IELTS READING S47AT3

Information Theory – the big idea

Information theory lies at the heart of everything – from DVD players and the genetic code of DNA to the physics of the universe at its most fundamental. it has been central to the development of the science of communication, which enables data to be sent electronically and has therefore had a major impact on our lives.

A. Q31 In April 2002 an event took place which demonstrated one of the many applications of information theory. The space probe, Voyager I, launched in 1977, had sent back spectacular images of Q33 Jupiter and Saturn and then soared out of the Q34 Solar System on a one-way mission to the stars. After 25 years of exposure to the freezing temperatures of deep space, the probe was beginning to show its age, Q35 Sensors and circuits were on the brink of failing and NASA experts realized that they had to do something or lose contact with their probe forever. The solution was to get a message to Voyager I to instruct it to use Q36 spares to change the failing parts. With the probe 12 billion kilometers from Earth, this was not an easy task. By means of a Q37 radio dish belonging to NASA’s Deep Space Network, the message was sent out into the depths of space. Even travelling at the speed of light, it took over II hours to reach its target, far beyond the orbit of Pluto. Yet, incredibly, the little probe managed to hear the faint call from its home planet, and successfully made the switchover.

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