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Sci-Fi Communications Science Technology

Why We're Looking For ET All Wrong 275

Posted by samzenpus from the won't-work dept.
StartsWithABang writes: When you consider that there are definitely millions of planets in the habitable zones of their stars within our Milky Way galaxy alone, the possibility that there's intelligent life on at least one of them, right now, is tantalizing. But we're in our technological infancy, relatively speaking, having only been broadcasting electromagnetic signatures visible by an alien civilization for around 80 years. Unsurprisingly, we're looking for exactly the types of signals we're capable of sending, but what if that's totally wrongheaded? Based on how technology is evolving and what the Universe is capable of, perhaps we should be looking not at electromagnetic radiation, but neutrino or gravitational wave signals from the distant Universe to search for alien civilizations.
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Why We're Looking For ET All Wrong

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  • Same reason we're looking for earth-like life (Score:5, Insightful)

    by Kjella ( 173770 ) on Sunday September 13, 2015 @10:49AM (#50513643) Homepage

    It's the one life we know exists, if we find aliens with a totally different physiology or totally different technology that's nice but we have no idea of what to look for. It's unlikely that aliens expect us to tap into their communications, if they are trying to ping us they probably do it using all possible channels. And we know at least one of them, it's unlikely a civilization that can do what he proposes hasn't invented the radio.

    • Re:Same reason we're looking for earth-like life (Score:4, Insightful)

      by Anonymous Coward on Sunday September 13, 2015 @10:53AM (#50513665)

      Right, but the real question is, once radio is invented, how long will they keep using it?

      • Re:Same reason we're looking for earth-like life (Score:5, Insightful)

        by Beck_Neard ( 3612467 ) on Sunday September 13, 2015 @04:18PM (#50515229)

        I don't think it's unreasonable at all to consider that some form of EM communication will be used by advanced civilizations. EM radiation is just too easy to produce and detect and it enables very high bandwidths. The other technologies that the author is talking about - like gravitational wave communications or physical probes - have very very low bandwidths by nature of their design. General relativity dictates that it requires HUGE amounts of energy/mass to produce even feeble amounts of gravitational waves.

        The point about detecting neutrinos from fusion reactors is interesting but I don't think there's any way we could separate those neutrinos from background radiation.

        EM is likely to remain the most promising method for detecting ETI. Of course there's no reason that the EM radiation would be limited to the radio/microwave band. It could be based on light, or IR, or UV, or even X rays.

    • Re:Same reason we're looking for earth-like life (Score:5, Interesting)

      by elwinc ( 663074 ) on Sunday September 13, 2015 @10:56AM (#50513675)
      At the very least we should be looking for spread spectrum modulation methods. Amplitude and Frequency modulation are so last century. On the other hand, a good spread spectrum signal looks like band limited white noise, so we need better methods to detect it.

      • Re:Same reason we're looking for earth-like life (Score:5, Interesting)

        by swillden ( 191260 ) <shawn-ds@willden.org> on Sunday September 13, 2015 @12:04PM (#50513995) Journal

        And further progress seems likely to continue using broader bands, including shorter wavelengths (up to and including visible light), cleverer encoding techniques, more encryption and lower transmission power. All of which will make it harder and harder to detect from interstellar ranges. I think the most likely scenario is that our civilization will only emit detectable radio waves for a couple of centuries, so if we assume a similar progression for other civilizations, what we're looking for with radio-band scanning is a short-term blip emitted by emerging technological civilizations. So we may as well look for the crudest, most easily detected forms, since looking for more advanced forms is harder and doesn't extend the window by all that much.

        • As communication becomes more advanced and efficient, it becomes harder and harder to detect, and even harder to decipher. Instead of looking for ET's communications, perhaps we should be looking for the heat signatures of Dyson Spheres [wikipedia.org].

      • At the very least we should be looking for spread spectrum modulation methods.

        Why would we do that?

        Look, every time we make major science advances, the engineering quickly follows, and we get better communications tech. Certainly frequency hopping is one of those advances, but it's not even a mid-point to what we'll be using when we have a completely cohesive theory of Physics.

        At least SETI only claims to look for signals intentionally sent out as a beacon to the most possible types of civilizations that

    • Radio is very noisy. Why would any advanced civilization think that it would be a great way to communicate over long distances? I would assume that any intelligent life-form would listen to the static in the background and think, there must be something better than this.

