Stephen Hawking is a scientist.
Cosmology . Physical cosmology is the scholarly and scientific study of the origin , large-scale structures and dynamics , and ultimate fate of the universe , as well as the scientific laws that govern these realities . Stephen William Hawking , ( born 8 January 1942 ) is an English theoretical physicist , cosmologist , author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge . Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize , explain and predict natural phenomena . The advancement of science depends in general on the interplay between experimental studies and theory .