Y Cosmos: Y Blaned Sadwrn Y Cosmos

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-Saturn - the most beautiful planet

-in the cosmos.

-Our understanding of Saturn and

-its moons has been revolutionized.

-In this programme, we reveal the

-remarkable story of Saturn's moons.

-It's forensic.

-It's like crime scene forensics.

-We can go there

-and take measurements.

-There are clouds there

-and it rains methane.

-It's cold and there are

-methane lakes there.

-It's even possible that some

-of Saturn's moons are home to life.

-And in the future,

-they could even become our new home.

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-Saturn is huge.

-It's more than 700 times

-bigger than the earth.

-But don't let size fool you.

-Even though Saturn is big

-and very heavy...

-..it has a lower density than water.

-So if you could find a bath big

-enough and fill it with water...

-..Saturn would float.

-Its density is between

-that of air and water.

-Other planets have rings, but none

-so vast and glorious as Saturn's.

-These rings stretch out into space

-for over 66,000 miles.

-Saturn's rings are made up mostly

-of tiny particles of ice and dust.

-They seem solid

-when you look at them...

-..but our satellites have gone

-straight through them...

-..without any damage or bumps.

-The rings are made of millions

-of snowballs, or pieces of ice.

-They all orbit Saturn together.

-Some are the size of a house.

-Millions of smaller ones

-are the size of a fist.

-Racing in and around the rings

-are over 60 moons.

-They all range in size,

-from tiny snowballs...

-..to large worlds.

-And all of them

-merit study by scientists.

-We thought planets like Saturn

-were too far away...

-..for anything to happen on them.

-We thought there'd be nothing there.

-We were so wrong!

-Saturn's first shocker

-was its wild weather.

-By sending probes like Voyager

-to the planet...

-..we've discovered that Saturn

-has violent storms.

-These winds

-race through Saturn's cloud tops...

-..faster than earth's

-strongest cyclones.

-And the lightning bolts are far more

-powerful than those on earth.

-Saturn's ferocious weather

-is surprising.

-On earth, weather is driven

-by the heat energy of the sun.

-The sun warms the land,

-generating wind.

-It causes the seas to evaporate,

-creating clouds and rain.

-Saturn lies too far from the sun

-to feel the same warmth...

-..so something else must be

-creating this violent weather.

-But what?

-Our planets have been created

-from dust, gas and ice.

-The same ingredients can still be

-found today in places like Iceland.

-If you want to build

-a giant planet like Saturn...

-..this pile of raw material

-is a great visual analogue.

-There's a lot of oxygen and hydrogen

-in the universe.

-That makes water, and water ice.

-The stuff that made the solar system

-is this stuff here.

-Dirty ice, water ice, with a bit

-of rocky and metallic minerals...

-..left in there

-in the cold of space.

-From a vast cloud of gas,

-dust and ice, a star is born.

-Our star - the sun.

-The heat of the sun

-melts the ice closest to it...

-..and blows away the gas,

-leaving only rocky debris behind.

-But further out,

-icy material and gas survive.

-Once you've fired up

-that campfire...

-..what's left

-in the inner solar system...

-..is the silicate minerals you

-make a planet like the earth from.

-Away from the sun,

-where it's colder...

-..you cross the frost line

-and what's out there...

-..is still cold enough

-to maintain the ice behind.

-There's a lot of it there.

-At first, you make a solid core

-of this material.

-When you reach a critical mass...

-..you have enough gravitational

-influence to draw in...

-..some of the hydrogen and helium

-in the interplanetary cloud.

-Saturn has begun to form.

-It draws in gas...

-..and it grows bigger and bigger.

-The planet's gravity

-also begins to grow in strength...

-..and things get seriously hot.

-Even today, Saturn's core is hotter

-than the surface of the sun.

-It's this heat, rising up, which

-forms Saturn's distinct bands...

-..and drives its extreme weather.

-The planet is rotating very quickly.

-It rotates once every 10.5 hours...

-..and this creates

-Saturn's distinctive rings.

-Air can't move easily

-from north to south...

-..so it's forced sideways

-and it forms the rings we see.

