# Back and forward orbit [around gravitating objects]

by Edi
Tags: levitate, orbit
P: 634
 Quote by Edi And here is the same picture with the tube around. The blue represents magnetic fields. As you can see, no magnetic field is pushing from beneath - just from the sides bouncing the object and from above holding the tube itself against the object being bounced [at orbital velocities]. :
Ah! That's enlightening. Can you draw the forces on the "object" and the "tube", possibly in two separate figures (to avoid confusion)?
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P: 10,382
 Quote by Edi .. that the tube-object system, as a whole, is not orbiting and is relatively stationary. 5 meters over your house, for example. All energy losses will be dealt with a power source.. System can be made even more complicated [and better] with several layers vacuum tubes .. like an engine, really. It would be an engine.
No, absolutely not. First, as I explained already, your tube is not going to be accelerated in the opposite direction enough to counteract it's greater mass. It will just end up slowing down and falling from orbit after the first collision until the 2nd collision accelerates back up again. The system as a whole would just stay in a normal orbit. Not stay stationary above the Earth.

Second, you cannot accelerate anything instantly, which means it takes time for you to reverse the direction of the bouncing object, during which time your device will fall from orbit.

Third, unless you are throwing miniscule amounts of matter around you're just going to annihilate your entire device when the object hits the tube.
P: 168
 Quote by Drakkith No, absolutely not. First, as I explained already, your tube is not going to be accelerated in the opposite direction enough to counteract it's greater mass. It will just end up slowing down and falling from orbit after the first collision until the 2nd collision accelerates back up again. The system as a whole would just stay in a normal orbit. Not stay stationary above the Earth. Second, you cannot accelerate anything instantly, which means it takes time for you to reverse the direction of the bouncing object, during which time your device will fall from orbit. Third, unless you are throwing miniscule amounts of matter around you're just going to annihilate your entire device when the object hits the tube.
"The object in a string" can pretty much solve all that, cant it?

More on that, see this: the object with a given speed would be in high orbit, without anything else - just a normal orbit.
Now, if you put the whole bouncing system on the object, the height above the planet decreases but eventually reaches point, where "upwards" push from the object cancels out the downwards push..

Even more on that - the tube can be the same mass as the object.
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P: 10,382
 Quote by Edi "The object in a string" can pretty much solve all that, cant it?
How so?

 More on that, see this: the object with a given speed would be in high orbit, without anything else - just a normal orbit. Now, if you put the whole bouncing system on the object, the height above the planet decreases but eventually reaches point, where "upwards" push from the object cancels out the downwards push..
What are you talking about? Stop changing the system if you want to have any chance of working through this. Look at ONE example at a time.

 Even more on that - the tube can be the same mass as the object.
Sure. But it's still going to fall from orbit. You will not be able to keep the system as a whole stationary over some part of the Earth unless you are in a geosync orbit. The center of mass of the system MUST be in a stable orbit.
 P: 168 I see this is going nowhere, so lets start from the beginning, step by step. First, what happens when you put additional mass on something that is already in orbit? That something + additional mass decreases orbital height and concludes at a stable lower orbit, right?
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P: 10,382
 Quote by Edi I see this is going nowhere, so lets start from the beginning, step by step. First, what happens when you put additional mass on something that is already in orbit? That something + additional mass decreases orbital height and concludes at a stable lower orbit, right?
No, you cannot just put mass onto something. You would have to physically shoot it up there with a rocket or some other means.
P: 168
 Quote by Drakkith No, you cannot just put mass onto something. You would have to physically shoot it up there with a rocket or some other means.
So you shoot it up there. Or the object caches something that is already up there.
The additional mass impact would decrease the objects speed and, accordingly, its orbital height. Then you can use whatever means you like to accelerate the object and the object + additional mass would gain orbital height again.
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P: 10,382
 Quote by Edi So you shoot it up there. Or the object caches something that is already up there. The additional mass impact would decrease the objects speed and, accordingly, its orbital height. Then you can use whatever means you like to accelerate the object and the object + additional mass would gain orbital height again.
That depends on how the object "catches" it. If it's similar to 2 spacecraft docking then nothing happens because they were already going the same speed. They stay in the same orbit.

