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SETI: The Pollution Factor

We tend to assume that our mistakes as a species flag us as immature, a young civilization blundering about with tools it is misusing on a course that may lead to extinction. But assume for a moment that an intelligent extraterrestrial civilization goes through phases more or less like our own. If we’re sifting through radio signals and looking for optical flashes to find them, shouldn’t we consider other ways such a civilization announces itself? What if we’re not the only polluters in the universe, for example, and other cultures are making the same mistakes?

In a 2010 paper, Jean Schneider (Observatoire de Paris-Meudon) and colleagues noted the possibility of using pollutants as a way of moving beyond biosignatures to find ETI. Let me quote from the paper:

…another type of far from equilibrium signals can be seen as techno-signatures, i.e., spectral features not explained by complex organic chemistry, like laser emissions. In the present state of our knowledge one cannot eliminate them a priori, although we have no guiding lines to search for them. For instance, in the present Earth atmosphere, CFC (Carbon Fluoro Compounds) gases are the result of technological chemical synthesis. Observed over interstellar distances, they would reveal to the observer the presence of a technology on our planet.

Lisa Kaltenegger (Harvard-Smithsonian Center for Astrophysics) and James Kasting (Pennsylvania State) have been looking at the CFC idea for some time. As Kasting told New Scientist in 2009, “There’s a whole host of things we make industrially as solvents, cleaners and refrigerants – they certainly have absorption lines. If you had a big enough telescope, you could detect them.” CFCs themselves absorb infrared light at specific wavelengths and are detectable at very low concentrations, as low as a few parts in a trillion. Moreover, they do not form naturally, and though a detection would be tricky, Kaltenegger has suggested a future array of space telescopes working at infrared wavelengths should be able to do the job. For more on this, see To Spot an Alien, Follow the Pollution Trail, the original article in New Scientist.


Image credit: CfA.

But would it take such a futuristic flotilla of telescopes to spot pollution? New work out of the Harvard-Smithsonian Center for Astrophysics suggests even the James Webb Space Telescope may be up to the challenge. The paper argues that atmospheric levels of CFCs about ten times greater than we have produced here on Earth could be traced by JWST. The focus here is on tetrafluoromethane (CF4) and trichlorofluoromethane (CCl3F), described as the easiest CFCs to detect. Henry Lin and team point out that the lifetimes of CFCs range from 10 to 105 years, meaning that a polluting civilization existing any time in the past 105 years would be theoretically detectable.

But the strategy only works in detecting pollutants on Earth-like planets circling a white dwarf star, a scenario that maximizes the atmospheric signal. Recent work has shown that white dwarfs can have long-lived habitable zones, and the similarity in size between the planet and star offers the best contrast between the planet’s atmospheric transmission spectrum and the star it is transiting. The paper considers white dwarfs that have cooled to surface temperatures around 6000 K, the same surface temperature as the Sun, so that the habitable zone is close in, at about 0.01 AU, which greatly increases the chance of a transit.

From the paper:

…a recent study by Worton et al. (2007) estimates the atmospheric concentration of CF4 at ~75 parts per trillion (ppt), whereas CF4 levels were at ~40 ppt around ~1950. Assuming a constant production rate…we expect as a very crude estimate that in roughly ~1000 years, the concentration of CF4 will reach 10 times its present levels. Coupled with the fact that the half-life of CF4 in the atmosphere is ~50,000 years, it is not inconceivable that an alien civilization which industrialized many millennia ago might have detectable levels of CF4. A more optimistic possibility is that the alien civilization is deliberately emitting molecules with high GWP [global warming potential] to terraform a planet on the outer edge of the habitable zone, or to keep their planet warm as the white dwarf slowly cools.

The JWST should be able to detect CF4 and CCl3F signatures in the atmospheres of transiting Earths around white dwarfs as long as their concentrations are on the order of ten times that of the Earth — CF4 detection demands 1.7 days of exposure time on the instrument and CCl3F 1.2 days. The exposure time is already built into biosignature study times, given that these will take on the order of an entire day to detect. Looking for pollutants, then, adds little in terms of additional observing costs.

Bear in mind that while some CFCs last for tens of thousands of years in the atmosphere, others persist no more than ten. Harvard’s Avi Loeb, one of the trio of researchers in this project, points out that finding a short-lived CFC on an exoplanet would signal an active civilization. The other scenario may be starker. If we detect molecules from long-lived CFCs but none of the short-lived variety, we could be witnessing a changing civilization. “In that case,” says Loeb, “we could speculate that the aliens wised up and cleaned up their act. Or in a darker scenario, it would serve as a warning sign of the dangers of not being good stewards of our own planet.”

The paper is Lin et al., “Detecting Industrial Pollution in the Atmospheres of Earth-like Exoplanets,” accepted by The Astrophysical Journal and available as a preprint. The Jean Schneider paper is “The Far Future of Exoplanet Direct Characterization,” Astrobiology 10 (2010), p. 121.


Comments on this entry are closed.

  • ljk July 24, 2014, 12:48

    7/23/2014 @ 9:29 PM

    Alien Artifacts On The Moon?

    By Bruce Dorminey

    As nutty as it may seem to the uninitiated, the notion of looking for alien artifacts on our own Moon may finally be gaining mainstream scientific traction.

    There are good reasons to seriously consider the possibility that at some point in the Earth-Moon system’s storied 4.5 billion year-old history, an alien intelligence may have passed through our solar system; leaving physical artifacts of their visits.

    These artifacts would likely entail more than just alien space trash, and would arguably include evidence of alien scientific or industrial activity, such as extremely advanced lunar mining, energy generation; even technology related to lunar nearside Earth reconnaissance.

    Or so says Paul Davies, a longtime SETI (Search for Extraterrestrial Intelligence) researcher, physicist, and now Director of the Beyond Center at Arizona State University in Tempe.

    Full article here:


    To quote:

    At least one related paper on the subject is due to presented at the September meeting of the UK SETI Research Network, a group of mainstream British academicians. But even a decade ago, talk of alien lunar artifacts was mostly beyond the ken of anything remotely resembling the mainstream astronomical community.

