1 00:00:00,900 --> 00:00:02,866 ♪ ♪ 2 00:00:02,900 --> 00:00:06,700 NARRATOR: Something is hiding in the darkness. 3 00:00:06,733 --> 00:00:10,033 {\an1}Invisible objects of unimaginable power 4 00:00:10,066 --> 00:00:16,233 {\an1}that could hold the key to solving the mysteries of space, 5 00:00:16,266 --> 00:00:20,600 {\an1}time, and the universe itself. 6 00:00:20,633 --> 00:00:23,000 {\an1}To me, a black hole is 7 00:00:23,033 --> 00:00:27,466 {\an1}the greatest exhibition of nature's mysterious powers. 8 00:00:27,500 --> 00:00:29,366 SUGATA KAVIRAJ: You literally can't see them. 9 00:00:29,400 --> 00:00:31,333 {\an1}And that's what makes them extremely mysterious. 10 00:00:31,366 --> 00:00:35,500 NARRATOR: They are bizarre quirks of nature. 11 00:00:35,533 --> 00:00:36,666 BECKY SMETHURST: When we're studying black holes, 12 00:00:36,700 --> 00:00:38,633 {\an1}we're right on the edge of human knowledge. 13 00:00:40,766 --> 00:00:43,766 NARRATOR: And yet, they are sculptors of the cosmos. 14 00:00:43,800 --> 00:00:48,066 IMOGEN WHITTAM: The jets from black holes are so powerful, they can affect 15 00:00:48,100 --> 00:00:50,433 {\an1}the whole shape and nature of a galaxy. 16 00:00:50,466 --> 00:00:54,833 NARRATOR: Even shaping our own galaxy, the Milky Way. 17 00:00:54,866 --> 00:00:56,200 DELILAH GATES: We had hints that black holes 18 00:00:56,233 --> 00:00:58,700 {\an1}were at the center of all of galaxies, like our own. 19 00:00:58,733 --> 00:01:02,166 NARRATOR: Can we lift the veil... 20 00:01:02,200 --> 00:01:03,266 HAKEEM OLUSEYI: Forget the one-way trip to Mars. 21 00:01:03,300 --> 00:01:04,866 {\an1}I'm going in the black hole. 22 00:01:07,333 --> 00:01:09,800 NARRATOR: ...and reveal their secrets? 23 00:01:09,833 --> 00:01:11,800 {\an1}Fermi revealed something completely astonishing 24 00:01:11,833 --> 00:01:13,366 and unexpected. 25 00:01:13,400 --> 00:01:16,500 {\an1}We've never seen anything like it. 26 00:01:16,533 --> 00:01:20,566 {\an1}Finding these little pieces of the puzzle that did not fit 27 00:01:20,600 --> 00:01:22,933 {\an1}is super-exciting. 28 00:01:22,966 --> 00:01:24,866 {\an1}SHEPERD DOELEMAN: But if you really want to understand 29 00:01:24,900 --> 00:01:26,700 {\an1}the deepest questions of the universe, 30 00:01:26,733 --> 00:01:28,533 {\an1}you have to understand black holes. 31 00:01:28,566 --> 00:01:32,966 ♪ ♪ 32 00:01:33,000 --> 00:01:35,233 NARRATOR: "Black Holes," 33 00:01:35,266 --> 00:01:37,966 {\an1}right now, on "NOVA." 34 00:01:38,000 --> 00:01:42,433 ♪ ♪ 35 00:02:00,166 --> 00:02:02,833 {\an1}♪ See me when I float like a dove ♪ 36 00:02:02,866 --> 00:02:06,600 {\an1}♪ The skies above are lined with trees ♪ 37 00:02:06,633 --> 00:02:10,200 {\an1}♪ I'm on my knees, begging please ♪ 38 00:02:10,233 --> 00:02:16,333 {\an1}♪ Come and take me away ♪ 39 00:02:23,966 --> 00:02:30,266 ♪ ♪ 40 00:02:32,266 --> 00:02:34,800 NARRATOR: As we gaze out at the Milky Way, 41 00:02:34,833 --> 00:02:37,666 {\an1}our eyes are drawn to the light. 42 00:02:39,533 --> 00:02:42,166 {\an1}Hundreds of billions of stars 43 00:02:42,200 --> 00:02:47,366 {\an1}serenely spinning through the cosmos. 44 00:02:47,400 --> 00:02:49,333 WHITTAM: When we look up at the night sky, 45 00:02:49,366 --> 00:02:52,733 {\an7}the stars and planets that we see are beautiful. 46 00:02:52,766 --> 00:02:55,466 {\an8}But actually, it's in the space between these, 47 00:02:55,500 --> 00:02:56,633 {\an7}in the dark patches, 48 00:02:56,666 --> 00:03:00,033 {\an1}that some of the most fascinating things lie. 49 00:03:00,066 --> 00:03:03,400 ♪ ♪ 50 00:03:03,433 --> 00:03:06,200 NARRATOR: In places where there is no light, 51 00:03:06,233 --> 00:03:12,300 {\an1}objects of profound mystery bide their time. 52 00:03:12,333 --> 00:03:16,533 {\an1}Awesome in their simplicity and perfection, 53 00:03:16,566 --> 00:03:19,800 {\an1}we call them black holes. 54 00:03:19,833 --> 00:03:21,266 KIRSTEN HALL: A black hole 55 00:03:21,300 --> 00:03:26,466 {\an7}is an infinitely dense point in space from which nothing 56 00:03:26,500 --> 00:03:28,633 {\an7}can escape, not even light. 57 00:03:28,666 --> 00:03:31,766 {\an7}It's extraordinary to think that black holes are everywhere 58 00:03:31,800 --> 00:03:33,133 {\an8}in the universe, 59 00:03:33,166 --> 00:03:39,100 {\an1}that they have existed from very early times in the universe. 60 00:03:39,133 --> 00:03:43,166 NARRATOR: When quiet, they are almost impossible to detect. 61 00:03:43,200 --> 00:03:44,966 {\an1}URMILA CHADAYAMMURI: We're talking about a region of space 62 00:03:45,000 --> 00:03:46,366 {\an7}where, if something falls in, 63 00:03:46,400 --> 00:03:47,900 {\an7}we'll never know about it ever again. 64 00:03:47,933 --> 00:03:50,033 ♪ ♪ 65 00:03:50,066 --> 00:03:54,200 NARRATOR: They hold the power to shred stars and worlds, 66 00:03:54,233 --> 00:04:00,733 {\an1}but also, the potential to shape galaxies... 67 00:04:00,766 --> 00:04:03,500 {\an7}Black holes are one of the most fundamentally important 68 00:04:03,533 --> 00:04:07,933 {\an7}singular objects that might dictate how galaxies 69 00:04:07,966 --> 00:04:09,866 form and evolve. 70 00:04:09,900 --> 00:04:11,500 ANDREW PONTZEN: It's natural to fear them, 71 00:04:11,533 --> 00:04:13,200 {\an1}but we're learning that they're essential. 72 00:04:13,233 --> 00:04:14,600 {\an7}You can't live with them, 73 00:04:14,633 --> 00:04:16,566 {\an7}but you also can't live without them. 74 00:04:16,600 --> 00:04:19,900 ♪ ♪ 75 00:04:19,933 --> 00:04:22,766 NARRATOR: And they may hold the secret to the ultimate fate 76 00:04:22,800 --> 00:04:25,333 of the universe. 77 00:04:25,366 --> 00:04:27,000 HALL: Black holes, on a fundamental level, 78 00:04:27,033 --> 00:04:30,466 {\an1}challenge our understanding of physics, 79 00:04:30,500 --> 00:04:34,900 {\an1}of the way that everything in the universe works. 80 00:04:34,933 --> 00:04:37,233 {\an7}Black holes are the most mysterious objects 81 00:04:37,266 --> 00:04:38,833 {\an8}in the universe, full stop. 82 00:04:38,866 --> 00:04:43,700 ♪ ♪ 83 00:04:43,733 --> 00:04:50,000 NARRATOR: To understand black holes, we have to start at the beginning. 84 00:04:50,033 --> 00:04:54,333 {\an1}At the moment of birth. 85 00:04:54,366 --> 00:04:58,700 {\an1}CHIARA MINGARELLI: Black holes that are a few times the mass of the sun 86 00:04:58,733 --> 00:05:02,500 {\an7}probably formed from giant stars that were maybe about 87 00:05:02,533 --> 00:05:05,566 {\an8}20 to 30 times the mass of the sun. 88 00:05:05,600 --> 00:05:08,700 ♪ ♪ 89 00:05:08,733 --> 00:05:15,633 NARRATOR: Enormous stars burning bright blue with intense heat. 90 00:05:15,666 --> 00:05:20,033 {\an1}But the brightest stars are the shortest-lived. 91 00:05:20,066 --> 00:05:23,133 TREMBLAY: A star is a big ball of gas, right? 92 00:05:23,166 --> 00:05:24,800 {\an1}There's outward gravity pushing in, right? 93 00:05:24,833 --> 00:05:26,500 {\an1}The thing wants to collapse in on itself 94 00:05:26,533 --> 00:05:28,000 {\an1}under its own self-gravity. 95 00:05:28,033 --> 00:05:30,100 {\an1}But the fusion that's happening within the star's core 96 00:05:30,133 --> 00:05:34,233 {\an1}liberates so much light that the outward radiation pressure 97 00:05:34,266 --> 00:05:36,366 {\an1}prevents the collapse of that star. 98 00:05:38,533 --> 00:05:41,500 {\an7}But eventually, that gives up. 99 00:05:41,533 --> 00:05:47,400 {\an8}NARRATOR: A star like that can burn through its nuclear fuel 100 00:05:47,433 --> 00:05:50,533 {\an7}in just a few million years. 101 00:05:52,666 --> 00:05:59,600 {\an8}♪ ♪ 102 00:06:01,000 --> 00:06:03,700 {\an7}And when its power source runs out, 103 00:06:03,733 --> 00:06:09,533 {\an7}it collapses under its own gravitational pull. 104 00:06:09,566 --> 00:06:12,366 {\an1}There's so much material that's collapsing during 105 00:06:12,400 --> 00:06:17,333 {\an1}their final few moments that they create this massive 106 00:06:17,366 --> 00:06:19,466 {\an1}dense ball of neutrons 107 00:06:19,500 --> 00:06:24,366 {\an1}that continues to collapse. 