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

There are 2 simple answers. Yes, there’s a master clock (sorta), but the real marker of time is the Sun.

First, yes, there is a master clock. There are hundreds of atomic clocks in many countries that keep time more accurately than humans are capable of noticing. Coordinated Universal Time or “UTC” is how all these atomic clocks work together. In a sense, it’s like a single master clock.

Second, the real master clock is caused by the Earth’s movement and the Sun’s position in the sky. So we can measure the “true” time relative to Sun’s position over a specific point on the Earth. Sometimes, human clocks (including UTC) have to be adjusted in very tiny amounts because they need to match the Sun more closely.