Moontanman Posted November 29, 2017 Share Posted November 29, 2017 In a spinning torus a reasonable imitation of gravity can be produced, even though from the outside is is obviously not flat but curved. But... What if you spun a cube? Even though the sides are flat from an outside observer would an interior observer feel like he was walking up hill and down as he progressed around the inside of the spinning cube? Link to comment Share on other sites More sharing options...
Phi for All Posted November 29, 2017 Share Posted November 29, 2017 Wouldn't stepping onto a wall be supported as much as the "floor" he started from? I'm not sure why there would be an uphill/downhill difference on the inside of the spinning cube. But if the cube is big enough, I think it would feel just like the torus, except the corners require a different step than a flat floor/wall, perhaps. 1 Link to comment Share on other sites More sharing options...
Moontanman Posted November 29, 2017 Author Share Posted November 29, 2017 3 minutes ago, Phi for All said: Wouldn't stepping onto a wall be supported as much as the "floor" he started from? I'm not sure why there would be an uphill/downhill difference on the inside of the spinning cube. But if the cube is big enough, I think it would feel just like the torus, except the corners require a different step than a flat floor/wall, perhaps. I was trying to look at it from the standpoint of water, in a torus the water would look like a long lake or stream. My intuition tells me that water would pool up in the corners of a spinning cube but I am not sure. Link to comment Share on other sites More sharing options...
MigL Posted November 29, 2017 Share Posted November 29, 2017 The radial distance to the corners of the cube is larger, so the angular speed is different as is the apparent force. And pressurization is easier with smoothly curved surfaces as opposed to sharp corners. 1 Link to comment Share on other sites More sharing options...
Strange Posted November 29, 2017 Share Posted November 29, 2017 At the the centre of any face of the cube, the centrifugal force would be normal to the surface. As you move away from the centre, the force vector would move away from the "vertical" and it would feel (I think) like you were asking downhill. So the plane surface would feel like a domed surface. 2 Link to comment Share on other sites More sharing options...
Phi for All Posted November 29, 2017 Share Posted November 29, 2017 3 minutes ago, MigL said: The radial distance to the corners of the cube is larger, so the angular speed is different as is the apparent force. Would this tend to make the water pool in the corners as the cube rotated? Link to comment Share on other sites More sharing options...
MigL Posted November 29, 2017 Share Posted November 29, 2017 The 'fictitious' centrifugal force is at play here, because of the rotating frame, and is equivalent to Mrw^2, where M=mass, r=radial distance and w=angular speed. In the corners both r and w are larger, so they feel a greater apparent force. So, yeah, walking to the center of a face would be walking 'up-hill' and water would pool in the corners. 2 Link to comment Share on other sites More sharing options...
Phi for All Posted November 29, 2017 Share Posted November 29, 2017 4 minutes ago, MigL said: So, yeah, walking to the center of a face would be walking 'up-hill' and water would pool in the corners. And walking from the center to a corner would feel like downhill where the water pools. I understand where the Moontanman is coming from now. Link to comment Share on other sites More sharing options...
Moontanman Posted November 29, 2017 Author Share Posted November 29, 2017 Thanks guys, this makes for some interesting possibilities... 1 hour ago, MigL said: The 'fictitious' centrifugal force is at play here, because of the rotating frame, and is equivalent to Mrw^2, where M=mass, r=radial distance and w=angular speed. In the corners both r and w are larger, so they feel a greater apparent force. So, yeah, walking to the center of a face would be walking 'up-hill' and water would pool in the corners. Would the observer feel lighter at the center of a face than at the corners as well? Link to comment Share on other sites More sharing options...
Strange Posted November 29, 2017 Share Posted November 29, 2017 11 minutes ago, Moontanman said: Thanks guys, this makes for some interesting possibilities... Would the observer feel lighter at the center of a face than at the corners as well? Yes. But if the difference was large enough to be noticeable then I suspect the tidal forces would be very uncomfortable, if not dangerous. 1 Link to comment Share on other sites More sharing options...
steveupson Posted November 29, 2017 Share Posted November 29, 2017 3 hours ago, MigL said: The 'fictitious' centrifugal force is at play here, because of the rotating frame, and is equivalent to Mrw^2, where M=mass, r=radial distance and w=angular speed. In the corners both r and w are larger, so they feel a greater apparent force. So, yeah, walking to the center of a face would be walking 'up-hill' and water would pool in the corners. angular speed is the same, linear speed is greater 2 Link to comment Share on other sites More sharing options...
Janus Posted November 30, 2017 Share Posted November 30, 2017 For a person walking around the square, it would be similar to walking from one vee shaped valley to another with a hill in between. Something like this. Though the "hills" wouldn't curve but act more like a flat surface tilting as you walk. 1 Link to comment Share on other sites More sharing options...
MigL Posted November 30, 2017 Share Posted November 30, 2017 Sorry Steve; you're absolutely right. The proper terminology is the first thing you forget when its not used regularly. Thanks for the correction. 1 Link to comment Share on other sites More sharing options...
