LONDON, March 14 (Xinhua) -- Renowned British physicist Stephen Hawking has died at the age of 76, a family spokesman said Wednesday.

The professor died peacefully in his sleep at his home in Cambridge in London, the spokesman said.

Born on Jan. 8, 1942 -- exactly 300 years after the death of the father of modern science, Galileo Galilei -- Hawking believed that science was his destiny.

"My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all," the physicist once said.

In most of his lifetime, Hawking was speechless, yet extraordinary.

After being diagnosed with amyotrophic lateral sclerosis (ALS), a form of motor neurone disease that attacks the nerves controlling voluntary movement after his 21st birthday in 1963, Hawking became wheelchair-bound and dependent on a computerized voice system for communication.

"However bad life may seem, there is always something you can do, and succeed at," said Hawking, who fought his whole life against fate. "While there's life, there is hope."

A GREAT SCIENTIFIC GENIUS

In 1974, he became one of the youngest fellows of Britain's most prestigious scientific body, the Royal Society, at the age of 32.

In 1979 he was appointed Lucasian Professor of Mathematics at Cambridge University, where he had moved from Oxford University to study theoretical astronomy and cosmology.

Hawking discovered the phenomenon which became known as Hawking radiation, where black holes leak energy and fade to nothing. He was renowned for his extraordinary capacity to visualize scientific solutions without calculation of experiment.

His 1988 book "A Brief History of Time" sought to explain to non-scientists the fundamental theories of the universe and it became an international bestseller, bringing him global acclaim.

Hawking said he wanted to show that disability was no bar to achievement and to encourage interest in space, where he believed humankind's destiny lay.

"I think the human race has no future if it doesn't go into space," he said.

"I believe life on Earth is at an ever-increasing risk of being wiped out by a disaster such as sudden global warming, nuclear war, a genetically engineered virus or other dangers."

Hawking dedicated his whole life to unlocking the secrets of the Universe

"There's nothing like the thrill of discovery, when you find something that no one knew before," he said.

He is the recipient of many awards, medals and prizes, including the Albert Einstein Award, the most prestigious in theoretical physics.

A MEANINGFUL LIFE

Hawking was twice married and divorced.

He married undergraduate Jane Wilde in July 1965 and the couple had three children, Robert, Lucy and Timothy. But Hawking tells in his 2013 memoir how Wilde became more and more depressed as her husband's condition worsened.

Hawking married Elaine in 1995. That relationship also ended in divorce after 12 years, though only after a police investigation into accusations that Elaine had physically abused her husband.

The love story between Hawking and Wilde was retold in the 2014 film "The Theory of Everything", which won Britain's Eddie Redmayne the best actor Oscar for his portrayal of the scientist.

In 2007, Hawking published a children's book, "George's Secret Key to the Universe", with his daughter, Lucy, seeking to explain the workings of the solar system, asteroids, his pet subject of black holes and other celestial bodies.

Hawking also appeared as himself in an episode of the BBC comedy series, REd Dwarf and as a hologram of his image in "Star Trek: The Next Generation", while his voice appeared in Pink Floyd songs.

He believed his disease brought some benefits. He said before he had the illness he had been bored with life.

"Life would be tragic if it weren't funny," Hawking said.