h a l f b a k e r y"It would work, if you can find alternatives to each of the steps involved in this process."
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Basically one of those carnival rides that's a spinning bowl that pins everybody against the back wall. With this you're doing cardio, pushup, situps etc, but you're two or three times your normal weight.
Good for space exercising too. Maybe use the onboard water supply as an adjustable counterweight.
Bad example
https://youtube.com...si=GaUpwrmNuS1yhvob [doctorremulac3, Mar 18 2025]
Spin gravity in sci-fi
https://youtu.be/C4...si=bxvBaXSSBYLHRfqR [21 Quest, Mar 19 2025]
Prior Art
https://news.mit.ed...-gravity-space-0702 The basic idea has been around a while. [neutrinos_shadow, Mar 19 2025]
Topical Study
https://journals.pl...ournal.pone.0234361 Motion sickness was "tolerable"... [neutrinos_shadow, Mar 19 2025]
More related stuff I just found
https://technology....gov/patent/TOP2-311 Non-rotating station with habitats on rails. [neutrinos_shadow, Mar 20 2025]
Moon trains
https://www.nextbig...-moon-and-mars.html Seems I'm not the first to think of it (because it's an obvious method) [neutrinos_shadow, Mar 20 2025]
[link]
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This, on a large scale, was how they achieved artificial gravity on Babylon 5 (if you haven't seen that show, it's a real sci-fi treat, even despite the REALLY poorly aged special effects). Big cylindrical space station, and they kept it rotating at a steady pace. The station was arranged inside the cylinder along the inner surface. [+] |
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Coriolis forces are the biggest problem with centrifuge arrangements. Basically, bigger radius is better. Little ones like in "2001" would be almost un-useable. |
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Yea, unless you're talking miles wide that's gonna be a factor. |
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I would think you could probably increase your resilience to motion sickness with practice maybe. |
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In case you didn't already know; If we were to hollow out the moon, (if it isn't hollow already...), the inner surface would equal Earth's land masses. If spun at the right speed everything along the equators would be at 1 Earth gravity with un-climable mountains on either side and you'd be looking at lakes and city lights above your head. |
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Centrifugal forces would trap any atmosphere and the poles of the newly rotating moon could be retracted with no loss of atmosphere. |
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True story... other than the inner surface equalling Earth's land masses. That's just something I read one time and can not confirm. |
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You could fly into and out of the spinning moon without any air-locks. |
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Earth's land area is about 4 times the surface of the Moon. The Moon is pretty big as far as moons go, but Earth is a lot bigger (& only 30% is "land").
Getting the moon spinning speed would be difficult given the "tide lock" it has with Earth. I guess you could use the Earth-Moon line as your axis, which would be weird.
<Throws some numbers about> Needs to rotate at 1.36 rev/hour (32.7 rev/day) for 1g near the surface (equator of rotation), which is faster than I expected...
Alternatively, put a train in a tunnel (or on the surface) going 16,051km/hr... |
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And reading conversations like these, is why I love the HB. |
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The idea themselves are a cover for the real payoff. |
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//If spun at the right speed// |
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How fast would that be? Easy math, centrifugal acceleration (a) = Velocity^2/radius, to achieve 1G(9.8 m/s/s) with the moon radius at 1737km we'd need an instantaneous linear velocity at the surface of 4125m/s which is just shy of 10,000mph or 1 rotation every 44 minutes. |
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//<Throws some numbers about> Needs to rotate at 1.36 rev/hour (32.7 rev/day) for 1g near the surface // |
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I just did unnecessary mathematics because.... |
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I'm not sure a hollow moon would hold together under that kind of force, quite a lot of work goes into making buildings hold up to 1G, and they're made of reinforced concrete and the like. Also, what's happening to the rock we remove? Presumably we're piling it up on the surface? In order to stop it all flinging itself into space when we spin the moon up, we're going to need a truly epic amount of UV resistant space-curing adhesive. |
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However, if the core material is selectively placed, that would be deliberately in a ring around the circumference "under" the habitable zone, we could feasibly double the mass, boosting the moon G from 0.16 to 0.3 or so. That's probably workable on it's own. As it turns out, the moon has a solid iron core, but it's tiny. The mantle is rich in iron silicates. If we extract the iron, and therefore O2 & silicon, we can have a much denser iron layer just under the habitable zone. I think that gets us to 0.5 or so. |
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Do we need 1G? Well, we don't want the atmosphere boiling off into space, is that an issue? Escape velocity on 1G Earth is ~11km/s and O2 has a thermal Velocity at normal temps in the 0.4km/s range, so that's not a problem at 0.5G. What happens to pressure? Well, that's determined by the atmospheric mass and gravity, so with an Earth-equivalent atmosphere, it would be 0.5 Atmospheric pressure, you'd need ~30km of atmosphere. Leading to 0.5 pO2, you could compensate with double the O2 concentration. |
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...I just see things in my head, and then try to convey them with the limited vocabulary available to me. |
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If the moon were hollowed out it would become much bigger and yet weigh no more than it does now so no tides would be affected. |
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This might be where the whole equalling Earth's land mass came from. I don't know. |
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What I see in my head is a habitable enclosure spinning at a speed which would equal 1 G at the equator and have open poles allowing spacecraft to enter and exit without air-locks. |
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I will need years to understand your math. It only takes seconds to understand my vision. |
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By all means use your math. I love it. I learn from it... |
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...but I don't understand it...yet. |
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My favorite thing is when mathemeticians and scientists run with my brain farts. |
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I fucking love it. Carry on. |
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I'm a long way from being a mathematician, but it's nice to stretch the legs of the mind occasionally. |
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