On the Big Bounce Singularity of a Simple 5D Cosmological Model

The big bounce singularity of a simple 5D cosmological model is studied. Contrary to the standard big bang space-time singularity, this big bounce singularity is found to be an event horizon at which the scale factor and the mass density of the universe are finite, while the pressure undergoes a sudden transition from negative infinity to positive infinity. By using coordinate transformation it is also shown that before the bounce the universe contracts deflationary, and the universe has been existed, according to the proper-time, for an infinitely long time. PACS: 04.50.+h, 98.80.Bp The inflationary cosmology can resolve three important problems of the standard big bang models: the galaxy formation problem, the horizon problem, and the flatness problem. However, there are other deep questions of cosmology which inflation does not resolve: What occurred at the initial singularity? Does time exists before the big bang? These issues have been popular in cosmology for a long time. Tolman firstly discussed an oscillating cosmological model within the framework of general relativity. He pointed out that the main difficulty of such an oscillating model is that the universe e-mail: [email protected]