1862: American astronomer Lewis Swift discovers the presence of a large comet that will soon bear his name. Three days later, another American astronomer, Horace Tuttle, makes the same sighting. So this heavenly body comes down to us as the Comet Swift-Tuttle.

Based on their observations, and those of other astronomers who began tracking the comet's highly elongated orbit, it was calculated that Swift-Tuttle would make its next appearance during the 1980s. They were close. Japanese astronomer Tsuruhiko Kiuchi rediscovered the comet in 1992.



©H. Mikuz
Comet 109P/Swift-Tuttle

Aside from its unusual orbit, Swift-Tuttle is also significant as the host body of the Perseids meteor shower, one of the most prominent in the northern sky.

Oh, and there's one more thing.

Comets come and go, literally, but Swift-Tuttle's orbit is of particular interest to us earthlings since astronomers calculate that it is very likely to strike either the Earth or the moon on its next pass. They've even zeroed in on a date: Aug. 14, 2126.

We'll just have to wait and see.