The Last Arecibo Message Celebrates the Observatory and One of its Greatest Accomplishments

The Arecibo Message, transmitted on November 16th, 1974, from the Arecibo Observatory, was humanity’s first true attempt at Messaging Extraterrestrial Intelligence (METI). The message was a simple pictorial signal in binary code composed by famed astronomer and SETI researcher Frank Drake (inventor of the Drake Equation) with the assistance of Sagan and other prominent astronomers. The message was and was aimed toward Messier 13 (NGC 6205 or “The Great Hercules Cluster”), a globular star cluster located about 25,000 light-years from Earth in the constellation of Hercules.

In 2018, in preparation for the 45th anniversary of the historic broadcast, the Arecibo Message Global Challenge was launched. Student teams were tasked with designing a new message that could be sent to space, and by August 2020, the Boriken Voyagers team was recognized as the winner of the competition. Unfortunately, the Observatory collapsed on December 1st, 2020, and the message was never sent. To commemorate the 50th anniversary of the Arecibo Message, the Boriken Voyagers have shared “The Last Arecibo Message.”

The Boriken Voyagers team consists of eight students from the University of Arecibo Mayagüez Campus (RUM) and the Planetary Habitability Laboratory (PHL) at the University of Puerto Rico at Arecibo. Boriken is the name for Puerto Rico in the language of the Indigenous Taino/Arawakan people. The group is led by Kelby D. Palencia-Torres, a student at RUM and PHL who specializes in the study of the gas and dust surrounding galactic disks – aka. the Circumgalactic Medium.

The Original Message

The Arecibo Message was organized by Drake in the early 1970s as the first campaign to compose a message destined for space. The effort relied on Arecibo’s megawatt transmitter attached to its 305-meter (1000-foot) antenna to send a 20-gigawatt omnidirectional broadcast. The M13 cluster was selected because of the number of stars (about 300,000) and the cluster’s age (11.65 billion years). This made it seem a likely place to host an extraterrestrial civilization. The message was not intended as an invitation to talk nearly as much as a demonstration of human technological capabilities and scientific knowledge.

The message was transmitted on November 16th, 1974, at a frequency of 2380 MHz and an effective bandwidth of 10 Hz. The message was transmitted at a frequency-shifting rate of 10 bits per second and lasted less than three minutes. It consisted of a 1679-binary digit picture (210 bytes) – the product of two prime numbers – arranged rectangularly into 73 lines of 23 characters per line (also prime numbers). The use of prime numbers was deliberate since mathematics is considered the only “universal language” and easier for an alien civilization to decode.

They conveyed a series of scientific, geographical, biological, and astronomical information in different colors. These included:

• A counting scheme of 1 to 10 (white)
• The atomic numbers for hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up DNA (purple)
• The chemical formula of the four purines and pyrimidine bases that make up DNA (green)
• An image of the DNA double helix and an estimate of the number of nucleotides (blue and white, respectively)
• A stick figure of a human being (red), our average dimensions (blue/white), and the human population of Earth (white)
• A depiction of the Solar System, indicating that the message is coming from the third planet (yellow)
• A schematic of the Arecibo Observatory and its dimensions (purple/white and blue)

Fifty years after the Arecibo Message was sent, its legacy lives on. Universe Today recently caught up with the Boriken Voyagers to learn more about the original message and their updated version. The team members included Kelby D. Palencia-Torres, Cesar F. Quinones-Martinez, Javier A. Garcia Sepulveda, Luis R. Rivera Gabriel, Lizmarie Mateo Roubert, German Vazquez Perez, and Abel Mendez.

Q: Why does the Arecibo Message endure 50 years later?

Germán Vázquez Pérez: “Even 50 years later, and despite the loss of the Arecibo Observatory, the Arecibo Message continues its journey through the vastness of space, waiting to be intercepted by potential civilizations. It’s a bittersweet feeling. The message remains an example of what humanity can achieve, but we no longer possess the same capability to receive a potential reply or transmit another message with such power and significance. At least for the moment.”

Kelby Palencia-Torres: “The significance of the Message is that it represents humanity, and it is the first intentional message of our existence in the cosmos. The message compels curiosity, and it’s our first step to answering the old question if we are alone in the universe.”

Lizmarie Mateo Roubert: “The Arecibo Message can represent the hope people working in the scientific community have in answering questions about the Universe and all the efforts they have put in throughout the years.”

Cesar Quinones-Martinez: “The Arecibo Message has fascinated many throughout the decades, bringing a lot of debate as to whether or not we should actively contact other extraterrestrial civilizations. Arecibo and the Arecibo Message for Puerto Rico represent a collective curiosity in space exploration, as for many students on the island, visiting Arecibo becomes a key motivator to beginning their STEAM journey. It represents a bold step into the unknown, where our curiosity takes us to make new discoveries. “

Q: How has the field of SETI/METI changed since?

Cesar Quinones-Martinez: “The SETI and METI initiatives both have seen improvements to their capabilities as technology improves. Bigger, more sensitive detectors bring us closer to receiving any artificial signal, while better transmitters could allow for future messages that can better retain their information while passing through gas clouds or other mediums. While the Arecibo Message was designed to showcase Arecibo’s capabilities, current METI projects are more rigorous with what they want to communicate. We do not know the intentions of the recipient of our message, and measures must be taken to be direct with what we say.”

