Speaker 1: Hey, welcome to Stuff to Blow your Mind. It's Robert
Speaker 1: Lamb again and we have another Vault episode for you.
Speaker 1: This is part three of our series from last year
Speaker 1: on Horror vacuu I I hope you enjoy.
Speaker 2: Welcome to Stuff to Blow your Mind production of iHeartRadio.
Speaker 1: Hey you welcome to Stuff to Blow your Mind. My
Speaker 1: name is Robert Lamb.
Speaker 3: And I'm Joe McCormick, and we're back with part three
Speaker 3: of our series on Horror Vacui or Fear of the Void,
Speaker 3: which we have. We've been mainly focusing I think on
Speaker 3: art and design in the past couple of episodes, but
Speaker 3: today I wanted to take a look at the history
Speaker 3: of the vacuum, and specifically resistance to the idea of
Speaker 3: the vacuum in philosophy and physics. And to begin, I
Speaker 3: was reading at the scientific history of vacuum physics in
Speaker 3: a book called The Void by Frank Close from Oxford
Speaker 3: University Press in two thousand and seven. Frank Close is
Speaker 3: a professor of physics at Oxford. I think emeritis now,
Speaker 3: but anyway, I was reading about this and he included
Speaker 3: a quote from the rig Veda that I thought was
Speaker 3: very interesting. This is from the creation Hymn of the
Speaker 3: rig Veda, which says, in translation, there was neither non
Speaker 3: existence nor existence. Then there was neither the realm of
Speaker 3: space nor the sky, which is beyond what stirred where?
Speaker 3: And I really like this because it I think it
Speaker 3: encapsulates a kind of a fascinated but challenging history of
Speaker 3: attempts to conceptualize empty space, to even imagine what empty
Speaker 3: space would mean if it were to exist, Because I
Speaker 3: noticed kind of a gap here. As far as I
Speaker 3: can tell, most people all around the world today, even
Speaker 3: in various different cultures whatever, really, as far as I
Speaker 3: can tell, don't seem to express any major problems making
Speaker 3: sense of the idea of empty space. Obviously, there is
Speaker 3: a lot we don't know about the nature of space.
Speaker 3: What is space, where does it come from? What different
Speaker 3: kinds of space could there be, and so forth. So
Speaker 3: space is still a vessel of many mysteries. It's not
Speaker 3: like we've got it all solved. But if you just
Speaker 3: simplify the idea to the basics, I and I think
Speaker 3: most people don't have any problem imagining the concept of
Speaker 3: an area of three dimensional space with no particles in it.
Speaker 3: That just yeah, Okay, that makes sense as an idea
Speaker 3: to me. But if you read about how ancient Greek
Speaker 3: philosophers wrote about this question, I do not get the
Speaker 3: impression that the same was generally true for them. Not
Speaker 3: only did many of them deny the possibility of empty
Speaker 3: space existing, sometimes I get the feeling that they are
Speaker 3: struggling to even imagine what the concept would mean. Do
Speaker 3: you know what I'm getting at here, Rob.
Speaker 1: Yeah, Yeah, this is something we talked a little bit
Speaker 1: about off Mike before the episode here. Yeah, it's it's
Speaker 1: kind of complicated. I mean, one level, they're always going
Speaker 1: to be linguistic possibilities in play. For example, I was
Speaker 1: looking into some sources on the void in Chinese philosophy,
Speaker 1: and you run into, for example, that they are separate
Speaker 1: terms for such concepts as emptiness, nothingness, and the infinite
Speaker 1: or the absolute and one source here, I was looking
Speaker 1: at Fan Magois in Frontiers of Philosophy in China from
Speaker 1: twenty ten, contents that their subtleties involved that quote English
Speaker 1: language is unable to capture. So yeah, we have to
Speaker 1: acknowledge linguistic possibilities. But on the other hand, like thinking
Speaker 1: about like what is it as a modern human, Like,
Speaker 1: why do I, like, you have no problem imagining a
Speaker 1: vacuum or or even a void. And I think part
Speaker 1: of it may be like just the mechanical possibilities that
Speaker 1: we have now and the media evidence thereof. So for instance,
Speaker 1: when I think about a perfect vacuum, I can imagine
Speaker 1: a device that mechanically makes it so within say a
Speaker 1: closed space, I can think back to footage of someone
Speaker 1: in a It's not a perfect vacuum, but a place
Speaker 1: that has no air, that's sort of vacuum. Because I
Speaker 1: guess we get into differences too. Are we talking about
Speaker 1: a space without air in which say a scientist in
Speaker 1: a suit may drop a feather and a bowling ball
Speaker 1: and do that whole experiment, or are we talking about
Speaker 1: something that is a true vacuum with nothing in it
Speaker 1: at all, like like an absolute void. And there are
Speaker 1: differences there, but yeah, as far as just like maybe
Speaker 1: it gets into the idea of imagining a space with
Speaker 1: air in it, Like we have this clear idea of
Speaker 1: what atmosphere is and what air is, and we can
Speaker 1: also see and behold and sort of to some degree
Speaker 1: understand the mechanics by which that air may be removed
Speaker 1: from a space, and therefore you could have a space
Speaker 1: where the visible is not present and the invisible has
Speaker 1: been removed as well.
