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First you follow the logical progression of the spatial dimensions... I recently simplified my explanation of the logical progression of the spatial dimensions even more and I'm gonna leave it here. let me show you the logical establish pattern so you can understand better, infinite amounts of 0 dimensional existence can stack into any size one dimensional existence because it is nothing and infinite amount of nothing can stack in any size version of something. 1D equals length only. Now infinite amounts of one-dimensional existence can stack into any size two dimensional existence because it is length and now that you've added width in so then infinite amounts of one dimensional existence can stack inside of it. Now infinite amounts of two dimensional existence can stack into any size three dimensional existence because this is length and width and now you add depth... When we add in depth we allow for infinite stacking of two-dimensional planes to stack into any size three dimensional existence because of the additional depth dimension. Now given this logically established pattern we can conclude that if a fourth spatial dimension exist then infinite amounts of three dimensional existence can stack into any size 4 dimensional existence... This means that if a fourth spatial dimension exist our universal potentiality of our three-dimensional universe will be compressed down into a relatively flat state which is exactly what we observe of our universe. This means if a 4th spacial dimension exists (as verified by this logical progression pattern that aligns with our observations) then infinite three-dimensional universal potentiality can stack into ANY SIZE 4D existence making a infinite 3d multiverse the norm... This explains Mandela effects. Once you have this you can understand that if a higher spatial dimension exists like shown then the relative state or shape of the universe should be compressed into a flat State as observed but in the higher dimensions you're absolutely correct that it is a different shape and is round in the 4D and toroidal in the 5D and this established pattern continues.
Euclidean doesn't exist in our world... There's truly nothing no existence that is euclidean in our 3D... If you zoom down far enough you will see the structures Fall apart to a curved nature...
You just need to understand magnetism itself and understand that it is a toroidal vortex with opposite spinning vortices... You can look up the replicable experiment under the channel Theoria apophasis... CRT cathode ray television proof of magnetic vortex.
17:31 "For example if you lean right you probably miss this story..." So, two things, 1st, we still don't know which news are factually correct or not (in part or its entirety), if you read news that are bias no matter the side, then you are not reading news, just opinions. The other thing that is interesting is that you gave an example of how you might get a "better picture" of something by telling people that lean to the right that they might be missing information about a figure they might approve or like, which to me sounds like bias, because you did not give an example the other way around, also, we don't know if both of the news are factually correct as stated on the 1st one. Though the idea of the application is good, we are just dealing with rotten tomatoes on one barrel and the same on the other barrel, and you don't get to "balance" your diet by eating 2 rotten tomatoes. Besides that, excellent video.
First of all, where would all of that coal come from? Thermodynamics, y'know. Does the universe synthesize what it uses to power itself by some cosmic chemistry somehow? Thermodynamics still applies, and there's also the problem of running out of materials eventually when all of the usable energy from the coal is spent. This doesn't make sense all around.
Anywho, what would be a mechanism for the Big Bang in any respect, given that it was an infinitely condensed point, and there was no tangible matter to be formed or chemistry to be done just yet?
There are probably so many other questions I'm missing here. But anyways, what I'm saying is that your "theory" is even worse than the EU "theory". There's literally no evidence for the Universe being powered by coal anywhere in any sense. It'd be wise to straighten up, put down your fake science, and learn real science.
I simply cannot fathom how you delivered such a complex subject in an accessible and comprehensible fashion. this here is one of the best science videos I've ever watched (and I've had my fair share of years watching these)
Thats not how gravity works 4:22... gravity around a point mass is always attractive and never repulsive. A photon travelling past a point mass therefore only curves into one direction... towards the mass, not away from it.
There are other things too. - Saying that a hyperbolic plane "curves inward" is a bit of a strange choice of words, and the pringle shown hardly displays the characteristic saddle shape, so a reasonable person might draw the conclusion that "hyperbolic" means "cylindrical" (which will then lead to much confusion later on in the video). I don't really understand why they're avoiding the word "saddle" here, frankly. If you want to draw on a pringle, nothing is stopping you from calling it saddle-shaped rather than "inwardly curved". - Saying that the CMB is "the largest picture of the universe we can observe" is technically true but is phrased as though that means every other way of looking at the universe is strictly _smaller,_ which is not true. It's smaller _or equal._ - And of course, then going on to say that it's "the farthest back in the history of the universe we can see with light" implies that there are still other ways of observing beyond that time and/or distance, by using means other than light. That's not correct, nothing else can look farther either. - Saying that the 2D topologies shown are finite is very unclear. You might argue that they're in fact infinite because you can keep going in one direction without running into the edge of the shape, which is exactly the opposite sense of "finite" which is intended--namely that only the mobius band can be infinitely _extended._ - Saying that a torus can be unfolded to a Euclidean plane without changing its geometrical properties is seemingly contradictory with the definition of topology given earlier because it's badly phrased. - The explanation given about closed loops also does not clearly enough exclude gravitational lensing duplicating the image of an object, which might lead to confusion about why gravitational lensing is not proof of the topology of the universe. This is an incredibly messy video.
18:30 Game devs had to make a work around for this kind of thing yrs ago when hardware wasn't enough to fully render full 3D environments. They came up with a 2D texture that appears to look 3D. This is called ' Bump Mapping '
The game eco also have an torus shaped planet that is rendered to look like a sphere. It's because you can't have an regular tiling of an sphere but it works for an torus. It feels so weird with an seemingly spherical planet lacking an north and south pole.
As a Geometrist who’s worked on the classification of Riemannian Manifolds (basically, the 18 ones she mentioned), this video is so well done! Good job, Jade, this is one of your best works so far!
@@specialrelativity8222 Good question! I think it depends a lot on your background and aspirations. Assuming you already know Differential Topology/Smooth Manifold Theory, I can suggest three equally valid textbooks: John Lee - Introduction to Riemannian Manifolds; Manfredo do Carmo - Riemannian Geometry; Peter Petersen - Riemannian Geometry. If you don’t know Differential Topology yet, then you really should start from that. I’d suggest John Lee - Introduction to Smooth Manifolds, but you won’t need every topic. To get into Riemannian Geometry you need to be comfortable with: Smooth Manifolds and maps between them, submersions and covering maps; the tangent bundle, and vector bundles in general; sections of vector bundles, in particular vector fields; knowing how to write ODEs on smooth manifolds; tensor constructions of vector bundles. This should be good for a more Mathematical approach to the field, which, nonetheless, doesn’t disdain the Physics. If instead you just care about General Relativity, then it’s a different story.
Me "what's the shape of the universe?" Scientists: "We don't know, buuuuuut we know a girl who will make the most entertaining way to tell you that over about 20 minutes" ❤❤❤❤
@@nicknac1980 I wanted to write that but I was not sure if it would be considered inappropriate. One unfortunately has to be careful in this day and age with compliments...