      • Because unless you have gravity modulation or the ability to shield neutrinos, and thus can use them for communications then you might have something.

        Actually using gravity would suck as every large mass would deflect your signal, and thus it is useless for interstellar comms.

        Neutrinos go through everything so in theory works if you can shield, create, and modulate them.

        • Modulating neutrinos would be tough since they're only affected by gravity and the weak subatomic force.

          Besides, any really advanced civilization would be using subspace for communications.....

      • Re: (Score:2)

        by elwinc ( 663074 )

        Radio is very noisy. Why would any advanced civilization think that it would be a great way to communicate over long distances?

        Because microwaves near the 21cm band pass through dust clouds that would block visible light and various other frequency bands, so its good for really long distance communication. Hydrogen 21cm detectors are also a good way to measure the large scale structure of the universe. See The Watering Hole. [astronomynow.com]

    • It's the one life we know exists, if we find aliens with a totally different physiology or totally different technology that's nice but we have no idea of what to look for. It's unlikely that aliens expect us to tap into their communications, if they are trying to ping us they probably do it using all possible channels. And we know at least one of them, it's unlikely a civilization that can do what he proposes hasn't invented the radio.

      Yes yes. Additionally, if there exists a self-aware life form too unlike us, we couldn't understand it, even if it were a bit smarter than us.

      Shoot. For all we know? If the dolphins had developed amphibiously, we'd be scattered about the stars by now.

    • Re:Same reason we're looking for earth-like life (Score:5, Interesting)

      by thinkwaitfast ( 4150389 ) on Sunday September 13, 2015 @12:00PM (#50513971)
      An interesting paper on xenopsychology [rfreitas.com] by Robert A. Freitas [wikipedia.org] (a senior fellow at the Institute for Molecular Manufacturing in Palo Alto, California.).

      See see Sentient Quotient [wikipedia.org]

      At present, human scientists are attempting to communicate outside our species to primates and cetaceans, and in a limited way to a few other vertebrates. This is inordinately difficult, and yet it represents a gap of at most a few SQ points. The farthest we can reach in our "communication" with vegetation is when we plant, water, or fertilize it, but it is evident that messages transmitted across an SQ gap of 10 points or more cannot be very meaningful. What, then, could an SQ +50 Superbeing possibly have to say to us?

      • Re: (Score:3)

        by epine ( 68316 )

        This is inordinately difficult, and yet it represents a gap of at most a few SQ points.

        Thanks for embedding a bright red hand print on my forehead. You do know that the difference between ice and water is only a few degrees Celsius? We've barely established that cetaceans even have an oral culture with anything in common with pre-historical human oral culture.

        For all we know, the phase change to a symbolic written culture just might be the largest singular catastrophe in the standard SQ sequence.

        Why why wh

      • What, then, could an SQ +50 Superbeing possibly have to say to us?

        Nice doggy!

      • What, then, could an SQ +50 Superbeing possibly have to say to us?

        I don't know, but my cats aren't even as smart as dolphins, but I like talking to them anyway. Sometimes they do seem to understand too.

        • What, then, could an SQ +50 Superbeing possibly have to say to us?

          I don't know, but my cats aren't even as smart as dolphins, but I like talking to them anyway. Sometimes they do seem to understand too.

          That is only an act, they see you talking to them as a weakness and will take advantage of that to kill you and get at the food.

    • The one beacon we have triggered repeatedly is nuclear explosions....
      If the thousand or so tests the US did in the 1945-1996 period did not get anyone's attention, what else would?
      When we started monitoring for the Partial Test Ban Treaty, we noticed unexplained gamma bursts from off planet:
      https://en.wikipedia.org/wiki/Vela_%28satellite%29 [wikipedia.org]
      If all the EMP and gamma we tossed around developing and testing nukes did not get someone's attention, I Love Lucy reruns and America's Top 40 hardly stand a chance...

    • It's the one life we know exists, if we find aliens with a totally different physiology or totally different technology that's nice but we have no idea of what to look for. It's unlikely that aliens expect us to tap into their communications, if they are trying to ping us they probably do it using all possible channels. And we know at least one of them, it's unlikely a civilization that can do what he proposes hasn't invented the radio.

      Exactly. Some form of the OP argument has come up ever since SETI was initiated (usually around the time funding was being discussed, and some brain trust politician asked "You guys find anything yet?"). What I think is important is the core idea around the argument, which is not: "Just because we haven't found anything, doesn't mean it's not there." The core idea is actually to avoid being caught up in the small-minded trap generated by anthropocentrism, which has as its central premise: "Using only the si

    • Which is precisely why SETI works in radio frequencies.

