
Was There a Civilization on Earth Before Humans? - wjSgoWPm5bWAhXB
https://www.theatlantic.com/science/archive/2018/04/are-we-earths-only-civilization/557180/
======
evanb
This reminds me of "The Habitable Epoch of the Early Universe"
[https://arxiv.org/abs/1312.0613](https://arxiv.org/abs/1312.0613) where it is
pointed out that for some time during cosmological evolution, the universe
would have been quite comfortable and rocky planets (if any existed) could
have had liquid water, with no need to be in a Goldilocks zone---the whole
universe was Goldilocks!

~~~
vatys
Back then everything would have also been so much closer together. The
universe could have been like one great bustling city. Perhaps, from that
perspective, we are already in some long-tail end-of-days time. Planets and
stars and galaxies are so far apart as to make travel difficult or impossible.

~~~
api
A science fiction story set in this time would be truly epic and beautiful.

~~~
Zuider
Space 1999 was a little like that. The premise was that the moon was blasted
out of the Solar system into interstellar space. Somehow, the doughty denizens
of Moonbase Alpha managed to encounter a new planet with intelligent life in
nearly every episode. That would have required the stars to be pretty close.

~~~
phs318u
Thanks for the reminder. I was completely OBSESSED with that show as a kid.

------
gpm
Would geostationary satellites from a previous civilization still be orbiting
in an approximately geostationary orbit? Or would they have been perturbed
enough that they would either exit earth orbit or impact earth? Or pounded
into dust by collisions?

If a previous civilization had metal-based moon landers, would we likely have
found them/found areas with an unlikely amount of metal on the moon? Or would
they have probably been obliterated by meteorites by now?

~~~
scottie_m
It depends? If the satellites used chemical rockets to produce stationkeeping
thrust then they’d be long gone, but if they used some exotic power source who
knows? If they had a good AI and power, there is no real limit on how long
they could stay in orbit. If they were using technology like ours they’d be
gone, but a hypothetical civilization might use exotic materials and power
sources that would stand the test of time.

For the moon thing, the above applies, but assuming that they were obliterated
we’d have to get pretty lucky to detect their remains. They could also be
totally intact because there would be essentially no weathering, they would
never be buried by shifting regolith, and so on.

~~~
ss2003
Anything sitting on the surface of the Moon would must likely completely
buried by regolith after roughly 2 million years. Every lunar day dust
particles are launched up from the surface only to fall back down at night.

~~~
gpm
Where do you get 2 million from? I.e. why not 20k or 200m?

------
interestica
Online version of the original paper:

"The Silurian hypothesis: would it be possible to detect an industrial
civilization in the geological record?"

[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/core-reader)

------
RikNieu
What interests me is the possibility of human civilizations between the Eemian
and last glacial maximum.

Any evidence of civilization from that period would either be hella deep under
the sea or obliterated by glacial expansion and retreat.

Homo sapiens have been here 300k years. I find it ridiculous to assume we only
started living in cities about 5-7000 years ago. Conveniently the period
immediately after the last rapid glacial retreat...

~~~
idoubtit
Homo sapiens started emigrating out of Africa 50k years ago. There is a small
incertitude on their emigration pattern (one wave or several), but it doesn't
matter here. If they had cities in Africa, it is very surprising we found no
trace of it, given the numerous archaeological expeditions everywhere in
Africa. There was no glaciation or sea change to destroy the evidences.

So according to your hypothesis, civilizations would have emerged from
hominids other than the homo sapiens, contrary to what we know about them. And
their cities would all be in the North of Europe, where the later glaciation
could hide some archaeological proofs. And we could not detect anything,
though an Ice age doesn't destroy anything.

I believe there is no fact to sustain that hypothesis, and many facts against
it.

~~~
Zuider
Don't forget that sea levels have risen some 120 meters since the end of the
last ice age. Given that civilizations tend to form close to the ocean, most
archeological evidence from tens of millennia ago, if such existed, would be
under water.

[http://theconversation.com/ancient-aboriginal-stories-
preser...](http://theconversation.com/ancient-aboriginal-stories-preserve-
history-of-a-rise-in-sea-level-36010)

------
brownbat
I know they are focused on markers of industrial civilizations, but the
prevalence of purpose built stone tools millions of years ago still blows my
mind a little.

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

~~~
all2
I always chuckle (and wonder at the veracity) when I find stuff like this:
[http://www.s8int.com/page8.html](http://www.s8int.com/page8.html)

It makes me wonder if the Ancient Aliens guy might be partially right.

------
zw123456
Perhaps dolphins are descendants of an ancient civilization, they evolved from
land animals [https://www.whalefacts.org/dolphin-
adaptations/](https://www.whalefacts.org/dolphin-adaptations/) about 50
million years ago. Just imagining here, but what if they had an industrialized
civilization that caused global warming that led to the PETM temperature rise,
their civilization declined and they had to adapt to a water world. Chuckle,
just a kooky thought I had after reading that article.

