Adriaan Van Maanen's Influence on the Island Universe Theory: Part 2

Letter, Campbell W. W. to Slipher V. M. , 9 April 1913 (Lowell Observatory Archives).

Letter, Miller J. A. to Slipher V. M. , June 1913 (Lowell Observatory Archives).

Letter, Hertzsprung E. J. to Slipher V. M. , 14 March 1914 (Lowell Observatory Archives).

Slipher V. M. , “The Radial Velocity of the Andromeda Nebula”, Lowell Observatory bulletins, ii (1913), 56–57.

The talk was later published: “Spectroscopic Observations of Nebulae”, Popular astronomy, xxiii (1915), 21–24.

A direct quotation of his comments is given in: Hall John S. , “Vesto Melvin Slipher (1875–1969)”, Yearbook of the American Philosophical Society (1970), 165.

“Dr. V. M. Slipher Tells of Inconceivable Distance of Dreyer Nebula No. 584”, The New York Times, 19 January 1921, p. 6.

See ref. 50. For a more detailed discussion see Hetherington N. S. , “The Measurement of Radial Velocities of Spiral Nebulae”, Isis, lxii (1971), 309–13.

Slipher V. M. , “The Detection of Nebular Rotation”, Lowell Observatory bulletins, ii (1914), 66. He had mentioned it in the talk at the A.A.S. meeting in August 1914.

Pease F. G. , “The Rotation and Radial Velocity of the Spiral Nebula N.G.C. 4594”, Proceedings of the National Academy of Sciences, ii (1916), 517–21; Publications of the Astronomical Society of the Pacific, xxviii (1916), 191.

Pease F. G. , “The Rotation and Radial Velocity of the Central Part of the Andromeda Nebula”, Proceedings of the National Academy of Sciences, iv (1918), 21–24.

Letter, Stebbins J. to Curtis H. D. , 22 January 1924 (Allegheny Observatory Archives).

Letter, Curtis H. D. to Stebbins J. , 27 January 1924 (Allegheny Observatory Archives).

Ibid.

Letter, Slipher V. M. to Curtis H. D. , 10 June 1924 (Lowell Observatory Archives).

Letter, Curtis H. D. to Burnt W. H. , 20 January 1922 (Allegheny Observatory Archives).

Letter, Curtis H. D. to O'Dea P. , 5 July 1924 (Allegheny Observatory Archives).

Hubble E. P. , “The Direction of Rotation in Spiral Nebulae”, Astrophysical journal, xcvii (1943), 112–18.

The details of that announcement and insight into van Maanen's influence on Hubble are given in: Berendzen R. and Hoskin M. , “Hubble's Announcement of Cepheids in Spiral Nebulae”, Leaflets of the Astronomical Society of the Pacific, June 1971; Hoskin M. A. , “Edwin Hubble and the Existence of External Galaxies”, Paper delivered at the XII^e Congrès International d'Histoire des Sciences, Paris 1968. Hubble's paper was given at a joint session of the American Association for the Advancement of Science and of the American Astronomical Society.

Letter, Curtis H. D. to Aitken R. G. , 2 January 1925 (Lick Observatory Archives).

For more biographical information on Slipher, see: Ref. 51; Hall J. S. , “V. M. Slipher's Trailblazing Career”, Sky and telescope, xxxix (1970), 84–86; Hart R. and Berendzen R. , “V. M. Slipher”, Dictionary of scientific biography (in press).

Jeans considered spirals to be merely one stage in an evolving nebula. He believed that an initially-spherical mass of gas in rotation would flatten as it contracted and eventually become unstable, ejecting material in filaments from its edges, thereby forming spiral arms. See, for example, Problems of cosmogony and stellar dynamics (Cambridge, 1919).

Letter, van Mannen A. to Shapley H. , 22 June 1921 (Harvard University Archives).

Letter, van Maanen A. to Shapley H. , 17 August 1921 (Harvard University Archives).

“Internal Motions in Four Spiral Nebulae”, op. cit. (ref. 22), 200.

Ibid., 202.

For a more detailed discussion see: Hart R. and Berendzen R. , “Hubble's Classification of Non-Galactic Nebulae, 1922–1926”, Journal for the history of astronomy, ii (1971), 109–19.

Jeans J. , “Internal Motion in Spiral Nebulae”, Observatory, xl (1917), 60–61.

“Proceedings at the Meeting of the Royal Astronomical Society”, Observatory, xliv (1921), 353.

Ibid., 355.

Eddington A. S. , “The Motions of Spiral Nebulae”, Monthly notices of the Royal Astronomical Society, lxxvii (1917), 375–7, p. 377.

Reynolds J. H. , “Nebulae”, Monthly notices of the Royal Astronomical Society, lxxxiv (1924), 283–6, p. 285.

