Newtons Law of Universal Gravitation

Discovered by : Sir Isaac Newton

Discovered in year : 1687

Gravitation is the force of attraction between all masses in the universe; especially the attraction of the earth's mass for bodies near its surface. Since the gravitational force is experienced by all matter in the universe, from the largest galaxies down to the smallest particles, it is often called Universal Gravitation. Sir Isaac Newton was the first person to discover Gravity. He described and explained his discovery through his theory which is known as 'Newton's Law of Universal Gravitation'. According to the theory 'Every object in this universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between their centres.

History

Sir Isaac Newton was an English physicist, mathematician and astronomer. The discovery of Newton's Law of Gravitation is generally based on a famous story that Newton came up with the idea for the law of gravity by observing an apple fall on his head. Though this is not true but he did wondered if the same force at work on the apple was also at work on the moon. During 1679, Newton was studying gravitation and its effect on the orbits of planets, with reference to Kepler's laws of planetary motion. He also exchanged brief letters in this regard during 1679-80 with Robert Hooke who was a natural philosopher, architect and polymath. The appearance of a comet in the winter of 1680/1681, stimulated his interest even more towards discovering the law of gravity. After the exchanges with Hooke, Newton worked out a proof that the elliptical form of planetary orbits would result from a centripetal force inversely proportional to the square of the radius vector. Newton communicated his results to Edmond Halley and to the Royal Society in De motu corporum in gyrum, a tract written on about 9 sheets which was copied into the Royal Society's Register Book in December 1684. This tract contained the nucleus that Newton developed and expanded to form the Principia. The Principia was published on 5 July 1687. He used the Latin word 'Gravitas' (weight) for the effect that would become known as Gravity and defined the law of universal gravitation.

Development in the Discovery of Newtons Law of Universal Gravitation

There were certain problems with Newton's theory and certain things needed to be explained. However there was no development in this regard until 1915. General Relativity or the General Theory of Relativity published by Albert Einstein in 1915 explained all the shortcomings and elaborated on unexplained aspects of Newton's Law. The geometric theory of gravitation by Albert Einstein in 1915 forms the current description of gravitation in modern physics. It unifies special relativity and Newton's law of universal gravitation, and describes gravity as a geometric property of space and time, or spacetime.

Role of the Discovery Newtons Law of Universal Gravitation in the improvement of Human Life

• Newton's Law enabled the general public to become aware of the forces of nature about which they were ignorant

• It led to a better understanding of the world, especially the space

• It formed the basis of study for further studies in this area, like Einstein's Theory of Relativity