Speaker 1: Hey, welcome to Stuff to Blow your mind. My name
Speaker 1: is Robert Lamb and I'm Joe McCormick, and it's Saturday.
Speaker 1: Time to venture into the Vault. This episode originally aired
Speaker 1: on July and it is about artificial gravity. Yeah, this
Speaker 1: is a really fun episode. Uh, and it's and I
Speaker 1: think it's a great one to to re air here
Speaker 1: as our last Vault episode of But it gets into
Speaker 1: various models for how we could conceivably carry out artificial
Speaker 1: gravity aboard us some sort of an artificial vessel. Now,
Speaker 1: why did you think this would be a great last
Speaker 1: Vault episode of the year. Is that that you expect
Speaker 1: to be floating around the end of December or what? Well, yeah,
Speaker 1: I guess you know your New Year's Eve celebrations, everybody's
Speaker 1: going to feel a little floaty, feel yourself or maybe
Speaker 1: you're gonna feel more drawn to the year. I hope
Speaker 1: everyone's gonna feel a little lighter. You need some centrifugal anchoring.
Speaker 1: That's the other thing. People are may very well feel
Speaker 1: like they've been spun around in some sort of human
Speaker 1: concoction and uh, and they're struggling to to keep their
Speaker 1: feet underneath them. That's going to be the new trendy
Speaker 1: hangover cure. Just get inside your high efficiency washing machine. Absolutely,
Speaker 1: but yeah, this is a great episode. We get to
Speaker 1: talk about a number of sci fi properties. We talk
Speaker 1: a little bit about two thousand and one of Space Odyssey.
Speaker 1: Uh so, hey, everyone, enjoy and we'll catch you on
Speaker 1: the other side. Welcome to Stuff to Blow your Mind
Speaker 1: from how Stuff Works dot Com. Hey you, welcome to
Speaker 1: Stuff to Blow your Mind. My name is Robert Lamb
Speaker 1: and I'm Joe McCormick. And Robert, I know that many
Speaker 1: times you must have imagined what life is like in
Speaker 1: a zero gravity environment, right, Oh yeah, I mean you
Speaker 1: can't help you, You can't help thinking about it as
Speaker 1: you read about space exploration and and engage with with
Speaker 1: various science fiction scenarios. What would it be like to
Speaker 1: to float free, uh, inside of a capsule? Yeah, and
Speaker 1: people obviously imagine the very simple stuff, right, you know,
Speaker 1: floating from one end of the room to the other,
Speaker 1: not being able to walk normally, maybe fear that you
Speaker 1: would experience some motion sickness. You know, many, many people
Speaker 1: who go to space, I think at least half I
Speaker 1: think is the number, experience some kind of space adaptation problem,
Speaker 1: space sickness once they arrive that might go away after
Speaker 1: some time, or you tend to focus on the amazing
Speaker 1: and the horrible ideas, like you know, for instance, how
Speaker 1: fun it would be to drink orange juice and space
Speaker 1: by chasing the globs around the capsule, or the more
Speaker 1: you know, they're definitely horrible or or almost horrible scenarios
Speaker 1: such as, of course, uh, you know, the bone mass
Speaker 1: density loss, as well as the problem of trying to
Speaker 1: poop in a toilet. Right, I thought you were going
Speaker 1: to immediately go to using the bathroom. I was immediately
Speaker 1: going to go to the bathroom, and then I thought
Speaker 1: I should I should reference like the really pivotal problem
Speaker 1: here as opposed to just the one that is difficult. No,
Speaker 1: I mean, going to the bathroom isn't necessarily a big problem.
Speaker 1: You know, you it might not sound all that appealing
Speaker 1: to essentially poop into a vacuum cleaner, but our bag.
Speaker 1: You know, a lot of people maybe that's something they've
Speaker 1: always wanted to try out. It's not necessarily a horrible idea,
Speaker 1: but it will definitely be horrible. I don't know if
Speaker 1: you make a mistake in this process That's where the
Speaker 1: horror stories kick in, is when the the the super
Speaker 1: expensive space toilet malfunctions. The same thing, of course, is true,
Speaker 1: well not exactly the same thing. A similar thing is
Speaker 1: true of you mentioned chasing orange juice globules with your
Speaker 1: mouth to hunt them down. But eating in space, I mean,
Speaker 1: we depend on gravity so much for a lot of
Speaker 1: our eating activity. Keeping food in a container, I mean,
Speaker 1: you just can't compose dishes in space. You've gotta again
Speaker 1: kind of like you poop into a bag. You've got
Speaker 1: to eat out of a bag um, or have something
Speaker 1: that's relatively solid and doesn't have crumbs that are going
Speaker 1: to get everywhere. I mean, can you think about trying
Speaker 1: to salt your food in space? You sort of need
Speaker 1: to like salt into a bag and shake it up
Speaker 1: or something. Yeah, or just have like a hot sauce
Speaker 1: packet that you you add into your own mouth afterwards.
Speaker 1: I feel like I could get buying a number of
Speaker 1: like bagged curries and whatnot. Yeah. Now, of course, another
Speaker 1: thing Astronaut's report about zero gravity environments is that your
Speaker 1: sense of taste is all jammed up, Like you can't
Speaker 1: taste things the way you normally would and part of
Speaker 1: this probably has to do with the fluid redistribution in
Speaker 1: your body that leads your head and upper body to
Speaker 1: swell because you don't have the normal gravity pulling all
Speaker 1: the fluids in your body towards your feet, which your
Speaker 1: body is naturally trying to overcompensate for. Another gravity tidbit
Speaker 1: that that I always find fascinating is that I believe
Speaker 1: Mary Roach pointed this out in their book A Packing
Speaker 1: for Mars. If you're in a microgravity zero gravity environment,
Speaker 1: your bladder doesn't fill up from the bottom up would
Speaker 1: feel like in the center right, It fills like all
Speaker 1: around towards the very center. So you don't realize that
Speaker 1: you need a urinate, uh, typically until you're absolutely about
Speaker 1: to burst, because because we have evolved to sense the
Speaker 1: to detect that the need for our own urination on
Speaker 1: a gravity invite, in a gravity environment, on a on
Speaker 1: a world with gravity, we are creatures of gravity. It
Speaker 1: reminds me of a piece of terminology I haven't really
Speaker 1: thought of since elementary school. But back then, there would
Speaker 1: be a thing that would be like a p quote emergency.
Speaker 1: Remember the emergency? Oh yeah, well, I mean I guess
Speaker 1: if you have kids there's such a thing as an emergency. Yeah.
Speaker 1: I have a five year old son, and so he
Speaker 1: has these where it's like suddenly it's super dire, like
Speaker 1: you have. He has to run outside off the front
Speaker 1: door is closer to him, uh, you know, grabbing himself
Speaker 1: the whole time and going I gotta go pee and
Speaker 1: then immediately paying Um. This is the kind of thing
Speaker 1: adults tend not to experience, unless perhaps you go into space. Right,
Speaker 1: So those are the the less dire things now you
Speaker 1: already alluded to, of course, the deterioration of body tissues,
Speaker 1: loss of bone density, loss of muscle mass, and and
Speaker 1: and all the different negative consequences that happened to the
Speaker 1: body under zero gravity or microgravity conditions. These things can
Speaker 1: really stack up, and it's not a trivial effect. Astronauts
Speaker 1: have to exercise constantly when they're in microgravity environments. They've
Speaker 1: got to spend hours a day working out in these
Speaker 1: weird machines just to try to offset some of the
Speaker 1: damage that's being done to their bodies by the lack
Speaker 1: of gravity in their environment. And it's still not enough.
Speaker 1: I mean, they still come back to back to Earth
Speaker 1: messed up, and they need time to re reacclimate. Hopefully
Speaker 1: they will eventually come back to something like full health.
Speaker 1: But but it's not good for you. Yeah. And and
Speaker 1: of course one of the problems is that uh, astronauts
Speaker 1: want to go back to space, so they're not necessarily
Speaker 1: going to be as forthcoming about the about how they
Speaker 1: drinks at the feeling. Yeah, I guess that is a
Speaker 1: thing to worry about. You'd hope that they'd be accurately
Speaker 1: reporting how bad it is, but maybe they just they
Speaker 1: want to get back up there. Yeah, I mean that,
Speaker 1: that's that's what what I've I've heard is that generally speaking,
Speaker 1: and you don't go to space then and you're you're like, oh,
Speaker 1: that's enough of that. I'm good. An astronaut a person
Speaker 1: it's worth their whole life to do this for not
Speaker 1: even just to do this, but for the chance of
Speaker 1: doing this. Of course they're gonna want to go back.
Speaker 1: So my question is, why don't the people who run
Speaker 1: the I S S. I don't know whoever they are, NASA,
Speaker 1: I guess maybe not NASA space agencies around the world.
Speaker 1: Why don't the people who run our space stations just
Speaker 1: take advantage of the Holtzman effect and put some gravity
Speaker 1: plating in there so that you can walk around like
Speaker 1: a normal Earth humans. A. Yeah, so yeah, you're so
Speaker 1: you're drawing in both Star Trek and Done here, but
Speaker 1: they're they're both prime examples because they're straight into the blender,
Speaker 1: right because this is uh, this is one of the
Speaker 1: key aspects of our science fiction when it comes to
Speaker 1: gravity or lack of gravity and space. They're basically three models.
Speaker 1: Either you're gonna you're gonna try and go hard science
Speaker 1: and have some sort of an artificial gravity scenario like
Speaker 1: some of the realistic scenarios we're going to discuss in
Speaker 1: this podcast. You're gonna just go you know, micro gravity
Speaker 1: zero G and have people floating around, which of course
Speaker 1: can be difficult from a special effects standpoint. Or you're
Speaker 1: gonna go space wizards. Yeah, you're just gonna go magic
Speaker 1: artificial gravity and just say hey we let's Star Trek.
Speaker 1: We have gravity plates in the floor. Of course there's gravity. Uh,
Speaker 1: it's the in in in in Dune. You have the
Speaker 1: the Holtzman effect generated by the Holtzman field generator, and
Speaker 1: Herbert never explain exactly what it was or how it worked,
Speaker 1: but it allowed for the generation of anti gravity, faster
Speaker 1: than light travel, personal shields, artificial gravity on ships, you know,
Speaker 1: all the things you need to sort of go ahead
Speaker 1: and establish your interstellar uh empire and then tell the
Speaker 1: stories you want to tell. You know, I'm okay with
Speaker 1: that be because in lots of science fiction stories, essentially
Speaker 1: they're trying to tell a character drama or it's a
Speaker 1: fantasy story set in space. I don't need all science
Speaker 1: fiction to be hard science fiction, but I really do
Speaker 1: appreciate hard science fiction that tries to take the physics
Speaker 1: that we know seriously. This does not, But that's okay,
Speaker 1: you know, that's doing its own thing. Yeah. I mean,
Speaker 1: Herbert had areas that he was definitely going to focus
Speaker 1: in on, such as ecological issues, philosophical, religious, cultural issues,
Speaker 1: and of course this the drama that is especially seen
Speaker 1: in the first book. So I kind of slack. Yeah,
Speaker 1: I'm fine with some magic anti gravity. Now, in terms
Speaker 1: of sci fi properties that do take it really seriously.
Speaker 1: What are what are a few films that come to mind? Well,
Speaker 1: of course, you you immediately think of two thousand one
Speaker 1: of Space Odyssey. Now that's got multiple spacecraft. There's a
Speaker 1: space station and there's a spacecraft that both use something
Speaker 1: we're going to talk about later in the episode, rotational
Speaker 1: UH structures for centripetal force driven or centrifical, centrifugal or
Speaker 1: centripetal force driven artificial gravity scenarios. Also, there is a
Speaker 1: good artificial gravity ship in the Martian UH, and I remember,
Speaker 1: I think there's one in a space station, and Interstellar
Speaker 1: isn't there? Yes, I do believe, I remember the spinning situation.
