History and Education of the Albert A. Michelson Exhibition Developed at the Occasion of the Einstein Centenary Berlin 1979 and the Michelson Colloquium Potsdam 1981* ()
1. Einstein Centenary 1979 and Michelson Colloquium 1981
In his famous experiment in 1881 (Consoli & Pluchino, 2019) in the eastern basement of the Astrophysical Observatory Potsdam (Figure 1), Michelson intended to demonstrate that his interferometer (Lucas, 2023) was able to satisfy the task to verify the effect of the motion of the Earth on the propagation of light. It was expected that the velocity of light is composed of that of the Earth. The speed of the light should exceed the speed of the light which traverses the orbit by 30 km/s. In that case, the distance of the two images would depend on the orientation of the interferometer. The interferometer did not find any difference in the two velocities. Michelson had to conclude a so-called “null result” that the propagation of light was determined by the walls, just as the propagation of sound in the air of the basement room had to relate to the walls. Michelson’s interferometer result is a paradigmatic example of a null result in physics, a result may be said to be null when it not detected by the measuring device employed. The value returned by the measuring instrumentation is “zero”. It is very rarely the case that an unadulterated zero result will occur since there will almost always be measurable, small interfering causes and resultant noise at play. Thus, a better description of a null result is that it is “zero” plus small though annoying residual variations. Today, Michelson’s original experiment and its many repetitions are considered as a venerable well understood historical chapter for which, at least from a physical point of view, there is nothing more to refine or clarify. Though, this is not necessarily true, and this was also the subject of the Michelson Colloquium, and it remains the subject until today.
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Figure 1. Main building of the Astrophysical Observatory Potsdam, Telegrafenberg.
2. Astrophysical Observatory Potsdam 1881
From April 27 to April 30, 1981, an international colloquium in honour of the physicist and first American Nobel laureate Albert Abraham Michelson (1852-1931) and his scientific work took place in Potsdam, Germany. The occasion for this Michelson Colloquium at the Astrophysical Observatory Potsdam was the centenary of the year in which the famous Michelson experiment was performed for the first time in the Astrophysical Observatory Potsdam (Haubold & John, 1981, 1982; Goldberg & Stuewer, 1988).
The Michelson Colloquium was held under the auspices of the Academy of Sciences of the GDR (Central Institute for Astrophysics); its arrangement at the Astrophysical Observatory Potsdam was sponsored by the Einstein Laboratory for Theoretical Physics, Caputh, the Physical Society of the GDR, Berlin, and the Department of Physics of the Humboldt University, Berlin.
About one hundred years ago, in April 1881, Michelson performed for the first time his interferometer experiment to determine the velocity of the Earth relative to the hypothetical luminiferous aether—an experiment which entered history of physics and astronomy (Holton, 1988). The null result of the experiment, rejecting the aether hypothesis of Fresnel, turned out to be fundamental for the evolution of physics, as a landmark on the way of the genesis of Einstein’s theory of relativity. The incitement for undertaking such a crucial experiment Michelson had found in ideas of J.C. Maxwell. The interferometer by which he carried out his experiment and which he later used in various investigations in physics and astronomy, Michelson invented during a visit to Europe, beginning at the end of 1880 (Figures 2-6).
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Figure 2. Panels in the Rotunda of the main building of the Astrophysical Observatory Potsdam showing historical astronomical instruments used in the observatory after its foundation in 1874.
Figure 3. U. Bleyer and HJH in conversation with Konrad Wachsmann (USA; 1901-1980) during his visit of the 1979 Michelson exhibition in the main building of the Astrophysical Observatory Potsdam. He developed an industrial prefabricated wood construction system for single family houses in 1925 whose most famous product is the summer house of Albert Einstein (1879-1955) in Caputh/Potsdam.
Figure 4. Panels in the Michelson basement in the east dome of the Astrophysical Observatory Potsdam illustrating Michelson’s travel in visiting scientific institutions in Europe around 1881.
