With “standard” vs. metric measurements (and all the specialty measurement units), and the multiple calendars cultures across the world uses, how the heck did the entire world agree to the current units of time (seconds, minutes, hours, etc.) as we know them? For that matter, how did you get dozens of sovereign nations to agree to the concept of time zones?
While I know that clock time measurements are much more important, in a way, than calendar time measurements, it still strikes me as remarkable that in a world of strife and disagreement, that you got every civilized government on the globe to tow one line, no matter what that line is. Since all the calendars now in use evolved from different cultures, I find it remarkable that NO culture in the history of man had a different way of measuring time than the others, came up with a way to measure it that’s different from what we use now, and stuck with it, like Islam or the Chinese do with their calendars.
Can anyone give me the Straight Dope here? (Silly question, yes, but I’ve always wanted to ask that.)
I’d wager that minutes and seconds became international standards due to a similar need for standardization in sea navigation, but I don’t have a cite.
Using twelves and multiples thereof is a Babylonian thing. They apparently thought twelve a beautiful number because it has so many factors or possibly because twelve is the rough number of lunar months in a year. The measurement of time by mechanical means was so far advanced in the west and it’s system so advantageous compared to others that like the Arabic numerals it supersceded older systems when it came into contact with them. Calendars were kept because there is no clear advantage to the western calendar and indigenous versions had social significance.
Time zones is an even more extreme case of the ascendancy of western science, it came about as a by product of navigation, a science in which the west was unapproached.
As a side note navigation and geographical knowledge is why it is correct in at least one sense to say Columbus or one of his contemporaries discovered America,(there is debate about who first realized the land was another continent) because the other people who were there or who had been there didn’t have any idea where they were relative to everything else. You only have a rock unless you can tell it’s a diamond.
Not 100% sure here, but i remember reading somewhere that the standardization is not the 24 hour clock, but the 60 minute hour. 60 is divisible by 1, 2, 3, 4, 5, 6, 10, 12 15, 20, 30, & 60 whereas 100 (which seems to be the basis for metric measurements) is divisible by 1, 2, 5, 10, 20, 25, 50, & 100. Once the hour was set, it was simply a matter of figuring how many hours are contained in the period of 1 day. The 60 minute hour (or, by extention the 24 hour day) is not 100% accurate, thus the leap day (generally) every 4th year.
The French (among others) came up with a metric time system during the French revolution (when the French revolt, they go all the way). The best site I found describing the system is this one.
Universal-time.org is promoting their own version of metric time called UTC. They discuss other time systems as well, such as astronimical systems Solar Time and Sidereal Time.
Then we’ve got the Swatch .beat time system (click on Internet Time, then Information), an Internet time system dividing the day into 1,000 “.beats”. It’s designed to rid ourselves of those nasty time zones. A single time, say @979 (when I wrote this), means the same time to everyone all over the world (no compensation is necessary). If I understand their definition that is.
The answers so far have it down mostly. I will summarize somewhat and add some parts.
First of all it’s indeed not really 24 hours; it’s 12 hours times two. The 24-hour system was a military development in the early days of remote communication. I suppose that some rather pedantic officer got pissed when his artillery support started firing twelve hours after the actual attack and inflicted some so called friendly fire on the own forces in the newly won ground instead of the enemy that was there twelve hours earlier. Once introduced the “We meet at 14 hundred hours,” sounded so martial and efficient that they just couldn’t stop. Or maybe it was in fact that it made some incredible sense in keeping things clear… what do I know. In any case, eventually digital watches came along and it just made more sense to have 24 hours on those rather than 12 x 2 and much of the world adopted the 24-hour system (that the US still hasn’t is quite ironic since it was the US army that made the 24 hour system popular).
I guess that the OP then wants to know why it’s twelve hours? Well the decimal base has not always been the king of numeral systems, others were in use in parts around the Mediterranean way before Archimedes and the boys made water clocks and even before the Egyptians worked out that obelisks not only make really nice garden decorations, but also eminent sundials. At first the obelisks where used to show the seasons by measuring the length of the shadow they cast at noon, but eventually the sundials where routinely given divisions into hours for the rest of the day. Whether they just went ahead and used some division derived from the twelve parts of the zodiac already applied to the hours of the night, or if they decided to use the decimal system plus one hour for dusk and one for dawn adding up to twelve is contested. In whichever case the date for this development is 1500 BCE.
What is really remarkable if you think about our modern obsession with being on time is that the precise hour of the day was not really kept track of until mechanical clocks made timekeeping more reliable in the early Middle Ages. It would be several hundred years after this that minutes where measured by everyman, and seconds have only become important with the event of modern sports and the fright of Taylorism and the infamous time studies. Precise minute and second calculation was achieved by the Englishman John Harisson as a part of discovering how to create timepieces capable of remaining reliable enough to help calculate longitude, which was calculated based on difference of when actual noon takes place in comparison to Greenwich or the zero meridian - nowadays we have satellites, but we still measure geographical position in the minutes and seconds system.
