Kinematics and Dynamics

Extract

I would probably not be mistaken in saying that for the first time in the practice of solid scientific meetings the problem of the dynamics of planetary nebulae has become a subject of broad and sufficiently many-sided discussion. At the same time, I am inclined to estimate the successes achieved at the present symposium as more than modest. However, there have been no sensations. To the contrary of diminishing the importance and value of the reports made here, I only want to underline the fact that despite its attractiveness, the problem of the dynamics of planetary nebulae remains as before one of the difficult and complicated fields of theoretical and practical astrophysics. It cannot be solved without the cooperation of contiguous branches of science, particularly gas dynamics, magnetohydrodynamics and others. These are new components without which the physics of planetary nebulae has, nevertheless, managed. At the same time, almost all of the physics of planetary nebulae is comprised in the problem of the dynamics. Finally, the problems of the dynamics of planetary nebulae cannot be solved in an approach detached from the problem of the origin of planetary nebulae themselves and also from the origin and development of their nuclei. In this sense, the dynamics of planetary nebulae is becoming to a certain degree a cosmogonic science.