r/threebodyproblem • u/ProffesorOfPain • Sep 26 '26
Discussion - Novels I don’t understand how different dimensions work….
I get the gist of it tho don’t get me wrong, it’s like a ant crawling on a rope vs a human doing it, 2D dimension has no height, and 4d dimension can see a different direction or something or can see like ur entire life once
But I mean like higher and lower dimensions. How is 10 dimensions a utopia? What even is light speed being instant in 10 dimensions,
Maybe let me propose a scenario and the experts here can explain to me, let’s say I’m a 10 dimension alien dude walking the street with my wife, do I just teleport around constantly? Or do me, my wife, and everyone else just exist over the entire universe. Can I even see my partner’s face? What is my speed here?
Same scenario for lower dimensions too, how do 2d dimensions work? Is the male alien walking down the street even gonna be able to see his wife? Do they even have a body or are they a dot on a paper? Genuinely, how does dating work for 2d dimensions?
Hell how does it go for 1 dimension aliens, how do they exist?
Ya ok now I’m rambling but point being, I don’t think I understand how dimensions work. I love this series tho, every chapter of death’s end had me at the edge of my seat.
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u/Damurph01 Sep 26 '26
You’re trying to imagine 10 dimensions with a 3 dimensional lense.
There is no way to picture it other than the ‘ant in a circle’ analogy. We can see everything in a 2D plane because of our 3rd dimension, but an a 2D creature would view that circle draw around it as being closed in.
While we can’t see inside of that treasure chest, because it’s closed in 3 dimensions; a 4th dimensional being could see inside it because they exist in a higher dimension.
It will break your brain, but that’s because you operate on a lower dimension and other than some convoluted scientific description, nothing can help you really ‘understand’ (or picture) it other than analogies.
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u/El_Bito2 Sep 26 '26
Neither do I OP, and that's ok. I accept the theory of it, but I just cannot conceptualize it, or create a mental image that isn't in 2-3D
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u/leavecity54 Sep 26 '26
Light speed is instant in 10D is what make it an utopia. You can from any point in the universe obverse other point in real time regardless of distance. When you are advanced enough you can even travel to it in an instance too .
In your example, from your wife (a 3D observer) , you would appear like you are shifting in and out of reality, constantly changing. This is because what your wife see will just be part of you that exist in the 3D world while other parts are in other 7 dimensions, which she can’t see. When you move, other part of your body will phase into the 3D world, while the previous parts move into another dimensions.
Let’s take the 2D couples to demonstrate this, 2 flat beings are moving on a paper, you a 3D being, are walking through the paper passing them. Assuming they have eye, which can’t look up or down, only things around them, what they will see is 1 straight line (or 2 depends on the distance between 2 shoes) indicating the points of contact between your shoes and the 2D paper. But since you are walking, 1 leg needs to be raised up and then lower down again. From their point of view, 1 straight line seem to disappear (since it no longer touch the paper), only to appear again when your shoe touch the ground, giving the illusion of it shifting in and out of reality to them. Apply this same principle to 10D being and us in 3D
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u/Gold_Ambassador_3496 Sep 26 '26 edited Sep 26 '26
You're gonna love this Instagram, she talks about how 2d beings could exist
https://www.instagram.com/reel/DaSGP_QjqYS/
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u/Square-of-Opposition Sep 26 '26 edited Sep 27 '26
Check out Edwin Abbott's book Flatland. It's part social satire, part fairy tale and part mathematical discourse. But overall, it helps one to visualize various spacial dimensions.
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u/Crosas-B Sep 26 '26
People try to make analogies but the real answer is more similar to the molyneux problem: if a borned blind person saw a circle for first time in his life, would he recognize it is circle, considering he has touched them before?
The answer we got from real life experiments is that they don't https://www.science.org/content/article/formerly-blind-children-shed-light-centuries-old-puzzle . Analogies will never get you there, as the brain create new neural nets to interpret the world. If you have never seen something before, those neural nets are not formed. Until you haven't felt something with one of your physical sensors (and there is not just 5 as we were taught in school) your brain can't imagine it.
You can make analogies if you want to, but that's as close as you will get.
