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Into the Cosmic Haystack

A new paper from Jason Wright (Penn State) and colleagues Shubham Kanodia and Emily Lubar deals with SETI and the ‘parameter space’ within which we search, with interesting implications. For the researchers show that despite searching for decades through a variety of projects and surveys, SETI is in early days indeed. Those who would draw conclusions about its lack of success to this point fail to understand the true dimensions of the challenge.

But before getting into the meat of the paper, let’s talk about a few items in its introduction. For Wright and team contextualize SETI in relation to broader statements about our place in the cosmos. We can ask questions about what we see and what we don’t see, but we have to avoid being too facile in our interpretation of what some consider to be an ‘eerie silence’ (the reference is to a wonderful book by Paul Davies of the same name).

Image: Penn State’s Jason Wright. Credit: Jody Barshinger.

Back in the 1970s, Michael Hart argued that even with very slow interstellar travel, the Milky Way should have been well settled by now. If, that is, there were civilizations out there to settle it. Frank Tipler made the same point, deducing from the lack of evidence that SETI itself was pointless, because if other civilizations existed, they would have already shown up.

In their new paper, Wright and team take a different tack, looking at the same argument as applied to more terrestrial concerns. Travel widely (Google Earth will do) and you’ll notice that most of the places you select at random show no obvious signs of humans or, in a great many cases, our technology. Why is this? After all, it takes but a small amount of time to fly across the globe when compared to the age of the technology that makes this possible. Shouldn’t we, then, expect that by now, most parts of the Earth’s surface should bear signs of our presence?

It’s a canny argument in particular because we are the only example of a technological species we have, and the Hart-style argument fails for us. If we accept the fact that although there are huge swaths of Earth’s surface that show no evidence of us, the Earth is still home to a technological civilization, then perhaps the same can be said for the galaxy. Or, for that matter, the Solar System, so much of which we have yet to explore. Could there be, for example, a billion year old Bracewell probe awaiting activation among the Trans-Neptunian objects?

Maybe, then, there is no such thing as an ‘eerie silence,’ or at least not one whose existence has been shown to be plausible. The matter seems theoretical until you realize it impacts practical concerns like SETI funding. If we assume that extraterrestrial civilizations do not exist because they have not visited us, then SETI is a wasteful exercise, its money better spent elsewhere.

By the same token, some argue that because we have not yet had a SETI detection of an alien culture, we can rule out their existence, at least anywhere near us in the galaxy. What Wright wants to do is show that the conclusion is false, because given the size of the search space, SETI has barely begun. We need, then, to examine just how much of a search we have actually been able to mount. What interstellar beacons, for example, might we have missed because we lacked the resources to keep a constant eye on the same patch of sky?

The Wright paper is about the parameter space within which we hope to find so-called ‘technosignatures.’ Jill Tarter has described a ‘cosmic haystack’ existing in three spatial dimensions, one temporal dimension, two polarization dimensions, central frequency, sensitivity and modulation — a haystack, then, of nine dimensions. Wright’s team likes this approach:

This “needle in a haystack” metaphor is especially appropriate in a SETI context because it emphasizes the vastness of the space to be searched, and it nicely captures how we seek an obvious product of intelligence and technology amidst a much larger set of purely natural products. SETI optimists hope that there are many alien needles to be found, presumably reducing the time to find the first one. Note that in this metaphor the needles are the detectable signatures of alien technology, meaning that a single alien species might be represented by many needles.

Image: Coming to terms with the search space as SETI proceeds, in this case at Green Bank, WV. Credit: Walter Bibikow/JAI/Corbis /Green Bank Observatory.

The Wright paper shows how our search haystacks can be defined even as we calculate the fraction of them already examined for our hypothetical needles. A quantitative, eight-dimensional model is developed to make the calculation, with a number of differences between the model haystack and the one developed by Tarter, and factoring in recent SETI searches like Breakthrough Listen’s ongoing work. The assumption here, necessary for the calculation, is that SETI surveys have similar search strategies and sensitivities.

This assumption allows the calculation to proceed, and it is given support when we learn that its results align fairly well with the previous calculation Jill Tarter made in a 2010 paper. Thus Wright: “…our current search completeness is extremely low, akin to having searched something like a large hot tub or small swimming pool’s worth of water out of all of Earth’s oceans.”

And then Tarter, whose result for the size of our search is a bit smaller. Let me just quote her (from an NPR interview in 2012) on the point:

“We’ve hardly begun to search… The space that we’re looking through is nine-dimensional. If you build a mathematical model, the amount of searching that we’ve done in 50 years is equivalent to scooping one 8-ounce glass out of the Earth’s ocean, looking and seeing if you caught a fish. No, no fish in that glass? Well, I don’t think you’re going to conclude that there are no fish in the ocean. You just haven’t searched very well yet. That’s where we are.”

This being the case, the idea that a lack of success for SETI to date is a compelling reason to abandon the search is shown for what it is, a misreading of the enormity of the search space. SETI cannot be said to have failed. But this leads to a different challenge. Wright again:

We should be careful, however, not to let this result swing the pendulum of public perceptions of SETI too far the other way by suggesting that the SETI haystack is so large that we can never hope to find a needle. The whole haystack need only be searched if one needs to prove that there are zero needles—because technological life might spread through the Galaxy, or because technological species might arise independently in many places, we might expect there to be a great number of needles to be found.

The paper also points out that in its haystack model are included regions of interstellar space between stars for which there is no assumption of transmitters. Transmissions from nearby stars are but a subset of the haystack, and move up in the calculation of detection likelihood.

So we keep looking, wary of drawing conclusions too swiftly when we have searched such a small part of the available parameter space, and we look toward the kind of searches that can accelerate the process. These would include “…surveys with large bandwidth, wide fields of view, long exposures, repeat visits, and good sensitivity,” according to the paper. The ultimate survey? All sky, all the time, the kind of all-out stare that would flag repeating signals that today could only register as one-off phenomena, and who knows what other data of interest not just to SETI but to the entire community of deep-sky astronomers and astrophysicists.

The paper is Wright et al., “How Much SETI Has Been Done? Finding Needles in the n-Dimensional Cosmic Haystack,” accepted at The Astronomical Journal (preprint).


Comments on this entry are closed.

  • Karl Pestell October 2, 2018, 15:08

    I’ve just scanned this paper, but I’m stuck on “bright and obvious radio beacons.” We’re not doing this any more – we’ve gone dark, we’re all fibre optics and cellular networks. Bit of aircraft radar etc, but I don’t think we’re outshining the Sun in much. And what’s more, I think this trend is set to continue – 50 years from now, we may well be much darker still.

    So, can anybody tell me – with the 2018 technologies that we’re actually using right now to look – how far out we could detect a completely analogous 2018 civilisation? Some months ago, I did the calculations myself and worked out if our technology was around Proxima Centauri, we couldn’t detect the Earth’s radio signature. I’ve read we could detect stuff half way across the galaxy which I thought was preposterous, so I wanted to do the figures myself and see what came out. Unless I’ve got these figures completely wrong, it would seem the chances of radio SETI finding something other than intentional beacons is effectively zero.

    Has anybody else done this calculation?

    • Paul Gilster October 2, 2018, 17:22

      Karl, the Benfords have done calculations on how far out our current signals could be detected. It isn’t far. Check the archives here for discussions of this, and if you come up short, let me know and I’ll dig up some relevant materials. Anyway, the idea that ‘I Love Lucy’ is being watched 65 light years out has been pretty well discounted.

      • J. Jason Wentworth October 3, 2018, 1:43

        Another factor, which Ronald Bracewell mentioned, is the bending of radio signals by the galactic magnetic field, such that even a radio signal that was (hypothetically) beamed directly at us could miss us by a wide margin (this effect would be more pronounced with weaker and/or more distantly-originating signals). He also mentioned another possible factor, that–to my knowledge–no one (on Earth, at least) is looking for:

        Lower frequency radio waves (even LW [Long Wave] and Medium Wave [such as AM radio stations’ signals], and even VLF–Very Low Frequency–signals) can sometimes, under the right conditions, not only pass through our ionosphere and escape into space, but they can even be naturally *amplified* by their ionospheric passage. This phenomenon may make our low frequency (particularly LW and MW) broadcasts detectable–and maybe even decode-able–at interstellar distances, because some of these stations do (and have) broadcast at power levels of 0.5 – 1+ million watts (these include/included WLW 700 AM in Cincinnatti, the Mexican “border blaster” AM stations, and Long Wave radio stations around the world), and:

        To other civilizations with radio telescope antennas in space, even such low frequency signals would be detectable. The RAE (Radio Astronomy Explorer) 1 and 2 satellites (RAE 2 was put into orbit around the Moon to utilize it as an “Earth RF noise shield”) were launched to observe the heavens at lower radio frequencies, but to my knowledge, no SETI observations (or even data set searches) were made with/from these missions.