      If we turned our best telescopes on Earth, we would only detect ourselves out to about 10 ly (although I bet that's improved). The only hope we have of finding an ET thus requires them to be deliberately signalling back to civilizations like ours. We assume they would do that in the radio frequencies simply because that's what we'd do.

      Sure, these other systems might be useful, but we can't spy on them. So in the meantime...

    • But it emphatically is NOT the only life we know exists. Look around you. Aside from humans, the Earth is teeming, crawling, swimming and covered in and by maybe a billion different species. That's life as we know it.

      However, out of ALL of those billions of species, only one has ever invented complicated languages or radio, as far as we know. Us. So when we look out there for signals from ET, we are in fact really looking for signals from another us, just like the article says. The problem is, if One

      • A few other primates are close to us, but are a few million years away. What do we have to say to these primates today? Bananas are good. I hurt my foot.In a ten million years when chimpanzees are the current us, what will we have to say to them? 000010010100010101010010000101010010000101010100010100011001010 Maybe the whole universe is talking to us, but we can't relate to what it's saying

      • Then again, even if one intelligent species arose within life bearing solar systems, there must be billions of those out there. After running electricity through conductive elements, radio waves are probably the simplest forms of radiation to generate (a byproduct really of electricity through conduits). It is unlikely that a civilization will make the leap from morse code radio to encoded neutron beams without the discovery of the laws governing electromagnetism. So even if they did send out neutrinos now,

  • Only one? (Score:3)

    by tomhath ( 637240 ) on Sunday September 13, 2015 @10:53AM (#50513663)

    When you consider that there are definitely millions of planets in the habitable zones of their stars within our Milky Way galaxy alone, the possibility that there's intelligent life on at least one of them, right now, is tantalizing

    I'm thinking there might be one under our own feet

  • Get back to us on that... (Score:5, Insightful)

    by PvtVoid ( 1252388 ) on Sunday September 13, 2015 @10:56AM (#50513679)

    ... when we have neutrino or gravitational wave telescopes capable of detecting such signals. Which we don't. Current neutrino observatories are very crude, and we have yet to detect gravitational waves of any kind.

  • Worse yet... (Score:5, Informative)

    by Moof123 ( 1292134 ) on Sunday September 13, 2015 @11:01AM (#50513715)

    While we have been sending radio transmissions for 80 years, the modularion has changed dramatically, which has negative imolications for finding ET, even if they are using our same frequency bands.

    Early on we used FM and AM. Both end up with a strong easy to identify carrier tone. As time has gone one and DSP has become a cheap commodity we moved to more efficient modulations (relative to Shannons's limit). Digital modulations look more noise like and have no carrier as such. GPS is below the noise floor as received due to the energy being so smeared out, and that is from medium earth orbit. Your voice calls are recieved below noise as well in a CDMA system.

    So if ET is similarly good at math, they will have moved on to signals that are similarly noise like and may simply be undetectable. There may only be a 100 year or so window to detect Earth, and similar may be true for ET.

    • Unfortunately due to the inverse square law even our strongest radio emissions are unlikely to be detectable beyond a couple of light years, within which radius there are no signs of civilisation we can see. It's interesting to think about really, an entire civilisation could advance to our level of sophistication, and probably considerably beyond, while being invisible to just about anyone more than a few dozen light years away.

      I'm not saying that's the answer to the Fermi paradox but civilisations of any

      • It is highly likely that they will need more than one 'greeter'.

        The first one is likely to be outright killed.
        The second will be 'examined' for how it functions why it is alive.
        The third might actually get to meet a military interrogator to try to figure out how it can be exploited.

        Wouldn't surprise me if by the time we get to #3, they decide to either stop trying to interact with us or that it would be better to eradicate the infestation of water-bags.

      • Re: (Score:2)

        by Zumbs ( 1241138 )

        I'm not saying that's the answer to the Fermi paradox but civilisations of any sort might simply have a far smaller footprint on a galactic level than anyone imagined, and while explorers could have passed by a hundred thousand years ago, five hundred thousand years ago or ten million years ago and found little of interest, there's no reason to believe they might stop by exactly right now and ask to be taken to our leader.

