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Space Science

Before the Big Bang: A Twin Universe? 212

esocid writes "Until very recently, asking what happened at or before the Big Bang was considered by physicists to be a religious question. General relativity theory just doesn't go there — at T=0, it spews out zeros, infinities, and errors — and so the question didn't make sense from a scientific view. But in the past few years, a new theory called Loop Quantum Gravity (LQG) has emerged. The theory suggests the possibility of a "quantum bounce," where our universe stems from the collapse of a previous universe. This may be similar with beliefs of Physicist Neil Turok of Cambridge University who has theorized about a cyclic universe, constantly expanding and compressing."
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Before the Big Bang: A Twin Universe?

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  • by Anonymous Coward on Wednesday April 09, 2008 @09:28PM (#23019786)
    he got her really drunk.
  • by bcat24 ( 914105 ) on Wednesday April 09, 2008 @09:34PM (#23019842) Homepage Journal
    The universe is safe for you and me, but what of Lazarus?
  • Considering approximately 5% of Physicists in the Unites States are religious I dont think they considered it a religous question.

    If the likes of stephen hawking and albert einstein with general reletivity cant work it out how are illiterate goat herders from 2000 years ago supposed to have done it?
    • Re: (Score:3, Funny)

      Citation needed []
      • Here you go. []

        Surprising finding, actually (assuming we take 1998's results as fairly representative of what today's should be).

        I'd say the breakdown of scientists that I've known is more like 50-50.
    • by Max Littlemore ( 1001285 ) on Wednesday April 09, 2008 @10:18PM (#23020068)

      There are different kinds of intelligence. Some people can solve complicated problems like getting laid but can't handle simple problems like calculating pi to 15 places using a couple of paper clips a rubber band and a slinky. This doesn't make them useless to society, and I think we should celebrate our differences.

      To look at it another way, Einsein supposedly intuited a lot of his work and then proved it later. He had that kind of mind. If Einstein had been a goat herd 2000 years ago, the accepted mode of proof would have been vastly different, so proof from them rates as primitive religion now just as general relativity is the superstitious mumbo jumbo of the future. I'd take you in my time machine to prove it, but it only seats one and I know you're prone to not returning them... or will be on July 12th, 2017.

      Also, Einsein was wrong about a whole lot of stuff, but that doesn't make his contribution useless. Ditto for the goat herders.

      If someone does finally work it out, kill him. Until then, being open to the idea that someone who can't read or write but can play world class lawn bowls probably has as much, if not more insight into the true nature of nature than Hawking et al is a healthy perspective.

    • Considering approximately 5% of Physicists in the Unites States are religious

      Every physicist I've ever met adheres to the cosmology of one religion or another, if only by way of personal suspicion about what science cannot answer.

      And those friends of mine who have worked with far more physicists report that they often find fundamental reason for what is essentially religious belief in their work. You know, kind of like Einstein, who was "religious" in the sense that he believed in a fundamental and purposeful (deterministic) order, rather than the stark random chance esposed by th

      • Re: (Score:3, Insightful)

        Science and religion don't have to be mutually exclusive. It is entirely possible for God to obey the laws of physics (or create them, for that matter). Arguments about whether this theory or that law proves or disproves the existence of God are stupid - for example, it is possible that God decided to create man through evolution.

        I, too, know many scientists who are actively religious. Most of them say things along the lines of "my studies in field X have opened up to my mind the glory of God" or "the un
        • i think the conflict arises when science contradicts the particular holy texts of a religion, rather than the notion of a god. But that is only really a problem for biblical literalists or their equivalents, which from what you've said, i assume you aren't one of.
          • Re: (Score:2, Insightful)

            That in and of itself is only a problem when people blindly follow a particular translation of their holy text rather than try to discern what the true meaning of the text was in its original language. For example, to understand the prophecies of Isaiah, one must understand Jewish culture in the time of Isaiah. To understand the Mosaic Law, it is highly useful to understand the world at the time of Moses. And so on and so forth.

            Many people forget that, and they assume that their version of the Bible is c
        • God is just a meme that people get infected with. The first job of the meme is to protect itself from destruction, in fact religion is the definition of a successful meme. Its hardly surprising that we can reconcile anything from cosmology with religion. It would be a pretty crap religion if it couldn't worm its way into compatibility in our heads.
        • This is wrong. Science is the complete counter-point to religion. Your argument about a "god" creating the laws of physics IS a way to keep a "god". Evolution doesn't need a "god" to work and there are infinite possibilities of how the laws of physics could work.

