Terrestrial or extraterrestrial Silurians? Who got ahead of us?
We have already talked about Silurians on this same channel in the video "Was There An Advanced
Civilization Before Humans? The Silurian Hypothesis." If you haven't already seen it,
run to it now so you have all the information you need to be able to follow this second part!
Earth is the only planet where we know for sure that life exists. And it is also
the only planet in the solar system to have given rise to a technological civilization.
Whether other civilizations then exist beyond the solar system, we can only guess,
but our ignorance on the matter is total. Of course, we know that there are countless planets:
in nearly three decades thousands have been discovered, and starting from the ratio of
the number of extrasolar planets discovered so far to the total number of stars observed,
we can deduce by statistical methods that the potentially habitable planets
in the Milky Way alone are probably more than 10 billion: too many even to count.
But there is one big problem: they are all beyond our reach, and by a lot.
Exploring the depths of space in search of another evolved civilization is therefore an undertaking
currently beyond our capabilities. But what if instead of searching
in space, we search in time? When we search for alien life we tend to
look into the three dimensions of space, looking for planetary environments similar to our own. But
there is perhaps another dimension to look into when searching for aliens, namely, that of TIME...
Our planet is estimated to be 4.6 billion years old and life on Earth has existed for nearly
4 billion years. Is there a possibility that in this boundless expanse of time,
other intelligent species and civilizations have existed and died out before ours?
And this very question is the basis of the so-called Silurian hypothesis,
which refers to an episode of the famous British television series "Doctor Who." That episode,
dating back to 1970, was about the discovery of the Silurians,
an ancient race of technologically advanced reptilian humanoids that allegedly preceded
the advent of humans by hundreds of millions of years. According to the plot, these highly
civilized saurians thrived for centuries until Earth's atmosphere entered a period of
catastrophic change that forced Homo reptilia to hibernate underground to escape danger.
In short, is it possible that some other intelligent species evolved on
Earth in the distant past that created a civilization somewhat analogous to ours?
And from this question immediately arises another: if it ever existed,
what geological traces should we look for to prove its existence?
The starting point is this: the rocks beneath our feet probably constitute
an incomplete encyclopedia of Earth's history.
The earliest footprints of Homo sapiens are still fresh on the Earth. Our species
dates back about 300,000 years and our industrial capabilities to less than 300.
We arrived late on a planet that has orbited the Sun for 4.6 billion years. Enough time, some
speculate, for other earlier civilizations to have developed and then disappeared without a trace.
Over the past 2.5 million years, the geological record shows evidence of climate change,
different soils, and fragments of older hominid cultures, such as Neanderthals and Cro magnons.
But the further we go back in time, the more sparse the physical remains become. All
objects belonging to civilizations more than 4 million years old, the evidence suggests,
are probably lost forever due to continuous soil remodeling and abrasion by the elements.
The built structures we have constructed-highways, railroads, bridges, cities, skyscrapers, dams,
etc. - tower mightily before our eyes today; the very surface of the planet appears extensively
altered by human activity with effects visible from space, as evidenced by satellite photos
of cities illuminated at night by electric lights or those of the millions of km² of land,
covered by the geometric grid of cultivated fields. But the unraveling of all these works
on the scale of geological time will occur in roughly the blink of an eye.
If the human species were to disappear tomorrow, in less than two million years
erosion and sedimentation, acting relentlessly on the currently inhabited territories,
would erase all traces of the cities and artifacts produced by industrial civilization.
Perhaps only the great pyramids of Giza would endure for a fraction of a million years.
It follows that the chances of coming across the remains of an industrial civilization
that existed millions of years before but lasted only a few thousand years are truly
minimal. And it is also highly doubtful that such a civilization ever existed.
Nevertheless, the Silurian hypothesis, which arose more as a provocation than anything else,
is interesting because it makes us reflect on the immensity of past geological time and the
rapidity with which the traces of civilization such as ours would be eroded and eventually
hidden by the uninterrupted remodeling of the earth's surface and ocean floor.
There is, however, one aspect we have not yet considered in the Silurian hypothesis. What if
a remote terrestrial civilization-reptilian or otherwise-had acquired a level of technology
that allowed it to fly into space? Should that be the case, it is more
likely that we could find traces of its very distant past, not on Earth,
but rather on other nearby celestial bodies: the Moon, Mars--all worlds on which tectonic
and erosion phenomena are much less present. Remember the black monolith discovered on the
Moon inside the Tycho crater? That's it-something like that.
Again, that was literature, but let's remember that Arthur Clarke,
the author of 2001: A Space Odyssey, was someone who never missed a prediction…
"Hey, guys, just a moment before we continue... BE sure to join the Insane Curiosity Channel...
Click on the bell, you will help us to make products of ever-higher quality!"
