What are satellites?
Before 1957, the word satellite meant one thing — a small body that revolved around a larger astronomical body. Today we call these “natural satellites.” In 1957, the Soviets launched the first “artificial satellite,” Sputnik 1. Today there are hundreds of artificial satellites in orbit around the Earth. These satellites are used for many purposes, such as communications, weather forecasting, and navigation, as well as observing the Earth. Satellites used to observe the Earth carry a variety of instruments to study the land, ocean, air and life, as well as their interactions. Scientists at NASA’s Langley Research Center use several satellites now in orbit to measure some very specific atmospheric phenomena, such as the amount of ozone in the atmosphere, and to help them distinguish between environmental changes caused by humans and those that occur naturally.
