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BRIAN COX: The natural world
is beautiful
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but complex.
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The skies dance with color.
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CHILDREN: Yay! Yeah!
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COX: Shapes form
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and disappear.
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(CROWDS CHEERING)
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But this seemingly infinite complexity
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is just a shadow of something deeper,
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the underlying laws of nature.
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The world is beautiful to look at
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but it's even more
beautiful to understand.
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Come on.
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COX: A regular day in the snow.
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CHILD: Bingo! Bingo!
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COX: But if you look carefully,
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there's something deeper.
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CHILD: This is fun.
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Everyone is perfect, pretty much.
(CHUCKLING)
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Looks like they've been
cut out of thin paper.
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I got one.
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Snowflakes are complex intricate things.
They're all different,
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but there's
something similar about them.
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They are beautiful.
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But there is also, I think,
a deeper beauty,
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and that beauty is in an idea.
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The idea is that
all the similarities and difference,
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the structure of snowflakes,
can be explained
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using a few simple laws of nature.
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And that idea goes to the
very heart of science,
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because those laws themselves are
beautiful and they're universal.
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They can explain so many things
from snowflakes to stars.
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How do snowflakes form?
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Why are they all different
and yet tantalizingly similar?
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These are questions that
can be asked about any
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naturally occurring structure.
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Why are beehives regular hexagons?
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Why do icebergs float?
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Why are planets spherical?
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And what's this got to do
with free-diving grannies?
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The answers allow us to glimpse
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the underlying laws of nature
that shaped them.
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This is why when you
look at a snowflake,
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you're peering beyond
the everyday world.
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At the deep structure of nature itself.
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The universe in a snowflake.
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GIRL: Wow, it's like a little star.
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It really looks like snow crystals
stuck in a bubble.
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GIRL: (GASPS) Aww...
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(IN DISTINCT TALKING)
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Wow!
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COX: There '5 a shape that appears
at all scales in the universe.
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Seen from space,
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the Earth is a near-perfect sphere,
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sculpted by one of the
fundamental forces of nature.
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(SPEAKING OWN LANGUAGE)
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Ah!
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Carla and her friends are
about to pit themselves
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against the force that
shaped our planet.
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(SPEAKING OWN LANGUAGE)
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(CROWDS CHEERING)
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(CROWDS CHEERING)
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(CROWDS CHANTING)
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(SPEAKING OWN LANGUAGE)
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(SPEAKING OWN LANGUAGE)
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COX: These children
are going into battle
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with gravity.
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(CROWDS CHEERING)
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(CROWDS CHANTING)
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COX: Towns from across Catalonia
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have gathered to enter into
a fierce competition.
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To build a human tower
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as high as possible.
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(SPEAKING OWN LANGUAGE)
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COX: Mum and dad are
here with their daughters
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Mariana and Carla
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to represent the town of Vilafranca.
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People of all ages take part,
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but it's the lightest
members of the team,
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children as young as five,
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who ascend daringly to the summit.
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(SPEAKING OWN LANGUAGE)
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COX: The family put their trust in
the most experienced
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members of the team,
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like David Miret.
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(DAVID SPEAKING OWN LANGUAGE)
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COX: David feels the weight
of everyone above him
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as gravity pulls them
down to the ground.
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And he knows the secret
to defying gravity
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is geometry.
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COX: To support David and
eventually the kids,
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the rest of the town all push inwards
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with equal force in all directions
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buttressing the tower from all sides.
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And this results in the emergence
of a symmetrical shape
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a circle.
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No other shape gives the
tower such strength.
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But gravity
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is unforgiving.
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Ana' that's a worry if your child
is climbing to the top.
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(SPEAKING OWN LANGUAGE)
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(SPEAKING OWN LANGUAGE)
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(CROWDS APPLAUDING)
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(CROWD CHEERING)
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COX: It's clear that
the force of gravity
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is unrelenting.
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The collapsing towers
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are shadows of the process
that shaped our planet.
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These people aren't just
falling towards the ground,
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they're falling towards the
center of the Earth.
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And the Earth's gravity
pulls everything down
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from people to snowflakes,
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to the very rock that
the Earth is made of.
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And this is ultimately,
why the Earth is spherical.
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So why does gravity
sculpt things into spheres?
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Well, the first thing to say
is that it doesn't, necessarily.
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If I pick up a snowball,
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it's not spherical,
kind of an irregular shape.
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But if I apply pressure to it
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and squash it evenly in all directions,
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then I can turn that into a sphere.
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And that is what's happening
with gravity.
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As I start adding mass to it,
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that gravitational pull becomes bigger.
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So, I'll get to a point
where this snowball,
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if I kept adding mass to it,
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will be so massive
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that gravitational pull on
its surface will be so strong
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that it would start to squash the
material out of which it's made.
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In this case, snow,
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or in the case of a planet
or moon, the rock.
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That pressure exerts on the surface
equally in all directions,
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because gravity works
equally in all directions.
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Well, you can ask the question,
"How much matter do I need"
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"for gravity to get strong enough"
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"to start overcoming
the strength of rock"
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"and sculpting things into spheres?"
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Well, that minimum size has got a name,
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it's a brilliant name,
it's called the Potato Radius.
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You can see why, because things
that are too small for gravity
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to be strong enough to sculpt them
look like misshapen potatoes.
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The great thing is you don't
even need to imagine it.
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You can calculate it.
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I did that this morning.
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And I got an answer, just roughly
between 100 and 200 kilometers.
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The brilliant thing,
the most beautiful thing
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is if you look up into space
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and look at the moons of Mars
and Saturn and Jupiter
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and objects out there
in the solar system,
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you'll find that, roughly speaking,
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if their radius is bigger than
about 200 kilometers,
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they're beautiful spheres.
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And if the radius is less
than about 200 kilometers
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they look more like misshapen potatoes.
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So, you can calculate it.
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COX: If you're small,
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spheres don't come easily.
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Even asteroids or moons
don't quite manage it.
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The potato shape might be
as close as you can get.
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But when you are the size of a planet,
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spheres come naturally.
