The Silurian Hypothesis

[Caliga]

  seems somewhat appropriate for this.

This article came out about a year ago but I just came across it the other day.

THE SILURIAN HYPOTHESIS: HOW DO WE KNOW THAT HUMANS WERE THE FIRST CIVILIZATION ON EARTH?
BY ARISTOS GEORGIOU ON 4/18/18 AT 10:45 AM
Was There Civilization On Earth Before Humans?

What if another industrial civilization had existed on Earth tens of millions of years ago, long before humans, but all traces of it have now been lost?

While it may seem like an absurd idea, this thought experiment is the focus of a new scientific paper authored by Adam Frank, an astrophysicist from the University of Rochester, and Gavin Schmidt, director of the NASA Goddard Institute for Space Studies.

They have named the paper "The Silurian Hypothesis" after a fictional race of intelligent, bipedal reptiles from the British sci-fi series Doctor Who—known as the Silurians—that supposedly lived on Earth hundreds of millions of years ago.

In the study, which has been published in the International Journal of Astrobiology, Frank and Schmidt ask what traces human civilization would leave behind and how future scientists might find evidence of our existence.

The researchers looked at the likely geological fingerprint of the Anthropocene—a term used by many researchers to denote the current geological age in which human activity has been the primary influence on the climate and environment.

While the Anthropocene has not yet been officially classified as a distinct geological era, it is already clear that humans are having an impact on the geological record being laid down today, the authors wrote in the paper.

"We are already a geophysical force, and our presence is being recorded in carbon, oxygen and nitrogen isotopes, extinctions, extra sedimentation, spikes in heavy metals and synthetic chemicals (including plastics)," Schmidt told Newsweek.

The human burning of fossil fuels, for example, is already having an impact on the geological record, despite industrialization only beginning around 300 years ago. What's more, global warming, agriculture and the spread of synthetic pollutants are all making their mark.

So let's imagine that, perhaps, some other species on Earth rose briefly to civilization millions of years ago, would there be any traces of them today, for example, fossils or the remains of buildings?

"Possibly," Schmidt said, "but it might also be that all such traces have been ground to dust and that the only remaining traces are in the more subtle perturbations in geochemistry." In addition, "fossilization is extremely rare and very partial, so evidence could easily have been missed," especially if a civilization had lasted just a few thousand or tens of thousands of years, much like our own.

"We know early Mars and, perhaps, early Venus were more habitable than they are now, and conceivably we will one day drill through the geological sediments there, too," Schmidt said in the statement. "This helps us think about what we should be looking for."

Discuss.

I read another article on this subject suggesting the most likely place to find evidence of past civilizations would actually be on the moon or in Earth's orbit, assuming the civilization made it to space before going extinct.

[garbon]

Discuss.

Fuck off?

[Caliga]

I feel like Tim's response will be a bit more positive.

[mongers]

It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?

[Valmy]

It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?

This.

[Syt]

Read about this a while ago, and it's an interesting hypothetical/brain exercise as to what long term traces an advanced civilization would leave behind. Whereas in sci-fi you often have remnants of civilization that are well preserved hundreds of thousands and sometimes millions of years later.

[garbon]

Battlestar Galactica

[Admiral Yi]

I'm with mongers.  Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now.  Did the Silurians never advance past the technology of wood-working?

[Caliga]

I'm with mongers.  Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now.  Did the Silurians never advance past the technology of wood-working?

I should probably have linked multiple articles that are more in-depth about the hypothesis to this thread, but in one of them with a more in-depth writeup about the original paper, it said that in fact plastic would break down over many millions of years, so while there wouldn't be a recognizable plastic bottle there might be odd chemical signatures indicating something unnatural was happening during whatever era this hypothetical civilization existed in.

[Caliga]

Read about this a while ago, and it's an interesting hypothetical/brain exercise as to what long term traces an advanced civilization would leave behind. Whereas in sci-fi you often have remnants of civilization that are well preserved hundreds of thousands and sometimes millions of years later.

Yeah.  I am not saying "I believe there were past civilizations" in posting the article, but the authors are trying to make the argument that suggesting so isn't a completely laughable idea like I would have thought prior to reading about the hypothesis.

[Grey Fox]

We don't. It's impossible to know.

[Josquius]

There's also the theory of ice age human pseduo civilization in areas that have since flooded.

All cool theories alas unlikely.

[Barrister]

It's ludicrous since we've now found huge numbers of dinosaur tracks across all the world, if these very ephemeral things can be preserved, how come we've not also seen indications of them or anyone else leaving traces of technology alongside those footprints in the sands of time?

But the dinosaurs existed for a ridiculously long period of time - over 100 million years, yet what we know of them is so very little.  Many known dinosaur species are known from only a single example found.  All of human civilization has only existed for a few thousand years, and our "modern" civilization only 1-200 - a geological blink of an eye.

But yeah, pretty unlikely.

[Razgovory]

I'm with mongers.  Plastic bottles sitting in land fills are going to be there beelions and beelions of years from now.  Did the Silurians never advance past the technology of wood-working?

Plastic bottles are biodegradable.  They are estimated last hundreds of years perhaps a few thousand in the right environment, but not billions.  If you were to look for a civilization that existed hundreds of millions of year ago your best bet would be checking layers of sedentary rock.  Human civilization produces a lot of weird chemicals that escape into the atmosphere.  Those will eventually settle to the ground, become part of the sediment and turn into stone.


EDIT:  Sedentary rock is like Sedimentary rock but lazier.

[Malthus]

If they were anything like us, they would have altered the landscape in easily-recognizable ways - for example, highway cuttings through solid bedrock. These would still be visible millions of years later.