108 00:06:24,400 --> 00:06:29,433 NARRATOR: A star 20 times the mass of our sun or larger... 109 00:06:30,933 --> 00:06:35,933 {\an1}...crushed by the force of gravity, 110 00:06:35,966 --> 00:06:41,633 {\an1}until the star disappears, 111 00:06:41,666 --> 00:06:44,933 {\an1}leaving only a ghost behind. 112 00:06:44,966 --> 00:06:47,966 ♪ ♪ 113 00:06:48,000 --> 00:06:50,733 A black hole. 114 00:06:50,766 --> 00:06:53,400 ♪ ♪ 115 00:06:53,433 --> 00:06:57,566 {\an1}This transformation does not await all stars. 116 00:06:57,600 --> 00:07:02,133 {\an1}Smaller, less massive stars, like our sun, 117 00:07:02,166 --> 00:07:06,000 {\an1}eventually become burnt-out dwarves when their fusion stops: 118 00:07:06,033 --> 00:07:11,300 {\an1}slowly fading cinders. 119 00:07:11,333 --> 00:07:14,033 {\an1}But it's possible that almost all the massive stars 120 00:07:14,066 --> 00:07:18,300 {\an1}that dominated the early universe formed black holes 121 00:07:18,333 --> 00:07:22,266 when they died. 122 00:07:22,300 --> 00:07:25,933 {\an1}Because black holes are simply what happens when enough matter 123 00:07:25,966 --> 00:07:29,800 {\an1}is crushed into a small enough volume, 124 00:07:29,833 --> 00:07:33,433 {\an1}dramatically warping the space around it. 125 00:07:33,466 --> 00:07:36,366 DAVID ROSARIO: A river is a great analogy for the area right around 126 00:07:36,400 --> 00:07:37,933 a black hole. 127 00:07:37,966 --> 00:07:42,766 {\an7}Here I am far upstream, and the water is fairly placid. 128 00:07:42,800 --> 00:07:44,433 {\an7}It's not moving too fast. 129 00:07:44,466 --> 00:07:46,966 {\an1}If I were to get into the water here and swim across, 130 00:07:47,000 --> 00:07:50,266 {\an1}I'd be able to do that very easily. 131 00:07:50,300 --> 00:07:52,533 {\an1}In the same way, if you're far away from a black hole, 132 00:07:52,566 --> 00:07:55,466 {\an1}you'll be able to get around with just a normal spacecraft 133 00:07:55,500 --> 00:07:59,200 {\an1}without too much trouble and simple propulsion. 134 00:07:59,233 --> 00:08:03,766 ♪ ♪ 135 00:08:03,800 --> 00:08:06,533 NARRATOR: But the closer you get to the black hole, 136 00:08:06,566 --> 00:08:10,500 {\an1}the stranger things become. 137 00:08:10,533 --> 00:08:13,366 {\an1}The collapsed massive star crushes down 138 00:08:13,400 --> 00:08:15,633 {\an1}so small and so dense, 139 00:08:15,666 --> 00:08:19,200 {\an1}it ceases to have a physical surface at all, 140 00:08:19,233 --> 00:08:23,933 {\an1}becoming an infinitely small point in space, 141 00:08:23,966 --> 00:08:30,500 {\an1}exerting a profound effect on the space-time around it. 142 00:08:30,533 --> 00:08:34,433 ROSARIO: As the water gets closer to the waterfall, 143 00:08:34,466 --> 00:08:37,300 {\an1}the speed of the water increases. 144 00:08:37,333 --> 00:08:41,300 {\an1}If I were to jump into the water right here, 145 00:08:41,333 --> 00:08:43,500 {\an1}the speed of the current would be so intense 146 00:08:43,533 --> 00:08:46,166 {\an1}that I wouldn't be able to swim against it, 147 00:08:46,200 --> 00:08:49,066 {\an1}and I would be gradually pulled closer to the edge 148 00:08:49,100 --> 00:08:51,700 {\an1}of the waterfall till I reach a point of no return. 149 00:08:51,733 --> 00:08:54,433 {\an1}And that's the same around a black hole. 150 00:08:54,466 --> 00:08:56,900 ♪ ♪ 151 00:08:56,933 --> 00:09:01,733 NARRATOR: Just outside the black hole, the fabric of space itself 152 00:09:01,766 --> 00:09:05,966 {\an1}actually stretches inward towards the center. 153 00:09:07,833 --> 00:09:12,700 ROSARIO: Not even stars, planets, people, even light cannot escape 154 00:09:12,733 --> 00:09:14,366 {\an1}the pull of a black hole. 155 00:09:14,400 --> 00:09:17,766 {\an1}It's like a waterfall in the fabric of the universe. 156 00:09:20,566 --> 00:09:26,033 NARRATOR: The black hole's gravitational reach is not infinite. 157 00:09:26,066 --> 00:09:28,766 CHADAYAMMURI: People have this idea that black holes suck, 158 00:09:28,800 --> 00:09:31,033 {\an1}in the sense that they suck everything into them, 159 00:09:31,066 --> 00:09:32,333 {\an1}but that's not true. 160 00:09:32,366 --> 00:09:35,533 {\an1}Black holes can only eat things that are within 161 00:09:35,566 --> 00:09:38,766 {\an1}a certain distance away from them. 162 00:09:38,800 --> 00:09:40,200 {\an1}If you're further away, 163 00:09:40,233 --> 00:09:46,266 {\an1}then the black hole has no way of eating you. 164 00:09:46,300 --> 00:09:50,666 NARRATOR: But once in its grasp, you are lost forever. 165 00:09:50,700 --> 00:09:54,700 {\an1}And this is the key to their mystery. 166 00:09:54,733 --> 00:09:58,566 {\an1}The black hole's interior is hidden from view, 167 00:09:58,600 --> 00:10:03,666 {\an1}cut off from the rest of the universe by a boundary in space: 168 00:10:03,700 --> 00:10:07,166 {\an1}the event horizon. 169 00:10:07,200 --> 00:10:10,866 {\an1}Beyond this point, there is no escape. 170 00:10:12,733 --> 00:10:16,400 ♪ ♪ 171 00:10:16,433 --> 00:10:18,933 As we approach the event horizon, 172 00:10:18,966 --> 00:10:25,100 {\an1}we get our first glimpse of the true weirdness of black holes. 173 00:10:28,166 --> 00:10:29,966 ROSARIO: Ever since Einstein, 174 00:10:30,000 --> 00:10:31,800 {\an1}we've viewed the fabric of the universe 175 00:10:31,833 --> 00:10:36,300 {\an1}not as something static, but instead something that's fluid, 176 00:10:36,333 --> 00:10:40,966 {\an1}something that bends and warps around objects with mass. 177 00:10:41,000 --> 00:10:45,333 {\an1}We call this space-time, a combination of space and time. 178 00:10:45,366 --> 00:10:49,800 {\an1}See, Einstein's insight was to realize that these two things 179 00:10:49,833 --> 00:10:51,833 {\an1}are intimately connected. 180 00:10:51,866 --> 00:10:56,466 {\an1}That when an object has mass, it not just bends space, 181 00:10:56,500 --> 00:10:59,633 {\an1}but changes the passage of time itself. 182 00:10:59,666 --> 00:11:05,133 {\an1}In particular, the effect of a mass is to slow time down. 183 00:11:06,733 --> 00:11:09,133 NARRATOR: In the region around the black hole, 184 00:11:09,166 --> 00:11:10,233 {\an1}the warped space-time 185 00:11:10,266 --> 00:11:15,866 {\an1}elongates light waves, distorting color. 186 00:11:15,900 --> 00:11:19,433 {\an7}The event horizon is the place at which time stops 187 00:11:19,466 --> 00:11:21,133 {\an1}when seen from far away. 188 00:11:21,166 --> 00:11:23,733 {\an1}Someone who's outside the black hole will see you get 189 00:11:23,766 --> 00:11:25,433 {\an1}redder and redder... 190 00:11:25,466 --> 00:11:27,900 {\an1}(speech slowing): And your time will slow down. 191 00:11:27,933 --> 00:11:29,766 (normally): And you'll kind of pass through 192 00:11:29,800 --> 00:11:31,200 {\an1}the horizon, disappear forever. 193 00:11:31,233 --> 00:11:34,366 ♪ ♪ 194 00:11:49,766 --> 00:11:54,900 ♪ ♪ 195 00:12:08,300 --> 00:12:15,366 NARRATOR: Black holes are like waterfalls in the fabric of the universe, 196 00:12:15,400 --> 00:12:20,833 {\an1}where space contorts and time itself grinds to a halt, 197 00:12:20,866 --> 00:12:23,666 ensnaring light, 198 00:12:23,700 --> 00:12:29,966 {\an1}making them lockboxes for the universe's ultimate secrets. 199 00:12:32,300 --> 00:12:37,800 ♪ ♪ 200 00:12:43,300 --> 00:12:47,500 STEPHEN HAWKING: It is said that fact is sometimes stranger than fiction, 201 00:12:47,533 --> 00:12:52,133 {\an1}and nowhere is that more true than in the case of black holes. 202 00:12:54,000 --> 00:12:57,466 {\an1}Black holes are stranger than anything dreamed up 203 00:12:57,500 --> 00:12:59,400 {\an1}by science fiction writers, 204 00:12:59,433 --> 00:13:03,133 {\an1}but they are firmly matters of science fact. 205 00:13:09,666 --> 00:13:13,200 NARRATOR: The vast majority of black holes are small-- 206 00:13:13,233 --> 00:13:16,533 {\an1}less than 20 miles across-- 207 00:13:16,566 --> 00:13:21,633 {\an1}and they usually wander alone through space. 