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A ‘Census’ for Civilizations

We’ve been talking about the Colossus project, and the possibility that this huge (though remarkably lightweight) instrument could detect the waste heat of extraterrestrial civilizations. But what are the chances of this, if we work out the numbers based on the calculations the Colossus team is working with? After all, Frank Drake put together his famous equation as a way of making back-of-the-envelope estimates of SETI’s chances for success, working the numbers even though most of them at that time had to be no more than guesses.

Bear in mind as we talk about this that we’d like to arrive at a figure for the survival of a civilization, a useful calculation because we have no idea whether technology-driven cultures survive or destroy themselves. Civilizations may live forever, or they may die out relatively quickly, perhaps on a scale of thousands of years. Here Colossus can give us useful information.

The intention, as discussed in a paper by Jeff Kuhn and Svetlana Berdyugina that we looked at yesterday (citation below), is to look out about 60 light years, a sphere within which we have numerous bright stars that a large instrument like Colossus can investigate for such detections. We’re making the assumption, by looking for waste heat, that civilizations living around such stars could be detected whether or not they intend to communicate.

Screenshot from 2017-05-17 08-41-14

Image: Figure 1 from Kuhn & Berdyugina, “Global Warming as a Detectable Thermodynamic Marker of Earth-like Extrasolar Civilizations: The case for a Telescope like Colossus.” Caption: Man-made visible light on the Earth in 2011. From DMPS/NASA. The brightest pixels in this 0.5 × 0.5 degree resolution map have a radiance of about 0.05 × 10−6 W/cm2/sr/micron. Credit: Jeff Kuhn/Svetlana Berdyugina.

Let’s take the fraction of stars with planets as 0.5, and the fraction of those with planets in the habitable zone as 0.5, numbers that have the benefit of Kepler data as some justification, unlike Drake’s pre-exoplanet era calculations. Kuhn and Berdyugina have to make some Drake-like guesses as they run their own exercise, so let’s get really imaginative: Let’s put the fraction of those planets that develop civilizations at the same 0.5, and the fraction of those that are more advanced than our own likewise at 0.5. These numbers operate under the assumption that our own civilization is not inherently special but just one of many.

Work all this out and we can come up with a figure for the fraction of civilizations that might be out there. But how many of them have survived their technological infancy?

Let me cut straight to the paper on the outcome of the kind of survey contemplated for Colossus, which is designed to include “a quantifiably complete neighborhood cosmic survey for [Kardashev] Type I civilizations” within about 20 light years of the Sun, but one that extends out to 60 light years. In the section below, Ω stands for the ratio of power production by an extraterrestrial civilization to the amount of stellar power it receives (more on this in a moment).

From the paper:

…current planet statistics suggest that out of 650 stars within 20 pc at least one quarter would have HZEs [Habitable Zone Earths]. Assuming that one quarter of those will develop Ω ≥ 0.01 civilizations, we arrive at the number of detectable civilizations in the Solar neighbourhood ND = 40fs, where fs is the fraction of survived civilizations (i.e., civilizations that form and survive). Hence, even if only one in 20 advanced civilizations survive (including us at the time of survey), we should get a detection. Taking into account the thermodynamic nature of our biomarker, this detection is largely independent of the sociology of detectable ETCs.

Independent because we are not relying on any intent to communicate with us, and are looking for civilizations that may in fact be advanced not far beyond our own level, as well as their more advanced counterparts, should they exist.

Suppose we detect not a single extraterrestrial civilization. Within the parameters of the original assumptions, we could conclude that if a civilization does reach a certain level of technology, its probability of survival is low. That would be a null result of some consequence, because it would place the survival of our own civilization in context. We would, in other words, face old questions anew: What can we do to prevent catastrophe as a result of technology? We might also consider that our assumptions may have been too optimistic — perhaps the fraction of habitable zone planets developing civilizations is well below 0.5.

But back to that interesting figure Ω. The discussion depends upon the idea that the marker of civilization using energy is infrared heat radiation. Take Earth’s current global power production to be some 15 terawatts. It turns out that this figure is some 0.04 percent of the total solar power Earth receives. In this Astronomy article from 2013, Kuhn and Berdyugina, along with Colossus backers David Halliday and Caisey Harlingten, point out that in Roman times, the figure for Ω was about 1/1000th of what it is today. Again, Ω stands for the ratio of power production by a civilization to the amount of solar power it receives.

The authors see global planetary warming as setting a limit on the power a civilization can consume, because both sunlight from the parent star as well as a civilization’s own power production determine the global temperature. To produce maximum energy, a civilization would surely want to absorb the power of all the sunlight available, increasing Ω toward 1. Now we have a culture that is producing more and more waste heat radiation on its own world. And we could use an instrument like Colossus to locate civilizations that are on this course.

In fact, we can do better than that, because within the 60 light year parameters being discussed, we can study the heat from such civilizations as the home planet rotates in and out of view of the Earth. Kuhn and Berdyugina liken the method to studying changes of brightness on a star. In this case, we are looking at time-varying brightness signals that can identify sources of heat on the planet, perhaps clustered into the extraterrestrial analog of cities. A large enough infrared telescope could observe civilizations that use as little as 1 percent of the total solar power they intercept by combining visible and infrared observations. A low value of Ω indeed.

Screenshot from 2017-05-17 08-41-55

Image: Figure 3 from the Kuhn/Berdyugina paper “Global Warming as a Detectable Thermodynamic Marker of Earth-like Extrasolar Civilizations: The case for a Telescope like Colossus.” Caption: Fig. 3. Expanded view of a representative North American region illustrating temperature perturbation due to cities (left, heated cities are seen in red) and corresponding surface albedo (right). From NEO/NASA.

You can see what a challenge this kind of observation presents. It demands, if the telescope is on the ground, adaptive optics that can cancel out atmospheric distortion. It also demands coronagraph technology that can distinguish the glow of a working civilization from a star that could be many millions of times brighter. And because we are after the highest possible resolution, we need the largest possible collecting area. The contrast sensitivity at visible and infrared wavelengths of the instrument are likewise crucial factors.

