In the summer of 1950, the Nobel-winning physicist Enrico Fermi, mulling over the problem of extraterrestrial life, posed the question, "Where is everybody?"
We inhabit a universe of perhaps 1022 stars. And yet, after four and a half decades of listening, SETI still hasn't picked up any alien transmissions. In the wake of recent research on Galactic Habitable Zones, and the publication of the book 'Rare Earth' by authors Peter Ward and Donald Brownlee (Springer-Verlag Telos, 2000), speculation is growing that intelligence, indeed, life itself, may be rare or even nonexistent beyond our own third rock. Stephen Webb's fascinating book, 'Fifty Solutions to the Fermi Paradox' (Praxis, 2002), includes a number of possibilities supporting the argument that we may well be alone. Like Webb and others, well-known British SF author Stephen Baxter leans toward that conclusion; whereas David Brin, who has written about the subject at length in scientific papers and popular articles, concludes that "it might turn out that the Great Silence we're experiencing is like that of a child's nursery, wherein adults speak softly, lest they disturb the infant's extravagant and colorful time of dreaming."
Norman Spinrad, in his stunning 1974 novella 'Riding the Torch', speculated whether we, as a species, could endure the knowledge that we are alone; similarly, Ian MacLeod's brilliant 'New Light on the Drake Equation' examined the attritional effect of the same terrible doubt on a single individual. And in his January 2004 Asimov's column, Robert Silverberg—who nonetheless believes life and intelligence are likely both commonplace in the universe—wrote wistfully about the vanishing likelihood that even if we do eventually make 'contact' (in the strict SETI sense of the word, e.g., we hear and decode a signal from the stars), the iron laws of physics and the sheer scale of the universe will preclude any type of interactive dialogue.
Can we detect strains of all-too human impatience in these voices? Is interstellar contact, like fusion power, and the completion of the Seattle monorail, always just a decade or two in our future?
There are some optimists. Robert Reed, in his daring story 'Oracles' (Asimov's, January 2002), examined a best-case SETI contact scenario. In the very near future, we intercept and decode a signal of immense power from an alien civilization that loves to brag of its achievements. Along with a myriad of technological marvels, the message gives the location and broadcast frequencies of thousands of other extraterrestrial civilizations, propelling us headlong into a future which—while realizing every SF fan's wildest dreams—deals a body blow to the SF field itself.
Is there, then, intelligent life out there? Are we, impatient social animals that we are, experiencing a failure of nerve by doubting that there are other intelligences beyond our own? And if so, how might this affect SF, the most expansive and imaginative genre in both literature and film? I interviewed Dr. Seth Shostak, Senior Astronomer at the SETI Institute in Mountain View, CA, in search of answers.
DC: Dr. Shostak, thank you very much for this interview for IROSF. Tell me a little about your introduction to SF and how you came to be interested in what you do.
SS: (chuckles) My introduction to SF was via the cinema; it started out being an introduction to cinema SF and it continued that way. I've read very little SF in terms of stories or novels—I mean I've read a couple, but very close to zero: within epsilon of zero.
When I was growing up and had reached the age of ten or eleven, somewhere around there, that happened to coincide with a mini-flowering of cheesy sci-fi films in the cinema; this is when Jack Arnold was making his stuff. He was making these low-budget, black-and-white films involving giant creatures mutated by atomic weapons tests that would come out of the desert and usually destroy those who lived there—which probably improved the gene pool of the country somewhat. He also made things like The Creature From the Black Lagoon. And I went to all that stuff. I was interested in science, and I was certainly interested in films. And at the age of ten, I would go with a buddy every weekend to a movie theater in Alexandria, VA, the Reed Theater, where they would be showing the latest low-budget sci-fi flick, and I would usually vomit all night because these things really scared me! The Beast From 20,000 Fathoms, when they dropped that bathysphere into New York harbor because there's a Rhedosaurus down there, and it comes up with a frayed cable and no more bathysphere, that just made me sick all night. My Mom tried to stop me doing from this, by the way, without success. She said, "Why are you going to these films, they're only making you sick?" I said, "Mom, I've gotta go!"
But Hollywood of course realized that there was a market for these things, and they tried some expensive productions. I'm sure you're familiar with War of the Worlds; that was a very good film, it holds up even today; and I think that was made in 1954. Also Forbidden Planet, or The Day the Earth Stood Still, all those things. For a while there was a real blossoming, and that got me interested not only in sci-fi, but also in science. The fact that I studied astronomy was probably due to a film called Destination Moon, also by George Pal. I saw that at a very early age, and after that I was interested in astronomy.
