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Civilization Before Homo Sapiens?

My doctor is a long-time friend who always stops during my annual physical to ask about what’s going on in the hunt for exoplanets. Last week he surprised me when, after I had described ways of analyzing a transiting planet’s atmosphere, he asked whether planets could give rise to civilizations in different epochs. Why just one, in other words, given that homo sapiens has only been around for several hundred thousand years? Our technological civilization is a very recent, and to this point a short-lived phenomenon. Were there others?

I was startled because Adam Frank (University of Rochester) and Gavin Schmidt (NASA Goddard Institute for Space Studies) have recently raised a stir with a paper on what they call the ‘Silurian Hypothesis,’ the name deriving from a Doctor Who TV episode referencing intelligent reptiles called Silurians who come to life when accidentally awakened. As the authors point out in their paper:

We are not however suggesting that intelligent reptiles actually existed in the Silurian age, nor that experimental nuclear physics is liable to wake them from hibernation. Other authors have dealt with this possibility in various incarnations (for instance, Hogan (1977), but it is a rarer theme than we initially assumed.

True enough, although it does pop up in science fiction from time to time. I’m remembering a 1989 tale from Barry Longyear that involved a fleet of starships returning to their home world to find that it is now being managed by humans. The starship crews — essentially intelligent dinosaurs — have been gone 70 million years, their civilization long obliterated on their home world. The novel Frank and Schmidt reference is James Hogan’s Inherit the Stars, in which evidence of an unknown early human technology is found on the Moon. Maybe readers can supply some other stories involving civilizations from deep time.

Digging Out the Evidence

Frank comes to this topic as a natural outgrowth, I think, of his earlier investigations of how industrial civilizations affect their home planets. All this involves issues of sustainability and climate alteration, using dynamical systems theory as a methodology to examine how species with energy-intensive technology alter planetary evolution (you can read more about this in my Astrobiology and Sustainability). Does an industrial civilization invariably cause detectable climate shift? Gavin Schmidt jogged Frank’s thinking on the topic by bringing up the question of prior civilizations, which raised the issue of just how we might detect such a culture.

Image: The inland seas in North America (Western Interior Seaway) and Europe had receded by the beginning of the Paleocene, making way for new land-based flora and fauna. If an early mammal had produced a civilization in this era, would we be able to find traces of it? Credit: Paleontology World.

We’re talking non-human cultures if we go back far enough, and with the passage of hundreds of millions of years, evidence becomes more than a little problematic. Frank has just written a piece for The Atlantic that pulls out the major themes of the paper. Was There a Civilization On Earth Before Humans? puts the matter succinctly. Because when you talk about direct evidence of an industrial civilization, we’re dealing with a geologic record that makes it all but impossible to probe past the Quaternary period, some 2.6 million years ago.

We can obviously study earlier eras, but as the authors point out, the largest extant surface area is in the Negev Desert, in southern Israel, which can take us back 1.8 million years. Earlier than the Quaternary, we rely on exposed surfaces unearthed through excavation, drilling or mining, while our study of ocean sediments faces the fact of recycling ocean crust, so that our evidence is for periods that post-date the Jurassic; i.e., we can go back some 170 million years.

This gets seriously intriguing, and I found myself reading The Atlantic piece and the original paper (citation below) with a compulsive fascination, maybe because when I was a kid, I used to think about becoming a paleontologist, digging up the remains of creatures from the days of the brontosaurus. But how much of that past world can we recover given how sparse the fossil record is? For Frank and Schmidt point out how little of life is captured this way. From the paper;

The fraction of life that gets fossilized is always extremely small and varies widely as a function of time, habitat and degree of soft tissue versus hard shells or bones (Behrensmeyer et al., 2000). Fossilization rates are very low in tropical, forested environments, but are higher in arid environments and fluvial systems. As an example, for all the dinosaurs that ever lived, there are only a few thousand near-complete specimens, or equivalently only a handful of individual animals across thousands of taxa per 100,000 years. Given the rate of new discovery of taxa of this age, it is clear that species as short-lived as Homo Sapiens (so far) might not be represented in the existing fossil record at all.

The survival of actual objects produced by such a civilization — think the Antikythera Mechanism from ancient Greece — is unlikely indeed. Our species has left countless artifacts that have yet to be recovered, if they ever will be. On a wider scale, we are learning much about detecting the effects of civilizations on the landscapes around them (here I think of aerial surveys finding building sites or burial mounds), but Frank and Schmidt note that the current rate of urbanization is less than one percent of the Earth’s surface. We don’t know where to look, and the likelihood of finding direct evidence of artifacts is remote in the extreme.

Would we know it, then, if an early mammal built a civilization in the Paleocene (60 million years ago)? Let’s assume a civilization lasting no more than 100,000 years, which turns out to be 500 times longer than our own civilization to this point. You would think that specific markers of industrial acthttps://arxiv.org/abs/1804.03748ivity would get through — these would include, perhaps, plastics, which seem to live forever. They do break down eventually, as the authors note, but the results are unclear:

The densification of small plastic particles by fouling organisms, ingestion and incorporation into organic ‘rains‘ that sink to the seafloor is an effective delivery mechanism to the seafloor, leading to increasing accumulation in ocean sediment where degradation rates are much slower (Andrady, 2015). Once in the sediment, microbial activity is a possible degradation pathway (Shah et al., 2008) but rates are sensitive to oxygen availability and suitable microbial communities. As above, the ultimate long-term fate of these plastics in sediment is unclear, but the potential for very long term persistence and detectability is high.

We might likewise find evidence like increased concentrations of metals. Maybe our relentless production of electronics will leave a trace in the concentration of rare-Earth elements in sediments for some successor species to identify. Of course, we can’t be comfortable about generalizing from our own activities to those of some hypothetical primeval civilization, but there is room for speculation nonetheless, and Frank and Schmidt look hard at fossil fuels, the burning of which releases carbon into the atmosphere, causing the balance of carbon isotopes to shift in what atmospheric scientists call the ‘Suess effect,’ a change in isotope ratios of carbon that is readily traced in the last century.

We do see ‘spikes’ in the geological record, though none that are ‘spiky enough’ to fit into the hypothesis of a Silurian civilization. Using our own ‘Anthropocene’ era as a guide, we are seeing a huge increase in atmospheric carbon levels much unlike the slower spikes of the Paleocene-Eocene Thermal Maximum (PETM), when the planet’s average temperature rose well above what we have today. Those much earlier spikes (56 million years ago) took hundreds of thousands of years to play out. A civilization’s signal in terms of carbon output is, at least judging from our own, much more sudden, though we have yet to learn how it will end.

We can’t rule out detection methods that could trace extremely short-lived events in ancient sediments, the authors conclude, but they would be extraordinarily hard to detect. Frank and Schmidt don’t believe any such civilization existed, but their paper asks a broader question that is relevant to exoplanet studies. What kind of effects does the collection of energy for building a civilization leave on its home world? Assuming there is feedback into planetary systems, we may be able to build a set of markers that could help us identify the process at work.

As Frank concludes in his Atlantic essay:

…our work also opened up the speculative possibility that some planets might have fossil-fuel-driven cycles of civilization building and collapse. If a civilization uses fossil fuels, the climate change they trigger can lead to a large decrease in ocean oxygen levels. These low oxygen levels (called ocean anoxia) help trigger the conditions needed for making fossil fuels like oil and coal in the first place. In this way, a civilization and its demise might sow the seed for new civilizations in the future.

Cycles of civilizations could thus occur, even if we have no evidence that they have previously taken place on Earth. The broader question is whether we can deduce a set of maxims telling us how biospheres evolve, and how the activities of their societies re-shape their world. Again we are seeding the debate over differing kinds of biosignatures and technosignatures that will inform our studies of the data gathered by the next generation of space and ground instruments.

