Wednesday, October 24, 2007

COSMOLOGY: AN ANCIENT CONCEPT

COSMOLOGY: DELVING INTO THE MYSTERIES.
BY
DR.NITISH PRIYADARSHI

The Universe or the cosmos, as conceived today, consists of millions of galaxies. The Universe is infinite, both in time and space. The human conception of the Universe has, however, been different at different times over the long span of history of civilization. It was around 6th century BC that man started enquiring into the mysteries of the Universe in an endeavour to rationally analyze the earthly and the heavenly phenomena. They posed to them several questions. What is the Universe? Why things change? Why do things move? What is life? And so on. These questions were of far-reaching significance to the development of modern science.
All ancient civilizations made observations, often with astonishing accuracy, on the objects in the sky and their behavior. The position of the planets were recorded with respect to the backdrop of the fixed stars, which, fortunately, never seemed to change position and therefore provided a perfect grid for plotting planetary positions. That keen interest in the motions of the celestial bodies was prompted by the common belief that these bodies ruled human events. Ancient astronomy was in fact astrology. It remained astrology through the Renaissance. Kepler himself believed in astrology and drew up horoscopes for his sponsor, the emperor Rudolf and for the potentates at Rudolf’s court.
The Universe is now expanding. It will slow down, stop, and then collapse over itself in giant cosmocrunch, some 100 billion years in the future. All particles will collapse into a “singularity”, a point of extremely high (perhaps infinite) density and extremely high (perhaps infinite) temperature.
How and when did the Universe come into existence? We do have an idea of when (between 10 and 20 billion years ago), but how is the another story. In the ancient, unmechanised world of hunters and gatherers there was virtually no contact between region and tribes. Explanations of the earth and the heavens-fanciful primitive cosmologies-were devised by the people in every part of the world and transmitted orally from generation to generation. Such conceptions were at first almost wholly religious, and it was only with the invention some 3500 or 4000 years BC that it became possible to record observations and thus to begin the long journey toward scientific understanding of the Universe.
The Assyrians and the Sumerians, the inhabitants of Mesopotamia made the earliest recorded astronomical observations. At early development was the recognition of certain star patterns, the constellations, which serve as readily recognizable signposts in the sky. Another contribution of these early astronomers was the recognition of the twelve signs of the zodiac. Since the sun spends about thirty days in each of these visions, the transition to the concept of a twelve-month year was easy and most inevitable.
Sumerian astronomers were the first to divide the circle into 360 equal parts; the so-called degrees of the arc still in the universal use. Aside from their observations the Sumerians believed that the earth was the center of the Universe and was floating on the ocean.
Neither the Egyptians nor the ancient Hebrews advanced much beyond astrology in their cosmologies. The Egyptians believed the Universe to be kind of rectangular box oriented from north to south, like the valley of Nile, with Egypt situated at the center of the upper surface. The ancient Jews believed that the earth was flat and supported on the stones.
Meanwhile, in the Far East the Chinese were developing cosmologies essentially unrelated to those of the Mediterranean world. Chinese astronomers started recording observations of comets as early as the seventh century BC, building archives that have been invaluable to western astronomers. The most famous observations is perhaps the description of the sudden appearance of a “guest star” on 4 July 1054, which was so bright that for three weeks it was even visible in the daytime. The phenomenon was actually the supernova explosion that produce the Crab Nebula.
In “Bhagavad-Gita”(Hindu holy book), according to Jefferson Hane Weaver in his book “The world of Physics”, God is portrayed as eternal and all powerful. God is the great creator who began and will one day end the Universe. According to the Hindu calendar, as recorded in the ancient books of Vedic philosophy, the year AD 1977 corresponds to 1,972,949,078 years since the present world came into existence. According to a famous geologist, Arthur Holmes, this astonishing concept of the earth’s duration has at least the merit of being of the right order.
Cladius Ptolemaus, generally known by the Anglicized form of his name Ptolemy, lived in Alexandria, Egypt, in the second century AD. From 127 to 141 he was active as an astronomer, gathering the mathematical data that served as the basis for the most detailed geocentric cosmology ever formulated. Ptolemy’s cosmology was prompted by his conviction that the Universe must be spherical because only the sphere is perfect. He decided that stars must move in circles for the same reason. According to Hebrew document, God’s first creation was not heaven and earth but light that is, photons-a view that must delight all supporters of the “Big Bang” theory or hypothesis.
In 1543, Polish astronomer Copernicus argued that the Sun, and not the Earth, was the centre of the Universe.
In 1650 Bishop James Ussher, an Irish clergyman, published Annals of the Old and New Testaments, a volume in which he demonstrated to his own satisfaction that creation occurred at precisely 9.30 on the morning of 28 October 4004 BC That day must have been Monday because the Sabbath, when God rested, was seven days later. Stephen Hawking, the noted British cosmologist, disagrees with Bishop Ussher. Like most cosmologists today, Hawking is convinced that the Universe came into existence between time 0 and the following trillionth of a second about fifteen billion years ago.
The conception of the Universe was further widened in the 19th century when the British astronomer, Herschel, came out with his observation that the Universe was not limited to the solar system, but it was must vaster than that. The solar system, according to Herschel, was only a small part of a much bigger star system, called the galaxy.
Efforts are continuing to unfold the mysteries of the Universe, several new galaxies have been discovered, but many million others remain undetected so far.

Nitish Priyadarshi
Geologist
And Fellow Member of Geological Society of India
76,circular road,
Ranchi-834001,Jharkhand,
India.
Tel.No.- 091-0651-2562909, 2562895
Post a Comment