1 00:00:00,053 --> 00:00:01,893 (bright music) 2 00:00:01,893 --> 00:00:04,450 I've always been really fascinated by Venus. 3 00:00:04,450 --> 00:00:07,730 because it's kind of an alternate Earth. 4 00:00:07,730 --> 00:00:09,540 Some people consider Venus 5 00:00:09,540 --> 00:00:11,290 to be a sister planet to the Earth. 6 00:00:11,290 --> 00:00:14,100 or perhaps a twin, but if it is, 7 00:00:14,100 --> 00:00:15,870 it's really an evil twin. 8 00:00:15,870 --> 00:00:17,100 I don't think it's evil, 9 00:00:17,100 --> 00:00:20,083 but it's a remarkably different twin. 10 00:00:21,040 --> 00:00:23,640 Earth's nearest planetary neighbor 11 00:00:23,640 --> 00:00:25,180 is an enigma. 12 00:00:25,180 --> 00:00:28,190 Venus has these incredibly thick clouds 13 00:00:28,190 --> 00:00:30,450 that you can't really see through. 14 00:00:30,450 --> 00:00:33,560 This is what makes it shine like a beacon in the sky. 15 00:00:33,560 --> 00:00:35,860 Actually, sometimes people think it's a UFO 16 00:00:35,860 --> 00:00:37,623 because it's so bright in the sky. 17 00:00:38,690 --> 00:00:40,740 Humans have looked at Venus 18 00:00:40,740 --> 00:00:43,323 and been drawn to it for millennia. 19 00:00:44,830 --> 00:00:47,760 To me, it's very haunting, very rich with lessons, 20 00:00:47,760 --> 00:00:51,200 and creates this desire to really understand that planet. 21 00:00:51,200 --> 00:00:53,930 But to begin to understand Venus, 22 00:00:53,930 --> 00:00:55,589 we have to go there. 23 00:00:55,589 --> 00:00:56,580 (dramatic music) 24 00:00:56,580 --> 00:00:57,990 It's definitely mysterious, 25 00:00:57,990 --> 00:00:59,857 and it's, of course, important for science. 26 00:00:59,857 --> 00:01:01,280 (people chatting) 27 00:01:01,280 --> 00:01:05,030 But it became clear that Venus is a little bit easier 28 00:01:05,030 --> 00:01:08,118 for the Soviet Union to explore for propaganda success. 29 00:01:08,118 --> 00:01:09,940 (man speaks in foreign language) 30 00:01:09,940 --> 00:01:11,890 And understanding Venus, 31 00:01:11,890 --> 00:01:14,603 could be key to our very survival. 32 00:01:15,590 --> 00:01:17,420 It's about the same radius as Earth. 33 00:01:17,420 --> 00:01:19,520 It was formed, more or less, the same place 34 00:01:19,520 --> 00:01:21,093 in the solar system than Earth. 35 00:01:21,930 --> 00:01:23,630 Perhaps our evolution is going 36 00:01:23,630 --> 00:01:26,380 to look like Venus in the future. 37 00:01:26,380 --> 00:01:28,300 We can't claim to understand Earth really 38 00:01:28,300 --> 00:01:29,961 if we don't understand Venus. 39 00:01:29,961 --> 00:01:33,544 (bright theatrical music) 40 00:01:40,855 --> 00:01:43,438 (gentle music) 41 00:01:48,099 --> 00:01:50,370 For centuries people wondered if this 42 00:01:50,370 --> 00:01:52,693 was what the surface of Venus looked like. 43 00:01:55,300 --> 00:01:56,950 Once we realized that the other planets 44 00:01:56,950 --> 00:01:59,590 were, in fact, planets, the natural assumption 45 00:01:59,590 --> 00:02:01,539 was that, well, they're probably similar, 46 00:02:01,539 --> 00:02:04,670 (gentle music) 47 00:02:04,670 --> 00:02:07,140 Venus was one of the first objects 48 00:02:07,140 --> 00:02:09,763 of scientific exploration for Russian science. 49 00:02:10,830 --> 00:02:14,270 Lomonosov, who is kind of father of Russian science, 50 00:02:14,270 --> 00:02:16,290 was the first astronomer 51 00:02:16,290 --> 00:02:19,240 who actually studied the atmosphere of Venus. 52 00:02:19,240 --> 00:02:21,370 We figured out the reason why Venus is so bright, 53 00:02:21,370 --> 00:02:22,550 and, apparently, featureless, 54 00:02:22,550 --> 00:02:24,850 is because it's completely covered in clouds. 55 00:02:24,850 --> 00:02:27,290 Naturally, we assume these are clouds of water 56 00:02:27,290 --> 00:02:29,750 like on the Earth, in which case, 57 00:02:29,750 --> 00:02:32,460 Venus would be a great swampy paradise, 58 00:02:32,460 --> 00:02:33,727 lots of water on the surface, 59 00:02:33,727 --> 00:02:35,490 and water in the atmosphere, 60 00:02:35,490 --> 00:02:37,600 totally covered by clouds. 61 00:02:37,600 --> 00:02:39,810 People imagine great lizards 62 00:02:39,810 --> 00:02:42,840 and dinosaurs living and swimming in the lakes 63 00:02:42,840 --> 00:02:46,047 and oceans the tropical forests of Venus. 64 00:02:46,047 --> 00:02:48,610 (dramatic music) 65 00:02:48,610 --> 00:02:52,610 Svante Arrhenius who was a brilliant Swedish chemist, 66 00:02:52,610 --> 00:02:55,280 was one of the first people to actually model 67 00:02:55,280 --> 00:02:57,880 scientifically what the climate of Venus was like. 68 00:02:57,880 --> 00:03:01,477 But he also had ideas about the life on Venus 69 00:03:01,477 --> 00:03:02,890 and the vegetation. 70 00:03:02,890 --> 00:03:05,850 He made observations that he thought confirmed this, 71 00:03:05,850 --> 00:03:09,340 so he actually had a kind of scientific view, 72 00:03:09,340 --> 00:03:12,390 but with a lot of imagination filling in the blanks 73 00:03:12,390 --> 00:03:14,170 that promoted this idea of Venus 74 00:03:14,170 --> 00:03:16,420 as a planet with a lot of vegetation 75 00:03:16,420 --> 00:03:18,650 and a lot of life that was similar to Earth. 76 00:03:18,650 --> 00:03:21,560 But maybe also Earth sort of stuck in the past, 77 00:03:21,560 --> 00:03:24,507 in an earlier age when Earth was sort of a swamp planet. 78 00:03:24,507 --> 00:03:25,660 (dramatic music) 79 00:03:25,660 --> 00:03:28,060 (birds chirping) 80 00:03:28,060 --> 00:03:30,360 The only way to tell actually whether Venus was 81 00:03:30,360 --> 00:03:33,330 a sort of living world with jungles on the surface 82 00:03:33,330 --> 00:03:35,343 was to actually go there with spacecraft. 83 00:03:35,343 --> 00:03:36,619 (dramatic music) 84 00:03:36,619 --> 00:03:39,230 (thunder roaring) 85 00:03:39,230 --> 00:03:41,370 But before 1975, 86 00:03:41,370 --> 00:03:43,370 no human had ever seen an image 87 00:03:43,370 --> 00:03:46,993 from the surface of another planet, let alone Venus. 88 00:03:47,840 --> 00:03:52,623 However, a Russian mission called Venera 9 was on its way. 89 00:03:55,160 --> 00:03:57,690 On 20th of October of 1975, 90 00:03:57,690 --> 00:03:59,730 this joint stock of spacecraft, 91 00:03:59,730 --> 00:04:02,410 of Lander and the Orbiter approached Venus 92 00:04:02,410 --> 00:04:03,993 and separated from each other. 93 00:04:04,860 --> 00:04:07,060 Immediately they started their separate missions, 94 00:04:07,060 --> 00:04:09,403 which were culminating at the same time. 95 00:04:10,600 --> 00:04:12,220 The Orbiter approached Venus 96 00:04:12,220 --> 00:04:14,240 and started a breaking maneuver 97 00:04:14,240 --> 00:04:16,910 with its entrance to slow down at speeds just enough 98 00:04:16,910 --> 00:04:19,840 that the gravity field of Venus would capture it 99 00:04:19,840 --> 00:04:23,100 and leave it in a highly-stretched elliptical orbit 100 00:04:23,100 --> 00:04:24,570 around the planet. 101 00:04:24,570 --> 00:04:27,880 This components of the Venera 9 spacecraft 102 00:04:27,880 --> 00:04:30,450 had become the first manmade object 103 00:04:30,450 --> 00:04:32,515 to enter orbit around Venus. 104 00:04:32,515 --> 00:04:34,600 (bright theatrical music) 105 00:04:34,600 --> 00:04:37,040 But the mission was far from over. 106 00:04:37,040 --> 00:04:38,370 And at the same time, 107 00:04:38,370 --> 00:04:41,670 the Lander started going into the atmosphere 108 00:04:41,670 --> 00:04:43,620 of Venus on the side of the planet, 109 00:04:43,620 --> 00:04:45,570 which was not visible from Earth, 110 00:04:45,570 --> 00:04:47,310 but sensed to the Orbiter, 111 00:04:47,310 --> 00:04:49,630 which was so high in the sky over Venus, 112 00:04:49,630 --> 00:04:53,620 it would later act as a lay station for the Lander 113 00:04:53,620 --> 00:04:56,893 to send pictures back to mission control on Earth. 114 00:04:57,740 --> 00:05:00,280 The Lander was a bowl-shaped capsule 115 00:05:00,280 --> 00:05:03,360 covered with a special ablative surface, 116 00:05:03,360 --> 00:05:06,080 and once it entered the atmosphere of Venus 117 00:05:06,080 --> 00:05:09,340 and started breaking, layer by layer, 118 00:05:09,340 --> 00:05:10,880 burning ablative surface, 119 00:05:10,880 --> 00:05:13,430 and at the same time slowing down 120 00:05:13,430 --> 00:05:16,240 tremendously from its initial entry speed. 121 00:05:16,240 --> 00:05:19,230 The searing heat shield decelerated the Lander 122 00:05:19,230 --> 00:05:22,020 from 10.7 kilometers per second 123 00:05:22,020 --> 00:05:25,005 to around 250 meters per second. 124 00:05:25,005 --> 00:05:26,820 (bright theatrical music) 125 00:05:26,820 --> 00:05:28,670 Then once it's slowed down enough, 126 00:05:28,670 --> 00:05:31,170 it was safe enough to open small opening 127 00:05:31,170 --> 00:05:32,580 at the top of the capsule 128 00:05:32,580 --> 00:05:35,120 and release two small breaking parachutes. 129 00:05:35,120 --> 00:05:37,280 One of those two parachutes was then used 130 00:05:37,280 --> 00:05:40,120 to release the top part of the capsule 131 00:05:40,120 --> 00:05:42,040 and reveal the top of the Lander, 132 00:05:42,040 --> 00:05:44,053 which was inside of that cocoon. 133 00:05:44,053 --> 00:05:47,553 (bright theatrical music) 134 00:05:49,260 --> 00:05:52,670 The speed dropped from 250 meters per second 135 00:05:52,670 --> 00:05:54,740 to 150 meters per second 136 00:05:55,810 --> 00:05:57,893 before a third parachute was deployed. 137 00:06:00,000 --> 00:06:02,640 And once that happened, there was an antenna, 138 00:06:02,640 --> 00:06:04,710 a transmission antenna exposed, 139 00:06:04,710 --> 00:06:07,100 and that allowed it to immediately start transmitting 140 00:06:07,100 --> 00:06:09,840 data to the Orbiter, which in turn, 141 00:06:09,840 --> 00:06:11,603 relayed back to the ground control. 142 00:06:12,730 --> 00:06:14,750 The third parachute brought the velocity 143 00:06:14,750 --> 00:06:17,943 of the Lander down to just 50 meters per second. 