1 00:00:01,827 --> 00:00:04,827 --Captions by VITAC-- www.vitac.com 2 00:00:04,827 --> 00:00:07,793 CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS 3 00:00:07,793 --> 00:00:15,758 ♪♪ 4 00:00:15,758 --> 00:00:17,448 [ CLOCK TICKING ] 5 00:00:17,448 --> 00:00:21,655 Narrator: TIME -- WE THINK OF IT AS REGULAR AS CLOCKWORK... 6 00:00:24,068 --> 00:00:29,758 ...TICKING OUT THE STEADY PROGRESS OF THE UNIVERSE. 7 00:00:29,758 --> 00:00:33,620 BUT TIME IS NOT CONSTANT. 8 00:00:33,620 --> 00:00:37,482 AND THAT HOLDS THE KEY TO THE SECRETS OF CREATION. 9 00:00:39,275 --> 00:00:42,965 AND THE TWO PEOPLE WHO HELPED US UNLOCK THOSE MYSTERIES 10 00:00:42,965 --> 00:00:46,310 ARE JOINED BY A COSMIC COINCIDENCE OF TIMING. 11 00:00:46,310 --> 00:00:51,448 ♪♪ 12 00:00:51,448 --> 00:00:54,586 ON MARCH 14, 1879, 13 00:00:54,586 --> 00:00:59,206 ALBERT EINSTEIN WAS BORN IN ULM, GERMANY. 14 00:00:59,206 --> 00:01:02,103 AND ON MARCH 14, 2018, 15 00:01:02,103 --> 00:01:07,206 STEPHEN HAWKING DIED IN CAMBRIDGE, ENGLAND. 16 00:01:07,206 --> 00:01:10,310 THEY ARE UNDOUBTEDLY THE MOST RECOGNIZED SCIENTISTS 17 00:01:10,310 --> 00:01:12,275 IN THE WORLD. 18 00:01:12,275 --> 00:01:15,827 AND BETWEEN THEM, THEY HAVE TRANSFORMED OUR UNDERSTANDING 19 00:01:15,827 --> 00:01:18,413 OF EVERYTHING. 20 00:01:18,413 --> 00:01:24,344 ♪♪ 21 00:01:24,344 --> 00:01:28,413 Man: IF ALBERT EINSTEIN HAD NOT LIVED, 22 00:01:28,413 --> 00:01:31,448 IT IS HARD TO IMAGINE 23 00:01:31,448 --> 00:01:35,034 WHAT THE 20th CENTURY WOULD'VE BEEN LIKE. 24 00:01:35,034 --> 00:01:36,931 Narrator: IN THE EARLY 1900s, 25 00:01:36,931 --> 00:01:40,689 ALBERT EINSTEIN DEVELOPED AN IDEA SO REVOLUTIONARY 26 00:01:40,689 --> 00:01:44,896 IT CHANGED THE COURSE OF HISTORY. 27 00:01:44,896 --> 00:01:47,448 IT WAS CALLED RELATIVITY. 28 00:01:49,827 --> 00:01:52,896 Oluseyi: MANY OF EINSTEIN'S IDEAS ARE OUT THERE. 29 00:01:52,896 --> 00:01:54,931 AT BEST, THEY'RE COUNTERINTUITIVE. 30 00:01:54,931 --> 00:01:58,482 OTHERS ARE SIMPLY MIND-BENDING. 31 00:01:58,482 --> 00:01:59,793 [ TRAIN WHISTLE BLOWS ] 32 00:01:59,793 --> 00:02:02,448 Narrator: IN THE FIRST PROGRAM, 33 00:02:02,448 --> 00:02:06,620 WE SAW HOW EINSTEIN DISCOVERED THAT TIME APPEARS TO SLOW DOWN 34 00:02:06,620 --> 00:02:09,034 ON MOVING OBJECTS... 35 00:02:12,034 --> 00:02:16,000 ...STRETCHING SO MUCH THAT AT CLOSE TO THE SPEED OF LIGHT, 36 00:02:16,000 --> 00:02:19,758 A DAY CAN APPEAR TO LAST 20,000 YEARS. 37 00:02:21,689 --> 00:02:25,517 HOW HE REALIZED THE UNIVERSE IS MADE OF A FLEXIBLE FABRIC 38 00:02:25,517 --> 00:02:28,103 OF SPACE AND TIME. 39 00:02:30,379 --> 00:02:32,655 THAT THE FORCE OF GRAVITY IS CREATED 40 00:02:32,655 --> 00:02:35,137 BY THE DISTORTION OF THIS SPACE-TIME 41 00:02:35,137 --> 00:02:37,793 BY STARS AND PLANETS. 42 00:02:39,862 --> 00:02:43,241 AND HOW THOSE DISCOVERIES INSPIRED STEPHEN HAWKING 43 00:02:43,241 --> 00:02:45,379 TO DEVELOP EINSTEIN'S IDEAS 44 00:02:45,379 --> 00:02:47,896 TO REVEAL THE MOST EXTRAORDINARY PHENOMENA 45 00:02:47,896 --> 00:02:50,827 IN THE UNIVERSE. 46 00:02:50,827 --> 00:02:53,379 Hawking: BLACK HOLES ARE STRANGER THAN ANYTHING 47 00:02:53,379 --> 00:02:56,931 DREAMED UP BY SCIENCE-FICTION WRITERS, 48 00:02:56,931 --> 00:03:02,758 BUT THEY ARE FIRMLY MATTERS OF SCIENCE FACT. 49 00:03:02,758 --> 00:03:06,000 Levin: HAWKING IS INCREDIBLY INNOVATIVE, 50 00:03:06,000 --> 00:03:12,413 ABLE TO MAKE DISCOVERIES THAT SEEMED TOTALLY COUNTERINTUITIVE 51 00:03:12,413 --> 00:03:14,344 AND TOTALLY IMPOSSIBLE. 52 00:03:14,344 --> 00:03:20,344 ♪♪ 53 00:03:20,344 --> 00:03:21,931 Narrator: IN THIS PROGRAM, 54 00:03:21,931 --> 00:03:24,103 WE WILL DISCOVER HOW EINSTEIN'S THEORIES 55 00:03:24,103 --> 00:03:26,482 HAVE BEEN DEVELOPED TO GIVE US THE POWER 56 00:03:26,482 --> 00:03:29,241 TO UNDERSTAND CREATION... 57 00:03:29,241 --> 00:03:32,517 Paramesvaran: THE POINT OF THE LHC IS TO TRY AND UNDERSTAND 58 00:03:32,517 --> 00:03:36,103 HOW THE UNIVERSE CAME INTO ITS CURRENT STATE 59 00:03:36,103 --> 00:03:38,275 FROM THE BIG BANG. 60 00:03:41,862 --> 00:03:45,413 Narrator: ...OR TO UNLEASH UNIMAGINABLE DESTRUCTION. 61 00:03:47,068 --> 00:03:50,655 AND THAT'S THE POWER OF E=MC2. 62 00:03:50,655 --> 00:03:53,862 Narrator: AND HOW RIGHT UP TO HIS DEATH, 63 00:03:53,862 --> 00:03:56,413 STEPHEN HAWKING WAS REDEFINING 64 00:03:56,413 --> 00:03:58,896 OUR UNDERSTANDING OF THE UNIVERSE. 65 00:03:58,896 --> 00:04:03,655 Strominger: HE SAID HE HADN'T BEEN THIS EXCITED IN 40 YEARS. 66 00:04:03,655 --> 00:04:07,000 WHEN I MISS HIM THE MOST IS WHEN WE FIGURE SOMETHING OUT. 67 00:04:07,000 --> 00:04:09,413 I'D LIKE TO TELL HIM. 68 00:04:09,413 --> 00:04:14,689 ♪♪ 69 00:04:14,689 --> 00:04:18,655 Narrator: THIS IS THE STORY OF HOW THESE TWO REMARKABLE SCIENTISTS 70 00:04:18,655 --> 00:04:22,344 SHOWED US THAT THE UNIVERSE IS STRANGER AND MORE WONDERFUL 71 00:04:22,344 --> 00:04:24,275 THAN WE EVER IMAGINED. 72 00:04:24,275 --> 00:04:31,310 ♪♪ 73 00:04:31,310 --> 00:04:38,344 ♪♪ 74 00:04:38,344 --> 00:04:41,862 [ RADIO TELESCOPES BEEPING ] 75 00:04:41,862 --> 00:04:45,379 IN THE 1960s, RADIO TELESCOPES AROUND THE WORLD 76 00:04:45,379 --> 00:04:51,241 STARTED TO PICK UP STRANGE SIGNALS FROM OUTER SPACE. 77 00:04:51,241 --> 00:04:56,034 THEY APPEAR TO BE COMING FROM TINY OBJECTS OF MASSIVE DENSITY, 78 00:04:56,034 --> 00:04:58,379 NEUTRON STARS. 79 00:04:58,379 --> 00:05:01,413 THESE MYSTERIOUS OBJECTS HAD BEEN PREDICTED 80 00:05:01,413 --> 00:05:04,689 BY EINSTEIN'S THEORY OF RELATIVITY, 81 00:05:04,689 --> 00:05:07,689 AND THEIR DISCOVERY MEANT OTHER PREDICTIONS OF RELATIVITY 82 00:05:07,689 --> 00:05:11,379 MIGHT ALSO EXIST -- 83 00:05:11,379 --> 00:05:15,758 OBJECTS LIKE BLACK HOLES. 84 00:05:15,758 --> 00:05:19,655 UNDERSTANDING THESE MYSTERIOUS MONSTERS OF THE UNIVERSE 85 00:05:19,655 --> 00:05:23,241 KICKSTARTED THE CAREERS OF A YOUNG GROUP OF PHYSICISTS, 86 00:05:23,241 --> 00:05:25,965 INCLUDING STEPHEN HAWKING. 87 00:05:25,965 --> 00:05:28,689 IT WAS A GOLDEN AGE, RELATIVITY, 88 00:05:28,689 --> 00:05:34,517 AS WE STARTED OUT UNDER HAWKING'S LEADERSHIP, 89 00:05:34,517 --> 00:05:37,551 THE THEORY OF BLACK HOLES. 90 00:05:37,551 --> 00:05:42,862 ♪♪ 91 00:05:42,862 --> 00:05:48,172 ♪♪ 92 00:05:48,172 --> 00:05:50,068 Narrator: IT SOON BECAME CLEAR 93 00:05:50,068 --> 00:05:53,931 THAT BLACK HOLES WERE VERY PECULIAR PLACES. 94 00:05:53,931 --> 00:05:59,379 ♪♪ 95 00:05:59,379 --> 00:06:04,896 ♪♪ 96 00:06:04,896 --> 00:06:07,379 WE THINK OF A BLACK HOLE AS A THING, AS AN OBJECT, 97 00:06:07,379 --> 00:06:09,931 BUT REALLY, IT'S A REGION OF SPACE-TIME. 98 00:06:09,931 --> 00:06:11,724 A BLACK HOLE IS A REGION OF SPACE-TIME 99 00:06:11,724 --> 00:06:13,689 WHERE GRAVITY IS SO STRONG 100 00:06:13,689 --> 00:06:15,482 THAT ONCE YOU ENTER THAT REGION, 101 00:06:15,482 --> 00:06:18,931 YOU JUST CANNOT EVER LEAVE IT. 102 00:06:18,931 --> 00:06:20,758 Narrator: BLACK HOLES ARE FISSURES 103 00:06:20,758 --> 00:06:23,586 IN THE FABRIC OF THE UNIVERSE. 104 00:06:23,586 --> 00:06:25,896 SURROUNDED BY AN INVISIBLE BOUNDARY 105 00:06:25,896 --> 00:06:28,379 CALLED THE EVENT HORIZON, 106 00:06:28,379 --> 00:06:32,310 NOTHING THAT CROSSES THAT HORIZON CAN EVER GET AWAY. 107 00:06:33,965 --> 00:06:36,241 Hawking: FALLING THROUGH THE EVENT HORIZON 108 00:06:36,241 --> 00:06:41,241 IS A BIT LIKE GOING OVER NIAGARA FALLS IN A CANOE. 109 00:06:41,241 --> 00:06:43,172 IF YOU ARE ABOVE THE FALLS, 110 00:06:43,172 --> 00:06:47,206 YOU CAN GET AWAY IF YOU PADDLE FAST ENOUGH. 111 00:06:47,206 --> 00:06:53,103 BUT ONCE YOU ARE OVER THE EDGE, YOU ARE LOST. 112 00:06:53,103 --> 00:06:56,793 Levin: THE BLACK HOLE IS REALLY DEFINED BY THAT EVENT HORIZON. 113 00:06:56,793 --> 00:07:00,000 IT SEPARATES US, FUNDAMENTALLY AND FOREVER, 114 00:07:00,000 --> 00:07:01,724 FROM THE INSIDE OF THE BLACK HOLE. 115 00:07:01,724 --> 00:07:04,620 YOU CAN FALL IN, BUT YOU CANNOT COME OUT. 116 00:07:04,620 --> 00:07:06,689 Narrator: THE CONSEQUENCE IS -- 117 00:07:06,689 --> 00:07:09,103 ONCE SOMETHING HAS FALLEN INTO A BLACK HOLE, 118 00:07:09,103 --> 00:07:12,137 IT APPEARS TO BE LOST FROM THE UNIVERSE FOREVER. 119 00:07:13,827 --> 00:07:15,275 Hawking: FROM THE OUTSIDE, 120 00:07:15,275 --> 00:07:19,137 YOU CAN'T TELL WHAT IS INSIDE A BLACK HOLE. 121 00:07:19,137 --> 00:07:22,931 YOU CAN THROW TELEVISION SETS, DIAMOND RINGS, 122 00:07:22,931 --> 00:07:27,000 OR YOUR WORST ENEMIES INTO A BLACK HOLE, 123 00:07:27,000 --> 00:07:29,241 AND ALL THE BLACK HOLE WILL REMEMBER 124 00:07:29,241 --> 00:07:32,620 IS THE TOTAL MASS AND THE STATE OF ROTATION. 