by Nik Fisher

Created on: November 24, 2008   Last Updated: November 30, 2008

Time and space is always a fascinating topic. I find myself listening to anyone that knows anything on the topic. One thing we always hear is that time is the "fourth" dimension. What does this mean? I have thought about it and while I admit that I have very little grasp on the topic, I feel I have an interesting way on conceptualizing a "fourth" dimension.

The first step is to suspend the illusion that time is somehow moving. We need to accept that time is no different from space except that your conscious moves through time at the rate of one second per second. Like space, all things that exist in time occupy a place in time. Take an arbitrary point in space and call it the origin. The origin is not the first of anything, but the reference point which we will measure all other points. Space is three dimension, so the coordinates of the point in space is (0,0,0). Then if we incorporate time into the mix, there are four dimensions for our point, say (0,0,0,0).

This is where it gets tricky. It is easy to envision all points in space of the form (x,y,z). Think about looking around the room you are in, picturing all of space is the same idea except on a larger level. Trying to apply that concept to time is a bit trickier, because the mental image we have of space is based on one specific moment in time. In order to fully see time, we would have to be able to imagine every moment of the space in your room stacked on top of each other.

As a species we are a bit limited in our imagination, so picturing that fourth dimension is very difficult. The trick I like to use is to think of an analogy. Cubes are three dimensional shapes in which every side is the exact same size. A cross-section is a sliver of a shape, such that we can take on dimension to "zero." For example, our cube has length, width, and height of length one inch. If we squish that cube so that the height becomes zero we are left with a square, so in a way we can think of a cube as an infinite number of squares stacked onto each other. Another way to think of this is from a very old (in fact you can get it for free on line legally now) book called Flatland: A Romance of Many Dimensions. In Flatland the main character is a square, who meets a sphere. The square does not comprehend height since he is only two dimensions and instead sees the sphere is a circle and grows and shrinks in size. When the sphere first crosses the square's world, the square sees a single point, which is the top of the circle. The point

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