I for one would love to have metric time. Just today I had to add some durations together to get total duration, which would have been simple thing to do with metric time.
Of course for practical use using SI second wouldn't be very good solution. Traditionally second is derived from the length of day, and I think that would make sense for metric time too. 1 milliday would be somewhat close to 1 minute and 50 millidays (or maybe half deciday) would be close to one hour. Of course the name probably should be something else than "day" to reduce confusion.
So I could be working something like 16 decidays next week.
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 like your point. And I do agree that a 100000-second day would be awesome, but I tried to switch to new time measurements _without_ having to redefine anything. A second is still a second. A day is still a day. I've only added a definition, the myriasecond (myria- being the 10000 prefix) and removed two definitions, the minute and the hour.
In the context of the metric system, the problem is that the second and the 'day' don't line up. From a human time keeping point of view, days and fractions of days would be ideal.
However, actual days are nowhere close to a fixed amount of time. And for historical reasons we are stuck with a very precisely defined second that is based on 24 hours in a day.
So the obvious approach would be to define a new unit of time that is roughly equivalent to a milli- or microday.
But the chance of that happening is close to zero.
So we are stuck with the second as the fundamental unit of time. Having a 'centiday' as 864 seconds would be even more removed from the principles of the metric system than a 3600 second hour.
While metric time has some appeal, I think it is not ambitious enough.
Base 10 is not good. 10 just does not have enough factors, so we are left to deal with complex fractions. Let's instead use base-12 numerals and keep time unchanged!
In base 12, 1 year is 10 months (or 265 days), 1 day is 20 hours, 1 hour is 50 minutes and a minute is 50 seconds.
Easy enough!
Edit: wait! I just realized this is still not ambitious enough!!!
What we need is to halve seconds in two. So, in base 12: 1 day = 10 hours, 1 hour = 100 minutes, 1 minute = 100 new seconds.
Instead of changing the definition of second, it might make sense to separate day-time from scientific time. Decimal hours and minutes would be normal time keeping. If needed more accuracy, then would switch use centi-minute for casual use or second for scientific use.
One nice feature is that the day-time would be different on other planets. There would Mars-day and Mars-hour. But the second would be the same.
Probably not a good time to propose decitime, I guess. (No pun intended.)
Day is the basic measure.
Deciday = day/10. (=~ 2.4 hour)
Centiday = day/100
Either could be used in place of the old fashioned hour.
Milliday = day/1000 (=~ 84 seconds)
Milliday seems like a good replacement for the traditional minute.
Centimilliday to replace seconds? It's a but unwieldy but could be abbreviated as cmd (similar to the commonly used 'sec.')
Years are a little troublesome. However with sufficient energy input a Kiloyear could be made to be 3 years. With sufficient precision (and perhaps occasional correction) it could resolve that leap year and occasional leap second issue.
There would be some ramifications. For example the Newton is defined in terms of seconds so there are some units beyond pure time that would also require revision.
Let's get rid of this madness of 24 hours, 60 minutes and 60 seconds. And 365.2425 days was just plain wrong from day 1.
How wonderful would the world be if we had a base 10 clock instead of 24?
Let's make a day be 86400 seconds (already a SI standard), and then you can divide that into tenths, hundreds or whatever. One thousand of a day is 84.4 seconds, which is close to a minute (which is (/ 60 (/ 24 one-day))).
We have metric for measurements in space, but something as simple for day-to-day time measurement would be nice.
I've always thought that if we are redefining time units a better solution might be 100000 metric seconds in a day (making them a bit shorter than the existing 86400 in a day) and otherwise the same relationships you've suggested:
What makes the metric system appealing is that each physical quantity has exactly one "base" unit, and you can make easy conversions– just multiply or divide by 10.
The thing about time is, there are two important 'natural' units that aren't going away: the day and the year. Whatever system you devise has to include them somehow. And unfortunately, the conversion factor between them (365) isn't a multiple of 10.
