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SETI: Going Deep with the Data Search

What Breakthrough Listen is calling the most comprehensive SETI search to date is now in the books, or at least, the journals, with results accepted and in process at Monthly Notices of the Royal Astronomical Society. Here we are in the realm of data reanalysis, using previously acquired results to serve as a matrix for re-calculation, with the catalog produced by the European Space Agency’s Gaia spacecraft as the key that turns the lock.

No signatures of extraterrestrial technology were detected in the two analyses produced by Breakthrough Listen in 2017 and 2020. The data for these efforts come largely from the Green Bank Telescope (GBT) in West Virginia and the CSIRO Parkes Radio Telescope in Australia, with a focus on 1327 individual stars. Results were published by the Breakthrough Listen science team at UC-Berkeley, and the choice of targets was telling. The search homed in on relatively nearby stars within about 160 light years of the Sun, under the assumption that less powerful transmitters would be detectable the closer they are to the Earth.

The new analysis of these results has been produced by Bart Wlodarczyk-Sroka, a masters student at the University of Manchester (UK) and his advisor Michael Garrett, working with Berkeley SETI director Andrew Siemion. The Manchester duo realized that when one of the large telescopes was pointed at an individual target, the observation also took in a wide range of background stars. This fact meant that stars much further away could be considered if we could make a determination about their distance.

The Gaia catalog measures the distances to over a billion stars. Wlodarczyk-Sroka and Garrett realized that Gaia now gave them measured parallaxes and inferred distances to stars that were found in the full width half-maximum (FWHM) of the main beam of the telescopes used for the Breakthrough Listen observations. FWHM specifies the angular width of the main beam — think of it as the width of the frequency range where less than half the signal’s power is attenuated. Although not targets of the earlier campaign, these numerous stars were available in the data, previously ignored because their distances from Earth were at the time unknown.

Image: This is Figure 1 from the paper. Caption: . An optical colour image of the stellar field centred on HIP109427 from the Pan-STARRS DR1 z and g broadband filters, showing the extent of the FWHM for the GBT L-band and GBT S-band receivers, circled in red and white respectively. 46 sources with geometric distances calculated from Gaia parallax data are marked with green crosses. Credit: Wlodarczyk-Sroka. Garrett & Siemion.

The Gaia information allowed the researchers to select targets out to 33,000 light years, all found within the original observations, thus expanding the number of stars examined from 1327 to 288,315. Their distance would mean that as the range increased, only more powerful transmitters would be visible to the telescopes. The sample takes in not only many main-sequence stars but extends to giant stars and white dwarfs as well.

Andrew Siemion comments on the significance of the effort:

“This work shows the value of combining data from different telescopes. Expanding our observations to cover almost 220 times more stars would have required a significant investment of our telescope time, not to mention the computing resources to perform the analysis. By taking advantage of the fact that we already had radio scans of stars in the background of our primary targets, and by reading their positions and distances from the Gaia catalog, Bart’s analysis has extracted additional information from the existing dataset. Work like this gets us one step closer to the goal of knowing the answer to humanity’s most profound question: Are we alone?”

Given that the only qualifying criteria for the stars in the new study is that they were within the view of the original observations (i.e., within the FWHM of the telescope beam), the range of stellar types is broad, and this marks the first time scientists have been able to place limits on the prevalence of continuous extraterrestrial transmitters on the basis of spectral type.

In earlier studies, no evidence was found of continuous transmitters associated with stars systems within 50 parsecs of the Sun, given power constraints as explained in the paper:

Both Enriquez et al. (2017) and Price et al. (2020) find no evidence for continuous (100% duty cycle) transmitters associated with the nearby (d < pc) star systems observed. This includes directional transmitters (e.g. radio beacons) directed at the Earth with a power output equal to or greater than the brightest human-made transmitters (e.g. a canonical Arecibo planetary radar-like system with a gain of 70 dB and a transmitter power of ∼ 1 MW). To detect a non-directional isotropically radiating antenna, the transmitter power must be ∼ 1013 W (around the current energy consumption of our own civilisation).

