TL;DR: mostly ancient math and moon stuff.

This article suggests 60/60 came from the Sumerians who used a base-12 counting system. This and other articles note that 60 is more flexible than 100 in many ways as it’s divisible by 2, 3, 4, 5, and 6.

The Babylonians invented the 360 degree circle, and so understood the sun to move about 1 degree per day.

The number of days in a week and weeks in a month is based on lunar phases (month=moon, and in Chinese the word for month is the same as moon, 月). This article says the approximately 28 day month is traced to ancient Mesopotamia with leap days used to stay consistent in the long run. As for days of the week that article also says they were based on the 7 non-fixed heavenly bodies visible to the naked eye.

The only metric unit of time is the second. all the other ones are customary units that are geared towards living on Planet Earth. There was a movement for decimal time at one point, but it never really took off. Given that the length of a day changes, I don't see how it would remain stable either. Which is something that SI units try very hard to make sure doesn't happen.

12 hours in half a day is fine for me. 12 can be divided into halves, thirds, quarters and sixths. That's useful for planning out a day. Time is one of the applications where I don't have a complaint about using base 12.

Well, the time for eath rotation isnt a constant, it will slowly decelerate and days will be longer.

Using multiples of 10 for time was considered, but was a shitty option compared to the current deal. Months should all be 30 days and then have a free week at the end of the year tho, egyptian style.

Americans use the imperial system, yet claim not to be imperialist. Curious 🤔

Time measurements like heat, mass, length etc are arbitrary units. It is just that they are the oldest.

The Sumerians gave us our time standards and they loved base 12. So twelve hours in the day and 60 (5x12) minutes in the hour. Also 12 months in a year and 360 degrees in a circle.

The French actually tried to implement decimal time after the revolution but reverted back after 6 years or so.

Splitting hours and minutes into base 60 started with the Sumarians like 5000 years ago, passed down to the Babylonians, and just kind of stuck around. 60 is great because it has a bunch of factors - 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60 - so it's easy to split up into even parts. Apparently it's called Sexagesimal

A year being ~365.25 days long is simply how many times the Earth spins on its axis during a full orbit around the sun, because the Universe does not give a shit about being neat and orderly. Months and weeks are just figuring out how to manage it the best we can. Kinda dumb that February has 28/29 days though, like there's a bunch of months with 31 days stop hogging them all and let February have a couple more, assholes.

Since we are on the topic of time measurements, take Caesar and Augustus's names off of my calendar please and thank you.

Also, if you can fill in February to be full 30 days, that'd be great as well. Take a day off from each of the emperors.

Unfortunately, seasons, years, when it's light out compared to the length of a day... These are not conveniently metricised.

Writing this in 634.023.M3 Imperial Calendar i agree we should change it to juche

Because there's 365 days in a year (duh). I mean, if it were, like, 200, then a year would be 0.7 season cycles?

Same for a day. If we set it to, say, 10000 minutes or whatever, noon could very well end up as the middle of the night eventually.

As for the minute and hour, how else would you fit seconds into a day? 24*60 square rooted for equal units? So we have 120 new minutes each 120 seconds long? I mean, I could see that sort of working? But it's still pretty weird, and not a true decimal. So I guess you'd have to rework seconds also.

Edit: months are based off the moon, and there would be no way to somehow make units of 10 months fit into a year, which literally cannot be anything other than 365 days, unless you want your afternoon tea parties 0.12 daylengths past midnight.

Please don't touch it now

-- the entire software developer community around the world

The main reason is because we use natural cycles that are important for civic and agricultural reasons as the basis of our measurements. And those cycles are unrelated phenomena that don't match with each other well.

Day and year are based (duh) on two solar cycles (Earth's rotation and translation), while the month and week are based on the lunar cycle of translation around the earth in roughly 28 days. When people tried to force lunar and solar calendars to fit, we ended up with the inconsistent months we have.

The 12/60 base divisions of the day were chosen before we had good calculators. Numbers with many divisors like 12 and 60 help a lot with mental math when you don't have calculators.

There have been proposals of better calendars. The French tried something during the revolution and other people as well. The French republican calendar was:

• 1 hour = 100 minutes
• 1 day = 10 hours
• 1 week = 10 days
• 1 month = 3 weeks
• 1 year = 12 months + 5 monthless holiday

Another idea is the Cotsworth Plan:

• 1 minute = 100 seconds
• 1 hour = 100 minutes
• 1 day = 10 hours
• 1 week = 7 days
• 1 month = 4 weeks
• 1 year = 13 months + 1 special monthless holiday

I like the French Republican Calendar, but I would change it to months with 6 weeks of 5 days instead. And divide the week into 3 work days, 2 weekends. But the Cotsworth Plan is a better compromise between lunar and solar cycles.

