Y Cosmos: Y Blaned Iau Y Cosmos
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-* | 0:00:00 | 0:00:00 | |
-Jupiter. | 0:00:01 | 0:00:03 | |
-The biggest and most important -of all the planets. | 0:00:04 | 0:00:08 | |
-All the planets in the solar system -would fit into Jupiter. | 0:00:09 | 0:00:13 | |
-Without Jupiter, -we would not be here today. | 0:00:13 | 0:00:16 | |
-It controls -everything that surrounds us. | 0:00:18 | 0:00:22 | |
-Jupiter's huge effect on our solar -system can be seen even today. | 0:00:22 | 0:00:27 | |
-In this programme, we discover why -life on earth relies on this planet. | 0:00:28 | 0:00:33 | |
-Jupiter is the shepherd -of our solar system. | 0:00:33 | 0:00:38 | |
-We reveal -Jupiter's biggest secrets... | 0:00:39 | 0:00:41 | |
-..and ask if this is the best place -to find alien life in the cosmos. | 0:00:42 | 0:00:46 | |
-If we had to name the places -where alien life is most possible... | 0:00:48 | 0:00:52 | |
-..Jupiter would be -at the top of that list. | 0:00:54 | 0:00:57 | |
-Jupiter. | 0:01:15 | 0:01:17 | |
-Named after the Roman king -of the gods - the god of the sky. | 0:01:27 | 0:01:31 | |
-If I looked at our solar system -from afar, I wouldn't see the earth. | 0:01:34 | 0:01:39 | |
-It's too small. | 0:01:39 | 0:01:40 | |
-I would see our sun. | 0:01:40 | 0:01:42 | |
-Jupiter would probably be -the only visible planet. | 0:01:43 | 0:01:46 | |
-This vast planet has had a huge -influence on our solar system. | 0:01:54 | 0:01:59 | |
-But despite its size, we know very -little about the planet itself. | 0:02:03 | 0:02:08 | |
-In the Roman myth... | 0:02:10 | 0:02:12 | |
-..Jupiter drew a veil of clouds -around him to hide his mischief. | 0:02:13 | 0:02:17 | |
-That, to some extent, is what's -happened when we look at Jupiter. | 0:02:17 | 0:02:21 | |
-We're seeing not the surface of -a planet but the edge of a cloud. | 0:02:22 | 0:02:26 | |
-It has no surface. | 0:02:27 | 0:02:29 | |
-You can't stand on it, -not even in a space suit. | 0:02:29 | 0:02:32 | |
-It's all gas. | 0:02:33 | 0:02:35 | |
-This shroud of gas -hides Jupiter's deepest secrets. | 0:02:38 | 0:02:41 | |
-What lies behind the clouds -and the beautiful bands of colour? | 0:02:43 | 0:02:48 | |
-It's a mystery. | 0:02:49 | 0:02:51 | |
-But we do know that -what's happening inside Jupiter... | 0:02:54 | 0:02:58 | |
-..gives the planet its power. | 0:02:58 | 0:03:00 | |
-One of the big mysteries of Jupiter -is what is its core? | 0:03:01 | 0:03:04 | |
-It's something we don't know yet. | 0:03:05 | 0:03:07 | |
-What we do know is that the planet's -atmosphere is very dangerous. | 0:03:09 | 0:03:13 | |
-The atmosphere is so thick... | 0:03:15 | 0:03:17 | |
-..the atmospheric pressure -at Jupiter's core... | 0:03:19 | 0:03:23 | |
-..would be thousands of times -greater than earth's atmosphere. | 0:03:23 | 0:03:28 | |
-Travelling in a jet plane from the -cloud tops to the planet's centre... | 0:03:33 | 0:03:38 | |
-..would take three days. | 0:03:38 | 0:03:40 | |
-The descent would be difficult, -dangerous and maybe impossible. | 0:03:41 | 0:03:46 | |
-We know that from experience. | 0:03:50 | 0:03:52 | |
-The Galileo spacecraft... | 0:03:53 | 0:03:55 | |
-..dropped a probe into -Jupiter's atmosphere 20 years ago. | 0:03:55 | 0:03:59 | |
-The Galileo spacecraft orbited -Jupiter and its moons for years. | 0:04:03 | 0:04:08 | |
-At the end of its life... | 0:04:09 | 0:04:10 | |
-..they decided to send a probe -into the atmosphere. | 0:04:10 | 0:04:14 | |
-The probe travels through the clouds -at speeds of 106,000 miles per hour. | 0:04:18 | 0:04:24 | |
-Jupiter is so big and dense, -gravity is very strong. | 0:04:28 | 0:04:33 | |
-Before hitting the clouds... | 0:04:34 | 0:04:36 | |
-..the probe accelerated -to exceptionally high speeds. | 0:04:37 | 0:04:41 | |
-When it hit the atmosphere... | 0:04:43 | 0:04:45 | |
-..it had to be very dense -to decelerate... | 0:04:45 | 0:04:48 | |
-..and lose the immense heat -that was created outside the probe. | 0:04:48 | 0:04:53 | |
-The Galileo probe reached pressure -levels much higher than the earth... | 0:04:54 | 0:04:59 | |
-..after entering the first -tiny percentage of the atmosphere. | 0:05:00 | 0:05:04 | |
-On its journey through the clouds, -the probe's sensors reveal... | 0:05:11 | 0:05:15 | |
-..that hydrogen makes up -90% of Jupiter's atmosphere. | 0:05:16 | 0:05:20 | |
-It's a fierce place. | 0:05:23 | 0:05:24 | |
-Temperatures soar -to over 300 degrees. | 0:05:25 | 0:05:28 | |
-Winds rage at 400 miles per hour. | 0:05:29 | 0:05:31 | |
-Under an hour after -entering Jupiter's atmosphere... | 0:05:37 | 0:05:41 | |
-..the probe vaporizes. | 0:05:41 | 0:05:43 | |
-Jupiter's core remains a mystery. | 0:05:47 | 0:05:49 | |
-The journey to Jupiter's centre -remains impossible... | 0:05:53 | 0:05:57 | |
-..so scientists try to recreate it -in a lab. | 0:05:58 | 0:06:01 | |