I’ll refer you to “New strategies for an extremely large telescope dedicated to extremely high contrast: The Colossus Project” (citation below) for the ways in which the Colossus team hopes to address all these issues. But I want to back out to the larger view: As a civilization, we are now capable of building technologies that can identify extraterrestrial cultures at work, and indeed, instruments like Colossus could be working for us within a decade if we fund them.

We can add such capabilities to the detection of non-technological life as well, through the search for biomarkers that such large instruments can enable. More on that tomorrow, when I’ll wrap up this set on Colossus with a look at photosynthesis signatures on exoplanets. Because for all we know, life itself may be common to habitable zone planets, while technological civilization could be a rarity in the galaxy. Learning about our place in the universe is all about finding the answers to questions like these, answers now beginning to come into range.

The Colossus description paper is Kuhn et al., “Looking Beyond 30m-class Telescopes: The Colossus Project,” SPIE Astronomical Telescopes and Instrumentation (2014). Full text. The paper on Colossus and waste heat is Kuhn & Berdyugina, “Global warming as a detectable thermodynamic marker of Earth-like extrasolar civilizations: the case for a telescope like Colossus,” International Journal of Astrobiology 14 (3): 401-410 (2015). Full text.


Comments on this entry are closed.

  • ole burde May 17, 2017, 14:47

    ”We’re making the assumption, by looking for waste heat, that civilizations living around such stars could be detected whether or not they intend to communicate.” …that would seem to be a very problematic assumtion . Waste heat can only be distinguished form other heat sources if you know exactly what the these other sources are, and how they interact with each other .

  • Larry Kennedy May 17, 2017, 15:11

    Well they’re certainly in good company. Carl Sagan likewise set many factors in the Drake equation unrealistically high and then neutralized it in the last term.
    Kuhn and Berdyugina are setting the early terms unrealistically high and then stating that it justifies a pessimistic last term assuming a negative search.

    • Jeff Kuhn May 17, 2017, 23:20

      Unrealistically large?
      When we think back 25 years to earlier days of the Drake “equation” we should note that there is only one term that we’ve qualitatively learned *much* more about, today — its the f_p – fraction of stars with planets, term. In the old days, before exoplanets took over astronomy, we speculated that this number might be “optimistically” 0.001 (or even less). But we now know that f_p is actually much much bigger — more than two orders of magnitude larger. As a grad student in the late ’70s I remember one of the astronomy greats, Lyman Spitzer, once commenting in his graduate course that he thought “planet formation is likely to be exceedingly rare”. Of course we didn’t have better information back then, but we know now that a kind of cosmo-exo-principle, that “we’re not special” really does seem to bear fruit every time we reach sensitivity levels that are good enough to explore habitable zone exoplanets. So, while none of us can logically say how to apportion our uncertainties against these unknown ‘Drake’ terms, we do have defensible arguments for our rather minimal assumptions.

      • Larry Kennedy May 18, 2017, 11:15

        I’ve been around long enough to read these arguments since the Drake equation itself. I feel very safe saying that for all who would’ve believed .001 many more would’ve believed .5 or higher. Of course both were only guessing since we had little real data. I would’ve found the .001 arguments about as compelling as the overly optimistic estimates now.

      • Spaceman May 19, 2017, 9:07


        My interest in astronomy began when I was about 6 years old in the mid 1980s. At that time, I remember reading then that we did not know if there are “other solar systems” and that it might still be many years before telescopes would be capable of detecting them or ruling out their existence. Fast forward 3 decades and I think we do pretty much have the value for Fp and it is close to 1. I think with space-based microlensing and additional transiting survey data post-Kepler, we will know Fp to an even higher degree of accuracy. What are your thoughts on the subsequent terms in the Drake equation? The Fne seems like it could be around 1 since there are moons in our solar system with liquid water, an energy source, and organic molecules. However, I personally think the Fl value will turn out to be very small because abiogenesis here may have been a fluke event such that even simple life, let alone anything more complex, may arise only once per 1000 large galaxies.

  • hiro May 17, 2017, 15:51

    Using “creative estimate” shows that if one fails to detect any artificial signature in the radius of 2000 light-years during a period of 500,000 years then the rare-Earth hypothesis might apply to this (only) galaxy. There is no way to know anything (positive or negative) in the Virgo, Coma, and the Shapley super-group etc…

    • spaceman May 19, 2017, 18:31


      You make an interesting point; however, what leads you to think that the Rare Earth hypothesis would apply to some galaxies more than others?

      • hiro May 20, 2017, 17:53

        A comparison between galaxy superclusters such as the Virgo supercluster (we’re in the backyard corner I think) vs Horologium or Shapley Concentration show to big different amount of the richness of material. Then there are the Sloan Great Wall and other Great Wall around or more than 7 billion light-years from here; of course the probability of life appearing in these regions is much higher than the probability of some galaxies which are close to the boundary of Great Voids. Therefore, it’s reasonable to give an “educated guess” that if there is one habitable planet in the Virgo supercluster then there should be at least one or more in somewhere else such as the Horologium & Shapley super-group. The rare Earth hypothesis can’t be generalized to the rest of the visible Universe.

        I also have an hypothesis, it’s very simple: if we are alone in this entire Universe then we’re living inside some high qubit (> 300 qubits) universal quantum computer’s simulation. Otherwise, there are ETs out there.

        • Spaceman May 21, 2017, 21:49


          Interesting hypothesis about simulations, would you care to explain it in more detail? :)

          • hiro May 22, 2017, 16:27

            AI’s fancy empire game? The idea that we have the entire universe to conquer is just too good to be true.

  • james stilwell May 17, 2017, 18:01

    When we look at a star system 500 light years away we are seeing the system 500 years ago…Humanity has come a long way these past 500 years…Astronomers on such a system seeing us today would be seeing earth 500 years ago…Hopefully someone will crack the FTL barrier and like Arthur C. Clarke suggested, we may go to the stars aboard spacecraft designed by an alien race…Tsiolkovsky hinted at this in his interesting book, The Will of the Universe…

    • ljk May 22, 2017, 9:33

      And why would ETI who can do FTL travel just hand over this technology to us or beings like us?

      • hiro May 22, 2017, 16:25

        Hehehehe, so that we can wipe them out to extinction and then colonize the galaxy & universe right?

