# Thoughts on visualizing the 4th dimension

1. Apr 11, 2005

### The Rev

Just an idea:

It occured to me that people can't see the fourth dimension because, in reality, we can't even see the third. Think about it. When you're looking at something, each of your eyes registers a 2D image, and the sense of depth (the third dimension) is inferred from the two 2D images. The mind essentially takes two 2D images, compares them, does a little intra-brain math, and establishes where things are, close to far.

So, to see the 4th dimension, we would have to infer that too. The problem is, the two 2D images we take in as data to "mock up" the third in our minds are not sufficient to mock up more than one additional dimension.

Now, if our visual system were different, maybe we COULD see the 4th dimension.

For example, if people, instead of having two eyes in the front of their head, had many free floating eyes that could surround things, and view them from different angles, we would take in a true 3D visual, with alot more information with which to "mock up" the fourth dimension. The idea of 90 degrees from everything else wouldn't be as esoteric that way. After all, it isn't hard to figure depth in a 2D image (90 degrees from everything you're taking in).

Any thoughts?

$$\phi$$

The Rev

2. Apr 11, 2005

### Someone502

i thought the 4th demension was one of the time demensions. The one that we can fell or something.

(What do they mean by 1 of the time demensions?)

3. Apr 11, 2005

### Crosson

Your ideas are interesting , but this is where your reasoning fails:

There is absolutely no reason why this should be the case. Input has nothing to do with our ability to visualize the fourth dimension; imagining a space is more fundamental then actually seeing it (we should be able to imagine anything we can see).

They mean that they believe (like a religion) in a particular theory which involves multiple time dimensions.

The currently accepted fact is: time is the fourth dimension.

Last edited: Apr 11, 2005
4. Apr 12, 2005

### Magneto

Maybe he meant other dimensions besides the ones we can sense. We can sense only the ones we need to survive day to day, what we form as "reality". After all, an animal, let's call him Fido, isn't consious of the 4th deminsion time. Only on an instictual level. Fido doesn't up at the sun and think hey it's noon - where's my gravy train?

5. Apr 14, 2005

### Tom Something

i don't believe we could see the 4th dimension even with an unlimited number of eyes. here's why:

let's picture Mr. Flat, who lives in the second dimension. Mr. Flat also has two eyes. Each eye can only percieve a set of linear data of the flat world around him. His brain takes the information from each eye to percieve "depth", the distance from another object.

Now Mr. Flat has eight eyes, each extending from his flat head at 45 degree incements. The problem is that they are still "smashed" against Mr. Flat's two-dimensional world. And they can still only look at angles that "skim" along the surface of his world. He will never see us seeing him because his eyes can't turn that way. They're still bound by the reality of his flat world.

In the same way, our eyes will always be stuck inside our "space". I use "space" to define the 3d equivalent of "plane". Our eyes can only exist in our space, and can point at angles that skim the contents of our space.

In other words, if we define the direction we're facing in our 3d world by three angular coordinates, we define the direction we are looking by x, y, z.

Assuming the existence of a fourth dimention, we would have a fourth coordinate. That fourth coordinate would always be zero.

x, y, z, 0.

But it certainly doesn't hurt to think about the fourth dimension. I myself tend to imagine the fourth dimension as being responsible for gravity, and our acceleration along this "fourth axis" causes objects of mass to bend our space. But that's for another discussion.

6. Apr 14, 2005

### JamesU

Actually, the rev is right. If you have ever listened to one of Michio Kaku's speeches, he talks about a 2-D being. This being would have skin, which would look like an outline to a 3-D being. to this 2-D being, the skin covers them all the way around, but to a 3-D being, it can see inside of he 2-D being because it's looking through another dimension.

Now, you can see how a simple outline covers a 2-D being completely, but not a 3-D being. So this makes you imagine being a "flatlander". If you think about it, a flatlander can only see a line, only one dimension. To see the second dimension, he/she would have to move or move something else.

If you apply this to uor 3-D world,you would have to find that we can see in only two dimensions at a single moment. Now aply this to a 4-D being, it can only see 3 dimensions; for example, it could see every face of a cube at one time, but to see every face of a hypercube, it would have to rotate itself or the hypercube.

7. Apr 15, 2005

### SpaceTiger

Staff Emeritus
I agree with this. The thing is, our bodies take in a lot more than just spatial information, so there's no reason that it couldn't combine its information of an object's spatial coordinates with, say, its color or smell, and compute its position on that four- or five-dimensional grid. The reason it doesn't do this is that it wouldn't be very useful; in fact, it would be downright confusing. That's because objects don't behave in nearly the same way in the "color" or "smell" dimensions as they do in space.

We will, of course, evolve to perceive dimensions in such a way as is convenient for our survival. Since, on human scales, the three spatial dimensions all behave in exactly the same way, we process them all in exactly the same way. The dimension of time is not exactly the same as the spatial dimensions, but it is very close. For the purposes of organisms, it's best to separate them. For the purposes of high-energy physics, it's best to combine them because we only need to change one relatively minor thing in the mathematics to get it to behave in the same way as space.

8. Apr 15, 2005

### cronxeh

we see 4th dimension, its called movies

9. Apr 15, 2005

### Tom Something

but aren't movies projected onto a flat screen, making time the third dimension?