What is the Universe expanding into?
What is the Universe expanding into?

Hey Crazies. Whenever someone starts talking about an expanding
universe there’s always at least one person asking
this: What is it expanding into? OK, we can tackle this, but I’m not sure
you’re going to like the answer. Demo time! Let’s say you have a balloon with some little
thingies attached. These represent galactic super-clusters, which
contain 10s of 1000s of galaxies. Yes, super-clusters. We don’t see the expansion of the universe
on scales any smaller than that because other forces like gravity are strong
enough to hold things together in spite of the expansion. Stick it to the man, galaxies!!! Alright, back to the balloon. These represent galactic super-clusters, whereas
the balloon itself represents space. If you blow air into the balloon, it expands
carrying the superclusters with it. They got farther apart without having to do
any actual moving in space. Pretty cool, huh? Well, hold up a sec. There are a few problems with this demo. First, we’re representing our 3D space on
a 2D balloon surface. The balloon demo is 1 dimension short. It really only represents a slice or cross-section
of the universe, but, then again, we drop from 3D to 1D in
spacetime diagrams all the time and nobody questions it. The second problem is the expanding balloon
has curvature, positive curvature. You can see it’s finite and has no edges. However! We said in the last video that all evidence
suggests we live in a very flat, zero-curvature universe
and, if it’s simple, an infinite universe. If that’s the case, this balloon is a terrible
model. On top of that, the fact that it’s only
a model can be misleading. This balloon is in a room full of air and
all sorts of other stuff. There’s a space it expands into. But none of that applies to the universe. Remember, the entire universe is everything. Even if the universe were finite like that
balloon… the balloon is all that there is. There is no room, no air, no person blowing
that air, just the balloon. So if that’s the universe, it’s not expanding
into anything. There is nothing outside it, not empty space,
literally nothing. Nothingness can be hard to imagine for a lot
of people, but your only other option is an infinite
universe and that comes with its own problems. You might wonder how the universe could have
gone from microscopic to an infinite size in a finite amount of
time. Well, it couldn’t have. If the universe is infinite, then it always
was for all measurable time. What?!? No, for real! While it is true that everything we can see
was, at one time, the size of microscopic speck. “Everything we can see” is just our observable
universe, not the entire universe and, if the universe is infinite, it solves
our nothingness issue because the universe can just expand into
itself. As space stretches, we get more and more space,
but, if space is infinite, that’s just more and more infinity. When you run the clock in reverse, a similar
thing happens. As space contracts, you just have less and
less infinity, but infinity is infinity, no matter how small. Infinity is so weird. There’s also no reason to assume that our
observable part is anything special. No matter where you are in this infinite universe,
you’ll see an observable part that’s about the same size, with you at the center. Further into the past, that bubble was a lot
smaller, denser, and hotter, but that was true everywhere. In an infinite universe, there is no edge,
there is no center and the big bang happened everywhere. Which kinda bothers me a little. If the universe is infinite and nowhere is
special, does that means there are also an infinity
of me out there somewhere beyond the cosmic horizon? Am I wasting my time cloning when I should
just invent FTL travel? I didn’t realize I was going to get to be on camera. If there are infinite possibilities, why does
it all look the same? What do you think? Are there infinite copies of all of us? Let me know in the comments. Thanks for liking and sharing this video. Don’t forget to subscribe if you’d like to
keep up with us. And until next time, remember, it’s OK to
be a little crazy. Hey, this is normally where I do comment responses,
but they were so good this time I turned them into this entire video. Don’t worry. We’ll still answer questions for this video
in the next one. Oh, and Joee Green, I’ll ask whatever science
question I dang well please. Alright crazies, thanks for watching!

100 thoughts on “What is the Universe expanding into?”

  1. Gauge Wiley says:

    Numberphile did a great video about how far you'd have to travel to find a clone of yourself

  2. Todd Laurette says:

    Good videos Bro, really gets u thinking, thanks!

  3. Pale Blue Dot Photography says:

    What if the universe is not expanding but everything in it is shrinking at the same rate?

  4. Sid says:

    Side Note: Universe is expanding because heat expands and it will continue to expand until absolute zero is attained.

