November 7, 2018 • 36 mins
Ever wondered where all the aliens are? It’s actually very weird that, as big and old as the universe is, we seem to be the only intelligent life. In this episode, Josh examines the Fermi paradox, and what it says about humanity’s place in the universe. (Original score by Point Lobo.)
Interviewees: Anders Sandberg, Oxford University philosopher and co-creator of the Aestivation hypothesis; Seth Shostak, director of SETI; Toby Ord, Oxford University philosopher.
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
This is a love letter to humanity. My name is
Josh Clark, and for the last few years I've been
thinking a lot about how the world might end, and
over the course of that time, I've come to seriously
believe that in a hundred or two years from now,
there's a really good chance that we humans won't be
(00:21):
around any longer, that we will have vanished forever from
the universe, and that it may be us who brings
about our own demise. This series is about the very
real ways that that could happen. It's meant to open
your eyes, hopefully get you to take these ideas seriously too,
(00:44):
and ideally get you to take action. But just as much,
I hope by pointing out just how close we are
to the brink of disaster, you come to feel the
way that I have about your fellow humans and humanity
as a whole. That we are flawed and ugly and brutal,
(01:04):
for sure, but that we are worth fighting to save,
even from ourselves. That the beauty and the love that
humans are capable of creating is greater than the worst
of our faults. That nothing we've done is worth letting
our entire species come to an untimely, impermanent end. It's
(01:25):
a bizarre thing to say, but I found it's worth saying.
Humans don't deserve to go extinct. This series is about
existential risks. We're not used to this kind of risk,
nor are we really equipped to deal with them. I'll
tell you a lot more about them as the series
(01:46):
goes on, but while you listen, try to keep in
mind that no horrible catastrophe, no world war, no epidemic
that's ever come before, nothing we've ever been through has
prepared us to take on existential risks. We have no
frame of reference for them, because the destruction they can
(02:06):
bring is unprecedented in the history of humanity. Yet, and
what maybe the weirdest turn of events in the history
of our species, A whole crop of these new existential
threats are suddenly looming in our near future. Each one
of them could bring about the sudden and permanent end
(02:27):
of the human race. This would be a particularly tragic thing.
We humans have only just begun to live. Human civilization
has been around for about ten thousand years. Think about
what we've accomplished in that relatively short time. Now, think
about what it might be like to be a human
after civilization has been around for a million years or
(02:50):
a billion. So not only are the lives of those
of us around today on the line, but we have
to remember the lives of all the humans to come
are as well, and the stakes for us avoiding extinction
in the next century might be even higher than that.
As we'll see in this episode, we humans may be
the only intelligent life in the entire universe. If we die,
(03:15):
so too does all the things that make us human,
All of the love and compassion, all of the inventiveness
and curiosity, all of it perishes with us, not just
here on Earth, but in the universe as a whole.
It's staggering to think, but the responsibility for our own lives,
for the future of the human race, and for intelligent
(03:37):
life in the universe appears to suddenly rest solely in
the hands of those of us alive today. It would
probably be good to know if we're alone or not,
just for the sake of knowing what's on the line
if we go extinct, So let's start there. As it
turns out, you should know an alien by now, so
(03:58):
should I. By this point in human history, everyone you
and I know should know an alien. We should know
them from work, from your kids school. They should be
our neighbors. Earth should be a melting pot of not
just human cultures, but extraterrestrial ones too. At the very least,
we should be certain by now that there are aliens
(04:20):
out there, just as sure as we know that there
are people living in France and Denmark. We should know
that there are aliens on proximous Centauri B or trappist
One F. And yet we don't, and you and I
don't know any aliens, which is actually very, very weird.
The reason why it's weird is that the universe we
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live in is extremely old. It's nearly thirteen and a
half billion years old, and our galaxy, the Milky Way,
is extremely vast from the perspective of us humans. It
takes a beam of light a hundred thousand years to
cross it. And within our very old and very immense galaxy,
there are a lot of stars, between two hundred to
(05:03):
three hundred billion of them three hundred thousand million stars.
Working from the premise that our own stars, light and
heat helped raise life here on Earth, one would think
that somewhere among those three hundred thousand million stars out there,
the same thing would have happened. It happened again and again.
(05:25):
By all rights, even with just a slight fraction of
those stars growing life on a planet in orbit around it,
our galaxy should be teeming with life like mold on
a slice of bread. There's certainly been plenty of time
for it to happen. Here on Earth, life arose within
the last three and a half billion years and managed
to evolve from little strands of proteins into us, sentient
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human beings who have come to wonder if the same
thing has happened elsewhere too. Since the galaxy is nearly
four times older than the time it took for intelligent
life to emerge here on Earth, it's had ample time
to emerge elsewhere in our galaxy too. So what we've
got is something of a mystery on our hands. The
universe is by far old enough and definitely large enough
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to have produced intelligent life over and over and over again,
and yet we have not one iota of evidence that
we are anything but utterly alone in the Milky Way.
It's become increasingly clear that when we look out at
the night sky, there's nothing looking back at us. This
(06:31):
is the basis of what's come to be called the
Fermi paradox, and it begins, like so many great strange things.
Over lunch in the summer of nineteen fifty four physicists
ambled over to the Fuller Lodge, an old two story
boarding house made of human logs with a big, hulking
(06:54):
stackstone fireplace that you could practically stand up in. The
Fuller Lodge had been converted into a mess all for
the people working on the Manhattan Project at Los Alamos,
New Mexico. Taking a break from refining the most destructive
weapon the world has ever known into an even more
destructive one, these four physicists got into chatting about the
(07:14):
UFO fever that had recently gripped America. They dismissed the
idea that reports of UFOs were in fact alien in origin,
but they didn't dismiss the idea that it was possible
life could exist elsewhere in the universe. It was likely
that it did, they concluded. After the group had already
moved on to other topics, one of them, Enrico Fermi,
(07:35):
abruptly returned the conversation back to aliens. Where is everybody?
He asked, or perhaps, but have you ever wondered where
everybody is. The precise words were lost over time, but
Fermie's three lunch companions all recalled that they knew just
what he meant, and they grasped the implications as well.
There should be life all over our galaxy, and yet
(07:57):
there appears to be only us. Fairmi never formally explored
his question, but it's understandable why it came to be
named after him. As physicists go, Faremi was no slouch.
He presided over the first controlled nuclear reaction created in
a uranium pile of his design, constructed on a squash
court beneath the football field at the University of Chicago.
(08:19):
He calculated formula that helped answer the shape of matter
on the quantum level, and a family of quantum particles
are named after him Fairmians, and of course he helped
build the bomb. But more than Fairmi, it was an
American astronomer named Michael Hart who was really responsible for
the Fermi paradox. In the mid seventies, Heart wrote a
(08:40):
paper called the Explanation for the Absence of Extraterrestrials on Earth.
