The 'graviton picture': a Bohr model for gravitation on galactic scales?1.

Modified Newtonian dynamics (MOND) provides a successful description of stellar and galactic dynamics on almost all astronomical scales. A key feature of MOND is the transition function from Newtonian to modified dynamics, which corresponds to the empirical mass discrepancy-acceleration (MDA) relation. However, the functional form of the MDA relation does not follow from theory in a straightforward manner; in general, empirical MDA relations are inserted ad hoc into analyses of stellar dynamics. I revisit the possibility of gravity being mediated by massive virtual particles, gravitons. Under certain reasonable assumptions, the resulting 'graviton picture' implies a MDA relation that is equivalent to the - empirical - 'simple μ' function of MOND, which is in very good agreement with observations. I conclude that the 'graviton picture' offers a simple description of gravitation on galactic scales, potentially playing a role for gravitation analogous to the role played by Bohr's model for atomic physics. [ABSTRACT FROM AUTHOR]