Big physics and small physics

When Niels Bohr traveled to Britain in 1911 to study at the Cavendish Laboratory at Cambridge, the director was J.J. Thompson and the annual budget was minimal. In 1892 the entire budget for supplies, equipment, and laboratory assistants was a little over about £1400 (Dong-Won Kim, Leadership and Creativity: A History of the Cavendish Laboratory, 1871-1919 (Archimedes), p. 81). Funding derived almost entirely from a small allocation from the University (about £250) and student fees deriving from lectures and laboratory use at the Cavendish (about £1179). Kim describes the finances of the laboratory in these terms:

Lack of funds had been a chronic problem of the Cavendish Laboratory ever since its foundation. Although Rayleigh had established a fund for the purchase of necessary apparatus, the Cavendish desperately lacked resources. In the first years of J.J.’s directorship, the University’s annual grant to the laboratory of about £250 did not increase, and it was used mainly to pay the wages of the Laboratory assistants (£214 of this amount, for example, went to salaries in 1892). To pay for the apparatus needed for demonstration classes and research, J.J. relied on student fees. 

Students ordinarily paid a fee of £1.1 to attend a lecture course and a fee of £3.3 to attend a demonstration course or to use space in the Laboratory. As the number of students taking Cavendish courses increased, so did the collected fees. In 1892, these fees totaled £1179; in 1893 the total rose a bit to £1240; and in 1894 rose again to £1409. Table 3.5 indicates that the Cavendish’s expenditures for “Apparatus, Stores, Printing, &c.” (£230 3s 6d in 1892) nearly equaled the University’s entire grant to the Cavendish (£254 7s 6d in 1892). (80)

The Cavendish Laboratory exerted great influence on the progress of physics in the early twentieth century; but it was distinctly organized around a “small science” model of research. (Here is an internal history of the Cavendish Lab; link.) The primary funding for research at the Cavendish came from the university itself, student fees, and occasional private gifts to support expansion of laboratory space, and these funds were very limited. And yet during those decades, there were plenty of brilliant physicists at work at the Cavendish Lab. Much of the future of twentieth century physics was still to be written, and Bohr and many other young physicists who made the same journey completely transformed the face of physics. And they did so in the context of “small science”.

Abraham Pais’s intellectual and scientific biography of Bohr, Niels Bohr’s Times: In Physics, Philosophy, and Polity, provides a detailed account of Bohr’s intellectual and personal development. Here is Pais’s description of Bohr’s arrival at the Cavendish Lab:

At the time of Bohr’s arrival at the Cavendish, it was, along with the Physico-Technical Institute in Berlin, one of the world’s two leading centers in experimental physics research. Thomson, its third illustrious director, successor to Maxwell and Rayleigh, had added to its distinction by his discovery of the electron, work for which he had received the Nobel Prize in 1906. (To date the Cavendish has produced 22 Nobel laureates.) In those days, ‘students from all over the world looked to work with him… Though the master’s suggestions were, of course, most anxiously sought and respected, it is no exaggeration to add that we were all rather afraid he might touch some of our apparatus.’ Thomson himself was well aware that his interaction with experimental equipment was not always felicitous: ‘I believe all the glass in the place is bewitched.’ … Bohr knew of Thomson’s ideas on atomic structure, since these are mentioned in one of the latter’s books which Bohr had quoted several times in his thesis. This problem was not yet uppermost in his mind, however, when he arrived in Cambridge. When asked later why he had gone there for postdoctoral research he replied: ‘First of all I had made this great study of the electron theory. I considered… Cambridge as the center of physics and Thomson as a most wonderful man.’ (117, 119)

On the origins of his theory of the atom:

Bohr’s 1913 paper on α-particles, which he had begun in Manchester, and which had led him to the question of atomic structure, marks the transition to his great work, also of 1913, on that same problem. While still in Manchester, he had already begun an early sketch of these entirely new ideas. The first intimation of this comes from a letter, from Manchester, to Harald: ‘Perhaps I have found out a little about the structure of atoms. Don’t talk about it to anybody… It has grown out of a little information I got from the absorption of α-rays.’ (128)

And his key theoretical innovation:

Bohr knew very well that his two quoted examples had called for the introduction of a new and as yet mysterious kind of physics, quantum physics. (It would become clear later that some oddities found in magnetic phenomena are also due to quantum effects.) Not for nothing had he written in the Rutherford memorandum that his new hypothesis ‘is chosen as the only one which seems to offer a possibility of an explanation of the whole group of experimental results, which gather about and seems to confirm conceptions of the mechanismus [sic] of the radiation as the ones proposed by Planck and Einstein’. His reference in his thesis to the radiation law concerns of course Planck’s law (5d). I have not yet mentioned the ‘calculations of heat capacity’ made by Einstein in 1906, the first occasion on which the quantum was brought to bear on matter rather than radiation. (138)

But here is the critical point: Bohr’s pivotal contributions to physics derived from exposure to the literature in theoretical physics at the time, his own mathematical analysis of theoretical assumptions about the constituents of matter, and exposure to laboratories whose investment involved only a few thousand pounds.

