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The natural world is beautiful...
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00:00:11,640 --> 00:00:12,840
...but complex.
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00:00:17,040 --> 00:00:19,679
The skies dance with colour.
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00:00:19,680 --> 00:00:22,359
Yay! Yes!
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00:00:22,360 --> 00:00:23,920
Shapes form...
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00:00:25,560 --> 00:00:26,600
...and disappear.
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00:00:31,800 --> 00:00:34,399
But this seemingly infinite
complexity
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00:00:34,400 --> 00:00:36,480
is just a shadow
of something deeper.
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00:00:37,560 --> 00:00:39,360
The underlying laws of nature.
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00:00:46,080 --> 00:00:48,999
The world is beautiful to look at.
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00:00:49,000 --> 00:00:51,560
But it's even more beautiful
to understand.
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00:01:16,720 --> 00:01:18,200
Come on.
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00:01:22,480 --> 00:01:24,160
A regular day in the snow.
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00:01:29,400 --> 00:01:31,599
But if you look carefully,
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00:01:31,600 --> 00:01:32,920
there's something deeper.
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00:01:37,600 --> 00:01:38,800
This is fun!
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00:01:42,160 --> 00:01:43,720
Every one...
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00:01:44,920 --> 00:01:48,039
...is perfect, pretty much.
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00:01:48,040 --> 00:01:50,360
It looks like they've been cut out
of thin paper.
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00:01:53,640 --> 00:01:54,920
I got one.
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00:01:57,040 --> 00:02:00,719
Snowflakes are complex,
intricate things.
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00:02:00,720 --> 00:02:04,479
They are all different but there's
something similar about them.
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00:02:04,480 --> 00:02:06,479
They are beautiful,
24
00:02:06,480 --> 00:02:08,959
but there is also, I think,
a deeper beauty.
25
00:02:08,960 --> 00:02:11,199
And that beauty is in an idea.
26
00:02:11,200 --> 00:02:15,239
The idea is that all
the similarities and difference,
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00:02:15,240 --> 00:02:18,239
the structure of snowflakes
can be explained
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00:02:18,240 --> 00:02:21,359
using a few simple laws of nature.
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00:02:21,360 --> 00:02:24,159
And that idea goes to
the very heart of science,
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00:02:24,160 --> 00:02:27,959
because those laws themselves
are beautiful,
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00:02:27,960 --> 00:02:29,439
and they're universal.
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00:02:29,440 --> 00:02:32,599
They can explain so many things,
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from snowflakes to stars.
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00:02:38,800 --> 00:02:40,520
How do snowflakes form?
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00:02:42,280 --> 00:02:44,079
Why are they all different,
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and yet tantalisingly similar?
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00:02:50,560 --> 00:02:52,359
These are questions
that can be asked
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00:02:52,360 --> 00:02:54,880
about any
naturally occurring structure.
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00:02:58,360 --> 00:03:00,560
Why are beehives regular hexagons?
40
00:03:01,720 --> 00:03:03,160
Why do icebergs float?
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00:03:04,120 --> 00:03:05,560
Why are planets spherical?
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00:03:06,560 --> 00:03:09,080
And what has this got to do
with free-diving grannies?
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00:03:12,800 --> 00:03:16,919
The answers allow us to glimpse the
underlying laws of nature
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00:03:16,920 --> 00:03:18,120
that shape them.
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00:03:22,760 --> 00:03:25,360
This is why,
when you look at a snowflake...
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00:03:28,120 --> 00:03:30,320
...you're peering beyond
the everyday world...
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00:03:31,320 --> 00:03:34,240
...at the deep structure
of nature itself.
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00:03:36,000 --> 00:03:37,760
The universe in a snowflake.
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00:03:45,520 --> 00:03:47,759
Wow! I can see a star!
50
00:03:47,760 --> 00:03:51,159
It really looks like snow crystals
stuck to the bubble.
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00:03:51,160 --> 00:03:54,400
Oh! Wow!
52
00:03:58,560 --> 00:04:02,360
There's a shape that appears
at all scales in the universe.
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00:04:07,520 --> 00:04:10,800
Seen from space, the Earth is a near
perfect sphere...
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00:04:14,560 --> 00:04:17,840
...sculpted by one of the
fundamental forces of nature.
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00:04:44,480 --> 00:04:47,119
Carla and her friends are about to
pit themselves
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00:04:47,120 --> 00:04:49,520
against the force
that shaped our planet.
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00:05:51,760 --> 00:05:54,080
These children
are going into battle...
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00:05:55,320 --> 00:05:56,400
...with gravity.
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00:06:10,400 --> 00:06:12,400
Towns from across Catalonia...
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00:06:14,640 --> 00:06:17,440
...have gathered to enter into a
fierce competition...
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00:06:20,720 --> 00:06:23,920
...to build a human tower
as high as possible.
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00:06:32,520 --> 00:06:36,319
Mum and Dad are here with
their daughters, Mariana and Carla,
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00:06:36,320 --> 00:06:38,560
to represent the town
of Vilafranca.
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00:06:42,640 --> 00:06:44,679
People of all ages take part,
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00:06:44,680 --> 00:06:46,959
but it's the lightest members
of the team,
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00:06:46,960 --> 00:06:48,959
children as young as five,
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00:06:48,960 --> 00:06:51,280
who ascend daringly to the summit.
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00:07:00,960 --> 00:07:02,479
The family put their trust
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00:07:02,480 --> 00:07:07,200
in the most experienced members of
the team, like David Merit.
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00:07:39,640 --> 00:07:42,240
David feels the weight of everyone
above him...
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00:07:45,600 --> 00:07:48,040
...as gravity pulls them
down to the ground.
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00:07:52,080 --> 00:07:56,320
And he knows the secret
to defying gravity is geometry.
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00:08:08,120 --> 00:08:11,239
To support David,
and eventually the kids,
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00:08:11,240 --> 00:08:14,039
the rest of the town
all push inwards
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00:08:14,040 --> 00:08:17,119
with equal force,
in all directions,
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00:08:17,120 --> 00:08:19,440
buttressing the tower
from all sides.
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00:08:23,920 --> 00:08:27,200
And this results in the emergence of
a symmetrical shape.
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00:08:28,440 --> 00:08:30,039
A circle.
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00:08:30,040 --> 00:08:32,960
No other shape gives the tower
such strength.
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00:08:44,920 --> 00:08:47,520
But gravity is unforgiving.
81
00:09:20,920 --> 00:09:24,440
And that's a worry if your child
is climbing to the top.
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00:10:59,080 --> 00:11:02,680
It's clear that the force of gravity
is unrelenting.
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00:11:07,560 --> 00:11:12,440
The collapsing towers are shadows of
the process that shaped our planet.
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00:11:17,560 --> 00:11:20,600
These people aren't just
falling towards the ground.
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00:11:23,000 --> 00:11:25,640
They're falling towards the centre
of the Earth.
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00:11:26,640 --> 00:11:29,040
And the Earth's gravity
pulls everything down.
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00:11:31,800 --> 00:11:33,840
From people to snowflakes...
