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Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:03,190 --> 00:00:06,726 Did you ever stop to wonder where your car came from? 2 00:00:06,727 --> 00:00:10,131 I mean, really came from? 3 00:00:10,131 --> 00:00:14,567 Every component has a mind-blowing backstory, 4 00:00:14,567 --> 00:00:17,606 an epic journey through time and space 5 00:00:17,606 --> 00:00:21,274 filled with the most violent events since the big bang. 6 00:00:23,144 --> 00:00:28,917 The history of your car is the history of the universe. 7 00:00:48,973 --> 00:00:51,343 How old is your car? 8 00:00:51,344 --> 00:00:54,179 My car is about 5 years old. 9 00:00:54,179 --> 00:00:56,848 My car was assembled in 2001. 10 00:00:56,850 --> 00:01:00,688 The car I drive is pretty old. It was manufactured in 1991. 11 00:01:00,689 --> 00:01:03,256 But that's just when the pieces and parts were assembled. 12 00:01:05,992 --> 00:01:08,829 To find out how old a car really is, 13 00:01:08,829 --> 00:01:13,534 we need to take a trip back to the beginning of time. 14 00:01:13,534 --> 00:01:17,772 Your car began its life billions of years ago, 15 00:01:17,774 --> 00:01:20,808 billions of miles away in deep space. 16 00:01:22,343 --> 00:01:24,980 The things that make up cars, those atoms, most of them 17 00:01:24,980 --> 00:01:27,817 were forged well before our Earth was born. 18 00:01:29,787 --> 00:01:32,822 You think your car is a clunker? 19 00:01:32,823 --> 00:01:37,061 It's actually 13.8 billion years old. 20 00:01:39,264 --> 00:01:40,765 All right. Let's do it, sir. 21 00:01:44,002 --> 00:01:47,003 So, what's the stuff that cars are made of? 22 00:01:47,004 --> 00:01:49,843 Best way to find out... Tear one apart. 23 00:01:54,014 --> 00:01:58,252 Iron, plastics, oils and rubber are the first to go... 24 00:02:00,822 --> 00:02:02,290 In another half hour or so, 25 00:02:02,290 --> 00:02:04,058 this baby's gonna be completely stripped. 26 00:02:05,492 --> 00:02:07,661 I can't wait to see it. 27 00:02:09,097 --> 00:02:12,966 Then aluminum, silicon, copper. 28 00:02:12,967 --> 00:02:15,135 And finally, precious metals, 29 00:02:15,137 --> 00:02:17,105 like platinum and gold. 30 00:02:20,210 --> 00:02:24,615 Each of these materials is crucial for building a car. 31 00:02:27,751 --> 00:02:32,489 But in the earliest days of the universe, none of them existed. 32 00:02:41,299 --> 00:02:43,901 13.8 billion years ago, 33 00:02:43,902 --> 00:02:48,740 time and space are created in the big bang. 34 00:02:48,740 --> 00:02:53,478 The early universe is filled with nothing but energy. 35 00:02:53,478 --> 00:02:57,983 After the big bang, it was just a chaotic glob of stuff, 36 00:02:57,984 --> 00:03:00,419 nothing like what you see today. 37 00:03:00,419 --> 00:03:02,788 As the early universe cools, 38 00:03:02,789 --> 00:03:06,927 the energy gives way to unstable matter and antimatter, 39 00:03:06,929 --> 00:03:12,032 then protons and neutrons and, finally, atoms. 40 00:03:12,032 --> 00:03:16,771 But none of them are iron, silicon or carbon. 41 00:03:16,772 --> 00:03:20,742 The vast, gassy clouds are mostly hydrogen. 42 00:03:22,343 --> 00:03:25,248 Something had to happen to give us everything else. 43 00:03:25,250 --> 00:03:27,985 And everything was actually made 44 00:03:27,985 --> 00:03:29,653 from hydrogen building blocks. 45 00:03:32,223 --> 00:03:35,191 An atom of hydrogen is the simplest and lightest 46 00:03:35,192 --> 00:03:36,993 atom in the universe, 47 00:03:36,995 --> 00:03:40,131 just a single positively charged proton 48 00:03:40,132 --> 00:03:42,802 bound to a single electron. 49 00:03:44,403 --> 00:03:47,538 The universe then builds up bigger atoms like carbon 50 00:03:47,538 --> 00:03:51,110 and iron by fusing hydrogen atoms together. 51 00:03:52,513 --> 00:03:54,979 Everything starts from simpler origins. 52 00:03:54,980 --> 00:03:57,317 An iron atom is actually lots and lots 53 00:03:57,317 --> 00:04:00,754 of simple hydrogen atoms that were stuck together. 54 00:04:00,756 --> 00:04:05,056 At first, this versatile proton building block 55 00:04:05,057 --> 00:04:06,727 doesn't want to stick. 56 00:04:06,728 --> 00:04:09,195 Protons are positively charged. 57 00:04:09,197 --> 00:04:11,932 So as you push them closer together, they're gonna resist 58 00:04:11,933 --> 00:04:13,335 coming closer together. 59 00:04:13,336 --> 00:04:15,671 They really don't want to hang out. 60 00:04:15,673 --> 00:04:18,507 This repulsion makes the early universe 61 00:04:18,509 --> 00:04:23,312 a maelstrom of hydrogen atoms swerving to avoid each other. 62 00:04:23,312 --> 00:04:26,348 But if you can get them to a point where you can 63 00:04:26,350 --> 00:04:28,218 shove them together enough, at some point, 64 00:04:28,220 --> 00:04:29,987 they're gonna lock together. 65 00:04:38,497 --> 00:04:41,365 Pushing atoms together so strongly they stick 66 00:04:41,367 --> 00:04:43,202 is called nuclear fusion. 67 00:04:45,338 --> 00:04:48,341 It's the first step for turning a universe full of gas 68 00:04:48,341 --> 00:04:51,810 into one filled with the ingredients for planets, 69 00:04:51,812 --> 00:04:55,048 people, and cars. 70 00:04:55,050 --> 00:04:58,483 So, how do you get two atoms to fuse? 71 00:04:58,485 --> 00:05:02,524 This guy's been doing it in his garage since he was 14. 72 00:05:04,560 --> 00:05:09,165 Taylor Wilson is obsessed with nuclear fusion. 73 00:05:11,468 --> 00:05:13,500 Yeah, the neighbors know about the radioactive stuff 74 00:05:13,500 --> 00:05:14,903 that's in the garage. 75 00:05:14,904 --> 00:05:16,839 And so does the government. 76 00:05:16,841 --> 00:05:19,007 It's all relatively low level. 77 00:05:20,411 --> 00:05:21,810 That's my watch going off. 78 00:05:21,812 --> 00:05:23,512 I think I'm the only person I've ever met 79 00:05:23,514 --> 00:05:25,449 with a geiger-counter watch. 80 00:05:28,452 --> 00:05:31,355 The centerpiece of Taylor's nuclear man cave 81 00:05:31,355 --> 00:05:35,226 is this precision-engineered fusion reactor, 82 00:05:35,228 --> 00:05:37,827 which he built when he was still in high school. 83 00:05:37,829 --> 00:05:39,930 Okay, I'll let in some gas now. 84 00:05:39,932 --> 00:05:43,134 The first ingredient... Hydrogen gas. 85 00:05:43,134 --> 00:05:45,805 And it will be flowed into the chamber through this very 86 00:05:45,805 --> 00:05:48,673 precise sapphire leak valve. 87 00:05:48,673 --> 00:05:52,877 The next ingredient... High-voltage electricity. 