In my opinion

TIME is related to ACCELERATION

The famous race.
This time between a tortoise and an athlete.
The goal post is 17 meters away and the tortoise is given a one minute head start.

Suppose that a tortoise is able to travel one kilometer in one hour, then it will travel about 16.7 meters in one minute.

Now suppose that an athlete is able to run 15 kilometers in an hour, then in 30 minutes he
will have traveled 7.5 km. In 15 minutes he will have traveled 3.75 km, and in 7.5 minutes he will be about 1.9 km away, in about two minutes he will have traveled about 469 meters. In order to catch up to the tortoise, that has a head start, the athlete must ACCELERATE from a standstill to a speed that will take him to where the tortoise is, 16.7 meters away, in about four seconds, otherwise the tortoise wins.

Acceleration is very important in all phenomenon that involves motion.
In fact, my belief is that the ‘constant’ in Einstein’s formulas should be considered as the ‘acceleration’ of photons rather than their speed.

Johannes