Chapter 18 – Time

Time is so mysterious but many just take it for granted as if time has been invented by us and for us. When did time start and which part of time are we in right now? Such a question has no answer and if we think we have one, proving it would be impossible. If there’s no end to time then there might not be a beginning as well. It’s as if we being an infinitesimal part of a ring where there’s no beginning or end – just a complete circle with no breaks.

It’s year 2018 for us and we know we are somewhere in time. Cosmologists say the Universe is about 13 billion years old and the Earth is about 4 billion. So time is actually some 13 billion years old? If that is so, then we are actually in the year 13000000000 and not 2018. It can’t be year 4000000000 either because time existed before the formation of our earth. Even so, did time exist before the Universe came into being?

 

 

The human-specie thrives in a remote section of a distant galaxy among the billions and trillions of galaxies that exist. Fact is we don’t know how many galaxies there are. We only know where we are because the astronomers, astrophysicist and cosmologists tell us. They are the experts when it comes to such matters but alas know so very little.

Hence it’s is utterly forgivable for us to know next to nothing about what there is. Another fact is this estimation of 13 billion years is actually a calculated rough estimate. It’s altogether theoretical. We don’t know for sure. It may well be 100 billion years or even a trillion. We all don’t really know. Period!

We have all been born very recently in so far as time goes and aging super- rapidly as well. Who invented time? There is basically no answer because our recorded history started barely a few minutes or even microseconds ago, in contrast to and considering, the “age” of time.

We seem to know where in the Universe our planet is located but we don’t know where the parameters, if there’s any, of the Universe are. In layman’s terms, we are actually right in the middle of nowhere. Still we have no inking whatsoever where in time we are since we only began to record time, in this right in the middle of nowhere in time as well. So let’s allow our minds to try to venture a little beyond the dawn of civilization and into the dawn of humanity.

Expectedly, nascent humans would have instinctively divided the day into day and night. That’s altogether obvious since it’s a very basic division. What’s obvious too is when they could see then they could function but when it got dark it got uncomfortable for them because danger lurks in every corner. Nocturnal creatures were the lords of the nightland then. This further lends credence to our instinctive fear of the dark yet logic and confidence can overcome that in a battle between instincts and intelligence.

What’s again obvious was that they equated day time with the sun while at night they clearly saw that the lord of the sky was the moon. It would be fair to expect that very rudimentary time measurement started from there but they were more concerned about it in daily or at most yearly context given the changing seasons. They would have initially measuring time by the Sun and the Moon; and later on the stars.

It has been claimed that prehistoric people first recorded phases of the Moon about 30,000 years ago. Naturally, these have been left behind by way of depictions such as cave drawings. So, it could be even before this. They could have also observed the cyclical natural and environmental events such as seasonal rains, overflowing rivers, flowering plants, breeding along with migration of animals and birds. This was the obvious basis in dividing the year.

Shadows change direction and lengths as the sun moves across the sky. This gave impetus to the birth to sundials. However, it must have been baffling too since lengths of days do vary at different times of the year. The earth revolves around the sun elliptically and its axis tilts about 26 degrees. They also soon learned that sundials had to be specially made to suit latitudes since the Sun’s altitude decreases at higher latitudes thus producing longer shadows as compared to shadows cast at lower latitudes.

The Orion constellation is the oldest image of the star-pattern found on a chunk of mammoth tusk etched some 32,500 years ago. The symbol of Orion, by the way, is that of a man standing with a raised right arm and a sword at his belt. This can be seen at different times of the year throughout the world.

 

Orion Constellation

 

Notably, Orion was the sun god of the ancient Egyptians and Phonecians. The earliest Egyptian map of stars, some 3,500 years old, shows the conjunction of Venus, Mercury, Saturn and Jupiter in the Orion constellation; and of a solar eclipse that happened in 1534 BCE. It was known to the early Arabs as the ‘strong one’ while in parts of Africa, his belt and sword are called ‘three dogs chasing three pigs’. Orion has some of the brightest stars in the winter sky of the northern hemisphere and can also be seen in the southern hemisphere.

 

Lamassu – The Assyrian Human Head Winged Bull

 

Babylonian records on stars go way back to 1,600 BCE. They actually adopted 360 days for a year. Correspondingly, the Taurus constellation symbolized strength and fertility. It is prominently depicted in almost all mythology including Babylon, India all the way to northern Europe. This is again illustrated through the Assyrian winged man-headed bull which symbolizes the strength of a bull, swiftness of a bird and the intelligence of a man.

Already by 700 BCE the Babylonians had developed a mathematical theory of astronomy. The 12-constellation zodiac appeared sometime 500 BCE. They also introduced the 60 fraction system which is in use even today. You see it in degrees, hours, minutes and seconds. It was far easier for calculations than fractions used in Egypt and Greece. It was only after the 16th century did decimal notation begin.