88 00:05:54,915 --> 00:05:56,682 Hmm. 89 00:05:56,683 --> 00:05:58,985 Oh, I wonder what the problem is. 90 00:05:58,987 --> 00:06:00,956 - Power su... - You probably want to plug it in. 91 00:06:00,956 --> 00:06:03,255 Power supply is not plugged in. Okay, let's try that again. 92 00:06:03,257 --> 00:06:04,860 That's embarrassing. 93 00:06:06,161 --> 00:06:08,831 I'm getting power from the laundry room now. 94 00:06:14,470 --> 00:06:18,740 Taylor passes a high voltage through a small, spherical cage 95 00:06:18,742 --> 00:06:21,310 that sits inside the reactor. 96 00:06:21,312 --> 00:06:23,146 The negatively charged cage 97 00:06:23,148 --> 00:06:26,350 quickly draws the hydrogen ions inside it. 98 00:06:26,350 --> 00:06:28,086 So it's taking all those ions 99 00:06:28,086 --> 00:06:29,586 and sucking them towards the center. 100 00:06:29,586 --> 00:06:32,624 And as they fly in they get confined, 101 00:06:32,625 --> 00:06:35,495 and hopefully they collide with each other and fuse. 102 00:06:35,495 --> 00:06:39,630 The temperature of the atoms inside the cage is now so great 103 00:06:39,632 --> 00:06:42,500 that hydrogen atoms are fusing together, 104 00:06:42,500 --> 00:06:46,172 creating heavier helium atoms and a burst of energy 105 00:06:46,173 --> 00:06:48,807 hotter than the surface of the sun. 106 00:06:48,807 --> 00:06:53,146 It's that little, tiny blob of plasma inside those grid wires 107 00:06:53,148 --> 00:06:55,582 that's kind of like a star in a jar. 108 00:07:02,790 --> 00:07:04,858 13 billion years ago, 109 00:07:04,860 --> 00:07:07,761 the universe uses gravity to fuse atoms 110 00:07:07,762 --> 00:07:09,999 instead of an electrical cage. 111 00:07:14,168 --> 00:07:17,774 Across the cosmos, vast clouds of hydrogen gas 112 00:07:17,776 --> 00:07:20,312 collapse under their own gravity. 113 00:07:21,646 --> 00:07:24,079 Pressure and temperature build 114 00:07:24,081 --> 00:07:26,951 as more and more gas gets sucked in. 115 00:07:26,951 --> 00:07:30,021 Eventually, fusion sparks deep in the core 116 00:07:30,021 --> 00:07:32,290 of these giant balls of gas, 117 00:07:32,290 --> 00:07:35,158 and the first stars start to manufacture 118 00:07:35,159 --> 00:07:38,999 many of the heavy elements that make up your car today. 119 00:07:40,701 --> 00:07:44,071 A star is basically a machine for turning lighter elements 120 00:07:44,072 --> 00:07:45,505 into heavier elements. 121 00:07:47,740 --> 00:07:50,442 Fusion takes place only inside the core 122 00:07:50,442 --> 00:07:52,278 of these first stars, 123 00:07:52,279 --> 00:07:56,216 fusing hydrogen atoms together to create helium. 124 00:07:56,216 --> 00:07:59,120 And when all the hydrogen in the core is used up, 125 00:07:59,120 --> 00:08:02,389 the star finds new fuel to burn. 126 00:08:02,391 --> 00:08:06,360 After you burn hydrogen to form helium, the core of the star 127 00:08:06,362 --> 00:08:08,596 begins to collapse and get hotter. 128 00:08:08,598 --> 00:08:12,103 And there is enough energy then to fuse three helium nuclei 129 00:08:12,103 --> 00:08:13,970 into carbon. 130 00:08:15,372 --> 00:08:18,408 And then that fuses to form nitrogen, oxygen, 131 00:08:18,410 --> 00:08:21,478 silicon, iron. 132 00:08:21,480 --> 00:08:24,882 But this incredible production line of elements 133 00:08:24,884 --> 00:08:27,050 can't go on forever. 134 00:08:27,050 --> 00:08:29,019 The heavier atoms you ram together, 135 00:08:29,019 --> 00:08:30,855 the less energy you get out. 136 00:08:30,855 --> 00:08:32,789 So you turn hydrogen into helium. 137 00:08:32,790 --> 00:08:35,360 Helium becomes carbon, nitrogen, oxygen. 138 00:08:35,360 --> 00:08:39,063 But every time there's a bit less energy to be had 139 00:08:39,065 --> 00:08:41,399 until you get to iron. 140 00:08:41,400 --> 00:08:45,804 The iron that is in your car is actually essentially 141 00:08:45,806 --> 00:08:49,542 a deadly poison when it comes to a star. 142 00:08:49,543 --> 00:08:54,115 It's robbing that star of the heat needed to keep itself up. 143 00:08:58,519 --> 00:09:01,557 So the star collapses, dies, and explodes 144 00:09:01,557 --> 00:09:04,592 at the moment you create iron in the core. 145 00:09:04,594 --> 00:09:06,695 I mean, literally the fraction of a second. 146 00:09:06,696 --> 00:09:08,195 I'm not kidding. 147 00:09:08,196 --> 00:09:12,235 That's how dramatic and weird the steel in your car is. 148 00:09:15,371 --> 00:09:18,308 The explosion, called a supernova, 149 00:09:18,309 --> 00:09:22,812 is one of the brightest and most violent events in the universe. 150 00:09:22,812 --> 00:09:27,150 It releases enough energy to dwarf what the sun puts out 151 00:09:27,152 --> 00:09:28,951 over its entire lifetime. 152 00:09:28,952 --> 00:09:32,190 And all of the elements that it has created are then dispersed 153 00:09:32,191 --> 00:09:34,024 out into space. 154 00:09:34,024 --> 00:09:36,827 The gassy remains of the explosion are called 155 00:09:36,828 --> 00:09:39,163 a supernova remnant, 156 00:09:39,164 --> 00:09:41,567 an expanding bubble of hydrogen gas 157 00:09:41,567 --> 00:09:45,437 from the outer layers of the star that mixes with stardust, 158 00:09:45,438 --> 00:09:51,443 the carbon, oxygen, silicon and iron from its core. 159 00:09:51,445 --> 00:09:55,347 And this same 13-billion-year-old stardust 160 00:09:55,349 --> 00:09:58,286 helped you drive to work last week. 161 00:09:58,287 --> 00:10:01,657 This was once in the core of a dying star. 162 00:10:01,658 --> 00:10:02,957 And who knows? 163 00:10:02,958 --> 00:10:05,227 Maybe some of the iron atoms in this brake disc 164 00:10:05,229 --> 00:10:08,263 were forged in the heart of the very first generation of stars 165 00:10:08,264 --> 00:10:10,767 that illuminated the universe. 166 00:10:10,768 --> 00:10:14,004 When you're pumpin' iron, you're pumpin' a universe. 167 00:10:20,044 --> 00:10:23,447 The first generation of stars created the materials in a car's 168 00:10:23,447 --> 00:10:27,019 chassis, body, windshield and seats. 169 00:10:27,019 --> 00:10:30,120 But we're still missing key components, like the copper 170 00:10:30,121 --> 00:10:32,591 for the car's electronics. 171 00:10:32,591 --> 00:10:36,227 To create this crucial metal, a new generation of stars 172 00:10:36,229 --> 00:10:39,700 must die an even stranger death. 173 00:10:50,865 --> 00:10:54,668 Picture our universe as the very first stars 174 00:10:54,669 --> 00:10:56,972 come to the end of their lives. 175 00:10:57,572 --> 00:11:02,243 The early milky way is filled with flashes 176 00:11:02,244 --> 00:11:05,048 as star after star explodes. 