© 2011 Rex Jaeschke. All rights reserved.
“What is the time now?” and “What is today’s date?” seem like straightforward questions. However, you might be surprised at the answers as you move from one “normal” context to another.
I remember well one of my first trips to Japan where I bought a ticket to ride on some public transportation in Tokyo. (This was well before the days when ticket machines “understood” a variety of languages including English.) I looked at the ticket to see if I could understand anything, and I noticed what looked like a date, but then again not! I don’t remember the exact details, but it was something like “20-IX-03”. In fact, it was that day’s date, using modern Japanese style. Specifically, it was the 20th day of September (the 9th month) in the 3rd year of the current emperor’s reign (Heisei, the name of Emperor Akihito’s reign). Being a computer nerd, I immediately saw the problem in dealing with such dates; without also knowing the emperor on which the date was based, the date was ambiguous. Now, I was quite willing to have the Japanese use Arabic numbers for days and years, and to use an era system for years, but the use of Roman numerals for months seemed odd. Is that normal? As they say, “Whatever floats your boat!”
In this installment, we’ll look at some interesting aspects of calendars, dates, and times. However, before we set out on that adventure, let me give you something to think about in the meantime. How often do leap years occur? If you think, “Dah! Every 4 years, of course!” you’d be right most of the time, but not always. We’ll revisit this question later. Oh, and by the way, not all minutes are created equal; some have more than 60 seconds.
Well now, what could be simpler than a plain old calendar? What indeed.
A solar calendar—like the one I use in Virginia—is based on the cycle of the sun, which involves the 365-and-a-bit days it takes the earth to go around the sun.
The Julian date system is simple; each day has a number 1 more than the previous day, starting at January 1, 4713 BC at noon in Greenwich, England (otherwise known as Julian Date Zero [JD0]). Fractions of days are supported, as are negative values, which indicate days prior to JD0. Whoa, who uses that system? Apparently, astronomers do, but you know how spaced-out they are!
Now one must not confuse Julian dates with the Julian calendar system, the latter being put into service by Julius Caesar (the guy who invented Caesar salads, I think) way back in 45 BC, when he retired the old Roman calendar, whose warranty had expired many years earlier. Under the Julian calendar, days were numbered from 1–365 in non-leap years and 1–366 in leap years. This allows day n in one year to be much like that same day in any other year, which makes it convenient for agricultural activities like planting and harvesting. Unfortunately, anyone wearing a Julian calendar watch quickly noted that this calendar system gains about three days every four centuries. [Don’t you just hate that when that happens? People arrived late for castle sieges, and some even missed short wars completely!]
If you look closely, the Julian system still manifests itself. Desktop paper calendars and diaries are still sold with the Julian day number shown for each day. Sometimes each day page also shows the number of days left until the end of the year (365-or-366 minus the day’s Julian number).
Sometime in 1582, Pope Gregory XIII had way too much time on his hands (as Popes often did back then), and he put into effect the—da da—Gregorian calendar. [Did he name it for his best friend Bob? No, it was all self, self, self! Poor Bob had to wait some 410 years until Microsoft named a product after him.] Anyway, at the stroke of midnight at the meridian that passed through the Vatican’s main outhouse, Wednesday, September 2, 1582 gave way to Thursday, September 14, 1582, and 12 days went missing. [Despite rumors at the time, they were not the 12 days of Christmas!] Today, much of the world uses the Gregorian calendar.
The era calendar used in Japan is a bit like a very simplified Julian date system, but not altogether quite, if you get my meaning.
It should be no surprise then that a lunar calendar involves the cycle of the moon. The Islamic calendar is lunar. Certain religious celebrations are based on the lunar cycle. For example, “Easter is a moveable feast, meaning it is not fixed in relation to the civil calendar. The First Council of Nicaea (325) established the date of Easter as the first Sunday after the full moon (the Paschal Full Moon) following the northern hemisphere's vernal equinox.” But then, you already knew that, right? As a result, Easter can fall as early as March 22 and as late as April 25.
Now while Pope Gregory may have had time on his hands, others had even more spare time, and they invented lunisolar calendars, which—yes, you guessed it—had aspects tied to both the sun and the moon. [Actually, I think these were April Fool’s pranks that simply got out of hand, much like the German language.] In fact, strictly speaking, the date of Easter is a combination of solar and lunar considerations. The Hebrew and Hindi calendars are lunisolar.
