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New Paper Offers Additional Reasoning for Fermi's Paradox 774

KentuckyFC writes "If the universe is teeming with advanced civilizations capable of communicating over interstellar distances, then surely we ought to have seen them by now. That's the gist of a paradoxical line of reasoning put forward by the physicist Enrico Fermi in 1950. The so-called Fermi Paradox has haunted SETI researchers ever since. Not least because if the number of intelligent civilizations capable of communication in our galaxy is greater than 1, then we should eventually hear from them. Now one astrophysicist says this thinking fails to take into account the limit to how far a signal from ET can travel before it becomes too faint to hear. Factor that in and everything changes. Assuming the average communicating civilization has a lifetime of 1,000 years, ten times longer than Earth has been broadcasting, and has a signal horizon of 1,000 light-years, you need a minimum of over 300 communicating civilizations in the Milky Way to ensure that you'll see one of them. Any less than that and the chances are that they'll live out their days entirely ignorant of each other's existence. Paradox solved, right?"
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New Paper Offers Additional Reasoning for Fermi's Paradox

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  • by the_humeister ( 922869 ) on Monday February 02, 2009 @03:06PM (#26697681)

    We humans are God's only children. That's why there's no one else in the universe. And the universe was created 6k years ago. Duh! Scientists... what useful things have they ever done other than bring up heresy?

    • by gnick ( 1211984 ) on Monday February 02, 2009 @03:12PM (#26697773) Homepage

      ...the universe was created 6k years ago.

      Hey - There's no room for rounding if you're going scriptural on us. The Earth's creation started the night before Oct 23, 4004 BC. [] (In case anyone was wondering, Earth is a Libra.)

      • by Amazing Quantum Man ( 458715 ) on Monday February 02, 2009 @03:34PM (#26698099) Homepage

        Is that Julian or Gregorian?

        • Re: (Score:3, Informative)

          by gnick ( 1211984 )

          Proleptic Julian calendar. [] Dates in the BC range (and all the way into the late 16th century AD) are typically assumed Julian unless explicitly stated Gregorian. Although I have no idea what the proper technique would be to handle the who Julian leap-year mess and figure out whether Earth really is a Libra or actually a Scorpio with a funny birthday. If only Ussher was still around we could ask him.

          As a side note (as if this whole thing isn't a side-note), Lightfoot [] also put the Earth's birthday near the

          • by CecilPL ( 1258010 ) on Monday February 02, 2009 @04:07PM (#26698617)
            When calculating astrological signs over timescales of millenia, don't forget that due to precession of the Earth's axis [] the signs all shift by about a month every 2,000 years. So today's Libra is the year 4000's Virgo.

            (Except of course that all the dates for the signs are fixed as they were in the time of the Ancient Greeks, so we're already off by a whole month. If you're a Libra the sun is actually in Virgo on your birthday.)

            This also means that the autumnal equinox in 4004 BC was somewhere around the end of June.
      • by turtledawn ( 149719 ) on Monday February 02, 2009 @03:38PM (#26698163)

        That explains the drama-queen mood and temperature swings, then.

      • Re: (Score:3, Funny)

        by geobeck ( 924637 )

        The Earth's creation started the night before Oct 23, 4004 BC.

        ...five, six, seven... so it finished on Halloween? That explains a lot.

        • Re: (Score:3, Informative)

          by KevinKnSC ( 744603 )

          Might want to try that math again, hot shot. Hint: 23 + 6 = 29.

        • Re: (Score:3, Insightful)

          by mdielmann ( 514750 )

          Um, how about this? 23, 24, 25, 26, 27, 28, 29. That's 7 days, inclusive, and given the GP's statement, the 23rd would be the first day. So you failed twice. First, 23 + 7 is 30, not 31. Second, you forgot the inclusion note.
          Don't worry, you're not the first person I've met who fancied himself a nerd and couldn't do date math properly.

          I'm sure there's a joke in there somewhere about nerds not getting it all makes sense.

      • Re: (Score:3, Insightful)

        by Thaelon ( 250687 )

        The chronology is sometimes called the Ussher-Lightfoot chronology because John Lightfoot published a similar chronology in 1642-1644. This, however, is a misnomer, as the chronology is based on Ussher's work alone and not that of Lightfoot.

        Ahh wikipedia. Nothing like seeing an article refute itself mid-paragraph.

      • by slashdotlurker ( 1113853 ) on Monday February 02, 2009 @05:35PM (#26700053)

        (In case anyone was wondering, Earth is a Libra.)

        Not to nitpick or anything, but the Earth cannot have a zodiac sign, since the latter is usually defined as the constellation in the ecliptic that the Sun was present in. Which presumes that the observer was located on the Earth. Ergo ...