        • ljk October 3, 2018, 14:22

          I love throwing out this little bit of SETI history:

          The Soviet Mars probe called Mars 7, which attempted to place a lander on the Red Planet in 1974, but somehow missed the entire world, did conduct Optical SETI during its mission! Would love to have the details on that effort.

          Gamma ray bursts were also checked for signs of intelligent signals by the Soviet Venus probes Venera 11 and 12 and the American Pioneer Venus orbiter in 1978.


          • J. Jason Wentworth October 4, 2018, 1:30

            Those Soviet Mars missions were all pre-programmed, which revealed the weakness of that method. They did start a tradition of mission re-purposing, though, which continues–with even greater vigor than back then–to this day:

            Mars 2 and 3, two orbiter/lander spacecraft, arrived during the late 1971 planetary dust storm that delayed Mariner 9’s orbital survey–unlike the Vikings, though, their landers had to be separated before orbit insertion, and the Soviets hadn’t planned for a planet-wide dust storm! (If not for that storm, incidentally, Mariner 9 might not have examined Phobos and Deimos at all, because NASA–as Carl Sagan related in “The Cosmic Connection”–initially opposed investigating the moons, and only grudgingly permitted a satellites astronomy team to be formed at JPL; after a blank Mars greeted Mariner 9’s vidicon TV cameras, they suddenly became interested in looking at “the hurtling moons of Barsoom” :-) ). Meanwhile, the Soviets were having their own “dust storm blues”:

            Mars 2’s lander crashed, and Mars 3’s lander transmitted for only 20 seconds after beginning transmission following touchdown, returning just a portion of a featureless TV picture; the cause of the failure is unknown. Both landers carried small, cable-connected Prop-M rovers, but they never got a chance to operate. Neither of the two orbiters returned very many pictures or a great amount of data (much of which was during the time of the dust storm’s obscuration of the surface), and:

            Mars 4, 5, 6, and 7 (launched during the less favorable 1973 launch window, reaching Mars in the spring of 1974) comprised two orbiters (Mars 4 and 5) and two lander-carrying flyby spacecraft (Mars 6 and 7). Mars 4 failed to enter Martian orbit due to a computer failure; Mars 5 did little better, failing just a few days after braking into orbit, and the landers did even worse:

            Due to a chip that had degraded during the mission, contact with Mars 6’s lander was lost just before its retrorocket was to fire, only seconds prior to touchdown. The Mars 7 lander initially failed to separate from its flyby bus, but it eventually did; this did little good, however:

            Due to a retrorocket failure (perhaps on the bus, as the landers, to my knowledge, each had only one, quite small solid propellant “tractor” retrorocket that fired–and separated the parachute–as the ‘chute-supported lander neared the ground), the Mars 7 lander flew by Mars and–like its flyby carrier bus–remains in solar orbit. The SETI observations must have been conducted using the Mars 7 flyby bus (rather like how the EPOXI mission–a follow-on to the Deep Impact mission, using the impactor carrier bus spacecraft–conducted exoplanet observations), which was a nice way to salvage an otherwise-disappointing, and already-paid-for, Mars mission.

            • ljk October 4, 2018, 13:05

              Thank you for these details. I have read that the Mars 6 lander failed because it hit the Martian surface at a greater velocity than it was designed for. In other words, it crashed like Mars 2.

              However, unlike Mars 2, it did return the first in situ analysis of the Martian atmosphere during descent. Unfortunately, the Mars 6 data was interpreted as indicating that argon was a constituent of the planet’s atmosphere, which messed with later research until Viking came along.

              Perhaps someone will look for Mars 6 in MRO images just as they did with Mars 3 so we can determine if the lander actually survived intact or is in pieces.


              • J. Jason Wentworth October 4, 2018, 20:22

                Thank you for posting that MRO link! Mars 3 provides a “model” for what an intact Mars 6–if it is so–should look like from orbit. The Mars 6 failure details seem to have changed over the years (perhaps due to the Soviet policy of secrecy, “results interpretation to put the best public face on failures,” and selective release of details). The revelation that the bad chip made much of the data unusable and garbled appears to be recent, and:

                I had never before heard about the Mars 7 optical SETI effort, which I’d wager you’re right about (that it was only for the benefit of a few scientists [maybe even “piggybacked onto” post-flyby engineering tests to discover what caused the lander failure]). I know nothing more about the mission or its SETI observations (“Are there any Mars 2 – 7 knowledgeable ex-Soviets in the house?” :-) ).

            • ljk October 4, 2018, 13:08

              I wanted to add about Mars 7 and its OSETI observations: They may have offset the lander missing Mars, but it may have only been for a few scientists, as I did not know about the SETI effort until years later and in a rather obscure and detail-light source.

              Do you know of any papers or other information on what Mars 7 did with its SETI effort and its results? Who would have thought that a Soviet Mars probe from the 1970s was doing Optical SETI two decades before looking for light signals became acceptable to the mainstream SETI folks after initially rejecting it in 1961.

          • J. Jason Wentworth October 4, 2018, 2:07

            Also in that connection (using the Mars, Venera, and Pioneer Venus Orbiter spacecraft’s instruments for making SETI searches at various wavelengths), we *really* do–for planetary defense (including from coronal mass ejections, not just asteroids and comets) as well as scientific (including SETI) reasons–need to establish a new network of solar-orbiting Pioneer 6 – E type interplanetary probes (see: http://en.wikipedia.org/wiki/Pioneer_6,_7,_8,_and_9 ); they could do the following for us:

            Pioneer 6, 7, 8, and 9 orbited the Sun–two between Earth and Venus, and two between Earth and Mars–and a fifth probe in the series (Pioneer E, which would have been Pioneer 10 had its Delta rocket not failed–here’s the Pioneer E press kit: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19690026632.pdf ) was to have orbited in an “in-and-out,” Earth-crossing orbit that would have kept it within 10 million miles of the Earth during its planned 1/2 to 2-1/2 year mission (Pioneer 6, 7, 8, and 9 lasted ^decades^ longer; in fact, only Pioneer 9 is *known* to have died, in 1983–no one listens to the others anymore, since 2000 or so :-( ). The four operational Pioneers served as the first solar warning network (including for the Apollo lunar missions; they enabled three-dimensional analysis of the solar wind), and on March 20, 1986, Pioneer 7 flew within 12.3 million kilometers of Halley’s Comet, monitoring the interaction between the cometary hydrogen tail and the solar wind. It discovered He+ plasma produced by charge exchange of solar wind, and He++ with neutral cometary material. Now:

            A new series of Sun-orbiting Pioneer probes could also provide such “triangulative” solar monitoring (including in more-inclined solar orbits), and they could also conduct “flybys of opportunity” of Amor/Apollo/Aten asteroids and short-period comets (and with a little luck, a few long-period comets, too–and maybe even interstellar interlopers). In addition to their normal fields & particles instruments, they could each carry a “push broom” spin-scan camera (like Juno’s JunoCam), as well as gamma ray, UV, and radio instruments for–among other things–SETI investigations.

        • AlexT October 4, 2018, 2:47

          LW, VLW, SW – is very obvious choice, most probable that other civilisation will use those frequencies for theil local communication and broadcast exactly like we use it, because it much easier to implement on the first steps of RF communication technilogy development.
          But on other sude the SETI antennas for VLW/LW/SW will have significantly bigger dimentions and have to be installed out of Earth’s athmosphere (in space)…

          • J. Jason Wentworth October 4, 2018, 20:40

            Yup–fortunately, there is plenty of room in space (and on the Moon and asteroids) for setting up dishes, dipole arrays or loops (even with reflectors), and other VLF through SW radio astronomy *and* SETI antennas. Many of them could be deployable and spin-rigidized (the low-frequency natural radio emissions of stars, nebulae, and other objects would also be scientifically useful), and:

            I agree with you about the (literally) universal utility of radio, including at those frequencies, to technological civilizations everywhere, including because it can be done using very little transmitter output power. Even our Moon has been found to have a slight but usable ionosphere, which would enable global lunar communications at low data rates, at frequencies of around 1 MHz (which is about in the middle of the 530 kHz – 1700 kHz AM broadcast band [narrowband FM and digital modes, including “packet radio,” could also be used at such frequencies for lunar communications]).

