"Gravity Force" outmoded concept
The analogy of gravity force with electrical force is not very good. However, take a large flat charged conducting plate.
http://www.math.uni-bremen.de/~justen/Forschung/ie_condenser.jpg
Near its center the electric force field is approximately uniform in analogy with a uniform gravity force field in Newton's picture. Above picture is for a condenser with oppositely charge plates that give similar effect. I am talking about the RED region.
That is there is a finite region of space in which approximately from Gauss's law
Grad^2V ~ source density
doing integrals and using symmetry
V(Coulomb) ~ Ez
z is normal distance to plate
the force per unit mass on a test particle charge q and mass m is
a = -(q/m)dV/dz = - (q/m)E
E ~ spatially uniform in limited region
In Newtonian gravity from potential theory there is a similar Gauss law
V(Newton) ~ gz
a = g
Approximately uniform
What this means in Einstein's theory is the following.
The approximate metric can be written as (c = 1)
ds^2 ~ -(1 - gz)dt^2 + (1 - gz)^-1dz^2 + dx^2 + dy^2
gz << 1
For the rest "shell" LNIF hovering observers
dz(LNIF shell) = dz/(1 - gz)^1/2 ~ dz(1 + gz/2)
dt(LNIF shell) = dt(1 - gz)^1/2 ~ dt(1 - gz/2)
The z distance between stationary nongeodesic shell observers is larger than the "book keeping" amount (if there were no source) by gz/2
Note the approximation gz << 1.
i.e. gz/c^2 << 1
The gravity red shift is for a receiver far away and sender at z is for frequency of signal f
f(receiver) ~ f(sender)(1 - gz/2c^2)
only from that limited region.
The important part of the connection field here is
c^2{^z00} ~ g
but that is only in the non-geodesic SHELL FRAME.
It's not frame-invariant.
Note in electricity
The electromagnetic force is a tensor
f^u = (q/m)F^uvV^v
But in gravity in Einstein's theory
the Newtonian "gravity force" is not a tensor
g ~ c^2{z,00}
The shell LNIF observers must provide a non-gravity force to keep at fixed z in the above problem
This is CONTINGENT - not INTRINSIC.
There is no intrinsic gravity force in Einstein's theory. All gravity force is 100% inertial depending on arbitrary choice of the non-geodesic needing a non-gravity force to exist. The curvature field is intrinsic i.e. a tensor, but it is geodesic deviation independent of arbitrary choices of non-geodesics from non-gravity forces. There is never any "g-force" on a massive test particle on a timelike geodesic in curved space-time. The test particle acceleration on a geodesic is zero. The intrinsic classical geometrodynamic field is fully determined by the geodesic structure. Intrinsic curvature is "geodesic deviation". All non-geodesics are contingent not necessary and they require external non-gravity forces to create. Null event horizons are barriers (one-way membranes) to all timelike worldlines whether geodesic or nongeodesic). Spacelike worldlines pass through event horizons but on-mass-shell tachyons usually signal a vacuum ODLRO instability and are not themselves stable. Post-quantum signal nonlocality observed in the CIA SRI experiments of Puthoff & Targ and confirmed in other experiments
http://www.signonsandiego.com/news/science/20060622-9999-lz1c22cause.html
do not change the above considerations. That is, non-light signal based nonlocal C^3 will not provide "absolute simultaneity". Classical GR geometrodynamics is not affected by post-quantum signal nonlocality that is a mental process confined to living conscious matter far from thermal equilibrium.
http://xxx.lanl.gov/abs/quant-ph/0203049
Tuesday, August 22, 2006
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