177 00:11:06,881 --> 00:11:10,285 These violent supernovas hurl a rich cocktail 178 00:11:10,287 --> 00:11:13,056 of heavy elements into space, 179 00:11:13,057 --> 00:11:17,460 the carbon, silicon, aluminum and iron atoms 180 00:11:17,461 --> 00:11:21,067 that will one day build our cars here on Earth. 181 00:11:30,009 --> 00:11:32,076 But take a closer look at today's cars, 182 00:11:32,077 --> 00:11:34,678 and there are many more elements heavier than iron, 183 00:11:34,679 --> 00:11:37,850 like copper in the wiring 184 00:11:37,851 --> 00:11:41,620 and gold in the connectors. 185 00:11:41,621 --> 00:11:44,825 How did the universe create these heavy metals? 186 00:11:44,826 --> 00:11:50,063 In the case of copper, the answer is reincarnation. 187 00:11:50,065 --> 00:11:54,235 Copper is one metal that your car can't live without. 188 00:11:54,235 --> 00:11:57,538 Turns out there's over a mile of copper in the average car. 189 00:11:57,538 --> 00:12:01,475 And the reason why is because copper is an excellent 190 00:12:01,476 --> 00:12:03,080 electrical conductor. 191 00:12:05,950 --> 00:12:10,086 Copper's also used to conduct heat in radiators. 192 00:12:12,456 --> 00:12:15,860 It stops bearings from failing when you need to go fast. 193 00:12:15,860 --> 00:12:18,831 And when you need to stop, copper provides the friction 194 00:12:18,831 --> 00:12:21,765 in your brake pads. 195 00:12:21,767 --> 00:12:25,202 But the story of how that copper came to exist 196 00:12:25,203 --> 00:12:28,241 and be on Earth, that's a truly remarkable story. 197 00:12:31,979 --> 00:12:36,384 Copper begins with the death of a first-generation star. 198 00:12:38,653 --> 00:12:42,422 The expanding supernova remnant slams into neighboring clouds 199 00:12:42,423 --> 00:12:47,763 of gas, creating a shock wave of pressure, 200 00:12:47,764 --> 00:12:51,365 giving birth to a new generation of stars. 201 00:12:56,740 --> 00:12:59,142 There are cycles to the universe. 202 00:12:59,143 --> 00:13:01,409 Stars form. They live out their lives. 203 00:13:01,410 --> 00:13:03,212 They die. They blow off winds 204 00:13:03,214 --> 00:13:06,615 and they explode, ceding their material into gas clouds 205 00:13:06,616 --> 00:13:10,320 which then form new stars with heavier elements in them, 206 00:13:10,321 --> 00:13:13,624 which will repeat the cycle again. 207 00:13:13,625 --> 00:13:15,859 So if you want to think about it that way, 208 00:13:15,860 --> 00:13:18,063 the universe is the ultimate recycler. 209 00:13:20,932 --> 00:13:22,801 The hydrogen gas that forms these 210 00:13:22,802 --> 00:13:26,171 second-generation stars is peppered with the carbon, 211 00:13:26,172 --> 00:13:30,278 aluminum and iron thrown out by the supernova remnant. 212 00:13:31,977 --> 00:13:35,347 The biggest of these dirty stars burn brightly 213 00:13:35,349 --> 00:13:37,049 for a few million years. 214 00:13:37,051 --> 00:13:40,955 Then they undergo an incredible metamorphosis. 215 00:13:46,094 --> 00:13:50,698 The star grows suddenly to 100 times its previous size. 216 00:13:52,769 --> 00:13:58,273 Then it cools and turns a ghostly red. 217 00:13:58,274 --> 00:14:01,410 The second-generation star has transformed 218 00:14:01,412 --> 00:14:03,879 into a red supergiant. 219 00:14:03,879 --> 00:14:08,518 And it's in these diffuse outer layers that iron-rich stardust 220 00:14:08,519 --> 00:14:11,956 is slowly converted into copper... 221 00:14:11,956 --> 00:14:14,259 But not by fusion. 222 00:14:14,259 --> 00:14:17,293 That iron nucleus has 26 protons. 223 00:14:17,294 --> 00:14:19,764 That's a serious electric charge. 224 00:14:19,765 --> 00:14:23,001 So it's gonna repel any protons we try to shoot in there. 225 00:14:25,104 --> 00:14:28,274 How do we get more protons in? 226 00:14:28,274 --> 00:14:32,447 The way we get those protons in there is we trick the nucleus. 227 00:14:32,447 --> 00:14:35,783 Instead of shooting in protons, we shoot in neutrons. 228 00:14:39,253 --> 00:14:42,756 Colliding atoms in the outer layers of a star 229 00:14:42,758 --> 00:14:45,960 sometimes spit out neutrons. 230 00:14:45,961 --> 00:14:49,397 Neutrons don't have a charge, so they're not repelled 231 00:14:49,398 --> 00:14:54,004 by the positively charged protons in the iron stardust. 232 00:14:54,004 --> 00:14:58,509 So these neutrons can stick to the other atoms around them. 233 00:15:00,809 --> 00:15:04,148 An atom is a very tiny thing. It makes a very small target. 234 00:15:04,149 --> 00:15:07,152 But there's a lot of particles flying around near a star. 235 00:15:07,153 --> 00:15:12,155 And if, by chance, a neutron can hit an atom, it can stick. 236 00:15:12,157 --> 00:15:14,993 And that will actually make the nucleus of the atom larger. 237 00:15:16,461 --> 00:15:19,130 Neutron by neutron can hit an atom. 238 00:15:19,131 --> 00:15:23,469 And then that neutron can actually decay into a proton. 239 00:15:23,470 --> 00:15:26,304 The neutron spits out an electron, 240 00:15:26,306 --> 00:15:31,411 and what's left is a proton and a new, bigger atom. 241 00:15:31,412 --> 00:15:33,713 In this case, copper. 242 00:15:33,715 --> 00:15:38,418 Scientists call this magical transformation beta decay. 243 00:15:38,419 --> 00:15:41,788 So you can build up heavy elements very slowly 244 00:15:41,789 --> 00:15:44,459 over the course of thousands or millions of years 245 00:15:44,460 --> 00:15:45,927 just by capturing neutrons. 246 00:15:49,701 --> 00:15:52,772 Eventually, the core of the red supergiant 247 00:15:52,773 --> 00:15:56,706 runs out of fuel, and the star explodes, 248 00:15:56,707 --> 00:16:00,745 blasting its copper-rich outer layer into space. 249 00:16:04,884 --> 00:16:08,486 Thanks to the life and death of two generations of stars, 250 00:16:08,488 --> 00:16:11,359 we can now equip our car with copper wiring. 251 00:16:15,495 --> 00:16:19,100 But we're still short of some even heavier metals, 252 00:16:19,100 --> 00:16:20,801 such as lead for the battery 253 00:16:20,802 --> 00:16:23,437 and gold for the electrical connectors. 254 00:16:26,173 --> 00:16:30,278 To make these truly massive atoms, the universe must create 255 00:16:30,278 --> 00:16:34,850 the most spectacular explosions since the big bang. 256 00:16:47,408 --> 00:16:52,144 To make a car, you need some seriously heavy metal. 257 00:16:52,144 --> 00:16:56,783 Take iridium, a super-tough atom with 77 protons 258 00:16:56,783 --> 00:17:00,154 that's used to coat the tips of spark plugs. 259 00:17:03,993 --> 00:17:09,999 Next on the heavyweight lineup comes gold with 79 protons. 260 00:17:10,000 --> 00:17:13,604 This shiny conductor resists corrosion, making it ideal 261 00:17:13,605 --> 00:17:17,005 for exposed electrical connections. 