page_title: Arecibo message
section_title: Humanity
hierarchical_section_title: Arecibo message / Description / Humanity
context_page_description: The Arecibo message is a 1974 interstellar radio message carrying basic information about humanity and Earth sent to globular star cluster M13. It was meant as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials.
  The message was broadcast into space a single time via frequency modulated radio waves at a ceremony to mark the remodeling of the Arecibo radio telescope in Puerto Rico on 16 November 1974. The message was aimed at the current location of M13 about 25,000 light years away because M13 was a large and close collection of stars that was available in the sky at the time and place of the ceremony. The message forms the image shown here when translated into graphics, characters, and spaces.
context_section_description: The element in the center represents a human. The element on the left (in the image) indicates the average height of an adult male in the US: 1.764 m (5 ft 9.4 in). This corresponds to the horizontally-written binary 14 multiplied by the wavelength of the message (126 mm). The element on the right depicts the size of human population in 1974, approximately 4.3 billion (which, coincidentally, is within 0.1% of the number of DNA nucleotides). In this case, the number is oriented in the data horizontally rather than vertically. The least-significant-digit marker is in the upper left in the image, with bits going to the right and more significant digits below.
caption: Part 5 — Human form, the height and population of humans
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