He summarized and organized the arguments against the paradox, which
come in a rainbow of colors with only a couple
of shapes, and Heart ultimately concluded this because life should
reasonably have emerged and be known to us by now.
The fact that it hasn't solves the family paradox. The
(09:03):
answer is that we are alone. Mystery solved. Michael Heart's
paper struck a blow in particular to the group most
diametrically opposed to his conclusions. City researchers set the search
for extraterrestrial intelligence is an offshoot of astronomy and astrobiology,
(09:23):
and back in the early sixties, astrobiology hit the scientific
scene like a bomb. It was an exciting new discipline
that treated the possibility of extraterrestrial life is real. In
sharp contrast to the people who agreed with Heart, the
astrobiologist camp was populated by optimists who reasoned that it
is simply too unlikely for life to evolved only once
(09:44):
throughout the entire universe. We just needed to hone the
way we search for aliens, and we would surely find them.
Cd He evolved is the intelligence gathering arm of astrobiology,
and set about listening for alien transmissions by aiming radio
telescopes at the center of galaxies that seemed likely to
host life. By the time Michael Hart published his paper
(10:06):
said he hadn't found anything, and Hart included in his
article that said he was an utter waste of time
and resources. By that time, many others, including some in
Congress who funded things like st tended to agree that
there is little justification for twelve million dollars taxpayer dollars
to be expended for this program. Madam President, I urge
(10:28):
my colleagues to vote in favor of this amendment, and
I reserve the balance of my time and yield the floor,
and I thank the chair. Yet neither hearts paper nor
sti's empty handed searches have settled the mystery of the
family paradox. Because we've gotten better at observing our universe,
this little mystery has only gotten more weird. Thanks to
(10:50):
space based telescopes like the Kepler and new methods we've
developed for watching stars, we found that there are a
mind boggling number of potential earthlike planetile there. To qualify
as a potential host for life, the planet has to
check some boxes. The star that it orbits has to
be of a certain type, and in what's called its
main sequence, it helps to be around the size of
(11:12):
our Sun, which is right in the middle. Size Wise,
big stars go through their fuel too quickly to give
life a reasonable amount of time to emerge. On the
other end, smaller stars don't burn quite warmly enough. The
planet has to be a particular distance from the star.
Too too close and any life would be burned to
a crisp Too far away, and the star's warmth couldn't
(11:34):
overcome the unbearable cold of outer space. Either way, the
conditions wouldn't allow for water to form or an atmosphere,
both of which we assume are requirements for life to emerge.
The planet needs to be in a spot relative to
the Sun that's not too hot and not too cold,
but just right for life. So it may not come
as much of a surprise that some astronomers call this
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area the Goldilocks zone. Taking all of this in to account,
there are perhaps tens of billions of potentially habitable planets
in the Milky Way alone, and it gets even weirder.
Throughout the decades that people have attempted to resolve the
family paradox, those attempts have always been focused on our galaxy, specifically,
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the rest of the universe is just too big to
allow for the time it would take for another civilization
to travel to the Milky Way and make its presence
known to us. So by leaving out the other hundred
billion galaxies in the universe and there's seventy billion trillion stars,
the idea that perhaps other life might exist outside our
own galaxy was allowed to stay aglow as a faint
(12:39):
member of possibility, But in two thousand thirteen that ember
was snuffed too. A pair of philosophers from Oxford figured
out that the math shows there has been plenty of
time for intergalactic civilizations to have evolved and traveled to
our galaxy too. This is one of those Oxford philosophers
under Samberg, actually suppose you wanted to go out and
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colonized as far as you could, how far could you go?
And we found that you can literally do this over
billions of light years, which means that this is also
something aliens could have done. So if it's a bit
weird that we haven't noticed in the alien spreading across
the Milky Way, now we need to take into account.
(13:22):
But actually there are also millions or billions of galaxies
where aliens could have come from but they haven't shown
up yet. So when we finished that paper, we kind
of pointed out that we made the Fermi paradox a
million or a billion times worse. The Family paradox extends
not only to our galaxy, but it seems to the
entire visible universe. Hm to a lot of people who
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think about this kind thing, it's simply too outlandish to
believe that we are the only intelligent life in the
entire universe, and so over the years, people have put
forth some interesting answers to the family paradox on the
basis that there is intelligent life out there, we just
don't know it yet. At the most basic level, the
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arguments consists of the notions that aliens either can't or
won't make the trip to see us. Aliens have had
plenty of time to colonize the galaxy and even the universe,
as we've seen, even considering travel at less than the
speed of light, even travel at ten percent the speed
of light shall allow for the Milky Way to be
colonized in fifty million years at the most. But even
(14:41):
allowing for plenty of time to make the trip, it's
entirely possible that the trips between stars and galaxies is
extremely difficult, so difficult in fact, that no intelligent civilization
has ever successfully managed it, although plenty may have tried
and lost a lot of their people to be impossibly
hazardous trips before finally giving up. Space is far from empty.
(15:04):
It's full of tiny particles called cosmic dust, raw material
that planets are made from. There's a dust cycle out
in space where dust is blasted into space by exploding stars.
This dust fills space, and even though it consists of
extremely tiny particles, it would pose a hazard to any
spacecraft traveling at some significant fraction of the speed of light,
(15:25):
which again, remember something like six hundred and fifty million
miles an hour. Even a tenth of that is still
sixty five million miles per hour. At these speeds, the
spacecraft kinetic energy is so unimaginably huge that a collision
with even some tiny piece of matter would be catastrophic.
MT physicists calculated that impacting even a single grain of
(15:47):
cosmic dust would be tantamount to the explosion of something
like two and a half tons tons of T and
T aboard the ship, and cosmic dust is just one
hazard that space bearing species would have to overcome. There
are surely plenty of others that we haven't learned of yet.
This argument has a flaw to it, though, and I
(16:07):
want you to pay attention to it, because it's part
of a theme that really all arguments regarding the Family
paradox share. If the reason aliens haven't colonized the universe
is because it's extremely hard to travel between stars and galaxies,
that means that it is so hard that not one
single intelligent civilization managed to figure out a way around it,
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not one out of the potentially millions or billions or
even trillions that may have evolved over the life of
the universe. This is important because to resolve the Family paradox,
it would take just one of them to have learned
how to survive the trip, to colonize the galaxy and
show us that we are not alone. And you can
argue that it would really only take one, one single
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member of one single civilization of the potentially trillions of
them to make it to Earth and make their presence
known to us to have proof that we are the
only intelligent life in the universe, which makes the Fermi
paradox even stranger or more clearly settled, depending on your view.
The other side of that particular coin holds that other
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civilizations could colonize the galaxy or even the universe, they
just don't want to. There are a lot of theories
as to why that might be. Now it's possible we're
anthropomorphizing aliens here. We humans will almost certainly colonize the
galaxy if we ever get the chance to. So, perhaps
we're relying too heavily on the assumption that any life would.
