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*
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This is the most powerful electrical
force on Earth.
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Even hotter than the sun.
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(THUNDER CRACKS)
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For generations it was a mystery.
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Now the latest camera technology
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reveals its incredible secrets.
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Lightning - violence from the skies
of our raging planet.
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Around the world,
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lightning strikes more than
eight million times every day -
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a hundred times a second.
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A bolt of lightning superheats
the surrounding air,
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causing it to rapidly expand
and explode.
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The shockwave
creates a clap of thunder.
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(THUNDER BOOMS)
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Most lightning
never touches the ground.
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It discharges inside thunder clouds.
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But when it does strike,
it can do so anywhere on Earth,
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delivering a trillion watts
of electricity,
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enough energy to power
an entire city.
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Running across the centre of Florida
is America's lightning hot spot,
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known as Lightning Alley.
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Every year there are over 50 strikes
per square mile,
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and every year, people get hit.
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On a September evening in 1999,
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fisherman Dave Grillmeier had just
cast his line into the lake.
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Without warning,
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a bolt of lightning streaked down
from the cloud above him
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with shocking consequences.
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The rod, as you see here,
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what's left of it,
was about a 7ft rod.
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It was obviously so hot that it
burnt the epoxy away, evaporated it,
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and left nothing but the carbon
fibres at the end of the rod.
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It wasn't just the rod
that was damaged.
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Dave suffered multiple burns.
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But it was the condition
of his clothes
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that revealed the true power
of the strike.
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The zipper was all gone.
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And I, several months later,
I asked the paramedic,
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'Well, was there anything
stuck in me?'
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And he goes, 'Your zipper was
almost burned onto your abdomen -
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that's how hot it got.'
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This is what's left.
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This is where my beeper was at,
on my side.
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Doesn't look too bad there
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compared to what the beeper
looked like when I got it back.
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Dave thought his boots
were untouched
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until he saw strange pinholes
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where the lightning
had finally left his body.
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I guess the electricity
passed through my body
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to the bottom of the shoe,
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jumped over the heel
and back to the ground.
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Dave was one of the lucky ones.
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One in every ten lightning
strike victims dies instantly.
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Across North America,
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more people are killed by lightning
than by tornadoes or hurricanes.
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But there is a place on Earth
that's even more dangerous.
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(THUNDER CRACKS)
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The heart of equatorial Africa.
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Here there are more lightning strikes
than anywhere else on Earth.
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Dr Earle Williams
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of the Massachusetts
Institute of Technology
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is a world authority on lightning.
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Using data from NASA satellites,
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he calculates that lightning strikes
the Congo basin
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more than twice as many times
as Florida.
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In some places there are over 300
strikes per square mile every year.
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But lightning in this part of
the world has rarely been studied.
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Thanks very much.
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So today, Earle is at the border
between Zambia
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and the Democratic Republic of Congo
to witness the lightning for himself.
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As darkness falls,
the thunderstorms begin.
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(THUNDER BOOMS)
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There has been much evidence
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that this IS the most electrically
active place on the planet.
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To be here and see it
from the ground
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and witness the high rates
of lightning is very exciting.
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Some strikes can't be seen
with the naked eye,
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so one way to count them
is by using an optical sensor
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that beeps every time
there's a flash.
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(BEEPING)
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An average storm produces
around two strikes a minute.
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Here, Earle measures
more than 60 a minute.
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(BEEPING)
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The storms here are definitely
living up to expectations.
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They're producing lightning at rates
which are extraordinarily high.
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This is really the best place
to study lightning on Earth.
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These are the perfect conditions
for large electrical storms.
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*
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As the Earth is heated by the sun,
it produces lots of warm, moist air.
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Warm air rises.
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As it gains height,
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the moisture cools and condenses
to form clouds.
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These clouds grow and merge
into larger ones,
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rising all the time.
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Some of the water drops
become too heavy
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for the updraft of air to lift.
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They fall as rain.
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Some are lifted
by powerful air currents,
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high into the cold upper regions,
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where they freeze into tiny crystals
of ice.
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As the cloud hits the base
of the stratosphere,
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it spreads out sideways
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to form the anvil shape
typical of thunder clouds.
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Dr Earle Williams of the
Massachusetts Institute of Technology
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studies these clouds.
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The clouds that make lightning
are the largest in the atmosphere.
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A big active cumulonimbus cloud
is about as wide as it is deep,
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and they generate long anvils,
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which extend horizontally
in the prevailing wind, aloft.
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Some ice crystals build in size
to form small hailstones.
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Scientists believe
that as these hailstones
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fall back through the rising
ice crystals,
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millions of tiny collisions occur.
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These collisions
build up an electric charge
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which is stored in the cloud
like a battery.
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A cloud is very much like a battery,
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but a battery with
a much higher voltage
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than your typical flashlight
battery.
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Not 1.5 volts,
but 100 million volts.
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00:08:32,760 --> 00:08:34,760
But what scientists don't know
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is exactly how this electric charge
generates lightning.
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What remains a major
meteorological mystery
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is how it is
that ice particle collisions
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result in the generation
of lightning.
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We're very much in the middle ages
on that problem.
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It's extremely difficult
to study lightning,
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since each strike lasts
just a fraction of a second.
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One of the best ways is to freeze
the action using a camera.
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David Stillings is a photographer
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who patrols Lightning Alley
in pursuit of electric storms.
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For the last 30 years
he's been obsessed with lightning.
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I'd put my last few cents
in my gas tank
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if it meant I could go chase
a storm.
