|Earth Science. McGraw-Hill, 1999.||"Sputnik 1 was an experiment to show that artificial satellites could be made. Today, thousands of artificial satellites are in orbit around the Earth."||thousands|
|World Book Millennium. Chicago: World Book, 2002.||"The Soviet union launched the first artificial satellite, Sputnik, in 1957. Since then, the United States and many other counties have developed, launched and operated satellites. Today, more than 2,000 satellites are orbiting the Earth."||> 2,000|
|World Book. Chicago: World Book, 2004.||"The Soviet Union launched the first artificial satellite, Sputnik 1, in 1957. Since then, the United States and about 40 other countries have developed, launched, and operated satellites. Today, about 3,000 useful satellites and 6,000 pieces of 'space junk' are orbiting Earth."||3,000
|Andrew P. Famous Satellites. St. Mary's HS, Manhasset, NY.||"As I mentioned earlier, Sputnik 1, which was launched in 1957, became the earth's first artificial satellite. This truly marked the beginning of the space age. There are now about 5,000 artificial satellites orbiting the earth."||> 5,000|
|Paul Butterworth and David Palmer. The Number of Artificial Satellites in Orbit. Ask a High Energy Astronomer. 1998.||"There have been about 4000 launches (some with multiple payloads) and my guess is that several hundred of the satellites involved are still active"||~ 4,000|
An Artificial satellite is a manufactured object that continuously orbits a body in space, usually the Earth. They are used for a variety of reasons ranging from studying the universe to assisting in navigation of ships and aircraft. Through these uses artificial satellites strengthen or provide communications, monitoring of crops or other natural resources,and the knowledge of weather or astronomy.
Artificial satellites usually are built to perform their function. A communications satellite for example usually is an umbrella-shaped dish like structure with multiple antennas spiking out of it. Artificial satellites remain in orbit because of the precision of the satellites velocity in reference to the gravitational force between it and the earth.
The artificial satellites were first manufactured by the Soviets in a project called Sputnik 1 in 1957. From there, artificial satellites became the phenomena they are now. They are vital structures in the development of our planet and in the future, they will play an even bigger role in our lives.
Vadim Blikshteyn -- 2004