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NASA Scientists Simulate Black Hole Collision 63

Krishna Dagli writes to tell us Yahoo! News is reporting that NASA scientists have managed to simulate the merger of two massive orbiting black holes. Using technology from Silicon Graphics, Inc. built from 20 SGI Altix systems the team was able to show how the resulting gravitational waves would interact with surrounding space.
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NASA Scientists Simulate Black Hole Collision

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  • by uioreanu ( 554486 ) * <prophp&gmail,com> on Wednesday July 26, 2006 @04:16AM (#15782339) Homepage
    By linking four, 512-processor Altix systems .... NASA enabled the scientists to access all of the processors' memory at once.
    • They actually have several layers of memory (registers, L1, L2...), it's just not called that.

      I don't think that's what they meant though.
      • "I don't think that's what they meant though."
        Really??? If you look down the bottom of TFA it says "Source: SGI" Given that TFA talks more about the SGI systems than than the actual experiment, and SGI wrote TFA, they should know better. But then again, it is just marketing....
        • by prefect42 ( 141309 ) on Wednesday July 26, 2006 @06:57AM (#15782710)
          I think you need to relax your terminology a little. On an Altix box you have what used to be called C-Bricks. Basically a unit that contains processors and RAM. Those all link together over NUMAFlex (with appropriate routers) to form your large shared memory machine. But the RAM is still localised (as it's a NUMA architecture). So 'main memory' should be considered as 'owned' by a processor (or processors). If you'd made an OpenMOSIX cluster to match you'd refer to it as a machine's memory, but since all these C-Bricks form a single machine whole, you can't do that.
    • by Anonymous Coward
      What they mean is that they were able to join the address spaces of the different machines to form a single, unified one. Without any extra software, a processor can thus execute load and stores to the memory of a different machine simply by using an address that is mapped to the memory of another SGI Altix - the machine does all the rest.

      In other words, you're able to use shared-memory forms of multi-processor programming, such as threads, instead of message-passing, as is used e.g. by clusters (think pthr
  • imagine (Score:2, Funny)

    by Criliric ( 879949 )
    imagine a beowolf.... nevermind :)
  • by MindCheese ( 592005 ) on Wednesday July 26, 2006 @04:34AM (#15782393) Homepage
    Man, that would suck.
  • Summary (Score:2, Interesting)

    by miikrr ( 799637 )
    The first video is looks pointless. It just shows two black holes circling around each other doing nothing, and then the clip just ends. Einstein's clip shows two black holes merging into one big-ass black hole, which shows a much more interesting theory than "nothing really happens when two black holes meet, but here's a video anyway!"
    • Well, that's the way these things act out in the real world - they orbit each other for several millions years, gradually losing orbital energy, then they merge within minutes (at least to an observer, for someone on the surface of each black hole it's probably going to seem like an eternity).

  • How? (Score:4, Insightful)

    by squoozer ( 730327 ) on Wednesday July 26, 2006 @04:49AM (#15782433)

    I wasn't aware that we understood how one black hole worked so how can this team perform a simulation of two coming together and hope to get anything useful out? I admit there is an outside chance they will stumble on the correct result but can they prove it's correct?

    • Without those kinds of spending no kid would ever have heard of a computer, since their wouldn't be any, since noone got the funds to develop some.
      • The problem with your argument is that it can be used to justify any research no matter how hair brained. It could be used to justify research into perpetual motion machines or ID. I freely admit some money needs to be spent on blue sky research but even that should be justifiable. If the results that we get out of this experiment are nothing more than one researchers opinion then they are worth no more than a (very expensive) work of fiction. It's great that we are probing these things but there comes a po

        • "The problem with your argument is that it can be used to justify any research no matter how hair brained. It could be used to justify research into perpetual motion machines or ID."

          Not really thats why research proposals get generally peer reviewed - which isn't always an ideal process, but it does generally get the perpetual motion machines, I've discovered the ether, and CPT violating transportation devices type projects thrown out.
    • Re:How? (Score:3, Informative)

      by amRadioHed ( 463061 )
      The thing we don't understand about black holes is the singularity itself. The observable behavior of the black hole is mostly understood and I think that is what is being simulated. The stuff that is truly mysterious is hidden away within the event horizon.
      • The observable behaviour of black holes? Everyone seems to have forgotten that black holes are just limits of a purely hypothetical mathematical model - and have never been observed, ever.

        The supposed effects which have been observed as "indirect evidence" of black holes is a fantastic leap of faith with no basis in observable or testable reality (nor even in the above-mentioned mathematical models, i'll wager).
        • Re:How? (Score:1, Informative)

          by Anonymous Coward
          I'm a physics student and have to complain a bit.

          The "purely hypothetical mathematical model" is known as General Relativity - a theory which has sustained every test physicist could conceive so far.
          Blacks holes itself not only were found to be the fate of any superdense object in this theory but are widely accepted by almost any physicist as real.