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Four and a half billion years ago,
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rocks circling the sun
began sticking together
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until they had sufficient mass for
gravity to really get to work
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turning potato shapes
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into one very important sphere
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suspended in space.
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A universal law sculpted
the familiar, elegant,
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symmetrical shape of our planet.
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But closer to the surface, it's littered
with endless shapes and forms.
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And in every one of these
naturally occurring structures,
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there are simple underlying laws
waiting to be glimpsed.
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Here in the Himalayas
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there's a shape that's a shadow
of a fundamental mathematical law.
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It's guarded by the Himalayan honey bee,
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the largest species of honey bee
on the planet.
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And collecting honey from under
their watchful compound eyes
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is one of the most dangerous
jobs you could imagine.
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(SPEAKING OWN LANGUAGE)
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And today is the first time
for one of the young villagers.
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Min and his nephew, Hiro,
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will be the ones leading the hunt
for the precious honey.
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It's prized for its medicinal
properties and sells for a high price.
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Hidden beneath the seething
mass of bodies
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sits a network of exquisitely
engineered hexagons.
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The bees appear to be master builders
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preforming structural calculations
with architectural precision.
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The bees benefit
from hidden mathematic law
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that explains why they build hexagons
to store their honey.
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And twice a year, the
Gurung people head into the mountains
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to exploit the bees' secret.
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Because it's Hiro's first time,
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this trip will be
particularity challenging.
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The bees make their hives
as inaccessible as possible
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to protect them from predators.
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(BELL CLANGING)
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The hives the bees are defending
contain a vivid visible solution
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to a deep mathematic problem
and a very practical one.
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They need to store honey
to sustain their colony
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through the long winter months.
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They build their hives out of wax.
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But for every gram of wax a bee produces
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it will have to consume
more than six grams of honey.
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So they benefit
from building efficiently
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using as little wax as possible.
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Each sting is like a hypodermic needle.
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After the bees sting, they die,
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the ultimate sacrifice to guard
the hexagons and the honey they hold.
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For Hiro, this is all about keeping
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the Gurung tradition
of honey hunting alive.
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And the hexagon
is at the heart of it all.
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So why do bees build
hexagonal honeycombs?
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Well, that is in fact
a very good question.
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It's actually a mathematical question.
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The problem is
how do I divide up a volume
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into shapes of equal size
using the minimum amount of stuff?
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Now, why does that matter to a bee?
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Because that stuff is wax and
wax is extremely valuable to the bees.
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00:23:16,840 --> 00:23:19,605
So what shape should it be?
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Should it be squares
or should it be triangles?
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You can see it can't be circles,
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because circles,
when you pack them together, leave gaps.
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So they're not very efficient.
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Or could it be that hexagons
are the most efficient?
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Well, that is actually a simple sounding
question with a very complicated answer.
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It's one of the oldest questions
in mathematics.
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It's got a name actually,
it's called the Honeycomb Conjecture.
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00:23:45,320 --> 00:23:50,042
Mathematicians have worked on it
for thousands and thousands of years,
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and it's only recently that
the Honeycomb Conjecture was proved.
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Here's one of the proofs.
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A huge paper,
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pages and pages of complex mathematics,
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and it turns out that the hexagon
is the most efficient shape.
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00:24:08,400 --> 00:24:13,850
The bees knew what human mathematicians
didn't know for thousands of years.
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00:24:13,920 --> 00:24:17,208
Actually, I'm using "know"
in quite a loose sense there.
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There's still a great deal of debate
amongst biologists
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as to how the bees actually do it.
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Do they build hexagons from scratch
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00:24:27,160 --> 00:24:30,482
using some kind
of instinctive behavior?
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00:24:30,560 --> 00:24:33,848
Or do they in fact build a simpler
shape, perhaps circles,
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00:24:33,920 --> 00:24:36,890
and then because the wax
heats up, it can deform,
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00:24:36,960 --> 00:24:41,363
and the laws of physics themselves
change the circles into hexagons.
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00:24:41,440 --> 00:24:42,965
That's still not agreed upon.
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00:24:43,520 --> 00:24:47,684
But what is agreed upon
by the mathematicians and the bees
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00:24:47,760 --> 00:24:50,081
is the hexagon is the most
efficient shape.
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00:24:50,480 --> 00:24:52,369
That just shows you
it's a beautiful thing.
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Mathematics is the universal language.
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00:24:55,960 --> 00:24:58,088
I mean, when you look
at a perfect honeycomb,
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00:24:58,160 --> 00:25:02,563
you see a shadow of that language
of mathematics
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00:25:02,640 --> 00:25:05,450
made real by bees.
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00:25:12,040 --> 00:25:14,805
Perfect shapes reveal simple laws.
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00:25:20,320 --> 00:25:23,847
Whether it's spherical planets
sculpted by gravity,
253
00:25:27,960 --> 00:25:30,088
pulling us to the center of the Earth,
254
00:25:34,800 --> 00:25:39,249
or the mathematically refined efficiency
of hexagonal honeycombs,
255
00:25:42,920 --> 00:25:46,163
simple laws underpin
the shapes we can see,
256
00:25:47,440 --> 00:25:48,851
and they're universal.
257
00:25:52,480 --> 00:25:54,448
But the action of these simple laws
258
00:25:54,560 --> 00:25:57,848
seems at odds
with the complex shapes of life.
259
00:26:10,880 --> 00:26:12,769
These shallow springs are home
260
00:26:12,840 --> 00:26:15,969
to one of nature's seemingly
less elegant shapes,
261
00:26:25,160 --> 00:26:26,207
the manatee.
262
00:26:27,640 --> 00:26:31,531
Like all marine animals, they're
free from the effects of gravity.
263
00:26:32,000 --> 00:26:34,765
No need for strong bones
to support their weight,
264
00:26:36,520 --> 00:26:39,808
but they don't have complete freedom
from the laws of physics.
265
00:26:40,120 --> 00:26:42,691
MAN: (ON RADIO) Several manatees...
266
00:26:44,800 --> 00:26:46,086
COX: It's winter,
267
00:26:46,160 --> 00:26:49,369
and if the water temperature here
drops below 20 degrees...
