Scientist Stephen Hawking, the famous theoretical physicist and cosmologist, has died in Cambridge, England, according to the BBC via a statement from his family. He was 76.

“We are deeply saddened that our father passed away today,” Hawking’s children Lucy, Robert, and Tim said. “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 humour 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.”

Born on Jan. 8, 1942 in Oxford, England, Hawking is best known for his discoveries in relativity and black holes, which he explored in great detail in his 1988 best-seller A Brief History of Time: From the Big Bang to Black Holes. In 1963, when he was just 21 years old, Hawking was diagnosed with a rare early-onset slow-progressing form of ALS, also known as Lou Gehrig’s disease, and was expected to live just a couple years. The disease left him paralyzed and confined to a wheelchair and, following a tracheotomy, he was able to communicate via a computer and voice synthesizer.

His diagnosis and relationship with first wife Jane Wilde inspired the 2014 film The Theory of Everything starring Eddie Redmayne — who won the Best Actor Oscar — and Felicity Jones. A celebrity in his own right, Hawking left an indellible mark on popular science fiction, appearing in several TV shows through the years, including Star Trek: The Next Generation, The Simpsons, Futurama, and The Big Bang Theory,and he was the subject of several documentaries.

In addition to A Brief History of Time, Hawking authored six more books, most recently his 2013 memoir My Brief History.

Figures from the world of entertainment, politics, and science were quick to react to the news on social media, paying tribute to the award-winning scientist.

“His passing has left an intellectual vacuum in his wake. But it’s not empty,” Neil deGrasse Tyson shared on Twitter. “Think of it as a kind of vacuum energy permeating the fabric of spacetime that defies measure.”

“As we near Pi day (3.14) I join the global community in mourning the loss of the greatest physicist of our era,” Big Bang Theory star Mayim Bialik, who has a Ph.D in neuroscience, wrote on Instagram. “Stephen Hawking is free from the physical constraints of this earthly condition we all exist in and he is soaring above us now marveling at it all. Thank you Dr. Hawking for enlightening us and blessing us with your wisdom and courage.”

See those tributes and more below.