Nobel prize-winning physicist Peter Higgs, who proposed the existence of the so-called ”God particle” that helped explain how matter formed after the Big Bang, has died at age 94, the University of Edinburgh said Tuesday.

The university, where Higgs was emeritus professor, said he died Monday “peacefully at home following a short illness.”

Higgs predicted the existence of a new particle, which came to be known as the Higgs boson, in 1964. He theorized that there must be a sub-atomic particle of certain dimension that would explain how other particles — and therefore all the stars and planets in the universe — acquired mass. Without something like this particle, the set of equations physicists use to describe the world, known as the standard model, would not hold together.

Higgs’ work helps scientists understand one of the most fundamental riddles of the universe: how the Big Bang created something out of nothing 13.8 billion years ago. Without mass from the Higgs, particles could not clump together into the matter we interact with every day.