Electricity in Nature: Lightning

 

Welcome to the first of what will be a five-part series on Electricity in Nature! Today’s topic is lightning.

We’re all familiar with lightning, though some of us are more afraid of it than others (but not me… no sirree, I’m not scared…), but there is still so much to learn about this incredible natural phenomenon. For example, do you know:

- Why we see lightning during volcanic eruptions?

If you saw photos of the eruption of Icelandic volcano Eyjafjallajökull that erupted in 2010, you may have seen lightning within the plumes of smoke and thought that they surely must be photoshopped. Not so!

There is still research being conducted into the definitive cause behind lightning within the smoke plumes of volcanoes, but the general consensus involves, of all things, dust. The idea is that dust/smoke/ash particles carry small charges that become amplified during the chaos of rushing out of a volcano. With every collision of one particle with another, the charges become more and more polarized until lightning is inevitable because the polarization becomes too great for the air to resist the flow of electricity. The lightning neutralizes the charge separation, essentially relieving the tension of polarization.

credit: National Geographic

There is another lesser known type of volcanic lightning, however, which occurs right at the mouth of the volcano and is much less orderly (not the ordinary branching, bolting lightning we’re used to seeing), manifesting as chaotic sparks probably  as the result of a heavy charge within the volcano itself.

- How many different kinds of lightning there are?

The answer to this question depends on who you ask, and what you consider a “kind” of lightning. The typical classifications are as follows:

Cloud-to-cloud (intercloud, which is lightning moving between separate clouds, and intracloud, which is lightning moving within the same cloud).

credit: Squidoo

Cloud-to-ground (Less common but more dangerous than cloud to cloud. If anything on the earth is struck by lightning, it was cloud-to-ground.) Cloud-to-ground lightning is more complex than a simple bolt shooting straight from a cloud, however, and includes charges moving up and down from both the cloud and the ground.

credit: NOAA Photo Library

Cloud-to-sky (Also known as sprites, cloud-to-sky lightning occurs in the upper atmosphere. They lack the hot temperatures of other types of lightning, and usually have a reddish-orange hue.)

credit: Wikipedia Commons

Lightning is also sometimes further specified as:

Ribbon lightning (Successive strokes of lightning are displaced by wind, resulting in a broadened appearance, almost like a double-exposed photo).

credit: Storm Highway

Bead lightning (The decay of the luminosity of the bolt of lightning, resulting in a beaded appearance. This happens very quickly and is difficult to capture.)

credit- meteoros.de

St. Elmo’s Fire This is not actually lightning, but often closely associated with it and seen during electrical storms. St. Elmo’s Fire (not to be confused with ball lightning as it often is) is the result of a gap in electrical charge. It’s made of plasma (ionized air that emits a glow) and, while lightning is the movement of electricity from a charged point, St. Elmo’s Fire is a coronal discharge that sparks up in the place where there is a drastic difference in charge between the air and an object like the mast of a ship or the steeple of a church. St. Elmo’s Fire is the same thing that happens in a fluorescent tube- essentially a continuous spark, glowing blue because of the particular combination of air molecules. It may also take on a purple hue.

St. Elmo’s Fire is very difficult to find accurate images or videos of. Many videos exist that claim to be St. Elmo’s Fire but are actually just static discharge (a frequent occurrence around airplanes in the midst of storms). An easy way to tell the difference is that St. Elmo’s Fire does not look like lightning- instead it emits a steady glow.

credit: meteoros.de

Ball lightning- The most mysterious type of “lightning”, there is some dispute among scientists as to whether ball lightning actually exists. Arc faults along power lines (which appear as large, impossibly bright balls of light) and photographic anomalies are both to blame.  Below is a video claiming to show ball lightning, and it actually matches pretty closely the most common descriptions of ball lightning, but whether it actually is is anyone’s guess.

-Staying safe during a thunderstorm

• Lightning regularly strikes water, so never go swimming or boating during a storm. If you are in the water when a storm begins, get out of the water as fast as you can.

• Lightning strikes will follow anything that conducts electricity, so stay off your landline phone during a storm and turn off/unplug your computers. If lightning strikes your house, even the most powerful of surge protectors will have a hard time protecting your equipment. (Radio waves do not conduct electricity, so as long as your cell phone is not plugged in to an outlet and you are not standing outside during the storm with the metal device held to your face, it is safe to use it. They do not inexplicably “attract” lightning more than any other object with metal in it).

• Lightning does in fact strike twice (the Empire State building is struck 20-25 times a year), so don’t rely on old adages for your safety information.

• If you are caught in a thunderstorm and cannot get inside to safety, crouch low to the ground but do not lay flat. Try to keep as much of your body from touching the ground as possible, because you are in more danger of being injured by currents traveling across the ground after a lightning strike than of being stricken directly by a bolt.

• A flash-to-bang (seeing lightning to hearing thunder) ratio of 5 seconds equals one mile of distance from the lightning. Ten seconds equals 2 miles, etc.

 -Lightning in Mythology

One has only to view an electrical storm themselves to understand why so many people have associated lightning and thunder with deity. A few popular myths and legends about lightning:

• Zeus (Jupiter to the Romans) is the planetary god of thunder, and his primary weapon is the thunderbolt (given to him by the Cyclops).

credit: History King

• The Thunderbird common to North American indigenous cultures is said to create thunder by the beating of its wings, and lightning is made by glowing snakes that it carries or directly from its eyes.

credit: ~elderblossom

• Thor is the Norse hammer-wielding god of thunder.

 

credit: fornsed.tumblr

Share your $0.02! Have you had any personal encounters with lightning? Have you or anyone you know been struck by lightning, or have you seen lightning phenomena you couldn’t explain? Share your experiences below!