Comment by markus_zhang
7 hours ago
However, since we do have plenty of fossils from Silurian, it is hard to believe that none of the advanced technologies never left any hint. Any idea?
7 hours ago
However, since we do have plenty of fossils from Silurian, it is hard to believe that none of the advanced technologies never left any hint. Any idea?
Yes. We'd find mines, where the richest veins were mined out and what's left is spread in a pattern that clearly appears to be "a rich deposit but with the best stuff taken already". The mine itself would have long collapsed but would also leave interesting evidence, a pattern of mismatched geological layers that rather than looking like an earthquake or a tectonic upheaval would be something that is relatively clearly shaft-shaped and if followed into the mountain would open out into a pattern that indicates intelligent mining activity as the anomaly is further charted.
Places where there is suddenly a vast collection of foreign rocks from the other side of the world that can't be explained by glaciers.
Radioactivity from nuclear tests that can't be explained by stellar phenomena and leave a layer of weird isotopes and isotope ratios all around the world, as we already have done.
And while we aren't to the point we'd have found this quite yet necessarily, evidence on the Moon where unlike Earth evidence probably would in fact persist for millions of years, especially if it ever attained any scale, e.g., "a large complex of cities" might still leave a visible mark on the surface easily visible to modern satellites and clearly with no other explanation available as to what caused it.
People get stuck on the idea that the only way to determine there was intelligent life earlier is to find a super complicated artifact which obviously can't survive, but there are footprints we've left in the world that are way, way larger than a cell phone or even a major city.
I don't find it hard to believe we've lost entire human civilizations. In fact I'd call it the smart bet. Maybe those civilizations were even a bit more sophisticated than we'd have thought, with maybe an earlier and entirely unknown Iron Age popping up somewhere for some period of time or something. But this is the first major technological civilization this planet has ever seen, even across geological time scales. And those lost human civilizations never reached to the level where they took all the easy resources like we have, because if they had, we wouldn't be able to get them. Some resources we call "non-renewable" do replenish on a few million year time scale, but we also pull lots of resources out of billion-year-old rocks, such as copper mines in northern Michigan which are pulling resources out of pre-Cambrian rocks. Clearly nobody else has been there, at scale.
The exception that proves the rule is a nuclear reactor from Gabon that dates to 1.7bn years ago... and which was clearly natural, a uranium-rich cave got flooded and went supercritical: https://en.wikipedia.org/wiki/Oklo
Of course we haven't discovered everything. But it seems very likely that if there were a civilization's worth of slag from 500m years ago, we would have discovered it.
A more interesting question is the civilizational technology of domestication, especially since that is short-term technology coupled with long-term evolution. It does seem possible (but purely fantastical) that Earth had talking dinosaurs with sophisticated ideologies and mythologies, feeding dumber dinosaurs and curating the growth of nutritious plants, the descendants of which all died 65m years ago.
People get way too excited about the word "reactor". They hear "reactor" and think "oh, a natural formation of uranium was evaporating water into steam and generating electricity". They don't consciously examine that, of course, but it's clear a lot of people are letting that in unexamined.
What really happened is that some uranium got concentrated, and then it did was uranium does.
Similarly, if you want to make a very, very basic atomic bomb, you can do it by picking up two subcritical bits of uranium of the right isotopes and slamming it together in your hands. Basically the demon core but even more pure. The yield will be pathetic by military standards but you won't be around to care.
Fission isn't a process that requires intelligence, and fission causing cascading fission doesn't either.
"A more interesting question is the civilizational technology of domestication, especially since that is short-term technology coupled with long-term evolution. It does seem possible (but purely fantastical) that Earth had talking dinosaurs with sophisticated ideologies and mythologies, feeding dumber dinosaurs and curating the growth of nutritious plants, the descendants of which all died 65m years ago."
Yes, that's why I'm careful to qualify it with "technological", which is by implication the whole thing we do with metals and minerals and oil and all that stuff. A past intelligent society that lived like hippies and had all sorts of fascinating philosophical debates until they died out with no major footprint can't be completely excluded. But I am fairly confident they never went to space. Well... you know... real space, like the kind of orbit the ISS is in. What they may have gotten up to on the influence of drugs I have no comment about.
Part of the reason I couldn't exclude it is that it has basically happened. If hypothetically an asteroid blew away humanity two or three thousand years ago, that's basically what would have been left behind. They did mining then, but at a scale easy to believe could be erased by time. Quite a bit of that time period is already gone as it is, let alone across millions of years. It's really that modern industrial mining that we do today, the cumulative effect of many decades of that mining, and barring disaster, the cumulative effect of yet more decades/centuries of mining that would survive for millions of years.
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> People get stuck on the idea that the only way to determine there was intelligent life earlier is to find a super complicated artifact which obviously can't survive
Why is it obvious that none of them can survive? Ordinary bones can become rocks (fossils) that are preserved. If mining of iron ore is visible, things would have been made out of iron -- wouldn't a large structure made out of iron leave some trace? Or even a small one? Why are there dinosaur fossils galore, but not so much as a pre-human fidget spinner to be found?
I'm not to stuck on the complete, 100% impossibility of things to be found.
But one counterargument that can be made is that fossilization requires very specific circumstances, and the legacy of the dinosaurs is from millions of years of opportunities. A blip of a 500 year civilization might not leave much behind.
No, I wouldn't expect a big pile of iron to leave anything interesting behind. It would rust, and rust has no structurally integrity and probably wouldn't resist the general forces of time very well. On geological timeframes rust is soluable in water.
However, I couldn't tell you that about every last industrial artifact we have. Could the Hoover Dam still indicate some sort of obvious construction activity a few million years hence? Could some of the concrete end up preserved and some future civilization realize that it is too precisely formulated for an engineering purpose to be constructed? Could some titanium structure survive for extended periods of time even though everything else in the plane or whatever else is long gone? Could New Orleans end up sinking into muck and leave some sort of fossilization behind of things that are still clearly artifacts millions of years later? It's hard to prove that every last thing we create has absolutely no chance of being recognizable as an artifact even in millions of years.
Especially if we leave Earth and start including the moon. Just a few things here or there could be wiped out with an unlucky asteroid strike, but if something was really systematically up there for long periods of time doing intelligent things, even hundreds of millions of years ago, could still leave an obviously-intelligent footprint.
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> Any idea?
Not really, because none of this passes the smell test if you know even a tiny bit about geology and paleontology. The most solid arguments are religious texts, there is not really any substance other than that.