Figure 5. HJH welcoming Ilya Frank during the 1979 Einstein Centenary celebrations for his visit of the 1979 Michelson exhibition in the main building of the Astrophysical Observatory Potsdam. Ilya Mikhailovich Frank (Russia; 1908-1990) was a Soviet physicist who received the 1958 Nobel Prize for Physics, jointly with P.A. Cherenkov and I.Y. Tamm. He received the award for his work in explaining the phenomenon of Cherenkov radiation which, like Michelson’s interferometer, plays an continuing important role in experiments in natural sciences (today including the solar neutrino experiments with Kamiokande, SuperKamiokande in Japan, and Sudbury Neutrino Experiment in Canada).
The device was made by the optical firm Schmidt and Haensch in Berlin (Kuchejda, 2014) and the experiment was prepared at the Physical Institute of the Friedrich Wilhelms University of Berlin (later Humboldt University), located at the Reichstagsufer and lead by Hermann von Helmholtz (Jaffe, 1960; Cahan, 2004). However, because of the sensitivity of the instrument against vibrations, one had to look for a place of lower vibration level. The memorable experiment was finally realised in the Astrophysical Observatory Potsdam, not far from Berlin. As Michelson later mentioned, the then director of the Observatory, H.C. Vogel, was at once interested in the experiment. The whole experimental set up was placed in the basement of the east dome of the main building of the Observatory (Figure 6).
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Figure 6. Reconstruction of the original Michelson interferometer located in the Michelson basement. Today the use of this Michelson interferometer is demonstrated by Dierk-Ekkehard Liebscher (center of the photo) to visitors of the Astrophysical Observatory Potsdam.
2.1. WEMPE: Topic History Michelson Experiment Berlin
For nearly two years Michelson roamed the universities of Germany and France. He absorbed all the knowledge he could from the great men of European physics. He attended the lectures of Hermann von Helmholtz, the world-famous professor of theoretical physics at the University of Berlin, and did some laboratory work there. He drew plans for his interferometer and turned them over to the instrument company Schmidt + Haensch in Berlin for construction. Michelson made his first trial at the laboratory of Hermann von Helmholtz, at the University of Berlin (Wempe, 1906-1980; Wempe, 1975). They had discussed the experiment at length. Helmholtz stressed the difficulties of keeping a constant temperature. Further, even though the interferometer was set on a solid-stone pier in Helmholtz’s laboratory, vibrations from the Berlin traffic disturbed the observations, at night as well as in the daytime (Reingold, 1966). In April, Michelson had the apparatus dismantled and taken to the Astrophysical Observatory Potsdam for another trial. There, in a hollow space in the brick pier below an astronomical telescope, Michelsons acutely sensitive instrument finally appeared to give a clear result. To his amazement, the experiment produced a zero effect. Michelson could find no drag on the transmission of light in any direction. He detected only the slightest shift in the interference fringes. Both halves of the split single beam of light were returning at virtually the same instant. He recorded his findings in the August 1881 (5) issue of the American Journal of Physics under the title “The Relative Motion of the Earth and the Luminiferous Ether”. His conclusion was short and unmistakable “The hypothesis of a stationary ether is erroneous” he wrote.
2.2. LIEBSCHER: Topic Education Michelson Experiment
For educational purposes, D.-E. Liebscher (Liebscher, 2023) discussed the Michelson experiment and its family of misunderstandings. There are only a few experiments in physics which are cited by name in textbooks of general education. The Michelson experiment is the most known because it is rated to be the foundation of the theory of relativity. In general, it is known that Michelson intended to measure the headwind in the ether which is felt by the Earth on its orbit around the Sun. One knows that the theory of relativity is referring to it because the expected headwind was not found. Again, in general, one will not have been informed why one needs an ether at all, why the headwind was expected in a basement, and why this all has to do with relativity. Why did one need a luminiferous aether at all? With superposition of velocities through addition, for observers in relative motion, at most one observes the propagation of a wave as isotropic (independent of its direction). An observer can calculate velocity by evaluation of the anisotropy he observes. Galilei argued that any velocity is relative to some object, but where is the object here? It is an (the) aether. In this aether one expects the light to propagate isotropic. For the moment, Galileo’s postulate of relativity is saved by the aether.