262 00:17:17,006 --> 00:17:21,078 These connectors here for this airbag assembly are gold. 263 00:17:21,079 --> 00:17:23,480 And so this thing can react really quickly 264 00:17:23,481 --> 00:17:25,317 if there is an accident and save your life. 265 00:17:29,320 --> 00:17:34,326 The biggest atom in a car is lead with 82 protons. 266 00:17:36,930 --> 00:17:40,799 Only lead has the durability to deliver the short burst 267 00:17:40,800 --> 00:17:45,271 of high power needed to start an engine over and over again. 268 00:17:52,146 --> 00:17:55,583 But until very recently, how the universe made these 269 00:17:55,584 --> 00:17:59,153 oversized atoms was a complete mystery. 270 00:17:59,153 --> 00:18:01,924 You can't make gold atoms in a normal star. 271 00:18:03,527 --> 00:18:06,895 You can't make gold atoms in a massive star that's dying. 272 00:18:08,565 --> 00:18:11,667 In order to make atoms this big with this many neutrons, 273 00:18:11,669 --> 00:18:14,372 you need a truly cataclysmic event. 274 00:18:18,710 --> 00:18:21,510 Just a few years ago, most scientists believed 275 00:18:21,511 --> 00:18:25,817 that supernovas were cataclysmic enough to do the job. 276 00:18:28,421 --> 00:18:32,124 But astronomer Edo Berger was not so sure. 277 00:18:32,125 --> 00:18:35,594 If you open any one of these books and flip to the page 278 00:18:35,595 --> 00:18:37,930 that tells you where gold came from, it will tell you 279 00:18:37,931 --> 00:18:42,201 that gold came from supernova explosions. 280 00:18:42,202 --> 00:18:44,336 But nobody had directly observed supernovas 281 00:18:44,337 --> 00:18:46,439 producing elements like gold. 282 00:18:46,440 --> 00:18:49,576 And inside computer simulations, virtual supernovas 283 00:18:49,577 --> 00:18:53,714 lacked the energy to forge these oversized atoms. 284 00:18:53,715 --> 00:18:56,083 Clearly, something was wrong. 285 00:18:56,084 --> 00:18:59,319 But if supernovas weren't powerful enough, 286 00:18:59,320 --> 00:19:01,589 what in the universe was? 287 00:19:01,590 --> 00:19:04,292 To form heavy elements requires a lot of neutrons. 288 00:19:04,294 --> 00:19:07,930 And so another possible theory was that the heaviest elements 289 00:19:07,931 --> 00:19:10,534 were produced in the mergers of two neutron stars 290 00:19:10,535 --> 00:19:12,503 in a binary system. 291 00:19:15,506 --> 00:19:18,275 Neutron stars are some of the weirdest objects 292 00:19:18,276 --> 00:19:20,176 in the universe. 293 00:19:20,178 --> 00:19:23,580 They're formed from the collapsed cores of big stars 294 00:19:23,582 --> 00:19:25,516 when they die. 295 00:19:25,517 --> 00:19:28,053 You're taking a couple of times the mass of the sun 296 00:19:28,054 --> 00:19:30,255 and squeezing it down into a ball 297 00:19:30,256 --> 00:19:32,257 that's only a few miles across. 298 00:19:32,258 --> 00:19:34,660 The electrons and the protons that are flitting around 299 00:19:34,661 --> 00:19:37,497 inside of that combine to form neutrons. 300 00:19:37,498 --> 00:19:41,401 And what you're left with is an extremely dense ball 301 00:19:41,402 --> 00:19:45,173 of neutrons about the size of a city. 302 00:19:46,641 --> 00:19:49,643 Neutron stars are extremely dense. 303 00:19:49,644 --> 00:19:53,247 If you take just a teaspoon of the neutron star material, 304 00:19:53,248 --> 00:19:55,450 it's actually a billion tons. 305 00:19:55,451 --> 00:19:58,420 If neighboring stars die together, 306 00:19:58,421 --> 00:20:01,923 it's possible for the two neutron stars they leave behind 307 00:20:01,924 --> 00:20:05,626 to form a spinning binary pair. 308 00:20:05,627 --> 00:20:08,329 But the partnership is doomed. 309 00:20:08,330 --> 00:20:10,666 What you're left over with is two incredibly 310 00:20:10,667 --> 00:20:13,838 compact dramatic objects spiraling around each other. 311 00:20:16,840 --> 00:20:19,644 Over time they move in together, 312 00:20:19,645 --> 00:20:22,212 until finally they can coalesce 313 00:20:22,213 --> 00:20:25,284 in the most violent explosion since the big bang. 314 00:20:30,289 --> 00:20:34,792 The explosion is called a neutron star merger. 315 00:20:34,794 --> 00:20:38,564 The amount of energy in this explosion is crushing. 316 00:20:38,565 --> 00:20:40,733 There is almost no way to describe it. 317 00:20:40,734 --> 00:20:43,136 It's like taking all of the sun's energy 318 00:20:43,137 --> 00:20:45,406 that it will ever emit over its entire lifetime 319 00:20:45,407 --> 00:20:47,777 and releasing it in a single second. 320 00:20:53,114 --> 00:20:56,116 Berger suspects this colossal explosion 321 00:20:56,117 --> 00:20:59,555 forges iridium, gold and lead. 322 00:20:59,556 --> 00:21:03,893 But to rewrite the textbooks, he needs hard evidence. 323 00:21:03,894 --> 00:21:07,194 It was difficult to, uh, convince the community that this 324 00:21:07,195 --> 00:21:10,299 was a potential channel for the production of heavy elements. 325 00:21:14,704 --> 00:21:17,575 The proof is to actually see this process happening 326 00:21:17,576 --> 00:21:19,077 in the universe. 327 00:21:22,280 --> 00:21:24,147 June 2013... 328 00:21:24,148 --> 00:21:27,952 NASA's swift satellite spots a short burst of gamma rays 329 00:21:27,953 --> 00:21:31,256 from a nearby galaxy, 330 00:21:31,257 --> 00:21:36,963 a sure sign that a neutron star merger has just taken place. 331 00:21:36,964 --> 00:21:41,134 For Berger, it's the lucky break he's been waiting for. 332 00:21:41,134 --> 00:21:42,868 As soon as we knew that there was 333 00:21:42,869 --> 00:21:44,905 a gamma-ray burst nearby, 334 00:21:44,906 --> 00:21:49,076 we knew that this was our one chance for perhaps several years 335 00:21:49,077 --> 00:21:51,912 to obtain the right kind of measurements 336 00:21:51,913 --> 00:21:54,250 to test the formation of heavy elements. 337 00:21:56,219 --> 00:21:58,654 Once swift had identified the burst, 338 00:21:58,655 --> 00:22:03,127 the hubble space telescope swung into action to capture images. 339 00:22:06,296 --> 00:22:08,798 We grabbed them right away, and we just looked. 340 00:22:08,798 --> 00:22:10,333 We knew exactly where to look... 341 00:22:10,334 --> 00:22:12,201 At the center of this red circle. 342 00:22:12,202 --> 00:22:15,239 And what we saw was this source right there in the middle 343 00:22:15,240 --> 00:22:18,776 that is the direct signature of the production 344 00:22:18,777 --> 00:22:21,413 of very heavy elements, including gold. 345 00:22:25,352 --> 00:22:27,286 Berger's theory was right. 