  5. King Leonidas says:

    If bigbang was happened in every where in the 3d univeser, why it cant be every where in time? Maybe bigbang just is a wave of some thing still happen right now

  6. Brian Rodrigez says:

    Pohhh u dont know the answer. Just confess it….:) ignorance

  7. Monkey Robots Inc. says:

    universe is fake. pretty simple. havent you noticed?

  8. Xan Saif says:

    any thing chains happening >0 will happen

  9. Risto Paasivirta says:

    So that's how you got your clones!? Just travel far enough and find probabilistic copies of this universe, that's so easy!

  10. Mister Morteggio says:

    Of course cosmo is made out of infinite ourself. The point it's not space itself, but time, is time infinite? Entropy will made back our same univers along with infinite others again and again and again. Is time not infinite? We'll eventualt reach a point where nothing is left and time makes no sense, like there will be nothing, like before the singularity. "Nothing" is a strange thing it vomits out singulariries of every kind, ever and never toghether. Surely eternity is mine, sure this is the "n" tiime i live my life, but that's not what creeps out me. For until I'm just eternal but not infinite, what creeps me out is "nothing", and all the madness from beyond.

  11. suraj tiwari says:

    Infinity does not exist.

  12. Up-a-Creek says:

    Why would it have to be a copy of "us"?… my not just an infinite number of alternative life forms?… It seriously bothers me that Humanity claims it's the ultimate life form when it does so much to destroy itself… lol… if our distant "ancestors" were really one cell microbes… they are probably ashamed at what they evolved into…

  13. Shreyash Singh says:

    1:25 just use three rubber sheets perpendicular to each other rubber sheet instead of a balloon , then join a number near point objects each using 3 strings each perpendicular to the sheet it touches from all frames of references . now expand each rubber sheet and it represents expansion of 3d space .

  14. Matt says:

    Love the video! The part I find difficult to come to terms with, is what created all this, lets say there is a God (which I do think there is) – where did that entity come from? God parents? Then where did those entities come from? Something had to be at the start, but where did that come from? lol – maybe this is all some weird illusion and its not even really happening.
    We could just be part of some experiment and they made space expand so that we would simply be forever trapped in the simulation.
    Ok thats enough internet for today 🙂

  15. Gabriel C says:

    It's expanding because it all started with an explosion. The inertia from that explosion is still going, and will be going for a long time

  16. Akshay says:

    2:13 I wonder how nothing looks like😅

  17. Kari Lentz says:

    For decades after Hubble's law was discovered, the astronomy books touted it to mean that the galaxies were literally moving away from each other at the redshift velocities. Then, after about 1980, the narrative seemed to change to this "metric expansion of space", and thereafter, the astronomy books were gradually changed. The expansion of space, if real, would be caused by some unknown physics, that's why there is this talk about dark energy.

  18. Steve Doe says:

    I have always liked the idea of entropy. So…
    1. If the universe never stops expanding, does that mean universal entropy never reaches a maximum?
    2. If the universe does stop expanding, does that mean universal entropy can reach a maximum?
    3. If the universe contracts, does that mean it can become supersaturated with entropy? Does something have to change to maintain equilibrium? (I propose ‘time’ and wonder if this is prerequisite to Big Bang. Or, maybe this is how Neo gets so many chances as an anomaly in The Matrix.)

  19. Evan Parrish says:

    have you considered doing a video on E8? It's pretty fascinating even if it may have no real bearance on physics.

  20. Ryan Willis says:

    Yes I do believe that there are infinite copies of each of us. Each of them made or didn't make a choice that we ourselves on this Earth made. Some died early some lived longer and then there's us, the us that we know here.

  21. F3ynman1um says:

    If the universe is infinite than that means we will have to worry about heat death after an infinite amount of time

  22. Gt Ggj says:

    What is the nature of expanding is it like that space time gets expanded like baloon or new cells of space time just pop into existence between others?

  23. Daryl Leckt says:

    now I understand.
    prior to the big bang the singularity was infinite.

  24. Aditya Sharma says:

    By nothing do you mean absence of fields??

