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Science

SETI@Home Revisits Its 100 Best Signals 344

Posted by Hemos from the one-from-the-vaults dept.
cmbrothe writes "The Planetary Society is running an article about SETI@Home's plan to revisit its 100 most promising signal candidates. The article also outlines the criteria for selecting the candidates."
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SETI@Home Revisits Its 100 Best Signals More

SETI@Home Revisits Its 100 Best Signals

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  • the criteria... (Score:5, Funny)

    by jaredcoleman ( 616268 ) on Thursday December 05, 2002 @11:36AM (#4818398)

    the signal must sound like a humpback whale...

  • The problem with doing it this way (Score:5, Funny)

    by Transient0 ( 175617 ) on Thursday December 05, 2002 @11:37AM (#4818404) Homepage
    Is that the REAL signals will obviously be coming from starships in nearby space which have either warp/hyperdrive and will therefore be NOWHERE near where they were when the signal was first detectred months or years ago.
    • except of course if the signal went through a space anomaly that we havent encountered before..

      Read your Star Fleet manual ensign!
    • However, you are overlooking the fact that signals broadcasted while travelling at warp speed retain warp characteristics for about 0.5 seconds after transmission which would allow the signal to arrive exactly 23.7 hours before the ships arrival assuming it is headed towards Earth. If it has another destination, the calculation will naturally get a little more complicated.
  • 'First, the least reliable signals must be weeded out in a process called "data integrity check", and those that are most likely the result of detection or computer error are eliminated' So they're going to throw out all of the signals that were a result of detection. Hmmm...

  • formula for likelihood of life (Score:5, Insightful)

    by guidobot ( 526671 ) on Thursday December 05, 2002 @11:39AM (#4818419)
    The formula used to rank the different stars according to the likelihood that they would host a communicating civilization is:

    score= N*(bv-bv0)*exp(0.5*(bv-bv_sun)^2)/(par+0.01)^3

    where

    N is a normalizing factor, 1.65x10^7
    bv is b-v color
    bv0 is b-v color of the bluest star in the catalog (-0.41)
    bv_sun is the b-v color of the sun (+0.65)
    par is the parallax in milliarcseconds

    How exactly do you test the validity of a formula like this?

    • Re:formula for likelihood of life (Score:5, Funny)

      by ari_j ( 90255 ) on Thursday December 05, 2002 @11:45AM (#4818465)
      Empirically. You find places that it says there is life. Then, you go and check for life. The correlation ratio between the two sets of results should give a very good indication of the validity of said formula.

    • score= N*(bv-bv0)*exp(0.5*(bv-bv_sun)^2)/(par+0.01)^3

      How exactly do you test the validity of a formula like this?

      That's easy -- it's clearly wrong. It's saying the Sun gets the lowest possible score according to the 3rd factor, when it should obviously get the highest score. (They left out a negative sign.)

      Why do journalists put formulas online when they don't have a clue what they mean?
      • >> That's easy -- it's clearly wrong. It's saying the Sun gets the lowest possible score according to the 3rd factor, when it should obviously get the highest score.

        There's no life on the Sun, ya goofball!

      • Maybe we were't clear, low scores are better. (I didn't have a chance to review Amir's article before it went out. In fact, I haven't read it yet. Does that mean I'm a real slashdotter?)

        When you get down to it this "star score" is fairly arbitrary. I outght to know, I invented it. If you take out the Gaussian term, it reduces to the number of stars in our sample closer to the sun than the star being scored that are also bluer than the star being scored.

        I threw in the Gaussian term as a "we like stars like the sun" term.

        But it's OK for this "star score" to be somewhat arbitrary. The "star score" represents how interesting the star is to us, not a literal interpretation of the probability of life existing around that star. A "how probable is life there" score doesn't really exist.

    • It's just a operational formula. You've gotta start somewhere, you know!

      I tried to dig up the paper, but these guys are really publishing a lot of stuff. this [harvard.edu] may have something to do with it. The author's homepage is here [berkeley.edu], you can look through a list of some of his papers.

    • How exactly do you test the validity of a formula like this?

      I assume you would test it by examining a large number of star systems for signs of life. Since we have only one firm data point (our Solar System) there has to be a lot of handwaving. The formula is designed to weight more heavily stars similar to our own (though there seems to be a copy error in the exponential factor--a negation has been lost and it actually weights for stars that are least like the sun.)

      The first factor penalizes young, short-lived, blue stars.