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His success rate
is less than one per cent,
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but when he does capture lightning,
the results are spectacular.
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(THUNDER CRACKS)
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Back in 1976,
this was the first one.
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And when it popped out of that cloud
right there
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with that blue sky in there
and the purple cloud - oh!
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And from that point on,
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lightning was everything
I wanted to photograph.
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This particular one, it's got
so many bolts of lightning in it,
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and they all happened
at the same time.
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This is in 2004.
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The shutter couldn't have been open
more than one second.
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00:10:10,520 --> 00:10:13,040
A purple sky, gold sunset -
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all the neat stuff
that I love to see out there.
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And it all came together in one
photograph! That's cool. (LAUGHS)
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00:10:21,280 --> 00:10:24,720
But before David can even begin
to photograph lightning,
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he has to find it.
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Those two domes there
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might be getting high enough
to produce lightning.
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And the sun is breaking through
and it's going to heat it up.
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The humidity's going to start.
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This is cool. This is...
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This has the potential
of being good stuff.
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David has found a thunderstorm
that will produce lightning.
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Now the challenge is to point
his camera in the right direction.
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And I hope it's a big one
right there.
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An average storm here
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will produce a couple of lightning
flashes every minute,
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but it's impossible to predict
where they will strike next.
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(THUNDER RUMBLES)
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Whoa! Whoa!
I'm in the wrong spot again.
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Jeez!
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Whoa! Whoa!
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Be later, please!
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Man, listen to this thunder.
Listen to this.
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Listen to that.
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There's another one right there.
Oh, man!
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This is a dangerous occupation.
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Cos I got to... Oh! Oh, man!
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Lightning can strike anything
and anyone
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up to 40km away from a cloud.
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(CAMERA CLICKS)
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(THUNDER CRACKS)
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(DAVID YELLS DISTANTLY)
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David prefers to use
a traditional film camera,
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00:12:12,320 --> 00:12:15,160
so he never knows
whether he's got the shot
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00:12:15,160 --> 00:12:17,480
till he gets
the processed photos back.
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00:12:17,480 --> 00:12:20,680
Please tell me there's something
on there.
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00:12:22,720 --> 00:12:24,200
Roll after roll after...
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Oh, look, I got a streak of
lightning right there. Nah.
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Occasionally,
David's patience pays off,
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and he manages to capture
the elusive phenomenon on film.
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Oh, look! The channel! Yay!
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Oh, man, it's...
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Oh, man, is that cool?!
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This is neat, man. I... Oh!
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(THUNDER CRACKS)
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The bottom line is, yeah,
this is my addiction.
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00:12:49,560 --> 00:12:52,400
But if you have to be addicted to
something, look.
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A picture of a lightning strike
frozen in time
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can be a work of art.
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00:13:00,480 --> 00:13:03,120
But photography
is also extremely valuable
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00:13:03,120 --> 00:13:04,720
for scientific analysis.
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00:13:05,880 --> 00:13:07,360
(THUNDER CRACKS)
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00:13:07,360 --> 00:13:09,400
When observed with the naked eye,
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00:13:09,400 --> 00:13:13,400
lightning appears to travel from
the clouds directly to the ground.
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But recent advances
in video camera technology
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00:13:19,120 --> 00:13:23,320
reveal that the anatomy of lightning
is much more complex.
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00:13:24,880 --> 00:13:28,360
This is the US Air Force
Atmospheric Research Center
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00:13:28,360 --> 00:13:30,640
in Colorado Springs.
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00:13:30,640 --> 00:13:32,280
Here Dr Geoff McHarg
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00:13:32,280 --> 00:13:36,200
is using a super slow motion camera
to capture lightning.
207
00:13:37,440 --> 00:13:41,200
To do this, he needs
split-second timing.
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00:13:41,200 --> 00:13:43,040
Oh, darn it.
209
00:13:43,040 --> 00:13:45,800
It's a lot like fishing.
You have to get lucky
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00:13:45,800 --> 00:13:48,960
and get the lightning bolt
inside your field of view.
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00:13:48,960 --> 00:13:50,520
Success is rare,
212
00:13:50,520 --> 00:13:53,760
but two years ago,
Geoff hit the jackpot.
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00:13:58,560 --> 00:14:01,480
I was simply
watching the lightning get closer,
214
00:14:01,480 --> 00:14:03,080
and I kept recording it.
215
00:14:03,080 --> 00:14:06,640
And I didn't know what I had
until I went back and reviewed it.
216
00:14:06,640 --> 00:14:08,640
For the first time ever,
217
00:14:08,640 --> 00:14:11,440
Geoff had recorded
the birth of a lightning bolt
218
00:14:11,440 --> 00:14:13,080
in super slow motion.
219
00:14:20,120 --> 00:14:21,600
When played back,
220
00:14:21,600 --> 00:14:24,480
it shows a flash of light
dart out of a cloud
221
00:14:24,480 --> 00:14:28,280
and zigzag downward in roughly
50-yard segments.
222
00:14:31,400 --> 00:14:35,000
This first stage of lightning
is called a stepped leader.
223
00:14:36,240 --> 00:14:38,960
You can see the stepped leader
coming down here,
224
00:14:38,960 --> 00:14:41,640
looking for ground,
going back and forth.
225
00:14:41,640 --> 00:14:44,280
You can see the torturous channel
it is taking
226
00:14:44,280 --> 00:14:46,000
as it divides back and forth.
227
00:14:48,320 --> 00:14:51,080
As this stepped leader
gets close to the earth,
228
00:14:51,080 --> 00:14:54,360
it has an extraordinary effect
on objects on the ground.
