Something that I hope the more educated and scientifically-bended people on these boards can answer. Is time the fourth dimension? Albert Einstein sure thought it was. And I know when you add time to the equation, it does animate it nicely. But is there still any agreement among scientists today, if it's the fourth dimension?
No. You can put dimensions in any order, and number them any way you care to. It doesn't have to be fourth, and it isn't universally regarded in science as holding a fourth position. Why would it? If you're listing them and using an outline format, you can even letter the dimensions, and again, list them in any order. It doesn't have to be dimension "D". "All great thruths begin as blasphemies." (George Bernard Shaw)
Saying that light is a dimension from which we can draw coordinates of an object's psoition is like saying sound is a dimension. For example say you find a church by its bells, what did its dimension of time have to do with it?
Motion is part of physical reality. Time is the reference we use to define motion, or more vaguely change. I don't really know where I'm going with this except to say space and time are part of what define physical reality, and to wonder if there are other parts, or dimensions.
I think that the proper way to think about it is in terms of events. In order the describe an event (can be something that happens or just a things position in a certain moment) you need to determine when and where it is. If you only describe its coordinates, it leaves the time it occurred unspecified so in our universe one needs four independent coordinates to describe its location in space time. In other words, it's about degrees of freedom. The different ways otherwise identical objects or events can be distinguished from each other. One of the fundamental conjectures behind special relativity is that every object moves through the 4 dimensions at a constant rate c. If an object moves fast through the spacial dimensions, then the rate at which it experiences time must decrease (according to stationary observers) in order to satisfy the constant 4-dimensional velocity. This is the cause of time dilation, although acceleration (and gravity) can also cause similar effects.