Speaker 1: And I also want to point out James S. A.
Speaker 1: Corey's Expanse series, both the books and the sci fi
Speaker 1: TV show, which which does I think a really good
Speaker 1: job of going after from near future interplanetary culture and technology.
Speaker 1: And it's also the only sci fi property that I
Speaker 1: can think of that that actually explores one of the
Speaker 1: anti gravity schemes that're gonna we're gonna be discussing today.
Speaker 1: Linear acceleration. Well, linear acceleration, I can see why that's
Speaker 1: limited because it has sort of limited applicability if you're
Speaker 1: going to try to be real about like it only
Speaker 1: works in certain types of ships doing certain types of
Speaker 1: things to a certain extent. We can we can chat
Speaker 1: about this this this later. Okay, we'll correct me. Well,
Speaker 1: I don't know, but it's not really correction. But I
Speaker 1: think one of the problems is that linear acceleration model
Speaker 1: calls for a spaceship that is not a seagoing vessel
Speaker 1: transported into space, because, as I said before in the program,
Speaker 1: I think a lot of our science fiction are sci
Speaker 1: fi ships are essentially seagoing vessels and tales of seagoing
Speaker 1: vessels and seagoing captains, uh, taken from Earth and transposed
Speaker 1: into space. I mean that was basically Gene Roddenberry's a
Speaker 1: whole deal with Star Trek that it was was the
Speaker 1: Master and Commander books that he wasn't No, it was
Speaker 1: a different one. Um. I can't remember the series offhand,
Speaker 1: but anyway, he was inspired by by literary tales of
Speaker 1: of of adventurous humans at sea. Uh no, well maybe
Speaker 1: I don't know. Well I guess is yeah, from Hell's Hired.
Speaker 1: I stabbed at the right. But it's it's more difficult
Speaker 1: with linear acceleration because you have to have to take
Speaker 1: that concept of an Earth vessel and you really have
Speaker 1: to literally turn it on its side. You have to
Speaker 1: think instead of a ship going from port to port
Speaker 1: and stopping, you have to think about long continuous journeys.
Speaker 1: But we'll get into all that in a bit. Okay, Well,
Speaker 1: I guess we should first just take a real quick
Speaker 1: look at what is the problem with artificial gravity, with
Speaker 1: generating gravity and space. Why can't you just do it? Well,
Speaker 1: I mean, so, gravity is something that is a field
Speaker 1: generated by generally we think of it as mass. It's
Speaker 1: generated by the stuff in the universe, energy and mass,
Speaker 1: you know, much more by matter that has mass. So
Speaker 1: we all know that objects that have mass have a
Speaker 1: mutual attractive force. They tend to attract one another. And
Speaker 1: you know, we've known this for a long time. It
Speaker 1: was the laws of gravitation were to a certain extent
Speaker 1: well explained by Newton in the seventeenth century, and he
Speaker 1: basically described the laws of gravitation in a way that
Speaker 1: that makes sense for most of the stuff we're going
Speaker 1: to be looking at, for planets, for space ships, for
Speaker 1: things like that. Now. Off later, Albert Einstein revolutionized our
Speaker 1: understanding of what gravity is by telling us that gravity
Speaker 1: is the curvature of space time, and that sort of
Speaker 1: matter tells space time how to curve, and that the
Speaker 1: curvature of space time tells matter how to move right
Speaker 1: So let's start with mask because I think that's the
Speaker 1: that's that's the essential part. That's that's a pretty easy
Speaker 1: to understand here. So everything with mass, from a dust
Speaker 1: moat to a star, exerts a gravitational pull. The strength
Speaker 1: of the poll, however, increases with mass and proximity to
Speaker 1: the object. So a smaller object can only attract another
Speaker 1: small object of it's nearby, but a large opect can
Speaker 1: pull in objects from across the vast distance. Right, And
Speaker 1: this is kind of this is key to the structure
Speaker 1: much of the structure of our of our universe. I mean,
Speaker 1: this is how accretion occurs with little specks of space
Speaker 1: dust and gas forming together and snowballing into larger cosmic bodies. Yeah,
Speaker 1: I mean, this is how our solar system was created.
Speaker 1: Was the coalescing of objects by the force of gravity.
Speaker 1: Things are attracted to each other, eventually becoming stars, planets
Speaker 1: all that. Yeah, And then alert Einstein's general theory of
Speaker 1: relativity comes along and propose that the gravity is a
Speaker 1: curve in the fourth dimension of space time. And there's
Speaker 1: proof to back him up. Given sufficient mass, an object
Speaker 1: can cause an otherwise straight beam of light to curve
Speaker 1: astronomers called this effect gravitational lensing. Yeah, this was shown experimentally.
Speaker 1: It was one of the first big experimental proofs of
Speaker 1: Einstein's theory of relativity. Is that you could see light
Speaker 1: from stars passing behind the Sun bending as it came
Speaker 1: right around the Sun. So you know, if you could
Speaker 1: have a solar eclipse and shield out the light from
Speaker 1: the Sun, you could see stars in the background being
Speaker 1: warped by the Sun's gravity as the beams of light
Speaker 1: passed close to our Sun. Yeah. And similarly, the less
Speaker 1: gravity there is, the slower time passes. And this is
Speaker 1: a phenomenonme is gravitational time dilation. This is this is
Speaker 1: the less key to what we're talking about. But it
Speaker 1: just drives home like the place of gravity, uh in
Speaker 1: our universe. Yeah, it sounds this is one of those
Speaker 1: things that sounds like fantasy, but it's absolutely true. And
Speaker 1: you saw that. We mentioned the movie Interstellar earlier. There's
Speaker 1: actually there are a couple of great scenes and the
Speaker 1: demonstrate this where they go down to a planet with
Speaker 1: an incredibly high gravitational pull and uh, while they're down
Speaker 1: there on the planet, much less time passes for the
Speaker 1: people on the planet than passes for people in orbit
Speaker 1: farther away. Yeah, As a physicist Paul Davies points out,
Speaker 1: time runs a little bit faster in space than it
Speaker 1: does down on Earth. It runs a little faster on
Speaker 1: the roof than it does in the basement, and that's
Speaker 1: a measurable effect. Then's the basics on gravity. But then
Speaker 1: there's also this additional area of quantum gravitation and the
Speaker 1: idea that that there is a there's a hypothetical particle,
Speaker 1: the graviton, which in theory could cause optics to be
Speaker 1: attracted to one another. Yeah, and this would be the
Speaker 1: mediating particle of the force of gravity, in the same
Speaker 1: way you've got like the electromagnetic force, the mediating particle
Speaker 1: there is the photon. Hypothetically you'd have some mediating particle
Speaker 1: delivering the force of gravity. But we've never seen gravitons
Speaker 1: in the universe. Right. This is this whole hypothesis comes
Speaker 1: together because quantum theory, to refresh, addresses how the universe
Speaker 1: works at the smallest subotanic levels, and the resulting model
Speaker 1: here does not explain gravity. So gravitons and the theory
Speaker 1: of quantum gravity is an attempt to reconcile general relativity
Speaker 1: with quantum theory. It's a basically an attempt to patch
Speaker 1: up a hole in the standard model of particle physics,
Speaker 1: which cannot explain gravity. Now, the last time I read
Speaker 1: seriously about gravitons was a few years ago. I wonder
Speaker 1: if any recent experiments in our particle colliders have have
Speaker 1: shed any light on that. I mean, our physicists now
Speaker 1: thinking gravitons are more likely or less likely. So well,
Speaker 1: we certainly don't have any definitive proof on the matter yet.
Speaker 1: But I guess for the purposes of our discussion here,
Speaker 1: since we don't have proof of gravitons, we can't really
Speaker 1: come up with a scheme to employ them or manipulate
Speaker 1: them in some way that would give us artificial gravity. Yeah, so,
Speaker 1: I guess are the point of our bringing up gravitons
Speaker 1: is that you can't just wave a magic wand and say,
Speaker 1: ah ha, gravitons will be the thing we use to
Speaker 1: create artificial gravity in space. I mean, we don't know
Speaker 1: if they exist. If they do exist, I'm not sure
Speaker 1: anybody has a coherent idea of how they could be
Speaker 1: harnessed to provide artificial gravity in space. It just seems
Speaker 1: like I don't know what is So if they're generated
Speaker 1: by mass, would you not need mass to generate them? Yeah,
Speaker 1: I could. I looked around in my research and I
Speaker 1: couldn't find any, like, any real theories about how gravitons,
Speaker 1: if they exists, might be utilized in this fashion. And
Speaker 1: I'm not I'm not aware of any science fiction that
Speaker 1: explores the possibility, but I would love to know about it.
Speaker 1: I think when it does, it's more just the kind
Speaker 1: of it's the handwaving magic. Right. So we come back
Speaker 1: to mass, then yeah, you could, I guess, have a
Speaker 1: spaceship that's as massive as the Earth, and then that
Speaker 1: would have that would give you the gravitational pool you need.
Speaker 1: That's not exactly a terrible idea, and it's not unexplored.
Speaker 1: I mean there have been these ideas, for example, in
Speaker 1: you know, stellar engineering projects that say, hey, so let's
Speaker 1: say we want to travel to another solar system, wouldn't
Speaker 1: it be easier instead of trying to build an arc
Speaker 1: ship to take us there, to see if we can
Speaker 1: build a structure around the Sun that will reflect some
Speaker 1: of its radiation and allow us to steer the movement
Speaker 1: of the entire solar system. Oh yeah, yeah, I just
Speaker 1: move the solar system. Yeah, so like the solar system
Speaker 1: becomes our spaceship. You can build these things called a
Speaker 1: hypothetical structure called a Scatow thruster. Essentially, it would just
Speaker 1: drive the sun. Yeah. That actually features into No Surprise
Speaker 1: and Ena in Banks book, but I'm not going to
Speaker 1: say which one because it's kind of it's kind of
Speaker 1: a spoiler. Okay, but it's one of them. Leave it,
Speaker 1: leave it there. Yeah, So that is one idea though.
Speaker 1: If you wanted to travel through space on an object
Speaker 1: that has Earth gravity, you could just take Earth with you.
Speaker 1: Of course, it wouldn't really make sense to say, well,
Speaker 1: I want to build a spaceship that generates Earth gravity
Speaker 1: through natural mass generating effects, because then you would just
Speaker 1: be building a spaceship the mass of Earth. Right, And
Speaker 1: if you can do that, then, uh, I mean you're
Speaker 1: already you're already a pretty powerful civilization. I'm not sure
Speaker 1: where you would rank on the Cardassi of scale, but
Speaker 1: you'd be you'd be potent. That'd be definitely a Cardassi
Speaker 1: of one, maybe a Cardassi of two. All Right, so
Speaker 1: we've talked about these scenarios involving natural gravity and and
Speaker 1: the idea of manipulating natural gravitational forces. Luckily we're not
Speaker 1: We're not forced to contend only with those. We can
Speaker 1: also deal with artificial gravity, not in a magic sense,
Speaker 1: but in a but in a real sense. Yeah, and
Speaker 1: and this way, there are ways to generate artificial gravity
Speaker 1: that are not hypothetical or speculative at all. I mean,
Speaker 1: this is totally easy, standard settled physics, because one of
Speaker 1: the insights of modern physics is that gravity is in
Speaker 1: fact indistinguishable from acceleration. When you're being pulled toward a
Speaker 1: planet's center and the planet has a mass such that
Speaker 1: it generates a surface gravity of nine point eight meters
Speaker 1: per second per second, which is what Earth's surface gravity is, right,
Speaker 1: or whether you're accelerating through space at an acceleration rate
Speaker 1: of nine point eight meters per second per second, the
Speaker 1: effect you experience is exactly the same. You can't tell
Speaker 1: the difference between these two situations. And so knowing this,
Speaker 1: we could turn the idea of acceleration to our advantage.
