Two world-leading astronomers discuss their search for life beyond our Solar System.
In the last 60 years, humankind has made great strides in our search for extraterrestrial intelligence (SETI). But will we ever be successful?
In this episode, Tom is joined by Professor Steven Tingay and Dr Chenoa Tremblay – who recently scanned 10.35 million known stars in the deepest and broadest search ever for extraterrestrial technologies – to discuss what progress has been made.
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Intro:
This is The Future Of, where experts share their vision of the future and how their work is helping shape it for the better.
Tom Robinson:
Hello, I’m Tom Robinson. The first interstellar Search for Extraterrestrial Intelligence took place in West Virginia, in 1960, when astronomer Frank Drake looked towards two nearby stars for signs of radio signals. Today, our radio telescopes can scan far more than a couple of stars. In September this year, radio astronomers here in Western Australia conducted the deepest and broadest search ever for extraterrestrial intelligence at low frequencies. Using the Murchison Widefield Array, they scanned part of the Vela constellation, known to include 10.35 million star systems. While the search came up empty, it has meant we are now one tiny step closer to answering the question: “Are we alone in the Universe?” To discuss this topic, we have the two researchers behind this survey. We have the newly crowned Western Australian Scientist of the Year, Professor Steven Tingay, who is the Deputy Executive Director of the International Centre for Radio Astronomy Research. And, postdoctoral researcher Dr Chenoa Tremblay, from Australia’s science agency, CSIRO. Thank you both for coming in today.
Dr. Chenoa Tremblay:
Thanks for having us.
Professsor Steven Tingay:
Pleasure. Nice to be here.
Tom Robinson:
What makes this recent search for extraterrestrial intelligence so significant?
Professsor Steven Tingay:
Well, I think a bunch of different things. So as you noted in the intro, it's the broadest and deepest survey yet, and therefore takes the biggest chunk yet into what we would call the observational parameter space that is the total volume of search space that we have to cover in order to perhaps find extraterrestrial civilisations.
Dr. Chenoa Tremblay:
Yeah, absolutely. I mean, the survey went out to... First, we can look at it just to target already known exoplanets. So places where we already know there are planets existing, but that's actually a fairly small number in comparison to the number of stars that actually exist. And there is a concept around that if you look at the number of stars that are about the size of our sun, about 10 per cent of them could have planets that are Earth-like or Earth in size. And so that means there's a lot that we're missing by just targeting various star systems and exoplanets. So by using the nature of the Murchison Widefield Array, and its very large field of view, we're covering much larger volumes of stars than previously had looked at. Plus we're targeting a slightly different size of wave that most people look at as well.
Tom Robinson:
Obviously, this is a big search, 10.35 million is a lot, but is it a drop in the ocean? Is there more stars that you could be looking at as well?
Professsor Steven Tingay:
Well, our galaxy in which we live contains billions and billions of stars, so 10 million out of multiple billions is a very small fraction. So yeah, it is a drop in the ocean almost literally. So one of the things we note in our paper is sort of to try and put that into context. So if that entire search space was represented by the Earth's oceans, we're talking about searching about a swimming pool worth of water out of the ocean. So it really is almost a drop in the ocean. Having said that what we did was a hundred times better than anyone had done previously and the previous best were also us. So what we're doing is proving up techniques that will allow us to go further and deeper as we develop more powerful telescopes. And the next step in that progression is the Square Kilometre Array.
Tom Robinson:
When you do these surveys, what exactly are you looking for?
Dr. Chenoa Tremblay:
I mean, for us, we're not a hundred per cent sure what we're going to look for or what it's going to look like. It's like asking a toddler to go find an object in the house and they very excitedly go and look and wander around and run around and look under the couch. And then they come back with big eyes and go, "What does it look like?" We just aren't a hundred per cent sure what it's going to look like. So we use models in our understanding of the cosmos and what the signals have looked like so far to be able to use it to narrow down that search space and what it is that we're looking for.
Dr. Chenoa Tremblay:
So in general, we were looking for intense signals that show up in very narrow wavelength ranges, and it could be anywhere within the electromagnetic spectrum. So it could be a smart one. It could be a fairly large one, but the benefit of looking at lower radio frequencies or very long wavelengths is that they pass through the Earth's atmosphere so we can build ground-based telescopes. They are traveling through dust and gas that might be within the galaxy. So that means we can probe much further in larger distances than if we're looking at much higher energies or smaller wavelengths.