144 00:06:18,910 --> 00:06:21,580 And then that parachute was separated, 145 00:06:21,580 --> 00:06:24,720 and it pulls out three canopy main parachute system, 146 00:06:24,720 --> 00:06:28,023 which allows the Lander really slow and gentle descent. 147 00:06:29,020 --> 00:06:32,090 After all the drama of it's journey so far, 148 00:06:32,090 --> 00:06:34,800 the Lander would then spend 20 minutes 149 00:06:34,800 --> 00:06:38,220 calmly taking measurements of the atmosphere, 150 00:06:38,220 --> 00:06:41,223 but its brutal voyage was not over yet. 151 00:06:42,750 --> 00:06:46,530 When the probe is around 50 kilometers over the surface, 152 00:06:46,530 --> 00:06:49,480 the command is sent to cut the main lines of the parachute. 153 00:06:53,162 --> 00:06:56,040 (gentle dramatic music) 154 00:06:56,040 --> 00:06:59,300 Venus has always been a special object of fascination 155 00:06:59,300 --> 00:07:01,040 as long as we've been observing the sky, 156 00:07:01,040 --> 00:07:04,780 which is probably longer than we've been people, 157 00:07:04,780 --> 00:07:05,790 and there's a reason for that. 158 00:07:05,790 --> 00:07:07,490 It's so bright. 159 00:07:07,490 --> 00:07:09,150 It's the brightest object 160 00:07:09,150 --> 00:07:11,193 other than the full moon at night. 161 00:07:12,150 --> 00:07:13,860 For much of human history, 162 00:07:13,860 --> 00:07:18,860 we've mistaken Venus for a star or two stars to be precise, 163 00:07:19,090 --> 00:07:22,120 the morning star and the evening star. 164 00:07:22,120 --> 00:07:23,960 It appears as an evening star 165 00:07:23,960 --> 00:07:25,470 for a little while near the horizon 166 00:07:25,470 --> 00:07:28,010 and then disappears and then reappears 167 00:07:28,010 --> 00:07:30,550 as a morning star near the horizon. 168 00:07:30,550 --> 00:07:32,600 Does this intricate little dance in the sky 169 00:07:32,600 --> 00:07:34,210 and then disappears again. 170 00:07:34,210 --> 00:07:37,000 So it bounces from evening to morning. 171 00:07:37,000 --> 00:07:38,640 It's never up in the middle of the night. 172 00:07:38,640 --> 00:07:40,640 It's always at the dusk and dawn, 173 00:07:40,640 --> 00:07:43,350 which are the most evocative times. 174 00:07:43,350 --> 00:07:46,270 That has led it to be an object of mythology, 175 00:07:46,270 --> 00:07:49,083 and folklore, and with gods and goddesses. 176 00:07:50,230 --> 00:07:52,540 The association of Venus with femininity 177 00:07:52,540 --> 00:07:54,200 really comes out of the fact 178 00:07:54,200 --> 00:07:56,440 that we're still very dominated 179 00:07:56,440 --> 00:08:00,880 by Greek and Roman Western traditions. 180 00:08:00,880 --> 00:08:03,280 But, in fact, that's just one tradition, 181 00:08:03,280 --> 00:08:05,040 and if you look around the world, 182 00:08:05,040 --> 00:08:07,410 for instance, the Meso Americans 183 00:08:07,410 --> 00:08:09,830 who were probably the greatest Venus observers 184 00:08:09,830 --> 00:08:11,180 in terms of what they figured out 185 00:08:11,180 --> 00:08:13,320 about how to predict the motions and everything, 186 00:08:13,320 --> 00:08:14,720 for those civilizations, 187 00:08:14,720 --> 00:08:18,400 Venus was this macho warrior dude, 188 00:08:18,400 --> 00:08:20,620 and it was very much a male character. 189 00:08:20,620 --> 00:08:24,740 So why assign a gender to a planet? 190 00:08:24,740 --> 00:08:26,990 Planet's are at least as complex as people. 191 00:08:26,990 --> 00:08:30,640 So, I think, it maybe does do it a bit of a disservice 192 00:08:30,640 --> 00:08:32,992 just to say Venus is the female planet. 193 00:08:32,992 --> 00:08:35,575 (gentle music) 194 00:08:36,980 --> 00:08:38,530 After the II World War, 195 00:08:38,530 --> 00:08:42,350 it wasn't long before the Soviet Union stunned the world 196 00:08:42,350 --> 00:08:45,323 with the launch of Sputnik in 1957. 197 00:08:46,270 --> 00:08:50,470 A year later the U.S. launched its first spacecraft. 198 00:08:50,470 --> 00:08:52,123 The space race had begun. 199 00:08:53,965 --> 00:08:55,370 (dramatic music) 200 00:08:55,370 --> 00:08:58,650 The space race was driven by several major factors. 201 00:08:58,650 --> 00:09:00,500 First of all, it was a military competition 202 00:09:00,500 --> 00:09:03,330 of two superpowers which emerged after World War II, 203 00:09:03,330 --> 00:09:05,313 the United States and the Soviet Union, 204 00:09:06,170 --> 00:09:09,870 and the second is this ideological competition 205 00:09:09,870 --> 00:09:12,900 between two systems, socialism in the Soviet Union, 206 00:09:12,900 --> 00:09:15,733 and capitalism, as at least Soviet Union saw it. 207 00:09:16,650 --> 00:09:19,663 That competition included scientific pursuit. 208 00:09:20,530 --> 00:09:22,350 In the world of science probably the best way 209 00:09:22,350 --> 00:09:26,580 to prove that superiority would be with victories in space, 210 00:09:26,580 --> 00:09:29,360 and the Soviet government understood this. 211 00:09:29,360 --> 00:09:31,910 Space exploration has a dark side. 212 00:09:31,910 --> 00:09:35,480 We can't deny that we rode to the moon 213 00:09:35,480 --> 00:09:38,270 and to the other planets on the wings of war. 214 00:09:38,270 --> 00:09:40,670 That the reason we have these rockets 215 00:09:40,670 --> 00:09:44,620 that can launch payloads into orbit and beyond 216 00:09:44,620 --> 00:09:48,521 is because they were developed to destroy cities. 217 00:09:48,521 --> 00:09:49,830 (bomb explodes) 218 00:09:49,830 --> 00:09:53,370 The emergence of rocket technology immediately gives 219 00:09:53,370 --> 00:09:55,540 scientists this idea that you can put 220 00:09:55,540 --> 00:09:57,530 scientific instruments on the rocket 221 00:09:57,530 --> 00:10:00,190 and fly them first to the upper atmospheres, then to space, 222 00:10:00,190 --> 00:10:03,310 and then into deep space all across the solar system. 223 00:10:03,310 --> 00:10:04,610 But within the Soviet Union, 224 00:10:04,610 --> 00:10:06,530 it was in the framework of testing 225 00:10:06,530 --> 00:10:09,600 intercontinental ballistic missiles and weapons systems. 226 00:10:09,600 --> 00:10:12,380 It was absolutely under the same level of secrecy. 227 00:10:12,380 --> 00:10:13,890 There was absolutely no public. 228 00:10:13,890 --> 00:10:16,010 This was absolutely top secret. 229 00:10:16,010 --> 00:10:17,960 We didn't use the term spacecraft in those days. 230 00:10:17,960 --> 00:10:19,580 We called the payloads because 231 00:10:19,580 --> 00:10:21,550 everything went on top of a launch vehicle. 232 00:10:21,550 --> 00:10:23,417 Main thing you put on top of the launch vehicle 233 00:10:23,417 --> 00:10:25,673 was the warhead, which was the payload. 234 00:10:26,650 --> 00:10:28,550 The idea was we're really 235 00:10:28,550 --> 00:10:30,100 trying to develop a launch vehicle. 236 00:10:30,100 --> 00:10:32,340 The payload was sort of insignificant addition 237 00:10:32,340 --> 00:10:33,443 back in those days. 238 00:10:34,500 --> 00:10:35,570 What happened early on in 239 00:10:35,570 --> 00:10:37,727 the space race is we began to say, 240 00:10:37,727 --> 00:10:40,380 "Hey, the solar system let's explore it," 241 00:10:40,380 --> 00:10:43,360 and our competitors, the former Soviet Union, 242 00:10:43,360 --> 00:10:44,400 was doing the same thing. 243 00:10:44,400 --> 00:10:47,800 Now they happened to have set their sights on Venus 244 00:10:47,800 --> 00:10:49,468 really, really hard. 245 00:10:49,468 --> 00:10:51,540 (dramatic music) 246 00:10:51,540 --> 00:10:53,420 The initial motivation for the 247 00:10:53,420 --> 00:10:56,820 Soviet space program was propaganda success. 248 00:10:56,820 --> 00:11:00,750 The ideas about Venus as a tropical paradise 249 00:11:00,750 --> 00:11:03,540 were not at play in a process of decision 250 00:11:03,540 --> 00:11:05,350 to fly spacecraft to Venus. 251 00:11:05,350 --> 00:11:06,760 Its definitely mysterious, 252 00:11:06,760 --> 00:11:08,850 and it's, of course, important for science. 253 00:11:08,850 --> 00:11:10,780 But the most important factor was 254 00:11:10,780 --> 00:11:13,390 that it's easier to reach than Mars. 255 00:11:13,390 --> 00:11:15,990 The rocket scientists in the early space race 256 00:11:15,990 --> 00:11:19,730 concluded that in order to get to Venus there's a window 257 00:11:19,730 --> 00:11:23,050 of time in which the planets are closest. 258 00:11:23,050 --> 00:11:26,450 This occurs every 19 months. 259 00:11:26,450 --> 00:11:30,530 From the moment the race to Venus began in 1961, 260 00:11:30,530 --> 00:11:34,723 only three opportunities were missed until 1986. 261 00:11:35,710 --> 00:11:38,250 First off the mark was the Soviets' 262 00:11:38,250 --> 00:11:42,090 Tyazhely Sputnik in February 1961. 263 00:11:42,090 --> 00:11:44,413 It failed to leave low-Earth orbit. 264 00:11:46,010 --> 00:11:50,343 Venera 1 became the first spacecraft to fly past Venus. 265 00:11:51,926 --> 00:11:56,497 But due to a communications failure, no data were received. 266 00:11:56,497 --> 00:11:57,400 (dramatic music) 267 00:11:57,400 --> 00:12:00,160 The early history of trying to get to Venus 268 00:12:00,160 --> 00:12:01,400 is full of failure. 269 00:12:01,400 --> 00:12:04,130 There were a lot more failures than successes. 270 00:12:04,130 --> 00:12:06,710 Within weeks of the first two attempts 271 00:12:06,710 --> 00:12:08,780 to send a spacecraft to Venus, 272 00:12:08,780 --> 00:12:12,380 a discovery from an Earth-based radio telescope 273 00:12:12,380 --> 00:12:15,730 increased the intrigue about our mysterious twin. 274 00:12:15,730 --> 00:12:16,880 (dramatic music) 275 00:12:16,880 --> 00:12:20,810 Venus was found to have a very odd rotation. 276 00:12:20,810 --> 00:12:25,300 The planets seemed to be rotating backwards very slowly. 277 00:12:25,300 --> 00:12:29,500 A day on Venus is longer than its year. 278 00:12:29,500 --> 00:12:32,350 You could say why does Venus rotate backwards? 279 00:12:32,350 --> 00:12:33,720 But you can also say why do all 280 00:12:33,720 --> 00:12:35,570 the other planets rotate forwards? 