Updated at 9:45 a.m. ET Tuesday
Interest in "Properties of Expanding Universes" is at an all-time high: Stephen Hawking's doctoral thesis of that name crashed Cambridge University's open-access repository on the first day the document was posted online.
The Cambridge Library made several PDF files of the thesis available for download from its website, from what it called a high-resolution "72 Mb" file to a digitized version that is less than half that file size. A "reduced" version was offered that was even smaller — but intense interest overwhelmed the servers.
By late Monday local time, the well-known theoretical physicist's thesis had been viewed more than 60,000 times, says Stuart Roberts, deputy head of research communications at Cambridge. He added, "Other popular theses might have 100 views per month."
After what a Cambridge Open Access official called unprecedented interest, the library's servers seemed to be coping with the load better on Tuesday.
Hawking agreed to make the thesis available for free download on Cambridge's Apollo repository, in a deal that marks Open Access 2017 and signals the university's new push to make more academic work freely available. In a statement released by the university, Hawking said:
"By making my PhD thesis Open Access, I hope to inspire people around the world to look up at the stars and not down at their feet; to wonder about our place in the universe and to try and make sense of the cosmos. Anyone, anywhere in the world should have free, unhindered access to not just my research, but to the research of every great and enquiring mind across the spectrum of human understanding."
Before Monday's announcement, Hawking's doctoral work — officially, Ph.D. 5437 — has resided on a shelf at Cambridge, its more than 100 pages bound in a sea-green cover. On the inside cover of the thesis is a handwritten reminder: "No copying without author's consent." Anyone who wanted a copy needed to pay the library a fee of 65 pounds (about $85), the BBC reports.
Hours after it was put online, the thesis began to put stress on the Apollo site and downloads — of any of the three file versions — became impossible. A separate online entry with photographed pages remains available.
"We have had a huge response to Professor Hawking's decision to make his Ph.D. thesis publicly available to download," a spokesperson for the university said. "As a result, visitors to our open access site may find that it is performing slower than usual and may at times be temporarily unavailable."
Hawking submitted the thesis in October 1965, when he was 23 years old. Two years earlier, he had been diagnosed with amyotrophic lateral sclerosis (ALS) — the motor-neuron disease that doctors predicted would kill him within a few years.
Fans of the professor who wrote A Brief History of Time will no doubt understand that there is little point in becoming frustrated over a one-day slowdown on a Web server. In the meantime, we can offer a glimpse into what Hawking wrote.
Here's the first paragraph of Hawking's introduction:
"The idea that the universe is expanding is of recent origin. All the early cosmologies were essentially stationary and even Einstein whose theory of relativity is the basis for almost all modern developments in cosmology, found it natural to suggest a static model of the universe. However there is a very grave difficulty associated with a static model such as Einstein's which is supposed to have existed for an infinite time. For, if the stars had been radiating energy at their present rates for an infinite time, they would have needed an infinite supply of energy. Further, the flux of radiation now would be infinite. Alternatively, if they had only a limited supply of energy, the whole universe would by now have reached thermal equilibrium which is certainly not the case. This difficulty was noticed by Olders who however was not able to suggest any solution. The discovery of the recession of the nebulae by Hubble led to the abandonment of static models in favour of ones which were expanding."
The thesis consists of four chapters: "The Hoyle-Narliker theory of gravitation," "Perturbations," "Gravitational radiation in an expanding universe" and "Singularities."
The abstract of the Ph.D. paper reads:
"Some implications and consequences of the expansion of the universe are examined. In Chapter 1 it is shown that this expansion creates grave difficulties for the Hoyle-Narlikar theory of gravitation. Chapter 2 deals with perturbations of an expanding homogeneous and isotropic universe. The conclusion is reached that galaxies cannot be formed as a result of the growth of perturbations that were initially small. The propagation and absorption of gravitational radiation is also investigated in this approximation. In Chapter 3 gravitational radiation in an expanding universe is examined by a method of asymptotic expansions. The 'peeling off' behaviour and the asymptotic group are derived. Chapter 4 deals with the occurrence of singularities in cosmological models. It is shown that a singularity is inevitable provided that certain very general conditions are satisfied."
The thesis was approved in February 1966. In its citation, Cambridge has added a line stating, "This thesis has been made openly available with the kind permission of Professor Stephen Hawking."