- 4 days ago
The worlds that surround our planet are all made of rock, but there the similarity ends. Some have a beating geological heart, others are frozen in time.....
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00:07We live on a world of wonders, a place of astonishing beauty and complexity.
00:17We have vast oceans, incredible weather, giant mountains, and spectacular landscapes.
00:27If you think that this is all there is, that our planet exists in magnificent isolation,
00:34then you're wrong.
00:36We're part of a much wider ecosystem that extends way beyond the top of our atmosphere.
00:48I think we're living through the greatest age of discovery our civilization has known.
00:53We voyage to the farthest reaches of the solar system.
00:58We photograph strange new worlds, stood in unfamiliar landscapes, tasted alien air.
01:09Now the laws of physics are simple and they're universal.
01:13What applies here applies everywhere else up there.
01:18But it's fascinating that they can manifest themselves in so many different ways across the solar system.
01:29In this program, I'm going to look at how the universal forces of nature that created all this can also
01:37wreak devastation across the solar system.
01:42How they can be the death of a planet.
01:48And how they can keep other worlds alive.
01:57I can just see pieces of molten rock rising up just below my chin.
02:04These forces are so far reaching, they bridge the depths of space and transform a world long thought dead into
02:13a world of perpetual change and everlasting youth.
02:19The intense source of heat that powers that eternal change also drives one of the most spectacular sights in the
02:28solar system.
02:49Very lovely.
02:49These forces look like the earth.
02:49Now the moon sets us closed and tangible and brief.
02:49And start by relying on the-the activity of the earth.
02:49Moving by four variables that today i've done a sketches for gluten- manga.
02:50How does this mean?
02:53The Venus Orenians support the queenmayıicle 실패acă.
02:53As the healing of the earth under the local Eight of districts have done a show that sigui fine.
02:54The re vitals the size by
02:55emis and has the countryside being the nine cells have done to share economic passiert
03:18I've come to one of Earth's natural wonders.
03:23The Grand Canyon in Arizona.
03:29It's a place to be humbled by nature.
03:34Well, this is undoubtedly one of the most beautiful places I've seen on Earth.
03:42From sunrise to sunset, the changing light brings this immense landscape to life.
03:50You hear stories of people coming here at sunrise with tears in their eyes at the majesty
03:55of the view and I can see why.
04:00It's incredible to think that this enormous valley was etched and carved by the action of
04:07running water over just a few million years.
04:14Our knowledge of natural wonders like the Grand Canyon was once limited to our own planet.
04:23But the space age has brought new worlds into view.
04:34This is Mars, the red planet.
04:37Fourth rock out from the sun, it has a canyon so vast you could fit our own Grand Canyon into
04:43one of its side channels.
04:51Named after the space probe that first saw it, this is the Valles Marineris.
05:01Eight kilometres deep and over 3,000 kilometres long, on Earth, it would run all the way from
05:09Los Angeles to New York.
05:18We're beginning to get a deep and quite profound understanding of the way that Mars has evolved
05:25geologically because we are now there, because we now have eyes and ears on the surface.
05:31And there really is no substitute for actual exploration, for actually going somewhere, touching
05:38it and taking pictures of it.
05:43Look at this picture.
05:46This is a picture of a sunset.
05:50These are pictures of clouds.
05:54It's amazing to think these incredibly familiar-looking photographs were taken on the surface of Mars.
06:03This picture, or this amazing colour picture, I could have got a camera here and just snapped
06:09any picture and it would have looked exactly like this one.
06:13In the Grand Canyon, you can see the Colorado River running in the bottom of the valley so
06:18you can understand how this landscape was made, whereas here on Mars, there's no sign of any water.
06:25So Mars is a puzzle in place.
06:32Despite all the similarities between Mars and Earth, it's the differences between these two
06:38planets that are most telling.
06:40Mars is now a desolate, dead wasteland, a world where the processes that sculpted its familiar
06:47landscapes seized up long ago.
