Submitted by Supastash t3_10okt5t in explainlikeimfive
A 2 dimension picture can’t imagine a 3 dimensional world but it exists. And 4th dimension exists but we can’t see it .what does this mean ? I’m I on a piece of paper per say and there’s another world we can’t explore even though we walk though out it ?
We don't know there's no 4th spatial dimension, we just know that either we can't access it or it's rolled up really tightly.
look at the shadow your hand makes on the wall:
that's a 2-dimensional representation of your hand
as seen by a 3-D person
now look at your hand directly:
that's the 3-dimensional shadow of your hand
as a 4-D person would see it
Unfortunately your question is based on a faulty understanding.
As far as we know, scientifically, the 4th spatial dimension has NOT been proven to exist. The thought experiment that you describe is based on a supposition / assumption of what it would be like IF a 4th spatial dimension DOES exist, but is not itself proof of the dimension existing.
In fact, that very thought experiment answers your question - a 2 dimensional being cannot percieve a 3 dimensional shape more than 'slices of it' as it passes through their lives. A 3D being will similarly not be able to percieve a 4D object except for 'slices of it' as it passes through time in our plane of existance. We cannot see something that we cannot see.
However, why has the 4th Dimension not yet been proven? Well, if it does exist, tl;dr then we would be able to see these 'slices' occuring. Scientists have noted that in tests and particle tests, no matter from our world 'leaks' into any other dimension.
For a much longer but much more detailed explanation, you can read up here:
Well, classically the fourth dimension is time (height, depth, width, and time would be how you plot where something is in space and time). Which you can't see time, so there's that.
But on the general nature of perception, you can only see within a narrow bandwidth of light, and there are colors outside your perception (like ultraviolet and infrared as a very immediately outside the band examples). You can't see radio waves, radiation, etc. The same is true for each other sense you have. Thus, it's "possible" an entire world that we can't perceive exists.
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Dimension is a broad mathematical term, that very loosely means "ingredient".
The numbers that you are used to 1,2,3,4 etc have one ingredient. That ingredient being "1". We call these "1 Dimensional". Such numbers are ussually useful, but sometimes they are not able to capture the reality of a situation.
You can count cookies with 1D numbers, but when you want to describe WHERE you are, you need three ingredients (UP, RIGHT and FORWARD). Hence we live in a "3D world".
You might use more complicated numbers to describe your situation in more detail. Perhaps you want to know where you are but also how hot it is, which would require 4 ingredients (4 dimensions).
Physicists generally are often interested in WHERE and WHEN, because they are specifically interested in movement. The physics of a situation that doesn't change does not require a professional after all. Hence, (for their purposes), 4 ingredients are needed to describe a situation.
Sometimes physicists will use 6 ingredients: 3 for where (position) and 3 for where will you be (velocity).
Sometimes they are interested in a situation where some ingredients don't matter. In simple harmonic motion, there is a simple repetition, so only one ingredient is needed to describe the where and another for when.
By changing which number systems are used for the mathematics, we can make calculations easier or clearer or link two problems that seem unrelated at first.
Sci fi have often (incorrectly) used the word dimension as a stand in for "universe" or "world". And this has led many snake oil salesman to making videos that claim the "fourth dimension" or "fifth dimension" to be some mystical hidden place.
Dimensions don't have an order so calling anything the 4th dimension is misleading in and of itself, never mind the weird pseudo science that the term is used to push.
Cake could be said to be 3 dimensional. Any basic cake is some combination of flour, egg and milk and so we could label each cake with a 3D number and discuss which 3D numbers correspond to nice cakes and which correspond to failed cakes. For example (0,0,1), or a cake containing only milk, would be a failed cake.
If I then came along and showed you a chocolate cake, suddenly I'm adding a "fourth ingredient": chocolate. But there's nothing mystical about chocolate and it's only "4th" in the sense that you weren't considering it beforehand and now you are.
There’s a lot of the world you can’t fully see as it is, nevermind 4D. Human eyeballs are terrible imaging devices. Very bad, stupid design. We can’t even see all the colors a mantis shrimp can see.
A dimension is really just a fancy name for a direction. The 4^th dimension is time. Although if you are talking about a literal 4^th dimension, hypothetically the string theory predicts 26 dimensions with 22 of them being hidden at the quantum level.
When it comes to a fourth spatial dimension, we have yet to experimentally demonstrate it actually exists. Some theoretical models of physics (such as String Theory) mathematically represent more than three spatial dimensions. That doesn’t necessarily mean though that those dimensions exist in a way that a human, or any complex object or organism would be able to interact with.
When talking about higher dimensions it could be that only sub atomic particles are able to move through or interact with them, that they may be folded in on themselves having collapsed after the beginning of the universe or only exist in universes different to our own.
There is no hard and fast answer to your question beyond saying that if a fourth spatial dimension does exist, it may be physically impossible for you to interact with it in any way that would be meaningful to you.
Could be a limitation of our brains, and we could be able to teach around it.
We need to think better in 3d and up dimensions
If I had a kid I'd have him play 3d and 4d and 5d (must be possible, one day) tic-tac-toe
You can make tic tac toe as many dimensions as you'd like. It's easy enough to do on paper. 4D tic tac toe is only 27 squares. 5D is an overwhelming 81, but there's nothing stopping you from drawing 81 squares on a piece of paper.
The issue is that tic tac toe becomes a worse game the more dimensions that you add. The entire point of the game (if there even is a point) is to block the other person from winning.
The more directions that lines can point in the more pointless it becomes to try and block your opponent.
so I'm getting downvoted for not being a genius?
hmmmm
I wonder if there's any game that is fun in 5D
You're being down voted for answering an ELI5 on a topic you know zilch about.
And I'm not sure why you're replying to my comment with this sarcasm after I genuinely engaged with your comment and explained what you were pondering
I'm replying because I am in fact a genius
I'm the guy who came up with the political solution of disenfranchising all men
I'm the guy who came up with the idea to teach all babies sign language
I'm the guy who first discovered that quantum entanglement does in fact communicate information: it guarantees that randomness can be the same all over the universe at the same time
I think that this discussion could be more polite that's all
shinysnake727 t1_j6f8s87 wrote
A fourth dimension doesn’t exist in the way you’re imagining it.
Forward and back is 1 dimensional like a line, adding left and right make it 2 dimensional, and adding up and down makes it 3 dimensional. There isn’t another spatial dimension like another direction you can go. Any direction you can go is a combination of forward, back, left, right, up, and down
Many consider time to be the fourth dimension and you obviously can’t “see” time like you can see and wrap your head around the 3 spatial dimensions.