That said, we can do a lot better than the status quo. Since we've already given up on the idea of having a single base unit for everything, why not express time in fractions of days instead of multiples of seconds? Counting time up to 1.0 days is a lot more intuitive than counting up to 8.64 myriaseconds. The second is a unit of time which isn't tied to anything intuitive (actually, it's entirely arbitrary). If we're going to shake things up, let's at least use days instead, yeah?
It seems to me, you'd need to redefine the second such that there is a nice round number of them in a day. Say 100,000 to the day. They you could subdivide into hectoseconds (new minute, 86.4 old seconds), kiloseconds (14.4 old minutes), myriaseconds (tenth of a day, 8640 old seconds). Noon would fall on a nice even boundary.
(Of course, this ignores the fact that the day length is not constant, but we have that problem with the present system, too.)
The myriasecond would be the new, lower-resolution hour, much as the Celsius degree is lower-resolution than the Fahrenheit. This would be mitigated by writing decimal times (e.g., 3.75 myriaseconds on the clock would correspond to 9 am).
You'd also need to come up with less clunky names than myriasecond, I would think.
Edit: Why it'll never happen: Redefining the second would screw up too many things other than time of day references. E.g., frequencies and other physical measurements based on the second.
I'd say that for time, the second is the only thing people can really relate to. With a bit of practice everybody can count seconds. We cannot related to minutes, hours, day, etc. without an external time keeping source.
The other thing worth point out is that, though we have centi-, deci-, deca-, and hecto- they get only limited use in practice.
Very few distances are specified in deca- or hectometers.
Very few things are decagrams. There is a metric ounce and pound. But hectogram is not used.
So for distance, we have meter, kilometer. For mass, gram, kilogram, metric tonne.
Within the same system, we could easily deal with kiloseconds and megaseconds.
As far as I know, nobdy uses deciseconds as something other than a weird way of saying 100 milliseconds.
In informal speech, the number of zeros is used as estimate of precision. Using prefixes to specify precision is way too confusing.
Within the metric system, 10 kilosecond would roughly be the same as 3 hours. With a single day, everybody could easily adapt to kiloseconds. The problem starts when you have to create a system of timekeeping based on metric second.
No! Even better! "Metric time" - a minute has 100 seconds, an hour 100 minutes, a day is 10 hours (100,000 seconds). Makes perfect sense on a space station so we'll have to face it sooner or later.
I've read enough science fiction based on this principle that I'm semi-comfortable with kiloseconds, megaseconds, and gigaseconds (roughly a quarter hour, a tenday, and a third of a century, respectively). I'm not sure what the "myria-" prefix really adds to the mix.
The people that are objecting on the grounds that it doesn't fit the "natural" unit of the day (or month, or year) are missing the point: metric is all about picking units regardless of any convenient lineup to anything, and then applying them to everything anyway. As a matter of usage, most people take this concept even further and always count from the next smaller unit even if the larger one is closer: thus you rarely hear of "half litre" but rather "500 mL", not "quarter metre" but "25 cm" or "250 mm". Basing metric time on seconds makes vastly more sense from this perspective.
Sci-fi writers, most notably Vernor Vinge, have played with Metric Time [1] of the modern sort of being entirely second-based.
It's interesting because it particularly exposes interesting flaws in using metric prefixes (that are sometimes also talked about in the world of grams where kilograms are the closer unit to most "human applicability" and that a more human scale would possibly have more prefixes near kilogram than gram). Particularly the magnitude jump from a kilosecond (16.7 minutes, about a quarter hour) to megasecond (11.6 days, nearly a fortnight).
I've heard fun proposals that if Metric Time based on seconds were to be more useful on human timescales to bring back the deceased Metric prefix myria- [2]. A myriasecond is 167 minutes or just less than three hours (2.78). Maybe a prefix for the next digit as well (10^5) which would be just more than a day, by about an eighth of a day (27.8 hours).
Of course for practical use using SI second wouldn't be very good solution. Traditionally second is derived from the length of day, and I think that would make sense for metric time too. 1 milliday would be somewhat close to 1 minute and 50 millidays (or maybe half deciday) would be close to one hour. Of course the name probably should be something else than "day" to reduce confusion.
So I could be working something like 16 decidays next week.
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