Comment by picafrost
3 months ago
This is a great and very interesting write-up. It has never occurred to me that there might be algorithms applicable to calendars.
It strikes me that the Gregorian calendar might encode some of the most calcified tech debt of humanity. It attempts to fit solar, lunar, and 7-day religious-oriented cycles (and who knows what else?) into one system. So many cultural and religious touchstones are oriented around the (month, day) tuple. For extra confusion add the asymmetry between cultures who place traditions on the lunar calendar. Let's not mention timezones. A big thanks to you keepers of time (libraries).
Deciding that time began with Unix and that it should simply count forward seems rather sane by comparison.
My favorite technical debt is the off-by-two naming of quintilis through december from when they added Jan and Feb to the beginning of the calendar...
Yup. And directly related to that, the absurdity of having the second month be the one that has weird numbers of days and gets a regular extra day to keep the calendar in sync with Earth's revolutions. Adding or removing a day from the end of the year is the obvious choice, so why not do it there?
Turns out, people who came up with the leap year weren't stupid - the extra day used to be tacked to the end of a year. But then the thing you mentioned happen, the calendar was rotated right (in the positional arithmetic sense) by two, and what used to be the last month of the year is now called February.
Yeah, I never understood why they couldn't make it Dec-Feb-Jan with January at the end of the year so that Janus could still be the god of transitions, but I guess I'm no theologian so there is probably a reason.