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