The History of the Search for ET life – so far

The Allen Telescope Array in Hat Creek California is set up to search for signs of extra-terrestrial intelligence (Image source: Sky & Telescope)


For millions of years – as long as humans have existed and gazed upwards –  people will have questioned are we alone in the Universe? Yet, it is only in the past 60 years or so, with rapid technological advances, that it has become possible to make serious attempts to answer that age-old question.

Listen to interview with Myles Dungan on The History Show, RTE Radio 1 (broadcast 2/04/17)


The ancient Greeks, the foundation stone upon which much of our western way of life today has been built, were the first, in the west at least, to consider the possibility that the Universe was infinite and that it contained an infinite number of civilisations.

The arrival in the 16th century of the Copernican model of our Solar System, where the Earth revolved around the Sun, impacted on our thoughts of ET life too.

This radical science, which place the Sun at the centre of the Solar System, not the Earth, implied that our planet was not perhaps as important as we had thought.

If Earth was just one planet of several orbiting the Sun, and not at the centre of everything, then why could there not be life, like us, on other similar planets?

This, of course, caused complications for some established religions, as if there was life, like us, on other planets, then had Jesus come down to save them too?

There things stood, with lots of questions, but no ability to answer them, for several centuries until the second half of the twentieth century.


In the 1950s, at the height of Cold War paranoia, the number of reported sightings of UFOs increased dramatically across the United States.

In 1959, two young scientists at Cornell University decided to try and take a serious scientific look at how mankind might try to tune in to alien communications.

The paper appeared in Nature, one of the world’s top scientific journals, and it was called ‘Searching for Interstellar Communications’.

This paper changed everything because it established the scientific principles by which scientists might try to find, and listen in to alien communications, if they existed.

The authors, Guiseppe Cocconi and Philip Morrison were both physicists based at Cornell University in upstate New York. They said that the possibility of extra-terrestrial ‘intelligent’ life couldn’t be determined, or ruled in or out. However, given that mankind evolved it was likely that other intelligent creatures evolved too, on planets near a Sun. Some of these civilisations might, the authors said, be more advanced than our own and may want to contact us and other intelligent beings that resided on planets – like them – close to a warm Star.

The two physicists considered how intelligent extra-terrestrials might make contact with us, and decided that electromagnetic waves, which travel at the speed of light and are not easily knocked off course, would be the most logical way to transmit a message.

Furthermore, they decided that the most likely frequency the aliens would broadcast on would be 1,420 megahertz as that is the ‘emission frequency’ of hydrogen, the most abundant element in the Universe. This is the frequency of the radio wave emissions given off when an atom in an element, in this case hydrogen, is given off as the element moves from a high energy atomic configuration into a lower energy configuration.

The aliens, the logic went, would chose this frequency because they knew other intelligent beings would also understand its importance and tune in accordingly.


The paper inspired a now-famous astronomer called Frank Drake to perform the first scientific experiment to search for extra-terrestrial intelligence. That was 1960.

Drake, is still alive, aged 86, and an active astronomer, and considered the Father of SETI the Search for Extra-terrestrial life, and the SETI Institute in the USA.

Drake pointed a radio telescope at two ‘nearby’ stars called Tau Ceti and Epsilon Eridani to see whether there was anything being broadcast from planets orbiting these Sun-like bodies in the hydrogen emission frequency from that location. There wasn’t.

Today, the SETI Institute, based in Northern California, has access to a $30 million array of telescopes, funded by Paul Allen, the co-founder of Microsoft. It has a permanent staff of scientists, and is supported by donations and computer power by SETI enthusiasts all over the world. It is not reliant on US taxpayers’ support.

Drake, apart from founding SETI, is also famous for producing something called the Drake equation along with Carl Sagan, to predict how many civilisations there might be in the Universe, based on known parameters.

In 1961, when the Drake equations was first produced, it predicted there was from 1,000 to one billion such civilisations, and the range was down to the fact that the parameters were nebulous.

