Professor Stephen Hawking has died at the age of 76, a spokesman for his family said.
Professor 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."