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Suppose that due to nuclear warfare or some deadly disease, the entire human population of earth died off in the near future. All humans gone, but most of life survived, including domesticated animals. Obviously the wildlife will soon take over and slowly the evidence of humanity will start to disappear.

How long would it take for all evidence to disappear? I'm talking including satellites, the ISS etc would have to either escape our orbit or more likely collapse back onto earth, all structures to be vanished, all human-made things to be vanished. I'm fine if structures deep underground or on ocean floors survived, but nothing visible on ground should remain, and even stuff that's underground if it's not too much underground.

How long would it take? Would it at all be possible before the sun dies off?

EDIT: Supplementary Info

This is what I'm mainly concerned about, in bullet form to highlight.

  • How long would things like ISS and satellites take to collapse?
  • Things that take a long time to decompose like plastic.
  • Give it a few hundred million or even a billion years. Continents will have shifted, new mountains raised and the existing ones gone, would we still be able to see such long lasting creations of humanity?
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    $\begingroup$ My guess it could take forever to get rid of certain objects ...but the time will be limited by how fast material is covered and turned over into the hotter areas of the planet surface. That however can take very long too. And the other points in the other thread... $\endgroup$ – World Peace Aug 22 at 23:06
  • $\begingroup$ Added few new points. $\endgroup$ – Sach Aug 22 at 23:24
  • $\begingroup$ ISS will fall down within years, but high orbit satellites may remain in orbit for billions of years. $\endgroup$ – Alexander Aug 22 at 23:51
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    $\begingroup$ Radioactive waste would stay for quite a while. In fact, there was a fascinating documentary (that I can't locate right now) about people designing the warning signs for extremely hazardous and extremely long-lived waste. The design challenge is that it should be clear this is dangerous even if discovered 1000s of years in the future by people who might not have the same cultural reference as us. Or maybe not even humans. $\endgroup$ – VLAZ Aug 23 at 7:30
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Before the sun's expansion renders the surface of the Earth uninhabitable? Probably not. Most of the Earth's surface will be scoured clean of our influence pretty quickly, geologically speaking. However, there will remain islands of relative stability that will keep ruins of our civilization afloat for possibly hundreds of millions of years.

Consider the fact that although rare, we still find fairly complete dinosaur fossils. Bone from 200 million years ago is still recognizable. We make a lot more resilient and robust materials than bone. Often in huge quantities.

Those skeletal fossils survived that long by being buried and later exposed through erosion. This same process will occur for human ruins as well. They will be buried by the elements and then re-exposed at different rates in different locations, so its pretty much guaranteed that there will still be detectable ruins of structures somewhere at pretty much all times.

Most of what we've created won't last nearly that long though.

Coastal cities in the path of monsoons and hurricanes will be washed away within thousands of years. Same with big cities near major rivers as they twist and carve up the land.

Tens of millions of years are enough for life to rebound after anything we can do to it, and regrowth will breakdown and bury much of our societies efforts. But all of it?

Even continental drift and major natural disasters won't be able to scour everything away. Take a look at the wiki page for Cratons. Basically there are regions of stability within the continental plates that haven't changed much over the range of 500 million years. Surface erosion still occurs, but those regions won't likely be subducted deep beneath the crust... ever.

I would wager that remains of human establishments will have a decent chance at surviving for a VERY long time if they are situated in the right spot. If you want to go far enough ahead that detecting human civilization becomes very unlikely, 50-100 million years is probably a good bet.

Oh and satellites aren't really worth worrying about. One of our most stable orbits are graveyard orbits above geosynchronous orbits. Those will last for probably millions of years, but gravity and solar wind will eventually reclaim them as well. https://space.stackexchange.com/questions/18056/how-stable-are-satellites-in-a-graveyard-orbit

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    $\begingroup$ Worth noting that a dinosaur fossil is not composed of bone. It has undergone replacement, and is effectively a mineral cast of a former bone. This process will not necessarily work for many of our materials, and a lot of our junk will likely not end up in the correct environment for fossilisation anyway. $\endgroup$ – Arkenstein XII Aug 23 at 2:24
  • $\begingroup$ Thanks, fantastic reply! I'm thinking of a story on earth where after we perish, a future civilazation discovers our existence eventually. Wanted to know where in time it is best to place them and also what kind of thing they would be able to discover. $\endgroup$ – Sach Aug 23 at 20:40

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