-At the National Ignition Facility -near San Francisco... | 0:06:01 | 0:06:06 | |
-..they aim to achieve this -by using the world's largest laser. | 0:06:06 | 0:06:10 | |
-There are a lot of other facilities -where we can generate... | 0:06:12 | 0:06:15 | |
-..states that are found -at the centre of the earth... | 0:06:15 | 0:06:18 | |
-..or some of the other -terrestrial planets. | 0:06:19 | 0:06:21 | |
-This is the only place you can -recreate the interior of Jupiter. | 0:06:22 | 0:06:26 | |
-They take hydrogen, the most common -element in Jupiter, and freeze it. | 0:06:29 | 0:06:34 | |
-They then fire the laser -through a series of chambers... | 0:06:36 | 0:06:40 | |
-..a process which increases -the probe's size and power. | 0:06:40 | 0:06:44 | |
-Eventually, the beams converge. | 0:06:46 | 0:06:49 | |
-For a fraction of a second... | 0:06:55 | 0:06:57 | |
-..the laser bombards the hydrogen -with huge energy. | 0:06:57 | 0:07:01 | |
-At those very extreme pressures... | 0:07:04 | 0:07:07 | |
-..100 million atmospheres -of pressure... | 0:07:07 | 0:07:10 | |
-..chemistry is completely different. | 0:07:11 | 0:07:14 | |
-Instead of distorting -the chemical bond... | 0:07:17 | 0:07:20 | |
-..you're distorting -how the atom itself behaves. | 0:07:21 | 0:07:25 | |
-Matter behaves -in a fundamentally different way... | 0:07:25 | 0:07:29 | |
-..than we experience it -here, on earth. | 0:07:29 | 0:07:33 | |
-The atoms break down, transforming -the hydrogen gas into a liquid. | 0:07:35 | 0:07:39 | |
-A liquid metal. | 0:07:41 | 0:07:42 | |
-Essentially, you would have -this very dense structure... | 0:07:43 | 0:07:48 | |
-..and it would perhaps look like -this massive ball of mercury... | 0:07:48 | 0:07:52 | |
-..at the centre of Jupiter. | 0:07:53 | 0:07:55 | |
-At the centre of the planet... | 0:08:01 | 0:08:03 | |
-..it seems hydrogen creates -something similar to metal. | 0:08:03 | 0:08:08 | |
-The core rotates -at an immense speed... | 0:08:15 | 0:08:18 | |
-..generating a vast, highly -radioactive electromagnetic field. | 0:08:18 | 0:08:23 | |
-The magnetic field around Jupiter -is very strong. | 0:08:23 | 0:08:27 | |
-When you turn on a TV -and you pick some static... | 0:08:27 | 0:08:31 | |
-..some of it was caused -by Jupiter's magnetic field. | 0:08:32 | 0:08:36 | |
-Jupiter can interfere -with our television signals! | 0:08:36 | 0:08:40 | |
-Immense heat -is created inside Jupiter... | 0:08:40 | 0:08:44 | |
-..and we can see its effects -on the planet's surface. | 0:08:46 | 0:08:50 | |
-Heat comes from the core, -warming the atmosphere. | 0:08:56 | 0:09:00 | |
-We can see the clouds simmering... | 0:09:01 | 0:09:04 | |
-..as they carry chemicals -from the centre of the atmosphere. | 0:09:04 | 0:09:08 | |
-That's why we see these wonderful -colours in Jupiter's clouds. | 0:09:09 | 0:09:13 | |
-On earth, the sun's heat -drives our weather. | 0:09:16 | 0:09:21 | |
-But not on Jupiter. | 0:09:23 | 0:09:24 | |
-Heat rises -from the centre of the planet. | 0:09:32 | 0:09:35 | |
-A mixture of chemicals and gas -creates colourful clouds. | 0:09:37 | 0:09:41 | |
-Jupiter rotates faster than any -other planet in our solar system. | 0:09:46 | 0:09:51 | |
-It rotates once every ten hours, -which is much faster the earth. | 0:09:57 | 0:10:01 | |
-Like the sun, its equator -rotates quicker than its poles. | 0:10:04 | 0:10:08 | |
-Looking through a telescope... | 0:10:13 | 0:10:15 | |
-..we can see the planet is wider -at its equator than pole to pole. | 0:10:16 | 0:10:20 | |
-It rotates so quickly, -its centre bulges out. | 0:10:20 | 0:10:24 | |
-This marriage of heat and motion... | 0:10:25 | 0:10:28 | |
-..creates one of the largest storms -in the cosmos. | 0:10:28 | 0:10:32 | |
-As far as we know, Galileo was the -first person to see the red spot... | 0:10:33 | 0:10:38 | |
-..back in the 17th century... | 0:10:38 | 0:10:41 | |
-..so we know it's been there for -at least 400 years, if not longer. | 0:10:42 | 0:10:46 | |
-And it's a huge storm, -like a hurricane on earth. | 0:10:47 | 0:10:51 | |
-From space, you can see -these terrifying hurricanes... | 0:10:52 | 0:10:55 | |
-..as things spin around. | 0:10:57 | 0:10:59 | |
-These storms are created -by the planet's rotation. | 0:10:59 | 0:11:03 | |
-The Coriolis Force -causes these storms to form. | 0:11:03 | 0:11:06 | |
-On earth, cyclones weaken -when they hit land. | 0:11:08 | 0:11:11 | |
-But Jupiter has no land -to stop its storms. | 0:11:12 | 0:11:15 | |
-It's a storm -which has lasted at least 400 years. | 0:11:19 | 0:11:22 | |
-When we experience a storm -on earth... | 0:11:23 | 0:11:25 | |
-..we know it will only last -for a few days. | 0:11:25 | 0:11:28 | |
-Even the worst hurricanes -will last only a week or two. | 0:11:29 | 0:11:32 | |
-They eventually lose their energy. | 0:11:33 | 0:11:35 | |
-A 400-year storm -would be a huge problem. | 0:11:36 | 0:11:39 | |
-Galileo spotted it -and it's still there. | 0:11:40 | 0:11:43 | |