    • Re: (Score:3, Informative)

      Looking at the current moderation, it looks like Poe's law [] is in effect, and the_humeister just got charged as an adult.
    • by mcrbids ( 148650 ) on Monday February 02, 2009 @05:15PM (#26699749) Journal

      Fermi's paradox is paradoxically absent any real facts. We know not nearly enough to know if it's even relevant.

      For example, one prime assumption is that alien life would communicate on the EM spectrum someplace using technology similar enough to ours to be in a form that we would understand or recognize. Yet dolphins are quite intelligent, and we have no idea what they are saying. If we can't decipher communication in a biological form that's based on the same exact biology as ourselves, that is 99% identical at the cellular level, how can we justify our arrogance in believing that we'd know truly alien communication if we saw it?

      Obviously, if we did come across some communication on the EM spectrum that we were to show wasn't some mere physical process, we'd have proof of alien communication or related phenomena. But there's no evidence at all that they would. In fact, it's rather unlikely that we will ourselves, in just a few years: take a look at spread spectrum transmission [] for a method that we already use today in many uses that would be virtually undetectable by SETI.

      Fermi's paradox is based on a large number of assumptions of scale that are, quite frankly pulled from Fermi's backside, and aren't even well supported by technological developments since its inception. They are the best assumptions available, but they demonstrate nothing other than a weak foundation for conjecture.

      And if some of those assumptions are already demonstrated irrelevant with applicable technology HERE, TODAY, how can we give Fermi's paradox any more than the time of day?

  • by gnick ( 1211984 ) on Monday February 02, 2009 @03:07PM (#26697697) Homepage

    Assuming the average communicating civilization has a lifetime of 1,000 years...

    Damn - We've got less time than I thought. Here I've been rooting for heat death. =(

  • What paper? (Score:4, Informative)

    by zappepcs ( 820751 ) on Monday February 02, 2009 @03:07PM (#26697703) Journal

    No link to anything but Wikipedia and a blog?

    • by b4dc0d3r ( 1268512 ) on Monday February 02, 2009 @03:41PM (#26698219)

      I don't know about you, but I prefer a link to a blog over the actual paper. Mostly because I don't speak Astrophysicsese.

      I went ahead and clicked on the blog for you, and the link. Here's the paper (You can get a PDF if you want), it was submitted to the International Journal of Astrobiology. []

      I understand your reluctance, after all you're the one who posted:

      The last damn thing I want is to click a link out of curiosity and within five minutes be standing there having to listen to the IT guy say "here's your sign" or end up in the HR office explaining my seeming poor hand-eye coordination because I accidentally clicked on a link in an email from the fscking HR department. Don't these people have enough work to do? []

      Don't worry, you can continue to click on links out of curiosity. I put one above, go ahead, click it. You know you want to. everyone else is clicking it. Now with more fiber, and it cures Alzheimer's too.

  • Solved? (Score:3, Insightful)

    by MutantEnemy ( 545783 ) on Monday February 02, 2009 @03:09PM (#26697733) Homepage

    "Paradox solved, right?"

    No. Some planets suitable for life have almost certainly existed in this galaxy for billions of years longer than the Earth. By now, one would expect there to have been civilisations that spread throughout the galaxy and therefore brought Earth within detection range of their signals...

    • Re:Solved? (Score:5, Interesting)

      by Amazing Quantum Man ( 458715 ) on Monday February 02, 2009 @03:12PM (#26697775) Homepage

      And if they're communicating by some mechanism that we can't read? E.g. the equivalent of "subspace radio".
      Or maybe it's a point to point via laser (see Niven's Known Universe).

      • Re:Solved? (Score:5, Funny)

        by Propaganda13 ( 312548 ) on Monday February 02, 2009 @03:21PM (#26697903)

        Exactly. Maybe all those "crazy" people are actually talking to aliens.

      • Re:Solved? (Score:5, Interesting)

        by defile39 ( 592628 ) on Monday February 02, 2009 @03:23PM (#26697953)

        True. The calculation of 1000 years seems a bit too long. We can't figure out how to shorten it because we don't know how long we're going to be using broadcast signal based communication as opposed to some other more direct means.

        Besides . . . attempting to extrapolate with so many unknowns is, at best, an exercise in postulation. At worst, it is dangerously misinforming.

        • Re:Solved? (Score:5, Funny)

          by hax0r_this ( 1073148 ) on Monday February 02, 2009 @03:50PM (#26698357)
          The 1,000 year thing seems like the weak point of this theory. Sure, most communicating civilizations may not last more than 1k years (and this is an idea based entirely on observation of our own civilization). But as soon as you get interstellar travel, how likely is it that the species manage to die off entirely in a short span? Its easy enough to wipe out one planet, but what about the next? And every spacecraft that manages to escape?

