According to the higher estimates, the universe is made up of trillions of galaxies,
which hold trillions more stars and planets between them. Earth is everything to us,
of course, but in reality it’s just one in a wide open expanse of endlessly varied worlds.
From tiny, dwarf planets, shivering in the icy climes on the outer edge of a red dwarf system,
somewhere… to massive gas giants, without a surface to speak of but with bone-crushing
gravity that holds everything together. In amongst all that variety, however, could it
be that humans are the last ones standing? This is Unveiled, and today we’re answering
the extraordinary question; what if humanity is the last civilization in the universe?
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Our regular viewers are by now well-versed on the Fermi Paradox - the realisation that,
for all our efforts toward finding it, and despite all the probability that it should exist,
we still haven’t discovered alien life. One proposed (although widely debated) solution
to the paradox is the Rare Earth Hypothesis… which is the suggestion that the conditions and history
of Earth are actually so incredibly uncommon, and the emergence and survival of life is so
not what we should expect, that that’s enough to explain why it is that we appear to be so alone.
Earth is rare, humans are special, and aliens - while they could still exist somewhere - are
never at all likely to cross our path. Again, it’s one of the more contested theories
out there… with many scientists and astronomers arguing that although we naturally think of Earth
as being a special place, in reality it isn’t. Which is why we’re finding more and more examples
of Earth-like planets in other star systems. But, still, there’s also the question of time as well
as location. And it could be that humans are here not only because Earth is near-perfect for us
environmentally speaking, but also because we’ve managed to make it this far in the first place…
while most (or all) other civilizations have fallen by the cosmic wayside.
One question to consider is how long does a civilization (any civilization)
last? The Great Filter theory famously argues that there must be one stage,
somewhere along the line, that most civilizations don’t get past… and we debated in another recent
video whether humans could have achieved the improbable and passed it already. But, for now,
let’s imagine that we have moved through the Great Filter. If we were the only civilization to have
done that, then straight away we could claim to be the last civilization in the universe,
too. But, if we’ve passed the Filter and we’re not the only ones to have done so, then the race
is on between us and those other hypothetical groups to see who can hang around the longest.
The thing that’s causing all of us problems, however, is a theory to suggest that the period of
intelligence is a small one. The implication being that whenever a civilization becomes advanced,
it could only have a short time left before it becomes something else. Extinct.
From one point of view, we’re talking here about self-destruction. And over just the last
one hundred years or so, we can quite depressingly see how humankind has steadily racked up many
possible ways in which it could bring about its own downfall. Yes, we could consider ourselves
advanced by some measures, but we also have nuclear war, fossil fuels, the AI singularity…
they all regularly come up whenever there’s talk of the apocalypse. But, more broadly, there’s a
general idea known as the Brief Window Hypothesis, which argues that whether we self-destruct or not,
our days are certainly numbered. Let’s return to the Great Filter.
To get to this point, humans have travelled through multiple major stages of development.
From abiogenesis to multicellular life forms, to industrial civilizations… to name just three
of the steps along the path that has brought us here, to this moment, today. And the Brief
Window Hypothesis is most concerned with what’s happening in the present, in the gap between being
an industrial civilization (and as we are now) and becoming a spacefaring one (as we hope to be in
the future). This is, of course, where humans are currently operating. The idea is, though,
that we may never be afforded the time we need to take that next step and expand into space, because
before then we’ll have been killed off - either via self-destruction, or just by some natural,
Armageddon event. Asteroid or A-bomb, it doesn’t really matter to the Brief Window. In whichever
way it unfolds, the worst is sure to happen before we become advanced enough to properly explore
the universe. That’s the theory, anyway. And, if it were true, then being the last
civilization would most likely be really bad news. It would mean that humankind was riding its luck,
and that sooner rather than later it, too, would disappear. Our window, just as it has presumably
done for all other civilizations, will close… and the chances are that it’ll close relatively soon.
But naturally, there is another way of looking at this hypothetical, wherein humans run out
the winners. Because, if something like the Brief Window does exist, but humans have either beaten
it, or are holding it off indefinitely, then we’re exceptions to the norm. And we could again
be (or be on the path toward becoming) the last civilization in the universe.
Importantly, though, this isn’t what most scientific estimates
suggest. When it comes to calculating the number of potential alien civilizations there could be,
the famous Drake Equation is usually at the heart of it. And, although the input numbers fluctuate,
the equation more often than not leads us to a big number. To there being many hundreds,
thousands, or even millions of alien civilizations out there. And yet the Fermi Paradox still rules,
and we still haven’t engaged with (or even detected) one of them.
One other (perhaps crucial) reason for that is the extreme distances at play here. With every passing
year, humankind is growing to understand just how incredibly massive the universe really is.
And, when we consider the increasing number of multiverse theories that are emerging, too,
the scale of existence and reality appears to be becoming too big for even one universe
to contain it. On the one hand, the incredible size and distance should lead us with increasing
confidence to the conclusion that there has to be other life out there. If humankind is but a drop
within an ocean of oceans, then surely there must be other drops hosting life, as well? But, still,
that same understanding of size and distance could also lead us in the opposite direction,
and to the realisation that we will always be alone. That it’s no surprise
we haven’t discovered aliens yet, and that we shouldn’t expect to discover any in the future,
either. The universe is simply too big. Approached from this angle, it could well
be that every civilization (ours included) does have a certain window in which to work. A period
of time to flex its muscles as a technologically advanced, forward-thinking society or group.
And, actually, that window doesn’t even need to be especially brief. Because it never really changes
anything… and because regardless, no matter how long humanity lasts for, it could never last long
enough to find, meet or link with alien life. And then the same would go for those aliens, too.
We can send out signals all we want, then, but it could be that the sheer expanse of space condemns
us to going extinct before we finally receive a reply. Equally, it could be that any alien signal
we pick up in the future, could only ever come from a civilization that had long since died out.
And so, from our position, we may as well be the last civilization in the universe.
Or the first. One of many, or one of few. The vast dimensions of time and space could
well trump everything else… no matter how much we want or hope or aim for first contact to happen.
The Brief Window Hypothesis is for now just one potential route toward solving
the Fermi Paradox and working out why we still haven’t found aliens. It ranks
alongside other ideas like the Rare Earth Hypothesis and the Great Filter Theory,
debated by scientists, astronomers, philosophers, and anyone with even a passing interest in why
we’re here. And, as we so often see, so many of these ideas are ultimately shaped by the huge,
incomparable distances that space forces us to face. And that’s why, even if we were the last
civilization left in the universe, we might never reach the point at which we realise it.
What do you think? Is there anything we missed? Let us know in the comments, check out these other
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