(17:34):
This is the senior astronomer at the Study Institute set
show Stack. All of this, all of this is based
on trying to guess, because that's really the correct verb,
to guess what is important to the extraterrestrials. And I
don't think that we're actually very good at that any
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anymore than you know, the ancient Greeks would have been
very good at guessing it's important to century Americans. I
don't think that they could have seen foreseen the kinds
of things that would be important to us. Perhaps the
civilization develops to the point where it's technologically capable of
interstellar and intergalactic travel, it loses its taste for such things.
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Perhaps the civilization goes philosophical and contemplative a race of
beings who prefer to spend their time thinking about the
meaning of life. You're solving the deepest mysteries of the
universe from home. But even the most inward focused society
would have good reason for expanding from their home planet.
As their population grew, they would need more and more
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raw materials to keep them alive while they sat around
in contemplated life. It would be more space, more energy.
The need for scarce resources appears to be one of
the few universal commonalities that any civilization will have to
deal with. This is good. This means that we can
pretty confidently use this clue to predict the behavior of
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any intelligen life. Then we humans run into limitations on
our ability to grow or make food, so we need
more space for that. We need space for our bodies
as well, since each person needs somewhere around one point
six one point seven meters of physical space to stand
up and extend our arms with him, plus we tend
to like a little extra to move around into. Requirements
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like these mean we would eventually face the prospect of
either systematically curtailing our population growth to maintain no more
than what the Earth can support and based on all
current and historical data, we tend to overstrain the planet
rather than work within its confines, or we can spread out.
It's difficult to imagine that any advanced society faced with
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resource pressures would not look out to at least their
own solar system as a source of material solutions to
their problems. This scenario extends further and further, both into
space and time. As the society continued to grow, they
would take up more and more space, and over long
enough spans of time, they should reasonably have colonized a
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sizeable chunk of their galaxy, if not the whole thing,
even with their desire to remain inward over so many generations.
But maybe aliens have good reason to resist the urge
to spread out. Maybe they're hiding from something, Maybe they
know something that we don't know. One of the long
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standing theories about why a civilization with the capability of
traveling to other stars would opt not to is the
idea that they might be afraid of something. Perhaps there's
some older civilization that doesn't like to compete for scarce
resources with young upstarts like ourselves, the first civilization to
have colonized the galaxy would have all the advantage over
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any others that came later, even considering a hundred thousand
year head start, which though it's tough to remember that
the cosmic time scales we're dealing with here is the
blink of an eye, and earlier civilization would have time
to see the galaxy with things like berserker probes, hypothetical
type of self replicating space probe designed to attack and
(21:26):
destroy entire civilizations. These berserker probes would be capable of
strangling in the cradle the colonial aspirations of any younger
civilizations before they ever got started. Right about where we
humans are in our progress right now. What's ironic about
berserker probes is that they can produce their own solution
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to the family paradox without even existing. We humans thought
of the possibility that they could exist, so it stands
to reason that other intelligent civilizations might too. It's possible
that part of the process of the umbing and intelligent
society engaged with the unknowns of the universe is to
start having second thoughts about signaling into the void and
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instead to go silent. Eventually, every single one of these
societies might stop attempting to communicate and resigned to just
sitting and listening instead. So the universe could be teeming
with intelligent civilizations, each being quiet as a dormouse, each
listening and unaware of the existence of the others, and
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the berserker probes wouldn't even have to exist beyond the
hypothetical for this solution to the family paradox to work.
But if berserker probes do exist, why wouldn't we have
had an unpleasant visit from them by now? Transmissions from
our radio and TV shows have been traveling through space
since we first started broadcasting here on Earth in the
early twentieth century, and steady researchers have been actively shouting
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at other star systems with radio since the sixties. Probably
the most unsettling answer is that we did get their attention,
and they're on their way. They just haven't had time
to reach us yet, or perhaps they don't much care
about us so long as we stay here on Earth
or even within our own galaxy. In two thousand and seventeen,
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Oxford philosophers Stuart Armstrong, Ander Samburg, and Milan Turkovich developed
a new explanation for the Fami paradox that says that
perhaps the universe does contain berserker probes, but rather than
actively patrolling the galaxy, they are posted on the outskirts
of some ancient civilizations state territory while the civilization sleeps.
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This new idea, called the estivation hypothesis, supposes that the
civilization in question has reached a post biological state. Post
biological civilizations are their own can of worms entirely, and
we'll talk about them more later on. But what they
amount to is a species that has shed its biological form,
whether it's an upright bipedal form like us humans, a
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giant root, vegetable, whatever, and has preserved its minds into
a computerized form. There are myriad advantages to this. Less
physical space is needed, you don't need to grow food.
But these civilizations are not free from scarcity either. Here's
philosopher Ander Samberg again. So suppose you're a really advanced civilization.
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You've been around for millions of years, you kind of
explored in the galaxies, You've done most of a big
physical stuff. At this point, probably most of what you
want to do is going to be kind of cultural.
We have no idea as umus what an advancedivils might
want to do. But I think it's a pretty certain
bet that it's going to require competitions of some kind.
(24:40):
Information processing a k. A. Computing has its own requirements.
It needs energy and it produces waste heat, two huge
factors that a post biological society would come up against
as it uploaded more and more of its population to
a digitized format. Rather than food, water, and couple of
square meters of physical space, they would need processing power
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and speed to keep their digitized minds humming along and
to simulate the world for them. So a post biological
society would have very good reason to colonize their galaxy
in search of more raw materials to build hardware and
to harness more energy from They will probably build massive
engineering projects to capture energy from entire stars, like through
(25:27):
some variation of Dicen spheres to a hypothetical energy collection
machine that could be constructed around a star to capture
some enormous fraction of its energy. They may deconstruct entire
planets to build those Dicen spheres, so they may have
energy and aces. But at some point a post biological
society might strike upon a seemingly insurmountable truth about information processing.
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Regardless of how efficient it is, computing produces some amount
of waste heat. This can be tricky enough with a
single server him here on Earth in the early twenty
one century, those racks of servers have to be cooled
with fans, and the room has to be air conditioned.
So that means that not only is the actual process
of computing taking up energy, there's an additional energy expenditure
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required to keep the hardware cool. Heat is the sworn
enemy of efficient information processing, and efficient information processing would
be the lifeblood in the oxygen to a healthy post
biological society, So keeping heat to a minimum would be
of the utmost importance. You may say, and I would
(26:34):
agree with you. That's certainly a post biological civilization with
a hundred thousand or million or billion year head start
on us would have almost certainly figured out better, more efficient,
and less heat producing methods for information processing than the
computers we humans have hit upon today. It would be
one of the more surprising things in this whole series
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if that weren't the case. But when you begin to
scale up from the level of server room on word
to capturing the energy of an entire star, even an
almost efficient computer will still have a massive waste heat issue,
and that post biological society will have to deal with it,
and that problem is compounded with each new star and
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each new piece of hardware that's added. Since you have
a finite amount of energy, even if you're a really
big supercivilization, that means that the total amount of competition
you can do is going to be set by temperature.
