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.
What is a Comet? A comet is a very small solar system body made mostly of ices mixed with smaller amounts of dust and rock. Most comets are no larger than a few kilometres across. The main body of the comet is called the nucleus, and it can contain water, methane, nitrogen and other ices. When a comet is heated by the Sun, its ices begin to sublimate (similar to the way dry ice âfizzesâ when you leave it in sunlight).
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.