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Space Communications Software

SETI@Home Adds New Search Method 191

Posted by Soulskill
from the look-for-interstellar-torrents dept.
Adam Korbitz writes to point out that SETI@Home has added a new algorithm for use in evaluating signals from outer space. It's called "Astropulse," and they've made the scientific details available. Quoting: "The original SETI@home is narrowband, meaning that it is listening for a particular radio frequency. That's like listening to an orchestra playing, and trying to hear when anyone plays the note "A sharp." Astropulse listens for short-time pulses. In the orchestra analogy, it's like listening for a quick drum beat, or a series of drumbeats. Since no one knows what extraterrestrial communications will 'sound like,' it seems like a good idea to search for several types of signals. In scientific terms, Astropulse is a sky survey that searches for microsecond transient radio pulses."
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SETI@Home Adds New Search Method

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  • Surprising (Score:5, Insightful)

    by FeatureBug (158235) on Sunday July 27, 2008 @01:25PM (#24359305)
    I find it slightly surprising it has taken the SETI project how many years to start checking broadband as well as narrowband signals. All those years spending a fortune in resources but only checking narrowband seems rather a waste of time. I would have been checking all sorts of broadband signal types from the very beginning.
    • by Ilgaz (86384) on Sunday July 27, 2008 @02:41PM (#24359943) Homepage

      Broadband wasn't common in 1999. Now they figure aliens must have upgraded too. ;)

    • Re:Surprising (Score:4, Interesting)

      by smaddox (928261) on Sunday July 27, 2008 @03:06PM (#24360205)

      They chose 1420 megahertz for a good reason:

      There is, however, a pronounced minimum in the radio-noise spectrum. Lying at the minimum or near it are several natural frequencies that should be discernible by all scientifically advanced societies. They are the resonant frequencies emitted by the more abundant molecules and free radicals m interstellar space. Perhaps the most obvious of these resonances is the frequency of 1,420 megahertz (millions of cycles per second). That frequency is emitted when the spinning electron in an atom of hydrogen spontaneously flips over so that its direction of spin is opposite to that of the proton comprising the nucleus of the hydrogen atom. The frequency of the spin-flip transition of hydrogen at 1,420 megahertz was first suggested as a channel for interstellar communication in 1959 by Philip Morrison and Giuseppe Cocconi. Such a channel may be too noisy for communication precisely because hydrogen, the most abundant interstellar gas, absorbs and emits radiation at that frequency. The number of other plausible and available communication channels is not large, so that determining the right one should not be too difficult.

      Source:http://www.ufoevidence.org/documents/doc252.htm

      More recently scientists have considered neutrino signals to be much more likely for alien communications since they can be sent across the universe with minimal signal degradation. The problem is that they are very hard to sense, and even harder to generate as a controllable signal.

    • Re:Surprising (Score:5, Informative)

      by Yvanhoe (564877) on Sunday July 27, 2008 @03:27PM (#24360369) Journal
      No ressource was wasted. I suppose it takes more CPU cycles to check for both narrow and broad signals. The SETI project started by trying to have the lowest CPU usage possible and even by checking signals in a single wavelength in all the sky, it required the SETI@home project : touted as the biggest computation of all human history. Now they apparently are near completing their initial goal of checking for signals in the hydrogen wavelength, so they propose to use more power to check other forms of possible signals.
  • Yes but (Score:4, Insightful)

    by negRo_slim (636783) <mils_oRgen@hotmail.com> on Sunday July 27, 2008 @01:25PM (#24359309)
    Haven't we already covered this? The cost in electricity for them to use my "unused" resources is not worth it for SETI which offers and most likely will never offer any tangible benefit to our society.
    • Re:Yes but (Score:5, Insightful)

      by vertinox (846076) on Sunday July 27, 2008 @01:39PM (#24359415)

      The cost in electricity for them to use my "unused" resources is not worth it for SETI which offers and most likely will never offer any tangible benefit to our society.

      True, but who are you to say what others due with their free CPU cycles?

      Personally, I like protein folding, but if other people want to look for alien life with their cycles then its their computer.

      • by arth1 (260657)

        True, but who are you to say what others due with their free CPU cycles?

        "Do", not "due". And I got the right to say the first time we had brownouts in my area, and other people's energy wasting affected me. Not only do you waste an extra 40-100W per computer, but during summer, your ACs work harder too, cooling down that extra heat energy.

