
The Silurian Hypothesis - vo2maxer
https://fermatslibrary.com/s/the-silurian-hypothesis-would-it-be-possible-to-detect-an-industrial-civilization-in-the-geological-record
======
temporaryvector
I don't have time to read the entire article right now, but after skimming it,
it seems to focus on what we might find but not on what's not there.

Focusing on Earth right now, if human civilization were to go extinct in the
near future, whatever comes after us will have a much harder time getting to
an industrial civilization (or maybe any civilization) because we have used up
a lot of non-renewable resources that aren't ever coming back. Namely, things
like abundant and easily accessible coal and oil. There's also things surface
metal deposits (tin, copper, iron, etc) which are essential for making those
first steps. Granted, we, as a civilization, have placed a lot of metal on the
surface but it's scattered all over and I have no idea how much of it will be
usable by the roach-people that come millions of years after us with no prior
knowledge.

Still, all of that aside, the fact that we have coal today strikes me as a
pretty convincing argument that there was no industrial civilization before
us. It doesn't rule it out entirely, of course. I can imagine an industrial
civilization without coal or oil, but I do have to stretch my imagination
farther.

~~~
gnomewascool
On geological time-scales (tens of millions of years) fossil fuels will be
replenished. In fact the paper presents a speculative, putative mechanism by
which an industrial civilisation may inadvertently help _provide_ these
resources for future civilisations:

> [...] the prior industrial activity would have actually given rise to the
> potential for future industry via their own demise.

See page "148", mid-way through the second column for details. (It's a shame
that Fermat's Library doesn't provide an interface for deep-linking parts of
the article.)

On a time-scale of thousands of years to (probably) single-digit millions of
years, you're almost certainly right, though.

~~~
roenxi
Mmm. Maybe. There is a plausible theory [0] that our coal deposits came from
the era between when plants learned to produce lignin but bacteria didn't know
how to break it down.

Given that lignin eating bacteria are now quite common, it is unlikely coal
seams will form of the same quantity and quality.

[0]
[https://en.wikipedia.org/wiki/Coal#Formation](https://en.wikipedia.org/wiki/Coal#Formation)

~~~
s1artibartfast
I Think there is some confusion between coal formation rate and coal formation
volume. My understanding is that more coal has been formed since the
cretaceous than during the cretaceous.

Figure 1 in the link below provides a good demonstration of north american
coal formation over time.

[https://www.pnas.org/content/113/9/2442](https://www.pnas.org/content/113/9/2442)

------
jp57
Unpopular opinion(?): Fermat's Library makes the experience of reading papers
worse. This and many other linked papers I see there seem interesting, but I'm
not interested reading in the marginalia, or logging in, or signing up for
their mailing list to receive a paper every week.

What I would like to do is download the PDF and read it on my iPad, or even
print it out. But if that's possible, I haven't been able to find the link or
button to do it.

~~~
zgniatacz
[https://www.cambridge.org/core/journals/international-
journa...](https://www.cambridge.org/core/journals/international-journal-of-
astrobiology/article/silurian-hypothesis-would-it-be-possible-to-detect-an-
industrial-civilization-in-the-geological-
record/77818514AA6907750B8F4339F7C70EC6)

------
Iv
That article is full of interesting factoids. My favorite:

> What might distinguish naturally occurring biomarkers from synthetics might
> be the chirality of the molecules. Most total synthesis pathways do not
> discriminate between D- and L-chirality, while biological processes are
> almost exclusively monochiral

------
kijin
The article mentions ocean anoxic events as possible markers of civilizations
that ended in disaster. But the opposite might be even more fascinating to
ponder.

What if there was a civilization ~2 billion years ago that thrived in the
oxygen-poor environment, who accidentally unleashed cyanobacteria upon the
world? Kinda like how we're recklessly dumping CO2 into the atmosphere, but on
a much grander scale. Life would have had to re-evolve from the unicellular
stage, and all evidence of the oxygen-dumping civilization would have been
erased by geological forces by now.

------
lifeisstillgood
The article refers to an interesting paradox:

>>> However, the longer a civilization lasts, the moresustainable its
practices would need to have become in order tosurvive

~~~
joe_the_user
This might explain "Fermi's paradox".

It seems like all the models of extraterrestrial life being visible rest on
the assumption that this life would be the product of the equivalent our
present rate of growth continuing and quickly reaching cosmic scales. If
that's basically impossible and intelligent life that survives is living
sustainably, then we wouldn't have star-enfolding Dyson spheres and similar
things that are detectable at cosmic distances.

~~~
joe_the_user
Or, another possibility is that the sustainability of continuous short-term
exponential growth varies from location to location but it's not going to be
infinitely sustainable anywhere. Thus we might see blips but we won't see a
"colonized galaxy".

IE, the societies that keep up exponential growth to a cosmic scale probably
still won't have solved the problem of indefinite exponential growth. We know
the ways that, on Earth, the increase in human knowledge and productive
produces unintended consequences with significant chances of destroying us. We
don't yet know similar mechanism in space but it seems quite plausible these
would exist. Dyson spheres aren't even gravitationally stable (see Larry
Niven's Ring World series).

------
nickhalfasleep
I wonder if you might find evidence in near-earth orbits.

Would a geosynchronous satellite stay in place after 400 m.y.a? Or a descent
stage of a moon lander, perforated by impacts, from a Troodon?

~~~
nickhalfasleep
The worst part of this, the realization that the K-T boundary was the fallout
of a nuclear exchange.

