Astronomy Cast

Ep. 110: The Search for Extraterrestrial Intelligence

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You know what this show needs? More aliens. Since we don’t seem to have any visiting right now, we’re going to have to find some. SETI is an acronym. It stands for the Search for Extraterrestrial Intelligence. But there’s more to SETI than just putting up a radio telescope and hoping to catch a glimpse of an alien television broadcast.

  • Ep. 110: The Search for Extraterrestrial Intelligence
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    Fraser Cain: You know what this show needs?

    Dr. Pamela Gay: I don’t know. What does it need?

    Fraser: More Aliens. [Sigh] Since we don’t seem to have any visiting right now, we’re going to have to find some. SETI is an acronym that stands for the Search for Extraterrestrial Intelligence.

    But there’s more to SETI than just putting up a radio telescope and hoping to catch a glimpse of an Alien television broadcast. Pamela, with SETI – I’m sure people have heard quite a lot about this – people who have seen UFOs and think that they’re being abducted all the time, but there is legitimate Science being done to search for Aliens.

    And that is SETI. So, what is sort of the history of the search for Aliens?

    Pamela: Well it basically occurred to people that we’re sending out radio signals all the time. As we generate television, as we generate radio the signals are traveling out into Space and getting carried off to nearby Stars.

    It’s possible that there are other societies out there, other civilizations out there and they might also be working in radio. They might also be perhaps even shooting laser beams our direction; pulses of radio light in our direction.

    And maybe just maybe we can find those other civilizations by just going out and looking at the nearby Stars that just might be capable of having Planets that support life.

    Fraser: Right so here on Earth we’ve been broadcasting in radio signals for the last 50 or 60 years and those signals are moving away from the Earth at the speed of light.

    So, there is a sphere 60 light years on a side – where the radius is 60 light years – that if you’re inside that ball, that sphere, then you would be able to detect signals coming from Earth.

    If you’re outside of that then our signals just haven’t reached that point yet.

    Pamela: What’s scary is I think we’re both feeling our age because it was in the 1930s it was basically more than 70 years ago that the first television signals went out. So, we’ve been sending things out for a long time and those signals could be now hitting a lot of Stars.

    Fraser: Right, that sphere holds probably hundreds if not thousands of Stars.

    Pamela: And so some of these Stars do have Planets. We KNOW some of these Stars have Planets – we just don’t think they have habitable Planets yet because what we’re seeing is hot Jupiters.

    Fraser: Then in vice-versa, there could be Alien civilizations that have been around for thousands or even millions of years who have been broadcasting like this and maybe are broadcasting through the entire Galaxy. It only takes like 60,000 light years to get from any point of the Galaxy outside. So you can imagine they have a big transmitter and they are able to reach every point of the Galaxy.

    Pamela: In 1960, Cornel University Astronomer Frank Drake – the guy who brought us the wonderful Drake equation to try and figure out how many Alien citizens there just might be out there on Alien worlds – went out and made the first modern SETI experiment called Project Ozma after the queen of Oz from the Wizard of Oz series. He didn’t find anything.

    What I find amusing is one of the Stars he looked at Epsilon Aridante actually has a Planet going around it. So even back then before we knew that there was a Planet there he was out there looking to see if there could be life in that system. He also looked at Calseti and it was a start. Since then we’ve looked at thousands of Stars.

    What makes SETI a reasonable expenditure of money is as you’re out there looking at all of these nearby Stars, you’re gathering data on how these Stars are behaving in radio light. This is data that can be used for scientific explorations as well.

    It’s not completely a waste of telescope time. It is telescope time that is spent going “okay, radio quiet, okay, still radio quiet.” But we’re learning the characteristics of all of these different Stars in radio light.

    Fraser: What exactly is a SETI researcher looking for?

    Pamela: In general what you’re looking for is a burst of intensity that you’re scanning across the Sky listening to Bland radio Star, Bland radio Star and then all of a sudden you see a signal that’s either higher intensity or has a pattern to the signal that’s coming off of it that’s not just noise.

