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Alpha Centauri Back in the News

Here I was all set to write about the discovery of carbon dioxide on HD 189733b when Alpha Centauri made its way back into the news. Twentieth Century Fox will be transmitting the re-make of the science fiction classic The Day The Earth Stood Still to Alpha Centauri on Friday the 12th, timing the event to coincide with the film’s opening here on Earth. The transmission is being handled by Florida-based Deep Space Communications Network, a private organization that offers transmission services to the public (not to be confused with the Deep Space Network that manages communications with our planetary probes).

Why does Deep Space Communications Network offer transmission services to the stars? From its FAQ:

For a number of reasons, one is because we have the equipment, and the know how so we can, and also because we thought it would be an interesting public service that is not currently available.

We’re doing it because we can…

This dubious news comes on the heels of the in many ways excellent National Geographic special Journey to the Edge of the Universe. I’m always fascinated with the way the media handle nearby stars and the planets that may orbit them, especially as our inventory of confirmed planets continues to grow, and the show’s graphics were superb, its narration gripping. But how puzzling to run into a fundamental misunderstanding about our nearest stellar neighbors.

The putative travelers have moved out through the Solar System, passing (an ingenious touch) the various probes and artifacts we humans have scattered from Mercury out to the Kuiper Belt. As we move to the nearest stars, we pass what is obviously the red dwarf Proxima Centauri and make for the binaries Centauri A and B. Describing them, the narrator says, “Not one but three stars, spinning around each other locked in a celestial standoff, each star’s gravity attracting the other, their blazing orbital speed keeping them apart.”

And then this: “Get between them and we’d be vaporized.”

Not a chance. We don’t yet know whether there are planets around Centauri A or B. But we do know that there are stable orbits around these stars, and that both of them could have planets in the habitable zone, where liquid water can flow on the surface. Their mean separation is 23 AU. There is, in other words, plenty of room between Centauri A and B for a spacecraft to move without danger of being vaporized. I feel like I’m nitpicking given the intense effort that went into this production, but it seems important to clear up misconceptions that are widely distributed.

As with the show’s treatment of Gliese 581 c. The National Geographic special shows the planet as a living world of continents and oceans, and indeed, the discovery announcement made it appear that 581 c was squarely in the habitable zone of this tiny red dwarf. But almost every subsequent study has shown this to be deeply unlikely — conditions on Gliese 581 c are probably much more like Venus than Earth. Moreover, although the show depicted the planet as rotating, so that the day/night terminator continued to shift, it’s much more likely that this planet is tidally locked to its primary, one side always facing the star.

We ran through the entire GL 581 c story here over the past few years — you can use the search function to pull these stories up. An initial euphoria (all too incautiously embraced in my opening story on the discovery) quickly gave way to skepticism. Indeed, if there is a habitable planet in the GL 581 system, it may (just possibly) be GL 581 d.

As far as Twentieth Century Fox goes, my thoughts on METI are no secret. But look, there are advocates who make a strong case for METI, just as there are reputable and serious scientists who question whether brightening our signature in the electromagnetic spectrum is a good idea. I can listen and learn from both, but what I find deeply troubling is the notion that we can take a serious issue — one that deserves thoughtful study in many disciplines — and casually throw it out the window by yet another fait accompli.

Is it too late to lock down the mania for METI? Probably, as we’re beaming everything from movies and ads for the Doritos to watch them by seemingly at will. And a case can be made that our TV and radio signals are already reaching nearby stars, and that an advanced civilization could pick them up, as well as detecting biomarkers in our atmosphere. That’s plausible, but a sudden and deliberate brightening of our signal for whatever purpose strikes me as unwise given how little we know about the conditions that surround us. I doubt seriously that such transmissions endanger us, but the point is, we don’t know, and in the absence of that knowledge, caution and further study seem a more prudent course.

Comments on this entry are closed.

  • tacitus December 10, 2008, 15:12

    It would be intriguing to see a study on the theoretical limits of detection of life-bearing planets using space telescopes of a range of different sizes up to some fleet of behemoths in the outer regions of the solar system.

    How far away can an advanced civilization be and still detect Earth and sniff its atmosphere and find those bio-markers? 300 light years? 3000 light years? 30,000 light years?

    As I’ve said before, I am wholly unconcerned about METI. As a planet, we have had our biomarkers for a billion years or more–plenty of time for many ETIs to detect us and visit us. In fact the only two reasons I can think of why they wouldn’t are (a) interstellar capable ETIs don’t exist and (b) Earth is utterly unremarkable in bearing life. In either case, there really is very little reason to fear.

    I understand the desire to have a rational, reasoned debate before doing it, but as you say, the cat’s out of the bag now anyway. However, I really don’t think the extra electronic signals add anything to the minuscule risk that might exist. The type of civilization capable of detecting them but hasn’t already detected Earth long ago is unlikely to be one that can get here any time soon. Not to mention that for all the METI stunts performed so far, the signals are very short lived, unrepeated, and targeted at a very small part of the sky. All in all, we would have to be very (un)lucky for one of those signals to be spotted by someone on the prowl for such things.

    If you are the pessimistic worrisome sort, at least you can take comfort in knowing that it will likely be at least several hundred years, and probably thousands, before a chance detection yields a visit from inquisitive ETIs. By then, we’ll have either done a number on ourselves or, more optimistically, we will be much better equipped to deal with our visitors.