        • Re: (Score:2, Insightful)

          by strelitsa (724743) *
          When you start paying your neighbor's electric bills, then you will receive a bit more credibility when you attempt to tell them how much or how little electricity they get to use. Let me be the first to solemnly assure you that your brownouts aren't being caused by the kid next door running SETI@Home or downloading Britney Spears pr0n.
          • Re: (Score:2, Insightful)

            by arth1 (260657)

            Let me be the first to solemnly assure you that your brownouts aren't being caused by the kid next door running SETI@Home or downloading Britney Spears pr0n.

            No, it's being caused by tens of thousands of kids of all ages running SETI@Home, having ACs set to sub-70 temperatures, running dryers with hot air exhaust, and otherwise wasting energy.

            When you start paying your neighbor's electric bills, then you will receive a bit more credibility when you attempt to tell them how much or how little electricity they

            • by jlarocco (851450)

              The only entity you have a right to bitch at is the power company that isn't providing the power they agreed to provide.

              It's none of your business what other people use their electricity for.

      • Re: (Score:2, Insightful)

        by Lazy Jones (8403)

        T>True, but who are you to say what others due with their free CPU cycles?

        CPU cycles aren't free these days (with good power management), they cost electricity and producing electricty usually leads to CO2 emissions and thus contributes to global warming.

        Your pointless SETI computations are heating up my planet, so I can bloody well complain about it.

        Now, finding a large prime number on the other hand, might earn me an entry in the Guinness Book of World Records...

        • Re: (Score:2, Funny)

          by Joebert (946227)
          Well this is my universe & I say the Earth needs to warm up so I can keep my pet dinosaurs there again.
      • Re: (Score:3, Interesting)

        I wonder what the carbon footprint of Seti@Home is...electricity doesn't just grow on trees you know...
        • by ameline (771895)

          > electricity doesn't just grow on trees you know...

          It does if you generate electricity by burning firewood :-)

    • Re:Yes but (Score:5, Insightful)

      by FlyingSquidStudios (1031284) on Sunday July 27, 2008 @01:45PM (#24359475) Homepage
      The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.
      • Re: (Score:3, Insightful)

        by Stan Vassilev (939229)

        The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.

        Sure, finding alien life will have a lot of impact. The thing is SETI won't do that, at least as far as basic physics and math is concerned.

        But of course, it may end up replacing out outdated superstitious beliefs, and replacing them with more modern superstitious beliefs, such as trying to catch alien radio on our satelites. The parallels between doing this, and an old-school prayer to God are quite ironic.

      • Re:Yes but (Score:4, Insightful)

        by Memroid (898199) on Sunday July 27, 2008 @01:54PM (#24359539)
        Yes, but just think of how many more crazy religions it would spawn...
      • Read the Rama series by Arthur C. Clarke and Gentry Lee, crappy fiction after the first one, but they examine things just like this.

        And personally, extra-terrestrial life doesn't contradict my personal Christian beliefs.

        • So did Jesus die for the aliens' sins as well or are they all just bound straight for hell?
        • ...And why should it? Even a biblical literalist would have no good reason for believing we're alone in the universe.

          Even believing that humans are Capital G God's chosen people, you'd have to extend the definition of "people" to mean flartghs from the planet ftang. Maybe Capital G God has some chosen flartghs as well.

          The only people who will be threatened by the sudden discovery of intelligent extraterrestrial life are the ones who use their religion as a justification for their own bigotry and mistreatm

      • To paraphrase someone far smarter than me on the results of the Drake Equation, when it comes to proving whether extraterrestrial life exists or not, either answer will be astounding.

      • Highly Debatable (Score:4, Insightful)

        by Crazy Taco (1083423) on Sunday July 27, 2008 @03:26PM (#24360361)

        The proven existence of intelligent extraterrestrial life will have a profound effect on a lot of people's core religious beliefs. That alone will have a major effect on society and it might just turn a few people away from their outdated superstitious beliefs. I consider that a tangible benefit.

        Yes, but is there any alien life? Certainly there's been no evidence of any, though you talk as though it certainly, and inevitably, exists. It sure sounds like you are the one making assumptions and promoting a faith based argument!

