Imagine if you were a member of an alien civilization.
Looking around you, you might see things that an earthling might find very strange.
Trees with black leaves, a red dwarf sun in the sky, and a planet that exists in one half
perpetual darkness and in another punishing constant light.
You might live in the twilight, the area of this world that sees some mix of light and
dark, but cannot exist in the whole of it.
Imagine a much bigger Antarctica and much bigger deserts.
Imagine you were a very old alien civilization on this world, perhaps a billion years old
since the advent of your technological empire that you once only barely achieved because
of the harsh conditions of your world.
Maybe the only clues you have to your biological origins are vague archeological examinations
of the geologic record, assuming your planet still has one.
All else is lost to the immense time your civilization has existed.
Data can be destroyed, calamities can happen, and those might have left you with less of
an understanding of your origins than we humans have, ourselves being much closer in time
to our own origins.
As anatomically modern humans, it’s only been a few hundred thousand years.
From the beginning of our technological civilization, far less.
But that may change, and in only a few centuries we ourselves may no longer be in our original
biological form but rather something else.
Something new.
Aliens aren’t beholden to their biology either, and with a command of genetics and
advanced computation may have left their biological forms completely and no one member of that
civilization can recall the times of non-synthetic biology.
Imagine that alien world again, even the formerly natural animals and plants of your world have
become technological mirrors if their former selves, uplifted at some point by some previous
iteration of your past society.
Perhaps everything alive on your world is intelligent, made that way out of some cultural
obligation to uplift all species, or perhaps selective intelligence giving only what is
needed to meet your end goal.
A plant that can deploy its own grow lights when needed would be a useful plant indeed.
If you were in this position as a supercivilization, you might know what the great filters truly
are that create the Great Silence that you yourself still see after all these millenia.
Say in all your years you’ve never seen another instance of alien life.
Would you continue to look?
Would you deem it worthwhile to send out messages of your own after having tried that very long
term only to hear nothing in return.
Would you start at some point to simply ignore the universe once you had a full understanding
of it, and turn inward and never notice other civilizations popping up around you.
That is the first part of the problem of time within SETI.
We don’t know what timescales alien civilizations operate on.
Do they last immeasurable amounts of time, hanging on indefinitely until whatever end
the universe meets that prevents them from going on any longer?
Or do they last very short periods of time, snuffed out by their own technology, a risk
we run.
If this is the case, then it may very well be that the reason we don’t see alien civilizations
is that they are all flashes in the pan and the odds of us just happening to exist right
now in a position to see another civilization are just too terrible to ever expect to see
anyone.
You could call this solution to the fermi paradox the ships passing in the night scenario
where a galaxy like the Milky Way may produce hundreds or even thousands, or possibly millions
of civilizations over it’s effective lifetime of trillions of years, but the chances of
any two existing at the same time is exceedingly low.
If the average duration of a technological civilization is, say, 10,000 years then it’s
unlikely anyone is going to see anyone else.
If the average period a civilization remains technological is much shorter, say 300 years,
then it becomes almost impossible.
This would be a sad universe indeed, where almost all alien civilizations look out into
the cold and the dark and see only nature but never a companion civilization.
Perhaps in some distant galaxy there might be contact, a rare and precious thing where
the luck of the odds just happened to be in the favor of a pair of civilizations, but
for most, it’s only silence and the uncertainty that the profound quiet must mean that no
one ever makes it past a coming great filter.
We would then truly live in a universe where all signs of life are necrosignatures of extinct
species.
This problem gets even worse if intelligent life is exceedingly rare in its own right
and almost never happens.
Rare intelligent life coupled with rare technological survival could provide perhaps the simplest
resolution to the Fermi Paradox.
But it might also be paradoxical in its own right, because no two civilizations are likely
to be culturally and developmentally similar.
Perhaps there are worlds out there that by their nature never had conflicts and warfare,
managed their resources wisely and simply do not suffer from our all too human problems.
Maybe it’s possible to last a billion years.
That said there could be worse, very advanced aliens that reach levels of technology that
go very wrong in ways we can only imagine.
A good one would be opening up a wormhole only to have an anti-star accidentally come
through and annihilate your sun in one fell swoop of matter anti-matter reaction.
Not good, but such a thing would be a great filter - that for us, if it’s even possible,
lies thousands of years in our future and is not currently on our list of potential
extinction events.
The unenvisioned extinction event.
Another aspect of the time problem within SETI is that we haven’t the slightest idea
what time scales aliens work on.
This is compounded by the problem that we don’t know what time scales we will work
on in 100 years.
Right now, it’s straightforward, we work on minutes, hours, years and so on.
But imagine if the average human lifespan were ten thousand years.
In that case, a year would indeed be a very small amount of time.
And then there is the issue of cost versus benefit in detecting alien civilizations.
And it has to be said, we may alter our perception of time in the future.
It may simply be that contact of any type is materially expensive.
