In details

Edmond halley


Although there are hundreds of comets observed throughout the ages, Halley's comet is the most talked about, it crosses the history of mankind, it is like a trace of unity, associating us with all our ancestors who contemplated it with all our descendants. who beheld him.

But who is the character whose name is attached to him? Sir Edmond halley (1656-1742) It was the London-born English mathematician and astronomer who realized that the comets observed at intervals of an average of 76 years since ancient times were the same comet because the elliptical orbit was absolutely identical to those of these other comets. . And he wrote, "I can certainly predict the return of this comet to 1758." And he added prodigiously: "Posterity will certainly not shy away from recognizing that this fact was discovered by English."

The expectation was high when 1758 arrived, and the comet does not appear. Eminent sages argue that he will not return and continue to question Newton's laws of universal gravitation that Newton's close friend Halley had a good intuition that the force that attracts a planet toward the sun decreases inversely proportional to the square. from the distance. Meanwhile French mathematicians, notably Joseph-Jérome le Français de LALANDE (1732-1807) plunge into a monk's work to recalculate the comet's positions on its trajectory according to Halley's calculations, and 6 months later reveal that "the comet was late because of Saturn and Jupiter "and warn no one to doubt, he will arrive!

On Christmas Eve in Saxe, an amateur astronomer caught him in his telescope, and was later seen from the Paris Observatory. It was the triumph! For the first time mathematics predicted the return of a comet! Halley was right. Newton's universal gravitation was confirmed. This comet will be forever named after him (Halley's comet). It appeared again as predicted in 1835, in 1910, in 1986, and will return in the year 2061…