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Space Science

New Interactive Black Hole Simulation Published 107

Posted by timothy
from the watch-for-these-danger-signs dept.
quaith writes "The New Scientist reports on a simulation just published in the American Journal of Physics that shows how the sky would appear in the vicinity of a black hole — if an observer could actually get near one. Using real positions of around 118,000 stars, the simulation shows how the bending of light, the frequency shift, and the magnification caused by gravitational lensing and aberration in the vicinity of the black hole affect the sky's appearance. The simulation is interactive and allows the user to explore the stellar sky around the black hole. The simulation offers a couple of modes: 'quasi static' or 'freely falling' and the sample videos are quite spectacular. The New Scientist has a writeup, with an embedded video . The original article citation is here (abstract only). The simulation, which runs on Linux or Windows, as well as sample videos, can be downloaded from the University of Stuttgart website."
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New Interactive Black Hole Simulation Published

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  • yes, but (Score:5, Funny)

    by Anonymous Coward on Saturday February 13, 2010 @10:14PM (#31132058)

    does it...

    which runs on Linux

    Oh. sorry.

    • Yes, but... (Score:3, Interesting)

      by 2.7182 (819680)
      is there really anyway to check the correctness of this?
      • Re:Yes, but... (Score:4, Interesting)

        by shaitand (626655) on Saturday February 13, 2010 @10:55PM (#31132254) Journal

        The actual correctness? no. and there probably never will be.

        I'm sure physics geeks will be heartily debating the THEORETICAL correctness any minute now. After all, what else would they be doing on a saturday night

        • by blindseer (891256) <blindseer@@@earthlink...net> on Saturday February 13, 2010 @11:45PM (#31132462)

          After all, what else would they be doing on a saturday night

          Posting on Slashdot?

        • I'm sure physics geeks will be heartily debating the THEORETICAL correctness any minute now. After all, what else would they be doing on a Saturday night.

          Stargate Marathon!!! YEaaaaah....

        • Re: (Score:3, Informative)

          by iluvcapra (782887)
          IANAP, but I seem to recall that images that depict gravitational lenses tend to show stars near the lens deforming into arcs; in this movie stars in the background remain points, even though at least some of them would deform into arcs as they passed behind the object.
          • The images of gravitational lensing typically show galaxies deforming into arcs, I'm not sure about stars. Stars are effectively point sources in even the best telescopes, so that may make a difference.

          • by TheLink (130905)
            How about light from stars to the side (and other directions) of the object and not just behind?
          • by Chris Burke (6130)

            IANAP, but I seem to recall that images that depict gravitational lenses tend to show stars near the lens deforming into arcs; in this movie stars in the background remain points, even though at least some of them would deform into arcs as they passed behind the object.

            Not necessarily, see Einstein's Cross [wikipedia.org].

            Also, watching the video on the New Scientist, stars definitely do get distorted and stretched around the black hole, just not into the large arcs you'll often see in pictures of gravitational lensing tak

        • Re:Yes, but... (Score:5, Informative)

          by HeronBlademaster (1079477) <heron@xnapid.com> on Sunday February 14, 2010 @03:56AM (#31133280) Homepage

          After all, what else would they be doing on a saturday night

          How about playing Star Trek Online on one monitor while watching Farscape (via Netflix) on the other monitor?

        • by Tim C (15259)

          Well, I was drinking and watching Quarantine on Saturday night - today's Sunday in my time zone :)

        • by Zumbs (1241138)

          I'm sure physics geeks will be heartily debating the THEORETICAL correctness any minute now. After all, what else would they be doing on a saturday night

          Obligatory xkcd [xkcd.com].

        • by rhook (943951)

          After all, what else would they be doing on a saturday night

          Sitting in their mothers basement?

      • Well, there's always the LHC... ;)
      • Yes. Run it on Linux <rimshot>
    • Re: (Score:1, Funny)

      by Anonymous Coward
      I was so afraid to click, worried whether it was Goatse. But my fears were naught. However, what is Rick Astley doing orbiting around a black hole?
    • by Tablizer (95088)

      Very good, now show us what hot grits look like being sucked into a blackhole.