If you detect someone out there, you’ll need to put significant energy into a signal
to them that they’re likely to pick up.
Say it’s a directed radio signal beamed specifically at their planet, say they were
a mere 20 light years away, it would require significant resources to do it unambiguously.
But you probably wouldn’t choose to do this unless you knew for certain that there was
someone there.
For all you know, shots in the dark are a waste, and that holds true for us.
Rarely do we shoot out signals to other worlds, and then, we don’t usually repeat them.
So maybe efficiency is key to alien first contact.
In a paper by Amri Wandel, link in the description below, he details a solution to the Fermi
Paradox where we simply haven’t existed as a technological civilization long enough
to be noticed.
He proposes the concept of a contact era, where after thousands of years of existence
as a broadcasting civilization we finally get noticed, and someone beams a signal to
us, but not earlier than that.
Part of this idea is that biology may be very, very common in the universe.
It may be that the advent of microbial life is simply the end result of a specific process
in organic chemistry.
That’s backed up by some recent findings in the field of figuring out abiogenesis.
We don’t know the entire process yet, the details elude us, but things like the generation
of RNA have turned out to be way easier than we envisioned.
Indeed, one of the reasons we didn’t see these before is simply because we were looking
for something more complicated than what actually happens.
If that holds true for all of abiogenesis, a nut we very probably will crack within the
next few decades, then microbial life is indeed common in the universe.
In fact, it may be pervaded with it.
If that’s the case, and biospheres are common, then you have to ask the question of whether
the great filter is really just that intelligent life is uncommon.
After all, Earth took 4.6 billion years to reach us, and we’re a fairly recent development.
That may mean that for alien civilizations, planets with biospheres are to be expected,
but the vast majority of them have no intelligent life.
Could it be that simple life, or even life on the level of the dinosaurs is so common
that it’s not really of interest to an ancient alien civilization?
Rather they only focus on an exoplanet when they see it has a techno signature?
If that’s the case, no one beyond a radius of about 100 light years likely knows about
us.
That’s a drop in the bucket for a galaxy 100,000 light-years in diameter.
In short, it may be that no one is close enough to know that we’ve become interesting.
They might watch this world because they detected biosignature gasses, but it’s simply sitting
on some waiting list where some alien astronomer checks in every fifty, 200 hundred or 2000
years and ultimately detects us in their sampling and sends out a repeating contact message
that we can’t miss.
But they don’t yet have a reason to do that, since we’re only just barely at our advent
of detectable technological civilization and we must now wait for our signal, such as it
is, to propagate.
Perhaps we as humans are simply impatient in our expectation to see alien radio signals.
Perhaps as the author suggests, the problem is that we have a very small radiosphere.
Almost no one is close enough to pick us up.
And some day, the galaxy may begin to light up for us with directed radio signals.
And it’s worth noting, they may not beam a radio signal to us at all, rather they might
send a probe that needs to cross space-time at sub-relativistic speeds to get here, adding
even more time to the first contact equation.
And, there’s actually a statistical basis for this.
The closer an alien detection is to you, the less likely it is, at least if you look at
it in a certain way.
If you see an alien civilization in the closest star system to you, say alpha centauri, then
an alien presence throughout the galaxy is implied.
If you see them that close, they must be everywhere.
Well, why?
Do they really need to be everywhere?
There’s a lot of real estate in the galaxy and we’re sort of in a backwater on a number
of counts.
This may not be the ideal place to position a probe, only that it becomes an interesting
place to station a probe once you know a civilization exists here.
Which, almost no one yet knows.
And then there is the ultimate time problem, the distance between the galaxies.
If a galaxy hosts only one active civilization at any given time, you might look to other
galaxies for proof of the existence of alien life.
But the further you get out as far as galaxies go, you get to a point, and this goes for
the vast majority of galaxies, where you see the galaxy so far in the past that there simply
was not enough time from the big bang for life to arise in them and be visible on a
galactic scale from your perspective.
Point is, time is somewhat of an understated problem in SETI.
But not just intergalactically, but within the Milky Way as well.
Even artifact SETI suffers from a time problem.
If Aliens in the past had ever passed though and visited Earth, say they landed and stayed
a few months 100 million years ago, the chances of any evidence surviving on earth is basically
zero.
The planet simply weathers and subducts evidence, and things survive in the geologic record
purely by chance.
Something so specific as a few pieces of alien equipment left behind is highly unlikely on
this world.
Such a thing surviving on the moon however, stands a much better chance.
Who knows what we might find as we explore the solar system, but I think it would be
sad if we found something of alien origin, but then go on to never answer the question
as to if they are still around somewhere out there in the vastness of space and time.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently concerned about aliens
uplifting their plant life to intelligence.
Imagine if we did that, that’s a great filter right there.
Revenge of the carrots, and earth becomes an intelligent carrot world until they make
the mistake of uplifting the onions and it’s nothing but great filters from then on.
Very unsettling 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.