The Glass Universe

by Dava Sobel

  A cloud darkened Shapley’s horizon in the form of interstellar obscuration. In the spring of 1930, Robert J. Trumpler of the Lick Observatory in California produced proof that the Milky Way teemed with dust. Trumpler, who had once collected ants for Shapley in Australia, now showed that invisible particulates permeated the galaxy. The intruding dust undermined almost all determinations of magnitude, and likewise the distances deduced from magnitudes. Trumpler came to these conclusions by observing one hundred open clusters—close associations of stars that were not as densely crowded together as in globular clusters. He calculated each open cluster’s distance two ways, by its apparent brightness and also its apparent diameter. Both values predictably decreased with distance, but the open clusters faded in brightness much faster than they shrank in size. Some form of “dark matter” definitely intervened to absorb their light. As far as Trumpler could tell, the mysterious absorbing medium was confined to the Milky Way, but unevenly distributed; it concentrated along the plane of the galaxy and dissipated near the poles.

  Shapley had banked on transparency when he estimated the galaxy’s extent at three hundred thousand light-years. With the effect of interstellar absorption factored in, the Milky Way contracted to about half that size. “This was a sharp rebuff to Shapley’s ideas,” Miss Sawyer observed, “and he felt it deeply.” Still he wanted to inform the observatory community of the news. Miss Sawyer said he asked her “to review Trumpler’s paper for a colloquium, knowing, I think, that my empathy for the situation would lead me to deal with it as unabrasively as possible.” That presentation was her last at Harvard. In September she and Frank Hogg got married at her family home in Lowell, Massachusetts, with most of the observatory family as witnesses. The couple set up housekeeping in South Hadley, near their new workplaces—she as assistant to Professor Anne Sewell Young at Mount Holyoke (with time off to write her dissertation on globular clusters), and he as a researcher assigned to the 18-inch telescope at Amherst College.

  Margaret Walton, the Swarthmore graduate and former Pickering Fellow who now served as Miss Cannon’s recorder, married R. Newton Mayall, a landscape architect and amateur variable star observer. She had met him while assisting Margaret Harwood one summer on Nantucket. Miss Walton, however, retained her position at the Harvard Observatory, and also the use of her maiden name.

  Marriage no longer spelled the end of a career for a woman astronomer, as it had when Miss Cannon entered the field. She approved of the new trend, and defended the rights of all her Pickering Fellow brides: “Does it not appear that research, which is not confined to fixed hours or necessarily to office walls, may easily be carried on by married women?” she asked rhetorically in one of her regular reports as chairman of Nantucket’s Astronomical Fellowship Committee. “A stellar photograph may be studied at home, during odd hours, and perhaps may not require more time from a wife or mother than is frequently given to bridge playing or various other social activities.”

  • • •

  SOLON BAILEY SPENT SIX YEARS writing The History and Work of Harvard Observatory, 1839 to 1927. The completed volume was published as a Harvard Monograph early in 1931. Only a few months later, on June 5, Bailey died of a short, sudden illness at his summer home in Norwell. His wife and son were with him. The bereaved Miss Cannon borrowed a line from Julius Caesar for her friend’s obituary: “His life was gentle.” Having known Bailey for thirty years, she could honestly report in the Publications of the Astronomical Society of the Pacific, “He won the respect of all by his wide sympathy, his justice, his never-failing kindness, and his complete lack of self-seeking.”

  Bailey’s other good friend and colleague, Edward King, wrote a separate obituary for publication in Popular Astronomy. Before that story had a chance to appear, however, King himself fell ill and died on September 10, just ten days after he retired. Miss Payne, who had grown close to King through their shared passion for collecting old classical texts, wrote a tribute to him in a subsequent issue of Popular Astronomy. She quoted a letter that King had received from Bailey the previous spring, when both men were reminiscing over their long careers in astronomy: “To have done work which is widely recognized, to have gained the sincere esteem of many and the real love of even a few, surely these are sufficient reasons to look on life as well worth the living.”

