4 ms·

Wild idea: build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in i

Wild idea: build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. That would likely be something that fitness people and professional athletes would be interested in. And it's a good dry run for building and operating these things on Mars and the Moon. If we can make these things work on Earth, making them work in lower gravity is only going to be easier as the g-forces would be lower. A train or roller coaster on a slightly tilted circular track would probably do the job. A slight tilt would just move the gravity vector orthogonal to the floor.

yjftsjthsd-h 3y ago
> build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. Is that any better than ankle weights? Or wrist, I suppose.
- jjk166 3y ago
  The difference between weights on your body and higher gravity field is that with higher gravity all of you feels the force equally at the same time, so you're not putting excessive strain on certain parts of your body while neglecting others (such as internal structures).
amstan 3y ago
Why did nobody do this yet? It would totally be a great prototype for stuff in orbit.
- Cthulhu_ 3y ago
  Closest thing I can think of is rotating houses / restaurants, but they go very slowly. It would have to be big enough to avoid people getting dizzy, and even then it would still be a factor I think. That said, size/scale is less of a concern on the moon I would argue.
  - xnorswap 3y ago
    You inspired me to look up if there were many still going and I was saddened to discover there are no longer any operational ones left in the UK.
- jstanley 3y ago
  All parts would be spinning at the same angular velocity, so unless it's really far away from its centre of rotation (expensive, inconvenient) you'd experience more acceleration near the centre than at the edges. Maybe that doesn't matter.
  - scotty79 3y ago
    One of the commenters here has the right idea. Train riding forever on circular slanted track could easily house some living spaces, offices and gyms. You could book a stay there for few weeks and after that feel like you are walking on air once you come back to normal life.
    - Nevermark 3y ago
      Circular dome colony over a very large rotating space, running on concentric rings of superconducting rails. Spokes of slidable inner-outer weights to counter balance its residence’s movements. Running on reliable constant nuclear power, from a safe distance. Maximum gravity at the tilted edges. Only natural gravity at the center. Enter & exit from a tunnel that connects under the center. Aside from the challenges of location & distance from Earth, if we can build small mobile cities on water (mega cruise lines) on the untamed ocean in Earth gravity, surely a small stationary spinning platter city in low gravity is possible. I think humans are going to find out that one g has many uses besides health. Good for a lot of manufacturing too. Gravity is a stabilizer, vertical organizer, anchor. Just as low gravity will have many advantages. Being able to quickly “adjust” gravity, by moving location, will be significant.
      - eru 3y ago
        > Being able to quickly “adjust” gravity, by moving location, will be significant. Who is doing the adjusting and the moving? I don't think you'd want to move anything large. You'd build eg your factory in the environment where it's best; and build a second factory in a different environment, instead of moving them around. However, if you eg making computer chips, you might move those around between different environments, depending on the processing step.
- scoopr 3y ago