Be all that as it may… it isn’t until the mechanical clock comes around that time keeping is made universal anywhere. The inventors of the mechanical clocks where probably Italian and the Egyptian time keeping standard had been prevailing for a few thousand years in that region, so it was quite natural for them to continue on that path. As these clocks spread across the world the 12-hour system came with it.
So what about those 60 minutes to the hour and 60 seconds to the second? As stated earlier it’s the Babylonian’s fault. The fairly straight forward answer can be found at NIST The National Institute for Standard and Technology where you will also find a link to a brief history of timekeeping.
All of that still doesn’t explain why Americans insist on speaking Latin several times a day instead of just saying what time it is.
Time zones were accepted mainly for trains, and then for (relatively) high-speed international travel in general. In travel at the speed of trains or higher, minutes become very relevant in determining travel times and, by extension, arrival times, departure times, and (most importantly) when certain areas of the rails are safe to travel and which areas will bring you into violent argument with the 5:15. If every town along the route is keeping its own time by defining noon as when the sun is directly overhead, and so keeping clock time absolutely synched with sun time, you’ll have major problems. So having everyone agree on the minutes is pretty much essential.
The hours are fungible, however, and herein lies the basic compromise the time zone system is based upon: Minutes are standardized for the travel system, but hours are variable for the human elements. We like having the sun rise at around 0600 and set around 2000, regardless of where we are in the world. So we have the hours vary in a predictable way in a half-attempt to keep them, if not the minutes, synched with the sun. Keeping clock time in synch with sun time makes sense if a significant portion of the population farms, which was true when time zones were devised.
It’s no longer true in the developed world. In America, less than two percent of the population farms. That means we’re saddling ourselves with a confusing, obsolete system simply for the benefit of two percent of the population and blind, ignorant inerta. If we were at all rational, we would completely decouple our clocks from sun time and just switch over completely to GMT. But no, who listens to the intelligent people?
I don’t think that makes any sense at all. The day was divided into 24 periods. The division is exact (whatever that means–the equation of time makes the Sun appear at noon at slightly different times throughout the year, see analemma.com), and the subdivisions into minutes (first minute part, with minute pronounced my-NEWT) and seconds (second minute part) follow the old Babylonian practice of base 60. The Earth is slowing down, and as a result we’ve had to define the day as the length of an average day in the year 1900–so we have to insert leap seconds every so often (actually, there has been a surprising lack of leap seconds over the last few years).
But there is no connection between 24 hour days or 60 minute hours, and leap years.
Indeed. As I noted in my previous post the division of the day into 2 x 12 hours precedes the 60-minute and second division with over one millennium. Hence it would rather be the complete reverse than that the Babylonian sexagesimal system gave the 12-hour division as proposed. The Baylonians started with the ‘Ra-given fact’ that the day has 24 hours and then applied 60 to that. Magically 12 divides into 60 as well, but there is no evidence that the Egyptians used a sexagesimal base. The most plausible explanation for a division into twelve from the site that I meant to link to earlier (with link corrected):
This isn’t exactly GD so I don’t want to start some huge discussion up, but I must disagree with your point that GMT/UTC should prevail globally. I think there is much sense in keeping to a time zone based system as of yet. Things like blue laws and the prevailing work customs makes it useful to have a system where the time of day follows the natural order of solar day. OTOH I disagree with imposed work and opening hours and I am saying all this while getting ready to go to bed at CET 05.56 (Ante Meridiem) and personally I couldn’t care less if the digits up in the corner of my screen showed UTC 04.56 instead, and maybe it would be more practical in some ways if it did so although I disagree for practical reasons it’s a good point you make.
RM Mentock, Thanks for clearing up my misconceptions. I guess i was way off on my supposition that the hour dictated the day. I still think that the hour was set at 60 minutes because of the number of ways that 60 can be divided, but i may be way off on that too. If you have any info on this, i’d appreciate it.
For that matter, how did you get dozens of sovereign nations to agree to the concept of time zones?
There is a bit of time zone craziness around the world.
All of China (which should span five time zones) uses a single time zone
In Russia, all of their time zones have been advanced an hour from what they should be, on some sort of permanent Daylight Saving Time.
Australia has 3 time zones - the middle of which is a half-hour ahead of its designated time zone.
Several countries in the Middle East and South Asia also utilize half-hour time zones.
There are even a few that are 15 minutes off: Nepal and Chatham Islands to name a couple.
Originaly the day was divided in 12 parts, and the night in twelve. The (diurnal) hours were indeed longer during summer than during winter. That didn’t matter (much) for the Babylonians, as they’re pretty close to the equator, but further north it gets important.
This was kept up through the middle ages by the church, and even the first mechanical clocks were calibrated at sunrise.
If you read anything about medieval monastic life, you will find out that the prayers were to be said so-and-so many hours after sunrise, or after noon.
The idea of starting to count from midnight, and having fixed-length hours probably arose independently, when the accuracy of mechanical clocks started to improve. (Anyone got a cite?)
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No, but there are leap seconds!
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