In Chernobyl, they’ve found bacteria and fungus that eat the radioactive decay from what remains of the power plant. If these guys can digest that stuff, I’m sure styrofoam will be no problem as a food source. It’s plentiful and tastes better than rice cakes.
However, come to think of it, I’ve never seen a rice cake go moldy either.
Space is big. Really big. And so is Mars. For the extraterrestrial visitors to notice the stuff on Mars, they would have to look really, really hard. Finding a flyspeck on a football pitch would be much easier than discovering random pieces of metal, half buried by sandstorms, on a lifeless rock that would be of minimal interest in the first place. In ten thousand years, those Mars probes will be inactive, powerless, not transmitting any signals, their tracks scoured away by the wind. The visitors will simply not have occasion to stumble across them.
Like Voyagers and New Horizon have literally zillions of miles of nothing around them in all directions. In a hundred years, with inert RTGs, they will be no more consequential than any other thing out there. No one will notice them.
Terran satellites, on the other hand, are fairly stable. There are scores of satellites in the 22000 mile geosynchronous band, which seems like a pretty darn stable place to be. I could see those things staying up there for millennia. And that is a specific area that technological visitors would certainly take a look at.
There might not be anything recognizable left on the surface, but buried underground a lot of that stuff will last forever. Without oxygen or specific conditions for anaerobic bacteria to thrive in it’s just going to get compressed. Water leaching through it may fossilize it.
Well, maybe not ‘forever’, but certainly for a long time. I remember reading about some archeologists looking at a US landfill somewhere that had been discontinued in the 60’s, and they were finding news paper and even meat and other perishable items still sitting there decades later. In fact, their findings helped shape some of the new landfills so that they are better at decomposing stuff in the future.
I imagine that there would be a lot of examples of things left behind that for one reason or another would still be recognizable. Even if we are talking about odds like 1 in 10 million or even 1 in a billion there are hundreds of billions of human artifacts on the Earth. Our alien archeologists should have plenty to find and study. What they make of it, however, would be interesting to see.
I participated in the opening of a desert landfill. It smelled like hell, but the stuff in it was pretty well preserved. The stuff was only 30 years old, but things like newspapers were perfectly legible–discolored, but intact. Nothing appeared to have decayed much at all. And isn’t there decayed organic sludge inside fossilized dinosaur bones? The question isn’t whether there would be discoverable traces of humanity, it’s whether there would be easily visible signs of our existence.
I think the only visible signs (if we are talking large scale structures) would be basically tells…oddly shaped hills or formations that are too regular looking. Though the structures would rot away in most cases, I think that the outlines would still be there for things like roads or cities. Certainly if the aliens used satellite imagery and ground penetrating radar or their equivalent tech they would see quite a bit on the 10k time scale. A million years? That’s more problematic, but I’m fairly sure that there would be artifacts, if not large scale structures or the remnants of them on that time scale.
And yes, soft tissue has been found in some dinosaur remains, which indicates that even on very long time scales it’s possible even something as fragile as soft tissue can survive. It would be interesting to see the aliens finding some odd bit of human tech or culture and how they would interpret it.
There is an excellent book on this subject (and relevant to this entire thread) called The Earth After Us: What Humans Will Leave in the Rocks, by geologist Jan Zalasiewicz. The upshot is that, a hundred million years in the future, alien geologists and paleontologists will probably notice a global extinction event, and there’s a decent chance they’ll find evidence of global climate change around this time, but direct evidence of the human species will be chancier.
It comes down to how most tectonic surfaces are treadmills of generation and destruction. If they’re above the water line, they erode. If they’re below the water line, most of them eventually get melted in a subduction zone.
It turns out the best chance for physical preservation of human artifacts would be cities near the mouth of a large river with lots of sediment discharge at a tectonically quiet (for now) continental margin – the author mentions New Orleans – but even then, many needles have to be thread for long-term preservation, then uplifting, and then partial exposure through erosion.
One good candidate for survival is stone tools- handaxes and so on. They have survived a couple of million years already; they should survive a bit longer. Similar artifacts might survive, perhaps in slightly worse condition- obsidian letter-openers, coke bottles, microscope lenses…
There would also be a wave of simultaneous appearances of invasive species in regions distant from their previous habitats – a sufficiently extensive pattern of that (if enough of them survive long-term) would point to a global civilization.
For a humorous take on that: http://www.amazon.com/Motel-Mysteries-David-Macaulay/dp/0395284252/ref=sr_1_1?s=books&ie=UTF8&qid=1452475678&sr=1-1&keywords=motel+mysteries
Yes, absolutely…the author also focuses on this, and I should have mentioned it.
Great cite! From the author of the classics “Castle,” “Pyramid,” etc.
Since reading that as a kid, I’ve often thought about using my toilet seat for ornamental headgear.
LOL. And I’m sure you’d look fabulous in it.
Too bad we’ve been opening up our own landfills. You said dessert landfill and I immediately thought of those Atari E.T - The Extraterrestrial game cartridges and what our alien friends would think of those if we didn’t dig them up.
That was a desert landfill. A dessert landfill would be much sweeter.
There’s a chocolate chip cookie landfill not far from here. Now if only it would rain milk…
There are loads more down there–the dig only brought up a fraction of what was dumped. However, most of the cartridges are not, in fact, E.T. games. They were unplayable though.