A Jupiter-type comet is a comet with a period of less than 20 years and a semi-major axis shorter or roughly the same as that of Jupiter's orbit. Such comets differ from both long-period comets and Halley-type comets (the other main variety of short-period comet) in that their orbits are inclined to the plane of Earth's orbit at no more than 40°, whereas the longer-period comets enter the planetary region randomly from all directions. Jupiter-type comets are believed to have come from the Kuiper Belt.