The Glass Universe

by Dava Sobel

  Arthur Searle (October 21, 1837–October 23, 1920) served at the observatory for fifty-two years, including a period as acting director after Joseph Winlock died. He assisted Pickering in photometry, and taught astronomy classes at Radcliffe.

  Harlow Shapley (November 2, 1885–October 20, 1972), the fifth director, from 1921 to 1952, added graduate education to the observatory’s mission. Using Cepheid variables and the period-luminosity relation, he showed the Sun to be far from the center of the Milky Way, contrary to previous belief.

  Martha Betz Shapley (August 3, 1890–January 24, 1981), “first lady” of the observatory, earned three degrees from the University of Missouri (B.S. in Education, 1910; A.B., 1911; M.A., 1913) before continuing Latin studies and German philology at Bryn Mawr. Her math ability enabled her to compute everything from the orbits of eclipsing binaries to the trajectories of ballistics for the U.S. Navy during World War II.

  Winslow Upton (October 12, 1853–January 8, 1914) assisted only two years at Harvard before moving on to the U.S. Naval Observatory, the U.S. Signal Service, and Brown University, but he captured the 1877–1879 atmosphere in his spoof The Observatory Pinafore.

  Arville D. Walker (August 2, 1883–August 5, 1963) joined the staff following her 1906 graduation from Radcliffe. In addition to work on variable stars and light curves of novae, she served as Harlow Shapley’s secretary and a trusted adviser to the younger women at the observatory.

  Margaret Walton (later Mayall) (January 27, 1902–December 6, 1995) cooperated closely with Annie Cannon on stellar classification, and completed the work on the Henry Draper Extension that had been left unfinished at Miss Cannon’s death. She joined a special weapons group at MIT during World War II, and later served as Pickering Memorial Astronomer with the American Association of Variable Star Observers.

  Oliver Clinton Wendell (May 7, 1845–November 5, 1912) assisted Edward Pickering for more than thirty years of photometry studies, paying particular attention to the changing light of variable stars.

  Fred Lawrence Whipple (November 5, 1906–August 30, 2004), a comet expert, joined the Harvard Observatory in 1931 and became director of the Smithsonian Astrophysical Observatory in 1955. His contributions include the first tracking network for artificial satellites and the Whipple shield to protect spacecraft from damage by meteors.

  Sarah Frances Whiting (August 23, 1847–September 12, 1927) learned from Edward Pickering how to set up a practical physics laboratory, and established one at Wellesley College, where she taught and inspired Annie Jump Cannon.

  Harvia Hastings Wilson (December 23, 1900–May 4, 1989), a 1923 Vassar alumna, delayed the start of her graduate studies till 1924 because of illness. At Harvard she studied the Magellanic Clouds, but returned to Vassar in 1925 as a physics instructor, then married accountant Hubert Stanley Russell in 1927.

  Anna Winlock (September 15, 1857–January 3, 1904), eldest child of Joseph and Isabella Winlock, accompanied her father to Kentucky for the total solar eclipse of 1869, and started her thirty-year career as a Harvard computer shortly after his death.

  Joseph Winlock (February 6, 1826–June 11, 1875) worked as a computer for—and later superintended—the American Ephemeris and Nautical Almanac. Appointed as third observatory director in 1866, he devoted himself to improving the existing instruments and acquiring new ones.

  Frances Woodworth Wright (April 30, 1897–July 30, 1989) came to Harvard in 1928, after teaching at Elmira College. During World War II she taught celestial navigation to U.S. Navy officers and also wrote a book on the subject. After earning her Radcliffe Ph.D. in astronomy in 1958 under Fred Whipple’s supervision, she continued working until 1971.

  Anne Sewell Young (January 2, 1871–August 15, 1961) earned a doctorate in astronomy from Columbia University and taught at Mount Holyoke for thirty-seven years. She took eight hundred students, including Helen Sawyer, from Smith and Mount Holyoke by train to see the January 1925 total solar eclipse in Windsor, Connecticut.

  REMARKS

  Preface

  In its early years, the Harvard Observatory was often called the “Observatory at Cambridge.” Its official naming in 1849 as the “Astronomical Observatory of Harvard College” set it apart from a meteorological observatory—and preserved the word college, even though Harvard, founded in 1636, had been recognized as a university since 1780.

