The recently discovered comet comes around just once every 6,800 years.
"comet"
In Quest To Harpoon A Comet, A Spacecraft Stalks Its Prey
Tomorrow morning, a European space probe will arrive at a comet with a tongue-twister of a name: Churyumov-Gerasimenko.
If Comet ISON Survives The Sun, The View May Be Spectacular
If it manages to hold itself together after a rendezvous with the sun, ISON “could reappear in the dawn sky in early December as a potentially spectacular naked-eye object for skywatchers in the Northern Hemisphere,”