Is the existence of an aether equivalent to an absolute space or absolute rest? This is a matter of wording. The notion of absolute space is at first pure invention. In order to identify position, orientation, time, and velocity one has to refer to other material objects, not to any virtual space. This is the summary of Galileo, and the reason for Newton’s second law. When one understands absoluteness with respect to rotation, space is absolute in Newton’s mechanics and in Einstein’s relativity as well. One may identify the aether with absolute space, or one may see in the aether an object in space, an object with no place, no time, no orientation, but serving as reference for velocities. But there is no impact on dynamics at all. Objects with these properties are the cosmic background of the different neutrinos, WIMPS, photons. With respect to the photon background, the Earth moves with about 500 km/s. Therefore, a Michelson-type expectation would be prominent in the Michelson experiment.
The thirteen lectures delivered at the Michelson Colloquium (Treder, 1982), with large thematic variety gathering round the Michelson experiment as the focus, especially appreciated its importance for physics and astronomy and dealt with philosophical and scientific historical aspects of the Michelson experiment. They took place during two days in a solemnly decorated room of the old city-hall of Babelsberg.
3. Friedrich Wilhelm University Berlin 1881
On April 28, Hans-Juergen Treder (1928-2006) (Astrophysical Observatory Potsdam, Potsdam, Germany) opened the jubilee colloquium and Michelson exhibition by welcoming special guests and participants to the internationally organized colloquium which was understood as a natural follow-up to the Einstein Centenary celebrations (Figure 3 and Figure 5) held in Berlin and Potsdam in 1979.
J. Auth (1930-2011; Humboldt University, Berlin, Germany) delivered the opening lecture “Albert A. Michelson at the University of Berlin”. By means of documents from the archive of the Humboldt University, Auth portrayed Michelson’s scientific visit to Berlin and the preparation of the experiment. In that he built upon a detailed investigation of H.J. Haubold and R.W. John “Albert A. Michelson’s aether drift experiment 1880/1881 in Berlin and Potsdam” (Treder, 1982; Haubold & John, 1981, 1982). Auth also sketched the social life of that time at the University of Berlin. In detail he devoted his attention to the theory and the physical consequences of the Michelson experiment.
4. Dorothy Michelson Livingston: Biograph of Albert A. Michelson
Dorothy Michelson Livingston (1906-1994; New York, USA) delivered the keynote address titled “Michelson and Einstein, artists in science”. Mrs. Michelson Livingston (Figures 7-11) drew a vivid picture of her famous father and analysed the characteristics of his creative activity, especially in comparison with Albert Einstein. From her memories she made the audience familiar with the great experimental physicist Albert A. Michelson, who was painting with pleasure in his spare time and was athletically active up to the old age. At that the lecturer showed slides from her private photo collection. Mrs. Michelson Livingston is the author of the outstanding Michelson biography “The Master of Light”, first published in 1973 (Treder, 1982; Michelson Livingston, 1973; Ryan, 1987; Millikan, 1938; The Albert A. Michelson Nobel Prize and Lecture, 1966). She finished her lecture with words spoken by Einstein in appreciating Michelson when meeting him at the California Institute of Technology, Pasadena, in January 1931, a few months before the death of Michelson: “It was you who led the physicists into new paths, and through your marvellous experimental work paved the way for the development of the theory of relativity” (see also Appendix).
4.1. Topic Einstein and Michelson (Hoffmann & Dukas, 1973; Haubold & Yasui, 1986)
“I always think of Michelson as the artist in science. His greatest joy seemed to come from the beauty of the experiment itself, and the elegance of the method employed. But he has also shown an extraordinary understanding for the baffling fundamental questions of physics. This is evident from the keen interest he has shown from the beginning for the problem of the dependence of light on motion.”
