Epigraphs
p. ix “Her columns grew longer”: Thomas Mallon, Two Moons (New York: Pantheon, 2000), p. 11.
p. ix “Then, by means of the instrument at hand”: Thomas Hardy, Two on a Tower (New York: Harper & Brothers, 1895), p. 33.
Prologue. The Village in the Canyon
p. 1 As readers shall see in chapter 6, my story about the village in the canyon is elaborated from a comment made by Harlow Shapley in the Great Debate of 1920.
p. 6 The view from Tau Ceti is described on pp. 170–71 of Heinlein’s Time for the Stars (New York: Charles Scribner’s Sons, 1956).
Chapter 1. Black Stars, White Nights
p. 9 “We work from morn till night”: Jones and Boyd, Harvard College Observatory, p. 190. This book and Bailey’s History and Work of the College Observatory are the two standard sources for the early history of the observatory.
p. 9 Computers earned 10 cents more than a cotton mill worker: Pamela Etter Mack, “Women in Astronomy in the United States, 1875–1920” (bachelor’s thesis, Harvard University, 1977). I also referred to her chapter, “Straying from Their Orbits: Women in Astronomy in America,” in Women in Science, edited by Kass-Simon and Farnes, pp. 72–116.
p. 11 an apparatus of leaf springs: Alison Doane, Curator of Astronomical Photographs at the observatory, has told me that her own research cannot confirm this tale. The repository was built in the 1930s.
p. 14 “It is delightful to see the stars brought out”: William Cranch Bond, letter to Harvard President Edward Everett, September 22, 1847, quoted in Jones and Boyd, p. 68.
p. 15 The Great Refractor extended the reach to the fourteenth magnitude: One of the telescope’s first great discoveries, in 1848 by William Cranch Bond and George Bond, was Saturn’s eighth moon, Hyperion, which is between the fourteenth and fifteenth magnitudes.
p. 15 My portrait of Pickering is drawn from Bailey, pp. 243–52, and Jones and Boyd, pp. 178–82.
p. 16 Eventually Harvard measured and cataloged forty-five thousand stars: Jones and Boyd, p. 202. The results were published in 1908 as The Revised Harvard Photometry and appeared in volumes 50 and 54 of the Annals of the Astronomical Observatory of Harvard College.
p. 17 The saga of the observing station at Arequipa is entertainingly described in Fernie’s Whisper and Vision, pp. 153–88. Accounts also appear in Bailey and in Jones and Boyd.
p. 18 “A great observatory should be as carefully organized”: Pickering, in a June 28, 1906, address to the Harvard Chapter of Phi Beta Kappa, Harvard University Archives.
p. 19 25 cents an hour amounted to the minimum wage: Adjusted for inflation, 25 cents in 1900 would be worth $5.27 in 2003. Source: “The Inflation Calculator,” www.westegg.com/inflation.
p. 19 Portraits of Fleming, Cannon, Maury, and other computers appear in Jones and Boyd.
p. 20 The hours and wages of computing are described in Mack, “Women in Astronomy.”
p. 20 “He seems to think that no work”: Williamina Paton Fleming diary, March 12, 1900, in the Harvard archives. (The journal is part of a project in which staff members and students apparently were asked to keep a diary showing what life was like at the university.)
p. 20 Pickering’s handling of Fleming’s request for a raise is documented in his own diary entry for the same date, also in the Harvard archives.
p. 21 Pickering’s salary is found in Jones and Boyd, p. 182. The description of his typical workday is from his diary.
p. 21 The Observatory Pinafore: Jones and Boyd, pp. 189–93. The author of the parody was Winslow Upton.
Chapter 2. Hunting for Variables
p. 23 “My friends say, and I recognize the truth of it”: The letter from HSL to Pickering, dated May 13, 1902, is in the Harvard University Archives.
p. 25 The Leavitt family genealogy is from the excellent database maintained by the Western Association of Leavitt Families at www.leavittfamilies.org, and from information provided by the National Association of Leavitt Families, including a private publication, “Descendants of John Leavitt, the Immigrant, Through His Son, Josiah, and Margaret Johnson,” by Emily Leavitt Noyes (Tilton, N.H., 1949), pp. 83, 105, 133.
p. 25 The description of the Leavitt household on Warland Street (now Kelly Road) is from U.S. Census documents, the Cambridge Historical Commission, Cambridge city directories, and a visit to the house, which still stands. The only record I found of Roswell’s death was the inscription on his gravestone at Cambridge Cemetery.