    Television signals, radio signals, all of these have modulations in the signal that your radio and television are able to turn into voices, music and pictures. As you’re listening to these Stars, what you’re looking for is changes in the modulation of the radio that are not nonsense, not white noise but have statistical significance. You can then go “aha, this just might have meaning” and try and come out of it, tweeze out of it with some sort of a coherent signal. The question is as we start thinking about perhaps we can start sending signals out and help our own Planet be discovered, what sort of signals might we be looking for? Anyone who has paid attention to how they encode the new Hi-Definition Television Signals knows that there’s been all sorts of arguments over how do you encode it; how do you phase the data.

    Anyone who has done graphics knows that there’s multiple ways to compress an image. Once we find something that looks coherent, it’s going to be a matter of reverse-engineering the format of essentially this intergalactic file that has been sent towards us.

    Fraser: Right, okay if you point your radio telescope at a Star today – even the Sun – you’re just going to get a sort of a cracking popping random fluctuation that should stay within a very normal parameter, right?

    Pamela: Tune your radio or television to a channel that doesn’t exist. What you experience is what we get when we look at something that is giving off white noise.

    Fraser: And so, if there was some kind of intelligent signal happening then it might still sorta seem like white noise but there will be a pattern to the noise that will say “okay, there’s no possible way that nature generated this pattern.”

    Pamela: Right, we’ll get something that we may not understand but we know this isn’t completely random. You can imagine someone rolling 8 different weighted dice.

    You’re going to notice that “wow, these don’t behave quite right” but if you’re mixing up which dice is which one each roll, it’s going to take you awhile to sort out how the 8 different dice are weighted.

    Fraser: Okay, so what does the modern search for extraterrestrial intelligence look like?

    Pamela: SETI has been forced to struggle. It used to be that they were funded in part by NASA. Now they’re completely funded through private donations. Since 1994 NASA hasn’t spent any money on the search for extraterrestrial intelligence. They’ve only spent money on astrobiology which is basically the search for extraterrestrial microbes.

    What the SETI Institute out in California has done is they work to raise money to build the Allen array a radio telescope system that is going to be dedicated strictly to the search for extraterrestrial intelligence. There has also been other one off projects.

    For instance Harvard has a project that is piggy-backing on the back of one of their optical telescopes and as the telescope goes about doing its normal research this instrument that’s mounted on top is looking for pulses of laser light that might be coming from other Stars.

    Fraser: That strikes me as crazy that there’s no Science funding for this search. I mean it’s kind of like THE most important question you could possibly ask scientifically.

    Why is that? Why is there not official backing and the poor folks at the SETI Institute have had to go and do pledge drives and raise money from private individuals.

    Pamela: It’s politics. Far too many things come down to that very simple sentence. It’s politics. There are crazy people out there – many of us know some of them – who believe they’ve been abducted by Aliens, they believe they’ve been probed. They believe things that we have no scientific way of testing to say “yes you are right” there’s no evidence to say “yes you are right”.

    These people have given the entire Search for Extraterrestrial Intelligence Program a really bad rap. So when Congress is out there and Senators and Representatives are trying to get on their high horse and say that we’re spending money appropriately, they will often go through NASA, the National Science Foundation, and the National Institutes for Health expenditures and start pulling out things that have names they can make fun of.

    For instance, when I was at McDonald Observatory, we had a project called HEMP which stood for the Hobby-Eberly Telescopes Echo Mapping Project. It was a project to map the cores of Galaxies with actively feeding Black Holes. They saw the name HEMP and the project almost got cancelled.

    Fraser: Hmm… Poor naming choice.

    Pamela: Yeah. So, SETI – Search for Extraterrestrials, little ETs – that’s easy to make fun of sort of the way McCain has been making fun of the Adler Overhead Projector. The name and what’s being funded – well what’s being funded is significant. You can name something silly and make fun of it.

    Fraser: Okay so before I interrupted you, we were talking about the Allen Array. How does the Allen Array work?

    Pamela: The Allen Array is still in the process of getting built. It was formerly called the One Hectare Telescope. It’s paid for by Paul Allen which is where the name comes from. It’s in northern California.

    This system is going to have 350 radio dishes on it that work together. It’s made as much as possible with off the shelf technologies to keep the price low. You can sort of imagine they went out and bought 350 satellite dishes that you might use to get old style pre-dish network, back yard satellite signals for your television. They have all of these commercially available dishes.