346 00:22:27,287 --> 00:22:31,825 But the rate of production was way higher than he'd expected. 347 00:22:31,826 --> 00:22:33,259 Well, in that one event, 348 00:22:33,259 --> 00:22:34,759 the amount of gold that was produced 349 00:22:34,760 --> 00:22:37,097 was more than the mass of the Earth. 350 00:22:38,634 --> 00:22:41,000 If we can bring it all here, it would be worth 351 00:22:41,001 --> 00:22:43,770 quadrillions and quadrillions of dollars. 352 00:22:45,375 --> 00:22:47,241 The theory is still very new, 353 00:22:47,242 --> 00:22:50,711 but it's possible that ancient neutron star mergers 354 00:22:50,712 --> 00:22:53,848 made all the heavy metals we see in the world today, 355 00:22:53,849 --> 00:22:58,121 including the last remaining ingredients for our car. 356 00:23:07,030 --> 00:23:11,270 But all these elements are still floating free in space. 357 00:23:13,305 --> 00:23:16,740 What's needed now is to pull them all together 358 00:23:16,741 --> 00:23:20,314 into one giant fabrication plant... 359 00:23:23,115 --> 00:23:24,916 The Earth. 360 00:23:37,455 --> 00:23:39,590 This is what your car looked like 361 00:23:39,592 --> 00:23:41,925 before the Earth was born... 362 00:23:41,926 --> 00:23:46,066 Just a vast, swirling cloud of gas and stardust, 363 00:23:46,067 --> 00:23:50,202 the exploded remains of ancient stars. 364 00:23:50,203 --> 00:23:52,770 The clouds between the stars of the galaxy 365 00:23:52,771 --> 00:23:54,942 are made of everything that the Earth, 366 00:23:54,943 --> 00:23:56,676 your body, and your car is made of. 367 00:23:56,677 --> 00:23:59,880 There's everything that you need floating in gaseous form 368 00:23:59,881 --> 00:24:01,249 between the stars. 369 00:24:03,118 --> 00:24:05,185 Four and a half billion years ago, 370 00:24:05,186 --> 00:24:08,457 the gas and dust collapse once more. 371 00:24:10,092 --> 00:24:15,430 It ignites explosively to create a new star... our Sun. 372 00:24:15,431 --> 00:24:17,566 Close to the young Sun, 373 00:24:17,567 --> 00:24:19,667 all of the lighter stuff got blown away. 374 00:24:19,669 --> 00:24:22,673 What was left behind was the heavier, denser stuff. 375 00:24:25,042 --> 00:24:27,444 There was carbon. There was iron. 376 00:24:27,445 --> 00:24:29,848 There was gold... Everything in between. 377 00:24:32,785 --> 00:24:35,386 Over time, these free-floating elements 378 00:24:35,387 --> 00:24:37,154 begin to coalesce. 379 00:24:37,155 --> 00:24:39,257 Dust becomes rock. 380 00:24:39,258 --> 00:24:44,229 Rocks join to form larger objects called planetesimals. 381 00:24:44,230 --> 00:24:48,403 Finally, planetesimals joined to form the Earth. 382 00:24:53,307 --> 00:24:58,613 Our planet is born with all the ingredients to build a car. 383 00:24:58,614 --> 00:25:03,554 But those ingredients are about to go their separate ways. 384 00:25:05,020 --> 00:25:07,288 The Earth is a big planet. 385 00:25:07,289 --> 00:25:09,022 And it's done something that not all planets do... 386 00:25:09,023 --> 00:25:12,828 It's differentiated. It melted. 387 00:25:12,829 --> 00:25:15,597 Copper and lead dissolve in sulfur 388 00:25:15,598 --> 00:25:18,599 and float to the top of the molten Earth, 389 00:25:18,601 --> 00:25:22,105 making these metals easy to mine today. 390 00:25:24,275 --> 00:25:27,778 But precious metals like iridium and gold 391 00:25:27,778 --> 00:25:29,780 sink to the core of the Earth, 392 00:25:29,781 --> 00:25:33,050 and most of the iron sinks with it. 393 00:25:33,051 --> 00:25:35,253 It's kind of a pain, actually. All the heavy elements 394 00:25:35,255 --> 00:25:36,854 that are super useful, like iron, 395 00:25:36,855 --> 00:25:38,356 they've sunk to the middle of the Earth, 396 00:25:38,357 --> 00:25:39,925 where we can't reach them. 397 00:25:39,926 --> 00:25:41,929 And there's not a whole lot of it in the crust. 398 00:25:47,834 --> 00:25:51,439 3.8 billion years ago, the oceans form, 399 00:25:51,440 --> 00:25:54,374 and water dissolves the last remaining traces 400 00:25:54,375 --> 00:25:57,545 of iron from the Earth's surface. 401 00:25:57,546 --> 00:25:59,448 In fact, there was so much iron in the sea 402 00:25:59,449 --> 00:26:01,415 that the Earth would have been green, 403 00:26:01,416 --> 00:26:04,353 not blue like it is today. 404 00:26:04,354 --> 00:26:06,888 The Earth's crust seems destined to be 405 00:26:06,890 --> 00:26:08,891 practically iron-free. 406 00:26:08,892 --> 00:26:15,767 Then, along comes the most unlikely savior... green slime. 407 00:26:17,733 --> 00:26:20,605 I want to show you a couple of examples of rocks 408 00:26:20,605 --> 00:26:23,641 that we recently brought back from South Africa. 409 00:26:23,642 --> 00:26:26,477 Caltech geobiologist Woody fischer 410 00:26:26,478 --> 00:26:28,378 traces the history of iron 411 00:26:28,380 --> 00:26:31,082 through the Earth's earliest rocks. 412 00:26:31,083 --> 00:26:33,818 This is an example of a rock that was deposited 413 00:26:33,819 --> 00:26:36,520 on the sea floor a little over 21/2 billion years ago. 414 00:26:36,521 --> 00:26:38,691 And there's not a lot of iron in this sample. 415 00:26:38,692 --> 00:26:42,162 Now what's so interesting is, you go to the same place 416 00:26:42,163 --> 00:26:45,197 on the Earth 200 million years later, 417 00:26:45,198 --> 00:26:48,000 and what you find is that things have really changed. 418 00:26:48,001 --> 00:26:50,770 And you'll note this very rusty color to it. 419 00:26:50,771 --> 00:26:53,240 This is from the presence of iron oxides. 420 00:26:53,240 --> 00:26:58,712 And in fact the rock itself is incredibly heavy, very dense. 421 00:26:58,713 --> 00:27:01,115 Why does the Earth's geological record 422 00:27:01,116 --> 00:27:05,387 change so quickly and so profoundly? 423 00:27:05,388 --> 00:27:09,390 One clue is that the sudden appearance of iron-rich rocks 424 00:27:09,391 --> 00:27:13,699 coincides with the rise of the first simple plants. 425 00:27:15,565 --> 00:27:19,567 This is a micro-organism called a cyanobacterium. 426 00:27:19,568 --> 00:27:22,306 Each of the individual cells that are present in that medium 427 00:27:22,307 --> 00:27:25,008 are green, and they're conducting photosynthesis. 428 00:27:25,009 --> 00:27:30,213 This group cyanobacteria is gathering energy from light, 429 00:27:30,214 --> 00:27:32,316 using that to split water. 430 00:27:32,317 --> 00:27:36,323 And in so doing, they produce copious amounts of oxygen. 431 00:27:40,394 --> 00:27:43,462 In the early oceans, this newly formed oxygen 432 00:27:43,463 --> 00:27:45,965 quickly binds to the dissolved iron, 433 00:27:45,967 --> 00:27:50,269 forming a heavy rust that settles on the ocean floor. 