Were there previous industrial civilizations before humanity's?

[Politesse]

But one unique quality of industrial civilizations is the ability to produce products that are not degradable by natural processes. Our plastics and so forth will linger for thousands of years. Our nuclear waste will persist for millions.

We really only have one industrial revolution to analyze. Do we know for certain that this is the fate of all industrial geneses? We certainly produce plenty of things that aren't eternal - most plastics are believed to degrade within a few centuries under normal conditions, actually, and lumber products barely make it a few years. Radioactive waste on the surface would be very difficult to recognize as such after a few million years, which seems to be the timescale the OP is positing.

 

[bilby]

But one unique quality of industrial civilizations is the ability to produce products that are not degradable by natural processes. Our plastics and so forth will linger for thousands of years. Our nuclear waste will persist for millions.

Some plastics (eg PVC) will last a long time, and are likely the best way to detect a past industrial civilisation in deep time. Mostly it will be microscopic granules after millions of years though, so hard to find unless you are specifically looking for it.

Nuclear waste is a less useful marker; It occurs naturally*, and would be very hard to destinguish from background after a few hundred years, without a careful isotopic analysis.

The phrase 'nuclear waste will be around for millions of years' is more propaganda than information - EVERYTHING non-radioactive will be around FOREVER, so nuclear waste is one of the less durable forms of waste material.





*And is therefore harmless under the Paltrow Principle

 

[skepticalbip]

When we find that abandoned research station on the Moon with about twenty million years of micrometeorite damage we will have a good idea that there was indeed an earlier advanced civilization. The question may then be if it was from earthlings or ETs though.

 

[bilby]

When we find that abandoned research station on the Moon with about twenty million years of micrometeorite damage we will have a good idea that there was indeed an earlier advanced civilization. The question may then be if it was from earthlings or ETs though.

The problem is, the Moon's a big place, and once it's got a good coating of moon dust, it's likely to be hard to spot. Particularly if (as would be sensible) much of it is under the surface. And even more so if it's close to one of the poles - which is a good spot if you are seeking ice for propellant, but not an easy spot to survey from orbit.

If it was left by ETs, you would expect it to be a black rectilinear hexagonal monolith with the proportions 1:4:9

 

[Jimmy Higgins]

If there was a civilization, there would have to be some sign of it via natural resource extraction. Gold, diamonds, dragon glass. I don't recall reading about how there was a gold mine that was already mined.

 

[bilby]

If there was a civilization, there would have to be some sign of it via natural resource extraction. Gold, diamonds, dragon glass. I don't recall reading about how there was a gold mine that was already mined.

Sure. If it was only a few tens or hundreds of thousands of years ago.

We are talking tens or hundreds of millions of years.

Enough time for almost the entire land surface of the Earth to be recycled. The minerals accessible a hundred million years ago are almost all inaccessible now - and even if you did stumble across one, how would you recognise the difference between a rock formation that is naturally low in minerals, and a hundred million year old mine site?

In a hundred million years, entire mountain ranges have been eroded to nothing, and new ones uplifted from nothing.

The very continents are different shapes, and in different locations. Perhaps there are the remains of a hundred year old copper mine somewhere in Antarctica. Would we ever be likely to know, if there was? Maybe there's another somewhere in Siberia, or the Sahara, or in the Amazon basin. We wouldn't be likely to find it; And if we did, we probably wouldn't recognise it for what it was without some very detailed analysis of the geology - analysis that nobody would bother with for low grade ore samples.

 

[phands]

This thread belongs in the Pseudoscience forum....it is utter bollocks.

 

[Jimmy Higgins]

If there was a civilization, there would have to be some sign of it via natural resource extraction. Gold, diamonds, dragon glass. I don't recall reading about how there was a gold mine that was already mined.

Sure. If it was only a few tens or hundreds of thousands of years ago.

We are talking tens or hundreds of millions of years.

Enough time for almost the entire land surface of the Earth to be recycled. The minerals accessible a hundred million years ago are almost all inaccessible now - and even if you did stumble across one, how would you recognise the difference between a rock formation that is naturally low in minerals, and a hundred million year old mine site?

In a hundred million years, entire mountain ranges have been eroded to nothing, and new ones uplifted from nothing.

The very continents are different shapes, and in different locations. Perhaps there are the remains of a hundred year old copper mine somewhere in Antarctica. Would we ever be likely to know, if there was? Maybe there's another somewhere in Siberia, or the Sahara, or in the Amazon basin. We wouldn't be likely to find it; And if we did, we probably wouldn't recognise it for what it was without some very detailed analysis of the geology - analysis that nobody would bother with for low grade ore samples.

