Check out more like this on our physics channel "Sixty Symbols" at: ruclips.net/user/sixtysymbols Including some more multiverse videos: bit.ly/MultiverseVids Details for Tony's book... Fantastic Numbers and Where to Find Them: A Cosmic Quest from Zero to Infinity Amazon US - amzn.to/3JYQbws Amazon UK - amzn.to/3M3yvB8 MacMillan US - us.macmillan.com/books/9780374600570/fantasticnumbersandwheretofindthem Penguin UK - www.penguin.co.uk/books/316/316964/fantastic-numbers-and-where-to-find-them/9780241445372.html
The first universe could expand forever making island universes in between. Gravity (Gravitons) would bring all the matter back to the center as a rain of High Energy Plasma of elementary particles. Gravitons would turn back and return to the center of the universe and accelerate all the matter making them high-energy particles. And then, they would cool down and become compact objects again. Likely, the first expansion of matter happened during the Vivatta Asaṃkhyeya Kalpa. And then, galaxies formed during the Vivattai Kalpa. The universe would contract during the Sanvatta Kalpa. Planets keep destroying during the Sanvattai Kalpa. If we put the first expansion of matter to the end, then Mahā-Kalpa starts from Vivattai Kalpa. I developed a theory to explain the expansion of the first universe. And I could derive the fundamental forms of matter that we call elementary particles.
If gravity was weaker, you'd presumably need to tweak other parameters (like the strength of dark energy) to stop matter flying appart too quickly. Weaker gravity would presumably mean slower creation of stars and planets too, and lower chance of larger planets with decent atmospheres to create a safe environment, and different orbits around stars and all sorts. I can imagine some counter effects to the increase in tech progress that lower gravity could cultivate
@@things_leftunsaid Yes, of course they can do a video on the topic, but not on the "dimesionality" of non-existent spacetime. Dimensionality is a subsidiary principle of form & structure, the metalogical principles that enable our concept & perception of places as having "space" and/or existing in a place having "space" and duration. Time is a conceptual construct or a measure of our limited perception of change. What changes is the totality of the 'field' of being's energy (enabling the present moment of the cosmos). So, the topic & its untestable, unprovable subject & concepts are pure nonsense, not science, nor holistic ontology concerning the reality of being (the cosmos).
@Joe Duke Bravo! Hence, the name is appropriate (i.e., "uni-" = unitary). It's also the only one we can perceive, detect, study, test, and prove real. Everything else is totally unscientific BS & sci-fi fantasy or fictional.
I enjoy Brady's "man on the street" approach, asking questions we would ask, while giving a platform (and brown paper with a Sharpie) for the experts to explain their topic. Well done series, and appreciated.
Man questions like 3:00 is why brady is one of the best in the biz, it was what I was wondering too. Thanks for all the effort you all put into these videos, they are fantastic.
He's an intelligent interviewer, something relatively rare in today's age. RUclips, of all things, is bringing that back, and it's always nice seeing someone ask probing questions that engage the interviewee that really lets their passion show.
I made a verifiable theory to derive the forms of matter and the universe. It is a much better theory than string theory. I could verify that theory using Buddhist teachings about fundamental elements, etc. So, I'm sure that it is the correct theory.
For anyone looking for some intuition about how you could 'hide' extra dimensions, imagine a flat 2D universe where you can move up/down and left/right. We could fold this plane into a vertical cylinder by connecting the left and right 'edges' together. Moving up/down would still move you as if you were in a flat 2D universe as normal, but moving left/right around the cylinder would quickly put you back where you started. If the radius of this cylinder was made arbitrarily small then moving left or right would effectively not change your position at all. Congrats, you've essentially turned a 2D universe into a 1D universe by hiding a dimension.
If you take the folded 2 →1 dimension and make it's length arbitrarily small, you get a 2D universe disguised as... wait, let's start with a 3D cube universe and make the height arbitrarily small before the folding transform, so it's a whole 3D universe; as for what's in it, no reason to assume the same kind of stuff as our universe, how about we put some kind of field with imaginary mass and the result is... another 3D universe with new forces and fields that is a non-interacting volumeless point particle. If the properties of this universe happen to satisfy the equations for some unsolved problem, well, it sure seems *convenient* that it's hiding and therefore it existence can't be disproven. Just the things that would need to be true for the equations you chose to explain some observed phenomenon, simply can't be helped that there's no way to try to falsify the hypothesis. Unfalsifiable, if you will.
@@cyborgninjamonkey I'll be sure to pass your skepticism along to the annual string theorist conference, where the world's leading physicists scour youtube comments for critique. Sarcasm aside, I'm not here to comment on what is or isn't - I'm just here to pass along an intuitive understanding of the discussion topic.
I think this has been one of my favourite "impossible to understand 10 dimensional multiverse"-type video. Very approachable conversation despite the complexity behind what is being discussed!
I'm far from a math dude (I did take Math up until I was a sophomore in college but stopped) but videos like this is why this is one of my favorite channels. They really distill complex problems enough that I can mostly understand yet fully appreciate.
@@GrandPianoGamer it refers to Brady Haran the creator and interviewer of the channel (along with computerphile, sixty symbols, periodic videos an some others..)
7:00 "computational power of an 'ultimate laptop' with a mass of one kilogram confined to a volume of one liter." The most computational physic-y thing I've heard
Saying String Theory is our best candidate for quantum gravity is such a contentious thing to say. A LOT of physicist would say string theory is highly unlikely to be true at this point.
If I may make a comment, Calabi-Yau compactifications of 10d strings are not the only way to go. String theory can in principle work in other dimensions and/or other backgrounds, and braneworld models offer alternatives to compactification. It's a wild landscape out there... beware of the swampland ;) cheers!
I dont get the multiverse thing. If there are multiple "universes" dont they make a single "universe" all together? Can the word universe even be plurial? Are "dimensions" just a misconception of orders of magnitudes/ocatves within the wave stucture of the universe?
@@ganonscrub Dark energy is an open problem in string theory. There are hints that is impossible to realize it as a positive cosmological constant within compactifications (this is the "de Sitter conjecture"). On the other hand, braneworld models arising from certain metastable vacua do yield positive cosmological constant (finding a stringy construction of this scenario was the result of a paper of mine, actually :) ), but it is yet to be established whether the rest of the physics would be as we want (namely general relativity + stuff, which in compactifications works perfectly). Yet another option is to realize dark energy in compactifications but not as a positive cosmological constant, rather as some sort of quintessence.