p. 26 Erasmus Leavitt’s steam engine is described in a pamphlet published by the American Society of Mechanical Engineers, “The Leavitt Pumping Engine at Chestnut Hill Station of the Metropolitan District Commission, Boston, Mass.,” printed in honor of the occasion of its designation as a National Historical Mechanical Engineering Landmark by the American Society of Mechanical Engineers, December 14, 1973.
p. 26 For HSL at Oberlin I relied on alumni records in the college archives. Her time at Radcliffe is documented in her transcript, college catalogs, and other records in the Radcliffe College Archives. The period between Radcliffe and Harvard is described in a one-page alumni questionnaire she filled out for Oberlin on April 6, 1908.
p. 28 “Miss Leavitt inherited, in a somewhat chastened form”: Bailey’s obituary of HSL appeared in Popular Astronomy 30, no. 4 (April 1922), pp. 197–99. (It was followed by an article, “Shall We Accept Relativity?” by William H. Pickering, Edward’s brother.)
p. 30 “an almost religious zeal”: Bailey, History and Work, p. 264.
p. 30 The letters between HSL and Pickering during her stay in Beloit are in the Harvard archives.
p. 31 The short biography in which HSL is called “extremely deaf” at Radcliffe appears in volume 8 of the Dictionary of Scientific Biography, edited by Charles Coulston Gillispie (New York: Charles Scribner’s Sons, 1973).
p. 33 The letter sent from the S.S. Commonwealth and a note from HSL’s brother acknowledging receipt of her paycheck are in the Harvard archives.
Chapter 3. Henrietta’s Law
p. 34 “What a variable-star ‘fiend’ Miss Leavitt is”: The letter, dated March 1, 1905, is from Professor Charles Young at Princeton; it is quoted in Jones and Boyd, Harvard College Observatory, p. 367.
p. 34 “In no other portion of the heavens”: John Herschel is quoted in Shapley’s The Inner Metagalaxy,p.42.
p. 36 “Men said to him, in angry letters”: Reverend Leavitt’s address to the annual meeting of the American Missionary Association was published as “Preaching: The Main Feature in Missionary Work,” The American Missionary 39, no. 3 (March 1885), pp. 76–79. (He mistakenly refers to the astronomer as James Herschel.)
p. 36 HSL’s trip to Europe is documented in a letter from her to Pickering, dated August 4, 1903, in the Harvard University Archives.
p. 37 “an extraordinary number”: From H. S. Leavitt, “1777 Variables in the Magellanic Clouds,” Annals of the Astronomical Observatory of Harvard College 60, no. 4 (1908), pp. 87–108.
p. 37 The Washington Post news brief about HSL appeared January 28, 1906, on p. 4.
p. 37 “the northern star of a close pair”: Leavitt, “1777 Variables”, p. 96.
p. 37 “boarding with Uncle Erasmus”: The Cambridge City Directory lists her at his address, 33 Garden Street.
p. 38 the Astronomical and Astrophysical Society of America: This became the American Astronomical Society in 1914, after a long and acrimonious struggle in which the newer science of astrophysics tried to avoid being subsumed as a branch of astronomy. See “How Did the AAS Get Its Name?” by Brant L. Sponberg and David H. DeVorkin, on the society’s Web site, www.aas.org/~had/name.html. In two letters to Pickering (December 20, 1905, and December 20, 1906), HSL refers to the group simply as the Astrophysical Society.
p. 38 “It is worthy of notice”: Leavitt, “1777 Variables,” p. 107.
p. 38 “It has not escaped our notice”: Watson and Crick’s legendary paper, “Molecular Structure of Nucleic Acids,” appeared in Nature 171 (1953), pp. 737–38.
p. 39 The letters written during HSL’s illness in 1908–1910 are in the Harvard archives. The description of the Leavitt household in Beloit is from census records. That year census takers asked whether anyone in a household was deaf, but the record is ambiguously marked, so it is impossible to tell whether Henrietta was put in that category.
p. 42 Reverend Leavitt’s estate is described in his will (Commonwealth of Massachusetts, probate court records for Middlesex County). Henrietta’s visit home after his death is documented in letters in the Harvard archives.
p. 42 The visit to Des Moines is mentioned in a letter dated July 3, 1911, in the Harvard archives refers to a Mrs. W. G. H. Strong. In June 1901 Henrietta’s sister Martha had married a William James Henry Strong, originally of Council Bluffs, Iowa.
p. 43 “A remarkable relation”: From Edward C. Pickering, “Periods of Twenty-five Variable Stars in the Small Magellanic Cloud,” Harvard College Observatory Circular no. 173 (March 3, 1912). The relationship between period and luminosity is logarithmic.
p. 44 Cepheid yardstick: HSL was clearly aware of the possibilities opened up by her discovery—if the yardstick could be calibrated. As she wrote on the last page of the report, “It is to be hoped, also, that the parallaxes of some variables of this type may be measured.”
