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Space Science

Doughnut-Shaped Universe Back In the Race 124

Posted by kdawson
from the mmmmm-universe dept.
SpaceAdmiral writes "The once-popular idea that the universe could be small and finite is making a comeback. Many researchers thought that a 'wraparound' universe would mean that distant objects would be seen multiple times in the sky, but new research suggests that a '3-torus' (or 'doughnut universe'), as well as other shapes, could fit our actual observations, particularly the WMAP data."
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Doughnut-Shaped Universe Back In the Race

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  • That's silly. (Score:4, Insightful)

    by ivanmarsh (634711) on Tuesday May 27, 2008 @05:22PM (#23562485)
    Though it's possible, how many other things in the universe are naturally doughnut shaped?

    • Re: (Score:2, Funny)

      And are soooo delicious.
      • by drik00 (526104)
        OK, i know i'm responding to a sig... but explain to me two things:

        1. how has it been decided that conservatism has failed since it was the government who has been slowly abandoning it? conservative ideals created the infrastructure of the country, and only since we've gotten so rich and fat and happy have there been such large steps away from those ideals, and look at what we're getting ourselves into now.

        2. communism and conservatism are nearly polar opposites, so what is the ideal solution?

        feel free t
    • by uberjoe (726765)
      Though it's possible, how many other things in the universe are naturally doughnut shaped?

      Besides delicious, delicious doughnuts? Mmmmmmmmmmmm . . . Forbidden Doughnut.

    • Re:That's silly. (Score:5, Informative)

      by wass (72082) on Tuesday May 27, 2008 @05:31PM (#23562611)
      It's primarily the boundary conditions that are leading to the 3-torus idea.

      A torus gives periodic boundary conditions in two dimensions. Periodic boundarty conditions for one axis can be thought of as curling a piece of paper around to make a cylinder. For someone on this paper, picture running on a soccer field, and if you run out of bounds on the left side you pop back in in the right side, aka pacman's tunnel. To make a torus, you'd need to wrap the top exposed circular edge to the bottom circular edge, in a donut way. You'd need to bend the paper to do this, so you'd really need something like a rubber membrane. But once you connect this, then you have a soccer field where when you kick a ball behind your opponent's goal, it comes out from behind your goal. That is 2-D boundary conditions. The simplest shape that can manifest these boundary conditions of a two-dimensional system is a torus, which exists in 3-D.

      Now extend this one step further. Take a 3-D space, and add periodic boundary conditions for left/right, back/front, and also top/down. This is the 3-torus that is discussed in the article. Someone confined to this 3-D surface has a full three independent degrees of freedom for movement, but the manifestation of this shape would look more complicated in four or five dimensions. But that is what is being talked about here.

      Of course in quantum cosmology there are other dimensions, such as the warped 5th dimension of the Randall-Sundrum model [wikipedia.org], which may or may not be periodic, and add to very peculiar topologies of the universe.
      • Re:That's silly. (Score:5, Insightful)

        by mikael (484) on Tuesday May 27, 2008 @05:50PM (#23562847)
        You mean we're trapped inside a giant Asteroids-3D screen level?
        • Re:That's silly. (Score:5, Insightful)

          by exp(pi*sqrt(163)) (613870) on Tuesday May 27, 2008 @06:03PM (#23563033) Journal
          Yes. There's no need for these long-winded explanations. Asteroids is played on a 2-torus and if it were a 3D game where going off the 'front' brought you on at the 'back' then it'd be played on a 3-torus. Interestingly, asteroids played on a circular screen where going off one side brought you back on the other would be on a completely different topological space, the cross cap [wikipedia.org]. But if you think about it there's an interesting issue with that: going off one side would bring you back on the other side reflected. There would be some pretty weird consequences if our universe were like that.
          • Re: (Score:3, Interesting)

            by spun (1352)

            going off one side would bring you back on the other side reflected. There would be some pretty weird consequences if our universe were like that.
            Wasn't there at least one short sci fi story about this? Someone gets rotated in the fourth dimension and comes back with their heart on the other side and severe gastrointestinal problems because all their molecules have different chirality.
            • by blincoln (592401)
              Wasn't there at least one short sci fi story about this? Someone gets rotated in the fourth dimension and comes back with their heart on the other side and severe gastrointestinal problems because all their molecules have different chirality.