  • Joe May 17, 2017, 19:30

    “We have no idea whether technology-driven cultures survive or destroy themselves.” A third possibility is that a technology driven culture might rise and decline as part of a historical cycle where the level of technology never quite reaches the level required for interstellar travel. It’s not hard to envision a future here on Earth where insurmountable problems limit advances in space exploration, and where the human race survives at a lower level of technology. An extreme example of this idea is the SF novel “1632” where aliens, via time travel, force the residents of a small town in West Virginia to use use failing 20th century technology to replicate sustainable 19th century technology. It’s not pleasant, but they survive.

    • Robert May 19, 2017, 15:13

      Even a 19th century civilization should leave significant thermal signals as the heat island effect of cities would still be in effect. Also, 19th century technology if explored, refined and advanced as far as applications goes, could do much that it never had the chance to do as it was replaced by more modern technologies. I mean by that certain new devices and applications would be inherently 19th century in character while doing things never envisioned in the 19th century. An example might be long range steam cars, great airships running regular routes between cities or an hyper refined telegraph system linking private users to send messages instantly like the internet but without the modern electronics. In fact, they had transatlantic telegraphy, telephony and even electricity. No need it be uncomfortable at all.

      • ljk May 22, 2017, 9:32

        It makes one really wish they had gone ahead with that plan to dig huge geometric symbols in the Sahara Desert, fill them with oil, then light them on fire to be seen by others worlds (hint Mars) so their inhabitants would know there are creatures on Earth who can at least do some math.



        • Robert May 22, 2017, 14:17

          But then they would have laughed at us for not figuring out how to do it without burning half the planets oil reserves. The earthwork art of Robert Smithson comes to mind.


          • ljk May 23, 2017, 10:10

            You assume they would understand petroleum or care that we would use it in such a manner. If anything I consider that much of what we do with so much gasoline on a daily basis in regular life to be the real laughable and wasteful effort.

            • Robert May 25, 2017, 12:35

              We use it because we have a choice between living in an advanced technological civilization or not. The alternatives are not ready to fully take over but I’m waiting for the era of Hydrino power myself.

  • Spaceman May 17, 2017, 21:33

    Fascinating project. The more diverse our methods of looking for intelligent life, the better our chances of detecting it there will be. This assertion, however, is somewhat dependent on how common intelligent life is in our galaxy. I personally tend to lean in the direction of the Rare Earth hypothesis, and so I will not be surprised if these searches come up dry. I suspect that there may only be 1 to 10 planets with complex life in our galaxy. Even though ET life is probably rare, we should still look for it!

    • ljk May 23, 2017, 10:16

      We neither know enough nor have we done enough when it comes to searching for alien life to make any real assertions about its existence or lack thereof in this galaxy.

      For starters SETI needs to really start breaking out of its decades old paradigm (radio looking at Sol-type star systems) and start making real efforts beyond the largely token ones I have seen so far.

      Here is a primer on the possibilities for SETI (and METI). That it is from 1992 and so many concepts are still waiting to be done properly says a lot about human efforts to search for alien life, not much of it good:


  • Alex Tolley May 17, 2017, 21:49

    I take issue with the authors’ statement:

    Such a program could tell us just how fragile advanced
    life is, i.e., statistically, how likely it is for an Earth-like
    civilization to survive.

    If they see no signal, that could mean that civilizations have a 0% survival, or that no civilizations ever developed. I do not see how they can separate these two cases. Along the same lines, even if they detect an unambiguous civ heat signature, that still won’t tell us much about survival, although such a detection would be very exciting.

    Whether they can indeed unambiguously detect a civilizational hear signature is something to be determined. It seems to me natural phenomena might easily mimic the signatures they have calculated. Using a spectrographic scope of a probe in the outer solar system pointed at Earth might well be a reasonable test of their approach that could be done quite soon.

    Let’s also speculate that such a heat signature was found, but there was no detectable biosignature. Would that imply a false positive, or that perhaps a machine civilization was present? If the latter, then why restrict exoplanets withing teh HZ, as presumably machines could colonize any suitable body, or none?

    • Joe May 18, 2017, 13:10

      I would also suggest that there could be lots of technological civilizations in the galaxy that exist in a pre-industrial state and therefore don’t give off excess heat. Human civilization up until the 19th century fit this category.

      • Alex Tolley May 18, 2017, 14:15

        Agreed. Even Ancient Roman or Chinese levels of civilization might not have produced the heat signatures needed for detection, although fires for heating in winter just might be enough of a contrast for a city heat island. But generally, I think you are correct.

    • J. Jason Wentworth May 21, 2017, 0:34

      Yes–these three sentences (“Suppose we detect not a single extraterrestrial civilization. Within the parameters of the original assumptions, we could conclude that if a civilization does reach a certain level of technology, its probability of survival is low. That would be a null result of some consequence, because it would place the survival of our own civilization in context.”) don’t make sense, even if plant and animal life were found to exist on any the planets in question. If no life is found on those exoplanets, the more likely reason is that it never *was* there, rather than that civilizations once existed there but then died out or destroyed themselves, and:

      If any of those worlds do have life, intelligent life may not have arisen, and even if it did, that’s no guarantee that technological civilizations would ever appear on such worlds. Life is not a necessity, even on planets where everything is set up “just right” to be in its favor. Chemically and energetically speaking, life is a needlessly complicated thing that doesn’t have to arise (nor does intelligence, even if life arises on any given world); in a sense, life is a solution in search of a problem. There are plenty of far simpler compounds that–on a planet with a promising organic “soup,” water, and plentiful energy sources–will satisfy the valence requirements and bring all of the various chemical compounds to their most stable, “reacted” states. Also:

      I’m not saying that we are alone in the Milky Way, or in the universe, but that it *could* easily be the case–but so could the state of affairs that we hope for (other civilizations, whether many or few), or something in between (that life could be rare or even fairly common, while ^intelligent^ life could be exceedingly rare, or even unique to Earth). Since we don’t know, we should keep looking, while being prepared for the “lonely” possibility to be the correct one (if we are alone, we can change that outcome by gradually colonizing and engaging in robotic panspermia missions [there would be no ethical problems with either one if there’s no life out there]).

  • ijv May 18, 2017, 2:14

    How does an omega of 0.04% square with estimates of Earth as a Kardashev 0.7 civilization? Shouldn’t the two be equivalent?

