Gamma-Ray Bursts have been observed out to very high redshifts and provide time measures that are directly related to intrinsic time scales of the burst. Einstein’s theory of relativity is quite definite that if the universe is expanding then the observed duration of these measures will increase with redshift. Thus gamma-ray burst measures should show a time dilation proportional to redshift. A...

From the axiom of the unrestricted repeatability of all experiments, Bondi and Gold (also Hoyle) argued that the universe is in a stable, selfperpetuating equilibrium state. Their reasoning extends the usual cosmological principle to the perfect cosmological principle in which the universe looks the same from any location at any time. By itself, the perfect cosmological principle predicts the u...

The features, however, include the phenomena of red-shifts whose significance is still uncertain. Alternative interpretations are possible, and, while they introduce only minor differences in the picture of the observable region, they lead to totally different conceptions of the universe itself. One conception, at the moment, seems less plausible than the other, but this dubious world, the expa...

Analog gravity models of general relativity seem promising routes to providing laboratory tests of the foundation of quantum field theory in curved space-time. In contrast to general relativity, where geometry of a spacetime is determined by the Einstein equations, in analog models geometry and evolution of analog spacetime are determined by the equations of fluid mechanics. In this paper we st...

A large class of cosmological solutions (of the Einstein equations) in string theory, in the presence of Maxwell fields, is obtained by O(d, d) transformations of simple backgrounds with d toroidal isometries. In all the examples in which we find a (closed) expanding universe, such that the universe admits a smooth, complete initial value hypersurface, a naked singularity may form only at the t...