1 00:00:01,969 --> 00:00:04,903 Jupiter is enormous. 2 00:00:04,905 --> 00:00:06,171 Arnou: It's spinal tap. 3 00:00:06,173 --> 00:00:09,274 Everything's turned up a little bit closer to 11. 4 00:00:09,276 --> 00:00:13,145 Jupiter is cool because it's the biggest planet. 5 00:00:13,147 --> 00:00:14,913 And everybody loves 11. 6 00:00:17,785 --> 00:00:20,819 The great red spot, all the vortices going around. 7 00:00:22,323 --> 00:00:25,491 Patel: These storms raging bigger than the earth itself. 8 00:00:25,493 --> 00:00:26,658 And then, the moons. 9 00:00:26,660 --> 00:00:28,794 It's like a little solar system in itself. 10 00:00:28,796 --> 00:00:32,464 79 moons, four big ones. 11 00:00:32,466 --> 00:00:35,467 Io, europa, ganymede, and callisto. 12 00:00:35,469 --> 00:00:38,203 And they are huge. 13 00:00:38,205 --> 00:00:44,343 Each one, their own world of ice, or rock, of volcanoes. 14 00:00:44,345 --> 00:00:46,011 Bolton: You send a spacecraft to jupiter, 15 00:00:46,013 --> 00:00:48,680 You're gonna get fried really quick. 16 00:00:48,682 --> 00:00:51,817 The greeks weren't wrong to make that thing the king of the gods. 17 00:00:51,819 --> 00:00:54,820 -- Captions by vitac -- www.Vitac.Com 18 00:00:54,822 --> 00:00:57,856 Captions paid for by discovery communications 19 00:01:09,103 --> 00:01:11,270 Juno was gonna be the first spacecraft 20 00:01:11,272 --> 00:01:13,272 To fly over the poles of jupiter. 21 00:01:13,274 --> 00:01:18,377 And it was due to arrive on the fourth of July. 22 00:01:18,379 --> 00:01:19,945 Bolton: That day, I had my whole family. 23 00:01:19,947 --> 00:01:22,448 We were going in to jpl. 24 00:01:22,450 --> 00:01:25,117 Then, I remember turning to my kids in the back seat, 25 00:01:25,119 --> 00:01:28,020 And said, "it might not work. Something bad could happen. 26 00:01:28,022 --> 00:01:30,556 Nasa, and the country, and the world 27 00:01:30,558 --> 00:01:32,658 Are taking a big risk, here." 28 00:01:35,429 --> 00:01:38,197 Bagenal: We had no idea what this pole environment was like. 29 00:01:38,199 --> 00:01:40,299 Some sense of the radiation belts. 30 00:01:40,301 --> 00:01:44,903 We knew they are nasty -- really, really nasty. 31 00:01:48,242 --> 00:01:49,541 Bolton: Juno is an armored tank, 32 00:01:49,543 --> 00:01:53,011 But it's nothing compared to jupiter. 33 00:01:53,013 --> 00:01:54,847 Bagenal: So, we want to be really careful. 34 00:01:54,849 --> 00:01:57,716 Go through quickly, and get out. 35 00:01:57,718 --> 00:02:01,253 And so, juno is moving really fast. 36 00:02:01,255 --> 00:02:07,025 Bagenal: It was coming in at about 150,000 miles an hour, 37 00:02:07,027 --> 00:02:12,030 Which is like going around the earth 5 times in 2 hours. 38 00:02:12,032 --> 00:02:14,366 Bolton: Not because we had this incredible propulsion system, 39 00:02:14,368 --> 00:02:17,736 But because jupiter's gravity was sucking us in. 40 00:02:20,007 --> 00:02:22,541 The engineers hoped that it wasn't gonna 41 00:02:22,543 --> 00:02:23,909 Get us completely. 42 00:02:23,911 --> 00:02:26,378 We were gonna just go really close to it. 43 00:02:30,918 --> 00:02:34,052 If it doesn't work, it's over. 44 00:02:34,054 --> 00:02:35,154 Lights off. 45 00:02:39,193 --> 00:02:42,094 Narrator: Long before juno would make its daring attempt, 46 00:02:42,096 --> 00:02:43,462 Scientists realized 47 00:02:43,464 --> 00:02:48,433 Jupiter's region of the solar system was very unusual. 48 00:02:48,435 --> 00:02:52,571 Back in 1955, they detected bursts of radio emission 49 00:02:52,573 --> 00:02:55,741 Coming from jupiter. 50 00:02:55,743 --> 00:02:58,877 This told us that jupiter has a magnetic field, 51 00:02:58,879 --> 00:03:01,647 And perhaps more importantly, a very strong one. 52 00:03:01,649 --> 00:03:03,916 Narrator: Some planets have a dynamo inside, 53 00:03:03,918 --> 00:03:07,619 Surrounding themselves with a magnetic field. 54 00:03:07,621 --> 00:03:10,255 But at this time, the power of these magnetic fields 55 00:03:10,257 --> 00:03:12,424 Wasn't well understood. 56 00:03:12,426 --> 00:03:17,162 Then, in 1958, an experiment around our own planet 57 00:03:17,164 --> 00:03:19,398 Helped scientists start to understand 58 00:03:19,400 --> 00:03:22,601 The mysterious forces at work around jupiter. 59 00:03:22,603 --> 00:03:25,871 At the end of the 1950s, there was a huge push in america 60 00:03:25,873 --> 00:03:28,640 To have a successful satellite in orbit. 61 00:03:28,642 --> 00:03:31,476 And the concept of the explorer 1 mission 62 00:03:31,478 --> 00:03:32,744 Was developed. 63 00:03:32,746 --> 00:03:34,413 Now, the scientific payload for that mission 64 00:03:34,415 --> 00:03:37,082 Was led by a person called "james van allen," 65 00:03:37,084 --> 00:03:40,118 Who had a big interest in magnetic fields 66 00:03:40,120 --> 00:03:42,888 And the particle environments 67 00:03:42,890 --> 00:03:47,092 That might be above our heads, in space. 68 00:03:47,094 --> 00:03:49,895 Lucie: One of the things that he was excited about 69 00:03:49,897 --> 00:03:52,798 Was really high-energy particles. 70 00:03:52,800 --> 00:03:54,866 And so, he proposed an instrument 71 00:03:54,868 --> 00:03:58,570 To be on explorer 1, our very first spacecraft. 72 00:04:06,413 --> 00:04:10,449 So, explorer 1 had a very simple detector system 73 00:04:10,451 --> 00:04:12,618 That would count particles. 74 00:04:12,620 --> 00:04:14,019 Patel: It was a geiger-muller tube, 75 00:04:14,021 --> 00:04:15,587 The kind of thing you look for radiation with. 76 00:04:15,589 --> 00:04:17,356 It counts -- you know, it does the click, click, click, 77 00:04:17,358 --> 00:04:19,358 Counting for radiation. 78 00:04:19,360 --> 00:04:20,826 They wanted to fly this on the rocket, 79 00:04:20,828 --> 00:04:22,828 To measure the radiation up in space. 80 00:04:22,830 --> 00:04:25,264 The experiment was looking for cosmic rays. 81 00:04:25,266 --> 00:04:27,499 Now, cosmic rays are the radiation coming out 82 00:04:27,501 --> 00:04:31,270 From far out in the galaxy, entering our solar system. 83 00:04:31,272 --> 00:04:33,505 And it went up there, counting the particles -- 84 00:04:33,507 --> 00:04:35,641 Zip, zip, zip, zip, going in 85 00:04:35,643 --> 00:04:39,578 At some point, though, the signals disappeared. 86 00:04:39,580 --> 00:04:41,980 Or, aha, you know what's happening? 87 00:04:41,982 --> 00:04:43,548 This is saturated. 88 00:04:43,550 --> 00:04:46,184 The number of particles are so high 89 00:04:46,186 --> 00:04:51,790 That the detector has just said, "I'm gonna shut down." 90 00:04:51,792 --> 00:04:53,759 Lucie: And that realization 91 00:04:53,761 --> 00:04:56,461 Actually led to a phenomenal discovery. 92 00:04:56,463 --> 00:04:59,798 In space, there are doughnut-shaped regions 93 00:04:59,800 --> 00:05:01,266 Around the earth, 94 00:05:01,268 --> 00:05:04,770 Where there are many, many electrically charged particles. 95 00:05:04,772 --> 00:05:08,373 The radiation gets trapped into this really lethal zone 96 00:05:08,375 --> 00:05:10,676 Around the earth. 97 00:05:10,678 --> 00:05:13,245 Lucie: And they're trapped because electrically charged particles 98 00:05:13,247 --> 00:05:16,715 Feel a force from the magnetic field. 99 00:05:16,717 --> 00:05:19,017 Narrator: We had discovered that the earth's magnetic field 100 00:05:19,019 --> 00:05:22,587 Creates a bubble around the planet called a "magnetosphere," 101 00:05:22,589 --> 00:05:24,856 That both deflects charged particles 102 00:05:24,858 --> 00:05:26,958 And captures some, as well. 103 00:05:26,960 --> 00:05:29,394 Critically, many of the radiation particles 104 00:05:29,396 --> 00:05:31,596 Interacting with the magnetosphere 105 00:05:31,598 --> 00:05:33,265 Came streaming from the sun 106 00:05:33,267 --> 00:05:35,967 In what is called "the solar wind." 107 00:05:35,969 --> 00:05:37,736 Lucie: This scientific discovery is, you know, 108 00:05:37,738 --> 00:05:40,372 Fantastic on the one hand, but it's also slightly worrying 109 00:05:40,374 --> 00:05:43,175 Because high-energy charged particles 110 00:05:43,177 --> 00:05:45,610 Can pack a punch when they interact with materials. 