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Comment by larusso | Hacker News Reader

You are right of course but also keep in mind that, and that is just my thoughts after reading, is that the French tried to implement decimal time along with the rest of what we call the metric system in the 18th century. And it was the only system people rejected. So I think the author named everything metric to make the point that if it would be part of the system a metric second would be … long. But again I could be wrong. In any case the page would also work by naming everything decimal-something. Maybe not as catchy.

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The gradian is similarly obscure, turns out 360 and 60 are nice round numbers with many handy common divisors

I don’t know the exact history, but the rest of the metric system is designed with a base unit and decimal derivatives. Assuming we want to keep the day length consistent (I can’t imagine a system being practically useful otherwise), we’d have decidays, centidays, etc. and not have hours, minutes, and seconds in the system at all. A system with days, decidays (2.4 hours), millidays (1.44 minutes), and microdays (0.0864 seconds) doesn’t seem bad to me at all, I’m sure people would come up with a good name for 10 microdays for daily use (0.864 seconds).

I never thought about this. And actually never bothered to read up on the proposed terminology. Only thing I always assumed was that the first draft of all terms is not 100% what we use today. Especially because it comes from France. But that’s only assumptions. But yes I think you are right with the naming convention.

10 microdays -> a decamicroday -> a demiday -> a dem

kDay, MDay, etc could work in space but they don't fit well with the length of the year. As long as we live on Earth we cannot escape from our planet taking about 365 days to orbit the Sun. History proved that it's convenient to have the same event (let's say start of spring) falling at the same date every year. Hence all the refactoring of calendars and leap years.

I wonder how we would settle that matter if we'll ever be able to travel fast between planets. Each city had its own time zone before trains required us to sync them because of conflicting railroad timetables. So we ended up with the current timezones. With planets, each one would have its day length and number of days in the year, maybe even inconstant seasons in the case of precession of perihelion or double star systems. I'd say we'd settle on local time and a common space time but who knows.

Every area had a mile that was a different lenght from the others. Time was the same everywhere already.

Time was the same for the people that were measuring it with the same tools.

Western sundials started with 12 hours as they worked only during the day [1] and people that were not measuring time eventually measured it with a 24 hours system.

I could not find many sources about Chinese sundials but from the pictures at [2] you can see that they had 12 hours in all the day. A hour on the second sundial is divided in 8 parts. The one in the first picture seems to have the same 8 characters as the other one but each hour is divided into 2 parts, each divided in 4 parts.

I'm not surprised that everybody settled around some small and convenient number. 12 has more factors than 10 and dividing by 2 is more convenient than dividing by 3. I would be surprised to find a 9 or a 15.

[1] https://en.wikipedia.org/wiki/History_of_sundials

[2] https://sonofchina.com/what-is-a-sundial-and-how-does-it-wor...

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