  • bfwebster December 10, 2008, 15:47

    Along the same lines, the National Geographic channel has been running an ad for one of their specials, “Journey to the Edge of the Universe”. The ad’s narrator starts out by saying something like, “You’ll travel trillions of miles”, to which my immediate response was, “Yeah, and you’ll still only be a fraction of the way to the nearest star.” I suspect that they didn’t want to use “light years” or a quantifier greater than “trillion”, but seriously, “trillions of miles”? Are we out of the Oort cloud yet? It’s a bit like describing a trip around the world by saying, “You’ll travel hundreds of millimeters.”

    Later on in the same ad, the narrator says something like, “You’ll visit galaxies never [or, ‘not yet’] explored by man.” As opposed to all the galaxies we have explored?

    Thanks. I’ve been looking for a place to rant about this ad. :-) ..bruce..

  • tacitus December 10, 2008, 16:27

    Ah, the wonders of Google. All the NG folks needed to do was to enter:

    1 trillion miles in light years

    and they would have avoided the mistake (it’s only 0.17 light years).

    In fairness, trillion is about as high as most people can get their heads around (quadrillion just isn’t that well known, and even then it’s only 170 light years). It would have been better to step up to light years, I guess, then they could have dispensed with trillions altogether!

  • James M. Essig December 10, 2008, 18:02

    Hi Paul;

    I must say that I share your concern with broadcasting our presense in bold and clear signals from high gain transmitters. I like the idea of potentially setting up a communications link with any existent ETs, however, perhaps we should be careful and wiegh the consequences of doing such. Moreover, I am even in favor of the U.S. Government studying plans as to how we might defend ourselves from any future ETI incursions with hostile or less than benevolant intentions, just in case that such might be deemed necessary at some future date. However, I would very very much prefer to meet any ETI on good terms, and as a single middle age man, would be curious as to what any woman from any gender based ETI civilizations would look like.

    With all of our electromagnetic signals traveling out from Earth, out to a distance of roughly 120 light years as of 2008, I wonder if any civilizations located on other worlds might be spooked by televised rantings from the likes of Adolf Hitler, the various graphic footage that has been the subject of major network news broadcasts involving warfare, and the talk of a potential socalled World War Three, planet killing radioative fallout and firestrom smoke etc.. I am not trying to criticize our species here, but before we go broadcasting our presence in bold and clear high gain transmissions, I have to agree that some caution is in order.

    We have come very far with our electromagnetic technology with cell phones that not only have Star Trek like voice transcieving abilities, but which further have the ability to text message, recieve media alert and news broadcast notices, and which can also take and send pictures and video clips. However, we should be responsible in any attempts to sent such clear and unambiguous signals. It is interesting that our electromagnetic technology enables us to encode and transmit to any location on Earth, whether between two individuals in private or between two corporations, military commands, government organizations, secure signals that have the absolutely clear and unambiguous presentation that far out performs the fidelity of the ambiguous communications that allegedly take place between supposedly telepathic persons.

    Thanks;

    Jim

  • Adam December 10, 2008, 18:55

    Could have meant “hundreds of trillions”?

    The METI craze does seem less than rational, since it’s effectively what street-artists call “tagging” to just beam random signals (from the recipients’ point of view) all over the place, as if you’re telling other crews that you exist. If we get a “Yeah we know, now shut up” message back we’ll be lucky.

    Might be paranoia, but in the absence of any other evidence what else can we assume? If we DO detect beacons, like the Benfords described recently, what will that mean? Should we start signalling too?

  • Administrator December 10, 2008, 19:14

    Good question, Adam. How to respond to a basic beacon — as opposed to a specifically targeted message — is quite an interesting issue.

  • Benjamin December 11, 2008, 0:04

    Beaming advertisements and movies seems thoroughly pointless to me, but I think that METI is something worthwhile which we should be engaging in.

    If you think about it, there’s little that’s likely to be comprehensible from a film like The Day the Earth Stood Still, and even less so for an alien. (Sorry, couldn’t resist). You’ve got the specifications of the display mechanism, which may or may not be decipherable from the mathematics of the signal and the civilisation’s own experience; you’ve then got an array of particulars of human optics in how we actually view the film, the colour and the framerate, then after you’ve figured that out, there are a number of primates interacting with one another and with technology via yet more arbitrary conventions – and while I’ll grant that the mechanical and biological ones may be understandable, I’d be dubious as to whether a language can be adequately worked out from a single film. So they’re likely on the one hand to learn a lot about our biology and technology; but the idea that they’d be able to make a sensible judgement of our society – or want to – seems like an apocalyptic fantasy. If they had the entire corpus of our broadcasts, then it might be a thoroughly different story; I think Iain Banks did it best in “State of the Art”, which is probably my favourite short novel/novella of all time, up with “Heart of Darkness”, and my favourite science fiction besides.

    But back to the chase. We’re giving out information with these silly METI publicity stunts which is of some use to ETI in understanding us to some extent. It’s just spam. The fact that most of the email on the internet deals with enlarging bits of human men tells you that human men might want bits enlarged, but it doesn’t do much more than that. What we should really be sending is something intelligent – not just scientific information, but anything to which they could plausibly feel motivated to make a response. Advertising ploys involving METI are like, another metaphor, graffiti on the walls of Pompeii; they’d tell an interested ETI a lot about our society. What they wouldn’t do is give anything substantial to respond to – we need to give them Vergil and Horace as well.

    Let’s consider the possibilities for METI response.

    1) The trivial answer – nothing receives it because nothing’s there. Negligible loss, just the cost of sending the message.

