How Many Universes Are There?

  • Published on Sep 30, 2019
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    The universe is big, but it’s peanuts compared to the eternally inflating multiverse. But just how many universes are there? What are they like? And most importantly, what can they tell us about … aliens?
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    Hosted by Matt O'Dowd
    Written by Matt O'Dowd
    Graphics by Leonardo Scholzer
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    Imagine it: the observable part of our universe is 93 billion light years across, and that’s just a small fraction of the stuff created in our Big Bang. But in the eternal inflation picture, ours is just one among uncountable bubble universes. Bubbles that are continuously appearing and growing within a vastly larger spacetime that itself expands at an exponentially accelerating rate. A greater inflationary spacetime whose expansion never ends. We looked at the bizarre idea of eternal inflation in recent episodes - but we stopped short of exploring the full implications of this proposition. Those implications are, frankly, completely nuts. Some may also be true.
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Comments • 3 246

  • Eugenio Ricca
    Eugenio Ricca 18 hours ago

    To me the claim thet our observable universe is 93 billion light years across doesn't fully make sense. We calculate this figure taking in to account the accelerating expansion.
    So we say that le furthest object we observe now as it was 13 billlion years ago is now 46,5 billion light years away. problem is we are observing it as it was 13 billion light years away so our observable universe is still 13nish billions light years away no matter what. The notion of an accelerating expanding observable universe informs us that the furthest object that we can observe is emitting now light that will reach us in around 33 billion years. Am I wrong in saying this? Anyone?

  • David Hand
    David Hand 3 days ago

    I don't like this angle for the Fermi paradox. There's no reason to believe that we are at second one in our universe and there's no reason to believe anything at all about other (bubbles of) universes. There's an awful lot of a priori going on here.

  • KasaTheDog
    KasaTheDog 6 days ago

    I was trying to see if I could get this shirt bcs its looking so cool but I cant find it :c hope its just sold out and not lost to the invinite universe forever!

  • Van Boyette
    Van Boyette 7 days ago

    The vacuum universe seems to be a dead end. Essentially a black hole creates and enables the vacuum space. What happens when the vacuum spaces become filled? Then can the oceans that fill them be navigated?

  • Barry Deeks
    Barry Deeks 8 days ago

    There are no alternate universes, and next year I shall explain to the greatest minds in the World, I should know it's my creation.

  • Nehmo Sergheyev
    Nehmo Sergheyev 9 days ago

    Would you let someone talking about this stuff fold your parachute?

  • UserName0043
    UserName0043 9 days ago

    Space is gay

  • John Smith
    John Smith 9 days ago


  • Minkyy
    Minkyy 10 days ago

    If u think we’re the only ones in this huge ass... universe? Multiverse?
    You’re dead wrong. I hope I’m still alive when we discover aliens (hopefully friendly aliens)

  • Colin Lynas
    Colin Lynas 10 days ago

    If 2 or more universes collide, how would the laws of physics effect the new combined universe? Does it effect the whole combined universe immediately or does the potential change permeate from the point of contact. Do the physics of the combination cause the process of combination to happen instantly outside time. What if one of the universes didn't have a time dimension or the effect of gravity was weaker? What would this even look like to the objects or occupants in those universes! It is a very interesting mind-boggle.

  • Kamugin1
    Kamugin1 12 days ago

    Astrophysicists should cut down their consumption of marijuana and LSD.

  • Jan van der Gaag
    Jan van der Gaag 13 days ago

    Just wondering about the laws and constants of Nature being different in each Bubble Universe. Could the speed of light ( c ) be really huge, like 10^(10^(10^(10^10))) m/s?
    Consider that this is the speed at which the size of the bubble grows. That would mean that after inflation stopped such a bubble would instantly be expanding FASTER than inflation! It would be gobbling up the inflating universe around it, colliding into and overwhelming many many other Bubble Universes.
    Maybe we are just a second away fro

  • michael mcclatchy
    michael mcclatchy 14 days ago

    The question is, What happens when they collide? I understand the theory that universes infinitely create in space time, but it sounds as if there’s constant collisions between universes. What happens when that occurs, other than the creation of new universes, because in our own universe, just for a reference. When black holes collide there’s an incredible amount of energy released. So, in space time, the collision of universes simply leads to a never ending creation of further universes? I feel there could be more, and the video briefly touched on it when they talk about dark energy

  • David Sims
    David Sims 17 days ago

    Can you use tetration instead of exponentiation in order to keep track of the number of bubble universes in the multiverse, as a function of time? I haven't yet seen a practical application for tetration, but if there is one then this surely must be it.

  • Felipe Do Rosario
    Felipe Do Rosario 20 days ago

    What happened to the real physics that used to be taught in this channel...

