Edmond Halley (1656-1742) saw his namesake comet when he was 26 years old. If you were around in 1986, you might remember the excitement surrounding the return of Halley’s Comet. Halley’s Comet hadn’t been seen since 1910, and 76 years later, it was getting ready to make another pass by Earth. Many who were excited probably wound up feeling a little disappointed. I’ll admit I was. I was sixteen, and was eager to see a bright ball in the sky with a burning tail lighting up the night. All we got to see was a small, faint, comet-shaped light in the sky. It turned out that in 1986, the comet passed when the Earth was on the other side of the sun, so there wasn’t much to look at. We knew it was coming, though. We’ve known this since 1705, when Edmond Halley predicted the comet would return on Christmas night, 1758. Halley died in 1742, so he never got to see that he was correct—but he was correct. Halley’s calculations show that the comet will pass by Earth every 74 to 79 y