The Big Idea: Seth Shostak

Science fiction writers such as myself live in a state of wariness about the concept of alien intelligence truly existing. On one hand, how cool would it be to finally know we’re not alone in the universe — every science fiction writer in the world would be vindicated. On the other hand, we’d also be out of a job, or at least have to change our job title, and “science fact writer” already means something else.

Seth Shostak, for example, qualifies as a “science fact writer,” even though he’s writing about aliens in his new book Confessions of an Alien Hunter. That’s because Shostak is in fact the Senior Astronomer for the SETI Institute, which devotes its time and efforts to searching the skies for evidence of extraterrestrial life. His book, which has garnered great reviews (“compelling and thought-provoking” — Washington Post) talks about that task, separating the fact and the fiction and presenting a state of the search. Yes, this guy is trying to put me out of a job. But I’m not holding it against him.

And what is the state of the search? Here’s Shostak to give you a brief overview.


In my heart of hearts, it just seemed reasonable that the public would want the low-down on aliens.

Not the Fox TV low-down.  Not the conspiracy-blog low-down.  Not the new-agey I-can-see-their-auras low-down.

No, I figured the great unwashed, as well as their better-bathed brethren, deserved to hear the tweed-jacketed, gray-haired academic low-down.  Call me deluded.

Of course I have a canine in this fight.  After all, I am one of those tweedy, barely hirsute academics.  And my day job is to participate in the Search for Extraterrestrial Intelligence, or SETI.  So writing about the hunt for cosmic company is tantamount to penning an extended job description for myself.

But personal involvement aside, there’s no doubt that the subject of extraterrestrial life plays well at dinner parties. That’s because space aliens have invaded our literature, our cinemas, our televisions and – according to many – our airspace. Aliens are the modern equivalent of centaurs and Cyclopes.  But they’re actually better than those fabled fauna, because you can’t prove they don’t exist, and you might prove they do.

Indeed, astronomers, paleontologists and biologists have – in the last two decades – provided a lot of backhanded support for the idea that worlds with life are about as plentiful as mosquitoes in Minnesota. To cite an obvious example, note that a dozen years ago we didn’t know whether planets were commonplace or rare.  Now you can safely wager that there are a trillion or more planets in our home galaxy.  (For the unaware, note that there are a hundred billion other galaxies.)  That’s a lot of real estate, and while much of it might be fiery, fumy, or frozen, some worlds – simply by chance – will have conditions that could provoke the emergence of life.

Another relevant science tidbit is the fact that living things have glazed the Earth for almost the entire history of our planet. It doesn’t sound as if getting life started was a tough project. Rather than being some sort of improbable happenstance, life may be an irresistible chemical phenomenon that festers on any world boasting liquid water.

These facts don’t prove that the hidden recesses of the night sky are filled with thinking creatures.  But the possible niches for life are stupefyingly plentiful. So when I talk to the public about our search for aliens, I’m always intrigued by the handful of audience members who, despite my presentation, prefer to think we’re alone.  These people are special, because they believe in miracles. In a cosmos that is achingly vast, in which stars and planets are strewn like snowflakes in the arctic, they contend that only our world has organisms able to know things, to comprehend their environment and to chart their destiny. What a pitifully impoverished creation that would be.

Such a barren cosmos sounds unreasonable, not to mention lonely.  Nonetheless, the convictions of science aren’t based on what seems reasonable, but on what we observe. Learned people can argue the possibility of space aliens until the heifers come home, but in the end, the debate will only be settled if these beings are found. And that’s what SETI is all about – picking up radio waves or laser flashes from other worlds. Either type of signal would divulge the presence of technological intelligence.

SETI is not big science; it isn’t the Large Hadron Collider. It’s a back-burner experiment involving – world-wide – fewer people than work in a pit crew.  It’s funded, at least in the United States, by private donations. Given the limitations of budget and manpower, it’s hardly surprising that – so far – we haven’t found proof of cosmic company.  But if the effort can be sustained for another two decades or so, improvements in technology will allow SETI researchers to examine millions of star systems.  To my mind, that’s the type of effort that could lead to success.

Much of my book explains how SETI stalks its prey – the nuts and bolts of the strategies used to scan the sky.  There’s also a lot of history, both institutional and personal.  But I was keen to do more than merely gratify the interests of propeller heads, because – as noted – aliens are appealing (or unappealing, depending on their demeanor and intentions) to nearly everyone.

This popularity results in phone calls and e-mails every week from people who want to share their ideas about E.T. Sometimes these communicants offer technical advice: why don’t we look for gravity waves or neutrino communications?  What about searching for signals sent our way using hyperdimensional physics (whatever that is)?

