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Was There a Civilization On Earth Before Humans? (theatlantic.com)
Adam Frank, writing for The Atlantic: We're used to imagining extinct civilizations in terms of the sunken statues and subterranean ruins. These kinds of artifacts of previous societies are fine if you're only interested in timescales of a few thousands of years. But once you roll the clock back to tens of millions or hundreds of millions of years, things get more complicated.
When it comes to direct evidence of an industrial civilization -- things like cities, factories, and roads -- the geologic record doesn't go back past what's called the Quaternary period 2.6 million years ago. For example, the oldest large-scale stretch of ancient surface lies in the Negev Desert. It's "just" 1.8 million years old -- older surfaces are mostly visible in cross section via something like a cliff face or rock cuts. Go back much farther than the Quaternary and everything has been turned over and crushed to dust.
And, if we're going back this far, we're not talking about human civilizations anymore. Homo sapiens didn't make their appearance on the planet until just 300,000 years or so ago. [...] Given that all direct evidence would be long gone after many millions of years, what kinds of evidence might then still exist? The best way to answer this question is to figure out what evidence we'd leave behind if human civilization collapsed at its current stage of development. Mr. Frank, along with Gavin Schmidt, Director of the NASA Goddard Institute for Space Studies, have published their research on the subject [PDF].
When it comes to direct evidence of an industrial civilization -- things like cities, factories, and roads -- the geologic record doesn't go back past what's called the Quaternary period 2.6 million years ago. For example, the oldest large-scale stretch of ancient surface lies in the Negev Desert. It's "just" 1.8 million years old -- older surfaces are mostly visible in cross section via something like a cliff face or rock cuts. Go back much farther than the Quaternary and everything has been turned over and crushed to dust.
And, if we're going back this far, we're not talking about human civilizations anymore. Homo sapiens didn't make their appearance on the planet until just 300,000 years or so ago. [...] Given that all direct evidence would be long gone after many millions of years, what kinds of evidence might then still exist? The best way to answer this question is to figure out what evidence we'd leave behind if human civilization collapsed at its current stage of development. Mr. Frank, along with Gavin Schmidt, Director of the NASA Goddard Institute for Space Studies, have published their research on the subject [PDF].
There are those who believe that life here began out there, far across the universe, with tribes of humans who may have been the forefathers of the Egyptians, or the Toltecs, or the Mayans, that they may have been the architects of the Great Pyramids, or the lost civilizations of Lemuria or Atlantis. Some believe that there may yet be brothers of man who even now fight to surviveâ"somewhere beyond the heavens!
The place to look for civilizations that pre-date us is, of course, Antarctica. We really have not done much exploring of the Transantarctic Mountains. Who knows what might be found there.
Another day closer to redwood heaven
But where is the space-junk?
You are assuming they existed long enough to reach a space age. They may have just reached the age of steam then collapsed. The fact they they failed to do something about the incoming asteroid would support this clam.
There is another answer too. If they did reach the space age they might have simply been more tidy about space than we are. Plus a 70+ million years is plenty of time for all orbital space junk to fall back to earth.
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Well if we can still find fossils of dinosaurs many millions of years old that were not "crushed to dust" wouldn't a city leave some trace?
I find both the Drake equation and this hypothesis to be faulty.
The Drake equation outputs whatever you decide to plug into it. It is a fine mathematical example of manipulating non-scientific people since the input to the equation is the supposition. Any faulty supposition gives an erroneous output. We do not know what the input should be. Therefor we do not have an accurate output.
The supposition that an entire city would leave *nothing* when the bones of ancient animals can be found is a faulty presupposition.
Another consultant who stuck it out.
"We are the Priests, of the Temples of Syrinx..."
Glass doesn't rust but over time environmental forces will turn glass back into its sandy components.
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Layers and layers of compressed shoes.
No sig today...
But where is the space-junk?
You are assuming they existed long enough to reach a space age. They may have just reached the age of steam then collapsed. The fact they they failed to do something about the incoming asteroid would support this clam.
There is another answer too. If they did reach the space age they might have simply been more tidy about space than we are. Plus a 70+ million years is plenty of time for all orbital space junk to fall back to earth.
Maybe they made it off this rock and we are the descendants of some pets that got left behind to run wild.
