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Why no Artificial Gravity ??

Just thinking said:
An interesting side note about being in a rotating torus -- assume you are feeling normal gravity as you stand in one position on the floor, your head pointed toward the center of rotation. If you decided to start running in the opposite direction of rotation, you would start to experience less G's -- and this might enable to run even faster. If you could go fast enough to match the linear speed of the torus (but in the opposite direction) you would become weightless. You would float -- but the body of the torus would now spin relative to you. You would fly through the compartments (hopefully without hitting anything) as if you were Superman.
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In a vacuum maybe. Air resistance would be the killer, also how fast you can move your legs. Now with a bicycle...
 
ponderingturtle said:
In a vacuum maybe. Air resistance would be the killer, also how fast you can move your legs. Now with a bicycle...
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If it were pressurized to 1 atmosphere perhaps, but in spacecraft the rule is basically oxygen rich with an inert at 3 psi (or maybe 5), which is considerably less. Anyway, you're right that eventually air resistance would slow you down, or in this case, speed you up.
 
ponderingturtle said:
Because to get much gravity you are talking a truly huge structure. And then you get all kinds of strange rotational effects like strong Coriolis effects when you walk.
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Hahah I could picture the astronauts landing on mars and not being able to walk straight because of compensating for the coriolis force. They would all be drifting to the left....
 
ponderingturtle said:
Well sort of right but not really. If you drop something it continues moving in a straight line, but the floor and you are not so it will hit the floor as the floor is pulled into its path by the centripetal acceleration.

It might not fall straight down but at a weird angle but it would fall. I need to find my old advanced mechanics books and look at these equations again.
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My take on this is that centrifugal/centripetal force shares many qualities of "mass attraction" gravity, but there are equally as many non-parallels.

Objects tossed in a straight line across a spinning ring environment would follow a similar parabolic ballistic path if re-mapped (unwrapped) to its "flat" Earth equivalent. However, it is possible to, in the "spinning ring" environment, to launch an object in an equal and opposite direction from the rotational environment such that it maintains is radial distance from Cm (center of mass), "hovering" at the same elevation from the floorboards. Picture a rotating ring with a stationary dot near the inside edge. To remap this scenario means, on Earth, a projectile would never lose altitude and must glide along at a constant elevation until obstructed or stopped. If Delta Airlines knew of this they'd be in good shape.

Another non-parallel case near Earth is geostationary satellites, fixed over a constant geographic point. There is no equivalent of this effect in a spinning ring except at the center of rotation. It's almost the exact opposite, kinda like a candle in the center of a spherical reflector instead of bouncing single rays in all directions from the outside of a reflective ball.

Yet another non-parallel is low-Earth orbits: eg. Shuttle, surveilance satellites, space junk, etc. These must be traveling significantly faster relative to a point at sea level to maintain orbit (which is a function of centrifugal force) because they're always in a state of freefall that happens to match the Earth's curvature.

Odder still is that the remapping effects are somewhat reversed. In the first example of a "hovering" body near "ground" within a spinning ring versus the low-Earth orbit variety, the planes of reference, outward or inward, are diametrically opposed (forgive the geek pun.) It's also why the Earth's center is experiencing the same Zero-G effects as we speak.

Someone please correct me if I'm mistaken in my understanding.
 
Brian Jackson said:
To remap this scenario means, on Earth, a projectile would never lose altitude and must glide along at a constant elevation until obstructed or stopped. If Delta Airlines knew of this they'd be in good shape.
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Hint: Delta knows about it, but it's NASA that owns the equipment.
 
Just thinking said:
If it were pressurized to 1 atmosphere perhaps, but in spacecraft the rule is basically oxygen rich with an inert at 3 psi (or maybe 5), which is considerably less. Anyway, you're right that eventually air resistance would slow you down, or in this case, speed you up.
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No you can only move you leg so fast so you can not get a relative velocity to the wall of greater than that. It has to do with the mass and how much force the muscles exert and how fast they can contract.

If you can only move your foot at say 45 mph then you will not be able to run faster than 45 mph.
 
Brian Jackson said:
My take on this is that centrifugal/centripetal force shares many qualities of "mass attraction" gravity, but there are equally as many non-parallels.

Objects tossed in a straight line across a spinning ring environment would follow a similar parabolic ballistic path if re-mapped (unwrapped) to its "flat" Earth equivalent. However, it is possible to, in the "spinning ring" environment, to launch an object in an equal and opposite direction from the rotational environment such that it maintains is radial distance from Cm (center of mass), "hovering" at the same elevation from the floorboards. Picture a rotating ring with a stationary dot near the inside edge. To remap this scenario means, on Earth, a projectile would never lose altitude and must glide along at a constant elevation until obstructed or stopped. If Delta Airlines knew of this they'd be in good shape.
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Its also called being in orbit if you are talking about gravity.