Chapter 4. Triangles
p. 45 “I had not thought of making the very pretty use”: Quoted in Smith, The Expanding Universe,p.72.
p. 45 An authoritative source for the history of astronomical parallax is Albert Van Helden’s Measuring the Universe. Good popular accounts include Kitty Ferguson’s book by the same name and Alan W. Hirshfeld’s Parallax. I also relied on two fine histories of astronomy, Arthur Koestler’s The Sleepwalkers and Timothy Ferris’s Coming of Age in the Milky Way.
p. 48 The astronomer who first measured the distance to Mars was Gian Domenico Cassini, director of the Paris Observatory.
p. 49 The Transit of Venus occurs twice a century—but not every century. The transits of 1874 and 1882 were followed by the pair scheduled for 2004 and 2012.
p. 55 Ejnar Hertzsprung’s use of the sun’s motion to triangulate some Cepheids was a bit more complicated than I describe. To determine how much of a star’s change in position is due to solar parallax you must first account for how much it has moved on its own. This can be done with statistical methods similar to those Shapley used to measure the Milky Way (see chapter 5).
p. 55 Hertzsprung’s article appeared in Astronomische Nachrichten 196, pp. 201–10.
p. 56 “that the best service he could render”: Bailey, History and Work,p.25.
p. 56 HSL’s work diary is in the Harvard University Archives.
p. 56 recovering from stomach surgery: HSL’s letter to Pickering, dated May 8, 1913, in the Harvard archives.
p. 57 “It is desirable that the standard scale”: HSL, “The North Polar Sequence,” Annals of Harvard College Observatory 71, no. 3 (1917), p. 230.
Chapter 5. Shapley’s Ants
p. 59 “Her discovery of the relation of period to brightness”: Letter from Shapley to Pickering, September 24, 1917, Shapley correspondence, Harvard University Archives.
p. 59 “It is much more natural and reasonable”: Kant, Allgemeine Naturgeschichte und Theorie des Himmels, published in 1755.
p. 59 Good sources on the early-twentieth-century controversy over the nature of nebulae are Smith’s The Expanding Universe and J. D. Fernie, “The Historical Quest for the Nature of the Spiral Nebulae,” Proceedings of the Astronomical Society of the Pacific 82 (1970), pp. 1189–1230.
p. 60 “No competent thinker”: Quoted in Struve and Zebergs, Astronomy of the Twentieth Century, p. 436.
p. 61 “enveloped and beclouded”: Smith, p. 21.
p. 61 an intrinsic magnitude of about –8: Astronomers knew this because the Doppler effect gave a direct reading of how fast a nova was expanding in the direction of Earth. Comparing that number with how fast the nova appeared to expand revealed the distance, and from the distance one could gauge the intrinsic brightness. Curtis then reversed the procedure, using the hypothesized brightness to estimate the distance of the novae outside the Milky Way.
p. 62 Shapley tells about the ants in his book Through Rugged Ways to the Stars, pp. 65–68.
p. 64 “[T]his proposition scarcely needs proof ”: Harlow Shapley, “On the Nature and Cause of Cepheid Variation,” Astrophysical Journal 40 (1914), p. 449.
p. 66 Shapley’s artful chain of assumptions was developed in nineteen papers each titled “Studies Based on the Colors and Magnitudes in Stellar Clusters”; some of the later ones were coauthored with his wife, Martha, and other co-workers. A full list of citations can be accessed through the Bruce Medalist Web page for Shapley: www.phys-astro.sonoma.edu/BruceMedalists/Shapley. Also see the detailed bibliography in Smith.
p. 66 living alone in a Cambridge rooming house: Actually the Cambridge City Directory lists two: 49 Trowbridge Street and then 49 Dana Street.
p. 66 “Does Miss Leavitt know if they have shorter periods”: Letter from Shapley to Pickering, August 27, 1917, Shapley correspondence, Harvard archives.