We don’t know if any civilizations in this range are broadcasting at all, but the data are consistent with the statement that fewer than ∼ 0.1% of the stellar systems within 50 pc are using these types of transmitters to contact us. The new work now moves well past the nearby sampling of stars, while factoring in the decrease in sensitivity at larger distances. At 100 to 200 parsecs, for instance, fewer than 0.061 such transmitters can be present, given the same power constraint. We have no candidate signals, but we have hugely widened the scope of the search and tightened the numbers. Wlodarczyk-Sroka comments:

“Our results help to put meaningful limits on the prevalence of transmitters comparable to what we ourselves can build using 21st century technology. We now know that fewer than one in 1600 stars closer than about 330 light years host transmitters just a few times more powerful than the strongest radar we have here on Earth. Inhabited worlds with much more powerful transmitters than we can currently produce must be rarer still.”

Setting constraints is not glamorous work, but it’s how we go about building information. We’ve seen the same phenomenon in exoplanet studies. At Proxima Centauri, scientists progressively drilled down by radial velocity research, first eliminating large gas giants and then progressively smaller worlds as possibilities until finally uncovering Proxima Centauri b, at about Earth size. All the patient data analysis builds the structure needed to arrive at eventual conclusions. When it comes to SETI, we’re learning, bit by bit, what is not there, and also clarifying how much remains to be explored.

As just one case in point: What if the beam is not continuous? Should we expect it to be? See SETI: Figuring Out the Beacon Builders for more on ‘Benford Beacons,’ a topic of frequent discussion in these pages.

The paper is Wlodarczyk-Sroka et al., “Extending the Breakthrough Listen nearby star survey to other stellar objects in the field,” accepted at Monthly Notices of the Royal Astronomical Society (preprint).


Comments on this entry are closed.

  • Ron S. September 3, 2020, 14:33

    Statistic analysis can yield some impressively precise numbers that are almost entirely meaningless. This is not to say their number are wrong, only that they tell us nothing we didn’t already know: transmissions by a motivated and adept ETI to us of a particular format, frequency and power at a particular time is sufficiently rare that it remains undetected.

    We have vastly more and better data for the mass of a photon and we still cannot say with certainty that it is zero. We can say that it is constrained to be exceedingly tiny within an interval that includes zero. So it is with ETI. We don’t know and the present work sheds little or no light on the question.

    Although I am perfectly fine with the ongoing search and improved data analysis those published numbers are uninformative and potentially misleading.

  • Alex Tolley September 3, 2020, 17:53

    In some ways it is interesting that exoplanets seem be be more common than originally thought, whilst transmitting technological civilizations, far fewer. Which way will the prevalence of life go?

    As we continue to come up with no signals that we can detect, we are forced to abandon the galactic club as an idea (at least using transmissions we can detect fairly easily) and either fall on the side that we are alone (or at least very rare), or that civilizations are avoiding detection.

    My personal use of Occam’s Razor suggests the former hypothesis is most likely the correct one. I just hope that life proves far more prevalent and detectable.

    So we will continue the SETI experiment, examining more stars and galaxies, using more approaches to detect ever weaker signals in a ever widening em band and even other transmission modes. Maybe the [lack of] detection of artifacts will be a useful orthogonal approach to determine is ETI is out there.

    If it looks like the galaxy is empty of civilizations, then if the Great Filter is behind us, we might look forward to advancing into the galaxy and creating those civilizations which in time will provide humanity with all the rich cultures evolution will create to converse with. Perhaps we will engage in a program of uplift if we find species with potential. Perhaps we will create new branches of post human species. These would definitely be more enticing and optimistic futures than a galaxy of cowering civilizations, afraid to make themselves known for fear of a predator civilization, which in turn would stifle our own hopes for a bright future.

    • tesh September 4, 2020, 6:58

      I quite enjoyed the Uplift books and interestingly were they not a mix of the cowering/oblivious entities as well as with an uplift component?

      I wonder if we will go down this road as a prelude/pretext/byproduct of trying it on ourselves, i.e. will we see if we can enhance the cognitive and adapt the physical abilities of apes first before trying it on ourselves?

      • Alex Tolley September 4, 2020, 12:23

        Did you not watch any of the “Planet of the Apes” movies? ;) Clarke had cognitively enhanced chimps in one of his short stories (“An Ape About the House”). But assuming a chimp will never have a temper tantrum is dangerous. I wouldn’t risk such a creature in a domestic situation.

