A comet is an icy body made up of gases and dust. When it passes close to the sun, the gases produce a visible atmosphere. Sometimes, the body also produces a visible tail. Like planets, comets are in an orbit around the sun. In 1994, comet Shoemaker-Levy collided with Jupiter.

Comet Shoemaker-Levy breaking up over Jupiter (photo: NASA).

Photo: Comet Shoemaker-Levy breaking up over the planet Jupiter (Creative Commons: NASA).

Comets: Properties and Behavior

Comets are made up of an ice and dust core. The icy material is mostly water. However, it may also contain solid carbon dioxide, methane, and ammonia. The core can be up to 16 kilometers in diameter.

As comets approach the sun, the icy material is turned into a gas. The gas forms a coma (a cloud of gases). Solar radiation also produces a tail that points away from the sun. These tails can be up to 160 million kilometers long.

Comets move in an elliptical orbit around the sun. At one point in the orbit, the comet approaches close to the sun. At the other extreme, the comet may swing far beyond the orbit of Pluto. Periodic comets have an orbit less than 200 years. Other comets have orbits that are well over 1000 years. The famous Halley’s Comet has an orbit of 76 years.

Comet Smashing into Jupiter

In 1994, the comet Shoemaker-Levy collided with the planet Jupiter. It is now thought that Jupiter helps protect the inner planets from similar collisions.

If such a comet were to strike the earth, it would cause planet wide destruction. In times past, a comet striking the earth may have caused the extinction of life. The damage caused from the collision would include such things as a huge explosion, tsunamis, fires, etc. In addition, the cloud of dust would alter the earth’s climate for many years.

Video: Comet Striking Jupiter (source: YouTube).

Vocabulary Building

The following is a recommended list of words and their definitions for students.

collision: an event when one object strikes another violently.

comet: an icy body that releases gas and dust when passing close to the sun. The gases produce a visible atmosphere or coma. In some cases, it also produces a visible tail.

orbit: the circular path of an object around a star or planet.

Improving Your Reading and Thinking Skills

Think for a few moments. Try to recall the major ideas in this article. Try to answer the following questions to improve your reading comprehension.

•  How does Jupiter protect the inner planets from collistions with comets?Jupiter’s gravity helps protect the inner planets by attracting large objects

•  What kind of damage is caused when a comet collides with a planet?

•  What is a comet made of?



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4 comments on "Comet Colliding with Jupiter: First Line of Defense"

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Webster Gabiana

Ang butala at gawa ng ising ice at dust core.

Webster Gabiana

A comet is made of an ice and dust core.

Ronand Abella

Jupiter gravity maaring makatulong na protektahan sa loob ng planeta.

Ronand Abella

Jupiter gravity can help protect inner planet.