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Astronomers discover another planet made largely out of diamond

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  • Astronomers discover another planet made largely out of diamond

    From: http://www.reuters.com/article/2012/...89A0PU20121011

    LONDON | Thu Oct 11, 2012 10:18am EDT

    Orbiting a star that is visible to the naked eye, astronomers have discovered a planet twice the size of our own made largely out of diamond. The rocky planet, called '55 Cancri e', orbits a sun-like star in the constellation of Cancer and is moving so fast that a year there lasts a mere 18 hours. Discovered by a U.S.-Franco research team, its radius is twice that of Earth's but it is much more dense with a mass eight times greater. It is also incredibly hot, with temperatures on its surface reaching 3,900 degrees Fahrenheit (1,648 Celsius).

    Diamond planets have been spotted before but this is the first time one has been seen orbiting a sun-like star and studied in such detail. "This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth," Madhusudhan said, adding that the discovery of the carbon-rich planet meant distant rocky planets could no longer be assumed to have chemical constituents, interiors, atmospheres, or biologies similar to Earth.
    "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

  • #2
    And De Beers moved immediately to try to gain exclusive mineral rights to the planet

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    • #3
      How did they they figure out what it's made of?

      Comment


      • #4
        Originally posted by llkinak View Post
        How did they they figure out what it's made of?
        They took it to a gemologist...
        Watts Up With That? | The world's most viewed site on global warming and climate change.

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        • #5
          Originally posted by llkinak View Post
          How did they they figure out what it's made of?
          Spectroscopic analyses I imagine. They split up the light coming from the object and are able to identify the elements from the different colors and spacings in the spread out signal.

          But to do that, the light from the planet has to be directly observable. I had thought that up to now, planets outside the Solar System had not been directly observed but their existence inferred by the gravitational effects (wobble) they have on their star or by the distortion they cause in the star's light when they pass in front of it.

          So I'm still a bit puzzled.


          Philip
          "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

          Comment


          • #6
            Might have been deduced from the mass and estimated radius. Carbon being one of the more common elements, there is no reason these sorts of planets should not crop up. Since this topic isn't controversial, wiki should be a safe enough source:

            http://en.wikipedia.org/wiki/Abundan...n_the_Universe

            If the planet is in fact mostly carbon then below a certain depth, diamond should naturally be the most common mineral. Perhaps the next layer above that would be graphite? I'd expect there to still be a small core of heavier elements but I doubt we could get any more detail at this distance.

            Hopefully drakk will drop in and add some details.
            And 'Doc can tell us if any of these planets show up in the Neiman Marcus Christmas catalog.
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            • #7
              I'm sure there is a reason they think/know it's largely diamond, I'd just be interested to know what that is. Deductive logic seems an OK place to start, but I don't know if it would be enough to be conclusive? Maybe it would, I don't know. I'd also be interested to know if their actual paper says they suspect or believe it may be diamond and Reuters is taking a bit of license. Saying what something that is light years away is made of seems like a hard thing to do, but I suppose these folks are pretty bright.

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              • #8
                Extreme temperature and pressure is needed to form diamond. The surface could be graphite and coke as all other violable lighter elements such as hydrogen, nitrogen, oxygen, and surviving hydrocarbons and organic material long ago driven into space.

                The deduction to mostly carbon and thus diamond is based upon the estimated mass of the planet, too light for heavier rocky materials to dominate but just right for a carbon dominated planet. The surface temperature and pressure of the planet's interior just a couple of miles below, are most suited to diamond formation from the white hot carbon.

                Still, mostly speculation based upon a best educated guess.
                “Breaking News,”

                “Something irrelevant in your life just happened and now we are going to blow it all out of proportion for days to keep you distracted from what's really going on.”

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                • #9
                  Originally posted by GCoyote View Post
                  Hopefully drakk will drop in and add some details.

                  And 'Doc can tell us if any of these planets show up in the Neiman Marcus Christmas catalog.


                  If you follow the trail it will lead you to this legitimate scientific paper:
                  A Possible Carbon-rich Interior in Super-Earth 55 Cancri e
                  Nikku Madhusudhan (Yale Univ.), Kanani K. M. Lee (Yale Univ.), Olivier Mousis (CNRS, France)
                  (Submitted on 9 Oct 2012)
                  http://arxiv.org/abs/1210.2720


                  "Terrestrial planets in the solar system, such as the Earth, are oxygen-rich, with silicates and iron being the most common minerals in their interiors. However, the true chemical diversity of rocky planets orbiting other stars is yet unknown. Mass and radius measurements are used to constrain the interior compositions of super-Earths (exoplanets with masses of 1 - 10 Earth masses), and are typically interpreted with planetary interior models that assume Earth-centric oxygen-rich compositions. Using such models, the super-Earth 55 Cancri e (mass of 8 Earth masses, radius of 2 Earth radii) has been suggested to bear an interior composition consisting of Fe, silicates, and an envelope (>= 10% by mass) of super-critical water. We report that the mass and radius of 55 Cancri e can also be explained by a carbon-rich solid interior made of Fe, C, SiC, and/or silicates and without a volatile envelope. While the data allow Fe mass fractions of up to 40%, a wide range of C, SiC and/or silicate mass fractions are possible. A carbon-rich 55 Cancri e is also plausible if its protoplanetary disk bore the same composition as its host star, which has been reported to be carbon-rich. However, more precise estimates of the stellar elemental abundances and observations of the planetary atmosphere are required to further constrain its interior composition. The possibility of a C-rich interior in 55 Cancri e opens a new regime of geochemistry and geophysics in extraterrestrial rocky planets, compared to terrestrial planets in the solar system. "

                  If you read this abstract enough times you will realize that they never say "diamond" at any time, and most of their results are based on computer models using unverified assumptions.

