Tami Hirschauer, age 10, of Sioux City, Iowa, for her question:
HOW WERE THE PLANETS NAMED?
Planets and stars look much alike in the sky at night, but there are two ways you can tell them apart. First of all, planets shine with a steady light because they reflect sun light while stars seem to twinkle. Second, the planets change their positions in relation to the stars. The ancient Greeks first noted this and named the objects planetae, meaning wanderers.
Nine large objects traveling around the sun are called planets. Going outward from the sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
We live on one of the planets. Six of them are bright enough to be seen from earth with the naked eye. A telescope is needed to find Neptune and Pluto.
Mythology provided us with the names of the planets. The ancient theory suggested the earth was the center of the universe with the sun and other planets traveling around it. In 1543, however, a Polish astronomer named Nicolaus Copernicus came up with the correct theory that the earth and other planets traveled around the sun.
Mercury, the smallest planet and also the one closest to the sun, was named for the messenger of the gods, and the god of roads and travel in Roman mythology.
Venus, known as the earth's twin because it is about the same size, was named for the Roman mythology goddess of love and beauty who also symbolized the creative force that sustains all life.
Mars is the only planet whose surface can be seen in detail from the earth. It was named after the god of war in Roman mythology.
Jupiter was the king of gods and the ruler of the universe in Roman mythology. The planet with this name is the largest in the solar system.
Saturn was named after the god of fertility and planting in Roman mythology while Uranus took its name from the god who played a part in the myth which explained the separation of the earth from the sky.
Planet Neptune was named for the god of the sea in Roman mythology while Pluto was named to honor the god of the dead.
There may be another distant planet or two beyond Pluto. Astronomers aren't sure. But they are almost certain that most of the stars in the universe have planets of their own traveling around them. There are more than 100 billion stars in the galaxy that includes the sun, and over 100 billion other galaxies can be seen in the universe.
If one star in every galaxy had one planet like the earth, and intelligent life existed on one of every million of these planets, then would be 100,000 planets with intelligent life.