—Albert Einstein (Livingston, Dorothy Michelson. The Master of Light: A Biography of Albert A. Michelson (Michelson Livingston, 1973)
Figure 7. Cover of the original edition of the Michelson biography published in 1973 by Dorothy Michelson Livingston. This biography describes in detail Michelson’s scientific work against the background of family life. Her book, which she has described as “a quest for my father”, is the result the life-long research that let her travel through the world, particularly through all of European countries where her father pursued scientific studies. https://digital.case.edu/islandora/object/ksl:2006061209
Figure 8. Dorothy Michelson Livingston opening speech of the Michelson Colloquium.
Figure 9. Letter from Helen Dukas to Dorothy Michelson Livingston constituting the quest of her research on the relation between Einstein and Michelson and the role that Michelson’s interferometer experiments played in Einstein’s discovery of special relativity (Michelson Livingston, (1906-1994)a).
Figure 10. Letter from Max Born to Dorothy Michelson Livingston summarizing Max Born’s view of the Michelson experiment for the benefit of Einstein’s research work in relativity (Michelson Livingston, (1906-1994)b).
Figure 11. Watercolour painted by Albert A. Michelson, Altadena, California, 1929. Figure provided by the Special Collections & Archives Division, Nimitz Library, United States Naval Academy, www.usna.edu/LibExhibits/Michelson/Michelson_personal.html, Click on “Michelson Painting” for a video showing a Michelson painting accompanied b music composed by Michelson.
4.2. Topic Born and Michelson (Born, 2005)
The Michelson experiments were made by the American physicist Miller, first in flat country and later on top of Mount Wilson, a high mountain. To begin with, he claimed to have discovered, using his Michelson interferometer, the so-called aether wind. Sometime later he withdrew the claim; the shift of the interference fringes, on which he had based his claim, had been too small. I believe he then attributed it to the movement of the solar system. When I was in the United States in 1925/26, Miller’s measurements were still frequently being discussed. I therefore went to Pasadena to see a demonstration of the apparatus on top of Mt. Wilson. Miller was a modest little man who very readily allowed me to operate the enormous interferometer. I found it very shaky and unreliable; a tiny movement of one’s hand or a slight cough made the interference fringes so unstable that no readings were possible.
From then on I completely lost faith in Miller’s results. I knew from my visit to Chicago in 1912 that Michelson’s own apparatus was very reliable and his measurements accurate. My scepticism has been substantiated by later developments. Michelson’s result that the aether wind does not in fact exist is universally accepted today.”
4.3. ROOT-BERNSTEIN: Topic Artist Michelson
Albert Michelson had many interests outside of the realm of physics and science, including music, art, billiards, chess, and tennis. His interest in the violin began when he was a child, grew during his years at the Naval Academy, and eventually led to musical composition. Michelson expressed his interest in art through sketching and painting watercolors. The majority of Michelson’s paintings were completed in his later years and during his retirement, consisting mostly of watercolors of California landscapes. Some of Michelson’s watercolors were exhibited at the Pasadena Art Institute in 1931, shortly before his death (Root-Bernstein, 2006).
Michelson was also an artist. In 1928, he had a one-man exhibition at the Renaissance Society of the University of Chicago and exhibited two watercolours (Antofagasta, Chile and Vigo Harbor, Spain) at the Art Institute of Chicago’s Eighth Annual Exhibition of Watercolours by American Artists. At one of these exhibits, “one woman told Michelson he should never have given up art for science. ‘I did not have to choose,’ he answered, ‘because for me they are inseparable’”. Indeed, 25 years previously, in his book Light Waves and Their Uses (1903), Michelson had written:
And painting lessons each Sunday from Rudolph Weisenborn at the Chicago Academy of Fine Arts and amused himself by drawing caricatures of acquaintances. After he remarried, he built a house in Chicago in 1923 with a conservatory in which his wife grew flowers and both sat and drew or painted, a habit they took outdoors in their later years in Pasadena, California.
As a supplement communication during the Michelson Colloquium, Mrs. Dorothy Michelson Livingston made a lively presentation with photography and paintings on her father as an artist in science and technology.