      The parallax term seems to bias the score in terms of more distant stars--again, this might be a typo.

      The formula is just a tool to aid SETI@Home astronomers decide which stars are more likely to bear life, since they can't investigate all of them. It's a guess, nothing more.

  • 5 Billion? (Score:2, Insightful)

    by redfiche ( 621966 )
    Five billion candidates? Seems to me like they should have weeded some of those out along the way. Wasn't that the point of getting all that computational power, to come up with a manageable sample of promising possibilities?

  • Playing the Odds (Score:4, Interesting)

    by Nintendork ( 411169 ) on Thursday December 05, 2002 @11:41AM (#4818436) Homepage
    I'm telling myself that it's not going to happen, but what if more than one of those 100 candidates turns out to be the real thing. What a shocker that would be!

    I mean, with the amount of planets out there, I'm sure there's a whole lot of life and a lot of intelligent life. It's just that we hope to find one other intelligent race and people aren't even thinking about finding more than that.

    -Lucas

    • As an afterthought on the possibility of intelligent life, think about this. There was life on Mars. They're thinking there might be life on Europa. That's 3 different bodies producing life (Found thus far) in our solar system alone.

      -Lucas

    • the message would probably say something along the lines of... "first post!", or "hello world!...?"

    • would be that life isn't rare. Therefore, we don't have to treat the Earth carefully, because our situation isn't unique. Clear-cut those rainforests, slash-and-burn agriculture is best; pollution controls - we don't need no steenking pollution controls; biodiversity is for weenies.

      Oops, *how* far away did you say these other planets are? :-) :-) :-) (because sometimes sarcasm/humor goes unrecognized)
      • Sometimes, I read that Carl Sagan quote on the poster showing Earth as a tiny little dot. I then think about how stupid it is to worry about our planet. I mean, on the galactic scale, does it really matter?



        But then I think about how someday I'll want kids. I would want them to grow up in a beautiful world. I'm sure they will experience the same thing and that desire will carry on every generation. That's when I settle the thoughts of raping the forests, destroying ocean life, and getting a 6 lb. supercharger for my Z28.

    • Re:Playing the Odds (Score:3, Insightful)

      by C14L ( 622656 )

      I'm telling myself that it's not going to happen, but what if more than one of those 100 candidates turns out to be the real thing. What a shocker that would be!

      In fact, that could be quite beneficial for humanity. Humans tent to identify themselfs by what they not are. In other words: If a group of people has some kind of "enemy" or "opposite", it usualy becomes more united. That does allways happen and on any scale. So hopefully, when we discover extraterrestial civilizations, people may begin to define themselfs more as "humans" and less than citizens of different countries.

      Thinking that over... if they don't find any signal, they should make up one! Anyways, nobody will be able to validate it, if it comes from some 1000 Lightyears away...

  • /me crosses fingers that my packet detected ET

    would i get modded up for that?

  • Wait a minute.... (Score:4, Funny)

    by John Harrison ( 223649 ) <johnharrison@@@gmail...com> on Thursday December 05, 2002 @11:43AM (#4818448) Homepage Journal
    Wasn't that telescope destroyed in Goldeneye? How are they still using it?

  • I have to wonder... (Score:3, Funny)

    by craenor ( 623901 ) on Thursday December 05, 2002 @11:43AM (#4818452) Homepage
    If they've done any research to correlate the number of possible signals to the frequency of radio broadcasts featuring Michael Jackson...just a thought, I mean, they are looking for aliens...

  • The "Wow" Signal (Score:5, Informative)

    by szquirrel ( 140575 ) on Thursday December 05, 2002 @11:44AM (#4818461) Homepage
    Just for fun, I googled the 1977 "Wow" signal mentioned in the article and every so often in SETI news. Found this good BBC article [bbc.co.uk] on the subject.

    This blatant karma whoring is brought to you by the letters "ET".
  • The day that SETI searches for signals might be one of the most important dates in mans history J

    This is because we might actually find a CONFIRMED signal of intelligent life!

    But it most probably will be nothing (the chances of us getting a hit see slim to none based on the probability )

    • Sorry... No. (Score:3, Interesting)

      by SaturnTim ( 445813 )

      Sure, if the SETI project gave conclusive proof that there was alien life, It would be a day that would go down in history.

      But, it has to be rock solid proof. Not just a signal, we need a communication from another world. Otherwise CNN will have someone on there within the hour making up 50 other possibilities for the signal.