Neither are good decimal systems. But in the end, if we want to use both the year and the day we're fucked. There's no way of having a fully decimal system. The year is approximately 365.25 days, and 365 is an awkward number. It's only divisible by 5 and 73, so it's not possible to have good divisions of it that match adequately a 10 based grid. You could abolish months and just have 73 weeks of 5 days, but I see no advantage.

We could do away with the year and just keep the day. We could do something like

• 1 miliday= 1000 microdays (1 microday ≈ 0.086 seconds)
• 1 deciday = 100 milidays (1 miliday ≈ 1.4 minutes)
• 1 day = 10 decidays (1 deciday = 2.4 hours)
• 1 decaday = 10 days (1 decaday ≈ 1.4 weeks)
• 1 hectoday = 10 decadays (1 hectoday ≈ 3.3 months)
• 1 kiloday = 10 hectodays (1 kiloday ≈ 2.74 years)

But this system would be totally misaligned with seasons, moon phases, solar cycles, etc. One could argue that those things are not as important for everyday life as they used to be, and that's true. But they're still economically important and you'd have to implement special calendars to keep track of them. It seems something like the Cotsworth or French systems make more economic sense.

Revolutionary France had decimal time for a while, but it was not popular. People liked 24 hour days and 3600 second hours

The days in a year are the actual time it takes to orbit the Sun, but that hasn't stopped people. For financial purposes there's the ISO 8601 calendar where years have 52 or 53 weeks. There are the symmetry calendars which have even quarter years and same size months (for example, each quarter is made of a 4 week month, a five week month, another four week month) with every 7 or 6 years having a leap week

But there are so many clocks that would be obsoleted by a change to time.

Well, first off, we'd need to come up with something better.

Just off the top of my head, let's say we use days as our main unit of time and then something like centi- and milli-days (and portions of milli-days) for shorter units. A centi-day is about 14 and a half minutes. A milli-day is 86.4 seconds.

But, then, so many of our other units are defined in terms of seconds. If we abandoned seconds, we'd have to come up with new units for energy, power, and any other units which are defined in terms of seconds.

So, in order to abandon seconds, we'd have to throw away the rest of the metric system and start over.

And, I suppose that's something we could do, but is it worth it?

And even if we did all that work, that wouldn't fix the fact that the time it takes to orbit the sun isn't a multiple of the amount of time a it takes the planet to revolve around its axis.

That said, there are definitely improvements we could make without wrecking the whole metric system. Daylight saving's time is ridiculously unpopular and you'd think we'd've gotten rid of it by now. I also think getting rid of time zones would be beneficial. Perhaps making all but one month the same length.

I mean, days of the year is fine as is because that matches seasonal cycles which is important for agriculture and the like. Ofcourse along the equator lunar calenders were historically used because they don't have different seasons but a calender used by everyone keeps things consistent for trade and the agricultural trade is still one of the most important things for humanity so it best remains a solar calendar.

As for time, 60 and 24 and in general multiples of 12 are great units because they can be easily divisible in many ways. This is why they were established as such in the first place, because Babylon had a big thing for what is called "extremely composite numbers" which are basically just a number that has more factors than any previous and equal to all subsequent ones (until the next extremely composite number) and all multiples of 12 (as far as I know) fall into this category. This means that units that are multiples of 12 both easily divide into each other (making it useful for changing between units) and easily divide into many other numbers making it easier to schedule a day as you have nice clean boundaries.

And when you are studying financial mathematics, there 30 days months all around, or not actually each day is counted, or wait it's only work days. For the year you can have 360 days at year, or 365 or sometimes 366. And you need to remember all that shit for tbe exams and never use it again because is the problem for the programmers to solve.

The beauty of it is that 10! seconds = 6 weeks.

You see how your fingers split into three bits? When you count them in your hand with your thumb there's 4 fingers remaining, 4*3=12.

Bc its 6k years old and used universally.

Here is my insane take:

We should use some large multiple of ten of plank units for distance measurements,

Then we can use a noticable on our scale time period in plank time units to measure time.

That way when we can set easier standards for when we meet our extra terrestrial comrades.

Republicans only want one thing and it's disgusting