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Graphic: Arne Nordmann
A color visual interpretation of the digital signal in the Arecibo message, sent in 1974 from the Arecibo Observatory. Broadcast into space via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope in Puerto Rico, the message consisted of 1,679 binary digits, approximately 210 bytes, transmitted at a frequency of 2,380 MHz. It was aimed at the Great Globular Cluster in Hercules, some 25,000 light-years away, and contains information related to mathematics, chemistry, and astronomy.