Historical Origin of the Thinking on Big Bang Theory and an Unsolved Problem

E.Hubble confirmed the existence of Galaxies outside the Milky Way based on the measurement of the distance to some nebulae in 1923.Later he discovered Galaxy red shift,speculated that the universe is in expansion,henceforth the Big Bang theory was created.However,there remains a problem unsolved that is whether the Big Bang created the matter of the universe in whole or in part? Cosmologists of that time choose the former without hesitation,but if the two assumptions are given at the same time,one is the Big Bang created the whole universe and the other is the Big Bang created part of the universe,it is hard to figure out which one is correct based on the proof available so far.Standard Model of Universe is generated by the first assumption.We can also examine the universe with the second assumption,which will not contradict any existing facts.Based on this idea the paper carries out a new study of the universe with the second assumption as prospect.