1 00:00:03,800 --> 00:00:05,380 ALARM RINGS 2 00:00:05,380 --> 00:00:08,620 Every morning when you wake up and start your day, 3 00:00:08,620 --> 00:00:12,740 you might think the world around you hasn't changed much since yesterday, 4 00:00:12,740 --> 00:00:14,020 but you'd be wrong. 5 00:00:15,500 --> 00:00:18,220 Because while we're going about our normal day, 6 00:00:18,220 --> 00:00:22,220 our Earth is altering itself in ways we couldn't even imagine. 7 00:00:29,220 --> 00:00:32,820 We're going to spend 24 hours with our planet, 8 00:00:32,820 --> 00:00:37,020 to watch what it's really getting up to in the course of an average day. 9 00:00:38,060 --> 00:00:41,900 Across the globe, a new breed of scientists are showing us our home 10 00:00:41,900 --> 00:00:43,780 as we've never seen it before - 11 00:00:43,780 --> 00:00:46,780 an Earth that is constantly reinventing itself. 12 00:00:46,780 --> 00:00:48,660 Things are always active. 13 00:00:48,660 --> 00:00:51,900 The Earth is really living and breathing all the time. 14 00:00:51,900 --> 00:00:56,940 Every second of every day, it's growing, shrinking and moving, 15 00:00:57,140 --> 00:01:00,340 and each change has surprising consequences for our lives. 16 00:01:01,660 --> 00:01:04,220 Every hour, the Earth is making mountains of new rock... 17 00:01:06,940 --> 00:01:09,660 Never gives up, just never stops. 18 00:01:09,660 --> 00:01:12,540 ..in a way that is crucial to our daily survival. 19 00:01:14,020 --> 00:01:17,300 By the time you've stopped for lunch, tonnes of dust from 20 00:01:17,300 --> 00:01:20,500 the Sahara will have landed in a faraway ocean. 21 00:01:21,660 --> 00:01:23,940 That dust is still coming. 22 00:01:23,940 --> 00:01:26,300 Every day, yeah. All the time, every day. 23 00:01:26,300 --> 00:01:30,180 Dust from a desert that will help give us the air we breathe. 24 00:01:32,540 --> 00:01:34,420 And before we go to sleep, 25 00:01:34,420 --> 00:01:37,780 glaciers will have changed the face of the planet, 26 00:01:37,780 --> 00:01:41,060 and helped trigger a mass movement of animal life. 27 00:01:42,020 --> 00:01:43,700 So, this is enormous. 28 00:01:43,700 --> 00:01:46,580 This is like the largest migration on Earth. 29 00:01:46,580 --> 00:01:51,100 In this programme we'll reveal the myriad different ways 30 00:01:51,100 --> 00:01:54,460 in which the planet transforms itself every single day... 31 00:01:54,460 --> 00:01:55,820 Whoa! 32 00:01:56,940 --> 00:02:01,620 ..and how they come together to make life on our world possible. 33 00:02:01,620 --> 00:02:06,660 You can forget about the Earth taking millions of years to change, 34 00:02:06,820 --> 00:02:09,460 because it is changing as fast as we are. 35 00:02:22,020 --> 00:02:23,700 Quite a lot can change in a day. 36 00:02:24,740 --> 00:02:28,100 Families can grow, you can move house, 37 00:02:28,100 --> 00:02:30,620 fortunes can be won or lost. 38 00:02:32,020 --> 00:02:35,820 But a single day can be just as transformative for our planet. 39 00:02:38,380 --> 00:02:41,380 Even something we think of as solid and unchanging, 40 00:02:41,380 --> 00:02:45,020 like the land we stand on - it's not. 41 00:02:47,740 --> 00:02:51,140 Across the world, land is being made and rearranged 42 00:02:51,140 --> 00:02:54,020 on an extraordinary scale, on a daily basis. 43 00:03:14,700 --> 00:03:18,380 And if you live here in Stromboli, off the west coast of Italy, 44 00:03:18,380 --> 00:03:20,580 you can see it happening. 45 00:03:20,580 --> 00:03:23,860 Here, they wake up to a new view every morning. 46 00:03:42,220 --> 00:03:46,380 Stromboli's almost continual eruptions might shake up the locals, 47 00:03:46,380 --> 00:03:50,660 but scientists are drawn here despite the obvious dangers. 48 00:03:50,660 --> 00:03:53,580 Although as a geologist I shouldn't really be nervous, there's still 49 00:03:53,580 --> 00:03:57,340 something about being so close to so much heat and energy. 50 00:03:58,380 --> 00:04:01,260 For geologists Chris Jackson and Giuseppe DeRosa, 51 00:04:01,260 --> 00:04:04,940 this is the place to study what volcanoes are really capable of. 52 00:04:06,060 --> 00:04:07,700 You feel all of the ash raining down 53 00:04:07,700 --> 00:04:09,740 from that last eruption now, can't you? Yes. 54 00:04:09,740 --> 00:04:11,820 Gosh! HE LAUGHS 55 00:04:11,820 --> 00:04:16,860 Wow. A giant eruption there, lots and lots of lava coming out. 56 00:04:17,060 --> 00:04:19,900 Huge volumes just being blown out of the top. 57 00:04:21,900 --> 00:04:26,900 Lava that, in fact, plays a vital role for all of us on the planet, 58 00:04:26,900 --> 00:04:30,140 because this lava is about to become land. 59 00:04:35,740 --> 00:04:40,380 It's amazing seeing these car-sized lava bombs being hurled out of 60 00:04:40,380 --> 00:04:41,580 this volcano. 61 00:04:41,580 --> 00:04:45,700 Magma bursting to the surface, becoming lava, becoming rock, 62 00:04:45,700 --> 00:04:47,340 and ultimately becoming land. 63 00:04:49,940 --> 00:04:51,940 You can see all down the flanks, 64 00:04:51,940 --> 00:04:54,580 that orange glow of lava which has just been kicked out. 65 00:04:56,340 --> 00:05:00,020 Over the course of just 24 hours, this volcano can throw out 66 00:05:00,020 --> 00:05:03,500 enough lava to fill 80 Olympic-size swimming pools. 67 00:05:09,260 --> 00:05:12,300 Volcanoes build land in different ways, 68 00:05:12,300 --> 00:05:14,500 depending on the type of stuff that's coming out. 69 00:05:16,460 --> 00:05:19,140 Lots of different minerals in here, this green colour's... 70 00:05:19,140 --> 00:05:20,580 Yes, this is all living. Yes. 71 00:05:22,220 --> 00:05:25,500 The mineral content of the lava makes it behave in different ways. 72 00:05:26,540 --> 00:05:28,140 Basically, there are two types. 73 00:05:30,020 --> 00:05:34,300 The first, lava low in a mineral called silica 74 00:05:34,300 --> 00:05:37,540 that can build big areas of land quickly - 75 00:05:37,540 --> 00:05:38,700 the runny stuff. 76 00:05:39,980 --> 00:05:44,780 It very quickly runs all the way down the sides and builds new land 77 00:05:44,780 --> 00:05:46,020 all the way around the edges. 78 00:05:48,900 --> 00:05:52,540 On the islands of Hawaii, the runny stuff spills into the ocean 79 00:05:52,540 --> 00:05:53,860 and turns to rock, 80 00:05:53,860 --> 00:05:58,220 creating an average of six square metres of new land every hour. 81 00:05:59,980 --> 00:06:01,980 Half a tennis court in a day. 82 00:06:05,540 --> 00:06:07,460 So, you have the runny lava, 83 00:06:07,460 --> 00:06:09,980 but there's also the sticky stuff... 84 00:06:09,980 --> 00:06:11,900 It's too sticky to even come out. 85 00:06:11,900 --> 00:06:14,220 ..which has a higher silica content 86 00:06:14,220 --> 00:06:17,180 and builds land in a more explosive way. 87 00:06:17,180 --> 00:06:18,380 LOUD EXPLOSION 88 00:06:19,540 --> 00:06:22,580 Like, some of the things that are coming out right now, 89 00:06:22,580 --> 00:06:26,700 these bombs of lava rolling all the way down the sides of the volcano 90 00:06:26,700 --> 00:06:28,500 and building the crater itself. 91 00:06:31,100 --> 00:06:35,820 Over thousands of years, the sticky lava erupting from this volcano 92 00:06:35,820 --> 00:06:38,300 built this island up out of the sea, 93 00:06:38,300 --> 00:06:40,540 and formed its classic cone shape. 94 00:06:43,100 --> 00:06:47,900 But sometimes, a volcanic island can appear almost overnight. 95 00:06:47,900 --> 00:06:52,900 In 2014, this volcano in Tonga sprang out of the Pacific Ocean, 96 00:06:53,700 --> 00:06:56,940 building 60,000 square metres per day. 97 00:06:57,980 --> 00:07:00,860 Right now, as you're watching this, 98 00:07:00,860 --> 00:07:05,860 between 10 and 20 volcanoes are erupting, spraying out new land 99 00:07:06,260 --> 00:07:09,140 across the surface of the Earth, 100 00:07:09,140 --> 00:07:12,380 making a real difference not just in millennia, 101 00:07:12,380 --> 00:07:13,620 but in minutes. 