          Right now our civilization is like a closed source application running on a dev box off the network. If the hard drive dies, the code is toast. But as soon as you get that code in Git, its a whole lot harder to kill.

          Ok, so that was a terrible analogy.
          • Re:Solved? (Score:5, Interesting)

            by jdmetz ( 802257 ) on Monday February 02, 2009 @04:43PM (#26699185) Homepage
            The 1,000 years isn't time from broadcasting to die-off. It is time from broadcasting to narrowcasting (using lasers or some other communications method that directly targets the intended receiver). Once narrowcasting is in use, we wouldn't expect to hear them unless they know we are here and are specifically targetting us.
          • Re:Solved? (Score:4, Interesting)

            by Wooky_linuxer ( 685371 ) on Monday February 02, 2009 @05:41PM (#26700127)

            First,you assume interstellar travel is possible. What if it isn't? What if the only ways to travel in space are no much better than the ones we know? We'd be all restrained to our own star systems. Perhaps we can have space stations and colonies in nearby planets and moons, but not much more than that. Perhaps they can't be self sustainable. Perhaps the likehood of finding another environment in another planet that can be converted to supporting life without an extreme expense of energy is extremely low.

            AFAIK, the Fermi paradox has nothing to do with interstellar travel. It only assumes things that we already know, and hence are definitely possible - using radio waves as a means of communication. I myself think this may be too much of an assumption.

          • Re:Solved? (Score:5, Insightful)

            by radtea ( 464814 ) on Monday February 02, 2009 @06:34PM (#26700793)

            The 1,000 year thing seems like the weak point of this theory.

            Actually, the estimate of the probability of the kind of intelligence that makes complex machines is a bigger problem, and a plausible solution to the paradox.

            We have ample evidence that if a thing is possible at all, evolution will reproduce it many times. Wings, fins, eyes... all of these optima have been found many times, across genera and families and whatnot. By one estimate the eye has evolved independently a couple of dozen times, based on the proteins used in the retinal structure.

            There was an article here on /. a while back pointing out that two birds previously believed to be related were the result of convergent evolution. Evolution finds the same optima over and over again.

            The kind of intelligence that makes complex machines has evolved on Earth exactly once, and that is the only kind that is of interest in Fermi's Paradox.

            Furthermore, the current best guess at the evolutionary driver of kind of intelligence that makes complex machines is that it's a peacock's tail, and extravagant sexual display that had relatively little utility outside of attracting a mate or two. Therefore the whole "making complex machines" aspect of our intelligence is more-or-less an accident, not the result of direct selective pressure at all.

            Men are very slightly better at some spacial reasoning than women because we hunted more, maybe, but that very slight difference is a measure of how little practical, non-sexual, selective pressure their actually was.

            So based on what we know at the moment about the kind of intelligence that makes complex machines it seems likely that the resolution to Fermi's Paradox is that it is unbelievably rare. We may well be the only species to have such an intelligence in our galaxy, although even I have a hard time believing we're the only one in the universe. It could be, though.

        • by Ungrounded Lightning ( 62228 ) on Monday February 02, 2009 @04:36PM (#26699085) Journal

          The calculation of 1000 years seems a bit too long. We can't figure out how to shorten it because we don't know how long we're going to be using broadcast signal based communication as opposed to some other more direct means.

          My own contribution to the debate:

          As technology advances the limited amount of available bandwidth becomes more valuable, while costs of utilizing it drop. The civilization migrates its bandwidth use from simple, extremely redundant, coding schemes (like AM and FM) to subtle, highly-efficient schemes that are virtually indistinguishable from thermal noise (like OFDM). They also use spacial multiplexing to re-use the same bandwidth over and over at various locations. This buries the few redundant parts of the signal (like the pilot subchannels used for synchronizing the receiver) in interfering noise.

          The result is that, after a fairly short time, at a distance they are virtually indistinguishable from a hot black body - and lost in the sagans of other hot things in the galaxy.

          Our first AM voice radio broadcast was at the end of 1906. 102 years later we're taking a big step in the transition to OFDM-or-CDMA-everywhere by shutting down "analog TV" and replacing it with OFDM-based digital. AM and FM are already using digital variants to squeeze more out of their spectrum. Any bets on how long until they switch, too?

          Once the simple-modulation blowtorches are switched over the few remaining detectably-patterned signals will be soft voices crying in a wilderness of high-noise-floor. If we don't DELIBERATELY send some intended-to-be-noticed beacons we'll again be lost in the background - our own and the galaxy's.