229
00:14:58,360 --> 00:15:00,880
They respond
to the strong electric field
230
00:15:00,880 --> 00:15:03,040
by growing positive streamers.
231
00:15:05,440 --> 00:15:07,240
These reach up anywhere
232
00:15:07,240 --> 00:15:10,440
between one and a few hundred metres
above the ground,
233
00:15:10,440 --> 00:15:12,760
as seen in these rare photographs.
234
00:15:14,440 --> 00:15:18,320
Finally, when a stepped leader
and a positive streamer meet,
235
00:15:18,320 --> 00:15:20,640
the electric charge
can drain to earth,
236
00:15:20,640 --> 00:15:25,600
resulting in the blinding flash
of light we call lightning.
237
00:15:28,960 --> 00:15:31,000
The entire field of view lights up.
238
00:15:31,000 --> 00:15:33,560
That's the main part
of the lightning strike
239
00:15:33,560 --> 00:15:35,200
that your eye would catch.
240
00:15:36,200 --> 00:15:38,760
(THUNDER CRACKS)
241
00:15:40,000 --> 00:15:43,240
The new generation of cameras
has enabled scientists
242
00:15:43,240 --> 00:15:47,440
to record a strike that lasts
just a fraction of a second.
243
00:15:47,440 --> 00:15:49,240
(THUNDER CRACKS)
244
00:15:50,480 --> 00:15:53,560
They then play it back
over 200 times slower
245
00:15:53,560 --> 00:15:55,160
to analyse its details.
246
00:15:57,360 --> 00:16:00,960
These super slow motion images
show the stepped leader
247
00:16:00,960 --> 00:16:03,280
making a connection with the ground.
248
00:16:05,240 --> 00:16:08,560
The entire charge then drains
from the cloud above,
249
00:16:08,560 --> 00:16:10,760
seen as a series of pulses.
250
00:16:14,280 --> 00:16:16,560
Scientists are now just beginning
251
00:16:16,560 --> 00:16:19,840
to unravel the mysteries
of lightning.
252
00:16:24,960 --> 00:16:28,160
New research has revealed
that heat and humidity
253
00:16:28,160 --> 00:16:31,960
can have an effect on the frequency
of lightning storms.
254
00:16:32,960 --> 00:16:35,520
(THUNDER CRACKS)
255
00:16:38,000 --> 00:16:42,000
*
256
00:16:49,320 --> 00:16:53,760
Tampa, Florida, is the lightning
capital of the United States,
257
00:16:53,760 --> 00:16:56,160
with more lightning
than anywhere else.
258
00:17:00,640 --> 00:17:03,880
Scott Steiger from State University
of New York
259
00:17:03,880 --> 00:17:06,160
believes the city attracts lightning
260
00:17:06,160 --> 00:17:08,760
because Tampa
is an urban heat island.
261
00:17:11,280 --> 00:17:13,720
An urban heat island
is caused by the fact
262
00:17:13,720 --> 00:17:17,280
that a city area has a lot more
impervious surfaces
263
00:17:17,280 --> 00:17:19,160
of asphalt and concrete
264
00:17:19,160 --> 00:17:21,920
that absorbs a lot of the
sun's solar radiation.
265
00:17:21,920 --> 00:17:26,200
That energy gets re-emitted
and warms the air in the city.
266
00:17:26,200 --> 00:17:29,320
A city can be as much as
15 degrees warmer
267
00:17:29,320 --> 00:17:31,600
than the surrounding rural areas.
268
00:17:33,600 --> 00:17:35,240
As the warm air rises,
269
00:17:35,240 --> 00:17:39,640
it creates strong upward convection
in the atmosphere over the city.
270
00:17:41,120 --> 00:17:44,240
This urban heat island can cause
more thunderstorms
271
00:17:44,240 --> 00:17:47,200
as it develops a convergence zone
over the city,
272
00:17:47,200 --> 00:17:50,720
which helps to lift the air
and initiate more thunderstorms.
273
00:17:53,280 --> 00:17:57,200
The creation of thunderstorms
means lightning is inevitable.
274
00:17:59,080 --> 00:18:01,600
Especially cities in warm,
humid climates,
275
00:18:01,600 --> 00:18:04,360
like Tampa Bay, Florida,
and Houston, Texas,
276
00:18:04,360 --> 00:18:07,720
are very capable of producing
more thunderstorms
277
00:18:07,720 --> 00:18:11,040
and more lightning, which is
more dangerous to the public.
278
00:18:12,200 --> 00:18:15,360
Scientific research
has recently produced evidence
279
00:18:15,360 --> 00:18:18,360
that lightning doesn't just
come down from above.
280
00:18:20,400 --> 00:18:23,200
It also streaks up
high into the sky.
281
00:18:29,440 --> 00:18:30,920
Here in Rapid City,
282
00:18:30,920 --> 00:18:34,760
scientist Tom Warner
has been using high speed photography
283
00:18:34,760 --> 00:18:38,080
to uncover a previously hidden world
of lightning.
284
00:18:39,080 --> 00:18:42,600
We're seeing things in such a way
that we've never seen before.
285
00:18:43,640 --> 00:18:45,400
Using a battery of cameras,
286
00:18:45,400 --> 00:18:48,240
he's managed to capture
some astonishing images
287
00:18:48,240 --> 00:18:52,160
which show lightning travelling
not from cloud to ground
288
00:18:52,160 --> 00:18:54,760
but shooting upwards.