Jeans J. H. , “Internal Motions in Spiral Nebulae”, Monthly notices of the Royal Astronomical Society, lxxxiv (1923), 60–76, p. 60.

Ibid.

Ibid., 67.

Ibid., 72. It should be noted that the temper of the times was highly suitable for such an apparently radical proposal, for it followed two of the most revolutionary decades in science. Unconventional proposals in physics were becoming commonplace.

Ibid., 76.

Jeans J. H. , “Note on the Distances and Structure of the Spiral Nebulae”, Monthly notices of the Royal Astronomical Society, lxxxv (1925), 531–4, p. 531.

These notes were also attached to a letter from Jeans J. H. to Russell H. N. , 23 October 1924 (Princeton University Archives). This, incidentally, provides proof of the widespread dissemination of knowledge of Hubble's discovery before the public announcement of the work at AAS Washington meeting in December 1924. Further details can be found in the papers in ref. 64. Although Jeans had to give up dependence on van Maanen as an observational champion of his own work, he soon found another in Hubble. Hubble's work on the classification of galaxies was adopted by Jeans as the observational evidence for his work (see ref. 72).

Reynolds J. H. , “Nebulae”, Monthly notices of the Royal Astronomical Society, lxxxvi (1926), 257–9, p. 258.

Brown E. W. , “Gravitational Forces in Spiral Nebulae”, Astrophysical journal, lxi (1925), 97–113.

Brown E. W. , “Gravitational Motion in a Spiral Nebula”, Observatory, li (1928), 277–86, p. 278.

Lampland C. O. , “On the Proper Motion of the Virgo Nebula, NGC 4594”, Popular astronomy, xxii (1914), 631–2.

Lampland C. O. , “Preliminary Measures of the Spiral Nebulae NGC 5194 (M51) and NGC 5254 (M99) for Proper Motion and Rotation”, Popular astronomy, xxiv (1916), 667–8.

Lampland C. O. , “On Changes Observed in the Nucleus of the Spiral Nebula NGC 4254 (Messier 99)”, Publications of the Astronomical Society of the Pacific, xxxiii (1921), 167–8.

Letter, Shapley H. to van Maanen A. , 17 May 1921 (Harvard University Archives). Shapley must have had private correspondence with Lampland since Lampland's paper (ref. 90) was dated 18 May.

By 1921, Curtis and Lundmark were almost alone in openly opposing van Maanen. Not only did van Maanen have Shapley, Russell and Jeans on his side, but also much of the rest of the astronomical community. After returning from a meeting (probably A.A.S.), Shapley wrote to van Maanen (8 September 1921, Harvard University Archives): I think that your nebular motions are taken seriously now, and nobody but Very dared raise his head after I explained how dead the island universes are if your measures are accepted. And he later came around.

Letter, van Maanen A. to Shapley H. , 23 May 1921 (Harvard University Archives).

Letter, Hubble E. P. to Slipher V. M. , 24 July 1923 (Lowell Observatory Archives).

Kostinsky S. , “Probable Motions in the Spiral Nebula Messier 51 (Canes Venatici) Found with the Stereo-comparator, Preliminary Communication”, Monthly notices of the Royal Astronomical Society, lxxvii (1917), 233–4.

Schouten W. J. A. , “Probable Motions in the Spiral Nebula Messier 51 (Canes Venatici)” Observatory, xlii (1919), 441–4.

Op. cit. (ref. 33), 275.

Curtis H. D. , Lick Observatory Report, 1 July 1913–15 May 1914 (Lick Observatory Archives).

Curtis H. D. , “Proper Motions of the Nebulae”, Publications of the Astronomical Society of the Pacific, xxvii (1915), 214–18; “Preliminary Note on Nebular Proper Motions”, Proceedings of the National Academy of Sciences, i (1915) 10–12.

Ibid., 12.

It is possible that at the time van Maanen did not understand the implication of what he had found. A. Joy, who knew van Maanen well at both Yerkes and Mt Wilson, recently stated that van Maanen never mentioned the findings to him, “probably because at first he did not realize their significance” (private communication, 24 April 1972).

Op. cit. (ref. 3), 214; emphasis in original.

Curtis H. D. , “The Nebulae”, The Adolpho Stahl Lectures in Astronomy (San Francisco, 1917), 95–107.

Letter, Curtis H. D. to Campbell W. W. , 11 July 1922 (Lick Observatory Archives); emphasis in original.

Ibid., emphasis in original.

Letter, van Maanen A. to Campbell W. W. , 9 June 1922 (Lick Observatory Archives).

Letter, Campbell W. W. to Curtis H. D. , 12 June 1922 (Lick Observatory Archives).

Letter, Lundmark K. to Campbell W. W. , 13 June 1922 (Lick Observatory Archives).