434 00:27:50,270 --> 00:27:52,806 For the first time in Earth's history, there was oxygen... 435 00:27:52,807 --> 00:27:56,711 Free oxygen in the air. That combined with the iron. 436 00:27:56,712 --> 00:27:59,482 And the iron basically sank to the bottom of the ocean. 437 00:28:01,884 --> 00:28:04,220 These ancient, rusty deposits 438 00:28:04,221 --> 00:28:07,521 formed the iron ore we dig out of the ground 439 00:28:07,522 --> 00:28:10,960 to make cars 2 billion years later. 440 00:28:10,961 --> 00:28:13,096 So in the process of making a car, 441 00:28:13,097 --> 00:28:14,830 mining the iron ore, 442 00:28:14,832 --> 00:28:17,435 life was an essential part of that first step. 443 00:28:19,203 --> 00:28:22,106 You have to wait until after these guys evolve 444 00:28:22,107 --> 00:28:24,241 in order to be able to concentrate 445 00:28:24,242 --> 00:28:25,979 the raw materials that you need. 446 00:28:34,487 --> 00:28:37,422 The life of early plants brought us iron. 447 00:28:37,423 --> 00:28:41,362 But their death is perhaps even more helpful 448 00:28:41,363 --> 00:28:46,402 because without dead plants, your car isn't going anywhere. 449 00:28:48,537 --> 00:28:50,237 So, what's the final ingredient 450 00:28:50,238 --> 00:28:52,940 for getting a car to actually go? 451 00:28:52,941 --> 00:28:54,808 You need to add fuel. 452 00:28:54,809 --> 00:28:57,813 And we, right now, use hydrocarbon-based fuel. 453 00:28:57,814 --> 00:29:00,015 We use oil. 454 00:29:00,016 --> 00:29:04,153 Oil is actually the remnant of dead plant life 455 00:29:04,154 --> 00:29:07,190 from billions of years ago. 456 00:29:07,191 --> 00:29:09,993 It amazes me to think that, as you're driving your car around, 457 00:29:09,994 --> 00:29:15,365 what you're actually running the car on is ancient dead life. 458 00:29:15,366 --> 00:29:18,536 These hydrocarbons are also processed 459 00:29:18,537 --> 00:29:22,642 to help make rubber and plastics for the tires and interior trim. 460 00:29:29,648 --> 00:29:32,550 Now we have almost all of the components needed 461 00:29:32,551 --> 00:29:34,720 to complete a car. 462 00:29:34,721 --> 00:29:40,326 All that remains is a spark to bring the engine to life. 463 00:29:40,327 --> 00:29:42,461 But to get that spark, 464 00:29:42,462 --> 00:29:46,166 the Earth must pay a catastrophic price. 465 00:29:59,000 --> 00:30:01,402 65 million years ago, 466 00:30:01,403 --> 00:30:04,372 the Earth's crust had all the materials needed 467 00:30:04,373 --> 00:30:07,608 to build a car except for one crucial group 468 00:30:07,609 --> 00:30:10,146 of supertough metals. 469 00:30:11,680 --> 00:30:13,682 This is a spark plug. 470 00:30:13,682 --> 00:30:17,653 And the way it works is that 100,000 volts are put across 471 00:30:17,653 --> 00:30:18,672 this gap here. 472 00:30:19,690 --> 00:30:23,893 And that ignites gasoline vapor in the cylinder of your motor. 473 00:30:25,328 --> 00:30:28,365 This tip has to survive in very harsh conditions. 474 00:30:30,103 --> 00:30:34,672 So it must be made of a very, very sturdy, robust material. 475 00:30:34,673 --> 00:30:36,941 And the material in this spark plug 476 00:30:36,942 --> 00:30:38,980 is a metal known as iridium. 477 00:30:42,582 --> 00:30:45,416 Like other heavy metals such as gold and lead, 478 00:30:45,417 --> 00:30:48,520 iridium is born inside the exploded remains 479 00:30:48,521 --> 00:30:51,289 of neutron stars. 480 00:30:51,290 --> 00:30:55,128 And when the Earth forms, plenty of iridium is in the mix. 481 00:30:55,130 --> 00:30:57,798 But it quickly sinks out of reach 482 00:30:57,799 --> 00:31:00,036 while the Earth is still molten, 483 00:31:00,037 --> 00:31:04,105 falling to the core under the influence of gravity. 484 00:31:04,106 --> 00:31:07,877 So, where does the iridium come from that we mine today? 485 00:31:12,648 --> 00:31:17,085 This exposed rock face in Colorado reveals a clue, 486 00:31:17,086 --> 00:31:20,991 a mysterious layer in the Earth's geological record 487 00:31:20,992 --> 00:31:23,727 that wraps around the entire planet. 488 00:31:23,728 --> 00:31:25,329 There's something particularly interesting 489 00:31:25,330 --> 00:31:27,031 about this Clay layer here. 490 00:31:27,032 --> 00:31:29,434 If you analyze the concentration of rare metals 491 00:31:29,435 --> 00:31:31,270 like iridium in this layer, 492 00:31:31,271 --> 00:31:34,172 you'll find that there's about 100 times as much iridium here 493 00:31:34,173 --> 00:31:37,476 as in the other rocks around us in the crust of the Earth. 494 00:31:37,477 --> 00:31:40,079 It's rather bizarre, actually, to find so much iridium 495 00:31:40,080 --> 00:31:42,949 concentrated in one place here in crustal rocks. 496 00:31:42,950 --> 00:31:45,852 And it turns out that the entire budget of the iridium 497 00:31:45,853 --> 00:31:48,222 in the Earth's crust is pretty much contained in this layer. 498 00:31:51,192 --> 00:31:53,460 When geologists discovered the iridium layer 499 00:31:53,461 --> 00:31:56,262 in the late '70s, it became one of the biggest 500 00:31:56,263 --> 00:31:58,767 mysteries in science. 501 00:31:58,768 --> 00:32:02,604 How could so much of this rare metal end up 502 00:32:02,605 --> 00:32:06,041 concentrated in such a thin layer? 503 00:32:08,711 --> 00:32:12,181 Only astronomers had measured such high concentrations 504 00:32:12,182 --> 00:32:15,116 of iridium before, inside rocks 505 00:32:15,117 --> 00:32:18,654 originating in the asteroid belt. 506 00:32:18,655 --> 00:32:20,691 Billions of years ago, planets were forming 507 00:32:20,692 --> 00:32:22,326 all over our solar system. 508 00:32:22,327 --> 00:32:24,997 But there was an area in between Mars and Jupiter 509 00:32:24,998 --> 00:32:27,631 where the gravity of Jupiter pretty much pulled apart 510 00:32:27,632 --> 00:32:29,299 anything that tried to form. 511 00:32:29,300 --> 00:32:32,270 And what got left over were a bunch of large, rocky chunks 512 00:32:32,271 --> 00:32:34,606 that we call the asteroid belt. 513 00:32:34,607 --> 00:32:38,344 Now, some of the asteroid belt is made of rock. 514 00:32:38,345 --> 00:32:41,315 Other asteroids are richer in metals. 515 00:32:43,617 --> 00:32:45,251 From time to time, 516 00:32:45,252 --> 00:32:47,521 asteroids can get thrown out of orbit 517 00:32:47,522 --> 00:32:52,859 by another asteroid, or by the long reach of Jupiter's gravity. 518 00:32:52,861 --> 00:32:57,732 And sometimes, they smash into the Earth. 