MOND with or without dark matter
  In our current cosmological model, the main constituents of the Universe are
dark matter and dark energy, whose nature is unknown, and for which there is no
place in the standard model of particle physics. How to include dark matter and
dark energy in the set of fundamental laws? All observations can as well be
explained either within the frame of general relativity, by adding unknown
components in the Universe, or by modifying fundamentally the theory. Would not
the last possibility be more simple? This is the case of the MOND hypothesis
(for MOdified Newtonian Dynamics) proposed by Milgrom in 1983, which is quite
successfull to describe the kinematics and dynamics of galaxies. It might
however also be possible to reach the same success through a new kind of
matter, dipolar dark matter, keeping general relativity for the law of gravity.
