Former President Bill Clinton says that he and wife Hillary are saddened by the death of physicist Stephen Hawking, who died at age 76.
Clinton says that Hawking "gave us profound insights into the nature of space and time, and a powerful example of overcoming adversity and making the most of life."
He added that "I will always be grateful for his Millennium lecture at the White House and his contributions to the Clinton Global Initiative."
Clinton extended his "thoughts and prayers" to Hawking's family and admirers.
The head of the Vatican's astronomical observatory has hailed Stephen Hawking as a scientist who gave a "human face" to astronomy.
Observatory director the Rev. Guy Consolmagno said Wednesday that the observatory mourned Hawking's death. He called him a "scientist of admirable intuition, who knew even more extraordinarily to give a human face to cosmology and to astronomy."
Hawking was a member of the Pontifical Academy of Sciences since 1986.
Consolmagno, who like Pope Francis is a Jesuit, told SIR, the news agency of the Italian Bishops Conference, that Hawking had studied at Cambridge with a priest who had worked at the Vatican observatory, and that the two scientists had remained good friends for life.
Buckingham Palace says Queen Elizabeth II has sent a private message of condolence to the family of physicist Stephen Hawking, who died Wednesday at age 76.
The contents of the message were not made public.
The two had met in 2014, during a charity event in London's St. James' Palace. At the time, the monarch reportedly joked with Hawking, asking him if he's "still got that American voice." Hawking replied with humor, saying: "Yes, it is copyrighted actually."
Stephen Hawking had one of the most brilliant minds in science, but he never won a Nobel Prize.
That's because the Nobel committee looks for proof, not big ideas. Hawking's theories on black holes and cosmology have yet to get the lockdown evidence that accompanies the physics prizes, his fellow scientists said.
California Institute of Technology physicist Sean Carroll says the Nobel isn't given to the smartest scientist or the one who makes the great contribution to science. Instead, he says it rewards discovery.
Hawking has often been compared to Albert Einstein, who did win a Nobel Prize. But Einstein didn't get the Nobel for his famed theory of general relativity. He got it for describing the photoelectric effect, only after it was verified by Robert Millikan, said Harvard astronomer Avi Loeb.
A spokesman for Sweden's Royal Academy of Sciences that hands out the Nobel Prizes in physics says Stephen Hawking "was a great scientist who made considerable contributions to science."
Goran Hansson says the death of 76-year-old Hawking early Wednesday "is a loss for the world of science." He declined to comment on whether Hawking should have been awarded the prestigious prize, in line with the Nobel policy.
A spokeswoman for Sweden's royal household says Swedish royals were "very sad" when receiving news of Hawking's death, adding he was "a fantastic, great and eminent researcher."
Margareta Thorgren told Sweden's TT news agency that Swedish royals met Hawking several times. He visited the royal palace in Stockholm in August 2015.
Top physicists working at the world's largest particle accelerator are paying tribute to Stephen Hawking as one of the great "stars" of physics, lauding his impact on their work and his fight against physically debilitating illness.
Director-General Fabiola Gianotti of the European Organization for Nuclear Research, known as CERN, hailed Hawking for the "enthusiasm, vitality and passion for knowledge" that he showed during visits to the Large Hadron Collider and related facilities in and around Geneva.
In a statement after Hawking's death at age 76 on Wednesday, she said: "He was a brilliant example on how to face disease with courage. He was a warrior."
CERN's head of theoretical physics Gian Giudice says Hawking's work had a "great impact" on research at the organization.
Director for Research and Computing Eckhard Elsen said Hawking "was one of the giants, and stars, of physics of the past century."
"He has inspired a whole generation with his ability to present complex science in a popular way."
The actor who played Stephen Hawking in a film about the scientist's life has described him as the funniest man he ever met.
Eddie Redmayne, who won an Oscar for his portrayal of Hawking "The Theory of Everything," paid tribute to Hawking on Wednesday.
Redmayne says: "We have lost a truly beautiful mind, an astonishing scientist and the funniest man I have ever had the pleasure to meet."
The British actor played the mathematical genius across decades of physical degeneration - all under Hawking's watchful gaze.
Redmayne said at the time of the film that Hawking wanted to live life to the full - and that he always had a glint in his eye.
The vice chancellor of the University of Cambridge is praising Stephen Hawking as an inspiration to millions.
Professor Stephen Toope said the 76-year-old Hawking, who died at his home in Cambridge, England, early Wednesday, will be missed all over the world.
Toope said that Hawking's "exceptional contributions to scientific knowledge and the popularization of science and mathematics have left an indelible legacy."
Hawking was the best-known theoretical physicist of his time. His body was attacked by amyotrophic lateral sclerosis, or ALS, when he was 21, but he stunned doctors by living with the usually fatal illness for more than 50 years.
A University of Cambridge spokesman says theoretical physicist Stephen Hawking has died.
In a statement, his children Lucy, Robert and Tim called him "a great scientist and an extraordinary man whose work and legacy will live on for many years."
The best-known theoretical physicist of his time, Hawking wrote so lucidly of the mysteries of space, time and black holes that his book, "A Brief History of Time," became an international best-seller, making him one of science's biggest celebrities since Albert Einstein.
Even though his body was attacked by amyotrophic lateral sclerosis, or ALS, when Hawking was 21, he stunned doctors by living with the usually fatal illness for more than 50 years.
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