              I don't remember the details, but one of Rudy Rucker's 'ware series involves a character being flipped on the W-axis as you describe.
            • by EdZ (755139)
              It's called Left to Right, was was written by Isaac Asimov.
              • I think HG Wells did something similar too.
                • Here it is! (Score:4, Informative)

                  by spun (1352) <(moc.oohay) (ta) (yranoituloverevol)> on Tuesday May 27, 2008 @08:27PM (#23564767) Journal
                  I just looked it up and you are correct. Here's what I found:

                  "There is no way of taking a man and moving him about in space, as ordinary people understand space, that will result in our changing his sides. Whatever you do, his right is still his right, his left his left. You can do that with a perfectly thin and flat thing, of course. If you were to cut a figure out of paper, any figure with a right and left side, you could change its sides simply by lifting it up and turning it over. But with a solid it is different. Mathematical theorists tell us that the only way in which the right and left sides of a solid body can be changed is by taking that body clean out of space as we know it,--taking it out of ordinary existence, that is, and turning it somewhere outside space. This is a little abstruse, no doubt, but any one with any knowledge of mathematical theory will assure the reader of its truth. To put the thing in technical language, the curious inversion of Plattner's right and left sides is proof that he has moved out of our space into what is called the Fourth Dimension, and that he has returned again to our world."
                  The Plattner Story [mtroyal.ca]

                  That was written in 1896, putting it 12 years after Flatland [google.com] which I think was the first treatment of the theme of the consequences of differing numbers of dimensions. Nothing new under the sun, eh?
              • by spun (1352)
                That's the one I was thinking of! I thought it was either Asimov or Bradbury but I couldn't remember which. I also read the Rudy Rucker novel that contains a similar bit, but I knew that wasn't the first treatment of the theme.

                Wow to HG Wells if he did it first (anyone know the name of the story?), though I would consider the general themes of 'consequences of different numbers of dimensions' as having been laid out in Flatland before that.
              • I thought it was "Mirror Image" by Arthur Clarke.
            • by dpilot (134227)
              It was also a feature in the novel, "Doorways in the Sand" by Roger Zelazny.

              SPOILER ALERT

              The protagonist has an alien entity riding (mostly benignly) inside him that needed to be rotated in the 4th dimension in order to become fully functional. It's a really bizarre and fun book, so it's not worth going any further than that with isolated plot-oids.

            • In a very old Star Trek novel, Spock Must Die [wikipedia.org], a modified transporter beam gets reflected, with the result that there are now two Spocks, one of which is reflected. Later, the crew uses the fact that the duplicate is synthesizing food for himself with the proper handedness in the amino acids, to tell them apart. I believe that's accurate - I think I read that book 30 years ago.
          • Wouldn't that be exactly a projective plane?
      • by msheekhah (903443)
        so kinda like this: take a tube sock. cut off the end. stitch the inside of the sock to the outside, so that when it flows around, you switch from the inside of the sock to the outside, and the crump it up in a ball... so that you would have to travel the "length" of the universe twice to return to the other side of earth? amidoinitrite?
        • Re: (Score:3, Funny)

          by SEWilco (27983)

          you would have to travel the "length" of the universe twice to return to the other side of earth
          No, the flights only seem to take that long.
      • by nguy (1207026)
        A torus gives periodic boundary conditions in two dimensions.

        A torus doesn't have a boundary, hence it doesn't have boundary conditions.

