What is the 4th dimension, and is it viewable by the human eye?

Answer 1

The fourth dimension is time, but let me explain. It is a simple concept that is often obscured by a lot of nonsense.

Let's start with what a "dimension" is to a physicist. It is not some mysterious, mystical place. It is a straight forward mathematical concept. A dimension is just a mathematical parameter needed to define a postion in a coordinate system. When a physicist or a mathemetician asks how many dimensions a particular space has, he is merely asking how many numbers, or parameters, are needed to define a particular point in that space. Some examples will make this clear:

Take an ordinary number line like this:

-3 -2 -1 0 +1 +2 +3
<--I----I---I---I----I-----I----I------>

This is a one dimensional coordinate system. All this means is that it takes only one number to specify a position on the line.

Take an ordinary x/y coordinate system like this (I don't know how to make this render properly here, but you know what an x/y graph looks like, right?):

y
I
I
x ___________I_____________
I
I
I
I

This is a "two dimensional" coordinate system. All this means is that it takes two numbers, the X coordinate and the y coordinate, to specify a position in this system.

Now you can add a "Z" coordinate to this system, and you have a 3 dimensional system. Again this just means you need 3 numbers to specify a position in the coordinate system.

Now, mathematically, we can add as many "dimensions" to our coordinate system as we want. We can have a 12 dimensional space if we want. This just means that in our mathematical equations we will need 12 numbers to specify a position in this 12 dimensional space. This is only confusing if you insist on trying to "picture" a 12 dimensional space in your mind. We can't do that because our brains are evolved to think in 3 dimensions. If you don't think of it as representing a physical space, but just as math, it is not so confusing.

So why is time the 4th dimension? Simple. If we want to specify not only WHERE an event happened in our three dimensional space, but also WHEN it happened, we need 4 numbers. In our everyday world on Earth, those 4 numbers would be latitude, longitude, altitude, and time. In a more abstract mathematical sense, they are just 4 coordinates, X, Y, Z and Q, for example.

Mathemeticians work will all sorts of "spaces" and geometries with many more than 3 dimensions. This does not represent a real, physical space to them. It is just abstract math.

Theoretical physicists try to create mathematical models of real world processes, such as models or what they see when they smash atoms together in particle accelerators. Sometimes they find they can make the math work by adding extra dimensions. Some theorists think they need 12 dimensions to make their math work. Others come up with different numbers of "dimensions," - 4 or 6 or 13. This DOES get confusing, because now we are talking about models of the real world so we naturally want to "picture" in our minds what this 12 dimensional space would look like. Well, we can't picture it, and neither can the physicists. But they can do the math without picturing it: it's just more variables in the equations.

Answer 2

No we can not see the fourth dimension.

If you really want to know a lot about dimensions and all of that stuff there is a great novel (it is a very easy read) called Flatland by Abbott


It is a great book... you should really read it (its only about 100 pages (if that) and a very quick read)

Answer 3

Time is widely considered to be the 4th dimension. I believe Einstein was a firm believer of this.

Answer 4

many scientists believe it to be time.
mathmeticians have worked out how to find the area of a 4d object, even though they have no idea what it would look like.

Answer 5

you just need a telescope