11:32 am - Monday May 28, 2012

Lightning

Lightning is an atmospheric electrostatic discharge (spark) accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms. From this discharge of atmospheric electricity, a leader of a bolt of lightning can travel at speeds of 220,000 km/h (140,000 mph), and can reach temperatures approaching 30,000 °C (54,000 °F), hot enough to fuse silica sand into glass channels known as fulgurites, which are normally hollow and can extend some distance into the ground. There are some 16 million lightning storms in the world every year. Lightning causes ionisation in the air through which it travels, leading to the formation of nitric oxide and ultimately, nitric acid, of benefit to plant life below.

Lightning Facts

A typical lightning flash lasts about a quarter of a second and consists of 3 or 4 individual discharges called strokes. Each stroke lasts a few ten thousandths of a second, although the visual appearance is longer. The “flicker” sometimes observed in lightning is due to seeing the actual strokes making up the flash.

Lightning Causes
Lightning is produced in thunderstorms when liquid and ice particles above the freezing level collide, and build up large electrical fields in the clouds. Once these electric fields become large enough, a giant “spark” occurs between them (or between them and the ground) like static electricity, reducing the charge separation. The lightning spark can occur between clouds, between the cloud and air, or between the cloud and ground.

Lightning Types

There are a variety of different forms of lightning. Also, observers see lightning differently depending on where they are situated. Major forms of lightning include forked lightning, streak lightning, ribbon lightning, and chain lightning. There are also rare forms of lightning such as ball lightning, red sprites, blue jets, and elves that have been documented.

  • Forked lightning is lightning in which visible branches are present.
  • Streak lightning is a bolt that appears to be a single arc shaped line.
  • Ribbon lightning is viewed as parallel streaks of light. It is caused when winds separate the strokes of the bolt.
  • Chain lightning (also called Bead lightning) is characterized by a bolt that breaks into dotted lines as it fades.
  • Ball lightning’s appearance is that of a fiery glowing ball (usually in red, yellow, or orange) which floats several feet above the ground. It can be as big as a grapefruit in size. It has also been reported to have been floating within houses and barns. It is unknown why ball lightning occurs and what it is made of.
  • Red sprites are characterized as a dim, reddish-colored burst. They only last for a couple thousandth of a second and can be numerous kilometers wide. They appear suddenly, most likely more than one at a time, and rise up to 90 kilometers above the cloud layer.
  • Blue jets are cone-shaped bursts that spring forth from the center of a thunderstorm at speeds up to six thousand kilometers per hour. The rise up to 50 kilometers above the cloud tops and are brighter than red sprites.
  • Elves are bursts of light shaped like a doughnut or saucer. They are about four hundred kilometers wide and occur one hundred kilometers above the cloud tops. They last for less than one thousandth of a second and are theorized to be green in

Lightning Videos & Images

Here you can find latest video & images of famous tornadoes.

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