On Nov. 16th, 1974, the most powerful signal ever beamed into space was broadcast from the Arecibo Radio Telescope in Peurto Rico. Designed by famed SETI researcher Frank Drake (creator of the Drake Equation) and famed science communicator Carl Sagan, the broadcast was intended to demonstrate humanity’s level of technological achievement. Forty-eight years later, the Arecibo Message remains the most well-known attempt to Message Extraterrestrial Intelligence (METI).
To mark the occasion, an international team made of researchers led by Jonathan H. Jiang of NASA’s Jet Propulsion Laboratory has come up with a new signal! Known as The Beacon in the Galaxy (BITG) message, this updated signal combines aspects of the original Arecibo Message with every METI attempt made to date – like the Pioneer Plaques, the Voyager Golden Records, and the Evpatoria Transmission Messages (ETMs).
Jiang was joined by researchers from the SETI Institute, the Virginia Polytechnic Institute and State University, the University of Cambridge, the Hanze University of Applied Sciences, the Chevron Energy Technology Company, the School of Physics and Technology at Wuhan University, Beijing Normal University, and the University of California at Los Angeles. The paper that describes their findings recently appeared online.
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The Original Signal
The transmission was part of a ceremony that marked the end of a three-year upgrade to the Arecibo’s 305m (1000 ft) Radio Telescope. This included aluminum panels on the giant spherical reflector antenna to improve accuracy, a high-power S-band radar transmitter, and modifications to the superstructure to accommodate S-band frequencies. The emission was equivalent to a 20 trillion watt broadcast and would be detectable about anywhere in the galaxy if the receiving antenna was similar in size to Arecibo’s.
The message’s destination was M13, a globular star cluster located near the edge of the Milky Way Galaxy (about 22,180 light-years away). This cluster was believed to be a good candidate for finding intelligent civilizations since it is estimated to be 11.66 billion years old and contains approximately three-hundred thousand stars. Drake and Sagan decided to use prime numbers since they believed it would make the message easier for an alien civilization to translate.
“The Arecibo Message was the first carefully designed message into space, encoded in radio waves, hoping to get in touch with alien civilizations,” said Jiang to Universe Today via email. “It pioneered Earth’s first attempt to contact aliens.
The broadcast consisted of a 1,679-binary digit pictogram (210 bytes), which is the product of two prime numbers, arranged rectangularly into 73 lines of 23 characters per line (also prime numbers). The ones and zeroes were simulated by shifting the frequency at a rate of 10 bits per second, and the total broadcast lasted less than three minutes. 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 ab 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)
Before and Since
Numerous METI attempts have been made since the beginning of the Space Age. The first radio signal deliberately broadcast to space was the Morse Message, which was sent from the Evpatoria Planetary Radar (EPR) in Ukraine in 1962. This broadcast sent a series of brief radio messages to Venus consisting of three words encoded in Morse code: “Mir” (“Peace” or “World” in Russian), “Lenin,” and “USSR.”
Between 1999 to 2016, several more messages were attempted that targeted stars between 17 and 69 light-years from the Earth. In the coming years, Breakthrough Message plans to mount an international competition (with a prize purse of $1,000,000 for winning entries) to create messages broadcast by their participating institutes. As Philip E. Rosen, a retired energy industry engineer and a co-author on the paper, said:
“Following the 1974 Arecibo Message there were two transmissions made from the Evpatoria 70-meter dish located in the Crimea, Ukraine, these occurring in 1999 and 2003. The Evpatoria transmissions were overseen by a pair of Canadian researchers, Dr. Yvan Dutil and Stéphane Dumas, and were beamed at a total of nine relatively nearby stars ranging in distance from Earth of 10.1 to 21.6 parsec. The 2003 transmission utilized a more robust (i.e., distortion/error resistant) version of the message sent in 1999.”
Other messaging attempts include the Pioneer Plaques that adorned the Pioneer 10 and 11 spacecraft, the first robotic missions dispatched to the outer Solar System. These messages were the brainchild of Carl Sagan and constituted the first “message in a bottle” sent by humans to space. They depict the location of Earth in the Galaxy, two circles representing neutral hydrogen, and a naked man and woman drawn in relation to the spacecraft.
This was followed by the Voyager Golden Records, also crafted by Carl Sagan and his colleagues at Cornell University, which were meant as more of a “time capsule.” The cover depicted instructions on how to play the record, which contained sounds and images that portray life and culture on Earth. Also depicted are the same pulsar maps and representation of neutral hydrogen featured on the Pioneer Plaques.