125 00:07:36,310 --> 00:07:38,000 ♪♪ 126 00:07:38,000 --> 00:07:40,310 Narrator: IT WAS THESE MONSTERS THAT STEPHEN HAWKING 127 00:07:40,310 --> 00:07:46,275 WAS WORKING ON IN CAMBRIDGE IN THE MID-1970s. 128 00:07:46,275 --> 00:07:50,103 AND IN 1974, HE MADE AN ENORMOUS BREAKTHROUGH. 129 00:07:52,344 --> 00:07:57,034 Hawking: UP TO 1974, EVERYONE, INCLUDING ME, 130 00:07:57,034 --> 00:08:01,827 THOUGHT THAT NOTHING COULD GET OUT OF A BLACK HOLE. 131 00:08:01,827 --> 00:08:05,206 THEN I DISCOVERED THAT THE UNCERTAINTY PRINCIPLE 132 00:08:05,206 --> 00:08:10,310 OF QUANTUM MECHANICS ALLOWED PARTICLES TO LEAP OUT. 133 00:08:12,586 --> 00:08:14,241 BY ADDING QUANTUM MECHANICS, 134 00:08:14,241 --> 00:08:18,103 HAWKING MADE THE STUNNING DISCOVERY 135 00:08:18,103 --> 00:08:21,758 THAT, ACTUALLY, BLACK HOLES COULD EVAPORATE. 136 00:08:21,758 --> 00:08:23,586 BLACK HOLES ARE NOT WHAT YOU THOUGHT THEY WERE. 137 00:08:23,586 --> 00:08:25,379 BLACK HOLES CAN ACTUALLY RADIATE. 138 00:08:25,379 --> 00:08:27,413 YEAH, THAT WAS AN IN-YOUR-FACE, 139 00:08:27,413 --> 00:08:31,482 SHOCKING IDEA THAT HE PUT FORWARD. 140 00:08:31,482 --> 00:08:35,655 Hawking: QUANTUM MECHANICS IMPLIES THAT THE WHOLE OF SPACE 141 00:08:35,655 --> 00:08:38,413 IS FILLED WITH PAIRS OF VIRTUAL PARTICLES 142 00:08:38,413 --> 00:08:40,655 AND ANTIPARTICLES 143 00:08:40,655 --> 00:08:44,724 THAT ARE CONSTANTLY MATERIALIZING IN PAIRS 144 00:08:44,724 --> 00:08:47,689 AND ANNIHILATING EACH OTHER. 145 00:08:47,689 --> 00:08:50,344 NOW, IN THE PRESENCE OF A BLACK HOLE, 146 00:08:50,344 --> 00:08:53,034 ONE MEMBER OF A PAIR OF VIRTUAL PARTICLES 147 00:08:53,034 --> 00:08:55,448 MAY FALL INTO THE HOLE, 148 00:08:55,448 --> 00:08:58,724 LEAVING THE OTHER MEMBER WITHOUT A PARTNER. 149 00:08:58,724 --> 00:09:01,896 AS PARTICLES ESCAPE FROM A BLACK HOLE, 150 00:09:01,896 --> 00:09:06,241 THE HOLE WILL LOSE MASS AND SHRINK. 151 00:09:06,241 --> 00:09:12,965 EVENTUALLY, THE BLACK HOLE WILL LOSE ALL ITS MASS AND DISAPPEAR. 152 00:09:12,965 --> 00:09:17,206 ♪♪ 153 00:09:17,206 --> 00:09:21,310 Narrator: THE DISCOVERY THAT BLACK HOLES EMITTED PARTICLES 154 00:09:21,310 --> 00:09:24,931 WAS SOON NAMED HAWKING RADIATION. 155 00:09:24,931 --> 00:09:28,000 IT SHOWED THAT BLACK HOLES WERE EVEN STRANGER 156 00:09:28,000 --> 00:09:29,724 THAN WE HAD IMAGINED. 157 00:09:29,724 --> 00:09:32,275 Levin: HOW CAN A BLACK HOLE EVAPORATE? 158 00:09:32,275 --> 00:09:36,310 IT SEEMED SO PECULIAR AND VERY COUNTERINTUITIVE, 159 00:09:36,310 --> 00:09:38,172 BUT IT MADE SENSE. 160 00:09:38,172 --> 00:09:40,689 THE CALCULATIONS WERE CHECKED OVER AND OVER AGAIN, 161 00:09:40,689 --> 00:09:41,862 AND IT MADE SENSE. 162 00:09:41,862 --> 00:09:44,172 THIS IS COMPLETELY COUNTER TO EVERYTHING 163 00:09:44,172 --> 00:09:46,620 WE THOUGHT THAT WE UNDERSTOOD ABOUT BLACK HOLES 164 00:09:46,620 --> 00:09:48,310 IN THE YEAR 1970. 165 00:09:48,310 --> 00:09:52,172 ♪♪ 166 00:09:52,172 --> 00:09:56,000 Narrator: BY COMBINING GENERAL RELATIVITY WITH QUANTUM MECHANICS, 167 00:09:56,000 --> 00:10:00,068 HAWKING HAD SHOWN THE ENDURING POWER OF EINSTEIN'S THEORY. 168 00:10:00,068 --> 00:10:05,931 ♪♪ 169 00:10:05,931 --> 00:10:08,310 BUT AS EINSTEIN HIMSELF WOULD DISCOVER, 170 00:10:08,310 --> 00:10:11,344 THAT THEORY ALSO HAD A DARK SIDE. 171 00:10:11,344 --> 00:10:15,413 IT COULD BE USED TO UNLEASH DEVASTATION ON THE EARTH. 172 00:10:15,413 --> 00:10:23,344 ♪♪ 173 00:10:23,344 --> 00:10:25,034 Narrator: BACK IN THE 1920s, 174 00:10:25,034 --> 00:10:27,379 EINSTEIN FOUND THAT INTEREST IN HIS WORK 175 00:10:27,379 --> 00:10:31,172 HAD EXTENDED BEYOND THE WORLD OF THEORETICAL PHYSICS 176 00:10:31,172 --> 00:10:34,310 AND INTO THE REALM OF POPULIST POLITICS. 177 00:10:34,310 --> 00:10:37,172 [ CROWD CHANTING "SIEG HEIL!" ] 178 00:10:37,172 --> 00:10:40,827 ♪♪ 179 00:10:40,827 --> 00:10:43,344 Kaiser: LONG BEFORE THERE WAS EVEN A FORMAL NAZI PARTY, 180 00:10:43,344 --> 00:10:46,655 AS EARLY AS SPRING OF 1920, 181 00:10:46,655 --> 00:10:50,482 THERE WERE RALLIES TO DENOUNCE NOT JUST ALBERT EINSTEIN, 182 00:10:50,482 --> 00:10:53,379 BUT RATHER, TO DENOUNCE GENERAL RELATIVITY. 183 00:10:53,379 --> 00:10:56,620 THEY WOULD RENT OUT SPORTS ARENAS AND OPERA HOUSES 184 00:10:56,620 --> 00:10:58,517 AND LARGE, LARGE STADIUMS -- 185 00:10:58,517 --> 00:11:00,482 THOUSANDS OF PEOPLE IN ATTENDANCE -- 186 00:11:00,482 --> 00:11:03,448 TO BASICALLY CHANT, "DOWN WITH WARPING SPACE-TIME." 187 00:11:04,931 --> 00:11:07,517 IT WAS SEEN AS A SYMBOL OF ALL THAT HAD GONE WRONG 188 00:11:07,517 --> 00:11:09,241 WITH SO-CALLED JEWISH PHYSICS. 189 00:11:11,068 --> 00:11:13,827 IT BECAME CLEAR IT WAS NOT GONNA BE SAFE FOR HIM. 190 00:11:15,758 --> 00:11:18,310 Narrator: AFTER THE NAZIS CAME TO POWER, 191 00:11:18,310 --> 00:11:23,000 EINSTEIN FLED GERMANY IN 1933 192 00:11:23,000 --> 00:11:26,034 AND SETTLED HERE, IN PRINCETON, NEW JERSEY, 193 00:11:26,034 --> 00:11:28,517 WORKING AT THE INSTITUTE FOR ADVANCED STUDY. 194 00:11:30,827 --> 00:11:32,896 AND AS A LIFELONG PACIFIST, 195 00:11:32,896 --> 00:11:36,517 HE WAS APPALLED AT THE PROSPECT OF ANOTHER WAR, 196 00:11:36,517 --> 00:11:39,172 ESPECIALLY SINCE HE KNEW HIS OWN WORK 197 00:11:39,172 --> 00:11:43,137 COULD HAVE A DEVASTATING IMPACT ON ITS OUTCOME. 198 00:11:43,137 --> 00:11:46,448 EINSTEIN DID NOT WANT TO GET THAT INVOLVED IN THE WAR EFFORT. 199 00:11:46,448 --> 00:11:48,965 I THINK EVERYONE WAS EXTREMELY SURPRISED 200 00:11:48,965 --> 00:11:52,068 THAT THIS 1905 PAPER -- E=MC2 -- 201 00:11:52,068 --> 00:11:55,137 COULD HAVE AN IMPLICATION FOR KILLING PEOPLE. 202 00:11:56,827 --> 00:12:01,275 SO, WE COME TO EINSTEIN'S MOST FAMOUS EQUATION -- 203 00:12:01,275 --> 00:12:05,793 E=MC2. 204 00:12:05,793 --> 00:12:07,482 AND LIKE MANY OF HIS EQUATIONS, 205 00:12:07,482 --> 00:12:10,586 IT HAS THIS MAGICAL PROPERTY OF EQUATING TWO THINGS 206 00:12:10,586 --> 00:12:13,068 THAT YOU WOULDN'T EXPECT TO BE EQUAL. 207 00:12:13,068 --> 00:12:16,000 ON THE LEFT-HAND SIDE, WE FIND "E," THE ENERGY. 208 00:12:16,000 --> 00:12:18,689 ON THE RIGHT-HAND SIDE, "M," THE MASS. 209 00:12:18,689 --> 00:12:21,448 AND SO THIS EQUATION TELLS US THAT ENERGY AND MASS 210 00:12:21,448 --> 00:12:22,931 ARE ESSENTIALLY THE SAME. 211 00:12:22,931 --> 00:12:25,586 THEY'RE EQUIVALENT. THEY CAN BE EXCHANGED. 212 00:12:25,586 --> 00:12:28,379 AND THE EXCHANGE RATE IS "C" SQUARED. 213 00:12:28,379 --> 00:12:29,965 "C" IS THE SPEED OF LIGHT. 214 00:12:29,965 --> 00:12:34,000 IT'S HUGE. SO "C" SQUARED IS A TREMENDOUSLY LARGE NUMBER. 215 00:12:34,000 --> 00:12:36,000 SO, ONE WAY TO READ THE EQUATION 216 00:12:36,000 --> 00:12:38,931 IS THAT A HUGE AMOUNT OF ENERGY CAN BE CONVERTED 217 00:12:38,931 --> 00:12:41,137 INTO A SMALL AMOUNT OF MATTER. 218 00:12:41,137 --> 00:12:44,413 BUT READING THE EQUATION FROM THE OPPOSITE END, 219 00:12:44,413 --> 00:12:47,310 IT TELLS US THAT A SMALL AMOUNT OF MATTER 220 00:12:47,310 --> 00:12:50,655 CAN BE CONVERTED INTO A HUGE AMOUNT OF ENERGY. 221 00:12:50,655 --> 00:12:56,793 ♪♪ 222 00:12:56,793 --> 00:13:03,034 ♪♪ 223 00:13:03,034 --> 00:13:07,206 Narrator: THE POWER OF E=MC2 WENT FAR BEYOND THE THEORETICAL. 224 00:13:09,896 --> 00:13:11,689 IN THE EARLY 1920s, 225 00:13:11,689 --> 00:13:13,827 EINSTEIN'S FRIEND ARTHUR EDDINGTON 226 00:13:13,827 --> 00:13:15,896 REALIZED THAT THIS FAMOUS EQUATION 227 00:13:15,896 --> 00:13:19,344 WAS THE SECRET TO HOW STARS, LIKE OUR SUN, 228 00:13:19,344 --> 00:13:22,965 PRODUCE SUCH VAST AMOUNTS OF HEAT AND LIGHT. 229 00:13:25,931 --> 00:13:27,655 Oluseyi: DEEP IN THE HEARTS OF STARS, 230 00:13:27,655 --> 00:13:29,724 PRESSURES AND TEMPERATURES ARE SO HIGH 231 00:13:29,724 --> 00:13:32,965 THAT HYDROGEN NUCLEI SLAM INTO EACH OTHER, FUSING, 232 00:13:32,965 --> 00:13:37,103 AND EVENTUALLY CREATING HELIUM NUCLEI. 233 00:13:37,103 --> 00:13:39,931 AND IN THAT PROCESS, A TINY AMOUNT OF MASS 234 00:13:39,931 --> 00:13:41,793 IS CONVERTED INTO ENERGY. 235 00:13:44,517 --> 00:13:47,137 ALBERT EINSTEIN REALIZED THAT, PERHAPS, 236 00:13:47,137 --> 00:13:49,241 WE COULD HARNESS THAT PROCESS HERE ON EARTH 237 00:13:49,241 --> 00:13:50,724 AND CREATE ENERGY OF OUR OWN. 238 00:13:50,724 --> 00:13:53,310 ♪♪ 239 00:13:53,310 --> 00:13:55,517 OR CREATE A WEAPON. 