-I'm sure it will continue -for hundreds of years. | 0:11:43 | 0:11:47 | |
-Because of its size, Jupiter's -storms will last into the future. | 0:11:50 | 0:11:55 | |
-But how did Jupiter become so big? | 0:12:02 | 0:12:05 | |
-To answer this, we must go back -over four billion years. | 0:12:08 | 0:12:12 | |
-In the dust and gas left over -from the sun's formation... | 0:12:13 | 0:12:17 | |
-..the first planet forms - Jupiter. | 0:12:17 | 0:12:20 | |
-Jupiter is five times further -from the sun than the earth... | 0:12:22 | 0:12:27 | |
-..and probably formed -earlier than the others. | 0:12:27 | 0:12:30 | |
-It pulled in much more of the disc -around the sun before the others. | 0:12:31 | 0:12:36 | |
-The fact it's big -and started out so big... | 0:12:40 | 0:12:43 | |
-..means it mopped up matter -around the solar system... | 0:12:43 | 0:12:47 | |
-..including comets, dust and gases. | 0:12:47 | 0:12:49 | |
-Jupiter forms at the right time -and in the right place. | 0:12:52 | 0:12:56 | |
-Just at the point -where water vapour turns to ice. | 0:12:59 | 0:13:02 | |
-Jupiter is right at the point -where ice can form. | 0:13:06 | 0:13:09 | |
-At this point, -ice and water can exist. | 0:13:10 | 0:13:13 | |
-So when Jupiter was created... | 0:13:16 | 0:13:18 | |
-..one of the reasons it grew so much -was that ice could exist here. | 0:13:19 | 0:13:23 | |
-Planets like earth, Venus -and Mars are made of rock... | 0:13:23 | 0:13:27 | |
-..so they can't expand hugely. | 0:13:27 | 0:13:30 | |
-But in icy conditions, -mass can bind together. | 0:13:31 | 0:13:35 | |
-Once this had happened... | 0:13:35 | 0:13:37 | |
-..it was possible to pull in -all these gases around Jupiter. | 0:13:37 | 0:13:41 | |
-And as Jupiter grew bigger... | 0:13:42 | 0:13:44 | |
-..its ability to pull in more mass -also increased. | 0:13:45 | 0:13:48 | |
-That resulted in the huge planet -we see today. | 0:13:49 | 0:13:52 | |
-We're lucky to exist at all -because Jupiter is so big... | 0:13:53 | 0:13:56 | |
-..it could have mopped up everything -before the earth formed. | 0:13:57 | 0:14:00 | |
-The planet -eats everything in its reach... | 0:14:03 | 0:14:06 | |
-..to become the giant we see today. | 0:14:07 | 0:14:09 | |
-Had it continued to grow... | 0:14:12 | 0:14:14 | |
-..it's likely Jupiter -would have turned into a star. | 0:14:15 | 0:14:18 | |
-What turns into a star -depends on its mass. | 0:14:21 | 0:14:24 | |
-You reach a point -where something is big enough... | 0:14:25 | 0:14:29 | |
-..to start nuclear reactions, -which turns it into a star. | 0:14:30 | 0:14:34 | |
-Jupiter generates energy -from its core... | 0:14:35 | 0:14:38 | |
-..but it's not big enough -to start the nuclear reactions... | 0:14:39 | 0:14:43 | |
-..which would turn it into a star. | 0:14:44 | 0:14:46 | |
-So you could describe Jupiter -as a failed star. | 0:14:46 | 0:14:49 | |
-The night sky and the day sky -would look very different. | 0:14:50 | 0:14:54 | |
-We'd have two stars. | 0:14:54 | 0:14:57 | |
-And night might not be night, -it might be day. | 0:14:57 | 0:15:00 | |
-Four fifths of all the stars we see -in the night sky... | 0:15:01 | 0:15:05 | |
-..are two stars orbiting each other. | 0:15:06 | 0:15:08 | |
-So why didn't Jupiter become a star? | 0:15:13 | 0:15:16 | |
-Jupiter is immense. It's 1,000 times -the mass of the earth. | 0:15:18 | 0:15:22 | |
-But the sun is a million times -the mass of the earth. | 0:15:22 | 0:15:26 | |
-It's too small -for the processes at its centre... | 0:15:26 | 0:15:29 | |
-..to heat it to the level necessary -to fuse hydrogen into helium. | 0:15:30 | 0:15:35 | |
-After billions of years -gathering gases and dust... | 0:15:38 | 0:15:42 | |
-..Jupiter is finally created. | 0:15:42 | 0:15:44 | |
-But the planet is drifting, -and is moving towards the sun. | 0:15:47 | 0:15:51 | |
-In early days of the cosmos, -the sun pulls Jupiter closer. | 0:15:52 | 0:15:57 | |
-So what will save the planet -from a fiery death? | 0:15:59 | 0:16:03 | |
-. | 0:16:07 | 0:16:08 | |
-Subtitles | 0:16:18 | 0:16:18 | |
-Subtitles - -Subtitles | 0:16:18 | 0:16:20 | |
-Jupiter is the biggest planet -with the biggest influence. | 0:16:32 | 0:16:36 | |
-But beyond our solar system, -Jupiter is not unique. | 0:16:38 | 0:16:41 | |
-Scientists discovered the first -planet beyond our solar system... | 0:16:44 | 0:16:49 | |
-..some 20 years ago. | 0:16:49 | 0:16:51 | |
-51 Pegasi b -is a giant gas planet... | 0:16:51 | 0:16:54 | |
-..similar to Jupiter in every way, -except one thing. | 0:16:55 | 0:16:59 | |
-The planets we've discovered tend to -be far closer to their star... | 0:17:03 | 0:17:08 | |
-..than Jupiter is to our sun. | 0:17:08 | 0:17:11 | |
-Astronomers have since identified -over 1,000 similar planets. | 0:17:11 | 0:17:16 | |
-Many orbit -extremely close to their star. | 0:17:19 | 0:17:22 | |
-The planet WASP-33 b... | 0:17:24 | 0:17:26 | |