Speaker 3: Yeah, that's a very good point. And I think, for like,
Speaker 3: one major difference may be the unsettled question of like
Speaker 3: whether the air itself has weight for much of human history. Like,
Speaker 3: if you don't have that worked out, it may just
Speaker 3: be harder to imagine what space devoid of even gas
Speaker 3: particles would be. Yeah, but I want to turn to
Speaker 3: some examples that Frank Close looks at in this book,
Speaker 3: especially his first chapter on sort of the ancient history
Speaker 3: of the void in physics, to look at how this
Speaker 3: idea was thought of before the modern era. So the
Speaker 3: pre Socratic Greek philosopher Thales of Militias, who lived from
Speaker 3: the seventh to the sixth century BCE, writing about the
Speaker 3: idea of emptiness or void without substance, is actually kind
Speaker 3: of tempted to ask can there be such a thing
Speaker 3: as nothing? If someone is able to think about it,
Speaker 3: wouldn't thinking about it mean it was something? And again
Speaker 3: this raises an interesting question for me. I mean, my
Speaker 3: initial reaction is just like, well, no, you know, so
Speaker 3: imagine a container with empty space in it. I don't
Speaker 3: think by thinking about that we change the nature of
Speaker 3: what's in the container. But this does kind of raise
Speaker 3: the specter of like if there could be a vacuum
Speaker 3: for people like Thelees. Maybe this has almost more sort
Speaker 3: of totalizing cosmic implications, that the ability of a vacuum
Speaker 3: to exist says something about the universe as a whole,
Speaker 3: not just one region of the universe, say inside of
Speaker 3: a glass bottle or something. So that's one level in
Speaker 3: which I respond. But then on the other hand, I
Speaker 3: can sympathize with thoughts like this knowing some things about
Speaker 3: modern physics, because in a very real sense, empty space
Speaker 3: is I think I can make the argument that it
Speaker 3: is not nothing. Empty space is something even though it
Speaker 3: is not matter. So this may come from a failure
Speaker 3: to distinguish between space and a concept like nothingness, in
Speaker 3: which case, like if you're imagining space is something like
Speaker 3: space has properties, then in fact it couldn't be nothing,
Speaker 3: which is what Theyley's was thinking about.
Speaker 1: Yeah, this perhaps distinction between nothingness and emptiness, this whole
Speaker 1: thing about thinking about it making it maybe less nothing.
Speaker 1: This reminds me of another paper I was looking at
Speaker 1: being in nothingness in Greek and ancient Chinese philosophy by
Speaker 1: Giming shein Philosophy East and West, nineteen fifty one. This
Speaker 1: author points out that in both Chinese Taoism and Greek philosophy,
Speaker 1: you see this culmination of things in nothingness. Quote, nothingness
Speaker 1: is the nature of being in itself, which is absolutely
Speaker 1: transcendent and nameless. So if I'm interpreting this correctly, the
Speaker 1: sort of dual identity of nothingness in these two different
Speaker 1: thought systems, nothingness is ultimately that which comes before substance,
Speaker 1: but also comes before human attributed meaning. So yeah, like
Speaker 1: even thinking about even giving it a name changes the
Speaker 1: nothingness of it, at least from these perspectives.
Speaker 3: Yes, though with Greek philosophy, I know it very much
Speaker 3: depends on which philosopher you're talking about, because a lot
Speaker 3: of these big Greek philosophers, they were emphatic in specifically
Speaker 3: rejecting the idea that the universe could have come from nothingness,
Speaker 3: that there could ever have been nothingness, or that the
Speaker 3: universe would ever disappear into nothingness like that was specifically
Speaker 3: part of what the cosmological history that Theales was arguing for.
Speaker 3: According to Thales, it would be impossible for the universe
Speaker 3: to have come from nothingness, and it would be impossible
Speaker 3: for it to ever become nothing. There's just sort of
Speaker 3: like infinitely the same.
Speaker 1: Stuff without giving into the exacts of it all though,
Speaker 1: when you hear some of these sweeping x nations of what, say,
Speaker 1: the universe would be if it were reduced to a singularity,
Speaker 1: you know that sort of thing like, that's not nothing,
Speaker 1: it's something, but it's such a strange and alien concept,
Speaker 1: so different from certainly our perceivable reality, that it might
Speaker 1: as well be nothing, you know.
Speaker 3: Yes, that's a good point. And of course, again to
Speaker 3: highlight the difference between nothingness and empty space. Nothingness, I
Speaker 3: think is much harder to define. I don't know exactly
Speaker 3: what we mean when we talk about nothingness. It's sort
Speaker 3: of a more slippery, mysterious concept. Whereas empty space. Again,
Speaker 3: it's not that we understand everything about it, but it
Speaker 3: is something that has physical properties and can be manipulated.
Speaker 3: We know some things about.