  The observatory’s first home was at Dana House in Harvard Yard, but it moved in 1844 to Summerhouse Hill, which name gradually changed to Observatory Hill.

  The first instruments of the Harvard College Observatory were those belonging to William Cranch Bond as his personal property.

  CHAPTER ONE: Mrs. Draper’s Intent

  Mrs. Draper’s full first name was Mary Anna, but she always signed herself as Anna Palmer Draper.

  Dr. John William Draper, Henry’s father, took the first photograph of the Moon, in 1839, and also, in 1840, one of the first photographic portraits made with sunlight. The subject was his sister Dorothy Catherine.

  Scientists responded enthusiastically in 1877 to Dr. Henry Draper’s detection of bright oxygen lines in the Sun’s spectrum, but opposition arose within the year, especially among British observers such as Norman Lockyer. The main purpose of the Drapers’ trip to England in 1879, when they visited William and Margaret Huggins, was to gain Henry an audience before the Royal Astronomical Society. After that presentation, he conducted additional research to defend his discovery, but died before announcing any further results. Controversy continued until 1896, when German physicists Carl Runge and Friedrich Paschen conclusively identified oxygen in the solar spectrum via dark Fraunhofer lines—not the bright lines that Draper had mistaken for proof.

  Polaris later proved to be (slightly) variable. In 1911 the Danish astronomer Ejnar Hertzsprung detected a 0.14 magnitude change over not quite four days. Polaris is now known to be a multiple system made up of three component stars (one giant and two dwarfs).

  CHAPTER TWO: What Miss Maury Saw

  As Earth rotates daily and revolves annually, its north-south axis wobbles slowly over millennia, completing a full cycle every twenty-six thousand years. As a result, the star that serves as a “polestar” changes over time. Our present North Star, Polaris, has no counterpart in the Southern Hemisphere.

  Earth’s wobble, called precession, changes the right ascension and declination of the stars by roughly one degree per century. Therefore nineteenth-century star catalogues gave stellar positions for a particular “epoch” date, such as 1875.0. Observations made in non-epoch years—1885, for example—were reduced (corrected by calculation) to 1880.0 or 1890.0.

  Most of the naked-eye stars have individual names granted to them in the Middle Ages by Arabic astronomers, such as Altair for the brightest star in the Eagle, and Vega for the brightest in the Lyre. In the early seventeenth century the German astronomer Johann Bayer introduced a naming system using Greek letters, so that Vega was designated Alpha Lyrae, its next brightest constellation companion Beta Lyrae, and so on down the Greek alphabet as far as necessary. Although the Arabic star names persist in the West, Babylonian, Indian, Chinese, and other cultures’ names have also adhered to the stars since antiquity.

  John William Draper (1811–1882) met and married Antonia Coetana de Paiva Pereira Gardner (1814–1870) while visiting his relatives in England. The couple had six children: John Christopher (1835–1885), Henry (1837–1882), Virginia (1839–1885), Daniel (1841–1931), William (1845–1853), and Antonia (1849–1923). Dorothy Catherine Draper (1807–1901), whose self-sacrifice had facilitated her brother’s education, also helped raise his children, as her sister-in-law was often ill. When Dorothy was thirty-two she had a serious suitor, but John William opposed the match, and she never married.

  Antonia Maury’s full name was Antonia Coetana de Paiva Pereira Maury. The de Paiva and Pereira families were Brazilian forebears of her grandmother Antoni
a Coetana de Paiva Pereira Gardner (Mrs. John William Draper).

  Hermann Carl Vogel (1842–1907) of Germany independently discovered spectroscopic binaries at the same time as Edward Pickering. From his studies of spectra to gauge the motions of stars along the line of sight, Vogel showed that Algol and Spica each had an unseen companion.

  Zeta Ursae Majoris, also known as Mizar, was split by telescope into two stars, Mizar A and B, photographed by George Bond in 1857. In 1889 Edward Pickering saw Mizar A itself as a pair—the first to be discovered by spectroscopy. Later, Mizar B also proved to be a binary pair.

  CHAPTER THREE: Miss Bruce’s Largesse

  The $50,000 gift from Miss Bruce would equal well over $1 million in today’s currency.