    With the success of crowdsourcing, citizen science initiatives such as SETI@home; Einstein@home; and Cosmology@home however, Davies and a handful of other serious scientific researchers are now advocating marrying crowdsourcing analysis with the images now being catalogued by NASA’s Lunar Reconnaissance Orbiter (LRO).

    Since 2009, LRO has been measuring lunar landforms down to half meter resolution; in the process targeting more than 10,000 lunar sites and covering up to 90 percent of the lunar surface. The mission’s current success has resulted in a treasure trove of thousands of very high resolution images, almost all of which could be searched via an citizen science initiative.

    Davies thinks the ideal lunar survey would not only include a search for optical anomalies but would go beyond the breadth of LRO’s own mission to include searches for evidence of alien lunar industrial activity.

    “[Evidence of past] mining or quarrying could show up in gravimetry or magnetic surveys, even if an ancient mine was buried under the lunar regolith,” said Davies. “We could detect [alien] nuclear waste perhaps from a lunar satellite by looking for localized gamma ray sources from the lunar surface.”


    “Professional astronomers sometimes suffer from the tendency to discount anything other than our expected signal as instrumental noise or some kind of interference,” said Siemion. “When identifying the unexpected, the eye of an amateur citizen scientist can be just as effective, if not more so, than that of a conditioned professional.”

    Amen, brother.

  • ljk July 24, 2014, 15:46

    Speaking of detecting pollution as a way to find ETI, here is a Centauri Dreams article from late 2011 on how we might be able to detect an alien society’s light pollution – assuming they don’t care enough to want to see celestial objects from their surface of their world:


    Here is a Centauri Dreams article also from 2011 on how the debris from mining planetoids might be used as an indicator of intelligent technological activity:


    Some more related CD articles next. The first one is the recent piece on glimpsing heat from alien technologies:









  • ljk July 24, 2014, 16:02

    How ironic if our efforts to make Earth a cleaner place make us less detectable to alien devices. Of course this might be a good thing encountering some ETI would be a negative event, but we may also be missing out on joining the Galactic Club or its equivalent.

    Of course a cleaner planet will mean more plants and animals, so we should remain detectable to those who are seeking others in the galaxy via biosignatures.

    If we decide to dump our trash and other toxic materials into Sol to remove it permanently from Earth, ETI might notice signatures in our sun’s spectrum not natural for a yellow dwarf star. Read more on this in the section titled “Optical (Visible) Radiation” in this paper online here:


  • ljk July 24, 2014, 16:06

    Speaking of pollution, there is the theory that life on Earth came about when an alien expedition stopped by our planet in its very early days (after it cooled, we presume) and left behind some of their trash, from which all life on this planet evolved.

    Hey, we left a lot of stuff from all those Apollo missions on the Moon. And who remembers the Mars rover Opportunity investigating the debris scattered about from its discarded heat shield. Yes presumably all these items were sterilized, but no method is perfect and we made a mess with every landing on every world we have ever visited so far. Such things may be unavoidable.

  • Geoffrey Hillend July 24, 2014, 16:17

    I like the idea of detecting CFC’s and pollution in the atmosphere of an ET planet. Civilizations which are more than one thousand years more advanced than us might not have any since they changed to green technology and cleaned up their planet long ago.

    The idea of livable planets around white dwarf stars is interesting. I guess it would have to be pretty close to the star to be in it’s life belt. How can an Earth like planet exist around a white dwarf when it had to survive the heat of the red giant phase?

  • d.m.falk July 24, 2014, 16:59

    Sometime last year, I was trying to point out this very thing, that it might be possible to detect absorption lines corresponding to artificial development, consistent with burning, smelting, carbide and hydrocarbon usage, ozone levels, and so forth, while at the same time seeing the telltale infrared signatures of organic life, as well as polarised light from water. We would even be able to tell what stage of development, simply by these signs. And yes, even if we “clean up” our own planet, there will be telltale signatures both of longterm effects from our then-previous pollution levels, and of the near-artificial state of “cleanliness”, that will still show signs of artificial development and a possible removal of nature’s own kind of pollution. Yes, we could make it “too pristine” to be natural– And this would also be detectable from and by ETI. Add this to being able to tell rotation periods, land/water/organic life distribution, even the weather, all from the light curve of a single pixel, it’s a fair bet we’ll be able to know quite a lot about terrestrial-type planets within a decade. Even if we don’t have contact now, what will be happening soon will be the single biggest change in our conscious understanding of our place in the universe- We will no longer be dreaming, we will know! This is indeed the most exciting time in the history of space sciences! Yes! Look for the light curves! Look for the absorption and reflection lines! We will learn! :)


  • Joëlle B. July 24, 2014, 23:42

    Interesting to note that when our star ultimately cools to it’s white dwarf stage, the inner planets (this includes the Earth) will have been long gone if nothing is done to modify their orbits, stabilize the star, or some other method of action is taken–this being the final (and longest lasting) stage of the star’s progenitorial state. So it might be a good idea to start leaving some sort of long lasting bio/techno signatures on the outer solar system, for a ‘just in case’ scenario to signal ‘we were/are here’.

    Also, there doesn’t appear to be very many confirmed exoplanets discovered, as of yet to reference, orbiting systems with white dwarfs. A nice find of intriguing white dwarf activity around the KOI-256 red dwarf system found in the below links may indicate further investigation (maybe of possible ETI activity?) being necessary:

    Popular description: http://news.discovery.com/space/alien-life-exoplanets/kepler-watches-white-dwarfs-gravity-warp-spacetime-13040.htm

    NASA press release and video: http://www.nasa.gov/mission_pages/kepler/news/kepler20130404.html


    Article: http://arxiv.org/abs/1304.1165

    Also, another binary system worth taking a look at (see the Related Publications section for more details): http://exoplanet.eu/catalog/nn_ser_%28ab%29_c/

    A question that comes to mind; will the outer planets (of our Sol system) warm and become complimentary to life or will second generation planet formation cause currently unknown results? And also, do the same rules apply to binary/multiple systems as opposed to single post-giants?

