I just read something about the theory of stars formation that left me puzzled. I am easily puzzled so please bear with me. The theory goes somewhat like this: There is s nebula (gas) that is contracting and increasing mass and pressure at its center until they are so big that a nuclear reaction starts. Then the extra gas is blown away. OK, fine. Problem for me is that gigantic stars many, many times bigger than our sun exist. Why? Did they not go through the accumulation of mass that started our sun? So why they did not stop there and instead continued growing? Please, unpuzzle me. Thank you.