240 00:13:55,517 --> 00:14:02,068 ♪♪ 241 00:14:02,068 --> 00:14:03,275 Narrator: WORRIED THE GERMANS 242 00:14:03,275 --> 00:14:06,448 HAD ALREADY STARTED A NUCLEAR PROGRAM, 243 00:14:06,448 --> 00:14:09,931 EINSTEIN AND FELLOW PHYSICIST LEO SZILARD 244 00:14:09,931 --> 00:14:14,862 WROTE TO PRESIDENT ROOSEVELT, URGING HIM TO DEVELOP A BOMB. 245 00:14:14,862 --> 00:14:19,517 ROOSEVELT RESPONDED BY SETTING UP THE MANHATTAN PROJECT. 246 00:14:19,517 --> 00:14:21,275 ♪♪ 247 00:14:21,275 --> 00:14:24,724 THEY ACHIEVED THEIR GOAL IN JUST THREE YEARS. 248 00:14:24,724 --> 00:14:28,344 ♪♪ 249 00:14:28,344 --> 00:14:30,620 Oluseyi: THIS IS THE TRINITY MONUMENT. 250 00:14:30,620 --> 00:14:33,793 ON JULY 16, 1945, 251 00:14:33,793 --> 00:14:36,586 THE WORLD'S VERY FIRST NUCLEAR BOMB 252 00:14:36,586 --> 00:14:40,103 WAS SET OFF RIGHT HERE IN THIS SPOT. 253 00:14:40,103 --> 00:14:42,172 THE BOMB, NICKNAMED "GADGET," 254 00:14:42,172 --> 00:14:44,310 WAS WINCHED TO THE TOP OF A 100-FOOT TOWER 255 00:14:44,310 --> 00:14:47,413 THAT STOOD RIGHT HERE. 256 00:14:47,413 --> 00:14:51,482 THE OBSERVERS RETREATED AND, JUST BEFORE DAWN, 257 00:14:51,482 --> 00:14:53,275 THE BOMB WAS DETONATED. 258 00:14:53,275 --> 00:14:57,344 [ EXPLOSION ] 259 00:14:57,344 --> 00:14:59,068 AT 5:29 A.M., 260 00:14:59,068 --> 00:15:01,517 THE DEVICE EXPLODED WITH AN ENERGY EQUIVALENT 261 00:15:01,517 --> 00:15:03,517 TO 20 KILOTONS OF TNT. 262 00:15:03,517 --> 00:15:06,172 [ EXPLOSION ] 263 00:15:06,172 --> 00:15:11,379 THE ROAR OF THE SHOCK WAVE WAS FELT OVER 100 MILES AWAY. 264 00:15:11,379 --> 00:15:12,758 THE SURROUNDING MOUNTAINS 265 00:15:12,758 --> 00:15:16,344 WERE ILLUMINATED BRIGHTER THAN DAYTIME 266 00:15:16,344 --> 00:15:21,724 AND THE MUSHROOM CLOUD REACHED 7 1/2 MILES IN HEIGHT. 267 00:15:21,724 --> 00:15:25,068 ALL THAT POWER WAS RELEASED WHEN, INSIDE THE BOMB, 268 00:15:25,068 --> 00:15:30,137 JUST 0.9 GRAMS OF MATTER WERE CONVERTED INTO ENERGY. 269 00:15:30,137 --> 00:15:33,448 AND THAT'S THE POWER OF E=MC2. 270 00:15:33,448 --> 00:15:36,310 ♪♪ 271 00:15:36,310 --> 00:15:38,206 Narrator: JUST THREE WEEKS LATER, 272 00:15:38,206 --> 00:15:41,586 ON AUGUST 6, 1945, 273 00:15:41,586 --> 00:15:43,344 ANOTHER BOMB WAS DROPPED, 274 00:15:43,344 --> 00:15:45,862 OVER THE JAPANESE CITY OF HIROSHIMA. 275 00:15:48,931 --> 00:15:51,551 AT EXACTLY 8:15 IN THE MORNING, 276 00:15:51,551 --> 00:15:56,275 0.6 GRAMS OF MATTER WAS CONVERTED INTO ENERGY, 277 00:15:56,275 --> 00:15:59,172 INCINERATING 70,000 PEOPLE. 278 00:15:59,172 --> 00:16:04,448 ♪♪ 279 00:16:04,448 --> 00:16:06,517 [ EXPLOSION ] 280 00:16:06,517 --> 00:16:09,586 THE DEVASTATING POWER OF EINSTEIN'S EQUATION 281 00:16:09,586 --> 00:16:11,275 HAD BEEN UNLEASHED. 282 00:16:11,275 --> 00:16:12,827 ♪♪ 283 00:16:12,827 --> 00:16:15,068 NOW, IT'S ALWAYS BEEN A MIXED LEGACY 284 00:16:15,068 --> 00:16:16,448 FOR THE HISTORY OF PHYSICS, RIGHT? 285 00:16:16,448 --> 00:16:17,620 LIKE, WE LIKE TO THINK OF OURSELVES 286 00:16:17,620 --> 00:16:19,137 AS DISCOVERING SECRETS OF THE UNIVERSE, 287 00:16:19,137 --> 00:16:20,724 NOT AS BLOWING THINGS UP. 288 00:16:20,724 --> 00:16:22,793 BUT THERE IS THIS NECESSARY INTERPLAY 289 00:16:22,793 --> 00:16:24,586 BETWEEN THE DISCOVERIES WE MAKE 290 00:16:24,586 --> 00:16:26,172 AND THE TECHNOLOGICAL CAPABILITIES 291 00:16:26,172 --> 00:16:28,827 THAT WE HAVE HERE ON EARTH THAT PHYSICISTS HAVE TO ACCEPT. 292 00:16:28,827 --> 00:16:30,862 AND, OF COURSE, EINSTEIN ALWAYS HAD MIXED FEELINGS 293 00:16:30,862 --> 00:16:33,517 ABOUT IT LATER ON, 'CAUSE HE WAS, AT HEART, A PACIFIST. 294 00:16:33,517 --> 00:16:37,310 ♪♪ 295 00:16:37,310 --> 00:16:39,172 Narrator: FOR THE REST OF HIS LIFE, 296 00:16:39,172 --> 00:16:43,379 EINSTEIN CAMPAIGNED FOR NUCLEAR DISARMAMENT AND PEACE. 297 00:16:43,379 --> 00:16:46,827 ♪♪ 298 00:17:06,103 --> 00:17:11,000 ♪♪ 299 00:17:11,000 --> 00:17:14,000 THE NUCLEAR BOMB WAS A DEVASTATING DEMONSTRATION 300 00:17:14,000 --> 00:17:16,448 OF HOW EINSTEIN'S THEORIES COULD BE USED 301 00:17:16,448 --> 00:17:17,724 TO PRACTICAL EFFECT. 302 00:17:17,724 --> 00:17:23,965 ♪♪ 303 00:17:23,965 --> 00:17:26,655 EVER SINCE THEN, HUMANITY HAS BEEN BUILDING 304 00:17:26,655 --> 00:17:29,517 INCREASINGLY COMPLICATED MACHINES 305 00:17:29,517 --> 00:17:32,862 THAT USE EINSTEIN'S THEORY, NOT FOR DESTRUCTION, 306 00:17:32,862 --> 00:17:35,724 BUT TO UNLOCK THE MYSTERIES OF THE UNIVERSE. 307 00:17:35,724 --> 00:17:44,620 ♪♪ 308 00:17:44,620 --> 00:17:49,000 ♪♪ 309 00:17:49,000 --> 00:17:53,586 THIS IS THE ENTRANCE TO THE LARGE HADRON COLLIDER. 310 00:17:53,586 --> 00:17:56,655 BURIED DEEP BELOW THE SWISS-FRENCH BORDER, 311 00:17:56,655 --> 00:17:59,034 IT IS THE WORLD'S BIGGEST MACHINE. 312 00:17:59,034 --> 00:18:03,241 ♪♪ 313 00:18:03,241 --> 00:18:05,655 SUDAN PARAMESVARAN IS A SCIENTIST 314 00:18:05,655 --> 00:18:09,344 WHO USES THE LHC TO TRAVEL BACK IN TIME. 315 00:18:09,344 --> 00:18:14,344 ♪♪ 316 00:18:14,344 --> 00:18:17,793 Paramesvaran: THE POINT OF THE LHC IS TO TRY AND UNDERSTAND 317 00:18:17,793 --> 00:18:20,620 HOW THE UNIVERSE CAME INTO ITS CURRENT STATE 318 00:18:20,620 --> 00:18:24,344 FROM THE BIG BANG ALL THOSE BILLIONS OF YEARS AGO, 319 00:18:24,344 --> 00:18:26,310 AND ONE WAY THAT WE CAN DO THAT IS 320 00:18:26,310 --> 00:18:29,655 TO TRY AND RECREATE SOME OF THOSE EARLY CONDITIONS. 321 00:18:29,655 --> 00:18:33,551 Narrator: SUDAN'S WORK RELIES ON THE CONCEPT OF TIME DILATION 322 00:18:33,551 --> 00:18:36,103 DEVELOPED BY ALBERT EINSTEIN. 323 00:18:36,103 --> 00:18:40,931 TIME DILATION IS ONLY NOTICEABLE AT CLOSE TO THE SPEED OF LIGHT, 324 00:18:40,931 --> 00:18:44,448 BUT IN THE LHC, WE CAN SEE IT IN ACTION. 325 00:18:44,448 --> 00:18:47,758 BEAMS OF PROTONS ARE FIRED THROUGH THESE TUBES 326 00:18:47,758 --> 00:18:51,482 AND SMASHED INTO EACH OTHER AT VERY HIGH SPEED. 327 00:18:51,482 --> 00:18:52,655 Paramesvaran: IN THE MIDDLE OF THIS PIPE 328 00:18:52,655 --> 00:18:55,172 IS WHERE THE ACTUAL PROTONS ARE TRAVELING. 329 00:18:55,172 --> 00:18:58,931 WE ACCELERATE THEM USING VERY POWERFUL MAGNETS. 330 00:18:58,931 --> 00:19:00,724 THEY'RE ACTUALLY TRAVELING ROUND THE RING 331 00:19:00,724 --> 00:19:02,965 11,000 TIMES A SECOND, 332 00:19:02,965 --> 00:19:04,965 VERY, VERY CLOSE TO THE SPEED OF LIGHT. 333 00:19:04,965 --> 00:19:07,034 ♪♪ 334 00:19:07,034 --> 00:19:10,344 SO WHEN THE PROTONS COLLIDE, THEY ACTUALLY SMASH UP 335 00:19:10,344 --> 00:19:12,275 INTO LOTS OF LITTLE DIFFERENT THINGS. 336 00:19:12,275 --> 00:19:14,275 A LOT OF NEW PARTICLES ARE CREATED. 337 00:19:14,275 --> 00:19:17,379 ♪♪ 338 00:19:17,379 --> 00:19:20,068 Narrator: WE THINK THE PARTICLES CREATED IN THESE COLLISIONS 339 00:19:20,068 --> 00:19:21,965 ARE SIMILAR TO THOSE THAT EXISTED 340 00:19:21,965 --> 00:19:24,689 IN THE MOMENTS AFTER THE BIG BANG. 341 00:19:24,689 --> 00:19:29,344 STUDYING THEM CAN HELP US UNDERSTAND THE EARLY UNIVERSE, 342 00:19:29,344 --> 00:19:33,137 AND THAT'S WHERE TIME DILATION COMES IN. 343 00:19:33,137 --> 00:19:34,724 OKAY, SO WHAT WE HAVE HERE 344 00:19:34,724 --> 00:19:37,310 IS A VISUAL REPRESENTATION OF A COLLISION. 345 00:19:37,310 --> 00:19:39,275 THE PROTONS ARE COLLIDING RIGHT IN THE MIDDLE OF OUR DETECTOR 346 00:19:39,275 --> 00:19:41,724 AND THEN EVERYTHING COMES OUT FROM THAT POINT. 347 00:19:41,724 --> 00:19:43,448 ♪♪ 348 00:19:43,448 --> 00:19:45,551 Narrator: EACH OF THESE TRACKS REPRESENTS 349 00:19:45,551 --> 00:19:48,965 AN INDIVIDUAL PARTICLE CREATED IN THE COLLISIONS. 350 00:19:48,965 --> 00:19:50,655 MANY OF THEM BLINK OUT OF EXISTENCE 351 00:19:50,655 --> 00:19:53,034 IN A FRACTION OF A SECOND. 352 00:19:53,034 --> 00:19:57,482 THIS IS ACTUALLY THE DECAY OF A B MESON. 353 00:19:57,482 --> 00:19:59,137 IT'S TYPICAL LIFETIME IS ONLY 354 00:19:59,137 --> 00:20:01,862 A MILLIONTH OF A MILLIONTH OF A SECOND, SO IT'S TINY, 355 00:20:01,862 --> 00:20:03,586 AND THAT WOULD MAKE IT VERY DIFFICULT FOR US 356 00:20:03,586 --> 00:20:05,206 TO ACTUALLY INVESTIGATE IT. 357 00:20:05,206 --> 00:20:09,241 IT WOULD DECAY VERY CLOSE TO THE PRIMARY POINT, HERE. 358 00:20:09,241 --> 00:20:11,896 NOW, BECAUSE IT'S TRAVELING CLOSE TO THE SPEED OF LIGHT, 359 00:20:11,896 --> 00:20:14,103 ITS CLOCK IS RUNNING A LITTLE BIT SLOWER. 360 00:20:14,103 --> 00:20:16,206 THIS MEANS THAT IT'S ACTUALLY ABLE 361 00:20:16,206 --> 00:20:18,931 TO TRAVEL THIS DISTANCE BEFORE DECAYING. 