-At Saturn's north pole,

-something remarkable happens.

-A stream of air that's shaped

-like a perfect hexagon.

-This hexagon on the planet's pole

-is created by waves of pressure...

-..that go up and down three times

-as they travel around the planet.

-And it's this wave that creates

-the hexagonal shape in the clouds.

-By using cameras

-mounted on spacecrafts...

-..scientists have revealed

-Saturn's wild weather.

-And these spacecrafts

-have also revealed more...

-..about the planet's secrets -

-the rings.

-When Galileo first looked at Saturn

-through a basic telescope...

-..it looked like

-the planet had ears.

-But soon after,

-lenses were improved...

-..and they discovered the

-planet had rings around it.

-Until recently, we thought it was

-the only planet which has rings.

-It's an astonishing sight to see

-Saturn with these rings around it.

-It's brilliant!

-I first saw Saturn through a large

-telescope in Cardiff.

-I really wanted my own telescope

-and I got one on my 50th birthday!

-When you see Saturn

-through a telescope...

-..and you see the rings

-around the planet...

-..it's surprising that it's so easy

-to see something so remarkable.

-From afar, the rings seem

-quiet and serene.

-But up close

-it's a very different picture...

-..as a space probe called Cassini

-has revealed.

-Images from Cassini show ice

-particles jostling for position...

-..whizzing about inside the rings.

-Some are small - others are huge.

-We didn't learn about it

-until we sent spacecrafts...

-..to interesting places

-in our solar system.

-We've seen a revolution...

-..in our understanding of Saturn

-and its moons.

-In 2004, Cassini revealed how

-amazing these moons actually are.

-The moons

-are all different shapes and sizes.

-Some are made of rock, others from

-gases, or a combination of the two.

-But each one

-has its own unique properties.

-Sometimes, some of Saturn's

-icy moons break up...

-..adding new material to the rings.

-By looking at how the rings

-constantly change...

-..scientists are able to solve

-some of the secrets of the cosmos.

-All the planets

-in our solar system...

-..evolved from a disk of dust

-and gas 4.5 billion years ago.

-Saturn's rings give us a glimpse of

-how our planet system was formed.

-The rings around Saturn...

-..are similar to conditions in

-the early days of our solar system.

-When the planets were being created,

-there was a disc of matter...

-..similar to the rings

-around Saturn today.

-Cassini shows structures forming

-spontaneously inside the rings.

-One of the problems with trying to

-work out how planets were formed...

-..was what caused the dust

-to start clumping together.

-What we see by looking at Saturn's

-rings is it happens spontaneously.

-As they grow, the effect of gravity

-becomes more prominent.

-That's what controls events.

-Planets form.

-The more planets form,

-the more material is mopped up.

-As they collect more material,

-they clear a path.

-The telescope sees curious

-structures within the rings.

-The particles collide with each

-other and create different patterns.

-Perhaps similar forces

-influenced the earth's formation.

-Saturn's rings also show us

-why planets stop growing.

-A moon called Pan sits near

-the middle of one of Saturn's rings.

-Pan should be huge

-with so much ice around it.

-But it isn't.

-Pan is a very odd-looking moon.

-It's like two saucers back to back.

-It looks like a flying saucer!

-Within Saturn's rings, there are

-areas where a path has been cleared.

-Sometimes, this is caused

-by a small moon...

-..mopping up matter around it

-to clear a path for itself.

-Rather than pull material in,

-Pan appears to push it away.

-This may explain why multiple

-planets form around stars...

-..instead of single giant planets.

-Of all Cassini's discoveries...

-..the most important

-is also the most surprising.

-A moon that may be home to life.

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-We've been studying our moon

-for centuries.

-Every furrow and every crater

-has been carefully studied.

-We know there is no life

-on our moon.

-But what about other moons

-in the Cosmos? Are they dead too?

-It's fair to say that nobody

-expected much from Saturn's moons.

-They're too far from the sun.

-They're just snowballs

-covered in a thick layer of ice.

-We can now send spacecrafts

-like Cassini to these places.

-It's remarkable that developments

-in optics and microelectronics...

