Some Of Mond, Gundlach Says With Entropy Gravitational Theory Research

An interesting alternative to dark matter approach in galaxies is the theory of Modified Newtonian Dynamics (MOND), proposed by Milgrom. However, as a hypothesis at a phenomenological level, its initial form seems can not describe the universe greatly. A lot of non-relativistic and relativistic MOND theories have been proposed.The acceleration of cosmological scale is about 10-10m/s2. Following the Newtonian cosmology, we try to give the MOND cosmological equations. It is found that these equations are dependent of the proper coordinate, showing that such an attempt is unlikely reasonable. If we propose that a0=a0(r)=A0r, we can also derive reliable cosmological equations.In the framework of relativistic MOND theory (TeVeS), we show that a late time background ACDM cosmology can be attained by choosing a specific function F(u) that also meets the requirement for the existence of Newtonian and MOND limits. We investigate the dynamics of the scalar fieldφunder our chosen F(μ), where the whole system reduces to ACDM cosmology.Recently, Verlinde made a new explain of the gravity:The gravity is not a fundamental force, but an entropic force caused by the changes in the information associated with the position of the bodies. Gao proposed that the equipartition law of energy can not be held in the limit of very low acceleration. Following the work of Gao, we found that the Debye function of one dimension can explain the MOND and the formula a0～cH0. Using the modified Raychaudhuri equation, we can get the modified Friedmann equations. With some approximations, we found these modified equations could explain the accelerating universe. If we define the net temperature of the Unrch formula in inertial and uninertial system as the entropic force, we can explain the MOND. By use of dynamical spacetime, we can derive the cosmological equations directly.