Speaker 1: And that's where our first model comes into play. But
Speaker 1: first we're gonna take a quick break than alright, we're back.
Speaker 1: So The first model of artificial gravity we're going to
Speaker 1: discuss here is the one that I alluded to earlier
Speaker 1: and discussing the expanse, and one that I think by
Speaker 1: and large, bab, I cannot think of another single science
Speaker 1: fiction property that employs this as their artificial gravity on
Speaker 1: a spaceship. But yeah, linear acceleration, I can't really think
Speaker 1: of many that do. But so, what's the basic idea here, Robert?
Speaker 1: All Right, So, if you've ever written on a roller
Speaker 1: coaster and felt yourself plastered to the back of the seat,
Speaker 1: then you've experienced some of the power here. If you
Speaker 1: were in a fighter jet and you were, you know,
Speaker 1: traveling at a sufficient speed to pull you multiple g s,
Speaker 1: you're you're also experiencing this as you're pushed back into
Speaker 1: the chair. Right, So, if you can imagine being in
Speaker 1: that fighter jet and you're being pulled back into your chair,
Speaker 1: except instead of going back into your chair, you put
Speaker 1: your feet on the chair, put your head in the
Speaker 1: direction that the fighter jet is going, and the acceleration
Speaker 1: rate of that fighter jet is nine point eight meters
Speaker 1: per second per second, it would suddenly feel a lot
Speaker 1: like it feels to stand on the ground. Right, Imagine
Speaker 1: a skyscraper as a rocket ship. Imagine it blasting through
Speaker 1: space at such a speed that the G force uh
Speaker 1: equaled the pull of Earth's gravity on the internal environment.
Speaker 1: I'm actually gonna read a couple of quick quotes from
Speaker 1: James S. A. Corey's Uh First Expanse novel, because I
Speaker 1: believe that these really capture what we're talking about. So
Speaker 1: he's describing the Donager space ship here quote. Like all
Speaker 1: long flight space craft, it was built in the office
Speaker 1: tower configuration. Each deck one floor of the building. Ladders
Speaker 1: or elevators running down the axis. Constant thrust took the
Speaker 1: place of gravity. Now there's also a Mormon generation ship
Speaker 1: in the book that uses both linear thrust and a
Speaker 1: rotating wheel, which we'll get into, and this is the
Speaker 1: description for it. Each compartment within the massive rings was
Speaker 1: built on a swivel system that allowed the chambers to
Speaker 1: re orient to thrust gravity when the ring stopped spinning
Speaker 1: and the station flew to its next work location. Okay,
Speaker 1: So by describing these ships with floors like an office building,
Speaker 1: what you what you should really picture is like you've
Speaker 1: got a skyscraper and it's flying through space with the
Speaker 1: top of the skyscraper as the front the nose of
Speaker 1: the ship, and all of the floors are where your
Speaker 1: feet would be towards the back of the ship, and
Speaker 1: your head would be facing the front of the ship.
Speaker 1: It's taking the holes like Starship Enterprise situation and turning
Speaker 1: it sideways. If you imagine the Starship Enterprise flying in
Speaker 1: such a way that the top of the ship is
Speaker 1: the front of the ship. I realized this gets complicated
Speaker 1: when you're talking about outer space. But you're you're taking
Speaker 1: and in this part of the problem. Like we we
Speaker 1: understand the movement of things in our situational uh positioning
Speaker 1: in a gravity rich world, and when we try and
Speaker 1: take it out of that, it's it's kind of hard
Speaker 1: to picture some of these, uh these situations. Right. But yeah,
Speaker 1: So if this is taking place in space, you would
Speaker 1: be able to generate a force towards the floor that
Speaker 1: simulates Earth gravity. Now, this would this would have some complications,
Speaker 1: I'm imagine because in order to perfectly simulate Earth gravity,
Speaker 1: maybe you don't care how perfect it is, but if
Speaker 1: the goal was to perfectly simulate Earth gravity, you would
Speaker 1: need to be constantly accelerating at nine point eight meters
Speaker 1: per second per second, that's a lot of constant acceleration.
Speaker 1: You're always going that much faster. Yeah, I mean we
Speaker 1: we see the required propulsion at work when a chemical
Speaker 1: rocket creates enough for us to counter this gravitational pull
Speaker 1: and achieve escape velocity. But they're only achieving it from
Speaker 1: a matter of seconds or minutes. For our spaceship here
Speaker 1: are theoretical spaceship, our office building on its side, you'd
Speaker 1: need something more constant. So, just to refresh on the
Speaker 1: g's here. Standing on the Earth, you'd experience one G
Speaker 1: in free fall, saying an elevator or the vomit comet,
Speaker 1: you'd experience zero G. At two G feel twice as heavy.
Speaker 1: So you'd need a spaceship capable of propelling you fast enough,
Speaker 1: like you said, to exert a constant one G. Yeah.
Speaker 1: So one of uh, the sources we turned to for
Speaker 1: this was a wonderful too thousand seven book Artificial Gravity,
Speaker 1: edited by Giles Climate and Angelie Buckley, And there's an
Speaker 1: article in there by Buckley, Climate and William Pulaski of
Speaker 1: NASA's Johnson Space Center, and uh, they point out that
Speaker 1: a spaceship could in theory accelerate for the first half
Speaker 1: of a Mars journey, then decelerate on the second half,
Speaker 1: and in doing so maintain one G and reach Mars
Speaker 1: in two to five days, depending on the distance. I
Speaker 1: mean that would be you'd have to have incredible power, yes,
Speaker 1: incredible thrust to like a powerful fuel to accelerate that much. Also,
Speaker 1: I'm how did so do they explain how you do
Speaker 1: the flip over? You'd have to be accelerating one g
Speaker 1: the like half the way there, and then you have
Speaker 1: to be decelerating at one G the other half of
Speaker 1: the way there, which means I guess you'd have to
Speaker 1: flip the spaceship around so that the floors stays the floor. Yeah,
Speaker 1: Or you'd have to have some sort of like an
Speaker 1: intern habitat that's like a capsule on that rotates. Or yeah,
Speaker 1: I guess you could have a spaceship where the floors
Speaker 1: and ceilings are both can both work as floors, right,
Speaker 1: And of course the distance here involved not to go
Speaker 1: into the Mars opposition details here too much, but the
Speaker 1: maximum distance between these two planets is two hundred and
Speaker 1: fifty million miles with the Sun between the two. So
Speaker 1: I guess that's not doable in two to five days.
Speaker 1: The yeah, I would assume you would not try and
Speaker 1: make the journey there unless I mean, but but if
Speaker 1: you're achieving speeds like that, then you know, maybe you'd
Speaker 1: go you'd go for it. But that the average distance
Speaker 1: is more like one forty million miles and the closest
Speaker 1: possible distance is a tantalizing thirty three point nine million miles.
Speaker 1: But anyway, that's this is the basic Yeah. But yeah,
Speaker 1: you would need to have, uh, some pretty awesome power
Speaker 1: at your disposal, so awesome that I believe in the
Speaker 1: Expanse books like they basically can't be the authors who
Speaker 1: publishes as as James S. A. Corey, Uh, they had
Speaker 1: to sort of create their own fictionalized propulsion breakthrough to
Speaker 1: make that possible. Here's where you need the magic in
Speaker 1: this version. Yeah, instead of having magic gravity plating, you
Speaker 1: have magic propulsion. And I guess is the case with
Speaker 1: a lot of sci fi Like you, there's a certain
Speaker 1: place you you want human civilization and or alien civilizations
Speaker 1: to be at, you know, to be able to discuss
Speaker 1: them and look at the ramifications. But yeah, we don't
Speaker 1: have all the steps worked out about how we'd get there.
Speaker 1: There's there are certain breakthroughs that we need to take place,
Speaker 1: and you could explore them and try and come up
Speaker 1: with some sort of uh, you know, complex of physics,
Speaker 1: space theory, or you could just you know, put a
Speaker 1: posted note there and and maybe write magic on it. Yeah.
Speaker 1: Even in a lot of so called hard sci fi
Speaker 1: or mostly hard sci fi, you know, you've got like
Speaker 1: a list of steps in how something is achieved, and
Speaker 1: most of the steps are something that's scientifically rigorous, but
Speaker 1: one of the steps in the middle is like, here's
Speaker 1: a magical element. I mean, it's kind of like a
Speaker 1: lot of speculative properties that I enjoy. Sometimes there'll be
Speaker 1: something completely ridiculous, uh, something completely magical, But then you
Speaker 1: discuss all the real world ways it might play out.
Speaker 1: Like one example that comes to mind is a World
Speaker 1: War Z you know, the Zombie book. Not so much
Speaker 1: of the movie, but the book looked at it's some
Speaker 1: possible ideas for how this would play out, like culturally
Speaker 1: and politically, without really getting bogged down in the fact
Speaker 1: that zombies are are kind of a dumb I can't
Speaker 1: actually exist. But it's like, roll with me. Zombies are real.
Speaker 1: Let's discuss how this might work. I want to defend
Speaker 1: zombies just a little bit. There are different types of
Speaker 1: zombie scenarios, and some some are much more plausible than others.
Speaker 1: Reanimated corpses, no, but you know, rage zombies, some kind
Speaker 1: of weird virus Okay, maybe, okay, all right, yeah, I
Speaker 1: mean we have rabies. I mean we don't have rabies,
Speaker 1: but there is you never know, alright, so you're probably wondering. Okay,
Speaker 1: we've established how this would work with talked a little
Speaker 1: about the sci fi, but what kind of work has
Speaker 1: actually gone into testing it. Well, there've been at least
Speaker 1: a couple of experiments. The European Space Agency e s
Speaker 1: A experimented with this in nineteen eighty five on the
Speaker 1: Space Lab D one. Now I couldn't find an image
Speaker 1: of it, but I'm assuming it's it's the same sled
Speaker 1: or one similar uh that was used in the Night
Speaker 1: one experiment where they were, you know, messing with the
Speaker 1: nineteen eight one. It's basically this this chair on a
Speaker 1: if you okay, imagine a short train track that you
Speaker 1: could fit in a room and then you have a
Speaker 1: chair on it. I'm glad, I'm glad you've provided this picture.
Speaker 1: But this is crazy. It is. It looks crazy. There's
Speaker 1: so there's a imagine a little train on a little
Speaker 1: train car and there's a chair on it, and the
Speaker 1: chair swivels, and you have somebody strapped into the chair
Speaker 1: with a bunch of you know, electronic dude dads connected
Speaker 1: to them, and then they would, uh, they would essentially
Speaker 1: like fly back and forth on this little train track
Speaker 1: with the with the seat swiveling along the way. It's
Speaker 1: a very Terry Gilliam can traption, isn't it? Yes, it
Speaker 1: it does. It looks very Terry Gilliam. Now they tried
Speaker 1: this out and it peaks speeds. It only provided point
Speaker 1: to G and according to a Clemon company, the threshold
Speaker 1: for the perception of linear acceleration in humans is on
Speaker 1: the order of point zero zero seven G, and the
Speaker 1: threshold for humans in space seems to be more like
Speaker 1: between somewhere between point twenty two and point five G. Yeah.
Speaker 1: I've got some notes about that later on, about what
Speaker 1: exactly would be tolerable as artificial gravity, But I don't know,
Speaker 1: maybe maybe maybe you're getting to it right now. So
Speaker 1: you the the idea here is that you wouldn't necessarily
Speaker 1: have to have one full G in order to counteract
Speaker 1: some of the worst effects of microgravity. Yeah, it kind
Speaker 1: of comes down to what are you looking to do?
Speaker 1: Are you looking to to to counteract the effects of
Speaker 1: microgravity to a certain extent to like just get you
Speaker 1: there a little bit or have like a perfect Earth simulation, Right?