208 00:13:21,666 --> 00:13:25,033 {\an1}But if we turn our gaze towards the center of the Milky Way 209 00:13:25,066 --> 00:13:26,966 {\an1}and journey inwards, 210 00:13:27,000 --> 00:13:32,866 {\an1}through the gas and dust that shroud the galactic core, 211 00:13:32,900 --> 00:13:36,633 {\an1}signs of something altogether different appear. 212 00:13:36,666 --> 00:13:38,200 TREMBLAY: If you simply observe 213 00:13:38,233 --> 00:13:42,200 {\an7}the stars in the very heart of our galaxy over about 20 years, 214 00:13:42,233 --> 00:13:45,266 {\an7}you will observe them orbiting nothing. 215 00:13:47,766 --> 00:13:51,900 {\an1}At the center of this swarm of stars is darkness. 216 00:13:51,933 --> 00:13:53,700 It's a void. 217 00:13:53,733 --> 00:13:59,233 NARRATOR: Scientists name this invisible enigma Sagittarius A-star, 218 00:13:59,266 --> 00:14:02,633 {\an1}although it is not a star at all. 219 00:14:02,666 --> 00:14:03,933 PONTZEN: Can you imagine 220 00:14:03,966 --> 00:14:07,666 {\an7}how massive that object has to be to be able to pull 221 00:14:07,700 --> 00:14:10,033 {\an7}entire stars into orbit? 222 00:14:11,666 --> 00:14:13,800 NARRATOR: They believe it to be a black hole 223 00:14:13,833 --> 00:14:18,033 {\an1}more than four million times the mass of our sun-- 224 00:14:18,066 --> 00:14:19,666 {\an1}many thousands of times more massive 225 00:14:19,700 --> 00:14:22,833 than any other in the Milky Way. 226 00:14:22,866 --> 00:14:24,066 KAVIRAJ: How did this monster 227 00:14:24,100 --> 00:14:26,433 {\an7}come to live at the heart of the Milky Way? 228 00:14:26,466 --> 00:14:32,166 NARRATOR: Sagittarius A-star is a supermassive giant 229 00:14:32,200 --> 00:14:36,466 {\an1}around which the entire galaxy spins, 230 00:14:36,500 --> 00:14:40,766 {\an1}raising intriguing new questions about the role of black holes 231 00:14:40,800 --> 00:14:44,400 {\an1}in our galaxy and the universe. 232 00:14:44,433 --> 00:14:46,366 {\an7}How did it get there? 233 00:14:46,400 --> 00:14:49,266 {\an7}How did it get so big? 234 00:14:49,300 --> 00:14:52,266 {\an7}And what can it tell us about how black holes 235 00:14:52,300 --> 00:14:54,600 {\an7}shape the cosmos? 236 00:14:54,633 --> 00:14:56,333 SMETHURST: Would we even be here today 237 00:14:56,366 --> 00:14:58,300 {\an1}without Sagittarius A-star? 238 00:15:03,533 --> 00:15:05,666 WOMAN: Just a few minutes away from the 26th flight 239 00:15:05,700 --> 00:15:06,966 {\an1}of the shuttle Columbia, 240 00:15:07,000 --> 00:15:08,700 {\an1}with a crew of five. 241 00:15:08,733 --> 00:15:13,266 ♪ ♪ 242 00:15:15,366 --> 00:15:18,700 KIMBERLY ARCAND: I think a night launch is particularly exciting. 243 00:15:18,733 --> 00:15:21,600 WOMAN: Go for engine start. 244 00:15:21,633 --> 00:15:25,200 {\an1}We have booster ignition and lift-off of Columbia. 245 00:15:25,233 --> 00:15:27,933 MAN: Roger roll, Columbia, we're looking in. 246 00:15:29,300 --> 00:15:31,766 CHADAYAMMURI: Chandra is huge. 247 00:15:31,800 --> 00:15:33,200 {\an7}It's about the size of a school bus. 248 00:15:33,233 --> 00:15:34,566 {\an7}It's the largest telescope 249 00:15:34,600 --> 00:15:37,400 {\an1}to ever be launched by the space shuttle. 250 00:15:37,433 --> 00:15:41,100 ♪ ♪ 251 00:15:41,133 --> 00:15:44,966 MAN: SRB separation is confirmed. 252 00:15:45,000 --> 00:15:46,733 {\an7}You're stressed about the astronauts onboard 253 00:15:46,766 --> 00:15:49,333 {\an7}that are literally risking their lives to help us 254 00:15:49,366 --> 00:15:52,100 {\an7}get a better view of the universe. 255 00:15:56,233 --> 00:15:59,433 NARRATOR: In the summer of 1999, 256 00:15:59,466 --> 00:16:03,033 {\an1}NASA's flagship telescope for X-ray astronomy 257 00:16:03,066 --> 00:16:07,266 {\an1}sets off from the space shuttle cargo bay. 258 00:16:07,300 --> 00:16:11,800 ♪ ♪ 259 00:16:11,833 --> 00:16:14,533 TREMBLAY: Even two decades into its voyage of discovery, 260 00:16:14,566 --> 00:16:18,400 {\an1}Chandra remains by far the most powerful observatory 261 00:16:18,433 --> 00:16:21,266 {\an1}that we have to observe the high-energy universe. 262 00:16:25,633 --> 00:16:30,433 NARRATOR: Almost 83,000 miles above the Earth's surface, 263 00:16:30,466 --> 00:16:35,933 {\an1}at its highest orbit, Chandra scans the sky 264 00:16:35,966 --> 00:16:39,133 {\an1}with eight high-precision mirrors engineered 265 00:16:39,166 --> 00:16:43,966 {\an1}to detect X-rays emitted from extremely hot regions 266 00:16:44,000 --> 00:16:45,600 of the universe. 267 00:16:47,333 --> 00:16:52,900 {\an1}For 14 years, it searches among the exploding stars 268 00:16:52,933 --> 00:16:56,233 {\an1}and clusters of galaxies. 269 00:16:58,533 --> 00:17:02,933 But then, on September 14, 2013, 270 00:17:02,966 --> 00:17:08,400 {\an1}Chandra chances on something else entirely. 271 00:17:08,433 --> 00:17:10,500 WHITTAM: Chandra wasn't looking for this at all-- 272 00:17:10,533 --> 00:17:12,533 {\an1}just happened to be looking nearby. 273 00:17:12,566 --> 00:17:14,233 {\an1}So it was a total surprise. 274 00:17:14,266 --> 00:17:19,233 ♪ ♪ 275 00:17:19,266 --> 00:17:24,200 NARRATOR: As the telescope gazes into the constellation of Sagittarius, 276 00:17:24,233 --> 00:17:28,333 {\an1}it aims to observe a large cloud of hot gas. 277 00:17:28,366 --> 00:17:32,466 {\an7}But unexpectedly, 278 00:17:32,500 --> 00:17:37,466 {\an7}it records a flash of X-rays just a few pixels across 279 00:17:37,500 --> 00:17:44,033 {\an1}coming from the seemingly empty space in the galactic core. 280 00:17:44,066 --> 00:17:49,200 ♪ ♪ 281 00:17:52,400 --> 00:17:54,666 KAVIRAJ: When we see something get very hot for a very short period 282 00:17:54,700 --> 00:17:57,133 {\an1}of time, we get very excited. 283 00:17:57,166 --> 00:18:00,133 {\an1}Something is causing it-- something we can't see. 284 00:18:00,166 --> 00:18:05,266 {\an8}♪ ♪ 285 00:18:08,300 --> 00:18:12,566 NARRATOR: Some scientists believe the flash seen by Chandra 286 00:18:12,600 --> 00:18:15,733 {\an1}is caused by an asteroid... 287 00:18:17,166 --> 00:18:21,466 ♪ ♪ 288 00:18:21,500 --> 00:18:25,100 {\an1}...ripped apart and burning up in a blaze 289 00:18:25,133 --> 00:18:29,700 {\an7}hundreds of times brighter than the sun, 290 00:18:29,733 --> 00:18:34,266 {\an7}releasing a burst of X-rays that Chandra can detect 291 00:18:34,300 --> 00:18:38,800 {\an7}almost 26,000 light-years away. 292 00:18:38,833 --> 00:18:41,600 {\an7}If we see a level of X-rays being produced that's so bright, 293 00:18:41,633 --> 00:18:42,900 {\an7}it can't be explained 294 00:18:42,933 --> 00:18:45,700 {\an1}by any other process, then we know that there must be 295 00:18:45,733 --> 00:18:47,500 {\an1}a black hole there. 296 00:18:47,533 --> 00:18:51,566 NARRATOR: It's the behemoth at the center of our galaxy. 297 00:18:54,733 --> 00:18:57,866 {\an1}Sagittarius A-star. 298 00:19:00,966 --> 00:19:06,066 ♪ ♪ 299 00:19:06,100 --> 00:19:09,600 ARCAND: You can take a telescope like Chandra and watch a black hole 300 00:19:09,633 --> 00:19:11,166 {\an1}have a small snack, 301 00:19:11,200 --> 00:19:13,833 {\an1}maybe like a human might have a little biscuit in the afternoon. 302 00:19:13,866 --> 00:19:16,166 {\an1}And it's something like an asteroid. 303 00:19:16,200 --> 00:19:18,400 {\an1}And there will be a small sort of X-ray signature 304 00:19:18,433 --> 00:19:19,366 from that event. 305 00:19:19,400 --> 00:19:20,633 KAVIRAJ: So it's incredible 306 00:19:20,666 --> 00:19:23,500 {\an1}that we can actually observe Sagittarius A-star, 307 00:19:23,533 --> 00:19:26,266 {\an1}which lies 26,000 light-years away, 308 00:19:26,300 --> 00:19:30,533 {\an1}actually eating something. 309 00:19:30,566 --> 00:19:32,766 NARRATOR: But Chandra does not only look inwards. 310 00:19:32,800 --> 00:19:38,433 {\an1}It also looks out, beyond the Milky Way. 311 00:19:38,466 --> 00:19:43,366 {\an1}At the center of almost every large galaxy Chandra peers into, 312 00:19:43,400 --> 00:19:48,366 {\an1}it finds evidence that our galaxy is hardly unusual. 