I don’t know if this is the type of question that is cut and dry of there is some flexible room for debate, so feel free to move (or not).
Let’s presume that the Cold War had gone hot and all of humanity died in a nuclear holocaust or its immediate aftermath. Now let’s assume that, 100+ million years later a future intelligence comes to earth (aliens, a new civilization arises from some species, whatever). Now, would these beings be able to look at the fossil/archaeological data and go “HOLY SMOKES!” with the realization that there was someone way back in time?
I assume that they could tell there was a massive extinction (I assume the planet being bathed in nukes would do that, anyway). Would they be able to tell anything beyond that? I mean, I assume the radiation would be gone, and I would guess our cities would simply be flattened and totally unrecognizable from any other kind of deposit, unless the alloys would stand out.
THere would still (probably) be artifacts on the moon, and perhaps on Mars…I suppose there MIGHT still be some of our space junk still about too. 100 million years though…thats a pretty long time. I’m unsure how much of our civilization would still be around to be dug up in that time. Even the scars of a nuclear war wouldn’t last that kind of time, though there would probably be sedimentary evidence if any alien civilization REALLY wanted to look closely.
At a guess, if they REALLY dug around, they’d find some evidence that there was a technological civilization once on the earth though.
I doubt it…not in 100 million years. No radiation (that I know of) has such a long halflife. I also doubt many buildings would still be around in that kind of time frame RM…thats a LONG time. My thoughts were that some things that would be buried could be excavated and show there was a civilization here before.
Not sure about the satelites either…again, thats a LONG time for them to remain. Still, I conceed that some things might remain…and certainly the stuff we left on the moon and in the solar system MIGHT make it.
I just thought it was interesting because I’ve heard musings that, you know, we could be that second race and something like that might have happened a LONG time ago and we might never even know about it except maybe it caused a mass extinction.
Well…but we have the fosil record and all that. I’d think we’d know if there was an advanced civilization that was millions of years old…SOME artifact would show up eventually so far out of wack with everything else that it would be appearent.
The key would be how much study would these ‘aliens’ want to spend excavating the Earth? If they spent as much time as WE do digging about I’m sure they would eventually find something…bit of old building, some artifact sheltered in neutral soil or some other environmental protecting agent…something in the ocean perhaps in one of those north seas areas with very low oxygen content yet high water movement so that nothing would grow on it and it wouldn’t be buried…something. The problem is your time frame…100 million years is a LONG time for artifacts to remain. I’m not even sure glass would last that long (I could be wrong here…I don’t remember how long it takes for glass to completely deform its shape…just that its a VERY slow moving liquid :)).
I’d guess that in 100,000,000 years time, pretty much all buildings up to and including the pyramids would be nothing but dust.
That dust, however, would still be identifiable as something. We can see the results of bid meteortite strike from the K/T boundary. Something like that would remain if we all went up in radioactive smoke.
There could be:
[ul]
[li]radioactive glass[/li][li]oddball organic compounds (PCBs, dioxins etc)[/li][li]a metal rich layer (all our cars etc could rust)[/li][li]sedimentary layers of interstate highways[/li][li]Cheyenne Mountain would still be hollow[/li][/ul]
If you looked hard enough, you’d have to conclude something weird had gone on.
Well from what my proffessor told me a few years back, (paraphrasing) most of archeaolgical study of early man is a done by picking through his garbage. (/paraphrasing) Old fire pits and the charred remains of food, discarded tools tell us about diet, and level of sophistication of our ancestors.
Our civilization has left quite a large landfill to pick through, including actual landfills.
It has been found that many of our perishable discarded goods have actually mummified instead of decomposing in those rubbish piles.
Even if the whole mess completely breaks down over the time we are talking about, the chemical soup left behind will perk some interest as it will be a mix of items that will not be found naturally occuring.
In early neolithic sites we can tell where tents were made by the disrupted earth where post holes were made. Imagine the post holes we leave with our buildings. We have disrupted a great deal of land through excavation. Much of that will get covered through growth of vegetation its dying and decomposing over the years. Chances are when you look at the layers you will see the signs of that excavation.
Other signs include the movement of resources from one part of the earth to another, which could also be charted.
For example if we have Soap stone sculpture remains in an area far from the natural source, that could be an indication that a somewhat sophisticated civilization may have existed… or perhaps aliens moved them.
If nothing else, I would suspect that all the materials of diverse origins accumulated in our cities would result in very weird deposits in the places where they were situated, that couldn’t be explained by any natural event.
I was thinking along those lines too (especially soil/rock with a high aluminum and iron content for no discernable reason).
And Tapioca, you brought another thing to mind… in another 100,000,000 years, the aliens might find mineral deposits weirdly located, but our fossil fuels would have regenerated!
Yeah, they’ll know we were here. There’ll be great big piles of billions and billions of AOL sign-up disks, among them the three I got in the last two weeks and the dozens of others I’ve thrown away. Also, in about a hundred million years or so (given the speed of light limitation) they’ll be receiving e-mails offering to make them rich with shady deals involving Nigerian and South African banks, Viagra and porn at super-cheap prices, and they’ll be delighted to learn that several times a week they’re winning millions and millions of dollars in lotteries they never even knew they’d entered. And that’s not even mentioning the insipid sit-coms and retarded action movies broadcast over the last fifty years and still making their way slowly through the galaxy, not to mention such pop music classics as * Sugar, Sugar * and * In the Year 2525 * . Forget about Shakespeare and Beethoven. They’re gonna judge us by * I Love Lucy, * * Dirty Harry * and the Bay City Rollers.
Well, Pioneer 10 & 11 and Voyager 1 & 2 will still be cursing the stars with their phonograph records full of pictures and music. They will be about 12,000 light years Earth by that time.
That might not be so far off. How long would hard plastic last if it was encased in sediments? I know it can degrade eventually, and 100 million years is an extremely long time, but I think some evidence of plastics would remain. And since plastic isn’t a natural substance, aliens could assume there was a civilization.
The big thing to remember in this kind of speculation is that the Erath isn’t stable. It really isn’t. Get a geo survey map and try to find some surface rocks that are 100 million years old. It’s extremely rare and where they do exist it’s because they have eroded back to that date, not because the same surface rocks exist in the same place undisturbed.
And that’s the real reason why remains will be uncommon. In that time the very rocks the cities stand on will have eroded away into the oceans, or been lifted up and turned sideways by earthquakes, or capped with hundreds of metres of mud, or covered in flowing lava. It might seem stable to us but the surface of the Earth isn’t stable and it doesn’t sit still for millions of years like that. It’s a big difference talking about neolithic postholes 50, 0000 years old and rocks tens of millions of years old.
What would be left would be essentially fossils. And as other have said, there would probably be enough of them to give us away. Fossilised pieces of technology really would remain, and it’s tough to assign any explanation to a fossilised PC or cellphone other than technological. It just doesn’t look even vaguely organic.
So yeah, there would be evidence that our civilisation had existed, but it wouldn’t be immediately obvious and it would take a lot of searching. Inhabitants of Earth probably wouldn’t reconstruct the evidence casually any more than they reconstructed the evidence of the dinosaurs. And we’re probably talking about the same amount of evidence as there was for the dinos.
As I mentioned earlier, IMO the dead giveaway would be the sudden diffusion of many different species (livestock, pets, crops, pests, etc in addition to humans themselves) all over the world within the same eyeblink of geologic time.
I can see the future paleontologists debating which of those species created the civilization that carried them around the world…
