Short answers, pulled from the story.
Hawking's most celebrated discovery is Hawking radiation: his 1974 theoretical prediction that black holes emit radiation and may eventually evaporate. Initially controversial, it was widely accepted as a major breakthrough in theoretical physics by the late 1970s, and the underlying law was validated in 2025 by analysis of the black hole merger GW250114.
Hawking was diagnosed with motor neurone disease in 1963 at age 21, when doctors gave him two years to live. He died on the 14th of March 2018 at age 76, having lived more than 50 years beyond that prognosis.
From 1986, Hawking used a program called the Equalizer, which let him select words and phrases by pressing a switch, initially producing up to 15 words per minute. By 2005 he controlled the device using cheek-muscle movements at roughly one word per minute, assisted by adaptive word-prediction software developed with the London startup SwiftKey.
By 2009, A Brief History of Time had sold an estimated nine million copies. It appeared on the Sunday Times bestseller list for a record-breaking 237 weeks after its publication in 1988.
The Hartle-Hawking state, published by Stephen Hawking and Jim Hartle in 1983, proposes that prior to the Planck epoch the universe had no boundary in spacetime and that time itself did not exist before the Big Bang. The model replaces the initial singularity of classical Big Bang theory with a region analogous to the North Pole, where there is no boundary but also no point further north.
Hawking's ashes were interred at Westminster Abbey on the 15th of June 2018, in the nave between the graves of Isaac Newton and Charles Darwin. His memorial stone is inscribed with the equation describing the temperature of Hawking radiation from black holes, an epitaph he chose at least fifteen years before his death.