        And as for this changing anyone's beliefs, that's highly debatable. Christian author CS Lewis wrote a trilogy in the late '40s that imagined intelligent life to be on both Mars and Venus. He was a noted apologist and theologian for the Christian faith, and he had no problem with considering the existence of extraterrestrials. (Note: The starting book of the trilogy was called Out of the Silent Planet).

      • Sure it will. Just like the idea that humans weren't actually created from earth, but rather gradually evolved from other lifeforms totally changed the religious landscape.
      • Quite the opposite, it will fuel existing movements, and as well as start new ones, such as: Raelians [wikipedia.org], Heaven's Gate [wikipedia.org] and many other alien based religions [wikipedia.org].

      • Honestly, I think that it'd be depressing, should we find clear and obvious evidence of alien life and communication through SETI, only to learn that the place is a million light years away and this fellow "illuminated society" is most likely either dead, decadent, or so far beyond us that we'd be unable to relate.

        Even if they were not dead, nobody would ever know what they were saying before their own lives were over. It's the feeling of isolation from other "like minds" which drives people mad, not the a

    • by bazorg (911295)
      well, I play in the lottery. the probability of success is extremely slim but the prize is very high and the cost of the missed attempts does not impact my finances that much.
    • by TeknoHog (164938)
      It takes resources to do fundamental science, and it rarely generates immediate profit. Look into the history of science for things that were once considered useless and whacky, and now an essential part of our society. For example electromagnetism.
    • by sznupi (719324)

      You don't mention that explicitly in your post, but I guess you prefer to run other distributed computing projects, the ones with "more tangible benefits".

      But consider...most of them are functionin thanks to BOINC infrastructure developed by ...SETI@home, and also they got on the bandwagon of distributed computing after the idea was hugely popularised by...SETI@home.

      So perhaps S@h gave some tangible benefits after all?...

  • by Anonymous Coward on Sunday July 27, 2008 @01:26PM (#24359319)

    As the information in a radio signal approaches the Shannon limit, it becomes indistinguishable from noise to an outside observer. Any sufficiently advanced civilization will have the technology to maximize the information sent in a radio signal. Therefore we will not be able to detect radio signals from other civilizations (except for perhaps a 100-200 year period in their evolution where they use inefficient radio signals)

    • Why not? (Score:3, Insightful)

      by FeatureBug (158235)
      Except for a huge assumption you're making: that an advanced civilization wouldn't want to broadcast a distinctive, easily decoded, narrowband signal. Perhaps they might want to do it to announce their existence to the rest of the universe, even though they would have the know-how to sendmuch more efficient broadband signals.
      • Except for a huge assumption you're making: that an advanced civilization wouldn't want to broadcast a distinctive, easily decoded, narrowband signal.

        They do broadcast a signal, and so do we. It's the spectrographic signature of high Oxygen content in the atmosphere. [cnn.com] Why would they send a technologically crafted signal when their entire atmosphere is already broadcasting for them ? If we wanted to make contact with them surely we would warp over and introduce ourselves, right? For them to blast radio wav
        • Yes, but there is a huge difference between natural spectral emissions by atoms and molecules of oxygen and other elements, and purposive signal transmission by an ET. Contrary to the article you linked, detecting the former doesn't imply the existence of ETs. That's why SETI is trying to detect the latter.
    • by Free the Cowards (1280296) on Sunday July 27, 2008 @01:37PM (#24359405)

      SETI is not searching for accidental transmissions or leakage. SETI is only searching for deliberate beacons being sent by alien civilizations. SETI's techniques cannot detect random radio chatter and are not intended to.

      • by 4D6963 (933028)
        If so we're out of luck. I mean how often do we even deliberately try to send beacons to eventual alien civilizations? We couldn't find ourselves in a giant space mirror the way we're doing it.
        • SETI is not trying to find civilizations like ours. It is trying to find significantly more advanced civilizations which are deliberately trying to contact civilizations like ours.

          • by 4D6963 (933028)

            [SETI] is trying to find significantly more advanced civilizations

            Great, so what you're saying is SETI is just a bunch of elitist? That's grand, I just can't wait until they make the Earth move to a gated planet community.

            Don't get me wrong, that would be great, with all these asteroids impacts we've had these last few eons in our neighbourhood..

