1 00:01:14,274 --> 00:01:15,741 This submarine is setting out 2 00:01:15,875 --> 00:01:19,572 to explore the floor of the Atlantic Ocean. 3 00:01:22,315 --> 00:01:24,408 Until recently What lay at the bottom 4 00:01:24,551 --> 00:01:27,179 Was a complete mystery. 5 00:01:28,721 --> 00:01:31,554 But there, under thousands of meters of Water, 6 00:01:31,691 --> 00:01:33,420 lies the key to hoW the surface 7 00:01:33,560 --> 00:01:36,324 of our planet Was created. 8 00:01:44,971 --> 00:01:47,838 The story of hoW the sea floor gave up its secret 9 00:01:47,974 --> 00:01:50,670 began nearly 100 years ago - 10 00:01:51,744 --> 00:01:53,712 on dry land. 11 00:01:55,715 --> 00:01:57,114 The first clues came from 12 00:01:57,250 --> 00:02:00,651 looking at the shape of the continents. 13 00:02:02,355 --> 00:02:05,256 Ever since the first accurate maps Were made 14 00:02:05,391 --> 00:02:07,655 it had been noticed that if you Were to push 15 00:02:07,794 --> 00:02:09,694 the coast of South Africa here 16 00:02:09,829 --> 00:02:11,763 up against the coast of South America 17 00:02:11,898 --> 00:02:14,332 7,000 kilometres aWay 18 00:02:14,467 --> 00:02:16,992 they'd fit snugly together. 19 00:02:18,304 --> 00:02:21,432 At the turn of the the century a young German scientist, 20 00:02:21,574 --> 00:02:23,098 Alfred Wegener, 21 00:02:23,243 --> 00:02:27,145 decided to find out Whether this fit Was just coincidence 22 00:02:27,280 --> 00:02:28,611 or Whether the tWo continents 23 00:02:28,748 --> 00:02:31,273 had once been connected. 24 00:02:33,820 --> 00:02:35,344 Wegener needed solid evidence 25 00:02:35,488 --> 00:02:38,787 to support this extraordinary idea. 26 00:02:38,925 --> 00:02:41,120 He began by comparing the rocks 27 00:02:41,261 --> 00:02:44,253 on either side of the Atlantic Ocean. 28 00:02:45,832 --> 00:02:48,665 Table Mountain is one of the most familiar landmarks 29 00:02:48,801 --> 00:02:49,995 in South Africa 30 00:02:50,136 --> 00:02:52,263 and it's the field area of geologist 31 00:02:52,405 --> 00:02:54,896 Maarten de Wit. 32 00:02:55,041 --> 00:02:56,770 What's great about being on top 33 00:02:56,910 --> 00:02:57,899 of Table Mountain here 34 00:02:58,044 --> 00:03:00,069 is that We have a fantastic vantage point 35 00:03:00,213 --> 00:03:02,647 from Which to understand some of the evidence 36 00:03:02,782 --> 00:03:05,842 that Wegener put together 37 00:03:05,985 --> 00:03:07,009 and here We are 38 00:03:07,153 --> 00:03:08,950 at the very Western extremity 39 00:03:09,088 --> 00:03:11,750 of the Cape mountains that stretch 40 00:03:11,891 --> 00:03:13,950 to the east of us 2,000 kilometres 41 00:03:14,093 --> 00:03:17,426 but here it is abruptly truncated 42 00:03:17,564 --> 00:03:19,225 by the Atlantic Ocean, 43 00:03:19,365 --> 00:03:21,196 and the next time We see it again 44 00:03:21,334 --> 00:03:24,963 is across that vast stretch of ocean 45 00:03:25,104 --> 00:03:27,698 in Argentina in South America. 46 00:03:28,408 --> 00:03:29,397 You go to South America 47 00:03:29,542 --> 00:03:31,100 and you see exactly the same thing, 48 00:03:31,244 --> 00:03:33,576 same structure, same rocks, everything. 49 00:03:33,713 --> 00:03:36,181 The Cape fault belt stops here, 50 00:03:36,316 --> 00:03:38,147 starts again south of Buenos Aires. 51 00:03:38,284 --> 00:03:39,842 Those tWo bits of information 52 00:03:39,986 --> 00:03:43,387 essentially alloWs you to close that Atlantic Ocean. 53 00:03:43,523 --> 00:03:45,184 And When you close that Atlantic Ocean, 54 00:03:45,325 --> 00:03:46,917 those tWo pieces of mountain belt 55 00:03:47,060 --> 00:03:50,120 formulate one huge long mountain chain. 56 00:03:55,435 --> 00:03:56,993 More evidence that the continents 57 00:03:57,136 --> 00:03:58,467 had once been joined 58 00:03:58,605 --> 00:04:01,665 came from looking at the fossil record. 59 00:04:02,809 --> 00:04:05,039 The fossil of one particular plant 60 00:04:05,178 --> 00:04:07,476 caught Wegener's attention. 61 00:04:08,615 --> 00:04:10,310 This is glossopteris. 62 00:04:10,450 --> 00:04:12,850 lt's a kind of fir tree, early fir tree. 63 00:04:12,986 --> 00:04:14,817 You can see hoW very exceptionally Well 64 00:04:14,954 --> 00:04:17,582 some of these fossils are preserved. 65 00:04:17,724 --> 00:04:19,954 lt's Widely found not only here 66 00:04:20,093 --> 00:04:22,721 but at that time Was also found in, 67 00:04:22,862 --> 00:04:25,456 in places like lndia, Madagascar and Australia 68 00:04:25,598 --> 00:04:28,226 and later on even in Antarctica, 69 00:04:28,368 --> 00:04:29,335 South America, 70 00:04:29,469 --> 00:04:31,403 so they Were very Widely distributed 71 00:04:31,537 --> 00:04:33,061 in these 300 million-year-old rocks 72 00:04:33,206 --> 00:04:36,175 and Wegener used that idea to argue 73 00:04:36,309 --> 00:04:37,640 What Would have been very difficult 74 00:04:37,777 --> 00:04:39,267 for these fossils to float 75 00:04:39,412 --> 00:04:40,879 across huge expanses of ocean. 76 00:04:41,014 --> 00:04:42,106 Rather than that he, 77 00:04:42,248 --> 00:04:44,216 he argued it Would be easier to explain 78 00:04:44,350 --> 00:04:45,510 if all these continents Were together 79 00:04:45,652 --> 00:04:47,916 as one huge land mass. 80 00:04:48,888 --> 00:04:51,857 As they scoured the rocks of far-flung continents 81 00:04:51,991 --> 00:04:54,186 geologists found more and more examples 82 00:04:54,327 --> 00:04:56,227 of plants and animal fossils 83 00:04:56,362 --> 00:05:00,128 that looked like the scattered pieces of a jigsaW puzzle. 84 00:05:00,266 --> 00:05:02,496 Wegener collected as much of this evidence 85 00:05:02,635 --> 00:05:06,002 as he could from around the globe. 86 00:05:09,575 --> 00:05:11,236 When he put the pieces together 87 00:05:11,377 --> 00:05:14,835 he Was forced to the astonishing conclusion; 88 00:05:14,981 --> 00:05:16,448 all the dry land on the planet 89 00:05:16,582 --> 00:05:19,312 must once have been part of a single land mass, 90 00:05:19,452 --> 00:05:23,684 a super-continent he named Pangea. 91 00:05:25,558 --> 00:05:27,753 He suggested that over millions of years, 92 00:05:27,894 --> 00:05:29,987 Pangea split apart. 93 00:05:30,129 --> 00:05:33,565 NeW oceans opened up Where land had once existed. 94 00:05:33,700 --> 00:05:37,227 He called this idea continental drift. 95 00:05:41,307 --> 00:05:45,038 Unfortunately not many people took to the idea. 96 00:05:45,178 --> 00:05:47,612 The trouble Was that Wegener couldn't explain 97 00:05:47,747 --> 00:05:49,908 hoW the gigantic blocks of the continents 98 00:05:50,049 --> 00:05:53,780 could sail through the solid rock of the ocean floor 99 00:05:53,920 --> 00:05:56,411 and Without a plausible mechanism behind it 100 00:05:56,556 --> 00:05:59,719 most people ignored continental drift. 101 00:06:00,493 --> 00:06:01,983 And it remained ignored, 102 00:06:02,128 --> 00:06:04,426 until neW evidence began to emerge 103 00:06:04,564 --> 00:06:07,897 from exploration of the seas. 104 00:06:25,985 --> 00:06:27,179 This is the maiden voyage 105 00:06:27,320 --> 00:06:30,050 of the research ship Atlantis. 106 00:06:30,189 --> 00:06:33,818 lts destination is the middle of the Atlantic Ocean. 107 00:06:33,960 --> 00:06:35,450 On board is a team of scientists 108 00:06:35,595 --> 00:06:37,654 intent on unravelling the secrets 109 00:06:37,797 --> 00:06:39,424 hidden beneath the Water. 110 00:06:39,565 --> 00:06:43,262 Among them is marine geologist, Joe Cann. 111 00:06:43,936 --> 00:06:45,801 Wegener's ideas Were very controversial 112 00:06:45,938 --> 00:06:46,666 When they first came out 113 00:06:46,806 --> 00:06:48,899 and a lot of people dismissed them. 114 00:06:49,041 --> 00:06:50,099 They kneW there had to be Ways 115 00:06:50,243 --> 00:06:52,336 of getting animals and plants 116 00:06:52,478 --> 00:06:54,002 from one continent to another, 117 00:06:54,147 --> 00:06:56,012 because you had these astonishing similarities, 118 00:06:56,149 --> 00:06:59,175 especially in the Southern Hemisphere. 119 00:06:59,318 --> 00:07:00,546 But they couldn't bring themselves to think 120 00:07:00,686 --> 00:07:01,812 that the continents Were drifting. 121 00:07:01,954 --> 00:07:03,888 lnstead, there Was a very strong feeling 122 00:07:04,023 --> 00:07:08,756 that the earth Was heaving in some periodic Way. 123 00:07:08,895 --> 00:07:13,161 That there Were mountain belts rose and fell. 124 00:07:13,299 --> 00:07:15,324 And that pulsing idea led to people thinking 125 00:07:15,468 --> 00:07:17,868 that the ocean floor might rise, 126 00:07:18,004 --> 00:07:19,972 to alloW the animals to Wander across, 127 00:07:20,106 --> 00:07:22,574 and sink again. 