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SETI – Searching for Life

Are we alone? 

It is a question that has enthralled and perplexed us ever since we became aware of the extent of the universe. A question that has led us to spend millions of hours combing through data brought back from the far reaches of the universe in the search for that elusive sign – that no, humans are not alone. 

The Search for Extraterrestrial Life (SETI) is a term used for the collective search that is being done around our world – and beyond. The aim, as if that wasn’t exceedingly obvious, is to find other life forms in the universe. This is done through the monitoring of radio waves, electromagnetic radiation and much more, as well as beaming out our own messages in the hope that one day we might get a response.  

Whether extraterrestrial life exists or not is a keenly debated question and one that tends to draw the extremes of both sides. Some believe vehemently that there is life out there and that we have already been visited by such beings. Roswell, Area 51 – little green men, and of course anal probes – the myth around our alien visitors is both tantalising, and yet to be proven. But to many, it’s simply not a question of ‘if’ there are extraterrestrial beings – but where. 

On the other side, some find the notion of extraterrestrial life absolutely absurd. It is placed in the same box as ghosts, vampires and werewolves – fun stories, but without any hope of being true. 

As I said, these are the extremes. Most sit somewhere in the middle, open to both possibilities, but aware that absolute proof is needed. We are after all not talking about man-made mythical stories – SETI is led by science, and it’s only through such science that we will ever be able to answer the question of whether we are alone in the universe.

Our Universe  

Scientists estimate that the number of potential planets in our solar system that could harbour life is an extraordinary one hundred billion – give or take a few of course. This number is difficult for the human mind to imagine even while gazing out on a starry night, but how about the fact that the universe is probably in the region of 100 billion light-years in diameter, and that just one of those light-years is the equivalent to 9.5 trillion km (5.88 trillion miles). 

With such mind-bending sizes, it’s not hard to understand why so much time and effort has been put into the search for extraterrestrial life – and don’t forget that the universe is still expanding. 

The Early Days

In the late 19th and early 20th Centuries, much of the attention fell on our neighbouring red planet, Mars. Nicholas Tesla, and later Guglielmo Marconi, both believed that with the use of wireless electrical transmission we would be able to speak with our Martian friends. Both at one point believed that had picked up transmissions that could be from Mars – but alas, they were not. 

Between 21st and 23rd August 1924, Mars moved closer to the Earth than it had been for the previous century, and would be again for the next 80 years – surely this was the moment the Martians would contact us. An excited buzz rippled across America and a National Radio Silence Day was promoted across those days, with people encouraged to turn down their radios for five minutes at the top of each hour. At the same time, a huge radio receiver attached to an airship was lifted 3 kilometres (1.9 miles) above the United States Naval Observatory in Arizona, where it waited expectantly. To give you an idea of how seriously this was all taken, the head cryptographer of the United States Army was waiting at the ready to translate any potential Martian messages. 

If this sounds a little a rudimentary, things picked up in 1960 with what we would consider the first modern SETI experiment. Project Ozma was carried out by astronomer Frank Drake in conjunction with Cornell University and was the first time distant planetary systems had been studied through interstellar radio waves. 

With the help of a telescope measuring 26 metres (85 feet) in diameter, Drake focused his attention on two stars, Tau Ceti and Epsilon Eridani near the 1.420 gigahertz marker frequency – a quiet section of the electromagnetic spectrum known as the water hole. A 400-kilohertz band was scanned around this area, with a single-channel receiver at a bandwidth of 100 hertz. In total, 150 hours worth of recordings were taken over a four-month period that was analysed after. Hearts must have skipped a beat on 8th April 1960 when a signal was detected, but this was soon deemed to be a false flag and perhaps an aircraft travelling overhead.  

The Soviets also got in on the act during the 1960s and carried out numerous searches using omnidirectional antennas in the hope of picking up a signal, but it was definitely in the United States that the search seemed to be most focused. The first formal, continuous SETI program was established at Ohio State University which began in 1963. The radio telescope, known as Big Ear, measured 103 metres by 33 metres and was paid for with$71,000 in grants from the National Science Foundation. And as I’m just coming to, Big Ear certainly did hear something. 