  • Ronald May 18, 2017, 4:31

    “Let’s put the fraction of those planets that develop civilizations at the same 0.5, and the fraction of those that are more advanced than our own likewise at 0.5.”.
    “We might also consider that our assumptions may have been too optimistic — perhaps the fraction of habitable zone planets developing civilizations is well below 0.5.”.

    There is the crux: I think that Kuhn & Berdyugina are ridiculously optimistic about the chances of advanced intelligence, and in particular technological civilization. Anyone can come up with an adapted Drake formula with arbitrary fractions. However, it is the realism of these numbers, and the actual testing of them in practice, in which the real value is.

    It seems as if some people want to make an unrealistic giant leap. I would say, one step at a time and prioritize: let’s first get a good picture of the occurrence of terrestrial planets in the HZ, in particular of solar type stars, then let’s try to get bio-signatures, to find out how (un)common life is.

    Martin Fogg, the terraforming expert, classified terrestrial planets in 3 categories: habitable, biocompatible, (easily) terraformable.
    I think that a prioritization reflecting something like this would make a lot of sense.

  • Albert A Jackson May 18, 2017, 9:39

    As in all these papers one would hope someday someone would list all the possible uncertainties in a more rigorous quantitative manner than even done here. It’s had to draw conclusions if there is not enough definitive fuzz surrounding a Fermi-Question topic. I am left unconvinced that has been done in this study.

  • DCM May 18, 2017, 11:59

    If we do locate what appears to be a civilization we should avoid going there.
    Possibly we can send a probe programmed to orbit the area at a certain distance, close enough to examine the place optically and otherwise. But of course it will take a long time to get there even with a superfast ion drive and a long time to get information back to us. Still, that would be the safest thing.

    I’m not optimistic, though. We just don’t have enough information and won’t for thousands of years to be able to make solid generalizations. Here, patience and systematic terraforming and world building are in order.

    • Jeff Kuhn May 18, 2017, 21:00

      Some loose threads…
      Yes, there are oh so many ways to miss a civilization by looking just for heat. Clearly the challenge is to devise a “remote sensing” signal that does better… Mean temperature, and temperature gradients across an exoplanet surface *will* be measured, and on a statistically interesting number of exoplanets. Corresponding atmospheric molecular biomarkers are almost as easy as temperature when we get to Colossus-size telescopes. Interesting (i.e. “non-natural”) mean surface albedo variations (think “canals”) might end up being our most glaring clue for exocivilizations that terraform or most efficiently use stellar energy to manage planetary-scale natural resources, (as ELF/Colossus will measure). As to the question of geothermal confusion and false positives we have other hooks…for example the temperature or surface distribution of geothermal sources might be an important discriminant. Of course, we’ll probably never learn much about advanced life on a Venus-like planet or an Enceladus moon with these tools. Nevertheless, we humans *are* rather clever, and we *do* live in an optimistic universe of infinite possibility.

      Thanks all. A rousing discussion. Future questions or thoughts are welcome by email to the PLANETS/ELF/Colossus participants (or join this merry band!).

  • hiro May 20, 2017, 18:03

    This might be off topic, if some advanced civilizations had capabilities to produce power from nuclear fusion cheaply (the cost of building 1 TW fusion power plant is quite low) then would they still use solar panels to collect solar energy? The concept of Dyson swarm/shell/sphere exists only if it’s used to power something that requires huge amount of energy such that normal fusion power plants can’t reach.

    • ljk May 22, 2017, 9:39

      Or a weapon:


      Rockets didn’t get serious support and funding until the authorities realized they would make really great and devastating weapons. There is a reason the DoD has an annual budget of $670 billion and NASA has only $19 billion. Those reasons may extend across the Universe.

  • Andrew Palfreyman May 22, 2017, 10:03

    “Take Earth’s current global power production to be some 15 terawatts. It turns out that this figure is some 0.04 percent of the total solar power Earth receives.”

    I don’t think so. Total insolation is 173 PW, yielding 0.0086%.

  • ljk May 25, 2017, 13:04

    What will humanity be like in one billion years?


    This piece is terribly conservative and lacks imagination, but it has a video and we may be able to glean something from it.

  • ljk May 25, 2017, 22:11

    ‘Aliens’ asks scientists to consider – seriously – extraterrestrial life

    The main purpose of ‘Aliens’ isn’t to argue for or against the proposition that we are not alone, but to discuss the conditions necessary for life and the possibility that such conditions exist.

    By Rayyan al-Shawaf

    MAY 17, 2017

    Full article here:


    To quote:

    If at least a portion of any putative extraterrestrial life qualifies as intelligent, the chances of contact increase, as the aliens themselves may be trying to find the likes of us. However, as Martin Rees notes, there remains a distinct possibility that, should such aliens have been around longer than humans, they will have begun a transition to inorganic forms. After all, intelligent life – at least here on Earth – seems to crave yet more intelligence. In Rees’s view, “This suggests that if we were to detect ET, it would be far more likely to be inorganic: we would be most unlikely to ‘catch’ alien intelligence in the brief sliver of time when it was still in organic form.”


    Perhaps the most mind-boggling aspect of this book (and that’s saying something, given that it’s about extraterrestrial life) concerns just who at our end would make contact with aliens, should they turn out to exist. Remember Rees’s point about prospective aliens having evolved into something inorganic by the time we find them? Well, it works both ways. Indeed, Rees’s chapter is titled “Aliens and Us: Could Post-humans Spread through the Galaxy?” Both Rees and Seth Shostak (“What Next? The Future of the Search for Extraterrestrial Intelligence”) argue that by the time Earthlings and aliens locate each other, let alone meet, “we” – or some of us, at any rate – will essentially have ceased to be human. Not only that, but our (artificially engineered) evolution toward cyborgs or something silicon-based is precisely what will enable physical contact, as opposed to mere electronic communication. “Interstellar travel will only be a realistic possibility for post-humans,” asserts Rees.

