1 00:00:03,620 --> 00:00:07,330 Liftoff of Messenger on NASA's mission to Mercury. 2 00:01:05,580 --> 00:01:11,372 Beyond the inner solar system, past the asteroid belt... 3 00:01:11,500 --> 00:01:13,412 ...lies Jupiter. 4 00:01:16,220 --> 00:01:21,056 The largest of the planets is a giant swirling ball of gas... 5 00:01:24,780 --> 00:01:28,091 ...its marbled appearance generated by violent winds 6 00:01:28,220 --> 00:01:30,212 that rage through its clouds. 7 00:01:40,100 --> 00:01:44,458 Jupiter is a world as strange as it is remote. 8 00:01:50,500 --> 00:01:53,379 If you fly upwards only about 100 kilometres or so, 9 00:01:53,500 --> 00:01:56,777 you reach the edge of our atmosphere and the blackness of space - 10 00:01:56,900 --> 00:01:58,300 it's really not that far. 11 00:01:58,420 --> 00:01:59,979 But once you're in space, 12 00:02:00,100 --> 00:02:04,219 the distance scales are incomprehensible. 13 00:02:04,340 --> 00:02:08,175 Venus, the closest planet, is over 40 million kilometres away, 14 00:02:08,300 --> 00:02:11,896 Jupiter around 650 million kilometres. 15 00:02:12,020 --> 00:02:15,616 It takes our fastest spacecraft years to get there. 16 00:02:15,740 --> 00:02:19,211 So the idea that those planets could have any influence 17 00:02:19,340 --> 00:02:22,299 on us here on Earth seems fanciful, 18 00:02:22,420 --> 00:02:27,017 and, indeed, if you're talking about your chances of meeting a handsome stranger, 19 00:02:27,140 --> 00:02:32,454 or your life plans requiring a moderate reconfiguration about a week on Wednesday, 20 00:02:32,580 --> 00:02:34,412 then you would be right. 21 00:02:34,540 --> 00:02:38,659 However, if you ask more profound questions, deeper questions, 22 00:02:38,780 --> 00:02:40,772 like, why is the Earth the way that it is, 23 00:02:40,900 --> 00:02:45,417 why is there life on Earth, why do we exist at all, 24 00:02:45,540 --> 00:02:50,092 then it turns out that the planets, and Jupiter in particular, 25 00:02:50,220 --> 00:02:52,291 have had a profound effect. 26 00:03:08,380 --> 00:03:12,090 Early in its life, the young Jupiter went on the rampage. 27 00:03:20,660 --> 00:03:25,177 The giant planet embarked on a voyage of destruction across the solar system... 28 00:03:26,860 --> 00:03:30,171 ...that transformed the destiny of the planets 29 00:03:30,300 --> 00:03:33,498 and the course of life on Earth. 30 00:03:43,620 --> 00:03:46,340 Jupiter is the godfather of the planets. 31 00:03:48,940 --> 00:03:53,731 Understand it, and you understand how the solar system came to be. 32 00:04:15,460 --> 00:04:19,852 On Earth, we can see glimpses of Jupiter's power 33 00:04:19,980 --> 00:04:24,054 in the scars it's left on the face of the planet. 34 00:04:37,500 --> 00:04:40,538 This is the famous Barringer Meteor Crater in Arizona. 35 00:04:40,660 --> 00:04:43,129 It is about a kilometre across, 36 00:04:43,260 --> 00:04:46,970 170 metres from the rim to the crater floor, 37 00:04:47,100 --> 00:04:50,172 and it was created about 50,000 years ago 38 00:04:50,300 --> 00:04:53,850 when a meteorite 50 metres across 39 00:04:53,980 --> 00:04:58,532 entered the Earth's atmosphere travelling at about 13 kilometres per second. 40 00:04:58,660 --> 00:05:01,653 That means it would have taken around, what, seven seconds 41 00:05:01,780 --> 00:05:03,851 to go from the top of the atmosphere to the ground. 42 00:05:03,980 --> 00:05:06,290 And it hit with such force 43 00:05:06,420 --> 00:05:11,097 that the energy released was equivalent to ten megatons of TNT. 44 00:05:11,220 --> 00:05:14,691 And that is a very large nuclear bomb. 45 00:05:19,140 --> 00:05:21,575 The meteorite that hit the Earth here 46 00:05:21,700 --> 00:05:24,738 is thought to have come from the asteroid belt... 47 00:05:26,060 --> 00:05:27,938 ...the ring of rocky debris 48 00:05:28,060 --> 00:05:30,939 that orbits at the edge of the inner solar system. 49 00:05:34,900 --> 00:05:37,654 And it was deflected from its orbit 50 00:05:37,780 --> 00:05:42,059 most likely by the gravitational influence of Jupiter. 51 00:05:50,460 --> 00:05:54,500 Jupiter is a completely different class of planet to the Earth. 52 00:05:55,900 --> 00:05:57,573 A gas giant. 53 00:05:59,220 --> 00:06:01,655 A swirling ball of hydrogen and helium 54 00:06:01,780 --> 00:06:06,536 so large you could fit 1,300 Earths inside. 55 00:06:12,900 --> 00:06:16,371 Jupiter can exert such a powerful influence on the asteroids 56 00:06:16,500 --> 00:06:17,934 because it's so massive - 57 00:06:18,060 --> 00:06:20,370 it's about two-and-a-half times the mass 58 00:06:20,500 --> 00:06:25,131 of all the other planets, moons and asteroids in the solar system combined, 59 00:06:25,260 --> 00:06:28,298 and therefore it has a strong gravitational pull. 60 00:06:29,420 --> 00:06:32,140 And this means that Jupiter exerts an influence 61 00:06:32,260 --> 00:06:35,810 across the entire solar system that's second only to the Sun. 62 00:06:37,340 --> 00:06:41,129 And that influence does far more than create the odd crater. 63 00:06:41,260 --> 00:06:44,412 It can change the history of worlds. 64 00:06:55,340 --> 00:06:59,619 To understand how Jupiter rose to such dominance, 65 00:06:59,740 --> 00:07:03,654 you have to go back to a time before the solar system even existed. 66 00:07:14,580 --> 00:07:20,258 Nearly five billion years ago, a distant exploding star 67 00:07:20,380 --> 00:07:23,214 sent a shockwave across the galaxy... 68 00:07:32,180 --> 00:07:34,695 ...causing the cloud of gas and dust 69 00:07:34,820 --> 00:07:38,291 that would become our solar system to collapse... 