Info 'n' Activity corner

Divisions of time

Seven days-one week, four weeks-one month, 12 months - one year. You must be knowing by heart these measurements of time that you learned in the primary classes. An year is divided into months, a month into weeks, a week into days and so forth. Some of these measurements or divisions of time are based on careful observations of the movements of the sun, moon and stars. But NOT all.

It is now accepted worldwide that a day ends and another begins at the stroke of midnight.

Why should this be so? There is no scientific basis for this division. This is the division of time into days followed in Europe. We in the Indian subcontinent of Asia were forced to accept and follow this division after we came under European rule.

This is another instance of globalisation. By now, you young readers must be very familiar with this word and what it means.

This was not the accepted division of time in our country, and all over India. The day began at sunrise and ended with the next sun rise. The sun set divided time into day and night. The year is divided into 12 periods of time which we call months.

Is there a scientific basis for this? Why are these months NOT all of the same length? As you know, some months have 30 days, others 31 and one month alone has 28 days. This is why I said earlier that all the measurements of time are not based on scientific observations. We know that the year has 365 days.

Now, that is based on a scientific observation. The Earth takes 365 1/4 days to make one revolution of the Sun - that is to go round the Sun. Four quarter days add up and give us an extra day every four years, which we call a 'leap year.' Next year is a leap year.

Dividing a large number of days into periods or months, was based on observations of the Moon. The Moon's changes were easy to follow. People saw the Moon change or grew in size from a new moon to a crescent moon to a half moon and a full-moon, then it grew smaller, part by part, to a thin waning crescent, to a thin line of light in the shape of a paring of a thumb nail, and finally vanish-but to re-appear again.

The ancient Aryans of India, the Babylonians who lived in Mesopotamia (part of modern Iraq) in the early centuries and the ancient Egyptians were all keen observers of natural phenomena (happenings).

They knew by constant observation that the Moon took 29 days to complete one cycle - from new moon to new moon, or from full-moon to full moon. The actual time according to modern scientific observation is 29 1/2 days.

Take your calendar and count the number of days from one poya (full moon) day to the next. September 26 was a full moon day. The next full moon is 29 days later, on October 25, and the next, on November 23.

The Aryans, Egyptians and Babylonians who were very advanced were not the only people who divided the days into periods according to the Moon's cycle.

The Indians of the more northerly parts of America also calculated time chiefly by the moon's cycle.

They calculated a long period of time by the number of moons. The time between planting of crops and harvesting was calculated by the number of moons - two for corn, five for tobacco.

They would say that a journey to a distant place might take one or two moons. There is an English idiom 'many moons' meaning a long time.

This idiom is proof that a long, long time ago, the people of England too calculated time by the Moon. One cycle of the Moon is a month - a lunar month, a 'Chandra Maasa.' Look at your calendar. In one calendar year from January 1 to December 31 - there are 13 lunar months.

The English word 'month' means moon.

In those far off days and in some societies upto more recent times, as among the North American Indians, when one cycle of the Moon marked one period of time, the people must have felt the need for a change from the long succession of days - 29 days.

So they broke up this long period into small or shorter periods. Often the beginning or end of one period was marked by a celebration or some special event.

Next we will look at these shorter periods of time.

Sumana Saparamadu