Yeah, even at the fundamental level, there are fudge factors that vary from year to year and can only be worked out by astronomical observation. Just measuring

Yeah, even at the fundamental level, there are fudge factors that vary from year to year and can only be worked out by astronomical observation. Just measuring what is meant by 'year' is a tricky problem: https://en.wikipedia.org/wiki/Year#Sidereal.2C_tropical.2C_and_anomalistic_years https://en.wikipedia.org/wiki/Year#Sidereal.2C_tropical.2C_a...