The paper is Schmidt and Frank, “The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record?” published online by the International Journal of Astrobiology 16 April 2018 (abstract / preprint).

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{ 99 comments… add one }
  • Philip Tung Yep April 18, 2018, 11:08

    One of Larry Niven’s “Draco Tavern” short stories, “The Green Marauder” had a Chirpsithtra ramscoop pilot returning to the Solar System after a very long series of journeys (relativistic time dilation) and remembering fondly the beautiful civilization that had existed on Earth long ago. It was anaerobic and destroyed by the evolution of photosynthetic organisms.

    • Paul Gilster April 18, 2018, 11:15

      Yes! That brought back an old memory, and a good one. Thanks!

      • Linz April 19, 2018, 18:06

        Not to mention ‘Toolmaker Koan’ by John Mcloughlin.

  • John Kavanagh April 18, 2018, 11:57

    Star Trek Voyager had an episode “Distant Origin” involving sapient dinosaurs that settled in the Delta Quadrant, having left Earth before the KT impact. http://memory-alpha.wikia.com/wiki/Distant_Origin_(episode)

    • Paul Gilster April 18, 2018, 12:33

      Good catch. I don’t think I saw that episode, but I can always stream it.

      • J. Jason Wentworth April 18, 2018, 17:43

        Yes–they were descended from Hadrosaurus dinosaurs, if memory serves. Also:

        As Carl Sagan pointed out (in a lamentation about the lost books and knowledge from the ancient Library of Alexandria, in his book “Cosmos”), there are human civilizations that may have come and gone without leaving a trace. He wrote that every now and then, the ruins of such a culture, about which we knew nothing, are found–he named Ebla (see: http://en.wikipedia.org/wiki/Ebla ) as just one example of this. The Antekythera astronomical computer also raises the question: What else might the ancients have invented and known, which we know nothing about (and never will, unless artifacts are discovered)?

    • Christopher L. Bennett April 21, 2018, 20:59

      Two years before “Distant Origin,” Diane Carey and paleontologist James I. Kirkland (really) wrote a STAR TREK novel called FIRST FRONTIER, featuring a sentient species descended from raptor dinosaurs taken from Earth in the Cretaceous and using time travel to prevent the impact of the Chicxulub asteroid. Those dinosaurs were taken from Earth pre-sentience by aliens and evolved their civilization elsewhere. I’ve always liked to think the Voth from “Distant Origin” were taken by the same aliens.

      • Jeff Wright May 16, 2018, 16:44

        One from meat eaters, one from vegans…hmmm

  • Alex Tolley April 18, 2018, 11:57

    I think one would need to look for evidence of artificial manufactures or byproducts. Burning fossil fuels can be mimicked by exposure of fossil beds to fires, which in turn invalidates mercury levels in sediments. plastics that do not decompose (although we do have plastic eating bacteria – shades of that 1970’s BBC tv series Doomwatch), long lived artificial isotopes, remains of large concrete structures, complex fabricated artifacts of metal and plastic, perhaps even signs of genetic tampering.

    I would suggest that any signs would need local examination by a probe on an exoplanet. I don’t see any obvious way to detect these signs from afar if they are millions of years old.

    One feature that might be detectable is an artificial alteration of the landscape. We can detect craters hundreds of millions of years old. Symmetric lakes might leave traces for millions of years even after they are filled in.

    • ljk April 18, 2018, 14:52

      Perhaps we should revive that old plan to signal Mars with giant geometric structures in the Sahara Desert if we want our civilization to be noticed from a distance.

      https://en.wikipedia.org/wiki/Communication_with_extraterrestrial_intelligence#History

    • Linz April 20, 2018, 2:01

      Look for evidence of mining, resource depletion?
      I’m not sure how many plastics/synthetics would survive incorporation into rocks.
      Look for the most tectonically stable place on the planet & search?
      Look under flood basalts (surface or oceanic) of about the right age?
      Find the oldest unsubducted section of sea floor & take it apart to the bed rock?

  • Tom Mazanec April 18, 2018, 12:36

    Here is a look at this from the other end of time:
    http://archdruidmirror.blogspot.com/2017/06/the-next-ten-billion-years.html

    • david lewis April 24, 2018, 11:08

      Well, that’s a pretty dismal and defeatist look at the future. We should be grateful that that sort of view point isn’t too common or there would be no human species, period. We would never have left the trees and would have gone extinct rather than trying to utilize fire.

  • don wilkins April 18, 2018, 12:39

    More recently Gregory Benford and Larry Niven wrote two great books: Bowl of Heaven and Shipstar. Not only do they explain the disappearance of the dinosaurs but provide an unusual explanation as to why our sun is not part of binary.

    • Paul Gilster April 18, 2018, 14:40

      With volume 3 now close to completion! Wraps the sequence up, and should be well worth reading.

  • Keith Cooper April 18, 2018, 13:19

    A certain book by co-written by Stephen Baxter (I won’t name it so I don’t spoil it for anyone who hasn’t read it) ends with the realisation that there was another civilisation on the very early Earth.

    Another alternative to consider is that an intelligent civilisation may not have evolved on Earth before, but we could have been colonised long ago in the past and that colony died out.

    I wonder if Frank and Schmidt aren’t going about it the wrong way. Evidence in the geological record might not last, but phylogenetics can take us all the way back to LUCA and beyond. Evidence of past forms of life might be preserved in the genetic record better than in the geological record.

    • EBuchan-Kimmerly April 18, 2018, 19:03

      If you mean the”Long Earth” series with Sir Terry Pratchett, I can’t think of any reason for vaguebooking about it.

      • Keith Cooper April 19, 2018, 11:32

        No, I’m referring to one of his novels written with Arthur C Clarke. I’ve not read the Long Earth series, does that touch on this topic too?

      • Tom Mazanec April 19, 2018, 12:05

        I believe it is “The Light of Other Days” with Arthur C. Clarke.

      • Curt Wohleber April 19, 2018, 12:27

        Stephen Baxter’s “Evolution” featured a prehuman reptilian near-civilization. Man, that was a depressing book. A big theme was motherhood and the frequent failure of offspring to survive.

      • Mike April 19, 2018, 13:16

        I’m quite sure the correct title was provided by Wojciech J. further on down in the comments.

  • Robert April 18, 2018, 13:50

    People have claimed to have found artifacts and fossils predating human civilization. Some claim modern humans really go back possibly more than a million years. Recently found, the Gobekli Tepe site in southern Turkey is dated at 11,000 years ago during the Stone Age and long before the accepted birth of ‘civilization’ as we reckon it. It’s an entire temple complex which apparently was intentionally buried. Complex cave art goes back several tens of thousands of years.

    Perhaps a human technological society did exist in the remote distant past and experienced a sort of schism. The ‘go to the stars’ crowd left earth and the ‘back to nature’ crowd remained and renounced technology, actively destroying all evidence of it so their descendants would not be tempted.

    • Alex Tolley April 20, 2018, 12:58

      Some claim modern humans really go back possibly more than a million years. Recently found, the Gobekli Tepe site in southern Turkey is dated at 11,000 years ago during the Stone Age and long before the accepted birth of ‘civilization’ as we reckon it.

      11,000 ya is nothing like millions ya. Jericho may be of similar age to Gobekli Tepe. Obviously, human habotation in caves with paintings goes back tens of thousands of years.

      But detecting evidence of civilization millions of years old. That is difficult. Pre-industrial revolution civilization would be detectable if you found sites – a hit and miss affair. IIoannis Kokkinidis down thread suggests lead in sediments from smelting, but I doubt this is anything more than very local and certainly not as universally distinctive as the iridium layer at the KT boundary.

