Seth Shostak: Why Should We Search For ET? Will we find ET in the next 25 years? Seth Shostak, senior astronomer at SETI, says yes. He explains that new technologies and the laws of probability make the breakthrough likely.

Why Should We Search For ET?

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript


It's the TED Radio Hour from NPR. I'm Guy Raz. So one night in 1968 Seth Shostak was searching for stars.

SETH SHOSTAK: At a radio observatory behind the Sierra Nevada mountains in California, here in California.

RAZ: Seth was gathering data for his Ph.D. in astrophysics.

SHOSTAK: In those days, the radio observatory - the staff - went home at 5 o'clock and so I was here at 3 in the morning. And it's dark outside and you can hear the coyotes and, you know, it's a very tedious thing, you're just mostly sitting there occasionally punching a button.

RAZ: And that night, he happened to be reading a book by a Russian astronomer named Iosif Shklovsky who had a theory for interstellar communication.

SHOSTAK: And it kind of dawned on me that the very instruments that I was using for my research work, which was to study galaxies in fact, could also be used to pick up signals from extraterrestrial beings.

RAZ: So that became his goal, not just to search for galaxies, but to find life among them. And almost 30 years later - this is in 1997 - that search was about to come to an end. Seth was eating dinner with his family at home when the phone rang, and on the line was his boss.

SHOSTAK: And he said Seth, I think you ought to come over to the institute because we've got a signal going on and it looks pretty good.

RAZ: The institute is a place called SETI, it stands for search for extraterrestrial intelligence. It's based in Mountain View, California. And the researchers there monitor signals from outer space, hoping that one of them might be a message. And the way they describe the process is like when you're driving late at night, far away from a city and you're trying to find something on the radio. And most of the time, you're just tuning through static.


RAZ: But suddenly...


PETE SEEGER: (Singing) Star light, star bright. First star I see tonight.

RAZ: ...A signal pops through and you know something is out there. And that's what happened at SETI that night in 1997.

SHOSTAK: So I came here and I found, you know, half a dozen of the employees here seated around computer monitors all watching this signal that looked like the real deal.

RAZ: It seemed more promising than anything they'd ever heard - the possibility of alien life reaching out across the cosmos. And all night the signals kept coming in.

SHOSTAK: You know, this went on and on, and it still looked good. We'd do various tests and it still looked good, and we did more tests and it was still looking good.

RAZ: Your adrenaline must've been racing.

SHOSTAK: What I did feel was very nervous because I thought, you know, this is going to wreck up my whole week. I've got dinners planned and, you know, meetings and so forth, and now suddenly we found E.T.

RAZ: You guys were like, about to change history. What happened?

SHOSTAK: Well, we found out that it was interference. Actually, we had tracked it down. It was due to a satellite around the earth that happened to be - its signal was bouncing around the steelwork of our antennae in just the right way.

RAZ: You must've been so disappointed.

SHOSTAK: Well, of course. When it turned out that it was only interference, then this other feeling came over me - that darn it, you know, too bad, just too bad. But we'll keep going.

RAZ: What's it like to search for something that you might never find that might not even exist? Today on the show, "In Search Of." Looking for that elusive thing, from aliens, to love, to mythical sea monsters. And ideas about why the search is almost always more important than what you find.

So why the search? Here's Seth Shostak's explanation from the TED stage.


SHOSTAK: Now, a lot of people think that this is kind of idealistic, ridiculous, maybe even hopeless. But I just want to talk to you a little bit about why I think that the job I have is actually a privilege, OK, and give you a little bit of the motivation for my getting into this line of work, if that's what you call it. Now, we still haven't heard anything. In fact, we don't know about any life beyond Earth, but, I'm going to suggest you that that's going to change rather soon. And the part of the reason, in fact, the majority of the reason, why I think that's going to change is that the equipment's getting better. So this means that over the course of the next two dozen years, we'll be able to look at a million star systems. A million star systems looking for signals that would prove somebody's out there. Recent results suggest that virtually every star has planets, and more than one. They're like, you know, kittens.

You know, you get a litter. You don't get one kitten, you get a bunch. OK. That's a lot of real estate, but of course, most of these planets are going to be kind of worthless, like, you know, Mercury or Neptune. Neptune's probably not very big in your life. OK. So the question is what fraction of these planets are actually suitable for life? The smart money is suggesting that the fraction of planets that might be suitable for life is maybe 1 in 1,000, 1 in 100, something like that. Well, even taking the pessimistic estimate that it's 1 in 1,000, that means that there are at least a billion cousins of the earth just in our own galaxy.

RAZ: Statistically, it's actually probably impossible that we are alone, right? Just if you just think about the number of planets in our own galaxy, like, at least a hundred-billion or more.

SHOSTAK: That's correct. That's an argument based on large numbers, of course. And you can't say 100 percent that it's impossible. It's not impossible. It's just highly improbable because that would make us very, very special. That would make what's happened here on the earth a miracle. And you know, a lot of people like to believe in miracles, but if, you know, you look at the history of humanity or certainly the history of astronomy - you know, Aristotle thought the earth was the center of everything - every time we thought we were special, we were wrong. I think that it's a lot safer bet to assume that we're not a miracle than that we are.

RAZ: Yeah. How convinced are you that we're going to know in the next few decades?

SHOSTAK: Well, I bet people cups of coffee on that. So Guy, if you want a cup of coffee...