Letter, van Maanen A. to Russell H. N. , 1 August 1922 (Princeton University Archives).

Letter, Curtis H. D. to van Maanen A. , 28 January 1925 (Allegheny Observatory Archives); emphasis in original.

Letters of Curtis H. D. to Merrill R. , 8 January 1925; to Shoek , 24 March 1925; to Kaftiner S. , 12 April 1925 (Allegheny Observatory Archives). Also, he wrote to W. M. Smart in England (see ref. 85) on 13 May 1924 pointing out the apparent contradiction in direction of rotation and asking the “‘mathematical sharks’ on the other side of the water” to consider the difficulty (Allegheny Observatory Archives). Smart was an enthusiastic supporter of van Maanen's results, as he had recently stated in a lengthy paper: “The Motions of Spiral Nebulae”, Monthly notices of the Royal Astronomical Society, lxxxiv (1924), 333–53. In the early 1920s the most prominent astrophysicists in the world were Eddington A. S. and Jeans J. H. , both Englishmen. Consequently, England was the principal centre of influence in theoretical astronomy.

Curtis H. D. “The Nebulae”, Handbuch der Astrophysik, v (Berlin, 1933), 774–936.

Lundmark K. , “The Spiral Nebula Messier M33”, Publications of the Astronomical Society of the Pacific, xxxiii (1921), 324–7.

Lundmark K. , “The Proper Motions of Spiral Nebulae”, Popular astronomy, xxx (1922), 623.

Lundmark K. , “On the Motions of Spirals”, Publications of the Astronomical Society of the Pacific, xxxiv (1922), 108–15.

Ibid., 109.

Letter, Lundmark K. to Aitken R. G. , 31 May 1924 (Lick Observatory Archives).

Lundmark K. , “Internal Motions of Messier 33”, Astrophysical journal, lxiii (1926), 67–71, p. 67.

Op. cit. (ref. 38), 80–81.

Jeans J. H. , Astronomy and cosmogony (Cambridge, 1928), 351.

Lundmark K. , “Studies of Anagalactic Nebulae: First Paper”, Upsala Astronomiska Observatorium Meddilanden, No. 30 (1927), 48–49; emphasis in original.

Op. cit. (ref. 31). The attack was probably in response to Lundmark's criticisms in his 1922 paper (ref. 115).

Lundmark's original statements about spirals are included in his exhaustive dissertation: “The Relations of the Globular Clusters and Spiral Nebulae to the Stellar System”, Kungl. Svenska Vetenskapsakademiens Handlingar, lx (1920), 1–79. Van Maanen criticized Lundmark's assumption that spirals are comparable with the Milky Way and the Magellanic clouds; he asserted that this was tantamount to begging the question.

Op. cit. (ref. 31), 216.

It is possible that Lundmark could have discussed qualitative agreement with van Maanen before returning to Upsala.

Op. cit. (ref. 33), 278.

Letter, Hubble E. P. to Russell H. N. , 19 February 1925 (Princeton University Archives). Hubble made essentially the same statement in a letter to Stebbins on 6 March 1925 (Niels Bohr Library, American Institute of Physics).

For details see Fernie J. D. , “The Period-Luminosity Relation: A Historical Review”, Publications of the Astronomical Society of the Pacific, lxxxi (1969), 707–31.

Op. cit. (ref. 33), 274.

Ibid., 275.

van Maanen A. , “Investigations on Proper Motion, Eleventh Paper: The Proper Motion of Messier 13 and its Internal Motion”, Astrophysical journal, lxi (1925), 130–6.

van Maanen A. , “Investigations on Proper Motion, Twelfth Paper: The Proper Motions and Internal Motions of Messier 2, 13, and 56”, Astrophyscial journal, lxvi (1927), 89–112, p. 89.

A summary of the meeting can be found in Monthly notices of the Royal Astronomical Society, lxxxv (1925), 897–903.

The discovery of the velocity-distance relation by Hubble in 1929, which fitted so well with the theoretical considerations of de Sitter and others, obviously required spirals to be distant.

van Maanen A. , “Investigations on Proper Motion, Fifteenth Paper: The Proper Motion of the Spiral Nebula NGC 4051”, Mt Wilson Contributions No. 407 (1930), 1–6.

Letter, Merrill P. W. to Curtis H. D. , 2 November 1924 (Allegheny Observatory Archives). It is unfortunate for the historian that both Hubble and van Maanen worked at Mt Wilson, for no correspondence between them seems to exist. But according to Shapley (ref. 38), they never liked one another; thus they might not have communicated under any condition.

Letter, Aitken R. G. to Curtis H. D. , 26 January 1925 (Allegheny Observatory Archives).

Letter, Russell H. N. to Hubble E. P. , 12 December 1924 (Henry E. Huntington Library, San Marino, California).