@@sk8pkl I would say that in this context "multiverse" refers to what is usually called a "landscape". That is, a set of possible realizations of the one physical universe. Different vacuum-like states of the same universe, if you will.
is it possible to find some fancy complex or hypercomplex manifolds into which we can compactify these extra dimensions and get a much smaller number than 10^272,000 perhaps something like 10^12 which is easier to search with a computer or something
"Speculative scientific ideas fail not just when they make incorrect predictions, but also when they turn out to be vacuous and incapable of predicting anything." (Peter Woit)
Sometimes you've got to wonder who the audience of the string theory videos is. It's at an odd balance between almost too complicated to explain to normal people and almost too simple a video to mean anything to those who know something. Difficult stuff.
I think that we have to be careful when interpreting "number of solutions" to a model as "number of extant cases". If we model the speed of a car that is slowing down as "Speed = SqRt(-x)", where x = 0 is the time that the car stops, we can see the curve of the car coming to a stop. But of course positive values of X are valid solutions to the equation, they just result in a speed with an imaginary component. Does that mean that the car has an imaginary speed after it stops? Well, i mean if we use the plain english definition of "imaginary", sure, but that's a semantic game. The truth is that our model of the universe gives many *real* solutions to the equation when x is negative, and many nonsense solutions to the equation when x is positive. So it's possible that a string theory model could provide 10^1000^2 solutions, but not all of those solutions reflect anything in reality. And similarly, when you look at your model and then observe the car instantaneously, you will find only one solution to your equation ever actually matches reality. Which means even if every solution in string theory is viable and a sensible solution which reflects a possible structure to the universe, it doesn't mean that all of those solutions are actually reflected in reality. Maybe only 7 of those solutions actually exist in reality, maybe only 1, maybe all of them.
You say "in reality". You cannot conceive any universe but your own so dismissing them on account of being imaginary is a mistake on account of being unable to even imagine a "different universe"
@@invictor2761 The fact that imaginary numbers don't reflect reality in this particular case doesn't mean that I'm not keenly aware that imaginary numbers are actually part of real meaningful solutions in quantum mechanics. I specifically said that comparing "imaginary numbers" to the common meaning of "imaginary" is a semantic game. I'm not going to play that game with you.
properly getting to those key questions, really shows how intuitively strong Brady Haran is, also that says why he's such a great scientific documentarian.
If I understood correctly, wouldn't this be the number of *types* of universes? So, more than one universe with the same type, or configuration, could exist at once?
Pretty sure this is what it's saying. So in our we still have the same physical constants, but then you have the extended family of possible multiverses having the same constants. Ones from our comos's inflation period, ones that might exist if the cosmos is infinite and therefore there are infinite hubblespheres.. and etc.
When theories predict crazy things that either cannot be tested or disagree with observations, the solution isn’t to discard the theory. It’s to layer even crazier theories on top of it.
String Theory has proven mathematically a lot of things that we see in the universe, and that other theories failed to explain, or predicted impossible when we could see that were happening. Currently is the best model of the universe that we have.
Here's some (hopefully constructive) criticism: Usually I really enjoy the more abstract videos but I felt this one was way too hand-wavy, and the explanation behind how one comes up with such a number remains as much a mystery after the video as it was at the start. I get that string theory is a super-complicated concept but then in terms of "math entertainment" I don't think I got anything out of this video.
I happened to see this video in a noisy environment. The hand waving remained conspicuous. I didn't gain too much, though the thickness of long plank limitations apply.
Two people were walking through the park when they came upon a chess board laid out all by itself on a table. "It looks like someone was in the middle of a game" "Yeah... Huh, it's funny, out of all of the possible configurations the board could have been in when we found it, that it should be THIS one that we find" "Do you think there's other chess boards in this park?" "It's not impossible" "Do you think every possible combination of chess board is here?" "Hah! No, the shear number of-" "Do you think there's a chess board where Hitler is a penguin???" "Excuse me?" This is basically what the multiverse conversation sounds like.
Yes! Except that somehow there is absolutely no way to look around the park to see if there be, in fact, any other chessboards, and if so, what they look like. All you can do is talk about the possibilities.
And then some physicists come up with Chess Theory, and get roundly criticised because there's no way to tell which of the vast number of possible chess games leads to the board configuration that was found.
@@ps.2 sure. But then you could also spend that time trying to find out if it's possible, doing something else that actually will make a difference in the world
I very much wish that the label "string theory" had not been applied to what is really the _search_ for a string theory. Scientifically, the term theory is meant to be reserved for frameworks that have survived rigorous empirical testing and are now considered foundational explanations of reality in fact. Calling it "string theory" makes it difficult to defend the theory of evolution, and the big bang to laymen who relate the term "theory" to unproven guesses.
no bc even though there's a large number of differences in position and time across dimensions it's limited - except if the properties of a universe (strength of gravity, etc) are also available to be changed bc you can go to infinitesimal changes with that
@@luckyw4ss4bi I think you hit the nail on the head. String theorists are mathematicians who wish they were physicists. Lord knows why - maths is lots more fun.
A manifold is a space "with no sharp edges". So a sphere is a manifold, but a cone or a pyramid is not. Compact means it is not infinitely big and all edges are included. If I say "all numbers bigger than 0 and less than 5" then there's no right edge right? 4.9 is not one because 4.99 is closer, but then again 4.999 is closer etc... 5 doesn't work because it isn't less than 5. We need to include the edges 0 and 5 for it to become compact. If you tried to put a bunch of pencils 90 degrees all to each other, you would find out that 3 is the maximum. We say that reality has 3 dimensions. If you tried to draw lines on a paper where each line is 90 degrees to each other you would find out 2 is the maximum, we say the paper has 2 dimensions.
@@methatis3013 For a manifold to have a certain dimension, means that if you cut out any piece of your manifold and straighten it out then it becomes a space with that many dimensions. So let's take a sphere, if you cut out a piece and straighten it out then it becomes like a flat paper, which has 2 dimensions. Thus a sphere has 2 dimensions. Let's say you have a circle. If you cut out a segment and straighten it out then it looks like a straight line, which has 1 dimension.
@@fyradur ah, ok, thanks. Now it's a bit clearer. But what would it mean in the context of string theory? Does it mean that each elemental particle has a multidimensional manifold around it? Does it mean that out entire universe has a couple of multidemnsional manifolds that curl all around it? Im having a hard time understanding in what way do these manifolds "interact" with our space (I know they don't necessarily interact in the real sense of the word. I meant just as an infinite amount of planes is incapsulated in our 3d space, does it mean that we are incapsulated in higher dimension space?)
What I don't understand is why extra dimensions are assumed to be 'compressed' or something similar. As I understand it, it's perfectly possible for there to be extra spatial dimensions that aren't compressed at all. We can't interact with them because we're only 3 dimensional and moving exclusively one direction through time, just like a 2D flatlander can't interact with the third dimension. They can still impact our daily life, but we might not recognize them as such right away depending on what that interaction looks like. Why are we so convinced that extra dimensions are hidden and completely undetectable?
