jim stasheff wrote:
Robert J. MacG. Dawson wrote:
And, as you know, there are still scales, almost a century later, on which its predictions are unsatisfactory.
For us ignorant of these, please explicate.
(1) At the very small scale, nobody has really managed to unify quantum mechanics (which is as thoroughly tested on its home turf as relativity is on its own) with general relativity. QM works astonishingly well on the atomic scale, GR works astonishingly well on the astronomical scale, but there is a big gap, "in which we live", in which neither is particularly evident and classical Newtonian mechanics works pretty well for most purposes. (2) At very large scales there is some question as to whether additional forces, not predicted by general relativity, are needed to explain some cosmological observations. This is more speculative, but a lot of physicists seem to think *something* needs to be done. -Robert