289
00:19:05,840 --> 00:19:08,160
This extraordinary form of lightning
290
00:19:08,160 --> 00:19:10,800
has been known about since the 1930s,
291
00:19:10,800 --> 00:19:14,240
but these pictures have finally
confirmed its existence.
292
00:19:19,280 --> 00:19:21,360
This is the first time that mankind
293
00:19:21,360 --> 00:19:24,000
has seen upward lightning
in such detail
294
00:19:24,000 --> 00:19:25,720
as we're seeing right now.
295
00:19:25,720 --> 00:19:29,280
Our understanding of physics
relating to these upward flashes
296
00:19:29,280 --> 00:19:30,880
is increasing immensely.
297
00:19:30,880 --> 00:19:33,640
Tom has observed
that upward lightning
298
00:19:33,640 --> 00:19:37,880
is triggered by a nearby
cloud-to-ground lightning strike.
299
00:19:39,760 --> 00:19:44,040
In this image a lightning strike
produces a bright flash of light.
300
00:19:45,360 --> 00:19:49,600
In under a second, it initiates
the formation of upward leaders
301
00:19:49,600 --> 00:19:51,440
from two radio masts.
302
00:19:53,960 --> 00:19:56,960
Why this happens is still a mystery,
303
00:19:56,960 --> 00:19:59,600
but Tom's theory is that
the lightning strike
304
00:19:59,600 --> 00:20:02,200
causes large amounts
of electric charge
305
00:20:02,200 --> 00:20:05,360
to build up around the top
of a tall structure,
306
00:20:05,360 --> 00:20:09,440
and this charge leaps up and connects
with a cloud above.
307
00:20:13,120 --> 00:20:16,160
You'll see a delay between
when the flash takes place
308
00:20:16,160 --> 00:20:20,320
and then the leader is shot up from
the tower tip and goes upward.
309
00:20:21,760 --> 00:20:24,880
The images Tom has filmed
over the last few years
310
00:20:24,880 --> 00:20:28,000
have astounded the world
of lightning science.
311
00:21:48,480 --> 00:21:50,560
This mysterious lightning
312
00:21:50,560 --> 00:21:54,840
would never have been seen without
state-of-the-art technology.
313
00:21:54,840 --> 00:21:56,600
(THUNDER RUMBLES)
314
00:21:56,600 --> 00:22:00,480
But to see one of the greatest
lightning displays on the planet,
315
00:22:00,480 --> 00:22:03,360
the only equipment you need
is your eyes.
316
00:22:07,840 --> 00:22:10,720
Here on Venezuela's Lake Maracaibo,
317
00:22:10,720 --> 00:22:14,000
a team of scientists
from the University of Zulia
318
00:22:14,000 --> 00:22:15,600
are setting out in search of
319
00:22:15,600 --> 00:22:18,320
the region's legendary
Catatumbo lightning.
320
00:22:24,400 --> 00:22:28,360
Unusual conditions in this area
create a unique kind of lightning.
321
00:22:33,120 --> 00:22:36,600
Methane gas bubbles up
from rotting vegetation
322
00:22:36,600 --> 00:22:38,400
in the swamps and rivers.
323
00:22:40,800 --> 00:22:45,920
And Lake Maracaibo's oilfields
also produce methane as a by-product.
324
00:22:47,280 --> 00:22:50,840
It all accumulates in the atmosphere
above the marshes.
325
00:22:58,960 --> 00:23:00,440
As night falls,
326
00:23:00,440 --> 00:23:03,720
the scientists
are hoping for an electrical storm
327
00:23:03,720 --> 00:23:06,880
so they can study the extraordinary
effects of the gas.
328
00:23:10,360 --> 00:23:12,040
Methane is lighter than air.
329
00:23:13,080 --> 00:23:16,880
As it rises up into the clouds,
it feeds the storm,
330
00:23:16,880 --> 00:23:20,000
creating brighter,
much more colourful lightning.
331
00:23:29,280 --> 00:23:32,960
But lead scientist
Professor Angel Munoz and his team
332
00:23:32,960 --> 00:23:36,840
think there may be more to Catatumbo
lightning than meets the eye.
333
00:23:54,880 --> 00:23:57,800
Catatumbo lightning
leaps from cloud to cloud,
334
00:23:57,800 --> 00:24:01,240
and is much more powerful
than cloud-to-ground lightning.
335
00:24:01,240 --> 00:24:03,560
(THUNDER RUMBLES)
336
00:24:03,560 --> 00:24:06,840
On average, it can be seen 200 nights
of the year
337
00:24:06,840 --> 00:24:09,120
for up to ten hours a night.
338
00:24:30,360 --> 00:24:36,120
This display is so colossal,
it's visible 160km out to sea.
339
00:24:37,720 --> 00:24:41,040
For centuries,
sailors used it for navigation.
340
00:24:42,280 --> 00:24:44,840
It was known
as the Maracaibo Lighthouse.
341
00:24:48,600 --> 00:24:52,480
A lightning storm can be spectacular
from a distance,
342
00:24:52,480 --> 00:24:55,800
but up close,
lightning can be deadly.
343
00:25:03,960 --> 00:25:05,440
During a thunderstorm,
344
00:25:05,440 --> 00:25:09,360
the most dangerous place to be
is in a wide open space...
345
00:25:11,120 --> 00:25:14,400
...including any
large expanse of water.
346
00:25:16,160 --> 00:25:19,840
And it's true that sheltering
under a tree is a bad idea.
