The most lightning-struck place on Earth - Graeme Anderson

570,659 views ・ 2016-01-28

TED-Ed


Please double-click on the English subtitles below to play the video.

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The epic poem "La Dragontea"
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describes how English explorer Sir Francis Drake
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sailed across the Gulf of Venezuela in 1595.
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He was aiming for the nearby Lake Maracaibo,
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home to a colony of Spanish settlers he planned to overthrow.
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But as Drake moved towards the mouth of the lake under cover of darkness,
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his plot was suddenly and magnificently foiled.
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Huge flashes of lightning illuminated the landscape,
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exposing the fleet as if it were daytime,
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which warned the Spanish about his approach.
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Lake Maracaibo is the stormiest place on the planet.
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The massive body of water at over 13,000 square kilometers
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is a place of almost perpetual storming.
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Thunderstorms rage above it for up to 200 days of the year,
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each earsplitting event lasting for several hours.
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Like everywhere else on Earth,
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lightning at Lake Maracaibo is the result of opposing electrical charges
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that steadily build up inside storm clouds.
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Once there's a large enough difference between charges either within the cloud
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or between the clouds and the Earth below,
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it forms a spark that becomes a lightning bolt.
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Lightning strikes the earth about 350 million times per year,
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averaging out to eleven strikes a second.
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We know that thanks to satellites up in space and sensors on the ground.
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We can also measure the Earth's lightning density,
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which is the frequency with which lightning flashes in a square kilometer.
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Knowing where lightning strikes and how often
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reveals the most lightning-rich places on Earth.
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In the polar regions,
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there may only be one strike per several square kilometers each year.
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Meanwhile, lightning density at the equator
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averages out to tens of flashes per square kilometer
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on account of the sun providing more heat to drive storms.
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Yet nowhere can quite compare with Lake Maracaibo,
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where lightning strikes an average 250 times per square kilometer,
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giving it the highest lightning density of any place on Earth.
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A number of factors converge to create the lake's seemingly everlasting storms.
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Firstly, Lake Maracaibo lies just ten degrees north of the Equator,
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so there's a wealth of solar energy available to fuel the storms.
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Thunderstorms also require a supply of water vapor to feed on,
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and having the warm waters of the Caribbean so close by
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provides an endless supply.
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Finally, the lake's southern and western edges
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are bordered by two massive mountain ranges,
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and as cool winds surge down these slopes,
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they force up warm air,
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destabilizing the atmosphere and causing storm clouds to form.
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Together, these ingredients combine
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to give rise to the most awe-inspiring thunderstorms on the planet,
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a true sight to behold.
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Centuries ago, Sir Francis Drake may have cursed the lake's intense illumination,
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but today, sailors actually embrace this phenomenon.
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They call it the Maracaibo Beacon,
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and use it as a natural lighthouse to illuminate their path across the seas.
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