519 00:32:57,733 --> 00:33:00,001 Is it possible the iridium layer was simply 520 00:33:00,002 --> 00:33:02,903 the scattered remains of a single, giant 521 00:33:02,904 --> 00:33:05,775 metal-rich asteroid impact? 522 00:33:05,776 --> 00:33:09,247 30 years ago, this sounded like a crazy idea. 523 00:33:11,213 --> 00:33:13,718 Only an asteroid the size of a city 524 00:33:13,719 --> 00:33:15,384 would have had enough power 525 00:33:15,385 --> 00:33:18,522 to blast debris around the entire planet. 526 00:33:24,230 --> 00:33:26,798 If you can imagine the magnitude, the enormity 527 00:33:26,798 --> 00:33:28,700 of the violence of an event like that, 528 00:33:28,701 --> 00:33:31,971 and to have inches of dusty debris 529 00:33:31,971 --> 00:33:34,506 come booming over the horizon and settling out of the sky 530 00:33:34,507 --> 00:33:37,910 and raining on top of you and burying you in this layer, 531 00:33:37,911 --> 00:33:41,148 that should make a pretty big crater someplace on the Earth. 532 00:33:42,451 --> 00:33:43,750 Although it sounded crazy, 533 00:33:43,751 --> 00:33:46,618 the asteroid hypothesis also solved 534 00:33:46,619 --> 00:33:49,589 a longstanding mystery. 535 00:33:49,590 --> 00:33:53,660 The dinosaurs were wiped out around the same time 536 00:33:53,661 --> 00:33:55,663 the iridium layer was laid down. 537 00:33:57,266 --> 00:33:59,769 Could the two events be linked? 538 00:33:59,769 --> 00:34:03,038 The puzzle was solved when an asteroid impact crater 539 00:34:03,038 --> 00:34:05,674 was discovered down in the Yucatan. 540 00:34:05,675 --> 00:34:08,777 The crater age turned out to be exactly 65 million years old, 541 00:34:08,777 --> 00:34:10,746 the same age as this deposit. 542 00:34:10,746 --> 00:34:14,418 And the crater's size turned out to be just the size 543 00:34:14,418 --> 00:34:17,420 of crater you would get from the size of an asteroid 544 00:34:17,422 --> 00:34:19,822 it would take to make this layer. 545 00:34:19,824 --> 00:34:23,027 So it turns out that, in a lot of ways, you can think 546 00:34:23,027 --> 00:34:25,730 of asteroids as sort of a cosmic iridium-delivery system 547 00:34:25,731 --> 00:34:27,865 for us here on the surface of the Earth. 548 00:34:27,867 --> 00:34:29,802 And it's not just iridium 549 00:34:29,802 --> 00:34:31,739 we have to thank asteroids for. 550 00:34:31,739 --> 00:34:33,639 There were probably several times 551 00:34:33,639 --> 00:34:35,440 in the history of our solar system where there was 552 00:34:35,442 --> 00:34:37,945 heavy bombardment, all kinds of asteroids and comets 553 00:34:37,945 --> 00:34:39,846 falling in towards the Earth. 554 00:34:39,847 --> 00:34:42,449 Well, the Earth had solidified to some degree by that time. 555 00:34:42,451 --> 00:34:45,018 So not everything sank down into the core. 556 00:34:45,018 --> 00:34:47,355 So some of the metals we find around us 557 00:34:47,356 --> 00:34:49,824 are products of this later era of bombardment. 558 00:34:53,260 --> 00:34:55,764 The Earth's history is a violent one. 559 00:34:55,766 --> 00:34:58,768 Over the course of time, we have been hit over and over 560 00:34:58,769 --> 00:35:01,838 and over again by asteroids of all sizes. 561 00:35:01,838 --> 00:35:04,708 Some of them have actually delivered quite a bit 562 00:35:04,708 --> 00:35:06,610 of heavy elements to the surface of the Earth. 563 00:35:09,036 --> 00:35:11,036 These asteroid-borne materials 564 00:35:11,038 --> 00:35:14,405 include most of the gold, platinum and nickel 565 00:35:14,407 --> 00:35:16,242 we use in cars today. 566 00:35:18,043 --> 00:35:22,014 Asteroid impacts will form little pockets of concentrations 567 00:35:22,014 --> 00:35:24,985 of some of those ore minerals and ore metals for us 568 00:35:24,985 --> 00:35:28,420 that we can then mine in greater abundance on the surface. 569 00:35:28,422 --> 00:35:31,057 In many cases, when you go to a mine to dig up 570 00:35:31,059 --> 00:35:33,561 these heavy elements, what you are doing 571 00:35:33,563 --> 00:35:36,297 is tapping into an asteroid impact. 572 00:35:42,605 --> 00:35:44,606 Metal-rich asteroids are the final piece 573 00:35:44,606 --> 00:35:46,076 of the puzzle. 574 00:35:47,545 --> 00:35:50,079 We can now reconstruct the journey of every atom 575 00:35:50,081 --> 00:35:53,481 of our car through time and space 576 00:35:53,483 --> 00:35:55,684 from the moment of the big bang 577 00:35:55,686 --> 00:35:59,657 through generations of stars to the birth of the Earth 578 00:35:59,657 --> 00:36:03,695 and, eventually, the showroom floor. 579 00:36:03,695 --> 00:36:06,699 Over the course of the multiple supernovae 580 00:36:06,701 --> 00:36:10,400 in our universe and the birth and death of stars, 581 00:36:10,402 --> 00:36:13,273 we were able to collect all of the materials needed 582 00:36:13,273 --> 00:36:16,476 to assemble these cars. 583 00:36:16,476 --> 00:36:17,945 That's pretty fantastic. 584 00:36:20,581 --> 00:36:23,885 I think we don't fully appreciate how complicated 585 00:36:23,885 --> 00:36:25,887 the elements that make up our car really are 586 00:36:25,887 --> 00:36:29,490 and how special they are. They really are star stuff. 587 00:36:39,501 --> 00:36:41,302 But not every car is like the one 588 00:36:41,304 --> 00:36:43,804 we've just pulled apart. 589 00:36:43,806 --> 00:36:47,344 These days, not every car runs on gas. 590 00:36:49,447 --> 00:36:53,449 And electric vehicles require a magical element 591 00:36:53,449 --> 00:36:57,489 that's made in space by cosmic ray guns. 592 00:37:05,864 --> 00:37:09,835 This car doesn't have a gas tank. 593 00:37:09,835 --> 00:37:13,909 It's part of a new generation of electric vehicles. 594 00:37:17,411 --> 00:37:19,445 The key to these high-tech cars 595 00:37:19,445 --> 00:37:21,815 are their rechargeable batteries, 596 00:37:21,817 --> 00:37:26,054 a technology that relies on one of the Earth's rarest metals. 597 00:37:28,090 --> 00:37:31,260 This here is a battery pack from an electric car. 598 00:37:31,262 --> 00:37:35,096 And in today's electric cars, the metal of choice is lithium. 599 00:37:35,097 --> 00:37:39,603 And lithium has one of the most amazing stories in the universe. 600 00:37:42,273 --> 00:37:45,041 After hydrogen and helium, 601 00:37:45,043 --> 00:37:47,510 lithium is the lightest element, 602 00:37:47,512 --> 00:37:50,748 with just three protons and four neutrons. 603 00:37:50,748 --> 00:37:54,851 Its lightness makes it ideal for electric cars. 604 00:37:54,851 --> 00:37:58,389 If the battery weighs more than the car, then we are just 605 00:37:58,391 --> 00:38:00,592 wasting energy on moving the battery around. 