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  • Scientists discover a nearly Earth-sized planet

    Scientists discover a nearly Earth-sized planet

    By JENNIFER QUINN, Associated Press Writer Jennifer Quinn, Associated Press Writer – 1 hr 36 mins ago
    HATFIELD, England – In the search for Earth-like planets, astronomers zeroed in Tuesday on two places that look awfully familiar to home. One is close to the right size. The other is in the right place. European researchers said they not only found the smallest exoplanet ever, called Gliese 581 e, but realized that a neighboring planet discovered earlier, Gliese 581 d, was in the prime habitable zone for potential life.

    "The Holy Grail of current exoplanet research is the detection of a rocky, Earth-like planet in the 'habitable zone,'" said Michel Mayor, an astrophysicist at Geneva University in Switzerland.

    An American expert called the discovery of the tiny planet "extraordinary."

    Gliese 581 e is only 1.9 times the size of Earth — while previous planets found outside our solar system are closer to the size of massive Jupiter, which NASA says could swallow more than 1,000 Earths.

    Gliese 581 e sits close to the nearest star, making it too hot to support life. Still, Mayor said its discovery in a solar system 20 1/2 light years away from Earth is a "good example that we are progressing in the detection of Earth-like planets."

    Scientists also discovered that the orbit of planet Gliese 581 d, which was found in 2007, was located within the "habitable zone" — a region around a sun-like star that would allow water to be liquid on the planet's surface, Mayor said.

    He spoke at a news conference Tuesday at the University of Hertfordshire during the European Week of Astronomy and Space Science.

    Gliese 581 d is probably too large to be made only of rocky material, fellow astronomer and team member Stephane Udry said, adding it was possible the planet had a "large and deep" ocean.

    "It is the first serious 'water-world' candidate," Udry said.

    Mayor's main planet-hunting competitor, Geoff Marcy of the University of California, Berkeley, praised the find of Gliese 581 e as "the most exciting discovery" so far of exoplanets — planets outside our solar system.

    "This discovery is absolutely extraordinary," Marcy told The Associated Press by e-mail, calling the discoveries a significant step in the search for Earth-like planets.

    While Gliese 581 e is too hot for life "it shows that nature makes such small planets, probably in large numbers," Marcy commented. "Surely the galaxy contains tens of billions of planets like the small, Earth-mass one announced here."

    Nearly 350 planets have been found outside our solar system, but so far nearly every one of them was found to be extremely unlikely to harbor life.

    Most were too close or too far from their sun, making them too hot or too cold for life. Others were too big and likely to be uninhabitable gas giants like Jupiter. Those that are too small are highly difficult to detect in the first place.

    Both Gliese 581 d and Gliese 581 e are located in constellation Libra and orbit around Gliese 581.

    Like other planets circling that star — scientists have discovered four so far — Gliese 581 e was found using the European Southern Observatory's telescope in La Silla, Chile.

    The telescope has a special instrument which splits light to find wobbles in different wavelengths. Those wobbles can reveal the existence of other worlds.

    "It is great work and shows the potential of this detection method," said Lisa Kaltenegger, an astronomer at the Harvard-Smithsonian Center for Astrophysics.

    ___

    Associated Press Science Writer Seth Borenstein contributed to this report from Washington.

    Source:

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  • #2
    Re: Scientists discover a nearly Earth-sized planet

    Good find! I think the AP article neglected a tiny thing. It seems that the planet would be uninhabitable due to the large amount of radiation it would receive. This makes sense since they mention here that it's a red start, meaning it's a red giant. So, it's expanded and is dying and it the process it's radiation output is increased (if memory serves). Earth may or may not (more likely not) be swallowed when our own sun goes red giant toward the end of its life. If it isn't, live would be impossible anyway because it would be hot, but also because of the absurd radiation. This planet is further from its sun than Earth would be at that stage, but it seems the radiation is still too great.

