Global tributes pour in
Tributes have been paid to world renowned physicist Stephen Hawking, who has died at the age of 76.
The British scientist, who was diagnosed with a rare form of motor neurone disease aged 22, is known for his work on black holes and relativity.
Astronomer Royal Lord Rees, one of the world's most eminent scientists, described his life as a "triumph".
Others described him as a "unique individual" whose death "has left an intellectual vacuum in his wake".
The University of Cambridge, where Prof Hawking completed his PhD and went on to become Lucasian Professor of Mathematics - a role also held by Isaac Newton - called him "an inspiration to millions".
Prime Minister Theresa May praised his "brilliant and extraordinary mind" and called him "one of the great scientists of his generation" whose "courage, humour and determination to get the most from life was an inspiration".
"Professor Stephen Hawking was a brilliant and extraordinary mind - one of the great scientists of his generation. His courage, humour and determination to get the most from life was an inspiration. His legacy will not be forgotten." — PM
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Many have also praised his humour, with actor Eddie Redmayne, who portrayed Prof Hawking in film biopic The Theory of Everything in 2014, calling him "the funniest man I have ever met".
Lord Rees - who holds the most prestigious post in astronomy in the UK - said he met Prof Hawking at Cambridge University in 1964, describing him as "unsteady on his feet and speaking with great difficulty" following his diagnosis with a degenerative disease.
"Even mere survival would have been a medical marvel, but of course he didn't just survive. He became one of the most famous scientists in the world," he said
"He was diagnosed with a deadly disease, and his expectations dropped to zero. He himself said that everything that happened since then was a bonus.
"And what a triumph his life has been.
"His name will live in the annals of science; millions have had their cosmic horizons widened by his best-selling books; and even more, around the world, have been inspired by a unique example of achievement against all the odds - a manifestation of amazing will-power and determination," Lord Rees said.
Stars from the world of showbiz including Sam Smith, Nancy Sinatra and Janelle Monáe also shared tributes.
Cher recalled meeting Prof Hawking for lunch and discussing history while Katy Perry said: "There's a big black hole in my heart".
Benedict Cumberbatch, who played Prof Hawking in a 2004 BBC TV film about his life at Cambridge, said he felt "so lucky" to have known "such a truly great man", adding: "I will miss our margaritas but will raise one to the stars to celebrate your life".
"He virtually created the publishing genre of popular science," Cumberbatch said.
He praised his "wickedly funny sense of humour" and said: "You were and are a true inspiration for me and for millions around the world."
Prof Hawking's family said in a statement: "His courage and persistence with his brilliance and humour inspired people across the world.
"He once said, 'It would not be much of a universe if it wasn't home to the people you love'. We will miss him forever."
Nasa said Prof Hawking's theories "unlocked a universe of possibilities", adding: "May you keep flying like superman in microgravity, as you said to astronauts on [the International Space Station] in 2014."
Remembering Stephen Hawking, a renowned physicist and ambassador of science. His theories unlocked a universe of possibilities that we & the world are exploring. May you keep flying like superman in microgravity, as you said to astronauts on @Space_Station in 2014 pic.twitter.com/FeR4fd2zZ5
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British astronaut Tim Peake, who flew in space in 2016, said Prof Hawking "inspired generations to look beyond our own blue planet and expand our understanding of the universe".
The inventor of the World Wide Web, Sir Tim Berners-Lee, praised Prof Hawking's "colossal mind and wonderful spirit".
The European Space Agency shared a photo of Prof Hawking in 2007 experiencing zero gravity aboard a plane, alongside a caption which said he "showed us there are no limits to achieving our dreams".
"Space, here I come" - remembering world renowned physicist Stephen Hawking, who showed us there are no limits to achieving our dreams. Our thoughts are with his family. pic.twitter.com/52hpw0Tfwf
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Comedian Dara O'Briain, who has a degree in mathematics and theoretical physics and is also the presenter of the BBC's Stargazing Live, called Prof Hawking "a hero of mine".
