World Book at NASA for Students
The sky is the part of space we can see from the Earth. At night, the sky is dark. On a clear night with no clouds, we can see the moon and stars. During the
day, we can see the sun.
When we look at the sky, we look at the atmosphere, the air that surrounds the Earth. Clouds float in the atmosphere and sometimes cover the sky. Smoke, dust, and chemical waste also may fill the sky.
When the sky is clear, it looks blue. Sunlight contains all the colors of the rainbow. When the sunlight comes through the atmosphere, blue light scatters the most and reaches all parts of the sky, making it look blue. At sunrise and sunset, sunlight must travel farther through the atmosphere than when the sun is overhead. Most of the colors of light are scattered, but the red light is not scattered. This makes the sun and the sky near it look red or orange.
How to cite this article: To cite this article, World Book recommends the following format: "Sky." The World Book Student Discovery Encyclopedia. Chicago: World Book, Inc., 2005.
When we look at the sky, we look at the atmosphere, the air that surrounds the Earth. Clouds float in the atmosphere and sometimes cover the sky. Smoke, dust, and chemical waste also may fill the sky.
When the sky is clear, it looks blue. Sunlight contains all the colors of the rainbow. When the sunlight comes through the atmosphere, blue light scatters the most and reaches all parts of the sky, making it look blue. At sunrise and sunset, sunlight must travel farther through the atmosphere than when the sun is overhead. Most of the colors of light are scattered, but the red light is not scattered. This makes the sun and the sky near it look red or orange.
How to cite this article: To cite this article, World Book recommends the following format: "Sky." The World Book Student Discovery Encyclopedia. Chicago: World Book, Inc., 2005.
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