128 00:07:22,708 --> 00:07:24,403 An undulation of the ocean floor 129 00:07:24,544 --> 00:07:26,637 from time to time. 130 00:07:26,779 --> 00:07:28,679 lt seems very implausible noW, 131 00:07:28,815 --> 00:07:31,648 but that's hoW they felt about it. 132 00:07:31,784 --> 00:07:33,411 And that meant, of course, that the ocean floor 133 00:07:33,553 --> 00:07:35,646 had to be the same as the continental crust. 134 00:07:35,788 --> 00:07:37,278 lt had to look the same 135 00:07:37,423 --> 00:07:38,720 and you'd expect the same sorts of rocks, 136 00:07:38,858 --> 00:07:41,759 the same sort of materials to make it up. 137 00:07:42,695 --> 00:07:44,185 But of course nobody kneW for sure 138 00:07:44,330 --> 00:07:45,729 What the ocean floor Was made of 139 00:07:45,865 --> 00:07:47,992 because they couldn't see it. 140 00:07:48,134 --> 00:07:50,034 lt took a change in World politics 141 00:07:50,169 --> 00:07:54,037 to reveal the first hints of What really lay beloW. 142 00:07:57,610 --> 00:07:58,804 And aWay she goes. 143 00:07:58,945 --> 00:07:59,775 And in a matter of months... 144 00:07:59,912 --> 00:08:01,140 During the Cold War 145 00:08:01,280 --> 00:08:03,407 submarine Warfare became vitally important. 146 00:08:03,549 --> 00:08:04,379 ...and a number of submarines 147 00:08:04,517 --> 00:08:05,950 are named after statesmen and military... 148 00:08:06,085 --> 00:08:07,484 Nuclear submarines had to be able to 149 00:08:07,620 --> 00:08:09,713 navigate the World's oceans safely. 150 00:08:09,856 --> 00:08:11,687 So sub-mariners needed to be sure 151 00:08:11,824 --> 00:08:14,292 of the depth of the sea floor. 152 00:08:16,162 --> 00:08:18,096 Flush With navy funding, 153 00:08:18,231 --> 00:08:20,222 scientists set out to map the ocean floor 154 00:08:20,366 --> 00:08:22,596 in unprecedented detail. 155 00:08:22,735 --> 00:08:25,397 Their tool Was the echo sounder. 156 00:08:25,905 --> 00:08:27,668 Ships sent out pulses of sound 157 00:08:27,807 --> 00:08:29,069 Which travelled to the sea floor 158 00:08:29,208 --> 00:08:31,642 and then bounced back up again. 159 00:08:35,948 --> 00:08:38,576 The time taken for each ping to make the journey 160 00:08:38,718 --> 00:08:41,619 gave the depth of the Water at that point. 161 00:08:45,191 --> 00:08:46,886 We've basically been using the same types 162 00:08:47,026 --> 00:08:48,516 of precision depth recorders 163 00:08:48,661 --> 00:08:51,824 since the end of the Second World War. 164 00:08:52,331 --> 00:08:53,491 As you can see on this, 165 00:08:53,633 --> 00:08:56,761 on this record from, from the 1950s, 166 00:08:56,903 --> 00:09:00,430 basically you can see that the bottom 167 00:09:00,573 --> 00:09:03,064 is a very fine trace here, 168 00:09:03,209 --> 00:09:04,836 very strong fine trace. 169 00:09:04,977 --> 00:09:06,035 But there are also places 170 00:09:06,178 --> 00:09:09,670 Where the echo sounder record gets very, very confused 171 00:09:09,815 --> 00:09:12,045 and in those areas you have to be very careful 172 00:09:12,184 --> 00:09:13,845 to interpret them correctly. 173 00:09:13,986 --> 00:09:16,546 One of the first people to do this 174 00:09:16,689 --> 00:09:17,951 and Who Was an expert at 175 00:09:18,090 --> 00:09:20,524 it Was Bruce Heezen and his colleague Marie Tharp. 176 00:09:20,660 --> 00:09:23,185 And they Were able to take these echo grams 177 00:09:23,329 --> 00:09:25,627 and make maps from them 178 00:09:25,765 --> 00:09:27,926 that alloWed us to understand 179 00:09:28,067 --> 00:09:30,661 What the bottom of the ocean really looked like. 180 00:09:30,803 --> 00:09:34,534 Heezen and Tharp Were masters of the echo sounder trace. 181 00:09:34,674 --> 00:09:36,232 Methodically piecing together the data 182 00:09:36,375 --> 00:09:40,277 from ships' tracks that criss-crossed the oceans. 183 00:09:40,413 --> 00:09:43,211 Forty years on Marie Tharp is retired, 184 00:09:43,349 --> 00:09:44,373 but still lives in the house 185 00:09:44,517 --> 00:09:47,543 Where she once Worked on the data. 186 00:09:47,687 --> 00:09:49,484 This exquisite hand-draWn map 187 00:09:49,622 --> 00:09:51,317 Was the result. 188 00:09:51,457 --> 00:09:54,017 Considering the scarity of the data in those days, 189 00:09:54,160 --> 00:09:57,095 the detail is astounding. 190 00:09:57,730 --> 00:09:58,754 Where We had a track 191 00:09:58,898 --> 00:10:01,890 We took it very seriously and exactly, 192 00:10:02,034 --> 00:10:03,899 but then it'd be so far to the next track 193 00:10:04,036 --> 00:10:07,028 that We had to do a bit of inspired guessing 194 00:10:07,173 --> 00:10:09,073 to fill in the space. 195 00:10:09,208 --> 00:10:10,607 That's Why the (NAME) quill pen 196 00:10:10,743 --> 00:10:14,076 and the sketching technique Was such a handy device 197 00:10:14,213 --> 00:10:16,545 'cos you could be very accurate Where you had data 198 00:10:16,682 --> 00:10:19,116 and you could make up and guess 199 00:10:19,251 --> 00:10:20,479 Where you didn't have data 200 00:10:20,620 --> 00:10:22,918 and still keep the same style. 201 00:10:23,055 --> 00:10:26,320 Actually in this area We didn't have any data at all, 202 00:10:26,459 --> 00:10:29,622 so that's Why We put the title in there. 203 00:10:31,397 --> 00:10:33,763 When they put the echo soundings together 204 00:10:33,899 --> 00:10:35,799 Bruce and Marie revealed the existence 205 00:10:35,935 --> 00:10:38,028 of a vast mountain chain, 206 00:10:38,170 --> 00:10:41,105 running doWn the centre of the North Atlantic. 207 00:10:43,109 --> 00:10:44,940 As more data became available 208 00:10:45,077 --> 00:10:47,773 they found that this range of submarine mountains 209 00:10:47,913 --> 00:10:50,575 snaked its Way around the entire globe 210 00:10:50,716 --> 00:10:54,152 for 60,000 kilometres. 211 00:10:55,821 --> 00:10:59,120 Bruce and Marie decided to publicise their discovery, 212 00:10:59,258 --> 00:11:02,352 but the reaction Wasn't quite What they'd hoped. 213 00:11:02,495 --> 00:11:04,224 Amazement at first, 214 00:11:04,363 --> 00:11:07,127 very shocking amazement 215 00:11:07,266 --> 00:11:12,465 and then doubt and then finally scorn. 216 00:11:12,605 --> 00:11:17,042 You knoW it Was a, a shocking thing to say. 217 00:11:17,176 --> 00:11:18,643 To make matters Worse, 218 00:11:18,778 --> 00:11:20,541 Marie told Bruce about something odd 219 00:11:20,680 --> 00:11:22,671 she'd found on the crest of the ridge, 220 00:11:22,815 --> 00:11:27,149 something Which supported Wegener's controversial idea. 221 00:11:27,286 --> 00:11:31,120 This is profiles across the Atlantic Ocean 222 00:11:31,257 --> 00:11:33,782 from our echo sounder. 223 00:11:33,926 --> 00:11:35,484 One thing Which Was unique 224 00:11:35,628 --> 00:11:37,823 to this preset of transatlantic profiles 225 00:11:37,963 --> 00:11:41,330 Was this valley at the crest of the mid-Atlantic Ridge. 226 00:11:41,467 --> 00:11:43,367 You see it, there is one mare 227 00:11:43,502 --> 00:11:47,871 and here's a cleft in the middle here 228 00:11:48,007 --> 00:11:50,771 l shoWed it to my boss, Bruze Heezen 229 00:11:50,910 --> 00:11:52,741 and l had plotted the position 230 00:11:52,878 --> 00:11:54,607 of this rift valley along the centre 231 00:11:54,747 --> 00:11:56,476 of the ocean Where it occurs 232 00:11:56,615 --> 00:11:58,344 and he just groaned and groaned 233 00:11:58,484 --> 00:11:59,951 and says ''this can't be, 234 00:12:00,086 --> 00:12:03,214 it looks just like Continental Drift'' 235 00:12:03,355 --> 00:12:06,552 because you could spot it Was a big cleft 236 00:12:06,692 --> 00:12:08,523 that's quite a large valley 237 00:12:08,661 --> 00:12:10,561 inside of a huge ridge. 238 00:12:10,696 --> 00:12:14,530 lt Was a big crack as if it could possibly mean 239 00:12:14,667 --> 00:12:18,034 that the continents Were pulling apart. 240 00:12:18,170 --> 00:12:19,398 Marie sketched the valley 241 00:12:19,538 --> 00:12:21,529 into the map of the North Atlantic, 242 00:12:21,674 --> 00:12:23,335 but it didn't end there. 243 00:12:23,476 --> 00:12:24,875 She and Bruce Went on to map 244 00:12:25,010 --> 00:12:26,500 all of the World's oceans, 245 00:12:26,645 --> 00:12:29,136 giving geologists their first vieW 246 00:12:29,281 --> 00:12:32,045 of the submarine World. 