DC: At the moment there's a lot of buzz about evidence of past water on Mars, the possibility of oceans and life on Europa, even perhaps of life in the cloud-tops of Venus. Certainly in the research and scientific arena, the possibility of extraterrestrial (ET) life is something that's taken quite seriously. On the other hand, in SF literature in particular, we're seeing some retrenchment of vision, with a number of authors saying they're not sure if we're ever going to have any contact with an extraterrestrial civilization (ETC); even doubting that there are such and hypothesizing that we're alone. What do you think about this countercurrent between the fiction and the reality?
SS: It's not the first time that there's been a retrenchment in the amount of optimism regarding cosmic confrères, if you will. I think you're probably aware of Percival Lowell in the 1890s. He was mapping the canals on Mars, which was a pretty good trick, given that they weren't there. He spent a long time doing this, and wrote three books about it. Everybody was convinced that Mars had not only life, but life interested in civil engineering: they were digging all these canals. [laughs] He believed that, by the way, until his death in 1916. Very few other people believed it by then. But when it became obvious to most people that the canals didn't exist, that they were optical illusions, people were disillusioned, literally and figuratively; because, doggone, all this talk about Mars, and then it turns out that Mars not only doesn't have canals, but at that point they also began to realize that the atmosphere on Mars is very thin, like one percent of Earth's atmosphere, almost no oxygen, plus it's cold on Mars: it's a cold, dry desert. That was becoming obvious in the early part of the twentieth century, and here they'd been sold this idea that there were Martians and now they're told, "Look, it's dead, Jim." And so that led to a certain retrenchment for a while, because we'd figured there was going to be not just life, but intelligent life nearby: that had been a very long-running idea, and that idea got taken out in the early part of the twentieth century.
So some people figured, okay there's still going to be life on Mars, it's just not going to be little green guys, it's going to be little green scum of some sort, it's going to be some sort of simple life. Then in 1976-77 we had the Viking landers, and they went to Mars, and they said, it's sterile, which the surface probably is; I don't think those experiments were wrong. And so again, we took a hit: this was the best hope for life beyond Earth nearby and it didn't come up roses—or pond scum, it didn't come up pond scum!
So for awhile again there was a retrenchment. And then the evidence began to build again, and we went, now wait a minute, maybe we've jumped to conclusions here: Mars clearly once had running water and now we began to think that maybe if you just dug a hole a couple of hundred feet deep on Mars you could find liquid water again. So now people are thinking, well, maybe Mars did have life, maybe it still does have life, it's just that you're not going to find it at the surface, you have to go somewhere else. So you have these cycles, and the fact that some people feel that, okay, there's no intelligence out there, to me it's a cyclical thing—I don't take that very seriously.
If you look at the long-term tendency, when I was a kid, back around the invention of the wheel, it was thought that planets were very uncommon, because the theories of how you got planets involved the close collision of two stars; that's what you heard at the Hayden Planetarium. Wasn't true, but that's what they were telling you. Then it turned out that, well, maybe planets aren't so rare. Now we know that planets are a dime a dozen; but, well, maybe life is rare. But now it turns out that actually there are a lot of habitats, and it isn't just Mars: maybe some of the moons of Jupiter; maybe Titan, the moon of Saturn; maybe even the clouds of Venus, as you pointed out. So even in our own solar system there are a lot of possibilities, and that's sort of shifted the opinion so that now I think most astronomers would say, yeah, there's probably a lot of life out there, a lot of biology; but now the argument's going to be that very little of it's going to be complex, very little's going to be intelligent; maybe none of it. But you see that the goalposts have been systematically moved, moved, moved in the direction of us not being very special.
So, yes, there are bumps in the road, and the goalposts sort of wobble back and forth—but they are moving downfield. Just look over the course of my career, if you will: we went from 'planets are rare' to now, 'well, maybe intelligence is rare'. That's a big step. So I remain optimistic: I think that intelligence is not a miracle. If you look at intelligence on Earth—there's now some research being done on this—how did we get smart? Was it some sort of accident that's just not going to happen anywhere else, or was it the kind of thing that's going to happen in a lot of places? And I think the answer's the latter. But we don't know for sure yet.
DC: It's hard to imagine evolution just doing something once, isn't it?
