One down a few billion similar
planets to go...find. They are out there, and filled with humans just like us,
with shopping malls and everything else that makes life worth living, or
whatever. Granted, a disappointing thought, but there are far more exiting planets
out there too.
Lou 
http://news.yahoo.com/nasa-telescope-confirms-alien-planet-habitable-zone-162005358.html
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
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."
You can
follow SPACE.com senior writer Mike Wall on Twitter: @michaeldwall. Follow SPACE.com