362 00:20:18,931 --> 00:20:21,724 AND SO THE FACT THAT IT UNDERGOES TIME DILATION 363 00:20:21,724 --> 00:20:23,896 GIVES US AN AVENUE OF PHYSICS TO EXPLORE 364 00:20:23,896 --> 00:20:25,827 WHICH WE OTHERWISE WOULDN'T BE ABLE TO DO. 365 00:20:25,827 --> 00:20:28,137 ♪♪ 366 00:20:28,137 --> 00:20:31,206 Narrator: THE TIME DILATION WE SEE IN THE LHC 367 00:20:31,206 --> 00:20:34,034 IS EINSTEIN'S THEORY OF RELATIVITY IN ACTION. 368 00:20:34,034 --> 00:20:35,896 ♪♪ 369 00:20:35,896 --> 00:20:38,172 THIS TIME, FOR PEACEFUL MEANS. 370 00:20:38,172 --> 00:20:43,448 ♪♪ 371 00:20:43,448 --> 00:20:45,896 WE HAVE ANSWERED MANY MYSTERIES ABOUT THE UNIVERSE 372 00:20:45,896 --> 00:20:47,758 USING EINSTEIN'S THEORIES. 373 00:20:47,758 --> 00:20:53,551 ♪♪ 374 00:20:53,551 --> 00:20:55,827 BUT EVEN IN THE 21st CENTURY, 375 00:20:55,827 --> 00:20:58,413 THERE ARE STILL MORE DISCOVERIES TO BE MADE. 376 00:20:58,413 --> 00:21:07,310 ♪♪ 377 00:21:07,310 --> 00:21:09,965 DISCOVERIES THAT WILL ELEGANTLY TIE TOGETHER 378 00:21:09,965 --> 00:21:12,896 THE WORK OF ALBERT EINSTEIN ON RELATIVITY 379 00:21:12,896 --> 00:21:15,517 AND STEPHEN HAWKING ON BLACK HOLES. 380 00:21:15,517 --> 00:21:20,482 ♪♪ 381 00:21:20,482 --> 00:21:22,241 Hawking: BLACK HOLES ARE STRANGER 382 00:21:22,241 --> 00:21:25,551 THAN ANYTHING DREAMED UP BY SCIENCE FICTION WRITERS... 383 00:21:25,551 --> 00:21:27,758 ♪♪ 384 00:21:27,758 --> 00:21:30,689 ...BUT THEY ARE FIRMLY MATTERS OF SCIENCE FACT. 385 00:21:30,689 --> 00:21:35,517 ♪♪ 386 00:21:35,517 --> 00:21:38,586 Narrator: DESPITE ALL OUR ADVANCES IN TECHNOLOGY, 387 00:21:38,586 --> 00:21:43,724 UNTIL RECENTLY, WE HAD NEVER SEEN A BLACK HOLE 388 00:21:43,724 --> 00:21:45,551 AND IT IS THAT SEARCH, 389 00:21:45,551 --> 00:21:48,448 FOR AN ELUSIVE GLIMPSE OF A BLACK HOLE, 390 00:21:48,448 --> 00:21:52,172 THAT HAS BROUGHT DAN MARRONE TO THE MOUNTAINS OF ARIZONA. 391 00:21:52,172 --> 00:21:56,448 ♪♪ 392 00:21:56,448 --> 00:21:58,137 BLACK HOLES ARE ONE OF THOSE THINGS 393 00:21:58,137 --> 00:22:02,068 THAT I FEEL LIKE EVERYONE IS INTERESTED IN, RIGHT? 394 00:22:02,068 --> 00:22:06,137 THE FACT THAT WE'VE NEVER EVEN SEEN ONE IS KIND OF AMAZING. 395 00:22:06,137 --> 00:22:07,931 WE'RE SO CONFIDENT THEY'RE THERE, 396 00:22:07,931 --> 00:22:10,827 BUT, YET, "SHOW ME A PICTURE," AND YOU CAN'T. 397 00:22:13,344 --> 00:22:15,310 Narrator: DAN IS ON A MISSION TO DO SOMETHING 398 00:22:15,310 --> 00:22:18,068 NO ONE HAS EVER DONE BEFORE -- 399 00:22:18,068 --> 00:22:20,655 TAKE A PICTURE OF A BLACK HOLE. 400 00:22:20,655 --> 00:22:27,931 ♪♪ 401 00:22:27,931 --> 00:22:29,758 ORDINARILY, IT WOULD BE IMPOSSIBLE 402 00:22:29,758 --> 00:22:31,413 TO PHOTOGRAPH A BLACK HOLE, 403 00:22:31,413 --> 00:22:34,758 LIKE PICKING OUT A SHADOW ON AN ALREADY DARK SKY. 404 00:22:34,758 --> 00:22:36,586 ♪♪ 405 00:22:36,586 --> 00:22:39,103 BUT DAN IS HOPING TO CAPTURE A BLACK HOLE 406 00:22:39,103 --> 00:22:42,241 IN A PARTICULAR PHASE OF LIFE -- 407 00:22:42,241 --> 00:22:43,586 WHILE IT IS FEEDING. 408 00:22:43,586 --> 00:22:47,551 ♪♪ 409 00:22:47,551 --> 00:22:50,517 THE GRAVITATIONAL PULL OF BLACK HOLES IS SO STRONG 410 00:22:50,517 --> 00:22:53,482 THAT THEY CAN CONSUME ENTIRE STARS. 411 00:22:53,482 --> 00:22:55,965 ♪♪ 412 00:22:55,965 --> 00:22:58,517 THIS SIMULATION SHOWS WHAT WE THINK HAPPENS 413 00:22:58,517 --> 00:23:00,827 AS A STAR IS RIPPED APART. 414 00:23:00,827 --> 00:23:03,413 ♪♪ 415 00:23:03,413 --> 00:23:06,068 Levin: WHAT YOU SEE IS THE BRIGHT SPLATTER 416 00:23:06,068 --> 00:23:08,827 OF THE DEBRIS FALLING AROUND THE BLACK HOLE 417 00:23:08,827 --> 00:23:10,206 FROM THE NEIGHBORING STAR. 418 00:23:10,206 --> 00:23:14,448 AND IT TURNS OUT, MAYBE EVEN IRONICALLY, 419 00:23:14,448 --> 00:23:18,103 THAT THE DARKEST OBJECTS FUNDAMENTALLY CONCEIVABLE 420 00:23:18,103 --> 00:23:20,551 BECOME THE BRIGHTEST BEACONS IN THE UNIVERSE. 421 00:23:20,551 --> 00:23:22,827 ♪♪ 422 00:23:22,827 --> 00:23:27,344 Narrator: THE EVENT HORIZON WHERE THE WHIRLPOOL IS AT ITS FIERCEST 423 00:23:27,344 --> 00:23:30,413 IS ONE OF THE MOST EXTREME ENVIRONMENTS IN THE UNIVERSE. 424 00:23:30,413 --> 00:23:33,931 ♪♪ 425 00:23:33,931 --> 00:23:35,379 IT IS WHAT DAN AND HIS COLLEAGUES 426 00:23:35,379 --> 00:23:37,344 ARE TRYING TO TAKE A PICTURE OF. 427 00:23:37,344 --> 00:23:40,172 ♪♪ 428 00:23:40,172 --> 00:23:42,620 THIS IS THE SUBMILLIMETER TELESCOPE 429 00:23:42,620 --> 00:23:44,758 ON MOUNT GRAHAM, IN ARIZONA. 430 00:23:44,758 --> 00:23:46,793 ♪♪ 431 00:23:46,793 --> 00:23:51,689 A RADIO TELESCOPE, IT CAN PROBE THE DEPTHS OF THE UNIVERSE 432 00:23:51,689 --> 00:23:53,379 IN BROAD DAYLIGHT. 433 00:23:53,379 --> 00:23:55,482 ♪♪ 434 00:23:55,482 --> 00:23:57,482 WE'D LIKE TO SEE THAT MATERIAL 435 00:23:57,482 --> 00:23:59,793 CIRCLING THE DRAIN AND DISAPPEARING. 436 00:23:59,793 --> 00:24:01,379 WE'D LIKE TO SEE THE LIGHT ITSELF 437 00:24:01,379 --> 00:24:03,793 NOT ESCAPING A SHADOW IN FRONT OF THE BLACK HOLE 438 00:24:03,793 --> 00:24:05,758 WHERE THE LIGHT IS DISAPPEARING INTO IT. 439 00:24:05,758 --> 00:24:08,655 ♪♪ 440 00:24:08,655 --> 00:24:10,620 Narrator: TO FIND HIS BLACK HOLE, 441 00:24:10,620 --> 00:24:14,413 DAN HAS SET HIS SIGHTS ON THE VERY HEART OF GALAXIES. 442 00:24:14,413 --> 00:24:17,517 ♪♪ 443 00:24:17,517 --> 00:24:20,344 ASTRONOMERS HAVE BEEN TRACKING THE MOTION OF THE STARS 444 00:24:20,344 --> 00:24:24,517 AROUND THE CORE OF OURGALAXY FOR MORE THAN 20 YEARS. 445 00:24:24,517 --> 00:24:29,758 ♪♪ 446 00:24:29,758 --> 00:24:31,103 HOW'S THE WEATHER THIS EVENING? 447 00:24:31,103 --> 00:24:32,758 THE WEATHER'S GOOD. 448 00:24:32,758 --> 00:24:36,241 THE ENORMOUSSPEED AT WHICH THEY ARE MOVING SUGGESTS 449 00:24:36,241 --> 00:24:41,310 THAT THEY ARE ORBITING SOMETHING HUGE AND UNSEEN. 450 00:24:41,310 --> 00:24:45,310 THEY BELIEVE IT IS A SUPERMASSIVE BLACK HOLE, 451 00:24:45,310 --> 00:24:47,862 OVER 40 MILLION KILOMETERS ACROSS 452 00:24:47,862 --> 00:24:51,551 AND FOUR MILLION TIMES THE MASS OF OUR SUN. 453 00:24:51,551 --> 00:24:54,655 IT IS KNOWN AS SAGITTARIUS A[STAR]. 454 00:24:54,655 --> 00:24:56,758 ♪♪ 455 00:24:56,758 --> 00:24:58,655 THE EVENT HORIZON AROUND IT 456 00:24:58,655 --> 00:25:01,068 SHOULD BE ONE OF THE BRIGHTEST SPOTS IN THE GALAXY. 457 00:25:01,068 --> 00:25:04,758 ♪♪ 458 00:25:04,758 --> 00:25:08,379 BUT IT IS STILL SO SMALL AND SO FAR AWAY 459 00:25:08,379 --> 00:25:12,103 THAT TO IMAGE IT TAKES THE LARGEST TELESCOPE EVER BUILT. 460 00:25:12,103 --> 00:25:14,344 ♪♪ 461 00:25:14,344 --> 00:25:18,344 SO, RIGHT, NOW THE TELESCOPE'S POINTED AT SAGITTARIUS A[STAR]. 462 00:25:18,344 --> 00:25:21,793 WE HAVE TO LOOK THROUGH THE ENTIRE PLANE OF THE GALAXY 463 00:25:21,793 --> 00:25:24,482 AND SO, IF YOU LOOK WITH A VISIBLE-LIGHT TELESCOPE, 464 00:25:24,482 --> 00:25:26,344 YOU CAN'T ACTUALLY SEE THE BLACK HOLE. 465 00:25:26,344 --> 00:25:28,172 ALL THE DUST IN THE WAY BLOCKS THE LIGHT 466 00:25:28,172 --> 00:25:30,965 AND SO WE HAVE TO DO THIS WITH A RADIO TELESCOPE. 467 00:25:30,965 --> 00:25:32,517 ♪♪ 468 00:25:32,517 --> 00:25:34,172 AND, IN FACT, WE'RE NOT JUST LOOKING WITH ONE, 469 00:25:34,172 --> 00:25:35,862 BUT WE'RE LOOKING WITH A WHOLE ARRAY OF THEM 470 00:25:35,862 --> 00:25:37,241 SCATTERED OVER THE EARTH. 471 00:25:37,241 --> 00:25:38,827 ♪♪ 472 00:25:38,827 --> 00:25:42,724 Narrator: THE EVENT HORIZON TELESCOPE IS A HUGE NETWORK. 473 00:25:42,724 --> 00:25:45,137 AS WELL AS THIS DISH ON MOUNT GRAHAM, 474 00:25:45,137 --> 00:25:48,586 THERE ARE DISHES IN EUROPE, ON HAWAII, IN CHILE, 475 00:25:48,586 --> 00:25:50,379 AND AT THE SOUTH POLE, 476 00:25:50,379 --> 00:25:52,517 ALL OF WHICH ARE SIMULTANEOUSLY 477 00:25:52,517 --> 00:25:54,448 POINTED AT THE SAME TARGET. 478 00:25:54,448 --> 00:25:57,413 ♪♪ 479 00:25:57,413 --> 00:25:59,827 WHEN THE DATA FROM ALL OF THEM IS COMBINED, 480 00:25:59,827 --> 00:26:04,103 IT CREATES A TELESCOPE THE SIZE OF THE EARTH. 481 00:26:04,103 --> 00:26:06,448 BUT THIS TELESCOPE WAS NOT JUST TRYING 482 00:26:06,448 --> 00:26:08,931 TO IMAGE THE CENTER OF OURGALAXY. 483 00:26:08,931 --> 00:26:12,241 THEY HAD ALSO BEEN STUDYING A MUCH LARGER GALAXY, 484 00:26:12,241 --> 00:26:14,620 OVER 50 MILLION LIGHT-YEARS AWAY, 485 00:26:14,620 --> 00:26:17,827 CALLED M87. 486 00:26:17,827 --> 00:26:19,793 AND, IN APRIL 2019, 487 00:26:19,793 --> 00:26:22,137 THEY RELEASED THIS IMAGE -- 488 00:26:22,137 --> 00:26:24,448 THE FIRST VIEW OF A BLACK HOLE 489 00:26:24,448 --> 00:26:28,689 AND THE MATERIAL AROUND IT SPIRALING INTO OBLIVION. 