ADN

NASA Telescope Confirms Alien Planet in Habitable Zone



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."

Absolutely Huge...Bookmarking this in hopes to see updates!

Planet in sweet spot of Goldilocks zone for life



WASHINGTON (AP) — A newly discovered planet is eerily similar to Earth and is sitting outside Earth's solar system in what seems to be the ideal place for life, except for one hitch. It is a bit too big.

The planet is smack in the middle of what astronomers call the Goldilocks zone, that hard to find place that is not too hot, not too cold, where water, which is essential for life, does not freeze or boil. And it has a shopping mall-like surface temperature of near 72 degrees, scientists say.

The planet's confirmation was announced Monday by NASA along with other discoveries by its Kepler telescope, which was launched on a planet-hunting mission in 2009.

That is the first planet confirmed in the habitable zone for Kepler, which already had found Earth-like rocky planets elsewhere. Twice before astronomers have announced a planet found in that zone, but neither has been as promising.

"This is a phenomenal discovery in the course of human history," Geoff Marcy of University of California, Berkeley, one of the pioneers of planet-hunting outside Earth's solar system, said in an email. "This discovery shows that we Homo sapiens are straining our reach into the universe to find planets that remind us of home. We are almost there."

The new planet, named Kepler-22b, has key aspects it shares with Earth. It circles a star that could be the twin of Earth's sun and at just about the same distance. The planet's year of 290 days is even close to Earth's. It probably has water and rock.

The only trouble is the planet's a bit big for life to exist on the surface. The planet is about 2.4 times the size of Earth. It could be more like the gas-and-liquid Neptune with only a rocky core and mostly ocean.

"It's so exciting to imagine the possibilities," said Natalie Batalha, the Kepler deputy science chief.

Floating on that "world completely covered in water" could be like being on an Earth ocean and "it's not beyond the realm of possibility that life could exist in such an ocean," Batalha said in a phone interview.

Kepler cannot find life itself, just where the conditions might be right for it to thrive. And when astronomers look for life elsewhere, they are talking about everything ranging from microbes to advanced intelligence that can be looking back at us.

So far the Kepler telescope has spotted 2,326 candidate planets outside Earth's solar system with 139 of them potentially habitable ones. Even though the confirmed Kepler-22b is a bit big, it is smaller than most of the other candidates. It is closest to Earth in size, temperature and star than either of the two previously announced planets in the zone.

The confirmation of one of two, though, has been disputed. The latest discovery has been confirmed several ways, including by two other telescopes.

This year, a European team of astronomers said they had confirmed another planet in the habitable zone, but that one was hot and barely on the inside edge of the habitable zone.

For Marcy, who is on the Kepler team, the newest planet is a smidgen too large. But, "that smidgen makes all the difference," he said.

Because its size implies that it is closer to Neptune in composition than Earth, "I would bet my telescope that there is no hard, rocky surface to walk on," Marcy said.

Chief Kepler scientist William Borucki said he thinks the planet is somewhere between Earth and gas-and-liquid Neptune, but that it has a lot of rocky material. It is in a size range that scientists do not really know anything about. Measurements next summer may help astronomers have a better idea of its makeup, he said.

The planet is 600 light years away. Each light year is 5.9 trillion miles. It would take a space shuttle about 22 million years to get there.

Kepler spots a planet when it passes in front of its star. NASA requires three of those sightings before it begins to confirm it as a planet. Borucki said the third sighting for 22b happened a year ago, just before the telescope shut down for a while. It took several months to finish the confirmation.

"It's a great gift," Borucki said. "We consider this sort of our Christmas planet."