  25. Landon Griffith says:

    I like to think is the universe is like a puffer fish that infinitely expanding I don't know why is it a good analogy

  26. Florian Dutey says:

    Whats about living in a "kehr blackhole"-like pocket of space time?

    Such a blackhole is supposed to contain more volume of space inside than the volume it occupies outside by expanding into time (f im not wrong).

  27. Ethan Dupre says:

    This is my favorite science channel! Keep on, you weird weird lovable man.

  28. mamuburaa says:

    If there are higher dimensions like in string theory, the question of an infinite universe is almost irrelevant, since we're only experiencing a small slice of reality in our own part of spacetime which is already a tiny speck in the universe.

  29. Nigel P says:

    I like to imagine our universe as a flexible bubble surrounded by an infinite number of other bubbles. A bit like a kiddies ball pit.
    Maybe the bubbles have a limited interaction. Can we ever really know?

  30. Isco Ayala says:

    Infinite copies of ourselves? I don't think so…are bodies are too complex to be copied more than once…just my opinion

  31. Monkey Business says:

    That Thumbnail…..You were dead right. The Star of Chaos! The univserse is of course expanding into the Immaterium! Beware the Ruinous Powers that resider within!
    Blasphemy aside, though: great video, as always! 😉

  32. Contessa Adella says:

    The balloons model still works. We represent 3d space on the curved 2d surface….as said in the video. But the radius of that expansion from the centre of the ballon out to its rubber surface is an extra dimension….time. Further back in time the balloon was smaller and space (the surface) had less volume. In the future the radius (time) is lengthened and the corresponding balloon surface is larger (more space volume). So the universe is literally expanding into…..the future. Remember ALL of space is in the balloon surface….so as stated in the video there is nothing for the balloon to grow into…except the time direction..the future. Simples.

  33. Lee G. says:


    I dont believe that the universe is expanding. I think the red shift is caused by the distortions of all the stuff in space that light from distant stars and galaxies have to pass through for instance even if light passes through the faint gravity of dark matter it would have to bend the light some so that is what I belive is why the more soup of particles in "empty space" would appear to be red shifted and not that the universe is expanding causing the universe to appear to have expanded from a singularity

  34. Djinsoku XD says:

    The look of your eyes while blowing up the ballon… 😝😂

  35. Robert Ostler says:

    Is it possible that the expansion of the universe or dark energy is fueled by the formation of mass so as objects increase in Mass they push space out I kind of think of a tub of water and you freeze a part of that water the volume of water doesn't actually increase but the space in which it occupies does

  36. DaveB says:

    Empty space is nothing. People say not but why not? Empty space is said to be something as it contains matter / energy and thus dimensions but without matter / energy empty space is….. nothing!!! Perhaps this is just another conceptualisation issue…. This then leads to the question that if empty space is infinite does vacuum energy exist infinitely?

    Amazing channel by the way. Just found it and I'm totally hooked. Thanks for all the great info.

  37. Peter Black says:

    If the universe is an inflating balloon
    Will it end with a big bang

  38. Zeta Belotto says:

    Hey Mr. Science!! I know im late but, what if the expansión of the universe is compelled by the ever-increasing entropy of a never-ending system?

  39. Randy Smith says:

    pink floyd=infinity.

  40. ike muoma says:

    If the universe is infinite, it is a mathematical certainty there are multiple copies of us. Since a finitite amount of atoms can only be arranged into a finitie number of combinations. Hence repeatability is inevitable.

  41. Paul McNally says:

    Whats even more crazy that there is an actual answer (mind blown)

  42. Glenn Martyn says:

    I think there are many possibilities. What I've gathered from multiple theories is that the big bang could be the exit side of a black hole? Perhaps there are many black holes feeding the continuously expanded universe beyond our observable spacetime. And perhaps all the dark matter and dark energy are parallel universes sharing some of the matter and energy in our universe? It makes more sense to me with a black hole at the center of every galaxy, that perhaps every galaxy is its own universe feeding the wormhole to a new big banged galaxy/universe. The other galaxies we see could be parallel galaxies/universes to our Milky Way with slight to major differences? And every black hole at every galaxy center could continue fractaling into infinite parallel galaxy/universes that our beyond our observable space time infinitely! Just a thought….