Speaker 1: It, yeah, like even linguistically. When we talk about vacuum,
Speaker 1: so we've formed an artificial vacuum inside of a reinforced
Speaker 1: steel chamber. Does that steel chamber contain a vacuum, and
Speaker 1: therefore the vacuum is not nothing because it is a
Speaker 1: thing by virtue of being different from everything surrounding it
Speaker 1: because it is contained.
Speaker 3: Yeah. Yeah, well that raises another question of when you
Speaker 3: ask whether a vacuum exists in nature, I mean in reality,
Speaker 3: Whenever we're talking about a vacuum, we're talking about essentially
Speaker 3: low density gas. So and the question is how low
Speaker 3: density does the gas have to get before you are
Speaker 3: comfortable talking about a region of it as a vacuum.
Speaker 3: So like and say the and we can come back
Speaker 3: to this maybe in the next part of the series
Speaker 3: or something. But like in interstellar voids, there are still
Speaker 3: particles floating around out there. They're just very far apart
Speaker 3: compared to much closer to stars or in the atmosphere
Speaker 3: of a planet. But I guess the question would be
Speaker 3: how far apart does every individual particle of matter have
Speaker 3: to get before you say, okay, this is really a
Speaker 3: total vacuum. But to come back to Theales for a second,
Speaker 3: close makes an interesting argument about Thales sort of having
Speaker 3: something in his cosmology similar to to a kind of
Speaker 3: empty space, basically a primeval material or a sort of
Speaker 3: ground state for the universe, and Close argues that for Theyales,
Speaker 3: this ground state of existence was water. This belief is
Speaker 3: related to the fact that we can observe water going
Speaker 3: through phase changes, so we can see water as solid ice,
Speaker 3: as liquid, as water vapor. And Close says that Theales
Speaker 3: assumed that the diversity of forms went on from there,
Speaker 3: and in fact water was the basis of every material
Speaker 3: on Earth. Rocks, plants, air, et cetera. Are all somehow
Speaker 3: water in some extrapolated form, and so he writes, quote,
Speaker 3: space for Theales is as empty as it can be
Speaker 3: when all matter in it has been turned into its
Speaker 3: primeval form, liquid water, like the ocean. Water thus contains
Speaker 3: every possible form of matter.
Speaker 1: I think we've actually discussed this before. Yeah, in connection
Speaker 1: to his work, like you get down to the idea
Speaker 1: of cosmic ocean, of a primordial ocean on which there
Speaker 1: is no land and no being.
Speaker 3: So there are definitely similarities between imagining, say, you know,
Speaker 3: the gods or the Creator or whatever hovering over a
Speaker 3: great void and hovering over a great ocean. That those
Speaker 3: are like similar ideas in some of these ancient cosmologies
Speaker 3: at least, But anyway, going on from there in the
Speaker 3: fifth century BCE. There's another pre Socratic Greek philosopher, Impedicles,
Speaker 3: who argued that there were actually four fundamental forms of matter.
Speaker 3: It wasn't that everything came from water like they least
Speaker 3: thought that there was in fact earth, air, fire, and water.
Speaker 3: And Empedocles notably realized that air was itself a substance
Speaker 3: and not merely empty space. He also believed there was
Speaker 3: no such thing as empty space. But of course the
Speaker 3: discovery that air is not empty space does not mean
Speaker 3: that empty space cannot exist. But then we come to
Speaker 3: the atomists, who are very interesting in their departure from
Speaker 3: these other ways of thinking. So the atomists included a
Speaker 3: number of ancient philosophers like Lucippus, Democritus, and Epicurus, who believed,
Speaker 3: quite remarkably ahead of their time, that all matter is
Speaker 3: actually made up of imperceptibly tiny particles, which they called atoms,
Speaker 3: from the Greek word atomos, which is derived from something
Speaker 3: that means like cannot be cut or basically indivisible. Now,
Speaker 3: of course, today we know that atoms are not actually indivisible.
Speaker 3: They are made up of subatomic particles like protons, neutrons, electrons,
Speaker 3: and even protons and neutrons can be further subdivided, but
Speaker 3: ancient atomists did not have the experimental apparatus needed to
Speaker 3: discover this. Instead, they arrived at the atomic view of
Speaker 3: physics primarily by way of thought, experiments, and everyday empirical observations,
Speaker 3: such as the observation of things like the erosion of
Speaker 3: solid matter in nature. So if you have a great,
Speaker 3: a grand marble staircase, and you notice that over the years,
Speaker 3: the steps on the staircase are eroding. They're sort of
Speaker 3: like sagging in the places where people walk on them. Well,
Speaker 3: they're solid marble. Where are they going? How do marble
Speaker 3: steps wear away over the ages? It must be because
Speaker 3: each person who steps on them removes some tiny, invisibly
Speaker 3: small amount of matter. But that invisibly small amount of matter,
Speaker 3: those little atoms that are taken away accumulate over time
Speaker 3: and the steps are worn down. But importantly for this discussion,
Speaker 3: the atomists believed that there actually is such a thing
Speaker 3: as empty space. In fact, it was core to their
Speaker 3: theory that the universe was composed of atoms in motion.
