Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×
Space Science

Missing Matter, Parallel Universes? 154

Phoghat writes "Could mirror universes or parallel worlds account for dark matter — the 'missing' matter in the Universe? In what seems to be mixing of science and science fiction, a new paper by a team of theoretical physicists hypothesizes the existence of mirror particles as a possible candidate for dark matter. An anomaly observed in the behavior of ordinary particles that appear to oscillate in and out of existence could be from a 'hypothetical parallel world consisting of mirror particles,' says a press release from Springer. 'Each neutron would have the ability to transition into its invisible mirror twin, and back, oscillating from one world to the other.'"
This discussion has been archived. No new comments can be posted.

Missing Matter, Parallel Universes?

Comments Filter:
  • by Akido37 ( 1473009 ) on Tuesday June 19, 2012 @05:37PM (#40376833)
    And in this parallel universe, everyone has a goatee.
  • Home of the Evil Spock.
  • I guess I'm my own invisible mirror twin then?
  • I believe they're talking about mirror matter. It's still in this universe but doesn't really interact with anything else, kind of like, oh dark matter is suppose to. :) So rather than new particles, they're existing particles but with a reversed parity. I'm not really sure how this would account for how dark matter is distributed differently than normal matter since I would think it would pretty much clump together to form the exact same structures as normal matter would. []

    • by FrootLoops ( 1817694 ) on Tuesday June 19, 2012 @07:26PM (#40378359)

      Yes and no. Your link refers to mirror matter based only on parity symmetry while I believe the paper at hand is more general. The arXiv preprint [] discusses this at the start:

      Concerns about parity are irrelevant for our following discussions: they extend to a parallel sector (or sectors) of any chirality. Nevertheless, in the following we shall name the twin particles from the `primed' parallel sector as mirror particles.

      To set things up, imagine stepping through a mirror and doing some physics experiments. You would expect everything to work out the same as before so long as "left" and "right" were reversed (...along the axis normal to the mirror...). That turns out not to be the case, which was surprising--some decades ago a few experiments with relatively exotic particles didn't work out as expected (brief history here []). Thus matter "through the mirror" and "before the mirror" are distinguishable. It's possible that matter through the mirror exists in our before-the-mirror universe, though it shouldn't interact much with the matter we're used to because the force-carrying particles need to be mirrored as well which ends up leaving only gravitational interactions. As you may have guessed, this is a potential candidate for dark matter. The lack of electromagnetic interactions would prevent distant mirror matter from being seen, and the lack of strong or weak interactions would nix many lab tests (like those that detect neutrinos, which are detected by their weak interactions).

      My (poor) understanding of the paper is that they consider an essentially arbitrary parallel universe with wimpy interactions with our own universe (except gravitationally), not necessarily just one created by parity changes. In particular they focus on transitions of neutrons from our universe to the parallel one and use such transitions to explain an anomalous dependence on magnetic field direction in a previous experiment.

      As usual, caution is the best plan. The authors call for more experiments, and I'm sure there are numerous explanations for their results that don't require (IMO) spooky transitions between parallel universes.

      • And remember: its difficult and dangerous to travel between universes if you haven't got someone who has been treated with Cortexiphan with you.
    • Re: (Score:2, Insightful)

      Is it possible that dark matter, dark energy, black holes and the Oort cloud don't exist at all, but are fanciful constructs that are required to explain certain observations according to currently “accepted” cosmological theories? There is a theory based upon known laws of electricity, that can explain the all observations without resorting to these esoteric constructs, which are nothing more than mathematical fiction. When the accepted picture of the universe put the Earth at the center, it al

      • Is it possible that dark matter, dark energy, black holes and the Oort cloud don't exist at all

        For dark matter and dark energy, yes, it is quite possible. But that possibility is becoming smaller near daily, with new observations. For black holes and the Oort cloud, no, and you should get more recent news.

