Isaac Newton was just 14 when Edmund Halley, who was destined in after years to become Newton’s dear friend and one of his most illustrious scientific contemporaries, was born. Halley’s fame, great as it certainly was, would have been even greater still had it not been somewhat impaired by the misfortune that he had to shine in the same sky as the unparalleled genius Newton.
EDMUND HALLEY: A BIOGRAPHY
Edmund Halley was born at Haggerston in the parish of St. Leonard’s, Shoreditch, on Oct. 29, 1656. His father, who bore the same name as his famous son, was a soap-boiler in Winchester Street, London. He had conducted his business with such success that he accumulated an ample fortune. Although there are very few particulars about Halley’s early life, we do know that he showed considerable aptitude for learning and he also had some capacity for mechanical invention.
Halley seems to have received a sound education at St. Paul’s School. Here, the young philosopher rapidly distanced his competitors in the various branches of ordinary school instruction. His superiority was, however, most conspicuous in mathematical studies. As a natural development of such tastes, he had already made good progress in astronomy by the time he left school.
At 17, Halley entered as a commoner at Queen’s College, Oxford. Though his studies were somewhat diverse, Halley’s favorite pursuit was astronomy. His earliest efforts in practical observation were connected with an eclipse that he observed from his father’s house in Winchester Street. It also appears that he had studied theoretical branches of astronomy so far as to be familiar with the application of mathematics to somewhat abstruse problems.
Up to the time of Kepler, philosophers assumed that the heavenly bodies must revolve in circles and that the motion of the planet around the orbit that it described must be uniform. The youthful Halley, however, demonstrated that, so far as the empty focus was concerned, the movement of the planet around the orbit though so nearly uniform was still not exactly so. At the age of 19, he published a treatise on the subject that at once placed him in the foremost rank among theoretical astronomers.
Halley: A Survey of the Stars
Halley had no intention of being merely an astronomer with his pen. He longed to engage in the practical work of observing. He saw that the progress of exact astronomy must depend largely on the determination of the positions of the stars with all attainable accuracy. He accordingly determined to take up this branch of work.
The fact that Halley concentrated on this work shows the scientific wisdom of the young astronomer.
Halley, however, found that the astronomer Hevelius, at Dantzig, and Flamsteed, the Astronomer Royal at Greenwich, were both engaged on work of this character. He accordingly determined to direct his energies in a way that he thought would be more useful to science. He resigned to the two astronomers the investigation of the stars in the northern hemisphere, and he sought for himself a field almost entirely unstudied.
He determined to go to the southern hemisphere to measure and survey those stars that were invisible in Europe, so that his work would supplement the labors of the northern astronomers. He hoped the joint result of his labors and theirs might be a complete survey of the most important stars on the surface of the heavens.
At the age of 20 in 1676, he accordingly set sail with his instruments for the island of St. Helena, which he had selected as the scene of his labors. On his return to England, Halley prepared a map that showed the result of his labors. He presented it to the king in 1677.
Halley found that a comet had been recorded on several occasions at intervals of 75 or 76 years. He concluded that these several apparitions related to the same object, which was an obedient vassal of the sun performing an eccentric journey round that luminary in a period of 75 or 76 years.
To realize the importance of this discovery, remember that before Halley’s time, a comet, if not regarded merely as a sign of divine displeasure or as an omen of disaster, had at least been regarded as a chance visitor to the solar system, arriving unannounced and unscheduled.
A supreme test remained to be applied to Halley’s theory. The question arose as to the date at which this comet would be seen again. We must observe that the question was complicated by the fact that the body, in the course of its voyage around the sun, was exposed to the incessant disturbing action produced by the attraction of the several planets.
The comet therefore, does not describe a simple ellipse as it would do if the attraction of the sun were the only force by which its movements were controlled. Each of the planets solicits the comet to depart from its track, and though the amount of these attractions may be insignificant in comparison with the supreme controlling force of the sun, the departure from the ellipse is quite sufficient to produce appreciable irregularities in the comet’s movement.
At the time when Halley lived, no means existed of calculating with precision the effect of the disturbance a comet might experience from the action of the different planets. Halley exhibited his usual astronomical sagacity in deciding that Jupiter would retard the return of the comet to some extent.
Had it not been for this disturbance, the comet would apparently have been due in 1757 or early in 1758. Because, however, the attraction of the great planet would cause delay, Halley assigned for the date of its re-appearance either the end of 1758 or the beginning of 1759. Halley knew that he could not himself live to witness the fulfillment of his prediction, but he said: “If it should return, according to our predictions, about the year 1758, impartial posterity will not refuse to acknowledge that this was first discovered by an Englishman.”
This was, indeed, a remarkable prediction of an event to occur 53 years after it had been uttered. The way in which it was fulfilled forms one of the most striking episodes in the history of astronomy. The comet was first seen on Christmas Day, 1758, and passed through its nearest point to the sun on March 13, 1759. Halley had then been lying in his grave for 17 years, yet the verification of his prophecy reflects a glory on his name that will cause it to live forever in the annals of astronomy.
The comet paid a subsequent visit in 1835, and its next appearance came in 1910.
After making a number of great contributions to astronomy, Halley died on January 14, 1742, at the age of 86.
Ball, Robert S. (1895). Great Astronomers.