Speaker 3: Those atoms in motion needed a space through which to move,
Speaker 3: and the atomists argued that if there were already something
Speaker 3: in the place an atom was moving too, the atom
Speaker 3: couldn't move there because then two atoms would be occupying
Speaker 3: the same space at once. So there had to be
Speaker 3: such a thing as empty space. That was the only
Speaker 3: way that such space could come to be occupied. You know,
Speaker 3: there has to be space for things to move into
Speaker 3: where nothing can move. But after this we get back
Speaker 3: to Aristotle, because we mentioned him at the beginning of
Speaker 3: the first episode in this series. For better or worse,
Speaker 3: Aristotle would pretty much have the last word on this
Speaker 3: question for centuries to come, until experiments in the seventeenth
Speaker 3: century would strongly challenge his decree. But Aristotle says there
Speaker 3: is no such thing as empty space. And I was
Speaker 3: reading about the Aristotelian framework or foundation for the science
Speaker 3: of the early modern period in the Cambridge History of Science,
Speaker 3: volume three, edited by Lindberg at All. This was in
Speaker 3: a chapter called Physics and Foundations by the Princeton philosopher
Speaker 3: Daniel Garber, and he makes some interesting points. But reading
Speaker 3: this chapter, this is the way I was thinking about it.
Speaker 3: So when we think of physics today, we usually of
Speaker 3: it as a science contained within certain boundaries, like there
Speaker 3: are certain kinds of questions that are physics questions, and
Speaker 3: there are other questions that are not physics. Is the
Speaker 3: study of properties of matter and energy something like that,
Speaker 3: and that's a huge field, so you can ask tons
Speaker 3: of questions in it, like how are stars formed? Or
Speaker 3: what is the relationship between particle mass and the Higgs field.
Speaker 3: But if in a physics journal today you tried to
Speaker 3: submit a paper on a question like what are the
Speaker 3: basic modes of existence? And what is being? And what
Speaker 3: is the relationship of those things? To say, God, this
Speaker 3: would probably be rejected as outside the scope of the
Speaker 3: physical sciences, you know, like the editors would say, you
Speaker 3: need to submit this to a different journal. However, this
Speaker 3: attempted limitation of scope was not always present in fields
Speaker 3: analogous to physics. Throughout history. There are many times in
Speaker 3: history where these things really kind of blend together, or
Speaker 3: at least philosophical foundations are thought to have relevant things
Speaker 3: to say about physics theories. So these philosophical foundations might
Speaker 3: include religious worldviews. So you could think about the way
Speaker 3: that the scientists of the Islamic world in the Middle
Speaker 3: Ages might have thought of Islam as a theological foundation
Speaker 3: for the sciences or the way that Christian natural philosophers
Speaker 3: of Europe might have thought about Christianity in the same way.
Speaker 3: But in the West there was a major secular philosophical
Speaker 3: foundation of early science also, and that was Aristotelianism, the
Speaker 3: philosophy of Aristotle and a fourth century BCE Greek philosopher.
Speaker 3: And I think it's fair to say that for like
Speaker 3: hundreds of years, in the schools and universities of medieval
Speaker 3: through early modern Europe, the philosophy of Aristotle was not
Speaker 3: taught in the way that it would be taught in
Speaker 3: a college class today. Like today you would teach it
Speaker 3: like here is an interesting piece of intellectual history, maybe
Speaker 3: providing a certain point of view and showing the development
Speaker 3: of how people thought about X, Y or z. Instead,
Speaker 3: I think it was often taught in a way that
Speaker 3: was closer to how people would have thought about the Bible.
Speaker 3: It's like Aristotle said it. That pretty much settles it.
Speaker 1: Yeah, yeah, So you end up with various discussions and
Speaker 1: arguments coming down to either what Aristotle said or disagreements
Speaker 1: over what Aristotle did say or meant, or what he
Speaker 1: would have said or meant about a given topic.
Speaker 3: Right, and to be clear, it wasn't always this way,
Speaker 3: but it wasn't that everybody thought Aristotle was literally infallible.
Speaker 3: But it seems to me like he was often treated
Speaker 3: by the Scholastics as something approaching infallibility, like it was
Speaker 3: just ludicrous to question Aristotle, though in some cases people did.
Speaker 1: So.
Speaker 3: We should discuss what Aristotle said as about the void.
Speaker 3: Aristotle denies the possibility of the existence of empty space,
Speaker 3: specifically in his book Physics Book four, and as is
Speaker 3: so often true with these ancient philosophers, he makes his
Speaker 3: case for the non existence of a vacuum not by
Speaker 3: doing an experiment and describing it, but by cold rationiocination.