70 00:07:40,420 --> 00:07:42,730 ...as the Sun began to form. 71 00:07:51,660 --> 00:07:55,654 But further out, something else was growing. 72 00:08:02,220 --> 00:08:04,371 After 50 million years... 73 00:08:06,460 --> 00:08:08,929 ...the Sun's nuclear furnace ignited... 74 00:08:20,140 --> 00:08:25,090 ...the light of its first dawn revealing Jupiter... 75 00:08:26,620 --> 00:08:29,260 ...the solar system's first world. 76 00:08:33,500 --> 00:08:35,332 A planet born so early, 77 00:08:35,460 --> 00:08:39,852 it swept up most of the material left over from the formation of the Sun. 78 00:08:47,060 --> 00:08:50,292 Because of its dominance, Jupiter had a profound effect 79 00:08:50,420 --> 00:08:52,889 on the newly forming solar system, 80 00:08:53,020 --> 00:08:56,491 and paved the way for our living world to form. 81 00:09:00,460 --> 00:09:02,770 This is a model of our solar system. 82 00:09:02,900 --> 00:09:06,940 So here's the Sun, and then we have the four inner rocky planets - 83 00:09:07,060 --> 00:09:12,180 Mercury, Venus, Earth and Mars. 84 00:09:12,300 --> 00:09:14,769 Then comes the asteroid belt, 85 00:09:14,900 --> 00:09:21,773 the ring of millions of small pieces of rock orbiting around the Sun. 86 00:09:21,900 --> 00:09:27,976 And then the gas giants - Jupiter, Saturn, Uranus and Neptune. 87 00:09:28,100 --> 00:09:31,776 Now this has a sort of pleasing regular structure about it, 88 00:09:31,900 --> 00:09:35,780 all the rocky planets close to the star, and the gas giants further out, 89 00:09:35,900 --> 00:09:39,974 and we thought this must be the natural order of things, 90 00:09:40,100 --> 00:09:43,138 the way that solar systems have to form, 91 00:09:43,260 --> 00:09:47,220 until we started to detect planets around distant stars, 92 00:09:47,340 --> 00:09:52,369 and then we found that this arrangement is not typical at all. 93 00:09:57,140 --> 00:10:02,818 Our sun is just one of around 300 billion stars in our galaxy. 94 00:10:06,140 --> 00:10:10,851 And almost every one of those stars is home to its own system of planets. 95 00:10:15,260 --> 00:10:21,291 In most other systems, the region where our planet orbits is empty. 96 00:10:24,380 --> 00:10:28,977 Instead, closer to the star, we see super-Earths - 97 00:10:29,100 --> 00:10:32,855 vast rocky planets many times bigger than our own. 98 00:10:36,940 --> 00:10:42,174 But, crucially, these worlds are thought to have thick, toxic atmospheres, 99 00:10:42,300 --> 00:10:45,896 making them completely inhospitable to life. 100 00:10:51,060 --> 00:10:53,780 And that raises a very interesting question - 101 00:10:53,900 --> 00:10:58,292 why, then, is our solar system the way that it is? 102 00:11:06,980 --> 00:11:08,539 To answer that question, 103 00:11:08,660 --> 00:11:11,414 we've sent spacecraft to every one of the planets. 104 00:11:13,380 --> 00:11:16,179 And they've uncovered strange anomalies 105 00:11:16,300 --> 00:11:19,020 that reveal our solar system's past. 106 00:11:22,460 --> 00:11:26,340 Our missions to Venus found that it once had far more water 107 00:11:26,460 --> 00:11:30,773 than you'd expect for a planet so close to the Sun, 108 00:11:30,900 --> 00:11:33,699 just as Earth does today. 109 00:11:38,460 --> 00:11:43,012 The spacecraft we've sent to Mars touched down on a world that is, 110 00:11:43,140 --> 00:11:48,260 curiously, just half the size of her sister planets, Earth and Venus. 111 00:11:54,500 --> 00:11:56,093 And in the asteroid belt, 112 00:11:56,220 --> 00:11:59,896 we've uncovered a graveyard of failed worlds, 113 00:12:00,020 --> 00:12:03,855 their growth mysteriously cut short. 114 00:12:13,780 --> 00:12:15,578 To cause all these anomalies, 115 00:12:15,700 --> 00:12:19,330 it's thought something catastrophic must have happened 116 00:12:19,460 --> 00:12:22,498 very early in the solar system's history. 117 00:12:25,180 --> 00:12:28,969 All the evidence suggests that around 4.5 billion years ago, 118 00:12:29,100 --> 00:12:31,296 Jupiter's orbit began to change, 119 00:12:31,420 --> 00:12:34,015 triggering a period of unprecedented violence 120 00:12:34,140 --> 00:12:37,816 which completely transformed the face of the young solar system, 121 00:12:37,940 --> 00:12:40,933 and we know this because the marauding planet 122 00:12:41,060 --> 00:12:43,655 left a trail of destruction in its wake. 123 00:12:51,180 --> 00:12:56,130 Early in its life, Jupiter began to move inwards towards the Sun. 124 00:12:59,580 --> 00:13:03,176 And the effects of that journey can be seen to this day. 125 00:13:13,380 --> 00:13:18,216 In between the orbits of Mars and Jupiter lies the asteroid belt... 126 00:13:21,620 --> 00:13:23,577 ...a desolate wasteland of debris 127 00:13:23,700 --> 00:13:26,977 left over from the beginning of the solar system. 128 00:13:36,380 --> 00:13:40,613 Rocky bodies too small to be planets in their own right. 129 00:13:56,740 --> 00:13:58,379 In science-fiction films, 130 00:13:58,500 --> 00:14:02,210 the asteroid belt is often depicted as an un-navigable mass 131 00:14:02,340 --> 00:14:04,775 of tumbling rubble, but it's not like that at all. 132 00:14:04,900 --> 00:14:08,052 So much so, in fact, that modern spacecraft engineers 133 00:14:08,180 --> 00:14:12,299 can fly a spacecraft through without making any course corrections. 134 00:14:12,420 --> 00:14:15,618 And the reason for that is, there's not much mass in the asteroid belt. 135 00:14:15,740 --> 00:14:20,098 The sum total of all of them is only about 4% the mass of the Moon, 136 00:14:20,220 --> 00:14:24,976 and they're spread out in a huge ring out beyond the orbit of Mars. 137 00:14:25,100 --> 00:14:26,819 It's a vast amount of space. 