"Your theory of a donut-shaped universe is intriguing, Homer. I may have to steal it." - Stephen Hawking to Homer Simpson in S10 Ep22 They Saved Lisa's Brain (1999)
8:30 I could not thank you more for this clarification! All videos mention flatness of the universe as if all viewers understand what is meant by flat.
Lol, I should have checked the comments first. This irritated me so much I paused the video to immediately comment on it myself, then noticed you'd already pointed it out.
Great editing work on this video! I laughed several times at the (quasi rhetorical) question followed by snappy cutaway. Very playful, and it works perfectly with Jade's sparkling style of delivery.
Thank you sir! I'm not against watching long format videos, but I've been burned so many times watching 20 min videos for NOTHING to be answered and only going over information I already know.
Except, there's nothing stopping you from making a donut shaped coffee mug or a coffee mug shaped donut. The shape is not inherently dangerous. The material is the danger. Guess topology is better than we give it credit for.
No offence, but as a topologist i really hate to see people think about topology like that, topology is not about saying that "donut and a coffee mug are the same bc you turn one in to another" no, topology is about generalizing concept of continuity, compactness and other calculus stuff, which leads to things like toplogical spaces one of which is a torus(or if filled a donut) and yes, topology is about finding which spaces are same or more accurately homoemorphic bc then we can tell that some spaces have some properties bc it's "same" as the other one which we know it has, but it doesn't give a damn about real geometrical objects like a donut and a cup, it's like saying that geometry is field of mathematics which can construct a pentagon with a compass and a straightedge
I genuinely think this is, in all of my many years on RUclips, absolutely my most favorite channel. Thank you for never slowing down, and thank you for always making education so accessible! :)
@dixee6498 I hear you, but for reals, unless she's already a friend, keep it to yourself. And I know the fear of saying that to a friend, I know the pain of losing a friend for saying it... but I also know the joy of telling a friend who loved me back 😉... everyone in your life is important, but we all have our own thread in the weave, and eventually some one will leave, but don't stop weavin, and eventually you'll find your reason. ❤✌️
The diagram at 4:25 does not support the idea of a geodesic very well, since there would be no reason for the object(photon) to bend leftward and then return to its original heading. Rather, the interaction would cause a quadratic curve-overall, a deflection from its original heading. If light really acted like that, then you wouldn’t even realize that the light path was bent by the presence of the sun, which relies on the displacement of the position of the source.
As someone who has contemplated this very question for decades, I want to thank you for making this video. It's so refreshing to hear someone deal with this subject honestly. Every time I hear some famous scientist say, "well, we think the universe is flat because it looks flat," I want to pull my hair out. As this video illustrates, the appearance of flatness can be easily explained by the size of the whole relative to the portion you are able to measure. It baffles me that so many learned minds are unable to recognize the cognitive dissonance of believing that the universe is infinitely large and simultaneously believing that the portion we can measure is large enough to prove that. We maaaay one day be able to prove that the universe is a closed shape. But you can NEVER prove that it is flat.
If the universe turns out to be doughnut shaped, I hope it is sour cream. Great crumb texture and tasty vanilla glaze is the best reality one could ask for.
This is one of the few scientific videos that I can say I genuinely enjoyed! Great pace and magnificent delivery of an otherwise dense and tedious content. Great job!
4:22 That representation of the path of light is a bit absurd, isn't it? Shouldn't it look like an hyperbolic trajectory? If light is going dead center towards the CoM of the planet/star it won't get curved, it will just collide with it.If light behaved in the way shown. planets would be effectively transparent/invisible.
The path should be straight until it gets close to the mass where it gets effected by the gravity of the mass. That is where it is bent on a path that can be approximated by a hyperbola. The curve is always inward toward the mass and only when it is near the mass. It will not curve outward from the mass. After it gets farther away from the mass it will be going effectively straight again. The path would therefore be a straight line before the mass in a direction that off center of the mass. There will be bending near the mass and only towards the mass. Then effectively the path straightens out again after the mass. Actually, she has a picture of the light bending around a mass on the general relativity plaque on the wall behind her. However, it looks like that plaque may be a bit off on the edges. edit: let me add one more thing besides what I said below: the path of light around a spinning black hole can be complicated. Google: research gate Gravitational Lensing by Spinning Black Holes in Astrophysics, and in the Movie Interstellar. There are some diagrams there on it.
Yeah, I don't understand why every science channel always portrays it wrong like that. The trajectories look basically like trajectories from an actual lens. Not these sudden bends away from the center of mass.
Although the duration of this video was 18 minutes but it felt like 5 minutes. What a nice and simplified explanation of complex topics in a friendly manner. Great work mam.
She showed 3 2d analogies. Maybe the other 15 are rotations etc. I can see the edges of a cube joining up to the other edge in a hyper torus ma y ways.
SO good and so well put together and no expectations you'd cover everything but i'd like to point out that in terms of the CMB the "objects" represent actual sound waves moving through the medium of the universe at that time because we have a good sense of the density (it was really dance) at that moment that the universe became translucent enough to set light out on it's way, we can do fourier (and other ) analysis to find waves and calculate the size of a wave. that gives us a sense of the size an observed object "should" be so we can compare it
One must remember the Cosmic Microwave Background is not complete. What we see is merely that portion which was able to reach our detectors. The complete picture can be infinite.
It is impossible to be infinite, that means there was enough time for all the stars to go through heat death already, it had a beginning and that scares people bc of the implications.
@@jamesharmon4994 How about you actually trying refuting what I said. If the universe is infinite, whatever that means, how is it we can still see stars outside? Should there not have been enough time for them to all suffer heat death?
Great explanations! I felt like each subtopic could be expanded to make whole videos ^^ Also, your expressiveness and gentle voice make your videos pleasant to watch.
The biggest unanswered question in this video (that science has yet to acknowledge and is frankly concerning): how does the music at 18:25 slap so hard?
There are some confusing inaccuracies here: 1) As later pointed out in the video, the curvature being too small to measure is not what prevents us from determining topology, as even perfectly flat geometry can have multiple different toplogies 2) The light trajectories on the flat torus are actually straight, they are not just geodesics (lines of minimal curvature) curved by the curvature of space itself. The curvature in the illustration comes from the visualization, it actually shows a curved torus, not a flat one. The flat torus is later visualized in the video with the square where you come back at the other end when walking out. 3) Switching from the curved torus to the flat torus *does* change fundemental geometry (from half-hyperbolic half-elliptical to euclidean). What is not changing is the *topology*
I think you're mixing up extrinsic and intrinsic curvature. A torus does not have intrinsic curvature, so light goes straight rather than following geodesics. But the path is still extrinsically curved (well, except when viewed from within the torus). If you add intrinsic curvature to a torus, I believe you simply get a Klein bottle
1:15 Simple answer: Lable the areas ABCD A ||\ B-C ||/ D Each area has a "state"; you're either "in" that area, or you're "out" (i/o). You can only be "in" one area at a time. Crossing a bridge changes the state of both areas it's attached to: i>o or o>i The number of times an area's state changes equals the number of bridges it has. B =4 A,C,D =3 If the state changes an odd number of times, the final state is opposite from the start. If the state changes an even number of times, the final state is the same as the start. If you start in B, you'll end in B: B: i>i However you'll also "end" in A, C, and D as well. A,C,D: o>i You can't start or end in B. If you start in an odd number area, you'll "end" in the other 2. i>o o>i o>i So, NO, you can't cross all bridges only once.