Enter the BITG
The BITG message comprises 13 parts that consist of approximately 204,000 effective binary digits, or 25,500 bytes, overall. Based on the optimal timing during a given calendar year, the team determined that the Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China and the SETI Institute’s Allen Telescope Array in northern California would be well-positioned to send the Beacon.
As for the target of the broadcast, Jiang and his colleagues chose a concentric ring that is 4 kiloparsecs (~13,000 light-years) from the galactic center. In a previous study, Jiang and other co-authors determined that the center of the galaxy is the most likely place for intelligent life to have emerged. This is bolstered by similar research demonstrating how the galactic center is the best place to search for technosignatures.
“Therefore, we choose stars between 2 kpcs and 6 kpcs from the galaxy’s center as the intended destination. We maximize the chances of the message being received by an ETI and maximize the probability of receiving a response in the distant future,” said Jiang.
The message was designed and coded by co-authors Matthew Chong (the University of Cambridge), Hanjie Li (Virginia Polytechnic Institute and State University), and Qitian Jin (Hanze University of Applied Sciences). As they explained, the Beacon Message incorporates elements from all METI attempts to date.
“The main part of the beacon in the Galaxy (BITG) Message contains a new combination of graphical information in the form of images and special “alphabets” to represent numbers, elements, DNA, land, ocean, human, etc., similar to the 1999/2003 Cosmic Call by Stephane Dumas and Yvan Dutil,” said Jiang. As Li added, the Beacon relies on the same mathematical language as Arecibo:
“The BITG message starts and ends with a prime number set (2, 3, 5, 7, 11…) to let itself stand out from the EM waves that can be easily picked up by extraterrestrial intelligent (ETI) civilizations. A new mechanism in message design may help ETI to decode our message: the Row Length Indicator (RLI), which is a repetition of a designated number of zeros and ones. The original Arecibo message is a rectangular block with the same number of elements per row. With RLI, the message can be made of several matrices of zeros and ones in different sizes that enable more flexibility to the content design and decode by ETIs.”
“The BITG message also contains a Location Stamp and a Time Stamp,” said Jin. “The Location Stamp describes the Solar System’s position in the galaxy by using globular clusters as landmarks. The Time Stamp uses Hydrogen Spin-Flip to estimate the time we create/send the message in respect to the theoretical birth of the universe.”
To Listen or to Message?
The publication of the Beacon message comes at a particularly auspicious time. Thanks to renewed interest in space exploration, there has been a growing movement to revitalize the Search for Extraterrestrial Intelligence (SETI). As a result, there is a growing debate between advocates for “Passive-SETI” (listening) and “Active-SETI” (messaging). Whereas some feel that METI is “more global and unselfish” in focus than conventional SETI (Zaitsev, 2006), others feel it’s unnecessarily risky.
However, Jiang and his colleagues emphasize that no formalized discussion has been made regarding the risks or ethics of broadcasting. In the meantime, Jiang points out that humanity is already transmitting (albeit unintentionally):
“[W]e are aware that there have been calls for discussions on whether it’s safe to broadcast this type of message. It is always worth pointing out that we humans are unintentionally sending out signals about our presence, albeit at a much lower intensity, which signals have not been designed to put us in the best light (e.g. the ongoing war). They likely would have managed their contact better if there had been intentional communication sent out.”
In the end, the team believes that the ongoing development of the Beacon message may help ensure that this conversation takes place. Another benefit of their work is that it is being done in the open, something that is essential to any METI effort. Said Jiang:
“[This] is important because there are concerns that some power could initiate a broadcast without being open to the rest of the world. This is another reason to promote broadcasts with open participation, to avoid there being only secret broadcasts. This is why our BITG message is being finalized and published openly, inviting feedback from all interested parties.”
“The BITG message should be promoted as a means of inspiring our human civilization to be better at living sustainably,” adds Stuart Taylor, a nuclear physicist with the SETI Institute. “We must consider human survival as a goal more than we do, rather than caring too much about our own separate nations.”
The Arecibo Message was broadcast at the height of the first Space Age and showcased what humanity’s facilities were capable of. For many people worldwide, the loss of the Arecibo Observatory in 2020 felt like the end of an era. As we enter a renewed era of space exploration and astronomy, updating and adding to what was undoubtedly one of our “greatest hits” seems appropriate!
Further Reading: arXiv