Thread: Explain to me the 4th dimension.

Fourth dimension is time, the measurement between events, rather than points. WE move through the fourth dimension at... a fairly uncontrolled rate, though that rate varies slightly with our velocity. The average person doesn't have much control on their journey through time. Didn't watch the video, can't, but if there's anything more specific you want to know, you'll have to ask, since I can't do that for you.

If time is the 4th, then I am refering to the 5th. I know how time works, I have a basic grasp on how we move 'through it'. I am talking about the next dimension.

This is very helpful in attempting to understand the 4th dimension.

http://www.geocities.com/CapeCanaver.../whatis4d.html

Time does not exist except as a mesurement of space. It is not the 4th dimension.

From what I can tell from the image, I'd have to say that the fourth dimension is something that is imperceptible in a normal state of consciousness. You probably have to be on drugs to experience it from within human consciousness if it is possible at all/is even a "real" thing. Human consciousness creates a 3D perspective of reality. I suppose it's possible to visualize a four dimensional shape, but because our perspective is limited to 3 you can build anything like that.

I'd really like to see a 3D hologram of something in 4D. Now that would give you a better idea.


I've never really thought about this too much before. Every thing I've read about it seemed like complete nonsense, but that image makes some sense.

This was fun I thought

Ignore these people. The 4th spacial dimension is not time, and it is definitely not some weird plane of consciousness.

It's an unanswered question why there are 3 spacial dimensions in this universe, and not some other number. There is absolutely no reason why there shouldn't be, and anybody who tells you there is is simply an unimaginative person. All other spacial dimensions are just as mathematically - logically - consistent as these.

To think in terms of the fourth spacial dimension, it is actually extremely easy.

First, picture a dot. This is the 0th spacial dimension. There are no degrees of freedom at all.

Second, imagine this dot splitting like a cell into two dots, some distance apart, and between them, they draw a line, like a spider drawing a thread. You now have a line with two dots at each end; this is the 1st dimension, and there is 1 degree of freedom.

Now, imagine these two dots splitting into four in the same way as before. Separate the two new dots and again join them up with lines. You have a square, the 2nd dimension.

Do it again. Split these four dots into eight, separate them, and you have a cube, the 3rd spacial dimension.

And then do it again. Split the eight dots into sixteen, and separate them. You now have two superimposed cubes. Obviously this is a mere shadow of what a 4 dimensional cube (called a tesseract) actually is because it is not possible for the human neural network to comprehend such things, but nevertheless, it gives you an extremely clear idea of what one is, much like drawing a cube on paper gives you a clear idea what one is, even though the 'depth' cannot be transcribed onto the paper.

In Einstein's theory of general relativity, basically he creates a mathematical framework in which you interpret this fourth dimension as time; but that is a physical theory. It is completely separate from what you wanted to know, which is the mathematical generalisation of n-dimensional forms.

And you can continue to expand upon this; a cube in the 5th spacial dimension will have 32 verticies, a cube in the 6th spacial dimension will have 64 verticies, and so on.

Hope that helped.

If you were to travel in a straight line in our universe, you would eventually end up in the same place you started. This phenomenon is not unlike that of a two dimensional character on a mobius strip who finds that they have reached their point of origin after having traveled in a "straight line". What that two dimensional character doesn't realize is that their world actually curves through another spacial dimension one above their own (a mobius strip has to bend through three dimensional space in order for it to have only one boundless and finite side). In our universe the same things happens, but through another spacial dimension of which we are perceptually unaware of. Because of our natural inability to perceive four dimensional space, we cannot easily comprehend what exactly it "looks like".

I wish I could expound upon that further, but I think I speak for more than myself when I say that we really can't go any further with our explanation of a 4th spatial dimension without using analogies and mathematical expression.

Actually there's no evidence at all for that.

Originally Posted by Xei

Actually there's no evidence at all for that.

Exaclty. There's evidence to the contrary

If the universe is curved, the corners of a triangle wouldn't add up to 180 degrees. Very, very precise measurements have shown that this universe isn't curved, not at all. The corners of a triangle in our universe add up to exaclty 180 degrees.

Xei, I Was really hoping you would intervine. I knew you would be able to help me out

It really heaps, I get it to an extent. I understand how shapes 'evolve' when they go to new dimensions. I do not understand how a teserect can be the shadow of a 4D figure, but I guess a 2D creature wouldn't be able to comprehend a 3D shadow (even if a shadow is 2D).

Thanks, I get it as much as I wanted to.

I heard that in the fourth dimension, it is possible to view a cube from all sides at once. Right?