      --ST

  • Obligatory comments here...

    • From the religious right, about how there are no aliens, and if there are, they are the work of Satan.
    • From the ignorant masses, about how this is a waste of money that could be better spent on (Insert pet project here).
    • From the biologists, about CPU cycles that could have been spent finding a cure for cancer.
    • From the Optical SETI folks, about what a waste of time RADIO SETI is.
    • From the /. crew about "Isn't this a dupe?"

    Did I miss any?

  • Would they detect themselves? (Score:5, Interesting)

    by wowbagger ( 69688 ) on Thursday December 05, 2002 @11:47AM (#4818477) Homepage Journal
    While I am a contributor to SETI@home, I have to wonder about the following question:
    "Given the rules they place on a signal, would SETI@Home have detected the past attempts we've made to contact other stars?"


    Consider the past efforts at Arecibo to send a message to other stars. We focused on one star for a couple of hours, and sent a message. Perhaps we repeated it over the course of a few days.

    Now, let us suppose that a civilization with a similar technology to ours was located on a planet around Proxima Centauri, and let us suppose they did exactly as we did in our transmissions at Arecibo. Would that signal have been found by SETI@Home?

    Given how the SETI receivers might not have been looking in the right places at the right times to see more than one transmission, might that signal have been discarded because we did not see more than one instance of it?
    • Now, let us suppose that a civilization with a similar technology to ours was located on a planet around Proxima Centauri, and let us suppose they did exactly as we did in our transmissions at Arecibo. Would that signal have been found by SETI@Home?

      SETI isn't looking for a person-to-person call necessarily, just for some scrap of evidence of intelligent life. By that criteria our planet has been spewing out transmissions like crazy for the last 70 years or so. If we find someting like that, then we at least know where to start looking for a "Hello, World!", or where to start sending our own.
      • I don't think SETI is sensitive enough to pick up TV signals from even
        the nearest stars.

        To pick up their TV signals, I think we need a dedicated SETI radio
        telescope on the far side of the moon - something a couple of hundred
        miles across maybe.

        So we are listening for a definite "Hello Earthlings!"
        type of signal from a pretty powerful transmitter. Something
        containing the prime numbers, the first 100 binary digits of PI,
        something like that.

        My question is whether any aliens would send such a signal. You'd
        be taking one heck of a chance that it won't get picked up by more
        advanced civilisations with a penchant for destroying upstart
        planets.

        It seems to me that most civilisations will be sitting - quietly
        listening just like we are.
    • Ever since the invention of radio, modulated beams of EM radiation have escaped our atmosphere in all directions. If you had a high gain YAGI antenna on Alpha Centauri III, you would be watching the the August 1997 re-run of Star Trek: TNG, "parallels". In a year or so you'll be tuned in to the gripping election programming from Futurama, and finding out that Richard Nixons head is president of Earth.

      Live just under 60 ly away? You'll no doubt be hearing tails of DDay being a tremendous success as the BBC world service waves hit you.

      Thats the signals we are looking for.

  • Window of contact (Score:4, Insightful)

    by hpeg ( 585118 ) on Thursday December 05, 2002 @11:49AM (#4818493)

    I can't believe that people are still looking for signs of extraterrestrial intelligence, hooing to make contact one day.

    Stanislaw Lem once described the window of contact as the tiny amount of time in a planet's life that an intelligent life form has to evolve far enough to create enough noise around their planet that will be picked up as non-static background noise, until its civilisation dies the entroy death.

    Even if we picked up something now, it would only be a tiny flicker of something that existed millions of years ago, with no hope of us ever meeting whoever created this glimpse of order in the chaos of the universe.

    We are alone out there. Confined by the same rules that hold our universe together into a tiny section of space and time. The best we can hope for is to become nomads, travelling to near systems in the hope of making them inhabitable when this sun gives out. If we haven't fallen into the ashes until then.

    • Re:Window of contact (Score:3, Interesting)

      by Izeickl ( 529058 )
      Your opinions are just that, opinions and speculation. Your view is no more valid than that of someone who thinks there is some alien life millions of light years away. Unfortunatly neither arguments can be proven, at least not yet. I would like to think there are other life forms out there, but im not commiting myself to one side or the other as no one knows! As Tommy Lee Jones in MIB said few hundred years ago everyone was -certain- the earth was flat, the earth was centre of the universe etc etc...
    • Even if we picked up something now, it would only be a tiny flicker of something that existed millions of years ago...

