• Fraser du Toit

The Arecibo Message - Calling All Aliens

Meeting another intelligent species living in our universe would be a great moment in human history. Whether our galactic brethren meant us harm or had peaceful intentions, the human race would never be the same again. Some scientists believe that broadcasting our presence into the cold void of space is a bad idea. They believe that any civilization advanced enough to receive the message, and travel to greet us, would be so advanced that, should they be aggressive, our extinction would be guaranteed.

Those scientists were understandably miffed when in 1974 a team led by Dr Frank Drake blasted a coded message into space from the Arecibo Observatory in Puerto Rico. This was done as a part of the SETI (Search for Extra Terrestrial Intelligence) initiative.

Who is Frank Drake?

Frank Drake was born in 1930 in the United States of America. He joined the US Navy after graduating from high school, and studied Astronomy at Cornell University through the Navy Officer's program. Once he obtained his degree in Astronomy, he served a short stint on the USS Albany as an electronics officer.

Drake became fascinated with the idea of searching for alien life after attending a lecture by Otto Struve. At the time, it was commonly believed that most stars existed in solitude, without accompanying planets. Struve however, had observed that most stars spin much more slowly than they theoretically should. His conclusion was that most stars are in fact surrounded by planets. This holds the implication that life might also exist on those planets, as it does here on Earth.

Drake's imagination was ignited by the idea of alien life existing somewhere in what had previously seemed an empty expanse. He would dedicate much of his life to trying to find it.

Frank Drake is perhaps most famous for coming up with what is known as the Drake Equation. This equation was a thought experiment to try to work out the number of active intelligent extraterrestrial civilizations in the Milky Way galaxy.

Dr Drake got the idea in 1961 while attending a SETI conference. He took a look at all the prominent speakers who were attending the event, and it sparked an idea. All the topics that were to be discussed could fit into a simple equation. Thus, the Drake Equation was born, and it has since become the standard for speculation about the number of intelligent alien species rattling around the cosmos.

SETI - Looking For Aliens

There have been many experiments over the years to try and find extraterrestrial intelligence. Going back as far as 1896, Nikola Tesla suggested that his wireless electrical transmission technology could be used to contact beings on Mars. Tesla also famously believed that his inventions were beamed into his brain by beings from beyond the Earth.

All of these experiments fall under the banner of SETI, despite the institute not being formalized until much later. Many of the most significant steps were taken long before the idea was incorporated.

The first modern SETI experiment was conducted by Frank Drake himself in 1960. He used a radio telescope to scan the stars in the Tau Ceti cluster, but found nothing of interest.

The Search for Extra Terrestrial Intelligences (SETI) Institute started as a NASA project with only two researchers involved, Tom Pierson and the astronomer Jill Tarter. Founded in 1984, and officially going to work in 1985, SETI was founded to investigate the components of the Drake Equation.

Frank Drake was one of the founding Trustees of SETI. The Institute has grown since its inception to now include over 100 participants. Other famous scientists like Carl Sagan and Baruch Blumberg have served on the Board of Trustees.

The Arecibo Message - Ill Advised, or Genius?

In about 25,000 years, the potential inhabitants of the Great Hercules Cluster will be receiving a coded message from Earth. This message was blasted into space from the Arecibo Observatory in Puerto Rico by a team of scientists led by Frank Drake. Not everyone in the scientific world agreed that the message should be sent, but Drake's team threw caution to the wind and did it anyway.

Frank Drake's team included the famous astronomer Carl Sagan, among other scientists. They carefully crafted a message to announce humanity's presence to the stars. This message was made up of a binary code that can be translated into a picture.

The message contains the following information:

  • Our counting system (1-10)

  • The Atomic Numbers of the elements that make up our DNA (Hydrogen, Nitrogen, Carbon, Phosphorus, and Oxygen)

  • The chemical formula for the nucleotides that forms our DNA

  • An image of our double helix DNA (in blue) and an estimated number of nucleotides that make up our DNA (in white)

  • The human figure (in red) that shows the basic composition and layout of our bodies

  • Our average measurements

  • The total population at the time that the message was sent

  • Our solar system is depicted in yellow, with the third planet being elevated to indicate that that is where we are from

  • Finally, we have the Arecibo Observatory itself (in purple) along with its dimensions in white and blue.

This message was blasted into space as a 20-gigawatt omnidirectional broadcast from the Arecibo Observatory's 305-meter antenna. Any intelligence on a planet with a similarly sized antenna can pick up the message. Whether they would be able to decode it is another matter entirely.

While many researchers were against the message, it was done more as a display of technical ability than a legitimate attempt at starting a dialogue with alien intelligences.

The Unexpected, Unwanted, Arecibo Reply

One cloudy day in August 2001 in Hampshire, UK, two crop circles appeared near the Chilbolton Radio Telescope. These enigmatic crop circles appeared overnight in a field that would have been well monitored. What makes these crop circles more mysterious is that they appear to be a direct response to the Arecibo Message.

The Arecibo Answer was printed in flattened crops and took the same form as the original message.

At first glance, the message appears to be similar, but certain key elements have been changed. For example, the base compound of the chemical makeup here is silicon instead of carbon. The DNA is shown to be different as well, having a whole extra helix added. They also indicate that they inhabit the third, fourth and fifth planets in their home system.

Most notably, we have the figure that replaces the stick figure human from the original message. Here we see the small body, large head, and big eyes of the most common type of Alien claimed to be encountered on Earth, the Short Grey. Some people will claim that the Grey alien is an invention of pop culture, and while it is popular, that isn't true.

The original description comes from the Betty and Barney Hill abduction case.

Many people dismissed the message outright. They believe firmly that all crop circle phenomena can be explained away by people sneaking around in the fields at night. While there are known hoaxers out there, some phenomena associated with crop circles are a bit harder to explain away. Those include electromagnetic interference recorded in the circles, abnormal levels of radiation being present, and the stems of the crops being deformed in a way inconsistent with being flattened by wooden planks.

The reply was joined a few days later by another crop circle. This one shows a Grey alien's face with some artistic shading. The whole thing appears to be intentionally ominous.


It appears that the enigma surrounding the Arecibo Reply was quickly solved as a hoax. Logically, it makes little sense for aliens to pick up a radio transmission from several light-years away, and then to travel to Earth to play Tetris with some crops instead of a more direct message.

The Arecibo Message is doomed to miss its intended target anyway, as by the time it traverses the 25,000 light-years to reach the Great Hercules Cluster, those stars will have moved.

Human attempts at communication with the stars continue, though, and eventually we are bound to find someone out there. That is, unless all the other aliens are dead, and we are alone, as per the Fermi Paradox.