I think about the shape of the universe all the time it's actually one of the most complex questions I like to ponder. Thanks for sharing this incredible information.
The entirety of the observable universe. Not the entirety of the whole universe. The flatness of the observable universe, could also be interpreted as a local flatness that doesn't necessary apply to the rest of the universe. Unfortunately we'll never know.
It's worse than that. The mind examine the mind itself, and can't see out of it. I call it the "dog principle". Science is based on the assumption, that since we can outsmart a dog 7 times out of 10, therefore we can understand the universe. It's all based on a dog and nothing else.
@@AncientWildTV Also, there is one thing, greatly overlooked. That's saying, the ants look up the sky and see nothing. Dogs are howling the moon. We humans, we see and know everything, or at least having the capacity of. This logical jump bothers me. Measuring what there is to the dog, I find it suspicious. I mean, making a postulate of any being slightly more intelligent than a dog, is nothing short of perfection, sounds ridiculous to me I mean, people can look up the sky, make observations, it's fine. But stop barking!
As always, Jade's videos are overflowing with this wonderful positivity and humor while still managing to explain complex ideas. I wish I could bring clones of Jade into every school on the planet as their respective physics teacher, heck I even wish I could turn back time and have a clone of Jade as my own teacher. But the clones would definitively need to have the sound effects from these videos as well, flipping the hair should make that sound in real life too! 💜
12:55 i swear i remember a "game" that simulates this where you are in a spaceship and there is an earth that repeats depending on the topology of the universe you chose, it was so trippy Edit: it's curved spaces from geometry games :D
Are you talking early 90's ish? I have a vague memory of a spaceship game that seemed like it was always repeating as well. I don't remember any other details though.
@@davidfoster5561 no, its a computer game but i found it! its called Curved Spaces on the Geometry Games site, Topology and Geometry Software it has flat, hyperbolic and spherical universes all ready for you to fly in
I love the whoosh and you speak to a different camera angle. So fun! Your videos are great and I get excited to learn 100 things every time I watch one.
If the torus is large enough, the universe would expand faster than the speed of light - meaning the light from your backside would never reach your eyes.
The possible topology of the universe on very *small* scales is interesting too - it could be responsible for the fundamental quantum fields that give our reality the form it has.
Imagine a universe where walking in one direction brings you back to where you started, but everything is mirrored left to right. To you it would look like a flipped version of your world. But you couldn’t survive because of the chirality of molecules (twist direction of molecules changes their effects). Most things you'd eat or breathe would likely kill you... You'd need to take another round-trip fast to stay alive!
I don't think there would be a problem because of the chirality of molecules: all molecules would be reflected, so the position of direction-sensitive molecules relative to others would not be altered.
@@jaimecastano8745 not the molecules in your body, you would have brought them around the trip with you. It’s as if you would have brought your house key with you, it wouldn’t fit the lock in the (to you) mirrored world.
@@qb0816 the molecules you rely on for survival-like amino acids and sugars-would likely behave completely differently, potentially rendering them toxic.
Seriously?! I love this girl! Not just she's pretty, but she is truly smart! She is something I'd like as a life partner! Granted, I'm way too old for that young lady... but one can dream, right?! Can I give more than one upvote to her, please?!
Is the order of the pictures on the wall behind you a test? Because it keeps changing. Just like the position and rotation of the table and the globe. I like the pictures. It is so nerdy to have entropy, GR, Math and QM on the wall. Btw the true shape of Elon Musk is undistorted fascism.
I don't feel smart enough to say for certain, but the visual of the background pictures feel like they relate to the topic. As for the globe, it was directly used at one point, so the room was rearranged a couple of times and there were multiple film cuts for editing. I don't think it was intentional. Kinda the same with the pics, I think they changed them after the first one or two cuts, but they're pretty consistent afterwards. The shape of Musk is that of an entitled child of wealth stumbling through the world.
I have a couple of questions: - can you really bend the cylinder into the torus? The 'inside' of the torus is a shorter path than the outside so you have to distort the cylinder. - how do cosmologists tell the 'actual' size of the cool or warm spots in the CMB? Wouldn't all methods of measure be affected by the topology of the universe?
In topology there is an operation that welds edges of a shape together. So in your example, we would weld the two circles of the cylinder together. That doesn't distort the cylinder. It retains any surface curvature.
@@mrpocock Thanks, but that doesn't really address the issue. See, a cylinder has the 2 circles you mention but to turn it into a toroid the 2 SIDES have to bend. 1 bends into a small circle & the other bends into a large circle. So a (say) 2" cylinder long enough to bend into a (say) torus with a 2" hole, the small side will be ~6.28" but the long side will be 18.84. i.e. the donut hole has diam 2 x 3.14 while the external circle is 6 x 3.14. (2" hole + 2 x 2" diam of cylinder. So I can't see how a cylinder can transform into a torus without 'magic' to alter the dimensions. Note: I do understand in topology one can stretch & distort however one wishes, but the discussion is about possible reality, not maths concepts. Can actual space be compressed or stretched to accommodate such things? Or do we accept it as just more fantasy from Physics done by Maths?
@@markmcd2780 the stretching and distortion is an artifact of measuring distances and angles in 3d space, not in the 2d space defined by the cylinder surface. Before deforming it, you could grid out the surface of the cylinder. Then bend and glue it onto the torus. Then continue to measure distance on the torus using that (now distorted) mesh. It entirely depends upon if you are bound to the surface, with that defining your coordinates, or if you are unbound. We're bound to the universe, so we see geometry defined by its 3d surface.
@@mrpocock I'll be honest & say I have no idea what any of that means. Is it mystical catechism to invoke the sub-ethereal trans-universe? A magical formula for making 5 = 1.2? Seems to me the 'mesh' is going to be wildly distorted to fit on the cylinder. Maybe we could use it as an FTL drive? take a cylinder of space, bend it into a tor5us then move to the inner side to travel then back out to the destination? 🤫
@@KastorFlux 😆All those comedians out of work & you're looking for a job...😄 But hey, near as I can tell, until you leave the esoteric world of theoretical topology, anything might be possible. The question is, what could be real. I'd be curious just what kind of a Big Bang could produce a toroid universe - or anything except an expanding sphere. Near as I can tell, anything else requires something OUTSIDE the universe to shape it.
