If one introduces the prescription of space-time averaging of the integrals, one finds that the definitions of Landau-Lifshitz and Papapetrou-Gupta yield (equal) coordinate-invariant results. In a frame containing coordinate waves they are ambiguous, since their value depends on the location of the surface at infinity (unlike the case where gμν,α vanishes faster than 1/r). This permits "coordinate waves." It is found that none of the expressions giving the energy as a two-dimensional surface integral are invariant within this class. We use the boundary conditions that gμν approaches the Lorentz metric as 1/r, but allow gμν,α to vanish as slowly as 1/r. The invariance of various definitions proposed for the energy and momentum of the gravitational field is examined. The physical meaning of the electromagnetic field properties is also derived from the graphs of electric and magnetic components against x-axis coordinate and mass density respectively. The calculations are performed with the Mathematica and Maple programs which have attached the GrTensor platform. Supposing the private case of an electromagnetic field we have suggested on establish the concrete dependence on the space-temporal coordinates of the electric and magnetic fields.
In this paper we have continued the studies from our previous works about the electromagnetic field in a rotating universe. The existence of such a small rotation, when extrapolated to the early stages of the universe, could have played a major role in the dynamics of the early universe, and possibility also in the processes involving galaxy formation. Hence the possibility that the universe itself could be rotating has attracted a lot of attention. Most of the astronomical objects in the universe (planets, stars or galaxies) have some form of rotation (differential or uniform).
0 kommentar(er)
