Humans are believed to be the most technologically advanced civilization that’s ever set foot
on Earth, or really anywhere in the Solar System.
But are we the first?
Could there have been an advanced civilization that walked the Earth millions or even billions
of years ago, and then died out long ago, their technology and structures lost to the
eons.
And how could we know?
In the last 100,000 years or so, modern humans like you and me evolved here on Earth from
our ancestors.
We started out in Africa, but then over thousands of years, we migrated to every corner of the
planet.
Our impact on this world is clearly visible.
You can can see it in the air, across the land, the oceans, and even out in space.
Humanity is a technological civilization, and we’re bending this planet to our will.
If an alien was dropped down in the middle of a modern human city, it would be immediately
obvious.
But even in the most remote places on Earth, the right scientific instruments would show
our impact on the water and atmosphere of our planet.
But if humanity suddenly disappeared from Earth, our planet would reclaim it.
Plants and animals would recolonize our spaces.
The Sun, wind and rain would weather down our buildings and monuments.
The natural cycles of the planet would clear out the evidence that we were ever here.
Eventually, plate tectonics itself would drag evidence of human existence down into the
mantle, destroying it forever.
Fast forward a few hundred million or billion years into the future and it would be almost
impossible to know humans were ever here.
Which makes us wonder, could we know if we’re actually the first advanced civilization to
live here on Earth?
If another civilization came before us, how could we find them?
This is a question that Dr. Jason Wright, an exoplanet researcher and associate professor
at PennState University posed in his 2017 paper titled: Prior Indigenous Technological
Species.
The paper is all about where we might find evidence for previous advanced civilizations
here in the Solar System, and what might have happened to them.
Before I get started, let me be clear.
Don’t get your hopes up.
There isn’t a single piece of evidence anywhere, at all, that there was ever another civilization.
But we’ve only scratched the surface of exploring our Solar System.
In fact, we’ve barely even explored our own planet.
And conditions could have been different in the past.
The probes and rovers exploring other worlds in the Solar System have told us that the
conditions we see today is just a phase the planets are going through.
Billions of years ago, the Sun was cooler, Venus was probably less terrible, Mars was
warmer and wetter, and more places in the Solar System could have been habitable.
Perhaps an ancient civilization could have survived on one of those worlds, or even the
early Earth, and then became a spacefaring species, spreading to other worlds in the
Solar System.
In order to search for those ancient civilizations, consider what kinds of impact humans are leaving
on the Earth.
That’ll be the first place to search, since it’s easiest to get to.
But Earth is active and the surface is under constant weathering.
Open pit mines, where intelligent species dug out valuable minerals would have filled
in, or been weathered away.
Radioactive isotopes from ancient nuclear reactors might be visible for hundreds of
thousands or millions of years, but eventually they’d decay.
And over the longest timescales, the Earth’s shifting plate tectonics would obscure almost
any sign.
But the Earth also keeps a history of its atmosphere and water in the geologic record.
The pollution from an advanced civilization could be stored in those layers of sediment
over vast periods of time.
According to Gavin Schmidt and Adam Frank in their new paper called “The Silurian
Hypothesis”, which yes, is named after the lizard-like Silurians from Doctor Who, there
could be signals in the geologic record.
They explain how little we actually know about the ancient Earth.
The oldest part of the Earth’s surface is the Negev Desert in southern Israel, which
is only 1.8 million years old.
There are older surfaces from mining or exposure and uplift, but you have to go looking for
it.
There’s no part of the ocean floor older than 170 million years old.
Since only a fraction of living creatures that have ever existed would show up in the
fossil record, Schmidt and Frank say that any civilizations that didn’t last longer
than about 4 million years wouldn’t show up in the fossil record for more than a blip.
You’d mostly likely miss it.
But what about the chemicals humans have been putting into the air?
Humans have released 500 billion tons of carbon into the atmosphere over the last couple of
centuries, and that’s adding a layer to the geologic record that could be detectable
for millions or even billions of years into the future.
And not just carbon, we’re also emitting trace elements like lead, chromium and even
gold, which will be more concentrated than what you’d randomly detect if it all formed
naturally on Earth.