      The closest star to Earth is only 4 light years distant. Isn't it at least remotely possible that a detected intelligence would be somewhere nearby rather than millions of light years away?

    • Re:Window of contact (Score:2, Insightful)

      by Justify ( 33053 )
      Sounds fair.

      Now, lets think about the problem from another approach. Using current/existing scientific beliefs to restrict scientific dreaming/entreprenurship is useful and proper some times and found to be inaccurate other times. I would say three things can happen by going against that braking effect:
      1) the people involved waste their time and money, and no results can be concluded.
      2) the original scientific beliefs are proved more thoroughly.
      3) the original scientific beliefs are proved inaccurate, and new ideas and beliefs are available.

      I would also say that persons in the field of R&D are not so concerned about 1 and 2. 3 is their major motivating factor, and they do the best they can with what they've got. If they have a dream, then that only helps them work.

      So, in summary, I'd say that since your point is valid, that those people interested in doing this research need to weigh their dream with existing scientific beliefs. ..and then spend their time doing what they choose to be doing. Balance.

      Just opinions.

    • Re:Window of contact (Score:5, Insightful)

      by mmacdona86 ( 524915 ) on Thursday December 05, 2002 @01:06PM (#4819166)
      As others have pointed out, we could pick up something that existed a few score or a few hundred years ago, and that would certainly be interesting.

      Even knowing there was intelligent life somewhere else millions of years ago--and if the signal was millions of years old, it would necessarily represent an extremely advanced civilization, powerful enough to transmit a signal to another galaxy--would be extremely interesting scientifically and philosophically.

      Finally, it is only conjecture that the "Window of Contact" is brief. For all we know, once civilizations get to a certain point of development, they last forever, and slowly but surely colonize all the inhabitable parts of their galaxy.

    • Re:Window of contact (Score:3, Interesting)

      by sbaker ( 47485 )
      There are two aspects to this:

      1) Will the shortness of the lives of civilisations reduce the
      probability of our detecting a message by so much that we won't
      ever see one?

      2) If we recieve a signal from a long dead civilisation - then
      how will we ever talk with them?

      In response to (1): The Drake equation (which estimates the number
      of alien civilisations that ought to be out there) takes this into
      account - and taking our best guess at that number, we should still
      expect to see a significant number of civilisations out there at the
      right stage in their life-span to talk to us. Of course there are a
      huge number of wild-ass-guesses in that equation - so making any
      concrete statements about the result is dangerous.

      However we can never know what the typical lifespan of a civilisation
      is - because the only planetary civilisation we have any data on hasn't
      died out yet!

      In response to (2), I have to say that if we could ONLY detect signals
      from long-dead civilisations, it would still be worth listening.

      Firstly because the mere knowledge of the existance of intelligent
      life elsewhere in the universe would justify the search.

      Secondly, it's also possible that the transmission would include the
      entire Encyclopedia Galactica - so even though the civilisation is
      dead, it might pass on knowledge that would pay for SETI a million
      times over.

      So, whilst the shortness of the lifespan of civilisations is a concern,
      it's not a reason not to search.
  • Short-lived stars, whose lifespan is only a few million years, are also excluded from consideration, since complex life would not have had time to evolve in such an environment.

    But what about the Genesis Project? That planet came to life in just a few short years. Oh what horror to think that the reborn Spock might be left behind!

  • Is this really realistic? (Score:2, Insightful)

    by Anonymous Coward
    Almost all celestial signals vary in frequency over time. That is because they originate on moving celestial bodies, whose velocity relative to the Earth changes constantly. This causes the signal's detection frequency on Earth to vary as well, in a phenomenon known as "Doppler drift." ... If, however, the barycentric frequency of a signal remains steady, this almost certainly means that it is designed to compensate for the movements of its own host planet. In other words, it would point to a deliberate intelligent design.

    While this is as good a plan as any, i suppose, given the find-a-possibly-nonexistent-light-switch-in-the-da rk goals of the SETI project, would this really have any chance of hitting anything?

    I mean.. why would an intelligence compensate for doppler shift? The only reason i can think of that they would is if they were trying to beam "hello out there" signals into outer space. Do *we* (i.e. humans) compensate for doppler shift when we broadcast those random signals into space trying to find aliens? Or are they hoping to find interstellar communications between an alien race and its own starships?