Really fun video! The diagram at 4:21 give the wrong impression, though - that light ray was already heading straight toward the massive object. It would have had to be travelling on either side to then follow the curvature (like an Einstein Cross).
It's always a treat to see a new video from you. Very intriguing video, I must say. It left me pondering parallaxes and the CMB. Our planet has moved 435.6 billion kilometers since the discovery of the CMB. It would seem that we could get some level of parallax on the CMB if we compare the earliest images to the most modern ones. Surely that would be informative to this subject
I've always wondered why the seemingly arbitrary rules of topology were what they are. It being a descendant of graph theory makes it make so much more sense!
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First you follow the logical progression of the spatial dimensions... I recently simplified my explanation of the logical progression of the spatial dimensions even more and I'm gonna leave it here. let me show you the logical establish pattern so you can understand better, infinite amounts of 0 dimensional existence can stack into any size one dimensional existence because it is nothing and infinite amount of nothing can stack in any size version of something. 1D equals length only. Now infinite amounts of one-dimensional existence can stack into any size two dimensional existence because it is length and now that you've added width in so then infinite amounts of one dimensional existence can stack inside of it. Now infinite amounts of two dimensional existence can stack into any size three dimensional existence because this is length and width and now you add depth... When we add in depth we allow for infinite stacking of two-dimensional planes to stack into any size three dimensional existence because of the additional depth dimension. Now given this logically established pattern we can conclude that if a fourth spatial dimension exist then infinite amounts of three dimensional existence can stack into any size 4 dimensional existence... This means that if a fourth spatial dimension exist our universal potentiality of our three-dimensional universe will be compressed down into a relatively flat state which is exactly what we observe of our universe. This means if a 4th spacial dimension exists (as verified by this logical progression pattern that aligns with our observations) then infinite three-dimensional universal potentiality can stack into ANY SIZE 4D existence making a infinite 3d multiverse the norm... This explains Mandela effects. Once you have this you can understand that if a higher spatial dimension exists like shown then the relative state or shape of the universe should be compressed into a flat State as observed but in the higher dimensions you're absolutely correct that it is a different shape and is round in the 4D and toroidal in the 5D and this established pattern continues.
Euclidean doesn't exist in our world... There's truly nothing no existence that is euclidean in our 3D... If you zoom down far enough you will see the structures Fall apart to a curved nature...
You just need to understand magnetism itself and understand that it is a toroidal vortex with opposite spinning vortices... You can look up the replicable experiment under the channel Theoria apophasis... CRT cathode ray television proof of magnetic vortex.
In 4D the rainbow is tubular...
17:31
"For example if you lean right you probably miss this story..."
So, two things, 1st, we still don't know which news are factually correct or not (in part or its entirety), if you read news that are bias no matter the side, then you are not reading news, just opinions.
The other thing that is interesting is that you gave an example of how you might get a "better picture" of something by telling people that lean to the right that they might be missing information about a figure they might approve or like, which to me sounds like bias, because you did not give an example the other way around, also, we don't know if both of the news are factually correct as stated on the 1st one.
Though the idea of the application is good, we are just dealing with rotten tomatoes on one barrel and the same on the other barrel, and you don't get to "balance" your diet by eating 2 rotten tomatoes.
Besides that, excellent video.
A mobius universe would be quite a twist.
Aren't you the person who composed the whallop of crankery that is the Coal Powered Universe?
First of all, where would all of that coal come from? Thermodynamics, y'know. Does the universe synthesize what it uses to power itself by some cosmic chemistry somehow? Thermodynamics still applies, and there's also the problem of running out of materials eventually when all of the usable energy from the coal is spent. This doesn't make sense all around.
Anywho, what would be a mechanism for the Big Bang in any respect, given that it was an infinitely condensed point, and there was no tangible matter to be formed or chemistry to be done just yet?
There are probably so many other questions I'm missing here. But anyways, what I'm saying is that your "theory" is even worse than the EU "theory". There's literally no evidence for the Universe being powered by coal anywhere in any sense. It'd be wise to straighten up, put down your fake science, and learn real science.
@@Gordy-io8sb The coal-powered universe was a joke.
I simply cannot fathom how you delivered such a complex subject in an accessible and comprehensible fashion. this here is one of the best science videos I've ever watched (and I've had my fair share of years watching these)
Oh Gosh. How I miss the time the Universe simply traveled on turtleback. 😔🐢🐢🐢
😂😂😂😂😂
Truly nostalgic
It's turtles all the way down!
😂😂😂
Not to worry! The topology of the universe doesn't really affect whether the world can exist within it perched on the back of a turtle.
Thats not how gravity works 4:22... gravity around a point mass is always attractive and never repulsive.
A photon travelling past a point mass therefore only curves into one direction... towards the mass, not away from it.
Spotted same thing , school boy error I guess
There are other things too.
- Saying that a hyperbolic plane "curves inward" is a bit of a strange choice of words, and the pringle shown hardly displays the characteristic saddle shape, so a reasonable person might draw the conclusion that "hyperbolic" means "cylindrical" (which will then lead to much confusion later on in the video). I don't really understand why they're avoiding the word "saddle" here, frankly. If you want to draw on a pringle, nothing is stopping you from calling it saddle-shaped rather than "inwardly curved".
- Saying that the CMB is "the largest picture of the universe we can observe" is technically true but is phrased as though that means every other way of looking at the universe is strictly _smaller,_ which is not true. It's smaller _or equal._
- And of course, then going on to say that it's "the farthest back in the history of the universe we can see with light" implies that there are still other ways of observing beyond that time and/or distance, by using means other than light. That's not correct, nothing else can look farther either.
- Saying that the 2D topologies shown are finite is very unclear. You might argue that they're in fact infinite because you can keep going in one direction without running into the edge of the shape, which is exactly the opposite sense of "finite" which is intended--namely that only the mobius band can be infinitely _extended._
- Saying that a torus can be unfolded to a Euclidean plane without changing its geometrical properties is seemingly contradictory with the definition of topology given earlier because it's badly phrased.
- The explanation given about closed loops also does not clearly enough exclude gravitational lensing duplicating the image of an object, which might lead to confusion about why gravitational lensing is not proof of the topology of the universe.
This is an incredibly messy video.
same here.
During WWII, the Soviets simplified the 'bridges in Königsberg' question by destroying some of the bridges.
