1What is meant by a comet?
2Name the three main parts of a comet and say briefly how each one is formed.
3Why does a comet's tail always stretch in the direction away from the Sun?
4Write the difference between the dust tail and the ion tail.
5How does the shape of a comet's orbit affect when it can be seen?
6Compare the periods of revolution of Hyakutake and Encke.
7How is an extinct comet formed?
8Give two examples of the effect of a comet striking a planet.
9Distinguish between an endocomet and an exocomet.
10State the orbital periods of Halley, Enke and Tempel Tuttle.