490 00:26:28,689 --> 00:26:31,275 BUT, WHILE THIS IMAGE IS REMARKABLE, 491 00:26:31,275 --> 00:26:34,241 THERE WAS ALREADY ANOTHER TECHNOLOGY THAT COULD DETECT 492 00:26:34,241 --> 00:26:37,137 STEPHEN HAWKING'S BELOVED BLACK HOLES 493 00:26:37,137 --> 00:26:40,103 AND WHICH MAY ANSWER ONE OF THE FINAL GREAT MYSTERIES 494 00:26:40,103 --> 00:26:42,689 OF EINSTEIN'S THEORY OF RELATIVITY. 495 00:26:42,689 --> 00:26:50,000 ♪♪ 496 00:26:50,000 --> 00:26:51,413 [ ELEVATOR CHIMES ] NOW, 497 00:26:51,413 --> 00:26:54,103 THESE ARE OFFICES AT LIGO. 498 00:26:54,103 --> 00:26:56,655 WE CAN USE ANY OF THESE ROOMS, IF YOU WANT. 499 00:26:56,655 --> 00:27:00,793 BUT, IF YOU WANT MY OFFICE, WE'RE HEADING THERE. 500 00:27:00,793 --> 00:27:01,896 [ CHUCKLES ] 501 00:27:01,896 --> 00:27:05,206 ♪♪ 502 00:27:05,206 --> 00:27:07,344 IT'S FULL OF JUNK. [ LAUGHS ] 503 00:27:07,344 --> 00:27:10,793 THIS IS THE OFFICE THEY GIVE EMERITUS OLD PROFESSORS. 504 00:27:10,793 --> 00:27:12,551 THAT'S WHAT THEY GIVE US. -[ LAUGHS ] 505 00:27:12,551 --> 00:27:16,103 SO, A LOT OF MY PAPERS AND JUNK IS ALL AROUND. 506 00:27:16,103 --> 00:27:21,379 ♪♪ 507 00:27:21,379 --> 00:27:24,689 THERE'S A PICTURE OF MY MENTOR RIGHT OVER THERE. 508 00:27:24,689 --> 00:27:28,275 YOU CAN SEE HIM. HIS NAME IS JERROLD ZACHARIAS. 509 00:27:28,275 --> 00:27:31,068 HE'S THE FIRST GUY WHO EVER SAID TO ME 510 00:27:31,068 --> 00:27:33,551 THAT, YOU KNOW, "YOU'RE NOT AS DUMB AS YOU LOOK." 511 00:27:33,551 --> 00:27:34,931 THAT WAS VERY IMPORTANT. 512 00:27:34,931 --> 00:27:37,206 YOU NEED SOMEBODY IN YOUR LIFE TO TELL YOU THAT. 513 00:27:37,206 --> 00:27:38,862 ♪♪ 514 00:27:38,862 --> 00:27:41,448 Narrator: RAINER WEISS, "RAI" TO HIS FRIENDS, 515 00:27:41,448 --> 00:27:46,827 IS NOW A NOBEL PRIZE-WINNING EMERITUS PROFESSOR AT M.I.T. 516 00:27:46,827 --> 00:27:51,344 BUT IN 1967, HE WAS JUST A JUNIOR FACULTY MEMBER 517 00:27:51,344 --> 00:27:53,758 WHO WAS FASCINATED BY A PARTICULAR PIECE 518 00:27:53,758 --> 00:27:57,482 OF EINSTEIN'S THEORY -- 519 00:27:57,482 --> 00:28:00,137 GRAVITATIONAL WAVES. 520 00:28:00,137 --> 00:28:01,827 IN 1916, 521 00:28:01,827 --> 00:28:03,827 EINSTEIN HIMSELF HAD CALCULATED 522 00:28:03,827 --> 00:28:06,931 THAT OBJECTS MOVING THROUGH THE FABRIC OF SPACE-TIME 523 00:28:06,931 --> 00:28:11,793 SHOULDCAUSE IT TO RIPPLE, LIKE WAVES ON A POND. 524 00:28:11,793 --> 00:28:16,034 AT FIRST, EINSTEIN THOUGHT THAT THESE WAVES WOULD BE SO TINY, 525 00:28:16,034 --> 00:28:18,724 THEY WOULD BE IMPOSSIBLE TO MEASURE. 526 00:28:18,724 --> 00:28:22,482 LATER IN LIFE, HE WAS NOT SURE THEY EXISTED AT ALL. 527 00:28:22,482 --> 00:28:25,103 ♪♪ 528 00:28:25,103 --> 00:28:29,689 Einstein: IF YOU ASK ME WHETHER THERE ARE GRAVITATIONAL WAVES OR NOT, 529 00:28:29,689 --> 00:28:32,448 I MUST ANSWER THAT I DON'T KNOW, 530 00:28:32,448 --> 00:28:34,793 BUT IT IS A HIGHLY INTERESTING PROBLEM. 531 00:28:34,793 --> 00:28:38,931 ♪♪ 532 00:28:38,931 --> 00:28:42,344 Narrator: RAI THOUGHT GRAVITATIONAL WAVES DIDEXIST 533 00:28:42,344 --> 00:28:46,241 AND HAS SPENT A LIFETIME TRYING TO FIND THEM. 534 00:28:46,241 --> 00:28:49,620 SO HE CAME UP WITH A SYSTEM THAT COULD POTENTIALLY DETECT 535 00:28:49,620 --> 00:28:53,034 THE MOST MINISCULE WAVES IN SPACE-TIME. 536 00:28:53,034 --> 00:28:57,620 IT WAS CALLED LASER INTERFEROMETRY. 537 00:28:57,620 --> 00:28:59,275 Weiss: SO, HERE'S THE IDEA. 538 00:28:59,275 --> 00:29:02,172 THERE'S A LASER, WHICH IS THIS CYLINDER. 539 00:29:02,172 --> 00:29:03,724 THERE'S SOMETHING CALLED A BEAM SPLITTER, 540 00:29:03,724 --> 00:29:05,068 WHICH DIVIDES THE LIGHT. 541 00:29:05,068 --> 00:29:08,551 ♪♪ 542 00:29:08,551 --> 00:29:10,103 HALF OF THE LIGHT WILL GET REFLECTED 543 00:29:10,103 --> 00:29:12,413 TO A MIRROR THAT'S OVER HERE 544 00:29:12,413 --> 00:29:15,413 AND THEN SENT BACK TO THIS BEAM SPLITTER. 545 00:29:15,413 --> 00:29:17,344 AND THE OTHER HALF HITS THIS MIRROR 546 00:29:17,344 --> 00:29:19,413 AND COMES BACK TO THE BEAM SPLITTER. 547 00:29:19,413 --> 00:29:22,379 THEN, TWO BEAMS WILL HEAD TOWARD A PHOTO DETECTOR, 548 00:29:22,379 --> 00:29:24,896 AND YOU'LL SEE SOMETHING INTERESTING. 549 00:29:24,896 --> 00:29:26,517 NO LIGHT GOES TO THE PHOTO DETECTOR. 550 00:29:26,517 --> 00:29:28,689 LIGHT CANCELS. 551 00:29:28,689 --> 00:29:31,758 NOW WHAT HAPPENS IS YOU CHANGE THE LENGTH ON ONE ARM, 552 00:29:31,758 --> 00:29:32,862 MAKE IT LONGER, 553 00:29:32,862 --> 00:29:35,862 MAKE THE LIGHT SHORTER ON THE OTHER ARM. 554 00:29:35,862 --> 00:29:38,103 YOU SEE LIGHT DOES GO TO THE PHOTO DETECTOR 555 00:29:38,103 --> 00:29:40,448 WHEN THE PATHS ARE NOT EQUAL ANYMORE. 556 00:29:40,448 --> 00:29:42,827 AND THAT, THE FACT THAT LIGHT GOES 557 00:29:42,827 --> 00:29:44,448 THROUGH THE PHOTO DETECTOR HERE 558 00:29:44,448 --> 00:29:46,620 WHEN THE PATHS ARE NO LONGER EQUAL 559 00:29:46,620 --> 00:29:47,862 AND THEY HAVE BEEN DISTURBED 560 00:29:47,862 --> 00:29:49,862 BY THAT GRAVITATIONAL WAVE TO DO THIS, 561 00:29:49,862 --> 00:29:53,379 THAT'S THE WAY THE DETECTION IS MADE. 562 00:29:53,379 --> 00:29:55,000 IT'S REALLY AS SIMPLE AS THAT. 563 00:29:55,000 --> 00:29:56,551 ♪♪ 564 00:29:56,551 --> 00:29:58,827 Narrator: IF RAI'S CALCULATIONS WERE RIGHT, 565 00:29:58,827 --> 00:30:02,137 HIS SYSTEM WOULD BE ABLE TO PICK UP MOVEMENTS IN THE MIRRORS 566 00:30:02,137 --> 00:30:05,517 OF JUST A FEW TRILLIONTHS OF A METER. 567 00:30:05,517 --> 00:30:08,241 I HEARD ABOUT THE IDEA. I DID SOME NUMBERS 568 00:30:08,241 --> 00:30:11,000 AND IT WAS OBVIOUS THAT RAI HAD GONE CRAZY OR SOMETHING. 569 00:30:11,000 --> 00:30:13,241 I JUST COULDN'T BELIEVE THAT HE COULD REALLY -- 570 00:30:13,241 --> 00:30:15,379 ANYONE COULD REALLY PULL THIS OFF. 571 00:30:15,379 --> 00:30:17,827 AND THEN I SPENT THE REST OF MY CAREER EATING CROW 572 00:30:17,827 --> 00:30:19,655 AND TRYING TO HELP HIM PULL IT OFF. 573 00:30:19,655 --> 00:30:24,206 ♪♪ 574 00:30:24,206 --> 00:30:26,862 Narrator: WHEN KIP THORNE, A THEORETICAL PHYSICIST 575 00:30:26,862 --> 00:30:28,655 AND CLOSE FRIEND OF STEPHEN HAWKING, 576 00:30:28,655 --> 00:30:30,965 JOINED THE PROJECT, 577 00:30:30,965 --> 00:30:33,551 HIS JOB WAS TO WORK OUT WHETHER 578 00:30:33,551 --> 00:30:36,206 THERE WERE ANY EVENTS IN THE UNIVERSE 579 00:30:36,206 --> 00:30:39,103 POWERFUL ENOUGH TO PRODUCE GRAVITATIONAL WAVES 580 00:30:39,103 --> 00:30:41,103 THAT RAI'S SYSTEM COULD DETECT. 581 00:30:41,103 --> 00:30:44,241 ♪♪ 582 00:30:44,241 --> 00:30:47,413 AS A THEORIST, I HAD THE BEST HANDLE ANYONE HAD. 583 00:30:47,413 --> 00:30:49,896 IT WAS NOT A GREAT HANDLE, BUT THE BEST HANDLE ANYONE HAD 584 00:30:49,896 --> 00:30:51,655 ON THE STRENGTHS OF THE SOURCES. 585 00:30:51,655 --> 00:30:55,862 ♪♪ 586 00:30:55,862 --> 00:30:58,310 Narrator: WHAT KIP NEEDED WAS A SOURCE 587 00:30:58,310 --> 00:31:00,758 OF GRAVITATIONAL ENERGY SO STRONG, 588 00:31:00,758 --> 00:31:05,655 IT WOULD SHAKE THE FABRIC OF THE ENTIRE UNIVERSE. 589 00:31:05,655 --> 00:31:07,655 THE SORT OF ENERGY THAT WOULD BE RELEASED 590 00:31:07,655 --> 00:31:11,620 IF TWO BLACK HOLES COLLIDED. 591 00:31:11,620 --> 00:31:14,862 YOU BEGAN WITH TWO MASSIVE STARS. 592 00:31:14,862 --> 00:31:16,620 THIS ONE COLLAPSED, FORMED A BLACK HOLE; 593 00:31:16,620 --> 00:31:20,379 AND THEN, LATER, THAT ONE COLLAPSED, FORMED A BLACK HOLE. 594 00:31:20,379 --> 00:31:24,275 AND THEN, CREATE A BINARY GOING AROUND EACH OTHER. 595 00:31:24,275 --> 00:31:26,827 THAT BINARY EMITS GRAVITATIONAL WAVES, 596 00:31:26,827 --> 00:31:29,172 SPIRALS TOGETHER CLOSER AND CLOSER 597 00:31:29,172 --> 00:31:32,724 AND THE BLACK HOLES COLLIDE. 598 00:31:32,724 --> 00:31:35,241 BUT WE'D NEVER SEEN PAIRS OF BLACK HOLES. 599 00:31:35,241 --> 00:31:37,448 WE COULDN'T SEE PAIRS OF BLACK HOLES 600 00:31:37,448 --> 00:31:40,379 BECAUSE BLACK HOLES DON'T EMIT ANY ELECTROMAGNETIC WAVES. 601 00:31:40,379 --> 00:31:41,413 AS THEY GO AROUND EACH OTHER, 602 00:31:41,413 --> 00:31:43,965 THEY ONLY PRODUCE GRAVITATIONAL WAVES, 603 00:31:43,965 --> 00:31:47,034 SO THE ONLY WAY WE WOULD EVER SEE THEM WAS WITH OUR DETECTORS. 604 00:31:47,034 --> 00:31:49,586 ♪♪ 605 00:31:49,586 --> 00:31:51,931 Narrator: TO TRY TO DETECT THE GRAVITATIONAL SIGNALS 606 00:31:51,931 --> 00:31:54,034 FROM COLLIDING BLACK HOLES, 607 00:31:54,034 --> 00:31:56,620 KIP THORNE AND RAI WEISS EMBARKED ON ONE 608 00:31:56,620 --> 00:32:00,034 OF THE MOST EXPENSIVE SCIENTIFIC VENTURES EVER ATTEMPTED. 609 00:32:00,034 --> 00:32:01,620 ♪♪ 610 00:32:01,620 --> 00:32:03,103 AFTER YEARS OF PLANNING, 611 00:32:03,103 --> 00:32:05,931 CONSTRUCTION STARTED IN LIVINGSTON, LOUISIANA, 612 00:32:05,931 --> 00:32:07,586 IN 1994. 