  I just keep thinking about this short film[0] that explores the views you can see with rotational artificial gravity, and how nauseating it could be :) [0] https://vimeo.com/869858712 https://vimeo.com/869858712 also available as https://www.youtube.com/watch?v=iiPmgW21rwY https://www.youtube.com/watch?v=iiPmgW21rwY
  - Nevermark 3y ago
    Just point the axis at the major body of interest, Earth, moon, Jupiter, etc., and it would slowly rotate in a stationary position, instead of spinning around you. Or align the axis with the major light source if that is different, like the sun for inner solar system locations, and at least the lighting won't keep moving around. Not much different from watching scenery go by in a vehicle then.
actionfromafar 3y ago
https://en.wikipedia.org/wiki/Tilting_train https://en.wikipedia.org/wiki/Tilting_train
- eru 3y ago
  You don't need to have a tilting train, you can just tilt the track.
vintermann 3y ago
Spinning stuff in air takes more energy than spinning stuff in a vacuum.
- Nevermark 3y ago
  If the track is enclosed in a smooth symmetric enclosure, either a circle or flat dome, the air within the enclosure will spin along with the train or other tracked constructions, instead of impeding them. I imagine some texturing on the inside of the enclosure could create small scale surface turbulence that even reduces the minimal friction there.
- eru 3y ago
  You would likely put these in air on the moon as well. Depends a bit on your design.
- jillesvangurp 3y ago
  But then we do operate trains in our atmosphere so this is a solvable problem. The advantage outside of our atmosphere is of course that aerodynamics don't matter, which indeed would make things more energy efficient. Also there would be no weather (or very little of it on Mars), no humidity.
Someone 3y ago
The acceleration needed to make a turn with radius r at speed v is. v²/r (https://courses.lumenlearning.com/suny-physics/chapter/6-2-centripetal-acceleration/ https://courses.lumenlearning.com/suny-physics/chapter/6-2-c...) If that combined that with earth’s gravity has to give you 1.1g, that has to be (via the Pythagorean theorem) about 0.2g or 2m/s². Let’s pick r = 100m. Then, v² has to be 20, giving as a velocity of about 16 km/hour. r = 1km would require about 50km/hour. Sounds doable, until you consider your “put gyms, hotels, swimming pool, living quarters, etc. in it”. That’s a lot of mass and space. Centrifuges that we put potential astronauts and fighter pilots in are a lot smaller. On the other hand, there’s the idea of “a massive floating railway, Maglev-style, which will travel along a track with a radius of 2.5 kilometers within an underground vacuum tunnel. The machine will run on excess energy generated from wind and solar, and it can reach speeds up to 2,000 km/h. When the renewable energy production is insufficient, the kinetic energy from the train movement will be reconverted and sent to the grid.” that engineers claim can be built (https://www.greenoptimistic.com/energy-train-mph/ https://www.greenoptimistic.com/energy-train-mph/). That would hit over 10g and weigh a lot more than that hotel. I can’t find updates, though.
- jillesvangurp 3y ago
  That's why I proposed using a train. Minus the swimming pool, totally doable to have one driving around at relatively low speeds. We use trains to move many tonnes of cargo around already. So, I don't see the mass as a show stopper.
- Someone 3y ago
  Reply to self: the MVP for this probably is to walk around with a backpack that’s 10% of your body weight. That’s a lot cheaper and for many sports likely would bring the same benefits.