    They’ve strung them together in their own miniaturized – but with more scopes – version of the very large array. This allows them to collect a lot of signals. It also means that they’re going to be able to have higher resolution. It means that they’re going to be able to if they want to, tune their dishes to a lot of different frequencies and it also means that they have a lot of redundancy.

    There was one signal caught once called the Wild Signal. It was caught with one telescope and only one of the two detectors on that one telescope was able to catch it at moment. We don’t know if that one signal was real; if it was a fake or if it was something from the Earth or Space.

    With the Allen telescope they will be able to say “yes, this signal was caught by this many telescopes; it was caught this different set of frequencies with all sorts of different types of coverage” and it will allow a better sense of what is real and what isn’t.

    Fraser: If Astronomers have been searching for signals from Extraterrestrials for 30 years, why haven’t they found anything yet? I mean I think maybe that is where the funding is getting cut.

    You’ve been at it for 30 years, how hard is it [Laughter] just to point a radio telescope up at the Sky and point it at all the different nearby Stars and call it a day.

    Pamela: So here where I live in rural Southern Illinois, we don’t have a channel 2. So if I have a television that I bought in Boston where we did have a channel 2, and I came out here and every knob except for channel 2 on my television was broken, I would conclude that there is no intelligence producing television in Southern Illinois.

    And I’d be wrong. The problem is I’ve only done my experiment on one narrow channel. As we search the Sky for signals, for all we know they could be using any one of hundreds and hundreds of different radio frequencies. So we have to look at all of these different frequencies.

    Not only that, but the Sky is a really big place. We have to search all these different Stars and all these different frequencies. We haven’t been doing it continuously for 50 years. The first attempt to detect something was made in 1960. We’ve been hit or miss doing it now and then with this scope and that scope as time is made available.

    There hasn’t been a search of the entire Sky in even one frequency. There are all these different frequencies that we can try looking in. There’s a lot of Space and we’ve only probed a small part of it.

    Fraser: Right so there’s the problem, right? There are hundreds of millions of Stars in the Milky Way and you would have to watch each Star on every single frequency – because you don’t know what frequency the Aliens would be broadcasting on.

    Pamela: And you’d have to do it more than just once. You can imagine someone looks in the direction of the Planet Earth and the moment in time that they capture corresponds to the moment in time that we were behind the Sun.

    So you have to go back more than once to really rule out a Solar System and look for more than a brief instance. All these pieces together means this is a project that’s going to take a long time for us to do.

    It’s something that has to be done in both the northern and southern hemisphere. The Allen telescopes can at least get us the northern hemisphere. But that’s still only half the Sky.

    Fraser: If I remember and I was trying to dig this up before the show and I was unable to find it but Seth Shostak who works at the SETI Institute said that it would take something like the Allen Array or even something bigger working for a few dozen years to do a comprehensive search in the radio spectrum for all the Stars that are appropriate within a certain range of us to really say okay we’ve searched the radio spectrum and we haven’t found any signals. We’ve really right now just scratched the surface.

    It’s almost like decoding the human DNA on one person and now you’ve got to do everybody else. Or like finding Asteroids, NASA feels pretty confident that they have located most of the Planet-killing Asteroids and plotted their locations.

    But there are still millions of potentially dangerous Asteroids out there that they haven’t even found yet. It’s just scratched the surface of this project.

    Pamela: The thing that you always have to wonder about is once you’ve done all of this work in the radio, well what if you’re dealing mostly with societies that never developed radio. What if you’re dealing with societies that went straight to encoding things in microwaves and doing point-to-point communications?

    Fraser: So are there any plans to search for that kind of thing?

    Pamela: Not that I know of but that doesn’t mean they don’t exist The problem with point-to-point communications is it doesn’t exactly leak through the Atmosphere so here you have to start hoping that we’re having signals beamed toward us.

    Fraser: Right I think with SETI the expectation is that we’re not eavesdropping on a civilization that’s just broadcasting television shows. There is a very advanced civilization that has a lot of energy at its disposal and is pumping a lot of that energy into broadcasting a signal out so that it can be heard on another Star. Right?

    Pamela: This is one of the things that I actually find really remarkable. If you use the right color of laser and you focus it using basically a 10 meter telescope – something like the very large telescopes that they have down in Chile – you can focus a laser beam such that a Planet orbiting another Star detects it will see for a brief moment that laser beam appear a thousand times brighter than the Sun.

