Most historical figures are known for things you can assume they were personally familiar with. Authors scribbled their books and poems, inventors whacked together their thingamajigs, and painters were intimately involved with smearing their smears. Astronomers nowadays, of course, are different — they rely on imaging from radio, x-ray, and even gravitational detectors to chart things they can’t actually see. But four centuries ago, the only tools astronomers had were telescopes, so of course they actually saw the planets, stars, moons, and assorted cosmic paraphernalia they reported on.
That’s what you’d think, at least. But Edmond Halley, who was born November 8, 1656, managed to become known for his eponymous comet — but he never saw it. It’s an interesting story.
Halley was a top scientist and England’s “Astronomer Royal,” and he sailed to the remote island of Saint Helena in 1676 to build an observatory to explore the southern celestial hemisphere. He also recorded Mercury as it moved across the sun, and realized that careful measurement of “transits” like that could lead to a way to calculate the distances in the solar system, like between Earth, Venus, and the Sun. He needed more mathematical tools, though, and when he returned to England he met Isaac Newton, who was actually inventing new mathematical tools. Halley encouraged him, and funded the publication of Newton’s Philosophiæ Naturalis Principia Mathematica in 1687.
One of the new ideas in Newton’s book was his law of universal gravitation, and Halley used it to calculate quite a few values for celestial bodies and events. In 1705 he published Synopsis of Comets, which analyzed all the known comets of the day. There was one prominent one that was known, but nobody was ever sure when it would return; it only showed up once every few decades. Halley, though, calculated that its orbit brought it within sight about every 75 years, and predicted it would be back in 1758. The comet showed up just as he said, but Halley himself didn’t live to see it; he had died in 1742 at age 85.
By odd coincidence, Bram Stoker, the Irish author of Dracula, was born on November 8 in 1847. His main character was from a castle in the forbidding mountainous landscape of eastern Europe. Even though Stoker traveled extensively, that was one area he never visited, so he never saw any spooky Transylvanian castles.