    2) A civilisation less advanced than our own detects it. We wouldn’t suffer any harm from that: even if they had ill intentions, they couldn’t act on them, especially so long as we avoid detailing self-replicating or military technology which they might acquire. They may, however, feel moved to respond, as anyone with the technology to send a signal could plausibly reply. This would bring to us almost as great a wealth of information as it does them, and open up the prospect of long-term cultural and scientific exchange.

    3) A civilisation equivalent to our own detects it. It’s possible but unlikely that they may be aggressive: no rational person would attempt an invasion of another solar system, but I can easily imagine a Hitler or even a Bush sending hard-to-detect nuclear warheads to pre-empt some imagined future conflict. No resources would be immediately disputed and there’s no reason someone would want to invade, but it’s possible that they would want to cause maximum destruction at minimum cost so as to establish a relationship where they have the advantage in future millennia by setting back our civilisation. That’s as far as I can imagine conflict going, and there’s something like the Wait Equation going on here: the sheer time it takes to get something to another solar system, even something light like a powerful warhead or two, could mean that your opponents have developed better counter-technologies by the time it arrives, like in “The Forever War.” In short, even in the worst case scenario it’s unlikely we could suffer significantly.

    4) We transmit it to a more advanced civilisation which does not have faster than light travel. They could be hostile, as above; in which case we’ve drawn attention to ourselves and they’re very likely to be able to wipe us out. This is balanced by the fact that we don’t have anything they could plausibly want, and that a civilisation so advanced as to be able to do this without enormous effort would probably have detected biology and communications in our planet’s spectrum long before we sent out the tag. If they reply, we again find out we are not alone in the universe, which is big enough, but they may also help us achieve great breakthroughs.

    5) We transmit it to a FTL civilisation and they turn up in the Solar System. Physics seems to suggest this is a remote possibility, and anything able to do this is completely beyond my capacity to rationalise. Hypotheses non fingo. But the METI can scarcely be any more obvious to them than our halo of radio leakage anyway.

    So really, nowhere in those options is there a serious likelihood of suffering anything bad, while there’s definitely the chance to develop our understanding of the universe and of life in profound ways. We should be sending well-thought-out, obvious METI signals to all stars likely to harbour life.

  • paisley December 11, 2008, 0:48

    I see this craze for METI as a planetary size offshoot of the social networking accelerated ‘celebritisation of culture’. Far from feeling humble and small, we’re collectively going ‘look at me, look at me!” as if we were compiling a collective planetary Facebook post. I really hope this is a passing phase :)

    As far as the documentary is concerned, it always amazes me that so much care can go into special effects, story and narration, and so little care can be given to facts that, if checked, would not detract from the story one iota. Thats the power of narrative – its the story, and the characters in the story that count.

    P

  • tacitus December 11, 2008, 1:16

    I suspect a couple of things will happen if a basic beacon is discovered.

    First, every single scientific instrument on (and above) Earth capable of examining the signal will be trained on it for a long, long time — at least weeks, and probably months as every single aspect of the signal and its source — star, solar system, planet, etc — is put under intense scrutiny. The assumption will be that something else, something much weaker and/or harder to detect can be found. Even if the search never yields anything, it will be under constant watch for decades.

    Second, signals will be sent to it, even if the United Nations agrees to a ban. I could be wrong, but there’s probably enough high power transmission equipment either in the hands of private individuals or under the control of less than cooperative national or multinational entities that someone will quickly break any embargo placed by the leading nations.

    I don’t think we would send a sanctioned, repeating signal simply because without context, we have no idea what the beacon means, though its distance may factor into the final decision. If its within a few light years, it will undoubtedly make a lot of people nervous despite the fact that if it’s that close then whoever is making it probably knows we’re here already anyway. If it’s, say, 300 light years off, then there might be more temptation to send something back, but even then I doubt it would happen.

    But I would be very surprised if we spot a beacon without finding either some information included or in a weaker, companion signal. That’s why I think if we don’t find that information right away, we will assume its there but we don’t have the technology to detect it yet.

  • ljk December 11, 2008, 11:05

    This latest stunt – and it is a stunt – along with the broadcasts of that
    Beatles song and the Doritos advert is just more evidence that the
    rate and quantity of messages groups of humans will be sending
    into the galaxy will only be increasing, irregardless of the potential
    dangers to our world and species.

    Warnings no matter how legit will have about as much effect as
    the decades of warnings about the health risks of smoking and
    the subsequent prohibitions of the act in stopping everyone from
    lighting up. We are human, it is our nature to defy the rules and
    genuine risks if something makes us feel good about doing it.

    Since it is not realistic to expect everyone to stop doing METI
    any more than most of the other things we do on a daily basis
    which may or may not have negative consequences down the
    road, we need to prepare for the fact that we are part of the
    wide Milky Way galaxy and that one day our species is going
    to come across another intelligent species, either by going to
    them or they coming to us or we detect their transmissions.

    We need to at least seriously consider the potential situations
    from encountering ETI and how we might be able to deal with
    them, since our society is not going away and it will not stop
    expanding – and we sure as heck are not getting any quieter.

    I think it is amazing that so many people are so gung-ho about
    contacting alien beings, especially when you consider that the
    vast majority of ETI are portrayed as threatening monsters in
    science fiction. Perhaps more people are optimistic about our
    future in the Universe than the way Hollywood usually shows it.