        Well ... Earth has supported life for 3.6 billion years, and complex life for 600 million years. So, if ET have been investigating the solar system, they would have noticed life and could feasibly have left a probe behind, relaying information to where ever their local hub is. However, interstellar travel is likely extremely expensive, time consuming and yields little more than satisfaction of scientific curiosity, so it is unlikely that advanced ET civilizations would want to commit the expense. Even if we

        • Or, there are enough planets teeming with nonsentient life that one more is barely a curiosity. Or, they really did visit and left a probe somewhere in the Oort cloud but it will take thousands of years to send a message home, assuming home even exists anymore.

    • What we've seen of Earth's RF emissions as time has gone on is that they have been decreasing at an almost exponential amount. Today radio transmissions use so little power most cannot even escape the atmosphere and because they are digital they are almost indistinguishable from noise. But those early transmissions in the 40's, 50's and 60's were seriously powerful. They likely were visible above the sun's radiation and carried quite a distance, in addition being analog they would be very easy to spot.

      What

      • > There very well could be an alien species out there is just discovering radio while having already engaged in interstellar travel.

        You can't be serious.

      • Re: (Score:2)

        by Mr.CRC ( 2330444 )
        So the only thing aliens will be likely to hear is "Breaker one nine, breaker one nine, we've got a Smokey behind exit 12A..."
  • they say: Stop Slashdot Beta or die!

  • Assumptions change and so does technology (Score:5, Interesting)

    by Midnight Thunder ( 17205 ) on Sunday September 13, 2015 @11:07AM (#50513747) Homepage Journal

    The methods we have been using so far have always been based on our own technology level and therefore an assumption that other civilisations will be using the same methods.

    One such assumption was sensing infra-red emissions, though the problem there is that a civilisation sufficiently advance may be using technology that has low emissions, due to optimisations. Though, at the same time we need to take note of different technology levels that different civilisations may be using for themselves and those they may be employing for their mutual search of 'extra terrestial' life. What I mean by this, is that they may be employing optimised radio technology, such as lasers and high encryption methods (which may be hard to distinguish from background noise, for us) for communication, but still using wide beam/wide spectrum, unencrypted radio in their search?

  • Well we have been trying to detect gravitational waves and that has been a complete no go.

    So trying to detect alien life via gravity waves will be a little difficult.

    Neutrino modulation well at least we can in principle detect that, though there is no evidence they can be practically modulated for a communication system or that you could in principle make a reasonable detector.

    On the other hand Earth's RF output continues to rise.

  • Nope (Score:2, Insightful)

    by koan ( 80826 )

    We are infants screaming in a forest of wolves.

    That's the truth of the Fermi paradox, the only surviving intelligence is one that's extremely quiet.

    • How would an existing species gain nourishment from another situated at interstellar distances?

      Bad metaphor, I think.

      • Re: (Score:3, Insightful)

        by koan ( 80826 )

        Maybe it's just the machines left over from another species.

        But broadcasting where you are without knowing who is listening, stupid.... that's the only word for it.

      • How would an existing species gain nourishment from another situated at interstellar distances?

        Maybe they just do it for sport.

      • Re: (Score:2)

        by eyenot ( 102141 )

        And also, some babies have been raised on the tenderness of wolves.

    • Re:Nope (Score:5, Insightful)

      by Required Snark ( 1702878 ) on Sunday September 13, 2015 @02:44PM (#50514775)
      Wrong. A conclusion based on ill conceived science fiction.

      Any civilization that can travel between star systems will be so advanced that it will not need to plunder whoever is at their destination. Generally there are two interstellar travel options.

      First, Einstein speed of light restrictions hold, and it takes a minimum of hundreds of years to make the trip. Maybe thousands or more. The technology required means that the travelers can maintain themselves in raw vacuum for very long periods. They have access to power sources that will last as well. If they are going even 10% of the speed of light they have some amazing shielding from the added radiation they encounter from their speed. If they are going slower, 1% or 2% of the speed of light, they have equally amazing biological technology to support themselves and whatever biosphere they need. Same thing for some sort of hibernation. If they have this level of technology, they need nothing from us. Perhaps some raw materials, but those are more easily accessed from rocks and such in the solar system, not down a gravity well. The invasion scenario is ridiculous.

      A similar argument holds for FTL travel. The technology is so advanced from our point of view it might as well be magic. There are one or two speculative models where FTL works under the Standard Model of physics, but they require exotic matter and mind bending abilities over matter and energy. Any technology beyond the Standard Model is ever more mind bending. Magicians need nothing from us.