Kudos to Numberphile team to keep the Numberphile alive. I guess the new content is so scarce that this is probably the first time the number was elaborated without any work done on the brown paper; Or maybe the 10-dimension is too complicated for a brown paper.
It's an infinite subject so unlimited content. Could always make anew video about a number or an update on it. They haven't even done one on my favourite number (4900, the cannonball number).
He must be very careful. If he bends over a little bit more, he might fold up to some dimensions by himself... Thanks for the upload. I dont understand it, but I get the idea. Thats enough for my universe.
Maybe I've misunderstood badly but the interviewee's tangent on Moore's law appears to be "because I pushed Moore's law past where it applies we can conclude civilizations is cyclical and other species live in low gravity universes"
Our existence could be a simulation in one of those super long lived universes with mass computing power. An experiment about which “abnormal” universal arrangements could produce sentient life. *takes another hit* a friggin mini-verse, like Rick and Morty.
I think string theory is largely pointless. A hypothesis that can't make testable predictions, or that is so amorphous it can predict anything, isn't a hypothesis at all. The math might be interesting for its own sake.
Just like prof Moriarty said on Sixty Symbols, "Just because it's beautiful and elegant doesn't mean it's right". And to this very day, String Theory can only provide 'hypothesis', with no actual experimental evidence or testable predictions whatsoever.
Are universes always completely insulated from each other, in other words is it always impossible for information to pass from one universe to another? And if so, what does it mean in practice to say that another universe, or whatever number of other universes, "exists"?
I agree it means nothing ! The question of the "existence" of something than cannot be tested with any experiment is not a scientific question.(As Wolfram Pauli said, the question is "not even wrong") Actually a significant number of physicists are unhappy with the last decades trend of "fairy tail physics". And of course the possibility that the string theory describes our universe is practically zero (not a single experiment supports it and the SUSY in witch it is based is dying) let alone the other 10^272,000-1 universes
These kinds of small pockets of conversations, comments within comments are more intresting and funny than the pocket dimensions and dimensions within dimensions he was trying to explain.
I think it's really interesting that we try to use our own experiences as a frame of reference for potential developments in universes entirely different from our own. Maybe that is also the actual answer to the Fermi paradox: we *have* encountered intelligent alien life. We just didn't recognise it as life because our own frame of reference failed to give us the perspective necessary to realise we are dealing with something alive.
I studied my MSc at Nottingham and if I remember correctly, Tony did say that he very much thinks string theory is on the right track. Of course the particular details are all subject to change. I'm sure even the people who came up with this number would not put any real stock in it. As Tony said, it's active research. So I think his gut feeling is that string theory is right (in fact I think he even said it was "obviously" right!), notwithstanding the details. But it was a few years ago that he told me this so maybe he has changed his outlook.
I think Tony was more ansewring the question as framed by this particular problem of number of possible universes. For String Theory as a whole, he has an entire video (awesome video, BTW) on Sixty Symbols explaining why it's solid and why he strongly believes in it.
I'd very much like him to state explicitly what possible developments - mathematical, theoretical or experimental - could lead him to change his mind about this approach to HEP. That shouldn't be a difficult question for a scientist to answer.
And for a completely opposite view, Sabine Hossenfelder abhors string theory for the almost religious sense of "it must be true because it would be so beautiful" and so far utter lack of testability. Oh well, nothing wrong with high-D mathematical recreations with uncertain spin-off, but let's please not call it mainstream physics yet.
I did my PhD in Physics at Cambridge (not in string theory), and as much as I respect all scientists who do great science, string theory has many many issues ... unfortunately. And it seems that the problems with string theory are only becoming bigger and bigger as we discover more.
The huge number is just possibilities of combination, not actual existing universe number. There are huge possibilities in even short gene DNA strings. But actual DNA combinations of existing and long extinct life forms are just tiny, tiny minuscular fraction of such possibilities. Same goes to the Universe. There may be trillions or trillion trillions of universes. Our universe is just very lucky one that can harbor viable galaxy and life. Of course there may be other lucky universes other than ours.
I'm not sure about any of this. Dark matter and dark energy sound too much like the aether. We can't see it, we can't directly detect it (only detect it's affects), but our current theories don't work without it.
Our current theories very much work without it, and that’s why it’s so mysterious! It’s that our current observations that don’t match our current theories that has produced theories on dark matter and dark energy.
In some distant multiverse some sentient creature has what we would recognise as a VR device and is able to simulate all of the these possible universes and experience them. For us it’s theoretical for them it’s entertainment.
The problem with string theory is that it's mentally pleasing, but fails to make any predictions about anything that can be tested with the scientific method... so it's more of a faith thing than a science thing, at least with current understanding. The only thing even remotely testable is supersymmetry, which is predicted by many models.
I wouldn't call it a "faith thing" so much as a "math thing". It's a mathematical model more than a scientific framework, but that requires at least logical consistency and peer review, making it more rigorous than just faith.
It makes several predictions, all of which can be tested with the scientific method, but the only problem is that it's far far ahead of it's time, we just don't have the technology yet to test these predictions. (well I personally think that we might have a chance at testing these predictions in the next few decades if we built a really advanced wakefield accelerator that's a 1000 km long lol we have that technology but it's in the early experimental stages also I don't think anyone will be willing to spend that much money on it)
I guess that the string theorists will never give up on string theory even though the only thing they can do is wave their arms and tell us that they are not going into "that". Bring on the unicorns. The most truthful statement made was "We just don't know".
@7:00 He has a point there… If you want to calculate the answer to life, the universe and everything, you will need to build a computer the size of planet Earth…
Tony: "people criticize string theory for just being a numbers game and being untestable" Also Tony: "but string theory is a really serious numbers game and also untestable"
More likely than not there are other universes and larger set of multiverse containing each smaller set within but none of that has anything to do with our universe which is likely finite and infinite in space and time.
Considering how short a time humanity has been around and the handful of years we have been able to think about this sort of stuff with any significance and assistance from technology (which is also still in its infancy), whatever we come up with about a subject this complex and huge is most likely going to be wrong. It may take billions of years (or the average existence of a species, which is counted in millions of years) for us to get this stuff right. It would be arrogant of us to think we can figure this out even in the current millennium.
11:30 and there is the problem. "Certain assumptions". I really don't like that about theoretical physics. It's like fantasy to me. Fun to watch and play with but completely useless in a realistic situation.
