English_Master March 2, 2016 No Comments
AN OVERVIEW OF THE SOLAR SYSTEM From the dawn of history until the beginning of the 17th century the known universe consists of 1. Earth 2. Sun 3. Moon 4. Mercury 5. Venus 6. Mars 7. Jupiter 8. Saturn and the ‘fixed’ stars. These are the ones that could be seen, easily without any optical instruments. In Europe, the prevailing view was the Ptolemaic system with the Earth at the centre and the other bodies revolving around it. In 1610, Galileo first turned a telescope on the heavens and the universe was explored. By the end of the 17th century, 9 new planets had been discovered and Copernicus’s heliocentric theory was widely accepted. The total number of known planets had more than doubled to 17. In 18th Century, only 5 new planets (not counting comets) were discovered, all by William Herschel, bringing the total to 22. The number of planets in the solar system increased dramatically in the 19th century with the discovery of the asteroids (464 of which were known at by 1899) but only 9 more ‘major’ planets were discovered. The number of major planets rose to 31 (almost double the 17th century). In the first three quarters of the 20th century, 13 more major planets (and...
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