Finding it is one of the  greatest dreams of mankind: Extraterrestrial Intelligence (ETI). While our solar system has been well explored and Mars even been chosen by many researchers as one of our future homes, human desires for discovering outer space are still growing. Are there any aliens? And if so, what do they look like? How do they communicate with each other – and do they know that we humans exist?  Novels, art and pop-culture have dealt with this topic for many years. In 1897, the US-american author H. G. Wells released his book „The War of the Worlds“, in which a conflict between mankind and an extraterrestrial civilization arose. In other novels, aliens were depicted  as a sort of animal, for example in Francis Flagg's “The Lizard-Men of Buh-Lo”“ or insect-like alien enemies of Robert A. Heinlein's “Starship Troopers”. Of course, Hollywood also well-known blockbusters  such as „Alien“ or the legendary movie ”E.T – the Extra Terrestrial”–  just to name a few.

These questions also keep Douglas Vakoch busy. The American researcher has been focusing on SETI – the Search for Extraterrestrial Intelligence – for over 40 years.  The term SETI comprises various scientific projects that have been carried out in the United States since the 1960’s, many of which Vakoch was a part of. This can mean exploring radio waves of the electromagnetic spectrum for signals from an Extraterrestrial intelligence (for some wavelength ranges, there are special terms due to their characteristics or their use; the visible light is a small part of the spectrum) . The astronomer and astrophysicist Frank Drake started the first modern SETI experiment, Project Ozma, in 1961. The aim was to detect interstellar radio transmissions. In this frame, he used a Green Steel Observatory radio telescope – it’s diameter measured 26 metres – to study two stars, Tau Ceti and Epsilon Eridani. Both are eleven light years (100 trillion kilometres) away from the Earth. Drake was also responsible for the Arecibo message, which was sent from the Arecibo-Observatorium (the second largest radio telescope worldwide) in Puerto Rico in 1974. Nevertheless, the two projects weren't successful, meaning: no interstellar signal was detected.

For sixteen years, Vakoch has worked as the Director of the Interstellar Message Composition at the SETI Institute. In 2015, he became the  President of METI, a nonprofit research and educational organization dedicated to transmitting intentional signals to nearby stars. With Forbes, Vakoch spoke about his work at METI, what aliens could look like and what his next projects, which should finally detect ETI, are.

You created a first interstellar message (a series of two-dimensional pictures) as a high school student: Your inspiration came from Frank Drake. Where does your personal motivation for the search for ETI come from?
My personal hope is that by discovering another form of intelligence in the cosmos, we will be able to hold a mirror up to ourselves, helping us better understand which aspects of Homo sapiens reflect universal aspects of intelligence – and which are unique to our species. On a personal level, I am continually intrigued by the complexity of the challenge to understand an independently evolved species, separated by the vast distances of interstellar space.

What was the reason for the establishment of METI?
For many years, the major SETI organizations have debated whether we should transmit messages to extraterrestrials, but none was willing to take the initiative. When we launched METI as an independent organization, our goal was to promote research in astrobiology and SETI that other organizations weren’t addressing. The most notable of these is sending intentional, powerful signals in an attempt to receive a reply – Active SETI. But METI as an organization is also promoting research in other areas. Other SETI groups have begun optical SETI observations, but these typically use a few very large telescopes. In contrast, METI is developing a global network of moderate-sized telescopes that will give us opportunities for follow-up of a signal around the world.

Similarly, many universities have research programs to discover exoplanets around other stars, and to understand the origins of life. Both of these are critical to understanding the prevalence and distribution of life in the universe. But there are other areas that are equally important, but relatively neglected. Biologists and psychologists study intelligence in its varied forms on Earth, but there’s been little work to draw on these insights to try to anticipate the nature of intelligence on other worlds. When METI held its first workshop in 2016, we focused on exactly this question, in the process advancing work that was being ignored by other organizations.

One of your principles is that mankind should act “first” when it comes to sending intentional signals. This, in order to start a communication with ETI. Why should we be the first-movers? Isn’t it enough to wait and receive potential signals?
One of the great misconceptions about METI is that we have given up on passive SETI. Nothing could be further from the truth. We also conduct ongoing optical SETI observations, and if we detect a series of brief laser pulses from another star from our observatory in Panama, for example, we could make first contact as soon as tonight, without ever having sent a signal. So some extraterrestrial civilizations maybe sending us signals, and we should continue to search for them. But other civilizations may be doing exactly what we have been doing so far – simply looking and not transmitting. Our intentional signals are intended for this group – the civilizations that are staying quiet until receiving an invitation to make contact.