So howcome when people talk about the size of the universe it is often referred to as infinitely large, because the actual number might be so enormous it won't matter in modelling things, but in the case of the number of universes it's a set amount (which is still an insanely huge number)? I don't have the math skills to understand it on that level, but philosophically it makes me ponder.
Think about different TYPES of possible universes, instead of the actual number of them. The number of actual universes is a number between 1 and infinite (i know that doesn't help much...)
I enjoy how String Theory is both one of the best bets as to how the universe works and also we don't really know that much about how its supposed to work.
What does it mean for a dimension to be "so small we can't see them"? Since when is SIZE a property of a dimension? And if it is what's the size of time or the size of the second dimension?
There are no "dimensions" Three directions 90 degree from each other is just a practical way of measuring space. From every point there are infinite directions.
wait... it sounds like this is just looking at the results from one of the 5 theories that make up M-theory... I want to know how many possible universes M-theory as a whole allows for...
Thanks for this very interesting video. An impossible number of weird universes sounds really cool, however, as Richard Feynman said: "it doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiments, it is WRONG!". For example, results from the Large Hadron Collider have not showed evidence of several claims of string theory, like extra dimensions or supersymmetry.There are also many weird, unprovable hypotheses and concpets like negative energy... it makes the equations work somehow but no one really knows what they are. See Tony's expression at 4:35 when he's asked if string theory is wrong. This theory is so complex that no one can really say it is correct.
Great video. Thank you. I'm not against string theory in particular but the idea of this huge quantity of universes sounds a bit "unstable" to say the least. I think it is also influenced by the Copenhagen interpretation of quantum mechanics too. I really liked the last thoughts however, about trying to understand string theory. If we yet don't understand the probabilistic nature of quantum mechanics and the behavior of gravity (at the small scales) how can we pretend to know if string theory is right? Just some thoughts ahah C:
The real question is, does string theory predict the existence of a universe so long lived that is inhabitants will finally admit that string theory is wrong?
Funny, I remember a paper published around the same time that was claiming that many of the 10^500 universes originally posited were actually contradictory and physically impossible, so the actual number of actually possible universes was much smaller.
god I would just love a crash course exclusively over this subject. it's so complex that even in an amazingly explained video like this one, you're just scratching the surface of the mathematics and the theory behind it
String theory may be our best candidate for quantum gravity, but as I've heard from a professor/someone who's been doing research in the field for 20+ years, it also fails horribly at working with it, and there are many more convincing ways quantum gravity may work.
I see the String Fantasy is still throwing out impossible numbers to try and show that we should still be wasting time and resources on this failed hypothesis.
Is our means of measuring the universe limited by our perception of it? For example, we could measure the plank length to be the smallest possible size, but if that's as far as our limits of perception/comprehension go, we would have no way of knowing if it truly is the smallest possible size.
Check out more like this on our physics channel "Sixty Symbols" at: ruclips.net/user/sixtysymbols
Including some more multiverse videos: bit.ly/MultiverseVids
Details for Tony's book...
Fantastic Numbers and Where to Find Them: A Cosmic Quest from Zero to Infinity
Amazon US - amzn.to/3JYQbws
Amazon UK - amzn.to/3M3yvB8
MacMillan US - us.macmillan.com/books/9780374600570/fantasticnumbersandwheretofindthem
Penguin UK - www.penguin.co.uk/books/316/316964/fantastic-numbers-and-where-to-find-them/9780241445372.html
The first universe could expand forever making island universes in between. Gravity (Gravitons) would bring all the matter back to the center as a rain of High Energy Plasma of elementary particles. Gravitons would turn back and return to the center of the universe and accelerate all the matter making them high-energy particles. And then, they would cool down and become compact objects again. Likely, the first expansion of matter happened during the Vivatta Asaṃkhyeya Kalpa. And then, galaxies formed during the Vivattai Kalpa. The universe would contract during the Sanvatta Kalpa. Planets keep destroying during the Sanvattai Kalpa. If we put the first expansion of matter to the end, then Mahā-Kalpa starts from Vivattai Kalpa. I developed a theory to explain the expansion of the first universe. And I could derive the fundamental forms of matter that we call elementary particles.
If gravity was weaker, you'd presumably need to tweak other parameters (like the strength of dark energy) to stop matter flying appart too quickly. Weaker gravity would presumably mean slower creation of stars and planets too, and lower chance of larger planets with decent atmospheres to create a safe environment, and different orbits around stars and all sorts. I can imagine some counter effects to the increase in tech progress that lower gravity could cultivate
@@things_leftunsaid Yes, of course they can do a video on the topic, but not on the "dimesionality" of non-existent spacetime. Dimensionality is a subsidiary principle of form & structure, the metalogical principles that enable our concept & perception of places as having "space" and/or existing in a place having "space" and duration. Time is a conceptual construct or a measure of our limited perception of change. What changes is the totality of the 'field' of being's energy (enabling the present moment of the cosmos). So, the topic & its untestable, unprovable subject & concepts are pure nonsense, not science, nor holistic ontology concerning the reality of being (the cosmos).
@Joe Duke Bravo! Hence, the name is appropriate (i.e., "uni-" = unitary). It's also the only one we can perceive, detect, study, test, and prove real. Everything else is totally unscientific BS & sci-fi fantasy or fictional.
I enjoy Brady's "man on the street" approach, asking questions we would ask, while giving a platform (and brown paper with a Sharpie) for the experts to explain their topic. Well done series, and appreciated.
It's almost as if he trained as a journalist 😂
I absolutely agree. He more or less asked the questions I was about to be upset about, right when I wanted to ask them. 🔥
@@jack504 He's better than most journalists. Most of the time they just ask useless rhetorical questions.
no wonder he won A MEDAL OF THE ORDER OF AUSTRALIA
@@jack504 Perfect description of him: a math journalist.
I love how Brady doesn't pretend to understand it, but manages to ask really good questions on the spot.
ку, брудли
как жизнь сс13 админа?
asking good questions is a skill in itself
@@NoNameAtAll2 ого! Ну жизнь так себе с учетом того что сервера у меня нет, а еще меня пытаются загрифонить в ИРЛ. Ну а так все пучком.
Brady's probably smarter than you think. You just fall for the persona he creates.
It’s Brady’s superpower.
Man questions like 3:00 is why brady is one of the best in the biz, it was what I was wondering too. Thanks for all the effort you all put into these videos, they are fantastic.
And 4:32 as well.
I don’t know how he does it
He's an intelligent interviewer, something relatively rare in today's age. RUclips, of all things, is bringing that back, and it's always nice seeing someone ask probing questions that engage the interviewee that really lets their passion show.