111 00:05:45,612 --> 00:05:49,181 So, let's imagine, for example, the impact on the human body. 112 00:05:49,183 --> 00:05:51,383 If these particles have enough energy, 113 00:05:51,385 --> 00:05:53,218 They can penetrate the skin, 114 00:05:53,220 --> 00:05:56,922 And start to interfere with the cells of the body. 115 00:05:56,924 --> 00:05:59,057 Bagenal: And so, we have to be really careful, 116 00:05:59,059 --> 00:06:02,094 Not just because of humans we don't want to be damaged, 117 00:06:02,096 --> 00:06:04,229 But also the electronics. 118 00:06:04,231 --> 00:06:05,664 Narrator: As scientists endeavored 119 00:06:05,666 --> 00:06:08,666 To explore further out into our solar system, 120 00:06:08,668 --> 00:06:10,702 One of the main concerns was whether or not 121 00:06:10,704 --> 00:06:12,304 We could build a spacecraft 122 00:06:12,306 --> 00:06:14,473 That would withstand the harsh radiation 123 00:06:14,475 --> 00:06:16,942 Permeating the solar system. 124 00:06:16,944 --> 00:06:21,780 Lucie: So, can we send a spacecraft to places like jupiter? 125 00:06:21,782 --> 00:06:25,951 Will our spacecraft survive in those kind of environments? 126 00:06:25,953 --> 00:06:27,953 Bolton: When van allen discovered these incredibly 127 00:06:27,955 --> 00:06:30,055 High-energy radiation belts around the earth, 128 00:06:30,057 --> 00:06:32,491 I think people started to then look at the models 129 00:06:32,493 --> 00:06:34,626 Of what would be needed at jupiter. 130 00:06:34,628 --> 00:06:37,095 I mean, our radiation belts, as severe as they are, 131 00:06:37,097 --> 00:06:38,830 And dangerous as they may be, 132 00:06:38,832 --> 00:06:42,033 Are really a piece of cake compared to jupiter. 133 00:06:43,370 --> 00:06:49,441 ♪♪ 134 00:06:49,443 --> 00:06:55,547 ♪♪ 135 00:06:55,549 --> 00:07:00,152 Bagenal: So, the first time we left earth to go out in the solar system 136 00:07:00,154 --> 00:07:04,556 Beyond the orbit of mars, there were major concerns. 137 00:07:04,558 --> 00:07:07,459 "can we send a spacecraft through that environment?" 138 00:07:07,461 --> 00:07:10,195 So, we sent two pioneer spacecraft. 139 00:07:12,032 --> 00:07:15,000 They were pretty crude, with very limited 140 00:07:15,002 --> 00:07:16,968 Computational capabilities, 141 00:07:16,970 --> 00:07:20,872 And very limited power and ability to communicate, 142 00:07:20,874 --> 00:07:23,041 So they would just make a few measurements, 143 00:07:23,043 --> 00:07:25,043 And then send the information back to the earth. 144 00:07:25,045 --> 00:07:26,077 Very simple. 145 00:07:26,079 --> 00:07:34,286 ♪♪ 146 00:07:34,288 --> 00:07:35,454 James: So, when the pioneers 147 00:07:35,456 --> 00:07:38,390 Flew through the magnetosphere of jupiter, 148 00:07:38,392 --> 00:07:40,091 We didn't know how big this was. 149 00:07:40,093 --> 00:07:42,227 We didn't know how large the magnetic field is. 150 00:07:42,229 --> 00:07:43,895 And we didn't know how it was shaped 151 00:07:43,897 --> 00:07:45,997 Or buffeted by the solar wind. 152 00:07:45,999 --> 00:07:50,769 ♪♪ 153 00:07:50,771 --> 00:07:55,474 Narrator: Pioneer 10 flew past jupiter on December 3rd, 1973, 154 00:07:55,476 --> 00:07:58,043 And sent back these incredible images. 155 00:07:58,045 --> 00:08:03,849 ♪♪ 156 00:08:03,851 --> 00:08:06,151 Bolton: Pioneer carried some protection, 157 00:08:06,153 --> 00:08:09,454 But it probably went a little bit closer than it should have, 158 00:08:09,456 --> 00:08:12,190 And in order to try to assess what it was like there, 159 00:08:12,192 --> 00:08:14,659 I mean, it basically was carrying a geiger counter. 160 00:08:14,661 --> 00:08:17,796 And I think everybody was startled at the amount of energy 161 00:08:17,798 --> 00:08:21,199 That we're talking about. 162 00:08:21,201 --> 00:08:23,468 Narrator: During its closest approach to jupiter, 163 00:08:23,470 --> 00:08:27,906 Pioneer 10 absorbed 1,000 times the lethal dose of radiation 164 00:08:27,908 --> 00:08:30,141 For a human being. 165 00:08:30,143 --> 00:08:33,745 Reporter: The spacecraft is collecting its worst radiation exposure now. 166 00:08:33,747 --> 00:08:36,748 Tension is even greater this time, 167 00:08:36,750 --> 00:08:38,350 And so is the relief. 168 00:08:40,387 --> 00:08:44,189 And so, after the pioneers, we knew the extent 169 00:08:44,191 --> 00:08:48,560 Of the jovian magnetosphere, and it is enormous. 170 00:08:54,935 --> 00:08:56,902 Arnou: If we could see it in the night sky, 171 00:08:56,904 --> 00:08:59,571 With jupiter sitting rather far away from us, 172 00:08:59,573 --> 00:09:04,109 It would still be roughly five times larger than the moon. 173 00:09:04,111 --> 00:09:07,112 James: The solar wind that hits that magnetic field 174 00:09:07,114 --> 00:09:12,150 Shapes it like a comet, and produces a long tail. 175 00:09:12,152 --> 00:09:16,488 The tail stretches all the way to saturn. 176 00:09:20,360 --> 00:09:23,995 Bagenal: The primary purpose of those pioneers was really to say, 177 00:09:23,997 --> 00:09:27,132 "can we survive this lethal dose of radiation?" 178 00:09:27,134 --> 00:09:30,368 So then, we can follow with more sophisticated instrumentation 179 00:09:30,370 --> 00:09:32,237 That can do a lot of interesting science. 180 00:09:32,239 --> 00:09:35,373 Narrator: The highly anticipated follow-up mission was voyager. 181 00:09:35,375 --> 00:09:36,708 But before launch, 182 00:09:36,710 --> 00:09:40,011 Scientists realized it might have some design flaws. 183 00:09:40,013 --> 00:09:42,547 Casani: We had the voyager spacecraft down at the cape, 184 00:09:42,549 --> 00:09:45,550 Ready to launch, and it was the pioneer data 185 00:09:45,552 --> 00:09:48,153 That made us realize that the radiation tolerance 186 00:09:48,155 --> 00:09:50,956 That we had designed into the voyager spacecraft 187 00:09:50,958 --> 00:09:53,358 Was not gonna be adequate for the environment 188 00:09:53,360 --> 00:09:55,760 That pioneers 10 and 11 had sent. 189 00:09:55,762 --> 00:09:57,896 It threw us into a real turmoil 190 00:09:57,898 --> 00:10:01,299 Of trying to recover from that. 191 00:10:01,301 --> 00:10:03,802 Bolton: By the time we got to the voyager spacecraft, 192 00:10:03,804 --> 00:10:06,338 We were already so scared and intimidated by jupiter 193 00:10:06,340 --> 00:10:08,406 That we started to move away from it. 194 00:10:08,408 --> 00:10:09,708 We didn't want to get so close, 195 00:10:09,710 --> 00:10:12,110 Because we knew, if you got close, 196 00:10:12,112 --> 00:10:14,145 You're probably spelling the end of the spacecraft. 197 00:10:14,147 --> 00:10:15,580 So, you've got to stay away, 198 00:10:15,582 --> 00:10:18,116 And respect this beast, this monster. 199 00:10:18,118 --> 00:10:20,619 It's much more powerful than we are. 200 00:10:26,760 --> 00:10:30,195 Even with a quite small telescope from your backyard, 201 00:10:30,197 --> 00:10:32,931 You can look up and see jupiter on a clear night. 202 00:10:32,933 --> 00:10:35,033 And you can see the belts and zones. 203 00:10:35,035 --> 00:10:37,035 You can see the red spot. 204 00:10:39,439 --> 00:10:42,240 But voyager saw up close. 205 00:10:46,246 --> 00:10:48,246 And it was really like you were on the spacecraft, 206 00:10:48,248 --> 00:10:49,481 Looking out the window. 207 00:10:51,118 --> 00:10:53,485 Bagenal: You could see these belts and zones, 208 00:10:53,487 --> 00:10:55,920 East west winds going back and forth, 209 00:10:55,922 --> 00:10:57,155 And the great red spot 210 00:10:57,157 --> 00:11:00,892 Being caught up in those belts and zones. 