  • Joëlle B. July 25, 2014, 1:41

    Found in further reading,

    ‘Main-sequence progenitor configurations of the NN Ser candidate circumbinary planetary system are dynamically unstable’


  • Ron S July 25, 2014, 10:03

    I suppose a sign of truly intelligent life would not be the presence of pollutants in their planet’s atmosphere, but rather the absence of pollutants. Unlike us.

    Paul, this is not the first time Avi Loeb’s name has come up in regards to passive, modest budget ETI searches piggybacking on other science instruments and experiments (e.g. LOFAR from a few years ago). It might be interesting to hear from him on his thoughts and further ideas on the general topic since it is one he seems passionate about.

  • Joëlle B. July 25, 2014, 10:50

    For starters, maybe just staying alive will serve as a good biosignature to leave for potential ETI to discover, while at the same time keeping a technological signature within that biosignature. This article goes into nice detail of the possibilities, focused on Panspermia, ethics and propagating the genetic code as a carrier for interstellar messages: http://arxiv.org/ftp/arxiv/papers/1407/1407.5618.pdf

    One thing that specifically caught my attention in the paper was:

    “Another advantage of the “genetic METI” over external artifacts is that it guarantees that the message will be discovered no sooner than the recipient becomes capable of cracking the genetic code, i.e. achieves scientifically advanced stage. That precludes interference with the pre-scientific cultural evolution […]” (Makukov, shCherbak 2014)

    Sounds a lot like how in Star Trek first contact would not be made with a civilization until it was able to leave a warp drive signature or was able to utilize some other form of interstellar capability.


    Another highlight from the paper was the idea of only seeding newly formed worlds to reduce the risk of invading an already present ecosystem:

    ” The necessary requirement therefore for the target exoplanets is that they must not reveal any kind of biosignatures. As this requirement is obviously insufficient, the most straightforward way to further minimize the risk of interfering with indigenous life is to select newborn exoplanets or even planetary systems still at the stage of formation. However, as the majority of stars are formed in a clustered mode, the most efficient strategy proves to be in seeding collapsing clouds that form open star clusters. Not only that minimizes the risk of interfering, but natural panspermia within clusters (which is far more likely than natural transfer of viable cells between field stars) and within infant planetary systems might greatly amplify the result. Many seeded planets are then dispersed throughout the Galaxy with their host stars as clusters quickly dissolve in the galactic disc within few millions of years after formation. Besides, seeding star-forming clouds does not require sophisticated technologies for extremely precise navigation needed to seed individual exoplanets.” (Makukov, shCherbak 2014)

  • Alex Tolley July 25, 2014, 11:56

    I would have thought CFC’s are likely to be am Earth centric pollutant. Had we not been so careless, there might be very little sign of them today as non-polluting substitutes would have been used earlier.

    Given a demand for energy in an economy, I would have thought that possibly a unexpected heat signature of a planet might be more detectable, especially if it indicates that more IR is emitted than could be accounted for by solar radiation (although vulcanism might make interpretation ambiguous).

    Despite the claim of CFC atmospheric longevity,if an advanced species was trying to be unobserved by a potentially hostile galaxy, I would have thought they would have tried to make their planet as inconspicuous as possible by removing such traces, even at high cost.

    @ljk – I do like the idea of looking for artifacts of previous activity in our solar system. This seems to play into the hands of swarms of micro sensors providing much more comprehensive surveys of our solar system, at low cost. Looking at the moon in detail with many eyes (and even software) seems like a worthwhile idea, although it wouldn’t detect TMA-1 (but it would detect the original Sentinel). A good test would be confirmation of finding all our artifacts, although I doubt Al Shepard’s golf balls would be detectable. Paul Davies has also suggested looking for “shadow life” on Earth – a provocative idea that might be very hard to detect unless we have some idea how to do this.

  • david lewis July 25, 2014, 12:35

    Should we ever try to terraform Mars then we would probably use large amounts of such CFCs. So long as humans in some form remained on the planet then it would be a strong signal that some ET could observe. Rather than just 100,000 years it could be a signal that last for a billion years or more.

    Also, if ETs are into colonization, using such chemicals to warm a world that’s just a little too cold might be easier than cooling one that’s too warm. Once again it means we’re no longer limited to the 100,000 year limit, but rather one that might be in the millions, or even the billions. Nor would it be just one world per ET species, but any number of them.

  • Gerry July 25, 2014, 14:09

    In response to the comments about surveying the Moon, wasn’t part of the premise of “2001” that the Monolith Builders left their artifact on the Moon specifically because they didn’t want humanity to come across it until they had achieved a certain level of sophistication?

    Also, while the Lin paper discusses white dwarf planets as targets, which is probably unlikely to actually pan out, it is a good proof of the concept of detecting atmospheric signatures of technological life, which I assume will be more widely applicable to other more likely star systems as technology and methods improve.

  • ljk July 25, 2014, 16:30

    Gerry said on July 25, 2014 at 14:09:

    “In response to the comments about surveying the Moon, wasn’t part of the premise of “2001″ that the Monolith Builders left their artifact on the Moon specifically because they didn’t want humanity to come across it until they had achieved a certain level of sophistication?”

    That is correct. The ETI deliberately buried the Monolith on the Moon so that the humans could only discover it after they had achieved a level which made such things possible.

    Of course one can ask if being technologically advanced also equals a similar high level of ethics and morality. I know this is fictional, but the Borg from Star Trek thought they were uplifting other species by making them into Borgs – which most of the other species tended to disagree with regarding such ideals.

    Then Gerry said:

    “Also, while the Lin paper discusses white dwarf planets as targets, which is probably unlikely to actually pan out, it is a good proof of the concept of detecting atmospheric signatures of technological life, which I assume will be more widely applicable to other more likely star systems as technology and methods improve.”

    While it is probable that not much in terms of living would be in a white dwarf system if we are referring to native beings, there could be visitors from other star systems conducting science or mining operations, among other possibilities we may not even be able to imagine at this time.