    • Jason Wright October 2, 2018, 18:43

      The full SKA project will be sensitive to today’s radio leakage from ordinary omnipresent radio leakage at a few parsecs:

      We are certainly outshining the Sun and the rest of the Solar System by a lot at the higher frequencies.

      We might be going “quiet” for ground-based communication purposes, but there is still our omnipresent radar, and any spacefaring species needs to use photons to communicate throughout its stellar system.

      • neutrino78x October 3, 2018, 8:31

        A few parsecs isn’t far though. You’re talking about around 20 light-years. Trappist-1 is, what, 50 light-years away? So basically they couldn’t hear us. :(

        SETI has to get a lot more sensitive before we can draw conclusions. :)

      • Jake October 3, 2018, 14:00

        ” outshining the Sun and the rest of the Solar System by a lot at the higher frequencies”

        I did a little digging and couldn’t find much in the way of numbers on this. (And by ‘higher frequencies’ I assume you mean from a radio point of view? Like, say, VHF/UHF/SHF? )

        It is the case tho that not necessarily a lot of power is needed for space-based things, New Horizon’s output is just a handful of watts.

      • Michael C. Fidler October 5, 2018, 9:41

        You are correct on that, Military and FAA radars have reached beyond 60 light years but it would be anywhere from 0 to another 60 years before we would hear from them. Yes, we are still blaring away at this moment, so if you are worried about aliens finding us, they have the perfect beams to zero in on us…
        Take it from an expert – I was 4 years in the Air Force working NORAD radars and 25 years in the FAA as an Air Traffic controller.

    • AlexT October 3, 2018, 6:20

      “I think this trend is set to continue – 50 years from now, we may well be much darker still”
      Agree, it seams that our civilization passed RF emission burst to Universe, we are going to be more quiet.
      We are going to use electromagnetic waves more efficiently i.e. use less power for the same (as in past) distance communication with higher information transfer throughput . Signal modulation is going to use wider passband , less used for analog signal transmission, more for digital and digital transmission became similar to natural noise source, i.e. when signal weak – it is hardly distinguished from natural noise.
      I do not know how modern SETI activists are going to detect noise like digital signals from ETI, but it is many orders complicated task than coherent carrier detection (CW).

      • J. Jason Wentworth October 4, 2018, 20:47

        You’ve just inspired a thought–how about this for a beacon idea? Io, orbiting Jupiter, triggers very powerful radio emissions from the planet’s magnetic field when it crosses the plasma flux tube; if a more advanced civilization altered the orbits of a local Jovian planet’s moons so that they “blasted out” regularly-varying radio pulses–and maybe even prime-number pulses, at intervals (depending on the moons’ inter-weaving orbits)–that would be a free (once it was arranged), perpetual, omni-directional radio beacon.

        • AlexT October 6, 2018, 10:28

          My “problem” that I beleive that none civilization that have high intellectual level will build (use) beacon for SETI entusiasts on the Earth – on my opinion it is nonsense.
          So we can onky hope to catch some RF (optical) signature, RF feats better this purposes, but we have some chance to catch this signals only in condition that it is radiated by omnidirectional (or close to it) anntenna, I beleive we have almost no chance to tune our receiver into narrow electromagnetic beam and exactly same moment when we and ETI switch on transmission/reception , so probability to catch narrow beam in unknown moment from unknown direction – is close to zero (even if it will be signal from ETI analog of our Breakthrough Starshot ) …

    • ljk October 3, 2018, 10:21

      SETI has often assumed that aliens will have beacons set up in deep space, beaming attention signals across the galaxy over and over for ages.

      Why? Out of the goodness of their hearts? This is seldom given a detailed reply, expect perhaps that the advanced species are therefore kind and want to help less sophisticated societies advance too.

      In 2000 I talked to an astronomer who said an advanced ETI might be beaming us messages from distant galaxies. When I asked him why, especially since it would take millions of years for their signals to reach us and just as long if anyone was going to reply, he simply said because they could.

      I hope the SETI community will finally start to examine the sociological and psychological reasons and methods of species for wanting to do things like let the rest of the Universe know they exist, rather than just assuming ETI will beam messages into space “just because they can.” The time of pure academic exercise is over.


      • Alex Tolley October 3, 2018, 11:50

        My name is Ozymandias, King of Kings;
        Look on my Works, ye Mighty, and despair!

        While it is human to create monuments and write books for the centuries, there is no a priori to assume that ETI will not do something similar, especially if civs are separated in time as well as space. Bracewell thought there might be such chain communications in his book on Intelligent Civilizations.
        That is just for star bound civs that he assumed. If civs are interstellar travelers, then they might also go through phases of birth, decay and rebirth. Maintaining a fount of knowledge to help bootstrap such far colony civs might make a lot of sense. This is just the interstellar distributed version of Heath Rezabek’s “Vessels” concept that has been posted on this site in the past.

      • hiro October 3, 2018, 16:30

        They could but they would not do just like the way because we can give some ant colony “lots of food” but it doesn’t mean we want to do it. Yeah, there is no galactic free lunch after all. On the other hand, some kids do give out lots and lots of water or gasoline to some random ant colony.

      • J. Jason Wentworth October 4, 2018, 2:35

        The cost, difficulty, and time-investment that “beaconeering” require are what made Ronald Bracewell favor interstellar messenger probes (even fly-through ones, after he’d considered the cost/benefit ratio of slower, immortal, star-orbiting sentinel probes; sending a second fly-through probe to a second target star would be far cheaper than having a sentinel probe wait for technological intelligence to arise in its assigned star system, which might take forever), and:

        Since the messenger probes would also be “straight” star- and planet-investigating probes (which could also return data on the interstellar medium while in transit to their target stars), they would be a “no-lose” proposition. No matter what they found, it would be scientifically interesting, even in systems without life (or without technological intelligent life). Plus, slowing or interruption of the probe launching program due to contingencies on the home planet wouldn’t affect the success rates of probes that were already on their way to their targets (the program would be tolerant of reallocation of resources to urgent priorities), and they could “check-in” at staggered, programmed times (to avoid interfering with each other’s signals), so maintaining the tracking and reception infrastructure would be cheap.

    • ljk October 4, 2018, 12:56

      I posted this link further down in the comments thread a few days ago, but in case you did not see it:


      • J. Jason Wentworth October 4, 2018, 20:50

        Indeed I did–and I also saved it, as a most informative reference–Thank You!

  • Jake October 2, 2018, 15:20

    Most parts of the Earth’s surface do in fact bear signs of our presence, it’s just a matter of looking for them. (c.f. Roman lead production in Greenland ice cores)

    • Alex Tolley October 2, 2018, 18:15

      The droughts across Europe have revealed a number of hitherto invisible sites. Just recently, the possible birthplace of Henry VII was found inside the walls of Pembroke castle. Elsewhere, declining lake levels due to over-extraction of freshwater have revealed ancient settlements, much like those discoveries in the seas by divers.

      A previous post on CD has raised the issue of what might be detectable in the Anthropocene if humans disappear.

      All of these ideas will require boots or probes on the ground for exoplanets, although some large structures or ruins might just be visible with extremely large telescopes.

      If only ET would orbit transiting structures that would create a prime number series with transit data – they really should be more considerate of us primitives. Maybe they could move a bright celestial object to shine down on a small village in the Middle East… ;)

  • Alex Tolley October 2, 2018, 15:33

    This seems to be the money quote:

    Much of the SETI literature is dedicated to guessing or reasoning which haystacks might contain many needles.

    One might go further and suggest that the haystack is really the available technology space, and the strategy to find needles based on available technology and funding available to the researcher.