Speaker 1: Do you want to, um, you know, awaken a coma
Speaker 1: pace a board your spaceship and trick them into thinking
Speaker 1: that there's still on Earth. Like that's a tricker scenario.
Speaker 1: I mean, maybe you could do it by telling them
Speaker 1: that they're they're they're nauseous or something. I don't know, Um,
Speaker 1: they have they have some sort of illness, but you've
Speaker 1: got an inner ear problem. Gravity is normal. Yeah, As
Speaker 1: a Clement company point out in the article, quote, perhaps
Speaker 1: it is not necessary to perceive artificial gravity at the
Speaker 1: cognitive level for it to be effective as a countermeasure. However,
Speaker 1: for purposes of defining the comfort zone of astronauts and
Speaker 1: artificial gravity environments, whether it's a rotating spacecraft or an
Speaker 1: onboard centrifuge, it would be extremely useful to determine the
Speaker 1: threshold value of perceived artificial gravity. Unfortunately, there are no
Speaker 1: plans to put a human centrifuge on board the I
Speaker 1: S S, at least in the near term. So when
Speaker 1: it comes to G's um you know, Mars is point
Speaker 1: three seven six GS, Neptune is one point fourteen. G's
Speaker 1: Saturn is one point of seven GES. Guess they're not
Speaker 1: going to be standing on the surfaces of Neptune or
Speaker 1: but we have stood on the surface of the Moon,
Speaker 1: which is point one six Geese and Clement and Company
Speaker 1: point out that when astronauts visited the Moon, they had
Speaker 1: trouble figuring out which weight was up and down. They
Speaker 1: didn't they didn't perceive a four point five degree floor
Speaker 1: tilt in their landing unit during Apollo eleven. Yeah, can
Speaker 1: you imagine that, Like you're you're on a slope, but
Speaker 1: the gravity is so weak you can't you don't get
Speaker 1: that you're on a slope, like you can't feel it.
Speaker 1: And then when they're bouncing around out there on the
Speaker 1: lunar surface. Uh, there were a lot of stumbles, and
Speaker 1: a number of these stemmed from the inability to evaluate
Speaker 1: terrain slope. Yeah, again, like you can't tell the difference
Speaker 1: between uphill and downhill. It's hard to imagine. Yeah, and
Speaker 1: yet I mean the moon gravity is perfectly enough to
Speaker 1: keep you tethered to the surface of the Moon. You're
Speaker 1: not gonna fly away or anything, right, Yeah, You're not
Speaker 1: gonna leap up and achieve you know, escape velocity. Now,
Speaker 1: there is another study, and this is actually a proposed
Speaker 1: study currently, and this is the NASA funded turbo lift,
Speaker 1: the turbo lator. Yeah, and this, Uh. The idea here
Speaker 1: is to combat the effects of micro gravity by accelerating
Speaker 1: an astronaut literally had one G for what a round
Speaker 1: of one second, and then it's rotated uh degrees to
Speaker 1: prepare for one G deceleration. It's kind of like being
Speaker 1: shaken up in a cocktail shaker, uh, and only your
Speaker 1: legs always point in the direction of the shake it.
Speaker 1: It would, theoretically, according to the proposers here, uh, feel
Speaker 1: like bouncing on a trampoline. So this would be a suggestion,
Speaker 1: not for a habitable environment or from a for a spaceship,
Speaker 1: but maybe for essentially some kind of exercise machine. Is
Speaker 1: that what we're thinking? Yeah, that that's what That's what
Speaker 1: I'm getting from this is that said quote. The intermittent
Speaker 1: loading is intended to reduce or eliminate the physiological deconditioning
Speaker 1: in a comprehensive multisystem manner. It would be it would
Speaker 1: be a situation where like, hey, Joe, I know you've
Speaker 1: got stuff to do on the spaceship, but it's time
Speaker 1: for your your one G treatment. You need to climb
Speaker 1: in the capsule here, and we're gonna you back and
Speaker 1: forth for however long you're treatment last. The flipping bullet. Yeah, Now,
Speaker 1: this does indicate that there are these two very different
Speaker 1: schools of thought about what to do when generating artificial gravity.
Speaker 1: I guess we sort of alluded to this a minute ago,
Speaker 1: but you still should keep in mind this question of
Speaker 1: what is the goal. Is the goal just to have
Speaker 1: an environment you can go into often enough to offset
Speaker 1: some of the negative health effects of being in space.
Speaker 1: Is it just sort of like tiny jim for your
Speaker 1: body to stay healthy, or are you actually trying to
Speaker 1: create an environment where some of the effects of Earth
Speaker 1: gravity are simulated for normal living purposes, so you can
Speaker 1: salt your food, so you can go to the bathroom
Speaker 1: without pooping into a vacuum cleaner. Now, I do have
Speaker 1: to say that, um, I can't help but think that
Speaker 1: this the jumper scenario, this turbo lift scenario. I could
Speaker 1: see it working if you had somebody in a hibernation
Speaker 1: state or some sort of suspended animation, like maybe you
Speaker 1: load their their corpsicle to one of these and shoot
Speaker 1: them back and forth to to keep their need to
Speaker 1: avoid any debilitating effects involved with their space travel. But
Speaker 1: of course for that to work, you have to have
Speaker 1: some sort of hibernation um a technique worked out, and
Speaker 1: that's a whole that's a whole another podcast topic. Now,
Speaker 1: in terms of complications with this linear model here of
Speaker 1: artificial gravity, you of course you have to be in
Speaker 1: motion there. You have to be able to produce that effect. Uh,
Speaker 1: you have to always be on your way somewhere or
Speaker 1: taking a roundabout way to continue the effect. But I'm
Speaker 1: not sure if that's such a detriment, because after all,
Speaker 1: space is big. The distance between planets, that's certainly between
Speaker 1: stars is vast, and there's plenty of room to to
Speaker 1: run around out there. Well yeah, I mean if you
Speaker 1: actually want to travel to say, another star system, and
Speaker 1: not just say to Mars, but if you want to
Speaker 1: go to Alpha Centauri or wherever. I mean, as much
Speaker 1: acceleration as possible is good. Uh, it's still I guess
Speaker 1: I have the question of about what the propulsion idea is, Like,
Speaker 1: how do you constantly generate that much acceleration? Exactly? Yeah,
Speaker 1: I guess with some models you have these ideas of like,
Speaker 1: you know, kind of like beamed propulsion back from Earth
Speaker 1: where you line you know, you like you line up
Speaker 1: this payload delivery of energy. Um, that's right. That's what
Speaker 1: we have in the Blindside, the novel that you just
Speaker 1: finished reading and I'm currently reading. Yeah. I mean, the
Speaker 1: whole thing about this is this seems like a method
Speaker 1: that would work and would be very interesting. Um, but
Speaker 1: I guess it's just waiting on some kind of abundance
Speaker 1: of energy and propulsion technology and the than the means
Speaker 1: to use it or the opportunity to use it. All Right, Well,
Speaker 1: that's linear acceleration for you. That's one model. We're going
Speaker 1: to take another break, and when we come back, we're
Speaker 1: going to dive into the much more popular artificial gravity scheme,
Speaker 1: the one that you see in the movies, And then
Speaker 1: of course is the spinning habitats, the Taurus, the standard
Speaker 1: tow us, the double Taurus. All these different models were
Speaker 1: of course talking about uh, the manipulation of centripetal force.
Speaker 1: Than all right, we're back. So, Robert, you've seen two
Speaker 1: thousand one of Space Odyssey. Oh yeah, one of my favorites.
Speaker 1: And so if you've seen that movie, you've seen at
Speaker 1: least a couple of different versions of the design for
Speaker 1: artificial gravity that exploits centripetal force or centrifugal force. I'll
Speaker 1: talk about the difference between them in a minute now.
Speaker 1: One example in the movie is this giant space station
Speaker 1: called space Station five V for five, and it's shaped
Speaker 1: like a wagon wheel. And the other is this round module.
Speaker 1: It's a spherical module within the spaceship that how controls
Speaker 1: in the movie, the spaceship the Discovery one, which is
Speaker 1: the one that's on the way to I think it's
Speaker 1: Jupiter in the movie and Saturn in the book, Is
Speaker 1: that right, I believe? So yeah, this is the one
Speaker 1: that's like really round in the front and long in
Speaker 1: the back, right, and so uh, in this crew module
Speaker 1: in the Discovery one in the movie, you see a
Speaker 1: gravity like effect pulling passengers to the floor along the
Speaker 1: equator of this compartment. So we can see the effect
Speaker 1: in this one scene where Frank Pool the astronaut is
Speaker 1: jogging in full circles around the inside wall of the sphere,
Speaker 1: So he's jogging laps, but he's not jogging horizontal laps.
Speaker 1: He's jogging full circular orbital laps. Yeah, i'd say it's
Speaker 1: one of it's it's one of you. Not like the
Speaker 1: greatest sequence in a science fiction film. It's just so
Speaker 1: beautiful and and and and and thought provoking. So there
Speaker 1: are multiple ways that you could set something like this up,
Speaker 1: and I'll explore a few of those models in a minute.
Speaker 1: But the basic idea is that you create a spinning
Speaker 1: structure within your spacecraft, and the outside edge of the
Speaker 1: spinning environment becomes a floor that pushes up against your
Speaker 1: feet the same way the ground pushes up against your
Speaker 1: feet as you are attracted steadily towards the center of
Speaker 1: the Earth. So, in other words, it simulates the effect
Speaker 1: of gravity. Now, like linear acceleration that we just talked about,
Speaker 1: rotation based gravity also relies on the pseudo force sensation
Speaker 1: generated by inertia to simulate gravity. It's your body's inertia
Speaker 1: feeling like the gravitational force that pulls you towards the
Speaker 1: center of the Earth. Now, in the case of the
Speaker 1: spinning model, this is known as centrifugal force or the
Speaker 1: centrifugal pseudo force. Now there are two terms that are
Speaker 1: easy to get confused here, centripetal force and centrifugal force. Uh.
Speaker 1: Centripetal forces is the real force in physics, and this
Speaker 1: is really there two sides of the same coin. So
Speaker 1: centripetal force is something that you will notice if you've
Speaker 1: ever done the old experiment. You know, the thing you
Speaker 1: do when you're a kid, is you get a bucket
Speaker 1: of water and you spin it around in a vertical
Speaker 1: circle so that the top of the circle your buckets
Speaker 1: upside down, but the water stays in the bucket, doesn't
Speaker 1: fall out like it would if you just hell the
Speaker 1: bucket upside down, and you you realize intuitively something's going
Speaker 1: on there about the force of your swinging motion with
Speaker 1: your arm. For some reason, it being at the top
Speaker 1: of a circular motion keeps the water in the bucket
Speaker 1: in a way that just turning the bucket upside down
Speaker 1: in the same place wouldn't. And so what that is
Speaker 1: is the centripetal force of the bucket pushing down on
Speaker 1: the water to hold it in while the inertia of
Speaker 1: the water flying in this circular motion wants it to
Speaker 1: fly off in a tangential pattern, uh, and a tangent
Speaker 1: going straight out from the path it's flying along. So
Speaker 1: you can think about it sort of like anytime something
Speaker 1: is is flying around in a circular motion, say a
Speaker 1: space station is orbiting the Earth, what it really wants
Speaker 1: to do is keep traveling in a straight line forever. Right,
Speaker 1: So if you've got the I s s it's orbiting
Speaker 1: the Earth, what what it wants to do if there
Speaker 1: were suddenly no Earth is just travel straight ahead, so
Speaker 1: it just key going off into space. But what the
Speaker 1: Earth does is it exerts a certain amount of force,
Speaker 1: pulling that the space station down towards its center of
Speaker 1: gravity and curving its path. And the same thing happens
Speaker 1: when you've got an object swinging in a circular path
Speaker 1: but contained by some kind of physical structure or force
Speaker 1: like your arm and the bucket holding the water in place. Now, so,
Speaker 1: so the centripetal force is the inward force that pulls
Speaker 1: everything toward the center of motion in a circular pattern.
