1 00:00:04,680 --> 00:00:07,039 (STEPHEN HAWKING) Let me take you back in time 2 00:00:07,040 --> 00:00:11,039 to a place without the wonders of the modern world. 3 00:00:12,480 --> 00:00:15,759 500 years ago, the Earth was dark, 4 00:00:15,760 --> 00:00:19,759 a place of mystery and superstition. 5 00:00:29,160 --> 00:00:33,159 But then science changed everything. 6 00:00:41,360 --> 00:00:45,359 This series will tell the stories of the British scientists who changed the world. 7 00:00:49,600 --> 00:00:53,599 We have asked some of the great scientists and inventors of today 8 00:00:53,720 --> 00:00:57,399 to tell us about their heroes. 9 00:00:57,400 --> 00:00:59,559 Now let's start her up. 10 00:00:59,560 --> 00:01:02,639 It opened up a whole new world of the very small. 11 00:01:02,640 --> 00:01:06,199 Heat was Thomson's big idea. 12 00:01:06,200 --> 00:01:08,719 For me, Hunter is a true hero. 13 00:01:08,720 --> 00:01:10,079 Exciting possibilities. 14 00:01:10,080 --> 00:01:14,079 He made science in Britain really matter. 15 00:01:14,800 --> 00:01:18,799 Britain has a tremendous scientific legacy that most people know little about. 16 00:01:22,720 --> 00:01:26,719 We want to set the record straight and put science back on the map. 17 00:01:30,600 --> 00:01:34,599 The world is full of wonders, but they become more wonderful 18 00:01:34,720 --> 00:01:38,719 when science looks at them. 19 00:01:49,360 --> 00:01:52,399 Our story began with a handful of men 20 00:01:52,400 --> 00:01:56,399 who started to solve the mysteries of the universe. 21 00:01:58,360 --> 00:02:02,359 Those who came after built on their discoveries and harnessed 22 00:02:03,400 --> 00:02:07,399 steam to make power, hydrogen to fly and electricity to light up the world. 23 00:02:12,360 --> 00:02:16,359 But now we take a darker turn. 24 00:02:16,520 --> 00:02:20,519 The first half of the 20th century was dominated by war. 25 00:02:28,240 --> 00:02:32,239 But war brings with it change alongside horror 26 00:02:32,320 --> 00:02:36,319 and innovation alongside courage. 27 00:02:37,120 --> 00:02:41,119 This film is the story of some of the greatest of the backroom boys, 28 00:02:42,080 --> 00:02:43,839 the scientists and engineers, 29 00:02:43,840 --> 00:02:47,839 who helped us come out of the darkness of war. 30 00:02:57,560 --> 00:03:00,079 (JIM AL-KHALILI) A German reconnaissance pilot 31 00:03:00,080 --> 00:03:03,879 flying over Britain in the autumn of 1939 32 00:03:03,880 --> 00:03:07,879 would look down on a country preparing for war. 33 00:03:08,560 --> 00:03:12,559 He'd see mysterious steel towers ranged along the coast, 34 00:03:13,320 --> 00:03:15,199 and wonder what they were for. 35 00:03:15,200 --> 00:03:19,199 He would see a country that seemed open to attack and even invasion. 36 00:03:25,080 --> 00:03:28,559 The English Channel had kept out Napoleon, 37 00:03:28,560 --> 00:03:32,559 but by 1939, the question was, could it keep out Hitler? 38 00:03:34,080 --> 00:03:35,799 In the age of the aeroplane, 39 00:03:35,800 --> 00:03:39,559 Britain seemed particularly vulnerable to attack. 40 00:03:39,560 --> 00:03:43,559 The First World War had already revealed what airpower could do. 41 00:03:46,360 --> 00:03:49,319 On 25th May, 1917, 42 00:03:49,320 --> 00:03:53,319 21 giant twin-engined Gotha biplanes bombed Folkestone. 43 00:03:55,760 --> 00:03:59,759 They killed 95 people and injured 192 others. 44 00:04:02,160 --> 00:04:06,159 In the 1920s, the great fear was that any new war 45 00:04:06,640 --> 00:04:10,639 would bring massive bombing raids and huge civilian casualties. 46 00:04:11,480 --> 00:04:15,479 So the British built an early warning system which looked like this. 47 00:04:29,800 --> 00:04:33,759 This concrete sound mirror was built in 1928. 48 00:04:33,760 --> 00:04:37,759 It's 20 feet across. It cost a few thousand pounds in today's money, 49 00:04:38,720 --> 00:04:41,119 and didn't work very well. 50 00:04:41,120 --> 00:04:44,559 The operator would stand with a stethoscope in front of it 51 00:04:44,560 --> 00:04:48,559 in the hope of picking up the tell-tale sounds of enemy bombers on their way, 52 00:04:49,160 --> 00:04:51,319 if he was lucky. 53 00:04:51,320 --> 00:04:53,919 The results would be affected by the weather, 54 00:04:53,920 --> 00:04:57,799 and by other distractions, like the sounds of the propellers of ships out at sea. 55 00:04:57,800 --> 00:05:01,799 Obviously something far better was needed. 56 00:05:05,360 --> 00:05:07,799 The first idea for a better system 57 00:05:07,800 --> 00:05:11,799 was like something out of a science fiction film. 58 00:05:11,800 --> 00:05:15,799 In the early 1930s, British intelligence picked up rumours 59 00:05:16,160 --> 00:05:19,399 that German scientists had invented a death ray, 60 00:05:19,400 --> 00:05:23,399 using high-power radio signals to destroy men and aircraft. 61 00:05:26,320 --> 00:05:29,279 The Air Ministry realised that if the Germans had one of these, 62 00:05:29,280 --> 00:05:31,479 then the British wanted one too. 63 00:05:31,480 --> 00:05:36,079 A committee was set up, and a prize of 1,000 was offered 64 00:05:36,080 --> 00:05:40,079 to the first person who could kill a sheep at 100 yards using a death ray. 65 00:05:44,200 --> 00:05:46,719 The prize was never claimed. 66 00:05:46,720 --> 00:05:50,719 So in January 1935, the Committee turned to a man 67 00:05:51,720 --> 00:05:55,719 who they hoped would be able to build them a death ray. 68 00:05:56,040 --> 00:06:00,039 A personal hero of mine, a man whose ingenuity in the face of threat 69 00:06:01,440 --> 00:06:04,199 would change the course of history. 70 00:06:04,200 --> 00:06:08,199 Robert Watson-Watt. 71 00:06:12,520 --> 00:06:16,519 Watson-Watt was a physicist and the government expert on radio waves. 72 00:06:18,000 --> 00:06:20,639 He and a colleague set about calculating 73 00:06:20,640 --> 00:06:24,639 the electromagnetic energy needed to put an enemy bomber out of action. 74 00:06:26,680 --> 00:06:30,679 They quickly showed that a death ray couldn't possibly work. 75 00:06:31,480 --> 00:06:35,479 But they had another idea, and when Watson-Watt submitted his report 76 00:06:36,240 --> 00:06:39,599 to the Ministry, it contained the now famous sentence, 77 00:06:39,600 --> 00:06:43,599 "Although it's impossible to destroy aircraft using radio waves, 78 00:06:44,240 --> 00:06:47,039 "it should be possible to detect them 79 00:06:47,040 --> 00:06:50,919 "using radio energy that bounces back from the aircraft's body." 80 00:06:50,920 --> 00:06:54,919 The Ministry said, "Prove it." 81 00:06:55,200 --> 00:06:58,479 Watson-Watt relished the challenge. 82 00:06:58,480 --> 00:07:00,479 He was the son of a Scottish carpenter 83 00:07:00,480 --> 00:07:04,479 and a proud descendant of steam pioneer James Watt. 84 00:07:06,600 --> 00:07:10,599 In February 1935, on the very same day 85 00:07:11,200 --> 00:07:15,199 that Hitler ordered the establishment of the Luftwaffe as a military air force, 86 00:07:16,680 --> 00:07:19,519 Watson-Watt and his colleague Arnold Wilkins 87 00:07:19,520 --> 00:07:23,519 set up their crucial experiment to detect distant aircraft. 