211 00:11:00,894 --> 00:11:04,896 And so, the weather system was becoming clear. 212 00:11:04,898 --> 00:11:07,632 Arnou: As we come in for a close view of jupiter, 213 00:11:07,634 --> 00:11:10,468 You'll see clouds orbiting around the planet 214 00:11:10,470 --> 00:11:13,805 At different rates, with different thickness bands. 215 00:11:13,807 --> 00:11:15,840 And these are called the "jets." 216 00:11:15,842 --> 00:11:19,310 And these jets go around lines of latitude, back and forth, 217 00:11:19,312 --> 00:11:22,814 Some faster than the planet, some slower than the planet. 218 00:11:22,816 --> 00:11:24,883 And so, if you were living on the planet, 219 00:11:24,885 --> 00:11:28,386 There would be these huge shears at different latitudes, 220 00:11:28,388 --> 00:11:32,657 As these fight back and forth in different directions. 221 00:11:32,659 --> 00:11:34,859 Narrator: Finding out what causes this wild weather 222 00:11:34,861 --> 00:11:37,862 Became a key scientific objective. 223 00:11:37,864 --> 00:11:41,766 Arnou: On jupiter, the effects of planetary rotation 224 00:11:41,768 --> 00:11:43,068 Are incredibly important. 225 00:11:43,070 --> 00:11:44,169 Why? 226 00:11:44,171 --> 00:11:46,438 Well, the strength of the rotational forces 227 00:11:46,440 --> 00:11:48,907 Depends on how fast the system rotates, 228 00:11:48,909 --> 00:11:51,976 And it also depends on how big the system is. 229 00:11:51,978 --> 00:11:53,545 And jupiter's huge. 230 00:11:53,547 --> 00:11:57,415 Narrator: Jupiter has a diameter of over 88,000 miles. 231 00:11:57,417 --> 00:12:00,251 It was discovered that it takes just under 10 hours 232 00:12:00,253 --> 00:12:02,520 For the planet to make a complete rotation, 233 00:12:02,522 --> 00:12:05,156 Giving it the shortest day in our solar system. 234 00:12:05,158 --> 00:12:07,959 So, this body is just completely flying. 235 00:12:07,961 --> 00:12:09,861 If you think of the whole planet as a gyroscope, 236 00:12:09,863 --> 00:12:12,330 It would be a very big, very fast gyroscope. 237 00:12:12,332 --> 00:12:16,367 And those gyroscopic effects dominate many of the dynamics 238 00:12:16,369 --> 00:12:18,169 We observe. 239 00:12:18,171 --> 00:12:21,906 We use this demo to explain jupiter's great red spot, 240 00:12:21,908 --> 00:12:24,008 Which is a really interesting phenomenon 241 00:12:24,010 --> 00:12:26,244 That we've observed for over 200 years. 242 00:12:26,246 --> 00:12:28,713 And we think it's existed longer than that. 243 00:12:28,715 --> 00:12:30,815 It's essentially a massive hurricane 244 00:12:30,817 --> 00:12:35,153 That's about 1.3 times the size of the earth. 245 00:12:35,155 --> 00:12:37,822 So, jupiter is a very strongly rotating body, 246 00:12:37,824 --> 00:12:40,125 But it also has a lot of strong turbulence. 247 00:12:40,127 --> 00:12:41,493 And the great red spot 248 00:12:41,495 --> 00:12:47,165 Has formed from this rapidly rotating turbulence. 249 00:12:47,167 --> 00:12:51,069 Narrator: As a cloud of gas or liquid moves across a rotating surface, 250 00:12:51,071 --> 00:12:54,672 Its path begins to curve along with the rotation. 251 00:12:54,674 --> 00:12:56,641 This is called the "coriolis effect," 252 00:12:56,643 --> 00:12:59,177 And it's what spins hurricanes here on earth. 253 00:12:59,179 --> 00:13:02,580 But because jupiter is so large, and turns so fast, 254 00:13:02,582 --> 00:13:05,784 Its weather is far more extreme. 255 00:13:05,786 --> 00:13:07,752 Hawkins: The effect of the coriolis force 256 00:13:07,754 --> 00:13:10,488 In the presence of turbulence acts to generate 257 00:13:10,490 --> 00:13:13,391 Large-scale structures like the great red spot. 258 00:13:13,393 --> 00:13:15,360 And they persist. 259 00:13:15,362 --> 00:13:17,462 Arnou: That's what you get in rotating systems. 260 00:13:17,464 --> 00:13:22,467 You naturally roll things up into large vertical structures. 261 00:13:24,704 --> 00:13:26,504 And they live a long, long time 262 00:13:26,506 --> 00:13:28,439 When the system's rapidly rotating. 263 00:13:28,441 --> 00:13:33,578 ♪♪ 264 00:13:33,580 --> 00:13:37,348 If the planet stopped rotating, that organization would be gone. 265 00:13:37,350 --> 00:13:42,353 ♪♪ 266 00:13:42,355 --> 00:13:44,989 Narrator: Yet the genius of the voyager spacecraft 267 00:13:44,991 --> 00:13:46,825 Was that they were not just visiting jupiter 268 00:13:46,827 --> 00:13:48,726 In order to examine the planet. 269 00:13:48,728 --> 00:13:52,664 The four giant galilean moons were a key objective, 270 00:13:52,666 --> 00:13:56,167 And none more so than the mysterious moon io. 271 00:13:56,169 --> 00:14:01,806 ♪♪ 272 00:14:01,808 --> 00:14:03,308 Bagenal: As we were coming in, 273 00:14:03,310 --> 00:14:07,679 The ultraviolet instrument was saying, "whoa, this is bright. 274 00:14:07,681 --> 00:14:10,815 There's a lot of gas around this environment near io. 275 00:14:10,817 --> 00:14:13,551 You better be careful." 276 00:14:13,553 --> 00:14:19,757 Voyager flew by, and we saw it covered with volcanoes. 277 00:14:19,759 --> 00:14:21,292 Narrator: Scientists realized 278 00:14:21,294 --> 00:14:24,162 That io's volcanic gases could be contributing 279 00:14:24,164 --> 00:14:27,699 To the unprecedented radiation surrounding jupiter. 280 00:14:30,070 --> 00:14:33,705 Those gases were becoming trapped in the magnetic field, 281 00:14:33,707 --> 00:14:36,441 To make this doughnut of charged particles. 282 00:14:36,443 --> 00:14:39,444 They get accelerated to very high energies. 283 00:14:41,481 --> 00:14:44,816 Most of them go out to fill a big volume. 284 00:14:44,818 --> 00:14:46,451 Some of them go in. 285 00:14:46,453 --> 00:14:49,287 And as they go in, they go to even higher energies, 286 00:14:49,289 --> 00:14:53,157 And form this very tight environment close to jupiter -- 287 00:14:53,159 --> 00:14:55,894 This lethal radiation environment. 288 00:14:55,896 --> 00:14:58,463 That inner region is very analogous 289 00:14:58,465 --> 00:15:01,065 To the van allen belts of earth, 290 00:15:01,067 --> 00:15:06,504 But many times stronger, and more nasty. 291 00:15:06,506 --> 00:15:08,740 The background radiation here on earth 292 00:15:08,742 --> 00:15:11,276 That we're exposed to is about 1/3 of a rad. 293 00:15:11,278 --> 00:15:16,247 At jupiter, the radiation environment is 20 million rad. 294 00:15:18,351 --> 00:15:22,854 We did know io, europa, ganymede are in these orbital resonances. 295 00:15:22,856 --> 00:15:24,289 The orbits are elliptical. 296 00:15:24,291 --> 00:15:28,126 And so, when I was close to jupiter, it squeezes it. 297 00:15:28,128 --> 00:15:31,863 And when it's further away from jupiter, the squeeze is less. 298 00:15:31,865 --> 00:15:35,033 And so, you're literally looking at io going like this. 299 00:15:35,035 --> 00:15:38,736 That heat has got to go somewhere. 300 00:15:38,738 --> 00:15:42,273 There had been a paper published in science magazine 301 00:15:42,275 --> 00:15:45,677 That had come out the week before voyager got there, 302 00:15:45,679 --> 00:15:49,914 Predicting volcanoes on io because of this tidal flexing. 303 00:15:49,916 --> 00:15:54,752 Narrator: But io's volcanoes wouldn't be voyager's only lunar bombshell. 304 00:15:58,658 --> 00:16:00,792 You know, we knew there was something weird about europa. 305 00:16:00,794 --> 00:16:03,328 It was bright, and maybe it had these weird markings. 306 00:16:03,330 --> 00:16:05,930 But you couldn't really see them before. 307 00:16:08,735 --> 00:16:10,435 And then, all of a sudden, there it is. 308 00:16:10,437 --> 00:16:12,470 And as the first image is appearing on the screen, 309 00:16:12,472 --> 00:16:14,973 You know, europa has all these cracks in the ice, 310 00:16:14,975 --> 00:16:16,708 And these, like, lines going across. 