    In a pre-high-tech age, recording lights in the sky, or supernatural manifestations would be the strategy, even if the interpretation wasn’t ETI.
    In the 19th century, optical telescope age, looking for canals on Mars was a local approach. With the invention of the radio telescope, we started looking for beacons, or possibly leakage from the “galactic club”. That is still the dominant strategy, although optical SETI gained traction. With the invention of lasers, we now have searched for laser communication or power beaming such as Lubin’s M-31 search previously posted.
    As we ponder the deep time of the galaxy, we realize that civs may have come and gone, so looking for archaeological evidence is another approach. Because Dyson posited the logic of fully tapping a star’s energy, we look for evidence of Dyson spheres or swarms. With the evidence that life appears to have appeared on Earth at a very early period, there is the approach for looking at clues in our biology for non-local and natural genesis, Thomas Gold’s panspermia theory is relevant here – we are just detritus from visiting biological astronauts.
    We could come full circle, as Clarke’s “Starchild” (and other non-physical manifestations of ETI) may be influencing us directly. Just about any posited supernatural phenomenon you can shake a stick at might be interpreted at a non-physical ETI.

    IOW, the “search space” is dependent on our cultural and technological capabilities., and direct projections of those capabilities. As we should know, ETI, if it exists, is highly unlikely to be anywhere close to our current technological status. Either it is primitive and pre-high-tech, or so far ahead technologically that our capabilities are no better that beaver dams in comparison. [Images of smart beavers looking for obviously artificial lakes comes to mind ;) ]

    If any ETI culture wants to uplift nascent technological cultures, beacons should be obvious and use the most primitive approach to at least draw attention to possible more complex information transfer. If they don’t, then the archaeological approach seems most likely to be successful, just as finding other dead civs on Earth has been.

    If centuries go by and SETI comes up empty, as well as our early interstellar probes, I hope that SETI doesn’t become a religious or quasi-religious endeavor, looking to build the equivalent of every more elaborate venues for focusing rites (e,g sacrifices) and communication (prayer) to discover that elusive ETI (deity).

    • AlexT October 4, 2018, 3:10

      “I hope that SETI doesn’t become a religious…”
      I am afraid – that for some people SETI already became the religion, when I met here in coments on this site phrases like: “just open your mind…” This resemble to me some hinduist or Buddhist religious practice.
      I temember that there were Hippies that claimed to use LSD to “open your mind”… hope it will not be never applicable to SETI…

      • ljk October 4, 2018, 12:54

        Some people will always treat and turn everything into a religion. It is our primitive nature instinctively reacting to the unknown. Their behavior is neither the defining nor guiding trait of SETI. It is a science – it just happens to be one trying to answer a very big question (perhaps the most important one of all) on a fairly meager diet of money and resources while simultaneously combating generations of ignorance and ridicule.

  • ole burde October 2, 2018, 16:05

    To keep an open mind has never been easy , and never will . One the one hand it would be stupid to cancel funding to Seti projects in such an early state of our search ….but one the other hand it is equaly stupid to deny the possiblity that we might be completely alone in this galaxy …….the human mind inevitably will try to reestablish a NEW closed beliefsystem out of the ashes of the older ones….such as the solid belief in the existence of advanced alien cultures

    • ljk October 3, 2018, 10:13

      The SETI community has known and admitted since its early days that our current capabilities will only work best if an alien civilization is deliberately beaming very strong signals right at Earth. We might get lucky and pick up their leakage, but we will really need them to almost literally hit us over our collective heads to get humanity’s attention on a cosmic scale.

      That is why the SETI community finally starting to take seriously the idea of looking for their astroengineering projects, because let’s face it, we are only going to notice the really advanced societies who are working at interstellar levels.

      This article describes numerous potential communications methods, including information on how far various signaling methods might reach into the galaxy:


  • Andrei October 2, 2018, 17:34

    Though I think intelligent life is very rare.
    And the chance that a technological life that use a lot of energy to and actively to seek out others is active right now at the same time as us – as small as having the winning ticket in the lottery.
    Even I think it’s worth looking.
    Because science is not about winning a lottery, even a negative result is a “winning ticket” not the grand prize but we then learned something about how rare intelligence is..

    • Alex Tolley October 2, 2018, 21:30

      Except that absence of evidence is not evidence of absence.

    • ericSECT October 3, 2018, 7:40

      Yes! Nailed it Andrei.

      Because a negative result is JUST as important as a positive result. Imagine the implications of that!

      • ljk October 3, 2018, 14:34

        Sadly this is why the Viking missions to Mars in 1976 were considered unsuccessful because they did not detect life on the Martian surface, or at least not in the way scientists presumed it would exist on that alien world over forty years ago. This also made NASA gunshy about conducting direct exolife searches for decades afterwards.

        • AlexT October 4, 2018, 3:15

          “This also made NASA gunshy about conducting direct exolife searches for decades afterwards.”
          I suppose the primary problem is – money , it is always limited.

          • ljk October 4, 2018, 12:49

            NASA could have afforded to add more biology detection equipment if they wanted to. Instead they balked after Viking. Note how the MERs were designed only to look for water signs on Mars and nothing else. Even some images that showed what looked like fossils were almost immediately rejected by the project scientists and others.

            Even the Curiosity Mars rover was “downgraded” from being an outright life searcher to one that looked for organic chemistry. Mars 2020 may finally be an actual life searcher, but we will see how the NASA publicity releases evolve.

            How gunshy is NASA about life on the Red Planet (and elsewhere)? Remember Mars Phoenix from 2008? When liquid water droplets were plainly seen on the metal legs of the robot lander, it took a fair deal of time for the space agency to officially declare that they were indeed water droplets, even though a child could have said as much.

            Maybe now, just maybe, all this is finally starting to change. I mean, NASA just sponsored a SETI conference, 25 years after cancelling its own SETI effort and making that acronym verboten to those both inside and out of the agency.

            • J. Jason Wentworth October 4, 2018, 21:07

              While all exobiological (and potentially exobiological) evidence must be evaluated carefully, I fear that a “negative religious” (not anti-religious) attitude has taken root in the minds of many scientists. The “negative religion,” which could result in us missing real evidence of past or present life (and might already have done so, at least with respect to Mars) is the attitude that:

              “We could *never* be that lucky” (to find present or fossilized life on Mars). In SETI, it’s the sad statement, “It’s *never* aliens.” This attitude has arisen because there have been so many possibly-promising results that ultimately turned out to be negatives, or false positives, but such a dejected attitude could cause real positives to me missed (scientists are only human, after all).

  • John October 2, 2018, 21:15

    Scoop a glass of water out of the ocean, put a droplet under a microscope, subject it to chemical analysis, and I guaruntee you’ll find evidence of fish, and a lot of other marine life. Perhaps we just aren’t looking hard enough at the space we have sampled, or are unaware of what to look for.

    • ljk October 3, 2018, 14:35

      Earth’s oceans are saturated with life. We have no idea this is the case with the galaxy, nor is it likely to be as easy to find with an equivalent scoop. We need to go out there and search directly.

      • J. Jason Wentworth October 4, 2018, 21:18

        *Nods* The fact that microbial life can’t be easily made in the laboratory (and has ^never^ even been closely approached, despite confident predictions in the 1960s that it would be routine within a decade) suggests that it may have been an exceedingly rare–and perhaps unique, here on this Earth–occurrence. There are certainly many, many, far simpler molecules (and mixtures of them) that satisfy the valence requirements (achieving the lowest, most stable energy states) of the elements in living organisms without coming anywhere near being self-replicating, much less approaching the complexity of RNA and DNA. “Life is a chemical luxury” that the universe could do just fine without (as it did once, and will again).

  • Michael C. Fidler October 2, 2018, 23:34

    It seems strange that human culture has put so much emphasis on supreme beings. In almost all the different civilizations that have developed over human history there has been alien or super humans embedded in their psyche. In all other animal life there is no similar concept, so are we a a demented species with an over active grey matter or is there a reason this occurs? So if we are the only ones is the idea of other civilizations any different then the cultures that built stone hedge or the pyramids?
    What if the scientific method and advanced math are just an aberration of our species and if other civilizations exist their path has been completely different from ours. After all the idea of the square does not have any relationship with nature or where we developed from on the earth. So is this just an recent development or has it been around for some 15 billion years? The only natural objects that may come close are crystals and humans have a long love for them and gemstones, so could this be because of some outside influence. Very strange…
    Just doing some comparative thinking to the rest of the intelligent species on this planet. Oh, Sorry, I forgot we are the only intelligent species on this planet – the Crown of Creation. ;-}

    • DCM October 3, 2018, 11:59

      If you appear to be bragging, even if it’s the truth, then you lose credibility and respect with any problem. Thus early accomplishments are credited to supernatural sources. I’ve read that the earliest Egyptian writing has the appearance of an individual invention (like Cherokee writing), though it was attributed to the god Thoth for some reason.
      Living in a family context, however, or even within a chiefdom or early kingdom suggests some powerful beings in charge, a naturally followed paradigm. If you piss off the king you’re toast; if something goes wrong the invisible gods are pissed off. So you have to sacrifice to them to keep them happy.
      Notice, however, that while Western people are happy to attribute early non-Western accomplishments to aliens nobody says aliens taught Benjamin Franklin that lightening is electricity and how to prove it or carved Mt. Rushmore. (Chinese people also seem exempt from alien influence). Signs we’re outgrowing superstition….