In 1971 NASA commissioned its own SETI Study which came to be known as Project Cyclops. Though it was never started, the scale of it would have been enormous – with 1,500 separate satellite dishes at an estimated cost of $10 billion ($67 billion today). Project Cyclops never saw the light of day, but the framework would go on to be applied to future SETI programs.

Wow! Signal

OK, back to Ohio State and the Big Ear radio telescope. Now, watching a video about the search for extraterrestrial life can be a little frustrating – for the quite obvious reason that we’ve never actually found anything – and we all know that. If you’re expecting me to announce at the end of the video that we have in fact discovered aliens, well I’m sorry to tell you that that just is going to happen. But occasionally, the universe throws out a small glimmer of hope, and that was exactly what happened on 15th August 1977. 

A few days later, astronomer Jerry R. Ehman was going over the recorded data when he discovered something extraordinary. Among the ones, two and threes scattered around the page, which represented the chaotic nature of radio signals, something appeared – 6EQUJ5. This was not a message in itself, but rather an intensity variation over time. 

This six-digit form that had appeared in the computer readout represented a signal that astronomers believed had come from the constellation Sagittarius and what’s more, it had lasted for the full 72-seconds that Big Ear was capable of observing it. The telescope had a fixed position so it relied on the orbit of the Earth to scan the sky, so whatever the signal was, it could have gone on for longer than 72 seconds. Ehman scribbled Wow, next to it on the page, and the name stuck.

If you’re wondering why you’ve never heard of this, it’s probably because countless attempts to find the signal again have failed. Countless hypotheses were put forward, but no definite answer has ever been discovered. And to this day, it remains one of, if not the, most likely candidate for an extraterrestrial transmission.  

The 80’s and 90’s

The U.S, and in particular its congress, made a habit of flip-flopping back and forth with SETI programs throughout the 1980s and 1990s. NASA’s first serious SETI endeavour had its budget cut in 1981 only for it to be restored the following year. 

In 1992 however, things really got going with the Microwave Observing Program (MOP). This would be a long-term survey that would carefully search 800 nearby stars using radio antennas used by the NASA Deep Space Network, as well as the 43 metres (140-foot) radio telescope of the National Radio Astronomy Observatory at Green Bank, West Virginia and the 300 metres (1,000-foot ) radio telescope at the Arecibo Observatory in Puerto Rico. The signals gathered by all three would then be analysed using spectrum analysers, machines that could cover 15 million channels each.  

But just one year into the program it faced ridicule from within the U.S congress, with some viewing it as little more than a huge waste of money. Interestingly, many of the uber-religious congressional members within the house who have long believed in an omnipotent presence above us found the search for extraterrestrial life a little too far to believe. And make of that what you will. 

But the program motored on without government funding and in 1995 the SETI Institute of Mountain View, California essentially brought the entire program back to life, but this time under the name of Project Phoenix. As of 2012, the yearly budget for the program was $2 million – with roughly ten times that spent on all SETI programs around the world. 

There are countless SETI programs underway around the world and far too many to go into in great depth. The world’s first radio observatory built with SETI as a primary goal is China’s enormous Aperture Spherical Telescope (FAST), which consists of a fixed 500 metres (1,600 ft) diameter spherical dish. Both Berkley and UCLA universities in California have SETI programs, while Project Argus, which brings together a global network of amateur radio telescopes, falls under the SETI League, a non-profit organisation set up in 1992 with 1,500 members across 62 countries. There are currently 143 Project Argus telescopes in operation in 27 countries. If you’re wondering about the name Argus, it comes from a mythical Greek beast who was said to have 100 eyes – so quite an appropriate name.     

Active SETI

While the majority of SETI programs have been focused on monitoring radio signals, some have taken a much more active approach. Instead of hoping that aliens are sending signals to us, why not send signals out to anybody listening – something that has come to be known as METI (Messaging to Extra-Terrestrial Intelligence) – or active SETI. 