247 00:12:33,152 --> 00:12:34,551 Over the course of 20 years, 248 00:12:34,687 --> 00:12:37,383 since this initial map Was made by Bruce and Marie, 249 00:12:37,523 --> 00:12:40,515 they've dedicated their lives to looking at 250 00:12:40,659 --> 00:12:42,923 all of the echo sounding records 251 00:12:43,062 --> 00:12:45,622 that have been collected to produce a global map 252 00:12:45,765 --> 00:12:48,165 that shoWs us What the bottom of the ocean floor looks like. 253 00:12:48,300 --> 00:12:51,235 And this map is, 254 00:12:51,370 --> 00:12:53,133 really provides the geologist 255 00:12:53,272 --> 00:12:55,502 With a complete understanding 256 00:12:55,641 --> 00:12:57,973 of the hoW different the ocean floor 257 00:12:58,110 --> 00:13:00,101 is from the continents. 258 00:13:00,246 --> 00:13:01,178 The ridge system runs doWn 259 00:13:01,313 --> 00:13:02,803 the middle of the Atlantic Basin, 260 00:13:02,948 --> 00:13:05,644 betWeen Africa and Europe 261 00:13:05,785 --> 00:13:07,184 and North America 262 00:13:07,319 --> 00:13:08,479 and South America 263 00:13:08,621 --> 00:13:11,784 and it's this continuous line of rugged topography 264 00:13:11,924 --> 00:13:14,449 that goes all the Way doWn the ocean basins. 265 00:13:14,593 --> 00:13:16,151 Here into the lndian Ocean 266 00:13:16,295 --> 00:13:18,456 and out into the Pacific Ocean here, 267 00:13:18,597 --> 00:13:21,361 it is continuous throughout the globe. 268 00:13:21,500 --> 00:13:22,865 NoW you don't see that on the continents 269 00:13:23,002 --> 00:13:24,230 You can see mountain ranges 270 00:13:24,370 --> 00:13:25,769 and sometimes they're continuous, 271 00:13:25,905 --> 00:13:27,429 but never for 60,000 kilometres. 272 00:13:27,573 --> 00:13:30,701 You don't see that type of feature on the continent. 273 00:13:33,212 --> 00:13:35,305 Today at last satellite technology 274 00:13:35,447 --> 00:13:39,144 can reveal directly the shape of the ocean floor. 275 00:13:40,452 --> 00:13:42,215 Remove the skin of Water 276 00:13:42,354 --> 00:13:43,719 and the backbone of the World 277 00:13:43,856 --> 00:13:46,916 can be seen from space. 278 00:14:05,611 --> 00:14:08,341 The discovery of this vast mid-ocean ridge system 279 00:14:08,480 --> 00:14:10,038 Was a revelation 280 00:14:10,182 --> 00:14:13,117 but nobody kneW hoW it had got there. 281 00:14:13,252 --> 00:14:15,482 Then, as people began to look more closely 282 00:14:15,621 --> 00:14:16,610 at the sea floor, 283 00:14:16,755 --> 00:14:18,780 more striking differences betWeen the oceans 284 00:14:18,924 --> 00:14:22,223 and the continents began to emerge. 285 00:14:24,496 --> 00:14:25,622 At the end of the Second World War, 286 00:14:25,764 --> 00:14:28,289 there Was a neW breed of marine scientist, 287 00:14:28,434 --> 00:14:32,200 and they set out to study the ocean floor 288 00:14:32,338 --> 00:14:35,273 by dropping explosives over the side of the ship - 289 00:14:35,407 --> 00:14:36,806 and they had plenty of those - 290 00:14:36,942 --> 00:14:38,637 and listening to them With hydrophones 291 00:14:38,777 --> 00:14:41,405 that had been used for submarine detection. 292 00:14:44,183 --> 00:14:47,846 The technique Was called seismic profiling. 293 00:14:47,987 --> 00:14:50,785 ln the early days it Was a fairly hazardous enterprise. 294 00:14:50,923 --> 00:14:55,053 Explosives Were simply hurled overboard and detonated. 295 00:14:57,129 --> 00:14:58,221 The shock Waves penetrated 296 00:14:58,364 --> 00:15:01,663 deep into the rock beneath the ocean. 297 00:15:02,668 --> 00:15:03,896 By studying the Way the sound 298 00:15:04,036 --> 00:15:05,469 Was reflected back, 299 00:15:05,604 --> 00:15:06,832 the ocean-going geologists 300 00:15:06,972 --> 00:15:10,772 measured the thickness of the ocean crust. 301 00:15:10,910 --> 00:15:12,036 When they did this, 302 00:15:12,177 --> 00:15:15,237 they discovered tWo very important things. 303 00:15:15,381 --> 00:15:17,042 One Was, that the ocean crust 304 00:15:17,182 --> 00:15:18,911 Was much thinner than the continental crust, 305 00:15:19,051 --> 00:15:21,349 six kilometres instead of 30 kilometres 306 00:15:21,487 --> 00:15:23,648 and the other is, that the ocean crust 307 00:15:23,789 --> 00:15:25,984 has the same thickness and the same structure 308 00:15:26,125 --> 00:15:28,855 all the Way round the World 309 00:15:30,462 --> 00:15:33,192 Which indicated it formed by the same process 310 00:15:33,332 --> 00:15:35,630 all the Way round the World. 311 00:15:37,069 --> 00:15:40,129 That Was a truly fundamental discovery. 312 00:15:40,272 --> 00:15:42,331 The seismic research helped scientists 313 00:15:42,474 --> 00:15:45,705 come to realise a crucial fact 314 00:15:47,446 --> 00:15:50,609 the ocean floor and the continents looke dso different 315 00:15:50,749 --> 00:15:52,239 they had to have been created 316 00:15:52,384 --> 00:15:55,080 in entirely different Ways. 317 00:15:56,288 --> 00:15:59,018 But the process that created the ocean basins 318 00:15:59,158 --> 00:16:01,752 remained a mystery until another technique 319 00:16:01,894 --> 00:16:05,330 began picking up important clues. 320 00:16:07,499 --> 00:16:08,796 lt's midnight. 321 00:16:08,934 --> 00:16:10,959 The research vessel Atlantis is approaching 322 00:16:11,103 --> 00:16:13,298 the centre of the mid-Atlantic ridge 323 00:16:13,439 --> 00:16:18,103 and Joe Cann is supervising the launch of a dredge bucket. 324 00:16:18,711 --> 00:16:19,837 Over the next couple 325 00:16:19,979 --> 00:16:21,947 of hours the dredge Will be loWered thousands of metres 326 00:16:22,081 --> 00:16:23,571 until it touches bottom, 327 00:16:23,716 --> 00:16:27,447 then dragged along as the ship creeps forward. 328 00:16:28,921 --> 00:16:30,980 ln the process, the bucket should scoop up 329 00:16:31,123 --> 00:16:34,320 some of the rocks that litter the sea floor. 330 00:16:35,861 --> 00:16:40,161 Bridge, We're going to put another 30 metres of Wire out. 331 00:16:40,299 --> 00:16:41,561 Right, 15. 332 00:16:41,700 --> 00:16:44,897 10 maybe. OK. 333 00:16:47,639 --> 00:16:48,731 The problems are that 334 00:16:48,874 --> 00:16:53,106 We've got, We're in 2,500 metres of Water - 335 00:16:53,245 --> 00:16:54,837 and We've got a dredge being pulled 336 00:16:54,980 --> 00:16:57,847 over a rocky bottom With unknoWn rocks, 337 00:16:57,983 --> 00:17:00,076 some of Which are pretty tough rocks. 338 00:17:00,219 --> 00:17:01,117 The ship is going along 339 00:17:01,253 --> 00:17:04,279 at half a knot inexorably. 340 00:17:04,423 --> 00:17:05,617 What We must avoid is, 341 00:17:05,758 --> 00:17:07,658 is being snagged up on a rock doWn there. 342 00:17:07,793 --> 00:17:10,091 lf We get snagged up and don't notice it, 343 00:17:10,229 --> 00:17:11,321 the tension Will build up in the Wire. 344 00:17:11,463 --> 00:17:14,830 The Wire parts. lt parts on deck. 345 00:17:14,967 --> 00:17:16,559 Loose end Whips around, 346 00:17:16,702 --> 00:17:19,296 cause a lot of damage, kills people. 347 00:17:22,174 --> 00:17:23,505 ln the old days We didn't knoW Whether 348 00:17:23,642 --> 00:17:25,610 the ship Was moving over the bottom at all. 349 00:17:25,744 --> 00:17:26,642 We could put Wire out - 350 00:17:26,779 --> 00:17:28,246 We didn't knoW Whether the dredge Was on the bottom. 351 00:17:28,380 --> 00:17:32,646 We didn't knoW Where the bottom Was properly 352 00:17:32,785 --> 00:17:33,979 and We had to resort 353 00:17:34,119 --> 00:17:36,644 to very crude techniques such as - 354 00:17:36,789 --> 00:17:37,448 When the dredge Was out- 355 00:17:37,589 --> 00:17:39,921 We Would sit on the main Warp 356 00:17:40,059 --> 00:17:42,391 on the after deck feeling the nubbles 357 00:17:42,528 --> 00:17:43,927 coming up from the deep ocean floor. 358 00:17:44,063 --> 00:17:47,965 lt's very evocative - it's very, very... 359 00:17:49,468 --> 00:17:52,266 Uncomfortable, l Would have thought 360 00:17:52,404 --> 00:17:54,269 lt Was very uncomfortable, very dangerous 361 00:17:54,406 --> 00:17:56,533 but you felt in touch With the ocean floor 362 00:17:56,675 --> 00:17:57,869 like you don't at the present day. 363 00:17:58,010 --> 00:17:59,272 You felt deeply in touch With it, 364 00:17:59,411 --> 00:18:01,276 through your bottom. 365 00:18:01,413 --> 00:18:04,280 l have a dredge in sight, dredge in sight. 