Galaxy Collision 2D: Top-Down N-Body Merger

This 2D top-down companion to the 3D galaxy-collision simulator reimplements the same mechanic as a restricted N-body model: two galaxy cores orbit and fall toward each other under real mutual Newtonian gravity, while thousands of star particles in each disk feel the pull of both cores without pulling back, stretching into the tidal bridges and tails astronomers see in real merging galaxies. Adjust the mass ratio between the two galaxies, their approach speed, and the impact angle, then watch the live readouts track core separation, relative velocity and elapsed time as the encounter unfolds toward a merger or a fly-by.