-..orbits so close to its star, -it's scorching. | 0:17:26 | 0:17:30 | |
-It's the hottest planet -ever observed in our galaxy. | 0:17:32 | 0:17:36 | |
-Some of the planets -are very close to their stars. | 0:17:38 | 0:17:43 | |
-But Jupiter -is relatively far from the sun. | 0:17:44 | 0:17:47 | |
-Some people suggest Jupiter formed -much further out... | 0:17:49 | 0:17:53 | |
-..and has moved closer to the sun. | 0:17:53 | 0:17:55 | |
-It currently sits five times further -away from the sun than earth. | 0:17:56 | 0:18:00 | |
-The theory is that other -Jupiter-like planets formed... | 0:18:01 | 0:18:05 | |
-..at similar distances -to where our Jupiter is. | 0:18:05 | 0:18:08 | |
-A reaction to the disc of dust -in the early system... | 0:18:09 | 0:18:13 | |
-..caused these planets -to move closer to their star. | 0:18:13 | 0:18:17 | |
-So the next question is, why didn't -this happen in our system? | 0:18:17 | 0:18:22 | |
-To answer this, scientists -created a computer model... | 0:18:25 | 0:18:29 | |
-..to examine how the planets -in our solar system were formed. | 0:18:29 | 0:18:34 | |
-We would build our models. | 0:18:38 | 0:18:40 | |
-We'd get a Venus right where Venus -is supposed to be. | 0:18:40 | 0:18:43 | |
-We'd get an earth right where -the earth is supposed to be. | 0:18:43 | 0:18:47 | |
-But where Mars is today... | 0:18:47 | 0:18:49 | |
-..we were usually getting a Venus -or earth-mass planet. | 0:18:49 | 0:18:52 | |
-No matter how we changed the model, -we always got a really big Mars. | 0:18:53 | 0:18:57 | |
-Our simulations show that Mars -where it is in the disc... | 0:18:57 | 0:19:00 | |
-..should be at least ten times -the mass it is. | 0:19:01 | 0:19:03 | |
-Something came in -and literally ate Mars as lunch. | 0:19:04 | 0:19:07 | |
-And that something was Jupiter. | 0:19:08 | 0:19:10 | |
-Jupiter was formed much closer -to the sun than it is today. | 0:19:12 | 0:19:16 | |
-In the beginning... | 0:19:19 | 0:19:21 | |
-..it collides with the debris -left over from the sun's formation. | 0:19:21 | 0:19:26 | |
-The sun's gravity -then pulls it closer. | 0:19:27 | 0:19:29 | |
-Jupiter spirals inwards... | 0:19:31 | 0:19:33 | |
-..hoovering up the raw materials -that should have made Mars. | 0:19:33 | 0:19:38 | |
-Seeing a great solution to the small -Mars problem was the Eureka moment. | 0:19:42 | 0:19:47 | |
-Maybe there's a mechanism out there. | 0:19:47 | 0:19:49 | |
-We know that planets migrate, -so let's put these things together. | 0:19:50 | 0:19:54 | |
-As Jupiter travels inwards... | 0:19:55 | 0:19:57 | |
-..it bulldozes the material -that lies in its path. | 0:19:57 | 0:20:01 | |
-On the inward migration -there's a lot of material there... | 0:20:01 | 0:20:05 | |
-..and it pushes -about 80% of it inward. | 0:20:05 | 0:20:08 | |
-When we make the movies in a certain -way it looks like a snowplough. | 0:20:08 | 0:20:12 | |
-It looks like Jupiter -will plummet into the sun. | 0:20:14 | 0:20:18 | |
-Then, unexpectedly, -it changes direction. | 0:20:23 | 0:20:26 | |
-A massive force is needed -to turn such a huge planet. | 0:20:28 | 0:20:32 | |
-It seems our second-biggest planet, -Saturn, has saved the day. | 0:20:32 | 0:20:37 | |
-It looks like Jupiter -starts moving closer to the sun... | 0:20:42 | 0:20:46 | |
-..but then Saturn's gravity -pulls Jupiter back out. | 0:20:46 | 0:20:50 | |
-Saturn is also a large planet. | 0:20:50 | 0:20:52 | |
-After a while, -the same process starts again. | 0:20:53 | 0:20:56 | |
-Jupiter moving closer to the sun -and Saturn pulling it back out. | 0:20:57 | 0:21:02 | |
-Over a long period of time... | 0:21:04 | 0:21:06 | |
-..it seems likely that Jupiter -will stay where it is today. | 0:21:06 | 0:21:10 | |
-Saturn helps Jupiter -move away from the sun. | 0:21:12 | 0:21:16 | |
-Both planets travel back -and reach their current position. | 0:21:20 | 0:21:25 | |
-Because Saturn was formed -at the same time... | 0:21:30 | 0:21:34 | |
-..that reaction -between Jupiter and Saturn... | 0:21:35 | 0:21:38 | |
-..helped to position both planets -in their current orbit. | 0:21:39 | 0:21:43 | |
-Saturn saves Jupiter. | 0:21:43 | 0:21:45 | |
-And all this allows another planet -to grow - the earth. | 0:21:48 | 0:21:52 | |
-Because when Jupiter moves out, -it leaves rocky debris behind. | 0:21:55 | 0:22:00 | |
-It's from this debris -that the earth forms. | 0:22:04 | 0:22:08 | |
-Our planet -and all the rocky planets exist... | 0:22:15 | 0:22:18 | |
-..because of Jupiter's epic journey. | 0:22:19 | 0:22:22 | |
-When the biggest thing in the solar -system moves this far this fast... | 0:22:27 | 0:22:30 | |
-..it changes everything around it. | 0:22:31 | 0:22:33 | |
-Five million years -after it first formed... | 0:22:35 | 0:22:39 | |
-..Jupiter reaches its present orbit. | 0:22:39 | 0:22:42 | |
-But this is still not -the solar system that we see today. | 0:22:43 | 0:22:47 | |