88 00:07:25,640 --> 00:07:29,479 They chose a secret location in Northamptonshire, 89 00:07:29,480 --> 00:07:33,479 just a few miles from the BBC short-wave radio transmitter at Daventry. 90 00:07:37,240 --> 00:07:40,999 The Birth of Radar Memorial. 91 00:07:41,000 --> 00:07:44,999 "On 26th of February 1935, in the field opposite..." 92 00:07:45,560 --> 00:07:49,559 Watson-Watt and Wilkins had arranged for an RAF bomber to fly overhead, 93 00:07:52,000 --> 00:07:55,999 and they tuned their aerials in such a way that the receiving equipment in their van 94 00:07:56,680 --> 00:07:59,799 wouldn't pick up the BBC signal directly, 95 00:07:59,800 --> 00:08:03,079 but only the energy reflected by the bomber. 96 00:08:03,080 --> 00:08:06,799 They found they could track the bomber as far as eight miles away 97 00:08:06,800 --> 00:08:10,199 with blips on a cathode-ray tube. 98 00:08:10,200 --> 00:08:14,199 It was the world's first radar reading. 99 00:08:15,400 --> 00:08:19,279 The man from the Ministry rushed back to London to report success. 100 00:08:19,280 --> 00:08:24,439 Watson-Watt and his colleagues were awarded a grant of 10,000 101 00:08:24,440 --> 00:08:27,759 to build a prototype radar system. 102 00:08:27,760 --> 00:08:31,479 They were given five years to detect an incoming enemy aircraft 103 00:08:31,480 --> 00:08:34,239 at a range of 50 miles. 104 00:08:34,240 --> 00:08:38,239 It took them just five months. 105 00:08:40,400 --> 00:08:44,399 By 1939, there were 20 fully-operational radar stations 106 00:08:45,520 --> 00:08:49,519 stretching all the way along Britain's vulnerable coastline. 107 00:08:52,960 --> 00:08:55,159 20 miles away across the Channel, 108 00:08:55,160 --> 00:08:59,159 the Luftwaffe looked forward to an easy victory, 109 00:08:59,880 --> 00:09:03,879 and the benefits of a surprise attack. 110 00:09:07,880 --> 00:09:10,759 August 13th, 1940. 111 00:09:10,760 --> 00:09:12,839 Adlertag, Eagle Day, 112 00:09:12,840 --> 00:09:16,839 the German codename for the start of Hitler's invasion of Britain. 113 00:09:18,640 --> 00:09:22,639 Over a thousand German aircraft darkened the skies over southern England. 114 00:09:24,040 --> 00:09:26,559 The Luftwaffe had estimated 115 00:09:26,560 --> 00:09:30,559 that it would just take four days to destroy the RAF Southern Command. 116 00:09:32,920 --> 00:09:34,319 All that stood in their way 117 00:09:34,320 --> 00:09:38,319 were the vastly outnumbered British Hurricanes and Spitfires. 118 00:09:38,840 --> 00:09:42,839 That and the secret weapon - Watson-Watt's radar. 119 00:09:43,880 --> 00:09:46,559 It had worked in peacetime testing, 120 00:09:46,560 --> 00:09:50,559 but would it work in the chaos of war? 121 00:09:54,840 --> 00:09:58,719 For three tense months in the late summer of 1940, 122 00:09:58,720 --> 00:10:00,719 the RAF and the Luftwaffe 123 00:10:00,720 --> 00:10:04,719 fought out their deadly duel in the skies above southern Britain. 124 00:10:05,960 --> 00:10:07,599 It was a close-run thing, 125 00:10:07,600 --> 00:10:11,599 but Watson-Watt's radar made a key difference. 126 00:10:12,040 --> 00:10:16,039 It meant Fighter Command knew when the German planes were coming, 127 00:10:17,200 --> 00:10:21,199 and that meant they could get the precious few Spitfires and Hurricanes 128 00:10:21,280 --> 00:10:25,279 into action in the right place at the right time 129 00:10:25,840 --> 00:10:29,839 to intercept and destroy the enemy. 130 00:10:34,560 --> 00:10:38,079 Radar gave Britain the edge, 131 00:10:38,080 --> 00:10:42,079 and without it, the battle would have been lost. 132 00:10:49,360 --> 00:10:52,879 Watson-Watt's invention made our modern world 133 00:10:52,880 --> 00:10:55,319 with its busy skies possible. 134 00:10:55,320 --> 00:10:59,319 Without it, planes would collide and ships would run aground. 135 00:10:59,600 --> 00:11:02,599 And finding ways to hide from radar 136 00:11:02,600 --> 00:11:06,599 is now the Holy Grail of military aircraft design. 137 00:11:08,800 --> 00:11:11,639 (STEPHEN HAWKING) Planes like this would be impossible to fly 138 00:11:11,640 --> 00:11:15,399 without another two British technological miracles 139 00:11:15,400 --> 00:11:19,399 that were to come out of World War Two and help the Allies to victory. 140 00:11:20,280 --> 00:11:22,279 The jet engine 141 00:11:22,280 --> 00:11:26,279 and the computer. 142 00:11:25,820 --> 00:11:28,859 My world, and yours, is run by computers. 143 00:11:28,860 --> 00:11:32,339 70 years ago, they didn't exist, 144 00:11:32,340 --> 00:11:36,299 except in the mind of a brilliant Cambridge mathematician 145 00:11:36,300 --> 00:11:39,379 called Alan Turing. 146 00:11:39,380 --> 00:11:43,379 Nobody can say where the thing he started is going to take the human race. 147 00:11:48,300 --> 00:11:52,019 Alan Turing's story is an extraordinary one, 148 00:11:52,020 --> 00:11:56,019 and I think we should begin at the end. 149 00:12:03,340 --> 00:12:06,739 On 8th June 1954, 150 00:12:06,740 --> 00:12:10,739 Alan Turing's housekeeper found him dead in his house near Manchester. 151 00:12:12,540 --> 00:12:15,899 The postmortem report said it was cyanide poisoning. 152 00:12:15,900 --> 00:12:19,019 His mother always thought it was an accident. 153 00:12:19,020 --> 00:12:21,819 A few people thought he was assassinated. 154 00:12:21,820 --> 00:12:25,819 The coroner's official verdict was suicide. 155 00:12:25,900 --> 00:12:28,659 All three theories have something going for them. 156 00:12:28,660 --> 00:12:32,659 Even his mother's accident theory is not as implausible as it sounds. 157 00:12:33,100 --> 00:12:37,019 Turing did do chemical experiments and he did use cyanide. 158 00:12:37,020 --> 00:12:41,019 The assassination theory, too, could at least point to a motive. 159 00:12:41,380 --> 00:12:45,259 Turing was a security risk. He was eminently blackmailable - 160 00:12:45,260 --> 00:12:48,179 a homosexual at the time when it was illegal - 161 00:12:48,180 --> 00:12:49,899 and he had in his head 162 00:12:49,900 --> 00:12:53,899 some of the most important secrets of the Second World War. 163 00:12:54,580 --> 00:12:57,339 Turing was the presiding genius 164 00:12:57,340 --> 00:13:01,059 of Britain's wartime code-breaking headquarters 165 00:13:01,060 --> 00:13:04,459 and the man who created a code-breaking machine 166 00:13:04,460 --> 00:13:08,459 that was the basis for all computer technology. 167 00:13:10,060 --> 00:13:14,059 This fascination with the idea of a thinking machine 168 00:13:14,140 --> 00:13:17,019 began with a book he was given when he was ten. 169 00:13:17,020 --> 00:13:21,019 One chapter was called Where We Do Our Thinking. 