March 14 (UPI) -- Stephen Hawking, one of the world's best-known physicists and the author of A Brief History of Time, has died, a family spokesman confirmed Tuesday night. He was 76.
"We are deeply saddened that our beloved father passed away today," read a statement from Hawking's children, Lucy, Robert and Tim. "He was a great scientist and an extraordinary man whose work and legacy will live on for many years. His courage and persistence with his brilliance and humor 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."
Hawking was born in Oxford, Britain, on Jan. 8, 1942 -- the 300th anniversary of the death of Galileo Galilei, the Italian astronomer and physicist.
In his early 20s, Hawking was diagnosed with amyotrophic lateral sclerosis, ALS or Lou Gehrig's disease. But his form of the neurodegenerative disease was a rare one that progressed slowly as he pursued his Ph.D., in physics at Cambridge University.
As his physical condition deteriorated, Hawking lost the use of his legs and had to communicate through a computer-based device that ultimately became one of the astrophysicists's best-known characteristics.
Hawking's expertise in astrophysics and cosmology rose to prominence in 1988 with the publication of A Brief History of Time. Using mostly non-technical terms to explain a wide range of heady topics, including the Big Bang Theory and black holes, Hawking's book became an international bestseller, selling more than 10 million copies in 35 languages.
"He agreed that that book, Brief History of Time, was probably the least-read, most-bought book ever," Leonard Mlodinow, a physicist and science writer at the California Institute of Technology, told NPR. Mlodinow worked on a shorter version of the book, appropriately titled, A Briefer History of Time.
The book brought Hawking worldwide fame and he became a scientist pop star, giving interviews to mainstream news outlets and appearing in cameos on The Simpsons. And even as his ALS continued to deteriorate his physical condition, he continued to give lectures through his computer-based communication device.
"I write the lecture beforehand then save it to disk," Hawking said on a section of his website where he describes the device. "I can then use a part of the ACAT software called Lecture Manager to send it to the speech synthesiser a paragraph at a time. It works quite well and I can try out the lecture and polish it before I give it."
Hawking's physical condition did not hinder him from living a full life. In addition to achieving pop star status through his work, The New York Times pointed out he visited every continent, married twice, fathered three children and continued to speak out on a wide range of issues, including climate change.
"I want to show that people need not be limited by physical handicaps as long as they are not disabled in spirit," Hawking said in 2007, shortly after taking a zero gravity ride aboard a special Boeing 727-200.
He was portrayed by Eddie Redmayne in the 2014 biopic The Theory of Everything, which was nominated for an Oscar.
"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," tweeted Neil deGrasse Tyson.