102 00:07:17,540 --> 00:07:22,500 In fact, in just one hour, the time it takes most of us to get out 103 00:07:22,740 --> 00:07:26,940 of the house, it's estimated the planet has made 104 00:07:26,940 --> 00:07:29,740 3 million cubic metres of lava. 105 00:07:32,260 --> 00:07:36,100 Enough to build an island 200 metres tall. 106 00:07:39,660 --> 00:07:44,260 Without this process, the people of Stromboli wouldn't have a home. 107 00:07:44,260 --> 00:07:47,660 But then again, neither would we. 108 00:07:50,020 --> 00:07:54,780 Every day, you have got volcanic activity creating new land. 109 00:07:57,020 --> 00:07:59,500 But every day, you also have wind 110 00:07:59,500 --> 00:08:02,980 and water eroding land away. 111 00:08:06,380 --> 00:08:11,300 Now, if volcanic activity didn't create land as quickly as it does, 112 00:08:11,780 --> 00:08:16,380 then erosion would win that battle and the world would be left 113 00:08:16,380 --> 00:08:18,580 as one giant ocean. 114 00:08:22,700 --> 00:08:26,420 So, volcanic activity keeps us all above water, 115 00:08:26,420 --> 00:08:30,540 but it's only possible because of the heat that's generated 116 00:08:30,540 --> 00:08:31,780 deep beneath our feet. 117 00:08:35,660 --> 00:08:38,180 We have two sources of heat in the Earth - 118 00:08:38,180 --> 00:08:41,300 primordial heat, that's coming from the core, white hot, 119 00:08:41,300 --> 00:08:45,420 6,000-7,000 degrees Celsius, so, similar to the surface of the sun. 120 00:08:45,420 --> 00:08:49,580 Outside of that region, here in the mantle and in the crust, 121 00:08:49,580 --> 00:08:52,820 we also have heat that's being produced by radioactive decay. 122 00:08:54,300 --> 00:08:59,300 This heat produced by radioactive decay drives volcanic activity 123 00:08:59,300 --> 00:09:01,860 and is best explained by popcorn. 124 00:09:03,060 --> 00:09:05,620 A heavy element like uranium 125 00:09:05,620 --> 00:09:09,580 becomes lighter by emitting a particle from its atomic nucleus. 126 00:09:09,580 --> 00:09:13,020 As it does that, a burst of energy is released in the form of heat 127 00:09:13,020 --> 00:09:16,380 and it is that heat that drives the geological processes deep beneath 128 00:09:16,380 --> 00:09:18,580 our feet and at the Earth's surface. 129 00:09:19,700 --> 00:09:21,060 Ooh! 130 00:09:22,460 --> 00:09:26,060 Every time a heavy atom decays into a lighter one, 131 00:09:26,060 --> 00:09:28,300 there's another burst of energy. 132 00:09:28,300 --> 00:09:31,700 It's the very same process that we use to create nuclear energy. 133 00:09:33,500 --> 00:09:35,460 And it's everywhere. 134 00:09:35,460 --> 00:09:39,620 The smaller dark spots on this map are nuclear power plants. 135 00:09:39,620 --> 00:09:41,060 Everywhere else, 136 00:09:41,060 --> 00:09:45,540 radioactivity is coming from atoms decaying underground. 137 00:09:45,540 --> 00:09:47,940 And it all adds up. 138 00:09:47,940 --> 00:09:52,300 In just three hours, before you've even had your mid-morning coffee, 139 00:09:52,300 --> 00:09:56,300 the Earth has generated heat energy from radioactive decay 140 00:09:56,300 --> 00:10:00,500 equivalent to 4,000 Hiroshima bombs. 141 00:10:00,500 --> 00:10:03,540 That's about one every three seconds. 142 00:10:15,780 --> 00:10:20,660 So, every minute of every day, the Earth changes from within. 143 00:10:20,660 --> 00:10:24,700 But once land is made, it doesn't stay put. 144 00:10:24,700 --> 00:10:29,740 As we continue on our day, it's time to see how the land is being warped 145 00:10:29,820 --> 00:10:32,500 and moved right under our noses. 146 00:10:36,940 --> 00:10:39,900 First, we have to look to the water. 147 00:10:39,900 --> 00:10:41,980 In particular, the tides. 148 00:10:41,980 --> 00:10:46,060 We're all familiar with sea levels going up and down twice a day. 149 00:10:46,060 --> 00:10:49,100 Well, every 12 hours 25 minutes, to be precise. 150 00:10:49,100 --> 00:10:53,180 But what's less obvious is that this process is changing the shape of 151 00:10:53,180 --> 00:10:56,380 the planet, and it's all caused by the moon. 152 00:11:19,100 --> 00:11:22,220 Here in the Amazon, this shape change is so dramatic, 153 00:11:22,220 --> 00:11:23,820 you can actually see it, 154 00:11:23,820 --> 00:11:26,460 and they've even given it a name... 155 00:11:30,900 --> 00:11:32,140 ..the Pororoca. 156 00:11:42,140 --> 00:11:46,860 Pororoca, meaning great roar, is in fact a tidal bore. 157 00:11:46,860 --> 00:11:50,540 When the tides are at their highest, the water rushes into this stretch 158 00:11:50,540 --> 00:11:55,100 of river so fast, it creates a wave large enough to surf, 159 00:11:55,100 --> 00:11:56,220 and they do. 160 00:12:22,700 --> 00:12:23,980 Woohoo! 161 00:12:30,820 --> 00:12:33,940 Other than the piranhas and hidden logs in the water, 162 00:12:33,940 --> 00:12:35,900 this is perfectly safe. 163 00:12:55,580 --> 00:12:58,900 But in fact, it's not just the water that's getting pulled out 164 00:12:58,900 --> 00:13:01,140 of shape by the moon. 165 00:13:01,140 --> 00:13:05,580 We can't forget about the other 29% of the Earth's surface. 166 00:13:05,580 --> 00:13:08,180 You know, the stuff we walk on. 167 00:13:10,660 --> 00:13:14,140 Every person knows that there are tides in the ocean, but what many 168 00:13:14,140 --> 00:13:18,500 people don't realise is that the moon also causes tides in the Earth, 169 00:13:18,500 --> 00:13:20,660 so what are called solid earth tides. 170 00:13:22,460 --> 00:13:26,580 We can now prove that the moon moves rock as well as water, 171 00:13:26,580 --> 00:13:31,100 causing a tidal bulge in the very land we stand on, which is 172 00:13:31,100 --> 00:13:33,060 up to 50 centimetres high. 173 00:13:34,860 --> 00:13:39,140 Solid earth tides, or rock tides, they can be measured with GPS. 174 00:13:39,140 --> 00:13:44,180 They cause the GPS station to go up or down, so we can measure 175 00:13:44,700 --> 00:13:48,860 how high the stations are rising all along the globe. 176 00:13:48,860 --> 00:13:51,780 And this is happening about twice per day. 177 00:13:51,780 --> 00:13:55,220 Which means that in about six hours' time, I'm actually 178 00:13:55,220 --> 00:13:56,780 going to be up here. 179 00:13:56,780 --> 00:13:59,420 Now, normally, I don't need an extra 50 centimetres in height, 180 00:13:59,420 --> 00:14:01,980 but I'm embracing change today, so I'm going to go with it. 181 00:14:04,580 --> 00:14:08,140 You'd think you'd notice these waves of solid earth, 182 00:14:08,140 --> 00:14:10,780 but they happen over such a huge area that they are 183 00:14:10,780 --> 00:14:12,940 imperceptible to us. 184 00:14:12,940 --> 00:14:14,860 But that doesn't mean they do not affect us. 185 00:14:16,940 --> 00:14:21,220 In fact, research suggests that earth tides can trigger earthquakes. 186 00:14:22,460 --> 00:14:26,260 If earthquake faults are really close to failing and creating 187 00:14:26,260 --> 00:14:30,180 an earthquake, then this tiny change may be enough just to tip that fault 188 00:14:30,180 --> 00:14:32,020 off to failing. 189 00:14:34,580 --> 00:14:38,340 By the end of the morning the moon's pull on the Earth has caused 190 00:14:38,340 --> 00:14:41,700 a half-metre wave of solid rock 191 00:14:41,700 --> 00:14:45,220 to travel 9,000km around the planet, 192 00:14:45,220 --> 00:14:47,980 and you hardly even felt a thing. 193 00:14:54,460 --> 00:14:57,860 The changing shape of Earth has another side effect 194 00:14:57,860 --> 00:14:59,740 you might not have clocked. 195 00:14:59,740 --> 00:15:02,260 It makes every day a bit longer. 196 00:15:03,660 --> 00:15:05,860 Let me show you what I mean, 197 00:15:05,860 --> 00:15:08,460 but I'm going to need something for this... 198 00:15:08,460 --> 00:15:11,060 Ooh! Guys, can I borrow your ball for a second? 199 00:15:13,020 --> 00:15:14,140 Handy. 200 00:15:14,140 --> 00:15:17,780 Now, this is going to represent our squashed Earth 201 00:15:17,780 --> 00:15:19,500 spinning on its axis. 202 00:15:19,500 --> 00:15:23,100 Going to need a moon, too, though. Guys, have you got anything smaller? 