      The conqueror models is a projection of human history into space. It doesn't hold over interstellar distances. The distance scales and radically different physical environment of interstellar space invalidate any reason for an invasion.

    • Re: (Score:2)

      by Mr.CRC ( 2330444 )

      Alternatively, civilizations may tend to move inward rather than outward once they develop AI and evolve into virtual life forms inside computers. They may back themselves up at a variety of locations within their solar system. If they do still find the inspiration to travel to the stars they will not be doing so for conquest, but rather curiosity. Since they are no longer sentient meatloafs, they won't need so much mass of food, water, air, etc. to put into their starships. Thus, much smaller craft cou

  • The RF era (Score:5, Interesting)

    by PPH ( 736903 ) on Sunday September 13, 2015 @11:31AM (#50513833)

    For most advanced civilizations, this may turn out to be pretty short. Between the discovery of radio and the development of efficient (below the noise floor) methods of modulation, this era may last a few hundred years. So if we are looking for inadvertent radiation, the probability of seeing it must be reduced by this factor.

    The latency problem: Any sufficiently advance civilization will certainly understand the latency problems involved with communications at the speed of light. They might set up a beacon to advertise "Here we are" with no expectation of receiving an answer. But then again, probably not. They might run into the same problems we do with such 'science'. Funds will be better spent elsewhere, so why bother with the gigawatt beacon?

    One possibility: A sufficiently advanced civilization might develop the technology to generate wormholes. Not big enough to physically traverse (due to the energy requirements). But large enough through which to inject photons. And if they can pop them open in the vicinity of candidate solar systems, they could find us in a reasonable (compared to light speed communications) time. So, they've found us. The next step would be to pop open some wormholes where we could actually 'grab' one, observe it for an intelligent optical signal and return one of our own. That would be a useful, two way, low latency link.

    We don't have to understand the physics of how one goes about generating such tiny wormholes. Or aiming them at remote points in our universe. All we have to do is figure out how to detect one, confine it and couple it to optical instrumentation.

  • I like the idea of some religions that there are gods, but they don't generally interact with mankind because we are smelly, coarse savages, filled with anger, lust and stupidity. I think if there is intelligent and technologically advanced life out there, they have more sense than to contact us.

  • One day, scientists and their followers will feel like complete idiots, when it becomes obvious aliens have been here all along.

    Citation#1: US presidents have known about UFOs here on Earth, even seen them:
    https://www.youtube.com/watch?... [youtube.com]

    Citation#2: If 200+ NASA, Ex-Military, Ex-US government high ranking employees coming forth and willing to testify before congress isn't enough for you, then your mind is too closed: https://www.youtube.com/watch?... [youtube.com]

    Citation#3: How many pilot witnesses with radar evidence

    • Is that you, the Alien Guy from the history channel? http://paulabrown.net/history-... [paulabrown.net]
    • You're off your meds again, aren't you?

    • Re:Yes, let's ignore 3Million+ alien abduction cas (Score:5, Insightful)

      by AthanasiusKircher ( 1333179 ) on Sunday September 13, 2015 @07:39PM (#50515971)

      One day, scientists and their followers will feel like complete idiots, when it becomes obvious aliens have been here all along.

      Okay, one can play this game about any widespread "belief." Let's try, shall we?

      One day, scientists and their followers will feel like complete idiots, when it becomes obvious God and Jesus have been here all along.

      Citation#1: US presidents have known about UFOs here on Earth, even seen them:

      Since the beginning of the US, US Presidents have been -- and continue to -- invoke a superior supernatural deity acting on Earth, usually to our country's benefit.

      Citation#2: If 200+ NASA, Ex-Military, Ex-US government high ranking employees coming forth and willing to testify before congress isn't enough for you, then your mind is too closed:

      I can find thousands and thousands of NASA, Ex-military, Ex-US government high ranking employees to talk about how belief in the resurrected Lord Jesus Christ is not only present in the world, but often is responsible for their entire success in life.

      Citation#3: How many pilot witnesses with radar evidence to back it up does it take before you belive that UFOs are real and here on Earth?

      How many miracles certified by the Vatican does it take for you to believe in an almighty deity? (The Vatican employs lots of actual scientists and doctors to certify these too.)

      Citation#4: Is 3 Million alien abductions in the USA alone enough evidence for you, or are you waiting around for a nice round number like 10 million?