  • Fernando Lehue
    Fernando Lehue 22 days ago

    why does he say that when the potential energy goes from one minimum to another the exponential expansion stops, shouldn't it just reset (after a transition period) and expand exponentially with just a lower constant?

    • Fernando Lehue
      Fernando Lehue 22 days ago

      well that's what we see in our expanding observable universe :P

  • Edwin Bz
    Edwin Bz 23 days ago

    There is a universe where I'm literally balls deep in Matt's gf while we both watch this video 😂😂

  • Scott
    Scott 23 days ago

    10 to the 10 to the 30 to the wtfff I should have paid attention in school

  • MrWearenotallequal
    MrWearenotallequal 23 days ago

    A lot of assumptions there.
    Could be way out.

  • Mike Clancy
    Mike Clancy 23 days ago +1

    Cosmologists over 35 who have been drinking too much have been driven to this untestable metaphysical gobbledygook. Let's stick to real physics.

  • Mike McCormick
    Mike McCormick 23 days ago

    More comic book Star Trek fantasy and junk science. Maybe maybe not. Don’t lecture like it’s fact. Theory only.

  • Mark Bivins
    Mark Bivins 24 days ago

    After discovering entropy is one way they get all nihilistic and figure what's the use in exploring the universe if it's all going to end some day and there's nothing that can be done about it. Have a nice day. 😁

  • Blair Foster
    Blair Foster 24 days ago

    If you look at the big bang as a giant star in which we are a field leaving said star and imagine there is already a universe there outside said star even thou you may not see the surrounding universe we cannot assume that all other positions are exploding instead look around this event is rare overall suns blow up here and there the same can be exspected with known and unknown universes yet space itself likily has curviture that over great distances this positive -negitive curviture tends to determine different physics which in very likily

  • Shepard
    Shepard 25 days ago

    Why are we likely the first intelligence in our universe? Multiverse doesn't say anything about life in our universe.
    Also 10 billion years is far too much time for intelligence to first appear throughout the entire universe. Earliest intelligence should be at most 3-5 billion years.
    Even 10 billion years would leave a lot of possibilities for this universe which would make it impossible for us to be alone. Galaxy, maybe.

  • Riot4Peace
    Riot4Peace 26 days ago

    How many wheels does a unicycle have?

  • The Ultimate Warrior
    The Ultimate Warrior 26 days ago

    Before some years the definition of multiverse applied to universe and there was no multiverse.

  • yannick vignoles
    yannick vignoles 27 days ago

    Universe may be a sphere, as new discoveries seem to suggest. So it might not be infinite at all in the end.

  • MNorbert
    MNorbert 27 days ago

    Some alien life form bigger than us building a Large Universe Collider at the moment...

  • steelgreyed
    steelgreyed 28 days ago

    Personal belief and bias. Light itself is what is driving both the existence and expansion of the universe. so long as there is light, there will be a universe. Once the lights go out, everything it sustained collapses... (rather quickly actually)

  • Wayne Gygyx
    Wayne Gygyx 28 days ago

    Someone could be forgiven for thinking this is just speculation, and is likely an interesting mathematical model which likely has nothing to do with reality. I mean nobody's even INDIRECTLY observed another universe or a universe collision. The rate of new universe creation might be zero, or what you are calling a universe might actually look more like a particle than a cosmic scale thing like we observe own universe. Without data, you can't know. And since there are infinitely many speculative hypotheses, in the absence of evidence the probability of any one of them being true approaches zero.

    Also with respect to the Fermi Paradox part, how would we observe aliens who exist in a different universe? The Fermi Paradox applies to aliens living in OUR universe, not other universes.

  • Ralph Clark
    Ralph Clark 28 days ago

    I don't believe a word of it

  • Richard Wilcox
    Richard Wilcox 29 days ago +1

    Our planet is a part of our solar system.
    Our solar system to our galaxy.
    Our galaxy to our universe.
    Our universe to our multi-verse?
    Our multi-verse to our...?

  • 1112viggo
    1112viggo 29 days ago

    i wonder if the estimate for the number of possible universes corresponds to the estimated number of black holes in our universe

  • 0mn1vore
    0mn1vore Month ago +1

    Hold on... Objects can only move through space relative to each other at light-speed or less, but the expansion of space itself has no such speed limit. So why would a bubble universe's expansion have an arbitrary speed limit? [The speed of light, mentioned in the video.]

    • Burleigh Surfography
      Burleigh Surfography 29 days ago

      Yeah I’m with you on that one. It doesn’t make sense that it should be limited to light speed and have inflation forcing matter against the boundary. That would surely slow inflation, not increase it like we observe.

