The Arecibo message: Humanity's first broadcast to the stars

Key topics:Humanity’s first deliberate radio message sent to space in 1974Details of the Arecibo Observatory’s powerful transmitter and designDebate over risks and ethics of contacting extraterrestrial life.Sign up for your early morning brew of the BizNews Insider to keep you up to speed with the content that matters. The newsletter will land in your inbox at 5:30am weekdays. Register here.Support South Africa's bastion of independent journalism, offering balanced insights on investments, business, and the political economy, by joining BizNews Premium. Register here.If you prefer WhatsApp for updates, sign up to the BizNews channel here..By Toni Botes.Until 1974, humanity had unintentionally transmitted high-frequency radio, TV, and radar into space, reaching thousands of nearby stars. But astronomers wanted to go further and send a message into the depths of the Milky Way. They wanted to send a message that had the potential to reach other intelligent lifeforms and communicate something more about our civilisation. So, in 1974 astronomers broadcast a message to the universe from a newly installed transmitter at the Arecibo Observatory in Puerto Rico. It wasn’t only a show of the observatory’s technological prowess but also an attempt to tackle the difficulties of communication across time, space, and cultures. Today, our list of questions continues to grow. The technology behind the Arecibo ObservatoryThe Arecibo Observatory was home toa megawatt transmitter attached to a 305-metre antenna. From this monument to our technological advancement, a coded message was broadcast on the 16th of November, 1974. Using a method similar to that of an old computer modem sending binary code over a landline, the message was broadcast for just under three minutes. Comprising 1 679 binary bits, the message was transmitted at a frequency of 2 380 MHz. The binary ones and zeros were communicated by shifting the signal’s frequency up and down over a range of roughly 10 Hz. Once decoded, the message would form an image 23 characters wide and 73 long.The 20-gigawatt omnidirectional broadcast was directed towards a group of about 300 000 stars called the Great Cluster in Hercules, Messier 13. Though still in the Milky Way, this cluster of stars is 25 000 lightyears away. The Arecibo message was directed at this cluster because its age (11.65 billion years) and the number of stars increased the likelihood of the presence of intelligent life. That said, they would need to be more than intelligent; at the very least, they would need access to technology similar to that housed in the Arecibo Observatory just to detect the message.Unfortunately, due to the mechanical stress placed on the Arecibo Observatory by natural disasters such as Hurricane Maria in 2017 and earthquakes in early 2020, the structure collapsed in December 2020..The contents of the Arecibo message.Now, if this whole situation wasn’t complex enough, there’s also the matter of the message itself. Frank Drake not only spearheaded the research and development of the technology required to send the message, but was also instrumental in developing the message itself. In collaboration with a large team of astronomers, notably Carl Sagan, they devised what they saw as the perfect message. The aim of the message was to communicate a series of scientific, geographical, biological, and astronomical information about us rather than to elicit a response.The information contained in the Arecibo message as read from top to bottom is as follows:White - our counting scheme from one to tenPurple- the atomic numbers for the elements which make up our DNA (hydrogen, carbon, nitrogen, oxygen, and phosphorus)Green- the chemical formula of the four purines and pyrimidine bases that make up DNABlue and white – the double helix structure of our DNA and an estimate of the number of nucleotides contained thereinRed – a simplified human formBlue and white – the average dimensions of a humanWhite – earth’s population at the timeYellow – a rough depiction of our solar system emphasising the third planet; earthPurple, blue and white – a simplified image of the Arecibo Observatory and its dimensions.Asking the real questions.Having covered the technical minutia, it’s time to ask the real questions. For all their intellect, ability to develop the technology required, and the creation of a concise message, one must ask whether sending this message was a smart move. It’s a controversial concept best illustrated by the genius of Steven Spielberg in 8k CGI and Dolby True HD – maybe you should mind your business. Thus far, the safest way to explore the universe has been passively, by listening; this method is referred to as SETI (searching for extra-terrestrial intelligence). METI (messaging to extra-terrestrial intelligence), as done through the Arecibo message, is the polar opposite which opens a Pandora’s box of infinite possibilities.Varying perspectives have invited debate, with the likes of Stephen Hawking weighing in on the topic. Announcing our existence to potential alien civilisations poses an existential risk to humanity. While some have taken it upon themselves to continue METI efforts, the SETI community has taken a hard line against it. In 2015 the SETI community went so far as to issue a statement acknowledging the potential risks, suggesting it better to open an international debate on the matter before furthering METI efforts..How could the Arecibo message be used?.Naturally, our imaginations run wild. What an advanced civilisation could do with the information contained in the Arecibo message is infinite. More than popping in for a cup of tea, they could replicate our DNA and create an army of indentured servants to do their bidding. Comforting. Alternatively, they could just send us greeting cards every festive season. Who’s to say? These days at least we have social media to teach us the pitfalls of sending our most intimate information to complete strangers.The thing is, perhaps Stephen Hawking and his cohorts were a little alarmist. Here are the facts: at 25 000 lightyears away, the message would take at least 25 000 years to reach M13. Furthermore, the core of the M13 will no longer be in the same location - owing to the orbit of the star cluster around the galactic centre. Instead, the message will arrive nearer to the centre of the cluster. So, for now, the future is bright.

The Arecibo message: Humanity's first broadcast to the stars

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