The True Science of Parallel Universes

Everyone loves the idea of parallel universes
– maybe it’s the appeal of an ideal world where you have second chances and things turn
out differently – an alternate reality where you do get into Hogwarts and the Star Wars
prequels aren’t made and you finally plug in your asymmetric computer cord correctly
on the first try… but is there really a place in science for such wistful speculation? I mean, if “the universe” is everything that
there is, you can’t have two versions of it, right? Otherwise the pair would really be
everything and what you started off calling the universe, wasn’t. The problem here is terminology: physicists
speaking informally often say “universe” when they really mean “observable universe” – that
is, the part of the whole universe that we’ve so far been able to see. And it’s perfectly
fine to talk about multiple different observable universes – for example, an alien near the
edge of OUR observable universe will see parts of the Whole Universe that we cannot yet see,
but that’s a well-understood question and not what physicists normally talk about when
they discuss multiple observable universes, or “multi-verses.” So let’s cut to the chase: in physics, the
word “Multiverse” normally refers to one of three distinct and largely unrelated proposed
physical models for the universe – none of which has been tested or confirmed by experiment,
by the way. The three “multiverse” models are: Type 1) Bubble universes or baby black hole
universes. This is the most straightforward kind of multiverse: the basic idea is that
perhaps there are other parts of the universe which are so far away that we will never see
them (or are inside black holes so similarly we will never see them).
This kind of model was created as an attempt to explain why our universe is so good at
making stars and galaxies and black holes and life – as the argument goes, if each of
these separate mutually un-seeable “bubbles” in the universe had slightly different laws
of physics, then by definition we could only exist in one that had the right physical laws
to allow us to exist. If you’re not convinced by this logic, don’t worry too much: there’s
not yet any experimental evidence for this kind of multiverse.
Multiverse type 2) Membranes and extra dimensions. Inspired in part by the inability of the mathematics
of string theory to predict the right number of dimensions for the universe in which we
live, string theorists proposed the idea that perhaps what we think of as our universe is
actually just a three-dimensional surface embedded within a larger super-universe with
9 spatial dimensions. Kind of like how each page of a newspaper is its own two-dimensional
surface embedded within our three-dimensional world.
And of course, if space had 9 dimensions rather than three, there’d be plenty of space for
other three-dimensional surfaces that appeared, like ours, to be universes in their own right,
but, like the pages of a newspaper, were actually part of a bigger whole. These kinds of surfaces
are called “membranes” or “branes” for short. And as a reminder, there is not yet any experimental
evidence for this kind of multiverse. Multiverse type 3) The many-worlds picture
of quantum mechanics. Surprisingly, physicists still don’t fully understand how the collapse
of the wavefunction in quantum mechanics happens, and the many-worlds hypothesis makes an attempt
at explanation by proposing that every possible alternate timeline for the universe is real
and they all happen in an ever-larger, ever-branching way. Like, a universal choose-your-own-adventure
where every possible story happens! If this were the case, we might not realize
it because we’d be stuck living out just one of the infinitely many possible lives available
to us. In some ways, many-worlds is similar to the bubble multiverse model by proposing
“maybe anything that can happen, does. And we just happen to exist in the series of happenings
that were necessary for us to exist.” If you’re still not convinced by this logic, don’t worry:
there is not yet any experimental evidence for this kind of multiverse. Of course if you want to get imaginative,
you could also combine several of these models together into a multi-multiverse… a new
super-speculative model based, itself, on speculative and experimentally unconfirmed
models. But that’s not to say we couldn’t test these
multiverse hypotheses. For example, if our observable universe were really just one of
many disconnected bubbles or membranes and if it happened to collide with another bubble
or membrane some time in the past, then that collision would certainly have had some sort
of effect on what we see when we look up at the night sky.
On the other hand, the many-worlds interpretation might be tested fairly soon since experimentalists
are becoming increasingly able to manipulate and control ever-larger quantum mechanical
systems in their labs – systems that approach the line between the quantum realm and our
everyday experience. So as always, we must remember that physics
is science, not philosophy; and in our attempts to explain the universe that we observe, we
have to make claims that can in principle be tested – and then test them!