268
00:26:49,480 --> 00:26:51,761
WOMAN: (STATIC) Due to cold temperatures
Friday morning...
269
00:26:52,360 --> 00:26:54,328
COX: For the manatee, it's deadly.
270
00:26:54,880 --> 00:26:56,520
WOMAN: (STATIC) Can be very dangerous...
271
00:26:56,560 --> 00:26:58,801
In search of warmer
aquatic environments...
272
00:27:00,040 --> 00:27:03,931
COX: Manatees, like this female,
are vegetarians.
273
00:27:05,640 --> 00:27:09,486
Basically, she's a 10-foot-long
aquatic cow with no legs.
274
00:27:10,360 --> 00:27:13,569
To stay warm,
she has to consume up to 50 kilograms
275
00:27:13,640 --> 00:27:15,802
of leaves and sea grass every day.
276
00:27:17,160 --> 00:27:19,845
And the females here
are eating for others, too.
277
00:27:20,720 --> 00:27:23,291
This one is suckling two young calves.
278
00:27:23,920 --> 00:27:26,161
And the weather is only getting colder.
279
00:27:27,520 --> 00:27:30,285
WAYNE HARTLEY: Ooh, Lemon...
280
00:27:31,360 --> 00:27:32,441
Ruth.
281
00:27:36,600 --> 00:27:37,806
Looking good.
282
00:27:42,840 --> 00:27:45,241
Oh, there's Doug.
Doug likes it up here now.
283
00:27:46,200 --> 00:27:49,409
COX: Researcher Wayne Hartley
is doing this morning's head count,
284
00:27:49,760 --> 00:27:51,524
part of the manatee census.
285
00:27:56,320 --> 00:27:58,527
HARTLEY: It's a special thing
to come to work,
286
00:28:00,400 --> 00:28:01,481
come down in the morning
287
00:28:02,480 --> 00:28:03,481
and it's quiet.
288
00:28:04,480 --> 00:28:06,130
The steam's coming off the water.
289
00:28:11,800 --> 00:28:15,805
You can hear the manatees out there
breathing. It's just "whoosh."
290
00:28:17,720 --> 00:28:21,520
And they are so peaceful,
they are so calm.
291
00:28:23,600 --> 00:28:27,730
Just watching manatees has gotta
be good for your blood pressure
292
00:28:27,800 --> 00:28:29,643
or anything else that may ail you.
293
00:28:39,920 --> 00:28:42,605
COX: Biologist Amy Teague
is working with Wayne
294
00:28:42,680 --> 00:28:44,444
to do a health check on the families.
295
00:28:46,480 --> 00:28:49,563
AMY: He '5 just sort of hanging around,
checking things out.
296
00:28:49,640 --> 00:28:53,565
Er, manatees are very docile, uh,
gentle creatures.
297
00:28:54,360 --> 00:28:57,967
Uh, but they are very curious,
anything new in their environment
298
00:28:58,040 --> 00:28:59,804
they often like to come check out.
299
00:29:00,280 --> 00:29:03,250
Uh, so he's probably just
checking me out.
300
00:29:04,400 --> 00:29:05,920
Yeah, he's just chewing on my flipper.
301
00:29:07,120 --> 00:29:09,088
Got 23.5 degrees Celsius.
302
00:29:10,280 --> 00:29:13,329
COX: Manatee families are drawn in
from colder waters
303
00:29:13,400 --> 00:29:14,925
because this is a hot spring.
304
00:29:15,760 --> 00:29:17,888
And some make it just in time.
305
00:29:18,520 --> 00:29:20,761
He is severely cold stressed.
306
00:29:22,560 --> 00:29:24,483
HARTLEY: With the cold stress,
they don't eat.
307
00:29:25,800 --> 00:29:27,768
Their immune system shuts down.
308
00:29:28,520 --> 00:29:31,808
AMY: They're here to keep themselves
alive in the winter.
309
00:29:31,880 --> 00:29:35,043
They... They really require warm water.
310
00:29:39,680 --> 00:29:43,924
COX: It might look like these animals
keep warm using blubber, like seals,
311
00:29:45,040 --> 00:29:48,010
but they're not fat, they're round.
312
00:29:49,240 --> 00:29:53,370
In terms of pure physics, the best way
to stay warm is to be a sphere.
313
00:29:58,080 --> 00:30:02,130
It has the smallest surface
area-to-volume ratio of any shape,
314
00:30:02,960 --> 00:30:05,281
less area for heat to escape from.
315
00:30:07,040 --> 00:30:10,442
A beautiful example
with a naturally occurring shape
316
00:30:10,640 --> 00:30:13,246
reflecting a deeper mathematical law,
317
00:30:14,680 --> 00:30:17,684
the manatee could well be
the most spherical mammal on Earth.
318
00:30:18,800 --> 00:30:20,290
What a wonderful thing to be.
319
00:30:26,400 --> 00:30:27,765
Sorry, their breath stinks.
320
00:30:27,920 --> 00:30:29,160
(LAUGHS)
321
00:30:29,240 --> 00:30:31,971
HARTLEY: To me, it smells like
the inside of a hot truck tire.
322
00:30:37,080 --> 00:30:39,401
COX: But, of course,
they're not perfect spheres.
323
00:30:41,520 --> 00:30:45,081
There are many other competing factors
that determine their shape.
324
00:30:45,880 --> 00:30:49,851
Like all animals,
they have to live, breathe, eat,
325
00:30:50,600 --> 00:30:52,204
and move.
326
00:30:55,200 --> 00:30:57,931
The manatee's natural habitat
is shrinking,
327
00:30:58,600 --> 00:31:00,887
and they need to find warmth elsewhere.
328
00:31:04,720 --> 00:31:08,884
This power station helps provide energy
for around nine million people.
329
00:31:09,800 --> 00:31:10,926
And, in the process,
330
00:31:11,040 --> 00:31:14,931
warms the water that keeps over half
of Florida's manatees alive
331
00:31:15,120 --> 00:31:16,849
through the winter.