        There is a theory based upon known laws of electricity, that can explain the all observations without resorting to these esoteric constructs

        No, there isn't. There is a theory pushed by some people that tri

        • by huckamania ( 533052 ) on Wednesday June 20, 2012 @02:31AM (#40381531) Journal

          So, limiting the discussion to dark matter and dark energy, which are still open to debate, it would be nice to have a score card of what is in and out.

          WIMPs are out.
          Mirror matter in and out, apparently.
          String theory, in then out then in but not nearly as cool as it was the first time.

          My theory is that fundamentally the big bang theory is mis-understood. The universe, as we know it, is currently under construction and subject to change. Not on human time scales, but if we wind back the clock and play it forward, the universe has been getting weirder. Look at the growth of the periodic table since the beginning of the Universe, the birth of protostars and galaxies, etc. I don't see why it isn't capable of continuing to increase in weirdness.

          This begs the question of how is the Universe getting weirder. This is where the big bang theory draws dragons and warns of impending doom. I like to think of it as if two water droplets were coming together. One is red, one is blue. When they mix, they create a Purple center. Our Universe is the purple part. From inside the purple part, you can't see the red and blue Universes and it would appear, if you wound back the clock, as if the Purple Universe appeared out of nowhere and it would also appear as if the Purple Universe was not only growing, but the growth would be accelerating. This doesn't break the big bang theory and doesn't break any other known theories. It does remove the need to explain expansion and other observations.

          Is that any stranger than mirror matter or string theory?

          • by dentin ( 2175 )

            Your score card is hosed:

            WIMPs are hypothetical, and neither in nor out.
            Mirror matter is hypothetical, and neither in nor out.
            String theory is untestable, and is a hypothesis, not a theory.

            As for your theory, it's not even a theory - it's an idea, and probably hasn't even reached the hypothesis stage, much less the theory stage. A theory has to be testably disprovable: for a hypothesis to become a theory, you have to define observations or tests capable of disproving it. (Note that a theory has to be dis

    • Also, according to the article (I haven't read the original paper), neutrons can oscillate back and forth between the two "universes" every few seconds. So there really is a constant interaction and flow of information between the two sets of particles. It may be "weak" on the scale of other interactions, but it's far stronger than what people usually have in mind when they talk about "parallel universes".

  • Socks (Score:5, Funny)

    by Russ1642 ( 1087959 ) on Tuesday June 19, 2012 @05:48PM (#40377033)
    The missing matter is all in the form of single unmatched socks.
  • by overshoot ( 39700 ) on Tuesday June 19, 2012 @05:48PM (#40377041)
    ... is the observations that dark matter not only doesn't interrupt with electronic matter (except gravitationally) but also doesn't interact with itself.
    • Maybe what was seen was antimatter in two different parallel universes?
    • dark matter... also doesn't interact with itself.

      Care to cite a source to that effect? It's a very strong statement. The paper specifically says the mirror matter interacts with itself in ways exactly analogous to regular matter:

      There may exist a hidden parallel gauge sector that exactly copies the pattern of ordinary gauge sector. Then all particles: the electron e, proton p, neutron n etc., should have invisible twins: e', p', n', etc. which are sterile to our strong and electroweak interactions (SU(3) x SU(2) x U(1)) but have their own gauge interactions (SU(3)' x SU(2)' x U(1)') with exactly the same couplings.

      and it also says that mirror matter is a good candidate for dark matter:

      Mirror matter can be a viable candidate for dark matter

      Unless you have something particularly compelling, I'm going to go with the pros on this one and call BS on your statement.

      • Care to cite a source to that effect?

        You can read more at Starts With A Bang, but the bullet cluster galaxy collision is a good demonstration: the electronic matter of the two galaxies is slowed by the collision, and the dark matter of the two keeps on keeping on. If the dark matter could lose energy in a collision the two dark masses would not continue unaffected.

        • Alrighty. After looking into it a little more, it seems the strongly self-interacting dark matter idea isn't terribly popular for a variety of reasons. The paper's suggestion that dark matter is so similar to regular matter is rather strange in that context.

  • Can someone with a good understanding of physics explain whether anti-matter could be a possible answer to this question?
    • by Qwertie ( 797303 )
      Well, let's say there is a kilogram of antimatter floating through space and it hits Earth.