          There is also the simple point that if the laws of physics worked a different way, we wouldn't be here to talk about them working the way they do, but because they work this way in this universe, we are here and have the option to create magical
    • by Lijemo ( 740145 ) on Thursday April 10, 2008 @09:07AM (#23023310)

      Considering approximately 5% of Physicists in the Unites States are religious I dont think they considered it a religous question.

      By "religious question", they mean, "according to our current understanding of the laws of physics, it is impossible, even in theory, to generate a falsifiable hypothosis about what happened before the big bang. Therefore, any discussion of what happened 'before' cannot be scientific, and hence is religions/philisophical discussion, not science".

      TFA is about some folks claiming "actually, we DO have a hypothosis that is, at least in theory, falifiable".

      "Science" is about studying things that are measurable, empirical, and/or falsifiable, whether one beleives that's ALL there is in the universe or not. "Religion" includes things that are not always empirical and falsifiable, and that cannot, even in theory, be scientifically tested. "Philosophy" includes all of the above and then some.

      Whether something is or is not science, and whether something is or is not real, are two seperate questions-- whether or not one feels both questions have the same answer.

  • It's just like history, really... History repeats itself, do does the Universe.
    • Exactly. I expect that if we could look into the moments immediately prior to the Big Bang, we'd see a bunch of scientists flipping a switch on the highest energy particle-accelerator of their universe.
  • by jollyreaper ( 513215 ) on Wednesday April 09, 2008 @09:43PM (#23019894)
    There were two universes but Manfred drones destroyed the Light Universe. Fortunately, we're already in the Dark Universe.
  • Galactus (Score:5, Funny)

    by dpilot ( 134227 ) on Wednesday April 09, 2008 @09:50PM (#23019930) Homepage Journal
    Marvel Comics has been telling us this for years! Decades, even!

    Galactus, the Overmind, and the Stranger all came from the previous Universe, by one mechanism or another surviving the Big Crunch and the following Big Bang. There may be other previous universe types, but those 3 are the only ones I picked up on, back in my comic book days. (decades ago, even)
    • Correction: Galan was the sole survivor of the previous universe, and was reborn Galactus. Death and Eternity are his "siblings", the similarly reformed instances of the former incarnations of life and death. Which is odd since he lives inside Eternity, and converts life into death to extend his own life... [] [] []

      • by dpilot ( 134227 )
        I bow to your superior knowledge of the Marvel Universe. Besides, my post was based on 30-40 year old memories. Did you ever stop to think that John McCain is the one Presidential candidate who can't make the "senior moment" joke over a memory lapse?
        • I apologize for any offensive if any was taken. My knowledge was based on 25 year old memories that have been continuously refreshed since I don't have a wife to throw out my comics or MSH role playing paraphernalia. ;-) ... :-/ ... :-(
          • by dpilot ( 134227 )
            No offense taken. I was just trying to make a Slashdot-ready phrasing for a response.

            I kind of drifted out of the Comics somewhere in high school, though I still have a few old ones laying around. (Including the "Batman vs Hulk" DC-Marvel crossover.) I also bought about a half-dozen Superman comics around the "Death of Superman" timeframe, just in case they gain collectors' value. Cheap investment, along with my 2 boxes of "Original Color" and 1 box of "New Wave" color Crayola 64-packs. (I bought the "
    • by elrous0 ( 869638 ) *
      The TV show "The Lexx" was posited on the idea of a light universe (abandoned by humanity) and dark universe coexisting. The "multiverse" is, after all, a VERY old sci-fi trope.
  • Physicist Theory? (Score:3, Insightful)

    by snl2587 ( 1177409 ) on Wednesday April 09, 2008 @09:52PM (#23019944)

    This may be similar with beliefs of Physicist Neil Turok of Cambridge University who has theorized about a cyclic universe, constantly expanding and compressing.

    Or Hindu belief...

    • Yup. They've been saying it for 3,000? 4,000? years. They left out most of the math, though, which made it too easy.
      • Depends on if you count the Harappans (~5500 B.C.E.) as Hindus, or maybe just the Classical Era populations (~1500 B.C.E.), or if you think it all starts with the Rig Veda (~1700 B.C.E.). It's tricky to say when what we call Hinduism today actually arose from earlier regional faiths.

