Stephen Hawking's PhD Thesis

Long before the bestselling books and the global fame, Stephen Hawking was a Cambridge graduate student writing a doctoral thesis. That thesis, completed in 1966 and titled Properties of Expanding Universes, marked the real beginning of his scientific career, and decades later it became an unlikely internet sensation.

What the thesis contained

The thesis examined the implications of an expanding universe within Einstein's general relativity. Its most important section dealt with singularities: the question of whether the universe must have begun from a single point of infinite density. Building on the new geometric methods of Roger Penrose, Hawking argued that, under general relativity, such a beginning was unavoidable. This line of reasoning grew directly into the singularity theorems that made his name a few years later. In other words, the seeds of his entire early career are visible in this student work.

The thesis that crashed Cambridge

For most of its life the thesis was a specialist document, read by physicists and held in the university library. That changed dramatically in October 2017, when the University of Cambridge made it freely available to the public online for the first time, through its open-access repository.

The response was extraordinary. Within days the thesis had been viewed and downloaded so many times that it overwhelmed and repeatedly crashed the repository's servers. It became by far the most requested item the university had ever published, drawing enormous public interest from people who simply wanted to glimpse the early work of the world's most famous scientist. Hawking welcomed the attention, expressing the hope that making his work openly available would inspire ordinary people, in his words, to look up at the stars and wonder about their place in the universe.

Why it matters

The episode is a small story that captures something larger. A dense, technical physics thesis from 1966 generating enough public demand to crash a major university's servers is a measure of Hawking's unique hold on the public imagination, and of a genuine, widespread hunger to engage with science. It also reflects his lifelong belief in making knowledge open and accessible, the same conviction that drove his popular books and is explored on the page about how he thought.