332
00:31:20,560 --> 00:31:23,006
The same families that
Wayne and Amy study
333
00:31:23,440 --> 00:31:27,081
can end up here,
over 300 kilometers away,
334
00:31:28,200 --> 00:31:31,647
where the mothers and calves
can hold on to as much heat as possible
335
00:31:33,040 --> 00:31:34,644
because of their round bodies.
336
00:31:37,520 --> 00:31:38,601
To a physicist,
337
00:31:38,680 --> 00:31:42,605
the perfect shape for a manatee
would be a symmetrical sphere,
338
00:31:43,400 --> 00:31:45,402
but biology complicates things.
339
00:31:47,280 --> 00:31:49,851
Manatees can't just bob around
waiting for food
340
00:31:49,920 --> 00:31:51,763
or warmth to come to them.
341
00:31:52,960 --> 00:31:55,611
They need fins and a tail
to move around
342
00:31:57,520 --> 00:32:00,888
whether that's to a hot spring
or to a power station.
343
00:32:12,400 --> 00:32:17,327
The forces of nature sculpts and
restricts the shapes of all things,
344
00:32:17,400 --> 00:32:21,962
the inanimate, like
pebbles or rocks or cliffs,
345
00:32:22,120 --> 00:32:23,770
or living things.
346
00:32:26,520 --> 00:32:30,286
But, of course, basic physics
is not the only force shaping life.
347
00:32:31,040 --> 00:32:32,371
(BEES BUZZING)
348
00:32:34,560 --> 00:32:38,929
Evolution by natural selection
molds living things of a time
349
00:32:39,000 --> 00:32:41,082
in response to their environment
350
00:32:41,160 --> 00:32:43,322
and their interaction
with other life forms,
351
00:32:48,200 --> 00:32:50,282
and it's had billions of years to do it.
352
00:32:53,000 --> 00:32:56,686
So, you can't understand the
shape of living things
353
00:32:56,800 --> 00:32:59,201
without understanding
their evolutionary history.
354
00:33:11,120 --> 00:33:13,521
(WOMAN SPEAKING KOREAN)
355
00:33:32,680 --> 00:33:35,251
COX: We're all the product
of our experiences.
356
00:33:35,800 --> 00:33:41,045
Our history, our culture, our lives,
make an indelible impression
357
00:33:42,120 --> 00:33:43,690
and make us all different.
358
00:33:48,840 --> 00:33:50,968
But we're also all similar,
359
00:33:51,920 --> 00:33:56,767
not just to each other as human beings
but to countless other animals on Earth.
360
00:33:57,920 --> 00:34:00,207
We are obviously related.
361
00:34:04,360 --> 00:34:08,922
Most obviously,
through the symmetry of our bodies.
362
00:34:16,600 --> 00:34:19,001
(WOMAN SPEAKING KOREAN)
363
00:34:22,760 --> 00:34:23,807
(WOMAN SPEAKING KOREAN)
364
00:34:30,000 --> 00:34:34,927
Mrs Chae and Miss Kim are Haenyo
or Women of the Sea.
365
00:34:35,000 --> 00:34:37,844
They've grown up collecting
seafood along these shores,
366
00:34:39,840 --> 00:34:40,966
and they still do.
367
00:34:41,360 --> 00:34:43,806
(WOMAN SPEAKING KOREAN)
368
00:34:47,960 --> 00:34:49,769
(LOCAL FOLK MUSIC PLAYING)
369
00:34:54,200 --> 00:34:56,521
The Haenyo are part of a
dying tradition,
370
00:34:57,200 --> 00:34:59,202
not many youngsters
are interested any more.
371
00:35:00,920 --> 00:35:04,367
It's hard work,
especially if you're in your 70s.
372
00:35:05,240 --> 00:35:06,810
(MISS KIM SPEAKING KOREAN)
373
00:35:33,080 --> 00:35:36,368
COX: Right now, the women are catching
conch or sea snails.
374
00:35:40,040 --> 00:35:44,011
It's a crucial time of year when they
have a chance to make the most money.
375
00:35:56,880 --> 00:35:59,042
The tradition of free diving for food
376
00:35:59,120 --> 00:36:01,600
is part of these women's
cultural history.
377
00:36:02,560 --> 00:36:05,086
But the details of
the human form itself,
378
00:36:05,440 --> 00:36:09,764
in particular, its symmetry
that allows them to dive, swim, and hunt
379
00:36:10,240 --> 00:36:12,561
is part of their evolutionary history.
380
00:36:17,440 --> 00:36:19,408
(SPEAKING KOREAN)
381
00:36:52,000 --> 00:36:56,562
COX: For Mrs Chae and Miss Kim,
this is all about the search for food,
382
00:37:00,640 --> 00:37:04,122
and that's where the symmetrical
structure of their bodies comes in,
383
00:37:04,720 --> 00:37:07,405
their blueprint that started out
here in the oceans
384
00:37:07,760 --> 00:37:09,888
hundreds of millions of years ago.
385
00:37:13,600 --> 00:37:16,251
Very few animals have
steered clear of it.
386
00:37:23,960 --> 00:37:25,086
(EXCLAIMS)
387
00:37:32,360 --> 00:37:34,249
(WOMAN SPEAKING KOREAN)
388
00:37:39,960 --> 00:37:43,760
COX: Life is, and always has been,
a competition.
389
00:37:44,400 --> 00:37:46,448
In a free-floating world,
390
00:37:46,600 --> 00:37:48,967
life grew to adopt
different types of symmetry
391
00:37:49,080 --> 00:37:50,320
to get what it needed.
392
00:37:53,400 --> 00:37:57,041
Some animals became round
or radially symmetric
393
00:37:57,120 --> 00:38:00,806
organizing their sensory organs
around a central axis.
394
00:38:01,840 --> 00:38:06,050
Rather than chasing down food,
they waited for food to come to them.
395
00:38:08,160 --> 00:38:13,041
But in order to really go after prey,
you need to leave that strategy behind.
396
00:38:16,600 --> 00:38:19,046
You need to be divided down the middle.
397
00:38:19,600 --> 00:38:22,922
That gives you two sides,
bilateral symmetry.
