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Multiuniverses speculation

  1. Mar 30, 2003 #1
    I read and heard from a professor about the speculation (simply speculation) of multiuniverses (in otherwords, there is more than the one Universe we reside in).

    According to Quantum Mechanics, there are quantum fluctuations which, as some scientists theorize, may have created the Universe. If one QF created this Universe with it's specific set of laws, then what prohibits another QF creating a "Universe" and then another QF created another "Universe" so we have many universes, each with a different set of laws governing it?

    The only problem is that one couldn't virtually detect these other universes unless, as some scientist assume could be a possible way, is for the the universe to "leak" into the one we reside in.

    I found this quite interesting. Any comments?
    Last edited by a moderator: Feb 4, 2013
  2. jcsd
  3. Mar 30, 2003 #2


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    It is very possible that there are other universes we will never be able to interact with. Of course, this is speculation. So assuming there were in fact other quantum fluctuations which gave rise to other universes, would their laws be like ours?

    Unlikely, in my opinion. Our universe consists of the four fundamental forces: strong, weak, electromagnetic and gravitational. The first three, and possibly the fourth too, appear to be manifestions of a single force when energy levels are greater. Due to the process of sponteneous symmetry breaking, the forces have split apart at lower energies. Apparently, the point at which these forces split are free parameters and could take on other values in other universes. In those universes, the types of particles might be different, the periodic table might look different, and life might not be an option. Potentially, even constants like h and c might take on different values.

    And wondering even further... could a quantum fluctuation occur within our universe which would one day blow away its contents? If it were an even bigger fluctuation?
  4. Apr 2, 2003 #3
    Re: Multiuniverses

    Something I found for you Sting.

    From: Chris (Avatar) 30/09/99 17:19:50
    Subject: re: Multiuniverse & Quantum post id: 41482

    It's not so much a theory as an explanation.

    The quantum theory is weird. Very weird. To a classically trained mind (like all minds originally are) it just doesn't make sense: you don't know where things are unless you don't know how fast they're going; things can appear and disappear with no energy cost; you don't know something exists until you look at it and then it appears as you were expecting it to - but if you expected it to look different it would look different; etc etc.

    Classical thinking doesn't work for quantum tunnelling or quantum teleportation or entanglement, for uncertainty, for wave/particle duality or for collapsing probability wavefunctions. You kind of have to develop a whole new "quantum common sense".

    One of the tenets of the theory is that observation plays a big role in determining reality (see the links below for more detail). You may have heard of Schroedinger's famous cat experiment:

    Schroedinger was one of the guys who helped put together the mechanics of the quantum theory, including the probability wave function. But he was distressed at the way the theory "didn't agree with common sense" and tried to show this with a thought experiment. In it, you take a cat and put it in a box. In the box is a vial of poison and a single uranium atom. The experiment is set up so that if the uranium atom decay's it will break the poison vial, release the poison and kill the cat.

    OK. Now you seal the box. The decay of a single atom is a quantum event - until you observe it, it isn't resolved. This means that at one and the same time, the atom has both decayed and not decayed, that the probability that it has decayed and not decayed are superimposed on each other. (Note - this is weird quantum behaviour. Your mind will try to tell you that only one of these is real - you just don't which it is because you haven't opened the box. But this is your normal common sense talking, and it is wrong !! The cat is both alive and dead at the same time).

    So the cat exists in this weird state where its live probability waveform and its dead waveform are superimposed. (Remember - this isn't some weird hippy philosophical interpretation of not seeing in the box, it is the actual physics of the situation!) Then... you open the box! Instantly one of these two waveforms collapses and the other resolves into "reality". Importantly, your observation of the system precipitated the waveform collapse - you're not merely an observer anymore.

    Now as I said - this is weird. There are several ways of explaining such a thing to a classically trained mind so that you can make sense of it. One of these is the "many universes" interpretation (not a favourite of mine - or Dr Ed's for that matter). In this interpretation we imagine that the universe split in two when you open the box. In one universe the cat lives and in the other it dies. Each universe is otherwise a carbon copy, and neither can interact with the other ever again.

    Keep in mind that this is an interpretation, a way of explaining quantum weirdness. There isn't an experiment we could perform which would detect these innumerable "splitting universes".

