The Colliding Galaxies Model is an implementation of Alar and Juri Toomres' 1972 super computer model showing the formation of galactic bridges and tails under the assumption that galactic cores are point masses and that one galactic core is surrounded by 2D concentric rings of orbiting stars.  The model assumes is that the stars (test particles) orbiting the galactic cores are non-interacting.  When the two galaxies pass one another, tidal forces deform the star distribution into classic tidal features.  Our EJS model reproduces this result showing that there is a long curving tail and that only the outermost ring of stars is affected by its companion galaxy. A thin bridge is also formed and some of the stars are captured by the companion galactic core.

The Colliding Galaxies Model was created using the Easy Java Simulations (EJS) modeling tool.  It is distributed as a ready-to-run (compiled) Java archive.  Double clicking the ejs_mech_orbits_CollidingGalaxies.jar file will run the program if Java is installed.

Please note that this resource requires at least version 1.5 of Java.