How did Halley's Comet further our understanding of the nature of comets in general?

   English astronomer Edmond Halley (1656-1742) calculated the paths traveled by twenty-four comets. Among these, he found three—those of 1531,1607, and one he viewed himself in 1682—with nearly identical paths. This discovery led him to the conclusion that comets follow an orbit around the Sun, and thus reappear periodically. In 1695, Halley wrote in a letter to Isaac Newton, "I am more and more confirmed that we have seen that Comet now three times, since the year 1531." Halley predicted that this same comet would return in 1758. Although he did not live to see it, his prediction was correct, and the comet was named Halley's comet.