Time - the forth dimension
All our activities are related to the dimension of time besides the three visible dimension of length, breadth and depth or height. This forth dimension is not visible, it is only experienced. It is experienced because we observe that the sun’s light emerges, intensifies, mellows and disappears and reappears after an interval to repeat the same cycle. We associate the change of the intensity of heat and light from the sun at certain periods. The primitive man not only observed this phenomenon but also associated it with his own biological and physical changes. He was happy and pleasant when he found the sun rising from the east, felt uncomfortable when the sun was at its meridian and sleepy as it disappeared. His bodily needs were manifest at recognizable points, which he could relate to the position of the sun in the horizon. He realized that the length of the shining period was more or less equal to the dark period. These observations led to the invention of measuring tools. The shadow cast by a straight stick could tell him what part of the day it was. Hourglasses emptied sand or water in quantities measurable against time. When he started counting the cycle of light and darkness what we now call day and night, he found that the natural phenomena of the blooming, raining and thunder, dry weather, snow fall etc. repeated at fixed intervals as if they were predetermined. Indeed they were predetermined.
0f long it was believed that the sun traveled from east to west in the day and rested under the earth for the night and passing the night under the earth it reappeared in the east next morning. It was also observed that while maintaining its east west course it also shifted positions towards north for a period and reaching a limiting point, recoursed towards south until it reached a southern point in the horizon and steadily returned towards north. When the sun was nearer it was hot and when farther either in the south or in the north it was cooler. Thus the movement between the farthest point of north and south, known as tropics, came to be associated with seasons. Four principal seasons were recognized, spring, summer, autumn and winter. Indians were more precise with six seasons Vasantham, Greeshmam, Varsham, Sarat, Hemantham, and Sisiram. They also discovered definite relationship between the advent of the seasons and the appearance of the constellations of stars.
Yet another phenomenon observed was that the moon gradually and uniformly grew in shape from a nail like scratch to a full circular object in a period of two weeks and then depleted itself in like manner until it totally disappeared in a similar period of two weeks. On one day it was totally invisible. This waxing and waning cycle took 29 or 30 days. This natural phenomenon gave rise to the concept of month, the lunar month.
With the development of intelligence, Man observed the rising to visibility of the stars. Moon was found passing across various constellations and coming to the same place in about 27 days. The entire sky was divided into 27 constellations moon traversing each in a day’s time. The horizon was divided into 12 Sectors or Zodiac (Rasis) through which the sun traversed in a period of approximately 30 days. Moon took 2.25 days to pass through one zodiac sector. The period between two appearances of a season was counted as a year and the days taken by the sun to traverse a zodiac sector was taken as a Solar month.
Another measure of time is the week. A week has seven days. It is not a perfect deviser of either the lunar or solar month or a year. Perhaps the concept of week rose from the biblical period of creation. The naming of the days also is a mystery. May be the days were named after Man distinguished the non-blinking planets from the blinking stars. They were earlier identified by numbers like day 1, day 2 etc or the first day, the second day etc. Later they were assigned to various Greek gods as the planets were named after them.
We can now see that time measure in broader terms has been universally recognized in terms of the movement of the sun and the moon according to the regularity of their movements or appearance.
The calendar is a devise, which records the movement of the celestial bodies, stars, moon and the sun. Though predictable with reasonable accuracy the movements could not be determined with the precision in the days of yore as the knowledge was limited to physical observation. Fixed patterns were however, recognized. As the mathematical skills developed it was possible to predict the movements and the locations where these bodies would appear, with greater accuracy. And the predictions could now be done many years in advance with 100 per cent accuracy.
Let us recall that a solar year measured the return of the sun to a recognizable point in the north south route of the sun. The solar year was divided into 12 months corresponding to the zodiac it passed through. The lunar year was made to comprise 12 months representing 12 cycles of the moon waxing and waning. Origin or sanctity of the number is not only fully known although a number of theories have been put forth. One version is that within a cycle of seasons the moon makes only 12 appearances and the year can only have 12 months. For our limited purpose we will accept that a year shall have 12 months and that this is born out by the physically observed natural phenomena. We also accept the lunar month is more accurate than the solar month as the latter is based on the observation of many celestial bodies, requires complicated mathematical computation and inaccuracies occur in determining the movements. Qur’aan confirms that a year will have 12 months and that the moon determines the dates and months. So we accept it without further questions “Certainly the number of months is twelve in Allah’s Book since the day He created the Heavens and the Earth.” (9:36)
Early Calendars of Egypt and Babylon
These earliest calendars had a year of 12 months with 30 days each. Later on five extra days were added to the end of the year to make it 365 days. Greeks used a kind of lunar calendar in which three extra months were added every eight years. About 432 BC Meton discovered that 235 lunar months fitted exactly in 19 solar years.
