What was the title of Stephen Hawking's doctoral thesis?

Stephen Hawking’s doctoral thesis was titled “Properties of Expanding Universes.”

Hawking wrote the thesis while studying at the University of Cambridge, where he began his doctoral work in the early 1960s under physicist Dennis William Sciama. He completed and defended it in 1966, earning a PhD in applied mathematics and theoretical physics with a focus on general relativity and cosmology.

The thesis addressed the mathematical behavior of expanding-universe models. At the time, cosmologists were debating competing ideas about the universe’s origin, including the Big Bang and steady-state theories. Hawking applied ideas about spacetime singularities to cosmology, helping establish that the universe could have begun from a singular state.

Readers sometimes confuse the title with Hawking’s later work on black holes. Black holes became central to his public reputation, but his doctoral thesis was primarily about cosmology and expanding universes. Cambridge later made the thesis available online, adding a direct primary record of its title.