  The American physicist Robert Dicke (1916-1997) is primarily known for his
important contributions to gravitation, cosmology, and microwave physics. Much
less known is his work in geophysics and related areas of the earth sciences in
which he engaged himself and several of his collaborators in the period from
about 1957 to 1969. Much of Dicke's work in geophysics was motivated by his
wish to obtain evidence in support of the non-Einstenian Brans-Dicke theory of
gravitation. The idea of a decreasing gravitational constant, as entertained by
Dicke and some other physicists (including Pascual Jordan), played some role in
the process that transformed the static picture of the Earth to a dynamical
picture. It is not by accident that Dicke appears as a minor actor in histories
of the plate tectonic revolution in the 1960s.