  • tacitus December 11, 2008, 13:12

    I think it is amazing that so many people are so gung-ho about
    contacting alien beings, especially when you consider that the vast majority of ETI are portrayed as threatening monsters in science fiction. Perhaps more people are optimistic about our future in the Universe than the way Hollywood usually shows it.

    I think you overstate the ability of Hollywood to influence the common sense of the general public. People don’t got through life expecting to experience the next Die Hard movie or Dan Brown novel in real life. Most people can easily distinguish between reality and something dreamed up to provide thrills and excitement for a couple of hours.

    You also have to remember that many of these scifi movies portray wonderful gadgetry and advanced technologies, including FTL travel, teleportation, instant cures, and so on. So if there is any influence, it cuts both ways, positively as well as negatively.

    The people who have the most trouble distinguishing between what happens in movies and reality tend to be the pseudoscientists and conspiracy theorists. They are a group for whom the wonders of modern science and life are not enough. They chafe at what seems to them as the slow, methodical pace of progress when they believe all kinds of fantastical technology and discoveries are being covered up by some scheming government cabals.

    In any case, why should we always focus on the negative when speculating about contact with ETIs? As others have said, the positive possibilities are endless. Just knowing that we’re not alone in the Universe would be a profound discovery even though our daily existence would not change much as a result, but what if we were suddenly introduced into a commonwealth of intelligent civilizations that no longer suffers the shortages and conflicts that plague humankind? It would transform our lives in ways we can barely even imagine. Fun stuff.

    In the end, we just don’t know what would happen, and given the myriad of extremely pressing concerns our governments have to deal with right now — like global warming and the global recession — I really have no problem with our leaders deciding that what to do in response to the variety of unlikely alien contact scenarios is not even close to the top of their agenda.

  • Mark Wakely December 11, 2008, 13:31

    If the movie is eventually viewed on some distant planet inhabited by an advanced warrior race with FTL capabilities, let’s hope they don’t think it’s a “how to” documentary…

  • ljk December 11, 2008, 14:53

    What the aliens might really think if they ever saw TDTESS and
    understood it is “Wow, these humans don’t have a clue about
    the intelligent life forms in this galaxy, do they?”

    Tacitus, as for that sentiment about how we might learn how to
    survive and live from ETI who also kept from destroying their
    own culture and species, I presume such a lesson would only
    work if they were similar to us. My guess is that alien species
    are not necessarily humanoid in design and even less human
    in thought, action, and culture outside of some very basic
    common traits such as consuming food and reproduction.

    And it would not surprise me if I was way off on those as well.

    We keep thinking (and hoping) that ETI aren’t too different from
    us, even though we at least know we are looking for beings who
    may not look or act anything like us and who probably evolved
    in very different environments. I know if they are too alien then
    we may not be able to communicate or even recognize one
    another, but if we are just looking for variations of ourselves,
    then what is the point? As Stanislaw Lem once said, man doesn’t
    want planets, he wants mirrors.

    I keep coming to the conclusion that something much smarter
    than us may be required to properly explore the galaxy and
    find and communicate with its residents. Not that the fact we do
    have at least an inkling of the concept and that we should at
    least try our best isn’t admirable, please note.

  • tacitus December 11, 2008, 16:32

    Tacitus, as for that sentiment about how we might learn how to
    survive and live from ETI who also kept from destroying their own culture and species, I presume such a lesson would only work if they were similar to us. My guess is that alien species are not necessarily humanoid in design and even less human in thought, action, and culture outside of some very basic common traits such as consuming food and reproduction.

    I agree there is a tendency to place human concepts and ideas into the minds of ETIs. It’s all we know, after all. And I accept that an ETI species is unlike to look like us (hence my extreme skepticism of the existence of little green men, grays, etc), but we do still share a lot in common with any ETI that happens to be out there.

    First, our fundamentals of maths and physics are the same (obviously) and it’s very likely that the evolutionary process governing their ascent to a technological society are the same (even if the route we take is very different). So it would seem likely that the social constructs we evolved, like cooperation, loyalty, religion, and competitiveness, are commonplace too, even if they are rationalized in a different way. I suspect we will have enough in common to understand each other’s behavior given enough chance, even if we end up as enemies.

    I guess my greatest uncertainty over how an ETI would react to contact with us is in the area of religious belief. In our culture, religious fundamentalism is still (unfortunately) very healthy despite our major advances in science and technology, so it’s not unreasonable to believe that such a powerful cultural construct could survive as a major driving force in a space-faring ETI. Perhaps they believe that the Universe will only be perfected once all other life is wiped from existence and so they have no choice but to embark on a galaxy-wide crusade against all life forms. If they do turn out to be hostile to us, I very much doubt there will be a rational explanation for it.

    But I prefer to be optimistic. I know I have no evidence for that, but then there is no evidence for taking any position at this point!

  • Ronald December 12, 2008, 4:45

    Tacitus says:
    “I guess my greatest uncertainty over how an ETI would react to contact with us is in the area of religious belief. In our culture, religious fundamentalism is still (unfortunately) very healthy despite our major advances in science and technology, so it’s not unreasonable to believe that such a powerful cultural construct could survive as a major driving force in a space-faring ETI. Perhaps they believe that the Universe will only be perfected once all other life is wiped from existence and so they have no choice but to embark on a galaxy-wide crusade against all life forms. If they do turn out to be hostile to us, I very much doubt there will be a rational explanation for it.”

