Yes, he was the world’s best-known scientist, the galaxy’s most unlikely celebrity, a brilliant mind trapped in a failing body, a global inspiration to disabled people, and so much more.

But there was also a glint of steel in Stephen Hawking. All the accounts that try to capture the spirit of Hawking’s work tend to gloss over a grittier ingredient that was harder to convey: a relentless drive and unquenchable zest for life that has allowed him to achieve so much despite his huge physical challenges. As his daughter Lucy would often say, he was “enormously stubborn”.

I have met him on and off since the late 80s. Not once did I hear him complain or show any signs of self-pity as he explored the furthest reaches of the universe with his mind, or expanded the cosmic horizons of millions with his bestselling books.

Diagnosed with motor neurone disease in 1963 at the age of 21, he was told he’d have only two more years to live. Yet his mind managed to travel light years in the wake of that devastating diagnosis, to help turn cosmology from a fringe subject into perhaps the most compelling of all the sciences, in which he provided profound insights into gravity, space and time few have delivered since Einstein.

Play Video 3:09 Cosmology's brightest star Stephen Hawking dies aged 76 – video

In the wake of what seemed like a death sentence, it was thought that he might not survive long enough even to finish his PhD at Cambridge. What gave him something to live for was Jane Wilde, a languages student, who he had met through mutual college friends at a party the year before his devastating diagnosis.

They married in 1965, and he threw himself into his research, turning from a brilliant but lazy student into a workaholic, who first wowed his peers at the end of that decade with his work with Roger Penrose on black holes – then still something of a novelty – along with new arguments that our universe had expanded from a big bang.

He specialised in witty one-liners. On the joy of discovery: 'I wouldn’t compare it to sex, but it lasts longer.'

He was elected to the Royal Society, the world’s oldest scientific academy, in 1974, aged only 32. Martin Rees, the astronomer royal, described how he would sit hunched and motionless for hours over an abstruse book on quantum theory, too weak to turn the pages without help. Rees wondered what was going through his mind. Was it failing too?

But as he could no longer write equations, Hawking had developed a remarkable skill to use geometrical and topological images of mathematics in his head to solve problems. He was following through a “Eureka moment” that he’d had in 1970, a few days after the birth of his daughter Lucy, that would lead to his realisation that black holes are not so black. He discovered they would bleed off what is now called “Hawking radiation” and gradually evaporate, “to my great surprise”.

At first, he thought he had made a mistake in his calculations. He was eventually persuaded that the formula was correct. It was so simple and elegant that he wanted it on his tombstone. By the end of the 1970s, Hawking had advanced to hold the Lucasian professorship of mathematics at Cambridge, once held by Newton.

I first became aware of him while watching the BBC’s Horizon in 1983, which showed how his speech had become hard to decipher and slurred. Soon after, a tracheotomy left Hawking unable to speak at all: he could only communicate by raising his eyebrows or looking to select letters as they were held up on cards. By that time he had a rough draft of a book, which he’d hoped would describe his ideas to a general readership and earn something for his children.

Facebook Twitter Pinterest ‘Enormously stubborn’: the scientist pictured in 2005. Photograph: Murdo Macleod/The Guardian

When I first met him, in Berkeley, California, in 1988, he was promoting that book, A Brief History of Time. It was a runaway bestseller and one of the most successful pop science books ever. He was given a rock-star reception as he delivered talks at UC Berkeley using the speech synthesiser that has since given him his trademark American accent, selecting words and commands on a computer using a hand-clicker.

Certain words were not so easy to understand when he used his early synthetic voice. When he rang me a year or two later to discuss the thrust of an article I had asked him to write, I was too embarrassed to ask him to repeat what he had said after the second attempt, and what felt like a cosmic delay of aeons each time. I commissioned the piece, ignorant of what it was about, confident that it would be brilliant.

His hand became ever weaker, and he began operating his voice by twitching a cheek muscle. There were attempts to help him with eye-tracking, “thought reading” via an electrode cap, using facial expressions and improvements to the way he interacted with his computer. But for Hawking, getting a lot of words down required determined effort for hours.

Even when I interviewed him in front of an audience a decade ago, it would take him minutes to give prepared answers. The upside was that he specialised in witty one-liners – for instance on the joy of discovery: “I wouldn’t compare it to sex, but it lasts longer.”