Humans have even changed the fossil record itself, increasing the number of species that
hang out with us, like mice and rats, and killing off the mega fauna.
That might be detectable as well.
In other words, if future civilizations looked carefully, there would be evidence of humanity’s
presence, long after all the other evidence had weathered away.
Perhaps if we look carefully, we’ll eventually find evidence of an ancient civilization that
was destroyed eons ago.
But what if they knew they wouldn’t be around forever and wanted to leave some kind of record
of their existence?
We’ll get to that in a second, but first I’d like to thank:
Mark Steven Michael Halada
Tim Rumph (Rump) Tanglebones
Clint Branham Meris Williams
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Let’s say that an ancient civilization knew that they weren’t long for this Solar System,
and wanted to leave some kind of evidence for us to find, to know that they were here
long ago.
What should we be looking for?
What if a civilization wanted to be remembered?
Jason Wright says that other places in the Solar System would be better preserved.
There’s no wind or water erosion on the Moon, just the radiation from the Sun and
the constant stream of micrometeorite impacts that churn up the surface.
Mars has more weathering, but still, there are features largely unchanged over vast periods
of time.
An ancient factory could get covered in dust or worn down by erosion and look like a rocky
outcrop.
The best evidence is probably underground, safely protected from the ongoing surface
erosion.
But we’d need orbiters or rovers with ground penetrating radar to peer beneath the surface.
For example, NASA’s Europa Clipper is going to be equipped with an ice-penetrating radar
instrument that should be able to peer kilometers beneath the thick ice on the Jovian moon.
There could even been free floating objects in the Solar System like ancient space stations.
They’d have been abandoned long ago, and they probably wouldn’t work any more.
The micrometeorites and solar radiation would be working hard to wear them down.
But we see comets and asteroids which are relics from the early Solar System, largely
untouched over billions of years.
The Golden Records on board the Voyager spacecraft were designed to last at least a billion years,
long enough for the spacecraft to cross almost the entire Milky Way at their current speed.
What if an advanced civilization purposefully gathered their knowledge and evidence of their
existence and put it out into space where we could find it.
Although this sounds like a pretty crazy idea, in fact, humans are working on something like
this right now.
There’s a group called the Arch Mission Foundation, and they want to archive the knowledge
of humanity and store it on the Moon.
If all goes well, a rocket launched to the Moon in 2020 will be carrying an Astrobiotic
Peregrene lunar lander.
It’ll be carrying the entire contents of Wikipedia, as well as a compilation of human
languages, and other content embedded into a microfiche that you could read if you had
a 1,000x magnification microscope.
Once the lander settles down on the Moon, it’ll be safe and sound for billions of
years, for any future civilizations to learn about our history.
I know, I know, you’re wondering what would happen if it gets hit by a stray meteor.
That’s why the Arch Mission Foundation would like to build more and spread them across
the Solar System, to preserve the legacy of humany for our future robotic overlords to
enjoy.
If they’re there, why haven’t we found them?
In their 2012 paper titled “On the likelihood of non-terrestrial artifacts in the Solar
System”, Jacob Haqq-Misra and Ravi Kumar Kopparapu calculate how difficult it would
be to find artificial objects in the Solar System.
Space is big, and it’s hard to find things unless you know exactly where to look.
If there was a 1-10 meter space probe out there in the Solar System containing the total
knowledge of an advanced ancient civilization, there’s almost no chance we’d find it
with the state of our current exploration.
Maybe something on the Moon or Mars would turn up, but imagine if they put it in a nice
stable Lagrange point or out at the Kuiper Belt to minimize the damage from solar radiation
and asteroid impacts.
Clearly, we need to explore more of the Solar System.
You know what would look better than a lander, though?
A monolith.
Imagine if we put these across all the worlds in the Solar System, with instructions about
which worlds are yours, except Europa.
Just saying.
Are we the first advanced civilization here in the Solar System?
Probably.
We haven’t found any others.
But there are places we can look and techniques we can use to find anyone who was here before
us.
So what do you think?
Are we the first advanced civilization in the Solar System?
What kind of monuments would you build to let future civilizations know we were here?
Let me know your thoughts in the comments.
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