But for much of the public, such technical details are less interesting than SETI’s sociology.  Three questions routinely dominate my correspondence: (1) what happens if you find a signal, (2) are aliens visiting Earth, and (3) will E.T. be similar to us in appearance and construction?

These are matters of immediate and personal concern.  If I talk about the algorithms used to sift through cosmic static, many people’s eyelids lower to half-mast. But when I assure the public that the government won’t hide information about aliens – that everyone will hear the news right away – their ears perk up like a starched bunny. Both SETI policy and practice ensure that any interesting signal will show up in your favorite blog within days.

What about UFOs?  Half the populace is convinced that the aliens are already here, flitting above the landscape in their saucer-shaped craft, and amusing themselves by hauling people out of their homes for some non-consensual experiments. Well, the evidence for this is as flabby as a sumo wrestler gone to seed.  Consider the famous Roswell incident of 1947. Should we believe that aliens trundled hundreds of light-years to Earth, and then botched the landing?  If you look carefully at the facts, the claim that extraterrestrial craft cart wheeled into the New Mexico desert is no more credible than the assertion that leprechauns are camped out in the forests of Ireland.

Then there’s the matter of what the aliens will look like.  Will they be similar to us, creatures built of squishy protoplasm, and having some alien variant of DNA?  That’s possible, but I think there’s good reason to expect that any aliens we discover will be highly evolved artificial intelligence.  That’s right: machines.  This despite the fact that everyone seems to expect little gray guys, sporting big eyes and flat personalities.

My big idea is to explore what I believe is a big fact – that a remarkable occurrence could take place well within your lifetime: the discovery of thinking entities far beyond our solar system.  As our knowledge of astronomy grows, this idea seems less and less fanciful: no longer merely an intriguing construct of fiction, but a plausible possibility. The technology of the 21st century could provide the proof.  Proof that the biology on this planet is not something miraculous. Proof that we have company.

Since its beginnings, terrestrial life has lived alone, cloistered and unaware.  In “Confessions of an Alien Hunter,” I explain why four billion years of isolation may soon come to an end.


Confessions of an Alien Hunter: Amazon | Barnes & Noble | Powell’s

Watch Shostak discuss his book on the Colbert Report. Read his recent New York Times op-ed. Follow him on Twitter. Listen to his podcast, Are We Alone?

26 thoughts on “The Big Idea: Seth Shostak

  1. I dunno; just because aliens suddenly become “real”, doesn’t mean SF writers would lose their schtick; they’d just be writers writing more fictionally about something that’s more science-y, a la Ben Bova’s Kinsman series.

  2. Wow, Seth Shostak! I’ve *met* him! He’s awesome. I introduced him to a youth science audience, and he introduced himself to me with “Hi Nightsky, I’m your long-lost uncle that you’ve never met.”

  3. Discussing the possibility of life on other worlds, sentient or otherwise, always puts me in mind of Pterry Pratchett’s line, “Life exists where it can. Where it can’t, it takes a little longer.”

    As well as those videos of whole ecosystems existing on the ocean floor in areas where there is no light and in some cases, little heat.

  4. And of course what we all really want to know is, what does Shostak think of The X-Files?

    More seriously, I wonder about those audience members. I tend to fall on the ‘probably alone’ side, not because we’re special, but as a sort of flinchy reaction to the Grey-huggers. I’m guessing that Shostak is alluding to people who are angry at the idea that God did not make us individual and special, and see his work as a rebuke to Genesis.

    Will definitely be picking up a copy of this.

  5. It’s amazing how many book titles go straight from “The Big Idea” to my (online retailer) wish list. Just wanted to let you know it’s appreciated.

  6. So many books, so little time! Why can’t someone just pay me to stay at home and read?

    This sounds like a fascinating book – and totally accessible, if it’s anything like the writeup above.

  7. It is either funny or sad that though I am a professor of Physics, my very first thought was, “Oh, he has Jodie Foster’s job In Real Life.” Maybe it just says that I watch too many movies.

    Then of course he has Drake doing his intro, too! As a kid I learned about the Drake Equation via Gene Roddenberry. Yeah, I watch too much TV, too.

    Dr. Phil

  8. So when I talk to the public about our search for aliens, I’m always intrigued by the handful of audience members who, despite my presentation, prefer to think we’re alone. These people are special, because they believe in miracles.