88
00:11:38,120 --> 00:11:40,680
...to the very rock
that the Earth is made of.
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00:11:42,080 --> 00:11:45,280
And this is ultimately
why the Earth is spherical.
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00:11:47,640 --> 00:11:51,199
So why does gravity
sculpt things into spheres?
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00:11:51,200 --> 00:11:55,040
Well, the first thing to say
is that it doesn't, necessarily.
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00:11:57,560 --> 00:11:59,000
If I pick up a snowball...
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00:12:01,080 --> 00:12:03,800
...it's not spherical.
Kind of an irregular shape.
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00:12:05,880 --> 00:12:08,279
But if I apply pressure to it,
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squash it, evenly,
in all directions...
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00:12:13,240 --> 00:12:16,279
...then I can turn that
into a sphere.
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00:12:16,280 --> 00:12:19,839
And that is
what's happening with gravity.
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00:12:19,840 --> 00:12:21,959
As I start adding mass to it,
99
00:12:21,960 --> 00:12:25,119
that gravitational pull
becomes bigger,
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00:12:25,120 --> 00:12:27,919
so I'll get to a point
where this snowball,
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00:12:27,920 --> 00:12:29,679
if I kept adding mass to it,
102
00:12:29,680 --> 00:12:33,519
would be so massive that the
gravitational pull on its surface
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00:12:33,520 --> 00:12:38,159
would be so strong that it would
start to squash the material
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00:12:38,160 --> 00:12:39,799
out of which it is made.
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00:12:39,800 --> 00:12:41,279
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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00:12:50,200 --> 00:12:54,200
because gravity works equally
in all directions.
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00:12:55,480 --> 00:12:56,879
You could ask the question,
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00:12:56,880 --> 00:13:00,359
how much matter do I need
for gravity to get strong enough
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00:13:00,360 --> 00:13:03,239
to start overcoming
the strength of rock,
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00:13:03,240 --> 00:13:05,559
and sculpting things
into spheres?
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00:13:05,560 --> 00:13:09,399
Well, that minimum size
has got a name.
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It's a brilliant name.
It is called the potato radius.
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00:13:11,840 --> 00:13:13,079
You can see why.
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00:13:13,080 --> 00:13:17,159
Because things that are too small
for gravity to be strong enough
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to sculpt them
look like misshapen potatoes.
118
00:13:23,440 --> 00:13:26,480
The great thing is
you don't even need to imagine it.
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00:13:27,560 --> 00:13:29,039
You can calculate it.
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00:13:29,040 --> 00:13:32,039
I did that this morning,
and I got an answer, just roughly,
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of between 100 and 200km.
122
00:13:34,520 --> 00:13:36,159
The brilliant thing,
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00:13:36,160 --> 00:13:39,479
the most beautiful thing is if you
look up into space,
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00:13:39,480 --> 00:13:42,199
and look at the moons
of Mars and Saturn and Jupiter,
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00:13:42,200 --> 00:13:44,919
and objects out there in
the solar system,
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00:13:44,920 --> 00:13:47,399
you'll find that, roughly speaking,
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00:13:47,400 --> 00:13:50,479
if their radius is bigger
than about 200km,
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they're beautiful spheres,
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00:13:52,040 --> 00:13:55,199
and if their radius is less
than about 200km,
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00:13:55,200 --> 00:13:58,199
they look more like
misshapen potatoes.
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00:13:58,200 --> 00:14:00,120
So you can calculate it.
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00:14:04,680 --> 00:14:07,840
If you're small,
spheres don't come easily.
133
00:14:11,400 --> 00:14:14,759
Even asteroids or moons
don't quite manage it.
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00:14:14,760 --> 00:14:18,120
The potato shape might be
as close as you can get.
135
00:14:23,760 --> 00:14:27,080
But when you're the size of a
planet, spheres come naturally.
136
00:14:35,520 --> 00:14:37,719
4.5 billion years ago,
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00:14:37,720 --> 00:14:41,639
rocks circling the sun
began sticking together,
138
00:14:41,640 --> 00:14:45,320
until they had sufficient mass
for gravity to really get to work...
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00:14:46,440 --> 00:14:50,839
...turning potato shapes into one
very important sphere,
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00:14:50,840 --> 00:14:52,120
suspended in space.
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00:14:59,000 --> 00:15:02,999
A universal law
sculpted the familiar, elegant,
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00:15:03,000 --> 00:15:04,920
symmetrical shape of our planet.
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00:15:12,760 --> 00:15:14,759
But closer to the surface,
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00:15:14,760 --> 00:15:18,040
it's littered with endless shapes
and forms.
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00:15:22,440 --> 00:15:25,999
And in every one of these
naturally occurring structures,
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00:15:26,000 --> 00:15:30,360
there are a simple, underlying laws
waiting to be glimpsed.
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00:15:36,560 --> 00:15:37,759
Here in the Himalayas,
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00:15:37,760 --> 00:15:42,160
there's a shape that's a shadow of
a fundamental mathematical law.
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00:15:45,680 --> 00:15:47,920
It's guarded by
the Himalayan honeybee.
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00:15:51,600 --> 00:15:54,320
The largest species of honeybee
on the planet.
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00:15:56,720 --> 00:16:01,119
And collecting honey from under
their watchful compound eyes
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00:16:01,120 --> 00:16:03,720
is one of the most dangerous jobs
you could imagine.
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00:16:24,440 --> 00:16:27,240
And today is the first time
for one of the young villagers.
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00:16:28,240 --> 00:16:31,839
Min and his nephew Hira will be the
ones leading the hunt
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for the precious honey.
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00:16:33,640 --> 00:16:36,359
It's prized
for its medicinal properties,
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00:16:36,360 --> 00:16:37,960
and sells for a high price.
158
00:16:52,520 --> 00:16:55,439
Hidden beneath
the seething mass of bodies
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00:16:55,440 --> 00:16:58,920
sits a network of
exquisitely engineered hexagons.
160
00:17:03,840 --> 00:17:06,399
The bees appear to be
master builders,
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00:17:06,400 --> 00:17:10,560
performing structural calculations
with architectural precision.
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00:17:24,280 --> 00:17:27,759
The bees benefit from a hidden
mathematical law
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that explains why they build
hexagons to store their honey.
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00:17:32,080 --> 00:17:35,879
And twice a year, the Gurung people
head into the mountains
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to exploit the bees' secret.
166
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Because it's Hira's first time,
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this trip will be
particularly 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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00:19:10,160 --> 00:19:12,359
The hives the bees are defending
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00:19:12,360 --> 00:19:17,839
contain a vivid, visible solution to
a deep mathematical problem,
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00:19:17,840 --> 00:19:19,320
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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00:19:26,720 --> 00:19:28,560
They build their hives out of wax.
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00:19:30,760 --> 00:19:33,959
But for every gram of wax
a bee produces,
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00:19:33,960 --> 00:19:37,200
it will have to consume more than
six grams of honey.
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00:19:40,120 --> 00:19:42,959
So they benefit
from building efficiently,
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using as little wax as possible.