170 00:13:21,620 --> 00:13:24,259 The mind and how it worked would obsess Turing 171 00:13:24,260 --> 00:13:25,939 for the whole of his short life. 172 00:13:25,940 --> 00:13:28,579 At Sherborne School in Dorset, 173 00:13:28,580 --> 00:13:32,179 Turing's passion for science set him apart. 174 00:13:32,180 --> 00:13:36,179 When he was 15, the headmaster said, "He must aim at becoming educated. 175 00:13:37,540 --> 00:13:40,179 "If he is to be solely a scientific specialist, 176 00:13:40,180 --> 00:13:43,539 "he's wasting his time at a public school." 177 00:13:43,540 --> 00:13:47,179 But his school did provide him with an experience 178 00:13:47,180 --> 00:13:51,179 that would shape his life and ours. 179 00:13:52,540 --> 00:13:56,379 Alan fell in love with a boy called Christopher Morcom. 180 00:13:56,380 --> 00:13:59,219 He dreamed that they might go up to Cambridge together, 181 00:13:59,220 --> 00:14:02,699 and Christopher duly won a scholarship in 1929. 182 00:14:02,700 --> 00:14:06,699 But then, tragically, Christopher died of tuberculosis. 183 00:14:07,580 --> 00:14:10,779 Alan was devastated. 184 00:14:10,780 --> 00:14:14,019 In his anguish, he wondered whether there was any way 185 00:14:14,020 --> 00:14:18,019 in which Christopher's mind might have survived the death of his body. 186 00:14:18,100 --> 00:14:21,499 What was the relationship between a mind and a body? 187 00:14:21,500 --> 00:14:25,499 Between mind and matter? 188 00:14:26,060 --> 00:14:29,459 These questions lay behind Turing's determination 189 00:14:29,460 --> 00:14:33,219 to analyse and understand the nature of thought. 190 00:14:33,220 --> 00:14:36,019 He couldn't resurrect his dead friend, 191 00:14:36,020 --> 00:14:38,659 but there was something he could do - 192 00:14:38,660 --> 00:14:42,659 win a maths scholarship to Cambridge, just as Christopher had. 193 00:14:43,580 --> 00:14:46,579 Turing wasn't just a scholar, he liked rowing and running. 194 00:14:46,580 --> 00:14:50,579 He ran marathons. And it was here one day in 1935, 195 00:14:51,260 --> 00:14:54,099 while he was out running in Grantchester Meadows, 196 00:14:54,100 --> 00:14:58,099 that he had one of the greatest mathematical insights of all time. 197 00:15:00,900 --> 00:15:04,899 His great insight was to see how an imaginary machine, 198 00:15:05,460 --> 00:15:09,459 operating with very simple rules but with an infinite amount of time, 199 00:15:10,340 --> 00:15:14,339 could solve any and all conceivable mathematical problems. 200 00:15:16,540 --> 00:15:18,859 The so-called Turing machine 201 00:15:18,860 --> 00:15:22,859 was a logical construct, not a real machine. 202 00:15:23,900 --> 00:15:27,899 But with it, Turing had invented the concept of the programmable computer 203 00:15:29,140 --> 00:15:33,139 years before anybody could see how to build one. 204 00:15:35,300 --> 00:15:38,339 The full power of Turing's revolutionary ideas 205 00:15:38,340 --> 00:15:40,899 would not be appreciated for years, even decades. 206 00:15:40,900 --> 00:15:43,739 And Turing himself was about to get caught up 207 00:15:43,740 --> 00:15:47,739 in something far away from the rarefied beauty of pure mathematics. 208 00:15:50,180 --> 00:15:54,179 Even before war began, Turing's potential as a code-breaker 209 00:15:55,380 --> 00:15:58,459 had been spotted. 210 00:15:58,460 --> 00:16:02,139 So, at the outbreak of war, the 27-year-old Turing 211 00:16:02,140 --> 00:16:05,699 was immediately assigned to Room 47 of the Foreign Office. 212 00:16:05,700 --> 00:16:09,699 This was the postal address of the most secret place in Britain. 213 00:16:13,020 --> 00:16:16,739 This is Bletchley Park, home of the code-breakers, 214 00:16:16,740 --> 00:16:19,139 without whom we'd probably have lost the war. 215 00:16:19,140 --> 00:16:23,139 10,000 people worked here, but in conditions of the utmost secrecy. 216 00:16:23,540 --> 00:16:25,739 Many of them didn't even know what they were doing. 217 00:16:25,740 --> 00:16:28,899 They were led by brilliant mathematicians, engineers, 218 00:16:28,900 --> 00:16:32,899 statisticians, even chess grandmasters and crossword compilers. 219 00:16:35,380 --> 00:16:39,379 And foremost among these quirky intelligences was Alan Turing. 220 00:16:46,980 --> 00:16:50,979 This is Alan Turing's office in Hut 8 at Bletchley Park. 221 00:16:51,300 --> 00:16:55,299 It's been reconstructed to be pretty much the way it would have been. 222 00:16:55,620 --> 00:16:59,619 Turing's eccentricities were legendary and endearing. 223 00:17:00,300 --> 00:17:04,019 He lived in a pub outside Bletchley 224 00:17:04,020 --> 00:17:06,979 and he cycled into work wearing his gas mask, 225 00:17:06,980 --> 00:17:10,979 not for protection against gas, but because he suffered from hay fever. 226 00:17:12,100 --> 00:17:14,779 He chained his tea mug to the radiator 227 00:17:14,780 --> 00:17:17,779 with a padlock for fear anybody else would steal it. 228 00:17:17,780 --> 00:17:19,899 Most people thought he was eccentric, 229 00:17:19,900 --> 00:17:23,899 everybody knew he was a genius. 230 00:17:24,340 --> 00:17:28,339 This is what Turing and his colleagues at Bletchley Park were up against, 231 00:17:28,940 --> 00:17:32,939 the German sophisticated coding device, Enigma. 232 00:17:35,660 --> 00:17:38,619 It was used to encode messages 233 00:17:38,620 --> 00:17:42,619 in a way that was going to be very, very hard to decode. 234 00:17:44,060 --> 00:17:47,139 Imagine that I'm a German radio operator 235 00:17:47,140 --> 00:17:50,139 and I want to send a message. It might be "heil Hitler". 236 00:17:50,140 --> 00:17:51,739 I could just send it in clear... 237 00:17:51,740 --> 00:17:55,739 BEEPING ..H, E, I, and so on. 238 00:17:55,860 --> 00:17:58,619 Obviously people don't want to do that because people are going to read it. 239 00:17:58,620 --> 00:18:01,339 So you have a machine to encode it. 240 00:18:01,340 --> 00:18:05,339 Every day, Enigma was set up in a new way by resetting rotor wheels. 241 00:18:06,780 --> 00:18:09,499 Depending on the day's starting rotor position, 242 00:18:09,500 --> 00:18:13,499 Enigma replaced each letter by another through a labyrinth of switching wheels. 243 00:18:14,980 --> 00:18:18,059 They scrambled the letters in ever-changing combinations. 244 00:18:18,060 --> 00:18:22,059 With every key press, the code changed. 245 00:18:22,820 --> 00:18:26,819 The receiver, on getting the message "SJFX", he would then set the rotors 246 00:18:27,860 --> 00:18:31,619 to the correct starting position and then press S... 247 00:18:31,620 --> 00:18:35,619 J, F, X. 248 00:18:37,300 --> 00:18:40,899 "HEIL". 249 00:18:40,900 --> 00:18:43,939 To put in perspective how difficult it was, 250 00:18:43,940 --> 00:18:47,019 the number of possible combinations you would have to try, 251 00:18:47,020 --> 00:18:51,019 just at random, in order to hit upon the answer by luck with the Enigma machine 252 00:18:51,300 --> 00:18:55,299 was 158 million, million, million. 253 00:18:55,420 --> 00:18:59,259 And compare that with the odds against your winning the Lottery, 254 00:18:59,260 --> 00:19:01,939 which is a mere 14 million to one. 255 00:19:01,940 --> 00:19:05,939 The Germans believed Enigma was unbreakable. 