Since its launch in
2009, the Kepler space telescope has been watching more than 150,000
stars. The telescope is set to detect any small disruptions to any
star's light made by planets orbiting around them, and today NASA
announced they have confirmed a new planet - dubbed Kepler 22-b - which
resides in the so-called habitable zone of its star about 600 light
years away from Earth. Kepler 22-b is about 2.4 times the size of Earth and
its average temperature is 22 degrees Celsius (71.6 F), making it
theoretically possible to support life.
Kepler 22-b is just one of 2,326 "candidate" planets discovered by
the telescope of which 54 are believed to orbit in a habitable zone
around a star. The habitable zone is shorthand for the proximity of the
planet to the star (see image below) so that the surface temperature is
neither too hot or too cold to support life. When the dip in the star's
light is observed by the Kepler telescope, the team then confirms its
existence with other telescopes, a process that can take years of
observations.
"Fortune smiled upon us with the detection of this planet," said
William Borucki from NASA's Ames Research Center. "The first transit was
captured just three days after we declared the spacecraft operationally
ready. We witnessed the defining third transit over the 2010 holiday
season."
Kepler 22-b is 15 percent closer to its sun than Earth is to ours, so
its year is approximately 290 days. Its sun shines about 25 percent
weaker, however, meaning the 70 degree F temperature would support water
in a liquid form.