180
00:20:39,880 --> 00:20:43,000
Each sting is
like a hypodermic needle.
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00:20:44,280 --> 00:20:46,720
After the bees sting, they die.
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The ultimate sacrifice
to guard the hexagons
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00:20:53,160 --> 00:20:54,920
and the honey they hold.
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00:22:15,200 --> 00:22:16,679
For Hira, this is all about
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00:22:16,680 --> 00:22:20,320
keeping the Gurung tradition
of honey hunting alive.
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00:22:23,440 --> 00:22:26,360
And the hexagon is
at the heart of it all.
187
00:22:45,840 --> 00:22:48,840
So why DO bees
build hexagonal honeycombs?
188
00:22:51,240 --> 00:22:54,039
Well, that is, in fact,
a very good question.
189
00:22:54,040 --> 00:22:55,880
It's actually
a mathematical question.
190
00:22:58,600 --> 00:22:59,879
The problem is,
191
00:22:59,880 --> 00:23:05,039
how do I divide up a volume into
shapes of equal size
192
00:23:05,040 --> 00:23:07,000
using the minimum amount of stuff?
193
00:23:08,120 --> 00:23:10,639
Now, why does that matter to a bee?
194
00:23:10,640 --> 00:23:12,159
Because that stuff is wax,
195
00:23:12,160 --> 00:23:15,599
and wax is extremely valuable
to the bees.
196
00:23:15,600 --> 00:23:18,879
So, what shape should it be?
197
00:23:18,880 --> 00:23:20,919
Should it be squares?
198
00:23:20,920 --> 00:23:22,559
Or should it be triangles?
199
00:23:22,560 --> 00:23:24,079
You can see it can't be circles
200
00:23:24,080 --> 00:23:26,079
because circles,
when you pack them together,
201
00:23:26,080 --> 00:23:28,479
leave gaps,
so they're not very efficient.
202
00:23:28,480 --> 00:23:32,879
Or could it be that
hexagons are the most efficient?
203
00:23:32,880 --> 00:23:36,319
Well, that is actually a simple
sounding question,
204
00:23:36,320 --> 00:23:38,479
with a very complicated answer.
205
00:23:38,480 --> 00:23:41,119
It's one of the oldest
questions in mathematics.
206
00:23:41,120 --> 00:23:42,479
It's got a name, actually.
207
00:23:42,480 --> 00:23:44,399
It's called
the honeycomb conjecture.
208
00:23:44,400 --> 00:23:49,359
Mathematicians have worked on it for
thousands and thousands of years,
209
00:23:49,360 --> 00:23:53,320
and it's only recently that the
honeycomb conjecture was proved.
210
00:23:54,360 --> 00:23:55,560
Here is one of the proofs.
211
00:23:56,960 --> 00:23:58,120
A huge paper.
212
00:23:59,120 --> 00:24:02,120
Pages and pages
of complex mathematics...
213
00:24:03,240 --> 00:24:07,279
...and it turns out that the hexagon
IS the most efficient shape.
214
00:24:07,280 --> 00:24:11,559
The bees knew what human
mathematicians didn't know
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00:24:11,560 --> 00:24:12,999
for thousands of years.
216
00:24:13,000 --> 00:24:16,119
Actually, I'm using "know"
in quite a loose sense, there.
217
00:24:16,120 --> 00:24:19,719
There's still a great deal of debate
amongst biologists
218
00:24:19,720 --> 00:24:22,239
as to how the bees actually do it.
219
00:24:22,240 --> 00:24:26,239
Do they build hexagons from scratch
220
00:24:26,240 --> 00:24:29,439
using some kind of
instinctive behaviour?
221
00:24:29,440 --> 00:24:31,359
Or do they in fact build
a simpler shape?
222
00:24:31,360 --> 00:24:35,959
Perhaps circles, and then, because
the wax heats up, it can deform,
223
00:24:35,960 --> 00:24:37,919
and the laws of physics themselves
224
00:24:37,920 --> 00:24:40,359
change the circles into hexagons?
225
00:24:40,360 --> 00:24:42,399
That's still not agreed upon,
226
00:24:42,400 --> 00:24:46,679
but what is agreed upon by the
mathematicians and the bees
227
00:24:46,680 --> 00:24:49,399
is the hexagon
is the most efficient shape.
228
00:24:49,400 --> 00:24:51,399
That just shows you.
It's a beautiful thing.
229
00:24:51,400 --> 00:24:54,759
Mathematics is
the universal language,
230
00:24:54,760 --> 00:24:57,159
and when you look at a
perfect honeycomb,
231
00:24:57,160 --> 00:25:01,679
you see a shadow of that language
of mathematics
232
00:25:01,680 --> 00:25:04,440
made real by bees.
233
00:25:10,960 --> 00:25:13,680
Perfect shapes reveal simple laws.
234
00:25:19,240 --> 00:25:21,119
Whether it's spherical planets,
235
00:25:21,120 --> 00:25:23,040
sculpted by gravity...
236
00:25:27,040 --> 00:25:29,120
...pulling us to the centre of
the Earth...
237
00:25:33,680 --> 00:25:38,040
...or the mathematically refined
efficiency of hexagonal honeycombs.
238
00:25:41,960 --> 00:25:45,160
Simple laws underpin
the shapes we can see.
239
00:25:46,320 --> 00:25:47,960
And they're universal.
240
00:25:51,400 --> 00:25:53,479
But the action of these simple laws
241
00:25:53,480 --> 00:25:56,920
seems at odds with
the complex shapes of life.
242
00:26:09,920 --> 00:26:11,879
These shallow springs are home to
243
00:26:11,880 --> 00:26:14,760
one of nature's seemingly
less elegant shapes.
244
00:26:24,040 --> 00:26:25,080
The manatee.
245
00:26:26,520 --> 00:26:28,399
Like all marine animals,
246
00:26:28,400 --> 00:26:30,919
they're free from the effects
of gravity.
247
00:26:30,920 --> 00:26:33,600
No need for strong bones
to support their weight.
248
00:26:35,280 --> 00:26:38,840
But they don't have complete freedom
from the laws of physics.
249
00:26:43,760 --> 00:26:45,079
It's winter,
250
00:26:45,080 --> 00:26:48,879
and if the water temperature here
drops below 20 degrees...
251
00:26:48,880 --> 00:26:51,319
Due to cool temperatures
Friday morning...
252
00:26:51,320 --> 00:26:53,120
...for the manatee, it's deadly.
253
00:26:54,360 --> 00:26:57,800
...very dangerous, in search of
warmer aquatic environments.
254
00:26:59,240 --> 00:27:02,880
Manatees, like this female,
are vegetarians.
255
00:27:04,520 --> 00:27:08,400
Basically, she is a 10ft long
aquatic cow with no legs.
256
00:27:09,360 --> 00:27:14,079
To stay warm, she has to consume up
to 50kg of leaves and seagrass
257
00:27:14,080 --> 00:27:15,160
every day.
258
00:27:16,120 --> 00:27:19,639
And the females here are eating
for others, too.