~~~
sonofgod
We are pretty sure KT was caused by a giant asteroid. Maybe the space
Silurians redirected it into Earth? (Not serious)

------
thrower123
The question would probably hinge on whether they were given to building
cyclopean architecture. If the Egyptians were just content to build mudbrick
cities, rather than erecting pyramids, colossal stone statues, stelae,
obelisks, and the like, they would be much harder to detect.

~~~
marcus_holmes
On geological timescales, that makes no odds. Nothing built of stone will
survive natural weathering over millions of years. Mountains don't survive it.

Concrete won't survive it either, even modern reinforced concrete (actually,
our modern reinforced concrete won't last as long as the concrete the Romans
used, and their concrete might actually outlive lots of ours).

~~~
buzzkillington
Pyramids made of gold then.

------
marcus_holmes
I'm curious about the change in metal availability. From the paper

"The Paleocene–Eocene thermal maximum (PETM)" ... "Additionally, many metal
abundances (including V,Zn, Mo, Cr) spiked during the event "

How does metal availability increase like this?

Obviously, our industry will increase metal availability, because we spend
lots of time and energy digging through other geological layers and dragging
all their metal deposits into ours. But how could this happen naturally?

~~~
wolfram74
On a global, semi-uniform scale? Not sure. But locally, maybe intense
vulcanism? The Siberian Traps[1] were bringing up material from below ground
on a scale that's kind of hard to fathom.

[1][https://en.wikipedia.org/wiki/Siberian_Traps](https://en.wikipedia.org/wiki/Siberian_Traps)

~~~
marcus_holmes
that makes sense, though that was a 2-million-year event, so maybe something
smaller ;)

------
zyxzevn
Check [http://geopolymer.org](http://geopolymer.org) About a concrete
technology that probably existed worldwide.

Because a lot of these structures are very old and some are even under water,
I think that they likely existed during the ice-age. Later cultures like the
Incas build on top of these huge structures.

~~~
emmelaich
Interesting, but the Prof Joseph Davidovits sounds like he is on the fringe of
theories with respect to these stones.

Paper via wikipedia:
[https://www.tandfonline.com/doi/abs/10.5408/0022-1368-40.1.2...](https://www.tandfonline.com/doi/abs/10.5408/0022-1368-40.1.25?journalCode=ujge19)

> _It is not easy to give a geological education to a brilliant and determined
> chemist._

Savage

------
tudorw
If you enjoy thinking about epic timescales I recommend Olaf Stapledon's 'Last
and First Men: A Story of the Near and Far Future' fairly outdated, heavy
going, but unique.

------
jajag
_If_ there is anything more to UFOs than just mass hysteria and wishful
thinking, then I've always thought it much more likely that they are from a
previous industrial civilization here on earth than being extraterrestrial -
the PETM from 56 million years ago would be a good candidate for their home
time.

------
tzfld
>If an industrial civilization had existed on Earth many millions of years
prior to our own era,what traces would it have left

What about space based traces? Abandoned spacecrafts, which can easily remain
preserved millions of years.

------
peter_d_sherman
Wikipedia:

[https://en.wikipedia.org/wiki/Silurian_hypothesis](https://en.wikipedia.org/wiki/Silurian_hypothesis)

"The Silurian hypothesis is a thought experiment[1] which assesses modern
science's ability to detect evidence of a prior advanced civilization, perhaps
several million years ago. In a 2018 paper, Adam Frank, an astrophysicist at
the University of Rochester, and Gavin Schmidt, director of the NASA Goddard
Institute, imagined an advanced civilization before humans and pondered
whether it would "be possible to detect an industrial civilization in the
geological record".[2]"

The geological record is an interesting possibility -- but a better question
might be:

"If you wanted to preserve the record of an advanced civilization across super
long periods of time -- how would you do it?"

I've thought about this question long and hard.

Stone buildings seem to last no more than 10,000 years, and by the time they
are discovered, they have usually been ransacked by grave-robbers and
treasure-hunters:

[https://en.wikipedia.org/wiki/List_of_oldest_known_surviving...](https://en.wikipedia.org/wiki/List_of_oldest_known_surviving_buildings)

Satellites would fall out of orbit by that time, and I don't know any piece of
high-technology that has had an uptime of more than maybe 20 years... the more
complex something is -- the more prone to failure it becomes.

A USB Drive from an advanced civilization in our past -- just wouldn't make it
through to today...

So here's my idea:

Why not put the knowledge of an advanced civilization, into the DNA of some
plants? 98% of DNA is unused, aka, non-coding DNA, aka, "Junk DNA":

[https://en.wikipedia.org/wiki/Non-
coding_DNA](https://en.wikipedia.org/wiki/Non-coding_DNA)

So... why not put it there?

But... there's a problem! DNA is going to shift around a bit over time, so
we're going to need to account for that! (We'd accomplish this by replicating
the same information over and over at least several times).

So with all of that in mind -- here is my top candidate as one potential
carrier of that information:

[https://www.sciencemag.org/news/2010/10/scienceshot-
biggest-...](https://www.sciencemag.org/news/2010/10/scienceshot-biggest-
genome-ever)

The Flowering Plant: Paris Japonica

Why?

Its DNA apparently contains 130 billion base pairs... that's a lot of room for
information, and replication of that information!

Maybe there's something in there, or then again, maybe I'm a crackpot!

History will tell! <g>

But, that would be my top candidate for where that information might be, if it
exists anywhere at all...

~~~
vhvjkyhkogvv
I'd build something that's impossible to miss, and hard to destroy. A stone
henge on the moon maybe.

~~~
twic
Or just a moon.

------
Iv
A fascinating read!