------
interestica
Alan Weisman's "The World Without Us" is an interesting book/thought
experiment that highlights just how fast the features and evidence of a
civilization might be erased through natural processes.

[https://www.goodreads.com/book/show/248787.The_World_Without...](https://www.goodreads.com/book/show/248787.The_World_Without_Us)

------
scottlegrand2
I'm actually more interested in if there was ever some sort of
extraterrestrial outpost on this planet in the past 1 billion years or so.

At that time scale, exploring the entire galaxy seems reasonably practical.
And stopping here to refuel and recuperate, not so unlikely, at least to me.

~~~
Noos
It's possible that the kind of extraterrestrial beings that could do any form
of FTL travel wouldn't even think in terms of "outposts" or "refuel." The task
is so immense that any technology capable of doing it would belong to a
society that would be gods to us. You're treating it like it would be them
cruising route 66, but for them, it could be something like us browsing a web
page or even just dreaming. I dream I want to be on earth, and here I am.

A lot of SF is really bad in they assume people will be the same and just
drive to different galaxies instead of drive to different states. But the
technology between the two is so huge that to get there would probably entail
a whole host of things that would transform them into something above us as
mayflies are to us. Not sure we'd even be able to tell if they left anything
or even stopped by.

~~~
repolfx
Possible - sure. But the default state should be to assume FTL aliens would
need to refuel.

Consider human civilisation circa 3000 years ago. People moved around on
horses, with carts. Roads were usually poor or non-existent. We are
incomparably advanced compared to back then. But:

• They had outposts for travellers and we have airports.

• They had to feed their horses, we have to refuel planes.

• They needed infrastructure to establish new towns and colonies. We do too
although the Earth being inconveniently full of cities often hides this fact.

Whilst the technology has changed enormously the fundamentals of travel and
colonisation haven't. If there's no refuelling process _at all ever_ then that
implies a violation of the conservation of energy laws anyway - even if you
only refuel once when a ship is newly built with some incredibly long lasting
energy source, that's still fueling.

~~~
NikkiA
That's somewhat of an anthropomorphic bias that may or may not hold true and
is impossible for us to determine until we meet said aliens.

------
speeq
> “Wait a second,” he said. “How do you know we’re the only time there’s been
> a civilization on our own planet?”

Imagine for a moment that we're Martians who managed to terraform Earth
because of some runaway climate catastrophe on Mars. That now, we're in the
early stages of repeating the same mistakes because of some extinction event
in the past that wiped out all of our prior history and knowledge.

~~~
skookumchuck
We're too similar to other life on earth for that to be credible.

~~~
interestica
We says we, the martians, didn't bring the other stuff with us?

~~~
pdonis
Life has been on Earth for at least 3.8 billion years. All of the life on
Earth today is descended from that original life. So if life on Earth
originally came from Mars, it would have had to do so at least 3.8 billion
years ago. But that's too close to the origin of the solar system as a whole
for it to be credible that an industrial civilization could have evolved on
Mars, caused a climate catastrophe, and then migrated to Earth.

~~~
landryraccoon
I don't think it's at all likely that life on Earth originated on Mars, but if
it did then there could have been cross pollination of microorganisms over
billions of years due to meteor impacts on both worlds throwing bits of crust
into space. In fact if we do find life on Mars at some point it wouldn't be
shocking if they are quite similar to bacteria found on Earth, since they
might just be descendants of earth bacteria carried over from the impact that
killed the dinosaurs.

~~~
pdonis
_> if it did then there could have been cross pollination of microorganisms
over billions of years_

I don't think this is consistent with DNA evidence, since such cross
pollination would be expected to show up as two sets of genetic lines of
descent with very different characteristics, since the environment of Mars is
very different from that of Earth; and we don't observer anything like that.
In fact, if life was evolving separately on Earth and Mars, it might not take
very long before the two lines of descent were not even compatible
genetically, meaning that genetic exchange would be impossible even if the
organisms were brought back together.

------
zmkzrk
This reminds me of the great short story "The Next Ten Billion Years" by John
Michael Greer: [http://archdruidmirror.blogspot.com/2017/06/the-next-ten-
bil...](http://archdruidmirror.blogspot.com/2017/06/the-next-ten-billion-
years.html?m=1)

~~~
martinpw
I liked this part from the "10000 years from now" section

 _believers in most traditional religions declare piously that the climate
changes of the last ten millennia are the results of human misbehavior, while
rationalists insist that this is all superstition and the climate changes have
perfectly natural causes._

------
ianai
My best reasoning for why we may conclude we’re the first civilization here is
the brain sizes seen before us in the fossil record other biological features.
You need big brains (in absolute volume), tool use, and culture forming. Of
course, just a guess.