  • Geoffrey Hillend July 25, 2014, 17:25

    @Alex Tolley I like your idea of the infra red signature. We could compare it with Earths. The difference between Co2 produced by volcanoes and man made Co2 from Coal burning etc is not ambiguous. Geo-chemists noticed by examining tree rings that man made Co2 is higher in the C12 isotope than Co2 produced by volcanoes which is higher in C13. We could see that difference with a telescope and spectroscopy from the light of an ET planet provided their planetary evolution was similar to our own. Also carbon monoxide.


  • Eniac July 25, 2014, 22:20

    david lewis:

    Nor would it be just one world per ET species, but any number of them.

    Exactly. And, in time, all of them. Including our own. Only, we wouldn’t be here, alone on our world, if that had happened, would we now?

  • d.m.falk July 25, 2014, 23:10

    Something I should add, and it’s something involving a particular hobby of mine, and this happens to be the subject of infrared detection of exoplanets. I’m an infrared photographer, so I encounter this quite a bit. So what’s the problem? Well, we’re talking about finding organic signatures in the infrared, but in this case, it’s optical, or near-infrared, about 700-3000nm in wavelength. (Digital cameras, with filters removed, can “see” out to 1200nm. Red ends about 700nm.) This doesn’t include thermal infrared (10,000n-30,000nm+!), which many assume is being discussed when talking about infrared. It’s in the near-infrared range that the James Webb telescope will excel in, and with that, our greatest hope in finding exoplanets with possible life.


  • Geoffrey Hillend July 26, 2014, 22:58

    @d.m.falk If you want to get technical, the near infra-red is from 750 to 1400 nanometers or .75 um(microns) to 1.4 um. The short wavelength infra-red is from 1400 nanometers to 3000. The mid infrared is from 3000 to 8000 nanometers, the long wavelength infra red is from 8000, 15,000 nanometers and the far infra red is 15 um to 1000 um.

    The gases that represent a signature for life like oxygen absorbs at 750 nm, Co2, 2000 nm, H20 2500 nm fall between the near and the short wavelength infra-red that is between 750 and 3000. The mid through the far are sometimes known as the thermal infra-red. http://en.wikipedia.org/wiki/Greenhouse_effect

    Some web sites don’t make such exact distinctions but you want to be careful what you call thermal radiation because black body radiation in the “thermal infra red” as we say here are usually hot bodies like stars and not planets depending on how precise you make these categories.

    Every gas absorbs light at a specific frequency due to that quantum nature of atoms; Each element has a different atomic number because is has different electrons in their shells and therefore different energy level. Co2 absorbs light at a very specific frequency such as the minus -667 centimeter frequency at the most amount of black body infra-red radiation leaving the ground or Earth. My point is that when Co2 absorbs an infra-red light photon it vibrates and rotates that atom which re-emits the light photon at the same frequency in a random direction. The same photon is re-absorbed by another Co2 molecule and re-emitted randomly. This process traps heat in the air and slows it down from escaping into space. Source Beyond UFO’s, Bennet. This is still thermal energy since the rotation and vibration of a molecule and an atom is thermal energy. All other light passes through it but not short wavelength infra-red.

    We can only identify Co2 based on the fact that it absorbs light at a specific frequency which show up as black lines on the color bands of a defraction grating or spectroscope through a telescope. The spectroscope splits light into colors like a prism.

  • Geoffrey Hillend July 26, 2014, 23:01

    Every atom absorbs light at a different frequency. Absolutely Small. Fayer.

  • Geoffrey Hillend July 26, 2014, 23:17

    An of course most of the infra red heat radiation that is re-radiated from the ground after is it heated by the Sun is in the the short wavelength infra-red, near the minus -667 centimeter frequency. Ibid. p. 305.

  • Geoffrey Hillend July 26, 2014, 23:48

    Excuse, me what the frequency range they call thermal infrared is not bodies as hot as stars.

  • Joëlle B. July 27, 2014, 1:48

    ljk said on July 25, 2014 at 16:30

    “Of course one can ask if being technologically advanced also equals a similar high level of ethics and morality. I know this is fictional, but the Borg from Star Trek thought they were uplifting other species by making them into Borgs – which most of the other species tended to disagree with regarding such ideals.”

    Good point.

    And the attitude of the Borg directly contrasts the views of the Vulcans, who helped humanity develop Warp 5 technology, without forcibly assimilating their own methodologies. This, in turn, allowed for the humans to invent their own unique (and more viable) solution to the flux paradox, surpassing even Vulcan ingenuity. I guess a more relatable, real-life example would be something along the lines of ‘self-determination theory’. However, assuming that the diverse forms of extraterrestrial intelligence can exist in the “real” universe (i.e. real ‘alien’, non-DNA life, which the Vulcan’s and Humans did not represent [ both were descendants of a common ancestor, see http://en.memory-alpha.org/wiki/Ancient_humanoid ], one may tend to find themselves out of the realm of science and more in the realm of philosophy (especially when debating the issue of “ethics”).

    Of course, the Vulcans were not guiltless, in that they had their own ethical prejudices toward human progress, as seen in the ‘First Flight’ episode of Enterprise, when they suggested that humans were progressing too quickly and needed to restart their warp technologies from scratch, due to a mistake made during a warp simulation ending in the destruction of the ship, NX-Alpha. http://en.memory-alpha.org/wiki/NX-Alpha

    So, I suppose that what we deem ethically sound can directly be correlated with our technological prowess (and also be very telling of the way we approach technological problems), though we must consider the probable realities of other lifeforms’ own ethical history and even psychological underpinnings. Our views have also been limited by only having one space-faring, technological civilization to study (our own). Nonetheless, I think I am adequately craved to go re-watch Star Trek, now. :D

    The pollutant signs of planetary systems may also be ethical indicators of what stage a civilization may be at, as many above posters have assessed. Maybe if there are advanced ETI out there, they would rather want to come into contact with a species not on the verge of destroying its own ecosystem (sans humans); the first premise being astrobiologically ethical: if they develop -purposeful- self-destructive tendencies, we leave them alone to allow them their own self-determination to that destruction/extinction–the second premise being morally ethical: if we save them from self destruction, would we have introduced an exterminating species into a foreign way of life, invasive to their biological fate… Which is a scary thought, considering what type of stellar system we live in comparatively to other, more longer lived systems (if we posit that beings exist in such systems [or independent of them] with a set of beliefs or ethics).


