Image: Artist's rendering of planet
NASA Ames Research Center  /  AP
NASA's Kepler telescope is finding that relatively smaller planets — still larger than Earth, but tinier than Jupiter —are proving more common outside our solar system than once thought. This drawing is of one of the smallest planets that Kepler has found, a rocky planet called Kepler-10b, that measures 1.4 times the size of Earth and where the temperature is more than 2,500 degrees Fahrenheit.
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updated 2/2/2011 1:40:39 PM ET 2011-02-02T18:40:39

An orbiting NASA telescope is finding whole new worlds of possibilities in the search for alien life, spotting more than 50 potential planets that appear to be in the habitable zone.

In just a year of peering out at a small slice of the galaxy, the Kepler telescope has discovered 1,235 possible planets outside our solar system. Amazingly, 54 of them are seemingly in the zone that could be hospitable to life — that is, not too hot or too cold, Kepler chief scientist William Borucki said.

Until now, only two planets outside our solar system were even thought to be in the "Goldilocks zone." And both those discoveries are highly disputed.

Fifty-four possibilities is "an enormous amount, an inconceivable amount," Borucki said. "It's amazing to see this huge number because up to now, we've had zero."

The more than 1,200 newfound celestial bodies are not confirmed as planets yet, but Borucki estimates 80 percent of them will eventually be verified. Some think the figure may be even higher.

After confirmation, it's another big step to prove that a confirmed planet has some of the basic conditions needed to support life, such as the proper size, composition, temperature and distance from its star. More advanced aspects of habitability such as atmospheric conditions and the presence of water and carbon require telescopes that aren't built yet.

Just because a planet is in the habitable zone doesn't mean it has life. Mars is a good example of that. And even if some these planets are found to contain life, it may not be intelligent life; it could be bacteria or mold or some kind of life form people can't even imagine.

All the celestial bodies Kepler looks at are in our Milky Way galaxy, but they are so far away that traveling there is not a realistic option. In some cases it would take many millions of years with current technology.

But what Kepler is finding in distant parts of the galaxy could be applied to exploring closer stars, astronomers say. And there's always the chance that scientists could pick up the signatures of life in alien atmospheres using more sophisticated instruments, or even find innovative ways to make contact with faraway civilizations.

"Our grandchildren will have to decide what's the next step," Borucki said at a NASA news conference. "Do they want to go there? Do they want to send a robot?"

Worlds galore
Before Wednesday, the count of confirmed planets outside the solar system stood at 519. That means Kepler could triple the number. Those findings are from Kepler's scanning of just one-four-hundredth of the night sky, so the actual number of planets out there is presumably hundreds of times greater, Borucki said.

That is exciting to astronomers, since the more planets there are, the greater the odds that life exists elsewhere in the universe.

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Yale University astronomer Debra Fischer, who wasn't part of the Kepler team but serves as an outside expert for NASA, said the new information "gives us a much firmer footing" to hope for worlds that could harbor life.

Another outside astronomer, Lisa Kaltenegger of Harvard University, called the findings "exciting good news."

Kepler also found that there are many more relatively small planets than there are giant planets. That is encouraging, too: Astronomers think a planet needs to be solid — rocky like Earth or Mars — for life to develop. And very large planets are unlikely to be solid; they are more prone to be gas behemoths like Jupiter.

Sixty-eight of the planet candidates Kepler found are considered Earth-sized, including the first ones ever discovered to be smaller than Earth. An additional 288 planets were less than twice the size of Earth, which is still in that optimum zone for life.

Only five of the 54 potentially habitable celestial bodies are close to the size of Earth, while the rest approach the gassy girths of Neptune or Jupiter, Borucki said. Such gas giants shouldn't necessarily be ruled out as locales for life: It's possible that moons orbiting those planets could be habitable — like Pandora, the fictional moon of Prometheus in the movie "Avatar." Borucki even speculated that an alien civilization would welcome the variety.

"For your Christmas vacation you could go from one moon to another," he joked.

Real-estate values going up
To be in the habitable zone, a planet has to be the proper distance from its star so that it could have liquid water on its surface, at least sometimes. The proper distance varies by star; smaller, weaker stars, for example, would require planets to be closer to be habitable.

Because of the various factors that could make planets more prone to life, University of California Santa Cruz astronomer Greg Laughlin created a formula that puts a dollar value on these far-off planets, with the idea that the first planet that is incredibly similar to Earth would have a value of $1 million.

Until Wednesday, the highest value Laughlin assigned to an exoplanet, which is what astronomers call a planet outside our solar system, was a measly $158. One of Kepler's new discoveries is worth nearly a quarter-million dollars, Laughlin figures.

Kepler was launched in 2009 and orbits the sun between Earth and Mars. It needs time to find planets, identifying them by watching them repeatedly move past the star they orbit.

Kepler scientists are strict about calling candidate planets confirmed. Out of the hundreds of candidate planets announced last year, only 15 of Kepler's discoveries had been confirmed  — including six that were announced Wednesday. All of those six are way too hot for life.

More on extrasolar planets:

This report was supplemented by msnbc.com.

Copyright 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Video: New frontiers in planetary science

Interactive: The search for extrasolar planets

Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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