For a list of calendars used around the world, click here.
I grew up thinking that month and day names began with uppercase letters, and that each had a long form and a 3-letter abbreviation. However, that is not the case in many other cultures.
Now as to how one might write a date is wide open. In an earlier essay, I mentioned how an Australian was traveling around the US and sent me email saying she was coming to my area on 6/5. My challenge was to figure out if she meant June 5 (US format) or May 6 (Aussie format). Yes, some cultures write dd/mm/yy while others write mm/dd/yy. These days, much of my business and personal correspondence goes to an international audience. As such, I write dates as yyyy-mm-dd, using the century and leading zeros, if necessary, to be completely unambiguous. [The ordering of parts in this format is understood pretty much universally although in some cultures the dash is replaced by a slash or period.] In another essay, I commented on the proliferation of the US date 9/11 (the day the World Trade Center in NYC was destroyed) in countries that would otherwise write that date as 11/9. There are always exceptions to the rule, I guess.
In Part 1 of this series I wrote, “On what date does summer begin? In the US summer begins with the Summer Solstice, on June 20th or 21st, when the sun is furthest north. For countries in the southern hemisphere, the Summer Solstice is on December 20th or 21st. However, in some places equinoxes and solstices are considered to be in the middle of the respective season or at least some weeks after that season’s start, but never actually at their start. For example, in Australia, summer starts on December 1 and ends the last day of February.” [That’s what happened when you drink too much beer for breakfast!]
Fortunately, there seems to be general agreement around the world that there are 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a day. The differences then in writing a specific time come down to whether one uses a 12- or 24-hour time format, the hour/minute/second separator, and the set of symbols used to represent the corresponding values 1–12 or 0–23. [Although the Arabic number system is widely used around the world, it isn’t the only number system.]
I’ve lived my whole life using a 12-hour system, as in AM (ante meridiem, Latin for “before noon”) and PM (post meridiem, Latin for “after noon”). However, I have spent many months traveling in countries that use a 24-hour system. Once I got a digital watch (and now a pocket computer) that supported both systems, I changed it accordingly when I traveled. I did this partly so my watch would match transportation schedule signs at airports and train stations; I also did it to try and “get with the program”. Basically, if the locals could master such a system then why couldn’t I? After all, this was the normal way of doing things in their environment. After some years of doing this I freely admit to still getting confused by times after lunch; for example, distinguishing between 17:00 and 7 pm.
So, how does one write the 12-hour suffix? Take your pick from a.m./p.m., am/pm, AM/PM, and A.M./P.M. As to whether one puts a space between the time and the suffix is a personal choice; I use a space followed by am/pm, but remember I’m not normal. And what about the separator between the hour and minute value? Most commonly used are the colon (:) and the period (.), although some French-speaking cultures separate them with “ h “.
Although I’m a 12-hour person, that system has the anomaly that times like 12:05 are earlier than 1:05 when everyone knows that 1 comes before 12. In reality, the 12 acts as zero!
Several times I’ve visited US Government Department offices, I’ve seen analog wall clocks with 24 hours around the face (fortunately in Arabic numerals rather than Roman). That takes some getting used to; for example, what at a glance appears to be 6 o’clock is really 12 noon! There also are analog timepieces with two concentric circles; one numbered 1–11 with each number paired with an inner ring of 13–23, with 12 paired with an inner 0 or 24. And even the use of Roman numerals can cause some grief; apart from the “usual” way of writing them, alternate versions use IIII instead of IV, and VIIII instead of IX.
When I fly, there usually is a duty-free catalog by my seat. Whenever I flip through one and come across a very expensive watch, I’m amused by the fact that it can keep such accurate time, yet one can only read it to the nearest 5 minutes!
Now if you asked a good lawyer, “How many hours are there in a day?” you might get the answer, “How many do you want there to be?” And, indeed, politicians (who often have been trained as lawyers) can “stop the clock” or “extend the day”. For example, some years ago, I visited the State House in Carson City, the capital city of Nevada, and sat in on a legislative session. Afterwards, I was reading some information about the legislature. Members meet every two years and can meet up to 120 days, but they only get paid for 60 days. By law, they must conclude their business before the start of the 121st day. On a number of occasions, as midnight on the 120th day approached, it was clear that more time was needed, so the members passed a bill that extended the day by several hours, having 13 o’clock pm, then 14 o’clock pm, and so on. I have heard of other situations where the chamber clock was stopped, so, technically, the official time stood still while business was finished.