203 00:15:24,500 --> 00:15:25,540 Thank you. 204 00:15:25,540 --> 00:15:29,980 Now, this tidal bulge stays ever so slightly ahead of the moon 205 00:15:29,980 --> 00:15:31,060 at any one point. 206 00:15:31,060 --> 00:15:34,300 The moon is acting almost like a brake on a bicycle wheel, 207 00:15:34,300 --> 00:15:38,340 slowing down the spinning of the Earth and making our days 208 00:15:38,340 --> 00:15:40,060 ever so slightly longer. 209 00:15:43,100 --> 00:15:45,620 Throughout our morning, the moon has been slowing down 210 00:15:45,620 --> 00:15:47,500 the Earth's spin, 211 00:15:47,500 --> 00:15:52,340 with a force equivalent to 6,000 jumbo jets, 212 00:15:52,340 --> 00:15:57,300 and has caused a tidal bulge to travel through water and rock, 213 00:16:06,380 --> 00:16:09,820 What with tidal bores, earthquakes and land waves, 214 00:16:09,820 --> 00:16:13,700 you might think that the moon's influence on us isn't a great one, 215 00:16:13,700 --> 00:16:17,860 but the chances are that without it, none of us would even be here, 216 00:16:17,860 --> 00:16:21,340 because in amongst everything else that the moon does, 217 00:16:21,340 --> 00:16:24,500 it also stabilises the Earth spinning on its axis. 218 00:16:24,500 --> 00:16:27,500 Without the moon there, the Earth would be wobbling all over 219 00:16:27,500 --> 00:16:31,300 the place, which would change our seasonal relationship with the sun, 220 00:16:31,300 --> 00:16:35,220 make the climate completely different and quite possibly mean 221 00:16:35,220 --> 00:16:39,380 that the conditions never arise for complex life to evolve. 222 00:16:40,460 --> 00:16:42,380 Can we get the ball back? Oh, yeah, sorry. 223 00:16:45,220 --> 00:16:48,780 But when it comes to moving land around every day, the moon 224 00:16:48,780 --> 00:16:51,900 has nothing on the Earth itself, 225 00:16:51,900 --> 00:16:55,420 and yet our planet's work goes largely unappreciated. 226 00:16:57,140 --> 00:16:58,860 Well, we all know that feeling. 227 00:17:01,420 --> 00:17:04,980 The Earth, if it could talk, would probably agree with me, 228 00:17:04,980 --> 00:17:08,020 because one of the barely visible things that it does every single day 229 00:17:08,020 --> 00:17:12,980 may well have given birth to some of humanity's greatest civilisations. 230 00:17:21,220 --> 00:17:23,580 This is the Sahara. 231 00:17:23,580 --> 00:17:26,060 Morocco, to be precise. 232 00:17:26,060 --> 00:17:29,140 And in this part of the world, land doesn't just move, 233 00:17:29,140 --> 00:17:30,980 it can actually fly. 234 00:17:33,100 --> 00:17:37,980 It's stunning, the landscape here is peaceful and remote, 235 00:17:37,980 --> 00:17:40,380 but at the other way, it's dynamic. 236 00:17:40,380 --> 00:17:44,020 You get to experience how nature is moving every day. 237 00:17:45,100 --> 00:17:48,980 Geologist Charlie Bristow spends his time trying to figure out 238 00:17:48,980 --> 00:17:52,500 how solid earth can cross an ocean. 239 00:17:55,260 --> 00:17:58,580 The story begins on a dried-out lakebed. 240 00:17:58,580 --> 00:17:59,700 How dry? 241 00:17:59,700 --> 00:18:01,980 It's very dry. Very, very dry. 242 00:18:01,980 --> 00:18:04,820 And this isn't just any old mud. 243 00:18:04,820 --> 00:18:05,900 It's special. 244 00:18:07,660 --> 00:18:10,260 This place appears dead, there's nothing here, 245 00:18:10,260 --> 00:18:12,860 it's dried out, it's completely desiccated. 246 00:18:12,860 --> 00:18:14,180 But the lake was here 247 00:18:14,180 --> 00:18:16,820 and in the lake, there were little animals living here. 248 00:18:16,820 --> 00:18:19,820 There's something called an ostracod, a little crustacean, 249 00:18:19,820 --> 00:18:21,660 they're kind of cute little things. 250 00:18:21,660 --> 00:18:24,500 And their remains are still there, 251 00:18:24,500 --> 00:18:27,700 so within the mud, there are nutrients. 252 00:18:27,700 --> 00:18:30,660 Nutrients that are about to find themselves 253 00:18:30,660 --> 00:18:32,740 on the other side of the world. 254 00:18:38,940 --> 00:18:40,020 Hello, Veronica. 255 00:18:40,020 --> 00:18:41,780 Hello. 256 00:18:41,780 --> 00:18:43,580 I'm Veronica Llaneza. 257 00:18:43,580 --> 00:18:45,220 I'm Ramon Llaneza. 258 00:18:48,260 --> 00:18:49,700 Ready to go dive? 259 00:18:50,700 --> 00:18:55,060 We decided to take a trip to the Bahamas and it was a four-day trip 260 00:18:55,060 --> 00:18:56,780 and it was pretty amazing. 261 00:19:01,060 --> 00:19:04,500 This was not your average father and daughter day out. 262 00:19:05,940 --> 00:19:09,860 Veronica and Ramon are technical divers and were exploring 263 00:19:09,860 --> 00:19:13,860 an underwater cave system - not for the faint-hearted. 264 00:19:16,660 --> 00:19:18,740 Out of nowhere, you see this hole. 265 00:19:18,740 --> 00:19:20,180 A small hole. Yeah. 266 00:19:22,020 --> 00:19:25,460 And then it opens up to these beautiful caves 267 00:19:25,460 --> 00:19:30,380 with all of these stalactites and stalagmites and it's just beautiful. 268 00:19:30,700 --> 00:19:33,020 Alien world, an alien world. Yeah. 269 00:19:36,780 --> 00:19:39,620 Deep into the caves, something caught their eye. 270 00:19:40,540 --> 00:19:43,660 Something that didn't belong. 271 00:19:43,660 --> 00:19:46,780 Suddenly, you start to see pink. Yeah. 272 00:19:46,780 --> 00:19:47,980 And red. 273 00:19:58,940 --> 00:20:01,060 You would see this red dust. 274 00:20:04,140 --> 00:20:07,300 It's very, very fine. 275 00:20:10,100 --> 00:20:12,700 I said, "What is this, where is it coming from?" 276 00:20:17,700 --> 00:20:21,580 The answer is far from what they might have expected, 277 00:20:21,580 --> 00:20:24,340 because this is exactly the same stuff 278 00:20:24,340 --> 00:20:26,580 as Charlie Bristow was turning up 279 00:20:26,580 --> 00:20:31,580 6,500 kilometres away on his dried-out lakebed in the Sahara. 280 00:20:33,140 --> 00:20:37,620 People say, how do you know that that's from the Sahara? 281 00:20:37,620 --> 00:20:39,180 How do you know? 282 00:20:39,180 --> 00:20:43,300 A lot of geology is detective work, so in order to link the dust 283 00:20:43,300 --> 00:20:47,300 sediments from the Sahara with those that were found in the Caribbean, 284 00:20:47,300 --> 00:20:51,860 you can use a variety of rarer elements found in minute amounts. 285 00:20:51,860 --> 00:20:55,420 They're good for fingerprinting the dust and show that the dust 286 00:20:55,420 --> 00:20:58,100 that leaves Africa is the same as the dust that arrives 287 00:20:58,100 --> 00:20:59,380 in the Caribbean. 288 00:21:01,340 --> 00:21:06,300 But how does this nutrient-rich, rock-hard, sun-baked mud take off 289 00:21:07,020 --> 00:21:08,620 and fly across an ocean? 290 00:21:11,180 --> 00:21:13,820 That's what Charlie has now figured out. 291 00:21:15,340 --> 00:21:19,380 And it starts with the wind, 292 00:21:19,380 --> 00:21:23,620 which blows over this desert almost daily, 293 00:21:23,620 --> 00:21:28,340 and is strong enough to make Saharan dunes some of the fastest moving 294 00:21:28,340 --> 00:21:29,860 land on Earth. 295 00:21:31,140 --> 00:21:33,900 Wind usually blows from one direction, 296 00:21:33,900 --> 00:21:36,140 over the windward side of the dune 297 00:21:36,140 --> 00:21:39,780 and then it deposits it on the leeward side of the dune. 298 00:21:39,780 --> 00:21:43,020 This is making little avalanches down the front of the dune, 299 00:21:43,020 --> 00:21:44,860 and these dunes really motor. 300 00:21:44,860 --> 00:21:48,580 Get a really strong howling gale and that will drive the dune forwards, 301 00:21:48,580 --> 00:21:51,260 maybe over a metre in a single day. 302 00:21:51,260 --> 00:21:54,460 They're like the F1 cars of the dune world. 303 00:21:54,460 --> 00:21:56,620 Sorry. Made a bit of mess! 304 00:22:01,540 --> 00:22:06,340 Fast moving, maybe, but the sand in these dunes isn't about to take off 305 00:22:06,340 --> 00:22:09,140 and cross the Atlantic - it's too heavy. 