These suggestions aside, unfortunately, the Silurian theory is invalidated not only by
the failure to find clues but especially by the biological impossibility that another
terrestrial species had time to evolve before our own. Indeed, scientists seem to agree that
the first single-celled organisms appeared on Earth about 3.8 billion years ago and that this
must be considered the minimum time to give rise to a technologically advanced
civilization. According to science, therefore, no other civilization of terrestrial origin
could have evolved more rapidly, preceding ours by hundreds of millions of years...
You may have noticed, however, that we specified "of terrestrial origin..."
And if we have done so, there is a very specific reason.
Indeed, the last hope for those who want to continue to believe in the hypothesis
of civilization before ours is to imagine that the hypothetical civilization that settled on
our planet was not of terrestrial origin... but completely alien!
Okay, we know very well that we are flying with the imagination, and that we want to
write a novel where the aliens, having gone out the door, come right back in through
the window... This time not as threatening invaders, but in the guise of colonizers of
a still virgin and uninhabited planet. And after all, why not? We could call
it the extraterrestrial Silurians hypothesis! After all, which do you see as more likely--the
hypothesis of an evolved terrestrial species that preceded our own, or the visit of one of the many
alien civilizations of whose existence, by the way, we have always said we are absolutely sure?
Biologically, the extraterrestrial Silurian hypothesis is surely more likely, don't you agree?
Not least because - let's face it - Earth is a really great planet, which would have appealed to
any vanguard of aliens looking for a new home. In fact, our planet enjoys very special
astronomical conditions: the optimal distance from the Sun, the low eccentricity of its orbit, and
the special characteristics of our star; all this keeps Earth permanently in what astrobiologists
call the "habitability zone" around the Sun. In addition, the Sun is at a good safe distance from
the center of the Galaxy, where most stars crowd in, where large doses of ionizing radiation are
produced that are lethal to the evolution of life. The Moon also makes a surprising contribution to
the habitability of our planet. Thanks to the presence of the Moon, the tilt of the Earth's
axis, to which we owe the changing seasons, has remained almost constant for billions of years,
ensuring the necessary temperature stability that is required for the evolution of life.
If someone had not "invented" the moon, we would not be here today.
We also owe a great deal to other planets in the Solar System: for example, Jupiter and Saturn,
whose intense gravitational field, placed at just the right distance from Earth and the Sun,
act as our guardians against asteroids, which would otherwise,
with severely increased frequency, strike us, devastating the Earth in an unsustainable manner.
But it is not just a matter of location--there is also the particularity of the internal structure,
chemical composition, atmosphere, and especially the geological structure.
The famous plate tectonics, in fact, functions as a thermostat without which
large amounts of water could not remain in a liquid state for billions of years.
And it is also indispensable for the formation of continents and mountain ranges; otherwise,
life would have remained confined to the oceans, at a relatively low level of complexity.
But even assuming that these hypothetical extraterrestrial Silurians were attracted
by such beauty ... one has to wonder, however ... if they really visited us,
when might this have happened? Yes, because for a long time the Earth was not the paradise
we have just described...quite the contrary! Just after formation, our planet was a fiery,
semi-liquid globe, which only after a hundred million years began to cool
enough to form a surface crust. Absolutely nothing attractive!
The first oceans formed after another 200 million years, 4.3 billion years ago. All
thanks to water vapor released into the Earth's atmosphere by massive volcanic phenomena,
which then cooled and fell back in the form of torrential rains over millennia.
A decidedly unwelcoming little environment! That would not improve for at least a billion years,
marked by a frightening and continuous bombardment of asteroids and comets.
It was not until a billion years ago that the Earth began to become quiet, beautiful to look at,
and desirable--at that time it must have appeared from space even bluer than it does today,
with a single large continent in the middle of a pristine ocean. There was still very
little oxygen, but go figure out whether that could be good or bad for the alien Silurians...
Meanwhile, life had begun to peep out, but it was still very little -- almost invisible organisms.
The transiting aliens, if indeed at that time they came upon our planet, must have thought that the
place must have been completely uninhabited... It is also commonly accepted that the first
vegetation to spread on land appeared no earlier than half a billion years ago. A billion years
ago, therefore, the Earth must have appeared bare from one end of the continent to the other.
Here, in our opinion, that 1000 to 800 million years ago must have been (if there ever was)
the best time to take possession of the Earth. And here, then, dozens of spaceships may have
descended on the planet, and their occupants may have begun to establish their first colony.
It is useless to try to guess whether it was a few explorers, or whether many arrived. Nor try
to speculate on how long they stayed, and whether they had time to establish a real civilization...
Why did they leave? Well, as far as is known,
770 million years ago, the Earth went through an ice age so severe that the oceans froze
completely, turning the Earth into a kind of giant snowball. A prohibitive environmental
condition for any living thing, which lasted no less than a hundred thousand years...
It may be that the hypothetical extraterrestrial Silurians slowly died out due to the continuously
worsening climate, or they chose in time to seek escape to more hospitable planets...
Who can tell now? Whether they remained a thousand or a hundred thousand years
does not matter--no trace of their passage could ever have reached us
anyway through the millions of centuries that separate us from those times...
One more mystery among many that will remain so forever.