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
the current area of urbanization is less than 1% of the Earthâ(TM)s surface (Schneider et al., 2009), and exposed sections and drilling sites for pre-Quaternary surfaces are orders of magnitude less as fractions of the original surface
And yet we keep finding buried and hidden signs of civilisations in the middle of the Amazon, and fossilized remnants of long extinct species in the middle of Africa.
They're also ignoring that any reasonable civilisation would have been likely to build their urban centres in many of the same locations we have; near water. This isn't a cultural preference; it's a huge logistical advantage. Given that we've been doing a hell of a lot more excavating near coastlines than we have in the middle of the Canadian tundra, the odds of finding signs of a past culture are WAY higher than the stated 1%.
The paper addresses this geological impact paradox. For the signal to be obvious in the geological record, it has to be sustained, but for a civilization to persist long enough to be obvious in geological time scales, they have to be in equilibrium with the environment.
We already had a steam age around 100 BC.
https://en.wikipedia.org/wiki/...
But people that time had no idea what to do with them, they used them for "spectacular tricks" like "magically" opening huge doors of temples.
If we once had another civilization (there are plenty of plausible reasons, which I will explain in another post) then two thinks are most important to consider:
a) coverage of the ground with dust. The city Troy has about 9 layers of destroyed buildings and rebuild buildings on top of it. And that is a town just 5000 years old. When it was found it was more or less unrecognizable covered under earth.
b) Considering the last "ice age", sea levels where some 120m lower than now. E.g. Australia was nearly connected with Asia via a land bridge. A civilized nation most likely would have many cities at the coast. Today that would be hundreds if not thousands of miles away from the coast line. In water depths of about 120+ meters. And obviously, depending of about what time frame we are talking, last "ice age", or 6 "ice ages" ago, those areas would be covered with perhaps a mile of mud.
No one is searching dozens or hundreds or thousands of kilometers out in the sea in depths around 150m - 60m under a mile or hundred meters of sludge. If you would try to get funding for something like this people would declare you mad. Anyway, if another Schliemann shows up and gets enough funding I could imagine we find something (note: I said imagine, not that I'm convinced or believe there is something)
Here, two nice pictures about coast lines and sea levels: https://www.iceagenow.com/Sea_... Note Japan, Indonesia, North America and Europe, the land bridge closing Spain with north Africa. The second picture has the outline of the coast lines during the last "ice age" as a grey frame around the green land masses.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Glass rarely survives intact after even a century of neglect. After millions of years of earthquakes, hailstorms, wild-fires, hurricanes,etc,etc,etc - how would you recognize leaded sand in amongst all the other grains? Metals rust, plastics degrade. Hard stone is about the only thing we could reasonably expect to survive intact.
Mining tunnels would probably be one of the few things we could reasonably expect to find evidence of - and you'd have to be looking really hard to recognize the telltale geologic anomalies distinguishing a tunnel that collapsed millions of years ago.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
We were the first to mine coal, drill for oil, extract deposits of rare earths, and precious metals.
Citation needed.
Also, some things shouldn't go missing. Tracks on the moon
Why would they have necessarily gone to the moon, and even more importantly, why would one of our very few manned missions, or other landing craft, have landed in the right place to have seen those tracks? If we're talking about the scale of millions of years, wouldn't an impact on the moon be an obvious candidate for removing evidence?
orbital satellites
Satellites in a stable orbit for millions of years? The moon is not in a stable orbit when you're talking about geologic time.
undecomposable manmade polymers and alloys
I don't think we've made anything that would be considered "undecomposable" after millions of years. Moreover, even if we could, wouldn't they be buried after millions of years instead of sitting on the surface?
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
Why would an ancient civilization use nuclear power?
Because it's a clean, reliable, and safe means of generating electricity for a technologically advanced society to use. Assuming they don't have a bunch of smelly fucking hippies get in the way of developing into such clean, reliable, and safe source of power.
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There would be no secrecy. You maybe able to keep government source like NASA silent. You would still have to deal with all the university astronomy projects. But lets say you managed to keep the university programs secret, then you need to deal with the hundreds of thousands of amateur astronomers.
An these are only U.S. based projects. There are still 200 countries in the world, most with their own astronomy programs. You are not going to keep a extinction level asteroid secret for long.
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Abuse, yes. Neglect, no. We have glass artifacts in perfect condition from the Mesopotamians (1500BC/3500yr). Glass is just a form of stone you know. And, if by "rarely survives intact" you mean down to unrecognizable as manufactured, then you're much, much more incorrect.