-By examining the solar system -in its early days... | 0:22:48 | 0:22:52 | |
-..it seems their distances -from the sun have changed. | 0:22:54 | 0:22:58 | |
-That's because Jupiter and its huge -gravity influences their orbit. | 0:22:59 | 0:23:04 | |
-Jupiter settles into its orbit... | 0:23:05 | 0:23:07 | |
-..but from its new position, -it can still wreak havoc. | 0:23:08 | 0:23:12 | |
-It even threatens to destroy -our earth. | 0:23:12 | 0:23:16 | |
-. | 0:23:19 | 0:23:19 | |
-Subtitles | 0:23:29 | 0:23:29 | |
-Subtitles - -Subtitles | 0:23:29 | 0:23:31 | |
-Over four billion years ago, -Jupiter forms... | 0:23:43 | 0:23:46 | |
-..and orbits -between the other planets. | 0:23:47 | 0:23:50 | |
-From this vantage point, it controls -the other planets and wreaks havoc. | 0:23:52 | 0:23:58 | |
-It's an incredibly violent time -in solar system history. | 0:24:04 | 0:24:08 | |
-We refer to that timescale... | 0:24:08 | 0:24:10 | |
-..several hundred million years -after the planets formed... | 0:24:11 | 0:24:15 | |
-..as the Late Heavy Bombardment. | 0:24:15 | 0:24:18 | |
-This was a horrific period. | 0:24:19 | 0:24:21 | |
-We're going back 4.2 billion years. | 0:24:25 | 0:24:27 | |
-The solar system -was a very busy place. | 0:24:30 | 0:24:32 | |
-All sorts of rocks and planets -were moving around. | 0:24:33 | 0:24:36 | |
-In a relatively short space of time, -they all collided... | 0:24:37 | 0:24:42 | |
-..and created the dance -we have at the moment. | 0:24:42 | 0:24:46 | |
-If you were on earth then... | 0:24:51 | 0:24:53 | |
-..rocks would constantly fall -from space, hitting the planet... | 0:24:53 | 0:24:58 | |
-..and throwing gases, rocks and dust -into the atmosphere. | 0:24:58 | 0:25:03 | |
-It would not have been -a very safe place to live. | 0:25:04 | 0:25:07 | |
-That period of chaos has ended. | 0:25:19 | 0:25:23 | |
-The earth is transformed -and the scars have disappeared. | 0:25:25 | 0:25:29 | |
-But the evidence is still there -if we look up to the moon. | 0:25:32 | 0:25:36 | |
-If you look up today at our moon, -we can see these ancient craters. | 0:25:38 | 0:25:44 | |
-They were created -4.6 billion years ago... | 0:25:44 | 0:25:48 | |
-..when Jupiter was throwing rocks -around our solar system... | 0:25:48 | 0:25:52 | |
-..hitting the earth and the moon. | 0:25:53 | 0:25:55 | |
-The moon doesn't have -an atmosphere... | 0:25:56 | 0:25:59 | |
-..so it has no weather. | 0:25:59 | 0:26:01 | |
-Without wind to blow the dust, -we can still see the craters. | 0:26:01 | 0:26:05 | |
-If you look at the moon, -you can see them today. | 0:26:06 | 0:26:08 | |
-Five years ago, the Spitzer Space -Telescope reveals a similar scene... | 0:26:11 | 0:26:16 | |
-..around a distant star. | 0:26:16 | 0:26:18 | |
-Astronomers see a vast disc -of gas and dust... | 0:26:20 | 0:26:23 | |
-..circling a young star -called Eta Corvi. | 0:26:23 | 0:26:26 | |
-Comets and asteroids swarming -into each other. | 0:26:28 | 0:26:32 | |
-Four billion years ago, the same -thing happened in our solar system. | 0:26:32 | 0:26:38 | |
-And in that early stage -of our history... | 0:26:40 | 0:26:43 | |
-..Jupiter started to -throw her weight around. | 0:26:43 | 0:26:47 | |
-Many comets and asteroids... | 0:26:50 | 0:26:52 | |
-..were travelling around the sun -between the planets. | 0:26:53 | 0:26:57 | |
-When approaching Jupiter, they were -thrown out or in, closer to the sun. | 0:26:57 | 0:27:02 | |
-With Saturn's help, Jupiter pushes -the other two planets further out. | 0:27:04 | 0:27:09 | |
-Uranus and Neptune swap places. | 0:27:10 | 0:27:12 | |
-Neptune slams into -frozen dust and gas... | 0:27:19 | 0:27:23 | |
-..in the solar system's -outer reaches. | 0:27:24 | 0:27:26 | |
-Debris is scattered far and wide. | 0:27:28 | 0:27:31 | |
-They collide -with the asteroid belt... | 0:27:36 | 0:27:39 | |
-..orbiting the planets -close to the sun. | 0:27:40 | 0:27:43 | |
-The asteroids are then thrown out, -hitting planets like earth. | 0:27:44 | 0:27:50 | |
-But this destruction -contains the seeds of creation... | 0:27:56 | 0:28:00 | |
-..because the icy comets -deliver a precious cargo - water. | 0:28:01 | 0:28:06 | |
-We're learning more and more -about the asteroids... | 0:28:08 | 0:28:12 | |
-..travelling -between Mars and Jupiter. | 0:28:13 | 0:28:16 | |
-On less than a dozen of those, -we've discovered ice... | 0:28:17 | 0:28:21 | |
-..which means there's water -close to the surface. | 0:28:21 | 0:28:25 | |
-They act as comets for part -of their journey around the sun. | 0:28:26 | 0:28:29 | |
-And if many of the asteroids which -hit earth during its formation... | 0:28:30 | 0:28:35 | |
-..carried ice like this... | 0:28:35 | 0:28:37 | |
-..it's likely that's where the water -in our lakes and seas came from. | 0:28:37 | 0:28:43 | |
-Every river, every raindrop -existing because of Jupiter. | 0:28:46 | 0:28:51 | |
-The giant planet -may even have started life itself... | 0:28:57 | 0:29:00 | |
