Newton biography

A BRIEF BIOGRAPHY OF ISAAC NEWTON

I do not know what I may appear to the world, but
to myself I seem to have been only like a boy playing
on the sea-shore, and diverting myself in now and then
finding a smoother pebble or a prettier shell than ordinary,
while the great ocean of truth lay all undiscovered before me.

Isaac Newton (1642-1727)

Following Galileo, the next big scientific developments occurred in England. Although England had its religious troubles the authorities were, on the whole, much more tolerant than many other countries. Men such as Digges, who did not hide their acceptance of the Copernican system, were therefore in no danger. The heliocentric hypothesis was being taught at Oxford University by 1619 and a translation of Galileo's Dialogues was readily available in 1661. Also, Charles II, the so-called 'Merry Monarch' who was returned to the throne following the Restoration in 1660, was a strong supporter of science, and he and his friends backed the formation of the Royal Society [1].

I suppose that a great number of people when they hear the name of Newton visualize a young man sitting under an apple tree in an English garden, deep in thought, when suddenly an apple falls and strikes the man on the head. Up he jumps, "That" he exclaims, "is an example of gravity!" The story is probably not true, of course, but Newton is probably best known for his theory of gravitation. In fact, there were many people at that time who might have wished that it was an anvil that had fallen on his head rather than an apple! Newton was not a particularly pleasant man and his relations with other academics were notorious with most of his later life spent embroiled in disputes and controversies with his colleagues. Even his loyal assistant at Cambridge, William Whiston said that "Newton was of the most fearful, cautious and suspicious temper that I ever knew". As we will see, he had bitter quarrels with Robert Hooke (the founder of elasticity), with Gottfreid von Leibnitz (about the invention of the calculus), Christian Huygens (about the nature of light) and the astronomer John Flamsteed, who described Newton as:

"insidious, ambitious, excessively covetous of praise, and impatient of contradiction ... a good man at the bottom but, though his nature, suspicious."

Nevertheless, his work on motion, optics and gravitation make him arguably the greatest scientist the world has ever known.

Newton's life can be divided into three distinct periods; the first in his boyhood days from 1643 up to about 1665. The second period from 1665 to 1687 was the highly productive period, in which from 1669 he was Lucasian professor at Cambridge. The third period from the late 1680's, nearly as long as the other to combined, saw him as the elected member of Parliament for Cambridge and later, a highly paid government official in London with little further interest in mathematics.

He was born in Woolsthorpe, a small village in Lincolnshire on Christmas Day, the same year Galileo died, 1642. His father had died before he was born and he was so small and sickly that his mother said he 'could have been put into a pint pot'. He went to a local village school where he showed no particular brilliance. When he was twelve he went to the King's School, Grantham [2] where, at least initially, he had shown little promise in academic work. In fact, his school reports had described him as 'idle' and 'inattentive'. When his mother remarried in 1645 - to Reverand Barnabas Smith, the rector of North Witham - he was left in the care of his maternal grandmother, but when his step-father died in 1658 his mother removed him from school so that he might help manage the family estate. But it didn't work out so an uncle - the rector of Burton Coggles - took charge and decided the young Newton should be prepared for university and so he was sent back to school. Although he shared many of the attributes of Galileo - manual dexterity and a fondness for invention [3] - he was, in reality, very different from Galileo. The latter has been described as a hot-blooded jouster with a zest for life whereas Newton was soft-spoken recluse who was secretive about his ideas [4]. However, he was not always able to avoid conflict and it was the result of a fight at school that supposedly set off his academic achievements. According to his nephew, John Conduitt, it was sparked by the following incident:

When he [Newton] was last in the lowermost class but one, the boy next above him, as they were going to school, gave him a kick in the belly, which put him in a great deal of pain. When school was over, Newton challenged him to a fight, and they went into the churchyard. While they were fighting, the Master's son came out and encouraged them by clapping one on the back and winking at the other. Isaac Newton had the more spirit and resolution and beat him [the bully] till he would fight no more. Young Stokes [the Master's son] told Newton to treat him like a coward and rub his nose against the wall, and accordingly Newton pulled him along by the ears and thrust his face against the side of the church. Determined to beat him also at his books, by hard work he finally succeeded and then gradually rose to be first in the school.

In June 1661 he entered his uncle's old College at Cambridge, Trinity College, where his aim was get a degree in law. Instruction at Cambridge was dominated by Aristotelean philosophy; the imaginative theories of Copernicus and Kepler, and Galileo's work remained unrecognized. But in the third year of the course much more freedom was allowed for independent study. Newton studied Descartes' Geometry and became very interested in the new algebra and analytical geometry. He was also very much attracted to the mechanics of the Copernican astronomy of Galileo. Gradually his true talents began to emerge. At this point he was lucky enough to fall under the influence of Isaac Barrow, Lucasian professor of Mathematics, who quickly saw Newton's talents. He was awarded a scholarship and graduated with a BA in January 1665. However, as a result of the great plague, the university was closed in the summer of 1665 and he had to return home to Woolsthorpe. There, in a period of less than two years, while he was less than twenty-five years old, he began his revolutionary advances in mathematics, optics, physics and astronomy. While at home he conceived the idea of 'universal' gravitation, the first great inductive generalization. In his own words, recalled some fifty years later, he says

... In the same year I began to think of gravity extending to ye orb of the Moon ... and having thereby compared the force requisite to keep the Moon in her orb with the force of gravity at the surface of the Earth, and found them answer pretty nearly ... All this was in the two plague years of 1665 and 1666, for in those days I was in the prime of my age for invention, and minded mathematics and philosophy more than at any time since ...