-..and the fact we can send probes

-to space is unbelievable.

-At first glance, Saturn's moons bear

-striking similarities to our own.

-Moons like Rhea and Dione.

-But there's one that reminds us

-of the Star Wars film.

-One tiny moon called Mimas looks

-like the Death Star from Star Wars.

-That huge crater...

-..was probably created

-by a collision in the distant past.

-It wasn't enough of an impact

-to destroy Mimas...

-..but it did leave a massive hole

-on its surface.

-Other moons are more dramatic, like

-Iapetus - the moon with two faces.

-One hemisphere of Iapetus

-is extremely white...

-..and its brightness

-seems to reflect any light.

-But the other side is dark,

-like soot.

-Every one of Saturn's moons

-has a story.

-Take Enceladus - a small ice moon.

-Ten years ago,

-nobody paid it any attention.

-But that's all changed

-and this is why.

-Enceladus orbits inside Saturn's

-outermost ring the E-ring.

-This ring puzzled scientists.

-How could a ring so broad

-hold itself together?

-Enceladus sits right in the middle

-of the E-ring.

-A few scientists...

-..suggested that Enceladus was

-ejecting water and ice into space.

-This would explain why the E-ring

-It turns out they were right.

-Ten years ago, Cassini captured

-an astonishing sight.

-Hundreds of geysers

-shooting water into space.

-As Enceladus orbits Saturn...

-..these geysers create

-a shimmering halo around the planet.

-This is the E-ring.

-This water also interacts

-with Saturn's magnetic field...

-..creating auroras

-above the planet's poles.

-How can geysers exist on

-a frozen moon so far from the sun?

-On earth, geysers form

-in highly volcanic places.

-Enceladus, so small and so far from

-the sun, should be cold and dead.

-What heats it is Saturn's gravity.

-The source of the heat on Enceladus

-is the eccentric orbit of that moon.

-Sometimes it's a little closer

-to Saturn.

-Sometimes it's further away.

-That heating on Enceladus from that

-kneading gravitationally...

-..making the moon stretch and pull

-is what warms the interior...

-..causing the activity on Enceladus

-that we see today.

-Saturn pushes and pulls Enceladus.

-The moon's core moves...

-..and creates heat.

-The heat melts the ice around it,

-creating vast subsurface lakes.

-This water jets out

-through cracks in the surface ice.

-On earth, where there's liquid water

-there's life.

-Is the same true on Enceladus?

-There are lakes there,

-under the surface.

-There is water and the temperature

-is good, so can it harbour life?

-We sent Cassini

-to fly over these cracks...

-..where the water was rushing out.

-Scientists hoped to find chemicals

-like ammonia and salts in the water.

-They are the building blocks

-of life.

-They weren't disappointed.

-When Cassini took a closer look

-at Enceladus...

-..it found everything that is needed

-to sustain life.

-Carbon, nitrogen, hydrogen

-and liquid water.

-This was big news

-in the science world.

-Could life exist on Enceladus?

-To find out, scientists hope to send

-more spacecrafts to collect samples.

-It's like crime scene forensics.

-We can go there, take measurements

-and find out what all this means.

-We have discovered so many

-amazing things about that moon.

-I think a detailed reconnaissance

-follow-up there would be in order.

-Not just an orbiter.

-I would like to land there.

-I would like to see

-the source of those geysers...

-..and understand

-how close to the surface...

-..is the water

-that feeds the geysers?

-Realizing that Enceladus may harbour

-life, scientists want to go there.

-But there's another moon

-vying for their attention.

-Titan - Saturn's largest moon.

-Some scientists believe they have

-proof that alien life exists here.

-Beyond Enceladus,

-everyone is now looking at Titan...

-..as a moon that could sustain life.

-More than 60 moons

-orbit the planet Saturn...

-..but one dwarfs them all.

-Titan is a colossus.

-A thick orange haze

-hides the moon's surface.

-And when the Cassini mission first

-peered beneath the orange mist...

-..it revealed a very strange world.

-Titan is very interesting.

-It's very cold here.

-It's about ten times further away

-from the sun than earth.

