Life of a Comet by Sandy Pobst

Introduction Comet –a small body in the solar system that often has a bright tail. Comet comes from the Greek word kometes.

Comets form The comets travel around the sun in a nearly circular orbit or path.

Building blocks About 4.6 billion years ago our solar system began to take shape. Frozen gas and dust began to stick together. Comets may hold the key to the history of life on earth.

Parts of a comet The mass is the center of the comet. A comet is invisible during much of its lifetime. After the comet orbits the sun it heads toward outer space once more.

Types of comets One of the most important is the length of their orbits. The two main groups of comets are long-periods and short- periods. Short-period comets can be divided into two additional groups intermediate-type of comets and comets in the Jupiter family.

Long-period comets Long-period comets begin in the Oort cloud. Long-period comets have periods lasting more the 200 years. Some periods may be longer than one million years.

Intermediate-types comets Intermediate-types comets also form in the Oort cloud. Their periods range from do to 200 years.

Jupiter family comets Jupiter family comets come from the Kuiper belt. These comets have the shortest periods of all. Scientists around the world are studying the dust particles to see what comets are made of.

Shutting down Each time a comet passes the sun. As the comet moves away from the sun dust settles back onto the comets surface. These comets look very much like asteroids.

Breaking a part Many changes take place in a comet’s nucleus it passes near the sun. These changes can create problems for the comet. As a comet circles the sun pockets of ice many change into gas.

Burning up Some comets die when the they travel near the sun and burn up. These comets are know as sungrazers.