256 00:19:06,740 --> 00:19:09,019 The British thought differently. 257 00:19:09,020 --> 00:19:12,099 Mathematicians such as Turing and his colleagues 258 00:19:12,100 --> 00:19:15,899 convinced the politicians that it was in principle possible 259 00:19:15,900 --> 00:19:19,899 to break the Enigma code. 260 00:19:20,860 --> 00:19:22,539 NEWSREEL: A convoy at sea, 261 00:19:22,540 --> 00:19:26,539 one of the lifelines upon which the United Nations' war effort relies. 262 00:19:27,740 --> 00:19:31,379 The prize for winning the Enigma lottery 263 00:19:31,380 --> 00:19:33,299 would be Britain's survival. 264 00:19:33,300 --> 00:19:35,619 The U-boat wolf packs in the North Atlantic 265 00:19:35,620 --> 00:19:39,619 were sinking convoys every day and severing our lifeline to America. 266 00:19:39,860 --> 00:19:43,859 All U-boat secret communications used Enigma. 267 00:19:46,860 --> 00:19:49,459 Using captured machines and codebooks, 268 00:19:49,460 --> 00:19:53,459 some very clever mathematics, intuitions, and imaginative guesswork, 269 00:19:54,180 --> 00:19:58,179 the code-breakers tried to probe the Enigma system for weaknesses. 270 00:19:59,020 --> 00:20:03,019 And they found them. Human error, repetition of certain phrases 271 00:20:03,580 --> 00:20:07,579 or greetings, such as "heil Hitler", or patterns in weather forecasts, say. 272 00:20:09,780 --> 00:20:13,659 But looking for these needles in the cryptographic haystack 273 00:20:13,660 --> 00:20:17,659 took thousands of human hours. 274 00:20:19,060 --> 00:20:21,859 Turing came up with a brilliant shortcut 275 00:20:21,860 --> 00:20:25,859 in the hunt for the rotor settings. 276 00:20:29,780 --> 00:20:33,059 It was an electromagnetic machine called "the bombe", 277 00:20:33,060 --> 00:20:35,619 and it was Turing's first attempt 278 00:20:35,620 --> 00:20:39,619 to put his idea of a mechanical brain into practice. 279 00:20:40,780 --> 00:20:44,779 The daily task for the code-breakers was to try to work out 280 00:20:45,700 --> 00:20:49,699 the starting position of the three wheels for that day. 281 00:20:51,660 --> 00:20:55,659 Each one of these rotating drums represents one of the three wheels, 282 00:20:56,260 --> 00:20:58,539 and as they spin around, 283 00:20:58,540 --> 00:21:02,139 they are examining each of the possible positions of the wheel 284 00:21:02,140 --> 00:21:05,339 to see whether it makes sense. 285 00:21:05,340 --> 00:21:08,579 Now, the second trick, which was absolutely vital, 286 00:21:08,580 --> 00:21:12,579 was that they made a guess as to what a message might possibly mean. 287 00:21:13,620 --> 00:21:17,619 They knew, for example, that one of the things the Germans often sent 288 00:21:17,940 --> 00:21:21,939 was weather forecasts and they knew the word for weather, which is "wetter", 289 00:21:22,100 --> 00:21:24,659 W-E-T-T-E-R, 290 00:21:24,660 --> 00:21:27,459 and so they were looking for a starting position of the wheels 291 00:21:27,460 --> 00:21:31,459 which made sense on the assumption that the word being sent was "wetter". 292 00:21:33,740 --> 00:21:36,659 They could read any message that was sent by that machine 293 00:21:36,660 --> 00:21:39,979 during that day. 294 00:21:39,980 --> 00:21:43,979 By the second half of 1941, Bletchley Park was reading 295 00:21:43,980 --> 00:21:47,979 most of the signal traffic of the German navy. 296 00:21:48,380 --> 00:21:52,019 Now, the vital North Atlantic convoys could be rerouted 297 00:21:52,020 --> 00:21:54,419 to avoid the U-boat wolf packs, 298 00:21:54,420 --> 00:21:57,739 and vital supplies could get through to beleaguered Britain. 299 00:21:57,740 --> 00:22:01,739 What the U-boat commanders called their "happy time" was at an end. 300 00:22:07,580 --> 00:22:10,499 The bombe wasn't a true computer, 301 00:22:10,500 --> 00:22:14,259 but it laid the foundations for the development of one. 302 00:22:14,260 --> 00:22:17,739 By the end of the war, Turing and his colleagues 303 00:22:17,740 --> 00:22:21,739 had developed another code-breaking machine, Colossus, 304 00:22:22,220 --> 00:22:26,219 which was indeed the world's first digital computer. 305 00:22:26,540 --> 00:22:30,539 Without Alan Turing and the Bletchley Park code-breakers, 306 00:22:30,820 --> 00:22:34,179 Britain might not have survived the Battle of the Atlantic, 307 00:22:34,180 --> 00:22:38,179 and we would not have the computer-driven world we know today. 308 00:22:40,860 --> 00:22:43,179 May 1941. 309 00:22:43,180 --> 00:22:46,299 While Alan Turing and his code-breakers 310 00:22:46,300 --> 00:22:50,099 eavesdropped on the Germans, another British genius, 311 00:22:50,100 --> 00:22:54,099 just 70 miles away, was demonstrating the future. 312 00:22:54,820 --> 00:22:58,819 His name was Frank Whittle, and he had created 313 00:22:58,860 --> 00:23:02,419 a plane that would transform our world. 314 00:23:02,420 --> 00:23:06,419 May 15th 1941, the test flight of Britain's first jet. 315 00:23:08,980 --> 00:23:12,979 At 7.45pm, the Gloster E28 316 00:23:13,380 --> 00:23:17,379 flew low and fast over Cranwell Airfield at 370 miles per hour. 317 00:23:23,060 --> 00:23:25,499 The Air Ministry were so uninterested, 318 00:23:25,500 --> 00:23:27,779 they hadn't even bothered to send a photographer. 319 00:23:27,780 --> 00:23:31,779 Luckily, an amateur cameraman captured it on film. 320 00:23:35,020 --> 00:23:38,619 It come right close up to us and ran down the ground 321 00:23:38,620 --> 00:23:41,779 just like a partridge and took off up in the air 322 00:23:41,780 --> 00:23:45,659 and then disappeared in the clouds. 323 00:23:45,660 --> 00:23:48,779 I downed tools and ran in the house to tell everybody 324 00:23:48,780 --> 00:23:50,619 I'd seen an aeroplane without a propeller. 325 00:23:50,620 --> 00:23:54,339 Course, nobody believed me! 326 00:23:54,340 --> 00:23:58,339 The inventor, Frank Whittle, was a brilliant engineer and RAF pilot. 327 00:24:00,540 --> 00:24:01,859 He is a hero of mine. 328 00:24:01,860 --> 00:24:04,099 And if Whittle had been listened to, 329 00:24:04,100 --> 00:24:08,099 planes like this could have been in action against the Luftwaffe 330 00:24:08,140 --> 00:24:11,179 in the Battle of Britain in 1940. 331 00:24:11,180 --> 00:24:15,179 What fascinates me is why nobody believed the eminently believable. 332 00:24:16,140 --> 00:24:20,139 Frank Whittle, a true genius and one of the greatest inventors ever, 333 00:24:21,420 --> 00:24:25,419 not that anyone in officialdom at the time was bright enough to notice. 334 00:24:26,100 --> 00:24:28,339 He thrust Britain into the jet age 335 00:24:28,340 --> 00:24:31,259 and turned the aviation industry on its head. 336 00:24:31,260 --> 00:24:35,259 All with zero encouragement and quite a bit of opposition from the Government. 337 00:24:38,140 --> 00:24:42,139 Some say that the problem lay in Whittle's working-class background, 338 00:24:42,300 --> 00:24:44,659 others in his single-mindedness. 