The Perfect Machine

by Ronald Florence

  14

  Change of Guard

  Caltech was a tiny school with a big reputation. Only a decade after its founding, the superb faculty Hale, Noyes, and Millikan had recruited had brought the institution to the front ranks of the hard sciences. There were still only few dozen regular faculty members, but the list of speakers who trekked to the red-tile roofed stucco buildings under the visiting scholars program included Albert Michelson, Michael Pupin, and the cream of European physics: Niels Bohr, Max Born, Paul Dirac, Erwin Schrodinger, and Werner Heisenberg. Caltech had come a long way from its shaky beginnings as a polytechnic school.

  In the spring of 1931 Einstein joined the faculty as a visiting professor. Einstein was a celebrity, his name celebrated in Cole Porter songs,

  Your charm is not that of Circe with her swine

  Your brain would never deflate the great Einstein.

  and his theory in e. e. cummings’s poems,

  … lenses extend

  unwish through curving where when till unwish

  returns on its unself.

  In Southern California, Will Rogers wrote, Einstein “ate with everybody, talked with everybody, posed for everybody that had any film left, attended every luncheon, every dinner, every movie opening, every marriage and two-thirds of the divorces. In fact, he made himself such a good fellow that nobody had the nerve to ask him what his theory was.”

  Except at Caltech. Richard Tolman, professor of physical chemistry and mathematical physics and dean of the graduate school, had been at Caltech for almost a decade, working on relativity, statistical mechanics, and cosmology. Ever since Hubble had discovered red shifts in the light from distant galaxies and had begun to calculate the speed of recession of those galaxies, Tolman had worked to integrate Hubble’s findings into a workable cosmology of curved space. Hubble wasn’t much of a relativity scholar, but he loved the publicity, especially the photographs, always in a tweed jacket with his trademark pipe. When Einstein went to Mount Wilson and posed for photographs at the one-hundred-inch telescope, Hubble gave his usual explanations about how the giant telescope was used to determine the structure of the universe. “Well, well,” Mrs. Einstein said, “My husband does that on the back of an old envelope.”

  The one-hundred-inch telescope was working hard. Hubble and Humason had a near monopoly of dark time on the telescope to carry on their search for distant galaxies. They used every trick to reach farther and farther out with the one-hundred-inch telescope, including new emulsions for the spectrograms, and new auxiliary lenses. Hubble soon had images from enough nebulae to derive a classification scheme for galaxies, his famed tuning fork with elliptical galaxies on the handle and the spiral and barred-spiral types classified by their position along the two tines. The derivation of a morphology of distant galaxies, less than a decade after the very existence of “island universes” had been demonstrated, elevated cosmology into a hard science.

  With each improvement in technique, Hubble and Humason measured bigger red shifts, which translated into larger velocities of recession and more distant objects. In February 1931, using a new Payton spectrograph objective, which had been developed as part of the two-hundred-inch project, they succeeded in recording the spectrum of a minute spiral nebula of the seventeenth magnitude, “far beyond the reach of all other instruments.” To record the spectrum Humason had to keep the faint object centered on the slit of the spectrogram for seventeen hours, over three nights. “The nebulae are becoming so faint,” he wrote, “that they are difficult to see.” From the measured red shift, Hubble calculated that the galaxy was receding at close to twenty thousand kilometers per second. “Either the entire universe is flying apart,” Hale wrote when he heard the report, “or a new and fundamental physical law must be elucidated to account for these extrordinary phenomena.”

  The consequences of Hubble’s work were as exciting for cosmology as for observational astronomy. The universe was no longer the stable constant it had always seemed. Hubble and Humason had discovered thousands of “island universes,” of infinite variety, streaming away from one another at inconceivable velocities. What could account for this seeming entropy? Tolman set to work on the problem and gradually concluded that the match between Hubble’s data and Einstein’s theory of gravity without the cosmological constant was too compelling to ignore.

  For Tolman, Einstein’s visit to the campus was a grand opportunity.

