Died: 31 March 1997 in Princeton, New Jersey, USA

Lyman Spitzer Jr. parents were Lyman Strong Spitzer (born 2 February 1880, in Amherst, OH) and Blanche Carey Brumback (born 4 March 1885, in Ohio). His middle name of 'Strong' came from Lyman Strong Spitzer Sr.'s mother Sarah Elizabeth Strong who was married to Adelbert Lorenzo Spitzer. Spitzer Sr. worked in Real Estate in Toledo and later was Manager of a paper and box company. He was a Captain, Quartermaster Corps, during World War I, and almost lived to be 100 years old, dying on 2 April 1979. Lyman Jr. attended Scott High School in Toledo and then studied at Phillips Academy in Andover, Massachusetts, graduating in 1931. In the same year he entered Yale University where, in addition to outstanding academic achievements in physics, he was chairman of The Yale Daily News. He graduated Phi Beta Kappa in 1935 with a Bachelor's degree in physics. Having won a fellowship to St John's College, Cambridge to enable him to study there during the academic year 1935-36, he was taught by Arthur Eddington and was strongly influenced by Subrahmanyan Chandrasekhar who was about four years older than Spitzer.

After his year abroad, Spitzer returned to the United States and entered Princeton University where he earned his Master's degree in 1937. He undertook research for his doctorate under Henry Norris Russell, and received a Ph.D. in astrophysics in 1938. He then was appointed as a postdoctoral fellow at Harvard, spending the academic year 1938-39 there before returning to Yale where he was appointed as an Instructor in 1939. Soon after this he married an archaeologist Doreen D Canaday; they had a son Nicholas C and three daughters, Dionis C, Sarah S and Lydia S.

After the start of World War II, Spitzer left Yale to undertake work to help the war effort. He worked first at the Special Studies Group at Columbia, then did underwater sound research with the Sonar Analysis Group that led the development of sonar. In 1946 he returned to university life, being made an associate professor at Yale. Henry Norris Russell, who had supervised Spitzer's doctoral studies at Princeton, was retiring and Princeton was seeking to fill the Chair of Astronomy. Spitzer applied for the position, beginning his covering letter as follows [3]:-

For many reasons, I believe that the chairmanship at Princeton offers very great opportunities of the sort which interest me, and I would definitely accept an offer from Princeton University if it were along the lines which I visualise, and which I describe below ... The most important aspect of the Princeton opening, from my point of view, is the general policy of the University administration towards the Astronomy Department.

My own respect for the astronomy at Princeton in general and for Professor Russell in particular, is so profound that it would be a great personal pleasure for me to come to Princeton under almost any conditions. The very strong support which astrophysics enjoys at Yale, however, would make it very difficult for me to leave New Haven with its effective opportunities for effective research and growth unless the corresponding opportunities at Princeton are at least as great.

He was appointed to the chair and took up the position in the spring of 1947. He also became the director of Princeton's Observatory. In the second half of the 1940s Spitzer became interested in space astronomy. He explained in [L Spitzer, Dreams, stars, and electrons, Annual Reviews of Astronomy and Astrophysics 27 (1989), 1-.]:-

As World War II drew to its end, I was approached by a friend on the staff of the RAND corporation, an Air Force 'think-tank'. He told me that his group was carrying out a secret study of a possible large artificial satellite to circle the earth a few hundred miles up. "Would you be interested," he asked me, "in writing a chapter on how such a satellite might be useful in astronomy?" With my long and ardent background in science fiction, I found this invitation an exciting one and accepted with great enthusiasm.

His involvement in space astronomy has made Spitzer well known by the general public, but he made many other highly significant advances. One area which he founded is the study of the interstellar medium consisting of gas and dust between the stars from which new stars are formed. It was the realisation that the bright stars in spiral galaxies had formed relatively recently from the dust and gas seen in these galaxies which first led him to this work. He described his later significant contributions to this area in his book Diffuse Matter in Space (1968).

