The Gravity-GR Paradox

[HydrogenBond]

Gravity is expressed using GR. But based on some simple observations this does not appear to tell the whole story. Let me give a simple mind experiment. Say we had a rubber ball and placed a heavy bolder onto the ball. The compression of the ball is due to gravity acting. If the bolder was already there, and we only lifted up its edge and added the mass of a rubber ball beneath it, the local GR may change only slightly. If the ball's final volume is cut in half, GR alone does not explain this. But it is a real experiment we can prove.

Another way to look at it is to compare SR. In this case, space-time contracts. But within that reference, the proportional geometry of the rubber ball will be maintained. With GR, although it also shows a space-time affect, proportional geometry gets tighter allowing the ball to compress. I would have conclude the space-time affects of SR and GR are not the same. It appears like SR space-time is based on contraction and GR on expansion.

Let me explain space-time expansion. We start with the ball on an x,y,z space coordinate system, so it begins within the volume confined by (1,1,1). With the GR space-time expansion, the coordinate system is expanded with the ball staying the same. So now it appears to be occupying the volume confined to (0.5, 0.5,0.5). This new geometry is now compressed relative to the new coordinate system. If it was space-time contraction, the coordinate system would cause it to be heading toward (2,2,2).

[john l. mccowen]

what holds the seed of light to the speed of it self ?

[LaurieAG]

Originally Posted by HydrogenBond

I would have conclude the space-time affects of SR and GR are not the same. It appears like SR space-time is based on contraction and GR on expansion.

Hi HydrogenBond,

It's like one is internally relative and the other is externally relative?

[Pyrotex]

Hello HB,
SR is "special" for a reason. It doesn't explain gravity at all, but explains what we will observe when we see objects traveling at speeds near c. (or WE are traveling at speeds near c). In SR, gravity is simply treated as an accelleration like any other accelleration. (say, from a rocket engine).

GR explains gravity.

[UncleAl]

Those who know nothing should post in kind. GR is covariant - no coordinate background. SR is a subset of GR with Newton's G set to zero. There is no gravitation in SR. There are no paradoxes or contradictions within, nor are there any empirical counterexamples to either SR or GR.

Experimental Basis of Special Relativity
Experimental constraints on Special Relativity

The Confrontation between General Relativity and Experiment
[gr-qc/0311039] 35 Years of Testing Relativistic Gravity: Where do we go from here?
Experimental constraints on General Relativity

http://tycho.usno.navy.mil/ptti/ptti2002/paper20.pdf
Nature 425 374 (2003)
http://www.eftaylor.com/pub/projecta.pdf
http://www.public.asu.edu/~rjjacob/Lecture16.pdf
Relativity in the Global Positioning System
Relativity in the GPS system

Newton was wrong,
[gr-qc/9909014] Kinetic Energy and the Equivalence Principle
Amer. J. Phys. 71 770 (2003)
Phys. Rev. Lett. 92 121101 (2004)
Nature 425 374-376 (2003).
The Confrontation between General Relativity and Experiment
Section 3.4.1, Figure 5

[HydrogenBond]

All I was saying is gravity causes physical compression some of which can not be explained with GR alone. Try this; take a cube of foam. We will label the z- axis on the outside of the cube from 0 to 4CM. Place the boulder on top and the coordinate system gets crunched to say 1CM, with the 4CM mark now measured at 1CM. GR does does not explain this part of gravity. All that we attribute to GR=gravity in a star is not the entire effect. In one respect classical gravity is an approximation for GR and in the other way GR is only an approximation for this classical affect.

[Pyrotex]

Originally Posted by HydrogenBond

All I was saying is gravity causes physical compression some of which can not be explained with GR alone. ...

Hmmm... Well... A lot of things can cause compression which "cannot be explained by GR alone". I don't see the problem.

My garlic press can cause compression. GR can't explain that.
My auto engine can cause compression. GR can't explain that.
A sausage packer can cause compression. GR can't explain that.
A tennis ball in a vice can cause compression. GR can't explain that.

Could you rephrase you question or problem? :/

[Jay-qu]

I agree with Pyro, your situation of compression is a force that has pulled the ball down and compressed another - this has nothing to do with space time compression or expansion.