    • by gardyloo (512791)

      Could you expand a little on that statement? I have two interpretations:

      * Noisy-channel capacity theorems state that if information is being sent at less than channel capacity, error correcting codes can, in principle, ensure no errors on the part of the receiver, even in the presence of noise (in which case outside observers should have no problems decoding any messages);

      * However, if information is being sent at over channel capacity, errors can grow without bound. If some ci

    • by khallow (566160)

      As the information in a radio signal approaches the Shannon limit, it becomes indistinguishable from noise to an outside observer.

      Doesn't work that way. The Shannon limit restricts how much information you can pass in a noisy channel. SETI is looking for a very restricted question, is there a signal? That's just one bit of information. Listen long enough on the channel and that bit of information will come through, no matter how noisy the channel is.

  • Strange that they are only doing that now - haven't they seen Contact?

    • by 4D6963 (933028)

      Strange that they are only doing that now - haven't they seen Contact?

      What the hell are you talking about? In Contact the SETI is basically just a bunch of hippies who time-share radiotelescopes and look for signals by listening into headphones. Here we're talking about listening to bands hundreds of megahertz wide. Very different.

  • It's very difficult to keep radio waves from spreading out in many directions, thus weakening the signal that can be detected by a distant receiver in any particular direction. Light, on the other hand, being much easier to focus into a tight beam, tends to stay within a narrower cone of space, leaving a stronger signal in the direction of aiming.

    If I wanted to send a signal across the universe, I'd use light, not radio waves.

    So, why is SETI still limiting itself to searching for signals in the radio spec

    • by MLCT (1148749)
      They are both part of the same thing, the EM spectrum - and light has a much higher chance of being absorbed by interplanetary "stuff" before it ever reached us (hence why we can use FM radios indoors, but not something in the visible spectrum).

      Radio can be directional as well (microwave transmitters) - but all the worry about focussing is not really on the agenda - any alien who puts the effort into "focussing" a beam on us might as well just use some more obvious means of catching our attention - a bin
      • Re: (Score:2, Interesting)

        by Toffins (1069136)
        Err, in fact we can easily see the light from stars that are billions of light years away, without light absorption by "interplanetary matter" being a big problem. Of course, we can detect other types of EM too at similar distances, including radio, e.g. using radio telescopes. And, of course, all types of EM - light, radio, microwave - is absorbed and scattered to some extent by matter. But my point is, across the whole spectrum, it is light that can be most easily focussed into the tightest of beams with
        • by photonic (584757)
          True, but only if you know were you are pointing (they do this with satellites [esa.int]). If ET does not know where we are, and just randomly points his laser in the sky, the detection chance drops enormously, I guess the two effects cancel each other in the detection probability. Also note that any light you sent will might be lost in the background radiation of the star or the planet (I don't know if this is better or worse with radio).
          • by Toffins (1069136)
            Why wouldn't ET know exactly where to point a beam? We have science projects searching the universe for solar systems similar to ours with medium-size planets at Earth-sun distances where liquid water could exist. We find a new such solar system every few months, and get a very precise location too.

            ET might be running similar projects. Every time ET finds a new candidate solar system, ET just points a laser at it. At such distances, with non-zero divergence of the laser beam, all of the planets in that sol

        • The problem with a tight beam is that although you may get further, you only get one narrow beam that's unlikely to be crossed. A radiant energy is far more likely to be detected if it emanates in all directions.

          So, combine your tight beam with continuous oscillation in all directions, and then you've got something.

      • by Toffins (1069136)
        Re. what type of signal to send:

        I'd think sending something like a tight beam of intensity-modulated monochromatic light would be more obviously unnatural than a periodic binary broadband pulse, which could just be mistaken for a weird sort of pulsar emission. Or intensity modulate it to N different levels giving I(t+k_i) where the k_i are some short period sequence of small integers, and N is a prime number. If we saw a weird beam of light like that, we'd probably assume it had a an intelligent origin.

  • A terrible analogy (Score:5, Interesting)

    by no reason to be here (218628) on Sunday July 27, 2008 @01:45PM (#24359467) Homepage

    As a musician and a recording engineer, I feel I must comment on the analogy used.

    For someone with a trained ear picking out an A#, or any particular note, shouldn't be all that difficult, especially if that note is tonic, 3rd, 4th, 5th, or other similar high recognizable interval from the tonic. It would be trivially easy for someone with perfect pitch to pick out a particular note.