The downside was that conversation was impossible, events had to be scripted, the words had to be produced as efficiently as possible, sometimes by judicious recycling and sometimes, as Rees puts it, by the promoters of causes about which Hawking may have been ambivalent.

His public persona was a long way from the stereotype of an unworldy nerd in a white coat – he was ready to express forceful political opinions, most recently on the NHS. He showed a lifelong commitment to the disabled, for instance by promoting the viral ice bucket challenge (even volunteering his children). But when he talked about subjects where he had no particular expertise, such as the rise of artificial intelligence, he was perhaps taken more seriously than he deserved.

Hawking was not publicity-shy. He adored the limelight, from appearances on Star Trek and The Big Bang Theory to The Simpsons (“Your theory of a doughnut-shaped universe is interesting, Homer. I may have to steal it.”) Need someone to run over Brian Cox in a wheelchair for a Monty Python skit? Hawking was your man.

He could easily fill major venues, such as the Albert Hall. He once lectured at Bill Clinton’s White House and then, unusually for a foreigner, returned to receive a Presidential Medal of Freedom from Barack Obama. When I visited him in his office I spotted a letter from Michelle Obama, photographs of Hawking with three popes (Hawking was a member of the Pontifical Academy of Sciences), and pictures of a visit to Easter Island. There was also Marilyn Monroe (“an old girlfriend of mine”).

One sign of his stubborn nature was that, if he was going to be in a wheelchair, he might as well travel as fast as his technology could manage. I remember going to his 60th birthday celebrations in Cambridge: after a trip in a hot-air balloon, he crashed his electric-powered wheelchair while speeding around a corner, breaking his leg.

In recent years he made more frequent visits to Papworth hospital near Cambridge. Sometimes he found it so hard to breathe he ended up on a ventilator. When we opened a 70th birthday exhibition in the Science Museum to celebrate his life, he was too ill to come. That year he had to pull out of all his celebrations in Cambridge too but, as ever, his grit saw him through.

We were given a day’s notice of a visit the following month. Hawking would pop into the museum to see the exhibit. A personal highlight was encouraging the huge crowd that gathered around him to sing him a long overdue happy birthday. He did not have to use his voice synthesiser – he responded with a huge grin and demanded to be taken on a tour of “one of my favourite places”. He stayed until 5pm.

Facebook Twitter Pinterest Eddie Redmayne plays Stephen Hawking in The Theory of Everything. Photograph: Rex/Shutterstock

In 2012 he reached perhaps his largest audience – at the opening ceremony of the London Paralympics. The following year he became $3m richer as one of the first winners of the Breakthrough prize to recognise theoretical work, in his case the discovery of Hawking Radiation from black holes – which would have earned him a Nobel prize if experimentally confirmed in his lifetime – and his deep contributions to quantum gravity and quantum aspects of the early universe.

And a second person now mastered Hawking’s voice, that paradoxical blend of machine and personality: the actor Eddie Redmayne underwent an extraordinary transformation in The Theory of Everything, a biopic based on Travelling to Infinity: My Life with Stephen by first wife, Jane. Hawking had conquered Hollywood too.

Modern science needs more Stephen and Stephanie Hawkings. Today the spotlight is focused more on invisible realms, from the fringes of the cosmos to the strangeness of the subatomic world. To understand the majesty of the cosmos, or the physics of elementary particles, you need mathematics. But in this maths-shy society, the next best thing is to have a person who is determined enough make the quest to find the mathematical underpinnings of the universe funny, romantic and real. That person was Stephen Hawking.

Roger Highfield is a former editor of New Scientist and the director of external affairs, Science Museum

The world according to Hawking





On motor neurone disease

My disabilities have not been a significant handicap in my field, which is theoretical physics. Indeed, they have helped me in a way by shielding me from lecturing and administrative work that I would otherwise have been involved in.

To Theresa May on Brexit

I deal with tough mathematical questions every day, but please don’t ask me to help with Brexit.

On aliens

Meeting an advanced civilisation could be like Native Americans encountering Columbus. That didn’t turn out so well.

On Jeremy Hunt and the NHS

Hunt had cherry-picked research to justify his argument. For a scientist, cherry-picking evidence is unacceptable.

On Trump

He is a demagogue who seems to appeal to the lowest common denominator.

On death

I have lived with the prospect of an early death for the last 49 years. I’m not afraid of death, but I’m in no hurry to die. I have so much I want to do first.