ball-lightning.unexplained.im
Ball lightning, checked.
A rare, lingering glow that people report in thunderstorms: what the reports describe, where good sources disagree, and the one well-instrumented natural event recorded in 2012.
Ball lightning, also called globe lightning, is a rare aerial phenomenon in the form of a luminous sphere that is generally several centimetres in diameter. Britannica
The Met Office describes ball lightning as an incredibly rare form of lightning in which a persistent and moving luminous white or coloured sphere is seen. Met Office
The Royal Meteorological Society says it is estimated that only one in a million lightning strikes produces the ball lightning phenomenon. RMetS Despite that estimate, the same RMetS article says there are more than 10,000 written accounts of the bright, spherical lights in the sky, which linger for seconds longer than a true lightning bolt. RMetS
In a paper published on 17 January 2014, Jianyong Cen, Ping Yuan and Simin Xue reported that ball lightning was observed with two slitless spectrographs at a distance of 0.9 km. PRL 2014 The entire luminous duration of the ball lightning was 1.64 s. PRL 2014
Good sources do not all agree on a typical size, on which idea is "leading," or even on how sure anyone should be that the phenomenon exists. Those notes are on the pages, not hidden in a footnote.
How big, and for how long?
Good sources do not give one settled typical size or lifetime. Encyclopaedia Britannica says ball lightning is generally several centimetres in diameter and normally lasts only a few seconds. The Royal Meteorological Society, citing other accounts, says it ranges from a golf ball to a small car and lasts between a few seconds and a couple of minutes. Abrahamson and Dinniss, writing of an “average” ball lightning, give a diameter of 300 mm and a lifetime of about 10 s. Cen, Yuan and Xue, summarising earlier reports, give a diameter between 1 and 100 cm, and their own 2012 event lasted 1.64 s. This site sets the figures side by side and does not pick a single typical size or time.
Start here
What is ball lightning?
What reports describe, and how that differs from bead lightning and ordinary fork lightning.
Reports
A 2013 Cumbria account, Uppsala in 1944, and the 1638 Widecombe storm, with the hedges kept.
Theories
Masers, glowing soil particles, and why this site does not crown a single leading idea.
The 2012 spectrum
One natural event on the Qinghai Plateau, recorded with spectrographs 0.9 km away.
In the laboratory
Short-lived plasmas, a Tesla story that cannot be repeated from his notes, and a frank "not lightning."
Things it is not
Bead lightning, St Elmo's fire, and the sceptical after-image idea.
Myths
The 1753 Richmann death, and other stories that get ahead of the evidence.
Games
A short sourced quiz and a myth-or-fact set.
Ball lightning printables
Fact-checked PDFs in A4 and US Letter, sold as instant downloads from the ReallyByte store: our own drawings, a guide, and worksheets with answers. Prices in US dollars.
The Ball Lightning Reference Guide
A fact-checked guide to what reports describe, where good sources disagree on size and theories, and the 2012 spectrum recorded in Qinghai, with our own drawings.
The Ball Lightning Activity Pack
A quiz, myth-or-fact cards and worksheets with answers, following the sourced wording used on ball-lightning.unexplained.im.
Reports, Theories and the 2012 Spectrum
A short sourced companion to famous reports, the leading hypotheses, and the one well-instrumented natural event of 23 July 2012.
The Complete Ball Lightning Printables Bundle
All three packs, A4 and US Letter, at a bundle price.