339 00:24:44,660 --> 00:24:47,659 When he was four, Frank was given a model aeroplane 340 00:24:47,660 --> 00:24:51,659 and decided he wanted to become a pilot. 341 00:24:52,340 --> 00:24:56,259 Aged 16, he scraped into the RAF as an apprentice fitter. 342 00:24:56,260 --> 00:25:00,259 But Whittle learned fast. 343 00:25:01,140 --> 00:25:02,739 Soon he was flying aerobatics 344 00:25:02,740 --> 00:25:05,219 at the famous Hendon air display 345 00:25:05,220 --> 00:25:07,139 and volunteering for dangerous 346 00:25:07,140 --> 00:25:11,139 water ditching trials, even though he couldn't swim. 347 00:25:14,820 --> 00:25:17,899 But he wasn't just brave, he was inspired. 348 00:25:17,900 --> 00:25:19,379 When he was only 21, 349 00:25:19,380 --> 00:25:23,379 in 1928, Frank Whittle wrote a thesis in his exercise book entitled 350 00:25:25,180 --> 00:25:27,579 Future Developments In Aircraft Design, 351 00:25:27,580 --> 00:25:30,899 and here's a copy. 352 00:25:30,900 --> 00:25:33,779 In it, he foresaw the whole future of flight. 353 00:25:33,780 --> 00:25:37,219 He could imagine planes flying at 500 miles an hour, 354 00:25:37,220 --> 00:25:40,099 high up in the stratosphere where the air was too thin 355 00:25:40,100 --> 00:25:42,539 for propellers and piston engines to work. 356 00:25:42,540 --> 00:25:45,699 He envisaged that the turbine had the potential 357 00:25:45,700 --> 00:25:48,379 to be the prime mover for jet propulsion. 358 00:25:48,380 --> 00:25:51,979 Whittle's ideas must have seemed like science fiction or fantasy, 359 00:25:51,980 --> 00:25:55,619 but he had done the mathematical calculations to prove them. 360 00:25:55,620 --> 00:25:59,259 He was awarded full marks for his thesis, 361 00:25:59,260 --> 00:26:01,019 with his professor remarking, 362 00:26:01,020 --> 00:26:03,859 "I couldn't quite follow everything you've written, Whittle, 363 00:26:03,860 --> 00:26:07,219 "but I couldn't find anything wrong with it." 364 00:26:07,220 --> 00:26:08,659 I was thrilled to discover 365 00:26:08,660 --> 00:26:11,779 that there's a film about the invention of the jet engine 366 00:26:11,780 --> 00:26:15,299 in which Frank Whittle, the one with the moustache, plays himself. 367 00:26:15,300 --> 00:26:17,139 Ever patented anything? 368 00:26:17,140 --> 00:26:19,539 Ever patented anything? No, I don't know a thing about it. 369 00:26:19,540 --> 00:26:23,539 I'll tell you what, let's rough out a specification now. 370 00:26:23,740 --> 00:26:25,939 What kind, what do we do? 371 00:26:25,940 --> 00:26:28,299 Well, you make a rather better sketch, 372 00:26:28,300 --> 00:26:30,739 I'll get on with the clever bit, the writing. 373 00:26:30,740 --> 00:26:31,819 OK. 374 00:26:31,820 --> 00:26:35,579 In 1930, still only 22 years old, 375 00:26:35,580 --> 00:26:38,219 Whittle took out this patent for a jet turbine - 376 00:26:38,220 --> 00:26:42,219 a design so simple and so elegant that it takes my breath away. 377 00:26:43,500 --> 00:26:46,819 The injection and burning of fuel heats and expands the air 378 00:26:46,820 --> 00:26:49,059 and gives it enough energy 379 00:26:49,060 --> 00:26:50,379 to drive a turbine... 380 00:26:50,380 --> 00:26:54,379 Whittle's idea was to build an engine with only one moving part 381 00:26:54,940 --> 00:26:58,939 instead of the hundreds of moving parts in conventional piston engines. 382 00:27:07,940 --> 00:27:11,019 This is the legendary Rolls-Royce Merlin engine 383 00:27:11,020 --> 00:27:15,019 that powered the Spitfires and Hurricanes in the Battle of Britain. 384 00:27:16,180 --> 00:27:17,419 Magnificent, yes, 385 00:27:17,420 --> 00:27:21,419 but inefficient and at the limit of what pistons and propellers can do. 386 00:27:24,340 --> 00:27:26,979 Whittle's jet engine had no propeller, 387 00:27:26,980 --> 00:27:28,139 or pistons. 388 00:27:28,140 --> 00:27:32,139 It drove the plane through the air by thrust alone. 389 00:27:32,820 --> 00:27:35,419 It could go higher and faster. 390 00:27:35,420 --> 00:27:39,419 It still has enough energy to give a high-velocity propelling jet. 391 00:27:41,780 --> 00:27:45,619 The Air Ministry was happy with conventional engine technology, 392 00:27:45,620 --> 00:27:49,179 so when Whittle's patent lapsed in 1935, 393 00:27:49,180 --> 00:27:55,459 they wouldn't even pay the 5 to renew it. 394 00:27:55,460 --> 00:27:59,459 But if the British Government weren't interested, other people were. 395 00:28:02,460 --> 00:28:05,819 Whittle's patent quickly found its way into Nazi Germany, 396 00:28:05,820 --> 00:28:08,979 where a young engineer called Hans von Ohain 397 00:28:08,980 --> 00:28:11,859 set about developing his own turbine jet 398 00:28:11,860 --> 00:28:15,859 at the state-of-the-art Heinkel factory in Warnemunde on the Baltic coast. 399 00:28:18,820 --> 00:28:20,819 It would be a race now. 400 00:28:20,820 --> 00:28:24,819 Heinkel and von Ohain versus Whittle and Power Jets Limited, 401 00:28:25,180 --> 00:28:29,179 set up with private backing in a disused foundry in Coventry. 402 00:28:32,340 --> 00:28:36,339 Whittle ran the first engine test in April '37... 403 00:28:37,140 --> 00:28:41,139 ..five months ahead of von Ohain. 404 00:28:41,900 --> 00:28:45,859 But who would fly the first plane? 405 00:28:45,860 --> 00:28:49,859 Answer - Hans von Ohain and the Germans on 27th August 1939 406 00:28:52,100 --> 00:28:56,099 with the Heinkel 178. 407 00:28:56,460 --> 00:28:58,459 But the plane was a dead end. 408 00:28:58,460 --> 00:29:00,219 It could fly for only six minutes 409 00:29:00,220 --> 00:29:02,979 and the engine would have to be completely rebuilt 410 00:29:02,980 --> 00:29:05,579 after only a few flights. 411 00:29:05,580 --> 00:29:09,579 Frank Whittle's engine was a triumph from the start. 412 00:29:16,340 --> 00:29:19,859 And here it is, the first Whittle production jet engine 413 00:29:19,860 --> 00:29:21,619 fitted to the Gloster Meteor. 414 00:29:21,620 --> 00:29:25,619 The air comes in the intake here, and it accelerates the air 415 00:29:25,660 --> 00:29:28,379 and then comes through into these combustion chambers 416 00:29:28,380 --> 00:29:29,899 and the fuel is ignited 417 00:29:29,900 --> 00:29:32,059 and goes down into the turbine chamber, 418 00:29:32,060 --> 00:29:35,779 and the turbine accelerates the air at high jet speed out of the back 419 00:29:35,780 --> 00:29:39,419 and that's what provides the thrust to drive the aeroplane forwards. 420 00:29:39,420 --> 00:29:43,419 Now let's start her up. 421 00:29:52,980 --> 00:29:56,979 The Air Ministry was interested at last, and so was Rolls-Royce. 422 00:29:58,700 --> 00:30:00,459 By July 1944, 423 00:30:00,460 --> 00:30:04,459 Whittle-designed jet engines would be powering RAF Meteor fighters, 424 00:30:04,820 --> 00:30:07,899 defending London against the doodlebug, 425 00:30:07,900 --> 00:30:11,899 the V1 flying bomb. 426 00:30:22,020 --> 00:30:25,659 This is what Frank Whittle had in mind when he wrote that thesis. 