R.I.P. John M Stewart (1943-2016)

john-stewartI was very sad this morning to hear of the death of distinguished mathematical physicist Dr John M. Stewart (left). Apart from a few years in Munich in the 1970s John Stewart spent most of his working life in Cambridge, having studied there as an undergraduate and postgraduate and then returning from his spell at the Max Planck Institute to the Department of Applied Mathematics and Theoretical Physics for forty years.

John’s research mostly concerned relativistic fluid dynamics. Indeed, he was one of the pioneers of numerical relativity in the United Kingdom, and he applied his knowledge to a number of problems in early Universe cosmology and structure formation. I think it is fair to say that he wasn’t the most prolific researcher in terms of publications, which is perhaps why he only got promoted to Senior Lecturer in 2000 and never made it to a Chair, retiring as Reader in Gravitational Physics in 2010. However, his work was always of a very high technical standard and presented with great clarity and he was held in a very high regard by those who knew him and worked with him.

The tributes paid to John Stewart by King’s College (of which he was a Life Fellow) here and his colleagues in the Centre for Theoretical Cosmology here give a detailed account of his research achievements, so I refer you to them for more information about that aspect of his career.

I just wanted to add a personal note not about John Stewart’s research, but about something else mentioned in the obituaries linked to above: his teaching. I was fortunate enough to have him as a lecturer when I was studying Natural Sciences at Cambridge during the early 1980s. In the second year (Part IB) I specialised in Physics and Mathematics, and John taught part of the Mathematics syllabus. He was an absolutely superb teacher. For a start he was superbly well organized and had clearly thought very deeply about how best to present some quite difficult material. But it wasn’t just that. He projected a very engaging personality, with nice touches of humour, that made him easy to listen. His lectures were also very well paced for taking notes. In fact he was one of the few lecturers I had whose material I didn’t have to transcribe into a neat form from rough notes.

I have kept all the notes from that course for over thirty years. Here are a couple of pages as an example:


Anyone who has ever seen my handwriting will know that this is about as neat as I ever get!

When I was called upon to teach similar material at Cardiff and Sussex I drew on them heavily, so anyone who has learned anything from me about complex analysis, contour integration, Green’s functions and a host of other things actually owes a huge debt to John Stewart. Anything they didn’t understand was of course my fault, not his..

I also remember that John came to Queen Mary to give a seminar when I worked there in the early 90s as a postdoc. I was still a bit in awe of him because of my experience of him in Cambridge. His talk was about a method for handling the evolution of cosmological matter perturbations based on an approach based on the Hamilton-Jacobi formalism. His visit was timely, as I’d been struggling to understand the papers that had been coming out at the time on this topic. In the bar after his talk I plucked up the courage to explain to him what it was that I was struggling to understand. He saw immediately where I was going wrong and put me right on my misconceptions straight away, plucking a simple illustrative example apparently out of thin air. I was deeply impressed, not only by his ability to identify the issue but also with his friendly and helpful demeanour.

Rest in Peace, Dr John M. Stewart (1943-2016).

10 Responses to “R.I.P. John M Stewart (1943-2016)”

  1. Clare Burrage Says:

    I remember very clearly a GR problem sheet from John’s course, where he assured us that he could answer every problem in less than a page. It took me, pages and pages and pages to get to the same answers. He *always* had a nice simple example that got straight to the heart of the problem.

  2. George Jones Says:

    I just pulled his nice little book “Advanced general relativity” off my bookshelf, and I see that I purchased it in January, 1994. The years fly.

  3. Adrian Burd Says:

    That’s sad news. I was in John’s Advanced General Relativity course when taking what was then the Part III of the Math Tripos. I agree, he was an excellent teacher, and a very insightful scientist.

  4. George Efstathiou Says:

    As a colleague, I will miss John. In addition to his work on GR,
    in retirement John became interested in Python. His
    book, ‘Python for Scientists’ is typically concise and elegant.
    As Peter said, he was very smart and a good sense of humour.
    A genuinely nice guy.

  5. Anton Garrett Says:

    I have two memories of John Stewart.

    First was when taking the then very unusual Part III maths course, having graduated in physics, in the first term of the 1978/9 academic year. John’s GR course began with 5 or 6 lectures on the differential geometry involved, taking a very pure mathematical axiomatic viewpoint. I was not convinced that this was particularly enlightened course design given that many people came to Part III from physics courses at various universities. But he certainly lectured the material clearly.

    My second, happier, memory, was when several years later I was myself lecturing the plasma physics option in Maths Part III, and he held a social for Part III lecturers and students in his rooms in King’s. My memories of it are hazy for the best of reasons.

    I am sorry we have lost him.

    • John Peacock Says:


      My experience was exactly the same as yours (in 77/78): I gave up Stewart’s course after about 5 lectures because I got impatient that we were 1/4 through the course and hadn’t done any relativity yet. It would have done me good to have stuck with it, no doubt. But Part III had an “M” in it, not a “P”, so there was no reason to expect any concessions to those with lower mathematical standards, I suppose. Still, I remain unhappy when I see books on GR that insist you have to use only the differential geometry language – at least at an introductory level. It just makes many things seem more complicated than they really are.

      • Anton Garrett Says:

        Einstein: “Since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore.”

        (From: In A. Sommerfeld “To Albert Einstein’s Seventieth Birthday” in Paul A. Schilpp (ed.) Albert Einstein, Philosopher-Scientist, Evanston, 1949.)

      • I didn’t do Part III so can’t comment on those lectures but Cambridge wasn’t the only place where GR was spoilt by putting the Maths before the Physics.

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