The Drake equation has become more accurate over the years, based on better knowledge of parameters such as how often Sun-like Stars form, and how many of these stars have planets. But we still don’t know how precisely life begins, even on Earth, or what fraction of life will evolve to become intelligent.


The implications of the Cocconi and Morrison article took time to be absorbed by the mainstream scientific community, but eventually, in 1971, NASA got on board by setting up Project Cyclops at NASA. This was the first formalised, publicly-funded research project into searching for ET life.

The funding wasn’t enough for scientists at Cyclops to do a great deal, but even at its low level of funding, it soon came under political attack.

In 1978, Senator William Proxmire bestowed one of his infamous ‘golden fleece’ awards on the SETI programme, deriding it as a waste of taxpayers’ money.

In 1981, a Proxmire amendment killed off SETI funding for the following year with Proxmire saying that it was a silly search for aliens unlikely to produce results.

In 1993, NASA got back into SETI work, this time with the High Resolution Microwave Survey Targeted Search programme. But, again, this project too came under political attack and lost is operational funding just one year after it began.

It wasn’t just politicians who were critical of SETI work, scientists were critical too, who supported the view outlined by the late nuclear physicist Enrico Fermi.

Fermi, who had died in 1954, did not accept the view (held by many at SETI) that the Universe was teeming with life, based on its size, and number of planets near Stars.

Fermi said that if the SETI people were to be believed, and the Universe was teeming The Earth was 4.5 billion years old, Fermi had said, and there was no evidence of extra-terrestrial life visiting here in all that time.

He had asked the question if there is so much life out there, ‘where is everybody’. It was a simple, yet, devastating riposte to the Drake equation.

Fermi had come up with his idea in 1950, but many scientists still point to it.


Yet, Fermi was not alive when two things happened, both in the mid-1970s, which are the best pieces of evidence for the existence of extra-terrestrial life.

The first story concerns an experiment that took place when the Viking landers landed on Mars in 1976. Some readers will remember the amazing colour pictures of the surface of Mars shown on TV at the time.

Viking 1 and Viking 2 were NASA space probes sent to Mars for the sole purpose of determining whether life existed on the planet.

One of three experiments on board worked was set up to see if the soil contained microbes. If it did, the life forms in the Martian soil would ingest and metabolise the nutrients and release either radioactive carbon dioxide or methane gas which could be measured by a radiation detector on the space probe.

The minute the nutrients were mixed with the soil sample there was a huge reaction with something like 10,000 counts of radioactive molecules being produced. This was a huge spike because the radiation background on Mars was 50 or 60 counts.

The experiment was, thus, positive for life, but NASA did not announce it had found life because the other two experiments on board which were negative for life.

The other piece of ‘evidence’ that is put forward concerns what is called the ‘Wow signal’, which was received by the Big Ear Telescope on 15th August 1977. The telescope was scanning for signals coming in from potential ET intelligent beings.

This was a strong narrowband signal which appeared to come from the constellation Sagittarius, and was in the 1,420 MHz frequency band. It was precisely the sort of signal that the SETI researchers were looking for as being of ET origin.

Jerry Ehman, a volunteer astronomer working with SETI spotted this massive, powerful, narrow band Wo signal on the paper readouts he was going through while sitting at his kitchen table a few days later.

Ehman was stunned by the signal and was so taken back by it that he wrote the comment ‘Wow’ in the paper margins, hence the name Wow signal.

The signal lasted 72 seconds, then the Earth rotated, the signal dropped out of view of the telescope, and when the same region of sky came into view again, it was gone.

The signal helped inspire the film Contact (1997) starring Jodie Foster.

Jerry Ehman went through every conceivable possible earthbound source for the signal, such as nearby military and civilian communications, but nothing could explain it. It remains the strongest candidate ever detected for an alien radio transmission.