06:54It's fascinating for me as a physicist to see how the same basic simple laws of nature can
07:02play out in such radically different ways and produce such astonishingly varied, beautiful,
07:11and violent, and dead worlds out there across the solar system.
07:37The big island of Hawaii, in the middle of the Pacific Ocean, holds the key to what happened to Mars.
07:44This is the perfect place to witness how a planet can be kept alive by nothing more than the simple
07:52flow of heat.
07:55You can smell the volcanic ash coming into the helicopter and everywhere you look, it looks like a...
08:04It's almost like an apocalyptic scene.
08:09This volcano is Kilauea, which means spewing heat.
08:14It's been erupting almost continuously since 1983.
08:19There, you can see bolts and rocks flowing down the side of the mountain, just cutting a swathe through the
08:26trees.
08:27This might look like widespread destruction, but volcanic eruptions are Earth's geological heartbeat.
08:36Active volcanoes make our planet a vibrant living world.
08:40That is the most spectacular demonstration of the planet being geologically alive that I've ever seen.
08:56A few kilometres north of Kilauea, you can see just what volcanic action can produce given enough time.
09:07The islands of Hawaii were built entirely by volcanoes.
09:13Today, these mountains are the largest volcanoes on our planet.
09:19And we've seen landscapes just like this on Mars.
09:27It's quite an experience, being four kilometres high.
09:30It makes you out of breath, you sniff a lot, because your nose becomes a...
09:34..and makes you feel like you've had a few drinks.
09:39Well, this is Mauna Kea, one of the five volcanoes that make up the big island of Hawaii.
09:44I've known about it since I was very little, because it's one of the most famous observatories on the planet.
09:50Everywhere you look, surrounded by our eyes to the cosmos.
09:56Now, although this mountain is four kilometres above the surface of the Pacific,
10:00it's actually ten kilometres above the surface of the Pacific floor.
10:05That makes it the highest mountain on Earth, over a kilometre higher than Mount Everest.
10:10But it is a tiny volcano compared to the biggest volcano on the surface of Mars.
10:29This is Olympus Mons, named after Mount Olympus, the mythical home of the Greek gods.
10:35This vast outpouring of lava stretches over 550 kilometres across.
10:43But it's the height of this volcano that is breathtaking.
10:49It soars 25 kilometres into the Martian sky, nearly three times the full height of Mauna Kea.
10:58But Olympus Mons isn't just the tallest volcano in the solar system.
11:03It's the highest mountain we know.
11:07There are striking similarities between the volcanic landscapes here on Hawaii,
11:13and the giant volcanoes found on Mars.
11:15These similarities can be traced back billions of years to the fiery birth of the solar system.
11:25All this heat you can see driving this spectacular volcanic activity is a relic, a hangover of the Earth's formation.
11:34Now, all the rocky planets, Earth, Mars, Venus, Mercury, were formed in the same way.
11:41They came from a collapsing dust cloud over four and a half billion years ago.
11:54With the ignition of the sun, our solar system was born.
11:59Little by little, the rocky bodies grew, falling together under their own gravity.
12:06This process not only generated immense amounts of heat, it also delivered radioactive material to the cause.
12:18These two ancient sources of heat power Earth's volcanoes to this day.
12:24But the volcanoes on Mars are little more than a petrified memory of a distant past.
12:31When we look down on the surface of Mars, we see no evidence of this kind of volcanic activity.
12:38As far as we can tell, Mars is a dead world.
12:44Mars must have had similar inner heat to Earth to build its volcanoes.
12:49Yet something obviously happened to stop the red planet's geological heartbeat.
12:57Now, as everyone who's left a hot cup of tea sat on the kitchen table knows, hot things lose heat
13:03to their cooler surroundings.
13:05And what's true for cups of tea in physics is also true for planets.
13:10This is hot, and that up there, space, is cold.
13:15And so planets lose heat to space.
13:21Now, Mars is a much smaller planet than the Earth.
13:24It's about half the diameter.
13:28It's an eighth of the volume.
13:29So there is much less heat trapped in there to begin with.
13:34Now, planets lose heat to space through their surfaces.
