We celebrate today the centenary of a feat that was thought to be impossible. On December 12th, 1901, a 27-year-old Italian astounded the scientific world by sending a radio signal over a distance of 2,000 miles from Cornwall to St John's in Newfoundland. The event marked the beginning of the age of wireless telegraphy, which was to transform the world in just a few short years.
Gugliemo Marconi had been exploring the possibilities of radio for quite some time. At home in Bologna he began by sending messages from his house to a receiver in the back garden, and by 1895 he had succeeded in transmitting his signals over distances of a mile or more.
But the Italians showed no interest. He therefore moved to Britain in 1896, where the far-sighted Postmaster-General of the time, William Preece, saw the potential of radio as an exciting new means of communicating over long distances. He provided the young genius with moral support and the financial means to carry on his work.
The result was the Cornwall experiment 100 years ago today. An aerial 164 feet high was set up at Poldhu on the Lizard, and on the other side of the Atlantic a kite took an aerial to an even greater height. At 1800 GMT, Poldhu began to transmit the three dots of the letter S in Morse code at five-minute intervals, and faint but clear signals were detected almost immediately on the other side of the Atlantic.
And why did this so surprise the scientific world? Well, it was known at the time that radio waves travelled in a straight line, and therefore in normal atmospheric conditions reception should not be possible much beyond the horizon.
The answer to the mystery was provided in due course by Oliver Heaviside, who deduced the existence of a layer of charged particles high up in the atmosphere, a phenomenon today known as the Heaviside layer. It acted like a giant mirror, reflecting the radio waves back down to Earth and allowing them to be picked up at great distances from the original transmission point.
Marconi's work on wireless telegraphy won him the Nobel Prize for Physics in 1909. By then he had already opened the first transatlantic public wireless service, sending routine messages from Clifden, Co Galway, to Cape Breton in Nova Scotia. Indeed Marconi turned out to be a shrewd and very successful man of business; having protected his invention by the celebrated patent No 7777 of 1900, he went on to exploit its commercial potential, and the company he founded was to dominate the wireless world for many years to come.