      I agree with arguments that we would fund easy to extract surface desposits of fossil fuels depleted if there was a technological civilization that preceded us. If they did not mine fossil fuels and extracted relately little metals, then a civilization that is equivalant to, e.g. Ancient Greece, would be hard to detect without luck in finding a site and possibly evidence of quarries. Poterry shards should last millions of years if buried, even incorporated into sedimentary rock. So far we find no evidence of anything that even remotely indicates that there were past civilizations.

  • Abelard Lindsey April 18, 2018, 14:00

    Why not look on the Moon for artifacts? There is no weathering on the Moon. So, artifacts left there may well last to be visible millions of years later. Mars and the asteroid belt would be other places to look.

    • ljk April 18, 2018, 14:56

      Another place to check is Earth’s Clarke Belt where satellites can remain in space for millions of years if not more.

      One space artist has already taken advantage of this idea by placing his art project aboard a Russian communications satellite in 2012:

      https://www.centauri-dreams.org/2013/01/18/the-last-pictures-contemporary-pessimism-and-hope-for-the-future/

      • J. Jason Wentworth April 18, 2018, 19:09

        Abelard and ljk, both of your mentioned locations–the Moon (and/or other airless bodies, either on the surface or in caves or lava tubes) and the Clarke Belt (which, along with the Earth-Moon L4 & L5 points’ vicinities, would be a place where a Bracewell probe could park indefinitely)–remain open as possible locations where interstellar probes, and even artifacts from ancient extrasolar expeditions, might be found, and:

        The asteroid belt, Jupiter’s L4 and L5 Trojan points (the many asteroids there, as well as the gravitational balances and possible orbits in those regions) and its moons (and the moons and L4 & L5 points of the other giant planets), stable orbits between the planets, and the stable intra-Mercury Vulcanoid zone are all places where such starprobes and/or extrasolar expedition artifacts might be found. Mercury, the Martian moons, and–for certain types of probes and/or extrasolar expedition “side trips”–the Oort Cloud (both comets and orbits in that zone) are also places where SETA/SETV (Search for Extra-Terrestrial Artifacts/Visitation) activities might bear fruit. Also:

        We are mislead by two psychological factors here. [1] Telescopes have scanned the solar system for centuries, and [2] for nearly sixty years, space probes (and people, in the case of the Moon) have conducted flyby, and/or orbital survey, and/or atmospheric probe, and/or lander (and/or rover) missions to all nine planets, most of their moons, and a few asteroids and comets. Now:

        These missions, plus all of the time that has passed since they began in 1959 (and the telescopic observation that has occurred for far longer) create a “belief-feeling” that the solar system has been searched thoroughly enough to find any alien hardware, if there was any there to be found. But this isn’t the case at all–SETA/SETV wasn’t a consideration in the space probe missions (no professional scientists were/are looking for possible artifacts [and for fear of ridicule, most scientists would resist considering the hypothesis of possible alien origins of anomalous data or images]). In addition:

        The other worlds that we have examined via spacecraft haven’t (with just a few exceptions) been photographed at sufficiently high resolution to reveal any possible artifacts (and any artifacts in caves or lava tubes, or buried, wouldn’t be visible at any resolution). Arthur C. Clarke’s statement in his 1968 book “The Promise of Space,” that “We may yet discover that ours are not the first footprints on the Moon” remains as current and valid as it was when he wrote it 50 years ago.

      • David Evans April 21, 2018, 8:50

        A geostationary satellite from very long ago would be below the present Clarke Belt, since the Earth rotated faster then! I expect we would have noticed it already.

        • Michael C. Fidler April 22, 2018, 23:58

          Dynamical evolution of near-Earth asteroid 1991 VG

          “The discovery of 1991 VG on 1991 November 6 attracted an unprecedented amount of attention as it was the first near-Earth object (NEO) ever found on an Earth-like orbit. At that time, it was considered by some as the first representative of a new dynamical class of asteroids, while others argued that an artificial (terrestrial or extraterrestrial) origin was more likely.
          Over a quarter of a century later, this peculiar NEO has been recently recovered and the new
          data may help in confirming or ruling out early theories about its origin. Here, we use the latest data to perform an independent assessment of its current dynamical status and short-term orbital evolution. Extensive N-body simulations show that its orbit is chaotic on time-scales longer than a few decades. We confirm that 1991 VG was briefly captured by Earth’s gravity as a minimoon during its previous fly-by in 1991–1992; although it has been a recurrent transient co-orbital of the horseshoe type in the past and it will return as such in the future, it is not a present-day co-orbital companion of the Earth. A realistic NEO orbital model predicts that objects like 1991 VG must exist and, consistently, we have found three other NEOs — 2001 GP2, 2008 UA202 and 2014 WA366— which are dynamically similar to 1991 VG. All this evidence confirms that there is no compelling reason to believe that 1991 VG is not natural.”

          “(i) Asteroid 1991 VG currently moves in a somewhat Earthlike
          orbit, but it is not an Earth’s co-orbital now. It has been
          a transient co-orbital of the horseshoe type in the past and it
          will return as such in the future.
          (ii) Extensive N-body simulations confirm that the orbit of
          1991 VG is chaotic on time-scales longer than a few decades.
          (iii) Our calculations confirm that 1991 VG was a natural satellite
          of our planet for about one month in 1992 and show that
          this situation may have repeated multiple times in the past and
          it is expected to happen again in the future. Being a recurrent
          ephemeral natural satellite of the Earth is certainly unusual,
          but a few other known NEOs exhibit this behaviour as well.
          (iv) A realistic NEO orbit model shows that although quite improbable,
          the presence of objects moving in 1991 VG-like orbits
          is not impossible within the framework defined by our
          current understanding of how minor bodies are delivered from
          the main asteroid belt to the NEO population.
          (v) Consistently, we find three other minor bodies —2001 GP2,
          2008 UA202 and 2014 WA366— that move in orbits similar to
          that of 1991 VG.
          (vi) NEOs, moving in 1991 VG-like orbits have a probability
          close to 0.004 of becoming transient irregular natural satellites
          of our planet.
          (vii) Our results show that, although featuring unusual orbital
          properties and dynamics, there is no compelling reason to
          consider that 1991 VG could be a relic of human space exploration
          and definitely it is not an alien artefact or probe.”

          Astronomers said we could never reach the Moon, so so much for the experts. :-}

  • andy April 18, 2018, 14:10

    It would be fun to do a bit of sci-fi with the Permian extinction. Rapid carbon dioxide release, global warming, make an analogy between the global distribution of Lystrosaurus and the global distribution of Bos taurus, etc.

    • Phil Tynan April 19, 2018, 1:53

      Interesting you should mention that, Andy. John McLoughlin’s Toolmaker Koan posits the existence of a fascinating dinosaurian civilization developing at the close the close of the Cretaceous, the Troodontid-derived Whileelin. In one chapter he discusses the geological imprint left by a technological civilization – the die-off of carnivores and larger animals save for the inexplicable increase in numbers and expansion in range of a few select large herbivores and the impoverished ecology to support them, and a layer of metallic sediment at the very stratum of a mass extinction event (shades of the K-T boundary – which, it transpires, was the Whileelin Armageddon).

      The book is an unremarked gem: well-written, painting a picture of a surprisingly convincing species of sentient reptile (even giving them their own somewhat awful version of the agricultural revolution which allowed for high-order specialization) and addressing the Fermi Paradox. He contends that culture is, in a very real sense, a Lamarckian evolutionary system, which leads almost inevitably to technological development and eventual extinction because the young toolmakers have not evolved the ability to curb their aggressive instincts and their developing weapons technology always overcomes the natural limits their physical endowments had once placed on their homicidal urges.

      In summary: a book well-worth reading. The West-Communist bloc backstory is dated – I hope! – but the corpus of the book is fascinating. And, pace Andrew Palfreyman, there is very little anthropocentric about the Whileelin.

      • Paul Gilster April 19, 2018, 6:38

        An unremarked gem indeed. I’ll find a copy of this.

