A huge question about the Fermi Paradox is that can the “are we alone” question be
answered without ever discovering evidence of intelligent alien life?
After all, our searches so far have turned up nothing conclusive and as far as we can
tell we see only the great Silence.
So can we answer the are we alone question without SETI ever detecting anything?
The answer is yes, sort of, conditionally.
Actual observation of alien civilizations in general is rather limited.
You can search the galaxy, certainly, and to a degree the nearby local group of galaxies.
But the further you go out, the harder it is to detect anything.
Signals get too weak, observations of exoplanets not typically possible at great distances
and so on.
You’d need alien astroengineering on a galactic scale to see it, typically a Kardashev type
III civilization encasing huge amounts of stars in a galaxy inside dyson’s spheres,
or reddening galaxies unnaturally by kicking out or altering dangerous stars to avoid the
supernova problem.
But, so far, we’ve seen nothing of this.
Beyond that, you’re simply looking at galaxies too far back in time from a period when they
didn’t yet have enough heavy elements to form planets and time for life to arise.
This is the brick wall of time.
So unless an alien civilization does something on an enormous, and perhaps impractical scale,
and does it closely we are generally limited mostly to searching in our own galaxy.
That’s not necessarily a bad thing, this galaxy has on the order of 200 billion stars,
most of them ostensibly habitable, so we have plenty of real estate to search.
But to date, no one’s seen anything truly compelling that would indicate an alien presence
in this galaxy.
It’s worth pointing out here however that we’ve only just barely looked.
There are several aspects of this, have we searched every star in the galaxy for radio
signals?
No, nothing close.
Have we searched for other bio and technosignatures?
No, we’ve only barely just started, if that.
And then one really important question, have we looked long enough to see anything?
Not by a long shot.
Alien civilizations may work on much longer time scales than we do, or are so transient
we just miss them.
As a result, we don’t really even know if there is a great silence, much less the reason
for it.
There are some future ways to address these problems such as all sky SETI monitoring coming
in the future, but instead of a great silence, we may still be suffering from a great deafness.
That said, there will come a time where the great silence could assert itself very strongly.
If we spend the next few centuries doing SETI searches and we never find anything, then
it will become less likely at some point that we ever will.
There could come a point in the future where the silence will become deafening.
And that will lead us to a question.
Are there other ways we can explore regarding alien life to try to come to a reasonable
assumption that life in the universe, and civilizations are common or rare?
The answer is yes, and there are three ways and all three potentially could reasonably
solve the Fermi Paradox without ever directly detecting intelligent alien civilizations.
Yes, and any of the three could happen in the next human lifetime, but not definitively.
To definitively answer the question, you need the detection of an alien civilization directly.
The first way is solving the question of how abiogenesis worked on earth.
If you can figure out the mechanism, you can determine if the process is difficult to nearly
impossible, or if it’s straightforward and easy.
Recent evidence interestingly is moving it towards the easier than we thought side of
things, specifically in the areas of RNA genesis and symbiosis being a possible factor in the
leap from simple to complex life.
Should the process prove easy and repeatable, we can look at the conditions required and
if they seem common, then we can reasonably assume that the universe teems with microbial
life at the very least, and that civilizations occasionally arising from that are probable
since we self-prove the concept, we’re here and we prove that nature can produce intelligence
and civilizations, and we’re likely just one member of a population of like occurrences.
The second way is to discover independent life somewhere else in the solar system, whether
that be subterranean Mars, Europa, Enceladus, the upper cloud decks of Venus, and so on.
If you found microbial life, or even macrofauna in an ice shell moon ocean, that’s genetically
distinct from earth, then you have the same effect.
If life arose twice in the same star system, then it very likely is everywhere throughout
the universe.
Again, this does not speak to civilizations, it just makes them more probable to occur.
They might be rare, but nature hates a one off.
There are almost always other examples of something occurring in the universe.
That goes for intelligence too.
The path to investigating the first two ways is clear.
Research, study, sample and find out.
Go see if Mars has life.
Go into the lab and crack abiogenesis.
Those are possible, and indeed scientists are hard at work on both fronts.
But there is another, and while it’s more of a long shot as far as proving it, there
may be a way, and there is already an indicator that it may be the case.
It’s the infinite universe.
And, if it turns out to be the case, then it becomes impossible for us to be alone,
and there must necessarily be countless civilizations out there.
The only problem is that they are probably so distant, we’ll never know about them.
We could only just strongly assume that they exist.