313 00:19:48,400 --> 00:19:50,733 SMETHURST: We started to spot 314 00:19:50,766 --> 00:19:53,666 {\an7}X-ray sources of light everywhere around the sky, 315 00:19:53,700 --> 00:19:56,533 {\an7}and we started to realize something weird was going on 316 00:19:56,566 --> 00:19:58,366 {\an7}in the centers of galaxies. 317 00:20:01,000 --> 00:20:03,400 DOELEMAN: At the heart of most galaxies, 318 00:20:03,433 --> 00:20:05,833 {\an1}we think now there are supermassive black holes, 319 00:20:05,866 --> 00:20:08,200 {\an7}black holes that weigh millions or billions of times 320 00:20:08,233 --> 00:20:09,833 {\an7}what our sun does. 321 00:20:09,866 --> 00:20:14,233 CROSTON: It's incredible that our modern X-ray telescopes, like Chandra, 322 00:20:14,266 --> 00:20:16,300 {\an1}allow us to map out 323 00:20:16,333 --> 00:20:20,533 {\an1}where these fascinating black holes are across the universe. 324 00:20:20,566 --> 00:20:22,200 ♪ ♪ 325 00:20:22,233 --> 00:20:26,266 NARRATOR: Supermassive black holes seem to be an integral feature 326 00:20:26,300 --> 00:20:28,600 of the cosmos. 327 00:20:28,633 --> 00:20:33,600 {\an1}But these supermassive objects raise questions. 328 00:20:33,633 --> 00:20:35,966 {\an1}How do they form? 329 00:20:36,000 --> 00:20:39,666 {\an1}And why are they so big? 330 00:20:39,700 --> 00:20:43,233 SMETHURST: These things form over millions to billions of years. 331 00:20:43,266 --> 00:20:45,366 {\an1}So we can't watch this happening. 332 00:20:45,400 --> 00:20:48,033 {\an1}We can only see it at various different stages 333 00:20:48,066 --> 00:20:49,633 {\an1}throughout the universe. 334 00:20:49,666 --> 00:20:53,933 {\an1}And so we have to just piece it together like a jigsaw puzzle. 335 00:20:53,966 --> 00:20:57,900 NARRATOR: Some scientists theorize that the biggest and oldest 336 00:20:57,933 --> 00:21:02,833 {\an1}black holes did not start life as stars at all. 337 00:21:02,866 --> 00:21:05,500 {\an1}PRIYAMVADA NATARAJAN: In the very early universe, we believe that 338 00:21:05,533 --> 00:21:08,500 {\an7}you could have formed very massive black hole seeds 339 00:21:08,533 --> 00:21:11,366 {\an7}by direct collapse of gas. 340 00:21:11,400 --> 00:21:15,300 {\an1}So these black holes are called direct-collapse black holes. 341 00:21:15,333 --> 00:21:19,200 NARRATOR: But the jury is still out. 342 00:21:19,233 --> 00:21:22,033 HALL: It's possible that Sagittarius A-star formed 343 00:21:22,066 --> 00:21:24,600 {\an1}by direct collapse of material. 344 00:21:24,633 --> 00:21:28,400 {\an7}What I think is more likely is that it formed by 345 00:21:28,433 --> 00:21:30,033 {\an7}the death of a star. 346 00:21:30,066 --> 00:21:36,066 NARRATOR: However Sagittarius A-star was born, one thing is certain: 347 00:21:36,100 --> 00:21:37,700 it had to grow. 348 00:21:37,733 --> 00:21:44,200 ♪ ♪ 349 00:21:44,233 --> 00:21:49,400 {\an1}The newly formed Sagittarius A-star begins to feast, 350 00:21:49,433 --> 00:21:54,533 {\an1}gorging itself on not just asteroids, 351 00:21:54,566 --> 00:22:01,466 {\an1}but bigger game, like stars and massive clouds of gas. 352 00:22:01,500 --> 00:22:02,900 WHITTAM: As it snacks on these 353 00:22:02,933 --> 00:22:06,800 {\an7}nearby objects that wander into its path, it gets bigger 354 00:22:06,833 --> 00:22:09,533 {\an1}and bigger and bigger. 355 00:22:11,466 --> 00:22:15,200 NARRATOR: The black hole gains more mass 356 00:22:15,233 --> 00:22:19,533 {\an1}and more gravitational power. 357 00:22:19,566 --> 00:22:22,433 MINGARELLI: But black holes that are a few times the mass of the sun 358 00:22:22,466 --> 00:22:25,000 {\an7}can never grow to be a supermassive black hole 359 00:22:25,033 --> 00:22:28,066 {\an7}just by eating gas and stars. 360 00:22:30,766 --> 00:22:36,666 NARRATOR: How did Sagittarius A-star speed up its growth? 361 00:22:36,700 --> 00:22:41,133 {\an1}On September 14, 2015, an international team 362 00:22:41,166 --> 00:22:45,166 {\an1}of astronomers finds a clue, 363 00:22:45,200 --> 00:22:50,066 {\an1}the aftershock of a truly titanic interaction: 364 00:22:50,100 --> 00:22:54,033 {\an1}two colliding black holes. 365 00:22:54,066 --> 00:22:56,933 TREMBLAY: So the merger of two black holes, as you might imagine, 366 00:22:56,966 --> 00:23:00,633 {\an1}is spectacularly energetic. 367 00:23:00,666 --> 00:23:03,766 {\an7}It is so energetic that it causes ripples in the fabric 368 00:23:03,800 --> 00:23:05,233 {\an7}of space-time itself that propagate outward 369 00:23:05,266 --> 00:23:06,466 {\an7}at the speed of light. 370 00:23:06,500 --> 00:23:10,266 {\an1}And we have detected these ripples here on Earth 371 00:23:10,300 --> 00:23:13,900 {\an1}with something we call LIGO. 372 00:23:13,933 --> 00:23:18,200 HALL: LIGO is an instrument that works by sending laser beams 373 00:23:18,233 --> 00:23:21,300 {\an1}that bounce off of mirrors. 374 00:23:21,333 --> 00:23:26,433 {\an1}When a gravitational wave passes by the Earth, 375 00:23:26,466 --> 00:23:30,033 {\an1}this changes the timing of the interaction 376 00:23:30,066 --> 00:23:32,133 {\an1}of those laser beams. 377 00:23:32,166 --> 00:23:35,200 DELILAH GATES: The stretching caused by a merger here on Earth 378 00:23:35,233 --> 00:23:36,866 {\an1}is absolutely minuscule. 379 00:23:36,900 --> 00:23:38,733 {\an7}But with advanced technology, 380 00:23:38,766 --> 00:23:40,400 {\an1}LIGO was able to do it. 381 00:23:40,433 --> 00:23:45,566 ♪ ♪ 382 00:23:50,000 --> 00:23:55,333 NARRATOR: Many scientists now think that mergers like this are the key 383 00:23:55,366 --> 00:23:57,900 {\an1}to how supermassive black holes, 384 00:23:57,933 --> 00:24:03,266 {\an1}like our own, grow so big. 385 00:24:03,300 --> 00:24:08,433 ♪ ♪ 386 00:24:14,100 --> 00:24:19,000 {\an1}When another black hole wanders towards Sagittarius A-star, 387 00:24:19,033 --> 00:24:25,266 {\an1}they become locked in a gravitational embrace. 388 00:24:25,300 --> 00:24:28,500 NATARAJAN: First, it is sort of an intriguing dance. 389 00:24:28,533 --> 00:24:30,766 {\an1}They kind of dance around each other, 390 00:24:30,800 --> 00:24:35,833 {\an1}lose energy, and slowly spiral into each other. 391 00:24:35,866 --> 00:24:39,533 ♪ ♪ 392 00:24:39,566 --> 00:24:41,966 {\an1}This dance gets faster and faster and faster and faster 393 00:24:42,000 --> 00:24:44,300 {\an1}until they finally merge. 394 00:24:44,333 --> 00:24:49,633 ♪ ♪ 395 00:24:49,666 --> 00:24:53,900 NARRATOR: Sagittarius A-star cannibalizes its cousin... 396 00:24:58,166 --> 00:25:03,500 {\an1}...creating ripples in the fabric of the universe itself. 397 00:25:03,533 --> 00:25:07,000 WHITTAM: These mergers were fundamental to making Sagittarius A-star 398 00:25:07,033 --> 00:25:09,100 {\an1}the monster that we see today. 399 00:25:09,133 --> 00:25:11,866 {\an1}They happened billions of years ago, right at the beginning 400 00:25:11,900 --> 00:25:13,433 {\an1}of Sagittarius A-star's life. 401 00:25:13,466 --> 00:25:17,066 ♪ ♪ 402 00:25:17,100 --> 00:25:19,133 NARRATOR: More meals follow. 403 00:25:21,500 --> 00:25:25,000 {\an1}Stars, gas clouds-- 404 00:25:25,033 --> 00:25:28,133 {\an1}whatever strays too close. 405 00:25:30,833 --> 00:25:35,000 {\an1}And as our black hole's mass and influence grows, 406 00:25:35,033 --> 00:25:38,833 its surroundings are changing, too. 407 00:25:38,866 --> 00:25:43,533 ♪ ♪ 408 00:25:45,766 --> 00:25:49,366 {\an1}The sea of stars and gas around the black hole 409 00:25:49,400 --> 00:25:52,433 {\an1}continues to grow... 410 00:25:54,133 --> 00:25:58,766 {\an1}...gradually evolving into the familiar spiral disk 411 00:25:58,800 --> 00:26:02,333 we call home: 412 00:26:02,366 --> 00:26:06,400 {\an1}the majestic Milky Way with the supermassive 413 00:26:06,433 --> 00:26:10,266 {\an1}Sagittarius A-star at its core. 414 00:26:19,566 --> 00:26:21,000 KAVIRAJ: So when Sagittarius A-star 415 00:26:21,033 --> 00:26:23,200 {\an1}becomes a supermassive black hole, 416 00:26:23,233 --> 00:26:25,933 {\an7}it really comes of age, and it acquires the ability 417 00:26:25,966 --> 00:26:28,233 {\an7}to have a transformational impact 418 00:26:28,266 --> 00:26:31,266 on the evolution of the entire galaxy. 