Technical ceramics would have survived.
The Silurian Hypothesis (2020)
41–50 of 130 posts
Re: The Silurian Hypothesis (2020)
#42So we have microbial fossils from 3.5 billion years ago, fossilised 300 million year old skin , bones from almost 200 my ago, even actually soft tissue inside a fossilised bone from 70 my ago. Ah, footprints too, the most unsubstantial matter of all: pure shape. That's in addition to all the million other fossils that are so common we hardly care: shells, small bones, etc. And someone is saying there could have been…
> And someone is saying there could have been an entire advanced civilization 400 million years ago, large and powerful enough to cause climate change, and that no traces of it would possibly be left? If humanity vanished today, in 1 million years almost all of our artifacts would be gone or burned under miles of subduction. In 10 million years there would literally be nothing left.
> If humanity vanished today, in 1 million years almost all of our artifacts would be gone or burned under miles of subduction.
That is completely incorrect. We have sedimentary rocks from 100 M years ago on the Earth’s surface right now, that never underwent any kind of subduction.
Re: The Silurian Hypothesis (2020)
#43So we have microbial fossils from 3.5 billion years ago, fossilised 300 million year old skin , bones from almost 200 my ago, even actually soft tissue inside a fossilised bone from 70 my ago. Ah, footprints too, the most unsubstantial matter of all: pure shape. That's in addition to all the million other fossils that are so common we hardly care: shells, small bones, etc. And someone is saying there could have been…
> And someone is saying there could have been an entire advanced civilization 400 million years ago, large and powerful enough to cause climate change, and that no traces of it would possibly be left? If humanity vanished today, in 1 million years almost all of our artifacts would be gone or burned under miles of subduction. In 10 million years there would literally be nothing left.
> under miles of subduction
Subduction only occurs at plate boundaries and is not nearly this fast. Continental plates float on top like foam and do not get subducted. It's the oceanic plate that is created at mid-ocean ridges and gets subducted at the margins.
Re: The Silurian Hypothesis (2020)
#44Earlier quoted context omitted.
The counter argument: dinosaurs were around for a staggering amount of time, no pun intended. 165 million years is reasonably long enough to ensure they left behind some nests, bones, and a feather or two. Modern humans have been around for more like 0.02 million years. The counter-counter argument is that while we’ve been here for a comparative blink of an eye, we’ve left behind 4 orders of magnitude more stuff than…
Yea, but if humans went extinct tomorrow, very little human artifacts would remain after millions of years. Indeed, most would be gone well before that. How much stuff from the 18th century still remains, in percentage terms?
There would still be many signs. Dug up mines, metal alloys that don't exist in nature along with refined metals in quantities they don't exist, animal and plant species we bred along with all the ones we made extinct.
Re: The Silurian Hypothesis (2020)
#45Earlier quoted context omitted.
The counter argument: dinosaurs were around for a staggering amount of time, no pun intended. 165 million years is reasonably long enough to ensure they left behind some nests, bones, and a feather or two. Modern humans have been around for more like 0.02 million years. The counter-counter argument is that while we’ve been here for a comparative blink of an eye, we’ve left behind 4 orders of magnitude more stuff than…
Indeed. Did a rapid check on T-rex, just as an example. Was around for max 3.6 million years. Max population at any one time must have been around 20k individuals. We have about 150 skeletons. So current human population is 400 thousand times the maximum T-rex population at any one time. A few decades are enough to produce more human individuals than the entire T-rexes history. We also have the ability to go (and die…
>We also produce an absolutely staggering amount of artifacts of all kinds, from plastic straws to giant tunnels and artificial caves.
Plastic will be gone in ~1000 years,
https://www.activesustainability.com/environment/waste-plane...
tunnels and artificial caves in a few million years at most as they are compressed by the weight of the rocks above them ("tunnel squeezing").
Re: The Silurian Hypothesis (2020)
#46I don't think we have to go that far back. Plate tectonics, submersion and weathering does a good enough job of wiping the slate clean off the surface of the Earth, that any evidence of earlier hominids developing pre-industrial, coastal civilizations say, a million years ago, would be now under the crust. What we consider civilization is about 5000 years old, so it's not inconceivable that the cycle might have occur…
Huh?
We have plenty of fossil evidence from, from your example, a million year old hominids. Far more than we would need to expect to see evidence of civilization.
Subduction makes up for a tiny tiny proportion of where coastal land "goes" in any age.
You'd need an enormous set of coincidences for a past civilization of hominids to go unnoticed.
Re: The Silurian Hypothesis (2020)
#47Petroleum could be the byproduct of a previous civilization. Also, just as we "engineered" animals and plants through selective breeding, previous animals/plants could have been the results of selective breeding by a previous civilization: There'd be no way to tell just as there'd be no way to tell our "tampering" a few million years in the future.
> Petroleum could be the byproduct of a previous civilization. How so? We know how it forms, there is no real gap in understanding there. What could lead to the kind of distribution of oil and gas fields we can observe?
Just fun to think about and base fiction on
I mean, would an ant walking on a highway be able to tell that it's artificial?
Re: The Silurian Hypothesis (2020)
#48So we have microbial fossils from 3.5 billion years ago, fossilised 300 million year old skin , bones from almost 200 my ago, even actually soft tissue inside a fossilised bone from 70 my ago. Ah, footprints too, the most unsubstantial matter of all: pure shape. That's in addition to all the million other fossils that are so common we hardly care: shells, small bones, etc. And someone is saying there could have been…
> And someone is saying there could have been an entire advanced civilization 400 million years ago, large and powerful enough to cause climate change, and that no traces of it would possibly be left? If humanity vanished today, in 1 million years almost all of our artifacts would be gone or burned under miles of subduction. In 10 million years there would literally be nothing left.
Bollocks. We find fossils millions of years old right on the surface.
Re: The Silurian Hypothesis (2020)
#49Isaac Asimov's Nightfall [0], but on a longer cycle? Jokes aside, what is the evidence, beyond "Ancient mystical texts"? [0] http://www.myths.com/pub/fiction/science-fiction/Asimov/Nigh...
I think there is no evidence for it, but I think the point of the Silurain hypothesis (which the article does not convey well) is that if there were such civilisations we would not know as its unlikely we would find any evidence.
So it not a falsifiable statement from the onset?
Re: The Silurian Hypothesis (2020)
#50So we have microbial fossils from 3.5 billion years ago, fossilised 300 million year old skin , bones from almost 200 my ago, even actually soft tissue inside a fossilised bone from 70 my ago. Ah, footprints too, the most unsubstantial matter of all: pure shape. That's in addition to all the million other fossils that are so common we hardly care: shells, small bones, etc. And someone is saying there could have been…
Actually correct. We have very very few fossils compared to the millions of species that have evolved and gone extinct over 4 billion years. The fossils we do have are of highly successful species in that geography. It’s a matter of chance, leaving behind a fossil, after all. And unlike biological matter that can fossilize, industrial structures etc do not. All our manufactured stuff has very short life once it reach…
> It’s more showing you the limits of scientific inquiry into the deep history of Earth.
I think this is it: the point of this argument is to inspire some awe in the listener, making them realise how vast Earth's time is compared to our horizons.
But in practice, the argument is wrong. A dead animal's skin is expected to lasts weeks to months- and yet we have fossilised specimens. A footprint typically lasts hours, and yet we have ones that are hundreds of millions of years old. Even if the expected lifespan of our artifacts is nothing in comparison with these timespans, a small percentage of artifacts will either be preserved or leave recognisable traces- exactly as it happened for soft tissues and footprints. It's extremely naive to think that none of this will leave traces.