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Ginseng1
Elegant Universe



Registered: 09/02/04
Posts: 3,310
Last seen: 9 years, 7 months
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The path of least resistance...
#8360118 - 05/04/08 02:01 AM (16 years, 19 days ago) |
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What kind of motion is this?
I understand that the degree at which space is curved by large objects in space define their path of least resistance in proportion to their masses Moon arouns planets, planets around suns, suns around supermassive blackholes...
What kind of energy gives it static motion?
-------------------- Flowing through beginningless time since time without beginning...
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DieCommie


Registered: 12/11/03
Posts: 29,258
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Re: The path of least resistance... [Re: Ginseng1]
#8360189 - 05/04/08 02:44 AM (16 years, 19 days ago) |
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Ive never heard the orbit of massive objects described as a path of least resistance. Things orbit each other because they follow geodesics. Real space is non-euclidean, which means the shortest distance between two points is not a straight line. Geodesics are the shortest distance between two points in non-euclidean space. When gravity is strong enough, and the energy of the orbiting body is right, the geodesic is a circle/ellipse which makes the orbiting body to travel around and around.
Things taking the path of least resistance is like water flowing downhill, or electrons following conductors. In these cases, the objects do not follow geodesics.
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Ginseng1
Elegant Universe



Registered: 09/02/04
Posts: 3,310
Last seen: 9 years, 7 months
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Re: The path of least resistance... [Re: DieCommie]
#8360276 - 05/04/08 03:14 AM (16 years, 19 days ago) |
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Quote:
Orbital velocity is the velocity needed to achieve balance between gravity's pull on the satellite and the inertia.
So why do satellites fall back down to Earth? I thought it was because they ran out of juice and no longer could maintain a certain orbital velocity. They require bursts of energy to keep it at a fixed velocity, no?
What do orbital velocities, escape velocities have to do with geodenics and a non-eclidean space? I am speaking of the path of least resistance (balance) in terms of orbital velocity. Where do these massive objects get their fixed orbital velocities from if satellites can't achieve it without bursts of energy? Why moons but not satellites?
-------------------- Flowing through beginningless time since time without beginning...
Edited by Ginseng1 (05/04/08 03:17 AM)
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Anno
Experimenter




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Re: The path of least resistance... [Re: Ginseng1]
#8360456 - 05/04/08 05:44 AM (16 years, 19 days ago) |
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The satellites are slowed down by the friction since they are flying through a very, very thin atmosphere.
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Seuss
Error: divide byzero



Registered: 04/27/01
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Re: The path of least resistance... [Re: Ginseng1]
#8360545 - 05/04/08 07:00 AM (16 years, 19 days ago) |
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> Orbital velocity is the velocity needed to achieve balance between gravity's pull on the satellite and the inertia.
And balance can be misleading. For example, the Earth's moon is actually getting more and more distance with each orbit... but the change is so small that we cannot tell without using very sensitive measuring that it is moving away at all.
> They require bursts of energy to keep it at a fixed velocity, no?
Yes, but only because the atmosphere is acting as friction slowing them down. From time to time they need to increase their velocity a bit to maintain proper orbit.
> Why moons but not satellites?
It has to do with both mass of the moon (and a moon is a satellite!) and the distance from a planet and how much atmosphere (if any) the planet (and moon) have. More massive objects are more difficult to move.
-------------------- Just another spore in the wind.
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