So if you wait until the universe gets colder, you
can get much more competition done. Some people have suggested
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that perhaps the edge of the galaxy, which butts up
against the coldest regions of intergalactic space, is the best
place to look for other civilizations, since they will have
likely set up shot there to deal with their massive
waste heat problem. But that Oxford group realized that the
optimal place for a post biological society to best deal
with their waste heat is somewhere in time, not space.
(28:00):
M One popular suggestion for the expiration data of the
universe comes about ten billion thousand years from now via
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the heat death of the universe. Every bit of energy
in the universe was released in the Big Bang some
thirteen point seven billion years ago, and the ninete century
we humans it upon the laws of thermodynamics, which had
some bad news about that energy. Over time periods, that
energy will cease as the heat differentials that produce it
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begin to equalize. As every atom in the universe slowly
stops moving, the universe will cool, and eventually the universe
will experience the death of heat, and with the cessation
of the movement of atoms and the particles that make
them up, not life, not computing, nothing will be possible
any longer. Long before the expiration date, the universe will
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still be alive with energy, but much much colder than
it is now. So particularly clever post biological society might
realize that the energy they have available to them could
be captured and stored for use later on, when the
universe is colder and computing is, by extension far more efficient.
So perhaps they built themselves a galaxy's worth of Dyson's
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fears to collect and store the energy from their stars
while the society went to sleep for a billion or
so years. Even a peaceful post biological society would be
forced to protect their energy allotment and their hardware while
they slept, and so they would almost certainly post some
sort of guard like berserker probes to watch over them
and the civilization they'd arranged in store for themselves while
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they slept. Estivation is a kind of hibernation that some
animals do when it's hot out, and the estivation hypothesis
goes fairly far and entering the family paradox. We haven't
been colonized by other civilizations because they're sleeping, So the
estivation hypothesis is that advanced civilizations might actually think that
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it's too sweltering hot right now, it's three degrees above
absolute zero, so they decide to just hide and estivate
until it's cold enough. So in about one point five
trillion years, it turns out that the universe stops getting
colder because of the background radiation from the horizon, and
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at that point it might be rational for the super
civilizision of wake up and they kind of feel the nice,
crisp autumn air or in this case, the very cold
vacuum of a very far future, and start really running recipilizations.
And this might be an explanation of why we're not
seeing any but it doesn't fully resolve the family paradox either.
(30:55):
We should still be able to observe their dicense fears
or other massive engineering projects encircling a star with an
energy capturing devices no small feat. We should be able
to sense such a thing, And indeed, the team of
Japanese researchers scanned a portion of the sky to look
for telltale signs of dicense fheares stars that produce a
normal amount of heat but are unnaturally dim or even
(31:17):
totally dark. They didn't find any, So it doesn't look
exactly like the universe is currently full of sleeping elder
civilizations looking for Disonian artifacts. These massive engineering projects is
a proposed new branch of CETI. Whether civilization is active,
sleeping or extinct, the projects they created would likely endure,
(31:40):
and if we can find those, we found our answer
to the family paradox. But yet again we have found
nothing of the sort. We have an uncovered one scrap
of evidence the universe has ever been colonized. The Fermi
paradox stands stronger than ever. But what if what we're
seeing is an actually the reality of the universe. What
(32:02):
if we're being actively manipulated that somewhere out there the
universe is indeed teeming with life, that there are widespread
engineering projects that litter the galaxies. We just can't see
any of it because we're being prevented from seeing things
as they really are. This is the basis of a
family of answers to the Family paradox called the Zoo hypothesis,
(32:24):
thought up in nine three by m I t astronomer
John Ball. It supposes that we humans are being kept
without our knowledge and some sort of cosmic zoo, and
being observed, maybe even studied, without our awareness. Perhaps we're
being kept in a kind of nature preserve until we
reach some crucial point in our evolution when the secrets
(32:45):
of the universe will be revealed to us. Or maybe
we're meant to stay in a naturally preserved state forever.
Maybe the rest of the universe has been paved over
with dicens fears, every other available planet stripped and deconstructed
for materials, and out of a sense of intergalactic nostalgia,
our planet and the life on it, including us, has
(33:06):
been selected to be kept in a pristine state. The
Zoo hypothesis has some holes in it too, mostly the
same as any other solution to the Family paradox. It
would take only one member of one civilization to shatter it.
The Zoo hypothesis presumes some sort of star Trek like
prime directive to leave us alone, and it would have
(33:28):
to be firmly upheld by all other civilizations in this
galactic club, keeping us in the dark for as long
as humans have been around. There are no options. The
prime directive is not a matter of degrees, it is
an absolute, one would think. Some people object to this
dismissal of the zoo hypothesis. They point to things like
(33:49):
UFO sightings and historical documentation of inexplicable phenomena like the
fifteen sixty one Cathedral of Light over Nuremberg, Germany. All
of this is evidence of past non compliance with this
prohibition on contact with us humans. It's also possible that
Earth was visited in human prehistory as well, and that
there's just no surviving evidence of it. Or maybe we
(34:12):
have received messages and just don't know it yet. Perhaps
they are encoded in our DNA, waiting for us to
find them and make sense of it. There is something
very disconcerting about the zoo hypothesis, the idea that knowledge
we would very much like to have is being kept
from us without our say in the matter, through ways
we may never hope to overcome on our own. But
(34:35):
I don't know. Is that better or worse than the alternative?
Is the idea that we are being manipulated by a
galactic club of civilizations better or worse than the idea
that there are no other civilizations at all. There is
a very reasonable alternative explanation to the Faramie paradox, one
that requires us to make the fewest leaps of faith
(34:56):
to reach it. That we are utterly and entirely alone
in the universe. This is Oxford philosopher Toby Ord. There
are about two hundred billion stars in our galaxy the
Milky Way. So if the chance of life or intelligent
life evolving around any one of those stars was was
(35:19):
even you know, one in a billion, you'd expect that
to be about two hundred stars in our galaxy that
have involved intelligent life. And yet when we look around,
we see no signs of this, and we also don't
see any signs of it in other galaxies um that
we have looked at. Some people think that this is
a paradoxical result, but I think it's actually much more
(35:42):
likely that the that it's just that there aren't any
As Michael Hart puts it, in this Our universe is
too big and too old for it not to be
teeming with life by now. That we've not seen evidence
of other civilizations suggests that they do not exist, but
that's not to say they never did. Perhaps we don't
(36:05):
see other intelligent civilizations because none of them have survived.
On the next episode of the End of the World
(36:26):
with Josh Clark, the great filter is whatever is in
the way, whatever makes it hard for any one piece
of ordinary dead matter to produce expanding, lasting life. If
we are alone in the universe, then perhaps there's something
that's killed off every other civilization before it could spread
from its home planet. And if that's true, can we
(36:47):
expect the same in our future?
