Incredibly, there have been several changes in information communication.
Only a few hundreds of years ago, the fastest way a piece of news could travel was to be carried by a person on horseback.
Messages sent overseas could only travel as fast as the fastest sailing ship.
Breakthrough came in communications with the invention of electric telegraph and messages in Morse Code. The message was sent down a wire in bursts of electric current.
Today, however, images of written documents, sound recordings or television pictures can be flashed around the globe in less than a second by means of satellites and radio communications.
Several satelites, in different orbits, are required to give coverage over the whole globe, and different satellites are used to reflect signals for different media, such as telephone messages and television pictures.
Mobile phones work by using low-powered microwaves to send and receive messages to and from a base station.
Otherwise known as a cellular phone, a mobile allows calls to be receives and made whenever the caller happens to be.
A great amount of communication these days is carried out via satellites. Radio, telephone and television messages are transmitted around the world with incredible speed.
Such satellites orbit the Earth so that they appear to be in the same place all the time – even though the Earth is spinning round.
This is possible because a satellite’s orbit speed is matched with the Earth’s rotational speed. These are known as geo-stationary orbits.
Why are optic fibres so useful in communication?
An optic fibre is made of fine strands of glass, along which pulses of light can travel.
Light travels much faster than electricity and it is therefore used in optical cables to carry communication for very long distances without electrical interference.
The light travels along tiny glass fibres, usually packed into huge bundles capable of carrying many thousands of messages at the same time.
When you talk on the telephone your voice is turned into laser light signals and sent down very thin fibre glass tubes called optical fibres.
Optic fibre is also used for ornate lighting. Light is reflected down thousands of tiny glass fibres as can be seen on some modern artificial Christmas trees.