1 00:00:02,567 --> 00:00:06,266 ROWE: You might have seen a boxing match on TV. 2 00:00:06,367 --> 00:00:08,900 Maybe you've even seen one live. 3 00:00:09,000 --> 00:00:12,867 But you have never seen a contest like this. 4 00:00:12,967 --> 00:00:18,467 Take your ringside seat to the fight of the cosmos. 5 00:00:18,567 --> 00:00:20,900 This is gonna be a wonderful fight to witness. 6 00:00:21,000 --> 00:00:23,367 But you'll want to be a few 7 00:00:23,367 --> 00:00:25,100 million billion light-years away. 8 00:00:25,166 --> 00:00:28,567 It's like being punched by the ghost of Muhammad Ali. 9 00:00:28,667 --> 00:00:30,000 You don't even see it coming. 10 00:00:30,000 --> 00:00:30,100 You don't even see it coming. 11 00:00:30,166 --> 00:00:34,367 ROWE: Our fighters don't float like a butterfly or sting like 12 00:00:34,467 --> 00:00:39,367 a bee, but they can deliver the ultimate knockout blow. 13 00:00:39,367 --> 00:00:45,200 It is a soul-chilling, mind-crushing amount of energy. 14 00:00:45,266 --> 00:00:47,166 It's just unbelievable. 15 00:00:47,266 --> 00:00:50,700 ROWE: It's a fight between two supermassive black holes. 16 00:00:50,767 --> 00:00:53,467 Forget about the world heavyweight championships. 17 00:00:53,567 --> 00:00:56,567 This is the universe's heavyweight championships. 18 00:00:57,600 --> 00:00:59,767 ROWE: Get ready for the heavyweight 19 00:00:59,867 --> 00:01:00,000 championship of the universe. 20 00:01:00,000 --> 00:01:01,700 championship of the universe. 21 00:01:17,967 --> 00:01:21,100 2021, scientists detect 22 00:01:21,166 --> 00:01:24,100 a gigantic rumble deep in space, 23 00:01:24,166 --> 00:01:27,100 a tsunami of gravitational waves, 24 00:01:27,166 --> 00:01:30,000 giant ripples racing across the universe. 25 00:01:30,000 --> 00:01:30,667 giant ripples racing across the universe. 26 00:01:30,767 --> 00:01:33,800 MINGARELLI: Gravitational waves that big have to 27 00:01:33,867 --> 00:01:37,667 come from a giant, cataclysmic event. 28 00:01:37,667 --> 00:01:41,300 The universe is immense and full of very 29 00:01:41,367 --> 00:01:44,467 violent events that are happening every single day. 30 00:01:44,467 --> 00:01:47,700 The universe is a scary place. 31 00:01:47,767 --> 00:01:50,767 There is violence everywhere we look. 32 00:01:52,000 --> 00:01:55,100 ROWE: The growls and roars are clues about 33 00:01:55,166 --> 00:01:58,667 the ultimate cosmic brawl, 34 00:01:58,667 --> 00:02:00,000 the most violent event in the universe. 35 00:02:00,000 --> 00:02:01,867 the most violent event in the universe. 36 00:02:04,166 --> 00:02:07,900 But we don't know where they're coming from. 37 00:02:08,000 --> 00:02:09,600 SUTTER: Imagine a storm is coming 38 00:02:09,667 --> 00:02:10,667 in the middle of the night. 39 00:02:10,667 --> 00:02:12,000 You can't see the storm, 40 00:02:12,066 --> 00:02:15,266 you can't see the lightning, but you can hear that rumble of 41 00:02:15,367 --> 00:02:19,900 the distant thunder, and you know that it's coming. 42 00:02:20,000 --> 00:02:23,567 ROWE: This distant rumble of gravitational waves 43 00:02:23,667 --> 00:02:26,100 is like the footwork of heavyweights 44 00:02:26,166 --> 00:02:28,667 pounding the canvas of the boxing ring. 45 00:02:29,867 --> 00:02:30,000 The waves are caused by something massive 46 00:02:30,000 --> 00:02:32,667 The waves are caused by something massive 47 00:02:32,667 --> 00:02:34,266 throwing its weight around. 48 00:02:36,066 --> 00:02:39,767 It's not the first time we've detected gravitational waves. 49 00:02:43,000 --> 00:02:44,300 Our experiments have picked up 50 00:02:44,367 --> 00:02:47,266 the signal of two small stellar mass 51 00:02:47,266 --> 00:02:49,367 black holes colliding. 52 00:02:49,467 --> 00:02:54,100 These waves are high-pitched and ring like a boxing bell. 53 00:02:54,166 --> 00:02:58,367 The deep space growl is a much lower frequency, 54 00:02:58,367 --> 00:03:00,000 like the roar of a crowd. 55 00:03:00,000 --> 00:03:00,100 like the roar of a crowd. 56 00:03:00,166 --> 00:03:02,667 [crowd chanting] 57 00:03:02,667 --> 00:03:04,300 MINGARELLI: The difference in frequencies 58 00:03:04,367 --> 00:03:07,100 would be even more exaggerated than the difference 59 00:03:07,166 --> 00:03:10,567 between a sparrow chirping and the sound coming from 60 00:03:10,667 --> 00:03:12,400 a blue whale underwater. 61 00:03:12,467 --> 00:03:16,600 It would be orders of magnitude more different than that. 62 00:03:18,867 --> 00:03:21,400 ROWE: The low frequency of the deep space rumble 63 00:03:21,467 --> 00:03:24,200 tells us that the waves are colossal. 64 00:03:25,467 --> 00:03:28,367 MINGARELLI: Imagine throwing a stone in the water 65 00:03:28,467 --> 00:03:30,000 and watching the little ripples come out. 66 00:03:30,000 --> 00:03:30,300 and watching the little ripples come out. 67 00:03:30,367 --> 00:03:33,567 Now imagine throwing in a boulder a billion times 68 00:03:33,567 --> 00:03:34,667 more massive 69 00:03:34,767 --> 00:03:37,567 and watching the huge waves that come from that. 70 00:03:37,567 --> 00:03:39,800 Those are the waves that we're looking at. 71 00:03:41,400 --> 00:03:43,100 These are more difficult to detect, 72 00:03:43,166 --> 00:03:45,767 because the waves are so big. 73 00:03:45,867 --> 00:03:49,967 One of their wavelengths is about 15 light-years. 74 00:03:49,967 --> 00:03:51,767 You could wait for 15 years 75 00:03:51,867 --> 00:03:54,767 and only have one wavelength go by the Earth. 76 00:03:55,967 --> 00:03:58,700 ROWE: The waves are too big for an earthbound detector 77 00:03:58,767 --> 00:04:00,000 to pick up. 78 00:04:00,000 --> 00:04:00,300 to pick up. 79 00:04:00,367 --> 00:04:03,800 So, to search for the source of these giant waves, 80 00:04:03,867 --> 00:04:06,200 Chiara Mingarelli and her team 81 00:04:06,266 --> 00:04:10,300 use a detector already in space, 82 00:04:10,367 --> 00:04:12,066 something large enough to pick up 83 00:04:12,066 --> 00:04:14,867 these galactic heavyweights, 84 00:04:14,967 --> 00:04:18,800 spinning dead stars called pulsars. 85 00:04:18,867 --> 00:04:23,367 MINGARELLI: Our galaxy is awash with pulsars. 86 00:04:23,467 --> 00:04:26,100 Now, they're called pulsars because they pulsate 87 00:04:26,166 --> 00:04:29,166 very regularly -- they're like cosmic lighthouses. 88 00:04:29,266 --> 00:04:30,000 ROWE: The lighthouse beams are so regular, 89 00:04:30,000 --> 00:04:31,667 ROWE: The lighthouse beams are so regular, 90 00:04:31,767 --> 00:04:33,300 you can set your watch by them. 91 00:04:34,667 --> 00:04:38,266 But when a huge gravitational wave hits them, 92 00:04:38,367 --> 00:04:41,166 the timing gets knocked out of whack. 93 00:04:41,266 --> 00:04:44,867 PLAIT: That pulsar is going to basically rock back and forth 94 00:04:44,967 --> 00:04:46,867 and that's going to change the timing 95 00:04:46,867 --> 00:04:50,166 of the pulses that we measure from that object. 96 00:04:50,266 --> 00:04:53,867 ROWE: To identify the source of the gravitational waves, 97 00:04:53,867 --> 00:04:58,867 Chiara and her team measure the wobbles of 100 pulsars, 98 00:04:58,867 --> 00:05:00,000 spread across light-years of space. 99 00:05:00,000 --> 00:05:02,166 spread across light-years of space. 100 00:05:02,166 --> 00:05:06,166 MINGARELLI: It's like a tsunami, and the pulsars are 101 00:05:06,266 --> 00:05:08,600 like the buoys on the surface of the ocean. 102 00:05:08,667 --> 00:05:10,667 And as the tsunami passes by, 103 00:05:10,667 --> 00:05:12,567 we can watch all of them moving 104 00:05:12,567 --> 00:05:14,200 and shifting up and down. 105 00:05:14,266 --> 00:05:16,100 So our pulsar timing array 106 00:05:16,166 --> 00:05:18,667 is a gravitational wave warning system. 107 00:05:20,000 --> 00:05:22,266 ROWE: The pulsar array has identified 108 00:05:22,367 --> 00:05:25,600 the source of the tsunami of gravitational waves. 