A new perspective on galactic dynamics
  We derive the radial acceleration of stars in galaxies by using basic
features of thermodynamics, statistical mechanics and general relativity. We
assume that the "dark" component of the radial acceleration is originated from
the reaction of dark energy to the presence of baryonic matter. It can be also
explained as the macroscopic manifestation of a huge number of extremely soft
bosonic excitations of the dark energy medium with wavelength larger than the
size of the cosmological horizon, in thermal equilibrium with de Sitter
spacetime. Our formula agrees with the phenomenological relation proposed by
McGaugh et al. which, in turns, fits a large amount of observational data and
with the MOND theory. We also show that our formula appears as the weak field
limit of Einstein's general relativity sourced by an anisotropic fluid.