The basis of this is that we don’t actually know how large the universe actually is, we
can only see our own observable universe, which is basically a bubble of the larger
whole.
Some theories suggest that only a small amount of the universe lies beyond the observable
border, but others suggest that it could be very large.
And it’s possible that it’s infinitely so.
Infinity by its very nature opens up a certain reality that anything that can happen will
tend to happen and that goes for civilizations.
Since intelligence is possible, and we represent it, it becomes impossible for there not to
be other occurrences of civilizations.
They would be infinite in number.
But this also necessarily means that some of those civilizations will be almost identical
to our own, to the point of being doppelgangers.
But there would also be truly alien civilizations that too have doppelgangers of their own and
so on.
It would be a universe where if you traveled far enough, you’d come across an almost
identical twin to Earth, and you’d no doubt encounter many civilizations in between that
are nothing like us.
In other words, an Infinite universe dissolves the Fermi Paradox and dictates that there
must be others out there.
You may never see them or interact with them, but it’s a certainty that they will be there.
So do we have any indicators that the universe is infinite?
Actually, we might, and as our understanding of cosmology continues to improve we may someday
be able to determine it definitively.
No one yet knows, but one aspect of this is the overall geometry of the universe.
We know that the big bang happened 13.8 billion years ago, and due to the expansion of the
universe, our bubble has a radius of about 46.1 billion light years.
That’s huge.
But there are indications that the universe overall may be a great deal larger, or even
infinite.
So this brings in the overall geometry of the universe.
If as a whole, it were positively or negatively curved, two beams of light, or say a pair
of railroad tracks extending a huge length of the total universe, they would either converge
and meet, or diverge at some very distant point.
This doesn’t seem to be the case, two parallel beams of light will never curve and meet or
diverge, they just keep on going as you’d expect them to.
That means our universe appears to be spatially flat on its largest scales.
That allows for some limits to be set on the lower end of the size of the actual universe.
And this is where it gets crazy, it needs to be on the order of 37 trillion light years
in diameter.
That means the observable universe is only a very, very tiny bubble indeed, and if the
universe continues on much like the part we can see, which it very likely does, this dramatically
increases the chances for intelligent life somewhere in the universe.
We just can’t ever see it if it’s out there.
But at that point, it’s almost certainly there or there’s something very strange
indeed going on with this universe.
But that’s not infinite necessarily, the point at which we can consider alien life
a certainty.
But there are some clues here that even at those scales, we may still be underestimating
the size of the universe.
And this is where the mysteries start: we don’t really know certain key conditions
and features of the big bang to estimate just how large the universe is, and indeed if it's
infinite.
This requires a better understanding of cosmic inflation, and while that’s not entirely
clear now, there may come a time when we understand it.
Or we may never have enough of a bubble of the universe to understand it completely.
We just don’t know.
The point is though, the larger the universe, the more chances you have for the development
of alien intelligent life.
The odds grow and grow until they simply become overwhelming.
This is why a lot of scientists, though there are dissenters, suspect that alien life, even
intelligent life, must be out there somewhere.
The numbers are just too stacked against it not being there, and get increasingly worse
if the universe is so much more enormous than what we can currently see.
With an infinite universe, it becomes a certainty and the Fermi Paradox reduces down to a single
solution.
Aliens exist, but in the future after spending centuries looking for them and we still see
nothing, then the solution reduces to all alien civilizations are simply too far away
to detect or interact with.
And while that might seem disappointing, it pays to remember that there are strange things
about this universe we do not understand, and such things as spooky action at a distance,
that do exist hinting perhaps at unknown physics that we may someday unlock allowing for things
we can’t currently envision.
And that too is a solution to the Fermi Paradox, that we simply didn’t have a complete enough
understanding of Physics to even notice the aliens.
Thanks for listening!
I am science fiction author and futurist John Michael Godier currently addressing the sleep
crowd.
One of the most common questions I get in the comments is regarding the content I fall
asleep to.
This varies, and used to involve AM radio, but youtube content not so much as I get too
interested in the subject matter.
Rather I watch youtube channels fully awake and engaged.
But to fall asleep, well I’m about to turn 47 so TV that was in rerun in the early 1980’s
when I was a little kid does it for me.
I can’t last ten minutes after hearing the theme songs from Taxi, MASH or even the much
later Cheers without happily drifting off and there’s always reading in bed which
does it too and be sure to check out my books at your favorite online book retailer and
subscribe to my channels for regular, in-depth explorations into the interesting, weird and
unknown aspects of this amazing universe in which we live.