Hahahahahaaaaaaaaaaaaaaaaaaaa
Lol
Lmao
Reaching simplicity is a sign of genius 😂
r/technicallythetruth
18:30 Game devs had to make a work around for this kind of thing yrs ago when hardware wasn't enough to fully render full 3D environments. They came up with a 2D texture that appears to look 3D. This is called ' Bump Mapping '
i loved this era of video game graphics
The game eco also have an torus shaped planet that is rendered to look like a sphere. It's because you can't have an regular tiling of an sphere but it works for an torus. It feels so weird with an seemingly spherical planet lacking an north and south pole.
As a Geometrist who’s worked on the classification of Riemannian Manifolds (basically, the 18 ones she mentioned), this video is so well done! Good job, Jade, this is one of your best works so far!
I am never forget the day ... metrization of continuously differentiable ... this I know from nothing.
Riemann!? For some big prime (call it P) the gap that follows tends to be on the mean (the logarithm base e)!
Life is peaches for the few. The rest can go into the Black Hole. No?
what is the best book to learn reimannian geometry??
@@specialrelativity8222 Good question! I think it depends a lot on your background and aspirations.
Assuming you already know Differential Topology/Smooth Manifold Theory, I can suggest three equally valid textbooks: John Lee - Introduction to Riemannian Manifolds; Manfredo do Carmo - Riemannian Geometry; Peter Petersen - Riemannian Geometry.
If you don’t know Differential Topology yet, then you really should start from that. I’d suggest John Lee - Introduction to Smooth Manifolds, but you won’t need every topic. To get into Riemannian Geometry you need to be comfortable with:
Smooth Manifolds and maps between them, submersions and covering maps; the tangent bundle, and vector bundles in general; sections of vector bundles, in particular vector fields; knowing how to write ODEs on smooth manifolds; tensor constructions of vector bundles.
This should be good for a more Mathematical approach to the field, which, nonetheless, doesn’t disdain the Physics. If instead you just care about General Relativity, then it’s a different story.
"I'm not sure even he could draw 3D topologies as viewed from the 4th dimension" ngl, I was expecting a Brilliant Ad here..
You need to fire Tom.
Get yourself an animator who can work at least in 5 dimensions.
do you know anyone you can recommend?
@@upandatom Yeah, but he is hard to reach ...😉😉😅😅
@@ignorasmusYup, I tried finding him and somehow mysteriously teleported back to where I started
@ratvomit874 but were you upsidedown, back to front, inside out, or just a little twisted when you arrived? We need to know
@upandatom If you wanna try finding this guy, I heard from the locals his name is Jerry
Most thorough explanation I’ve seen of what flat means for shape of the universe. Thanks.
Me "what's the shape of the universe?"
Scientists: "We don't know, buuuuuut we know a girl who will make the most entertaining way to tell you that over about 20 minutes"
❤❤❤❤
Thanks for saving us the time
A Friend of a friend I know ….
Knows a young woman who can bend herself into any of these shapes. 🥰
....A "beautiful" girl who will make the most entertaining.......
Not so detail, but at least I can get some important points. Good teacher
@@nicknac1980 I wanted to write that but I was not sure if it would be considered inappropriate. One unfortunately has to be careful in this day and age with compliments...
"Your theory of a donut-shaped universe is intriguing, Homer. I may have to steal it." - Stephen Hawking to Homer Simpson in S10 Ep22 They Saved Lisa's Brain (1999)
Mmmmm.... Donut... 😂😂😂
Yeah i have thought of this episode too
Once again the Simpsons are prophets . Like their tapped into the collect consciousness. Omnipresent.
Edit. I donut remember leaving this comment!
8:30 I could not thank you more for this clarification! All videos mention flatness of the universe as if all viewers understand what is meant by flat.
13:21 OMG that completely explains all those Scooby Doo chase scenes! XD
4:20 hate to be pedantic but your photon path is wrong, it should curve in toward the sphere, not "pushed out". see me after class.
That's not pedantic, the photon just follows negative gravity
Lol, I should have checked the comments first. This irritated me so much I paused the video to immediately comment on it myself, then noticed you'd already pointed it out.
The photon at 4:20 is high and moves accordingly
@@x4rdas no the path of the photon should change but it doesn't. It's the same in and out.
@@userAndix It was shown with double curvature, when it should be a hyperbole with single curvature.
Great editing work on this video! I laughed several times at the (quasi rhetorical) question followed by snappy cutaway. Very playful, and it works perfectly with Jade's sparkling style of delivery.
there is a path through koningsburg that crosses all bridges only once; you just need to swim across a river once.
@@LiveWire937 or be a really good jumper
or travel to the next town and cross that bridge and then come back.
or run around the planet to come out on the other side of Koningsburg
that's the spirit!
@@Lensflare-85 Why running around the planet? Keep just your position and let the planet turn around...
To save everyone's time: No one's figured out the definitive answer yet.
Thank you so much!
Thank you sir!
I'm not against watching long format videos, but I've been burned so many times watching 20 min videos for NOTHING to be answered and only going over information I already know.
@@u235u235u235yup
@@u235u235u235 I feel like the detail and nuance in this video is good, though.
Thanks. The whole video is interesting, but clearly made just to upsell
Ah, yes, topology, the field of mathematics that can't distinguish a donut and a coffee mug, which makes breakfast rather more dangerous than normal.
I loved the jump scares.
Jade got every bit of tea out of my mug with them.
Impressive!
Hehehe
Except, there's nothing stopping you from making a donut shaped coffee mug or a coffee mug shaped donut. The shape is not inherently dangerous. The material is the danger.
Guess topology is better than we give it credit for.
@@Bli-k8m topology lets us see from the eyes of an alien god
No offence, but as a topologist i really hate to see people think about topology like that, topology is not about saying that "donut and a coffee mug are the same bc you turn one in to another" no, topology is about generalizing concept of continuity, compactness and other calculus stuff, which leads to things like toplogical spaces one of which is a torus(or if filled a donut) and yes, topology is about finding which spaces are same or more accurately homoemorphic bc then we can tell that some spaces have some properties bc it's "same" as the other one which we know it has, but it doesn't give a damn about real geometrical objects like a donut and a cup, it's like saying that geometry is field of mathematics which can construct a pentagon with a compass and a straightedge
@@anime_erotika585 I know that, anyone who knows anything about topology knows that, it's a joke. Have a donut!
I genuinely think this is, in all of my many years on RUclips, absolutely my most favorite channel. Thank you for never slowing down, and thank you for always making education so accessible! :)
As always, lovely video, Jade! Thanks a lot for making such fun videos that are so informative! Special shout out to your animator, Tom🥰
thank you for watching and supporting the channel :)
@@upandatomyou are so beautiful
@dixee6498 I hear you, but for reals, unless she's already a friend, keep it to yourself. And I know the fear of saying that to a friend, I know the pain of losing a friend for saying it... but I also know the joy of telling a friend who loved me back 😉... everyone in your life is important, but we all have our own thread in the weave, and eventually some one will leave, but don't stop weavin, and eventually you'll find your reason. ❤✌️
The diagram at 4:25 does not support the idea of a geodesic very well, since there would be no reason for the object(photon) to bend leftward and then return to its original heading. Rather, the interaction would cause a quadratic curve-overall, a deflection from its original heading. If light really acted like that, then you wouldn’t even realize that the light path was bent by the presence of the sun, which relies on the displacement of the position of the source.