138 00:14:26,940 --> 00:14:30,934 That means that the average distance between any two large asteroids 139 00:14:31,060 --> 00:14:35,054 is about eight times the distance between the Earth and the Moon. 140 00:14:35,180 --> 00:14:39,379 So I could stand on one of those large asteroids and look out into space 141 00:14:39,500 --> 00:14:43,813 and my nearest neighbour would just be a dim star in the dark. 142 00:14:48,380 --> 00:14:50,497 But scattered amongst the rubble 143 00:14:50,620 --> 00:14:53,738 are objects that are far more than mere rocks. 144 00:14:54,860 --> 00:15:00,652 Five, four, three, two, main engines start, one, 145 00:15:00,780 --> 00:15:03,978 zero, and liftoff of the Delta II rocket with Dawn. 146 00:15:05,700 --> 00:15:08,534 In 2007, NASA's Dawn Mission 147 00:15:08,660 --> 00:15:12,893 was sent to explore the two largest objects in the asteroid belt. 148 00:15:34,660 --> 00:15:39,018 After a year in orbit around the giant asteroid Vesta... 149 00:15:44,220 --> 00:15:46,815 ...in March 2015, 150 00:15:46,940 --> 00:15:50,377 Dawn made its final approach on a body so large 151 00:15:50,500 --> 00:15:54,779 it makes up almost a third of the mass of the entire asteroid belt. 152 00:15:57,740 --> 00:15:59,220 Ceres. 153 00:16:22,060 --> 00:16:25,371 On arrival, the first images Dawn sent back to Earth 154 00:16:25,500 --> 00:16:28,618 contained something entirely unexpected. 155 00:16:36,300 --> 00:16:38,337 Mysterious bright patches 156 00:16:38,460 --> 00:16:41,134 in one of Ceres's largest craters. 157 00:16:50,940 --> 00:16:55,253 Spectral analysis of the images showed the patches were, in fact, 158 00:16:55,380 --> 00:16:59,738 the salty residue left behind by liquid water... 159 00:17:02,340 --> 00:17:06,812 ...suggesting there must be large amounts of ice just beneath the crust. 160 00:17:16,380 --> 00:17:21,580 Dawn went on to discover over 300 bright spots all over the surface. 161 00:17:26,620 --> 00:17:29,260 And this means that beneath its thin crust, 162 00:17:29,380 --> 00:17:34,819 Ceres has a thick, ice-rich mantle surrounding its rocky core... 163 00:17:38,460 --> 00:17:42,773 ...evidence that the dwarf planet is made up of multiple layers. 164 00:17:56,660 --> 00:18:01,291 The interior of Ceres is like nothing else in the asteroid belt. 165 00:18:01,420 --> 00:18:04,333 The differentiation, that separation into layers, 166 00:18:04,460 --> 00:18:09,171 observed by Dawn is more characteristic of a planet than an asteroid. 167 00:18:09,300 --> 00:18:11,496 So, 4.5 billion years ago, 168 00:18:11,620 --> 00:18:16,058 Ceres was well on its way to becoming a fully fledged world. 169 00:18:28,300 --> 00:18:32,453 It's thought that, in its infancy, Ceres was very different. 170 00:18:36,380 --> 00:18:40,932 The water that now lies frozen within its interior was once liquid. 171 00:18:45,660 --> 00:18:48,095 Protected beneath a thin layer of ice... 172 00:18:50,300 --> 00:18:54,340 ...Ceres was once covered by a deep saltwater ocean. 173 00:19:12,500 --> 00:19:15,015 Before Ceres had reached its full potential, 174 00:19:15,140 --> 00:19:17,291 a great disturbance sent shockwaves through 175 00:19:17,420 --> 00:19:19,651 what would one day become the asteroid belt 176 00:19:19,780 --> 00:19:21,737 and cut its development short. 177 00:19:34,460 --> 00:19:38,249 As Jupiter circled the young sun, it started to clear a path 178 00:19:38,380 --> 00:19:42,533 through the gas and dust that shrouded the early solar system. 179 00:19:48,860 --> 00:19:52,376 But that process caused it to do something alarming. 180 00:19:55,060 --> 00:19:57,700 Gravitational interactions with the gas 181 00:19:57,820 --> 00:20:01,257 made the giant planet spiral inwards towards the sun... 182 00:20:04,300 --> 00:20:06,656 ...ploughing straight through the region of space 183 00:20:06,780 --> 00:20:09,249 that would become the asteroid belt... 184 00:20:11,220 --> 00:20:15,294 ...scattering the material from which Ceres would otherwise have grown. 185 00:20:22,020 --> 00:20:24,580 Computer simulations of the early solar system 186 00:20:24,700 --> 00:20:28,216 suggest that the asteroid belt once contained enough material 187 00:20:28,340 --> 00:20:30,980 to build a planet the size of the Earth, 188 00:20:31,100 --> 00:20:34,093 and perhaps that was Ceres's destiny. 189 00:20:34,220 --> 00:20:41,297 But when Jupiter passed through, it scattered 99.9% of the material away, 190 00:20:41,420 --> 00:20:43,980 and Ceres's fate was sealed. 191 00:20:49,940 --> 00:20:54,014 Within 100 million years, Ceres's ocean froze 192 00:20:54,140 --> 00:20:56,416 and was buried beneath its crust... 193 00:21:00,300 --> 00:21:03,338 ...the young planet's development cut short 194 00:21:03,460 --> 00:21:05,929 before it could fulfil its promise. 195 00:21:18,540 --> 00:21:21,738 But Jupiter's reign of terror was far from over. 196 00:21:28,820 --> 00:21:31,176 It would continue its journey inwards 197 00:21:31,300 --> 00:21:34,213 towards the place our planet was beginning to form... 198 00:21:36,860 --> 00:21:39,659 ...threatening the very existence of Earth. 199 00:21:45,140 --> 00:21:48,929 Jupiter had such an overwhelming effect on the young solar system 200 00:21:49,060 --> 00:21:52,292 because of its powerful gravitational field... 201 00:22:11,340 --> 00:22:14,538 ...the effects of which we can still witness today. 202 00:23:09,140 --> 00:23:12,212 Jupiter exerts its influence across the solar system 203 00:23:12,340 --> 00:23:13,820 through its gravitational field... 