347
00:25:20,840 --> 00:25:24,840
Lightning can turn tree sap
into superheated steam,
348
00:25:24,840 --> 00:25:29,480
making the tree explode in a shower
of potentially deadly splinters.
349
00:25:36,040 --> 00:25:39,920
Lightning can also travel down
telephone lines.
350
00:25:51,080 --> 00:25:55,160
There's a very scary warning sign
that you're in danger.
351
00:25:58,320 --> 00:26:01,960
If your hair stands up, you've just
become a positive streamer.
352
00:26:01,960 --> 00:26:03,840
And coming down from that cloud
353
00:26:03,840 --> 00:26:06,880
is a negative leader that,
if you don't do something,
354
00:26:06,880 --> 00:26:10,240
when they connect, you've just
become a bolt of lightning.
355
00:26:12,400 --> 00:26:15,600
If this happens to you,
the best thing to do
356
00:26:15,600 --> 00:26:18,520
is to quickly crouch down
on the balls of your feet.
357
00:26:20,760 --> 00:26:22,600
(LOUD CRACK)
358
00:26:24,520 --> 00:26:28,320
Student Carolynn Nath had no warning
she was in danger.
359
00:26:30,000 --> 00:26:31,880
She was making her way to class
360
00:26:31,880 --> 00:26:36,280
at the University of South Florida
in Tampa when lightning struck.
361
00:26:37,360 --> 00:26:39,240
(THUNDER CRACKS)
362
00:26:39,240 --> 00:26:41,720
I heard a loud, loud crack
of thunder,
363
00:26:41,720 --> 00:26:45,280
and within a second, I saw a light.
364
00:26:45,280 --> 00:26:48,840
Basically, the corridor
in front of me of palm trees
365
00:26:48,840 --> 00:26:50,640
was an overexposed picture.
366
00:26:50,640 --> 00:26:54,320
And I felt the electricity start
going through my entire body.
367
00:26:56,480 --> 00:27:00,160
I could feel it, every ounce,
every inch of my body.
368
00:27:00,160 --> 00:27:03,680
My muscles expanded,
they contracted very tightly.
369
00:27:03,680 --> 00:27:06,080
And every nerve, it just...
370
00:27:06,080 --> 00:27:09,480
I could feel that pressure
going through my entire body.
371
00:27:09,480 --> 00:27:12,440
The after-effects were devastating.
372
00:27:12,440 --> 00:27:16,480
Everything was completely swollen.
My skin was lobster red.
373
00:27:16,480 --> 00:27:19,760
It was basically like I had a very,
very severe sunburn.
374
00:27:19,760 --> 00:27:24,360
So, afterwards, everything...
all my skin peeled off.
375
00:27:24,360 --> 00:27:27,400
(THUNDER CRACKS)
376
00:27:28,400 --> 00:27:32,200
A lightning flash
contains up to 200,000 amps...
377
00:27:33,280 --> 00:27:37,880
...but it takes just one-tenth of
an amp to kill a human being.
378
00:27:37,880 --> 00:27:39,680
(SIREN WAILS)
379
00:27:39,680 --> 00:27:44,920
So how do victims survive a lightning
strike and live to tell the tale?
380
00:27:47,080 --> 00:27:51,760
Doctors at the University of Illinois
have been trying to find the answer.
381
00:27:53,880 --> 00:27:55,680
Professor Mary Ann Cooper
382
00:27:55,680 --> 00:27:59,280
is an expert on what happens
when lightning strikes.
383
00:28:00,680 --> 00:28:02,760
When lightning attaches to a person,
384
00:28:02,760 --> 00:28:06,680
the vast majority of the energy goes
around the outside of the person
385
00:28:06,680 --> 00:28:08,240
rather than through them.
386
00:28:10,960 --> 00:28:13,280
Instead of striking vital organs,
387
00:28:13,280 --> 00:28:18,560
the charge flows through the moisture
on the skin and down to the ground.
388
00:28:18,560 --> 00:28:22,360
It can leave behind scars
called Lichtenberg marks.
389
00:28:24,720 --> 00:28:26,600
As it's going around the outside,
390
00:28:26,600 --> 00:28:30,920
it may turn the rainwater or sweat
the person has on them into steam.
391
00:28:30,920 --> 00:28:34,200
Sometimes, the build-up of steam
in clothing or shoes
392
00:28:34,200 --> 00:28:36,560
can have explosive consequences.
393
00:28:40,560 --> 00:28:43,360
You may have heard about people
in explosions
394
00:28:43,360 --> 00:28:44,960
blown out of their shoes -
395
00:28:44,960 --> 00:28:48,120
that's what we see sometimes
with lightning as well.
396
00:28:48,120 --> 00:28:51,440
Because that sweat or the water
expands tremendously
397
00:28:51,440 --> 00:28:54,920
so that we actually see more damage
to the inside of footwear
398
00:28:54,920 --> 00:28:58,360
and sometimes to clothing
than we see to the outside of it.
399
00:29:02,640 --> 00:29:07,200
A lightning strike can cause cardiac
arrest, but this is rare.
400
00:29:09,280 --> 00:29:13,040
MARY ANN: The vast majority of
people survive lightning injury,
401
00:29:13,040 --> 00:29:15,680
although they may have
permanent problems,
402
00:29:15,680 --> 00:29:18,120
including damage to
the nervous system.
403
00:29:18,120 --> 00:29:20,920
One survivor, Pam Cooper,
404
00:29:20,920 --> 00:29:23,800
is still suffering from
the damaging power of a strike.
