What if Humans Are NOT Earth's First Civilization? | Silurian Hypothesis

Sign Up on Patreon to get access to the Space Time Discord!

We’re almost certainly the first technological civilization on Earth. But what if we’re not? We are. Although how sure are we, really? The Silurian hypothesis, which asks whether pre-human industrial civilizations might have existed.

Check out the Space Time Merch Store

Sign up for the mailing list to get episode notifications and hear special announcements!

Hosted by Matt O'Dowd
Written by Christopher Pollack & Matt O'Dowd
Post Production by Leonardo Scholzer, Yago Ballarini & Stephanie Faria
Directed by Andrew Kornhaber
Associate Producer: Bahar Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber
Executive in Charge for PBS: Maribel Lopez
Director of Programming for PBS: Gabrielle Ewing
Assistant Director of Programming for PBS: John Campbell

Spacetime is produced by Kornhaber Brown for PBS Digital Studios.
This program is produced by Kornhaber Brown, which is solely responsible for its content.
© 2023 PBS. All rights reserved.

Space Time Was Made Possible In Part By:

Big Bang Sponsors
Bryce Fort
Peter Barrett
David Neumann
Sean Maddox
Alexander Tamas
Morgan Hough
Juan Benet
Vinnie Falco
Fabrice Eap
Mark Rosenthal

Quasar Sponsors
Glenn Sugden
Alex Kern
Ethan Cohen
Stephen Wilcox
Mark Heising

Hypernova Sponsors
Stephen Spidle
Chris Webb
David Giltinan
Ivari Tölp
Zachary Wilson
Kenneth See
Gregory Forfa
Bradley Voorhees
Scott Gorlick
Paul Stehr-Green
Ben Delo
Scott Gray
Антон Кочков
Robert Ilardi
John R. Slavik
Donal Botkin
Edmund Fokschaner
Chuck Zegar
Jordan Young
Daniel Muzquiz

Gamma Ray Burst Sponsors
Robert DeChellis
Tomaz Lovsin
Anthony Leon
Billy Holland
Leonardo Schulthais Senna
Lori Ferris
Dennis Van Hoof
Koen Wilde
Nicolas Katsantonis
Piotr Sarnicki
Massimiliano Pala
Thomas Nielson
Joe Pavlovic
Justin Lloyd
Chuck Lukaszewski
Cole B Combs
Andrea Galvagni
Jerry Thomas
Nikhil Sharma
Ryan Moser
John Anderson
Bradley Ulis
Craig Falls
Kane Holbrook
Ross Story
teng guo
Mason Dillon
Harsh Khandhadia
Susan Albee
Matt Quinn
Michael Lev
Terje Vold
James Trimmier
Jeremy Soller
Paul Wood
Joe Moreira
Kent Durham
jim bartosh
Ramon Nogueira
The Mad Mechanic
John H. Austin, Jr.
Diana S Poljar
Faraz Khan
Almog Cohen
Daniel Jennings
Russ Creech
Jeremy Reed
David Johnston
Michael Barton
Isaac Suttell
Oliver Flanagan
Bleys Goodson
Mark Delagasse
Mark Daniel Cohen
Shane Calimlim
Tybie Fitzhugh
Eric Kiebler
Craig Stonaha
Frederic Simon
John Robinson
Jim Hudson
Alex Gan
David Barnholdt
John Funai
Bradley Jenkins
Vlad Shipulin
Cody Brumfield
Thomas Dougherty
King Zeckendorff
Dan Warren
Joseph Salomone
Patrick Sutton

[enotdetcelfer]

This is why we need to build a pyramid on the moon... you know future civilizations will be like, pyramids or it didn't happen.

[sethmaki]

Reminds me of the Star Trek: Voyager episode "Distant Origin" where the hero ship happens upon an ancient civilization on the other side of the galaxy that descended from hadrosaurs that left Earth 70 million years ago.