p. 66 “Miss Leavitt is now absent on her vacation”: Letter from Pickering to Shapley, September 18, 1917, ibid.
p. 67 “Her discovery of the relation of period to brightness”: Letter from Shapley to Pickering, September 24, 1917, ibid.
p. 67 “I believe the most important photometric work”: Letter from Shapley to Pickering, August 20, 1918, ibid.
p. 67 “A few days ago I talked with Miss Leavitt”: Letter from Pickering to Shapley, September 14, 1918, ibid. Pickering died on February 3, 1919.
p. 68 Van Maanen’s research on the rotation of spiral nebulae was centered on M101, M51, and M33.
p. 69 “So the center has shifted”: Shapley’s letter to Hale, dated January 19, 1918, is quoted in Owen Gingerich, “Shapley’s Impact,” in the Harlow Shapley Symposium on Globular Cluster Systems in Galaxies, Proceedings of the 126th International Astronomical Union Symposium, Cambridge, Mass., August 25–29, 1986 (Dordrecht, Netherlands: Kluwer Academic Publishers, 1988), pp. 23–36.
p. 69 “Man is not such a big chicken”: Shapley, Through Rugged Ways,p. 60.
Chapter 6. The Late, Great Milky Way
p. 70 “The spectrum of the average spiral nebula”: From the slides Curtis used in his 1920 debate with Shapley, Allegheny Observatory Archives, Pittsburgh.
p. 70 The train trip to Washington is described in Shapley, Through Rugged Ways to the Stars, pp. 77–78.
p. 70 The wrangling that took place before the debate is vividly described in Michael A. Hoskin, “The Great Debate: What Really Happened,” Journal for the History of Astronomy 7, pp. 169–82. I also relied on Virginia Trimble’s scholarly and entertaining paper “The 1920 Shapley-Curtis Discussion: Background, Issues and Aftermath,” Proceedings of the Astronomical Society of the Pacific 107 (1995), pp. 1133–44, and on a perceptive analytical account in Smith, The Expanding Universe, pp. 77–86, and Struve and Zebergs, Astronomy of the Twentieth Century, pp. 416–20, 441–44.
p. 71 “to some region of space”: Quoted in Hoskin’s paper.
p. 72 “hammer and tongs”: ibid.
p. 72 “miserable” Cepheids: the letter to Russell is quoted in Smith, p. 81.
p. 73 “noble human antique”: Shapley’s memory of the debate is from Through Rugged Ways, pp. 78–81. As with his story about Einstein, Shapley may have also misremembered these details. The records of the meeting in the archives of the National Academy of Sciences are not detailed enough to tell.
pp. 73–79 In addition to the works mentioned above by Hoskin, Trimble, and Smith, my account of the debate relies on Shapley’s typescript (the original is in the Harvard University Archives) and Curtis’s slides (originals at Allegheny Observatory). Both documents are available at antwrp.gsfc.nasa.gov/diamond_jubilee. The debaters repeated and expanded on their positions in formal papers published in the Bulletin of the National Research Council 2 (1921), pp. 171–93 and 194–217.
p. 79 “Debate went off fine in Washington”: Quoted in Hoskin’s paper. p. 79 “Now I would know how to dodge things”: Shapley, Through Rugged Ways,p.79.
p. 80 “the engulfing of a star”: Shapley, “Globular Clusters and the Structure of the Galactic System,” Publications of the Astronomical Society of the Pacific 30 (1918), p. 53.
p. 80 “Suppose that an observer”: From Shapley’s Bulletin paper.
Chapter 7. In the Realm of the Nebulae
p. 82 “One of the few decent things I have done”: Shapley, Through Rugged Ways to the Stars, p. 91.
p. 82 For biographical details about Shapley, I referred to Through Rugged Ways, as well as the transcript of the oral-history interviews on which the book is based (Charles Weiner and Helen Wright, “Harlow Shapley,” American Institute of Physics, Center for the History of Physics, College Park, Md., June 8, 1966). In addition to serving as my main source on Hubble’s life, Christianson’s Edwin Hubble provided a vivid portrait of Shapley (pp. 129–32).
p. 82 “He is the best student I ever had”: Jones and Boyd, Harvard College Observatory, p. 432, n. 16.
p. 84 “Bah Jove” and “come a cropper”: Shapley, Through Rugged Ways,p. 57.
