Seriously? That's how moons and planets are formed - same but bigger. Comets often break apart. Surely they must form too. I wouldn't be surprised if part of the cosmic soup cycle was to come in for a blaze past the sun for a crack up only to take 80 years to cool off and collect itself again before another pass, in the process rearranging molecules and in hot/cold chemistry until you get the amino chains, etc.

Yes, there are lots of high speed collisions. Every time that happens more pieces are created. They need to also either fall out of range or be drawn back, for a less high speed collision - creating more debris. This cycle would continue until the pieces either drifted out of the gravity well or settled down in the center of it. It might be millions or billions of years until another significant impact with nothing to do but settle and seem lifeless.

This is an epic cosmic story - and everything we know about, all the people that ever were and ever will be, and this computer screen - all just cosmic schmutz at one point - and will be again. That's what blows my mind. Infinity times infinity and more.