    I agree, but my hope and expectation is that there is a kind of self-regulating and self-selective mechanism at work here: a too aggressive and narrow-minded society will probably never make it to the level required for interstellar travel, either because they will not develop the required technologies and levels of organization, or they will self-destruct in a more primitive stage. In this way the immense gap between the stars functions as a safe barrier and selection mechanism. Natural selection at the cosmic level.

    Maybe, though, we should feel sympathy for living planets in a multiple living planet system or in a binary system, where such a self-selective mechanism, even if it indeed exists, might not work so effectively, and a politically/religiously radical society could impose its destructive world-view more easily on the neighbors. I sometimes envy the idea of being part of a (wide) binary system (such as Zeta Reticuli), each with a living planet. This would create an enormous incentive for ‘interstellar’ space travel and colonization. But at the same time it would also constitute a great ethical risk.

  • Ronald December 12, 2008, 4:56

    On a more ironic note: what I fear the most are not so much the truly agrressive civilizations, because, from an evolutionary standpoint, they will most likely burn themselves up quickly, like very aggressive diseases.

    What I fear more are the cosmic parasites, a specific type of civil servants, the galactic bureaucrats, that will impose all sorts of new galactic regulations and taxes upon us, or withhold great ideas and solutions from us for another number of millennia, simply because we haven’t filled out the proper forms in time.

  • David December 12, 2008, 8:03

    Yes, this is a stunt and not even an effective one. Seth Shostak has pointed out that except for the most powerful radar signals, radio signals from Earth are unlikely to have traveled more than a couple of light years.

    These signals are unlikely to go even that far. The antenna they are using for the broadcast has a diameter of 5 meters which is small compared to that used by the military or in radio astronomy where antenna diameters are
    say 30 to 300 meters.

    This matters because broadcast power is proportional to the area of the transmitting antenna so everything else being equal, we are not talking about a reduction of broadcast power by 5/30 to 5/300 or 1/6 to 1/60 but of factors of 1/36 to 1/3600. Everything else is unlikely to be equal so the reduction in power is likely to be more.

  • andy December 12, 2008, 8:06

    METI is clearly not being taken seriously because there does not seem to be any strategy in place in case of a response. As has been said upthread, a lot of it is silly advertising stunts with no thought to any kind of consequences arising from carrying out METI operations.

    METI proponents seem to find it much easier to try to convince everyone that nothing bad could possibly happen rather than trying to propose any kind of strategy that would help to avoid or reduce the effects if and when such things occur. This is not a sensible strategy from a safety point of view: it doesn’t actually matter how many people you manage to convince that the Titanic will not sink, what matters is what measures are in place to deal with the situation when it happens.

    In any case, why should we always focus on the negative when speculating about contact with ETIs? As others have said, the positive possibilities are endless.

    Let’s rewrite that slightly…

    In any case, why should we always focus on the negative when speculating about building nuclear power stations? As others have said, the positive possibilities are endless.

    Or how about…

    In any case, why should we always focus on the negative when speculating about using asbestos to fireproof buildings? As others have said, the positive possibilities are endless.

    See?

  • tacitus December 12, 2008, 12:55

    Ronald:
    What I fear more are the cosmic parasites, a specific type of civil servants, the galactic bureaucrats, that will impose all sorts of new galactic regulations and taxes upon us, or withhold great ideas and solutions from us for another number of millennia, simply because we haven’t filled out the proper forms in time.

    That would be the Vogons, right? :-)

  • tacitus December 12, 2008, 13:14

    andy, your analogies are a bit of a stretch. We can quantify the risks of using nuclear power and asbestos, so it’s possible to do a detailed cost-benefit analysis on both of them. We know absolutely nothing about ETIs — not even that they exist, so any risk assessment is essentially a grope in the dark.

    And what little we do know tends to favor the conclusion that an unprompted, undirected METI is unlikely to do harm:

    1) The signals are weak and fleeting.
    2) Many of the target systems are likely to have no inhabitable planets.
    3) We haven’t a clue if any of the target systems has an inhabitable planet, let alone an ETI civilization. Odds are none of them has.
    4) The distances involved are massive. It is likely many thousands of years, at least, before we could expect a visit in response to a message.
    5) If FTL travel is possible, or ETIs are commonplace, they most likely know we’re here already, and may even be here observing us, so METI does not add to the risk of discovery.

    Off the top of my head I can’t think of one quantifiable risk that would indicate that more caution was needed over METI. Perhaps you can come up with some?

  • ljk December 12, 2008, 15:37

    If there is anyone at Alpha Centauri to receive the remake of
    TDTESS, it sounds like they won’t be getting one of our finer
    cinematic efforts:

    http://www.cnn.com/2008/SHOWBIZ/Movies/12/12/review.day.earth.still/index.html

    And nothing like sending a film about an alien coming to Earth
    to destroy our species into the Milky Way to give someone ideas.

    Thankfully it sounds like the group doing the broadcasting does not
    have the necessary equipment to get the film very far into space.

    I wonder how many of their customers know this before they shell
    out good money under the pretense of conducting METI?

  • andy December 12, 2008, 20:30

    We know absolutely nothing about ETIs — not even that they exist, so any risk assessment is essentially a grope in the dark.

    Same goes for any possible benefits of contact with ETI. What little we do know suggests the benefits would be minimal: the difficulty of setting up meaningful communication with a species that has very little shared context with us beyond existing in a universe with the same laws of physics is going to be the major stumbling block here (Stanisław Lem has already been mentioned upthread).