419 00:26:31,300 --> 00:26:34,400 DOELEMAN: Black holes are the ultimate engines in the universe. 420 00:26:34,433 --> 00:26:36,500 {\an1}When you think about a car, 421 00:26:36,533 --> 00:26:38,333 the first thing you're interested in is, 422 00:26:38,366 --> 00:26:39,700 {\an1}how does it work? 423 00:26:39,733 --> 00:26:43,400 {\an1}You open the hood and you look at the engine of the car. 424 00:26:43,433 --> 00:26:45,900 {\an1}With a black hole, you're asking, 425 00:26:45,933 --> 00:26:48,966 {\an1}"I want to lift the hood up on an entire galaxy. 426 00:26:49,000 --> 00:26:52,600 {\an1}How does a galaxy power itself at its very heart?" 427 00:26:52,633 --> 00:26:57,766 ♪ ♪ 428 00:27:00,433 --> 00:27:02,666 NARRATOR: The center of the young galaxy 429 00:27:02,700 --> 00:27:06,600 {\an1}is rich with swirling gas and dust: 430 00:27:06,633 --> 00:27:10,866 {\an1}more offerings to feast on. 431 00:27:15,366 --> 00:27:20,333 ♪ ♪ 432 00:27:20,366 --> 00:27:23,700 {\an1}This is a gluttonous period, 433 00:27:23,733 --> 00:27:28,466 a new era for Sagittarius A-star... 434 00:27:30,400 --> 00:27:36,333 {\an1}...when the invisible giant has the power to sculpt the galaxy. 435 00:27:36,366 --> 00:27:40,566 ♪ ♪ 436 00:27:41,766 --> 00:27:44,766 WHITTAM: As Sagittarius A-star is gorging on food, 437 00:27:44,800 --> 00:27:46,966 the food that it's waiting to eat 438 00:27:47,000 --> 00:27:50,100 {\an1}is swirling around the central supermassive black hole 439 00:27:50,133 --> 00:27:53,400 in this violent, energetic disk, 440 00:27:53,433 --> 00:27:59,100 {\an1}and the matter is ripped apart by the gravity, 441 00:27:59,133 --> 00:28:01,433 {\an1}which causes the protons and electrons to then make 442 00:28:01,466 --> 00:28:04,100 these twisted magnetic field lines. 443 00:28:04,133 --> 00:28:05,866 OLUSEYI: Everything is rotating and orbiting, 444 00:28:05,900 --> 00:28:08,500 {\an8}so at the center of this black hole, 445 00:28:08,533 --> 00:28:09,700 {\an7}this accretion disk, 446 00:28:09,733 --> 00:28:12,633 {\an8}you have a twisted magnetic field, 447 00:28:12,666 --> 00:28:14,566 {\an1}almost like a tornado. 448 00:28:14,600 --> 00:28:16,166 ARCAND: Right before material 449 00:28:16,200 --> 00:28:18,900 {\an7}approaches that event horizon-- that, 450 00:28:18,933 --> 00:28:21,366 {\an7}that eternal prison, if you will-- 451 00:28:21,400 --> 00:28:25,233 {\an7}it can be redirected instead. 452 00:28:25,266 --> 00:28:27,333 NARRATOR: And from the blazing tumult, 453 00:28:27,366 --> 00:28:29,566 {\an1}the super-heated material 454 00:28:29,600 --> 00:28:32,666 is thrown out along the magnetic poles... 455 00:28:34,266 --> 00:28:40,600 {\an1}...two high-powered jets launched out into the cosmos. 456 00:28:40,633 --> 00:28:42,833 {\an1}They can reach hundreds of thousands of light-years 457 00:28:42,866 --> 00:28:44,100 {\an1}from the black hole itself. 458 00:28:47,466 --> 00:28:50,866 NARRATOR: It's only recently that we've begun to grasp 459 00:28:50,900 --> 00:28:55,466 {\an1}the huge influence of Sagittarius A-star on our galaxy 460 00:28:55,500 --> 00:28:58,800 {\an1}and the role that those super-powered jets 461 00:28:58,833 --> 00:29:00,366 may have played. 462 00:29:00,400 --> 00:29:02,000 {\an8}MAN: Engines start. 463 00:29:02,033 --> 00:29:05,300 {\an7}One, zero, lift-off. 464 00:29:08,533 --> 00:29:12,866 {\an1}The Delta rocket carrying a gamma ray telescope 465 00:29:12,900 --> 00:29:17,466 {\an1}searching for unseen physics in the stars of the galaxies. 466 00:29:19,500 --> 00:29:24,400 ♪ ♪ 467 00:29:26,066 --> 00:29:29,100 NARRATOR: Just over a decade ago, 468 00:29:29,133 --> 00:29:34,900 {\an1}astronomers made a completely unexpected discovery. 469 00:29:34,933 --> 00:29:36,400 {\an8}It was this whole piece of our galaxy 470 00:29:36,433 --> 00:29:39,233 {\an7}that we never knew was there before. 471 00:29:39,266 --> 00:29:41,633 {\an7}It would be like finding a brand-new continent on Earth. 472 00:29:46,133 --> 00:29:50,800 NARRATOR: The Fermi space telescope was built to detect gamma rays, 473 00:29:50,833 --> 00:29:55,066 {\an1}the most energetic radiation in the universe. 474 00:29:55,100 --> 00:29:57,600 FINKBEINER: Fermi is roughly 100 times as sensitive 475 00:29:57,633 --> 00:29:59,800 {\an8}as previous gamma ray telescopes. 476 00:29:59,833 --> 00:30:01,366 {\an7}So it has the sensitivity 477 00:30:01,400 --> 00:30:06,133 {\an1}to see things that we just simply couldn't see before. 478 00:30:06,166 --> 00:30:10,400 NARRATOR: Orbiting the Earth once every 96 minutes, 479 00:30:10,433 --> 00:30:14,266 Fermi constructs a map of the cosmos 480 00:30:14,300 --> 00:30:18,100 and uncovers an invisible landscape-- 481 00:30:18,133 --> 00:30:21,233 {\an1}the most energetic regions of the galaxy 482 00:30:21,266 --> 00:30:25,233 {\an1}highlighted across the sky. 483 00:30:25,266 --> 00:30:27,166 ARCAND: So we pointed the Fermi telescope 484 00:30:27,200 --> 00:30:30,233 {\an1}towards our very own supermassive black hole, 485 00:30:30,266 --> 00:30:34,033 {\an1}and we had a picture of what that area sort of looked like-- 486 00:30:34,066 --> 00:30:34,966 {\an1}in our minds, at least. 487 00:30:35,000 --> 00:30:38,066 But then Fermi revealed something 488 00:30:38,100 --> 00:30:41,233 {\an1}completely astonishing and unexpected. 489 00:30:42,933 --> 00:30:46,533 NARRATOR: Emerging from the plane of the Milky Way 490 00:30:46,566 --> 00:30:49,966 {\an1}are two enormous bubbles, 491 00:30:50,000 --> 00:30:55,900 {\an1}each one stretching 25,000 light-years, 492 00:30:55,933 --> 00:31:00,400 {\an1}together reaching half the width of the galaxy. 493 00:31:02,866 --> 00:31:04,500 FINKBEINER: If you could see in gamma rays, 494 00:31:04,533 --> 00:31:05,966 {\an1}the Fermi bubbles would be about 495 00:31:06,000 --> 00:31:08,100 {\an1}the biggest thing you see on the sky. 496 00:31:08,133 --> 00:31:10,066 {\an7}They look like huge dumbbells 497 00:31:10,100 --> 00:31:11,200 {\an7}going straight up and straight back 498 00:31:11,233 --> 00:31:15,800 {\an1}from the center of the black hole. 499 00:31:15,833 --> 00:31:19,666 NARRATOR: The bubbles match the imprint scientists expect 500 00:31:19,700 --> 00:31:23,200 {\an1}an enormous eruption from Sagittarius A-star 501 00:31:23,233 --> 00:31:27,133 {\an1}to leave on the galaxy. 502 00:31:27,166 --> 00:31:30,500 CROSTON: We had had some clues that the Milky Way might have had 503 00:31:30,533 --> 00:31:33,233 a more energetic and active past, 504 00:31:33,266 --> 00:31:35,600 {\an7}but the incredible thing about the Fermi bubbles 505 00:31:35,633 --> 00:31:39,366 {\an7}was that they suddenly gave us concrete evidence 506 00:31:39,400 --> 00:31:42,266 {\an7}that the Milky Way was much more energetic 507 00:31:42,300 --> 00:31:45,433 {\an7}at some time in its history. 508 00:31:55,833 --> 00:32:00,900 ♪ ♪ 509 00:32:00,933 --> 00:32:04,200 NARRATOR: When our black hole gorges, 510 00:32:04,233 --> 00:32:09,733 {\an1}it unleashes a towering inferno of super-heated matter. 511 00:32:13,366 --> 00:32:14,933 TREMBLAY: A supermassive black hole 512 00:32:14,966 --> 00:32:17,466 {\an7}can impart something like a trillion, 513 00:32:17,500 --> 00:32:19,766 {\an7}trillion atomic bombs' per second 514 00:32:19,800 --> 00:32:21,700 {\an1}worth of energy. 515 00:32:21,733 --> 00:32:24,233 DOELEMAN: If we were to be in the line of fire 516 00:32:24,266 --> 00:32:26,400 {\an7}of one of those jets, 517 00:32:26,433 --> 00:32:27,466 {\an7}it would be catastrophic for us. 518 00:32:27,500 --> 00:32:30,133 {\an1}We'd be vaporized. 