259
00:27:19,640 --> 00:27:22,719
This one is suckling
two young calves.
260
00:27:22,720 --> 00:27:25,000
And the weather
is only getting colder.
261
00:27:35,600 --> 00:27:36,640
Looking good.
262
00:27:41,720 --> 00:27:42,879
There's Doug.
263
00:27:42,880 --> 00:27:45,039
Doug likes it up here now.
264
00:27:45,040 --> 00:27:48,679
Researcher Wayne Hartley
is doing this morning's headcount,
265
00:27:48,680 --> 00:27:50,640
part of a manatee census.
266
00:27:55,160 --> 00:27:57,520
It's a special thing
to come to work...
267
00:27:59,320 --> 00:28:01,359
...come down in the morning,
268
00:28:01,360 --> 00:28:02,480
and it's quiet.
269
00:28:03,640 --> 00:28:05,400
The steam's coming off the water.
270
00:28:10,760 --> 00:28:14,480
I can hear the manatees out there
breathing. It's just "whoosh".
271
00:28:16,720 --> 00:28:18,719
And they are so peaceful.
272
00:28:18,720 --> 00:28:20,240
They are so calm.
273
00:28:22,480 --> 00:28:26,559
Just watching manatees has got to
be good for your blood pressure,
274
00:28:26,560 --> 00:28:28,480
and anything else that may ail you.
275
00:28:38,760 --> 00:28:41,439
Biologist Amy Tegg
is working with Wayne
276
00:28:41,440 --> 00:28:43,520
to do a health check
on the families.
277
00:28:45,320 --> 00:28:48,799
Well, he's just sort of hanging
around, checking things out.
278
00:28:48,800 --> 00:28:52,680
Manatees are very docile,
gentle creatures.
279
00:28:53,600 --> 00:28:55,359
But they are very curious.
280
00:28:55,360 --> 00:28:56,999
Anything new in their environment,
281
00:28:57,000 --> 00:28:59,199
they often like to come check out.
282
00:28:59,200 --> 00:29:01,960
So he's probably just
checking me out.
283
00:29:03,240 --> 00:29:05,080
Yeah, he's just chewing
on my flipper.
284
00:29:06,120 --> 00:29:07,960
Got 23.5 degrees Celsius.
285
00:29:09,120 --> 00:29:12,239
Manatee families are drawn in
from colder waters,
286
00:29:12,240 --> 00:29:13,800
because this is a hot spring.
287
00:29:14,840 --> 00:29:17,399
And some make it just in time.
288
00:29:17,400 --> 00:29:19,720
He is severely cold stressed.
289
00:29:21,440 --> 00:29:23,520
With the cold stress,
they don't eat.
290
00:29:24,800 --> 00:29:26,680
Their immune system shuts down.
291
00:29:27,640 --> 00:29:30,719
They're here to keep themselves
alive in the winter.
292
00:29:30,720 --> 00:29:34,040
They really require warm water.
293
00:29:38,560 --> 00:29:43,080
It might look like these animals
keep warm using blubber, like seals.
294
00:29:44,120 --> 00:29:45,799
But they're not fat.
295
00:29:45,800 --> 00:29:47,000
They're round.
296
00:29:48,160 --> 00:29:49,639
In terms of pure physics,
297
00:29:49,640 --> 00:29:52,600
the best way to stay warm
is to be a sphere.
298
00:29:57,040 --> 00:30:01,080
It has the smallest surface area
to volume ratio of any shape.
299
00:30:02,040 --> 00:30:04,440
Less area for heat to escape from.
300
00:30:06,000 --> 00:30:09,599
A beautiful example of the
naturally occurring shape
301
00:30:09,600 --> 00:30:12,160
reflecting a deeper
mathematical law.
302
00:30:13,560 --> 00:30:16,720
The manatee could well be
the most spherical mammal on earth.
303
00:30:17,920 --> 00:30:19,400
What a wonderful thing to be.
304
00:30:25,400 --> 00:30:26,840
Sorry, their breath stinks.
305
00:30:28,240 --> 00:30:31,720
To me, it smells like the inside
of a hot truck tyre.
306
00:30:36,000 --> 00:30:38,520
But, of course,
they're not perfect spheres.
307
00:30:40,520 --> 00:30:44,000
There are many other competing
factors that determine their shape.
308
00:30:44,920 --> 00:30:51,240
Like all animals, they have to live,
breathe, eat and move.
309
00:30:54,160 --> 00:30:56,680
The manatee's natural habitat
is shrinking.
310
00:30:57,640 --> 00:30:59,920
And they need to
find warmth elsewhere.
311
00:31:03,640 --> 00:31:06,039
This power station
helps provide energy
312
00:31:06,040 --> 00:31:08,759
for around nine million people,
313
00:31:08,760 --> 00:31:11,199
and in the process warms the water
314
00:31:11,200 --> 00:31:14,800
that keeps over half of Florida's
manatees alive through the winter.
315
00:31:19,560 --> 00:31:22,359
The same families
that Wayne and Amy study
316
00:31:22,360 --> 00:31:25,680
can end up here - over 300km away...
317
00:31:27,200 --> 00:31:28,639
...where their mothers and calves
318
00:31:28,640 --> 00:31:30,920
can hold on to as much heat
as possible...
319
00:31:32,120 --> 00:31:33,920
...because of their round bodies.
320
00:31:36,400 --> 00:31:39,519
To a physicist,
the perfect shape for a manatee
321
00:31:39,520 --> 00:31:42,159
would be a symmetrical sphere.
322
00:31:42,160 --> 00:31:44,320
But biology complicates things.
323
00:31:46,160 --> 00:31:48,039
Manatees can't just bob around
324
00:31:48,040 --> 00:31:50,440
waiting for food or warmth
to come to them.
325
00:31:51,960 --> 00:31:54,520
They need fins and a tail
to move around.
326
00:31:56,240 --> 00:31:59,640
Whether that is to a hot spring
or to a power station.
327
00:32:11,360 --> 00:32:16,559
The forces of nature sculpt and
restrict the shapes of all things,
328
00:32:16,560 --> 00:32:20,839
the inanimate,
like pebbles or rocks or cliffs,
329
00:32:20,840 --> 00:32:22,880
or living things.
330
00:32:25,360 --> 00:32:29,120
But of course, basic physics
is not the only force shaping life.
331
00:32:33,480 --> 00:32:35,759
Evolution, by natural selection,
332
00:32:35,760 --> 00:32:38,239
moulds living things over time
333
00:32:38,240 --> 00:32:40,279
in response to their environment
334
00:32:40,280 --> 00:32:42,920
and their interaction
with other life forms.
335
00:32:46,920 --> 00:32:49,480
And it's had billions of years
to do it.
336
00:32:51,880 --> 00:32:55,799
So you can't understand
the shape of living things
337
00:32:55,800 --> 00:32:58,320
without understanding
their evolutionary history.
338
00:33:31,600 --> 00:33:34,359
We are all the product
of our experiences,
339
00:33:34,360 --> 00:33:37,679
our history, our culture.