  • Andrew Palfreyman April 18, 2018, 15:02

    One may as well call a spade a spade and recognise attempts to cast the ancient lizards as a technology-capable species as simply a particularly florid example of anthropocentrism. One might as well speculate about the precise shape of their soldering iron grip, or whether they were attired in top hat and tails and sporting a monocle.

    • J. Jason Wentworth April 18, 2018, 20:58

      I agree with you, but not in the way you expressed. The notion that only a technological civilization is worthy of attention and study (Paul *didn’t* say or imply this in his article; I’m referring to a widespread notion in modern societies around the world) is not only anthropocentric, but is “tempocentric”/”technocentric” (judged by the standards of this time and by technological societies, that is), and:

      Freeman Dyson made a comment (which is the header to Chapter Seven [“Intelligent Neighbors: How Far, How Many?”] in Ronald Bracewell’s 1974/75 book, “The Galactic Club: Intelligent Life in Outer Space”) which spoke to this. Dyson said, “I make a sharp distinction between intelligence and technology. It is easy to imagine a highly intelligent society with no particular interest in technology.” Also:

      Cetaceans–the whales and dolphins–show signs of having a civilization, as their complex songs and intelligence suggest. Horses also have one, as the veteran horseman Henry Blake (the author of “Talking with Horses,” “Thinking with Horses,” and “Horse Sense”) and his wife Leslie demonstrated via carefully-documented experiments. (The vocal/gestural language of domesticated horses has a considerably larger vocabulary than that of wild ones, as they recorded in their Equine/English dictionary, which is included in “Talking with Horses.”). In addition:

      In one of the other two books (I forget which), Blake also pointed out that the rules of polo, which are written, are all learned by horses who play the game (through perceiving their riders’ actions and reactions; they soon know what to do without rider input, including avoiding fouls), even though they cannot read or write. He also recorded, in “Talking with Horses,” instances of one of their horses listening to music, and then making his own simple music by rhythmically tapping a tinkling fence lining mesh with a front hoof, then improvising upon the melody (having spent time around horses, I’ve seen similar things).

    • Andrei April 20, 2018, 12:08

      A very good reply Andrew, speculation is good when there is some foundation for it.
      In this case there is none.

  • Michael April 18, 2018, 15:54

    I had to look twice but it did look like a structure on earth, very familiar…..6min 11 sec mark, upper left in the lava tube video. Just a play on the lighting I suspect…

    https://amp-space-com.cdn.ampproject.org/v/s/amp.space.com/39404-lava-tube-skylights-discovered-moon-images.html?amp_js_v=0.1&usqp=mq331AQGCAEYASgB

  • Al Jackson April 18, 2018, 15:54

    Reading this, thinking, Hyperborean Age.

  • NS April 18, 2018, 16:22

    One line of evidence against an ancient human industrial civilization is that when our own industrial civilization developed, near-surface deposits of coal, iron, oil etc. were readily available. Presumably an earlier industrial civilization would have used them up. However I’m not clear if this still applies over the timescale since the dinosaurs. Would these near-surface resources be replenished after that long?

  • Robin Datta April 18, 2018, 16:48

    A number of criteria contributed to the “sapiens” part of Homo sapiens. Body size was made possible by the circulatory and respiratory systems. Hemoglobin carries a lot more oxygen than an aqueous solution. Red blood cells allow for a lot more hemoglobin in blood without incurring the problems of viscosity. The partial pressure and volume of oxygen in air is a lot more than in aqueous solutions. The vertebrate circulatory system enables the transport of oxygen to sites quite remote from the ambient atmosphere, particularly a large brain.

    Arboreal existence and brachiation (locomotion by swinging from overhead branches) allowed the shoulder movement in three axes. Moving from branch to branch demanded depth perception that came with the large overlap of visual fields constituting binocular vision. This enabled looking at small nearby objects with stereoscopic vision, facilitating toolmaking.

    Persistent bipedal gait freed the upper extremities to handle objects. This was also helped by an opposable thumb of adequate length to allow a strong pinch.

    Decreases in jaw and tooth size and a persistent vertically upright stance allowed for changes is the pharynx and larynx that permitted complex speech.

    All of these features together were necessary, although no one nor partial combination of them was sufficient to put the “sapiens” in Homo sapiens.

  • DCM April 18, 2018, 17:49

    Let’s hope this idea doesn’t get politicized.
    Keep tabs on it and see if interpretation of any evidence follows an arc similar to aliens from Adamski’s humans to Grays that can be meaningfully compared to cultural changes and popularization of science.

    • J. Jason Wentworth April 18, 2018, 22:02

      The Aboriginal peoples of Australia and the Native Americans (I am part Native American myself) speak of the Star People, who came from far away in the sky. While this is an emotional topic among many White people because of its connotations about UFOs (I take no position on the *origins* of UFOs [the phenomena themselves, whatever they are, clearly exist, by the standards of evidence used in courts], but they do interest me), even Arthur C. Clarke wrote, in “The Promise of Space”–in the same chapter (#29, “Where’s Everybody?”) that mentions his own prosaically-explained UFO sightings and the Antikythera mechanism–that:

      “Visitors from space may have landed on our planet dozens–hundreds–of times during the long, empty ages while Man was still a dream of the distant future. Indeed, they could have landed on 90 percent of the Earth as little as two or three hundred years ago, and we would never have heard of it. If one searches through old newspapers, one can find large numbers of curious incidents that could easily be interpreted as visitations from space. That stimulating and eccentric writer Charles Fort made a collection of such occurrences in his book “LO!”, and one is inclined to give them more weight than any comparable modern reports, for the simple reason that they long predate current interest in space travel.”

  • Ioannis Kokkinidis April 18, 2018, 18:54

    While I do not consider myself to be a soil scientist, I have taken enough courses in pedology to know that it is quite possible to trace human civilization in the soil series. Roman civilization is traceable in the soils because of the lead concentration in the soils due to smelting. This particular Pb concentration drops after the Fall of Rome, in the Medieval West they used different smelting methods. There are several completely artificial soil series such as BIGAPPLE named after New York, it is made of dredged material:

    https://soilseries.sc.egov.usda.gov/OSD_Docs/B/BIGAPPLE.html

    I also remember another soil series, recently approved by SSSA, found in dump sites having at least 10% plastics. Alas, I do not remember its name. These soils will eventually turn into rocks, one way or another. The question is, when they do so, will their artificial origin be obvious to future civilizations?

    • J. Jason Wentworth April 18, 2018, 21:10

      You raise an interesting question, Ioannis. Growing up in the Blue Ridge Mountains of northern Georgia, I was astonished to see so much of what looked like “natural plastic”–thin laminae of transparent mica–inside the granite-sourced gravel in that area (a nearby mountain with a notched, tree-cleared summit was a local mica mine). It will be interesting to see if waste plastic (at least some of it) ends up taking on a similar appearance, with similar characteristics, when it becomes part of rocks.

  • EBuchan-Kimmerly April 18, 2018, 19:07

    Working backwards Robert A Sawyer wrote of a dinosaur civilization developed from Earth creatures who had been transported to another world.
    Fossil Hunter/ Far Seer/Foreigner.

    • Paul Gilster April 18, 2018, 19:44

      I’ve read a lot of Rob’s work but haven’t read these. Must get to them!

  • Winchell Chung April 18, 2018, 20:33

    Toolmaker Koan by John McLoughlin featured some survivors of a dinosaur civilization from 65 million years back.

    https://www.kirkusreviews.com/book-reviews/john-mcloughlin/toolmaker-koan/

    • Paul Gilster April 19, 2018, 6:42

      This one obviously has some traction, as it’s popped up multiple times in comments and also in emails.