  Tolman, a witty man with a deadpan delivery, also served as campus toastmaster, a duty that reached fever pitch when Einstein arrived in Pasadena. In the evenings he would introduce Einstein at various functions. During the days Einstein attended colloquiums and private meetings with faculty and graduate students, including enough sessions with Tolman that he was finally persuaded that the cosmology of an expanding universe was probably correct. Einstein had actually wavered on the cosmological constant in a paper. When Sir Arthur Eddington chided Einstein about dropping the constant, Einstein said, “I did not think the paper very important myself, but de Sitter [Willem de Sitter, coauthor of the paper] was keen on it.” De Sitter also didn’t want the rap. “You will have seen the paper by Einstein and myself,” he wrote to Eddington. “I do not myself consider the result of much importance, but Einstein seemed to think that it was.”

  Five months after he left Caltech, Einstein wrote Millikan from Berlin to report that “further thought regarding Hubbel’s [sic] observations have proved that the phenomena adapts itself very well to the theory of relativity.” The big telescopes in Southern California had already reached far enough to correct Einstein’s original theory.*

  Hale had envisioned a broad program of cooperation between the faculties at Caltech and the staff of the Mount Wilson Observatory. With Hubble, Walter Baade, who had originally come on a visiting fellowship from Hamburg, van Maanen, and a constant influx of bright younger fellows, Mount Wilson was the preeminent group of observational astronomers. Their offices on Santa Barbara Street were a short drive or a long walk from the Caltech campus. Despite the proximity, and Hale’s hopes, the only open cooperation was the Astronomy and Physics Club, a joint effort of the Bridge Laboratory and the Mount Wilson Observatory, which met in a weekly colloquium for featured speakers.

  The formal colloquiums were a Band-Aid over the scar tissue from the dispute that had almost lost the grant in May 1928. John Merriam, still chafing that the big telescope had gone to tiny Caltech instead of to the world-famed Mount Wilson Observatory, did all he could to limit the cooperation between the institutions. Caltech faculty were not granted the same observation privileges as Mount Wilson staff, and even those members of the Mount Wilson staff whose salaries were paid in part by Caltech because they were working on the two-hundred-inch telescope project—Anderson, Pease, and a young astronomer named Sinclair (“Smitty”) Smith—were not allowed the full privileges of Caltech faculty.

  The institutional distrust was mutual. After the experiences of 1928, and subsequent meetings that confirmed their impressions of Merriam as a stubborn, insecure, and petty administrator, Millikan and his colleagues on the Observatory Council concluded that as long as Merriam headed the Carnegie Institution, any meaningful program of cooperation between the two institutions was impossible. Hale usually wasn’t one to bear a grudge, but this time even he agreed. Since Merriam wasn’t scheduled to retire until 1938, and had made it clear that he was not leaving a day earlier, the council concluded that Caltech would need its own astrophysics faculty.

  In Caltech tradition the new faculty of astrophysics started with a building, funded by the grant for the telescope. Porter designed the astrophysics laboratory. Hale wanted a solar telescope for the building, with a roof-mounted coelostat to follow the sun and a deep shaft to bounce the light in a long focal path to a spectroheliograph like the instrument he used at his solar lab. Everyone agreed that there should also be a small telescope for the astronomy students. Porter, who had worked with amateur astronomers in Vermont, had strong ideas about what
features made a telescope convenient and useful. This was one area in which Porter was not disputed by others on the staff.

  The two telescope domes on the roof came to characterize the new building on California Street, next to the Bridge Laboratory of Physics. From a fund-raising standpoint, separate buildings were a good idea. Donors eager to see their names in bronze would fund anything from an entire building to a lab or a broom closet. But separate buildings did little to encourage the cooperation between faculties and disciplines that Hale had dreamed of when he first proposed the telescope.

  The first faculty member at Caltech who could be called an astrophysicist was Fritz Zwicky, a Bulgarian-born Swiss physicist who came to Pasadena on a Rockefeller fellowship. Zwicky was neither shy about his own abilities nor reluctant to voice his opinions. Most junior faculty trembled with fear in the presence of Robert Millikan. Zwicky, too young, naive, or bold to know what was expected, not only didn’t turn to jelly but accused Millikan of never having had an idea of his own.