  • Geoffrey Hillend July 27, 2014, 16:35

    Stanton Friedman, a physicist who is advocates the belief in UFO’s thought we are too violent, primitive and warlike for advanced ET’s to want to contact us so this is not a new idea. I like the idea. It’s a hypothesis that could potentially explain the Fermi paradox.
    If it’s true, then we are on our own. They won’t interfere due to the “prime directive. ” There may indeed be certain stages of the development of a civilization that may be self destructive but they may be limited to the general level of collective consciousness which continually evolves and a specific time period early in it’s evolution. We have to assume we will evolve beyond it at other ET civilizations have also. It’s ethical and necessary to be positive about it. It forces one to think beyond oneself and the future of humanity. We are all in it together at the end of the day. One could assume everything will be extinct in the future or we will have more freedom and incredible technology.

  • Geoffrey Hillend July 27, 2014, 16:48

    I don’t see how Wikipedia, the Greenhouse effect page Solar radiation spectrum comes up with 2000 nanometers for Co2 absorption at ground level. http://en.wikipedia.org/wiki/Greenhouse_effect Many sources say that Co2 absorbs at the -667 centimeter frequency, which is one 667th a centimeter or 667 cycles a centimeter, so one cycle converts into about 14 micrometers or 14000 nanometers which is in the longwave infra-red from 8-15 micrometers.

    Maybe that absorption is not taken exactly at ground level and it depends on the height of the atmosphere that absorption takes place? I am not an expert in spectroscopy so maybe Wikipedia is wrong?

  • Triffin July 29, 2014, 13:02

    “There are good reasons to seriously consider the possibility that at some point in the Earth-Moon system’s storied 4.5 billion year-old history, an alien intelligence may have passed through our solar system; leaving physical artifacts of their visits.”

    Could not human DNA be the “physical artifacts of their visits” ??
    Perhaps we’ve merely forgotten who we are and where we came from ..

    Triff ..

  • ljk July 29, 2014, 16:59

    Mysterious fast radio bursts from outer space: Astronomers baffled, admit they could be alien in origin

    By Sebastian Anthony on July 29, 2014 at 8:36 am

    Since 2001, the Parkes radio telescope in Australia has been picking up mysterious, unidentified bursts of energy that astronomers have since dubbed “fast radio bursts.” At first, because no other telescope in the world had ever seen these bursts, it was assumed that these FRBs were probably just glitches in the telescope’s electronics — but now, 13 years later, a telescope on the other side of the planet in Puerto Rico has detected an FRB. This second FRB detection means that it isn’t just a fluke — and more importantly, that astronomers have absolutely no idea what’s causing them.

    Some theories have suggested that FRBs originate from an evaporating black hole, or perhaps solar flares from nearby stars, or — and this is coming from one of the astronomers who first recorded the FRBs — they could even be “signatures from extraterrestrial civilizations.”

    The first FRB was discovered by chance in 2007, when a team of astrophysicists led by Duncan Lorimer was poring through old archival data from the Parkes Observatory in New South Wales, Australia (pictured top).

    On the night of August 24, 2001, a five-millisecond burst of radio waves erupted from an otherwise calm patch of night sky near the Small Magellanic Cloud and hit the telescope. Lorimer and co analyzed the single burst for years, but without any additional data from further bursts it was impossible to say if it was actually a new astrophysical phenomenon — or just a man-made or local source of interference, such as an electronics glitch or lightning storm. Finally, in 2013, another team finally got the go-ahead to analyze a full year’s worth of data from the Parkes telescope — and sure enough, they found four more similar bursts.

    Full article here:


    To quote:

    Or, of course, the other possibility is that FRBs are produced by some kind of intergalactic extraterrestrial civilization. Speaking to NPR, Duncan Lorimer says with a little bit of chagrin that “there’s even been discussions [about FRBs] in [research papers] about signatures from extraterrestrial civilizations.”

    Lorimer is referring to a single research paper that explores the possibility of the bursts being intentionally created by an alien civilization to broadcast their existence to the rest of the universe. This is just a theory, of course, but really, we know so little about FRBs that just about any theory is worth investigating at this point.

  • Geoffrey Hillend July 29, 2014, 17:25

    I think the answer to that is no. The DNA has 3.1 billion base pairs and the ability to mutate and create many life forms. We did not need any aliens to give us DNA. All life began in the sea. There was a time in the early universe say the first billion or two years when there was no life and not any planets around stars. The proof is that the oldest stars are metal poor as seen through telescopic spectroscopy because the heavy elements to make planets and people had not yet been fused together in the nuclear furnaces of stars and supernova explosions.

    Consequently, the first ET we assume evolved before us did not have any aliens to alter or add their DNA, they had to evolve out of the sea since their was no one around before them to give them DNA.

    Bone morphology shows we evolved from hominids. The cerebral cortex or brain size increases through millions of years.

  • Geoffrey Hillend July 29, 2014, 17:31

    and the sea they had to evolve out was on another planet

  • ljk July 30, 2014, 11:16


    NASA Could Use SETI’s New Funding Model for Future NASA Projects

    Added by Adrianne Hill on July 29, 2014

    NASA could use a new funding model from Search for Extraterrestrial Intelligence (SETI) for future projects. Astrobiologist Jacob Haqq-Misra came up with an idea that would help the struggling organization by introducing a lottery bond, which gets investors to buy bonds at a certain price, and receive a guaranteed rate of return while SETI continues its research and observation for extraterrestrial life. When the first sign of life is received, all investors receive their initial investments, and there will be certain investors that are chosen by random to win a monetary prize.

    SETI is strapped for cash at the moment, and its director Jill Tarter, the model for Jodie Foster’s character Ellie Arroway in the 1997 movie Contact, has stepped down as director of the organization to devote herself to obtaining funding. She has given talks to potential investors and so far it has been a long, frustrating journey for her. Haqq-Misra’s idea gave Tarter hope for a model that would provide stable and reliable yearly funding so SETI’s budget can be properly and uniformly utilized.

