:cthulu: seems somewhat appropriate for this.
This article came out about a year ago but I just came across it the other day.
Quote
THE SILURIAN HYPOTHESIS: HOW DO WE KNOW THAT HUMANS WERE THE FIRST CIVILIZATION ON EARTH?
BY ARISTOS GEORGIOU ON 4/18/18 AT 10:45 AM
Was There Civilization On Earth Before Humans?
What if another industrial civilization had existed on Earth tens of millions of years ago, long before humans, but all traces of it have now been lost?
While it may seem like an absurd idea, this thought experiment is the focus of a new scientific paper authored by Adam Frank, an astrophysicist from the University of Rochester, and Gavin Schmidt, director of the NASA Goddard Institute for Space Studies.
They have named the paper "The Silurian Hypothesis" after a fictional race of intelligent, bipedal reptiles from the British sci-fi series Doctor Who—known as the Silurians—that supposedly lived on Earth hundreds of millions of years ago.
In the study, which has been published in the International Journal of Astrobiology, Frank and Schmidt ask what traces human civilization would leave behind and how future scientists might find evidence of our existence.
The researchers looked at the likely geological fingerprint of the Anthropocene—a term used by many researchers to denote the current geological age in which human activity has been the primary influence on the climate and environment.
While the Anthropocene has not yet been officially classified as a distinct geological era, it is already clear that humans are having an impact on the geological record being laid down today, the authors wrote in the paper.
"We are already a geophysical force, and our presence is being recorded in carbon, oxygen and nitrogen isotopes, extinctions, extra sedimentation, spikes in heavy metals and synthetic chemicals (including plastics)," Schmidt told Newsweek.
The human burning of fossil fuels, for example, is already having an impact on the geological record, despite industrialization only beginning around 300 years ago. What's more, global warming, agriculture and the spread of synthetic pollutants are all making their mark.
So let's imagine that, perhaps, some other species on Earth rose briefly to civilization millions of years ago, would there be any traces of them today, for example, fossils or the remains of buildings?
"Possibly," Schmidt said, "but it might also be that all such traces have been ground to dust and that the only remaining traces are in the more subtle perturbations in geochemistry." In addition, "fossilization is extremely rare and very partial, so evidence could easily have been missed," especially if a civilization had lasted just a few thousand or tens of thousands of years, much like our own.
"We know early Mars and, perhaps, early Venus were more habitable than they are now, and conceivably we will one day drill through the geological sediments there, too," Schmidt said in the statement. "This helps us think about what we should be looking for."
Discuss.
I read another article on this subject suggesting the most likely place to find evidence of past civilizations would actually be on the moon or in Earth's orbit, assuming the civilization made it to space before going extinct.
I feel like Tim's response will be a bit more positive. :)
It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?
Quote from: mongers on February 15, 2019, 02:19:14 PM
It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?
This.
Read about this a while ago, and it's an interesting hypothetical/brain exercise as to what long term traces an advanced civilization would leave behind. Whereas in sci-fi you often have remnants of civilization that are well preserved hundreds of thousands and sometimes millions of years later.
Battlestar Galactica
I'm with mongers. Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now. Did the Silurians never advance past the technology of wood-working?
Quote from: Admiral Yi on February 15, 2019, 02:23:57 PM
I'm with mongers. Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now. Did the Silurians never advance past the technology of wood-working?
I should probably have linked multiple articles that are more in-depth about the hypothesis to this thread, but in one of them with a more in-depth writeup about the original paper, it said that in fact plastic would break down over many millions of years, so while there wouldn't be a recognizable plastic bottle there might be odd chemical signatures indicating something unnatural was happening during whatever era this hypothetical civilization existed in.
Quote from: Syt on February 15, 2019, 02:21:29 PM
Read about this a while ago, and it's an interesting hypothetical/brain exercise as to what long term traces an advanced civilization would leave behind. Whereas in sci-fi you often have remnants of civilization that are well preserved hundreds of thousands and sometimes millions of years later.
Yeah. I am not saying "I believe there were past civilizations" in posting the article, but the authors are trying to make the argument that suggesting so isn't a completely laughable idea like I would have thought prior to reading about the hypothesis.
We don't. It's impossible to know.
There's also the theory of ice age human pseduo civilization in areas that have since flooded.
All cool theories alas unlikely.
Quote from: mongers on February 15, 2019, 02:19:14 PM
It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?
But the dinosaurs existed for a ridiculously long period of time - over 100 million years, yet what we know of them is so very little. Many known dinosaur species are known from only a single example found. All of human civilization has only existed for a few thousand years, and our "modern" civilization only 1-200 - a geological blink of an eye.
But yeah, pretty unlikely.
Quote from: Admiral Yi on February 15, 2019, 02:23:57 PM
I'm with mongers. Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now. Did the Silurians never advance past the technology of wood-working?
Plastic bottles are biodegradable. They are estimated last hundreds of years perhaps a few thousand in the right environment, but not billions. If you were to look for a civilization that existed hundreds of millions of year ago your best bet would be checking layers of sedentary rock. Human civilization produces a lot of weird chemicals that escape into the atmosphere. Those will eventually settle to the ground, become part of the sediment and turn into stone.
EDIT: Sedentary rock is like Sedimentary rock but lazier.
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
65 million years later? :hmm:
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
Anyway, the dudes who authored the paper weren't pulling a Timmay; the discussion was initially about "if humans went extinct and aliens showed up in 100 million years could they tell we were ever here". When they realized how difficult it would probably be for them to do so on such a massive timescale the second question came up of as an aside of "how do we know we've been the only civilization on earth?"
Quote from: Caliga on February 15, 2019, 04:33:05 PM
Anyway, the dudes who authored the paper weren't pulling a Timmay; the discussion was initially about "if humans went extinct and aliens showed up in 100 million years could they tell we were ever here".
Twinkies
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
As Mongers pointed out, we have a pretty good fossil record with no signs of a civilization.
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
Yet many rocks are completely unaffected, retaining even delicate fossils. Some areas (particularly, in the middle of continents) remain relatively unaffected, which is why we can even find some remains dating back hundreds of millions of years.
If we disappear from the earth, no doubt some of our works would disappear due to geological forces. But, of a certainty, not *all* of them. Our highways and railway cuttings crisscross whole continents. No known geological force would get rid of *all* cuttings we have made straight through bedrock; civilized agency would, I think, be obvious when such things are spotted.
Quote from: Caliga on February 15, 2019, 04:33:05 PM
Anyway, the dudes who authored the paper weren't pulling a Timmay; the discussion was initially about "if humans went extinct and aliens showed up in 100 million years could they tell we were ever here". When they realized how difficult it would probably be for them to do so on such a massive timescale the second question came up of as an aside of "how do we know we've been the only civilization on earth?"
The answer, though, is that the aliens likely could, and probably without even landing: find a straight line cut through (say) the Canadian Shield, as many are (railways and highways), and they would know.
Quote from: crazy canuck on February 15, 2019, 04:43:49 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
As Mongers pointed out, we have a pretty good fossil record with no signs of a civilization.
As I pointed out, we don't have a very good fossil record. Take a dinosaur like therizinosaurus - it's kind of famous because of it's extremely long claws, but it's only known from a couple of partial fossil remains - we don't even know what kind of head it had.
And the dinosaurs existed for over one hundred million years - lots of time to leave fossils. Human civilization has been around for what - 5,000 years? And advanced technology only for 100-200 years.
I agree it's extremely unlikely, but the concept isn't quite so insane as you might think.
Quote from: Barrister on February 15, 2019, 05:01:49 PM
Quote from: crazy canuck on February 15, 2019, 04:43:49 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
As Mongers pointed out, we have a pretty good fossil record with no signs of a civilization.