    I suppose the analogy might hold if we compared the prior SETI searching signals to be like a man who is deaf in his right ear turning his left ear away the orchestra to try and determine if the 2nd piccolo is playing sharp on A#, and now, SETI is that same man, facing forward with a brand new hearing aid, merely trying to pick out staccato notes.

    • by Derosian (943622)
      So basically all we need is human-level thinking computers and we might find E.T. life?
    • by 4D6963 (933028)

      No it's a good analogy, although worded it a manner that may make its interpretation prone to confusion. "and trying to hear when anyone plays the note "A sharp."" should really be "and trying to hear nothing but "A sharp" notes".

      It has nothing to do with identifying the pitch of a note as you seem to have misunderstood, it has to do with not being able to hear anything but one note in an entire piece.

    • Stop trying to hear the orchestral, instead realize the truth; There is no orchestra.
  • by photonic (584757) on Sunday July 27, 2008 @02:08PM (#24359637)
    The type of data analysis they perform on these radio signals looks pretty similar to what they do with the data from gravitational wave detectors such as LIGO [caltech.edu], which also look at both periodic sources and short glitches. In that community, they do an estimation of detection rates based on hard science: number and distribution of stars and expected rates of supernovae etc. Detection rate for last years' science run is on the order of 1 per 10 to 100 years, which should increase to hopefully tens per year with the advanced detectors that should come online in several years. Nothing has been detected yet, but this is more or less understood. If the advanced detectors detect nothing, the taxpayer owes an explanation.

    I wonder if similar detection rates have been calculated for SETI (e.g., assume ET having a transmitter of 1 MW, at what distance would you still detect anything? And how many life supporting planets are in that range? ) This will depend a lot on the parameters in your Drake's equations, but they should at least give some order of magnitudes. I remember reading some skeptic article several years ago, which claimed that even with optimistic estimates, the chance of detecting anything would be absolutely zero.

    Until that time, I rather waste my computer cycles on the LIGO data (Einstein at home [uwm.edu]) or one of the various medical applications (e.g. Folding at home [stanford.edu]), which produce scientific results today.

  • Ironic (Score:4, Insightful)

    by Randall311 (866824) on Sunday July 27, 2008 @02:32PM (#24359849) Homepage
    Does anybody else find it ironic that we are looking for intelligent extra-terrestrial communications on the very same frequency that we (an intelligent species) are prohibited from transmitting on? The 1.420 gigahertz frequency was chose (I believe) because of the hydrogen line. It would seem to me that a more effective methodology would be to do a spectrum sweeping search. The odds of any intelligent species transmitting on just one frequency are unlikely enough. Combine that with the fact that we are only listening on one frequency. Now we can compare finding a needle in a haystack as trivial in comparison.
    • by 4D6963 (933028)

      Pffft, but obvious, the aliens will have thought of the same thing as us, that we should reserve the 1.420 GHz frequency for interplanetary communications and that we would be listening and that they would be the ones listening.

      Now excuse me while I go back to listening to some radio frequency I think would be good for two persons to communicate on and wait for someone I never communicated with before to talk to me on this agreed frequency.

    • Re:Ironic (Score:4, Insightful)

      by Ransak (548582) on Sunday July 27, 2008 @03:27PM (#24360365) Homepage Journal
      The concept of SETI is to look for radio signals that have been intentionally directed toward us (ie, not stray signals).

      The SETI line of thought is if another civilization is intelligent enough to understand the Hydrogen Line and the Microwave Window and that another civilization - us - would understand that as well and use it for radio astronomy, the frequency of Hydrogen (1420.40575 MHz) would be the most likely place we would be listening since the universe is mostly made up of it from what we can tell so far.

    • by Pedrito (94783)

      The 1.420 gigahertz frequency was chose (I believe) because of the hydrogen line. It would seem to me that a more effective methodology would be to do a spectrum sweeping search. The odds of any intelligent species transmitting on just one frequency are unlikely enough.

      Well, first of all, they were dealing with limited computational power in the first few years, so they had to put limits on what they were searching for. Now that computational power is getting to be less of an issue, they're starting to spr

  • SETI, as primarily currently pursued, is unlikely to find anything. I sum up my perspective, "We don't talk to nematodes and *they* don't talk to us." It is useful to consider the difference in intellectual capacity between humans and nematodes is far less than that between Matrioshka Brains and us.