    I'll update the thread if Phil Plait writes about this discovery (I imagine he will). I'm adding the NYT article below though because it doesn't make it sound as much like life is actually possible on this planet.
    That shouldn't lead to underestimation of the importance of discovery though because according to my limited understanding it is very difficult to find planets, but when they have found them, they usually find the gas giants like Jupiter and are unable to detect smaller rocky planets. So, this demonstrates that we're getting better at this task.

    Originally posted by NYT

    European astronomers said Tuesday that they had discovered the smallest planet yet found orbiting another star. The planet could be as little as only 1.9 times as massive as the Earth and belongs to a dim red star known as Gliese 581, which lies about 20 light-years from Earth in the constellation Libra.

    The star was already know to harbor at least three more massive planets. The new planet, known as Gliese 581e, is probably rocky like the Earth, but it lies in such a close orbit — only three million miles from its star — that it is surely blasted with too much radiation and heat to be livable.

    Michel Mayor, of Geneva Observatory, and his colleagues announced their results at a conference at the University of Hertfordshire in Britain and in a paper submitted to the journal Astronomy and Astrophysics.

    Astronomers said the discovery was more encouragement that the galaxy was full of small-mass planets and that with more time and improved instruments like the Kepler satellite, recently launched by NASA, they would eventually find Earth-like planets in orbits suitable for life around other stars.

    “Finding Earth-like planets with lukewarm temperatures is the next great goal,” Geoff Marcy, of the University of California, Berkeley, a planet-hunting rival of Dr. Mayor’s, said in an e-mail message.

    “This is the most exciting discovery in exoplanets so far,” Dr. Marcy said.

    Dr. Mayor’s group also discovered the first exoplanet, a gas giant 160 times the mass of the Earth, in 1995, using a technique known popularly as the “wiggle” method that detects planets by a slight gravitational tug they give their stars. The method is most sensitive to massive planets in close orbits. In a statement, Dr. Mayor noted that the new planet is only one-eightieth of the mass of the first one, saying, “This is tremendous progress in 14 years.”

    The discovery also cements the Gliese system as one of the most promising exoplanet systems. Two years ago, the third planet from that star was hailed as a ”Goldilocks” planet, where liquid water and thus life might be possible, until calculations showed that the greenhouse effect would broil it.

    But the new data also shifted the orbit of the star’s outermost planet inward so that it now appears to revolve in the so-called habitable zone where liquid water is possible, according to Stéphane Udry of Geneva University, one of the team members.

    That planet, 581d, is about seven times as massive as the Earth, Dr. Udry explained, which is too big to be just rock. It probably formed as a combination of ice and rock farther out in the Gliese system and then migrated inward, according to various planetary formation models, and melted. He called it the first serious “water world candidate.”

    Sara Seager, a planet theorist at the Massachusetts Institute of Technology, said in an e-mail message that the Gliese planetary system “is like the gift that keeps on giving.”
    Click for NY Times article
    [COLOR=#4b0082][B][SIZE=4][FONT=trebuchet ms]“If you think you can, or you can’t, you’re right.”
    -Henry Ford[/FONT][/SIZE][/B][/COLOR]

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    • #3
      Re: Scientists discover a nearly Earth-sized planet

      Only 20.5 light years eh? Well let's get those space shuttles into gear....

      ONE light year is 9,460,730,472,580.8 km or roughly 5,912,956,545,362.5 miles

      The size of the planet doesn't really matter... the composition, atmoshpere as well as the gravity on the surface would determine whether or not its habitable for us Earthlings.

      Shouldn't we try to find intelligent life on THIS planet first? If only we were intelligent enough to not make tools to kill each other and/or destroy our planet. I think we have a long way to go to call ourselves intelligent.
      "Nobody can give you freedom. Nobody can give you equality or justice or anything. If you're a man, you take it." ~Malcolm X

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      • #4
        Re: Scientists discover a nearly Earth-sized planet

        Originally posted by KanadaHye View Post
        Only 20.5 light years eh? Well let's get those space shuttles into gear....

