LIGHTNING (Heb. בָּרָק֒, H1398, gleam; בָּזָק, H1027, flash of lightning; חֲזִיז, H2613, to shine, flame, lightning, torch; אﯴר֮, H240, light; Gr. ἀστραπή, G847, lightning). Four different Heb. words and one Gr. word are used to denote lightning, sometimes in a fig. sense. Lightning is used to symbolize God’s awful and glorious majesty (Rev 4:5; 11:19), to describe the brightness of His countenance; as an indication of Christ’s quick and unexpected coming (Matt 24:27; Luke 17:24); and accompanying destructive judgments on the wicked (Rev 8:5; 16:18); and the Lord’s fighting for His people (Zech 9:14). בָּזָק, H1027, “a flash of lightning,” is found in Ezekiel 1:14; בָּרָק֒, H1398, “a gleam of lightning,” is the term most commonly used (Exod 19:16; 2 Sam 22:15; Job 38:35; Ps 18:14; 77:18; 97:4; 135:7; 144:6; Jer 10:13; 51:16; Ezek 1:13; Dan 10:6; Nah 2:4; Zech 9:14). חֲזִיז, H2613, to “shine,” or “torch,” appears in Exodus 20:18, and ’or, “light,” or “luminary,” in Job 37:3. In the NT astrapé “lightning” or “bright,” occurs frequently (Matt 24:27; 28:3; Luke 10:18; 17:24; Rev 4:5; 8:5; 11:19; 16:18).

Lightning refers generally to any and all of the various forms of visible electrical discharge produced by thunderstorms, i.e., a flash of light in the sky caused by an electrical current. The current may flow between a cloud and the earth, between two clouds, or between the charged surfaces of the same cloud. The electrical conditions of the earth’s surface and atmosphere in normal fair weather and in stormy weather differ. The earth has a negative surface charge. In fair weather the electric potential of the atmosphere increases with elevation at the rate of about 100 volts per meter. The earth (negative) and atmosphere (and upper atmosphere, or ionosphere) (positive) thus form a vast electrical condenser.

In a rapidly developing rainstorm, clouds become positively charged at the top and negatively charged below. Clouds consist of an immense number of tiny water droplets, each with a charge on its surface. Meteorologists believe that the clouds become charged due to the differential falling rates of large and very small drops.

Thunderclouds form at the tops of large, moist, rising air currents. Large drops in the cloud, which for some reason become negatively charged, fall due to gravity, whereas, the smaller drops, which become positively charged, can be carried by updrafts to the top of the cloud. (A similar situation has been observed to exist in the spray droplets from a waterfall.) The large drops falling through the rising air currents in the cloud may split into smaller droplets and be carried upward again. The small drops will grow in size while traveling upward due to condensation and accretion. The cloud thus acts as a huge electrostatic machine with a continual process of charging taking place.

It has been estimated that the frequency of lightning over the whole earth averages about 100 flashes every second. This would represent perhaps a discharge rate of four billion kilowatts of continuous electrical power. Some flashes are several m. long with estimated cross-sections of four to six inches. Often several flashes in quick succession produce the illusion of forked lightning. Sheet lightning is merely the scattering of light, or reflection by clouds, of distant flashes.

Bibliography J. Strong, The Exhaustive Concordance of the Bible (1890); M. F. Unger, Unger’s Bible Dictionary (1957); The World Book Encyclopedia (1964); Van Nostrand’s Scientific Encyclopedia, 4th Ed. (1968).