Another area to which he made major contributions was plasma physics. He founded the Princeton Plasma Physics Laboratory (initially called Project Matterhorn) in 1951 which studied how nuclear fusion could be harnessed to give clean energy. He was the first director of the Laboratory, continuing in this role until 1967. He described his contribution to plasma physics in Physics of Fully Ionized Gases (1956). W P Allis, reviewing the book, writes:-

This book starts with particle orbits in crossed electric and magnetic, and in inhomogeneous magnetic fields. This approach is necessary in discussing containment by magnetic mirrors and the lack of it in a simple torus. A rapid treatment of the Boltzmann equation, in an appendix, brings us in Chapter 2to the transport equation for a fluid. This is joined with Maxwell's equations, and the simple limits of high and low magnetic fields are briefly considered. There is a chapter on ... magnetohydrodynamics, and one on waves .... The best chapter deals with encounters between charged particles and the resultant macroscopic phenomena: diffusion, electrical and thermal conductivities, relaxation times for densities and energies. This summarizes some of the author's own researches and the results in that chapter are frequently referred to in papers.

Two years later Spitzer published the paper The stellarator concept describing further results from his Laboratory. He introduced the paper by writing:-

The basic concepts of the controlled thermonuclear program at Project Matterhorn, Princeton University, are discussed. In particular, the theory of confinement of a fully ionized gas in the magnetic configuration of the stellarator is given, the theories of heating are outlined, and the bearing of observational results on these theories is described.

He then goes on to give further details:-

Magnetic confinement in the stellarator is based on a strong magnetic field produced by solenoidal coils encircling a toroidal tube. The configuration is characterized by a 'rotational transform', such that a single line of magnetic force, followed around the system, intersects a cross-sectional plane in points which successively rotate about the magnetic axis. A theorem by Kruskal is used to prove that each line of force in such a system generates a toroidal surface; ideally the wall is such a surface. A rotational transform may be generated either by a solenoidal field in a twisted, or figure-eight shaped, tube, or by the use of an additional transverse multipolar helical field, with helical symmetry.

The third area which Spitzer helped to shape is that of stellar dynamics. The idea of 'relaxation' had been defined by Chandrasekhar but it was the work of Spitzer which clarified how [3]:-

... this leads to a stellar structure to approach a singular state, as the effective conduction of heat outward in the star cluster (caused by gravitational interactions between pairs of stars) forces the inner parts to contract more and more rapidly.

As with the other areas, he wrote up his contributions as a book, Dynamical evolution of globular clusters (1987).

In 1952, Spitzer was named the Charles A Young Professor of Astronomy at Princeton. He was president of the American Astronomical Society (1958-60) and chair of the Space Telescope Institute Council (1981-90). He received many honours including: the Henry Norris Russell Prize from the American Astronomical Society (1953), the award of the Bruce Medal of the Astronomical Society of the Pacific (1973) and the Henry Draper Medal of the National Academy of Sciences (1974). He was awarded the James Clerk Maxwell Prize for Plasma Physics by the American Physical Society (1975), and the Gold Medal of the Royal Astronomical Society (1978). In 1979 he received the National Medal of Science, then in 1985 the Crafoord Prize of the Royal Swedish Academy of Sciences for [2]:-

Fundamental pioneering studies of practically every aspect of the interstellar medium, culminating in the results obtained using the Copernicus satellite.

He was elected a fellow of the Royal Society of London in 1990.

Spitzer had the vision to propose a space telescope in 1946 and was, of course, much involved with the Hubble Space Telescope. He continued working right up to the day of his death. In fact he was analyzing results from the Hubble Space Telescope in his office at Princeton on that day, then died suddenly of heart failure in his home.

We should mention one further mathematical contribution made by Spitzer. In 1938 he published the humorous article A contribution to the mathematical theory of big game hunting in the American Mathematical Monthly under the pseudonym H Pétard. This article has been a continuing source of amusement to mathematicians and has led to a number of further amusing articles developing Spitzer's idea.

The proposal that the Space Infrared Telescope Facility (SITF) be named the Spitzer Deep Space Observatory was made by Jay Stidolph who wrote:-

Articles:

1. J N Bahcall, Lyman Spitzer Jr., Physics Today 50 (10) (1997), 123-124.
2. G Gaham, The Crafoord Prize 1985 in Astronomy to Professor Lyman
3. Spitzer Jr., Physica Scripta T11 (1985), 3-4.
4. J P Ostriker, Lyman Spitzer, Biographical Memoirs of Fellows of the Royal Society 53 (2007), 339-348.
5. W Saxon, Lyman Spitzer Jr. Dies at 82; Inspired Hubble Telescope, New York Times (2 April 1997).