| together with interstellar turbulence , gravitation is one key player in star formation . it acts both at galactic scales in the assembly of gas into dense clouds , and inside those structures for their collapse and the formation of pre - stellar cores . to understand to what extent the large scale dynamics govern the star formation activity of galaxies , we present hydrodynamical simulations in which we generalise the behaviour of gravity to make it differ from newtonian dynamics in the low acceleration regime . we focus on the extreme cases of interacting galaxies , and compare the evolution of galaxy pairs in the dark matter paradigm to that in the milgromian dynamics ( mond ) framework . following up on the seminal work by tiret & combes , this paper documents the first simulations of galaxy encounters in mond with a detailed eulerian hydrodynamical treatment of baryonic physics , including star formation and stellar feedback . we show that similar morphologies of the interacting systems can be produced by both the dark matter and mond formalisms , but require a much slower orbital velocity in the mond case . furthermore , we find that the star formation activity and history are significantly more extended in space and time in mond interactions , in particular in the tidal debris . such differences could be used as observational diagnostics and make interacting galaxies prime objects in the study of the nature of gravitation at galactic scales . gravitation galaxies : interactions galaxies : starburst stars : formation methods : numerical |