    And anyway, would this really work? I mean, everything in the universe is moving away from each other, but they're all doing it at different speeds. One would think that the signal the aliens put out would have to be specifically targeted at earth itself in order for its frequency to stay constant, if the signal was targeted at something else the frequency wouldn't drift at quite the right rate (assuming the way you compensate for doppler shift is, in fact, to vary your frequency) to be constant from earth.

    Is any of this right?
    • I mean.. why would an intelligence compensate for doppler shift?

      If they are trying to make the signal stand out and shout "I'm intelligent" then yes.

      The only reason i can think of that they would is if they were trying to beam "hello out there" signals into outer space.

      That's a good reason for doing it.

      Do *we* (i.e. humans) compensate for doppler shift when we broadcast those random signals into space trying to find aliens?

      To my knowledge, nobody regularly and deliberately broadcasts into space so that some space aliens can pick it up. I can only remember it being done a couple of times for publicity purposes and I doubt anybody bothered to adjust the signals for doppler shift.

      If our planet is a good model then the chances of finding another plant deliberaterly transmitting a signal so that it can be picked up by another planet are slim. However, if you are going to transmit, then sending a barycentric signal will make it stand out from all the other natural radio signals and say "I'm intelligent".

      Or are they hoping to find interstellar communications between an alien race and its own starships?

      I see that as being unlikely.

      if the signal was targeted at something else the frequency wouldn't drift at quite the right rate (assuming the way you compensate for doppler shift is, in fact, to vary your frequency) to be constant from earth.

      If they transmit their signal so that it is barycentric to their solar system and we correct the signals that we receive so that they are barycentric to our solar system then there will be no doppler shift due to planet rotation or motion around the sun. There will still be a doppler shift due to the relative motion of our solar system to their solar system but this is likely to only change very very slowly (and changes are what is important) and be of orders of magnitude smaller than a non corrected signal.

  • Number One on the SETI "Top 100" Hit Parade: (Score:5, Funny)

    by DuckDuckBOOM! ( 535473 ) on Thursday December 05, 2002 @11:50AM (#4818505)
    A cover of "Peppermint Twist" recieved from a point near Epsilon Eridani, played on what sounds like oil drums and unlubricated condoms using a 68-tone scale. Great beat and you can dance to it if you have five legs.
    • Hope not --- Eps Eri is too young to have much in the way of a planetary system (although at least one planet orbits it), let alone any evolved life.

      I suppose you could have the equivalent of stellar system "camping" - hopping around from place to place and sending out signals...

  • Are we broadcasting, too? (Score:4, Interesting)

    by Seanasy ( 21730 ) on Thursday December 05, 2002 @11:55AM (#4818532)

    I'm not talking about all the regular satellite communications. Are we intentionally broadcasting any messages for the universe at large?

    If, however, the barycentric frequency of a signal remains steady, this almost certainly means that it is designed to compensate for the movements of its own host planet. In other words, it would point to a deliberate intelligent design.

    And would regular satellite communications appear barycentric? It doesn't sound like it. So, if we're not broadcasting barycentric signals, why would we expect other lifeforms to broadcast them? Or are we braodcasting something barycentric? Can I tune in?

    • I'm not talking about all the regular satellite communications. Are we intentionally broadcasting any messages for the universe at large?

      Short answer is no - apart from at least one PR message sent out from Aricebo in the 70's IIRC.

      And would regular satellite communications appear barycentric? It doesn't sound like it. So, if we're not broadcasting barycentric signals, why would we expect other lifeforms to broadcast them? Or are we braodcasting something barycentric?

      The current SETI efforts assume that we will be receiving signals from a beacon aimed at least generally in our direction and which will be very high power. This is obviously a big assumption, but the problem is that we don't have the technology at the moment to detect "alien TV"-strength signals. Those signals would be utterly missed by the Aricebo effort, as they are too weak to resolve against the background noise. The Square Kilometer Array [usska.org] radio telescope might be able to pick up alien TV signals out to a dozen or so light years.

    • Or are we braodcasting something barycentric? Can I tune in?

      Yeah, we are - but you don't want to tune in [manilow.com].

    • Re:Are we broadcasting, too? (Score:4, Interesting)

      by Idarubicin ( 579475 ) on Thursday December 05, 2002 @01:09PM (#4819188) Journal
      It's not that SETI@Home is ignoring non-barycentric signals; they are just assigning barycentric signals a higher priority for examination.

      This is a pretty reasonable approach, actually. Barycentric signals imply deliberate action. Further, they imply that the signals are intended to be received by someone or something (not necessarily us) beyond the immediate space about the transmitting planet.

