1. Comets that have short orbital periods and are influenced by Jupiter's gravity.

2. The glowing cloud of gas and dust that surrounds a comet's nucleus when it becomes active.

3. The path a comet takes around the Sun.

4. The process of particles in a comet's coma gaining or losing electrons and becoming charged.

5. Frozen water present in a comet's nucleus.

6. The point in a comet's orbit where it is farthest from the Sun.

7. A narrow stream of gas and dust that is expelled from a comet's nucleus.

8. A celestial event caused by Earth's orbit intersecting a trail of debris left by a comet.

9. The point in a comet's orbit where it is closest to the Sun.

10. A region of the solar system beyond Neptune's orbit that is home to many comets.

11. A type of comet that passes exceptionally close to the Sun.

12. A long trail of gas and dust that is illuminated by the Sun as a comet approaches.

13. A device used to project the image of a comet on a flat surface for observation.

14. A bright, glowing meteor caused by a comet or meteoroid entering Earth's atmosphere.

15. The process of gases being released from a comet's nucleus as it heats up.

16. Volatile substances, such as water vapor and carbon dioxide, released by a comet as it heats up.