        What you are probably trying to say is that if you take a square and impose certain periodic boundary conditions, then you get something that behaves more or less like a torus. But what you have is a square with boundary conditions; the "boundary conditions" are related to how you choose to represent the torus, not to the torus itself.
      • by ivanmarsh (634711)
        Okay... I'm not going to pretend to understand how that would occur in the really real world but thanks for trying to explain it.

        It simply seems to me that if there was a big bang why wouldn't that bang simply produce a roundish or oval shaped universe? All other observable explosions expand from the center in a roughly uniform pattern.
      • So not only has Quantum Physics repeatedly proven that the computer running the universe in which we live works on integers for speed, that the universe simulator only refreshes things on screen [slashdot.org],
        but now we've also proven that it doesn't check for integer overflows ?

        Man, our universe is just such a buggy piece of code. Probably hacked together in Perl [xkcd.com].
    • What if it's actually a smaller part of a whole, and we only see it as a donut from the inside? The edges of our universe are inner surfaces... the edges of a splash from a raindrop in a puddle of spacetime.

      (If you didn't follow the metaphor, the raindrop impact would be viewed as the big-bang, and the edges would be formed by water surface tension, so the universe would continue to expand but not forever... eventually it would "pop" or disperse as the surface tension becomes too weak to fold things togethe
      • by tsalaroth (798327)
        So what you're saying is, one day "soon", we'll just cease to exist as all space-time and physics cease to function?
        • Re: (Score:2, Funny)

          by mOdQuArK! (87332)
          The scary thing is, this has already happened a few times, with each new instantiation of the universe being more bizarre than the last. :-P
        • I made no mention of timeframe, so no, I'm not saying that at all. If reality was anything like this random idea of mine, I think it's more likely that small pieces of spacetime would fall(?) back to the greater body of they were ejected from... I've no idea if that would be anything like our one though. If it was, we'd probably be none the wiser other than our large scale observations might change between times. No need for end-o-the-world panic.
        • Re: (Score:3, Funny)

          by rts008 (812749)
          No, we will all (and our universe) cease to exist in this form when some trans-dimensional cop dunks our donut universe in his coffee and EATS US!!!
    • by Ant P. (974313)
      How about magnetic fields.
    • Mmm, doughnuts...

      Now cue new prophets going on about the impending arrival of the Great Homer, whereupon our entire universe will be rendered into bite-size chunks and slowly masticated into elementary particles of deep-fried pastry goodness.

      Cheers,

      • by tbannist (230135)
        Don't forget the holy wars over whether the universe is "covered with sprinkles" or "filled with jelly".
    • Re: (Score:2, Informative)

      by docbrody (1159409)

      Though it's possible, how many other things in the universe are naturally doughnut shaped?
      uh, possibly almost everything (at least at the quantum level). -string theory. google strings vs. loops, or strings meet loops.
    • by pla (258480)
      how many other things in the universe are naturally doughnut shaped?

      How many cells in your body have a bipedal shape? How many things in your car look like your car itself? How many 2x4 lego bricks look like a castle or death-star or robot?

      "Greenness dissolves" applies outward as well.
    • by BPPG (1181851)
      maybe think less doughnut-shaped, more ring-shaped. There's tons of things in nature and astronomy that are ring-shaped. Doughnut-shaped can't be that much of a stretch.
    • by FreeFull (1043860)
      Doughnuts are naturally doughnut shaped.
    • Well, quoit.
    • Though it's possible, how many other things in the universe are naturally doughnut shaped?
      Perhaps the universe is naturally round and mostly flat (like a disk), but has a gigantic black hole in the middle. That would result in a donut shape.
      • by ivanmarsh (634711)
        That was my only conception of it... if the universe is expanding from the equivilent of an extra-universal black hole and the universe we observe is held in place by the equivilent of the Earth's magnetic field... but then that's based on very little understanding of wheather something like that is even possible.
    • Many particle accelerators are doughnut shaped; indeed, it is speculated that God used a particle accelerator to create the universe.

