Finite or Infinite Universe: Cosmological Models

Now it is time to recall, from the first chapter, that the first cosmologist may have been the mysterious Pythagoras who originated the word cosmos as a term for an ordered universe. Geometrical forms and numbers became a part of the attempts to describe the whole world. If the cosmos is ruled by mathematics, it is possible to make models for our universe and to learn about its structure. As a matter of fact, one of the first applications of General Relativity was to the universe as a whole. This marked the beginning of modern cosmology. Before that our means for creating world models were limited, although different views of the structure of the world have always been considered.