There is absolutely nothing mysterious here. It isn't philosophy, it's well established engineering and mathematics. — fdrake
My counter example works fine with nanoseconds. — noAxioms
How do you check the accuracy of your watch? You must compare it to some standard clock, say A. The same question applies to A too and so on...ad infinitum. We can never be sure of the accuracy of a clock.
The duration of a second now means:
"the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom."
And so comparisons ultimately derive from this one. — fdrake
The entire point of calibrating measurements of time is that there is a privileged time-measurer and other measurements of time are calibrated through their relationship to the privileged one. This is then what it means for two time-measurers to be in accord. If they are out of accord, they can be corrected. — fdrake
If the privileged one behaves in an unexpected way, it will be changed. — fdrake
This is because the conventional definition of time with respect to the rotation of the Earth around the Sun is slightly different from the conventional definition of time with respect to the oscillations of a Caesium atom. And thus the introduction of the leap second is precisely an attempt to calibrate the atomic clock second with proportion of a year second. This is so that we can keep the conventional organisation of time in terms of hours, days, months, years and not reinvent the wheel purposelessly. — fdrake
Convention privileges a measurer of time as a definer of the second. Then other ways of measuring time are calibrated to it. — fdrake
For the caesium-122 clock, this is an error of 1 second in 100 million years. — fdrake
But - but - we keep leap-seconds, leap-days etc so that we stay calibrated with the Earth's rotation around the sun since we don't want to reject the solar year and its monthly/daily/hourly divisions and come up with a new manner of organising time... — fdrake
This is also why the number of oscillations of the caesium atoms was chosen, since it was incredibly close to the current definition of the second but measured far more precisely. — fdrake
The cycles of caesium atoms don't differ in any meaningful way. That's kinda the point. They're regular enough to make a measurement of time to the tune of 1 second of error in 100 million years. — fdrake
Read the links fdrake posted. They answer exactly this question. At the sort of accuracy they're talking, two clocks would need to be in exactly the same environment. Put them in adjacent parking spaces and the difference in latitude will get them out of sync.How do we know that? My watch's error can be detected by an atomic clock. How do we detect the error of an atomic clock? — TheMadFool
if you are in a space ship somewhere in the universe and you have no clock, how can you measure the time with some approximation? — vesko
If you have a pulse, you have a clock. Lousy precision, but a clock nevertheless. You can time the boiling of your egg by counting heartbeats.the answer is as follows :
simple way can be the measuring of our pulse which is a given by God interval we can use to measure the time . — vesko
The counting can be (doesn't need to be) done by humans. The counting is not what time is. It is simply a human taking a measure of what time is. Plenty of non-human things utilize time measurement.So the time is nothing else but a counting of repeated events done by humans. — vesko
How do we know that? My watch's error can be detected by an atomic clock. How do we detect the error of an atomic clock? How do we know the ''1 second of error in 100 million years''? — TheMadFool
Honestly I don't understand literally everything in the paper. I trust their error analysis. If you really want me to translate the error analysis in the paper to a more convenient form I could try, but not now. — fdrake
Read the links fdrake posted. They answer exactly this question. At the sort of accuracy they're talking, two clocks would need to be in exactly the same environment. Put them in adjacent parking spaces and the difference in latitude will get them out of sync. — noAxioms
A physical process provides the definition of the second, the accuracy relates to the technology we have with which to measure that physical process. — tom
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