Speaker 1: The centrifugal force sometimes referred to as a pseudo force
Speaker 1: because it's really just inertia in a moving reference frame.
Speaker 1: That's the apparent force that acts on an object moving
Speaker 1: in a circular path to push it outward from the
Speaker 1: center around which it rotates. And this would be taking
Speaker 1: the place of the gravity that actually pulls your feet
Speaker 1: towards the ground on Earth. Now you can also feel
Speaker 1: the intuitive physics of this on your body, just in
Speaker 1: your imagination. If you've ever done the carnival ride where
Speaker 1: you get on the what is it the cyclotron, the
Speaker 1: circula gravitron, it's the thing where they put you in
Speaker 1: a cage and your back is against the wall, and
Speaker 1: it's this big disc where everybody's back is against the
Speaker 1: inside wall of the disk, and then it starts spinning
Speaker 1: you around very fast, and suddenly you're just pinned to
Speaker 1: the back wall. You can't lift your arms up. Uh,
Speaker 1: And it's it's all this force that's that wants to
Speaker 1: throw you off into space, but in fact there's a
Speaker 1: wall they're stopping you, so instead of being thrown off
Speaker 1: into space, you're just pinned to the wall. Yeah, that's
Speaker 1: a carnival death machine that I've probably only written once,
Speaker 1: but but I have written a similar device and that
Speaker 1: is of course the like the pirate swinging ship. You know, okay,
Speaker 1: it has a similar similar effect as the bucket scenario
Speaker 1: if the pirates swinging ship or to go all the
Speaker 1: way around, not the on I ride. But oh interesting,
Speaker 1: uh well it's also yeah, this the centripetal centrifical force.
Speaker 1: It's the same thing also that allows you in a
Speaker 1: roller coaster to go around a loop. Roller coasters that
Speaker 1: have loops because the force that's keeping you, you know,
Speaker 1: you want your body wants to continue on a straight
Speaker 1: line as it gets to the top of the loop
Speaker 1: and just be flung off up into the sky. But
Speaker 1: instead you've got that roller coaster. They're holding you, so
Speaker 1: instead you're pressed down into your seat, which is actually
Speaker 1: straight up from the ground. Um. And so the same
Speaker 1: thing you can imagine could happen in space. If you've
Speaker 1: got a space environment and you're on a thing that's spinning,
Speaker 1: you know that you will experience some kind of force
Speaker 1: pinning you to the outside wall of that spinning structure
Speaker 1: in the same way as as the bucket of water
Speaker 1: and the loop to loop on the roller coaster. So
Speaker 1: then the question is how do you generate the right
Speaker 1: amount of force there. Obviously, you don't want your the
Speaker 1: inside of your space station to be like the gravitron
Speaker 1: ride where you can't even lift your arm and you're
Speaker 1: just pinned to the floor. Uh, you want to simulates
Speaker 1: something within the realm of one g or one of
Speaker 1: these fractions of one g that seemed like they might
Speaker 1: be a tolerable living environment or at least help offset
Speaker 1: some of the effects of micro gravity. And so you
Speaker 1: calculate how much force you generate towards the floor of
Speaker 1: a spinning structure by multiplying the radius of the structure
Speaker 1: by the speed of the rotation squared. So your two
Speaker 1: main variables are going to be how fast is the
Speaker 1: thing spinning around and how big is it? And since
Speaker 1: you're multiplying these together, the bigger the structure is and
Speaker 1: the faster it rotates, the more force there is towards
Speaker 1: the floor. And unlike the problem I just mentioned about
Speaker 1: being pinned to the floor, actually mostly the problem that
Speaker 1: we're going to experience is how to generate enough force,
Speaker 1: not how not to generate too much. Alright, so we
Speaker 1: have the basic principle here. We've already mentioned some of
Speaker 1: the sci fi scenarios. But what are some specific proposals. Well,
Speaker 1: you've got some basic shapes that you could think about,
Speaker 1: and then I'll talk about how those shapes have been
Speaker 1: proposed in the history. Now, one thing you could obviously
Speaker 1: look at is something like the two thousand one space station,
Speaker 1: which is like a wheel. So you'd have a donut,
Speaker 1: and inside the doughnut it's hollow, and people are walking
Speaker 1: around on the outer wall of the inside of the
Speaker 1: hollow donut. This would be the taurus shape or the
Speaker 1: wheel shape. And we tend to gravitate towards this because
Speaker 1: everyone loves the wheel, like the wheel is such a
Speaker 1: such an excellent human symbol. There, of course we want
Speaker 1: to see it in space, uh, you know, magnifying our
Speaker 1: glory as a species. Yeah, well there's that. There's there's
Speaker 1: the flying saucer. You know, we love to see a
Speaker 1: wheel that way. There's the passage in Ezekiel about seeling wheels,
Speaker 1: wheels and wheels. Now, there's also sort of the cylinder
Speaker 1: model right where you you'd have the same effect where
Speaker 1: you'd be moving on the outs or the inner wall
Speaker 1: or sorry, now here you'd have a similar effect where
Speaker 1: you'd be walking along on the inside of the outer
Speaker 1: wall of a spinning cylinder, and that would be a
Speaker 1: lot like the effects caused by the wheel. Another thing
Speaker 1: that's kind of interesting is the idea of something like
Speaker 1: a bolus or a or a tethered counterweight, where instead
Speaker 1: just imagine putting yourself in a box and then tying
Speaker 1: that box via a rope to an equally weighted counterweight
Speaker 1: out in space, and then you just set the two
Speaker 1: of you rotating against one another. This would also generate
Speaker 1: a force toward the outer floor of the box. The
Speaker 1: you know, the wall facing away from the rope would
Speaker 1: become the floor. Okay, it's less elegant. And the other
Speaker 1: thing about it is that it is called a bolus,
Speaker 1: which brings to mind various things flying out of either orifice. Right,
Speaker 1: So you're saying, like, if you had to perform the
Speaker 1: Heimlich maneuver on a fellow astronaut, they might cough up
Speaker 1: a bolus of food they've been choking on while you're
Speaker 1: in the bullus. Yeah, and then of course that all
Speaker 1: so read. Uh. I think I've read in like space
Speaker 1: manuals about uh using the toilet in space, they refer
Speaker 1: to the fecal bolus really, So the less you have
Speaker 1: to think about the fecal bolus or the traditional you know,
Speaker 1: bolus of food that you're your your your tongue helps
Speaker 1: form before you swallow. Yeah, you don't want to think
Speaker 1: about that when you're spinning around in a capsule in space.
Speaker 1: No you don't, Robert, No, you don't at all. Okay,
Speaker 1: So let's look at some specific examples of proposals for
Speaker 1: for spinning artificial gravity stations in spacecraft throughout the years.
Speaker 1: And here I'm gonna cite a lot from a specific
Speaker 1: chapter from that same book you mentioned earlier about artificial gravity.
Speaker 1: This would be the chapter on the history of artificial gravity,
Speaker 1: and that's again in that book by U by Clement
Speaker 1: Bookley and Pulaski. So one of the earliest known designs
Speaker 1: for a space station with artificial gravity created by rotation
Speaker 1: comes from the Russian physicist Constantin L. Tilkowski, who lived
Speaker 1: from eighteen fifty seven and nineteen thirty five. And Tiolkowsky
Speaker 1: was an interesting dude. He was one of the pioneers
Speaker 1: of rocketry theory, but he also was one of those futurists, right.
Speaker 1: He was one of these people who became obsessed with
Speaker 1: the idea of colonizing space. He wanted humans to colonize space.
Speaker 1: He wanted Earth domination of the galactic neighborhood. And one
Speaker 1: interesting story I found is that he at one point
Speaker 1: built a big centrifuge to test out the effects of
Speaker 1: acceleration or artificial gravity on the human body. But he
Speaker 1: didn't use human test subjects. He tested it on chickens
Speaker 1: and made the gravity chickens rest in peace anyway. In
Speaker 1: his manuscript, the title of which translates to free Space
Speaker 1: in eighteen eighty three, Tiolkowsky sketched a hypothetical spacecraft and
Speaker 1: designed how you could spin a spaceship to give it
Speaker 1: artificial gravity on the outward facing walls. Another pioneer who
Speaker 1: would be Sergey Kralv, one of the great minds behind
Speaker 1: the Soviet space program. He was a really vicious guy,
Speaker 1: and in nineteen fifty nine he was designing a trip
Speaker 1: to Mars in nineteen fifty nine via a spacecraft called
Speaker 1: the Heavy Interplanetary Manned Vehicle. And no, this was nineteen
Speaker 1: fifty nine. This was before Uri Gagarin's first spaceflight in
Speaker 1: nineteen sixty one. No human had been to space at
Speaker 1: this point, and this guy's like, all right, we gotta
Speaker 1: get this Mars trip on the road. Um. And anyway,
Speaker 1: this uh, this spaceship that he was designing, the h
Speaker 1: I m V. It would have a mass of seventy
Speaker 1: five tons, a length of twelve meters, and it would
Speaker 1: have this cabin that was six meters in diameter. That's
Speaker 1: not a whole lot, but he he did imagine that
Speaker 1: he would be able to use this ship as a
Speaker 1: rotating artificial gravity environment. UM. We can talk later about
Speaker 1: exactly how feasible very small rotating artificial gravity environments are.
Speaker 1: The short answer is not very um. So coral Lev's
Speaker 1: during were severely limited by material and political constraints, and
Speaker 1: during the nineteen sixties he was forced to focus more
Speaker 1: on attempting to sort of match Apollo scale space projects UH,
Speaker 1: and to work on weapons programs of course, and so
Speaker 1: he also ended up proposing a tethered capsule based artificial
Speaker 1: gravity experiment, but it was never carried out and coral
Speaker 1: Lev died in nineteen sixty six and the project was
Speaker 1: shut down. But I mentioned this, this tethered system, the bolus. Right,
Speaker 1: you have two things attached by a tether and you
Speaker 1: rotate them against one another to see if you can
Speaker 1: generate a force. That kind of system was actually tried
Speaker 1: in space by the Americans. Now, if you'd asked me
Speaker 1: a few weeks ago, I think I would have thought
Speaker 1: that that nobody had ever carried out large scale artificial
Speaker 1: gravity experiments on or at least on the human scale
Speaker 1: in space. I know they you know, they've centrifuged a
Speaker 1: few small animals and little contraptions, But I did not
Speaker 1: know there had ever been anything on the human scale.
Speaker 1: This experiment may count though it's it's a pretty weak attempt,
Speaker 1: but it was an attempt. I don't mean to say
Speaker 1: week like these astronauts and scientists didn't know what they
Speaker 1: were doing, but they didn't attempt all that much in
Speaker 1: terms of artificial gravity, right, I mean, it has will
Speaker 1: become clear as you explain it. It's still like anything
Speaker 1: you do in orbit is pretty balls. Yeah. So so
Speaker 1: this this definitely qualifies. But to your point in might
Speaker 1: it's not exactly a robust exploration. Yeah. So this this
Speaker 1: is the Bullus method, and it was tested to a
Speaker 1: to a very small extent during the Gemini eleven mission
Speaker 1: in nineteen sixty six. Or as the people at the
Speaker 1: time would say, Jiminy. And it was crewed by Charles
Speaker 1: Pete Conrad and Richard Gordon. And while in orbit around
Speaker 1: the Earth, the Gemini spacecraft was attached to a heavy
Speaker 1: counterweight object called the Agena Target Vehicle by h and
Speaker 1: that Agena Target vehicle had on it a thirty meter tether. Now,
Speaker 1: at the time, we didn't have these really good complicated
Speaker 1: botic arms or auto locking cable jack's. To get these
Speaker 1: two objects connected via the tether, Richard Gordon, the crew member,
Speaker 1: had to leave the cabin in a space suit and
Speaker 1: attach the tether manually. And apparently this job was grueling.
