Konstantinos D Kleidis
Technological Educational Institute of Central Macedonia, Greece
Title: On the nature of dark energy
Biography
Biography: Konstantinos D Kleidis
Abstract
During the last 20 years, a continuously growing list of observational data has verified the existence of a distributed energy component in the Universe, i.e., one that does not cluster at any scale. Reflecting our ignorance on its exact nature, this new constituent of the cosmic matter-energy content was dubbed dark energy (DE). The determination of DE’s exact nature has become one of the biggest problems in theoretical physics and cosmology; consequently, (too) many models have been proposed. Here, we review a series of recent theoretical results, regarding a conventional approach to the DE concept. In short, by compromising General Relativity and Thermodynamics at cosmo-logical scales, we end up with a model without any extra (dark) energy component. In this model, the Universe is filled with a perfect fluid of self-interacting dark matter (DM), the volume elements of which perform polytropic flows. Consequently, the energy of this fluid’s internal motions should also be considered as a source of the universal gravitational field. As we demonstrate, this form of energy can compensate for the extra (dark) energy needed to compromise spatial flatness in an accelerating Universe. Furthermore, in this case, there is no disagreement between observations and the theoretical prediction of the (distant) supernovae (SNe) Type Ia distribution. In fact, the cosmological model with matter content in the form of a polytropic-DM fluid can interpret to high accuracy any observational data associated with the recent history of Universe expansion, thus arising as a mighty contestant for a realistic DE model.