2 Earth-size Planets Spotted Around Distant Star

By: Malcolm Ritter, Associated Press
By: Malcolm Ritter, Associated Press

New York, NY (AP) - Scientists have found two Earth-sized planets orbiting a star outside the solar system, an encouraging sign for prospects of finding life elsewhere.

The discovery shows that such planets exist and that they can be detected by the Kepler spacecraft, said Francois Fressin of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. They're the smallest planets found so far that orbit a star resembling our sun.

Scientists are seeking Earth-sized planets as potential homes for extraterrestrial life, said Fressin, who reports the new findings in a paper published online Tuesday by the journal Nature. One planet's diameter is only 3 percent larger than Earth's, while the other's diameter is about nine-tenths that of Earth. They appear to be rocky, like our planet.

But they are too hot to contain life as we know it, with calculated temperatures of about 1,400 degrees and 800 degrees Fahrenheit, he said.

Any life found on another plant may not be intelligent; it could be bacteria or mold or some completely unknown form.

Since it was launched in 2009, NASA's planet-hunting Kepler telescope has found evidence of dozens of possible Earth-sized planets. But Fressin's report is the first to provide confirmation, said Alan Boss of the Carnegie Institution for Science in Washington. He's a member of the Kepler science team but not an author of the paper.

The researchers ruled out a possible alternative explanation for the signals that initially indicated the planets were orbiting the star Kepler-20. The star is 950 light-years from Earth in the direction of the constellation Lyra.

The planets, called Kepler-20e and Kepler-20f, are part of a five-planet system around the star, and their location challenges current understanding of how planets form, scientists said. In our own solar system, the small rocky planets are closest to the sun, while gaseous giants are on the periphery. But the five-planet system has no such dividing line; big and small planets alternate as one moves away from the star.

That's "crazy," and unexplained by current understanding of how planets form around stars, said study co-author and Harvard scientist David Charbonneau.

Earlier this month, scientists said they'd found a planet around another distant star with a life-friendly surface temperature of about 72 degrees. But it was too big to suggest life on its surface. At 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, scientists said.

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Online:

Nature: http://www.nature.com/nature


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  • by One Shot Location: One Kill on Dec 21, 2011 at 01:18 PM
    Let's send Obumma to check it out. He can become ruler of planet dumb***!
  • by Gerry Location: Tallahassee on Dec 21, 2011 at 10:07 AM
    The patch of sky Kepler stares at is best seen in the summer. The article mention the constellation Lyra, the lyre or harp. 2 nearby constellations to Lyra are Cygnus, the swan, and Aquila, the eagle. The brightest stars in Lyra, Aquila, and Cygnus are respectively Vega, Altair, and Deneb. Vega is the 5th brightest star in the sky; Altair is 12th; Deneb is 19th. The 3 stars are the corners of the the Summer Triangle. Here is the Astronomy Picture of the Day from 6/25/10:http://apod.nasa.gov/apod/ap100625.html Mouse over to see captions. Toward the lower right you will see Antares, the brightest star in the constellation Scorpius, the scorpion.
  • by tally Location: tally on Dec 21, 2011 at 06:33 AM
    Maybe its Pluto?????
  • by Anyone? on Dec 21, 2011 at 06:05 AM
    What about Elenin, we have a huge asteroid that has entered our system and has been at best coincidental in the direct relation to the earthquakes on this planet and the shift in our magnetic poles. I've heard some scientist say the earth has shifted already and we may be in for even more earth changing events. Whats the latest on that Gerry?
    • reply
      by Gerry on Dec 21, 2011 at 09:33 AM in reply to Anyone?
      Elenin is a comet. Your post is the first I'd heard of it. It began to disintegrate in August of 2011 and reached its closest approach to Earth on October 16, 2011, at a distance of over 21 million miles. By comparison, the Moon is 240 thousand miles from Earth. Before breakup, the diameter of its nucleus was less than 5 miles. It wouldn't seem to have the mass to do much of anything to Earth.
  • by Gerry Location: Tallahassee on Dec 20, 2011 at 07:13 PM
    The Kepler spacecraft is a telescope, orbiting our Sun, and staring at the same piece of our galaxy year after year, now for almost 3 years. Kepler looks at 100,000 or more stars trying to detect dimming in the light from a particular star as a planet orbiting the star crosses in front of it. A planet crossing in front of the star will cause light to dim at regular intervals. Kepler needs to detect 3 regular, periodic dimmings in order to confirm that it has detected a planet, or rather, a planet candidate. The candidate must be confirmed as a planet by ground-based follow-up observations. Kepler has found 2,326 candidate planets as of this month.
  • by Al Sharp... on Dec 20, 2011 at 06:39 PM
    You have a lot of spare time gerry!LOL.What is the diameter of your cranium?LOL
  • by Jake on Dec 20, 2011 at 06:23 PM
    God will never allow us to transport mankind's sickness to another civilization, no matter how many planets we find.
  • by Anonymous on Dec 20, 2011 at 06:08 PM
    http://www.planetary.org/blog/article/00003309
  • by Gerry Location: Tallahassee on Dec 20, 2011 at 03:37 PM
    The diameter of Venus is 95% the diameter of Earth. Kepler-20e has a diameter 90% of Earth's and Kepler-20f has a diameter 103% of Earth's. As somebody pointed out, these discoveries double the number of known Earth-sized planets from 2 to 4. Kepler-20e is about 5 million miles from its star whereas Kepler-20f is 10 million miles from that same star. The mean distance of Mercury from our Sun is 36 million miles. This star, Kepler-20 is now known to have 5 planets. Oddly enough they alternate: gas giant, rocky, gas giant, rocky, gas giant as you move farther from the star. There is a gas giant BETWEEN the new Kepler-20e and Kepler-20f. Also, all 5 planets orbit closer to their star than Mercury is to our Sun.
    • reply
      by Sara on Dec 20, 2011 at 08:56 PM in reply to Gerry
      Tell us some more, Gerry. I love this stuff. What an amazing solar system for Kepler-20. Why are the planets so close to their star - well, as compared to us? How wonderfully strange that they alternate. Thank you for posting.
      • reply
        by Gerry on Dec 20, 2011 at 11:10 PM in reply to Sara
        Thanks for the compliment. I don't know the answer to your question. In the future please ask easier, less profound questions.
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