5. Case Western Reserve University 1887: Michelson-Morley Experiment
R. S. Shankland (1908-1982) (Case Western Reserve University, Cleveland, Ohio, USA) on “Michelson in Potsdam” did summarize the results of the experiments in Potsdam and in Cleveland in 1887, when Michelson in cooperation with E.W. Morley repeated the aether-drift experiment with higher precision. The result confirmed the null result of the Potsdam experiment. Shankland himself was leading engaged in the disclosure of the misinterpretation of the result announced by D.C. Miller in single carrying out a further repetition of the Michelson experiment. Shankland lucidly and concisely presented that part of Michelson’s scientific activity, which begins with his collaboration with S. Newcomb, then, in 1880, lead to the visit to Europe—stations were Paris and Berlin/Potsdam—and which included the invention of the Michelson interferometer, its construction in Berlin, the preparation of the experiment in Hermann von Helmholtz’ institute, and finally, the realization of the experiment in the Astrophysical Observatory Potsdam. At that time, H. von Helmholtz was already a famous scientist, inter alia for his contributions to physical optics and the foundation of physiological optics. His laboratory was a renown modern centre for optical research. This intensive scientific environment no doubt was an important factor in Michelson’s progress, as Shankland stated (Treder, 1979; Shankland, 1953, 1954).
H. Melcher (1927-2022; Training College for Teachers, Erfurt, Germany) contributed a brief annotation concerning some special questions of the history of the aether-drift experiment and the genesis of special relativity (Treder, 1982; Renn et al., 2003).
R. Rompe (1905-1993; Physical Society, Berlin, Germany) and G. Albrecht (1930-2015; German Academy of Sciences, Berlin, Germany) focused in a joint presentation on a more general topic “The importance of experiments for the progress in physics”. Rompe pointed out, how “the nearness of an experiment to experience”, what was just existing yet in Michelson’s investigations, today threatens to fade away due to the more and more increasing complexity of the experimental proceeding in physics and the necessary inclusion of electronic data processing. He stressed the tight nexus of physical conception, mathematical theory, and experiment. So, on one hand, the experimental advance is essential for the development of physical theory, but, on the other hand, according to a remark made by Einstein to Heisenberg, designing an experiment is again decisively co-determined by the theory. The lecturers spoke about the methodical benefit one may also yet today derive from Albert A. Michelson’s, the great master of precision optics, style of working (Treder, 1982).
K. Lanius (1927-2010; Institute of High Energy Physics, Zeuthen, Germany) was dealing with the statistical evaluation of experiments in an additional part of the previous lecture (Treder, 1982).
H.-G. Schoepf (1928-2004; University for Science and Technology, Dresden, Germany) delivered on overview on the status of physics in the 19th century in his lecture “Maxwell’s aether theories”. In an enthusiastic and exciting manner, he coherently displayed the ways which have led Maxwell via different mechanical aether models to his famous equations of electromagnetism (Treder, 1982; Schöpf, 1978).
6. Michelson-Morley-Miller Experiments and Einstein’s Relativity Theory
L. S. Swenson Jr. (1932-2016) (University of Houston, Texas, USA), the widely known historian of science, discussed in detail “The Michelson-Morley-Miller experiments and the Einsteinian synthesis”. Swenson (Figure 12) described the history of these experiments in connection with the rise of the special theory of relativity (Treder, 1982; Swenson Jr., 1972). In that he stressed that the history of physics must be seen in connection with the history of technology. At the end of his lecture Swenson raised several questions concerning the history of the theory of relativity. He also highlighted that in the Munich Deutsches Museum letters from the Einstein-von Laue correspondence is deposited which should be published in the future.
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Figure 12. From left U. Ulmer (youngest daughter of D. Michelson Livingston), D. Michelson Livingston, R.W. John (1942-2007; co-organizer of the Michelson Colloquium), L.S. Swenson, during the deliberations of the Michelson colloquium in Potsdam 1981. https://researchfeatures.com/dorothy-michelson-livingston-personal-recollection/
SWENSON: Research Topic Michelson Experiment
In summary here, let me suggest a series of five primary problems and unanswered questions which seem to me to be middle range historical needs for further research (Treder, 1982):
1) Has anyone done a comparative experimental biography of the pioneer terrestrial measurers of the velocity of light, focussing on the French school, especially Foucault and Fizeau in I850? This seems a big and dramatic problem.
