Historical research guide · 0432 · 2021
A brief history of ball lightning observations by scientists and trained professionals
Alexander G. Keul
In one minute
Ball lightning is an atmospheric-physics problem with thousands of reports but very few instrumented observations. Alexander Keul narrows the evidence question by collecting observations made by scientists and trained professionals. His 2021 review describes 41 cases from eight countries, dated 1868–2020, then reports their sizes, durations, thunderstorm setting and associated lightning. It preserves individual reports separately from derived estimates: Gerlach’s timed 1927 event, material traces such as melted asphalt and altered air samples, and a 2012 spectroscopic recording near a power-line tower. The article does not claim one mechanism. It proposes a shared database that keeps observations, physical traces and recordings available for comparison with competing explanations and laboratory simulations.
Connection
Chapter 9 treats plasmoids and glowing orbs as real physical objects worth instrumenting rather than as stories, and this is the closest thing the field has to a witness ledger kept by people trained to observe and to estimate. Chapter 1’s evidence ladder gets its rungs here too: an anecdote, a timed measurement and a captured air sample are three different kinds of evidence, and Keul keeps them apart.
From the source
The compiled sample of 41 cases by trained observers, 1868 to 2020 and eight countries, gives reported sizes from 1.5 cm to 15 m with the mode under 20 cm, durations from 1.5 to 180 seconds with a mean of 19.5 s and a median of 4 s, and 73 per cent of events occurring inside a thunderstorm with 41 per cent of witnesses reporting a simultaneous stroke.Section 5, Synopsis of cases; Table 1
Correlating 34 central European ball lightning events from 1994 to 2016 against the Austrian lightning location system, Keul and Diendorfer found 19 of the time-correlated strokes positive, 4 to 370 kA, and 15 negative — an unexpectedly high positive fraction against the 17 per cent of positive cloud-to-ground strokes recorded in Austria over a decade.Section 2, final paragraph; Section 4.2, Vienna 2020 case
Walther Gerlach, timing the thunder of the 9 May 1927 Tübingen event, put the object’s path at 1300 plus 1150 metres in about 2 seconds, a mean speed near 1200 metres per second — roughly Mach 3.6, and the flight was soundless, with no sonic boom.Section 3.1, Gerlach 1927
Several cases left measurable physical traces: Wittmann calculated at least 1.9 times 10 to the 7th joules per cubic metre from the melted asphalt patches at Neustadt in 1951; the Dorstone water tub implies at least 2 times 10 to the 3rd joules per cubic centimetre; Dmitriev’s four air samples taken 55 to 70 seconds after a passage held ozone and nitrogen dioxide 50 to 100 times above normal air.Sections 3.1, 3.2 and 6
Cen and colleagues recorded a 1.64-second event at Xining in 2012 with two slitless-spectroscopy video cameras: the object formed from a cloud-to-ground channel on the ground near a power-line tower, and its spectrum showed iron, calcium, silicon, nitrogen and oxygen lines, consistent with the Abrahamson and Dinniss soil-strike theory.Section 6, Cen et al. 2014
Keul’s closing proposal is a coordinated one: benchmark physical-evidence cases such as the Dorstone tub, the Poughquag glass and the Qinghai spectrum, plus digital material from phones and webcams, assembled into a database against which ball lightning theories and laboratory simulations can be critically assessed.Section 7, Conclusions
The way in
https://doi.org/10.5194/hgss-12-43-2021How to cite it
Alexander G. Keul (2021) A brief history of ball lightning observations by scientists and trained professionals doi:10.5194/hgss-12-43-2021