Speaker 3: He is going to reason his way out of having
Speaker 3: to believe in empty space. Garber, in his chapter quotes
Speaker 3: a translation of Aristotle for one of his arguments along
Speaker 3: these lines. Aristotle says, now it space or place has
Speaker 3: three dimensions length, breadth, depth, the dimensions by which all
Speaker 3: body is bounded. But the place cannot be body, for
Speaker 3: if it were, there would be two bodies in the
Speaker 3: same place. What in the world then, are we to
Speaker 3: suppose place to be? And the implied answer is nothing,
Speaker 3: So not to kind of interesting contradiction. It seems to
Speaker 3: me at least that we had the atomists pointing to
Speaker 3: the fact that two objects can't be in the same
Speaker 3: place at the same time to prove that there must
Speaker 3: be empty space, because remember, moving particles have to have
Speaker 3: unoccupied space to move into. And here Aristotle is using
Speaker 3: the same premise in a way to say that space
Speaker 3: cannot exist independent of matter, or else it would have
Speaker 3: to occupy the same place as matter at the same time.
Speaker 3: But coming back to close, he summarizes Aristotle's arguments by saying, quote,
Speaker 3: so for Aristotle, logics seem to require that empty space
Speaker 3: cannot be something and therefore is non existent. He defined
Speaker 3: the void as where there is no body, and since
Speaker 3: the basic elements of things exist eternally, there can be
Speaker 3: no place that is completely empty. Aristotle may have been
Speaker 3: getting some mileage here out of confusion over the difference
Speaker 3: between empty space as something and like nothingness as in
Speaker 3: a way meaning non existence.
Speaker 1: Now.
Speaker 3: Garber, in his Physics and Foundations chapter writes that by
Speaker 3: the thirteenth century, writers in the Scholastic tradition in Europe
Speaker 3: who believed in Aristotelian dogmas had begun assuming the existence
Speaker 3: of a natural force known as horror vacui, again a
Speaker 3: phrase that Aristotle himself did not use, but which aligned
Speaker 3: with his teaching on this matter, that nature would not
Speaker 3: permit a vacuum, and the scholastic writers characterize this as
Speaker 3: a force in nature which prevents vacuo from emerging, almost
Speaker 3: like there's sort of a law of nature something going
Speaker 3: on that will not let a vacuum be created, and
Speaker 3: thus forces matter to fill in the gaps. So you
Speaker 3: can pump out that container as much as you want,
Speaker 3: but horror vacue will prevent it from actually being empty inside.
Speaker 3: And another interesting thing I wanted to flag here is
Speaker 3: that Garber notes a conflict between this Aristotelian dogma and
Speaker 3: some religious reasoning that arose in the Church in the
Speaker 3: thirteenth century that have led to the famous condemnations of
Speaker 3: twelve seventy seven, where we've got a bishop condemning Aristotle.
Speaker 3: So to read from Garber here quote one consequence was
Speaker 3: that without space outside of the finite world, not even
Speaker 3: God would seem to be able to move the universe
Speaker 3: if he chose to do so. This apparent consequence of
Speaker 3: Aristotilian doctrine was rejected in the famous condemnation of Aristotle
Speaker 3: by Etienne Tempier, the Bishop of Paris, in twelve seventy seven,
Speaker 3: and then quoting in translation, here we condemned the proposition
Speaker 3: that God could not move the heavens with rectilinear motion,
Speaker 3: and the reason is that a vacuum would remain so
Speaker 3: Garber says, this really kind of put these scholastic Aristotilians
Speaker 3: in a bind, because in some ways they had to
Speaker 3: defend the possibility of some kind of empty space existing
Speaker 3: in the universe, at least potentially for theological reasons, but
Speaker 3: they didn't want to vile the principles of Aristotle, to
Speaker 3: which they were loyal. But anyway, going on, Frank Close
Speaker 3: makes an interesting argument that I think I would agree
Speaker 3: with that we shouldn't be too hard on the prevailing
Speaker 3: Aristotelian belief in horror vacae because without special equipment and experiments,
Speaker 3: I don't know, it really just seems like that from
Speaker 3: everyday existence, like it seems like reality prevents voids from forming.
Speaker 3: Examples given by the ancient philosophers were things like, hey,
Speaker 3: you suck all the air out of an empty wine skin,
Speaker 3: the wine skin collapses like it shrinks in removing the
Speaker 3: air does not result in a void inside the skin.
Speaker 3: It causes the walls of the skin to shrink proportional
Speaker 3: to the amount of air you're able to remove. You
Speaker 3: could also use this belief in nature's hatred for the
Speaker 3: vacuum to explain the workings of pumps and siphons. So
Speaker 3: beyond the fact that Aristotle said it, it just kind
Speaker 3: of seemed right with everyday experience.
Speaker 1: Yeah, I mean, and you're not walking around your home
Speaker 1: and just suddenly walking into a vacuum, right, Like, even
Speaker 1: the empty rooms are are full, They're teeming with matter.
Speaker 1: And these are I think all great examples where you
Speaker 1: could you can imagine someone saying, look proof right here,
Speaker 1: look at this wine skin. If you can form a
Speaker 1: void in this wide skin, then I'll believe you. Otherwise,
Speaker 1: absolutely not.
Speaker 3: So while horror vakae had its critics for a long time,
Speaker 3: I think it's safe to say that it was really
Speaker 3: like the seventeenth century where this idea was laid to rest.