606 00:38:00,594 --> 00:38:02,762 If we can build a light battery, 607 00:38:02,762 --> 00:38:04,797 for example a lithium-ion battery, 608 00:38:04,797 --> 00:38:08,201 then we can provide the power without the penalty 609 00:38:08,202 --> 00:38:10,269 of having to carry those heavy batteries 610 00:38:10,271 --> 00:38:11,572 along with the car. 611 00:38:13,942 --> 00:38:15,577 Lithium is rapidly becoming 612 00:38:15,577 --> 00:38:18,311 one of the most sought-after metals on Earth. 613 00:38:18,311 --> 00:38:21,548 But it's also a cosmic curiosity. 614 00:38:23,552 --> 00:38:26,221 The big bang creates a trace of lithium. 615 00:38:26,222 --> 00:38:31,260 But as the first stars form, this lithium disappears. 616 00:38:31,260 --> 00:38:34,264 Unlike hydrogen and helium, which are fairly stable 617 00:38:34,264 --> 00:38:37,967 on an atomic scale, lithium is a little bit fragile. 618 00:38:37,967 --> 00:38:40,838 It can actually be broken apart into its components. 619 00:38:42,472 --> 00:38:46,041 As time goes by, these first stars manufacture 620 00:38:46,043 --> 00:38:50,715 a little lithium on their own, but it doesn't last long. 621 00:38:50,715 --> 00:38:53,518 It is so fragile that, the instant it's made, 622 00:38:53,518 --> 00:38:55,653 it's destroyed once again by the conditions 623 00:38:55,655 --> 00:38:58,590 in the core of the star. 624 00:38:58,592 --> 00:39:01,893 So, how does the universe fuse together atoms 625 00:39:01,894 --> 00:39:03,460 to form lithium? 626 00:39:03,461 --> 00:39:05,931 Surprisingly, it doesn't. 627 00:39:05,931 --> 00:39:07,768 It blasts them apart. 628 00:39:12,039 --> 00:39:13,907 The answer for where lithium comes from 629 00:39:13,909 --> 00:39:15,507 is an amazing thing. 630 00:39:15,509 --> 00:39:17,210 It's almost like a Sci-Fi answer. 631 00:39:17,211 --> 00:39:19,914 It kind of comes from ray guns from space. 632 00:39:26,987 --> 00:39:29,423 The ray guns are supernovas. 633 00:39:29,425 --> 00:39:34,164 And their bullets are cosmic rays, high-velocity particles 634 00:39:34,164 --> 00:39:38,266 that streak through space at close to the speed of light. 635 00:39:38,268 --> 00:39:40,971 Cosmic rays are subatomic particles. 636 00:39:40,972 --> 00:39:44,539 They are atomic nuclei that are accelerated to high speed 637 00:39:44,541 --> 00:39:47,376 in a supernova explosion. 638 00:39:47,378 --> 00:39:50,648 If another atomic nucleus gets in the way, it can hit them 639 00:39:50,648 --> 00:39:52,150 and shatter them. 640 00:39:52,150 --> 00:39:54,686 And one of the pieces of shrapnel from this explosion 641 00:39:54,686 --> 00:39:56,623 is lithium. 642 00:40:05,371 --> 00:40:08,273 The process is a bit like going bowling, where the bowling ball 643 00:40:08,273 --> 00:40:11,510 is the cosmic ray, and the pins together are some other 644 00:40:11,510 --> 00:40:13,313 atomic nucleus. 645 00:40:19,887 --> 00:40:23,157 When the bowling ball smashes into the pins, 646 00:40:23,157 --> 00:40:25,827 it sends them scattered in all directions. 647 00:40:29,297 --> 00:40:31,768 And one of those pins could be lithium. 648 00:40:44,114 --> 00:40:46,648 Cosmic rays are traveling throughout all of space, 649 00:40:46,648 --> 00:40:48,485 between galaxies and in galaxies. 650 00:40:48,487 --> 00:40:50,554 So the cosmic rays that are forming lithium 651 00:40:50,556 --> 00:40:52,456 by breaking other elements apart 652 00:40:52,458 --> 00:40:55,460 are literally doing it in the space between the stars. 653 00:40:57,097 --> 00:40:59,431 Almost all the lithium on Earth today 654 00:40:59,431 --> 00:41:03,835 was made this way, atom by atom in the vastness of space, 655 00:41:03,835 --> 00:41:06,838 and then swept up into the clouds of gas 656 00:41:06,840 --> 00:41:08,842 that formed our solar system. 657 00:41:15,983 --> 00:41:17,784 Oh, yeah, baby. 658 00:41:17,784 --> 00:41:22,322 For our cosmic car, this may look like the end of the line. 659 00:41:22,324 --> 00:41:25,025 But the production line for the universe, 660 00:41:25,027 --> 00:41:27,994 that keeps on rolling. 661 00:41:27,996 --> 00:41:29,429 This is pretty awesome. 662 00:41:29,431 --> 00:41:32,099 These atoms in this car here have been traveling 663 00:41:32,101 --> 00:41:33,603 across the cosmos. 664 00:41:33,603 --> 00:41:36,306 They came to us from maybe 13 billion years ago, 665 00:41:36,306 --> 00:41:38,974 a billion years after the formation of the universe. 666 00:41:38,976 --> 00:41:40,710 And now, guess what? They were used, 667 00:41:40,711 --> 00:41:42,681 and we're returning them back to where they came from. 668 00:41:44,414 --> 00:41:47,284 The atoms in our car will not be in our car forever. 669 00:41:47,284 --> 00:41:49,452 In fact, our car will probably be destroyed 670 00:41:49,454 --> 00:41:51,288 within a single human lifetime. 671 00:41:51,289 --> 00:41:52,755 Time to crush. 672 00:41:52,757 --> 00:41:54,990 It'll be recycled into other things on Earth. 673 00:41:54,992 --> 00:41:57,963 But eventually, even the atoms on Earth will be recycled 674 00:41:57,963 --> 00:41:59,565 with the rest of the cosmos. 675 00:42:04,503 --> 00:42:05,940 How cool was that? 676 00:42:07,708 --> 00:42:11,844 You could imagine my car gets destroyed with the Earth, 677 00:42:11,846 --> 00:42:14,581 and eventually it makes its way to another planet. 678 00:42:14,581 --> 00:42:17,884 It gets built into some other kind of transportation mode 679 00:42:17,885 --> 00:42:20,755 by an alien race... I mean, that's totally possible. 680 00:42:20,755 --> 00:42:24,161 And I think that's kind of a cool idea. 681 00:42:26,596 --> 00:42:29,264 From stars being born billions of years ago 682 00:42:29,266 --> 00:42:32,969 to cosmic rays to even the big bang itself, 683 00:42:32,969 --> 00:42:35,172 it's amazing to contemplate all of the things 684 00:42:35,172 --> 00:42:37,005 that had to come together in the universe 685 00:42:37,005 --> 00:42:38,773 for us to have cars. 686 00:42:38,773 --> 00:42:40,476 You really are driving around 687 00:42:40,478 --> 00:42:42,612 in the end product of something that started 688 00:42:42,614 --> 00:42:44,880 13.7 billion years ago. 689 00:42:44,882 --> 00:42:46,748 That new-car smell? 690 00:42:46,750 --> 00:42:49,688 That's actually old-universe smell 691 00:42:49,688 --> 00:42:52,858 because that smell is traceable all the way back 692 00:42:52,860 --> 00:42:55,527 to the big bang. 693 00:42:55,527 --> 00:42:58,362 How you like that? 694 00:42:58,364 --> 00:43:01,034 That guarantees the last word in a... in a show. 695 00:43:01,034 --> 00:43:02,135 Okay, yeah. 56780

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