109 00:05:27,266 --> 00:05:29,367 The only thing we know of that can make these 110 00:05:29,467 --> 00:05:30,000 very long wavelength, [deep voice] very low pitch 111 00:05:30,000 --> 00:05:32,066 very long wavelength, [deep voice] very low pitch 112 00:05:32,066 --> 00:05:34,800 [normally] gravitational waves would be the collisions 113 00:05:34,867 --> 00:05:36,667 of supermassive black holes. 114 00:05:36,667 --> 00:05:38,767 MINGARELLI: They're massive, they're huge, 115 00:05:38,767 --> 00:05:40,967 and they know how to throw their weight around. 116 00:05:40,967 --> 00:05:44,367 Supermassive black hole binaries produce the loudest 117 00:05:44,367 --> 00:05:46,500 gravitational waves in the universe. 118 00:05:48,100 --> 00:05:50,667 ROWE: The gravitational wave signal revealed 119 00:05:50,767 --> 00:05:52,567 something extraordinary. 120 00:05:52,567 --> 00:05:55,166 MINGARELLI: It's not just gravitational waves coming 121 00:05:55,166 --> 00:05:57,867 from one black hole binary pair. 122 00:05:57,867 --> 00:05:59,400 It's actually from the cosmic 123 00:05:59,467 --> 00:06:00,000 population of supermassive black hole binaries. 124 00:06:00,000 --> 00:06:03,200 population of supermassive black hole binaries. 125 00:06:04,500 --> 00:06:06,800 ROWE: Chiara and her team think there may be 126 00:06:06,867 --> 00:06:11,266 tens of thousands of heavyweight bouts going on. 127 00:06:11,367 --> 00:06:14,867 Now, the scientists want to pick out the sound of one 128 00:06:14,967 --> 00:06:19,900 single collision between two supermassive black holes from 129 00:06:20,000 --> 00:06:21,667 the background roar. 130 00:06:24,166 --> 00:06:26,100 MINGARELLI: If we were to hear 131 00:06:26,166 --> 00:06:28,000 a supermassive black hole merger, 132 00:06:28,100 --> 00:06:30,000 it would sound like a very low frequency growl. 133 00:06:30,000 --> 00:06:30,700 it would sound like a very low frequency growl. 134 00:06:30,767 --> 00:06:33,400 This "ooooooh" 135 00:06:33,467 --> 00:06:36,200 that would last about 25 million years. 136 00:06:36,266 --> 00:06:39,100 ROWE: To date, we haven't witnessed two supermassive 137 00:06:39,166 --> 00:06:41,967 black holes trading blows in real time. 138 00:06:41,967 --> 00:06:45,367 But we have seen events leading up 139 00:06:45,367 --> 00:06:47,100 to the championship bout. 140 00:06:47,166 --> 00:06:50,000 We've watched galaxies merge. 141 00:06:50,100 --> 00:06:51,500 We've seen stars explode. 142 00:06:51,567 --> 00:06:54,567 We've seen so many violent events in the universe. 143 00:06:54,667 --> 00:06:56,367 But we haven't seen this one. 144 00:06:56,467 --> 00:06:58,667 It's odd if you think about it. 145 00:06:58,767 --> 00:07:00,000 We haven't seen the biggest one. 146 00:07:00,000 --> 00:07:00,500 We haven't seen the biggest one. 147 00:07:00,567 --> 00:07:03,967 We haven't seen mergers between supermassive black holes. 148 00:07:03,967 --> 00:07:06,567 ROWE: But that may be about to change. 149 00:07:08,600 --> 00:07:12,467 Chiara predicts there are 112 fighters who are 150 00:07:12,467 --> 00:07:15,567 pumped up and ready to enter the ring. 151 00:07:18,266 --> 00:07:19,600 MINGARELLI: In the next five years, 152 00:07:19,667 --> 00:07:22,300 we should be able to detect at least one 153 00:07:22,367 --> 00:07:24,166 supermassive black hole merger. 154 00:07:24,166 --> 00:07:30,000 ROWE: It'll be the most violent event in the cosmos. 155 00:07:30,000 --> 00:07:30,600 ROWE: It'll be the most violent event in the cosmos. 156 00:07:30,667 --> 00:07:32,700 Let's put that in context. 157 00:07:32,767 --> 00:07:37,166 We talk about how supernova are some of the most explosive, 158 00:07:37,266 --> 00:07:39,467 energetic things in our universe. 159 00:07:39,567 --> 00:07:42,567 Well, colliding supermassive black holes 160 00:07:42,567 --> 00:07:45,000 are a billion, billion, billion, 161 00:07:45,066 --> 00:07:48,800 billion times more energetic than a supernova. 162 00:07:48,867 --> 00:07:52,100 Think about all of the light being emitted by everything in 163 00:07:52,166 --> 00:07:55,367 the universe, every star, every galaxy. 164 00:07:55,467 --> 00:07:58,200 In one instant, two supermassive black holes 165 00:07:58,266 --> 00:08:00,000 colliding could release 100 million times that energy. 166 00:08:00,000 --> 00:08:02,567 colliding could release 100 million times that energy. 167 00:08:02,567 --> 00:08:05,967 Imagine being punched in the face by 168 00:08:05,967 --> 00:08:08,900 the biggest, baddest heavyweight of all time. 169 00:08:09,000 --> 00:08:11,767 Ouch. 170 00:08:11,767 --> 00:08:13,867 This is way bigger than that. 171 00:08:13,867 --> 00:08:17,567 ROWE: Where does all this energy come from? 172 00:08:17,567 --> 00:08:19,867 Surprisingly, it originates in 173 00:08:19,967 --> 00:08:22,667 the smallest atoms in the cosmos, 174 00:08:22,767 --> 00:08:26,200 in a story that dates back billions of years, 175 00:08:26,266 --> 00:08:29,667 all the way to the birth of the universe. 176 00:08:38,867 --> 00:08:40,000 ROWE: We're taking our seats for 177 00:08:40,100 --> 00:08:43,000 the most violent event in the universe, 178 00:08:43,100 --> 00:08:47,266 the collision of two supermassive black holes. 179 00:08:47,367 --> 00:08:49,100 We've never witnessed this cosmic 180 00:08:49,166 --> 00:08:50,800 heavyweight championship, 181 00:08:50,867 --> 00:08:54,367 but we can build up a picture of this epic fight by studying 182 00:08:54,367 --> 00:08:56,767 other weight classes with lighter fighters. 183 00:09:01,400 --> 00:09:03,079 2020 -- the earthbound gravitational wave detector, 184 00:09:03,079 --> 00:09:05,767 2020 -- the earthbound gravitational wave detector, 185 00:09:05,867 --> 00:09:07,367 LIGO, picks up 186 00:09:07,467 --> 00:09:10,367 the distinctive signal of a stellar mass 187 00:09:10,467 --> 00:09:11,700 black hole merger. 188 00:09:12,900 --> 00:09:17,867 What we saw was a black hole of 85 times the mass of our sun, 189 00:09:17,867 --> 00:09:21,166 and another black hole of 66 times the mass of our sun, 190 00:09:21,166 --> 00:09:25,166 smashing together to create a combined black hole. 191 00:09:25,166 --> 00:09:29,000 MINGARELLI: As someone who studies black hole mergers, 192 00:09:29,100 --> 00:09:31,000 this was a really exciting event. 193 00:09:31,066 --> 00:09:32,166 We're talking about 194 00:09:32,166 --> 00:09:33,079 the largest, the heaviest, the most massive 195 00:09:33,079 --> 00:09:34,667 the largest, the heaviest, the most massive 196 00:09:34,667 --> 00:09:37,400 black holes we have seen collide to date. 197 00:09:39,166 --> 00:09:41,266 ROWE: It may be the largest detection, 198 00:09:41,266 --> 00:09:43,266 but on a universal scale, 199 00:09:43,367 --> 00:09:46,867 it's still a small fry -- like lightweight boxers, 200 00:09:46,967 --> 00:09:49,700 the two black holes circle each other 201 00:09:49,767 --> 00:09:53,900 and emit low energy gravitational waves. 202 00:09:54,000 --> 00:09:56,467 This energy loss causes the black holes 203 00:09:56,567 --> 00:09:59,000 to spiral in together. 204 00:09:59,066 --> 00:10:02,900 Finally, they collide in a cosmos-shattering event, 205 00:10:04,667 --> 00:10:07,100 forming a single black hole 206 00:10:07,166 --> 00:10:11,266 and releasing a huge blast of gravitational waves. 207 00:10:11,367 --> 00:10:16,266 But when astronomers examine the single merged black hole, 208 00:10:16,266 --> 00:10:18,567 something doesn't add up. 209 00:10:18,667 --> 00:10:20,667 PONTZEN: If you take the combined mass of 210 00:10:20,767 --> 00:10:24,066 the two black holes, you get to 150 times 211 00:10:24,066 --> 00:10:25,467 the mass of our sun. 212 00:10:25,567 --> 00:10:28,800 But actually, the black hole that's left only has 213 00:10:28,867 --> 00:10:33,079 a mass of 142 times the mass of our sun. 214 00:10:33,079 --> 00:10:33,500 a mass of 142 times the mass of our sun. 215 00:10:33,567 --> 00:10:36,400 So the mass you have before the event does 216 00:10:36,467 --> 00:10:39,667 not equal the mass you have after the event. 