281 00:12:35,570 --> 00:12:36,560 I mean, it's a mystery. 282 00:12:36,560 --> 00:12:39,030 We don't really understand Venus' rotation rate, 283 00:12:39,030 --> 00:12:40,800 but we don't really understand the rotation rates 284 00:12:40,800 --> 00:12:42,281 of the planets in general. 285 00:12:42,281 --> 00:12:43,630 (dramatic music) 286 00:12:43,630 --> 00:12:45,430 Eighteen months after the discovery 287 00:12:45,430 --> 00:12:47,860 of Venus' peculiar rotation, 288 00:12:47,860 --> 00:12:51,163 the next opportunity to get to Venus was approaching. 289 00:12:52,153 --> 00:12:53,500 (gentle dramatic music) 290 00:12:53,500 --> 00:12:56,420 In the second half of summer of 1962, 291 00:12:56,420 --> 00:12:58,890 all these forces finally came together. 292 00:12:58,890 --> 00:13:01,780 Both sides finally had the rockets necessary to launch. 293 00:13:01,780 --> 00:13:03,350 They had the spacecraft, 294 00:13:03,350 --> 00:13:06,067 which was sophisticated enough to go to Venus, 295 00:13:06,067 --> 00:13:08,220 and they had this motivation, money, 296 00:13:08,220 --> 00:13:10,860 and all the political rationale to do this. 297 00:13:10,860 --> 00:13:13,290 So within this short period of time, 298 00:13:13,290 --> 00:13:15,690 from July to beginning of September, 299 00:13:15,690 --> 00:13:18,630 there were five missions launched, two Mariner probes 300 00:13:18,630 --> 00:13:21,623 and three Russian MV probes as they were called. 301 00:13:22,780 --> 00:13:25,210 Mariners 1 and 2 were identical, 302 00:13:25,210 --> 00:13:27,500 and they were both modified Ranger spacecraft 303 00:13:27,500 --> 00:13:29,330 taken off the product line 304 00:13:29,330 --> 00:13:32,410 and converted for a mission to Venus 305 00:13:32,410 --> 00:13:35,431 rather than a Ranger mission to the moon. 306 00:13:35,431 --> 00:13:36,860 (gentle dramatic music) 307 00:13:36,860 --> 00:13:38,730 They were hexagonal in the shape 308 00:13:38,730 --> 00:13:41,230 about six boxes bolted onto a frame. 309 00:13:41,230 --> 00:13:43,200 There was a high-gain antenna, 310 00:13:43,200 --> 00:13:44,690 and there was a tower structure 311 00:13:44,690 --> 00:13:46,750 bolted on top of this hexagonal. 312 00:13:46,750 --> 00:13:47,993 We called it a bus. 313 00:13:49,100 --> 00:13:53,810 It wasn't at all unusual to be working 56 hours a week, 314 00:13:53,810 --> 00:13:56,000 and if that meant everybody had to work weekends 315 00:13:56,000 --> 00:13:59,810 or something like that or 16-hour days, 316 00:13:59,810 --> 00:14:02,150 we did it for the time that it took 317 00:14:02,150 --> 00:14:03,939 to get back on that schedule. 318 00:14:03,939 --> 00:14:05,140 (dramatic music) 319 00:14:05,140 --> 00:14:08,290 On the 22nd of July 1962, 320 00:14:08,290 --> 00:14:10,400 Mariner 1 launched, 321 00:14:10,400 --> 00:14:12,730 buts the spacecraft malfunctioned, 322 00:14:12,730 --> 00:14:15,653 and flight control had to manually destroy it. 323 00:14:16,650 --> 00:14:20,329 A month later, the first Soviet spacecraft called 324 00:14:20,329 --> 00:14:25,310 2MV-1 Number One succeeded in getting into orbit. 325 00:14:25,310 --> 00:14:27,910 But it's upper stage rocket booster failed, 326 00:14:27,910 --> 00:14:30,556 and it never left low Earth orbit. 327 00:14:30,556 --> 00:14:32,490 (dramatic music) 328 00:14:32,490 --> 00:14:35,140 Two days later, Mariner 2 329 00:14:35,140 --> 00:14:38,116 blasted off successfully from Cape Canaveral, 330 00:14:38,116 --> 00:14:39,520 (dramatic music) 331 00:14:39,520 --> 00:14:42,670 followed by the final two Soviet spacecraft 332 00:14:42,670 --> 00:14:45,193 on the 1st and 12th of September. 333 00:14:46,220 --> 00:14:49,253 Both failed to leave Earth's orbit. 334 00:14:49,253 --> 00:14:50,580 (dramatic music) 335 00:14:50,580 --> 00:14:54,934 Three months later on the 14th of December 1962, 336 00:14:54,934 --> 00:14:58,170 (bright music) 337 00:14:58,170 --> 00:15:01,053 Mariner 2 arrived safely at Venus. 338 00:15:04,119 --> 00:15:06,410 Mariner 2 became the first spacecraft 339 00:15:06,410 --> 00:15:09,210 to explore another planet in the solar system 340 00:15:09,210 --> 00:15:12,150 and actually return useful scientific data 341 00:15:12,150 --> 00:15:14,122 from the vicinity of another planet. 342 00:15:14,122 --> 00:15:16,705 (bright music) 343 00:15:20,670 --> 00:15:21,840 (gentle music) 344 00:15:21,840 --> 00:15:24,170 The measurement that Mariner 2 made 345 00:15:24,170 --> 00:15:28,430 suggested that the upper atmosphere of Venus was very hot 346 00:15:28,430 --> 00:15:32,030 in the region of 500 degrees celsius. 347 00:15:32,030 --> 00:15:33,810 Perhaps Venus wasn't quite 348 00:15:33,810 --> 00:15:36,167 the paradise everyone had hoped for. 349 00:15:37,860 --> 00:15:40,040 There was an editorial in the New York Times 350 00:15:40,040 --> 00:15:43,530 when the Mariner 2 results were reported, 351 00:15:43,530 --> 00:15:46,387 and it was titled "Venus Says No", 352 00:15:47,460 --> 00:15:51,230 and it talks about the grand romantic dreams 353 00:15:51,230 --> 00:15:53,563 of mankind being dashed. 354 00:15:56,330 --> 00:15:57,840 Mariner 2 also made 355 00:15:57,840 --> 00:16:00,220 another startling discovery. 356 00:16:00,220 --> 00:16:03,623 It could be a hint that all was not well with Earth's twin. 357 00:16:04,850 --> 00:16:06,200 Unlike our planet, 358 00:16:06,200 --> 00:16:08,830 with its North and South magnetic poles, 359 00:16:08,830 --> 00:16:12,043 Venus doesn't have any significant magnetic field. 360 00:16:13,980 --> 00:16:16,010 It's about the same radius as Earth. 361 00:16:16,010 --> 00:16:18,720 It's roughly the same rotation, right? 362 00:16:18,720 --> 00:16:21,870 Maybe it's a hundred times slower, 363 00:16:21,870 --> 00:16:24,790 but that's not that different, fluid dynamics wise. 364 00:16:24,790 --> 00:16:26,870 These are still rapidly rotating bodies. 365 00:16:26,870 --> 00:16:28,500 It's got a big core we believe. 366 00:16:28,500 --> 00:16:29,810 We believe it's molten. 367 00:16:29,810 --> 00:16:32,513 Something's funny that Venus has no dynamo. 368 00:16:34,290 --> 00:16:38,287 Mariner 2 took measurements of high temperatures on Venus, 369 00:16:38,287 --> 00:16:41,420 and there was a dispute about those temperatures, 370 00:16:41,420 --> 00:16:43,830 perhaps being only high in the atmosphere 371 00:16:43,830 --> 00:16:46,710 or the temperatures really showing an unbearably 372 00:16:46,710 --> 00:16:50,560 hot environment everywhere around the planet. 373 00:16:50,560 --> 00:16:53,390 So, of course, the immediate challenge was after this, 374 00:16:53,390 --> 00:16:56,290 both for the Soviet Union and for the American scientists 375 00:16:56,290 --> 00:16:59,210 was to launch more probes, more sophisticated ones, 376 00:16:59,210 --> 00:17:02,930 but design them based on all of the available information 377 00:17:02,930 --> 00:17:06,282 and continue this pursuit of what Venus is all about. 378 00:17:06,282 --> 00:17:08,227 (dramatic music) 379 00:17:08,227 --> 00:17:10,240 Mariner 2s distant flyby 380 00:17:10,240 --> 00:17:13,820 hadn't settled the score for supremacy over Venus, 381 00:17:13,820 --> 00:17:16,840 but the USA and the USSR were about to begin 382 00:17:16,840 --> 00:17:20,780 an even more intense battle for Earth's twin. 383 00:17:20,780 --> 00:17:24,070 From now on once Mariner 2 did the job, 384 00:17:24,070 --> 00:17:27,200 it was absolutely paramount for the Soviet Union 385 00:17:27,200 --> 00:17:29,630 to land on the surface of Venus first 386 00:17:29,630 --> 00:17:31,990 and preferably to do imagery 387 00:17:31,990 --> 00:17:34,660 and science on the surface of Venus. 388 00:17:34,660 --> 00:17:36,440 Over the next 11 years, 389 00:17:36,440 --> 00:17:39,141 there was a frenzy of missions to Venus 390 00:17:39,141 --> 00:17:42,808 (dramatic theatrical music) 391 00:17:48,271 --> 00:17:51,938 (bright lighthearted music) 392 00:17:54,870 --> 00:17:57,400 Venera 9 is plangently increasingly 393 00:17:57,400 --> 00:17:59,093 dense atmosphere of Venus. 394 00:17:59,093 --> 00:18:00,590 (bright theatrical music) 395 00:18:00,590 --> 00:18:03,610 About 50 kilometers up from the surface of Venus, 396 00:18:03,610 --> 00:18:07,670 you pass through a region that is about 397 00:18:07,670 --> 00:18:11,200 the surface temperature and pressure of Earth, 398 00:18:11,200 --> 00:18:13,850 so there's a region in the upper atmosphere of Venus 399 00:18:13,850 --> 00:18:17,300 that would feel pretty much like it feels in this room. 400 00:18:17,300 --> 00:18:19,320 I think to any individual 401 00:18:19,320 --> 00:18:22,670 who reads the description of the landing sequence, 402 00:18:22,670 --> 00:18:24,230 thinks that it's really irrational 403 00:18:24,230 --> 00:18:26,610 and a really bizarre way to get 404 00:18:26,610 --> 00:18:28,660 equipment to the surface of Venus, 405 00:18:28,660 --> 00:18:31,530 But after a little bit close examination, 406 00:18:31,530 --> 00:18:33,420 we understand that each steps of the sequence 407 00:18:33,420 --> 00:18:35,860 there's actually logic and behind it. 408 00:18:35,860 --> 00:18:38,020 And, in fact, it's counterintuitive, 409 00:18:38,020 --> 00:18:41,100 but part of the problem with a lot of designs 410 00:18:41,100 --> 00:18:43,740 when you're designing an entry probe for Venus 411 00:18:43,740 --> 00:18:45,500 is that you fall too slowly, 412 00:18:45,500 --> 00:18:47,540 Meaning that, it takes too long, 413 00:18:47,540 --> 00:18:48,850 and you're gonna heat up too much 414 00:18:48,850 --> 00:18:50,350 before you get to the surface. 415 00:18:54,100 --> 00:18:55,330 Then you keep falling, 416 00:18:55,330 --> 00:18:57,270 and the atmosphere gets hotter and hotter 417 00:18:57,270 --> 00:19:00,570 and more and more dense to the point where 418 00:19:00,570 --> 00:19:04,850 it's a hundred times as dense as the atmosphere on Earth. 419 00:19:04,850 --> 00:19:07,100 That means that you're falling through. 