    I’m not sure how to take this. Do I prefer to think we’re alone? No, hell no, a hundred times hell no. I’d prefer to think there’s life not only where there’s water but even in surprising places where there isn’t but the conditions are nonetheless ripe for complicated chemistry to organize into increasingly complex forms in reaction to selective pressures in the environment. And, better yet, I’d like to think that some of it will not only be intelligent, but will also be social and willing and able to spray the universe with coded electromagnetic radiation (however intelligent dolphins may or may not be, an extraterrestrial marine creature will probably never build radios to talk to the universe with, it just isn’t physically convenient; at another extreme, one can imagine an advanced species abandoning radio waves in favor of something esoteric–perhaps some sort of quantum-entanglement-based communications device–and thus be undetectable and silent to us).

    But wanting it doesn’t make it so. We fill in variables in the Drake Equation with better and better information as our educated guesses slowly become observed facts (e.g. the number of extrasolar planets becomes an increasingly real number every year), but the Fermi Paradox still vexes: if the galaxy is full of smart ETs, where are they?

    One answer, unfortunately, is that “alone” may be a sort of relative term. The “hundred billion other galaxies” really means nothing for conversation purposes, since any hope of communication across those vast voids truly is improbable SF at this point; indeed, at the present time we’re only detectable within a few dozen light years–detecting a signal from the other side of the galaxy would ultimately and tragically be a profound, awesome, and meaningless thing: we’re not alone, but we might as well be if the only signal we get is from a planet that’s been long-dead by the time we hear from its inhabitants. That’s not entirely meant to be discouraging; such a signal would be inspiring, astonishing–but it would also be heartbreaking.

    And then there’s this: while I don’t believe in miracles, I do believe in improbabilities. I hope advanced, intelligent life is as common as water, but it may well prove to be as rare as water-rich dual-planet systems orbiting in a stellar “comfort zone” sheltered from cometary bombardment by a perfectly-placed gas giant’s gravity well. We may well be forced to realize that our position in the universe is literally unique, that it’s a fortunate result of chance.

    I hope not. From the bottom of my heart, good luck, Dr. Shostak.

  9. “If you look carefully at the facts, the claim that extraterrestrial craft cart wheeled into the New Mexico desert is no more credible than the assertion that leprechauns are camped out in the forests of Ireland.”

    Leprechaun-denier!! :)

    @eric – I don’t think you’ve really thought through the numbers involved. Assuming there are a trillion planets of all kinds in the galaxy you’d have to insert vanishingly small numbers everywhere to end up with us as the only intelligent life in the galaxy. To the point about true uniqueness in the universe, I just don’t think humans really comprehend how big 100 billion times 1 trillion is. No, those other galaxies don’t matter in a practical sense, but as the argument on whether we’re unique in the entire universe, they certainly do.

    The reason I think we’re unlikely to find scads of aliens to chat with has more to do with time. What are the odds that other intelligent life is at or close to our particular stage of development? We’re like a child who’s just toddling around – 500 years ago we JUST really started down the path we’re on. 5000 years ago we were starting to build cities. 5000 years from now? I don’t think we can imagine. And those times are infinitesimal on cosmic scales – expand that another 10x and think of how we could communicate with out 50,000 year ago ancestors… or our distant descendants. I don’t doubt that there is other intelligent life out there… I wonder how much of it is close enough in developmental terms to be comprehensible. If only there were a book that talked about this….

  10. We’re unlikely to be alone in the sense of “there’s no other intelligent life in the universe.”

    We are very likely to be alone in the sense of “we’ll never make meaningful contact with any other intelligent life.”

    We’re way out on the skinny edge of the galaxy. Even if there are intelligent civilizations out there, why would they bother with us? That’s why I don’t believe that aliens will visit us either to subjugate/slaughter/eat us or to enlighten us and bring us into the Galactic Community.

    Beings 100,000 lightyears from us won’t hear our first radio signals for about 99,900 years. And any that we pick up from them will be 100,000 years old. For what period does a civilization use radio? Our SETI window has to be exactly the (distance in lightyears) number of years after a period IN THAT WINDOW to pick anything up from them at all.

    I think probably we’ll pick up something eventually. We’ll be able to identify it as patterned, but not to decipher it; in other words, it’ll be a missed call from a blocked number, not a real communication. And then we’ll know, not that we’re not alone, but that we weren’t alone DIL years ago.

    That’s still alone.

