(December 3, 2019 at 11:02 pm)John 6IX Breezy Wrote: When I began reading your train/clock question I thought you were going to make a point on relativity. Many examples of time dilation for the non-specialist begin with some kind of moving object (train) and a clock. Of course, I understood you were just demonstrating the clock's lack of velocity. However, I found it interesting you described the clock as ticking at 17 Hz. I don't necessarily know what that means, but a constant rate of any kind be it the ticking of a clock or firing of a neuron, can be used to keep time. Isn't this rate or fequency what gets affected by velocity in relativity? In other words, there still seems to be something that ties frequency and velocity together, if not categorically, then at least causally, within relativity.
Yes, frequency is affected by SR as Alex has already mentioned. Everything is affected including your mass and colour.
Time pops up a lot in any physics discussion because it's one of the basic dimensions in which we exist. It's exceptionally difficult to describe our universe without bringing time into it, so yes, it pops up a lot in physics.