1 00:00:00,000 --> 00:00:01,850 (tense music) 2 00:00:01,850 --> 00:00:05,393 Jupiter was cool because it's the biggest planet. 3 00:00:06,570 --> 00:00:07,410 It's spinal tap. 4 00:00:07,410 --> 00:00:10,060 Everything's turned up a little bit closer to 11. 5 00:00:10,060 --> 00:00:12,850 Jupiter is enormous. 6 00:00:12,850 --> 00:00:14,837 And everybody loves 11. 7 00:00:14,837 --> 00:00:17,640 (dramatic music) 8 00:00:17,640 --> 00:00:20,800 The great red spot, the drama of the poles, 9 00:00:20,800 --> 00:00:22,500 and all the vortices going around. 10 00:00:23,980 --> 00:00:27,370 It's got these fantastic cloud layers spinning around. 11 00:00:27,370 --> 00:00:30,500 These storms raging bigger than the Earth itself. 12 00:00:30,500 --> 00:00:31,470 And then the moons! 13 00:00:31,470 --> 00:00:33,950 It's like a little solar system in itself. 14 00:00:33,950 --> 00:00:36,330 Instead of a starred center with planets going around it. 15 00:00:36,330 --> 00:00:38,770 You've got Jupiter with moons going around it. 16 00:00:38,770 --> 00:00:41,140 79 moons. 17 00:00:41,140 --> 00:00:42,690 Four big ones. 18 00:00:42,690 --> 00:00:47,690 Io, Europa, Ganymede, and Callisto and they are huge! 19 00:00:48,220 --> 00:00:52,543 Each one their own world of ice, or rock, or volcano. 20 00:00:53,380 --> 00:00:56,310 It's a very violent, dangerous, 21 00:00:56,310 --> 00:00:58,673 deadly place in the solar system. 22 00:00:58,673 --> 00:01:00,290 (dramatic music) 23 00:01:00,290 --> 00:01:02,000 You send a spacecraft to Jupiter, 24 00:01:02,000 --> 00:01:03,750 you're gonna get fried really quick. 25 00:01:03,750 --> 00:01:04,658 (machine whirring) 26 00:01:04,658 --> 00:01:07,258 Can we send a spacecraft through that environment? 27 00:01:08,250 --> 00:01:09,780 The Greeks weren't wrong to make 28 00:01:09,780 --> 00:01:11,581 that thing the king of the gods. 29 00:01:11,581 --> 00:01:14,331 (dramatic music) 30 00:01:21,697 --> 00:01:24,280 (gentle music) 31 00:01:28,620 --> 00:01:30,740 Juno was gonna be the first spacecraft 32 00:01:30,740 --> 00:01:32,810 to fly over the poles of Jupiter, 33 00:01:32,810 --> 00:01:36,150 and it was due to arrive on the 4th of July. 34 00:01:36,150 --> 00:01:37,820 (dramatic music) 35 00:01:37,820 --> 00:01:39,510 That day I had my whole family. 36 00:01:39,510 --> 00:01:41,023 We were going into JPL. 37 00:01:41,950 --> 00:01:45,037 I remember turning to my kids in the backseat and said, 38 00:01:45,037 --> 00:01:47,457 "It might not work something bad could happen. 39 00:01:47,457 --> 00:01:49,997 "NASA and the country and the world 40 00:01:49,997 --> 00:01:51,867 "are taking a big risk here." 41 00:01:54,860 --> 00:01:57,170 We had no idea what this polar environment was like. 42 00:01:57,170 --> 00:01:59,670 We had some sense of the radiation belt. 43 00:01:59,670 --> 00:02:01,950 We knew they are nasty, 44 00:02:01,950 --> 00:02:04,089 really, really nasty. 45 00:02:04,089 --> 00:02:06,839 (dramatic music) 46 00:02:07,710 --> 00:02:09,090 Juno is an armored tank, 47 00:02:09,090 --> 00:02:11,403 but it's nothing compared to Jupiter. 48 00:02:12,390 --> 00:02:14,480 So we want to be really careful. 49 00:02:14,480 --> 00:02:16,233 Go through quickly and get out. 50 00:02:17,140 --> 00:02:20,670 And so, Juno is moving really fast. 51 00:02:20,670 --> 00:02:25,670 It was coming in at about 150,000 miles an hour, 52 00:02:26,380 --> 00:02:27,980 which is like going around the Earth 53 00:02:27,980 --> 00:02:30,263 five times in two hours. 54 00:02:31,350 --> 00:02:33,810 Not because we had this incredible prolusion system, 55 00:02:33,810 --> 00:02:37,271 but because Jupiter's gravity was sucking us in. 56 00:02:37,271 --> 00:02:39,430 (dramatic music) 57 00:02:39,430 --> 00:02:43,270 The engineers hoped that it wasn't gonna get us completely. 58 00:02:43,270 --> 00:02:45,456 We were gonna just go really close to it. 59 00:02:45,456 --> 00:02:48,206 (dramatic music) 60 00:02:50,350 --> 00:02:52,353 If it doesn't work, it's over. 61 00:02:53,630 --> 00:02:54,463 Lights off. 62 00:02:56,437 --> 00:02:58,550 (insects chirping) 63 00:02:58,550 --> 00:03:02,010 Long before Juno would make its daring attempt, 64 00:03:02,010 --> 00:03:03,940 scientists had begun to realize 65 00:03:03,940 --> 00:03:06,654 that it was an unusual region of space. 66 00:03:06,654 --> 00:03:08,070 (dramatic music) 67 00:03:08,070 --> 00:03:11,980 Back in 1955, they detected bursts of radio emission 68 00:03:11,980 --> 00:03:16,174 coming from Jupiter, and they didn't know what it was. 69 00:03:16,174 --> 00:03:17,330 (dramatic music) 70 00:03:17,330 --> 00:03:21,390 It's like a gigantic engine, and the amount of energy 71 00:03:21,390 --> 00:03:25,540 that must be just bopping around that thing is amazing. 72 00:03:25,540 --> 00:03:28,720 But this told us that Jupiter has a magnetic field, 73 00:03:28,720 --> 00:03:31,310 and perhaps, more importantly, a very strong one. 74 00:03:31,310 --> 00:03:33,660 Some planets have a dynamo inside, 75 00:03:33,660 --> 00:03:37,170 which means they behave like a giant spinning magnet 76 00:03:37,170 --> 00:03:39,850 surrounding them with a magnetic field. 77 00:03:39,850 --> 00:03:42,050 Early on, little was known about 78 00:03:42,050 --> 00:03:44,270 what these magnetic fields could do. 79 00:03:44,270 --> 00:03:47,440 Then in 1958, an experiment 80 00:03:47,440 --> 00:03:49,900 would begin to reveal the secret. 81 00:03:49,900 --> 00:03:50,733 At the end of the 1950s, 82 00:03:50,733 --> 00:03:53,100 there was a huge push in America 83 00:03:53,100 --> 00:03:55,910 to have a successful satellite in orbit, 84 00:03:55,910 --> 00:04:00,020 and the concept of the Explorer 1 mission was developed. 85 00:04:00,020 --> 00:04:01,700 Now the scientific payload for that mission 86 00:04:01,700 --> 00:04:04,270 was led by a person called James Van Allen, 87 00:04:04,270 --> 00:04:07,390 who had a big interest in magnetic fields 88 00:04:07,390 --> 00:04:10,130 and the particle environment 89 00:04:10,130 --> 00:04:13,070 that might be above our heads in space. 90 00:04:13,070 --> 00:04:14,360 (dramatic music) 91 00:04:14,360 --> 00:04:17,160 One of the things that he was excited about 92 00:04:17,160 --> 00:04:20,090 was really high-energy particles, 93 00:04:20,090 --> 00:04:23,850 and so he proposed an instrument to be on Explorer 1, 94 00:04:23,850 --> 00:04:25,433 our very first spacecraft. 95 00:04:33,630 --> 00:04:37,680 So Explorer 1 had a very simple detector system 96 00:04:37,680 --> 00:04:39,970 that would count particles. 97 00:04:39,970 --> 00:04:41,270 It was a Geiger-Muller tube, 98 00:04:41,270 --> 00:04:43,660 the kind of thing you look for radiation with. 99 00:04:43,660 --> 00:04:46,550 It does the click, click, click counting for radiation. 100 00:04:46,550 --> 00:04:48,060 They wanted to fly this on the rocket 101 00:04:48,060 --> 00:04:50,130 to measure the radiation up in space. 102 00:04:50,130 --> 00:04:52,340 The experiment was looking for cosmic rays. 103 00:04:52,340 --> 00:04:54,860 Now cosmic rays are the radiation coming out 104 00:04:54,860 --> 00:04:58,590 from far out in the galaxy entering our solar system. 105 00:04:58,590 --> 00:04:59,788 And it went up there. 106 00:04:59,788 --> 00:05:02,760 They're counting the particles, zip, zip, zip going in. 107 00:05:02,760 --> 00:05:06,283 At some point though, the signals disappeared. 108 00:05:06,283 --> 00:05:09,200 (machine whirring) 109 00:05:11,078 --> 00:05:12,610 At certain altitudes, 110 00:05:12,610 --> 00:05:14,850 particularly around about 2,000 kilometers 111 00:05:14,850 --> 00:05:16,290 above the surface of the Earth, 112 00:05:16,290 --> 00:05:17,840 the count rate dropped to zero. 113 00:05:17,840 --> 00:05:20,867 They thought, "Ah-ha, you know what's happening. 114 00:05:20,867 --> 00:05:22,457 "This is saturated. 115 00:05:22,457 --> 00:05:24,947 "The number of particles are so high 116 00:05:24,947 --> 00:05:28,659 "that the detector has just said I'm gonna shut down." 117 00:05:28,659 --> 00:05:30,920 (dramatic music) 118 00:05:30,920 --> 00:05:35,500 That realization actually led to a phenomenal discovery. 119 00:05:35,500 --> 00:05:40,150 In space there are donut shaped regions around the Earth 120 00:05:40,150 --> 00:05:43,500 where there are many, many electrically charged particles, 121 00:05:43,500 --> 00:05:44,960 for example, electrons 122 00:05:44,960 --> 00:05:47,550 and other electrically charged particles. 123 00:05:47,550 --> 00:05:50,220 The radiation gets trapped into this really 124 00:05:50,220 --> 00:05:51,923 lethal zone around the Earth. 125 00:05:53,400 --> 00:05:55,790 They're trapped because electrically charged particles 126 00:05:55,790 --> 00:05:59,420 feel a force from the magnetic field. 127 00:05:59,420 --> 00:06:01,260 We had discovered that the Earth's 128 00:06:01,260 --> 00:06:04,500 magnetic field creates a bubble around the planet 129 00:06:04,500 --> 00:06:06,130 called a magnetosphere sphere, 130 00:06:06,130 --> 00:06:08,760 that both deflects charged particles 131 00:06:08,760 --> 00:06:10,850 and captures some as well. 132 00:06:10,850 --> 00:06:13,060 Many of these particles of radiation 133 00:06:13,060 --> 00:06:15,330 come streaming from the sun, 134 00:06:15,330 --> 00:06:17,373 and this is called the solar wind. 135 00:06:18,620 --> 00:06:21,570 The scientific discovery is fantastic on the one hand, 136 00:06:21,570 --> 00:06:22,980 but it's also slightly worrying. 