Where Has All the Mass-Energy Gone In General Relativity?

Einstein's general relativity geometrizes the gravitational field.  Since it is no longer a field of force how can it contain, no less conserve, mass-energy? As long as we are working in Euclidean space, conservation is expressed as the vanishing of a divergence. Only for Cartesian components of Euclidean space are the components of a tensor independent of the space point to which the tensor is connected to. This is no longer true for curvilinear coordinates even in Euclidean space, let alone for non Euclidean geometries. 

Does Unruh Radiation Take on Einstein's Equivalence Principle?

The perennial question as to whether a charge in a uniform gravitational field would radiate has seen its comeback many times. Looking at gravity as a force from the special relativitic viewpoint it would appear that the answer is "yes", but considering gravity as geometry from a general relativistic perspective one would be or inclined to say "no", which is what Bondi and Gold claimed. 

Deterministic Laws are Not Governed by Statistical Principles: There is no such thing as Entropic Gravity

In a New York Times science article entitled "A scientist takes on gravity"  (July 12th,  2010) Verlinde claims "that gravity is a consequence of the venerable laws of thermodynamics which describe the behavior of heat and gases."  Continuing we read "gravity is simply a byproduct of nature's propensity to maximize disorder." The analogy with 'hair fizzles'  couldn't be more adapt: it actually makes your hair want to stand up straight! 

Mustering the Courage to Cross the Schwarzschild Radius

Even before the appearance of Einstein's definitive paper on the General Theory of Relativity, Schwarzschild solved Einstein's equations on the assumptions that the space was empty, and that light rays could arrive and depart from a central point mass. Furthermore, it was assumed to be differentiable everywhere.

Can Kepler's Third Law be used to Derive the Schwarzschild Metric?

In a recently published book, "Reflections on Relativity",  Kevin Brown (which  has been on the internet for several years) derives the Schwarzschild metric from Kepler's third law without recognizing that it violates  Kepler's second law. In fact, the violation of Kepler's second law is necessary in order to derive the deflection of light about a massive  body and the  precession of elliptical orbits.