ResearchOnline@JCU This file is part of the following reference: Montgomery, Colin Robert Lister (2014) From Michell to MACHO: changing chronological perspectives on the concept of 'Dark Matter' in astronomy and astrophysics. MPhil thesis, James Cook University. Access to this file is available from: http://researchonline.jcu.edu.au/41364/ The author has certified to JCU that they have made a reasonable effort to gain permission and acknowledge the owner of any third party copyright material included in this document. If you believe that this is not the case, please contact [email protected] and quote http://researchonline.jcu.edu.au/41364/ DARK MATTER from MICHELL to MACHOS From Michell to MACHO: Changing Chronological Perspectives on the Concept of ‘Dark Matter’ in Astronomy and Astrophysics Thesis submitted by Colin Robert Lister MONTGOMERY, ASTC (UT, Syd.), Master of Astronomy (UWS) October, 2014 for the degree of Master of Philosophy (Natural and Physical Sciences) in the School of Engineering and Physical Sciences, James Cook University 1 DARK MATTER from MICHELL to MACHOS STATEMENT OF ACCESS I, the undersigned, author of this work, understand that James Cook University will make this thesis available for use within the University Library and, via the Australian Digital Thesis network, for use elsewhere. I understand that, as an unpublished work, a thesis has significant protection under the Copyright Act and; I do not wish to place any further restriction on access to this work. Colin R L Montgomery 20. 10. 14 Date Signature 2 DARK MATTER from MICHELL to MACHOS STATEMENT OF SOURCES DECLARATION I declare that this thesis is my own work and has not been submitted in any form for another degree or diploma at any university of tertiary education. Information derived from the published or unpublished work of others has been acknowledged in the text and a list of references is given. Colin R. L. Montgomery 20. 10. 2014 Date Signature 3 DARK MATTER from MICHELL to MACHOS STATEMENT OF CONTRIBUTION BY OTHERS I, the undersigned, author of this work, confirm that I have not received any financial help in the preparation of this thesis, but I did receive some editorial assistance from my supervisors. Colin R. L. Montgomery 20.10.14 Date 4 DARK MATTER from MICHELL to MACHOS ELECTRONIC COPY DECLARATION l, the undersigned, the author of this work, declare that the electronic copy of this thesis provided to the James Cook University Library is an accurate copy of the print thesis submitted, within the limits of the technology available. Colin R.L. Montgomery 20.10.2014 Date Signature 5 DARK MATTER from MICHELL to MACHOS ACKNOWLEDGEMENTS Very special thanks to my Supervisors: Associate Professor Wayne Orchiston and Professor Ian Whittingham of the School of Engineering and Physical Sciences at James Cook University. A special thanks to two librarians for their assistance in locating old and sometimes misplaced papers and documents: the late Sandra Ricketts, Librarian, Anglo-Australian Observatory, Epping, NSW, Australia; Joanna Corden, Archivist and Records Manager, The Royal Society, London, UK; and to the following other helpful librarians: Antoinette Beiger, Librarian, Lowell Observatory, Arizona, USA; Rita Bisley, Librarian, James Cook University, Townsville, Queensland. Australia; Liesbeth van Iterson, Librarian, Astronomical Institute ‘Anton Pannekoek’, University, Amsterdam, The Netherlands; Julie Kelly, Librarian, British Library, London, UK; Dorothea Trottenberg, Librarian, Basel University, Basel, Switzerland; and Diane Warden, Librarian, British Library, London, UK. I also wish to thank the following astronomers for their assistance: Dr Victor K. Abalakin, former Director of the Special Astrophysical Observatory, Pulkovo, St. Petersburg, Russia; Dr Stuart Ryder, Astronomer, Anglo-Australian Observatory, Epping, NSW, Australia; Dr Marat G. Mingaliev, Deputy Director, Special Astrophysical Observatory, Pulkovo, St. Petersburg, Russia and Dr Graeme White, former Director of the Centre for Astronomy at James Cook University. This Research has made extensive use of the NASA’s Astrophysics Data System ____________________________________________ 6 DARK MATTER from MICHELL to MACHOS ABSTRACT The underlying theme of this thesis is 'missing mass' which extends back to John Michell's (1767) paper on the parallax of fixed stars. He foresaw that our galaxy was part of a system in our own part of the Universe, independent of other systems which existed at great distances. This understanding of the independence of our galaxy was necessary before its mass could be calculated and the final recognition that there was 'missing mass'. In 1933 Fritz Zwicky published a paper in Helvetica Physica ACTA in which he introduced the concept of ‘dark matter’ to explain the ‘missing mass’ in the Andromeda Nebulae, specifically its Coma Nebulae. This launched a series of studies which culminated, during the 1990s, in a number of international