Solar.System.2024.S01E04.1080p.BluRay.x264-DRCOX_track3_[eng] Subtitles

00:00:06,80 --> 00:00:08,(WIND WHISTLES)

00:00:26,560 --> 00:00:29,If | asked you,
"What is a planet made of?"

00:00:30,00 --> 00:00:34,then you'd probably say,
"Well, rocks and iron."

00:00:37,840 --> 00:00:39,And for the planets
of the inner solar system,

00:00:39,880 --> 00:00:44,like Earth, close to the heat
of the sun, you'd be right.

00:00:48,400 --> 00:00:51,But if you head out
into the frozen outer reaches

00:00:51,480 --> 00:00:52,of the solar system,

00:00:52,840 --> 00:00:56,then even the gases
that make up our atmosphere,

00:00:56,160 --> 00:01:00,so nitrogen and carbon dioxide
and, of course, water

00:01:00,160 --> 00:01:01,are all frozen solid.

00:01:03,840 --> 00:01:06,And the planets and moons
out there,

00:01:06,280 --> 00:01:08,the mountains and glaciers,

00:01:08,360 --> 00:01:11,and even the crust
of the worlds themselves,

00:01:11,880 --> 00:01:13,are made of that -

00:01:13,800 --> 00:01:17,solid, frozen, pristine ice.

00:01:19,480 --> 00:01:21,Ice that,
in the extreme conditions

00:01:21,960 --> 00:01:23,we find beyond Earth,

00:01:23,840 --> 00:01:27,behaves in ways
we never imagined possible.

00:01:33,880 --> 00:01:36,As we've explored
the solar system,

00:01:36,280 --> 00:01:40,our spacecraft have encountered
moons torn apart...

00:01:41,720 --> 00:01:45,...by great canyons
of shifting ice...

00:01:49,440 --> 00:01:52,... dwarf planets
where mountains of solid ice

00:01:53,00 --> 00:01:54,float across the surface...

00:01:58,200 --> 00:02:01,...worlds where ice appears
to cover one face...

00:02:03,360 --> 00:02:05,...but leaves the other
entirely alone.

00:02:11,600 --> 00:02:15,And elsewhere, alien aurora
hang above the clouds,

00:02:15,480 --> 00:02:19,all thanks to a strange,
newly discovered form of ice.

00:02:25,520 --> 00:02:27,Even here, on Earth,

00:02:27,640 --> 00:02:32,the behaviour of something
as simple as ice has had,

00:02:32,360 --> 00:02:34,we think,
profound consequences.

00:02:34,680 --> 00:02:38,Because without ice's
counterintuitive behaviour,

00:02:38,840 --> 00:02:42,life on our planet
may not have survived.

00:03:11,640 --> 00:03:14,We begin our journey
to the ice worlds

00:03:14,440 --> 00:03:17,at the freezing edge
of the solar system.

00:03:34,600 --> 00:03:38,Out here,
the sun Is so far away,

00:03:38,280 --> 00:03:40,it resembles just another star.

00:03:47,40 --> 00:03:48,Pluto is so remote

00:03:48,600 --> 00:03:51,that it was only in July
00:03:51,480 --> 00:03:55,that we had our first and,
to date, only close encounter.

00:04:01,280 --> 00:04:03,As it flew by,
the New Horizons spacecraft

00:04:04,00 --> 00:04:06,sent back
the first close-up images

00:04:06,520 --> 00:04:08,of this mysterious
frozen world.

00:04:17,800 --> 00:04:20,It discovered
a great heart-shaped plain

00:04:20,440 --> 00:04:22,1,000km across

00:04:22,600 --> 00:04:24,that dominates one face.

00:04:36,560 --> 00:04:38,Around the edge of this plain,

00:04:38,440 --> 00:04:43,mountains made of solid ice
tower over Pluto's surface.

00:04:52,120 --> 00:04:54,And amongst its rugged uplands,

00:04:54,640 --> 00:04:56,ice was detected in a form

00:04:56,760 --> 00:04:59,no-one ever expected to see
on Pluto.

00:05:05,40 --> 00:05:06,Glaciers.

00:05:08,480 --> 00:05:12,Flowing rivers of ice
on a world so far away,

00:05:12,240 --> 00:05:15,we expected
nothing would be moving.

00:05:17,440 --> 00:05:19,That's because
the temperature here

00:05:19,640 --> 00:05:24,is only 40 degrees Celsius or
so away from absolute zero...

00:05:25,920 --> 00:05:28,...a temperature
at which nothing should move.

00:05:33,80 --> 00:05:36,And yet New Horizons
discovered regions of Pluto

00:05:36,440 --> 00:05:38,that for all the world

00:05:38,240 --> 00:05:41,look like the frozen reaches
of our planet.

00:06:05,520 --> 00:06:07,So when you fly here
over the years,

00:06:07,560 --> 00:06:08,how much does it change?

00:06:09,80 --> 00:06:10,It changes every day.

00:06:10,240 --> 00:06:11,- Yeah?
- Yeah.

00:06:13,520 --> 00:06:15,The shape of the glaciers
change.

00:06:16,920 --> 00:06:18,It's never the same.

00:06:21,480 --> 00:06:24,I'm just imagining flying
over Pluto, actually...

00:06:24,360 --> 00:06:25,(CHUCKLES)

00:06:25,560 --> 00:06:27,...beCause
it looks remarkably similar.

00:06:27,960 --> 00:06:29,Really?

00:06:31,120 --> 00:06:34,- What is the topography like?
- It's like this.

00:06:34,240 --> 00:06:36,Same topography,
same mountain heights.