Speaker 1: Gordon got so overexerted doing it that his life support
Speaker 1: system was stressed and he was sweating so much inside
Speaker 1: his space suit that he couldn't see out of his
Speaker 1: right eye. Oh man, because I imagine it's just kind
Speaker 1: of like pulling up, puddling up right, exactly like the
Speaker 1: dripping off frozen in the lake at the bottom of
Speaker 1: Dante's Inferno, you know. Oh oh man, yeah, wow, I
Speaker 1: never thought about I had really not thought about the
Speaker 1: like the sweating in space and blinding yourself with your
Speaker 1: own tears horrible, but anyway, yes, sweating so much he
Speaker 1: blinded himself in his right eye. Anyway, he did manage
Speaker 1: to get the two spacecraft attached by the tether. He
Speaker 1: got back inside the Gemini cabin and they were able
Speaker 1: to close the hatch and repressurize. Later, or after they
Speaker 1: were connected via the tether, the two spacecraft undocked from
Speaker 1: one another, so they disconnected except for the tether. And
Speaker 1: then they stretched out and pulled the tether taut and
Speaker 1: they began a rotation movement. And apparently it was hard
Speaker 1: to get this stable because they were what they called oscillations.
Speaker 1: I imagine that's like the tether being taught but then
Speaker 1: loosening maybe or moving side to side. Um, there were
Speaker 1: oscillations in the rotation and for the first twenty minutes
Speaker 1: or so, and then after that the rotation rate was
Speaker 1: was increased and the crew successfully managed to generate a
Speaker 1: tiny artificial gravity effect inside the Gemini eleven capsule. UH Supposedly,
Speaker 1: one way they measured this is somebody dropped a camera
Speaker 1: and it went in a straight line toward the floor,
Speaker 1: toward the outside wall of the capsule that was away
Speaker 1: from where the tether was so they measured it and
Speaker 1: figured that they had generated about zero point zero zero
Speaker 1: zero five G. And but that was with row point
Speaker 1: fifteen revolutions per minute. So this is a very slow rotation.
Speaker 1: It's not a huge construct. Um So, I mean, that's
Speaker 1: a reasonable thing to generate. If they had been rotating faster,
Speaker 1: or if the tether had been longer, they might have
Speaker 1: been able to to to create a more powerful effect.
Speaker 1: But anyway, this did prove the principle. And afterwards the
Speaker 1: tether was released and the edge in a vehicle was
Speaker 1: dropped to its orbital fate after about three hours. Now
Speaker 1: moving on, the author's also talk about how in nineteen
Speaker 1: eight there was this Slovene engineer named Herman Potasnik, writing
Speaker 1: under the pseudonym Herman nor Dung, who proposed a wheel
Speaker 1: shaped space station with habitation around the rim of the wheel.
Speaker 1: And his idea was that you'd have this wheel that
Speaker 1: people would live in, and then the hub of the
Speaker 1: wheel you'd have a power generating station and this would
Speaker 1: have been thirty meters in diameter. It was called the
Speaker 1: one rod or living wheel. And then in nineteen fifty
Speaker 1: three in Collier's Weekly, the German American rocket scientists Werner
Speaker 1: von Braun took this wheel shaped model and updated it
Speaker 1: to be larger with a seventy six meter diameter, and
Speaker 1: von Braun calculated that if you had a wheel seventy
Speaker 1: six ms wide and it rotated at three revolutions per minute,
Speaker 1: you could simulate a gravity of zero point three G,
Speaker 1: which is sort of close to the gravity of Mars,
Speaker 1: which is zero point three h G. And this would
Speaker 1: make it supposedly a good training facility from Mars expeditions,
Speaker 1: but also, as we were talking about earlier, might be
Speaker 1: within livable tolerances for human life. You know, if if
Speaker 1: that's the best you could do in space, that might
Speaker 1: still be better than micro gravity, better than nothing at all, right,
Speaker 1: I mean, without without like actually doing any math on this,
Speaker 1: if you could make it to wear really rigorous exercise
Speaker 1: regime for your space faring human if it allowed them
Speaker 1: to like to cleanly break even against you know, loss
Speaker 1: to to bone in muscle, then it would be worth it, right, right,
Speaker 1: I mean, I'd imagine three hours of exercise a day
Speaker 1: and zero point three G does a lot more work
Speaker 1: than three hours of exercise a day and zero G. Yeah,
Speaker 1: And on top of that you're getting acclimatized to the
Speaker 1: gravity that you're headed towards. Totally. Yeah, and so there
Speaker 1: have also been some really interesting proposed odd models, Like
Speaker 1: in nineteen sixty four Dandridge Coal and Donald Cox proposed
Speaker 1: this interesting idea. So Coal was really interested in the
Speaker 1: mining and colonization of asteroids, and one of his proposed
Speaker 1: ideas was that you'd capture a large asteroid to be
Speaker 1: about thirty kilometers in length, that ideally be an elliptical asteroid,
Speaker 1: kind of egg shaped, and you'd hollow out the inside
Speaker 1: of it, and then you would use propulsion to get
Speaker 1: the asteroid rotating along its major axis, and this would
Speaker 1: generate artificial gravity inside the hollowed out asteroid, and you
Speaker 1: could sort of build a bubble city on the inside
Speaker 1: walls of the hollow space rocks, sustained by shining sunlight
Speaker 1: into the core with rors. This was also explored on
Speaker 1: the Expanse by the way they talk about colon cox Um.
Speaker 1: I don't remember if they if they actually referenced them
Speaker 1: in any way, but there's they discussed like the the
Speaker 1: early efforts to reach these various asteroids and to create
Speaker 1: a spin mine amount get them spinning and then you
Speaker 1: can build habitats inside them. Did it work or not work?
Speaker 1: I mean in the in the knovel The Toll it worked. Yeah, okay, yeah.
Speaker 1: The only thing that didn't work in the novels was
Speaker 1: the colonization of Venus, like that ended up failing. They're
Speaker 1: trying to create like floating cities. Yeah, but anyway, elm,
Speaker 1: that could go really bad. Well anyway, so yeah, another
Speaker 1: weird idea this, well, it's actually maybe not that weird
Speaker 1: because here you get something like it. In two thousand
Speaker 1: one of Space Odyssey would be a sphere. Yeah, so
Speaker 1: the American physicist Gerard K. O'Neill proposed a rotating sphere
Speaker 1: that he called Island one. And this would be five
Speaker 1: in diameter, rotate once every thirty second, which he said
Speaker 1: would generate about one earth g at the equator. Now
Speaker 1: that's an important thing to consider, a rotating sphere. It
Speaker 1: would be different than a rotating wheel, and that there'd
Speaker 1: be areas you could access that would not have the
Speaker 1: same gravity. Right, Like, if if you go to the equator,
Speaker 1: you'd get your maximum gravity. But then if you walk
Speaker 1: up to the poles of the rotating sphere, you'd basically
Speaker 1: be waitless because it wouldn't be a like a hollow
Speaker 1: Earth scenario where you would ideally have like the mass
Speaker 1: of the crust. Like a mass is not going to
Speaker 1: play a part in this, So yeah, you would. You
Speaker 1: would only experience the the maximum GS at that equator
Speaker 1: because again it's not actually due to gravity, is due
Speaker 1: to acceleration, right, It's due to your inertia against the
Speaker 1: constant angular acceleration of the rotating reference frame. Later that
Speaker 1: same guy, Gerard O'Neill, he proposed a larger model he
Speaker 1: called Island two and eventually this gigantic aluminum structure that
Speaker 1: came to be known as the O'Neill cylinder. And this
Speaker 1: would end up measuring more than thirty kilometers long and
Speaker 1: three point two kilometers in radius. And you do this
Speaker 1: by rotating a little over once every two minutes, which
Speaker 1: could create earth gravity around the inside edges of the cylinder.
Speaker 1: And he envisioned this model would actually it would be
Speaker 1: like an Earth in space. It would contain natural landscapes
Speaker 1: that have forests and rivers and individual villages within. Yeah,
Speaker 1: you'd have sunlight directed inside from external mirrors. I mean,
Speaker 1: crazy stuff that there's a he had a book book,
Speaker 1: The High Frontier Human Colonies in Space, and the illustrations
Speaker 1: from this are just magnificent. I know you included one
Speaker 1: in in our notes for this this episode, not trying
Speaker 1: to include some on the landing page for this episode
Speaker 1: of Stuff to Blow your Mind dot com. Because these
Speaker 1: are just gorgeous, gorgeous sci fi illustrations that really capture
Speaker 1: that sort of retro optimism for humanity's future beyond Earth.
Speaker 1: Why did they kind of make me think of like
Speaker 1: Broigel or something. Yeah, yeah, I mean it's it's it's
Speaker 1: these just landscapes, you know, turned on their side and
Speaker 1: looped together to create this uh this this this internal
Speaker 1: rotating world. Yeah, I'm not quite sure why, but this
Speaker 1: one illustration we've got included here, it reminds me of
Speaker 1: uh Brogel's landscape with the Fall of Icarus. Though I
Speaker 1: don't think you're you're allowed to invoke Icarus when contemplating
Speaker 1: such titanic feats of human achievement, and with so many
Speaker 1: lives at stake, it is a temptation of the gods
Speaker 1: to call down uh misfortune on our Hubris, and I
Speaker 1: mentioned the lives involved because, for instance, in in In
Speaker 1: O'Neill's Island one. Here he's talking about tens of thousands
Speaker 1: of people living inside there and uh you know, a
Speaker 1: living there out their planet free lives and a technological
Speaker 1: uh semilacrum of their home world environment. Anyway, you will
Speaker 1: have to to look at the images. That truly beautiful stuff,
Speaker 1: totally and you can see in the images that like
Speaker 1: the idea for the hollow asteroid, this would use huge
Speaker 1: windows and mirrors to shine sunlight inside for night and
Speaker 1: day cycles, which would be another thing that would be
Speaker 1: absolutely crucial if you're trying to fully simulate an Earth environment. Now,
Speaker 1: I guess it's finally time to talk about probably the
Speaker 1: favorite model, the thing that everybody usually goes to, which
Speaker 1: is the Taurus. It's the standard, Yes, it is the standard,
Speaker 1: and it is the standard from Stanford, the Stanford Taurus.
Speaker 1: So this is really the answer to what's most feasible,
Speaker 1: or at least what scientists have concluded in the past.
Speaker 1: So in ve NASA and the American Society for Engineering
Speaker 1: Education put together a study comparing submitted designs for spacecraft habitats,
Speaker 1: and this was published by Johnson and Holbrow in nine
Speaker 1: and it looked at wheel shaped design, cylinder design, spherical designs,
Speaker 1: and NASA ultimately decided that a design submitted by stand
Speaker 1: Ford students was the most feasible, and this was the
Speaker 1: design that came to be known as the Stanford Taurus.
Speaker 1: So it taurus is like we've been saying, a ring,
Speaker 1: it's a hollow doughnut, and the Stanford Taurus would be
Speaker 1: a ring shaped tube. So it's a tube like a cylinder,
Speaker 1: except it's a tube that goes around in a circle
Speaker 1: and connects on itself a hollow donut. And so inside
Speaker 1: that tube it would be a hundred and thirty meters across.
Speaker 1: Now keep in mind that's not the diameter of the
Speaker 1: whole ring that's inside the tube that makes the ring,
Speaker 1: but the diameter of the whole thing would be about
Speaker 1: one point eight kilometers across, and then it would be
Speaker 1: the tube would be about five point six kilometers long.