420 00:19:07,100 --> 00:19:09,190 It's not quite a liquid, but it's a gas 421 00:19:09,190 --> 00:19:11,400 that is approaching the properties of a liquid, 422 00:19:11,400 --> 00:19:13,117 and that would slow your fall. 423 00:19:13,117 --> 00:19:15,840 (voice chattering on radio) 424 00:19:15,840 --> 00:19:16,960 Then when you get to the surface, 425 00:19:16,960 --> 00:19:18,913 it's almost like going through the ocean. 426 00:19:18,913 --> 00:19:20,470 (gentle music) 427 00:19:20,470 --> 00:19:22,540 Venera 9 wasn't the first Lander 428 00:19:22,540 --> 00:19:24,313 to get to the surface of Venus, 429 00:19:25,278 --> 00:19:27,913 but it was the first to send back pictures. 430 00:19:29,580 --> 00:19:31,805 It was a colossal achievement. 431 00:19:31,805 --> 00:19:35,222 (gentle dramatic music) 432 00:19:37,420 --> 00:19:40,240 Venera 9 returned the first pictures 433 00:19:40,240 --> 00:19:43,000 from the surface of another planet, 434 00:19:43,000 --> 00:19:45,650 and the fact that, that was done first for Venus 435 00:19:45,650 --> 00:19:50,160 before the Americans did it with a Viking in 1976 at Mars 436 00:19:50,160 --> 00:19:52,990 is really remarkable because it's much harder to land 437 00:19:52,990 --> 00:19:56,410 on Venus and photograph it than it is on Mars. 438 00:19:56,410 --> 00:19:58,370 Not that Mars is a picnic, 439 00:19:58,370 --> 00:20:00,880 but just to get something to survive 440 00:20:00,880 --> 00:20:03,330 in those conditions and take a photograph 441 00:20:03,330 --> 00:20:06,730 and send the results back is really challenging. 442 00:20:06,730 --> 00:20:10,770 That achievement in 1975 by the Soviet Union 443 00:20:10,770 --> 00:20:13,886 that was a real triumph of exploration. 444 00:20:13,886 --> 00:20:16,640 (gentle music) 445 00:20:16,640 --> 00:20:19,900 What we have from the Russian is just unbelievable 446 00:20:19,900 --> 00:20:23,030 because it was really a challenge to land there. 447 00:20:23,030 --> 00:20:25,460 So even if the images are not perfect, 448 00:20:25,460 --> 00:20:27,397 it's still wonderful. 449 00:20:29,157 --> 00:20:33,300 But the ideas of Venus as a verdant lovely environment, 450 00:20:33,300 --> 00:20:35,400 possibly with jungles on the surface 451 00:20:35,400 --> 00:20:39,223 and a water rich environment, were immediately taken away. 452 00:20:41,685 --> 00:20:43,610 It wasn't really until Venera 9 453 00:20:43,610 --> 00:20:45,660 operated at the surface for some time 454 00:20:45,660 --> 00:20:48,450 and returned data that we were sure that we had 455 00:20:48,450 --> 00:20:50,870 solid data that told us, yes, this is how hot 456 00:20:50,870 --> 00:20:52,240 and this is what the pressure. 457 00:20:52,240 --> 00:20:54,543 Wow, that's really pretty intense. 458 00:20:54,543 --> 00:20:56,164 (dramatic music) 459 00:20:56,164 --> 00:20:57,640 (thunder roaring) 460 00:20:57,640 --> 00:21:01,030 After Venera 9, we had a sense 461 00:21:01,030 --> 00:21:05,520 of what some individual places on Venus were like. 462 00:21:05,520 --> 00:21:07,270 If you send a probe in one place 463 00:21:07,270 --> 00:21:08,240 and you measure the temperature 464 00:21:08,240 --> 00:21:09,750 and pressure on the way down, 465 00:21:09,750 --> 00:21:14,130 it gives you one slice from space to the surface. 466 00:21:14,130 --> 00:21:16,620 But the more we learned about Venus, 467 00:21:16,620 --> 00:21:18,370 the more we realize that 468 00:21:18,370 --> 00:21:20,920 like Earth it's a complex changing planet 469 00:21:20,920 --> 00:21:22,910 with different things going on in the day side 470 00:21:22,910 --> 00:21:25,750 and the night side and this latitude and that latitude, 471 00:21:25,750 --> 00:21:29,050 and that to really understand what's going on, 472 00:21:29,050 --> 00:21:32,070 you have to measure multiple places at once. 473 00:21:32,070 --> 00:21:34,370 If you have this probe on the night side, 474 00:21:34,370 --> 00:21:35,650 and this probe on the day side, 475 00:21:35,650 --> 00:21:36,920 and this probe at high latitude, 476 00:21:36,920 --> 00:21:38,380 and this probe at low latitude 477 00:21:38,380 --> 00:21:40,680 and you're able to do them all at once, 478 00:21:40,680 --> 00:21:44,010 then you can put together more of a 3D picture 479 00:21:44,010 --> 00:21:45,830 of the way the atmosphere is behaving 480 00:21:45,830 --> 00:21:47,313 and changing over time. 481 00:21:48,710 --> 00:21:51,080 In 1974, NASA approved 482 00:21:51,080 --> 00:21:53,480 a double mission to explore Venus, 483 00:21:53,480 --> 00:21:58,030 both from orbit and from multiple places around the planet. 484 00:21:58,030 --> 00:22:01,923 This ambitious mission was called Pioneer Venus, 485 00:22:03,340 --> 00:22:06,210 The Pioneer Venus mission included an Orbiter 486 00:22:06,210 --> 00:22:09,460 and four probes, three small probes 487 00:22:09,460 --> 00:22:11,040 and one large probe to look 488 00:22:11,040 --> 00:22:13,900 at different parts of the global Venus 489 00:22:13,900 --> 00:22:17,193 and to make measurements as they descended to the surface. 490 00:22:18,320 --> 00:22:20,110 The Pioneer Venus Orbiter 491 00:22:20,110 --> 00:22:22,810 launched in May in 1978, 492 00:22:22,810 --> 00:22:25,050 and the spacecraft carrying the probes 493 00:22:25,050 --> 00:22:26,940 followed it in August. 494 00:22:26,940 --> 00:22:30,160 The Orbiter had arrived at Venus a few days earlier 495 00:22:30,160 --> 00:22:33,300 and inserted itself into orbit in preparation 496 00:22:33,300 --> 00:22:37,180 to relay data back from atmospheric probes. 497 00:22:37,180 --> 00:22:41,270 The probes were not designed to survive the landing, 498 00:22:41,270 --> 00:22:43,730 but fortunately one did 499 00:22:43,730 --> 00:22:46,170 and continued to send back information 500 00:22:46,170 --> 00:22:49,853 until the heat of the surface destroyed its electronics. 501 00:22:51,290 --> 00:22:52,123 The results from the 502 00:22:52,123 --> 00:22:54,550 Pioneer Venus mission were clear. 503 00:22:54,550 --> 00:22:56,710 No matter where you went on Venus, 504 00:22:56,710 --> 00:22:58,840 the night side, the day side, 505 00:22:58,840 --> 00:23:01,470 the equator, or the higher latitudes, 506 00:23:01,470 --> 00:23:05,463 its surface was uniformly hot and at high pressure. 507 00:23:07,690 --> 00:23:09,210 So Venus is all bad. 508 00:23:09,210 --> 00:23:11,170 The temperature only varies by a degree 509 00:23:11,170 --> 00:23:12,960 or two over the whole globe, 510 00:23:12,960 --> 00:23:15,940 day to night, pole to equator, 511 00:23:15,940 --> 00:23:19,740 and the thick atmosphere acts like a blanket, 512 00:23:19,740 --> 00:23:24,000 which keeps the entire surface of Venus very hot, 513 00:23:24,000 --> 00:23:26,140 and so there's no place, 514 00:23:26,140 --> 00:23:29,150 no hospitable place on the surface of Venus, 515 00:23:29,150 --> 00:23:31,623 where we might imagine humans living. 516 00:23:33,060 --> 00:23:34,980 It's not just the temperature. 517 00:23:34,980 --> 00:23:37,390 The atmospheric pressure on the surface 518 00:23:37,390 --> 00:23:40,480 is so high that it would crush almost 519 00:23:40,480 --> 00:23:42,903 every military submarine ever built. 520 00:23:43,990 --> 00:23:47,830 Now we see Venus is just awful environment. 521 00:23:47,830 --> 00:23:49,460 I mean the atmosphere is only 522 00:23:49,460 --> 00:23:52,993 CO2 is 90 bars on the surface and 500 degrees. 523 00:23:54,350 --> 00:23:55,800 By the end of the '70s, 524 00:23:55,800 --> 00:23:58,760 we really understood how Venus looked. 525 00:23:58,760 --> 00:24:01,830 I mean, it was not gonna be habitable. 526 00:24:01,830 --> 00:24:04,680 And to me that had sort of a lingering effect 527 00:24:04,680 --> 00:24:07,190 that Venus was like not as exciting 528 00:24:07,190 --> 00:24:08,500 as it was supposed to be, 529 00:24:08,500 --> 00:24:10,850 and, therefore, it was sort of not as cool 530 00:24:10,850 --> 00:24:13,560 and maybe not as worthy of our attention. 531 00:24:13,560 --> 00:24:15,060 I think that was really unfortunate 532 00:24:15,060 --> 00:24:17,020 because it was an outcome of those 533 00:24:17,020 --> 00:24:19,510 false expectations that we had for it. 534 00:24:19,510 --> 00:24:23,840 So instead of Venus being a sort of tropical paradise, 535 00:24:23,840 --> 00:24:26,400 it's hell things have gone terribly bad. 536 00:24:26,400 --> 00:24:29,530 Temperature on the surface is hot enough to melt lead 537 00:24:29,530 --> 00:24:32,430 and the atmosphere is full of poisonous gases 538 00:24:32,430 --> 00:24:33,905 and carbon dioxide. 539 00:24:33,905 --> 00:24:36,488 (gentle music) 540 00:24:38,020 --> 00:24:40,180 It sets up this huge mystery. 541 00:24:40,180 --> 00:24:43,600 Why do you have these twin planets so nearby, 542 00:24:43,600 --> 00:24:45,752 and one of them ends up like this, 543 00:24:45,752 --> 00:24:49,320 this paradise for Earthly life. 544 00:24:49,320 --> 00:24:53,564 This other one right here ends up in such a different state. 545 00:24:53,564 --> 00:24:56,270 What happened there, 546 00:24:56,270 --> 00:24:57,933 and can that happen here? 547 00:24:58,930 --> 00:25:00,770 If we don't know the answer to that, 548 00:25:00,770 --> 00:25:03,093 how much do we really know about our planet? 549 00:25:03,093 --> 00:25:05,676 (gentle music) 550 00:25:07,570 --> 00:25:09,600 In order to answer these questions, 551 00:25:09,600 --> 00:25:14,112 we must go back to the formation of Venus and Earth. 552 00:25:14,112 --> 00:25:16,862 (dramatic music) 553 00:25:19,110 --> 00:25:21,720 Earth and Venus form this set of twins 554 00:25:21,720 --> 00:25:23,960 that, as far as we can tell, started out more similar, 555 00:25:23,960 --> 00:25:25,960 and then diverged. 556 00:25:25,960 --> 00:25:27,770 Understanding that divergence 557 00:25:27,770 --> 00:25:29,480 is an important scientific puzzle, 558 00:25:29,480 --> 00:25:31,550 but it's also just sort of compelling 559 00:25:31,550 --> 00:25:32,770 because Earth is our home, 560 00:25:32,770 --> 00:25:34,320 and here's this other planet 561 00:25:34,320 --> 00:25:36,570 that could have been like Earth, that should have been, 562 00:25:36,570 --> 00:25:39,680 and yet it's so different. 