  43. d mar says:

    good honest opinion

  44. Craig Z says:

    Chaos, apparently…

  45. Charlie Cross says:

    It's ok to be a little crazy but I take my meds just to be safe

  46. S C says:

    Into your mother.

  47. gaurav proton says:

    what? so many singularity points OK….. from they came from??

  48. Samee Faraji says:

    Hi Nick, could you please make a video about "zero energy universe hypothesis"?
    If you find it interesting enough 🙂

    I read a short article on Wikipedia, didn't understand everything. It would be nice,if you could make a video about it!


  49. Olaf Dilios says:

    the univers might not be expending, everything might just be shrinking 😉

  50. Aidar O' Sullivan says:

    3:26–3:31 This part totally blew my mind

  51. yarngod says:

    Nothingness doesn't exist (by definition) at any point in space or time. That leaves infinity the only way. We may all be totally unique since the variations of conditions are also infinite. There may be infinite similarity (in infinitely small number of cases) but it will never be identical.

  52. John Vonachen says:

    The universe needs to lay off the biscuits and gravy.

  53. Mike Diamond says:

    Stupid question time: near the beginning of the video you state that gravity holds things together in spite of the expansion. Is this proven science or does another explanation exist, such as: the expansion is only observable across greater distances, such as between superclusters; whereas the distances between the Earth and Moon are too small to observe such differences?

  54. Mike Diamond says:

    And thank-you for explaining the infinite vs. observable universe at the big bang @2:18 (ish) – I hate explanations that gloss over this.

  55. Irfan Mehmood says:

    Even an infinite universe has possible expansion into nothing. Its all beyond our 3D imagination of Space.

  56. dpolaristar says:

    Infinity is even worse than that, it basically means all possibilities WILL happen so statements like what is true and false break down since everything that is remotely at all possible is true.

  57. Peter Stark says:

    My take is that we are actually inside a black hole of another universe. Insead of space expanding the matter is actually schrinking. 😉

  58. Tyler Withers says:

    For a second i thought that the super clusters were scandium lmao

  59. Joey Gallagher says:

    Is there a measureable amount of friction of the universe expanding around particals gravitationally or molecularly bound? Like universal friction on the most sensitive level in which angular moment through our solar system, galaxy, observable universe, are accounted for. Will some minute measurable amount of preference in any direction shine through and maybe be able to tell us more about our trajectory through the universe on a level larger than that of the universe observable by "light". Bigger universe as observed by largest scale angular momentum. Sorry for lack of vocabs.

  60. Flip Flops says:

    I'm just glad to be alive in this time and space to watch your videos. Think about the odds, they are really really small

  61. The Red Enderman says:

    Scientifically There Could only be 168 Copies of Someone they would have an 8 in 168 chance of just being in the observable uviverse

  62. Nazir Lone says:

    Interesting.. But I remain intrigued… Perhaps all galaxies are destined to turn into black holes and all black holes to collapse into a dot and the cycle of life to begin again and my teacher to regale me with stories of Adam and eve.

  63. Marco Jiménez says:

    I love this video 😁

  64. Get outta here! says:

    LOL I'm just curious… Why did Joee green get rocked? I read his comment. And by the way my kids love your videos

  65. Protestant says:

    I rather believe in God

  66. Nati says:

    You dodged the question like George Bush dodging a shoe.

  67. ernest adamtey says:

    what if the surface of the balloon is round to us because we are three dimensional people. But to a two dimensional body on the surface of the balloon, the surface is flat.

  68. My name My last name says:

    But will the physics laws exist outside the universe?
    To what extent distance do the potential interactions with energy or particles would not apply as in our universe?