      While scientists disagree over exactly what the universe's origins are, religion has provided a consistent answer since the Earth's beginnings, over 6,000 years ago.

      Also naturally doughnut shaped:

      Anii
      Cheerios
      Red blood cells
      This. [gizmodo.com]
      This too. [goatse.cx]
      Can't forget this. [prostate.org.au]
      There is also an argument to be made that earthworms are doughnut-shaped when viewed end-on, and further that most life form
  • by CrazyJim1 (809850) on Tuesday May 27, 2008 @05:23PM (#23562493) Journal
    "Your theory of a donut-shaped universe is intriguing, Homer. I may have to steal it."
  • by Anonymous Coward
    I guess it depends on your perspective. It looks like a goatse universe to me!
  • by NecroBones (513779) * on Tuesday May 27, 2008 @05:39PM (#23562711) Homepage

    I'd love to read it, but... what's with all these pay-to-read links lately?

    $8 for an article? Most magazines cost less.
    • by SpaceAdmiral (869318) on Tuesday May 27, 2008 @05:46PM (#23562799) Homepage
      Ha! When I submitted it it was available for free. They must have changed it when they noticed all the /. traffic.
    • it's nature.. you pay to have your stuff put in it so other people can pay to read it. Think of it as a paid for nutjob filter (it's meant to keep them out). They are all well and good if you belong to an achidemic institution with a subscription but if you are not at that stage in your education and just end up at their door through curiosity or as extention of your existic studies it can be very infuriating. For example I found getting hold of a paper published in 1928! on the origianl usage of a volta
      • Re: (Score:3, Insightful)

        by Metasquares (555685)
        I could understand that rationale if the peer reviewers were paid employees, but they aren't, at least for most journals; they're unpaid volunteers.

        (Moreover, I don't think the screen they provide is particularly useful - in fact, I think it's even harmful because it imposes a socially constructed restriction on one's exposure to new ideas - but that's just my own opinion).

        In the case of Nature, I think most people pay to have their work in it because of the prestige of having an article published in Nature
        • by LurkerXXX (667952) on Tuesday May 27, 2008 @09:58PM (#23565581)
          One of my old mentors was the editor of a journal. He had a secretary who was paid by the journal because there is a boatload of work to do in managing submissions, finding reviewers, sending copies of submitted articles out to them, bugging them to get in their reviews, sending out critiques to submitters, checking rewrites, resending out answers to criticisms,etc, etc, etc. Editors also get pay, because it sucks up a LOT of time. Much more than reviewer time, which can already be a lot for some folks.

          So there are defiantly costs involved. There's also the salary for the folks working the presses making the dead-tree copies. Magic faeries also rarely run the journals website. I know I'd want to be paid for running it. Wouldn't you? So there are lots of costs involved. The publishing companies also want to make a profit on top of that. Now I won't argue with you about how much profit the publishing companies should make off it. Just wanted to point out that there are very real expenses involved in making a journal, even with free reviews.
        • I could understand that rationale if the peer reviewers were paid employees, but they aren't, at least for most journals; they're unpaid volunteers.

          The business model is on its way out, open access journals are taking over. There are several reasons for this:

          1) Many scientist recognize open access [wikipedia.org] is the right way to do science.

          2) Open access journals tend to have higher impact factors. The impact factor is a measure of how important the journal is, and is mostly measured from number of citations from the journal. Open access journals gets more citations, because they are easier to find with a web search.

          3) Many funding agencies have started requir

        • by tgibbs (83782)

          (Moreover, I don't think the screen they provide is particularly useful - in fact, I think it's even harmful because it imposes a socially constructed restriction on one's exposure to new ideas - but that's just my own opinion).