I made a verifiable theory to derive the forms of matter and the universe. It is a much better theory than string theory. I could verify that theory using Buddhist teachings about fundamental elements, etc. So, I'm sure that it is the correct theory.
@@smlanka4u i dont think most physics papers accept that as a basis for theories
They used a giant sheet of the ritualistic brown paper just to write down one number that was already in the title. I love it.
LOL!!! Thanks! I needed that.
For anyone looking for some intuition about how you could 'hide' extra dimensions, imagine a flat 2D universe where you can move up/down and left/right. We could fold this plane into a vertical cylinder by connecting the left and right 'edges' together. Moving up/down would still move you as if you were in a flat 2D universe as normal, but moving left/right around the cylinder would quickly put you back where you started. If the radius of this cylinder was made arbitrarily small then moving left or right would effectively not change your position at all. Congrats, you've essentially turned a 2D universe into a 1D universe by hiding a dimension.
Wow thanks for sharing
backrooms = escaping the cylinder.
Very well put, this is a really intuitive way to think about this subject.
If you take the folded 2 →1 dimension and make it's length arbitrarily small, you get a 2D universe disguised as... wait, let's start with a 3D cube universe and make the height arbitrarily small before the folding transform, so it's a whole 3D universe; as for what's in it, no reason to assume the same kind of stuff as our universe, how about we put some kind of field with imaginary mass and the result is... another 3D universe with new forces and fields that is a non-interacting volumeless point particle.
If the properties of this universe happen to satisfy the equations for some unsolved problem, well, it sure seems *convenient* that it's hiding and therefore it existence can't be disproven. Just the things that would need to be true for the equations you chose to explain some observed phenomenon, simply can't be helped that there's no way to try to falsify the hypothesis. Unfalsifiable, if you will.
@@cyborgninjamonkey I'll be sure to pass your skepticism along to the annual string theorist conference, where the world's leading physicists scour youtube comments for critique.
Sarcasm aside, I'm not here to comment on what is or isn't - I'm just here to pass along an intuitive understanding of the discussion topic.
I think this has been one of my favourite "impossible to understand 10 dimensional multiverse"-type video. Very approachable conversation despite the complexity behind what is being discussed!
I'm far from a math dude (I did take Math up until I was a sophomore in college but stopped) but videos like this is why this is one of my favorite channels. They really distill complex problems enough that I can mostly understand yet fully appreciate.
Brody always asks very pointed questions! Amazing!
That's what so great about his channels. The questions are aways great
@Insert Username I don’t think so.
Who's "Brody"?
*Brady
@@GrandPianoGamer it refers to Brady Haran the creator and interviewer of the channel (along with computerphile, sixty symbols, periodic videos an some others..)
thanks a googol!
great insights as ever.
There's something provocative, perhaps profound, about the large Numberphile paper with nothing on it besides "10^272,000".
7:00 "computational power of an 'ultimate laptop' with a mass of one kilogram confined to a volume of one liter." The most computational physic-y thing I've heard
String theory is the most complex way to say "We don't know."
Saying String Theory is our best candidate for quantum gravity is such a contentious thing to say.
A LOT of physicist would say string theory is highly unlikely to be true at this point.
yes, very true...
And the rest would say that even if it were true, there is no way to confirm, or deny, it.
True
Or that it's "not even a theory".
What is quantum gravity?
If I may make a comment, Calabi-Yau compactifications of 10d strings are not the only way to go. String theory can in principle work in other dimensions and/or other backgrounds, and braneworld models offer alternatives to compactification. It's a wild landscape out there... beware of the swampland ;) cheers!
But do they factor in dark energy equations?
I dont get the multiverse thing. If there are multiple "universes" dont they make a single "universe" all together? Can the word universe even be plurial? Are "dimensions" just a misconception of orders of magnitudes/ocatves within the wave stucture of the universe?
@@ganonscrub Dark energy is an open problem in string theory. There are hints that is impossible to realize it as a positive cosmological constant within compactifications (this is the "de Sitter conjecture"). On the other hand, braneworld models arising from certain metastable vacua do yield positive cosmological constant (finding a stringy construction of this scenario was the result of a paper of mine, actually :) ), but it is yet to be established whether the rest of the physics would be as we want (namely general relativity + stuff, which in compactifications works perfectly). Yet another option is to realize dark energy in compactifications but not as a positive cosmological constant, rather as some sort of quintessence.
@@sk8pkl I would say that in this context "multiverse" refers to what is usually called a "landscape". That is, a set of possible realizations of the one physical universe. Different vacuum-like states of the same universe, if you will.
is it possible to find some fancy complex or hypercomplex manifolds into which we can compactify these extra dimensions and get a much smaller number than 10^272,000 perhaps something like 10^12 which is easier to search with a computer or something
"Speculative scientific ideas fail not just when they make incorrect predictions, but also when they turn out to be vacuous and incapable of predicting anything." (Peter Woit)
Such is the string theory
Sometimes you've got to wonder who the audience of the string theory videos is. It's at an odd balance between almost too complicated to explain to normal people and almost too simple a video to mean anything to those who know something. Difficult stuff.
But I guess its only for people who love science I guess
Same, it often gives an air of mysticism to it without ever even seeing the math that literally is the theory.
It’s for me. I’m not normal, but I don’t know anything.
I think that we have to be careful when interpreting "number of solutions" to a model as "number of extant cases". If we model the speed of a car that is slowing down as "Speed = SqRt(-x)", where x = 0 is the time that the car stops, we can see the curve of the car coming to a stop. But of course positive values of X are valid solutions to the equation, they just result in a speed with an imaginary component. Does that mean that the car has an imaginary speed after it stops? Well, i mean if we use the plain english definition of "imaginary", sure, but that's a semantic game. The truth is that our model of the universe gives many *real* solutions to the equation when x is negative, and many nonsense solutions to the equation when x is positive. So it's possible that a string theory model could provide 10^1000^2 solutions, but not all of those solutions reflect anything in reality.
And similarly, when you look at your model and then observe the car instantaneously, you will find only one solution to your equation ever actually matches reality. Which means even if every solution in string theory is viable and a sensible solution which reflects a possible structure to the universe, it doesn't mean that all of those solutions are actually reflected in reality. Maybe only 7 of those solutions actually exist in reality, maybe only 1, maybe all of them.
imaginary numbers exist as a concept, there is just application we can use them for in reality.
You say "in reality". You cannot conceive any universe but your own so dismissing them on account of being imaginary is a mistake on account of being unable to even imagine a "different universe"
@@saxy1player I literally said that perhaps all of them exist. I have no idea why you're criticizing a point I explicitly didn't make.
@@invictor2761 The fact that imaginary numbers don't reflect reality in this particular case doesn't mean that I'm not keenly aware that imaginary numbers are actually part of real meaningful solutions in quantum mechanics.
