That prospect turned me into a serious shopper for trip cancellation and interruption insurance (one policy usually covers both), a product I had always dismissed as a rip-off. Like other value-oriented consumers, I had seen no need to add several hundred dollarsâ worth of vacation insurance to the price of a vacation. Until that trip. Since then we have insured a couple of other trips, but never needed to make a claim. The only time we came close was in the wake of 9/11.
Comet Facts. Comets, like asteroids, are small celestial bodies that orbit the Sun. However, unlike asteroids, comets are composed primarily of frozen ammonia, methane or water, and contain only small amounts of rocky material. As a result of this composition comets have been given the nickname of dirty snowballs..
Jupiter-family comets and long-period comets appear to follow very different fading laws. The JFCs are active over a lifetime of about 10,000 years or ~1,000 orbits whereas long-period comets fade much faster. Only 10% of the long-period comets survive more than 50 passages to small perihelion and only 1% of them survive more than 2,000 passages. Eventually most of the volatile material contained in a comet nucleus evaporates, and the comet becomes a small, dark, inert lump of rock or rubble that can resemble an asteroid.