Alt text:
When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.
Alt text:
When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.
I would’ve said 365.25 days?
You’d be imprecise for civil timekeeping, but spot on for astronomy
The civil rule is it’s a leap year if the year is divisible by 4, unless it is also divisible by 100 unless it is also divisible by 400
We saw the rules play out in 2000 (at least those of us over 23 saw it) which is a year divisible by 100 and by 400 so it was a leap year
Yours (and astronomy’s) is Julian style “if it’s divisible by 4”
I prefer the newer calendars, where there is no good mental calculation for leap years - it’s a leap year when the computer says it’s a leap year
They skip leap years every now and then. And then skip the skip. Etc. It just doesn’t line up perfectly.
No, years divisible by 100 aren’t leap years, except if they’re also divisible by 400.
Oh right, I had some programming exercise about this, way back.
what is this, some sort of FizzBuzz calendar?
Interestingly, Wikipedia says they actually did base it on 365.25 instead of the actual 365.2425, so you’re technically right.
I don’t think that is what Wikipedia says. Whatever one’s thoughts on Wikipedia, I’m pretty sure it is getting this right.
365.25 is what you get if you have leap years every four years with no exceptions. This is what was done in the Julian calendar which was used in the Christian world some centuries ago (how long exactly depends on what part of the Christian world).
365.2425 is the average year length in the Gregorian calendar which we use (where leap years are 1592, 1596, 1600, 1604, 1608, … 1692, 1696, 1704, 1708, …, 1792, 1796, 1704, 1708, …, 1892, 1896, 1904, 1908, … 1992, 1996, 2000, 2004, 2008, …, 2092, 2096, 2104, 2108, …).
The actual average solar year is better approximated by the latter than the former, but it is still slightly off.
This seems pretty definitive to me:
That is pretty much what I said. I was irritated by your wording “the actual 365.2425”, which is just another approximation of the “actual” solar year.