131–140 of 181 posts
#Platypus
There have been many civilizations on Earth, maybe not many were industrial (ancient Egypt was clearly semi-industrial so far as lithic tooling is concerned.) We haven't looked deep enough very much. Many of the 10-25,000 year sites are buried dozens of feet underground. If there are any previous ruins, they're probably a hundred-or-more feet down. Seaside ruins from 10k+ years ago are now under 400 feet of water and…
as earth / plate tectonic move around, underneath earth is constantly surfaced... from dinosaur fragments, to Cambrian era mollusks found in top of mountains (due to earth's crust movement).
If there was a previous 'intelligent' civilization previous to us, they would have altered their environment to be detectable to us even today.
Yes, over geologic time, nearly anything has no chance of survival. And, yes, the lifetime of such a civilization may be a window that is, geologically, basically invisible. But an industrial civilization makes a LOT of stuff, and much of that is quite durable and easily recognizable as artificial, and is likely to be scattered all over the planet. Given that there are places that preserve tracks over 300 million yea…
The paper addresses this objection in section 1.3: “That this paper’s title question is worth posing is a function of the incompleteness of the geological record … The oldest extant large-scale surface is in the Negev Desert and is ~1.8 Ma old. However, pre-Quaternary land-evidence is far sparser, existing mainly in exposed sections, drilling and mining operations. In the ocean sediments, due to the recycling of ocea…
Most mountains in Europe have surfaced with the last 10-20 mill years, and they have turned earth around to the point that you routinetly find marine fossis in top of 2000m mountains.
If any civilization was around, it would have left a mark somewhere, and mountains would be a great place to spot them.
BTW: According to most scientists, the oldest mountain range on Earth is called the Barberton Greenstone Belt and is found in South Africa. It's estimated that the range is at least 3.2 billion (yes, billion!) years old.
Earlier quoted context omitted.
More broadly: survival. The crop that will grow or wither, the patient who will recover or die. Etc.
That's quite a different concept. Agriculture techniques would have evolved that way but entirely devoid of science or understanding of how they worked, just evolution of ideas ossified into wisdom. Colonists in new countries experienced crop failures because they couldn't predict how things would behave in the different climates/ecosystems and just applied their "dumb" knowledge. I heard about a hunter-gatherer soci…
So building war implements, like weapons and armor, and techniques, like how to target a canon, but also non-military disciplines, like the construction of buildings and bridges, the manufacture of commercial goods, etc.
Earlier quoted context omitted.
The paper addresses this objection in section 1.3: “That this paper’s title question is worth posing is a function of the incompleteness of the geological record … The oldest extant large-scale surface is in the Negev Desert and is ~1.8 Ma old. However, pre-Quaternary land-evidence is far sparser, existing mainly in exposed sections, drilling and mining operations. In the ocean sediments, due to the recycling of ocea…
that is disingenuous... and is just word playing with definitions. Most mountains in Europe have surfaced with the last 10-20 mill years, and they have turned earth around to the point that you routinetly find marine fossis in top of 2000m mountains. If any civilization was around, it would have left a mark somewhere, and mountains would be a great place to spot them. BTW: According to most scientists, the oldest mou…
[1] http://geomorphology.sese.asu.edu/Papers/Matmon%20et%20al.%2...
One of my favorite quotes from Iain M. banks’ Culture series, paraphrased here since I don’t recall which book it’s in, is that technological progress is more like scaling a rock face than climbing a ladder. There is so much room for surprise and incomprehension. I sometimes think about how vast the parameter space of our physical universe is, and if that vastness means we wouldn’t be able to recognize ancient advanc…
For your SD Card example though, I'll nitpick. Sure, just a card and explanation won't get you very far ... but I think something like an iPad (with a good power-supply) would produce enough evidence to convince them (depending upon the individual, I grant there might be some who just attributed it to supernatural forces even in the face evidence and explanation). I suspect humans in general are more willing to deal with "blackbox" technology that has practical application than most tinker types on HN would admit. Very little historical technology that was hard earned with trail-and-error has a theoretical basis known to even skilled practitioners. Even today, to most most people I know, the technology they use on a daily might as well be magic. Sure they know there some kind of "science" beyond it, but I'm also not sure they could convince me it wasn't just goblins if I demanded some theory of it worked.
The oldest hard-rock mountains are 1.5 billion to 3.5 billion years ago. Those include some heavily mined areas, such as the Appalachians, If a previous civilization had been into serious mining, we'd probably have seen evidence of that by now. There may be nothing left of the mine, but an area without the good stuff and the remains of a big rubble dump would be interesting. Conversely, a concentration of rusted meta…
That, and the real smoking gun: landfillite. Some significant fraction of landfills are going to fossilize into a pretty distinctive sedimentary rock. I don't know what it would look like, but it would have, like, fossil Barbie dolls in it. I don't think we'd have missed all of them if they existed. We could postulate an industrial civilization which just didn't make landfills? But we've only got ours to go on, and w…
Earlier quoted context omitted.
The thing is, it’s probably unbelievable when you do find evidence. https://archaeology-world.com/200-million-year-old-shoe-prin...
Interesting article, but unfortunately none of it is verifiable. It cites creationism.org (!!!) as a source and concludes that the fossil shoeprint is regrettably lost.
Another point that I don’t see made, is that if there was advanced tech, the “artifacts” were likely used until they ceased to exist and/or their purpose was lost.
Just think about our own society. If our entire power grid was lost, we would probably lose the ability to repair/rebuild them within a few generations. There may be pockets where electricity still runs, and some people will remember, but there will be no way to build new computers or phones, so they will invariably be brought to wherever electricity still exists, but even then, the ability to recreate them will cease to exist.
It more convincing to look at it the other way. It's not what such civilizations would have left, but what they would have taken. Our early civilizations found easily accessible deposits or tin, copper, gold, etc that would have been depleted if another advanced civilization had existed in the past 10 million years or so.
> The Anthropocene layer in ocean sediment will be abrupt and multi-variate, consisting of seemingly concurrent specific peaks in multiple geochemical proxies, biomarkers, elemental composition, and mineralogy. It will likely demarcate a clear transition of faunal taxa prior to the event compared to afterwards. Most of the individual markers will not be unique in the context of Earth history, but the combination of tracers may be. However, we speculate that some specific tracers that would be unique, specifically persistent synthetic molecules, plastics, and (potentially) very long-lived radioactive fallout in the event of nuclear catastrophe.
One that they didn't mention was our artifacts on the moon which will last 100 million years or so. Geostationary and HEO satellites will stay for a while but I'm not exactly sure how long.
However if you wait 50 million years or so, most of the stuff on earth won't be obvious and you would need to check very carefully.