This is a love letter to humanity. My name is
Josh Clark, and for the last few years I've been
thinking a lot about how the world might end, and
over the course of that time, I've come to seriously
believe that in a hundred or two years from now,
there's a really good chance that we humans won't be
(00:21):
around any longer, that we will have vanished forever from
the universe, and that it may be us who brings
about our own demise. This series is about the very
real ways that that could happen. It's meant to open
your eyes, hopefully get you to take these ideas seriously too,
(00:44):
and ideally get you to take action. But just as much,
I hope by pointing out just how close we are
to the brink of disaster, you come to feel the
way that I have about your fellow humans and humanity
as a whole. That we are flawed and ugly and brutal,
(01:04):
for sure, but that we are worth fighting to save,
even from ourselves. That the beauty and the love that
humans are capable of creating is greater than the worst
of our faults. That nothing we've done is worth letting
our entire species come to an untimely, impermanent end. It's
(01:25):
a bizarre thing to say, but I found it's worth saying.
Humans don't deserve to go extinct. This series is about
existential risks. We're not used to this kind of risk,
nor are we really equipped to deal with them. I'll
tell you a lot more about them as the series
(01:46):
goes on, but while you listen, try to keep in
mind that no horrible catastrophe, no world war, no epidemic
that's ever come before, nothing we've ever been through has
prepared us to take on existential risks. We have no
frame of reference for them, because the destruction they can
(02:06):
bring is unprecedented in the history of humanity. Yet, and
what maybe the weirdest turn of events in the history
of our species, A whole crop of these new existential
threats are suddenly looming in our near future. Each one
of them could bring about the sudden and permanent end
(02:27):
of the human race. This would be a particularly tragic thing.
We humans have only just begun to live. Human civilization
has been around for about ten thousand years. Think about
what we've accomplished in that relatively short time. Now, think
about what it might be like to be a human
after civilization has been around for a million years or
(02:50):
a billion. So not only are the lives of those
of us around today on the line, but we have
to remember the lives of all the humans to come
are as well, and the stakes for us avoiding extinction
in the next century might be even higher than that.
As we'll see in this episode, we humans may be
the only intelligent life in the entire universe. If we die,
(03:15):
so too does all the things that make us human,
All of the love and compassion, all of the inventiveness
and curiosity, all of it perishes with us, not just
here on Earth, but in the universe as a whole.
It's staggering to think, but the responsibility for our own lives,
for the future of the human race, and for intelligent
(03:37):
life in the universe appears to suddenly rest solely in
the hands of those of us alive today. It would
probably be good to know if we're alone or not,
just for the sake of knowing what's on the line
if we go extinct, So let's start there. As it
turns out, you should know an alien by now, so
(03:58):
should I. By this point in human history, everyone you
and I know should know an alien. We should know
them from work, from your kids school. They should be
our neighbors. Earth should be a melting pot of not
just human cultures, but extraterrestrial ones too. At the very least,
we should be certain by now that there are aliens
(04:20):
out there, just as sure as we know that there
are people living in France and Denmark. We should know
that there are aliens on proximous Centauri B or trappist
One F. And yet we don't, and you and I
don't know any aliens, which is actually very, very weird.
The reason why it's weird is that the universe we
(04:41):
live in is extremely old. It's nearly thirteen and a
half billion years old, and our galaxy, the Milky Way,
is extremely vast from the perspective of us humans. It
takes a beam of light a hundred thousand years to
cross it. And within our very old and very immense galaxy,
there are a lot of stars, between two hundred to
(05:03):
three hundred billion of them three hundred thousand million stars.
Working from the premise that our own stars, light and
heat helped raise life here on Earth, one would think
that somewhere among those three hundred thousand million stars out there,
the same thing would have happened. It happened again and again.
(05:25):
By all rights, even with just a slight fraction of
those stars growing life on a planet in orbit around it,
our galaxy should be teeming with life like mold on
a slice of bread. There's certainly been plenty of time
for it to happen. Here on Earth, life arose within
the last three and a half billion years and managed
to evolve from little strands of proteins into us, sentient
(05:48):
human beings who have come to wonder if the same
thing has happened elsewhere too. Since the galaxy is nearly
four times older than the time it took for intelligent
life to emerge here on Earth, it's had ample time
to emerge elsewhere in our galaxy too. So what we've
got is something of a mystery on our hands. The
universe is by far old enough and definitely large enough
(06:10):
to have produced intelligent life over and over and over again,
and yet we have not one iota of evidence that
we are anything but utterly alone in the Milky Way.
It's become increasingly clear that when we look out at
the night sky, there's nothing looking back at us. This
(06:31):
is the basis of what's come to be called the
Fermi paradox, and it begins, like so many great strange things.
Over lunch in the summer of nineteen fifty four physicists
ambled over to the Fuller Lodge, an old two story
boarding house made of human logs with a big, hulking
(06:54):
stackstone fireplace that you could practically stand up in. The
Fuller Lodge had been converted into a mess all for
the people working on the Manhattan Project at Los Alamos,
New Mexico. Taking a break from refining the most destructive
weapon the world has ever known into an even more
destructive one, these four physicists got into chatting about the
(07:14):
UFO fever that had recently gripped America. They dismissed the
idea that reports of UFOs were in fact alien in origin,
but they didn't dismiss the idea that it was possible
life could exist elsewhere in the universe. It was likely
that it did, they concluded. After the group had already
moved on to other topics, one of them, Enrico Fermi,
(07:35):
abruptly returned the conversation back to aliens. Where is everybody?
He asked, or perhaps, but have you ever wondered where
everybody is. The precise words were lost over time, but
Fermie's three lunch companions all recalled that they knew just
what he meant, and they grasped the implications as well.
There should be life all over our galaxy, and yet
(07:57):
there appears to be only us. Fairmi never formally explored
his question, but it's understandable why it came to be
named after him. As physicists go, Faremi was no slouch.
He presided over the first controlled nuclear reaction created in
a uranium pile of his design, constructed on a squash
court beneath the football field at the University of Chicago.
(08:19):
He calculated formula that helped answer the shape of matter
on the quantum level, and a family of quantum particles
are named after him Fairmians, and of course he helped
build the bomb. But more than Fairmi, it was an
American astronomer named Michael Hart who was really responsible for
the Fermi paradox. In the mid seventies, Heart wrote a
(08:40):
paper called the Explanation for the Absence of Extraterrestrials on Earth.
He summarized and organized the arguments against the paradox, which
come in a rainbow of colors with only a couple
of shapes, and Heart ultimately concluded this because life should
reasonably have emerged and be known to us by now.
The fact that it hasn't solves the family paradox. The
(09:03):
answer is that we are alone. Mystery solved. Michael Heart's
paper struck a blow in particular to the group most
diametrically opposed to his conclusions. City researchers set the search
for extraterrestrial intelligence is an offshoot of astronomy and astrobiology,
(09:23):
and back in the early sixties, astrobiology hit the scientific
scene like a bomb. It was an exciting new discipline
that treated the possibility of extraterrestrial life is real. In
sharp contrast to the people who agreed with Heart, the
astrobiologist camp was populated by optimists who reasoned that it
is simply too unlikely for life to evolved only once
(09:44):
throughout the entire universe. We just needed to hone the
way we search for aliens, and we would surely find them.