      • ljk October 3, 2018, 14:38

        Note how even to this day, if the “gods” let something terrible happen or do not seem to respond as expected, many people still assume there had to be some reason for it that we mere mortals could not fathom, rather than check into the possibility that perhaps there is no one behind the cosmic curtain operating things.
        Rather, it is more comforting to have a jealous and belligerent deity dictating all life than nothing at all.

        • Michael C. Fidler October 3, 2018, 19:56

          I know exactly where you two are coming from and I use to look at it that way, but maybe we need to look at are human attributes. Any ET visiting or just looking at us from afar is going to look at the whole population of humans plus any other intelligent creatures on the planet. Just as we would due if we found or will find the same situation someplace else, it may be why we are blind to ET contact! Believe me the Chinese have many alien and supreme beings in the their culture, but communism tried to destroy them. I’m just saying that our techno culture is just imprinting on the sky what we are. ET is sure to be long past that.

          • ljk October 4, 2018, 9:26

            We assume many things about advanced alien intelligences, including that if they have an interstellar level civilization then they are therefore peaceful and altruistic. As we see with humanity every day, being technologically sophisticated does not equal kindness and peacefulness. Sometimes it just makes one more effective at death and destruction.

    • J. Jason Wentworth October 4, 2018, 3:19

      Paul Davies, in “The Eerie Silence,” makes a good case that the development of science wasn’t inevitable even in human civilizations (only one did develop it), and this has sobering ramifications for any extraterrestrial races (to give just one example, intelligent but solitary-living beings could easily never come up with it, or even if one such being did conceive of science, the idea could easily just die with him/her/it). Also:

      Unless you have communicated with animals who told you, the idea that one or more supreme beings is a notion unique to human beings is an assumption. (It isn’t strange at all where human beings are concerned, though, because shamanic practices, which all human cultures developed, going back at least 30,000 years [that we know of; they are likely much older]–result in direct contact with such entities, as I know from experience with shamanic drumming.) But regarding the (other) animals:

      There is evidence (not conclusive proof, because the animals in question didn’t tell researchers about it; they were observed doing it) that at least some chimpanzees may have a notion of a “chimpanzee god,” a “big, powerful chimp in the sky.” I can’t recall where I read it (Jane Goodall may have made the observation), but chimpanzees in the wild were observed to defiantly react to thunderstorms, screaming and gesticulating at the sky just as they would to a revival chimpanzee, as if they were challenging some alpha chimpanzee up in the sky.

      • ljk October 4, 2018, 12:41

        I am not sure how being angry at a thunderstorm automatically turns into a chimpanzee god – maybe a lawgiver, but… (Planet of the Apes joke).

        My dog used to be terrified of thunderstorms and other such loud noises, but I doubt she was attributing them to an angry deity, although I admit I never asked her.

        I do distinctly recall a National Geographic article from a few years ago where chimpanzees were observed reacting excitedly (not angrily) to encounters with waterfalls. The article author, commenting on researcher observations, implied this behavior could be the germ of where humans began worshipping certain aspects of nature that excited and frightened them.

        Maybe this is where your idea came from? I would like to see more on this if possible.

        • J. Jason Wentworth October 4, 2018, 21:39

          I may have read it (about the wild chimpanzees challenging storms as they would rival chimps) in a National Geographic article as well; all I can remember is that I read it somewhere within the last five years. Waterfalls (which are often loud and awe-inspiring, particularly the big ones like Victoria Falls and Niagara Falls) could instill the same feelings in chimpanzees as thunderstorms. But there is much more involved in animism than just that, where human beings are concerned, although awe and fear at the ^physical^ powers observed and experienced–sometimes fatally!–in nature (storms, volcanoes, Earthquakes, etc.) make it hard to ignore the deeper aspects of what is going on, especially after one has personally experienced those (and they are relevant to interstellar exploration, as they also involve panpsychism, which scientists are beginning to investigate).

      • AlexT October 5, 2018, 2:40

        I am sure that “God” concept – it is ability of human brain to build abstract models of environment, present time we do not have any instrument that allows us to measure this ability of any animal’s brain, present moment only human being can tell us about his/her minds… and we know it is very individual thing.

        • Michael C. Fidler October 6, 2018, 3:23

          Well how many temples, churches, pyramids, or other structures have been built to supreme beings by any other species? Man has spent a lot of time and human suffering in the name of Gods and it seems funny that when and if the aliens arrive, would it probably be look upon as the arrival of the Gods, No? That is one thing we have not really considered when this happens. It seems man and his Gods and the benevolent Alien sound very similar – do you think we are going to meet someone like Spock or much more likely what Arrival portrayed? The evil, destroying aliens sell a lot of tickets, but if that was the norm in the galaxy expansion we would be long gone. What we should worry about is the techno geek in the control room or the fighter pilot with his hyper-sonic missile, come in contact with a real living supreme God!

          • AlexT October 6, 2018, 10:52

            “The evil, destroying aliens sell a lot of tickets, but if that was the norm in the galaxy expansion we would be long gone…”
            “We would be long gone” from evil alians – only when some basic conditions are exist simultaneously :
            1. There is some aliens in our Univers in additon to our civilization. Meanwhile we found none.
            2. The interstellar space travel is possible.
            3. Evil aliens are have more developped science and technology
            4. Evil aliens had found where we are.
            5. Evil alience have some interest to us.
            Etc. etc. etc.
            In same time we have one 100% fact – life on the Earth, it is very evil thing , where predators eat his pray, the Earth – it is the place , where more strong and adopted species survive.
            I cannot imagine why someone can suppose that wild nature and evolution laws can be different in other stellar location. Meanwhile we know that physics laws are same in every place in our Univers, evolution law it is direct consequence of physical laws.

            • Michael Fidler October 7, 2018, 18:38

              The intelligent herbivore would destroy the meat eating predators. Evolution may not be that stupid when it comes to intelligent’s. You may be right, so our cosmic doom is just waiting to filter us out of the game. Just remember to eat your fruits and veggies.

              • AlexT October 8, 2018, 3:46

                “The intelligent herbivore would destroy the meat eating predators…”
                Sorry, but I prefer to escape this religious discussion, your phrase above – it is religious postulate, it do not have any relation to realty, science or facts or evolution. human being is original creation that can invent amg try to implement ideas that contradict any logic, physical / biological / nature laws or facts.
                The road to hell is paved with good intentions

              • ljk October 8, 2018, 8:57

                Carl Sagan had the view in Contact (novel version) that “bad” species will destroy themselves long before they achieve interstellar flight. He also thought that advanced ETI would be beaming their equivalent of the Encyclopedia Galactica across the Milky Way to enlighten the less sophisticated.

                We shall see on both counts.

  • Harold Daughety October 3, 2018, 0:41

    It seems reasonable to assume that life has evolved on other worlds because it happened on this world. Interstellar travel is a completely separate matter and there is no valid reason to believe it is possible. Whether or not we can communicate with another intelligence is an open question.