    • System requirements

      * At least 300MB GPU memory.
      * The Linux version needs the free Qt SDK which can be found here.

      The application was tested with the graphics boards: NVidia GeForce 8600 GT, ATI Radeon HD 3800.
      Distortion of the stellar sky by a Schwarzschild black hole, [uni-stuttgart.de]
      Thomas Müller, Daniel Weiskopf

      it has some pretty stiff hardware requirements!

  • why? (Score:4, Funny)

    by Anonymous Coward on Saturday February 13, 2010 @10:21PM (#31132088)

    Why are they releasing that code? People are just going to try to find something wrong with it!

  • The simulation, which runs on Linux or Windows, as well as sample videos can be downloaded from the University of Stuttgart website.

    From TFwebsite:

    The following data files have to be stored in the 'data' directory of the application:

    # Distortion array for the region above the horizon: array_outside.bin (binary data file, 128MB).
    # Distortion array for the region below the horizon: array_inside.bin (binary data file, 128MB).
    # Integral psi_V as a function of temperature: psitemp.bin (binary data file, 2

    • Now that would be interesting; partly for the science, and partly because it would rile up the paranoid nuts.

    • ...wow. Is it really not compressible, or did they not even try?

      • Apparently, they didn't even try. The fastest compressor I know, lzop -1, shaves off almost 40 megs. The best one I know that we could reasonably expect people to have is lzma (included by default on Debian systems), and that cuts the file in half -- more than -- from 262 megs to 111 megs.

        I hope the university has gzip compression enabled, but either way, whoever did this is wasting more than double bandwidth of their university in a slashdotting because they couldn't be bothered to compress files. WTF?

  • The link is here, but the file is 262MB.
    http://www.vis.uni-stuttgart.de/~muelleta/IntBH/DataDssBH.tar [uni-stuttgart.de]

    Can someone set up a torrent?

  • Warning! (Score:4, Funny)

    by fuzzyfuzzyfungus (1223518) on Saturday February 13, 2010 @10:34PM (#31132156) Journal
    Whatever you do, for the love of all things good, Do Not invoke the simulation program with the -goatse switch....
    • by Tablizer (95088)

      Do Not invoke the simulation program with the -goatse switch

      Actually, they are very similar such that one may not tell the difference.
         

  • Not new (Score:2, Informative)

    by Anonymous Coward

    Alain Riazuelo at the Paris Institute of Astrophysics similar stuff years ago and even published a special DVD in a French magazine. It is sad they do not credit him at all, not very ethical.

    http://www2.iap.fr/users/riazuelo/bh/index.html

    • Re: (Score:3, Informative)

      by Radtoo (1646729)
      Not ethical? Why should this person be credited?
      Is the program code taken from Alain Riazuelo, or did he perhaps invent the theory behind Black Holes that made it possible to write the program from the article?

      Because what is asked in research is only that the persons whose work the current publication is based on are credited, both for the sake of their achievement and to enable verification of theories that isn't only superficial (current publication).
      • Re:Not new (Score:4, Insightful)

        by gardyloo (512791) on Sunday February 14, 2010 @05:08AM (#31133462)

        Perhaps, but it's common (and, I would argue, right) to mention work which has gone before, whether or not it was exactly the same. It gives alternative routes of learning about the given subject (which is, after all, the whole point of publishing results in the first place, right?). Sure, if the work isn't immediately applicable, then do it in a footnote or appendix, but unless one is totally unaware of the previously published (or even unpublished) work, it's better to be comprehensive than parochial.

  • What, they can't directly apply the compression methods they're simulating and create a 1byte file from the entire zip?
  • by dlawson (209945) on Saturday February 13, 2010 @10:57PM (#31132266)

    It's posted on Youtube here:

    http://www.youtube.com/watch?v=uNc-JLysk9Y&feature=related [youtube.com]

    Watch 'til the end, the terminology is nothing short of cosmically hilarious.
    Dave Lawson, astrogeek.