RAZ: Yeah.

SHOSTAK: ... (Laughter). Within a couple of decades I think we will find life in space. And I think unless life is very rare or very hard to detect, we will succeed relatively soon.


SHOSTAK: Now, let me tell you about some aspect of this that people don't think about, and that is - what happens? Suppose, you know, that what I say is true. I mean, who knows, but suppose it happens? Suppose some time in the next few dozen years we pick up a faint line that tells us we have some cosmic company. What is the effect? What's the consequence?

And the answer absolutely is we don't know the answer. We don't know what that's going to do, not in the long term, and not even very much in the short term. I mean, that would be a bit like asking Chris Columbus in 1491, hey Chris, you know, what happens if it turns out that there's a continent between here and Japan where you're sailing to? What will be the consequences for humanity if that turns out to be the case?

I mean, Chris would probably offer you some answer that you might not have understood, but it probably wouldn't have been right. And I think that to predict what finding E.T. is going to mean, we can't predict that either. But here are a couple things that I can say. To begin with, it's going to be a society that's way in advance of our own. You're not going to hear from alien Neanderthals, they're not building transmitters. They're going to be ahead of us. Maybe by a few thousand years, maybe by a few million years. But substantially ahead of us. And that means, if you can understand anything that they're going to say, then you might be able to short-circuit history by getting information from a society that's way beyond our own.

Now, you might find that a bit hyperbolic. And maybe it is, but nonetheless it's conceivable that this will happen. And, you know, you could consider this, like, I don't know giving Julius Caesar English lessons and the key to the Library of Congress. It would change his day.

RAZ: What is it about you that pushes you to keep looking? Like, to keep searching for something that most people would never devote their lives to?

SHOSTAK: Well, first off, it's very interesting. It's curiosity. A lot of it is curiosity. People who are not scientists don't always understand why scientists will beaver away on some fairly arcane question for an entire career, not appreciating that they're doing it simply because they're curious, they want to be the first to know something about nature. This a little bit unlike many jobs in the sense that you're dealing with a very big-picture question. There's no guarantee you're going to succeed, but if you do, it's really interesting and potentially very important.

RAZ: I mean, is the search just as important as the goal?

SHOSTAK: In some sense I think that it is. I think just doing the search is important. I tend to liken this to the existence of Terra Australis, the continent that was hypothesized to exist at the bottom of the globe, what we call Antarctica now. Because for a long time, up until the 1800s, nobody really had seen the place. They just thought, well, it's kind of reasonable there might be something there, but then again maybe not. And you could just drink a whole lot of beer and talk about in the bars till early in the morning, and that would never answer the question. To answer that question you have to do the experiment. Somebody has to build some ships, fund them, send them down there and take a look. And that's sort of where we are with SETI. You know, you can argue they're likely to be there, they're not likely to be there. But in the end, doing the experiment is the important thing.


SHOSTAK: SETI, I think, is important because it's exploration. And it's not only exploration, it's comprehensible exploration. Now, I got to tell you, you know, I'm always reading books about explorers. I find exploration very interesting. Arctic exploration, you know, people like Magellan, Amundsen, Shackleton, you see Franklin down there, Scott - all these guys. It's really nifty, exploration. And they're just doing it because they want to explore. And you might say, oh, that's kind of a frivolous opportunity. But that's not frivolous, it's not a frivolous activity because I mean, think of ants. You know, most ants are programmed to follow one another along in a long line. But there are a couple of ants, maybe 1 percent of those ants, that are what they call pioneer ants. And they're the ones that wander off, they're the ones you find on the kitchen countertop - you've got to get them with your thumb before they find the sugar or something. OK. But those ants - even though most of them get wiped out - those ants are the ones that are essential to the survival of the hive. So exploration is important.

RAZ: What if you never find that thing that you're searching for?

SHOSTAK: Well, that's sort of an interesting question because the fact that you didn't find it, does that mean anything? Is that significant in some sense? And the answer to that is probably it's not. Because you can never prove that they're not out there. I mean, who hasn't stood outside at night, looked up at the stars and wondered, you know, do you think there's anybody up there that's looking up back this way? I'm sure cavemen would've asked that question. I don't think that's a new question. I think we're kind of hardwired to be interested in other creatures that are at least as clever as we are because aliens, they represent the tribe on the other side of the hill.

RAZ: Seth Shostak is an astronomer at SETI. He's also the author of "Confessions Of An Alien Hunter." Watch his full talk at

Just promise me one thing.


RAZ: If they do land on Earth, can you please promise me you will at least take them to In-N-Out Burger?

SHOSTAK: (Laughter). There's one right nearby.

RAZ: Coming up on the show, writer and comedian John Hodgman is here.

JOHN HODGMAN: Yes, I have not been taken away by aliens. That would be a fun ending to this radio appearance.

RAZ: Don Hodgman's own story of searching for life from another world, that's coming up later. And while you're waiting, if you don't subscribe to our podcast, it's really easy. Go to iTunes, search for TED Radio Hour and click subscribe. I'm Guy Raz and you're listening to the TED Radio Hour from NPR.

Copyright © 2015 NPR. All rights reserved. Visit our website terms of use and permissions pages at for further information.

NPR transcripts are created on a rush deadline by Verb8tm, Inc., an NPR contractor, and produced using a proprietary transcription process developed with NPR. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.