Editing Ball lightning (section)

=== Hydrodynamic vortex ring antisymmetry ===
One theory that may account for the wide spectrum of observational evidence is the idea of [[combustion]] inside the low-velocity region of spherical [[vortex]] breakdown of a natural vortex{{vague|date=July 2012}} (e.g., the '[[Hill's spherical vortex]]').<ref>{{cite journal | last = Coleman | first = PF | year = 1993 | journal = Weather | volume = 48 | issue = 1 | page = 30 | title = An explanation for ball lightning? | doi = 10.1002/j.1477-8696.1993.tb07221.x|bibcode = 1993Wthr...48...27. }}</ref>