    Unfortunately for trying to dismiss focussing on the negatives of METI, the risks may go as far as affecting the entire planet, and safety analysis means that worse case scenarios should be considered (there seems to be very little material that treats METI using the methodologies from the development of safety-critical applications, which is somewhat worrying given the possible levels of bad consequences). Thus they should be very carefully considered and any assumptions we throw in (e.g. your statement that FTL-capable civilisations would know about us by now – maybe, but there’s no guarantee that such a civilisation would have surveyed our radio light cone yet: it’s a large galaxy) should be rigorously analysed.

    And risks come in many forms other than the ETIs coming along and smashing up the planets with relativistic missiles. How about this scenario which doesn’t involve hostile action by the ETI: we attract the attention of a civilisation, get a return signal, everyone enthusiastically transmits loads of data about everything to the aliens (the “NOTICE MEEEEE!!!” mentality that’s already been mentioned), they reply with something along the lines of “thanks for the taster, now let’s negotiate for exchange of information about cultures, technologies, etc.” and we find we’ve already transmitted most of the stuff we’re interested in. Earth civilisation ends up a pauper on the galactic internet. I think David Brin used this scenario as one of the examples of a METI-related risk.

  • tacitus December 13, 2008, 3:14

    andy, my risk assessment list was an attempt to enumerate the (at least partially) quantifiable risks of sending a METI signal, and assumes that we have not identified an ETI signal yet. I would argue that most of your reply is talking about risks of making contact (which is not quite the same thing) and we have no way of quantifying them in the absence of that contact. We simply just don’t know what the mindset of an ETI will be.

    Until we find a signal or evidence of ETIs living on an exoplanet, we don’t know where to aim a METI signal. Therefore, I was arguing, there is very little risk in doing so since the odds of it being received are next to zero.

    Once we find a signal, that’s a different proposition. It would be wise, of course, to study the signal and its source before any risk assessment is made, and that could take years. No doubt, based on the findings, all kinds of scenarios good and bad will be dreamed up and debated endlessly, and I suspect that reaching a consensus over what to do will be next to impossible.

    But I do expect that there will be several unofficial attempts to send a METI, one or two of which will probably be quite powerful signals. I just don’t see how you can prevent it short of impounding every transmitter believed capable of sending one, which is unlikely to be possible.

    Thus they should be very carefully considered and any assumptions we throw in (e.g. your statement that FTL-capable civilisations would know about us by now – maybe, but there’s no guarantee that such a civilisation would have surveyed our radio light cone yet: it’s a large galaxy) should be rigorously analysed.

    I disagree with your premise here. Given that interstellar travel is likely to be incredibly more difficult than observing from a distance (even if FTL is possible), then it is very likely that an ETI civilization curious about the rest of the galaxy will have invested heavily in telescopes far beyond anything we have today. Surveys of exoplanets will have been made, including whether or not there are chemical markers for life in their atmospheres.

    Given that life has existed on Earth for almost 4 billion years, our biosphere has been detectable over a large portion of our side of the galaxy for a long long time (out to the theoretical limit of detection, whatever that is — I have no clue!).

    Once our biosphere is detected, the ETI’s interest in us probably depends on how commonplace life is in the galaxy. If it’s very rare, then the odds are they have already dropped by to take a look (if they can). If it’s commonplace, then perhaps we may be ignored if there are better or closer targets to focus on, but then there’s also a good chance that we’re of less value to them as a target for invasion or occupation too, since “living space” would not be as much of an issue.

    Either way, unless by some small chance, the ETIs out there are only a few hundred years ahead of us in technological terms, all this is probably moot. Most estimates for the amount of time it would take for a sufficiently advanced ETIC to explore the whole galaxy is anywhere from 100,000 to 500,000 years. That’s a blink of an eye in terms of galactic history, so if there are any old ETIs out there, Earth is just “been there, done that” to them.

  • Jim Lewis December 13, 2008, 9:22

    Really like your website so much so I felt compelled to comment.

    The debate of what messages we send into space is a long and old one. Many argue we should only send Earth’s best, such as Bach or Van Gogh, but would that really be a fair representation of Earth? Some may say that sending only the greats would more like bragging then trying to communicate. I think if you really think about it, sending this film, The Day The Earth Stood Still gives a fairly accurate representation of Earth and how Earth may react to an Alien Visitor. If you don’t agree, tell me what you would send; the movie ET?

  • andy December 13, 2008, 10:31

    tacitus, you have changed the terms of the argument. The issue is not contact between an ETI and the biosphere, it is contact between an ETI and humanity.

  • Administrator December 13, 2008, 14:37

    Jim Lewis writes:

    The debate of what messages we send into space is a long and old one. Many argue we should only send Earth’s best, such as Bach or Van Gogh, but would that really be a fair representation of Earth? Some may say that sending only the greats would more like bragging then trying to communicate. I think if you really think about it, sending this film, The Day The Earth Stood Still gives a fairly accurate representation of Earth and how Earth may react to an Alien Visitor. If you don’t agree, tell me what you would send; the movie ET?

    Jim, thanks for joining in — a pleasure to have you. My argument isn’t about which work of art or science to send as a message, but whether we should do anything to call attention to ourselves at all, without more knowledge of the universe around us. If I had to choose something that would be sent, I suppose I’d go for something like the Voyager record, but I leave that to more capable hands. My issue is whether or not to send in the first place.