Speaker 1: So that would be the circumference and spinning the ring
Speaker 1: at one revolution per minute at these dimensions, it would
Speaker 1: generate about one G along the outer edge of the
Speaker 1: tube or earth gravity, and so feasibly you could build
Speaker 1: whole earth environments inside, like the O'Neill cylinder. If this
Speaker 1: were built, you could supposedly have running wall or farms, woods,
Speaker 1: all that kind of stuff to make a space habitat
Speaker 1: as lovely and wonderful as our natural Earth habitat. And
Speaker 1: in the nineteen sixties and seventies, NASA did investigate ideas
Speaker 1: for creating artificial gravity environments for upcoming space missions. There's
Speaker 1: one illustration I found that I thought was pretty cool.
Speaker 1: I I don't know what the name of this is.
Speaker 1: I don't know if it had a name. I'm calling
Speaker 1: it the Rod because it's also a rotating space station,
Speaker 1: but it's just a big rod. Now it's not rotating.
Speaker 1: It's not rotating, you know, like rolling as a rod.
Speaker 1: It's spinning, spinning baton, which I thought was interesting. So
Speaker 1: in nineteen sixty nine, the U. S. Space Agency concept
Speaker 1: drawing for for this space station was produced. And I
Speaker 1: think it's an interesting concept. But obviously it has you know,
Speaker 1: so it's got less material investment than the construction of
Speaker 1: a huge wheel. But I would imagine it also has drawbacks,
Speaker 1: like the farther you farther along you are towards the
Speaker 1: ends of the raw odd, the more gravity you experience, right,
Speaker 1: because gravity is a product of the speed of the
Speaker 1: rotation and the radius, and so as you go toward
Speaker 1: the center of the rod, you're shortening your radius, and
Speaker 1: as you go towards the outside of the rod, you're
Speaker 1: lengthening your radius, and so at the center you'd be waitless.
Speaker 1: So I can imagine maybe something like this would be
Speaker 1: a system where the end compartments are again the places
Speaker 1: you go for your daily workouts in earth gravity, ha, Yeah,
Speaker 1: to keep your your muscles and bones strong. And then
Speaker 1: the lower gravity environments would be I guess we'd do
Speaker 1: other things. Maybe you'd sleep there, you know, I don't know,
Speaker 1: store stuff there or something like that. Or it's just
Speaker 1: where the captain gets to live, you know. Everyone else
Speaker 1: has to float and deal with it. Yeah, And and
Speaker 1: this does draw on conceptually something that we see in
Speaker 1: science fiction a lot of the time, which is that
Speaker 1: maybe not the entire habitable portion of the of a
Speaker 1: spacecraft has artificial gravity. Maybe much of it is going
Speaker 1: to be a micro gravity environment where your flow around,
Speaker 1: but there's like one room that's a rotating drum or
Speaker 1: taurists or something that you can go into and there's
Speaker 1: artificial gravity, and that one contained environment yeah. Now in
Speaker 1: in Peter Watt's blind side, Yes, if I remember correctly,
Speaker 1: here there are portions of the ship that have artificial
Speaker 1: gravity DA spin, Yes, but they're also working and even
Speaker 1: sleeping in the zero gravity are I think so? Yeah?
Speaker 1: I think so. I think most of the ship, if
Speaker 1: I recall, is going to be a zero gy environment
Speaker 1: where you're floating around you have to propel yourself. And
Speaker 1: then there's one portion of the ship known as the
Speaker 1: drum that's the gravity environment. So there have been a
Speaker 1: lot of these propositions over the years. You know, NASA
Speaker 1: has looked at how to create space stations like this,
Speaker 1: but ultimately these designs would be extremely expensive to produce
Speaker 1: and difficult to execute a little bit more on that later.
Speaker 1: But another factor is that, you know, NASA's scientists are
Speaker 1: looking at this and they're saying, well, a lot of
Speaker 1: the experiments we want to carry out or microgravity experiments anyway, Right,
Speaker 1: So I don't know, do do we really need to
Speaker 1: spend all this money making the International Space Station UH
Speaker 1: an artificial gravity environment when people are going to be
Speaker 1: spending their whole lives there, They're just gonna be there
Speaker 1: for a short period of time. And then they're gonna
Speaker 1: come back and they'll be able to recover some the
Speaker 1: negative health effects. Yeah. I mean there's two two of
Speaker 1: the main points wrapped up in that we don't really
Speaker 1: need um artificial gravity right now, not based on what
Speaker 1: we're currently doing. Yeah, and we're still there's still so
Speaker 1: much to learn about the effects of micro gravity on
Speaker 1: organisms right now. There's also still a lot to learn
Speaker 1: about the effects of artificial gravity on organisms. Now if
Speaker 1: that's with the qualification it's taught. What you're talking about
Speaker 1: there is the specific effects of centrifugal artificial gravity, because
Speaker 1: those are going to be somewhat different than just a pure, say,
Speaker 1: linear acceleration type artificial gravity that's going to be mostly
Speaker 1: indistinguishable from Earth UM in centrifugal environments, if you're in
Speaker 1: a spinning environment, depending on how small the radius is
Speaker 1: and how fast you're spinning, it could have weird effects.
Speaker 1: And I'll talk about those complications in a minute. But
Speaker 1: so to study those weird effects, scientists have conducted UH
Speaker 1: experiments on animals like fish, rats, turtles, and generally animals
Speaker 1: seem to survive centerfuging in space just fine, though in
Speaker 1: systems with a very high rotation rate. Rats seem to
Speaker 1: have a problem with orientation, movement, and vestibular and motor coordination,
Speaker 1: so it's not a big surprise. But if you put
Speaker 1: them in a rotating centerfuge with a small radius and
Speaker 1: very fast rotation, you get some very dizzy and confused
Speaker 1: and uncomfortable rats. But on the plus side, the centerfuging
Speaker 1: process does appear to stave off the wasting effects of
Speaker 1: zero G, so if you put animals in a centerfuge
Speaker 1: like this, their bones and muscles do appear to stay strong. Now,
Speaker 1: just to turn to one more recent proposity, ession of
Speaker 1: an artificial gravity spacecraft, h I thought we should look
Speaker 1: at real quick at the Nautilus X. Apparently this is
Speaker 1: also the name of some vaping product, which is most
Speaker 1: of what the Google results are about, so God help
Speaker 1: us there. But uh, the Nautilus X was a proposed
Speaker 1: NASA spacecraft that would contain a rotating centerfuge. It would
Speaker 1: have a TURUS ring that was built to simulate partial
Speaker 1: Earth G for the habitable quarters. And this spacecraft was
Speaker 1: designed but never built, And you can look up images
Speaker 1: of the design on the Internet. It's kind of interesting
Speaker 1: to see and I think the idea is that part
Speaker 1: of it here would have this hollow doughnut that would
Speaker 1: be rotating and you could you could transfer its momentum
Speaker 1: to a flywheel and uh and so it would be
Speaker 1: rotating around the ship and you could get in there
Speaker 1: to have some gravity time. And there have also been
Speaker 1: plenty of proposals over the years to add a centerfuge
Speaker 1: to the I S S in order to test artificial gravity.
Speaker 1: As far as I can tell, I don't think anything
Speaker 1: like that is still on the runway right now. I
Speaker 1: think these plans have pretty much stalled out. And I
Speaker 1: don't know if you were able to do across anything.
Speaker 1: But yeah, that was that seemed actually active right now. Yeah,
Speaker 1: but there may be hope. So I don't know, if
Speaker 1: you're out there working on a center fugure for the
Speaker 1: I S S and you think it might one day
Speaker 1: get up there, let us know. Well, you know, the
Speaker 1: Turbo lift that I mentioned, like that news of it
Speaker 1: being funded, that's just this year. So it's possible that
Speaker 1: there's some additional initiatives that have been funded in the
Speaker 1: past couple of months. I hope they're not in competition.
Speaker 1: Would it be Turbo later versus centerfuge. Oh, it sounds
Speaker 1: like a great battle. That's just sure. Now I've mentioned
Speaker 1: several times the possible complications of a spinning artificial gravity environment,
Speaker 1: right you can sort of imagine that there might be
Speaker 1: some that's spinning around in a circle towards the floor.
Speaker 1: Is not going to be exactly the same as having
Speaker 1: a gravitational force pulling you towards the ground. It it
Speaker 1: might in most cases, or depending on the radius and
Speaker 1: the rotation rate, be mostly indistinguishable, but especially it's smaller scales,
Speaker 1: there are gonna be some weird complications. This is gonna
Speaker 1: be the frozen from concentrate orange juice version of fresh
Speaker 1: orange juice. Yep, I think we should talk about the
Speaker 1: Coriolis force. So, Robert, imagine you're on a ferris wheel.
Speaker 1: You at home as well. Imagine you're up there. You're
Speaker 1: in the car on the ferris wheel, and you're just
Speaker 1: coming up over the top of the ferris wheel, and
Speaker 1: you notice that a friend of yours is directly below you,
Speaker 1: and you want to pour some mountain dew on their head,
Speaker 1: so you pour away. You pour the mountain dew to
Speaker 1: hit your friend, but you miss, and the dew instead
Speaker 1: hits the people in the car directly behind your friend.
Speaker 1: And this really shouldn't surprise anybody, right, this is just duh.
Speaker 1: I mean, you're on a ferris wheel. Even though your
Speaker 1: friend was directly below you when you began pouring the
Speaker 1: liquid straight straight down, the wheel was in motion, and
Speaker 1: by the time the liquid fell and reach the bottom,
Speaker 1: your friend had moved out of the way and somebody
Speaker 1: else had moved in. Now, this is totally normal, totally
Speaker 1: intuitive physics on a ferris wheel because we're generally looking
Speaker 1: at a ferris wheel from the outside. But if you
Speaker 1: try to imagine riding a rotating machine like a ferris
Speaker 1: wheel around in a circle in zero G in a
Speaker 1: closed environment, the rotation becomes your new stationary reference frame
Speaker 1: you the The whole idea is that you're supposed to
Speaker 1: be able to forget that you're rotating, and instead of
Speaker 1: feeling rotation, just feel a pull toward the floor. Like.
Speaker 1: Notice how even though your section of the Earth is
Speaker 1: orbiting the Sun and rotating around the Earth's axis, everything
Speaker 1: seems perfectly still. Right. This is your inertial reference frame,
Speaker 1: and since everything around you is moving, it roughly the
Speaker 1: same speed in the same direction, everything feels like it's
Speaker 1: holding still, And the same thing could happen inside a
Speaker 1: closed environment, rotating in a constant and speed in direction
Speaker 1: in space, and so then the exact same trajectory we
Speaker 1: saw with pouring the liquid down from the top to
Speaker 1: the bottom of the ferris wheel still applies, but because
Speaker 1: we're not looking in from the outside, it starts to
Speaker 1: look super odd. Like you could throw a packet of
Speaker 1: dehydrated space lasagna straight at somebody's face across the torus
Speaker 1: from or across the cylinder or whatever it is in
Speaker 1: this spaceship, and it would appear that even though you
Speaker 1: threw it straight, this thing you threw would suddenly arc
Speaker 1: over to the side, and so from your perspective, things
Speaker 1: would have this bizarre motion that wouldn't appear to make
Speaker 1: any sense at all unless you were looking at the
Speaker 1: ship from the outside. Yeah, and there's actually a point
Speaker 1: in Blindside where they referenced this where one individual throws
Speaker 1: it's either it's a ball or fruit or an apples.