Speaker 3: So coming back to this idea of like when you
Speaker 3: suck on a straw, what is the force that actually
Speaker 3: causes the liquid in your drink to rise up the
Speaker 3: straw into your mouth. You could imagine it as a
Speaker 3: vacuum created that like sort of resists formation and thus
Speaker 3: sucks the liquid up. The same question was actually raised
Speaker 3: around the year sixteen hundred and brought to the attention
Speaker 3: of Galileo. There are some examples of read about this.
Speaker 3: One is an example of I think a scientist sort
Speaker 3: of at the time a natural philosopher who had been
Speaker 3: trying to construct a big siphon and encountered problems at
Speaker 3: a certain height of the siphon. But then I've also
Speaker 3: read about an influence here being people digging wells and
Speaker 3: mine shafts who would try to remove water from these pits,
Speaker 3: using like plunger based pumps to lift the water out
Speaker 3: through a pipe. There was a problem in all these
Speaker 3: cases with the siphons and the pumps. Basically, the pumps
Speaker 3: stopped working after a certain height after the water was
Speaker 3: raised roughly ten point three meters or so, when you
Speaker 3: had ten point three meters worth of a column in
Speaker 3: the pipe, it would stop going higher, wouldn't climb the
Speaker 3: pipe anymore, and instead a gap would appear between the
Speaker 3: water column and the plunger or the piston or whatever
Speaker 3: you're using to pump it out. So what's going on
Speaker 3: here was what was actually limiting the height of the
Speaker 3: water pump system. Well, Galileo investigated this question, and he
Speaker 3: suspected that the force that drew water up through a
Speaker 3: pump or a siphon may in fact be the force
Speaker 3: of horror vacay. So the vacuum is resisting formation and
Speaker 3: thus pulling water up after itself. So when you try
Speaker 3: to run the pump, the fact that the universe is
Speaker 3: resisting creating a vacuum in that space in between is
Speaker 3: forcing water up.
Speaker 1: I love how this also kind of implies that Galileo
Speaker 1: was maybe not solving a physics problem, but responding to
Speaker 1: a pump problem. We get Galileo on the horn. We
Speaker 1: got a problem with this pump here. See if it
Speaker 1: has time he's afternoon to look at it.
Speaker 3: Well, I mean, that's a wonderful thing about Galileo. I mean,
Speaker 3: he was at all ends of the spectrum right working
Speaker 3: on theoretical problems and astronomy and everyday you know, mechanical
Speaker 3: physics problems. But yeah, it is hilarious. Imagine. I don't
Speaker 3: know exactly when this was first raised to him, but
Speaker 3: it's fun to imagine somebody's like trying to get water
Speaker 3: out of their basement or their mind shaft, and they
Speaker 3: were just able to call up Galileo.
Speaker 1: Or maybe he arrives at his end. He's like a superhero.
Speaker 3: Yeah anyway, Yeah, so he imagines that maybe it is
Speaker 3: the force of nature resisting the formation of a vacuum
Speaker 3: that pulls the water up the pipe. But then at
Speaker 3: a certain point, the weight of the water in the
Speaker 3: pipe is too much. There's too much water, and the
Speaker 3: vacuum resistance can't carry it any higher. It has reached
Speaker 3: the limit of the strength of nature's resistance to a vacuum.
Speaker 3: So fascinating question, but Galileo never solved it in his lifetime.
Speaker 3: Enter a couple of other figures. We got a guy
Speaker 3: named Gasparo Berti who lived sixteen hundred to sixteen forty three,
Speaker 3: and Evangelista Torricelli sixteen oh eight to sixteen forty seven.
Speaker 3: That rob I got a picture of Torricelli for you
Speaker 3: to look at here. I think he is incredibly notable
Speaker 3: for having a Batman symbol as a mustache.
Speaker 1: Yeah, certain portraits of this guy have it worse than others,
Speaker 1: but yet it has this I guess it's sort of
Speaker 1: a Van Dyke, though in other portraits it really feels cruciform.
Speaker 1: It feels like I mean, it looks like he took
Speaker 1: a crucifix with flared arms and was perhaps kissing it
Speaker 1: so much that the barber had to shave him around
Speaker 1: that crucifix, resulting in this hairstyle. It's a lot.
Speaker 3: I want my muzzle to make you think of the passion.
Speaker 3: It seems. It is a bold look. So these two
Speaker 3: Italian scientists, a Bertie and Torricelli performed similar experiments in
Speaker 3: the early sixteen forties that would clarify what was going
Speaker 3: on here. Bertie did an experiment with water, and then
Speaker 3: several years later Torcelli did a more definitive and more
Speaker 3: famous experiment with quicksilver, which we know today as elemental
Speaker 3: liquid mercury. So Torricelli's experiment went like this. You would
Speaker 3: get a glass tube about one meter long and fill
Speaker 3: it completely with liquid mercury. So this tube would be
Speaker 3: closed completely at one end and open at the other.
