General Relativity vs Geometrodynamics

mhob
Messages
14
Reaction score
1
What are the difference between Einstein's General Relativity and Wheeler's Geometrodynamics,or they are the same thing?
 
Physics news on Phys.org
They are the same thing, IMHO. I think Wheeler just coined the term Geometrodynamics to emphasize that in General Relativity the geometry of space-time is a dynamic entity.
 
Thanks.
 
I might be wrong, but I think geometrodynamics is not just a different name for general relativity. It was supposed to push the idea to the limit and geometrize all classical fields, may be even quantum, and give geometrical description of physical quantities such as charge. Hence the "charge without charge" and so on motto.
 
I asked a question here, probably over 15 years ago on entanglement and I appreciated the thoughtful answers I received back then. The intervening years haven't made me any more knowledgeable in physics, so forgive my naïveté ! If a have a piece of paper in an area of high gravity, lets say near a black hole, and I draw a triangle on this paper and 'measure' the angles of the triangle, will they add to 180 degrees? How about if I'm looking at this paper outside of the (reasonable)...
From $$0 = \delta(g^{\alpha\mu}g_{\mu\nu}) = g^{\alpha\mu} \delta g_{\mu\nu} + g_{\mu\nu} \delta g^{\alpha\mu}$$ we have $$g^{\alpha\mu} \delta g_{\mu\nu} = -g_{\mu\nu} \delta g^{\alpha\mu} \,\, . $$ Multiply both sides by ##g_{\alpha\beta}## to get $$\delta g_{\beta\nu} = -g_{\alpha\beta} g_{\mu\nu} \delta g^{\alpha\mu} \qquad(*)$$ (This is Dirac's eq. (26.9) in "GTR".) On the other hand, the variation ##\delta g^{\alpha\mu} = \bar{g}^{\alpha\mu} - g^{\alpha\mu}## should be a tensor...
Back
Top