  • Daniel Suggs April 18, 2018, 20:39

    Something I wrote for a daughter, many years ago:
    As it was told to me:
    Near the end of the Cretaceous, a sub-species of velociraptor developed tool making abilities and eventually built an industrial civilization. The Earth was entering an extended period of vulcanism and so they built colonies on the Moon and Mars to serve as back ups for their species. The interstellar asteroid which then hit their home planet came as a complete surprise and killed off most life. By the time the few surviving species began to recover and the planet was habitable again, the colonists had developed into a new species. They were completely adapted to lower gravity and had no desire to return to the constraints of Earth. Instead, they decided to spread to the rest of the solar system and beyond.
    In the intervening millions of years they have developed amazing technologies, colonized many worlds, and built a galactic civilization, but they have never forgotten where they came from.
    Their descendants continue to visit the home planet today, observing and waiting to see if homo sapiens will join them in space. They are commonly referred to as the Greys.

  • Patient Observer April 18, 2018, 20:42

    A plausible theory on the end of dinosaur civilization:

    https://i.pinimg.com/originals/b7/f4/8a/b7f48a5d1a8053e9d69ca2fe56ba7e7e.jpg

  • Michael Hutson April 18, 2018, 22:13

    Stranger From The Depths by Gerry Turner. https://www.amazon.com/dp/B000BTO0NI/?tag=stackoverflow17-20
    The discovery of a millions of years old synthetic diamond statue of a reptilian humanoid leads to the last survivors of a Mesozoic civilization.

    • Paul Gilster April 19, 2018, 6:39

      Good catch. I’d never heard of Turner’s book.

    • Tom Mazanec April 19, 2018, 12:15

      I read this when I was 12! Brings back memories!

  • David April 18, 2018, 23:29

    We still dont know the Minoan language and sadly Elba has been looted in the Syrian civil war.
    I dont think we can dismiss that dinosaurs could have reached a Paleolithic or even neolithic level of development. We have several species now that are close like the great apes,elephants,parrots and corvids. The last two are direct dinosaur descendants. . Perhaps trex could have used simple tools . Maybe there was never a major civilization but we may have had some near misses. Also we had a serendipitous route . In many ways we did not advance beyond ancient Egypt until the last 100 to 400 years. What if we ended up stuck in the middle ages and died out of a disease or even reverted to the neolithic. Look at the disaster that hit the American Indians. We came up with fanrastic theories about their achievements because we found a disease devastated civilization. Had that happened to all humanity all an alien vistor would find is the pryamids and a few cave men. I bet they might have thought elephants may gave built them.

  • xcalibur April 18, 2018, 23:31

    If I were in the distant future studying Holocene civilization, I would look for higher concentrations of metals, rare earths, plastics, and glass. There should also be large concrete structures in evidence, especially building foundations. If we shift away from fossil fuels to a nuclear economy (which will be necessary in the long-run), there would be concentrations of stable byproducts such as nickel and barium. Our satellites and space debris are clear evidence that we’ve ventured into near space, and should be long-lasting. If we succeed at space colonization (which again, will be necessary in the long-run), our space stations and outposts on the Moon/Mars etc will stand as monuments to our civilization.

    • Patient Observer April 19, 2018, 22:36

      Self-sustaining nuclear reactors were in operation well over one billion years ago per Wikipedia:

      https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor

      The article indicated that the “reactor” operated for several hundred thousand years with an average thermal output of 100 kW. It had a 3-hour operating cycle; go critical, heat up to a few hundred C which evaporated ground water in the reaction area. Without water as a moderator, the reaction would stop. The “reactor” would then cool down, ground water seep back in and the process repeats. It was essentially a nuclear powered geyser. Nature is amazing.

      • xcalibur April 22, 2018, 0:53

        Nature is amazing indeed, I’ve read about this before. I think a future archaeologist would be able to tell the difference between natural and artificial nuclear byproducts.

        I could delve into why we must shift to nuclear power sooner or later, but I think I’ll save those thoughts for a more relevant post.

        • Patient Observer April 22, 2018, 21:30

          Looking forward to it. I am a big fan of advanced nuclear power technology.

  • DJ Kaplan April 19, 2018, 4:34

    It would be nice to see some evidence before proceeding further.

    • AlexT April 20, 2018, 10:35

      Thanks, nice point :-)

  • Doug Muir April 19, 2018, 5:30

    The most long-term prominent remains of our civilization will be quarries and open-pit mines sunk in the rock of continental cratons (long-term stable continental cores). Some of these have involved the removal of a cubic kilometer of rock. Even if they fill with sediment they’ll show up very clearly to radar, sonar and seismic sensing, and they’ll be obviously artificial. Continental cratons are extremely stable — most of them are over a billion years old — so these will continue to be easily detectable for hundreds of millions of years.

    Doug M.

  • Doug Muir April 19, 2018, 5:38

    Weathering does take place on the Moon — just, very slowly. Solar wind, micrometeorites, moonquakes, thermal stress, and chemical interactions with the thin lunar exosphere are all working on the lunar landers. The current estimate is that they’ll erode away at about 1 millimeter per million years.

    That doesn’t sound like much, but it means that in a couple of million years the astronauts’ footprints will be visibly blurry, and in ten million or so they’ll be gone. After 20 million years the landers will be piles of wreckage; by 100 million, they’ll just be lumpy discolorations in the lunar regolith.

    For long-lasting evidence of humanity in space, you’re better off looking at the “graveyard orbits” just above geosynchronous, where geostationary satellites have been boosting themselves to die since the 1980s. There are dozens of dead satellites there now, some of them quite large, with more being added every year. Current thinking is that these orbits will be stable for tens of millions of years, and the satellites will easily be detectable by simple optical telescopes.

    Doug M.

    • ljk April 19, 2018, 9:25

      That is just what I said above in this thread:

      Another place to check is Earth’s Clarke Belt where satellites can remain in space for millions of years if not more.

      One space artist has already taken advantage of this idea by placing his art project aboard a Russian communications satellite in 2012:

      https://www.centauri-dreams.org/2013/01/18/the-last-pictures-contemporary-pessimism-and-hope-for-the-future/

    • ljk April 19, 2018, 9:35

      Doug M., this is the first time that I can recall where someone actually addressed just how long the human artifacts on the Moon will last and in what state they will be in, thank you. Most people just throw out a casual “millions of years” without any references or whether they put real thought into their answers.

      We already know that the United States flags planted by the Apollo astronauts are likely bleached out by the Sun if not in tatters in certain cases. Why they did not make them to last rather than for essentially photo ops during the mission is both disappointing and unfortunate.

      https://www.hq.nasa.gov/alsj/ApolloFlags-Condition.html

      FYI: I did not learn that the American flag planted by Apollo 11 actually fell over when the LM Eagle ascent stage took off from the lunar surface until I read Arthur C. Clarke’s 1976 SF novel Imperial Earth. The folks in the year 2276 were debating whether to restand the flag or leave it in the lunar dust for historical accuracy.

  • Wojciech J April 19, 2018, 5:45

    Stephen’s Baxter’s Light of Other Days based on Clarke’s story has a device allowing to see past(through wormhole IIRC that allows light to cross).Final revelation is a discovery that all life comes from sample stored and saved by civilization that existed 3 billion years ago and faced extinction through meteoric and vulcanic cataclysm.
    He names them Sisyphans.

    • Paul Gilster April 19, 2018, 6:37

      Another good one to add to my reading list. Thanks!

  • Wojciech J April 19, 2018, 5:52

    As to older human civilizations, that’s possible. Last glacial period meant that sea levels were much lower and there are possible civilization sites in North Sea like Doggerland.The whole area of Java Sea, Gulf of Thailand, parts of South China Sea were also plains.

    • Wojciech J April 19, 2018, 5:54

      Just a correction:by older I don’t mean hyperadvanced, possibly bronze age that later collapsed and regressed.That is still quite advanced and with possible detailed maths.