      SETI@Home is certainly not ignoring non-barycentric signals, they are only prioritizing the (literally) billions of potential 'hits' they have accumulated. I'm quite sure that if we started seeing large gaussians every time Arecibo swung past Proxima Centauri, nobody would ignore them even if the peaks Dopplered a bit from planetary orbital motion.

      On the flip side, no--we are not broadcasting any barycentric signals right now. An alien SETI@Centauri project might assign us a slightly lower priority because we're not making a deliberate effort to be noticed. Nevertheless, continuous radio and television signals across multiple frequencies would probably make us quite an interesting target to any race with good enough detectors and large enough dishes.

  • "First, the least reliable signals must be weeded out in a process called "data integrity check", and those that are most likely the result of detection or computer error are eliminated."

    This just proves the conspiracy to hide alien life from us!

  • migrating aliens (Score:3, Funny)

    by mydigitalself ( 472203 ) on Thursday December 05, 2002 @11:58AM (#4818554)
    i understand the 100% scientific approach to weeding out certain stars that have not been around that long:
    When it comes to scoring signals, however, not all stars are equal. This is because, according to SETI wisdom, some stars are more likely to host a communicating alien civilization than others. Thus, for example, only main-sequence stars are considered for signal-scoring purposes, excluding red giants and white dwarfs. Short-lived stars, whose lifespan is only a few million years, are also excluded from consideration, since complex life would not have had time to evolve in such an environment. Nearby stars, on the other hand, get "extra credit" in their scoring, since it would be comparatively easier to communicate with civilizations in our galactic neighborhood than with those in distant parts of our galaxy or beyond. Finally, the more similar a star is to our own Sun, the higher its score, since it would be more likely to host a civilization similar to ours.

    and maybe this sounds really really stupid and like i should stop watching star trek - but i don't actually watch it! but surely a far advanced alien race could be migratory and move to one of these less advanced planets. like maybe for the sunshine?
  • While SETI@home will be using the Arecibo dish to observe the most significant 100 signals, wouldn't it suck for the intelligent signal was the 101st? If there are billions of signal candidates, I imagine the 101st signal is still interesting.

    I also wonder if they are going to put the most interesting signals in the middle of their dish time, so that the operators have some warm up time... Putting the most interesting ones first might not be such a good idea if the engineers haven't had a chance to have their coffee/tea/etc. kick in.

  • Tycho2 vs. Hipparcos (Score:4, Informative)

    by KjetilK ( 186133 ) <kjetil AT kjernsmo DOT net> on Thursday December 05, 2002 @12:01PM (#4818581) Homepage Journal
    I'm a bit surprised that they refer to the Hipparcos [estec.esa.nl] catalogue as the most comprehensive star catalogue, when the Tycho 2 [astro.ku.dk] catalogue is far bigger.

    Sure, the astrometry (positions) in Hipparcos are better than in Tycho 2, and Hipparcos contains more information about the stars than Tycho 2 (e.g. variability), but still. I would in fact think that Tycho 2 would be better for SETI than Hipparcos, but they may have their reasons.

  • Can I get the filter they're using for my email?

  • Seeing a Spread Spectrum signal is very hard (Score:5, Interesting)

    by asmithmd1 ( 239950 ) on Thursday December 05, 2002 @12:14PM (#4818669) Homepage Journal
    The Seti project is not even looking for one. I would guess this is the way radio spectrum will be used in our future. Radio technology was developed before cheap microprocessors, but if the situation had been reversed we would all be using spread spectrum radios that frequency hop using pseudo-random sequences. Even to us, less than 100 years after developing radio I can imagine a time soon when large chunks of spectrum will be shared and the day of the single carrier radio will be over, it just makes more sense. If you don't know the psuedo-random sequence a spread spectrum signal looks exactly like noise. And what range of frequecies will the signal be spread over? For a signal bandwidth of a few kilohertz (like voice) a spread of a megahertz or two is spread sectrum. But to an alien, who knows what their communication bandwidth is. They may be spreading over a gighertz range, or even into infra-red and ultra violet. A signal like that would be completely undetectable. Who knows, maybe the cosmic background radiation is alien communication, after all it is not evenly spread out across the sky like you might expect.
    • Well, If I were an Alien and I wanted to send a signal I'd either.

      Send a simple one, so that simple people can find me.