p. 84 Hubble’s uneasy relationship with Shapley is documented in the books by Christianson and Smith.
p. 85 “the apartment building on Linnean Street”: According to the Cambridge City Directory, HSL and her mother had moved there by 1919. Cambridge Historical Commission records show that the building (3–5 Linnean Street and called Linnean Hall) was built in 1914. Rents ranged from $30 to $52.50 a month.
p. 85 “enormous importance in the present discussion”: Shapley’s letter to HSL, May 22, 1920, is in the Harvard University Archives.
p. 85 Shapley had been overestimating: Owen Gingerich has documented the behind-the-scenes wrangling in “How Shapley Came to Harvard or, Snatching the Prize from the Jaws of Debate,” Journal for the History of Astronomy 19 (1988), pp. 201–7. Also see Hoskin’s “The Great Debate” (cited in the notes for chapter 6).
p. 85 “He is much more venturesome”: Gingerich, “How Shapley Came to Harvard,” p. 203.
p. 86 “Shapley couldn’t swing the thing” : Ibid., p. 204.
p. 86 “So young, so clean, so brilliant”: Cannon’s diary is in the Harvard archives. Details about Cannon and the Shapley era at Harvard Observatory are from Jones and Boyd, Bailey’s History and Work, and Haramundanis’s Cecilia Payne-Gaposchkin, an edition of the astronomer’s memoirs edited by her daughter.
p. 87 “I always wanted to learn the calculus”: Maury said this to Cecilia Payne (Haramundanis, p. 149).
p. 87 “I shall be happy”: Quoted in Jones and Boyd, p. 398.
p. 87 “If one could only go on and on”: Fleming diary, Harvard archives.
p. 88 “She was a pure observer”: Haramundanis, p. 139.
p. 88 “We shall never understand it”: HSL quoted in Haramundanis, p. 140.
p. 88 “Pickering chose his staff to work”: Ibid., p. 149.
p. 88 “one of the most important women”: Shapley, Through Rugged Ways,p.91.
p. 88 “girl-hours” and “kilo-girl-hours”: Ibid., p. 94.
p. 88 “Took flowers to Miss Leavitt”: Cannon diaries, Harvard archives.
p. 90 The details of HSL’s estate are from probate court records for Middlesex County, Massachusetts.
p. 90 What HSL was working on when she died is from the Bailey obituary cited in the notes for chapter 2 and from Harvard University Reports of the President and the Treasurer of Harvard College, 1922–1923: The Observatory, p. 244, Harvard archives.
p. 90 “the famous new star of 1918”: Reports of the President, 1922–1923, p. 244, Harvard archives.
p. 91 “great service to astronomy”: Transactions of the International Astronomical Union 1 (1922), p. 69.
p. 91 “She had hardly begun work”: Reports of the President, 1921–1922, p. 208.
p. 91 For the story of Cecilia Payne and HSL’s desk, see Haramundanis, p. 153.
p. 91 “I heard it said when I came to Harvard”: Ibid., p. 146
p. 92 “Magellanic Cloud (Great) so bright”: Cannon diaries, April 20, 1922.
p. 92 The dispute between Lundmark and Shapley is described in Smith, pp. 105–11.
p. 92 “Whether or not you care to recognize”: Quoted in Smith, p. 106.
p. 93 “On the Motions of Spirals”: Knut Lundmark, Publications of the Astronomical Society of the Pacific 34 (1922), pp. 108–15.
p. 93 Jeans’s analysis of van Maanen’s data is described in Smith, p. 104. Jeans wasn’t opposing the island universe theory. Rather, he thought the Milky Way was considerably smaller than Shapley did. If the spirals were of similar size, they would be much closer to Earth, making the rate of their spin far slower.
p. 93 “the situation seemed to be rather hopeless”: Quoted in Smith, p. 108.
p. 94 An artful account of Hubble’s measurement of Andromeda is in Christianson, pp. 157–62; also see Smith, pp. 111–26.
p. 94 “You will be interested to hear”: Quoted in Smith, p. 114. The correspondence between Hubble and Shapley is divided between the Edwin P. Hubble Manuscript Collection at the Huntington Library in San Marino, Calif., and the Harvard University Archives.
p. 94 “Here is the letter that has destroyed my universe”: Haramundanis, p. 209.
p. 95 “Your letter telling of the crop of novae”: Quoted in Christianson, p. 159.