563 00:25:39,680 --> 00:25:41,880 (dramatic music) 564 00:25:41,880 --> 00:25:43,067 The formation of Venus and Earth 565 00:25:43,067 --> 00:25:44,553 was probably pretty similar. 566 00:25:44,553 --> 00:25:47,740 It's made of the same type of stuff. 567 00:25:47,740 --> 00:25:50,280 It seems as though the original rocky stuff 568 00:25:50,280 --> 00:25:52,820 that fell together and made Earth 569 00:25:52,820 --> 00:25:55,480 probably had a lot of water bound up in it, 570 00:25:55,480 --> 00:25:58,880 and Venus because it seems to have been made out of 571 00:25:58,880 --> 00:26:02,650 the same stuff in the same process at the same time, 572 00:26:02,650 --> 00:26:05,490 then likely got a similar admixture of water 573 00:26:05,490 --> 00:26:08,690 just chemically bound up in that rocky material 574 00:26:08,690 --> 00:26:10,190 that made the original planet. 575 00:26:11,330 --> 00:26:12,850 About 600 million years 576 00:26:12,850 --> 00:26:14,490 after the beginning of the solar system, 577 00:26:14,490 --> 00:26:16,850 there was a very large period of collisions 578 00:26:16,850 --> 00:26:18,800 when the collision rate was very high, 579 00:26:18,800 --> 00:26:20,850 and that's what we call the late heavy bombardment. 580 00:26:20,850 --> 00:26:22,240 So during that time, 581 00:26:22,240 --> 00:26:24,750 there were both comets and asteroids moving around 582 00:26:24,750 --> 00:26:28,458 both bringing even more water to the Earth and Venus. 583 00:26:28,458 --> 00:26:31,320 (gentle music) 584 00:26:31,320 --> 00:26:32,850 After all the brutal drama 585 00:26:32,850 --> 00:26:34,520 of the initial formation 586 00:26:34,520 --> 00:26:37,283 and the violence of the late heavy bombardment, 587 00:26:38,720 --> 00:26:41,660 things would have settled down for Earth and Venus. 588 00:26:41,660 --> 00:26:44,243 (gentle music) 589 00:26:45,230 --> 00:26:48,580 Venus might've been much more hospitable, 590 00:26:48,580 --> 00:26:49,970 very similar to the Earth. 591 00:26:49,970 --> 00:26:53,027 Maybe there were oceans and even life on Venus. 592 00:26:53,027 --> 00:26:55,610 (gentle music) 593 00:27:05,170 --> 00:27:09,420 So why is it that Earth today is an oceanic planet 594 00:27:09,420 --> 00:27:12,830 and Venus is not if they both started out similar? 595 00:27:12,830 --> 00:27:15,190 The one obvious difference is that Venus 596 00:27:15,190 --> 00:27:17,300 is significantly closer to the Sun. 597 00:27:17,300 --> 00:27:18,530 It's about three quarters 598 00:27:18,530 --> 00:27:20,180 of the distance from the Sun to Earth, 599 00:27:20,180 --> 00:27:23,060 which means it gets about twice the amount of sunlight. 600 00:27:23,060 --> 00:27:24,690 When the planets were young, 601 00:27:24,690 --> 00:27:27,100 the Sun was much less bright than it is now. 602 00:27:27,100 --> 00:27:29,080 So there was a time when the ocean of Venus 603 00:27:29,080 --> 00:27:30,203 was probably stable. 604 00:27:32,150 --> 00:27:36,190 What happened we think was that as the Sun heated up, 605 00:27:36,190 --> 00:27:39,063 it triggered something we call the runaway greenhouse, 606 00:27:41,230 --> 00:27:44,130 and the way that works has to do with evaporation. 607 00:27:44,130 --> 00:27:46,420 So if you're evaporating the oceans of a planet, 608 00:27:46,420 --> 00:27:48,447 you're getting more water vapor in the atmosphere. 609 00:27:48,447 --> 00:27:51,720 But water vapor itself is a strong greenhouse gas, 610 00:27:51,720 --> 00:27:53,270 really as strong as CO2, 611 00:27:53,270 --> 00:27:56,450 meaning that it's a gas that absorbs infrared radiation. 612 00:27:56,450 --> 00:27:58,170 It lets the visible through. 613 00:27:58,170 --> 00:27:59,950 It absorbs infrared. 614 00:27:59,950 --> 00:28:02,260 So you get more water vapor, 615 00:28:02,260 --> 00:28:03,300 you're absorbing more infrared. 616 00:28:03,300 --> 00:28:06,710 You have a stronger greenhouse that heats up the surface. 617 00:28:06,710 --> 00:28:09,570 so you get more evaporation and more evaporation, 618 00:28:09,570 --> 00:28:11,680 gives you more water vapor in the atmosphere 619 00:28:11,680 --> 00:28:15,330 a stronger greenhouse, hotter surface, more evaporation. 620 00:28:15,330 --> 00:28:17,450 So you can see it's what we call positive feedback 621 00:28:17,450 --> 00:28:19,200 because the hotter the surface is, 622 00:28:19,200 --> 00:28:20,817 the more water vapor you're getting in the atmosphere. 623 00:28:20,817 --> 00:28:23,160 The more water vapor, the hotter the surface is, 624 00:28:23,160 --> 00:28:25,640 so that each part of the cycle reinforces the other. 625 00:28:25,640 --> 00:28:27,930 That's a positive feedback and that's unstable. 626 00:28:27,930 --> 00:28:29,328 It runs away. 627 00:28:29,328 --> 00:28:32,090 (gentle music) 628 00:28:32,090 --> 00:28:35,130 So water in the oceans evaporated 629 00:28:35,130 --> 00:28:37,060 to make a blanket around the planet, 630 00:28:37,060 --> 00:28:39,970 which made the planet hotter, but worse than that, 631 00:28:39,970 --> 00:28:42,876 carbon dioxide was baked out of rocks. 632 00:28:42,876 --> 00:28:45,330 (dramatic music) 633 00:28:45,330 --> 00:28:47,440 The idea that carbon dioxide 634 00:28:47,440 --> 00:28:50,910 could create a powerful greenhouse effect goes all 635 00:28:50,910 --> 00:28:54,723 the way back to the Swedish pioneer Svante Arrhenius. 636 00:28:55,870 --> 00:28:58,380 Svante Arrhenius correctly deduced 637 00:28:58,380 --> 00:29:01,420 that there was a lot of carbon dioxide in the atmosphere. 638 00:29:01,420 --> 00:29:02,840 So it was probably hot. 639 00:29:02,840 --> 00:29:04,620 In fact, he was also one of the first people 640 00:29:04,620 --> 00:29:07,890 that considered greenhouse warming on Earth. 641 00:29:07,890 --> 00:29:10,280 Interestingly, and that partly came out of his work 642 00:29:10,280 --> 00:29:12,470 on thinking about what Venus was like. 643 00:29:12,470 --> 00:29:14,130 So this is one of the ways, in which, 644 00:29:14,130 --> 00:29:15,720 our knowledge of Earth climate 645 00:29:15,720 --> 00:29:18,590 and global warming is actually connected to thought 646 00:29:18,590 --> 00:29:20,970 about Venus because Arrhenius put this together. 647 00:29:20,970 --> 00:29:23,739 He said a planet with a lot of CO2 has to be warm. 648 00:29:23,739 --> 00:29:25,500 (bright music) 649 00:29:25,500 --> 00:29:28,440 So how did Earth escape the same fate 650 00:29:28,440 --> 00:29:32,230 as Venus with a runaway greenhouse effect? 651 00:29:32,230 --> 00:29:34,703 The answer begins with rain. 652 00:29:35,760 --> 00:29:39,380 So on Earth the CO2 gets pulled out of the atmosphere 653 00:29:39,380 --> 00:29:41,270 by what we call weathering reactions, 654 00:29:41,270 --> 00:29:43,520 where water is raining out 655 00:29:43,520 --> 00:29:45,470 and makes a sort of carbonic acid, 656 00:29:45,470 --> 00:29:49,410 which when it runs over rocks, leaches the ions out 657 00:29:49,410 --> 00:29:52,010 and it ends up in the ocean as carbonate ions 658 00:29:52,010 --> 00:29:53,903 and forms carbonate rocks. 659 00:29:55,210 --> 00:29:56,710 When you see the White Cliffs of Dover 660 00:29:56,710 --> 00:30:00,100 or any massive deposit of carbonates, 661 00:30:00,100 --> 00:30:01,610 you're seeing carbon that has been 662 00:30:01,610 --> 00:30:03,890 pulled out of the atmosphere. 663 00:30:03,890 --> 00:30:05,650 Those carbonate rocks get pulled 664 00:30:05,650 --> 00:30:07,520 into the interior by plate tectonics, 665 00:30:07,520 --> 00:30:10,270 and when you have subduction of oceanic crust 666 00:30:10,270 --> 00:30:13,010 down deep into the interior where they're melted 667 00:30:13,010 --> 00:30:17,020 and ultimately then the CO2 is released under pressure 668 00:30:17,020 --> 00:30:18,760 and becomes a dissolved gas, 669 00:30:18,760 --> 00:30:20,740 which then comes back out those volcanoes 670 00:30:20,740 --> 00:30:22,190 and that completes the cycle. 671 00:30:23,210 --> 00:30:26,590 But that is facilitated by water in rain 672 00:30:26,590 --> 00:30:28,070 and in these chemical reactions. 673 00:30:28,070 --> 00:30:29,270 If you don't have water, 674 00:30:29,270 --> 00:30:31,361 you sort of break that part of the carbon cycle. 675 00:30:31,361 --> 00:30:33,687 (gentle dramatic music) 676 00:30:33,687 --> 00:30:35,390 But if the process that removes 677 00:30:35,390 --> 00:30:38,710 carbon dioxide from the atmosphere is rain, 678 00:30:38,710 --> 00:30:41,200 what happened to Venus' water. 679 00:30:41,200 --> 00:30:43,760 The answer is due to a complex interaction 680 00:30:43,760 --> 00:30:47,290 of the planet's atmosphere and the stream of particles 681 00:30:47,290 --> 00:30:50,623 that constantly come off the Sun called the solar wind. 682 00:30:53,460 --> 00:30:55,480 When the water on a planet evaporates 683 00:30:55,480 --> 00:30:57,430 and is in the atmosphere as water vapor 684 00:30:57,430 --> 00:31:01,130 as opposed to condensed on the surface in liquid water, 685 00:31:01,130 --> 00:31:03,947 then it's much more vulnerable being lost to space, 686 00:31:03,947 --> 00:31:05,800 and the main way that happens 687 00:31:05,800 --> 00:31:09,440 is the water gets broken up by ultraviolet light 688 00:31:09,440 --> 00:31:11,090 in what we call photo dissociation, 689 00:31:11,090 --> 00:31:13,690 which is that these energetic photons of sunlight 690 00:31:13,690 --> 00:31:16,990 breaks hydrogens off from the oxygen. 691 00:31:16,990 --> 00:31:18,900 Then when you have a free floating hydrogen, 692 00:31:18,900 --> 00:31:21,080 it's easy for that to escape into space. 693 00:31:21,080 --> 00:31:22,720 In fact, all planets are losing hydrogen 694 00:31:22,720 --> 00:31:24,200 all the time into space, 695 00:31:24,200 --> 00:31:26,027 and when you have a steam atmosphere 696 00:31:26,027 --> 00:31:28,790 and a lot of water photo dissociating, 697 00:31:28,790 --> 00:31:30,530 then you're gonna have a stream of hydrogen 698 00:31:30,530 --> 00:31:32,200 escaping off into space. 