SS: It doesn't do that; it tends to try and find solutions that work in a lot of cases. And intelligence has survival value, there's no doubt about it. Dogs and cats are smarter than dinosaurs because they can do better by being smarter, and it's true of a lot of creatures: some birds, and for that matter octopi and so forth, are apparently pretty clever. They don't seem to play a very good game of Scrabble. . . But intelligence has been developed in a lot of species. Sentience, what we have, okay, that's only one; but that's not surprising: the first sentient species looks around and says, hey! We're the only sentient species! It's not a miracle, they're just the first ones to look around and say that.
DC: You mentioned a cyclical tendency and certainly the expectations of a culture, a society, a scientific establishment in relation to the state of current knowledge. Arthur C. Clarke wrote a great book in the 60s called Profiles of the Future, in the first two chapters of which he reminds us of instance after instance in which various eminent scientists asserted that something was impossible or couldn't be done immediately before it was, in fact, done. Do you think that a lot of the problem with this retrenchment we've been talking about is really to do with our very human lifespan and our expectations that the search for ET intelligence, the search for contact, should yield quick results? Are we impatient?
SS: I think there's certainly some component of that. People will say to me, for example, well, the first modern SETI search looking for signals—radio signals—from space was done in 1960; that's more than four decades ago, and you guys still haven't delivered here, you don't have any confirmed signals from the cosmos, and maybe that means something; because from a naïve standpoint you might think that that would mean something. If Chris Columbus had been sailing for forty-five years, you might say, Chris, you're not going to find anything. Well, that would be true in the case of Columbus, but Columbus's ship went at the same speed every day; our ship keeps getting faster. Because of the development of technology—new telescopes, new receivers, and so forth, any experiment we do today is generally more comprehensive (whatever that term embraces) than all the previous experiments put together. You're going faster and faster through these unknown seas, so the chances that you find something keep getting better and better if there's something to be found. But I do think that part of it is this naïve assumption that we're sitting here with our earphones just the way we were forty years ago, and we still haven't heard anything, so after forty years you should throw in the proverbial bath linen and give it up. That's a misunderstanding of how the experiment is done.
I think that the other factor that may contribute to this retrenchment, if it's out there—and I haven't seen it so clearly myself—in optimism about having cosmic company that's also brainy cosmic company, is the popularity of the book 'Rare Earth', and the debates that has sparked; and it's a good thing, by the way, to have that point of view out there. It says, actually, the Earth isn't just a humdrum, run-of-the-mill small planet: it's got all these special features, like a big moon, and the presence of Jupiter to clean out the inner solar system so we don't get hit by stray rocks, and we've got plate tectonics, and so on. And that if you make this big laundry list of things that are special about the Earth, you might decide that the Earth is very, very special, and we're very lucky to be here, and so on.
I don't buy into that: I think that every one of those arguments can be looked at—people have looked at them, actually—and taken apart. I don't think any of the links in this chain are very strong, I think they're all weak; and when you have a chain of weak links, it's not a very good chain. So I don't think that that's the case, but again, a lot of people have been influenced and impressed by this argument that maybe we are special, maybe this is the only place that it's happened, and the fact that you guys haven't found any signals doesn't help your case when you say that they're really out there; you keep saying that and you don't find anything. Well, that's true: but you could have talked to Chris Columbus the first couple of weeks out of Spain and said, what have you found, and he'd say, only water round the ship, and that's it. But one day that changes, and I do believe that that will happen to us. But what I believe is not the issue, it's whether we can continue to search, because if you don't search, of course you're not going to find anything.
DC: You're aware of Stephen Webb's recent book, 'Fifty Solutions to the Fermi Paradox'. What's yours?
SS: [laughs] Well, to begin with, I have to say that the whole idea that you look in your back yard and you don't see giraffes, and then you come to the conclusion that giraffes don't exist on the planet Earth . . . well, that's a big extrapolation, that's a big lever arm. [laughs again]. So I'm not sure about the logic here, because it's not even clear that you could recognize a giraffe if it were in your back yard. That's one possibility—that true intelligence, intelligence that's able to travel between the stars, is probably not little gray guys piloting saucer-shaped vehicles anyhow. I think that's very naïve, and at least anthropocentric in that case. So it could be that they're kind of around but we just don't see the evidence because we're not tuned into what we should be looking for. It's certainly happened to us occasionally in the past, and there are easy analogies: ants aren't going to recognize humans, no matter how many humans are around. So there's that.