      • Michael C. Fidler April 20, 2018, 11:20

        The Comet Impact 12,900 years ago melted the North American ice sheets and flooded the Sundaland civilization and other ancient civilizations on the lower continental shelves around the world. This also ended the hunting Clovis culture and the megafauna that created it. This was the beginning of mans climb toward understanding the heavens as seen in the world’s oldest temple, Göbekli Tepe in southern Turkey. The pyramids, stonehenge and other megalithic structures built right up to the 1600’s were created for this purpose. Hopefully in the not too distant future they will be able to look under the sundaland ocean like they did with the Lidar images of the jungle covered Mayan temples recently. Then we may have a much better understanding of the Ice Age civilizations that existed before the flood.

        Very good books on the subject of Sundaland.

        Eden in the East: The Drowned Continent of Southeast Asia.
        By Stephen Oppenheimer

        UNDERWORLD: The Mysterious Origins of Civilization.
        By Graham Hancock

        Sundaland.

        https://atlantisjavasea.com/2015/09/29/sundaland/

        Did A Comet Impact Push Humans Into Technological Overdrive …

        https://www.universetoday.com/135240/comet-impact-push-humans-technological-overdrive/
        Apr 25, 2017 – For over a decade, there have been scientists who have argued that this period was the result of a comet hitting Earth. Known as the Younger Dryas Impact Hypothesis (aka. the Clovis Comet Hypothesis), the theory is largely based on ice core samples from Greenland that show a sudden global temperature change.

        Ancient stone pillars offer clues of comet strike that changed human history.

        https://phys.org/news/2017-04-ancient-stone-pillars-clues-comet.html

        The Younger Dryas Impact Hypothesis Since 2007.

        https://cosmictusk.com/hancock-younger-dryas-impact-hypothesis-since-2007/

        Mammoths loved Doggerland too – judging by the treasures recovered by North Sea trawlers.

        https://twitter.com/jamie_woodward_/status/640955156172009472

        http://www.disassociated.com/images/posts/doggerland_map.jpg

      • Michael C. Fidler April 22, 2018, 2:04

        You’re going to love this one!

        A 20,000-year-old transformer found in Kosovo.

        Photographer and researcher Ismet Smaili (Ismet Smaili) discovered a mysterious artifact in the mountains on the territory of Kosovo. This object externally is an unusual stone with an integrated electromagnetic coil.

        And the coil of copper wires is not simply inserted into the cut groove, but it makes up a whole with the stone, as if the stone was melted, and then gave it the necessary shape to create a transformer.

        In addition to the stone, the coil with copper wires, the artifact contains an insulator whose composition differs from the surrounding material and having convex bands in a circle resembling a carving and it is also fused into a stone, like the coil itself, and on the other side of the stone, there are 4 Symmetrically located openings, which most likely represent holes for wires and collect energy received from the transformer (phase).

        https://cdn.disclose.tv/sites/default/files/styles/inline/public/img/inline/2018/01/01/image.png?itok=zUly1-uc

        https://youtu.be/Fb8LS72ph-Y

        • Alex Tolley April 22, 2018, 20:07

          Not exactly a good site for information.

          https://www.snopes.com/tag/disclose-tv/

          I would suggest this is a hoax.

          • Michael C. Fidler April 23, 2018, 11:54

            Definitely, but it is very convincing, just wondering if it came from a russian Tsar bomb explosion or Chernobyl either way it’s a hot item!
            ;-)

  • ljk April 19, 2018, 9:43

    The 1984 SF novel West of Eden by Harry Harrison is a what-if story about an Earth where the dinosaurs were not rendered extinct (or became birds) 65 million years ago, as the space rock/comet missed the planet. Instead they evolved into intelligent beings with their own civilization, while humans are essentially prehistoric and in danger of being wiped out by the Yilane as Harrison calls the smart dinosaur descendants.

    http://prehistoricpulp.blogspot.com/2007/08/west-of-eden-by-harry-harrison-1984.html

    Quoting from the above blog article:

    What works best about the novel is the Yilane. Harrison spent a great deal of time crafting the species and actually sought out the help of two scientists in designing their biology and their language. Females are dominant, with the males giving birth. Their entire society is defined by their cold-blooded physiologies: They have no concept of metallurgy, because their bodies can’t stand the heat of an open flame, so their civilization is instead based on millions of years of selective breeding and genetic manipulation of other organisms. They make fascinating villains. Still, from a purely scientific point of view, it should be pointed out that the Yilane are impossible given it takes a warm-blooded metabolism to support human-like intelligence. And the species seems a little too alien for anything that could have evolved on earth. Why Harrison chose to have them descend from mosasaurs rather than a land-dwelling dinosaur is a mystery to me.

    • Paul Gilster April 19, 2018, 10:00

      Yes, I’m glad you mentioned West of Eden, Larry. I recall reading this one not long after it came out, but I was having trouble recalling the author and title.

  • ljk April 19, 2018, 13:45

    Just something new to add into the data mix:

    Age of dinosaurs may have been spurred by prior mass extinctions

    A string of significant climate changes during the Carnian Pluvial Episode of the Triassic Period led to global mass extinctions that may have spurred the rise of dinosaurs, according to findings published in Nature Communications.

    “The extinction didn’t just clear the way for the age of the dinosaurs, but also for the origins of many modern groups, including lizards, crocodiles, turtles and mammals — key land animals today,” said study co-author Mike Benton.

    Full article here:

    https://www.upi.com/Science_News/2018/04/16/Mass-extinction-paved-the-way-for-rise-of-the-dinosaurs/6451523898120/

    To quote:

    The earliest dinosaur species show up in the fossil record around 245 million years ago, at the beginning of the Triassic Period. Dinosaurs were relatively rare, however, until roughly 13 million years later.

    A survey of ancient rock deposits in Northern Italy’s Dolomites revealed the suddenness with which dinosaurs overwhelmed the landscape. There are almost no dinosaur footprints in the Triassic Period, but after the seismic events during the Carnian, the earliest age of the Late Triassic epoch, dinosaur footprints become ubiquitous.

    Surveys of the fossil records recovered from rocks in Argentina and Brazil revealed a similarly timed explosion of dinosaur skeletons.

    “We were excited to see that the footprints and skeletons told the same story,” Massimo Bernardi, a researcher at the University of Bristol, said in a news release. “We had been studying the footprints in the Dolomites for some time, and it’s amazing how clear cut the change from ‘no dinosaurs’ to ‘all dinosaurs’ was.”

    The rise of the dinosaurs corresponds with the tail end of the Carnian Pluvial Episode, a series of cataclysmic climate shifts that inspired dramatic biotic turnover on land and in the seas. Previous studies suggest a series of explosive volcanic eruptions in western Canada precipitated periods of global warming and acid rain.

    During the latest study, scientists found evidence of dramatic climatic shifts in the rock sequences collected from the Dolomites.

    • Robin Datta April 21, 2018, 16:36

      Every mass extinction paved the way for the next version of flora & fauna. The extant plants at the time of the dinosaurs did not include the angiosperms, the flowering plants, whose branching trees can produce continuous canopies permitting locomotion over substantial distances from trees to trees by brachiation. One can see pictures of today’s coniferous forests to note the absence of a canopy.

      Absent this, the driving force for evolving binocular vision and for three-axis freedom of shoulder movement after descent from the trees is also absent: and these are major aspects of toolmaking and toolhandling.

      The right body size is also essential for brachiation: a shrew would be too small, and a a gorilla too big. The shrew has no brachiation in its ancestry, although primates are postulated to have descended from shrew-like ancestors; the gorilla had a common brachiating ancestor with us, and has both binocular vision and three axis shoulder movement.

  • Linz April 19, 2018, 18:12

    Larger ceramics (engine blocks, toilets etc) should survive well.

