This message, sent on November 16, 1974 from the Arecibo Observatory in Puerto Rico, consisted of 1,679 bits of information, which is divisible by two prime numbers -- 73 and 23 -- which suggest laying out the message in those dimensions, revealing this image.
The picture shows our chemical makeup, our population, our height, our planetary system, and the telescope transmitting the message.
The message was aimed at the M13 globular cluster; it will reach its destination in about 25,000 years.
More about the Arecibo Observatory:
National Astronomy and Ionosphere Center,