311 00:16:16,710 --> 00:16:19,644 [ indistinct talking ] 312 00:16:19,646 --> 00:16:21,913 In that moment, it was just like, "whoa. 313 00:16:21,915 --> 00:16:23,247 What does that mean? 314 00:16:26,186 --> 00:16:28,353 Patel: As an airless body, we kind of expect things 315 00:16:28,355 --> 00:16:29,687 To be bombarded all the time, 316 00:16:29,689 --> 00:16:31,823 So you end up with a surface peppered with craters, 317 00:16:31,825 --> 00:16:32,857 Much like our moon. 318 00:16:32,859 --> 00:16:34,892 [ indistinct talking ] 319 00:16:34,894 --> 00:16:37,528 Turtle: Because the cratering rate throughout the solar system 320 00:16:37,530 --> 00:16:40,131 Is relatively well understood. 321 00:16:40,133 --> 00:16:43,534 The fact that europa has so few craters 322 00:16:43,536 --> 00:16:45,336 Is very consistent with it having 323 00:16:45,338 --> 00:16:47,305 A young surface, with a surface 324 00:16:47,307 --> 00:16:50,208 That has been geologically resurfaced. 325 00:16:53,713 --> 00:16:57,615 Bagenal: The voyager observations were so spectacular -- 326 00:16:57,617 --> 00:16:59,684 The dynamics of the atmosphere, 327 00:16:59,686 --> 00:17:02,620 The different kinds of moons, and what was going on. 328 00:17:02,622 --> 00:17:04,055 Everybody said, "we got to go back." 329 00:17:10,196 --> 00:17:13,998 Bagenal: The voyager observations were so spectacular, 330 00:17:14,000 --> 00:17:16,100 Everybody said, "we got to go back." 331 00:17:16,102 --> 00:17:18,369 But this time, we have to go back and stay. 332 00:17:18,371 --> 00:17:22,607 With voyager, we had a couple of very short, fleeting flybys. 333 00:17:22,609 --> 00:17:24,609 Like, you know, squeezing some pictures 334 00:17:24,611 --> 00:17:26,611 Out your car window as you drive by, 335 00:17:26,613 --> 00:17:28,279 As opposed to actually stopping, 336 00:17:28,281 --> 00:17:32,050 Getting out of the car, and exploring. 337 00:17:32,052 --> 00:17:35,119 Narrator: Before voyager had jupiter in its rearview mirror, 338 00:17:35,121 --> 00:17:37,021 Nasa had been building a spacecraft 339 00:17:37,023 --> 00:17:40,792 They intended to go into orbit around the giant planet. 340 00:17:40,794 --> 00:17:45,396 The mission was called "galileo." 341 00:17:45,398 --> 00:17:48,466 Maize: Galileo had a fitful start right from the very beginning 342 00:17:48,468 --> 00:17:51,202 About how exactly it was going to get to jupiter. 343 00:17:51,204 --> 00:17:54,772 Narrator: Galileo was scheduled to launch in January 1982 344 00:17:54,774 --> 00:17:58,242 On board the space shuttle. 345 00:17:58,244 --> 00:18:01,179 The launch date slipped to '84... 346 00:18:01,181 --> 00:18:03,381 Then '85... 347 00:18:03,383 --> 00:18:06,117 And then '86. 348 00:18:06,119 --> 00:18:07,652 And then, the whole shuttle program 349 00:18:07,654 --> 00:18:09,821 Suffered a terrible tragedy. 350 00:18:12,692 --> 00:18:15,593 The significance of that, of course, the loss of life, 351 00:18:15,595 --> 00:18:17,595 And the disruption of the whole program, 352 00:18:17,597 --> 00:18:20,698 But to us was that we didn't have a launch vehicle. 353 00:18:20,700 --> 00:18:22,934 And so, we packed up our spacecraft, 354 00:18:22,936 --> 00:18:24,635 And took it back to california, 355 00:18:24,637 --> 00:18:27,438 To try and figure out what to do. 356 00:18:27,440 --> 00:18:29,307 Narrator: Not only was the launch delayed, 357 00:18:29,309 --> 00:18:32,810 But after the challenger accident, nasa was rattled. 358 00:18:32,812 --> 00:18:35,680 The liquid hydrogen-fueled rocket booster 359 00:18:35,682 --> 00:18:38,316 That was originally intended to deliver galileo 360 00:18:38,318 --> 00:18:42,386 Directly to jupiter was now considered unsafe. 361 00:18:42,388 --> 00:18:44,422 Maize: It was no longer possible to take galileo 362 00:18:44,424 --> 00:18:46,157 Straight up to jupiter. 363 00:18:46,159 --> 00:18:47,892 And that's where the mission designers, here, 364 00:18:47,894 --> 00:18:49,060 Pulled a rabbit out of the hat, 365 00:18:49,062 --> 00:18:50,895 And found the so-called "veega" -- 366 00:18:50,897 --> 00:18:53,197 Venus-earth-earth gravity assist trajectory 367 00:18:53,199 --> 00:18:55,500 That took another five years to get there. 368 00:18:57,670 --> 00:18:59,604 Woman: We have a go [indistinct] 369 00:18:59,606 --> 00:19:05,910 6...5...4...3...2...1. 370 00:19:05,912 --> 00:19:08,379 We have ignition and liftoff of atlantis, 371 00:19:08,381 --> 00:19:11,716 And the galileo spacecraft bound for jupiter. 372 00:19:11,718 --> 00:19:17,088 ♪♪ 373 00:19:17,090 --> 00:19:22,460 ♪♪ 374 00:19:22,462 --> 00:19:25,763 Man: Galileo is on its way to another world. 375 00:19:25,765 --> 00:19:27,365 Fly safe. 376 00:19:27,367 --> 00:19:28,866 Maize: After the first earth flyby, 377 00:19:28,868 --> 00:19:32,136 We knew we would be far enough away from the sun 378 00:19:32,138 --> 00:19:36,874 That we could actually begin to use the high-bream antenna. 379 00:19:36,876 --> 00:19:37,975 It was like an umbrella. 380 00:19:37,977 --> 00:19:40,111 You imagine an umbrella being folded up. 381 00:19:40,113 --> 00:19:41,779 And when the time came, 382 00:19:41,781 --> 00:19:43,548 The spacecraft would fire a device, 383 00:19:43,550 --> 00:19:45,883 And the antenna could unfold. 384 00:19:45,885 --> 00:19:50,788 So, we activated the motor to free the antenna. 385 00:19:50,790 --> 00:19:51,956 And it stuck. 386 00:19:54,694 --> 00:19:56,928 Can you imagine -- [ imitates machinery whirring ] 387 00:19:56,930 --> 00:19:58,062 And it stalled, 388 00:19:58,064 --> 00:20:01,265 Only partially deploying some of the antenna. 389 00:20:01,267 --> 00:20:05,002 And the motor doesn't reverse. 390 00:20:05,004 --> 00:20:07,838 We could tell the antenna had deployed a little bit 391 00:20:07,840 --> 00:20:10,708 Because the spacecraft's spin wasn't quite the same, 392 00:20:10,710 --> 00:20:12,276 It's like if you took out one arm, and you're spinning, 393 00:20:12,278 --> 00:20:13,978 You start to do this a little bit. 394 00:20:13,980 --> 00:20:15,346 Well, the antenna was doing that little bit. 395 00:20:15,348 --> 00:20:16,647 So, we knew it opened some. 396 00:20:16,649 --> 00:20:18,216 Casani: So, why didn't it open? 397 00:20:18,218 --> 00:20:22,420 The antenna had remained stowed for so long, 398 00:20:22,422 --> 00:20:25,756 And the fact that it went into 2 vibration environments. 399 00:20:25,758 --> 00:20:29,360 Once, when we latched this spacecraft up in california -- 400 00:20:29,362 --> 00:20:32,997 Trucked it down to kennedy, trucked it back to pasadena. 401 00:20:32,999 --> 00:20:34,565 Said, "let's not mess with that antenna. 402 00:20:34,567 --> 00:20:35,733 It was all put together right. 403 00:20:35,735 --> 00:20:37,401 We'll just leave it the way it was." 404 00:20:37,403 --> 00:20:38,569 Back to the cape again. 405 00:20:38,571 --> 00:20:40,738 So, it made three trips across the cape, 406 00:20:40,740 --> 00:20:43,207 And the truck was just vibrating the whole time. 407 00:20:45,111 --> 00:20:46,410 Maize: And so, we did a lot of things. 408 00:20:46,412 --> 00:20:49,347 We worked on calibrating how far the antenna was open, 409 00:20:49,349 --> 00:20:51,282 Could we use it the way it was, 410 00:20:51,284 --> 00:20:53,484 And could we do the cold turns to free it up, 411 00:20:53,486 --> 00:20:54,952 And see if anything springs free? 412 00:20:54,954 --> 00:20:57,888 And we'd know, again, by seeing the spin rates change, 413 00:20:57,890 --> 00:20:59,257 If anything broke free. 414 00:20:59,259 --> 00:21:03,294 So, we spent a couple of years working on those things. 