When Max Plank embarked upon the study of physics in the early 20 th century, his first lesson was that that there was nothing new to be unearthed in physics; Newton had already discovered the only universe in existence. But then, along came Einstein and replaced it with his own. "Newton, forgive me,' Einstein wrote in his Autobiographical Notes, "You found the only way, which in your age, was just about possible for a man of highest thought and creative power.' While Newton came up with one single system for explaining the universe, Einstein came up with two