6 out of 27 tho mark...
Orbital dynamics places impacting swipes at ridiculously small probabilities, certainly not 6/27, let alone and impacting swipe ending up in a stable reversed orbit.
frabigillions to one
yep i made that word up... everyone's doin it... heard it here first 
With these ratios, the coalescing gas solar system evolution planamajig thing has some work to do indeed!