You're aboard spaceship Earth

You're aboard spaceship Earth

The shuttle is blasting off into space.

The shuttle carries a crew of six. For a week the shuttle will be their home in space. On board they have all the things they need to stay alive and healthy. They have food. They have water. And they have oxygen. Oxygen is the gas that our bodies take from air when we breathe. Once they are in space, the crew cannot stop somewhere for a snack and a cold drink. They cannot open the windows for some fresh air. They cannot get more of anything. Whatever they need must be on board. off into space.

Someday you may rocket into space. But right now you are aboard a different spaceship. You have been aboard it all your life. This spaceship's name is Earth. Earth is your home in space. It is home for every person in the world. We are all aboard the same spaceship. Earth is one of nine planets that travel around the sun. Every day Earth travels 1, 608, 000 miles through space. It whizzes along at 67, 000 miles an hour. Because we are aboard Earth, we too are whizzing through space.

Like the shuttle crew, we can't make stops. We can't get more of anything. But Spaceship Earth has everything we need to stay alive. It has food. It has air with oxygen. It has water. Earth has had the same water for billions of years. Plants, animals, and people all use it. Yet Earth doesn't run out of water, because the same water is used over and over again--it is recycled.

Most of our water comes from the oceans. Water is drawn into the air by the sun's heat. It becomes a gas called water vapor. Salt from the ocean water is left behind. Water vapor forms clouds. Rain clouds drop their water on the earth. Some of it falls in the oceans. Some falls on land. There much of the rainwater runs off into streams. The streams flow into rivers. And the rivers flow back into the oceans. Again the sun's heat draws water out of the oceans. Water vapor forms clouds. It falls again as rain.