    • J. Jason Wentworth October 4, 2018, 3:57

      Interstellar travel is not only possible, it began in 1972, with the launch of Pioneer F, which became Pioneer 10 following its successful launch (it was followed by Pioneer G [Pioneer 11], Voyager 1 & 2, and–almost 30 years after the Voyagers–by New Horizons), and:

      There is nothing sacrosanct about interstellar (or even intergalactic) spaceflight; it’s simply a matter of achieving a sufficiently high velocity to exceed the local solar (or galactic) escape velocity, which in the former case, Jupiter easily does for us. The important question is: “Is sufficiently fast interstellar travel possible?” Our individual lifespans, and the lifetime of our civilization, have a direct bearing on the definition of “sufficiently fast.” For example:

      To human beings, the minimum tolerable interstellar transit velocity–especially for probes, but also for “hibernation starships,” should they become feasible (Carl Sagan and I. S. Shklovsky concluded in 1966 that they most likely will be, utilizing high-pressure freezing techniques to prevent ice crystal damage to tissues)–is 1% of c, the speed of light, with higher velocities (10% of c and up) being preferable. But to much longer-lived beings, the interstellar distances would be–psychologically speaking–much smaller than they feel to us, such that 1% of c might be plenty fast (and much easier and cheaper to reach, too) to them. As well:

      We already have a working “engine” to power spacecraft to the stars–our own local star, the Sun. By utilizing a “beamer” mirror (a spin-rigidized, metallized plastic film, spherical section Sun-orbiting mirror just 500 meters across, sail probes carrying payloads of a few kilograms could reach the nearer stars in a few decades, as Greg Matloff pointed out in a paper about this concept). Even far larger crewed starships–either worldships, or hibernation ships–could reach our neighboring stars in a few centuries, using solar sail propulsion (and photonic *and* stellar wind braking at their destinations, by giving their sails a positive electric charge by ejecting electrons using one or more electron guns).

      • Alex Tolley October 4, 2018, 10:49

        “To human beings, the minimum tolerable interstellar transit velocity–especially for probes, but also for “hibernation starships,” should they become feasible (Carl Sagan and I. S. Shklovsky concluded in 1966 that they most likely will be, utilizing high-pressure freezing techniques to prevent ice crystal damage to tissues)–is 1% of c,”

        I don’t have the source to understand their reasoning, but it seems to me that the constraints are usually what the Earth civilization will accept, for reasons of ROI, etc. However, we have so many potential options for interstellar travel, that from the POV of the traveler, traavel duration isn’t relevant. A worldship establishing a human colony on a distant start won’t care if there is any civilization on Earth still extant. For other techniques where the sentient being is constructed/grown/revived on reaching the target, the duration is similarly irrelevant.

        If the aim is to seed the stars with human/Earth life, it might be best served by just spreading ships like dandelion seeds, and like non-sentient dandelions, not concerning itself with the outcome of each seed.

        We seem to be on the cosmic brink of sending out such small, cheap, interstellar “ships”. I can imagine that such vessels, carrying dormant microorganisms from bacteria to tardigrades might seed sterile worlds with life, restarting evolution on these worlds. While humanity may not last even a fraction of the time before those worlds bloom, artificial sentient machines might just do so, eventually making the journey to the worlds where the seeds took.

        If we can look past our parochial, anthropocentric views, it seems to me that interstellar travel is quite possible if done in certain, non-Trekkian ways.

        • J. Jason Wentworth October 4, 2018, 21:52

          Yes–I didn’t mention those other methods (and considerations, including for “we’ll get there whenever” worldship residents) only because they are so well-known. Humanity (as a group; many individuals are “already there” intellectually and emotionally) does need to be more patient regarding interstellar spaceflight. If the costs–especially for probes and “seed-conveying” missions–can be brought way down (and this looks promising, for Sun-diver [with occulter] and/or “solar beamer mirror” solar sail missions), we could start preliminary work on such missions now.

      • Ron S. October 4, 2018, 11:11

        “to much longer-lived beings, the interstellar distances would be–psychologically speaking–much smaller than they feel to us”

        Why wouldn’t they grow bored and otherwise disinterested? Many moons ago when I was in university my number theory professor gave us a pretty good working definition of problem intractability: when the solution time is greater than our attention span.

        • J. Jason Wentworth October 4, 2018, 22:11

          That is a legitimate and relevant question. Even among human beings, though, boredom isn’t a universal outcome when long-term projects are worked on (Goddard knew that he would never see space flight, but that didn’t make him bored with developing the supporting rocket technology for most of his life, and even as a boy he looked forward to it [and Tsiolkovsky couldn’t even develop rocket hardware]). I’ve never been bored (I sometimes got impatient for upcoming anticipated happenings when I was younger, but that isn’t the same thing), and even whole societies whose members live simply on purpose (monasteries, nunneries, the Amish, Mennonites, and Hutterites, etc.) don’t appear to suffer from boredom, and:

          While we don’t know if there are very long-lived intelligent aliens, much less know about their psychology if there are any such beings, it’s possible that with very long life could also come a different perception of the passage of time, such that boredom wouldn’t be a problem for them.

  • J. Jason Wentworth October 3, 2018, 1:07

    In the spirit of the arms-control advice, “Trust, but verify,” the appropriate mindset with which to approach radio and laser SETI, SETA, and Bracewell probes (including our own, in the future) is, “Doubt, but listen, look, and probe.” Also:

    Even at the very beginning of the SETI enterprise (which was called CETI–Communication with Extra-Terrestrial Intelligence–back then), Arthur C. Clarke, among others, including Cocconi and Morrison, pointed out that the odds of success were very small, but that the ramifications of success were so important that the search was worth making. They also said that if we *never* searched, the chances of success (absent an alien starship or probe entering orbit around the Earth, which we couldn’t help noticing) would be zero, and that even negative results–after decades or centuries of searching–would equally profoundly calibrate humanity’s place in the scheme of things, but:

    Fortunately, the cost of searching–in terms of equipment and software (like SETI@home), even “piggybacked” from astronomical observations–seems to be falling. In addition, very small interstellar sail probes, particularly reasonably fast “Sun-diver” ^solar^ sail ones, may be mass-produce-able within the foreseeable future, making it possible to observe exoplanets close-up (and even listen for “local” artificially-produced signals). This could enable us to detect “leakage” radio–and even optical–radiation (such as from mercury vapor or sodium vapor city street lights) as weak as most of our leakage radiation (except for our powerful military and planetary radars, which would “sound” to aliens rather like the brief “WOW!” signal [and similar ones] that we have detected from time to time).

  • Al Jackson October 3, 2018, 1:09

    I have always had a problem with an assumption implicit in the Hart-Tippler argument. That is that in the statistics the numbers are so big there should be at least one civilization like us, maybe many. That’s ok, but I fail to see how one can predict just what WE will do when we become star faring. Even if it is only instrumented probes to the stars, even Von Neumann machines. Predicting our civilization is a very nonlinear thing. Lyapunov exponents are trumping standard deviations.  

    • ljk October 3, 2018, 12:33

      Tipler’s ideas went off into the Twilight Zone a long while ago anyway. Religion cloaked as science.

  • Antonio October 3, 2018, 2:33

    “The ultimate survey? All sky, all the time, the kind of all-out stare that would flag repeating signals that today could only register as one-off phenomena…”

    Nope. The ultimate survey is METI. We aren’t searching for needles, we are searching for sentient beings. If you want to find a fish, put something in the hook.

    • Harold Shaw October 3, 2018, 10:27

      METI is not the ultimate SETI tool, just a valuable strategy that deserves the same respect and rigor as SETI. We can not guarantee that an ETI would respond to a message. That assumption reveals how dangerous anthropomorphism and narcissism is when designing hypotheses and experiments.

      • ljk October 3, 2018, 13:47

        However, SETI assumes that aliens will conduct their own METI to get the attention of us and others in the galaxy, namely those galactic beacons operating for ages.

        • J. Jason Wentworth October 4, 2018, 4:23

          Yup–and I have found it curious that many METI opponents *don’t* (which I’m glad of) oppose the idea of humanity dispatching its own Bracewell probes, which are possibly the most blatant form of METI (short of an inhabited starship entering orbit around the inhabited planet of interest) that there could be. One probe to one star might not hit the SETI jackpot, but Bracewell proposed launching 1,000 probes, and if fast “Sun-diver” sail probes could be mass-produced (Breakthrough Starshot suggests that possibility), we could “spray” the surrounding stars with far more than that, increasing the odds of attracting attention. Also:

          A civilization might miss a METI radio or laser signal (particularly one like the short-duration ones that we’ve broadcast thus far, and which folks like Douglas Vakoch are planning to do on a larger scale). But a signal-emitting (especially “echo-repeating”), optically- and/or infrared-observable example of alien spacecraft technology in a civilization’s celestial back yard would be glaringly obvious, even if it flew through their system rather than braking into circumstellar orbit.

