Could Earth have had advanced civilizations before humans?

No known evidence shows an advanced civilization on Earth before humans.

Scientists have still explored the idea, especially through the Silurian Hypothesis: if an industrial civilization had existed tens of millions of years ago, would we be able to detect it today? The challenge is that Earth erases evidence fast over geologic time. Plate tectonics, erosion, and glaciation would destroy most ruins, metals, and plastics.

What might remain are chemical and geological clues:

• unusual isotope shifts in rocks
• long-lasting synthetic chemicals
• radioactive anomalies
• sudden changes in fossils or extinction patterns

Past events like the PETM are real examples of dramatic climate shifts, but they are best explained by natural causes such as volcanism or impacts, not lost industry.

So the short answer is: it’s a fascinating possibility to test, but there’s no evidence yet that advanced pre-human civilizations ever existed on Earth.