Could very ancient advanced intelligent terrestrial life have existed?
This article is about Fossils
Within it they mention that 3.5 billion years ago the Earth was sterilized by a cosmic asteroid bombardment.
Within the past few billion years could another race of highly advanced intelligent life have lived here and become extinct leaving no trace?
If so would we have found clues to such an existence? Where would we look for 2–4 billion year old technology?
Could the mantle have eaten Earth’s surface leaving nothing?
Could the creatures who became intelligent have seen the devastation coming and left with their stuff?