Facts about 2025
Jan. 1st, 2025 02:46 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
andrewduckerFact of the day: 2025 is a square year, as its 45*45. The next square year is 2116 (46^2)
45 is also 20+25, so 2025 = (20 + 25) ^ 2. Someone with less children about can run the numbers on how often that's the case.
Of course, 2000 years ago square years were happening every few years. Nowadays you're really unlikely to live through two.
Which led me to wonder when people started counting years using the current method. The answer being between 525 and 730 - with Portugal holding out until the 1400s. Before that was the Era of the Martyrs and regnal numbering ("5th year of King James"). Fun fact, documentation of UK's parliament was still done this way until 1962*.
In any case, that means that the first square number counted in the current year numbering system would be 576 - with the next one being in 625. So if you were born in the century after that you'd have a reasonable chance of living through two of them, if not *that* high, depending on exactly which year you were born in.
Obviously there are many other year counting systems around the world. My favourite regnal one, discovered while going through this, is the Anka Year which skips years ending in 6. And some ending in 0. But not all of them. I'm sure there was a good reason.
*I was ⅔ of the way through writing this (on my phone, while looking after three children) when David Allen Green posted this marvellous look at how the changeover happened.
45 is also 20+25, so 2025 = (20 + 25) ^ 2. Someone with less children about can run the numbers on how often that's the case.
Of course, 2000 years ago square years were happening every few years. Nowadays you're really unlikely to live through two.
Which led me to wonder when people started counting years using the current method. The answer being between 525 and 730 - with Portugal holding out until the 1400s. Before that was the Era of the Martyrs and regnal numbering ("5th year of King James"). Fun fact, documentation of UK's parliament was still done this way until 1962*.
In any case, that means that the first square number counted in the current year numbering system would be 576 - with the next one being in 625. So if you were born in the century after that you'd have a reasonable chance of living through two of them, if not *that* high, depending on exactly which year you were born in.
Obviously there are many other year counting systems around the world. My favourite regnal one, discovered while going through this, is the Anka Year which skips years ending in 6. And some ending in 0. But not all of them. I'm sure there was a good reason.
*I was ⅔ of the way through writing this (on my phone, while looking after three children) when David Allen Green posted this marvellous look at how the changeover happened.
