Day: November 16, 1974

The first transmission from Earth designed to be a message for interstellar listeners is broadcast from the newly-refurbished Arecibo Radio Telescope in Puerto Rico. Weighing in at 210 bytes, the message is a binary transmission that, when properly assembled, provides a graphical representation of Earth’s solar system, a human being, the makeup of human DNA and the elements from which it is constructed, and the population of Earth. Though the Arecibo dish is pointed in the direction of the M13 globular cluster at the time of the message’s transmission, that cluster will have moved in the 25,000 years it takes for the message to reach that location (and, in any case, Earth and its entire solar system will have moved in the 25,000 additional years it would take to receive a reply), so the message is more of an interstellar technology demo than a message in a bottle.