  “All right, young man,” Millikan answered. “How about you?”

  Zwicky said, “I have a good idea every two years. You name the subject, I bring the idea!” Millikan on the spot ordered Zwicky to take on an astrophysics problem.

  Forced to work with blackboard and chalk because Caltech didn’t yet have a telescope, Zwicky turned his efforts to trying to explain the apparent radial velocities of the spiral galaxies. One explanation was Einstein’s, now already famous even outside the narrow circles of astrophysics. Zwicky, undaunted by Einstein’s fame or the widespread acceptance of his theory, took on the problem.

  Zwicky wasn’t successful in deriving an alternative to relativity, but in time he became an institution at Caltech and in the world of astrophysics for his often precocious and almost always eccentric ideas. It was Zwicky who first posited the existence of neutron stars, supernovas, dark matter, gravitational lensing, and clusters of galaxies—all long before anyone had evidence to prove or disprove his theories. The courses he taught were by reputation ferociously hard. In the required course in mechanics, Zwicky would assign terrifyingly difficult problems, then call on the least competent students to go to the board and work through the solution under his ruthless questioning. Years later, while walking across the campus, he admitted to one former student, “Some of those goddamn problems I could not do myself.”

  Even outside the classroom Zwicky was a terror. In a field usually characterized, at least in public, by gentlemanly behavior, Zwicky was consistently, and apparently deliberately, intemperate. His collaborations rarely lasted. His research on velocities of members of the Virgo cluster, which led to his questioning about the “missing matter” in the universe, came from data supplied by Sinclair Smith, an astronomer at Mount Wilson who had designed and built a special spectrograph for the purpose. Smith received no credit in Zwicky’s subsequent work. Smith’s spectrograph was based on the principle of the Schmidt telescope, a design Zwicky later claimed to have brought to America from Germany.

  At seminars, he was as quick with an insult as with an answer. “Why are your ears so big?” he asked one faculty member. Understandably, he wasn’t popular with his colleagues. With technicians, graduate students, and secretaries Zwicky liked to debate, in any of six languages, what kind of “bastards” his faculty colleagues were. His usual conclusion was that they were “spherical bastards” because no matter which way you looked at them they were still bastards. Other physicists learned to give him a wide berth.

  Although Zwicky was the only faculty member assigned to astrophysics, others also worked on astrophysics problems. Ira Bowen, a bright young physicist with a specialty of spectroscopy, worked as Millikan’s research assistant. When he got his Ph.D. in 1926, Millikan hired him for the Caltech physics faculty.* Bowen had begun working on spectra from the big telescopes at the Lick Observatory, where he had been a Morrison Fellow. In 1927 he identified lines in the spectra of gaseous nebulae, which had previously eluded explanation. The lines had been so puzzling that earlier astronomers had even invented a hypothetical element, not known on earth (nebulium), to account for the spectral lines. Bowen identified the lines as “forbidden” emissions of doubly ionized oxygen, ions of oxygen that were missing two electrons—a form unstable on earth but possible in the near vacuum of space. Walter Adams called Bowen’s work “one of the most brilliant astronomical discoveries of recent years.”

  Hale was enthusiastic about Bowen’s work. Spectroscopy was something he understood. Other new developments in astronomy were moving too fast for any but young men on top of the field. Einstein had written to George Hale in 1913 to explain how the sun would bend starlight passing nearby, but Hale found relativity impenetrable. In letters to Max Mason at the Rockefeller Foundation, Hale enthusiastically reported Zwicky’s efforts to come up with an alternate solution. Mason, an applied physicist who had done his schooling and research before relativity was part of the theoretical physics curriculum, also was not comfortable with space and time as terms and thought they were “ridiculous” when applied to atomic structure, “perhaps it may turn out that they are as bad when applied to the universe as a whole.”