Originally Posted by dajo

This was fun I thought

Fun, but woefully inaccurate I'm told.

I would assume so, because us 3D creatures can see a 2D square all at once. But it would be impossible for a 4D creature to see the 4D eqivilent of a 3D cube (see quote).

Split the eight dots into sixteen, and separate them. You now have two superimposed cubes. Obviously this is a mere shadow of what a 4 dimensional cube (called a tesseract).

But it would make sense for a 4D creature to see a 3D cube all at once. Right?

Exactly. We can't make sense of 4D cubes, so the ame must apply for the others.

But alternitively, we can see the shaddow. A 2D critter can see the shaddow of a cube.



That is a 2D image. Of a 3D cube. It wouldn't make sense, but it can be seen. The shaddow, anyway. So we can see the 3D shaddow (what?...) of a teserect. Right?

And would I be able to 'see' (or at least experience) a 4D shape in a LD or a AP (if you believe in AP)

Hmmm? No, that's not a cube, or a cube's shadow at all. That's a 2D drawing of what a cube looks like to us.

Originally Posted by Reality_is_a_Dream

It is very cool and all, but it doesn't explain nothing to me. So I figured that I would ask the smartest fourm I know.

Double negatives make me horny.

I'm on my iPod,so I'm going to have to completely ignore preceeding comments. The fourth dimension would be seeing every side of something. We see in the second dimension, only seeing a two dimension representation of an object. I'm pretty sure that seeing in he fourth dimension would be like looking at all side of something. What yu have Thier is a tesseract or hypercube. Read a wrinkle in time, it goes into it a bit

Despite what some have said here, human beings are really only capable of directly (visually) percieving 2 dimensions. What you see is not 3 dimensions, otherwise you would be able to see both the front and back (plus all other angles) of an object. What you really see is a stereoscopic 2 dimensional picture (2 eyes) and your brain approximates variable distances to create a 3 dimensional model. Now, if you can imagine the capability of truly seeing in 3 dimensions; seeing an object from every angle at once, then you might be able to imagine a situation in which you could form a sort of stereoscopic picture of the 3 dimensional world to approximate 4 dimensions. What this might be is somehow simultaneously percieving three dimensional objects in their full range of positions as they move through space. Kind of like being able to see a person live out their life from beginning to end in real three dimensions all at once.

A good way to imagine this would be to just look at the end of ruler and imagine that it is only 1 dimension, and then turn it so that you can see it head on and realize that it is really 2 dimensions (ignoring thickness).

If you want to put it in terms of the video you posted, all you have to do is realize that when the lines seem to shrink, grow and pass through each other, they aren't really changing or passing through each other, you are just seeing the object from different angles. It would be the same if you had a 2 dimensional animation of a 3 dimensional cube. The lines would appear to shrink and grow, and then pass through each other depending on which was in the foreground and which was in the background.

I found some good sources for visualization. The first is a stereoscopic image of a tesseract, found on wikipedia. You need to do the magic eye cross eye thing to see it.

The second is an article about mapping 4 dimensional objects to a 3d projection of a tesseract in order to visualize what they look like. It goes in to more depth, and also explains why this is useful.

Originally Posted by Xaqaria

Despite what some have said here, human beings are really only capable of directly (visually) percieving 2 dimensions.

THAT'S WHAT I FUCKING SAID!
Shit.

We see in the second dimension, only seeing a two dimension representation of an object.

Calm down. Clearly you weren't part of the "some."

Haha, wow.

Visually imagining a 4 dimensional object would be extremely hard and would probably require advanced knowledge about its properties. Visualizing that is like a 2 dimensional person visualizing 3 dimensions, they just couldnt do it. The fourth dimension would be perpendicular to the 3rd dimension, so you couldnt see it or recognize it if it were there.

Great link that explains alot : http://tetraspace.alkaline.org/ It will help you understand alot about the fourth spacial dimension

Hope i helped a bit and you find this useful

Originally Posted by Reality_is_a_Dream

It is very cool and all, but it doesn't explain nothing to me. So I figured that I would ask the smartest fourm I know.

Please explain this to me, I feel like I need to know. I can understand the 2nd and 3rd dimensions, but the fourth is a little less understandable. Thanks!

To better understand the difficulty of picturing 4d objects, consider the difficulty a 2d being would have conceiving of a 3D world.

You should read the book Flatland, available online here:
http://www.geom.uiuc.edu/~banchoff/Flatland/
There are several movie versions of the book available as well if you can find them.

Or check out Dr Quantum