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

Yes, it’s called [Coordinated Universal Time](https://en.wikipedia.org/wiki/Coordinated_Universal_Time) (UTC). All time zones are defined as being a certain number of hours and minutes ahead or behind UTC.

The time itself is based on a weighted average of several atomic clocks located in laboratories all over the world.