306 00:22:09,140 --> 00:22:12,980 But it is going to help send the nutritious mud in this lakebed 307 00:22:12,980 --> 00:22:15,140 on its way west. 308 00:22:18,620 --> 00:22:23,580 Obviously, we need the wind in order to transport it, 309 00:22:24,380 --> 00:22:28,860 but it helps to have that third ingredient of the sand to sandblast 310 00:22:28,860 --> 00:22:30,940 the surface and break it up. 311 00:22:33,140 --> 00:22:35,700 Turning this mud into a fine dust. 312 00:22:37,420 --> 00:22:41,860 So, in this hand, I have got some great big chunks of lakebed, 313 00:22:41,860 --> 00:22:43,700 otherwise known as brown sugar, 314 00:22:43,700 --> 00:22:47,580 and in this hand I have got some lakebed that has been smashed up 315 00:22:47,580 --> 00:22:50,660 into tiny little bits by sandblasting. 316 00:22:50,660 --> 00:22:53,060 And me, I'm going to be the wind. 317 00:22:58,340 --> 00:23:01,620 This process of sandblasting is called saltation, 318 00:23:01,620 --> 00:23:04,660 and it's really the key behind launching 319 00:23:04,660 --> 00:23:07,460 great big chunks of earth into the sky. 320 00:23:11,660 --> 00:23:15,300 Carried by the wind, the fine nutritious dust rises 321 00:23:15,300 --> 00:23:19,060 thousands of metres into the atmosphere and then the trade wind 322 00:23:19,060 --> 00:23:21,740 carries it west across the Atlantic Ocean. 323 00:23:21,740 --> 00:23:23,900 Nasa satellites have measured that each day, 324 00:23:23,900 --> 00:23:28,980 half a million tonnes of it leaves the Sahara and heads west. 325 00:23:28,980 --> 00:23:31,820 Some of it arriving here in the Bahamas. 326 00:23:33,060 --> 00:23:37,540 That dust came and is still coming all the time, every day. 327 00:23:40,580 --> 00:23:45,100 But most flying further west, where it finally comes back to ground and 328 00:23:45,100 --> 00:23:49,740 fertilises the Amazon rainforest, the lungs of the planet. 329 00:23:51,740 --> 00:23:55,260 When you have this red dust in your hand and you think about where it's 330 00:23:55,260 --> 00:24:00,260 come from, it makes you think of who else grabbed this or touched this. 331 00:24:00,260 --> 00:24:02,780 That's just amazing and it's happening every day. 332 00:24:05,460 --> 00:24:10,460 By six hours into your day, 125,000 tonnes of dust 333 00:24:10,780 --> 00:24:14,100 will have become airborne and left the Sahara. 334 00:24:14,100 --> 00:24:16,460 And in those same six hours, 335 00:24:16,460 --> 00:24:21,300 25,000 tonnes of dust will have landed here in the Amazon. 336 00:24:30,140 --> 00:24:34,580 But this isn't the only place receiving a daily dose of nutrients 337 00:24:34,580 --> 00:24:35,620 from far away. 338 00:24:39,940 --> 00:24:43,980 And when you plot them on a map, they tell the story of humanity. 339 00:24:46,380 --> 00:24:48,340 So, I've drawn a map of the world here for you. 340 00:24:48,340 --> 00:24:51,260 It's not my best work, but I did do it upside down, 341 00:24:51,260 --> 00:24:55,300 and above here, it's almost like you've got this invisible 342 00:24:55,300 --> 00:25:00,300 conveyor belt that's depositing this stuff in northern China, 343 00:25:00,540 --> 00:25:05,500 across the great plains of America, also all over Russia, 344 00:25:05,500 --> 00:25:08,060 and in Central Europe, too. 345 00:25:08,060 --> 00:25:10,220 And it's no coincidence that these really are the places 346 00:25:10,220 --> 00:25:12,660 where some of our greatest civilisations were born. 347 00:25:12,660 --> 00:25:17,660 Because the so-called lowest soil has provided fertile ground to feed 348 00:25:18,740 --> 00:25:22,100 all these huge populations and really to power some 349 00:25:22,100 --> 00:25:24,300 of our most innovative minds. 350 00:25:25,420 --> 00:25:27,860 Oh, I didn't think you'd mind... 351 00:25:29,060 --> 00:25:30,340 OK... 352 00:25:36,940 --> 00:25:40,900 If wind can move lakebeds and feed civilisations, 353 00:25:40,900 --> 00:25:44,860 just imagine what solid ice can do. 354 00:25:44,860 --> 00:25:49,580 Glaciers can break out the nutrients from the toughest of rocks, 355 00:25:49,580 --> 00:25:53,420 a process which not only changes the landscape, but helps us 356 00:25:53,420 --> 00:25:55,340 all breathe more easily. 357 00:25:59,060 --> 00:26:01,140 They're incredibly beautiful 358 00:26:01,140 --> 00:26:06,100 and when the sun lights the ice and creates all these beautiful colours, 359 00:26:06,100 --> 00:26:09,580 it is extremely emotional, actually, to get to work with this. 360 00:26:15,780 --> 00:26:19,820 Now, when we say glacial, we tend to mean slow, 361 00:26:19,820 --> 00:26:23,780 but Heidi's measurements prove we've got glaciers wrong. 362 00:26:23,780 --> 00:26:28,460 These glaciers can move at speeds of up to 70 metres per day, 363 00:26:28,460 --> 00:26:31,500 so you can see the whole thing moving in front of you. 364 00:26:31,500 --> 00:26:32,700 This is incredible. 365 00:26:35,140 --> 00:26:38,340 So, what happens when a trillion-tonne block 366 00:26:38,340 --> 00:26:41,140 of fast-moving ice meets the land beneath? 367 00:26:41,140 --> 00:26:45,420 There's only one way to find out - get under one. 368 00:26:45,420 --> 00:26:49,900 Local guide Snorri has found a way down to the very base 369 00:26:49,900 --> 00:26:52,540 of this glacier in Iceland. 370 00:27:06,140 --> 00:27:07,580 What a cool cave! 371 00:27:08,700 --> 00:27:11,020 Quite beautiful, huh? That's awesome. 372 00:27:11,020 --> 00:27:12,620 Really stunning colours. 373 00:27:14,820 --> 00:27:16,780 I like how it changes. 374 00:27:16,780 --> 00:27:20,700 And you get these pockets that are formed by the wind, scallops. 375 00:27:20,700 --> 00:27:21,980 It's fantastic, isn't it? 376 00:27:21,980 --> 00:27:25,660 It's incredible to get access to the belly of a glacier, 377 00:27:25,660 --> 00:27:27,300 to really be inside it. 378 00:27:27,300 --> 00:27:29,380 You can feel that the glacier's alive here. 379 00:27:32,540 --> 00:27:34,260 It's cool, there are rocks inside. 380 00:27:34,260 --> 00:27:38,420 Yeah, exactly, all these little sediments and pebbles 381 00:27:38,420 --> 00:27:40,500 that are being carried by the ice, 382 00:27:40,500 --> 00:27:44,340 and glaciers are these massive conveyor belts constantly moving 383 00:27:44,340 --> 00:27:47,980 forward and reshaping the landscape around them. 384 00:27:47,980 --> 00:27:50,460 So, there's a lot happening even right now, yeah. 385 00:27:52,860 --> 00:27:57,100 And the clue to how these huge blocks of ice manage to move 386 00:27:57,100 --> 00:27:58,940 and grind down mountains 387 00:27:58,940 --> 00:28:02,620 is all around - water. 388 00:28:04,820 --> 00:28:08,300 So, ice, when it's really dry and cold, 389 00:28:08,300 --> 00:28:10,020 struggles to move, 390 00:28:10,020 --> 00:28:15,060 but as soon as you get a little bit of water at the base of the ice, 391 00:28:15,780 --> 00:28:19,860 as soon as it starts to melt, then very quickly, the ice can start 392 00:28:19,860 --> 00:28:22,340 sliding over the bedrock. 393 00:28:25,180 --> 00:28:27,740 And you can even hear the moving. 394 00:28:27,740 --> 00:28:29,420 ICE RUMBLES 395 00:28:32,020 --> 00:28:36,420 What you're listening to is an actual recording of a glacier 396 00:28:36,420 --> 00:28:38,500 as it ploughs its way through a mountain range. 397 00:28:47,300 --> 00:28:49,340 Glaciers are very noisy. 398 00:28:49,340 --> 00:28:53,260 They're very noisy because actually, they're constantly moving 399 00:28:53,260 --> 00:28:56,020 and the sounds you can hear are really special. 400 00:28:56,020 --> 00:29:00,820 It can be like gunshots, it can be the ice cracking, 401 00:29:00,820 --> 00:29:05,180 it can be the noise of the ice against the rocks, 402 00:29:05,180 --> 00:29:09,380 the kind of crashing sound, and when you're quiet for a few minutes and 403 00:29:09,380 --> 00:29:13,100 you start to really being careful and listening to these sounds, 404 00:29:13,100 --> 00:29:14,900 you realise that there's a lot happening. 