I feel like the time thing is less an issue than other systems because it’s better adopted across the world. Part of where metrication came from is that each country would have their own standard for how long a foot or how big a gallon was, but the months, weeks, days, hours, minutes and seconds are pretty well agreed these days. Most units can be selected arbitrarily without changing much about their usefulness, but with time you want to stick as close as possible to solar days, number of solar days per year, and maybe line up with some seasons/solstices/equinoxes. Changing the sub-divisions of the day also means we’d probably want to re-draw time zones, so we’d want a subdivision that can be reasonably easily divided by something close to 24. I guess you could have a 10 hour day and each hour be 100 minutes, or some such and move to 20 or 25 time zones to keep relatively consistent. A 10 day week doesn’t divide evenly into a year though. The divisors of 365 are 73 and 5, so I guess you could do 10 and have one of the weeks split somewhere, but then you still have to deal with the occasional leap year.
Then there’s the consistency issue, the length of a day varies over time, so regardless of the subdivisions we choose, high precision measurements are going to need to account for that to keep our time in line with the solar day.
You’re definitely right that people can agree on the length of day and year regardless of where they live. This way, there’s no urgent need to change that part of the system.
Since 365ish isn’t a number you can neatly divide with anything, I suggest we just pick some number you like, and then add a leap day when needed. So, let’s say you want to divide the year into 10 decimal months, so let’s call them “donths”. Each donth has exactly 36 days, which means that at the end of the year you still have 5ish days left. It’s not exactly 5, because astrnomy, but don’t worry about it. Then you’ll just lump all the remaining bonus days into an extra donth and you’re done. The length of the first 10 donths is always constant and the length of the leftover extra donth at the end of the year is whatever it happens to be. You could make those days a national holiday when people just wait for the new year to start or whatever.
I feel like the time thing is less an issue than other systems because it’s better adopted across the world. Part of where metrication came from is that each country would have their own standard for how long a foot or how big a gallon was, but the months, weeks, days, hours, minutes and seconds are pretty well agreed these days. Most units can be selected arbitrarily without changing much about their usefulness, but with time you want to stick as close as possible to solar days, number of solar days per year, and maybe line up with some seasons/solstices/equinoxes. Changing the sub-divisions of the day also means we’d probably want to re-draw time zones, so we’d want a subdivision that can be reasonably easily divided by something close to 24. I guess you could have a 10 hour day and each hour be 100 minutes, or some such and move to 20 or 25 time zones to keep relatively consistent. A 10 day week doesn’t divide evenly into a year though. The divisors of 365 are 73 and 5, so I guess you could do 10 and have one of the weeks split somewhere, but then you still have to deal with the occasional leap year.
Then there’s the consistency issue, the length of a day varies over time, so regardless of the subdivisions we choose, high precision measurements are going to need to account for that to keep our time in line with the solar day.
You’re definitely right that people can agree on the length of day and year regardless of where they live. This way, there’s no urgent need to change that part of the system.
Since 365ish isn’t a number you can neatly divide with anything, I suggest we just pick some number you like, and then add a leap day when needed. So, let’s say you want to divide the year into 10 decimal months, so let’s call them “donths”. Each donth has exactly 36 days, which means that at the end of the year you still have 5ish days left. It’s not exactly 5, because astrnomy, but don’t worry about it. Then you’ll just lump all the remaining bonus days into an extra donth and you’re done. The length of the first 10 donths is always constant and the length of the leftover extra donth at the end of the year is whatever it happens to be. You could make those days a national holiday when people just wait for the new year to start or whatever.