Janus Posted November 30, 2017 Share Posted November 30, 2017 Here's another visualization of what walking around the spinning square would be like, showing 1 full side and part of two others: 4 Link to comment Share on other sites More sharing options...
Moontanman Posted November 30, 2017 Author Share Posted November 30, 2017 17 minutes ago, Janus said: Here's another visualization of what walking around the spinning square would be like, showing 1 full side and part of two others: Looks like it might be more than a bit weird! 2 Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted December 1, 2017 Share Posted December 1, 2017 That's awesome Janus. There should be a slight effect from which way it is spinning. So walking one way would have some different effects from the other depending on your speed. 1 Link to comment Share on other sites More sharing options...
mistermack Posted December 1, 2017 Share Posted December 1, 2017 I would add that if you find different levels of gravity desirable, a circular cross section could still provide that. You could simply go up a flight of stairs, to a level closer to the centre of rotation, and feel lighter. So just like on Earth, we would probably go upstairs to bed. In space stations on a gigantic scale, you could maybe go upstairs to lower gravity levels as you get older, or if you're not well. 1 Link to comment Share on other sites More sharing options...
Moontanman Posted December 1, 2017 Author Share Posted December 1, 2017 16 hours ago, Janus said: Here's another visualization of what walking around the spinning square would be like, showing 1 full side and part of two others: if it was quite large, several kilometers across it might not be too strange but a torus would be easier to support as an endless suspension bridge type deal.. Link to comment Share on other sites More sharing options...
J.C.MacSwell Posted December 1, 2017 Share Posted December 1, 2017 3 hours ago, mistermack said: I would add that if you find different levels of gravity desirable, a circular cross section could still provide that. You could simply go up a flight of stairs, to a level closer to the centre of rotation, and feel lighter. So just like on Earth, we would probably go upstairs to bed. In space stations on a gigantic scale, you could maybe go upstairs to lower gravity levels as you get older, or if you're not well. ...off to the basement to get some exercise in the "weight room" 1 Link to comment Share on other sites More sharing options...
Janus Posted December 2, 2017 Share Posted December 2, 2017 Just for the fun of it, here's the square habitat done with stair steps to make it easier to walk around the interior since near the corners, the slope approaches 45 degrees. The simulated gravity will be ~41% higher at the corners than it is in the middle of each side, so you would be dealing with more "weight" as well as a steeper incline there. Maybe it's just me, but there's something very "Esher-esque " about this image. 3 Link to comment Share on other sites More sharing options...
geordief Posted December 3, 2017 Share Posted December 3, 2017 1 hour ago, Janus said: Just for the fun of it, here's the square habitat done with stair steps to make it easier to walk around the interior since near the corners, the slope approaches 45 degrees. The simulated gravity will be ~41% higher at the corners than it is in the middle of each side, so you would be dealing with more "weight" as well as a steeper incline there. Maybe it's just me, but there's something very "Esher-esque " about this image. Or perhaps ;-) https://youtu.be/jk63Psr3wzY Link to comment Share on other sites More sharing options...
Strange Posted December 3, 2017 Share Posted December 3, 2017 Or this: 1 Link to comment Share on other sites More sharing options...
geordief Posted December 3, 2017 Share Posted December 3, 2017 (edited) 23 minutes ago, Strange said: Or this: Very impressive. What is it meant to be ? One step forward ,two steps back? Plus ca change? Edited December 3, 2017 by geordief Link to comment Share on other sites More sharing options...
Janus Posted December 3, 2017 Share Posted December 3, 2017 1 hour ago, geordief said: Or perhaps ;-) https://youtu.be/jk63Psr3wzY Love the song, but prefer the Noel Harrison version. Link to comment Share on other sites More sharing options...
Janus Posted December 3, 2017 Share Posted December 3, 2017 On 12/1/2017 at 5:47 AM, mistermack said: I would add that if you find different levels of gravity desirable, a circular cross section could still provide that. You could simply go up a flight of stairs, to a level closer to the centre of rotation, and feel lighter. So just like on Earth, we would probably go upstairs to bed. In space stations on a gigantic scale, you could maybe go upstairs to lower gravity levels as you get older, or if you're not well. On a small scale station, your flight of stair going from one level to another could look like this.* Now you could align the stair case with the axis of rotation, but then Coriolis effect would try to push you sideways as you climbed or descended. Even with the set up above, you'd want to point the staircase in the correct direction with respect to the rotation. Here you would want the rotation to be clockwise. This way, the Coriolis effect would tend to push you towards backwards( up-stair) when descending the staircase. It would also tend to push you backwards when climbing, but this would probably be easier to deal with while climbing than while descending. If worse came to worse, you could design "up" staircases and "down" staircases curving in opposite directions relative to the spin. (Just avoid trying to go down the up staircase) * I'm learning a new 3-D rendering software, so this is giving me an opportunity to play around with it 1 Link to comment Share on other sites More sharing options...
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