Monday, January 9, 2012

What's in a Calendar?

It’s not even ten days into the so called New Year 2012 and we are already burdened with a flurry of unfortunate events – locally and internationally. To name a few that sort of got my attention:

  1. Several murders right after the New Year in several parts of the city (GTA)
  2. Female journalist harassed in Dhaka while doing investigative  report in the hands of a local MP
  3. Death of several dozens of Shiite Muslims in Iraq in yet another suicidal bombing
  4. New scuffle between the West and Iran on Iran’s nuclear ambition. There are threats of sanctions and blocking Straits of Hormuz by opposing parties (US and EU vs. Iran)
  5. Many deaths and thousands desperately in need for help in South Sudan after another tribal conflict
  6. Two Canadian’s death in Mexico in the hands of miscreants

However, none of these are out of ordinary and 2012 has nothing to do with it. It’s only a number to define a time frame. Things happen all the time and there are plenty of media and analysts to report and analyze them. I feel very little need for me to add to that mass today. Instead I went on to perform a little investigation into the origin of calendar concept itself. It is a vast field but here is a very concise summary of my findings.

The motivation for most calendars is to fix the number of days between return of the cycle of seasons (from spring equinox to the next spring equinox), so that the calendar could be used as an aid to planting and other season-related activities. The cycle of seasons (tropical year) had been known since ancient times to be about 365 and 1/4 days long.
Some of the primary calendar systems are: Solar, Lunar, Lunisolar, Astronomical.

The Ancient Egyptians were the first people to make a calendar which kept in step with the Sun and the seasons. They were also the first people to use a twenty four hour clock.
Before starting to use solar calendar the earliest Egyptian calendar was based on the moon’s cycles, but the lunar calendar failed to predict a critical event in their lives: the annual flooding of the Nile River which took place at a certain time of the year.  This was due to the fact that a solar year is 365 days 5 hours 48 minutes 46 seconds long or 365.242199 days and the time between full moons is 29.53 days. Unfortunately, the cycles of lunar month and solar year did not mesh evenly. As a result lunar calendar would become out of synch of the seasons. The observant noticed that the sun moves northward and southward, through the equinoxes and solstices, as the cycle of nature in the temperate latitudes takes place. For an agricultural society, this cycle is of practical importance. Besides, it is also a good impetus for religious observances.
The Ancient Egyptians divided the day-time into twelve hours, numbered one to twelve, and the night-time into another twelve, numbered thirteen to twenty four. The hours were not all the same length: in the summer the hours of the day were longer than the hours of the night, and of course the other way round in the winter. By making all their months an even 30 days, they abandoned trying to sync with lunar cycles and concentrated instead on aligning with the solar year. However their calendar didn't quite align with a solar actual year. (30*12 = 360 days)
Eventually Julius Caesar, the Greek ruler of Egypt, asked an astronomer, Sosigenes of Alexandria, Egypt, to devise a better calendar. What resulted is called the Julian Calendar. He adopted months of 30 or 31 days length, keeping February at 28 days and introduced an extra day in February in leap years (to take care the ~.25 days per year discrepancy). Julius Caesar re-named the 5th month after himself. His successor, Augustus Caesar, re-named the 6th month after himself.
The 12 month calendar which currently serves as the world standard of time is called the Gregorian Calendar, named for Pope Gregory XIIIth who “revised” the previous Julian calendar (named for Julius Caesar). October 5, 1582 was followed by October 16th, 1582, correcting for the Julian calendar which had slipped behind the Spring Equinox by 10 days (the reason is that a tropical year (or solar year) is actually about 11 minutes shorter than 365.25 days. These extra 11 minutes per year in the Julian calendar caused it to gain about three days every four centuries, when compared to the observed equinox times and the seasons). Aside from an improved leap year calculation, Pope Gregory’s calendar has no structural differences from Julius Caesar’s calendar. The longer months were placed in the summer because the sun’s movement through the stars is slower in these months. A further correction of omitting the extra day on even century years, except every 400 years, keeps the calendar in close synchronization with the seasons.

Okay, now let’s end it on a different note. We hear so much about New Year resolution. Is it worth having? Does it make any difference whether we list out things to do in the new year or not? The answer may both be yes and no. It is always a good idea to first identify what needs to be done. So, listing them out is a good start. However, carrying them out in reality is a totally different thing. Perhaps having a long list of things that are not achievable serves no purpose. My suggestion: create a short list and work on to make them reality.

Source: Various web sites in the internet. Primarily: Wikipedia.

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