        I have no doubt that we will attempt uplift of terrestrial animals. Their brains and biology are far more suited to this than aliens. My guess is that chimps can be made more intelligent with quite simple genetic engineering, e.g. tweaking genes to increase brain cell replication. Add in prostheses to allow vocalization like Hawking, and one might achieve such an uplift quite soon. Whether it would be moral is an issue I leave to others. Another possibility is to recreate Neanderthals which are even closer to out line.

        I don’t think we want to uplift more than a few species, and we certainly won’t want to risk some sort of “Planet of the Apes” replacement of humans, but I suspect the desire to communicate with another species is so strong that we will work with what we have on Earth, unless a friendly alien comes and visits before then.

        • tesh September 5, 2020, 5:01

          Leaving the whole Frankenstein issue aside, this bit is unlikely to be easy:

          ” e.g. tweaking genes to increase brain cell replication. ”

          For me this bit seems to be a far from easy task to accomplish – at least as far as achieving the desired ends. I wonder how you would go about it? Do you start with organoid systems first (based on IPS/EPS technology) to get the desired outcome and then to embryos and then to actual implantation? Even picking what to tweak is far from trivial. Which cell type / types? I guess there is a wealth of information out there already regarding human development and disorders that could yield clues…

          The next issue (would need to come first i guess) would be the why for doing it and then the how you would go about finding a movement/organisation to support the endeavour. I guess the remit of the funding bodies are sufficiently grey to allow a lot of the research if framed correctly. The struggle to get the general public to support space exploration after all has been anything but easy so something even more abstract and morally grey would be an even trickier ask.

          Maybe it is our moral duty to uplift. The planet currently has only one voice (however fractured). Should we not give others a voice also – or is that pointless because we would deem them less than human…?

          • Alex Tolley September 5, 2020, 15:44

            Just using the human version of the FOXP2 gene is needed for speech and language. It is a transcription factor than controls other genes. It is known that humans have just an extra neuron replication event compared to chimps, increasing our brain size. Development is more like baking, small changes in ingredients or conditions canresult in large differences of outcomes.

            As to giving voice to other species, one should be concerned about nth order effects that do not benefit the animal. We need to be careful when trying to play at being Gods.

            • Robin Datta September 6, 2020, 16:38

              Many modifications contributed to human speech. Brain modification is one of the important ones.

              The modification of vocal tract anatomy was also essential. Upright stance moved the head around 90° to alignment with the new horizontal, resulting in a similar angulation of the oral cavity with respect to the oropharynx. Control of fire and cooking of food resulted in less mastication and a decrease in size of jaws and teeth, with narrowing of the oral cavity.

        • Robin Datta September 6, 2020, 15:30

          “But assuming a chimp will never have a temper tantrum is dangerous. I wouldn’t risk such a creature in a domestic situation.”

          domestication of humans
          was perhaps as important as intelligence in achieving sociality and civilization.

  • Andrew Palfreyman September 4, 2020, 2:16

    I have no problem with a continued SETI effort, but some perspective is in order. We have been aware of electromagnetism as a communications modus for less than two centuries, and yet the upper limit on putative technologically-savvy civilisation in this galaxy is on order eight billion years. So don’t be surprised to discover that there’s something better than radio or lasers.

  • AlexTru September 4, 2020, 3:10

    Rhetorical question:
    When SETI (in common sense) will recognize negative result of their searches?
    The Answer is – never!
    So as time is passing SETI is moving away farther and farther from science.

    • Harold Shaw September 4, 2020, 18:46

      This is a narrow view of SETI’s role. SETI can be viewed as a scientific experiment but it is first and foremost strategic game play. A rational species that wants to expand into the galaxy must do SETI. There will always be strategic value in SETI.

      • AlexTru September 5, 2020, 1:52

        Yes, I agree that rational species should sometime do SETI, but in same time I suppose that rational species should analyze obvious negative results of searches and make realistic conclusions , sorry I do not met realistic conclusions from fruitless searches that are continue more than 50 years.
        So, I afraid, that modern SETI is not grounded on science anymore, but it is the type of new religion.

        • Harold Shaw September 5, 2020, 13:46

          You would have a valid point if potential ETI behavior were as predictable as natural phenomenon. The tiny sample size of searched star systems would provide meaningful negative results. Potential ETI behavior doesn’t exist in the realm of hard science. It is in the realm of messy soft science. A negative result from a survey for communistic governments in North America can not be used to extrapolate for the world.

