Sunday, September 17, 2006

The measurement is still in the range of first order parametrized post-Newtonian accuracy. What the Donkey Kong that means is that these are the coefficients to the metric that are being tested:

dtaU^2 = (1 - 2 GM/c^2 R + 2 (GM/c^2 R)^2) dt^2

- (1 + 2 GM/c^2 R) dR^2/c^2

- R^2/c^2 dtheta^2

- R^2/c^2 sin^2 theta dphi^2

It is the 5 integers there (1, -2, +2, -1, -2) that are confirmed by this experiment. That is NOT NEWS, because it is not new. Shapiro got the same results. What would be news is if the experiment got to second order parameterized post Newtonian accuracy. I asked Prof. Clifford Will an expert on experimental tests of GR when where the data hunters going to gather that data. He said he knew of no one even discussing it. The reason is that the data must for 2nd order PPN effects must be a million fold more accurate, so we need data that is 99.99995% accurate.

I care a lot about 2nd order PPN tests, since that is were my proposal to unify gravity and EM using a 4D wave equation differs. GR says the metric should go here:

GR:

dtaU^2 = (1 - 2 GM/c^2 R + 2 (GM/c^2 R)^2 -3/2 (GM/c^2 R)^3) dt^2

- (1 + 2 GM/c^2 R + 3/2 (GM/c^2 R)^2) dR^2/c^2

- R^2/c^2 dtheta^2

- R^2/c^2 sin^2 theta dphi^2

GEM (gravity and EM):

dtaU^2 = (1 - 2 GM/c^2 R + 2 (GM/c^2 R)^2 -4/3 (GM/c^2 R)^3) dt^2

- (1 + 2 GM/c^2 R + 2 (GM/c^2 R)^2) dR^2/c^2

- R^2/c^2 dtheta^2

- R^2/c^2 sin^2 theta dphi^2

At first order PPN accuracy, the coefficients (1, -2, 2, -1, -2) are the same. At second order, they are different. That's the data I need. I'll probably be dead before it shows up.

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## Not good enough for me (Score:4, Funny)