Exploring the Universe

On a bright night when you look up at the sky, it seems to be studded with stars. Little do you realize that each of the stars is far bigger than the earth on which we live. Some of the larger ones have been estimated to be many millions of times the size of the earth. The stars are not scattered regularly in space; they occur in clusters, better described as galaxies or nebulas. Each galaxy may contain as many as 100,000 million stars. The stars appear small to us even through a telescope because they are so far away. The light from the nearest star traveling at the speed of light (i.e. 299,400 kilometres/186,000 miles per second) takes something like four years to reach us. A ray of light from the sun takes about eight minutes to reach the earth. Light takes only a second to reach us from the moon. In recent years much interest has been shown and vast expenditure has been made, particularly by the United States and the Soviet Union, in exploring outer space. Many problems have had to be overcome. For example, the problem of meeting man's basic needs of oxygen, water and food; temperature control and the problem of weightlessness, while he is in outer space. A number of technological advances have been made in the course of these space programmes, particularly in the fields of radio and television communications. On 4 October 1957 the Soviet Union successfully launched the first artificial satellite (Sputnik I). This was followed by a series of unmanned spacecraft that sent back to earth television pictures of the surface features of the heavenly bodies, and coded information by radio. In April 1961 the Soviet Union successfully placed the first man, Yuri Gagarin, in orbit round the earth. Since then there have been many manned flights into outer space, culminating in the first landing on the moon by American astronauts in a rocket called Apollo 11 in July 1969. The importance of space exploration to man in general, and to geographers and other earth scientists in particular, is immense. Much has been learnt about space temperature, the magnetic fields of the sun and the earth, the amount and kinds of radiation, the shape and extent of the earth's upper atmosphere. We have learnt much about the surface of the moon and about human adaptability to its environment.