Stars and Planets

When you look at the night sky, every bright dot above you may look like a star. However, a few of the dots may be planets in our solar system. You can tell which is which by watching for the movement of planets in the night sky. Stars never change position with other stars. Planets move slowly to different positions among the stars night after night. There are eight planets, including Earth, in orbit around the Sun. Five of them, Mercury, Venus, Mars, Jupiter, and Saturn, can be seen from Earth without a telescope. Planets also look different from stars. Most stars twinkle. Planets do not. The easiest way to tell a planet from a star is to see whether or not it twinkles. Unlike stars, planets do not give off their own light. They reflect starlight. Also, though you cannot see it, planets have a hard center. Stars do not.

A Venn diagram shows how two things are different and how they are alike. The features the two things have in common go in the middle, where the circles overlap. This Venn diagram compares stars and planets.View Larger Image

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