                  Here's the paper:
                  http://arxiv.org/pdf/1210.2720v1.pdf

                  If you do a search on "diamond" it is not in the paper and "Possible" is in the title of the paper which indicates a pretty "weak" scientific result.

                  This is good sensational science publicity, but not good science reporting...
                  Battles are dangerous affairs... Wang Hsi

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                  • #10
                    Originally posted by Pirate-Drakk View Post
                    A carbon-rich 55 Cancri e is also plausible if its protoplanetary disk bore the same composition as its host star, which has been reported to be carbon-rich.
                    At such distances, most conclusions are likely to be inferred rather than observed. Even the existence of the planet itself.

                    That a planet's early mineral composition would be practically identical to that of its host star (which can be directly observed) seems a very reasonable inference to make.

                    I hadn't thought of that as a way to ascertain a planet's composition.


                    Philip
                    "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

                    Comment


                    • #11
                      Originally posted by PhilipLaos View Post
                      At such distances, most conclusions are likely to be inferred rather than observed. Even the existence of the planet itself.

                      That a planet's early mineral composition would be practically identical to that of its host star (which can be directly observed) seems a very reasonable inference to make.

                      I hadn't thought of that as a way to ascertain a planet's composition.


                      Philip
                      Exoplanet articles are particularly good examples of junk science journalism.

                      The existence of exoplanets is inferred from subtle variations in the movement, luminosity and other characteristics of the host stars. The temperature, mass and size of the stars are determined from spectral characteristics. The characteristics and variations of the stars are used to infer the mass, size, density and composition of the inferred exoplanets.

                      The science is sound... The reporting of the science by journalists is atrocious.
                      Watts Up With That? | The world's most viewed site on global warming and climate change.

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                      • #12
                        Originally posted by PhilipLaos View Post
                        At such distances, most conclusions are likely to be inferred rather than observed. Even the existence of the planet itself.
                        There are many assumptions made with these observations. For instance, if you are looking for "wobbles" in the star and infer a planet, you must first assume the star is perfectly symmetric and the wobble is not due to that asymmetry.

                        Most stars are "probably" symmetric but certainly, some are not. How many and what ratios are impossible for our science to determine.

                        Originally posted by PhilipLaos View Post
                        That a planet's early mineral composition would be practically identical to that of its host star (which can be directly observed) seems a very reasonable inference to make.
                        Philip
                        I would rate this as a "weak" assumption.

                        If you take a bucket of rocks and sand of different sizes and shake it, you will not get an even distribution of size particles in the bottom of the bucket. Likewise, protostellar nebulaes are also probably differentiated in composition. That is one reason why comets from the Oort Cloud don't have the same composition as the Earth, and the inner planets.

                        Just because this planet is close to the star doesn't mean if was formed there. In fact, it probably couldn't have formed there due to the excessive gravitational tidal forces.

                        The only way to REALLY understand an exoplanet is to observe it directly. Since we can't even resolve the disk of all but a few stars, observing the planets is impossible.

                        All you get is a flicker of light, a few assumptions, and educated inference to make a case for an exoplanet.
                        Battles are dangerous affairs... Wang Hsi

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                        • #13
                          Originally posted by Pirate-Drakk View Post
                          The only way to REALLY understand an exoplanet is to observe it directly. Since we can't even resolve the disk of all but a few stars, observing the planets is impossible.

                          All you get is a flicker of light, a few assumptions, and educated inference to make a case for an exoplanet.
                          IIRC, the first exo-planets were discovered using observations of consistent, predictable gravitational shifts (wobbles) in the host star. Then, more planets were discovered using predictable variations in luminosity of the host star as its planet moved in front of it.

                          Not sure about the timeline or sequence of those methodologies, but if the two very different techniques are used to observe the same star-planet system and produce the same result, wouldn't that produce a pretty firm conclusion as the the existence and nature of the planet?


                          Philip
                          "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

                          Comment


                          • #14
                            Originally posted by PhilipLaos View Post
                            IIRC, the first exo-planets were discovered using observations of consistent, predictable gravitational shifts (wobbles) in the host star. Then, more planets were discovered using predictable variations in luminosity of the host star as its planet moved in front of it.

                            Not sure about the timeline or sequence of those methodologies, but if the two very different techniques are used to observe the same star-planet system and produce the same result, wouldn't that produce a pretty firm conclusion as the the existence and nature of the planet?


                            Philip
                            The problem is that they went looking for the wobbles under the assumption that the wobbles *were* evidence of exoplanets. This is a form of “confirmation bias.”
                            Last edited by The Doctor; 14 Oct 12, 08:38.
                            Watts Up With That? | The world's most viewed site on global warming and climate change.

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                            • #15
                              Originally posted by The Doctor View Post
                              The problem is that thee went looking for the wobbles under the assumption that the wobbles *were* evidence of exoplanets. This is a form of “confirmation bias.”
                              As I understand it, a hypothesis has to be formed before it can be confirmed or disproved.

                              If the data produced by the gravitational 'wobble' effect are later reproduced using the totally different methodology of luminosity variation, then a pretty solid conclusion can be reached I would imagine.

                              Not that I know that the two methodologies have indeed been applied to the same star-planet system, but I would imagine they have.


                              Philip

                              EDIT: Initially, I wrote "....data.....is...."

                              Bad English teacher, Philip!
                              "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts."— Bertrand Russell

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