340
00:33:37,680 --> 00:33:40,159
Our lives
make an indelible impression
341
00:33:40,160 --> 00:33:42,320
and make us all different.
342
00:33:47,840 --> 00:33:49,840
But we are also all similar.
343
00:33:50,880 --> 00:33:53,479
Not just to each other
as human beings,
344
00:33:53,480 --> 00:33:56,959
but to countless other animals
on Earth.
345
00:33:56,960 --> 00:33:59,720
We are obviously related.
346
00:34:03,120 --> 00:34:07,240
Most obviously through the symmetry
of our bodies.
347
00:34:29,080 --> 00:34:31,679
Mrs Chae and Miss Kim
348
00:34:31,680 --> 00:34:33,959
are haenyeo, are women of the sea.
349
00:34:33,960 --> 00:34:37,120
They've grown up collecting seafood
along these shores.
350
00:34:38,400 --> 00:34:40,160
And they still do.
351
00:34:53,160 --> 00:34:55,519
The haenyeo are part of
a dying tradition.
352
00:34:55,520 --> 00:34:58,120
Not many youngsters
are interested any more.
353
00:34:59,880 --> 00:35:03,480
It's hard work,
especially if you're in your 70s.
354
00:35:31,880 --> 00:35:35,280
Right now, the women are
catching conch, or sea snails.
355
00:35:38,800 --> 00:35:40,839
It's a crucial time of year,
356
00:35:40,840 --> 00:35:43,440
when they have a chance
to make the most money.
357
00:35:55,920 --> 00:35:58,279
The tradition of freediving for food
358
00:35:58,280 --> 00:36:01,519
is part of these women's
cultural history.
359
00:36:01,520 --> 00:36:04,359
But the details
of the human form itself,
360
00:36:04,360 --> 00:36:09,439
in particular, its symmetry that
allows them to dive, swim and hunt,
361
00:36:09,440 --> 00:36:11,520
is part of their
evolutionary history.
362
00:36:50,960 --> 00:36:53,799
For Mrs Chae and Miss Kim,
363
00:36:53,800 --> 00:36:55,880
this is all about
the search for food.
364
00:36:59,640 --> 00:37:02,920
And that's where the symmetrical
structure of their bodies comes in.
365
00:37:03,880 --> 00:37:06,719
A blueprint that started
out here in the oceans
366
00:37:06,720 --> 00:37:08,920
hundreds of millions of years ago.
367
00:37:12,480 --> 00:37:15,360
Very few animals
have steered clear of it.
368
00:37:38,880 --> 00:37:43,279
Life is, and always has been,
a competition.
369
00:37:43,280 --> 00:37:45,599
In a free-floating world,
370
00:37:45,600 --> 00:37:49,600
life grew to adopt different types
of symmetry to get what it needed.
371
00:37:52,360 --> 00:37:56,039
Some animals became round,
or radially symmetric,
372
00:37:56,040 --> 00:37:59,880
organising their sensory organs
around a central axis.
373
00:38:00,920 --> 00:38:02,919
Rather than chasing down food,
374
00:38:02,920 --> 00:38:05,000
they waited for food
to come to them.
375
00:38:06,680 --> 00:38:09,919
But in order
to really go after prey,
376
00:38:09,920 --> 00:38:12,760
you need to leave
that strategy behind.
377
00:38:15,480 --> 00:38:17,680
You need to be
divided down the middle.
378
00:38:18,640 --> 00:38:22,359
That gives you two sides -
bilateral symmetry.
379
00:38:22,360 --> 00:38:24,840
Basically,
you have a left and a right.
380
00:38:28,800 --> 00:38:33,679
And you can build on this plan
with arms to grab and search
381
00:38:33,680 --> 00:38:35,280
and a head and a tail.
382
00:38:36,960 --> 00:38:39,919
All this means
you can orientate yourself
383
00:38:39,920 --> 00:38:42,400
and really target your prey.
384
00:38:50,680 --> 00:38:55,040
This body plan has been selected for
over hundreds of millions of years.
385
00:38:56,040 --> 00:38:58,120
It confers a survival advantage.
386
00:38:59,640 --> 00:39:02,439
And it turns out that
all animals with brains
387
00:39:02,440 --> 00:39:04,560
are bilaterally symmetrical.
388
00:39:09,520 --> 00:39:12,639
Bilateral symmetry
provided the agility
389
00:39:12,640 --> 00:39:15,999
that drove a spiral
of cunning and fast predators
390
00:39:16,000 --> 00:39:17,840
and skittish, speedy prey.
391
00:39:48,600 --> 00:39:53,519
The beautiful symmetry of the human
body, which we all take for granted,
392
00:39:53,520 --> 00:39:57,200
is the product of a sweeping,
majestic story...
393
00:39:58,840 --> 00:40:01,800
...stretching back to some
of the earliest life on Earth.
394
00:40:11,760 --> 00:40:15,719
So we can understand
the symmetry of organisms
395
00:40:15,720 --> 00:40:17,640
by understanding their history.
396
00:40:20,520 --> 00:40:22,079
You're essentially seeing
397
00:40:22,080 --> 00:40:24,839
the results of evolution
by natural selection
398
00:40:24,840 --> 00:40:28,720
over hundreds of millions,
even billions of years.
399
00:40:32,720 --> 00:40:35,519
But how do you understand
400
00:40:35,520 --> 00:40:38,559
the structure and symmetry
of a snowflake?
401
00:40:38,560 --> 00:40:41,239
There's no natural selection here.
402
00:40:41,240 --> 00:40:46,039
There's no DNA to record
and reproduce information.
403
00:40:46,040 --> 00:40:51,480
These things arise spontaneously
from basic laws of physics.
404
00:40:57,600 --> 00:41:02,439
The intricate beauty of a snowflake
is at first sight baffling,
405
00:41:02,440 --> 00:41:04,600
given the simplicity of their story.
406
00:41:05,720 --> 00:41:07,960
But in fact, it's a gift.
407
00:41:09,080 --> 00:41:11,359
A gift of almost nothing.
408
00:41:11,360 --> 00:41:13,439
One frozen moment
409
00:41:13,440 --> 00:41:16,839
that can reveal how the underlying
laws of nature
410
00:41:16,840 --> 00:41:19,800
can lead to seemingly
infinite complexity.
411
00:41:24,920 --> 00:41:27,559
Because snowflakes form in minutes
412
00:41:27,560 --> 00:41:30,439
and are made out of
a single ingredient,
413
00:41:30,440 --> 00:41:32,239
with strange properties
414
00:41:32,240 --> 00:41:36,119
that give rise to a vast array
of naturally occurring forms
415
00:41:36,120 --> 00:41:39,320
of all shapes, sizes and behaviours.
416
00:41:43,560 --> 00:41:45,200
Ice.
417
00:41:53,120 --> 00:41:56,120
You know, it's so mystical when
you leave in the morning in the fog.
418
00:41:57,760 --> 00:41:59,520
You're just looking around...
419
00:42:01,120 --> 00:42:04,320
...and then you see these shapes
that come out of the fog.
420
00:42:13,840 --> 00:42:15,999
They are big, big,
heavy objects.
