what is the fourth dimension in 4D?

Question

i know its time. but how is time related to dimensions. can someone clerify this for me.

Answer 1

it means that some place ( x,y,z) in space , say the toilet , is not the same anymore when you come back later. there is no magic behind it, so (x0,y0,z0,T0 ) is not (x0,y0,z0,T1 ) it is another point

Answer 2

Like you said, time is the fourth dimension, and acts strikingly similar to the 3 space dimensions.

With 1 dimension there is one variable. All you can draw is a line in one dimension, so the only variable is the x value...or in other words how far along the line you are.

With 2 dimensions there are two variables, and you can draw areas. You can walk along the x axis any distance and then the y axis to get any point on the area.

With 3 dimensions you've got an area expanded into depth, with 3 variables. You can walk along x and y for any point on the area, and then "climb the stairs" along the x axis any distance for any point in the volume.

With 4 dimensions you do those first 3 steps to find some point in the volume. Now you have to walk along the "time" axis to get your final 4-D point.

Let's take my dad as an example. The point in 3-space we're looking at is the top of his head. At the beginning of the "time" axis it was close to the ground. Then as we walk along the time axis the point rises and rises and then eventually starts falling a little bit.

Time is just another variable. However, unlike space, we can't pick where we are in it. We're like stickmen on a piece of paper floating through the air. We're travelling in 4 dimensions but we can't time travel, we can only space travel.

Answer 3

This is one of those things that is just so, even though you don't quite understand it. The theory of relativity (specifically, the theory developed by Minkowski) implies that there is no essential difference between the spatial dimensions and the temporal dimension. So, time truly IS the fourth dimension.

It's hard to understand because time has a directionality to it, which space does not. I haven't been able to make that make sense, but I accept that it's true because that's what the equations say, and the equations fit what we actually see.

Answer 4

I heard it explained when someone was talking about baby sonograms in 4D. They have traditional sonogram pictures in 2D. And they have newer ones in 3D. But a 4D one would have to be in video form, not photo, because you would then see the baby's movements in Real Time, as it happened, no delays. So seeing video, with the 3 dimensional picture, and then actual movement over a span of time is the "4th dimension".

Hope that makes sense.

Answer 5

It's just a part of the way the equations of physics have worked out to be since Einstein. Simplistically it says mathematically that you can't be in two places at the same time.