Now move forward a few decades to 1929 when Ernest Lawrence conceived of the idea of the cyclical particle accelerator, the cyclotron, and soon after founded the Radiation Lab at Berkeley. Michael Hiltzik tells this story in Big Science: Ernest Lawrence and the Invention that Launched the Military-Industrial Complex, and it is a very good case study documenting the transition from small science to big science in the United States. The story demonstrates the vertiginous rise of large equipment, large labs, large funding, and big science. And it demonstrates the deeply interwoven careers of fundamental physics and military and security priorities. Here is a short description of Ernest Lawrence:

Ernest Lawrence’s character was a perfect match for the new era he brought into being. He was a scientific impresario of a type that had seldom been seen in the staid world of academic research, a man adept at prying patronage from millionaires, philanthropic foundations, and government agencies. His amiable Midwestern personality was as much a key to his success as his scientific genius, which married an intuitive talent for engineering to an instinctive grasp of physics. He was exceptionally good-natured, rarely given to outbursts of temper and never to expressions of profanity. (“ Oh, sugar!” was his harshest expletive.) Raising large sums of money often depended on positive publicity, which journalists were always happy to deliver, provided that their stories could feature fascinating personalities and intriguing scientific quests. Ernest fulfilled both requirements. By his mid-thirties, he reigned as America’s most famous native-born scientist, his celebrity validated in November 1937 by his appearance on the cover of Time over the cover line, “He creates and destroys.” Not long after that, in 1939, would come the supreme encomium for a living scientist: the Nobel Prize. (kl 118)

And here is Hiltzik’s summary of the essential role that money played in the evolution of physics research in this period:

Money was abundant, but it came with strings. As the size of the grants grew, the strings tautened. During the war, the patronage of the US government naturally had been aimed toward military research and development. But even after the surrenders of Germany and Japan in 1945, the government maintained its rank as the largest single donor to American scientific institutions, and its military goals continued to dictate the efforts of academic scientists, especially in physics. World War II was followed by the Korean War, and then by the endless period of existential tension known as the Cold War. The armed services, moreover, had now become yoked to a powerful partner: industry. In the postwar period, Big Science and the “military-industrial complex” that would so unnerve President Dwight Eisenhower grew up together. The deepening incursion of industry into the academic laboratory brought pressure on scientists to be mindful of the commercial possibilities of their work. Instead of performing basic research, physicists began “spending their time searching for ways to pursue patentable ideas for economic rather than scientific reasons,” observed the historian of science Peter Galison. As a pioneer of Big Science, Ernest Lawrence would confront these pressures sooner than most of his peers, but battles over patents—not merely what was patentable but who on a Big Science team should share in the spoils—would soon become common in academia. So too would those passions that government and industry shared: for secrecy, for regimentation, for big investments to yield even bigger returnsParticle accelerators became the critical tool in experimental physics. A succession of ever-more-powerful accelerators became the laboratory apparatus through which questions and theories being developed in theoretical physics could be pursued by bombarding targets with ever-higher energy particles (protons, electrons, neutrons). Instead of looking for chance encounters with high-energy cosmic rays, it was possible to use controlled processes within particle accelerators to send ever-higher energy particles into collisions with a variety of elements. (kl 185)

What is intriguing about Hiltzik’s story is the fascinating interplay of separate factors the narrative invokes: major developments in theoretical physics (primarily in Europe), Lawrence’s accidental exposure to a relevant research article, the personal qualities and ambition of Lawrence himself, the imperatives and opportunities for big physics created by atomic bomb research in the 1940s, and the institutional constraints and interests of the University of California. This is a story of the advancement of physics that illustrates a huge amount of contingency and path dependency during the 1930s through 1950s. The engineering challenges of building and maintaining a particle accelerator were substantial as well, and if those challenges could not be surmounted the instrument would be impossible. (Maintaining a vacuum in a super-large canister itself proved to be a huge technical challenge.)

Physics changed dramatically between 1905 and 1945, and the balance between theoretical physics and experimental physics was one important indicator of this change. And the requirements of experimental physics went from the lab bench to the cyclotron — from a few hundred dollars (pounds, marks, krone, euros) of investment to hundreds of millions of dollars (and now billions) in investment. This implied, fundamentally, that scientific research evolved from an individual activity taking place in university settings to an activity involving the interests of the state, big business, and the military — in addition to the scientific expertise and imagination of the physicists.

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