    Most advanced extraterrestrial civilizations are going to be far far ahead of us. At the point where they have constructed Matrioshka Brains. The intellectual capacity of an MBrain is roughly a trillion trillion times that of a human brain. They can simulate the history of entire humanities in seconds. We are simply not of interest to them.

    There are 3 ways to detect MBrains.
    1. Stellar occultations (similar to some of the exoplanet searches now being done).
    2. Gravitational microlensing studies (also being done).
    3. Large scale mid-to-far IR surveys looking for bright IR objects that do not appear to be visible (not being done because our far IR detectors are extremely poor and not particularly sensitive; and they must be operated from space so they are $$$).

    The observant will note that none of these involve using computer cycles for the analysis of radio wave noise. The astronomer geeks will notice that long term backyard surveys searching for exoplanets using variations in stellar brightness might either capture candidate stars with exoplanets or perhaps an occasional gravitational microlensing event or maybe an MBrain traveling through the galaxy on its way to the nearest carbon white dwarf star (because they need more carbon for extreme nanotech) or a stellar gas nebula for a fueling pit stop. The extremely astute might notice that should sufficient numbers of these be discovered then there might be another explanation for all of the "dark matter" which doesn't result from the physics of the universe but from the natural activities of intelligent life. (Perhaps making the theoretical physicists extremely unhappy.)

    It is also the case that to scan large fields of stars for variations in brightness and separating the normal variable stars from those which are "unusual" would not be a small use of ones spare computer time.

    • by Jimmy_B (129296)

      Most advanced extraterrestrial civilizations are going to be far far ahead of us. At the point where they have constructed Matrioshka Brains. The intellectual capacity of an MBrain is roughly a trillion trillion times that of a human brain. They can simulate the history of entire humanities in seconds. We are simply not of interest to them.

      Every sentence in this paragraph is a ridiculous and unjustified assumption. Until we observe an alien intelligence, we cannot know its capabilities or its motives.

      • by Nazlfrag (1035012)

        Indeed, such a species may have the capabilities to create a Matrioshka brain yet chooses not to, for any number of reasons. Perhaps they cannot ethically or morally justify the destruction of a solar system, or more likely have a reasoning which is simply beyond our comprehension.

        • by bradbury (33372)

          Intelligent species, esp. intelligent species with tool and machine making capabilities have control over their destiny. Evolution moves from environmental determination to self-determination. We have yet to really wrestle with that. Those who understand molecular biology, transhumanism, the end points of Moore's Law and molecular nanotechnology have some grasp of where species can go (or as you point out choose not to go).

          But the Earth evolved for several billion years without any significant life, then

      • by bradbury (33372)

        If you evolve to the limits that physics allows, ones longevity is measured in hundreds of billions to trillions of years -- much older than our universe now is. The reason for doing this is the most simple and natural one that can be imagined -- simple survival. Species that for one reason or another choose not to survive will not be detected.

        Whether it is true now (and Lineweaver's work on the fact that a majority of the "Earth's" in our galaxy are much older than ours and therfore it may be) or not --

  • ...must we sift through all those old tapes?
  • by Animats (122034) on Sunday July 27, 2008 @07:47PM (#24362249) Homepage

    Well, that's progress. I've criticized SETI@Home for looking for "carriers" signals with a large fixed-frequency component. They need to get beyond that. AM and FM signals have carriers (Analog TV is AM video with an FM audio subcarrier), and as a result, 80% of the signal energy is wasted. None of the more modern digital transmission systems have strong carriers.

    The more efficient a transmission system, the more it looks like white noise if you don't know how to decode it. If there's some big repetitive component like a carrier, or the horizontal and vertical retrace intervals in analog TV, it's inefficient. The FCC wouldn't approve any new transmission system which wasted bandwidth like that, and the old ones that do are being phased out.

    So SETI systems that look for carriers are looking for civilizations advanced enough to generate high-power RF signals, but not advanced enough to use more efficient digital modes. Our civilization went through that period in under a century. It's also fairly clear that nobody in our stellar neighborhood is continuously sending a strong RF carrier in our direction; that's been looked for.

    Question: can the new SETI algorithm pick up an HDTV broadcast station?

  • Am I the only one that thought the last line, "In scientific terms, Astropulse is a sky survey that searches for microsecond transient radio pulses." was easier to understand, in its brevity, than the supposedly layman explanation preceding it?

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