13:38And smaller things have a larger surface area in relation to their volume than big things.
13:45So that means that Mars will lose its heat to space much quicker than the Earth does.
13:55When the interior of Mars grew cold, the mighty volcanoes lost their lifeblood.
14:02The red planet's geological heart died.
14:06And millions of years ago, the surface of Mars ground to a halt.
14:12The fate of a whole planet was destined by the simplest of laws of physics.
14:33Since the dawn of human history, we've been able to gaze up into the night sky.
14:37But we're lucky because we're the first generation that's been able to build machines to actually go to those planets
14:43and moons.
14:45And we found that they're more beautiful, more violent, more magnificent and fascinating than we could have possibly imagined.
14:57The more worlds we study, the more we realize that our solar system is a cosmic laboratory.
15:04Even the slightest differences in size or position can create a world radically different from its neighbors.
15:15So here on Earth, we have one beautiful manifestation of how those simple laws of nature can play out, how
15:24they can build a planet.
15:26In Mars, we have another example. What happens when you take a planet that's smaller than Earth and move it
15:32further away from the Sun?
15:34Well, it loses its heat more quickly and it becomes geologically inactive.
15:38But what would happen if you took a planet just like the Earth and moved it a little closer to
15:44the Sun?
15:46Well, we know of such a planet. It's the brightest point of light in our night sky.
15:57So similar in size to our own world, this planet has been called Earth's twin.
16:05This is Venus. Orbiting closer to the Sun, Venus was named for its shining beauty.
16:17But our planetary twin hides its true identity beneath a thick blanket of cloud.
16:34Over the last four and a half billion years, Venus has turned into an unimaginably oppressive world.
16:42The atmosphere is so dense that the pressure is crushing.
16:46It's 90 times atmospheric pressure here on Earth.
16:51Venus takes 243 days to rotate once on its axis.
16:56That means its day is longer than its year.
17:02Venus has the hottest average surface temperature, other than the Sun's, anywhere in the solar system.
17:08470 Celsius.
17:17I've come to India to a place called the Deccan Traps.
17:24Hidden in this lush green landscape are tantalising clues to understanding how immense heat caused Venus to choke to death.
17:35You know, when you look at this landscape today, it's incredibly peaceful and beautiful rolling green hills.
17:42But I think it's astonishing to think that everything you see down there is lava.
17:49This whole landscape, half a million square kilometres of it, was created in an ongoing volcanic eruption that lasted for
17:58a million years.
18:02If you take away the green foliage, the underlying landscape of lava is actually very similar to what we see
18:10on Venus.
18:14Using radar to peer down through the clouds, the surface of Venus was finally revealed.
18:20It's covered with floods of solid lava, just like we see in India, but on a scale many thousands of
18:29times larger.
18:30We've also counted over 50,000 volcanoes, the most on any planet in the solar system.
18:39Venus is a similar size to Earth, so it may still have a hot geological heart powering its volcanoes.
18:47But as yet, we haven't witnessed any eruptions.
18:54The ancient floods of lava we see on Venus, and here in India, were created in much the same way.
19:02For both planets, this was volcanic activity in overdrive.
19:06The eruptions here in India, 65 million years ago, affected the Earth's climate so much
19:12that they thought to have played a major role in their mass extinction event at the end of the Cretaceous
19:17period,
19:18which wiped out over two-thirds of the species on Earth.
19:22Now, life on Earth recovered, but Venus wasn't so lucky.
19:30The intense volcanic activity on both planets didn't just blast out molten rock.
19:36It also released copious amounts of gases, like carbon dioxide.
19:45But slight differences in the way the laws of physics played out on Venus
19:50helped push our cosmic twin down a path of no return.
19:57Venus and Earth reacted very differently to the same kind of volcanic cataclysm.
20:02And the reason for that is something that happens so often on Earth
20:05that we take it for granted and just moan about it.
20:17The rain plays a significant role in keeping our planet a pleasant place to live.
20:25Acting as part of a global recycling system, rain keeps our atmosphere in balance,
20:32.