Among some astrophysicists, it seems to be common sense that life in space actually exists. The components that are needed for that, like water or carbon, are abundant and any planet – that has reasonably viable living conditions – offers life a chance. How does it come that we never received a signal from Extraterrestrial Intelligence or found proof for it?
Over the past couple of decades, scientific discoveries make is seem all the more likely that there is life elsewhere in the universe. A quarter of a century ago, we did not know of any planets around another star except for our Sun. Now when we look up at the night sky, we know that virtually all of the stars we see are circled by planets. So there is a lot of real estate out there that might be inhabited. When we look at the space between the stars, we see complex organic molecules that are the building blocks of life on Earth. The raw materials for life are abundant in the universe. When we combine those two facts – there are a lot of places that life could live, and the „stuff of life“ is everywhere – it seem inevitable that there should be life somewhere in the universe besides Earth.

So, why haven’t we discovered any extraterrestrial life yet?
We have only just begun to be able to detect the atmospheres of exoplanets. As we place the next generation of powerful space telescopes in orbit above Earth in the coming years, we will have increased abilities to detect the telltale signs of microbial life in the atmospheres of the planets around other stars. But that will need to wait a couple of decades. Right now, we’re not capable of detecting extraterrestrial bacteria unless it’s in our own solar system – and that requires expensive space missions to the other planets and moons.

But why haven’t we detected any radio signals from advanced extraterrestrials? After all, the first SETI search was conducted in 1960. The fact that we’ve been searching for artificial signals from other civilizations for over a half century, can lead us to believe we’ve made more progress than we have. Astronomers have looked carefully at a few tens of thousands of stars for artificial signals in their SETI searches, and this is out of the hundreds of billions of stars in our galaxy alone. So we have only searched a tiny fraction of all stars, and so far, we have found no evidence of technological civilizations. So the easiest explanation for why we haven’t yet found other intelligence in the galaxy is that we haven’t looked at very many places. But another possibility is that we haven’t gotten any signals from other worlds because they are doing what we are doing: simply listening, and not transmitting.

What could another species or civilization look like?
There’s no reason to think that an alien intelligence will look anything like humans. There is no reason to imagine that an extraterrestrial intelligence will have gone through a similar series of steps, yielding intelligence that shares a basic body plan with humans. If we make contact, we are more likely to share certain dispositions than body shapes. We can expect intelligent aliens that we make contact with to share our curiosity about the universe. We can also expect a certain amount of shared technology. Unless they use astronomical equipment that lets them detect our radio or laser signals, we won’t make contact in the first place. We may have a greater cultural overlap with extraterrestrials than we have biological overlap.

You stated that this year you want to send signals either to Proxima Centauri b as the Earth's nearest star or – if the researchers had to operate from the northern hemisphere – Gliese 411. Why will these projects do better than, for example, the Arecibo-message sent in 1974?
When we send messages to other stars, we target the stars in our galactic backyard. It would take just over four years for our message to reach Proxima b and another four years to get a reply. The time would be about twice as long for an exchange with any denizens of the Gliese 411 system. It would take just over eight years for them to receive our message, and a total of sixteen years for a roundtrip exchange. While that might seem like a long time by human timescales, it a blink of the cosmic eye when compared to the Arecibo message’s time to get to its target: the globular cluster M13, located 25.000 light years from Earth. That means if we get a response to the Arecibo message, it won’t come for 50.000 years.

The Arecibo message was a one-off effort. In contrast, we send our signals across multiple days, giving an SETI scientists on another planet a chance to coordinate observations with other astronomers, so they can confirm our signal. That’s what we try to do on Earth as we follow up putative SETI signal detections, so we can rule out false alarms, and we want to give extraterrestrial astronomers a chance to do the same on their worlds. There was no such follow-up with the Arecibo message, which to aliens could seem similar to the Wow! Signal detected at the Ohio State University SETI program in the 1970s. The Wow! Signal was seen only once, and never replicated, so it isn’t convincing as a real signal from extraterrestrials. If aliens go to all the work to detect our messages in the first place, we want to be sure they can convince their colleagues that they’ve really discovered life in the universe.

What has to be done differently in comparison to the Arecibo message?
Even though the message was brief, lasting only three minutes, it was encyclopedic in intent. It included information about our counting system, a description of chemical elements essential to life on Earth, a diagram and chemical analysis of the structure of the DNA molecule – which carries the genetic information of all life on Earth. But the Arecibo message didn’t stop there. It described what we humans look like, including how tall we are and the population of Earth. It described the structure of our solar system, and even sketched out the antenna dish that was used to transmit the message. My concern is that by trying to communicate so much, the result may be a garbled mess that makes no sense at all. In contrast, our messages are much simpler, focusing on a few key mathematical and physical principles needed to describe radio waves themselves. Our hope is that by providing more details about a few central concepts, we can create a message that is more intelligible to the alien recipients.