  No portrait of Miss Bruce exists, as far as I can tell. Some searches turn up a handsome full-length portrait of a lady in a fur-trimmed yellow dress, but this is her cousin Catharine Lorillard Wolfe, also an heiress and a generous patroness of New York’s Metropolitan Museum of Art.

  Portraits of all the observatory directors hang on the walls at Harvard—all except for George Phillips Bond. Although he was a photography pioneer, he never had his own photograph taken or his likeness painted.

  CHAPTER FOUR: Stella Nova

  A nova, long thought to be a “new star,” is now understood as the flaring of an ancient star in a binary system. The old star has exhausted its own fuel, but pulls in hydrogen from its companion. When enough hydrogen accumulates on the surface, an explosion of runaway fusion occurs to make the body suddenly visible. This can happen many times in a star’s life. The objects observed by Tycho, Galileo, and Kepler are now classified as supernovae, or the end-stage catastrophic explosions of stars far more massive than our Sun. Since such an event destroys the star, the supernova phenomenon does not repeat.

  Antonia Maury’s sister Carlotta (1874–1938) attended Radcliffe College and Cornell and Columbia universities, and earned a doctorate in geology from Cornell in 1902. She traveled widely as a paleontologist, making numerous field trips to Brazil, Venezuela, South Africa, and several islands of the Caribbean. Another sister, Sarah, born in 1869, died in childhood. Their brother, John William Draper Maury (1871–1931), called Draper in his youth, attended Harvard and became a physician. He later dropped the name Maury.

  CHAPTER FIVE: Bailey’s Pictures from Peru

  The founding of the Astronomical Society of the Pacific in February 1889 was a direct outcome of the previous month’s eclipse. Staff members from the Lick Observatory and amateur astronomers and photographers in California enjoyed excellent viewing conditions and expedition results. They created an organization that remains a congenial mixture of professionals and amateurs, having grown from forty to six thousand members. The first woman admitted to membership was Rose O’Halloran, in 1892.

  At first, the U.S. national professional organization of astronomers had no name. Hale very much wanted “astrophysics” to be part of the group’s identity, and so it became the Astronomical and Astrophysical Society of America in 1899. As time passed, the name seemed unnecessarily unwieldy, especially as astrophysics came to dominate all of astronomy, and was changed to the American Astronomical Society in 1914.

  Aristarchus, lacking good observational instruments, underestimated the distances to the Sun and Moon. The Sun is not twenty but fully four hundred times farther from Earth than the Moon.

  CHAPTER SIX: Mrs. Fleming’s Title

  Edward Pickering also wrote a contribution for the “Chest of 1900,” detailing his daily activities at the observatory as well as his leisure pursuits. In summers, he said, he liked to take long bicycle rides of twenty or thirty miles, two or three times a week. Since wheeling was his only exercise, he admitted that he suffered in the winter when he rode infrequently. On cloudy evenings Mrs. Pickering often read to him from a novel. The two of them enjoyed playing chess together.

  The anonymous gift of 1902 came from Henry H. Rogers of Standard Oil.

  The asteroid Eros occasioned another worldwide observing campaign in 1975. The potato-shaped body is now known to rotate every five hours and has a varied composition that accounts for its changeable brightness.

  CHAPTER SEVEN: Pickering’s “Harem”

  William H. Pickering claimed to have discovered a tenth satellite of Saturn in April 1905, and named it Themis, but it has yet to be confirmed.

  CHAPTER EIGHT: Lingua Franca

  Astronomer Friedrich Wilhelm Bessel announced the first successful distance measurement to a star, 61 Cygni, in 1838. He chose the star for its large proper motion, which suggested comparative nearness, then observed it along two different lines of sight. Just as a finger held in front of the face will appear to jump with respect to background objects when viewed first with one eye and then the other, a relatively close star will shift against the background stars when viewed at six-month intervals from opposite points in Earth’s orbit (a baseline of two astronomical units). Bessel measured the star’s angle of displacement, called parallax, and expressed the stellar distance in astronomical units, which translated to about ten light-years. It was a triumphant achievement. However, since stellar parallax angles are tiny, the method carries stellar distance measurements only so far—no more than a few hundred light-years from the Sun.