137 00:06:22,980 --> 00:06:26,730 Because high-energy charged particles can pack a punch 138 00:06:26,730 --> 00:06:28,270 when they interact with materials. 139 00:06:28,270 --> 00:06:31,760 So let's imagine, for example, the impact on the human body. 140 00:06:31,760 --> 00:06:33,950 If these particles have enough energy, 141 00:06:33,950 --> 00:06:35,980 they can penetrate the skin 142 00:06:35,980 --> 00:06:39,380 and start to interfere with the cells of the body. 143 00:06:39,380 --> 00:06:41,430 So in an extreme case, 144 00:06:41,430 --> 00:06:44,390 you might get radiation sickness if you had enough 145 00:06:44,390 --> 00:06:46,705 high-energy particles coming into your body. 146 00:06:46,705 --> 00:06:47,980 (dramatic music) 147 00:06:47,980 --> 00:06:51,490 We have to be really careful, not just because of humans, 148 00:06:51,490 --> 00:06:55,570 we don't want to be damage but also the electronics. 149 00:06:55,570 --> 00:07:00,420 So can we send our spacecraft to places like Jupiter? 150 00:07:00,420 --> 00:07:03,703 Will our spacecraft survive in those kind of environments? 151 00:07:03,703 --> 00:07:06,453 (dramatic music) 152 00:07:10,200 --> 00:07:12,240 When Van Allen discovered these incredibly 153 00:07:12,240 --> 00:07:14,270 high-energy radiation belts around the Earth, 154 00:07:14,270 --> 00:07:16,760 I think, people started to then look at the models 155 00:07:16,760 --> 00:07:18,750 of what would be needed at Jupiter 156 00:07:18,750 --> 00:07:21,070 to explain what was being observed? 157 00:07:21,070 --> 00:07:23,530 All of a sudden like pieces of a puzzle, 158 00:07:23,530 --> 00:07:25,630 the ideas started to come together. 159 00:07:25,630 --> 00:07:27,300 The calculations started to be made, 160 00:07:27,300 --> 00:07:29,660 and people were startled because Jupiter 161 00:07:29,660 --> 00:07:32,330 was so much more powerful than the Earth. 162 00:07:32,330 --> 00:07:34,780 I mean, our radiation belt, as severe as they are 163 00:07:34,780 --> 00:07:38,360 and dangerous as they may be, are really a piece of cake 164 00:07:38,360 --> 00:07:39,360 compared to Jupiter. 165 00:07:41,373 --> 00:07:43,956 (gentle music) 166 00:07:53,310 --> 00:07:55,720 So the first time we left Earth 167 00:07:55,720 --> 00:07:57,880 to go out in the solar system 168 00:07:57,880 --> 00:08:01,363 beyond the orbit of Mars, there were major concerns. 169 00:08:02,230 --> 00:08:05,120 Can we send a spacecraft through that environment? 170 00:08:05,120 --> 00:08:07,843 So we sent two Pioneer space rockets. 171 00:08:09,710 --> 00:08:11,150 They were pretty crude 172 00:08:11,150 --> 00:08:14,670 with very limited computational capabilities 173 00:08:14,670 --> 00:08:18,550 and very limited power and ability to communicate. 174 00:08:18,550 --> 00:08:20,710 So they would just make a few measurements, 175 00:08:20,710 --> 00:08:23,904 and then send the information back to the Earth very simple. 176 00:08:23,904 --> 00:08:27,321 (funky electronic music) 177 00:08:32,051 --> 00:08:33,870 So when the Pioneers flew 178 00:08:33,870 --> 00:08:35,950 through the magnetosphere of Jupiter, 179 00:08:35,950 --> 00:08:37,810 we didn't know how big this was. 180 00:08:37,810 --> 00:08:39,960 We didn't know how large the magnetic field is, 181 00:08:39,960 --> 00:08:41,620 and we didn't know how it was shaped 182 00:08:41,620 --> 00:08:43,793 or buffeted by the solar wind. 183 00:08:46,233 --> 00:08:47,580 (dramatic music) 184 00:08:47,580 --> 00:08:50,470 Pioneer 10 was due to fly past Jupiter 185 00:08:50,470 --> 00:08:53,840 on the 3rd of December 1973, 186 00:08:53,840 --> 00:08:58,195 and these are some of the first images it sent back. 187 00:08:58,195 --> 00:09:01,610 (dramatic music) 188 00:09:01,610 --> 00:09:03,800 Pioneer carried some protection, 189 00:09:03,800 --> 00:09:04,930 but it probably went a little bit 190 00:09:04,930 --> 00:09:06,560 closer than it should have. 191 00:09:06,560 --> 00:09:09,130 But it was zipping through pretty fast. 192 00:09:09,130 --> 00:09:11,580 In order to try to assess what it was like there, 193 00:09:11,580 --> 00:09:14,220 I mean, it basically was carrying a Geiger counter. 194 00:09:14,220 --> 00:09:15,690 I think, everybody was startled 195 00:09:15,690 --> 00:09:18,563 at the amount of energy that we're talking about. 196 00:09:20,170 --> 00:09:22,760 During its closest approach to Jupiter, 197 00:09:22,760 --> 00:09:26,050 Pioneer 10 absorbed 1,000 times 198 00:09:26,050 --> 00:09:29,610 the lethal dose of radiation for a human being. 199 00:09:29,610 --> 00:09:31,030 The spacecraft is collecting 200 00:09:31,030 --> 00:09:33,310 its worse radiation exposure. 201 00:09:33,310 --> 00:09:35,160 Tension is even greater this time 202 00:09:36,240 --> 00:09:37,951 and so is the relief. (people applauding) 203 00:09:37,951 --> 00:09:39,618 R-10, R-two. 204 00:09:40,682 --> 00:09:41,950 Makes it all worthwhile. 205 00:09:41,950 --> 00:09:44,720 After 10 years of having to put with all these people 206 00:09:44,720 --> 00:09:47,393 and 14 hours a day it's all worthwhile. 207 00:09:48,382 --> 00:09:49,900 (gentle music) 208 00:09:49,900 --> 00:09:53,630 And so, after the Pioneers we knew the extent 209 00:09:53,630 --> 00:09:58,113 of the Jovian magnetosphere, and it is enormous. 210 00:09:58,113 --> 00:10:00,863 (dramatic music) 211 00:10:04,490 --> 00:10:06,540 If we could see it in the night sky 212 00:10:06,540 --> 00:10:09,030 with Jupiter sitting rather far away from us, 213 00:10:09,030 --> 00:10:12,933 it would still be roughly five times larger than the moon. 214 00:10:14,700 --> 00:10:17,820 I always wished it could be like a light purple 215 00:10:17,820 --> 00:10:21,370 traveling through the sky, and it would just be huge. 216 00:10:21,370 --> 00:10:24,370 The solar wind that hits that magnetic field 217 00:10:24,370 --> 00:10:29,370 shapes it like a comet and produces a long tail. 218 00:10:29,430 --> 00:10:33,694 The tail stretches all the way to Saturn. 219 00:10:33,694 --> 00:10:36,444 (dramatic music) 220 00:10:37,660 --> 00:10:41,260 The primary purpose of those Pioneers was really to say 221 00:10:41,260 --> 00:10:44,400 can we survive this lethal dose of radiation, 222 00:10:44,400 --> 00:10:46,820 so then we can follow with more sophisticated 223 00:10:46,820 --> 00:10:49,748 instrumentation that can do a lot of interesting science. 224 00:10:49,748 --> 00:10:52,748 (lively drum music) 225 00:10:56,150 --> 00:10:58,880 I was lucky to start working on Voyager 226 00:10:58,880 --> 00:11:01,050 as a graduate student at MIT. 227 00:11:01,050 --> 00:11:03,173 It was the first project that I worked on. 228 00:11:04,680 --> 00:11:08,270 I came along just as we were about to launch the spacecraft 229 00:11:08,270 --> 00:11:10,163 on its way out first to Jupiter. 230 00:11:11,433 --> 00:11:13,870 I got a job as an undergraduate assistant 231 00:11:13,870 --> 00:11:15,270 to the imaging team. 232 00:11:15,270 --> 00:11:17,783 It was a mind blowing experience in so many ways. 233 00:11:18,980 --> 00:11:20,687 We had the Voyager spacecraft down 234 00:11:20,687 --> 00:11:22,630 at the Cape ready to launch. 235 00:11:22,630 --> 00:11:25,920 It was the Pioneer data that made us realize 236 00:11:25,920 --> 00:11:28,300 that the radiation tolerance that we had designed 237 00:11:28,300 --> 00:11:31,430 into the Voyager spacecraft was not gonna be adequate 238 00:11:31,430 --> 00:11:35,130 for the environment that Pioneer 10 and 11 had sensed. 239 00:11:35,130 --> 00:11:37,130 It threw us into a real turmoil 240 00:11:37,130 --> 00:11:38,977 of trying to recover from that. 241 00:11:38,977 --> 00:11:40,620 (funky guitar music) 242 00:11:40,620 --> 00:11:43,020 By the time we got to the Voyager spacecraft, 243 00:11:43,020 --> 00:11:45,570 we were already so scared and intimidated by Jupiter 244 00:11:45,570 --> 00:11:47,620 that we started to move away from it. 245 00:11:47,620 --> 00:11:48,970 We didn't wanna get so close 246 00:11:48,970 --> 00:11:51,320 because we knew if you got close, 247 00:11:51,320 --> 00:11:53,410 you're probably spelling the end of the spacecraft. 248 00:11:53,410 --> 00:11:56,520 So you've gotta stay away and respect this beast. 249 00:11:56,520 --> 00:11:59,793 This monster it's much more powerful than we are. 250 00:12:02,040 --> 00:12:05,520 Even with a quite small telescope from your backyard, 251 00:12:05,520 --> 00:12:08,200 you can look up and see Jupiter on a clear night, 252 00:12:08,200 --> 00:12:10,340 and you can see the belts and zones. 253 00:12:10,340 --> 00:12:12,263 You can see the red spot. 254 00:12:12,263 --> 00:12:14,980 (funky upbeat music) 255 00:12:14,980 --> 00:12:17,690 But Voyager saw up close 256 00:12:17,690 --> 00:12:20,510 and making a movie as it approached. 257 00:12:20,510 --> 00:12:23,593 (funky upbeat music) 258 00:12:24,720 --> 00:12:25,790 It was really like you were 259 00:12:25,790 --> 00:12:27,840 on the spacecraft looking out the window. 260 00:12:29,560 --> 00:12:32,010 You could see these belts and zones, 261 00:12:32,010 --> 00:12:34,420 east, west winds going back and forth, 262 00:12:34,420 --> 00:12:36,890 and the great red spot being caught up 263 00:12:36,890 --> 00:12:39,170 in those belts and zones. 264 00:12:39,170 --> 00:12:42,010 So the weather system was becoming clear. 