398
00:38:23,160 --> 00:38:26,164
Basically, you have a left and a right.
399
00:38:29,920 --> 00:38:31,649
And you can build on this plan,
400
00:38:31,720 --> 00:38:37,045
with arms to grab and search
and a head and a tail.
401
00:38:38,040 --> 00:38:40,520
All this means
you can orientate yourself
402
00:38:41,280 --> 00:38:43,123
and really target your prey.
403
00:38:44,080 --> 00:38:45,286
(SPEAKING KOREAN)
404
00:38:51,720 --> 00:38:56,248
COX: This body plan has been selected
for over hundreds of millions of years.
405
00:38:57,040 --> 00:38:59,327
It confers a survival advantage.
406
00:39:00,760 --> 00:39:05,607
And it turns out that all animals with
brains are bilaterally symmetrical.
407
00:39:10,520 --> 00:39:15,128
Bilateral symmetry provided the agility
that drove a spiral
408
00:39:15,240 --> 00:39:19,404
of cunning fast predators
and skittish speedy prey.
409
00:39:20,760 --> 00:39:22,888
(SPEAKING KOREAN)
410
00:39:49,680 --> 00:39:54,402
COX: The beautiful symmetry of the human
body, which we all take for granted,
411
00:39:55,080 --> 00:39:58,050
is the product of a sweeping
majestic story
412
00:39:59,960 --> 00:40:03,009
stretching back to some of the earliest
life on Earth.
413
00:40:12,840 --> 00:40:16,606
COX: So we can understand the symmetry
of organisms
414
00:40:16,680 --> 00:40:19,445
by understanding their history.
415
00:40:21,600 --> 00:40:25,889
You're essentially seeing the results of
evolution by natural selection
416
00:40:25,960 --> 00:40:30,807
over hundreds and millions,
even billions of years.
417
00:40:34,040 --> 00:40:39,251
But how do you understand the structure
and symmetry of a snowflake?
418
00:40:39,720 --> 00:40:42,246
There's no natural selection here.
419
00:40:42,320 --> 00:40:46,882
There's no DNA to record
and reproduce information.
420
00:40:47,120 --> 00:40:52,365
These things arise spontaneously
from basic laws of physics.
421
00:40:54,440 --> 00:40:56,408
GIRL: Bingo! Bingo!
422
00:40:57,240 --> 00:40:58,241
Oh, bingo!
423
00:40:59,040 --> 00:41:03,204
COX: The intricate beauty of a snowflake
is at first sight baffling,
424
00:41:03,480 --> 00:41:05,642
given the simplicity of their story.
425
00:41:06,800 --> 00:41:09,167
But in fact, it's a gift.
426
00:41:10,000 --> 00:41:12,287
A gift of almost nothing.
427
00:41:12,520 --> 00:41:14,204
One frozen moment
428
00:41:14,520 --> 00:41:17,444
that can reveal
how the underlying laws of nature
429
00:41:17,920 --> 00:41:20,844
can lead to seemingly
infinite complexity.
430
00:41:26,120 --> 00:41:30,887
Because snowflakes form in minutes and
they're made out of a single ingredient
431
00:41:31,440 --> 00:41:35,126
with strange properties
that give rise to a vast array
432
00:41:35,200 --> 00:41:40,240
of naturally occurring forms of all
shapes, sizes, and behaviors.
433
00:41:44,520 --> 00:41:45,646
Ice.
434
00:41:46,400 --> 00:41:48,084
(FOG HORN)
435
00:41:53,800 --> 00:41:57,282
NEIL RIGGS: It's so mystical when
you leave in the morning in the fog.
436
00:41:58,440 --> 00:42:00,488
You're just looking around
437
00:42:02,240 --> 00:42:04,925
and then you see these shapes
that come out of the fog.
438
00:42:05,320 --> 00:42:06,845
(FOG HORN)
439
00:42:14,840 --> 00:42:17,081
DOUG ALLAN: They are big,
big heavy objects,
440
00:42:17,160 --> 00:42:21,529
far bigger than anything that we've
created, floating on the sea.
441
00:42:26,880 --> 00:42:28,689
(FOG HORN)
442
00:42:41,840 --> 00:42:45,322
We've got to remember, it was an iceberg
that sailed passed Newfoundland
443
00:42:45,400 --> 00:42:47,562
which ended up sinking the Titanic.
444
00:42:50,840 --> 00:42:53,684
COX: Doug Allan is here
because it's iceberg season.
445
00:42:56,200 --> 00:42:58,168
He's part of a scientific expedition.
446
00:42:58,760 --> 00:43:02,606
Every summer, thousands of icebergs
float south from the Arctic
447
00:43:02,680 --> 00:43:06,571
into the shipping lanes and oil fields
off the coast of Newfoundland.
448
00:43:09,000 --> 00:43:13,722
This team are here to help protect
those multi-billion-dollar industries
449
00:43:13,800 --> 00:43:17,930
by trying to understand more
about where the icebergs are heading.
450
00:43:18,960 --> 00:43:22,009
The man leading the expedition
is Neil Riggs.
451
00:43:22,240 --> 00:43:24,129
So, we put it back
in the water again, OK,
452
00:43:24,200 --> 00:43:27,522
and if we lose control,
then we take it in, we secure it.
453
00:43:27,640 --> 00:43:29,688
And if that goes nowhere, we go home.
454
00:43:32,880 --> 00:43:35,486
COX: The big problem with icebergs
is simple.
455
00:43:35,840 --> 00:43:37,171
They float.
456
00:43:44,600 --> 00:43:49,003
RIGGS: Iceberg ice reflects radar
69 times less effectively
457
00:43:49,080 --> 00:43:51,287
than a ship with the
same cross-sectional area.
458
00:43:53,760 --> 00:43:55,922
(INDISTINCT)
459
00:43:57,680 --> 00:44:00,570
So, you could be sailing along
and doing very good seamanship,
460
00:44:00,680 --> 00:44:02,696
looking at your radar,
and there's the thing, all of a sudden,
461
00:44:02,720 --> 00:44:03,926
and you're upon it.