Someone please correct me if I'm mistaken in my understanding.
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Most of those effect are not really relevent to every day life. It is the much stronger corrilis effects that make things go really weird
 
There were a couple of scenes in Babylon 5 which showed that it had a baseball diamond, and I remember thinking, "Man, would that ever be hard to play on a rotating space station!"
 
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toddjh said:
There were a couple of scenes in Babylon 5 which showed that it had a baseball diamond, and I remember thinking, "Man, would that ever be hard to play on a rotating space station!"
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Try golf.

Or there was my favorite scifi sport, pogo stick races to circumnavigate Ceres, where a rule is you are disqualified if you attain escape velocity.
 
I thought I read that some designs under consideration called for the astronauts to sleep in a rotating drum. This obviates the problem of a "gravity" gradient between the astronauts' feet and heads because their entire bodies lie along the rotating wall.

This plan was put forward after, IIRC, experiments showed that even short stays in such an environment was sufficient to greatly reduce the negative effects of zero-g.
 
Cuddles said:
Imagine this. You have a hollow torus in space that is not rotating. You place an object in the torus so that it is not in contact with the walls. Now start the torus rotating so that the object stays out of contact with it. What happens to the object?

Absolutely nothing. It stays happily floating there. Hence, not gravity.
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You are correct.

In order for an object inside the rotating spacecraft to feel the pull of artificial gravity, the object must be in motion relative to the center of rotation of the spacecraft. In the absence of air friction, an object that is not moving would remain in place (even when not at the center of motion) and would not "fall" toward the hull. This illustrates the fact that artificial gravity is a result of the object's circular motion and its reaction against the similarly moving spacecraft hull; artificial gravity is not an attraction between the object and the hull.



http://en.wikipedia.org/wiki/Artificial_gravity
 
MilwaukeeMike said:
This illustrates the fact that artificial gravity is a result of the object's circular motion and its reaction against the similarly moving spacecraft hull; artificial gravity is not an attraction between the object and the hull.
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That's only real artificial gravity. Sci-fi artificial gravity comes from a generator that magnifies the gravitons in a ship's deck plating.
 
Loss Leader said:
That's only real artificial gravity. Sci-fi artificial gravity comes from a generator that magnifies the gravitons in a ship's deck plating.
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Actually, "artificial gravity generators" might not be that far down the road.... Read this.

Magnetism

A similar effect to gravity has been created through diamagnetism. It requires magnets with incredibly powerful magnetic fields. At present such devices have been made that were able to levitate at most a small frog, and thus producing a 1 g field to cancel the Earth's; yet it required a magnet and system that weighs thousands of kilograms and is kept superconductive with expensive cryonics and required 6 MW of power.

Such extremely strong magnetic fields are far above the permitted levels, and safety for use with humans is at best unclear. In addition, it would involve avoiding any non-diamagnetic materials near the strong magnetic field required for diamagnetism to be evident. Some other disadvantages of using magnetism on a spaceship are found here: http://www.madsci.org/posts/archives/2005-04/1112370655.Ph.r.html


Gravity generator/gravitomagnetism

In science fiction, artificial gravity (or cancellation of gravity) is sometimes present in spacecraft that are neither rotating nor accelerating. At present there is no confirmed technique that can produce gravity other than sheer mass. There have been many claims over the years of such a device. Eugene Podkletnov, a Russian engineer, has claimed since the early 1990s to have made such a device consisting of a spinning superconductor producing a powerful Gravitomagnetic field, but there has been no verification or even negative results from third parties. In 2006 a research group funded by ESA claimed to have created a similar device that demonstrated positive results for the production of gravitomagnetism, although it produced only 100 millionths of a g


http://en.wikipedia.org/wiki/Artificial_gravity
 
MilwaukeeMike said:
Actually, "artificial gravity generators" might not be that far down the road.... Read this.

Magnetism

A similar effect to gravity has been created through diamagnetism. It requires magnets with incredibly powerful magnetic fields. At present such devices have been made that were able to levitate at most a small frog, and thus producing a 1 g field to cancel the Earth's; yet it required a magnet and system that weighs thousands of kilograms and is kept superconductive with expensive cryonics and required 6 MW of power.
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The strength of those fields you will get all kinds of induced currents from motion, and if you bring something paramagnetic or god forbid ferro magnetic you are in real trouble.
 
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