Stephen Hawking, the famed theoretical physicist who defied a diagnosis of amyotrophic lateral sclerosis to live virtually his entire adult life with the disease – in a wheelchair and paralyzed but making constant contributions to a world few could understand – has died at age 76, a family spokesman said.
Tech executives, ranging from Apple CEO Tim Cook to Google CEO Sundar Pichai weighed in on Hawking's passing, remembering his contributions to science and humanity.
“The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.” -Stephen Hawking," Cook wrote. "We will always be inspired by his life and ideas. RIP."
Microsoft CEO Satya Nadella highlighted Hawking's contributions to science.
"We lost a great one today. Stephen Hawking will be remembered for his incredible contributions to science – making complex theories and concepts more accessible to the masses," Nadella wrote. "He’ll also be remembered for his spirit and unbounded pursuit to gain a complete understanding of the universe, despite the obstacles he faced. May he rest peacefully as his legacy and brilliance live on."
Pichai wrote: "The world has lost a beautiful mind and a brilliant scientist. RIP Stephen Hawking."
Vala Ashfar, the chief digital evangelist at cloud computing company Salesforce.com, remembered Hawking this way:
"When we see the earth from space, the message is clear: one planet, one human race. —Stephen Hawking"
Using a mathematical basis, Hawking said he was almost certain that alien life existed in other parts of the universe. "The numbers alone make thinking about aliens perfectly rational," he said. "The real challenge is to work out what aliens might actually be like."
Hawking regarded the body as a piece of technology, making a somewhat controversial statement about whether there is an afterlife. "I regard the brain as a computer which will stop working when its components fail," Hawking said. "There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark."
Although Hawking may have been incapacitated physically, he managed to write books, including the best seller "A Brief History of Time," teach physics and mathematics, deliver speeches and even float in zero gravity, all while working in the fields of cosmology and quantum gravity.
In earlier interviews, Hawking was frank about his physical restrictions. "I'm sure my disability has a bearing on why I'm well known," he said in an interview with the BBC. "People are fascinated by the contrast between my very limited physical powers, and the vast nature of the universe I deal with.
"I'm the archetype of a disabled genius, or should I say a physically challenged genius, to be politically correct. At least I'm obviously physically challenged. Whether I'm a genius is more open to doubt."
Hawking was married and divorced twice. His first wife, Jane Wilde, was a fellow student at Cambridge to whom he was married for 28 years. He then married his nurse, Elaine Mason, whom he was with for 11 years before they separated.
He is survived by three children from his first marriage, Robert, Timothy and Lucy.
Fox News contributed to this report. Follow Chris Ciaccia on Twitter @Chris_Ciaccia