          A thousand years? In our case the detectability sphere looks to be only a tad over 100 years deep.

          Don't blink!

    • Re:Solved? (Score:5, Interesting)

      by SatanicPuppy ( 611928 ) * <> on Monday February 02, 2009 @03:23PM (#26697949) Journal

      Maybe there really is no FTL, and other alien races are as leery of sending out giant seedships that they themselves can't ride in as we are, and are thus still hanging out in their home starsystem.

      Maybe aliens are everywhere, aware of us, and simply choosing not to communicate.

      Disproving aliens deductively is the opposite of science. The lack of easily obtained evidence for alien life is far from damning given the area that we are capable of observing with any real scrutiny.

      • Re: (Score:3, Insightful)

        by MutantEnemy ( 545783 )

        "other alien races are as leery of sending out giant seedships that they themselves can't ride in"

        But for this argument to work, you have to believe that every alien race declines to send out automated self-replicators.

        • Re: (Score:3, Insightful)

          Not at all. Think how many they'd have to send out. Think about the transit time, think about the number that would be lost. You can't really assume a straight geometric progression for something so incredibly fraught.

          For a civilization to be able to keep up that level of commitment for as long as it would take would be inconceivable. This isn't to say that it couldn't happen, but it is to say that it's damn unlikely, even by the standards of the universe.

          • Re:Solved? (Score:5, Informative)

            by AJWM ( 19027 ) on Monday February 02, 2009 @04:51PM (#26699321) Homepage

            Think about the transit time, think about the number that would be lost. You can't really assume a straight geometric progression for something so incredibly fraught.

            Well, almost, at least for the purposes of ballpark calculations.

            Now, we have to make a couple of assumptions -- such as that they have the technology to send out self-replicators that will last long enough to get to the next star, which is a function of speed and durability. For the sake of argument, let's assume that the Voyager spacecraft (which just left the Solar System) are capable of self-replication, have a very long-lived power supply (long half-life radioisotope, for example) and their electronics will survive long exposure to galactic cosmic rays. (All big assumptions, but imaginably within range of our technology.)

            Also assume an average spacing of about five light years apart for stars.

            At the current speed (about 16 km/sec), it would take a Voyager about 90,000 years to reach the next start. Allow 10,000 years for the laborious process of self-replicating from raw materials and launching another of itself on its way, for a total of 100,000 years per generation. Assume each vehicle replicates itself only twice, and stays put (perhaps assembling large black monoliths on the local planets for the mystification of any eventual inhabitants). So we have a doubling rate of once per 0.1 million years.

            Assume about 100 billion stars in our galaxy (this is the number I found most frequently mentioned), it would take between 36 and 37 doublings to send a probe to every star in the galaxy (less because stars are closer nearer the core). Call it 40 to allow for probe loss.

            So in a mere four million years, self-replicating probes travelling no faster than Voyager could visit every star in the galaxy -- except for the speed problem. That growth rate can be maintained initially, but like any spreading colony (such as bacteria in a petri dish) the edge of the colony can only advance at a certain speed, and the doubling rate has to fall off (it's ludicrous to think that the number of visited stars could go from half the galaxy to the whole galaxy in a mere 100,000 years, the probes would have to be approaching lightspeed for that).

            Take the galaxy diameter as 100,000 light years, it'd take nearly 2 billion years for a Voyager-speed probe to cross it, or near 3 billion to go around half the circumference (to avoid the black hole at the core). The galaxy is old enough that there probably sun-like stars (our Sun being a second-generation star, necessary if you want enough heavy elements for terrestrial planet formation) a couple of billion years older than ours. (And if we assume faster travel speed, say 0.01 c instead of 0.000055 c, the numbers get a lot better.)

            So Fermi's question was simply "where are they?". If they're really not around (vs simply ignoring us or being undetectable to us), then the above assumptions are too optimistic.

      • Re: (Score:3, Funny)

        by ByOhTek ( 1181381 )

        "Damnit, can't those monkeys from the Sol system just shut up?"
        "If we ignore them, they'll go away"
        "They've been shooting radio waves at us for decades, I think we've established they aren't going away..."

      • Re: (Score:3, Interesting)

        by oldspewey ( 1303305 )

        other alien races are as leery of sending out giant seedships that they themselves can't ride in as we are

        I don't think humans are particularly leery of the idea of getting on a starship. And even if 99% of humans have no interest in getting on a starship, that leaves ~70 million perfectly willing volunteers. Give it another few hundred years of technological advancement and we'll be able to contemplate something large enough to be a "generation ship", or place the travellers in suspended animation, or some other trick to make the lengthy trip survivable.

      • Re: (Score:3, Insightful)

        "Maybe aliens are everywhere, aware of us, and simply choosing not to communicate."

