Natural Science Forum / Physics / Research / November 2007

Both GPS and Grav Probe A.

Einstein's elevator Gedankenexperiment,
Jahrbuch der Radioaktivität u. Electronik 4 411 (1907)
"The Collected Papers of Albert Einstein," Vol. 2, English
translation, A. Beck, trans. (Princeton University Press: Princeton,
NJ, 1989) p. 252.

GPS.  Four cesium or three rubidium atomic clocks/satellite and 31
satellites as of September 2007, all in vacuum free fall.  Is that
enough?  GPS cesium and rubidium atomic clock frequencies can be
corrected to 2x10^(-13).  

General relativity predicts GPS orbital clocks tick faster (out of the
gravitational well) by ~45.9 microseconds/sidereal day. Special
relativity predicts they tick slower by ~7.2 microseconds/day.  The
combined divergence is 4.465 parts in 10^10.  Satellite frequency
ground standard has a rate offset to 10.22999999543 MHz instead of
10.23 MHz for obital correction.

The elevator Gedankenexperiment assumes space is homogeneous and
isotropic.  A chiral vacuum background would leave all prior
observations unscathed, however...  Single crystal quarz
hydrothermally grown in crystallographic space groups P3(1)21
(right-handed screw axes) and P3(2)21 (leftt-handed screw axes) would
violate the Equivalence Principle.  P3(1)21 would be the big outlier.

If the vacuum is a left foot the atomic mass distributions of the two
enantiomorphic space groups would be opposite shoes.  They would
statically insert with different energies.  They would locally vacuum
free fall along *divergent* minimum action trajectories.

Put on two left shoes and walk with your eyes closed.  Do you walk a
straight line?

Sure. The GPS satellite clocks are in freefall. And so was Gravity Probe A:
    Vessot et al., “A Test of the Equivalence Principle Using a
    Space-borne Clock”, Gel. Rel. Grav., 10, (1979) 181–204. “Test
    of Relativistic Gravitation with a Space borne Hydrogen Maser”,
    Phys. Rev. Lett. 45 2081–2084.

They flew a hydrogen maser in a Scout rocket up into space and back (not
recovered). Gravitational effects are important, as are the velocity
effects of SR.

Tom Roberts