The biggest thing to happen in recent years was the announcement in 2015 of $100 million privately funded search for ET life over 10 years, or about 10 million per year. This is big even compared to the annual funding for SETI of about 2 million dollars per annum. The Breakthrough Listen and Breakthrough Message initiatives are supported by the Russian internet investor and physicist Yuri Milner and supporter by big names like Stephen Hawking, Martin Rees and Frank Drake.

This will survey the one million stars in the Milky Way closest to Earth, as well as the 100 closest galaxies for signs of intelligent life beyond Earth, in the form of artificial radio or optical transmissions that cannot be explained by natural phenomenon.

The advance of technology and our ability to scan more areas of our vast galaxy and Universe mean that people like Seth Shostak, an astronomer at SETI believes that we will have discovered ET life, intelligent or not, inside the next 20 years.

Get ready to meet ET!

Earth twin, and billionaire funds shorten odds of finding ET intelligence

Click above to listen to discussion about how the odds of finding extra-terrestrial life have improved with Keelin Shanley on Today with Sean O’Rourke (Broadcast 28th July 2015)

Parkes Telescope

New funds from a Russian billionaire will give ET hunters more time on large radio telescopes such as this one; the Parkes Telescope in Australia (Source: Wikipedia)

Ever since humanity emerged as an intelligent species here on Earth, people have wondered whether we are the only intelligent creatures in the Universe? Or whether other intelligent beings exist somewhere out there?

It is a huge question for our species, and our identity, yet finding an answer to it has never been placed at the top of any political or scientific agendas.

Many politicians and scientists believe it is a waste of time and money to search for so-called ‘little green men’ when there are so many problems here on Earth that need attention and resources.

Some leading scientists, including Stephen Hawking, have also, in the past, questioned whether it is a good idea for us to make contact with an alien intelligence that may have superior technology to ourselves.

We can think of what happened to Africa, when the Europeans ‘made contact’ with Africans in the 19th century.

And there is a risk, Hawking has said that we could end up like the Africans did after contact with Europeans; exploited, enslaved, or even wiped out.

Assuming an ET intelligence is ‘benign’ could be the worst, and last mistake mankind every makes.

There is, Hawking has said, an argument that we would be better off not just to stop seeking contact, but to ignore an alien signal even if one should come our direction.

But the main problem facing the tiny number of top scientists who have dedicated their careers to finding ET is a lack of funding. The lack of funds has meant that we are little further down the road to answering the question Are we alone? than we were 50 or 60 years ago at the dawn of the Space Age.

Some dedicated ET-seeking scientists, have even begun to ask the question, was it still worth it, given the lack of success since the Search for Extra-Terrestrial Intelligence (SETI) began with the setting up of the SETI Institute in 1960.

After all, as one leading astronomer has pointed out, despite 55 years of listening for signals from ET, scientists have been met with nothing more than ‘An Eerie Silence’.

Into this atmosphere of pessimism, came news just last week that an Earth-like planet Kepler 452b had been discovered by NASA’s Kepler telescope.

This planet is 60 per cent larger than Earth, with a similar surface temperature; it has twice the gravity, lots of sunshine, probably liquid water, a rocky surface, and a 385-day year.

It is very like the Earth, and all the conditions exist for life to develop there. Also, it is 6 billion years old, 1.5 billion older than Earth, so there has been even more time for life, even intelligent life to evolve there.

This is just one of many Earth like planets that the Kepler telescope is discovering in the Milky Way, so there is lots more Kepler 452b’s out there.

Kepler cost $600 million when it was launched in 2009 and has found thousands of exo-planets since; planets that are outside our own Solar System, and some of these, like Kepler 452b, have conditions that allow for life.

Allied to this, came the news that Yuri Milner, a Russian billionaire is to pump $100 billion of his own funds into the search for ET intelligence.


 Yuri Milner is a 53-year-old Russian, science graduate turned entrepreneur with an estimated personal net worth of $1.8 billion.

He studied theoretical physics at Moscow State University, graduating in 1985. In 1990, he went to the US to do an MBA after reportedly being disappointed in himself as a physicist.