405 00:29:17,060 --> 00:29:21,060 Minute by minute, these giant blocks of ice are breaking mountains 406 00:29:21,060 --> 00:29:23,860 into boulders, boulders into rocks, 407 00:29:23,860 --> 00:29:26,020 and rocks into dirt. 408 00:29:26,020 --> 00:29:31,020 A global system totalling 200,000 glaciers, a combined bulldozer 409 00:29:31,980 --> 00:29:37,060 bigger than France, working 24-hour shifts to reshape the land. 410 00:29:38,380 --> 00:29:42,740 In the space of just seven hours, if you add them all together, 411 00:29:42,740 --> 00:29:47,340 the world's glaciers grind out 2.5 million tonnes 412 00:29:47,340 --> 00:29:49,900 of minerals from mountains. 413 00:29:49,900 --> 00:29:52,140 Nothing glacial about that. 414 00:29:54,140 --> 00:29:57,180 By lunchtime, quite a lot has happened. 415 00:29:57,180 --> 00:29:59,500 A whole mountain's worth of new land 416 00:29:59,500 --> 00:30:02,460 has spewed from the bowels of the Earth. 417 00:30:02,460 --> 00:30:06,900 There's also a nutrient-rich dust cloud the size of a continent 418 00:30:06,900 --> 00:30:10,940 that has left the Sahara and is heading across the Atlantic. 419 00:30:10,940 --> 00:30:15,180 And all kinds of ice and water 420 00:30:15,180 --> 00:30:19,620 that is slowly breaking mountains down into dirt. 421 00:30:19,620 --> 00:30:21,900 And the result of all that is... 422 00:30:27,220 --> 00:30:28,340 Ta-da! 423 00:30:28,340 --> 00:30:31,740 A nourishing mix of minerals and nutrients that fuels 424 00:30:31,740 --> 00:30:35,340 a whole new wave of daily change to life. 425 00:30:35,340 --> 00:30:36,820 Cheers. 426 00:30:38,740 --> 00:30:40,580 Oh, that's disgusting. 427 00:30:46,740 --> 00:30:51,820 These are phytoplankton - a type of plant you won't have seen 428 00:30:55,180 --> 00:30:56,780 they live in the ocean. 429 00:30:56,780 --> 00:31:00,300 There, they thrive on a diet of nutrients from the Earth 430 00:31:00,300 --> 00:31:02,460 and light from the sun. 431 00:31:02,460 --> 00:31:05,540 Individually, they are small, but together, 432 00:31:05,540 --> 00:31:07,820 they have a big effect on all of us. 433 00:31:07,820 --> 00:31:10,100 Take a deep breath in... 434 00:31:11,620 --> 00:31:12,940 ..and out. 435 00:31:14,260 --> 00:31:15,500 And another - in... 436 00:31:16,820 --> 00:31:17,980 ..and out. 437 00:31:19,100 --> 00:31:23,060 One of those breaths was made by phytoplankton. 438 00:31:23,060 --> 00:31:28,020 Together, they create more oxygen than the entire Amazon rainforest. 439 00:31:29,300 --> 00:31:30,580 Trees... 440 00:31:33,180 --> 00:31:35,020 ..algae. 441 00:31:37,620 --> 00:31:41,500 Luckily for us, phytoplankton are one of the most abundant forms 442 00:31:41,500 --> 00:31:43,820 of life on our planet. 443 00:31:43,820 --> 00:31:47,340 Satellite imaging shows how they envelop pretty much 444 00:31:47,340 --> 00:31:49,580 the whole world. 445 00:31:49,580 --> 00:31:51,900 And they're growing all the time. 446 00:31:53,660 --> 00:31:57,620 In just eight hours, over 3 billion tonnes 447 00:31:57,620 --> 00:32:01,380 of phytoplankton have been added to the world's oceans. 448 00:32:01,380 --> 00:32:03,860 Gathered together in one place, 449 00:32:03,860 --> 00:32:08,060 that is a mountain of plant life 1.5 kilometres high. 450 00:32:21,020 --> 00:32:24,180 And this daily explosion of phytoplankton triggers 451 00:32:24,180 --> 00:32:28,700 one of the greatest mass movements of animals on Earth. 452 00:32:29,780 --> 00:32:33,180 This happens every day all over the world, 453 00:32:33,180 --> 00:32:36,380 but only the most determined ever get to see it. 454 00:32:37,580 --> 00:32:40,380 I'm very excited about it, because it's my first time 455 00:32:40,380 --> 00:32:42,540 diving at night. 456 00:32:42,540 --> 00:32:47,100 It's a better way for me to understand the behaviour. 457 00:32:48,220 --> 00:32:51,660 Dr Claire Paris-Limouzy is a marine biologist 458 00:32:51,660 --> 00:32:54,180 who's hitching a ride with a group of photographers. 459 00:32:54,180 --> 00:32:57,460 So, are you ready? Yeah. It's getting dark. 460 00:32:57,460 --> 00:33:00,700 They're going on what's known as a black-water dive. 461 00:33:00,700 --> 00:33:04,540 For the photographers - Linda Ianniello and Noe Sardet - 462 00:33:04,540 --> 00:33:08,020 it's a chance to capture a global feeding frenzy. 463 00:33:08,020 --> 00:33:10,620 A lot of people think we're crazy - float in the middle of nowhere. 464 00:33:10,620 --> 00:33:12,140 It's 500ft deep, 465 00:33:12,140 --> 00:33:16,260 you don't know...is there a shark out there that you can't see? 466 00:33:16,260 --> 00:33:19,940 You have to be aware and you have to be careful. 467 00:33:21,220 --> 00:33:25,940 These black-water dives are a great opportunity to capture 468 00:33:25,940 --> 00:33:28,540 video of these creatures. 469 00:33:31,180 --> 00:33:33,060 Who's going first? 470 00:33:42,020 --> 00:33:45,620 If you're afraid of the dark and afraid of the depths, 471 00:33:45,620 --> 00:33:48,140 this is definitely not for you. 472 00:33:50,140 --> 00:33:55,100 The divers are floating above 150 metres of pitch-black ocean... 473 00:33:57,700 --> 00:34:01,340 ..waiting for creatures to rise from the abyss. 474 00:34:23,100 --> 00:34:27,940 Tiny animals called zooplankton rise from the deep every night 475 00:34:27,940 --> 00:34:30,540 to feed on the phytoplankton 476 00:34:30,540 --> 00:34:33,700 that exploded in number during the day. 477 00:34:40,020 --> 00:34:44,580 When I see the plankton, this incredible colour and light 478 00:34:44,580 --> 00:34:49,500 and movement and all the energy that is there, it's extraordinary. 479 00:34:56,820 --> 00:34:59,020 At first, you're looking around and you don't know 480 00:34:59,020 --> 00:35:02,300 where to start. There's all this plankton flying around, 481 00:35:02,300 --> 00:35:04,260 floating around in the water column, 482 00:35:04,260 --> 00:35:06,860 and they're all there to feed. 483 00:35:06,860 --> 00:35:09,340 It's challenging. It's not easy photography, 484 00:35:09,340 --> 00:35:11,340 but it's worth it. 485 00:35:12,540 --> 00:35:17,460 This immense cloud of zooplankton is made of everything from 486 00:35:17,460 --> 00:35:21,780 larval forms of larger animals, like squid and crabs and rays, 487 00:35:21,780 --> 00:35:24,820 to fully grown creatures, like sea angels. 488 00:35:26,060 --> 00:35:27,940 This is my favourite shot. 489 00:35:27,940 --> 00:35:31,460 Very rare. It's a paper nautilus, also called an argonaut. 490 00:35:31,460 --> 00:35:32,940 You must have been excited. 491 00:35:32,940 --> 00:35:35,900 I was very excited. I chased it to 84 feet 492 00:35:35,900 --> 00:35:38,580 and this is a typical shot it wanted to give me, 493 00:35:38,580 --> 00:35:40,260 which is a butt shot! 494 00:35:40,260 --> 00:35:43,500 I think these animals are deep dwellers, 495 00:35:43,500 --> 00:35:46,940 so they have migrated hundreds of metres. 496 00:35:52,940 --> 00:35:56,500 This migration happens in the entire oceans, 497 00:35:56,500 --> 00:35:58,860 every day, so this is enormous. 498 00:35:58,860 --> 00:36:01,980 This is like the largest migration on Earth. 499 00:36:05,460 --> 00:36:08,900 We know of no greater daily movement 500 00:36:08,900 --> 00:36:12,540 of animal biomass anywhere on the planet. 501 00:36:13,860 --> 00:36:16,060 And as the zooplankton rise, 502 00:36:16,060 --> 00:36:20,260 they cause another huge daily change to the Earth. 503 00:36:20,260 --> 00:36:23,340 They might be small, but Claire has found 504 00:36:23,340 --> 00:36:25,700 they have serious appetites. 505 00:36:28,940 --> 00:36:32,540 Claire's research has shown that some plankton can eat as much 506 00:36:32,540 --> 00:36:36,700 as their own body weight in food in a single day. 507 00:36:36,700 --> 00:36:39,140 And to put that in human terms, 508 00:36:39,140 --> 00:36:42,820 that is the equivalent of me having to eat 509 00:36:42,820 --> 00:36:47,900 this many sandwiches every hour of every day. 510 00:36:48,620 --> 00:36:51,980 Can I at least get a glass of water with this? 511 00:36:54,020 --> 00:36:58,060 This feeding frenzy travels around the world's oceans 512 00:36:58,060 --> 00:37:03,060 as night falls - a Mexican wave of binge eating that never ever stops. 