-..as water reached earth -on board one of these comets. | 0:29:03 | 0:29:06 | |
-Jupiter helped create life -but it also protects life. | 0:29:11 | 0:29:17 | |
-NASA scans the skies every day... | 0:29:21 | 0:29:24 | |
-..for asteroids and comets -which could hit the earth. | 0:29:24 | 0:29:29 | |
-So far, they've spotted -over 10,000 of them. | 0:29:30 | 0:29:33 | |
-And it only takes one to hit -the earth to cause a catastrophe. | 0:29:36 | 0:29:40 | |
-Just three miles wide... | 0:29:42 | 0:29:44 | |
-..this small comet is big enough -to wipe out life on earth. | 0:29:45 | 0:29:49 | |
-Luckily, Jupiter is in the way. | 0:29:49 | 0:29:51 | |
-As Jupiter expanded... | 0:29:53 | 0:29:54 | |
-..it became the protector -of other planets. | 0:29:55 | 0:29:58 | |
-Its gravity pulled any stray rocks -and comets towards it. | 0:29:58 | 0:30:02 | |
-Some say Jupiter -allowed life to form on earth. | 0:30:05 | 0:30:08 | |
-It has protected us -from most cosmic collisions... | 0:30:09 | 0:30:12 | |
-..for billions of years. | 0:30:13 | 0:30:15 | |
-The way objects move in the solar -system is like a roller derby. | 0:30:17 | 0:30:22 | |
-All these objects moving around -the sun in the same direction... | 0:30:24 | 0:30:29 | |
-..but they have gravity and they -can interact with each other. | 0:30:29 | 0:30:34 | |
-The skater in white is an icy comet. | 0:30:34 | 0:30:37 | |
-The skaters in black -are gas planets, like Jupiter. | 0:30:39 | 0:30:44 | |
-The comet veers towards the planet. | 0:30:45 | 0:30:48 | |
-Until it encounters Jupiter. | 0:30:51 | 0:30:53 | |
-The comet is caught -by Jupiter's gravity. | 0:30:54 | 0:30:57 | |
-And it's catapulted -in another direction. | 0:30:58 | 0:31:02 | |
-It would be swung and escorted away. | 0:31:06 | 0:31:09 | |
-You could describe Jupiter as -the shepherd of our solar system. | 0:31:10 | 0:31:14 | |
-In the 1990s, astronomers -spotted a comet close to Jupiter. | 0:31:20 | 0:31:25 | |
-Too close to get flung out. | 0:31:25 | 0:31:27 | |
-Instead, Jupiter's gravity -rips the comet apart. | 0:31:29 | 0:31:34 | |
-These comets are fragile and -the effects of Jupiter's gravity... | 0:31:36 | 0:31:41 | |
-..is strong enough -to rip them apart. | 0:31:41 | 0:31:44 | |
-The original comet -was a few kilometres long. | 0:31:46 | 0:31:50 | |
-I watched it through -a very small telescope in Surrey... | 0:31:50 | 0:31:54 | |
-..along with 12 other people. | 0:31:55 | 0:31:58 | |
-As the comet hit -the dark side of Jupiter... | 0:31:59 | 0:32:02 | |
-..a few minutes later, -the planet turned... | 0:32:02 | 0:32:05 | |
-..and we could see black marks -in the planet's clouds. | 0:32:06 | 0:32:10 | |
-As the comet passed through -Jupiter's atmosphere... | 0:32:12 | 0:32:15 | |
-..it left black soot marks, and -these could be seen in the clouds. | 0:32:16 | 0:32:20 | |
-It was amazing to watch this unfold. | 0:32:21 | 0:32:23 | |
-Some 200 times more comets -and asteroids smash into Jupiter... | 0:32:25 | 0:32:29 | |
-..than smash into the earth. | 0:32:30 | 0:32:33 | |
-Jupiter is bigger -than the other planets... | 0:32:33 | 0:32:36 | |
-..so its gravity is stronger than -anything else in the solar system. | 0:32:37 | 0:32:41 | |
-That's why things are pulled -in Jupiter's direction. | 0:32:41 | 0:32:45 | |
-Our lives rely on Jupiter. | 0:32:51 | 0:32:53 | |
-As new planets are discovered -orbiting other stars... | 0:32:58 | 0:33:02 | |
-..without a partnership between -more than one large planet... | 0:33:02 | 0:33:07 | |
-..to keep the biggest one -in position... | 0:33:07 | 0:33:10 | |
-..it's difficult to find a system -similar to ours. | 0:33:11 | 0:33:15 | |
-Having a pair of big planets -like Saturn and Jupiter... | 0:33:15 | 0:33:19 | |
-..made it possible for small planets -like ours to exist. | 0:33:19 | 0:33:23 | |
-Jupiter makes life on earth possible -and helps protect that life. | 0:33:26 | 0:33:32 | |
-And it may even nurture alien life. | 0:33:37 | 0:33:40 | |
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-Subtitles | 0:33:54 | 0:33:54 | |
-Subtitles - -Subtitles | 0:33:54 | 0:33:56 | |
-Jupiter dominates -everything around it. | 0:34:06 | 0:34:09 | |
-The largest planet -in our solar system... | 0:34:13 | 0:34:16 | |
-..also has -the largest number of moons. | 0:34:16 | 0:34:19 | |
-There are dozens of moons orbiting -Jupiter - over sixty of them. | 0:34:20 | 0:34:26 | |
-Some of those are made of rock. | 0:34:28 | 0:34:31 | |
-Others are made of gases -and others a combination of both. | 0:34:31 | 0:34:35 | |
-Each one has different attributes. | 0:34:36 | 0:34:39 | |
-Jupiter has a huge influence -over all the moons. | 0:34:42 | 0:34:45 | |
-And perhaps making -one of them home to life. | 0:34:46 | 0:34:49 | |
-March 1st, 2007. | 0:34:52 | 0:34:54 | |
-The New Horizon space probe -flies past a moon called Io. | 0:34:55 | 0:34:59 | |
-As it passed Jupiter and the moon... | 0:35:00 | 0:35:03 | |
