Since this is I’m gonna explain my question the same way.
Imagine there is a time-hating wizard who magically removes all time-keeping instruments like atomic clocks, phones and watches, so there is no way of knowing the time right now. If then we were asked to ‘bring back’ the old time that we used (e.g. so that we start again measuring 12:00 in London exactly when it was 12:00 in London before the wizard) could this be done? Is there something physical constant (like kg or meter) that determines what time of day it is? Or, did someone just say “we start measuring time from now, and I say that it is exactly 14:32…”?
Also, if there is this constant that allows us to know exactly when a certain time is, doesn’t that mean we don’t need atomic clocks and can just compare ourselves to this constant? Idk what this would be but perhaps when the sun is absolutely highest in the sky somewhere?
In: 40
To answer your question about whether we could create a correlation between the “old time” and the “new time” if we somehow had a “gap” in between the two (a not totally impossible idea, if you had a total civilizational collapse and much later rebirth) — astronomical records can be used to make such correspondences. This is how we can figure out what the dates of some very old events are in our modern system, because in the past there were people who kept very good records of things like eclipses that we can, with modern astronomical models, very precisely date.
There is no “constant” for time in the universe of the sort that you mean. But if we define some sort of event as the “beginning,” we can certainly say that some measure of time (say, rotations of the Earth around the Sun, or Earth rotations on its axis, or the vibration of piezoelectric atoms at a given frequency of electricity, etc.) has passed since that moment. So we could say, “ah, it is day X since that wizard cast the spell.”
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