          There is nothing to stop anybody from publishing an unreviewed journal. There are many laxly reviewed journals, but they are not widely read. There are also journals that specialize in speculative ideas. Again, they are not very widely read. The fact is that in science, as in most fields, ideas are cheap. Most scientists have more ideas than they have time to pursue. What is valued is ideas that are supported by well thought-out, carefully done experiments. Given limited time, most scientists favor a journ

  • by hyades1 (1149581) <hyades1@hotmail.com> on Tuesday May 27, 2008 @05:49PM (#23562831)

    "...new research suggests that a '3-torus' (or 'doughnut universe'), as well as other shapes, could fit our actual observations..."

    Great...it all ends when we wind up being eaten by some fat-ass cop from the other side of a black hole.

  • by peter303 (12292) on Tuesday May 27, 2008 @06:01PM (#23562999)
    Right in the very middle.
  • by frovingslosh (582462) on Tuesday May 27, 2008 @06:01PM (#23563011)
    To read this story in full you will need to login or make a payment

    So what's the point in running this if we have to pay to RTFA? Supposedly anyone already paying is likely to read it anyway, so the only ones this posting is for is for those who do not already subscribe to the site. In a world where information wants to be free, I hardly see it as appropriate for Slashdot to hype up a pay site. Were there no interesting articles on any free sites today? Or did Slashdot get a payment for posting this advertisement for this pay site? Did paid subscribers to /. also see this ad sneakily disguised as an article (if so I bet they resent it even more than I do).

    • I think it is completely reasonable for slashdot to assume a base level of resources available to its user base. In this case, the presumed user base is everyone who knows ANYBODY attending ANY college. Pretty much every university provides off-site journal access to their students (whether the students know about the service or not). I think that covers most everyone here.

      Additionally, when a college subscribes to journals, it usually subscribes to hundreds or thousands. It seems a bit naive to say:

      S

      • College (Score:1, Troll)

        by Mark_MF-WN (678030)
        Yeah, because 100% of nerds (the target audience of slashdot) are in college. I like how your moronic prejudice rules out anyone who is a) still in high school b) out of college It's not like it's unusual to be so long out of college that one's entire peer group is also out of college. In fact, this typically happens with a few years of graduating. Which leaves an entire decade of nerd-life before one would have free access to journals, and five or six decades of nerd-life after the period in which one
        • Since neither of my posts seems to convey that I don't expect the entirety of /. to be in college, let me spell out my views even more clearly with a personal example.

          To access an article for the next few decades, I won't even have to leave the family. I'll have a regular enough supply of college-age first cousins (assuming half of them go to college) to supply me with any journal access I might need for 2/3rds of the next couple decades. By that time, I expect to have produced a couple college age kids

          • Ah, the classic argument of the intellectually incompetent: using a single case to prove a general principle.

            But if really think that single examples prove something, let me use myself as a counterexample.

            I'm the only person in my extended family who is in college right now -- and my college is very small and doesn't provide access to stuff like that from outside the intranet. There's only one person in my family who does research, and he and I don't speak. My friends in college were mostly lit and b

      • by Magada (741361)
        Bollocks, mate.
    • by Anonymous Coward
      FWIW, here's the preprint [arxiv.org].
    • You're a glass half empty kinda guy aren't you? I see this as an opportunity to have a legitimate excuse not to RTFA. I'm a cheap bastard.
  • Apparently we'd all be much happier of we had our minimum of 17.3 glazed per day!

    http://www.sfgate.com/cgi-bin/article.cgi?file=/comics/Zippy_the_Pinhead_Color.dtl

    -WtC
    • by Muad'Dave (255648)
      The last time I ate 17.3 glazed "Hots" [krispykreme.com], I was escorted from the building for planting myself at the end of the donut conveyor [krispykreme.com] and opening my mouth extra-wide.
  • I have some questions for the cosmologists among us.