613 00:32:07,586 --> 00:32:08,896 ♪♪ 614 00:32:08,896 --> 00:32:11,689 THE LASERS WOULD BE FIRED UP THESE ARMS, 615 00:32:11,689 --> 00:32:13,965 EACH 4 KILOMETERS LONG, 616 00:32:13,965 --> 00:32:15,758 BEFORE REFLECTING OFF THE MIRRORS 617 00:32:15,758 --> 00:32:18,413 AND RETURNING TO SENSORS SO FINELY TUNED, 618 00:32:18,413 --> 00:32:20,344 THEY COULD, IN THEORY, 619 00:32:20,344 --> 00:32:22,620 DETECT A SHORTENING OF THE ARMS CAUSED 620 00:32:22,620 --> 00:32:24,517 BY GRAVITATIONAL WAVES 621 00:32:24,517 --> 00:32:28,379 OF JUST A MILLION-MILLION- MILLIONTH OF A METER. 622 00:32:28,379 --> 00:32:29,827 ♪♪ 623 00:32:29,827 --> 00:32:32,862 3,000 MILES AWAY, IN HANFORD, WASHINGTON, 624 00:32:32,862 --> 00:32:35,172 AN IDENTICAL FACILITY WAS BUILT. 625 00:32:35,172 --> 00:32:37,206 ♪♪ 626 00:32:37,206 --> 00:32:39,482 FOR ANY DETECTION TO BE CONFIRMED, 627 00:32:39,482 --> 00:32:40,827 IT WOULD HAVE TO BE PICKED UP 628 00:32:40,827 --> 00:32:43,517 BY BOTH DETECTORS AT THE SAME TIME. 629 00:32:43,517 --> 00:32:46,103 ♪♪ 630 00:32:46,103 --> 00:32:50,034 THE INSTRUMENTS WERE ACTIVATED IN 2002. 631 00:32:50,034 --> 00:32:53,172 FOR EIGHT YEARS, THEY LISTENED TO THE UNIVERSE. 632 00:32:53,172 --> 00:32:57,172 BY 2010, THEY HAD HEARD ABSOLUTELY NOTHING. 633 00:32:57,172 --> 00:33:02,344 ♪♪ 634 00:33:02,344 --> 00:33:05,758 FOR THE LIGO TEAM, THE PRESSURE WAS MOUNTING. 635 00:33:05,758 --> 00:33:07,413 ♪♪ 636 00:33:07,413 --> 00:33:10,137 Thorne: WE HAD CONVINCED THE NSF AND CONGRESS 637 00:33:10,137 --> 00:33:12,034 THAT THEY SHOULD SPEND $1 BILLION ON THIS, 638 00:33:12,034 --> 00:33:14,137 AND WE HAD NOTHING TO SHOW FOR IT. 639 00:33:14,137 --> 00:33:16,000 ♪♪ 640 00:33:16,000 --> 00:33:17,896 Narrator: DOUBLING DOWN, THEY SHUT THE PROJECT 641 00:33:17,896 --> 00:33:19,793 FOR ANOTHER FIVE YEARS, 642 00:33:19,793 --> 00:33:23,620 TO INSTALL AN EVEN MORE PRECISE SET OF DETECTORS. 643 00:33:23,620 --> 00:33:25,793 ♪♪ 644 00:33:25,793 --> 00:33:28,034 IT WAS A HIGH-STAKES GAMBLE. 645 00:33:28,034 --> 00:33:35,551 ♪♪ 646 00:33:35,551 --> 00:33:38,310 ♪♪ 647 00:33:38,310 --> 00:33:41,137 Narrator: IN SEPTEMBER 2015, 648 00:33:41,137 --> 00:33:44,758 ALMOST EXACTLY 100 YEARS AFTER EINSTEIN PUBLISHED 649 00:33:44,758 --> 00:33:46,931 HIS THEORY OF GENERAL RELATIVITY, 650 00:33:46,931 --> 00:33:50,896 RAI WEISS' DETECTORS WERE REACTIVATED. 651 00:33:50,896 --> 00:33:53,448 JUST TWO DAYS LATER, 652 00:33:53,448 --> 00:33:57,241 BOTH SITES RECORDED AN UNUSUAL SIGNAL. 653 00:33:57,241 --> 00:34:00,103 LADIES AND GENTLEMEN, 654 00:34:00,103 --> 00:34:04,448 WE HAVE DETECTED GRAVITATIONAL WAVES. 655 00:34:04,448 --> 00:34:05,793 WE DID IT. 656 00:34:05,793 --> 00:34:08,413 [ CHEERS AND APPLAUSE ] 657 00:34:08,413 --> 00:34:12,103 Narrator: AFTER WORKING ON THE PROBLEM FOR ALMOST 50 YEARS, 658 00:34:12,103 --> 00:34:16,793 IT WAS A MASSIVE VINDICATION FOR RAI AND HIS FRIEND KIP. 659 00:34:16,793 --> 00:34:22,724 I WANT TO FIRST REMIND YOU OF EINSTEIN'S 1915 BIG DISCOVERY 660 00:34:22,724 --> 00:34:26,586 WAS REALLY THE FORMULATION OF THESE FIELD EQUATIONS. 661 00:34:26,586 --> 00:34:29,344 HE APPLIED THESE FIELD EQUATIONS 662 00:34:29,344 --> 00:34:31,758 TO THE IDEA OF GRAVITATIONAL WAVES. 663 00:34:31,758 --> 00:34:35,413 ♪♪ 664 00:34:35,413 --> 00:34:37,827 Weiss: ALMOST THE FIRST DAY OF THE REAL RUN, 665 00:34:37,827 --> 00:34:41,103 WE SAW WHAT IS IN FRONT OF YOU ON THE SCREEN HERE. 666 00:34:41,103 --> 00:34:42,551 AND LET ME PLAY IT FOR YOU. 667 00:34:42,551 --> 00:34:45,862 [ THUMPING ] 668 00:34:45,862 --> 00:34:47,517 THAT ISN'T MUCH. IT'S A LITTLE BLIP. 669 00:34:47,517 --> 00:34:49,137 THAT'S ALL YOU HEARD. 670 00:34:49,137 --> 00:34:50,862 BUT LET ME CHANGE -- AND THIS IS THE TRICK. 671 00:34:50,862 --> 00:34:52,448 WE MADE IT SO THAT YOU COULD HEAR IT BETTER 672 00:34:52,448 --> 00:34:54,758 BY CHANGING THE FREQUENCY OF EVERYTHING. 673 00:34:54,758 --> 00:35:02,275 [ BLIPS ] 674 00:35:02,275 --> 00:35:05,137 AND THAT CHIRP IS THE CHARACTERISTIC 675 00:35:05,137 --> 00:35:07,310 OF THIS PARTICULAR SOURCE. 676 00:35:07,310 --> 00:35:11,068 AND THAT WAS SOMETHING WHICH WAS QUITE ASTOUNDING TO US. 677 00:35:11,068 --> 00:35:14,172 [ BLIPS ] 678 00:35:14,172 --> 00:35:17,379 ♪♪ 679 00:35:17,379 --> 00:35:21,551 Narrator: LONG, LONG AGO, IN A GALAXY FAR, FAR AWAY, 680 00:35:21,551 --> 00:35:23,517 A PAIR OF BLACK HOLES, 681 00:35:23,517 --> 00:35:26,517 EACH AROUND 30 TIMES THE MASS OF THE SUN, 682 00:35:26,517 --> 00:35:30,965 CIRCLED EACH OTHER, MOVING FASTER AND CLOSER. 683 00:35:30,965 --> 00:35:34,758 ♪♪ 684 00:35:34,758 --> 00:35:38,655 Thorne: THE POINT WHEN WE FIRST SEE THE GRAVITATIONAL WAVES, 685 00:35:38,655 --> 00:35:41,413 THEY'RE MAYBE 1,000 KILOMETERS APART, 686 00:35:41,413 --> 00:35:44,482 EACH ONE ROUGHLY 100 KILOMETERS IN SIZE. 687 00:35:44,482 --> 00:35:46,068 THEY'RE GOING AROUND AND AROUND, 688 00:35:46,068 --> 00:35:52,241 CREATING STRONGER AND STRONGER WARPING OF SPACE AND TIME. 689 00:35:52,241 --> 00:35:54,896 AS THEY NEAR EACH OTHER, 690 00:35:54,896 --> 00:35:58,896 THEY WARP SPACE AND TIME IN A WILD WAY, 691 00:35:58,896 --> 00:36:03,241 VERY MUCH LIKE A STORM AT SEA. 692 00:36:03,241 --> 00:36:07,310 Narrator: AND THEN, THE BLACK HOLES COALESCE. 693 00:36:07,310 --> 00:36:10,206 ♪♪ 694 00:36:10,206 --> 00:36:13,724 IN THAT INSTANT, THREE TIMES THE MASS OF THE SUN 695 00:36:13,724 --> 00:36:16,310 IS CONVERTED INTO PURE ENERGY. 696 00:36:16,310 --> 00:36:18,896 ♪♪ 697 00:36:18,896 --> 00:36:22,310 BUT NONE OF THAT ENERGY IS EMITTED AS LIGHT. 698 00:36:22,310 --> 00:36:26,758 IT IS ALL RELEASED AS GRAVITATIONAL WAVES. 699 00:36:26,758 --> 00:36:29,448 SO THE HUGE AMOUNT OF ENERGY 700 00:36:29,448 --> 00:36:33,896 TURNS OUT TO BE 50 TIMES HIGHER THAN THE TOTAL POWER OUTPUT 701 00:36:33,896 --> 00:36:36,310 OF ALL THE STARS IN THE UNIVERSE PUT TOGETHER. 702 00:36:36,310 --> 00:36:39,000 ♪♪ 703 00:36:39,000 --> 00:36:43,758 BY FAR, THE LARGEST EXPLOSION, IN TERMS OF POWER OUTPUT, 704 00:36:43,758 --> 00:36:45,827 EXCEPT THE BIG BANG, 705 00:36:45,827 --> 00:36:48,310 THAT WE EVER HAD ANY EVIDENCE OF. 706 00:36:48,310 --> 00:36:53,517 ♪♪ 707 00:36:53,517 --> 00:36:56,965 Narrator: AS THEY TRAVEL THROUGH SPACE AT THE SPEED OF LIGHT, 708 00:36:56,965 --> 00:37:01,689 THE WAVES DISSIPATE, GETTING SMALLER AND SMALLER, 709 00:37:01,689 --> 00:37:06,655 UNTIL, 1.3 BILLION YEARS LATER, 710 00:37:06,655 --> 00:37:09,379 THEY PASSED THROUGH RAI'S DETECTORS. 711 00:37:09,379 --> 00:37:14,413 [ BLIPS ] 712 00:37:14,413 --> 00:37:16,448 I WISH I COULD HAVE TOLD EINSTEIN DIRECTLY 713 00:37:16,448 --> 00:37:19,241 THAT WE HAD SEEN A BLACK HOLE DOING THIS. 714 00:37:19,241 --> 00:37:21,655 THAT WOULD HAVE BEEN JUST A WONDERFUL EXPERIENCE, 715 00:37:21,655 --> 00:37:23,724 TO SEE THE EXPRESSION ON HIS FACE 716 00:37:23,724 --> 00:37:25,551 AFTER WE'D TOLD HIM THAT. 717 00:37:25,551 --> 00:37:29,068 [ BLIPS ] 718 00:37:29,068 --> 00:37:31,448 Narrator: THE DISCOVERY OF GRAVITATIONAL WAVES 719 00:37:31,448 --> 00:37:33,000 IS THE ULTIMATE TRIUMPH 720 00:37:33,000 --> 00:37:37,758 OF EINSTEIN'S THEORY OF RELATIVITY, 721 00:37:37,758 --> 00:37:40,655 A THEORY THAT HAS BEEN REPEATEDLY TESTED 722 00:37:40,655 --> 00:37:42,586 AND PROVEN TO BE CORRECT. 723 00:37:42,586 --> 00:37:44,137 ♪♪ 724 00:37:44,137 --> 00:37:46,965 EINSTEIN DIED IN 1955. 725 00:37:46,965 --> 00:37:48,862 IN JUST HALF A CENTURY, 726 00:37:48,862 --> 00:37:53,137 HE HAD REIMAGINED THE ENTIRE UNIVERSE. 727 00:37:53,137 --> 00:37:56,827 WELL, ALBERT EINSTEIN ENTERS THE WORLD WHEN IT'S ONE WAY 728 00:37:56,827 --> 00:37:58,758 AND, BY THE TIME HE LEAVES THE WORLD, 729 00:37:58,758 --> 00:38:00,827 IT'S COMPLETELY DIFFERENT. 730 00:38:00,827 --> 00:38:03,827 WE NOW LIVE IN A WORLD WHERE WE UNDERSTAND 731 00:38:03,827 --> 00:38:05,482 THE UNIVERSE HAD A BEGINNING 732 00:38:05,482 --> 00:38:07,517 AND WE CAN TELL HOW LONG AGO IT WAS. 733 00:38:07,517 --> 00:38:11,206 THOSE ARE STUNNING ACHIEVEMENTS AND STUNNING SHIFTS, 734 00:38:11,206 --> 00:38:15,448 BOTH IN OUR SCIENTIFIC AND OUR CULTURAL PERSPECTIVE. 735 00:38:15,448 --> 00:38:18,275 Green: HE WAS A FIGURE THAT IS RARE, YOU KNOW, 736 00:38:18,275 --> 00:38:21,413 ONCE IN A HUNDRED YEARS, MAYBE ONCE IN 500 YEARS. 737 00:38:21,413 --> 00:38:29,896 ♪♪ 738 00:38:29,896 --> 00:38:32,103 ♪♪ 739 00:38:32,103 --> 00:38:35,379 Narrator: STEPHEN HAWKING'S GREATEST CONTRIBUTION TO PHYSICS 740 00:38:35,379 --> 00:38:39,758 WAS HIS DISCOVERY THAT BLACK HOLES COULD EVAPORATE. 