          Wikipedia gets it right:

          The existence of black holes in the universe is well supported by astronomical observation, parti

    • while (1)
      expected_phenomena = simulate(current_theory);
      observed_phenomena = look_for_similar(expected_phenomena);
      current_theory.refine(expected_phenomena, observed_phenomena);
    • Well we understand general relativity which we can model on a computer. We also have a pretty good grasp of particle physics which we can also model with a much bigger computer. Now from my understanding these two theories create different results in things like blackhole simulations. It would be interesting to simulate the two and eventually someday we may observe this actually happening and find out which simulation was more correct.
    • Re:How? (Score:1, Insightful)

      by Anonymous Coward
      > I wasn't aware that we understood how one black hole worked so how can this team perform a simulation of two coming together and hope to get anything useful out?

      We have a pretty good idea. The equations being used to produce these simulations fit with observed evidence. About which, more:

      > I admit there is an outside chance they will stumble on the correct result but can they prove it's correct?

      See, this is the tricky part. We have a set of equations which look good mathematically. The equations fit
    • This calls for empirical methods! Fire up the cyclotron, it's time we started smashing black holes into each other!

    • We do not understand the inside of black holes, and we have a limited understanding of the surface of black holes. What we do have an excellent understanding of is the space between black holes, and the motion of the black holes through space. Relativity gives us the (very complicated) equations for everything outside of the black hole.

      And an interesting thing about Relativity is that the interior of a black hole cannot have any causual effect on anything outside the black hole. So we don't know what happen
  • Now lets do it for real.
  • The date on the Nasa page is 18 April.

  • That's good to know, in case one is ever caught in the middle of two colliding black holes and you need to figure a way out of that sticky situation....

  • Some more info. (Score:5, Informative)

    by Stoutlimb ( 143245 ) on Wednesday July 26, 2006 @08:18AM (#15782921)
    I actually went to a seminar years back by one of the individuals working on this. The equation alone filled pages, and was something he had to derive by hand. He showed us a cgi video of the results. The 2 black holes approached, snapped together, and the resulting larger black hole temporarily oscillated. The strange part was partway through the oscillation, the black hole just popped out of existence, and then reappeard several seconds later.

    In the question and answer period, a student asked why this gap in the calculations. The professor explained there was no gap in the calculations, but rather, the result of the calculations was non-euclidean in nature, so it was physically impossible to display it in a 3d model. At about that time, half of the undergrad audience whispered a Keanu Reeves style "whoah..."

    Don't ask me any of the details, this was years ago in a course on stellar astrophysics that I have mostly forgot. This is just something anecdotal. Astrophysicists have been working on this black hole merger thing for a very long time. The computer labs at the time had P133's running. I'd love to see what they're doing now, but that site wasn't very big on actual information.
    • I went through the videos on that site I missed. I could swear I saw the EXACT SAME videos at the 1993 conference. Especially the one that showed the gravity waves of the two merging black holes. I swear I even see the resulting black hole wink out for a frame or two. They really don't show the actual merger in very much detail at all, I think this is on purpose. I think that's why they havn't posted anything that clearly shows the merger, because I very much doubt an observer at the merger of 2 black
      • I was at that conference I think (U of C, CUPC?) and I saw the same videos. I also believe they were the same thing. Maybe they've been recreated with more precision or something? I hope so.
        • Cool, what U were you from? I was from U of A.

          Call me a cynic, but my guess is the prof took out his old promo material, and is asking for more funding by showing what he's done so far. Either that, or they have recreated the same computing, but with more resolution or something.
    • My gut hunch is that's a good approximation of the big-bang, two half universe sized black-holes kissing!
  • This is new news?

    This article and movie was featured in New Scientist on 4.18.06.

    Black holes collide in the best simulation yet

    18:29 18 April 2006 news service

    Enlarge image
    Black holes distort space-time (yellow lines) and emit gravitational waves as they spiral towards each other (Image: Henze/NASA)

    Enlarge image
    Simulations of the ripples in space-time produced when two black holes merge could help astronomers interpret future gravitational wave observations (Image: Henze/NASA)

    The ripples in
  • The original paper can be found here []. From what I understand of the original paper, they only did a non-rotating black holes. This paper is a significant step forward in numerical relativity because they were able to actually get information out about the gravitational waves that carry the energy away from the two black holes and allow for the inspiral to happen.

    As mentioned in the paper, a lot of previous work has been done on this problem. Up to this point, one of the methods used was a ci []
  • so I have a few problems with this type of article.

    first off, the result is an obvious PR piece for SGI. Such a slant taints the reason for the piece - making it impossible to really judge the significance of the computation. The contactacts ARE the SGI PR folks.

    next, the article frames this an achievement in simulation that was "made possible" by the computer. This framing shows the lack of understanding about simulation by the author. In all computer simulation, there is a tradeoff between realism/acc
  • Wow, they must've spent nearly $2000 on all those SGIs on ebay.
  • No expert here, but I do recall reading some commentary about string theory predicting multiple universes. The potential importance of this research is that gravity waves may be the only way to communicate between multiple universes!!!! (unless T-mobile installs some new cell towers in the other universes). Understanding and detecting them could lead to some future communication revolution.
  • This is nice and all, i mean im glad to see great minds working together but this just didnt interest me that much because of how little we know about black holes.

    anyways thats just my opinion

Make it myself? But I'm a physical organic chemist!