What kind of messages have we sent to aliens?

 

(Image credit: Haitong Yu via Getty Images)

These messages may simply be a stab in the dark.

In the early 1800s, Austrian astronomer Joseph Johann Von Littrow suggested that humans dig trenches in the Sahara desert in vast geometric patterns, fill them with kerosene, and light them on fire. The goal was to send a clear message to other alien civilizations in the solar system: We are here.

Von Littrow's plan never came to fruition. We haven't given up trying to contact extraterrestrial life long after he suggested his ambitious plan.

So, what kind of messages have we sent to extraterrestrials?

The quest to proclaim Earth's existence became a reality thanks to radio. In 1962, Soviet scientists pointed a radio transmitter at Venus and sent a Morse code salute to the planet. The first of its kind, this introduction contained three words: Mir (Russian for "peace" or "world"), Lenin, and the Soviet Socialist Republic of China (SSSR) (the Latin alphabet acronym for the Cyrillic name of the Soviet Union). According to a 2018 article published in the International Journal ofAstrobiology, the message was mostly symbolic. It was primarily a demonstration of a brand-new planetary radar, a technology that sends radio waves into space with the main goal of observing and mapping objects in the solar system.

The next attempt to reach ET was much more ambitious in terms of distance. In 1974, astronomers Frank Drake and Carl Sagan led a team of scientists from the Arecibo Observatory in Puerto Rico to send a radio message to Messier 13, a cluster of stars about 25,000 light-years away. A human stick figure, a double-helix DNA structure, a model of a carbon atom, and a diagram of a telescope were among the images sent in binary code.

(At his home in Aptos, California, in 2015, Frank Drake, the founder of SETI, sits next to a stained glass window depicting the Arecibo Message. (Photo courtesy of Getty Images/The Washington Post/Contributor.) 

According to Douglas Vakoch, a psychologist and president of Messaging Extraterrestrial Intelligence (METI) International, the Arecibo message attempted to capture who we are as human beings in the language of math and science.

According to the Cornell University Department of Astronomy, it will take around 25,000 light-years to reach Messier 13, at which point the star cluster will have moved. The signal has 10 million times the intensity of radio signals from our sun, so hypothetical aliens may still be able to detect it as it whizzes by. (The sun emits electromagnetic radiation in a wide range of wavelengths, from ultraviolet to radio.) However, astronomer Seth Shostak believes this is impossible.

Shostak stated that it was, in some ways, the most powerful message. It looks like a huge billboard on [US interstate] I-5, but it's in the middle of nowhere.

Radio has more recently been used to broadcast everything from art to advertising. According to an article in the International Journal of Astrobiology, Doritos beamed its own advertisement to a solar system in the Ursa Majoris constellation, about 42 light-years away, in 2008. A message written in Klingon, a fictional alien language from the Star Trek universe, invited real aliens to a Klingon opera in Holland in 2010.

We haven't just relied on radio to communicate; we've also launched spacecraft carrying objects from Earth in the hopes that intelligent life-forms will eventually scoop them out of interstellar space. In 1977, the Voyager 1 and 2 spacecraft were launched to explore the farthest reaches of our solar system and interstellar space. Each one comes with a Golden Record that includes music, Earth sounds, and 116 images of our planet and solar system.

A schematic of the golden record's diagrams (left) (right). (Photo courtesy of NASA/JPL)

The Voyager spacecraft continues to churn through interstellar space, waiting to be detected. But what are the odds of that occurring? Sheri Wells-Jensen, an extraterrestrial intelligence linguist, said, "Zero."

Wells-Jensen described it as "just a beautiful and poetic, charming, courageous attempt that really did sum up kind of the best of us," even if it was "pointless in terms of actually communicating."

Experts agree that there is a slim chance that any of these efforts will succeed in reaching alien civilizations. Of course, whether or not there is alien life in our star system determines the outcome. However, the life in question would have to be alert for radio signals and have a basic understanding of math and science in order to decipher our messages. Finally, our messages presume that these aliens perceive the universe in the same way that we do: through hearing and vision.

That isn't to say that all of these messages are ineffective. We're on the lookout. What makes you think they aren't looking? Wells-Jensen briefed about his findings. What if these hypothetical creatures are unable to understand our messages? That's fine. Wells-Jensen stated, I think the most important thing we've ever said is just that we exist.

Originally published on Live Science.