I specifically said that comparing "imaginary numbers" to the common meaning of "imaginary" is a semantic game. I'm not going to play that game with you.
properly getting to those key questions, really shows how intuitively strong Brady Haran is, also that says why he's such a great scientific documentarian.
If I understood correctly, wouldn't this be the number of *types* of universes? So, more than one universe with the same type, or configuration, could exist at once?
Pretty sure this is what it's saying. So in our we still have the same physical constants, but then you have the extended family of possible multiverses having the same constants. Ones from our comos's inflation period, ones that might exist if the cosmos is infinite and therefore there are infinite hubblespheres.. and etc.
That's how I understand it.
It did take Dr Strange a while to work out which one could defeat Thanos. So yeah, I'm comfortable with this number.
Compared to the number in this video, Dr Strange's 14,000,605 is essentially zero!
When theories predict crazy things that either cannot be tested or disagree with observations, the solution isn’t to discard the theory. It’s to layer even crazier theories on top of it.
String Theory has proven mathematically a lot of things that we see in the universe, and that other theories failed to explain, or predicted impossible when we could see that were happening. Currently is the best model of the universe that we have.
@@josecorchete3732 what are some predictions it has made that have been shown to match observations?
@@peterromero284 Black holes, dark matter detection, quantum computing.
@@josecorchete3732 I’m sorry but none of those have anything to do with string theory
Here's some (hopefully constructive) criticism: Usually I really enjoy the more abstract videos but I felt this one was way too hand-wavy, and the explanation behind how one comes up with such a number remains as much a mystery after the video as it was at the start. I get that string theory is a super-complicated concept but then in terms of "math entertainment" I don't think I got anything out of this video.
I happened to see this video in a noisy environment. The hand waving remained conspicuous. I didn't gain too much, though the thickness of long plank limitations apply.
It really felt like the universe nodded at him by moving the paper after he said it had positive vacuum energy at 4:19
Two people were walking through the park when they came upon a chess board laid out all by itself on a table.
"It looks like someone was in the middle of a game"
"Yeah... Huh, it's funny, out of all of the possible configurations the board could have been in when we found it, that it should be THIS one that we find"
"Do you think there's other chess boards in this park?"
"It's not impossible"
"Do you think every possible combination of chess board is here?"
"Hah! No, the shear number of-"
"Do you think there's a chess board where Hitler is a penguin???"
"Excuse me?"
This is basically what the multiverse conversation sounds like.
Yes! Except that somehow there is absolutely no way to look around the park to see if there be, in fact, any other chessboards, and if so, what they look like. All you can do is talk about the possibilities.
And then some physicists come up with Chess Theory, and get roundly criticised because there's no way to tell which of the vast number of possible chess games leads to the board configuration that was found.
@@ps.2 sure. But then you could also spend that time trying to find out if it's possible, doing something else that actually will make a difference in the world
I very much wish that the label "string theory" had not been applied to what is really the _search_ for a string theory.
Scientifically, the term theory is meant to be reserved for frameworks that have survived rigorous empirical testing and are now considered foundational explanations of reality in fact.
Calling it "string theory" makes it difficult to defend the theory of evolution, and the big bang to laymen who relate the term "theory" to unproven guesses.
So, basically, it's a hypothesis.
@@mikedoe1737 It's many different and incompatible hypotheses. We don't even know if it's even possible to test most of them.
What makes a hypothesis in science is that we can test them. String Theory isn't testable to begin with
@@adamqazsedc He says string theory predicts negative vacuum energy. Since the vacuum is everywhere... why can't we test it's energy?
omg these are my favourite Numberphile videos, those about big numbers with Tony. I love it!
Prof. Padilla is always interesting.
10^500, then 10^272000 -- may as well work all the way up to infinity.
no bc even though there's a large number of differences in position and time across dimensions it's limited - except if the properties of a universe (strength of gravity, etc) are also available to be changed bc you can go to infinitesimal changes with that
That's what you get with scientific theories with no proof.
A wonder if this number could ever be big enough that string theorists would start doubting string theory.
Mathematicians are rarely dissuaded by extremely large numbers :)
I would think if anything, it would cast more doubt on string theory if the number was too small!
@@luckyw4ss4bi I think you hit the nail on the head. String theorists are mathematicians who wish they were physicists. Lord knows why - maths is lots more fun.
If 10^272,000 doesn’t do it, then no, I don’t think so.
field theories have infinite number of possible vacua, so maybe we should throw away all field theories lol
Entertaining as it Is, this is no longer science but just mathematical mindsturbation.
Cosmological Constipation
String Theory do be like that
"There's a compact manifold that wraps up six extra dimensions"
Like wow, man. That sounds so funky and groovy.
roflmao
A manifold is a space "with no sharp edges". So a sphere is a manifold, but a cone or a pyramid is not.
Compact means it is not infinitely big and all edges are included. If I say "all numbers bigger than 0 and less than 5" then there's no right edge right? 4.9 is not one because 4.99 is closer, but then again 4.999 is closer etc... 5 doesn't work because it isn't less than 5. We need to include the edges 0 and 5 for it to become compact.
If you tried to put a bunch of pencils 90 degrees all to each other, you would find out that 3 is the maximum. We say that reality has 3 dimensions. If you tried to draw lines on a paper where each line is 90 degrees to each other you would find out 2 is the maximum, we say the paper has 2 dimensions.
@@fyradur what would it mean for a dimensiom to be a manifold though? How would you illustrate that?
@@methatis3013 For a manifold to have a certain dimension, means that if you cut out any piece of your manifold and straighten it out then it becomes a space with that many dimensions.
So let's take a sphere, if you cut out a piece and straighten it out then it becomes like a flat paper, which has 2 dimensions. Thus a sphere has 2 dimensions.
Let's say you have a circle. If you cut out a segment and straighten it out then it looks like a straight line, which has 1 dimension.
@@fyradur ah, ok, thanks. Now it's a bit clearer. But what would it mean in the context of string theory? Does it mean that each elemental particle has a multidimensional manifold around it? Does it mean that out entire universe has a couple of multidemnsional manifolds that curl all around it? Im having a hard time understanding in what way do these manifolds "interact" with our space (I know they don't necessarily interact in the real sense of the word. I meant just as an infinite amount of planes is incapsulated in our 3d space, does it mean that we are incapsulated in higher dimension space?)
What I don't understand is why extra dimensions are assumed to be 'compressed' or something similar. As I understand it, it's perfectly possible for there to be extra spatial dimensions that aren't compressed at all. We can't interact with them because we're only 3 dimensional and moving exclusively one direction through time, just like a 2D flatlander can't interact with the third dimension. They can still impact our daily life, but we might not recognize them as such right away depending on what that interaction looks like. Why are we so convinced that extra dimensions are hidden and completely undetectable?
