1. In the word perihelion, "peri" means close. What do you think the "ap" in aphelion means?
2. What is the period of a comet?
3. Do you know another name for the earth's orbital period? (Hint: think of the calendar.)
4. What is a long period comet?
5. How long can the period be for a long period comet?
6. How are short period comets different from long period comets?