Appalachians are about 500 million years old, I believe the oldest range on Earth. While these mountains have eroded a bit, are there any signs of coal mining, or any type of manipulation for transit? If you look anywhere on Earth, that'd be the spot.

 

[bilby]

If there was a civilization, there would have to be some sign of it via natural resource extraction. Gold, diamonds, dragon glass. I don't recall reading about how there was a gold mine that was already mined.

Sure. If it was only a few tens or hundreds of thousands of years ago.

We are talking tens or hundreds of millions of years.

Enough time for almost the entire land surface of the Earth to be recycled. The minerals accessible a hundred million years ago are almost all inaccessible now - and even if you did stumble across one, how would you recognise the difference between a rock formation that is naturally low in minerals, and a hundred million year old mine site?

In a hundred million years, entire mountain ranges have been eroded to nothing, and new ones uplifted from nothing.

The very continents are different shapes, and in different locations. Perhaps there are the remains of a hundred year old copper mine somewhere in Antarctica. Would we ever be likely to know, if there was? Maybe there's another somewhere in Siberia, or the Sahara, or in the Amazon basin. We wouldn't be likely to find it; And if we did, we probably wouldn't recognise it for what it was without some very detailed analysis of the geology - analysis that nobody would bother with for low grade ore samples.

Appalachians are about 500 million years old, I believe the oldest range on Earth. While these mountains have eroded a bit, are there any signs of coal mining, or any type of manipulation for transit? If you look anywhere on Earth, that'd be the spot.

'Eroded a bit' is masterful understatement. And why would we expect an ancient civilisation to mine a particular place? There are plenty of places on Earth today with high grade mineral ores, that are not being mined, because they are too remote from any infrastructure to make it worthwhile; And even more places that probably have even better ore that haven't even been prospected, for similar reasons.

The Appalachians are well situated for the current layout of our civilisation and the current positions of the continents. That doesn't imply that they were a suitable site for mining 100mya - and today's surface geology would have been deep underground back then. Even if there had been extensive mining, it could easily have all taken place above the current ground level, leaving no trace at all.

 

[Sarpedon]

ok, if we are talking 100 million years ago, we can count the presence of dinosaurs to disprove it. The rise of humanity led to a mass extinction of megafauna. Its hard to believe that a previous civilization wouldn't have done the same. Unless you are suggesting this civilization is responsible for the Cretacious extinction.

 

[bilby]

ok, if we are talking 100 million years ago, we can count the presence of dinosaurs to disprove it. The rise of humanity led to a mass extinction of megafauna. Its hard to believe that a previous civilization wouldn't have done the same. Unless you are suggesting this civilization is responsible for the Cretacious extinction.

Lots of things are hard to believe, but true; With only one datum, we cannot be sure that civilisations always lead to such extinctions. And there have been a number of megafaunal extinction events; The K-T event is pretty well understood (although even there, there is room for debate), but most such events are not.

The exact timescale is not important, and I use 100mya as shorthand because I have become bored with constantly typing "tens or even hundreds of millions of years ago"

 

[skepticalbip]

ok, if we are talking 100 million years ago, we can count the presence of dinosaurs to disprove it. The rise of humanity led to a mass extinction of megafauna. Its hard to believe that a previous civilization wouldn't have done the same. Unless you are suggesting this civilization is responsible for the Cretacious extinction.

How would the presence of dinosaurs disprove an advanced civilization during that epoch? Couldn't it be the case that the advanced civilization was a population of raptors that had evolved a high intelligence? If so then it could be the Cretaceous extinction that wiped out their civilization. There could not have been a human civilization 100 million years ago since there were no humans at that time.

 

[Bronzeage]

When we find that abandoned research station on the Moon with about twenty million years of micrometeorite damage we will have a good idea that there was indeed an earlier advanced civilization. The question may then be if it was from earthlings or ETs though.

The problem is, the Moon's a big place, and once it's got a good coating of moon dust, it's likely to be hard to spot. Particularly if (as would be sensible) much of it is under the surface. And even more so if it's close to one of the poles - which is a good spot if you are seeking ice for propellant, but not an easy spot to survey from orbit.

