Abstract Details

Name: Arun Kenath
Affiliation: Christ University, Bangalore
Conference ID: ASI2017_1242
Title : Alternate Models to Dark Matter and Dark Energy
Authors and Co-Authors : S B Gudennavar (Department of Physics, Christ University, Bengaluru-560029, Karnataka, India) C Sivaram (Indian Institute of Astrophysics, Bengaluru-560 034, Karnataka, India)
Abstract Type : Poster
Abstract Category : General Relativity and Cosmology
Abstract : The nature of dark matter and dark energy which is supposed to constitute about ninety five percent of the energy density of the universe is still a mystery. There is no shortage of ideas regarding the nature of both. And there are several experiments that are currently ongoing to detect the postulated dark matter particles. Some of these experiments have been running for many a year and has yielded no positive results so far. Only lower and lower limits for their masses are set with these experiments. But if future experiments still do not give any clue about the existence of dark matter, one may have to consider looking for alternate theories. Keeping in mind the negative results in some of the ongoing detection experiments, here we propose the possible alternatives to both dark matter and dark energy. The alternate models include Modification of Newtonian Dynamics (MOND) and Modification of Newtonian Gravity (which has supposedly proved more successful than dark matter model, in explaining flat rotation curves of galaxies, but does not work for large galaxy clusters, where some dark matter is required anyway), Tensor–Vector–Scalar Theory (which was developed as a relativistic generalisation of MOND, and is derived from the action principle. In the weak-field approximation, static solution, this theory gives the MOND acceleration formula. This theory can account for the gravitational lensing, since it is a relativistic theory), and Modification of Einstein-Hilbert Action. The two poplar theoretical concepts to resolve the apparent inconsistency of Newtonian dynamics over galactic scales and beyond is assumption of ubiquitous presence of dark matter and secondly the assumption that Newtonian gravitational law or dynamics requires modification. Here we also look at the possibility of differentiating MOND from Newtonian dark matter theory. Theoretical problems with scenarios like fine tuning, presence of a lambda term with just the required value at present epoch etc. have also led to suggestions that general relativity be modified in such a way that leads to observed accelerated expansion. We also look at the possibility of observationally distinguishing the two alternative scenarios.