As I pointed out, we don't have a very good fossil record. Take a dinosaur like therizinosaurus - it's kind of famous because of it's extremely long claws, but it's only known from a couple of partial fossil remains - we don't even know what kind of head it had.
And the dinosaurs existed for over one hundred million years - lots of time to leave fossils. Human civilization has been around for what - 5,000 years? And advanced technology only for 100-200 years.
I agree it's extremely unlikely, but the concept isn't quite so insane as you might think.
On the other hand, the dinos were around a lot longer, but were probably not nearly as numerous as we are, AND had not artifical impact on their environment.
I think one argument against is that we seem to have a pretty decent, broad strokes sort of idea on how human level intelligence evolved throughout earths history. To imagine another intelligent civilization, don't we have to image some kind of offshoot from the eveolutionary tree that advanced MUCH faster than we think to intelligence, then died out...and we cannot see that in the evolutionary record? Genuine question here.
Quote from: Malthus on February 15, 2019, 04:56:08 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
Yet many rocks are completely unaffected, retaining even delicate fossils. Some areas (particularly, in the middle of continents) remain relatively unaffected, which is why we can even find some remains dating back hundreds of millions of years.
If we disappear from the earth, no doubt some of our works would disappear due to geological forces. But, of a certainty, not *all* of them. Our highways and railway cuttings crisscross whole continents. No known geological force would get rid of *all* cuttings we have made straight through bedrock; civilized agency would, I think, be obvious when such things are spotted.
You're just missing how long a time frame you're talking about.
The Canadian shield is billion year old rocks. But they haven't just been sitting there unaltered for a billion years. They were covered up with new rock layers, then those rock layers eroded away leaving us with the Canadian shield.
In 50 million years the Canadian shield could be covered up with entire new geologic formations, or alternatively it could be uplifted and the shield would be eroded further down.
Heck you don't even have to go that far out - another round of continental glaciation would be enough to remove all trace of human civilization anywhere glaciers would cover, and that would take orders of magnitude less time.
I remember doing field work in northern manitoba the summer before law school with Manitoba Energy & Mines. The particular formation we were working on, for some reason the geologist had commented that this was probably the base of mountain at one point. Of course there was no mountain there now...
Quote from: Berkut on February 15, 2019, 05:05:55 PM
On the other hand, the dinos were around a lot longer, but were probably not nearly as numerous as we are, AND had not artifical impact on their environment.
I think one argument against is that we seem to have a pretty decent, broad strokes sort of idea on how human level intelligence evolved throughout earths history. To imagine another intelligent civilization, don't we have to image some kind of offshoot from the eveolutionary tree that advanced MUCH faster than we think to intelligence, then died out...and we cannot see that in the evolutionary record? Genuine question here.
Well homo sapiens first showed up on the scene 300,000 years ago, and homo erectus about 1.5 million years ago. That's pretty fast. And despite that being very recent geologically speaking we don't have a great fossil record of human evolution either - missing links and all.
So we're hypothesizing a species that evolved and existed for a 1 or 2 million year period. For all but the last few thousand years of that period though it could easily have been restricted to a fairly small geographic area, much like early humans in east Africa. It could be that any fossils from that period have been eroded away, or alternatively still exist but buried under 100s of metres of rock.
Quote from: Barrister on February 15, 2019, 05:09:22 PM
Quote from: Malthus on February 15, 2019, 04:56:08 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
Yet many rocks are completely unaffected, retaining even delicate fossils. Some areas (particularly, in the middle of continents) remain relatively unaffected, which is why we can even find some remains dating back hundreds of millions of years.
If we disappear from the earth, no doubt some of our works would disappear due to geological forces. But, of a certainty, not *all* of them. Our highways and railway cuttings crisscross whole continents. No known geological force would get rid of *all* cuttings we have made straight through bedrock; civilized agency would, I think, be obvious when such things are spotted.
You're just missing how long a time frame you're talking about.
The Canadian shield is billion year old rocks. But they haven't just been sitting there unaltered for a billion years. They were covered up with new rock layers, then those rock layers eroded away leaving us with the Canadian shield.
In 50 million years the Canadian shield could be covered up with entire new geologic formations, or alternatively it could be uplifted and the shield would be eroded further down.
Heck you don't even have to go that far out - another round of continental glaciation would be enough to remove all trace of human civilization anywhere glaciers would cover, and that would take orders of magnitude less time.
I remember doing field work in northern manitoba the summer before law school with Manitoba Energy & Mines. The particular formation we were working on, for some reason the geologist had commented that this was probably the base of mountain at one point. Of course there was no mountain there now...
The point you are missing is that, while this is no doubt true of *some places* which will be altered beyond recognition, it is not true of *every place*. Yet human activity spans most of the globe.
99% of that activity could be wiped out by glaciation or whatever, but all it takes is *one* mine in solid rock, *one* railway cutting through solid rock to visibly survive *anywhere on Earth*, and your hypothetical aliens would *know for sure* that some civilization had once existed.
The Appalachian mountains, for example are very old - 480 million years old - they were around when the dinosaurs were, and they are still around now, though much uplifted and eroded.
Even better, note how ancient survivals are found in Australia:
https://journals.openedition.org/geomorphologie/9166
QuoteBut for almost a century, in Australia and elsewhere, there have been reports and claims of substantial landscape elements that are of much greater antiquity, and that, indeed, date from the Mesozoic (Twidale, 2007). They are not exhumed though such forms, which are of various ages, are recorded in the landscape and in the literature. Many are of subCretaceous date, but a few are as old as Archaean. The very old surfaces considered here are of etch type. Even duricrust-capped surfaces lack an A-horizon. Their character was concisely expressed by E.S. Hills when discussing the high plains of eastern Victoria: 'While these high surfaces of low relief clearly represent preserved relics of old surfaces which have escaped deep dissection, they have naturally suffered some reduction and modification in detail during the long periods of time to which they have been exposed to weathering and erosion, but this is relatively minor.' (Hills, 1975, p. 300).
Quote from: Barrister on February 15, 2019, 05:01:49 PM
Quote from: crazy canuck on February 15, 2019, 04:43:49 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
As Mongers pointed out, we have a pretty good fossil record with no signs of a civilization.
As I pointed out, we don't have a very good fossil record. Take a dinosaur like therizinosaurus - it's kind of famous because of it's extremely long claws, but it's only known from a couple of partial fossil remains - we don't even know what kind of head it had.
And the dinosaurs existed for over one hundred million years - lots of time to leave fossils. Human civilization has been around for what - 5,000 years? And advanced technology only for 100-200 years.
I agree it's extremely unlikely, but the concept isn't quite so insane as you might think.
Your argument that there may be some specific fossils missing from the fossil record does not address the fact that there are no signs in any of the fossil record we do have. For the theory to work there would have to be some as yet unexplored fossil lawyer in which the civilization is waiting to be discovered. Not some detail within well explored fossil layers.
To put it another way, there has been absolutely no signs of civilization in any of the context in which the numerous fossils we have were found.
Quote from: Malthus on February 15, 2019, 05:34:39 PM
The point you are missing is that, while this is no doubt true of *some places* which will be altered beyond recognition, it is not true of *every place*. Yet human activity spans most of the globe.
99% of that activity could be wiped out by glaciation or whatever, but all it takes is *one* mine in solid rock, *one* railway cutting through solid rock to visibly survive *anywhere on Earth*, and your hypothetical aliens would *know for sure* that some civilization had once existed.
The Appalachian mountains, for example are very old - 480 million years old - they were around when the dinosaurs were, and they are still around now, though much uplifted and eroded.
https://geomaps.wr.usgs.gov/parks/province/appalach.html
The appalachians are indeed very old. But not really that old. From your link:
QuoteDuring the middle Ordovician Period (about 440-480 million years ago), a change in plate motions set the stage for the first Paleozoic mountain building event (Taconic orogeny) in North America. The once quiet, Appalachian passive margin changed to a very active plate boundary when a neighboring oceanic plate, the Iapetus, collided with and began sinking beneath the North American craton. With the birth of this new subduction zone, the early Appalachians were born.