  69. Stephen Jackson says:

    The problem is that Newton's and Professor Entien

  70. Hans Isbrücker says:

    Sooo if the universe is infinite and originated in the big bang is the big bang a supertask? 🤔

    (Joking 🤪)

  71. Louange David MUGISHA says:

    Me i just watch your videos for the other guy when he comes in he sooo funny

  72. Mega Lâmpada says:

    I'm still waiting for the FINITE UNIVERSE model

  73. marloc2019 says:

    The infinity simply doesn't fit into my (tiny, little) mind.
    As well as the nothingness.
    These two concept are so abstract it's rather difficult to "immagine" them.
    This is the reason why we invented math.
    To describe something we simply can't imagine.
    And when it gets to bitter existential crisis, beside the math comes the meth.

  74. Rob T.V. says:

    We are infinity minus one

  75. George Coggins says:

    so does this mean the very bonds between my own atoms are expanding as well and if such is the case wouldnt it carry no point to study it as it is always relative

  76. Raphael Brandão says:

    There is a possibility that the universe has been infinity and the CMB is something else other than the big bang?
    Idk, like a super¹²³ nova explosion

  77. Simon James Odell says:


  78. Bridventure PR says:

    There is another perspective to this Q! Consider multiverse, where each universe has it's own big bang and related Spacetime matter-energy thingies, and surely their own post BB ages (ours is 13.8 Bys).

    One other thing each would hv is it's intrinsic expansion, right?! This is where my mind boggles, that some other universe (one or many) should meet our expansion. Still more boggling is, has it already happened? Remember in a multiverse there would be universes with different post BB ages.

  79. Ron Wilson says:

    Yes, the expanding balloon might have its limitations as a visual aid but even so your video clip say at 0:41 illustrates what seems to be an issue in that as the surface of the balloon expands so do the grid lines (if you had drawn them on the balloon) but that nice grid pattern in on the blue background does not expand and it is that which shows the balloon is indeed expanding. For there seem to be two rulers, the intrinsic one on the balloon surface that expands with the balloon (and hence one can't use that to measure the expansion of the balloon since it too is expanding) vs the extrinsic coordinate system as depicted by that blue background with the white grid lines that does show the balloon is expanding as the balloon fills more of that.

    So whether there is any grid outside the balloon there does seem to at least be two rulers here, and intrinsic one that expands with the balloon and an extrinsic ones that rather than stretches expands by adding new grid lines vs stretching the exiting ones. For if everything scales there is no way to know that the balloon is any larger given there is no fixed ruler to measure that expansion.

    Thus it seems the intrinsic ruler stretches but has the same number of ticks on it (albeit the distance between the tics increases) while the distance between the tics on the extrinsic ruler remains fixed but the ruler grows in size with that expansion (if not as your blue background is already hat large) by adding new tics as the balloon expands.

    So there seems to be three rulers here, the sensed distances ala relativity based on the observers point of view, the grid on the balloon that is stretched as the balloon expands,, and the fixed grid that shows that the balloon indeed is getting larger.

    Or is there some other way the balloon would know that it is getting larger without that third, fixed ruler in which to measure that expansion?

    And BTW, I think I might have asked this same question on a comment or two on some of your other videos, so I don't mean to keep repeating the same question but that visual at 0:41 illustrates this question quite well so maybe this question is thus worth repeating again here in that this video raises that question and at the same time shows that fixed grid a well that helps illustrate the issue. For I am not seeing how this all works without having some sort of fixed ruler whose ticks do not move. So am I missing something?

  80. Amit Yadav says:

    Do expanding universe affect the curvature of spacetime? If so , does Einstein's field equation account for the change in curvature ( gravitational field) with time around the massive body.

  81. m puri says:

    Hi. As a layman. May I ask a question? The observable universe is expanding. There are forces pushing and causing the expansion. Is there a chance that something very very big is outside the universe, which is attracting everything outwards leading to the expansion? Closer the galaxies are to this huge puller they speed up more. I shall be ever ready to learn.

  82. Andre Sant65 says:

    This I think is a fundamental difficulty that I frankly think that noone really can grasp. All we can do is say: OK, weird, let’s set it aside and keep on with other stuff. To be clear, it’s this:

    1) The universe is infinite. OK, weird, hard to imagine that something material is truly infinite. What? It goes on forever? There’s stuff everywhere forever? That’s way weird if you think about it.


