Ball lightning is a rare and unexplained phenomenon described as luminescent, spherical objects that vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, the observed phenomenon is reported to last considerably longer than the split-second flash of a lightning bolt, and is a phenomenon distinct from St. Elmo’s fire.
Some 19th-century reports describe balls that eventually explode and leave behind an odor of sulfur. Descriptions of ball lightning appear in a variety of accounts over the centuries and have received attention from scientists.
a written or spoken description of sth that has happened 描述；叙述；报告
She gave the police a full account of the incident.
她向警方详尽地叙述了所发生的事情。
An optical spectrum of what appears to have been a ball lightning event was published in January 2014 and included a video at high frame rate.
Laboratory experiments have produced effects that are visually similar to reports of ball lightning, but how these relate to the supposed phenomenon remains unclear.
https://www.youtube.com/watch?v=dMsGHmGxyxo
Ball lighting is not an optical phenomenon. It is a re real thing and it’s caused by intense thunderstorms.
Ball lightning has been one of the most mysterious natural phenomena for centuries, partly because it is so rare and transient and therefore hard to investigate. But a fortuitous observation during field experiments in China to study ordinary lightning, reported in Physical Review Letters, has now provided what seems to be the first measurement of the emission spectrum of ball lightning. The data suggest that the glowing ball was composed of elements from soil, consistent with one popular theory.