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harrylentil
- 33
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Spin off from https://www.physicsforums.com/threads/what-gives-gravity-its-power-to-accelerate-objects.954961/#post-6053715
What is the physical property that gravity has that enables it to make an object go faster or, if it is resting on the ground, have weight?
In General Relativity (as I understand it) objects in free fall move in geodesics. Thus an orbiting satellite moves in the curve around the planet that is the geodesic for it given its velocity, etc. If it is in a circular orbit it does not gain or lose kinetic energy (ignoring orbital decay). If it is in any other orbit it gains and loses velocity and its kinetic and gravitational potential energy are constantly rebalanced. It is this latter process whose mechanism puzzles me.
Why does following a straight line in curved space turn potential energy into kinetic energy and vice-versa?
The quantum fields in the standard model each have energy. The gravitational metric field - what is its energy, that it can do these physical things? It is not the whole vacuum energy, as other fields and condensates have a contribution. Please regard that question as part of the whole question in this post. Presumably the gravitational metric field, or curved space-time, must have energy to be physical, and this might be key to its ability to accelerate bodies.
In General Relativity (as I understand it) objects in free fall move in geodesics. Thus an orbiting satellite moves in the curve around the planet that is the geodesic for it given its velocity, etc. If it is in a circular orbit it does not gain or lose kinetic energy (ignoring orbital decay). If it is in any other orbit it gains and loses velocity and its kinetic and gravitational potential energy are constantly rebalanced. It is this latter process whose mechanism puzzles me.
Why does following a straight line in curved space turn potential energy into kinetic energy and vice-versa?
The quantum fields in the standard model each have energy. The gravitational metric field - what is its energy, that it can do these physical things? It is not the whole vacuum energy, as other fields and condensates have a contribution. Please regard that question as part of the whole question in this post. Presumably the gravitational metric field, or curved space-time, must have energy to be physical, and this might be key to its ability to accelerate bodies.