265 00:12:42,010 --> 00:12:44,570 As we flew by, we could get a real sense 266 00:12:44,570 --> 00:12:47,660 of how this dynamic atmosphere was working. 267 00:12:55,037 --> 00:12:56,020 (gentle music) 268 00:12:56,020 --> 00:12:58,730 As we come in for a close view of Jupiter, 269 00:12:58,730 --> 00:13:01,640 you'll see clouds orbiting around the planet 270 00:13:01,640 --> 00:13:04,940 at different rates, with different thickness bands, 271 00:13:04,940 --> 00:13:07,130 and these are called the jets. 272 00:13:07,130 --> 00:13:10,470 These jets go around lines of latitude, back and forth, 273 00:13:10,470 --> 00:13:13,920 some faster than the planet, some slower than the planet, 274 00:13:13,920 --> 00:13:16,060 and so if you were living on the planet, 275 00:13:16,060 --> 00:13:19,500 there'd be these huge sheers at different latitudes 276 00:13:19,500 --> 00:13:23,460 as these fight back and forth in different directions. 277 00:13:23,460 --> 00:13:26,310 Finding out what causes this wild weather 278 00:13:26,310 --> 00:13:29,250 became a key scientific objective. 279 00:13:29,250 --> 00:13:32,900 On Jupiter the affects of planetary rotation 280 00:13:32,900 --> 00:13:34,850 are incredibly important, why? 281 00:13:34,850 --> 00:13:37,560 Well, the strength of the rotational forces 282 00:13:37,560 --> 00:13:40,060 depends on how fast the system rotates, 283 00:13:40,060 --> 00:13:43,180 and it also depends on how big the system is, 284 00:13:43,180 --> 00:13:44,773 and Jupiter's huge. 285 00:13:45,630 --> 00:13:50,030 Jupiter has a diameter of a 140,000 kilometers 286 00:13:50,030 --> 00:13:52,680 and it was discovered that the planets rotates 287 00:13:52,680 --> 00:13:55,333 at about 40,000 kilometers per hour. 288 00:13:56,389 --> 00:13:59,119 So this body is just completely flying. 289 00:13:59,119 --> 00:14:00,960 If you think of the whole planet as a gyroscope, 290 00:14:00,960 --> 00:14:03,660 it would be a very big, very fast gyroscope. 291 00:14:03,660 --> 00:14:06,430 Those gyroscopic effects dominate 292 00:14:06,430 --> 00:14:08,203 many of the dynamics we observed. 293 00:14:09,570 --> 00:14:13,010 We use this demo to explain Jupiter's great red spot, 294 00:14:13,010 --> 00:14:15,130 which is a really interesting phenomenon 295 00:14:15,130 --> 00:14:17,390 that we've observed for over 200 years, 296 00:14:17,390 --> 00:14:19,950 and we think it's existed longer than that. 297 00:14:19,950 --> 00:14:22,110 It's, essentially, a massive hurricane 298 00:14:22,110 --> 00:14:25,350 that's about 1.3 times the size of the Earth. 299 00:14:25,350 --> 00:14:26,910 In this experiment you're looking at 300 00:14:26,910 --> 00:14:30,400 a simplified analog of the surface of a gas giant. 301 00:14:30,400 --> 00:14:32,330 The cloud layer it's only about 302 00:14:32,330 --> 00:14:35,930 five or six centimeters deep and a meter across, 303 00:14:35,930 --> 00:14:38,750 and we faked the photo chemistry with 304 00:14:38,750 --> 00:14:41,198 sprayed in food coloring. 305 00:14:41,198 --> 00:14:42,610 (funky upbeat music) 306 00:14:42,610 --> 00:14:45,150 So Jupiter is very strongly rotating body, 307 00:14:45,150 --> 00:14:47,550 but it also has a lot of strong turbulence. 308 00:14:47,550 --> 00:14:49,590 The great red spot has formed 309 00:14:49,590 --> 00:14:52,490 from this rapidly rotating turbulence. 310 00:14:52,490 --> 00:14:55,100 Instead of having the massive turbulence 311 00:14:55,100 --> 00:14:57,070 that's naturally occurring in Jupiter 312 00:14:57,070 --> 00:15:00,637 by the hand of God, we just mix a little. 313 00:15:02,810 --> 00:15:04,930 As a cloud of gas or liquid 314 00:15:04,930 --> 00:15:07,480 moves across a rotating surface, 315 00:15:07,480 --> 00:15:11,360 its path begins to curve along with the rotation. 316 00:15:11,360 --> 00:15:13,590 This is called the Coriolis effect, 317 00:15:13,590 --> 00:15:17,540 and it's what spins hurricanes and typhoons here on Earth. 318 00:15:17,540 --> 00:15:21,460 But because Jupiter is so large and turns so fast, 319 00:15:21,460 --> 00:15:23,773 its weather is far more extreme. 320 00:15:24,920 --> 00:15:26,870 The affect of the Coriolis force 321 00:15:26,870 --> 00:15:28,800 in the presence of turbulence 322 00:15:28,800 --> 00:15:31,100 acts to generate large scale structures, 323 00:15:31,100 --> 00:15:33,493 like the great red spot, and they persist. 324 00:15:34,540 --> 00:15:37,380 But now what you're seeing in the tank 325 00:15:37,380 --> 00:15:41,560 is the formation of these beautiful vortices. 326 00:15:41,560 --> 00:15:44,400 You can see there's all these filaments connecting them. 327 00:15:44,400 --> 00:15:46,530 That's what you get in rotating systems. 328 00:15:46,530 --> 00:15:48,920 You naturally role things up 329 00:15:48,920 --> 00:15:51,735 into large vertical structures. 330 00:15:51,735 --> 00:15:54,040 (funky upbeat music) 331 00:15:54,040 --> 00:15:55,560 They live a long, long time 332 00:15:55,560 --> 00:15:57,743 when the system's rapidly rotating. 333 00:16:08,230 --> 00:16:10,270 If the planet stopped rotating, 334 00:16:10,270 --> 00:16:11,870 that organization would be gone. 335 00:16:18,002 --> 00:16:20,240 (dramatic music) 336 00:16:20,240 --> 00:16:22,110 The Voyager spacecraft were not 337 00:16:22,110 --> 00:16:26,150 just visiting Jupiter in order to examine the planet. 338 00:16:26,150 --> 00:16:30,400 The four giant Galilean moons were a key objective, 339 00:16:30,400 --> 00:16:34,261 and none more so than the mysterious moon Io. 340 00:16:34,261 --> 00:16:37,011 (dramatic music) 341 00:16:39,620 --> 00:16:41,030 As we were coming in, 342 00:16:41,030 --> 00:16:43,147 the ultraviolet instrument was saying, 343 00:16:43,147 --> 00:16:44,717 "Whoa, this is bright. 344 00:16:44,717 --> 00:16:48,657 "Whoa, there's a lot of gas around this environment near Io. 345 00:16:48,657 --> 00:16:50,458 "You better be careful." 346 00:16:50,458 --> 00:16:51,400 (dramatic music) 347 00:16:51,400 --> 00:16:55,723 Voyager flew by and we saw it covered with volcanoes. 348 00:16:57,890 --> 00:17:01,040 We saw gases spewing out 349 00:17:01,040 --> 00:17:03,863 hundreds of kilometers up into the sky, 350 00:17:08,240 --> 00:17:11,830 and so now we began to make sense what was happening. 351 00:17:11,830 --> 00:17:14,640 That these volcanoes were spewing out gases 352 00:17:14,640 --> 00:17:16,403 about a ton every second. 353 00:17:17,930 --> 00:17:21,490 Those gases were becoming trapped in the magnetic field 354 00:17:21,490 --> 00:17:24,400 to make this donut of charge particles. 355 00:17:24,400 --> 00:17:27,440 They get accelerated to very high energies. 356 00:17:27,440 --> 00:17:29,320 (dramatic music) 357 00:17:29,320 --> 00:17:32,620 Most of them go out to fill a big volume. 358 00:17:32,620 --> 00:17:35,190 Some of them go in, and as they go in, 359 00:17:35,190 --> 00:17:37,090 they go to even higher energies 360 00:17:37,090 --> 00:17:40,960 and form this very tight environment close to Jupiter, 361 00:17:40,960 --> 00:17:43,940 this lethal radiation environment. 362 00:17:43,940 --> 00:17:46,400 That inner region is very analogous 363 00:17:46,400 --> 00:17:48,860 to the Van Allen belt of Earth 364 00:17:48,860 --> 00:17:52,023 but many times stronger and more nasty. 365 00:17:54,360 --> 00:17:56,353 The background radiation here on Earth 366 00:17:56,353 --> 00:17:59,320 that we're exposed to is about a third of a rad. 367 00:17:59,320 --> 00:18:03,723 At Jupiter, the radiation environment is 20 million rad. 368 00:18:06,170 --> 00:18:08,760 We did know Io, Europa, Ganymede 369 00:18:08,760 --> 00:18:10,550 are in these orbital residences 370 00:18:10,550 --> 00:18:13,120 where Io goes around four times 371 00:18:13,120 --> 00:18:15,183 for every two times and one times 372 00:18:15,183 --> 00:18:16,820 that the others go around. 373 00:18:16,820 --> 00:18:18,310 The orbits are elliptical, 374 00:18:18,310 --> 00:18:22,120 and so when Io was close to Jupiter, it squeezes it. 375 00:18:22,120 --> 00:18:25,810 When it's further away from Jupiter, the squeeze is less, 376 00:18:25,810 --> 00:18:29,040 and so you're literally looking at Io going like this. 377 00:18:29,040 --> 00:18:31,423 That heat has got to go somewhere. 378 00:18:32,720 --> 00:18:36,290 There'd been a paper published in science magazine 379 00:18:36,290 --> 00:18:39,830 that had come out the week before Voyager got there 380 00:18:39,830 --> 00:18:42,975 predicting volcanoes on Io because of this tidal flexing. 381 00:18:42,975 --> 00:18:44,050 (dramatic music) 382 00:18:44,050 --> 00:18:48,601 But, we were not expecting what we saw with Voyager. 383 00:18:48,601 --> 00:18:53,601 (machine beeping) (gentle music) 384 00:18:53,720 --> 00:18:57,000 Everybody thought the Io was the cool neat one 385 00:18:57,000 --> 00:18:59,584 and the others were okay. 386 00:18:59,584 --> 00:19:02,167 (gentle music) 387 00:19:04,320 --> 00:19:06,020 We knew there was something weird about Europa. 388 00:19:06,020 --> 00:19:08,600 It was bright and maybe it had these weird markings, 389 00:19:08,600 --> 00:19:11,135 but you couldn't really see them before. 390 00:19:11,135 --> 00:19:14,100 (gentle music) 391 00:19:14,100 --> 00:19:15,747 Then all of sudden there it is, 392 00:19:15,747 --> 00:19:18,260 and this first image is appearing on the screen. 393 00:19:18,260 --> 00:19:20,230 Europa has all these cracks in the ice 394 00:19:20,230 --> 00:19:22,080 and these lines going across. 