          • ljk October 4, 2018, 12:34

            A radio METI moves at the speed of light (and radio waves), covering a wide swath of the galaxy and continuing outward indefinitely, although with an exponentially decreasing signal strength, of course.

            By comparison, an interstellar vessel is very confined in both space and time, moving much slower than light speed (as I assume such probes from the Sol system will do at least in the early days). It would also be narrowly focused on a single star system, perhaps even to one planet (or moon) in particular.

            However, while I can see a radio signal – or even a light (laser, infrared) signal – being missed for various reasons, a physical interstellar probe may have a much better chance of being detected. Especially if we do go with the lightsail concept and have both a powerful laser and a huge sail to contend with.

            This is why I have long advocated that all deep space vessels carry information about its origin and its makers for any and all recipients, be they future humans or ETI. Certainly we would appreciate such a gift if an alien starcraft entered our Sol system without prior announcement, at the least to quell fears of sinister intent for a species that has been long weaned on invading alien marauders.

            • J. Jason Wentworth October 4, 2018, 22:20

              *Nods* Duncan Lunan, John Macvey, Chris Boyce, Dr. Terence Nonweiler, and the other ASTRA (Association in Scotland To Research into Astronautics) members, in two books (Lunan’s “Man and the Stars” and Boyce’s “Extraterrestrial Encounter” [which deals extensively with Bracewell and Von Neumann probes]), went into considerable detail in designing “First Contact Packs”–and various contact scenarios–for human-made future starprobes and starships.

        • Harold Shaw October 4, 2018, 10:04

          SETI will continue to expand what is searched for as our technology improves. SETI has been looking for the things that we have been able to look for, which may be frustrating but also understandable.

          • ljk October 4, 2018, 13:18

            SETI could have looked for light signals and astroengineering projects decades earlier. A few did, but the mainstream SETI people stuck almost exclusively with radio until the later 1990s, when Optical SETI was finally accepted – and then they tried to make it look like they had always welcomed the search for alien laser/infrared signals, which was not the reality.

            See here for that history:


      • Antonio October 3, 2018, 17:56

        Huh? Where is the anthropomorphism and narcissism?

        • Harold Shaw October 4, 2018, 9:44

          For METI to be the ultimate way to search, you need to make some assumptions that eliminate the potential for false negatives, an ETI that receives a signal and does not respond. Those assumptions are that all ETI are as motivated to communicate as humans and that they would find us worth talking to.

          Please do not take this to mean METI isn’t worth pursuing, just that we need to be less emotional when designing METI strategies. Imo, METI is where SETI was decades ago; where experiments are being designed by people overly emotionally invested in the outcome.

          • Ron S. October 4, 2018, 11:16

            “we need to be less emotional when designing METI strategies”

            Good luck with that! When the cost/benefit data is lacking almost the only thing to drive us, in any pursuit, is emotion.

          • ljk October 4, 2018, 13:35

            Name me a science where its human practitioners are not emotionally invested in the outcome.

            • J. Jason Wentworth October 4, 2018, 22:24

              Emotion, curiosity, and wonder are not to be despised; without them, no exploration, whether physical or purely intellectual, would ever take place.

              • Matt M. October 30, 2018, 19:09

                Wonder what would happen if those aliens were devoid of those human traits then…

                Personally, I don’t share the (sometimes intense) need to contact aliens, it looks to me like trying to reach gods or angels but in a non-theological way – requires some technological means and scientific equations, but is still immersed in hope and faith.

  • James Stilwell October 3, 2018, 4:02

    There may be a cosmic life-wave in operation…
    Stars take time to develop…
    planets take time to develop…
    civilizations take time to develop…
    faster that light civilizations take time to develop…
    There may be only 3 or 4 civilizations in the Milky Way galaxy…
    That might mean there are trillions of civilizations in the universe…
    cosmic patience is a virtue…

    • ljk October 3, 2018, 13:48

      Assuming humanity survives long enough to find them.

  • AlexT October 3, 2018, 4:16

    “scooping one 8-ounce glass out of the Earth’s ocean, looking and seeing if you caught a fish.”
    This argument, very speculative and can proove exactly opposite things that autor means…
    For example if your target to find whale using 8-ounce glass – you do not have any chance to achieve your target even if you have endless amount of time, but if you will look inside this glass using microscope – you will definitely find lot of life…
    So probability of success depends on the corrcet choose of an instruments and a target.
    I suppose that modern SETI uses a wrong instruments for a wrong targets…
    The present SETI instruments is better to use for Radio Asyronomy to build our Universe Radio Spectrum 6-dimentions map (6 dimensions , I mean X,Y,Z, time, frequency, signal power)
    I suppose also that “water hole” frequency (1420MHz) for initial SETI was the bad choice, with bad arguments to choose this value.
    To look for technological footprint of distant civilisation we can/have to use only our own example – i.e. choose for listening the frquency range that was initally adopted by homo sapience i.e. Long-Short waves (0-30MHz), there were lot of high power broadcast stations that are/were sending high power RF signals around the Universe for long time. Those frequencies are easier to use for new born industrial civilization.
    And opposite on our own example – we can see that with technological development of our own civilization we are going now to cut of “shortwave” broadcast and use lower power for radio communication in same time moving higher and higher in frequency range (with significantly lower power).

    • hiro October 4, 2018, 17:10

      We will probably find more plastic particles than bacteria in that 8 oz glass of sea water (not sure it’s true but it should be close enough), this is still counted as a sign of intelligent life in a certain way.

      • AlexT October 6, 2018, 11:01

        This does not chage the fact that “scooping a fish by glass” – it is very poor and demagogic argumentation.

  • Paolo October 3, 2018, 4:45

    An highly intelligent lion, a really extraordinary one which has developed the concept of “concept” and a few others (object; space between objects; lion; prey; forest; quest) would run up a hill, stare at the full moon and think: “there must be lions and preys on that object; let’s devise a way to smell their odour and to go through the forest that separates here from there”. We are inevitably bound to our concepts.

    • Antonio October 3, 2018, 11:00

      False analogy. For a long time now, we not only make concepts, like religious or magical-thinking people did, but we also check them (science). Any space-faring civilization will be of the science type (because you can’t go out there or communicate without science).

      • ljk October 3, 2018, 13:50

        Well, humans did assume such things long before they became even remotely scientific and certainly lacking in the technology either to find aliens or travel into space. However, you are correct that the ones who make the effort for real will have to be scientific – assuming what we think of as science is relatively universal.

      • Paolo October 4, 2018, 7:28

        Facts-checking is indeed a concept. You, Sir, assume that it is an “ultimate” concept, one that cannot be surpassed by a further development. It’s exactly the same frame of mind of the best phisicists of the world who gathered in Paris at new year’s eve 1900, to toast to the “science that has already discovered all”.

    • ljk October 3, 2018, 13:53

      Now you have me wondering what do lions think of the Moon, assuming they really notice it at all.

      • Paolo October 4, 2018, 7:32

        Now, Sir, scale up the iatus that you probably feel of one of two degrees of magnitude… Impossible, isn’t it?

        • ljk October 4, 2018, 13:19

          Okay, what is an iatus?

          • Paolo October 5, 2018, 7:33

            Sorry, a gap. Consider the gap between their “feeling” of the moon, and yours. You have – say-10 things they don’t notice (mass; material;distance;sphere;asteroids;moon landing;and so on). Now imagine that there are a hundred things that you don’t notice, because you have no concept and no experience of…

  • John Donaldson October 3, 2018, 12:37

    Bayes law would indicate that we are the only civilization currently in existence. Supposing that there are a vast number of galactic or other-wise widespread civilizations, Bayes law indicates that we should be a member of that observer group. Bayes law also indicates that we are probably near a population bottleneck.

    • ljk October 4, 2018, 13:28


      Bayesian Approach to SETI

      Press Release – Source: astro-ph.IM

      Posted October 2, 2018 9:37 PM

      The search for technosignatures from hypothetical galactic civilizations is going through a new phase of intense activity. For the first time, a significant fraction of the vast search space is expected to be sampled in the foreseeable future, potentially bringing informative data about the abundance of detectable extraterrestrial civilizations, or the lack thereof.

