Stephen William Hawking is an English theoretical physicist, cosmologist, author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge.
Among his significant scientific works have been a collaboration with Roger Penrose on gravitational singularities theorems in the framework of general relativity, and the theoretical prediction that black holes emit radiation, often called Hawking radiation. Hawking was the first to set forth a cosmology explained by a union of the general theory of relativity and quantum mechanics. He is a vocal supporter of the many-worlds interpretation of quantum mechanics.
He struggled a lot with his health. Hawking had experienced increasing clumsiness during his final year at Oxford, including a fall on some stairs and difficulties when rowing. The problems worsened, and his speech became slightly slurred; his family noticed the changes when he returned home for Christmas and medical investigations were begun. The diagnosis of motor neurone disease came when Hawking was 21. At the time doctors gave him a life expectancy of two years.
During the late 1960s, Hawking's physical abilities declined once again: he began to use crutches and ceased lecturing regularly. As he slowly lost the ability to write, he developed compensatory visual methods, including seeing equations in terms of geometry.