    It sounds far-fetched, but if Rees and Shostak are correct, their view has at least one serious implication for the here and now. Actually, it’s equal parts serious implication and major bummer. For those of you taking succor in the belief that, even if you fail to arrange that much-desired powwow bringing together humans and aliens, your progeny will manage the feat, think again. Far from being your grandkids or great grandkids, any Earthlings who eventually rendezvous with aliens may well constitute replacements for the human race. Shostak muses that “it’s at least possible that once GAI [General Artificial Intelligence] establishes a presence on Earth, it may so dominate the planet’s resources – material, energetic and geographic – that Homo sapiens will be marginalised in the way that great apes are.”

  • ljk June 1, 2017, 9:37

    Forty years later the Wow! signal still wows SETI:


    Apparently the Wow! signal of 1977 found by the Big Ear radio telescope at Ohio State University (OSU) would be dismissed with today’s modern SETI equipment as such signals are detected quite frequently. On the other hand, I also think the recent comet explanation for the Wow! signal is yet another example of professional astronomers really reaching to keep cosmic phenomenon non-alien. Poor ice balls get blamed for everything.

    And let us not forget that in 1997 the very instrument of the then-longest running SETI project in human history was torn down so that OSU could sell the land to make way for some condos and a golf course:


    Signs of intelligent life, indeed.

    • ljk June 4, 2017, 17:59

      The online paper that says it was comets, not aliens:



      In 2016, the Center for Planetary Science proposed a hypothesis arguing a comet and/or its hydrogen cloud were a strong candidate for the source of the “Wow!” Signal. From 27 November 2016 to 24 February 2017, the Center for Planetary Science conducted 200 observations in the radio spectrum to validate the hypothesis. The investigation discovered that comet 266/P Christensen emitted a radio signal at 1420.25 MHz. All radio emissions detected were within 1° (60 arcminutes) of the known celestial coordinates of the comet as it transited the neighborhood of the “Wow!” Signal.

      During observations of the comet, a series of experiments determined that known celestial sources at 1420 MHz (i.e., pulsars and/or active galactic nuclei) were not within 15° of comet 266/P Christensen. To dismiss the source of the signal as emission from comet 266/P Christensen, the position of the 10-meter radio telescope was moved 1° (60 arcminutes) away from comet 266/P Christensen. During this experiment, the 1420.25 MHz signal disappeared. When the radio telescope was repositioned back to comet 266/P Christensen, a radio signal at 1420.25 MHz reappeared.

      Furthermore, to determine if comets other than comet 266/P Christensen emit a radio signal at 1420 MHz, we observed three comets that were selected randomly from the JPL Small Bodies database: P/2013 EW90 (Tenagra), P/2016 J1-A (PANSTARRS), and 237P/LINEAR. During observations of these comets, we detected a radio signal at 1420 MHz.

      The results of this investigation, therefore, conclude that cometary spectra are detectable at 1420 MHz and, more importantly, that the 1977 “Wow!” Signal was a natural phenomenon from a Solar System body.

  • ljk June 4, 2017, 18:04

    Are there trillions of ETI civilizations in the Universe?


    To quote:

    The possibility that we earthlings are not truly alone in the universe has gained some added credibility, thanks to a new study that coincides with NASA’s recent planetary discoveries. The research, published in the journal Astrobiology last week, suggests that more planets in the Milky Way galaxy may harbor advanced civilizations than we previously imagined.

    Study co-authors Adam Frank and Woodruff Sullivan looked at recent discoveries of potentially habitable exoplanets and considered the odds of whether sophisticated civilizations existed on them in the past or present.

    “What we showed was the ‘floor’ on the probability for a civilization to form on any randomly chosen planet,” Frank, a University of Rochester physics and astronomy professor, told The Huffington Post in an email. “If we are the only civilization in cosmic history, then that what we calculated is the actual probability nature has set. But if the actual probability is higher than that floor, then civilizations have happened before.”

    Frank says the potential number of planets orbiting their parent stars within a habitable distance is staggering.

    “Even if you are pretty pessimistic and think that you’d have to search through 100 billion (habitable zone) planets before you found one where a civilization developed, then there have still been a trillion civilizations over cosmic history!” Frank wrote. “When I think about that, my mind reels — even if there is just a one in a 100 billion chance of evolution creating exo-civilizations, the universe still has made so many of them that we are swamped by histories other than our own.”


    “We have only been looking for other intelligences for a few decades in a galaxy of unfathomable proportions,” Boston said. “Of course we haven’t found anybody yet. I think it is childish to imagine that we should somehow have started looking, and bingo, there they are! I have trouble finding my dropped contact lens in the grass. Should I then disbelieve in the reality of my contact lens?”


    “The existence of planets orbiting stars other than the sun is a 2,500-year-old question that has been entirely answered over the last 20 years,” said Frank. “We now know that every star in the night sky has at least one planet orbiting it, and many of those are in the right place for life to form.

    “Ten thousand years from now, no one will remember anything about our era except it was when we discovered this single profound fact: We live in a cosmos of planets.”

    • Alex Tolley June 4, 2017, 21:11

      That there are more planets in the HZ shouldn’t change the numbers by that much – maybe an order of magnitude. Any reasonable assignment of probabilities results in. I’ve in our galaxy at any moment from 1 (us) to many thousands or ev n millions. It is the last few terms that are uncertain and for which we still have no information.

  • ljk June 10, 2017, 13:26


    Published: 9 June 2017

    by Fraser Cain


  • ljk June 12, 2017, 13:08

    Review: Aliens

    by Jeff Foust

    Monday, June 12, 2017

    Aliens: The World’s Leading Scientists on the Search for Extraterrestrial Life
    edited by Jim Al-Khalili

    Picador, 2017
    hardcover, 240 pp.
    ISBN 9781-1-250-10963-7

    In some respects, these are good times for the Search for Extraterrestrial Intelligence (SETI). The announcement in 2015 of Breakthrough Listen, the $100-million, 10-year project funded by Russian billionaire Yuri Milner, has injected new life into an effort that has been cash-strapped for decades. Breakthrough Listen has purchased time on several radio telescopes, supported optical SETI searches for laser transmissions, and funded advances in technologies to analyze the data those efforts have collected.

    The book initially explores one of the most common questions the public has about the search for extraterrestrial life: have aliens found us already?

