There is a concept/thought experiement: we have come from stone tools to radio telescopes in < 20K years. The Saurian Hypothesis posits that dinosaurs had members that were as intelligent as we or more. After all this time most evidence would be destroyed. This would be less that 1/100000 of the time dinosaurs were on earth and it's a bummer for them that the asteroid came; or that they opened the asteroid dimension. The en.wikipedia.org/wiki/Silurian_hypothesis is on and Joe Scott to get a taste of the Silurian hypothesis. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-xtJ49gXWwA0.html