    There is a lot of skepticism about this project, with fellow scientists understanding that investors would have to be specifically interested in funding this project with no guaranteed rate of return. But there has to be a new funding model, and SETI’s dire need for cash is a driving force for new ideas of funding and investment, which could also be used for funding future NASA projects.

    SETI has been struggling with funding for years since its funding from NASA was cut by the government in 1993. Although the initial legislation cut SETI from the budget for only a year, NASA’s budget became so tight that SETI fell by the wayside. Charitable donations have sustained the organization ever since.

    In April of 2011, the situation got so bad that SETI had to walk away from the heart of its research, the radio telescope array. The array monitors the skies, searching faithfully for radio signals that could lead to the discovery of life on other worlds. After its appeal to the public, SETI met and exceeded its goal of $200,000, reviving its research and watchful ear to the skies. They also built the Allen Telescope Array, which was funded in part by Microsoft co-founder Paul Allen, and they named the array in his honor in 2007. The array’s yearly costs are $1.5 million dollars.

    Haqq-Misra is talking with economists and scientists as well as SETI researchers. He remains optimistic, because no one has told him it is not possible so far. He would like to use bank bonds, and sees banks as a feasible way to manage large amounts of money as well as cushioning the blow of initial losses.

    More recently, a startup company named Uwingu, Swahili for “sky,” is aiming to bridge the gap between cash-strapped space research projects and their funding. Governmental budgets are shrinking dramatically in the areas of science and technology. NASA is also a victim of those budget cuts, and it can only be imagined what could be achieved if there was a stable and reliable source of income for these programs.

    The defense and aeronautical industries are flush with cash, due to their profiting off of the U.S. government’s past and future defense budgets, and it would be a good investment and a way to balance these budgets without congressional approval. In any case, a new project funding model is needed, that could be used not just for SETI’s future, but NASA’s as well.

    By Adrianne Hill

  • ljk July 31, 2014, 9:53


    Harvard’s starry-eyed wonder

    By Thomas Farragher | GLOBE COLUMNIST JULY 30, 2014

    It sits atop a pine-studded hill, 25 miles west and far from the bright lights of Boston, tucked into a stand of tall trees beyond the horse farms and the apple orchards of north Worcester County.

    Each night when the skies are clear, a 4-ton retractable roof on an otherwise nondescript wooden structure rolls away, and machinery inside whirs to life to renew its methodical search for what would be the most stunning discovery since the dawn of man.

    With a 72-inch optical telescope, Harvard University scientists are searching for signals from advanced and distant civilizations, each second processing a quantity of data equal to the text of all books now in print.

    Are we alone? Fat chance, they say.

    “They can’t be dumber than we are because if they are dumber, they wouldn’t be able to send us signals,’’ Paul Horowitz, a Harvard research professor of physics, told me in his office just off Harvard Yard. “If we make contact with anybody, they’re going to blow us away with their smartitude.’’

    Horowitz is an energetic, impish, self-deprecating man who dashes around his third-floor office, pulling books from shelves that stretch to a high ceiling or scooting over to computer monitors to dole out morsels of celestial knowledge.

    While he insists that he’s a “boring nerd,’’ the guy has got to be the most popular cocktail party guest in his ZIP code. Maybe his time zone.

    Did you know that there are more stars in the universe than grains of sand on all the beaches? And there are tens of billions of Earth-like planets in our galaxy alone?

    Horowitz is a pioneer in the search for extraterrestrial intelligence. His work has drawn plaudits and snickers, and he’s keenly aware of both.

    There are nonbelievers everywhere. But Horowitz has been working to prove then wrong almost since his grad school roommate took a course taught by legendary astronomer Carl Sagan, with whom Horowitz would later work.

    [Aliens are NOT a belief system! Does the Boston Globe not have any science writers with actual science knowledge left?” – LJK]

    “We’re all hoping someone makes the discovery before we all croak,’’ he said. “That’s what keeps me going, I suppose.’’

    The optical telescope on the hill at the Oak Ridge Observatory in Harvard is seeking laser signals from other worlds, making a trillion measurements of the heavens every second. Horowitz used to search for radio transmissions, but switched for surprisingly easy-to-understand reasons: “We got tired of radio transmissions because we weren’t finding anything.’’

    There were moments of pulse-racing possible discoveries, but nothing that survived scrutiny. In other words, no contact.

    Horowitz has allowed himself to imagine what would happen when that day arrives. And he has allowed himself to think what the real ET might look like. Not like us. Maybe silicon, a post-biological being. Not upright, bipedal hominoids. “Get rid of your biological chauvinism,’’ he said. “Stop thinking about it that way. There’s no reason to believe they’ll look like us.’’

    For now, he watches and waits.

    “Someone once told me that I’ve got one chance in a million to become the most famous person ever,’’ the professor said. “Maybe it’s a little less. But it’s guaranteed to be the most famous discovery ever.’’

    Who hasn’t imagined that?

    When I was a kid in the early 1960s, my dad would pile us all into the back of our battered station wagon and we’d head for a long-gone drive-in. The most memorable movie of those summer screenings was the 1951 classic, “The Day the Earth Stood Still,’’ starring Michael Rennie as the alien.

    There is a signature line from that movie that my brother and I still toss at each other from time to time for no reason at all. And I wanted to use it with Horowitz.

    I struggled to figure out how without seeming silly. Then this learned man of physics invoked it for me unbidden: “Klaatu barada nikto.’’

    Google it. Like Paul Horowitz, it’s kind of famous — a set of words from worlds unknown like those that he’s been waiting most of his life to hear.

  • ljk August 6, 2014, 15:41


    California wildfires temporarily suspend search for aliens

    By Melodi Smith and Kate Grise, CNN

    updated 8:13 AM EDT, Wed August 6, 2014

    (CNN) — Wildfires raging in Northern California briefly halted the search for extraterrestrial life on Tuesday.

    The Eiler Fire, burning some 200 miles north of Sacramento, forced employees at the SETI Institute’s Allen Telescope Array to evacuate and temporarily shut down all of their computers, Internet and power.

    “We can’t listen when all that is down,” said Seth Shostak, senior astronomer and director of SETI Research.