405
00:29:24,800 --> 00:29:29,840
I was just a mom sitting
on the beach with my book,
406
00:29:29,840 --> 00:29:33,360
minding my own business,
doing nothing extraordinary,
407
00:29:33,360 --> 00:29:38,240
and my life was changed forever
by lightning.
408
00:29:38,240 --> 00:29:39,800
(THUNDER CRACKS)
409
00:29:40,800 --> 00:29:44,480
I don't remember the actual event
of being struck.
410
00:29:44,480 --> 00:29:48,520
It's through my friends and family
that I know second-hand
411
00:29:48,520 --> 00:29:50,240
what exactly happened to me.
412
00:29:50,240 --> 00:29:55,760
That day, Destin Beach in Florida
was hot and sunny.
413
00:29:57,120 --> 00:30:02,360
My family says that they heard
a large clap of thunder, lightning.
414
00:30:03,400 --> 00:30:07,120
Everyone else was starting to scurry
and pick up their belongings
415
00:30:07,120 --> 00:30:09,840
because of the lightning strike
being so close.
416
00:30:09,840 --> 00:30:12,120
I was sitting with my feet
in the sand,
417
00:30:12,120 --> 00:30:16,400
and the lightning struck the sand
and then came up through my feet.
418
00:30:17,560 --> 00:30:19,320
(DISTANT SIREN)
419
00:30:19,320 --> 00:30:22,480
Pam was rushed to the hospital
with extensive burns.
420
00:30:24,640 --> 00:30:28,360
Five years later, she still suffers
from mobility problems
421
00:30:28,360 --> 00:30:30,600
and short-term memory loss.
422
00:30:33,280 --> 00:30:37,560
Being struck by lightning is very
similar to a computer crashing,
423
00:30:37,560 --> 00:30:42,760
because, on the outside,
I look fine.
424
00:30:42,760 --> 00:30:46,680
But on the inside, my circuitry's
all messed up.
425
00:30:47,680 --> 00:30:50,120
Pam's experience
could happen to anyone,
426
00:30:50,120 --> 00:30:53,560
so it's vital to know exactly
what to do
427
00:30:53,560 --> 00:30:56,240
to protect yourself
from a lightning strike.
428
00:31:03,000 --> 00:31:07,000
*
429
00:31:11,840 --> 00:31:16,760
When a thunderstorm forms,
people's lives can be at risk.
430
00:31:17,920 --> 00:31:20,800
We tell people, 'When thunder roars,
go indoors.'
431
00:31:20,800 --> 00:31:23,080
What we mean is
'Seek a safer shelter.'
432
00:31:24,440 --> 00:31:26,320
If you're ever in a thunderstorm,
433
00:31:26,320 --> 00:31:29,320
one of the safest places to be
is in a closed vehicle.
434
00:31:32,400 --> 00:31:36,280
Many people believe the rubber tyres
on a car will keep them safe,
435
00:31:36,280 --> 00:31:38,000
but that's not true.
436
00:31:40,280 --> 00:31:43,480
It's the car's metal body
that provides protection...
437
00:31:45,720 --> 00:31:48,920
...as this high-voltage
experiment will demonstrate.
438
00:31:50,600 --> 00:31:53,480
A Tesla coil
is the lightning simulator,
439
00:31:53,480 --> 00:31:56,480
an electrical transformer
that discharges
440
00:31:56,480 --> 00:31:59,960
three-quarters of a million volts
of electricity.
441
00:32:05,520 --> 00:32:08,680
Dr Lisa Lazareck
is an electrical engineer
442
00:32:08,680 --> 00:32:11,480
who's willing to sit in a car
underneath the coil
443
00:32:11,480 --> 00:32:14,480
to prove that
its metal body will protect her.
444
00:32:14,480 --> 00:32:18,720
The electrical charge striking
this car is going to conduct
445
00:32:18,720 --> 00:32:21,720
around the outside surface
of the enclosed body,
446
00:32:21,720 --> 00:32:25,720
so I should be fine as long as I
don't touch the metal of the car.
447
00:32:25,720 --> 00:32:28,280
But it's one thing to talk about
the theory,
448
00:32:28,280 --> 00:32:31,040
and it's another thing
to put it into practice.
449
00:32:31,040 --> 00:32:32,680
So I guess I'm ready.
450
00:32:39,520 --> 00:32:43,680
The electrical charge flows around
the metal body of the car
451
00:32:43,680 --> 00:32:46,160
and discharges harmlessly
to the ground.
452
00:32:48,480 --> 00:32:51,680
I'm fine.
The theory has worked as expected.
453
00:32:51,680 --> 00:32:53,400
My feet are slightly tingling,
454
00:32:53,400 --> 00:32:57,000
and, because I was nervous, my hands
are still clamped together.
455
00:32:57,000 --> 00:32:58,960
But other than that, I'm fine.
456
00:33:06,640 --> 00:33:09,680
The experiment has just proved
the rule of physics
457
00:33:09,680 --> 00:33:12,280
that an electrical charge
like lightning
458
00:33:12,280 --> 00:33:17,160
will always travel around the outside
surface of an enclosed metal body.
459
00:33:18,520 --> 00:33:22,800
That's why passengers are unharmed
when a plane is struck by lightning.
460
00:33:26,640 --> 00:33:30,600
This incredibly rare footage of
a plane flying into Sydney Airport
461
00:33:30,600 --> 00:33:32,800
shows a dramatic strike.
462
00:33:38,000 --> 00:33:40,560
No-one on board
even knew they'd been hit.