        By the way, we're on the 5109th year of the Hindu calendar, but that's debatable due to local variations.
  • hurts my head (Score:5, Insightful)

    by INeededALogin ( 771371 ) on Wednesday April 09, 2008 @10:21PM (#23020094) Journal
    Adams said it best: "The Universe, as has been observed before, is an unsettlingly big place, a fact which for the sake of a quiet life most people tend to ignore."

  • by bcrowell ( 177657 ) on Wednesday April 09, 2008 @10:40PM (#23020192) Homepage

    There's nothing particularly special about loop quantum gravity that makes it possible to avoid having a singularity at the big bang. Loop quantum gravity is just one theory of quantum gravity. The best known theory of quantum gravity is string theory. In pretty much any theory of quantum gravity, the classical picture of the big bang singularity is going to get heavily modified. The conditions of the big bang are pretty much the only conditions under which you really need a theory of quantum gravity (unless you're really clever about finding some other situation, like black hole evaporation, where quantum gravitational effects come in). In all theories of quantum gravity, there's a scale called the Planck scale, and when you go beyond that scale (e.g., the universe is hot enough so that the wavelengths of particles are on the order of the Planck length), mysterious stuff happens. Because of this, it's reasonably plausible that the big bang singularity is eliminated in any theory of quantum gravity.

    Old attempts to make a theory of a rebounding big bang (with, e.g., a cyclic universe) had various technical problems, which have been solved in recent years. In a rebounding big bang, there are issues to worry about such as what happens to causality, entropy, and the thermodynamic arrow of time. E.g., you could imagine that a universe cycles through a series of big bangs, and that each cycle is a lot like the one before, or you could imagine that the second law of thermodynamics operates across rebounds, so that each cycle has more entropy than the one before. You could imagine that there could be cause and effect relationships extending across rebounds, or that that could be prevented by the laws of physics. Some people believe that there's an unsolved "entropy problem" in the current standard big bang theory. Here [] is a good FAQ about cyclic models.

    • by Anonymous Coward on Wednesday April 09, 2008 @11:53PM (#23020734)
      Disclaimer: I work on loop quantum gravity.

      Actually there IS something special about loop quantum cosmology - it's theory actively predicts a big bounce instead of a big bang. This comes directly out of the loop quantization of a homogenous and isotropic cosmology. So far all other theories have had to put in a bounce "by hand" - adding extra physics at the singularity in order to get something out of the other side. LQC doesn't do that - it replaces the usual metric and curvature operators with holonomies and flux operators as done in loop quantum gravity (OK, the derivation isn't exact yet, and we've a lot more work to do here).

      Once you do this, however (and by using other tricks like using a massless scalar field as your time variable), you see that a contracting branch naturally re-expands once you reach a critical matter density (something like 82% of the Planck density - Ashtekar has a good numerical reason for this IIRC). In these steps you end up replacing the Wheeler-deWitt equation (a continous differential equation) with a difference equation which needs to pick a certain super-selection sector of the theory - in simpler terms the timestep effectively becomes discrete.

      The beauty of LQC is that it doesn't need us to speculate about what happens at singularities - it gives us an active way to look at them without needing to invent new physics that only apply there. Sure, it makes a few assumptions - that our basic observables are holonomies and fluxes - but there's no new input directly at the singularity, unlike in other theories (such as ekpyrotic scenarios where two branches are joined artificially across the singularity.

      For an introduction, see Martin Bojowald's (one of the founders of LQC) living reviews site: []

      If you have questions, please reply and I'll see what I can do to answer them to the best of my ability. If there's enough interest, I might be able to get an "Ask Slashdot" type of thing put to Ashtekar/Bojowald although it'll probably be their post-docs and grad students who end up answering all the questions ;)
      • Hey physicists! Try holding still for a minute!

        While you guys go off on quantum loop tangents, we're still trying to work through some 19th century problems like the Riemann hypothesis! Your latest theories aren't scheduled to be made rigorous until 2158 at the earliest.

        Best regards,
        The mathematicians.

      • Disclaimer: I work on loop quantum gravity so you're not going to understand anything I'm about to say.

