For Roth, or anyone else that wants to read it:
Originally at time zero, when there were no events there was no such thing as time. Once there was an event, followed by a second event (whatever that may have been) there was a measure between event 1 and event 2. Events following those of course had "distance" or time between the events. A measure could be made in comparison between the different events, thus time had been born. Man's association with time was also a comparison. Eventually man found some events that were periodic and that appeared to be precise. We developed timing systems based on the movement of the sun, moon, and stars and the repetitive cycles they had. Conveniently we found (we thought) that everything was in the same frame of reference regarding time. In other words, if two precise repetitive cycles of events were compared, the relative speed of the occurrence remained constant. We were able to develop clocks based on pendulums and such, and compare them to repetitive cycles of the sun and stellar objects. An hour was an hour, and consistent. A minute was a minute, and a second was a second consistently. All was great and convenient, since everything was within the same time frame.
Then a problem appeared. It was discovered that time for things that moved at the fastest rate possible didn't share our time frame. In other words, if you could move along with a beam of light at it's speed, it would speed across the universe nearly instantaneously. Okay, no problem, so light and other electromagnetic waves moved nearly instantly. Uh... no; that was only if you were moving along at the same speed as the wave. To observers it always appeared to move at a speed called "c", at approximately 186,000 miles per second, or the speed of light.
The light from the nearest star outside of our solar system takes about 3 years for it to reach earth. If you were traveling along with the light emitted by it, you'd arrive at the planet earth nearly instantly. Since the people on earth had spent about 3 years waiting on your "near instant" trip from the star, they would have aged 3 years while you were still processing the breath of air you took when starting your trip. That would be because you and they were in a different time frame.
It's not the light that changes the time frame. The theory was that it was speed that changed the time frame. Follow up observations have fit the expectations. So, if you could move at an outlandish rate of speed, relative to others, the rate of time would not be the same and you would literally be in a different time frame, no longer able to rely on Big Ben's timing or WWV's radio time signal.
Here's another interesting thing. Speed and gravity, as far as effect, is essentially the same. If you could enter a sufficiently great gravitational field or reduced gravitation field, the effects would be likened to a speed change, and the effect on the time frame, relative to those not in the gravitation field, would be altered.
Through out the universe you've got a wide variance in the mass of heavenly bodies. You've even got super condensed mass in such bodies as pulsars, quasars and of course black holes. Then you've got your lightweights like Earth, or even the moon. As a result, the influence on the time frame near the different bodies are quite varied and not the same as we observe here on good ol' Earth.