his NASA publications Evolution of the Solar System. After criticising the "Inadequacy of the Homogeneous Disc Theory", he writes: ".. it is more attractive to turn to the alternative that the secondary bodies derive from matter falling in from "infinity" (a distance large compared to. the satellite orbit). This matter (after being stopped and given sufficient angular momentum) accumulates at specific distances from the central body. Such a process may take place when atoms or molecules in free fall reach a kinetic energy equal to their ionization energy. At this stage, the gas can become ionized by the process discussed in sec. 21.4; the ionized gas can then be stopped by the magnetic field of the central body and receive angular momentum by transfer from the central body as described in sec. 16.3.". Notes Other references Brenning, N . A comparison between laboratory and space experiments on Alfven's CIV effect, in IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. 20, no. 6, p. 778-786. (1996) Review of the CIV phenomenon, in Space Science Reviews (ISSN 0038-6308), vol. 59, Feb. 1992, p. 209-314. (1992) Limits on the magnetic field strength for critical ionization velocity interaction, Physics of Fluids'' -- November 1985—Volume 28, Issue 11, pp. 3424–3426 Astrophysics Plasma physics