421
00:42:16,000 --> 00:42:20,280
Far bigger than anything that
we've created floating on the sea.
422
00:42:40,840 --> 00:42:42,159
We've got to remember,
423
00:42:42,160 --> 00:42:44,359
it was an iceberg
that sailed past Newfoundland
424
00:42:44,360 --> 00:42:46,680
which ended up sinking the Titanic.
425
00:42:49,840 --> 00:42:52,280
Doug Allen is here
because it's iceberg season.
426
00:42:55,120 --> 00:42:57,559
He's part of a scientific
expedition.
427
00:42:57,560 --> 00:43:01,839
Every summer, thousands of icebergs
float south from the Arctic
428
00:43:01,840 --> 00:43:03,559
into the shipping lanes
and oilfields
429
00:43:03,560 --> 00:43:06,120
off the coast of Newfoundland.
430
00:43:08,080 --> 00:43:09,919
This team are here to help protect
431
00:43:09,920 --> 00:43:12,719
those multibillion dollar
industries,
432
00:43:12,720 --> 00:43:16,560
by trying to understand more about
where the icebergs are heading.
433
00:43:18,080 --> 00:43:21,279
The man leading the expedition
is Neil Riggs.
434
00:43:21,280 --> 00:43:23,599
So you put it back in the water
again, OK.
435
00:43:23,600 --> 00:43:25,039
And if we lose control,
436
00:43:25,040 --> 00:43:26,639
then we take it in and we secure it.
437
00:43:26,640 --> 00:43:28,800
And if that goes nowhere,
we go home.
438
00:43:31,800 --> 00:43:34,759
The big problem with icebergs
is simple...
439
00:43:34,760 --> 00:43:36,280
They float.
440
00:43:43,680 --> 00:43:48,239
Iceberg ice reflects
radar 69 times less effectively
441
00:43:48,240 --> 00:43:50,400
than a ship with the same
cross-sectional area.
442
00:43:52,760 --> 00:43:55,999
Yes, we've got some here.
443
00:43:56,000 --> 00:43:58,159
So you could be sailing along
444
00:43:58,160 --> 00:44:00,639
and doing very good seamanship,
looking at your radar
445
00:44:00,640 --> 00:44:03,319
and there's the thing
all of a sudden and you're upon it
446
00:44:03,320 --> 00:44:06,239
and it's still a massive piece
of ice relative to your ship.
447
00:44:06,240 --> 00:44:08,040
So it can make a nice little hole.
448
00:44:10,960 --> 00:44:13,559
The team will have to understand
the influence
449
00:44:13,560 --> 00:44:15,159
of a large number of variables
450
00:44:15,160 --> 00:44:18,319
if they are to distinguish between
harmless icebergs
451
00:44:18,320 --> 00:44:20,719
and dangerous ones.
452
00:44:20,720 --> 00:44:22,679
It's a complicated jigsaw.
453
00:44:22,680 --> 00:44:24,359
You could think of it
as a crime scene
454
00:44:24,360 --> 00:44:26,839
where you have
the forensic people go in
455
00:44:26,840 --> 00:44:28,439
and they pick up
little bits of clues,
456
00:44:28,440 --> 00:44:30,520
and together
you make a bigger picture.
457
00:44:31,600 --> 00:44:35,319
What I'm doing is just adding my
little piece to the overall picture
458
00:44:35,320 --> 00:44:40,040
and hopefully helping their
mathematical models to be more real.
459
00:44:41,760 --> 00:44:44,799
Doug is a specialist
cold water diver.
460
00:44:44,800 --> 00:44:48,919
It's his job to photograph
the underside of the icebergs.
461
00:44:48,920 --> 00:44:51,799
We'll go over
to some of those smaller pieces.
462
00:44:51,800 --> 00:44:53,519
OK. OK.
463
00:44:53,520 --> 00:44:56,439
Yes, Captain Manning,
we are OK to put the diver...
464
00:44:56,440 --> 00:44:59,040
Rick Stanley
is looking after safety.
465
00:45:04,560 --> 00:45:06,159
Who knows what's going to happen?
466
00:45:06,160 --> 00:45:08,279
There's so much pressure in this ice
467
00:45:08,280 --> 00:45:11,999
that it blows, it explodes.
468
00:45:12,000 --> 00:45:14,239
But there's pressure in there
469
00:45:14,240 --> 00:45:16,639
that can blow a piece of iceberg
off the ice
470
00:45:16,640 --> 00:45:18,520
probably 15 or 20 feet.
471
00:45:25,840 --> 00:45:28,439
And we were just
pottering around and suddenly,
472
00:45:28,440 --> 00:45:31,119
with no warning at all,
the whole thing split in half
473
00:45:31,120 --> 00:45:34,280
and it was almost like it was
all falling into each other.
474
00:45:42,600 --> 00:45:44,519
This might be a bit unstable.
475
00:45:44,520 --> 00:45:46,439
This is a huge berg.
476
00:45:46,440 --> 00:45:49,799
I'd rather dive around one
that wasn't falling apart.
477
00:45:49,800 --> 00:45:51,000
Yeah.
478
00:45:54,920 --> 00:45:57,359
These giant frozen mountains
479
00:45:57,360 --> 00:46:00,200
are born from
the most innocent beginnings.
480
00:46:05,320 --> 00:46:06,880
Snowflakes.
481
00:46:09,280 --> 00:46:11,039
Over thousands of years,
482
00:46:11,040 --> 00:46:13,759
they compress to form glaciers,
483
00:46:13,760 --> 00:46:17,039
that then break off
to form icebergs.
484
00:46:17,040 --> 00:46:20,160
An average one
weighs 200,000 tonnes.
485
00:46:22,880 --> 00:46:24,639
And that, give or take,
486
00:46:24,640 --> 00:46:27,479
is around 100 trillion snowflakes
487
00:46:27,480 --> 00:46:30,279
that form the structures that
the expedition is trying to model,
488
00:46:30,280 --> 00:46:33,919
using a combination of sonar robots
489
00:46:33,920 --> 00:46:35,920
and Doug's first-hand observations.
490
00:46:37,600 --> 00:46:40,879
I'll basically have a good look at
one side of the berg
491
00:46:40,880 --> 00:46:43,679
between the surface and 30 metres.
492
00:46:43,680 --> 00:46:45,119
Tell them what I saw,
493
00:46:45,120 --> 00:46:47,239
and it will mean
that they can interpret the sonar
494
00:46:47,240 --> 00:46:48,559
the data that comes back.
495
00:46:48,560 --> 00:46:51,280
They will get a better idea of it,
if I've seen it for myself.
496
00:47:20,840 --> 00:47:24,240
It's quite eerie
going down the side of the iceberg.
497
00:47:25,760 --> 00:47:29,800
You're going down into the darkness,
into the blue, into the green.
498
00:47:36,320 --> 00:47:40,119
And very occasionally there will be
this really loud thud,
499
00:47:40,120 --> 00:47:43,079
just like someone had hit you
with the flat of their hand
500
00:47:43,080 --> 00:47:45,000
in the centre of your chest...
