IF AN ADVANCED CIVILISATION LIVED ON EARTH MILLIONS OF YEARS AGO, WOULD WE BE ABLE TO TELL?

Humans have long been fascinated by the possibility of finding technologically advanced beings elsewhere in the Universe, but what if such a civilisation had lived right here on Earth, long before humans evolved?

- DR CLAIRE ASHER

In 2018, physicist Prof Adam Frank and Dr Gavin Schmidt, a climate modeller, published a paper exploring whether modern scientists would be able to detect evidence of an advanced industrial civilisation that ended millions of years ago. They named this possibility the 'Silurian hypothesis', after an advanced reptilian race from the BBC's long-running sci-fi show Doctor Who.

They concluded that while it's extremely unlikely, evidence for such a civilisation might be hard to find. Focusing on a period between 400 million and 4 million years ago, the researchers pondered what evidence might be left behind by this hypothetical society.