Gravitation independnet of motion/momentum?

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Discussion Overview

The discussion explores the relationship between gravitational force and the motion or momentum of masses within a gravitational field. Participants examine whether variations in momentum affect the gravitational influence experienced by a mass and how this relates to classical and relativistic physics. The conversation touches on concepts of instantaneous force, Newton's laws, and the nature of gravitational interactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question whether the momentum of a small mass affects the gravitational force it experiences at a given radius from a large mass.
  • One participant asserts that classical gravitational acceleration is independent of velocity or momentum, relying solely on mass and distance.
  • Another participant draws an analogy between gravitational force and the impact force experienced by a golf ball, suggesting that the instantaneous force may differ based on the ball's motion.
  • There is a discussion about whether gravitational force is applied instantaneously at a specific radius and how this relates to Newton's third law.
  • Some participants note that in general relativity, gravity may depend on both mass and momentum, introducing complexity based on the chosen reference frame.
  • One participant expresses confusion about the interaction of forces and the point of action, questioning how reaction forces are characterized in relation to gravitational interactions.

Areas of Agreement / Disagreement

Participants generally disagree on the influence of momentum on gravitational force, with some asserting it has no effect while others suggest that relativistic considerations may introduce nuances. The discussion remains unresolved regarding the implications of momentum in gravitational interactions.

Contextual Notes

Participants highlight the distinction between classical and relativistic views of gravity, noting that the treatment of gravitational force may vary based on the reference frame and the definitions used. There are unresolved questions about the nature of instantaneous forces and their application in gravitational contexts.

  • #31
If you want to avoid action at a distance, but still want momentum conservation, the you have treat the field as an object that carries momentum. But the force is still independent of the motion.
 
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  • #32
OK, so assigning the reaction forces to the field momentum... then at the two objects' locations there are two forces, the gravitational force applied by the field to the object, and the object's inertial resistance to acceleration applied back to the field.

So that disposes of bare "action at a distance", but it does that by putting in its place "maintenance of a field at a distance"...

So the field is being "pushed" by the object's reaction, and the field is being pushed oppositely and equally by the other object's reaction, and since the field is a sum of the two objects' fields, the net is balanced... the 3rd law.

Is that it?
 

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