  • Emily April 19, 2018, 19:45

    I would think there would be enormous amounts of unambiguous evidence in the form of stonework. Not just ‘sexy’ things like statues and carved columns, but billions and billions of scattered stone blocks and bricks scattered across the entire surface of the world. All of them pre-made fossils. I expect foundations and layouts of some cities would ‘fossilize’ as original material, a ring of stonework, and an interior of different fill.

    Unlike fossils of living creatures which need very specific conditions to be fossilized and preserved, there are enormous amounts of human made artifacts (particularly worked stone) which need absolutely nothing to preserve them other then just being buried.

    I’m confident that any civilization even remotely like ours or that made it to a global iron age would leave abundant and unmistakable evidence that would be detectable by even the most cursory examination of the geologic record.

    • Alex Tolley April 21, 2018, 11:14

      The problem is finding them. After millions of years they won’t be located on coastlines and rivers where they were built. With sea lel changes, they may be deep underwater on continental shelves or well inland. Global surveys would need to be able to map the subsurface very well as the cities will probably leave no clues on the surface.

      New sites are being found today that were missed by inhabitants after just a few thousand years, indicates the difficulties. Just imagine predicting the locations of cities in the Cretaceous or even the Eocene from todays geological maps .

  • Kytshar April 19, 2018, 20:03

    Note that the authors conclude that is uncertain if past industrial civilizations would leave enough evidence of their existence after millions of years. Then, doesn’t that mean that past pre-industrial civilizations are indetectable? Let’s say, for example, that just before the K-T extinction event, a civilization of sapient dromeosaurs arose with a technology level equal to that of the Roman Empire at its territorial peak. We would never know if that was the case.

    • Alex Tolley April 21, 2018, 11:18

      What the authors are asking for is more complete analysis of cores in case a number of their signatures appear. For example, has anyone ever bothered to look for nano plastic material in ancient sediments? Why would they even look?

      As it is probably a waste of time and resources, I expect their idea will fall on deaf ears unless some grad student decides to take it on.

  • ljk April 20, 2018, 10:07

    Life After People

    A look at what would happen if humans disappeared from Earth. How would ecology adapt and change to cope with the lack of human beings, and what will Earth look like into a future without humans.

    https://www.youtube.com/watch?v=GyEUyqfrScU

    • Robert April 20, 2018, 13:35

      The short lived 2011 tv series Terra Nova explored humanity surviving a dying world by going via time travel to the distant past, existing during the age of dinosaurs. A similar plot was explored in Star Trek’s All our Yesterday’s where a planets population escapes an impending nova of their sun.

  • Christopher L. Bennett April 21, 2018, 21:12

    STARGATE SG-1 postulated that the Ancients, the humanlike beings who created the Stargate network, evolved as a separate human species on Earth 3 million years ago. I found this marginally plausible, since that’s recent enough for them to be a separate hominid branch, and since they were said to have manipulated human evolution and maybe interbred with humans, explaining why we looked just like them. However, later seasons abandoned this idea in favor of the sillier, more cliched notion that the Ancients had come from a distant galaxy and colonized Earth. Either way, though, they were still shown to have had a civilization on Earth millions of years ago. (And also tens of thousands of years ago. The timeline of all this was very inconsistent.)

  • Silent Hunter April 22, 2018, 7:25

    As was pointed out in ‘Doctor Who’ , the Silurians were in fact from the Eocene period.

    • ljk April 23, 2018, 16:11

      Speaking of Doctor Who – and the first Dirk Gently novel in what was clearly a wholesale reuse of a plot idea – all life on Earth began thanks to the inadvertent explosion of a nuclear (I think) powered alien starship that was visiting our planet waaaay back in the day.

      It reminds me of a theory I first read back in the early 1970s that our biological ancestors may have come from the discarded refuse of ETI explorers who landed on the very early Earth. I wonder how we could ever prove that?

      • Alex Tolley April 24, 2018, 15:02

        (…) our biological ancestors may have come from the discarded refuse of ETI explorers who landed on the very early Earth (…)

        That is Tom Gold’s theory, I believe.

        If we are the result of panspermia, we probably cannot prove that definitively. What we can do at some point is to catalog life elsewhere and try to make sense of the similarities and differences. For example, suppose all our samples from nearby stars were similar but different from us, whilst a star farther away had life similar to us. That would suggest a linkage that is probably due to some form of panspermia that only affected Earth, not neighboring stars.

        Alternatively, if there was some proof that life could not have evolved on Earth directly, perhaps with evidence from other worlds, then the panspermia hypothesis would gain relative traction, although, for [astro]biologists, it just moves the problem back a few steps. It would be ironic is the “irreducible complexity” idea of the creationists proved correct for life on Earth.

  • ljk April 24, 2018, 9:31

    Viruses, ET and the octopus from space: the return of panspermia

    April 24, 2018

    A major paper revives the oft-mocked theory that life on Earth began in a rain of cosmic microbes. Stephen Fleischfresser reports.

    The peer-reviewed journal Progress in Biophysics and Molecular Biology recently published a most remarkable scientific paper. With 33 authors from a wide range of reputable universities and research institutes, the paper makes a seemingly incredible claim. A claim that if true, would have the most profound consequences for our understanding of the universe. Life, the paper argues, did not originate on the planet Earth.

    The response?

    Near silence.

    The reasons for this are as fascinating as the evidence and claims advanced by the paper itself. Entitled Cause of the Cambrian Explosion – Terrestrial or Cosmic?, the publication revives a controversial idea concerning the origin of life, an idea stretching back to Ancient Greece, known as panspermia.

    Full article here:

    https://cosmosmagazine.com/biology/viruses-et-and-the-octopus-from-space-the-return-of-panspermia

    The paper is online here:

    https://www.sciencedirect.com/science/article/pii/S0079610718300798?via%3Dihub

    • Alex Tolley April 24, 2018, 16:33

      I read the paper. I’m not surprised it has been met with silence.

      Sadly, their suggestions for testing their hypothesis[es] is rather weak, IMO. I think the Zubrin article on panspermia (https://www.centauri-dreams.org/2017/12/21/interstellar-communication-using-microbes-implications-for-seti/) was rather better, IMO, with far more testable predictions.

      If the authors are correct, then the implication is that all, or most, life are based on a common biology, that is then spread. If comets are one major vector, then life must have been part of the planetary disk when the solar system formed. We would expect comets to harbor life below their surfaces, and this could be tested by retrieving samples or by direct examination by a spacecraft. All these samples would bear the same biology as terrestrial life.

      One problem might be that the comets are actually bearing life that was emitted from Earth, not from elsewhere. This might be testable too.

      Whatever one’s thoughts on panspermia, it does seem to me that we should put a lot more effort into devising instruments that can detect life and analyze it remotely, as well as sterile sample return missions. I suspect this will only happen when the cost of access to space declines significantly, as well as cheaper spacecraft, that can be funded by institutions that can afford to develop such blue sky experiments.

      The development of space junk retrieval technology might provide a spinoff advantage by serendipitously capturing a rare meteor that should be free of contamination, even possibly cometary material falling towards Earth.

      Incontrovertible proof of life from a solar system body would clearly open up funding for more extensive studies.

      Philosophically, suppose the panspermia hypothesis is true, what does imply for any “prime directive”? We would expect all living worlds to be based on biology very similar to Earth. This would mean that cross-contamination would be a problem, possibly quarantining all living worlds. Alternatively, that we are already being affected by extraterrestrial viruses, perhaps that implies that any contamination may be limited, at least on Earth where we have the technology to counter lethal epidemics. Exoplanets, however, may be highly vulnerable to contamination from Earth.