      Yes, and hundreds of millions of people around the world believe that bread or a wafer is magically transformed into the body of someone who lived 2000 years ago, and by practicing ritual cannibalism and consuming his body and blood, they will be saved an afterlife of eternal torment. And hundreds of milions of others think the first group is crazy, but they believe in their own tradition pointing to a supernatural god or gods. Etc.

      Don't get me wrong -- I'm NOT saying God isn't real, nor am I saying definitively that aliens have not visited earth.

      But you have to admit that there are good reasons why many scientists have become increasingly skeptical of religious claims in the past few centuries -- largely due to the nature of the "evidence," which always seems a little fleeting or hard to capture in controlled experiments or whatever.

      It is indeed rational to present a similar skepticism to claims like millions of people in the US are supposedly "abducted." How? When? Don't other people in their families notice? Why would aliens be doing this? How many government officials would have to be in on this conspiracy theory to keep it quiet? Why hasn't anyone been able to produce clear evidence of these things?

      Here's the problem -- there are other explanations. You go back more than a century, and rather than alien abductions, people believed in other kinds of noctural weirdness, from incubi to succubi to various other demons or ghosts or fairies or whatever. There are well-known phenomena of sleep paralysis, which occur when your body's motor control turns off, but sometimes the conscious brain is still a little aware. This has happened to me a number of times in my life -- and I've even had dreams and nightmares that correspond to those times, sometimes where I've "felt a presence" or whatever nonsense... but I recognize these things as nightmares combined with well-known physiological phenomena... I don't blame them on aliens.

      Isn't it interesting that all of these "abductions" started soaring just about the time that UFOs and sci-fi stories became all the rage? And the old stories about demonic visitation, etc. just happen to disappear at the same time?

      Humans have an incredible propensity to look for patterns in randomness, and to try to ascribe meaning to phenomena even if t

  • Contact Avoidance (Score:5, Insightful)

    by mtrachtenberg ( 67780 ) on Sunday September 13, 2015 @11:51AM (#50513931) Homepage

    Any extraterrestrial civilization that has survived into interstellar travel is probably willing to invest a great deal of its time and energy into NOT being discovered by us. What could be more dangerous than a species that has learned some technology yet turns every technological advance into a weapon against others of its own kind? And we've been advertising that aspect of ourselves to the universe ever since we discovered radio waves.

    • Professor, what do we know about them?
      We know they're extremely advanced
      technologically... ...which suggests, very rightfully so,
      that they're peaceful.
      An advanced civilization is,
      by definition, not barbaric.

      https://www.youtube.com/watch?... [youtube.com]

    • That's both arrogant and incorrect.
      1. There have been far more technological advances than types of weapon actually used against our own kind (to the extent that 'technological advances' is even quantifiable).
      2. Any extraterrestial civilization engaged in interstellar travel can kick our ass without issue. We're talking about a civilization that has harnessed huge amounts of energy, is highly rational, organized and intelligent. Even if they were peaceful in principle, they would be foolish to not have adva

      • > we are currently just a bunch of poop-flinging monkeys learning how to use a stick to catch some ants.

        Yes, and most people probably want to avoid the poop. It's far easier to cause damage than to win.

    • Re: (Score:2)

      by cfalcon ( 779563 )

      Wait, they are super advanced, but they hate anything that evolved in any but a set of totally noncompetitive circumstances? What you just said applies to *every species on earth*. So because of the circumstances of our evolution, they write off every animal on the planet, humans included, as fundamentally evil?

      The fuck?

    • Yeah no kidding. Take a step outside yourself for a moment and try to see us through extraterrestrial eyes: We treat our own kind like absolute crap. Under pressure, which is when you find out what someone is really like, you discover that we're still mostly animals. We kill each other for stupid reasons. There's a whole list of things I'm not even going to get into here, but the bottom line is, in my opinion, any extraterresttrial civilization that is more advanced than we are, probably is going to avoid u

  • Neutrinos and gravitational waves? That's so 20th century. We should be looking for quantum signaling and psi emissions! After all, our devices for detecting quantum signals and psi emissions are just as advanced as our devices for detecting neutrinos and gravitational waves!

  • "Unsurprisingly, we're looking for exactly the types of signals we're capable of sending, but what if that's totally wrongheaded? "

    What? No alien 'I love Lucy'? Perhaps they are blind and deaf and just use 'feelies' or 'smellies'.