-Titan has mountains,

-lakes and rivers.

-But instead of water,

-the rivers flow with methane.

-What you have is methane and ethane,

-just like the gas we use at home.

-There are clouds there

-and it rains liquid methane.

-It's incredibly cold here.

-You even have lakes of methane.

-Methane takes the form of a liquid

-on Titan's surface.

-Methane can sustain life, so there's

-a lot of scientific interest.

-And like earth, Titan has a thick,

-nitrogen-rich atmosphere.

-But instead of the oxygen

-we breathe...

-..Titan's air is spiked

-with carbon-rich molecules...

-..that stain it a dull orange.

-Cassini passed through the

-top layers of Titan's atmosphere...

-..taking measurements

-of this orange mist.

-It's full of molecules similar to

-what we call pollution on earth.

-The orange hue is the effect of

-the sun's light on these chemicals.

-Titan's complex cocktail

-of chemicals puzzles scientists.

-Especially the methane gas.

-Titan's orange haze

-should have lifted - but it hasn't.

-Something must be replenishing

-the orange smog.

-But what?

-To answer this,

-Cassini released a special probe...

-..through Titan's clouds.

-As the Huygens Lander parachuted

-through the clouds, it took photos.

-The images are incredible.

-We expected to see

-exciting photographs...

-..but when they were sent back in

-January 2005, they were fantastic.

-The landscape seemed to have

-been shaped by liquid.

-But that liquid was long gone.

-Huygens landed in a spot almost

-identical to what we're standing on.

-If we look all around, we can see

-this bleak, barren landscape.

-Pebbles and cobbles

-were rounded and smooth.

-They came through river channels.

-We see plenty of those

-at the Huygens landing site.

-We also see lots of sand.

-Huygens landed in a huge desert.

-It stretches all the way

-around Titan's equator...

-..with sand-like dunes, sculpted

-by the wind like they are on earth.

-So where were

-all the lakes of liquid methane?

-They had to be at the moon's poles.

-Cassini went to look.

-One of the instruments

-on Cassini is a radar gun.

-It shoots radar waves at Titan

-which are reflected back.

-After two years of searching,

-Cassini found the lakes.

-One of the things it found was

-near the north pole of Titan...

-..were regions

-that were not reflecting radar.

-That sounds a lot like liquid.

-Liquid absorbs that energy

-and doesn't reflect it back.

-Later observations clinched it.

-Some regions of Titan

-are very smooth...

-..and we mapped lake-like

-shapes too.

-It's likely that a liquid created

-these lakes on the moon's surface.

-Lakes like this one in California...

-..with a familiar landscape

-to ours, on earth.

-If we were sitting on the margins

-of Kraken Mare...

-..the largest sea we see on Titan...

-..we'd probably see

-something similar to this landscape.

-We'd look out

-across a fairly calm surface.

-We think the winds

-are not very strong on Titan...

-..so we'd have a calm lake

-of methane and ethane.

-In the distance,

-we'd see hills and mountains...

-..that formed probably

-through tectonic processes...

-..in much the same way

-that mountains are built on earth.

-Except on Titan it's so cold that

-volcanoes spew water, not lava...

-..and the mountains and lake basins

-are solid ice.

-Scientists thought that methane

-evaporating from these lakes...

-..generated Titan's smog.

-But that wasn't the case

-according to Cassini's measurements.

-Scientists were stumped.

-The lakes were somehow

-being refilled.

-Scientist, Jani Radebough believes

-these rocky deposits called tufa...

-..offer one possible solution.

-They are formed

-when two water types react.

-This is very exciting.

-It could be a clue

-to the missing methane on Titan.

-It's rock formed from the chemicals

-contained in two fluids.

-Water emerging at the margin of the

-lake interacts with lake water...

-..which has a different chemistry.

-The dissolved chemicals combine with

-each other and create this rock.

-Radar images of Titan's largest lake

-reveal rocky structures...

-..which look just like tufa.

-Titan's tufa could be evidence

-of a layer of liquid methane...

-..that rises in springs

-to feed its lakes.

-Just like they do here,

-in California.