    At SETI — which stands for Search for Extraterrestrial Intelligence — scientists search the heavens for signs of extraterrestrial life by “listening” with an array of small satellite dishes.

    The blaze came within a mile of the facility, located near Hat Creek, California, on both the east and west, according to Shostak.

    “The fire on the west had jumped the road, burnt down our favorite lunch place, got within a mile of the telescopes,” he said. As the flames got closer, the staff fled to safer ground and shut down the satellites.

    “We just lost some search hours,” he said. “To expect that E.T. will somehow reach out at this moment, that would be very bizarre.”

    The Eiler Fire may not have cost the researchers their chance to find aliens, but it’s already burned more than 31,000 acres and threatened over 700 homes. However, fire officials say the fire is 35% contained and is expected to be fully contained by August 20th.

    The search for life can continue at SETI’s telescope array. The scientists were eventually given the all clear to return to the facility.

  • ljk August 11, 2014, 9:42


    The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. II. Framework, Strategy, and First Result

    J. T. Wright, R. Griffith, S. Sigurðsson, M. S. Povich, B. Mullan

    (Submitted on 5 Aug 2014)

    We describe the framework and strategy of the \^G infrared search for extraterrestrial civilizations with large energy supplies, which will use the wide-field infrared surveys of WISE and Spitzer to search for these civilizations’ waste heat. We develop a formalism for translating mid-infrared photometry into quantitative upper limits on extraterrestrial energy supplies.

    We discuss the likely sources of false positives, how dust can and will contaminate our search, and prospects for distinguishing dust from alien waste heat. We argue that galaxy-spanning civilizations may be easier to distinguish from natural sources than circumstellar civilizations (i.e., Dyson spheres), although Gaia will significantly improve our capability to identify the latter. We present a “zeroth order” null result of our search based on the WISE all-sky catalog: we show, for the first time, that Kardashev Type III civilizations (as Kardashev originally defined them) are very rare in the local universe.

    More sophisticated searches can extend our methodology to smaller waste heat luminosities, and potentially entirely rule out (or detect) both Kardashev Type III civilizations and new physics that allows for unlimited “free” energy generation.

    Comments: 15 pages, 4 figures, accepted for publication in the Astrophysical Journal

    Subjects: Popular Physics (physics.pop-ph); Astrophysics of Galaxies (astro-ph.GA)

    Cite as: arXiv:1408.1134 [physics.pop-ph]
    (or arXiv:1408.1134v1 [physics.pop-ph] for this version)

    Submission history

    From: Matthew Povich [view email]

    [v1] Tue, 5 Aug 2014 22:20:39 GMT (1296kb)


  • ljk August 12, 2014, 14:07

    Stepping Up the Search for ET

    By Katherine Noyes

    08/11/2014 1:41 PM PT

    Atmospheric pollution may not exactly be among mankind’s proudest achievements, but it’s certainly an incontrovertible sign that we are here. Could something similar help us find civilizations on other planets?

    That’s the premise behind one of several recently announced new approaches to the search for extraterrestrial intelligence.

    Pollutants like Earth’s in the atmospheres of other worlds could serve as biosignatures indicating the presence of advanced civilizations there, a team of researchers at the Harvard-Smithsonian Center for Astrophysics has suggested.

    So, to find the civilizations, we should look for the pollution.

    “People have searched for extraterrestrial civilizations by looking for radio signals and laser emissions — intentional transmissions — and haven’t found anything in the past 50 years,” Avi Loeb, chair of Harvard’s Department of Astronomy and director of the Institute for Theory and Computation within the Center for Astrophysics, told TechNewsWorld.

    “I thought about industrial pollution, which could be an interesting signature for an intelligent civilization,” added Loeb, who is a coauthor on the resulting paper, now available online in The Astrophysical Journal.

    Full article here:


    To quote:

    ‘A Powerful Carbon Dioxide Laser’

    The group is conducting the first SETI experiments ever performed at several telescopes, including the LOFAR radio observatory in Europe and the CARMA Observatory in California, Siemion noted.

    “With our collaborators, we’re also building observing systems to conduct the first SETI searches ever performed in the mid- and near-infrared portion of the electromagnetic spectrum,” he said.

    In the mid-IR range, for instance, the group is using the Infrared Spatial Interferometer at Mt. Wilson Observatory in California to search for both pulsed and narrow-band indicators of technology. “This novel facility actually uses a powerful carbon dioxide laser to convert mid-infrared light down to much lower frequencies where we can analyze it in the same way as our radio experiments,” Siemion pointed out.

    Also under way is an effort to fit several telescopes with new, near-IR photon counters that can detect a pulse of light only a nanosecond long — something “we think could be produced by a large pulsed laser operated by an advanced extraterrestrial civilization,” he said. “Near-IR photons can get through the dust between stars very easily, so we could see a signal like this from a very distant star.

    ‘The Only Way to Know Is to Look’

    How long before we find one of those civilizations — assuming they’re out there?

    “That’s difficult to say,” Siemion said.

    “On the one hand, we now know that there are hundreds of billions of planets in the galaxy, which means there are an awful lot of places life could get started,” he explained.

    “We also know that all of the prebiotic molecules, water and energy sources we think were necessary for life to arise on Earth are present in abundance elsewhere in the universe,” Siemion added.

    “However, we don’t have any idea what the probability is that these conditions will actually lead to life developing, or the probability that basic life evolves intelligence,” he added. “If we take the very, very large number of possible places life could emerge, and multiply it by a very small probability of it happening, we might still get just one.”

    In any case, “ultimately the only way we are ever going to know whether intelligent life exists elsewhere in the universe is to look for it,” Siemion concluded, “and that is precisely what SETI is — a scientific experiment designed to answer this fundamental question: Are we alone as technologically capable beings?”

  • ljk August 13, 2014, 13:16

    We Could Find Alien Life, but Politicians Don’t Have the Will (Op-Ed)

    By Seth Shostak, SETI Institute | August 12, 2014 09:09 pm ET

    This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

    While alien life can be seen nightly on television and in the movies, it has never been seen in space. Not so much as a microbe, dead or alive, let alone a wrinkle-faced Klingon.

