Session J5: History of Physics

Impact of WWI on Relativity and Other Sciences

Custom calls WWII the physicists' war (radar, nuclear bombs, rockets) and WWI the chemists' war (nitrogen fixation and synthetic fuels as well as poison gases). In fact both wars affected all of science profoundly. For us, hostilities began with the capture of Erwin Freundlich's German eclipse expedition to the Crrimea in August 1914. Curioiusly they had gone there to measure deflection of starlight be the sun at the half-of-GR level predicted earlier by Einstein. The end came in 1919 with the founding of the IAU (Central Powers strictly excluded; indeed Germany did not join until after WWII) and the Eddington-Dyson-Crommelin eclipse expedition that did record the deflection. In between were many deaths (Moseley and Karl Schwarzschild perhaps best know), turning of observatory optical shops to making binoculars, periscopes, etc, and twisting of careers (including probably the origin of the Hubble-Shapley enmity, when the former volunteered and the latter went directly to a job at Mt. Wilson; Lemaitre is another interesting case). There will be a small prize for the first person to identify the gentleman who refereed my second thesis paper, who served the full four years, partly in the trenches, on the German side.   

Spin Dynamics of Kelvin's Pebbles, Jellett's Eggs, and Shiva's Lingam Stones

Study of the problem of the rise of the center of mass (COM) of spinning objects is said to have begun in the late nineteenth century. These early mathematical treatments aimed to explain the motion of the newly invented and patented ``tippe top.'' This semi-spheroidal top will invert when spun on a smooth surface while raising its COM. Because of the importance of friction in their dynamics, such non-holonomic systems are not readily amenable to analytic treatment, or of intuitive understanding. In notes written in 1844 - before the invention of the tippe top - Lord Kelvin (William Thomson) discussed the problem of the rising COM of spinning objects. He experimented with both oblate and prolate ellipsoidal pebbles, but did not publish a complete theoretical treatment of the problem. J. H. Jellett, in his 1872 book ``Theory of Friction,'' provided a partial account of the related problem of the rise of the COM for an egg-shaped (ovoid) object, making use of a new (adiabatic) invariant of the motion that he devised. Naturally occurring prolate ellipsoidal ``Lingam stones'' from the Narmada River in India exhibit similar counter-intuitive dynamical behavior. When spun around its minor axis in a horizontal plane, a Lingam stone will stand erect and spin around its major axis in a vertical position. This presentation will explore the history and some of the experimental facts and theoretical ideas about the rotational dynamics of such physical objects.   

Anticipations of dark energy in the work of Schr\"{o}dinger

I'll examine the advocacy by Schr\"{o}dinger of a cosmological constant, or its equivalent, beginning with his 1917 paper ``Concerning a System of Solutions to the Generally Covariant Equations for Gravitation,'' and continuing with his efforts in the 1940s toward a unified field theory. I'll discuss Schr\"{o}dinger's idea that electromagnetism as well as gravitation was attenuated at long distances due to such a construct. I'll remark how these ideas anticipated modern discussions about dark energy.   

The curious incident of Wheeler's $\delta$-rays

John Wheeler is well-known for his bold ideas and proposals (``daring conservatism"), which he usually promoted vigorously and repeatedly. Even those that ultimately did not pan out contain important lessons. A curious exception was his idea of so-called $\delta$-rays, which he proposed at the important First Texas Symposium on Relativistic Astrophysics (December 1963). But he did not include this idea in the proceedings of the symposium and apparently never elaborated it subsequently. The only record in print is a one-sentence mention in Hong-Yee Chiu's {\it Report on the Texas Symposium}.\footnote{Quasi-Stellar Sources and Gravitational Collapse, Including the Proceedings of the First Texas Symposium on Relativistic Astrophysics, University of Chicago Press (1965), p. 13} What was that proposal, and why did it quickly disappear from the scene? I will present one record of what Wheeler said at the Symposium.