planet in Habitable Zone   
   By Mike Wall, SPACE.com Senior Writer   
   Space.com | SPACE.com - 18 hrs ago   
   This story was updated at 12:15 p.m. ET.   
       
   MOUNTAIN VIEW, Calif. - NASA's planet-hunting Kepler spacecraft has confirmed   
   the discovery of its first alien world in its host star's habitable zone -   
   that just-right range of distances that could allow liquid water to exist -   
   and found more than 1,000 new explanet candidates, researchers announced today   
   (Dec. 5).   
       
   The new finds bring the Kepler space telescope's total haul to 2,326 potential   
   planets in its first 16 months of operation.These discoveries, if confirmed,   
   would quadruple the current tally of worlds known to exist beyond our solar   
   system, which recently topped 700.   
       
   The potentially habitable alien world, a first for Kepler, orbits a star very   
   much like our own sun. The discovery brings scientists one step closer to   
   finding a planet like our own - one which could conceivably harbor life,   
   scientists said.   
       
   "We're getting closer and closer to discovering the so-called 'Goldilocks   
   planet,'" Pete Worden, director of NASA's Ames Research Center in Moffett   
   Field, Calif., said during a press conference today. [Gallery: The Strangest   
   Alien Planets]   
       
   The newfound planet in the habitable zone is called Kepler-22b. It is located   
   about 600 light-years away, orbiting a sun-like star.   
       
   Kepler-22b's radius is 2.4 times that of Earth, and the two planets have   
   roughly similar temperatures. If the greenhouse effect operates there   
   similarly to how it does on Earth, the average surface temperature on   
   Kepler-22b would be 72 degrees Fahrenheit (22 degrees Celsius).   
   Hunting down alien planets   
       
   The $600 million Kepler observatory launched in March 2009 to hunt for   
   Earth-size alien planets in the habitable zone of their parent stars, where   
   liquid water, and perhaps even life, might be able to exist.   
       
   Kepler detects alien planets using what's called the "transit method." It   
   searches for tiny, telltale dips in a star's brightness caused when a planet   
   transits - or crosses in front of - the star from Earth's perspective,   
   blocking a fraction of the star's light.   
       
   The finds graduate from "candidates" to full-fledged planets after follow-up   
   observations confirm that they're not false alarms. This process, which is   
   usually done with large, ground-based telescopes, can take about a year.   
       
   The Kepler team released data from its first 13 months of operation back in   
   February, announcing that the instrument had detected 1,235 planet candidates,   
   including 54 in the habitable zone and 68 that are roughly Earth-size.   
       
   Of the total 2,326 candidate planets that Kepler has found to date, 207 are   
   approximately Earth-size. More of them, 680, are a bit larger than our planet,   
   falling into the "super-Earth" category. The total number of candidate planets   
   in the habitable zones of their stars is now 48.   
       
   To date, just over two dozen of these potential exoplanets have been   
   confirmed, but Kepler scientists have estimated that at least 80 percent of   
   the instrument's discoveries should end up being the real deal.   
       
   More discoveries to come   
       
   The newfound 1,094 planet candidates are the fruit of Kepler's labors during   
   its first 16 months of science work, from May 2009 to September 2010. And they   
   won't be the last of the prolific instrument's discoveries.   
       
   "This is a major milestone on the road to finding Earth's twin," Douglas   
   Hudgins, Kepler program scientist at NASA headquarters in Washington, D.C.,   
   said in a statement.   
       
   Mission scientists still need to analyze data from the last two years and on   
   into the future. Kepler will be making observations for a while yet to come;   
   its nominal mission is set to end in November 2012, but the Kepler team is   
   preparing a proposal to extend the instrument's operations for another year or   
   more.   
       
   Kepler's finds should only get more exciting as time goes on, researchers say.   
       
   "We're pushing down to smaller planets and longer orbital periods," said   
   Natalie Batalha, Kepler deputy science team lead at Ames.   
       
   To flag a potential planet, the instrument generally needs to witness three   
   transits. Planets that make three transits in just a few months must be pretty   
   close to their parent stars; as a result, many of the alien worlds Kepler   
   spotted early on have been blisteringly hot places that aren't great   
   candidates for harboring life as we know it.   
       
   Given more time, however, a wealth of more distantly orbiting - and perhaps   
   more Earth-like - exoplanets should open up to Kepler. If intelligent aliens   
   were studying our solar system with their own version of Kepler, after all, it   
   would take them three years to detect our home planet.   
       
   "We are getting very close," Batalha said. "We are homing in on the truly   
   Earth-size, habitable planets."   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.64   
    * Origin: NCS BBS (1:3828/7)