          Soft science, especially behavioral sciences, are messy and can be frustrating to navigate. They aren’t a religion. What you are offering is run of the mill hard science chauvinism. Like it or not, SETI is never going to fit precisely into hard science experimental paradigms.

          • AlexTru September 6, 2020, 3:05

            You wrote:

            if potential ETI behavior were as predictable as natural phenomenon

            Do you mean that ETI it is unnatural phenomenon?
            Unnatural – it is research area of theology…

            Me too strongly believe that ETI must exist somewhere in the Universe, but in same time I completely resist the modern SETI approach – I also believe they will never find anything if will continue with current methods (that seams to be the case), because they intensively collecting data, but deny to make serious analyze and conclusion from collected SETI data.

            • Harold Shaw September 6, 2020, 10:44

              Word play can be fun but it isn’t an argument. By ‘predictable natural phenomenon’ I clearly mean things like stars or chemical reactions as opposed to the behavior of individuals or people.

  • ole burde September 4, 2020, 6:05

    As evidence is acumulating for the lack of tecknologic civilsations ( and perhabs later the lack of microbial life ) in a fastgrowing distance from earth , it wil soon be time to face the most important decision humanity can ever take : should we decide to SEED life whereever we can ? Is this the Great Mission which can bring us all together in a stable global civilisation , like the building of Pyramids seems to have stabilised several ancient cultures ?……anyhow it wil sadly take a long time to terraform ANY planet , so perhaps we should get started as soon as possible….

    • ljk September 4, 2020, 9:54

      What this is showing a seeming lack of technological civilizations that have built really powerful transmitters that also happen to be signalling in our direction during the incredibly narrow window that humanity has been able to listen and look for ETI – and an even more narrow window of when humans were even able to grasp this concept and do anything about it. I could go even one level more and add the narrower window when humans had the proper means and open enough minds to properly search for such alien species.

      I am more than a bit skeptical of a Star Trek style galaxy. I tend more towards Stanislaw Lem’s philosophy on the true nature of alien beings – which means they will be ALIEN, not humans with a few variations.

      Thus our current methods will have to hope for either a lucky break in detecting a random signal, or having an ETI that is deliberately transmitting to us for some reason. In the latter case, if they want our attention they will be making sure the signal is not only a strong one on many frequencies and wavelengths, but also contain the means for us to understand it. Look back again at the very narrow range of our history when we would be able to detect and comprehend such a signal from the stars.

      Obviously it would be preferable if we could build SETI stations in space, where they can be huge and also shielded from terrestrial noise, such as on the lunar farside.

      It would be even more preferable if we could start launching interstellar probes to the stars. We could do it with Orion style vessels, but we killed that plan in the 1960s and no one seems very eager to resurrect it. There is Breakthrough Listen, but so long as we keep relying on a ridiculously powerful laser to get those little probes to Alpha Centauri, it will remain yet another idea that is decades if not centuries in the future – which almost means never.

      However, I will NOT sit on my hands and see us do nothing. We will search with what we have and improve these techniques and our knowledge from there. We could miss something while others claim we need to wait for things to improve.

      • Alex Tolley September 4, 2020, 12:10

        It would be even more preferable if we could start launching interstellar probes to the stars. We could do it with Orion style vessels, but we killed that plan in the 1960s and no one seems very eager to resurrect it.

        For good reasons, I think. Even allowing for nuclear fusion rather than atomic bombs, the ship designed to reach Alpha Centari would weigh 400,000 tons and take 133 years to reach its destination. The cost would literally be astronomical, and that would only allow a single star to be surveyed.

        Costs must be kept a low as possible, which means miniaturization. Breakthrough Starshot may be too extreme to work, but it is going in the right direction, IMHO. The Chilean plateau phased laser array is expensive, but nothing like the cost of launching the needed mass of the Orion-type spacecraft.

        If we are going to build huge spacecraft that mass on the same order as Nimitz class carriers, either the cost of access to orbit will have to be reduced by many orders of magnitude, or more likely, they will be built in space using space resources and a large infusion of autonomous robotic labor. Neitheir of these 2 scenarios looks to being achievable anytime soon. I wish it were otherwise, but we need to be realistic.

        If we send a kilogram class probe at 0.1c using sails and beamed energy, we can hope to deliver such probes to many stars. They might be able to solve the communication issue by transmitting from the gravitational focus of the target star. The wait for results may be long, but they seem achievable. In the meantime, as technology develops, we may be able to create ever faster vehicles using better propulsion methods. But if not, those “slow” probes can still get the job done, as long as we still have operational listening stations.

