# Is it possible... \[ancient astronauts\] **URL:** \ **Category:** Factual Questions\ **Created:** [July 17, 2010, 9:51am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016 "2010-07-17T09:51:27Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 17, 2010, 9:26pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/21 "2010-07-17T21:26:02Z")
> [@](#): > > This is a much riskier assumption than your first one: you’re reasoning from a sample size of one about all possible civilization-creating races. There are groups of people even today who don’t use much metal, plastic, or glass; go back a couple hundred years and there are lots of them. Add a couple cultural or religious taboos against tampering with the Earth-God, and you’ve easily got civilization that uses only biodegradable materials. Steam-era technology is certainly possible in a wood-based world (although there’s no evidence trees had evolved back then, either), and possibly later technologies that we haven’t developed because we don’t have the need. I was going by the premise of the OP - a civilization that was launching satellites into space. I’d have a hard time accepting the idea of a civilization using only biodegradable materials doing that. ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [July 17, 2010, 9:33pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/22 "2010-07-17T21:33:12Z")
> [@Little\_Nemo](#): > > I was going by the premise of the OP - a civilization that was launching satellites into space. I’d have a hard time accepting the idea of a civilization using only biodegradable materials doing that. Back then, rubber trees were plentiful and covered the plains as far as the eye could see… ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 17, 2010, 9:41pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/23 "2010-07-17T21:41:34Z")
> [@](#): > > I’m not sure on either of these scores. I’m not confident that any material would survive intact enough to be recognizable for that long, and processed materials would have plenty of time to be de-processed. I think there are materials that don’t deprocess. I believe Aluminum, for example, is virtually never found in a pure state naturally. It’s pretty much always in compounds with other elements. But when you do purify it, it can stay uncorroded pretty much indefinitely. A piece of pure aluminum forms a coating of aluminum oxide on its surface and that prevents any further corrosion in the interior of the sample. So if some future geologist digs up nuggets of pure aluminum, he will know that it’s not a natural phenomena. ---
**Author:** ![peledre](https://avatars.discourse-cdn.com/v4/letter/p/779978/32.png) [@peledre](https://boards.straightdope.com/u/peledre)\ **Post date:** [July 17, 2010, 9:41pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/24 "2010-07-17T21:41:48Z")
I thought this thread was going to be about that Ancient Aliens show that was on History Channel a while back. ---
**Author:** ![peledre](https://avatars.discourse-cdn.com/v4/letter/p/779978/32.png) [@peledre](https://boards.straightdope.com/u/peledre)\ **Post date:** [July 17, 2010, 9:43pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/25 "2010-07-17T21:43:29Z")
Voyager 1 and 2 should be around for quite some time unless they get grabbed by a star or planet or something. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [July 17, 2010, 10:14pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/26 "2010-07-17T22:14:15Z")
> [@curiousGuy](#): > > …that, say 2.5 billion years ago on Earth, an entire race of intelligent beings evolved, got civilized, sent off satellites into outer space, then got wiped out by some utterly huge event, so that no trace of them can ever be discovered? Does the present argument that signs of life began around 2 billion years ago exclude any such possiblility? You might enjoy reading Stephen Baxter, In Evolution, an sf book, he has a small section on reasonably intelligent dinosaurs, and I believe he posits the kind if civilization you do, wiped out by the bombardment. In “Coalescent” he has intelligent life, nothing like ours, arising in the first few seconds of the universe. He is a hard sf writer, but like the outrageous. In answer, I suspect we’d never know. The billions of years of the early earth might have been enough time for intelligence to have evolved. We have very few rocks from back then, so I’d guess it is plausible that any traces could have been destroyed by geologic processes. Even synchronous satellites would have been pushed out of orbit by solar wind and micrometeorite hits in a few billion years, I’d guess. ---
**Author:** ![Dennis3240](https://avatars.discourse-cdn.com/v4/letter/d/eada6e/32.png) [@Dennis3240](https://boards.straightdope.com/u/Dennis3240)\ **Post date:** [July 17, 2010, 10:15pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/27 "2010-07-17T22:15:16Z")
> [@Frylock](#): > > I do wonder sometimes–if there had been cities like modern New York City built, say, two billion years ago, is it likely that there would be no trace of them left at all? > > It’s basically the same as asking how long it would take for all traces of our own civilzation to disappear if all the people disappeared today. > > I remember there was some book about this latter question, I never read it though. The book is entitled “Life Without People” It’s the same book the somewhat silly discovery show is based upon ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [July 17, 2010, 11:04pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/28 "2010-07-17T23:04:09Z")
