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Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:06,800 --> 00:00:09,870 Neutron stars. 2 00:00:09,870 --> 00:00:11,940 Super heavy, super dense. 3 00:00:11,940 --> 00:00:13,340 Extreme. 4 00:00:13,340 --> 00:00:17,580 Gravitational, magnetic, hot. 5 00:00:17,580 --> 00:00:19,250 Scary. 6 00:00:19,250 --> 00:00:22,220 They destroy planets. 7 00:00:22,220 --> 00:00:24,990 They can even destroy stars. 8 00:00:24,990 --> 00:00:27,390 A cosmic conundrum. 9 00:00:27,390 --> 00:00:30,290 They're very, very massive, 10 00:00:30,290 --> 00:00:32,230 but they're also really, really small. 11 00:00:32,230 --> 00:00:34,560 Tiny cosmic super powers 12 00:00:34,570 --> 00:00:39,840 long overshadowed by black holes... Until now. 13 00:00:39,840 --> 00:00:41,940 Neutron stars have been thrust very much 14 00:00:41,940 --> 00:00:44,410 to the forefront of modern astrophysics. 15 00:00:44,410 --> 00:00:47,780 The world's astronomers know that something is happening. 16 00:00:47,780 --> 00:00:50,780 Something's up, it's new, and it's different. 17 00:00:50,780 --> 00:00:54,850 Neutron stars are the most interesting 18 00:00:54,850 --> 00:00:58,220 astrophysical object in the universe. 19 00:00:58,220 --> 00:01:00,890 Now firmly in the limelight, 20 00:01:00,890 --> 00:01:06,030 neutron stars, creators of our most precious elements 21 00:01:06,030 --> 00:01:07,830 and life itself. 22 00:01:07,830 --> 00:01:10,830 Captions by vitac... www.vitac.com 23 00:01:10,830 --> 00:01:13,870 captions paid for by discovery communications 24 00:01:26,180 --> 00:01:29,920 130 million light years form earth, 25 00:01:29,920 --> 00:01:34,860 a galaxy called "NGC-4993." 26 00:01:34,860 --> 00:01:39,630 Two dead stars trapped in a rapidly diminishing spiral. 27 00:01:46,200 --> 00:01:49,600 It's like listening to the ringing of the cosmos itself. 28 00:01:49,610 --> 00:01:51,710 The sound of that collision, if you will, 29 00:01:51,710 --> 00:01:56,240 imprinted on the fabric of space and time itself. 30 00:01:56,250 --> 00:02:01,880 Livingston, Louisiana, the advanced LiGO observatory. 31 00:02:01,890 --> 00:02:04,890 Its mission... To detect gravitational waves 32 00:02:04,890 --> 00:02:06,520 generated in space. 33 00:02:08,790 --> 00:02:12,290 A gravitational wave is a distortion of space time 34 00:02:12,300 --> 00:02:13,700 that's caused by, usually, 35 00:02:13,700 --> 00:02:17,700 some kind of very traumatic gravitational event. 36 00:02:17,700 --> 00:02:20,400 Events such as a supernova, 37 00:02:20,400 --> 00:02:23,940 or the collision of black holes, or massive stars. 38 00:02:25,780 --> 00:02:31,150 2015... LiGO makes history by detecting gravitational waves 39 00:02:31,150 --> 00:02:32,710 for the first time, 40 00:02:32,720 --> 00:02:37,050 100 years after Einstein's prediction. 41 00:02:37,050 --> 00:02:42,160 It's the signature of the crash of black holes. 42 00:02:42,160 --> 00:02:44,230 It's almost like listening to the sound 43 00:02:44,230 --> 00:02:47,400 of a distant car crash that you didn't witness. 44 00:02:47,400 --> 00:02:49,260 But you're so clever, 45 00:02:49,270 --> 00:02:52,530 and the sound of this car crash is such a unique signature, 46 00:02:52,540 --> 00:02:55,270 that you are able to use your computers to model 47 00:02:55,270 --> 00:03:00,240 exactly the type of cars that must have collided together. 48 00:03:00,240 --> 00:03:06,380 In 2017, LiGO picks up a different kind of signal. 49 00:03:06,380 --> 00:03:09,020 The unfolding of the August 2017 event 50 00:03:09,020 --> 00:03:11,690 was nothing short of extraordinary. 51 00:03:11,690 --> 00:03:15,190 So, the signal comes in, and the signal is strange. 52 00:03:15,190 --> 00:03:18,090 It has a long-lasting signal. 53 00:03:18,100 --> 00:03:19,630 It's over 100 seconds. 54 00:03:19,630 --> 00:03:22,530 Less than two seconds later, a gamma-ray telescope 55 00:03:22,530 --> 00:03:25,100 detected a flash of gamma rays 56 00:03:25,100 --> 00:03:27,540 from that same part of the sky. 57 00:03:27,540 --> 00:03:30,670 And very quickly, the world's astronomers 58 00:03:30,670 --> 00:03:32,610 know that something is happening. 59 00:03:32,610 --> 00:03:35,640 Something's up, it's new, and it's different. 60 00:03:38,720 --> 00:03:42,080 This combination of a long gravitational wave signal 61 00:03:42,090 --> 00:03:46,290 and a blaze of gamma rays... 62 00:03:46,290 --> 00:03:48,790 Acts as a beacon for astronomers. 63 00:03:51,460 --> 00:03:53,260 When they saw this event, 64 00:03:53,260 --> 00:03:55,400 they sent out a worldwide alert 65 00:03:55,400 --> 00:03:57,630 to astronomers across the globe, saying, 66 00:03:57,630 --> 00:04:00,640 "hey, we saw something interesting, 67 00:04:00,640 --> 00:04:03,410 and it came from a particular patch of sky. 68 00:04:03,410 --> 00:04:05,470 Then, all the chatter started 69 00:04:05,480 --> 00:04:07,540 amongst the astronomical community, 70 00:04:07,540 --> 00:04:09,850 and everyone starting pointing their telescopes 71 00:04:09,850 --> 00:04:12,910 at this one part of the sky. 72 00:04:12,920 --> 00:04:15,480 Within hours, thousands of astronomers 73 00:04:15,490 --> 00:04:18,620 and physicists across the globe are frantically 74 00:04:18,620 --> 00:04:22,790 collecting data on this mysterious event. 75 00:04:22,790 --> 00:04:24,960 There is not just the gravitational waves, 76 00:04:24,960 --> 00:04:26,660 there is not just the gamma rays. 77 00:04:26,660 --> 00:04:28,960 There's a visible light, there's infrared light, 78 00:04:28,970 --> 00:04:30,670 there's ultraviolet light. 79 00:04:30,670 --> 00:04:33,970 And all these signals together tell us a story. 80 00:04:33,970 --> 00:04:36,140 And this was the very first time 81 00:04:36,140 --> 00:04:38,810 we've seen these two multiple messengers at once... 82 00:04:38,810 --> 00:04:41,380 Gravitational waves and regular light. 83 00:04:41,380 --> 00:04:44,380 So, that was a groundbreaking moment for astronomy. 84 00:04:48,050 --> 00:04:49,750 Scientists realize 85 00:04:49,750 --> 00:04:52,850 this isn't another black-hole collision. 86 00:04:52,860 --> 00:04:55,790 This is something different. 87 00:04:55,790 --> 00:04:58,360 When you see an explosion in the universe, 88 00:04:58,360 --> 00:05:00,760 there aren't exactly a lot of candidates. 89 00:05:00,760 --> 00:05:04,030 There's not a lot of things in the universe that blow up. 90 00:05:06,240 --> 00:05:10,010 But the length of the signal is the smoking gun. 91 00:05:10,010 --> 00:05:13,210 The collision of two black holes was quick. 92 00:05:13,210 --> 00:05:19,180 This one was the longer, slower, death end-spiral 93 00:05:19,180 --> 00:05:21,350 of two neutron stars. 94 00:05:21,350 --> 00:05:25,190 Spiraling in, closer and closer, speeding up. 95 00:05:25,190 --> 00:05:26,860 And then, when they finally collide, 96 00:05:26,860 --> 00:05:29,360 when they finally touch, releasing a tremendous 97 00:05:29,360 --> 00:05:32,290 amount of energy into the surrounding system. 98 00:05:34,560 --> 00:05:37,470 The collision throws up huge clouds of matter, 99 00:05:37,470 --> 00:05:40,740 which may have slowed down the light very slightly. 