217 00:10:39,667 --> 00:10:44,066 What happened to that missing eight solar masses? 218 00:10:44,066 --> 00:10:48,000 The way these black hole mergers work is very roughly 5 percent 219 00:10:48,100 --> 00:10:50,867 of the total mass of the system gets converted 220 00:10:50,967 --> 00:10:52,367 into energy. 221 00:10:52,367 --> 00:10:56,800 ROWE: It all comes down to E equals MC squared. 222 00:10:58,000 --> 00:11:00,467 This is that beautiful equation that Einstein 223 00:11:00,567 --> 00:11:02,967 told us -- E equals MC squared. 224 00:11:02,967 --> 00:11:03,079 E is the energy, and M is the mass. 225 00:11:03,079 --> 00:11:06,000 E is the energy, and M is the mass. 226 00:11:06,066 --> 00:11:09,367 Einstein taught us that mass and energy are related. 227 00:11:09,367 --> 00:11:13,467 In fact, much of what we call mass is actually energy. 228 00:11:13,567 --> 00:11:16,567 ROWE: In this case, the violence of the collision 229 00:11:16,567 --> 00:11:21,266 transforms 18,000 trillion trillion tons 230 00:11:21,367 --> 00:11:25,367 of matter into an explosion of gravitational waves. 231 00:11:25,467 --> 00:11:28,166 SUTTER: In just a fraction of a second, 232 00:11:28,266 --> 00:11:33,079 eight suns worth of matter is converted into pure 233 00:11:33,079 --> 00:11:33,867 eight suns worth of matter is converted into pure 234 00:11:33,967 --> 00:11:35,867 unadulterated energy. 235 00:11:35,967 --> 00:11:38,967 The amount of energy released was so great, that if you add 236 00:11:38,967 --> 00:11:41,900 up all the energy of all the stars burning in 237 00:11:42,000 --> 00:11:43,667 the universe, 238 00:11:43,667 --> 00:11:45,667 it was bigger than that. 239 00:11:45,667 --> 00:11:50,767 ROWE: This event was a collision between relative lightweights, 240 00:11:50,767 --> 00:11:54,000 two stellar mass black holes. 241 00:11:56,100 --> 00:11:58,400 To understand heavyweight bouts, 242 00:11:58,467 --> 00:12:03,079 we need to scale up to supermassive black holes. 243 00:12:03,079 --> 00:12:03,567 we need to scale up to supermassive black holes. 244 00:12:06,100 --> 00:12:07,900 In the universe of sports, 245 00:12:08,000 --> 00:12:11,500 supermassive black holes are the heavyweight contenders. 246 00:12:11,567 --> 00:12:14,767 With these big black holes, size matters. 247 00:12:14,867 --> 00:12:16,300 The bigger the better. 248 00:12:16,367 --> 00:12:18,467 More mass means more energy, 249 00:12:18,467 --> 00:12:21,266 which means more destructive power. 250 00:12:21,367 --> 00:12:23,967 ROWE: We don't need to look too far to find 251 00:12:23,967 --> 00:12:26,000 this devastating muscle. 252 00:12:26,066 --> 00:12:28,967 This is M87 star, 253 00:12:28,967 --> 00:12:32,300 one of the largest supermassive black holes 254 00:12:32,367 --> 00:12:33,079 in our cosmic zip code. 255 00:12:33,079 --> 00:12:33,667 in our cosmic zip code. 256 00:12:34,967 --> 00:12:37,467 M87 star is huge. 257 00:12:37,467 --> 00:12:40,467 It weighs about six billion solar masses, 258 00:12:40,567 --> 00:12:42,000 about six billion suns, 259 00:12:42,066 --> 00:12:44,467 and it's the size of our solar system. 260 00:12:44,567 --> 00:12:48,166 ROWE: A collision between two 6-billion solar mass 261 00:12:48,166 --> 00:12:51,300 supermassive black holes would release around five 262 00:12:51,367 --> 00:12:55,400 times 10 to the power of 56 joules. 263 00:12:55,467 --> 00:12:59,300 So what's that mean in real world terms? 264 00:12:59,367 --> 00:13:02,767 It's hard to use words to express how much energy this is, 265 00:13:02,767 --> 00:13:03,079 and the numbers are so huge, they are almost meaningless. 266 00:13:03,079 --> 00:13:05,500 and the numbers are so huge, they are almost meaningless. 267 00:13:05,567 --> 00:13:07,967 The only way I can really explain this is... 268 00:13:07,967 --> 00:13:09,700 [exaggerated scream] 269 00:13:11,767 --> 00:13:14,467 In physics, we have these comparisons 270 00:13:14,467 --> 00:13:15,700 so we can get a mental picture, 271 00:13:15,767 --> 00:13:18,500 but for something like this, there is no mental picture. 272 00:13:18,567 --> 00:13:21,100 That is so freaking big. 273 00:13:24,166 --> 00:13:26,266 ROWE: So where does this destructive 274 00:13:26,266 --> 00:13:29,100 mass and energy come from? 275 00:13:32,367 --> 00:13:33,079 It starts with the simplest ingredient -- 276 00:13:33,079 --> 00:13:35,467 It starts with the simplest ingredient -- 277 00:13:35,567 --> 00:13:37,000 hydrogen. 278 00:13:39,667 --> 00:13:44,166 Hydrogen is the basic building block of the universe. 279 00:13:44,266 --> 00:13:49,667 Each atom is tiny, but it contains a lot of energy. 280 00:13:49,767 --> 00:13:52,667 Hydrogen atoms contain a huge amount of energy, 281 00:13:52,767 --> 00:13:54,266 just like all matter does. 282 00:13:54,367 --> 00:13:56,000 And if it's unlocked in 283 00:13:56,066 --> 00:13:58,867 a certain way, there can be huge explosions. 284 00:14:01,767 --> 00:14:03,079 I mean, you take the mass contained simply in my hand, 285 00:14:03,079 --> 00:14:04,767 I mean, you take the mass contained simply in my hand, 286 00:14:04,867 --> 00:14:07,000 and you could blow up pretty much the entire Earth. 287 00:14:07,066 --> 00:14:11,166 ROWE: Matter has energy because it formed from 288 00:14:11,266 --> 00:14:13,667 energy in the early moments of the universe. 289 00:14:14,767 --> 00:14:17,467 In many ways, atoms are reservoirs 290 00:14:17,567 --> 00:14:20,700 of stored energy from the Big Bang. 291 00:14:20,767 --> 00:14:24,200 ROWE: 13.8 billion years ago, 292 00:14:24,266 --> 00:14:26,667 the universe ignites 293 00:14:26,767 --> 00:14:30,367 in a super hot ball of intense energy. 294 00:14:30,467 --> 00:14:33,079 Right after the Big Bang, there's a tremendous 295 00:14:33,079 --> 00:14:33,266 Right after the Big Bang, there's a tremendous 296 00:14:33,266 --> 00:14:34,700 amount of energy -- so much energy, 297 00:14:34,767 --> 00:14:36,900 in fact, that normal atoms can't exist. 298 00:14:39,367 --> 00:14:42,367 As that early energy starts to cool, 299 00:14:42,467 --> 00:14:45,266 it can start to form primitive matter. 300 00:14:47,867 --> 00:14:51,066 ROWE: The universe takes that first matter and energy 301 00:14:51,066 --> 00:14:53,367 in the form of hydrogen atoms 302 00:14:53,467 --> 00:14:55,867 and starts the process of creating 303 00:14:55,867 --> 00:14:58,266 a supermassive black hole. 304 00:14:58,266 --> 00:15:01,600 Step one -- build giant stars. 305 00:15:01,667 --> 00:15:03,079 So gravity brings together gas, dust, hydrogen, 306 00:15:03,079 --> 00:15:06,367 So gravity brings together gas, dust, hydrogen, 307 00:15:06,467 --> 00:15:07,467 all of that stuff, 308 00:15:07,567 --> 00:15:09,700 and as the clouds become more dense, 309 00:15:09,767 --> 00:15:12,500 they attract even more material. 310 00:15:12,567 --> 00:15:16,467 NANCE: As they spin, they get hotter and hotter, and as that 311 00:15:16,467 --> 00:15:18,400 temperature and pressure increase, 312 00:15:18,467 --> 00:15:21,867 finally, it ignites nuclear fusion within the core 313 00:15:21,867 --> 00:15:23,700 and creates an actual star. 314 00:15:26,200 --> 00:15:29,967 ROWE: These huge stars are like cosmic rock stars. 315 00:15:29,967 --> 00:15:32,200 They live fast and die young. 316 00:15:33,767 --> 00:15:38,567 When they die, they flame out in a huge explosion, 317 00:15:38,667 --> 00:15:40,467 a supernova. 318 00:15:40,567 --> 00:15:44,867 SUTTER: The entire star turns itself inside out 319 00:15:44,867 --> 00:15:48,166 and releases a shockwave going a good 320 00:15:48,166 --> 00:15:52,100 fraction of the speed of light and releases enough energy to 321 00:15:52,166 --> 00:15:54,100 just obliterate you. 322 00:15:54,166 --> 00:15:57,367 ROWE: If the dying star is more 323 00:15:57,367 --> 00:15:59,567 than 15 stellar masses, 324 00:15:59,667 --> 00:16:02,867 its core collapses into a black hole. 325 00:16:02,867 --> 00:16:03,079 It's kind of astounding what the universe is doing. 