The message that inaugurated the planet Earth as a radio civilization, one hundred years ago today.
Three dots are the Morse code letter S. It was transmitted from Poldhu in Cornwall, and received by Guglielmo Marconi in a hut on Signal Hill in Newfoundland, on 12 December 1901:
It was about half past 12, when I heard three little clicks in the earphones. Several times they sounded, but I hardly dared believe. The electric waves that were being sent out from Poldhu had traversed the Atlantic, serenely ignoring the curvature of the Earth, which so many doubters had told me would be a fatal obstacle.
He had experimented with short-distance radio communication before, with one message sent the 200 km from the Isle of Wight to the Lizard Peninsula, on 23 January that year. But the transatlantic transmission, with signals bounced off the ionosphere, proved that the entire planet could be spanned.
Celebrations and reconstructions are taking place in Cornwall and Newfoundland.