      The antimatter is annihilated in an explosion of 180,000 Terajoules of energy. Oh, and some of Earth too.

      There can't be much antimatter in the universe because it explodes on contact with any matter it touches. Given e=mc^2, one kilogram of antimatter plus one kilogram of matter equals 2c^2 = 18e16 joules of energy = 180,000 TJ.

      IANAP (I am not a physicist, grain of salt etc.)
      • And never forget when dealing with kilos of antimatter: The explosion above Hiroshima was the equivalent of less than half a gram of antimatter annihilating less than half a gram of matter. You are proposing an annihilation reaction of about 2000 times that.
  • I have a theory on parallel universes.

    And that's that if you have to invent the notion of a parallel universe to explain your own theory, then I think that there's a pretty good chance that your theory is bupkis. It's time to start over, examine the evidence that you have, and come up with a new theory.

    Because when you add parallel universes into the mix, literally anything becomes instantaneously possible, and inherently not falsifiable.

    For example... I can postulate that there are many multicolor

    • I'll pay you $100 for one of your dinosaurs!
    • Re: (Score:2, Interesting)

      by Anonymous Coward

      When cosmologists talk about parallel universes, they have a very precise meaning, not Star Trek kinda parallel universes. In this case, a parallel universe is a plane of spacetime that is an actual distance away (through one of the higher dimensions in, for instance, M theory). Some particles that aren't attached firmly to our plane can travel between them (gravity is thought to be weak because of this). So if a cosmologist says that a parallel universe might be the cause of some effect, they *probably* ha

    • Re:My own theory (Score:5, Insightful)

      by demachina ( 71715 ) on Tuesday June 19, 2012 @06:59PM (#40378079)

      I'm guessing the people who thought relativity and quantuam mechanics were bupkis probably used similar lines of reasoning.

      You might want to try reading Brian Greene's "The Elegant Universe" []. It a fairly approachable book on superstring theory and hidden dimensions for laymen.

      The theories are very elegant and well thought out but are inherently difficult to prove since the sizes of the things that need to be seen are so small that they are currently unseeable, or energies required are so huge we can't produce them, so there is currently no way to experimentally prove the theories. The main superstring theories suggest 10, 11 or 26 dimensions of which we can actually see only four.

      No one is advocating embracing superstring theory, hidden dimensions or multiverses as fact, since even their advocates know they are only theories, but neither should they be discarded as "bupkis" until they are disproved since they may be a way forward in understanding and resolving unresolved conflicts in quantum mechanics in particular. They are regrettably as difficult to disprove as they are to prove.

      I'm of the opinion if smart people want to keep thinking about these things they probably should. Just because they are very hard problems doesn't mean they should be given up on. If smart people like the people that wrote this paper can figure out novel ways to test these hard problems, more power to them.

      • Relativity and quantum mechanics has been experimentally tested. It used to be that ALL science was done by experimentation and observation. Unfortunately, nowadays cosmology is mostly mathematical modeling using powerful supercomputers. These mathematical models are getting increasingly complicated, in order to take into account many recent measurements and observations coming from modern telescopes and space probes. According to present theories, these models require esoteric, never yet discovered entitie

        • As I recall general relativity took four years to confirm experimentally from the time it was published in 1915 until observations of a full eclipse established that space did bend around the Sun. Some of the teams involved had flawed experiments which seemed to disprove it, and Einsteins hopes for a Nobel Prize were frequenty dashed when, for example, an attempt to observe an eclipse during World War I ended when the German team was arrested in Russia for espionage.

          One wonders how long it would have taken

          • Re:My own theory (Score:5, Informative)

            by FrootLoops ( 1817694 ) on Wednesday June 20, 2012 @12:03AM (#40380759)

            Just a minor note: Einstein won his Nobel for his work on the photoelectric effect (which ironically helped launch the quantum theory he distrusted the rest of his life), not for relativity. I'm not sure if you meant to imply that or not.

