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Space Science

13-Billion-Year-Old Alien Worlds Discovered 302

Posted by Soulskill from the i-was-orbiting-when-your-sun-was-in-diapers dept.
astroengine writes "Two exoplanets have been discovered by scientists at the Max-Planck Institute for Astronomy orbiting the star HIP 11952. But according to conventional thinking, these worlds shouldn't exist. You see, HIP 11952 is a 'metal-poor star and planetary formation is hindered around stars with low metallicity (PDF). This isn't the only thing; as metal-poor stars were the first stars to form when the Universe was very young, these two worlds also formed around the same time. They are therefore the most ancient exoplanets discovered to date."
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13-Billion-Year-Old Alien Worlds Discovered More

13-Billion-Year-Old Alien Worlds Discovered

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  • I'm confused (Score:3)

    by viperidaenz ( 2515578 ) on Tuesday March 27, 2012 @07:37PM (#39491705)
    How is this news? Sure its uncommon for these stars to have planets but its not impossible. HIP 13044 is a low Fe/H star (even lower than HIP 11952) with planets.

    • Re:I'm confused (Score:5, Funny)

      by Farmer Tim ( 530755 ) on Tuesday March 27, 2012 @07:45PM (#39491777) Journal

      "Planets form around sun" certainly was news 13 billion years ago, it just took this long to reach Slashdot's front page.

    • it should be impossible as previously thinking was that the only way the elements for planetary formation are created is via prior supernovas. these stars shouldnt have had access to the materials needed to create planets. either there were more -very- early supernovae than thought, or these planets are interstellar captures.

      • well, the life of a star is inversely proportional to its size... the bigger the star, the faster it blows up. it *is* plausible that during the early days of the universe when things were much more densely packed than they are now, bigger stars could have formed early on.

        but I still think they're most likely trapped planets.

      • They're gas giants. They could be 100% hydrogen, thus not needing elements from supernovas.

      • Re:I'm confused (Score:5, Interesting)

        by Michael Woodhams ( 112247 ) on Tuesday March 27, 2012 @08:48PM (#39492305) Journal

        Early supernovae wouldn't help - the star is formed from the same material as the planets would, and the star demonstrably has almost no metals. Early supernovae would just mean that this star didn't exist (in its current chemistry), or that it is even younger than currently estimated, so as to form before the supernovae.

        Interstellar captures are very difficult. Generally speaking, you need three gravitationally interacting bodies to allow a capture, as you need one to carry away some energy. Basically this requires the wanderer planet to turn up just when the star is passing close to another one, and even then to get really lucky. (Most often it is the lowest mass object of the three which gains energy, but we need the planet to lose energy.) Another possibility is you could lose that energy through tidal losses, but this requires the wanderer has very small positive energy initially, and passes very close to the star. Either way, the odds of such a capture are very low.

        In addition, we have the fact that this star has two planets, which makes the odds against capture polynomially* smaller. Finally, if two planets were captured, we'd expect them to have different orbital planes. Given that they were detected by the 'wobble' method, I'd expect this could be measured, and would be mentioned if it had been so. However I can't promise that there aren't gravitational interactions which would bring the orbital planes into alignment over 13Gyr. Captures would also initially have highly elliptical orbits, which again the wobble method should notice, and again I don't know if 13Gyr is long enough to circularize the orbits by tidal effects or planet-planet interactions.

        * This word brought to you by the Committee Against The Misuse Of The Word 'Exponentially'

        • * This word brought to you by the Committee Against The Misuse Of The Word 'Exponentially'

          Why so? If the probability of capture of one planet is p, of two planets is p^2, of three planets is p^3, and in the general case it is p^n, where n is the number of captured planets. Or, in other words, the odds decrease exponentialy.

          • The probability is exponential in n, but for two planets, it is polynomial in p. I'd fixated on the second fact and missed the first. Given the context that we'd just changed n rather than p, I agree that 'exponentially' is more appropriate here.

            I shall submit myself to the Committee for disciplinary action.

        • Re:I'm confused (Score:4, Interesting)

          by tibit ( 1762298 ) on Tuesday March 27, 2012 @10:40PM (#39493037)

          Well said about the capture. It's very interesting to run an N-body gravitational simulation where the initial state is a bunch of things with random masses and velocity vectors. A whole lot of stuff will be ejected as things settle down. Gravitational capture appears to be hard. That's what I learned, to my initial amazement, when I started playing with N-body simulations. I thought the code had bugs. And then I'd input some solar system ephemeris for the planets and a couple other large objects, and voila, it didn't blow up, things were nicely orbiting :)

  • So do we say that these planets "are" orbiting HIP 11952, or that they "were" orbiting HIP 11952?

    • Re:verb tense (Score:5, Insightful)

      by FrankSchwab ( 675585 ) on Tuesday March 27, 2012 @07:54PM (#39491861) Journal

      Well, they're only 375 light-years away, so I'd say that if they had managed to exist for 13 000 000 000 years, they likelihood of them disappearing in the last 375 is pretty low. My bet is on "are".

    • Were, and may still be.

    • Re:verb tense (Score:4, Insightful)

      by Longjmp ( 632577 ) on Tuesday March 27, 2012 @07:58PM (#39491897)
      It doesn't matter.

      Point is that we now know that planets were formed at a very early stage of the universe.
      As for the planets being metal poor, it isn't a surprise really, considering the age of the planets.
      Let's put aside that for astronomers everything beyond helium is a "metal", we are talking about iron (Fe) and heavier elements.
      Suns can only create elements up to iron in a fusion process, everything else is created in a (super) nova, and those were only starting at the beginning of the universe.
      The real surprise here is that planets were formed without (or with few) heavy elements.

    • They are in our reference frame.