  Despite the Depression, Shapley added more than $1 million in gifts and bequests to the observatory’s endowment in 1931, most of it from the Rockefeller Foundation. Construction began in July on a bigger brick building, adjacent to the old one, with all the latest innovations in fireproof protections, plus room for the plate collection’s projected growth over the next fifty years. In October Shapley announced that several of the photographic telescopes would soon move from Observatory Hill to a secluded spot in the woods northwest of Cambridge, near the village of Harvard, Massachusetts. Stands of maple, oak, pine, and birch at the new site, called Oak Ridge, would shelter the instruments from wind, soot, and the plague of artificial light. Shapley also made public his plan to install a 60-inch reflector—a northern counterpart to the one being built for Bloemfontein—at Oak Ridge. The sylvan thirty acres would soon boast the best-equipped observing station in the eastern United States.

  Shapley’s “contributions to astronomical science” had recently won him the National Academy of Sciences medal perpetuating the name of Dr. Henry Draper. The small, elite fraternity of Draper Medal winners included Edward Pickering, George Ellery Hale, Henry Norris Russell, and Arthur Stanley Eddington. Shapley thought the time ripe to add a woman’s name to that roster, and he submitted his nomination in support of Miss Cannon.

  “Her life’s work under the auspices of the Memorial founded by the founder of the medal is drawing to a close,” Shapley wrote to the members of the academy’s Draper Fund Committee. “It is needless to comment on the nature and permanence of her contribution.” She was the one who had put the classification system into its current, popular form, and she alone had passed judgment on each of its quarter million stars. “The Henry Draper Catalogue, as far as I remember, has never received any official recognition in the United States by medal, vote, honorary degree, or otherwise,” Shapley continued. “Miss Cannon is quite indifferent to such recognition; but it strikes me that the work she has done is the greatest contribution to science enabled by the Drapers and that there is a certain appropriateness in considering Miss Cannon for the medal.”

  The committee concurred. Shapley, in his glee, prepared a private citation in advance of the official one yet to come. His read as follows:

  Dr. Annie Jump Cannon

  the benign presence of the Brick Building, noted collector of degrees and medals, author of nine immortal volumes and several thousand oatmeal cookies, Virginia Reeler, bridge player, and the godmother of SW Andromedae, and especially the recipient of the

  Draper Medal of the National Academy of Sciences

  the first medal ever bestowed on a woman by that honorable body of fossils and one of the highest honors attainable by astronomers of any sex, race, religious or political preference—in recognition of this great honor indicated by the Draper Medal and on behalf of the staff of the Harvard Observatory I anoint you with the usual star dust—present you with the metagalactic emblem of good luck—and drape you with this token of becoming the world’s jolliest Draper Medalist.

  CHAPTER FOURTEEN

  Miss Cannon’s Prize

  THE UPCOMING FESTIVITIES AT THE OBSERVATORY promised to be Harlow and Martha Shapley’s biggest party ever: the triennial general assembly of the International Astronomical Union, scheduled for September 1932. When he invited the IAU to Harvard, the director begged to let four years instead of the usual three—just this once—elapse between meetings. The delay would enable an entertainment comparable to that at past receptions in the capitals of Europe, where potentates of church and state had presided over opulent ceremonies. In place of those trappings, the more homespun
Harvard general assembly promised the natural miracle of a total solar eclipse. Shortly before four o’clock local time on Wednesday afternoon, August 31, 1932, the Moon would obliterate the Sun, and the skies over New England would go dark. The visiting astronomers could distribute themselves along the path of totality from Quebec through parts of Maine, Vermont, New Hampshire, and Massachusetts, then pack up their equipment and repair to Cambridge.

  Shapley’s plan entailed a big risk of bad weather. The available predictions gave only a fifty-fifty chance of ideal observing conditions on eclipse day, and failed eclipse expeditions would surely pitch the astronomers into gloom. Even Miss Cannon had turned sour (briefly) when cloud cover cheated her out of photographing the flash spectrum during the 1923 eclipse in southern California. Nevertheless, the director banked on success. He put the first graduate student, Adelaide Ames, now his sidekick in galactic exploration, in charge of hospitality arrangements for the IAU.

