How Many Dimensions Can You See?

do we see the world in 2d or 3d they thinking well 3d but then you're thinking well why is there a ten minute video in this question if it's that simple so I could just tell you but I think I'm going to show you let's take a trip to a lower dimensional world and see if we can work things out from there [Music] my land is a one dimensional world but only lines exist there's only left and right up down back and forth do not exist the citizens of line land are themselves lines as nothing else can exist in a one-dimensional world now let's take a look at an interaction between two citizens of line land from the perspective of the purple line the blue line looks like a zero dimensional point the purple line can only see the front of the blue line and even if it did somehow have see-through vision it would just see a series of points it can't even tell how far away the blue line is as points don't expand or shrink in size and it would be the same from the blue lines perspective the blue line would say the purple line as a point so in a one dimensional world the citizens say in zero dimensions or points now let's move up a dimension plant land is a two dimensional world where everything is perfectly flat there is left and right back and forth but no up-and-down the citizens of flatland have no understanding of up and down and is simply not capable of understanding it as it does not exist in their world only two-dimensional objects like circles and squares exists in flatland they have width and length but no height now let's take a look at an interaction between some of the citizens of flatland [Music] from the perspective of the circle both the square and the triangle look exactly the same like one-dimensional lines the circle can only see what is directly in front of her so she cannot see that one of the objects is a square and one is a triangle because that would require her to see behind the front of the shapes or have two-dimensional vision in fact two the square in the triangle the circle also looks like a one-dimensional line and the only reason they know that they are speaking to her is because they know that she likes to wear purple so in a two-dimensional world the citizen see in one dimension so in a 1d world they see in zero D in a 2d world they see in 1d are you starting to see a pattern it follows that in a 3d world we see in 2d imagine you in our 3d world and you see a cube in front of you from your perspective you are seeing only a two-dimensional square the face of the cube you can see the length and width but not the depth this could be a rectangular prism and you wouldn't know so why is this surprising I mean why do we insure it if we think that we see in three dimensions well let's try rotating the cube screw it let's just move it to a real 3d space so this is our 3-dimensional cube in our three-dimensional world and you can see that it is indeed a three dimensional cube but if I hold it up like this you can just see a two-dimensional square you can see width length but no depth and now if I rotate the cube you are still seeing a two-dimensional shape you can see with like but no debts so why do you get the feeling that you can see depth I mean you can tell that this edge is closer than this one if I move the rubik's cube forward and backward you can tell that it's coming closer to you and further away so if you can't see in 3d why do you think you can see in 3d your brain is pretty incredible we live in a 3d world and it makes sense for us to perceive our world as accurately as it is so this is why your brain has evolved a bunch of tricks to help you perceive this 2d image as 3d take this photograph for example this is a typical day-to-day image you've likely seen before you know it's a 2d image because you're seeing it on a 2d screen but your brain is using so many techniques just in this one image so that you can map this into a 3d space and that's just in a still photograph there are many more tricks involved when you are seeing it in real life or when movement is involved so what would three-dimensional vision look like I mean let's extend this pattern let's imagine that there's a four-dimensional world and they can see into our three-dimensional world what would they see well let's go back to 2-dimensional flatland for a sec the square has gotten tired of socializing and decides to go home now the hexagon is walking past her visit but he's arrived late and he doesn't know if the square has gone to bed because you can't see inside the house he decides to play it safe and come back tomorrow so a 2-dimensional citizen can't see into another 2-dimensional citizens home because all they're seeing is a wall us three-dimensional beams on the other hand can easily see that the square is wide awake as from our perspective we can see into his home so if a four-dimensional creature was looking into our world he'd be able to see into all of our homes he'd see every corner of every room through the roof through all of the walls he'd be able to see the first second third story all at the same time from every perspective he'd be able to see into this box without ever having to open it there's nothing in here so why can't we see in 3d I mean is there some kind of fundamental law well yes one of the biggies of quantum physics is that all photons are identical they're all exactly the same so this means you can't tell where anyone came from if one point from your mom or one came from the they're all exactly the same they simply don't carry that information but what if we did take this hypothetical example if you have two glowing objects in front of you but the one further away is glowing brighter than the one closer to you this is a situation where your brains tricks don't work your brain can't distinguish the two it looks as if both objects at the same distance away this is why we can't tell how far away stars are simply by looking at them our eyes can't tell where the photons are coming from now imagine we're in an alternate universe where the laws of physics are the same except that photons carry the information of where they came from this situation would no longer fool you you're getting the correct information in the X Y and Zed direction with lengths and depths this is no longer just your brain perceiving depth the information is there and it's accurate you're receiving information in all three dimensions so this could be said to be 3d vision of course the third axis information is being conveyed differently to the X and y and this isn't health 4d beams with same 3d but you are receiving current information in all three dimensions without your brain having to process anything but that's all just speculation I mean in this universe light doesn't behave that way but what about sound some animals like bats use echolocation or ultrasound waves to map their surroundings using echoes to locate objects they measure the time delay between when they emit a sound and when it freezes better there is so they can tell exactly how far away an object is by counting a time delay bats and other animals that use echolocation wouldn't be fooled by this test because the information receiving isn't dependent on any kind of brain processing so in this way balanced whales and a few other animals can map our 3d world more accurately than weekend and respect our 3d vision so to sum up we live in a 3d world but we see in 2d but now brain tricks us into thinking that we see in 3d but some situations can fool our brains which wouldn't happen if we lived in an alternate universe where the laws of physics were different in that photons knew where they were coming from I hope that answers the question that's it guys thanks so much for watching if you like this video or thought it was interesting give it a thumbs up I'd love to have you subscribe I post a video about every second week if you have a cool idea for a video or you have any questions about this video just leave me a comment below and I'll get back to you and add me on Facebook and Instagram I post like funny things about scientists or sometimes like quotes by scientists or random pretty things so yeah I've put all the links below in the description I've also put the link to the Wikipedia article on depth perception if you wanted to read more about your brain's tricks yeah that's it see you next time bye how to describe the photoelectric effect the quantum nature of light 1/n Stein a Nobel Prize spawned a whole new field of physics revolutionize the way we view the entire physical world yeah it's a pretty big deal

Channel: Up and Atom

Views: 148,173

Keywords: FLATLAND: How Many Dimensions Can You See?, flatland: a romance of many dimensions, dimension, Flatland, How Many Dimensions Can You See?, up and atom, do human eyes see 2D or 3D, flatland, Up and Atom, 2 dimensional vision, 3D vision, physics, dimensions, perception, depth perception, 3D, 2D, three dimensions, three dimensional vision, fourth dimension, 4D, quantum physics, light, physics video, physics tutorial, video on perception, dimensions tutorial

Id: cwWbSVzAFLQ

Length: 9min 24sec (564 seconds)

Published: Wed Oct 12 2016