User Tools

    To create and edit articles, please register and log-in

Main Menu : categories & index etc.

Main menu
Click categories to expand

A-Z listingplugin-autotooltip__plain plugin-autotooltip_bigA-Z listing

This is an alphabetical index of all content pages.

Other categories



Also see

Importance Ratings
Curator's rationale
AI Policy

Twitter feed 𝕏

Feeds + s.e.o. etc.
rss / xml feed
sitemap file
A-Z listing (archived)

Indexed under : Earth Sciences

Wikenigma - an Encyclopedia of Unknowns Wikenigma - an Encyclopedia of the Unknown


High powered lightning discharges are happening somewhere on Earth 100 times every second.

A possible mechanism for the very substantial electrical charges within the clouds was put forward in 1978. Following lab-based experiments, it was suggested that the charges arise from the static-electric interactions of graupel (slush) and ice crystals moving within the cloud (due to convection currents caused by widely differing air temperatures) .

See : Journal of the Atmospheric Sciences Volume 35: Issue 8.

Since then however, tests performed on atmospheric thunder clouds have shown that the charges are far higher than would be expected - as yet there are no agreed explanations as to how or why.

One mystery is how thunderclouds become so highly charged. The best explanation is that collisions between small ice particles and heavier gobs of slush called graupel tend to transfer electrical charge, but the role of this process in real clouds is not proven.“
An even bigger puzzle is how the huge current of a lightning bolt ever begins to flow when air is an electrical insulator. It is possible to make air break down to form a conducting plasma, but this requires a fearsomely intense electric field of more than a million volts per metre. Although meteorologists have sent hundreds of instrument-laden balloons and rockets into thunderclouds to test local conditions, the strongest fields they have seen are only about a tenth of that critical value.”

Source : New Scientist, Feb. 2012 Strange skies: Lightning should be impossible
Although we've been sending balloons and aircraft into lightning-charged thunderstorms since the 1950s, we haven't observed that 3 million volts per metre electric field needed to cause breakdown. Instead, the field is typically 10 times weaker than the ones we generate [by walking] on deep pile carpets“

Source : New Scientist, 15 April 2017 'Bolt from the blue: Lightning doesn’t form like we thought'

Figures for the apparent (lack of) voltage anomaly are provided in a 2016 paper for the Journal of Geophysical Research - see:Positive streamer initiation from raindrops in thundercloud fieldsOpen Access

The threshold field for the electric gas discharge in air is ≈26 kVcm−1atm−1, yet the maximum field measured (from balloons) is ≈3 kVcm−1atm−1. The question of how lightning is stimulated is therefore one of the outstanding problems in atmospheric electricity.”

The authors conclude that other as-yet-undocumented mechanisms may be operating :

Such mechanisms could be electric field space variations via collective effects of many hydrometeors or runaway breakdown.“

The possibility that high energy electrons (linked to cosmic rays originating in deep space) may trigger (or facilitate) the path of lightning strikes is still being debated.


[1] The World Wide Lightning Location Network (WWLLN) publishes daily updated maps of major lightning hits across the world.

[2] Lightning discharges also commonly occur near volcanic eruptions. It's thought that ice crystals may also play a part in the generation of the electricity. Other theories include colliding dust particles, radioactive effects, rock fragmentation, etc etc. See Wikipedia

Also see Terrestrial gamma-ray flashesplugin-autotooltip__plain plugin-autotooltip_bigTerrestrial gamma-ray flashes

Terrestrial gamma-ray flashes (TGFs) were first reported using data from the Burst and Transient Source Experiment (BATSE) onboard NASA's Compton Gamma-Ray Observatory (CGRO) in 1994.

The short duration (0.2 to 3.5 milliseconds) atmospher…
and Ball Lightningplugin-autotooltip__plain plugin-autotooltip_bigBall Lightning

Ball Lightning refers to luminous, usually spherical, atmospheric objects which vary from a few centimetres to several metres in diameter. They are usually associated with thunderstorms. Anecdotal reports suggest that they can 'pass through' solid object…
and Static electricityplugin-autotooltip__plain plugin-autotooltip_bigStatic electricity

Static electricity has been investigated for more than 2 thousand years. The earliest written scientific accounts of 'static electricity' are believed to be those of Thales of Miletus at around 600BC. He thought (correctly, but for the wrong reasons)…

    Please share this page to help promote Wikenigma !

Dear reader : Do you have any suggestions for the site's content?

Ideas for new topics, and suggested additions / corrections for older ones, are always welcome.

If you have skills or interests in a particular field, and have suggestions for Wikenigma, get in touch !

Or, if you'd like to become a regular contributor . . . request a login password. Registered users can edit the entire content of the site, and also create new pages.

( The 'Notes for contributors' section in the main menu has further information and guidelines etc.)

Automatic Translation

You are currently viewing an auto-translated version of Wikenigma

Please be aware that no automatic translation engines are 100% accurate, and so the auto-translated content will very probably feature errors and omissions.

Nevertheless, Wikenigma hopes that the translated content will help to attract a wider global audience.

Show another (random) article

Further resources :