20:42But on Venus, the laws of physics have made
20:46it impossible for rainfall to cleanse its atmosphere in fact there's no liquid water at all
20:55venus lost its water essentially because it's hotter than the earth see temperature is just a
21:01measure of how fast things are moving around so on venus the oceans would have evaporated
21:07into the atmosphere and that water in the atmosphere would be moving around extremely
21:12quickly simply because it's hot venus is so close to the sun and so hot those water molecules are
21:18moving so fast that the gravity of the planet can't continue to hold them in the atmosphere
21:24so they simply escape up into space
21:31with no water there is no rain on venus for billions of years there has been nothing to temper the
21:39build
21:40up of volcanic gases in its atmosphere venus ended up cocooned in a thick high pressure dense blanket
21:51of carbon dioxide and that made the temperature rise and rise and rise
21:58turning venus into the hell-like world we see today
22:15compared to scorched venus and frozen mars our home is a very special ball of rock
22:36earth has been called the goldilocks planet because everything is just right
22:46our world is unique but it doesn't exist in splendid isolation it is intimately connected with its cosmic
22:55neighbors earth is not the master of its own destiny and it never has been
23:02the life and death of our planet is influenced by forces emanating from the very depths of space
23:15as we better understand our place in space we've come to realize that our sharing of the same
23:22physical laws with the other worlds in the solar system isn't the only connection we have with them
23:29because those same laws lead to a direct physical connection between the earth and the
23:37other worlds out there that is subtle is complicated but can sometimes be extremely powerful
23:53out in the farthest reaches of the solar system a vast world that have a direct impact on our very
24:00existence
24:05this is our sun from 10 billion kilometers away just another star in a sea of stars but as you
24:14head
24:14towards the light you enter a realm of giants
24:21the furthest planet from the sun is icy neptune with its thick blue methane atmosphere
24:33uranus uranus uranus comes next the only planet that lies on its back
24:41further in towards the sun and the planets get even bigger saturn with its beautiful rings of ice
24:50the moon finally we reach the king of the giants jupiter jupiter jupiter is the largest planet in the solar
25:04system so big you could fit earth inside it over one thousand times it's made up of the same stuff
25:13as
25:13as our sun hydrogen and helium the most common elements in the universe in its thick churning
25:20atmosphere gigantic storms have raged for centuries
25:28now astrologers have said for years that jupiter influences our lives but we now have scientific
25:35evidence that this mighty planet does have a significant connection with our own small world
25:44jupiter is so different to our planet you know a big ball of gas half a billion kilometers away
25:51it's difficult to see how it could have anything to do with us at all
25:55but despite the fact that astrology is a load of rubbish jupiter can in fact have a profound influence on
26:03our
26:03planet and it's through a force that well surrounds us and penetrates us and binds the galaxy together gravity
26:19gravity is one of the fundamental forces of nature it exists between all objects and the effects of the
26:28gravitational field extend way beyond the planet that creates it
26:37gravity is by far the weakest force of nature i mean i can pick this rock up off the ground
26:43and there's
26:44the entire planet planet earth trying to pull it down but it's the only force that has an influence
26:50across the entire solar system and that's because although it's weak it has a an infinite range it never
26:56quite goes away so no matter how far you go you feel the force of gravity as a planet although
27:03it
27:03drops and drops and drops and drops away jupiter has the most powerful gravitational field of all the
27:12planets and it's the gas giant's gravity that can directly influence the orbits of asteroids and other
27:20wandering space debris jupiter is so massive by far the most massive planet in the solar system that
27:29its gravitational field can have a profound influence on passing into planetary stuff it can do three
27:35things firstly it can capture the stuff literally hoover it up secondly it can deflect the stuff such that it
27:43throws it out of the solar system but thirdly and most importantly for us it can deflect stuff
27:49onto a direct collision course with our planet
28:00influenced by jupiter's gravity today right now we are highly vulnerable from asteroid impacts
28:09but we do have sentinels standing guard
28:16on top of the mountain of heliakala on the hawaiian honeymoon island of maui i've come to see professor