But to me, I guess I would say that one of the explanations to the Fermi Paradox that I do like is the idea that the universe may be urbanized. And the example I've often used in talks is to say, if I were to take somebody in the audience and blindfold them, spin them around ten times, throw them in an airplane, fly them around for two days, take them to someplace twenty miles north of Las Vegas or something and then take the blindfold off, they wouldn't see much—no phone poles, no roads, no houses, nothing: just rock and desert. And they might conclude, well, it's clear that this continent is uninhabited. And that's not the right conclusion, they just happened to be in a place that was fairly barren. And it could be that this part of the Galaxy isn't terribly interesting. I mean, this is trying to suppose what true intelligence would find interesting—we don't know much about that. But if you look at where the energy is, where the matter is in the universe, it's not in this particular arm of the galaxy. This is kind of a low-grade neighborhood; maybe it's just not very interesting. The whole assumption that true intelligence would want to colonize the galaxy anyhow, that might be faulty right there. Even aside from the impediments from doing that, which are substantial, maybe it's just not on their agenda.
DC: And the counter-argument?
SS: The counter-argument. Okay, maybe they're not interested in colonizing the galaxy; and it's okay if 99 out of 100 of them are not interested, or 999 out of 1,000, or whatever. But as long as one society of intelligent beings, whatever that may be, has colonization on their brains—whatever their brains may be—then that might be enough to put them everywhere. In 1500, very few Europeans were interested in colonizing the coast of the Americas. But some Spaniards were, a few were, and that was enough to colonize the coast of the Americas within thirty years, very quickly. And that's sort of the Fermi argument, that they don't all have to be interested, most of them don't have to be interested, but if a few are, they can do it quickly. And consequently we should see them; we should see some evidence that they've done that.
DC: Aside from broadcasting, would you expect that they'd send robotic probes, rather than visit in person?
SS: Well, again, this is speculating on alien sociology, for which the data are sparse [laughs]. There may be alien probes; I doubt that they'd be biological, the really sophisticated ones. But there's not a lot of advantage to having probes, really. From a distance of—well, any distance, really, certainly hundreds of thousands of light-years—you could learn that Earth had biology, even if you were looking at Earth the way it was in the time of the dinosaurs or the trilobites. You could see oxygen in the atmosphere, you could see some methane in the atmosphere; you'd see some indications that there's biology on Earth. You'd say, hey, well, Zork! Here's another planet that has biology; maybe we ought to send a probe and hang out. But it might be a billion years before humans arrive, and so now this probe has got to hang out there for a billion years, maintaining itself. Meanwhile the home planet has gone bust or whatever. And even if finally the probe wakes up and says, oh, there's intelligence down there, well, you could essentially have learned that just as quickly by waiting for the TV shows to get to you, right? I mean, the probe doesn't give you a whole lot of advantage in terms of learning about something: the advantage a probe gives you is that it could send you better pictures. It's nearby, so there's some advantage, but maybe you only send probes to planets where you have evidence of something that's really interesting to you, and biology might not be good enough. It might be for us, because we haven't found it, but if there's enough of it around, you think, oh, man, just put it on the list. . . another planet with biology, okay, so what? But if you're starting to get I Love Lucy, you might say, okay, now they've got thinking beings, they've got culture; now we'll send a probe. But those signals haven't gone out far enough yet to really reach anybody: they've only reached the nearest couple of thousand stars at most, and that's probably not a big enough number to alert anybody who's out there. They just don't know we're here yet, so I don't think their probes are going to be here.
DC: You mentioned anthropomorphism. The popular mass-culture perception of the alien is not very different from that of the angel. It's an image based on a mass-produced, almost superstitious, icon, rather than a scientific model. How do you address that in your public outreach?
SS: Actually, the subject seldom comes up, to be honest [laughs]. Very infrequently will people say, okay, we understand how the telescope works, and your observing strategies and everything, but what are the aliens like? What are they going to look like, will they really be little gray guys with big almond eyes or whatever, who don't bother to ever get dressed in the morning. . . it doesn't come up very often. But I have thought about it and I do occasionally put it in the talks even when they don't ask for it, because I do think it's an interesting thing. What I do is I take cinema aliens, sci-fi aliens, and I just throw them up on the screen, and a lot of them are actually good examples of bad engineering, if you will. Remember in Starship Troopers, they have these giant bugs, the idea being that people don't like bugs much, and if you have big bugs maybe they'll like them even less; so the aliens are giant bugs, and they're really bad aliens. But they're also badly engineered, because if you take a bug and scale it up a hundred times or a thousand times, it won't work—the exoskeleton can't support it, it can't breathe. . . So I'll sometimes talk about things that don't work.