        I tried to follow along but I was lost somewhere around holonomies and flux operators, which I assume is related to the flux capacitor [].
    • by ceoyoyo ( 59147 )
      Incidentally, string theory ALSO predicts a kind of rebounding universe. IIRC it seems that in ST a universe with a radius of R is indistinguishable from a universe with a radius of 1/R, when measuring R in Plank lengths.
  • by ynotds ( 318243 ) on Wednesday April 09, 2008 @11:00PM (#23020340) Homepage Journal
    Though coming from very different directions, both LQG pioneer Lee Smolin [] and Stephen Wolfram [], who needs no introduction here, have opined that the best candidate as the fundamental level of a discrete physics (i.e. where the appearance of being continuous is emergent) is a graph theoretic network of nodes and links where it ceases to make sense to ask what they are made of. (This is also explored in Greg Egan's Schild's Ladder [] .) The basic idea is that there is some simple enough but cosmologically consistent transformation rule which produces the next local state of the graph from the current local state, supposedly at the Planck scale [] (of order 10^43 times per second).

    A likely scenario is that "somewhere" long unreachable beyond our event horizons, there was a region of network sustaining chaotic inflationary expansion in which a bubble of more conservative physics emerged. Our conservative bubble only exhibits polynomial (near cubic) growth but that was enough to separate it from the exponentially growing seed graph.

    My current betting is that Type 1a Supernovae [], or at least some more precise analogue thereof in our parent cosmos, seed new outbreaks of chaotic inflation in which a new generation of more conservative bubble cosmoses arise, the whole process being susceptible to selection for fecundity and constrained only by the need for a viable history to some initial conditions simple enough to have just happened, presumably for no better reason than because nothing is unstable.
    • The problem with such theories is twofold:

      First, we will likely never prove anything at the Planck scale. This means that without some radically better ideas, we may be stuck with current situation -- lots of theories but no proof.

      Second, one cannot take a theory that is wrong in a measurable way, make some small adjustment, and end up with a theory that is right. In field theory if we get the strength of electromagnetism wrong, we can adjust it. It's just a number. If we find a new particle we didn

  • by zerkshop ( 1222778 ) on Thursday April 10, 2008 @01:01AM (#23021080)
    Hmmm, the universe steming from the collapse of a previous universe.

    Read this off [] the other day. Kinda similar idea in ways:

    In David Brin's book "Earth" it is suggested by a scientist, that in the moment of the collapse of an experimentally created black hole, it separates itself from this universe (like the separation of a child from its mother) taking with it all consumed energy which lies behind the event horizon. In his speculation the implosion of a singularity in this universe is followed by an explosion/expansion of a singularity in the child-universe, which then became independent of ours. Of course this causes an energetic underpressure with every collapse of a black hole, finally making this universe disappear when the last singularity implodes. It can be interpreted as a variant of the oscillatory universe theory.

    What if the big bang was just the explosion of all the crap that was in the event horizon of a black hole from a parent universe?

    Questions I have are:
    -How could there be such a massive black hole in a parent universe that our universe originated from? Subsequent universes would have smaller and smaller total mass/energy so it couldn't go on forever, and that would mean there was a starting point?
    -Wtf is the collapsing of a black hole? I thought they evaporated...
  • Doesn't the geometry of the universe have to be closed in order for expansion to reverse and turn into a collapse?

    I remember that some calculations showed it to be either flat or almost so. Of course, the key could lie in the "almost"...
    • by jafiwam ( 310805 )
      Last time I followed this stuff. The universe was open (destined for heat death) and the margin of "how open" was HUGE.

      Unless the universes before had significantly different masses, there's no way this happened.

      It's irrelevant in any case. You can think, talk, have a beer while imagining all this stuff as much as you want. But unless you can tack a method of gathering data to TEST the theory it IS. NOT. SCIENCE.

      Fun, yes. Science? Hell no.

      Those Intelligent Design proponents are starting to reap the dama
      • This is the great danger that intelligent design poses to the U.S., according to Ken Miller. By trying to put the supernatural into science, it turns all of science into just another belief system, causing many to call evolution and global warming a "religion".
  • it's just like this one, except everyone wears cowboy hats [].
  • Of course. If there's a long series of 'big bangs' followed by 'big crunches' etc... Then it would just follow that there was a previous 'universe' that underwent a big bang/big crunch cycle, one before that, and probably one after ours crunches down then explodes again to creat another 'universe'.

    Yes, it will crunch down again because gravity always wins, even against Chuck Norris.
  • How exactly would this answer a religious question again? It still doesn't answer the question of where the Universe came from in the first place nor why it came about nor... I mean seriously, replacing a "We don't know" with the equivalent of "It's turtles all the way down" doesn't exactly answer any so called religious questions at all. In fact, it doesn't even encroach on them.

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