It could be _The World Without Us_ by Alan Weisman or _The Earth After Us: What Legacy Will Humans Leave in the Rocks?_ by Jan Zalasiewicz. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [July 17, 2010, 11:14pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/29 "2010-07-17T23:14:10Z")
The Cthulhu Mythos involves several civilizations, none native to this planet, that predated the dinosaurs. OTTOMH, the Elder Things, The Great Race Of Yith, The Fungi From Yuggoth, and the Flying Polyps. I’ll see if I can dig up a timeline. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 17, 2010, 11:16pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/30 "2010-07-17T23:16:43Z")
> [@](#): > > How about exotic isotopes or elements? If our advanced civilization started messing around in nuclear physics, that is. The reason they’re exotic in the first place is because they have short half-lives. > [@](#): > > I think there are materials that don’t deprocess. I believe Aluminum, for example, is virtually never found in a pure state naturally. It’s pretty much always in compounds with other elements. But when you do purify it, it can stay uncorroded pretty much indefinitely. A piece of pure aluminum forms a coating of aluminum oxide on its surface and that prevents any further corrosion in the interior of the sample. So if some future geologist digs up nuggets of pure aluminum, he will know that it’s not a natural phenomena. There’s many different shades of “pretty much indefinitely”. A decent-sized chunk of aluminum might well survive for millions of years. But when we’re talking billions, it’s probably been subducted and re-emerged multiple times, and there’s no way it’d survive that. In other words, if you ever drop your keys in molten lava, forget about them, because man, they’re gone. ---
**Author:** ![The\_Other\_Waldo\_Pepper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_other_waldo_pepper/32/12370_2.png) [@The\_Other\_Waldo\_Pepper](https://boards.straightdope.com/u/The_Other_Waldo_Pepper)\ **Post date:** [July 18, 2010, 12:04am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/31 "2010-07-18T00:04:17Z")
> [@curiousGuy](#): > > I am not asking whether evidence might be found. Not on Earth anyway, because the kind of destruction I am talking about is where all of the near-surface stuff gets molten and reduced to their basic elements. > (Some lost satellite sent by them, homing in back to Earth would be nice :)) To quote WATCHMEN, “our past would be cancelled. Our struggle from the primal ooze, every childbirth, every personal sacrifice rendered meaningless, leading only to dust, tossed on the void-winds. Save for Richard Nixon, whose name adorns **a plaque upon the moon,** no human vestige would remain. Ruins become sand, sand blows away…” (I mean, who needs to build a satellite when there’s already one in orbit, right?) ---
**Author:** ![Superfluous\_Parentheses](https://avatars.discourse-cdn.com/v4/letter/s/8edcca/32.png) [@Superfluous\_Parentheses](https://boards.straightdope.com/u/Superfluous_Parentheses)\ **Post date:** [July 18, 2010, 1:18am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/32 "2010-07-18T01:18:15Z")
> [@The\_Other\_Waldo\_Pepper](#): > > Save for Richard Nixon, whose name adorns **a plaque upon the moon,** no human vestige would remain. Jeez. Good for him, though. Thanks for mentioning that. ---
**Author:** ![DocCathode](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/doccathode/32/18773_2.png) [@DocCathode](https://boards.straightdope.com/u/DocCathode)\ **Post date:** [July 18, 2010, 1:28am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/33 "2010-07-18T01:28:25Z")
I just remembered that there was a Star Trek Voyager episode with this premise. Long ago, a species of dinosaur (I don’t remember which one) evolve human level inteligence. For reasons I dare not remember, they left Earth in a vast space fleet. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [July 18, 2010, 1:38am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/34 "2010-07-18T01:38:39Z")
> [@curiousGuy](#): > > …that, say 2.5 billion years ago on Earth, an entire race of intelligent beings evolved, got civilized, sent off satellites into outer space, then got wiped out by some utterly huge event, so that no trace of them can ever be discovered? Does the present argument that signs of life began around 2 billion years ago exclude any such possiblility? > [@curiousGuy](#): > > I am not asking whether evidence might be found. Not on Earth anyway, because the kind of destruction I am talking about is where all of the near-surface stuff gets molten and reduced to their basic elements. > (Some lost satellite sent by them, homing in back to Earth would be nice :)) > > My point was more along whether a possibility of such intelligence (of the space-faring type) can be ruled out, and was there enough time for this to have happened before the timeline of current theories of when life in any form started? Ok, first of all, your 2.5 billion year timeframe is well after the last time in Earth’s history that the entire crust was melted or otherwise destroyed. We know this from geological evidence, chiefly the fact that we’ve found solid rocks older than that. Secondly, you postulate that a race of intelligent beings evolved- at which point I ask, “evolved from what?”. Presumably an intelligent species would be large complex multicellular animals comparable to vertebrates or arthropods in sophistication. Who would presumably have arisen in a complex ecosystem, which in turn evolved from simpler progenitors with a long evolutionary history. IOW, you would expect that their existence would have been proceeded by 500-1000 million years of fossil evidence. Paleontologists looking for evidence of the evolution of modern life have scoured the globe looking for fossils surviving from archaic sedementary rocks, and so far they’ve never found anything more complex than algae that old. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 18, 2010, 2:06am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/35 "2010-07-18T02:06:21Z")