00:06:36,880 --> 00:06:38,LEIGHAN: That's incredible!

00:06:46,640 --> 00:06:49,PROF COX: The discovery of
Pluto's dynamic icy landscapes

00:06:50,00 --> 00:06:51,came as a huge shock.

00:06:54,480 --> 00:06:57,It forced us
to rethink our understanding

00:06:57,240 --> 00:06:59,of this so-called dwarf planet.

00:07:00,960 --> 00:07:02,LEIGHAN:
We're coming in for landing,

00:07:02,480 --> 00:07:05,so I'll just be talking
to the airplane and not you.

00:07:05,360 --> 00:07:06,PROF COxX: | respect
that choice.

00:07:06,920 --> 00:07:07,(LEIGHAN LAUGHS)

00:07:07,960 --> 00:07:11,I've had a lot of landings,
but none quite like this.

00:07:12,120 --> 00:07:13,In fact, none like this at all.

00:07:14,880 --> 00:07:18,It's the world's
most beautiful runway!

00:07:24,480 --> 00:07:27,LEIGHAN: Welcome
to the glacier, you guys!

00:07:27,600 --> 00:07:29,(PROPELLER SLOWS)

00:07:29,960 --> 00:07:31,(WIND WHISTLES)

00:07:38,200 --> 00:07:39,Wow!

00:07:41,560 --> 00:07:43,You know, when we arrived,

00:07:43,760 --> 00:07:45,they said,
"Oh, it's zero degrees,"

00:07:45,800 --> 00:07:49,and | thought, "That's great.
Zero degrees, it's warm."

00:07:49,200 --> 00:07:51,Fahrenheit.
Zero degrees Fahrenheit.

00:07:52,00 --> 00:07:54,It's about minus 20 up here.

00:07:54,160 --> 00:07:55,It's just...

00:07:55,440 --> 00:07:57,And you g***t a real sense
actually, coming in,

00:07:58,40 --> 00:08:00,of...it looks frigid
and frozen,

00:08:00,320 --> 00:08:03,you know, unmoving, unchanging,

00:08:03,160 --> 00:08:04,but it's so dynamic.

00:08:04,760 --> 00:08:07,You can feel it in the wind
as you land.

00:08:07,360 --> 00:08:09,And then,
you know, you can see...

00:08:09,720 --> 00:08:12,...you can see the way
that everything flows.

00:08:19,240 --> 00:08:21,Just look at that glacier.

00:08:22,360 --> 00:08:26,You can almost feel
or see it moving.

00:08:26,160 --> 00:08:29,It looks like
a slow-motion river,

00:08:29,160 --> 00:08:31,and indeed it is moving.

00:08:31,120 --> 00:08:33,It does flow very, very slowly.

00:08:35,680 --> 00:08:36,And the reason

00:08:36,840 --> 00:08:39,this great mass can grind
its way down the valley

00:08:39,640 --> 00:08:42,is because of the unique
properties of the ice

00:08:42,840 --> 00:08:44,from which it's made.

00:08:48,960 --> 00:08:52,That bright-blue ice
certainly looks solid.

00:08:52,640 --> 00:08:54,Immovable.

00:08:54,160 --> 00:08:56,It's formed by pressure.

00:08:56,680 --> 00:08:59,So these snowflakes
are falling down

00:08:59,280 --> 00:09:02,onto the top of the glacier,
and over time they build up,

00:09:02,320 --> 00:09:04,and their weight presses down,

00:09:04,120 --> 00:09:05,increasing the pressure,

00:09:05,840 --> 00:09:09,and you get that particular
crystalline structure of ice,

00:09:09,440 --> 00:09:12,which looks transparent
and blue.

00:09:13,440 --> 00:09:15,But actually, at those
pressures and temperatures,

00:09:15,520 --> 00:09:17,it's not completely solid.

00:09:17,160 --> 00:09:19,The crystals are
sort of arranged in planes,

00:09:19,920 --> 00:09:22,a little bit
like a deck of cards.

00:09:22,160 --> 00:09:24,And that means
that as gravity is acting,

00:09:24,720 --> 00:09:26,trying to slide
this whole thing

00:09:26,760 --> 00:09:28,down the valley.

00:09:28,200 --> 00:09:32,those planes can slip
and slide over each other,

00:09:32,120 --> 00:09:35,and that allows
the whole glacier to move.

00:09:35,400 --> 00:09:38,You can also get liquid water
between the rock and the ice,

00:09:38,400 --> 00:09:40,and that sort of lubricates
the glacier,

00:09:40,440 --> 00:09:42,and that allows it
to slip as well.

00:09:42,440 --> 00:09:45,So although this looks fixed
and immovable,

00:09:45,880 --> 00:09:48,at the conditions
we find on Earth,

00:09:48,480 --> 00:09:52,this can almost behave
like a...like a fluid,

00:09:52,320 --> 00:09:57,sort of sliding very slowly
and deforming down the valley.

00:10:07,00 --> 00:10:11,Glaciers were the last things
we expected to see on Pluto.

00:10:11,320 --> 00:10:14,It's so cold here
that we'd expect

00:10:14,480 --> 00:10:17,the ice crystals
to be too brittle to flow.

00:10:20,600 --> 00:10:24,Nothing should slip,
nothing should slide.

00:10:29,360 --> 00:10:32,Yet that's precisely
what these glaciers are doing.

00:10:37,520 --> 00:10:40,So if they can't be made
of water ice,

00:10:40,320 --> 00:10:42,what are they made of?

00:10:54,200 --> 00:10:56,As New...