50 years ago: Arecibo telescope sends message to possible extraterrestrials

Exactly 50 years ago to the day, mankind contacted possible extraterrestrials for the first time with a targeted message. The Arecibo message was sent on November 16, 1974 from the giant telescope of the same name in Purteo Rico in the direction of the globular star cluster Messier 13. This is around 25,000 light years away from Earth, so the message has traveled just two per thousand of the distance so far. Even if the cluster of 300,000 stars will no longer be there when the message arrives, the message could be received somewhere, provided someone has built a similarly large radio antenna.

More and more imitators

Although the Arecibo message was not the first message to be sent into space, none had ever been so systematically developed before. The astrophysicist Frank Drake was responsible for this, who also developed a formula to calculate the number of extraterrestrial civilizations in the Milky Way. Although those responsible took the development of the message seriously, Cornell University later explained that it was actually intended primarily as an advertisement for the performance of a new transmitter installed at the time. Many of the guests present at the event were also impressed.

The message itself consisted of exactly 1679 bits, which had to be arranged in 73 rows of 23 characters each. The SETI Institute explains that the fact that both numbers are prime numbers should help potential recipients to choose this arrangement. At a data rate of 10 bits per second, the transmission therefore took less than three minutes. Correctly arranged, the message results in a pictorial representation of the numbers from 1 to 10, the proton numbers of the elements hydrogen, carbon, nitrogen, oxygen and phosphorus, the chemical components of DNA, the DNA itself, a stick figure, the solar system and the Arecibo telescope itself.

Partly because the intended target was far too distant, the message was not sent with the aim of a comparatively prompt response. Rather, the experiment was intended to stimulate thought and discussion about the difficulties of interstellar communication. This was successful, and messages were subsequently sent into space several times –, including in the form of golden data disks on board the Voyager probes. The iconic Pioneer plaques had already flown into space before. Just last year, an experiment was dedicated to decoding a simulated message from aliens.

Possible successor worked out

Shortly before the anniversary of the Arecibo message, a research team presented plans for a possible successor in 2022. The updated version is again binary coded and explains mathematical and physical concepts in order to establish a universal form of communication. The team has added information on the biochemical composition of life on Earth, a position of the solar system with a date, and a representation of the solar system and land masses on Earth. In their opinion, all this should be sent with a powerful antenna towards the center of the Milky Way, where there is the greatest probability that possible extraterrestrial civilizations will receive the message – in the distant future –.

(mho)