Johannes Kepler
27 Dec 1571 – 15 Nov 1630
German astronomer, mathematician, astrologer, natural philosopher, and composer Johannes Kepler also wrote about music. He played a significant role in the Scientific Revolution of the 17th century and is most known for his laws governing planetary motion as well as his writings Astronomia nova, Harmonice Mundi, and Epitome Astronomiae Copernicanae.
Kepler did not refer to his findings as “laws,” He saw them as manifestations of God’s plan for the cosmos—celestial harmonies. His discovery that the Sun actively drives the planets around in noncircular orbits, changed Nicolaus Copernicus’s Sun-centered system into a dynamic universe.
Gravitaion
Introduction Of Chapter
By this time we know that anything thrown up falls down towards the earth, going uphill is lot more tiring than going downhill, raindrops from the clouds above fall towards the earth and there are many other such phenomena which proves the tendency of all material objects to be attracted towards the earth. Historically it was the Italian Physicist Galileo who recognised the fact that all bodies, irrespective of their masses, are accelerated towards the earth with a constant acceleration.
Later on observation of stars, planets and their motion has been the subject of attention in many countries. The earliest recorded model for planetary motions proposed by Ptolemy about 2000 years ago was a ‘geocentric’ model in which all celestial objects, stars, the sun and the planets, all revolved around the earth However a more elegant model in which the Sun was the centre around which the planets revolved – the ‘heliocentric’ model – was already mentioned by Aryabhatta (5th century A.D.) in his treatise. A thousand years later, a Polish monk named Nicolas Copernicus proposed a definitive model in which the planets moved in circles around a fixed central sun. His theory was supported by Galileo .Later Johannes Kepler could discovered three elegant laws that now go by the name of Kepler’s laws. These laws were known to Newton and enabled him to make a great scientific leap in proposing his universal law of gravitation.
In this chapter we will study the theories given by these great scientists about the nature and laws of universe in detail. Also we will further study how the concepts given by them are used by modern scientists to send satellites and space ships in the universe.