Along the continental margin, volcanoes grew, coincident with the initiation of subduction. Thrust faulting uplifted and warped older sedimentary rock laid down on the passive margin. As mountains rose, erosion began to wear them down. Streams carried rock debris downslope to be deposited in nearby lowlands.
Folded rocks in the Appalachians
NASA image of the Appalachian Valley and Ridge province. These rock layers were folded during the series of continental collisions that formed the Appalachians during the Paleozoic Era. Much more recent (Cenozoic) uplift and erosion produced the landscape we see today.
So what happened 480 million years ago was that there began an active plate margin. The Appalachians we see today though have been formed in the Cenozoic - the era we are in now, and the one that followed the dinosaurs.
So while there was mountain building in the past in the region, which formed some of the intense folding and metamorphosis we see in the rock layers, the Appalachian mountains were uplifted, and then eroded into the very old mountains we see today, all within the last 65 million years.
The entire surface of the earth would be turned over in 50 million years. Nothing on the surface would be remaining as it is now. 100 or 1000 years? For sure. 50 million - nope.
The problem with the Silurian hypothesis is surely something from this ancient race would have been fossilized - buried under rock and preserved. It's not impossible that such fossils exist and just haven't been found, but pretty darn unlikely.
The surface will be different, but that means areas that get covered up will sometimes be pushed back to the surface. That's how we find ancient fossils. You probably wouldn't be able to see it from space but you would be able to find uncovered layers that include modern roads. Still I like my idea of looking sedimentary rock. You can find that relatively easily. You can find the boundary that that separate the Cretaceous and the Paleogene all over the world. And in that boundary you can find you can find anomalous elements like iridium. That's how we know a big space rock crashed into the Earth 65 million years ago.
Quote from: crazy canuck on February 15, 2019, 05:50:54 PM
Quote from: Barrister on February 15, 2019, 05:01:49 PM
Quote from: crazy canuck on February 15, 2019, 04:43:49 PM
Quote from: Barrister on February 15, 2019, 04:19:55 PM
Quote from: Malthus on February 15, 2019, 03:47:12 PM
If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.
The time scale involved is enough for substantial continental drift. Entire mountain ranges can form, or be eroded into nothingness.
As Mongers pointed out, we have a pretty good fossil record with no signs of a civilization.
As I pointed out, we don't have a very good fossil record. Take a dinosaur like therizinosaurus - it's kind of famous because of it's extremely long claws, but it's only known from a couple of partial fossil remains - we don't even know what kind of head it had.
And the dinosaurs existed for over one hundred million years - lots of time to leave fossils. Human civilization has been around for what - 5,000 years? And advanced technology only for 100-200 years.
I agree it's extremely unlikely, but the concept isn't quite so insane as you might think.
Your argument that there may be some specific fossils missing from the fossil record does not address the fact that there are no signs in any of the fossil record we do have. For the theory to work there would have to be some as yet unexplored fossil lawyer in which the civilization is waiting to be discovered. Not some detail within well explored fossil layers.
To put it another way, there has been absolutely no signs of civilization in any of the context in which the numerous fossils we have were found.
OTOH, I've seen estimates that we only have fossil records of 1% or less of all species that have gone extinct. Of course, most of those would likely be microscopic, but still.
Human history is so incredibly short it may make it difficult to find traces hundreds of millions of years from now (assuming it all ends in a poof in the near term), but the natural history of the world would presumably take a sharp turn--we are likely in a significant mass extinction event as we speak.
I think a more relevant question is not whether an advanced civilization lived some distant time ago, but whether we are grossly underestimating the amount of life in the precambrian.
Something that really hit me about the dramatic changes over geologic time was the statement that a regional mountain (about 2k m) would be around long after we were. While undoubtably true, I began thinking--the mountain gets a ton of hikers--it seems only logical that from erosion it would lose a 1 cm a year at least. That means a meter in a century. At that pace, in just 200k years--not even a blip in geologic time--it would be at sea level.
Quote from: alfred russel on February 15, 2019, 08:18:38 PM
Something that really hit me about the dramatic changes over geologic time was the statement that a regional mountain (about 2k m) would be around long after we were. While undoubtably true, I began thinking--the mountain gets a ton of hikers--it seems only logical that from erosion it would lose a 1 cm a year at least. That means a meter in a century. At that pace, in just 200k years--not even a blip in geologic time--it would be at sea level.
A possible flaw in your argument, I guess hikers aim for the top of the mountain, so as they wear it away 1cm at a time, then increasing numbers will have to be spread out over the consequent larger area revealed, so as to continue that rate of erosion.
By the time the mountain is down to half height, there's now an awfully big area that needs to be eroded by a rather large number of not too imaginative hikers.
Quote from: mongers on February 15, 2019, 08:24:10 PM
Quote from: alfred russel on February 15, 2019, 08:18:38 PM
Something that really hit me about the dramatic changes over geologic time was the statement that a regional mountain (about 2k m) would be around long after we were. While undoubtably true, I began thinking--the mountain gets a ton of hikers--it seems only logical that from erosion it would lose a 1 cm a year at least. That means a meter in a century. At that pace, in just 200k years--not even a blip in geologic time--it would be at sea level.
A possible flaw in your argument, I guess hikers aim for the top of the mountain, so as they wear it away 1cm at a time, then increasing numbers will have to be spread out over the consequent larger area revealed, so as to continue that rate of erosion.
By the time the mountain is down to half height, there's now an awfully big area that needs to be eroded by a rather large number of not too imaginative hikers.
Definitely--at a certain point we are talking about eroding basically the eastern seaboard of North America to sea level.
My point was more that 1 cm of activity may not seem like much in a year, but over geologic time that is race car fast.
I think you are mistaken with the idea of hikers eroding a mountain. To lower mountains you'd need to remove millions of cubic meters every year.
Quote from: Razgovory on February 15, 2019, 08:41:02 PM
I think you are mistaken with the idea of hikers eroding a mountain. To lower mountains you'd need to remove millions of cubic meters every year.
I think AR is just revealing more of his Buddhism.
Quote from: Razgovory on February 15, 2019, 08:41:02 PM
I think you are mistaken with the idea of hikers eroding a mountain. To lower mountains you'd need to remove millions of cubic meters every year.
You don't just have erosion at the very summit...you have erosion all the way up and down, plus reduced vegetation leading to more runoff.
Heck, my guide on the matterhorn is building a fireplace for his house with stones from the matterhorn--every time he goes he brings back a stone. There are a lot of stones on the matterhorn, but if people kept doing that for 2 or 3 million years? It would make a difference.
Quote from: alfred russel on February 16, 2019, 07:01:56 AM
Quote from: Razgovory on February 15, 2019, 08:41:02 PM
I think you are mistaken with the idea of hikers eroding a mountain. To lower mountains you'd need to remove millions of cubic meters every year.
You don't just have erosion at the very summit...you have erosion all the way up and down, plus reduced vegetation leading to more runoff.
Heck, my guide on the matterhorn is building a fireplace for his house with stones from the matterhorn--every time he goes he brings back a stone. There are a lot of stones on the matterhorn, but if people kept doing that for 2 or 3 million years? It would make a difference.
I'm not sure about the Alps, but some mountain ranges (the Andes for example) are still growing, which would probably more than offset anything hikers or climbers can do.
I see why cdm accused everyone of having aspergers. My point was not that hikers are going to erode away the mountains. My point was that even what seems to us to be very modest rates of change--on a geologic time scale--may be operating at a break neck pace.
The problem is that you made your point very poorly, not with our reading comprehension.