28:23nick kaiser who's searching our solar system for potentially hostile space debris
28:31the prime task is to try and find killer asteroids things that are out there in the solar system
28:36that might hit the earth there's an air of hollywood about it isn't there in in some sense well well
28:43that's right i would say a lot more resources have been spent on making movies about killer asteroids
28:48than actually finding them anything that's a kilometer in size if it hit the earth it would be
28:54devastating right it would probably kill nearly everyone on the planet
29:02each night using a revolutionary billion pixel digital sensor the team scans a vast swathe of the
29:11sky they're looking for any unidentified objects that might be heading our way so any one of these points
29:19of light could in fact be an asteroid that that's right and it's very likely in fact it's almost
29:26certain that there are asteroids in that image right the problem is how do you figure out which ones
29:31they are yeah the camera captures several images of the same patch of sky taken minutes apart the team
29:42can then see if anything has moved relative to the background of stars what we've done here is
29:48taken two images and subtracted them and you see the stars have nearly all gone away right but there's
29:54a couple of interesting things left if you look over here you see a dark thing and a white thing
30:00so
30:00that's something which was there in the first image and there in the second image and there's another one
30:07here so even on this tiny patch of sky we've already detected two objects what that means is when we
30:13do that kind of analysis on a whole field of view we'll detect hundreds of objects
30:23the beauty of our nice sky belies the potential danger it holds in store
30:30over 2 000 objects have been identified that pass close to the earth with something like 400
30:37that could be on a future collision course
30:42and all of these menacing lumps of rock at some point come under jupiter's gravitational influence
30:51now if you ever needed a demonstration of how congested the space is near the earth
30:57just look at this movie of the near-earth objects so here's mercury venus the earth mars
31:06and out here's jupiter here's the asteroid belt but look at the congestion in there every one of
31:12those points of light is an asteroid that we know of just look at the earth swimming through them
31:19so when you look up into the nice clear night sky and you want to be reassured that we're all
31:24nice
31:24and safe just remember this movie
31:31our planet is on a deadly journey earth is trapped in a cosmic game of dodgeballs it orbits the sun
31:41a game where the gravitational stranglehold of jupiter regularly throws asteroids our way
32:00jupiter's gravitational influence on passing space debris has made our planet a world under constant
32:07bombardment one of the most famous meteorite impact sites is the baringer crater in arizona
32:18in arizona
32:1950 000 years ago uh 300 000 ton 50 meter in diameter lump of iron and nickel entered the earth's
32:27atmosphere
32:28and made this crater and it should remind us that our environment doesn't just stop at the top of our
32:35atmosphere our environment stretches out into the solar system to the very edges of the solar system to
32:42wherever this rock came from
32:47in the grand scheme of things the asteroid that struck here was relatively small and innocuous
33:06but there are much larger impact craters hidden in earth's landscapes that have far more
33:13devastating tales to tell
33:19200 years ago white settlers crossed the ancient appalachian mountains here in america
33:25to seek new land out west
33:29little did they know what they were walking into
33:35well this place for me feels like the very definition of small town america it's on the border
33:41between virginia kentucky and tennessee and it's the kind of town where you feel that nothing much has
33:47changed for the last 100 years but this place was the site way back in history of a violent cosmic
33:58intervention
34:02this is middlesbrough kentucky it's a town built inside a meteorite impact crater
34:15the asteroid that struck here would have been huge around half a kilometer across hitting the earth well over 200
34:23million years ago
34:28you know i find it fascinating that when you look out of this view you
34:31don't really see a an obvious crater and indeed it wasn't until the 1960s that anybody had any idea
34:37that there was a colossal impact from space just over there centered right on the 18th hole of the golf
34:47course
34:52we now know where the giant asteroid that struck here could have come from
35:04located between jupiter and mars is a vast reservoir of rocky debris that forms the asteroid belt
35:12and it's this ancient rubble that jupiter our neighborhood giant can nudge towards the earth
