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| Version | User | Scope of changes |
|---|---|---|
| Dec 20 2006, 7:29 AM EST (current) | sarathy88 | 4782 words added, 18 photos added |
| Dec 20 2006, 7:25 AM EST | sarathy88 |
| Sir Isaac Newton at 46 in Godfrey Kneller's 1689 portrait |
| 4 January 1643 [OS: 25 December 1642][1] Woolsthorpe-by-Colsterworth, Lincolnshire, England |
| 31 March 1727 [OS: 20 March 1727][1] Kensington, London, England |
| Physicist, mathematician, astronomer, alchemist, and natural philosopher |
Nature and nature's laws lay hid in night;//
God said "Let Newton be" and all was light.
| Early life |
| Middle years |
| Later life |
| Writing Principia |
| Religious views |
| Occult studies |
Assuming the mass to be constant, the first term vanishes. Defining the acceleration to be
results in the famous equation
which states that the acceleration of an object is directly proportional to the magnitude of the net force acting on the object and inversely proportional to its mass. In the MKS system of measurement, mass is given in kilograms, acceleration in metres per second squared, and force in newtons (named in his honour).In the year 1666 he retired again from Cambridge to his mother in Lincolnshire. Whilst he was musing in a garden it came into his thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from earth, but that this power must extend much further than was usually thought. Why not as high as the Moon said he to himself & if so, that must influence her motion & perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that supposition.[30]The question was not whether gravity existed, but whether it extended so far from Earth that it could also be the force holding the moon to its orbit. Newton showed that if the force decreased as the inverse square of the distance, one could indeed calculate the Moon's orbital period, and get good agreement. He guessed the same force was responsible for other orbital motions, and hence named it "universal gravitation". A contemporary writer, William Stukeley, recorded in his Memoirs of Sir Isaac Newton's Life a conversation with Newton in Kensington on 15 April 1726, in which Newton recalled "when formerly, the notion of gravitation came into his mind. It was occasioned by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself. Why should it not go sideways or upwards, but constantly to the earth's centre." In similar terms, Voltaire wrote in his Essay on Epic Poetry (1727), "Sir Isaac Newton walking in his gardens, had the first thought of his system of gravitation, upon seeing an apple falling from a tree." These accounts are probably exaggerations of Newton's own tale about sitting by a window in his home (Woolsthorpe Manor) and watching an apple fall from a tree. Various trees are claimed to be "the" apple tree which Newton describes. The King's School, Grantham, claims that the tree was purchased by the school, uprooted and transported to the headmaster's garden some years later, the staff of the [now] National Trust-owned Woolsthrope Manor dispute this, and claim that a tree present in their gardens is the one described by Newton. A descendant of the original tree can be seen growing outside the main gate of Trinity College, Cambridge, below the room Newton lived in when he studied there.