    • 0mn1vore
      0mn1vore Month ago +1

      @Burleigh Surfography - 12:04
      [edit] First mentioned around 1:40 ; just noticed the twelve-minute one is a callback to an earlier part of the video.

    • Burleigh Surfography
      Burleigh Surfography Month ago

      Yeah, that doesn’t sound right. What time in the video was it said? I can’t find it

  • David McKenna
    David McKenna Month ago

    I don't care what anyone says, Pluto is a planet and it always will be.

  • Jeff Hambleton
    Jeff Hambleton Month ago

    The problem with expanding bubble universes is you must assume that it has been doing this for an infinite time so what is space?

  • chris daffron
    chris daffron Month ago +1

    I got to be honest here. If the Jovoah's Witnesses that show up at my door step on Sundays were preaching about these sort of views of the Universe, I would politely send them on their way and lock the front door.

  • Chris
    Chris Month ago

    complete fantasy. the universe is electric. now stfu

  • Wilf Jones
    Wilf Jones Month ago

    There was no start and it will go on forever . Just 1 big bang of many . Time, ... no start no end , dont try to get your head around it . Its like everything else , a cycle . Energy cannot be created or destroyed , only transferred . Size ? Infinate . ....Another glass of wine wench .

  • Name Last Name
    Name Last Name Month ago

    we we will never know how many there are, so it doesn't matter really. why waste energy thinking about it.

  • Spritemon 98
    Spritemon 98 Month ago

    I'm pretty sure your definition and my definition of a multiverse are completely different

  • Kingace85
    Kingace85 Month ago

    any excuse but the simplest answer..

  • Balisongs for Breakfast

    Unless i missed something, how can you guys say indefinately that there even is a multiverse? Or that our universal bubble is plural?


    Karnodakshai Vishnu, Garbhodakshai Vishnu, Kshirodakshai Vishnu, Vishnu, mahavishnu, shiv, brahma

  • Jarrod
    Jarrod Month ago

    _Alan Guth invented inflation??_ Neat trick! How many universes did he create again?

  • escapetomars
    escapetomars Month ago

    Thanks for covering the planet definition issue in detail at the end, and giving air (finally) to the biggest problems with the definition. Great show as always.

  • Steve Lenores
    Steve Lenores Month ago

    The only way to observe a collision is with red shift anomalies. The only significant RSA is the Great Attractor which is hard observe because Milky Way disc is in the way.

  • James Hudson
    James Hudson Month ago

    one. anymore than one and they wouldn't be universes.

  • Madeline Cantu
    Madeline Cantu Month ago +10

    Imagine solving a whole ass universe theory just so you can win a shirt that was made in China for 10 cents

    • tom bradey
      tom bradey 5 days ago +2

      lol they did it for fun not for the shirt

  • dave
    dave Month ago

    On an aside from the subject matter of the video, that shirt is terrifying

  • Chief Seadawg
    Chief Seadawg Month ago

    "If you got this right, congratulations". 'Nuf said.

  • Scorch428
    Scorch428 Month ago +1

    I just find the fact that exact values in our universe exist.... weird.
    For example, if you drop any item in a vaccum on Earth, they all fall at 9.8m/s^2
    Why do they ALL at that specific value? 9.8?
    It's like that specific value was coded into a program. (our simulation)
    Maybe its just because Im a programmer, but in the real world, I kinda just expect pure randomness, lol.

  • praagyah
    praagyah Month ago

    How do we know that we don't exist in a bubble universe born out of a bubble universe born out of a bubble universe, etc?
    Would time progress similarly in all bubble universes?
    Could we exist in the youngest bubble universe so far?

  • Janusha
    Janusha Month ago

    Im going with the theory that.... If we had visited Pluto BEFORE we demoted it as a planet, we would never have demoted it as a planet. Because we expected a rocky lump of ice and stone. But what we found when we got there was definitely planet-like.

    BOSSL3V3L Month ago

    The real question is could we travel to another one? I wanna give an alien a bucket.

  • Azmath Khan
    Azmath Khan Month ago

    I challenge scientists can't imagine the Universes but how can they imagine the Creator. I bear witness there is no God but Allah.

  • Azmath Khan
    Azmath Khan Month ago

    How many humans have been born since the world was created until now? Anyone can count. Verily. Allah is Majesty. There is nothing like him. There is no God but Allah.

  • justspazzin 64
    justspazzin 64 Month ago

    LMAO! What a bunch of c.r.a.p.

  • Mustafa Sandal
    Mustafa Sandal Month ago

    Is there a creator Is the universe cyclical infinite

  • Kvera
    Kvera Month ago

    If Pluto is not a planet, midgets are not people.