If the two collide because of a difference in speed or direction, then their new orbit will be different depending on the nature of the collision.
P: 168
 Quote by Drakkith That depends on how the object "catches" it. If it's similar to 2 spacecraft docking then nothing happens because they were already going the same speed. They stay in the same orbit. If the two collide because of a difference in speed or direction, then their new orbit will be different depending on the nature of the collision.
The second scenario you mentioned.
So the new orbit will be different. Lower, if the added mass was moving slower.
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P: 10,382
 Quote by Edi The second scenario you mentioned. So the new orbit will be different. Lower, if the added mass was moving slower.
Sure. It's a bit more complicated, but let's go with that.
 P: 168 Ok. Now picture this: Object A has an object B held stably above it using magnetic fields. A levitating superconductor B with the base as object A. You accelerate directly only object A - will object B still come along with the acceleration and they both will gain orbital height?
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P: 10,382
 Quote by Edi Ok. Now picture this: Object A has an object B held stably above it using magnetic fields. A levitating superconductor B with the base as object A. You accelerate directly only object A - will object B still come along with the acceleration and they both will gain orbital height?
No, you can't do this with magnetic fields. Not in this manner. You either need to connect them together physically, or extend object A so that it surrounds object B.
Edit: I think at least, I'm not quite 100% sure on this.

However, you are correct that if you keep object A and B together by whatever means, they will accelerate together.
 P: 168 OK. So if, for whatever reason, no magnetic fields, then the system gets real extreme (material wise) Instead of magnetic field, the object B would be sliding on object A. (extreme, but bare with me) (maybe superfluid to "oil" it?) If you accelerate object A in this scenario, where object B is sitting on A with a superfluid between them - object A, as it is accelerated and gaining height, would push object B UP along with it. For short amount of time (depending on how long those objects are), but still would push object B up?
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P: 10,382
 Quote by Edi OK. So if, for whatever reason, no magnetic fields, then the system gets real extreme (material wise) Instead of magnetic field, the object B would be sliding on object A. (extreme, but bare with me) (maybe superfluid to "oil" it?) If you accelerate object A in this scenario, where object B is sitting on A with a superfluid between them - object A, as it is accelerated and gaining height, would push object B UP along with it. For short amount of time (depending on how long those objects are), but still would push object B up?
If there is no friction and you are accelerating it forward, then no. Object B will not accelerate with object A. If you are accelerating it "up", then yes, object B will accelerate with object A unless it slides off.
P: 168
 Quote by Drakkith If there is no friction and you are accelerating it forward, then no. Object B will not accelerate with object A. If you are accelerating it "up", then yes, object B will accelerate with object A unless it slides off.
Yes.
More precisely, it would not as much push it up, but it will hold object B from falling down for the time being or, at least, slow down B's decent? (assumed both started with no orbital speed at all.)
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P: 10,382
 Quote by Edi Yes. More precisely, it would not as much push it up, but it will hold object B from falling down for the time being or, at least, slow down B's decent? (assumed both started with no orbital speed at all.)
No, both fall at the same rate.
P: 168
 Quote by Drakkith No, both fall at the same rate.
If object A is accelerated to orbital speeds it will not fall at all. It will fall around the planet, but not directly down.

Yes.
More precisely, object A would not as much push object B up while accelerated/ moving at orbital speeds, but it will hold object B from falling down for the time being or, at least, slow down B's decent? (assumed both started with no orbital speed at all.)
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P: 10,382
 Quote by Edi If object A is accelerated to orbital speeds it will not fall at all. It will fall around the planet, but not directly down.
...but that isn't what you said...

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