      • Alex Tolley September 4, 2020, 19:00

        It seems to me that this is getting seriously close to using the same arguments as believers in teh supernatural:

        1. You are not praying hard enough
        2. X will not answer until you truly believe in X
        3. X cannot hear our vocal exhortations because we have not built a big enough building (e.g. cathedral) or concentrated enough vocal exhortantions for X to receive us
        4. X works in mysterious ways, that is why we do not apparently hear from X
        5. We need more funds to send our exhortations out more loudly to X

        And so on, and so forth. Non-believers will simply say that there is no X. Believers will correctly say that is unprovable, and that X has many ways to communicate with us. If we are not careful, 2 centuries from now, Frank Drake will become revered as a prophet.

        At some point, all the probabilistic equations for ETIs existence will stumble on continued lack of response. The various arguments explaining the Fermi Question/Paradox(how many are there to date?) will be no better than religious arguments. Scientism pretending to be science.

        Ancient, billion year old ETI civs are indistinguishable from supernatural beings. Why should either have more probability of existing? Like Black Swans we may have to visit the spatial equivalent of the antipodes to find any ETI. They will not make their presence known to us if we do not go. To my mind, that means that at some point in teh future, the current methods of SETI need to just shut down and focus on some other means, like funding star probes when they become affordable. It may mean that humanity has to wait millions of years for a definitive answer, but that may be the nature of the beast.

        • Harold Shaw September 5, 2020, 13:59

          I don’t think ljk comes anywhere close to using the same arguments as believers in the supernatural. The range of potential ETI forms and behaviors is immense. We can’t make any predictions based on the quick peak humanity has conducted. Their argument that we have only scratched the surface of potential ETI landscape is sound reasoning. We can only rule out a certain population density for gregarious ETI.

          That being said, your statement that it may take millions of years to conclusively answer the question of whether we are alone in the galaxy is equally sound. But it would be millions of years of persistent SETI.

  • neutrino78x September 4, 2020, 9:11

    I feel like we dont have the sensitivity yet to detect an alien civilization.

    Since we aren’t transmitting continuously (at least not at high power) we have to assume they are not.

    When we habe the sensitivity to detect things like weather/military radar and domestic radio/tv broadcasts, I’ll be much more interested in those results. :)

    • ljk September 4, 2020, 10:41

      It is worse than not having the equipment to search for ETI properly, it is the intelligence, imagination, and will.

      Things have improved since modern SETI began in 1960, when there was a four-year gap between Project Ozma and the next official SETI effort to give you some idea how things were back in the day. However, while we are finally starting to break out of the Radio SETI looking at Earth-like planets around Sol-type stars tyranny, there are still plenty of cultural and intellectual roadblocks keeping us from doing a really meaningful SETI program. I think that many of the folks here who read and comment regularly could change this for the better, if they want to.

      Hint hint hint.

  • Michael Spencer September 4, 2020, 11:54

    Alex Tolley writes:

    “As we continue to come up with no signals that we can detect…we are forced… either fall on the side that we are alone (or at least very rare), or that civilizations are avoiding detection.”

    Or, possibly, that distance precludes detection? Or that our dependence on the electromagnetic spectrum, light included, is primitive, having been abandoned as others march up the technological scale?

    Waxing philosophically: some argue, me included, that physics and cosmology, breathtaking as they are, have yet to provide fundamentally satisfying descriptions of the our Universe; and that the Grand Prize will provide entry to currently unimagined treasures. Among these could be interstellar communication, as well as mastery of huge energy densities. Or not!

    And Paul: you’ve contributed immensely to SETI coverage by including it here among other, more mainstream research. Thank you.

    • Paul Gilster September 4, 2020, 15:50

      Thanks, Michael. SETI has always fascinated me, so I’ll continue to track it.

  • randomengineer September 4, 2020, 14:02

    Since it’s been discussed on previous threads that an unambiguous signal stretching across a lot of light years could be constructed with tech that we’re already on the verge of — that is, enormous shades surrounding a star that can cause starlight to seemingly pulse — then the lack of such a clear “here we are” signal suggests that there are no signals at all. There seems to be no reason to search for ever-elusive and increasingly esoteric methods. Why would aliens advertising their position be coy and select obscure (star trek) tachyon pulses when simple shades that require no broadcast energy would suffice?