    But in other respects, SETI seems like a bit of a backwater in the exploding field of astrobiology. Since the mid-1990s, the number of known exoplanets has grown from effectively zero to thousands, with an increasing number similar in mass to the Earth and in orbits that place them in their stars’ habitable zones. Within the solar system, discoveries on Mars, Europa, Enceladus, and Titan have all raised the prospects that these worlds once hosted—and might still today—life, at least in its more primitive forms. SETI, by contrast, has more than a half-century of null results: if any is out there calling, we haven’t heard them yet.

    The current state of the search for extraterrestrial life, primitive or intelligent, is the subject of Aliens, a collection of essays edited by British physicist and science communicator Jim Al-Khalili. The book offers a broad overview of the issues associated with looking for life in our solar system and beyond.

    Full review here:


    To quote:

    Aliens starts with an essay by Sir Martin Rees that argues that machine intelligence may one day overtake humans on Earth and expand into the solar system and beyond. That seems an unusual way to start a collection of essays about astrobiology, but it nicely bookends with the book’s final essay by Shostak, who argues that if something like that could take place here, it could have already taken place in other worlds. Machine-based intelligence, he notes, would not have the same habitability requirements as biological-based intelligence, and need not constrain itself to certain classes of planets.

    As scientists look for habitable worlds around other stars, a quest that will drive much of astronomy for decades to come, Shostak suggests in the final pages of the book that the real action for SETI might be somewhere else entirely.

  • ljk June 14, 2017, 9:21

    The U.S. Government wants NASA to look for aliens – finally:



    From the second linked article:

    How Congress Sneakily Directed to NASA to Look for Alien Life

    This little line might change the future of space exploration and research forever.

    By Neel V. Patel on June 13, 2017

    Filed Under Aliens, Astrobiology, Donald Trump, Extraterrestrial Life, Mars & SETI

    Back in May, when President Donald Trump signed a bill to authorize funding for NASA over the 2017 fiscal year, the takeaway was that the agency was basically being told by the federal government to go about business as usual. Barring a few exceptions, Congress, with Trump’s blessing basically gave NASA exactly what it asked for, to do as it would for one more year. But there was one, small, really tiny edit into the final version of the bill which basically told NASA to, well, find aliens.

    Here’s the deal: the 2017 NASA Authorization Act has a line that, as The Atlantic observes, basically calls for “the search for life’s origins, evolution, distribution, and future in the universe.”

    So while Congress didn’t actually tell NASA it should spend the next year looking for extraterrestrial life, it is perhaps the first explicit mention on behalf of the government that part of the agency’s purpose is to learn what we can about life outside of this planet.

    The authorization act reads, under the headline ASTROBIOLOGY STRATEGY:

    “The Administrator shall enter into an arrangement with the National Academies to develop a science strategy for astrobiology that would outline key scientific questions, identify the most promising research in the field, and indicate the extent to which the mission priorities in existing decadal surveys address the search for life’s origin, evolution, distribution, and future in the universe.”

    The Act calls for NASA to enlist the help of partners from both the international community and the private sector as well.

    This is small, but critical. NASA has never really been one to enthusiastically embrace it’s work in astrobiology and investigating extraterrestrial life — at least not explicitly. But times have changed. The search for extraterrestrial intelligence (SETI) has fortified its position these days as a serious scientific endeavor. The incredible discoveries astronomers have made when it comes to understanding the potential for habitability on other worlds like Mars or Europa, or the gains made in pinpointing potentially habitable exoplanets just around the corner, have made the prospect of finding aliens more and more encouraging.

    In short, the odds of finding aliens have never been better. NASA and Congress have less of a reason to make the investigation of life outside of Earth a goal couched in scientific jargon. The government is now on record with officially endorsing an active investigation of aliens spearheaded by the world’s biggest space agency.

    • Alex Tolley June 14, 2017, 9:37

      Making it easier to redirect resources away from helping protect life on the one planet where we know life exists. Is this a sincere move or a cynical one?

      • ljk June 14, 2017, 10:09

        Do you really believe that NASA being asked to conduct exobiology is going to take away from helping Earth life? At best it will be a fraction of the current $19 billion in funding the space agency is being offered and even that whole number is pocket change compared to most other government agencies receive.

        Americans spend $2 billion annually buying chewing gum. How about we get them to stop buying gum and divert that money to more beneficial projects?

        • Alex Tolley June 14, 2017, 14:00

          NASA’s Earth sciences budget is ~ $500m, IIRC. The GOP has tried to gut this division’s work on earth observation which is involved with climate change. So yes, I do think this is a case of pointing to a shiny thing over there to distract attention and to get some space science advocates to support this direction.

          I am more than happy that NASA does more exobiology work, as long as there is funding to match it.

          Of course, the easiest funding solution would be to cancel the SLS and have industry develop the hardware to carry out missions. But pork barrel politics gets in the way.

          • J. Jason Wentworth June 14, 2017, 22:00

            Having survived the ice age of the 1970s, I’d rather see NASA’s “Earth defense budget portion” be used mostly for the following things:

            [1] Finding and tracking potentially Earth-impacting asteroids and comets;

            [2] Developing plans and testing hardware for nudging and/or destroying such bodies, including long-period comets;

            [3] Monitoring the Sun to watch for signs of another Carrington Event (and to develop the means for predicting such solar events, if possible)–these things, and studies (plus hardware tests) of how best to shield our electrical grid from such events, would also enable us to defend against an EMP attack by North Korea, Iran, or other adversaries.

            All three of these would also have “regenerative” (‘boot-strap’) effects in space science, space applications, and economic development:

            The newly-found asteroids and comets would also be potential mining targets, as well as increasing astronomical knowledge by being found and studied. (Incidentally, newly-found data from the Rosetta mission shows that significant amounts of Earth’s xenon and krypton were delivered here by comets [see: http://www.spacedaily.com/reports/Rosetta_finds_comet_connection_to_Earths_atmosphere_999.html ], so that xenon–the ideal electric thruster propellant that is rare here–could be “mined” from comets, thus making these bodies economically valuable, too.) The asteroid- and comet-nudging technologies would also be useful for mining these bodies (and would involve developing better electrical propulsion and solar sail propulsion systems to reach these bodies), and:

            The Sun-monitoring would also provide new scientific data, and the Carrington Event shielding studies and hardware tests would also be useful to the development of better lightning arrestors. If such solar events could become predictable, this could also be useful to exoplanet studies (particularly of red dwarf star habitable zone planets), for determining if they could retain significant atmospheres, what possibly life-sparking (no pun intended) electrical activity they might have at their surfaces, and so on.

