UNIVERSE
Scientists believe the universe contains everything that exists. The sun, the moon, the planets, and all the stars are part of the universe. It reaches farther than scientists can see with their most powerful telescopes.
Comet
A comet travels on its own special part around the sun. its tail can be as long as 100 million miles.
Stars and Galaxies
The stars that we see in the sky at night are burning balls of gas, like the sun. They are so far away that they seem very tiny and faint. Our sun is one of a group of million of stars called the Milky Way. A huge group of stars is called a galaxy.
>This giant spiral galaxy is called the Andromeda Galaxy.
The Solar System
A group of nine known planets, including Earth, travels around the sun in a huge ring, or orbit. It is called the solar system and is surrounded by space, where there is no air to breathe and things are usually huge distances apart.
>Mercury, Venus, Earth, Mars are giant balls of rock. Jupiter, Uranus, Saturn, and Neptune orbit further from the sun and are made mostly of liquids and gases. The futhest known planet is Pluto. It is made of rock and ice.
>The sun is a star, a great ball of glowing gases which gives us light and warmth. It is many times bigger than the earth but seems small because it is millions of miles away.
>The moon orbits around the earth, not around the sun. It is much nearer to the earth than any of the stars, so it looks bigger than they do.