-..the probe turned around -and it saw something near Io. | 0:35:03 | 0:35:08 | |
-At first, scientists were confused. | 0:35:11 | 0:35:14 | |
-What could it be? | 0:35:15 | 0:35:17 | |
-They then realized -it was a huge volcanic eruption. | 0:35:18 | 0:35:22 | |
-This moon is the solar system's -most volcanic location. | 0:35:25 | 0:35:30 | |
-It's home to at least -400 active volcanoes. | 0:35:31 | 0:35:34 | |
-Io orbits Jupiter -in an elliptic orbit... | 0:35:36 | 0:35:40 | |
-..similar to the orbit -our moon takes around the earth. | 0:35:41 | 0:35:45 | |
-The moon's shape -changes all the time. | 0:35:46 | 0:35:49 | |
-Just like squeezing a tennis ball -in your hand over and over again... | 0:35:49 | 0:35:54 | |
-..and the ball tennis heats up... | 0:35:55 | 0:35:57 | |
-..the effect of Jupiter's gravity -heats up the Io moon. | 0:35:57 | 0:36:02 | |
-So much heat is released -by this process... | 0:36:06 | 0:36:10 | |
-..volcanoes appear -all over its surface. | 0:36:10 | 0:36:13 | |
-It's likely Io has been -twisted and turned many times. | 0:36:14 | 0:36:19 | |
-Sulphur dioxide -is emitted from the volcanoes... | 0:36:21 | 0:36:25 | |
-..and Jupiter's magnetic field -strips molecules of their electrons. | 0:36:25 | 0:36:31 | |
-They're carried along -the magnetic field around Jupiter... | 0:36:33 | 0:36:38 | |
-..creating auroras like the -Northern Lights we have on earth. | 0:36:40 | 0:36:45 | |
-Jupiter's magnetic field -transports chemicals... | 0:36:49 | 0:36:53 | |
-..from Io -to its neighbouring moon, Europa. | 0:36:53 | 0:36:57 | |
-That's why this place is our -best hope of finding alien life. | 0:37:00 | 0:37:04 | |
-When you look at pictures -of Europa's surface.... | 0:37:07 | 0:37:11 | |
-..you can see ice... | 0:37:11 | 0:37:13 | |
-..which contains huge fractures. | 0:37:15 | 0:37:18 | |
-It's similar to the landscape -of our North and South Poles. | 0:37:18 | 0:37:22 | |
-These cracks and ridges -on Europa's surface... | 0:37:25 | 0:37:28 | |
-..show that ice has moved here -at some point in the past. | 0:37:29 | 0:37:33 | |
-As there has been -so much movement... | 0:37:35 | 0:37:38 | |
-..it seems the layer of ice -on Europa's surface is quite thin. | 0:37:38 | 0:37:42 | |
-Jupiter's gravity -pushes and pulls Europa. | 0:37:49 | 0:37:52 | |
-It seems this sea is created... | 0:37:54 | 0:37:57 | |
-..because Jupiter's gravity, -along with the other moons... | 0:37:57 | 0:38:01 | |
-..warms Europa. | 0:38:02 | 0:38:03 | |
-It's warm enough for there to be -water as liquid under the surface... | 0:38:05 | 0:38:10 | |
-..but not hot enough to create -volcanoes like the ones on Io. | 0:38:10 | 0:38:14 | |
-We knew most of the moon -was covered in ice. | 0:38:17 | 0:38:20 | |
-But significant interest -has developed recently... | 0:38:22 | 0:38:26 | |
-..after geysers that push water out -from under this ice were found. | 0:38:26 | 0:38:31 | |
-November 2013. | 0:38:34 | 0:38:36 | |
-Analysing photographs -from the Hubble Space Telescope... | 0:38:36 | 0:38:41 | |
-..scientists spot -two giant geysers... | 0:38:41 | 0:38:44 | |
-..spewing water -above Europa's south pole. | 0:38:44 | 0:38:47 | |
-It's the best evidence yet of liquid -water beneath Europa's frozen crust. | 0:38:51 | 0:38:56 | |
-These geysers -are a significant discovery. | 0:38:59 | 0:39:02 | |
-It means there must be -liquid water underneath the ice. | 0:39:03 | 0:39:07 | |
-For life to evolve, -it needs water and other chemicals. | 0:39:12 | 0:39:16 | |
-And that's where Jupiter's -magnetosphere is important... | 0:39:17 | 0:39:22 | |
-..transporting chemicals from -the volcanic moon Io to Europa. | 0:39:22 | 0:39:27 | |
-Scientists think this delivers -sulphur, carbon and other minerals. | 0:39:28 | 0:39:33 | |
-Finding water elsewhere in -the solar system is very exciting. | 0:39:38 | 0:39:43 | |
-If we named one place where life -could exist in our solar system... | 0:39:44 | 0:39:49 | |
-..Europa would be -at the top of the list. | 0:39:49 | 0:39:52 | |
-So Europa's geysers -are a major discovery. | 0:39:53 | 0:39:56 | |
-One of the exciting aspects -of seeing this geyser on Europa... | 0:39:56 | 0:40:00 | |
-..is it means the liquid ocean under -the surface has a way to get out. | 0:40:00 | 0:40:05 | |
-Maybe there's a way for stuff from -the surface to get into the ocean. | 0:40:05 | 0:40:09 | |
-It could be that in this ocean... | 0:40:10 | 0:40:12 | |
-..there's a nutrient-rich -supply of food. | 0:40:13 | 0:40:16 | |
-Life needs water and food. -And something else. | 0:40:20 | 0:40:23 | |
-You also need an energy source. | 0:40:24 | 0:40:26 | |
-On the earth, that's the sun. -Its light warms the surface. | 0:40:27 | 0:40:30 | |
-On Europa, if you're in that ocean -it's probably pitch black. | 0:40:31 | 0:40:35 | |
-But here on earth, -life can exist without the sun. | 0:40:37 | 0:40:42 | |
-Around 11% of our planet's surface -is covered by glaciers. | 0:40:45 | 0:40:50 | |