teams (including two from Australia) using gravitational microlensing to search for evidence of 'dark matter' in our Galaxy. This thesis examines these 'dark matter' studies and demonstrates that the concept of ‘dark matter’—in one guise or another—extends back to John Michell and a seminal paper that he published in 1784. It also reveals that in the late nineteenth and early twentieth centuries, following the emergence of astrophysics, various astronomers foreshadowed Zwicky’s pioneering studies. The history examines the ways in which the changing concept of ‘dark matter’ has contributed to our understanding of astronomy and astrophysics between 1784 and the present day. John Michell was interested in the concepts of probability. After reviewing William Herschel’s paper on double stars he suggested that if there were luminous double stars there was a high probability that one of a pair of stars could be non-luminous. He then proceeded to calculate the size of a body from which light could not escape because of its force of gravity. This body eventually became known as a ‘black hole’. Michell also suggested that the proper motions of a luminous body could be disturbed by the nearby presence of a non-luminous body, known as perturbation. Fifty years later Fredrich Bessel verified Michell's concept of perturbation by gravity, by applying the corrected clock times of 1834 to the proper motions of Procyan and Sirius, which had been previously recorded in 1755. J.F.W. Herschel confirmed this fact and concluded “The existence of numberless visible stars can prove nothing against the existence of numberless invisible ones” (Herschel, 1845:141). Early in the 20th century Edward E. Barnard produced his catalogue of ‘dark patches in the sky’ and disagreed with other astronomers who suggested that some of the dark patches were formed by ‘opaque mass of some sort’. 7 DARK MATTER from MICHELL to MACHOS One of the biggest changes on our perspective of 'dark matter' was a result of the ‘Great Debate’ in 1920 between Harlow Shapley and Herber D. Curtis which led to the acceptance of Curtis’ view of the size of our galaxy confirming Michell's (1767) foresight. The acceptance of an independent galaxy was necessary before the amount of ‘missing mass’, which was holding the Galaxy together, could be calculated Jacobus C. Kapteyn took the first step with his paper in 1922 entitled “First Attempt at a theory of the Arrangement and motion of the Sidereal System” in which he estimated the number of luminous stars and their average mass and suggested that this only made up half of the mass of the Galaxy and the balance must be 'dark matter'. This work was further confirmed by Kayteyn's student Jan H. Oort (1926) paper "Non -light-Emitting matter in the Stellar System". This work was confirmed by Fitz Zwicky in important papers published between 1933 and 1942, mostly based on the rotational speed of the Coma Cluster. Zwicky arrived at a figure of 1000 km/sec, which was 400 hundred times that which was expected. No further research was done in related to 'dark matter' until 1970 when Kenneth Freeman renewed the interest in the mass of spiral galaxies, which eventually led to the discovery that there was 'missing mass'. His studies on their circular-velocity field and mass-angular momentum densities and their proportion of the total light for each of the spheroidal and exponential components became known as Freeman Law. Two short papers one by Einasto et al., (1974) and another by Ostriker et al., (1974) discussed the missing mass around galaxies and of the universe. They concluded that there existed non-observable mass within the galaxies and a large part of the mass was on the outer regions. These papers add a little more understanding of the proposals by Freeman (1970). After a few similar conceptual papers over the next decade by Margon (1975), Shields (1978) and Bailey (1982), Rubin et al., (1983) attempted to answer the question "Is the distribution of luminosity in galaxies a reliable distribution of mass? (Rubin. et al., 1983). They also applied the same question to the universe. This was a very detailed paper and did indicate the locations of mass in galaxies and concluded that there was an unknown fraction of mass in spiral galaxies and clusters hidden by a non-luminous constituent. Peebles (1984) attacked the question of 'dark matter' from a different perspective moving from the observation of the effect of 'dark matter' objects on nearby luminous matter to a theoretical analysis. He based his model on a set of interesting assumptions which he hoped would lead to a realistic model. However this model does not seem to have evolved. In 1987 the most cited paper on the subject of 'dark matter' was published by Albada and Sancisi (1987). They proposed that the amount of 'dark matter' can be calculated by 8 DARK MATTER from MICHELL to MACHOS comparing the observed rotation curves with the rotation curves based on the distribution of light.