Liked the gravitational lens image with the smiling face. :)
This is what I was gonna say.
The smiling gravitational lense. 😊
And here I thought it was a universal smiley
Smiling back at you!
As someone who has contemplated this very question for decades, I want to thank you for making this video. It's so refreshing to hear someone deal with this subject honestly. Every time I hear some famous scientist say, "well, we think the universe is flat because it looks flat," I want to pull my hair out. As this video illustrates, the appearance of flatness can be easily explained by the size of the whole relative to the portion you are able to measure. It baffles me that so many learned minds are unable to recognize the cognitive dissonance of believing that the universe is infinitely large and simultaneously believing that the portion we can measure is large enough to prove that. We maaaay one day be able to prove that the universe is a closed shape. But you can NEVER prove that it is flat.
Cosmology is famous for pulling "Scientific" Wild Ass Guesses out-the-ass.
Your passion is engrossing, and delivery explaining physics is first rate!
Thank you for your videos!
If the universe turns out to be doughnut shaped, I hope it is sour cream. Great crumb texture and tasty vanilla glaze is the best reality one could ask for.
The pause for ur answer after she asks a question makes me think we're about to go into a "I'm the map, I'm the map I'm the map" song😂
Lol. I'm sitting there trying my best to answer, thinking Steve didn't challenge me this hard
Great and gripping storytelling, and just the right amount of background to be neither confusing nor patronising.
You're back! Can't wait to watch this as soon as I get off work.
Same
I prefer to watch it at work 😅
If jade did not give my comment to a Heart then i will delete my comment as a protest.. 🤷♂.. Jade!!! ...
Where are uuuuu...
This is one of the few scientific videos that I can say I genuinely enjoyed! Great pace and magnificent delivery of an otherwise dense and tedious content. Great job!
4:22 That representation of the path of light is a bit absurd, isn't it? Shouldn't it look like an hyperbolic trajectory? If light is going dead center towards the CoM of the planet/star it won't get curved, it will just collide with it.If light behaved in the way shown. planets would be effectively transparent/invisible.
The path should be straight until it gets close to the mass where it gets effected by the gravity of the mass. That is where it is bent on a path that can be approximated by a hyperbola. The curve is always inward toward the mass and only when it is near the mass. It will not curve outward from the mass. After it gets farther away from the mass it will be going effectively straight again. The path would therefore be a straight line before the mass in a direction that off center of the mass. There will be bending near the mass and only towards the mass. Then effectively the path straightens out again after the mass.
Actually, she has a picture of the light bending around a mass on the general relativity plaque on the wall behind her. However, it looks like that plaque may be a bit off on the edges.
edit: let me add one more thing besides what I said below: the path of light around a spinning black hole can be complicated. Google: research gate Gravitational Lensing by Spinning Black Holes in Astrophysics, and in the Movie Interstellar. There are some diagrams there on it.
That was my thought too. I think the path of light should dip inwards towards the mass as it gets closer, rather than away as depicted.
Yeah, I don't understand why every science channel always portrays it wrong like that. The trajectories look basically like trajectories from an actual lens. Not these sudden bends away from the center of mass.
Yes, it's completely wrong.
This should be the top comment
Although the duration of this video was 18 minutes but it felt like 5 minutes. What a nice and simplified explanation of complex topics in a friendly manner. Great work mam.
Damn, I am here after a long time and your editing has improved so much :).
The goofy drawn characters had a certain charm
Really excellent exposition. Vivacious, articulate, fascinating.
18 seems like a large number of shapes I can't imagine and can't be shown to me, but which I could possibly live in 😢
She showed 3 2d analogies. Maybe the other 15 are rotations etc.
I can see the edges of a cube joining up to the other edge in a hyper torus ma y ways.
@@nosuchthing8I am one of the authors of the paper, yes this is correct they are (mostly) rotations
worry not friend, as locally, none of them matter 😅
SO good and so well put together and no expectations you'd cover everything but i'd like to point out that in terms of the CMB the "objects" represent actual sound waves moving through the medium of the universe at that time because we have a good sense of the density (it was really dance) at that moment that the universe became translucent enough to set light out on it's way, we can do fourier (and other ) analysis to find waves and calculate the size of a wave. that gives us a sense of the size an observed object "should" be so we can compare it
One must remember the Cosmic Microwave Background is not complete. What we see is merely that portion which was able to reach our detectors. The complete picture can be infinite.
It is impossible to be infinite, that means there was enough time for all the stars to go through heat death already, it had a beginning and that scares people bc of the implications.
@@WeAreGhuraba the universe couldn't care less about how people feel.
A big claim like that has to have a source so state your source
@@jamesharmon4994 oh the irony, my opinion is based on science, yours is wishful thinking.
@@jamesharmon4994 How about you actually trying refuting what I said. If the universe is infinite, whatever that means, how is it we can still see stars outside? Should there not have been enough time for them to all suffer heat death?
Great explanations! I felt like each subtopic could be expanded to make whole videos ^^
Also, your expressiveness and gentle voice make your videos pleasant to watch.
The biggest unanswered question in this video (that science has yet to acknowledge and is frankly concerning): how does the music at 18:25 slap so hard?
"Helios" by Lexica for anyone wondering. I spent ages sampling bit music on epidemicsound and then remembered Shazam exists
Time Mark 4:31 to 4:41 a smiley face in the Stars
There are some confusing inaccuracies here:
1) As later pointed out in the video, the curvature being too small to measure is not what prevents us from determining topology, as even perfectly flat geometry can have multiple different toplogies
2) The light trajectories on the flat torus are actually straight, they are not just geodesics (lines of minimal curvature) curved by the curvature of space itself. The curvature in the illustration comes from the visualization, it actually shows a curved torus, not a flat one. The flat torus is later visualized in the video with the square where you come back at the other end when walking out.
3) Switching from the curved torus to the flat torus *does* change fundemental geometry (from half-hyperbolic half-elliptical to euclidean). What is not changing is the *topology*
I think you're mixing up extrinsic and intrinsic curvature. A torus does not have intrinsic curvature, so light goes straight rather than following geodesics. But the path is still extrinsically curved (well, except when viewed from within the torus).
If you add intrinsic curvature to a torus, I believe you simply get a Klein bottle
Great example of incorrectly correcting someone. Can it, no name.
