Silurian hypothesis

The Silurian hypothesis is a thought experiment which assesses the ability of modern science to detect evidence of a prior advanced civilization, perhaps several million years ago. The most probable indications of such a civilization might be carbon, radioactive elements or temperature variation. The name "Silurian" was derived from a sapient species in the BBC science fiction series Doctor Who, who had established an advanced civilization prior to humanity. Astrophysicist Adam Frank and climate scientist Gavin Schmidt proposed the "Silurian Hypothesis" in a 2018 paper which explored the possibility of detecting an advanced pre-human civilization in the geological record. They argued that finding direct evidence such as technological artifacts would be unlikely because of the rarity of fossilization and Earth's exposed surface. Instead, researchers might find indirect evidence such as climate changes, anomalies in sediment, or traces of nuclear waste. The hypothesis also speculated that artifacts from past civilizations might be found on the Moon and Mars, where erosion and tectonic activity would be less likely to erase evidence. The concept of pre-human civilizations has been explored in popular culture, including novels, television shows, short stories, and video games. Jan Zalasiewicz, a geologist, paleontologist and emeritus professor at the University of Leicester in the UK, claims that Schmidt and Frank seriously underestimate how much evidence would be left by an advanced civilization.