463
00:33:42,840 --> 00:33:45,080
And this video captures another
464
00:33:45,080 --> 00:33:47,760
as a plane takes off
from an airport in Japan.
465
00:33:50,920 --> 00:33:54,320
Once again, the passengers
had no idea what happened.
466
00:33:57,440 --> 00:34:01,920
On average, every commercial aircraft
is hit once a year.
467
00:34:11,440 --> 00:34:14,560
Besides suffering a direct hit
from a lightning bolt,
468
00:34:14,560 --> 00:34:18,600
the biggest threat to life
is when lightning triggers a fire.
469
00:34:39,320 --> 00:34:41,880
During the summer of 2008,
470
00:34:41,880 --> 00:34:44,720
an unusually high number
of lightning strikes
471
00:34:44,720 --> 00:34:47,680
set large areas of California
on fire.
472
00:34:58,440 --> 00:35:02,680
One single storm unleashed
up to 5,000 strikes...
473
00:35:03,720 --> 00:35:06,960
...igniting more than a thousand
individual fires.
474
00:35:12,960 --> 00:35:16,000
The flames destroyed dozens of homes.
475
00:35:19,440 --> 00:35:21,040
In a lightning-prone area,
476
00:35:21,040 --> 00:35:25,280
living in houses built among trees
carries a high risk.
477
00:35:32,400 --> 00:35:33,920
But though lightning fires
478
00:35:33,920 --> 00:35:36,520
can destroy property
and devastate forests,
479
00:35:36,520 --> 00:35:41,080
they can also have a positive
effect on the landscape.
480
00:35:43,520 --> 00:35:47,640
Nature has evolved a way to work
in harmony with lightning fires,
481
00:35:47,640 --> 00:35:50,400
and even depends on them
to renew life.
482
00:35:53,320 --> 00:35:57,840
Here, in the Australian outback,
such fires are a common occurrence.
483
00:36:00,320 --> 00:36:04,200
Jeffrey Lee is a park ranger
charged with looking after the land.
484
00:36:07,240 --> 00:36:10,200
He welcomes the fires
because they clear the ground
485
00:36:10,200 --> 00:36:14,400
and encourage the regrowth
of edible plants, or bush tucker.
486
00:36:30,080 --> 00:36:31,760
Many plant species
487
00:36:31,760 --> 00:36:35,280
have evolved to colonise the areas
these fires lay bare.
488
00:36:35,280 --> 00:36:40,080
and some seeds actually need fire
to germinate.
489
00:36:40,080 --> 00:36:43,800
Lightning also helps produce
vital plant fertilisers.
490
00:36:45,520 --> 00:36:47,080
(THUNDER CRACKS)
491
00:36:49,960 --> 00:36:55,280
At its peak, the temperature of
a lightning bolt hits 50,000 degrees,
492
00:36:55,280 --> 00:36:57,160
burning the air.
493
00:36:58,200 --> 00:37:03,040
In the heat, nitrogen and oxygen
react together to create nitrates.
494
00:37:04,080 --> 00:37:08,040
These rain to the earth and provide
nutrients for plants.
495
00:37:12,080 --> 00:37:16,640
Scientists have now discovered that
lightning may also be playing a part
496
00:37:16,640 --> 00:37:18,720
high in the Earth's atmosphere.
497
00:37:20,640 --> 00:37:23,960
When these bizarre images
were taken from above the earth,
498
00:37:23,960 --> 00:37:26,960
they took scientists
completely by surprise.
499
00:37:29,520 --> 00:37:31,760
They showed huge bursts of light
500
00:37:31,760 --> 00:37:34,600
flashing over the top
of electric storms.
501
00:37:37,200 --> 00:37:41,400
Called sprites, they were first
photographed in 1989.
502
00:37:43,040 --> 00:37:46,440
Since then, scientific projects
around the world
503
00:37:46,440 --> 00:37:49,400
have joined the hunt
for these elusive phenomena.
504
00:37:56,120 --> 00:38:01,160
In 1997, New Zealand scientist
Professor Richard Dowden
505
00:38:01,160 --> 00:38:04,000
arrived in Australia's
Northern Territory
506
00:38:04,000 --> 00:38:06,160
on a quest for sprites.
507
00:38:09,320 --> 00:38:12,960
Richard wanted to be one of the first
to capture them on camera.
508
00:38:16,400 --> 00:38:19,800
He came here with his scientific team
to Beatrice Hill,
509
00:38:19,800 --> 00:38:23,120
60km east of Darwin.
510
00:38:25,520 --> 00:38:27,160
(THUNDER CRACKS)
511
00:38:27,160 --> 00:38:31,040
This region is home to some of
the biggest thunderstorms on Earth.
512
00:38:33,760 --> 00:38:37,240
But Richard wasn't interested
in regular lightning bolts.
513
00:38:39,160 --> 00:38:43,600
He was chasing sprites, which appear
directly above thunderstorms.
514
00:38:47,000 --> 00:38:49,800
Beatrice Hill was a perfect place
to spot them,
515
00:38:49,800 --> 00:38:53,120
because you need a clear view of
the top of a thundercloud
516
00:38:53,120 --> 00:38:56,080
from a distance of nearly 100km.
517
00:38:58,400 --> 00:39:02,440
Even then, the sprites are hard to
see with the naked eye
518
00:39:02,440 --> 00:39:05,680
because they're only visible
for a few milliseconds.
519
00:39:08,960 --> 00:39:11,720
So Richard made
a special modification
520
00:39:11,720 --> 00:39:13,960
to his standard amateur camera.