513 00:37:05,780 --> 00:37:09,380 After nine hours, over 3.5 billion tonnes 514 00:37:09,380 --> 00:37:12,740 of zooplankton have completed their daily migration 515 00:37:12,740 --> 00:37:17,740 and they have eaten around 3.4 billion tonnes of phytoplankton. 516 00:37:18,580 --> 00:37:22,860 That's almost eight times the weight of all the people on Earth. 517 00:37:30,900 --> 00:37:34,140 And if life can change so much below the water, 518 00:37:34,140 --> 00:37:36,620 what's going on up above? 519 00:37:38,060 --> 00:37:42,580 Life on land never stands still - not even trees - 520 00:37:42,580 --> 00:37:47,620 and scientists are finding new ways to keep tabs on it 521 00:37:47,820 --> 00:37:50,540 and figure out what it all means to us. 522 00:37:51,700 --> 00:37:54,700 I really love going into forests. 523 00:37:54,700 --> 00:37:59,380 Trees are, in some ways, the basis of life, and they're beautiful. 524 00:38:03,900 --> 00:38:05,700 That one looks good. 525 00:38:05,700 --> 00:38:07,300 Yeah. 526 00:38:07,300 --> 00:38:12,020 Professor Lola Fatoyinbo and David Lagomasino are tackling 527 00:38:12,020 --> 00:38:13,620 a seemingly impossible task. 528 00:38:13,620 --> 00:38:15,620 This one. All right. 529 00:38:15,620 --> 00:38:19,300 Keeping track of all of the trees in the world. 530 00:38:19,300 --> 00:38:21,060 18 metres. 531 00:38:21,060 --> 00:38:22,900 I'll start the scan now. 532 00:38:26,420 --> 00:38:30,660 We scan one tree from one direction. Just like that. 533 00:38:30,660 --> 00:38:34,900 Then, we'll move around a little bit to another spot. Scan two done. 534 00:38:34,900 --> 00:38:38,260 Scan another tree and then we stitch all those images together. 535 00:38:38,260 --> 00:38:39,700 Scan three. 536 00:38:39,700 --> 00:38:43,340 We get a nice 360-degree view of what the forest looks like. 537 00:38:47,180 --> 00:38:49,900 By the time they're done with their lasers 538 00:38:49,900 --> 00:38:51,740 and 360-degree cameras, 539 00:38:51,740 --> 00:38:55,460 they've created a digital copy of the forest accurate enough 540 00:38:55,460 --> 00:39:00,180 to measure every tree and shrub and calculate their growth. 541 00:39:00,180 --> 00:39:01,660 20g per day. 542 00:39:01,660 --> 00:39:03,060 Every single day. 543 00:39:05,820 --> 00:39:10,820 There's a huge range in scales of how fast plants can grow. 544 00:39:12,220 --> 00:39:16,180 There are some bamboos that can grow up to 90 centimetres a day, 545 00:39:16,180 --> 00:39:18,660 where oak trees, on the other hand, will grow 546 00:39:18,660 --> 00:39:21,580 about a millimetre or so a day. 547 00:39:21,580 --> 00:39:24,900 Driving this daily growth is a transformation 548 00:39:24,900 --> 00:39:27,220 that only plants can achieve - 549 00:39:27,220 --> 00:39:29,980 turning sunlight into sugar. 550 00:39:31,780 --> 00:39:35,900 That clever quirk of chemistry called photosynthesis allows plants 551 00:39:35,900 --> 00:39:40,020 to convert that into this. 552 00:39:41,180 --> 00:39:44,420 That simple process of photosynthesis is the only thing 553 00:39:44,420 --> 00:39:46,540 that is keeping us fed down here. 554 00:39:46,540 --> 00:39:50,580 The only reason why we have got energy that we can use. 555 00:39:54,860 --> 00:39:58,100 And if you add all the plants in the world together, 556 00:39:58,100 --> 00:40:01,100 guess how much sugar they make from sunlight? 557 00:40:01,100 --> 00:40:05,740 Daily, photosynthesis produces hundreds of thousands of billions... 558 00:40:05,740 --> 00:40:07,460 SHE LAUGHS 559 00:40:07,460 --> 00:40:09,420 Well, that's a tough one! 560 00:40:09,420 --> 00:40:13,020 Fortunately, David and Lola aren't trying to work it out alone. 561 00:40:13,020 --> 00:40:17,420 They work for Nasa and have access to a fleet of Earth-observing satellites. 562 00:40:17,420 --> 00:40:19,860 So, here, we're starting to see the global picture 563 00:40:19,860 --> 00:40:21,860 of photosynthesis. 564 00:40:21,860 --> 00:40:24,980 Satellites can show us what we can't see, 565 00:40:24,980 --> 00:40:29,500 like photosynthesis in action across the entire world. 566 00:40:29,500 --> 00:40:32,300 Earth-observing satellites are really important, 567 00:40:32,300 --> 00:40:36,420 because we can use them to look at changes in forest cover, 568 00:40:36,420 --> 00:40:39,420 and they give us any idea of what's happening globally 569 00:40:39,420 --> 00:40:40,700 every single day. 570 00:40:44,540 --> 00:40:48,620 A partnership between boots on the ground and eyes in the sky - 571 00:40:48,620 --> 00:40:52,460 that's how scientists like Lola and David are finally able to put 572 00:40:52,460 --> 00:40:56,540 numbers on the colossal changes happening on our green planet - 573 00:40:56,540 --> 00:41:00,900 changes that provide us with food to eat and air to breathe, 574 00:41:00,900 --> 00:41:05,820 from the amount of CO2 plants consume and the oxygen they release, 575 00:41:05,820 --> 00:41:10,380 to the weight of new plant life that every hour brings. 576 00:41:13,180 --> 00:41:17,460 By mid-afternoon, when I'm taking a well-deserved nap after my pile 577 00:41:17,460 --> 00:41:21,340 of sandwiches and cake, scientists with satellites 578 00:41:21,340 --> 00:41:26,340 have worked out that if you took all the new growth in all the forests 579 00:41:27,420 --> 00:41:32,380 and put it in one imaginary plant, you'd get a giant tree 580 00:41:32,700 --> 00:41:36,580 two kilometres high, and in case you're wondering, 581 00:41:36,580 --> 00:41:41,620 the same forests have also made 180 million tonnes of sugar. 582 00:41:43,860 --> 00:41:45,220 Sweet! 583 00:41:46,660 --> 00:41:50,540 But there is a flipside to all of this creation. 584 00:41:50,540 --> 00:41:53,580 Every part of the plant - all the leaves, the branches, 585 00:41:53,580 --> 00:41:57,980 the trunk, the roots - all have this solar energy locked up 586 00:41:57,980 --> 00:42:03,020 inside of them. The problem is, that process is reversible. 587 00:42:03,380 --> 00:42:08,060 All that energy can be released back as heat and light. 588 00:42:12,860 --> 00:42:17,700 This is a film about daily change, and that means destruction, 589 00:42:17,700 --> 00:42:19,180 not just growth. 590 00:42:20,500 --> 00:42:23,660 Because you can't have one thing without the other. 591 00:42:32,340 --> 00:42:36,420 Hello. Hey, mum - I just texted you a picture. 592 00:42:36,420 --> 00:42:40,300 I'm standing right now, right in the middle of the house. 593 00:42:40,300 --> 00:42:43,740 They'd bought this house when it was built new in 1975, 594 00:42:43,740 --> 00:42:47,420 so they've lived here for 42 years. 595 00:42:47,420 --> 00:42:49,060 Um... 596 00:42:49,060 --> 00:42:52,180 The file cabinet is still standing there. 597 00:42:52,180 --> 00:42:56,180 Super nice neighbourhood - it was where I was raised. 598 00:42:57,580 --> 00:43:01,060 But there's going to be very little, if anything. 599 00:43:02,580 --> 00:43:06,020 I'll dig around here, see what I can find, and, er... 600 00:43:09,420 --> 00:43:11,020 All right, love you guys. 601 00:43:24,660 --> 00:43:28,100 In California, they're facing the worst wildfires 602 00:43:28,100 --> 00:43:29,580 in living memory. 603 00:43:32,140 --> 00:43:34,620 Major Baird, this is geo-rectified, right? 604 00:43:34,620 --> 00:43:37,540 Can you show him where the bird is on the map? 605 00:43:37,540 --> 00:43:42,340 This particular fire has grown 14 miles in one day, 606 00:43:42,340 --> 00:43:45,900 which, relative size, is about twice the size of San Francisco County. 607 00:43:45,900 --> 00:43:48,580 It's down all the way into suburban areas, 608 00:43:48,580 --> 00:43:52,140 all the way down into cities and structures. 609 00:43:52,140 --> 00:43:54,460 The fire doesn't care what it burns. 