395 00:19:22,080 --> 00:19:23,420 They're gonna be two. 396 00:19:23,420 --> 00:19:24,810 Io and Europa there's a twin. 397 00:19:24,810 --> 00:19:27,330 At that moment it was just like whoa. 398 00:19:27,330 --> 00:19:28,885 What does that mean? 399 00:19:28,885 --> 00:19:31,420 (gentle music) 400 00:19:31,420 --> 00:19:33,260 As an airless body, we kind of expect 401 00:19:33,260 --> 00:19:35,390 things to be bombarded all the time, so you end up 402 00:19:35,390 --> 00:19:37,770 with a surface peppered with craters much like our moon. 403 00:19:37,770 --> 00:19:40,003 What about the relief in the cracks? 404 00:19:40,003 --> 00:19:42,760 Because the cratering rate throughout the solar system 405 00:19:42,760 --> 00:19:45,390 is relatively well understood, 406 00:19:45,390 --> 00:19:48,740 the fact that Europa has so few craters 407 00:19:48,740 --> 00:19:51,950 is very consistent with it having a young surface, 408 00:19:51,950 --> 00:19:55,103 with a surface that has been geologically resurfaced. 409 00:19:56,030 --> 00:19:57,600 Carl Sagan who was there in the room 410 00:19:57,600 --> 00:20:00,237 he said, "Ah, Percival Lowell was right. 411 00:20:00,237 --> 00:20:03,991 "Only the canals are on Europa not Mars." 412 00:20:03,991 --> 00:20:05,380 Now this is something we keep discovering 413 00:20:05,380 --> 00:20:06,720 in planetary science. 414 00:20:06,720 --> 00:20:08,370 We thought the moons of Jupiter would be 415 00:20:08,370 --> 00:20:10,140 all dead and boring, and they're not 416 00:20:10,140 --> 00:20:12,600 because there's a mysterious unknown energy sources. 417 00:20:12,600 --> 00:20:15,710 (scientists chatting) 418 00:20:15,710 --> 00:20:17,587 It's like, "Oh, wow, there's more going on here 419 00:20:17,587 --> 00:20:20,137 "than we thought with our Earth-based assumptions." 420 00:20:27,084 --> 00:20:28,630 (upbeat music) 421 00:20:28,630 --> 00:20:32,710 The Voyager observations were so spectacular, 422 00:20:32,710 --> 00:20:34,670 the dynamics of the atmosphere, 423 00:20:34,670 --> 00:20:37,580 the different kinds of moons and what was going on. 424 00:20:37,580 --> 00:20:39,840 Everybody said we gotta go back. 425 00:20:39,840 --> 00:20:42,370 But this time we have to go back and stay. 426 00:20:42,370 --> 00:20:44,220 With Voyager we had a couple of 427 00:20:44,220 --> 00:20:46,470 very short fleeting flybys. 428 00:20:46,470 --> 00:20:48,410 Like just whizzing some pictures 429 00:20:48,410 --> 00:20:50,460 out your car window as you drive by, 430 00:20:50,460 --> 00:20:52,100 as opposed to actually stopping, 431 00:20:52,100 --> 00:20:55,160 getting out of the car and exploring. 432 00:20:55,160 --> 00:20:58,320 We have to go into orbit send a probe into the atmosphere. 433 00:20:58,320 --> 00:21:00,150 Find out what it's like inside. 434 00:21:00,150 --> 00:21:01,440 Go past all the moons 435 00:21:01,440 --> 00:21:03,381 and look at them in different directions. 436 00:21:03,381 --> 00:21:04,670 (upbeat music) 437 00:21:04,670 --> 00:21:06,450 Before the Voyagers had Jupiter 438 00:21:06,450 --> 00:21:08,150 in their rear view mirrors, 439 00:21:08,150 --> 00:21:11,440 NASA had been building a spacecraft they intended 440 00:21:11,440 --> 00:21:14,630 to go into orbit around the giant planet. 441 00:21:14,630 --> 00:21:16,843 The mission was called Galileo. 442 00:21:18,550 --> 00:21:21,620 Galileo had a fitful start right from the very beginning 443 00:21:21,620 --> 00:21:24,430 about how exactly it was going to get to Jupiter. 444 00:21:24,430 --> 00:21:26,190 Galileo was scheduled to launch 445 00:21:26,190 --> 00:21:30,280 in January 1982 onboard the space shuttle. 446 00:21:30,280 --> 00:21:35,280 The launch date slips to '84, then '85, and then '86, 447 00:21:35,440 --> 00:21:38,250 and then the whole shuttle program 448 00:21:38,250 --> 00:21:40,272 suffered a terrible tragedy. 449 00:21:40,272 --> 00:21:43,030 (somber music) 450 00:21:43,030 --> 00:21:44,900 The spacecraft was down at the Cape. 451 00:21:44,900 --> 00:21:46,660 I can remember looking out the window 452 00:21:46,660 --> 00:21:48,050 of the Challenge launch. 453 00:21:48,050 --> 00:21:49,950 Challenge go with throttle up. 454 00:21:52,350 --> 00:21:54,820 The significance of that, of course, the loss of life 455 00:21:54,820 --> 00:21:57,220 and a disruption of the whole program, 456 00:21:57,220 --> 00:22:00,660 but to us was we didn't have a launch vehicle. 457 00:22:00,660 --> 00:22:02,550 And so, we packed up our spacecraft 458 00:22:02,550 --> 00:22:04,480 and took it back to California 459 00:22:04,480 --> 00:22:06,083 trying to figure out what to do. 460 00:22:07,500 --> 00:22:09,630 Not only was the launch delayed, 461 00:22:09,630 --> 00:22:11,070 but after the accident, 462 00:22:11,070 --> 00:22:14,630 NASA was understandably more risk averse. 463 00:22:14,630 --> 00:22:17,120 The liquid hydrogen fueled rocket booster, 464 00:22:17,120 --> 00:22:19,050 which was originally planned to deliver 465 00:22:19,050 --> 00:22:21,910 the Galileo mission directly to Jupiter, 466 00:22:21,910 --> 00:22:24,260 was no longer deemed safe enough. 467 00:22:24,260 --> 00:22:25,560 It was no longer possible 468 00:22:25,560 --> 00:22:28,313 to take Galileo straight up to Jupiter, 469 00:22:28,313 --> 00:22:29,990 and that's where the mission designers here 470 00:22:29,990 --> 00:22:31,210 pulled a rabbit out of the hat 471 00:22:31,210 --> 00:22:33,120 and found the so-called VEEGA, 472 00:22:33,120 --> 00:22:35,410 Venus Earth Earth Gravity Assist trajectory 473 00:22:35,410 --> 00:22:37,469 that took another five years to get there. 474 00:22:37,469 --> 00:22:39,780 (crowd applauding) 475 00:22:39,780 --> 00:22:41,910 We have a go from main engine start. 476 00:22:41,910 --> 00:22:46,570 Six, five, four, three, two, one. 477 00:22:47,673 --> 00:22:50,750 We have ignition and lift off of Atlantis 478 00:22:50,750 --> 00:22:53,926 and the Galileo spacecraft bound for Jupiter. 479 00:22:53,926 --> 00:22:55,606 (gentle music) 480 00:22:55,606 --> 00:22:58,773 (astronauts chatting) 481 00:23:04,580 --> 00:23:06,930 Galileo is on its way to another world. 482 00:23:08,210 --> 00:23:09,570 Fly safe. 483 00:23:09,570 --> 00:23:10,960 After the first flyby, 484 00:23:10,960 --> 00:23:14,170 we knew we would be far enough away from the sun 485 00:23:14,170 --> 00:23:16,697 that we could actually begin to use the high-gain antenna. 486 00:23:16,697 --> 00:23:18,978 (gentle music) 487 00:23:18,978 --> 00:23:20,250 It was like an umbrella. 488 00:23:20,250 --> 00:23:22,160 You imagine an umbrella being folded up. 489 00:23:22,160 --> 00:23:23,800 Then when the time came 490 00:23:23,800 --> 00:23:25,720 when the spacecraft would fire a device, 491 00:23:25,720 --> 00:23:27,910 and then the antenna could unfold. 492 00:23:27,910 --> 00:23:31,690 So we accentuated the motor to free the antenna 493 00:23:32,890 --> 00:23:34,281 and it stuck. 494 00:23:34,281 --> 00:23:36,860 (bright music) 495 00:23:36,860 --> 00:23:39,300 If you imagine. (imitates machine whirring) 496 00:23:39,300 --> 00:23:42,431 It stalled only partially deploying some of the antenna. 497 00:23:42,431 --> 00:23:43,750 (bright flute music) 498 00:23:43,750 --> 00:23:45,053 The motor doesn't reverse. 499 00:23:47,130 --> 00:23:49,930 We could tell the antenna had deployed a little bit 500 00:23:49,930 --> 00:23:52,830 because the spacecraft's spin wasn't quite the same. 501 00:23:52,830 --> 00:23:54,380 It's like if you stick out one arm and you're spinning 502 00:23:54,380 --> 00:23:56,350 you start to do this a little bit. 503 00:23:56,350 --> 00:23:57,370 Well, the antenna was doing that a little bit. 504 00:23:57,370 --> 00:23:59,340 So we knew it opened some. 505 00:23:59,340 --> 00:24:00,490 So why didn't it open? 506 00:24:00,490 --> 00:24:03,000 Well, we understand now that the reason it didn't open 507 00:24:03,000 --> 00:24:05,440 was because of the combination of the fact that 508 00:24:05,440 --> 00:24:07,933 the antenna had remained stowed for so long, 509 00:24:09,454 --> 00:24:10,523 and the fact that it went in 510 00:24:10,523 --> 00:24:12,810 from two vibrations environments. 511 00:24:12,810 --> 00:24:16,370 Once when we latched this spacecraft up in California, 512 00:24:16,370 --> 00:24:18,520 trucked it down the Kennedy. 513 00:24:18,520 --> 00:24:19,680 Challenger didn't work. 514 00:24:19,680 --> 00:24:20,760 Put it back in the truck. 515 00:24:20,760 --> 00:24:22,510 Trucked it back to Pasadena. 516 00:24:22,510 --> 00:24:23,897 Said, "Let's not mess with that antenna. 517 00:24:23,897 --> 00:24:25,317 "It was all put together right. 518 00:24:25,317 --> 00:24:27,220 "We'll just leave it the way it was." 519 00:24:27,220 --> 00:24:28,160 Back to Cape again. 520 00:24:28,160 --> 00:24:30,450 So it made three trips across the Cape 521 00:24:30,450 --> 00:24:32,767 in a truck which was vibrating the whole time. 522 00:24:32,767 --> 00:24:34,766 (bright music) 523 00:24:34,766 --> 00:24:35,940 And so, we did a lot of things. 524 00:24:35,940 --> 00:24:38,870 We worked on calibrating how far the antenna was open. 525 00:24:38,870 --> 00:24:40,670 Could we use it the way it was, 526 00:24:40,670 --> 00:24:43,070 and could we do the cold turns to free it up 527 00:24:43,070 --> 00:24:44,550 and see if anything springs free? 528 00:24:44,550 --> 00:24:47,460 We'd know again by seeing the spin rates change 529 00:24:47,460 --> 00:24:48,790 if anything broke free. 530 00:24:48,790 --> 00:24:51,803 So we spent a couple of years working on those things. 