Isaac Newton

Biography

Isaac Newton was an English scientist and mathematician. He made major contributions in mathematics and physics (the study of the relationship between matter and energy) and advanced the work of previous scientists on the laws of motion, including the law of gravity.

Early life and education

Isaac Newton was born on Christmas Day, 1642, at Woolsthorpe, a village in southwestern Lincolnshire, England. His father died two months before he was born. When he was three years old, his mother remarried and moved away, leaving Isaac in the care of his grandmother. After a basic education in local schools, at the age of twelve he was sent to the King's School in Grantham, England, where he lived in the home of a pharmacist (one who prepares and distributes medication) named Clark. Newton was interested in Clark's chemical library and laboratory and built mechanical devices to amuse Clark's daughter, including a windmill run by a live mouse, floating lanterns, and sun dials.
After Newton's stepfather died, his mother returned to Woolsthorpe, and she pulled him out of school to help run the family farm. He preferred reading to working, though, and it became apparent that farming was not his destiny. At the age of nineteen he entered Trinity College, Cambridge, England. After receiving his bachelor's degree in 1665, Newton stayed on for his master's, but an outbreak of the plague (a highly infectious and deadly disease often carried by rats)
caused the university to close. Newton returned to Woolsthorpe for eighteen months, from 1666 to 1667, during which time he performed the basic experiments and did the thinking for his later work on gravitation (the attraction the mass of the Earth has for bodies near its surface) and optics (the study of light and the changes it experiences and produces). The story that a falling apple suggested the idea of gravitation to him seems to be true. Newton also developed his own system of calculus (a form of mathematics used to solve problems in physics).
Returning to Cambridge in 1667, Newton quickly completed the requirements for his master's degree and then began a period of expanding on the work he had started at Woolsthorpe. His mathematics professor, Isaac Barrow, was the first to recognize Newton's unusual ability. When Barrow resigned to take another job in 1669, he recommended that Newton take his place. Newton became a professor of mathematics at age twenty-seven and stayed at Trinity in that capacity for twenty-seven years.

Experiments in optics

Newton's main interest at the time was optics, and for several years his lectures were devoted to the subject. His experiments in this area had grown out of his interest in improving the effectiveness of telescopes (instruments that enable the user to view distant objects through the bending of light rays through a lens). His discoveries about the nature and properties of light had led him to turn to suggestions for a reflecting telescope rather than current ones based on the refractive (bending) principle. Newton built several reflecting models in which the image was viewed in a concave (rounded like the inside of a bowl) mirror through an eyepiece in the side of the tube. In 1672 he sent one of these to the Royal Society (Great Britain's oldest organization of scientists).
Newton was honored when the members of the Royal Society were impressed by his reflecting telescope and when they elected him to their membership. But when he decided to send the society a paper describing his experiments on light and the conclusions he had drawn from them, the results almost changed history for the worst. The paper was published in the society's Philosophical Transactions. Many scientists refused to accept the findings, and others were strongly opposed to conclusions that seemed to show that popular theories of light were false. At first Newton patiently answered his critics with further explanations, but when these produced more criticism, he became angry. He vowed he would never publish again, even threatening to give up science altogether. Several years later, at the urging of the astronomer Edmund Halley (c. 1656–1743), Newton put together the results of his work on the laws of motion, which became the great Principia.

His major work

Newton's greatest work, Philosophiae naturalis principia mathematica, was completed in eighteen months. It was first published in Latin in 1687, when Newton was forty-five. Its appearance established him as the leading scientist of his time, not only in England but in the entire Western world. In the Principia Newton, with the law of universal gravitation, gave mathematical solutions to most of the problems relating to motion with which earlier scientists had struggled.
In the years after Newton's election to the Royal Society, the thinking of his peers and of scholars had been slowly developing along lines similar to those which his had taken, and they were more open to his explanations of the behavior of bodies moving according to the laws of motion than they had been to his theories about the nature of light. Yet the Principia 's mathematical form made it difficult for even the sharpest minds to follow. Those who did understand it saw that it needed to be made easier to read. As a result, in the years from 1687 to Newton's death, the Principia was the subject of many books and articles attempting to better explain Newton's ideas.

London years

After the publication of the Principia, Newton became depressed and lost interest in scientific matters. He became interested in university politics and was elected a representative of the university in Parliament. Later he asked friends in London to help him obtain a government appointment. The result was that in 1696, at the age of fifty-four, he left Cambridge to become warden and then master of the Mint (place where money is printed or manufactured). Newton took the job just as seriously as he had his scientific pursuits and made changes in the English money system that were effective for over one hundred years.
Newton's London life lasted as long as his professorship. He received many honors, including the first knighthood given for scientific achievement and election to life presidency of the Royal Society. In 1704 he published the Opticks, mainly a collection of earlier research, which he revised (changed) three times. In later years he supervised two updated versions of the Principia, he carried on a correspondence with scientists all over Great Britain and Europe, he continued his study and investigation in various fields, and, until his very last years, he performed his duties at the Mint.

His Opticks

The Opticks was written and originally published in English rather than Latin, and as a result it reached a wide range of readers in England. The reputation the Principia had prepared the way for the success of Newton's second published work. Also, its content and manner of presentation made the Opticks more approachable. It contained an account of experiments performed by Newton himself and his conclusions drawn from them, and it had greater appeal for the experimentally minded public of the time than the more mathematical Principia.
Of great interest for scientists were the questions with which Newton concluded the text of the Opticks —for example, "Do not Bodies act upon Light at a distance, and by their action bend its rays?" These make up a unique expression of Newton's ideas; posing them as negative (incorrect) questions made it possible for him to suggest ideas that he could not support by experimental evidence or mathematical proof, paving the way for further research by future scientists.

Later years

Two other areas to which Newton devoted much attention were chronology (the science of assigning to events their proper dates) and theology (the study of religion). His Chronology of Ancient Kingdoms, published in full after his death, attempts to link Egyptian, Greek, and Hebrew history and myths and to establish dates of historical events. In his Observations upon the Prophecies of Daniel and the Apocalypse of St. John, his aim was to show that the predictions of the Old and New Testaments had so far come true.

Newton died on March 20, 1727. His surviving writings and letters reveal a person with tremendous powers of concentration, the ability to stand long periods of intense mental strain, and the ability to remain free of distractions. The many portraits of Newton show him as a man with natural dignity, a serious expression, and large searching eyes. He had developed a mathematical explanation of the universe and opened the door for further study. In changing from pursuit of answers to the question "Why?" to focus upon "What?" and "How?," he prepared the way for the age of technology (a scientific way of achieving a practical purpose).

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