A thought experiment plumbs archaeology and geology to ask whether our own species will leave a trace.
In the 1968 film
Planet of the Apes, a crew of human astronauts travels into the future and lands on an alien planet that a civilization of non-human primates inhabits. Only when the film's protagonist discovers a half-buried Statue of Liberty on the shore does he realize that this is not an alien world, but rather a future Earth dominated by a new species of intelligent apes that have outcompeted humans.
The scene is as provocative today as it was 55 years ago.
Homo sapiens, the futurists tell us, may one day be succeeded by another intelligent species. But
how do we know another intelligent species didn't come before us? After all, if civilization had also arisen from an earlier, now-extinct animal species, where are the ruins of its cities? If we found fossils of dinosaurs that lived tens of millions of years ago, we should also have found relics of tombs and temples built in the deep past.
In 2018, climatologist Gavin Schmidt and astrophysicist Adam Frank published an intriguing
paper in the
International Journal of Astrobiology called, "The Silurian hypothesis: Would it be possible to detect an industrial civilization in the geological record?" The title is derived from a
Doctor Who episode featuring a reptilian race known as the Silurians who gained intelligence before humans. The purpose of the Silurian hypothesis isn't to assert that another civilization came before us. Rather, it's a thought experiment to get us thinking about how we would know if a pre-human civilization once existed, a point that might be too subtle for some netizens in our age of
Ancient Aliens memes.
Schmidt and Frank acknowledge that paleontologists haven't uncovered fossilized evidence of pre-human civilizations — but that's the point. If a civilization thrived millions of years prior to us, its artifacts could have been destroyed.
Geological processes such as tectonic plate subduction and glaciation could easily erase evidence of ancient urbanization.
Comment: This kind of censorship and biased revision happens in our own time - and often to discredit great people - and its likely our understanding of our past is equally obscured by such actions: