Big Bang nucleosynthesis provides a unique probe of the early evolution of the Universe and a crucial test of the consistency of the standard hot Big Bang cosmological model. Although the primordial abundances of 2H, 3He, 4He, and 7Li inferred from current observational data are in agreement with those predicted by Big Bang nucleosynthesis, recent analysis has severely restricted the consistent...

For all the interesting possible phenomena which might have occurred during the early universe, there are really only two observational cosmological probes. Of those two, the only probe during the relevant radiation dominated epoch is the yield of light elements during the epoch of big bang nucleosynthesis. The synthesis of light elements occurs in the temperature regime from 108 to 1010 K and ...

In this paper we compare the expressiveness of the Task Oriented Programming iTask approach of specifying interactive GUI applications with ObjectIO and Racket big-bang . ObjectIO is representative for the large class of traditional desktop widget based toolkits aiming to provide the programmer with full access the underlying GUI toolkit in a functional style. In contrast, the Racket big-bang a...

During its hot, dense, early evolution the Universe was a primordial nuclear reactor, synthesizing the light nuclides D, He, He and Li in the first thousand seconds. The presently observed abundances of these relic nuclides provide a unique window on the early Universe. The implications of current observations for cosmology (the universal density of nucleons) and for particle physics (new parti...

String theory can (in principle) describe gravity at all curvature scales, and can be applied to cosmology to look back in time beyond the Planck epoch. The duality symmetries of string theory suggest a cosmological picture in which the imprint of a primordial, pre-big bang phase could still be accessible to present observations. The predictive power of such a scenario relies, however, on our a...

The evolution of the rotational inhomogeneities is investigated in the specific framework of four-dimensional pre-big bang models. While minimal (dilaton-driven) scenarios do not lead to rotational fluctuations, in the case of non-minimal (string-driven) models, fluid sources are present in the pre-big bang phase. The rotational modes of the geometry, coupled to the divergenceless part of the v...

A brief review is given to the fundamental difficulties facing the Big Bang Theory, with the emphases on the geocentric nature, the extreme violation of the conservation laws of mass and energy, the violation of Maxwell’s velocity distribution, the horizon problem, the extreme instability and the dark matter problem. The historical alternatives and their problems are reviewed. The DET is then p...

The existence of stars and galaxies reqires cosmological models with an inhomogeneous matter and radiation distribution. But in these models the initial singularity surface t0(r) is in general homogeneous (independent of r). In this second paper of a series devoted to an inhomogeneous Big Bang singularity, we investigate the cosmic microwave background radiation (CMBR) dipole. A special Tolman-...

The primordial abundances of deuterium, helium, and lithium probe the baryon density of the universe only a few minutes after the Big Bang. Of these relics from the early universe, deuterium is the baryometer of choice. After reviewing the current observational status (a moving target!), the BBN baryon density is derived and compared to independent estimates of the baryon density several hundre...

We analyze a general mechanism for producing a nearly scale-invariant spectrum of cosmological curvature perturbations during a contracting phase preceding a big bang, that can be entirely described using 4d effective field theory. The mechanism, based on first producing entropic perturbations and then converting them to curvature perturbations, can be naturally incorporated in cyclic and ekpyr...