35:27well here's my model of the solar system there's the sun in the middle and then the earth mars
35:37jupiter and then the asteroids sort of scattered in between a big region actually between mars and
35:44jupiter in fact they extend over 150 million miles which is further than the distance from the earth to
35:52the sun now this is my coffee by the way which doesn't represent anything i'll put it over there but
36:01now and
36:01again because of collisions in the asteroid belt a stray asteroid will get thrown into the position
36:07where they keep rhythmically meeting jupiter over and over again because jupiter is such a massive planet
36:13that means that it gets a kick it gets a gravitational kick and that changes the orbit of these asteroids
36:19and over time their orbit can become well elongated or elliptical rather than circular that means that
36:28they can get thrown in to the inner solar system and cross the orbits of the inner planets including
36:34the orbit of the earth and you get a potentially catastrophic collision
36:47jupiter was once thought to be our protector its enormous gravity swallowing up dangerous asteroids
36:54yet we now realize its gravitational influence can propel some of those asteroids in our direction
37:03but surprisingly catastrophic impacts with space debris might not be a bad thing at least in earth's past
37:16impacts from space shaped our planet they made our world what it is today
37:21take life on earth for example now it's possible probable even that impacts on a colossal scale change the
37:30climate so much that huge swathes of life on earth were wiped out creating ecological niches into which
37:39other species could evolve us for example
37:45it's incredible to think that a planet half a billion kilometers away could dictate the fate of our
37:52world jupiter's immense gravity bridges the depths of space and even though its power could one day
38:02devastate earth that same gravitational field breathes life into other corners of the solar system
38:10for better or worse jupiter's powerful gravitational field has had a direct influence on our planet
38:18you know we're part of a much wider ecosystem that extends to the very edges of the solar system
38:24and that ecosystem is bound together by the force of gravity and it's gravity that has power to bring worlds
38:32to
38:40our life
38:43our understanding of the solar system began much closer to home
38:50gazing down at us it was our moon with its regularly changing face
38:55that first fired our interest in worlds beyond our own
39:03when we could look further out we discovered the solar system was full of moons each invisibly
39:10connected to their parent planet by gravity
39:18our moon is a cold geologically dead world but the powerful gravitational bond that exists between
39:25another moon and its parent planet has done something astonishing
39:32it has brought this moon to life making it the most violent place in the solar system
39:40400 years ago it was galileo who first looked up at the night sky through a telescope
39:48turning his attention to jupiter he noticed that this giant planet was not alone
39:57oh yeah that's absolutely magnificent you see a disc surrounded by well i can see three points of
40:07light galileo over several nights saw four points of light and he correctly surmised that those are
40:13actually moons other worlds in orbit around jupiter
40:22jupiter's four largest moons are named after the four lovers of the greek god zeus
40:31furthest out is callisto then there's huge ganymede the largest moon in the solar system
40:40next is icy europa and finally the small yellow-tinged moon nearest jupiter io
40:51so the legend goes zeus tried to protect his lover io by turning her into a cow to hide her
40:58from the
40:58gaze of the jealous gaze of his wife hira but it didn't work and hira sent a gadfly to torment
41:06io and it was prescient in a way to name that satellite io the the tormented moon because we've
41:15since learned that it is indeed an incredibly tormented world
41:23for 400 years we expected io to be as dead as our own moon
41:29but in the late 1970s when the first spacecraft passed by jupiter
41:33we finally saw io up close
41:41but it didn't make any sense as here was a moon with no meteorite impact craters
41:51now it's impossible to believe that io could have escaped the bombardment that we see on our moon and
41:58practically every other body in the solar system so the only explanation is that that surface is young
42:04it must have been recently produced and that in turn means that io that tiny moon of jupiter out there
42:14must
42:15be a geologically active world the truth about io would blow us away
42:32we may not have stood on io but there are places we can go here on earth to help unlock
42:38its secrets
42:41this is ethiopia in east africa
42:45we're being flown out by military helicopter to the very hot very inhospitable afar region in the northeast of the
