I was just playing a gravity simulator and i saw alot of things happening. I will only give you 2 of the theories. Number one jupiter will eat all the planets except the gas planets. While all the planets orbits it star some of the planets gravity start to mess up. Then some of the planets starts moving away from its star and then SMASH Jupiter hits it.
Number 2 some stars will one day collide together. One day stars starts to mess up and then hit a close neghibor