2) Do we have adequate monographic accounts of the works of Michelson’s mentors, particularly of Jamin,
Mascart, Cornu, Quincke, and Vogel? What is the best historical work on Hertz?
3) Has Walter Ritz’s attempted revival of the emission theory of light around 1907 been adequately studied? Have the specific contributions and influence of Georg Joos at Jena with Zeiss interferometers of 1930 been re-examined?
4) Since the work of Shankland and his group in I955, has any astrophysicist or celestial mechanician re-examined the significance of Dayton Miller’s “secret history” and review paper of 1935 “The Ether-Drift Experiment and the Determination of the Absolute Motion of the Earth”, Reviews of Modern Physics 5: 203-234, July 1933? Gustav Stroemberg at Mount Wilson before his death suggested some oversights here.
5) Is there any adequate treatment of Max von Laue and his relations with Einstein? There are 44 letters in the Münchener Deutsches Museum that should be suitably published, von Laue was one of Einstein’s first and last friends, a peer!
7. Aether Models
J.P. Vigier’s (1920-2004; Institute Henri Poincare, Paris, France) lecture opened the modern view of “Einstein’s and Dirac’s aether models”. After having stated the classical aether models are killed by the null result of the Michelson experiment, Vigier (Figure 13) investigated the justification of stochastic covariant aether models. He dealt with the relativistic generalization of results obtained by Einstein and Marian von Smoluchovsky on Brownian motion. Discussing the relation of superluminal velocities and causality he rested upon experiments performed by A. Aspect (Treder, 1982; Vigier, 1997).
Figure 13. From the left V. Vigier, Z. Maric, and E. Kreisel (b. 1937). In the background examples are visible of the 12 large exhibition panels (Figure 2 and Figure 4) produced for the Einstein Centenary 1979 in Potsdam and Berlin and the Michelson Colloquium 1981 in Potsdam.
8. Quantum Mechanical Measuring
F.W. Kaschluhn’s (1927-1994; Institute of Theoretical Physics, Humboldt University, Berlin, Germany) “Interference and correlation phenomena in quantum theory” perspicuously worked out a problem connected with the microphysical description of single systems, the overcoming of which obviously demands additional assumptions about the quantum mechanical measuring process (Treder, 1982).
Z. Maric (1931-2006; Institute of Physics, Belgrade, Yugoslavia) posed his lecture, likewise dealing with quantum field theory, under the theme: “Vacua and symmetries”. Maric (Figure 13) investigated the vacuum concept on different stages of development of physics, especially he emphasized the relation of this concept to the internal geometry of space (Treder, 1982).
J. Stachel (b.1928; Department of Physics, Princeton University, Princeton, USA) focused in his lecture titled “Einstein and Michelson: The Context of discovery and the context of justification” on the fact that a philosopher of science is not interested in the context of discovery, but in the context of justification and that it appears amazing to what extent the logical analysis of relativity coincides with the original interpretation by its author, as far as it can be constructed from the scanty remarks in Einstein’s publications. According to Stachel (Figure 14), in contradistinction to some developments in quantum theory, the logical schema of the theory of relativity corresponds surprisingly with the program which controlled its discovery. This agrees with the independent analysis of philosophers and scientists as Hans Reichenbach and Gerald Holton (Treder, 1982; Stachel, 2002; Holton, 1988).
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Figure 14. H.-J. Treder and J. Stachel in front of the fireplace in Einstein’s Summer House in Caputh.
H.-J. Treder (1928-2006) (Observatory Babelsberg, Potsdam, Germany) celebrated in the concluding speech of the colloquium “The Michelson experiment as experimentum crucis”. Dealing with this theme, and simultaneously aspiring a synopsis of the most important statements involved in the foregoing lectures, Treder (Figure 14) stressed the following central aspects: The art and importance to perform experiments, the creation of new experiments from putting of important physical questions; the question of the existence or non-existence of the aether; the meaning of classical questionings, from Michelson to Einstein and from Einstein to Bohr, at the present time (Treder, 1982).
