1. Cosmos – Part 1 Solar System Please send comments / corrections to paddy.jagan@gmail.com

2. Our early views We’ve all spent many nights looking up to the night sky and staring at stars and other objects of the sky From pre-historic times humans have had a fascination towards celestial bodies, they worshiped the Sun and the Moon, followed heavenly motions, identified seasons But humans view of the universe was guided from their point of view. It looked like they were the center of the universe and everything revolved around them and created for his purpose.

3. The mysterious heavens Soon early humans figured out that there was some order to the arrangements in the sky and everything was not random Early astronomers saw the sun, moon and planets move within a belt and identified a number of constellations within this belt The Greek astronomer Ptolemy saw the sun, moon and planets moving around the earth in complex orbits as depicted below. This theory prevailed for 13 centuries

4. Breaking Ptolemy’s theory In the 16 th century a polish astronomer by name Copernicus proposed that the sun must be in the center of the universe giving light to all the planets. But he thought that the planets followed a perfect circular orbit. But Copernicus’ theory was not accepted in those days Another astronomer Tycho Brahe from Denmark built an observatory in 1576 and designed instruments which helped future astronomers verify Copernicus’ theory

5. Enter the Telescope The Italian astronomer Galileo invented the telescope and in 1609 when he turned his instrument to the sky he saw numerous things which seemed to confirm the sun-centered copernican theory. Also another mathematician in Prague, Johan Kepler used Tyco Brahe’s measurements calculated the planets’ elliptical orbits around the sun. Kepler thus modified Copernicus’ model by moving the planets in elliptical orbits rather than the circular orbits India too was very advanced in astronomy. Jai Singh II who lived in the 18 th century built very large astronomical instruments which helped us make naked eye observations