I’m from New Zealand and he sounds like people from here who have spent a lot of time in America, but honestly idk what a Scottish/USA accent sounds like, so they could sound the same
so i was vaguely aware of this bc it came up in a computer science class i took in high school, it was supposed to tell you if the year you input was a leap year or not and the teacher explained these rules
but i couldn't remember them exactly and bc of 2000 being a leap year i convinced myself i was misremembering there being an exception to every 4 years and so i just now learned that my vague memories were correct lol
It turns out that there's not anything like even a neat fraction of days in a year. So we have to add a day every 4 years EXCEPT that's a little too much so only 24 per 100 years BUT WAIT that's not quite enough so actually it's 97 per 400 years. We can keep going deeper
Just wait til we add in the part where days are getting longer due to the moon. Technically at some point in the future there will be *exactly* 25 leap days per century for a little while
To both you and Lauren:
Leap years are used because a year (the time it takes the Earth to circle the sun) is not exactly 365 days: it's closer to 365¼ days. But it's not EXACTLY 365¼ days, either. So every 100 years, another adjustment is made. But that adjustment isn't 100% accurate, so every 👇👇👇
400 years, another adjustment is made... And so on.
If we didn't make these adjustments, gradually the seasons would shift relative to the date (and vice versa), so that in the northern hemisphere, it would be summer in January (before continuing to shift to July again, and so on & on).
Yup, I learned about this in the run-up to 2000, when everyone was worried about the Y2K bug, & @rbreich.bsky.social pointed out on @npr.org that nobody was talking about how 2000 was an exception to the leap year rule. So, even if the computers didn't crash on 01/01/00, they might do it on 02/29/00
Welcome to my personal hell. It does at LEAST explain why non-human animals know what time it is. Allegedly they can smell it. I wish I was dumb I didn't wanna know this but I do.
The thing that upsets me is that I *did* know that, because it's been relevant in programming, and it's part of why everyone straight up tells you to not write your own time handling code.
Yeah it’s because the length of a solar year is 365.242 days, so if you did it every four years regardless things would start to get more out of whack…
This came up with the Julian Calendar which was in use for 16 centuries and ended up drifting by almost two weeks
I think there are further refinements that could be made (not leaping if the year is divisible by 4000) but it’s probably not worthwhile because something is likely to perturb the earth’s orbit beforehand
Ok, this sounds crazy but we're doing the best we can about the reality that the earth does not give a shit, it will not circle the sun at exactly the perfect rate that would match up at all w/ the rate at which it spins, it's all just a bunch of flaming balls, we fit things together as best we can
Astrologers plotted out constellations 100s of years ago, made this whole big system out of it, read a lot into it, but the modern constellations don't match their estimates, cus, as it turns out, over 1000s of years, the whole Earth wobbles:
I was once in a church in Moderna, Sicily where they had a sun clock that charted all this out, including some understanding that the years/days did not all match up: they had built this clock centuries ago, mostly for farmers, people that care about the truth of the sun being up and down precisely.
But then the railroads came, and the railroads didn't care about the waxing and waning of the moon and sun, the days growing longer and shorter: they cared about math, and math said that days are always exactly this long, always, because that's what makes the math easy.
oh yeah this is what caused the gregorian calender switch up. they realized the solstices had drifted 12 days in 1600ish years because they were leaping too many days
Which to us normal (ish?) humans is a bit yawn. But to the religious guys in charge, it was terrible that Christ's birthday was slipping year by year. Oh noes!!!
I've always found it neat from a "measure shit accurately" standpoint though. It's pretty clever.
Comments
Mary was merry when she married merrily. Crikey milady, them's the breaks. On god
Leap years aren’t just every 4 years. They’re very 4 years unless that year is divisible by 100. So no leap year in 2100.
But there was one in 2000 if you remember. That’s because the exception to the exception is if the year is *also* divisible by 400.
WHAT
It turns out that there's not anything like even a neat fraction of days in a year. So we have to add a day every 4 years EXCEPT that's a little too much so only 24 per 100 years BUT WAIT that's not quite enough so actually it's 97 per 400 years. We can keep going deeper
Leap years are used because a year (the time it takes the Earth to circle the sun) is not exactly 365 days: it's closer to 365¼ days. But it's not EXACTLY 365¼ days, either. So every 100 years, another adjustment is made. But that adjustment isn't 100% accurate, so every 👇👇👇
If we didn't make these adjustments, gradually the seasons would shift relative to the date (and vice versa), so that in the northern hemisphere, it would be summer in January (before continuing to shift to July again, and so on & on).
Helpful?
IF YOURE A DICK ABOUT IT YOURE GETTING BLOCKED JFC LEARN HOW TO BE ACTUAL HUMAN BEINGS
Anyway. How’s everyone doing feeling thinking
https://scienceworld.wolfram.com/astronomy/LeapYear.html
SOME OF US were too busy making sure planes weren't going to crash on 1/1/2000 to worry about February.
https://en.wikipedia.org/wiki/Time_Cube
This came up with the Julian Calendar which was in use for 16 centuries and ended up drifting by almost two weeks
The solar year looks at the length of time between two equinoxes
The sidereal year looks at how long to complete one full orbit relative to the constellations and is about 20 minutes longer
Genuinely appreciate it. Always love learning more 💜
It’s not likely to come up for anyone who was alive in 2000 so we really can just go with the every four years shorthand and it will be correct
But it’s a fun bit of esoteric knowledge
😎👉👉
https://en.wikipedia.org/wiki/Leap_second
burn all clocks and masters
https://nasa.tumblr.com/post/150688852794/zodiac
And the clock was forgotten
I've always found it neat from a "measure shit accurately" standpoint though. It's pretty clever.
(I'll stop talking to myself now)