415 00:21:03,296 --> 00:21:08,332 Narrator: Jpl never got the high-gain antenna to open. 416 00:21:08,334 --> 00:21:09,834 Casani: Our capability at jupiter 417 00:21:09,836 --> 00:21:11,269 With an antenna that hadn't opened 418 00:21:11,271 --> 00:21:15,273 Was going to be dependent upon a single low-gain antenna. 419 00:21:15,275 --> 00:21:17,375 And that just meant we had to transmit 420 00:21:17,377 --> 00:21:20,077 A lot fewer pictures over the same time. 421 00:21:23,983 --> 00:21:26,817 Bagenal: The galileo spacecraft carried along with it 422 00:21:26,819 --> 00:21:30,021 A probe, that's sort of like this size. 423 00:21:30,023 --> 00:21:33,491 And it had a big heat shield to protect it around it. 424 00:21:33,493 --> 00:21:37,728 So, in July 1995, we launched that probe, 425 00:21:37,730 --> 00:21:39,864 And sent it in the direction of jupiter. 426 00:21:39,866 --> 00:21:42,199 Now, it didn't have engines, so we weren't guiding it, 427 00:21:42,201 --> 00:21:43,801 And saying, "go there." 428 00:21:43,803 --> 00:21:47,805 We just sort of sent it on a trajectory towards jupiter. 429 00:21:47,807 --> 00:21:53,444 Narrator: Five months later, on December 7th, 1995, 430 00:21:53,446 --> 00:21:58,149 The galileo probe arrived at jupiter. 431 00:21:58,151 --> 00:22:01,152 There were no cameras on board, 432 00:22:01,154 --> 00:22:04,989 Only sensors and a small probe that was going to have 433 00:22:04,991 --> 00:22:08,859 An extremely violent introduction to jupiter. 434 00:22:08,861 --> 00:22:14,432 Bagenal: It was coming in at something like 130,000 miles an hour. 435 00:22:14,434 --> 00:22:16,734 It was pulled in by the gravity of jupiter, 436 00:22:16,736 --> 00:22:19,737 And we had to slow it down. 437 00:22:19,739 --> 00:22:23,541 And so, this heat shield heated up to about three times 438 00:22:23,543 --> 00:22:25,710 The temperature of the surface of the sun. 439 00:22:29,015 --> 00:22:31,282 Narrator: During its maximum deceleration, 440 00:22:31,284 --> 00:22:35,586 The probe endured forces of 228 gs, 441 00:22:35,588 --> 00:22:39,724 And then, eventually, we kicked off the heat shield, 442 00:22:39,726 --> 00:22:42,727 Put out some parachutes. 443 00:22:42,729 --> 00:22:46,731 What we were expecting was three separate layers of clouds. 444 00:22:46,733 --> 00:22:51,669 ♪♪ 445 00:22:51,671 --> 00:22:52,770 And we went down. 446 00:22:52,772 --> 00:22:55,172 It was like, "where are the clouds?" 447 00:22:55,174 --> 00:22:58,008 Well, the hint came from the ground. 448 00:22:58,010 --> 00:23:00,845 Telescopes on earth were looking in the infrared, 449 00:23:00,847 --> 00:23:03,647 At jupiter, at the same time we sent the probe in. 450 00:23:03,649 --> 00:23:07,818 We realized that the probe went into a hotspot, 451 00:23:07,820 --> 00:23:10,921 Somewhere where there's very little water. 452 00:23:10,923 --> 00:23:14,325 And so, I think we realized that our whole idea of exploring 453 00:23:14,327 --> 00:23:16,360 These planets with single probes 454 00:23:16,362 --> 00:23:20,398 Is a little bit susceptible to going into the wrong place. 455 00:23:20,400 --> 00:23:25,236 Bagenal: By the time the probe had got down to about 160 kilometers, 456 00:23:25,238 --> 00:23:28,139 Something like 23 times atmospheric pressure, 457 00:23:28,141 --> 00:23:31,041 It was now starting to get really hot. 458 00:23:31,043 --> 00:23:33,377 And so, at that point, the electronics 459 00:23:33,379 --> 00:23:36,714 Is just not working anymore, and it stops communicating, 460 00:23:36,716 --> 00:23:40,618 And sending signals back to the earth. 461 00:23:40,620 --> 00:23:42,420 What happened to it after that? 462 00:23:42,422 --> 00:23:45,856 Well, it was so hot that it basically vaporized. 463 00:23:48,494 --> 00:23:50,995 But let's imagine what it would be like 464 00:23:50,997 --> 00:23:54,965 If you could be in a pressurized capsule as you get deeper down. 465 00:23:54,967 --> 00:23:57,635 It would get a little calmer, a little less turbulent. 466 00:23:57,637 --> 00:24:01,272 The pressure would get higher and higher. 467 00:24:01,274 --> 00:24:04,842 Bolton: It's so hot. Everything's vaporous. 468 00:24:04,844 --> 00:24:06,444 Eventually, you get down to material 469 00:24:06,446 --> 00:24:08,179 That are almost like rock clouds. 470 00:24:08,181 --> 00:24:10,514 And they're probably precipitating. 471 00:24:10,516 --> 00:24:14,752 Bagenal: Now, when you get down something like 10% of the radius, 472 00:24:14,754 --> 00:24:17,855 And the density is getting really high. 473 00:24:17,857 --> 00:24:21,926 And at that point, hydrogen changes its phase. 474 00:24:21,928 --> 00:24:24,195 It's no longer molecules -- 475 00:24:24,197 --> 00:24:27,097 Protons and electrons connected together -- 476 00:24:27,099 --> 00:24:30,835 But the protons and the electrons are moving separately. 477 00:24:30,837 --> 00:24:33,003 And it becomes metallic. 478 00:24:33,005 --> 00:24:35,873 That is, it becomes electrically conducting. 479 00:24:35,875 --> 00:24:38,809 And in this region, you can generate a magnetic field, 480 00:24:38,811 --> 00:24:40,611 What's called a "dynamo." 481 00:24:40,613 --> 00:24:43,914 The fluids convert some of their motional energy 482 00:24:43,916 --> 00:24:47,084 Into magnetic field energy, into current. 483 00:24:49,755 --> 00:24:52,423 On earth, the dynamo is very far from us, 484 00:24:52,425 --> 00:24:55,192 Earth's core is halfway through the planet, 485 00:24:55,194 --> 00:24:58,362 But on jupiter, you don't even go 10% of the way in, 486 00:24:58,364 --> 00:25:01,799 And you've got this 60,000 kilometer radius ball 487 00:25:01,801 --> 00:25:05,569 Of molten metallic material. 488 00:25:08,841 --> 00:25:10,941 And maybe that means it's not amazing 489 00:25:10,943 --> 00:25:14,178 That you generate a huge magnetic field. 490 00:25:14,180 --> 00:25:17,414 Narrator: Now that the galileo probe had succeeded with its mission, 491 00:25:17,416 --> 00:25:20,150 And ultimately vaporized inside jupiter, 492 00:25:20,152 --> 00:25:22,720 The mothership needed to avoid a similar fate, 493 00:25:22,722 --> 00:25:25,556 And insert itself safely into orbit. 494 00:25:25,558 --> 00:25:27,892 Bolton: In just that first pass, when we were getting into orbit, 495 00:25:27,894 --> 00:25:30,594 Galileo received half of its radiation dose -- 496 00:25:30,596 --> 00:25:33,664 Like 150 kilorads in one shot. 497 00:25:33,666 --> 00:25:37,001 Then, it went out further, and kind of licked its wounds. 498 00:25:37,003 --> 00:25:40,137 Bagenal: Because of galileo having this broken antenna, 499 00:25:40,139 --> 00:25:43,641 It meant that we tended to focus further out first. 500 00:25:43,643 --> 00:25:47,378 And the first really exciting thing we found was 501 00:25:47,380 --> 00:25:51,115 Ganymede has its own magnetic field. 502 00:25:51,117 --> 00:25:53,784 Narrator: The seventh moon out from the surface of jupiter, 503 00:25:53,786 --> 00:25:57,221 Ganymede is a moon the size of a planet. 504 00:25:57,223 --> 00:25:58,956 Larger than mercury, 505 00:25:58,958 --> 00:26:02,026 It is the biggest moon in our solar system. 506 00:26:02,028 --> 00:26:04,662 The fact that ganymede has a magnetic field 507 00:26:04,664 --> 00:26:07,164 Means that it might have some ability to protect itself 508 00:26:07,166 --> 00:26:09,900 From the harsh radiation of jupiter -- 509 00:26:09,902 --> 00:26:14,138 A key attribute for a habitat where life might be found. 510 00:26:14,140 --> 00:26:17,107 So, now it starts to open up how we think about even 511 00:26:17,109 --> 00:26:20,177 "what's a planetary body," right? 512 00:26:20,179 --> 00:26:23,380 These moons, how different are they from other planets? 513 00:26:23,382 --> 00:26:25,482 They can have their own magnetic fields. 