462
00:44:04,080 --> 00:44:07,482
And it's still a massive piece of ice
relative to your ship.
463
00:44:07,720 --> 00:44:10,326
So, it could make a nice little hole.
464
00:44:11,920 --> 00:44:14,491
COX: The team will have to
understand the influence
465
00:44:14,600 --> 00:44:17,570
of a large number of variables
if they are to distinguish
466
00:44:17,640 --> 00:44:20,723
between harmless icebergs
and dangerous ones.
467
00:44:21,760 --> 00:44:23,056
ALLAN: It's a complicated jigsaw.
468
00:44:23,080 --> 00:44:25,447
It's a little bit...
You could think of it as a crime scene
469
00:44:25,520 --> 00:44:28,967
where you have the forensic people go in
and they pick up little bits of clues,
470
00:44:29,040 --> 00:44:31,122
and together, you make a bigger picture.
471
00:44:32,560 --> 00:44:36,121
What I'm doing is just adding my little
piece to the overall picture
472
00:44:36,200 --> 00:44:40,489
and hopefully helping their mathematical
models to be more real.
473
00:44:42,840 --> 00:44:45,161
COX: Doug is a
specialist cold-water diver.
474
00:44:46,240 --> 00:44:49,722
It's his job to photograph
the underside of the icebergs.
475
00:44:50,440 --> 00:44:51,771
We'll go over to some of those
476
00:44:51,840 --> 00:44:53,330
- smaller pieces.
- OK.
477
00:44:53,400 --> 00:44:54,401
OK.
478
00:44:54,960 --> 00:44:57,456
Yes, Captain Manning, we are OK to put
the divers in the water now...
479
00:44:57,480 --> 00:44:59,721
COX: Rick Stanley
is looking after safety.
480
00:45:05,520 --> 00:45:06,776
RICK STANLEY:
Who knows what's gonna happen.
481
00:45:06,800 --> 00:45:12,807
There's so much pressure in this ice
that it blows, it explodes.
482
00:45:13,040 --> 00:45:17,568
But there's pressure in there that
can blow a piece of iceberg off the ice
483
00:45:17,640 --> 00:45:19,404
probably 15 or 20 feet.
484
00:45:19,640 --> 00:45:22,041
(RUMBLING)
485
00:45:26,560 --> 00:45:29,086
ALLAN: And we were just
puttering around and suddenly,
486
00:45:29,160 --> 00:45:32,084
with no warning at all,
the whole thing split in half,
487
00:45:32,160 --> 00:45:35,369
and it was almost like it was
all falling into each other.
488
00:45:43,440 --> 00:45:45,488
This might be a bit unstable.
489
00:45:45,560 --> 00:45:47,050
- I'm not...
- This is a huge berg.
490
00:45:47,920 --> 00:45:51,083
I'd rather dive round one
that wasn't falling apart.
491
00:45:51,200 --> 00:45:52,201
Yeah.
492
00:45:55,920 --> 00:45:58,287
COX: These giant frozen mountains
493
00:45:58,360 --> 00:46:00,931
are born from
the most innocent beginnings.
494
00:46:06,400 --> 00:46:07,731
Snowflakes.
495
00:46:10,240 --> 00:46:14,404
Over thousands of years,
they're compressed to form glaciers
496
00:46:14,760 --> 00:46:17,411
that then break off to form icebergs.
497
00:46:18,040 --> 00:46:21,931
An average one weighs 200,000 tonnes.
498
00:46:23,800 --> 00:46:28,249
And that, give or take,
is around 100 trillion snowflakes
499
00:46:28,320 --> 00:46:32,006
that form the structures
that the expedition is trying to model,
500
00:46:32,080 --> 00:46:37,086
using a combination of sonar robots
and Doug's first-hand observations.
501
00:46:39,200 --> 00:46:41,885
ALLAN: I basically have a good look
at one side of the berg
502
00:46:41,960 --> 00:46:44,566
between the surface and 30 meters.
503
00:46:44,760 --> 00:46:48,082
Tell them what I saw and it will
mean that they can interpret
504
00:46:48,200 --> 00:46:49,440
the sonar data that comes back.
505
00:46:49,520 --> 00:46:52,330
They'll get a better idea of it
if I've seen it for myself.
506
00:47:21,800 --> 00:47:25,282
It's quite eerie going down
the side of the iceberg.
507
00:47:26,840 --> 00:47:31,880
You're going down into the darkness,
into the blue, into the green,
508
00:47:37,640 --> 00:47:41,008
and very occasionally
there'll be this really loud thump,
509
00:47:41,080 --> 00:47:44,289
just like someone had hit you with
the flat of their hand
510
00:47:44,360 --> 00:47:45,725
in the center of your chest,
511
00:47:47,440 --> 00:47:50,091
where the iceberg is banging
on the bottom.
512
00:47:58,680 --> 00:48:00,603
You really don't want to go too far down
513
00:48:00,680 --> 00:48:04,730
because there is a real danger of being
squished by the iceberg underneath.
514
00:48:09,960 --> 00:48:13,931
Well, you always worry when divers are
in the water. But iceberg diving
515
00:48:14,000 --> 00:48:18,642
there's even more of that anticipation
and excitement that goes on
516
00:48:18,720 --> 00:48:20,722
in the lower part of your belly.
517
00:48:29,840 --> 00:48:32,684
ALLAN: So you're swimming
and you begin to see the details.
518
00:48:32,760 --> 00:48:35,730
You begin to realize that this is not
519
00:48:35,800 --> 00:48:38,929
a flat wall of ice
going into the depths.
520
00:48:39,000 --> 00:48:41,731
This has tiny little dimples on it.
Which...
521
00:48:41,800 --> 00:48:44,531
It almost looks like a giant golf ball.
522
00:48:50,840 --> 00:48:53,411
COX: These features are added to
the models
523
00:48:53,480 --> 00:48:56,529
to understand how they affect
the way the icebergs float
524
00:48:56,600 --> 00:49:00,525
and travel over long distances
and into the shipping lanes.