519 00:32:30,166 --> 00:32:35,333 ♪ ♪ 520 00:32:44,300 --> 00:32:46,766 NARRATOR: Every planet in the jet's path 521 00:32:46,800 --> 00:32:50,166 {\an1}could have its atmosphere stripped away. 522 00:32:55,566 --> 00:33:00,766 ♪ ♪ 523 00:33:10,433 --> 00:33:12,300 {\an1}But further out in the galaxy... 524 00:33:16,300 --> 00:33:20,466 {\an1}...these violent outbursts from Sagittarius A-star 525 00:33:20,500 --> 00:33:24,033 may have played a surprising role. 526 00:33:24,066 --> 00:33:29,166 (birds chirping) 527 00:33:37,433 --> 00:33:42,466 {\an1}Because the hot gas displaced by the supermassive black hole 528 00:33:42,500 --> 00:33:47,500 {\an1}has a calming effect on the galaxy that hosts it. 529 00:33:47,533 --> 00:33:49,133 HALL: In order for stars to form, 530 00:33:49,166 --> 00:33:52,700 {\an8}you need very cold and very dense gas, 531 00:33:52,733 --> 00:33:55,766 {\an7}because stars form through the collapse of material. 532 00:33:55,800 --> 00:33:58,700 CHADAYAMMURI: So, instead, if you have 533 00:33:58,733 --> 00:34:01,200 something like a supermassive black hole 534 00:34:01,233 --> 00:34:04,100 {\an7}that is sending out these hot jets 535 00:34:04,133 --> 00:34:06,333 {\an7}into the galaxy around it, 536 00:34:06,366 --> 00:34:09,133 {\an7}those jets are going to heat up the gas. 537 00:34:09,166 --> 00:34:11,700 Now the gas is no longer cold enough 538 00:34:11,733 --> 00:34:13,966 to collapse and then form a star. 539 00:34:15,866 --> 00:34:18,266 DOELEMAN: There's a symbiotic relationship 540 00:34:18,300 --> 00:34:20,400 {\an1}between the supermassive black hole at the center 541 00:34:20,433 --> 00:34:23,200 {\an1}and its host galaxy. 542 00:34:23,233 --> 00:34:25,666 {\an1}And this relationship determines 543 00:34:25,700 --> 00:34:28,466 {\an1}the rate at which stars form, planets form, 544 00:34:28,500 --> 00:34:31,300 {\an1}and ultimately, in some sense, 545 00:34:31,333 --> 00:34:32,566 why we are here. 546 00:34:32,600 --> 00:34:37,733 ♪ ♪ 547 00:34:46,066 --> 00:34:51,200 ♪ ♪ 548 00:34:53,166 --> 00:34:55,500 NARRATOR: After spending billions of years 549 00:34:55,533 --> 00:35:01,166 {\an1}consuming the gas, dust, and stars around it, 550 00:35:01,200 --> 00:35:04,566 {\an1}there is little left to feast on. 551 00:35:08,866 --> 00:35:12,433 {\an1}Our black hole falls dormant. 552 00:35:14,766 --> 00:35:20,733 {\an1}Today, the Milky Way has entered an era of calm 553 00:35:20,766 --> 00:35:25,266 {\an1}and Sagittarius A-star is a sleeping giant, 554 00:35:25,300 --> 00:35:29,633 {\an1}the enormous bubbles spotted by the Fermi telescope 555 00:35:29,666 --> 00:35:32,466 {\an1}echoes of a lively past. 556 00:35:32,500 --> 00:35:34,033 FINKBEINER: You never want to assume that 557 00:35:34,066 --> 00:35:36,666 {\an1}you live at a special time in the history of the universe. 558 00:35:36,700 --> 00:35:39,733 {\an1}But it is kind of a special time 559 00:35:39,766 --> 00:35:41,800 that, right now, the black hole is very quiet, 560 00:35:41,833 --> 00:35:43,533 {\an1}and it must have been much more active 561 00:35:43,566 --> 00:35:47,366 {\an1}a few million years ago. 562 00:35:51,333 --> 00:35:53,300 NARRATOR: As our understanding has grown, 563 00:35:53,333 --> 00:35:57,533 {\an1}our picture of black holes has transformed, 564 00:35:57,566 --> 00:36:01,100 {\an1}no longer sinister monsters, 565 00:36:01,133 --> 00:36:03,900 but agents of change and creation. 566 00:36:03,933 --> 00:36:07,733 {\an1}Sculptors of the cosmos. 567 00:36:07,766 --> 00:36:09,033 ROSARIO: We are far from 568 00:36:09,066 --> 00:36:11,600 {\an7}unlocking all the secrets 569 00:36:11,633 --> 00:36:13,766 {\an8}of our galaxy's supermassive black hole. 570 00:36:13,800 --> 00:36:16,366 And in fact, the stuff that remains 571 00:36:16,400 --> 00:36:18,500 is probably the most interesting: 572 00:36:18,533 --> 00:36:22,633 {\an1}what happens inside a supermassive black hole 573 00:36:22,666 --> 00:36:25,666 {\an1}and at its event horizon. 574 00:36:30,533 --> 00:36:34,433 HAWKING: Black holes challenge the most basic principle 575 00:36:34,466 --> 00:36:38,066 {\an1}about the predictability of the universe 576 00:36:38,100 --> 00:36:40,966 {\an1}and the certainty of history. 577 00:36:41,000 --> 00:36:43,600 ♪ ♪ 578 00:36:43,633 --> 00:36:47,333 {\an1}Nothing could get out of a black hole. 579 00:36:47,366 --> 00:36:49,533 {\an1}Or so it was thought. 580 00:36:54,233 --> 00:36:55,466 NARRATOR: Black holes are where 581 00:36:55,500 --> 00:37:01,600 {\an1}two of our greatest theories collide and clash. 582 00:37:01,633 --> 00:37:04,633 DOELEMAN: So you've got these two primal forces in the universe: 583 00:37:04,666 --> 00:37:08,933 {\an1}gravity, which we all understand and feel with our bones. 584 00:37:08,966 --> 00:37:10,766 {\an1}And then you've got quantum mechanics, 585 00:37:10,800 --> 00:37:13,966 which governs the theory of the ultra-small, 586 00:37:14,000 --> 00:37:15,833 how atoms and nuclei come together. 587 00:37:15,866 --> 00:37:18,000 The black hole 588 00:37:18,033 --> 00:37:21,533 {\an1}is where gravity and quantum mechanics finally meet. 589 00:37:21,566 --> 00:37:25,266 {\an1}SYLVESTER JAMES GATES, JR.: When we try to take the mathematics of the very large 590 00:37:25,300 --> 00:37:27,066 {\an7}and try to combine that with 591 00:37:27,100 --> 00:37:28,900 {\an7}the mathematics of the very small, 592 00:37:28,933 --> 00:37:31,700 {\an7}instead of matching... 593 00:37:31,733 --> 00:37:32,966 {\an7}They get into a fight. 594 00:37:33,000 --> 00:37:36,900 {\an1}And so we don't have a consistent way to describe both. 595 00:37:38,766 --> 00:37:41,566 NARRATOR: We can begin to probe this deep mystery 596 00:37:41,600 --> 00:37:46,300 {\an1}by investigating the heart of Sagittarius A-star. 597 00:37:50,033 --> 00:37:55,633 {\an1}Scientists have studied dozens of stars in its orbit, 598 00:37:55,666 --> 00:37:59,500 {\an1}some passing just a few billion miles 599 00:37:59,533 --> 00:38:02,300 {\an1}from the event horizon, 600 00:38:02,333 --> 00:38:06,500 a hair's width on galactic scales. 601 00:38:06,533 --> 00:38:11,233 {\an1}And these fly-bys could have catastrophic consequences... 602 00:38:18,066 --> 00:38:20,066 ♪ ♪ 603 00:38:20,100 --> 00:38:25,300 {\an1}...because some of these stars likely have planets in orbit. 604 00:38:28,233 --> 00:38:33,100 Planets that may stray too close. 605 00:38:33,133 --> 00:38:36,266 {\an1}Moths to a flame. 606 00:38:40,600 --> 00:38:43,333 {\an1}Pulled from their parent stars 607 00:38:43,366 --> 00:38:46,100 {\an1}towards the abyss. 608 00:38:46,133 --> 00:38:48,533 TREMBLAY: So imagine you're some alien civilization 609 00:38:48,566 --> 00:38:51,366 {\an7}looking up at your lovely home star, S2, in the sky. 610 00:38:51,400 --> 00:38:55,466 {\an7}And one day, the thing starts wandering closer and closer 611 00:38:55,500 --> 00:38:57,933 to what we call the tidal disruption radius 612 00:38:57,966 --> 00:38:59,133 {\an1}of Sagittarius A-star, 613 00:38:59,166 --> 00:39:03,933 {\an1}this four-million-solar-mass black hole. 614 00:39:03,966 --> 00:39:05,800 WHITTAM: If you fell into a black hole, 615 00:39:05,833 --> 00:39:08,966 {\an7}you'd pass the event horizon, and actually, 616 00:39:09,000 --> 00:39:11,266 {\an8}bizarrely, you'd see nothing. 617 00:39:11,300 --> 00:39:16,533 {\an1}There's no physical barrier, there's no big line in space 618 00:39:16,566 --> 00:39:20,066 saying "point of no return." 619 00:39:20,100 --> 00:39:23,400 {\an1}You would just drift very casually, gently 620 00:39:23,433 --> 00:39:26,566 {\an1}across the event horizon. 621 00:39:27,900 --> 00:39:29,400 NARRATOR: If we could stand on 622 00:39:29,433 --> 00:39:33,666 such a planet and look outwards, 623 00:39:33,700 --> 00:39:37,100 {\an1}we'd see something spectacular. 624 00:39:37,133 --> 00:39:43,166 ♪ ♪ 625 00:39:43,200 --> 00:39:46,100 OLUSEYI: You would see a distorted universe, 626 00:39:46,133 --> 00:39:49,400 {\an8}and in fact, you'd see it distorted 627 00:39:49,433 --> 00:39:53,366 {\an1}in both time and space. 