p. 95 Before he became a professional astronomer, Barnard had earned enough money spotting new comets (a New York philanthropist was paying $200 for each one) to make a down payment on what he called his “comet house.” Today he is best known as the namesake and discoverer of Barnard’s star.
p. 96 “the straws are all pointing” and “I do not know whether I am sorry”: Quoted in Christianson, p. 159.
p. 96 “a curiously faithful copy”: Edwin Hubble, “N.G.C. 6822, A Remote Stellar System,” Contributions from the Mount Wilson Observatory 302 (1925), p. 410.
p. 96 “The principle of the uniformity”: Ibid., p. 432.
p. 97 “a splendid forum”: Quoted in Christianson, p. 160. The AAS/AAAS meeting is described in the same passage. More details are in Popular Astronomy 33, no. 4 (1925), pp. 158–60. An abstract of Hubble’s paper, “Cepheids in Spiral Nebulae,” appeared in the same issue beginning on p. 252.
p. 97 Hubble shared the prize: The other winner of what is now called the Newcomb Cleveland Prize was L. R. Cleveland, whose papers had been read before the American Society of Zoologists.
p. 98 “After all, he was my friend”: Quoted in Haramundanis, p. 209.
p. 98 “assigned subject matter” and “I was right”: Shapley, Through Rugged Ways,p.79.
p. 98 “the realm of the nebulae”: The phrase is used as the title of Hubble’s 1936 book, based on his Silliman lectures at Yale.
p. 98 “What are galaxies?”: Sandage, The Hubble Atlas of Galaxies,p.1.
Chapter 8. The Mysterious K
p. 99 “Youth Who Left Ozark Mountains”: The newspaper headline, which appeared on page 2 of the paper, is quoted in Christianson, Edwin Hubble, p. 210.
p. 99 the Scopes “Monkey Trial”: The Harvard historian of science Owen Gingerich has in his collection a telegram from Darrow inviting Shapley to testify.
p. 102 “with some statistical sleight of hand”: I’m referring here to the technique of statistical parallax, described in chapter 5.
p. 104 For details of Humason’s unusual background see Christianson, pp. 185–86. His work with Hubble is described in Christianson, pp. 192–95, and Smith, The Expanding Universe, pp. 180–83.
p. 105 “twice as large as any hitherto observed”: Milton Humason, “The Large Radial Velocity of N.G.C. 7619,” Proceedings of the National Academy of Sciences 15, no. 3 (March 15, 1929), pp. 167–68.
p. 106 at about 150 kilometers per second: Hubble actually expressed K as 500 parsecs (one parsec being 3.26 light-years). His early results are reported in his paper, “A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebula,” published in the same issue of PNAS as Humason’s paper (pp. 168–73). This was followed in 1931 by Edwin Hubble and Milton Humason, “The Velocity-Distance Relation Among Extra-Galactic Nebulae,” Astrophysical Journal 74, no. 43 (1931), pp. 43–80.
p. 107 “I don’t believe these results”: Quoted in Christianson, p. 198.
p. 107 The encounter between Shapley and Humason is described by Christianson, p. 151. In The Expanding Universe, Smith gives good reasons to believe the story may be true (p. 144, n. 122).
p. 108 Einstein’s calling Hubble’s work “beautiful”: See Christianson, p. 211.
Chapter 9. The Cosmic Stampede
p. 109 “The definitive study of the herd instincts of astronomers”: J. D. Fernie, “The Period-Luminosity Relation: A Historical Review,” Publications of the Astronomical Society of the Pacific 81, no. 483 (December 1969), pp. 719–20.
p. 109 For a detailed account of the controversy over the Milky Way’s seemingly anomalous size, see Smith, The Expanding Universe, pp. 153–56.
p. 110 If these distant spirals were islands: Ibid., p. 154. For a while, Shapley toyed with what he called the Super-Galaxy Hypothesis, in which the Milky Way consisted of a confederation of several smaller galaxies—the globular clusters—bunched together.
p. 111 Trumpler reported his discovery of cosmic dust in his paper “Absorption of Light in the Galactic System,” Publications of the Astronomical Society of the Pacific 42 (1930), pp. 214–27.
p. 113 “most of the astronomers of the day”: Fernie, “Period-Luminosity Relation,” pp. 716–17.
p. 114 Baade gave a nice personal account of how he recalibrated the Cepheid scale—including a description of his conversation with Hubble—in a talk to the Astronomical Society of the Pacific, later published as “The Period-Luminosity Relation of the Cepheids,” Publications of the Astronomical Society of the Pacific 68 (1956), pp 5–16. Christianson provides further details in Edwin Hubble,pp. 291–93.
p. 115 “Instead of one period-luminosity relation”: Baade, p. 11. Along with the cluster variables, he discovered that the Cepheids occasionally found in globular clusters also belonged to Population II.
p. 116 For the revisions to the Hubble constant, see Virginia Trimble, “H0: The Incredible Shrinking Constant, 1925–1975,” Publications of the Astronomical Society of the Pacific 108 (December 1996), pp. 1073–82.
