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

It depends. There are a few different “master” clocks in use across the world.

For example, the US Military uses the atomic clocks located at the US Naval Observatory and maintained by the Precise Time Department. They use dozens of cesium-beam standards and hydrogen masers, which, when averaged together and sampled every 100 seconds, provided a uniform time scale with a precision of about one nanosecond (10-9 s) per day, averaged over a year.

Those clocks don’t “refer” to anything. They are the standard and what ever they say the time is is the time.