            • Alexander Tolley June 15, 2017, 11:57

              There is no reason not to do all these things. However, the probability of an asteroid strike is so very, very low, whilst the effects of AGW are already very apparent and on track to be quite severe. We need monitoring so that we don’t have data gaps. No other nation has the capabilities that the US has, and that NASA leads in.

              • J. Jason Wentworth June 15, 2017, 21:17

                I don’t buy that, for multiple reasons (I don’t doubt your honesty; I just don’t accept the claims about AGW), and I live in Alaska, a “tip of the spear” location for this sort of thing:

                When I worked at our local airport here in Fairbanks, I knew the director of the RAOB (RAdiosonde OBservation) station at the airport, which launches meteorological radiosonde balloons twice a day. I asked him if they had access to all of the NOAA data sets, and they did. I then asked him if there was anything to all of the climate change chatter. He said, “If it exists, it is so slight that it is down in the statistical ‘noise.'”
                Other personal observations, along with things I’ve read, point to the same conclusion:

                There have been changes here in Alaska, but they’re nothing to panic about, and they’re cyclical and natural. 10,000 years ago it was much warmer here, and there were mighty forests that grew right up to the shores of the Arctic Ocean (their petrified remains are common there, where today only scrubby vegetation can survive up there). Also:

                Much is being said about the Arctic Ocean ice here, which is now melting sooner each year; plus, species of fish from further south are now being found here. That sounds ominous, but these things have happened here before, most recently in the 1920s. (Matt Drudge found that, and he reported about it on his website and his former radio program.)

                He also searched through old newspapers and magazines that dated back to the late 19th century, and he found that scientists as well as journalists, who noted weather changes, alternately warned about a “warming world” and a “cooling world,” at roughly 15 to 20 year intervals, on average. The 1920s warming scare, the 1970s ice age scare, and today’s warming scare are just some of the latest instances of this, and:

                I’m from Miami, and whenever there is a full Moon at perigee (which results in higher rises of the tides), the coastal road to the now-closed Miami Space Transit Planetarium (where I used to work; decades before then, my family also visited it many times when I was a boy) always has salt water from Biscayne Bay come up through the storm drains and up onto the road, because that area is close to sea level. I have heard this mentioned on the news as an example of the sea level rising because of climate change, but it is no such thing at all, because that has happened all my life whenever such exceptionally high tides have occurred there. And speaking of sea level:

                If the levels of the oceans were rising, the Maldive Islands off the coast of India–which are *at* sea level–would be underwater. But they’re still there, so the water level can’t have risen. A couple of years ago, waves were washing over the Maldives (making them more like Venice), and there were alarmed news reports that they were going to disappear soon because the sea level was rising. But the waves were only swells from a storm that was passing by some distance away, and locals said that such swells always washed over their islands when storms passed by.

                I have also seen and heard other such things. For example, three or four years ago I was reading a then-current issue of “National Geographic” magazine in the waiting room of a local physical therapy clinic that I go to each week. Now:

                One article warned that global warming would soon likely trigger another “Eocene event,” in which methane–which is trapped in large quantities in the soil and ocean bottoms of the polar regions–would be released into the atmosphere, with dire results for life on Earth. In the very same issue, there was also an article about the previous winter in the region where Mongolia is located–a winter which was so cold that the locals used their most severe term (“dzud”) to describe it; one photograph showed herders literally scraping the freeze-dried corpses of their goats off the ground! Yet a warming-triggered Eocene event was coming… Plus:

                At about that same time, two scientific survey vessels had gone down to the Antarctic Ocean, so that the scientists onboard could measure the thinning of the pack ice due to global warming. Not only did they *not* detect any thinning, but the ice was so thick–between 12 and 20 feet thick, if memory serves (it was a record high range of thicknesses)–that the ships were trapped in the ice for months! As well:

                Prince Charles of the United Kingdom solemnly declared that we have only 500 days to do something about climate change, or it will be too late to prevent its dire consequences. He made that pronouncement several years ago… Between all of these things, and the lying at which the East Anglia University researchers were caught (quoting their infamous e-mail message from memory here: “We have to strike a balance between being truthful and being effective”), plus the glee with which politicians–particularly the former Communist ones, as well as others on the left–seize upon this issue to consolidate their political power (many large companies also like the restrictions because *they* can deal with them, while their smaller competitors often cannot), this issue is the greatest scam since the Catholic Church sold indulgences to release the souls of the buyers’ loved ones from Purgatory. But:

                I do *not* advocate the diametric opposite, using up non-renewable resources willy-nilly and spreading pollution with abandon. I’m old enough to remember *real* pollution, and (except for places like Beijing and Bangkok), our air, water, and soil are cleaner than they once were, and the ever-increasing efficiency of industrial production and energy production processes are accelerating this positive trend.

                • ljk June 16, 2017, 9:31

                  Quoting from J. Jason Wentworth’s comment:

                  “I’m from Miami, and whenever there is a full Moon at perigee (which results in higher rises of the tides), the coastal road to the now-closed Miami Space Transit Planetarium (where I used to work; decades before then, my family also visited it many times when I was a boy)…”

                  I had no idea that place was gone:


                  I and I am sure many others here know of the MSTP thanks to Jack Horkheimer and his Star Gazer program on PBS Television:


                  Did you ever get to meet Jack?

                  • J. Jason Wentworth June 17, 2017, 4:47

                    Meet him? Jack was my boss! :-) There was no mistaking that unique-sounding voice. Mark Bennett (the planetarium’s last director, who is featured in the “USA Today” article whose link you posted–Thank You!) was my immediate supervisor (he was in charge of the laser shows back then).

                    All of us spent many hours “flying” that old Spitz Labs star projector. (We had a poster in the back room–created by an early planetarium employee–that was called, “The Pilots of the Planetarium,” and it showed the levels of advancement as a console operator racked up ever-more “flights.” The last phase was a “Transcendental Ace,” who was sitting in the corner of an asylum room in a strait jacket, pumped full of psychiatric drugs…) As Mark says in the article, running the shows in that planetarium–unlike in newer ones–was an almost totally manual operation (only the slides were advanced automatically by a “click track” channel on the audio tape, but sometimes it balked, and we had to take over manual control of the slides, too).