326 00:16:03,079 --> 00:16:06,100 It's kind of astounding what the universe is doing. 327 00:16:06,166 --> 00:16:09,166 It's taking incredibly simple things, like hydrogen atoms, 328 00:16:09,166 --> 00:16:11,667 and using gravity to ultimately 329 00:16:11,667 --> 00:16:13,400 bring all this stuff together and make things 330 00:16:13,467 --> 00:16:15,567 like black holes. 331 00:16:15,667 --> 00:16:18,867 I find it quite beautiful how our whole 332 00:16:18,867 --> 00:16:21,400 cosmic history is the story of 333 00:16:21,467 --> 00:16:24,600 little things coming together into bigger things. 334 00:16:24,667 --> 00:16:27,467 ROWE: But these stellar mass black holes are tiny 335 00:16:27,567 --> 00:16:31,066 flyweights -- to step up to the heavyweight division, 336 00:16:31,066 --> 00:16:33,079 they have to grow billions of times more massive. 337 00:16:33,079 --> 00:16:35,000 they have to grow billions of times more massive. 338 00:16:35,066 --> 00:16:36,900 But how? 339 00:16:37,000 --> 00:16:39,700 How do black holes become supermassive? 340 00:16:40,867 --> 00:16:43,100 This is the age-old question. 341 00:16:43,166 --> 00:16:44,800 We're not really sure. 342 00:16:44,867 --> 00:16:47,700 TEGMARK: The current state of our understanding 343 00:16:47,767 --> 00:16:50,767 of how black holes become supermassive is like, 344 00:16:50,767 --> 00:16:52,467 uhhh, we're confused. 345 00:16:52,467 --> 00:16:53,867 We really don't know. 346 00:16:53,967 --> 00:16:57,467 We still don't know exactly how they become so big. 347 00:16:59,400 --> 00:17:00,667 ROWE: But we do know that 348 00:17:00,767 --> 00:17:03,079 the process involves ultraviolence, 349 00:17:03,079 --> 00:17:03,500 the process involves ultraviolence, 350 00:17:03,567 --> 00:17:05,367 death, and destruction. 351 00:17:14,166 --> 00:17:18,300 ROWE: How do supermassive black holes grow so big? 352 00:17:18,367 --> 00:17:22,200 That's a question that continues to baffle scientists. 353 00:17:22,266 --> 00:17:26,300 In June of 2018, we spotted a clue, 354 00:17:26,367 --> 00:17:28,600 an enormous flash of light. 355 00:17:28,667 --> 00:17:32,066 AT2018cow, 356 00:17:32,066 --> 00:17:33,367 nicknamed "the cow," 357 00:17:33,467 --> 00:17:36,900 was the brightest explosion ever recorded. 358 00:17:37,000 --> 00:17:38,093 A huge amount of energy was released, 359 00:17:38,093 --> 00:17:39,100 A huge amount of energy was released, 360 00:17:39,166 --> 00:17:41,000 and then all of a sudden, everything was gone. 361 00:17:42,266 --> 00:17:45,166 This explosion was incredibly violent. 362 00:17:45,166 --> 00:17:46,100 At first, it was thought 363 00:17:46,166 --> 00:17:48,400 to just be a supernova, a flash of light. 364 00:17:48,467 --> 00:17:50,000 But over time, it became clear 365 00:17:50,066 --> 00:17:52,467 that this was something much more powerful. 366 00:17:52,467 --> 00:17:55,767 It was too bright, basically, to be a supernova. 367 00:17:55,767 --> 00:17:59,166 It was extremely bright, and it didn't fit into 368 00:17:59,166 --> 00:18:01,300 any of our theoretical understandings 369 00:18:01,367 --> 00:18:03,567 of how bright supernova should be. 370 00:18:04,600 --> 00:18:07,567 ROWE: One explanation is that the light may have come from 371 00:18:07,567 --> 00:18:08,093 a black hole feeding 372 00:18:08,093 --> 00:18:09,300 a black hole feeding 373 00:18:09,367 --> 00:18:13,767 on a small white dwarf star weighing less than the sun. 374 00:18:13,767 --> 00:18:18,100 What really seemed to fit that model was a star getting 375 00:18:18,166 --> 00:18:19,367 too close to a black hole 376 00:18:19,367 --> 00:18:20,700 and getting ripped apart, and then 377 00:18:20,767 --> 00:18:22,567 everything going right down the black hole. 378 00:18:24,166 --> 00:18:27,367 PLAIT: A black hole gains mass every time it eats something. 379 00:18:27,467 --> 00:18:28,667 That's how they grow. 380 00:18:28,667 --> 00:18:31,567 Whether it's a gas cloud or a star or another black hole, 381 00:18:31,567 --> 00:18:34,800 once it gains that mass, it's gained that mass. 382 00:18:37,367 --> 00:18:38,093 OLUSEYI: People often ask me, what happens to 383 00:18:38,093 --> 00:18:39,266 OLUSEYI: People often ask me, what happens to 384 00:18:39,266 --> 00:18:41,100 the mass that falls into a black hole? 385 00:18:41,166 --> 00:18:42,667 Does it go to another dimension? 386 00:18:42,767 --> 00:18:45,200 And the answer is no, it's still there. 387 00:18:45,266 --> 00:18:50,000 It's inside the black hole -- they get bigger, they grow. 388 00:18:50,066 --> 00:18:53,667 ROWE: Could this be how weak flyweight black holes 389 00:18:53,767 --> 00:18:55,700 turn into mean and powerful 390 00:18:55,767 --> 00:18:57,600 supermassive heavyweights? 391 00:18:57,667 --> 00:18:59,600 The star is like protein, 392 00:18:59,667 --> 00:19:04,166 and the black hole is like a boxer. 393 00:19:04,166 --> 00:19:07,000 And so the more protein they get, the more stars 394 00:19:07,066 --> 00:19:08,093 they consume, the stronger they get, 395 00:19:08,093 --> 00:19:08,567 they consume, the stronger they get, 396 00:19:08,667 --> 00:19:10,266 the more destructive they can be. 397 00:19:13,700 --> 00:19:15,200 ROWE: But there's a problem with 398 00:19:15,266 --> 00:19:16,867 the training program explanation. 399 00:19:18,400 --> 00:19:20,467 Eating small stars 400 00:19:20,567 --> 00:19:24,166 one at a time just doesn't add enough mass fast enough 401 00:19:24,266 --> 00:19:26,266 to grow the supermassive black holes 402 00:19:26,266 --> 00:19:27,600 that we see today. 403 00:19:27,667 --> 00:19:32,500 That's like boxers eating just one egg per day. 404 00:19:32,567 --> 00:19:37,600 Like them, black holes need much bigger meals, 405 00:19:37,667 --> 00:19:38,093 and in 2020, we detected one, 406 00:19:38,093 --> 00:19:41,600 and in 2020, we detected one, 407 00:19:41,667 --> 00:19:44,767 a sudden burst of gravitational waves from 408 00:19:44,767 --> 00:19:46,700 a black hole gorging on 409 00:19:46,767 --> 00:19:49,166 the remains of a dead star 410 00:19:49,166 --> 00:19:53,166 called a neutron star. 411 00:19:54,166 --> 00:19:58,400 For scientists, January 2020 was exciting, because it was 412 00:19:58,467 --> 00:20:02,400 the first time LIGO observed the very first black hole 413 00:20:02,467 --> 00:20:04,266 neutron star merger. 414 00:20:04,266 --> 00:20:07,100 ROWE: Neutron stars may be small, 415 00:20:07,166 --> 00:20:08,093 but they are inconceivably dense. 416 00:20:08,093 --> 00:20:10,467 but they are inconceivably dense. 417 00:20:10,567 --> 00:20:12,266 Now, you want to talk about an enormous amount of mass, 418 00:20:12,367 --> 00:20:13,467 let's talk about a neutron star. 419 00:20:13,567 --> 00:20:15,166 That's -- that's one heck of a snack. 420 00:20:16,266 --> 00:20:20,266 ROWE: The black hole swallowed the neutron star in one gulp. 421 00:20:21,567 --> 00:20:25,367 So this black hole ate a whole neutron star, 422 00:20:25,467 --> 00:20:28,867 which means it gained just over 10 percent of its entire 423 00:20:28,967 --> 00:20:31,367 body weight in one shot. 424 00:20:31,467 --> 00:20:34,100 ROWE: 10 percent doesn't sound like a lot, 425 00:20:34,166 --> 00:20:36,100 but then we detected another 426 00:20:36,166 --> 00:20:38,093 black hole swallowing a neutron star just 10 days later, 427 00:20:38,093 --> 00:20:40,166 black hole swallowing a neutron star just 10 days later, 428 00:20:40,166 --> 00:20:44,100 suggesting that there are lots of black holes bulking up 429 00:20:44,166 --> 00:20:45,266 across the universe. 430 00:20:45,367 --> 00:20:48,467 But even with this extreme weight gain, 431 00:20:48,467 --> 00:20:52,400 it's probably not enough to get supermassive. 432 00:20:52,467 --> 00:20:54,367 They need to eat even more. 433 00:20:55,567 --> 00:20:57,700 If you're a black hole, and you want to get bigger, 434 00:20:57,767 --> 00:21:01,266 your best bet is to merge with another black hole. 435 00:21:01,367 --> 00:21:03,467 ROWE: But there's a catch. 436 00:21:03,467 --> 00:21:08,093 So if you're a flyweight black hole, and you try to eat all of 437 00:21:08,093 --> 00:21:09,500 So if you're a flyweight black hole, and you try to eat all of 438 00:21:09,567 --> 00:21:11,567 the other flyweight black holes, 439 00:21:11,667 --> 00:21:15,066 there's just not enough time in the history of the universe 440 00:21:15,066 --> 00:21:17,800 for you to become a supermassive black hole. 441 00:21:17,867 --> 00:21:20,266 But you can make it to middleweight. 442 00:21:20,367 --> 00:21:24,400 ROWE: So exactly how supermassive black holes 443 00:21:24,467 --> 00:21:27,867 grow so large remains an open question. 444 00:21:27,967 --> 00:21:31,367 We do know that the process started in the very early 445 00:21:31,467 --> 00:21:33,100 universe with a journey 446 00:21:33,166 --> 00:21:35,166 from the lightest element to the most 447 00:21:35,266 --> 00:21:38,093 intimidating object in the cosmos. 448 00:21:38,093 --> 00:21:38,367 intimidating object in the cosmos. 449 00:21:38,367 --> 00:21:41,166 It's so interesting how the cosmos can take something as 450 00:21:41,166 --> 00:21:44,867 simple as a hydrogen atom and build stellar mass 451 00:21:44,867 --> 00:21:48,700 black holes and intermediate mass black holes 452 00:21:48,767 --> 00:21:51,166 and even supermassive black holes out of 453 00:21:51,266 --> 00:21:55,467 these really densely compressed hydrogen atoms. 454 00:21:55,567 --> 00:21:58,166 It's really a wonder. 455 00:21:58,266 --> 00:22:01,166 ROWE: Now, 13.8 billion years 456 00:22:01,166 --> 00:22:04,367 after the Big Bang, supermassive black holes 457 00:22:04,367 --> 00:22:06,800 feed and flex their muscles, 458 00:22:06,867 --> 00:22:08,093 ready to fight for the heavyweight 459 00:22:08,093 --> 00:22:08,767 ready to fight for the heavyweight 460 00:22:08,767 --> 00:22:10,667 championship of the universe. 461 00:22:10,667 --> 00:22:13,967 These supermassive black holes have been bulking up 462 00:22:13,967 --> 00:22:15,767 since the age of the universe. 463 00:22:15,867 --> 00:22:17,800 SUTTER: These black holes have been 464 00:22:17,867 --> 00:22:19,667 getting ready for the fight. 465 00:22:19,767 --> 00:22:21,166 They have been bulking up. 466 00:22:21,266 --> 00:22:24,967 They have been eating entire stars as snacks 467 00:22:24,967 --> 00:22:27,100 to get the masks they need. 468 00:22:27,166 --> 00:22:29,000 So they are ready to rumble. 469 00:22:30,000 --> 00:22:32,266 ROWE: It's not the rumble in the jungle. 470 00:22:32,367 --> 00:22:36,266 This is the battle to be the boss of the cosmos. 471 00:22:36,367 --> 00:22:38,093 Supermassive black hole versus supermassive 472 00:22:38,093 --> 00:22:40,400 Supermassive black hole versus supermassive 473 00:22:40,467 --> 00:22:44,567 black hole, fought in the grandest arena. 474 00:22:44,567 --> 00:22:48,567 The fighter's entourage, their host galaxies, 475 00:22:48,667 --> 00:22:50,600 escort them to the ring. 476 00:22:50,667 --> 00:22:52,867 But even this journey is violent, 477 00:22:52,967 --> 00:22:56,867 triggering starbursts, jets, and carnage. 478 00:23:05,767 --> 00:23:08,467 ROWE: It's the build up before the heavyweight fight 479 00:23:08,567 --> 00:23:10,166 of the cosmos. 480 00:23:10,266 --> 00:23:13,967 The fighters' entourages, their galaxies, carry 481 00:23:14,033 --> 00:23:16,500 their supermassive black holes to the ring. 482 00:23:17,767 --> 00:23:19,734 Things are about to get nasty. 483 00:23:20,867 --> 00:23:23,300 Galaxies can look calm and serene, 484 00:23:23,367 --> 00:23:25,767 but they can get into pretty big scraps. 485 00:23:28,266 --> 00:23:29,378 There's a lot of them that are totally 486 00:23:29,378 --> 00:23:30,166 There's a lot of them that are totally 487 00:23:30,233 --> 00:23:33,934 messed up and are clearly merging with each other. 488 00:23:37,066 --> 00:23:40,734 ROWE: When galaxies fight, their gravity pulls on each 489 00:23:40,734 --> 00:23:43,767 other, twisting and distorting their structures. 490 00:23:43,834 --> 00:23:49,100 The galaxy will be warped and morphed into different ways 491 00:23:49,166 --> 00:23:52,767 that we can only imagine how twisted it would be. 492 00:23:54,467 --> 00:23:56,467 ROWE: This violent cosmic tango brings 493 00:23:56,567 --> 00:23:59,378 the two supermassive black holes together. 494 00:23:59,378 --> 00:23:59,400 the two supermassive black holes together. 495 00:23:59,467 --> 00:24:02,100 TREMBLAY: It's elegant, it's beautiful. 496 00:24:02,166 --> 00:24:06,667 It's this billion-year choreographed dance 497 00:24:06,734 --> 00:24:09,300 that is entirely conducted by gravity. 498 00:24:12,867 --> 00:24:15,934 ROWE: The two heavyweight fighters approach each other. 499 00:24:16,000 --> 00:24:18,066 Their feet beat out a rhythm on the canvas, 500 00:24:18,133 --> 00:24:22,400 just like circling black holes release low energy 501 00:24:22,467 --> 00:24:24,000 gravitational waves. 502 00:24:25,100 --> 00:24:29,166 You have these giant beasts that are stalking 503 00:24:29,266 --> 00:24:29,378 around each other, and as they do, 504 00:24:29,378 --> 00:24:31,266 around each other, and as they do, 505 00:24:31,367 --> 00:24:34,133 they create these gravitational waves. 506 00:24:36,367 --> 00:24:39,100 ROWE: June 2021. 507 00:24:39,166 --> 00:24:42,066 Astronomers photograph a galactic collision 508 00:24:42,133 --> 00:24:46,467 and witness a spectacular pre-fight fireworks show. 509 00:24:46,467 --> 00:24:49,367 One of the amazing things that can happen 510 00:24:49,367 --> 00:24:51,266 when galaxies collide is they can create 511 00:24:51,266 --> 00:24:53,400 tremendous starbursts. 512 00:24:53,467 --> 00:24:56,133 There is a big inrush as all of 513 00:24:56,133 --> 00:24:59,378 the gas follows that gravity -- as the gas gets hotter 514 00:24:59,378 --> 00:25:00,100 the gas follows that gravity -- as the gas gets hotter 515 00:25:00,100 --> 00:25:03,166 and denser, it creates shockwaves, 516 00:25:03,266 --> 00:25:05,867 and each shockwave actually creates a new generation of 517 00:25:05,967 --> 00:25:09,233 stars going out around the core of the galaxy. 518 00:25:09,233 --> 00:25:13,066 ROWE: The sudden starburst lights up the merging galaxies. 519 00:25:13,133 --> 00:25:16,467 The inrushing gas also fuels the prize fighters, 520 00:25:17,467 --> 00:25:20,133 the supermassive black holes spiraling 521 00:25:20,133 --> 00:25:24,400 towards the merging galactic center. 522 00:25:24,467 --> 00:25:28,000 PONTZEN: If there's a big supermassive black hole, 523 00:25:28,066 --> 00:25:29,378 it suddenly finds it surrounded by loads of gas 524 00:25:29,378 --> 00:25:31,467 it suddenly finds it surrounded by loads of gas 525 00:25:31,467 --> 00:25:34,266 and other material it can eat. 526 00:25:34,367 --> 00:25:37,066 It goes on a kind of feeding frenzy. 527 00:25:37,133 --> 00:25:39,467 If you're a hungry supermassive black hole, 528 00:25:39,567 --> 00:25:42,667 then this is your lunchtime buffet. 529 00:25:42,767 --> 00:25:46,767 ROWE: Not all the gas falls into the supermassive black hole. 530 00:25:46,834 --> 00:25:50,967 Other parts of the matter actually gets caught up 531 00:25:51,033 --> 00:25:52,867 in what we call an accretion disk 532 00:25:52,967 --> 00:25:56,367 rotating around the outside of the black hole. 533 00:25:56,467 --> 00:25:59,378 ROWE: This bright vortex spins around the supermassive 534 00:25:59,378 --> 00:25:59,500 ROWE: This bright vortex spins around the supermassive 535 00:25:59,567 --> 00:26:03,500 black hole at over two million miles an hour. 536 00:26:03,567 --> 00:26:06,867 The material in the disk rubs against itself, 537 00:26:06,967 --> 00:26:09,000 creating friction. 538 00:26:09,066 --> 00:26:12,867 Friction generates heat -- if I rub my hands together, 539 00:26:12,934 --> 00:26:14,400 they get a little bit warm. 540 00:26:14,467 --> 00:26:18,500 If I rub my hands together at hundreds of thousands of 541 00:26:18,567 --> 00:26:21,734 miles per hour, it's gonna get very, very, very warm. 542 00:26:24,066 --> 00:26:26,000 ROWE: The accretion disk heats up, 543 00:26:26,066 --> 00:26:28,467 blasting out intense light. 544 00:26:30,367 --> 00:26:31,467 In 2020, 545 00:26:31,500 --> 00:26:35,133 NASA's Hubble space telescope saw two fueled-up 546 00:26:35,133 --> 00:26:38,500 supermassive black holes lighting up for the fight. 547 00:26:40,266 --> 00:26:42,100 We call them quasars. 548 00:26:43,767 --> 00:26:49,066 Quasars are a subclass of very bright black holes 549 00:26:49,133 --> 00:26:51,300 that are emitting huge amounts of power. 550 00:26:51,367 --> 00:26:54,467 So these can be seen at the far reaches of the universe. 551 00:26:57,133 --> 00:26:59,378 TREMBLAY: Black holes, these so-called dark things, 552 00:26:59,378 --> 00:26:59,667 TREMBLAY: Black holes, these so-called dark things, 553 00:26:59,767 --> 00:27:01,934 when they're growing at a very high rate 554 00:27:02,000 --> 00:27:04,867 are some of the brightest lights in the universe. 555 00:27:05,867 --> 00:27:09,100 ROWE: To date, we've detected over 100 pairs 556 00:27:09,166 --> 00:27:13,133 of quasars in the cores of merging galaxies. 557 00:27:13,133 --> 00:27:17,300 We think they will all eventually collide, 558 00:27:17,367 --> 00:27:21,367 but before they do, they'll put on a spectacular 559 00:27:21,467 --> 00:27:24,266 and lethal light show. 560 00:27:24,266 --> 00:27:27,667 A common theme in science fiction 561 00:27:27,767 --> 00:27:29,378 are different kind of jets of energy or beams 562 00:27:29,378 --> 00:27:30,133 are different kind of jets of energy or beams 563 00:27:30,133 --> 00:27:32,500 that people shoot out of their eyes or their hands. 564 00:27:32,567 --> 00:27:35,934 Well, supermassive black holes do that, too. 565 00:27:36,000 --> 00:27:38,567 ROWE: Firing out relativistic jets. 566 00:27:39,867 --> 00:27:43,467 When those jets fire up, 567 00:27:43,567 --> 00:27:46,667 that's when you're talking about superstar, really, 568 00:27:46,734 --> 00:27:49,767 really bright lights, and at this point, the galaxy is lit up 569 00:27:49,867 --> 00:27:51,000 and ready to go. 570 00:27:52,834 --> 00:27:57,033 These are the spotlight's on Madison Square Garden. 571 00:27:57,100 --> 00:27:59,378 This is telling you that the event is going down. 572 00:27:59,378 --> 00:28:00,166 This is telling you that the event is going down. 573 00:28:00,266 --> 00:28:01,967 [crowd cheering] 574 00:28:02,033 --> 00:28:04,467 A single supermassive black hole jet 575 00:28:04,567 --> 00:28:07,467 will produce more energy in a second 576 00:28:07,467 --> 00:28:09,100 than the sun will produce in 577 00:28:09,166 --> 00:28:11,600 its entire 10-billion-year lifetime. 578 00:28:16,567 --> 00:28:20,033 Imagine a laser of radiation that 579 00:28:20,100 --> 00:28:22,266 is light-years in length and across. 580 00:28:22,367 --> 00:28:23,667 That's what we're talking about. 581 00:28:23,767 --> 00:28:26,266 This thing would fry a planet. 582 00:28:27,367 --> 00:28:29,378 ROWE: This is no pre-fight hype. 583 00:28:29,378 --> 00:28:30,133 ROWE: This is no pre-fight hype. 584 00:28:30,133 --> 00:28:34,834 In February 2020, we saw the impact of a jet. 585 00:28:36,100 --> 00:28:38,000 TREMBLAY: So in the Ophiuchus galaxy cluster, 586 00:28:38,066 --> 00:28:41,233 there's an enormous void that is 15 times wider than 587 00:28:41,233 --> 00:28:42,300 the Milky Way galaxy. 588 00:28:42,367 --> 00:28:44,500 And this has all been sculpted, carved, 589 00:28:44,567 --> 00:28:48,467 by jets from a supermassive black hole. 590 00:28:48,467 --> 00:28:50,467 STRAUGHN: It's like this scar on the universe. 591 00:28:50,467 --> 00:28:52,300 It's a million light-years across. 592 00:28:52,367 --> 00:28:54,467 It's huge. 593 00:28:54,467 --> 00:28:57,467 ROWE: Scientists calculate the impact of the jet hitting 594 00:28:57,567 --> 00:28:59,378 the cluster was equivalent to 595 00:28:59,378 --> 00:28:59,834 the cluster was equivalent to 596 00:28:59,834 --> 00:29:05,166 a 20-billion-billion megaton TNT explosion every 1,000th of 597 00:29:05,233 --> 00:29:09,066 a second for 240 million years. 598 00:29:12,500 --> 00:29:15,367 The relativistic jets' immense power may be 599 00:29:15,367 --> 00:29:16,367 a showstopper. 600 00:29:16,467 --> 00:29:18,867 But when it's time to land the killer punch, 601 00:29:18,967 --> 00:29:23,934 supermassive black holes draw on an even more powerful force, 602 00:29:24,000 --> 00:29:25,500 gravity. 603 00:29:25,567 --> 00:29:27,667 STRAUGHN: Jets are very powerful, but really 604 00:29:27,767 --> 00:29:29,378 only on a relatively small scale. 605 00:29:29,378 --> 00:29:29,767 only on a relatively small scale. 606 00:29:29,834 --> 00:29:32,233 When you're talking about cosmic scale, 607 00:29:32,233 --> 00:29:33,867 gravity always wins. 608 00:29:33,934 --> 00:29:36,734 Nothing is as powerful as gravity. 609 00:29:36,734 --> 00:29:38,467 ROWE: The immense gravity of the circling 610 00:29:38,567 --> 00:29:42,600 supermassive black holes drags them ever closer, 611 00:29:42,667 --> 00:29:46,066 but will it ultimately bring them together 612 00:29:46,133 --> 00:29:47,934 or blast them apart? 613 00:29:56,567 --> 00:29:58,567 ROWE: Across the universe, 614 00:29:58,667 --> 00:30:02,033 supermassive black holes duke it out 615 00:30:02,100 --> 00:30:06,567 in the cosmos's version of heavyweight super fights. 616 00:30:06,667 --> 00:30:11,467 Supermassive black holes are merging around us all the time. 617 00:30:11,467 --> 00:30:13,934 It's only our ability to detect them 618 00:30:14,000 --> 00:30:15,867 that's preventing us from seeing them. 619 00:30:18,166 --> 00:30:19,687 ROWE: Scientists have identified at least a dozen 620 00:30:19,687 --> 00:30:20,667 ROWE: Scientists have identified at least a dozen 621 00:30:20,767 --> 00:30:24,567 pairs of supermassive black holes circling each other. 622 00:30:25,934 --> 00:30:28,266 We have some hints of some galaxies 623 00:30:28,367 --> 00:30:29,667 where we think it might happen, 624 00:30:29,767 --> 00:30:32,567 where we see two glowing black holes that are getting 625 00:30:32,567 --> 00:30:33,767 very close. 626 00:30:34,934 --> 00:30:37,567 ROWE: But not all these matches will end with a knockout. 627 00:30:38,834 --> 00:30:41,467 Black hole collisions happen all the time. 628 00:30:41,467 --> 00:30:44,166 But they don't always go according to plan. 629 00:30:44,233 --> 00:30:45,867 When black holes come together, 630 00:30:45,934 --> 00:30:48,333 really strange things can happen. 631 00:30:49,667 --> 00:30:49,687 ROWE: The Hubble space telescope spots something strange in 632 00:30:49,687 --> 00:30:53,967 ROWE: The Hubble space telescope spots something strange in 633 00:30:54,033 --> 00:30:58,667 a distant galaxy called 3C186. 634 00:30:58,767 --> 00:31:02,667 It's a quasar, an active supermassive black hole. 635 00:31:05,066 --> 00:31:06,367 But it's in the wrong place. 636 00:31:07,667 --> 00:31:11,033 In nearly every galaxy we see, the supermassive black hole 637 00:31:11,100 --> 00:31:12,967 sits right at the center, and that makes sense. 638 00:31:14,066 --> 00:31:15,166 SUTTER: Because that's the only place 639 00:31:15,266 --> 00:31:18,166 with enough material to power them. 640 00:31:18,233 --> 00:31:19,687 But in 3C186, that's not what we see. 641 00:31:19,687 --> 00:31:21,567 But in 3C186, that's not what we see. 642 00:31:21,667 --> 00:31:24,000 The supermassive black hole is displaced from 643 00:31:24,066 --> 00:31:25,667 the center, and not a little bit. 644 00:31:25,734 --> 00:31:27,934 It's 35,000 light-years. 645 00:31:28,000 --> 00:31:30,867 So to see a quasar 35,000 light-years away from 646 00:31:30,967 --> 00:31:33,600 the core means something really violent 647 00:31:33,667 --> 00:31:34,867 had to happen there. 648 00:31:34,934 --> 00:31:37,867 ROWE: The quasar is racing away from the center 649 00:31:37,967 --> 00:31:41,867 of the galaxy at over four million miles an hour. 650 00:31:41,934 --> 00:31:44,266 OLUSEYI: That is insane. 651 00:31:44,367 --> 00:31:46,133 The magnitude of the energy 652 00:31:46,133 --> 00:31:49,687 and the forces required are just something unimaginable. 653 00:31:49,687 --> 00:31:50,333 and the forces required are just something unimaginable. 654 00:31:50,333 --> 00:31:55,567 So what can kick a giant black hole out of a galaxy? 655 00:31:55,567 --> 00:31:58,767 What has that kind of power? 656 00:31:58,867 --> 00:32:03,667 ROWE: The answer is a clash that wasn't evenly matched. 657 00:32:03,767 --> 00:32:08,000 The two supermassive black holes were different sizes -- 658 00:32:08,066 --> 00:32:11,734 a middleweight boxer taking on a heavyweight. 659 00:32:13,066 --> 00:32:15,767 When we humans set up a fight, we like to make it fair, 660 00:32:15,867 --> 00:32:17,066 because it's sport. 661 00:32:17,133 --> 00:32:18,500 Nature doesn't care about sport. 662 00:32:18,567 --> 00:32:19,687 It's survival of the fittest. 663 00:32:19,687 --> 00:32:20,000 It's survival of the fittest. 664 00:32:20,066 --> 00:32:21,500 This is not a fair fight. 665 00:32:21,567 --> 00:32:24,467 It's over before it even begins. 666 00:32:24,567 --> 00:32:26,767 One punch, and it's a K.O. 667 00:32:29,467 --> 00:32:31,667 As these two black holes are merging, 668 00:32:31,734 --> 00:32:33,767 there's one really small black hole 669 00:32:33,867 --> 00:32:35,233 and one much bigger black hole. 670 00:32:35,233 --> 00:32:38,133 The whole system wobbles around, and it can get more of 671 00:32:38,133 --> 00:32:40,000 a gravitational wave kick in one 672 00:32:40,066 --> 00:32:42,767 direction than the other. -And that's momentum. 673 00:32:42,867 --> 00:32:46,166 That's a push, that's enough energy to kick 674 00:32:46,233 --> 00:32:47,567 the black hole out. 675 00:32:49,500 --> 00:32:49,687 ROWE: The lopsided gravitational punch 676 00:32:49,687 --> 00:32:51,767 ROWE: The lopsided gravitational punch 677 00:32:51,867 --> 00:32:53,867 sends the merged supermassive 678 00:32:53,967 --> 00:32:56,734 black hole on a one-way trip to oblivion. 679 00:32:58,467 --> 00:33:00,100 This tells us that gravitational 680 00:33:00,100 --> 00:33:02,667 waves can be tremendously powerful. 681 00:33:02,767 --> 00:33:05,567 They can move a supermassive black hole out from 682 00:33:05,667 --> 00:33:08,867 the center of a galaxy and send it on its way. 683 00:33:08,967 --> 00:33:10,400 PONTZEN: But it just carries on drifting. 684 00:33:10,467 --> 00:33:12,500 There's no way to stop it. 685 00:33:12,567 --> 00:33:14,467 And who knows, in a few million years it could 686 00:33:14,567 --> 00:33:17,266 just drift entirely out of its galaxy 687 00:33:17,333 --> 00:33:19,687 and go floating off into deep space. 688 00:33:19,687 --> 00:33:19,867 and go floating off into deep space. 689 00:33:22,166 --> 00:33:24,133 ROWE: In some matches, the fighters 690 00:33:24,133 --> 00:33:25,767 don't even land a punch. 691 00:33:27,767 --> 00:33:30,834 Scientists spot a supermassive black hole 692 00:33:30,834 --> 00:33:35,567 named B3 1715 425. 693 00:33:36,867 --> 00:33:39,000 This black hole is strange. 694 00:33:40,567 --> 00:33:42,266 Stripped of all its stars, 695 00:33:42,367 --> 00:33:46,834 it hurtles through empty space at 4.5 million miles an hour. 696 00:33:46,834 --> 00:33:48,967 The first thing that draws our attention is 697 00:33:49,033 --> 00:33:49,687 this faint trail of debris across the sky. 698 00:33:49,687 --> 00:33:53,133 this faint trail of debris across the sky. 699 00:33:53,133 --> 00:33:55,266 PLAIT: There is actually a trail leading 700 00:33:55,367 --> 00:33:57,100 back to the center of the galaxy. 701 00:33:57,166 --> 00:33:59,667 It's kind of like a dump truck, right, that's filled with 702 00:33:59,767 --> 00:34:02,100 dirt driving down the highway, and the dirt's flying off 703 00:34:02,166 --> 00:34:05,233 behind it -- this is a naked black hole. 704 00:34:05,233 --> 00:34:07,500 ROWE: The exposed super massive black hole 705 00:34:07,567 --> 00:34:09,834 has lost its stars and galaxy, 706 00:34:09,834 --> 00:34:14,467 a champion stripped of its fans and entourage. 707 00:34:14,567 --> 00:34:17,767 So what event is powerful enough to strip 708 00:34:17,867 --> 00:34:19,687 a supermassive black hole of its entire host galaxy? 709 00:34:19,687 --> 00:34:22,467 a supermassive black hole of its entire host galaxy? 710 00:34:22,567 --> 00:34:24,400 That has to be something really big. 711 00:34:26,967 --> 00:34:29,033 PLAIT: B3 is a smallish galaxy, and it 712 00:34:29,100 --> 00:34:31,233 got into a scrap with a much bigger one. 713 00:34:31,233 --> 00:34:33,266 The stronger gravity of the bigger galaxy 714 00:34:33,333 --> 00:34:36,333 stripped the stars away from that black hole and shot it out. 715 00:34:38,567 --> 00:34:40,166 Typically in the universe, when something 716 00:34:40,233 --> 00:34:42,133 is bigger and more massive, it wins. 717 00:34:42,133 --> 00:34:43,867 So this is true for galaxies. 718 00:34:43,967 --> 00:34:46,667 A big galaxy versus a little galaxy -- 719 00:34:46,767 --> 00:34:48,033 put your money on the big one. 720 00:34:49,567 --> 00:34:49,687 ROWE: But when two evenly matched heavyweights 721 00:34:49,687 --> 00:34:52,266 ROWE: But when two evenly matched heavyweights 722 00:34:52,367 --> 00:34:53,266 enter the ring, 723 00:34:54,767 --> 00:34:57,367 it's time for the main event. 724 00:34:57,367 --> 00:34:58,934 [crowd chanting] 725 00:34:59,000 --> 00:35:01,500 A clash of the titans. 726 00:35:01,567 --> 00:35:04,100 I grew up watching boxing with my dad. 727 00:35:04,166 --> 00:35:08,000 So I've always been a boxing fan, and I love a great battle. 728 00:35:08,066 --> 00:35:10,166 And what's a bigger battle than 729 00:35:10,266 --> 00:35:14,266 a head-on collision between two supermassive black holes? 730 00:35:14,333 --> 00:35:17,667 If you're a boxing fan, this is the big one. 731 00:35:17,734 --> 00:35:18,867 SUTTER: We are ready. 732 00:35:18,967 --> 00:35:19,687 We are on the edge of our seats. 733 00:35:19,687 --> 00:35:21,467 We are on the edge of our seats. 734 00:35:21,567 --> 00:35:24,166 MINGARELLI: We've got two supermassive black holes, 735 00:35:24,233 --> 00:35:26,967 each one is in their corner, and they're getting ready for 736 00:35:27,033 --> 00:35:28,333 the fight of the century. 737 00:35:30,667 --> 00:35:33,467 I mean, they're just gonna go at it like goosh, goosh. 738 00:35:33,567 --> 00:35:36,367 I would watch that. I'd Pay-Per-View that. 739 00:35:36,467 --> 00:35:37,767 OLUSEYI: It doesn't get any better than this. 740 00:35:37,867 --> 00:35:40,967 These are prize fighters at the top of their game. 741 00:35:41,033 --> 00:35:42,567 They're trained to a T. 742 00:35:42,567 --> 00:35:43,934 They're beefed up. 743 00:35:44,000 --> 00:35:46,400 They are ready to rumble. 744 00:35:46,467 --> 00:35:49,687 ROWE: We are just seconds away from the fight of the cosmos. 745 00:35:49,687 --> 00:35:51,000 ROWE: We are just seconds away from the fight of the cosmos. 746 00:36:02,867 --> 00:36:05,133 ROWE: Welcome to the heavyweight championship 747 00:36:05,133 --> 00:36:06,500 of the universe. 748 00:36:06,567 --> 00:36:09,867 Weighing in at eight billion solar masses, 749 00:36:09,934 --> 00:36:15,333 We have the galactic destroyer, M101 star. 750 00:36:15,333 --> 00:36:16,967 And in the other corner, 751 00:36:17,033 --> 00:36:20,567 at a punishing 7.8 billion suns, 752 00:36:20,667 --> 00:36:23,985 the star crusher, NSC47 star. 753 00:36:23,985 --> 00:36:24,867 the star crusher, NSC47 star. 754 00:36:24,967 --> 00:36:28,100 They are pumped and ready to rumble. 755 00:36:28,166 --> 00:36:31,367 So here it is, we're finally here. 756 00:36:31,433 --> 00:36:34,033 The crowd is roaring. 757 00:36:34,100 --> 00:36:35,600 The bell has rung, 758 00:36:35,667 --> 00:36:37,867 and the fighters are approaching each other. 759 00:36:37,934 --> 00:36:39,967 They are ready to go at it. 760 00:36:42,033 --> 00:36:43,767 ROWE: Let's have a clean fight, fellas. 761 00:36:43,834 --> 00:36:46,367 Touch hands, and go back to your corners. 762 00:36:48,066 --> 00:36:51,100 Round one. The two heavyweights circle, 763 00:36:51,166 --> 00:36:53,467 testing the other's defenses. 764 00:36:53,467 --> 00:36:53,985 The black hole's gonna do what the boxes are gonna do. 765 00:36:53,985 --> 00:36:55,767 The black hole's gonna do what the boxes are gonna do. 766 00:36:55,834 --> 00:36:57,467 They're gonna circle each other, 767 00:36:57,567 --> 00:36:59,000 and they're gonna orbit each other, 768 00:36:59,066 --> 00:37:00,834 and they're gonna size each other up. 769 00:37:02,567 --> 00:37:04,767 PLAIT: Once these two supermassive black holes 770 00:37:04,834 --> 00:37:06,567 are close enough, their gravity, 771 00:37:06,667 --> 00:37:08,834 inexorably, is gonna draw them together. 772 00:37:11,467 --> 00:37:14,467 ROWE: As the two supermassive black holes get closer, 773 00:37:14,467 --> 00:37:17,166 they throw a few exploratory jabs, 774 00:37:20,834 --> 00:37:23,667 triggering bursts of gravitational waves 775 00:37:23,734 --> 00:37:23,985 that warp everything in their path. 776 00:37:23,985 --> 00:37:25,600 that warp everything in their path. 777 00:37:27,066 --> 00:37:30,266 These enormous gravitational waves are completely 778 00:37:30,367 --> 00:37:33,600 deforming the fabric of spacetime around them. 779 00:37:33,667 --> 00:37:35,834 Not just a little bit, but a lot. 780 00:37:35,834 --> 00:37:39,266 It's like feeling the fighters approach in 781 00:37:39,333 --> 00:37:41,567 the boxing ring... 782 00:37:41,567 --> 00:37:44,367 from the next town over. 783 00:37:48,567 --> 00:37:52,333 ROWE: Next, the supermassive black hole's gravity throws in 784 00:37:52,333 --> 00:37:53,967 a couple of right hooks 785 00:37:54,033 --> 00:37:56,333 straight into the accretion disks. 786 00:37:59,767 --> 00:38:02,367 MINGARELLI: What could happen is that they start to form 787 00:38:02,433 --> 00:38:03,600 like an angle grinder. 788 00:38:03,667 --> 00:38:07,066 You'll see sparks flying as they try to merge and form 789 00:38:07,133 --> 00:38:08,967 a new single accretion disk. 790 00:38:09,033 --> 00:38:11,367 When those accretion disks collide, 791 00:38:11,467 --> 00:38:16,100 the whole thing is gonna light up like the Fourth of July. 792 00:38:16,166 --> 00:38:19,767 ROWE: Spiraling in at millions of miles an hour, 793 00:38:19,867 --> 00:38:21,934 the heavyweight fighters get close, 794 00:38:22,000 --> 00:38:23,985 delivering punishing body blows. 795 00:38:23,985 --> 00:38:24,233 delivering punishing body blows. 796 00:38:28,667 --> 00:38:30,934 The event horizons, the surface of 797 00:38:31,000 --> 00:38:34,166 the supermassive black holes, are about to touch. 798 00:38:36,100 --> 00:38:37,433 In their final moments, 799 00:38:37,433 --> 00:38:40,333 these two supermassive black holes are orbiting each other 800 00:38:40,333 --> 00:38:42,266 at a significant fraction 801 00:38:42,333 --> 00:38:44,667 of the speed of light, and their event horizons 802 00:38:44,767 --> 00:38:45,767 will touch. 803 00:38:47,600 --> 00:38:49,967 And they'll eventually merge into one new 804 00:38:50,033 --> 00:38:51,767 supermassive black hole. 805 00:38:51,867 --> 00:38:53,100 TEGMARK: You might think, 806 00:38:53,166 --> 00:38:53,985 don't they bump into each other like bowling balls? 807 00:38:53,985 --> 00:38:55,467 don't they bump into each other like bowling balls? 808 00:38:55,567 --> 00:38:56,734 No, they don't. 809 00:38:56,767 --> 00:38:58,734 Because what we're calling the edge of a black hole is 810 00:38:58,734 --> 00:39:01,600 actually not a thing -- that's just 811 00:39:01,667 --> 00:39:03,500 the surface around the black hole. 812 00:39:03,567 --> 00:39:06,433 Gravity is so strong that nothing can come out. 813 00:39:06,433 --> 00:39:10,367 ROWE: The two supermassive black holes finally merge, 814 00:39:10,433 --> 00:39:14,367 releasing around 5 percent of the mass they've gathered over 815 00:39:14,433 --> 00:39:16,367 billions of years in 816 00:39:16,467 --> 00:39:20,734 an enormous burst of gravitational waves. 817 00:39:20,734 --> 00:39:22,734 The amount of energy that we're talking about... 818 00:39:24,867 --> 00:39:27,667 there's nothing to compare it to -- it's mind-crushing. 819 00:39:27,767 --> 00:39:30,967 There's really almost no point in thinking about it. 820 00:39:31,033 --> 00:39:33,367 It's just not something I think that I can 821 00:39:33,433 --> 00:39:34,600 wrap my head around. 822 00:39:34,667 --> 00:39:36,667 Coming from where I come from, 823 00:39:36,767 --> 00:39:38,500 you know, you don't show weakness, 824 00:39:38,567 --> 00:39:41,367 so I'm not gonna say that the collision of two black holes 825 00:39:41,467 --> 00:39:44,166 is more powerful than one of my punches, but... 826 00:39:45,500 --> 00:39:46,834 it's close. 827 00:39:48,233 --> 00:39:52,166 ROWE: The gigantic and powerful gravitational waves race out 828 00:39:52,233 --> 00:39:53,967 from the collision zone, 829 00:39:54,033 --> 00:39:57,767 leaving a single merged black hole. 830 00:39:57,867 --> 00:40:02,133 The supermassive black hole, after it merges, permanently 831 00:40:02,133 --> 00:40:05,767 deforms the fabric of spacetime around it, and this deformation 832 00:40:05,834 --> 00:40:07,867 travels out at the speed of light. 833 00:40:09,500 --> 00:40:13,367 ROWE: The surviving 95 percent of mass from the two colliding 834 00:40:13,467 --> 00:40:15,433 supermassive black holes 835 00:40:15,433 --> 00:40:20,266 is now locked in a single ultramassive black hole, 836 00:40:20,333 --> 00:40:23,934 the undisputed super heavyweight champion of 837 00:40:24,000 --> 00:40:26,567 the universe -- at least for now. 838 00:40:27,867 --> 00:40:30,166 It seems the universe is always upping the ante. 839 00:40:30,233 --> 00:40:32,066 Could there be something even more 840 00:40:32,133 --> 00:40:33,600 violent we haven't even discovered yet? 841 00:40:33,667 --> 00:40:36,333 The universe keeps wanting to give us 842 00:40:36,333 --> 00:40:38,567 something more violent all the time. 843 00:40:38,667 --> 00:40:43,266 ROWE: Energy locked in hydrogen atoms formed at the birth of 844 00:40:43,333 --> 00:40:45,667 the universe is finally 845 00:40:45,767 --> 00:40:49,767 released in the violent collision and builds 846 00:40:49,867 --> 00:40:51,867 an ultramassive black hole. 847 00:40:54,734 --> 00:40:57,567 SUTTER: This is one of the most beautiful stories in 848 00:40:57,667 --> 00:41:00,600 our universe -- you have the most energetic collision, 849 00:41:00,667 --> 00:41:02,367 the most amount of energy released, 850 00:41:02,467 --> 00:41:05,033 the most violent event, can trace 851 00:41:05,100 --> 00:41:08,266 its origins to the humble hydrogen atom. 852 00:41:11,133 --> 00:41:14,467 ROWE: So we have our champion -- matter compressed 853 00:41:14,567 --> 00:41:17,767 and then smashed together by supermassive black holes 854 00:41:17,834 --> 00:41:21,367 creates the most violent event in the universe. 855 00:41:22,600 --> 00:41:23,985 I don't think there's a contest. 856 00:41:23,985 --> 00:41:24,367 I don't think there's a contest. 857 00:41:24,433 --> 00:41:26,567 The supermassive black hole collisions 858 00:41:26,567 --> 00:41:28,233 are the most energetic, 859 00:41:28,233 --> 00:41:32,834 just, like, mind-numbingly large amounts of energy in 860 00:41:32,834 --> 00:41:33,967 these collisions. 861 00:41:36,867 --> 00:41:39,734 A merger of two supermassive black holes 862 00:41:39,734 --> 00:41:43,066 is at the absolute top end extreme of that 863 00:41:43,133 --> 00:41:46,867 for all possible events in the entire universe, 864 00:41:46,967 --> 00:41:49,867 A supermassive black hole merger is the most 865 00:41:49,934 --> 00:41:53,000 violent thing that we can observe in the universe.