    You can get more information on the many universes theory here, (missing link)

    and I'd definitely recommend Dr Ed's rather elegant explanation of the wave/particle nature of light here. (missing link)

    Hope this helps!
  5. Apr 3, 2003 #4
    if the big bang was a local random event

    our univerce in is a bubble limited by the time it has expanded to present size [+or- 13 billion years]

    if other random events have happened in other places OUTSIDE our bubble, and there are other big bangs creating their own univerces OUTSIDE OURS.

    if our univerces observed accellerations of the expansions rates are caused NOT BY NEW FORCES, but by the gravity of the outside univerces pulling our stuff outward, then we have a simple explaination of the cause of the accelleration and proof of stuff outside our univerce!!!!!

    and our place/space just got way bigger tooo!!!!
    without extra "D" or other wierd stuff
    and only useing current laws
  6. Apr 3, 2003 #5
    Constants may be the most basic physical measure in any universe, so expect other universes to differ in these parameters, both in value and dimensionality. Separate universes could also distinguish conserved quantities, as they might the relation between physical mathematics and observed physics in general. Even fundamental concepts like wave/particle duality and spatial curvature might not exist outside our cosmos.
  7. Apr 4, 2003 #6
    Re: Multiuniverses

    I wonder what kind of mental picture you have about "other universes".

    One, simple, model is just to portray the current observable universe, as something like a "universe island" (a galaxy previously was called an island universe) which reside next to other "universe islands" in the same space/time, so they can be in principal causally connected.

    In this model, you just extrapolate from the know structure of the universe (galaxy, local group, cluster, super cluster) to an even bigger structure. In theory there exists interaction between these "island universes".

    I would not call these universes not seperate universes, but part of our own, but just very far away parts of the universe.

    Another and totally different picture is to treat the universe as a seperate spacetime bubble. So other universes are in their own spacetime. Each spacetimebubble can grow, but remains a seperate spacetime bubble, never touching another spacetime bubble. The seperate spacetime bubbles are not seperated by spacetime themselves. This means that even in theory there can be no interaction between seperate universes.

    This category of "existence" is however very doubtfull, because it is even in theory impossible to detect their existence.
    We can only indirectly assume their existence, from theoretical reasons, cause they would be caused by the same process as our universe.

    This remembers me about something else. Suppose we theoretically define a new kind of matter, consisting of particles and energy and fields or other material forms. This kind of matter could interact with itself in a similar or different way as normal matter. Only, this new kind of matter does not interact at all with normal matter. Not by the force of gravity, or electromagnetism, or weak or strong nuclear force. It would even be possible for this new kind of matter to occupy the same space as normal matter (else of course, there would be interaction). In other words, it would be in theory totally impossible to detect this new kind of matter.

    Would this new kind of matter exist? What kind of existence would that be?

    In brief, I would be very suspicious about a category of existence, which is even for theoretical reasons impossible to verify. To say that something exists, must distinguish it from something that does not exist, if this distinction can not be made, it would be wiser to not state it is existent.

    In the case of the island universes, I would not call that seperate universes (for the same reason we do not call another galaxy to be another universe, as was previously thought) but just part of our own, but just far outside our present observed spacetime, but still residing in the same spacetime bubble.

    Just one universe is enough.
    Last edited: Apr 4, 2003
  8. Apr 5, 2003 #7
    Thanks for the info QuantumCarl :smile:

    To be honest, I couldn't imagine it. THe way of thinking that has been ingrained into me since 3rd grade is that the Universe is EVERYTHING.

    A few nights after posting this thread, I was lying on my bed in my room with the lights off and The Doors playing on the stereo in a low volume. I was taking a break from studying for my upcoming Chemistry test, when I had a thought about what "multiuniverses" would look like in my surreal imagination (remember, I was listening to The Doors).

    I pictured (as Huesdens mentioned) as bubbles or 4 dimensional "cells". If you took some liquid dishwashing soap, added water and stirred it till it produced a lot of bubbles, that was basically the image of "multiuniverses" that came to mind at that moment. In this froth of bubbles, where one membrane of a bubble ends, another bubble begins.

    Of course, I'm not a crackpot by nature. This was simply how I imagined it to be. Right or wrong is not the issue. This was just my imagination at work.

    My only question concerning multiuniverses: If multiuniverses did exist, then what do you call a group of multiuniverses?

    I agree. We have a lot of unanswered questions about this universe we live in and there are more?
  9. Apr 5, 2003 #8
    The concept of multiversums is also used in eternal inflation theory, the universes with potentially different sets of natural laws are seperated by so-called domain-walls.
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