  • tacitus December 13, 2008, 15:50

    andy, I’m arguing that *if* there are ETICs out there, then in all likelihood biosphere detection comes waaay before radio signal detection, and unless there are millions of life-bearing planets in the galaxy, we would therefore have already attracted attention as a rare and interesting planet long before we became a technological society. And if we’ve already attracted some attention, then arguments over the risks of METI are moot.

    Even if the ETIC had spotted out biosphere and decided we weren’t worth the effort of a visit until there were signs of intelligence, then we still would likely betray our presence decades, if not centuries before any of our METI signals could reach them.

    Again, I am assuming that a ETIC not much more advanced than us (perhaps 1000 years?) would have a fleet of exoplanet survey telescopes placed in the outer solar system continually scanning for hundreds of light years in all directions. Once a live biosphere has been detected, it would stand to reason that even if they didn’t send an interstellar probe, they would continue to monitor the planet’s reflected light for spectral changes denoting significant events happening on the planet. They would, for example, probably be able to detect the asteroid strike 65 million years ago, given the massive upheaval it caused. But, more importantly, if their equipment was sensitive enough, they would be able to detect the pollution in our atmosphere some time after industrial revolution. Not only that, but within the last few decades, the night time hemisphere would probably be giving off a huge signal in the sodium emission part of the spectrum from the billions of street lights being used. Signs of intelligence would be unmistakable.

    So, what does that all mean?

    First, it make METI all but irrelevant from a detection point of view. Unless an ETIC just happens to be in the very narrow band of history between the beginning of detecting radio signals in space and the beginning of deep and comprehensive exoplanet surveys — perhaps 250 to 500 years max — then it’s almost certain that our presence on the planet will first be detected by their exoplanet survey telescopes examining our biosphere.

    Second, short of erecting a beacon blasting powerful radio waves in all directions, the pollutants in our atmosphere and nighttime illuminations will be more easily detected than any METI signal. All an ETIC needs to do is to point their telescopes in our direction once every decade looking for technologically induced changes in our planet’s spectrum.

    I agree that this is all speculation, but I have yet to see a good argument against the likelihood that an ETIC won’t already have observed millions of exoplanets in details before they have even set foot our of their solar system. It’s simply orders of magnitude easier to develop bigger and better telescopes than it is to build a fleet of interstellar craft. Thus space exploration beyond the bounds of their solar system will be mostly an armchair exercise for hundreds, if not thousands of years.

    Just look at where we are. We only detected the first exoplanet a mere decade ago and we now know of hundreds and have even begun to image some of them. This is all with first generation exoplanet hunting equipment. Where will we be in another 100 years, another 200? We are likely to still be confined within our solar system for one (with perhaps an unmanned probe or two out in the Oort cloud on the way to Alpha Centauri), but I’d wager that we will have a massive catalog of exoplanets, numbering in the hundreds of thousands, including images and spectral analyses of most of them. Even when we do set off to the stars in earnest, it will still be much more cost effective and incredibly less time consuming to explore from long range (assuming FTL remains science fiction).

    Anyway, it’s a fun discussion, so thanks for keeping the replies coming!

  • Ron S December 13, 2008, 16:15

    Speaking of METI threats, here is the supposed risk that really got folks worried about this transmission (from the New York Times):
    http://www.nytimes.com/2008/12/12/science/space/12earth.html

    “…the company had to satisfy 20th Century Fox, the film’s producers, that the transmission could not be intercepted and pirated on Earth or in the air.”

    Apparently we don’t want all of our cultural products freely distributed on those A2A (Alien-to-Alien) interstellar networks.

    Shostak was also quoted in the article, downplaying the probability of ETI interception. As for my own opinions, I’ve stated them here often enough.

  • ljk December 13, 2008, 20:13

    At least it sounds like they tried to get some of the science right
    in this “reimaging”:

    http://www.nytimes.com/2008/12/11/us/11pasadena.html?_r=1

    By the way, can Alpha Centauri be seen from Florida? That is
    where this company that charges $299 for people to beam
    messages into space is located.

  • ljk December 13, 2008, 23:48

    An addendum to my last post in this thread.

    I asked a friend if Alpha Centauri can be seen from Florida,
    and this was his response:

    “Just barely. The southernmost point in CONUS is Key West, FL, at 24d 30m N Lat. Theoretically, the furthest south you can see from there is is (90 – Lat) = Dec -65d 30m. Alpha Cen is at declination -60d 52′.

    “It pops up a few degrees over the southern horizon for a few minutes each day.”

    So unless that Deep Space Communcations Network made a
    diligent effort to be in the right place and time to aim their
    TDTESS broadcast to our nearest stellar neighbor, I might have
    to wonder exactly where they aimed the film at?

  • Gregory Benford December 14, 2008, 0:50

    Administrator & Adam:
    I rather agree with:
    Good question, Adam. How to respond to a basic beacon — as opposed to a specifically targeted message — is quite an interesting issue.
    –because that’s what we’re likely to see, at least in the radio/microwave spectrum. We assume the beacon points to some lower power, information-dense companion signal (though this may be a cultural assumption, too). Response will depend on whether there is such a companion, and if so, what it “says” — given the difficulties of species/culture/language differences, that opens an immense choice of imaginary responses. Food for many stories!

  • Administrator December 14, 2008, 9:45

    ljk writes:

    So unless that Deep Space Communcations Network made a
    diligent effort to be in the right place and time to aim their TDTESS broadcast to our nearest stellar neighbor, I might have to wonder exactly where they aimed the film at?