TREDER: Topic History Michelson Experiment Potsdam
There are several problems and unanswered questions which seem to me to be middle range historical needs for further research:
The Einstein effect that needs a better historical comprehension of the expedition of Freundlich.
Schwarzschild was an important representative relativity theory: Why did Einstein focus on Freundlich and not focus on Schwarzschild in the case of experimental verification of the curvature of space.
In the period of time from 1922 to 1932 there existed a curatorium for the Astrophysical Observatory Potsdam (von Laue, Einstein, Nernst, Mueller, Gehrke, Paschen, Schrödinger). What did this curatorium pursue? (Treder, 1928-2006).
The organizers of the Michelson Colloquium took advantage of this event in planning visiting opportunities between lecture sessions and beyond. All participants of the colloquium were invited to visit the main building of the Astrophysical Observatory Potsdam (Figure 1), the Einstein Tower on the Telegrafenberg (Figure 15), and the Einstein House in Caputh near Potsdam (Figure 16). Many of the colloquium lectures did touch historical, scientific, and social issues which are part of research programmes as analysed in depth, for example, in Holton’s scientific papers. Long time after the discoveries addressed by lectures of the Michelson Colloquium the decision was made to rename the main building of the Astrophysical Observatory to be the Michelson building to honour Michelson’s first experiment.
Figure 15. Einstein Tower, Telegrafenberg, Potsdam.
Several participants had the unique opportunity to be accommodated as guests in the summer house of Einstein in Caputh and were invited to continue the colloquium deliberations in guided tours and discussion sessions (Figure 16 and Figure 17). The summer house built for Albert Einstein in Caputh close to Potsdam in 1929 by the young architect Konrad Wachsmann is of great cultural and architectural importance. The house is the result of close interaction between the requests of Albert Einstein and the ideas of Konrad Wachsmann. The ample window front of the spacy living room with its open lightness goes back to the ideas of the architect and invited even at Einstein’s time to meeting sessions. Unfortunately, constant change of use and ownership as well as lack of financial resources and material resulted in a lack of maintenance work. Over long time, legal debate about the ownership of the house prevented necessary restoration. Yet through all ups and downs of its history the house has preserved a high degree of authenticity and has always remained the “summer house of Albert Einstein”. During the Michelson Colloquium the house was elevated to be the host of the Einstein Laboratory for Theoretical Physics lead by H.-J. Treder.
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Figure 16. Einstein’s Summer House in Caputh.
Figure 17. From the left U. Ulmer, F.W. Jaeger (1914-2000; former director of the Einstein Tower, Telegrafenberg, Potsdam), D. Michelson Livingston in the Einstein House Caputh, in the background the Einstein bust created by Heinrich Drake in 1981.
A unique element of the programme of the Michelson Colloquium for all participants was the opportunity to visit the Einstein Tower through guided tours and discussion sessions. The Einstein Tower is an astrophysical observatory on the Telegrafenberg later to become the Albert Einstein Science Park in Potsdam, Germany, built by architect Erich Mendelsohn. It was built on the summit of the Potsdam Telegrafenberg to house a solar telescope designed by the astronomer Erwin Finlay-Freundlich. The telescope supports experiments and observations to validate (or disprove) Albert Einstein’s relativity theory. The building was first conceived around 1917, built from 1919 to 1921, and became operational in 1924. Although Einstein never worked there, he supported the construction and operation of the telescope. Light from the telescope is directed down through the shaft to the basement where the instruments and laboratory are located. In 1911 Einstein published the initial version of his General Theory of Relativity. One of the predicted effects according to the theory was a slight shift of spectral lines in the sun’s gravitation field, now known as the red shift. The solar observatory in Potsdam was designed and constructed primarily to verify this phenomenon.
