Some Questions about the Planets

Yo!

I am not really good informed about the physics of planets, their movement or the possibilities, please excuse me, if some question sound stupid. Sorry if some questions got answered.

1. Will be there more than one sun in a solar system? (I guess you could say more than one lava planet)

2. Will be there different sizes between the planets?


3. There was a big topic about movements of the planets, if they move, will they have different movelines?


4. How much effects or rather explosions will have a crash into an planet, the visulation was nice, but actually I think it was little bit less still for that size of asteriod or not?


Pictures are taken from google imgsearch.

yours Yourtime