Quote from: dps on February 16, 2019, 08:02:44 AM
The problem is that you made your point very poorly, not with our reading comprehension.
Marti doesn't post here any more, so AR has taken up the mantle of making really shitty analogies. It's a tough job, but he is a tough man - tough enough to insult everyone who points out shitty analogies when they see them.
Quote from: alfred russel on February 16, 2019, 07:14:23 AM
I see why cdm accused everyone of having aspergers. My point was not that hikers are going to erode away the mountains. My point was that even what seems to us to be very modest rates of change--on a geologic time scale--may be operating at a break neck pace.
It did read like you attributed erosion solely to hikers walking the mountain down.
Read about the Silurian Hypothesis when it arrived on the internets a few weeks ago and thought it was delightfully nutty. More stoner science than actual science I thought, but fun none the less.
Made me immediately think of Harry Harrisons books with the intelligent reptile civilization, which are great fun as well.
https://en.wikipedia.org/wiki/West_of_Eden (https://en.wikipedia.org/wiki/West_of_Eden)
The Julian May books about the discontents who get sent on a one way trip back in time only to discover that the the Pleiocene Earth is hosting a crashed alien spaceship who have enslaved our hominid ancestors also springs to mind. :)
https://en.wikipedia.org/wiki/Saga_of_Pliocene_Exile (https://en.wikipedia.org/wiki/Saga_of_Pliocene_Exile)
Interesting, and this idea has crossed my mind before but as others point out, how we haven't found any traces of a prior civilization yet we've found dinosaur artifacts. The article doesn't point out why that could be, as I assume fossils of bones would have been found. Or if they were advanced far enough other items that would endure over a long time such as metallic objects could be found.
The other side of things could be that we keep finding new types of dinosaurs and pre-human remains so there's always a lot more to discover.
I find it extremely unlikely that an advanced civilization can leave absolutely no trace whatsoever.
Quote from: Barrister on February 15, 2019, 05:54:40 PM
Quote from: Malthus on February 15, 2019, 05:34:39 PM
The point you are missing is that, while this is no doubt true of *some places* which will be altered beyond recognition, it is not true of *every place*. Yet human activity spans most of the globe.
99% of that activity could be wiped out by glaciation or whatever, but all it takes is *one* mine in solid rock, *one* railway cutting through solid rock to visibly survive *anywhere on Earth*, and your hypothetical aliens would *know for sure* that some civilization had once existed.
The Appalachian mountains, for example are very old - 480 million years old - they were around when the dinosaurs were, and they are still around now, though much uplifted and eroded.
https://geomaps.wr.usgs.gov/parks/province/appalach.html
The appalachians are indeed very old. But not really that old. From your link:
QuoteDuring the middle Ordovician Period (about 440-480 million years ago), a change in plate motions set the stage for the first Paleozoic mountain building event (Taconic orogeny) in North America. The once quiet, Appalachian passive margin changed to a very active plate boundary when a neighboring oceanic plate, the Iapetus, collided with and began sinking beneath the North American craton. With the birth of this new subduction zone, the early Appalachians were born.
Along the continental margin, volcanoes grew, coincident with the initiation of subduction. Thrust faulting uplifted and warped older sedimentary rock laid down on the passive margin. As mountains rose, erosion began to wear them down. Streams carried rock debris downslope to be deposited in nearby lowlands.
Folded rocks in the Appalachians
NASA image of the Appalachian Valley and Ridge province. These rock layers were folded during the series of continental collisions that formed the Appalachians during the Paleozoic Era. Much more recent (Cenozoic) uplift and erosion produced the landscape we see today.
So what happened 480 million years ago was that there began an active plate margin. The Appalachians we see today though have been formed in the Cenozoic - the era we are in now, and the one that followed the dinosaurs.
So while there was mountain building in the past in the region, which formed some of the intense folding and metamorphosis we see in the rock layers, the Appalachian mountains were uplifted, and then eroded into the very old mountains we see today, all within the last 65 million years.
The entire surface of the earth would be turned over in 50 million years. Nothing on the surface would be remaining as it is now. 100 or 1000 years? For sure. 50 million - nope.
The problem with the Silurian hypothesis is surely something from this ancient race would have been fossilized - buried under rock and preserved. It's not impossible that such fossils exist and just haven't been found, but pretty darn unlikely.
You didn't address the second link, which strongly raises the notion that "The entire surface of the earth would be turned over in 50 million years. Nothing on the surface would be remaining as it is now" is incorrect, at least for some landscapes.
https://journals.openedition.org/geomorphologie/9166
All it takes is *some* survivals to make a civilized past obvious.
No-one doubts that there is a huge turnover in landscape due to geologic forces. What is in question, that you have asserted as fact, is whether this turnover is so total and complete as to erase all traces of man-made landscape modification.
Consider that in the middle east, entire hills, known as "tels", are constructed out of human garbage; much of that long-lasting (worked stone, pottery sherds). These where made by relatively small-scale civilizations ...
More of the same:
https://www.researchgate.net/publication/240798767_The_Enigma_of_Survival_Problems_Posed_by_Very_Old_Paleosurfaces
"Ancient Landscapes are also termed palaeosurfaces (e.g. Twidale 2000 Twidale , 2003 ). Some have experienced extremely prolonged sub-aerial exposure and are pre-Cenozoic. ..."
Yet more:
QuoteMore surprisingly, perhaps, landscapes of great antiquity that have not been preserved by burial and then resurrected, but which have apparently been exposed to the elements since inception, loom large in the landscape in several parts of the world. Michel
(1978) and Demangeot (1978) have recorded lateritised land surfaces of later Mesozoic age in W Africa and S India respectively, and King (1942, 1950) long ago presented cogent arguments pointing to the later Mesozoic age of the high plains and plateaux bounded by the great Drakensberg Escarpment in S Africa. Similar discoveries have been made in Australia ...
https://link.springer.com/article/10.1007/BF00214393
This means that, in various places across the world, surface landscapes have allegedly survived since the time of the dinosaurs.
The problem with the 'the entire surface of the world has been replaced, so nothing can have survived from then until now' is that it is based on an outdated notion of the uniformity of impact of geological forces. Certainly it is true that most places have been completely changed. However, most is not the same thing as all, and it appears that the weight of scientific evidence is against "all" having been changed.
Thanks for replying to this Malthus!
I suspect though that both of us are going at it with our own biases of past experience: you go back to your archaeology roots talking about middle eastern tels, despite that being insignificant in geologic time frame. And I probably look too much at my own background, which was indeed in geology (but totally unconcerned with any notion of looking for proof of civilizations).
I don't think we're going to be able to definitively solve this one though. I would note that of your three links, two are paywalled, with only a brief synopsis available for public viewing. The one that can be viewed (your first link) isn't any original research, but rather an analysis and summary of past research. It also is quite upfront that this is quite an extraordinary and controversial claim that is being made: the title of the entire article is "The ancient landscapes concept: 'Important if true'".
So just two thoughts:
Even if true, such ancient landscapes are quite rare on the earth - limited to areas with little tectonic activity, unreactive and exposed bedrock, little exposure to water. Indeed such landscapes might be limited to Australia alone. As such, the fact we don't see any proof of prehistoric civilizations in some of the most inhospitable places on earth doesn't really tell us very much.
Second, it's still a matter of timeframe. I was either using a timeframe of 50 million years, or going as far back as the start of the cretaceous period, 65 million years, as that seemed like a pretty far back period of time. But the title of the thread itself is the Silurian Hypothesis - and the Silurian period is a whole order of magnitude further back, starting 444 million years ago, and ending 419 million years ago (and predates even the dinosaurs). Even your "ancient landscapes" don't date that far back.
So I'm going to stick with my conclusion so far: prehistoric civilizations are extremely unlikely, but can not be entirely ruled out.