        I think this is most likely.
        To reach space you have lots of self-control so that you don't..uh..risk wiping out your civilization.

        Once you reach that point of sophistication, you would feel that we humans are so damn annoying, unpredictable and of little use that you would want to avoid us at all cost.

        That or we are an experiment they have been running for billion+ years and don't want to contaminate it. kinda like what we ea

        • Re: (Score:3, Funny)

          by Yvan256 ( 722131 )

          I don't know why, but I keep having this dream about "six times seven", whatever that means.

      • No FTL (Score:4, Insightful)

        by maillemaker ( 924053 ) on Monday February 02, 2009 @04:15PM (#26698735)

        >Maybe there really is no FTL, and other alien races are as leery of sending out giant
        >seedships that they themselves can't ride in as we are, and are thus still hanging out in their home starsystem.

        I'm sure I'm not alone in this, but I just had to say. If there really is no FTL, it is probably one of the most depressing aspects of existence.

    • Re:Solved? (Score:5, Insightful)

      by geminidomino ( 614729 ) * on Monday February 02, 2009 @03:28PM (#26698015) Journal

      "Paradox solved, right?"

      No. Some planets suitable for life have almost certainly existed in this galaxy for billions of years longer than the Earth. By now, one would expect there to have been civilisations that spread throughout the galaxy and therefore brought Earth within detection range of their signals...

      But they would have to be within earth's range in the last 100 years or so for them to detect us. "Billions of years" means they could have existed on Venus before humanity ever showed up, for all we know. If they were that close, the signals would have long since passed us by at the point we were discovering fire.

      Or they could have been reasonably nearby, but too far for the signal to reach us without fading out completely.

      Or they could be using a different form of communication than we are able to perceive.

      So, honestly, "expecting" anything is a little silly and assumes far too much.

    • Re:Solved? (Score:5, Interesting)

      by Ian Alexander ( 997430 ) on Monday February 02, 2009 @03:41PM (#26698201)
      Not necessarily. It may just be that interstellar travel isn't feasible, the ardent wishes of sci-fi writers everywhere notwithstanding. Remember, it's never enough to simply be able to do something: it has to make economic sense if you expect to get anybody else on board, too.

      Assuming you can't skirt around the light barrier then that basically means sending small groups of people (or aliens or whatever) across trillions of miles, probably in some kind of hibernated state, in the hope that they'll bump into a habitable somewhere, set up shop, and begin to populate. Any returns on investment will be very intangible indeed- physical goods have to come back the same way they came (meaning it would have to be extraordinarily valuable to merit the shipping and handling on an interstellar ark) and information is cheap. You'd need to expect a very valuable treasure-trove of knowledge indeed for information to start making sense as an expected ROI.

      I know many people just assume that interstellar travel is the "next step" in the development of societies but the longer I look at it the less it seems to offer tangible benefits for the people who have to invest in this.

      I expect a society thinking in the long-term would obviously see the benefits of spreading one's seed across multiple star systems... but you have to postulate the existence of a society that takes the long view. Considering how easily a society as advanced as ours (not saying we're very advanced: just a society at the same level of advancement as us) is busily undermining its own biome, knows it's doing it, and doesn't care, and took pains to smother other societies which might have taken the longer view, I don't think we should expect many societies to reach the "long-view" stage before they wiped themselves out or got wiped out.
      • Re: (Score:3, Interesting)

        by Jerf ( 17166 )

        Assuming you can't skirt around the light barrier then that basically means sending small groups of people (or aliens or whatever) across trillions of miles, probably in some kind of hibernated state, in the hope that they'll bump into a habitable somewhere, set up shop, and begin to populate.

        That is a grotesquely 20th century view of interstellar colonization. It may or may not be on the edge of feasibility with fusion-based propulsion, it probably is with implausible anti-matter propulsion, but it's quite

  • by gpronger ( 1142181 ) on Monday February 02, 2009 @03:09PM (#26697735) Journal
    One of the thoughts that's crossed my mind as we further explore and understand utilization of quantum information is that if there is sentient beings "Out There" with some level of capability for space exploration is that it would seem that this would be a very likely way for them to maintain communication. Efforts such as SETI would then be attempting to discover background noise (I use the term "noise" here more as commentary on what most of what we communicate tends to be) of civilizations no more advanced than ourselves attempting only very nearby levels of communication.

    Civilizations capable of greater levels of exploration would likely have developed means of utilizing communication along the lines of quantum information than our radio waves.
  • by Anonymous Coward on Monday February 02, 2009 @03:10PM (#26697747)

    I thought it was because as they reach our level of civilisation, they built giant particle accelerators for research and turned their planets into black holes.

