Travel to china for This comet has been observed since BC and perhaps even earlier. Its orbital period has consistently been ? years. Like long-period comets, Halley-type comets may travel around the Sun in either a prograde or a retrograde revolution. However, in general they are less steeply inclined than long-period comets. Most Jupiter-family comets are very narrowly inclined to the ecliptic and are prograde, and have orbits that are greatly indebted to Jupiter’s gravitational inluence. In short, Jupiter, acting like a pinball flipper, is able to ling narrowly inclined, prograde, longperiod comets that make close passes by it into short orbits. Thereafter the orbits of these captured comets are perturbed by frequent close encounters with Jupiter. Travel to china 2016.