If it was left by ETs, you would expect it to be a black rectilinear hexagonal monolith with the proportions 1:4:9

That's strange. 1:4:9 is the exact proportions of that thing I found in my back yard when digging a pond. Don't know it was, but it made a really nice patio.

 

[bilby]

When we find that abandoned research station on the Moon with about twenty million years of micrometeorite damage we will have a good idea that there was indeed an earlier advanced civilization. The question may then be if it was from earthlings or ETs though.

The problem is, the Moon's a big place, and once it's got a good coating of moon dust, it's likely to be hard to spot. Particularly if (as would be sensible) much of it is under the surface. And even more so if it's close to one of the poles - which is a good spot if you are seeking ice for propellant, but not an easy spot to survey from orbit.

If it was left by ETs, you would expect it to be a black rectilinear hexagonal monolith with the proportions 1:4:9

That's strange. 1:4:9 is the exact proportions of that thing I found in my back yard when digging a pond. Don't know it was, but it made a really nice patio.

Did it also give you the inexplicable urge to brain your neighbour with a tire-iron?

 

[Loren Pechtel]

If there was such a civilization, they would have already mined or otherwise extracted the metals and other useful materials....we would have trouble finding sources....also where did it all go once extracted?

There cannot have been any receding industrial civilization.

Yup, this was my first thought. Only the first civilization on a planet gets the easily-mined resources.

This is also why recovery from a catastrophic collapse is not possible--the easily-mined resources are gone. No bronze age because they can't mine the stuff to make bronze. Likewise, no iron age. Even the late stone age is problematic. Once we fall below the level needed to support current extraction methods that's it. There might be a long decay period but there won't be a recovery.

 

[Loren Pechtel]

If there was such a civilization, they would have already mined or otherwise extracted the metals and other useful materials....we would have trouble finding sources....also where did it all go once extracted?

There cannot have been any receding industrial civilization.

That's simply not true. The timescales we are discussing are sufficient that almost the entire crust has been recycled; The areas they mined have long since been buried deeper than we can reach, and new crust brought to the surface.

While some areas have been redone there are plenty of old rocks around. Are we to think the civilization existed only in those areas that have been turned over? Why didn't civilization expand?

Also bear in mind that every single atom of metal not sent out of the Earth's gravity well as space probes is still here. We don't use up resources; We just move them around.

It's a matter of entropy--we take concentrated sources and spread them about so thinly that mining isn't practical (except landfill sites.)

If humans disappeared today, fifty million years from now any place that used to be a city, and that is still close enough to the surface to mine, would bear a striking resemblance to a rich ore body.

Perhaps for iron. Not for most things.

 

[bilby]

If there was such a civilization, they would have already mined or otherwise extracted the metals and other useful materials....we would have trouble finding sources....also where did it all go once extracted?

There cannot have been any receding industrial civilization.

Yup, this was my first thought. Only the first civilization on a planet gets the easily-mined resources.

This is also why recovery from a catastrophic collapse is not possible--the easily-mined resources are gone. No bronze age because they can't mine the stuff to make bronze. Likewise, no iron age. Even the late stone age is problematic. Once we fall below the level needed to support current extraction methods that's it. There might be a long decay period but there won't be a recovery.

That would be true if (and only if) extraction destroyed those resources (in contravention of the first law of thermodynamics, or by launching them into deep space); and if (and only if) what resources were easy or difficult to reach didn't change radically in the timescales we are considering.

Neither is true.

Even widely dispersed materials will be re-concentrated by geological processes at such timescales.

 

[Loren Pechtel]

It's amazing that we know as much as we do about the dinosaurs, and they were around in huge numbers for over a hundred million years. A civilisation that was only around for a few centuries, tens of millions of years ago, might well have vanished without a trace; Or the only evidence of it might be somewhere we haven't yet looked in any great detail. There's LOTS of geological structures about which our knowledge is scant at best; If there are some artifacts buried a few feet below the surface in the high Himalayas, or the deep Sahara, then we may never find them.

In a hundred million years, the surface of the Moon might be the best place to look for easily found signs that we were here (for a given value of 'easily').

In a hundred million years there would still be an awful lot of mined-out ore bodies. It would be very strange indeed that mining would be so much harder in any rock older than 100 million years. You don't need to find a single artifact to see this.

(Not to mention that it would be basically impossible for a civilization to arise 100 million years from now anyway--global warming will not be friendly to large slow-reproducing (and thus slow-evolving) species by then.)

