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If it were more than 65 million years ago there would be no evidence due to plate tectonics destroying all evidence. Still could be on the moon or another plan
by MR4D 3y ago
If it were more than 65 million years ago there would be no evidence due to plate tectonics destroying all evidence. Still could be on the moon or another planet though.
- paulryanrogers 3y agoWe still have fossilized bones that old and older. And even if they had corroding tools there would likely be cast fossils proving their existence.
- flangola7 3y agoWe have fossils of cyanobacteria from 3 billion years ago. There's plenty of dinosaur fossils that are 100+ million years old. We definitely could have found something.
- Barrin92 3y agoThere would be no evidence on the surface of the earth, but just as there's characteristic fossil layers in the ground there would be evidence in the sediment. Right now about 30 billion tons of concrete are used by our species every year. If there were industrial civilizations of that scale, you'd have a whole stratum of very obvious artificial origin between the rocks. Also some leftovers of the nuclear industry. Enriched Uranium does not occur in nature but U235 has a half-life of about 700 million years. So remnants of our nuclear activity will be detectable for a long time.