The other thing I'll talk about is the fact that eight out of ten movie aliens—even today, when with computer animation this is no longer necessary—look like. . . us! They always look like us. ET really looked like us! [laughs] And that's of course a requisite for Hollywood, because if the aliens are unrecognizable then you can't identify them, you can't read them, you don't know what they're likely to do; they can't be scary because you just don't know how to read their faces, if they have faces. So Hollywood is kind of caught there, they have to make them anthropomorphic in a way, at least a lot of them. But you can point out how closely they resemble us, and then just compare them with any five critters you identify by throwing darts at a map of the zoo: you might get a fish, an alligator, a coyote. . . and they don't look like us, yet they share the same planet. So I point that out, that the aliens probably aren't going to be much like us. And that sometimes resonates with people. They realize that what they've been seeing on The X-Files, or the little, smooth gray guys with no hair problems and so forth, that that's all a little unrealistic.
And sometimes I'll go beyond that and say that anything that we're likely to hear on the radio (telescope) is probably very advanced: they will be easier to find that the ones that aren't so advanced. And if they're very advanced, if they're even only a hundred years beyond us, they probably won't be biological anymore; because we probably will invent machine intelligence, if there is such a thing, and we'll probably do it this century. And I do firmly believe that you can do that, because if that's not true, then there's a miracle going on in our skulls. Nobody assumes there's a miracle going on in their gallbladders, but they like to think that there's a miracle going on in their skulls. But if there's not, then you can have machine intelligence; and once you've invented that, it evolves very quickly. So I suspect that the whole idea of these little biological entities walking around, a whole bunch of guys that look alike and want to perform experiments on you involving your privates. . . that speaks to our own fears, but it probably has very little to do with what real aliens would be like.
DC: Let's assume a best-case scenario. In a short span of years, SETI receives a signal, whereupon of course the question becomes, is it intelligible or not? If we receive an intelligible signal—which essentially says "Hello, we're out here, is there anyone else out there?" and it comes from, say, within twenty to fifty light-years, so a response within a human lifetime is possible—what's the protocol?
SS: Well, there's no protocol for that scenario entirely; there's a protocol that deals with what happens if you find a signal, irrespective of how far away it is. What you're supposed to do is verify it, tell all the astronomers in the world so they can all point their telescopes at it, and then inform the public, and the government, and everybody else. Of course, it won't work quite that way. In my experience, what happens is that the media will deal with it first, and it'll be all over the media when we haven't even confirmed it yet. You can be sure of that. You'll read about it in the papers long before we're absolutely sure that it's what they're saying it is.
But let's take your scenario. Okay, it turns out that the signal's coming from a nearby star—which by the way, I think is unlikely, not just because we've looked at all the nearby stars; that per se doesn't mean they're not there, maybe we were looking when they were out to lunch, there are a lot of ways you can miss a signal. But the stars within 150 light-years, we have looked at. So I think it's unlikely that they're so nearby. And also on the basis of statistics I don't think it's likely that they would be that nearby. I think it's more likely that they'll be 500-1,000 light-years away, the nearest ones. That's a long way, and would make for a tedious conversation. But let's take your scenario, that they're close enough that you could have some sort of conversation over decades of time. Right: what do we do? Well, there is no protocol, although there's a proposed protocol which suggests that no reply should be sent from Earth without international consensus. That means the United Nations would get in on it and it might take twenty years to decide; but maybe that doesn't matter if these guys are sixty light-years away—what's another twenty years?
DC: The Department of Homeland Security will be all over it.
SS [laughs] It doesn't matter! It just doesn't matter. Our reply's already out there in the form of military radars—which make very nice, strong signals—television, of course, FM radio, other high-frequency signals; those things are out there, fifty light-years already; they got a big head start, so it doesn't matter what you say now. And it probably doesn't matter what you say to the aliens either, because how are they going to know that this is the real signal? You could direct it toward them, make it much stronger for them, and tell them, look, this is what we have decided to say to you; but to me that's like the Indians of 1492 standing around on the island as Columbus walks ashore, saying, okay we've got a protocol about how we're going to handle this, and you, Big Feather, you're going to talk to Columbus, and that's all, and you just tell him the following things. Well, Columbus doesn't understand it to begin with, and he gets kind of bored with Big Feather after about ten minutes, and wants to talk to somebody else. I don't think it matters.
