What governs the rate at which time passes?

Question

I realise that time perception can change but why does time in the physical sense pass at the fixed rate it does (1 second per second)? What governs that rate? Could time pass at a different rate in a different universe with different governing rules (maybe 1000s of times faster) such that light travels faster relative to its speed in our universe but the time perception within that universe being the same as in ours?

Answer 1

Time passing at any rate other than 1 second per second is a logical impossibility (not just a physical impossibility).

A second is currently defined as "$9192631770$ cycles of Cs-133 transition". To say something like "time is passing at 0.8 seconds per second" would be like saying for every $10$ cycles that have occurred, $8$ cycles have occurred."

such that light travels faster relative to its speed in our universe but the time perception within that universe being the same as in ours?

Time "perception" is not a universal physical quantity, but rather exists only in the head of observers and is governed by the time scale on which various biological processes operate (e.g. the time it takes for neurons to transmit signals to one another)

Answer 2

The question as formulated here does not quite make sense. Time, like any other value, can only be defined relative to something else- similarly to how it wouldn't make sense to ask why space is distributed at the scale of 1 meter per meter.

However, the second part of your question is sensible to ask. There is nothing in physics as we understand it now to prohibit us from imagining a different value of c- maybe 2.99 x 10^9 m/s rather than 2.99 x 10^8. This is because c, being a velocity, relates the passage of time to an interval of space, making it a useful quantity to talk about without having to refer to some other value it relates to.

Of course, we have to keep in mind that this wouldn't change the "speed" at which time passes, exactly, but rather change the value of other quantities relative to some arbitrary interval of time.