Another Cinema4D Thinking Particles test, this time playing with interactions between satellites orbiting a planet.
The initial large particles (moons?) are emitted at a distance and velocity that should keep them in orbit indefinitely. When the large particles collide, they die and emit a number of smaller particles. These smaller particles die if they collide with each other, or the planet. If a small particle collides with large particle, the small one dies and slightly deflects the trajectory of the large one. The tiny orange particles are emitted from all collisions.