Quote from: Barrister on February 21, 2019, 11:56:16 AM
Thanks for replying to this Malthus!
I suspect though that both of us are going at it with our own biases of past experience: you go back to your archaeology roots talking about middle eastern tels, despite that being insignificant in geologic time frame. And I probably look too much at my own background, which was indeed in geology (but totally unconcerned with any notion of looking for proof of civilizations).
I don't think we're going to be able to definitively solve this one though. I would note that of your three links, two are paywalled, with only a brief synopsis available for public viewing. The one that can be viewed (your first link) isn't any original research, but rather an analysis and summary of past research. It also is quite upfront that this is quite an extraordinary and controversial claim that is being made: the title of the entire article is "The ancient landscapes concept: 'Important if true'".
So just two thoughts:
Even if true, such ancient landscapes are quite rare on the earth - limited to areas with little tectonic activity, unreactive and exposed bedrock, little exposure to water. Indeed such landscapes might be limited to Australia alone. As such, the fact we don't see any proof of prehistoric civilizations in some of the most inhospitable places on earth doesn't really tell us very much.
Second, it's still a matter of timeframe. I was either using a timeframe of 50 million years, or going as far back as the start of the cretaceous period, 65 million years, as that seemed like a pretty far back period of time. But the title of the thread itself is the Silurian Hypothesis - and the Silurian period is a whole order of magnitude further back, starting 444 million years ago, and ending 419 million years ago (and predates even the dinosaurs). Even your "ancient landscapes" don't date that far back.
So I'm going to stick with my conclusion so far: prehistoric civilizations are extremely unlikely, but can not be entirely ruled out.
I'm as hard on Australians as the next guy, but I still think of them as basically "civilized". :D If humans can live on places like Australia, so too can our hypothetical pre-human civilizations. Indeed, humans are found in all sorts of horrible places, like the Atacama Desert:
https://en.wikipedia.org/wiki/Salta%E2%80%93Antofagasta_railway
Certainly landscapes such as those mentioned in the articles are not the common run, but allegedly (according to the last link) they exist in several places ... but really, all you need is
some.
The issue isn't going to be whether how
much survives, but whether
anything survives. Finding even
one obviously man-made relic (say, a straight cutting through bedrock) would give the game away.
Sure, if the point in time is far back enough, there would be no evidence surviving ... but that also makes any notion of intelligent beings increasingly absurd. Intelligent dinosaurs is much more possible than intelligent trilobites. :D If intelligent dinosaurs created a civilization like ours, we'd certainly know about that; not so much if intelligent trilobites of the early Silurian created one - but that isn't very likely.
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
If there was, it wasn't terrestrial in origin. 2.5 billion years ago, the most advanced life on Earth was probably a multicellular cyanobacterium:
http://www.bbc.com/earth/story/20150701-the-origin-of-the-air-we-breathe
Edit: holy simulpost Batman! :lol:
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
Earth being seeded from elsewhere is quite a different awesome theory.
I also recall seeing a theory however that calculated due to the age of the universe we should be towards the earlier side of advanced life.
Quote from: Tyr on February 21, 2019, 03:01:53 PM
Earth being seeded from elsewhere is quite a different awesome theory.
I also recall seeing a theory however that calculated due to the age of the universe we should be towards the earlier side of advanced life.
Maybe we are going to seed them!
Quote from: Valmy on February 21, 2019, 03:05:28 PM
Quote from: Tyr on February 21, 2019, 03:01:53 PM
Earth being seeded from elsewhere is quite a different awesome theory.
I also recall seeing a theory however that calculated due to the age of the universe we should be towards the earlier side of advanced life.
Maybe we are going to seed them!
The hope of every R34 science fiction artist out there ... ;)
Quote from: Tyr on February 21, 2019, 03:01:53 PM
I also recall seeing a theory however that calculated due to the age of the universe we should be towards the earlier side of advanced life.
Right, I've read that as well, in the context of "why haven't we heard from other civilizations?" (we're the first ones)
Quote from: Valmy on February 21, 2019, 03:05:28 PM
Quote from: Tyr on February 21, 2019, 03:01:53 PM
Earth being seeded from elsewhere is quite a different awesome theory.
I also recall seeing a theory however that calculated due to the age of the universe we should be towards the earlier side of advanced life.
Maybe we are going to seed them!
That's my religious theory. That humans are life-sperm.
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
You and Malthus are both completely missing the point....How can we be sure there wasn't multicellular life on earth 2.5 billion years ago?
I didn't pick that date at random. That is the date that atmospheric oxygen basically exploded.
Quote from: alfred russel on February 21, 2019, 04:30:58 PM
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
You and Malthus are both completely missing the point....How can we be sure there wasn't multicellular life on earth 2.5 billion years ago?
I didn't pick that date at random. That is the date that atmospheric oxygen basically exploded.
Well for starters I was wrong - there was multicellular life at 2.5 billion years ago, but it was multicellular cyanobacteria. There was no even remotely complex multicellular life.
When you're going that far back there are never any guarantees, but we can say there is no evidence in the fossil record of any form of complex life in the precambrian era.
Quote from: alfred russel on February 21, 2019, 04:30:58 PM
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
You and Malthus are both completely missing the point....How can we be sure there wasn't multicellular life on earth 2.5 billion years ago?
I didn't pick that date at random. That is the date that atmospheric oxygen basically exploded.
Because there is no evidence for anything very complex back then, and lots of evidence for a slow evolution towards greater complexity since then? Oxygen exploded it is true, but there was nothing, as far as we know, more complicated than bacteria 2.5 BYA. Things as complex as a worm only developed much later. Nearly two billion years later.
https://www.newscientist.com/article/2146935-tiny-worm-burrows-may-reveal-when-first-complex-animals-evolved/
Unless we are missing a whole evolutionary history in the fossil record, which seems very unlikely.
About the only point in favor of this hypothesis is the Great Unconformity (https://en.wikipedia.org/wiki/Great_Unconformity), where rocks for a big chunk of time are just gone. The problem is that there isn't any obvious discontinuity in the progression of life before or after this missing data, so we are back to some lifeforms that not only left no presence themselves but also left no mark on anything that came after.
Quote from: Barrister on February 21, 2019, 04:39:12 PM
Well for starters I was wrong - there was multicellular life at 2.5 billion years ago, but it was multicellular cyanobacteria. There was no even remotely complex multicellular life.
When you're going that far back there are never any guarantees, but we can say there is no evidence in the fossil record of any form of complex life in the precambrian era.
BB--both you and Malthus are missing the point...this thread is dedicated to the idea we may be missing a major civilization 400m years ago. If that is possible, then why wouldn't we be missing something 2.5 billion years ago? At least Malthus is consistent in saying "no" to both theories.
The fossil record in that era is not especially complete, especially considering that there is no guarantee that they would easily be preserved (such as bones). 100 million years is a very long time in evolutionary history, and the environment radically changed in the period, which could explain a truly mass extinction leaving few traces.
I'm not saying this happened, just trying to expand the scope of what we could be wrong about.
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
Aliens! :o
Quote from: Barrister on February 21, 2019, 04:39:12 PM
Quote from: alfred russel on February 21, 2019, 04:30:58 PM
Quote from: Barrister on February 21, 2019, 02:59:52 PM
Quote from: alfred russel on February 21, 2019, 02:55:01 PM
Also the earth is 4.5 billion years old. I know the proposal is for a more recent period, but what if there was an ancient civilization 2.5 billion years ago? That makes the challenge doubly difficult: 1) so much more time has past, and 2) the earth's environment was likely different enough to lead to an ancient civilization quite different from our own (and hence we may be oblivious to some signs).
Problem is 2.5 billion years ago there wasn't even any multi-cellular life on earth, and I'm not even sure there was much atmospheric oxygen. Any civilization that long ago would have had to come from somewhere else.