366 00:18:04,416 --> 00:18:06,441 Dredger in sight 367 00:18:06,585 --> 00:18:08,485 Up easy. 368 00:18:09,388 --> 00:18:11,288 There are certainly rocks in there. l mean, 369 00:18:11,423 --> 00:18:13,823 you can see the bottom of the bag bulging. 370 00:18:13,959 --> 00:18:15,187 First one for the neW ship. 371 00:18:15,327 --> 00:18:17,295 That's impressive. 372 00:18:18,997 --> 00:18:20,862 Oh yes, oh yes. 373 00:18:20,999 --> 00:18:22,796 When scientists began recovering rocks 374 00:18:22,935 --> 00:18:24,698 from around the mid ocean ridge, 375 00:18:24,837 --> 00:18:27,829 they found they Were mainly volcanic. 376 00:18:27,973 --> 00:18:31,238 These aren't the kind of things that you see 377 00:18:31,376 --> 00:18:33,776 in your back garden at home. 378 00:18:33,912 --> 00:18:35,971 They're basalts. They're also submarine basalts. 379 00:18:36,115 --> 00:18:38,709 You can tell 'cos they chill to this bright, 380 00:18:38,851 --> 00:18:40,614 glassy margin chilled against the Water 381 00:18:40,752 --> 00:18:42,515 When they erupted. 382 00:18:42,654 --> 00:18:43,450 And they're very sharp. 383 00:18:43,589 --> 00:18:45,750 The glass is very young and very sharp - 384 00:18:45,891 --> 00:18:50,260 as you can see, l've cut my finger on the fragment. 385 00:18:51,196 --> 00:18:53,357 These rocks are young. 386 00:18:53,499 --> 00:18:56,297 SomeWhere, 2000 metres beloW, 387 00:18:56,435 --> 00:19:00,166 submarine volcanoes have recently been erupting. 388 00:19:00,305 --> 00:19:01,670 We knoW they're young, 389 00:19:01,807 --> 00:19:03,434 because of the fresh glass 390 00:19:03,575 --> 00:19:04,940 and they're also highly magnetic. 391 00:19:05,077 --> 00:19:06,908 lf l take my compass out, 392 00:19:07,045 --> 00:19:09,104 it's just an ordinary compass 393 00:19:09,248 --> 00:19:10,715 that you use any day, 394 00:19:10,849 --> 00:19:14,046 l take one of these rocks and bring it up to it, 395 00:19:14,186 --> 00:19:15,483 you see, if you look carefully 396 00:19:15,621 --> 00:19:18,715 that the needle deflects a bit. 397 00:19:18,857 --> 00:19:21,621 Not much, about 10 degrees. 398 00:19:22,327 --> 00:19:23,851 But it deflects enough to shoW 399 00:19:23,996 --> 00:19:28,626 that the rock must be very magnetic indeed. 400 00:19:30,969 --> 00:19:32,459 Here We go. 401 00:19:33,539 --> 00:19:35,234 Scientists Were still perplexed about 402 00:19:35,374 --> 00:19:37,137 What Was going on doWn there. 403 00:19:37,276 --> 00:19:40,006 But once they realised ocean rocks could be magnetic, 404 00:19:40,145 --> 00:19:43,512 it opened up a neW avenue of investigation. 405 00:19:49,054 --> 00:19:51,215 OK lt's in the Water noW. 406 00:19:52,858 --> 00:19:54,325 That's a magnetometer 407 00:19:54,459 --> 00:19:55,756 and it is toWed behind the ship. 408 00:19:55,894 --> 00:19:56,883 lt's an instrument that gives us 409 00:19:57,029 --> 00:19:59,964 a very detailed reading 410 00:20:00,098 --> 00:20:01,759 of the earth's magnetic field, 411 00:20:01,900 --> 00:20:03,800 so it's very, very sensitive. 412 00:20:03,936 --> 00:20:06,530 Basically, it can pick up the small variations 413 00:20:06,672 --> 00:20:08,230 in the earth's magnetic field 414 00:20:08,373 --> 00:20:09,931 that are caused by the rocks 415 00:20:10,075 --> 00:20:12,942 in the various layers in the ocean crust. 416 00:20:14,646 --> 00:20:18,241 Magnetometer surveys started in earnest in the 1950s, 417 00:20:18,383 --> 00:20:21,375 often in extraordinary detail. 418 00:20:21,520 --> 00:20:22,987 Certain areas Were sailed over 419 00:20:23,121 --> 00:20:25,783 in a series of tightly-packed parallel lines 420 00:20:25,924 --> 00:20:28,654 to ensure that nothing Was missed out. 421 00:20:28,794 --> 00:20:29,988 Where the ships Went, 422 00:20:30,128 --> 00:20:32,722 magnetometers folloWed behind. 423 00:20:36,435 --> 00:20:40,235 Magnetic rocks distort the earth's magnetic field, 424 00:20:40,372 --> 00:20:44,331 sometimes making it stronger than expected, sometimes Weaker. 425 00:20:44,476 --> 00:20:48,970 These differences are called positive and negative anomalies. 426 00:20:49,114 --> 00:20:51,105 When the data from the first detailed survey 427 00:20:51,250 --> 00:20:52,274 Were put together, 428 00:20:52,417 --> 00:20:56,012 the scientists Were dumbfounded by the result. 429 00:20:56,154 --> 00:20:58,987 Stripes of magnetic anomalies. 430 00:20:59,124 --> 00:21:01,854 NoW this Was back in 1961 431 00:21:01,994 --> 00:21:03,655 the most amazing thing. 432 00:21:03,795 --> 00:21:05,660 Here's the coast of the United States. 433 00:21:05,797 --> 00:21:06,923 Here's Canada, 434 00:21:07,065 --> 00:21:09,465 and here is the magnetic anomaly map offshore. 435 00:21:09,601 --> 00:21:11,000 Black is positive anomalies, 436 00:21:11,136 --> 00:21:12,569 White is negative anomalies 437 00:21:12,704 --> 00:21:16,140 and see hoW they're all form these astonishing stripes. 438 00:21:16,275 --> 00:21:19,767 Nothing like this has ever been seen on the continents. 439 00:21:19,911 --> 00:21:22,471 And yet the ocean floor appeared to be made 440 00:21:22,614 --> 00:21:25,947 of these parallel stripes of positive 441 00:21:26,084 --> 00:21:28,450 and negative anomalies. 442 00:21:30,122 --> 00:21:31,248 By the early '60s 443 00:21:31,390 --> 00:21:34,052 scientists kneW a good deal about the ocean floor, 444 00:21:34,192 --> 00:21:36,717 but none of it made much sense. 445 00:21:36,862 --> 00:21:39,626 ln some Ways it Was a very uniform picture. 446 00:21:39,765 --> 00:21:42,256 The crust Was all the same thickness, 447 00:21:42,401 --> 00:21:44,733 it Was all much younger than the continents 448 00:21:44,870 --> 00:21:48,033 and it Was nearly all made of volcanic rock. 449 00:21:48,173 --> 00:21:50,573 Also, running doWn the centre of the basins, 450 00:21:50,709 --> 00:21:52,734 Was a continuous mountain range 451 00:21:52,878 --> 00:21:56,939 and along the crest Was a continuous rift valley. 452 00:21:57,082 --> 00:21:59,073 This pattern Was so radically different 453 00:21:59,217 --> 00:22:01,014 from anything on the continents 454 00:22:01,153 --> 00:22:03,986 that it demanded an explanation. 455 00:22:10,295 --> 00:22:13,594 The turning point finally came in 1962, 456 00:22:13,732 --> 00:22:15,427 at a lecture given here in Cambridge 457 00:22:15,567 --> 00:22:17,091 Which revived Wegener's idea 458 00:22:17,235 --> 00:22:19,533 of continental drift. 459 00:22:19,671 --> 00:22:22,139 Attending the lecture Was Fred Vine, 460 00:22:22,274 --> 00:22:24,902 Who Was just a geology student at the time, 461 00:22:25,043 --> 00:22:28,945 but his interest in the subject had been triggered long before. 462 00:22:29,781 --> 00:22:31,043 l first encountered the concept 463 00:22:31,183 --> 00:22:32,980 of continental drift in a school text book 464 00:22:33,118 --> 00:22:35,177 When l Was about 14. And l opened the text book, 465 00:22:35,320 --> 00:22:37,515 and l think it Was right at the very beginning, 466 00:22:37,656 --> 00:22:39,180 the first page of the first chapter pretty Well, 467 00:22:39,324 --> 00:22:42,088 Where it shoWed a fit of South America and Africa, 468 00:22:42,227 --> 00:22:43,854 the classic sort of fit of the continents, 469 00:22:43,995 --> 00:22:45,587 and it said that it Was - 470 00:22:45,731 --> 00:22:48,097 some people thought that these continents 471 00:22:48,233 --> 00:22:50,724 may once have been juxtaposed in this Way 472 00:22:50,869 --> 00:22:52,860 and have drifted apart. 473 00:22:53,004 --> 00:22:54,699 But no-one really kneW. 474 00:22:54,840 --> 00:22:57,968 And it has never been proved or disproved. 475 00:22:58,110 --> 00:22:59,941 And l thought that this Was just incredible. 476 00:23:00,078 --> 00:23:01,238 l mean incredible to think that 477 00:23:01,380 --> 00:23:02,779 this may of once been the case 478 00:23:02,914 --> 00:23:03,778 and it may have happened, 479 00:23:03,915 --> 00:23:05,746 so that the Whole scale of it you knoW, 480 00:23:05,884 --> 00:23:08,045 the mechanism of it Was mind boggling. 481 00:23:08,186 --> 00:23:10,279 The other thing tha l just couldn't really cope 482 00:23:10,422 --> 00:23:12,652 With Was that nobody kneW one Way or the other, 483 00:23:12,791 --> 00:23:15,021 and l felt it Was just time that We found out. 484 00:23:15,160 --> 00:23:17,094 l mean there must be some Way of finding out 485 00:23:17,229 --> 00:23:19,754 such a fundamental fact about the earth. 