After contracting amyotrophic lateral sclerosis (ALS) in 1963, he was told by doctors that he had two years to live but survived for 55. The disease eventually reduced his body control to flexing a finger and eye movements, so Hawking relied on his wheelchair for movement and a computer controlled via eye-tracking to speak. The software he used to communicate was released for free, and the scientist experienced zero-gravity aboard the "vomit comet" during a flight in 2007.

In a statement, his three children said:

"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."