  11. Rick: well, yes you would. And right now some of those numbers are reasonably good guesses and others are unknown. Too, it’s possible that the survival of life long enough to achieve technological intelligence depends on some unlikely events–there are scenarios in which evolution on Earth is linked to qualities resulting from our peculiar moon (“That’s no moon,” one might say–it’s practically a captive plutoid) or from Jupiter’s happy location in a place to deflect/absorb a good bit of the debris from the solar system’s formation away from the inner planets. Gas giants may be common, but many of the ones we’ve detected have been very, very close to their stars, f’r’instance; similarly, double planets may prove to be common, but water-rich double planets in stellar comfort zones? Maybe, maybe not: the point is that it actually isn’t hard to find ways to make our continued existence a statistical outlier, an anomaly, even with trillions of planets and even with the hypothesis that life arises frequently (it may be just as routinely thwarted by debris impacts, or never gets much past the pool-scum stage).

    Mind you, I’d be happy to be wrong. In fact, one reason I think exploration of our own solar system is important is that finding something alive (or formerly alive), however small or fossilized, on Titan, Europa or even Mars (or inside a comet, or on an asteroid, or anywhere unlike Earth we can get to) would help us thumb our noses at some of the undeniably improbable things about our planet when evaluating the probability of intelligent life elsewhere. (I.e. it would suggest the existence of life is less special than it seems to be, which would actually be a welcome discovery.)

    Heck, “wrong” may even be a bad way to put it–I don’t tender it so much as an article of personal faith or conviction, but just because it’s a likely possibility based on the currently-available facts. I mean, there are also non-unique/common things you can point out about our situation, some of which have already been mentioned, like the high occurrence of planetary systems of one sort or another.

    One other point: the Copernican Principle suggests we’re in the middle somewhere, temporarily and otherwise, but we don’t have any firm basis for knowing how average we really are. Indeed, at the moment our sample size of intelligent technological species is exactly one, making us the most advanced and least advanced race in the whole universe according to the current rankings. I understand where you’re coming from with the +/-50k years observation, in other words, but the fact is we just don’t know; this doesn’t change what you’re saying, in a way, since even if we’re the most advanced civilization in the universe your comments about relating to our descendants would still apply, but I thought I’d point it out.

    It’s worth mentioning in that context, as kind of an aside, that there are other variable than the frequency of planets or likelihood of life developing that tie into that. It’s possible, for instance, that we’re simultaneously relatively advanced and relatively young: some versions of the Drake Equation have added variables for species survival–it’s possible, for example, that intelligent civilizations arrise quite frequently and just as frequently destroy themselves with weapons of mass destruction or self-inflicted environmental catastrophe before they get a chance to discover whether or not they’re alone or to be heard by any of their neighbors.

    Not quite on point, necessarily, but something sobering to think about.

  12. Eric 14: the Copernican Principle suggests we’re in the middle somewhere, temporarily and otherwise

    Did you mean ‘temporally’ here? Because otherwise I don’t understand that sentence.

  13. I think Xopher @13 makes some very compelling points. I imagine Seth Shostak has considered them already and wonder what his reaction to them is in the book or otherwise.

  14. Just wanted to say how much I love The Big Idea. I haven’t bothered reading any Science Fiction books in a long time, so this column is a godsend to me. Granted, because I’m living in Australia these books are sometimes hard to find, but always worth the read. Thanks for another great recommendation!

  15. Xopher: no, I meant that the Copernican Principle is often construed to mean that we’re somewhere in the middle in terms of technological or cultural development, as well as where we happen to be biologically or how our planet stands compared to other life-sustaining planets or where Sol is stellar-evolution-wise–but you’re right that I phrased that pretty poorly.

    The problem is that while the Copernican Principle is a useful way of giving ourselves a kick in the pants and enforcing modesty, it also has no objective basis. That is, we should continue to remind ourselves we probably aren’t special, in spite of the fact that we are (as far as we know) unique and therefore very special.

    It’s often taken for granted in conversations about extraterrestrial life that there must be civilizations more advanced than we are because there are planets and stars that have had more time to produce such civilizations and we are, per the CP, probably not special. Only, see, there’s not actually anything to back up that assumption. Someone has to be first and most advanced, and until we meet somebody else, it appears that we are, however improbable that may seem.

  16. Eric,

    Again, I don’t think you’re considering just how BIG a trillion is. I also see a lot of “may” in your argument and of course if you stack the negative assumptions high enough then yes, being alone is a case that can be made. As you say later, we don’t have much data, but it’s unlikely that all of the assumptions line up on the extreme negative side (and the opposite is true of course).

    Re the Copernican principle – it’s very unlikely we’re in the middle. It’s FAR more likely we’re at the very early edge of civilizations. Again, if we look at a technological civilization as having a 50 or 100,000 year lifespan, we’re 5-10% of the way in. If such civilizations last much longer were a very very small way into the lifespan of the typical civilization.