531 00:24:52,720 --> 00:24:54,350 JPL never did get 532 00:24:54,350 --> 00:24:56,170 the high-gain antenna to open. 533 00:24:57,870 --> 00:24:59,400 Our capability at Jupiter 534 00:24:59,400 --> 00:25:00,830 with an antenna that hadn't opened 535 00:25:00,830 --> 00:25:04,940 was gonna be dependent upon a single low-gain antenna. 536 00:25:04,940 --> 00:25:06,770 That just meant we had to transmit 537 00:25:06,770 --> 00:25:09,040 a lot fewer picture over the same time. 538 00:25:09,040 --> 00:25:11,940 But, overall reduction and mission return 539 00:25:11,940 --> 00:25:15,195 was large but not disastrous. 540 00:25:15,195 --> 00:25:17,945 (dramatic music) 541 00:25:19,460 --> 00:25:23,320 The Galileo spacecraft carried along with it a probe. 542 00:25:23,320 --> 00:25:25,470 It's sort of like this size. 543 00:25:25,470 --> 00:25:28,153 It had a big heat shield to protect it around it. 544 00:25:29,380 --> 00:25:33,150 In July 1995, we launched that probe 545 00:25:33,150 --> 00:25:35,067 and sent it in the direction of Jupiter. 546 00:25:35,067 --> 00:25:36,320 Now it didn't have engines, 547 00:25:36,320 --> 00:25:39,230 so we weren't guiding it and saying go there. 548 00:25:39,230 --> 00:25:42,383 We just sort of sent it on a trajectory towards Jupiter. 549 00:25:43,500 --> 00:25:47,720 Five months later on the 7th of December 1995, 550 00:25:47,720 --> 00:25:51,452 the Galileo probe was due to arrive at Jupiter. 551 00:25:51,452 --> 00:25:54,590 (dramatic music) 552 00:25:54,590 --> 00:25:57,950 There were no cameras onboard only censors 553 00:25:57,950 --> 00:25:59,740 and a little probe that was going to have 554 00:25:59,740 --> 00:26:02,803 an extremely violent introduction to Jupiter. 555 00:26:04,272 --> 00:26:06,370 It was coming in at something like 556 00:26:06,370 --> 00:26:09,879 a 130,000 miles an hour 557 00:26:09,879 --> 00:26:12,120 because it was pulled in by the gravity of Jupiter, 558 00:26:12,120 --> 00:26:13,753 and we had to slow it down. 559 00:26:15,680 --> 00:26:18,950 This heat shield heated up to about three times 560 00:26:18,950 --> 00:26:21,028 the temperature of the surface of the Sun. 561 00:26:21,028 --> 00:26:24,320 (dramatic music) 562 00:26:24,320 --> 00:26:26,610 During its maximum deceleration 563 00:26:26,610 --> 00:26:31,220 the probe endured forces of 228-Gs. 564 00:26:31,220 --> 00:26:33,993 Then eventually we kicked off that heat shield, 565 00:26:35,110 --> 00:26:36,743 put up some parachutes, 566 00:26:39,030 --> 00:26:40,540 and so as it went down, 567 00:26:40,540 --> 00:26:43,850 we were able to get a sense of what it was like. 568 00:26:45,468 --> 00:26:50,027 What we were expecting was three separate layers of clouds. 569 00:26:50,027 --> 00:26:52,777 (dramatic music) 570 00:26:54,506 --> 00:26:57,317 And we went down it was like, "Where are the clouds? 571 00:26:57,317 --> 00:26:58,150 "Where are the clouds? 572 00:26:58,150 --> 00:27:01,080 "We're not seeing the clouds what's going on?" 573 00:27:01,080 --> 00:27:03,553 So everybody was completely confused. 574 00:27:04,430 --> 00:27:07,270 Well, the hint came from the ground. 575 00:27:07,270 --> 00:27:10,120 Telescopes on Earth were looking in the infrared 576 00:27:10,120 --> 00:27:12,830 at Jupiter at the same time we sent the probe in. 577 00:27:12,830 --> 00:27:17,010 We realized that the probe went into a hot spot 578 00:27:17,010 --> 00:27:19,393 somewhere where there's very little water. 579 00:27:20,490 --> 00:27:22,920 I think, we realize that our whole idea 580 00:27:22,920 --> 00:27:25,550 of exploring these planets with single probes 581 00:27:25,550 --> 00:27:28,450 is a little bit susceptible to going into the wrong place. 582 00:27:29,750 --> 00:27:34,530 By the time the probe had got down to about 160 kilometers 583 00:27:34,530 --> 00:27:37,360 something like 23 times atmospheric pressure, 584 00:27:37,360 --> 00:27:40,310 it was now starting to get really hot, 585 00:27:40,310 --> 00:27:42,440 and so at that point the electronics 586 00:27:42,440 --> 00:27:44,380 is just not working anymore. 587 00:27:44,380 --> 00:27:48,423 It stops communicating and sending signals back to Earth. 588 00:27:49,880 --> 00:27:51,660 What happened to it after that? 589 00:27:51,660 --> 00:27:55,213 Well, it was so hot that it basically vaporized. 590 00:27:57,830 --> 00:28:00,210 But let's imagine what it will be like 591 00:28:00,210 --> 00:28:04,416 if you could be a pressured capsule as you get deeper down. 592 00:28:04,416 --> 00:28:05,400 (thunder rumbling) 593 00:28:05,400 --> 00:28:07,560 I mean, it's either a hang glider's nightmare 594 00:28:07,560 --> 00:28:11,253 or his dream depending on how risky they wanna be. 595 00:28:12,595 --> 00:28:13,900 But as you went deeper and deeper, 596 00:28:13,900 --> 00:28:17,010 it would get a little calmer, a little less turbulent. 597 00:28:17,010 --> 00:28:19,473 The pressure would get higher and higher. 598 00:28:20,848 --> 00:28:22,873 It's so hot everything's vaporous. 599 00:28:24,450 --> 00:28:25,910 Eventually, you get down to material 600 00:28:25,910 --> 00:28:27,490 that are almost like rock clouds, 601 00:28:27,490 --> 00:28:30,020 and they're probably precipitating. 602 00:28:30,020 --> 00:28:34,150 Now when you get down something like 10% of the radius, 603 00:28:34,150 --> 00:28:37,000 you're now getting to the point where the pressures 604 00:28:37,000 --> 00:28:41,380 are about a million times Earth's atmospheric pressure, 605 00:28:41,380 --> 00:28:44,100 and the density is getting really high. 606 00:28:44,100 --> 00:28:48,550 At that point hydrogen changes its phase. 607 00:28:48,550 --> 00:28:50,800 It's no longer molecules, 608 00:28:50,800 --> 00:28:53,710 protons and electrons connected together. 609 00:28:53,710 --> 00:28:57,490 But the protons and the electrons are moving separately, 610 00:28:57,490 --> 00:28:59,630 and it becomes metallic. 611 00:28:59,630 --> 00:29:02,520 That is it becomes electrically conducting. 612 00:29:02,520 --> 00:29:05,480 In this region you can generate a magnetic field, 613 00:29:05,480 --> 00:29:07,230 what's called a dynamo. 614 00:29:07,230 --> 00:29:10,530 The fluids convert some of their motional energy 615 00:29:10,530 --> 00:29:13,576 into magnetic field energy, into currents. 616 00:29:13,576 --> 00:29:16,520 (dramatic music) 617 00:29:16,520 --> 00:29:19,060 On Earth the dynamo is very far from us. 618 00:29:19,060 --> 00:29:21,940 Earth's core is halfway through the planet. 619 00:29:21,940 --> 00:29:25,020 But on Jupiter you don't even go 10% of the way in, 620 00:29:25,020 --> 00:29:28,600 and you've got this 60,000 kilometer radius ball 621 00:29:28,600 --> 00:29:32,241 of molten metallic material. 622 00:29:32,241 --> 00:29:35,690 (dramatic music) 623 00:29:35,690 --> 00:29:37,540 Maybe that means it's not amazing 624 00:29:37,540 --> 00:29:40,640 that you generate a huge magnetic field. 625 00:29:40,640 --> 00:29:43,340 I suspect it would look like Mercury. 626 00:29:43,340 --> 00:29:46,827 A glob of Mercury is what it will probably look like. 627 00:29:46,827 --> 00:29:48,770 (dramatic music) 628 00:29:48,770 --> 00:29:50,980 If you existed, you would be 629 00:29:50,980 --> 00:29:53,403 unbelievably thin, flat out pancake. 630 00:29:54,760 --> 00:29:57,660 You get to the center of Jupiter we're talking 631 00:29:57,660 --> 00:30:00,720 four times the temperature of the surface of the Sun, 632 00:30:00,720 --> 00:30:04,040 50 millions atmospheres pressure, 633 00:30:04,040 --> 00:30:07,330 and a density that's denser than the heaviest 634 00:30:07,330 --> 00:30:09,413 metals that we have on Earth. 635 00:30:11,960 --> 00:30:13,490 Now the Galileo probe 636 00:30:13,490 --> 00:30:15,360 had succeeded with its mission 637 00:30:15,360 --> 00:30:18,630 and subsequently vaporized inside Jupiter, 638 00:30:18,630 --> 00:30:21,430 the mothership had to avoid a similar fate 639 00:30:21,430 --> 00:30:24,280 and insert itself safely into orbit. 640 00:30:24,280 --> 00:30:26,610 In just that first pass when we were getting into orbit, 641 00:30:26,610 --> 00:30:29,280 Galileo received half of its radiation dose, 642 00:30:29,280 --> 00:30:32,340 like a 150 kilo rads in one shot. 643 00:30:32,340 --> 00:30:35,880 Then it went out further and kind of licked its wounds. 644 00:30:35,880 --> 00:30:38,850 Because of Galileo having this broken antenna, 645 00:30:38,850 --> 00:30:41,670 it meant that we couldn't make all the observations 646 00:30:41,670 --> 00:30:44,920 of Jupiter that we wanted, the movies and so on so forth. 647 00:30:44,920 --> 00:30:46,380 We had to be selective. 648 00:30:46,380 --> 00:30:47,780 Remembering that we don't wanna get 649 00:30:47,780 --> 00:30:49,660 into the radiation belts too quickly, 650 00:30:49,660 --> 00:30:53,120 so we tended to focus further out first. 651 00:30:53,120 --> 00:30:55,950 The first really exciting thing we found 652 00:30:55,950 --> 00:31:00,420 was Ganymede has its own magnetic field. 653 00:31:00,420 --> 00:31:01,570 The seventh moon out 654 00:31:01,570 --> 00:31:03,210 from the surface of Jupiter, 655 00:31:03,210 --> 00:31:06,930 Ganymede, is a moon the size of a planet. 656 00:31:06,930 --> 00:31:08,153 Larger than Mercury, 657 00:31:08,153 --> 00:31:10,800 it's the biggest moon in our solar system. 