Cd He evolved is the intelligence gathering arm of astrobiology,
and set about listening for alien transmissions by aiming radio
telescopes at the center of galaxies that seemed likely to
host life. By the time Michael Hart published his paper
(10:06):
said he hadn't found anything, and Hart included in his
article that said he was an utter waste of time
and resources. By that time, many others, including some in
Congress who funded things like st tended to agree that
there is little justification for twelve million dollars taxpayer dollars
to be expended for this program. Madam President, I urge
(10:28):
my colleagues to vote in favor of this amendment, and
I reserve the balance of my time and yield the floor,
and I thank the chair. Yet neither hearts paper nor
sti's empty handed searches have settled the mystery of the
family paradox. Because we've gotten better at observing our universe,
this little mystery has only gotten more weird. Thanks to
(10:50):
space based telescopes like the Kepler and new methods we've
developed for watching stars, we found that there are a
mind boggling number of potential earthlike planetile there. To qualify
as a potential host for life, the planet has to
check some boxes. The star that it orbits has to
be of a certain type, and in what's called its
main sequence, it helps to be around the size of
(11:12):
our Sun, which is right in the middle. Size Wise,
big stars go through their fuel too quickly to give
life a reasonable amount of time to emerge. On the
other end, smaller stars don't burn quite warmly enough. The
planet has to be a particular distance from the star.
Too too close and any life would be burned to
a crisp Too far away, and the star's warmth couldn't
(11:34):
overcome the unbearable cold of outer space. Either way, the
conditions wouldn't allow for water to form or an atmosphere,
both of which we assume are requirements for life to emerge.
The planet needs to be in a spot relative to
the Sun that's not too hot and not too cold,
but just right for life. So it may not come
as much of a surprise that some astronomers call this
(11:56):
area the Goldilocks zone. Taking all of this in to account,
there are perhaps tens of billions of potentially habitable planets
in the Milky Way alone, and it gets even weirder.
Throughout the decades that people have attempted to resolve the
family paradox, those attempts have always been focused on our galaxy, specifically,
(12:18):
the rest of the universe is just too big to
allow for the time it would take for another civilization
to travel to the Milky Way and make its presence
known to us. So by leaving out the other hundred
billion galaxies in the universe and there's seventy billion trillion stars,
the idea that perhaps other life might exist outside our
own galaxy was allowed to stay aglow as a faint
(12:39):
member of possibility, But in two thousand thirteen that ember
was snuffed too. A pair of philosophers from Oxford figured
out that the math shows there has been plenty of
time for intergalactic civilizations to have evolved and traveled to
our galaxy too. This is one of those Oxford philosophers
under Samberg, actually suppose you wanted to go out and
(13:01):
colonized as far as you could, how far could you go?
And we found that you can literally do this over
billions of light years, which means that this is also
something aliens could have done. So if it's a bit
weird that we haven't noticed in the alien spreading across
the Milky Way, now we need to take into account.
(13:22):
But actually there are also millions or billions of galaxies
where aliens could have come from but they haven't shown
up yet. So when we finished that paper, we kind
of pointed out that we made the Fermi paradox a
million or a billion times worse. The Family paradox extends
not only to our galaxy, but it seems to the
entire visible universe. Hm to a lot of people who
(13:59):
think about this kind thing, it's simply too outlandish to
believe that we are the only intelligent life in the
entire universe, and so over the years, people have put
forth some interesting answers to the family paradox on the
basis that there is intelligent life out there, we just
don't know it yet. At the most basic level, the
(14:19):
arguments consists of the notions that aliens either can't or
won't make the trip to see us. Aliens have had
plenty of time to colonize the galaxy and even the universe,
as we've seen, even considering travel at less than the
speed of light, even travel at ten percent the speed
of light shall allow for the Milky Way to be
colonized in fifty million years at the most. But even
(14:41):
allowing for plenty of time to make the trip, it's
entirely possible that the trips between stars and galaxies is
extremely difficult, so difficult in fact, that no intelligent civilization
has ever successfully managed it, although plenty may have tried
and lost a lot of their people to be impossibly
hazardous trips before finally giving up. Space is far from empty.
(15:04):
It's full of tiny particles called cosmic dust, raw material
that planets are made from. There's a dust cycle out
in space where dust is blasted into space by exploding stars.
This dust fills space, and even though it consists of
extremely tiny particles, it would pose a hazard to any
spacecraft traveling at some significant fraction of the speed of light,
(15:25):
which again, remember something like six hundred and fifty million
miles an hour. Even a tenth of that is still
sixty five million miles per hour. At these speeds, the
spacecraft kinetic energy is so unimaginably huge that a collision
with even some tiny piece of matter would be catastrophic.
MT physicists calculated that impacting even a single grain of
(15:47):
cosmic dust would be tantamount to the explosion of something
like two and a half tons tons of T and
T aboard the ship, and cosmic dust is just one
hazard that space bearing species would have to overcome. There
are surely plenty of others that we haven't learned of yet.
This argument has a flaw to it, though, and I
(16:07):
want you to pay attention to it, because it's part
of a theme that really all arguments regarding the Family
paradox share. If the reason aliens haven't colonized the universe
is because it's extremely hard to travel between stars and galaxies,
that means that it is so hard that not one
single intelligent civilization managed to figure out a way around it,
(16:29):
not one out of the potentially millions or billions or
even trillions that may have evolved over the life of
the universe. This is important because to resolve the Family paradox,
it would take just one of them to have learned
how to survive the trip, to colonize the galaxy and
show us that we are not alone. And you can
argue that it would really only take one, one single
(16:51):
member of one single civilization of the potentially trillions of
them to make it to Earth and make their presence
known to us to have proof that we are the
only intelligent life in the universe, which makes the Fermi
paradox even stranger or more clearly settled, depending on your view.
The other side of that particular coin holds that other
(17:12):
civilizations could colonize the galaxy or even the universe, they
just don't want to. There are a lot of theories
as to why that might be. Now it's possible we're
anthropomorphizing aliens here. We humans will almost certainly colonize the
galaxy if we ever get the chance to. So, perhaps
we're relying too heavily on the assumption that any life would.
(17:34):
This is the senior astronomer at the Study Institute set
show Stack. All of this, all of this is based
on trying to guess, because that's really the correct verb,
to guess what is important to the extraterrestrials. And I
don't think that we're actually very good at that any
(17:55):
anymore than you know, the ancient Greeks would have been
very good at guessing it's important to century Americans. I
don't think that they could have seen foreseen the kinds
of things that would be important to us. Perhaps the
civilization develops to the point where it's technologically capable of
interstellar and intergalactic travel, it loses its taste for such things.