Speaker 1: I think it's an apple, yeah, yeah, and uh and
Speaker 1: it kind of goes wide yeah yeah, yeah, And this
Speaker 1: would be a problem. Now that might not be a
Speaker 1: big deal because you're like, well, how often do you
Speaker 1: need to throw something to somebody? Well, actually, if you
Speaker 1: watch people in the International Space Station, they're sort of
Speaker 1: tossing stuff to each other a lot. Yeah, they're taking
Speaker 1: advantage of the microgravity. But it gets a lot worse
Speaker 1: than just tossing stuff to each other, because this also
Speaker 1: is going to affect just general movement. If you're at
Speaker 1: a small enough scale, like if your radius is small
Speaker 1: enough and your rotations are fast enough, this is going
Speaker 1: to be affecting how your body itself moves. And it
Speaker 1: gets even worse when you think about how it could affect,
Speaker 1: like affect your internal body systems. Yeah, I mean you
Speaker 1: could you could find yourself in your chamber and no
Speaker 1: matter how how else the rest of you feels about
Speaker 1: your your your artificial gravity scenario, you might feel a
Speaker 1: bit nauseous. The coreolis effects on inner ear into limp
Speaker 1: flow and on moving limbs creates a disorientation, nausea, vomiting,
Speaker 1: and even can cause loss of coordination. Yeah, and this
Speaker 1: actually isn't all that hard to understand because you've probably
Speaker 1: experienced something like this in your life. If you've ever
Speaker 1: been car sick while trying to read inside a moving car.
Speaker 1: In both cases, what's going on is that the fluids
Speaker 1: inside your body are slashing around in directions that don't
Speaker 1: make sense to your eyes based on your environmental reference frame.
Speaker 1: So in a car, you're sitting in the car, you
Speaker 1: don't really feel like you're moving. You just kind of
Speaker 1: feel like, Okay, I'm sitting here stationary in a car,
Speaker 1: especially if you're reading or doing something with your eyes down,
Speaker 1: you're not getting the information about movement around in your environment. Meanwhile,
Speaker 1: the inside of your body, especially your inner ears, saying
Speaker 1: like whoa, We're all over the place, what's going on?
Speaker 1: And that discus This discontinuity or disagreement between the movement
Speaker 1: information supplied by your senses and felt by your inner
Speaker 1: ear causes this destabilizing sensation. It makes you sick. Now.
Speaker 1: One of the issues here that we keep coming back
Speaker 1: to is that the smaller you're rotating environment, the more
Speaker 1: it is actually a carnival ride, and that the larger
Speaker 1: it is, uh, the better chance you have it's smoothing
Speaker 1: some of the more undesirable effects out exactly right. So
Speaker 1: if you I mean, one thing you'll notice is that
Speaker 1: like there are Coriolis effects in the rotation of the Earth, right,
Speaker 1: but normally come yeah, if you throw a baseball, if
Speaker 1: you are just standing around, like, the Coriolis effect of
Speaker 1: the rotation of the Earth is not messing with you
Speaker 1: too bad because the Earth is huge. Um, if you
Speaker 1: if you were in a much smaller rotating reference frame,
Speaker 1: it would be messing with you a lot more. I mean,
Speaker 1: mainly on Earth. You only see the rotation of the
Speaker 1: Earth causing Coreola's forces to affect a large scale movement
Speaker 1: such as like tides and weather patterns, you know, huge
Speaker 1: movements over long distances and long time. Yeah, and so
Speaker 1: the same would be generally true in an artificial gravity
Speaker 1: environment that was rotating, if it was a very very
Speaker 1: big radius and a slow rotation. In this environment, the
Speaker 1: Coriolis forces would be much less likely to have a
Speaker 1: noticeable effect on your body and on the stuff you're doing.
Speaker 1: Another side effect, especially of a small radius fast rotation
Speaker 1: end system, would be in a rotating environment, you could
Speaker 1: have unequal gravity loading. That's about as weird as it sounds.
Speaker 1: So the centrifugal force you feel like we were saying,
Speaker 1: is partially determined by your distance from the hub so
Speaker 1: in a big wheel, this isn't it's not gonna matter
Speaker 1: very much. You know, the percent distance from the hub
Speaker 1: between your head and your feet, if the hub is
Speaker 1: hundreds and hundreds of meters away, is just you know,
Speaker 1: it's just not that much. If it's ten meters away,
Speaker 1: then suddenly you might start to feel a significant difference
Speaker 1: between the gravity affecting your feet and the gravity affecting
Speaker 1: your head, and this could affect it could lead to
Speaker 1: problems with things like circulation. But it would also just
Speaker 1: be disorienting and make movement difficult, partially negating the benefits
Speaker 1: of artificial gravity. Another reason that if we were going
Speaker 1: to make one of these things and it was to
Speaker 1: be effective, it would need to be very big. And
Speaker 1: that is the answer to one of our final questions
Speaker 1: here at the end. You're saying, okay, so we know
Speaker 1: basically that we could make some for of artificial gravity
Speaker 1: sort of work. I mean, it might not be perfect,
Speaker 1: but this is you know, basic physics. This is not
Speaker 1: something that's totally hypothetical. It could work, So why haven't
Speaker 1: we done it? The main issue is size and cost
Speaker 1: for a spending artificial gravity environment to be tolerable to
Speaker 1: human occupants. It would need to be pretty big, and
Speaker 1: to be that big, you would need lots of construction materials.
Speaker 1: And to get lots of construction materials into space, you
Speaker 1: need lots of rocket launches. And rocket launches are very expensive.
Speaker 1: They're getting cheaper, but they're still very expensive for the
Speaker 1: tons of materials you need to get up there to
Speaker 1: build this stuff. So it really at this point is
Speaker 1: mainly a matter of cost, right, And I mean you
Speaker 1: can basically any any space mission, any space initiative. I mean,
Speaker 1: they're going to be priorities, and you can even if
Speaker 1: if something like this is on the list, it's going
Speaker 1: to get pushed down by other initiatives. Yeah, yeah, totally.
Speaker 1: And I mean, so building a one of these big,
Speaker 1: functioning artificial gravity environments that would be something habitable, generating
Speaker 1: something close to Earth g could fit a lot of
Speaker 1: people on it. You're you're probably talking about just a
Speaker 1: multi trillion dollar project here. It would just be so
Speaker 1: huge it's kind of not feasible for Earth space programs
Speaker 1: at the investment levels they're encountering. Now here's another problem.
Speaker 1: We've got some limits on research. Right. Ideally, if you're
Speaker 1: gonna launch one of these things in space, you'd want
Speaker 1: to do a lot of preparation research up front to
Speaker 1: make sure you're not making a big mistake about what
Speaker 1: what's the best thing to do in space. But on
Speaker 1: Earth there's really no feasible way to perfectly test out
Speaker 1: artificial gravity concepts because on the surface of the Earth
Speaker 1: you have to deal with the constant complications of Earth gravity.
Speaker 1: So you can kind of try to simulate weightlessness, and
Speaker 1: so you could do like neutral buoyancy experiments, you know,
Speaker 1: where you're in water with a sort of balanced out
Speaker 1: buoyancy weight ratio, or you could do you could get
Speaker 1: in an airplane and do parabolic flights to have you know,
Speaker 1: twenty five seconds at a time or so of weightlessness.
Speaker 1: But these things aren't all that helpful when you're talking
Speaker 1: about trying to test out an artificial gravity environment at
Speaker 1: a like ship or space station size scale, Yeah, you
Speaker 1: really need enough in zero G micro G environment, and
Speaker 1: to get that you have to go into space. You
Speaker 1: have to go to orbit, right, So to really test
Speaker 1: one of these things, you essentially have to do it.
Speaker 1: You can't really test it without just making this thing
Speaker 1: and putting it in space. Now, I guess the good
Speaker 1: news is that it's kind of to to to sort
Speaker 1: of reference the old Mitch Hedberg a bit about about
Speaker 1: an escalator. What do you call it? Broken escalator? It's stairs, right,
Speaker 1: Um is like if the thing didn't work, you just
Speaker 1: turn it off and you float. I guess right, Like,
Speaker 1: it's still going to be serviceable on some level. And
Speaker 1: you can imagine that. I can imagine a scenario. Maybe
Speaker 1: they've even done this in a sci fi where you
Speaker 1: have like a non functional tourists space station where people
Speaker 1: arriving like, hey, what's with the walls? How come? How
Speaker 1: come this thing didn't work? Well, it's it's it. We're
Speaker 1: working on it. We gotta work out the kinks, so
Speaker 1: it's not fully functional yet, right, yeah, yeah, And people
Speaker 1: could complain. They'd be like, oh, but I'm I'm experiencing
Speaker 1: space sickness. And you'd have to be like, hey, look,
Speaker 1: it's not as bad as the Coreoli's sickness, or it's
Speaker 1: a or it's a hotel. We have various rotating modules
Speaker 1: or rotating wings the hotel, and like, I'm sorry, all
Speaker 1: the all the rotating rooms are taken, all our gravity
Speaker 1: rooms are booked. Sorry, we've only got smoking rooms or
Speaker 1: smoking and micro gravity. That's it. Sorry, Uh, but so hey,
Speaker 1: we're saying why it's going to be a problem, uh
Speaker 1: to to build these environments. But we don't want to
Speaker 1: end on a downer because I've got something optimistic to say.
Speaker 1: To revisit a comment we made earlier. If you're willing
Speaker 1: to limit your ambitions, artificial gravity starts looking a lot
Speaker 1: more achievable. If only a small part of your spacecraft
Speaker 1: needs gravity, or if you're willing to settle for significantly
Speaker 1: less than Earth gravity, you've got a lot more options, right.
Speaker 1: For example, the rotating sphere compartment in two thousand one
Speaker 1: of Space Odyssey. They say it produces only about the
Speaker 1: gravity of the surface of the Moon. That's not a lot,
Speaker 1: but it might be enough that you can sort of
Speaker 1: jog like the character does. Uh. Basically, it's better than nothing.
Speaker 1: Things still fall towards the floor, even if it's not
Speaker 1: quite like being on Earth. And we mentioned some of
Speaker 1: those tests earlier, tests on human subjects in the nineteen
Speaker 1: sixties and these parabolic flights to basically determine what was
Speaker 1: tolerable or acceptable to people, you know, and they found
Speaker 1: out that zero point two G is actually a lot
Speaker 1: better than zero point one G. So there's like a
Speaker 1: pretty steep drop off point about what's acceptable somewhere in
Speaker 1: that range that normal human activities were mostly doable starting
Speaker 1: at about zero point two G. At about zero point
Speaker 1: five G, once you get to half of earth gravity,
Speaker 1: subjects felt about as sure of their movements as they
Speaker 1: did at one G. So once you're halfway there, it's
Speaker 1: basically good enough to do your movements and you know,
Speaker 1: maybe even sleep better at night. Yeah, all right, So
Speaker 1: there you have it. Artificial gravity. Uh, not to be
Speaker 1: confused with anti gravity. That's an entirely different podcast there. Now,
Speaker 1: how many times did we accidentally say anti gravity in
Speaker 1: this episode today? None that I know of, but there
Speaker 1: could be. Doesn't how many are later? I kept catching
Speaker 1: myself doing it in the notes. I kept I kept
Speaker 1: typing in um anti gravity, and I have to go
Speaker 1: back and it was like, not anti gravity because anti
Speaker 1: gravity is sort of sort of even though it's fun
Speaker 1: and science fiction as well, it's sort of a dirty
Speaker 1: word in scientific research. There are other terms that you
Speaker 1: would use. But but again that's a that's a topic
Speaker 1: for another time. If you guys want to discuss anti gravity,
Speaker 1: we can do that in a later date. Anti gravity.
Speaker 1: It's actually fairly simple. It's commonly known as jumping and lifting.
Speaker 1: All right, Well, don't spoil it all, don't spoil it all,
Speaker 1: joke alright. So hey, if you want to listen to
Speaker 1: more episodes of Stuff to Blow Your Mind, you want
Speaker 1: to explore past episodes, and we have a bunch of them,
Speaker 1: many of which deal with space and space exploration. Head
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