            • General and special relativity were cited in most of the nominations for his prize, and I think it had a clause citing his contributions to theoretical physics.

              I think there was still distrust of the theories on relativity in some circles at the the time so they gave it to him on a safer discovery though many of the people involved wanted him to get it for relativity.

              I could misremember though.

              • by dargaud ( 518470 )
                He should also have received it for his explanation of brownian motion, which relaunched the whole thermodynamics / statistical mechanics field. All those contributions in less than ONE year. And I'm still trying to make the front page of slashdot for the 2nd time in 20 years...
          • by Anonymous Coward

            Actually "hidden mechanisms" can be ruled out by experiment using Bell's inequality []

    • There is an alternate theory that explains all observations in terms of electric and magnetic laws that are well understood and used every day here on earth. Because electric forces are so much greater than gravity, electricity gets things done much faster. This causes a great conflict with theories that try to explain how things came into being by processes that take immense amounts of time. This electrical theory CAN be tested by experiment and observations.

      • There is an alternate theory that explains all observations in terms of electric and magnetic laws that are well understood and used every day here on earth.

        The way you phrase this - by saying it exists and mentioning its value and superiority, while carefully not actually describing it - reminds me of how those Amway people start every sales pitch.

  • Occam's razor (Score:2, Insightful)

    by slasho81 ( 455509 )
    My keys seem to be missing. I can't find them anywhere! Could they be in a parallel universe? They could, but it's far more likely I'm just too stupid to figure out where they are.
  • Sure. (Score:5, Funny)

    by Chrutil ( 732561 ) on Tuesday June 19, 2012 @06:27PM (#40377651)
    We read all this stuff trying to understand anything and all, and then the next paper they release will just say "Bazinga!"
  • Read the David Deutch books: "The Fabric of Reality" and/or "The Beginning of Infinity". Good "layman" descriptions of quantum theory and the possibility that we are indeed living in a multiverse where "our reality" intersects with many others . . .
    • Disagree. If it interacts *at all* with what we can observe and measure it's part of our universe.
  • How do we know that all galaxies are made of matter, and that the universe isn't littered with some galaxies made out of antimatter? How would we be able to tell if a galaxy was made of anti-matter due to a different rounding error than occurred in our neck of the woods?

    • by Anonymous Coward

      One problem: The space between galaxies isn't empty - there is material there, mostly Hydrogen. So any anti-galaxy would, on its edges, be interacting with the normal material that is between galaxies. The matter-antimatter reaction would produce x-rays, which we don't see.

      • It seems to me we're in highly speculative territory here.

        Firstly there's obviously very little matter in inter-galactic space, otherwise it would be too opaque to see galaxies billions of light years away, it's perfectly reasonable to assume any significant amount of normal matter near an anti-matter galaxy would have long-since been eliminated, so it would only be the occasional anti-atom that annihilates - in fact the vast majority of annihilation would probably occur deep in intergalactic space where th

        • Yeah, things would be slightly different if you assume entire clusters are made of antimatter. There are plenty of galaxy colisions on the sky, and none of them emmit the gamma (for closer ones) or X-ray (for distant ones) radiation we'd expect.

          But even with the cluster hypotesis (and assuming that earlier anihilations made enough pressure to completely separate the intergalatic matter from the intergalatic anti-matter) we'd have a problem, because there are cluster margers at the sky. Also, the simulations

          • Well, except for the fact that all our simulations require that the early universe go through a super-luminal expansion phase which we have no explanation for. Which actually introduces an additional possibility - that the matter-antimatter imbalance represents an uneven distribution in the first few moments, resulting in matter-dominated and antimatter-dominated regions which were rapidly carried so far apart that even light can't travel between them any longer.