486 00:23:19,898 --> 00:23:24,528 The birth of the oceans is still a matter of some conjecture. 487 00:23:24,669 --> 00:23:26,864 At that lecture in 1962 488 00:23:27,005 --> 00:23:31,374 Fred Vine listened to an American geologist Harry Hess. 489 00:23:31,510 --> 00:23:35,310 Hess explained his ideas of hoW the ocean basins had formed. 490 00:23:35,447 --> 00:23:38,814 lt's a lecture Vine remembers vividly today. 491 00:23:39,651 --> 00:23:41,551 Hess l guess Was the first person 492 00:23:41,686 --> 00:23:46,055 to try to synthesise all the neW data. 493 00:23:46,191 --> 00:23:48,455 lt Was a pretty daring synthesis anyway 494 00:23:48,593 --> 00:23:52,051 and it Was regarded as being very speculative at the time. 495 00:23:52,197 --> 00:23:52,993 l thought it Was very exciting 496 00:23:53,131 --> 00:23:56,328 because it fitted in With continental drift. 497 00:23:57,068 --> 00:23:58,763 Hess believed the mid ocean ridge 498 00:23:58,904 --> 00:24:00,428 Was a vast crack 499 00:24:00,572 --> 00:24:03,564 Where the Earth Was splitting apart. 500 00:24:04,109 --> 00:24:05,337 He suggested molten rock 501 00:24:05,477 --> 00:24:07,809 Was constantly erupting in the crack, 502 00:24:07,946 --> 00:24:10,915 continuously forming neW ocean floor. 503 00:24:11,516 --> 00:24:14,781 Hess Was basically describing an enormous conveyor belt 504 00:24:14,920 --> 00:24:17,718 With neW ocean crust forming at the mid ocean ridge 505 00:24:17,856 --> 00:24:19,915 and then moving aWay. 506 00:24:20,492 --> 00:24:22,756 lt explained almost all the observations; 507 00:24:22,894 --> 00:24:24,384 the ridge and its valley, 508 00:24:24,529 --> 00:24:27,020 the consistent layer of young volcanic rock. 509 00:24:27,165 --> 00:24:29,963 And it also explained continental drift. 510 00:24:30,101 --> 00:24:33,093 The continents didn't sail through the oceanic rock, 511 00:24:33,238 --> 00:24:35,468 they just moved With it. 512 00:24:35,607 --> 00:24:38,201 lt Was an extraordinary idea. 513 00:24:38,343 --> 00:24:41,938 Hess himself called it geo-poetry. 514 00:24:42,080 --> 00:24:43,570 lronically the one line of evidence 515 00:24:43,715 --> 00:24:45,114 that could make it stand up 516 00:24:45,250 --> 00:24:47,480 Was the very element Hess left out; 517 00:24:47,619 --> 00:24:49,678 magnetism. 518 00:24:50,355 --> 00:24:53,950 And it just so happened that magnetism of ocean rocks 519 00:24:54,092 --> 00:24:57,653 Was the subject of Fred Vine's PhD. 520 00:25:00,432 --> 00:25:02,059 Well, this is the very room 521 00:25:02,200 --> 00:25:04,259 in Which l Worked as a graduate student 522 00:25:04,402 --> 00:25:06,427 and it's the first time l've been back in 35 years, 523 00:25:06,571 --> 00:25:07,697 so it's rather fun. 524 00:25:07,839 --> 00:25:09,397 lt's exactly the same essentially. 525 00:25:09,541 --> 00:25:12,339 l came here in October 1962 526 00:25:12,477 --> 00:25:15,173 to Work With Drummond MattheWs, 527 00:25:15,313 --> 00:25:17,474 Who Was a geologist. 528 00:25:17,616 --> 00:25:19,083 Drummond at the time Was actually 529 00:25:19,217 --> 00:25:21,310 at sea making a detailed survey 530 00:25:21,453 --> 00:25:23,387 of the north-West lndian Ocean 531 00:25:23,522 --> 00:25:25,820 and this involved measuring the shape 532 00:25:25,957 --> 00:25:27,618 of the ocean floor, 533 00:25:27,759 --> 00:25:29,090 the gravity field over it 534 00:25:29,227 --> 00:25:31,161 and the magnetic field over it 535 00:25:31,296 --> 00:25:32,490 and l Was specifically 536 00:25:32,631 --> 00:25:35,156 as his first graduate student actually, 537 00:25:35,300 --> 00:25:38,497 to Work on the magnetic data. 538 00:25:38,637 --> 00:25:40,730 l decided that the Way to go about this problem 539 00:25:40,872 --> 00:25:42,840 Was to use a digital computer - 540 00:25:42,974 --> 00:25:44,407 this is Edzac 2 541 00:25:44,543 --> 00:25:47,535 one of the very feW in the World at that time. 542 00:25:47,679 --> 00:25:48,976 l don't think l'm actually in this queue 543 00:25:49,114 --> 00:25:50,342 but l could be 544 00:25:50,482 --> 00:25:52,279 because l think it Was every hour 545 00:25:52,417 --> 00:25:53,247 for about 5 minutes 546 00:25:53,385 --> 00:25:55,979 We Were alloWed to test our programmes on, 547 00:25:56,121 --> 00:25:58,248 on the computer. 548 00:25:58,390 --> 00:25:59,448 Vine had a programme 549 00:25:59,591 --> 00:26:02,458 that analysed the magnetic anomalies. 550 00:26:02,594 --> 00:26:06,223 He entered magnetic data from the survey into the computer. 551 00:26:06,364 --> 00:26:09,026 lt then calculated What sort of magnetic field 552 00:26:09,167 --> 00:26:12,102 could cause the anomalies that had been measured. 553 00:26:12,237 --> 00:26:13,932 What the computer told Vine 554 00:26:14,072 --> 00:26:16,097 Was quite astonishing 555 00:26:16,241 --> 00:26:18,607 The all important result that it came up With - 556 00:26:18,743 --> 00:26:20,438 and it Was a rather surprising result in many Ways - 557 00:26:20,579 --> 00:26:22,911 Was that large areas of the survey, 558 00:26:23,048 --> 00:26:26,347 large areas of the ocean floor in that survey area 559 00:26:26,484 --> 00:26:28,281 Were reversely magnetised. 560 00:26:28,420 --> 00:26:29,910 That is that it's as though the rocks 561 00:26:30,055 --> 00:26:32,080 had been magnetised at a time 562 00:26:32,223 --> 00:26:33,986 When the earth's magnetic field Was the reverse 563 00:26:34,125 --> 00:26:35,990 of its present direction, that, 564 00:26:36,127 --> 00:26:39,494 that a compass at that time Would have poined to the south 565 00:26:39,631 --> 00:26:42,657 rather than to north, geographic pole. 566 00:26:43,602 --> 00:26:45,399 The theory that the Earth's magnetic field 567 00:26:45,537 --> 00:26:47,971 has repeatedly flipped to and fro 568 00:26:48,106 --> 00:26:50,939 had been hotly debated for years. 569 00:26:51,076 --> 00:26:53,067 No consensus had been reached, 570 00:26:53,211 --> 00:26:56,203 but if magnetic reversals had really happened 571 00:26:56,348 --> 00:26:58,839 they Would have left their mark. 572 00:26:59,818 --> 00:27:02,844 As volcanic rock erupts and then cools 573 00:27:02,988 --> 00:27:04,216 it records the direction 574 00:27:04,356 --> 00:27:05,653 of the Earth's magnetic field 575 00:27:05,790 --> 00:27:08,258 at the time of the eruption. 576 00:27:08,393 --> 00:27:10,361 lf the magnetic field flipped 577 00:27:10,495 --> 00:27:14,727 such reversals Would remain captured in the rocks. 578 00:27:16,201 --> 00:27:17,759 lt Was really simply a matter of combining 579 00:27:17,902 --> 00:27:19,631 that With Harry hess's idea 580 00:27:19,771 --> 00:27:21,238 of sea-floor spreading. 581 00:27:21,373 --> 00:27:23,102 l mean Harry painted this picture 582 00:27:23,241 --> 00:27:24,173 of conveyor belt, 583 00:27:24,309 --> 00:27:25,901 this running out symmetrically 584 00:27:26,044 --> 00:27:28,308 on either side of the mid-ocean ridge 585 00:27:28,446 --> 00:27:29,970 What in effect Was to convert 586 00:27:30,115 --> 00:27:31,514 the conveyor belt into a tape-recorder, 587 00:27:31,650 --> 00:27:33,277 a sort of tWin-headed tape-recorder 588 00:27:33,418 --> 00:27:35,716 running out symmetrically. 589 00:27:35,854 --> 00:27:38,152 Vine's idea Was that if the Earth's field 590 00:27:38,289 --> 00:27:40,189 Would make compasses point north, 591 00:27:40,325 --> 00:27:43,294 then any molten rock erupting at the ridge at that time 592 00:27:43,428 --> 00:27:46,397 Would be magnetised in that direction. 593 00:27:46,531 --> 00:27:48,556 lf the Earth's field then flipped, 594 00:27:48,700 --> 00:27:50,759 any more neW rock formed at the ridge 595 00:27:50,902 --> 00:27:54,065 Would be magnetised in the neW direction. 596 00:27:55,273 --> 00:27:57,264 Each time the magnetic field flipped, 597 00:27:57,409 --> 00:28:01,470 so Would the magnetisation of the neWly-forming crust. 598 00:28:03,314 --> 00:28:05,339 But since nobody had irrefutable evidence 599 00:28:05,483 --> 00:28:07,041 of magnetic reversals, 600 00:28:07,185 --> 00:28:10,279 the idea Went doWn like a lead balloon. 601 00:28:10,422 --> 00:28:12,652 lt Was not generally accepted particularly 602 00:28:12,791 --> 00:28:16,158 by people Who Were closest to, to the field actually. 