A grand unified history lesson

Like I was saying last time, a major goal of physics is “to unify the various fundamental forces” in a theory that offers “a more elegant understanding of the organization of the universe”. This is called a grand unified theory or GUT if it doesn’t include gravity, and a theory of everything or TOE if it does: Image from Sten Odenwald’s astronomy cafe Personally I don’t understand why anybody doesn’t include gravity. Gravity is easy. Einstein explained most of it in his 1920 Leyden Address. A…