суббота, 17 марта 2012 г.

The origin and main stages of development of astronomy

Astronomy is one of the oldest sciences. The first records of astronomical observations whose authenticity is beyond doubt, refer to the VIII century. BC But we know that even in 3000 BC. Oe. Egyptian priests noticed that the flooding of the Nile, to regulate economic life of the country, attacked soon after before sunrise in the east appeared the brightest of the stars, Sirius, hiding until then about two months in the rays of the sun. From these observations, the Egyptian priests fairly accurately determine the length of tropical year. In ancient China over 2000 years BC apparent motion of the sun and moon were so well understood that the Chinese astronomers could predict the onset of solar and lunar eclipses. Astronomy, like any other science, arose out of human needs. Nomadic tribes of primitive society had to be guided in his wanderings, and they learned how to do it on the sun, moon and stars. The primitive farmer was in the field work to take into account the different seasons of the year the offensive, and he noticed that the change of seasons linked to the midday sun in height, with the advent of certain pas the night sky of stars. Further development of human society created a need for measurement of time and chronology (the preparation of calendars.) All this could give, and give observations on the movement of heavenly bodies, which were conducted at the beginning without any tools were not very accurate, but it met the practical needs of the time. From these observations, and there was a spider on the celestial bodies - Astronomy. With the development of human society to put forward all of the new astronomy and the new tasks for which needed better ways of observation and more precise methods of calculation. Gradually began to create a simple astronomical instruments, and developed mathematical methods for processing the observations. In ancient Greece, astronomy was already one of the most advanced sciences. To explain the apparent motions of planets, the Greek astronomer Hipparchus, the largest of them (II cent. BC), created a geometric theory of epicycles, which formed the basis of Ptolemy's geocentric system of the world (II cent. AD). Being a fundamentally incorrect, the system of Ptolemy nevertheless possible to predict the approximate position of the planets in the sky, and therefore satisfied to a certain extent, the practical needs for several centuries. Ptolemy's system of the world ends with stage of development of ancient Greek astronomy. The development of feudalism and the spread of Christianity led to a significant decline in the natural sciences, and the development of astronomy in Europe slowed down for many centuries. In an era of dark ages, astronomers engaged in only by observations of visible movements of the planets and the coordination of these observations with the accepted geocentric system of Ptolemy. Rational development of astronomy in this period was only from the Arabs and the peoples of Central Asia and the Caucasus, in the writings of prominent astronomers of the time - Al-Battani (850-929 gg.), Al-Biruni (973-1048 gg.), Ulugbek (1394-1449 gg .), etc. During the period of emergence and the emergence of capitalism in Europe, which replaced the feudal society, began the further development of astronomy. Especially it has developed rapidly in the era of great geographical discoveries (XV-XVI cc.). The rising new class of bourgeoisie was interested in the exploitation of new lands and fitted out many expeditions to open them. But the long journeys across the ocean called for more accurate and simpler method of calculation of orientation and time than those that could provide a system of Ptolemy. The development of trade and navigation is strongly required to improve the astronomical knowledge and, in particular, the theory of planetary motion. The development of productive forces and the demands of practice, on the one hand, and the accumulated observational data - on the other, paved the way for a revolution in astronomy, and produced by the great Polish scientist Nicholas Copernicus (1473-1543), who developed his heliocentric system, which was published a year his death. The doctrine of Copernicus was the beginning of a new stage in the development of astronomy. Kepler in the 1609-1618 years. were discovered laws of planetary motion, and in 1687 Newton published a law of universal gravitation. The new astronomy was able to study not only visible, but the actual movement of celestial bodies. Its numerous and brilliant achievements in this area culminated in the middle of the XIX century. the discovery of Neptune, and in our time - the calculation of the orbits of artificial celestial bodies. Next, a very important stage in the development of astronomy began relatively recently, from the middle of the XIX century., When there was a spectral analysis was applied, and photography in astronomy. These methods have enabled astronomers to begin to explore the physical nature of celestial bodies and to expand the boundaries of the investigated area. There astrophysics, in particular received a great development in the XX century. and continues to flourish today. In the 40's. XX century. began to develop radio astronomy, and in 1957 was the beginning of a qualitatively new methods of research, based on the use of artificial celestial bodies, which later led to the emergence of a new section is actually Astrophysics - X-ray astronomy (see § 160). The significance of these achievements in astronomy can not be overestimated. Launching satellites. (1957, USSR), space stations (1959, USSR), the first human flight into space (1961, USSR), the first landing of humans on the Moon (1969, USA) - a landmark event for all mankind . They were followed by delivery of the lunar soil to Earth, landing landers on the surface of Venus and Mars, sending automatic interplanetary stations to more distant planets of our solar system.

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