      Or, send a hard one, and run away if anyone detects it.
    • I guess the validity of searching for narrow-band signals depends on
      whether you are trying to hear incidental transmissions (such at the
      aliens' TV and radio broadcasts) - or whether you hope to hear
      a signal that they are deliberately sending for other civilizations
      (such as ours) to hear.

      If it's the former - then I think we are already doomed because we
      don't have enough sensitivity in the Aracebo detectors to hear signals
      of that power over those distances.

      If it's the latter - then it's pretty doubtful that they'd send something
      that's so hard to detect and decode unambiguously. Spread-spectrum
      signals are a LOT like white-noise with all kinds of pseudo-random
      mangling going on. That's going to be EXCEEDINGLY hard to detect - so
      why would the aliens be talking to us in that way.

      For signals that we are INTENDED to receive, we have to assume that they
      are DESIGNED to be easy to detect and unambiguously different from
      other kinds of radio signal that we might see in space. Spread-spectrum
      would be an exceedingly poor choice for that.

  • Suspicous process (Score:3, Interesting)

    by Katalyzt ( 546182 ) on Thursday December 05, 2002 @12:20PM (#4818712) Journal
    Some news at long last. For some time now my requests for more information in the sci.seti newsgroup about the SETI@Home process and research results so far have met with silence. The so called progress pages [berkeley.edu]on the SETI site gradually slide into incoherence as the analysis gets deeper. So after several years of effort what do we finally have? ... 24 hours of telescope time in 2003 ! Now that speaks volumes about the significance of all the work done and the urgency that has been attached to it. What happened to this great project?
  • I get the feeling that we, metaphorically speaking, wall flowers. Leaning agains the wall at the side of the dance waiting for _someone_else_ to some invite us out to play.

    Other than the accidental leakage, are we beaming out anything intentional for SETI@marklar?

  • SBI@home.com (Score:2, Funny)

    by Anonymous Coward
    I was hoping people would like to join my project of SBI@home (Search for Buluga Intelligence). I will be puttting a microphone in the middle of the Red River (stationed in Winnipeg, Manitoba Canada), in hopes to pick up signals sent directly to us, with intent, from buluga whales. Once we have communication with them, we will attempt to pin point exactly where the buluga whale was when he/she sent this message to us. Even tho the signal may have taken 1000 days to reach us, and even tho we would be analyzing signals sent from the buluga whale sometime in september of 1998. THEN - We will attempt to decipher the message and send back the signal with a witty 'first reply' joke ... Which will be the first intergalactic joke. (next to seti@home that is) ...

    THEN - me and the buluga will chill and have beers

  • More info on the top 100 (Score:5, Interesting)

    by i8a4re ( 594587 ) on Thursday December 05, 2002 @01:11PM (#4819215)
    There are two things I'd really like to take a look at, and I'm sure I'm not the only one.

    First, there is a program that can convert the work unit files into a wav file. I think it would be pretty cool to listen to some of these top 100 signals. I've played with the program on quite a few work units and never been able to hear anything but static. As strong as the top 100 signals are, you should actually be able to hear something.

    Second, there are a few places on seti's and related sites that show a picture of what a good signal looks like. Why don't they take a grad student and make him run through the top 100 signals and record what the graphics look like when it is processed?

    I've actually emailed them before and requested both of these. I've never gotten a response nor have they posted either. If they have, then I've just missed it.

  • WHOOOOHOOOOOO! (Score:4, Funny)

    by chersk ( 154349 ) on Thursday December 05, 2002 @01:17PM (#4819265) Homepage
    100 Best Singles!... Thats what i'm Talking about!.. 100 hot alien singles with hot alien bod's and hot.... uh... oh.... signals.... dang..

    never mind....

  • Making it harder for considerate aliens? (Score:4, Funny)

    by sbaker ( 47485 ) on Thursday December 05, 2002 @02:06PM (#4819590) Homepage
    So we little green aliens go to all the trouble to put the
    transmitter far away from any other radio sources (like stars
    and galaxies) - we shift the frequency to compensate for the
    orbit of your planet around your sun - we listen to your
    transmissions and send ours back on channels we know you
    must be listening to - and we get modded down for all of
    those things? Damn!

    So what DO we have to do to get more Karma at Seti?

