The message was Earth's first genuine attempt at communicating ... Astronomers aimed the radio transmission at Messier 13, a globular cluster of hundreds of thousands of stars roughly 25,000 ...

Sending electromagnetic waves into the air. In 1894, Marconi transmitted the first radio waves. The first commercial radio station to transmit audio frequencies was KDKA in Pittsburgh ...

One hundred years ago the first BBC radio transmission in Gaelic was broadcast. The 15-minute service, recorded at an Aberdeen church, was aired from a studio in the city on 2 December 1923.

The Arecibo Observatory may be no longer, but its thoughtful message continues to inspire astronomers and scholars worldwide.