How silly of me
Yes, of course, iron fillings. It's been such a long time since seeing this experiment in elementary school. How silly of me.
4 publicly visible posts • joined 18 Aug 2010
To me, this looks very similar to the effect you would get by placing lead pencil shavings on to a piece of paper with a magnet underneath. Perhaps the debris from the collision is caught in an electric field of some sort and it has nothing to do with gravity, the "solar wind", or the shapes of the colliding asteroids.
This might also explain why the particles are not moving apart as fast as would be expected.