The Role of Astronomy

On a dark, cloudless night, at a distant location far away from the city lights, the starry sky can be seen in all its splendour (Fig. 1.1). It is easy to understand how these thousands of lights in the sky have affected people throughout the ages. After the Sun, necessary to all life, the Moon, governing the night sky and continuously changing its phases, is the most conspicuous object in the sky. The stars seem to stay fixed. Only some relatively bright objects, the planets, move with respect to the stars. The phenomena of the sky aroused people’s interest a long time ago. The Cro Magnon people made bone engravings 30,000 years ago, which may depict the phases of the Moon. These calendars are the oldest astronomical documents, 25,000 years older than writing. Agriculture required a good knowledge of the seasons. Religious rituals and prognostication were based on the locations of the celestial bodies. Thus time reckoning became more and more accurate, and people learned to calculate the movements of celestial bodies in advance. During the rapid development of seafaring, when voyages extended farther and farther from home ports, position determination presented a problem for which astronomy offered a practical solution. Solving these problems of navigation were the most important tasks of astronomy in the 17th and 18th centuries, when the first precise tables on the movements of the planets and on other celestial phenomena were published. The basis for these developments was the discovery of the laws governing the motions of the planets by Copernicus, Tycho Brahe, Kepler, Galilei and Newton. Although space probes and satellites have gathered remarkable new information, a great majority of astronomical observations is still Earthbased. The most important observatories are usually located at high altitudes far from densely populated areas. One such observatory is on Mt Paranal in Chile, which houses the European VLT telescopes. Astronomical research has changed man’s view of the world from geocentric, anthropocentric conceptions to the modern viewof a vast universe where man and the Earth play an insignificant role. Astronomy has taught us the real scale of the nature surrounding us. Modern astronomy is fundamental science, motivated mainly by man’s curiosity, his wish to know more about Nature and the Universe. Astronomy has a central role in forming a scientific view of the world. “A scientific view of the world” means a model of the universe based on observations, thoroughly tested theories and logical reasoning. Observations are always the ultimate test of a model: if the model does not fit the observations, it has to be changed, and this process must not be limited by any philosophical, political or religious conceptions or beliefs.