@@FunkyDexter A torus is never like a Klein bottle. The Klein bottle has only one surface but a torus has two (Inside/Outside).
@@Merilix2 yeah, turns out a donut does have intrinsic curvature I was wrong.
We need more Up and Atom in our lives. Thank you for making this stuff relatable with flair and fun.
1:15
Simple answer:
Lable the areas ABCD
A
||\
B-C
||/
D
Each area has a "state"; you're either "in" that area, or you're "out" (i/o).
You can only be "in" one area at a time.
Crossing a bridge changes the state of both areas it's attached to: i>o or o>i
The number of times an area's state changes equals the number of bridges it has.
B =4
A,C,D =3
If the state changes an odd number of times, the final state is opposite from the start.
If the state changes an even number of times, the final state is the same as the start.
If you start in B, you'll end in B:
B: i>i
However you'll also "end" in A, C, and D as well.
A,C,D: o>i
You can't start or end in B.
If you start in an odd number area, you'll "end" in the other 2.
i>o
o>i
o>i
So, NO, you can't cross all bridges only once.
B=5 ...
I think about the shape of the universe all the time it's actually one of the most complex questions I like to ponder. Thanks for sharing this incredible information.
Yay, a new Up and Atom video! This is me dropping everything to watch immediately
05:10 f
Before drawing a triangle, we must define geodesics first, because the sides of the triangle have to be geodesic.
Love your content and in particular your way of explaining confusing concepts! ❤
Jade you have truly found your joy and it shows. Excellent approach to the topic of spacetime topology.
I have a question on 8:18. How did they know the actual size of these spots?
I have the same question.
And knowing that the universe is expanding, it it even harder to determine how large they were when the light was generated.
@@renedekker9806 Let's see if she replies. She usually doesn't cover all this in the video as the answers are highly technical.
Telescopes can measure the size by looking at them
@@liveshkumar7322 Wait what? What exactly are those spots that could be measured by a telescope?
@@liveshkumar7322 _"Telescopes can measure the size by looking at them"_ - I suggest you watch the video first, before commenting.
The age of the universe is a huge determining factor. Light from the boundaries of our universe likely has not had enough time to reach us.
The entirety of the observable universe. Not the entirety of the whole universe. The flatness of the observable universe, could also be interpreted as a local flatness that doesn't necessary apply to the rest of the universe. Unfortunately we'll never know.
It's worse than that. The mind examine the mind itself, and can't see out of it. I call it the "dog principle". Science is based on the assumption, that since we can outsmart a dog 7 times out of 10, therefore we can understand the universe. It's all based on a dog and nothing else.
Yea, we can only see a portion of what exists bc the observable universe is limited by the speed of light and the age of the universe
@@AncientWildTV Also, there is one thing, greatly overlooked. That's saying, the ants look up the sky and see nothing. Dogs are howling the moon. We humans, we see and know everything, or at least having the capacity of. This logical jump bothers me. Measuring what there is to the dog, I find it suspicious. I mean, making a postulate of any being slightly more intelligent than a dog, is nothing short of perfection, sounds ridiculous to me
I mean, people can look up the sky, make observations, it's fine. But stop barking!
@@szolanek yeah like what if the way we interpret the universe is just as limited as the perceptions of a dog or an ant
The answer is 42 - You just can't simultaneously know what the question is (within the same universe) ;-)
As always, Jade's videos are overflowing with this wonderful positivity and humor while still managing to explain complex ideas. I wish I could bring clones of Jade into every school on the planet as their respective physics teacher, heck I even wish I could turn back time and have a clone of Jade as my own teacher. But the clones would definitively need to have the sound effects from these videos as well, flipping the hair should make that sound in real life too! 💜
Love the channel! I hope it continues to grow!
thank you for your support!
@ 5:47 - This silly cut earned you both my up=thumb as well as a new subscriber. Love it!
Awesome vid! Super informative, interesting, and hilarious. Thanks a bunch! 🚀🌌
thanks for watching and supporting the channel :)
@@upandatom You do a great job! The camera cuts in this one had me laughing, the intensity 😁
Omg I got flashbacks from the part at 11:09 about seeing your back. Awesome! :)
12:55 i swear i remember a "game" that simulates this where you are in a spaceship and there is an earth that repeats depending on the topology of the universe you chose, it was so trippy
Edit: it's curved spaces from geometry games :D
Are you talking early 90's ish? I have a vague memory of a spaceship game that seemed like it was always repeating as well. I don't remember any other details though.
@@davidfoster5561 no, its a computer game but i found it!
its called Curved Spaces on the Geometry Games site, Topology and Geometry Software
it has flat, hyperbolic and spherical universes all ready for you to fly in
@@davidfoster5561 heck my comment got deleted because I posted a link 😭 but I found it, search for "curved spaces geometry games"
@@davidfoster5561 google "geometry games curved spaces"
@@davidfoster5561 naw but i found it
14:26 Every preschool show ever's forever pause of silence(Dora the Explorer esspesialy):
And now we all understand the ending to Interstellar.
Great video. That’s the clearest and most thought provoking of anything that I’ve seen in the subject. Many thanks indeed.
I can confirm, we do indeed live in a flat surface Klein Bottle universe
10:00
How can you confirm
Dude just loves klein bottles
Well I'm glad that's settled
@@robertlee8519perhaps, he has just "un-bottled" himself 🤔
@@alexbenzie6585or emptied one too many just before commenting.
Excellent physics , quantum explanations Jade
Thank you for your video. Awesome, as usual. It'd be great to reintroduce your cartoony characters in one of your future vids.
Clever camera angle switches! Also, very clear explanations!
Has Jade always been this Dora-ish?
Dude, I was gonna ask the same thing, this is Dora the Explorer does cosmology all of a sudden
Even the backpack!
The use of "handy-dandy" in addition to the pauses makes it seem intentional.
I was thinking the exact same thing.
Nope. As someone who's been back after a long time, the Dora-ness is quite new
I love the whoosh and you speak to a different camera angle. So fun! Your videos are great and I get excited to learn 100 things every time I watch one.
i'm neither an astronomer nor an astrologist...
but i certainly wouldn't wanna live inside a Taurus >.<
unless Ford gives me one for free
You have my new favorite RUclips channel name! And your delivery is delightful. Huzzah! You have a new subscriber.
If the torus is large enough, the universe would expand faster than the speed of light - meaning the light from your backside would never reach your eyes.
As usual. I love your wonderments and analogies of presenting the information. Thank you again for a GREAT video.
Great video as always, but this new style of presenting material feels a bit like watching Dora the Explorer (14:23 for example)
lmao
The possible topology of the universe on very *small* scales is interesting too - it could be responsible for the fundamental quantum fields that give our reality the form it has.
Caution Jumpscare at 10:15
😂😂😂😂
You're back!! Missed you smart Aussie girl!