[Sir_Typesalot]

„They‘re already here, aren’t they?“

- „THEY have been here long before us, Mr. Mulder.“

[BoyoLoco-rdfi]

Youtube comments can be weirdly confident about what happened an unimaginable timescale ago

[stevelyman]

"The Brain Eaters, " a 1958 horror film had a plot that revolved around an insect civilization from the Carboniferous creating a capsule to escape their refuge from deep underground. Also notable for featuring a pre-Trek Leonard Nimoy.

[pugofwarbr]

this reminds me of the Lovecraft's stories, basically Earth was invaded by different civilizations on the course of millions of years, all them sooner of later became extincts, or devolved, or literally just ghosts remains.

[davidtal]

i really enjoy these episodes that dont contain overly complex math and phsyics that i cant remotely understand. this was interesting, and fun. thank you.

[schfiftyfive]

"LIZZID PEEPOL"
-Hecklefish

[jeffk]

This is the proper way to debunk a conspiracy. Don’t strawman the argument or attack the proponents, steelman the argument and actually try to take it seriously, while looking for contradictions that imply falsehood

[Gnomezonbacon]

There was an episode of Star Trek Voyager about this. A dinosaur civ escaped before the asteroid hit and drifted around the galaxy for millions of years until a ship from the same homeworld stumbled into them on the other side of the galaxy.

[taliaeategg]

Kendricks been really quiet since the drake equation dropped

[SF-fblv]

I think Silurian Hypothesis should be boiled down to: "Due to subduction, records of surface phenomena will be obscured over millennia" instead of the current: "an Industrial Civilization may have existed before humans existed". It is like modifying the belief that "A teapot might be orbiting Earth" to "It would be difficult to detect something as small as a teapot orbiting Earth".

[DanielVerberne]

This fascinating concept brings to mind the famous sci-fi classic 'Nightfall' by Isaac Asimov and Robert Silverberg. In Nightfall, an alien race lives on a world that features not one but several suns. Each sun is up and visible at some part of the time each day and so the concept of 'darkness' is unknown and therefore terrifying to these aliens.

In the story, astronomers make a prediction that a full eclipse will occur in the near future, exposing the alien civilisation to complete darkness. It is predicted that most of the aliens will go insane from the experience. Meanwhile in parallel to this storyline, the alien equivalent of geologists are exploring a dig site that uncover something shocking - a layer of carbon and ash buried under the current layer of habitation. The analysis suggest that the ash represents mass fires and destruction - of a previous 'cycle' of civilisation of that alien race. Further digs reveal something even more shocking - an undeniable pattern of wholesale civilisation destruction occurring with a definite period; over and over. It is eventually realised that the current civilisation of aliens on that planet is now 'almost due' for another collapse - and it looks like the forthcoming ultra-rare eclipse and descent into darkness may be the root of all of this.

In short, Nightfall as a story contained a seed of the Silurian Hypothesis - what if our current 'advanced' civilisation isn't the first and indeed perhaps only represents the apogee of this particular 'instance' of human civilisation? Now I don't think there's any substance to that idea here on Earth, but nor do I know for sure either.

[Realistic_Management]

This is why I love PBS Spacetime. They’ll cover cutting edge physics topics one day, and then give a fair look at far flung topics like the Silurian hypothesis the next. Fantastic work.

[pastorpresent]

I think the one who should take a bow here is the one who wrote the script for this video. Very well done! I was somewhat convinced that there had been previous ancient civilizations. But you dealt with all the issues I could think of in a way that was compelling.

[docnelson]

An excellent discussion of an interesting hypothesis that many dismiss as too speculative despite, as Matt points out, is a valuable exercise for helping us understand so many questions about life on Earth and elsewhere. A marvellous channel.

[senatorchinchilla]

I love theories like this because they really explore the vastness of time and space.

[psantochi]

This whole episode sounds like a bar conversation after a scientific conference. A lot of fun!

[davidcashin]

One thing I love about these videos is that they do not gloss over the hypothetical nature of the question and that they rationally frame that we are forming hypotheses to be tested or in the case of geology searched for and sampled.

[GSPV]

Appreciate all of you at PBS Spacetime, your efforts (shoutouts to the animators & editors.) I also appreciate the community here.