514 00:26:30,556 --> 00:26:32,856 Narrator: But now, the galileo spacecraft, 515 00:26:32,858 --> 00:26:34,391 Despite its troubles, 516 00:26:34,393 --> 00:26:37,261 Was about to make arguably the most important discovery 517 00:26:37,263 --> 00:26:40,164 In the history of space flight, 518 00:26:40,166 --> 00:26:42,933 At the mysterious moon that voyager had visited 519 00:26:42,935 --> 00:26:46,503 17 years before -- europa. 520 00:26:51,143 --> 00:26:53,877 Woman: We have ignition and liftoff of atlantis, 521 00:26:53,879 --> 00:26:57,848 And the galileo spacecraft bound for jupiter. 522 00:26:57,850 --> 00:27:01,352 Narrator: When the galileo spacecraft launched in 1989, 523 00:27:01,354 --> 00:27:03,988 The mission promised to uncover jupiter's secrets. 524 00:27:03,990 --> 00:27:07,024 But what it revealed about the planet's moon, europa, 525 00:27:07,026 --> 00:27:11,095 Surpassed even scientist's wildest expectations. 526 00:27:11,097 --> 00:27:14,632 Bagenal: What we measured as we flew by was something quite remarkable. 527 00:27:14,634 --> 00:27:17,635 There were electrical currents that were flowing 528 00:27:17,637 --> 00:27:23,207 Inside the moon that perturbed the magnetic field. 529 00:27:23,209 --> 00:27:27,778 And we concluded that europa has to have a liquid ocean 530 00:27:27,780 --> 00:27:29,013 Underneath that ice. 531 00:27:29,015 --> 00:27:35,119 ♪♪ 532 00:27:35,121 --> 00:27:39,423 And the reason is, ice is not very electrically conducting. 533 00:27:39,425 --> 00:27:43,560 You need it to be liquefied as water, in a big ocean, 534 00:27:43,562 --> 00:27:45,663 To carry those electrical currents. 535 00:27:47,299 --> 00:27:49,633 Probably has to have salt in it 536 00:27:49,635 --> 00:27:50,868 To be electrically conducting, 537 00:27:50,870 --> 00:27:53,103 The way that the earth's salty ocean 538 00:27:53,105 --> 00:27:55,105 Is electrically conducting. 539 00:27:55,107 --> 00:27:58,442 James: And the reason why we hardly see any craters 540 00:27:58,444 --> 00:28:00,377 On the surface of europa 541 00:28:00,379 --> 00:28:03,147 Is because that ocean has squirted out, 542 00:28:03,149 --> 00:28:05,683 And has filled them in over time. 543 00:28:05,685 --> 00:28:10,621 Like io, europa, which is also in an elliptical orbit, 544 00:28:10,623 --> 00:28:14,091 And gets squeezed and relaxed every two or so days 545 00:28:14,093 --> 00:28:18,128 As it goes around the planet, is dissipating that heat 546 00:28:18,130 --> 00:28:20,931 By melting that ice shell. 547 00:28:20,933 --> 00:28:24,668 We believe the ocean can be as thick as a hundred miles, 548 00:28:24,670 --> 00:28:26,236 And maybe even thicker. 549 00:28:26,238 --> 00:28:30,007 And at the rocky surface at the bottom of the ocean, 550 00:28:30,009 --> 00:28:32,843 I know exactly what it looks like -- 551 00:28:32,845 --> 00:28:35,713 Hydrothermal vents. 552 00:28:35,715 --> 00:28:39,416 Narrator: Such vents are also found here on earth. 553 00:28:39,418 --> 00:28:42,720 And those hydrothermal vents span fields. 554 00:28:42,722 --> 00:28:44,455 So, it's not just a single chimney, 555 00:28:44,457 --> 00:28:46,590 But there's a field of chimneys, if you like. 556 00:28:46,592 --> 00:28:48,559 And those fields, we think, on the early earth, 557 00:28:48,561 --> 00:28:50,194 And potentially on some moons, 558 00:28:50,196 --> 00:28:52,196 Could spread across an entire sea floor. 559 00:28:52,198 --> 00:28:54,397 You have this kind of porous labyrinth 560 00:28:54,399 --> 00:28:58,335 Of interconnected pores, through hydrogen from the vents 561 00:28:58,337 --> 00:29:02,439 Mixing with co2 from the oceans, making organic molecules. 562 00:29:02,441 --> 00:29:05,642 And here, you have a setting which looks an awful lot 563 00:29:05,644 --> 00:29:09,179 Like the way that modern cells work. 564 00:29:09,181 --> 00:29:10,681 And this kind of chemistry 565 00:29:10,683 --> 00:29:13,984 Was almost certainly behind the origin of life on earth. 566 00:29:20,159 --> 00:29:23,527 When you look at europa, and you look at the cracks, 567 00:29:23,529 --> 00:29:25,562 There is this brown, gunky stuff 568 00:29:25,564 --> 00:29:29,500 That seems to be coming from the interior. 569 00:29:29,502 --> 00:29:33,871 But also, could it be that there's a source of chemistry 570 00:29:33,873 --> 00:29:36,306 Coming from io, and io's volcanoes, 571 00:29:36,308 --> 00:29:38,976 Impacting the surface of europa, 572 00:29:38,978 --> 00:29:40,444 Bringing sulfur -- 573 00:29:40,446 --> 00:29:44,081 And perhaps more importantly, oxygen -- into europa, 574 00:29:44,083 --> 00:29:47,818 And that material then gets carried down into the ocean, 575 00:29:47,820 --> 00:29:51,054 Oxidizing the environment of the ocean, 576 00:29:51,056 --> 00:29:55,125 And maybe enhancing the life that may -- maybe is there? 577 00:29:55,127 --> 00:29:58,061 Maybe not. We don't know. 578 00:29:58,063 --> 00:30:01,665 Grinspoon: I think that europa is a place where, 579 00:30:01,667 --> 00:30:03,433 Given what we think we know about life, 580 00:30:03,435 --> 00:30:04,701 There ought to be life. 581 00:30:04,703 --> 00:30:07,437 But by then, we've kind of done 582 00:30:07,439 --> 00:30:09,540 What we were gonna do with galileo. 583 00:30:09,542 --> 00:30:11,275 Maize: And the radiation of jupiter is very, 584 00:30:11,277 --> 00:30:13,043 Very hard on electronics. 585 00:30:13,045 --> 00:30:14,344 So, it rips up the spacecraft. 586 00:30:14,346 --> 00:30:16,646 It goes into saving, stops, all the sequences, 587 00:30:16,648 --> 00:30:18,882 And you have to restart things. 588 00:30:18,884 --> 00:30:22,553 Narrator: After having its mission extended three times, 589 00:30:22,555 --> 00:30:27,457 It was eventually decided in 2003 to dispose of the aging, 590 00:30:27,459 --> 00:30:30,427 Radiation-damaged spacecraft -- 591 00:30:30,429 --> 00:30:33,297 By flying it into the clouds of jupiter. 592 00:30:36,302 --> 00:30:38,669 Bolton: We learned so much from galileo. 593 00:30:38,671 --> 00:30:41,905 In fact, it was really the results of galileo 594 00:30:41,907 --> 00:30:43,540 That led us to juno. 595 00:30:43,542 --> 00:30:48,645 Man: Liftoff od the atlas five, with juno, on a trip to jupiter. 596 00:30:48,647 --> 00:30:51,181 Bagenal: The big question of the galileo was, 597 00:30:51,183 --> 00:30:54,318 Did that probe just go into somewhere weird, 598 00:30:54,320 --> 00:30:56,987 Or was the lack of water 599 00:30:56,989 --> 00:31:00,157 Symptomatic of the entire planet? 600 00:31:00,159 --> 00:31:02,459 Now, this is extremely important. 601 00:31:02,461 --> 00:31:05,162 In 30 minutes that it took the probe to go into jupiter, 602 00:31:05,164 --> 00:31:06,730 And get this data, 603 00:31:06,732 --> 00:31:10,133 Every theory of solar system formation was proven wrong. 604 00:31:10,135 --> 00:31:12,870 Bagenal: Because remember, we think the gas giants formed 605 00:31:12,872 --> 00:31:17,574 By having giant snowballs, say, 30 times the mass of the earth, 606 00:31:17,576 --> 00:31:21,245 That pull in the hydrogen to make the gas giants. 607 00:31:21,247 --> 00:31:24,248 So, at the core, we think there was ice. 608 00:31:24,250 --> 00:31:27,551 And yet, when we went in with that probe, 609 00:31:27,553 --> 00:31:29,720 We didn't see any -- or very little. 610 00:31:29,722 --> 00:31:31,088 So, what's going on? 611 00:31:31,090 --> 00:31:34,157 So, when juno came along, one of its primary objectives 612 00:31:34,159 --> 00:31:39,096 Was to go in, and see how much water and oxygen is in jupiter. 613 00:31:39,098 --> 00:31:41,465 We have to go back, and find out. 614 00:31:41,467 --> 00:31:43,600 And we could send in 100 probes, 615 00:31:43,602 --> 00:31:46,770 But, you know, that's gonna be expensive and difficult. 