Even 1 million years is enough to erase almost all signs of a technological civilization. But terrestrial life exists for 4 billion years. This allows for many attempts.
I’d dispute this geologically. Depleted oil reserves, microplastics, and nuclear isotopes come to mind.
I generally agree, but there is possibility for small tech civs: ancient Greeks were making mechanical computers, simple programmable machines, steam power, etc, while at populations below 10 mln, while occupying territories not much larger than the current Greece. Very easy to miss such a civ in the geological record.
I’d dispute this geologically. Depleted oil reserves, microplastics, and nuclear isotopes come to mind.
I generally agree, but there is possibility for small tech civs:
ancient Greeks were making mechanical computers, simple programmable machines, steam power, etc, while at populations below 10 mln, while occupying territories not much larger than the current Greece.
Very easy to miss such a civ in the geological record.