Milner made a fortune through his early involvement in a Russian email service, the group, and investing in Facebook and Twitter.

He was inspired as a child by reading ‘Intelligent Life in the Universe’ by Carl Sagan, listening to the inspiring speeches by President John F Kennedy, and watching Neil Armstrong and Buzz Aldrin walk on the Moon as an 8-year old.

This is not the first time that a wealthy private investor has come to the rescue of resource-starved ET hunters. In 2001, Paul Allen, the co-founder of Microsoft, provided $30 million in funding for the Allen Telescope Array, a linked collection of telescopes north of San Francisco dedicated to the search for ET.

Allen was the eccentric character depicted by John Hurt, some might remember in the film Contact, which featured Jody Foster, playing the role of astronomer Eleanor Arroway, based on real life ET hunter Dr Jill Tarter.

Allen’s investment was remarkably, but Milner’s investment is more than triple that, and is a game changer for scientists searching for ET intelligence.


The story begins really in 1960, when legendary astronomer Frank Drake, set up the SETI, or Search for Extra-Terrestrial, Institute in California.

Drake is still alive, aged 85 now, and actively involved in the SETI Institute’s work, which has the mission statement to “explore, understand and explain the origin, nature and prevalence of life in the universe.”

From the start it was decided to focus on trying to pick up radio signals from space, which could only have been generated artificially.

It was thought more likely, for scientific reasons, that an alien civilisation would transmit at certain frequencies, so these frequencies became the focus of the search, while many others were ignored.

So, SETI was limited in its scope from the start, by a lack of funding. It was directly funded by the US taxpayer for a time, but this stopped in the mid-1970s. Since then it has been reliant on funds from private donors, big and small.

Wow signal 

As Murphy’s Law would have it, a few years after SETI’s Federal funding was cut, one of its researchers, a man called Jerry Ehman, who was now working on SETI project without pay, made perhaps the most important discovery in the history of the search for ET.

On August 15, 1977, a huge, and apparently artificially produced radio signal was ‘heard’ by the Big Ear Observatory in Ohio. This showed up in the data later read by Jerry Ehman. The signal was immensely powerful, lasted about 90 seconds long, and came from an uninhabited area of deep space.

All man-made possible radio sources were ruled out systematically by Ehman and his colleagues, but the signal never repeated and there the mystery was left.

Famously, Ehman wrote the word ‘Wow’ beside the data which showed the massive pulse on the paper printout, as he read through it in amazement.

I managed to track the now retired Ehman down last year, as part of an RTE Radio 1 science series called What’s It All About? He spoke to me about his experience, and he still thinks about the Wow signal every day, 38 years later.

It remains mysterious, and was the inspiration for the contact made by alien intelligence depicted in the Hollywood film contact, based on a book by Carl Sagan and staring Jody Foster.

The reason, SETI researchers would argue has to do with the size of the Universe, and the lack of resources put into the search up to now.

Most scientists now accept that given the size of the Universe and the number of earth-like planets that exist out there that can potentially hold life, that life, and intelligent life – mathematically speaking – simply must exist elsewhere.


Consider the figures:

There are an estimated 11 billion earth-like planets in the Milky Way alone which could hold life. And, there are 100 billion galaxies in the Universe.

To many scientists, those numbers suggest one thing: Life and lots of it.

Yet, given the vast distances involved with space, ET life remains elusive.

But, it’s perhaps a bit like trying to find a needle in a haystack somewhere in the Soviet Union, but we don’t even know which haystack the needle is in yet.

Frank Drake, whom I mentioned before, famously came up with the Drake Equation in 1961 to estimate, using mathematics, and the number of active, communicative extra-terrestrial civilisations in the Milky Way galaxy.

Drake estimated that there would be between 1,000 and 100,000 such civilisations in the Milky Way. The Drake equation has its critics, who argue over the mathematical parameters used to come up with its conclusions.