616 00:31:46,772 --> 00:31:48,705 And we thought of a clever way of doing it. 617 00:31:53,445 --> 00:31:56,613 Bolton: So, when juno came along, one of its primary objectives 618 00:31:56,615 --> 00:32:01,251 Was to go in, and see how much water and oxygen is in jupiter. 619 00:32:03,422 --> 00:32:06,590 Juno was designed in order to make measurements 620 00:32:06,592 --> 00:32:08,325 Almost over the whole planet, 621 00:32:08,327 --> 00:32:11,862 And look at the water, rather than in one spot. 622 00:32:11,864 --> 00:32:15,732 And to go much deeper remotely, not with a probe. 623 00:32:18,003 --> 00:32:22,472 The brilliant idea was to use microwaves. 624 00:32:22,474 --> 00:32:27,711 Everyone knows that microwaves are absorbed by water. 625 00:32:27,713 --> 00:32:31,281 So, what we want to do is fly over jupiter, 626 00:32:31,283 --> 00:32:34,518 And map out the distribution of water 627 00:32:34,520 --> 00:32:37,354 From the absorption of those microwaves. 628 00:32:37,356 --> 00:32:40,190 But to find out what it's like deep inside, 629 00:32:40,192 --> 00:32:43,327 We have to measure the distribution of mass inside 630 00:32:43,329 --> 00:32:47,630 That changes the gravity field in some subtle ways. 631 00:32:47,632 --> 00:32:50,133 Bolton: And to do that, we had to go into a polar orbit. 632 00:32:50,135 --> 00:32:52,936 And we also had to get really close. 633 00:32:55,007 --> 00:32:57,808 Now, remember, we've got a problem with jupiter. 634 00:32:57,810 --> 00:33:00,544 Jupiter has these radiation belts around it. 635 00:33:00,546 --> 00:33:03,180 You don't really want to take your sensitive electronics 636 00:33:03,182 --> 00:33:05,549 Of your spacecraft through that environment -- 637 00:33:05,551 --> 00:33:08,418 At least not for long. 638 00:33:08,420 --> 00:33:11,688 Bolton: We had to somehow get beneath the radiation belt 639 00:33:11,690 --> 00:33:13,724 If we can just thread that needle... 640 00:33:16,929 --> 00:33:19,396 I was just praying with my eyes closed, 641 00:33:19,398 --> 00:33:21,131 You know, that this was gonna work. 642 00:33:22,935 --> 00:33:26,803 We were getting a few thousand miles above the cloud tops 643 00:33:26,805 --> 00:33:29,339 When we were doing this maneuver. 644 00:33:29,341 --> 00:33:31,174 Nothing had ever been that close. 645 00:33:33,512 --> 00:33:35,879 Bagenal: Fly the engines. 646 00:33:35,881 --> 00:33:37,447 Woman: Good now? 647 00:33:37,449 --> 00:33:39,416 Yeah, we see that the engine has started. 648 00:33:41,253 --> 00:33:43,487 35 minutes, they're firing away, 649 00:33:43,489 --> 00:33:45,856 Slowing down the spacecraft, 650 00:33:45,858 --> 00:33:49,426 So it gets caught in jupiter's gravity. 651 00:33:49,428 --> 00:33:51,762 Woman: Juno, welcome to jupiter. 652 00:33:51,764 --> 00:33:53,964 [ cheering ] 653 00:33:53,966 --> 00:33:55,665 Nasa did it again. 654 00:33:57,636 --> 00:34:03,774 ♪♪ 655 00:34:03,776 --> 00:34:06,610 Bolton: And you know, the thing that was also sobering was, 656 00:34:06,612 --> 00:34:07,878 We were coming back. 657 00:34:07,880 --> 00:34:09,312 This was our game plan. 658 00:34:09,314 --> 00:34:10,814 Every orbit we were gonna have to go 659 00:34:10,816 --> 00:34:13,483 Run through that fire with our bare feet. 660 00:34:13,485 --> 00:34:17,254 Our view of jupiter before juno was from the equator. 661 00:34:17,256 --> 00:34:21,625 So, then, when juno flies over the poles, and is looking down, 662 00:34:21,627 --> 00:34:24,027 And there we see these vortices, 663 00:34:24,029 --> 00:34:27,731 All this structure, is just extraordinary. 664 00:34:31,070 --> 00:34:33,236 Little did we know that the poles of jupiter, 665 00:34:33,238 --> 00:34:36,940 We're gonna become this huge science discovery by itself -- 666 00:34:36,942 --> 00:34:38,508 Giant polar cyclones. 667 00:34:38,510 --> 00:34:40,577 Nobody anticipated that. 668 00:34:42,748 --> 00:34:44,214 When we fly in close, 669 00:34:44,216 --> 00:34:47,217 Measuring the perturbations in juno's motion, 670 00:34:47,219 --> 00:34:51,321 We're beginning to get a sense of what it's like inside. 671 00:34:51,323 --> 00:34:53,990 And what we're finding is that it's not like 672 00:34:53,992 --> 00:34:56,126 The textbook picture, where you have 673 00:34:56,128 --> 00:34:59,096 A metal rock core inside, 674 00:34:59,098 --> 00:35:03,366 And then a layer of hydrogen, and then a layer of gas above. 675 00:35:03,368 --> 00:35:05,669 It's much fuzzier, much more mixed up. 676 00:35:05,671 --> 00:35:08,038 And so, in fact, that core is spread out 677 00:35:08,040 --> 00:35:09,940 To about 40% of the radius. 678 00:35:09,942 --> 00:35:14,177 So, it's mixed in with the metallic hydrogen. 679 00:35:14,179 --> 00:35:17,080 You're beginning to see that the convection system 680 00:35:17,082 --> 00:35:18,248 We see on the outside 681 00:35:18,250 --> 00:35:20,083 Extend a long way in. 682 00:35:20,085 --> 00:35:21,585 They're much, much deeper. 683 00:35:26,825 --> 00:35:30,827 Arnou: But what juno has not yet been able to explain 684 00:35:30,829 --> 00:35:32,529 Is what drives the jets. 685 00:35:32,531 --> 00:35:37,067 It might be that turbulence at the surface drives these jets, 686 00:35:37,069 --> 00:35:41,404 And then the jets burrow down into the depths. 687 00:35:41,406 --> 00:35:43,106 But with jupiter, so much heat 688 00:35:43,108 --> 00:35:45,075 Is coming out of the interior of the planet 689 00:35:45,077 --> 00:35:48,311 That maybe the jets are being driven by deep motions, 690 00:35:48,313 --> 00:35:49,946 And it's their surface expression 691 00:35:49,948 --> 00:35:52,516 That we're seeing at the top. 692 00:35:52,518 --> 00:35:54,851 Bolton: There's probably something deep down 693 00:35:54,853 --> 00:35:59,055 That is driving a lot of motion inside of jupiter. 694 00:35:59,057 --> 00:36:02,325 Bagenal: And so, we're beginning to think about that region 695 00:36:02,327 --> 00:36:04,494 Where hydrogen becomes metallic, 696 00:36:04,496 --> 00:36:07,531 That generates this strong magnetic field. 697 00:36:07,533 --> 00:36:10,834 Bolton: The magnetic field is probably moving things around, 698 00:36:10,836 --> 00:36:14,137 Driving convection, and eddies, and all kinds of motion. 699 00:36:14,139 --> 00:36:16,606 And so, somewhere, there's a balancing act. 700 00:36:16,608 --> 00:36:19,509 The stuff that's coming in from the top meets the stuff 701 00:36:19,511 --> 00:36:21,178 That's coming up from the bottom, 702 00:36:21,180 --> 00:36:22,913 And all hell breaks loose. 703 00:36:27,986 --> 00:36:29,553 Arnou: With jupiter, so much heat 704 00:36:29,555 --> 00:36:31,388 Is coming out of the interior of the planet 705 00:36:31,390 --> 00:36:34,491 That maybe the jets are being driven by deep motions, 706 00:36:34,493 --> 00:36:36,126 And it's their surface expression 707 00:36:36,128 --> 00:36:37,694 That we're seeing at the top. 708 00:36:39,698 --> 00:36:40,864 What's the right answer? 709 00:36:40,866 --> 00:36:44,501 We do not yet know. Open question. 710 00:36:44,503 --> 00:36:48,338 One of the great questions, for me, as a scientist, 711 00:36:48,340 --> 00:36:52,142 Looking at jupiter, and studying jupiter. 712 00:36:52,144 --> 00:36:54,844 Bolton: Nobody really knows for sure what makes the colors 713 00:36:54,846 --> 00:36:56,846 In jupiter's zones and belts. 714 00:36:56,848 --> 00:36:58,582 We see all these oranges, and reds, 715 00:36:58,584 --> 00:37:00,517 And beautiful yellows. Right? And browns. 716 00:37:00,519 --> 00:37:03,587 And io is spewing out tons of sulfur, 717 00:37:03,589 --> 00:37:07,390 Among other things, because it's volcanic. 718 00:37:07,392 --> 00:37:08,725 So, in many ways, 719 00:37:08,727 --> 00:37:11,528 The combination of io and its volcanoes 720 00:37:11,530 --> 00:37:14,064 With jupiter's strong magnetic field 721 00:37:14,066 --> 00:37:19,903 Is really at the core of an engine, or a generator. 