427 00:30:25,660 --> 00:30:29,659 A plane that can fly 50,000 feet high at 620 miles an hour. 428 00:30:38,460 --> 00:30:40,339 Sitting here as I am now, 429 00:30:40,340 --> 00:30:44,339 I'm literally less than half a metre from two jets... 430 00:30:45,260 --> 00:30:47,339 ..and the... 431 00:30:47,340 --> 00:30:51,019 extraordinary force of acceleration you get from it 432 00:30:51,020 --> 00:30:55,019 presses you right back into your seat. 433 00:30:56,620 --> 00:30:58,699 Remember, there's only one moving part. 434 00:30:58,700 --> 00:31:02,699 He's an absolute genius, Whittle. 435 00:31:08,940 --> 00:31:12,939 1944 was a crucial year in the war. 436 00:31:13,300 --> 00:31:17,299 The Allies were set to launch one of the greatest invasions 437 00:31:17,500 --> 00:31:20,579 in the history of the world. 438 00:31:20,580 --> 00:31:24,579 Alan Turing's code-breakers had continued to crack the German codes, 439 00:31:25,460 --> 00:31:28,299 reading secret messages 440 00:31:28,300 --> 00:31:32,299 and providing reassurance that D-Day would come as a surprise to Hitler. 441 00:31:33,340 --> 00:31:35,819 The invasion would be a success, 442 00:31:35,820 --> 00:31:39,179 but the casualties were appalling. 443 00:31:39,180 --> 00:31:43,179 But help was at hand for the injured. 444 00:31:43,820 --> 00:31:47,819 The story of the discovery of penicillin has passed into legend, 445 00:31:48,380 --> 00:31:52,379 but like most legends, the truth is very different. 446 00:31:58,900 --> 00:32:01,699 I'm a biologist and I'm fascinated 447 00:32:01,700 --> 00:32:05,619 by Alexander Fleming and his discovery of penicillin. 448 00:32:05,620 --> 00:32:09,619 This is St Mary's Hospital near Paddington Station in London. 449 00:32:10,060 --> 00:32:11,739 Fleming came back here 450 00:32:11,740 --> 00:32:14,419 after serving as a doctor in the First World War, 451 00:32:14,420 --> 00:32:18,419 determined to find a way to fight infectious diseases. 452 00:32:19,020 --> 00:32:22,499 There is a real story to be told here. 453 00:32:22,500 --> 00:32:26,499 In September 1928, a mould spore came into this room, 454 00:32:28,100 --> 00:32:32,099 nobody knows from where - maybe through the window, maybe through the door, 455 00:32:32,220 --> 00:32:36,219 maybe somebody walked it up on their shoes. 456 00:32:36,660 --> 00:32:40,099 But wherever it came from, it settled on a glass plate 457 00:32:40,100 --> 00:32:41,659 like this one. 458 00:32:41,660 --> 00:32:44,779 A glass dish that had been left unwashed 459 00:32:44,780 --> 00:32:48,139 and which contained jelly and nutrients. 460 00:32:48,140 --> 00:32:50,579 Alexander Fleming was a great scientist 461 00:32:50,580 --> 00:32:52,899 but he wasn't the tidiest of men 462 00:32:52,900 --> 00:32:55,579 and he had left some of these plates lying around 463 00:32:55,580 --> 00:32:59,179 when he went on holiday. 464 00:32:59,180 --> 00:33:01,139 When Fleming came back, 465 00:33:01,140 --> 00:33:05,139 there were a lot of staphylococcus bacteria growing on the plate. 466 00:33:05,220 --> 00:33:09,059 That was normal, they are found all over the place. 467 00:33:09,060 --> 00:33:13,059 But what wasn't normal was that where this unknown mould was growing, 468 00:33:14,260 --> 00:33:18,259 he noticed it had stopped the growth of the bacteria around it. 469 00:33:20,660 --> 00:33:22,499 And what Fleming thought 470 00:33:22,500 --> 00:33:26,499 was that maybe this mould is making a substance that kills the bacteria. 471 00:33:28,260 --> 00:33:31,539 This was going to change the course of history. 472 00:33:31,540 --> 00:33:35,539 This was where the era of antibiotics began. 473 00:33:38,100 --> 00:33:41,539 So what was the genius of Alexander Fleming? 474 00:33:41,540 --> 00:33:45,539 Well, partly it's as Pasteur said - "Chance favours the prepared mind." 475 00:33:47,900 --> 00:33:51,339 Fleming's mind had been prepared during the First World War. 476 00:33:51,340 --> 00:33:55,339 It had been prepared seeing people dying of infections. 477 00:33:55,340 --> 00:33:57,179 So during the 1920s, 478 00:33:57,180 --> 00:33:59,579 Alexander Fleming had been looking for ways 479 00:33:59,580 --> 00:34:01,779 to inhibit the growth of bacteria. 480 00:34:01,780 --> 00:34:05,779 And when chance brought that mould spore onto his plate 481 00:34:06,620 --> 00:34:10,619 his mind was already prepared to think about its significance 482 00:34:10,700 --> 00:34:14,299 and to see where it might lead. 483 00:34:14,300 --> 00:34:18,299 The green mould growing on that plate was penicillin. 484 00:34:19,220 --> 00:34:22,699 And what Fleming wanted to do was to see whether it was really making a substance 485 00:34:22,700 --> 00:34:26,699 that would kill bacteria that infected human beings. 486 00:34:27,780 --> 00:34:30,819 He filtered off the liquid in which the mould had been growing 487 00:34:30,820 --> 00:34:34,419 and then used it to treat a wide variety of bacteria 488 00:34:34,420 --> 00:34:36,819 that infected human beings, 489 00:34:36,820 --> 00:34:39,819 and what he showed was that the filtered liquid 490 00:34:39,820 --> 00:34:43,499 could kill many of these bacteria. 491 00:34:43,500 --> 00:34:47,459 It could kill the bacteria that caused pneumonia, diphtheria, 492 00:34:47,460 --> 00:34:48,899 syphilis, gonorrhoea. 493 00:34:48,900 --> 00:34:50,899 So what he had in his hands 494 00:34:50,900 --> 00:34:54,899 was a possible brand-new way of treating these deadly diseases. 495 00:34:58,100 --> 00:35:01,979 But although penicillin looked like it might be a magic bullet, 496 00:35:01,980 --> 00:35:05,979 Fleming couldn't produce enough of it to test on animals, let alone humans. 497 00:35:06,780 --> 00:35:09,859 And his laboratory experiments suggested 498 00:35:09,860 --> 00:35:12,219 it wouldn't work in living systems anyway. 499 00:35:12,220 --> 00:35:15,899 So Fleming sent samples of it to various labs around the world, 500 00:35:15,900 --> 00:35:18,739 and he moved on to other research. 501 00:35:18,740 --> 00:35:22,739 And there the story of penicillin rested, for more than ten years. 502 00:35:26,860 --> 00:35:29,979 It took an Australian, Howard Florey, 503 00:35:29,980 --> 00:35:33,979 to take up penicillin research again and crack the problem of production. 504 00:35:35,940 --> 00:35:39,459 This is where, in a lab in wartime Britain, 505 00:35:39,460 --> 00:35:41,539 with all its shortages and rationing, 506 00:35:41,540 --> 00:35:45,459 Florey and his colleagues managed to do what Fleming could not - 507 00:35:45,460 --> 00:35:48,939 grow penicillin in enough quantity 508 00:35:48,940 --> 00:35:52,099 and extract it for live testing. 509 00:35:52,100 --> 00:35:56,099 When they had enough penicillin, they could test it on mice. 510 00:35:56,620 --> 00:36:00,299 They took eight mice and infected them with bacteria. 