4 ms·

> a civilization like this would not leave a trace on the geological record. At all? Like nothing that would be observable 50M years later?

• brabel 2y ago
  Nothing built with "usual" materials we have, mostly because of the constant movements and subduction of tectonic plates, as well as volcanism and erosion. Think about something you believe would last 50 million years. I am sure someone will be able to point out how and why that would just disappear after such ridiculous amount of time.
  • red_admiral 2y ago
    Aren't the oldest fossils we know of assumed to be something like 500 million years old? Or you could try leaving particular "signatures" of radioactive elements. Not ones with a short half-life, obviously, but xenon-124 lasts pretty long, tellurium-128 will survive anything except the heat death of the universe, and there's a few others like that.
    • yencabulator 2y ago
      Sure, how many >300 million year old fossils have we found related to how many animals lived at that time, over that span of time? The problem is many methods might work -- literally you accidentally falling on a trip to Florida might work -- but the probability can be very low.