    So, it actually makes sense for us to not just – if we want two-way communications – to not just go out and listen but to also be beaming signals as we go. It’s kind of a waste of a 10 meter telescope to dedicate it strictly to shooting laser beams out to other worlds, but you can almost imagine a system that observes a Star, observes a Star, discovers a Doppler-shifting Planet and then says “ah, found you!” and beams it with a laser beam briefly.

    Fraser: So are people searching for these beamed laser beams?

    Pamela: There is a program at Harvard University – the one I mentioned earlier – that’s piggybacked on their Optical Telescope and it’s out there looking at thousands of Stars just paying attention while the telescope is off doing its own Science looking for these potential laser beams from other Worlds.

    Fraser: So it’s exactly that, right? We’re hoping that some Alien species has found us, knows that there’s a civilization here and is occasionally zapping at us with a laser beam to see if we’re paying attention.

    Pamela: And even though the Sky is a really big place to try and explore, we can actually increase the probabilities of success on these active projects by looking at how we discover Planets. The places in the Sky that people are most likely to realize “wait that Solar System over there has Planets.” And the places that are most likely to try and actively send us signals are on a very narrow band around the Sky.

    The way we detect Planets is we look for Doppler-shifting of the Sun. With the Sun to be the Alien Sun in this case to be yanked around by its largest Planets causing it to have these wobbles in its motion that we detect a slight variations to the red and blue of individual spectral lines. We also look for Eclipses. We look for the hot Jupiters to pass in front of their parent Star and cause the light to dim in some cases just a hundredth of a magnitude. But we can see these slight changes and if we look at the parts of the Sky where Aliens on Alien Worlds would see Jupiter Eclipsing our Sun would see our Sun’s wobble at its most pronounced due to all of the Planets pulling on it.

    Those are the places that are most likely to know about us if they’re finding Planets the same way we are. We can focus our energy quite literally on shooting laser beams and shooting radio signals at those potential Worlds and increase our odds of having this actually work.

    Fraser: The assumption would be that those Worlds would be doing the same. It’s almost like if we can find Earth-sized Planets around other Stars, then we start zapping at them and we can almost assume that they’re going to be zapping at us. We would do a much better search of those Worlds than some random Red Star. We talked about radio mostly. We’ve talked a little bit about optical. Are there any other ways that maybe civilizations are attempting to communicate?

    Pamela: Well, one way – and we’ve actually done this a bit ourselves – that you can try and communicate to other species is you just send them your junk. Not literally, but if you think about it by the time Voyager One and Voyager Two which both contain information about the Planet Earth on them, by the time they reach other Solar Systems they’re going to be a bit beat up.

    They’re going to no longer really be functioning and just sort of traveling through Space as very technologically advanced pieces of scrap metal. But it didn’t take a lot of energy to put those systems together. As they explored our Solar Systems they did a lot of really great Science. They served a purpose.

    Now they’re just on their way outside of the Solar System. Someday they might get scooped up by an Alien race and they’re carrying a lot of information with them encoded on records and engraved on their surfaces.

    Fraser: I’ve heard that it will take whatever, 77,000 years for the Voyager Spacecraft to reach the nearest Star. If you’re an Alien civilization that’s maybe been around for millions of years, what’s a few tens of thousands of years to do some communicating.

    You can imagine a civilization just going with the absolute lowest amount of energy possible and just hurling very clever little robots in all directions. One per Star and the robot lands and then just starts communicating.

    Pamela: You have to wonder is this a really good way to use resources right now but once we start being able to easily mine the Asteroid Belt, it starts to become much more feasible to think about sending little chunks of rock out in all directions carrying some sort of message.

    This is where we have to start thinking carefully about what sort of signal do we want to send. How do you communicate with someone that isn’t going to have the same basis of language? How do you communicate numbers? There are a lot of very intelligent people from many different fields who’ve gotten together at different points in time to figure out how to encode things.

    What I love most is one of the things that was sent on the record on one of the Voyager missions – I don’t remember which – was the sound of a beating human heart. These are just fascinating things that we’ve decided are representative of our World that we wish to communicate.

