If an advanced civilization existed on earth several million years ago, would we actually be able to detect that they were here? It may sound like conspiracy theorist bait, but a serious and balanced look at the question reveals a lot about geology, climate and the search for alien life. In this classic episode of the Stuff to Blow Your Mind podcast, Robert and Joe discuss the silurian hypothesis. (originally published 01/18/2022)See omnystudio.com/listener for privacy information.