658 00:31:10,800 --> 00:31:13,610 The fact that Ganymede has a magnetic field, 659 00:31:13,610 --> 00:31:15,890 means that it might have some ability 660 00:31:15,890 --> 00:31:19,280 to protect itself from the harsh radiation of Jupiter, 661 00:31:19,280 --> 00:31:22,603 a key attribute for a habitat where life might be found. 662 00:31:23,450 --> 00:31:25,280 So now it starts to open up 663 00:31:25,280 --> 00:31:27,963 how we think about even what's a planetary body? 664 00:31:29,480 --> 00:31:32,680 These moons how different are they from other planets? 665 00:31:32,680 --> 00:31:34,991 They can have their own magnetic field. 666 00:31:34,991 --> 00:31:37,741 (dramatic music) 667 00:31:39,780 --> 00:31:42,060 But now the Galileo spacecraft, 668 00:31:42,060 --> 00:31:45,370 despite its troubles, was about to make arguably 669 00:31:45,370 --> 00:31:49,530 the most important discovery in the history of space flight 670 00:31:49,530 --> 00:31:51,600 at the mysterious moon that Voyager 671 00:31:51,600 --> 00:31:55,143 had visited 17 years before Europa. 672 00:31:56,846 --> 00:31:58,600 What we measured as we flew by 673 00:31:58,600 --> 00:32:00,360 was something quite remarkable. 674 00:32:00,360 --> 00:32:02,490 There were electrical currents 675 00:32:02,490 --> 00:32:05,140 that were flowing inside the moon 676 00:32:05,140 --> 00:32:07,283 that perturbed the magnetic field, 677 00:32:09,120 --> 00:32:12,403 and we concluded that Europa has to have 678 00:32:12,403 --> 00:32:14,852 a liquid ocean underneath that ice. 679 00:32:14,852 --> 00:32:17,602 (dramatic music) 680 00:32:21,008 --> 00:32:25,120 The reason is, ice is not very electrically conducting. 681 00:32:25,120 --> 00:32:29,260 You need it to be liquified as water in a big ocean 682 00:32:29,260 --> 00:32:31,293 to carry those electrical currents. 683 00:32:33,080 --> 00:32:35,400 Probably has to have salt in it 684 00:32:35,400 --> 00:32:36,510 to be electrically conducting 685 00:32:36,510 --> 00:32:39,000 in the way that the Earth's salty ocean 686 00:32:39,000 --> 00:32:41,080 is electrically conducting. 687 00:32:41,080 --> 00:32:44,220 The reason why we hardly see any craters 688 00:32:44,220 --> 00:32:46,130 on the surface of Europa, 689 00:32:46,130 --> 00:32:48,820 is because that ocean is squirted out 690 00:32:48,820 --> 00:32:51,640 and has filled them in over time. 691 00:32:51,640 --> 00:32:53,860 Like Io, Europa, 692 00:32:53,860 --> 00:32:56,380 which is also in an elliptical orbit 693 00:32:56,380 --> 00:32:59,790 gets squeezed and relaxed every two or so days 694 00:32:59,790 --> 00:33:02,350 as it goes around the planet, 695 00:33:02,350 --> 00:33:06,630 is dissipating that heat by melting that ice shell. 696 00:33:06,630 --> 00:33:10,420 We believe the ocean can be as thick as a 100 miles 697 00:33:10,420 --> 00:33:11,970 and maybe even thicker. 698 00:33:11,970 --> 00:33:15,740 At the rocky surface at the bottom of the ocean, 699 00:33:15,740 --> 00:33:18,620 I know exactly what it looks like. 700 00:33:18,620 --> 00:33:20,033 It looks like Io. 701 00:33:21,990 --> 00:33:25,540 We call those molten volcanoes on Io, 702 00:33:25,540 --> 00:33:28,700 but underneath the ocean in Europa 703 00:33:28,700 --> 00:33:31,463 we would call them hydrothermal vents. 704 00:33:33,000 --> 00:33:35,773 Such vents are also found here on Earth. 705 00:33:36,870 --> 00:33:39,870 Those hydrothermal vents form fields. 706 00:33:39,870 --> 00:33:41,640 So it's not just a single chimney. 707 00:33:41,640 --> 00:33:43,760 But there's a field of chimneys, if you like, 708 00:33:43,760 --> 00:33:45,730 and those fields we think on the early Earth, 709 00:33:45,730 --> 00:33:47,360 and potentially on some moons, 710 00:33:47,360 --> 00:33:49,920 could spread across an entire sea floor 711 00:33:49,920 --> 00:33:50,977 the ones we're interested in, 712 00:33:50,977 --> 00:33:52,980 and they are not black smokers, 713 00:33:52,980 --> 00:33:55,220 which are kind of chimneys with black smoke 714 00:33:55,220 --> 00:33:56,710 belching out of the top. 715 00:33:56,710 --> 00:33:58,730 It's a different type of vent. 716 00:33:58,730 --> 00:34:03,730 The hydrothermal fluid are warm, not hot, and alkaline. 717 00:34:03,860 --> 00:34:05,393 They look almost deserted. 718 00:34:06,310 --> 00:34:08,403 But they are chemically active. 719 00:34:09,410 --> 00:34:11,630 You have this kind of porous lathering 720 00:34:11,630 --> 00:34:13,790 sort of interconnected pores. 721 00:34:13,790 --> 00:34:15,580 Sort of hydrogen from the vents 722 00:34:15,580 --> 00:34:17,800 mixing with CO2 from the oceans, 723 00:34:17,800 --> 00:34:19,750 making organic molecules. 724 00:34:19,750 --> 00:34:22,800 Here you have a setting which looks an awful lot 725 00:34:22,800 --> 00:34:24,820 like the way that modern cells work. 726 00:34:26,820 --> 00:34:29,100 This kind of chemistry was almost certainly behind 727 00:34:29,100 --> 00:34:31,121 the origin of life on Earth. 728 00:34:31,121 --> 00:34:33,477 (liquid sloshing) 729 00:34:33,477 --> 00:34:36,560 (gentle piano music) 730 00:34:37,400 --> 00:34:40,780 When you look at Europa and you look at the cracks, 731 00:34:40,780 --> 00:34:42,720 there is this brown gunky stuff 732 00:34:42,720 --> 00:34:45,373 that seems to be coming from the interior. 733 00:34:46,700 --> 00:34:51,090 But also could it be that there's a source of chemistry 734 00:34:51,090 --> 00:34:53,660 coming from Io, in Io's volcanoes, 735 00:34:53,660 --> 00:34:57,640 impacting the surface of Europa bringing sulfur, 736 00:34:57,640 --> 00:35:01,300 and perhaps more importantly oxygen, into Europa, 737 00:35:01,300 --> 00:35:05,050 and that material then gets carried down into the ocean, 738 00:35:05,050 --> 00:35:08,240 oxidizing the environment of the ocean, 739 00:35:08,240 --> 00:35:12,510 and maybe enhancing the life that maybe is there. 740 00:35:12,510 --> 00:35:14,150 Maybe not, we don't know. 741 00:35:15,250 --> 00:35:18,900 I think that Europa is a place where, 742 00:35:18,900 --> 00:35:20,680 given what we think we know about life, 743 00:35:20,680 --> 00:35:21,650 there ought to be life. 744 00:35:21,650 --> 00:35:23,760 But it is the most likely place. 745 00:35:23,760 --> 00:35:26,030 If you wanna go somewhere in the solar system, 746 00:35:26,030 --> 00:35:30,156 to find out if there's life, that's where I'd put my money. 747 00:35:30,156 --> 00:35:33,020 After the incredible discovery at Europa, 748 00:35:33,020 --> 00:35:35,510 the Galileo mission found that Ganymede 749 00:35:35,510 --> 00:35:37,958 also had a sub-surface ocean, 750 00:35:37,958 --> 00:35:39,550 and there's was strong suspicions 751 00:35:39,550 --> 00:35:42,650 that Callisto might contain an ocean as well. 752 00:35:42,650 --> 00:35:44,650 We had no idea that life could exist 753 00:35:44,650 --> 00:35:46,550 anywhere else in our solar system prior to this. 754 00:35:46,550 --> 00:35:48,450 It was just we have life on Earth, 755 00:35:48,450 --> 00:35:50,810 so to get life anywhere else you need to have planets, 756 00:35:50,810 --> 00:35:53,340 and other star systems that look just like Earth. 757 00:35:53,340 --> 00:35:55,330 I think, we're realizing now that there 758 00:35:55,330 --> 00:35:57,880 are other places even within our solar system 759 00:35:57,880 --> 00:36:00,120 that you can have these right ingredients 760 00:36:00,120 --> 00:36:03,160 and have energy and these primordial ingredients 761 00:36:03,160 --> 00:36:06,380 that is required to actually make something complex 762 00:36:06,380 --> 00:36:08,631 out of randomness, essentially. 763 00:36:08,631 --> 00:36:11,300 (dramatic music) 764 00:36:11,300 --> 00:36:13,820 Galileo made a lot of incredible contributions 765 00:36:13,820 --> 00:36:15,780 to our understanding the whole system 766 00:36:15,780 --> 00:36:18,040 and how it interacts with each other. 767 00:36:18,040 --> 00:36:21,940 What was really going on as Io spit out all this material, 768 00:36:21,940 --> 00:36:23,840 Ganymede had its own magnetic feel. 769 00:36:23,840 --> 00:36:26,150 Europa had an enormous ocean. 770 00:36:26,150 --> 00:36:28,910 But by then we'd kind of done 771 00:36:28,910 --> 00:36:31,260 what we were gonna do with Galileo. 772 00:36:31,260 --> 00:36:32,290 The radiation of Jupiter 773 00:36:32,290 --> 00:36:34,490 is very, very hard on electronics. 774 00:36:34,490 --> 00:36:35,910 So it upset the spacecraft. 775 00:36:35,910 --> 00:36:38,150 It goes into saving, stops all the sequences, 776 00:36:38,150 --> 00:36:40,470 and you have to restart things. 777 00:36:40,470 --> 00:36:43,710 After having its mission extended three times, 778 00:36:43,710 --> 00:36:46,690 it was eventually decided in 2003 779 00:36:46,690 --> 00:36:50,810 to dispose of the aging radiation damaged spacecraft 780 00:36:50,810 --> 00:36:53,153 by flying it into the clouds of Jupiter. 781 00:36:57,820 --> 00:37:00,130 We learned so much from Galileo. 782 00:37:00,130 --> 00:37:03,380 In fact, it was really the results of Galileo 783 00:37:03,380 --> 00:37:05,090 that led us to Juno. 784 00:37:05,090 --> 00:37:08,420 Lift off of the Atlas V with Juno 785 00:37:08,420 --> 00:37:10,120 on a trek to Jupiter. 786 00:37:10,120 --> 00:37:12,520 The big question after Galileo 787 00:37:12,520 --> 00:37:15,930 was did not probe just go into somewhere weird 788 00:37:15,930 --> 00:37:20,930 or was the lack of water symptomatic of the entire planet? 