🌌 Galaxy Collision Lab (2D): Two-Core Gravitational Merger

This 2D companion keeps the same gravity model as the 3D scene — two massive cores pulling on each other and on thousands of star particles with softened Newtonian gravity — but views it from directly above. Each disk starts in near-circular orbit around its own core, which is what produces the spiral pattern; as the cores close in, the uneven pull across each disk stretches the near and far sides into the long tidal tails seen in real galaxy mergers, and the whole encounter reseeds itself once the cores have had time to fully interact.