> [@DocCathode](#): > > I just remembered that there was a Star Trek Voyager episode with this premise. Long ago, a species of dinosaur (I don’t remember which one) evolve human level inteligence. For reasons I dare not remember, they left Earth in a vast space fleet. They came from hadrosaurs. Another fictional example of this is Larry Niven’s _The Green Marauder_, in which it turned out that nearly a billion years ago there was an intelligent if slow-living (anaerobic metabolism) technological species that was killed off by the appearance of green plants and the oxygenation of the atmosphere. For something much more geologically recent, the Gandalara Cycle is set in a society of near-human hominids that evolved on the bottom of the dried up Mediterranean, whose civilization and species were erased when it refilled. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [July 18, 2010, 2:09am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/36 "2010-07-18T02:09:53Z")
> [@Lumpy](#): > > Ok, first of all, your 2.5 billion year timeframe is well after the last time in Earth’s history that the entire crust was melted or otherwise destroyed. We know this from geological evidence, chiefly the fact that we’ve found solid rocks older than that. > > Secondly, you postulate that a race of intelligent beings evolved- at which point I ask, “evolved from what?”. Presumably an intelligent species would be large complex multicellular animals comparable to vertebrates or arthropods in sophistication. Who would presumably have arisen in a complex ecosystem, which in turn evolved from simpler progenitors with a long evolutionary history. IOW, you would expect that their existence would have been proceeded by 500-1000 million years of fossil evidence. Paleontologists looking for evidence of the evolution of modern life have scoured the globe looking for fossils surviving from archaic sedementary rocks, and so far they’ve never found anything more complex than algae that old. 2.1 billion though is [another matter](http://www.sciencedaily.com/releases/2010/06/100630171711.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29). ---
**Author:** ![Jet\_Jaguar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jet_jaguar/32/3562_2.png) [@Jet\_Jaguar](https://boards.straightdope.com/u/Jet_Jaguar)\ **Post date:** [July 18, 2010, 2:14am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/37 "2010-07-18T02:14:34Z")
Geosynchronous orbits don’t really last forever, either. They decay somewhere in the order of several tens of thousands of years, due to being perturbed by the Moon, and eventually will crash back into the Earth. I suppose if these ancient dino-astronauts launched something into solar orbit it may still be circulating, but space is really huge and an ancient satellite would be awfully hard to spot. ---
**Author:** ![Measure\_for\_Measure](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/measure_for_measure/32/557_2.png) [@Measure\_for\_Measure](https://boards.straightdope.com/u/Measure_for_Measure)\ **Post date:** [July 18, 2010, 2:18am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/38 "2010-07-18T02:18:34Z")
> [@Der\_Trihs](#): > > 2.1 billion though is [another matter](http://www.sciencedaily.com/releases/2010/06/100630171711.htm?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciencedaily+%28ScienceDaily%3A+Latest+Science+News%29). For completeness I’ll note a dissenting view: > **[2.1 Ga Multicellular Colonial Organisms - Umm, Not](http://ediacaran.blogspot.com/2010/07/21-ga-multicellular-colonial-organisms.html)** > > 2.1 GA structures on black shale bedding surface. Scale bar 1 cm. (El Albani et al. 2010) The latest edition of Nature has a paper claiming... > **[2.1 Ga Multicellular Colonial Organisms - Umm, Not (update)](http://ediacaran.blogspot.com/2010/07/21-ga-multicellular-colonial-organisms_13.html)** > > I previously discussed why I don't think the 2.1 Ga structures found in Gabon are multicellular colonial fossils. Having looked at the Natu... ---
**Author:** ![Spoke](https://avatars.discourse-cdn.com/v4/letter/s/a88e57/32.png) [@Spoke](https://boards.straightdope.com/u/Spoke)\ **Post date:** [July 18, 2010, 3:20am UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/39 "2010-07-18T03:20:30Z")
We would have found fossilized tire tracks. 😉 ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [July 18, 2010, 5:32pm UTC](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016/40 "2010-07-18T17:32:55Z")
It’s a while since I’ve read it, but in “The Science of Discworld” by Terry Pratchett, Ian Stewart and Jack Cohen, the authors posit a crab civilisation, long predating our own, of which no trace is to be found in the present day. Of course they are not seriously claiming that such a civilisation existed - their point (as I remember it) is that time is so vast, the duration of a civilisation so short by comparison, and the forces of destruction so relentless and complete that we would expect to find no trace, had such a civilisation existed. [Previous page](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016.md?page=1) [Next page](https://boards.straightdope.com/t/is-it-possible-ancient-astronauts/547016.md?page=3)