511 00:36:00,300 --> 00:36:04,299 Four they gave penicillin and four they did not. 512 00:36:04,300 --> 00:36:08,299 Within a day, the four that did not get penicillin were dead. 513 00:36:08,340 --> 00:36:11,499 The four that got penicillin were perfectly alive 514 00:36:11,500 --> 00:36:13,339 and running around their cages. 515 00:36:13,340 --> 00:36:16,299 Penicillin worked in mice, and if it worked in mice, 516 00:36:16,300 --> 00:36:20,299 it probably would work in humans. 517 00:36:20,620 --> 00:36:24,259 But a human is 3,000 times heavier than a mouse, 518 00:36:24,260 --> 00:36:28,259 and that's how much more penicillin they needed before they could treat a human. 519 00:36:31,060 --> 00:36:35,059 They grew it in hospital bedpans, and when they ran out of them, 520 00:36:35,220 --> 00:36:39,219 in ceramic pots. 521 00:36:39,900 --> 00:36:42,739 This is the Radcliffe Infirmary. 522 00:36:42,740 --> 00:36:44,859 This hospital is closed now, 523 00:36:44,860 --> 00:36:48,419 but it was the place where Florey and his colleagues first tested penicillin 524 00:36:48,420 --> 00:36:52,419 on a human patient in the hope of curing him. 525 00:36:52,460 --> 00:36:54,059 There was a policeman, 526 00:36:54,060 --> 00:36:55,939 Albert Alexander. 527 00:36:55,940 --> 00:36:59,939 He'd scratched his face with a rose thorn and it had become infected. 528 00:37:01,980 --> 00:37:04,139 It was a terrible infection. 529 00:37:04,140 --> 00:37:06,619 It was eating away at his face. 530 00:37:06,620 --> 00:37:08,699 He had already lost an eye. 531 00:37:08,700 --> 00:37:12,699 Florey and his colleagues had just enough penicillin to start treating him. 532 00:37:14,820 --> 00:37:17,179 At first, the penicillin really helped. 533 00:37:17,180 --> 00:37:19,459 But then they ran out. 534 00:37:19,460 --> 00:37:21,619 They tried extracting it from his urine, 535 00:37:21,620 --> 00:37:25,219 purifying it and then giving it back to him. 536 00:37:25,220 --> 00:37:27,459 But there wasn't enough. 537 00:37:27,460 --> 00:37:29,819 After five days, he began to relapse, 538 00:37:29,820 --> 00:37:32,419 he got worse, he went on to die. 539 00:37:32,420 --> 00:37:35,699 But the proof of principle had been established. 540 00:37:35,700 --> 00:37:39,699 Penicillin had helped him, and if they could simply make more, 541 00:37:39,820 --> 00:37:43,819 then they had a wonder drug on their hands. 542 00:37:50,220 --> 00:37:54,059 But it was 1941, the Blitz was raging 543 00:37:54,060 --> 00:37:57,379 in London and the great industrial cities of Britain, 544 00:37:57,380 --> 00:38:01,379 and mass production of a new and untried drug was a low priority 545 00:38:02,140 --> 00:38:05,419 for British drug companies. 546 00:38:05,420 --> 00:38:09,419 So Florey and his colleagues took penicillin to America 547 00:38:09,420 --> 00:38:12,779 where they found a can-do attitude as well as the money. 548 00:38:12,780 --> 00:38:15,819 NEWSREEL: Through mass production methods, American is increasing 549 00:38:15,820 --> 00:38:19,819 its output of penicillin, a new drug that affects... 550 00:38:20,860 --> 00:38:24,219 And so it was that by D-Day, 551 00:38:24,220 --> 00:38:26,659 6th June 1944, 552 00:38:26,660 --> 00:38:29,059 there was enough penicillin 553 00:38:29,060 --> 00:38:30,499 to treat every Allied soldier 554 00:38:30,500 --> 00:38:34,499 wounded in the invasion of Normandy and the drive to Berlin. 555 00:38:40,700 --> 00:38:43,059 Like many great discoveries, 556 00:38:43,060 --> 00:38:47,059 penicillin was the work of many, not just one. 557 00:38:47,140 --> 00:38:51,139 The same is true of one of the greatest discoveries in physics - 558 00:38:51,540 --> 00:38:54,059 how to split the atom. 559 00:38:54,060 --> 00:38:58,059 It took three generations of British scientists to crack this problem, 560 00:38:59,140 --> 00:39:03,139 and when they did, it led to the creation of the bombs 561 00:39:03,620 --> 00:39:07,619 that helped end the war but also gave mankind a new and terrifying power. 562 00:39:09,300 --> 00:39:12,739 STEPHEN HAWKING: August, 1945. 563 00:39:12,740 --> 00:39:16,739 The Allied bombs on Hiroshima and Nagasaki brought the Second World 564 00:39:17,860 --> 00:39:20,099 War, at last, towards its end. 565 00:39:20,100 --> 00:39:22,979 The atomic bomb was the culmination 566 00:39:22,980 --> 00:39:26,979 of some of the most important discoveries in science, 567 00:39:27,460 --> 00:39:31,019 the brilliant insights and experiments which laid bare 568 00:39:31,020 --> 00:39:35,019 the structure of the atom. 569 00:39:35,580 --> 00:39:39,259 It is a story which owes much to three generations 570 00:39:39,260 --> 00:39:41,059 of British scientists 571 00:39:41,060 --> 00:39:45,059 at the Cavendish Laboratory in Cambridge. 572 00:39:45,420 --> 00:39:49,419 In 1899, JJ Thomson discovered the electron. 573 00:39:50,340 --> 00:39:52,739 21 years later, 574 00:39:52,740 --> 00:39:56,739 his student Ernest Rutherford identified the proton. 575 00:39:58,020 --> 00:40:02,019 In 1932, Rutherford handed the torch down to James Chadwick, 576 00:40:03,380 --> 00:40:05,699 who identified the neutron. 577 00:40:05,700 --> 00:40:09,699 And in the same year, Cockcroft and Walton built a linear accelerator 578 00:40:10,700 --> 00:40:12,979 and split the atomic nucleus 579 00:40:12,980 --> 00:40:16,979 which their forbears had taken 33 years to put together. 580 00:40:18,700 --> 00:40:22,139 The achievements of all these men are immense. 581 00:40:22,140 --> 00:40:25,779 But many physicists reserve a special admiration 582 00:40:25,780 --> 00:40:29,259 for the work of a man whose name is less well known. 583 00:40:29,260 --> 00:40:31,539 Paul Dirac. 584 00:40:31,540 --> 00:40:35,539 He uncovered one of the great secrets of the universe. 585 00:40:38,300 --> 00:40:41,659 KATHY SYKES: Now, Paul Dirac isn't exactly a household name, 586 00:40:41,660 --> 00:40:44,019 but I think he should be. 587 00:40:44,020 --> 00:40:47,579 Dirac may not sound British, but British he was, 588 00:40:47,580 --> 00:40:51,019 and a physicist's physicist. 589 00:40:51,020 --> 00:40:55,019 He was obsessed by beauty, simplicity and mathematics. 590 00:40:56,940 --> 00:41:00,819 He once said that when God created the world, 591 00:41:00,820 --> 00:41:02,979 he used beautiful mathematics. 592 00:41:02,980 --> 00:41:06,939 Now, when he said, "God", he probably meant Nature. 593 00:41:06,940 --> 00:41:10,939 He was a confirmed atheist. 594 00:41:10,940 --> 00:41:14,739 Dirac was certainly a most unusual man. 595 00:41:14,740 --> 00:41:18,739 He once said, "I never knew love or affection as a child," 596 00:41:18,940 --> 00:41:22,859 and there are many stories and anecdotes about his strangeness. 597 00:41:22,860 --> 00:41:26,819 Dirac was once having a serious argument with his wife 598 00:41:26,820 --> 00:41:30,819 and she eventually said, "And what would you do if I left you?" 599 00:41:31,020 --> 00:41:34,099 He thought for a while and then he said, 600 00:41:34,100 --> 00:41:37,179 "I'd say, "Goodbye, dear."" 601 00:41:37,180 --> 00:41:41,179 People have suggested he might have been autistic. 