The earliest archaeological evidence of Chinese calendars goes back to sometime 2,000 BCE. They show a 12 month year with the occasional 13th month. However, traditional Chinese records claim the origin of a 366-day calendar goes back as to 3,000 BCE.

By the second century it was accepted that the calendar became unreliable every 300 years. This is known as Precession and had already been recorded by Chinese historians in the fourth and fifth centuries CE. In the fifth century CE, Zu Chongzi, a scholar, created the first calendar which considered precession and took it into account. Still, the most comprehensive calendar was the Dayan Calendar of the Tang Dynasty (616-907 CE).

Precession is a phenomenon which owes its occurrence to the gradual movement of the Earth’s rotational axis in a circle and in relevance to the fixed stars. The Earth’s axis completes a circuit about once every 26,000 years. In southern Europe, Hipparchus made the earliest calculations of precession way back in 160 BCE. This was adopted by astronomers in the Middle East and India, and they recognized that precession gradually altered the length of the year. So Calendars had to be adjusted regularly.

In 325 CE the spring or vernal equinox had moved to March 21 and Emperor Constantine set dates for the Christian holidays. However, Easter was based on the date of the vernal equinox but the equinox varies every year. Then by 1582 the vernal equinox had moved another ten days hence Pope Gregory established a new calendar. This gave us an extra day in every leap year. As small changes are still accumulating, it appears that someday we would have to adopt a new calendar.

 

Roman Emperor Constantine

 

Measuring lengths of the time periods varied from culture to culture. Oil lamps have been around since sometime 4,000BCE as evidential in archaeological discoveries. The Chinese were already resorting to oil for heating and lighting by 2,000 BCE. It was therefore seen to be feasible to come to a way of measuring the oil level in measuring time. From these came marked candles used for measuring the passing of time. This came about in China in the 6th. century CE but were usually used to measure events rather than to tell the time of day.

An Egyptian sundial dating back to circa 1,500 BCE is considered the earliest evidence of the division of the day into equal parts. Alas, it couldn’t be use at night. Even then, measuring of time was of extreme importance to astronomers and priests who wished to determine the exact hour for the daily rituals and religious festivals. This soon saw the emergence of the water clock.

 

Later version sundial

 

The clepsydra or water clock was invented around 1,500 BCE. It relied on the steady flow and precise volume of water from one container flowing into another container. Comparatively, it was more reliable than the candle or oil lamp. The ingenuity lay in mitigating the variation of pressure coming from the head of water.

Su Sung, an astronomer, built an elaborate clepsydra in 1088 CE which had a rotating globe and manikins that rang gongs to tell the time. Astronomical knowledge was invaluably gained from clepsydras. China developed astronomical and astrological clock making from 200 to 1300 CE.

 

Glass-blowing was developed in the 14th century. Soon enough sandglasses started to come about. These were used in sermons and lectures. More gruesomely, it was used to monitor the duration of torture.

There is no definitive evidence on how the 24 hour day developed. Nevertheless, the fact that the day was divided into 12 hours does point to a similarity of 12 being a factor of 60. The Babylonian and Egyptian civilisations recognised a zodiac cycle of 12 constellations. During the classical Greek and Roman period, the use of twelve hours from sunrise to sunset was inspirational.

However, differing lengths of days and nights in summer and winter caused the hours to be varied throughout the year. The Tower of Winds in Athens built by Andronikos of Kyrrhestes around 50BCE was a water clock combined with Sundials positioned in the eight principal wind directions. At that time, it was the most accurate device built for keeping time.

There wasn’t a fixed length in hours until the Greeks initiated it as they needed such a system for theoretical calculations. It was Hipparchus who proposed dividing the day equally into 24 hours. This came to be known as equinoctial hours based on 12 hours each of daylight and darkness on the days of the Equinoxes. Still, ordinary folks continued to use seasonally varying hours until the advent of mechanical clocks in Europe in the 14th Century which has since become commonly accepted.

The first clock escapement mechanism was invented in 1275 with the first drawings proffered by Jacopo di Dondi in 1364. During the 14th. Century big mechanical clocks appeared in towers of numerous cities. They were weight-driven with basic problem in the period of oscillation of the mechanism – which depended heavily on the driving force of the weights and the friction in the drive. Soon more elaborate clocks were built in public places.

 

 

However and at sea, there was no device for keeping time. John Harrison though only a carpenter and instrument maker, refined techniques for temperature compensation and applied found new ways to reduce friction. With this and by 1761 he built a marine chronometer. It had a spring and balance wheel escapement and it kept commendably accurate time. His final version looking very much like a large pocket watch could determine longitude to within one-half of a degree.

Then in 1884 a conference at Greenwich reached an agreement measuring global time and Greenwich Mean Time came into being as the international standard. Today, the most accurate clocks are known as atomic clocks.

 

Atomic clock