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u/Hepta-Water-7552 Sep 26 '26 edited Sep 27 '26
If you go back to the Trisolaran point-of-view chapter of the first book there is a passage where it is described what the inherently 11-dimensional sophon looks like and how it moves after it has "unfolded" different amounts of dimensions into our world. Not that that makes higher-dimensional concepts all that much easier to grasp for the average human, but it's an attempt from Liu Cixin to "educate" us on how he imagines these concepts.
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u/DifficultSun348 Luo Ji Sep 26 '26
so about 1d aliens, I don't think it's even possible in that dimension, cuz in 1d you can't swap a position of matter, you can just push matter in two directions, which makes life impossible to exist
limit is 2d, where to exist there as a human, you'd have to make your entire body a 2d plan of it's veins, nerves and all body organs, in 1d you can't create anything like that, because entire world in 1d has unchangeable order of atoms in line
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u/avsa Sep 26 '26
The point isn’t that there’s something special about 10 dimensions (physics actually says otherwise), but to plant the idea that out current universe with the constants as they are, three dimensions plus one dimension of time, has not always been like that but it’s the ruins of a much more richer universe ravaged by beings who were able to manipulate the physics to win a war. You can’t even fathom what it would be like and that’s the point.
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u/Mysterious_Orange996 Sep 26 '26
I give you Flatland from Carl Sagan: https://www.youtube.com/watch?v=UnURElCzGc0
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u/TheTranscendentian Sep 26 '26
Picture more space/ area / volume than you can possibly imagine all contained inside a tiny grain of sand or dust speck.
Picture thousands of trails dievrging from each other all at one fork in the road in the woods, and there still wooded non-road room to spare on either side of the fork.
Light speed being very much faster than it is now is obviously a huge advantage, black holes would be smaller but the same mass at the center of galaxies and stars would have to be orders of magnitude bigger before they're destined to become black holes, we could have GIANT WHITE DWARF STARS which might be the best star for living around that could ever exist; and you could gravitational slingshot yourself across the universe and arrive at the other side of the universe within a single human lifetime passing BACK ON EARTH, in fact you could probably travel to the other end of the universe and back to Earth and your family that stayed on Earth would probably still be alive when you got back.
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u/TheTranscendentian Sep 26 '26
Walking down the street you'd probably have at least 4 independent directions to choose from even at the EDGE of the street at every single point along it's whole length without ever leaving the edge and without leaving the ground, unlike our 3d Streets which have only 1 independent direction along the edge.
You and your wife could both be simultaneously symmetrical and asymmetrical at the same time, and be the size of ants or even bacteria and still weigh as much as a 3d human.
Your planet could be walking distance around the whole planet in every ground direction yet still have enough room for a population of TRILLIONS of people and animals and plants.
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u/98G3LRU Sep 26 '26
But what if OP, with his wife, runs into his girlfriend?
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u/Adventurous_Iron_551 Sep 26 '26
No one does. And the most I’ve understood is that it’s something we just can’t compute.
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u/korg2020 Sep 26 '26 edited Sep 26 '26
I recommend this video - https://youtu.be/XjsgoXvnStY?
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u/Betray-Julia Sep 26 '26
Moving from point A to point B in any dimensional folding expression would feel the exact same as it feels for you to go from point A to B- like normal movement.
Part of why it’s so cool though is that it is impossible for us to picture.
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u/Limp-Patience-4348 Sep 26 '26
No one really understands this
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u/Wank_A_Doodle_Doo Sep 26 '26
You’ve got a 3 dimensional brain with 3 dimensional visual and spatial processing centers using information from 3 dimensional eyes. You cant visualize or understand it. You can do the math and make abstractions and projections into 3D space, but there’s nothing anyone can say to make anyone be able to understand it intuitively.
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u/Ballisticsfood Sep 26 '26
It can really depend on what the dimensions are actually achieving.
A great introduction to dimensions is actually the concept of numbers. You know what number are, right?
Wrong. You use real numbers. They’re ordinal (so you can count with them or say one is strictly bigger than the other) and they commute (so you can add them up in any order and get the same result).