204 00:23:22,900 --> 00:23:26,132 ...which is by far the most powerful of all the planets', 205 00:23:26,260 --> 00:23:29,139 because Jupiter is the most massive of all the planets - 206 00:23:29,260 --> 00:23:33,140 it's about 320 times the mass of the Earth. 207 00:23:33,260 --> 00:23:36,014 That's why it was so destructive in the past. 208 00:23:36,140 --> 00:23:39,690 And we see the power of that gravitational field today 209 00:23:39,820 --> 00:23:44,815 in its influence on the closest of Jupiter's largest moons, Io. 210 00:23:58,260 --> 00:24:01,537 Io is the most volcanic world in the solar system... 211 00:24:06,700 --> 00:24:10,535 ...its surface covered with hundreds of active volcanoes... 212 00:24:16,020 --> 00:24:18,251 ...and lakes of molten lava. 213 00:24:24,260 --> 00:24:27,332 The largest, known as Loki Patera, 214 00:24:27,460 --> 00:24:30,658 is more than 200 kilometres in diameter... 215 00:24:39,620 --> 00:24:43,500 ...a million times the area of any lava lake on Earth... 216 00:24:45,340 --> 00:24:48,936 ...its surface tormented by waves of molten rock. 217 00:25:01,820 --> 00:25:03,777 Io is a vision of hell... 218 00:25:09,380 --> 00:25:12,930 ...created by the Moon's proximity to Jupiter. 219 00:25:32,020 --> 00:25:33,659 Volcanism here on Earth 220 00:25:33,780 --> 00:25:37,774 is powered by the internal heat down below the surface. 221 00:25:37,900 --> 00:25:42,053 Now, much of that is residual heat left over from the Earth's formation 222 00:25:42,180 --> 00:25:44,695 4.5 billion years ago - about half of it - 223 00:25:44,820 --> 00:25:49,497 and the other half is down to radioactive decay of elements around the Earth's core. 224 00:25:51,020 --> 00:25:53,410 Now, on Io, it's different. 225 00:25:53,540 --> 00:25:58,774 Io is a much smaller world and so it didn't retain much residual heat, 226 00:25:58,900 --> 00:26:02,655 so there the volcanoes are powered by a different process. 227 00:26:02,780 --> 00:26:04,612 It's known as tidal heating. 228 00:26:11,820 --> 00:26:14,574 The energy that drives Io's volcanism 229 00:26:14,700 --> 00:26:17,499 doesn't come from heat stored within the Moon. 230 00:26:20,940 --> 00:26:22,772 It's generated by gravity... 231 00:26:25,700 --> 00:26:29,455 ...because Io orbits just 350,000 kilometres 232 00:26:29,580 --> 00:26:32,573 from the tops of Jupiter's clouds. 233 00:26:48,780 --> 00:26:52,490 Io orbits at about the same distance from Jupiter 234 00:26:52,620 --> 00:26:54,771 as our moon orbits the Earth, 235 00:26:54,900 --> 00:26:57,256 but because Jupiter is so much more massive, 236 00:26:57,380 --> 00:26:58,860 Io goes around much more quickly. 237 00:26:58,980 --> 00:27:02,212 In fact, it goes around once every 42 hours. 238 00:27:02,340 --> 00:27:06,732 Now, if Io were Jupiter's only moon, that orbit would be circular. 239 00:27:06,860 --> 00:27:08,135 But it isn't. 240 00:27:11,980 --> 00:27:15,576 The next moon out, Europa, goes round Jupiter 241 00:27:15,700 --> 00:27:18,932 precisely once for every two orbits of Io... 242 00:27:23,220 --> 00:27:28,420 ...which means that every second orbit, Io and Europa fall into alignment. 243 00:27:30,300 --> 00:27:33,179 It's what's known as an orbital resonance. 244 00:27:35,180 --> 00:27:37,695 That gives it a gravitational kick, 245 00:27:37,820 --> 00:27:40,733 and that moves Io's orbit into an ellipse. 246 00:27:40,860 --> 00:27:43,580 Now, that means that the gravitational forces on Io 247 00:27:43,700 --> 00:27:46,659 are constantly shifting and changing, 248 00:27:46,780 --> 00:27:49,375 and that stretches and squashes the moon 249 00:27:49,500 --> 00:27:52,095 and heats it up by friction, 250 00:27:52,220 --> 00:27:54,257 and that is called tidal heating, 251 00:27:54,380 --> 00:27:57,896 and that is the origin of Io's volcanoes. 252 00:28:10,220 --> 00:28:13,770 This process raises the temperature in Io's interior - 253 00:28:13,900 --> 00:28:16,699 which would otherwise be frozen solid - 254 00:28:16,820 --> 00:28:19,654 to more than 1,000 degrees Celsius... 255 00:28:21,900 --> 00:28:23,539 ...creating its lava lakes... 256 00:28:27,020 --> 00:28:29,694 ...and powering immense volcanic plumes... 257 00:28:32,660 --> 00:28:36,813 ...that rise up to 300 kilometres from the moon's surface... 258 00:28:38,340 --> 00:28:39,933 ...and out into space. 259 00:28:45,100 --> 00:28:48,810 Io provides the solar system with a vivid reminder... 260 00:28:50,180 --> 00:28:52,058 ...of the giant planet's power. 261 00:29:06,620 --> 00:29:09,738 Jupiter's intense gravitational field... 262 00:29:11,900 --> 00:29:15,257 ...is the source of Io's volcanism today, 263 00:29:15,380 --> 00:29:18,612 but we don't feel that gravitational pull here on Earth 264 00:29:18,740 --> 00:29:20,971 because Jupiter is so far away. 265 00:29:21,100 --> 00:29:23,535 But 4.5 billion years ago, 266 00:29:23,660 --> 00:29:28,177 Jupiter was migrating inwards towards the inner solar system, 267 00:29:28,300 --> 00:29:32,135 approaching the region where Mars and Earth were forming. 268 00:29:37,940 --> 00:29:41,172 After passing through what would become the asteroid belt... 269 00:29:43,580 --> 00:29:46,300 ...Jupiter entered the inner solar system... 270 00:29:51,100 --> 00:29:54,776 ...continuing its journey spiralling towards the Sun. 271 00:30:02,740 --> 00:30:06,495 Back then, the area where Mars and Earth orbit today 272 00:30:06,620 --> 00:30:09,294 was densely packed with gas and rock. 273 00:30:17,420 --> 00:30:21,937 But as Jupiter approached, it wrought havoc... 274 00:30:23,540 --> 00:30:26,339 ...scattering the rocky material in all directions. 