            Also, unless you know something I don't our

    • Not a dumb question at all. If you're actually interested in discussing this sort of thing, one place to go is PhysicsForums. Here's a thread [] and paper [] on this topic. The general consensus is that annihilation events should be visible if a lot of the universe were made out of antimatter, but we don't seem to find any. (My very very unpolished view is that matter and antimatter were produced in slightly differing amounts for some reason during the universe's formation and the vast majority of both annihilate

    • by swalve ( 1980968 )
      What I always wondered was whether they had accounted for all the energy that exists "in transit". Every star in the universe has been putting out photons (and other stuff) since they first had their fuse lit. We only see the stuff that comes right at us. But the universe is literally bathing in photons traveling every which way, which we cannot see.
  • Sure neutrons have an aggregate charge of zilch yet quarks that make up the thing don't. We've been able to see fractional effects caused by constituents of neutrons for a while now.

    It would be really interesting to understand why being able to effect a neutrons properties with a magnetic field warrants such exotic explanations.

  • sounds like a syfy channel moive of the week

  • Was just hoping that meant only just another spatial dimention or other relatively cheaper alternatives. But if we have to make guesses, lets think big from the start.
  • I like this because unlike most candidates for missing mass, it can be falsified. Congrats to Berezhiani and Nesti for having the balls to propose something that other scientists can measure! It should be feasible to distinguish neutrons that decay, neutrons that hypothetically oscillate into a non-interacting state and back, and those that simply escape the trap.
  • The Crosstime Engineers are strip mining this universe. It's close, from an energy consumption point of view and has no advanced civilization to get in the way. The testing phase is over and full scale exploitation will begin shortly.
  • If dark matter is actually some effect of the relationship between matter in another universe and this, how is it that the two are typically linked gravitationally, but not always. If you look at this photograph recently taken by the HST [], one of the largest galaxy clusters we can see has its dark matter concentrated when the barionic matter is not. Puzzle me that? I'd have to have an explanation that would explain such anomalies.

  • Would not these parallel universes be somewhat coupled, then, because moving particle positions one place could affect the other place? And obviously position could transfer energy. Would a neutron within a black hole in one universe then be able to transfer energy into or out of the black hole by means of its parallel connection? But doesn't that violate some premises of black hole physics? And finally, would evil Kirk ever be able to overcome good Kirk and absorb his acting skills?
    • I first heard about it a decade ago. I think in "Scientific American" before Disney bought it out. That, and one of the early hard science fiction books of my youth presented this particular superstring theory as the explanation for dark matter, as the parallel worlds interact via gravitation but not electromagnetics.
  • I have an alternative theory. How often do you see a story saying "astronomers find out ____ is actually much bigger/smaller than they thought" or "____ actually has more planets orbiting it than we thought." So they're supposed to be counting all mass in the universe AND they're using almost exclusively reflected radiation to do it?! Dark matter is a math error, if you can even call it that when the error itself is thinking you can even estimate something that complicated with our crappy technology. Cre
  • Such a theoretical mass swap, particle replacement system would logically not result in more mass in our universe and less in another. It's a mirror, not a funhouse mirror.

    Let's say they do oscillate at 10 times per second and both particles exist together at some point because of an unevenness. Then with 10 particles, 5 would be unbalanced one way and one towards the other universe, as it is a cycle.

    So let's say it's a perfectly even system like two moons orbiting a planet. They're always offsettin
  • I know we keep looking for smaller and smaller bits of an atom, but if the neutron exhibits this behavior then Gravity as a weak force could be explained. If all the neutrons in a object were phasing in and out of our universe then their gravity impact on the object would be limited to the total neutrons and the force they can exert on the object while they exist in our dimension. Other parts of atoms do have mass, but this is interesting.

  •'s where my unpaired socks disappear.
  • Maybe Terry Pratchett and Stephen Baxter knows something we don't know []?

  • For a long period of time there was much speculation and controversy about where the so-called `missing matter' of the Universe had got to. All over the Galaxy the science depart-ments of all the major universities were acquiring more and more elaborate equipment to probe and search the hearts of distant galaxies, and then the very centre and the very edges of the whole Universe, but when eventually it was tracked down it turned out in fact to he all the stuff which the equipment had been packed in.

    There wa

  • I'm sick of parallel Bender lauding his cowboy hat over me!

Do not meddle in the affairs of troff, for it is subtle and quick to anger.