  • I was expecting to see the stars distort and stretch as their image approached the black hole in the rotation movie. Instead, while they "realistically" move around the hole, we don't get to see the full effect of gravity's refraction.

  • by ScrewMaster (602015) * on Saturday February 13, 2010 @11:32PM (#31132408)
    This definitely qualifies as "News for Nerds".
  • In my eyes, in disposed, In disguise as no one knows
    Hides the face, Lies the snake, the sun in my disgrace
    Boiling heat, summer stench 'neath the black the sky looks dead
    Call my name through the cream and I'll hear you scream again

    Black hole sun
    Won't you come
    And wash away the rain

    Stuttering cold and damp steal the warm wind tired friend
    Times are gone for honest men and sometimes far too long for snakes
    In my shoes walking sleep in my youth I prayed to keep
    Heaven send, Hell away

    __No one sings like you anymore_

  • TORRENT (Score:5, Informative)

    by shaitand (626655) on Saturday February 13, 2010 @11:55PM (#31132508) Journal

    http://www.rentalgeek.com/downloads/ibhs.torrent [rentalgeek.com]

    This has full data file, linux binary, and windows binary.

    Also, this has been uploaded to Elbitz if you prefer private tracker.

    • Re: (Score:1, Funny)

      by Anonymous Coward

      Excellent!
      Thanks to these naive coders, I am now one step closer to my black hole machine!
      Igor! Bring me my laughing flashlight! Muahaha!

  • Which is interactive, the black hole or the simulation?
  • 50 replies already and not a single "your momma's so fat.." joke! Jeez!
  • ...But all you have to do is create one to put the bin files in.
    • by Anonymous Coward

      It still doesn't work after that.

    • by netflix (1367097)
      Yeah this doesn't work for me either. Anybody have any ideas?
      • by linest (157204)

        I know this is going to sound like a troll, BUT...

        I compiled the Linux version and untarred the data tar file. It worked.

        I downloaded the Windows version and created a data directory and put the data files in there. Nope, doesn't work.

  • Strangely enough, it uses the same code library as the Fed Budget Simulator.

  • It's called a light switch.

  • I would love to see the funding justification for this work. Not being snotty, I just want to know how to get research dollars for things that appear to have no practical purpose.
    • by Legion303 (97901) on Sunday February 14, 2010 @02:18AM (#31133046) Homepage

      I imagine you would first have to move to Germany, then get a job at the University of Stuttgart. Then ask the German government for funding before someone reminds you that universities provide their own funding and usually don't require much justification for the research they choose to produce.

    • Re: (Score:1, Insightful)

      by Anonymous Coward

      WTF? I would have thought you weren't being serious, except for your "not being snotty" comment.

      A lot of science is already thick with impenetrable equations and difficult papers that, while perhaps containing significant results, are read and understood by, at best, several dozen others who are also in the field.

      Sometimes the best way to understand something is with visualization. And visualization can be one of the best ways of getting people interested in a field. There will be students that see this

    • I can assure you that no single research dollar has gone into this. It's all payed in euros.

  • I would hope for the sake of accuracy, the program completely freezes when the viewer hits the event horizon.

    • The observer only freezes at the event horizon as viewed from asymptotic infinity. From the point of view of the observer themselves there's nothing special happens at the event horizon -- it just looks like normal space. (It's a basic tenet of general relativity that you can always remove the effects of gravity locally; that's why singularities are such a problem, because the theory itself breaks down. If an event horizon *did* fuck up for an observer falling over it, something would be very wrong with the

    • I would have liked it to model the process of a black hole eating the earth if the large hadron collider actually did create a black hole.
  • I assume the observer is just a normal one-eyed camera. What I don't get then is the way the distortion looks. I've just seen the vids. As you approach, the border of the blackhole starts to deform from the shape of a circle to something else. Top,bottom, left, right of it get flattened. How can that be ? The blackhole has the shape and symmetry of a sphere and if the view is centered on it, its border has to stay a circle, because neither that object nor the camera introduces some horizontal and vertical
  • i used to have a nightmare where the sky would turn completely black because of a black hole. I would wake up sweating in the middle of the night and would freak out like a paranoid schizophrenic. This article does not make me feel any better
  • Time effects.