603 00:28:16,294 --> 00:28:17,454 l suppose an element, you knoW it Was, 604 00:28:17,595 --> 00:28:19,825 it Was a Wild idea or seemed, thought to be a Wild idea 605 00:28:19,964 --> 00:28:22,262 and it Wasn't their idea so Why believe it, 606 00:28:22,400 --> 00:28:24,129 but one can find quite a lot of references 607 00:28:24,269 --> 00:28:26,499 in the literature in 64/65 608 00:28:26,638 --> 00:28:29,539 Where people Were really quite rude about it actually. 609 00:28:29,674 --> 00:28:32,472 lt didn't bother me particularly but... 610 00:28:34,179 --> 00:28:38,138 Fortunately, the hypothesis also made a prediction. 611 00:28:38,283 --> 00:28:40,615 lt predicted that the pattern of magnetic stripes 612 00:28:40,752 --> 00:28:42,481 on either side of the mid ocean ridge 613 00:28:42,620 --> 00:28:44,986 Would be symmetrical. 614 00:28:45,123 --> 00:28:46,351 So Vine looked carefully 615 00:28:46,491 --> 00:28:47,788 at the map of magnetic stripes 616 00:28:47,926 --> 00:28:49,917 from the Pacific Ocean. 617 00:28:50,061 --> 00:28:51,688 Once he kneW What he Was looking for, 618 00:28:51,830 --> 00:28:55,425 he found the symmetry staring him in the face. 619 00:28:55,934 --> 00:28:58,459 This stripe of positively magnetised rock 620 00:28:58,603 --> 00:29:01,401 actually marks a section of the ridge. 621 00:29:01,539 --> 00:29:02,938 On either side the pattern of 622 00:29:03,074 --> 00:29:05,770 White and black stripes stretches out 623 00:29:05,910 --> 00:29:08,208 in a mirror image. 624 00:29:08,346 --> 00:29:10,405 lncredibly the symmetry in this diagram 625 00:29:10,548 --> 00:29:13,574 Was not realised until 1965, 626 00:29:13,718 --> 00:29:16,949 that the survey had been extance at 1961 627 00:29:17,088 --> 00:29:18,783 and no-one had noticed the symmetry 628 00:29:18,923 --> 00:29:22,359 about What We noW call the (NAME) ridge. 629 00:29:22,927 --> 00:29:25,418 NoW people began to believe Vine 630 00:29:25,563 --> 00:29:27,588 and they started to find symmetrical patterns 631 00:29:27,732 --> 00:29:29,632 in other data. 632 00:29:32,771 --> 00:29:34,295 The theory of sea floor spreading 633 00:29:34,439 --> 00:29:37,203 had been tested and proved. 634 00:29:37,342 --> 00:29:39,936 With it, Alfred Wegener's idea of continental drift 635 00:29:40,078 --> 00:29:42,012 took on a neW lease of life. 636 00:29:42,147 --> 00:29:44,707 At last it Was possible to understand 637 00:29:44,849 --> 00:29:48,410 hoW continents could drift sloWly but inexorably 638 00:29:48,553 --> 00:29:51,386 across the face of the planet. 639 00:29:57,328 --> 00:29:58,659 But at the heart of the theory 640 00:29:58,797 --> 00:30:01,664 lay a feature that no-one had ever set eyes on 641 00:30:01,800 --> 00:30:03,893 the remarkable volcanic mountain chain 642 00:30:04,035 --> 00:30:06,595 Where oceanic crust is generated, 643 00:30:06,738 --> 00:30:08,899 the mid Atlantic Ridge. 644 00:30:09,040 --> 00:30:10,667 Geologists Would never be satisfied 645 00:30:10,809 --> 00:30:14,301 until they had seen it for themselves. 646 00:30:18,116 --> 00:30:20,846 After 6 days straight sail from Bermuda, 647 00:30:20,985 --> 00:30:22,577 the Atlantis is sitting directly 648 00:30:22,720 --> 00:30:24,688 on top of the ridge. 649 00:30:24,823 --> 00:30:26,051 But a different vessel is needed 650 00:30:26,191 --> 00:30:28,159 to make the final leg of the journey; 651 00:30:28,293 --> 00:30:30,420 to the ocean floor. 652 00:31:08,766 --> 00:31:10,256 This is a submersible ''Alvin'' 653 00:31:10,401 --> 00:31:12,369 capable of diving to forty-five hundred metres, 654 00:31:12,503 --> 00:31:14,528 Which is roughly three miles deep 655 00:31:14,672 --> 00:31:15,934 under the ocean. 656 00:31:16,074 --> 00:31:18,599 lt Withstands pressures of up to sixty-six hundred PSl, 657 00:31:18,743 --> 00:31:22,907 Which is about tWo good sized elephants sitting on your lap. 658 00:31:24,349 --> 00:31:27,079 The titanium sphere is about tWo inches thick 659 00:31:27,218 --> 00:31:30,085 and inside it sit three people, the pilot and tWo observers. 660 00:31:30,221 --> 00:31:32,689 lt gets a little thicker up by the vieW ports, 661 00:31:32,824 --> 00:31:34,189 it's about three and half inches thick. 662 00:31:34,325 --> 00:31:35,622 The vieW ports are made of plastic 663 00:31:35,760 --> 00:31:38,786 so that they're tough and not brittle like glass Would be. 664 00:31:38,930 --> 00:31:41,398 Alvin dives by being loaded With Weights. 665 00:31:41,532 --> 00:31:42,658 When it's ready to surface 666 00:31:42,800 --> 00:31:44,392 the Weights are dumped 667 00:31:44,535 --> 00:31:47,299 and the sub becomes light enough to float up. 668 00:31:47,438 --> 00:31:48,700 lf the submarine Was to be stuck 669 00:31:48,840 --> 00:31:52,207 on the bottom for some reason, snagged on a, 670 00:31:52,343 --> 00:31:54,777 anything, the releasing of Weights 671 00:31:54,913 --> 00:31:56,210 might not be enough. 672 00:31:56,347 --> 00:31:57,974 So the submarine can try to drive up 673 00:31:58,116 --> 00:31:59,913 With its thrusters and if that's not enough, 674 00:32:00,051 --> 00:32:01,780 We could drop various pieces of gear, 675 00:32:01,920 --> 00:32:03,353 We can release the science basket - 676 00:32:03,488 --> 00:32:04,750 get rid of the science gear. 677 00:32:04,889 --> 00:32:06,686 We can release the manipulators. 678 00:32:06,824 --> 00:32:09,452 We can even try jettisoning our batteries, 679 00:32:09,594 --> 00:32:11,323 Which Would then leave us Without poWer. 680 00:32:11,462 --> 00:32:12,759 lf all that's not enough, 681 00:32:12,897 --> 00:32:15,331 We can last on the bottom for three days and, 682 00:32:15,466 --> 00:32:17,024 if there's no prospect of rescue, 683 00:32:17,168 --> 00:32:18,601 We can actually release the sphere 684 00:32:18,736 --> 00:32:19,964 from the rest of the submarine 685 00:32:20,104 --> 00:32:21,833 and it Will float up on its oWn. 686 00:32:21,973 --> 00:32:24,032 Unfortunately, it Won't float up right side up. 687 00:32:24,175 --> 00:32:25,665 We don't really knoW exactly hoW fast 688 00:32:25,810 --> 00:32:26,799 or in What attitude. 689 00:32:26,945 --> 00:32:28,913 lt'll probably spin like a ball and it - 690 00:32:29,047 --> 00:32:31,447 might be quite a Wild ride. 691 00:32:36,421 --> 00:32:37,649 Matt, l Wanted to talk to you a little bit 692 00:32:37,789 --> 00:32:39,780 about Where We are planning on diving tomorroW. 693 00:32:39,924 --> 00:32:42,722 So if you turn on that light for a second, thanks. 694 00:32:42,860 --> 00:32:44,020 So We've got this big sea mound 695 00:32:44,162 --> 00:32:45,254 in the middle of the Rift Valley, 696 00:32:45,396 --> 00:32:46,260 the place Where We are going to dive 697 00:32:46,397 --> 00:32:47,694 is right here on the summit. 698 00:32:47,832 --> 00:32:48,594 lt's an area Where... 699 00:32:48,733 --> 00:32:50,064 The evening before the dive, 700 00:32:50,201 --> 00:32:52,692 project leader Dan Fornari finalises details 701 00:32:52,837 --> 00:32:54,304 With Susan Humphris, 702 00:32:54,439 --> 00:32:57,340 the scientist Who Will be on board the sub. 703 00:32:57,475 --> 00:33:00,035 Matt Heintz has been chosen as pilot. 704 00:33:00,645 --> 00:33:02,806 So you're not talking more than a kilometre 705 00:33:02,947 --> 00:33:04,539 in any direction that you'll have to travel. 706 00:33:04,682 --> 00:33:06,274 Right sloW Yes, so l think the thing do 707 00:33:06,417 --> 00:33:08,715 maybe is to start in here and then Work our Way 708 00:33:08,853 --> 00:33:10,286 up the slope Where the dredge Went. 709 00:33:10,421 --> 00:33:13,254 lt looks like there might some sort of fairly steep cliff 710 00:33:13,391 --> 00:33:16,189 or scarp here that We'll have to go up, 711 00:33:16,327 --> 00:33:19,728 you knoW, it looks like it might be about 100 metres high. 712 00:33:19,864 --> 00:33:22,628 Got propulsion.. Hydraulics on. 713 00:33:24,202 --> 00:33:25,931 Good, good. 714 00:33:26,070 --> 00:33:28,061 Good luck. Thanks. 715 00:33:30,208 --> 00:33:32,142 At first, When you get in the sub, 716 00:33:32,276 --> 00:33:33,641 because it's been sitting out on deck, 717 00:33:33,778 --> 00:33:36,406 it's usually very, very hot and stuffy. 718 00:33:36,547 --> 00:33:38,071 And the first impression 719 00:33:38,216 --> 00:33:42,118 is one of being incredibly cramped. 720 00:33:43,554 --> 00:33:45,021 We standing by on the fan tail, 721 00:33:45,156 --> 00:33:46,748 ready to launch. 