610 00:43:57,060 --> 00:44:00,380 The power went out. My parents are awakened by the neighbour 611 00:44:00,380 --> 00:44:03,020 and the police saying, "You've got to go right now," 612 00:44:03,020 --> 00:44:06,860 and they left my mum's car, because they couldn't get the door 613 00:44:06,860 --> 00:44:11,660 open easily and in a hurry, and you can see what happened with that. 614 00:44:12,780 --> 00:44:17,140 A freak event for LA, but for the Earth as a whole, 615 00:44:17,140 --> 00:44:19,300 this is business as usual. 616 00:44:19,300 --> 00:44:22,020 Right now, as you watch this, somewhere on Earth, 617 00:44:22,020 --> 00:44:23,780 a wildfire is raging. 618 00:44:23,780 --> 00:44:25,740 It's a natural process, 619 00:44:25,740 --> 00:44:29,300 and we've learned the hard way that trying to stop it 620 00:44:29,300 --> 00:44:31,700 only makes matters worse. 621 00:44:31,700 --> 00:44:34,620 About 100 years ago, we adopted a philosophy 622 00:44:34,620 --> 00:44:37,940 where we were going to put every fire out immediately. 623 00:44:37,940 --> 00:44:42,940 That has led to a cumulative effect where the vegetative matter, 624 00:44:44,020 --> 00:44:48,700 the ecosystem has begun to build up, and it's built up for so long 625 00:44:48,700 --> 00:44:51,780 in so many places, these areas are essentially 626 00:44:51,780 --> 00:44:54,100 tinderboxes, ready for a spark. 627 00:44:55,260 --> 00:44:56,900 THUNDER CRASHES 628 00:44:57,940 --> 00:45:01,100 And with 4 million lightning strikes every day, 629 00:45:01,100 --> 00:45:04,620 there are a lot of ways for the energy harnessed from years 630 00:45:04,620 --> 00:45:07,500 and years of sunlight to be let loose. 631 00:45:09,660 --> 00:45:12,860 Fires are an inevitable consequence of growth - 632 00:45:12,860 --> 00:45:15,980 an unstoppable agent of change. 633 00:45:15,980 --> 00:45:19,660 The problem for us is that we've chosen to live 634 00:45:19,660 --> 00:45:22,580 where fires are most likely. 635 00:45:22,580 --> 00:45:25,060 People in California love the Mediterranean climate, 636 00:45:25,060 --> 00:45:27,340 and it's a wonderful place to live. 637 00:45:27,340 --> 00:45:30,140 The problem is that it's had a fire history 638 00:45:30,140 --> 00:45:32,900 that goes back millennia. 639 00:45:32,900 --> 00:45:36,140 We know that fire's going to happen. 640 00:45:36,140 --> 00:45:39,260 It WILL burn here. It's supposed to burn here. 641 00:45:39,260 --> 00:45:41,380 We're just trying to do our best to contain it. 642 00:45:47,140 --> 00:45:50,940 By the time most of us have completed a full day's work, 643 00:45:50,940 --> 00:45:55,940 wildfires have raged through 5,000 square kilometres of forest, 644 00:45:56,260 --> 00:46:01,300 turning to ash an area the size of the Grand Canyon National Park. 645 00:46:10,140 --> 00:46:14,180 Earthquakes, fires, 646 00:46:14,180 --> 00:46:18,260 landslides and floods all seem 647 00:46:18,260 --> 00:46:20,420 like things we could do with a lot less of, 648 00:46:20,420 --> 00:46:23,300 but actually, there is a theory of evolution 649 00:46:23,300 --> 00:46:26,260 that says that with the right amount of change, 650 00:46:26,260 --> 00:46:29,980 you can create the right conditions for new life to come through. 651 00:46:29,980 --> 00:46:32,500 But you don't want too much disruption, 652 00:46:32,500 --> 00:46:35,540 otherwise life won't have a chance to get started at all. 653 00:46:37,660 --> 00:46:40,980 In an environment where nothing much changes, 654 00:46:40,980 --> 00:46:45,820 there's less diversity of species, but throw in a bit of disaster, 655 00:46:45,820 --> 00:46:49,260 and it mixes things up a bit. 656 00:46:49,260 --> 00:46:53,060 And for the planet as a whole, disasters can clear the way 657 00:46:53,060 --> 00:46:56,180 for new species to emerge - 658 00:46:56,180 --> 00:46:59,980 like the way that mammals could flourish after the loss 659 00:46:59,980 --> 00:47:02,140 of the dinosaurs, 660 00:47:02,140 --> 00:47:04,420 which worked out rather well for us. 661 00:47:06,700 --> 00:47:10,900 Over the course of our day, we've seen how Earth's constant 662 00:47:10,900 --> 00:47:15,140 reinvention makes our world go around, but at night, 663 00:47:15,140 --> 00:47:17,380 something else is revealed. 664 00:47:17,380 --> 00:47:21,300 Our planet isn't a self-contained system with the same old ingredients 665 00:47:21,300 --> 00:47:24,500 getting mixed up over and over. 666 00:47:24,500 --> 00:47:28,820 We're part of a much bigger system where cosmic influences 667 00:47:28,820 --> 00:47:31,020 stir things up a bit. 668 00:47:31,020 --> 00:47:33,420 WHIRRING 669 00:47:33,420 --> 00:47:35,380 And at the end of each day, 670 00:47:35,380 --> 00:47:38,540 the Earth isn't quite what it used to be. 671 00:47:41,380 --> 00:47:46,460 It's quite amazing scene to see - the sky just goes on fire. 672 00:47:48,940 --> 00:47:51,220 I can see a handful of stars, so... 673 00:47:51,220 --> 00:47:54,780 It's kind of strange to see so much power and feel that you're part 674 00:47:54,780 --> 00:47:58,900 of something bigger, part of a huge nature, which is quite amazing. 675 00:48:01,060 --> 00:48:05,740 Astronomer Saevar Helgi Bragason and photographer Oli Haukur Myrdal 676 00:48:05,740 --> 00:48:10,780 are hoping to witness a cosmic light show caused by a storm in space. 677 00:48:14,060 --> 00:48:16,700 And if you want to know the space weather forecast, 678 00:48:16,700 --> 00:48:18,500 these are the people to ask. 679 00:48:18,500 --> 00:48:20,740 So it looks like it erupted yesterday morning, 680 00:48:20,740 --> 00:48:21,980 but I'm not sure... 681 00:48:21,980 --> 00:48:25,580 The weather in space may not seem like our problem, but it can cause 682 00:48:25,580 --> 00:48:27,860 chaos for us earthlings. 683 00:48:27,860 --> 00:48:29,820 When activity is particularly strong, 684 00:48:29,820 --> 00:48:31,740 the kinds of impacts would include 685 00:48:31,740 --> 00:48:35,220 equipment failure, equipment damage. It can also include a blackout. 686 00:48:39,060 --> 00:48:42,740 Bad space weather comes from the sun, which sends a constant 687 00:48:42,740 --> 00:48:47,380 stream of charged particles called the solar wind towards the Earth 688 00:48:47,380 --> 00:48:51,460 at up to 3 million kilometres an hour, and sometimes, 689 00:48:51,460 --> 00:48:55,340 there are more violent outbursts that can fry satellites 690 00:48:55,340 --> 00:48:56,940 and knock out power grids. 691 00:48:58,380 --> 00:49:01,660 This is the sun just 15 minutes ago. 692 00:49:01,660 --> 00:49:03,340 But for Saevar and Oli, 693 00:49:03,340 --> 00:49:06,300 a forecast for bad space weather is exactly 694 00:49:06,300 --> 00:49:08,540 what they've been waiting for... 695 00:49:09,860 --> 00:49:13,380 ..so they can witness what happens when the solar wind collides 696 00:49:13,380 --> 00:49:15,260 with our planet. 697 00:49:15,260 --> 00:49:18,500 Now, the solar wind is just a stream of charged particles 698 00:49:18,500 --> 00:49:21,300 and when these particles hit the Earth, they are channelled 699 00:49:21,300 --> 00:49:23,780 by the magnetic field towards the poles, 700 00:49:23,780 --> 00:49:26,180 where they excite the atmosphere. 701 00:49:32,220 --> 00:49:35,860 It's time to get the drone airborne... 702 00:49:37,140 --> 00:49:41,220 ..ready for when the solar wind hits our atmosphere to create... 703 00:49:42,340 --> 00:49:44,540 ..the aurora borealis... 704 00:49:46,300 --> 00:49:48,140 ..or northern lights. 705 00:50:00,380 --> 00:50:02,580 It's amazing. It looks good. It looks really good. 706 00:50:07,260 --> 00:50:10,420 But there's a price to pay for this spectacle. 707 00:50:10,420 --> 00:50:13,620 The latest science is revealing how the lights are actually 708 00:50:13,620 --> 00:50:17,980 a symptom of a huge daily change to Earth. 709 00:50:17,980 --> 00:50:22,220 I hate to break it to you, but our atmosphere is leaking. 710 00:50:22,220 --> 00:50:24,860 When we have the particles that flow from the sun, 711 00:50:24,860 --> 00:50:29,300 they not only excite the atoms in the atmosphere of the Earth, 712 00:50:29,300 --> 00:50:31,780 but they're also causing some of the particles to stream 713 00:50:31,780 --> 00:50:33,780 out into space, like helium. 