- #1
Riemannliness
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Here's a thought that was bugging me last night:
Lets say you placed a very long rigid pole (jokes kept to a minimum please) into orbit so that one end (end #1) faced the center of the earth, and the other (end #2) pointed out into space (So that the center of the Earth and all the points on the pole were more or less collinear).
To simplify, let's say that the pole is sufficiently large, and end #1 is at an orbital radius of r from earth; end #2 at radius 2r.
If you investigate the necessary orbital velocities of both ends [v=sqrt(GM[SUB]central[/SUB]/r)] then you'll find that: vend #2 = vend #1/sqrt2
Looking into it further you'll find that if it were geometrically possible, end #1 at this speed will complete 1 orbit for every 1/4 orbit of end#2
Assuming I haven't overlooked something trivial or made a careless mistake, how would the pole behave after it had been placed into proper orbit? What sort of mathematical tools would help me analyze the internal forces acting here? I was treating the ends as isolated as an example, but really this imbalance would occur all along the length of the object (and any orbiting object would experience this come to think of it).
I'm fairly certain that it couldn't stay in a stable orbit, in this orientation, if the only external force acting upon it was gravity. I'm just wondering if there could be a stable orbit for a rigid body like this, or if it would have some form of variable motion. There is no way to orient a straight line around a sphere so that all points on that line are equidistant from the sphere's center. Therefore there will always be some parts of this pole that are at a higher orbital radius than other parts, and thus different parts would try to move at different velocities.
Lets say you placed a very long rigid pole (jokes kept to a minimum please) into orbit so that one end (end #1) faced the center of the earth, and the other (end #2) pointed out into space (So that the center of the Earth and all the points on the pole were more or less collinear).
To simplify, let's say that the pole is sufficiently large, and end #1 is at an orbital radius of r from earth; end #2 at radius 2r.
If you investigate the necessary orbital velocities of both ends [v=sqrt(GM[SUB]central[/SUB]/r)] then you'll find that: vend #2 = vend #1/sqrt2
Looking into it further you'll find that if it were geometrically possible, end #1 at this speed will complete 1 orbit for every 1/4 orbit of end#2
Assuming I haven't overlooked something trivial or made a careless mistake, how would the pole behave after it had been placed into proper orbit? What sort of mathematical tools would help me analyze the internal forces acting here? I was treating the ends as isolated as an example, but really this imbalance would occur all along the length of the object (and any orbiting object would experience this come to think of it).
I'm fairly certain that it couldn't stay in a stable orbit, in this orientation, if the only external force acting upon it was gravity. I'm just wondering if there could be a stable orbit for a rigid body like this, or if it would have some form of variable motion. There is no way to orient a straight line around a sphere so that all points on that line are equidistant from the sphere's center. Therefore there will always be some parts of this pole that are at a higher orbital radius than other parts, and thus different parts would try to move at different velocities.
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