-When those methane springs come in,

-they interact with the lakes...

-..and rock precipitates out.

-We see organic rocks

-dotting the margins of the lakes...

-..and almost certainly

-methane bubbles up...

-..and emerges

-at the margins of the lake.

-If this is true, the moon's lakes

-create all the orange smog.

-And scientists are a step closer

-to solving Titan's mysteries.

-Titan is exciting.

-A world that looks familiar to us.

-And for the first time ever...

-..scientists believe

-they may have found life here.

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-Saturn.

-It may look peaceful and serene

-but this is an exciting planet.

-It has massive storms.

-The rings constantly evolve.

-But now Saturn's moons

-are attracting all the attention.

-There are mountains,

-lakes and rivers here.

-And now, on Titan,

-Saturn's largest moon...

-..scientists may have uncovered...

-..the first evidence

-of extraterrestrial life.

-Scientists believe that life can

-be found in Titan liquid methane.

-Unlike here on earth...

-..Titan is so cold,

-creatures would look very different.

-If life could exist here,

-it could still be there today.

-Not intelligent life.

-I don't think

-they're hiding from us!

-We're talking about

-simple life forms.

-When we go to another world...

-..we look for bacteria

-which we assume is small.

-You could ask the question

-why are bacteria so small?

-I think the answer is

-because they live in water.

-Unlike on earth, it's possible that

-bacteria on Titan would be bigger.

-On Titan, the liquid

-is liquid methane, liquid ethane.

-Very different from water.

-There's no reason an organism

-should be small. It should be huge.

-Chris McKay believes that Titan's

-lakes are home to bacteria...

-..the size of sheets of newspaper.

-If there's life on Titan

-living in liquid methane...

-..you won't need a microscope

-to see it - you'll need a yardstick.

-The opportunity

-to prove that theory came...

-..when the Cassini spacecraft

-released the Huygens probe...

-..through Titan's atmosphere.

-Simple life forms must eat something

-to survive. But what?

-As Huygens was on its way to Titan,

-I'm in a hotel writing a paper...

-..saying, hey,

-what if there's life on Titan?

-What would it eat?

-How would we detect it?

-How would this probe flying

-through the atmosphere detect it?

-The day Huygens landed, I submitted

-this paper to the journal...

-..predicting that if there was life

-on Titan it would eat hydrogen.

-The probe could measure

-depletion in hydrogen...

-..so let's look for hydrogen.

-Huygens travels

-through Titan's atmosphere...

-..sampling the gases as it goes.

-The upper atmosphere

-has plenty of hydrogen.

-So do the middle layers.

-But at ground level, there's

-a drop-off in hydrogen levels.

-Something, or perhaps someone,

-was using it up.

-When I heard the report of depletion

-of hydrogen, my heart raced.

-If this is hard data

-for the depletion of hydrogen...

-..I can't imagine any other way

-besides biology to explain that.

-It's exciting in that it's

-consistent with what we predicted...

-..but we have to wait

-for this to be confirmed...

-..by other calculations,

-by direct measurements and so on.

-McKay's theory is very exciting.

-It's supported by some evidence.

-The drop in levels of hydrogen

-support his theory to some extent.

-Could any life survive the harsh

-conditions on Titan's surface?

-We need more evidence.

-Scientists need more proof.

-Many want to return to Titan with

-more equipment to collect samples.

-There's much more

-to learn about Titan.

-The findings from Cassini and

-Huygens merely scratch the surface.

-There was talk of sending

-a small boat to land on the lakes...

-..and take samples of the liquid...

-..to see if the lakes and the rain

-are similar to what we see on earth.

-Huygens lasted for just an hour

-once it landed on Titan.

-Compare that to robotic probes

-like Spirit and Opportunity...

-..which spent years

-sending back these images of Mars.

-Some scientists want to send winged

-drones to discover more about Titan.

-We can do it right now.

-We have the technology to send

-an aeroplane to Titan this minute.

-Unmanned aerial vehicle technology

-has come up in the last decade.

-We use it all around the world.

-Because of Titan's thick atmosphere,

-it's an easy place to do this.

-We're ready right now.

