One of the most renowned men in scientific history, Stephen Hawking, passed away today at the age 76. Coincidentally, it’s Pi Day (3.14) and Albert Einstein’s birthday too. Known for his theories on black holes, specifically in the fields of cosmology, general relativity, and quantum gravity, Hawking lived with a rare motor neuron disease, leaving him wheelchair-bound with a voice synthesiser activated by a muscle in his cheek.

When he was 22, the British physicist was told that he had only a few years to live following the diagnosis, which had no impact on his sharp mind as he continued his works. Hawking shot to wider fame in 1988 when his book, A Brief History of Time, was published, catering to nonspecialist readers with no prior knowledge of scientific theories on cosmology.

In a statement released by his family, Hawking’s three children, Lucy, Robert, and Tim, confirmed the death of their father.

“We are deeply saddened that our beloved father passed away today. 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.”

Hawking was a celebrity, pop culture icon, and had a great sense of humour, with appearances in The Big Bang Theory, The Simpsons, and Star Trek. A movie about his life, The Theory of Everything, which covered his early works, the onset of his condition, and his relationship with his wife, won an Oscar with Eddie Redmayne nabbing the Best Actor award for playing Hawking in the movie.

Prime Minister Datuk Seri Najib Razak tweeted his condolences to Hawking’s family earlier today:

Saddened to hear that one of the world's greatest minds, Professor Stephen Hawking, has passed away. It is a great loss to the scientific community, but his legacy will live on for generations to come. My condolences to his family.

— Mohd Najib Tun Razak (@NajibRazak) March 14, 2018

Celebrities, scientists, and prominent figures from around the world reacted to Hawking’s death:

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. Stephen Hawking, RIP 1942-2018. pic.twitter.com/nAanMySqkt

— Neil deGrasse Tyson (@neiltyson) March 14, 2018

I just heard about Stephen Hawking's passing. He was both a genius and my favorite Simpsons character. We'll miss you, buddy.

— Macaulay Culkin (@IncredibleCulk) March 14, 2018

there’s a big black hole in my heart hours before Pi day. Rest In Peace @Steven_Hawking… See you in the next ❤️

— KATY PERRY (@katyperry) March 14, 2018

YOU KNEW THIS UNIVERSE BETTER THAN THE REST OF US…AND NOW YOU PLAY IN SOME FAR AWAY PART OF IT. YOU CHANGED THE WORLD AND LEFT AN IMPACT…A REMARKABLE GENIUS WE WONT SOON FORGET. ENDLESS THANK YOUS AND BLESSINGS TO THE HAWKING FAMILY. GOD BLESS STEPHEN HAWKING. pic.twitter.com/UxnNknbMaB

— Steven Tyler (@IamStevenT) March 14, 2018

I once asked Stephen Hawking in an interview what puzzles him the most in all the universe. "Women," he answered. He will be missed. R.I.P.

— Larry King (@kingsthings) March 14, 2018

Stars from science-inspired TV shows Silicon Valley and The Big Bang Theory paid tribute to Hawking as well:

RIP Stephen Hawking. Genuinely very sad to hear that. If you haven’t, read A Brief History of Time. It’ll make the world feel more amazing and beautiful and strange. It’ll also make you feel smart and stupid all at once.

— Kumail Nanjiani (@kumailn) March 14, 2018

In loving memory of Stephen Hawking. It was an honor to have him on The #BigBangTheory. Thank you for inspiring us and the world. pic.twitter.com/9rWoYqIToy

— The Big Bang Theory (@bigbangtheory) March 14, 2018

As we near Pi day (3.14) I join the global community in mourning the loss of the greatest physicist of our era. #StephenHawking 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. pic.twitter.com/o3V0TZrppj

— Mayim Bialik (@missmayim) March 14, 2018

Canadian astronaut Chris Hadfield paid tribute to Hawking as well:

Genius is so fine and rare. Goodbye Professor Hawking. You inspired and taught us all. pic.twitter.com/9Drdnv2eEe

— Chris Hadfield (@Cmdr_Hadfield) March 14, 2018

“Remember to look up at the stars and not down at your feet. Try to make sense of what you see and wonder about what makes the universe exist. Be curious. And however difficult life may seem, there is always something you can do and succeed at. It matters that you don’t just give up.” — Stephen Hawking

Rest in peace, professor.