    2) The universe is finite. One can talk about a space only using its own properties and never having to talk about what it might be in. One can even say that there’s no “in” involved since we never need it. Now go try to imagine that with a material universe – a thing with no location, where location is meaningless, where even an enclosing space is meaningless. That is also quite a strange thing.

    There are only two choices: infinite or finite with no enclosing space. Both way weird. This locks up my brain.

    The way to deal with it, I think, is to remember that we are just making useful models, ie analogies that are useful in some ways. The models can be useful even if there a few kinks that aren’t quite resolved.

  83. c1rcu1tn3rd says:

    Perhaps it's not so infinite but only appears that way to us. For instance, anywhere we move in the universe would be comparable to moving around the edge of a sphere. If you moved in one direction you'd eventually come back around to the same spot. Similar to traveling around the world. And the only way you could actually leave the universe would to punch it somehow. Perhaps black holes are actually punctures on this sphere? And they lead to the "inbetween" space that's not accessible to us. Just a theory.

  84. Charlie McGuire says:

    The number of numbers between 0 and 1 is infinite on the real numbers. This infinite set of numbers, doesn't even know that numbers like PI exist. It is possible to have an infinite number of things but something exist abstractly outside of it. Hence, we couldn't really know without observing it, whether there are any (infinite or not) copies of us.

  85. Lion Kimbro says:

    Is it possible that the universe is infinitely large, and that there are NOT infinite copies of us? May sound crazy, but — I've heard about "cardinality," a way of comparing infinities, and some infinities are larger than other infinities. If the number of possible arrangements of matter is a deeper infinity than the infinity of space, then the universe could be infinitely different in every direction. You could go forever and keep getting something different. I don't know if that's true or not, but it is conceivable to me that it is like this.

  86. itrath khursheed says:

    There should a video on both the theories of relativity.

  87. B. Dániel says:

    Dear sciencetist, please tell me something about the great attractor 😀

  88. gary liu says:

    Is there space before the big bang?

  89. jim liu says:

    Most science sites/ physics say the universe may be infinite.

  90. myantispambox says:

    Somewhere out there there might be civilizations lucky enough to actually see the edge, if it really exists.

  91. Neo Humanist says:

    No, sorry, but there are no infinite copies of you, not even one. Which is sad because you are making a great contribution to enlightenment! But hereś why. You might have an identical twin, or some other sort of clone, but that would not actually be you, or truly identical, but rather a different individual. There is only you. If there were actually more than one you–truly you, not just someone else who is physically indistinguishable from you–perception would not converge on a single point of view, but rather on more than one such points, which would render consistent perception impossible.

  92. Kevin Mark Barnes says:

    Dude i am german and i Love science, i Love sience asylum too…. so lucid you are a freak like me.. i found your channel and you got me:)

  93. Snaggledog 007 says:

    Just here to say Hi. And maybe learn something.

  94. Brett Cowen says:

    i'm probably gonna sound dumb asking this, but i will, if there's nothing outside the universe what would that look like, i mean even if it was nothing it would still look like something right, or am i not thinking the right way on it all.

  95. Duran says:

    The universe expands into an experiment table inside a lab made by aliens 👽 IT IS A FACT.

  96. Blue Carbon says:

    Nick Lucid: The Universe is expanding.

    Someone: What is it expanding in to?

    Nick Lucid: It’s not expanding into anything.

  97. Frank Herbert says:

    You should do a "best of…" Compilation video showcasing the wide variety of scientific topics that are covered by your channel. I'd love to have a broad spectrum video to share in social media in order to introduce Science Asylum to my friends and family. I could always just pick a couple of my favorites to share, but that would be like trying to draw objective conclusions from a small sample size…
    A compilation video, however, would show those connected to my social media the variety of topics as well as showcasing how you've grown as a host AND how your productions have matured… Though I use that term loosely lol
    Thanks for all the fun videos!

  98. OutLawStarGod Starwin says:

    What is it expanding from is it another dimension or nothing

  99. lordoftheflings says:

    This is very interesting when you said the universe was denser and hotter, everywhere, that is what the physicist Penrose concludes in his CCC or Conformal Cyclic Cosmology theory. Have you heard about it? What are your thoughts on it?

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