100 years were gone since the Michelson experiment was performed for the first time in Potsdam—this also meant 50 years since Albert A. Michelson’s death—but, as the lectures of the Michelson Colloquium showed, the physical and scientific historical discussion continuously inflames at this decisive experiment which signalized a revolution in the development of physics. Also, in dealing with questions in more distant fields, the discussions looked back at this experiment as a pioneering event in the history of physics (Bussemer & Mueller, 2022; van Dongen, 2009).
Acknowledgements
Professor Dr. Johann Wempe (1906-1980), former director of the Astrophysical Observatory Potsdam. He was the editor of the Astronomische Nachrichten journal for 22 years and, after his retirement, became interested in the history of astronomy in Potsdam. In 1975 it was him who announced publicly that Alber A. Michelson performed his famous experiment in the AOP in 1881. Dring the visit of Dorothy Michelson Livingston on her trip through Europe for the benefit of her writing the biography of father, Wempe joint her in Berlin and Potsdam to explore what today is known about the Michelson cellar at the AOP (personal communication in 1975).
Members of the Working Group on Formation of Structure in the Universe (Jan-Peter Muecket, HJH, Volker Mueller, and Stefan Gottloeber), contributing to the Michelson Exhibition 1979 and 1981 at the Astrophysical Observatory Pots-dam and Astronomical Observatory Babelsberg.
All lectures given, and discussions pursued during the Michelson Colloquium have been recorded and are made available on request (courtesy of Klaus Fritze, Observatory Babelsberg, Potsdam, Germany).
Text and photos of all 12 panels (in German language) of the Michelson exhibition for 1979 Einstein Centenary and 1981 Michelson Colloquium are available on request (courtesy of Horst Strohbusch, Astrophysical Observatory Potsdam, Telegrafenberg, Potsdam, Germany).
The author undoubtedly failed to include publications by other authors that have equally good connections with, or illuminating commentary on, the issues told in this article. The author shall be grateful to those who write to him to point out such deficiencies.
Personal Communication of the Author with Respective Scientists
Liebscher, D. E. (2023). Former Director of the Astronomical Observatory Babelsberg, Personal Communication with HJH.https://www.dierck-e-liebscher.de/lectures/michelsonAll-e.html
Michelson Livingston, D. ((1906-1994)a). courtesy of, youngest daughter of Albert A. Michelson, Letter from Helen Dukas, former life-long secretary of Albert Einstein to Dorothy Michelson Livingston dated 24 May 1971, Fig 9. personal communication with HJH in Wainscott (July 1989).
Michelson Livingston, D. ((1906-1994)b). courtesy of, youngest daughter of Albert A. Michelson, Letter from Max Born, close friend of Albert Einstein, to Dorothy Michelson Livingston, dated 5 June 1964, Fig 10. personal communication with HJH in Wainscott (July 1989).
Swenson Jr., L. S. (1932-2016). Professor Emeritus, University of Houston, History Department, Personal Communication (during the Deliberations of the Michelson Colloquium in Potsdam 1981).
Treder, H.-J. (1928-2006). former Director of the Astrophysical Observatory Potsdam, Telegrafenberg, and the Astronomical Observatory Potsdam, Babelsberg, personal communication (21 January 1977, and 21 August 1995).
Wempe, J. (1906-1980). former Director of the Astrophysical Observatory Potsdam, personal communication with HJH (1 March 1979), discovering that the first trial of Michelson with his interferometer, build by Schmidt + Haensch Berlin, was not set up in the Magnus-Haus in Berlin, but in the Physical Laboratory of Hermann von Helmholtz.
Appendix
Keynote Address of Dorothy Michelson Livingston Prepared for the Einstein Centenary Berlin 1979 and the Michelson Colloquium Potsdam 1981.
NOTES
*The paper is dedicated to the 200th Anniversary of the oldest astronomical journal, Astronomische Nachrichten, founded by H. C. Schumacher in 1821 and the150th Anniversary of the establishment of the Astrophysikalisches Observatorium Potsdam (AOP) on 1st July 1874.