Kelby Palencia-Torres: “With METI, we are more cautious with the content included in the messages. Some sci-fi series like the ‘3 Body Problem’ play a negative role in how METI is perceived outside the scientific community.”

Q: What was it like to compete in the Arecibo Message Global Challenge?

Kelby Palencia-Torres: “The New Arecibo Message Global Challenge was an intriguing and daring competition. To partake and enlist in the challenge, one had to solve a riddle. After this first stage of the challenge, we had to solve a puzzle where the situation was similar to that of the movie Contact. We had to decode a message and identify the location of said message. Once proven to solve the puzzle, we passed to the last stage, where we had to develop the New Arecibo Message. As part of the challenge of the message, we had to consider the energy used to produce the signal and transmit it, choose a location visible to the Arecibo Telescope, and the hardest part … fully create the content of the message itself.”

Lizmarie Mateo Roubert: “At the time, this was truly the most difficult part of the challenge we had encountered so far. Back in 2018, most of us were just beginning our undergraduate degrees and some of the information we needed to keep in mind whenever we were to develop a message in a way that could be encoded eventually proved to be a bit of a struggle. With the help of other professionals in the field and professors on our university campus, we were then able to fully understand how to properly develop this message and the different conditions and capabilities we had to keep in mind so the message could be successfully sent and deciphered.”

Luis Rivera: ‘It proved to be a space for great professional and personal growth for me. The difficulty behind solving the problems and creating something new that t underscored the need for teamwork in all aspects of science, and helped me grow closer to people I call my friends today.’ 

Cesar Quinones-Martinez: ‘The Arecibo global Competition consisted of 3 stages to highlight important stages of making the message: interpretation, decoding a received message, and finally writing our New Arecibo Message. The first stage showed how clever message design can contain a lot of information about the subject material. Imagine a pixelated image of a human sent at a certain frequency. How do you figure out the human’s average height? The key is the frequency, which corresponds to a specific wavelength so that by counting the pixels, you can approximately obtain the height.

“However, is that all the information you can extract from the image? Knowing the size of the pixels, you can figure out the ratio of the head to the arms, legs, and abdomen, communicating more about humans without added complexity. The second stage gave us a scenario with a received message that we needed to decode. The team regularly pitched different ideas on what aspects of the signal were important to decode, which was useful to the design of the new Arecibo Message in the final stage. The competition was a great exercise in thinking outside the box and looking at different perspectives, showing the nuance of communicating efficiently when the turnaround time can be centuries.’

The Last Arecibo Message

Lizmarie Mateo Roubert: “The content of the Last Arecibo Message contains information about humanity’s knowledge of mathematics, science, and astronomy. The first two sections include the numbers from 1 to 10 and the arithmetic symbols including the equal sign. We included mathematical and physical constants such as pi, the Euler constant, the speed of light, the Planck constant, and the Stefan-Boltzmann constant. Adding these constants in our message helps us with a variety of assumptions regarding the recipient’s understanding of the universe..” 

Germán Vázquez: “We also wanted to share astronomical aspects of our galaxy, solar system, and earth-moon system to pinpoint our location in the universe. The image of the Milky Way Galaxy is presented (up to scale) with the distance from the Galactic center to our solar system.

“The Arecibo Message, sent in 1974, served as a direct inspiration for the next section of our message, our Solar System. However, we wanted to enhance some aspects to make it more descriptive and accurate. We included our Moon and Saturn’s rings, enhanced the sizes of the gas giants, and excluded Pluto, which is now considered a dwarf planet.

“The Earth-Moon system was also implemented in our message, considering the impact our natural satellite has had in shaping humanity, influencing our calendars, producing ocean tides, and understanding celestial mechanics. Lastly, our depiction of a human being, the average height, and the population in 2020 were also included, alluding to the original message.”

Kelby Palencia-Torres: “The purpose of the message is to continue the legacy of the Arecibo Observatory and the Original message by Frank Drake. Our message sums up humanity’s curiosity and wanting to explore the universe together.”

Q: “What significance could this have for the ongoing debate concerning METI?“

Kelby Palencia-Torres: “The message we constructed for the Arecibo Message Global Challenge was to commemorate and demonstrate the importance the original had. Currently, our message does not have plans to be transmitted. But it showcases the innate curiosity and feelings we have to see if we are alone. Our message will go to the list of messages built with METI purposes and show the interest in taking the first step in communicating with other intelligence.

“One of the assumptions we use in our paper can also back up METI since other civilizations with similar capabilities to our civilization will face the same constraints as SETI. Whoever listens will need resources, energy, and telescope time to look for techno signatures in their sky. Assuming that other civilizations have a greater technological feat than us, it would mean giving access to resources and a really big and sensitive radio telescope to a being from this advanced civilization to search for techno signatures, and it all would be reduced to be lucky enough to be looking at the right moment and time to receive a one time signal that is not continuous such like the original Arecibo message or the wow signal.”

Further Reading: arXiv