Arecibo Message
The Arecibo Message is a radio message sent into space from the Arecibo radio telescope on November 16, 1974 to commemorate the refurbishment of the radio telescope. The message was 1679 bits long and was sent in the direction of the star cluster (globular cluster) called M13 (object no. 13 in the Messier Catalog of Celestial Objects). This celestial object, located in the direction of the constellation Hercules, at a distance of about 25,000 light years, is made up of about 400,000 stars. The message contains information about the situation of the solar system, our planet and the human being. The message was designed by Frank Drake, Carl Sagan and others.
The number 1679 was chosen because it is the product of two prime numbers and therefore can only be decomposed into 23 rows and 73 columns or 23 columns and 73 rows, so whoever reads it decides to organize the data in the form of quadrilateral. There are eight possible configurations (the eight symmetries of the same pattern) that show a non-random drawing. Of these eight configurations, only the information organized in the second way (23 columns and 73 rows), with the ones and zeros ordered from left to right and from top to bottom, generates coherent information. It is information about the Earth and the human species. In reality, ordering the ones and zeros from right to left and from top to bottom yields the same information. Either configuration contains consistent information.
To decipher the message, you must first identify the ones that are separations of information and the zeros that are the background of the drawing. That is to say: you have to separate the ones and zeros that are part of numbers (in binary) from the ones and zeros that are not part of numbers.
Read from left to right (the image included in this article is reversed with respect to the original message), it presents the numbers one through ten, the atomic numbers of hydrogen, carbon, nitrogen, oxygen and phosphorus (components of the DNA of the Homo sapiens sapiens, the species that sends the message); the formulas of the sugars and bases in the nucleotides of DNA; the number of nucleotides in DNA and its double helical structure; the figure of a human being and the height of it; the population of the Earth; the solar system; and an image of the Arecibo radio telescope with its diameter.
Because the message will take about 25 millennia to reach its destination (and a hypothetical response another 25), the Arecibo message was more a demonstration of human technological achievement than an actual attempt to establish conversation with extraterrestrials.
Explanation
Numbers
The first "line" of the message contains the numbers 1 through 10 written in binary format. It is actually octal (base 8) binary encoded with the most significant digits on the right.
The bottom (4th) row of squares represents the least significant digit, and indicates that the corresponding number starts in the square above and ends three rows above and one column to the right, thus being numbers of six digits. Each number is read from top to bottom and from right to left, with filled squares being 1 and empty squares being 0. The first number, for example, denotes 1 in decimal, written 000001 in binary, and is interpreted like this: 000 in the second column (from top to bottom), 001 in the first (from top to bottom). The last three numbers (decimal digits 8, 9, and 10) also occupy the right-hand column. Thus, the decimal 10 (which in binary is 001010) is interpreted like this: 010 in the second column (from top to bottom), 001 in the second column (from top to bottom); that is, the most significant 1 (on the left) corresponds to the square located in the second column, and the following ones (empty-square-empty) to the first column. The 9 decimal is interpreted like this: 001 in the second column, 001 in the first column. The decimal 8 is interpreted like this: 001 in the second column, 000 in the first column.
DNA Molecules
The numbers 1, 6, 7, 8 and 15 (in binary 0001, 0110, 0111, 1000, 1111), represent hydrogen (H), carbon (C), nitrogen (N), oxygen (O) and phosphorus (P), respectively. These are the components of DNA.
The bottom row of boxes indicates the least significant digit, for each decimal digit.
Nucleotides
- Desoxirribosa C5OH7Adenine C5H4N5, cytosine C5H5N2O2, Desoxirribosa C5OH7 (third line).
- Fosfato PO4, phosphate PO4 (four line).
- Desoxirribosa C5OH7, timina C5H5N3O, guanina C5H4N5O, deoxyribose C5OH7 (quinta line).
- Fosfato PO4, phosphate PO4 (six line).
Double helix
DNA double helix, which is shared by all living things on Earth (the vertical bar represents the number of nucleotides).
(Seventh line).
Humanity
The element in the center represents the human being. The element on the left its average height: 1764 mm.
This corresponds to 14 (written horizontally) multiplied by the only measurement of length that appears in the message, which is neither more nor less than its wavelength (126 mm).
The element on the right represents the size of the human population for 1974 encoded in 32 bits: 4,292,853,750.
(Eighth line).
Planets
The solar system: the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and also Pluto.
The planet the message came from is highlighted out of alignment. The number of points refers to the size of the planet in question.
(Ninth line).
Telescope
The last part represents the Arecibo radio telescope with its diameter (2430 times the wavelength is 306.18 m).
(Tenth line).
Supposed answer
On August 21, 2001, in a wheat field next to the Chilbolton radio telescope, in Hampshire (United Kingdom), a crop circle appeared as a response to the Arecibo message. It is known as the Chilbolton message.
According to ufologists, the message would have been written by aliens. According to others, it would have been produced by anonymous artists, quite possibly by the scientific staff working on the radio telescope.