  • stephen April 24, 2018, 21:45

    The website Goodreads has a list, including works by a well-known pseudoscientist…I noticed none of you mentioned him, and I wondered if you were hoping nobody else would.
    https://www.goodreads.com/shelf/show/ancient-astronauts

    TV Tropes has lists of examples of the idea in books, movies, TV, etc. It’s an addictive website.
    http://tvtropes.org/pmwiki/pmwiki.php/Main/AncientAstronauts

    Kenneth Bulmer, using the pseudonym of Manning Norvil, wrote 3 novels taking the ancient astronauts idea seriously. I started to read one, and I don’t remember if I finished it. I think I got bored. I think it was just a stale retread of fantasy or sword-and-sorcery fiction, as I recall.

    https://www.amazon.com/s/ref=dp_byline_sr_book_1?ie=UTF8&text=Manning+Norvil&search-alias=books&field-author=Manning+Norvil&sort=relevancerank

    James Rollins has written thriller novels dealing with ancient advanced technology, not all with non-humans.

    I saw something, maybe it on the Science Channel, which describes some very rugged terrain in Madagascar, with underground caverns where there might be an unknown group of humans or hominids hiding. There are lots of unexplored places in the world.

    Antarctica, for example. Wikipedia’s article on Lake Vostok says there are almost 400 subglacial lakes. What could be in there? Antarctica was once warm, and maybe a prehuman civilization stuck to the one continent and had very little presence on the other continents.

    Maybe the mass extinctions were actually the result of worldwide wars.

    Maybe once the tech level was high enough, they used nanotechnology to clean up the pollution, empty out the landfills, put the mineral wealth back into the ground, dissassemble their monuments and then they traveled into space to watch what happens next.

    How long would it take for trains and cruise ships to be unrecognizable?

  • Lenard Segnitz April 25, 2018, 16:15

    If there was an ancient civilization I’d say they didn’t build it up with fossil fuels since we found so much of it ourselves. It’s not impossible to build up a technologically advanced civilization without fossil fuels just a lot harder.

    • Curious June 19, 2018, 19:59

      Wood is only about 1/3 the energy density of crude. If their world had more trees or growing faster or the civilization smaller, there is no reason they couldnt have done without crude – we didnt have it until what the 1800s? Wood can also be gasified or other plants used for synthesizing hydrocarbons. Maybe they used more copious microbial biomass. Its all fun speculation

  • ljk April 26, 2018, 9:48

    How The Building Blocks Of Life May Form In Space

    Press Release – Source: AIP

    Posted April 25, 2018 8:22 PM

    In a laboratory experiment that mimics astrophysical conditions, with cryogenic temperatures in an ultrahigh vacuum, scientists used an electron gun to irradiate thin sheets of ice covered in basic molecules of methane, ammonia, and carbon dioxide.

    These simple molecules are ingredients for the building blocks of life. The experiment tested how the combination of electrons and basic matter leads to more complex biomolecule forms — and perhaps eventually to life forms.

    “You just need the right combination of ingredients,” author Michael Huels said. “These molecules can combine, they can chemically react, under the right conditions, to form larger molecules which then give rise to the bigger biomolecules we see in cells like components of proteins, RNA or DNA, or phospholipids.”

    Full article here:

    http://astrobiology.com/2018/04/how-the-building-blocks-of-life-may-form-in-space.html

    To quote:

    “You have to remember — in space, there is a lot of time,” Huels said. “The idea was to get a feel for the probability: Is this a realistic yield, or is this a quantity that is completely nuts, so low or so high that it doesn’t make sense? And we find that it is actually quite realistic for a rate of formation of glycine or similar biomolecules.”

    Reference: “Glycine Formation in CO2:CH4:NH3 Ices Induced by 0-70 eV Electrons,” Sasan Esmaili, Andrew D. Bass, Pierre Cloutier, Léon Sanche, and Michael A. Huels, 2018 Apr. 24, Journal of Chemical Physics

    http://aip.scitation.org/doi/full/10.1063/1.5021596

  • ljk April 28, 2018, 13:24

    Clues to recovery from mass extinction

    April 22, 2018

    About 252 million years ago, more than 90 percent of all animal life on Earth went extinct. This event, called the “Permian-Triassic mass extinction,” represents the greatest catastrophe in the history of life on Earth. Ecosystems took nearly five million years to recover and many aspects of the event remain a mystery.

    A research team, led by scientists from Arizona State University and funded by NASA and the National Science Foundation, is helping to understand why this extinction event happened and why it took life so long to recover. The study, published in Science Advances, was led by ASU School of Earth and Space Exploration graduate student Feifei Zhang, with direction from school faculty member Ariel Anbar.

    Full article here:

    https://www.astrobio.net/also-in-news/clues-to-recovery-from-mass-extinction/

  • ljk May 9, 2018, 12:18

    Snowball Earth due to plate tectonics?

    By Eleanor Imster in Earth | May 9, 2018

    New research suggests that as great land plates began to shift and move on Earth’s surface, our world became what geologists call a Snowball Earth.

    http://earthsky.org/earth/snowball-earth-due-to-plate-tectonics

  • ljk June 8, 2018, 12:38

    Bees Appear Able to Comprehend the Concept of Zero

    The insects correctly ordered an absence of black dots as “less than” a group of black dots.

    By Ashley Yeager | June 7, 2018

    Honeybees can identify a piece of paper with zero dots as “less than” a paper with a few dots. Such a feat puts the insects in a select group—including the African grey parrot, nonhuman primates, and preschool children—that can understand the concept of zero, researchers report June 7 in Science.

    “The fact that the bees generalized the rule ‘choose less’ to [blank paper] was consequently really surprising,” study coauthor Aurore Avarguès-Weber, a cognitive neuroscientist the University of Toulouse, tells The Scientist in an email. “It demonstrated that bees consider ‘nothing’ as a quantity below any number.”

    In past studies, researchers have shown that bees can count up to five, but whether the insects could grasp more-complex ideas, such as addition or nothingness, has been unclear.

    In the latest study, Avarguès-Weber and her colleagues tested the bees’ ability to comprehend the absence of a stimulus by first training the insects to consistently choose sheets of paper either with fewer or more dots by landing on a tiny platform near the paper with the dots. If the bees chose correctly, they were rewarded with a sugary drink.

    The bees performed the task surprisingly well, Avarguès-Weber says. “The fact that they can do it while we were also controlling for potential confounding parameters confirms their capacity to discriminate numbers.”

    The team then tested the bees’ ability to distinguish a blank piece of paper, or what the researchers call an empty set, from a sheet with one dot and found the insects chose correctly about 63 percent of the time. The behavior reveals “an understanding that an empty set is lower than one, which is challenging for some other animals,” the researchers write in the paper.

    Full article here:

    https://www.the-scientist.com/?articles.view/articleNo/54776/title/Bees-Appear-Able-to-Comprehend-the-Concept-of-Zero/

    To quote:

    That bees can use the idea of “less than” to extrapolate that nothing has a quantitative nature is “very surprising,” says Andreas Nieder of the University of Tübingen in Germany who was not involved in the study. “Bees have minibrains compared with human brains—fewer than a million neurons compared with our 86 billion—yet they can understand the concept of an empty set.”

    Nieder suggests honeybees, similar to humans, may have developed this ability to comprehend the absence of something as a survival advantage, to help with foraging, avoiding predation, and interacting with other bees of the same species. The absence of food or a mate is important to understand, he says.

  • Bill Hapgood July 10, 2018, 18:21

    In this thread an obscure but nevertheless very interesting book from England circa 1993: “Who Lies Sleeping: The Dinosaur Heritage and the Extinction of Man,” by Mike Magee, via Askwhy publications. This is the discussion of Mr. Magee’s hypothetical “anthroposaurus sapiens” around 66 million years ago and possible chemical evidence of the full presence of an industrial civilization at the K/T Boundary. The book is well written and well presented: I even imagined, by convergent evolution, that Magee’s anthroposaurus sapiens might have looked, if they ever really existed, like Star Trek Deep Space Nine’s Cardassians!

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