    • Re:verb tense (Score:4, Interesting)

      by arth1 ( 260657 ) on Tuesday March 27, 2012 @09:20PM (#39492461) Homepage Journal

      So do we say that these planets "are" orbiting HIP 11952, or that they "were" orbiting HIP 11952?

      Never mind that this star is in our neighborhood, but you make the mistake of thinking of time as a universal (no pun intended) thing. When the light from a distant star hits us, the star does exist, whether the star is billions of light years away or not. It is meaningless to think that the time that the light traveled has passed, because it hasn't. If you were riding the photons from that star, only a moment would have passed for you.
      If we were to go backto the faraway star at the speed of light, we would find it 2*distance older.

      Yes, it's difficult to wrap one's head around, so we make up the comfortable lie of considering distant stars being older proportionally to the distance light and radio waves travel as seen from a fixed point. But that point doesn't exist. Time is always subjective, as long as the speed of light in vacuum is considered constant.

      And if you thought that makes your head hurt, consider that space itself is expanding, so the distance to a far away star is longer than the distance the light has traveled...

  • Captured rogue planets? (Score:3, Insightful)

    by solferino ( 100959 ) <hazchem&gmail,com> on Tuesday March 27, 2012 @07:45PM (#39491781) Homepage

    Possibly they are captured rogue planets [wikipedia.org].

    • That's what I was thinking too. A recent study [stanford.edu] estimates that there may be 100,000 times (!) as many nomad planets in our galaxy as there are stars (est. 100 billion). Considering this huge number and given a time span not far short of the age of the universe, I would think that the likelihood of a long-lived star, such as HIP 11952 (est. 0.83 solar masses), to eventually capture a few of these highly numerous interstellar orphans to be not insignificant.

      • Re: (Score:3)

        by tibit ( 1762298 )

        If all you have is one star and one planet, and you simulate them as point masses (no tidal losses and no slowing down in star's outer atmosphere), capture seems impossible. The planets don't exactly have orbital insertion motors attached. I'd like to see a list of possible mechanisms that would make a capture possible in such a scenario. Remember: to have orbital insertion, you need to dissipate energy. Always.

  • ... discovered Z'Ha'Dum?
  • "Metal poor worlds" - so one of those could be Terminus?

  • Endless Hide & Seek (Score:3)

    by Cazekiel ( 1417893 ) on Tuesday March 27, 2012 @07:55PM (#39491873)

    I think there are simply too many things for us to be 100% on. That, to me, is exciting--it allows us to never run out of things to learn about. If we're wrong, we get to keep trying to find out why.

  • New Universe (Score:5, Insightful)

    by bdabautcb ( 1040566 ) <bodaciouswaggler ... m ['oo.' in gap]> on Tuesday March 27, 2012 @08:03PM (#39491951)
    I am astounded by the amount of rhetoric and vitriol that surrounds astronomical discoveries. Whether or not they are correct, the truth boils down to: we don't have shit for current time observations of anything in the universe. I truly believe that we are on the right path, and models fit observation, but why get so skeptical about everything? By the time we all die, the universe will basically be in the same state. Let's enjoy the limits of our observation, explore and expand them, and then maybe one of our lineage will be able to explore it.
  • These planets are Metal-Poor because the local sentient-life-form mined all the metals and uploaded their consciousness into machines.

  • Y'know, looking at our own gas giants, it seems you don't need a whole lot of heavier elements to create a non-fusioning sphere around a star. Granted, Jupiter, Saturn, et al seem to have a lot of goodies further down the periodic table. But, I'd guess that planetary formation will work with whatever is in the buffet, even if it's just H and He with a salting of impurities.

  • Don't worry, it'll leave once Alderaan gives up...

  • Thought I just found a fellow creature, then I realized it was not saying "13-Billion-Year-Old Alien Discovered". Sigh.

  • Av shown this page to a non-geeky friend... (Score:3, Interesting)

    by Nrrqshrr ( 1879148 ) on Tuesday March 27, 2012 @08:50PM (#39492311)
    ... And she was delighted. It's really natural for us to think that the universe is that old, and that our vision of it is like lag in an online game. But there is something utterly satisfying when you show this to someone who isn't that much into cosmic timetables and when you watch their reactions as they try to imagine the scale, and their faces when they realise just how meaningless this planet is.
    News like this should really become mainstream. This kind of humbling, nihilistic conceptualisation of our lives and surroundings could, ironically, save mankind from whatever foolish suicide we'r preparing to ourselves.
  • The system is metal poor, so it can't be Cybertron. I would guess Gallifrey if one of them had been terrestrial.
  • these planets shouldn't exist according to our current understanding, or challenged what we think we know.

  • If one has a glowing green band I propose we call it Oa.

  • So we found planets older than dirt. (Score:5, Funny)

    by netsavior ( 627338 ) on Tuesday March 27, 2012 @10:13PM (#39492865)
    another idiom busted

  • This may be a very bad sign- Great Filter? (Score:4, Interesting)

    by JoshuaZ ( 1134087 ) on Tuesday March 27, 2012 @10:14PM (#39492875) Homepage
    While this discovery is very cool, it may be a very bad sign. One of the most plausible explanations for the Fermi paradox is that intelligent life almost always wipes itself out before it is able to engage in largescale space travel (as so-called Great Filter http://en.wikipedia.org/wiki/Great_filter [wikipedia.org]. One of the other more satisfying explanations is that the sun is one of the first stars to have enough metal to plausibly form planets. That now seems to be less likely. There are other explanations, such as the low metal systems not having enough carbon for life to form and prosper, or that complex life is very rare. However, this discovery potentially removes one of the more plausible possible explanations, and thus makes the possibility of a Great Filter in our future to seem more likely. This is disturbing.

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