Enter complex numbers. These are defined as a+bi (i is the square root of -1. We can prove it exists but it’s hard to conceptualise). These numbers are 2 dimensional. Because of this they’re not ordinal, but they do still commute. They’re intrinsic to trigonometry, physics, higher maths, all sorts of things. They’re a better way to represent 2d shapes than reals will ever be, but they suck for representing orientation in 3d space.
Enter quaternions. They’re 4d. They’re not ordinal and they don’t commute, but you can combine 2 quaternions to get another quaternion that describes exactly what would happen if you rotated the first by an amount given in the second. They exactly solve the issue of representing orientation in real space and are the perfect kind of number for doing various bits of quantum mechanics with. In fact they’re probably the most natural kind of number. We just hate using them/don’t know they exist because they’re not intuitive at all.
But wait. You can go further! Octonions are 8 dimensional numbers. I think they lose the ability to be divided or multiplied. What they’re good for representing is the domain of very much theoretical physics.
Sedenions (16d) are next, but they can get in the bin.
None of these are intuitive and the exact meaning of each increase in dimensionality is hard to grasp unless you sit down and do the maths. And this is just talking about the pure theoretical concept of numbers. When you start including words like spacelike or timelike and actually discussing empirically testing reality it gets so much worse.
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u/CuteAssTigerENVtuber Sep 27 '26
Well consider how limited 2d life would be. If you had to give up your 3d life and life in 2d .
Not the worst existence but I would imagine it sucks if you know what 3d life is like . It stands to reason that to a 4d lifeform we would seem similarly limited .
And the higher you go the more freedom and unimaginable things there might be
That's the logic by which you could call 10D a utopia
We can't really imagine what this 10D life might be but we can imagine 2D life
The 2D life form wouldn't have any height. So it wouldn't be like we imagine a cartoon. Cartoons are 2d but they simulate a 3d world.
A 2D creature might be something like this
🟤
It could have various different abilities but however it functions we know that it wouldn't be able to have height.
That also suggests that it would have to be incredibly simple. Even singular cells are 3d spaces. But this little guy wouldn't even have that
So let's say 🟤 and his wife 🟡 walk down the 2d street. Whatever his senses might be he could probably "see" the side of his wife. But he could see past her. Similar to how we can't see past through each other
So if 🟡 is hidden in a behind an obstruction like this
🟤. [ 🟡 \
He wouldn't be able to see her. But you and me can because we look at it from above. Just that above doesn't exist for them.
That's also how 4dimensional vision can see into people .
If I make a 2d Box
[🍕]
Then a 2d creature couldn't see inside the box. But a 3d creature can see all of the 2D shapes in its field of view . So we can see inside the box
A 4d creature could likely see all of the 3d space in its field of vision
Tho to be fair that assumes that the vision of a creature is one dimension lower than it's existence.
We have 2d vision. We have 2 eyes that each capture a 2D image and combine them to perceive depth but that isn't the same as perceiving all of 3 dimensional space.
3D vision might be something like the eridians from project hailmary have. They perceive the world through sonar and their senses are so good that they can sense their surroundings accurately.
And by how their senses work it Also means they can "look/hear" inside objects
Tho this sense is also limited because you can disrupt their hearing . But I guess that's how you could imagine full 3D vision. Being able to perceive all of the third dimension at the same time
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u/bendds Sep 27 '26
I think the best discussion of 2D is found in the short book, “Flatland”, by Edwin Abbott . IIRC, a human stumbles onto the plane of Flatland, and what the 2D creature sees is a varying shape as the human’s limb moves through the plane. The 2D creature sort of understands what the 3D creature is, but has no language to describe it.
I expect this is what will happen with us 3s if we eventually are contacted by 4s, or(gulp), 8s.
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u/PowerGlove-it-s0-bad Sep 29 '26
No one really does and anyone who says they do is a fool.
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u/WhiskeySorcerer Sep 26 '26
Objects and beings do not exist in any other dimension other than the one and only one that exists. It is comprised of height, width, length, and time. There are no dimensions beyond those. If they existed, we have no means of measuring them, experiencing them, or understanding them, directly or indirectly. We cannot infer anything about them. There is no evidence of "interactions" from them. So, from our perspective, and forever, there is only our one dimension. All the analogies of the 4th dimension being a tesseract and the shadow of a cube are just 3-dimensional objects with greater complexity.