Pick a crash
For grown-ups
This is a real physics simulation, simplified the way Toomre & Toomre did in 1972. Each galaxy's center has a heavy bulge and an invisible dark-matter halo. The 262,144 dots are stars that feel the galaxies' gravity but not each other's. The galaxy centers pull on each other and feel a drag force, so close pairs merge. Gas and new star formation are left out.
Time is real model time: 1 model unit = 47.1 million years (lengths in 10 kpc, masses in 1011 Suns). The clock counts from the moment the scene starts.
Fewer dots run faster on school laptops:
Drawing 262,144 dots. Keys: Space pause · R start over.