525
00:49:02,480 --> 00:49:05,643
It's good to contribute to science
at a basic level like this
526
00:49:05,720 --> 00:49:07,802
when the science is still developing,
527
00:49:07,880 --> 00:49:10,406
to come in, take some shots
which help the scientists.
528
00:49:10,480 --> 00:49:11,527
That's really useful.
529
00:49:17,240 --> 00:49:19,163
COX: For all their unpredictability,
530
00:49:19,520 --> 00:49:22,888
there is regularity
in the behavior of icebergs
531
00:49:25,760 --> 00:49:30,084
if you look carefully
and ask the right questions,
532
00:49:30,520 --> 00:49:33,091
which is what science is all about.
533
00:49:39,120 --> 00:49:41,282
And the simplest question of all
534
00:49:41,360 --> 00:49:44,330
is about the most obvious part
of their behavior.
535
00:49:47,360 --> 00:49:48,850
Why does ice float?
536
00:49:51,080 --> 00:49:52,650
That's not a naive question
537
00:49:52,720 --> 00:49:57,044
because no other commonly occurring
solid floats on its own liquid.
538
00:49:59,160 --> 00:50:03,210
The answer lies in the structure
of the water molecule itself.
539
00:50:04,800 --> 00:50:08,282
Think of what a molecule is.
Take a water molecule, for example.
540
00:50:08,880 --> 00:50:12,521
It's two hydrogen atoms
stuck to an oxygen atom.
541
00:50:12,880 --> 00:50:15,247
That's two hydrogen nuclei,
542
00:50:15,560 --> 00:50:17,642
which have positive electric charge
543
00:50:18,040 --> 00:50:20,611
sticking to an oxygen nucleus,
544
00:50:20,680 --> 00:50:22,728
which has a positive electric charge.
545
00:50:22,800 --> 00:50:26,282
And they are surrounded
by negatively charged electrons.
546
00:50:26,360 --> 00:50:28,681
That's what sticks the atoms together.
547
00:50:28,960 --> 00:50:31,008
See, the negatively charged electrons
548
00:50:31,080 --> 00:50:34,801
tend to cluster
around the oxygen nucleus
549
00:50:34,880 --> 00:50:41,490
leaving those two legs of hydrogen
slightly positively charged.
550
00:50:41,680 --> 00:50:43,967
That means those positive charges
551
00:50:44,040 --> 00:50:47,931
can attract other
negatively charged ends
552
00:50:48,000 --> 00:50:49,843
of other water molecules.
553
00:50:49,920 --> 00:50:54,847
So, an oxygen can come and
orientate itself and bond to that leg.
554
00:50:55,240 --> 00:50:58,323
The other side, another oxygen
from another water molecule
555
00:50:58,400 --> 00:51:02,405
will be attracted to the positive charge
and bond to that leg.
556
00:51:02,480 --> 00:51:05,529
On the top, you get a hydrogen in
and bond into that leg.
557
00:51:05,600 --> 00:51:07,921
So, you can see,
you build up a structure.
558
00:51:08,000 --> 00:51:09,843
An open crystal structure.
559
00:51:10,200 --> 00:51:13,329
A shape which is actually hexagonal.
560
00:51:13,600 --> 00:51:17,082
And it's that property,
that open structure,
561
00:51:17,160 --> 00:51:20,004
which is a reflection
of the underlying structure
562
00:51:20,080 --> 00:51:22,082
of the water molecule itself,
563
00:51:22,160 --> 00:51:27,883
that leads to the solid ice
being less dense than the liquid.
564
00:51:28,160 --> 00:51:34,964
And that is why ice cubes and icebergs
float on liquid water.
565
00:51:39,040 --> 00:51:41,407
The hexagonal structure of ice
566
00:51:41,520 --> 00:51:46,003
is a shadow of the forces of nature
that hold molecules together.
567
00:51:50,040 --> 00:51:53,681
Forces that shape
every molecule of water
568
00:51:54,920 --> 00:51:59,084
and that create
the six-fold symmetry of snowflakes.
569
00:52:03,640 --> 00:52:07,770
You can tell they're all the same thing.
They're all six-sided.
570
00:52:09,120 --> 00:52:12,203
And yet, you can also see, just by eye,
571
00:52:12,280 --> 00:52:15,648
that every one is different,
some are radically different.
572
00:52:16,240 --> 00:52:21,246
It's very difficult to imagine
how all this beauty and complexity
573
00:52:21,320 --> 00:52:26,884
could emerge spontaneously
from a few simple laws of nature.
574
00:52:31,720 --> 00:52:34,007
As snowflakes fall through the sky,
575
00:52:34,080 --> 00:52:37,562
they form and grow around
a symmetrical framework.
576
00:52:39,880 --> 00:52:46,490
So if you start with an ice crystal
and some part of it has got a flat bit,
577
00:52:47,000 --> 00:52:50,322
part of the hexagon, if you like,
and some bits a bit rough,
578
00:52:50,720 --> 00:52:54,008
then water molecules
are more likely to bind
579
00:52:54,080 --> 00:52:55,923
to the rough bit than the flat bit.
580
00:52:56,240 --> 00:53:00,768
There are basically more ways for them,
more sites for them to stick to.
581
00:53:00,880 --> 00:53:02,325
So, that means that the rough bits
582
00:53:02,400 --> 00:53:05,609
will accumulate more molecules
than the flat bits,
583
00:53:05,680 --> 00:53:09,048
and it will build up faster
until it gets flat.
584
00:53:09,120 --> 00:53:10,360
And then, it will slow down.
585
00:53:10,440 --> 00:53:15,002
So, there's a tendency
for the underlying structure
586
00:53:15,080 --> 00:53:19,802
of the ice crystals themselves to get
echoed into bigger and bigger units.
587
00:53:21,200 --> 00:53:25,728
Then, there's a second process called
branching or the branch instability.
588
00:53:26,000 --> 00:53:27,809
That happens when the snowflake
589
00:53:28,000 --> 00:53:31,288
goes into a particularly
humid region in a cloud.
590
00:53:31,440 --> 00:53:34,603
So, that's a region where there are
lots of water molecules available.
