The message of Arecibo is a radio message which was transmitted towards space at the time of a ceremony to mark the transformation of the Radiotélescope of Arecibo in 1974. It was sent towards the globular cluster M13 which is with 25.000 light-years and consists of 1679 binary numbers. The number 1679 was selected because it is the product of two prime numbers and cannot thus be divided that of 23 lines and 73 columns, or 73 lines and 23 columns. That supposes that those which could read it will choose to arrange it like a quadrilateral. The arranged information in the first manner brings a nonsense whereas if it is arranged second way, the image contains information in connection with the Earth and of humanity. If one reads from left to right, it shows the numbers from one to ten, the atomic numbers of hydrogen, carbon, nitrogenizes, oxygen and phosphorus, the chemical formulas of sugars and bases in nucleotides of the DNA, the numbers of nucleotides in the DNA, the structure out of double-propeller of the DNA, a sketch of the human being and its size, the population of the Earth, our solar system, and an image of the radio telescope of Arecibo with its diameter.

Because the message will spend 25.000 years to reach the desired destination (and as much with a possible answer to return to us), the message of Arecibo was more one demonstration of the technological advance of the man that a real test to come into contact with a extraterrestrial civilization.

The doctor Frank Drake, who went then to the Université Cornell, creator of famous the equation of Drake, wrote the message, with the assistance inter alia Carl Sagan.

Explanations

Numbers

While reading from left to right, numbers 1 to 10 appear in binary format (the line of bottom shows the beginning of each number).

Even by knowing the binary system, the encoding of the numbers does not seem completely obvious, because in the way in which they were written. To read the first six numbers, by being unaware of the line of bottom, they should be upwards read by taking the three binary numbers of bottom. Numbers 8,9 and 10 are a little different on the right since they comprise another column, first. 0 0 0 1 1 1 1 00 00 00 0 1 1 0 0 1 1 00 00 10 1 0 1 0 1 0 1 01 11 01 X X X X X X X X X X < - reference mark showing the position of each number

Elements constituting the DNA

The numbers 1, 6, 7, 8 and 15 represent respectively the Hydrogène (H), the Carbone (C), the Azote (NR), the Oxygène (O) and the Phosphore (P). In fact the elements constitute the DNA.

Nucleotides

Désoxyribose C₅OH₇, Adénine C₅H₄N₅, Cytosine C₅H₅N₂O₂, Désoxyribose C₅OH₇

Phosphate PO₄, Phosphate PO₄

Désoxyribose C₅OH₇, Thymine C₅H₅N₃O, Guanine C₅H₄N₅O, Désoxyribose C₅OH₇

Phosphate PO₄, Phosphate PO₄

Double helix

Double helix of the DNA (the vertical bar represents the number of nucleotides)

Humanity

The element in the center represents a Homme. The element on the left intermediate size of a man: 1764 mm. That corresponds to the binary number 14 writing horizontally multiplied by the wavelength of the message (126 mm). The element on the line corresponds to the human population encodée in 32 bits is 4.292.591 583.

Planets

The Solar system: the Sun, Mercury, Venus, the Ground, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto (at the time of the sending of the message, Pluton was regarded as a Planet).

The Earth is shifted to show from which the message comes.

Telescope

The last part represents the radio telescope of Arecibo with its diameter (2430 multiplied by the wavelength what gives 306,18 m).

External bonds

• Banner page of the SETI Institute in connection with the message
• Cornell news: birthday of the message of Arecibo