789 00:37:21,610 --> 00:37:23,870 Now this is extremely important. 790 00:37:23,870 --> 00:37:25,640 In 30 minutes that it took the probe 791 00:37:25,640 --> 00:37:28,120 to go into Jupiter and get this data, 792 00:37:28,120 --> 00:37:31,720 every theory of solar system formation was proven wrong. 793 00:37:31,720 --> 00:37:34,960 Because remember we think that gas giants formed by having 794 00:37:34,960 --> 00:37:39,030 giant snowballs, say 30 times the mass of the Earth, 795 00:37:39,030 --> 00:37:42,660 that pull in the hydrogen to make the gas giants. 796 00:37:42,660 --> 00:37:46,040 So at the core we think there was ice. 797 00:37:46,040 --> 00:37:49,000 Yet, when we went in with that probe, 798 00:37:49,000 --> 00:37:51,440 we didn't see any or very little. 799 00:37:51,440 --> 00:37:52,460 So what's going on? 800 00:37:52,460 --> 00:37:54,020 So when Juno came along, 801 00:37:54,020 --> 00:37:55,590 one of its primary objectives 802 00:37:55,590 --> 00:37:58,540 was to go in and see how much water 803 00:37:58,540 --> 00:38:00,560 and oxygen is in Jupiter. 804 00:38:00,560 --> 00:38:03,330 We have to go back and find out. 805 00:38:03,330 --> 00:38:05,050 We could send in a 100 probes. 806 00:38:05,050 --> 00:38:07,343 But, that's gonna be expensive and difficult. 807 00:38:08,260 --> 00:38:10,777 We thought of a cleverer way of doing it. 808 00:38:10,777 --> 00:38:12,980 (dramatic music) 809 00:38:12,980 --> 00:38:16,180 Juno was designed in order to make measurements 810 00:38:16,180 --> 00:38:18,860 almost over the whole planet and look at the water 811 00:38:18,860 --> 00:38:20,303 rather than in one spot, 812 00:38:21,430 --> 00:38:24,913 and to go much deeper remotely not with a probe. 813 00:38:27,610 --> 00:38:31,363 The brilliant idea was to use microwaves. 814 00:38:32,260 --> 00:38:36,423 Everyone knows that microwaves are absorbed by water. 815 00:38:37,290 --> 00:38:40,860 So what we want to do is fly over Jupiter 816 00:38:40,860 --> 00:38:44,100 and map out the distribution of water 817 00:38:44,100 --> 00:38:46,960 from the absorption of those microwaves. 818 00:38:46,960 --> 00:38:49,800 But to find out what it's like deep inside, 819 00:38:49,800 --> 00:38:52,900 we have to measure distribution of mass inside 820 00:38:52,900 --> 00:38:56,173 that changes the gravity field in some subtle ways. 821 00:38:57,400 --> 00:38:59,870 To do that we had to go into a polar orbit, 822 00:38:59,870 --> 00:39:02,643 and we also had to get really close. 823 00:39:04,730 --> 00:39:07,440 Now remember we've got a problem with Jupiter. 824 00:39:07,440 --> 00:39:10,160 Jupiter has these radiation belts around it. 825 00:39:10,160 --> 00:39:12,740 You don't really wanna take your sensitive electronics 826 00:39:12,740 --> 00:39:15,120 of your spacecraft through that environment, 827 00:39:15,120 --> 00:39:16,253 at least not for long. 828 00:39:18,010 --> 00:39:21,250 We had to somehow get beneath the radiation belt. 829 00:39:21,250 --> 00:39:23,355 If we can just thread that needle. 830 00:39:23,355 --> 00:39:26,530 (dramatic music) 831 00:39:26,530 --> 00:39:28,680 I was just praying with my eyes closed 832 00:39:29,610 --> 00:39:31,053 that this was gonna work. 833 00:39:32,570 --> 00:39:36,360 We were getting a few thousand miles above the cloud tops 834 00:39:36,360 --> 00:39:38,010 when we were doing this maneuver. 835 00:39:38,960 --> 00:39:40,883 Nothing had ever been that close. 836 00:39:43,235 --> 00:39:44,413 Fire the engines. 837 00:39:45,780 --> 00:39:47,130 Go head now. 838 00:39:47,130 --> 00:39:49,353 Yeah, we see the action has started. 839 00:39:49,353 --> 00:39:50,881 Copy that, that's good news for us. 840 00:39:50,881 --> 00:39:51,870 (people applauding) Thirty-five minutes 841 00:39:51,870 --> 00:39:54,543 they're firing away slowing down the spacecraft, 842 00:39:55,470 --> 00:39:57,605 so it gets caught in Jupiter's gravity. 843 00:39:57,605 --> 00:40:00,355 (dramatic music) 844 00:40:03,580 --> 00:40:08,580 And when we find out spacecraft's alive, phew, big relief. 845 00:40:09,829 --> 00:40:12,609 (people applauding and cheering) 846 00:40:12,609 --> 00:40:15,235 Juno welcome to Jupiter. 847 00:40:15,235 --> 00:40:17,344 (dramatic music) 848 00:40:17,344 --> 00:40:18,969 NASA did it again. 849 00:40:18,969 --> 00:40:22,969 (crowd applauding and cheering) 850 00:40:27,087 --> 00:40:29,220 You know the thing that was also sobering 851 00:40:29,220 --> 00:40:32,360 was we were coming back, this was our game plan. 852 00:40:32,360 --> 00:40:33,950 Every orbit we were gonna have to 853 00:40:33,950 --> 00:40:36,000 run through that fire with our bare feet. 854 00:40:37,350 --> 00:40:40,710 Juno carried a camera called Juno cam 855 00:40:40,710 --> 00:40:44,520 designed to provide pictures for the public back on Earth. 856 00:40:44,520 --> 00:40:48,580 But these images were too reveal a great surprise. 857 00:40:48,580 --> 00:40:52,350 Our view of Jupiter before Juno was from the equator. 858 00:40:52,350 --> 00:40:56,620 So then when Juno flies over the poles and is looking down, 859 00:40:56,620 --> 00:41:00,970 and there we see these vortices, all this structure, 860 00:41:00,970 --> 00:41:02,780 it's just extraordinary. 861 00:41:02,780 --> 00:41:05,530 (dramatic music) 862 00:41:06,560 --> 00:41:10,870 The Juno cam that little camera that was just slapped on 863 00:41:10,870 --> 00:41:13,220 to get some publicity photos 864 00:41:13,220 --> 00:41:16,193 has turned out to be just extraordinary. 865 00:41:18,070 --> 00:41:19,970 I'd love to say that I figured this out 866 00:41:19,970 --> 00:41:20,900 and did it on purpose, 867 00:41:20,900 --> 00:41:23,570 but really what I wanted was a great picture. 868 00:41:23,570 --> 00:41:25,750 Little did we know that the poles of Jupiter 869 00:41:25,750 --> 00:41:29,340 were gonna become this huge science discover by itself. 870 00:41:29,340 --> 00:41:32,643 Giant polar cyclones nobody anticipated that. 871 00:41:34,210 --> 00:41:37,510 With the help of the citizen scientists around the world 872 00:41:37,510 --> 00:41:39,610 helping us process those images 873 00:41:39,610 --> 00:41:43,080 we are seeing all sorts of little structures, 874 00:41:43,080 --> 00:41:45,040 and pop up you clouds. 875 00:41:45,040 --> 00:41:47,835 Nobody expected that level of detail. 876 00:41:47,835 --> 00:41:50,440 (dramatic music) 877 00:41:50,440 --> 00:41:52,260 When we fly in close measuring 878 00:41:52,260 --> 00:41:54,830 the perturbations in Juno's motion, 879 00:41:54,830 --> 00:41:57,643 we're beginning to get a sense of what it's like inside. 880 00:41:59,270 --> 00:42:00,940 What we're finding is that 881 00:42:00,940 --> 00:42:02,840 it's not like the textbook picture 882 00:42:02,840 --> 00:42:06,680 where you have a metal rock core inside 883 00:42:06,680 --> 00:42:11,080 and then a layer of hydrogen, and then a layer of gas above. 884 00:42:11,080 --> 00:42:13,310 It's much fuzzier, much more mixed up, 885 00:42:13,310 --> 00:42:14,920 and so, in fact, that core 886 00:42:14,920 --> 00:42:17,960 is spread out to about 40% of the radius. 887 00:42:17,960 --> 00:42:20,603 It's mixed in with the metallic hydrogen. 888 00:42:21,770 --> 00:42:24,700 You're beginning to see that the convection system 889 00:42:24,700 --> 00:42:27,780 we see on the outside extend a long way in. 890 00:42:27,780 --> 00:42:29,811 They're much, much deeper. 891 00:42:29,811 --> 00:42:33,144 (gentle dramatic music) 892 00:42:34,530 --> 00:42:38,410 But what Juno has not yet been able to explain 893 00:42:38,410 --> 00:42:40,140 is what drives the jets? 894 00:42:40,140 --> 00:42:42,620 It might be that turbulence 895 00:42:42,620 --> 00:42:44,700 at the surface drives these jets, 896 00:42:44,700 --> 00:42:47,275 and then the jets burrow down into the depths. 897 00:42:47,275 --> 00:42:49,110 (dramatic music) 898 00:42:49,110 --> 00:42:51,180 But with Jupiter so much heat is coming 899 00:42:51,180 --> 00:42:52,690 out of the interior of the planet, 900 00:42:52,690 --> 00:42:55,960 that maybe the jets are being driven by deep motions, 901 00:42:55,960 --> 00:42:57,620 and it's their surface expression 902 00:42:57,620 --> 00:42:59,220 that we're seeing about the top. 903 00:43:00,550 --> 00:43:02,790 There's probably something deep down 904 00:43:02,790 --> 00:43:06,343 is driving a lot of motion inside of Jupiter. 905 00:43:07,240 --> 00:43:10,080 We're beginning to think about that region 906 00:43:10,080 --> 00:43:12,240 where hydrogen becomes metallic 907 00:43:12,240 --> 00:43:15,366 that generates this strong magnetic field. 908 00:43:15,366 --> 00:43:18,640 The magnetic field is probably moving things around. 909 00:43:18,640 --> 00:43:21,790 Driving convection and eddies and all kinds of motion, 910 00:43:21,790 --> 00:43:24,360 and so somewhere there's a balancing act. 911 00:43:24,360 --> 00:43:26,520 The stuff that's coming in from the top 912 00:43:26,520 --> 00:43:29,100 meets the stuff that's coming up from the bottom, 913 00:43:29,100 --> 00:43:31,023 and all hell breaks lose. 914 00:43:32,060 --> 00:43:33,030 What's the right answer? 915 00:43:33,030 --> 00:43:35,130 We do not yet know. 916 00:43:35,130 --> 00:43:36,720 Open question. 917 00:43:36,720 --> 00:43:39,430 One of the great questions for me 918 00:43:39,430 --> 00:43:42,823 as a scientist looking at Jupiter and studying Jupiter. 