why was the Han Dynasty divided into two parts?

I think they were seperated because there were too many emperors so there wasn't time for all the emperors if they were all in one group. Anyone confirm this please?

Han Dynasty consist of Xi(west) Han Dynasty and Dong(east) Han Dynasty.The reason why Xi Han Dynasty turned into Dong Han Dynasty is civil commotion。Wang Man destroyed Xi Han Dynasty.Then,he established the Xin(new) Dynasty.But, twelve years later,Xin Dynasty was destoryed by LiuXiu（6B.C.---A.D.57).
LiuXiu established the Han Dynasty again.LiuXiu is a aristocrat.LiuXiu moved the capital.Old capital in western,the new capital in the eastern.