741 00:38:39,758 --> 00:38:43,206 IF HIS THEORY OF HAWKING RADIATION WAS CORRECT, 742 00:38:43,206 --> 00:38:45,344 IT WOULD HAVE PROFOUND IMPLICATIONS 743 00:38:45,344 --> 00:38:48,379 FOR THE WAY WE UNDERSTAND THE ENTIRE UNIVERSE. 744 00:38:48,379 --> 00:38:51,379 ♪♪ 745 00:38:51,379 --> 00:38:53,103 IN HAIFA, ISRAEL, 746 00:38:53,103 --> 00:38:56,000 JEFF STEINHAUER HAS SPENT A DECADE SEARCHING 747 00:38:56,000 --> 00:38:59,551 FOR EVIDENCE OF HAWKING RADIATION, 748 00:38:59,551 --> 00:39:04,034 USING ARTIFICIAL BLACK HOLES THAT HE MAKES OUT OF SOUND. 749 00:39:04,034 --> 00:39:06,137 ♪♪ 750 00:39:06,137 --> 00:39:07,413 Steinhauer: SO, HERE WE GO. 751 00:39:07,413 --> 00:39:10,448 ALL THE EQUIPMENT THAT YOU SEE 752 00:39:10,448 --> 00:39:13,620 IS FOR THE SAKE OF THE SMALL POINT RIGHT IN THERE 753 00:39:13,620 --> 00:39:17,724 WHERE THE ARTIFICIAL BLACK HOLE IS. 754 00:39:17,724 --> 00:39:20,413 WE START OUT WITH THESE VERY COLD ATOMS 755 00:39:20,413 --> 00:39:21,827 IN THIS TUBE-LIKE VOLUME 756 00:39:21,827 --> 00:39:25,413 AND IT'S ONLY 0.1 MILLIMETERS LONG. 757 00:39:25,413 --> 00:39:26,896 WE THEN APPLY 758 00:39:26,896 --> 00:39:29,724 A BLUE LASER BEAM WHICH CAUSES SOME 759 00:39:29,724 --> 00:39:32,517 OF THE ATOMS TO BE ACCELERATED TO SUPERSONIC SPEEDS. 760 00:39:32,517 --> 00:39:33,931 SO, IN THIS REGION, 761 00:39:33,931 --> 00:39:36,586 THEY'RE FLOWING SLOWER THAN THE SPEED OF SOUND 762 00:39:36,586 --> 00:39:39,689 AND, HERE, THEY'RE FLOWING FASTER THAN THE SPEED OF SOUND. 763 00:39:39,689 --> 00:39:42,793 SO, HERE, IN THE SUPERSONIC REGION, 764 00:39:42,793 --> 00:39:46,068 A SOUND WAVE TRYING TO MOVE AGAINST THE FLOW 765 00:39:46,068 --> 00:39:47,344 WILL ACTUALLY FALL BACK. 766 00:39:47,344 --> 00:39:50,517 IT CAN'T GO FORWARD AGAINST THE VERY FAST FLOW. 767 00:39:50,517 --> 00:39:52,344 ♪♪ 768 00:39:52,344 --> 00:39:54,689 Narrator: IN HIS ARTIFICIAL BLACK HOLE, 769 00:39:54,689 --> 00:39:58,482 JEFF HAS CREATED AN EVENT HORIZON. 770 00:39:58,482 --> 00:40:00,793 ONCE THE SOUND WAVE IS OVER THAT LINE, 771 00:40:00,793 --> 00:40:02,793 IT CANNOT ESCAPE, 772 00:40:02,793 --> 00:40:06,827 JUST AS LIGHT CANNOT ESCAPE A REAL BLACK HOLE. 773 00:40:06,827 --> 00:40:10,655 AND, WHEN JEFF TAKES PHOTOS OF HIS SONIC EVENT HORIZON, 774 00:40:10,655 --> 00:40:13,965 HE SEES SOMETHING VERY STRANGE -- 775 00:40:13,965 --> 00:40:17,965 THE TELLTALE SIGNS OF HAWKING RADIATION. 776 00:40:17,965 --> 00:40:20,000 Steinhauer: YOU SEE THIS BAND? 777 00:40:20,000 --> 00:40:23,103 THIS BAND IS AN OBSERVATION OF SOUND WAVES BEING EMITTED 778 00:40:23,103 --> 00:40:25,103 FROM THE HORIZON OF THE BLACK HOLE. 779 00:40:25,103 --> 00:40:26,896 ♪♪ 780 00:40:26,896 --> 00:40:28,862 THIS EXPERIMENT IS THE FIRST TIME 781 00:40:28,862 --> 00:40:30,896 THAT HAWKING RADIATION'S BEEN OBSERVED. 782 00:40:30,896 --> 00:40:32,793 ♪♪ 783 00:40:32,793 --> 00:40:35,655 Narrator: IT IS AN AMAZING DISCOVERY, 784 00:40:35,655 --> 00:40:38,517 WHICH SUGGESTS THAT HAWKING RADIATION 785 00:40:38,517 --> 00:40:43,000 MAY BE A FUNDAMENTAL FEATURE OF BLACK HOLES. 786 00:40:43,000 --> 00:40:44,620 IF THAT'S TRUE, 787 00:40:44,620 --> 00:40:46,965 IT MEANS THAT, GIVEN ENOUGH TIME, 788 00:40:46,965 --> 00:40:50,103 ALL BLACK HOLES WILL EVAPORATE. 789 00:40:50,103 --> 00:40:53,172 AND THAT PROSPECT HAS TROUBLING IMPLICATIONS 790 00:40:53,172 --> 00:40:54,931 FOR THE REST OF PHYSICS. 791 00:40:54,931 --> 00:40:56,793 [ FLAMES CRACKLING ] 792 00:40:56,793 --> 00:41:02,034 ♪♪ 793 00:41:02,034 --> 00:41:07,758 ♪♪ 794 00:41:07,758 --> 00:41:10,344 A CENTRAL PRINCIPLE OF ALL PHYSICS -- 795 00:41:10,344 --> 00:41:13,655 IN FACT, IT'S WRITTEN INTO THE LAWS OF QUANTUM THEORY -- 796 00:41:13,655 --> 00:41:16,655 IS THAT INFORMATION CANNOT BE DESTROYED. 797 00:41:16,655 --> 00:41:18,655 CONSIDER THIS NEWSPAPER. 798 00:41:18,655 --> 00:41:21,310 IT HAS INFORMATION ON EVERY PAGE 799 00:41:21,310 --> 00:41:23,551 AND, IF I WERE TO THROW IT ON THIS FIRE, 800 00:41:23,551 --> 00:41:26,620 IT'S QUICKLY CONSUMED BY THE FLAMES 801 00:41:26,620 --> 00:41:30,034 AND IT LOOKS LIKE THE INFORMATION IS DESTROYED. 802 00:41:30,034 --> 00:41:32,517 BUT IF I WERE ABLE TO TAKE ALL THE ASHES, 803 00:41:32,517 --> 00:41:35,137 COLLECT ALL THE SMOKE AND ALL THE HEAT, 804 00:41:35,137 --> 00:41:39,413 AND ANALYZE AND RECONSTRUCT THE PATHS OF ALL THE PARTICLES, 805 00:41:39,413 --> 00:41:44,689 I SHOULD BE ABLE TO RECONSTRUCT WHAT'S ON EVERY PAGE. 806 00:41:44,689 --> 00:41:48,000 AND THIS IS BECAUSE THE LAWS OF PHYSICS ALLOW US 807 00:41:48,000 --> 00:41:50,000 TO TELL THE ENTIRE FUTURE 808 00:41:50,000 --> 00:41:53,758 AND THE ENTIRE PAST OF ANY SYSTEM. 809 00:41:53,758 --> 00:41:56,620 NO ONE'S SAYING IT'S EASY, BUT IT IS POSSIBLE, 810 00:41:56,620 --> 00:42:00,172 AS LONG AS YOU HAVE ALL THE INFORMATION. 811 00:42:00,172 --> 00:42:02,827 WE CALL THIS DETERMINISM. 812 00:42:02,827 --> 00:42:05,034 [ FLAMES CRACKLING ] 813 00:42:05,034 --> 00:42:08,448 Narrator: SCIENTISTS BELIEVE THAT THE PRINCIPLE OF DETERMINISM 814 00:42:08,448 --> 00:42:10,724 APPLIES TO ALL SYSTEMS, 815 00:42:10,724 --> 00:42:13,620 NO MATTER HOW BIG OR HOW COMPLEX. 816 00:42:13,620 --> 00:42:18,517 IT SHOULD EVEN APPLY TO THE ENTIRE UNIVERSE. 817 00:42:18,517 --> 00:42:21,551 SO, IF I WERE TO SOMEHOW KNOW THE POSITION AND STATE 818 00:42:21,551 --> 00:42:23,517 OF EVERY PARTICLE IN THE UNIVERSE, 819 00:42:23,517 --> 00:42:25,620 I COULD APPLY THE LAWS OF PHYSICS 820 00:42:25,620 --> 00:42:28,241 AND KNOW THE ENTIRE FUTURE OF THE UNIVERSE 821 00:42:28,241 --> 00:42:31,793 AND THE ENTIRE PAST OF THE UNIVERSE. 822 00:42:31,793 --> 00:42:33,931 BUT THERE'S A CATCH, BECAUSE IF, 823 00:42:33,931 --> 00:42:36,517 AS HAWKING PREDICTED, BLACK HOLES COULD EVAPORATE 824 00:42:36,517 --> 00:42:38,172 IN SUCH A WAY THAT THEY LEAVE BEHIND 825 00:42:38,172 --> 00:42:40,724 NO TRACE OF THE MATERIAL THAT WAS INSIDE, 826 00:42:40,724 --> 00:42:42,620 THEN INFORMATION COULD BE LOST 827 00:42:42,620 --> 00:42:45,758 AND, EVEN IF ONLY A SMALL AMOUNT OF INFORMATION IS LOST, 828 00:42:45,758 --> 00:42:47,172 THEN EVERYTHING IS LOST. 829 00:42:47,172 --> 00:42:48,862 YOU CAN'T RECONSTRUCT THE PAST 830 00:42:48,862 --> 00:42:50,793 AND YOU CAN'T PREDICT THE FUTURE. 831 00:42:50,793 --> 00:42:52,379 IT SEEMS TRIVIAL, 832 00:42:52,379 --> 00:42:54,931 BUT, ACTUALLY, IT WAS A MASSIVE PROBLEM 833 00:42:54,931 --> 00:42:57,758 THAT SHOOK THE VERY FOUNDATIONS OF PHYSICS 834 00:42:57,758 --> 00:43:01,413 AND THIS BECAME KNOWN AS THE INFORMATION PARADOX. 835 00:43:01,413 --> 00:43:05,344 ♪♪ 836 00:43:05,344 --> 00:43:06,931 Hawking: IF DETERMINISM, 837 00:43:06,931 --> 00:43:09,413 THE PREDICTABILITY OF THE UNIVERSE, 838 00:43:09,413 --> 00:43:12,482 BREAKS DOWN WITH BLACK HOLES, 839 00:43:12,482 --> 00:43:16,172 IT COULD BREAK DOWN IN OTHER SITUATIONS. 840 00:43:16,172 --> 00:43:21,103 EVEN WORSE, IF DETERMINISM BREAKS DOWN, 841 00:43:21,103 --> 00:43:24,413 WE CAN'T BE SURE OF OUR PAST HISTORY, EITHER. 842 00:43:24,413 --> 00:43:26,517 ♪♪ 843 00:43:26,517 --> 00:43:28,517 THE HISTORY BOOKS AND OUR MEMORIES 844 00:43:28,517 --> 00:43:31,413 COULD JUST BE ILLUSIONS. 845 00:43:31,413 --> 00:43:36,517 IT IS THE PAST THAT TELLS US WHO WE ARE. 846 00:43:36,517 --> 00:43:40,172 WITHOUT IT, WE LOSE OUR IDENTITY. 847 00:43:40,172 --> 00:43:46,137 ♪♪ 848 00:43:46,137 --> 00:43:48,000 Narrator: THE INFORMATION PARADOX 849 00:43:48,000 --> 00:43:50,931 HAS TROUBLED PHYSICISTS FOR DECADES. 850 00:43:50,931 --> 00:43:52,482 IF HAWKING WAS RIGHT 851 00:43:52,482 --> 00:43:56,310 AND BLACK HOLES DID DESTROY THE INFORMATION THEY CONTAINED, 852 00:43:56,310 --> 00:43:58,068 THEN THEY WOULD ALSO DESTROY 853 00:43:58,068 --> 00:44:01,931 ALMOST EVERYTHING WE KNOW ABOUT MODERN PHYSICS. 854 00:44:01,931 --> 00:44:05,068 IT CREATED THIS BIG RIFT BETWEEN THOSE 855 00:44:05,068 --> 00:44:06,758 WHO WERE ADHERENTS TO QUANTUM THINKING 856 00:44:06,758 --> 00:44:09,172 AND THOSE WHO WERE ADHERENTS TO RELATIVITY. 