You and Malthus are both completely missing the point....How can we be sure there wasn't multicellular life on earth 2.5 billion years ago?
I didn't pick that date at random. That is the date that atmospheric oxygen basically exploded.
Well for starters I was wrong - there was multicellular life at 2.5 billion years ago, but it was multicellular cyanobacteria. There was no even remotely complex multicellular life.
When you're going that far back there are never any guarantees, but we can say there is no evidence in the fossil record of any form of complex life in the precambrian era.
Carbon based multicellular life.
[ur] https://www.ancient-origins.net/news-history-archaeology/ancient-underwater-ruins-atlantis-0011008 [/url]
QuoteThe Latest Discovery of the Legendary City of Atlantis
Scientists at Merlin Burrows are celebrating having discovered the most important archaeological finding of all time, exactly where Plato said it was, "in front of "the pillars of Heracles." According to a report in The Daily Mail , Atlantis, is located "north of the city of Cadiz, Andalucía, centered around the Doñana National Park," which the Merlin Burrows historians "believe was once a vast inland sea."
Even though a Live Science feature in February applied clear scientific logic to establish that "Plato's lost city of Atlantis was never lost; it is where it always was: in Plato's books," using satellite investigation techniques, aerial photography and ground observations, the Merlin Burrows experts believe they have "found all the features of Atlantis Plato described" and that "that south and north of the park there is further evidence of the ancient civilization, with 15 other settlements dotted along the coastline." What is more, they have found evidence that the city was destroyed by a tsunami, again, just like Plato said happened to Atlantis.
Showing utter defiance in the face of what will amount to a towering wall of rock hard skepticism, Maritime historian Tim Akers, head of research at Merlin Burrows, went so far as to tell reporters that his team "have collected samples which have been scientifically tested in a lab in Modena, Italy, which is used to test ancient Roman finds. The results of the tests prove the age of the finds are older than Roman or Greek, and that they were more advanced."
Plato wrote that the harbor wall was "50 stadia" (five-and-a-half miles) in length and the satellite images show what Merlin Burrows claim is "evidence still visible today of sand dunes where this massive wall was destroyed by a huge influx of water" measuring an incredible 75 meters (245 ft) thick. The team also claim, "Laboratory analysis' of material recovered from Spain showed evidence of a type of cement not seen before, as well as ancient advanced metallurgy." "A greenish blue patina has been found covering some of the ruins which tests have shown is an ancient combination of metals. Plato describes in detail a patina on the buildings and structures of the cities and temples making up this complex," Akers added.
More supposed discovery of Plato's Atlantis, an advanced civ thousands of years old. As usual though, much skepticism ensues.
How old are we talking about here? Like Egypt Old Kingdom old? Neolithic old?
The Ancient Origins site says scientists claim about 10,000 years old. Here's another part of the story. This is the first time I've seen this website. A while ago I had read about findings of pillars and structures found underwater which baffled scientists, so I searched on those words and found this site.
QuoteThe coast of southern Spain is an archaeological wonderland with thousands of ruins from ancient Roman and Greek cultures, but hidden among these crumbling stones, scientists from a private satellite imaging firm claim to have found evidence of "a lost city with huge harbour walls", which they believe was built by the legendary "Atlanteans," over 10,000 years ago – the legendary city of Atlantis.
In 400 BC Greek philosopher Plato wrote not the history of, but the ' story' of Atlantis in his dialogues, the Timaeus and the Critias, written about 330 BC. Describing the catastrophic collapse of an island dwelling maritime civilization that had used high technology 9,000 years before Plato's own lifetime, the capital city of Atlantis was described as having "huge entrance pillars, a temple to the god Poseidon, massive circular pieces of habitable land, and all this protected by 'enormous harbour walls'.
Despite any proven truth to the story, countless Atlantis "experts" have all successfully located the famous lost continent in places such as: the Atlantic Ocean, Antarctica, Bolivia, Turkey, Germany, Malta and the Caribbean. Only two months ago The Express published a similar article claiming a researcher had "finally discovered Atlantis" in the Sahara. Plato, however, was crystal clear about where Atlantis was located: "in front of the mouth which you Greeks call, as you say, 'the pillars of Heracles,' i.e. "The pillars of Hercules" or the Straits of Gibraltar, at the mouth of the Mediterranean.
Santorini (ancient Thera) is almost certainly what Plato's sources were describing, from everything I have seen. Destroyed in a volcanic explosion roughly 1500 BCE (the exact date is debatable).
There are numerous "pillars of Hercules" in the ancient Mediterranean.
How did you escape that volcano?
Quote from: grumbler on February 23, 2019, 12:15:42 AM
Santorini (ancient Thera) is almost certainly what Plato's sources were describing, from everything I have seen. Destroyed in a volcanic explosion roughly 1500 BCE (the exact date is debatable).
Agreed, and there seems to be some consensus that it inspired Plato's dialogues. What I never understood is why people presume it was a real place as described in the Kritias/Timaios (IIRC). It seems a bit as if people were looking for the island of Utopia.
I guess isotope changes caused by nuclear technology could be detected long (billions of years) after the civilization was gone.
Quote from: grumbler on February 23, 2019, 12:15:42 AM
Santorini (ancient Thera) is almost certainly what Plato's sources were describing, from everything I have seen. Destroyed in a volcanic explosion roughly 1500 BCE (the exact date is debatable).
There are numerous "pillars of Hercules" in the ancient Mediterranean.
Yeah, most likely that or the Black Sea deluge theory.
It took billions of years to build up the massive amounts of coal and oil we have found. Removing it from the Earth is not a pretty process. Mountains are ripped apart and giant sinkholes formed. If a civilization reached the stage of 20th century global exploitation of fossil fuels we would know. So any Saurian civilization must have been simpler than that.
Quote from: jimmy olsen on March 02, 2019, 02:07:37 AM
It took billions of years to build up the massive amounts of coal and oil we have found. Removing it from the Earth is not a pretty process. Mountains are ripped apart and giant sinkholes formed. If a civilization reached the stage of 20th century global exploitation of fossil fuels we would know. So any Saurian civilization must have been simpler than that.
No.
The entire point is if you go back far enough mountains ranges are eroded to nothing, and new ones formed in their place. My whole argument with Malthus (who points to some, well, interesting but questionable research) is that the entire landscape of the earth has been completely re-worked since the pre-Cenozoic era.
Quote from: Barrister on March 02, 2019, 02:13:44 AM
Quote from: jimmy olsen on March 02, 2019, 02:07:37 AM
It took billions of years to build up the massive amounts of coal and oil we have found. Removing it from the Earth is not a pretty process. Mountains are ripped apart and giant sinkholes formed. If a civilization reached the stage of 20th century global exploitation of fossil fuels we would know. So any Saurian civilization must have been simpler than that.
No.
The entire point is if you go back far enough mountains ranges are eroded to nothing, and new ones formed in their place. My whole argument with Malthus (who points to some, well, interesting but questionable research) is that the entire landscape of the earth has been completely re-worked since the pre-Cenozoic era.
I would not say "questionable" unless you have something I have not seen that actually counters it! :lol:
Quote from: grumbler on February 23, 2019, 12:15:42 AM
There are numerous "pillars of Hercules" in the ancient Mediterranean.
I only think of the Gibraltar straits when I read "pillars of Hercules" though, i.e the Rock and Ceuta, in North Africa. These are the most likely candidates, though the north African pillar is somewhat disputed.
Quote from: Syt on February 23, 2019, 02:09:38 AM
Quote from: grumbler on February 23, 2019, 12:15:42 AM
Santorini (ancient Thera) is almost certainly what Plato's sources were describing, from everything I have seen. Destroyed in a volcanic explosion roughly 1500 BCE (the exact date is debatable).