  • The First Ones (Score:5, Insightful)

    by starglider29a ( 719559 ) on Monday February 02, 2009 @03:10PM (#26697757)
    Maybe we are the first to achieve this capability. If life did create itself from a universe that created itself, ONE of the life forms which achieved this interstellar communication would have to be first. Why not us?
    • by sakdoctor ( 1087155 ) on Monday February 02, 2009 @03:13PM (#26697779) Homepage


    • Re:The First Ones (Score:5, Insightful)

      by SatanicPuppy ( 611928 ) * <> on Monday February 02, 2009 @03:19PM (#26697877) Journal

      Maybe a zillion races have achieved the capability at roughly the same time, and are just more than 100 light years away from us.

      What are the odds of anyone picking up our broadcast noise anyhow? It's not like we're aiming high wattage transmissions directly at likely stars, and with the transition to digital, our signal becomes even more ellusive (smaller spectrum footprint).

      It's just as likely that other races only went through a brief period of wideband, and then switched to wired or line of sight optical or quantum bits or some crap we haven't even thought of yet.

      The whole paradox is the height of hubris: aliens have to be like us, they have to advance along the same technological track, and they have to be broadcasting on a scale that we can easily pick up...We haven't cataloged every star yet, and that's an order of magnitude over any artificial broadcast we can understand.

      • Re: (Score:3, Insightful)

        by ptbarnett ( 159784 )

        It's not like we're aiming high wattage transmissions directly at likely stars [....]

        Actually, we have: []

        It was a one-time occurrence, and the stars it was aimed at won't even be there when the message arrives.

        However, Arecibo has also been used for Radar Astronomy [], to map nearby planets. Those transmissions were probably powerful enough to detect outside our solar system.

    • Re:The First Ones (Score:4, Interesting)

      by jmichaelg ( 148257 ) on Monday February 02, 2009 @03:26PM (#26697985) Journal

      Though it's possible we are the first, it's as likely as winning the lottery. Someone has to do it but the chance of that someone being you is so small that you should first rule out other, more plausible, scenarios.

      My favorite is that only the paranoid survive. Civilizations that learn to communicate quietly are the ones that survive. Broadcasting your existence is a great way of advertising 'livable real estate here!' and inviting other civilizations over for a look see. Not too smart if it turns out they end up wanting your planet.

  • by Dr. Manhattan ( 29720 ) <> on Monday February 02, 2009 @03:11PM (#26697765) Homepage means that civilizations that spread out and last longer than 1K years are exceedingly rare. Which would mean that our odds of achieving any meaningful interstellar travel are quite low. (We might make a space probe or two, but like how we got to the moon but haven't done anything with it, apparently nobody puts out space colonies.) There are other posible theories, though [].
    • Re: (Score:3, Interesting)

      by starburst ( 63061 )

      I posted this in January 2005:

      Drakes formula allows some kind of estimate as to the number of intelligent societies there might be "out there".

      The following is from a great book by A.K. Dewdney: Yes, We Have no Neutrons.

      The formula is N = R* x Fp x Ne x Fl x Fi x Fc x L

      For which:
      R* = number of new stars that form in our galaxy each year
      Fp = fraction of stars having planetary systems
      Ne = average number of life-supporting planets per star
      Fl = fraction of those planets on which life develops
      Fi = fraction of li

  • by SatanicPuppy ( 611928 ) * <> on Monday February 02, 2009 @03:12PM (#26697769) Journal

    This is hardly a new idea. It's so not new that I think I remember saying something similar about two years ago [], and I'm not exactly an expert.

    Analog signals degrade quickly, and digital signals are worse, in their way, because they don't tolerate degrading as well. Couple that with broadcast limitations imposed by local governments to keep signal strength down, and I can't see how our signal could be reliably detected more than a few light years away without a HUGE radio antenna array.

  • by Anonymous Coward on Monday February 02, 2009 @03:14PM (#26697801)

    The scope of the Fermi Paradox deals with the length of time it would take an intelligent civilization to explore and colonize the galaxy, and given Fermi's estimates we should have observed spacecraft and/or probes. SETI's signal hunting doesn't even scratch the surface of the paradox.

  • by rwalker429 ( 1452827 ) on Monday February 02, 2009 @03:15PM (#26697813)
    The real answer is that they've been trying to communicate with us for years but RIAA, fearing they might play music for us has already had their ISPs throttle their messages into oblivion.
  • by gzipped_tar ( 1151931 ) on Monday February 02, 2009 @03:18PM (#26697863) Journal

    We humans are still a bunch of young, angsty teenagers. We desperately want to make the "first contact", crying and yelling and suffering from the depressive thought of loneliness.

