I came in with Halley's Comet in 1835. It is coming again next year (1910), and I expect to go out with it. It will be the greatest disappointment of my life if I don't go out with Halley's Comet. The Almighty has said, no doubt: "Now here are these two unaccountable freaks; they came in together, they must go out together."
- Mark Twain, a Biography
(Halley's Comet is the most famous of the periodic comets and can currently be seen every 75–76 years.)