Sending messages out into space in the hope they might be picked up by somebody – or something – obviously comes with plenty of dilemmas. In what form do we send a signal? Words, music and even images have all been considered, but even then, how can we be sure that whoever receives it knows how to interpret it? 

The first message to be sent was done so through Morse Code, from the Evpatoria Planetary Radar in Crimea and directed towards Venus. In typical Cold War-style, the all-important message was – Mir (meaning both peace and world) – Lenin – CCCP – as in the Russian spelling of the USSR. Unfortunately, Venus never wrote back. 

The Arecibo Message which left Earth in 1974 was a little more complex. The radio message consisted of seven parts that were designed to showcase human achievement rather than any meaningful attempt at communication. It included:

  • numbers from 1-10
  • atomic numbers of the elements hydrogen, carbon, nitrogen, oxygen, and phosphorus, which make up deoxyribonucleic acid (DNA)
  • The formulas for the sugars and bases in the nucleotides (organic molecules) of DNA
  • The number of nucleotides in DNA, and the double helix structure of DNA 
  • An image of a human, the physical height of an average man, and the human population of Earth. 
  • An image of the Solar System, with a clear marker as to where the message had originated from.
  • A graphic of the Arecibo radio telescope, from where the message was beamed out from.

The message was directed at the globular star cluster M13, located around 25,000 light-years away. There was of course again no response, but it did receive some fame when a hoax crop circle appeared in 2001 in the UK, which copied the entire message in a field near the Chilbolton radio telescope in Hampshire, UK. 

In 2012, a response to the Wow Signal was sent that included 10,000 Twitter messages as well as videos from various celebrities carrying individual messages. The most recent attempt was the Sonar GJ237b, composed of 38 different 10-second pieces of music each submitted by a different musician. The destination is GJ237b, an exoplanet 12.4 light-years from Earth that scientists believe at least has the potential of being inhabited. The message is due to arrive at the plant on 3rd November 2030.   

In total, 19 different messages have been sent out across the universe since the early 1960s. The practice has come in for some criticism for the slightly bizarre reason that it would essentially give away our location. As if there are some devilish extraterrestrial beings out there just waiting to go all Independence Day on us if only they could find us!

One exciting idea that has been bounded around is that of a 10 billion watt interstellar SETI beacon that would essentially send out millions of individual beams across the universe. When it was first put forward in the 1980s, it was dismissed as being impossible, but scientists believe this could happen now. A study carried out in 2018 estimated that a 1 to 2-megawatt infrared laser beamed through a 30 to 45-meter telescope could be seen from as far away as 20,000 light-years. Proponents of this idea say that once two civilizations have successfully found each other through this method, we could switch to other technologies to continue communication. Sounds simple enough.  

The Great Unknown 

A recent development has been the search for technosignitures which are signs of life such as city lights on planets, space mirrors, atmospheric contamination, space crafts – and even a Dyson Sphere, which we did a video on here on Megaprojects. This is done by monitoring the light, heat and chemicals emitted by planets, often using infrared telescopes or satellites or gamma-ray observatories.

There are so many exciting possibilities out there, but as I mentioned at the start of the video, without the scientific proof it all comes to very little. The debate over extraterrestrial life has grown much further than simply do they or don’t they exist. With the continued failure to find anything concrete, it has led many to question why. Are our efforts simply too primitive? Could one, or multiple civilizations have already died off? German astrophysicist and radio astronomer Sebastian von Hoerner has stated that the average duration of civilization is 6,500 years so it may simply be a case of the right place at the wrong time. Or do they simply want nothing to do with a polluted, war-like planet like our own? 

To those who believe this is a huge waste of time and money, this will all sound like the ultimate clutching at straws, but this is a search that is not going to end any time soon. As our technology improves, our gaze becomes further and more concentrated. Human ambition to comb the universe is stronger than ever with our innate curiosity leading us to unprecedented levels of scientific research in the hope of answering that tantalising, yet elusive question – are we alone?    

The search for extraterrestrial life continues.

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