Professsor Steven Tingay:
Yeah. This is one of the more fun things about undertaking SETI is that you have to free yourself from your human-based assumptions. So even people who've been working in SETI for a long time; when you're discussing ideas about what to look for, how to look for it, people will often say, "Oh, but of course aliens, wouldn't do it like that." And my response is, "Well, how do you know?" Life is so varied and different on Earth from species to species. How do we know how an extraterrestrial civilisation would communicate among themselves or to an external civilisation like ours?
Professsor Steven Tingay:
So what assumptions do you bring to the table about how they communicate? Why they communicate? Et cetera. So it's really interesting to free yourself from the sort of human-based assumptions that as humans, we have two arms, two legs, various senses, and we react to various things in various ways. There's absolutely no reason why another intelligent life form elsewhere in the universe would act anything like the same manner. So I try and look at it in a really unbiased sense. What's the total parameter space that we can cover in any way? And how can we cover that in order to free ourselves from those assumptions?
Tom Robinson:
Am I right in thinking that if a signal was detected, it would be at least thousands of years old?
Dr. Chenoa Tremblay:
Not necessarily. So we actually do have stars that are hundreds of light years away, and we do probe that space as well as thousands and even greater, potentially. So it doesn't mean that it has to be that old, but it can be that old, but that's the great thing about radio waves is that they survive all of that time and through all of that space.
Professsor Steven Tingay:
And there are some really nearby stars as well, that likely have planets. So you're talking about turnaround times in communications of possibly, small numbers of decades. That almost becomes interesting. You could have a text message back and forth a few times in your career.
Tom Robinson:
How does the search for extraterrestrial intelligence help us? What's the purpose of doing this research?
Dr. Chenoa Tremblay:
I think that everybody wants to know the answer. Are we alone? It has inspired generations, whether it's through stories or our movies, or just the dreamers, or the scientists. And so inspired by that, we can do it along the way. So the great thing about the science is that we don't have to dedicate the time to just that. And a lot of my research is actually focused on looking for the molecules, the early signs of the potential for life, even before they might be old enough to signal for themselves or to communicate with us in particular. So that's the great thing I think about some of this type of work.
Professsor Steven Tingay:
Yeah, I agree. We've talked about the search being a drop in the ocean. So taking out a drop at a time, it's pretty systematic work, but you never know it might be that next drop that contains the magic signal. And it's also become a lot easier as well. So with the Murchison Widefield Array, we can survey massive chunks of the sky very efficiently and in parallel with other science. So the way Chenoa and I started on this, and this is what our third or fourth paper?
Dr. Chenoa Tremblay:
This is the third one, yes.
Professsor Steven Tingay:
In the series?
Dr. Chenoa Tremblay:
Yeah.
Professsor Steven Tingay:
Started out as Chenoa pursuing PhD work to look for the signals from molecules and us realising that we could repurpose the data to do SETI. So we sort of get two bits of science for one, and any time you can do something like SETI for almost free, you should do it. And it's a very high return, low effort route at that stage, which means that you could strike it lucky, and it hasn't really cost you all that much along the way. So that's almost a perfect scenario for science in my book.
Tom Robinson:
How do you know where to look? Is it a case of looking everywhere or are you quite targeted and specific with these surveys?
Dr. Chenoa Tremblay:
For us, for our surveys, they were targeted towards interesting areas for other science in particular. And like Steven had said doing the SETI searches at the same time, gets benefit of being able to look at these large patches of sky in various different locations and look and see, do you see something different? And even going back to seeing the same patch of sky, because we don't know what the signals are going to look like, or when they might come, if they're periodic, then we can tag along onto those. And so we don't have to worry about the targeted approaches, which is something that some SETI searches do because their field of view is much smaller. So they have to be much more focused as to what it is that they're doing. But for us, we can do a lot more random.
Professsor Steven Tingay:
Yeah. Yeah. I was up in Kalgoorlie on the weekend and we spent a bit of time looking for gold, me reliving my childhood. And my dad used to say, "Gold is where you find it." Which is true. And I think the same is true for life. Life is where you find it. So you should look everywhere and anywhere. We first looked towards the centre of our galaxy, where there are mountains of stars, there's a lot going on. And then we looked in the opposite direction in the Galactic anticentre direction. And now we've looked at a particularly interesting part of the plane of the galaxy. So since you can't really predict, I think almost any direction as good as any other direction. So again, try and be unbiased.