919 00:43:44,420 --> 00:43:47,090 Nobody really knows for sure what makes the colors 920 00:43:47,090 --> 00:43:49,060 in Jupiter's zones and belts. 921 00:43:49,060 --> 00:43:50,870 We see all these oranges and reds 922 00:43:50,870 --> 00:43:53,430 and beautiful yellows and browns. 923 00:43:53,430 --> 00:43:56,710 Io spewing out tons of sulfur among other things 924 00:43:56,710 --> 00:43:58,063 because it's volcanic. 925 00:43:59,210 --> 00:44:01,620 Models sort of indicate to us that 926 00:44:01,620 --> 00:44:04,590 as I radioactively change sulfur, 927 00:44:04,590 --> 00:44:06,630 it can make these reddish hues, 928 00:44:06,630 --> 00:44:09,970 and so Io may have had a huge effect 929 00:44:09,970 --> 00:44:12,400 on the way Jupiter appears to us. 930 00:44:12,400 --> 00:44:14,360 But it's producing a lot of material 931 00:44:14,360 --> 00:44:16,080 that's definitely going into Jupiter, 932 00:44:16,080 --> 00:44:17,800 and it may be part of the reason that Jupiter 933 00:44:17,800 --> 00:44:19,723 is this incredibly beautiful object. 934 00:44:21,380 --> 00:44:24,480 So in many ways the combination of Io 935 00:44:24,480 --> 00:44:28,030 and its volcanoes with Jupiter's strong magnetic field, 936 00:44:28,030 --> 00:44:32,044 is really at the core of an engine or a generator. 937 00:44:32,044 --> 00:44:37,044 (low rumbling) (dramatic music) 938 00:44:39,980 --> 00:44:42,180 (gentle music) 939 00:44:42,180 --> 00:44:44,420 When we laid out the objectives of Juno, 940 00:44:44,420 --> 00:44:46,620 it was to go sort of figure out the puzzles 941 00:44:46,620 --> 00:44:48,720 of what it was made out of and how it formed. 942 00:44:48,720 --> 00:44:51,097 Nobody really conceived of the idea that we'd go there, 943 00:44:51,097 --> 00:44:53,090 and the entire structure was gonna be 944 00:44:53,090 --> 00:44:54,752 different than we thought. 945 00:44:54,752 --> 00:44:57,250 (gentle music) 946 00:44:57,250 --> 00:45:00,500 It may be that we've been a bit naive. 947 00:45:00,500 --> 00:45:03,050 That if Jupiter could throw us this many curve balls, 948 00:45:03,050 --> 00:45:06,130 that our ideas of how stars worked 949 00:45:06,130 --> 00:45:07,650 could be kind of wrong too. 950 00:45:07,650 --> 00:45:09,140 I mean, there's even more energy, 951 00:45:09,140 --> 00:45:10,640 and they're even more massive. 952 00:45:12,760 --> 00:45:15,170 Astronomers have looked out and seen many stars, 953 00:45:15,170 --> 00:45:17,080 right, billions, and billions. 954 00:45:17,080 --> 00:45:19,690 Many of those are binary systems, 955 00:45:19,690 --> 00:45:21,990 two stars going around each other. 956 00:45:21,990 --> 00:45:24,870 Sometimes there's a big star and a little star. 957 00:45:24,870 --> 00:45:27,950 Maybe a star that has only a tiny bit of fusion inside 958 00:45:27,950 --> 00:45:29,050 like a brown dwarf. 959 00:45:29,050 --> 00:45:31,360 In our case and many others we've seen 960 00:45:31,360 --> 00:45:34,370 where we have a star and a planetary system, 961 00:45:34,370 --> 00:45:37,800 the biggest planet does not have enough mass 962 00:45:37,800 --> 00:45:40,370 to have a fusion reaction inside. 963 00:45:40,370 --> 00:45:42,210 So let's think of our solar system 964 00:45:42,210 --> 00:45:44,310 where we have the sun and we have Jupiter. 965 00:45:45,380 --> 00:45:49,620 Jupiter is 1/1000th the volume 966 00:45:49,620 --> 00:45:52,480 and 1/1000th the mass of the sun, 967 00:45:52,480 --> 00:45:56,040 and so it's too small to have fusion inside. 968 00:45:56,040 --> 00:45:58,350 It's a failed star. 969 00:45:58,350 --> 00:46:00,673 But it's a very successful planet. 970 00:46:02,002 --> 00:46:04,752 (dramatic music) 971 00:46:07,970 --> 00:46:10,310 Juno continues to explore Jupiter 972 00:46:11,180 --> 00:46:13,970 diving beneath the lethal radiation belt 973 00:46:13,970 --> 00:46:15,990 on every daring orbit, 974 00:46:15,990 --> 00:46:19,100 and each time we learn a little more about 975 00:46:19,100 --> 00:46:21,473 the greatest planet in the solar system. 976 00:46:23,270 --> 00:46:27,403 But we have unfinished business with some of its moons. 977 00:46:29,040 --> 00:46:32,170 JUICE is the next major exploration mission 978 00:46:32,170 --> 00:46:33,693 for the European space agency. 979 00:46:34,750 --> 00:46:37,223 Jupiter, icy moons, explorer. 980 00:46:38,400 --> 00:46:40,290 Its sole purpose is to go to Jupiter 981 00:46:40,290 --> 00:46:42,023 and explore the icy moons. 982 00:46:44,310 --> 00:46:46,330 The main aim is really to try and understand 983 00:46:46,330 --> 00:46:48,380 what they look like below the surface, 984 00:46:48,380 --> 00:46:50,610 how thick is the ice layer, 985 00:46:50,610 --> 00:46:53,270 how deep is the subsurface ocean. 986 00:46:53,270 --> 00:46:56,440 NASA has been funding a mission called Europa Clipper, 987 00:46:56,440 --> 00:46:59,600 which will take a number of flybys of Europa 988 00:46:59,600 --> 00:47:01,730 to try and get a deeper investigation 989 00:47:01,730 --> 00:47:03,410 of what might be happening on the surface, 990 00:47:03,410 --> 00:47:05,100 even a basic understanding of some 991 00:47:05,100 --> 00:47:06,750 of the chemistry that might be there, 992 00:47:06,750 --> 00:47:09,300 in preparation for investigations yet to come 993 00:47:09,300 --> 00:47:10,630 getting down to the oceans. 994 00:47:10,630 --> 00:47:12,630 For places like Europa, Ganymede, 995 00:47:12,630 --> 00:47:15,850 getting below the ice layer is the holy grail. 996 00:47:15,850 --> 00:47:18,290 Getting into that subsurface ocean 997 00:47:18,290 --> 00:47:19,460 that is a whole new frontier, 998 00:47:19,460 --> 00:47:21,250 and that will be a fascinating thing 999 00:47:21,250 --> 00:47:23,157 if we can ever achieve that. 1000 00:47:23,157 --> 00:47:24,740 Well, the first challenge you have 1001 00:47:24,740 --> 00:47:27,340 is actually getting down through the ice. 1002 00:47:27,340 --> 00:47:30,480 While people have talked about drills and other such things, 1003 00:47:30,480 --> 00:47:32,510 we wanna reduce this 20-kilometers of ice 1004 00:47:32,510 --> 00:47:34,050 as much as possible, 1005 00:47:34,050 --> 00:47:36,280 and so we've built submersibles 1006 00:47:36,280 --> 00:47:39,810 that can actually navigate through tunnels and canyons 1007 00:47:39,810 --> 00:47:42,170 to be able to try and make their way down through perhaps 1008 00:47:42,170 --> 00:47:45,000 these open crevices as close to the water as possible. 1009 00:47:45,000 --> 00:47:47,200 Now if we can get into the water itself, 1010 00:47:47,200 --> 00:47:50,200 we've built a buoyant rover that goes underneath the ice 1011 00:47:50,200 --> 00:47:53,330 and floats so it drives on the underside of the ice 1012 00:47:53,330 --> 00:47:56,000 exactly at that ice water boundary on there 1013 00:47:56,000 --> 00:47:58,760 by turning the camera to look up at the microbes 1014 00:47:58,760 --> 00:48:01,380 that we might find there on the underside of the ice. 1015 00:48:01,380 --> 00:48:03,880 Then we've been working on deep ocean vessels 1016 00:48:03,880 --> 00:48:05,560 where we hope to go down to the bottom 1017 00:48:05,560 --> 00:48:07,210 of the ocean on Europa, 1018 00:48:07,210 --> 00:48:09,470 and then bring back samples to us 1019 00:48:09,470 --> 00:48:12,600 of what might be down at the bottom of the ocean. 1020 00:48:12,600 --> 00:48:15,550 JUICE doesn't launch till 2022. 1021 00:48:15,550 --> 00:48:18,860 It's not gonna get there until 2030. 1022 00:48:18,860 --> 00:48:21,970 In the mid-2020s we hope to launch Europa Clipper. 1023 00:48:21,970 --> 00:48:26,281 After a 67-year voyage we'll reach Jupiter itself. 1024 00:48:26,281 --> 00:48:27,580 (dramatic music) 1025 00:48:27,580 --> 00:48:29,850 Some of the people already working on it now 1026 00:48:29,850 --> 00:48:31,180 will have retired. 1027 00:48:31,180 --> 00:48:33,010 Some will probably have passed away. 1028 00:48:33,010 --> 00:48:34,750 What I love about it is that there's this 1029 00:48:34,750 --> 00:48:36,810 generational feeling to it. 1030 00:48:36,810 --> 00:48:38,550 By the time we get the data, 1031 00:48:38,550 --> 00:48:40,190 there will be another generation 1032 00:48:40,190 --> 00:48:41,720 of scientists looking at it. 1033 00:48:41,720 --> 00:48:44,290 There is an immense opportunity 1034 00:48:44,290 --> 00:48:46,880 for us to find the first signs of life 1035 00:48:46,880 --> 00:48:50,860 beyond our world in these warm, watery, 1036 00:48:50,860 --> 00:48:54,200 rich environments that we are just beginning 1037 00:48:54,200 --> 00:48:56,023 to see that we can even access. 1038 00:48:56,980 --> 00:48:58,060 The rovers that we're developing 1039 00:48:58,060 --> 00:48:59,670 and that are testing here on Earth 1040 00:48:59,670 --> 00:49:02,950 are only the ancestors, the far ancestors, 1041 00:49:02,950 --> 00:49:05,431 of what we might eventually send there. 1042 00:49:05,431 --> 00:49:06,860 (dramatic music) 1043 00:49:06,860 --> 00:49:09,730 So, perhaps one day we'll discover life 1044 00:49:09,730 --> 00:49:11,760 residing under the ice, 1045 00:49:11,760 --> 00:49:14,630 a precious habitat thriving despite 1046 00:49:14,630 --> 00:49:17,230 the brutal radioactive environment 1047 00:49:17,230 --> 00:49:19,690 in the shadow of the mightiest planet 1048 00:49:19,690 --> 00:49:22,083 in our solar system: Jupiter. 1049 00:49:27,319 --> 00:49:30,069 (dramatic music)