    Other galactic civilizations simply matured and stopped worrying about such pointless things. They make themselves busy with real business.

    Grow up, humans.

  • Communcations (Score:3, Insightful)

    by TechwoIf ( 1004763 ) on Monday February 02, 2009 @03:19PM (#26697879) Homepage
    What about new type of commutations that we have not invented yet? Its possible they are communicating all over the place but we can't hear them yet because we don't have the technology to hear them yet.
  • Mistake in summary (Score:3, Interesting)

    by bbasgen ( 165297 ) on Monday February 02, 2009 @03:20PM (#26697883) Homepage
    Summary says: "300 communicating civilizations in the Milky Way". The quote is: "300 communicating civilization in the galactic neighborhood". I interpret the latter to mean all solar systems within 1,000 light years. The former quote leads to the entire milky way, which has a diameter of 100,000 light years.
  • intellgient life... (Score:3, Interesting)

    by goffster ( 1104287 ) on Monday February 02, 2009 @03:21PM (#26697899)

    Suppose intelligent life was a super freakish accident, not a forgone conclusion. It took 4-billion years for it to develop on earth. I'll bet it might easily have never happened. And then, there was no reason why we had to develop a technology based culture. That, in itself, might have been a freakish cultural event.

    So, maybe, we are pretty special after all.

    • by GodfatherofSoul ( 174979 ) on Monday February 02, 2009 @03:43PM (#26698239)

      Except that intelligence doesn't necessarily take 4 billion years to evolve. It's not a nice, clean timeline. The real hurdles were evolutionary events like the spark of life, sexual reproduction (leading to more mutations), and multi-celled organisms. Evolution, through nature's nasty tendency to wipe the slate clean, has to keep taking steps backwards. Dinosaurs lost their place on top of the heap after 100s of millions of years of dominance and 65 million years later we have intelligent life.

      Imagine if there are worlds where there are fewer extinction level events or environmental factors that favor jumping the hurdles sooner. We just don't know enough about other planets to know how long it takes for intelligence to evolve.

      • by scorp1us ( 235526 ) on Monday February 02, 2009 @04:37PM (#26699103) Journal

        Good points, to which I want to add, that intelligence does not necessarily lead to radio waves at any eventual point.

        Radiowaves are a social phenomenon. They are used to communicate between beings of shared language over large distances in short amounts of time. This means that there is a need to communicate quickly, and natural methods are insufficient. For example, whales are intelligent and communicate over great distances. Yet they have no need for radios because the water medium is good enough for their needs.

        Animals are capable of using magnetism to coordinate. Be it distance migrations or short-distance homing. Avian/IP takes this into consideration. If they found a way to communicate naturally via the magnetic material in their heads (over short distances - telepathy) they could pony express a message throughout their habitat at relatively low time cost.

        Then even if they had the motivation or understanding they still need to be physiologically equipped to construct a device. And that device needs mining and metal refining technologies.

        So while there may me the means, there may not be the motivation for the mega an giga-watt broadcasts we currently use.

        I expect that if we ever get exploring other habitable worlds, we'll find a lot of life to interact with in complex ways, but are technologically inferior due to physiology. I call this the "cephalopod argument". That is, they seem to be relatively intelligent creatures, while sharing little to nothing in common with our nervous system. They've been unchanged for millions of years, without additional evolutionary selection criteria, they have no reason to change. (Also, until we can communicate with them we are unlikely to be able to communicate with ETs unless they provide the means)

  • by ZombieRoboNinja ( 905329 ) on Monday February 02, 2009 @03:24PM (#26697959)

    Unless it's been vastly misrepresented in mainstream presentation (like TFS), Fermi's Paradox sounds pretty ridiculously simplistic.

    Other bad assumptions it makes, just off the top of my head:

    1. Other intelligent civilizations want to engage communications with aliens who, for all they know, might try to blow them up or eat them.

    2. Those civilizations are willing to spend resources to beam electromagnetic radiation out into space in the vague hope of someone noticing.

    3. Other intelligent civilizations "capable" of "communication" will follow the same technological arc as us and develop electromagnetic communications rather than, say, quantum communications or something we haven't even thought of yet.

    4. Those aliens will assume that WE (or some unknown aliens) will be listening carefully for extrasolar broadcasts.

    5. Those aliens even have a concept of "communication" and aren't just some hive-mind that never needed to evolve social skills.

    6. They didn't cut their Alien-SETI funding to pay for medical research or an Alien-Wall-Street bailout package or something. (I mean, what do you think the chances are that WE will broadcast for a thousand years?)

    And so on.