Tom Robinson:
You mentioned before the Square Kilometre Array. Could you explain to me what that is?
Professsor Steven Tingay:
Well, if people have Googled Murchison Widefield Array at this point, then the SKA is a much bigger version of that. So it's going to be the largest and most complex radio telescope ever conceived. It's actually going to be two telescopes, one based in South Africa and one here in Western Australia with a headquarters in the UK. It's around about a two billion Euro project over a 10-year construction period. And we're due to start construction next year. In Western Australia, the telescope will consist of approximately 130,000 individual antennas spread out over a radius of about 65 kilometers up in the Murchison.
Professsor Steven Tingay:
So it's an enormously large scale and complex piece of infrastructure built out in the Murchison to be away from humans and interfering radio signals from things like mobile phones, microwave ovens, all sorts of electronics, which by the way is bad news for SETI because some of the city signals may look similar, but it will be built to explore basically the entire history and evolution of the universe back to when the first stars and galaxies were born less than a billion years after the Big Bang. So it's pretty all encompassing.
Tom Robinson:
Wow. So in terms of research like scanning the Vela constellation, will you be able to get a bigger scope for these kinds of surveys? Will you be able to look further into space?
Dr. Chenoa Tremblay:
Yeah, I think it will do a bit of everything really. It has the potential to allow us to locate things better, so much better sensitivity towards small objects. It allows us to probe deeper and just in general, be more sensitive because your sensitivity has a lot to do with what your noise threshold, how low can a signal, or how weak can a signal be before you can actually detect it or say with any certainty that you can detect it? So having something like the square kilometer array will allow us to go further and go a little bit deeper and prolong this understanding a little bit better.
Tom Robinson:
As you said before, you just don't know. We've never had contact with extraterrestrials before, but I suppose hypothetically, could they be looking for us?
Professsor Steven Tingay:
Yeah, I mean, yes, absolutely. If we exist and we are looking for others, then I think it's reasonable to say that if other civilisations exist, they may be doing the same thing. And that actually forms the basis for some sorts of SETI searches. So if another civilisation was looking for us or indeed undertaking the sort of astronomical studies that we are undertaking, what sort of observations would that lead them to do? And how could we maximise our chances of being found? So as well as looking for signals from others, you can send signals out and that's been done using various radio telescopes to broadcast the signal off into space. Of course, we've been doing this inadvertently for many decades now. So there are episodes of I Love Lucy, 50 plus years out into space that some civilisation on some planet may be receiving now and thinking, "Well, this is interesting. What does it all mean?"
Tom Robinson:
If you found a signal, if someone was looking for us or projecting signals and you found out what would happen next, where would your research go?
Dr. Chenoa Tremblay:
Well, I mean, I think the first thing that you always want to do with a new discovery is try to confirm it. So either re-observing using the same telescope involving broader community, things like that, I think would be really important.
Professsor Steven Tingay:
I mean, who do you tell first? So I've thought about this probably an unreasonably large amount against the chances of actually finding anything. But it's an interesting thought exercise. What would you do? So in the past, various people have found various signals – the famous Wow! signal, which turned out to be nothing. So as Chenoa says, confirmation is the first thing. So I think we'd want to convince ourselves first. So you'd want to try and observe the same bit of sky and do the same measurements maybe without giving away, even to your colleagues, what you're doing and when you've convinced yourself. Yes. Good question. Who do you call next? Because you could imagine unleashed upon the world and all the different peoples and cultures and points of view about various things that this could be disturbing news to some people, exciting to a lot of people, but I'm not sure I could predict what the overall reaction might be if you are able to demonstrate conclusively that alien civilisations existed. I mean, you've seen the movie Contact, right?
Tom Robinson:
Yeah.