Kudos to Numberphile team to keep the Numberphile alive. I guess the new content is so scarce that this is probably the first time the number was elaborated without any work done on the brown paper; Or maybe the 10-dimension is too complicated for a brown paper.
It's an infinite subject so unlimited content. Could always make anew video about a number or an update on it. They haven't even done one on my favourite number (4900, the cannonball number).
He must be very careful. If he bends over a little bit more, he might fold up to some dimensions by himself... Thanks for the upload. I dont understand it, but I get the idea. Thats enough for my universe.
I love videos with Tony Padilla!
what a great interview. Full of information. Well done to both interviewer and interviewee
Only one number written on the Brown Paper. Brilliant 👏
"Not only is the universe stranger than you think, it's stranger than you *can* think!"
- Werner Heisenberg
Maybe I've misunderstood badly but the interviewee's tangent on Moore's law appears to be "because I pushed Moore's law past where it applies we can conclude civilizations is cyclical and other species live in low gravity universes"
5:05 “…you can imagine it quite easily…well, not easily, no one knows how to do it.” LOL.
Our existence could be a simulation in one of those super long lived universes with mass computing power. An experiment about which “abnormal” universal arrangements could produce sentient life. *takes another hit* a friggin mini-verse, like Rick and Morty.
I loved that whole idea about universes with weaker gravity could harbour more advanced intelligence. What a psychedelic episode.
I think string theory is largely pointless. A hypothesis that can't make testable predictions, or that is so amorphous it can predict anything, isn't a hypothesis at all.
The math might be interesting for its own sake.
Just like prof Moriarty said on Sixty Symbols, "Just because it's beautiful and elegant doesn't mean it's right". And to this very day, String Theory can only provide 'hypothesis', with no actual experimental evidence or testable predictions whatsoever.
didn't he say that all solutions had a negative energy? seems testable
Are universes always completely insulated from each other, in other words is it always impossible for information to pass from one universe to another? And if so, what does it mean in practice to say that another universe, or whatever number of other universes, "exists"?
I can give you any answer you want to hear because for nothing in your question is ANY proof.
@@Richard-ox6zk I'm very sorry, I don't understand what you mean by "because for nothing in your question is any proof."
I agree it means nothing ! The question of the "existence" of something than cannot be tested with any experiment is not a scientific question.(As Wolfram Pauli said, the question is "not even wrong") Actually a significant number of physicists are unhappy with the last decades trend of "fairy tail physics". And of course the possibility that the string theory describes our universe is practically zero (not a single experiment supports it and the SUSY in witch it is based is dying) let alone the other 10^272,000-1 universes
@@GaryDunion Yeah I have no idea what that guy was talking about. What he said wasn't even English lol
These kinds of small pockets of conversations, comments within comments are more intresting and funny than the pocket dimensions and dimensions within dimensions he was trying to explain.
I think it's really interesting that we try to use our own experiences as a frame of reference for potential developments in universes entirely different from our own. Maybe that is also the actual answer to the Fermi paradox: we *have* encountered intelligent alien life. We just didn't recognise it as life because our own frame of reference failed to give us the perspective necessary to realise we are dealing with something alive.
Yup that's already one of the solutions. Life can exist in unrecognizable ways.
Bigger question is: how did you comment on this video 6 hours before it was published.
@@M4rtingale Only thing i could think of is them bein a member but u cant become a member on this channel...
@@M4rtingale so idk
@@M4rtingale maybe they are a patreon member and got it released while it was unlisted
I feel like watching this is what watching any normal video would seem like if you were high out of your mind
I studied my MSc at Nottingham and if I remember correctly, Tony did say that he very much thinks string theory is on the right track. Of course the particular details are all subject to change. I'm sure even the people who came up with this number would not put any real stock in it. As Tony said, it's active research.
So I think his gut feeling is that string theory is right (in fact I think he even said it was "obviously" right!), notwithstanding the details. But it was a few years ago that he told me this so maybe he has changed his outlook.
I think Tony was more ansewring the question as framed by this particular problem of number of possible universes.
For String Theory as a whole, he has an entire video (awesome video, BTW) on Sixty Symbols explaining why it's solid and why he strongly believes in it.
I'd very much like him to state explicitly what possible developments - mathematical, theoretical or experimental - could lead him to change his mind about this approach to HEP. That shouldn't be a difficult question for a scientist to answer.
And for a completely opposite view, Sabine Hossenfelder abhors string theory for the almost religious sense of "it must be true because it would be so beautiful" and so far utter lack of testability.
Oh well, nothing wrong with high-D mathematical recreations with uncertain spin-off, but let's please not call it mainstream physics yet.
Maybe he was hoping the LHC would find evidence of supersymmetry?
I did my PhD in Physics at Cambridge (not in string theory), and as much as I respect all scientists who do great science, string theory has many many issues ... unfortunately. And it seems that the problems with string theory are only becoming bigger and bigger as we discover more.
Brilliant video, great questions and visualisations and loads of enthusiasm from Tony who had me captivated from the start! So interesting!
The huge number is just possibilities of combination, not actual existing universe number. There are huge possibilities in even short gene DNA strings. But actual DNA combinations of existing and long extinct life forms are just tiny, tiny minuscular fraction of such possibilities. Same goes to the Universe. There may be trillions or trillion trillions of universes. Our universe is just very lucky one that can harbor viable galaxy and life. Of course there may be other lucky universes other than ours.
Is it unavoidable that only one of the dimension can be "time"? What would multiple time dimensions imply?
That was my question!
Can the other dimensions be temporal? Or is it always 1 time X spacial?
Multiple timelines existing simultaneously and able to interact, I think.
Remember to always terminate your String theories with a \0.
I'm not sure about any of this. Dark matter and dark energy sound too much like the aether. We can't see it, we can't directly detect it (only detect it's affects), but our current theories don't work without it.
Dark matter is actually less unknown than dark energy
Our current theories very much work without it, and that’s why it’s so mysterious! It’s that our current observations that don’t match our current theories that has produced theories on dark matter and dark energy.
In some distant multiverse some sentient creature has what we would recognise as a VR device and is able to simulate all of the these possible universes and experience them. For us it’s theoretical for them it’s entertainment.
I've been watching numberphile for over a decade now, still so enjoyable!
The problem with string theory is that it's mentally pleasing, but fails to make any predictions about anything that can be tested with the scientific method... so it's more of a faith thing than a science thing, at least with current understanding. The only thing even remotely testable is supersymmetry, which is predicted by many models.