699 00:31:32,200 --> 00:31:33,480 Then after a period of time, 700 00:31:33,480 --> 00:31:34,710 you're left with less hydrogen, 701 00:31:34,710 --> 00:31:36,350 and, therefore, less water on the planet. 702 00:31:36,350 --> 00:31:37,680 The solar wind is a stream 703 00:31:37,680 --> 00:31:40,060 of charged particles coming out of the Sun. 704 00:31:40,060 --> 00:31:41,920 That is what is stripping away 705 00:31:41,920 --> 00:31:43,860 the atmospheres of the planets. 706 00:31:43,860 --> 00:31:46,540 All this means that you're sort of losing water, 707 00:31:46,540 --> 00:31:49,130 and so Venus is becoming drier and drier. 708 00:31:49,130 --> 00:31:51,340 So Earth has a magnetic field which protects it 709 00:31:51,340 --> 00:31:54,000 to some extent from the onslaught of the solar wind. 710 00:31:54,000 --> 00:31:56,010 Whereas, Venus we have no magnetic field 711 00:31:56,010 --> 00:31:57,560 to protect the planet. 712 00:31:57,560 --> 00:31:59,830 A decade or so ago people used to think 713 00:31:59,830 --> 00:32:02,940 that the big difference between Earth and Venus 714 00:32:02,940 --> 00:32:05,250 was that the Earth had a magnetic field, 715 00:32:05,250 --> 00:32:07,560 and then we looked at Venus and we said 716 00:32:07,560 --> 00:32:08,810 it's lost all its water 717 00:32:08,810 --> 00:32:10,910 because solar wind strips it away. 718 00:32:10,910 --> 00:32:13,230 We are finding it's more subtle now. 719 00:32:13,230 --> 00:32:14,950 Pretty much all of the planets 720 00:32:14,950 --> 00:32:18,600 lose their atmosphere right now at about the same rate, 721 00:32:18,600 --> 00:32:20,470 so everything's scrambled. 722 00:32:20,470 --> 00:32:22,080 We're back to the drawing board 723 00:32:22,080 --> 00:32:26,360 to really try to understand how atmospheric escape what, 724 00:32:26,360 --> 00:32:27,870 and what role, if any, 725 00:32:27,870 --> 00:32:30,213 the magnetic field plays in that process. 726 00:32:31,500 --> 00:32:33,910 Whether or not the lack of a magnetic field 727 00:32:33,910 --> 00:32:36,970 had accelerated the loss of Venus' water. 728 00:32:36,970 --> 00:32:39,070 The planet became dry 729 00:32:39,070 --> 00:32:41,737 and had no chance to mop up all the CO2. 730 00:32:43,740 --> 00:32:45,387 (gentle music) 731 00:32:45,387 --> 00:32:48,085 But where did all this gas come from? 732 00:32:48,085 --> 00:32:49,470 (gentle music) 733 00:32:49,470 --> 00:32:51,790 Why was the atmosphere of Venus 734 00:32:51,790 --> 00:32:54,350 so much thicker than our own? 735 00:32:54,350 --> 00:32:56,410 To find out, scientists would need 736 00:32:56,410 --> 00:32:59,203 to find a way to see what was going on. 737 00:33:01,090 --> 00:33:02,440 One of the fantastic things 738 00:33:02,440 --> 00:33:04,450 about Venus is its cloud layer. 739 00:33:04,450 --> 00:33:07,130 This is what makes it shine like a beacon in the sky. 740 00:33:07,130 --> 00:33:09,900 At the same time, it's one of the most frustrating things 741 00:33:09,900 --> 00:33:12,320 because it stops us seeing the surface. 742 00:33:12,320 --> 00:33:14,470 So what we need to do is not look with our eyes 743 00:33:14,470 --> 00:33:16,260 but look with different wavelengths 744 00:33:16,260 --> 00:33:17,790 that can peer through these clouds 745 00:33:17,790 --> 00:33:20,910 and get down to the surface, such as radar wave lengths, 746 00:33:20,910 --> 00:33:23,210 and then we can certainly see what's going on. 747 00:33:25,870 --> 00:33:29,893 After the success of Venera 9 and 10 in 1975, 748 00:33:31,590 --> 00:33:33,510 the Soviets continued to send 749 00:33:33,510 --> 00:33:35,573 a variety of missions to Venus. 750 00:33:36,538 --> 00:33:39,121 (gentle music) 751 00:33:48,557 --> 00:33:51,400 But NASA was determined to try and find out 752 00:33:51,400 --> 00:33:54,483 what much of the surface of Venus actually looked like, 753 00:33:55,686 --> 00:33:57,020 and in the early '80s, 754 00:33:57,020 --> 00:33:59,633 they started to develop a mission to do that, 755 00:34:00,890 --> 00:34:04,140 called the Venus Orbiting Imaging Radar. 756 00:34:04,140 --> 00:34:06,030 (gentle music) 757 00:34:06,030 --> 00:34:09,960 It had multiple instruments and multiple antennas 758 00:34:09,960 --> 00:34:13,090 and NASA said there's no money. 759 00:34:13,090 --> 00:34:18,090 And so, this great thing narrowed down to one instrument, 760 00:34:18,570 --> 00:34:20,400 and we were a spare parts mission. 761 00:34:20,400 --> 00:34:22,550 We used a Voyager spare antenna, 762 00:34:22,550 --> 00:34:26,710 and a Voyager spare bus, and Galileo computers, 763 00:34:26,710 --> 00:34:29,520 but the radar itself was a new design. 764 00:34:29,520 --> 00:34:31,310 It had this parabolic antenna, 765 00:34:31,310 --> 00:34:34,530 so the signal would ping off Venus and come back, 766 00:34:34,530 --> 00:34:36,230 and you'd have to capture it. 767 00:34:36,230 --> 00:34:38,010 You synthesize an image from that. 768 00:34:38,010 --> 00:34:39,380 You do it over, and over, and over again, 769 00:34:39,380 --> 00:34:43,730 and you gradually build up radar images of the surface. 770 00:34:43,730 --> 00:34:45,390 The budget version of the mission 771 00:34:45,390 --> 00:34:49,163 made from old spare parts was renamed Magellan, 772 00:34:51,410 --> 00:34:54,570 and on the 4th of May 1989, 773 00:34:54,570 --> 00:34:55,807 it was delivered to low Earth orbit. 774 00:34:55,807 --> 00:34:57,620 12, 11. (funky music) 775 00:34:57,620 --> 00:34:59,590 By space shuttle Atlantis. 776 00:34:59,590 --> 00:35:01,579 Zero, and lift off. 777 00:35:01,579 --> 00:35:04,616 (funky electric music) 778 00:35:04,616 --> 00:35:07,520 There's the Orbiter going by the launch tower. 779 00:35:07,520 --> 00:35:10,390 The last one seems to be throttle down. 780 00:35:11,630 --> 00:35:15,430 So the design of Magellan was to get into an orbit. 781 00:35:15,430 --> 00:35:18,370 If Venus is here, it would go by really close 782 00:35:18,370 --> 00:35:20,930 for an hour and radar image, 783 00:35:20,930 --> 00:35:22,580 and then it would turn back to the Earth 784 00:35:22,580 --> 00:35:25,250 and relay back its data for another hour. 785 00:35:25,250 --> 00:35:28,520 And then it would correct its wheels and get a star scan, 786 00:35:28,520 --> 00:35:31,420 and then turn back and then radar image again, 787 00:35:31,420 --> 00:35:35,673 and we did this 24 seven for a Venus day. 788 00:35:37,577 --> 00:35:38,770 (gentle music) 789 00:35:38,770 --> 00:35:42,880 This is 1989, 1990, 1991. 790 00:35:42,880 --> 00:35:45,420 We're dealing with reel to reel tapes, 791 00:35:45,420 --> 00:35:47,160 and they're running these tapes 792 00:35:47,160 --> 00:35:48,840 back and forth from Goldstone. 793 00:35:48,840 --> 00:35:52,560 And then the data from Canberra and from Madrid 794 00:35:52,560 --> 00:35:56,530 would actually be flown in in overseas packages. 795 00:35:56,530 --> 00:35:58,610 The extreme efforts that the scientists 796 00:35:58,610 --> 00:36:02,980 and engineers made to acquire this data was worth it. 797 00:36:02,980 --> 00:36:05,860 Magellan provided an unprecedented view 798 00:36:05,860 --> 00:36:07,653 of the Venusian surface. 799 00:36:09,230 --> 00:36:11,407 They mapped near to the entire surface of Venus 800 00:36:11,407 --> 00:36:13,520 and that was a huge revelation 801 00:36:13,520 --> 00:36:16,040 because that was our first global look at 802 00:36:16,040 --> 00:36:18,090 what the geology of Venus is really like. 803 00:36:20,500 --> 00:36:23,250 The Magellan data was indisputable. 804 00:36:23,250 --> 00:36:28,163 Venus is or was a world of volcanoes of all kinds. 805 00:36:29,520 --> 00:36:31,940 It told us, yes, this is a world that's dominated 806 00:36:31,940 --> 00:36:34,810 by vulcanism has been through much of its history. 807 00:36:34,810 --> 00:36:35,643 (dramatic music) 808 00:36:35,643 --> 00:36:37,680 It's a world that has been 809 00:36:37,680 --> 00:36:40,514 resurfaced by volcanism over time. 810 00:36:40,514 --> 00:36:42,060 (dramatic music) 811 00:36:42,060 --> 00:36:43,750 There's a huge abundance 812 00:36:43,750 --> 00:36:46,733 and variety of volcanism on Venus. 813 00:36:47,570 --> 00:36:49,640 There are these huge areas of flood basalts 814 00:36:49,640 --> 00:36:52,160 where this running lava has come out from the interior, 815 00:36:52,160 --> 00:36:54,091 and a lot of Venus is covered with that. 816 00:36:54,091 --> 00:36:56,146 (suspenseful music) 817 00:36:56,146 --> 00:36:58,010 But then there are other volcanic features, 818 00:36:58,010 --> 00:37:00,020 these things nicknamed pancake domes, 819 00:37:00,020 --> 00:37:01,080 which are much smaller. 820 00:37:01,080 --> 00:37:03,120 They're about 10 kilometers across 821 00:37:03,120 --> 00:37:05,650 because they're much more sticky, 822 00:37:05,650 --> 00:37:08,264 less runny, more viscous magma. 823 00:37:08,264 --> 00:37:10,040 (suspenseful music) 824 00:37:10,040 --> 00:37:13,200 So it's been a volcanically active planet massively 825 00:37:13,200 --> 00:37:15,390 with all different kinds of volcanism 826 00:37:15,390 --> 00:37:17,050 going through many different phases. 827 00:37:17,050 --> 00:37:18,300 Now it doesn't mean that it's current. 828 00:37:18,300 --> 00:37:19,363 It could be ancient. 829 00:37:22,680 --> 00:37:25,110 All of this activity means that Venus 830 00:37:25,110 --> 00:37:28,520 has been belching carbon dioxide into its atmosphere 831 00:37:28,520 --> 00:37:30,263 for billions of years, 832 00:37:31,400 --> 00:37:34,520 and with no rain to absorb the CO2, 833 00:37:34,520 --> 00:37:37,599 the atmosphere has become thicker and thicker. 834 00:37:37,599 --> 00:37:39,869 (gentle music) 835 00:37:39,869 --> 00:37:42,950 (thunder roars) 836 00:37:42,950 --> 00:37:46,430 The atmosphere on Venus today is almost all CO2 837 00:37:46,430 --> 00:37:47,850 and here on Earth we're concerned 838 00:37:47,850 --> 00:37:51,070 about 300, 400 parts per million CO2. 