501
00:47:46,400 --> 00:47:49,480
...where the iceberg
is banging on the bottom.
502
00:47:57,720 --> 00:47:59,919
You really don't want to go
too far down
503
00:47:59,920 --> 00:48:01,719
because there is a real danger
504
00:48:01,720 --> 00:48:04,320
of being squished
by the iceberg underneath.
505
00:48:08,920 --> 00:48:11,679
Well, you always worry when divers
are in the water.
506
00:48:11,680 --> 00:48:13,439
But iceberg diving,
507
00:48:13,440 --> 00:48:17,039
there's even more of that
anticipation and excitement
508
00:48:17,040 --> 00:48:19,840
that goes on
in the lower part of your belly.
509
00:48:28,880 --> 00:48:31,999
So you swim in and you
begin to see the details.
510
00:48:32,000 --> 00:48:36,519
You begin to realise
that this is not a flat wall of ice
511
00:48:36,520 --> 00:48:38,199
going into the depths.
512
00:48:38,200 --> 00:48:40,719
This has tiny little dimples on it.
513
00:48:40,720 --> 00:48:43,520
It almost looks like
a giant golf ball.
514
00:48:49,960 --> 00:48:52,519
These features
are added to the models,
515
00:48:52,520 --> 00:48:55,639
to understand how they affect the
way the icebergs float
516
00:48:55,640 --> 00:48:59,760
and travel over long distances
and into the shipping lanes.
517
00:49:01,560 --> 00:49:04,959
It's good to contribute to science
at a basic level like this.
518
00:49:04,960 --> 00:49:06,879
When the science is still
developing,
519
00:49:06,880 --> 00:49:09,279
to come in, take some shots,
which helps scientists,
520
00:49:09,280 --> 00:49:10,760
that's really useful.
521
00:49:16,200 --> 00:49:18,479
For all their unpredictability,
522
00:49:18,480 --> 00:49:22,200
there is regularity
in the behaviour of icebergs...
523
00:49:24,920 --> 00:49:28,640
...if you look carefully
and ask the right questions.
524
00:49:29,800 --> 00:49:32,200
Which is what science is all about.
525
00:49:38,160 --> 00:49:40,599
And the simplest question of all
526
00:49:40,600 --> 00:49:43,840
is about the most obvious part
of their behaviour.
527
00:49:46,040 --> 00:49:48,040
Why does ice float?
528
00:49:49,960 --> 00:49:51,799
That's not a naive question,
529
00:49:51,800 --> 00:49:55,960
because no other commonly occurring
solid floats on its own liquid.
530
00:49:58,080 --> 00:50:02,240
The answer lies in the structure
of the water molecule itself.
531
00:50:03,640 --> 00:50:05,439
Think of what a molecule is.
532
00:50:05,440 --> 00:50:07,919
Take a water molecule, for example.
533
00:50:07,920 --> 00:50:11,759
It's two hydrogen atoms
stuck to an oxygen atom.
534
00:50:11,760 --> 00:50:16,999
That's two hydrogen nuclei, which
have a positive electric charge,
535
00:50:17,000 --> 00:50:21,799
sticking to an oxygen nucleus, which
has a positive electric charge.
536
00:50:21,800 --> 00:50:25,239
And they're surrounded
by negatively-charged electrons.
537
00:50:25,240 --> 00:50:27,839
That's what sticks
the atoms together.
538
00:50:27,840 --> 00:50:30,479
The negatively-charged electrons
539
00:50:30,480 --> 00:50:33,919
tend to cluster around
the oxygen nucleus,
540
00:50:33,920 --> 00:50:40,639
leaving those two legs of hydrogen
slightly positively charged.
541
00:50:40,640 --> 00:50:43,439
That means that
those positive charges
542
00:50:43,440 --> 00:50:48,839
can attract other negatively-charged
ends of other water molecules.
543
00:50:48,840 --> 00:50:54,199
So an oxygen can come and orientate
itself and bond to that leg.
544
00:50:54,200 --> 00:50:57,719
On the other side, another
oxygen from another water molecule
545
00:50:57,720 --> 00:51:01,319
will be attracted to the positive
charge and bond to that leg.
546
00:51:01,320 --> 00:51:04,759
On the top, you get a hydrogen
bonding to that leg.
547
00:51:04,760 --> 00:51:07,399
So you can see
you build up a structure,
548
00:51:07,400 --> 00:51:09,159
an open crystal structure.
549
00:51:09,160 --> 00:51:12,679
A shape which is actually hexagonal.
550
00:51:12,680 --> 00:51:16,159
And it's that property,
that open structure,
551
00:51:16,160 --> 00:51:19,079
which is a reflection
of the underlying structure
552
00:51:19,080 --> 00:51:21,399
of the water molecule itself
553
00:51:21,400 --> 00:51:27,119
that leads to the solid ice
being less dense than the liquid.
554
00:51:27,120 --> 00:51:34,440
And that is why ice cubes and
icebergs float on liquid water.
555
00:51:38,080 --> 00:51:40,479
The hexagonal structure of ice
556
00:51:40,480 --> 00:51:44,240
is a shadow of the forces of nature
that hold molecules together.
557
00:51:48,920 --> 00:51:51,800
Forces that shape
every molecule of water...
558
00:51:53,880 --> 00:51:57,640
...and that create
a sixfold symmetry of snowflakes.
559
00:52:02,680 --> 00:52:05,319
You can tell
they're all the same thing.
560
00:52:05,320 --> 00:52:06,800
They're all six-sided.
561
00:52:08,120 --> 00:52:11,319
And yet,
you can also see just by eye,
562
00:52:11,320 --> 00:52:12,959
that every one is different.
563
00:52:12,960 --> 00:52:15,119
Some radically different.
564
00:52:15,120 --> 00:52:20,679
It's very difficult to imagine how
all this beauty and complexity
565
00:52:20,680 --> 00:52:25,360
could emerge spontaneously
from a few simple laws of nature.
566
00:52:30,800 --> 00:52:33,079
As snowflakes fall through the sky,
567
00:52:33,080 --> 00:52:36,560
they form and grow
around a symmetrical framework.
568
00:52:38,400 --> 00:52:41,999
So if you start with an ice crystal
569
00:52:42,000 --> 00:52:45,879
and some part of it has got
a flat bit,
570
00:52:45,880 --> 00:52:47,919
part of the hexagonal if you like,
571
00:52:47,920 --> 00:52:49,759
and some bits a bit rough,
572
00:52:49,760 --> 00:52:52,559
then water molecules
are more likely to bind
573
00:52:52,560 --> 00:52:55,239
to the rough bits
than the flat bits.
574
00:52:55,240 --> 00:52:57,519
There are basically more ways
for them,
575
00:52:57,520 --> 00:52:59,799
more sites for them to stick to.
576
00:52:59,800 --> 00:53:01,719
So that means that the rough bits
577
00:53:01,720 --> 00:53:04,759
will accumulate more molecules
than the flat bit
578
00:53:04,760 --> 00:53:07,839
and it'll build up faster
until it gets flat.