    Likewise, Xopher, it’s unlikely there’s much life at the core of the galaxy due to the environment there. Might someone drop by? perhaps. After all, we send people into remote forests and find Neolithic tribes… Again, if a civilization is hundreds of thousands of years old, it’s FAR more advanced than we. Even if no technique for things like FTL is ever found and our basic understanding of physical laws is correct, that’s a very very long time.

  17. Well, if intelligent aliens are as bureaucratic as Terrans, you can forget physics and simply examine the budget we allocate to NASA and SETI and that figure will define the chances of encountering alien life.

    Are they out there? Definitely. But can we afford to meet?

  18. I must confess this is a topic I’ve never given any thought — I’ve just never been that curious about aliens — but this was a really interesting piece, and made me wonder about a new subject. Thanks for running it, and thanks to Seth Shostak for writing the piece. I’ll keep an eye out for the book; it really does sound fascinating.

  19. Rick: there’s a limit to the meaningfulness of a trillion. Yes, it’s incomprehensibly huge. And the gut instinct when you see a number like that is to think in comprehensible terms: “If there’s a one-hundredth of a percent chance of life evolving, then there must be 100,000,000 lifeforms out there!” Because 1/100th of one percent seems very small, but still imaginable (and if I accidentally omitted a trio of zeroes, I hope you’ll forgive me, correct it in your brain, and still see where I’m trying to go even if you still disagree with me).

    The problem isn’t with the trillion, it’s with the 1/100th of a percent or even 1/1000th of a percent or 50%; we don’t know if the chance of an intelligent civilization evolving and inventing radio is literally one-in-a-trillion or one-in-three, except to say that if it’s one-in-three it seems very quiet out there. One-in-a-trillion seems hard to believe, but there’s no objective reason for that, merely that it intuitively seems long-odds–what Dr. Shostak basically called “miraculous”–to think they’re that low.

    There’s a great John Allen Paulos quote–I wish I could find the exact line right now–about how the odds of getting dealt any specific Bridge hand, a combination of 13 specific-but-randomly-dealt cards, is one in 635 billion; and yet it would be absurd for somebody to pick up a hand of cards, look at it, compute the math and decide that he couldn’t possibly have been dealt that hand or that the hand must have been choice-picked for him. One might extend that to say that with 635 billion possibilities out there, hands just like that one must be common and this hand can’t possibly be unique because it’s so unlikely to be dealt a unique hand. If we’re alone in the universe, it’s not a miracle, and if we’re not alone, it’s not an expected outcome of the size of the galaxy or number of galaxies out there. The probability or improbability of an event that’s already occurred is basically meaningless.

    I hope we’re not alone. Meanwhile, what’s your favorite resolution for the Fermi Paradox?

  20. One might extend that to say that with 635 billion possibilities out there, hands just like that one must be common and this hand can’t possibly be unique because it’s so unlikely to be dealt a unique hand.

    Dammit! I don’t think I finished my thought there! What I meant to say is that the above conclusion–that your hand is common–would be just as absurd as concluding that you hadn’t been dealt the hand at all.

    Several trillion is several orders of magnitude above 635 billion, but I think the point is still valid whether we’re talking 1/635*10^9, 1/10^12, or 1/2 (“I had a fifty percent chance of getting this result, therefore I’m not sure if I did or didn’t!”).

  21. Eric has made some very good points here, even if he is confused about the difference between a billion and a trillion: in american usage 1 billion = 1*10E9 and
    1 trillion = 1*10E12. His points are well known and widely debated in the astrobiology community. People should look up the book “Rare Earth” by Peter Ward, professor of geological science at the University of Washington, and Donald Brownlee, professor of astronomy there. They make the same points as Eric, backed up by detailed science.
    The fact that Shostak used the word “miracle”, knowing full well that people like Ward and Brownlee disagree with him, I find intellectually dishonest (or just plain mean). The first is obviously the worst mistake a scientist can make. Ward and Brownlee, are as good at science as Shostak (and that’s being a little charitable), as are others who disagree with him and they’re just as cognizant of the relevant data.
    I say all of this even though I *disagree* with Ward and Brownlee and agree more with Shostak. Clearly, there can as yet be no winner in this debate. I always knew there was something about Shostak that just rubbed me the wrong way, and this clarifies that feeling.
    BTW, planetary scientist and SF writer David Brin has written perhaps the definitive work so far about the Fermi Paradox (non-fiction!). I think it’s available from his website but may be wrong.

  22. Or perhaps Eric is just using the expression “order of magnitude” the way a computer scientist friend once used it with me: to mean factors of 2 (!), rather the more commonly used factors of 10.

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