714 00:50:33,780 --> 00:50:36,260 So when you're looking at, or rather through, an aurora, 715 00:50:36,260 --> 00:50:40,220 you're actually looking at helium ions being lost to space. 716 00:50:40,220 --> 00:50:44,180 In 2010, people were worried that our supply of helium 717 00:50:44,180 --> 00:50:45,220 was running out. 718 00:50:45,220 --> 00:50:48,460 There were even some concerned newspaper reports that a single 719 00:50:48,460 --> 00:50:53,500 party balloon would end up costing as much as £80, 720 00:50:53,500 --> 00:50:58,540 all because our helium was just floating off into space. 721 00:50:58,780 --> 00:51:01,580 And once it's gone, it's gone. 722 00:51:01,580 --> 00:51:05,020 But thankfully, in 2016, 723 00:51:05,020 --> 00:51:07,940 a new deposit of helium was discovered, meaning 724 00:51:07,940 --> 00:51:11,340 that for a while yet, the party can continue. 725 00:51:14,540 --> 00:51:19,180 Since you woke up this morning, about 80 tonnes of atmosphere 726 00:51:19,180 --> 00:51:21,340 have been lost into space... 727 00:51:23,580 --> 00:51:25,660 ..including enough helium to fill 728 00:51:25,660 --> 00:51:29,260 800,000 reasonably priced party balloons. 729 00:51:37,420 --> 00:51:42,460 A kilogram every second - that's a pretty drastic weight loss, 730 00:51:42,900 --> 00:51:46,580 but you'll be pleased to know the planet is offsetting some of that. 731 00:51:46,580 --> 00:51:48,740 As we hurtle through the cosmos, 732 00:51:48,740 --> 00:51:53,420 we put a bit of weight back on by picking up a few fellow travellers. 733 00:52:03,620 --> 00:52:05,540 It looks pretty clear out here right now. 734 00:52:05,540 --> 00:52:07,860 Do you think that'll hold for tonight? Sure hope so. 735 00:52:07,860 --> 00:52:11,020 We're looking for a wonderful night under the stars. 736 00:52:11,020 --> 00:52:14,380 Dave Powell is waiting on a special delivery, 737 00:52:14,380 --> 00:52:16,900 shipped express from outer space. 738 00:52:19,340 --> 00:52:24,340 Tonight is the night of the Geminid meteor shower and there's no better 739 00:52:25,020 --> 00:52:29,020 way to see it than in the clear night skies of the desert 740 00:52:29,020 --> 00:52:31,380 with some like-minded friends. 741 00:52:31,380 --> 00:52:33,260 Apparently, they're happening all the time, 742 00:52:33,260 --> 00:52:36,220 but you can only really see them at night. 743 00:52:36,220 --> 00:52:38,620 THEY EXCLAIM 744 00:52:38,620 --> 00:52:39,980 Where was it, Dave? 745 00:52:39,980 --> 00:52:41,700 LAUGHTER 746 00:52:46,620 --> 00:52:48,420 A lot of people think they're really big, 747 00:52:48,420 --> 00:52:51,660 but they're actually only about the size of a common blueberry. 748 00:52:51,660 --> 00:52:52,820 Ooh! Ooh! 749 00:52:52,820 --> 00:52:55,820 Blueberries are the size of meteors. 750 00:52:55,820 --> 00:52:58,260 THEY EXCLAIM Wow! That was a really good one. 751 00:52:58,260 --> 00:53:00,460 Every time I look at blueberries, I'm going to think that now 752 00:53:00,460 --> 00:53:02,820 for the rest of my life. 753 00:53:02,820 --> 00:53:05,740 There are a lot of blueberries out there. 754 00:53:07,180 --> 00:53:10,580 This is what's happening during the meteor shower. 755 00:53:10,580 --> 00:53:15,620 The Earth is moving through space at over 100,000 kilometres per hour 756 00:53:16,140 --> 00:53:18,740 on a collision course with this dust. 757 00:53:24,060 --> 00:53:26,340 The best way I could describe the meteor shower 758 00:53:26,340 --> 00:53:29,740 would be that the sky is raining diamonds. 759 00:53:29,740 --> 00:53:30,940 Whoa! 760 00:53:31,940 --> 00:53:33,780 It's just magical. 761 00:53:36,020 --> 00:53:40,220 A good meteor shower is, like, 60 an hour. 762 00:53:40,220 --> 00:53:44,140 Here, we are over 100 an hour average. 763 00:53:44,140 --> 00:53:45,180 Oh-oh! 764 00:53:46,780 --> 00:53:49,140 I couldn't even count how many we saw tonight. 765 00:53:49,140 --> 00:53:50,540 Whoa! 766 00:53:50,540 --> 00:53:53,900 Every time you switched a direction, you'd see another one. 767 00:53:53,900 --> 00:53:55,780 You'd look left, look right. 768 00:53:55,780 --> 00:53:59,580 There were points where we saw eight, ten in a single minute. 769 00:53:59,580 --> 00:54:02,260 All the blueberries coming on down. 770 00:54:03,780 --> 00:54:05,340 Oh, nice bright one! 771 00:54:06,500 --> 00:54:09,540 They're tiny, but a lot of them come down. 772 00:54:10,900 --> 00:54:13,780 These meteors burn up in the upper atmosphere, 773 00:54:13,780 --> 00:54:17,540 finally falling to our planet as space dust. 774 00:54:17,540 --> 00:54:20,980 There's so much of it, it adds up, making the Earth 775 00:54:20,980 --> 00:54:23,140 a little bit heavier each day. 776 00:54:24,340 --> 00:54:25,980 Whoa! 777 00:54:29,220 --> 00:54:33,580 And if you added up all the space dust and all the meteorites 778 00:54:33,580 --> 00:54:36,460 that hit our Earth, by the end of the day, 779 00:54:36,460 --> 00:54:41,420 you'd have a single meteorite 55 tonnes in weight. 780 00:54:55,060 --> 00:54:59,620 And there's one last change that's probably the biggest change 781 00:54:59,620 --> 00:55:02,620 of all, and you definitely won't have noticed this one. 782 00:55:04,820 --> 00:55:09,860 As we all know, it takes the Earth one year to go around the sun 783 00:55:10,860 --> 00:55:15,140 and return to what we think is our original location, 784 00:55:15,140 --> 00:55:16,780 but that's not quite right. 785 00:55:16,780 --> 00:55:20,780 We're also part of the galaxy, which is spiralling through space 786 00:55:20,780 --> 00:55:25,060 at over 2 million kilometres an hour. 787 00:55:25,060 --> 00:55:29,620 The actual galaxy itself is also in motion. 788 00:55:30,740 --> 00:55:33,700 That means in the course of one day, we have moved 789 00:55:33,700 --> 00:55:38,020 over 50 million kilometres from the day before, 790 00:55:38,020 --> 00:55:42,980 so all of us are never going to return to where we were yesterday. 791 00:55:42,980 --> 00:55:46,820 It makes you realise there's something a lot bigger 792 00:55:46,820 --> 00:55:49,860 than your day-to-day life going on here. 793 00:55:52,540 --> 00:55:56,660 We're all in this together, moving forward through space. 794 00:55:59,860 --> 00:56:04,100 By the time you watch this, we're already somewhere else 795 00:56:04,100 --> 00:56:06,700 and also somewhere else now. 796 00:56:12,980 --> 00:56:16,300 Since we woke up this morning, so much has happened, 797 00:56:16,300 --> 00:56:19,540 but things won't stop just because we head off to bed. 798 00:56:19,540 --> 00:56:21,740 While you're sleeping tonight, 799 00:56:21,740 --> 00:56:25,220 spare a thought for what the planet will be doing. 800 00:56:26,940 --> 00:56:28,860 New land will be created 801 00:56:28,860 --> 00:56:32,700 and tugged into day-altering tides by the moon. 802 00:56:35,300 --> 00:56:40,020 Lakebeds will take flight and fertilise distant continents, 803 00:56:40,020 --> 00:56:44,980 as mountains are broken down into nutrients for the most 804 00:56:45,100 --> 00:56:47,780 abundant form of life on Earth. 805 00:56:49,780 --> 00:56:52,500 Trees will capture enough sunlight 806 00:56:52,500 --> 00:56:55,780 to keep the entire planet fed with sunbeams, 807 00:56:55,780 --> 00:56:59,940 and wildfires will burn acres of forests to allow 808 00:56:59,940 --> 00:57:01,740 new life a chance. 809 00:57:03,420 --> 00:57:06,340 And all the while, we're leaking atmosphere 810 00:57:06,340 --> 00:57:08,820 and careering through the cosmos. 811 00:57:10,180 --> 00:57:11,860 Whoa! 812 00:57:11,860 --> 00:57:14,020 As we recharge our batteries, 813 00:57:14,020 --> 00:57:17,940 the Earth will still be keeping life ticking, 814 00:57:17,940 --> 00:57:22,780 changing enough to keep us alive, but not so much we can't survive. 815 00:57:22,780 --> 00:57:27,340 So, be glad that it's a new world tomorrow, because if it wasn't, 816 00:57:27,340 --> 00:57:29,140 you wouldn't be on it.