Communications satellites launched by giant rockets have been in orbit around the Earth since the 1960s. On board each satellite is a radio receiver to receive signals from Earth, an amplifier to reinforce these signals, and a transmitter to send them back to Earth. All this electronic equipment is powered by solar batteries.
Television, radio, Internet and telephone conversations can be transmitted from one part of the Earth to another through any of the various communications satellites currently orbiting. A single satellite can receive and transmit thousands of telephone conversations and many television programmes all at the same time.
If, for example, the Wimbledon Tennis Tournament Championship is broadcast all over the world from England, that signal is sent from a transmitting station in England to three satellites in orbit: one over the Atlantic Ocean, another over the Indian Ocean, and the last over the Pacific Ocean. Both the land stations that send and receive the signals must point their antennas directly to the satellite so that the signal is transmitted clearly.
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