42:54country
43:00and this is what i've come to see
43:11it's one of the rarest geological phenomena on our planet a volcano with a lake of molten lava
43:23as the sun goes down the lava lake comes to life
43:34this volcano is called erta ale by the local afar people it means smoking mountain
43:45for many this place is a vision of hell
43:55yet it holds the key to understanding io a world over half a billion kilometers away
44:04this hot tortured landscape of lava will be our home for the next three days temperatures here reach 50
44:13celsius in the shade and we're camping right on top of the volcano
44:21but we're in good hands as io specialist dr ashley davis is part of the team
44:31it is absolutely spectacular it's extraordinarily beautiful you feel like you're looking into the
44:38core of the planet it's a window into the interior of the earth so magma's rising up from some kilometers
44:44down circulating through the surface and then sinking back down again it is very difficult to
44:51breathe it's very acidic and very bitter the magma has gases in it as it comes up to the surface
44:58just like when you pour out a bottle of coca-cola the gases come out so what we have here
45:04is
45:04sulfur dioxide hydrogen sulfide water vapor carbon dioxide coming out of the magma before the magma then
45:13cools and sinks down and that's what we're breathing now it's kind of unpleasant
45:22this volcanic phenomenon is a product of immense amounts of primordial heat escaping from inside our
45:29planet
45:32yet we have seen something similar in the far reaches of the solar system
45:40io is the same size as our moon and should be a cold dead world
45:50yet our first glimpses of io revealed it as seething with heat alive with volcanic activity
46:00just one of the many lava lakes on io releases more heat than all earth's volcanoes put together
46:13if we were to stand on the surface of io now what what would be the similarities and what would
46:18the differences the lake would probably appear very very similar to this except for the scale the lava
46:25lakes and io are vastly larger the biggest one we think is 180 kilometers in diameter 180 kilometers so
46:32that stretch way obviously way beyond the horizon on earth yeah it's almost beyond description to see
46:38something that size and it's just this huge pool of of of molten molten lava
46:48is the most volcanic place in the solar system endlessly pumping out heat into the cold vacuum of space
47:03but what's really interesting is that it's so small that it shouldn't be volcanic at all
47:17it was one of the greatest surprises of planetary science when these massive volcanoes were discovered
47:22on io mighty planets like mars has big big volcanoes they're not erupting anymore they haven't erupted for
47:28a long time venus lots of volcanoes there but they haven't been erupted in a long time probably uh and
47:35here we have higher which is just insanely volcanic it's just pumping out vast amounts of energy
47:40in a zone in the part of the solar system where it was thought that everything was dead
47:52everything we now know about iron comes from looking at it from a distance
47:57but measuring the heat pumping out of this lava lake will give us a better idea of the true scale
48:03of the
48:04heat loss on ion far from being a benign bubbling cauldron this volcano has the power to kick off at
48:15a moment's notice
48:20i can just see pieces of molten rock rising up just below my chin
48:25and with it a cloud of heat absolutely overpowering heat there must be a hell of an eruption going on
48:39seeing active volcanism like this on such a small moon like io changed our view of the workings of the
48:46solar system
48:49a world like io having such a powerful internal heat source cries out for an explanation see io is far
48:57too
48:58small a world to have retained any internal heat to have the same heat source that powers
49:06that powers the earth's volcanoes so something else must be driving that powerful volcanism on io
49:19new images sent back from recent space probes confirm that io is a surprising and bizarre world
49:31being so far from the sun io's surface is mostly very cold it's covered in frozen sulfur which gives it
49:40its yellow color
49:44yet io is pot marked by cauldrons of molten lava
49:51you know i think it is remarkable and fortunate in a sense that you can come to a place like
49:58this on
49:58our planet and just get the tiniest sense of what it must be like to stand on the edge of
50:06one of those
50:07magnificent lava lakes on io
50:13when we first saw hot volcanic action on io
50:16it was quite a surprise for most planetary scientists
50:20but by considering simple laws of physics it didn't surprise everyone
50:26just weeks before voyager arrived at jupiter three scientists made a prediction and it was
50:32one of those predictions that when you see it is almost obvious it was used in physics that have been