100 00:05:40,740 --> 00:05:43,000 The light and gravitational waves 101 00:05:43,010 --> 00:05:46,340 travel for 130 million years, 102 00:05:46,340 --> 00:05:50,780 arriving at earth almost simultaneously. 103 00:05:50,780 --> 00:05:55,320 It's the first time astronomers see neutron stars collide. 104 00:05:55,320 --> 00:05:57,920 They call it a "kilonova." 105 00:05:57,920 --> 00:06:00,490 And this spectacular cosmic event 106 00:06:00,490 --> 00:06:03,220 doesn't just release energy. 107 00:06:03,230 --> 00:06:05,490 The aftermath of this neutron-star collision, 108 00:06:05,500 --> 00:06:08,560 this kilonova, created a tremendous amount of debris, 109 00:06:08,570 --> 00:06:10,570 which blasted out into space. 110 00:06:10,570 --> 00:06:12,570 And this may finally have provided us 111 00:06:12,570 --> 00:06:15,170 the evidence of where some very special 112 00:06:15,170 --> 00:06:17,440 heavy elements are created. 113 00:06:17,440 --> 00:06:22,380 Through the destruction of a neutron star comes the seeds 114 00:06:22,380 --> 00:06:25,480 for the essential ingredients of life itself. 115 00:06:25,480 --> 00:06:29,080 We breathe oxygen molecules... O2. 116 00:06:29,090 --> 00:06:31,220 Water is hydrogen and oxygen. 117 00:06:31,220 --> 00:06:34,690 Most of our body is made up of carbon compounds 118 00:06:34,690 --> 00:06:36,590 that include nitrogen, phosphorus. 119 00:06:36,590 --> 00:06:39,260 One of the big questions in science 120 00:06:39,260 --> 00:06:41,760 over the history of humanity has been, 121 00:06:41,770 --> 00:06:44,600 "what are the origins of these elements?" 122 00:06:44,600 --> 00:06:48,800 And it turns out that neutron stars play a critical role 123 00:06:48,810 --> 00:06:51,410 in creating many of the heavy elements. 124 00:06:54,640 --> 00:07:00,220 Most of the elements on earth are made in stars. 125 00:07:00,220 --> 00:07:02,850 But how the heaviest elements are made 126 00:07:02,850 --> 00:07:06,590 has been one of science's longest-running mysteries. 127 00:07:08,560 --> 00:07:10,360 For a long time, we knew there was a problem 128 00:07:10,360 --> 00:07:12,030 with making these heavier atoms... 129 00:07:12,030 --> 00:07:15,400 Things like gold and platinum, all the way out towards uranium. 130 00:07:15,400 --> 00:07:17,100 And really, the most energetic thing we had 131 00:07:17,100 --> 00:07:19,570 in the universe was supernova explosions. 132 00:07:19,570 --> 00:07:22,640 So, they had to be created somehow in supernovas. 133 00:07:22,640 --> 00:07:25,670 But when scientists ran computer simulations, 134 00:07:25,680 --> 00:07:30,410 virtual supernovas failed to forge these oversized atoms. 135 00:07:33,620 --> 00:07:37,550 In 2016, astronomer Edo Berger explained 136 00:07:37,550 --> 00:07:40,190 a potential solution to the mystery. 137 00:07:43,890 --> 00:07:45,690 If you open any one of these books, 138 00:07:45,700 --> 00:07:48,730 and flip to the page that tells you where gold came from, 139 00:07:48,730 --> 00:07:51,500 it will tell you that gold came from supernova explosions. 140 00:07:57,540 --> 00:08:01,580 But it was becoming clear that the textbooks were out of date. 141 00:08:06,720 --> 00:08:09,280 To form heavy elements requires a lot of neutrons, 142 00:08:09,290 --> 00:08:11,690 and so, another possible theory was that 143 00:08:11,690 --> 00:08:14,460 the heaviest elements were produced in the mergers 144 00:08:14,460 --> 00:08:17,730 of two neutron stars in a binary system. 145 00:08:17,730 --> 00:08:20,300 But at the time, no one had actually seen 146 00:08:20,300 --> 00:08:22,330 a neutron-star collision. 147 00:08:22,330 --> 00:08:24,600 It was difficult to convince the community 148 00:08:24,600 --> 00:08:26,670 that this was a potential channel 149 00:08:26,670 --> 00:08:28,970 for the production of heavy elements. 150 00:08:28,970 --> 00:08:31,510 The proof is to actually see this process 151 00:08:31,510 --> 00:08:32,770 happening in the universe. 152 00:08:34,740 --> 00:08:36,710 The 2017 kilonova 153 00:08:36,710 --> 00:08:39,280 provides the perfect opportunity. 154 00:08:39,280 --> 00:08:43,150 It generates thousands of hours of data. 155 00:08:43,150 --> 00:08:45,690 Scientists notice a pattern... 156 00:08:45,690 --> 00:08:50,960 Subtle changes in the color of the kilonova remnants. 157 00:08:50,960 --> 00:08:53,760 In space, when you have an event that is very bright, 158 00:08:53,760 --> 00:08:55,300 it emits a certain amount of light, 159 00:08:55,300 --> 00:08:57,100 and it emits it at certain wavelengths... 160 00:08:57,100 --> 00:08:59,530 What we think of as colors. 161 00:08:59,540 --> 00:09:02,540 Different colors in a pyrotechnics display 162 00:09:02,540 --> 00:09:06,110 indicate the use of different chemicals in fireworks. 163 00:09:06,110 --> 00:09:09,580 In the same way, scientists can uncover the elements 164 00:09:09,580 --> 00:09:14,520 in the kilonova by the colors in the explosion. 165 00:09:14,520 --> 00:09:18,390 As the kilonova turns red, they realize it's the result 166 00:09:18,390 --> 00:09:20,520 of newly-created heavy elements 167 00:09:20,520 --> 00:09:23,630 starting to absorb blue light. 168 00:09:23,630 --> 00:09:25,990 As we watched this remnant change... 169 00:09:26,000 --> 00:09:29,100 The explosion change in color, expand and cool... 170 00:09:29,100 --> 00:09:32,070 We could estimate what sort of elements were being produced. 171 00:09:34,370 --> 00:09:36,470 The light from the debris shifts 172 00:09:36,470 --> 00:09:40,280 from blue and Violet to red and infrared. 173 00:09:40,280 --> 00:09:43,040 The color change provides clues 174 00:09:43,050 --> 00:09:46,510 about the presence of certain heavy metals. 175 00:09:54,490 --> 00:09:57,430 Well, this neutron-star collision, this kilonova, 176 00:09:57,430 --> 00:10:00,500 produced brightness and a color spectrum 177 00:10:00,500 --> 00:10:03,930 that are consistent with models of predictions 178 00:10:03,930 --> 00:10:06,100 that produce gold and platinum. 179 00:10:08,540 --> 00:10:11,440 This model is called "The R-process," 180 00:10:11,440 --> 00:10:14,410 short for "rapid neutron capture." 181 00:10:14,410 --> 00:10:16,780 That is a bit of a complicated term 182 00:10:16,780 --> 00:10:20,250 that describes how we make atoms heavier than iron. 183 00:10:20,250 --> 00:10:22,580 You need a really neutron-rich environment. 184 00:10:22,590 --> 00:10:25,390 And as you might imagine, a neutron-star collision 185 00:10:25,390 --> 00:10:27,960 is a very neutron-rich environment. 186 00:10:27,960 --> 00:10:29,720 If these models are correct... 187 00:10:29,730 --> 00:10:31,930 And this blows me away... 188 00:10:31,930 --> 00:10:33,830 This collision, this kilonova, 189 00:10:33,830 --> 00:10:38,030 produced several dozen times the mass of the Earth 190 00:10:38,030 --> 00:10:40,070 in just gold. 191 00:10:46,710 --> 00:10:50,110 The 2017 kilonova not only reveals 192 00:10:50,110 --> 00:10:52,380 the origin of key elements, 193 00:10:52,380 --> 00:10:56,080 it sheds light on the neutron star's interior... 194 00:10:56,090 --> 00:10:59,190 The strongest material in the universe 195 00:10:59,190 --> 00:11:01,020 creating a magnetic field 196 00:11:01,020 --> 00:11:04,790 a trillion times greater than that of earth. 197 00:11:23,200 --> 00:11:28,470 Two neutron stars caught in a death spiral. 198 00:11:28,470 --> 00:11:32,540 This massive kilonova explosion not only sheds light 199 00:11:32,540 --> 00:11:34,580 on the creation of heavy elements, 200 00:11:34,580 --> 00:11:36,910 such as gold and platinum, 201 00:11:36,920 --> 00:11:40,150 it also provides scientists with a unique insight 202 00:11:40,150 --> 00:11:44,450 into one of the most mysterious objects in the universe. 203 00:11:44,460 --> 00:11:47,520 Trying to imagine what a neutron star is really like 204 00:11:47,530 --> 00:11:49,330 really challenges our imagination. 205 00:11:49,330 --> 00:11:51,590 It also challenges our theoretical physics. 206 00:11:51,600 --> 00:11:54,100 We have to go to our computer models, our mathematics, 207 00:11:54,100 --> 00:11:58,070 to have some estimate of what this might be like. 208 00:11:58,070 --> 00:12:00,600 Now, scientists don't have to rely 209 00:12:00,610 --> 00:12:02,170 on their imaginations. 210 00:12:03,510 --> 00:12:07,210 They can use hard data from the kilonova 211 00:12:07,210 --> 00:12:10,380 to work out what makes neutron stars tick. 212 00:12:14,820 --> 00:12:16,890 There's so much information we got from observing 213 00:12:16,890 --> 00:12:20,360 that one single event, that one colliding neutron star pair. 214 00:12:20,360 --> 00:12:22,860 Now, for the first time, we have an accurate estimate 215 00:12:22,860 --> 00:12:25,290 of the mass of a neutron star, and the diameter. 216 00:12:25,300 --> 00:12:27,000 We can finally begin to piece together 217 00:12:27,000 --> 00:12:30,570 how neutron stars really work. 218 00:12:30,570 --> 00:12:34,770 They calculate the diameter is just 12.4 miles, 219 00:12:34,770 --> 00:12:39,510 1 mile less than the length of Manhattan. 220 00:12:39,510 --> 00:12:41,980 Nailing down any physical characteristic 221 00:12:41,980 --> 00:12:43,310 is really important. 222 00:12:43,310 --> 00:12:44,610 And if there's gonna be one, 223 00:12:44,620 --> 00:12:47,250 the radius is a big one, because from there, 224 00:12:47,250 --> 00:12:49,020 if you know the mass, you can get the density. 225 00:12:49,020 --> 00:12:50,650 And if you know the overall density, 226 00:12:50,660 --> 00:12:52,390 you can start to figure out what the layering 227 00:12:52,390 --> 00:12:54,320 inside of a neutron star is like. 228 00:12:58,300 --> 00:13:01,860 For physicists, the interior of a neutron star 229 00:13:01,870 --> 00:13:06,300 is one of the most intriguing places in the universe. 230 00:13:06,300 --> 00:13:07,870 You have to realize that the conditions 231 00:13:07,870 --> 00:13:09,970 inside a neutron star are very, very different 232 00:13:09,970 --> 00:13:12,070 than the conditions that exist here on earth. 233 00:13:12,080 --> 00:13:14,140 We're talking about material that's so dense 234 00:13:14,150 --> 00:13:17,450 that even the nuclei of atoms can't hold together. 235 00:13:17,450 --> 00:13:19,620 With a neutron star, you're taking something 236 00:13:19,620 --> 00:13:22,020 that weighs more than the sun, 237 00:13:22,020 --> 00:13:25,720 and compressing it down to be smaller than a city. 238 00:13:25,720 --> 00:13:28,520 It's so dense that, if you tried to put it on the ground, 239 00:13:28,530 --> 00:13:30,490 it would fall right through the Earth. 240 00:13:32,460 --> 00:13:35,460 High density means high gravity... 241 00:13:35,470 --> 00:13:40,270 Gravity 200 billion times greater than on earth. 242 00:13:40,270 --> 00:13:41,870 Imagine climbing up on a table on the surface 243 00:13:41,870 --> 00:13:43,740 of a neutron star and jumping off. 244 00:13:43,740 --> 00:13:45,940 You're gonna just get flattened instantly, 245 00:13:45,940 --> 00:13:48,510 and just spread out on that surface. 246 00:13:48,510 --> 00:13:52,920 So, don't even think about trying to do push-ups. 247 00:13:52,920 --> 00:13:54,720 Added to the intense gravity 248 00:13:54,720 --> 00:13:57,420 are hugely powerful magnetic fields, 249 00:13:57,420 --> 00:13:59,520 awesome X-ray radiation, 250 00:13:59,520 --> 00:14:03,290 electric fields 30 million times more powerful 251 00:14:03,290 --> 00:14:05,290 than lightning bolts, 252 00:14:05,300 --> 00:14:09,370 and blizzards of high-energy particles. 253 00:14:09,370 --> 00:14:13,400 This isn't a good neighborhood for a space traveler. 254 00:14:16,370 --> 00:14:19,280 If you were to find yourself in the vicinity 255 00:14:19,280 --> 00:14:22,910 of a neutron star, it's gonna be bad news. 256 00:14:22,910 --> 00:14:24,910 First, you would be torn apart 257 00:14:24,920 --> 00:14:27,580 by the incredibly strong magnetic fields. 258 00:14:27,590 --> 00:14:32,460 Then, the X-ray radiation would blast you to a crisp. 259 00:14:32,460 --> 00:14:34,290 And as it pulled you closer, 260 00:14:34,290 --> 00:14:36,690 its intense gravity would stretch out 261 00:14:36,690 --> 00:14:40,260 your atoms and molecules into a long, thin stream. 262 00:14:40,260 --> 00:14:43,130 You would build your speed faster and faster, 263 00:14:43,130 --> 00:14:46,240 and then, you would finally impact the surface, 264 00:14:46,240 --> 00:14:47,970 splatter across it. 265 00:14:47,970 --> 00:14:50,970 And that process would release as much energy 266 00:14:50,980 --> 00:14:52,110 as a nuclear bomb. 267 00:14:55,180 --> 00:14:58,380 If I had the choice between falling into a neutron star 268 00:14:58,380 --> 00:15:01,620 versus a black hole, I think I'd pick the black hole. 269 00:15:01,620 --> 00:15:03,720 'Cause I don't really feel like being torn apart 270 00:15:03,720 --> 00:15:06,360 by a magnetic field and blasted with x-rays. 271 00:15:10,760 --> 00:15:15,300 On a cosmic scale, neutron stars may be pint-sized, 272 00:15:15,300 --> 00:15:18,030 but they sure pack a serious punch. 273 00:15:18,040 --> 00:15:20,540 The secret to all this pent-up power 274 00:15:20,540 --> 00:15:25,070 is what's going on below the surface. 275 00:15:25,080 --> 00:15:27,610 Armed with the new kilonova data, 276 00:15:27,610 --> 00:15:29,350 we can now take a virtual journey 277 00:15:29,350 --> 00:15:32,080 into the heart of a neutron star. 278 00:15:32,080 --> 00:15:36,350 First, we must pass through its atmosphere. 279 00:15:36,350 --> 00:15:37,690 Now, it's not like the Earth's atmosphere, 280 00:15:37,690 --> 00:15:39,520 which goes up, like, a 100 miles. 281 00:15:39,520 --> 00:15:42,960 On a neutron star, the atmosphere is about this deep, 282 00:15:42,960 --> 00:15:48,130 and it's extremely dense compared to the air around us. 283 00:15:48,130 --> 00:15:52,770 Below the compressed atmosphere is a crust of ionized iron, 284 00:15:52,770 --> 00:15:55,170 a mixture of crystal iron nuclei, 285 00:15:55,170 --> 00:15:58,510 and free-flowing iron electrons. 286 00:15:58,510 --> 00:16:00,480 Now, the gravity's so strong 287 00:16:00,480 --> 00:16:02,910 that it's almost perfectly smooth. 288 00:16:02,910 --> 00:16:04,380 The biggest mountains on the surface 289 00:16:04,380 --> 00:16:06,780 are gonna be less than a quarter of an inch high. 290 00:16:06,780 --> 00:16:12,220 A quarter-inch mountain range may sound odd... 291 00:16:12,220 --> 00:16:16,530 But things get even stranger as we go below the surface. 292 00:16:18,630 --> 00:16:22,600 This is home to the strongest material in the universe. 293 00:16:25,670 --> 00:16:31,840 It's so weird, scientists liken it to nuclear pasta. 294 00:16:31,840 --> 00:16:34,810 As we dive beneath the crust of a neutron star, 295 00:16:34,810 --> 00:16:38,080 the neutrons themselves start to glue themselves together 296 00:16:38,080 --> 00:16:40,020 into exotic shapes. 297 00:16:40,020 --> 00:16:45,290 First, they form clumps that look something like gnocchi, 298 00:16:45,290 --> 00:16:48,360 then, deeper, the gnocchi glue themselves together 299 00:16:48,360 --> 00:16:52,330 to form long strands that look like spaghetti. 300 00:16:52,330 --> 00:16:54,930 Even deeper, the spaghetti fuse together 301 00:16:54,930 --> 00:16:58,400 to form sheets of lasagna. 302 00:16:58,400 --> 00:17:01,370 And then, finally, the lasagna fuse together 303 00:17:01,370 --> 00:17:05,980 to become a uniform mass, but with holes in it. 304 00:17:05,980 --> 00:17:08,410 So, it looks like penne. 305 00:17:08,410 --> 00:17:11,880 This is pasta, nuclear style, 306 00:17:11,880 --> 00:17:13,150 simmering at a temperature 307 00:17:13,150 --> 00:17:15,920 of over one million degrees Fahrenheit. 308 00:17:15,920 --> 00:17:19,690 Extreme gravity bends, squeezes, stretches, 309 00:17:19,690 --> 00:17:22,630 and buckles neutrons, creating a material 310 00:17:22,630 --> 00:17:26,930 100,000 billion times denser than iron. 311 00:17:26,930 --> 00:17:30,730 But the journey gets even more extreme. 312 00:17:30,740 --> 00:17:34,570 Even deeper is more mysterious and harder to understand. 313 00:17:34,570 --> 00:17:36,610 The core of a neutron star... 314 00:17:36,610 --> 00:17:39,340 Which is very far away from these layers, 315 00:17:39,340 --> 00:17:41,440 which we call the "nuclear pasta"... 316 00:17:41,450 --> 00:17:44,710 Is perhaps the most exotic form of matter. 317 00:17:44,720 --> 00:17:48,880 So exotic it might be the last bastion of matter 318 00:17:48,890 --> 00:17:53,220 before complete gravitational collapse into a black hole. 319 00:17:55,230 --> 00:17:57,530 Data from NASA's Chandra observatory 320 00:17:57,530 --> 00:18:00,900 suggests the core is made up of a super fluid... 321 00:18:00,900 --> 00:18:04,700 A bizarre friction-free state of matter. 322 00:18:04,700 --> 00:18:07,400 Similar super fluids produced in the lab 323 00:18:07,410 --> 00:18:09,440 exhibit strange properties, 324 00:18:09,440 --> 00:18:12,070 such as the ability to flow upwards 325 00:18:12,080 --> 00:18:16,010 and escape airtight containers. 326 00:18:16,010 --> 00:18:18,310 Although our knowledge of the star's interior 327 00:18:18,320 --> 00:18:20,550 is still hazy, there's not mystery 328 00:18:20,550 --> 00:18:22,690 about its dazzling birth. 329 00:18:22,690 --> 00:18:26,790 Forged into life during the most spectacular event 330 00:18:26,790 --> 00:18:28,720 the universe has to offer... 331 00:18:28,730 --> 00:18:32,230 The explosive death of a massive star. 332 00:18:48,600 --> 00:18:50,600 Neutron stars... 333 00:18:50,600 --> 00:18:57,170 Manhattan-sized, but with a mass twice that of our sun. 334 00:18:57,170 --> 00:19:03,240 So dense a teaspoon of their matter weighs a billion tons. 335 00:19:03,250 --> 00:19:07,580 Mind-blowing objects that arrive with a bang. 336 00:19:07,580 --> 00:19:09,550 Neutron stars spark into life 337 00:19:09,550 --> 00:19:11,520 amid the death of their parent star. 338 00:19:11,520 --> 00:19:14,220 They're the ultimate story of resurrection, 339 00:19:14,220 --> 00:19:16,890 or of life from death. 340 00:19:16,890 --> 00:19:20,960 It's all part of a cosmic cycle. 341 00:19:20,960 --> 00:19:25,300 Stars are born from giant clouds of very cold gas. 342 00:19:25,300 --> 00:19:28,340 Those clouds collapse under their own gravity, 343 00:19:28,340 --> 00:19:31,470 and the density of the core at the center of the collapse 344 00:19:31,470 --> 00:19:32,640 starts to increase. 345 00:19:37,750 --> 00:19:41,680 A star is a huge nuclear fusion reactor. 346 00:19:41,680 --> 00:19:44,250 The force of its gravity is so powerful 347 00:19:44,250 --> 00:19:46,020 that it fuses atoms together 348 00:19:46,020 --> 00:19:50,920 to make progressively heavier and heavier elements. 349 00:19:50,930 --> 00:19:54,060 The star fuses hydrogen into helium. 350 00:19:54,060 --> 00:19:57,260 Once it exhausts its hydrogen, then, if it's massive enough, 351 00:19:57,270 --> 00:19:59,700 it can start fusing helium at its core. 352 00:20:02,140 --> 00:20:04,800 Fusion continues, forming carbon, 353 00:20:04,810 --> 00:20:10,780 oxygen, nitrogen, all the way up to iron. 354 00:20:10,780 --> 00:20:13,110 Once a star has iron in the core, 355 00:20:13,120 --> 00:20:15,080 it's almost like you've poisoned it, 356 00:20:15,080 --> 00:20:18,750 because this extinguishes the nuclear reactions 357 00:20:18,750 --> 00:20:20,090 in the core of the star. 358 00:20:20,090 --> 00:20:24,320 You fuse something into iron, and you get no energy. 359 00:20:24,330 --> 00:20:26,160 All of a sudden, there's nothing to support 360 00:20:26,160 --> 00:20:27,430 the crush of gravity. 361 00:20:27,430 --> 00:20:29,130 No radiation pressure pushing out 362 00:20:29,130 --> 00:20:33,100 means no pressure keeping the outer regions from falling in, 363 00:20:33,100 --> 00:20:34,970 and that's what they do. 364 00:20:34,970 --> 00:20:38,070 As the star collapses in its death throes, 365 00:20:38,070 --> 00:20:41,510 its core becomes the wildest, craziest, 366 00:20:41,510 --> 00:20:45,750 and freakiest pressure cooker in the whole universe. 367 00:20:47,880 --> 00:20:50,350 The ingredients are all in place. 368 00:20:50,350 --> 00:20:55,220 It's time to start cooking up a neutron star. 369 00:20:55,220 --> 00:20:57,960 If we were to scale up an atomic nucleus 370 00:20:57,960 --> 00:20:59,830 to be the size of a baseball, 371 00:20:59,830 --> 00:21:04,000 in a normal atom, the nearest electron would be 372 00:21:04,000 --> 00:21:06,030 way over in those trees, 373 00:21:06,030 --> 00:21:08,130 but in the extreme conditions that lead to 374 00:21:08,140 --> 00:21:10,300 the formation of a neutron star, 375 00:21:10,310 --> 00:21:14,340 those electrons can be pushed closer to the nucleus. 376 00:21:14,340 --> 00:21:17,510 They can come zipping in from any direction. 377 00:21:17,510 --> 00:21:20,410 And if the temperatures and pressures are high enough, 378 00:21:20,420 --> 00:21:22,380 they can even strike the nucleus 379 00:21:22,380 --> 00:21:25,290 and enter it, and they can hit a proton. 380 00:21:25,290 --> 00:21:29,820 And when they do, they become converted into more neutrons. 381 00:21:29,830 --> 00:21:32,460 So, in the formation of one of these objects, 382 00:21:32,460 --> 00:21:34,790 the protons and electrons disappear, 383 00:21:34,800 --> 00:21:37,800 and you're left with almost entirely pure neutrons, 384 00:21:37,800 --> 00:21:40,870 with nothing to stop them from cramming together 385 00:21:40,870 --> 00:21:43,740 and filling up this entire baseball 386 00:21:43,740 --> 00:21:49,280 with neutrons leading to incredibly high densities. 387 00:21:49,280 --> 00:21:50,640 With the sea of electrons 388 00:21:50,650 --> 00:21:53,210 now absorbed in the atomic nuclei, 389 00:21:53,220 --> 00:21:58,150 the matter in the stars can now press together a lot tighter. 390 00:21:58,150 --> 00:22:01,350 It's like squeezing 300 million tons of mass 391 00:22:01,360 --> 00:22:04,690 into a single sugar cube. 392 00:22:04,690 --> 00:22:06,460 As the star collapses, 393 00:22:06,460 --> 00:22:09,630 enormous amounts of gas fall towards the core. 394 00:22:12,300 --> 00:22:16,800 The core is small in size, but huge in mass. 395 00:22:16,810 --> 00:22:19,610 Billions of tons of gas bounce off of it, 396 00:22:19,610 --> 00:22:23,080 then erupt into the biggest fireworks display 397 00:22:23,080 --> 00:22:28,550 in the cosmos... A supernova. 398 00:22:28,550 --> 00:22:29,850 It's massive. 399 00:22:29,850 --> 00:22:30,950 It's bright. 400 00:22:30,950 --> 00:22:32,250 It's imposing. 401 00:22:32,250 --> 00:22:35,360 Supernova are among the most dramatic events 402 00:22:35,360 --> 00:22:36,820 to happen in the universe. 403 00:22:36,830 --> 00:22:38,460 A single star dying... 404 00:22:38,460 --> 00:22:43,530 One star dying... Can outshine an entire galaxy. 405 00:22:47,370 --> 00:22:49,840 And arising out of this cataclysm, 406 00:22:49,840 --> 00:22:53,270 a new and very strange cosmic entity. 407 00:22:56,240 --> 00:22:59,110 When the smoke finally clears from the supernova explosion, 408 00:22:59,110 --> 00:23:01,850 you're left with one of the most real, fascinating, 409 00:23:01,850 --> 00:23:05,020 unbelievable monsters of the entire universe. 410 00:23:05,020 --> 00:23:06,690 Humans have been witnessing supernovas 411 00:23:06,690 --> 00:23:08,320 for thousands of years, 412 00:23:08,320 --> 00:23:11,060 but we're only now just starting to understand 413 00:23:11,060 --> 00:23:13,860 what we've truly been witnessing... 414 00:23:13,860 --> 00:23:17,800 The births of neutron stars. 415 00:23:17,800 --> 00:23:20,900 But while supernovas are big and bright, 416 00:23:20,900 --> 00:23:23,440 neutron stars are small, 417 00:23:23,440 --> 00:23:26,610 and many don't even give off light. 418 00:23:26,610 --> 00:23:30,580 So, how many neutron stars are out there? 419 00:23:30,580 --> 00:23:34,150 We know of about 2,000 neutron stars in our galaxy, 420 00:23:34,150 --> 00:23:35,750 but there probably are many, many, more. 421 00:23:35,750 --> 00:23:38,590 I'm talking about tens of millions in the milky way alone, 422 00:23:38,590 --> 00:23:42,860 and certainly billions throughout the universe. 423 00:23:42,860 --> 00:23:48,660 Neutron stars may be small, but some give themselves away, 424 00:23:48,660 --> 00:23:52,130 shooting beams across the universe... 425 00:23:52,130 --> 00:23:57,400 Unmistakable, pulsing strobes of a cosmic lighthouse. 426 00:24:16,400 --> 00:24:20,900 Our knowledge of neutron stars is expanding fast. 427 00:24:23,440 --> 00:24:25,540 But we didn't even know they existed 428 00:24:25,540 --> 00:24:29,110 until a lucky discovery just over 50 years ago. 429 00:24:31,140 --> 00:24:34,280 Cambridge, the Mullard radio observatory, 430 00:24:34,280 --> 00:24:36,180 Jocelyn bell, grad student, 431 00:24:36,180 --> 00:24:39,750 operating the new radio telescope. 432 00:24:39,750 --> 00:24:42,850 Scanning the sky, doing all sorts of cool astronomy stuff, 433 00:24:42,860 --> 00:24:48,290 and sees what she calls "a bit of scruff" in the data. 434 00:24:48,290 --> 00:24:49,730 This scruff is a short 435 00:24:49,730 --> 00:24:53,060 but constantly repeating burst of radiation 436 00:24:53,070 --> 00:24:57,340 originating 1,000 light years from earth. 437 00:24:57,340 --> 00:25:00,470 It's so stable and regular that bell is convinced 438 00:25:00,470 --> 00:25:03,240 there's a fault with her telescope. 439 00:25:03,240 --> 00:25:05,180 She returns to that spot, 440 00:25:05,180 --> 00:25:09,480 and finds a repeating, regular signal... 441 00:25:09,480 --> 00:25:15,020 A single point in the sky that is flashing at us continually, 442 00:25:15,020 --> 00:25:17,820 saying "Hi. Hi. Hi." 443 00:25:17,820 --> 00:25:19,520 Blip, blip, blip. 444 00:25:19,530 --> 00:25:21,890 Boom, boom, boom. 445 00:25:21,900 --> 00:25:23,790 Pulse, pulse, pulse. 446 00:25:23,800 --> 00:25:25,800 Nothing that we know of in the universe, 447 00:25:25,800 --> 00:25:30,370 has such a steady, perfectly-spaced in time, pulse. 448 00:25:30,370 --> 00:25:34,610 It seemed so perfect that it must have been artificial. 449 00:25:34,610 --> 00:25:37,980 It looks like someone is making that, 450 00:25:37,980 --> 00:25:41,950 but it turns out, it's not a person, but a thing. 451 00:25:41,950 --> 00:25:44,820 What she discovered was called a "pulsar." 452 00:25:47,650 --> 00:25:50,250 A pulsar is a type of rapidly spinning 453 00:25:50,260 --> 00:25:51,620 neutron star. 454 00:25:54,430 --> 00:25:58,300 Neutron stars had been theorized in the 1930s, 455 00:25:58,300 --> 00:26:02,200 but were thought to be too faint to be detected. 456 00:26:02,200 --> 00:26:06,800 Neutron stars were hypothesized to exist, 457 00:26:06,810 --> 00:26:09,710 but not really taken seriously. 458 00:26:09,710 --> 00:26:12,180 It was just a, "oh, that's cute. 459 00:26:12,180 --> 00:26:14,780 Maybe they're out there, but probably not." 460 00:26:15,920 --> 00:26:17,750 The signal bell detected 461 00:26:17,750 --> 00:26:21,750 seemed like something from science fiction. 462 00:26:21,750 --> 00:26:24,520 No one had ever seen this in astronomy before, 463 00:26:24,520 --> 00:26:28,660 and some people even speculated that it was an alien signal. 464 00:26:28,660 --> 00:26:31,000 She even called them "LGM objects"... 465 00:26:31,000 --> 00:26:33,970 "little green men." 466 00:26:33,970 --> 00:26:36,470 But then, bell found a second signal. 467 00:26:39,310 --> 00:26:42,470 Little green men went back to being fiction, 468 00:26:42,480 --> 00:26:46,140 and pulsars became science fact. 469 00:26:46,150 --> 00:26:48,410 The discovery of pulsars came out of the blue. 470 00:26:48,410 --> 00:26:50,010 Nobody was expecting this. 471 00:26:50,020 --> 00:26:52,220 So, it was an amazing breakthrough... 472 00:26:52,220 --> 00:26:53,420 Really important. 473 00:26:56,590 --> 00:27:00,990 Pulsars pulse because they are born to spin. 474 00:27:00,990 --> 00:27:05,230 They burst into life as their parent star collapses 475 00:27:05,230 --> 00:27:06,760 during a supernova. 476 00:27:08,940 --> 00:27:11,300 Any object at all that is undergoing 477 00:27:11,300 --> 00:27:13,440 any sort of compression event, 478 00:27:13,440 --> 00:27:16,670 if it has any initial angular momentum at all, 479 00:27:16,680 --> 00:27:20,780 it will eventually end up spinning. 480 00:27:20,780 --> 00:27:24,880 As the star shrinks, it spins faster and faster. 481 00:27:26,850 --> 00:27:30,990 They spin so quickly because the Earth-sized core 482 00:27:30,990 --> 00:27:32,360 of a massive star 483 00:27:32,360 --> 00:27:35,630 collapsed to something as small as a city. 484 00:27:35,630 --> 00:27:39,730 So, because the size of the object became so much smaller, 485 00:27:39,730 --> 00:27:44,470 the rate of spin had to increase by a tremendous amount. 486 00:27:44,470 --> 00:27:47,740 Neutron stars can spin really, really, fast. 487 00:27:47,740 --> 00:27:50,210 Their surface is moving so fast. 488 00:27:50,210 --> 00:27:54,010 It's moving at about 20% the speed of light, in some cases. 489 00:27:54,010 --> 00:27:57,280 So, if you were to get on the neutron star ride... 490 00:27:57,280 --> 00:28:01,250 No pregnant women, no bad backs, no heart issues, 491 00:28:01,250 --> 00:28:04,020 keep your arms and legs inside the ride at all times, 492 00:28:04,020 --> 00:28:06,360 because they are about to be obliterated. 493 00:28:08,260 --> 00:28:13,530 And as they spin, they generate flashing beams of energy. 494 00:28:13,530 --> 00:28:15,930 This beam is like a lighthouse beam. 495 00:28:15,940 --> 00:28:19,340 You see these periodic flashes many times per second. 496 00:28:19,340 --> 00:28:24,210 So, every time you see it... Beam, beam, beam. 497 00:28:24,210 --> 00:28:27,210 These beams are the pulsar's calling card. 498 00:28:27,210 --> 00:28:29,910 They're generated by the elemental chaos 499 00:28:29,920 --> 00:28:32,550 raging inside a neutron star. 500 00:28:32,550 --> 00:28:34,420 Although the star is predominantly 501 00:28:34,420 --> 00:28:36,290 a ball of neutrons, 502 00:28:36,290 --> 00:28:40,020 the crust is sprinkled with protons and electrons, 503 00:28:40,030 --> 00:28:42,260 spinning hundreds of times a second, 504 00:28:42,260 --> 00:28:45,000 generating an incredible magnetic field. 505 00:28:46,700 --> 00:28:48,530 And with this strong magnetic field, 506 00:28:48,530 --> 00:28:50,630 you can create strong electric fields. 507 00:28:50,640 --> 00:28:52,300 And the electric and magnetic fields 508 00:28:52,310 --> 00:28:55,910 can work off of each other and become radiation. 509 00:28:55,910 --> 00:29:01,680 These neutron stars send jets... Beams of radiation... 510 00:29:01,680 --> 00:29:03,780 Out of their spinning poles. 511 00:29:03,780 --> 00:29:06,250 And if their spinning pole is misaligned, 512 00:29:06,250 --> 00:29:07,850 if they're a little bit tilted, 513 00:29:07,850 --> 00:29:12,120 this beam will make circles, across the universe. 514 00:29:12,130 --> 00:29:14,890 And if we're in the path of one of these circles, 515 00:29:14,890 --> 00:29:18,630 we'll see a flash... A flash. 516 00:29:18,630 --> 00:29:20,300 Just like if you're on a ship, 517 00:29:20,300 --> 00:29:22,970 and you observe a distant lighthouse in a foggy night, 518 00:29:22,970 --> 00:29:26,940 you can see pulsars across the vast expanse of space 519 00:29:26,940 --> 00:29:30,540 because they are immensely powerful beams of light. 520 00:29:30,540 --> 00:29:33,840 But sometimes, pulsars get an extra push 521 00:29:33,850 --> 00:29:37,620 that accelerates the spin even more. 522 00:29:37,620 --> 00:29:39,750 The way you make it spin even faster 523 00:29:39,750 --> 00:29:42,920 is by subsequently dumping more material onto it. 524 00:29:42,920 --> 00:29:45,420 That's called "accretion," and you end up spinning it up 525 00:29:45,430 --> 00:29:47,530 even faster than it was already spinning. 526 00:29:47,530 --> 00:29:49,630 Like stellar vampires, 527 00:29:49,630 --> 00:29:51,860 pulsars are ready to suck the life 528 00:29:51,860 --> 00:29:55,270 out of any objects that stray too close. 529 00:29:55,270 --> 00:29:57,700 Gravity is bringing that material in, 530 00:29:57,700 --> 00:30:00,370 which means that any spin it has is accelerated. 531 00:30:00,370 --> 00:30:02,170 It spins faster and faster. 532 00:30:02,180 --> 00:30:04,480 These millisecond pulsars 533 00:30:04,480 --> 00:30:08,680 spin at around 700 revolutions per second. 534 00:30:08,680 --> 00:30:10,780 They are the ultimate kitchen blender... 535 00:30:10,780 --> 00:30:15,120 They will chop, they will slice, they will even julienne fry. 536 00:30:17,820 --> 00:30:19,860 So, what stops neutron stars 537 00:30:19,860 --> 00:30:23,030 from simply tearing themselves apart? 538 00:30:23,030 --> 00:30:26,330 Neutron stars are incredibly exotic objects 539 00:30:26,330 --> 00:30:30,370 with immense, immense forces that bind them together, 540 00:30:30,370 --> 00:30:32,570 and so, they can be held rigid even against 541 00:30:32,570 --> 00:30:34,870 these incredibly fast rotation speeds. 542 00:30:38,540 --> 00:30:40,410 They have incredibly strong gravity, 543 00:30:40,410 --> 00:30:42,310 and this is what allows them to hold together 544 00:30:42,320 --> 00:30:44,480 even though they're spinning around so fast. 545 00:30:47,550 --> 00:30:52,920 The speed of the spin is hard to imagine. 546 00:30:52,930 --> 00:30:55,090 On earth, a day is 24 hours long. 547 00:30:55,090 --> 00:31:00,130 On a neutron star, it's a 700th of a second long. 548 00:31:00,130 --> 00:31:04,170 Super-speeding pulsars are not the only weird stars 549 00:31:04,170 --> 00:31:06,700 that scientists are coming to grips with. 550 00:31:06,710 --> 00:31:09,070 There is one other type of neutron star, 551 00:31:09,080 --> 00:31:12,980 that has the most powerful magnetic field in the universe. 552 00:31:12,980 --> 00:31:17,380 This magnetic monster is called a "magnetar." 553 00:31:33,200 --> 00:31:36,340 Astronomers monitoring pulsing neutron stars 554 00:31:36,340 --> 00:31:39,310 have noticed something very odd. 555 00:31:39,310 --> 00:31:44,910 On very rare occasions, they can suddenly speed up. 556 00:31:44,920 --> 00:31:46,110 That's amazing. 557 00:31:46,120 --> 00:31:48,120 I mean, you've got this incredibly dense object, 558 00:31:48,120 --> 00:31:49,550 and suddenly, it's spinning faster. 559 00:31:49,550 --> 00:31:51,620 It happens... Instantly. 560 00:31:51,620 --> 00:31:53,460 They'll suddenly change frequency. 561 00:31:53,460 --> 00:31:56,730 It would take an amazing amount of power to do that. 562 00:31:56,730 --> 00:31:58,330 What's doing it? 563 00:31:58,330 --> 00:32:03,030 These sudden changes in speed are called "glitches." 564 00:32:03,030 --> 00:32:05,400 One leading idea for what causes these glitches 565 00:32:05,400 --> 00:32:08,040 is that the core material latches onto the crust, 566 00:32:08,040 --> 00:32:11,240 and this affects the way it can spin around. 567 00:32:11,240 --> 00:32:15,110 Excess material beneath the crust cracks it open, 568 00:32:15,110 --> 00:32:17,110 causing the glitch. 569 00:32:17,110 --> 00:32:21,020 This process releases a tremendous amount of radiation, 570 00:32:21,020 --> 00:32:25,550 a blast of x-rays, causes the face of the neutron star 571 00:32:25,560 --> 00:32:29,920 to rearrange itself, and for the rotation speed to change. 572 00:32:29,930 --> 00:32:32,530 But there's another possible explanation. 573 00:32:32,530 --> 00:32:36,870 Glitches could also be caused by starquakes. 574 00:32:36,870 --> 00:32:39,330 Sometimes, the crust gets ruptured. 575 00:32:39,340 --> 00:32:43,470 Anything that basically changes the geometry of the pulsar 576 00:32:43,470 --> 00:32:46,440 can change the rate at which it spins. 577 00:32:46,440 --> 00:32:47,940 So, what could be powerful enough 578 00:32:47,940 --> 00:32:51,280 to cause these starquakes? 579 00:32:51,280 --> 00:32:52,310 It's hard to believe 580 00:32:52,320 --> 00:32:54,650 that there's any force in the universe 581 00:32:54,650 --> 00:32:57,720 that could deform the matter inside of a neutron star, 582 00:32:57,720 --> 00:33:00,490 which is undergoing tremendous gravity. 583 00:33:00,490 --> 00:33:02,220 But when it comes to a neutron star, 584 00:33:02,230 --> 00:33:05,430 if there's one thing that can do it, it's magnetism. 585 00:33:05,430 --> 00:33:07,160 Extreme magnetic fields 586 00:33:07,160 --> 00:33:09,960 within the star can get so twisted 587 00:33:09,970 --> 00:33:12,670 they can rip the crust wide open. 588 00:33:12,670 --> 00:33:15,270 And so, the surface can restructure itself, 589 00:33:15,270 --> 00:33:16,840 and constantly reshape. 590 00:33:16,840 --> 00:33:19,510 And just a tiny reconfiguration 591 00:33:19,510 --> 00:33:21,280 of the surface of a neutron star, 592 00:33:21,280 --> 00:33:22,910 on the order of a few millimeters, 593 00:33:22,910 --> 00:33:27,380 would be associated with an enormous release of energy. 594 00:33:27,380 --> 00:33:29,550 The neutron star's immense gravity 595 00:33:29,550 --> 00:33:34,690 smooths over the star's surface almost instantaneously. 596 00:33:34,690 --> 00:33:37,230 It's like the glitch never happened. 597 00:33:40,700 --> 00:33:42,800 When it comes to neutron stars, 598 00:33:42,800 --> 00:33:47,400 there is no end to magnetic mayhem. 599 00:33:47,400 --> 00:33:49,370 Meet the reigning champion 600 00:33:49,370 --> 00:33:53,910 in the universal "strongest magnetic field" competition... 601 00:33:53,910 --> 00:33:56,410 The magnetar. 602 00:33:56,410 --> 00:33:59,980 1 in 10 neutron stars formed during a supernova 603 00:33:59,980 --> 00:34:02,480 becomes a magnetar. 604 00:34:02,490 --> 00:34:07,060 The thing about magnetars, as is implied in their name... 605 00:34:07,060 --> 00:34:09,360 The magnetic field on them is so strong, 606 00:34:09,360 --> 00:34:11,890 that even somebody who is used to using big numbers... 607 00:34:11,900 --> 00:34:13,660 Like, say, an astronomer... 608 00:34:13,660 --> 00:34:16,730 Is still kind of in awe of these things. 609 00:34:16,730 --> 00:34:19,100 Magnetars have a magnetic field 610 00:34:19,100 --> 00:34:23,270 one thousand trillion times stronger than that of earth's. 611 00:34:23,270 --> 00:34:25,170 This amount of magnetism 612 00:34:25,180 --> 00:34:29,980 will seriously mess up anything that comes close. 613 00:34:29,980 --> 00:34:32,480 Any normal object that we are familiar with, 614 00:34:32,480 --> 00:34:36,120 if it got close to a magnetar, it would just be shredded. 615 00:34:36,120 --> 00:34:38,420 Any charged particle with any movement at all, 616 00:34:38,420 --> 00:34:40,260 would just be torn from its atom. 617 00:34:40,260 --> 00:34:43,660 It would be just an insane situation. 618 00:34:43,660 --> 00:34:48,060 Magnetars burn brightly, but their lives are brief. 619 00:34:48,060 --> 00:34:49,330 We think magnetars... 620 00:34:49,330 --> 00:34:51,970 These intensely magnetized neutron stars... 621 00:34:51,970 --> 00:34:53,900 Can only be really short-lived. 622 00:34:53,900 --> 00:34:56,170 Their magnetic field is so powerful 623 00:34:56,170 --> 00:34:58,710 that it should decay over very rapid time scales, 624 00:34:58,710 --> 00:35:01,240 only on the order of a few ten thousand years. 625 00:35:01,240 --> 00:35:05,710 It seems their very strength leads to their downfall. 626 00:35:05,720 --> 00:35:07,650 That magnetic field is so strong 627 00:35:07,650 --> 00:35:10,690 that it's picking up material around it, and accelerating it. 628 00:35:10,690 --> 00:35:12,720 Well, that acts like a drag, slowing it down. 629 00:35:12,720 --> 00:35:15,890 So, over time, the spin of the neutron star slows, 630 00:35:15,890 --> 00:35:17,730 and the magnetic field dies away. 631 00:35:20,030 --> 00:35:21,330 During their lives, 632 00:35:21,330 --> 00:35:24,930 magnetars operate very differently than pulsars. 633 00:35:24,940 --> 00:35:26,570 They don't have beams. 634 00:35:26,570 --> 00:35:29,540 Their magnetic fields shoot out gigantic bursts 635 00:35:29,540 --> 00:35:32,970 of high-intensity radiation. 636 00:35:32,980 --> 00:35:36,640 But recently, astronomers have spotted one neutron star 637 00:35:36,650 --> 00:35:39,110 that's hard to classify. 638 00:35:39,120 --> 00:35:43,380 It behaves like a stellar Jekyll and Hyde. 639 00:35:45,000 --> 00:35:48,900 So, this particular neutron star is a really weird example. 640 00:35:48,900 --> 00:35:51,270 It behaves both like a radio pulsar, 641 00:35:51,270 --> 00:35:54,210 and also a highly-magnetized magnetar. 642 00:35:54,210 --> 00:35:56,540 It has the extreme magnetic fields, 643 00:35:56,540 --> 00:35:59,280 it can have these magnetic outbursts, 644 00:35:59,280 --> 00:36:02,010 but it also has this strong jet of radiation 645 00:36:02,020 --> 00:36:03,280 coming out of its poles. 646 00:36:03,280 --> 00:36:07,320 It's almost like it has a split personality. 647 00:36:07,320 --> 00:36:09,590 When first sighted in 2000, 648 00:36:09,590 --> 00:36:12,090 this star was emitting radio waves... 649 00:36:12,090 --> 00:36:15,030 Typical pulsar behavior. 650 00:36:15,030 --> 00:36:19,030 Then, 16 years later, it stopped pulsing, 651 00:36:19,030 --> 00:36:23,470 and suddenly started sending out massive X-ray bursts... 652 00:36:23,470 --> 00:36:26,400 The actions of a magnetar. 653 00:36:26,410 --> 00:36:29,440 Scientists were baffled. 654 00:36:29,440 --> 00:36:32,640 We don't know if this thing is a pulsar turning into a magnetar, 655 00:36:32,650 --> 00:36:35,210 or a magnetar turning into a pulsar. 656 00:36:35,220 --> 00:36:38,150 One theory is that these X-ray bursts happened 657 00:36:38,150 --> 00:36:42,220 because the star's magnetic field suddenly twisted. 658 00:36:42,220 --> 00:36:46,660 The stress became so great, the star cracked wide open, 659 00:36:46,660 --> 00:36:50,660 releasing the X-rays from the fractured crust. 660 00:36:50,660 --> 00:36:52,930 A neutron star is the densest material 661 00:36:52,930 --> 00:36:54,870 that we know of in the universe. 662 00:36:54,870 --> 00:36:56,100 And yet, we've seen things 663 00:36:56,100 --> 00:36:58,540 that actually make it shift and pull apart. 664 00:36:58,540 --> 00:37:01,170 This neutron star is actually ripping itself apart 665 00:37:01,180 --> 00:37:03,240 under the forces of the magnetic field. 666 00:37:03,240 --> 00:37:04,740 If this is the case, 667 00:37:04,750 --> 00:37:09,310 placid neutron stars turn into raging magnetars, 668 00:37:09,320 --> 00:37:12,750 growing old disgracefully. 669 00:37:12,750 --> 00:37:14,750 When you think about the life cycle of a human being, 670 00:37:14,760 --> 00:37:16,590 we seem to kind of slow down over age, 671 00:37:16,590 --> 00:37:18,060 become a little more calmer. 672 00:37:18,060 --> 00:37:19,720 Neutron stars do the opposite. 673 00:37:19,730 --> 00:37:21,530 They can be spinning faster than they were 674 00:37:21,530 --> 00:37:22,830 when they were formed, 675 00:37:22,830 --> 00:37:25,160 and the magnetic field can get stronger over time. 676 00:37:25,170 --> 00:37:28,330 It's sort of a reverse aging process. 677 00:37:28,340 --> 00:37:31,600 But these strange changes are extremely rare. 678 00:37:31,610 --> 00:37:36,680 Most pulsars are as regular as clockwork. 679 00:37:36,680 --> 00:37:38,640 Pulsars are normally incredibly regular. 680 00:37:38,650 --> 00:37:41,810 You can literally set your watch to the timing of their pulse. 681 00:37:41,820 --> 00:37:44,380 And it's this stability that we may use 682 00:37:44,380 --> 00:37:48,020 in our future exploration of the universe. 683 00:37:48,020 --> 00:37:49,890 You know, if you're a starship captain, 684 00:37:49,890 --> 00:37:53,060 what you need is a galactic GPS system. 685 00:37:53,060 --> 00:37:56,190 Well it turns out, neutron stars may be the answer. 686 00:38:11,600 --> 00:38:13,440 Astronomers often compare 687 00:38:13,440 --> 00:38:17,710 the steady flash of spinning neutron stars, called "pulsars," 688 00:38:17,710 --> 00:38:19,780 to cosmic lighthouses. 689 00:38:19,780 --> 00:38:23,550 These flashes are not only remarkably reliable, 690 00:38:23,550 --> 00:38:29,090 each pulsar has its very own distinct flickering beam. 691 00:38:29,090 --> 00:38:31,520 Each one has a slightly different frequency. 692 00:38:31,520 --> 00:38:34,360 Each one has a slightly different rate. 693 00:38:34,360 --> 00:38:37,730 Anyone in the galaxy, no matter where you are, 694 00:38:37,730 --> 00:38:43,970 can all agree on the positions of these pulsars. 695 00:38:43,970 --> 00:38:46,300 The unique signature of pulsars 696 00:38:46,300 --> 00:38:48,940 opens up intriguing possibilities 697 00:38:48,940 --> 00:38:50,540 for the future of space travel. 698 00:38:55,980 --> 00:38:58,380 We would basically be using pulsars 699 00:38:58,380 --> 00:39:01,280 to be able to sort of triangulate where we're at. 700 00:39:01,290 --> 00:39:03,650 And because those pulses are so precise, 701 00:39:03,660 --> 00:39:06,860 we can use that in a similar way that we use GPS satellites 702 00:39:06,860 --> 00:39:08,390 that are stationed above the Earth. 703 00:39:11,330 --> 00:39:14,200 Using pulsars as navigational aids 704 00:39:14,200 --> 00:39:16,030 is not a new idea. 705 00:39:16,030 --> 00:39:19,400 It was recognized by the NASA voyager mission 706 00:39:19,400 --> 00:39:22,410 in the 1970's. 707 00:39:22,410 --> 00:39:24,770 Affixed to the surface of those spacecraft 708 00:39:24,780 --> 00:39:26,040 is a golden record. 709 00:39:26,040 --> 00:39:28,040 And on the plate that covers that record 710 00:39:28,050 --> 00:39:31,480 is a pulsar map, which in principle could tell 711 00:39:31,480 --> 00:39:34,880 an advanced alien civilization how to find earth, 712 00:39:34,890 --> 00:39:37,390 because it uses the position of earth 713 00:39:37,390 --> 00:39:39,560 relative to 14 known pulsars, 714 00:39:39,560 --> 00:39:41,720 as, effectively, a way to triangulate 715 00:39:41,730 --> 00:39:43,260 the position of our planet 716 00:39:43,260 --> 00:39:46,200 relative to all of these pulsars. 717 00:39:46,200 --> 00:39:52,200 Aliens haven't made contact, but NASA still uses pulsar maps. 718 00:39:52,200 --> 00:39:54,100 NASA recently launched a satellite 719 00:39:54,110 --> 00:39:55,740 called "nicer sextant" 720 00:39:55,740 --> 00:39:58,340 that exists on the international space station, 721 00:39:58,340 --> 00:40:01,040 that is being used to test these types of theories. 722 00:40:09,750 --> 00:40:12,220 They've used pulsars to figure out the location 723 00:40:12,220 --> 00:40:14,220 of an object orbiting around the Earth 724 00:40:14,230 --> 00:40:16,530 at 17,000 miles an hour, 725 00:40:16,530 --> 00:40:18,360 and they were able to pinpoint its location 726 00:40:18,360 --> 00:40:19,860 to within three miles. 727 00:40:19,860 --> 00:40:21,930 That's pretty incredible. 728 00:40:21,930 --> 00:40:26,300 By recognizing their position relative to known pulsars, 729 00:40:26,300 --> 00:40:30,010 future space missions could navigate the universe. 730 00:40:36,550 --> 00:40:39,520 Neutron stars are gonna take us on this incredible journey... 731 00:40:39,520 --> 00:40:40,950 Something as necessary 732 00:40:40,950 --> 00:40:42,820 as knowing where you are in the galaxy. 733 00:40:42,820 --> 00:40:44,720 We could be many hundreds of light years away, 734 00:40:44,720 --> 00:40:46,520 but neutron stars can actually show us 735 00:40:46,520 --> 00:40:48,090 where in the milky way we are. 736 00:40:55,900 --> 00:40:57,200 I read a lot of science fiction, 737 00:40:57,200 --> 00:40:59,900 and I love the idea of being able to go 738 00:40:59,900 --> 00:41:02,470 from star to star, planet to planet. 739 00:41:02,470 --> 00:41:06,240 It's kind of weird to think that, in the future, 740 00:41:06,240 --> 00:41:08,750 as a galactic coordinate grid, 741 00:41:08,750 --> 00:41:12,980 we might wind up using these gigantic atomic nuclei, 742 00:41:12,980 --> 00:41:16,090 these rapidly spinning, bizarrely-constructed, 743 00:41:16,090 --> 00:41:20,560 magnetic, fiercely gravitational objects like neutron stars. 744 00:41:23,660 --> 00:41:26,500 Neutron stars have come a long way 745 00:41:26,500 --> 00:41:31,200 since being mistaken for little green men. 746 00:41:31,200 --> 00:41:35,740 Once overlooked as astronomical oddities, 747 00:41:35,740 --> 00:41:43,180 they've now taken center stage as genuine stellar superstars. 748 00:41:43,180 --> 00:41:45,620 What's really exciting about neutron stars is that, 749 00:41:45,620 --> 00:41:47,920 we're at the beginning of studying them. 750 00:41:47,920 --> 00:41:50,250 We're not at the conclusion. We've learned a lot, 751 00:41:50,260 --> 00:41:52,090 but there's a lot more to be learned. 752 00:41:52,090 --> 00:41:56,760 From the humble neutron comes the most powerful, 753 00:41:56,760 --> 00:42:00,200 the most rapid, the strongest magnetic field, 754 00:42:00,200 --> 00:42:04,030 the most exotic objects in the cosmos. 755 00:42:04,040 --> 00:42:05,740 I love the idea of a Phoenix, 756 00:42:05,740 --> 00:42:08,270 something actually rising from its own ashes. 757 00:42:08,270 --> 00:42:10,840 You think something dies, and that's the end of the story, 758 00:42:10,840 --> 00:42:12,410 but something even more beautiful, 759 00:42:12,410 --> 00:42:14,840 even more fascinating, comes afterwards. 760 00:42:14,850 --> 00:42:17,080 I told you at the beginning, and you didn't believe me, 761 00:42:17,080 --> 00:42:18,450 but now, I hope you do... 762 00:42:18,450 --> 00:42:21,050 Neutron stars are the most fascinating 763 00:42:21,050 --> 00:42:23,690 astrophysical objects in the universe. 764 00:42:23,740 --> 00:42:28,290 Repair and Synchronization by Easy Subtitles Synchronizer 1.0.0.0 61511

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