Letter, Russell H. N. to Davis W. , 12 December 1924 (Princeton University Archives).

Russell H. N. , “The Nebulae”, Lectures at the University of Toronto, February 1924 (unpublished transcript in the Princeton University Archives).

Op. cit. (ref. 112), 851.

van Maanen A. , “Investigations on Proper Motion, Sixteenth Paper: The Proper Motion of Messier 51, NGC 5194”, Mt Wilson Contribution No. 408 (1930), 1–4.

Op. cit. (ref. 135), 6.

Hubble E. P. , “NGC 6822, A Remote Stellar System”, Astrophysical journal, lxii (1925), 409–33; “A Spiral Nebula as a Stellar System: Messier 33”, Astrophysical journal, lxiii (1926), 236–74; “A Spiral Nebula as a Stellar System, Messier 31”, Astrophysical journal, lxix (1929), 103–57.

Hubble E. P. , “Angular Rotations of Spiral Nebulae”, Astrophysical journal, lxxxi (1935), 334–5. Drafts by Hubble of much longer papers remain in manuscript; one of these is dated 1932 (Henry E. Huntington Library, San Marino, Calif).

van Maanen A. , “Internal Motions in Spiral Nebulae”, Astrophysical journal, lxxxi (1935), 336–7.

Ibid. , 337; citations from Astrophysical journal are by permission of the publisher, Chicago University Press.

Ibid.

See, for example, Lindblad B. , “On the Spiral Orbits in the Equatorial Plane of a Spheroidal Disk with Applications to Some Typical Spiral Nebulae”, Upsala Astromiska Observatorium Meddelanden, No. 31 (1927). Since van Maanen never directly mentioned Lindblad, it is impossible to assess the effect of this theoretical work on him; however, van Maanen probably was aware of it. Also, Lundmark mentioned Lindblad's theory several times in his 1927 paper (ref. 121), which may make his failure to press home the attack against van Maanen more understandable as the theory supported van Maanen's direction for the rotations.

For a detailed study of absorption, see Seeley D. and Berendzen R. , “The Development of Research in Interstellar Absorption, c. 1900–1930”, Journal for the history of astronomy, iii (1972), 52–64, 75–86.

Letter, Hubble E. P. to Slipher V. M. , 11 June 1941 (Oort Papers, Leiden Observatory Archives). This letter was brought to our attention by D. Seeley.

Fernie , op. cit. (ref. 4), 1219.

Baade W. , Evolution of stars and galaxies (Cambridge, Mass., 1963), 28–29.

Hetherington N. S. , “Adriaan van Maanen and Internal Motions in Spiral Nebulae: A Historical Review”, Quarterly journal of the Royal Astronomical Society, xiii (1972), 25–39.

Op. cit. (ref. 38), 56–57.

For example, op. cit. (ref. 154).

Hart R. at Boston University.

It is interesting to speculate why the discovery was not made sooner. By 1913, Cepheids had been identified in the Magellanic clouds and by 1918 the period-luminosity relation (with which distances to Cepheids could be determined) was available. Thus, after 1918, someone might reasonably have attempted to find a Cepheid in a spiral. Certainly capable, interested observers were present, as Fernie has noted (op. cit. (ref. 4), 1226): Shapley himself, so adept at finding variable stars in globular clusters, had been in an excellent position for investigating their possible existence in spiral nebulae, but apparently so convinced was he that the nebulae were altogether something else, that he never did so. (Shapley has maintained (op. cit. (ref. 38), 57–58), however, that he did not do so because it was not his assigned task at Mt Wilson.) Even when variable stars were found in M33 (prior to Hubble's discovery), apparently no one suggested that they might be Cepheids ( Duncan J. C. , “Three Variable Stars and a Suspected Nova in the Spiral Nebula M33 Trianguli”, Publications of the Astronomical Society of the Pacific, xxxiv (1922), 290–1; Wolf M. , “Zwei Neue Veranderliche, Trianguli, im Spiralnebel M33”, Astronomische Nachrichten, ccxvii (1923), 475). And when Hubble made the definitive discovery in 1923, he at first thought he had found a nova instead of a variable, as is clear from his notebook entries and plate markings (see Mayall N. U. , “Edwin Hubble: Observational Cosmologist”, Sky and telescope, xiii (1954), 78–85). Thus, the discovery was accidental, not the result of a search. It is interesting to note that apparently no one proposed searching for Cepheids as a diagnostic of the island universe theory and, indirectly, the period-luminosity relation. There are several possible reasons for this: Shapley's P-L relation was not universally believed; in the entire world, only a handful of observers and telescopes were involved in studies of spirals; and hindsight may make the problem appear more obvious today than it was then. But it is possible that van Maanen's results, which seemed so lethal to the theory, may have dissuaded some astronomers from considering such an idea.