'Physics itself disappears': How theoretical physicist Thomas Hertog helped Stephen Hawking produce his final, most radical theory of everything

In 2002, Thomas Hertog, then a theoretical physics graduate student, stepped inside Stephen Hawking's office at the University of Cambridge and saw his supervisor's eyes filled with emotion. 

Hawking's news was also a confession. The famed physicist told his student that his book, "A Brief History of Time," was wrong because it predicted a barren universe unsuitable for life, and he wanted Hertog to help him find a new theory.

So, in the last 16 years of Hawking's life, the duo, along with collaborator James Hartle, developed a new explanation for how our universe came to be. 

Live Science sat down with Hertog, now a professor at KU Leuven in Belgium, to discuss his new book "On the Origin of Time" (Penguin Random House, 2024), his decades-long collaboration with Hawking, and the mind-bending Darwinian view of the universe's origins that their work ultimately produced. 

Ben Turner: When you met Stephen Hawking, he was beginning to think that the picture of the universe's origins he had previously presented in "A Brief History of Time" was flawed, and he wanted to look for a new theory. For readers who might not know, what is the standard conception of how our universe began?

Thomas Hertog: Certainly what's standard is that there's been some sort of Big Bang — a violent, extremely odd beginning. What's been challenging is to describe what exactly happened at the Big Bang. 

What's the novelty of Hawking's contribution in "A Brief History of Time?" What was the key insight he invoked? He came up with a mathematical model of the actual beginning in his famous "no boundary proposal," in which the Big Bang is a true origin.