    Your time would accelerate very fast, when you would approach the black hole. I would not be surprised if you would never ever actually reach the center. As time outside would become so fast, that you would see the (distorted) end of the universe before your eyes. If you would survive until then, that would be extremely cool though. Certainly a better way to die than slowly getting eaten by cancer.

    Also I recommend having a radio stream coming in from the outside, so you could hear the accelerat

    • Re: (Score:3, Insightful)

      by kvezach (1199717)
      If that's true, how can black holes grow at all? The time dilation effect would seem to suggest that nothing ever reaches the event horizon, because time slows down so it falls increasingly slowly towards the hole. Something must be wrong, because black holes can grow -- but what is it?
      • The explanation I've heard is that from the viewpoint of the outside universe, the matter falling into the black hole will stop radiating visibly at all, due to being red-shifted into nothingness, so it becomes indistinguishable from the black hole from both an emissions standpoint and a gravity standpoint.

        I found that explanation vaguely unsatisfying.
        • Re: (Score:3, Interesting)

          by Tim C (15259)

          Well that would happen at the event horizon, which by definition is the "edge" of the black hole anyway.

      • Well, the matter falling in has its own gravity as well.

        For simplicity, let's assume that there's a perfectly symmetric shell of matter falling into the black hole, and for some strange reason it remains spherically symmetric (and I'll also assume a non-rotating black hole, which is also spherically symmetric). Remember that for spherically symmetric mass distributions, outside of the mass it looks exactly the same as if the whole mass were concentrated in the center.

        Now, for this scenario, the whole space

      • by Bemopolis (698691)

        The time dilation effect would seem to suggest that nothing ever reaches the event horizon, because time slows down so it falls increasingly slowly towards the hole.

        Clocks always run at the same rate in a given frame for an observer in that frame. It appears to take an infinite amount of time to an external observer. Hence the term "relativiity".

      • by Khashishi (775369)

        You have to think of spacetime as a malleable thing. You can end up inside the black hole before you fell into it. From your vantage point, you just fall in and quickly hit the center. During your journey, you cross over imaginary lines which represent the passage of time as recorded by an observer far from the black hole. When you start out far from the hole, you are crossing over each 1 second demarcation line every second on your clock ("proper second"). But the lines appear in increasing density nearer

        • by Khashishi (775369)

          The other frozen star theory is that black holes never fully form, but as matter accumulates, it asymptotically approaches the state known as a black hole. Eventually, it's indistinguishable from a black hole, although it never quite reaches the "ideal" black hole.

    • This provides a way to perform a computation of infinite length within a finite interval [wikipedia.org] (from your point of view). Of course, you have to count on the (external) universe sticking around and powering your machine forever, which doesn't fit with our current theories. You also have to launch yourself into a black hole to take advantage of this. Most users aren't ready to make that much of a commitment to one platform.

  • Most black holes are surrounded by an acceleration and (if the rotation direction of the black hole differs from that of the disk, a recent paper suggests) two jets at the poles. This makes the picture a whole lot less peacefull as given in this simulation. When approaching a black hole you probably die from radiation long before the stretching effect of approaching the event horizon.
  • It ran on my laptops geforce 9100m /w 256mb shared memory, but fairly slowly. If you have a midrange videocard with only 256, give it a shot. Pretty neat simulation actually.....

  • by Jon Abbott (723) on Sunday February 14, 2010 @11:37AM (#31135062) Homepage

    That black hole in the video looks almost exactly like Giedi Prime [wikia.com] from Dune...

  • #To avoid slashdotting, I've transcoded this simulation into a Web 2.0 application. Try it out now!

    <html>
    <body bgcolor=0>
    </body>
    </html>
  • When I run the simulation under windows, I just get this blue screen? Does this mean there is a small black hole in my PC?

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