- Overcame degenerative motor neuron disease to probe mysteries of cosmos
- Advanced human understanding of origin and fate of the universe
- Worked to popularise science, wrote landmark book A Brief History of Time
Stephen Hawking's children, Lucy, Robert and Tim said in a statement: "We are deeply saddened that our beloved father passed away today. He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humour inspired people across the world. He once said, 'It would not be much of a universe if it wasn't home to the people you love.' We will miss him forever."
Much of his work was focused on bringing together relativity -- the nature of space and time -- and quantum theory -- how the smallest particles in the Universe behave -- to explain how the universe was created.
He was born on January 8, 1942, 300 years to the day after the death of the father of modern science, Galileo Galilei.
Stephen Hawking spent most of his life in a wheelchair and communicated using a single cheek muscle attached to a speech-generating device after a rare, slow-progressing form of amyotrophic lateral sclerosis (ALS) gradually paralysed him over the decades.
It was followed in 2001 by "The Universe in a Nutshell".
Stephen Hawking married Jane Wilde in 1965 and had three children. The couple split after 25 years and he married his former nurse, Elaine Mason, but they split amid allegations - denied by Hawking - that he was abused.