Agreed, and there seems to be some consensus that it inspired Plato's dialogues. What I never understood is why people presume it was a real place as described in the Kritias/Timaios (IIRC). It seems a bit as if people were looking for the island of Utopia.
Sometimes, I see people using sarcasm on the internet, in newspapers or in a Facebook comment. Sometimes, I see/hear other people use second degree to hint at something, or to gently mock someone.
And everytime, everytime, I see some people who just don't get it. They take the comment at face value, totally ignoring what is really meant. A journalist recently blogged about how Quebec city was superior to Montreal because it's not a city where a large private promoted would influence public transit and get a building erected even though it does not conform to the urbanism code voted by the city a few years prior. It was obvious he was using second degree/sarcasm to say both cities have similar problems and none should be smug about Montreal's problems with gigantic building disparaging an existing neighbourhood. Yet, he received a fuckton of shit and nasty emails from readers reminding him of some private, questionnable, development projects in Quebec city. He was forced to apologize for using sarcasm the day after.
So, people reading Plato's dialogues and assuming everything is 100% as it is written without any embelishment, translation errors or any kind or any distortion is not surprising at all.Heck, a lot of people believe their sacred books should be read litterally, so why would it be different with a philosopher?
Quote from: Monoriu on February 20, 2019, 09:06:05 PM
I find it extremely unlikely that an advanced civilization can leave absolutely no trace whatsoever.
they had giant floating cities that also served as starship and decided to move far away from here, in another galaxy, once humanoids started to evolve into modern humans and then shed their physical bodies to ascend to an higher plane of existance.
Totally plausible explanation, as good as any.
Quote from: Malthus on March 04, 2019, 10:19:21 AM
Quote from: Barrister on March 02, 2019, 02:13:44 AM
Quote from: jimmy olsen on March 02, 2019, 02:07:37 AM
It took billions of years to build up the massive amounts of coal and oil we have found. Removing it from the Earth is not a pretty process. Mountains are ripped apart and giant sinkholes formed. If a civilization reached the stage of 20th century global exploitation of fossil fuels we would know. So any Saurian civilization must have been simpler than that.
No.
The entire point is if you go back far enough mountains ranges are eroded to nothing, and new ones formed in their place. My whole argument with Malthus (who points to some, well, interesting but questionable research) is that the entire landscape of the earth has been completely re-worked since the pre-Cenozoic era.
I would not say "questionable" unless you have something I have not seen that actually counters it! :lol:
Dude your own links mention the questions! Remember the title "The ancient landscapes concept: 'Important if true'"
It seems prosperous to me that landforms on earth would sit, unchanged by erosion deposition, or other geologic factors, for over a billion years, but I will concede that a few people have suggested that is true.
But you don't get to go around suggesting that these ideas are widely accepted science either!
Quote from: Duque de Bragança on March 04, 2019, 10:30:27 AM
Quote from: grumbler on February 23, 2019, 12:15:42 AM
There are numerous "pillars of Hercules" in the ancient Mediterranean.
I only think of the Gibraltar straits when I read "pillars of Hercules" though, i.e the Rock and Ceuta, in North Africa. These are the most likely candidates, though the north African pillar is somewhat disputed.
That is true for you, but may not have been true for Plato (or his sources).
Quote from: grumbler on March 04, 2019, 07:15:42 PM
Quote from: Duque de Bragança on March 04, 2019, 10:30:27 AM
Quote from: grumbler on February 23, 2019, 12:15:42 AM
There are numerous "pillars of Hercules" in the ancient Mediterranean.
I only think of the Gibraltar straits when I read "pillars of Hercules" though, i.e the Rock and Ceuta, in North Africa. These are the most likely candidates, though the north African pillar is somewhat disputed.
That is true for you, but may not have been true for Plato (or his sources).
Not just me, it is the most commonly accepted view, but granted we'll never be sure for Plato (or his sources), as you point out.
It is an entertaining what-if but unless we talk about a very small population secluded species reaching the earliest stages of Stone Age civilisation, I just can't believe we would not have found traces of them. Not possible.
Quote from: Barrister on March 04, 2019, 05:47:09 PM
Quote from: Malthus on March 04, 2019, 10:19:21 AM
Quote from: Barrister on March 02, 2019, 02:13:44 AM
Quote from: jimmy olsen on March 02, 2019, 02:07:37 AM
It took billions of years to build up the massive amounts of coal and oil we have found. Removing it from the Earth is not a pretty process. Mountains are ripped apart and giant sinkholes formed. If a civilization reached the stage of 20th century global exploitation of fossil fuels we would know. So any Saurian civilization must have been simpler than that.
No.
The entire point is if you go back far enough mountains ranges are eroded to nothing, and new ones formed in their place. My whole argument with Malthus (who points to some, well, interesting but questionable research) is that the entire landscape of the earth has been completely re-worked since the pre-Cenozoic era.
I would not say "questionable" unless you have something I have not seen that actually counters it! :lol:
Dude your own links mention the questions! Remember the title "The ancient landscapes concept: 'Important if true'"
It seems prosperous to me that landforms on earth would sit, unchanged by erosion deposition, or other geologic factors, for over a billion years, but I will concede that a few people have suggested that is true.
But you don't get to go around suggesting that these ideas are widely accepted science either!
Actually reading the articles, though, the "pro" side has cited all sorts of evidence, while the "anti" side can be summed up much like you have done: 'well, we always assumed this wasn't true, it goes against our beliefs, so it sounds unlikely'. :lol:
What is missing, is a reasoned attack on the evidence presented.
Im no geologist, but evidence is the same everywhere: where one side has evidence, and the other is merely skeptical because it goes against their long-held beliefs and "sounds difficult to believe", I side with the evidence until it is disproved with better evidence. That's how science progresses, by demolishing what people *assumed* was true when the actual evidence points the other way ...
Quote from: viper37 on March 04, 2019, 03:14:07 PM
Quote from: Monoriu on February 20, 2019, 09:06:05 PM
I find it extremely unlikely that an advanced civilization can leave absolutely no trace whatsoever.
they had giant floating cities that also served as starship and decided to move far away from here, in another galaxy, once humanoids started to evolve into modern humans and then shed their physical bodies to ascend to an higher plane of existance.
Totally plausible explanation, as good as any.
I like this hypothesis! Give great space to ponder about what if whether one believes it or not. Someday humans on Earth will need to do the same as predictions go the Sun will super nova in three or four billion years.
Then too the Andromeda and Milky Way galaxies are on a collision course which is predicted to occur in a few billion years. Given that humans creating colonies on the Moon and Mars, are concepts being seriously pursued, it may be doable during this century or even by mid century for starters. So if human kind on Earth can survive the endless sitcom replays and unwanted movie sequels, Halloween 1,024k ;) then they hopefully will have developed the tech to move into another safer galaxy.
Quote from: Tamas on March 05, 2019, 08:21:51 AM
It is an entertaining what-if but unless we talk about a very small population secluded species reaching the earliest stages of Stone Age civilisation, I just can't believe we would not have found traces of them. Not possible.
I find it interesting to speculate about "what if the velociraptors reached sentience and had a stone age civilization" but I don't think anyone thinks that with our current level of technology we'd be able to uncover a primitive civilization like that. I think the concession is that we would need a past civilization to have deposited layers of radioactive material in order for there to be any chance at all of detecting them, right?
What about, though, if a previous civilization engaged in climate engineering (intentionally or otherwise)... could we possibly detect that? Like a previous global warming or cooling event not otherwise explained? How could we come to the conclusion it was caused by a civilization... or could we?
Since some birds use tools today, would it be contentious to suggest dinosaurs used them?
As you suggest, the question is whether we could detect a civilization rather than simple tool use. We can easily detect the evidence of the meteor hit that killed off the dinosaurs down to the level of sediment in which the debris is deposited. I am not sure why it would not be possible to detect effects caused by an advanced civilization.