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33 Responses

  1. Mukul Shukla says:

    I watch your video same time I don't watch your video in other universe it's ???lol

  2. Crabs says:

    0:10 Why would i want to go to hell

  3. Nghĩa Trương says:

    Git checkout

  4. Waw Majikk says:

    in another universe, pewdiepie Focused on his school and never did youtube

  5. Sub 2 Pewdiepie says:

    You mean Soviet Russia?

  6. Igivecrab rave says:

    So we are all same right?

  7. Sc4ry Dude says:

    I have check every universe, in every universe I don't have money

  8. Lord Odysseus says:

    I have been saying this for YEARS!

  9. The Anonymous Painter says:

    Im afraid that a single drop of ballpen will make me not graduate in highschool

  10. Daddy took the vacuum back downstairs says:

    I didnt write this comment in an alternate universe

  11. Axeque. says:

    i feel like parallel dimensions are all around us, just interwoven into reality so that we cant actually see nor interact with them. we'd need to shift our dimensional perspective somehow to access it, which would look incredibly cool. sort of like an acid trip.

  12. Ella R says:

    In another universe you might not exist ?

  13. Wanda Maximoff says:

    It's so crazy how in another universe, I could be the opposite gender or have blue eyes or my pet that died is alive

  14. Kitty Cheshire says:

    In another universe, main characters in horror films are not dumb.

  15. Haji Hussein says:

    Hop thats real at least i will be with ma lover in another universe

  16. TopicEverything says:

    What if only your soul can travel to different multi-verse

  17. A. - says:

    this is not the way how to present information to other people.

  18. A. - says:

    playing speel 0.75… otherwise normal people become crazy of your voice.

  19. Dj Exo says:

    I used to really believe in all this but it gets hard of course you can do what you want and change your future or the future but it’s just life and just do what you want I guess

  20. Ari that awkward girl says:

    I understood close to none of that

  21. Sujit Pachode says:

    Who watched this video in 2019

  22. Cheeseburger Monkey says:

    In some parralel universes you have wrote, are writing, and going to write this comment right now!…and in the past and future 😉
    And you wouldnt have edited this comment
    and not have wrote this
    and wouldve wrote all of this in the future
    and not have done this and edited
    OK ok ill stop (but you wouldnt have doen this XD)
    and have wrote this in other dimension hjdddjejnexsnd
    ok now for real ill stop
    and all of these comments wouldnt have existed


    The Pillai Theory
    Every single electron, neutron, proton are made up of zillions of universes

    Uhhh, it's my own theory btw

  24. Tore Kesicki says:

    Does it matter if something works or not if it works for you if it's considered a Pseudo-Science? I got a nasty email the other day regarding how the world has gone to hell because people are always coming up with a new thing to make money. This prompted me to look up the definition of a Pseudo-Science which is “a collection of beliefs or practices mistakenly regarded as being based on the scientific method.” I was shocked to find out that the majority of the tools that people use today to feel better about themselves fall under this category. Check this fraction of the list of Pseudo-Sciences… Astrology, Homeopathy, Reiki, Meditation, Visualization, Numerology, Psychoanalysis, Hypnosis, Chiropractic. My point here if it works it works. Keep up the great work. Tore Roberts

  25. Daryant Al-Solomon says:

    You need same frequency to go to multiverse, they run on their own different frequencies

  26. Homo Erectus says:

    Türkçe alt yazıyı yapanın kendi dilini bildiğinden kuşkuluyum

  27. Andrew Marinelly says:

    I always thought the double slit experiment is proof of theories 2 and 3. If you just assume that the wave function of atoms comes about because it is multidimensional and time being one of those dimensions it could appear to act as a wave because it can be everywhere it could possibly be at any given time making it act as a wave. When you add observance to the atom it can no longer function that way as it is now displayed on "our" brane and time can only be displayed as normal entropy.

  28. Regi Widiantoro says:

    I gonna die without know anything

  29. Filipa Gomes says:

    my last 2 brain cells just died

  30. BoxWolf 18 says:

    Smart me : watches Doctor Strange

  31. Mellow & WeeeGe Offcial says:

    If their even is a opposite dimension it wouldn't exist because considering that fact hat we exist the opposite of that is nothing! Nothing won't exist there

  32. NoahStorys says:

    Ok, now explain an omniverse, please

  33. Ben Baxter says:

    infinite crisis

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