839 00:37:51,070 --> 00:37:52,020 It's a trace gas. 840 00:37:52,020 --> 00:37:53,336 It's a minor gas. 841 00:37:53,336 --> 00:37:55,919 (gentle music) 842 00:37:59,890 --> 00:38:02,990 If we assume that Venus and Earth started out similar, 843 00:38:02,990 --> 00:38:04,120 which I think is likely, 844 00:38:04,120 --> 00:38:06,230 although we still wanna gather the data to prove it, 845 00:38:06,230 --> 00:38:09,380 that Venus had early oceans more like Earth 846 00:38:09,380 --> 00:38:11,330 and had some kind of a tectonic cycle 847 00:38:11,330 --> 00:38:13,240 and probably a carbon cycle with carbonates 848 00:38:13,240 --> 00:38:16,738 and volcanoes like Earth has today, then what happened? 849 00:38:16,738 --> 00:38:18,720 (dramatic music) (thunder rumbling) 850 00:38:18,720 --> 00:38:20,440 Why is the solid part of the planet 851 00:38:20,440 --> 00:38:22,700 the geology apparently so different from Earth's? 852 00:38:22,700 --> 00:38:25,290 And in my view, it probably has to do 853 00:38:25,290 --> 00:38:27,770 with the losing of the water. 854 00:38:27,770 --> 00:38:31,610 That if you lose the water from the surface of the planet, 855 00:38:31,610 --> 00:38:34,580 then over time you're going to also dry out the crust 856 00:38:34,580 --> 00:38:36,080 and the interior of the planet 857 00:38:36,080 --> 00:38:38,650 because you are also out gassing water. 858 00:38:38,650 --> 00:38:40,530 You're losing water through that cycle, 859 00:38:40,530 --> 00:38:43,640 and on Earth you're in gassing water too, 860 00:38:43,640 --> 00:38:46,270 in the sense that, you're pulling water into the interior 861 00:38:46,270 --> 00:38:48,740 all the time through that tectonic cycle. 862 00:38:48,740 --> 00:38:51,230 If you lose that ability to do that 863 00:38:51,230 --> 00:38:53,090 because you don't have any water on the surface, 864 00:38:53,090 --> 00:38:54,390 you're not going to right away 865 00:38:54,390 --> 00:38:56,310 dry out the interior of the planet. 866 00:38:56,310 --> 00:38:58,720 But after a billion, two billion years, 867 00:38:58,720 --> 00:39:00,330 you're going to ultimately end up with 868 00:39:00,330 --> 00:39:02,680 a dried out interior and a dried out crust, 869 00:39:02,680 --> 00:39:05,550 and that's going to have different material properties. 870 00:39:05,550 --> 00:39:08,920 And, in fact, if you take an Earth model of plate tectonics 871 00:39:08,920 --> 00:39:12,540 and mantle convection and you dry it out, 872 00:39:12,540 --> 00:39:14,927 you change the properties of the rocks and say, 873 00:39:14,927 --> 00:39:16,217 "Well, what if these were dry rocks 874 00:39:16,217 --> 00:39:18,500 "instead of hydrated rocks," 875 00:39:18,500 --> 00:39:21,260 these models will start behaving more like Venus. 876 00:39:21,260 --> 00:39:22,520 The rocks get harder. 877 00:39:22,520 --> 00:39:24,270 It gets harder to subduct. 878 00:39:24,270 --> 00:39:26,400 Plate tectonics gets sort of choked off, 879 00:39:26,400 --> 00:39:28,670 and it's like the engine runs out of lubrication 880 00:39:28,670 --> 00:39:32,630 and it gets stuck and then starts going in spurts 881 00:39:32,630 --> 00:39:34,626 rather than running smoothly. 882 00:39:34,626 --> 00:39:35,800 (gentle dramatic music) 883 00:39:35,800 --> 00:39:38,040 And this drying up of the crust 884 00:39:38,040 --> 00:39:39,960 could be responsible for the lack of 885 00:39:39,960 --> 00:39:42,600 what's known as an internal dynamo, 886 00:39:42,600 --> 00:39:45,144 which is what produces a magnetic field. 887 00:39:45,144 --> 00:39:48,160 (gentle music) 888 00:39:48,160 --> 00:39:50,030 I think the easiest explanation 889 00:39:50,030 --> 00:39:52,320 for why Venus doesn't have a dynamo 890 00:39:52,320 --> 00:39:56,400 is probably that heat is trapped within the core. 891 00:39:56,400 --> 00:39:57,810 It appears right now 892 00:39:57,810 --> 00:40:00,180 that there's no plate tectonics on Venus. 893 00:40:00,180 --> 00:40:03,150 There's probably convection occurring within the mantle, 894 00:40:03,150 --> 00:40:06,170 but it's not very efficient at getting heat out, 895 00:40:06,170 --> 00:40:08,880 and so that probably traps heat within the core. 896 00:40:08,880 --> 00:40:10,650 If heat can't get out, 897 00:40:10,650 --> 00:40:14,010 then I can't cool that fluid at the surface. 898 00:40:14,010 --> 00:40:16,700 I can't release those dense blobs 899 00:40:16,700 --> 00:40:19,450 into the interior falling and convecting. 900 00:40:19,450 --> 00:40:22,330 If it's not convecting and there's none of that 901 00:40:22,330 --> 00:40:25,363 turbulent convection to stir up a magnetic field, 902 00:40:26,200 --> 00:40:29,470 I think you should then see what you do see. 903 00:40:29,470 --> 00:40:30,610 (gentle music) 904 00:40:30,610 --> 00:40:32,120 Magellan orbited Venus 905 00:40:32,120 --> 00:40:36,143 from August 1990 until October 1994. 906 00:40:37,950 --> 00:40:41,320 The mission mapped 98% of the surface 907 00:40:41,320 --> 00:40:44,010 and greatly increased our understanding 908 00:40:44,010 --> 00:40:45,700 of the geological processes 909 00:40:45,700 --> 00:40:47,772 that have shaped the planet's history. 910 00:40:47,772 --> 00:40:48,960 (gentle music) 911 00:40:48,960 --> 00:40:52,070 And by that time, it was done. 912 00:40:52,070 --> 00:40:54,160 The computers were resetting. 913 00:40:54,160 --> 00:40:55,610 We were out of fuel, 914 00:40:55,610 --> 00:40:57,280 and then you gotta update 915 00:40:57,280 --> 00:40:59,010 because now your timing's off 916 00:40:59,010 --> 00:41:00,850 because you've got slightly out of orbit 917 00:41:00,850 --> 00:41:02,830 because of your thrusters. 918 00:41:02,830 --> 00:41:06,090 It was always an engineering challenge 919 00:41:06,090 --> 00:41:08,580 because I was just scrambling every day 920 00:41:08,580 --> 00:41:10,270 just to keep it going. 921 00:41:10,270 --> 00:41:14,030 But it was a great spacecraft to be your first spacecraft 922 00:41:14,030 --> 00:41:17,662 because it was a hell of a learning experience for me. 923 00:41:17,662 --> 00:41:20,440 (gentle music) 924 00:41:20,440 --> 00:41:22,130 The last communication with 925 00:41:22,130 --> 00:41:26,360 Magellan was on the 13th of October 1994, 926 00:41:26,360 --> 00:41:28,880 before the spacecraft disintegrated 927 00:41:28,880 --> 00:41:31,927 deep in Venus's thick atmosphere. 928 00:41:31,927 --> 00:41:33,440 In the aftermath of Magellan, 929 00:41:33,440 --> 00:41:36,160 there was a lot of desire for more Venus missions, 930 00:41:36,160 --> 00:41:39,690 and a lot of frustration in the community of the inability 931 00:41:39,690 --> 00:41:42,520 to get NASA to send another mission to Venus, 932 00:41:42,520 --> 00:41:44,520 which is a effort that continues. 933 00:41:44,520 --> 00:41:45,890 But the European sort of came 934 00:41:45,890 --> 00:41:48,130 to our rescue with Venus Express. 935 00:41:48,130 --> 00:41:51,010 It's called Venus Express because 936 00:41:51,010 --> 00:41:53,640 it was a mission that was put together very quickly. 937 00:41:53,640 --> 00:41:55,850 There was a spare spacecraft from another mission, 938 00:41:55,850 --> 00:41:58,350 and they had a couple of years to propose 939 00:41:58,350 --> 00:42:00,600 and fly a spacecraft, and the Venus Express Mission 940 00:42:00,600 --> 00:42:02,410 was the one that won. 941 00:42:02,410 --> 00:42:04,750 What Venus Express really is, I think of it 942 00:42:04,750 --> 00:42:07,374 as our first weather satellite at another planet. 943 00:42:07,374 --> 00:42:10,290 (gentle dramatic music) 944 00:42:10,290 --> 00:42:13,280 And as the first Venusian weather satellites 945 00:42:13,280 --> 00:42:16,040 Venus express gave us a much greater insight 946 00:42:16,040 --> 00:42:20,190 into what was really going on with Venus's atmosphere. 947 00:42:20,190 --> 00:42:22,700 (dramatic music) 948 00:42:22,700 --> 00:42:26,880 So Venus Express made these movies of the motions 949 00:42:26,880 --> 00:42:28,520 of the atmosphere at different depths, 950 00:42:28,520 --> 00:42:30,380 and indeed it's quite dynamic. 951 00:42:30,380 --> 00:42:31,840 The atmosphere of Venus does this, 952 00:42:31,840 --> 00:42:33,830 what we call four days super rotation, 953 00:42:33,830 --> 00:42:35,830 where the atmosphere is whipping around. 954 00:42:37,540 --> 00:42:40,320 These high altitude zonal winds 955 00:42:40,320 --> 00:42:42,840 can zip around the equator of Venus 956 00:42:42,840 --> 00:42:46,120 at 360 kilometers per hour. 957 00:42:46,120 --> 00:42:47,400 But above the poles, 958 00:42:47,400 --> 00:42:50,840 the rotational speeds drop almost to zero. 959 00:42:50,840 --> 00:42:53,440 (dramatic music) 960 00:42:53,440 --> 00:42:55,870 The intense heat on the surface of Venus 961 00:42:55,870 --> 00:42:58,620 creates powerful convection currents 962 00:42:58,620 --> 00:43:01,780 that drive a separate lower altitude circulation 963 00:43:01,780 --> 00:43:04,830 of heat from the equator to the poles. 964 00:43:04,830 --> 00:43:07,370 (dramatic music) 965 00:43:07,370 --> 00:43:10,790 With Venus Express we saw these vortices near the poles, 966 00:43:10,790 --> 00:43:12,480 in particular the South Pole of Venus, 967 00:43:12,480 --> 00:43:14,073 which had not been seen before. 968 00:43:14,073 --> 00:43:16,020 There's a little bit of like water down a bath plug, 969 00:43:16,020 --> 00:43:18,673 so seeing that for the first time was very exciting. 970 00:43:20,420 --> 00:43:22,840 Venus is entirely covered by clouds. 971 00:43:22,840 --> 00:43:26,390 These clouds are made up of droplets of sulfuric acid, 972 00:43:26,390 --> 00:43:28,770 so it's arguably the case that Venus 973 00:43:28,770 --> 00:43:33,320 has the worst case of acid rain in the whole solar system. 974 00:43:33,320 --> 00:43:36,020 The acid rain of Venus is created by the 975 00:43:36,020 --> 00:43:39,690 vast amounts of sulfur released through the vulcanism 976 00:43:39,690 --> 00:43:42,023 that has dominated the planet's evolution. 