Comments, with reply, on `Planetary influences on electrical engineering´ by R.N. Bracewell

The commenter adds an example of the influence of astronomy on electrical engineering to those that appear in the above-titled paper (see ibid., vol.80, no.2, p.230-237, 1992). He points out that except for a factor of approximately 10, Bode´s law of planetary orbit radii is quite similar to Bessel function radial units of first-order cylinder functions of the first kind, such as appear in harmonic microwave cavities used in electrical engineering. In his reply, the author presents another example of an electrical topic with roots in astronomy: the problem of determining dynamical stability by examining the differential equation of the motion, a basic part of modern stability and control theory in the electrical engineering curriculum that was first attacked by Isaac Newton in connection with the stability of planetary orbits