591
00:53:34,960 --> 00:53:38,043
So, you get a little bump
on the flat surface.
592
00:53:38,480 --> 00:53:44,010
That bump is more likely to have
water molecules bind to it.
593
00:53:44,080 --> 00:53:46,128
It's got more binding sites,
if you like,
594
00:53:46,200 --> 00:53:47,406
so it will grow quickly
595
00:53:47,480 --> 00:53:50,006
if there are lots of
water molecules available.
596
00:53:50,080 --> 00:53:52,003
So, it will grow into a spike,
597
00:53:52,080 --> 00:53:55,482
and then other bumps can appear,
and they'll grow into spikes.
598
00:53:55,560 --> 00:54:00,726
So that's how you get that star-like
sharp structures on snowflakes.
599
00:54:01,840 --> 00:54:06,209
But, then, if the snowflake drifts back
into a region that's less humid,
600
00:54:06,280 --> 00:54:08,567
so there are less
water molecules available,
601
00:54:08,640 --> 00:54:10,847
then the faceting takes over again.
602
00:54:11,080 --> 00:54:15,051
And smooth edges,
hexagonal structures start to form.
603
00:54:15,400 --> 00:54:17,323
Then, it goes into a humid region,
604
00:54:17,400 --> 00:54:20,882
and the branching takes over
and you get the branches.
605
00:54:28,760 --> 00:54:31,730
It's a wonderfully complex
and intricate process.
606
00:54:31,920 --> 00:54:34,161
And the thing I find
most beautiful about it
607
00:54:34,240 --> 00:54:39,041
is that when you look at a snowflake,
then you can read its entire history.
608
00:54:39,120 --> 00:54:42,363
You can see its history made solid.
609
00:54:45,040 --> 00:54:48,965
Every individual snowflake
has a different history.
610
00:54:49,240 --> 00:54:50,651
Every snowflake
611
00:54:50,720 --> 00:54:54,725
followed a slightly different path
through the clouds onto the ground.
612
00:54:54,840 --> 00:55:00,404
And that means every snowflake grew
in a subtly different way.
613
00:55:00,480 --> 00:55:04,246
And that's why no two snowflakes
are ever alike,
614
00:55:04,320 --> 00:55:08,848
because no two paths through time
are ever alike.
615
00:55:16,480 --> 00:55:20,041
COX: When you look at a snowflake,
you see history
616
00:55:20,120 --> 00:55:26,207
and the deep structure of nature
condensed into a frozen moment.
617
00:55:29,000 --> 00:55:31,446
CHILD: Look how many stars
it is together.
618
00:55:32,480 --> 00:55:34,926
WOMAN: You can see them so clearly.
619
00:55:36,720 --> 00:55:38,290
You look.
620
00:55:38,760 --> 00:55:41,286
COX: It is wonderful, you know,
that when you think about it,
621
00:55:41,360 --> 00:55:45,843
the whole universe, the whole of physics
is contained in a snowflake.
622
00:55:46,880 --> 00:55:50,930
To describe them,
you need all four forces of nature.
623
00:55:51,000 --> 00:55:54,766
You need gravity to allow the snowflake
to fall down
624
00:55:54,840 --> 00:55:56,729
through the clouds and onto the ground.
625
00:55:56,800 --> 00:55:58,643
You need electro magnetism
626
00:55:58,720 --> 00:56:01,610
to stick all those
water molecules together
627
00:56:01,680 --> 00:56:04,604
to form these beautiful crystals.
628
00:56:04,680 --> 00:56:08,446
You need the nuclear forces
to stick the atomic nuclei
629
00:56:08,520 --> 00:56:10,363
of oxygen together.
630
00:56:10,440 --> 00:56:14,411
And then you need
to understand about symmetry
631
00:56:14,480 --> 00:56:16,403
and symmetry breaking.
632
00:56:16,480 --> 00:56:19,927
All the fundamental ideas
that underline modern physics
633
00:56:20,000 --> 00:56:23,891
can be thought of in the journey
of a snowflake to the ground.
634
00:56:27,120 --> 00:56:30,329
Oh, look, how many stars
do you think there are?
635
00:56:30,400 --> 00:56:32,129
Oh, wow!
636
00:56:34,520 --> 00:56:38,320
COX: Every snowflake
shares the same building blocks,
637
00:56:38,400 --> 00:56:43,042
the same basic beautiful symmetric
forces of nature
638
00:56:43,120 --> 00:56:44,724
at their heart.
639
00:56:44,800 --> 00:56:47,724
But because of their histories,
because of the way they formed,
640
00:56:47,800 --> 00:56:49,245
they're all different.
641
00:56:49,320 --> 00:56:53,166
And so it is with solar systems,
so it is with planets,
642
00:56:53,240 --> 00:56:55,049
and so it is with people.
643
00:56:55,120 --> 00:56:57,327
We're all made out of
the same building blocks,
644
00:56:57,400 --> 00:57:01,246
but we're all slightly
and magnificently different
645
00:57:01,320 --> 00:57:03,766
because of the history of our formation.
646
00:57:11,480 --> 00:57:15,201
The structures we see in the universe,
stars and planets
647
00:57:15,320 --> 00:57:17,607
and trees and snowflakes
648
00:57:17,680 --> 00:57:19,921
are shadows of something deeper.
649
00:57:22,040 --> 00:57:26,762
They mask an underlying
beauty and simplicity.
650
00:57:28,360 --> 00:57:33,764
But isn't it a beautiful thought
that our origin and evolution,
651
00:57:34,200 --> 00:57:37,249
just like the structure of a snowflake
652
00:57:37,320 --> 00:57:39,926
in a snow storm, can be explained
653
00:57:40,000 --> 00:57:43,402
by a few simple natural laws.
654
00:57:43,800 --> 00:57:46,007
And isn't it a wonderful idea
655
00:57:46,080 --> 00:57:50,529
that that thought came from
just looking carefully at nature
656
00:57:50,600 --> 00:57:52,329
and trying to understand it.
657
00:57:57,000 --> 00:57:59,002
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54296
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