857 00:44:09,172 --> 00:44:11,689 THE QUANTUM PEOPLE SAYING, "THE INFORMATION MUST GET OUT. 858 00:44:11,689 --> 00:44:13,931 WE DON'T KNOW HOW, WE DON'T SEE HOW, BUT IT MUST." 859 00:44:13,931 --> 00:44:16,206 AND THE RELATIVISTS SAYING, "YOU KNOW, MAYBE, 860 00:44:16,206 --> 00:44:18,482 MAYBE THE INFORMATION'S JUST LOST." 861 00:44:18,482 --> 00:44:20,965 I'M INCLINED TO SUSPECT THAT INFORMATION 862 00:44:20,965 --> 00:44:23,137 IS TRULY LOST DOWN BLACK HOLES, 863 00:44:23,137 --> 00:44:25,862 BUT MINE IS THE MINORITY POINT OF VIEW. 864 00:44:25,862 --> 00:44:28,137 WHO CARES IF BLACK HOLES EVAPORATE 865 00:44:28,137 --> 00:44:32,827 AND SWALLOW LITTLE BITS OF INFORMATION AS THEY GO? 866 00:44:32,827 --> 00:44:37,172 BUT, IN THE 40-PLUS YEARS SINCE THEN, 867 00:44:37,172 --> 00:44:40,034 IT'S KIND OF BEEN LIKE A SNOWBALL, 868 00:44:40,034 --> 00:44:46,413 THE IMPORTANCE OF THIS PROBLEM, AND HAS GROWN AND GROWN. 869 00:44:46,413 --> 00:44:55,586 ♪♪ 870 00:44:55,586 --> 00:44:58,689 Narrator: THE INFORMATION PARADOX WAS A PROBLEM 871 00:44:58,689 --> 00:45:01,965 THAT STEPHEN HAWKING WORKED ON FOR OVER FOUR DECADES. 872 00:45:01,965 --> 00:45:04,275 ♪♪ 873 00:45:04,275 --> 00:45:08,689 AND, IN 2015, HE CAME UP WITH A MAJOR BREAKTHROUGH. 874 00:45:08,689 --> 00:45:10,655 ♪♪ 875 00:45:10,655 --> 00:45:14,965 Hawking: MANY SCIENTISTS FELT THAT INFORMATION SHOULD NOT BE LOST, 876 00:45:14,965 --> 00:45:17,448 BUT NO ONE COULD SUGGEST A MECHANISM 877 00:45:17,448 --> 00:45:20,827 BY WHICH IT COULD BE PRESERVED. 878 00:45:20,827 --> 00:45:24,413 THE ARGUMENTS WENT ON FOR YEARS. 879 00:45:24,413 --> 00:45:29,689 FINALLY, I FOUND WHAT I THINK IS THE ANSWER. 880 00:45:29,689 --> 00:45:32,000 I REALIZED THAT A BLACK HOLE 881 00:45:32,000 --> 00:45:35,172 CAN STORE THE INFORMATION IN WHAT IS CALLED 882 00:45:35,172 --> 00:45:37,482 SUPERTRANSLATIONS OF THE HORIZON. 883 00:45:37,482 --> 00:45:39,344 ♪♪ 884 00:45:39,344 --> 00:45:41,310 Narrator: HAWKING'S NEW IDEA 885 00:45:41,310 --> 00:45:46,862 WAS THAT, AS OBJECTS FALL INTO A BLACK HOLE, 886 00:45:46,862 --> 00:45:50,931 THEY DISTURB THE EVENT HORIZON, 887 00:45:50,931 --> 00:45:53,275 LEAVING BEHIND A PATTERN OF TURBULENCE, 888 00:45:53,275 --> 00:45:55,034 WHICH COULD PRESERVE THE INFORMATION 889 00:45:55,034 --> 00:45:57,724 ABOUT EVERYTHING THAT'S FALLEN INSIDE. 890 00:45:57,724 --> 00:45:59,620 ♪♪ 891 00:45:59,620 --> 00:46:02,827 Hawking: I'M NOW WORKING WITH MY COLLEAGUES 892 00:46:02,827 --> 00:46:06,758 MALCOLM PERRY AT CAMBRIDGE 893 00:46:06,758 --> 00:46:09,724 AND ANDREW STROMINGER AT HARVARD 894 00:46:09,724 --> 00:46:14,103 ON WHETHER THIS CAN RESOLVE THE PARADOX. 895 00:46:14,103 --> 00:46:16,448 Perry: IF INFORMATION IS STUCK ON THE HORIZON, 896 00:46:16,448 --> 00:46:19,689 IT HAS NOT FALLEN INTO THE BLACK HOLE. 897 00:46:19,689 --> 00:46:22,862 AND YOU CAN'T DIRECTLY OBSERVE IT FROM THE OUTSIDE, 898 00:46:22,862 --> 00:46:25,344 BUT WHAT WILL HAPPEN IS IT WILL INFLUENCE 899 00:46:25,344 --> 00:46:29,172 THE HAWKING RADIATION THAT COMES OUT OF THE BLACK HOLE 900 00:46:29,172 --> 00:46:32,137 AND THAT MAY BE ENOUGH TO HELP YOU RESOLVE 901 00:46:32,137 --> 00:46:33,862 THE INFORMATION PARADOX. 902 00:46:33,862 --> 00:46:37,586 ♪♪ 903 00:46:37,586 --> 00:46:43,551 Strominger: WHEN WE FIRST CAME UPON IT, WE WERE UP UNTIL LATE AT NIGHT. 904 00:46:43,551 --> 00:46:47,172 HE SAID HE HADN'T BEEN THIS EXCITED IN 40 YEARS. 905 00:46:47,172 --> 00:46:50,103 ♪♪ 906 00:46:50,103 --> 00:46:54,068 AND HE STARTED WORKING ON IT BASICALLY FULL-TIME. 907 00:46:54,068 --> 00:46:56,413 ♪♪ 908 00:46:56,413 --> 00:47:00,344 Narrator: TOGETHER, THE SCIENTISTS WROTE THREE PAPERS ON THE SUBJECT... 909 00:47:00,344 --> 00:47:02,862 ♪♪ 910 00:47:02,862 --> 00:47:06,517 ...EDGING CLOSER TO A SOLUTION TO THE INFORMATION PARADOX. 911 00:47:06,517 --> 00:47:10,862 ♪♪ 912 00:47:10,862 --> 00:47:13,620 IT WAS HAWKING'S LAST GREAT IDEA. 913 00:47:13,620 --> 00:47:18,965 ♪♪ 914 00:47:18,965 --> 00:47:23,586 SADLY, THIS IS THE LAST PAPER THAT STEPHEN WROTE. 915 00:47:23,586 --> 00:47:26,482 HE WAS FULL ENGAGED WITH IT RIGHT TILL THE VERY END. 916 00:47:26,482 --> 00:47:34,586 ♪♪ 917 00:47:34,586 --> 00:47:38,172 Narrator: HAWKING DIED IN MARCH 2018 918 00:47:38,172 --> 00:47:40,620 AT THE AGE OF 76, 919 00:47:40,620 --> 00:47:42,275 OVER HALF A CENTURY 920 00:47:42,275 --> 00:47:45,413 AFTER HE HAD BEEN GIVEN JUST TWO YEARS TO LIVE. 921 00:47:45,413 --> 00:47:49,275 ♪♪ 922 00:47:49,275 --> 00:47:52,965 Strominger: HE WAS KIND OF MAGICAL TO BE AROUND. 923 00:47:52,965 --> 00:47:55,931 WHEN I MISS HIM THE MOST IS WHEN WE FIGURE SOMETHING OUT, 924 00:47:55,931 --> 00:47:57,827 I'D LIKE TO TELL HIM. 925 00:47:57,827 --> 00:48:05,896 ♪♪ 926 00:48:05,896 --> 00:48:08,172 Narrator: SUCH WAS HIS CONTRIBUTION TO SCIENCE, 927 00:48:08,172 --> 00:48:12,482 HIS ASHES WERE INTERRED IN WESTMINSTER ABBEY, 928 00:48:12,482 --> 00:48:15,482 ALONGSIDE SIR ISAAC NEWTON AND CHARLES DARWIN... 929 00:48:15,482 --> 00:48:18,620 ♪♪ 930 00:48:18,620 --> 00:48:23,793 STEPHEN WAS ONE OF THE GREAT MINDS OF THE 20th CENTURY, 931 00:48:23,793 --> 00:48:27,000 IN TERMS OF HIS IMPACT ON OUR UNDERSTANDING 932 00:48:27,000 --> 00:48:31,379 OF THE LAWS THAT GOVERN THE UNIVERSE. 933 00:48:31,379 --> 00:48:33,413 I MISS STEPHEN GREATLY. 934 00:48:33,413 --> 00:48:36,482 IT WAS A TREMENDOUS LOSS FOR ME, PERSONALLY. 935 00:48:36,482 --> 00:48:39,379 ♪♪ 936 00:48:39,379 --> 00:48:41,965 Narrator: ...HIS GRAVESTONE ENGRAVED 937 00:48:41,965 --> 00:48:45,586 WITH THE EQUATION DESCRIBING HAWKING RADIATION. 938 00:48:45,586 --> 00:48:47,620 ♪♪ 939 00:48:47,620 --> 00:48:53,241 STEPHEN HAWKING'S LEGACY WILL CLEARLY BE A VITAL PART 940 00:48:53,241 --> 00:48:54,965 IN THE UNFOLDING STORY 941 00:48:54,965 --> 00:48:58,862 OF PUTTING GRAVITY AND QUANTUM MECHANICS TOGETHER. 942 00:48:58,862 --> 00:49:02,862 ♪♪ 943 00:49:02,862 --> 00:49:04,862 AND, AS WE GO FORWARD, EVERYTHING THAT WE DO, 944 00:49:04,862 --> 00:49:08,482 IN SOME SENSE, WILL GO RIGHT BACK TO STEPHEN HAWKING. 945 00:49:08,482 --> 00:49:11,448 [ CLOCK TICKING ] 946 00:49:11,448 --> 00:49:15,275 Narrator: TIME -- WE THINK OF IT AS REGULAR AS CLOCKWORK... 947 00:49:15,275 --> 00:49:18,310 ♪♪ 948 00:49:18,310 --> 00:49:21,413 ...TICKING OUT THE STEADY PROGRESS OF THE UNIVERSE. 949 00:49:21,413 --> 00:49:23,655 ♪♪ 950 00:49:23,655 --> 00:49:27,586 BUT TIME IS NOT CONSTANT. 951 00:49:27,586 --> 00:49:30,586 IT HOLDS THE KEY TO THE SECRETS OF THE UNIVERSE. 952 00:49:30,586 --> 00:49:33,206 ♪♪ 953 00:49:33,206 --> 00:49:36,551 AND THE TWO PEOPLE WHO HELPED US UNLOCK THOSE MYSTERIES 954 00:49:36,551 --> 00:49:40,034 ARE JOINED BY A COSMIC COINCIDENCE OF TIMING. 955 00:49:40,034 --> 00:49:46,103 ♪♪ 956 00:49:46,103 --> 00:49:48,931 ON MARCH 14, 1879, 957 00:49:48,931 --> 00:49:51,275 ALBERT EINSTEIN WAS BORN. 958 00:49:51,275 --> 00:49:52,655 ♪♪ 959 00:49:52,655 --> 00:49:56,068 Kaiser: EINSTEIN GAVE TO US ALL A SET OF TOOLS 960 00:49:56,068 --> 00:50:00,551 THAT LITERALLY HELP US ORGANIZE THE WORLD AROUND US TO THIS DAY. 961 00:50:00,551 --> 00:50:04,137 Narrator: AND, ON MARCH 14, 2018, 962 00:50:04,137 --> 00:50:06,275 STEPHEN HAWKING DIED. 963 00:50:06,275 --> 00:50:07,758 ♪♪ 964 00:50:07,758 --> 00:50:09,379 I THINK STEPHEN SHOULD BE REMEMBERED 965 00:50:09,379 --> 00:50:14,310 AS ONE OF THE MOST REMARKABLE PEOPLE OF THE 21st CENTURY. 966 00:50:14,310 --> 00:50:18,034 HE IS SOMEONE WHO, IN A THOUSAND YEARS FROM NOW, 967 00:50:18,034 --> 00:50:19,172 WILL BE REMEMBERED. 968 00:50:19,172 --> 00:50:21,103 HIS NAME WILL BE KNOWN. 969 00:50:21,103 --> 00:50:22,689 THAT'S NOT TRUE FOR MOST OF US. 970 00:50:22,689 --> 00:50:24,448 ♪♪ 971 00:50:24,448 --> 00:50:26,862 Narrator: BETWEEN THEM, THEY HAVE TRANSFORMED 972 00:50:26,862 --> 00:50:30,068 OUR UNDERSTANDING OF THE ENTIRE UNIVERSE. 973 00:50:30,068 --> 00:50:31,586 ♪♪ 974 00:50:31,586 --> 00:50:35,586 AS A WORKING PHYSICIST, I LOOK AT THESE TWO GIANTS 975 00:50:35,586 --> 00:50:38,724 AND I HAVE NOTHING BUT GRATITUDE 976 00:50:38,724 --> 00:50:41,620 THAT THEY REVEALED THE WORLD TO BE SO MUCH MORE 977 00:50:41,620 --> 00:50:43,551 THAN IT WOULD HAVE BEEN. 978 00:50:43,551 --> 00:50:47,034 AND, WITHOUT THEM, WHO KNOWS IF WE WOULD'VE GOTTEN 979 00:50:47,034 --> 00:50:49,551 TO THIS WONDROUS STAGE IN OUR UNDERSTANDING. 980 00:50:49,551 --> 00:50:53,034 ♪♪ 981 00:50:53,034 --> 00:50:55,275 Hawking: I HAVE A REAL FEELING OF ACHIEVEMENT 982 00:50:55,275 --> 00:50:58,827 THAT I HAVE MADE A MODEST, BUT SIGNIFICANT, 983 00:50:58,827 --> 00:51:01,586 CONTRIBUTION TO HUMAN KNOWLEDGE 984 00:51:01,586 --> 00:51:03,379 DESPITE MY CONDITION. 985 00:51:03,379 --> 00:51:10,620 ♪♪ 986 00:51:10,620 --> 00:51:20,620 ♪♪ 987 00:51:20,620 --> 00:51:30,620 ♪♪ 988 00:51:30,620 --> 00:51:35,517 ♪♪