    Really, Fermi's Paradox sounds like me saying that if I sit on a lonely beach for a week and don't find a bottle with a message in it in proper English, there are no other intelligent beings in the world.

  • by kmahan ( 80459 ) on Monday February 02, 2009 @03:31PM (#26698049)

    It's not like we're located close to Downtown Galaxy. We live out on the edge. There's probably some galactic equivalent of AT&T or Comcast that is telling everyone else "We'll be providing them with service 'soon'. So our monopoly is justified."

    Either that or the installer showed up and we were too busy/unaware to answer the door. So they said they'd be back later.

  • by Animats ( 122034 ) on Monday February 02, 2009 @03:33PM (#26698079) Homepage
    • Current SETI work assumes that someone is specifically sending a "carrier" at us, an RF signal with a constant frequency. That's 1930s technology. No modern transmission system has a strong "carrier"; they all look like noise unless you can figure out the decoding. An advanced civilization may assume that anybody worth talking to has antennas the size of moons, picks up all RF that comes through its solar system, and figures out anything interesting. We're not there yet.
    • Maybe technological civilizations don't last that long. Recorded human history is about 3000 years, but industrial civilization is only 200 years old. (The first railroad ticket was sold in 1808; that's a good starting point for deployed industrial technology.) Already, we're starting to run out of natural resources.
  • by caywen ( 942955 ) on Monday February 02, 2009 @04:10PM (#26698643)
    It's possible that our technological advances will sufficiently alter our thinking to the point that the question of ET's will fade away to the point of being boring and moot. It sounds silly, but what if, for example, we discover that there is a God, and we get his telephone number the next morning? Speculative, but perhaps other civilizations simply transcend their curiosity at some point well before they travel beyond that horizon.
  • by jandrese ( 485 ) <> on Monday February 02, 2009 @04:25PM (#26698897) Homepage Journal
    Ultimately, the problem I have with the SETI project is that they're looking for signals that by nature will have to suffer lightyears of Free-Space Path Loss [] (In short: it's proportional to the square of the distance). Worse, since we assume such alien civilizations will be hanging out near a star for the most part (deep space is cold and lacking in resources), you have a gigantic open fusion reaction happening right behind your signal, raising the noise floor tremendously.

    From a layman's perspective, I don't see how they could reasonably hope to see anything, especially if the aliens are like us and tend to direct their transmitted energy rather tightly to avoid wasting too much of it.

    Lets say for instance that we can pick up a signal from Geosync Earth orbit using little more than a crappy whip antenna (See: Satellite radio) for a system with maybe 200dB gain in total. Now lets say we're looking for ET with a magical system that has a million dB worth of gain. The distance from the Earth to a Geo satellite is 26,200 miles. The distance from the Earth to Alpha Centauri is 2.57 Ã-- 10^13 miles. Just comparing the square of the distances (6.86 x 10^6 to 6.5536 Ã-- 10^26), you can see that a gain of 10^9 is just not going to cut it, not by a long shot.

    It seems to me that the only way SETI could possibly work is if ET was narrow beaming an extremely powerful signal directly at Earth 24/7 for centuries, or if they were hanging out in orbit chatting away over CB radios in stealth spaceships. The most plausible reason why SETI has not found anything is that any signals that are out there are well below are detection threshold, and this is even before we begin to think about a civilization that moves beyond RF transmissions in favor of something more exotic (entangled photon radios?).
  • Keep in mind (Score:3, Insightful)

    by blueg3 ( 192743 ) on Monday February 02, 2009 @04:32PM (#26699017)

    Note the following:
    1) Author is an MBA. The "Bouchet-Franklin Institute" is his private lab.
    2) The place of publication, arXiv, while very useful in certain fields of physics, is not peer-reviewed. It's basically the same as posting this paper on your blog.
    3) The arXivblog, not run by any people actually associated with arXiv (as far as I can tell) regularly posts completely inaccurate summaries.
    4) The published paper is laughably simplistic. As others have pointed out, these are obvious considerations, and the paper is mostly argument and simple geometry. While it's nice to see some back-of-the-envelope calculations on a minimum civilization density for a given detection cutoff, that's exactly what this is -- back-of-the-envelope calculations.

  • by Shotgun ( 30919 ) on Monday February 02, 2009 @04:42PM (#26699167)

    Hell, man! Is there any intelligence down HERE!!

    Jeesh! These scientist with all their assumptions and preconceptions. Last week, we were supposed to believe that because we're able to capture a few pixels of UV radiation from a distant star system, and it can be spun into a computer model of the planet's atmosphere. The whole thing is a bunch of naval gazing to keep a bunch of nerds a colleges employed. Get a job, guys.

If graphics hackers are so smart, why can't they get the bugs out of fresh paint?