    The way that we always come down to settling on how we are going to communicate is with mathematics. So hopefully, some things truly are universal.

    Fraser: Right but I think that if we found an object, we would know right of way that it was made from an Extraterrestrial Intelligence. You wouldn’t necessarily need to communicate but if it was made of something or had properties that we had never seen before.

    Even something sent from our future, like if you sent something made out of Carbon Nanotubes or even things that we’ve only developed in the last ten or twenty years, it would be very indicative to people here that someone else made this. We don’t have this technology yet.

    We talked about Matter being sent, there’s one article that we did on Universe Today a little while ago about civilizations using Neutrinos to communicate.

    Pamela: This is where you have to start getting the civilizations far more advanced than our own. We’re just figuring out how to detect Neutrinos effectively. The idea of communicating effectively with them is still beyond us.

    We know that you can get bursts of Neutrinos from extremely distant sources. Then it just becomes a matter of trying to figure out how to send these things that don’t weigh a lot so if you move it very close to the speed of light that don’t get absorbed really – these things don’t like to react via the electromagnetic spectrum – so you can basically shoot them through Planets and Stars.

    How do you effectively communicate with them and code information in them? Especially with the way they change varieties at will it appears.

    Fraser: Right but as we mentioned these are the nearly massless particles that are streaming out of the Sun right now.

    We mentioned that Neutrinos would go through nearly a light year’s worth of solid lead before finally getting stopped. If you had a way to generate them – I mean don’t we generate Neutrinos in Nuclear Reactors here on Earth?

    Pamela: Right, so we know how to generate them fairly easily. The problem that we have is figuring out how to detect them consistently. You can imagine that you can basically send out smoke signals with Neutrinos where you get bursts of Neutrinos coming through.

    You’re able to detect those bursts of Neutrinos and get information out of the size of the burst. Or other ways perhaps that some advanced civilization will figure out how to encode information in these patterns of arriving really tiny particles.

    Fraser: Now, I had two things that I want to talk about before we wrap this show up. One is talk just for a second about SETI at Home which is awesome. It’s been going for quite a few years now. If you have a computer with some idle CPU time you can install this screensaver called SETI at Home which lets your computer help crunch through all of those gigabytes of data that are drawn down by those telescopes.

    And you can search for some kind of signal from an Extraterrestrial Intelligence which is just great, such a great use of your computer time and processor power so don’t e-mail us we know about SETI at home. [Laughter] We think it’s great.

    Pamela: And it’s FREE!

    Fraser: It’s free, yeah. But I think the last thing I wanted to talk about was: “Is it dangerous for us to be sending signals out into Space?”

    Pamela: I think this is where we start getting into Philosophy and it comes down to the question: “Do you really want to find Aliens?” If the answer is yes, then are you worried that they might be dangerous?

    I’m not so much worried about other Aliens coming and destroying the Planet Earth. I’m probably a little bit Pollyanna in that. But once we discover Aliens, I don’t know what that will do for our society. I don’t know what consequences that will have philosophically. There are religious implications.

    There are so many different things where you can sort of think of the movie Independence Day where you had people on the tops of buildings offering themselves up to UFOs. You can think of the book “Contact” where you had people lining up at the fences of the VLA and yes these were fictions, but I think in this case you have very intelligent writers that imagined what this sort of a discovery would do in our society that has from everyone from the truly crazy to the truly brilliant.

    Unfortunately it’s not an even distribution by numbers across that. I’m not sure we necessarily want to find Aliens right now. Then there is always the issue of if the Aliens just really want to come and take our resources and turn us into slaves.

    Again, I’m not particularly worried about that being likely. Space is a big place. You cannot travel at the speed of light. We’re a long way from the nearest Star that could potentially have a habitable World. So, I’m not really worried about that.

    Fraser: So, you’re not worried about Aliens coming and stealing our resources and turning us into slaves and so on. It’s sort of like it’s just way too expensive to make that trip. [Laughter]

    Pamela: Yes. Exactly, it’s too expensive.

    Fraser: It’s like buying a super tanker so that you can go across a lake to steal somebody’s lunch.