Chapter 10. Ghost Stories
p. 117 “What monsters may they be?”: The passage appears on p. 34 of Hardy’s Two on a Tower.
p. 117 “that Miss Leavitt’s lamp was still to be seen burning”: Haramundanis, Cecilia Payne-Gaposchkin, p. 153.
p. 117 Leavitt’s scant traces: Annie Cannon was, by contrast, quite a pack rat. The Harvard University Archives are stuffed with diaries, guest books, photo albums, letters—nothing, it seems, was discarded. The scant mention these papers make of Henrietta Leavitt make one wonder whether they were even friends.
p. 117 A virtual planetarium: The Henrietta Leavitt Flat Screen Space Theater is located at www.thespacewriter.com.
p. 118 crater on the moon: Harry Lang, “Six Moon Craters Named for Deaf Scientists,” The World Around You, January–February, 1996 (published by Gallaudet University, Washington, D.C.).
p. 118 “The World’s Greatest Creation Scientists” can be found at www.creationsafaris.com. The criteria for compiling the list are so loose that it also includes Sir Francis Bacon, Johannes Kepler, Leonardo da Vinci, William and John Herschel, and even Galileo.
p. 118 “Honoured Miss Leavitt”: Letter from Mittag-Leffler to HSL, February 23, 1925, in Shapley correspondence, Harvard archives.
p. 118 Sonja Kowalewsky: The name also appears in English as Sonya Kovalevskaya. Other variations are Sonja Kowalewski, Sophia Kovalevsky, Sofia Kovalevskaia, and Sofya Kovalevskaya.
p. 119 “Miss Leavitt’s work on the variable stars”: Letter from Shapley to Mittag-Leffler, March 9, 1925, Shapley correspondence, Harvard archives.
p. 119 “The number of variables included in Miss Leavitt’s discussion”: Bailey, History and Work, p. 185.
p. 120 The 1996 “The Scale of the Universe” debate was amply documented in six papers appearing in Publications of the Astronomical Society of the Pacific 108 (December 1996): Jerry T. Bonnell, Robert J. Nemiroff, and Jeffrey J. Goldstein, “The Scale of the Universe Debate in 1996,” pp. 1065–67; Owen Gingerich, “The Scale of the Universe: A Curtain Raiser in Four Acts and Four Morals,” pp. 1068–72; Virginia Trimble, “H0: The Incredible Shrinking Constant, 1925–1975,” pp. 1073–82; G. A. Tammann, “The Hubble Constant: A Discourse,” pp. 1083–90; Sidney van den Bergh, “The Extragalactic Distance Scale,” pp. 1091–96; and John N. Bahcall, “Is H0 Well Defined?” p. 1097.
p. 121 having been Dante’s assistant: Christianson, Edwin Hubble, p. 363.
p. 121 Besides the value of the Hubble constant, other factors affecting the size of the universe include its shape and the value of a parameter called the cosmological constant.
p. 121 The Hubble Wars are described in Overbye, Lonely Hearts of the Cosmos, pp. 263–84.
p. 121 Wonderful maps of clusters and superclusters can be found at www.anzwers.org/free/universe/galaclus.html.
p. 124 corrected by 10 percent: M. W. Feast and R. M. Catchpole, “The Cepheid PL Zero-Point from Hipparcos Trigonometric Parallaxes,” Monthly Notices of the Royal Astronomical Society 286 (1997), L1–L5. More recently, the biggest news about Hipparcos has been a controversy over the accuracy of its triangulation of the Pleiades: X. Pan, M. Shao, and S. R. Kulkarni, “A Distance of 133–137 Parsecs to the Pleiades Star Cluster,” Nature 427 (2004), p. 396.
Epilogue: Fire on the Mountain
p. 130 “With increasing distance, our knowledge fades”: Hubble, Realm of the Nebulae, p. 202.