        ONE light year is 9,460,730,472,580.8 km or roughly 5,912,956,545,362.5 miles

        The size of the planet doesn't really matter... the composition, atmoshpere as well as the gravity on the surface would determine whether or not its habitable for us Earthlings.

        Shouldn't we try to find intelligent life on THIS planet first? If only we were intelligent enough to not make tools to kill each other and/or destroy our planet. I think we have a long way to go to call ourselves intelligent.
        I think the size of the planet does kind of matter through its relationship to the things you mentioned. For one, larger planets don't tend to be rocky, so that's that's tied to composition. Second, the size is related to the gravity (when talking about rocky planets anyway). But more importantly, the size is also important for magnetism. For instance, Mars lost its protective atmosphere and therefore its water because it's too small. It was not large enough to retain a molten core which is what generates the magnetism.

        We don't need to send a shuttle/probe/etc there, but if we are close enough or can get close enough to get accurate measurements about it (we can do this for stars, but the planet may be too small or not be measurable by same method), it could tell us a little about what might happen to the Earth as the Sun starts to go red giant on us. Given the vastness of space, 20.5 light years is actually pretty close.
        [COLOR=#4b0082][B][SIZE=4][FONT=trebuchet ms]“If you think you can, or you can’t, you’re right.”
        -Henry Ford[/FONT][/SIZE][/B][/COLOR]

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        • #5
          Re: Scientists discover a nearly Earth-sized planet

          You mean liquid metal core. Some people assume that twice the size means twice the gravity which isn't the case... since the gravity also depends on the density of the planet. So the planet doesn't have to be exactly the same size as Earth. They make it sound like they are searching for Earth's twin.
          "Nobody can give you freedom. Nobody can give you equality or justice or anything. If you're a man, you take it." ~Malcolm X

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          • #6
            Re: Scientists discover a nearly Earth-sized planet

            Originally posted by KanadaHye View Post
            You mean liquid metal core. Some people assume that twice the size means twice the gravity which isn't the case... since the gravity also depends on the density of the planet. So the planet doesn't have to be exactly the same size as Earth. They make it sound like they are searching for Earth's twin.
            Yes, density is important. For example, Mercury is much smaller than Mars, but is is more dense and therefore has greater surface gravity. But size is still related (i.e., knowing the size still accounts for a significant portion of the variability in gravity). They're not looking for a twin exactly, but one similar in the ways they've decided make a planet habitable. But I agree, the news articles do make it sound like the similarity in size is more important than it seems and needs to be closer than it actually does. The one they're talking about is 2x the size. That difference ended up being HUGE for Mars which is 40% the size of Earth.
            [COLOR=#4b0082][B][SIZE=4][FONT=trebuchet ms]“If you think you can, or you can’t, you’re right.”
            -Henry Ford[/FONT][/SIZE][/B][/COLOR]

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            • #7
              Re: Scientists discover a nearly Earth-sized planet

              200 years from now 20.5 light years will probably be 2 weeks away due to better and faster inventions.

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              • #8
                Re: Scientists discover a nearly Earth-sized planet

                Originally posted by Sero View Post
                200 years from now 20.5 light years will probably be 2 weeks away due to better and faster inventions.
                That's what people thought in the 60's when sci-fi became popular. We're still waiting to come out of the Flintstone's era.... or get back on the moon. I still Dream of Jeanie.
                "Nobody can give you freedom. Nobody can give you equality or justice or anything. If you're a man, you take it." ~Malcolm X

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                • #9
                  Re: Scientists discover a nearly Earth-sized planet

                  My guess because we already discovered how technology works. Now we're up and running. I give it 300-500 years max.

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                  • #10
                    Re: Scientists discover a nearly Earth-sized planet

                    Originally posted by Sero View Post
                    My guess because we already discovered how technology works. Now we're up and running. I give it 300-500 years max.
                    Technology is actually held back and trickled down to us peons at the bottom. Large corporations buy up any patents from inventors and hold on to them until they are done exploiting the current market for profit.
                    "Nobody can give you freedom. Nobody can give you equality or justice or anything. If you're a man, you take it." ~Malcolm X

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