275 00:30:29,580 --> 00:30:32,140 Some sent careering into the Sun... 276 00:30:41,260 --> 00:30:44,697 ...others thrown out into interstellar space. 277 00:30:52,180 --> 00:30:56,811 And it's this that may explain our solar system's unusual structure. 278 00:30:59,660 --> 00:31:01,970 Here's the solar system today. The Sun, 279 00:31:02,100 --> 00:31:03,819 the four inner rocky planets, 280 00:31:03,940 --> 00:31:05,659 the asteroids and Jupiter, 281 00:31:05,780 --> 00:31:07,692 and what we think may have happened 282 00:31:07,820 --> 00:31:11,609 is Jupiter made it inwards, through where the asteroids are, 283 00:31:11,740 --> 00:31:14,209 as far in as the orbit of Mars. 284 00:31:14,340 --> 00:31:16,900 Now, that would have cleaned out quite a lot of the material 285 00:31:17,020 --> 00:31:21,412 in the inner solar system, leaving less for the formation of planets. 286 00:31:21,540 --> 00:31:25,329 And that's why we don't see super-Earths in our solar system, 287 00:31:25,460 --> 00:31:31,013 those big, massive rocky worlds that we see in orbit around so many other stars. 288 00:31:31,140 --> 00:31:34,895 This also might explain why Mars is so small. 289 00:31:35,020 --> 00:31:39,094 See, if Jupiter was orbiting in the region that Mars was forming, 290 00:31:39,220 --> 00:31:42,736 there would have been much less material here, and that might explain 291 00:31:42,860 --> 00:31:48,060 why Mars is only a tenth of the mass of Venus and Earth. 292 00:31:58,300 --> 00:32:00,940 Had Jupiter continued to move inwards, 293 00:32:01,060 --> 00:32:03,973 it would have had a similar effect on the Earth... 294 00:32:05,940 --> 00:32:09,536 ...meaning the world we inhabit might never have formed. 295 00:32:16,100 --> 00:32:19,571 But just as it looked like Jupiter would sweep everything away... 296 00:32:20,780 --> 00:32:24,251 ...something stopped the giant planet in its tracks. 297 00:32:31,260 --> 00:32:34,970 Because in the shadows of the outer solar system 298 00:32:35,100 --> 00:32:36,693 another planet was forming. 299 00:32:42,020 --> 00:32:44,580 The solar system's second gas giant... 300 00:32:46,820 --> 00:32:48,095 ...Saturn. 301 00:33:00,580 --> 00:33:03,254 And its birth changed everything. 302 00:33:07,740 --> 00:33:10,812 When a planet forms in a disc of material around a star, 303 00:33:10,940 --> 00:33:13,853 as Jupiter did in our solar system, 304 00:33:13,980 --> 00:33:17,860 it tends to clear out a gap in the disc. 305 00:33:17,980 --> 00:33:21,690 Now, the material tends to fall inwards towards the star - 306 00:33:21,820 --> 00:33:25,700 it's called accretion - and that drags the whole thing inwards, 307 00:33:25,820 --> 00:33:27,857 and that's what happened to Jupiter. 308 00:33:27,980 --> 00:33:31,610 But then a less massive planet, Saturn, 309 00:33:31,740 --> 00:33:36,098 formed further out. It cleared out its own disc 310 00:33:36,220 --> 00:33:39,611 and it too fell inwards towards the Sun, 311 00:33:39,740 --> 00:33:42,335 but more quickly than Jupiter. 312 00:33:42,460 --> 00:33:45,897 That meant that Saturn got into a resonance with Jupiter. 313 00:33:46,020 --> 00:33:51,493 It went round once in orbit around the Sun for every two orbits of Jupiter. 314 00:33:51,620 --> 00:33:57,173 And that has the effect of cleaning out the whole region between the two planets. 315 00:33:57,300 --> 00:34:02,694 And that has the effect, through a series of complicated gravitational interactions, 316 00:34:02,820 --> 00:34:05,335 of slowing and stopping the infall 317 00:34:05,460 --> 00:34:10,057 and eventually causing the two planets to move back out again. 318 00:34:10,180 --> 00:34:15,175 And that is what happened to Jupiter and Saturn in our solar system. 319 00:34:23,460 --> 00:34:26,453 Saturn caused Jupiter to retreat, 320 00:34:26,580 --> 00:34:31,291 leaving behind just enough material from which the inner planets could form. 321 00:34:34,940 --> 00:34:36,135 Mercury. 322 00:34:38,820 --> 00:34:40,334 Venus. 323 00:34:43,300 --> 00:34:44,620 Mars. 324 00:34:50,780 --> 00:34:53,614 And our home, the Earth. 325 00:35:00,300 --> 00:35:03,816 By preventing the formation of much larger super-Earths, 326 00:35:03,940 --> 00:35:06,535 Jupiter allowed our planet to grow. 327 00:35:21,540 --> 00:35:25,216 And even as Jupiter's reign of terror was drawing to a close... 328 00:35:26,620 --> 00:35:31,251 ...it provided one last parting gift to our world. 329 00:35:45,020 --> 00:35:48,696 The young Earth formed in an arid region of the inner solar system. 330 00:35:48,820 --> 00:35:51,619 There was very little water that close to the Sun. 331 00:35:51,740 --> 00:35:53,618 But as the Earth was forming, 332 00:35:53,740 --> 00:35:56,858 Jupiter was already tacking back outwards again 333 00:35:56,980 --> 00:36:01,213 into the outer solar system, through the region that we now call the asteroid belt, 334 00:36:01,340 --> 00:36:06,574 a region populated by many icy, water-rich comets and asteroids. 335 00:36:06,700 --> 00:36:09,534 And they were scattered back inwards again, 336 00:36:09,660 --> 00:36:12,778 bringing water back into the inner solar system. 337 00:36:12,900 --> 00:36:14,971 So I think it is quite a wonderful thought, 338 00:36:15,100 --> 00:36:19,811 that Earth is a water world today because of the motion inwards 339 00:36:19,940 --> 00:36:23,616 and then back outwards again of the massive planet Jupiter. 340 00:36:30,100 --> 00:36:35,698 This idea does seem quite contrived, almost fantastical. 