      Starting from the current state of ignorance about the galactic population of non-natural electromagnetic signals, we formulate a Bayesian statistical model to infer the mean number of radio signals crossing Earth, assuming either non-detection or the detection of signals in future surveys of the Galaxy.

      Under fairly noninformative priors, we find that not detecting signals within about 1 kly from Earth, while suggesting the lack of galactic emitters or at best the scarcity thereof, is nonetheless still consistent with a probability exceeding 10 % that typically over ∼ 100 signals could be crossing Earth, with radiated power analogous to that of the Arecibo radar, but coming from farther in the Milky Way.

      The existence in the Galaxy of potentially detectable Arecibo-like emitters can be reasonably ruled out only if all-sky surveys detect no such signals up to a radius of about 40 kly, an endeavor requiring detector sensitivities thousands times higher than those of current telescopes.

      Conversely, finding even one Arecibo-like signal within ∼ 1000 light years, a possibility within reach of current detectors, implies almost certainly that typically more than ∼ 100 signals of comparable radiated power cross the Earth, yet to be discovered.

      Claudio Grimaldi, Geoffrey W. Marcy
      (Submitted on 2 Oct 2018)

      Comments: Published in PNAS ahead of print October 1, 2018. Preprint has 13 pages, 7 figures + 7 pages of Supplementary Information with 5 figures

      Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Data Analysis, Statistics and Probability (physics.data-an)

      DOI: 10.1073/pnas.1808578115

      Cite as: arXiv:1810.01207 [astro-ph.IM] (or arXiv:1810.01207v1 [astro-ph.IM] for this version)

      Submission history

      From: Claudio Grimaldi

      [v1] Tue, 2 Oct 2018 12:43:03 GMT (723kb,D)



  • ljk October 3, 2018, 12:44

    Time to bring up this online book on the history of SETI again:


    In summation, in the early days of SETI, the Americans tended to build search instruments (predominantly radio telescopes) and assume the aliens they might find will be similar to humanity, if just a little more advanced technologically. And signaling into the galaxy, of course.

    The Soviets, on the other hand, were much more curious about how aliens might really behave. They did not assume the galaxy consisted of Star Trek type aliens, or humanoids with a few funny external features.

    It was not until 1987 that a book came out critical of the then current approach to SETI for the reasons stated above.

    I know SETI has always been hampered by a combination of meager budgets, begging for telescope time, and both professional and cultural ridicule. However, that does excuse the fact that we need better and more expansive methods to search for beings who are both likely very far away (if you say they are here, prove it with solid evidence, thank you) and probably unlike us in many key respects.

    • ljk October 4, 2018, 13:34

      Actually does NOT excuse the fact…

    • AlexT October 5, 2018, 2:59

      I am sure we have to invest more efforts to development of space exploration technology in the beginnig our Solar System is huge enough for some long period of time.
      I am sure too that SETI efforts are much less important for us than space exploration and should be left with limited budget :-)

      • Alex Tolley October 5, 2018, 14:27

        If, a big IF, SETI found evidence of ET, it would be interesting how Earth nations would respond. Which areas of funding would increase? It might take several directions, including space exploration and colonization.

        • AlexT October 6, 2018, 11:21

          1. I suppose that ETI discovery – will change almost nothing in our lifes , till ETI will bring us “a Newest Testament from some galacting mounth Zion”. Most probably involved in this discovery scientists will get the Noble price – it will be most significant thing we (humanity) will gain from this finding :-)
          2. I am sure that in this case – every reaction should follow after inital action (or discovery) and should be adopted accordingly discovery facts, all other speculations (if-if-if) are good subject for science fiction story.

        • ljk October 8, 2018, 8:46

          Unlike most American scientists with Arecibo past and present, China has officially declared SETI as one of the main goals for its new FAST radio telescope, now the largest single dish on Earth. In fact they have declared that China is striving to be the first nation to detect an alien transmission.

          In a bit of irony, the Green Bank Radio Observatory, where the first modern SETI effort was made in 1960 by Frank Drake with Project Ozma, long downplayed its historic role in the search for alien signals. Then it lost NSF funding and now it provides tours where Ozma and more recent SETI efforts are the highlight.

          Money talks. Perhaps when our SETI efforts finally bear fruit we can discover if this is a universal trait among civilizations.

          • AlexT October 9, 2018, 2:19

            I supose that SETI efforts will never bring any ETI fruit…

            • ljk October 9, 2018, 12:55

              Only if we do not make the effort.

              Giving up is always easy, initially.

              • AlexT October 11, 2018, 4:31

                SETI can be left to supported by private investors and radio amateurs, i.e. to the people who dreams to get usable information from ETI.
                I think SETI as it is today try to fing the desired things in wrong place, by the wrong tools and methods.
                My opinion – It will be better to spend any etra money to space exploration development, it is not “give up” – the space exploration is alternative method to find ETI, and it does not suffer from the modern SETI bias.

  • ole burde October 3, 2018, 14:14

    Seti has its natural place in the general framework of Space Exploration : in a relatively short time we will have a reasonable chance of telescopes becoming powerfull enough to find chemical evidence of life on an exoplanet , OR to find the lack of same in places where it could have existed ……in the first case we will have the perfect targeting mecanism for SETI , in the second we might eventually transfer the funding to research into automated seeding of life wherever possible

  • ljk October 10, 2018, 17:23

    NASA Should Expand the Search for Life in the Universe and Make Astrobiology an Integral Part of its Missions, Says New Report

    Press Release – Source: NAS

    Posted October 10, 2018 10:53 AM

    To advance the search for life in the universe, NASA should support research on a broader range of biosignatures and environments, and incorporate the field of astrobiology into all stages of future exploratory missions, says a new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine.

    Astrobiology, the study of the origin, evolution, distribution, and future of life in the universe, is a rapidly changing field, especially in the years since the publication of NASA’s Astrobiology Strategy 2015. Recent scientific advances in the field now provide many opportunities to strengthen the role of astrobiology in NASA missions and to increase collaboration with other scientific fields and organizations. The report finds that these changes necessitate an updated science strategy for astrobiology.


  • Michael Fidler October 14, 2018, 11:19

    Could this be the reason ET civilizations are not aggressive blood thirsty monsters?


    “We’d also need to eat an almost exclusively vegan diet, as keeping livestock in Martian conditions would be far too difficult.”


    One other good reason that ET would not go out of their way to contact us.

    We are going to eventually be able to observe distant planets in great detail, either super size telescopes or solar gravity scopes. ET would of observed us long ago and seen the many wars and cults that sacrificed to deities from the heavans. The Mayan beating heart being a prime example. Just look at the example that we sent out to them…

    They are probable scared we will cut their heart out and electrocute them on the large temple! 😨

    • AlexT October 14, 2018, 12:31

      If “homeware manufacturer and retailer Hillary’s” write this , so it should be exactly like he/she say, no any doubt…
      I am afraid we will never colonize Mars with such experts, or maximum will colonize Mars on the puctures of homeware store and web page…

      • Michael Fidler October 14, 2018, 16:08

        They will probable be making lab meat anyway…
        I thought you might like the blood thirsty monster – The image of a Mayan priest in Quetzalcoatl dress cutting out the still beating heart and offering it to the gods. I’m sure any aliens watching that would be horrified of humans. What’s fascinating is that the Arecibo message taken at face value looks very similar. Now that’s right out of Heavy Metal!

        Whey are we not sending beautiful pictures of our earth and the life on it instead of something that can be misinterpreted as a threat?

        • AlexT October 15, 2018, 3:09

          Yes, there is very unpleasant life forms evolved on the Earth, so what?
          Should we feel ashamed of the fact that wolfs eat sheeps and people die of cancer or even of flue?

        • ljk October 30, 2018, 16:26

          Not knowing our targets, we might send just about anything that could be misinterpreted as a horrific threat.

          There are images on the Voyager Interstellar Record that if the recipients resemble some of the animals depicted among its 118 images, the ETI could be shocked, offended, etc. Assuming they have such behavioral traits.

          Punch magazine once did a satirical story on the Pioneer Plaque being interpreted by widely different ETI. One that I remember had the aliens resembling the pulsar map, which was positioned in such as way that the beings saw as an incredibly rude gesture.

      • Michael C. Fidler October 21, 2018, 23:23

        I could just see 30 foot corn stalks and 2.5 foot corn cobs on Mars. ;-}