-Underneath these glaciers, -there is life. | 0:40:50 | 0:40:54 | |
-They're extreme conditions - -zero degrees Celsius all year round. | 0:40:58 | 0:41:03 | |
-No energy from the sun reaches it... | 0:41:03 | 0:41:06 | |
-..and there is very little organic -matter or food for life to exist. | 0:41:06 | 0:41:11 | |
-So we have water and we have heat -coming from inside the moon. | 0:41:11 | 0:41:15 | |
-The seas under the layer of ice -on Europa's surface... | 0:41:18 | 0:41:22 | |
-..is one of a few places -in the solar system... | 0:41:22 | 0:41:25 | |
-..where we know the conditions -could sustain life. | 0:41:26 | 0:41:29 | |
-If there is life beneath Europa's -surface, it may outlive us all. | 0:41:40 | 0:41:46 | |
-Because, five billion years -from now, the sun is going to die. | 0:41:48 | 0:41:53 | |
-We know for certain -that the sun will die. | 0:41:59 | 0:42:02 | |
-In five billion years, that will be -the beginning of the end. | 0:42:03 | 0:42:08 | |
-When the sun reaches the end -of its life, it will expand... | 0:42:12 | 0:42:16 | |
-..and swallow -some of the planets closest to it. | 0:42:17 | 0:42:20 | |
-Mercury, Venus and the earth... | 0:42:20 | 0:42:23 | |
-..will probably be swallowed -by the sun as it expands. | 0:42:23 | 0:42:27 | |
-The inner planets burn up. | 0:42:29 | 0:42:32 | |
-Will Jupiter be next? | 0:42:33 | 0:42:35 | |
-It's likely the sun will expand -very close to the earth's orbit. | 0:42:40 | 0:42:44 | |
-There's a degree of uncertainty -about this. | 0:42:45 | 0:42:48 | |
-But the planets further away -from the sun will not be engulfed. | 0:42:49 | 0:42:55 | |
-It's likely that, -as the sun expands... | 0:42:59 | 0:43:02 | |
-..the larger planets further away -will get more light and heat. | 0:43:03 | 0:43:08 | |
-There is water present on moons -around Jupiter and Saturn. | 0:43:10 | 0:43:15 | |
-We could see life flourish -on those moons. | 0:43:16 | 0:43:19 | |
-Moons like Europa will be far more -habitable than they are today. | 0:43:23 | 0:43:28 | |
-We could see the ice on Europa melt. | 0:43:30 | 0:43:34 | |
-Perhaps Europa will be -life's last refuge as the sun dies. | 0:43:41 | 0:43:45 | |
-In the distant future... | 0:43:47 | 0:43:49 | |
-..Jupiter could enjoy temperatures -which are similar to earth's today. | 0:43:49 | 0:43:55 | |
-So in billions of years, -maybe the moons orbiting Jupiter... | 0:43:56 | 0:44:01 | |
-..will be a place -where people could live. | 0:44:02 | 0:44:05 | |
-In our dying solar system... | 0:44:08 | 0:44:10 | |
-..Jupiter's moons -may offer a safe haven. | 0:44:10 | 0:44:13 | |
-But for how long? | 0:44:14 | 0:44:15 | |
-The sun's outer layers -will gradually disappear... | 0:44:17 | 0:44:21 | |
-..but the core, -the white dwarf, will remain. | 0:44:22 | 0:44:25 | |
-Over time, it will gradually -get darker and darker. | 0:44:26 | 0:44:29 | |
-You wouldn't see the sun -from the surface of Jupiter... | 0:44:30 | 0:44:34 | |
-..when the sun -undergoes its final stage... | 0:44:34 | 0:44:37 | |
-..to become a piece of nuclear waste -drifting in outer space. | 0:44:37 | 0:44:41 | |
-Jupiter and its moons -will become dark once more. | 0:44:47 | 0:44:51 | |
-The white dwarf will lose its energy -and get darker and darker. | 0:44:52 | 0:44:58 | |
-The gases and dust left over -from the sun will still be there... | 0:45:00 | 0:45:05 | |
-..but it will be a dark and cold -area of the universe. | 0:45:08 | 0:45:12 | |
-Jupiter, because of its size, -will still be there... | 0:45:13 | 0:45:16 | |
-..orbiting what is left -of the sun forever. | 0:45:18 | 0:45:21 | |
-Jupiter will live on. | 0:45:29 | 0:45:30 | |
-And with it lives the hope of life. | 0:45:32 | 0:45:35 | |
-Any remaining water in places -like Europa will turn back to ice. | 0:45:36 | 0:45:41 | |
-It will be extremely cold. | 0:45:45 | 0:45:47 | |
-People couldn't live there -but bacteria could survive. | 0:45:47 | 0:45:51 | |
-Five billion years from now, -Jupiter will take centre stage. | 0:45:54 | 0:45:58 | |
-Before long, we can reveal -more of Jupiter's secrets. | 0:46:04 | 0:46:08 | |
-In August 2016, the Juno spacecraft -will go there... | 0:46:11 | 0:46:16 | |
-..opening a new chapter in the -big story of this huge planet. | 0:46:16 | 0:46:20 | |
-Jupiter has had a huge influence -on our solar system. | 0:46:27 | 0:46:32 | |
-That's evident. | 0:46:33 | 0:46:34 | |
-Jupiter has been here -since the beginning... | 0:46:37 | 0:46:41 | |
-..and it will be here until the end. | 0:46:41 | 0:46:43 | |
-Creator, protector, -nurturer and survivor. | 0:46:46 | 0:46:49 | |
-Jupiter shaped the solar system -that we see today... | 0:46:51 | 0:46:54 | |
-..making life possible on earth, -and perhaps beyond. | 0:46:55 | 0:46:59 | |
-We certainly owe Jupiter -a huge debt of gratitude. | 0:47:00 | 0:47:04 | |
-S4C subtitles by Eirlys A Jones | 0:47:34 | 0:47:36 | |
-. | 0:47:36 | 0:47:37 |