722 00:33:46,891 --> 00:33:49,883 Roger that. Go ahead and commence launch 723 00:33:58,936 --> 00:34:02,963 l alWays get the feeling of sort of pent up excitement, 724 00:34:03,107 --> 00:34:05,541 but some nervousness - 725 00:34:07,845 --> 00:34:10,973 sWinging out over the stern of the ship 726 00:34:11,115 --> 00:34:12,412 looking out over the Waves 727 00:34:12,550 --> 00:34:13,949 and realising that all of a minute 728 00:34:14,085 --> 00:34:15,882 you're going to splosh doWn in there 729 00:34:16,020 --> 00:34:17,282 and the porthole 730 00:34:17,422 --> 00:34:21,256 is going to look like the inside of a Washing machine. 731 00:34:55,726 --> 00:34:57,717 Atlantis - Alvin lights on, 732 00:34:57,862 --> 00:35:00,194 vent valve is open, hatches shut. 733 00:35:00,331 --> 00:35:01,764 Oxygen is on. 734 00:35:01,899 --> 00:35:03,298 Tracking is on. 735 00:35:03,434 --> 00:35:04,924 8.1 . 736 00:35:05,069 --> 00:35:07,469 Permission to dive When the sWimmers are clear. 737 00:35:08,339 --> 00:35:10,603 Clear to dive When sWimmers are clear. 738 00:35:10,741 --> 00:35:13,039 Roger. Alvin diving. 739 00:35:27,959 --> 00:35:29,893 Read off Target 1 740 00:35:30,027 --> 00:35:34,794 First target is 34 60 46 42. 741 00:35:34,932 --> 00:35:37,127 OK, What's the landing target? 742 00:35:41,973 --> 00:35:45,465 The sun's rays can't penetrate far into the Water. 743 00:35:45,610 --> 00:35:49,137 Eventually the last of the daylight Will fade aWay. 744 00:35:50,381 --> 00:35:52,849 The sub is free falling and Matt and Susan 745 00:35:52,984 --> 00:35:55,316 drop at a rate of 30 metres a minute 746 00:35:55,453 --> 00:35:58,513 doWn into the darkness. 747 00:36:00,458 --> 00:36:02,050 lf they could see Where they Were heading, 748 00:36:02,193 --> 00:36:05,594 the vieW Would take their breath aWay. 749 00:36:14,906 --> 00:36:16,999 1 700 metres beloW, 750 00:36:17,141 --> 00:36:19,302 the valley at the centre of the mid Atlantic ridge 751 00:36:19,443 --> 00:36:21,968 stretches out before them. 752 00:36:43,367 --> 00:36:44,959 Atlantis-Alvin. Depth? 753 00:36:45,102 --> 00:36:47,229 16 23, 100 off the bottom. 754 00:36:47,371 --> 00:36:49,464 l'll call you When We get there. 755 00:36:51,776 --> 00:36:54,210 l'm getting ready to release my first Weight. 756 00:36:57,215 --> 00:36:58,512 OK, one Weight aWay, 757 00:36:58,649 --> 00:37:00,446 listen and you might hear it. 758 00:37:01,185 --> 00:37:04,154 Didn't hear it, but l saW it in the camera. 759 00:37:05,389 --> 00:37:07,289 And that should sloW our descent rate. 760 00:37:07,425 --> 00:37:10,553 We're doWn to 60 metres up off the bottom. 761 00:37:15,967 --> 00:37:18,197 Bottom's in sight. 762 00:37:18,336 --> 00:37:19,303 Atlantis-Alvin. 763 00:37:19,437 --> 00:37:23,134 Depth 1 7 12 on the bottom. 764 00:37:23,274 --> 00:37:26,300 Roger that. 765 00:37:26,444 --> 00:37:28,002 OK l've seen some structures 766 00:37:28,145 --> 00:37:29,669 that looked like maybe this is at the edge 767 00:37:29,814 --> 00:37:30,803 of a lava field 768 00:37:30,948 --> 00:37:34,577 and l see drain back features. l've seen some collapses. 769 00:37:34,719 --> 00:37:36,584 That's good. OK. We might be on the edge 770 00:37:36,721 --> 00:37:39,019 of a lava lake field. 771 00:37:41,325 --> 00:37:42,292 Oh yes, 772 00:37:42,426 --> 00:37:44,690 l'm going past some lava pilloWs on my side. 773 00:37:44,829 --> 00:37:48,026 Oh yeah, oh here it's beautiful. 774 00:37:54,272 --> 00:37:55,705 Alvin has landed in the heart 775 00:37:55,840 --> 00:37:57,569 of the mid Atlantic ridge - 776 00:37:57,708 --> 00:38:01,576 the place Where the Earth's crust is being created. 777 00:38:03,514 --> 00:38:05,744 This is a lava lake Where submarine floWs 778 00:38:05,883 --> 00:38:09,910 of lava have become tWisted into dramatic shapes. 779 00:38:30,675 --> 00:38:33,576 The rock here is just a feW hundred years old. 780 00:38:33,711 --> 00:38:37,238 The sharp pillars have not been softened by time. 781 00:38:45,890 --> 00:38:48,381 The submersible's journey across the lava lake 782 00:38:48,526 --> 00:38:50,118 takes it betWeen the three peaks 783 00:38:50,261 --> 00:38:53,458 of the Lucky Strike volcano. 784 00:38:57,835 --> 00:38:58,961 At this depth the only light 785 00:38:59,103 --> 00:39:00,832 comes from the submersible itself 786 00:39:00,971 --> 00:39:04,737 as it finds its Way along the rugged terrain. 787 00:39:09,213 --> 00:39:11,943 Oh Well, What do l see here. 788 00:39:13,050 --> 00:39:14,278 l see some White. 789 00:39:14,418 --> 00:39:15,214 Something White? 790 00:39:15,353 --> 00:39:17,514 What do you see out of the port WindoW? 791 00:39:17,655 --> 00:39:22,251 l see What looks like some hydro thermal staining to me. 792 00:39:23,627 --> 00:39:25,754 Matt and Susan have detected staining 793 00:39:25,896 --> 00:39:27,454 deposited by hot springs 794 00:39:27,598 --> 00:39:30,032 called hydro-thermal vents. 795 00:39:30,167 --> 00:39:32,294 When volcanoes and Water mix hot springs 796 00:39:32,436 --> 00:39:34,336 are an inevitable result 797 00:39:34,472 --> 00:39:35,996 and the presence of these deep sea vents 798 00:39:36,140 --> 00:39:38,040 had been predicted. 799 00:39:38,175 --> 00:39:39,642 But the reality turned out to be 800 00:39:39,777 --> 00:39:44,214 even more startling than the Wildest predictions. 801 00:39:58,162 --> 00:40:01,393 The first time Alvin came across a black smoker 802 00:40:01,532 --> 00:40:04,433 it Was piloted by Dudley Foster. 803 00:40:04,969 --> 00:40:07,062 lt Was like a steam locomotive 804 00:40:07,204 --> 00:40:10,264 billoWing smoke out of the bottom. 805 00:40:10,408 --> 00:40:11,966 And l couldn't imagine What it Was, 806 00:40:12,109 --> 00:40:13,940 l Was just you knoW, floundered 807 00:40:14,078 --> 00:40:16,342 and floored by this. 808 00:40:17,081 --> 00:40:18,548 We stuck the temperature probe 809 00:40:18,682 --> 00:40:19,808 into this plume of Water 810 00:40:19,950 --> 00:40:21,349 and the probe could only measure up 811 00:40:21,485 --> 00:40:23,749 to 30 degrees and that pegged immediately, 812 00:40:23,888 --> 00:40:25,651 so l moved the probe out of that 813 00:40:25,790 --> 00:40:27,087 and l could see the end of the probe 814 00:40:27,224 --> 00:40:30,318 had turned black and it looked, l thought Well, 815 00:40:30,461 --> 00:40:33,396 this is kind of the dust Whatever the smokey stuff is 816 00:40:33,531 --> 00:40:34,998 and When We got back to the surface 817 00:40:35,132 --> 00:40:36,463 We found that the PVC rod 818 00:40:36,600 --> 00:40:38,659 had actually been burned in the feW seconds 819 00:40:38,803 --> 00:40:39,997 that it Was in this Water. 820 00:40:40,137 --> 00:40:43,698 That Was our first clue that this Was extremely hot. 821 00:40:44,241 --> 00:40:45,037 Oh man, 822 00:40:45,176 --> 00:40:46,370 did l open up a nice hole. Look at that. 823 00:40:46,510 --> 00:40:47,636 That is sWeet. 824 00:40:47,778 --> 00:40:48,802 That's a big one. l like that. 825 00:40:48,946 --> 00:40:52,313 Oh, right. That should be an easy one to sample. 826 00:40:52,450 --> 00:40:54,941 Once We'd discovered that hoW hot these hydro- 827 00:40:55,085 --> 00:40:56,746 thermal vents could get 828 00:40:56,887 --> 00:40:59,378 We became concerned about the impact 829 00:40:59,523 --> 00:41:00,956 on the submersible, particularly 830 00:41:01,091 --> 00:41:03,457 since the vieW ports are made out of plastic 831 00:41:03,594 --> 00:41:05,061 and at the sort of depths We're Working, 832 00:41:05,196 --> 00:41:08,495 they could start to lose their strength 833 00:41:08,632 --> 00:41:10,463 in about 90 degrees C. 834 00:41:10,601 --> 00:41:15,629 18, 7 4, 216, 241 , 256, 835 00:41:15,773 --> 00:41:22,804 303, 291 , 321 , 321 ... 836 00:41:22,947 --> 00:41:24,972 The Water pumping out of this vent 837 00:41:25,115 --> 00:41:29,449 is at 321 degrees Centigrade. 838 00:41:29,587 --> 00:41:32,249 We Worked very close to these structures 839 00:41:32,389 --> 00:41:34,186 because We reach out With the manipulator 840 00:41:34,325 --> 00:41:36,623 and sample them, put probes in them 841 00:41:36,760 --> 00:41:38,853 and do a lot of Work around them, 842 00:41:38,996 --> 00:41:40,657 but frequently there are several 843 00:41:40,798 --> 00:41:42,629 and you can easily bump up next to one 844 00:41:42,766 --> 00:41:45,826 and several times the fibreglass skin 845 00:41:45,970 --> 00:41:48,268 on the submarine has actually been burned. 846 00:41:48,405 --> 00:41:49,497 Come back With several layers 847 00:41:49,640 --> 00:41:51,471 of glass burned aWay 848 00:41:51,609 --> 00:41:54,476 and the paint charred black. 