Because in 1666 an apple fell on Newton's head Or mordern view of gravity from this event was bred till Einstein came along and said Newton man you suck it's obvious that space time controls gravity you shmuck but unification wasn't to come Reletivity and so Einstein spent his later years in mental misery Then in 1968 the world of physics he did change And thorugh the year a new theory arrived and It was strange it said the world that we live in is Not comprised but of strings these tiny bit of energy these crazy wiggly things it finally made