Back in the days of travel by foot or horse, one could not go large distances in short times, so one couldn’t see the impact of the earth’s rotation in relation to movement on the earth’s surface. Fast-forward to railways, and passengers needed to make connections; timetables came into being. It was no longer acceptable for each town to have its own idea of the time; some synchronization was needed. And once planes and cars arrived, it was possible to travel long distances much more quickly. And so the idea of time zones came about with the earth being divided into 24 1-hour vertical zones (called lunes), nowadays starting at the meridian running through Greenwich, England, whose zone is known as Greenwich Mean Time (GMT). [In military parlance, time zones have designated letters with GMT being “Z/Zulu” time.]
Within most countries, there is only one time zone, and in most cases, the difference between adjacent time zones is one hour. I just happen to be from a country that is abnormal. Australia has three time zones; however, the central zone (in which my hometown is located) is 30 minutes behind the eastern zone, and 90 minutes ahead of the western zone. Other countries/areas that have half-hour differences include Afghanistan, Burma, India, Iran, Newfoundland (Canada), and Venezuela. Nepal has a 15-/45-minute difference from its neighbors. I now live in the US, which spans six time zones: Eastern, Central, Mountain, Pacific, Alaska, and Hawaii, going east-to-west. Only Russia spans more time zones (10), and, in some cases, its neighboring zones differ by two hours instead of one. (Given the width of China, one might expect it to have multiple time zones as well, but it has only one.)
Summertime/Daylight Saving Time
The idea of moving clocks forward to increase the number of working daylight hours is not new. However, it is more prevalent in areas outside the tropics as tropical places already have more daylight hours even in winter. In fact, in the tropics, one doesn’t talk about seasons as summer through winter; one talks about rainy and dry seasons. This difference manifests itself in Australia. For example, Queensland and the Northern Territory (states that are in adjacent time zones) are in the tropics, and don’t have summer time. On the other hand, South Australia, New South Wales, and Victoria (among others) are much further south, and they do have summer time. In summer, you get the interesting situation in which South Australia is 30 minutes behind both New South Wales and Victoria, to its east, yet 30 minutes ahead of Queensland, which is also to the east. And Queensland is an hour behind its neighbor to the south.
And let’s not forget what my dear old mom used to say, “That daylight savings business is silly and, besides, all that extra sunlight has caused my curtains to fade!”
Back in the Good-Old Days
Back when I was in history class in primary school, I learned that the modern western calendar was based on the birth of Jesus Christ, and that dates before that were written with the suffix BC or B.C. (English for “before Christ”), while dates afterwards had the suffix AD or A.D. (anno domini, Latin for “in the year of our Lord”) or no suffix at all. [Contrary to a vicious rumor started by members of the People’s Front of Judea (or was it the Judean People’s Front?) AD does not stand for after death.] Historically, BC was written as a suffix (as in 23 BC) and AD as a prefix (as in AD 1066); however, it is now commonplace to both written as suffixes.
Apparently, not all the world is Christian—Thank God for that!—and in these politically correct times, we need a lay approach to dates from the pre- and post-whatshisname eras. So, AD became CE, which stands for Common Era or Current Era (or if you insist, Heaven forbid, Christian Era). And BC became BCE, which stands for Before the Common Era or Before the Current Era (or Before the Christian Era).
Now there is no year 0 in this system, but, when written on a time line, there is a single point that designates the change from midnight Year 1 BC to 00:01 Year 1 AD, which I am sure you are happy to know. However, the lack of a year 0 led to a huge problem that during the recent millennium change resulted in people arguing for days over when the new millennium actually began. Wikipedia (which you all know contains lies!) claims that, “most experts agree that a new century begins in a year with the last digits being "01" (1801, 1901, 2001); new millennia likewise began in 1001 and 2001. A common misconception is that centuries and millennia begin when the trailing digits are zeroes (1800, 1900, 2000, etc.); moreover, this convention was widely used to celebrate the new millennium in the year 2000.” So, those of you who celebrated in 2000 had it all wrong, but then you could do it all over again in 2001 to make up for it. Oh, by the way, at an archeological dig in the Middle East, scientists recently found documentation of a previously unknown Y1K problem. It caused absolute havoc at Cash Machines at the “Scribes and Pharisees Savings and Loan Association”, which had failed to recalibrate its abaci.