Quote from: Caliga on March 06, 2019, 04:54:13 PM
What about, though, if a previous civilization engaged in climate engineering (intentionally or otherwise)... could we possibly detect that? Like a previous global warming or cooling event not otherwise explained? How could we come to the conclusion it was caused by a civilization... or could we?
Well as I understand it, we have good records through ice cores about ancient temperatures, but such evidence only goes back a few hundred thousand years.
Otherwise, we can infer what ancient climates were like through what kinds of vegetation is preserved in fossils.
Problem is if there was a rapid change in climate, that then lead to the extinction of the Silurian technological society, suich an event likely happened to quickly (geologically speaking) that not enough material would be deposited to ever be able to find.
Quote from: Barrister on March 06, 2019, 05:10:10 PM
Quote from: Caliga on March 06, 2019, 04:54:13 PM
What about, though, if a previous civilization engaged in climate engineering (intentionally or otherwise)... could we possibly detect that? Like a previous global warming or cooling event not otherwise explained? How could we come to the conclusion it was caused by a civilization... or could we?
Well as I understand it, we have good records through ice cores about ancient temperatures, but such evidence only goes back a few hundred thousand years.
A slight quibble, given the time periods we are talking about. The oldest ice core is from 2.7 million years ago.
https://www.sciencemag.org/news/2017/08/record-shattering-27-million-year-old-ice-core-reveals-start-ice-ages
Quote from: Caliga on March 06, 2019, 04:52:09 PM
Quote from: Tamas on March 05, 2019, 08:21:51 AM
It is an entertaining what-if but unless we talk about a very small population secluded species reaching the earliest stages of Stone Age civilisation, I just can't believe we would not have found traces of them. Not possible.
I find it interesting to speculate about "what if the velociraptors reached sentience and had a stone age civilization" but I don't think anyone thinks that with our current level of technology we'd be able to uncover a primitive civilization like that. I think the concession is that we would need a past civilization to have deposited layers of radioactive material in order for there to be any chance at all of detecting them, right?
Not necessarily depositing layers, local remains of nuclear reactor fuel (likely identified by lower levels of U-235) from an era in which natural reactors weren't possible would be very strong evidence for an old civilization. The Oklo reactor of course is a nice demonstration of what could be learnt. Oklo was old enough to be natural, but was it
necessarily natural???!?
Quote from: Caliga on March 06, 2019, 04:52:09 PM
Quote from: Tamas on March 05, 2019, 08:21:51 AM
It is an entertaining what-if but unless we talk about a very small population secluded species reaching the earliest stages of Stone Age civilisation, I just can't believe we would not have found traces of them. Not possible.
I find it interesting to speculate about "what if the velociraptors reached sentience and had a stone age civilization" but I don't think anyone thinks that with our current level of technology we'd be able to uncover a primitive civilization like that. I think the concession is that we would need a past civilization to have deposited layers of radioactive material in order for there to be any chance at all of detecting them, right?
We would, if we found their tools. The "stone age" is so named because people at that level of civilization used stone tools ... and if fossils can survive, so can stone tools.
The issue would be whether any were found.
Quote from: Caliga on March 06, 2019, 04:52:09 PM
Quote from: Tamas on March 05, 2019, 08:21:51 AM
It is an entertaining what-if but unless we talk about a very small population secluded species reaching the earliest stages of Stone Age civilisation, I just can't believe we would not have found traces of them. Not possible.
I find it interesting to speculate about "what if the velociraptors reached sentience and had a stone age civilization" but I don't think anyone thinks that with our current level of technology we'd be able to uncover a primitive civilization like that. I think the concession is that we would need a past civilization to have deposited layers of radioactive material in order for there to be any chance at all of detecting them, right?
If we found fossils with a skull like this thing would have, then I'm pretty sure some scientists would go out on a limb and say it was intelligent.
(https://beforeitsnews.com/contributor/upload/106013/images/Collins-dinosauroid-Nov-2009.jpg)
Just how many hundred million year old fossils have we found? I'd imagine many species haven't been discovered or identified.
Quote from: crazy canuck on March 06, 2019, 05:18:12 PM
Quote from: Barrister on March 06, 2019, 05:10:10 PM
Quote from: Caliga on March 06, 2019, 04:54:13 PM
What about, though, if a previous civilization engaged in climate engineering (intentionally or otherwise)... could we possibly detect that? Like a previous global warming or cooling event not otherwise explained? How could we come to the conclusion it was caused by a civilization... or could we?
Well as I understand it, we have good records through ice cores about ancient temperatures, but such evidence only goes back a few hundred thousand years.
A slight quibble, given the time periods we are talking about. The oldest ice core is from 2.7 million years ago.
https://www.sciencemag.org/news/2017/08/record-shattering-27-million-year-old-ice-core-reveals-start-ice-ages
That's really cool!
Quote from: Eddie Teach on March 07, 2019, 12:36:47 AM
Just how many hundred million year old fossils have we found? I'd imagine many species haven't been discovered or identified.
100 million years is not that long ago, in fossil terms.
I can go into my back yard, turn over some rocks, and find
450 million year old fossils - Ordovician shale. The problem is not too few, it is too many - 99.9% of such fossils are boring, so you have to look through thousands of rocks filled with crinoid stems and shells to find a single trilobite; much invertebrate paleontology is done by amateurs, who do it for a hobby.
Lots of species have been found, but obviously a drop in the bucket compared with how many that existed - but then, we haven't identified the species that exist right now, let alone in fossil form.
https://www.amnh.org/our-research/paleontology/collections/fossil-invertebrate-collection/trilobite-website/gallery-of-trilobites/ordovician-period-trilobites
Here's some
500 million year old fossils with soft parts preserved, which is admittedly rare:
https://en.wikipedia.org/wiki/Burgess_Shale
Quote from: Barrister on March 06, 2019, 05:10:10 PM
Quote from: Caliga on March 06, 2019, 04:54:13 PM
What about, though, if a previous civilization engaged in climate engineering (intentionally or otherwise)... could we possibly detect that? Like a previous global warming or cooling event not otherwise explained? How could we come to the conclusion it was caused by a civilization... or could we?
Well as I understand it, we have good records through ice cores about ancient temperatures, but such evidence only goes back a few hundred thousand years.
Otherwise, we can infer what ancient climates were like through what kinds of vegetation is preserved in fossils.
Problem is if there was a rapid change in climate, that then lead to the extinction of the Silurian technological society, suich an event likely happened to quickly (geologically speaking) that not enough material would be deposited to ever be able to find.
You were one of those that was attacking me for theorizing about a civilization at the time of the oxygenation of the atmosphere, about 2.5 billion years ago.
Quote from: The Brain on March 06, 2019, 05:28:30 PM
Not necessarily depositing layers, local remains of nuclear reactor fuel (likely identified by lower levels of U-235) from an era in which natural reactors weren't possible would be very strong evidence for an old civilization. The Oklo reactor of course is a nice demonstration of what could be learnt. Oklo was old enough to be natural, but was it necessarily natural???!?
Hey I had totally forgotten about that 'natural nuclear reactor'. Is that the only one that has ever been found?
Quote from: Caliga on March 07, 2019, 09:06:37 PM
Quote from: The Brain on March 06, 2019, 05:28:30 PM
Not necessarily depositing layers, local remains of nuclear reactor fuel (likely identified by lower levels of U-235) from an era in which natural reactors weren't possible would be very strong evidence for an old civilization. The Oklo reactor of course is a nice demonstration of what could be learnt. Oklo was old enough to be natural, but was it necessarily natural???!?
Hey I had totally forgotten about that 'natural nuclear reactor'. Is that the only one that has ever been found?
I don't know of any other areas where they have been found.