602 00:41:41,780 --> 00:41:44,779 If he was, perhaps it helped with the clarity 603 00:41:44,780 --> 00:41:48,779 and concentration he brought to physics. 604 00:41:50,580 --> 00:41:54,139 Dirac worked here at Cambridge at the Cavendish Laboratory, 605 00:41:54,140 --> 00:41:58,139 alongside nuclear physicists like Rutherford and Chadwick. 606 00:41:59,180 --> 00:42:03,179 And what he did transformed the work of many physicists to follow. 607 00:42:03,940 --> 00:42:07,739 In 1928, Paul Dirac pulled off 608 00:42:07,740 --> 00:42:11,259 one of the greatest mathematical feats in the history of science. 609 00:42:11,260 --> 00:42:13,979 The Dirac equation. 610 00:42:13,980 --> 00:42:16,579 Think of this less as an equation 611 00:42:16,580 --> 00:42:20,579 and more as a key to understanding the innermost workings 612 00:42:20,660 --> 00:42:23,139 of the universe. 613 00:42:23,140 --> 00:42:25,659 Dirac had worked out what electrons do, 614 00:42:25,660 --> 00:42:28,819 and it looks like this. 615 00:42:28,820 --> 00:42:32,819 This equation brings together two of the great theories in physics - 616 00:42:33,500 --> 00:42:37,499 quantum mechanics, which describes the world of the very small, 617 00:42:37,500 --> 00:42:39,179 things on the atomic scale, 618 00:42:39,180 --> 00:42:43,179 and also Einstein's special theory of relativity, 619 00:42:43,300 --> 00:42:45,579 which describes the world of the very fast, 620 00:42:45,580 --> 00:42:49,579 things travelling close to the speed of light. 621 00:42:50,580 --> 00:42:54,579 This equation won Dirac a Nobel Prize in 1933. 622 00:42:55,420 --> 00:42:59,419 To begin with, he didn't want it because he hated publicity. 623 00:43:00,300 --> 00:43:03,059 But the story goes that Ernest Rutherford, 624 00:43:03,060 --> 00:43:05,899 the great atomic scientist who'd won one in 1908, 625 00:43:05,900 --> 00:43:09,899 persuaded Dirac that the publicity would be much worse 626 00:43:09,900 --> 00:43:11,699 if he turned the prize down. 627 00:43:11,700 --> 00:43:13,739 So he agreed. 628 00:43:13,740 --> 00:43:17,739 The Dirac equation also included a prediction of something bizarre 629 00:43:19,140 --> 00:43:21,939 that had never even been observed, 630 00:43:21,940 --> 00:43:25,099 so no-one believed or knew it existed. 631 00:43:25,100 --> 00:43:29,099 But Dirac's mathematics said it had to exist, 632 00:43:29,140 --> 00:43:33,139 and that crazy something was antimatter. 633 00:43:33,940 --> 00:43:37,179 Scientists believe that when the universe was created, 634 00:43:37,180 --> 00:43:41,179 the big bang made almost as much antimatter as it did matter. 635 00:43:43,820 --> 00:43:47,179 The world as we know it is made of matter, 636 00:43:47,180 --> 00:43:49,979 so where did all the antimatter go? 637 00:43:49,980 --> 00:43:53,619 It's one of the great unanswered questions of science. 638 00:43:53,620 --> 00:43:55,699 If you could get some antimatter 639 00:43:55,700 --> 00:43:59,099 and were to bring it together with ordinary matter, 640 00:43:59,100 --> 00:44:03,099 a lot of energy would be released. 641 00:44:04,580 --> 00:44:08,179 Just as well, then, that the scientists at CERN 642 00:44:08,180 --> 00:44:12,179 have only been able to make ten billionth of a gram in 30 years. 643 00:44:16,220 --> 00:44:20,219 Paul Dirac was one of the greatest nuclear theoretical physicists 644 00:44:21,260 --> 00:44:23,259 since Isaac Newton. 645 00:44:23,260 --> 00:44:26,699 His equation governs most of physics 646 00:44:26,700 --> 00:44:28,379 and the whole of chemistry. 647 00:44:28,380 --> 00:44:32,379 If he could have patented it, he would have been very rich. 648 00:44:33,060 --> 00:44:37,059 Every television set and computer would have paid him royalties. 649 00:44:42,820 --> 00:44:46,579 PAUL NURSE: In 1945, Alexander Fleming and Howard Florey, 650 00:44:46,580 --> 00:44:50,099 together with Florey's colleague Ernst Chain, 651 00:44:50,100 --> 00:44:54,099 shared the Nobel Prize for their discovery of penicillin. 652 00:44:55,020 --> 00:44:59,019 JAMES DYSON: Frank Whittle went to live in the United States, 653 00:44:59,660 --> 00:45:01,019 where he became friends 654 00:45:01,020 --> 00:45:05,019 with his old German rival, Hans von Ohain. 655 00:45:05,500 --> 00:45:07,819 Many years later, von Ohain remarked 656 00:45:07,820 --> 00:45:11,099 that if officials had backed Whittle, World War Two might 657 00:45:11,100 --> 00:45:12,379 never have happened. 658 00:45:12,380 --> 00:45:16,379 Hitler would have doubted the Luftwaffe's ability to win. 659 00:45:17,220 --> 00:45:19,059 JIM AL-KHALILI: After the war, 660 00:45:19,060 --> 00:45:21,899 Britain's radar pioneer went to live in Canada. 661 00:45:21,900 --> 00:45:25,899 In the 1960s, the then elderly Watson-Watt 662 00:45:26,140 --> 00:45:30,139 was stopped by a policeman with a radar gun and given a ticket. 663 00:45:30,660 --> 00:45:32,579 Watson-Watt said to the policeman, 664 00:45:32,580 --> 00:45:34,979 "If I'd known what you were going to do with it, 665 00:45:34,980 --> 00:45:38,139 "I'd never have invented it." 666 00:45:38,140 --> 00:45:40,219 RICHARD DAWKINS: And what of Alan Turing? 667 00:45:40,220 --> 00:45:43,539 Soon after the war, he went to Manchester University, 668 00:45:43,540 --> 00:45:47,259 where he pioneered the development of computer theory and programming 669 00:45:47,260 --> 00:45:51,259 until his mysterious death in 1954. 670 00:45:51,820 --> 00:45:55,819 Was the explanation suicide, accident, or assassination? 671 00:45:57,260 --> 00:45:59,539 Surely by far the most plausible 672 00:45:59,540 --> 00:46:03,059 is the official suicide verdict of the coroner. 673 00:46:03,060 --> 00:46:05,979 Turing had every reason to be unhappy. 674 00:46:05,980 --> 00:46:07,619 In 1952, 675 00:46:07,620 --> 00:46:10,539 he had been convicted of homosexual behaviour. 676 00:46:10,540 --> 00:46:14,539 He'd been offered a choice between prison and chemical castration 677 00:46:15,300 --> 00:46:18,979 by hormone injections which caused his breasts to grow. 678 00:46:18,980 --> 00:46:21,579 No wonder he was depressed. 679 00:46:21,580 --> 00:46:25,579 Whatever the truth, Turing's death at the age of only 41 680 00:46:25,780 --> 00:46:29,779 was surely one of the great tragedies in the history of science. 681 00:46:29,780 --> 00:46:32,539 If anybody could be said to have invented the future, 682 00:46:32,540 --> 00:46:33,579 it was Alan Turing, 683 00:46:33,580 --> 00:46:37,579 but he didn't live to see what he had done. 684 00:46:46,300 --> 00:46:48,139 Next time... 685 00:46:48,140 --> 00:46:50,739 For all the achievements of those who had gone before, 686 00:46:50,740 --> 00:46:53,499 two big questions remained. 687 00:46:53,500 --> 00:46:56,659 How did the universe begin? 688 00:46:56,660 --> 00:47:00,019 And what is the secret of life? 689 00:47:00,020 --> 00:47:02,259 Why are you so obsessed with God? 690 00:47:02,260 --> 00:47:06,259 Well, um...