    Larry, let’s ask Jim Lewis about this. He’s managing director of Deep Space Communications Network, which sent the message, and he’s here in the thread — he commented yesterday. Jim, maybe you can give us some info about the logistics of a beamed signal like this to an object quite low on the horizon.

  • sparckyz December 14, 2008, 19:35

    ET better watch out.. it will have the MPAA on its ass!! lol

  • Ronald December 15, 2008, 12:31

    tacitus Says:
    December 12th, 2008 at 12:55

    That would be the Vogons, right? :-)

    I had those in mind, indeed! (although some earthly bureaucracies come scaringly close ;-) ).

  • George Dishman December 15, 2008, 12:44

    Have a look at the simulated images of Earth at various resolutions in the New Worlds Imager study, page 39:

    http://casa.colorado.edu/~wcash/Planets/new_worlds.pdf

    Then think what this picture would look like at 300km resolution:

    http://www.msstate.edu/dept/Biochemistry/faculty/boyle/uhpfiles/earthlights.jpg

    If we have the technology to achieve that sort of image, does it really matter whether we beam a beacon into space or not? Any alien curious about our planet would see our technology (street lights!) blatantly obvious in our spectrum, and due to international cooperation, they burn 24/7 on the night side of our planet.

    George

  • Ron S December 15, 2008, 17:02

    To see human lighting you need a full view of the night side. That can only happen from a location closely-aligned with our orbital plane and during a (near) transit.

    This would make it very difficult to separate Earth’s weak signal from that of the Sun since the angular separation would be tiny at best. At other angles, even small ones, I would expect that the radiation from the day side would swamp a sodium or similar signal from the night side.

  • ljk December 16, 2008, 0:36

    Klaatu barada stinko

    The producers of the remake of “The Day The Earth Stood Still”, as a publicity stunt, transmitted the film last week towards the nearby star Alpha Centauri.

    James Oberg explains why, if there’s anyone there, they have no chance of actually watching the film.

    http://www.thespacereview.com/article/1269/1

  • George Dishman December 16, 2008, 7:14

    It depends on the resolution and the range. With the NW Explorer, measurements would be made of the whole planet so the dark-side component would need to be separated spectroscopically from the day side light. Note though that the reflected light would have a spectrum similar to that of the Sun while that from Earth’s night side would have a significant component of the sodium doublet from low pressure and high pressure lamps. That component would vary over the day because the Pacific region emits less than Europe, Africa and Asia. It would also vary over the year since there is little artificial light on the day side so as you say it would peak near transits.

    With the Imager, acheiving 300km resolution would significantly improve the isolation and ‘swamp’ in the sense of pixel overload is unlikely to be a problem, the pixel counts would be very low indeed. The paper notes that the system would be photon limited at 10km resolution (page 44).

    Given that we are just in the first decades of this sort of technology, any speculations about alien technology must surely account for multiple generations of such imagers and the ability to deal with the concerns you raise within the limits only of what is theoretically possible. I’m sure if we saw hints of the spectrum of artificial lighting on the night side of a planet, it would give a significant impetus to the development of better imagers capable of seeing what was producing it.

    George

  • Thomas December 16, 2008, 22:19

    At the oklo blog

    Bruce01:
    “Alpha Centauri, at declination -60 degrees, is barely above the horizon even from Florida. The web site:
    http://www.deepspacecom.net/
    says they are located near the Kennedy Space Center which is north of latitude 28 degrees. This makes the zenith angle of Alpha Centauri greater than 88 degrees as seen from the Space Center. You need to add to your equation the probability that the “beamed” signal made it through the Earth’s atmosphere without being totally scattered.”

    Greg’s response.
    “Indeed. Furthermore, for the entire duration of the broadcast, Alpha Cen (RA 14h:39m, DEC -60deg:50min) was below the horizon as viewed from 28 35 06N, 80 39 04W. One can’t help but wonder whether bruce01 may have made a vital contribution to the solution of the long-running Fermi Paradox.”

  • ljk December 19, 2008, 12:30

    At least the “reimaging” has stirred up some good, thought-provoking
    discussions on the issues of humanity’s place in the Universe and our
    actions on and to Earth, plus what would happen if we encountered a
    superior intelligence:

    http://blogs.discovermagazine.com/cosmicvariance/2008/12/15/if-aliens-decided-to-destroy-humanity-could-we-blame-them/

  • Administrator December 19, 2008, 14:10

    The piece from Cosmic Variance was quite good. I particularly liked this, which meshes with my own thinking about METI:

    The problem is, it wouldn’t be a clash of civilizations; more likely, from the aliens’s perspective it would be like the clash of an annoyed homeowner dealing with mildew, or perhaps an infestation of cockroaches if we’re feeling generous. Turning again to experience, human beings are right now causing one of the great mass extinctions in the history of the planet. We could stop killing off other species, but we find that it would slightly cramp our lifestyle to do so, and we decide not to make that sacrifice. True, when we send spaceships to Mars and elsewhere, we are very careful to take steps to ensure that we don’t contaminate any traces of life that might be clinging to the other planet. But clearly, that’s not because we place great value on the continued existence of any one species. Rather, it’s because (to us) any kind of life on another planet would be incredibly unique and interesting. But there’s no reason to believe that we would be all that unique from the perspective of a galaxy-weary alien civilization. They may well have bumped into millions of worlds featuring all sorts of life. If we’re lucky, they might give us the respect that a human being would show an ant colony or a swarm of bees. If we’re lucky.