341 00:36:35,820 --> 00:36:39,097 But the more we learn about the formation of solar systems 342 00:36:39,220 --> 00:36:42,736 and the more we try to model a system like ours 343 00:36:42,860 --> 00:36:46,615 with four terrestrial, water-rich planets close to the star 344 00:36:46,740 --> 00:36:48,936 and then the gas giants further out, 345 00:36:49,060 --> 00:36:53,816 the more we learn that perhaps all these things had to happen, 346 00:36:53,940 --> 00:36:57,934 these unlikely movements and interactions between the planets, 347 00:36:58,060 --> 00:37:03,977 in order to produce a system like ours and a planet like ours. 348 00:37:04,100 --> 00:37:08,379 So places like this may be extremely rare. 349 00:37:23,620 --> 00:37:27,011 Today, Jupiter has settled into a regular orbit, 350 00:37:27,140 --> 00:37:30,053 back beyond the far edge of the asteroid belt... 351 00:37:33,180 --> 00:37:37,015 ...its days of marauding through the solar system at an end. 352 00:38:20,620 --> 00:38:25,297 Jupiter has been established in a stable orbit for almost 4 billion years. 353 00:38:25,420 --> 00:38:28,413 If I was to sit here on Earth 3.8 billion years ago, 354 00:38:28,540 --> 00:38:31,453 when life began, and look up into the night sky, 355 00:38:31,580 --> 00:38:34,891 I would have seen it shining there as a point of light, 356 00:38:35,020 --> 00:38:36,852 the same as it looks today, 357 00:38:36,980 --> 00:38:39,449 distant and seemingly detached, 358 00:38:39,580 --> 00:38:42,379 and it's remained that way for the vast expanse of time 359 00:38:42,500 --> 00:38:45,413 it's taken for evolution by natural selection 360 00:38:45,540 --> 00:38:51,172 to transform those first populations of organisms into all this, 361 00:38:51,300 --> 00:38:56,932 to transform the Earth into an oasis of life in the desert of the solar system. 362 00:39:07,260 --> 00:39:10,651 But Jupiter's influence over the Earth remains to this day. 363 00:39:15,780 --> 00:39:19,171 And that's because, despite its great distance from us... 364 00:39:21,020 --> 00:39:24,457 ...it retains a vice-like grip over the asteroid belt. 365 00:39:39,860 --> 00:39:42,853 It's easy, and I think quite natural, to think of the asteroid belt 366 00:39:42,980 --> 00:39:47,179 as a single structure, so a ring of rock surrounding the Sun. 367 00:39:47,300 --> 00:39:49,292 But that's not what it's like at all. 368 00:39:49,420 --> 00:39:53,972 In reality, each one of those millions and millions of pieces of rock 369 00:39:54,100 --> 00:39:56,774 is following its own individual orbit, 370 00:39:56,900 --> 00:40:03,136 and this remarkable animation is made up of ten years of astronomical observations, 371 00:40:03,260 --> 00:40:07,254 and every point you see on this animation 372 00:40:07,380 --> 00:40:12,136 is a single asteroid, apart from all the planets, and so you see 373 00:40:12,260 --> 00:40:15,139 Earth and Mars and Venus whizzing around the Sun, 374 00:40:15,260 --> 00:40:18,936 but the interesting one is Jupiter, 375 00:40:19,060 --> 00:40:22,019 orbiting just outside the asteroid belt. 376 00:40:23,460 --> 00:40:28,740 And what you can see is that the asteroid belt dances to Jupiter's tune. 377 00:40:28,860 --> 00:40:31,329 It's the conductor of the asteroid belt, if you like. 378 00:40:31,460 --> 00:40:33,850 There are complex patterns here, 379 00:40:33,980 --> 00:40:35,733 but there's also structure. 380 00:40:37,660 --> 00:40:41,051 And the reason for that is the delicate interplay 381 00:40:41,180 --> 00:40:43,695 between the gravitational pull of the Sun 382 00:40:43,820 --> 00:40:46,699 and the gravitational force from Jupiter. 383 00:40:48,380 --> 00:40:52,056 Now, what can happen is that, perhaps because of an interaction 384 00:40:52,180 --> 00:40:54,854 between two asteroids - perhaps they collide with each other, 385 00:40:54,980 --> 00:40:58,337 or perhaps on their orbit they line up perfectly with Jupiter 386 00:40:58,460 --> 00:41:00,338 and get an extra gravitational kick - 387 00:41:00,460 --> 00:41:03,532 those asteroids can be disturbed from this structure 388 00:41:03,660 --> 00:41:06,220 and be sent inwards to the inner solar system. 389 00:41:06,340 --> 00:41:08,172 And by that mechanism, 390 00:41:08,300 --> 00:41:14,092 Jupiter has a profound influence on the planets closer to the Sun. 391 00:41:23,940 --> 00:41:25,932 Around 100 million years ago, 392 00:41:26,060 --> 00:41:30,976 an asteroid ten kilometres across was ejected from the asteroid belt. 393 00:41:35,900 --> 00:41:38,131 Dislodged by Jupiter's gravity, 394 00:41:38,260 --> 00:41:41,776 it was set on a collision course with the Earth. 395 00:42:00,460 --> 00:42:04,852 When it struck, it generated a fireball so hot, 396 00:42:04,980 --> 00:42:10,374 anything within a 1,000-kilometre radius would have died instantly. 397 00:42:18,740 --> 00:42:24,498 The impact threw 300 billion tonnes of sulphur into the atmosphere. 398 00:42:33,020 --> 00:42:36,218 And during the nuclear winter that followed, 399 00:42:36,340 --> 00:42:41,415 75% of all species were wiped from the face of the Earth. 400 00:42:49,540 --> 00:42:54,740 In one fell swoop, Jupiter changed the course of our planet's history. 401 00:43:06,740 --> 00:43:09,414 There are a few places on Earth today 402 00:43:09,540 --> 00:43:12,578 where you can catch a glimpse of lost worlds - 403 00:43:12,700 --> 00:43:16,455 you can see Earth as it was millions of years in the past 404 00:43:16,580 --> 00:43:19,857 and perhaps glimpse the Earth as it might have been. 405 00:43:19,980 --> 00:43:21,539 And this is one of them. 406 00:43:21,660 --> 00:43:25,620 Today, this is the Colorado Plain, over a kilometre in altitude, 407 00:43:25,740 --> 00:43:28,699 south of Denver, close to the Rocky Mountains. 