What is Time?
Every living thing is influenced by time, and since the days of early man we have accepted the passing of time as something natural and inevitable. Our early ancestors linked time directly with the position of the sun in the sky and the seasons of the year. The sun's angle of elevation (how high it stands above the horizon) was the natural way for man to estimate the time of day, and days were grouped into months according to the periodic appearance of the new moon. It is no accident that we continue to measure angles in terms of 'minutes' and 'seconds' and that our full circle contains 360 degrees.
For early man learned by experience that there were on average twelve months in a year and roughly thirty days in a month, giving a total of 360 days in a year. Sub-dividing the full circle was probably the beginning of geometry.
The reappearance of leaves on the trees and the breeding seasons of animals gave man his first indication of an annual division of time. But these signs could not be relied on, for spring could arrive early or late. Then, in the more civilized communities, it became important to know the correct time of year to sow and reap the harvest. The temple priests found they could map out the position of certain bright stars which proved better timekeepers- than the leaves of the trees.
As a result, many religious festivals were associated with some significant position of the moon or stars. Even the design of pyramids and temples was often controlled by the direction of the sun or moon's rays at these important times. Mythology, astrology, superstition and genuine scientific observation developed hand in hand, until man's fear of the unknown and the power of the priesthood took the upper hand and condemned him to an age of almost total scientific stagnation.
He emerged from these dark ages, as they are called, in the 15th century, when printing became more widespread and people began to read and educate themselves. Life became more civilized, trade flourished, and as men explored the world aids to navigation became increasingly important.
From the very early days, sailors had used the stars and the position of the sun and moon to decide the direction of their course across the sea, but they also needed to know the time before they could calculate their actual position.
Three things - time, a position on the earth, and the angle of elevation of a star- are mathematically linked; knowing two of these, the third can always be calculated. It was only in the 16th century that the influence of the navigator became more important than that of the priest in the development of machines to measure time.