Colliding Galaxies

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This Demonstration simulates two colliding galaxies. Each star is initialized with a Keplerian initial velocity and circular orbit, affected only by the mass centers of the two galaxies and not by neighboring stars.


On the surface, this resembles the effects of a galaxy collision, but it is only a very rough first approximation. Much more computationally intensive simulations may take dark matter and interactions between stars into account. Even with the more complicated parameters ignored, this simulation can still provide a glimpse into how galaxies interact.


Contributed by: Jeff Bryant and Dale Horton (March 2011)
Based on a program by: Michael C. Schroeder and Neil F. Comins
Open content licensed under CC BY-NC-SA



For reference, each time unit represents 1.2 million years, one distance unit represents 500 parsecs, and one mass unit represents 20 billion solar masses. The target galaxy is fixed at 5 mass units.

The code used for this simulation is based on a program presented in M. C. Schroeder and N. F. Comins, "Galactic Collisions on Your Computer," Astronomy, 16(12), 1988 pp. 90–96.

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