However, perhaps the most powerful argument against Drake, and the entire SETI enterprise came from the physicist Enrico Fermi.

Fermi looked at the Drake equation, made some calculations of his own, and came up with something which became known as the Fermi Paradox.

The Paradox is that if there was such a high probability intelligent ET civilisations out there, as Drake proposed, then why Fermi asked, was there no evidence of human contact with them?

Fermi put forward the simple, provocative question ‘Where is everybody?”

Stephen Hawking

 The involvement of Hawking is interesting and significant because of his former statements, as I mentioned earlier, about the wisdom of seeking contact with alien intelligences.

Yet, Hawking’s presence, certainly helps to add scientific credibility to the initiative and guarantees lots of press coverage, as huge press coverage follows whatever Hawking does.

Hawking said to British press in 2010:

“We should be wary of answering back, until we have evolved,” said Hawking. It “might be a bit like the original inhabitants of America meeting Columbus. I don’t think they were better off for it.”

But Hawking has obviously changed his mind for whatever reason, as the Milner projects will involve both passively looking for signals coming from space, and actively seeking to compose messages which mankind ‘might’ (it has to be discussed further) decide to send out into space.

Hawking now says it is right that we should seek out other civilisations as we can learn things from them, such as how to best use and allocate natural resources.

The other interesting thing about Hawking worth mentioning here is that he believes that life spontaneously arose on Earth.

This is at odds with many reputable scientists who now increasingly believe that life was ‘seeded’ here following comets or asteroids slamming into the Earth.


There are two initiatives called ‘Breakthrough Listen’ and ‘Breakthrough Message’.

Breakthrough Listen is, by far, the more important of the two.

It will search for life on planets orbiting the some 1 million stars, like our Sun, which reside in our own galaxy the Milky way. It will also search for life in the 100 galaxies closest to the Milky Way.

Breakthrough Message, meanwhile, will fund an international competition to determine the content of messages that we humans want to send to alien civilisations. This is open to everyone – what would you like to say to an alien civilisation? And there is prize money of $1 million for the best messages.

This is probably more to do with public relations and winning the public over to get interested and involved in the search for ET intelligence.

Most of the $100 million will be used over the next 10 years to buy expensive telescope time on the Green Bank Telescope in west Virginia USA and the Parkes Telescope in Australia.

The ET intelligence researchers plan to use that telescope time to examine up to one million ‘relatively’ nearby star systems for artificially produced radio signals which would indicate the presence of intelligent life.

The funding will also enable researchers to develop new receiving technologies which can speed up the search for radio broadcasts across a wide spectrum of frequencies and from many locations of the sky.

Aside from searching ‘local’ stellar targets, the researchers will also look at a large number of galaxies beyond our Milky Way for signs of very advanced intelligence which may be capable of sending signals across inter galactic distances. This would require immensely powerful transmission technology.

The money will also be used to look for laser flashes, which can also indicate the presence of an advanced civilisation.


Last year, I interviewed Seth Shostak, a highly regarded researcher with the  SETI Institute and he answered that exact question. He has worked in the field all his life, and is in a good a position to make a prediction.

Seth has said publicly that he believes that we will have discovered signs of an intelligent extra-terrestrial civilisation by about 2040. By then, he said, astronomers will have scanned enough star systems to give themselves a great shot of discovering alien-produced radio signals.

At that point in time, scientists will have scanned about one million star systems, instead of the few thousands which have been scanned to date. Seth made this prediction even before the Milner funding came online.

I’m guessing that he would probably revise his date several years downward after this latest news, which he no doubt is elated by.

In the next 25 years it’s likely we’ll live to witness the historic discovery of an ET civilisation.

We will have finally discovered that we are not alone.

I could envisage that for our grandchildren, the discovery of new ET civilisations will become humdrum, and that ‘contact’ will be the next milestone sought.

