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You can't create a similar transformation for an electric field under which the motion of a proton, electron, muon etc are all straight lines. The indicator th

by caf 6y ago

You can't create a similar transformation for an electric field under which the motion of a proton, electron, muon etc are all straight lines. The indicator that gravity is special is the fact that 'inertial mass' and 'gravitational mass' are the same thing.

nsonha 6y ago
> gravity is special 'inertial mass' and 'gravitational mass' are the same thing. That's undecidable and gravity is not special in that way https://physics.stackexchange.com/questions/390540/what-is-the-relationship-between-gravity-and-inertia https://physics.stackexchange.com/questions/390540/what-is-t... > the gravitational field and acceleration are inductive pairs (similar to the electromagnetic field and electric current.)
- caf 6y ago
  That's undecidable and gravity is not special in that way How so? You can have different electric charge to inertial mass ratios, but that is not so for gravitational mass to inertial mass.
  - ars 6y ago
    Gravitational attraction is a function of both objects, so the force between them is not a constant, same as for the electron. Also, what if you have a charge so high that the electrical-escape velocity exceeds the speed of light? A strange kind of black hole? I ask these things because I do not understand why gravity is called "not a force", while electromagnetism is, when I see no real difference between how particles act.
    - caf 6y ago
      Gravitational attraction is a function of both objects, so the force between them is not a constant, same as for the electron. The way that varies is always in proportion to the object's inertial mass though, which has the result that the path traced by an any object with the same starting position and velocity in a given gravitational field is going to be the same. Contrast this with charge, which can vary independently of inertial mass. This has the result that the paths traced by objects with the same starting position and velocity in a given electrical field will vary. This also means there is no fixed "electrical escape velocity". More massive objects with the same charge can escape with a lower velocity.
  - nsonha 6y ago
    the link mentions that it's not proven that intertial mass and gravitational mass are the same, they are related. If gravitation mass contributes to the majority of intertial mass it would look like they're the same. But let's just say they are the same, then gravity and "spacial" inertia are intertwined. Gravity is only special if intertia is also considered special. Inertia seems special because it's explainable in terms of motion in space. There might be other kinds of motion in other dimensions that could explain the randomness of quantum space.

by caf 6y ago

nsonha 6y ago

> gravity is special 'inertial mass' and 'gravitational mass' are the same thing. That's undecidable and gravity is not special in that way https://physics.stackexchange.com/questions/390540/what-is-the-relationship-between-gravity-and-inertia https://physics.stackexchange.com/questions/390540/what-is-t... > the gravitational field and acceleration are inductive pairs (similar to the electromagnetic field and electric current.)

caf 6y ago
That's undecidable and gravity is not special in that way How so? You can have different electric charge to inertial mass ratios, but that is not so for gravitational mass to inertial mass.
- ars 6y ago
  Gravitational attraction is a function of both objects, so the force between them is not a constant, same as for the electron. Also, what if you have a charge so high that the electrical-escape velocity exceeds the speed of light? A strange kind of black hole? I ask these things because I do not understand why gravity is called "not a force", while electromagnetism is, when I see no real difference between how particles act.
  - caf 6y ago
    Gravitational attraction is a function of both objects, so the force between them is not a constant, same as for the electron. The way that varies is always in proportion to the object's inertial mass though, which has the result that the path traced by an any object with the same starting position and velocity in a given gravitational field is going to be the same. Contrast this with charge, which can vary independently of inertial mass. This has the result that the paths traced by objects with the same starting position and velocity in a given electrical field will vary. This also means there is no fixed "electrical escape velocity". More massive objects with the same charge can escape with a lower velocity.
- nsonha 6y ago
  the link mentions that it's not proven that intertial mass and gravitational mass are the same, they are related. If gravitation mass contributes to the majority of intertial mass it would look like they're the same. But let's just say they are the same, then gravity and "spacial" inertia are intertwined. Gravity is only special if intertia is also considered special. Inertia seems special because it's explainable in terms of motion in space. There might be other kinds of motion in other dimensions that could explain the randomness of quantum space.