-Are we on the cusp of discovering

-whether alien life exists?

-When I teach first year

-biochemistry students...

-..I tell them that

-before they leave university...

-..we may have evidence which

-takes us that one step closer...

-..and we can say that

-alien life exists.

-Images from spacecraft like Cassini

-offer a remarkable glimpse...

-..of Enceladus and Titan.

-Perhaps, one day,

-we could travel to these moons...

-..and we could even live there.

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-Saturn is a long distance

-away from earth.

-Yet in the future, perhaps humans

-will live and work here.

-That's because it has a special gas

-called Helium-3.

-Helium-3 is a promising candidate

-for producing energy.

-There's an almost endless

-energy supply there.

-The earth's gravity

-can't hold on to Helium-3...

-..but the large planets like Saturn

-and Jupiter have a lot of Helium-3.

-Enough perhaps to quench our thirst

-for fuel for millions of years.

-Helium-3 may replace oil

-as the fuel of the future.

-Helium-3 produces energy

-through the process of fusion.

-When two atoms are crushed together,

-they fuse...

-..releasing a burst of pure energy.

-Best of all, it doesn't release

-any harmful radiation waste either.

-The only trouble with Helium-3...

-..is that there's precious little

-to be found on earth.

-One place where you can find

-Helium-3 is Saturn.

-So in centuries to come,

-maybe we'll travel to Saturn...

-..to harvest Helium-3

-from the planet's atmosphere.

-It's a very exciting idea.

-Saturn and Jupiter

-have plenty of Helium-3.

-It'll be difficult

-to extract Helium-3 from Jupiter...

-..due to the planet's huge gravity.

-Neptune and Uranus

-are too far away to be practical.

-That leaves Saturn.

-Some scientists

-imagine winged drones...

-..flying through

-the upper atmosphere of Saturn...

-..scooping up the Helium-3.

-Where should we process

-this superfuel?

-The ideal base would be Titan.

-In centuries to come, when we travel

-to Saturn to harvest Helium-3...

-..Titan seems to be the

-most obvious place to live and work.

-Even though it's incredibly cold...

-..there's enough

-atmospheric pressure...

-..to allow domed villages

-to be erected.

-What's interesting about Titan

-is that its atmospheric pressure...

-..is similar

-to what we have on earth.

-Because Titan's gravity is also

-similar to that of earth...

-..it's one of the best places in our

-solar system to support human life.

-We could build a processing station

-on Titan and harvest the Helium-3.

-For those people living on Titan...

-..everyday life

-would be somewhat different.

-Titan has a very thick atmosphere,

-similar to conditions on earth.

-But the moon is smaller than earth,

-so gravity is weaker.

-If you jumped up

-and flapped your arms...

-..you could lift yourself

-off the surface.

-Not fly as such,

-but you could float a little.

-If we did use Helium-3

-as the fuel of the future...

-..a new generation

-of space travel would begin.

-Travelling to Mars and Jupiter

-would take months, not years.

-Once there's a commercial reason

-for going, not just pure science...

-..people will invest heavily in it.

-We're already

-on the verge of space tourism...

-..with Virgin Galactic hoping

-to launch within around five years.

-At first, only wealthy people

-will be able to afford it...

-..but that was true of flying

-in the 1950s.

-The only people who could afford

-to fly were the rich jet set.

-I'd like to visit Enceladus.

-I would travel to its south pole...

-..where all that water and ice

-is sprayed into space.

-It must be an amazing sight...

-..standing at the edge of

-one of those huge ridges of ice...

-..and see the gas rise,

-then fall as snow all around us.

-It would be

-an amazing place to visit.

-I'd like to go to Enceladus

-to see Saturn's rings close up.

-Standing so close to them

-that the rings fill the sky.

-That's where I would choose to go.

-Until fairly recently,

-we knew very little about Saturn.

-But now, some of the planet's

-secrets have been revealed.

-It's an exciting place that may even

-harbour life itself.

-Someday soon,

-perhaps we can visit there...

-..and see the cosmos

-from a new perspective.

-S4C subtitles by Eirlys A Jones

-.