408 00:43:28,820 --> 00:43:32,416 But 200 million years ago, this was at sea level. 409 00:43:32,540 --> 00:43:37,376 It was an ancient lake, and the ghosts of those lost worlds, 410 00:43:37,500 --> 00:43:40,060 the imprint of the past, can be seen over there, 411 00:43:40,180 --> 00:43:44,652 because there are literally thousands of dinosaur footprints. 412 00:44:10,420 --> 00:44:13,413 And here they are - the dinosaur footprints. 413 00:44:13,540 --> 00:44:16,260 I find this absolutely remarkable. 414 00:44:16,380 --> 00:44:19,214 This is the footprint of a sauropod dinosaur - 415 00:44:19,340 --> 00:44:22,970 that's one of the big ones, the big herbivores with the long necks. 416 00:44:23,100 --> 00:44:25,899 This animal would have weighed about 30 tonnes. 417 00:44:26,020 --> 00:44:29,411 It was tall enough to peer over a two-storey house. 418 00:44:29,540 --> 00:44:33,090 And what happened here is probably a herd of them, a group of them, 419 00:44:33,220 --> 00:44:36,452 came lumbering across this lake bed. 420 00:44:36,580 --> 00:44:38,970 And then, perhaps that same afternoon, 421 00:44:39,100 --> 00:44:41,934 predators came, maybe following the herd. 422 00:44:42,060 --> 00:44:44,655 And that's these footprints here - 423 00:44:44,780 --> 00:44:47,932 the allosaurs, these three-toed footprints. 424 00:44:48,060 --> 00:44:51,292 A much smaller animal, maybe about twice the height of me, 425 00:44:51,420 --> 00:44:53,810 about two tonnes, very nimble and agile. 426 00:44:53,940 --> 00:44:59,174 And so you see a whole story played out here, frozen in time. 427 00:45:13,380 --> 00:45:16,578 Today, just their traces remain. 428 00:45:21,660 --> 00:45:23,253 But were it not for Jupiter... 429 00:45:25,300 --> 00:45:27,417 ...they might still be here. 430 00:45:44,700 --> 00:45:46,578 There are so many chance events, 431 00:45:46,700 --> 00:45:49,454 not only throughout the history of Earth, 432 00:45:49,580 --> 00:45:53,460 but also spanning the entire history of the universe for 13.8 billion years, 433 00:45:53,580 --> 00:45:56,175 without which we wouldn't exist. 434 00:45:56,300 --> 00:45:58,132 There's an unbroken chain of life 435 00:45:58,260 --> 00:46:00,855 stretching back 4 billion years here on this planet. 436 00:46:00,980 --> 00:46:06,135 You interrupt or interject at any point, and life on Earth is different. 437 00:46:06,260 --> 00:46:10,413 But having said that, there are major events that affected life, 438 00:46:10,540 --> 00:46:13,772 and one of them is the asteroid that wiped out the dinosaurs. 439 00:46:13,900 --> 00:46:18,736 And in that sense, it is certainly true to say that without Jupiter, 440 00:46:18,860 --> 00:46:20,340 we wouldn't be here. 441 00:46:36,980 --> 00:46:41,577 The godfather of the planets paved the way for us to inherit the Earth. 442 00:46:47,420 --> 00:46:51,812 And although it occasionally flings rocks from the asteroid belt our way, 443 00:46:51,940 --> 00:46:54,819 it also protects us. 444 00:47:01,260 --> 00:47:03,536 Because for objects heading towards the Earth 445 00:47:03,660 --> 00:47:06,334 from the far reaches of the solar system, 446 00:47:06,460 --> 00:47:10,454 Jupiter's gravitational field acts as a shield. 447 00:47:15,660 --> 00:47:21,418 Around a century ago, a lump of rock and ice four kilometres across 448 00:47:21,540 --> 00:47:24,260 and weighing 17 billion tonnes... 449 00:47:26,020 --> 00:47:28,580 ...was hurtling towards the inner solar system. 450 00:47:33,620 --> 00:47:36,419 Until Jupiter intervened. 451 00:47:39,540 --> 00:47:44,410 Five, four, three, two, one. 452 00:47:44,540 --> 00:47:46,975 We have ignition and liftoff of Atlantis 453 00:47:47,100 --> 00:47:50,696 and the Galileo spacecraft bound for Jupiter. 454 00:47:50,820 --> 00:47:52,573 70 years later, 455 00:47:52,700 --> 00:47:56,535 we witnessed just how effective a shield Jupiter can be... 456 00:48:06,260 --> 00:48:11,938 ...on board the Space Shuttle Atlantis, the Galileo orbiter. 457 00:48:21,300 --> 00:48:23,656 Three years after Galileo launched, 458 00:48:23,780 --> 00:48:28,093 comet Shoemaker-Levy 9 had been captured by Jupiter's gravity. 459 00:48:37,940 --> 00:48:40,694 Locked in the giant planet's embrace... 460 00:48:43,020 --> 00:48:45,854 ...tidal forces now began to tear it apart. 461 00:48:53,460 --> 00:48:55,611 Its journey cut short, 462 00:48:55,740 --> 00:48:58,300 the comet now faced annihilation. 463 00:49:10,060 --> 00:49:12,291 After crossing the inner solar system, 464 00:49:12,420 --> 00:49:15,572 Galileo passed through the asteroid belt... 465 00:49:19,060 --> 00:49:23,293 ...approaching the spot from where it would witness the comet's final moments. 466 00:49:33,660 --> 00:49:39,054 On July 16th, Galileo saw the first fragments of the comet 467 00:49:39,180 --> 00:49:41,615 enter Jupiter's southern hemisphere. 468 00:49:54,100 --> 00:49:56,171 Pieces of Comet Shoemaker-Levy 9 469 00:49:56,300 --> 00:49:59,054 struck Jupiter over the course of six days. 470 00:50:03,660 --> 00:50:08,098 It was the first time a comet strike had ever been witnessed. 471 00:50:28,540 --> 00:50:30,497 The most destructive impact 472 00:50:30,620 --> 00:50:34,899 released energy equivalent to 6 million megatons of TNT... 473 00:50:37,020 --> 00:50:42,095 ...leaving behind a giant dark cloud 12,000 kilometres across. 474 00:50:51,500 --> 00:50:55,779 By capturing objects and incinerating them on impact, 475 00:50:55,900 --> 00:50:59,689 Jupiter sweeps up bodies from the outer solar system 476 00:50:59,820 --> 00:51:02,540 that might otherwise collide with Earth. 