Time is not a tangible. It is neither a field nor a fabric. It is simply the comparison of two (or more) rates of change. It is a measurement, like measuring distance with a ruler, but instead of evaluating an unknown length against a standard unit, you are measuring the quantity of change occurring within one sequence against the progress of some other standard event like the rotation of a planet or the vibration of a cesium atom. As with any comparison, the measurement of time is dependent upon the frame of observation.

Things change in two basic ways: internally (relative to itself) and externally (relative to other objects). There is, of course, a limit to the rate at which things can change. That limit appears to be related to the speed of light and nature somehow seems to balance it with a trade-off between external change and internal change. At relatively low speeds, motion doesn't seem to impede the rate of internal change. At 60 miles per hour, a clock seems to keep perfect time, but as it approaches the speed of light, its rate of change declines and the clock ticks ever more slowly. Interesting, isn't it?

The concept of time has been highly over-mystified due to the illusion imposed upon our thinking by the phenomenon of memory. By engaging our memories, we can conceptually revisit past events. Time is nothing more than change, and though some changes can be reversed, to actually go back in time it would be necessary to find a means to halt all processes in the Universe and then successfully apply sufficient force to reverse them throughout the cosmos. Even such an extraordinary procedure would not reverse the course of time. Whatever process was engaged to controvert time would also have to CEASE acting at the same temporal point it began - for if it progressed, so would time.

Mathematically it may be convenient and even expedient to consider time as a dimension, but other than the physical changes it measures, it has no separate existence or reality of its own. The term 'dimension' is best left to describing spatial relationships.