The Arecibo message consists of several sections designed to teach alien beings that the land is inhabited and who are their inhabitants. Encrypted in binary code and must be built for interpretation. At the beginning of the message, the numbers from one to ten are in binary code, followed by chemical elements and nucleotides that transmit aliens to the nature of human THEN. Here is a display of the human being, the solar system and the observatory from which the message was sent.
Sending a message is often criticized in retrospect. Scientists such as Stephen Havkins pointed out that extraterrestrial life forms, if they received such a message, could pose a threat to the planet. After all, the discovery of America for autochthonous people living there did not turn out well.