Famous Astronomers: The Life of Isaac Newton

A year after the death of Galileo, an infant came into the world who was christened Isaac Newton. Even the great fame of Galileo himself must be relegated to a second place in comparison with that of the philosopher who first expounded the true theory of the universe.


Isaac Newton was born on Dec. 25, 1642, in England. His father, Mr. Isaac Newton, had died a few months after his marriage to Harriet Ayscough. The little Isaac was at first so excessively frail and weakly that people feared he would not live. The watchful mother, however, tended her delicate child with such success that he seems to have thrived better than might have been expected from the circumstances of his infancy. In fact, Isaac Newton ultimately acquired a frame strong enough to outlast the ordinary span of human life.

In 1645, Mrs. Newton took a second husband, the Rev. Barnabas Smith. On moving to her new home, she entrusted little Isaac to her mother, Mrs. Ayscough. Eventually, Isaac was sent to public school. Though initially not one of the brightest in his class, Isaac eventually rose to become the head of the school.

In his younger years, Isaac Newton found amusement in making mechanical toys and various ingenious contrivances. He constructed a carriage, the wheels of which were to be driven by the hands of the occupant, while the first philosophical instrument he made was a clock, which was powered by water. He also devoted much attention to the construction of paper kites.

Isaac Newton was only 14 when his mother became a widow for the second time. She then returned to the old family home, bringing with her the three children from her second marriage. Her means appear to have been somewhat scanty, and it was consequently thought necessary to recall Isaac from school. His mother hoped that he would now lay aside his books. It was expected that the boy would enter busily into the duties of the farm and the details of a country life.

Before long, however, it became manifest that the study of nature and the pursuit of knowledge had such a fascination for the youth that he could give little attention to anything else. Fortunately, his mother determined to let her boy’s genius have the scope it required. He was accordingly sent back to school to be trained for entering the University of Cambridge.

Isaac Newton: Life at the University
In 1660, Isaac Newton, a youth of 18, was enrolled as an undergraduate of Trinity College, Cambridge. From the outset of his college career, Newton’s attention seems to have been mainly directed to mathematics. He employed mathematics as an instrument for discovering the laws of nature.

In 1669, at the age of 27, Newton was appointed to the distinguished position of Lucasian Professor of Mathematics at Cambridge. Here he found the opportunity to continue and develop that marvelous career of discovery that formed his life’s work.

The earliest of Newton’s great achievements in natural philosophy was his detection of the composite character of light. That a beam of ordinary sunlight is, in fact, a mixture of a very great number of different-colored lights, is a doctrine now familiar to every one who has the slightest education in physical science. We must, however, remember that this discovery was really a tremendous advance in knowledge at the time when Newton announced it.


In the year 1666, Newton’s attention appears to have been concentrated upon the subject of gravitation. Whatever the myth as to how the fall of an apple first directed the attention of the philosopher to the fact that gravitation must extend through space, it seems, at all events, certain that this is an excellent illustration of the line of reasoning that he followed.

Newton argued that the Earth attracts the apple. It is plain, thought Newton, that an apple let fall from a point 100 miles above the Earth’s surface would be drawn down by the attraction and would continually gather velocity until it reached the ground. From 100 miles, it was natural to think of what would happen at 1,000 miles or at hundreds of thousands of miles. No doubt, the intensity of the attraction becomes weaker with every increase in the altitude, but that action would still exist to some extent, however lofty the elevation.

Newton then thought about the moon 240,000 miles away from the Earth. The attractive power of the Earth must extend to the moon. He was particularly led to think of the moon in this connection, not only because the moon is so much closer to the Earth than are any other celestial bodies, but also because the moon is an appendage to the Earth, always revolving around it. The moon is certainly attracted to the Earth, and yet the moon does not fall down. How is this to be accounted for?

The explanation was to be found in the character of the moon’s present motion. If the moon were left for a moment at rest, there can be no doubt that the attraction of the Earth would begin to draw the lunar globe in toward our globe. In the course of a few days our satellite would come down on the Earth. This catastrophe is averted by the circumstance that the moon has a movement of revolution around the Earth.

Newton was able to calculate from the known laws of mechanics, which he had himself been mainly instrumental in discovering, what the attractive power of the Earth must be, so that the moon shall move precisely as it does. It then appeared that the very power that makes an apple fall at the Earth’s surface is the power that guides the moon in its orbit.

It was natural to suppose that just as the moon was guided and controlled by the attraction of the Earth, so the Earth itself, in the course of its great annual progress, should be guided and controlled by the supreme attractive power of the sun. If this were so with regard to the Earth, then it would be impossible to doubt that in the same way the movements of the planets could be explained to be consequences of solar attraction.

These superb discoveries were the starting point from which Newton entered on a series of researches that disclosed many of the profoundest secrets in the scheme of celestial mechanics. His natural insight showed that large masses like the sun and the Earth and the moon, attract each other and that every particle in the universe must attract every other particle with a force that varies inversely as the square of the distance between them.

Isaac Newton made a number of significant contributions to astronomy. On Monday, March 20, 1727, he died at the age of 86. On Tuesday, March 28, 1727 he was buried in Westminster Abbey.

Ball, Robert S. (1895). Great Astronomers.