~~~
raverbashing
Well, humans are not the ones with the biggest brain volume right now, but the
question stands: why other animals have not evolved bigger intelligence
before.

~~~
riffraff
in "the science of discworld"[0] this is touched upon through the nice example
of: T-Rex have been on the planet for a few million years, they were huge, and
we found a handful of their fossils. It is plausible (but not probable) that a
civilization of smart lizards evolved and disappeared in 100k years without
leaving any trace that we could find.

[0]
[https://en.wikipedia.org/wiki/The_Science_of_Discworld](https://en.wikipedia.org/wiki/The_Science_of_Discworld)

------
grawprog
This reminds me of a couple of old sci-fi series I read a long time ago.
Michael Moorcock's The Dancers at the End of time series about the last of
humanity that's become apathetic, decadent and godlike as all the stars die
around them and they come up with a plan to travel back in time and start
civilization earlier so humanity get get on its feet quicker, but discover
time is cyclical.

And another series, I wish I could read again but cannot remember the author
or titles, but it was about a world where civilization ended because we'd
genetically engineered ourselves and animals and everything into fairy tale
creatures who overran everything. The whole time it seems like it's set in the
future but it ends up the main characters become Adam and Eve and it implies
all our current mythology came from the society that genetically engineered
themselves out of existence.

------
vertline3
I think Neanderthals buried their dead and looked after their elderly @
shanidar cave site. Does this imply civilization?

~~~
sgt101
I think it implies a sophisticated culture, but people say that civilisations
are those cultures that create cities. It's a narrow conceptualisation, but it
goes hand in hand with the capabilities to create technologies that
significantly modify the environment in favour of the members of the culture
doing the city building. I don't think that anyone has found any indication of
Neanderthals using any sort of pottery, agriculture, domestication or
metalwork. This is not to say that they didn't have poetry and mathematics and
understandings of the world we would find interesting and unexpected, or that
they didn't have any of these technology - it's just that there is no evidence
at all that I am aware of.

------
wool_gather
> And then there’s all that plastic ... creating a layer that could persist
> for geological timescales.

Won't the plastic eventually turn back into oil, on geologic timescales? Or
are the conditions for that too specific to be relied on? Or am I completely
mistaken, and oil->plastic is basically one-way?

~~~
hyperman1
Ive heard there is too much oxygen in the air now for the original oil forming
processes

~~~
JumpCrisscross
> _there is too much oxygen in the air now for the original oil forming
> processes_

This is addressed in the article:

“...our work also opened up the speculative possibility that some planets
might have fossil-fuel-driven cycles of civilization building and collapse. If
a civilization uses fossil fuels, the climate change they trigger can lead to
a large decrease in ocean oxygen levels. These low oxygen levels (called ocean
anoxia) help trigger the conditions needed for making fossil fuels like oil
and coal in the first place.”

------
mycall
If there was a civilization 50 million years ago, I would think some parallel
species or genus would continue that DNA lineage to this day.

~~~
viscanti
Maybe Humans?

------
totemandtoken
Somewhat incidentally, I was watching a Wisecrack episode on the philosophy of
Tolkien which seemed to imply that his middle-earth universe was meant to be
read as preceding our own history [0]. Following in that vein, I wonder what a
high fantasy story that used prehistoric motifs would be like. Not a sci-fi
story, actual fantasy. Instead of a high fantasy with elves and hobbits, maybe
one with neanderthals and cro-magnons, but show them as having advanced,
competing civilizations to homo sapiens. Maybe instead of increasing technical
progress, we see primitive technologies evolve into living things like plants
and animals. "Every sufficiently advanced civilization is indistinguishable
from nature" as someone once wrote. Idk, I guess this doesn't add to the
discussion, but it's stimulating to say the least.

[0] [https://www.youtube.com/watch?v=_-sTbaH-
aA0](https://www.youtube.com/watch?v=_-sTbaH-aA0)

------
phs318u
I always liked this aspect of H.P.Lovecraft’s Chthulu mythos i.e. the allusion
to the existence of pre-human civilisations (specifically in ‘Hyperborea’).

------
TMWNN
SCP-1115 [1] is proof!

[1] [http://www.scp-wiki.net/scp-1115](http://www.scp-wiki.net/scp-1115)

------
zaro
Well don't all the megalithic sites which are all over the planet suggest
exactly that?

------
skookumchuck
"Inherit the Stars" by James Hogan is a good scifi story about this.

Also "The Hab Theory" by Allan Eckert.

~~~
fdavison
I really enjoyed the whole Giant series by Hogan.

Star Trek Voyager had an episode with the idea of an ancient saurian species
that left earth many millions of years ago.
[https://en.wikipedia.org/wiki/Distant_Origin](https://en.wikipedia.org/wiki/Distant_Origin)

~~~
pndy
I think TNG's The Chase is yet more interesting; it's also a shame its plot
was never pick up again by series creators.
[https://en.wikipedia.org/wiki/The_Chase_(Star_Trek:_The_Next...](https://en.wikipedia.org/wiki/The_Chase_\(Star_Trek:_The_Next_Generation\))