  CHAPTER NINE: Miss Leavitt’s Relationship

  As Annie Jump Cannon, Antonia Maury, Henry Norris Russell, and others suspected, the various color categories in the Draper classification are indeed associated with specific stages in the lives of stars. Astronomers now know that only the most massive stars begin life in bright blue or white; as a consequence of burning so brightly, they burn out much faster than lower-mass stars such as the Sun. Our Sun, a G-type star, has existed for some five billion years and shines yellow, indicating a surface temperature of about six thousand degrees. In another few billion years, when it has converted most of its hydrogen to helium, the Sun will expand in diameter but cool at the surface, becoming a red giant M star. Other changes will ultimately render it a nonluminous “white dwarf.”

  CHAPTER TEN: The Pickering Fellows

  The study of Cepheid variables affected areas of astrophysics beyond cosmic distances. Attempts by Arthur Stanley Eddington and others to explain what factors would make a star pulsate led, eventually, to an understanding of the structure, behavior, and longevity of stars in general.

  CHAPTER ELEVEN: Shapley’s “Kilo-Girl” Hours

  The Nantucket Maria Mitchell Association chose Fiammetta Wilson as the 1920–1921 Edward C. Pickering Fellow, but she fell ill and died in July 1920 before learning of the award, which went instead to her colleague A. Grace Cook.

  Two capital letters at the start of a star name, such as SW Andromedae, identify that star as a variable. Stars that were named before anyone demonstrated their variability, such as Delta Cephei, retain their original names.

  CHAPTER TWELVE: Miss Payne’s Thesis

  The first woman to pursue advanced study in astronomy was Dorothea Klumpke, a native of San Francisco who conducted research on the rings of Saturn and earned a doctor of science degree at the University of Paris in 1893. Remaining in Europe, she worked for the French Bureau of Measurements and married English amateur astronomer Isaac Roberts.

  The first woman to earn a Ph.D. in astronomy in the United States was Margaretta Palmer (1862–1924), at Yale, in 1894. A Vassar classmate of Antonia Maury’s, she wrote her thesis on the orbit of Comet 1847 VI—the one discovered by her professor, Maria Mitchell. Dr. Palmer had been working at Yale as a computer before starting graduate studies, and stayed on the staff until her death.

  The Henry Draper Extension, published in six installments between 1925 and 1936, added roughly another fifty thousand spectral classifications of faint stars to the quarter million given in the nine-volume Henry Draper Catalogue.

  CHAPTER THIRTEEN: The Observatory Pinafore

  T
he Harvard-Radcliffe Gilbert & Sullivan Players gave an abridged concert performance of The Observatory Pinafore at the American Academy of Arts & Sciences in Cambridge on October 26, 2000, as part of a banquet and centenary symposium honoring Cecilia Payne-Gaposchkin.

  The so-called dark matter demonstrated by Robert Trumpler’s research was interstellar dust. It should not be confused with the mysterious invisible entity given the same name by modern astronomers, who believe dark matter is what holds galaxies together.

  CHAPTER FOURTEEN: Miss Cannon’s Prize

  After Harlow Shapley announced the wedding of Cecilia Payne and Sergei Gaposchkin, Miss Cannon made a note on the appropriate page in her diary. This particular diary was of the five-year variety, with room for only a paragraph-length entry per date, and in the allotted box she had already recorded how water pouring in through the back wall had flooded the cellar to a depth of several inches (though whether at her home or the observatory she did not specify). She had also mentioned teaching a class about the observatory’s early history. Now, writing at a slant in the right-hand margin alongside these March 5 events, she added the news: “C.H.P. and S.G. married at Municipal Chapel, N.Y.”

  CHAPTER FIFTEEN: The Lifetimes of Stars

  Beta Lyrae’s orbital elements were computed completely and successfully for the first time in 2008. The component stars are so close together that the task remained impossible till this late date. Nearly one thousand Beta Lyrae–type variables are now known.

  Many former members of the Harvard Observatory staff are interred in Cambridge, at the Mount Auburn Cemetery. It is a beautiful spot, as much an arboretum as a burial ground. Since the astronomers’ graves are randomly distributed throughout the grounds, the cemetery office provides a map, with each relevant plot marked by a star. The Bond family members are reunited at Mount Auburn, as are the King family and the Bailey family, including Solon and Ruth’s second son, Chester Romaña Bailey, only three months old when he died in August 1892. The Baileys were back in New England then, fresh from their first assignment in Peru, and the child’s middle name honored good friends they had made in Arequipa.