  Max Mason was a godsend to the telescope project. In 1928 a committee of trustees of the various Rockefeller-funded foundations concluded that the overlapping jurisdictions of the foundations were inefficient and unproductive and recommended that all programs from any of the foundations relating to “the advancement of human knowledge” be transferred to the Rockefeller Foundation. Rose, alone among the high officials of the foundations, opposed the consolidation, which went into effect with his retirement. The Rockefeller Foundation inherited the telescope project. Arnett was the program officer for physical sciences at the Rockefeller Foundation, but Mason was personally interested in the telescope project, and starting with the meeting when Hale was called to New York to discuss the site of the telescope, Mason gradually took over the role of foundation contact for the project.

  Before coming to the Rockefeller Foundation, Mason had been a physicist at the University of Wisconsin in Madison. He had gotten his Ph.D. from Gottingen, the most famous of the German physics faculties, returning a difficult thesis problem ten days after it was assigned. During World War I, he had done major research on acoustic detection of submarines at the U.S. Navy’s New London, Connecticut, research facility, adapting the Broca tube as the basis of the first workable passive submarine detector. From 1925 to 1928 he was president of the University of Chicago, was named director of natural science at the Rockefeller Foundation in 1928, and president of the foundation the next year.

  Unlike Rose, Mason was a working scientist. He was comfortable with the language and style of scientists, eager and willing to listen to progress reports and to read preprints of forthcoming articles. He also had experience with applied research and the engineering problems that had to be solved to build research instruments. Mason quickly gained the trust of Hale and the other scientists working on the two-hundred-inch project. The feelings were reciprocated. As president of the Rockefeller Foundation, the foundation with the largest role in science, Mason was in a position to deflect the pressures directed at the Pasadena group from astronomers and others eager to take advantage of their acquaintance with foundation officials or trustees.

  As the friendship between Hale and Mason developed, the two men began an exchange of clippings and notes. Grant recipients are usually reluctant to let on too much to foundations, but Hale gradually began to trust Max Mason with even the troublesome news, including the rumors of problems with the one-hundred-inch telescope and Hale’s own doubts about the progress of the mirrors at GE.

  By mid-February 1931, the surfacing of the sixty-inch fused-quartz disk was under way in West Lynn. The early progress reports were good. Hale reported to Max Mason that “our confidence in the ability of Dr. Thomson and Mr. Ellis to solve such problems was not misplaced, and they have now succeeded in making a 60-inch disk 8 inches thick…. There
is every reason to believe that the same process will be successful on a very large scale, and that a 200-inch disk can be manufactured in this way.”

  The news was so promising that Hale proposed a revision to the project budget, shuffling various categories of the $6 million grant around to cover the increased cost of the mirror blanks, and formally proposing that instead of a temporary steel building on the site of the telescope for grinding and figuring the mirror, an optics laboratory could be built on the Caltech campus, adjacent to the machine shop. The advantages of a permanent optics lab had been demonstrated at Santa Barbara Street, where a staff of opticians was kept busy building new instruments and refining old instruments for the big telescopes on Mount Wilson. Having the optics lab next to a machine shop would facilitate the construction and maintenance of the grinding and polishing equipment.

  Hale proceeded carefully, reluctant to ask the Rockefeller executive committee to approve funds for an expensive optics lab before there was some evidence that there would be a mirror to grind.

  Porter was quietly working on plans for the optics lab and for the machines to grind the disks. On this as on so many other aspects of the project, the machines and designs that had worked for smaller mirrors couldn’t be adapted or scaled up. The jump in size and weight from a one-hundred-inch disk to a two-hundred-inch disk meant a shift in both material, from wood to steel, and design, from the crank motion of the older grinding machines to a reciprocating-motion machine that would eliminate the high-torque crank arms and belt drives of the earlier machines. Porter’s design cut the cost of the lab and equipment to half what Pease had once predicted, but it would still be an enormous structure. Hale estimated that at a minimum, the open internal space of a room to grind and polish the disk had to be two hundred feet long, sixty feet wide, and forty feet high, with walls strong enough to carry a fifty-ton traveling crane. The walls and roof would have to be “completely insulated from the heat of the sun” and the lab would need equipment for maintaining a constant temperature inside, as well as the machinery for grinding, polishing, and testing a mirror disk seventeen feet in diameter, weighing thirty tons. The machinery was so large that it would have to be built in place.