yjftsjthsd-h 3y ago

> build one on earth to simulate 1.1G (or higher; whatever would still be comfortable) and put gyms, hotels, swimming pool, living quarters, etc. in it. Being in it for extended periods of time would build up muscles and bones. Is that any better than ankle weights? Or wrist, I suppose.

jjk166 3y ago
The difference between weights on your body and higher gravity field is that with higher gravity all of you feels the force equally at the same time, so you're not putting excessive strain on certain parts of your body while neglecting others (such as internal structures).

amstan 3y ago

Why did nobody do this yet? It would totally be a great prototype for stuff in orbit.

Cthulhu_ 3y ago
Closest thing I can think of is rotating houses / restaurants, but they go very slowly. It would have to be big enough to avoid people getting dizzy, and even then it would still be a factor I think. That said, size/scale is less of a concern on the moon I would argue.
- xnorswap 3y ago
  You inspired me to look up if there were many still going and I was saddened to discover there are no longer any operational ones left in the UK.
jstanley 3y ago
All parts would be spinning at the same angular velocity, so unless it's really far away from its centre of rotation (expensive, inconvenient) you'd experience more acceleration near the centre than at the edges. Maybe that doesn't matter.
- scotty79 3y ago
  One of the commenters here has the right idea. Train riding forever on circular slanted track could easily house some living spaces, offices and gyms. You could book a stay there for few weeks and after that feel like you are walking on air once you come back to normal life.
  - Nevermark 3y ago
    Circular dome colony over a very large rotating space, running on concentric rings of superconducting rails. Spokes of slidable inner-outer weights to counter balance its residence’s movements. Running on reliable constant nuclear power, from a safe distance. Maximum gravity at the tilted edges. Only natural gravity at the center. Enter & exit from a tunnel that connects under the center. Aside from the challenges of location & distance from Earth, if we can build small mobile cities on water (mega cruise lines) on the untamed ocean in Earth gravity, surely a small stationary spinning platter city in low gravity is possible. I think humans are going to find out that one g has many uses besides health. Good for a lot of manufacturing too. Gravity is a stabilizer, vertical organizer, anchor. Just as low gravity will have many advantages. Being able to quickly “adjust” gravity, by moving location, will be significant.
    - eru 3y ago
      > Being able to quickly “adjust” gravity, by moving location, will be significant. Who is doing the adjusting and the moving? I don't think you'd want to move anything large. You'd build eg your factory in the environment where it's best; and build a second factory in a different environment, instead of moving them around. However, if you eg making computer chips, you might move those around between different environments, depending on the processing step.
scoopr 3y ago
I just keep thinking about this short film[0] that explores the views you can see with rotational artificial gravity, and how nauseating it could be :) [0] https://vimeo.com/869858712 https://vimeo.com/869858712 also available as https://www.youtube.com/watch?v=iiPmgW21rwY https://www.youtube.com/watch?v=iiPmgW21rwY
- Nevermark 3y ago
  Just point the axis at the major body of interest, Earth, moon, Jupiter, etc., and it would slowly rotate in a stationary position, instead of spinning around you. Or align the axis with the major light source if that is different, like the sun for inner solar system locations, and at least the lighting won't keep moving around. Not much different from watching scenery go by in a vehicle then.

actionfromafar 3y ago

https://en.wikipedia.org/wiki/Tilting_train https://en.wikipedia.org/wiki/Tilting_train

eru 3y ago
You don't need to have a tilting train, you can just tilt the track.

vintermann 3y ago

Spinning stuff in air takes more energy than spinning stuff in a vacuum.

Nevermark 3y ago
If the track is enclosed in a smooth symmetric enclosure, either a circle or flat dome, the air within the enclosure will spin along with the train or other tracked constructions, instead of impeding them. I imagine some texturing on the inside of the enclosure could create small scale surface turbulence that even reduces the minimal friction there.
eru 3y ago
You would likely put these in air on the moon as well. Depends a bit on your design.
jillesvangurp 3y ago
But then we do operate trains in our atmosphere so this is a solvable problem. The advantage outside of our atmosphere is of course that aerodynamics don't matter, which indeed would make things more energy efficient. Also there would be no weather (or very little of it on Mars), no humidity.

Someone 3y ago

The acceleration needed to make a turn with radius r at speed v is. v²/r (https://courses.lumenlearning.com/suny-physics/chapter/6-2-centripetal-acceleration/ https://courses.lumenlearning.com/suny-physics/chapter/6-2-c...) If that combined that with earth’s gravity has to give you 1.1g, that has to be (via the Pythagorean theorem) about 0.2g or 2m/s². Let’s pick r = 100m. Then, v² has to be 20, giving as a velocity of about 16 km/hour. r = 1km would require about 50km/hour. Sounds doable, until you consider your “put gyms, hotels, swimming pool, living quarters, etc. in it”. That’s a lot of mass and space. Centrifuges that we put potential astronauts and fighter pilots in are a lot smaller. On the other hand, there’s the idea of “a massive floating railway, Maglev-style, which will travel along a track with a radius of 2.5 kilometers within an underground vacuum tunnel. The machine will run on excess energy generated from wind and solar, and it can reach speeds up to 2,000 km/h. When the renewable energy production is insufficient, the kinetic energy from the train movement will be reconverted and sent to the grid.” that engineers claim can be built (https://www.greenoptimistic.com/energy-train-mph/ https://www.greenoptimistic.com/energy-train-mph/). That would hit over 10g and weigh a lot more than that hotel. I can’t find updates, though.

jillesvangurp 3y ago
That's why I proposed using a train. Minus the swimming pool, totally doable to have one driving around at relatively low speeds. We use trains to move many tonnes of cargo around already. So, I don't see the mass as a show stopper.
Someone 3y ago
Reply to self: the MVP for this probably is to walk around with a backpack that’s 10% of your body weight. That’s a lot cheaper and for many sports likely would bring the same benefits.