Anybody Out There? History of Space Messaging

It’s nighttime. You’re about to go to bed but you notice an odd shadow crawling into your garden’s bushes. Would you rather call out to it “Hi, what can I do for you?” or get your phone and dial 911? Or at least, remain silent while you figure out what it is? I guess we’d both go for the safe option, ranging from the silent observer state to the runaway kid.

Nonetheless, regardless of our sharp surviving skills, it seems like the “don’t talk to strangers” yes-Mum-I-know-rule did not quite made its way to the brain of all human beings. Surprisingly, the world’s smartest minds have been first in line to break the rule, sending messages to the faraway corners of the galaxy for years.


Search for Extra-Terrestrial Intelligence (or SETI) has been undergoing for nearly half a century. As soon as humans could master a technology that was able to send messages across the universe – the Beatles’ eponymous song was also broadcasted towards the North Star in 2008 – they decided to start a game of hide and seek among the galaxies, and sent random invitations to join.

One of the first messages of this (third) kind was the Arecibo message, named after a Puerto Rico telescope with a 300-meter long antenna. In 1974, it was used to broadcast a simple, binary-encoded message towards the Hercules Globular Cluster – some 22,000 light-years away. The message contained some information about our civilization: numbers from 1 to 10, DNA components, basic shape of a man, average population, our position within the Solar System (yes, they know) and other bits of information that amount to 1,679 bits in total.

A colored version of the Arecibo Message: looks like early messaging-to-space tries were the responsibility of a kid who had just discovered Paint. (Source: Arne Nordmann via Wikipedia, CC BY-SA 3.0)

Three years later, as the Voyager Golden Record was about to launch, astronomer Jerry Ehman was working on data provided by the ‘Big Ear’ radio telescope (Columbus, Ohio) when, at 22:16, he noticed an anomaly in the signal intensity, about 30 times higher than normal levels. He immediately circled the numbers involved and added ‘Wow!’ next to it, which would later cause it to be called the ‘Wow! signal’. Originating from the Sagittarius constellation, it was interpreted by some as an attempt for aliens to communicate with us. However, no scientific evidence was brought to support this case (or no evidence was made public… that’s your call, conspirators). Other assumptions involved complicated terms as ‘interstellar scintillation’ or ‘cosmic clouds’ but the origin of the signal, never to be heard again, remains a mystery to this day.

The Wow! signal reads “6EQUJ5”. Can you break that code? (Credit: Big Ear Radio Observatory and NAAPO via Wikipedia)

Other similar experiments include the Golden Record aboard Voyager I and II (1977), the Cosmic Calls (1999 and 2003), the Lone Signal (2013)… Human beings have figured out pretty creative ways to send information to alien civilizations, ranging from the “that’s a picture of us, look” – Pioneer spacecraft, 1972/73 – to the digital time capsule – A Message from Earth, 2008. The latest was sent towards the planet Gliese 581c, located about 200 trillion-kilometers away, apparently because this planet could likely display Earth-like conditions. (So far the capsule has achieved about a third of the total journey.) And it raised a concern among the scientific community: what if our efforts to messaging extraterrestrial life did not turn out the “cool, let’s make new friends!” way?

A paper published in 2015 followed this interrogation: its conclusion was that “intentionally signaling other civilizations in the Milky Way Galaxy raises concerns from all the people of Earth, about both the message and the consequences of contact. A worldwide scientific, political and humanitarian discussion must occur before any message is sent.” Sounds serious, right?


Over the past century, we’ve been sending lots of stuff into space: shuttles, satellites, probes, rockets, monkeys, dead people’s ashes, many sounds from Earth, a pizza (Pizza Hut becoming in 2001 the first interstellar pizza delivery company in the world), along with brave men and women and a lot of messages. So the basic idea was: humans don’t know if there’s life anywhere outside their home planet; so why not sending a message as far as their technological capabilities enable them see if it gets a reply? That could have sounded cool back in the 80’s when E.T. was a hit, but right now, the overall scientific community is less than enthusiastic about communication with potential alien life sources. As Stephen Hawking puts it, “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”

Plus, even though extraterrestrial life forms would not turn out that bad, how would they reach out to us? They probably wouldn’t understand binary, and will make no sense of the sound of a wave or a baby picture – could they even count, listen, or see? What if aliens don’t have concepts for colors, numbers, life, death, love? Finally, assuming they exist – after all, Carl Sagan’s take on the Drake equation estimated that about a million intelligent civilizations could live in the Milky Way – what if they communicate with us through the pattern of the clouds or the frequency at which dogs wag their tails, and we still haven’t noticed?


Humans’ supremacy on Earth was sealed when their intelligence enabled them to dominate their environment. Hence they cut off trees, drilled the oceans to fuel their machines, paved roads, opened supermarkets and powered nuclear stations, with little respect to the surrounding atmosphere and biosphere. Hence the big question mark hanging over our home planet: if we don’t mind stepping on a bug, why would a faraway civilization treat mankind any differently?



Author: Nicolas

Ingrédients : 33% d'anecdotes insolites, 19% de livres poussiéreux, le reste de curiosité névrosée. Auteur du Petit dictionnaire des sales boulots (Vendémiaire, 2022). Chroniqueur chez Slate et RetroNews.

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