  In May 1932, as the time of the assembly neared, Shapley and Miss Ames were wrapping up their extensive, definitive survey of external galaxies. They had looked at more than a thousand island universes contained in the Harvard plate collection. They had classified the shapes of these nebulae, seven hundred of which were spirals, and computed the total brightness of each according to a uniform system of photometric magnitudes. The Shapley-Ames Catalogue showed, for the first time, the distribution of such objects over the entire sky. Although Shapley’s picture of the Milky Way still lacked detail, he and Miss Ames had taken steps toward tracking the contours of the larger cosmos. It was larger than they imagined, and apparently growing larger all the time. As early as 1914, Vesto Melvin Slipher of the Lowell Observatory in Arizona had shown the spectra of most spiral nebulae to be shifted toward the red, meaning they were receding along the line of sight—rushing away at high speed. Later Edwin Hubble at Mount Wilson built on Slipher’s findings. By painstakingly approximating the distances to the fleeing spirals, he perceived a new relationship, dubbed Hubble’s law: the farther the galaxy, the faster it fled.

  In late June, after Miss Ames had left the text and tables of the Shapley-Ames Catalogue with the college printer, she set off with a few of her observatory coworkers for a short vacation at Squam Lake, near Holderness, New Hampshire. The family of her friend Mary Allen owned a rustic lakeside camp there with panoramic views of the White Mountains. On Sunday the twenty-sixth, Miss Ames and Miss Allen paddled a canoe out to the center of the lake, where a squall struck and capsized them. They laughed over the mishap at first, while trying to right the canoe. Then they abandoned ship and swam for shore. Both young women were strong swimmers, but when Mary, in the lead, reached the shallows and looked back over her shoulder, there was no one behind her. She called out to Adelaide a few times. She screamed for help. Others rushed to the scene and made repeated dives at the spot where the hysterical survivor had last seen her companion’s head above water. They could find no sign of her. Someone had to telephone Colonel Thales L. Ames, commanding officer of the Springfield Armory, to inform him that his thirty-two-year-old daughter had apparently suffered a cramp while swimming, and drowned.

  When the news reached Shapley on Monday, he closed the observatory and drove to the lake with Leon Campbell to assist Colonel Ames. Police were there, directing search parties on foot and in small craft. Airplanes skimmed over the lake in circles until dark. On Tuesday Miss Cannon wrote in her diary, “Adelaide’s body not found yet.” It took more than a week to recover her remains. During the funeral service at Christ Church, Cambridge, on July 7, Miss Cannon said it broke her heart to look at Colonel and Mrs. Ames. The following day they buried their daughter—their only child—in Arlington National Cemetery.

  • • •

  THE TRADITIONAL BARRING OF WOMEN FROM CAREERS in most fields of science led, in 1897, to the founding of a small organization centered in Boston called the Association to Aid Scientific Research by Women. In its early years, the group’s sole function was to raise funds in support of a research table for American ladies at the Zoological Station in Naples, Italy, where Professor Anton Dohrn extended a Pickering-esque welcome to female researchers. Within a few years the association broadened its mandate to award grants to individual scientists, and later a prize, the Ellen Richards Research Prize, recognizing lifetimes of accomplishment. The award honored the late Ellen Swallow Richards, a chemist and charter member of the association who had been the first woman admitted as a full-time student to MIT. She established the Women’s Laboratory at the institute in 1876, and, after several years of teaching with neither salary nor title, she became assistant professor of chemical analysis, industrial chemistry, mineralogy, and applied biology. Even then she was given no compensation, but, as a married woman—the wife of Robert Hallowell Richards, head of mining engineering at MIT—she could afford to work without pay.

  The Association to Aid Scientific Research by Women awarded the 1932 Ellen Richards Research Prize of $1,000 to two worthy recipients, Dr. Helen Dean King, a biologist at the Wistar Institute of the University of Pennsylvania, and Dr. Annie Jump Cannon of the Harvard College Observatory. With that decision, the twelve members declared themselves satisfied with the progress they had seen, and they drafted a resolution to dissolve the organization. “Whereas,” it said, “the objects for which this association has worked for thirty-five years have been achieved, since women are given opportunities in Scientific Research on an equality with men, and to gain recognition for their achievements, be it Resolved, that this association cease to exist after the adjournment of this meeting.”

