Physicists Calculate Number of Universes in the Multiverse

Discussion in 'Science and Technology' started by USS Excelsior, Oct 16, 2009.

  1. USS Excelsior

    USS Excelsior Commodore Commodore

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    Physicists Calculate Number of Universes in the Multiverse

    http://www.technologyreview.com/blog/arxiv/24239/

    If we live in a multiverse, it's reasonable to ask how many other distinguishable universes we may share it with. Now physicists have an answer:

    10^10^16


    One of the curious developments in cosmology in recent years has been the emergence of the multiverse as a mainstream idea. Instead of the Big Bang producing a single uniform universe, the latest thinking is that it produced many different universes that appear locally uniform.

    One question that then arises is how many universes are there. That may sound like the sort of quantity that is inherently unknowable but Andrei Linde and Vitaly Vanchurin at Stanford University in California have worked out an answer, of sorts.

    Their answer goes like this. The Big Bang was essentially a quantum process which generated quantum fluctuations in the state of the early universe. The universe then underwent a period of rapid growth called inflation during which these perturbations were "frozen", creating different initial classical conditions in different parts of the cosmos. Since each of these regions would have a different set of laws of low energy physics, they can be thought of as different universes.

    What Linde and Vanchurin have done is estimate how many different universes could have appeared as a result of this effect. Their answer is that this number must be proportional to the effect that caused the perturbations in the first place, a process called slow roll inflation, and in particular to the number "e-foldings" of slow roll inflation.

    Of course, the actual number depends critically on how you define the difference between universes.

    Linde and Vanchurin have applied some reasonable rules to calculate that the number of universes in the multiverse and have totted it up to at least 10^10^10^7. A "humungous" number is how they describe it, with no little understatement.

    How many of these could we actually see? What's interesting here is that the properties of the observer become an important factor because of a limit to the amount of information that can be contained within any given volume of space, a number known as the Bekenstein limit, and by the limits of the human brain.

    Linde and Vanchurin say that total amount of information that can be absorbed by one individual during a lifetime is about 10^16 bits. So a typical human brain can have 10^10^16 configurations and so could never disintguish more than that number of different universes.

    10^10^16 is a big number but it is dwarfed by the "humungous" 10^10^10^7.

    "We have found that the strongest limit on the number of different locally distinguishable geometries is determined mostly by our abilities to distinguish between different universes and to remember our results," say Linde and Vanchurin

    So the limit does not depend on the properties of the multiverse but on the properties of the observer.

    How profound is that!
     
    Last edited by a moderator: Oct 17, 2009
  2. Balthier the Great

    Balthier the Great Fleet Captain Fleet Captain

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    Why does it depend on US? Things exist or don't exist on their own merits especially things that happened before the earth was formed.

    Actually, If I understand the equation correctly, the answer is actually that there are NO universes. After all there could be no "observers" in a universe that doesn't exist yet.

    N(observer) ~ 10^10^16
    N(0) ~ 10^10^16

    0 ~ 10^10^16

    So what am I living in ...:confused:
     
    Last edited by a moderator: Oct 17, 2009
  3. Alpha_Geek

    Alpha_Geek Commodore Commodore

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    ...and add one more for the 'verse that didn't come up with the formula! :bolian:
     
  4. Jadzia

    Jadzia on holiday Premium Member

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    Existence / non existence is the most fundamental but least understood concept. Especially as we're considering that mind is somehow implicated with it; we do not understand mind either.
     
  5. JustAFriend

    JustAFriend Commodore Commodore

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    No one reads Heinlein anymore???

    The answer in "The Number of the Beast" was 10^6^6^6....
     
  6. Squiggy

    Squiggy FrozenToad Admiral

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    Heh.

    "Nob server".
     
  7. CaptainPipcard

    CaptainPipcard Lieutenant Red Shirt

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    If there are other universes, there should be an infinite number of them.
     
  8. PurpleBuddha

    PurpleBuddha Rear Admiral Rear Admiral

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  9. Jadzia

    Jadzia on holiday Premium Member

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    USS Excelsior, we would prefer it if you provide some original content beyond copy'n'pasting somebody's blog entry.

    Also, don't forget the rule about hotlinked images. :)
     
  10. Zachary Smith

    Zachary Smith Vice Admiral Admiral

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    Perhaps "Time" is a phenomenon based on the function of the observer ("us") slipping from one universe to another in progression going from highest energy at the onset (the Big Bang) and descending through each "lower energy" universe until it reaches the lowest energy universe of entropy. Locally, the energy levels may rise or fall dependent on environmental conditions but we, the observers, SLIP along a gradient from higher TOTAL energy universes to lower energy ones, thus we "see" progression but the progress is an illusion as each universe is STATIC and unchanging.

    Think of a movie--each FRAME of the film being a "universe" which is static but every subsequent static frame is subtly different, thus creating the illusion of "progression" where NONE actually occurs.

    THUS, the TRUE nature of "time" is unveiled.

    You're welcome.

    Now, I'll be in the lab the rest of the day, working on my time machine . . . .
     
  11. Lindley

    Lindley Moderator with a Soul Premium Member

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    This is one of those projects which is briefly curious but probably useless from a practical standpoint.
     
  12. Shaw

    Shaw Commodore Commodore

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    I don't know about that. I think this type of research might prove helpful to those endeavoring to answer the age old question...

    How many angels can dance on the head of a pin?

    Personally, I think everyone involved in this "Multiverse" stuff is having issues with standard definitions. The universe is everything. Hence when you find something, it is by definition part of the universe.

    No matter where you go, there you are. :techman:
     
  13. Ronald Held

    Ronald Held Vice Admiral Admiral

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    Typing this on my phone.
    There are many estimates of how many causal separaate regions there are. All are just estimates.
     
  14. Zulu Romeo

    Zulu Romeo World Famous Starship Captain Admiral

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    I find it comforting somehow that someone has dared to define the limits of our seemingly limitless imaginations. Odd, I know, but somewhat comforting. :)
    [LEFT]42. :bolian:
    [/LEFT]
     
  15. Verteron

    Verteron Lux in tenebris lucet Premium Member

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    That's a big, meaningless number.

    I think it's also safe to assume that whatever comes next in our line of evolution (whether it be supermen or artificial intelligence or reptolizards) they'll probably have bigger brains than us. More to the point though is that the universe only contains about 10^100 atoms at most, which is smaller than this number, so even if you assembled the entire universe in to an enourmous memory chip (and where's the fun in that?) you still couldn't record all the interesting details about all these universes.