628 00:39:53,400 --> 00:39:55,500 WHITTAM: You'd see it playing out 629 00:39:55,533 --> 00:39:59,200 {\an1}at an amazingly fast speed. 630 00:39:59,233 --> 00:40:02,166 {\an1}The rest of time would play out unbelievably fast 631 00:40:02,200 --> 00:40:04,166 {\an1}in front of your eyes. 632 00:40:04,200 --> 00:40:06,933 ♪ ♪ 633 00:40:06,966 --> 00:40:11,033 NARRATOR: But eventually, tidal and gravitational forces 634 00:40:11,066 --> 00:40:14,066 {\an1}become too strong... 635 00:40:14,100 --> 00:40:17,300 ♪ ♪ 636 00:40:17,333 --> 00:40:22,466 {\an1}...stretching space and everything in it. 637 00:40:22,500 --> 00:40:24,533 WHITTAM: Your feet would be pulled 638 00:40:24,566 --> 00:40:26,166 {\an1}more strongly by gravity than your head, 639 00:40:26,200 --> 00:40:30,333 {\an1}so you'd be stretched out into a giant string, 640 00:40:30,366 --> 00:40:34,833 {\an1}and eventually, you'd be one long string one atom thick. 641 00:40:34,866 --> 00:40:39,466 {\an7}We call this spaghettification. 642 00:40:39,500 --> 00:40:42,800 {\an8}NARRATOR: Boulders become rocks. 643 00:40:42,833 --> 00:40:44,700 {\an7}Rocks become sand, 644 00:40:44,733 --> 00:40:47,266 {\an8}whose very atoms 645 00:40:47,300 --> 00:40:52,433 {\an7}are then pulled apart. 646 00:40:52,466 --> 00:40:57,166 {\an8}Gravity and the quantum world collide. 647 00:40:57,200 --> 00:41:00,966 {\an7}Ahead, the heart of the black hole-- 648 00:41:01,000 --> 00:41:04,233 {\an8}the singularity, 649 00:41:04,266 --> 00:41:08,533 {\an7}where all journeys in terminate. 650 00:41:08,566 --> 00:41:09,900 OLUSEYI: Our idea of a singularity 651 00:41:09,933 --> 00:41:11,633 {\an1}is that everything is compressed 652 00:41:11,666 --> 00:41:14,700 {\an1}beyond what it can be until it's nothing, 653 00:41:14,733 --> 00:41:16,700 {\an1}but yet still exists. 654 00:41:16,733 --> 00:41:18,900 That is... 655 00:41:18,933 --> 00:41:21,666 (blows out): Wow. 656 00:41:35,033 --> 00:41:37,400 ♪ ♪ 657 00:41:44,533 --> 00:41:46,300 NARRATOR: Over trillions of years, 658 00:41:46,333 --> 00:41:49,433 {\an1}all the stars around Sagittarius A-star 659 00:41:49,466 --> 00:41:53,266 {\an1}will gradually fade out of existence. 660 00:41:55,966 --> 00:42:01,166 ♪ ♪ 661 00:42:04,933 --> 00:42:08,466 KAVIRAJ: Long after the last-ever sun sets on any planet, 662 00:42:08,500 --> 00:42:10,400 {\an7}black holes will continue to roam the universe. 663 00:42:10,433 --> 00:42:14,533 ♪ ♪ 664 00:42:17,633 --> 00:42:20,433 NARRATOR: The final dark age. 665 00:42:26,566 --> 00:42:27,766 TREMBLAY: If nothing can ever escape, 666 00:42:27,800 --> 00:42:30,066 {\an1}if this is some eternal prison, 667 00:42:30,100 --> 00:42:31,866 {\an1}is that the end of the story? 668 00:42:35,300 --> 00:42:37,166 NARRATOR: Perhaps not. 669 00:42:37,200 --> 00:42:40,400 {\an1}Because scientists now believe that even 670 00:42:40,433 --> 00:42:43,133 {\an1}Sagittarius A-star will die. 671 00:42:48,500 --> 00:42:52,266 And its death will come at the hands of 672 00:42:52,300 --> 00:42:55,633 {\an1}what might seem an inconsequential effect 673 00:42:55,666 --> 00:42:59,400 first described almost five decades ago. 674 00:43:00,766 --> 00:43:02,233 CHRIS DONE: So in 1975, 675 00:43:02,266 --> 00:43:05,600 {\an8}Stephen Hawking published this amazing paper 676 00:43:05,633 --> 00:43:11,033 {\an7}showing that black holes aren't absolutely, completely black. 677 00:43:11,066 --> 00:43:14,300 {\an1}They glow very, very faintly. 678 00:43:14,333 --> 00:43:19,000 {\an1}They have a temperature associated with them. 679 00:43:19,033 --> 00:43:21,933 {\an1}And you can write that temperature 680 00:43:21,966 --> 00:43:27,633 {\an1}very simply in an equation 681 00:43:27,666 --> 00:43:29,033 {\an1}that's just beautiful. 682 00:43:29,066 --> 00:43:32,200 {\an7}It links together so many different parts of physics. 683 00:43:32,233 --> 00:43:33,600 {\an7}It's got gravity in it. 684 00:43:33,633 --> 00:43:36,033 {\an1}It's got the mass of the black hole in it. 685 00:43:36,066 --> 00:43:38,000 {\an1}It's got the speed of light. 686 00:43:38,033 --> 00:43:40,933 {\an1}It's got constants relating to atomic physics, 687 00:43:40,966 --> 00:43:42,433 {\an8}the microworld. 688 00:43:42,466 --> 00:43:45,900 {\an8}And it's putting all of these together 689 00:43:45,933 --> 00:43:47,733 {\an1}and giving us a temperature. 690 00:43:47,766 --> 00:43:51,166 NARRATOR: Hawking's equation has huge implications 691 00:43:51,200 --> 00:43:53,800 for the future of the black hole. 692 00:43:53,833 --> 00:43:56,100 {\an8}So if something has a temperature, 693 00:43:56,133 --> 00:43:58,200 {\an7}it's glowing, it's radiating. 694 00:43:58,233 --> 00:44:00,200 {\an7}Like when you put your hand close to a fire, 695 00:44:00,233 --> 00:44:01,166 {\an8}you can feel it. 696 00:44:01,200 --> 00:44:03,933 {\an1}And that losing energy, 697 00:44:03,966 --> 00:44:06,933 {\an1}for a black hole like Sagittarius A-star, 698 00:44:06,966 --> 00:44:09,800 over timescales that are hugely long, 699 00:44:09,833 --> 00:44:14,166 {\an1}it's going to evaporate away. 700 00:44:14,200 --> 00:44:17,000 {\an1}It's going to disappear. 701 00:44:17,033 --> 00:44:21,366 ♪ ♪ 702 00:44:30,233 --> 00:44:32,333 {\an8}NARRATOR: Very gradually, 703 00:44:32,366 --> 00:44:34,433 {\an7}this Hawking radiation 704 00:44:34,466 --> 00:44:39,900 {\an8}will erode away Sagittarius A-star 705 00:44:39,933 --> 00:44:44,300 {\an1}until, many trillions and trillions of years 706 00:44:44,333 --> 00:44:46,633 {\an1}into the future... 707 00:44:53,233 --> 00:44:56,333 {\an1}...in a final burst of light... 708 00:45:01,033 --> 00:45:06,533 {\an1}...our black hole will disappear. 709 00:45:06,566 --> 00:45:10,133 {\an1}And then the Milky Way will be completely dark 710 00:45:10,166 --> 00:45:13,333 {\an1}for all eternity. 711 00:45:15,866 --> 00:45:17,233 DONE: So why does it matter 712 00:45:17,266 --> 00:45:19,133 {\an1}if these black holes disintegrate 713 00:45:19,166 --> 00:45:22,133 {\an1}in the far distant future? 714 00:45:22,166 --> 00:45:25,800 {\an1}Well, the discovery of Hawking radiation 715 00:45:25,833 --> 00:45:28,966 raised some profound questions in physics. 716 00:45:29,000 --> 00:45:32,066 {\an7}If I was to set fire to this piece of paper 717 00:45:32,100 --> 00:45:35,366 {\an7}with Stephen Hawking's equation written on it... 718 00:45:37,333 --> 00:45:40,433 {\an7}...what happens to all that information as it burns away, 719 00:45:40,466 --> 00:45:42,666 {\an7}as it radiates away? 720 00:45:42,700 --> 00:45:49,000 {\an8}Do we lose it from the universe forever? 721 00:46:00,033 --> 00:46:05,266 {\an1}Maybe if I could sweep up all the ash, 722 00:46:05,300 --> 00:46:09,200 {\an1}if I could find all the photons 723 00:46:09,233 --> 00:46:12,233 {\an1}and reconstruct them, 724 00:46:12,266 --> 00:46:16,300 {\an1}maybe I could reconstruct that piece of paper, 725 00:46:16,333 --> 00:46:20,366 {\an1}even the equation written on it. 726 00:46:20,400 --> 00:46:23,366 {\an1}So does this also apply to black holes? 727 00:46:23,400 --> 00:46:26,700 What happened to all the information 728 00:46:26,733 --> 00:46:28,733 {\an1}contained on all the material 729 00:46:28,766 --> 00:46:30,700 {\an1}that ever fell into a black hole? 730 00:46:30,733 --> 00:46:36,266 {\an1}And as a black hole evaporates, what happens to it? 731 00:46:42,100 --> 00:46:46,733 {\an8}HAWKING: Black holes ain't as black as they are painted. 732 00:46:46,766 --> 00:46:51,266 {\an7}They are not the eternal prisons they were once thought. 733 00:46:54,533 --> 00:47:00,333 {\an1}So if you feel you are in a black hole, don't give up. 734 00:47:03,533 --> 00:47:06,400 {\an1}There's a way out. 735 00:47:12,466 --> 00:47:16,733 NARRATOR: If information somehow escapes from Sagittarius A-star 736 00:47:16,766 --> 00:47:18,766 {\an1}as it evaporates away, 737 00:47:18,800 --> 00:47:22,933 {\an1}the implication is profound. 738 00:47:22,966 --> 00:47:26,466 {\an1}Scientists now believe that every star, 739 00:47:26,500 --> 00:47:28,500 asteroid, 740 00:47:28,533 --> 00:47:29,833 planet-- 741 00:47:29,866 --> 00:47:34,366 {\an1}everything that ever fell into Sagittarius A-star-- 742 00:47:34,400 --> 00:47:37,400 may live on, 743 00:47:37,433 --> 00:47:39,666 {\an1}every aspect and position 744 00:47:39,700 --> 00:47:45,133 {\an1}of every particle encoded as information. 745 00:47:46,600 --> 00:47:48,933 {\an1}All that you would theoretically need 746 00:47:48,966 --> 00:47:52,066 {\an1}to put the whole back together. 747 00:47:54,066 --> 00:47:56,500 {\an8}So the memory of every single thing 748 00:47:56,533 --> 00:47:58,533 {\an7}that's "fallen into," become part of, 749 00:47:58,566 --> 00:48:00,166 {\an7}Sagittarius A-star in the Milky Way 750 00:48:00,200 --> 00:48:01,200 {\an7}hasn't been lost. 751 00:48:01,233 --> 00:48:02,733 {\an1}It's still there. 752 00:48:02,766 --> 00:48:05,600 It's just that we can't access that now. 753 00:48:05,633 --> 00:48:10,200 {\an1}But maybe we might be able to read the ashes of that memory 754 00:48:10,233 --> 00:48:13,333 {\an1}in the far future of the universe. 755 00:48:13,366 --> 00:48:18,400 NARRATOR: But how can anything escape a black hole's grip? 756 00:48:18,433 --> 00:48:20,400 PONTZEN: The defining fact of a black hole 757 00:48:20,433 --> 00:48:22,866 is that nothing should be able to get out. 758 00:48:22,900 --> 00:48:25,633 {\an7}And yet when you look at Hawking radiation, 759 00:48:25,666 --> 00:48:28,433 {\an7}it seems to be suggesting that quantum physics 760 00:48:28,466 --> 00:48:32,633 {\an7}does connect up the inside back to the outside. 761 00:48:32,666 --> 00:48:37,566 {\an1}We just don't really know how. 762 00:48:37,600 --> 00:48:39,933 NARRATOR: Black holes force us to 763 00:48:39,966 --> 00:48:45,466 {\an1}consider nature in entirely new and mind-bending ways. 764 00:48:45,500 --> 00:48:48,433 DELILAH GATES: People aren't at all certain about the resolution 765 00:48:48,466 --> 00:48:51,866 {\an7}to what happens when we throw things into black holes, 766 00:48:51,900 --> 00:48:52,966 {\an8}as far as where the information goes. 767 00:48:53,000 --> 00:48:54,300 {\an7}It's still an open question. 768 00:48:54,333 --> 00:48:57,000 {\an7}Maybe it gets sent to a portal to another dimension, 769 00:48:57,033 --> 00:48:59,966 {\an1}maybe it gets pumped into some other branch 770 00:49:00,000 --> 00:49:02,700 {\an1}of a larger multiverse. 771 00:49:02,733 --> 00:49:04,666 {\an7}Some people imagine that black holes are really 772 00:49:04,700 --> 00:49:08,266 {\an1}just a kind of quantum fuzz, a fuzzball. 773 00:49:08,300 --> 00:49:10,300 DOELEMAN: Some people think that all the information 774 00:49:10,333 --> 00:49:11,600 {\an1}that fell into the black hole 775 00:49:11,633 --> 00:49:13,333 {\an7}is somehow encoded on its surface 776 00:49:13,366 --> 00:49:15,500 in a hologram. 777 00:49:15,533 --> 00:49:18,366 RICHARD ANANTUA: But we're not really privy to any of this information. 778 00:49:18,400 --> 00:49:20,633 {\an7}And if we want to find out, we'd have to go in. 779 00:49:22,666 --> 00:49:25,333 NARRATOR: Whatever the solution proves to be, 780 00:49:25,366 --> 00:49:27,133 {\an1}it will have ramifications 781 00:49:27,166 --> 00:49:30,900 far beyond the black hole itself. 782 00:49:30,933 --> 00:49:33,866 ♪ ♪ 783 00:49:33,900 --> 00:49:38,366 MINGARELLI: This theory of quantum gravity that's so elusive right now, 784 00:49:38,400 --> 00:49:40,200 {\an1}that is what we would need to describe 785 00:49:40,233 --> 00:49:43,333 {\an8}what's happening inside black holes, 786 00:49:43,366 --> 00:49:45,666 {\an8}could either be the most exciting development 787 00:49:45,700 --> 00:49:50,400 {\an7}to happen in the next decade or maybe even the next century, 788 00:49:50,433 --> 00:49:53,900 {\an1}or it could be an alarm bell going off in our heads 789 00:49:53,933 --> 00:49:56,300 that maybe Einstein's theory of gravity 790 00:49:56,333 --> 00:50:00,533 is not the final word on gravity. 791 00:50:00,566 --> 00:50:03,166 NARRATOR: Solving the mystery of black holes 792 00:50:03,200 --> 00:50:07,833 {\an1}may be our best chance to complete the picture of nature 793 00:50:07,866 --> 00:50:11,133 {\an1}that has eluded us for the last century. 794 00:50:11,166 --> 00:50:12,333 KAVIRAJ: So perhaps the important thing 795 00:50:12,366 --> 00:50:14,700 {\an7}isn't what the answer turns out to be. 796 00:50:14,733 --> 00:50:16,800 {\an7}The important thing is that we will gain 797 00:50:16,833 --> 00:50:18,600 {\an7}a fuller understanding of the cosmos 798 00:50:18,633 --> 00:50:20,066 {\an8}by studying these remarkable objects. 799 00:50:20,100 --> 00:50:24,866 {\an7}Studying the universe has completely changed our universe. 800 00:50:24,900 --> 00:50:28,700 {\an7}We have to rethink everything over and over again. 801 00:50:28,733 --> 00:50:31,233 {\an1}Like, it's almost, like, tear up the universe we know 802 00:50:31,266 --> 00:50:35,100 {\an1}and write a new one. 803 00:50:35,133 --> 00:50:37,200 NARRATOR: We're still a long way from 804 00:50:37,233 --> 00:50:42,166 {\an1}fully comprehending the secrets of black holes, 805 00:50:42,200 --> 00:50:45,133 {\an1}but we're beginning to lift the veil. 806 00:50:48,466 --> 00:50:52,233 Far from being mere cosmic aberrations, 807 00:50:52,266 --> 00:50:57,833 {\an1}black holes fundamentally shape our universe. 808 00:50:59,766 --> 00:51:01,066 {\an1}So it's extraordinary to think that 809 00:51:01,100 --> 00:51:02,566 we might be fundamentally connected 810 00:51:02,600 --> 00:51:04,500 {\an1}to something that we didn't know existed 811 00:51:04,533 --> 00:51:06,966 {\an1}for the vast span of human history. 812 00:51:07,000 --> 00:51:10,400 ♪ ♪ 813 00:51:10,433 --> 00:51:12,166 OLUSEYI: The beautiful thing about black holes 814 00:51:12,200 --> 00:51:14,566 {\an1}is that they're such a rich source of information. 815 00:51:14,600 --> 00:51:17,466 {\an1}We've learned so much about the universe 816 00:51:17,500 --> 00:51:19,166 {\an1}from studying black holes: 817 00:51:19,200 --> 00:51:20,800 space, time, 818 00:51:20,833 --> 00:51:23,266 {\an1}the very fundamental nature of reality. 819 00:51:24,633 --> 00:51:26,966 NARRATOR: Bit by bit revealing 820 00:51:27,000 --> 00:51:30,833 {\an1}the deepest mysteries of the cosmos. 821 00:51:30,866 --> 00:51:34,300 PONTZEN: We're in a golden age of discovery about black holes. 822 00:51:34,333 --> 00:51:36,266 {\an1}We understand how they merge, 823 00:51:36,300 --> 00:51:38,866 we've discovered their colossal jets, 824 00:51:38,900 --> 00:51:40,533 {\an1}and we're beginning to see them 825 00:51:40,566 --> 00:51:44,433 {\an1}not just as destroyers, but also as creators 826 00:51:44,466 --> 00:51:46,800 and sculptors. 827 00:51:46,833 --> 00:51:49,966 And all that is just the beginning. 828 00:51:50,000 --> 00:51:51,866 SMETHURST: Our story's happening now, 829 00:51:51,900 --> 00:51:55,000 but black holes, they're going to outlive us 830 00:51:55,033 --> 00:51:57,200 {\an1}by trillions of years. 831 00:51:57,233 --> 00:52:00,566 Their story is just getting started. 832 00:52:02,633 --> 00:52:06,066 ♪ ♪ 833 00:52:28,133 --> 00:52:32,366 {\an8}♪ ♪ 834 00:52:32,400 --> 00:52:34,366 {\an8}ALOK PATEL: Discover the science behind the news 835 00:52:34,400 --> 00:52:36,500 {\an7}with the "NOVA Now" podcast. 836 00:52:36,533 --> 00:52:39,933 {\an7}Listen at pbs.org/novanowpodcast 837 00:52:39,966 --> 00:52:43,933 {\an7}or wherever you find your favorite podcasts. 838 00:52:43,966 --> 00:52:47,266 {\an8}ANNOUNCER: To order the five-part "NOVA: Universe Revealed" on DVD, 839 00:52:47,300 --> 00:52:51,466 {\an8}visit ShopPBS or call 1-800-PLAY-PBS. 840 00:52:51,500 --> 00:52:56,200 {\an7}Also available with PBS Passport and on Amazon Prime Video. 841 00:52:56,233 --> 00:53:02,400 {\an8}♪ ♪ 842 00:53:07,300 --> 00:53:11,600 {\an8}♪ ♪