    Pamela: It is in fact more like the Seinfeld episode where they discovered that there is a ten-cent deposit on aluminum cans in Massachusetts. So they rent a truck, fill it with aluminum cans and try and drive them all to Massachusetts to get their deposits back.

    You’re going to spend too much money on gas. Just stay at home and take them to the recycling facility.

    Fraser: Exactly, go mine another Asteroid. Grow another Space Cow. Okay, but then you are worried that you think that our fragile emotional state can’t handle the comprehension that there is another intelligent species out there.

    Pamela: I admit to thinking there will be momentary mass chaos and far too many organizations forming cults. It’s just not something I’m excited to live through.

    Fraser: But should people hide the knowledge?

    Pamela: No. I’m for full disclosure if you find something. I’m for full scientific honesty and openness.

    Fraser: So you’re just kind of bracing for impact.

    Pamela: Yeah, yeah there’s part of me that thinks this is so cool and we definitely need to keep looking. But if we can hold off finding something until I don’t have to deal with the chaos, I’m okay with that.

    Fraser: And I think there would be no chaos. Not only that, it would become mundane. [Laughter] It would be like BORING. Like do we have to hear about those Aliens again and their Alien TV shows? They’re not very good. [Laughter]

    I think that within a very short period of time it would become a very mundane thing. There are so many amazing things that have already happened that we as human societies have incorporated into our psyches.

    We just kinda like whatever, those cars they drive are really fast and people can fly in the air without wings, that any amazing thing becomes mundane very quickly. So I wouldn’t be worried about it at all. Bring on the Aliens.

    Pamela: But for now, I’m going to maintain that I’m a very strong proponent of WETI and a proponent of SETI but not perhaps strong….

    Fraser: Oh, WETI, that’s right. We’ve totally forgotten to talk about WETI. Let’s talk about WETI which is the [Laughter] last kind of search for Extraterrestrial Intelligence. So what is WETI?

    Pamela: WETI is: Waiting for Extraterrestrial Intelligence. Just sort of hanging out, sitting on your sofa waiting to see if the Extraterrestrial Aliens show up. It’s the effortless action committee is the way they put it. [Laughter]

    Fraser: So don’t build Spaceships, don’t build telescopes, don’t send signals, Matter or build Neutrino detection devices, just sit on your sofa and wait for some Alien to come in and sit down beside you and ask for a beer.

    Pamela: Exactly this is my way of searching for Aliens every day of the week. I am totally a member of WETI and in fact, you can sign up to be a part of their effortless action committee on their website.

    I’m for SETI – they’re getting really good science out of what they’re doing. If we do find Aliens, well okay, but it’s important knowledge. It means something to know if we are or aren’t alone in our Galaxy. We can’t answer that question if we don’t look.

    Fraser: Yeah, I think that if I were in charge of priorities, I would make the search for Extraterrestrial Intelligence one of the highest possible priorities. Personally I would throw a lot of resources at both SETI and things like the Terrestrial Planet Finder which would be searching for Earth-like Planets orbiting other Stars.

    That is the most fundamental important question in Science right now is: Are we alone? To find out, why not just listen and see if we can find them. If we don’t find them, that’s fine.

    That tells us something, that life is rare and that our Earth and our civilization are rare and we have a duty to preserve life and peace and try to help explore the Universe. It’s like if you find out that the Universe is populated with tons of civilizations and they’re all busy then it takes a little of the pressure off of us to keep life going. [Laughter]

    But if we can’t find a signal then I think that means a lot to us and shows that we have a lot of responsibility as a __35:26 race in the Universe to get out there and explore and do our job.

    Pamela: While SETI is out there actively looking for Extraterrestrial Intelligence, NASA through many of its different programs and the Astronomy community through many of its different programs are looking for ways to look for plant life, microbial life and looking at the imprints of just organic life forms affecting the Atmosphere in which they live.

    We’re trying to define new ways as we’re finding these new Planets orbiting other Stars to say yes, that World clearly has something affecting its Atmosphere. Yes there is life out there. I hope we really find that type of life in the next ten years.

    Fraser: And we can so let’s just do it. So stop cutting the Terrestrial Planet Finder.

    Pamela: Yeah, build it and Darwin.

    Fraser: Yes, Darwin. Oh if I could run NASA. [Laughter] All right, thank you Pamela and we’ll talk to you next week.