> > I think -- I may be in error here -- that you may be confusing Einstein's Theory of Special Relativity with his General Theory. Special Relativity is an extension of Quantum Mechanics and is the physics of the very small; it describes the interaction of matter by the 3 forces of electromagnetism, strong nuclear, and weak nuclear forces. On the other hand, General Relativity extends Newtonian physics by describing gravitational effects. This is what you mean by the motion of large celestial bodies. It is a large-scale physics that explains the perturbations of planetary motion as well as the bending of light (quanta) by gravity, and it is confirmed by astronomical observations.
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> Hmm. You might be right, but I was always taught that SR reduces to "slow" (ie Newtonian) kinematics when v

I think you got cut off here. :-)


> > The reason why I said "the twain do not meet" is that I understood the math to be mutually incompatible. For Quantum Field Theory to work, the gravitational constant must be assumed insignificant (i.e., G=0). And for General Relativity in the Newtonian model to work, Planck's constant must be set to zero (h=0). Obviously you can't have both set to zero at the same time. :-) Hence, the conflict.
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> > Wolfspirit
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> h=0? As far as I know, both the strong and weak forces require h to be some small but nonzero number. (Anyway, we found h in a lab project last month. Trust me, it's not zero :-))

I didn't say it was, there. If you're looking at things at the Quantum level, in terms of strong and weak nuclear forces, then evidently you don't *want* h to be zero. Planck's constant, by definition, defines the emission of electromagnetic radiation in *discrete* chunks of energy -- those are quanta. I said that when you're looking at things (kinematics?) on the macroscopic level where gravity is in force, then you don't *need* to think of energy in terms of discrete quanta, but you *do* need G to be available. So effectively, h can be ignored AT THAT POINT, in the macroscopic model.


> Also, I don't think any physicist is trying to reconcile GE with classical mechanics. Dirac formulated a quantum theory in the 60's that was SE-compatible; I think the challenge now is to figure out how gravity is quantized.

Einstein's General Theory already did the reconcilation. I don't know exactly what you mean by GE and SE-compatible, unless you mean General and Special Einstein etc.; the several courses I took in quantum theory were over a decade ago. But I can quote physicist Karl Lloyd in some more recent notes on the subject:

"The quest to find a single unifying theory describing the Universe can therefore be approached in two ways: one can try to generalise the present flat-space formulation of Quantum Field Theory to one which describes quantum fields in the presence of mass-energy, i.e., in curved space -- or one can try to introduce quantum 'fuzziness' into spacetime to formulate a QFT version of gravity: 'Quantum Gravity'.
This latter approach is the one which has seen the most intensive research -- indeed, as a Theory of Everything, it is metaphysically the most satisfactory as it places all four fundamental forces of nature on an equal footing. Crucially, it also says that spacetime itself is only an approximate concept. One should then expect that any 'Theory of Everything' should contain General Relativity only as an approximation, as h goes to zero, and will doubtless contain many new and strange phenomena not observed in the macroscopic world."