521
00:39:15,920 --> 00:39:18,960
The big change was this thing
in front of it,
522
00:39:18,960 --> 00:39:21,880
which is an image intensifier.
523
00:39:21,880 --> 00:39:26,120
These are used by the military
all over the world.
524
00:39:26,120 --> 00:39:29,280
Rather hard to get, the ones
which are very sensitive.
525
00:39:29,280 --> 00:39:34,160
This one here actually came from
Russia, from the Russian military.
526
00:39:35,240 --> 00:39:38,720
Richard and his team waited night
after night,
527
00:39:38,720 --> 00:39:40,800
taking turns manning the camera.
528
00:39:40,800 --> 00:39:44,920
After nearly two weeks,
they finally had a breakthrough.
529
00:39:44,920 --> 00:39:50,760
Well, on the night we got those
sprites, it was really a big thrill.
530
00:39:51,760 --> 00:39:54,240
But we didn't know what was there
531
00:39:54,240 --> 00:39:58,560
until we ran the tapes
back out of the camera.
532
00:40:02,840 --> 00:40:06,520
The tapes reveal these flickering
images of sprites
533
00:40:06,520 --> 00:40:08,680
speeding through the atmosphere
534
00:40:08,680 --> 00:40:11,360
at more than one-tenth
the speed of light.
535
00:40:19,520 --> 00:40:21,320
That was a fantastic thing.
536
00:40:21,320 --> 00:40:24,680
I don't think we got any sleep,
any more sleep that night.
537
00:40:24,680 --> 00:40:30,760
Scientists remain mystified by the
first fleeting sightings of sprites.
538
00:40:33,560 --> 00:40:35,360
But just two years later,
539
00:40:35,360 --> 00:40:39,680
Dr Geoff McHarg of the US Air Force
Atmospheric Research Academy
540
00:40:39,680 --> 00:40:41,800
made another breakthrough.
541
00:40:41,800 --> 00:40:46,320
He managed to record sprites
using an image intensifier
542
00:40:46,320 --> 00:40:49,040
on the front of
his super slow motion camera.
543
00:40:50,360 --> 00:40:54,240
It was probably the most fun I've
actually ever had taking data.
544
00:40:54,240 --> 00:40:55,840
It was just great.
545
00:40:55,840 --> 00:40:57,600
We took data all night long.
546
00:40:57,600 --> 00:41:00,360
We recorded pretty much
every tape that we had.
547
00:41:02,120 --> 00:41:06,320
The tapes revealed an incredible
variety of sprites.
548
00:41:06,320 --> 00:41:09,320
The scientists have since
given them names.
549
00:41:09,320 --> 00:41:12,720
What we're looking at right now
is a jellyfish sprite,
550
00:41:12,720 --> 00:41:16,360
and the first thing you'll see is,
they're very large.
551
00:41:16,360 --> 00:41:21,040
They may be 30 miles tall,
30 miles wide.
552
00:41:21,040 --> 00:41:25,120
Just think about that. That's almost
from Colorado Springs to Denver.
553
00:41:25,120 --> 00:41:29,960
Then there's the extraordinary
carrot sprite.
554
00:41:29,960 --> 00:41:32,320
It physically looks like a carrot,
555
00:41:32,320 --> 00:41:36,800
with the upper part being like
the leaves of a carrot
556
00:41:36,800 --> 00:41:39,160
and the downward tendril
that we call it
557
00:41:39,160 --> 00:41:41,240
going like the stalk of the carrot.
558
00:41:44,440 --> 00:41:48,200
Geoff also captured the 'C'
or column sprite.
559
00:41:50,240 --> 00:41:52,520
Here we have three of them
side-by-side.
560
00:41:52,520 --> 00:41:54,840
And the motion is pretty much
all down,
561
00:41:54,840 --> 00:41:57,240
hence the name 'column'
or 'C' sprite.
562
00:42:00,960 --> 00:42:03,480
Around the world,
as many as ten sprites
563
00:42:03,480 --> 00:42:06,760
could be shooting up from the clouds
every minute.
564
00:42:12,560 --> 00:42:17,480
Scientists now know that sprites are
large-scale electrical discharges
565
00:42:17,480 --> 00:42:19,600
that make the air above them glow
566
00:42:19,600 --> 00:42:22,840
in a similar way to
a fluorescent light bulb.
567
00:42:23,840 --> 00:42:25,840
But it will take a lot more research
568
00:42:25,840 --> 00:42:29,320
before we truly understand
these electrical phenomena.
569
00:42:29,320 --> 00:42:31,480
(THUNDER CRACKS)
570
00:42:36,760 --> 00:42:39,440
Even though the serious study
of lightning
571
00:42:39,440 --> 00:42:41,640
began over two centuries ago,
572
00:42:41,640 --> 00:42:44,320
scientists are still struggling
to work out
573
00:42:44,320 --> 00:42:46,440
what guides lightning's path
574
00:42:46,440 --> 00:42:50,200
or why it chooses to strike
in one place over another.
575
00:42:51,880 --> 00:42:55,160
We've learned a lot about lightning
in a few hundred years,
576
00:42:55,160 --> 00:42:58,080
but there is still a major
meteorological mystery.
577
00:43:00,520 --> 00:43:02,160
What we do know
578
00:43:02,160 --> 00:43:06,080
is that lightning has an incredible
capacity for destruction,
579
00:43:06,080 --> 00:43:08,360
and it can never be controlled.
580
00:43:17,400 --> 00:43:19,400
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581
00:43:19,400 --> 00:43:21,440
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