- #1

- 60

- 1

## Main Question or Discussion Point

Why is it that the EM force can't be modeled on spatio-temporal curvature the way gravity can be?

- I
- Thread starter Ontophobe
- Start date

- #1

- 60

- 1

Why is it that the EM force can't be modeled on spatio-temporal curvature the way gravity can be?

- #2

- 30,135

- 9,297

In the case of gravity, by contrast, all three objects would stay together (we start them at the same point in space so tidal gravity won't separate them). Heuristically, this is because gravity acts on the "mass to mass ratio", not the charge to mass ratio, and the mass to mass ratio is the same for all objects. (Usually this is described as inertial mass being the same as gravitational mass.) But observationally, the key fact is that gravity obeys the equivalence principle, whereas the EM force does not.

- #3

- 60

- 1

- #4

- 30,135

- 9,297

@Ontophobe , you're quite welcome.

- #5

- 536

- 35

Yes, it can! See Kaluza-Klein theory.Why is it that the EM force can't be modeled on spatio-temporal curvature the way gravity can be?

- #6

- 30,135

- 9,297

The curvature that models electromagnetism in Kaluza-Klein theory is not spatio-temporal; it's in a dimension other than the 4 spacetime dimensions. So it's not relevant to the OP's question.See Kaluza-Klein theory.

- Last Post

- Replies
- 10

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 3K

- Last Post

- Replies
- 3

- Views
- 2K

- Last Post

- Replies
- 3

- Views
- 2K

- Replies
- 8

- Views
- 4K

- Last Post

- Replies
- 4

- Views
- 2K

- Last Post

- Replies
- 55

- Views
- 4K

- Last Post

- Replies
- 23

- Views
- 5K

- Replies
- 1

- Views
- 1K

- Last Post

- Replies
- 10

- Views
- 6K