          • ljk June 15, 2017, 8:51

            The way things are going with the SLS, and if Musk and Besos accomplish their own private space plans, NASA’s new big rocket may knock itself out of existence.

            In the event that the US does gut its climate science agencies, are the Europeans able to make up the slack, if not already? I am not hoping this will happen, I am just thinking of contingency plans.

            • J. Jason Wentworth June 15, 2017, 10:33

              I hope so, because not only is the SLS unnecessary, far too expensive, and keeping the outmoded segmented SRB technology going for no good reason, but the vehicle’s weight–with its two huge solid boosters–is driving the crawler transporters to their demise far sooner than need happen. I’d much rather see the crawler transporters “given a break,” and see the SLS’s Shuttle ET-diameter tankage used for something else which (like the Saturns) could be transported while empty, so that the crawler transporters won’t be overly-burdened.

              The tankage could be used for a “Saturn-Lite”-type LOX/kerosene (with LOX/LH2 upper stages) vehicle (whose first stage could be reusable like the Falcons’), or for a reusable winged autonomously-flown (and LOX/kerosene-powered), turbofan-equipped flyback booster (like the B8D or B8G winged booster design of the General Dynamics Phase B Space Shuttle designs, see: http://www.pmview.com/spaceodysseytwo/spacelvs/sld029.htm ). Such a “universal” booster could carry expendable upper stages, or a plug nozzle-equipped reusable vertical landing second stage (similar to Philip Bono’s SSTO designs that he proposed at McDonnell Douglas, but less challenging to develop since it wouldn’t be SSTO), or a low cross-range, straight-winged orbiter like the B8 boosters’ “NAR-130” orbiter (see: http://www.pmview.com/spaceodysseytwo/spacelvs/sld029.htm ), but with a more modest payload so that it could be smaller and easier to develop. This orbiter–like the turbofan-equipped “NAR-130” orbiter–would be a space-adapted airplane rather than a glide-recovered re-entry vehicle, and unlike the delta-winged Shuttle orbiter, it could ferry itself and make missed landing approaches (a “luxury” our Shuttle didn’t have; that lack was crazy for an “operational” vehicle) instead of having to be carried around atop a 747, and:

              I think something like the old ESSA (Environmental Science Services Administration) would be more than adequate for our needs; if the Europeans want to keep running around like a chicken with its head cut off about “The End is Near!”, I’d be happy to let them bang that drum. As well:

              Having talked with people in the weather field, plus having read and observed on my own, I’m not particularly troubled over “the rage of our age” (in the 1970s, ice ages were “in fashion,” and we were all going to freeze to death). The real remedy to prevent future problems (including shortages) is to curb our numbers, and that happens as a matter of course as more women are empowered, more people become better educated and more affluent, and infant mortality rates go down; they have fewer children. This is already beginning to happen, and I chuckle at those who fear the coming population decline (I’ve already seen some experts lamenting it on TV), because it’s exactly what we need. The alternative is sheer madness, as unending population growth (even if it’s slow) is a hallmark of…cancer. Humanity must–and can–do better than that.

            • Alexander Tolley June 15, 2017, 12:05

              Unfortunately, the EU is not able to take up the slack. maybe they will in future. NOAA doesn’t have the space capabilities either, even though Earth monitoring is being shifted to that agency.

              It may well be that SpaceX, Blue Origin and others may be able to replace the SLS, although mission payloads would have to be redesigned as neither have a rocket even nearly ready to go that will have the SLS lift capability. What they will have is better (much better) launch frequency for smaller payloads. Only SpaceX’ ideas for their ITS would exceed the SLS lift capability. My guess is that FH will be ready long before the SLS, even if they have early setbacks. Maybe BO will have a similar capability ready in a few years too. We’ll see. Competition is good.

  • ljk July 14, 2017, 9:45


    The Search for Extraterrestrial Artifacts

    SETI research is picking up on the other side of the Atlantic.

    By Dirk Schulze-Makuch


    July 13, 2017 3:30 PM

    The first workshop of the new German SETI initiative recently convened in the southern town of Freiburg, with experts in fields ranging from social science to satellite imaging on hand to discuss how to advance the search for extraterrestrial intelligent life.

    Michael Schetsche from the University of Freiburg started things off with a talk on the possible consequences of first contact with an extraterrestrial species, and how we might prepare for such an encounter.

    A symposium held at the Library of Congress in Washington D.C. three years ago had a similar theme, but Schetsche’s talk focused more on contact with artificial intelligence or machine-based life.

    Other talks had to do with SETA, the search for extraterrestrial artifacts, which will be one subject of future research by the German research network. Hakan Kayal from the University of Würzburg outlined today’s technical state of the art in detecting and identifying objects in space, whether natural phenomena such as meteorites and sprites, or presumed extraterrestrial probes. It was sobering that even in Earth’s vicinity we could only detect very large (kilometer-size!) probes, or those that had a huge energy output.

    Other experts in the research network are addressing questions of possible cultural exchange and communication between a putative extraterrestrial civilization and humans. Advanced alien civilizations might use probes to engage in interstellar communication or observe other planets such as Earth. This intriguing idea led Robert Freitas and Francisco Valdes in the 1970s to conduct a photographic search of the Earth-Moon Lagrange points, where a probe could be “parked” without any energy expenditure. They did not find anything, down to a detection limit of about 14th magnitude. But that was 40 years ago, and with today’s technology a more thorough search could be conducted of the Lagrange points and other localities.

    Funding for this type of research is hard to come by, however, and is more likely to come from private sponsors rather than traditional government sources—a possibility the German research network is looking into.

    After many years where SETI was pursued almost solely in the United States—primarily by the SETI Institute—Germany is finally stepping up to join in the search, as are other countries in Europe, including France. That means we can look forward to significant contributions from scientists on both sides of the Atlantic in the near future.

  • ljk July 18, 2017, 12:56

    What would it take to wipe out life on Earth cosmically speaking and what can we learn from this regarding other worlds and their potential life?

    The Resilience of Life to Astrophysical Events