  • The transience of "broadcast signals" (Score:4, Informative)

    by jeffb (2.718) ( 1189693 ) on Sunday September 13, 2015 @12:27PM (#50514087)

    One aspect of the Fermi Paradox is the assumption that "civilization as we know it" necessarily broadcasts a huge amount of information-bearing electromagnetic radiation, and that more advanced civilizations will broadcast more. From a modern perspective, this seems silly.

    A signal recognizable across interstellar distances represents waste. It's energy that's spent without reaching its intended target. One aspect of "advancement" is reducing this waste -- improving modulation schemes, encoding efficiencies, and transmission techniques to minimize wasted power.

    A signal recognizable across interstellar distances also represents lack of diversity, or wasted capacity. If you're using a certain chunk of spectrum to broadcast a signal recognizable across light-years, you're not getting as much capacity out of that chunk as you could by using it for a bunch of geographically localized broadcasts -- for example, by broadcasting separate programs to each of 100 individual square miles within a 10-mile square, rather than one program for the entire 100-square-mile area. Take this idea a bit further, and you see our current cellular networks. From space, their signals would sound like noise.

    It seems to me that the natural signal of a civilization like ours is a pulse of EM broadcast, lasting perhaps a few decades, then going silent or becoming indistinguishable from noise as we move to more localized and more efficiently encoded transmissions. If nobody happens to be listening in our direction during the right interval, brief compared to technological civilization's lifespan, they could easily miss us completely.

    • Signal strength drops by the square of the distance, so if the closest possible earth-like planet with a civilization is say, 5000 light years away (about 5% of the distance across the Milky Way), is a reasonable amount of power, say 1 megawatt, 1 mile from that earth-like planet going to be detectable here on Earth after intersteller dust and gas absorption?

      Would Infra-red transmission get through longer distances even better between planets?

    • Re: (Score:3)

      by pz ( 113803 )

      The counter-argument to all of the broadcast hoo-ha is that when you're standing a gazillion miles away from Earth, you're going to be receiving ALL of the broadcast signals on a given frequency. Do you really think that's going to be indistinguishable from noise even if you know what frequency to look at?

      We aren't going to find ET by looking at inadvertent EM spill. We are going to find civilizations that want to be found and are sending a bright, intentional signal that has characteristics that make it

  • Our species has not existed for very long, maybe a few hundred thousand years. Only in the last hundred years have we even begun playing with electromagnetic waves. Our experts consider this feasible. We need to look closer at science fiction and start speculation on technology. We have to assume that faster than light communication is indeed possible if not outright travel.

    There are millions of planets out there that do have life on them. Jungle worlds. How do two species communicate over such large distan

  • If I was an alien sending signals I would send the easiest to detect, like radio, or light.
  • Comment removed based on user account deletion

  • I image that about 1/2 of those civilizations are technologically *less* advanced than us. Perhaps we should try flag semaphore or smoke signals.

  • Needle in a haystack (Score:4, Interesting)

    by eyenot ( 102141 ) <eyenot@hotmail.com> on Sunday September 13, 2015 @02:02PM (#50514489) Homepage

    Let's admit it, we don't even know what we're looking for. I mean that in the broadest, most philosophical sense. We say we're looking for E.T. but there's no way we can look for something too dissimilar to ourselves so we end up looking for ourselves as an end result.

    As many here have pointed out, the RF era may only last a short while. It would be a pretty heady coincidence if we did receive signals from that era from an exo race just at the time we're spending (wasting?) our time looking for such signals.

    Consider the law of inverse squares. It doesn't take very many light-years for a radio signal to become a whisper. People are talking about compressed and distributed radio that is indistinguishable from background noise. I haven't seen many people offering a similar argument for AM and FM - not very far away (about 120 light years from some things I'm reading) and the same thing happens to even very strong broadcasts from Earth.

    So unless we're really, really blowing on the dice, here, we don't have much hope of finding something this way. We're talking about the coincidence of not only E.T.'s radio era and our listenership, but also the coincidence that E.T. lives extremely, extremely close to our neighborhood. Two coincidences at once, playing out to our whims? I doubt it.

    But think about what we broadcast that doesn't get attenuated so easily. Think about our space probes.

    Surely even the most technologically advanced races have to give up trying to receive propagating radio signals beyond a certain distance. But space probes always stay the same size (don't quote me on that, cosmogony and quantum mechanics experts) so even if they aren't going at the speed of light, they stay detectable across time and space.