(18:17):
Perhaps the civilization goes philosophical and contemplative a race of
beings who prefer to spend their time thinking about the
meaning of life. You're solving the deepest mysteries of the
universe from home. But even the most inward focused society
would have good reason for expanding from their home planet.
As their population grew, they would need more and more
(18:38):
raw materials to keep them alive while they sat around
in contemplated life. It would be more space, more energy.
The need for scarce resources appears to be one of
the few universal commonalities that any civilization will have to
deal with. This is good. This means that we can
pretty confidently use this clue to predict the behavior of
(18:59):
any intelligen life. Then we humans run into limitations on
our ability to grow or make food, so we need
more space for that. We need space for our bodies
as well, since each person needs somewhere around one point
six one point seven meters of physical space to stand
up and extend our arms with him, plus we tend
to like a little extra to move around into. Requirements
(19:23):
like these mean we would eventually face the prospect of
either systematically curtailing our population growth to maintain no more
than what the Earth can support and based on all
current and historical data, we tend to overstrain the planet
rather than work within its confines, or we can spread out.
It's difficult to imagine that any advanced society faced with
(19:44):
resource pressures would not look out to at least their
own solar system as a source of material solutions to
their problems. This scenario extends further and further, both into
space and time. As the society continued to grow, they
would take up more and more space, and over long
enough spans of time, they should reasonably have colonized a
(20:05):
sizeable chunk of their galaxy, if not the whole thing,
even with their desire to remain inward over so many generations.
But maybe aliens have good reason to resist the urge
to spread out. Maybe they're hiding from something, Maybe they
know something that we don't know. One of the long
(20:44):
standing theories about why a civilization with the capability of
traveling to other stars would opt not to is the
idea that they might be afraid of something. Perhaps there's
some older civilization that doesn't like to compete for scarce
resources with young upstarts like ourselves, the first civilization to
have colonized the galaxy would have all the advantage over
(21:05):
any others that came later, even considering a hundred thousand
year head start, which though it's tough to remember that
the cosmic time scales we're dealing with here is the
blink of an eye, and earlier civilization would have time
to see the galaxy with things like berserker probes, hypothetical
type of self replicating space probe designed to attack and
(21:26):
destroy entire civilizations. These berserker probes would be capable of
strangling in the cradle the colonial aspirations of any younger
civilizations before they ever got started. Right about where we
humans are in our progress right now. What's ironic about
berserker probes is that they can produce their own solution
(21:46):
to the family paradox without even existing. We humans thought
of the possibility that they could exist, so it stands
to reason that other intelligent civilizations might too. It's possible
that part of the process of the umbing and intelligent
society engaged with the unknowns of the universe is to
start having second thoughts about signaling into the void and
(22:08):
instead to go silent. Eventually, every single one of these
societies might stop attempting to communicate and resigned to just
sitting and listening instead. So the universe could be teeming
with intelligent civilizations, each being quiet as a dormouse, each
listening and unaware of the existence of the others, and
(22:29):
the berserker probes wouldn't even have to exist beyond the
hypothetical for this solution to the family paradox to work.
But if berserker probes do exist, why wouldn't we have
had an unpleasant visit from them by now? Transmissions from
our radio and TV shows have been traveling through space
since we first started broadcasting here on Earth in the
early twentieth century, and steady researchers have been actively shouting
(22:52):
at other star systems with radio since the sixties. Probably
the most unsettling answer is that we did get their attention,
and they're on their way. They just haven't had time
to reach us yet, or perhaps they don't much care
about us so long as we stay here on Earth
or even within our own galaxy. In two thousand and seventeen,
(23:14):
Oxford philosophers Stuart Armstrong, Ander Samburg, and Milan Turkovich developed
a new explanation for the Fami paradox that says that
perhaps the universe does contain berserker probes, but rather than
actively patrolling the galaxy, they are posted on the outskirts
of some ancient civilizations state territory while the civilization sleeps.
(23:35):
This new idea, called the estivation hypothesis, supposes that the
civilization in question has reached a post biological state. Post
biological civilizations are their own can of worms entirely, and
we'll talk about them more later on. But what they
amount to is a species that has shed its biological form,
whether it's an upright bipedal form like us humans, a
(23:57):
giant root, vegetable, whatever, and has preserved its minds into
a computerized form. There are myriad advantages to this. Less
physical space is needed, you don't need to grow food.
But these civilizations are not free from scarcity either. Here's
philosopher Ander Samberg again. So suppose you're a really advanced civilization.
(24:19):
You've been around for millions of years, you kind of
explored in the galaxies, You've done most of a big
physical stuff. At this point, probably most of what you
want to do is going to be kind of cultural.
We have no idea as umus what an advancedivils might
want to do. But I think it's a pretty certain
bet that it's going to require competitions of some kind.
(24:40):
Information processing a k. A. Computing has its own requirements.
It needs energy and it produces waste heat, two huge
factors that a post biological society would come up against
as it uploaded more and more of its population to
a digitized format. Rather than food, water, and couple of
square meters of physical space, they would need processing power
(25:04):
and speed to keep their digitized minds humming along and
to simulate the world for them. So a post biological
society would have very good reason to colonize their galaxy
in search of more raw materials to build hardware and
to harness more energy from They will probably build massive
engineering projects to capture energy from entire stars, like through
(25:27):
some variation of Dicen spheres to a hypothetical energy collection
machine that could be constructed around a star to capture
some enormous fraction of its energy. They may deconstruct entire
planets to build those Dicen spheres, so they may have
energy and aces. But at some point a post biological
society might strike upon a seemingly insurmountable truth about information processing.
(25:52):
Regardless of how efficient it is, computing produces some amount
of waste heat. This can be tricky enough with a
single server him here on Earth in the early twenty
one century, those racks of servers have to be cooled
with fans, and the room has to be air conditioned.
So that means that not only is the actual process
of computing taking up energy, there's an additional energy expenditure
(26:14):
required to keep the hardware cool. Heat is the sworn
enemy of efficient information processing, and efficient information processing would
be the lifeblood in the oxygen to a healthy post
biological society, So keeping heat to a minimum would be
of the utmost importance. You may say, and I would
(26:34):
agree with you. That's certainly a post biological civilization with
a hundred thousand or million or billion year head start
on us would have almost certainly figured out better, more efficient,
and less heat producing methods for information processing than the
computers we humans have hit upon today. It would be
one of the more surprising things in this whole series
(26:54):
if that weren't the case. But when you begin to
scale up from the level of server room on word
to capturing the energy of an entire star, even an
almost efficient computer will still have a massive waste heat issue,
and that post biological society will have to deal with it,
and that problem is compounded with each new star and
(27:16):
each new piece of hardware that's added. Since you have
a finite amount of energy, even if you're a really
big supercivilization, that means that the total amount of competition
you can do is going to be set by temperature.
