Podcast: Multiverses

What if our universe was just one in an infinite number of parallel universes; a possible outcome from the specific predictions of quantum mechanics. The idea of multiple universes is common in science fiction, but is there any actual science to back this theory up?

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Multiverses show notes and transcript.

11 Replies to “Podcast: Multiverses”

  1. Thank you for this podcast! You are opening the ‘doors of perception’ which further enables consciousness in THIS universe, which might then expand exponentially into scientific reality!!

  2. Aqua, I have no idea what you are talking about.
    There is no relationship between a consciousness and multiverse. Only pseudo scientists would invent such a thing.

    The multiverse thing is not proven yet, and if it exists there are numerous models about it but no one knows if any one of those is correct. At this moment these are just numbers and some formulas that needs to be checked with reality. The LHC might give a glimps of a possible multiverse. But right now keep your feet on the ground. Your eleventh dimension might be about 0.1 mm big at its maximum so it is only important at atomic level or even smaller.

  3. The three alternatives listed in the podcast are:
    1) The laws of the universe have been decreed by some sort of deity, and that’s where science meets an insurmountable roadblock.
    2) The apparent fine-tuning of our physical laws are the only possible result of deeper principles, just like the number Pi can’t have any value than what it does.
    3) There’s a gajillion universes with all sorts of different rules existing alongside ours, so we should not be surprised to find there’s some universes in that multitude that appear to be fine-tuned.

    I don’t like any of these alternatives. 1 and 3 seem very similar to me in that, if you’re going to invoke a bunch of parallel universes that can’t be observed just to explain the one that can, you might as well postulate a God of some sort and have done with it. #2 is also unsatisfying, because if our physical laws arise inevitably from deeper underlying laws the question arises, “why THOSE deeper principles?” I suspect that, sooner or later, science will reach a limit to what can be investigated and explained, and we’ll just be able to say “That’s just the way it is.”

  4. Olaf – My suggestion is that the visualization of the concepts put forward in this podcast will act to introduce, even stimulate further thinking along the same lines – thereby promoting, even encouraging continuing experiments.

    Is that so difficult to understand?

  5. I think that the cosmological constant, a pillar of the fine tuning issue, is determined according to some quantum critical point. Here quantum fluctuations of a time &t (& = delta) is proportional to hbar/&E. This time in a Euclidean setting is equivalent to a temperature with E = kT. So the random fluctuations on a quantum level determine the ordering of a system in much the same way a temperature determines the phase of a system. This renormalizes the cosmological constant /\ ~ 1/L_p^4 ~ 10^{120} to a much smaller value. So in a multiverse setting most cosmologies (universes) might then have small cosmological constants and be tuned approximate to what we see in our spacetime, cosmology or universe.

    There are some questions with the whole multiverse theory. One of them which I find particularly troublesome is how it is that all these other universes or cosmologies have real content as classical structures. It is not hard to see how these might exist as tiny quantum amplitudes or fluctuations about the universe we observe. Yet that requires the fine tuning to be highly singular, which is hard to arrange even with a possible tuning mechanism I suggest above. Yet if these other cosmologies have classical or ontological existence then it is hard to understand how two or more quantum outcomes can obtain at the same time. Quantum holography might provide an answer to this, for it does indicate how different quantum descriptions of a string interacting with a black hole can exist.

    It has to be realized that there are more questions than answers here, which is what makes this subject interesting.


  6. It is entirely possible that left brained linear thinking will not allow the concept of multiverse theory to exist. The bicameral nature of our minds, at this stage in our evolution, tends to prohibit the concept of ‘cosmic’ or whole mind consciousness. Again.. that does not mean it doesn’t exist!

  7. @Aqua, ok lets assume that galaxies are the neurons of the universe. It will have no clue that people existed.

    Unless you are aware that right now in your brains a few million of neurons are worshipping you as a god?

    It gets worse, the signals to travel from galaxy to galaxy would take million of years. The cosmological brain would probably take a few million years to have a human one second of thought. Human existence would have existed for only a blink of the universe his eye.

    I am sorry, but the cosmic consciousness is maybe good for therapy but is really pseudo-science.

    Multiverses are actually pretty boring if they exist.and is only at quantum level.

  8. Cosmology and/or Physics meets philosophy! This is typically a fascination for almost all scientists who study these items.

    Olaf… since we know there is at least in small detail, the reality of Quantum Entanglement (ala quantum teleportation)… never assume one body doesn’t communicate with another body at extreme distances…… at extreme rates.
    …and I cannot see how multiverses could be boring.. since there is a virtual endless combination of things which could happen in them. There could be a universe where the “Force” described in Star Wars, and how it is used is a reality.

    There could even be a universe where LB Crowell makes sense.

    Since we know there was likely some form of quantum chaos after the bing bang(s), why couldn’t there be different universes… all with different or unique physical laws, forces, etc? Who says the same little bits and pieces which form the atoms in our universe are the only way an atom can be formed?

    Nexus…what other alternatives are there? All universes are either 1-created by a diety, 2-Relatively the same as ours, 3-Different from ours. Although I agree the first one could be attached to either the second or third.

    A recently published book, which has consolidated some of the thoughts of quite a few scientists and philosophers, as well as goes into some pretty kewl ideas is:
    Universe or Multiverse by Bernard Carr; Published by Cambridge University Press

    You never know… as fast as we find new things, we bring up many more questions. Today this is philosophy… tomorrow, evidence begins to be collected… The next day, we are beginning to seriously debate instead of wonder.

  9. A rather decent podcast actually, often the subject tempts too much generalization.

    Speaking of which:

    “these are just numbers and some formulas”, “Cosmology and/or Physics meets philosophy”.

    Um, no. There are several multiverse bona fide theories, as podcast listeners could hear about. That one can make definitions and provide predictions elevate the subject beyond philosophy and math.

    @ Nexus:

    I don’t like any of these alternatives.

    Agreed. Neither do most anthropic researchers AFAIU, the weak anthropic hypothesis is the most popular. I.e. there is here as everywhere else a distribution over parameters, which makes some parameter regions more likely. Often this hypothesis meets with predictive success, see Susskind and Tegmark et al papers.

    1 and 3 seem very similar to me

    They don’t seem similar to me at all. The first one is an unnatural hypothesis, the third one is a natural one. More precisely, the idea of a parameter space that results in multiverses is AFAIU exactly equivalent to have a bias in a field theory like EM. This invokes a bunch of parallel solutions that can’t be observed just to explain the one that can.

    There is, of course, numerous other situations where an invocation of parallel objects that can’t be observed is done in physics just to explain the ones that can, for example infinite dimensional Hilbert spaces or particles and virtual particles in QFT, and so on and so forth.

  10. Torbjorn Larsson ….

    This isn’t my first trip around the multiverse block.

    We have been describing these theories as, “cosmology meets philosophy” for quite some time; it is a common phrase.

    I wouldn’t say there are any “bona-fide” theories. However, I wouldn’t throw away evidence brought to life. Such evidence only hints to a multiverse in general… nothing to a specific theory.

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