See, now this is an enjoyable fact. It is interesting to think that all of the forces involved in the collision will finish propelling themselves into each other within 2 minutes. One would think that it would be a little bit longer than that, because the transfer of energy between two cars in a car crash is over in a few seconds. But an asteroid colliding with a planetoid seems like it would take longer, given the amount of mass involved and the amount of deceleration that needs to take place (x km/s to 0.0000000 km/s)