Professsor Steven Tingay:
So I think that's not a bad illustration of the variety of outcomes that-
Dr. Chenoa Tremblay:
There was actually a study done in 2018 as to what is the prediction of the outcome. And it was done by a group of radio astronomers and psychologists, and they surveyed people and they put out a scenario of detection and what they came up with results was really fascinating. They said that anybody they contacted said they themselves would be very excited by the possibility of contact and the fact that we found somebody. But everybody's point of view was that our civilisation as a whole would be scared and wouldn't know how to react. And so I found that really fascinating from a sociological standpoint is that if everybody says, "Yes, I would be excited, but I don't think my neighbor would be." I think that's really interesting.
Professsor Steven Tingay:
That is interesting. So maybe the search for extraterrestrials actually tells us more about ourselves than anything else.
Tom Robinson:
Well, that leads into my next question. It can be hard to predict as you say, what the ramifications or the reaction would be if we discovered extraterrestrials. What do you think would be the ramifications if you could confirm that there are no extraterrestrials? If you could somehow confirm that we are the only civilisation, what's the ramification of that?
Professsor Steven Tingay:
Yeah, well, there's the good old absence of evidence is not evidence of absence. So proving that something doesn't exist is quite difficult. So maybe they're in a different part of the spectrum. Maybe they don't even bother communicating. Maybe it's a collective intelligence. There's nothing to say that anything has to be based on an individual, communicating with another individual. That's a very human centric look at the world. I think you could easily imagine some sort of collective planet-wide intelligence that doesn't actually feel the need to communicate with anyone. Again, there's this sort of external projection of communication, maybe a very human centric thing. So proving that something doesn't exist is actually really difficult. I think we'd have to take a much, much bigger slice out of the observational parameter space before you could start saying that you're worried that you're the only thing going in the Universe, so that will take quite a long time.
Tom Robinson:
In some ways, could it be easier to find extraterrestrials than prove that there are no extraterrestrials?
Dr. Chenoa Tremblay:
Yeah, I think so. Because I think at the same time, our technology for being able to probe those parameter space is also improving. So to not only just say, yep, we covered all of the bases, well, then we've improved our technology to be able to do these searches. So therefore we could go through the whole entire exercise over again. And that's an almost infinite iterative process.
Professsor Steven Tingay:
Yeah, absolutely. I always find the Hitchhiker's Guide to the Galaxy very, very instructive when thinking these things through. And if people are familiar with the rise of Deep Thought, the computer and the philosophers were worried it was going to put them out of business until Deep Thought revealed to them that you've actually got centuries of working, arguing amongst yourselves before I come up with the answer. So there's always bigger questions to answer, and there's always more work to do that's science, but at some point, yeah, it might be the case that we actually detect something. And once you've detected it, you've got something real there rather than just limits on existence.
Tom Robinson:
Does other research into extraterrestrial life, like the recent announcement that there might be a microbial life in Venus's atmosphere? Does that impact your research in any way?
Dr. Chenoa Tremblay:
Not really impact it, but does kind of broaden it in some ways. I mean, because one of our goals is also to study and look for the early biomolecule tracers and stuff in other atmospheres, a lot of these searches we're searching for things within our own planet and I'm taking these further and looking for planets in other solar systems. So I'm reaching deeper, but the knowledge that's gained here provides some of the information and detail to help limit maybe what I'm looking for in other planetary systems. So I think it's quite complimentary.
Professsor Steven Tingay:
Yeah. I think it also illustrates nicely a few of the things that we've been talking about here. So Venus is really close to the Earth. It's got an atmosphere, there's all sorts of things going on in Venus, in its atmosphere, but for decades and decades and decades, the statement was, "Oh, it's too hot. It's too hostile." Which again is an incredibly human centric view. And so appearing on Twitter every now and then now is these predictions or statements from the '50s, or '60s about what might happen in the cloud deck of Venus, but these were all discounted.
Professsor Steven Tingay:
And despite being the closest place to look, it's sort of more or less been ignored. Mars has been a much bigger pool because a hundred plus years ago, someone said that the lines that they saw on the surface of Mars were canals and that just made Mars the place to think about for life. And it may turn out that it is subsurface water and all sorts of interesting things going on, on Mars, but Venus has been ignored and now, okay, so there might be some form of life on Venus after all. And in hindsight sort of make sense.
Tom Robinson:
I mean, as you sort of mentioned, who do you tell first? If you found extraterrestrial intelligence, would you tell us? Would it get covered up, do you think? Would it be the greatest scientific discovery in human history? Or, would it be part of ongoing government operations perhaps?
