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String Theory- Multiverse

  1. Feb 28, 2015 #1
    Well, the string theory talks about multiverse, unlike the Big Bang theory.

    Michio Kaku explains it by comparing it with bubbles.
    There are many universes. These universes are like bubbles floating around, and when they collide, they form a single bubble- a universe. When a single bubble, universe, separates, it forms two universes.

    My questions is- What is in between these universes? What is the beginning of these universes? Does that question ask for another big bang? The multiverse big bang?

    And plus, in the big bang theory too, what's outside the expanding universe? I assume it's dark matter. But how did that come into existence?

    Bottom line: None of these theories talk about the beginning of everything. Do you have any ideas?
  2. jcsd
  3. Mar 1, 2015 #2

    Suraj M

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    Are you sure?
    Putting it in a simple way, before the big bang, singularity! there's a theory which says that time goes slow at the centre of this singularity, the density is said to be tending to infinity, that means that there was no time before the big bang, as the universe expanded, time was born/created... so you can't refer to anything before the big bang. as there was no time
    I might be wrong, i just saw this in some documentary with Stephen hawking.Browse through this
  4. Mar 1, 2015 #3
    Well, we can't be sure about anything here.
    Last edited: Mar 1, 2015
  5. Mar 1, 2015 #4


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    Kaku was once a respected physicist but is now a popularizer of the worse sort and his name should be spelled Kaka.

    Since this is all pure speculation with no known basis in reality, you can pretty much put in whatever answer you like
    there isn't anything "outside". There IS no "outside"
    It's turtles all the way down. That's as good an answer as anyone has come up with so far.
    Last edited: Mar 1, 2015
  6. Mar 1, 2015 #5
    From this blog post- M-Theory Repositions: Now You Can Thank Us For Quantum Mechanics Too, my favorite quote concerning Kaku-

    "The safe bet remains that if Michio Kaku embraces it, it is okay to disregard it."
  7. Mar 1, 2015 #6


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  8. Mar 1, 2015 #7


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    The idea of many universes I think concerns whether there are more than 1 vacuum states in which the universe can exist. If that is the case, there is nothing inbetween , just empty spacetime, and the two universes expand (their horizons expand) until they collide (at that time you'll get a domain wall inbetween them, and probably a catastrophic thing could happen). That's where the bubbles come in (discriminating different vacua).

    I agree on the comments about Kaku.
  9. Mar 5, 2015 #8


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    Cut Dr. Kaku some slack. If you are not immersed in academia, there aren't a whole lot of other ways for a scientist to earn a buck outside of entertainment. Kaku thrives on off the wall topics, because that's what sells. I think popularization is good for science. It piques public interest, albeit sometimes misguided, which motivates public funding for science. That, in turn, enables a tech driven society and prosperity.
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