Published online by Cambridge University Press: 22 September 2016
My interest in the origin of planetary nebulae goes back to 1967 when I proposed that the envelopes of giants with degenerate carbon-helium cores were dynamically unstable and would be completely ejected to form a planetary nebula. Essentially the same proposal was made almost simultaneously by Lucy (1967) and Paczyński (1967). For some years after that I worked on the dynamical ejection with W. van der Reijden, but for the last few years my interests have been in other areas, principally solar physics and gravitation theory. What then can I contribute to a discussion on Planetary Nebulae? Not a detailed review of work in this area; for that, the reader is referred to review articles by Salpeter (1971), Osterbrock (1973) and Miller (1974).