    ISTM that ET would construct the optical shade broadcast aligned along the galactic plane as a locator, and civilizations seeing it and then knowing where to point their unidirectional tachyon pulse receivers (or whatever) would be able to receive any actual “hello galaxy” data.

    • Harold Shaw September 4, 2020, 18:34

      An ETI’s personality and motivations will have a greater impact than engineering on the shape of their communication strategy. You are arguing that the only possible personality is gregarious and motivation is to be seen by everyone. Everywhere we look in the natural world we see communication strategies tailored to the unique motivations of individual plant and animal species.

      Why is it improbable that an ETI would tailor its communication strategy to be selective?

      • randomengineer September 4, 2020, 21:28

        Well I was really hoping that “here’s a bright light so y’all know where to look, but you’ll have to speak tachyon to join the club” was a reasonable bridge between the two usual factions. The first one assumes there’s a signal out there somewhere because as you put it, ET is in fact gregarious and wants to be found. The second assumes we see nothing because ET doesn’t want to be found; he’s either running an ET club or there are bad ETs out there to avoid.

        The entire premise of SETI is the first scenario. So let’s run with that. My take is that if ET wants to be found, then ET is bound to do the easiest and least energy wasteful thing to be noticed. ET isn’t going to blow huge energy budgets on tight beam radio aimed willy nilly when big shades on a nearby star along the galactic plane are energy-wise cheap and easy (comparatively.)

        For all we know, Tabby’s star was once such a beacon and long after the civilization died out, the local Oort cloud pulverized the shades to yield what we see now (the IR signature, last I heard, suggests it ain’t dust.)

      • DCM September 5, 2020, 4:31

        Seems highly probable they would.

    • AlexTru September 8, 2020, 0:53

      I suppose that blocking (Steering) of high energy electromagnetic stream requires technology and energy level may be little bit less, but comparable with requirements for EM transmission.

      • randomengineer September 8, 2020, 10:57

        I’m not sure how making a star level of EM source energy would be comparable to orbiting objects around a star; can you please elucidate? I want to be sure I understand what you said.

        • AlexTru September 9, 2020, 13:26

          Is you mean some huge sized object orbiting around star on kepler orbit, the energy required to do so, can be somehow calculated taking in account mass of object and energy required to put this mass on the orbit… the size of supposed object should be comparable with planet size, data rate will be lower than time required to make full turn around orbit. etc….
          I am too lazy to continue with this argumentation.
          Present moment we can hardly can find distant planets using the method you propose, let detect the modulating signal, may be it is not a real planet but modulated ETI message…
          None can explain why ETI should send any message at all…
          I afraid the only argumentation – I want …

  • Michael Fidler September 4, 2020, 23:35

    The more I read about neutrinos the weirder they get. Could this be the way ET communicate and may there be an encoding method we may not fathom?
    Ask Ethan: Do Neutrinos Always Travel At Nearly The Speed Of Light?

    Then there is the quantum entanglement, which we do not really understand, how about Neutrino entanglement?

    What about localized communications, where you have to be in the right place at the right time to receive it. Musk’s StarLink with 42,00o satellites may pick up unusual signals because of the huge area of coverage…

  • Kamal Ali September 5, 2020, 3:48

    We cannot fathom the size of the space and time we are looking at here.
    There could be an Arecibo every 1000 LY and we would not see it.
    There could have been a million civilizations each of them transmitting directly in our direction for a random 100 year period spread out over the 13B lifespan of our galaxy and given that we are only watching for 40 years, the probability of us seeing *any* of them is miniscule. It is not only space that is huge, but time is huge too. We have been looking for a miniscule amount of time, and even in that time, we are far from monitoring all the stars in our galaxy. And thats not even considering that electromagnetism has been developed in the last 150 years so other ETI may be using completely different things that may take us thousands of years to discover. To give up after only looking at such a small percent of stars after only 40 years only tells me we do not understand the magnitude of the search space we are dealing with.

    • Alex Tolley September 5, 2020, 15:49

      You make the same assumptions that I see repeated over and over again. Areceibo is used as a peak (not overtaken by China) reference to make calculations. We are so removed in development time from any ETI that we can expect their technology to be vastly superior to ours. Indeed we can imagine far more powerful technologies that we might have in a cosmic eyeblink. Therefore, ETI signaling would be obvious, not constrained by technology we currently have and that is being obsoleted as we speak. IMO, @randomengineer is far more logical in his thinking about this.

