The Briton was known for his work with black holes and relativity, and wrote several popular science books including A Brief History of Time.
Prof Hawking was diagnosed with motor neurone disease in 1963 at the age of 21, given only a two years to live after diagnostic. The illness left him in a wheelchair and largely unable to speak except through a voice synthesiser.
Stephen Hawking was the first to set out a theory of cosmology as a union of relativity and quantum mechanics.
He also discovered that black holes leak energy and fade to nothing - a phenomenon that would later become known as Hawking radiation.
Through his work with mathematician Sir Roger Penrose he demonstrated that Einstein's General Theory of Relativity implies space and time would have a beginning in the Big Bang and an end in black holes.
The scientist gained popularity outside the academic world and appeared in several TV shows including The Simpsons, Red Dwarf and The Big Bang Theory.
Brief factfile: Stephen Hawking
- Born 8 January 1942 in Oxford, England.
- Earned place at Oxford University to read natural science in 1959, before studying for his PhD at Cambridge
- By 1963, was diagnosed with motor neurone disease and given two years to live
- In 1974 Hawking drew on quantum theory to declare that black holes should emit heat and eventually pop out of existence. "Hawking radiation".
- In 1979, he became the Lucasian Professor of Mathematics at the Cambridge - a post once held by Sir Isaac Newton.
- In 1982, Hawking was among the first to show how quantum fluctuations – tiny variations in the distribution of matter – might give rise through inflation to the spread of galaxies in the universe.
- Published his book A Brief History of Time in 1988, which has sold more than 10 million copies.
- In the late 1990s, he was reportedly offered a knighthood, but 10 years later revealed he had turned it down over issues with the government's funding for science.
- In 2009 he received the presidential medal of freedom from Barack Obama.
- His life story was the subject of the 2014 film The Theory of Everything, starring Eddie Redmayne.
