Lightning ball: experiments on creation and hypotheses (comment on “Energy density calculations for ball-lightning-like luminous silicon balls” by G. S. Paiva, J. V. Ferreira, C. C. Bastos, M. V. P. dos Santos, A. C. Pavao)

The problems addressed in this paper include estimating: the energy density of luminous silicon balls, the density range of a natural lightning ball, and whether and how the object created and described in the commented paper (Usp. Fiz. Nauk 180 218 (2010) [Phys. Usp. 53 (2) (2010)]) corresponds to the natural phenomenon.