How do we actually know what the time is? Is there some “master clock” that all time zones are based on? And if so, what does THAT clock refer to?

Question

EDIT: I believe I have kicked a hornet’s nest. Did not expect this to blow up! But I am still looking for the “ur time”. the basis for it all. Like, maybe the big bang, or something.

In: 5399

Answer 1

time zones are based on Greenwich Mean Time, which was adopted by the British to enable their ships to navigate the world effectively, using shipboard clocks to calculate longitude (the distance from Greenwich)

As the British effectively conquered most of the world, this standard of time became accepted as a way of keeping everyone on the same page. It was succeeded by UTC, Coordinated Universal Time where the base time zone is still England (Greenwich) and the other time zones count ahead or behind that time.

the “Master clocks” are atomic clocks that are set to this UTC. Greenwich is still +-0, while other time zones count from there. I’m in Vancouver, so UTC-8

since time and space are the same thing, human measurement of time is entirely a construct; but we need some way of coordinating our activity, and labeling units of time is an effective way of doing that