977 00:43:43,630 --> 00:43:46,770 Acid rain is in an extreme state on Venus. 978 00:43:46,770 --> 00:43:49,540 Acid rain has been a problem on Earth downwind of factories, 979 00:43:49,540 --> 00:43:52,430 and by studying it in an extreme case on another planet, 980 00:43:52,430 --> 00:43:53,760 it helps us understand more of the 981 00:43:53,760 --> 00:43:56,630 interaction of acid with water clouds. 982 00:43:56,630 --> 00:43:59,060 But down at the surface of Venus, 983 00:43:59,060 --> 00:44:03,751 things are altogether much calmer and deeply weird. 984 00:44:03,751 --> 00:44:05,630 (gentle music) 985 00:44:05,630 --> 00:44:08,850 Here the wind speeds are very low. 986 00:44:08,850 --> 00:44:10,720 The acid rain has evaporated 987 00:44:10,720 --> 00:44:13,321 long before it gets this far down. 988 00:44:13,321 --> 00:44:16,010 (gentle music) 989 00:44:16,010 --> 00:44:18,330 If you could go to the surface of Venus, 990 00:44:18,330 --> 00:44:19,990 not that we can right now, 991 00:44:19,990 --> 00:44:22,713 I think it would be an incredibly strange experience. 992 00:44:23,550 --> 00:44:24,820 The first thing you would notice is that 993 00:44:24,820 --> 00:44:26,580 the quality of light would be very different 994 00:44:26,580 --> 00:44:28,540 from the quality of light on Earth, 995 00:44:28,540 --> 00:44:31,010 and that's mostly because the light is being filtered 996 00:44:31,010 --> 00:44:33,040 through that incredibly thick atmosphere 997 00:44:33,040 --> 00:44:36,160 and also through the globally extensive clouds. 998 00:44:36,160 --> 00:44:39,763 So it would be kind of a red murky light. 999 00:44:40,620 --> 00:44:41,720 When you look at things, 1000 00:44:41,720 --> 00:44:45,500 you're looking through this massively convective medium 1001 00:44:45,500 --> 00:44:47,827 where because of the temperature you're looking at, 1002 00:44:47,827 --> 00:44:51,749 and the swells and stuff, you see the refraction of light. 1003 00:44:51,749 --> 00:44:54,560 (dramatic music) 1004 00:44:54,560 --> 00:44:56,840 You probably would see that sort of shimmery 1005 00:44:56,840 --> 00:44:59,640 kind of effect that you get in desert areas on Earth 1006 00:44:59,640 --> 00:45:02,020 just because there is a lot of infrared radiation 1007 00:45:02,020 --> 00:45:02,997 coming up out of the surface, 1008 00:45:02,997 --> 00:45:04,690 and that is going to be affecting 1009 00:45:04,690 --> 00:45:07,603 the stability of the atmosphere near the surface. 1010 00:45:10,857 --> 00:45:13,660 You're in this really, really strange environment. 1011 00:45:13,660 --> 00:45:15,890 Any movement you feel resistance, 1012 00:45:15,890 --> 00:45:19,300 and it becomes this viscous fluid-like thing 1013 00:45:19,300 --> 00:45:21,840 that you're having to move through. 1014 00:45:21,840 --> 00:45:23,990 It wouldn't be quite like running through water, 1015 00:45:23,990 --> 00:45:25,210 but you'd be approaching that. 1016 00:45:25,210 --> 00:45:26,200 You'd be somewhere in between 1017 00:45:26,200 --> 00:45:28,470 what we feel running through the air 1018 00:45:28,470 --> 00:45:31,020 and that resistance of trying to run 1019 00:45:31,020 --> 00:45:32,670 through something really viscous. 1020 00:45:32,670 --> 00:45:34,932 It'd be a good workout that's for sure. 1021 00:45:34,932 --> 00:45:37,970 (dramatic music) 1022 00:45:37,970 --> 00:45:40,030 So in the future, 1023 00:45:40,030 --> 00:45:42,250 will there ever be a time when Venus 1024 00:45:42,250 --> 00:45:44,690 might've cleared its dense atmosphere 1025 00:45:44,690 --> 00:45:47,963 and cold enough for humans to live on its surface? 1026 00:45:49,220 --> 00:45:51,370 Some have proposed that Venus might 1027 00:45:51,370 --> 00:45:54,600 once again be hospitable, and potentially 1028 00:45:54,600 --> 00:45:58,410 after volcanic eruptions cease on the surface of Venus. 1029 00:45:58,410 --> 00:45:59,840 I don't buy that. 1030 00:45:59,840 --> 00:46:02,930 I think, the escape rate of the Venus atmosphere 1031 00:46:02,930 --> 00:46:06,670 over time is infinitesimally slow 1032 00:46:06,670 --> 00:46:09,140 compared to the magnitude of the atmosphere. 1033 00:46:09,140 --> 00:46:11,910 The time it might take for the Venus atmosphere 1034 00:46:11,910 --> 00:46:13,540 to be cured in that way, 1035 00:46:13,540 --> 00:46:16,230 would probably match the time that the Sun 1036 00:46:16,230 --> 00:46:18,920 would take to see out the rest of its lifetime, 1037 00:46:18,920 --> 00:46:22,793 swelling into a red giant and engulfing the whole planet. 1038 00:46:25,240 --> 00:46:28,610 So there's really no future time that I can imagine 1039 00:46:28,610 --> 00:46:31,250 where the atmosphere would be lost enough 1040 00:46:31,250 --> 00:46:34,150 so the greenhouse effect would be small enough 1041 00:46:34,150 --> 00:46:37,710 so the surface temperature of Venus would be cool enough 1042 00:46:37,710 --> 00:46:39,557 that life could exist there. 1043 00:46:39,557 --> 00:46:40,720 (thunder rumbles) 1044 00:46:40,720 --> 00:46:42,930 So if Venus is never destined to become 1045 00:46:42,930 --> 00:46:46,993 the paradise we once imagined through natural processes, 1046 00:46:46,993 --> 00:46:48,610 (gentle music) 1047 00:46:48,610 --> 00:46:51,143 what about through deliberate manipulation? 1048 00:46:52,110 --> 00:46:55,020 Can we terraform Venus? 1049 00:46:55,020 --> 00:46:57,630 Terraforming is an interesting concept. 1050 00:46:57,630 --> 00:47:00,030 It's certainly a valuable thought experiment. 1051 00:47:00,030 --> 00:47:02,810 I don't necessarily condone trying this, 1052 00:47:02,810 --> 00:47:04,070 but that's okay cause we're not gonna 1053 00:47:04,070 --> 00:47:06,180 have the ability for a long time. 1054 00:47:06,180 --> 00:47:08,090 We have millennia to sort that out, 1055 00:47:08,090 --> 00:47:09,700 whether we think it's a good idea. 1056 00:47:09,700 --> 00:47:11,340 So maybe the way to do it would be 1057 00:47:11,340 --> 00:47:13,560 to throw a lot of comets at Venus 1058 00:47:13,560 --> 00:47:16,090 where you would both raise up the dust 1059 00:47:16,090 --> 00:47:17,840 from the comet impact to cool it off, 1060 00:47:17,840 --> 00:47:18,810 and then you'd also be sort of 1061 00:47:18,810 --> 00:47:21,060 sprinkling it back with water. 1062 00:47:21,060 --> 00:47:23,070 If you start to have liquid water on the surface, 1063 00:47:23,070 --> 00:47:25,500 then that's gonna restart the cycle 1064 00:47:25,500 --> 00:47:27,120 where you're gonna then be removing 1065 00:47:27,120 --> 00:47:29,790 CO2 out of the atmosphere by weathering. 1066 00:47:29,790 --> 00:47:33,310 It would take awhile it'd build longterm renovation project, 1067 00:47:33,310 --> 00:47:36,560 but there's nothing physically impossible about it. 1068 00:47:36,560 --> 00:47:39,050 The problem with terraforming ideas is that 1069 00:47:39,050 --> 00:47:40,320 right now we're in a situation 1070 00:47:40,320 --> 00:47:42,720 where we're rapidly Venura-forming Earth, 1071 00:47:42,720 --> 00:47:44,410 that is turning it to be more Venus like, 1072 00:47:44,410 --> 00:47:46,820 and so we can't even imagine any of these futures 1073 00:47:46,820 --> 00:47:48,390 unless we get to the point where we're doing a much 1074 00:47:48,390 --> 00:47:52,235 better job of controlling our own actions on Earth. 1075 00:47:52,235 --> 00:47:55,070 (gentle music) 1076 00:47:55,070 --> 00:47:57,480 People talk about us colonizing the solar system, 1077 00:47:57,480 --> 00:48:00,890 escaping from the problems that we have on the planet Earth. 1078 00:48:00,890 --> 00:48:03,550 Maybe there's an asteroid heading towards us, 1079 00:48:03,550 --> 00:48:05,250 which one day will hit the surface 1080 00:48:05,250 --> 00:48:07,710 of the planet and cause extinction, 1081 00:48:07,710 --> 00:48:09,590 and, I think, these are things which are important. 1082 00:48:09,590 --> 00:48:11,620 We're studying them, and we really need to understand 1083 00:48:11,620 --> 00:48:14,450 what the possible longterm dangers are. 1084 00:48:14,450 --> 00:48:16,133 But there's a short-term danger, 1085 00:48:17,540 --> 00:48:18,690 which is climate change, 1086 00:48:18,690 --> 00:48:20,253 and it's happening today. 1087 00:48:21,610 --> 00:48:23,240 What worries me sometimes is this idea 1088 00:48:23,240 --> 00:48:24,920 that we can take human beings away 1089 00:48:24,920 --> 00:48:27,250 from all of the mess that we've created here. 1090 00:48:27,250 --> 00:48:29,860 Sociologically, it seems unlikely that we're just going to 1091 00:48:29,860 --> 00:48:32,520 become the perfect citizen once we crossed 1092 00:48:32,520 --> 00:48:34,900 the 100 kilometer line and go into space. 1093 00:48:34,900 --> 00:48:37,690 But also there's nowhere in the solar system 1094 00:48:37,690 --> 00:48:40,570 that's any better to live than the very worst 1095 00:48:40,570 --> 00:48:42,220 that we could ever do to the planet Earth. 1096 00:48:42,220 --> 00:48:43,930 Whatever we do here, 1097 00:48:43,930 --> 00:48:47,450 it won't be as bad as living on Mars or on Venus 1098 00:48:47,450 --> 00:48:49,190 or anywhere else in the solar system. 1099 00:48:49,190 --> 00:48:51,700 So at the same time as we're looking outwards and exploring, 1100 00:48:51,700 --> 00:48:55,440 we should never forget that this is where we come from, 1101 00:48:55,440 --> 00:48:57,670 and there is no planet B. 1102 00:48:57,670 --> 00:48:59,560 This place has to be looked after as well 1103 00:48:59,560 --> 00:49:02,643 as much as we're looking outwards and beyond. 1104 00:49:03,648 --> 00:49:04,730 (gentle music) 1105 00:49:04,730 --> 00:49:08,150 So perhaps one day, far in the future, 1106 00:49:08,150 --> 00:49:11,730 humankind will not only have the scientific ability 1107 00:49:11,730 --> 00:49:14,617 to make Venus into a paradise, 1108 00:49:14,617 --> 00:49:16,860 but the wisdom to realize 1109 00:49:16,860 --> 00:49:20,381 that we already have a paradise of our own 1110 00:49:20,381 --> 00:49:24,048 (gentle lighthearted music) 1111 00:49:26,466 --> 00:49:29,133 (bright music)