How did the use of atomic bombs affect the event of world war 2?

It made the planned invasions of Japan at the end of 1945 and the spring of 1946 unnecessary, shortening the war by at least a year (and possibly as much as 10 years, depending on the sources you look at). It also caused the USSR to end peace negotiations with Japan and begin their already planned invasion of northern Japan sooner than they had agreed to at Potsdam (which according to some sources may have been more significant in forcing the Japanese surrender than the bombs themselves were).