Comets

Comets are small celestial bodies that orbit the Sun. They are made up of ice, dust, and rocky material and are sometimes referred to as "dirty snowballs" or "icy mudballs." Comets have highly elliptical orbits, which means they can spend most of their time in the distant outer regions of the solar system before swinging in close to the Sun.

Structure of Comets

A comet consists of several parts:

• Nucleus: The solid core of the comet made up of ice and rocky material.
• Coma: The fuzzy envelope of gas and dust that surrounds the nucleus as it heats up from the Sun's radiation.
• Tail: The bright, visible tail that forms as gas and dust are swept away from the coma by the solar wind and radiation pressure.

Composition of Comets

Comets contain various ices, such as water, carbon dioxide, ammonia, and methane, as well as silicate and organic compounds. When a comet approaches the Sun, the heat causes these ices to sublimate, creating a coma and tail.

Study Guide

Here are some key points to remember about comets:

1. What are comets made of?
2. Describe the structure of a comet.
3. What causes a comet's tail to form?
4. Why do comets develop a coma as they approach the Sun?
5. How do comets differ from asteroids?

Understanding comets and their characteristics can provide valuable insights into the formation and evolution of the solar system.