“I think my greatest achievement will be my discovery that black holes are not entirely black,” Hawking explained last year when being interviewed after his 75th birthday.
“Quantum effects cause them to glow like hot bodies with a temperature that is lower, the larger the black hole,” he says, summarising his theory that is known as “Hawking’s radiation.”
The result of his research, published in 1975, came as a complete surprise to the academic world and showed a deep relationship between gravity and thermodynamics.
“I think this will be key to understanding how paradoxes between quantum mechanics and general relativity can be resolved,” he says.
Hawking was confined to a wheelchair at the age 22 after developing a form of motor neuron disease, which eventually paralyzed him almost completely, taking away his ability to speak.
He communicated via a voice generator that produces a metallic voice and that he could control with movements of his cheek, after he lost control over his fingers to use a keyboard.
But over the fifty years that he suffered the illness, ALS or Amyotrophic Lateral Sclerosis, he managed put forward some spectacular theories that are now widely discussed.
Colleagues in the field were shocked when they learned from Hawking’s death.
“That was of course a big surprise to all of us,” Heino Falcke, an astronomer at the University of Nijmegen, told RFI.
“We all knew that he was sick for a long time, and it was amazing to see what he was able to do under his conditions to such an old age. It is still a sad day, I think.”
Others remember him fondly. “I got to know Stephen Hawking very well,” says Vincent Icke, a professor of theoretical astrophysics at Leiden University, who worked together with Hawking in Cambridge in the 1970s.
“We talked about physics, we talked about his ideas about general relativity and things.
“He was a very communicative and outgoing person and all the more tragic of course that later in his life he could not speak any more because we physicists, we talk a lot, believe it or not.
“Not only for me but for the colleagues at Cambridge at the time it was shocking to see how quickly his health deteriorated. But of course we were happy that he survived for so long,” he says.
Hawking and Einstein
Hawking is often compared to Einstein, but how do their theories relate?
Hawking studied Einstein’s general relatively extensively, but had to conclude that some elements didn’t add up.
“It seems that Einstein always had the final word in describing how space and time should be described,” says Falcke.
“And Hawking punched a hole into this. And essentially showed that if you try to bring quantum physics, if you bring that into contact with general relativity that Einstein developed, the two don’t go together.
“Especially at the event horizon of the black holes, which is where those two things don’t really rhyme. And something new happens. A thing that is not in the theory of Einstein. So this gives actually hope that there is something more, something deeper to be discovered in the future.
Meanwhile, after publishing his Brief History of Time, that became a worldwide bestseller, he shot to fame, featured in talk shows, appeared in The Simpsons and even had an Oscar-winning movie about his life, The Theory of Everything, by James Marsh, starring Eddie Redmayne.
In spite of his fame, colleagues in the field continued to talk highly of him. His work was “absolute top of the line, really fantastic” says Icke.
But in spite of his hero-status, he did not manage to attract many followers – academic and social hurdles are still too high, proving Hawking to be a single exception of someone who made it to the top of academia in spite of a severe physical handicap.
“If you look at diversity in science, it is still not true that everybody is equally able to perform on the highest level of science and that we let them to do just that,” says Falcke.
“I see very few people who are handicapped, and certainly as seriously handicapped as him who have actually a chance to be heard in science and to contribute.
“And that maybe is a bit of a sad story, that I think while his example has inspired many it still hasn’t opened the doors for a broader range of people to actually be like him in science to overcome these hurdles,” he says.
Stephen Hawking was born exactly 300 years after Galileo died, on January 8 and he died 139 years after Albert Einstein was born, on March 14. Is that a cosmic coincidence, or was it carefully planned?