What’s It All About? on RTE Radio 1, The Search for ET (Episode 2)

Seth Shostak

Seth Shostak, pictured above, an astronomer with the SETI (Search for Extra-Terrestrial Intelligence) Programme believes that evidence for ET will be found in the next few decades [Picture Credit: SETI]

Did you ever wonder where ET might be hiding? What he might look like? When we might find him? What the ‘real ET’ might say to us, and us to him, if we made contact? What would be the likely consequences on Earth from ET phoning us?

These are some of the questions myself Sean Duke, and Colette Kinsella, explored here in episode 2 of the four part series What’s It All About?  for RTE Radio 1

Click HERE to listen

This week’s contributors:

Professor Andy Shearer, Director of the Centre for Astronomy at NUI Galway acts as our celestial guide as we voyage into the vastness of space. Andy explains that even at light speed it would take 4 years for a signal to reach Earth, even from our nearest Star, Alpha Centauri. From other more distant parts of our Galaxy, it would take a signal, again travelling at light speed, hundreds of thousands of light years to reach us here.

Then, beyond that, there exists hundreds of billions of other galaxies, some of which would take hundreds of billions of years for light to reach. This is not even including the strong possibility that our Universe is just one of many more Universes that are in existence.

Dr Jerry Ehman an astronomer working at the Big Ear Telescope in Ohio discovered a radio message, apparently from deep space a few days after it was received by the telescope close to midnight on the 15th August 1977. This became the now legendary ‘Wow signal’.

According to Dr Ehman, an astronomer working with the SETI (Search for Extra-Terrestrial Life Programme) this had ‘all the attributes of a signal from an extra-terrestrial civilization’.

The signal arrived in at 1420 megahertz – a frequency that has little natural interferences – and lasted for 72 seconds before disappearing again.

The now retired Dr Ehman talks here, almost 37 years after his famous discovery. He says the signal still today cannot be explained by any man-made, or natural sources and it has remained mysterious.!_signal

Seth Shostak, senior astronomer at the SETI Institute explains how the search for ET has progressed over the decades and what the prospects are now for finding ET.

Seth believes that a signal from ET will be found in the next few decades thanks to science’s growing ability to search faster and more accurately.

He is often asked at parties whether ET might just NOT be out there. His replay is that this is akin to proclaiming – after searching 1 square mile of Africa and finding no elephants – that there are no elephants in Africa.

Professor Paul Davies is a British astronomer based in Arizona. He believes one of the reasons why the search for ET has yielded nothing but ‘An Eerie Silence’ (the title of one of his books) is because we don’t know what to look for.

The likelihood, according to Paul, who is Director of the Beyond Centre at the University of Arizona, is that ET might be post-biological. In other words and advanced civilization might have cast off the shackles of biology, and become some kind advanced, non-living, super-intelligent system.

We have been looking for ET in our own image, says Paul, and that’s a mistake, as we have to imagine the imaginable to successfully find ET.

Paolo Nespoli, a highly experienced Italian astronaut, who has spent a lot of time on the International Space Station (I.S.S.) describes what life is like in space..

This is a weird world, in which micro-gravity has a marked effect on the body, causing wasting of muscles and bone, as the I.S.S. constantly ‘falls’ at 8km per second.

Paolo, who spent months onboard the I.S.S. said that the speed the station travels at means there are 16 sunrises and 16 sunsets each day.

He maintained contact with the world, by telephoning his family each day, and there was Internet (albeit very slow) which he used to send tweets, pictures of space and even do his taxes online.

Professor Anthony Murphy, NUI Maynooth, describes the darkness and numbing cold of space, where temperatures hover just above ‘absolute zero’.

This is a place, he says, where nothing can be heard, and it would not be possible to speak as there is no air to carry sounds. If a person was transported to space they would be frozen and asphyxiated instantly.

Dr Brian Caulfield, UCD, is working to develop technology to help humans stay healthier for longer in space.He is working with a company called Biomedical Research to develop a machine that can help prevent muscles from wasting, increase calorie burn, and heart rate, in order to limit the damaging effects of micro-gravity.