If it were up to me, we would send them the Internet. Send it all. I'm going to give a talk about that, actually, later in the summer. None of this, we'll have a plaque, and we'll show them a man and a woman, and we'll show this, and we'll show that, and we'll tell them about our culture, and we'll tell them about our languages, and we'll tell them about all this stuff ... just send them the Internet. Just send them everything. That way they can figure it out. They can decipher our language if they have a lot of redundant information. And then they can build their own browser. Or send them a browser if you want; but they don't know about our computer technologies, so you just send them all this info, all the bits, and let them build their own browser. They know how to do that [laughs]. And then they can learn all they want by just browsing the web, as it were.
DC: That's an excellent idea. So you're not afraid of the 'shouting in the jungle' scenario—that they might be evil, and they're going to come and get us?
SS: Well, there is that. I think it's unlikely, but because the consequences would be so dire, even if you thought there was a tiny, tiny chance that might happen, you might want to take issue with sending them stuff. There are people who do worry about that. The Astronomer Royal of Britain was very unhappy about that at one point. But if you're really worried about that, then let's shut down the BBC tomorrow, let's turn off all the radars, let's turn off all the TV stations, because they are doing exactly that. If you're worried about that, it's too late: build your shelter now.
DC: If we do make contact, what do you think will be the effect on the culture of science fiction? Will that be the end of the genre, or do we just get a whole new bunch of material to work with?
SS: Well... I can hardly imagine it's the end of science fiction. The little I know about science fiction doesn't seem to suggest that. Since we found out that there probably aren't any Martians, there's been a whole lot of science fiction about Martians. Even when I was a kid there were still Martians running around. War of the Worlds was a great film, because even in 1954 people still thought, well, there might be Martians, and they might slam into rural America tomorrow afternoon. Hungry [laughs]. Or at least malevolent. They come here for our water—and, remember? They get taken out by our bacteria. And the ironic thing is that if there are Martians—they are bacteria.
But when we found out that Mars doesn't look so good for Martians—and there might be something there, but it's not going to be sentient beings, it's not going to be guys building spaceships and death ray weapons—did that stop science fiction? Heck no, the aliens just moved out! And science fiction didn't get any worse, I'm sure it got better. So if we find aliens. . . well, now you don't know much, because keep in mind, if we succeed next week, what are you going to know? All you're going to know is that there are all these bits coming, this signal, and it's from this star, and this star is 872 light-years away, and it's this kind of star; and you'd know a few things, like the orbital period of the planet, and maybe the length of their day. . . you'd know a few astronomical things. You would know nothing of their culture, or what they're like. Nothing. And you might never know that, because if these guys aren't deliberately trying to make it easy for you to understand that signal, you're never going to get it. It'd be like giving a modern TV signal to Neanderthals: they will never, ever, ever, get it. And that may be our situation: we may never get it, but you know there's something there, and you see all these bits coming in, but nobody ever figures them out. Are the sci-fi writers going to say, well, time to get another day job? Heck, no! They're going to tell you everything about that society, because you don't know, and you may never know. And now you know they're out there, and now you can hypothesize: they've got their own Empire, and they've already sent the rockets our way to make sure that we get snuffed out so that we don't become a threat. . . No, It's not the end of sci-fi. I can't believe it!
DC: And if we find one, then the wall is down, isn't it? If we find one, there are others.
SS: Yes. If you find one hippo, there are probably lots of hippos [laughs].
DC: That's very encouraging.
SS: Yes, that's true. That's the assumption, and that's always been the case in astronomy: you find one quasar, there are endless numbers of quasars.
DC: Do you see it in our lifetime?
SS: I do. I certainly see it in the next couple of decades. I do, because of this new telescope, the Allen Telescope Array, which has so much more capability for searching quickly through lots and lots and lots of star systems. I just did a little computation that by the year 2025 it will have looked at so many stars—millions!—that the chances are that if even the more conservative estimates of how many civilizations might be out there are the right ones, you still would trip across one by the year 2025. Now that may turn out to be wrong, but that's just using the numbers that we take as reasonable in the SETI community. But of course, the SETI community assumes that they're out there, and not everybody agrees with that.
DC: Let's hope they are. Dr. Shostak, thank you very much.