In November 1962, at a radar station overlooking the Black Sea at the western edge of Crimea, humankind sent its first message to extraterrestrials. It consisted of just three Russian words in Morse code, bounced off of Venus and ultimately headed towards HD 131336, a star almost 2,160 light years away. The first word, Mir, can be variously translated as ‘world’ or ‘peace’. The other words, Lenin, and SSSR, (the Latinised Russian acronym for the Soviet Union), were a little less ambiguous.

Unsurprisingly, we have not heard back from any extraterrestrial intelligence just yet. But since the Morse message, a handful of projects have sent messages beyond the confines of Earth. Some are ambitious attempts to condense human knowledge into a message decipherable by ET. The 1974 Arecibo message, composed by Frank Drake and Carl Sagan, sent graphics of DNA, humans and the solar system to a star cluster 25,000 light years away. In 1972 the Pioneer 10 spacecraft launched, carrying with it a plaque etched with a schematic of hydrogen and the spacecraft’s trajectory around Jupiter and out of the solar system. Five years later, Voyager 1 carried its own interstellar missive, in the form of a golden record carrying images of humans, maps and music by Bach, Mozart, Blind Willie Johnson and Chuck Berry.

Other messages, if they are ever intercepted, may leave ET rather underwhelmed about the prospect of intelligent life elsewhere in the Universe. In 2008, Doritos beamed a 30-second advert towards a solar system in the Ursa Major constellation, just 42 light years away from Earth. Three years earlier, the online classified adverts site Craigslist sent over 100,000 posts into outer space, on the off chance that someone in a far off galaxy was in need of an IKEA Billy bookcase in perfect condition (collection only).

Amongst this hodgepodge of messages, there has never been a sustained, scientific attempt to send a message to aliens. While the search for extraterrestrial intelligence (SETI) has coalesced around a handful of well-funded and significant projects, such as Breakthrough Listen at the Berkeley SETI Research Centre and the China’s FAST telescope, the scientists and amateur astronomers committed to messaging ET have mostly been left to go it alone. But why has the task of composing a message on behalf of the entire human race fallen to the handful researchers who are determined enough to push ahead with the project under their own steam? The problem, it turns out, is that no one can quite agree on the best way to message ET, or even if we should be doing it at all.

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