Earth is our home. It has air that we can breathe(呼吸). It has water for us to drink. It has plants and animals that we can eat. Earth is not too hot or too cold for us. It has everything we need to live.
We are on earth, but we call see things that are not on earth. Early in the morning, we can see the sun comes up. All day, the sun seems to move across the sky. Later in the day, we can see the sun goes down. But the sun is not really moving around us. We are the ones who are moving. Every morning, we turn towards the sun. Every night, we turn away from it. Every year, we go around it. Earth is our spaceship. All of us in the spaceship are riding around the sun.
At night, we can often see the moon and stars. From earth stars look like little points of light because they are so far away. But stars are really big. A star is a great mass of burning gas. It gives off light and heat. Our sun is a star.
There are eight planets moving around our sun. Earth is the third planet around the sun. Some of the planets have moons. A moon goes around a planet just as a planet goes around a star. Earth has only one moon. Some planets have more.
