This involved cutting an incision into the windpipe, meaning the little speech he had left would be lost. This device allowed Stephen to press a switch to select phrases, words or letters, and with its help, Stephen could communicate up to 15 words a minute. The only slight drawback was the fact that the Equalizer only had one accent: American and Stephen was very much British.
Gradually, Stephen lost the use of his hands but being ever-determined! Thanks to Richard Branson, in when Stephen was 65 years old, he got to take the trip of a lifetime: heading off to experience zero-gravity. While floating in space, Stephen ditched his chair and even managed to do backflips! Image source, EPA. The world-famous physicist often delivered lectures at universities around the world, like this one he gave at the George Washington University in Hawking met many famous world figures, including Nelson Mandela in Johannesburg in Image source, Getty Images.
He won many awards in the fields of mathematics and science and in , was awarded the Presidential Medal of Freedom by then-US President Barack Obama. His life story was made into a film, The Theory of Everything, starring Eddie Redmayne who is pictured here with Hawking.
In , Hawking spoke to an audience in Hong Kong by hologram, beamed live from his office in Cambridge. After his death, his children said his legacy would "live on for many years". Related Topics. He was happy to discard any concept that stood in the way to a deeper truth.
And if that meant the second law, then so be it. But Hawking met his match at a physics summer school in the French ski resort of Les Houches, France. Princeton University graduate student Jacob Bekenstein thought that the second law of thermodynamics should apply to black holes too.
A black hole hides its singularity with a boundary known as the event horizon. Nothing that crosses the event horizon can ever return to the outside. Bekenstein realised this was key to the entropy problem. Every time a black hole swallows matter, its entropy appears to be lost, and at the same time, its event horizon grows. So, Bekenstein suggested, what if — to preserve the second law — the area of the horizon is itself a measure of entropy?
Hawking immediately disliked the idea and was angry that his own work had been used in support of a concept so flawed. During a break from the lectures, Hawking got together with colleagues Brandon Carter, who also studied under Sciama, and James Bardeen, of the University of Washington, and confronted Bekenstein.
The disagreement bothered Bekenstein. I was just out of my PhD. Back in Cambridge, Hawking set out to prove Bekenstein wrong. Rather than destroying the idea, he had confirmed it. Hawking now embraced the idea that thermodynamics played a part in black holes. Anything that has entropy, he reasoned, also has a temperature — and anything that has a temperature can radiate.
His original mistake, Hawking realised, was in only considering general relativity, which says that nothing — no particles, no heat — can escape the grip of a black hole. That changes when quantum mechanics comes into play. According to quantum mechanics, fleeting pairs of particles and antiparticles are constantly appearing out of empty space, only to annihilate and disappear in the blink of an eye. When this happens in the vicinity of an event horizon, a particle-antiparticle pair can be separated — one falls behind the horizon while one escapes, leaving them forever unable to meet and annihilate.
The randomness of quantum creation becomes the randomness of heat. For a large black hole — the kind astronomers can study with a telescope — the temperature of the radiation is too insignificant to measure. As Hawking himself often noted, it was for this reason that he was never awarded a Nobel Prize.
Some have suggested that they should more appropriately be called Bekenstein-Hawking radiation, but Bekenstein himself rejects this. I wrote it down first, Hawking found the numerical value of the constant, so together we found the formula as it is today. I had no idea how a black hole could radiate. Hawking brought that out very clearly. So that should be called Hawking radiation. The Bekenstein-Hawking entropy equation is the one Hawking asked to have engraved on his tombstone.
The presence of these diverse constants hinted at a theory of everything, in which all physics is unified. If black holes can radiate, they will eventually evaporate and disappear. So what happens to all the information that fell in? Does it vanish too? If so, it will violate a central tenet of quantum mechanics. With the discovery of black hole radiation, Hawking had pit the ultimate laws of physics against one another.
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