Speaker 3: So you fill it with liquid mercury, and you temporarily
Speaker 3: plug up the open end, so one end is permanently closed.
Speaker 3: One end put a finger over it to close it,
Speaker 3: and then you flip the tube upright vertical and sit
Speaker 3: the open end down in a big basin of more
Speaker 3: liquid mercury. So you got it like a tub of
Speaker 3: liquid mercury. So you flip it up. You have the
Speaker 3: the plugged open end facing down into the lake of mercury,
Speaker 3: and then you unplug it. You remove the finger the plug. Now,
Speaker 3: remember the tube started totally full of mercury, but now
Speaker 3: that it's unplugged, the mercury can flow down into the
Speaker 3: basin with the rest of the mercury. And when he
Speaker 3: tried this, the mercury in the tube did fall, but
Speaker 3: not all the way. It fell to leave a column
Speaker 3: of mercury about seventy six centimeters in height, and then
Speaker 3: a gap for the rest of the tube length up
Speaker 3: at the closed top. So what was the gap, Well,
Speaker 3: Torricelli reasoned that it was actually a vacuum. There was
Speaker 3: effectively nothing inside the tube for those empty centimeters above
Speaker 3: the column of mercury. The other guy, gasparo Berti, had
Speaker 3: performed a similar experiment with water several years before, and
Speaker 3: they both Both of these experiments seemed to provide evidence
Speaker 3: that it was indeed possible for empty space to exist,
Speaker 3: But the question remained, what was holding up the water
Speaker 3: in the tube, and why would the water only rise
Speaker 3: up the tube to a certain height, or, to put
Speaker 3: it in another way, why would the liquid only fall
Speaker 3: down to a certain consistent height in the tube. The
Speaker 3: answer was also illuminated by Torricelli's experiment, for one thing,
Speaker 3: by comparing the difference between the height of a water
Speaker 3: column in a tube and the height of a mercury
Speaker 3: column in a tube. They were different because water and
Speaker 3: mercury have different densities, and so what Torricelli proposed, and
Speaker 3: what in fact was correct, is that the force that
Speaker 3: kept the water or the mercury column raised in the
Speaker 3: tube was actually the force of atmospheric pressure, the pressure
Speaker 3: of the air pushing down on the water or the
Speaker 3: mercury in the basin below. And these tube systems assembled
Speaker 3: by Birdie and Torricelli were actually systems for establishing an
Speaker 3: equilibrium between the weight of the liquid in this column
Speaker 3: in the tube and the weight the atmosphere exerts on
Speaker 3: the liquid in the basin below. The liquid in the
Speaker 3: sealed tube would fall until the weight of the column
Speaker 3: was equal to the atmospheric pressure, and then it would
Speaker 3: float and fall no more, leaving mostly a vacuum in
Speaker 3: the space above. However, there was another question. There was
Speaker 3: the question of what is causing this. It was important
Speaker 3: to demonstrate that the vacuum was not the thing exerting
Speaker 3: the force. Tori Shelley did this with another experiment involving
Speaker 3: two mercury tubes, one with a sort of bulb on
Speaker 3: the sealed top end. And the bulb would mean that
Speaker 3: a greater volume of empty space was left at the
Speaker 3: top when the liquid fell after the bottom was unplugged.
Speaker 3: So would that make the mercury fall to a different level.
Speaker 3: And it turns out the extra empty space did not
Speaker 3: matter at all. The liquid fell to the same height regardless.
Speaker 3: So the force exerted on the column of water in
Speaker 3: the pipe or the tube was not a pull from
Speaker 3: the vacuum. It was not a pull proportional to the
Speaker 3: amount of vacuum created. It was a push proportional to
Speaker 3: the relationship between the atmospheric pressure and the density of
Speaker 3: the liquid. And this was further demonstrated in experiments performed
Speaker 3: by Blaze, Pascal and I think with some input from Descartes,
Speaker 3: but Blaize, Pascal and collaborators testing a similar experiment at
Speaker 3: different altitudes, so you might you test it at the
Speaker 3: foot of a mountain and then go up to the
Speaker 3: top of a mountain and test again and see if
Speaker 3: there are differences. And indeed they found that higher up
Speaker 3: on a mountain, the column of mercury would be lower
Speaker 3: because the atmospheric pressure was lower. And in fact, these
Speaker 3: experiments and the apparatus used the apparatus what's the plural
Speaker 3: of that, apparati or apparatuses. Anyway, this stuff went on
Speaker 3: to become the basis of the invention known as the barometer,
Speaker 3: which is used to detect atmospheric pressure, and for much
Speaker 3: of history, one of the most common liquids used in
Speaker 3: it has been quicksilver or mercury. So people here in
Speaker 3: the seventeenth century had learned a number of things has weight.
Speaker 3: The atmosphere does have weight, and it presses down and
Speaker 3: this affects all different kinds of fluid dynamics in closed containers,
Speaker 3: and at least in an approximate sense, vacuums can be created.
