Here’s something that’s been kicking around the back of my mind for a while.
In a hypothetical scenario where the human race is wiped out, but without causing significant damage to all the bits of human infrastructure scattered around the planet, how long will it take before there’s no evidence that we were here as an (intelligent) species? Assuming, of course, that there’s no ‘Armageddon’ style impact, and ignoring, for the moment, the various artifacts that we’ve left on the Moon and in orbit.
The iron mines in northern Minnesota were dug in rock that’s been stable for a billion years or more. The holes may fill in before another billion years pass, but they won’t fill in with the same stuff as was there originally.
Welcome to the SDMB, nik. A question very similar to yours was asked about a week ago, so I’ll close this thread and direct further comment to the earlier one: Traces of humanity- -after 10,000 years?