Big Science Chapter One A Heroic Time Ernest Rutherford was one of science''s Great Men, a towering figure who drove developments in his era rather than riding in the wakes of others. To an acquaintance who observed, "You''re always at the crest of the wave," he was said to have replied: "Well, after all, I made the wave, didn''t I?" He was loud, with a boisterous laugh and a hearty appreciation of what was known in his time as "smoking-room humor." C. P. Snow, a youthful associate of Rutherford''s who would win literary fame with novels set in the corridors of academia and government, remembered Lord Rutherford as "a big, rather clumsy man, with a substantial bay window that started in the middle of the chest" and "large staring blue eyes and a damp and pendulous lower lip." Born in 1871 to a handyman and his wife in New Zealand when it was a remote outpost of the British Empire, Rutherford became an intuitive theorist and the preeminent experimental physicist of his age. No one could question his talent for divining the significance of the results produced by his elegant handmade equipment. "Rutherford was an artist," commented his former student A.

S. Russell. "All his experiments had style." Rutherford was twenty-four when he first came to Cambridge University''s storied Cavendish Laboratory on a graduate scholarship. It was 1895, a fortuitous moment when physicists were pondering a host of strange new physical forces manifested in their apparatuses. Only a month before Rutherford''s arrival, the German physicist Wilhelm Roentgen had reported that a certain electrical discharge generated radiation so penetrating it could produce an image of the bones of a human hand on a photographic plate. Roentgen called his discovery X-rays. Roentgen''s report prompted the Parisian physicist Henri Becquerel to look for other signs of X-rays.

His technique was to expose a variety of chemical compounds to energizing sunlight. He would seal a photographic plate in black paper, cover the paper with a layer of the candidate compound, place the arrangement under the sun, and check back later to see if a shadow appeared on the sealed plate. During a stretch of overcast Paris weather in February 1896, he shut away in a drawer his latest preparation: a uranium salt sprinkled over the wrapped plate, awaiting the sun''s reemergence from behind the clouds. When he developed the plate, he discovered it had been spontaneously exposed by the uranium in the darkened drawer. Marie Curie and her husband, Pierre, soon established in their own Paris laboratory that Becquerel''s rays were produced naturally by certain elements, including two that they had discovered and named polonium, in honor of Marie Curie''s native Poland, and radium. They called the phenomenon "radioactivity." (Becquerel and the Curies would share the 1903 Nobel Prize for their work on what was originally called "Becquerel radiation.") Other scientists launched parallel inquiries to unravel the mysteries lurking within the atom''s interior.

Cavendish director Joseph John "J. J." Thomson, Ernest Rutherford''s mentor, discovered the electron in 1897, thereby establishing that atoms were divisible into even smaller particles--"corpuscles," he called them. Thomson proposed a structural model for the atom in which his negatively charged electrons were suspended within an undifferentiated positively charged mass, like bits of fruit within a soft custard. Irresistibly, this became known as the "plum pudding" model. It would prevail for fourteen years, until Rutherford laid it to rest. Rutherford, meanwhile, had busied himself examining "uranium radiation," his term for the emanations discovered by Becquerel. In 1899 he determined that it comprised two distinct types of emissions, which he categorized by their penetrative power: alpha radiation was easily blocked by sheets of aluminum, tin, or brass; beta rays, the more potent, passed easily through copper, aluminum, other light metals, and glass.

Rutherford had relocated to Montreal and a professorship at McGill University, which featured a lavishly equipped laboratory funded by a Canadian businessman, in an early example of scientific patronage by industry. Working with a gifted assistant named Frederick Soddy, who would coin the term isotope for structurally distinct but chemically identical forms of the same element, Rutherford determined that the radioactivity of heavy elements such as uranium, thorium, and radium was produced by decay, a natural transmutation that changed them by steps--in some cases, after minutes; in others, centuries, years, or millennia--into radioactively inert lead. Eventually alpha rays were identified as helium atoms stripped of their electrons--that is, helium nuclei--and beta rays as energetic electrons. The work earned Rutherford the 1908 Nobel Prize in chemistry. By then, he had already returned to Britain to take up a professorship at the University of Manchester. There he would make an even greater mark on science by taking on the core question of atomic structure. "I was brought up to look at the atom as a nice hard fellow, red or grey in color, according to taste," he remarked years later of the plum pudding model. But although he speculated that the atom was mostly empty space rather than a homogenous mass speckled with charged nuggets, he had not yet conceived an alternative model.

With two Manchester graduate assistants, Hans Geiger and Ernest Marsden, he set about finding one, using alpha particles as his tools. As he knew, these were deflected somewhat by magnetic fields but, curiously, even more on their passage through solid matter--even through a thin film such as mica. This suggested that the atomic interior was an electromagnetic maelstrom buffeting the particle on his journey, not a serene, solid pudding. Rutherford experimented by bombarding gold foils with alpha particles emanating from a glass vial of purified radium. Geiger and Marsden recorded the particles'' scattering by observing the flash, or scintillation, produced whenever one struck a glass plate coated with zinc sulfide. This apparatus displayed Rutherford''s hallmark simplicity and style, but the procedure was unspeakably onerous. The observer first had to sit in the unlighted laboratory for up to an hour to adjust his eyes to the dark, and then could observe only for a minute at a time because the strain of peering at the screen through a microscope tended to produce imagined scintillations mixed with the real ones. (Geiger eventually invented his namesake particle counter to relieve experimenters of the tedium.

) The experiment showed that most of the alpha particles passed through the foil with very slight deflection or none at all. But a tiny number--about one in eight thousand--bounced back at a sharp angle, some even ricocheting directly back at the source. Rutherford was astonished by the results. "It was almost as incredible as if you fired a fifteen-inch shell at a piece of tissue paper, and it came back and hit you," he would relate years later, creating one of the most cherished images in the history of nuclear physics. It was not hard for him to understand what had happened, for the phenomenon could be explained only if the atom was mostly empty space, with almost all of its mass concentrated within a single minuscule, charged kernel. The deflections occurred only when the alpha particle happened to strike this kernel directly or come close enough to be deflected by its electric charge. The kernel, Rutherford concluded, was the atomic nucleus. Rutherford''s discovery revolutionized physicists'' model of the atom.

But it was by no means his ultimate achievement. That came in 1919, he reported an even more startling phenomenon than the tissue-paper ricochets of 1911. Rutherford had again relocated, this time to Cambridge, where he assumed the directorship of the Cavendish. The laboratory had opened in 1874 under the directorship of James Clerk Maxwell, who was a relative unknown at the time of his appointment; within a few short years, however, he had published the work on electricity and magnetism that made his worldwide reputation and established the Cavendish by association as one of Europe''s leading scientific centers. Maxwell''s conceptualization of electricity and magnetism as aspects of the same phenomenon, electromagnetism, would stand as the bridge between the classical physics of Sir Isaac Newton and the relativistic world of Albert Einstein, and his Cavendish would reign as the living repository of the British experimental tradition in physics. In Rutherford''s time, the Cavendish reveled in its tatty grandeur, the epitome of small science in an institutional setting. The building was shaped like an L around a small courtyard: three stories on the long side, the top floor, with its gabled windows, crammed under a steeply raked roof. Inside the building were a single large laboratory and a smaller lab for the "professor," a room for experimental equipment, and a lecture theater.

There Rutherford held forth three times a week to an audience of about forty students, occasionally consulting a few loose pages of notes drawn from the inside pocket of his coat. Physicist Mark Oliphant, arriving at the Cavendish from Australia in the mid-1920s, remarked on its "uncarpeted floor boards, dingy varnished pine doors an.