Speaker 3: But the scientific story does not stop there, and maybe
Speaker 3: in the next episode we can get into a little
Speaker 3: more detail on that history, because there's plenty more. But
Speaker 3: also we've got to talk about psychology and horror vacae
Speaker 3: because I don't know about you, but you ever have
Speaker 3: that creepy feeling when you're reminded of like walking around
Speaker 3: at school when there was nobody there, or any other
Speaker 3: place when you were a kid that normally had people
Speaker 3: in it, but then there were no people in it
Speaker 3: and you were there and it just didn't feel right.
Speaker 3: I think about that all the time.
Speaker 1: Yeah, And of course this plays into a lot of
Speaker 1: our horror movies as well, and a lot of our
Speaker 1: fantastic horror scenarios. So we'll discuss some of those. But
Speaker 1: you know, this, coming back to this realization that the
Speaker 1: air has weight, that atmospheric pressure is evolved in these observations.
Speaker 1: It's something that I feel, even as modern humans, we
Speaker 1: have to remind ourselves of this time and time again,
Speaker 1: because we can also fall into that line of thinking
Speaker 1: where we think of an empty room as empty, we
Speaker 1: think of a clear sky as being empty, but of
Speaker 1: course none of those things are empty. All of those
Speaker 1: things are completely filled up with air exerting a pressure
Speaker 1: on us, but a pressure that is so ambient that
Speaker 1: we do not register it as being pressure.
Speaker 3: Absolutely, and the way that this pressure affects other things,
Speaker 3: say like chemical properties. I think about the boiling point
Speaker 3: of water and how that's affected by atmospheric pressure at
Speaker 3: different altitudes, and how that affects something as mundane as cooking.
Speaker 3: How like cooking has to be different at different altitudes.
Speaker 1: Yeah, Ultimately we have to realize that we are creatures
Speaker 1: that evolve to reside within an atmospheric body, and even
Speaker 1: then only certain parts of that atmospheric body. And then
Speaker 1: if we want to bring fire with us and use
Speaker 1: it to boil matter to eat, we have to take
Speaker 1: into account that it's going to boil a little differently
Speaker 1: depending on how far up into that massive body of
Speaker 1: air we travel.
Speaker 3: We discussed this in a couple of episodes a long
Speaker 3: time ago. I think maybe they were the ones about
Speaker 3: sacred experiences on mountaintops people have had. But the fact
Speaker 3: about how you basically like, you can't boil potatoes on
Speaker 3: top of Mount Everest. People have tried. You try to
Speaker 3: boil food to cook it. The problem is the boiling
Speaker 3: point of water after a certain altitude gets too low,
Speaker 3: and so your water is boiling in the pot, but
Speaker 3: it's not hot enough to cook your food, like boiling
Speaker 3: water is no longer sufficiently hot. Well, and of course
Speaker 3: it's boiling. You can't get any hotter than boiling, so
Speaker 3: you're just stuck like it won't cook.
Speaker 1: It's hard to come up with the response to that.
Speaker 1: I'd forgotten about that tidbit regarding cooking potatoes on Mount
Speaker 1: Everest for some reason. That's that's that's that's almost more
Speaker 1: or mind blowing than anything we've we've discussed in this episode. Yes,
Speaker 1: because it comes down to what we were talking about earlier,
Speaker 1: like the perceived world, the world we can relate to,
Speaker 1: versus the world that seems to exist only within the
Speaker 1: lofty conversations of philosophers and scientists. Like the experience of
Speaker 1: boiling potatoes but not being able to cook them through
Speaker 1: that boiling Like that feels like the twilight zone. That
Speaker 1: feels like something that shouldn't be.
Speaker 3: Rod Serling's kind of talking to you about this.
Speaker 1: Yeah, all right, Well we're going to go and close
Speaker 1: this episode out, but we'll be back with more discussions
Speaker 1: of the vacuum, the void, and so forth. In the meantime.
Speaker 1: Right into us, we'd love to hear from everyone out there,
Speaker 1: what are your thoughts about some of the ideas we
Speaker 1: presented in this episode, and hey, we would love to
Speaker 1: hear your cooking anecdotes from different altitudes if you have
Speaker 1: some of those right in. We'd love to hear about
Speaker 1: your mishaps with boiling potatoes and mountaintops. I know we
Speaker 1: have some mountaineers out there.
Speaker 3: Yes, we do.
Speaker 1: Reminder that Stuff to Blow Your Mind is primarily a
Speaker 1: science podcast, with core episodes on Tuesdays and Thursdays. On
Speaker 1: Mondays we do a listener mail episode, on Wednesdays we
Speaker 1: do a short form artifact or monster fact episode, and
Speaker 1: on Fridays we do Weird House Cinema. That's our time
Speaker 1: to set aside most serious concerns and just talk about
Speaker 1: a strange film.
Speaker 3: Huge thanks to our audio producer JJ Posway. If you
Speaker 3: would like to get in touch with us with feedback
Speaker 3: on this episode or any other, to suggest a topic
Speaker 3: for the future, or just to say hello, you can
Speaker 3: email us at contact at stuff to Blow your Mind
Speaker 3: dot com.
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