722 00:37:19,905 --> 00:37:22,305 When we laid out the objectives of juno, 723 00:37:22,307 --> 00:37:24,374 It was to go sort of figure out the puzzles 724 00:37:24,376 --> 00:37:26,543 Of what it was made out of, and how it formed. 725 00:37:26,545 --> 00:37:29,112 Nobody really conceived of the idea that we'd go there, 726 00:37:29,114 --> 00:37:30,480 And the entire structure 727 00:37:30,482 --> 00:37:32,015 Was gonna be different than we thought. 728 00:37:34,953 --> 00:37:38,288 It may be that we've been a bit naive, 729 00:37:38,290 --> 00:37:40,957 That if jupiter could throw us this many curveballs, 730 00:37:40,959 --> 00:37:45,462 That our ideas of how stars work could be kind of wrong, too. 731 00:37:45,464 --> 00:37:46,863 I mean, there's even more energy. 732 00:37:46,865 --> 00:37:48,465 And they're even more massive. 733 00:37:50,469 --> 00:37:53,270 Astronomers have looked out, and seen many stars, right? 734 00:37:53,272 --> 00:37:54,838 Billions and billions. 735 00:37:54,840 --> 00:37:57,474 Many of those are binary systems -- 736 00:37:57,476 --> 00:37:59,776 Two stars going around each other. 737 00:37:59,778 --> 00:38:02,712 Sometimes, there's a big star and a little star -- 738 00:38:02,714 --> 00:38:05,749 Maybe a star that has only a tiny bit of fusion inside, 739 00:38:05,751 --> 00:38:06,883 Like a brown dwarf. 740 00:38:06,885 --> 00:38:09,219 In our case, and many others we've seen, 741 00:38:09,221 --> 00:38:12,222 Where we have a star and a planetary system, 742 00:38:12,224 --> 00:38:15,659 The biggest planet does not have enough mass 743 00:38:15,661 --> 00:38:18,228 To have a fusion reaction inside. 744 00:38:18,230 --> 00:38:20,030 So, let's think of our solar system, 745 00:38:20,032 --> 00:38:22,532 Where we have the sun, and we have jupiter. 746 00:38:22,534 --> 00:38:27,404 And jupiter is 1000th the volume, 747 00:38:27,406 --> 00:38:30,273 And 1000th the mass of the sun. 748 00:38:30,275 --> 00:38:33,877 And so, it's too small to have fusion inside. 749 00:38:33,879 --> 00:38:35,945 It's a failed star. 750 00:38:35,947 --> 00:38:38,515 But it's a very successful planet. 751 00:38:38,517 --> 00:38:45,755 ♪♪ 752 00:38:45,757 --> 00:38:49,092 Narrator: Juno continues to explore jupiter, 753 00:38:49,094 --> 00:38:51,528 Diving beneath the lethal radiation belts 754 00:38:51,530 --> 00:38:53,930 On every daring orbit. 755 00:38:53,932 --> 00:38:56,099 And each time, we learn a little more 756 00:38:56,101 --> 00:38:58,902 About the greatest planet in the solar system. 757 00:39:01,106 --> 00:39:06,843 But we have unfinished business with some of its moons. 758 00:39:06,845 --> 00:39:09,979 Juice is the next major exploration mission 759 00:39:09,981 --> 00:39:12,582 For the european space agency -- 760 00:39:12,584 --> 00:39:16,019 Jupiter icy moons explorer. 761 00:39:16,021 --> 00:39:18,121 Its sole purpose is to go to jupiter, 762 00:39:18,123 --> 00:39:19,889 And explore the icy moons. 763 00:39:21,960 --> 00:39:24,094 The main aim is really to try and understand 764 00:39:24,096 --> 00:39:26,162 What they look like below the surface. 765 00:39:26,164 --> 00:39:28,231 How thick is the ice layer? 766 00:39:28,233 --> 00:39:30,367 How deep is subsurface ocean? 767 00:39:30,369 --> 00:39:32,569 For places like europa, ganymede, 768 00:39:32,571 --> 00:39:35,772 Getting below the ice layer is the holy grail. 769 00:39:35,774 --> 00:39:38,208 Getting into that subsurface ocean 770 00:39:38,210 --> 00:39:39,409 That is a whole new frontier. 771 00:39:39,411 --> 00:39:41,077 And that will be a fascinating thing, 772 00:39:41,079 --> 00:39:43,780 If we can ever achieve that. 773 00:39:43,782 --> 00:39:46,616 Juice doesn't launch till 2022. 774 00:39:46,618 --> 00:39:50,720 It's not gonna get there until 2030. 775 00:39:50,722 --> 00:39:52,822 Some of the people already working on it now 776 00:39:52,824 --> 00:39:54,324 Will have retired. 777 00:39:54,326 --> 00:39:56,092 Some will probably have passed away. 778 00:39:56,094 --> 00:39:57,560 What I love about it is that there's 779 00:39:57,562 --> 00:39:59,796 This generational feeling to it. 780 00:39:59,798 --> 00:40:01,798 By the time we get the data, 781 00:40:01,800 --> 00:40:05,234 There will be another generation of scientists looking at it. 782 00:40:05,236 --> 00:40:08,371 Klesh: Nasa has been funding a mission called "europa clipper," 783 00:40:08,373 --> 00:40:11,541 Which will take a number of flybys of europa 784 00:40:11,543 --> 00:40:13,676 To try and get a deeper investigation 785 00:40:13,678 --> 00:40:15,345 Of what might be happening on the surface -- 786 00:40:15,347 --> 00:40:17,514 Even a basic understanding of some of the chemistry 787 00:40:17,516 --> 00:40:19,382 That might be there, in preparation 788 00:40:19,384 --> 00:40:23,553 For investigations yet to come, getting down to the oceans. 789 00:40:23,555 --> 00:40:24,754 Well, the first challenge you have is actually 790 00:40:24,756 --> 00:40:27,090 Getting down through the ice. 791 00:40:27,092 --> 00:40:28,958 And while people have talked about drills, 792 00:40:28,960 --> 00:40:30,226 And other such things, 793 00:40:30,228 --> 00:40:32,228 We want to reduce this 20 kilometers of ice 794 00:40:32,230 --> 00:40:33,696 As much as possible. 795 00:40:33,698 --> 00:40:35,965 And so, we've built submersibles 796 00:40:35,967 --> 00:40:39,502 That can actually navigate through tunnels and canyons, 797 00:40:39,504 --> 00:40:41,438 To be able to try and make their way down through, 798 00:40:41,440 --> 00:40:42,772 Perhaps, theses open crevices 799 00:40:42,774 --> 00:40:44,707 As close to the water as possible. 800 00:40:44,709 --> 00:40:46,910 Now, if we can get into the water itself, 801 00:40:46,912 --> 00:40:48,278 We've built a buoyant rover 802 00:40:48,280 --> 00:40:51,080 That goes underneath the ice, and floats. 803 00:40:51,082 --> 00:40:53,016 So, drives on the underside of the ice 804 00:40:53,018 --> 00:40:55,585 Exactly at that ice-water boundary on there. 805 00:40:55,587 --> 00:40:58,421 And by turning a camera to look up at the microbes 806 00:40:58,423 --> 00:41:01,057 That we might find there on the underside of the ice. 807 00:41:01,059 --> 00:41:03,693 And then, we've been working on deep-ocean vessels, 808 00:41:03,695 --> 00:41:07,030 Where we hope to go down to the bottom of the ocean on europa, 809 00:41:07,032 --> 00:41:10,033 And then bring back samples to us of what might be 810 00:41:10,035 --> 00:41:12,035 Down at the bottom of the ocean. 811 00:41:12,037 --> 00:41:13,036 In the mid 2020s, 812 00:41:13,038 --> 00:41:15,205 We hope to launch europa clipper. 813 00:41:15,207 --> 00:41:17,140 Then, after a six to seven year voyage, 814 00:41:17,142 --> 00:41:19,709 Will reach jupiter itself. 815 00:41:19,711 --> 00:41:22,745 There is an immense opportunity for us 816 00:41:22,747 --> 00:41:25,915 To find the first signs of life beyond our world 817 00:41:25,917 --> 00:41:30,220 In these warm, watery, rich environments 818 00:41:30,222 --> 00:41:34,757 That we are just beginning to see that we can even access. 819 00:41:34,759 --> 00:41:35,992 And the rovers that we're developing, 820 00:41:35,994 --> 00:41:37,660 And testing here on earth, 821 00:41:37,662 --> 00:41:40,129 Are only the ancestors -- 822 00:41:40,131 --> 00:41:45,001 The far ancestors of what we might eventually send there. 823 00:41:45,003 --> 00:41:47,637 Narrator: So, perhaps one day, we will discover life 824 00:41:47,639 --> 00:41:52,308 Residing under the ice -- a precious habitat thriving 825 00:41:52,310 --> 00:41:55,411 Despite the brutal radioactive environment 826 00:41:55,413 --> 00:42:00,016 In the shadow of the mightiest planet in our solar system -- 827 00:42:00,018 --> 00:42:01,184 Jupiter.