All hail experimental evidence!
I wouldn't call it a "faith thing" so much as a "math thing". It's a mathematical model more than a scientific framework, but that requires at least logical consistency and peer review, making it more rigorous than just faith.
It makes several predictions, all of which can be tested with the scientific method, but the only problem is that it's far far ahead of it's time, we just don't have the technology yet to test these predictions. (well I personally think that we might have a chance at testing these predictions in the next few decades if we built a really advanced wakefield accelerator that's a 1000 km long lol we have that technology but it's in the early experimental stages also I don't think anyone will be willing to spend that much money on it)
I guess that the string theorists will never give up on string theory even though the only thing they can do is wave their arms and tell us that they are not going into "that". Bring on the unicorns. The most truthful statement made was "We just don't know".
Yes
@7:00 He has a point there… If you want to calculate the answer to life, the universe and everything, you will need to build a computer the size of planet Earth…
There's a great science fiction story by a physicist called Cosm which explores universal darwinism.
Tony: "people criticize string theory for just being a numbers game and being untestable"
Also Tony: "but string theory is a really serious numbers game and also untestable"
String theory is a busted theory being held onto by researchers trying to not lose their funding.
No, sorry, just 1 uni-verse of infinite dimensionality.
More likely than not there are other universes and larger set of multiverse containing each smaller set within but none of that has anything to do with our universe which is likely finite and infinite in space and time.
@@douche8980 Wow, that seems kinda cool, as long as logic, making sense, causes, and scientific testing & proof don't matter.
I love this show so damn much. Please don’t ever stop making content
Don't you get an infinite number of potential universes based upon the quantum wave function?
Considering how short a time humanity has been around and the handful of years we have been able to think about this sort of stuff with any significance and assistance from technology (which is also still in its infancy), whatever we come up with about a subject this complex and huge is most likely going to be wrong. It may take billions of years (or the average existence of a species, which is counted in millions of years) for us to get this stuff right. It would be arrogant of us to think we can figure this out even in the current millennium.
Arrogant and improbable but not impossible.
@@Baggytrousers27 Also true.
@@joyl7842 So are we simply surrender and stop trying?
@@pastafarianpanda5731 Not at all. If anything we need many more scientists and engineers because there is so much more to be done.
I really love the questions you ask, man! This makes the video way more informative and interesting.
11:30 and there is the problem. "Certain assumptions". I really don't like that about theoretical physics. It's like fantasy to me. Fun to watch and play with but completely useless in a realistic situation.
So howcome when people talk about the size of the universe it is often referred to as infinitely large, because the actual number might be so enormous it won't matter in modelling things, but in the case of the number of universes it's a set amount (which is still an insanely huge number)?
I don't have the math skills to understand it on that level, but philosophically it makes me ponder.
Think about different TYPES of possible universes, instead of the actual number of them. The number of actual universes is a number between 1 and infinite (i know that doesn't help much...)
@@juanausensi499 That does make slightly more sense to me.
500 to 272k? It got worse? 2b? I thought Witten got that sorted out...
I enjoy how String Theory is both one of the best bets as to how the universe works and also we don't really know that much about how its supposed to work.
This guy looks like he has really attractive body odor
“I’ve told you countless times…”. I see what you did there.
What does it mean for a dimension to be "so small we can't see them"? Since when is SIZE a property of a dimension? And if it is what's the size of time or the size of the second dimension?
There are no "dimensions" Three directions 90 degree from each other is just a practical way of measuring space. From every point there are infinite directions.
String theory is just mumbo jumbo.
wait... it sounds like this is just looking at the results from one of the 5 theories that make up M-theory... I want to know how many possible universes M-theory as a whole allows for...
The postulated hyper-civilisation could be the one running the simulation in which we exist.
Any experimental evidence to back up string theory?
Imagining what could other universes offer and look like by fantasizing about the level of technology and speed of computer... quite sad I would say!
Now that's the real Multiverse of Madness
the fact that you need 10 dimensions to make this idiotic theory work should tell you all you need to know about its veracity
Thanks for this very interesting video. An impossible number of weird universes sounds really cool, however, as Richard Feynman said: "it doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiments, it is WRONG!". For example, results from the Large Hadron Collider have not showed evidence of several claims of string theory, like extra dimensions or supersymmetry.There are also many weird, unprovable hypotheses and concpets like negative energy... it makes the equations work somehow but no one really knows what they are. See Tony's expression at 4:35 when he's asked if string theory is wrong. This theory is so complex that no one can really say it is correct.
Bravo SS!!! Great, succinct retort.
There was a toy when I was a kid in the early 90's that you can use a pencil and paper on and it showed you unlimited forms. The same as shown here.
It's a bit like Graham's Number: The solution might be 10^27000, but it could also be something like 14.
1:38 cinematic indeed
this guy is the Rodger Federer of numberphile
They all exist in a superposition until observed, in which case the universal wave function collapses and only one actually exists. This one.
Great video. Thank you. I'm not against string theory in particular but the idea of this huge quantity of universes sounds a bit "unstable" to say the least. I think it is also influenced by the Copenhagen interpretation of quantum mechanics too. I really liked the last thoughts however, about trying to understand string theory.
If we yet don't understand the probabilistic nature of quantum mechanics and the behavior of gravity (at the small scales) how can we pretend to know if string theory is right?
Just some thoughts ahah C:
I feel like this one was really a Sixty Symbols.
10:40 sounds like that universe is boiling
The real question is, does string theory predict the existence of a universe so long lived that is inhabitants will finally admit that string theory is wrong?
Funny, I remember a paper published around the same time that was claiming that many of the 10^500 universes originally posited were actually contradictory and physically impossible, so the actual number of actually possible universes was much smaller.
So I was drawing universes with that Spirograph as a kid?
Haven't we reached "string theory isnt a theory" yet?
I love that string theory gives you an excuse to have cool psychedelic graphics like at 2:40
god I would just love a crash course exclusively over this subject. it's so complex that even in an amazingly explained video like this one, you're just scratching the surface of the mathematics and the theory behind it
String theory may be our best candidate for quantum gravity, but as I've heard from a professor/someone who's been doing research in the field for 20+ years, it also fails horribly at working with it, and there are many more convincing ways quantum gravity may work.
I see the String Fantasy is still throwing out impossible numbers to try and show that we should still be wasting time and resources on this failed hypothesis.
my brain hurts thinking about the size of that number.
Is our means of measuring the universe limited by our perception of it? For example, we could measure the plank length to be the smallest possible size, but if that's as far as our limits of perception/comprehension go, we would have no way of knowing if it truly is the smallest possible size.