The Jewish calendar
Before we look into the Islamic calendar it will be interesting to know what sort of a calendar was in vogue in Arabia in the dawn of Islam. The Jewish calendar relied on the moon for the months and the sun for the years. The lunar calendar in use had 12 months with 30 or 29 days alternating. Thus, Muharram 30, Safar 29, Rabiul Awwal 30, Rabiul Akhir 29, Jamadul Awwal 30, Jamadul Akhir 29, Rajab 30, Shaban 29, Ramadan 30, Shawwal 29, Dul Quaida 30, Dul Hijjah 29/30. To synchronize with the lunar cycle they invented the leap year and to synchronize with the solar year they invented a thirteenth month with 11 or 12 days.
The Julian calendar introduced by Julius Caesar in 46 BC had 12 months with 31 and 30 days in alternate months. In the non leap year February had 29 days. When Augustus Caesar became the emperor he wanted to have 31 days for the month named after him, equal to July the month named after his predecessor. Perhaps he did not bother about the earlier month named after the Greek gods but he did not want to immortalize any ruler after him. May be that is why the months are still called the numerals, Sep (7th) Oct (8th) Nov (9th) and Dec (10th) as all the months were once called before they were assigned to various gods and rulers. As three months July, August and September had 31 days now; reducing September and November to 30 and increasing October and December to 31 made a readjustment. Poor February had to be satisfied with 28 days in a non-leap year and 29 in a leap year.
Over a period of about 1600 years, it dawned on Pope Gregory, that the sun had not reached the point near the equinox where it should have been on the Easter day. It was lagging by some 10 days. After a few years’ research he found that the sun took a little less than a quarter day over 365 days every year compared to a quarter day that the Julian calendar had reckoned. He found that 365.2422 days make a year. It was therefore decided to cut back 10 days in the calendar instantly and to regulate the future centuries. Even this calendar is now found to be deficient by a few seconds when checked with the atomic clock, which measures the passages of sun more accurately with reference stellar positions.
The solar calendar has undergone numerous changes since its inception due to the inaccurate calculation of the Earth’s rotation around the sun and its sidereal movement. Events recorded at a given period cannot be correlated properly with the presently used calendar for one simple reason that the exact date of change over is not known. Further, the change occurred not one particular day but on different days, in different parts of the then known world.
The Hijra calendar
The Hijra calendar is purely lunar and is based on the dictates of Qur’aan. Qur’aan does not negate the system of time measurement, as it existed at its advent. It however rectifies the anomalies found in its use. The names of the days and the months are kept intact. The Hijra calendar is based on the historical escape of Prophet Muhammad (saw) along with his followers from Makkah to Yathrib (later Madeenathunnabi) Year 1 of Hijra commenced about 300 days after the departure to Madeena of the Prophet, i.e from the 1st Muharram of the following year.
The Hijra calendar follows the tenets of Holy Qur’aan viz, 09:36. Certainly the number of months with Allah is twelve ever since He created the heavens and the Earth” 36:39. “For the moon we have appointed positions (Manazil) till it returned like the old urjoon (withered date stalk)” 10:05 “It is He who made the sun a blazing light and the moon a shining light and He appointed phases for it that you may know the count of ages and the calculations.” In 02:189 Allah (swt) ordered the people to use the natural dates of the lunar months.
Thus the number of months is 12 and each month has 29 or 30 days. The first day of the lunar month is the day after the moon emerges from the conjunction of the sun, the moon and the earth.
Calendars both lunar and solar depend on the movement of the earth and the moon about the sun or in other words, the relative or apparent movement of the sun and the moon about the earth. As their movements follow definite paths and speed, and are repetitive over a period of measured time, they are said to follow strict natural laws of relative motion. As such their movement and position can be predicted well in advance by applying these rules and can be verified by naked eye observation. Almanacs prepared by various astronomical observatories and laboratories can be used as reference material for developing the calendar. In fact the almanacs provide more information than needed for the purpose of making a calendar.