Stricken by a degenerative disease, he has overcome enormous odds to unravel the mysteries of the universe. Now he is tackling aliens.
Stephen Hawking: space invaders champion
Picture the scene: a publisher's office in the mid-Eighties. Stephen Hawking, mathematician, theoretical cosmologist and all-round master of the universe, is outlining his idea for a new best-selling book.
"Look," says the synthesised voice of Cambridge University's Lucasian Professor of Mathematics, an intellectual descendant of Isaac Newton. "It's simple. The quantum state of a spatially closed universe can be described by a wave function which is a functional on the geometries of compact three-manifolds and on the values of the matter fields on these manifolds." Publisher (gazing blankly at the paper on his desk, wishing he'd paid more attention at school): "Well, quite. Would you care for some tea?"
Cosmic mysteries surround Stephen Hawking. One is how his 1988 book, A Brief History of Time, intellectually enervating despite its title, ever found a publisher, let alone became a bestseller. Another is how a book that has been bought by so many has been read to the end by so few. Now, however, after the startling revelation this week that Hawking, 68, believes that aliens exist, are heading our way and almost certainly do not have our best interests at heart, another mystery presents itself.
Does Hawking know something the rest of us don't, meaning we should stock up on tinned food and ammo and head for the hills? Or, has he finally flipped, as bright types often do? In which case, where on earth does that leave his Theory of Everything? It's not the first time Hawking's impressive mind, more used to bending itself around black holes and quantum gravity, has wandered distractedly down into the bargain basement of pop-astronomy.
In 2008, in a speech given at George Washington University to mark the 50th anniversary of the US space agency Nasa, he told his audience he had been pondering the question "Are we alone?" and had concluded "Probably not". However, for Universe, the new Discovery Channel documentary series, he appears to have given the matter even more thought - or at least to have become a fan of Battlestar Galactica. His disturbing conclusion is that aliens exist and do so "in massive ships, having used up all the resources from their home planet … looking to conquer and colonise whatever planets they can reach".
Hawking, who last year retired as Lucasian Professor of Mathematics, can perhaps be forgiven a spot of recreational thinking after a lifetime as the brightest spark on the planet. Such is the wheelchair-bound Hawking's transcending fame - he is the only theoretical physicist to be featured in Star Trek, The Simpsons and Futurama - it is easy to forget the horrendous hand he has been dealt. He was born in 1942 in Oxford in wartime England. He followed his father to University College, defying his wish that he should study medicine but turning to physics only when he discovered his first choice, mathematics, wasn't available.
It was already obvious his brain was on the large side. "After three years and not very much work," notes his ever-so-slightly smug website biography, "he was awarded a first-class honours degree in Natural Science." "His mind," his physics tutor later noted, "was completely different from all of his contemporaries." From Oxford he went to Cambridge to study cosmology at the Institute of Astronomy before switching to his true love, mathematics, and joining the Department of Applied Mathematics and Theoretical Physics.
So far, so everyday genius, but in his first year at Cambridge the 21-year-old Hawking was diagnosed with an incurable degenerative motor neurone disease. In a sense, he was lucky. In the vast majority of cases Atrophic lateral sclerosis - ALS, or Lou Gehrig's disease - kills within three to five years. At first, he says, he felt sorry for himself - "Why should I be cut off like this?" he later wrote - but while undergoing a week-long series of tests in hospital, Hawking watched a boy in the bed opposite die from leukaemia and pulled himself together.
"Clearly there were people who were worse off than me," he wrote. "Whenever I feel inclined to be sorry for myself I remember that boy." Inspiration came to him in dreams, including one in which he faced execution. Waking up, "I suddenly realised that there were a lot of worthwhile things I could do if I were reprieved". One of those things was to fall in love, and in 1965 Hawking married Jane Wilde, a languages student with whom he went on to have three children. He was 22, she was 20 and the relationship "gave me something to live for".
His condition slowly worsened until by 1980 he needed full-time nursing care and his speech had slurred to the point where few could understand him. That ceased to be an issue in 1985 when, following a bout of pneumonia, he was given a tracheostomy and lost the ability to speak. For a while, the only way he could communicate was to spell out words by raising his eyebrows when someone pointed to the correct letter on a card. "It is," he once commented, "pretty difficult to carry on a conversation like that, let alone write a scientific paper."
Then Walt Woltosz, an American aerospace engineer whose mother had died from ALS, sent him a software program he had developed called Equalizer. Now, by pressing a switch, Hawking could select words on a screen and write or "talk" through a speech synthesiser attached to his wheelchair. Hawking seized his new lease of life enthusiastically - and the rest, as they say, is a brief history. It was the success of A Brief History of Time, published in 1988, that changed Hawking's universe.
"I don't think anyone, my publishers, my agent or myself, expected the book to do anything like as well as it did," he wrote in the introduction to one of the later editions of his book. It had been on the bestseller list for a record 237 weeks, and had sold one copy for every 750 men, women and children in the world. Fame, inevitably, opened Hawking's personal life to public scrutiny. His marriage to Jane did not survive and in 1999, in her book Music To Move The Stars, his ex-wife told the world why. As her husband's fame had increased and his physical independence decreased, Jane found her role becoming more "maternal rather than marital".
She had, she revealed, taken a lover, with her husband's blessing. The twist was that Hawking then left his wife for his nurse, Elaine Mason, who became his second wife. In 2000, Hawking was admitted to hospital with a series of injuries, including a broken arm and a black eye, and the media started to hint at domestic foul play. Hawking declined to say what had happened. Matters came to a head in 2004, when the Daily Mail claimed Hawking had been "the victim of a disturbing catalogue of 'accidents'."
The Daily Mirror went further, reporting that police were to interview Hawking's wife. He issued a statement protesting her innocence and, after a seven-month inquiry, she was publicly cleared of suspicion. Nevertheless, in 2006, the 11-year marriage ended in divorce. Of course, in time - whatever that is - all this will be dwarfed by Hawking's legacy, celebrated in his lifetime by countless awards. Among them was the US Presidential Medal of Freedom, given to him last August by President Obama.
"From his wheelchair," the president said, "he has led us on a journey to the farthest and strangest reaches of the cosmos. In so doing, he has stirred our imagination and showed us the power of the human spirit." Since his 1988 pop opus, alongside an academic output meant for just a handful of people, Hawking has built a parallel career as an author of books designed to make extraordinary ideas accessible to ordinary people.
In 2001, he had another stab at revealing the secrets of time and space to mere mortals with The Universe in a Nutshell; in 2005 - presumably because he'd twigged that the rest of us are, relatively speaking, idiots - he published A Briefer History of Time, an idiot's guide to his bestseller. Touchingly, in his own summary of his publications, Hawking lists his less demanding collaborations with his daughter, Lucy. Among the likes of Charged And Rotating AdS Black Holes And Their CFT Duals and Wormholes And Non Simply Connected Manifolds, can be found the children's books George's Secret Key To The Universe and George's Cosmic Treasure Hunt.
They are, of course, entirely in keeping with what has been his life's work - helping other, ordinary minds to boldly go where even other scientists have feared to tread. Or, as he put it in the last paragraph of A Brief History of Time (as you'd know had you got that far), his vision is that one day "we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist".