1 00:00:02,703 --> 00:00:05,365 Narrator: This is an exploding star. 2 00:00:05,372 --> 00:00:07,864 It's called a supernova. 3 00:00:12,780 --> 00:00:15,943 Kaku: A supernova is the greatest cataclysm 4 00:00:15,950 --> 00:00:18,885 in the history of the entire universe. 5 00:00:18,886 --> 00:00:23,346 Narrator: Supernovas come in different sizes and types. 6 00:00:23,357 --> 00:00:25,189 All of them are so bright, 7 00:00:25,192 --> 00:00:28,719 they can be seen across the universe. 8 00:00:28,729 --> 00:00:32,097 A supernova is the most violent death of a star you can imagine. 9 00:00:34,535 --> 00:00:37,596 Narrator: But this violent destruction of a star 10 00:00:37,605 --> 00:00:41,735 is also the birth of everything we see around us. 11 00:00:57,358 --> 00:01:02,956 Really big stars go out with a bang, called a supernova. 12 00:01:02,963 --> 00:01:06,399 A supernova can outshine an entire galaxy, 13 00:01:06,400 --> 00:01:10,371 releasing trillions of times the energy of our Sun. 14 00:01:19,747 --> 00:01:21,681 Narrator: They're so violent, 15 00:01:21,682 --> 00:01:25,312 if one of them exploded just a few dozen light-years away, 16 00:01:25,319 --> 00:01:27,879 planet Earth would be toast. 17 00:01:37,565 --> 00:01:41,297 A nearby supernova would really ruin our day. 18 00:01:43,737 --> 00:01:45,171 First of all, 19 00:01:45,172 --> 00:01:49,541 the sudden burst of radiation would scorch the atmosphere. 20 00:01:49,543 --> 00:01:53,104 The only place to go is underground. 21 00:01:53,113 --> 00:01:54,410 Underground, 22 00:01:54,415 --> 00:01:57,840 you could then withstand the blistering burst of x-rays 23 00:01:57,851 --> 00:01:59,319 which hit the Earth. 24 00:01:59,320 --> 00:02:02,187 And then it would scorch all plant life. 25 00:02:02,189 --> 00:02:04,521 And with the collapse of the food chain, 26 00:02:04,525 --> 00:02:07,483 we're talking about a possible extinction on the Earth. 27 00:02:11,932 --> 00:02:14,799 Narrator: Supernovas are killers. 28 00:02:19,974 --> 00:02:24,468 But they also create the basic elements that make up our world. 29 00:02:28,582 --> 00:02:30,744 Our planet, our star, everything around us 30 00:02:30,751 --> 00:02:34,278 formed out of the debris of a dead exploded star. 31 00:02:34,288 --> 00:02:38,953 Everything that makes up our bodies and the skyline 32 00:02:38,959 --> 00:02:40,927 came from supernovae. 33 00:02:43,364 --> 00:02:45,890 All of the iron, all of the silicon, 34 00:02:45,899 --> 00:02:49,267 all of the elements that went into these buildings. 35 00:02:49,269 --> 00:02:51,636 The things that make up my blood, my body, 36 00:02:51,639 --> 00:02:53,334 the gold in my wedding ring -- 37 00:02:53,340 --> 00:02:56,310 everything you see here is a supernova. 38 00:03:04,785 --> 00:03:07,311 Narrator: But our Sun won't become a supernova. 39 00:03:07,321 --> 00:03:08,618 It's too small. 40 00:03:20,768 --> 00:03:25,865 Like all stars, it's basically a giant nuclear reactor. 41 00:03:28,709 --> 00:03:32,407 The fusion reactor inside a star burns hydrogen, 42 00:03:32,413 --> 00:03:35,110 the simplest, most common element. 43 00:03:38,852 --> 00:03:42,413 The reaction fuses hydrogen atoms together... 44 00:03:44,258 --> 00:03:46,989 ...producing helium and energy. 45 00:03:53,000 --> 00:03:55,469 And when the hydrogen runs out, 46 00:03:55,469 --> 00:03:59,406 stars keep burning by fusing helium into carbon... 47 00:04:00,674 --> 00:04:03,700 ...then carbon into oxygen. 48 00:04:06,580 --> 00:04:09,515 When small stars like our Sun make carbon, 49 00:04:09,516 --> 00:04:11,814 they begin to die. 50 00:04:11,819 --> 00:04:14,049 Dr. Kirshner: During the lifetime of a star, 51 00:04:14,054 --> 00:04:16,148 there's a balance between gravity pulling in 52 00:04:16,156 --> 00:04:17,555 and pressure pushing out. 53 00:04:17,558 --> 00:04:20,960 For a star that's generating energy, there's no problem. 54 00:04:20,961 --> 00:04:24,261 But once energy generation switches off, 55 00:04:24,264 --> 00:04:27,598 the pressure goes away, and gravity wins. 56 00:04:29,770 --> 00:04:34,003 Narrator: Now gravity begins to crush the center of the star. 57 00:04:38,612 --> 00:04:42,446 The star's outer layers are pushed outwards. 58 00:04:44,251 --> 00:04:49,417 They expand into a huge ball of gas called a red giant. 59 00:04:51,692 --> 00:04:56,027 Our Sun, when it dies 41/2 to 5 billion years from now, 60 00:04:56,029 --> 00:04:58,589 its corona will go all the way out to Mars. 61 00:05:03,103 --> 00:05:07,199 Everything on the planet Earth will vaporize. 62 00:05:13,881 --> 00:05:16,441 Narrator: While the outer layers expand, 63 00:05:16,450 --> 00:05:18,009 in the center of the Sun, 64 00:05:18,018 --> 00:05:20,385 gravity will have the opposite effect. 65 00:05:25,559 --> 00:05:27,254 It'll crush the Sun's core 66 00:05:27,261 --> 00:05:30,128 to just a millionth of its original size -- 67 00:05:30,130 --> 00:05:31,894 about the size of the Earth. 68 00:05:34,034 --> 00:05:39,473 Now it's a dense ball of oxygen and carbon called a white dwarf. 69 00:05:45,345 --> 00:05:46,904 In our solar system, 70 00:05:46,914 --> 00:05:50,612 this will be the end of the story. 71 00:05:50,617 --> 00:05:54,611 The gas from the dying star will gradually disperse, 72 00:05:54,621 --> 00:05:58,888 but the tiny white dwarf will burn for billions of years. 73 00:06:04,398 --> 00:06:07,561 But our solar system is unusual. 74 00:06:07,568 --> 00:06:09,696 It has just one star. 75 00:06:15,776 --> 00:06:20,577 The fact is, the vast majority of stars orbit in pairs. 76 00:06:26,653 --> 00:06:30,624 When one of the two stars dies and becomes a white dwarf, 77 00:06:30,624 --> 00:06:32,183 if it's close enough, 78 00:06:32,192 --> 00:06:35,184 it starts stealing material from the other star. 79 00:06:45,739 --> 00:06:50,142 Kaku: Think of two stars rotating around each other. 80 00:06:50,143 --> 00:06:55,138 One star's slowly sucking all the hydrogen and helium 81 00:06:55,148 --> 00:06:56,582 from its companion star. 82 00:06:56,583 --> 00:06:59,917 It's like a vampire. 83 00:07:02,155 --> 00:07:05,090 Narrator: As the white dwarf sucks more and more fuel 84 00:07:05,092 --> 00:07:06,958 out of its companion star, 85 00:07:06,960 --> 00:07:10,897 it gets heavier and denser and less stable. 86 00:07:13,734 --> 00:07:18,831 Inside, carbon and oxygen atoms are about to fuse together, 87 00:07:18,839 --> 00:07:20,637 and that's bad news. 88 00:07:26,513 --> 00:07:30,245 Krauss: A white dwarf, in some sense, 89 00:07:30,250 --> 00:07:33,686 is like a bomb waiting to be lit. 90 00:07:33,687 --> 00:07:36,418 There's a huge amount of energy stored in that star -- 91 00:07:36,423 --> 00:07:38,482 gravitational energy and nuclear energy. 92 00:07:41,428 --> 00:07:44,921 Narrator: This white dwarf is turning into a monster -- 93 00:07:44,932 --> 00:07:48,596 a type 1A monster. 94 00:07:48,602 --> 00:07:50,195 A type 1A supernova 95 00:07:50,203 --> 00:07:53,002 is a 20-billion-billion-billion- megaton 96 00:07:53,006 --> 00:07:55,771 thermonuclear carbon bomb. 97 00:07:55,776 --> 00:07:59,007 It's one of the most explosive substances in the universe. 98 00:08:02,616 --> 00:08:04,106 Narrator: Eventually, 99 00:08:04,117 --> 00:08:07,985 the white dwarf drains so much material from its companion, 100 00:08:07,988 --> 00:08:09,922 it goes into nuclear overload. 101 00:08:15,495 --> 00:08:17,896 The carbon and oxygen inside it 102 00:08:17,898 --> 00:08:21,960 start to turn into a common but dangerous element -- 103 00:08:21,969 --> 00:08:24,495 at least to stars. 104 00:08:26,640 --> 00:08:28,438 Dr. Thaller: You've probably seen in "Star Trek" 105 00:08:28,442 --> 00:08:30,843 the idea that there is some sort of secret technology 106 00:08:30,844 --> 00:08:31,936 that kills a star. 107 00:08:31,945 --> 00:08:33,538 Well, I mean, it's in your frying pan 108 00:08:33,547 --> 00:08:35,811 that you used this morning for breakfast -- iron. 109 00:08:35,816 --> 00:08:39,343 Narrator: The moment the white-dwarf star 110 00:08:39,353 --> 00:08:43,881 starts to fuse carbon and oxygen into iron, it's doomed. 111 00:08:46,560 --> 00:08:50,360 Suddenly, the white dwarf explodes. 112 00:09:06,980 --> 00:09:10,280 Krauss: The nuclear explosion of a white dwarf include, 113 00:09:10,283 --> 00:09:12,843 among other things, huge amounts of iron. 114 00:09:12,853 --> 00:09:14,753 And, in fact, type 1A supernovae 115 00:09:14,755 --> 00:09:17,622 are of vital importance to populating the universe 116 00:09:17,624 --> 00:09:20,491 with the kind of elements that are important to us. 117 00:09:27,834 --> 00:09:33,329 Narrator: Type 1A supernovas blast iron trillions of miles into space. 118 00:09:34,975 --> 00:09:38,912 It's where most of the iron in the cosmos comes from. 119 00:09:44,017 --> 00:09:48,079 But what about all the elements that are heavier than iron, 120 00:09:48,088 --> 00:09:49,647 like gold and silver? 121 00:09:49,656 --> 00:09:51,385 Where do they come from? 122 00:09:51,391 --> 00:09:56,454 The answer, again, is other stars -- 123 00:09:56,463 --> 00:09:58,397 single stars, 124 00:09:58,398 --> 00:10:00,059 bigger stars. 125 00:10:12,479 --> 00:10:16,177 Narrator: Supernovas make everything in the universe. 126 00:10:16,183 --> 00:10:17,810 Everything we see, 127 00:10:17,818 --> 00:10:20,150 all the material in planet Earth, 128 00:10:20,153 --> 00:10:23,384 was created inside a supernova. 129 00:10:23,390 --> 00:10:28,123 Even you and I are made from dying stars. 130 00:10:28,128 --> 00:10:32,395 Krauss: Without supernovae, we wouldn't be here. 131 00:10:32,399 --> 00:10:37,667 Every atom in your body was once inside a star that exploded. 132 00:10:37,671 --> 00:10:39,161 And the atoms in your left hand 133 00:10:39,172 --> 00:10:41,004 may have come from a different star 134 00:10:41,007 --> 00:10:42,475 than the atoms in your right hand. 135 00:10:42,476 --> 00:10:44,069 You are literally stardust. 136 00:10:49,182 --> 00:10:52,174 Narrator: Almost all of the iron in our solar system 137 00:10:52,185 --> 00:10:54,483 came from a double-star supernova 138 00:10:54,488 --> 00:10:57,822 that exploded more than five billion years ago. 139 00:11:00,560 --> 00:11:04,292 From our planet's molten core... 140 00:11:04,297 --> 00:11:06,823 To our skyscrapers... 141 00:11:06,833 --> 00:11:10,235 To the hemoglobin in our blood... 142 00:11:12,506 --> 00:11:17,068 ...it's all made of iron from type 1A supernovas. 143 00:11:19,980 --> 00:11:22,711 But the heavier elements in our world, 144 00:11:22,716 --> 00:11:24,844 like gold, silver, and uranium, 145 00:11:24,851 --> 00:11:27,513 come from another type of supernova... 146 00:11:31,925 --> 00:11:34,860 ...a single-star supernova. 147 00:11:37,797 --> 00:11:40,960 This is our Sun. 148 00:11:40,967 --> 00:11:45,165 A single star has to weigh much more than our Sun 149 00:11:45,172 --> 00:11:46,606 to go supernova. 150 00:11:48,008 --> 00:11:51,876 And there are some monster stars out there. 151 00:11:55,015 --> 00:11:58,747 Some are dozens of times heavier than our Sun. 152 00:12:00,053 --> 00:12:03,921 And some are hundreds of times more massive. 153 00:12:07,861 --> 00:12:12,321 The heavier the star, the faster it burns. 154 00:12:12,332 --> 00:12:16,826 And when these massive stars begin to age and die, 155 00:12:16,836 --> 00:12:20,739 the nuclear reactions inside them speed up. 156 00:12:23,243 --> 00:12:27,703 Dr. Thaller: Giant stars burn through their nuclear fuel very, very fast -- 157 00:12:27,714 --> 00:12:29,978 sort of the, you know, the "live fast, die young." 158 00:12:29,983 --> 00:12:32,714 The more mass a star has, the hotter it burns inside, 159 00:12:32,719 --> 00:12:34,653 the faster it burns through its fuel. 160 00:12:37,390 --> 00:12:40,485 Narrator: Unlike double-star supernovas, 161 00:12:40,493 --> 00:12:42,484 really massive single stars 162 00:12:42,495 --> 00:12:45,760 create lots of elements before they explode. 163 00:12:51,805 --> 00:12:54,740 Once they turn hydrogen into helium, 164 00:12:54,741 --> 00:12:58,177 helium into carbon, and carbon into oxygen, 165 00:12:58,178 --> 00:13:01,512 they don't collapse into white-dwarf stars. 166 00:13:09,289 --> 00:13:12,691 Instead, giant stars keep on burning, 167 00:13:12,692 --> 00:13:16,720 building up layer after layer of new elements 168 00:13:16,730 --> 00:13:18,425 deep in their core. 169 00:13:22,936 --> 00:13:24,893 Woosley: Big stars don't stop 170 00:13:24,904 --> 00:13:27,896 after they've burned helium to carbon and oxygen. 171 00:13:27,907 --> 00:13:30,877 They go ahead and burn carbon to still heavier elements 172 00:13:30,877 --> 00:13:33,642 and then neon and oxygen to silicon... 173 00:13:33,647 --> 00:13:35,979 Until you get this nested Russian-doll 174 00:13:35,982 --> 00:13:38,110 spherical layer cake kind of thing. 175 00:13:39,919 --> 00:13:44,948 Narrator: These elements are the building blocks of the universe. 176 00:13:44,958 --> 00:13:49,191 But they're trapped inside the giant star. 177 00:13:49,195 --> 00:13:53,632 Somehow, they've got to get out. 178 00:13:53,633 --> 00:13:55,795 Filippenko: Studying exploding stars 179 00:13:55,802 --> 00:13:58,169 has taught us how the heavy elements of the universe 180 00:13:58,171 --> 00:13:59,502 came to be. 181 00:13:59,506 --> 00:14:03,465 They were formed by nuclear reactions inside stars. 182 00:14:03,476 --> 00:14:07,140 But if some of those stars were not to explode, 183 00:14:07,147 --> 00:14:10,777 then those elements would be locked up forever. 184 00:14:13,420 --> 00:14:16,253 Narrator: The trigger that'll release the elements 185 00:14:16,256 --> 00:14:19,556 in the single giant star is the same element 186 00:14:19,559 --> 00:14:23,393 that causes the type 1A supernova to blow up -- 187 00:14:23,396 --> 00:14:24,989 iron. 188 00:14:26,900 --> 00:14:31,394 Iron eats up all the energy of the star's nuclear fusion. 189 00:14:36,976 --> 00:14:40,310 Without the energy from nuclear fusion pushing out, 190 00:14:40,313 --> 00:14:43,977 gravity begins to crush down. 191 00:14:43,983 --> 00:14:47,044 The big star is doomed. 192 00:14:50,023 --> 00:14:53,152 The last moments of a star are really phenomenal. 193 00:14:53,159 --> 00:14:55,787 The star might last for 10 million years 194 00:14:55,795 --> 00:14:58,127 on the way to becoming a supernova, 195 00:14:58,131 --> 00:15:01,260 but the last little bit takes place very rapidly. 196 00:15:01,267 --> 00:15:05,101 Once you have an iron core and once it gets out of balance, 197 00:15:05,105 --> 00:15:07,403 it collapses in a thousandth of a second, 198 00:15:07,407 --> 00:15:09,808 a millisecond, from the size of the Earth 199 00:15:09,809 --> 00:15:12,107 down to the size of manhattan. 200 00:15:12,112 --> 00:15:15,207 It's traveling about 1/3 of the speed of light 201 00:15:15,215 --> 00:15:17,047 as it crunches down. 202 00:15:20,220 --> 00:15:22,712 Narrator: As the star becomes unstable, 203 00:15:22,722 --> 00:15:27,319 the massive power of gravity causes the core to collapse. 204 00:15:27,327 --> 00:15:30,524 This happens with such incredible power, 205 00:15:30,530 --> 00:15:34,057 even the atoms inside start to crush together. 206 00:15:42,509 --> 00:15:45,103 As it gets smaller and denser, 207 00:15:45,111 --> 00:15:48,775 the core builds up more and more energy. 208 00:15:48,782 --> 00:15:53,242 It's something with about 1 1/2 times the mass of the Sun 209 00:15:53,253 --> 00:15:55,119 that is collapsed to something 210 00:15:55,121 --> 00:15:57,351 that's only about 15 miles across. 211 00:16:00,193 --> 00:16:02,662 It's got incredible density. 212 00:16:02,662 --> 00:16:07,065 It's a thousand trillion times the density of water. 213 00:16:07,066 --> 00:16:10,058 Narrator: Now the star explodes. 214 00:16:26,152 --> 00:16:29,144 The blast rips through the star's outer layers 215 00:16:29,155 --> 00:16:30,452 and in the process, 216 00:16:30,457 --> 00:16:33,085 makes all the elements heavier than iron. 217 00:16:42,168 --> 00:16:45,297 Iron becomes cobalt. 218 00:16:45,305 --> 00:16:48,366 Cobalt becomes nickel. 219 00:16:48,374 --> 00:16:52,368 And on and on to gold, platinum, and uranium. 220 00:16:58,885 --> 00:17:00,546 The explosion is so brief, 221 00:17:00,553 --> 00:17:04,114 it only makes small amounts of these heavier elements, 222 00:17:04,123 --> 00:17:05,955 which is why they're so rare. 223 00:17:09,996 --> 00:17:13,591 The supernova blasts these new elements 224 00:17:13,600 --> 00:17:16,160 billions of miles into space. 225 00:17:16,169 --> 00:17:18,001 Lee: The only method we know, 226 00:17:18,004 --> 00:17:21,440 the only mechanism that we have found anywhere in the universe 227 00:17:21,441 --> 00:17:22,875 for creating new elements 228 00:17:22,876 --> 00:17:26,141 is in the death throes of a star called a supernova. 229 00:17:26,145 --> 00:17:29,342 Narrator: It seems incredible 230 00:17:29,349 --> 00:17:34,253 that anything could survive a supernova explosion. 231 00:17:36,890 --> 00:17:41,828 But we now know that some of the biggest bangs in the universe 232 00:17:41,828 --> 00:17:43,626 leave a corpse behind. 233 00:17:45,965 --> 00:17:48,957 And these are some of the strangest 234 00:17:48,968 --> 00:17:52,233 and most deadly objects ever discovered. 235 00:17:58,478 --> 00:18:02,244 Narrator: When a giant star goes supernova and explodes, 236 00:18:02,248 --> 00:18:04,910 it's not always the end. 237 00:18:04,918 --> 00:18:08,081 Sometimes there's a corpse. 238 00:18:15,461 --> 00:18:19,489 What kind of corpse depends on the size of the star. 239 00:18:24,804 --> 00:18:29,139 Supernovas from stars more than eight times bigger than our Sun 240 00:18:29,142 --> 00:18:31,440 leave behind a neutron star. 241 00:18:31,444 --> 00:18:35,745 And it's one of the strangest objects in the universe. 242 00:18:39,252 --> 00:18:41,016 Dr. Thaller: These things you can almost think of 243 00:18:41,020 --> 00:18:43,921 as sort of the zombies of the stellar world. 244 00:18:43,923 --> 00:18:46,392 They're very dangerous, they're very weird, 245 00:18:46,392 --> 00:18:48,383 and stars make them all the time. 246 00:18:48,394 --> 00:18:49,623 They're all around us. 247 00:18:53,733 --> 00:18:56,634 Narrator: As a giant star goes supernova, 248 00:18:56,636 --> 00:18:59,731 the core is crushed from the size of a planet 249 00:18:59,739 --> 00:19:01,229 to the size of a city. 250 00:19:04,677 --> 00:19:07,647 The pressure in the core is so intense, 251 00:19:07,647 --> 00:19:10,947 even the atoms inside it are crushed together. 252 00:19:14,487 --> 00:19:16,888 When the atoms are packed that tightly 253 00:19:16,889 --> 00:19:19,187 and there's no space left between them, 254 00:19:19,192 --> 00:19:23,823 the massive energy buildup means something's got to give. 255 00:19:32,972 --> 00:19:36,943 The core blasts off the outer layers of the star. 256 00:19:43,082 --> 00:19:48,748 And what remains is a superdense neutron star. 257 00:19:48,755 --> 00:19:52,282 Dr. Kirshner: A neutron star has the mass of a star 258 00:19:52,291 --> 00:19:54,726 crunched into a very small volume, 259 00:19:54,727 --> 00:19:58,789 and that means the density is incredibly high. 260 00:19:58,798 --> 00:20:01,267 Well, imagine taking the empire state building here behind me, 261 00:20:01,267 --> 00:20:04,760 crushing it into the size of a grain of sand. 262 00:20:04,771 --> 00:20:09,675 That's the density of the entire neutron star. 263 00:20:09,676 --> 00:20:12,077 So if you had something that dense, if you dropped it, 264 00:20:12,078 --> 00:20:13,978 it would fall straight through the Earth, 265 00:20:13,980 --> 00:20:15,675 just like a hot knife through butter. 266 00:20:18,885 --> 00:20:24,790 Narrator: A teaspoon of neutron star would weigh 100 million tons. 267 00:20:30,096 --> 00:20:33,225 Imagine something as heavy as a star 268 00:20:33,232 --> 00:20:36,293 but only the size of New York City. 269 00:20:36,302 --> 00:20:39,966 And it's spinning. 270 00:20:39,972 --> 00:20:42,771 Some of them may be born rotating 1,000 times a second. 271 00:20:42,775 --> 00:20:44,106 I mean, think about it -- 272 00:20:44,110 --> 00:20:46,306 something 1 1/2 times the mass of the Sun 273 00:20:46,312 --> 00:20:48,371 going around 1,000 times a second. 274 00:20:50,583 --> 00:20:53,883 Narrator: Some neutron stars spin so fast, 275 00:20:53,886 --> 00:20:56,856 they generate huge pulses of energy... 276 00:20:58,224 --> 00:21:00,249 ...beams of radiation 277 00:21:00,259 --> 00:21:04,992 blasting out of the star's north and south poles. 278 00:21:04,997 --> 00:21:09,559 This neutron star is called a pulsar. 279 00:21:09,569 --> 00:21:13,062 There's one of these things in the center of the Crab Nebula -- 280 00:21:13,072 --> 00:21:15,632 a place where there was a supernova explosion 281 00:21:15,641 --> 00:21:17,006 about 1,000 years ago. 282 00:21:17,009 --> 00:21:21,003 And it's one of the fastest spinning of these objects. 283 00:21:22,482 --> 00:21:26,749 Narrator: This is the actual sound a pulsar makes, 284 00:21:26,753 --> 00:21:28,915 recorded by radio telescope. 285 00:21:28,921 --> 00:21:31,822 [pulsating] 286 00:21:31,824 --> 00:21:36,853 It will flash 30 times a second for millions of years. 287 00:21:36,863 --> 00:21:39,025 [pulsating continues] 288 00:21:46,472 --> 00:21:49,066 But pulsars aren't the strangest thing 289 00:21:49,075 --> 00:21:50,907 a supernova can leave behind. 290 00:21:54,547 --> 00:21:58,745 When stars 30 times bigger than our Sun explode, 291 00:21:58,751 --> 00:22:04,053 they produce a type of neutron star called a magnetar. 292 00:22:10,897 --> 00:22:13,889 Magnetars are even weirder than pulsars 293 00:22:13,900 --> 00:22:16,801 and generate powerful magnetic fields. 294 00:22:19,071 --> 00:22:21,733 Woosley: Now, in the most extreme case, 295 00:22:21,741 --> 00:22:24,335 the magnetic field can be 10 to the 15, 296 00:22:24,343 --> 00:22:26,971 you know, a -- a hundred trillion times 297 00:22:26,979 --> 00:22:28,913 the magnetic field of the Earth. 298 00:22:32,218 --> 00:22:33,947 Narrator: That's so strong, 299 00:22:33,953 --> 00:22:36,945 it would suck the iron right out of your blood 300 00:22:36,956 --> 00:22:38,720 from thousands of miles away. 301 00:22:40,359 --> 00:22:42,521 But even pulsars and magnetars 302 00:22:42,528 --> 00:22:44,587 aren't the most dangerous objects 303 00:22:44,597 --> 00:22:47,123 a supernova can leave behind. 304 00:22:49,435 --> 00:22:53,167 When the core of a supermassive star collapses, 305 00:22:53,172 --> 00:22:55,368 it doesn't just crush atoms, 306 00:22:55,374 --> 00:22:58,969 it crushes space and time itself. 307 00:23:01,147 --> 00:23:06,711 And that is when a supernova creates a black hole. 308 00:23:16,362 --> 00:23:20,993 Narrator: When stars over 100 times heavier than our Sun explode, 309 00:23:21,000 --> 00:23:24,129 they make a supernova explosion so big... 310 00:23:25,705 --> 00:23:28,640 ...scientists call them hypernovas. 311 00:23:33,746 --> 00:23:38,582 And it was a hypernova that almost started World War Ill. 312 00:23:43,256 --> 00:23:46,521 [explosion] 313 00:23:46,525 --> 00:23:49,085 In 1963, 314 00:23:49,095 --> 00:23:50,859 the U.S. and Soviet Union 315 00:23:50,863 --> 00:23:53,560 agreed to ban testing nuclear weapons. 316 00:23:59,305 --> 00:24:02,002 To keep tabs on the Russians, 317 00:24:02,008 --> 00:24:04,409 the U.S. launched spy satellites. 318 00:24:07,413 --> 00:24:12,374 When they heard this sound coming from deep space, 319 00:24:12,385 --> 00:24:14,979 they suspected the worst. 320 00:24:14,987 --> 00:24:19,515 [pinging] 321 00:24:19,525 --> 00:24:22,586 United States government launched the Vela satellite, 322 00:24:22,595 --> 00:24:25,223 looking for nuclear detonations. 323 00:24:31,404 --> 00:24:33,839 And then, looking in outer space, 324 00:24:33,839 --> 00:24:36,501 they saw these monster explosions take place. 325 00:24:36,509 --> 00:24:39,501 And the military thought, "Oh, my God, the Russians! 326 00:24:39,512 --> 00:24:42,675 The Russians are testing secret atomic weapons in space." 327 00:24:44,216 --> 00:24:47,743 Narrator: But these weren't secret atomic-bomb tests, 328 00:24:47,753 --> 00:24:51,314 and the Russians had nothing to do with them. 329 00:24:51,324 --> 00:24:54,316 They began to look at where this radiation came from. 330 00:24:54,327 --> 00:24:57,285 It came from all over the galaxy, beyond the galaxy. 331 00:24:57,296 --> 00:25:00,698 Now, there's no way the Russians could shoot explosions 332 00:25:00,700 --> 00:25:02,930 in outer space beyond the galaxy. 333 00:25:02,935 --> 00:25:05,233 And then people began to realize 334 00:25:05,237 --> 00:25:08,707 that we were staring something new in the face. 335 00:25:08,708 --> 00:25:12,542 Narrator: They were super-powerful explosions 336 00:25:12,545 --> 00:25:16,641 of high-energy radiation called gamma-ray bursts. 337 00:25:16,649 --> 00:25:20,244 The question was, where did they come from? 338 00:25:22,288 --> 00:25:25,724 The answer was exploding hypernovas. 339 00:25:37,403 --> 00:25:40,134 During a regular supernova explosion, 340 00:25:40,139 --> 00:25:44,804 gravity crushes a star's core into a neutron star. 341 00:25:44,810 --> 00:25:47,780 But during a hypernova explosion, 342 00:25:47,780 --> 00:25:50,340 the giant star is so much bigger 343 00:25:50,349 --> 00:25:55,219 that gravity crushes the core into something much stranger... 344 00:25:58,557 --> 00:26:00,116 ...a black hole. 345 00:26:02,461 --> 00:26:04,088 And the black hole 346 00:26:04,096 --> 00:26:08,556 immediately begins to devour the dying star around it. 347 00:26:08,567 --> 00:26:10,695 Woosley: The rest of the star can't all go 348 00:26:10,703 --> 00:26:12,728 in that little bitty hole in the middle. 349 00:26:12,738 --> 00:26:15,935 It starts to swirl around, and it forms an accretion disk, 350 00:26:15,941 --> 00:26:17,739 which is feeding the black hole 351 00:26:17,743 --> 00:26:20,269 at about a million earth masses a second. 352 00:26:20,279 --> 00:26:21,576 And so, as you might imagine, 353 00:26:21,580 --> 00:26:23,412 something dramatic is gonna happen here. 354 00:26:25,885 --> 00:26:28,786 Narrator: A million earth masses a second 355 00:26:28,788 --> 00:26:32,383 is too much for the black hole to consume all at once. 356 00:26:37,029 --> 00:26:42,058 So it spits a lot of it back out at nearly the speed of light. 357 00:26:47,139 --> 00:26:50,109 This creates two beams of pure energy 358 00:26:50,109 --> 00:26:53,170 blasting their way out of the black hole. 359 00:26:55,915 --> 00:26:58,976 Takes it about eight seconds to bore through the star, 360 00:26:58,984 --> 00:27:02,477 keeping a very tight focus, and erupt from the surface. 361 00:27:02,488 --> 00:27:05,719 Now, if we're standing in the opening of this jet, 362 00:27:05,724 --> 00:27:07,419 we'll see gamma-ray bursts. 363 00:27:10,896 --> 00:27:14,230 Narrator: The gamma rays produced from the black hole 364 00:27:14,233 --> 00:27:17,760 tear through the outer layers of the star and into space. 365 00:27:17,770 --> 00:27:20,205 Gamma-ray bursts are the most violent event 366 00:27:20,206 --> 00:27:21,935 that we know of in the universe. 367 00:27:21,941 --> 00:27:25,104 A giant star blows itself to pieces and forms a black hole. 368 00:27:25,111 --> 00:27:26,636 It's incredibly spectacular. 369 00:27:26,645 --> 00:27:29,171 These gamma-ray bursts are so energetic, 370 00:27:29,181 --> 00:27:31,411 they light up the entire universe. 371 00:27:31,417 --> 00:27:33,249 Any point in the universe 372 00:27:33,252 --> 00:27:36,882 will eventually pick up this astounding radiation 373 00:27:36,889 --> 00:27:38,618 coming from a gamma-ray burst. 374 00:27:38,624 --> 00:27:42,254 That's how energetic they are. 375 00:27:42,261 --> 00:27:46,994 Narrator: They are the brightest things in the known universe. 376 00:27:46,999 --> 00:27:49,127 Woosley: To put things in perspective, 377 00:27:49,135 --> 00:27:50,660 a typical supernova explosion 378 00:27:50,669 --> 00:27:52,603 is about what the Sun will put out 379 00:27:52,605 --> 00:27:54,767 in its entire 10-billion-year lifetime. 380 00:27:54,773 --> 00:27:57,765 A gamma-ray burst viewed jet on 381 00:27:57,776 --> 00:28:03,340 is a hundred million times more luminous than a supernova. 382 00:28:03,349 --> 00:28:05,545 They're the champions for brightness, for sure. 383 00:28:11,056 --> 00:28:14,356 Narrator: They're not only bright, they're lethal. 384 00:28:17,763 --> 00:28:21,131 If a gamma-ray burst were to hit the Earth, 385 00:28:21,133 --> 00:28:24,967 it would destroy most of the atmosphere in seconds. 386 00:28:28,707 --> 00:28:31,472 A gamma-ray burster is like a rifle shot. 387 00:28:34,346 --> 00:28:37,714 [chuckling ] And if you're in the line of sight... 388 00:28:37,716 --> 00:28:39,115 Watch out. 389 00:28:39,118 --> 00:28:41,075 Once the radiation hits you, 390 00:28:41,086 --> 00:28:45,387 it'll bathe the entire surface of the Earth with nitric oxides, 391 00:28:45,391 --> 00:28:47,985 which will wipe out the ozone layer. 392 00:28:49,528 --> 00:28:53,328 Blistering radiation would hit plant life, hit algae. 393 00:28:53,332 --> 00:28:56,063 The whole food chain would collapse. 394 00:28:56,068 --> 00:28:58,264 Narrator: If the burst was close enough, 395 00:28:58,270 --> 00:29:00,762 it would cause mass extinctions. 396 00:29:00,773 --> 00:29:03,731 Dr. Thaller: Gamma-ray bursts turn out to be a lot more common 397 00:29:03,742 --> 00:29:04,834 than we thought they would be. 398 00:29:04,843 --> 00:29:06,174 So it's possible that some of these 399 00:29:06,178 --> 00:29:07,680 have even hit the Earth in the past. 400 00:29:07,680 --> 00:29:12,379 That's a pretty scary scenario. It may already have happened. 401 00:29:12,384 --> 00:29:16,355 Narrator: The question is, if it happened before, 402 00:29:16,355 --> 00:29:18,790 could it happen again? 403 00:29:22,995 --> 00:29:26,397 A gamma-ray burster is basically a supernova on steroids. 404 00:29:26,398 --> 00:29:28,867 You need a giant star to die violently. 405 00:29:28,867 --> 00:29:31,859 Now, the nearest star to us that might do that is Eta Carinae, 406 00:29:31,870 --> 00:29:33,998 and it's a spectacular nebula. 407 00:29:34,006 --> 00:29:36,771 There's all kinds of material flying off this star. 408 00:29:36,775 --> 00:29:38,243 It's very unstable. 409 00:29:38,244 --> 00:29:41,703 It may already have exploded in a gamma-ray burst. 410 00:29:41,714 --> 00:29:45,651 Narrator: But Eta Carinae may not be the only threat. 411 00:29:45,651 --> 00:29:49,815 There are other dying stars out there. 412 00:29:49,822 --> 00:29:53,190 Believe it or not, one of them is pointed in our direction. 413 00:29:53,192 --> 00:29:59,791 We are staring down the gun barrel of WR104 -- 414 00:29:59,798 --> 00:30:04,497 two dying stars that will one day undergo the gamma-ray burst. 415 00:30:04,503 --> 00:30:09,703 Not a question of if, a question of when. 416 00:30:09,708 --> 00:30:13,406 That WR104 may have our name on it. 417 00:30:13,412 --> 00:30:14,573 But the good news is 418 00:30:14,580 --> 00:30:16,810 we probably wouldn't know about it in advance. 419 00:30:16,815 --> 00:30:19,785 The shock would hit us before we had a chance to do anything. 420 00:30:19,785 --> 00:30:22,015 So there's no sense worrying about it anyway. 421 00:30:27,626 --> 00:30:29,185 Narrator: The truth is, 422 00:30:29,194 --> 00:30:32,357 we'll never know if a star is about to go hypernova 423 00:30:32,364 --> 00:30:33,627 and explode. 424 00:30:37,303 --> 00:30:41,331 Anyway, by the time we see it, it'll already be too late. 425 00:30:45,144 --> 00:30:50,844 In fact, we're already exposed to rays from dying stars 426 00:30:50,849 --> 00:30:53,546 every second of every day. 427 00:31:00,793 --> 00:31:03,490 Narrator: When giant stars explode... 428 00:31:05,397 --> 00:31:08,492 ...they make the biggest bangs in the universe. 429 00:31:14,006 --> 00:31:16,907 But what gives them so much punch? 430 00:31:20,045 --> 00:31:23,606 Until recently, no one knew. 431 00:31:23,615 --> 00:31:25,174 Kaku: Scientists, 432 00:31:25,184 --> 00:31:28,279 when they tried to simulate a supernova explosion 433 00:31:28,287 --> 00:31:31,689 in a computer, had a problem. 434 00:31:31,690 --> 00:31:35,558 They simply could not get enough energy out of the dying star 435 00:31:35,561 --> 00:31:37,051 to create a supernova. 436 00:31:37,062 --> 00:31:39,292 This was a calamity in astronomy. 437 00:31:47,673 --> 00:31:51,974 Narrator: Computer models couldn't make the simulated stars blow up. 438 00:31:57,249 --> 00:32:01,049 To blow up a star, you need a lot of energy. 439 00:32:03,021 --> 00:32:07,390 The trouble was, astronomers couldn't find it. 440 00:32:07,393 --> 00:32:10,488 Filippenko: The visible radiation that you see 441 00:32:10,496 --> 00:32:14,626 is a tiny fraction of the total energy emitted. 442 00:32:14,633 --> 00:32:18,570 Even the energy of motion of the expanding gases 443 00:32:18,570 --> 00:32:21,039 is only 1% of the total energy. 444 00:32:21,039 --> 00:32:24,976 Narrator: Where was the missing 99% of the energy 445 00:32:24,977 --> 00:32:26,604 from the explosion? 446 00:32:26,612 --> 00:32:28,046 The only way scientists 447 00:32:28,046 --> 00:32:31,209 could get their simulations to match the real thing 448 00:32:31,216 --> 00:32:36,017 was to add in a mysterious particle called the neutrino. 449 00:32:36,021 --> 00:32:40,151 Without it, their numbers didn't add up. 450 00:32:40,159 --> 00:32:43,754 That was the easy bit. 451 00:32:43,762 --> 00:32:45,321 Their next step 452 00:32:45,330 --> 00:32:49,995 was to prove supernovas really do produce neutrinos. 453 00:32:53,939 --> 00:32:57,500 In 1987, they got lucky. 454 00:33:01,413 --> 00:33:03,848 168,000 years ago, 455 00:33:03,849 --> 00:33:07,080 a supernova exploded in a nearby galaxy 456 00:33:07,085 --> 00:33:09,884 called the Large Magellanic Cloud. 457 00:33:12,424 --> 00:33:15,621 When scientists saw the light from the blast, 458 00:33:15,627 --> 00:33:19,188 they called it supernova 1987. 459 00:33:22,134 --> 00:33:24,398 Supernova 1987A is really important 460 00:33:24,403 --> 00:33:27,634 in the study of supernovae because it's the first one 461 00:33:27,639 --> 00:33:30,131 since the invention of the telescope. 462 00:33:30,142 --> 00:33:32,770 It's the one that we've been able to study 463 00:33:32,778 --> 00:33:35,577 right from the time of explosion through now, 464 00:33:35,581 --> 00:33:38,482 using all the instruments that we've developed. 465 00:33:38,484 --> 00:33:40,680 Narrator: One of those instruments 466 00:33:40,686 --> 00:33:45,146 was a giant neutrino detector buried deep underground. 467 00:33:45,157 --> 00:33:48,286 And bingo -- we saw a burst of radiation 468 00:33:48,293 --> 00:33:50,352 go through our neutrino detectors, 469 00:33:50,362 --> 00:33:53,957 and we said, "Aha! That's the proof!" 470 00:33:53,966 --> 00:33:57,368 Dr. Kirshner: The discovery of neutrinos from supernova 1987A 471 00:33:57,369 --> 00:33:58,700 was a tremendous thing 472 00:33:58,704 --> 00:34:01,401 because for many years people had been saying, 473 00:34:01,406 --> 00:34:03,704 "That's where 99% of the energy goes," 474 00:34:03,709 --> 00:34:05,302 but no one had ever seen it. 475 00:34:05,310 --> 00:34:07,301 This is now the smoking gun 476 00:34:07,312 --> 00:34:10,145 that we can now prove that neutrinos 477 00:34:10,148 --> 00:34:12,446 carry the energy of a supernova, 478 00:34:12,451 --> 00:34:14,852 and we detected it right on the Earth 479 00:34:14,853 --> 00:34:18,153 as we saw a supernova in outer space. 480 00:34:20,092 --> 00:34:25,496 Narrator: Neutrinos are trillions of times smaller than atoms. 481 00:34:28,734 --> 00:34:32,830 They're created by all sorts of nuclear reactions... 482 00:34:34,273 --> 00:34:39,109 ...from nuclear power plants and bombs to exploding stars. 483 00:34:40,779 --> 00:34:46,013 If you had "neutrino-vision," you'd see them everywhere. 484 00:34:50,923 --> 00:34:54,291 Kaku: Neutrinos are ghostlike particles. 485 00:34:55,994 --> 00:34:59,259 Literally, trillions of them are going through my body 486 00:34:59,264 --> 00:35:00,561 even as we speak. 487 00:35:00,566 --> 00:35:03,627 In fact, neutrinos come from the bottom of the floor, 488 00:35:03,635 --> 00:35:05,160 right through the Earth, 489 00:35:05,170 --> 00:35:07,605 and even hit me right through my legs. 490 00:35:07,606 --> 00:35:11,236 Narrator: Pretty strange. 491 00:35:11,243 --> 00:35:16,807 Imagine so many tiny particles zooming through our bodies. 492 00:35:16,815 --> 00:35:20,877 But where do they get all their energy? 493 00:35:23,622 --> 00:35:28,458 When a core crushes down just before a supernova explosion, 494 00:35:28,460 --> 00:35:31,452 the atoms inside it are broken up. 495 00:35:35,133 --> 00:35:37,033 The core gets so hot, 496 00:35:37,035 --> 00:35:41,370 it turns this atomic debris into blazing neutrinos. 497 00:35:45,811 --> 00:35:50,271 Woosley: We think that supernovae produce a stupendous sum of neutrinos 498 00:35:50,282 --> 00:35:53,513 when the core collapses to a neutron star. 499 00:35:53,518 --> 00:35:54,849 For about 10 seconds, 500 00:35:54,853 --> 00:35:57,550 that core shines with a neutrino luminosity 501 00:35:57,556 --> 00:36:00,685 that is greater than all of the energy being produced 502 00:36:00,692 --> 00:36:03,320 in the rest of the universe at that time. 503 00:36:03,328 --> 00:36:08,061 Narrator: In other words, it's really bright. 504 00:36:08,066 --> 00:36:12,037 But gravity can't hold these neutrinos in the core. 505 00:36:14,206 --> 00:36:18,040 They burst free in a blinding flash of light 506 00:36:18,043 --> 00:36:20,569 that rips the dying star apart. 507 00:36:26,184 --> 00:36:27,709 The discovery of neutrinos 508 00:36:27,719 --> 00:36:30,814 transformed the science of supernovas. 509 00:36:32,524 --> 00:36:35,585 But supernovas were about to reveal 510 00:36:35,594 --> 00:36:38,620 the most mysterious force of all -- 511 00:36:38,630 --> 00:36:42,533 one that's changing the destiny of the universe. 512 00:36:45,570 --> 00:36:48,801 [explosion] 513 00:36:50,809 --> 00:36:53,278 Narrator: Supernova explosions are so bright, 514 00:36:53,278 --> 00:36:56,407 we can see them across the entire universe. 515 00:36:58,684 --> 00:37:00,709 This has helped astronomers 516 00:37:00,719 --> 00:37:04,553 unlock one of the deepest mysteries of the cosmos. 517 00:37:08,794 --> 00:37:11,024 The universe came to life 518 00:37:11,029 --> 00:37:14,363 in the Big Bang 14 billion years ago. 519 00:37:18,470 --> 00:37:23,772 It expanded from a tiny ball of energy smaller than an atom 520 00:37:23,775 --> 00:37:29,009 to a universe billions and billions of light-years across. 521 00:37:29,014 --> 00:37:32,006 And it's still expanding. 522 00:37:33,585 --> 00:37:35,679 I've often wondered how far future people 523 00:37:35,687 --> 00:37:37,655 will even know the Big Bang happened, 524 00:37:37,656 --> 00:37:39,590 because we know the Big Bang happened 525 00:37:39,591 --> 00:37:41,923 from watching all the galaxies fly away from us. 526 00:37:44,162 --> 00:37:48,224 Someday, the galaxies will be so far away from each other, 527 00:37:48,233 --> 00:37:52,033 it will be impossible to see anything else in the sky. 528 00:37:52,037 --> 00:37:54,131 Narrator: Scientists used to think 529 00:37:54,139 --> 00:37:56,938 the expanding universe was slowing down, 530 00:37:56,942 --> 00:37:59,707 but there was no way to prove it... 531 00:38:02,781 --> 00:38:08,185 ...until they found double-star supernovas, type 1AS. 532 00:38:10,655 --> 00:38:14,649 They always explode when the white-dwarf star 533 00:38:14,659 --> 00:38:18,653 reaches exactly 1.4 times the mass of our Sun. 534 00:38:24,035 --> 00:38:26,094 And their explosions 535 00:38:26,104 --> 00:38:30,735 always release exactly the same amount of light. 536 00:38:32,310 --> 00:38:37,214 They are the perfect markers to measure distance in space. 537 00:38:38,817 --> 00:38:40,512 Krauss: Type 1A supernovae, 538 00:38:40,519 --> 00:38:43,682 when we know how bright they are and how bright they look, 539 00:38:43,688 --> 00:38:45,122 we can tell the distance, 540 00:38:45,123 --> 00:38:47,114 'cause the farther away they are, 541 00:38:47,125 --> 00:38:49,651 the less bright they'll look in the telescope. 542 00:38:51,763 --> 00:38:54,926 And that has allowed us to accurately measure distances 543 00:38:54,933 --> 00:38:56,526 not just to nearby galaxies 544 00:38:56,535 --> 00:38:59,493 but to galaxies at the other end of the visible universe -- 545 00:38:59,504 --> 00:39:01,905 billions of light-years. 546 00:39:01,907 --> 00:39:04,672 And that has allowed us to make incredible discoveries. 547 00:39:07,045 --> 00:39:09,810 Narrator: Astronomers thought they had found a way 548 00:39:09,815 --> 00:39:14,082 to prove the expansion rate of the universe was slowing down. 549 00:39:14,085 --> 00:39:16,952 What they got was a big surprise. 550 00:39:18,523 --> 00:39:20,025 Krauss: In 1998, 551 00:39:20,025 --> 00:39:24,019 astronomers made a remarkable and unexpected discovery. 552 00:39:24,029 --> 00:39:25,895 It was recognized that the universe, 553 00:39:25,897 --> 00:39:27,262 which should be slowing down, 554 00:39:27,265 --> 00:39:29,324 'cause gravity, after all, is attractive, 555 00:39:29,334 --> 00:39:31,769 and the mass of objects should cause the expansion 556 00:39:31,770 --> 00:39:33,169 of the universe to slow down. 557 00:39:33,171 --> 00:39:36,607 But the expansion is speeding up. 558 00:39:36,608 --> 00:39:38,406 It's accelerating. 559 00:39:41,112 --> 00:39:44,605 Narrator: The constant light from type 1A supernovas 560 00:39:44,616 --> 00:39:47,449 completely changed the way astronomers 561 00:39:47,452 --> 00:39:48,954 understand the universe. 562 00:39:48,954 --> 00:39:51,889 Kaku: Every science textbook on the Earth 563 00:39:51,890 --> 00:39:55,520 says that the universe is expanding and slowing down. 564 00:39:55,527 --> 00:39:57,052 Wrong. 565 00:39:57,062 --> 00:40:00,293 We now have to rewrite all the science textbooks 566 00:40:00,298 --> 00:40:01,629 on the planet Earth. 567 00:40:06,972 --> 00:40:09,134 Narrator: But astronomers still didn't know 568 00:40:09,140 --> 00:40:12,838 why the universe is expanding faster and faster. 569 00:40:14,145 --> 00:40:18,844 They began to think it's some kind of unknown energy. 570 00:40:21,086 --> 00:40:22,986 They called it "dark energy," 571 00:40:22,988 --> 00:40:25,082 but it's difficult to prove 572 00:40:25,090 --> 00:40:29,755 because it can't be seen or touched or detected. 573 00:40:29,761 --> 00:40:33,561 Filippenko: We really don't have a very good clue 574 00:40:33,565 --> 00:40:37,468 as to the physical nature and origin of dark energy. 575 00:40:39,371 --> 00:40:41,203 It's perhaps the number-one 576 00:40:41,206 --> 00:40:43,607 observationally motivated problem 577 00:40:43,608 --> 00:40:47,579 in all of physics right now -- the nature of the dark energy. 578 00:40:55,820 --> 00:40:58,687 Narrator: From dark energy to black holes, 579 00:40:58,690 --> 00:41:00,215 supernovas have revealed 580 00:41:00,225 --> 00:41:03,661 some of the most profound mysteries of the universe. 581 00:41:08,199 --> 00:41:09,928 These exploding stars 582 00:41:09,935 --> 00:41:12,768 give us the building blocks of the universe 583 00:41:12,771 --> 00:41:15,729 and show us how it's all made. 584 00:41:17,776 --> 00:41:19,642 It's hard to imagine, 585 00:41:19,644 --> 00:41:22,136 but the atoms in our bodies today 586 00:41:22,147 --> 00:41:26,573 were made by a supernova billions of years ago. 587 00:41:30,689 --> 00:41:32,885 The Bible say, "From dust to dust." 588 00:41:32,891 --> 00:41:36,725 Astronomers say, "From stardust to stardust." 589 00:41:36,728 --> 00:41:42,326 So supernovae are the key link in this cycle of life. 590 00:41:42,334 --> 00:41:44,996 Dr. Thaller: People think of space as being something 591 00:41:45,003 --> 00:41:46,698 very distant and very remote. 592 00:41:46,705 --> 00:41:49,868 It's light-years away, hugely distant from us. 593 00:41:49,874 --> 00:41:51,569 That's completely wrong. 594 00:41:51,576 --> 00:41:53,374 Supernovae are right here. 595 00:41:53,378 --> 00:41:54,971 We are their children. 596 00:41:54,980 --> 00:41:57,847 They made us, literally put us together. 597 00:41:57,849 --> 00:41:59,112 We are star stuff. 598 00:41:59,117 --> 00:42:02,610 Without the supernovas, we could not exist. 599 00:42:02,620 --> 00:42:05,851 So when we walk around at night and we look up at the night sky 600 00:42:05,857 --> 00:42:09,521 and we see the stars and we feel somehow a part of them... 601 00:42:09,527 --> 00:42:11,052 [ (109 barks ] 602 00:42:11,062 --> 00:42:13,087 ...the truth is, we are. 603 00:42:13,098 --> 00:42:15,089 They are our parents. 604 00:42:23,208 --> 00:42:29,045 Narrator: Some scientists believe the age of supernovas could be ending. 605 00:42:29,047 --> 00:42:32,608 Smaller, slower-burning stars, like our Sun, 606 00:42:32,617 --> 00:42:34,483 will become more common 607 00:42:34,486 --> 00:42:37,251 and giant stars become more rare. 608 00:42:42,861 --> 00:42:46,092 Supernovas have given us galaxies, 609 00:42:46,097 --> 00:42:50,000 solar systems, stars, and planets. 610 00:42:50,001 --> 00:42:53,835 They made us and everything we see. 611 00:42:56,074 --> 00:42:59,044 They are where destruction and creation meet. 612 00:42:59,044 --> 00:43:00,910 The destiny of the universe 613 00:43:00,912 --> 00:43:05,281 lies in the ashes of dying stars.