  • The first message will be something like... (Score:4, Funny)

    by Lobsang ( 255003 ) on Thursday December 05, 2002 @02:30PM (#4819795) Homepage
    Dear Sir/Madam/Globunsk/Srhamel/Goot:

    I'm the ruler of Andromeda-3, an M Class Planet in the constellation of Andromeda. My father, the fifth ruler in the Pfthoskkkrkfhhdfkfk dinasty has been robbed. If you could lend me your intergalactic bank account so I can transfer my funds to Alpha Centauri... :)

  • What about our future? (Score:3, Insightful)

    by SiliconEntity ( 448450 ) on Thursday December 05, 2002 @04:27PM (#4820888)
    The interesting part about attitudes towards SETI is what they say about our own future. What is happening with our civilization? Where will we be in 100 years? In 1000?

    Many people are pessimistic. They think we're bad and getting worse. They expect that we will destroy ourselves soon, or sink into a dark age, or otherwise lose the ability to communicate with the stars. So they can imagine a galaxy full of life but not much of it communicating at any given time.

    But let's suppose that things continue on as they have. Look at the grand sweep of human history. We see a continual growth of capability and power. Even a poor person today in the West has technology which would have been unavailable to the richest person in the world 100 years ago.

    Imagine that this continues to happen. Technology not only advances, it speeds up. The next 100 years bring more changes than the last 1000 years. Nanotechnology, biotech, AI, physics advances; we could be living like gods in 100 years.

    And let's assume that social trends continue. Racism and sexism was ubiquitous 100 years ago. Now they are recognized as great evils. As our power grows and our moral sensitivity increases, we will want to help those less fortunate than ourselves. We will end poverty and suffering among humans, because it will be easy compared to the power we have. We will turn to the higher animals, and do what we can to improve their lives as well.

    And we will turn outwards. We will reach out into the galaxy with communications and explorations. It will take centuries, millennia, but as our capabilities grow we will eventually find even the great interstellar distances easy to cross. We will search the galaxy for life, ready to cherish and protect anything that we find. And if we could meet a culture less advanced than our own, we would do what we could to ease their suffering while still respecting their chosen path.

    This may seem like an absurdly optimistic vision, but it's nothing different from what has happened in the past! Anyone who looks with clear eyes at the record of human history and who extrapolates it forward should see this as a very plausible and likely future path. The reason that it's not explored much in literature is because there aren't that many dramatic possibilities in a world which is as much improved over the present as our own world is over the past.

    The point is that if this is the likely path for a civilization, it would suggest that other cultures in the galaxy would also be spreading outward and would probably be here by now. The fact that we don't see them, that we stumble along and still suffer great and preventable catastrophes, suggests that really life is not so prevalant in the galaxy after all.

    So ironically, both the optimistic and the pessimistic view of humanity's future suggest that SETI won't work. The pessimists believe that any advanced culture will wipe itself out; and the optimists believe that such a civilization will spread through the galaxy and render aid to less developed worlds. Either way we won't find intelligent signals on our expensive radio telescopes.
    • Anyone who looks with clear eyes at the record of human history and who extrapolates it forward should see this as a very plausible and likely future path.

      This is delusional optimism. Anyone who looks with clear eyes at the record of human history (and pre-history) sees that localized human socieities follow a predictable pattern of expansion followed by dieback. Sometimes the cause is external -- war or invasion or disease or climate. Sometimes the cause is internal: stasis, political disorganization, social transformation, resource exhaustion. Every single piece of available evidence points to this conclusion -- yet you somehow manage to convince yourself of some privileged exceptionalism that will enable your society to endure? I have a bridge you might be interested in...

      The various human civilizations that have energed since the Holocene were lucky to be existing in an especially mild inter-glacial period not characterized by hyper-aridity. This is a special and situational set of circumstances that cannot be exxpected to continue indefinitely.

  • OK... (Score:3, Interesting)

    by anthony_dipierro ( 543308 ) on Thursday December 05, 2002 @04:28PM (#4820893) Journal

    What are the odds of a random collision of atoms of a certain solar system producing life?

    What are the odds of a random string of radio signals mimicking life?

    If B>A, we have some problems.

  • Really hope they don't have an RIAA (Score:3, Funny)

    by Antity ( 214405 ) on Thursday December 05, 2002 @07:29PM (#4822445) Homepage

    Imagine some alien RIAA-like organization finds out about this SETI project that distributes their valuable inter-universal IP-protected radio signals to thousands of computers all over a damn whole planet!

    Hopefully there's just a flat yearly fee we're allowed to pay to the broadcasters...

    Their lawyers will go nuts if they ever find out.

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