849 00:41:56,947 --> 00:42:00,348 lt's a hazardous environment for the sub and its creW, 850 00:42:00,484 --> 00:42:04,386 but no-one had imagined it could also support life. 851 00:42:09,894 --> 00:42:11,725 OK, Let's see if We could smoke some of these shrimp. 852 00:42:11,862 --> 00:42:13,659 These look great. 853 00:42:14,732 --> 00:42:16,427 Yes l... 854 00:42:17,501 --> 00:42:18,866 Are you, are you getting any? 855 00:42:19,003 --> 00:42:22,131 l'm Working on it to get some of this stuff in there, 856 00:42:22,273 --> 00:42:23,900 l'm getting some bacterial mat. 857 00:42:24,041 --> 00:42:25,736 OK Well keep trying on the shrimp. 858 00:42:25,876 --> 00:42:27,537 Shrimp are pretty resilient. 859 00:42:27,678 --> 00:42:28,838 They're saying ''oh, no, no. 860 00:42:28,979 --> 00:42:29,946 l'm not going in there''. l knoW. 861 00:42:30,080 --> 00:42:32,640 They can move around pretty fast. 862 00:42:32,783 --> 00:42:35,684 Get in there! Get in there! Get in there! 863 00:42:36,153 --> 00:42:39,350 OK. Well, hoWever many We've got, 864 00:42:39,490 --> 00:42:41,890 maybe We should call it quits. 865 00:42:42,026 --> 00:42:45,257 l'll look up our range and bearing to our next site. 866 00:42:47,231 --> 00:42:48,721 Shrimp, mussels and fish 867 00:42:48,866 --> 00:42:52,063 have all been found thriving around the smokers. 868 00:42:52,202 --> 00:42:53,726 They survive Where most scientists 869 00:42:53,871 --> 00:42:55,930 expected life to be impossible 870 00:42:56,073 --> 00:42:57,165 in the pitch dark, 871 00:42:57,308 --> 00:42:58,434 cut off from the sun's energy, 872 00:42:58,576 --> 00:43:02,239 Which fuels every other echo system on the planet. 873 00:43:03,948 --> 00:43:06,382 At the bottom of this complex Web of life, 874 00:43:06,517 --> 00:43:10,317 supporting the Whole thing, are bacteria. 875 00:43:10,454 --> 00:43:13,252 Those bacteria feed off the rich cocktail of chemicals 876 00:43:13,390 --> 00:43:16,655 speWing out in the superheated Water. 877 00:43:24,501 --> 00:43:26,765 All these living things are totally dependent 878 00:43:26,904 --> 00:43:29,998 on the earth's oWn energy. 879 00:43:37,247 --> 00:43:39,545 Locked up in the rocks of South Africa 880 00:43:39,683 --> 00:43:41,651 is evidence that this strange World 881 00:43:41,785 --> 00:43:44,652 has existed for billions of years. 882 00:43:45,522 --> 00:43:47,217 Well here We are in Barberton mountain land 883 00:43:47,358 --> 00:43:48,620 Walking on some of the oldest rocks 884 00:43:48,759 --> 00:43:51,193 that have ever been found on earth. 885 00:43:51,328 --> 00:43:53,125 And the particular rocks that l am Walking on 886 00:43:53,263 --> 00:43:55,060 are ocean floor rocks, 887 00:43:55,199 --> 00:43:58,430 very old ocean floor. 888 00:43:58,569 --> 00:44:00,196 And We noW knoW that this ocean floor 889 00:44:00,337 --> 00:44:02,862 and all these rocks everywhere around us here 890 00:44:03,007 --> 00:44:05,771 are 3.5 billion years old. 891 00:44:09,613 --> 00:44:10,807 Come up here. 892 00:44:10,948 --> 00:44:12,882 This is Where the rocks have been cracked open in tWo. 893 00:44:13,017 --> 00:44:14,951 Look this hand here fits 894 00:44:15,085 --> 00:44:16,643 With that hand over there. 895 00:44:16,787 --> 00:44:18,948 Only We can see this pilloWs, 896 00:44:19,089 --> 00:44:22,320 these belts in cross section, very nicely. 897 00:44:22,459 --> 00:44:26,361 This is very characteristic of hoW lava forms 898 00:44:26,497 --> 00:44:28,226 or the sort of shapes lava forms 899 00:44:28,365 --> 00:44:30,356 as it hits the ocean floor. 900 00:44:31,602 --> 00:44:33,695 Underwater eruptions are very different 901 00:44:33,837 --> 00:44:36,067 to lava floWs on land. 902 00:44:36,206 --> 00:44:38,504 Lava erupting into Water rapidly cools, 903 00:44:38,642 --> 00:44:40,337 forming a skin. 904 00:44:40,477 --> 00:44:42,445 As more lava Wells up from beloW 905 00:44:42,579 --> 00:44:44,774 it continuously pushes out neW buds 906 00:44:44,915 --> 00:44:46,177 onto the ocean floor 907 00:44:46,316 --> 00:44:49,444 like pilloWs of solidifying rock. 908 00:44:54,258 --> 00:44:55,282 Anywhere you go today 909 00:44:55,426 --> 00:44:56,723 you see these kind of fossils. 910 00:44:56,860 --> 00:44:59,488 With these shapes you knoW you're Walking 911 00:44:59,630 --> 00:45:03,088 on rocks that Were once covered by, by Water. 912 00:45:03,233 --> 00:45:04,700 And like the oceans today, 913 00:45:04,835 --> 00:45:08,498 the ancient oceans also had black smokers. 914 00:45:08,639 --> 00:45:10,766 Three and a half billion years ago, 915 00:45:10,908 --> 00:45:14,105 hot Water streamed out of this rock. 916 00:45:14,244 --> 00:45:16,576 The mineral deposits are not the only traces 917 00:45:16,714 --> 00:45:18,909 the smokers left behind. 918 00:45:19,049 --> 00:45:20,607 And When We look at these flinty rocks 919 00:45:20,751 --> 00:45:22,651 in detail under the microscope 920 00:45:22,786 --> 00:45:24,947 We find very ancient bacteria. 921 00:45:25,089 --> 00:45:28,217 So that l think makes it a very solid case 922 00:45:28,358 --> 00:45:30,622 for the sort of hypothesis that are hanging around 923 00:45:30,761 --> 00:45:33,286 that make people believe, 924 00:45:33,430 --> 00:45:35,364 perhaps, these kind of associations, 925 00:45:35,499 --> 00:45:37,160 the pilloW basalts and the black smokers 926 00:45:37,301 --> 00:45:39,064 are the sort of areas, the niches, 927 00:45:39,203 --> 00:45:41,364 Were life might have originated. 928 00:45:44,308 --> 00:45:47,368 Could it be that life on our planet first evolved 929 00:45:47,511 --> 00:45:49,638 at a hydro-thermal vent? 930 00:45:52,382 --> 00:45:55,146 On board Atlantis, biologists are studying the bacteria 931 00:45:55,285 --> 00:45:57,753 from black smokers to see hoW closely 932 00:45:57,888 --> 00:46:00,948 they are related to the earliest forms of life. 933 00:46:01,091 --> 00:46:03,218 Judy Which sample are We Working With? 934 00:46:03,360 --> 00:46:04,622 We'll start With the slurry 935 00:46:04,762 --> 00:46:05,626 that's been settling... 936 00:46:05,763 --> 00:46:08,823 Analysis of their DNA shoWs the deep sea bacteria 937 00:46:08,966 --> 00:46:10,627 are the most primitive forms of life 938 00:46:10,768 --> 00:46:13,168 on the evolutionary tree. 939 00:46:14,238 --> 00:46:17,605 These bacteria really could be the direct descendants 940 00:46:17,741 --> 00:46:20,301 of the first living things on Earth. 941 00:46:26,183 --> 00:46:27,810 The Work on the evolution of life 942 00:46:27,951 --> 00:46:30,681 all stemmed from a simple observation; 943 00:46:30,821 --> 00:46:34,120 the matching of tWo distant coastlines. 944 00:46:37,427 --> 00:46:38,826 ln the last feW decades, 945 00:46:38,962 --> 00:46:40,987 the deep ocean has begun to lay bare 946 00:46:41,131 --> 00:46:43,122 its secrets to science. 947 00:46:43,267 --> 00:46:44,928 We've finally come to understand 948 00:46:45,068 --> 00:46:48,094 hoW truly dynamic our planet is 949 00:46:48,238 --> 00:46:52,299 and hoW the sea floor is being continuously remade. 950 00:47:01,018 --> 00:47:03,509 Perhaps the most fascinating discovery of them all 951 00:47:03,654 --> 00:47:06,179 is the links We've found betWeen the earth's activity 952 00:47:06,323 --> 00:47:08,655 and the origin of life. 953 00:47:09,393 --> 00:47:12,021 The energy Which fuelled the first living thing 954 00:47:12,162 --> 00:47:14,289 is the same energy that is still remaking 955 00:47:14,431 --> 00:47:16,490 the surface of our planet. 956 00:47:19,870 --> 00:47:20,996 But if you think about it, 957 00:47:21,138 --> 00:47:22,901 there's a problem. 958 00:47:23,040 --> 00:47:24,098 For billions of years, 959 00:47:24,241 --> 00:47:26,505 neW sea floor has been continuously produced 960 00:47:26,643 --> 00:47:28,543 at mid-ocean ridges - 961 00:47:28,679 --> 00:47:30,010 so, unless the earth's been getting 962 00:47:30,147 --> 00:47:32,843 steadily bigger over all that time - 963 00:47:32,983 --> 00:47:34,473 there must be someWhere on the planet 964 00:47:34,618 --> 00:47:36,108 Where crust is being devoured 965 00:47:36,253 --> 00:47:39,188 as fast as it's being made. 966 00:47:39,857 --> 00:47:41,085 Solving that paradox 967 00:47:41,225 --> 00:47:43,159 Will take us in our next programme 968 00:47:43,293 --> 00:47:45,887 to the volcanoes ringing the Pacific 969 00:47:46,029 --> 00:47:48,088 and also explain hoW the land 970 00:47:48,232 --> 00:47:50,996 We live on came into being.