So if you wait until the universe gets colder, you
can get much more competition done. Some people have suggested
(27:36):
that perhaps the edge of the galaxy, which butts up
against the coldest regions of intergalactic space, is the best
place to look for other civilizations, since they will have
likely set up shot there to deal with their massive
waste heat problem. But that Oxford group realized that the
optimal place for a post biological society to best deal
with their waste heat is somewhere in time, not space.
(28:00):
M One popular suggestion for the expiration data of the
universe comes about ten billion thousand years from now via
(28:22):
the heat death of the universe. Every bit of energy
in the universe was released in the Big Bang some
thirteen point seven billion years ago, and the ninete century
we humans it upon the laws of thermodynamics, which had
some bad news about that energy. Over time periods, that
energy will cease as the heat differentials that produce it
(28:44):
begin to equalize. As every atom in the universe slowly
stops moving, the universe will cool, and eventually the universe
will experience the death of heat, and with the cessation
of the movement of atoms and the particles that make
them up, not life, not computing, nothing will be possible
any longer. Long before the expiration date, the universe will
(29:09):
still be alive with energy, but much much colder than
it is now. So particularly clever post biological society might
realize that the energy they have available to them could
be captured and stored for use later on, when the
universe is colder and computing is, by extension far more efficient.
So perhaps they built themselves a galaxy's worth of Dyson's
(29:31):
fears to collect and store the energy from their stars
while the society went to sleep for a billion or
so years. Even a peaceful post biological society would be
forced to protect their energy allotment and their hardware while
they slept, and so they would almost certainly post some
sort of guard like berserker probes to watch over them
and the civilization they'd arranged in store for themselves while
(29:53):
they slept. Estivation is a kind of hibernation that some
animals do when it's hot out, and the estivation hypothesis
goes fairly far and entering the family paradox. We haven't
been colonized by other civilizations because they're sleeping, So the
estivation hypothesis is that advanced civilizations might actually think that
(30:13):
it's too sweltering hot right now, it's three degrees above
absolute zero, so they decide to just hide and estivate
until it's cold enough. So in about one point five
trillion years, it turns out that the universe stops getting
colder because of the background radiation from the horizon, and
(30:34):
at that point it might be rational for the super
civilizision of wake up and they kind of feel the nice,
crisp autumn air or in this case, the very cold
vacuum of a very far future, and start really running recipilizations.
And this might be an explanation of why we're not
seeing any but it doesn't fully resolve the family paradox either.
(30:55):
We should still be able to observe their dicense fears
or other massive engineering projects encircling a star with an
energy capturing devices no small feat. We should be able
to sense such a thing, And indeed, the team of
Japanese researchers scanned a portion of the sky to look
for telltale signs of dicense fheares stars that produce a
normal amount of heat but are unnaturally dim or even
(31:17):
totally dark. They didn't find any, So it doesn't look
exactly like the universe is currently full of sleeping elder
civilizations looking for Disonian artifacts. These massive engineering projects is
a proposed new branch of CETI. Whether civilization is active,
sleeping or extinct, the projects they created would likely endure,
(31:40):
and if we can find those, we found our answer
to the family paradox. But yet again we have found
nothing of the sort. We have an uncovered one scrap
of evidence the universe has ever been colonized. The Fermi
paradox stands stronger than ever. But what if what we're
seeing is an actually the reality of the universe. What
(32:02):
if we're being actively manipulated that somewhere out there the
universe is indeed teeming with life, that there are widespread
engineering projects that litter the galaxies. We just can't see
any of it because we're being prevented from seeing things
as they really are. This is the basis of a
family of answers to the Family paradox called the Zoo hypothesis,
(32:24):
thought up in nine three by m I t astronomer
John Ball. It supposes that we humans are being kept
without our knowledge and some sort of cosmic zoo, and
being observed, maybe even studied, without our awareness. Perhaps we're
being kept in a kind of nature preserve until we
reach some crucial point in our evolution when the secrets
(32:45):
of the universe will be revealed to us. Or maybe
we're meant to stay in a naturally preserved state forever.
Maybe the rest of the universe has been paved over
with dicens fears, every other available planet stripped and deconstructed
for materials, and out of a sense of intergalactic nostalgia,
our planet and the life on it, including us, has
(33:06):
been selected to be kept in a pristine state. The
Zoo hypothesis has some holes in it too, mostly the
same as any other solution to the Family paradox. It
would take only one member of one civilization to shatter it.
The Zoo hypothesis presumes some sort of star Trek like
prime directive to leave us alone, and it would have
(33:28):
to be firmly upheld by all other civilizations in this
galactic club, keeping us in the dark for as long
as humans have been around. There are no options. The
prime directive is not a matter of degrees, it is
an absolute, one would think. Some people object to this
dismissal of the zoo hypothesis. They point to things like
(33:49):
UFO sightings and historical documentation of inexplicable phenomena like the
fifteen sixty one Cathedral of Light over Nuremberg, Germany. All
of this is evidence of past non compliance with this
prohibition on contact with us humans. It's also possible that
Earth was visited in human prehistory as well, and that
there's just no surviving evidence of it. Or maybe we
(34:12):
have received messages and just don't know it yet. Perhaps
they are encoded in our DNA, waiting for us to
find them and make sense of it. There is something
very disconcerting about the zoo hypothesis, the idea that knowledge
we would very much like to have is being kept
from us without our say in the matter, through ways
we may never hope to overcome on our own. But
(34:35):
I don't know. Is that better or worse than the alternative?
Is the idea that we are being manipulated by a
galactic club of civilizations better or worse than the idea
that there are no other civilizations at all. There is
a very reasonable alternative explanation to the Faramie paradox, one
that requires us to make the fewest leaps of faith
(34:56):
to reach it. That we are utterly and entirely alone
in the universe. This is Oxford philosopher Toby Ord. There
are about two hundred billion stars in our galaxy the
Milky Way. So if the chance of life or intelligent
life evolving around any one of those stars was was
(35:19):
even you know, one in a billion, you'd expect that
to be about two hundred stars in our galaxy that
have involved intelligent life. And yet when we look around,
we see no signs of this, and we also don't
see any signs of it in other galaxies um that
we have looked at. Some people think that this is
a paradoxical result, but I think it's actually much more
(35:42):
likely that the that it's just that there aren't any
As Michael Hart puts it, in this Our universe is
too big and too old for it not to be
teeming with life by now. That we've not seen evidence
of other civilizations suggests that they do not exist, but
that's not to say they never did. Perhaps we don't
(36:05):
see other intelligent civilizations because none of them have survived.
On the next episode of the End of the World
(36:26):
with Josh Clark, the great filter is whatever is in
the way, whatever makes it hard for any one piece
of ordinary dead matter to produce expanding, lasting life. If
we are alone in the universe, then perhaps there's something
that's killed off every other civilization before it could spread
from its home planet. And if that's true, can we
(36:47):
expect the same in our future?
The End Of The World with Josh Clark News
Host
Josh Clark
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