Has your life become a drag? Well if you have been paying very close attention you may have noticed that, lately, the earth isn’t rotating as fast as it used to. In reality, a day is a small fraction of a second more than 24 hours. This proved too much for some lawyers (who, apparently, bill by the millisecond), so over drinks at a bar the concept of a leap second was born. Yes dear reader, from time to time, when your back is turned, and without any warning whatsoever, an extra second is added to some unsuspecting minute, giving that minute 61 seconds. Now you might well ask, “Who is doing this?” and “How often are they doing it?” “Is it a ploy by my boss to get me to work longer without extra pay?” The simple answers are, “Bruce”, “zero, once, or twice a year”, and “Yes”.
Now for those of you having atomic clocks in your basement, this is very important to know, because you should be making leap-second adjustments from time to time (get it?). For a detailed list of when adjustments have been made in the past, click here. The adjustments are always made at 23:59:60 on June 30 and/or December 31. It doesn’t happen every year, and in some years, it happens at both times. As the earth slows down, leap seconds will need to be added on a more frequent basis. Unfortunately, unless your timepiece isn’t connected to the internet, you’ll have to adjust it manually; just push the “add leap-second button”.
Now the really good news is that the lawyers drinking at the bar that night were quite visionary. They not only allowed for the addition of an extra second, they also allowed for one’s removal. So, if the earth should ever get struck by the Mother of all Comets at a very low angle from the west, and the planet starts spinning faster, we’ll all die horribly. But we’ll die—rest-assured—that our atomic clocks will still be keeping the correct time for the cockroaches and other primitive forms of life [shame on you for thinking “used-car salesmen”] that survive the catastrophe!
GMT vs. UTC
Just when you thought GMT had been around long enough to be trusted, someone had to go and invent something else, namely, Coordinated Universal Time (UTC). GMT wasn’t good enough for him; oh no, he had a much better idea.
The good news is that unless you are intimately involved with very high-precision timepieces (e.g., atomic clocks) or highly synchronized computer networks that manipulate the world’s financial systems, you needn’t worry about UTC, which by the way was responsible for all this leap-second nonsense. [By that way, it’s actually quite surprising just how much money you can siphon off from the financial network in that extra second!]
Do you use the terms this week or next week? To understand what they mean, one needs to know what day it is today and the day of the week on which the week starts. In the latter case, there are multiple customs: many people start their week on Sunday, while others believe that Monday is the first day.
Have you ever watched a movie and thought, “When was that made?” Yet at the end of the credits, the copyright date is written using Roman Numerals, which, for films produced before 2000, makes it hard for most mere mortals to fathom. The general thinking about this is that is a deliberate obfuscation mechanism to hide the actual date, so you don’t automatically think, “This is an old [as in lame or not up-to-date] movie”.
As to the time now and today’s date, I’m sitting here in Szczecin, Poland, where it’s 15:05 and, according to the trusty Gregorian calendar next to me, it’s Piątek (Pt), Lipiec 1, 2011 [3:05 pm on Friday (Fri), July 01, 2011; that is]. According to the Um-al-Qura calendar, the date is AlJumaa, Rajab 29, 1432, whereas the Hijri/Lunar calendar says it’s a day later at AlJumaa, Rajab 30, 1432. On the other hand, the Saka era calendar says it is Sukravara, Asadha 10, 1933.
Now back to the earlier question, “How often do leap years occur?” Using the Gregorian calendar system, a leap year is one that is a multiple of 4, but not also a multiple of 100, unless it’s a multiple of 400. [Hmm, that sounds like it’s related to the Julian date system, which gained about three days every four centuries.] So, while 1600 and 2000, for example, were leap years, 1700, 1800, and 1900 were not. As such, the next leap year after 1896 was 1904, a gap of 8 years. Now go and challenge your friends and neighbors with that, if you have time, that is.