Plait described how Hawking discovered how "the most powerful objects in the Universe" black holes "eventually dissolve", and how Hawking lived for another 55 years despite his ALS diagnosis.
India's Prime Minister Narenda Modhi said Hawking's "grit and tenacity" inspired generations of people throughout the world. He one said, 'It would not be much of a universe if it wasn't home to the people you love.' We will miss him forever.
The physicist and author of A Brief History of Time died peacefully at his home in Cambridge early on Wednesday afternoon (NZT).
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Hawking was diagnosed with a rare form of motor neuron disease at the age of 22 (in 1963) that later left him confined to his wheelchair.
The illness gradually robbed him of mobility, leaving him confined to a wheelchair, nearly completely paralysed and unable to speak except through his trademark voice synthesiser.
"Although there was a cloud hanging over my future, I found, to my surprise, that I was enjoying life in the present more than before".
"I am quite often asked: how do you feel about having ALS?" he once wrote.
"I try to lead as normal a life as possible, and not think about my condition, or regret the things it prevents me from doing, which are not that many", he wrote on his website.
His 1988 book "A Brief History of Time" sought to explain to non-scientists the fundamental theories of the universe and it became an worldwide bestseller, bringing him global acclaim.
Hawking's first major breakthrough came in 1970, when he and Roger Penrose applied the mathematics of black holes to the entire universe and showed that a singularity, a region of infinite curvature in spacetime, lay in our distant past: the point from which came the big bang.
They added: "His theories unlocked a universe of possibilities that we & the world are exploring".
More recently he said artificial intelligence (AI) could contribute to the eradication of disease and poverty, while warning of its potential dangers. Hawking was the first to propose a theory of cosmology using the general theory of relativity and quantum mechanics. Hawking is best known for his work on black holes, which revolutionised our understanding of the universe.
He also explained that he was able to change the accent of his computer when the technology advanced, but he decided against it.