Artificial satellites
1. Satellites help to develop reliable communication links between different countries separated by large distances on the globe. The communications include telephone conversations, fax messages and contact through a INTERNET. Such satellites are called ‘communication satellites'.
2. Many artificial satellites are helping to follow weather changes. With the advance information sent by a satellite about cyclones, typhoons, etc., can be avoided. Such satellites are used for the purpose of ‘weather prediction'.
3. Some satellites can see the areas of forests, deserts on the land and also areas on the ocean and take pictures. With the help of these pictures proper steps are taken to prevent deforestation and expansion of deserts.Collection of large number of fish in certain area of an ocean can be detected by a satellite. This would enable fishermen to catch the fish. Presence of minerals, ores and ground water in a region of the land in a country could be detected from the pictures sent by satellites. Such satellites are called ‘remote-sensing satellites'.
4. Satellites and space-stations are used for exploring planets, stars and galaxies in the universe. Space-shuttles sent by America also behave as a satellites. Experiments conducted in such space-shuttles and space-station promoted the growth of science and technology in the modern world. Satellites have also been used for spying by defence services of country.