  An outside observer might have judged the association’s dissolution premature. Miss Cannon seemed to think so, as she moved to extend its good works. “Your letter concerning the Ellen Richards Research Prize is of great interest,” she replied to Marjorie Nicolson, dean of students at Smith College, on June 10, 1932, “and the enclosed check is certainly a delightful recognition of my many years of astronomical investigation.” She felt doubly grateful, she said, because she had known the prize’s namesake, and recalled several conversations with Mrs. Richards—at the College Club of Boston and at meetings of the Association of Collegiate Alumnae—concerning opportunities for women.

  “I wish I might convey through you to the Committee,” Miss Cannon continued, “to the donors and to all the members of the former Association to Aid Scientific Research by Women, my very great appreciation of this prize. I hope to use it to advance, in some way, astronomical research by women. Moreover, the very thought of it will be a constant spur for increased efforts on my part towards the completion of the various problems which I have under way, realizing that the faith of so many representative women demands a justification in the highest service which it is possible for one to give.”

  Miss Cannon earmarked her $1,000 bounty to endow the Annie Jump Cannon Prize. She wished it to be awarded biennially or triennially by the American Astronomical Society, to a deserving woman of any nationality. It would take time, she knew, for interest on the seed money to grow into a substantial purse, but she did not want to put off the first award indefinitely. She was nearly seventy years old, and determined to confer the Cannon Prize in person at least once while still in good health. She thought she might enhance the cash value with a feminine token of some kind—a brooch or a necklace in a starry motif, which could be kept as a memento and worn long after the money had been spent. She began searching for a craftswoman who could fabricate the item she had in mind.

  • • •

  NOT ONLY ASTRONOMERS FLOCKED to the Northeast for the total eclipse of August 31, 1932. Wide publicity turned the event into a popular tourist attraction, and although most scientists who made observations were looking at the sky, a few measured the eclipse’s effect on terrestrial phenomena such as radio transmissions and animal behavior. William Morton Wheeler, the Harvard myrmecologist, had read historical reports of ants that ceased all activity during eclipses, as though tr
ansfixed by the sudden midday darkness. Wheeler felt certain the ants were reacting to the rapid drop in temperature, not the absence of light. Eager to learn more, he put out a call for voluntary reports from interested parties.

  “Field observation on insect behavior is, of course, difficult during a total eclipse,” Wheeler conceded in the Proceedings of the American Academy of Arts and Sciences, “because the observer is apt to be very desirous of witnessing at the same time a wonderful astronomical event, which he may never again be able to contemplate.” Still, Wheeler hoped that entomologists would forgo gaping skyward to look down and amass basic information that could be tested further during future eclipses. “Even the astronomers,” he said, “had to learn what to expect during a total eclipse before they could make elaborate preparation beforehand.”

  True to form, astronomers geared up for the occasion. A full boatload of instrumentation from the Royal Observatory, including a 45-foot-long telescope, sailed from Greenwich on July 13, to ensure the accompanying scientists ample time for assembly and practice on-site. Those who planned on just seeing the eclipse, as opposed to observing it, could afford to arrive at the last moment.

  In August a consortium of Canadian astronomers descended on Louiseville, Quebec, to array their instruments on the local fairgrounds, where they encountered the French expedition and the eclipse party of the American Amateur Astronomical Association of New York. All three groups enjoyed optimal conditions and met most of their observing goals during the 101 seconds of totality. Only twenty-five miles to the north at Saint-Alexis-des-Monts, as luck would have it, an equipment-laden encampment that had been set up weeks in advance suffered an invasion of clouds and could not move out from under them. Similarly, a group in Gorham, New Hampshire, reported complete failure due to weather, although four members of that team managed to snatch a clear view of totality through a gap in the clouds by driving thirty miles eastward in a fast car. The other partners stayed put and carried out their fully rehearsed program regardless, on the off chance that the clouds might part in mid-eclipse, though that did not happen. Overall, only a fortunate few of the researchers won the eclipse-day gamble. These included the several Harvard parties, especially the principal one stationed at West Gray, Maine. At a spot near West Acton, Massachusetts, someone noticed a nuptial flight of ants emerging from the soil to mate in midair—a behavior known to be cued by falling temperature.