There's something I've always wonder about general relativity and what it has to say about the workings of physical laws. Here's a scenario:

 

You're sitting in a space pod and you push on the engine throttle cause the pod to accelerate forward. You feel the force of acceleration pushing you back against your seat. Now what general relativity says about this scenario is that you can look at it two ways: 1) that the pod is accelerating forward and it is the forward moving force of the seat against your back that you feel, or 2) that there is a gravitational field behind you and all objects of the universe fall under its influence, except you and your pod because the force of the rockets keep you in place.

 

So here's my question: How does general relativity explain the spontaneous existence of such a gravitational field, especially when there's no mass to sustain it? It would have to say that by pushing the engine throttle, not only do you egnite the engines, but you CAUSE a gravitational field to pop into existence. In other words, the laws of physics themselves would be subject to relativity (that is, what kind of physical laws exist in the universe is relative to your persective). What does GR say about this?

 

Gib

Non sequitur. An acceleration doesn't cause a gravitational field to come into existence. GR doesn't say that an acceleration is a gravitational field, it just says the effects are indistinguishable.

oooooh

Oh I'm sure there are alternate ways to look at it. "Nonsequitor" is kinda too harsh.

 

For example, at Usenet Relativity FAQ it gives one possible alternate view:

 

You may be bothered by the Big Coincidence: how come the uniform "gravitational" field happens to spring up just as Stella engages her thrusters? You might as well ask children on a merry-go-round why centrifugal force suddenly appears when the carnival operator cranks up the engine. There's a reason such forces have had to endure the derisive prefix "pseudo" in so many books.

And that site has a little more to say about it too. You could say, the pseudo G-field, the "fictitious force" facilitates the simplicity of using the accelerating entity's "stock-still-in-space" frame for all physical computations -- which may be expedient; or even poignant.