Dr. Chenoa Tremblay:
I think it would depend on who found it and how it was found in some ways. I mean, I think that's a really complex question in general, but I mean, if we have a scientific discovery and we can't explain that discovery so to speak and SETI is one of the possibilities and we have history of this, even more recent history of this, then yes, it would probably be brought to the broader scientific community. Steven mentioned the Wow! signal, that's probably one of the earliest signals of unknown origin that has been widely contested and tried to be checked in various different ways. And more recently, I guess, fast radio bursts or these intense pulses that are coming from other galaxies that we can't explain, SETI was one of the options for that as well. So I think it depends on the situation in which it's detected and exactly what the type style of that signal is and how it would be handled. But if it is done through research and it's a signal we don't understand, I could see easily just being more open to the broader community.
Professsor Steven Tingay:
Yeah. I think SETI is like everything else in that the principles of scientific investigation should be applied. So if you've found something interesting, well, you want to verify it for yourself as far as you can. At some point you need independent verification. I think that's where it gets interesting because who do you go to next to help you with that independent verification without putting it on Facebook? Or, announcing it to the world via Twitter? Who do you trust to do that? So it's probably be an exercise of sort of building out the knowledge and the team and building up the evidence and understanding that as far as you can. And so a thing in science is that you find something interesting, you verify it, you try and build a model around it or reconcile it with a theory or something like that.
Professsor Steven Tingay:
And at some point maybe it doesn't all fit together, but you've sort of exhausted your knowledge and your tools. And at that point you shouldn't lock it away or discount it. You should just publish it and put it out there to the community. And so it's always an interesting thought experiment to, when do you do that? And almost certainly when you put something out, you've made a mistake or you've overlooked something, but the process of science is that transparency and having different sets of eyes on it. And at the end of the day, being prepared to be wrong. It's not SETI: it's some molecule that no one's heard about before. And upon deeper investigation, that's all reconciled.
Professsor Steven Tingay:
But there are some really clear, easily identifiably giveaway signals that something would be a true SETI signal. So the planets orbit around a star, which will change the frequency of the signal that you receive in a very predictable manner. And you can also attempt to decode signals. You can attempt to break them down to their constituent components. So things like that would be the killer app in determining if something was likely a techno signature from an advanced civilisation.
Tom Robinson:
Something's just occurred to me. It sounds like quite a process between that first discovery of a signal say, and then the absolute 100 per cent confirmation that it is from another planet, basically. So could that, and it's purely speculation really, but could that process take what months, years to get from A to B?
Professsor Steven Tingay:
Decades. Could easily take decades. Many things in science take decades or a hundred years.
Dr. Chenoa Tremblay:
Yeah, I think they said that the phosphine you mentioned, the Venus. I think between that confirmation and that process before they put out that first paper, took a couple of years, because it was the first thing, but it's kind of weak. Let's get time on another telescope. Let's check with that. Do these things line up? Do they line up with all of the other information that we have? Like, it's been around the Earth, does it... Not, around the Earth, around the sun and does that coincide with the right velocities and expectations in the shifts of the signals and stuff like that. So from an initial standpoint to the first time where it's become more known to the world could be a couple of years. But Steven's right, it can take decades before anybody thinks, "Yeah, that's it. Or no, it's not."
Professsor Steven Tingay:
The bigger, the result, the more comprehensive you have to be with evidence. So if you're going to claim or even suggest that something is a signal from an extraterrestrial civilisation, you had better have done every single test and dissect your data in every possible way and covered every possible base that you can before you even contemplate suggesting that to the world. I mean, that's a responsibility on science and that's the scientific process. And there's lots of examples of people who've claimed big results, but upon just a little bit more analysis, have been shown to be completely wrong. So scientists don't like looking like idiots by announcing big results and then being immediately told it's wrong. We try and do better than that.
Tom Robinson:
Well, it sounds out we're at the start of quite a long process. I think that's all we have time for today. Thank you Steven and Chenoa, for sharing your knowledge on this topic today.
Dr. Chenoa Tremblay:
Thanks for having us.
Professsor Steven Tingay:
Thanks, Tom.
Tom Robinson:
You've been listening to The Future Of, a podcast powered by Curtin University. If you have any questions about today's episode, you can get in touch by following the links in the show notes. Don't forget to like, comment, and subscribe. Bye for now.