# Does the curvature of SpaceTime Disprove gravity?

1. Jul 27, 2009

### TheIsland24

Obviously not. But I am confused on this. Newtons laws of gravity did not fit with Einsteins Relativity theories because Newton said that a change in matter of an object would cause a shift to be felt by others in the universe because of the change in gravity. This would mean that the movement/ change of the gravitons would be faster than the speed of light, which isn't possible in general relativity because light is standard/constant. In order to incorporate gravity into his theory, Einstein eventually created General Relativity which says that SpaceTime is curved. Objects attempting to move in straight lines in space follow this curvature. Was Einstein saying that this curvature creates the illusion of gravity, and thus gravity did not really exist? How did saying that Space and Time were curved solve the problem of gravity in terms of Relativity that I already mentioned? The only way I can see this problem being solved is if Einstein was saying gravity didnt actually exist ( it was just objects trying to follow straight lines but actually following curved lines). I know this isnt true because curved space and time is accepted today, as well as gravity. Could someone explain PLEASE!?

2. Jul 27, 2009

### Nabeshin

You are essentially correct.

If you want to think of Newton's theory of gravitation in terms of gravitons, then yes these gravitons did travel faster than the speed of light. In fact, they traveled infinitely fast because the gravitational interaction between bodies was propagated instantaneously in Newton's theory. As you say, instant transfer of information is forbidden in relativity, so this is a bit of a problem.

Einstein's theory of GR, in a sense, does say that gravity is a "fake" force. Einstein was saying that what we perceive as gravity as actually simply the product of mass warping space time and objects following their natural trajectories. It essentially replaces a traditional force (carrier particle, in the sense of the standard model) model of the gravitational interaction with a completely geometric model of gravity.

3. Jul 27, 2009

### TheIsland24

Thank you very much. How are both of these ideas accepted today? Obviously gravity is accepted as a force, but General Relativity is also accepted as a theory...doesnt add up in my mind.

4. Jul 27, 2009

### Fredrik

Staff Emeritus
See post #4 here. That thread was near the top of the first page when you created this one, so I'm surprised you didn't see it.