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A conference in Paris

This week I’m in Paris, attending a conference in memory of the outstanding British astronomer and theoretician Arthur Stanley Eddington. The conference, which is taking place at the Observatoire de Paris, is designed to celebrate the centenary of Eddington’s famous measurement of the bending of distant starlight by the sun.  a key experiment that offered important early support for Einstein’s general theory of relativity. However, there are talks on lots of different topics, from Eddington’s philosophy of science to his work on the physics of stars, from his work in cosmology to his search for a unified field theory. The conference website and programme is here.

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The view from my hotel in Denfert-Rochereau

All of the sessions of the conference were excellent, but today was a particular treat with four outstanding talks on the 1919 expedition. In ‘Eddington, Dyson and the Eclipse of 1919’, Daniel Kennefick of the University of Arkansas gave a superb overview of his recent book on the subject. In ‘The 1919 May 29 Eclipse: On Accuracy and Precision’, David Valls-Gabaud of the Observatoire de Paris gave a forensic analysis of Eddington’s calculations. In ‘The 1919 Eclipse; Were the Results Robust?’ Gerry Gilmore of the University of Cambridge described how recent reconstructions of the expedition measurements gave confidence in the results; and in ‘Chasing Mare’s Nests ; Eddington and the Early Reception of General Relativity among Astronomers’, Jeffrey Crelinsten of the University of Toronto summarized the doubts expressed by major American astronomical groups in the early 1920s, as described in his excellent book.

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I won’t describe the other sessions, but just note a few things that made this conference the sort of meeting I like best. All speakers were allocated the same speaking time (30 mins including questions); most speakers were familiar with each other’s work; many speakers spoke on the same topic, giving different perspectives; there was plenty of time for further questions and comments at the end of each day. So a superb conference organised by Florian Laguens of the IPC and David Valls-Gabaud of the Observatoire de Paris.

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On the way to the conference

In my own case, I gave a talk on Eddington’s role in the discovery of the expanding universe. I have long been puzzled by the fact that Eddington, an outstanding astronomer and strong proponent of the general theory of relativity, paid no attention when his brilliant former student Georges Lemaître suggested that a universe of expanding universe could be derived from general relativity, a phenomenon that could account for the redshifts of the spiral nebulae, the biggest astronomical puzzle of the age. After considering some standard explanations (Lemaître’s status as an early-career researcher, the journal he chose to publish in and the language of the paper), I added two considerations of my own: (i) the theoretical analysis in Lemaître’s 1927 paper would have been very demanding for a 1927 reader and (ii) the astronomical data that Lemaître relied upon were quite preliminary (Lemaître’s calculation of a redshift/distance coefficient for the nebulae relied upon astronomical distances from Hubble that were established using the method of apparent magnitude, a method that was much less reliable than Hubble’s later observations using the method of Cepheid variables).

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Making my points at the Eddington Conference

It’s an interesting puzzle because it is thought that Lemaitre sent a copy of his paper to Eddington in 1927 – however I finished by admitting that there is a distinct possibility that Eddington simply didn’t take the time to read his former student’s paper. Sometimes the most boring explanation is the right one! The slides for my talk can be found here.

All in all, a superb conference.

 

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Filed under Astronomy, Cosmology (general), History and philosophy of science

The thrill of a good conference

One of the perks of academia is the thrill of presenting results, thoughts and ideas at international conferences. Although the best meetings often fall at the busiest moment in the teaching semester and the travel can be tiring, there is no doubt that interacting directly with one’s peers is a huge shot in the arm for any researcher – not to mention the opportunity to travel to interesting locations and experience different cultures.

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The view from my hotel in San Sebastian this morning.

This week, I travelled to San Sebastian in Spain to attend the Third International Conference on the History of Physics, the latest in a series of conferences that aim to foster dialogue between physicists with an interest in the history of their subject and professional historians of science. I think it’s fair to say the conference was a great success, with lots of interesting talks on a diverse range of topics. It didn’t hurt that the meeting took place in the Palacio Mirimar, a beautiful building in a fantastic location.

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The Palacio Mirimar in San Sebastian. 

The conference programme can be found here. I didn’t get to all the talks due to parallel timetabling, but three major highlights for me were ‘Structure or Agent? Max Planck and the Birth of Quantum Theory’ by Massimiliano Badino of the University of Verona, ‘The Principle of Plenitude as a Guiding Theme in Modern Physics’ by Helge Kragh of the University of Copenhagen, and ‘Rutherford’s Favourite Radiochemist: Bertram Borden’ by Edward Davis of the University of Cambridge.

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A slide from the paper ‘Max Planck and the Birth of Quantum Theory’

My own presentation was titled The Dawning of Cosmology – Internal vs External Histories’ (the slides are here). In it, I considered the story of the emergence of the ‘big bang’ theory of the universe from two different viewpoints, the professional physicist vs. the science historian. (The former approach is sometimes termed ‘internal history’ as scientists tend to tell the story of scientific discovery as an interplay of theory and experiment within the confines of science. The latter approach is termed  ‘external’ because the professional historian will consider external societal factors such the prestige of researchers and their institutions and the relevance of national or international contexts). Nowadays, it is generally accepted that both internal and external factors usually often a role in a given scientific advance, a  process that has been termed the co-production of scientific knowledge.