579
00:53:07,840 --> 00:53:09,599
And then it'll slow down.
580
00:53:09,600 --> 00:53:11,479
So there's a tendency
581
00:53:11,480 --> 00:53:15,239
for the underlying structure
of the ice crystals themselves
582
00:53:15,240 --> 00:53:18,600
to get echoed
into bigger and bigger units.
583
00:53:20,120 --> 00:53:22,799
Then there's a second process
called branching,
584
00:53:22,800 --> 00:53:24,799
or the branch instability.
585
00:53:24,800 --> 00:53:26,919
That happens when the snowflake
586
00:53:26,920 --> 00:53:30,439
goes into a particularly humid
region in a cloud.
587
00:53:30,440 --> 00:53:33,959
So that's a region where there are
lots of water molecules available.
588
00:53:33,960 --> 00:53:37,439
So you get a little bump
on the flat surface.
589
00:53:37,440 --> 00:53:42,759
That bump is more likely to have
water molecules bind to it,
590
00:53:42,760 --> 00:53:45,159
it's got more binding sites,
if you like.
591
00:53:45,160 --> 00:53:48,879
So it will grow quickly if there are
lots of water molecules available.
592
00:53:48,880 --> 00:53:51,279
So it will grow into a spike
593
00:53:51,280 --> 00:53:54,559
and then other bumps can appear
and they'll grow into spikes.
594
00:53:54,560 --> 00:53:57,359
So that's how
you get that star-like,
595
00:53:57,360 --> 00:53:59,680
sharp structures on snowflakes.
596
00:54:00,840 --> 00:54:05,119
But then the snowflake drifts back
into a region that's less humid,
597
00:54:05,120 --> 00:54:07,639
so there are less water molecules
available.
598
00:54:07,640 --> 00:54:10,199
Then the faceting
takes over again
599
00:54:10,200 --> 00:54:14,199
and smooth edges,
hexagonal structures start to form.
600
00:54:14,200 --> 00:54:16,279
Then it goes into a humid region
601
00:54:16,280 --> 00:54:18,800
and the branching takes over
and you get the branches.
602
00:54:27,640 --> 00:54:30,679
It's a wonderfully complex
and intricate process.
603
00:54:30,680 --> 00:54:32,999
And the thing I find
most beautiful about it
604
00:54:33,000 --> 00:54:35,479
is that when you look
at a snowflake,
605
00:54:35,480 --> 00:54:37,999
then you can read
its entire history,
606
00:54:38,000 --> 00:54:41,040
you can see its history made solid.
607
00:54:43,800 --> 00:54:48,039
Every individual snowflake
has a different history.
608
00:54:48,040 --> 00:54:51,919
Every snowflake followed a slightly
different path
609
00:54:51,920 --> 00:54:53,999
through the clouds
and onto the ground.
610
00:54:54,000 --> 00:54:59,479
And that means every snowflake
grew in a subtly different way.
611
00:54:59,480 --> 00:55:03,079
And that's why no two snowflakes
are ever alike,
612
00:55:03,080 --> 00:55:08,200
because no two paths through time
are ever alike.
613
00:55:15,360 --> 00:55:18,280
When you look at a snowflake,
you see history...
614
00:55:19,480 --> 00:55:25,120
...and the deep structure of nature
condensed into a frozen moment.
615
00:55:27,760 --> 00:55:30,320
Look how many stars
it is together!
616
00:55:31,520 --> 00:55:33,800
You can see them so clearly.
617
00:55:36,680 --> 00:55:37,959
You look.
618
00:55:37,960 --> 00:55:40,479
It is wonderful, you know,
that when you think about it,
619
00:55:40,480 --> 00:55:44,520
the whole universe, the whole of
physics is contained in a snowflake.
620
00:55:45,840 --> 00:55:49,759
To describe them, you need
all four forces of nature.
621
00:55:49,760 --> 00:55:52,039
You need gravity
622
00:55:52,040 --> 00:55:54,599
to allow the snowflake to fall down
through the clouds
623
00:55:54,600 --> 00:55:55,959
and onto the ground.
624
00:55:55,960 --> 00:56:00,639
You need electromagnetism to stick
all those water molecules together
625
00:56:00,640 --> 00:56:03,639
to form these beautiful crystals.
626
00:56:03,640 --> 00:56:05,399
You need the nuclear forces
627
00:56:05,400 --> 00:56:09,279
to stick the atomic nuclei
of oxygen together.
628
00:56:09,280 --> 00:56:13,439
And then you need to understand
about symmetry
629
00:56:13,440 --> 00:56:15,399
and symmetry breaking.
630
00:56:15,400 --> 00:56:18,879
All the fundamental ideas that
underline modern physics
631
00:56:18,880 --> 00:56:22,680
can be thought of in the journey
of a snowflake to the ground.
632
00:56:26,240 --> 00:56:29,359
Oh, look! How many stars
do you think there are?
633
00:56:29,360 --> 00:56:30,960
Oh, wow!
634
00:56:33,360 --> 00:56:37,479
Every snowflake shares the same
building blocks,
635
00:56:37,480 --> 00:56:43,719
the same basic, beautiful symmetric
forces of nature at their heart.
636
00:56:43,720 --> 00:56:46,879
But because of their histories,
because of the way they formed,
637
00:56:46,880 --> 00:56:48,439
they're all different.
638
00:56:48,440 --> 00:56:51,959
And so it is with solar systems,
so it is with planets
639
00:56:51,960 --> 00:56:53,999
and so it is with people.
640
00:56:54,000 --> 00:56:56,559
We're all made out of the same
building blocks,
641
00:56:56,560 --> 00:57:00,159
but we're all slightly
and magnificently different
642
00:57:00,160 --> 00:57:02,960
because of the history
of our formation.
643
00:57:10,000 --> 00:57:12,799
The structures we see
in the universe,
644
00:57:12,800 --> 00:57:16,799
like stars and planets and trees
and snowflakes,
645
00:57:16,800 --> 00:57:18,880
are shadows of something deeper.
646
00:57:20,640 --> 00:57:25,200
They mask an underlying beauty
and simplicity.
647
00:57:27,040 --> 00:57:32,240
But isn't it a beautiful thought
that our origin and evolution...
648
00:57:33,280 --> 00:57:37,439
...just like the structure
of a snowflake in a snowstorm,
649
00:57:37,440 --> 00:57:42,000
can be explained
by a few simple natural laws?
650
00:57:43,040 --> 00:57:46,359
And isn't it a wonderful idea
that that thought came
651
00:57:46,360 --> 00:57:49,199
from just looking
carefully at nature
652
00:57:49,200 --> 00:57:51,000
and trying to understand it?
653
00:58:04,520 --> 00:58:10,600
♪ You are my lucky star
654
00:58:12,400 --> 00:58:16,079
♪ You open heaven's portals
655
00:58:16,080 --> 00:58:20,120
♪ Here on Earth
for this poor mortal
656
00:58:21,080 --> 00:58:27,040
♪ You're my lucky star. ♪
53164
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