Cheers from the Pacific West Coast of Canada.
Imagine a universe where walking in one direction brings you back to where you started, but everything is mirrored left to right. To you it would look like a flipped version of your world. But you couldn’t survive because of the chirality of molecules (twist direction of molecules changes their effects). Most things you'd eat or breathe would likely kill you... You'd need to take another round-trip fast to stay alive!
At least we'd be able to detect right-handed neutrinos for once.
I don't think there would be a problem because of the chirality of molecules: all molecules would be reflected, so the position of direction-sensitive molecules relative to others would not be altered.
@@jaimecastano8745 not the molecules in your body, you would have brought them around the trip with you. It’s as if you would have brought your house key with you, it wouldn’t fit the lock in the (to you) mirrored world.
@@qb0816 the molecules you rely on for survival-like amino acids and sugars-would likely behave completely differently, potentially rendering them toxic.
@@jaimecastano8745this is correct. Things look flipped to an outside observer but after just "normal" to people there
Just discovered this channel. Refreshing to hear a familiar Australian accent with such knowledge and understanding of maths and physics.
'Elon Musk promised' is the modern equivalent of "the cheque's in the mail"
4:14 Looks like a light-repelling star.
A white hole?
Space is a Pringle…that’s yummy!
Once you pop, you just can't stop!
pringles are overrated. There, i said it
@@fetB they're just fried reconstituted powdered instant potatoes.
Not yummy when you draw on them with a Sharpie. Stupid parallel lines 😢
Seriously?! I love this girl! Not just she's pretty, but she is truly smart! She is something I'd like as a life partner! Granted, I'm way too old for that young lady... but one can dream, right?! Can I give more than one upvote to her, please?!
The universe may not be flat, it may just be curved on a scale we can not yet (Or possibly, ever) detect.
Yes, but hypotheticals like that have no practical use.
For those of you looking, Euler found that it was impossible to cross each bridge in Königsberg once and only once.
0:30 speak for yourself!
Kek
😂😂😂😂
Lel
Great album from Imogen Heap
Dora explores the cosmos! First video I've watched of yours and it was engaging, informative, and fun. Definitely watching more!
Is the order of the pictures on the wall behind you a test? Because it keeps changing. Just like the position and rotation of the table and the globe. I like the pictures. It is so nerdy to have entropy, GR, Math and QM on the wall.
Btw the true shape of Elon Musk is undistorted fascism.
wow musk derangement syndrome; thanks for sharing that thought on a totally unrelated video & i hope you get the help you need
I don't feel smart enough to say for certain, but the visual of the background pictures feel like they relate to the topic. As for the globe, it was directly used at one point, so the room was rearranged a couple of times and there were multiple film cuts for editing. I don't think it was intentional. Kinda the same with the pics, I think they changed them after the first one or two cuts, but they're pretty consistent afterwards. The shape of Musk is that of an entitled child of wealth stumbling through the world.
4:21 Welcome back. Thanks for the video! (I think the light in this diagram would not resume in the same original direction once past the mass.)
I have a couple of questions:
- can you really bend the cylinder into the torus? The 'inside' of the torus is a shorter path than the outside so you have to distort the cylinder.
- how do cosmologists tell the 'actual' size of the cool or warm spots in the CMB? Wouldn't all methods of measure be affected by the topology of the universe?
In topology there is an operation that welds edges of a shape together. So in your example, we would weld the two circles of the cylinder together. That doesn't distort the cylinder. It retains any surface curvature.
@@mrpocock Thanks, but that doesn't really address the issue.
See, a cylinder has the 2 circles you mention but to turn it into a toroid the 2 SIDES have to bend. 1 bends into a small circle & the other bends into a large circle. So a (say) 2" cylinder long enough to bend into a (say) torus with a 2" hole, the small side will be ~6.28" but the long side will be 18.84. i.e. the donut hole has diam 2 x 3.14 while the external circle is 6 x 3.14. (2" hole + 2 x 2" diam of cylinder.
So I can't see how a cylinder can transform into a torus without 'magic' to alter the dimensions.
Note: I do understand in topology one can stretch & distort however one wishes, but the discussion is about possible reality, not maths concepts. Can actual space be compressed or stretched to accommodate such things?
Or do we accept it as just more fantasy from Physics done by Maths?
@@markmcd2780 the stretching and distortion is an artifact of measuring distances and angles in 3d space, not in the 2d space defined by the cylinder surface. Before deforming it, you could grid out the surface of the cylinder. Then bend and glue it onto the torus. Then continue to measure distance on the torus using that (now distorted) mesh. It entirely depends upon if you are bound to the surface, with that defining your coordinates, or if you are unbound. We're bound to the universe, so we see geometry defined by its 3d surface.
@@mrpocock I'll be honest & say I have no idea what any of that means. Is it mystical catechism to invoke the sub-ethereal trans-universe? A magical formula for making 5 = 1.2?
Seems to me the 'mesh' is going to be wildly distorted to fit on the cylinder. Maybe we could use it as an FTL drive? take a cylinder of space, bend it into a tor5us then move to the inner side to travel then back out to the destination?
🤫
@@KastorFlux 😆All those comedians out of work & you're looking for a job...😄
But hey, near as I can tell, until you leave the esoteric world of theoretical topology, anything might be possible. The question is, what could be real.
I'd be curious just what kind of a Big Bang could produce a toroid universe - or anything except an expanding sphere. Near as I can tell, anything else requires something OUTSIDE the universe to shape it.
some of the best explanations of this stuff that ive come across so far
Really fun video! The diagram at 4:21 give the wrong impression, though - that light ray was already heading straight toward the massive object. It would have had to be travelling on either side to then follow the curvature (like an Einstein Cross).
Fascinating commentary! Thanks for the video 😊
Very informative and effective video. Topology can be quite confusing but you pretty much summed it up.
The way you freeze before answering rhetorical questions is a bit creepy yet strangely captivating. Subscribed ;p
Excellent, informative AND enjoyable!
The Bill Nye quick camera shift at 5:45 had me laughing, thanks for that nice flashback.
3:46 ...on relatively small scales like on the scale of stars or black holes, or even CLUSTERS OF GALAXIES...
It's always a treat to see a new video from you. Very intriguing video, I must say. It left me pondering parallaxes and the CMB.
Our planet has moved 435.6 billion kilometers since the discovery of the CMB. It would seem that we could get some level of parallax on the CMB if we compare the earliest images to the most modern ones. Surely that would be informative to this subject
I've always wondered why the seemingly arbitrary rules of topology were what they are. It being a descendant of graph theory makes it make so much more sense!
Very nicely explained!!! 👍 First time, I actually understood this universe is flat stuff.
What a great video - as always ... Learnt a lot and enjoyed every second! Thank you!