    When talking about a closed (positive curvature) geometry like the one described here physicists say that the universe will have enough mass to eventually stop expanding and then begin to collapse on itself. However, when I imagine a 2D version of this I see a circle expanding on a sphere (or donut) until it wraps around, at which point the mass will recollect on the opposite side. In that model, the universe isn't so much stopping expansion, but continuin
    • Re:Questions. (Score:4, Interesting)

      by esampson (223745) on Tuesday May 27, 2008 @07:21PM (#23564075) Homepage

      ...Or is the idea of an edge just not valid? ...

      It isn't valid because a 3-torus is a 4 dimensional shape. To be more accurate it is valid, but not in a way you can conceive of.

      Think of it in these terms; you are a two dimensional creature. Your world is defined solely by X and Y coordinates and is of a finite size. Take two opposite sides and bring them together and now your world is a tube. The only edges you can perceive are the ends of the tube. Take the two ends of the tube and bring them together. You are now living on a standard torus (not a 3-torus). As far as you are concerned there is no "edge" to the torus. Roam as much as you want to but you will never reach an edge. The only way for you to experience an "edge" would be if you stepped up one dimension and became three dimensional.

      A 3-torus is a similar construct but instead of being a two dimensional world with the X edges and the Y edges brought together it is a three dimensional world in which the X edges, Y edges, and Z edges have all been brought together. From your three dimensional perspective there is no "edge" and the only way to perceive one is to step up a dimension and become a four dimensional entity.

      • by antikaos (1166401)

        ...step up a dimension and become a four dimensional entity.

        Five, we're already four dimensional.
        • by esampson (223745)
          Well, true, but we are four dimensional in the same sense that the creature living on the torus is really three dimensional, since the surface of the torus is not flat. When I speak of becoming a four dimensional entity it would be more correct to say you need to become a fully functional four dimensional entity, most likely with a fifth dimensional warpage.
      • From your three dimensional perspective there is no "edge" and the only way to perceive one is to step up a dimension and become a four dimensional entity.
        Or to travel far enough that you return to your origin. (Though debate over this point is the point of TFA)

        - RG>
      • It isn't valid because a 3-torus is a 4 dimensional shape.

        Nonsense. A three-torus is, just like a three-sphere, three-dimensional.
      • your world is a tube
        So the universe is a series of tubes?
      • [T]he only way to perceive one is to step up a dimension and become a four dimensional entity.
        ...which, as your post is written without including yourself among us three-dee mortals, you have obviously done. What's the secret? Or is it something that involves long years of meditation and fence-painting? Because it'd be cool to see the edges of the universe and whatnot, but probably not worth all that trouble.
        • by esampson (223745)

          ..What's the secret? Or is it something that involves long years of meditation and fence-painting?...

          Unfortunately I can tell other people how to do this. It was the result of an irreproducible accident that involves a coronal mass ejection coinciding with two charged particle beams traveling in opposite directions, an intense magnetic field, a crossed proton stream and a case of non-dairy creamer.

    • It isn't your idea of an edge that is invalid, it is how you are viewing expansion that is invalid.

      You equated expansion to a circle expanding along the surface of a torus, then meeting on the other side. Your example is of an object exploding within a toroidal surface. Similar to, but not the same as, a one dimensional universe expanding within a 2 dimensional toroidal surface of fixed size.

      The expansion of the universe is the torus itself getting bigger. Draw a few dots on a balloon, put a C clamp in th
  • Giant Telescopes... (Score:2, Interesting)

    by jaminJay (1198469)
    I have some faint recollection from the early 90's that, during WW I or II (or both?), their was some research into the building of a telescope powerful enough that, when pointed straight up, would look right out the 'end' of the universe and in the other in order to spy directly on the exact opposite side of the planet. Now, to search for any links to back that strange memory up...
    • Even leaving aside the practical issues, the best theorical result you could have this way would be tens of billions years outdated.
  • Remember a cruller [wikipedia.org] is a donut too. Does this mean that parallel universes may be donut holes?
  • Since the article is available on pay only, could someone please explain why the universe may not be a hall of mirrors, even if it wraps around?

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