 

[Loren Pechtel]

But one unique quality of industrial civilizations is the ability to produce products that are not degradable by natural processes. Our plastics and so forth will linger for thousands of years. Our nuclear waste will persist for millions.

Some plastics (eg PVC) will last a long time, and are likely the best way to detect a past industrial civilisation in deep time. Mostly it will be microscopic granules after millions of years though, so hard to find unless you are specifically looking for it.

Nuclear waste is a less useful marker; It occurs naturally*, and would be very hard to destinguish from background after a few hundred years, without a careful isotopic analysis.

The phrase 'nuclear waste will be around for millions of years' is more propaganda than information - EVERYTHING non-radioactive will be around FOREVER, so nuclear waste is one of the less durable forms of waste material.





*And is therefore harmless under the Paltrow Principle

Disagree--while it won't be dangerous at a million years we would still find several isotopes that have no natural origin. That would show fission was going on and since they could figure the U-235/U-238 ratio at the time they could figure out it wasn't a natural reactor.

Furthermore, there's another product of modern civilization that can be detected by nuclear means even after it's form is long gone: depleted uranium. What are all these little areas of uranium that seriously does not match the overall planetary ratio?

- - - Updated - - -

Appalachians are about 500 million years old, I believe the oldest range on Earth. While these mountains have eroded a bit, are there any signs of coal mining, or any type of manipulation for transit? If you look anywhere on Earth, that'd be the spot.

You're barking up a telephone pole! (So wrong it's not even the wrong tree.) Mountains erode, that's not where you look.

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

 

[Angra Mainyu]

It's an interesting question. I think it's very improbable, though. In addition to some points already made in the thread, I would mention two pieces of evidence (in increasing order of strength):

1. Fossils:

bilby correctly points out that they're rare, but we keep finding the fossils of early hominids and australophitecines up to 3+ million years ago. Sure, that's much less than 50 or 100 million years, but then, the numbers of individuals of those species were far lower than the absurdly high numbers of humans on the planet - and on pretty much every corner of the surface of the planet, save for Antarctica, so that includes areas with favorable conditions for fossilization. We have not found any old skull compatible with anything smart enough to have an advanced civilization. This may not be decisive, but it does seem to provide considerable evidence, at least for much of the past.

What about a much smaller civilization?
Also bilby mentions one possibility. But what is the prior of that small civilization? That leads to the second (and I think stronger) point.

2. Our industrial civilization has only lasted for a very short period. In fact, it's been less than 300 years from the Industrial Revolution. If our civilization goes on for, say, 300 more years, its blueprints will almost certainly be far from Earth, in the form of:

a. Moon bases (also mentioned by bilby, but I'm talking about much larger facilities).
b. Martian bases.
c. Probably very large space stations - large enough to be recognizable even after tens of millions of years of micrometeors.

If our civilization goes on for 1000 more years (and I'm being conservative here), there will be sustainable colonies on Mars and probably other places, and after that, it's hard to see what might destroy it. Maybe massive interplanetary warfare, alien attack or crazy AI, but any of that is likely to leave either good evidence or the aliens/crazy AI themselves!

My point is that in geological or even evolutionary timescales, there is an extremely short window for an industrial civilization to exist without leaving a lot more evidence than ours - but ours has already left quite a bit, some mentioned by Loren Pechtel, plus the potential fossils (point 1).

So, one may ask: if there was a previous industrial civilization, what happened to them, and wouldn't that leave evidence?

Asteroids, comets, or things like that, are extremely improbable to wipe them out. The reason: those events are extremely rare, so what are the odds that an industrial civilization gets wiped out by one of them before it colonizes the Moon and Mars (and gets the tech to divert them, by the way) is very low. Something similar goes for things like gamma-ray bursts. Crazy AI is extremely improbable, because where is the AI? (okay, crazy suicidal AI, or something, but it does seem pretty improbable).

Perhaps the most likely scenario is war. But what sort of war would really kill us off? It's hard to say. Even global nuclear war does not guarantee extinction, and if there are humans left and widely distributed, chances are they will build eventually an industrial civilization. Maybe a nuclear war with even more advanced nukes? But then we're close to the "interplanetary war" scenario. Even a massive enough nuclear war seems to leave traces for a very long time.

Of course, global warming or things like that aren't going to do it.

In short, these sorts of civilizations seem to be very hard to kill without means massive enough to leave plenty of long-lasting evidence.

Now, granted, nonhumans may have different minds and interests, but if they already developed an industrial civilization, it seems likely they'll want to just stop at Earth.