      • Harold Shaw September 6, 2020, 10:57

        You and @randomengineer are making the black and white logic fallacy that only the most extreme cases are possible; if potential ETI are willing to communicate or be seen they will be fully invested, willing to communicate with or be seen by everyone and anyone. Try this logic with any behavior that exists as a spectrum and it fails. Company X makes a product, wants to sell said product and understands advertising. Company X doesn’t knock on my door every day, therefore Company X doesn’t exist.

        • randomengineer September 7, 2020, 10:10

          The original effort by SETI was to search along the 1.4 GHz band with the argument that this band was the most obvious electromagnetic signaling frequency. Your logical fallacy claim therefore extends to the formation/purpose of SETI itself.

          What I have suggested is that ET going for the most obvious signal would also do it so that it requires the least energy expenditure. Think in terms of parsimony. The simplest signal and the simplest, most robust engineering to get the job done. Is there a reason the KISS principle shouldn’t be known to ET?

          Why blow the energy of a star on transmitting devices when the star itself is already a lighthouse? Sufficiently advanced ET might have tech that lets it bomb a star such that it oscillates for a few million years. There’s probably any number of ways to fiddle with a natural lighthouse to make it into a signal.

          In sum, an ET wanting to create an obvious signal is not going to find a Rube Goldberg way to do that.

          What you’re arguing here is different; you’re looking to posit reasons why ET may not want to signal.

          • Harold Shaw September 8, 2020, 11:01

            SETI can’t be using the black and white fallacy if they are looking for beacons that don’t qualify as the most visible beacons possible. Radio transmissions in the watering hole would be less obvious than some versions of the method you are offering.

            I am not arguing that ETI won’t signal, though that is a possibility. Instead, I am arguing that the cost to signal won’t dominate the method of signalling, the goal of signalling will. If the goal is long term diplomacy or trade, then extremely obvious beacons may not be optimal. An obvious beacon demonstrates that the sender is willing to force themselves into the culture of the receiver. A star that behaves unlike any other star to the naked eye could be the basis for a religion and all the negative implications that follow. Consent for engagement isn’t a priority for the transmitter. The demands placed on trading value by interstellar distances, time and the cost of bandwidth dictate that the most valuable resources will be resources that each civilization can’t produce themselves. Less mature civilizations will have fewer resources and be more vulnerable to cultural conversion. It may not be in the best interest of a mature civilization to engage with a significantly less mature civilization. The design of the beacon could eliminate or limit that happening.

            I think even an ancient civilization that has probes in the Solar system could use a beacon to start dialogue rather than just pop out of nowhere. The act of finding and pinging a beacon is clear evidence of consent to engage. Diplomacy can start from a strong footing when all parties are clearly willing. Trade that focuses on comparative value flourishes when the uniqueness of parties is protected.

            That being said, the beacon type you are advocating could be engineered to select for civilizations of a certain maturity level. Though it could be easy to confuse for a natural phenomenon.

  • ljk September 5, 2020, 21:00

    Want to Talk to Aliens? Try Changing the Technological Channel beyond Radio

    Finding cosmic civilizations might require a more innovative approach than listening for radio transmissions

    By Adam Mann on September 2, 2020


    The new study’s authors see their findings as one possible answer to the Fermi paradox, which asks why we have not found evidence of intelligent aliens, given that in the long history of our galaxy, some technological species could have arisen and sent dispatches of its existence across space by now. The work suggests this absence is not very meaningful—perhaps E.T. is too far away from us in space and time or is just using some calling card that is unknown to us.

    At the heart of the research is also an attempt to step away from some of the human-centric biases that tend to plague speculations about alien others. “It’s very difficult to imagine extraterrestrial communication without our anthropomorphic way of thinking,” Funes says. “We need to make an effort to exit from ourselves.”

    Kopparapu concurs with this assessment. “Unexpected discoveries come from unexpected sources,” he says. “In our common-knowledge thinking, we are in a box. It is hard for us to accept that there could be something else outside it.”

    • DCM September 6, 2020, 12:33

      Exactly. We don’t know what they might be like so we have to be cautious. And that includes the possibility we could harm them and not know it.