Also he laid the foundations for differential and integral calculus, several years before its independent discovery by Gottfried von Leibnitz. Using the calculus he produced simple analytical methods that unified many separate techniques previously developed to solve apparently unrelated problems such as finding areas, tangents, the lengths of curves and the maxima and minima of functions. However, his book about the calculus, or the 'method of fluxions' as he called it, which was completed in 1671 failed to get published and did not appear until much later. He returned to Trinity College in 1667 and was elected a Fellow. In 1668 Newton received the MA degree and in 1669, when only twenty-six years old, he became the Lucasian Professor, succeeding Isaac Barrow, and he started his work on optics. Although most every scientist since Aristotle believed that white light was a single entity Newton, because he had observed chromatic aberration in telescopes - that is the coloring at the edges of images - thought otherwise. Indeed by using a simple prism arrangement he showed that white light was made up of many colors that were bent at slightly different angles to form a spectrum.

He thought that it would be impossible to correct for chromatic aberration in refracting telescopes, that is those with lenses, and so he designed and built the first, practical reflecting telescope. In 1672 he donated a reflecting telescope to the Royal Society and was elected a Fellow of the Royal Society.

That same year he published his first paper on light and color. Two influential scientists who had long spent time studying light, Robert Hooke and Christian Huygens objected to Newton's attempt to prove that light consisted of small particles rather than waves. His relations with Hooke deteriorated and he delayed publication of a full account of his researches on light in a book called Optics until Hooke's death in 1703.

His greatest achievement was his work in physics and celestial mechanics. As we have seen above, by 1666 he had begun to formulate his three laws of motion and he had also discovered the law giving the centrifugal force on a body moving in a circular orbit. Newton's novel idea was to imagine that the Earth's gravity influenced the moon, counter-balancing its centrifugal force. From his law of centripetal motion and Kepler's 3rd Law of planetary motion, Newton deduced the famous 'inverse square law'. In 1684, partially because many people were tiring of Robert Hooke's boasts [5], and also because Hooke, Halley and Sir Christopher Wren had independently developed some ideas about gravity but were unable to explain planetary motion, Newton was persuaded by Edmund Halley to write a full treatment of his new physics and its application to astronomy. After some seventeen or eighteen months of work, he duly published his Philosophiae naturalis principia mathematica (or the Principia as it is always known) in 1687 [6]. In the opinion of many scientists, the Principia is the greatest scientific book ever written. In it Newton analyzed the motion of orbiting bodies, projectiles, pendulums and free-fall near the Earth. He further demonstrated the universal law of gravitation. He explained a wide range of previously unrelated phenomena including the orbits of comets, the tides, the precession of the Earth's axis, and the motion of the moon.

While working on the Principia Newton begun to take a more prominent role in University affairs and politics, and was elected parliamentary member for Cambridge. Following a serious illness in 1693 Newton retired from research at Cambridge and took a government position in London becoming Warden of the Royal Mint (in 1695) and Master (in 1699), a position he held until his death. In 1703 he was elected president of the Royal Society and re-elected every year afterwards until his death in 1727. In 1705 he was knighted by Queen Anne, the first scientist to be so honored. His health had deteriorated to such an extent that in 1725 his duties at the Mint were carried out by a deputy. In February 1727 he presided for the last time at the Royal Society and on March 20 1727, he died in his eighty-fifth year. He is buried in Westminster Abbey. Whereas Galileo had discovered HOW things moved, Newton had discovered WHY.

FOOTNOTES

[1] Formally known as the Royal Society of London for Improving Natural Knowledge, it was founded officially in 1660. However, its members had been meeting periodically and in correspondence with one another for some years prior.

[2] He lived in the house of an apothecary.

[3] Apparently he made windmills, water-clocks, kites and sun-dials and he is said to have invented a four-wheel carriage that was moved by the rider.

[4 Even in later life the results of his experiments had to be 'pried' out of him and his contemporaries were never certain when he had actually made his discoveries. Although most of his brilliant ideas were conceived when he was between 23 and 25 years old he kept most of them secret. The full accounts were published much later; his work on gravity and mechanics when he was 44 and his work on optics when he was 65.

[5] In 1679 Hooke wrote to Newton explaining how he believed planetary motion was the result of a central force continuously diverting the planet from a straight line path. After several exchanges of letters Hooke said his own theory involved the inverse square law for gravitational attraction. Years later, Hooke was to use this correspondence to claim priority for proposing the inverse square law of gravitation.

[7] Edmund Halley decided to meet the cost of publishing the work when the Royal Society, which had become over-burdened by the costs of publication of a book on Fishes, was unable to do so.

REFERENCES

Books

M. Shamos Great Experiments in Physics (Dover Publications Inc., New York, 1987).

Web-sites

wwwcn.cern.ch/~mcnab/n/in dex.html