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Giving my paper in the conference room

As it was a short talk, I focused on three key stages in the development of the big bang model; the first (static) models of the cosmos that arose from relativity, the switch to expanding cosmologies in the 1930s, and finally the transition (much more gradual) to the idea of a universe that was once small, dense and hot. In preparing the paper, I found that the first stage was driven almost entirely by theoretical considerations (namely, Einstein’s wish to test his newly-minted general theory of relativity by applying it to the universe as a whole), with little evidence of co-production. Similarly, I found that the switch to expanding cosmologies was driven by almost entirely by developments in astronomy (namely, Hubble’s observations of the recession of the galaxies). Finally, I found the long rejection of Lemaître’s ‘fireworks’ universe was driven by obvious theoretical problems associated with the model (such as the problem of the singularity and the age paradox), while the eventual acceptance of the model was driven by major astronomical advances such as the discovery of the cosmic microwave background. Overall, my conclusion was that one could give a reasonably coherent account of the early development of modern cosmology in terms of the traditional narrative of an interplay of theory and experiment, with little evidence that social considerations played an important role in this particular story. As I once heard the noted historian Hasok Chang remark in a seminar, Sometimes science is the context’.

Can one draw any general conclusions from this little study? I think it would be interesting to investigate the matter further. One possibility is that social considerations become more important ‘as a field becomes a field’, i.e., as a new area of physics coalesces into its own distinct field, with specialized journals, postgraduate positions and undergraduate courses etc. Could it be that the traditional narrative works surprisingly well when considering the dawning of a field because the co-production effect is less pronounced then? Certainly, I have also found it hard to discern any major societal influence in the dawning of other theories such as special relativity or general relativity.

Coda

As a coda, I discussed a pet theme of mine; that the co-productive nature of scientific discovery presents a special problem for the science historian. After all, in order to weigh the relative impact of internal vs external considerations on a given scientific advance, one must presumably have a good understanding of each. But it takes many years of specialist training to attempt to place a scientific advance in its true scientific context, an impossible ask for a historian trained in the humanities. Some science historians avoid this problem by ‘black-boxing’ the science and focusing on social context alone. However, this means the internal scientific aspects of the story are either ignored or repeated from secondary sources, rather than offering new insights from perusing primary materials. Besides, how can one decide whether a societal influence is significant or not without considering the science? For example, Paul Forman’s argument concerning the influence of contemporaneous German culture on the acceptance of the Uncertainty Principle in quantum theory is interesting, but pays little attention to physics; a physicist might point out that it quickly became clear to the quantum theorists (many of whom were not German) that the Uncertainty Principle arose inevitably from wave-particle duality in all three formulations of the theory (see Hendry on this for example).

Indeed, now that it is accepted one needs to consider both internal and external factors in studying a given scientific advance, it’s not obvious to me what the professionalization of science history should look like, i.e., how the next generation of science historians should be trained. In the meantime, I think there is a good argument for the use of multi-disciplinary teams of collaborators in the study of the history of science.

All in all, a very enjoyable conference. I wish there had been time to relax and have a swim in the bay, but I never got a moment. On the other hand, I managed to stock up on some free issues of my favourite publication in this area, the European Physical Journal (H).  On the plane home, I had a great read of a seriously good EPJH article by S.M. Bilenky on the history of neutrino physics. Consider me inspired….

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Filed under History and philosophy of science, Third level, Travel

Remembering Stephen Hawking

Like many physicists, I woke to some sad news early last Wednesday morning, and to a phoneful of requests from journalists for a soundbyte. In fact, although I bumped into Stephen at various conferences, I only had one significant meeting with him – he was intrigued by my research group’s discovery that Einstein once attempted a steady-state model of the universe. It was a slightly scary but very funny meeting during which his famous sense of humour was fully at play.

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Yours truly talking steady-state cosmology with Stephen Hawking

I recalled the incident in a radio interview with RTE Radio 1 on Wednesday. As I say in the piece, the first words that appeared on Stephen’s screen were “I knew..” My heart sank as I assumed he was about to say “I knew about that manuscript“. But when I had recovered sufficiently to look again, what Stephen was actually saying was “I knew ..your father”. Phew! You can find the podcast here.

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Hawking in conversation with my late father (LHS) and with Ernest Walton (RHS)

RTE TV had a very nice obituary on the Six One News, I have a cameo appearence a few minutes into the piece here.

In my view, few could question Hawking’s brilliant contributions to physics, or his outstanding contribution to the public awareness of science. His legacy also includes the presence of many brilliant young physicists at the University of Cambridge today. However, as I point out in a letter in today’s Irish Times, had Hawking lived in Ireland, he probably would have found it very difficult to acquire government funding for his work. Indeed, he would have found that research into the workings of the universe does not qualify as one of the “strategic research areas” identified by our national funding body, Science Foundation Ireland. I suspect the letter will provoke an angry from certain quarters, but it is tragically true.

Update

The above notwithstanding, it’s important not to overstate the importance of one scientist. Indeed, today’s Sunday Times contains a good example of the dangers of science history being written by journalists. Discussing Stephen’s 1974 work on black holes, Bryan Appleyard states  “The paper in effect launched the next four decades of cutting edge physics. Odd flowers with odd names bloomed in the garden of cosmic speculation – branes, worldsheets , supersymmetry …. and, strangest of all, the colossal tree of string theory”.

What? String theory, supersymmetry and brane theory are all modern theories of particle physics (the study of the world of the very small). While these theories were used to some extent by Stephen in his research in cosmology (the study of the very large), it is ludicrous to suggest that they were launched by his work.

 

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Filed under Cosmology (general), History and philosophy of science, Science and society, Teaching, Third level