477 00:51:16,140 --> 00:51:20,498 Jupiter, the oldest and largest of the planets, 478 00:51:20,620 --> 00:51:23,419 is the godfather of our solar system. 479 00:51:27,580 --> 00:51:31,176 In youth, it went on the rampage. 480 00:51:39,980 --> 00:51:43,018 For some young planets, it spelled disaster. 481 00:51:48,300 --> 00:51:50,974 But for others, like our own world, 482 00:51:51,100 --> 00:51:53,979 it cleared the way for their formation. 483 00:52:02,140 --> 00:52:06,692 And in adulthood, it created the conditions that allowed us to rise. 484 00:52:11,580 --> 00:52:14,732 So we owe Jupiter a great debt. 485 00:52:16,460 --> 00:52:19,532 But as the dinosaurs found to their cost, 486 00:52:19,660 --> 00:52:23,415 it's a debt that could be recalled at any time. 487 00:52:28,460 --> 00:52:29,689 To the naked eye, 488 00:52:29,820 --> 00:52:32,858 Jupiter's one of the brightest points of light in the night sky, 489 00:52:32,980 --> 00:52:36,894 and through a small telescope it is a beautiful banded world. 490 00:52:37,020 --> 00:52:39,979 But it feels distant, eternal, 491 00:52:40,100 --> 00:52:43,616 disconnected from events here on Earth. 492 00:52:43,740 --> 00:52:47,017 But the more we've understood about the history of the solar system, 493 00:52:47,140 --> 00:52:49,974 the more we've come to understand that that is not the case. 494 00:52:50,100 --> 00:52:54,538 Jupiter has played an important and perhaps decisive role 495 00:52:54,660 --> 00:52:58,051 in the stories of all the planets, including Earth. 496 00:52:58,180 --> 00:53:00,217 You see, the solar system is just that. 497 00:53:00,340 --> 00:53:05,415 It's a system - complex, interconnected and interdependent. 498 00:53:05,540 --> 00:53:11,172 So next time you see Jupiter, just hold your gaze, maybe think for a minute, 499 00:53:11,300 --> 00:53:15,340 because it is so much more than just a point of light, 500 00:53:15,460 --> 00:53:16,814 or a planet, even. 501 00:53:16,940 --> 00:53:20,172 It is the great sculptor of the solar system. 502 00:53:20,300 --> 00:53:23,338 The destroyer and creator of worlds. 503 00:54:04,820 --> 00:54:07,892 I think people are drawn in by Jupiter 504 00:54:08,020 --> 00:54:09,932 because it's very mysterious, 505 00:54:10,060 --> 00:54:13,053 it's covered by clouds that hide what's underneath. 506 00:54:13,180 --> 00:54:14,500 It's very violent. 507 00:54:16,300 --> 00:54:18,531 And it's very intimidating. 508 00:54:20,380 --> 00:54:23,259 It's also very beautiful. 509 00:54:23,380 --> 00:54:27,977 It has all these things going on, and it's hard not to be taken in. 510 00:54:28,100 --> 00:54:32,936 T minus ten, nine, eight, seven, six, five... 511 00:54:33,060 --> 00:54:35,734 Such is Jupiter's mystique, 512 00:54:35,860 --> 00:54:39,774 it's been a recurring target for space exploration. 513 00:54:39,900 --> 00:54:45,373 ...and liftoff, Atlas V with Juno. Trek to Jupiter. 514 00:54:45,500 --> 00:54:50,336 In 2011, NASA launched its latest mission, Juno. 515 00:54:59,660 --> 00:55:02,050 When we launched the Juno spacecraft 516 00:55:02,180 --> 00:55:04,775 away from the Earth, out towards Jupiter, 517 00:55:04,900 --> 00:55:11,010 we didn't have enough speed to get away, out of the gravity of the Sun, 518 00:55:11,140 --> 00:55:13,336 so we actually had to come back to Earth, 519 00:55:13,460 --> 00:55:17,818 get a gravity assist from Earth and then go out to Jupiter. 520 00:55:21,580 --> 00:55:25,813 After travelling for five years, Juno finally arrived. 521 00:55:30,420 --> 00:55:34,209 This is a mission that goes closer to the planet in its orbit 522 00:55:34,340 --> 00:55:35,979 than any other mission ever has, 523 00:55:36,100 --> 00:55:38,934 only a few thousand kilometres from the cloud tops. 524 00:55:39,060 --> 00:55:43,134 And very, very fast - we go from pole to pole in two hours, 525 00:55:43,260 --> 00:55:46,219 slipping between the radiation belts and the cloud tops, 526 00:55:46,340 --> 00:55:49,378 getting the data as fast as we can and getting out. 527 00:55:51,660 --> 00:55:54,698 So in every way, Juno is breaking new ground 528 00:55:54,820 --> 00:55:58,894 and that's allowed us to see things that we couldn't have ever imagined. 529 00:56:03,420 --> 00:56:07,858 Juno's mission is to explore the planet inside and out. 530 00:56:09,900 --> 00:56:12,972 And amongst the many scientific instruments it has on board 531 00:56:13,100 --> 00:56:15,774 is its camera, JunoCam. 532 00:56:18,420 --> 00:56:22,892 You see all these swirls. You see all sorts of spots coming up. 533 00:56:23,020 --> 00:56:24,659 You see all these vortices. 534 00:56:24,780 --> 00:56:28,774 You see dramatic storm systems interacting. 535 00:56:34,380 --> 00:56:39,739 It's mind-blowingly beautiful pictures that this little camera has been taking. 536 00:56:42,900 --> 00:56:46,576 JunoCam was able to see the Great Red Spot from up close. 537 00:56:48,060 --> 00:56:50,211 We can see height to the clouds, 538 00:56:50,340 --> 00:56:52,900 we can see features that look like storms. 539 00:56:53,020 --> 00:56:57,697 Maybe it's hailing or snowing ammonia on Jupiter. 540 00:57:00,740 --> 00:57:05,610 And the most startling thing that we saw from JunoCam's imagery 541 00:57:05,740 --> 00:57:08,733 was that the poles of Jupiter are actually blue. 542 00:57:13,140 --> 00:57:15,780 They're nothing like the orange and white planet 543 00:57:15,900 --> 00:57:18,699 that we grew up thinking about as children. 544 00:57:23,660 --> 00:57:27,449 Juno has just begun to unlock Jupiter's secrets. 545 00:57:30,140 --> 00:57:36,740 And so, at last, the godfather of the planets has begun to talk.