      • ljk September 8, 2020, 9:38

        Or they could harm us. However, we always worry that beings from beyond Earth could be the threat, while it is just as possible that we could become the alien invaders, although I believe it is our machine descendants who will do the exploring of the stars and not us, unless we have groups that take off in multigenerational vessels.

        • DCM September 9, 2020, 4:50

          Those are valid possibilities. The problem is overassuming and overdoing them in the mental climate of self-hatred that’s been cultivated since WWII. Bear them in mind but don’t act on them till they appear needed.
          We should listen and look but develop what’s within reach for our own purposes and be grateful there’s no life in our immediate reach to be concerned with.
          Generation ships are for the future though developed from off-world biospheres.

          • ljk September 10, 2020, 12:19

            It may be better to look at what you call “self hatred” about our species as a critical self-examination, which we need in a world where our technology and overpopulation are exceeding our biological level of wisdom and knowledge. Otherwise, we will surely become dogmatic and then irrelevant, if not extinct.

            Let Jacob Bronowski explain:


            • DCM September 11, 2020, 4:54

              It isn’t any kind of self-examination because it mistakes hatred of oneself for objectivity.
              It’s based on the culmination of World War II, itself a consequence of World War I. There were nearly 40 years of war between about 1910 and 1950, which was unusual only because of scale and improved communications.
              The Allies had no reason to blame themselves but did — yet despite decades of smaller conflict there was nothing following on the same scale. Blaming ourselves isn’t the same thing as not being domineering and tyrannical. Winning the war involved mass casualties but wasn’t the same thing as building factories to exterminate whole races.
              Time to drop knee-jerk self-criticism and return to a hopeful outlook.

  • ljk September 11, 2020, 10:30

    We can and need to be both hopeful/optimistic while also making sure we don’t become narrow-minded egomaniacs as a culture. Constant self-examination and monitoring are essential.

    I think the attitude towards space exploration, utilization, and settlement is finally starting to swing the other way after several decades of indeed negative thinking. The private sector is playing a large role in this regard.

    And look at this new article:


    “Space is part of the solution set, and when you deal with big problems, you want to have access to as many solution sets as possible,” says Rich Cooper, vice president for strategic communications and outreach at the Space Foundation, a nonprofit education and advocacy group.

    • DCM September 11, 2020, 12:21

      Self-examination is one thing, incessant self-criticism is another.
      Maybe some philosopher will develop an effective method that’s neither negative nor “egotistical”. There’s a project for today’s students.
      I might say that the self-hate I mention is part of the reason for the long period in which space travel and utilization slowed almost to nada.

    • Alex Tolley September 11, 2020, 14:04

      “Space is part of the solution set, and when you deal with big problems, you want to have access to as many solution sets as possible,” says Rich Cooper, vice president for strategic communications and outreach at the Space Foundation, a nonprofit education and advocacy group.

      This is “talking one’s own book”. He was hardly likely to say “Space is NOT part of the solution set”. ;)

      I don’t believe we suffer from “self haterd”, but I do think we need to examine some things more carefully. SpaceX fanbois are over the Moon about Starlink and getting cheaper high speed broadband (we’ll see) but clearly these satellites do impact ground observations of space, despite the claims that this is false. You have also decried the light pollution from our thoughtless use of lighting, even though many would argue the tradeoff might be worth it. Now that it is becoming clear that air pollution is shortening lives, just maybe the pendulum will start to swing back against unregulated industry emissions. As smoke colors the sky where I live in California, with the worst ever year for wildfires (and that is before the season is really under way) just maybe we can start to appreciate that our economy will suffer along with the environment if we do not change our behavior. To think we might just go the way of other civilizations due to being in denial of change and not adapting is just depressing for a supposedly intelligent culture.

  • DCM September 12, 2020, 4:45

    Air pollution is damaging. The solution is to continue developing more basic and efficient technologies, not to blame ourselves for previous lack of knowledge and commit cultural suicide.
    We aren’t causing large scale climate fluctuations. People have been around about 200,000 years and the climate has dramatically altered during that time. People adapted. I doubt a few thousand campfires and the clicking of flintwork caused any of these changes or that any culture on our scale existed without leaving abundant remains.
    Glacial accumulation dropping sea levels and recent melting that inundated continental shelves and submerged huge regions are the result of astronomical and geological factors beyond our reach.
    Throwing girls into volcanoes doesn’t change the weather…