I've been searching and trying to find an answer to this. I'm not scholar or physics major. I'm asking for some guidance about this subject. The big bang theory, leaves me with the impression that atoms can change size. Is this true? Can gravitational forces compress, can atoms become smaller? What regulates an atom's size? Can adjusting the space/time fabric change the size of an atom? Thank you for your time. I'm really wondering how all the atoms can fit into the space of a green pea, as computer models suggest.