He said: "What a privilege it was to know Stephen Hawking. His work elevated us to the extraordinary: his life pushed down a terrible, limiting disease so that he could enjoy the full joy of the ordinary.
"In both, he was a triumph of what we, as humans, can achieve."
I asked him once “How have you lived so long?” And he said “How can I die, when I have so much of the Universe left to explore?”
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So I said “Can I put that answer on a t-shirt? I promise to split the proceeds 50-50” and he weighed his answer and said “80-20”.
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Meanwhile, Professor Stephen Toope, vice-chancellor of the University of Cambridge said he has left "an indelible legacy".
"Prof Hawking was a unique individual who will be remembered with warmth and affection not only in Cambridge but all over the world," he said.
"His character was an inspiration to millions. He will be much missed."
Speaking to BBC Radio 4's Today programme, Prof Brian Cox called Prof Hawking "one of the greats" and said physicists in 1,000 years' time "will still be talking about Hawking radiation".
Prof Cox added: "There are at least three and possibly more areas where his work will be remembered as long as there are cosmologists and that's the best you can hope for as a scientist."
American astrophysicist Neil deGrasse Tyson tweeted: "His passing has left an intellectual vacuum in his wake.
"But it's not empty. Think of it as a kind of vacuum energy permeating the fabric of spacetime that defies measure."
Eddie Redmayne, who portrayed Prof Hawking in film biopic The Theory of Everything in 2014, said in a statement: We have lost a truly beautiful mind, an astonishing scientist and the funniest man I have ever had the pleasure to meet.
"My love and thoughts are with his extraordinary family."
Meanwhile, neuroscientist and The Big Bang Theory actress Mayim Bialik, who met with Prof Hawking when he starred in an episode of the series, shared a photo of him and the cast.
She described him as "the greatest physicist of our era" while the show itself thanked him "for inspiring us and the world".
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American astrophysicist George Smoot, who knew Prof Hawking for many years, also paid tribute, describing him as "very competitive".
"Whenever I did something, he wanted to do it better," Professor Smoot told BBC Radio 4's Today programme. "The one thing he was jealous of was I got the Nobel Prize before he did."
The extent of the tributes paid has led some to praise Prof Hawking's contribution to popular culture, with Oxford University biologist Sally Le Page remarking he was "as much as a cultural icon as a scientific one".
Reading through my timeline, it's abundantly clear that Stephen Hawking was as much a cultural icon as a scientific one. His forays into pop culture made people care about his research, even if they didn't understand it. If I can do just a little bit of that, I'll have done well.
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The National Portrait Gallery in London tweeted a portrait of Prof Hawking, which was commissioned in 1985 as part of a project to celebrate science's contribution to British culture.
In 1985 NPG commissioned this portrait of #StephenHawking, part of a policy to recognise the contribution of science to UK culture. He was only known to specialists at the time, it was in 1988 that he became renowned as the #ABriefHistoryofTime author. Stephen Hawking 1942-2018 pic.twitter.com/ebrt5HpUL7
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Meanwhile, the Royal Albert Hall said the "genius" Prof Hawking was the second physicist, after Albert Einstein in 1933, to ever sell out the venue.
The late genius Professor Stephen Hawking was the second Physicist ever to sell out the Royal Albert Hall in 1995. The first had been Professor Albert Einstein in 1933. #RIPStephenHawking Photo: world premiere of Interstellar Live, 2015 pic.twitter.com/E0rxpiAt8K
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The Motor Neurone Disease Association, said Prof Hawking "played a vital role" in raising awareness of the disease, which kills more than half of people within two years of diagnosis.
The @mndassoc is saddened to learn the death of Professor Stephen Hawking, Patron since 2008.Our thoughts are with Professor Hawking’s family. Throughout his inspirational life Professor Hawking played a vital role in raising awareness of motor neurone disease around the world.
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The charity said it had seen such an "influx of donations" following the announcement of Prof Hawking's death that its website had crashed.