    I'm sure it's far easier to pick up a tiny, tiny little pinprick of metal and electrical energy (valuable things in space) for an advanced race than it is to find random signals amidst the background noise of the universe.

    Maybe we should learn to apply a similar technology. Maybe we need to develop "sensor arrays" that can quickly and easily detect artificial satellites drifting through space. For all we know, several have gone through our solar system since the advent of, say, radar, and we don't know it because we're not really looking or don't know how to look properly.

    If we're so certain that there are exo races out there that have lived in an advanced state for long enough that by now their intelligent creation of radio signals is reaching us, then it's just as safe to assume that by now their space probes are reaching us as well. Voyager is escaping the sun at 38,500mph. Light travels at roughly 300,000mph. So this dramatic leap in assumption is simply a magnitude of ten.

    Considering the milky way is 100,000 years across, I think it's okay to play with a magnitude of ten in terms of light years when asking ourselves how big of a "neighborhood" we live in. It's like saying maybe our neighborhood is the size of our subdivision and not just our cul de sac.

    When you take all of this into consideration, it looks actually very silly to spend time looking for radio signals. It makes looking for radio signals seem like a sideshow game that some people just happen to be distracted by.

    Meanwhile, our solar system could be bristling with tiny little space probes that we ignore because we haven't learned how to effectively differentiate them from rocks.

    Maybe that's because we really actually fear the universe. Our biggest concern about exo objects is space rocks because we're so afraid that a big one is going to slam into our planet.

    It reminds me that a lot of people have argued that we should be learning how to mask our signals and to stop sending out calling card broadcasts in the hope of gaining an audience.

    • Light travels at roughly 300,000mph.

      ERR_INVALID_UNITS. Light travels at roughly 670,000,000 mph.

    • Re: (Score:2)

      by lgw ( 121541 )

      We do know what we're looking for: aliens who want to contact us, and have tuned their signal to be easily detectable by us. We're not going to see anything else, after all.

  • Encryption (Score:3)

    by Lennie ( 16154 ) on Sunday September 13, 2015 @02:04PM (#50514503)

    If they are only a little bit more advanced then our civilization they've probably encrypted all their communication, maybe even encoded it in such a way that it will be hard to distinguish from cosmic noise. If they don't want to be found, they'll be hard to find.

  • "having only been broadcasting electromagnetic signatures visible by an alien civilization for around 80 years"

    Not really, none of our signal went beyond a few au for most signals, and a few hundred au for most others. The reason is simple most signal were not very directional, and propagated at some point in 1/r^2, even if it is a cone rather than hemispherical. So for big r the r^2 gets bigger and you get a signal amplitude which is below the intergalatic noise for that frequency.

    There are about only
  • You mean the giant sign on my roof pointing up that says "I'm ready to be probed" isn't likely to attract any aliens?

  • I was of the understanding that current radiotelescopes could not pick up a regular broadcast signal of the type that is sent by commercial transmitters but that the signal would have to be much more powerful and concentrated, intentionally sent for the purpose of detection from another planet. I suppose that I was wrong?

    Secondly, what benefits would a gravity or nuetrino have over EMF for communications? If it was so great why wouldnt be we be using it? How would you create a gravity or neutrino communicat

  • Why wouldn't an ET leave a big message that was hard to miss, like, say, a moon? Or even better, a big pyramid in the middle of nowhere? That would be kind of hard to miss, wouldn't it?

  • So I doubt we'll ever detect life "up there". Which is only in one direction, up; see my signature. I have tested moonlight and it makes things colder (i.e., it was warmer in the shade of the moonlight), so it's definitely not reflected sunlight. If it's not reflected sunlight? Well, then, we need to recognize our preconceptions and test and verify them.
  • So far human communications are based upon a signal traveling along a path. In an advanced culture that may no longer exist. Quantum mechanics is weird enough and just maybe information can be made to appear at a target place without traveling in the physical universe. Obviously we could not detect something like that.
  • Maybe we're not just looking the wrong *way*, but in the wrong *place*. Maybe *extra-terrestrial* isn't broad enough! Maybe we'll find life other than what's here on Earth in a much broader domain, i.e., maybe we should be looking for *extra-cosmic* life, in other words, life outside our cosmos! How? In the fabric of mathematics itself. Max Tegmark has suggested (and indeed made a career of) speculations that *our* universe is mathematical (he posits the existence of mathematical structures that might

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