[cripplecreek]

I would think that head on collisions would be relatively rare. I’ve always assumed that the asteroids orbited mostly in the same direction so the collision speeds would be relatively low.

Interesting just the same.

[Lonesome in Massachussets]

I kinda agree with you. Orbital speeds out that way are like 17 km/sec so a head-on would be like 34 km/sec. Asteroid orbits are pretty circular, so there's not a lot of crossing and the mutual gravitational potential is small so I don't know where they'd get 5 km/sec relative velocity. Even 1 km/sec with enough mass would be pretty dramatic.

Sky and Telescope are more agnostic.