50:39known for hundreds of years but nobody thought of it they predicted that io should have an intense
50:46internal heat source because of its unique position in the solar system
50:50very close to a giant planet and surrounded by other large moons
50:56in the solar system in the solar system in the solar system in the solar system
51:00i o sits about the same distance from jupiter as our own moon does from earth
51:07but don't forget that orbiting outside io are its sister moons europa and ganymede
51:15i o is under the influence not just of the massive gravitational pull of jupiter
51:20but also the additional pull of its neighboring moons
51:25it's this gravitational tug of war that conspires to breathe life into io
51:33now io has a very interesting relationship with europa and ganymede because for every
51:39four orbits that io makes around the planet europa goes around almost exactly twice and ganymede goes
51:50around just once periodically they line up together bang bang bang and io gets a powerful gravitational kick
52:00on a very regular basis and that has the effect of moving io out of a nice circular orbit
52:08into an elliptical or an eccentric orbit io comes close to jupiter and then far away from jupiter
52:16and then close to jupiter again because jupiter's gravity is so big that has the effect of stretching
52:23and squashing io imagine it was a squash ball if you stretch and squash and stretch and squash
52:29and it gets hot by friction and the same thing happens to this moon the power of the gravitational
52:35interaction between jupiter and io is extraordinary it contorts the shape of this tiny moon moving rock
52:43as if it were nothing more than water now this crater is about what 30 meters from the base that
52:53you can
52:54see down there up to the edge of the rim now io when it orbits around jupiter every 1.8
53:01days
53:01flexes by something like 100 meters that's three times the height of that crater remember io's surface
53:10is pretty much like this solid rock so imagine how much energy that takes and all that energy comes from
53:19jupiter's gravitational field and that is the energy that powers the volcanoes
53:36io is a world beyond our imagination its unique gravitational connections provide a seemingly
53:43inexhaustible supply of heat as well as its huge lava lakes the heat also powers the largest volcanic eruptions in
53:53the solar system
53:54so
54:03molten rock and gas blasts out from the frigid surface the gas expands shattering lava into a giant fountain of
54:13fine particles
54:21with weak gravity and a sparse atmosphere io's volcanic plumes can reach 500 kilometers above the moon's surface
54:30the moon's surface
54:50this incredible phenomena bulkanism comes from the simplest of laws of physics the the law that says that
55:00heat contained in a planet must eventually find a way to escape into the coldness of space
55:07but what a spectacular way for the laws of physics to play out
55:13in the most unexpected of places in the coldest reaches of the solar system
55:20the laws of physics created a fiery world of wonder
55:24and io is not alone many of the hundreds of moons in the solar system
55:30are not dead barren and uninteresting worlds but active often violent and always beautiful worlds of wonder
55:47the solar system
55:48io is fascinating it doesn't derive its energy from an internal heat source in the same way that the earth
55:54does
55:55it extracts energy from its orbit around its giant parent planet jupiter and for all those reasons
56:03my own is a wonder of the solar system
56:06my own is a wonder of the earth
56:34wider
56:34orbiting our star has given us valuable insights into the nature of our own world.
56:41Our view of the Earth's place in space has been turned on its head.
56:48Out there are many truly violent and hostile worlds, but they're driven by the same laws
56:57that shape and control our own world. And so, I suppose it's, in many ways, a miracle that we exist
57:09at all.
57:12Our solar system is like a cosmic laboratory. Until we went there, we had no idea of what the laws
57:20of nature could produce.
57:23I think one of the most important lessons that our exploration of the solar system has taught us
57:28is that the laws of nature can create vastly different worlds with the tiniest changes.
57:40We now see how the life and death of planets and moons is governed by interconnections which span the solar
57:49system.
57:50And we wouldn't be here if it wasn't for those connections.
57:57We don't live on a planet isolated from the rest of the solar system, from the rest of the universe.
58:03We live in a place that's intimately connected with everywhere else.
58:19We live in a local landscape.
58:23We live in a place where we live in completely different Beijo sensibles.
58:47We live in a place where you live in a Antrag.
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