Hi D and all -

this from Physics Today

http://ptonline.aip.org/journals/doc/PHTOAD-ft/vol_60/iss_3/16_2.shtml

"In commenting on letters responding to his Einstein article (PHYSICS TODAY, November 2005, page 31, [ entitled "Einstein's Mistakes"-ab] and April 2006, page 10 "The Value of Einstein's Mistakes"), Steven Weinberg states that he "never understood what is so important physically about the possibility of torsion in differential geometry." He basically argues that torsion "is just a tensor" and could be treated like any additional tensor field in the context of general relativity.
In my opinion, however, a decisive point was overlooked. Torsion is not just a tensor, but rather a very specific tensor that is intrinsically related to the translation group, as was shown by Élie Cartan1 in 1923–24. In fact, in the Yang–Mills sense, it is the field strength of the translations. Torsion is related to translations and curvature to Lorentz rotations. As one consequence, torsion cracks an infinitesimal parallelogram in the spacetime continuum and gives rise to a closure failure described by a vector (in dislocation theory in solids in three dimensions, it is the Burgers vector)."

"The simplest gravitational theory with torsion, the Einstein–Cartan theory, is a viable one. Incidentally, torsion could be measured by the precession of nuclear spins, even though the effects are expected to be minute in the present-day cosmos."

Minute, except in the cases of magnetic vortexes produced by Tesla and H, etc...

and this from Physics Forums

http://www.physicsforums.com/archive/index.php/t-161053.html
"The fact that the mathematical form of the torsion tensor is similar to the form of the Maxwell field strength tensor tantalized Einstein for a good three years,1928-1931,in one of his schemes to connect gravitation and electricity geometrically.For that theory,visit Living Reviews In Relativity,Hubert Goenner's 'On The History of Unified Fied Theories'."

This is the form of the theory which influenced Kron. Did Einstein unify the fields with that "distant parallelism" where the EM(T) G vectors twist together? Some authors suggest he retracted it as he feared misuse, or it was retracted after PX, etc.... and we still have guys like Weinberg trivializing it.



best regards,

ab