    Despite this lack of protoplasmic presence, there are many researchers – sober, sceptical academics – who think that life beyond Earth is rampant. They suggest proof may come within a generation. These scientists support their sunny point of view with a few astronomical facts that were unknown a generation ago.

    In particular, and thanks largely to the success of NASA’s Kepler space telescope, we can now safely claim that the universe is stuffed with temperate worlds. In the past two decades, thousands of planets have been discovered around other stars. New ones are turning up at the rate of at least one a day.

    More impressive than the tally is their sheer abundance. It seems the majority of stars have planets, implying the existence of a trillion of these small bodies in the Milky Way galaxy alone. A deeper analysis of Kepler data suggests that as many as one in five stars could sport a special kind of planet, one that is the same size as Earth and with similar average temperatures. Such planets, styled as “habitable”, could be swathed by atmospheres and awash in liquid water.

    In other words, the Milky Way could be host to tens of billions of Earth’s cousins.

    Full article here:


    To quote:

    For perspective, consider that the proposed 2015 NASA budget has about US$2.5 billion for planetary science, astrophysics and continued work on the new James Webb space telescope – categories that encompass all the planetary searches described above and more. That is considerably less than one-thousandth of the total US federal budget. The budgets for SETI, which takes the third approach, are a thousand times less.

  • ljk August 13, 2014, 14:03

    Hairspray Chemical Could Aid Search for Alien Life

    By Charles Q. Choi, Space.com Contributor | August 13, 2014 11:01 am ET

    Chemicals once found in hairspray may serve as signs of alien life on faraway worlds, researchers say.

    These compounds may reveal that extraterrestrials have disastrously altered their planets, scientists added.

    To detect biomarkers, or signs of life, on distant worlds, scientists have often focused on molecules such as oxygen, which theoretically disappears quickly from atmospheres unless life is present to provide a constant supply of the gas. By looking at light passing through atmospheres of alien worlds, past studies have suggested future instruments such as NASA’s James Webb Space Telescope could detect telltale traces of oxygen.

    Full article here:


  • ljk August 15, 2014, 13:05

    As on this date in 1977, August 15, the famous Wow! Signal was detected at the now long-gone Big Ear radio telescope at the Ohio State University (OSU), I was looking up more information on the subject. I came across two items I think deserve some attention:




    Had the Wow! Signal been found today with modern detection and analysis equipment, would it have gained the notice it did? Was it an alien signal or terrestrial interference? We may never know.

  • ljk August 15, 2014, 13:08

    The end of Big Ear and what was the longest-running SETI program on Earth:



    OSU got rid of the radio telescope to make way for a football stadium, condos, and a golf course. Hope it was worth it.

  • ljk August 19, 2014, 10:04

    The Intelligent-Life Lottery

    George Johnson

    AUG. 18, 2014

    Almost 20 years ago, in the pages of an obscure publication called Bioastronomy News, two giants in the world of science argued over whether SETI — the Search for Extraterrestrial Intelligence — had a chance of succeeding. Carl Sagan, as eloquent as ever, gave his standard answer. With billions of stars in our galaxy, there must be other civilizations capable of transmitting electromagnetic waves. By scouring the sky with radio telescopes, we just might intercept a signal.

    But Sagan’s opponent, the great evolutionary biologist Ernst Mayr, thought the chances were close to zero. Against Sagan’s stellar billions, he posed his own astronomical numbers: Of the billions of species that have lived and died since life began, only one — Homo sapiens — had developed a science, a technology, and the curiosity to explore the stars. And that took about 3.5 billion years of evolution. High intelligence, Mayr concluded, must be extremely rare, here or anywhere. Earth’s most abundant life form is unicellular slime.

    Since the debate with Sagan, more than 1,700 planets have been discovered beyond the solar system — 700 just this year. Astronomers recently estimated that one of every five sunlike stars in the Milky Way might be orbited by a world capable of supporting some kind of life.

    That is about 40 billion potential habitats. But Mayr, who died in 2005 at the age of 100, probably wouldn’t have been impressed. By his reckoning, the odds would still be very low for anything much beyond slime worlds. No evidence has yet emerged to prove him wrong.

    Maybe we’re just not looking hard enough. Since SETI began in the early 1960s, it has struggled for the money it takes to monitor even a fraction of the sky. In an online essay for The Conversation last week, Seth Shostak, the senior astronomer at the SETI Institute, lamented how little has been allocated for the quest — just a fraction of NASA’s budget.

    “If you don’t ante up,” he wrote, “you will never win the jackpot. And that is a question of will.”

    Full article here:


    To quote:

    In “Five Billion Years of Solitude,” by Lee Billings, published last year, the author visited Frank Drake, one of the SETI pioneers.

    “Right now, there could well be messages from the stars flying right through this room,” Dr. Drake told him. “Through you and me. And if we had the right receiver set up properly, we could detect them. I still get chills thinking about it.”

    He knew the odds of tuning in — at just the right frequency at the right place and time — were slim. But that just meant we needed to expand the search.

    “We’ve been playing the lottery only using a few tickets,” he said.

  • ljk August 28, 2014, 13:10

    Search for ET – Look for Hot Spots!

    By Leonard David

    August 28th, 2014

    If you’re on the hunt for intelligent extraterrestrial life out there in the Cosmos, waste heat may be the signal of detection.

    A recent paper in The Astrophysical Journal is led by Jason Wright at Pennsylvania State University.

    Titled “The G Infrared Search For Extraterrestrial Civilizations With ˆ Large Energy Supplies. I. Background And Justification,” the extensive paper offers the view that any advanced civilization is likely to churn out large amounts of energy – and the energy should be visible in the infrared.

    “We argue that detectably large energy supplies can plausibly be expected to exist because life has potential for exponential growth until checked by resource or other limitations, and intelligence implies the ability to overcome such limitations,” explains Wright and his co-authors.

    Moreover, there’s the promise of using new mid-infrared surveys to spot the ETI hot spots, such as that of NASA’s Wide-field Infrared Survey Explorer (WISE).

    Full article here: