1 00:00:03,567 --> 00:00:08,367 Narrator: WE LIVE ON A VOLATILE PLANET IN A VIOLENT UNIVERSE... 2 00:00:08,367 --> 00:00:10,033 THE UNIVERSE CONSTANTLY WANTS TO KILL US. 3 00:00:10,033 --> 00:00:12,900 Narrator: ...WHERE PLANETS COLLIDE. 4 00:00:12,900 --> 00:00:15,367 THE ENTIRE SURFACE OF THE EARTH IS LIQUEFIED 5 00:00:15,367 --> 00:00:17,600 THAT WAS LITERALLY A VISION OF HELL. 6 00:00:19,133 --> 00:00:23,167 Narrator: BLACK HOLES BLAST OUT INVISIBLE DEATH RAYS. 7 00:00:23,167 --> 00:00:26,133 IT WOULD BE APOCALYPTIC BEYOND APOCALYPTIC. 8 00:00:26,133 --> 00:00:29,467 Narrator: ASTEROIDS STRIKE WITHOUT WARNING. 9 00:00:29,467 --> 00:00:31,267 IT IS A REAL POSSIBILITY 10 00:00:31,267 --> 00:00:33,033 THAT IT COULD HAPPEN IN THE NEXT 10 MINUTES. 11 00:00:33,033 --> 00:00:38,033 Narrator: THESE COSMIC KILLERS HAVE STRUCK TIME AND TIME AGAIN, 12 00:00:38,033 --> 00:00:40,133 WIPING OUT ENTIRE SPECIES, 13 00:00:40,133 --> 00:00:43,667 AND PUSHING LIFE ON EARTH TO THE EDGE OF OBLIVION. 14 00:00:43,667 --> 00:00:45,833 IT'S HAPPENED BEFORE. IT'S GONNA HAPPEN AGAIN. 15 00:00:45,833 --> 00:00:48,500 Narrator: AND OUR SPECIES COULD BE NEXT. 16 00:00:48,500 --> 00:00:50,700 Krauss: THERE WILL BE DISASTERS IN THE FUTURE, 17 00:00:50,700 --> 00:00:52,967 AND ONE OF THEM WILL DESTROY US. 18 00:00:52,967 --> 00:00:55,967 -- Captions by VITAC -- www.vitac.com 19 00:00:55,967 --> 00:00:59,000 CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS 20 00:01:09,067 --> 00:01:12,800 Narrator: NOT TOO HOT, NOT TOO COLD... 21 00:01:12,800 --> 00:01:16,500 WITH WATER... 22 00:01:16,500 --> 00:01:18,467 OXYGEN.... 23 00:01:18,467 --> 00:01:23,767 OUR PEACEFUL, PLENTIFUL PLANET NURTURES AND PROTECTS US... 24 00:01:23,767 --> 00:01:27,667 BUT THIS LULL WON'T LAST FOREVER. 25 00:01:27,667 --> 00:01:32,267 THERE ARE DANGERS ALL AROUND AND TROUBLE AHEAD. 26 00:01:32,267 --> 00:01:33,633 WHEN WE LOOK AROUND, 27 00:01:33,633 --> 00:01:35,600 WE THINK THAT THE UNIVERSE IS RATHER GENTLE. 28 00:01:35,600 --> 00:01:38,667 WE HAVE WARM BREEZES AND MILD SEASONS. 29 00:01:38,667 --> 00:01:42,633 ACTUALLY, THE UNIVERSE IS VIOLENT. IT IS CHAOTIC. 30 00:01:44,467 --> 00:01:46,933 Plait: THE UNIVERSE IS NOT A HAPPY, SAFE PLACE. 31 00:01:46,933 --> 00:01:48,433 THERE ARE ASTEROID IMPACTS, 32 00:01:48,433 --> 00:01:50,300 AND SOLAR FLARES, AND SUPERNOVA, AND BLACK HOLES, 33 00:01:50,300 --> 00:01:51,767 AND COLLIDING GALAXIES, 34 00:01:51,767 --> 00:01:54,900 AND ALL THESE REALLY AMAZINGLY DANGEROUS AND VIOLENT EVENTS. 35 00:01:54,900 --> 00:01:58,500 Narrator: AND THE EARTH IS IN THE CROSS HAIRS. 36 00:02:05,133 --> 00:02:06,733 DURING THE PLANET'S 37 00:02:06,733 --> 00:02:09,233 4 1/2-BILLION-YEAR EXISTENCE, 38 00:02:09,233 --> 00:02:11,400 THESE VIOLENT PHENOMENA 39 00:02:11,400 --> 00:02:13,833 HAVE WIPED OUT MILLIONS OF SPECIES 40 00:02:13,833 --> 00:02:17,567 IN A SERIES OF CATASTROPHIC MASS EXTINCTIONS. 41 00:02:17,567 --> 00:02:19,600 [ DINOSAUR ROARS ] 42 00:02:19,600 --> 00:02:22,200 MASS EXTINCTIONS DUE TO IMPACTS AND OTHER GEOLOGIC 43 00:02:22,200 --> 00:02:25,333 NATURAL PROCESSES ON THE EARTH HAVE ACTUALLY WIPED OUT 44 00:02:25,333 --> 00:02:28,100 MORE SPECIES OF PLANTS AND ANIMALS ON THE PLANET 45 00:02:28,100 --> 00:02:30,733 THAN EXIST TODAY. 46 00:02:30,733 --> 00:02:35,067 Oluseyi: MASS EXTINCTIONS ARE WHAT HAPPENS, 47 00:02:35,067 --> 00:02:36,933 IT JUST HAPPENS PERIODICALLY, 48 00:02:36,933 --> 00:02:39,667 AND WE LIVING IN THE QUIET TIME BETWEEN MASS EXTINCTIONS. 49 00:02:39,667 --> 00:02:42,967 IT'S HAPPENED BEFORE. IT'S GONNA HAPPEN AGAIN. 50 00:02:42,967 --> 00:02:45,600 Narrator: THE CLOCK IS TICKING. 51 00:02:45,600 --> 00:02:48,067 WITH EVERY DAY THAT PASSES, 52 00:02:48,067 --> 00:02:52,233 THE NEXT MASS EXTINCTION GETS A STEP CLOSER, 53 00:02:52,233 --> 00:02:55,100 AND WITH EVERY NEW DISCOVERY, 54 00:02:55,100 --> 00:02:58,367 THE UNIVERSE GETS A LITTLE BIT MORE TERRIFYING. 55 00:03:00,733 --> 00:03:03,633 NOVEMBER 2012. 56 00:03:03,633 --> 00:03:06,400 ASTRONOMERS IDENTIFY A NEW PLANET 57 00:03:06,400 --> 00:03:08,567 100 LIGHT-YEARS FROM EARTH, 58 00:03:08,567 --> 00:03:12,733 AT LEAST FOUR TIMES MORE MASSIVE THAN JUPITER, 59 00:03:12,733 --> 00:03:15,267 AND IT'S GONE ROGUE. 60 00:03:18,533 --> 00:03:21,667 UNLIKE EARTH AND ALL THE OTHER OBJECTS IN OUR SOLAR SYSTEM, 61 00:03:21,667 --> 00:03:25,400 THIS PLANET DOESN'T ORBIT A STAR. 62 00:03:25,400 --> 00:03:29,267 IT REALLY IS LOST IN SPACE. 63 00:03:29,267 --> 00:03:31,300 WHEN I WAS A KID WATCHING SCIENCE-FICTION MOVIES, 64 00:03:31,300 --> 00:03:33,367 EVERY NOW AND AGAIN THERE WOULD BE A ROGUE PLANET, 65 00:03:33,367 --> 00:03:35,333 JUST SOME PLANET WONDERING SPACE WITHOUT A STAR. 66 00:03:35,333 --> 00:03:36,900 AND I THOUGHT THAT WAS PRETTY SILLY, 67 00:03:36,900 --> 00:03:40,900 BUT IT TURNS OUT THAT MIGHT ACTUALLY HAPPEN. 68 00:03:40,900 --> 00:03:43,233 WHEN PLANETS ARE FORMING, 69 00:03:43,233 --> 00:03:45,467 THEY CAN INTERACT WITH EACH OTHER GRAVITATIONALLY. 70 00:03:45,467 --> 00:03:46,933 AND IT'S ENTIRELY POSSIBLE 71 00:03:46,933 --> 00:03:48,500 THAT WHEN OUR SOLAR SYSTEM FORMED, 72 00:03:48,500 --> 00:03:53,100 PLANETS WERE KICKED OUT INTO INTERSTELLAR SPACE. 73 00:03:53,100 --> 00:03:56,067 Narrator: THERE COULD BE AS MANY AS 200 BILLION ROGUE PLANETS 74 00:03:56,067 --> 00:03:57,633 IN OUR GALAXY. 75 00:03:57,633 --> 00:04:02,867 THAT'S AS MANY ROGUE PLANETS AS THERE ARE STARS IN THE SKY. 76 00:04:02,867 --> 00:04:06,500 AND ONE OF THEM COULD BE HEADING OUR WAY. 77 00:04:11,767 --> 00:04:15,867 A COLLISION WITH ANOTHER PLANET SOUNDS FARFETCHED. 78 00:04:15,867 --> 00:04:18,400 COULD IT REALLY HAPPEN? 79 00:04:18,400 --> 00:04:21,667 AS A MATTER OF FACT, IT ALREADY HAS. 80 00:04:25,800 --> 00:04:27,667 4 1/2 BILLION YEARS AGO, 81 00:04:27,667 --> 00:04:33,067 A YOUNG PLANET VEERS INTO THE EARTH'S ORBIT. 82 00:04:33,067 --> 00:04:34,600 WE HAVE THE EARTH SITTING HERE, 83 00:04:34,600 --> 00:04:37,067 AND ANOTHER PLANET ABOUT THE SIZE OF MARS CAME IN 84 00:04:37,067 --> 00:04:38,900 AND SMACKED US HARD. 85 00:04:41,233 --> 00:04:44,433 Narrator: THE TWO COLLIDED OVER 25,000 MILES AN HOUR, 86 00:04:44,433 --> 00:04:47,467 12 TIMES FASTER THAN A BULLET. 87 00:04:49,867 --> 00:04:53,167 THE IMPACT DESTROYS THE SMALLER PLANET. 88 00:04:53,167 --> 00:04:56,800 THE EARTH SURVIVES, BUT ONLY JUST. 89 00:04:56,800 --> 00:04:59,167 THE VIOLENCE OF THIS IS HARD TO IMAGINE. 90 00:04:59,167 --> 00:05:01,067 TWO PLANETS COMING TOGETHER 91 00:05:01,067 --> 00:05:03,467 SMASHING TOGETHER INTO ONE MOLTEN MASS. 92 00:05:03,467 --> 00:05:05,600 AFTER AN IMPACT OF THAT SCALE, 93 00:05:05,600 --> 00:05:08,867 THE ENTIRE SURFACE OF THE EARTH IS LITERALLY LIQUEFIED. 94 00:05:08,867 --> 00:05:10,933 IMAGINE THE FLOOR OF AN ACTIVE VOLCANO 95 00:05:10,933 --> 00:05:12,333 WITH ISLANDS OF SOLID ROCK 96 00:05:12,333 --> 00:05:13,867 AND LAVA SPURTING RIGHT AND LEFT. 97 00:05:13,867 --> 00:05:17,067 THE ENTIRE SURFACE OF THE PLANET WOULD'VE LOOKED LIKE THAT. 98 00:05:17,067 --> 00:05:18,867 THE EARTH ITSELF FOR A LITTLE WHILE 99 00:05:18,867 --> 00:05:21,500 WOULD'VE HAD AN ATMOSPHERE OF MOLTEN ROCK. 100 00:05:21,500 --> 00:05:23,333 AND IT WAS A, YOU KNOW, VISION OF HELL. 101 00:05:27,467 --> 00:05:31,333 Narrator: DEBRIS BLASTED OUT AT 20,000 MILES AN HOUR 102 00:05:31,333 --> 00:05:33,567 ORBITS THE MOLTEN EARTH. 103 00:05:35,900 --> 00:05:37,967 GRAVITY BRINGS THE DEBRIS TOGETHER. 104 00:05:42,767 --> 00:05:46,067 THE RESULT -- OUR MOON. 105 00:05:47,933 --> 00:05:50,200 OUR MOON EMERGED FROM THE WRECKAGE 106 00:05:50,200 --> 00:05:53,833 OF THE MOST CATACLYSMIC EVENT IN OUR PLANET'S HISTORY. 107 00:05:53,833 --> 00:05:57,400 FROM DESTRUCTION COMES CREATION, 108 00:05:57,400 --> 00:06:01,100 BECAUSE WITHOUT THIS LUMP OF COSMIC SHRAPNEL, 109 00:06:01,100 --> 00:06:04,633 LIFE ON EARTH MIGHT NEVER HAVE GAINED A FOOTHOLD. 110 00:06:04,633 --> 00:06:09,233 THE MOON'S GRAVITY PULLS ON THE INFANT EARTH'S OCEANS, 111 00:06:09,233 --> 00:06:13,800 SPREADING NUTRIENTS FROM THE LAND INTO THE WATER. 112 00:06:13,800 --> 00:06:16,067 AND IT SLOWS THE EARTH'S SPIN 113 00:06:16,067 --> 00:06:19,467 FROM A 6- TO A 24-HOUR DAY. 114 00:06:19,467 --> 00:06:22,600 IN THIS CALM, FERTILE ENVIRONMENT, 115 00:06:22,600 --> 00:06:25,633 ONE BILLION YEARS AFTER THE IMPACT, 116 00:06:25,633 --> 00:06:28,400 LIFE BEGINS. 117 00:06:28,400 --> 00:06:31,100 IF WE HADN'T HAD THAT PLANETARY COLLISION A LONG TIME AGO, 118 00:06:31,100 --> 00:06:32,967 WE WOULDN'T HAVE THE MOON TODAY. 119 00:06:32,967 --> 00:06:34,467 SO, IN FACT, 120 00:06:34,467 --> 00:06:37,400 THIS MOST CATASTROPHIC EVENT YOU CAN POSSIBLY THINK OF 121 00:06:37,400 --> 00:06:41,867 ACTUALLY MAY HAVE HELPED LIFE ON EARTH FORM IN THE FIRST PLACE 122 00:06:41,867 --> 00:06:46,067 AND HELPED US EVOLVE OVER THE NEXT COUPLE OF BILLION YEARS. 123 00:06:46,067 --> 00:06:49,333 Narrator: BUT WHAT WAS A GOOD THING IN THE PAST 124 00:06:49,333 --> 00:06:53,367 WOULD BE A DISASTER IF IT HAPPENED TODAY. 125 00:06:53,367 --> 00:06:55,833 NOW, YOU DON'T WANT A PLANETARY COLLISION NOW 126 00:06:55,833 --> 00:06:57,833 BECAUSE THAT WOULD WIPE OUT THE ENTIRE PLANET. 127 00:07:00,467 --> 00:07:02,833 YOU CAN'T EVEN DESCRIBE IT COMPARING IT TO NUCLEAR WEAPONS. 128 00:07:02,833 --> 00:07:05,067 IT WOULD BE BILLIONS OF NUCLEAR WEAPONS. 129 00:07:05,067 --> 00:07:06,667 IT'S ENOUGH TO MELT 130 00:07:06,667 --> 00:07:10,733 SEVERAL MILES THICK CRUST ON THE EARTH ALL THE WAY DOWN. 131 00:07:10,733 --> 00:07:12,133 IT WOULD WIPE OUT ALL LIFE ON EARTH. 132 00:07:12,133 --> 00:07:13,500 THAT WOULD BE IT. 133 00:07:13,500 --> 00:07:16,800 IT WOULD BE LIKE A HARD RESTART FOR THE PLANET ITSELF. 134 00:07:16,800 --> 00:07:20,333 Narrator: COULD THIS NIGHTMARE BECOME A REALITY? 135 00:07:20,333 --> 00:07:24,233 RIGHT NOW EVEN THE CLOSEST ROGUE PLANETS WE'VE DISCOVERED 136 00:07:24,233 --> 00:07:27,200 ARE STILL TRILLIONS OF MILES FROM EARTH. 137 00:07:27,200 --> 00:07:29,467 AND OUR NEIGHBORING PLANETS HAVE SETTLED 138 00:07:29,467 --> 00:07:32,800 INTO CALM, STABLE ORBITS. 139 00:07:32,800 --> 00:07:34,233 Plait: WE'RE NOT GONNA GET A PLANETARY COLLISION 140 00:07:34,233 --> 00:07:35,467 ANY TIME SOON, 141 00:07:35,467 --> 00:07:37,333 BUT ALL THE GRAVITY OF THE PLANETS 142 00:07:37,333 --> 00:07:39,533 PLAY WITH EACH OTHER AND CHANGE EACH OTHER'S ORBITS. 143 00:07:39,533 --> 00:07:42,700 SO CLEARLY IF YOU RUN THE CLOCK WORK OF TIME FORWARD 144 00:07:42,700 --> 00:07:44,333 BILLIONS OF YEARS, 145 00:07:44,333 --> 00:07:45,833 YES, IT'S ENTIRELY POSSIBLE 146 00:07:45,833 --> 00:07:47,967 THAT WE MIGHT HAVE ANOTHER PLANETARY COLLISION. 147 00:07:47,967 --> 00:07:50,933 YOU JUST DON'T HAVE TO WORRY ABOUT IT FOR A LONG, LONG TIME. 148 00:07:54,200 --> 00:07:55,800 Narrator: 4 BILLION YEARS AGO, 149 00:07:55,800 --> 00:08:00,400 A DEVASTATING COLLISION MADE LIFE ON EARTH POSSIBLE. 150 00:08:00,400 --> 00:08:03,500 2 BILLION YEARS LATER, 151 00:08:03,500 --> 00:08:06,600 THAT LIFE THREATENS TO DESTROY ITSELF. 152 00:08:22,700 --> 00:08:24,733 Narrator: OUR BLUE PLANET -- 153 00:08:24,733 --> 00:08:28,733 IN A HOSTILE UNIVERSE, IT SUSTAINS AND NURTURES LIFE. 154 00:08:31,667 --> 00:08:34,100 2.4 BILLION YEARS AGO, 155 00:08:34,100 --> 00:08:35,900 SIMPLE, SINGLE-CELLED ORGANISMS 156 00:08:35,900 --> 00:08:38,800 DRIFT THROUGH THE NUTRIENT-RICH OCEANS. 157 00:08:40,867 --> 00:08:44,433 BUT THEIR WORLD IS ABOUT TO BE DESTROYED. 158 00:08:44,433 --> 00:08:46,333 WHEN YOU TALK ABOUT MASS EXTINCTIONS, 159 00:08:46,333 --> 00:08:48,233 YOU HAVE AT LEAST TWO TYPES -- 160 00:08:48,233 --> 00:08:50,400 ONE DANGER COMING FROM OUTER SPACE, 161 00:08:50,400 --> 00:08:53,433 ANOTHER FROM OUR OWN VERY BACKYARD ON THE PLANET EARTH. 162 00:08:58,967 --> 00:09:02,100 Narrator: THE EARTH CIRCLES THE SUN, 163 00:09:02,100 --> 00:09:04,800 BUT THIS ORBIT IS UNSTABLE. 164 00:09:04,800 --> 00:09:07,367 OVER HUNDREDS OF THOUSANDS OF YEARS, 165 00:09:07,367 --> 00:09:08,867 IT CHANGES, 166 00:09:08,867 --> 00:09:11,500 SWINGING THE PLANET FURTHER OUT INTO SPACE 167 00:09:11,500 --> 00:09:13,867 AND PIVOTING ON ITS AXIS. 168 00:09:16,067 --> 00:09:21,933 TILTED AWAY FROM THE SUN, THE EARTH COOLS. 169 00:09:21,933 --> 00:09:24,067 2.4 BILLION YEARS AGO, 170 00:09:24,067 --> 00:09:27,067 SOMETHING TURNS THIS NATURAL COOLING 171 00:09:27,067 --> 00:09:30,067 INTO A GLOBAL CATASTROPHE. 172 00:09:30,067 --> 00:09:32,533 IT IS ONE OF THE MOST DANGEROUS THINGS 173 00:09:32,533 --> 00:09:35,067 IN ALL THE UNIVERSE -- 174 00:09:35,067 --> 00:09:37,300 LIFE. 175 00:09:37,300 --> 00:09:39,767 TINY ORGANISMS POPULATE THE OCEANS. 176 00:09:42,367 --> 00:09:44,200 THERE'S NO OXYGEN AROUND 177 00:09:44,200 --> 00:09:46,267 AND THAT'S THE WAY MOST OF THEM LIKE IT. 178 00:09:46,267 --> 00:09:50,333 BUT THEN A NEW KIND OF BACTERIA EVOLVES -- 179 00:09:50,333 --> 00:09:51,933 CYANOBACTERIA. 180 00:09:51,933 --> 00:09:57,367 AND THESE GUYS CREATE A SERIOUS GAS PROBLEM. 181 00:09:57,367 --> 00:09:59,267 McKay: IMAGINE EARTH BILLIONS OF YEARS AGO. 182 00:09:59,267 --> 00:10:01,300 THERE'S NO OXYGEN. EVERYBODY'S HAPPY. 183 00:10:01,300 --> 00:10:05,567 THEN CYANOBACTERIA START MAKING OXYGEN. 184 00:10:05,567 --> 00:10:07,833 IT'S A TOXIC POLLUTANT. 185 00:10:07,833 --> 00:10:09,900 IF THERE WAS A REGULATORY AGENCY AT THE TIME, 186 00:10:09,900 --> 00:10:11,200 THEY WOULD'VE BEEN OUTLAWED. 187 00:10:11,200 --> 00:10:14,300 EVENTUALLY THEY POLLUTED THE WHOLE WORLD. 188 00:10:14,300 --> 00:10:16,133 THEY HAD REALLY PRECIPITATED 189 00:10:16,133 --> 00:10:19,567 AN ECOLOGICAL CRISIS OF GLOBAL PROPORTIONS. 190 00:10:19,567 --> 00:10:21,900 Narrator: THE GREAT OXYGEN CRISIS 191 00:10:21,900 --> 00:10:25,100 UPSETS THE GREENHOUSE EFFECT THAT KEEPS THE PLANET WARM. 192 00:10:29,300 --> 00:10:32,067 GLOBAL TEMPERATURES PLUMMET. 193 00:10:32,067 --> 00:10:36,167 McKay: THE ULTIMATE CULPRIT IS BIOLOGY. 194 00:10:36,167 --> 00:10:38,133 BIOLOGY MAKES A MESS OF THE PLANET, 195 00:10:38,133 --> 00:10:39,833 PRODUCES OXYGEN. 196 00:10:39,833 --> 00:10:43,300 THE OXYGEN DESTROYS THE GREENHOUSE EFFECT OF METHANE 197 00:10:43,300 --> 00:10:44,900 AND THAT FREEZES UP THE EARTH. 198 00:10:44,900 --> 00:10:51,100 Narrator: 2.4 BILLION YEARS AGO, ICE CREEPS OUT FROM THE POLES. 199 00:10:56,700 --> 00:10:58,500 INSTEAD OF WARMING THE PLANET, 200 00:10:58,500 --> 00:11:01,167 SUNLIGHT BOUNCES OFF THE ICE, 201 00:11:01,167 --> 00:11:02,667 TEMPERATURES FALL, 202 00:11:02,667 --> 00:11:07,167 CREATING MORE ICE WHICH BOUNCES MORE SUNLIGHT BACK INTO SPACE, 203 00:11:07,167 --> 00:11:09,200 AND SO ON AND SO ON 204 00:11:09,200 --> 00:11:13,067 UNTIL THE COOLING BECOMES UNSTOPPABLE. 205 00:11:13,067 --> 00:11:15,567 THE ICE MARCHES ON. 206 00:11:15,567 --> 00:11:18,367 TEMPERATURES PLUNGE. 207 00:11:21,967 --> 00:11:25,067 THE BLUE PLANET TURNS WHITE. 208 00:11:25,067 --> 00:11:28,500 IT'S A SNOWBALL EARTH. 209 00:11:28,500 --> 00:11:31,800 AND INCREDIBLY, THIS MAY'VE HAPPENED NOT ONCE 210 00:11:31,800 --> 00:11:35,367 BUT AT LEAST THREE TIMES OVER THE FOLLOWING BILLION YEARS 211 00:11:35,367 --> 00:11:39,700 AS THE PLANET LURCHED AROUND THE SUN. 212 00:11:39,700 --> 00:11:42,633 BUT THROUGHOUT ALL OF THIS AND AGAINST ALL THE ODDS, 213 00:11:42,633 --> 00:11:45,867 A HANDFUL OF SPECIES CLUNG TO LIFE, 214 00:11:45,867 --> 00:11:48,800 THANKS TO VOLCANOES. 215 00:11:51,300 --> 00:11:55,300 EVEN IN AN EARTH THAT WAS COVERED ALMOST ENTIRELY BY ICE, 216 00:11:55,300 --> 00:11:57,767 VOLCANOES WOULD'VE BEEN PUNCHING THROUGH THAT. 217 00:11:57,767 --> 00:12:01,067 SO YOU CERTAINLY HAVE POCKETS OF WATER LYING ABOUT. 218 00:12:01,067 --> 00:12:03,200 AND LIFE WAS ABLE TO CARRY ON 219 00:12:03,200 --> 00:12:05,100 AND GET THROUGH THESE COLD PERIODS. 220 00:12:13,300 --> 00:12:15,067 Narrator: AND THE WHOLE TIME, 221 00:12:15,067 --> 00:12:17,367 THE VOLCANOES THAT HELP SUSTAIN LIFE 222 00:12:17,367 --> 00:12:20,367 HAVE BEEN PUMPING OUT CARBON DIOXIDE. 223 00:12:20,367 --> 00:12:23,067 AS THIS GREENHOUSE GAS INCREASES, 224 00:12:23,067 --> 00:12:24,567 THE ATMOSPHERE WARMS. 225 00:12:24,567 --> 00:12:27,100 UNTIL 640 MILLION YEARS AGO, 226 00:12:27,100 --> 00:12:30,600 THE LAST, GREAT SNOWBALL EARTH ENDS. 227 00:12:32,667 --> 00:12:37,567 AND THE SURVIVORS EMERGE INTO A NEW WORLD. 228 00:12:37,567 --> 00:12:41,867 AFTER SNOWBALL EARTH GOES AWAY, THINGS GET VERY INTERESTING. 229 00:12:41,867 --> 00:12:44,867 A LOT OF OPPORTUNITIES OPEN UP FOR LIFE, 230 00:12:44,867 --> 00:12:46,833 WATER'S FLOWING, ICE IS MELTING, 231 00:12:46,833 --> 00:12:49,967 ORGANIC MATERIAL BUILT UP THAT HASN'T BEEN DECOMPOSING. 232 00:12:49,967 --> 00:12:53,733 SO YOU CAN IMAGINE THAT THERE WILL BE A BURST OF DEVELOPMENT. 233 00:12:53,733 --> 00:12:56,533 Narrator: IN THE MEANTIME, 234 00:12:56,533 --> 00:13:01,367 CYANOBACTERIA HAVE BEEN CHURNING OUT EVER MORE OXYGEN. 235 00:13:01,367 --> 00:13:06,967 OTHER ORGANISMS WILL EITHER LEARN TO BREATHE IT OR DIE. 236 00:13:06,967 --> 00:13:09,167 McKay: MANY ORGANISMS DECIDED 237 00:13:09,167 --> 00:13:11,467 THAT THIS POISON COULD BE USEFUL, 238 00:13:11,467 --> 00:13:12,933 IT'S ENERGETIC, 239 00:13:12,933 --> 00:13:14,667 AND THAT ALLOWED THEM TO HAVE AN ENERGY SOURCE 240 00:13:14,667 --> 00:13:16,267 THAT WAS SO POWERFUL 241 00:13:16,267 --> 00:13:18,533 THAT THEY COULD BUILD HUGE, COMPLEX STRUCTURES -- 242 00:13:18,533 --> 00:13:19,967 POOF, ANIMALS. 243 00:13:19,967 --> 00:13:23,967 Narrator: SNOWBALL EARTH IS AN ENVIRONMENTAL DISASTER 244 00:13:23,967 --> 00:13:27,067 AND AN EVOLUTIONARY TRIUMPH. 245 00:13:27,067 --> 00:13:30,900 COMPLEX LIFE FLOURISHES. 246 00:13:37,800 --> 00:13:41,967 BUT MOST OF THESE CREATURES WILL NEVER EVOLVE BEYOND THIS POINT. 247 00:13:41,967 --> 00:13:44,600 SOMETHING STOPS THEM DEAD. 248 00:13:44,600 --> 00:13:48,100 IT IS THE MOST POWERFUL WEAPON IN THE UNIVERSE, 249 00:13:48,100 --> 00:13:51,300 AND IT STRIKES IN THE BLINK OF AN EYE. 250 00:14:03,167 --> 00:14:05,800 Narrator: IN A VIOLENT UNIVERSE, 251 00:14:05,800 --> 00:14:08,933 AGAINST ALL THE ODDS, LIFE SURVIVES. 252 00:14:08,933 --> 00:14:10,867 BUT CONSIDER THIS -- 253 00:14:10,867 --> 00:14:14,100 AT ANY MOMENT, THE UNIVERSE COULD PULL THE TRIGGER 254 00:14:14,100 --> 00:14:17,900 ON A SECRET, DEEP-SPACE DEATH RAY, 255 00:14:17,900 --> 00:14:20,533 OBLITERATING ALL LIFE ON EARTH. 256 00:14:20,533 --> 00:14:25,767 AND UNTIL THE 1960s, NOBODY EVEN KNEW IT EXISTED. 257 00:14:28,533 --> 00:14:33,100 1967 -- THE HEIGHT OF THE COLD WAR. 258 00:14:33,100 --> 00:14:35,200 THE UNITED STATES AND SOVIET UNION 259 00:14:35,200 --> 00:14:37,133 RACED TO OUTGUN EACH OTHER, 260 00:14:37,133 --> 00:14:40,500 STOCKPILING AND TESTING NUCLEAR WEAPONS. 261 00:14:40,500 --> 00:14:43,067 AMERICA WAS WORRIED THAT THE SOVIET UNION 262 00:14:43,067 --> 00:14:46,067 WOULD BE ABLE TO TEST NUCLEAR WEAPONS IN SPACE. 263 00:14:46,067 --> 00:14:48,300 SO WHAT AMERICA DID IS LAUNCH THE SERIES OF SATELLITES 264 00:14:48,300 --> 00:14:50,767 TO GO OUT INTO SPACE AND LOOK FOR THE TELL-TALE FLASH 265 00:14:50,767 --> 00:14:53,467 OF GAMMA RAYS FROM NUCLEAR TESTS. 266 00:14:53,467 --> 00:14:55,733 Narrator: ON JULY 2, 1967, 267 00:14:55,733 --> 00:14:59,200 THE SATELLITES DETECT A BURST OF GAMMA RAYS, 268 00:14:59,200 --> 00:15:01,867 THE MOST ENERGETIC AND DESTRUCTIVE FORM 269 00:15:01,867 --> 00:15:05,067 OF ELECTROMAGNETIC RADIATION. 270 00:15:05,067 --> 00:15:07,467 IMMEDIATELY THERE WAS PANIC IN THE PENTAGON. 271 00:15:07,467 --> 00:15:09,333 PERHAPS THE RUSSIANS ARE TESTING 272 00:15:09,333 --> 00:15:11,900 SUPER-GIGANTIC HYDROGEN BOMBS IN OUTER SPACE. 273 00:15:11,900 --> 00:15:14,500 AND WE'RE JUST CAUGHT FLAT-FOOTED. 274 00:15:14,500 --> 00:15:16,633 Narrator: BUT IT'S NOT BOMBS. 275 00:15:16,633 --> 00:15:19,167 IT'S SOMETHING FAR DEADLIER. 276 00:15:19,167 --> 00:15:21,467 Kaku: AND THEN THE REALIZATION SUNK IN. 277 00:15:21,467 --> 00:15:23,300 "OH, MY GOD. 278 00:15:23,300 --> 00:15:28,467 "THESE FLASHES ARE COMING FROM OUTSIDE THE MILKY WAY GALAXY. 279 00:15:28,467 --> 00:15:31,733 THEY MUST BE BILLIONS OF LIGHT-YEARS AWAY." 280 00:15:31,733 --> 00:15:33,367 A NEW SOURCE OF ENERGY, 281 00:15:33,367 --> 00:15:36,700 SECOND ONLY TO THE BIG BANG ITSELF HAD BEEN DISCOVERED. 282 00:15:36,700 --> 00:15:39,067 WHEN GAMMA RAY AT FIRST WERE FIRST DISCOVERED, 283 00:15:39,067 --> 00:15:42,067 PEOPLE ASSUMED THAT THEY MUST BE FAIRLY CLOSE BY. 284 00:15:42,067 --> 00:15:43,467 "OF COURSE THEY HAVE TO BE CLOSE BY. 285 00:15:43,467 --> 00:15:46,167 THEY'RE THE BRIGHTEST THING THAT WE SEE IN THE SKY." 286 00:15:46,167 --> 00:15:47,933 AND NOW WE KNOW THAT GAMMA RAY BURST, 287 00:15:47,933 --> 00:15:49,367 NOT ONLY ARE THEY NOT NEARBY, 288 00:15:49,367 --> 00:15:51,867 THEY'RE NOT IN OUR GALAXY, THEY'RE NOT IN NEARBY GALAXIES, 289 00:15:51,867 --> 00:15:53,833 BUT THEY'RE CLOSE TO THE EDGE OF THE UNIVERSE. 290 00:15:53,833 --> 00:15:56,500 THEY'RE AS FAR AWAY AS ANYTHING ELSE THAT WE OBSERVE, 291 00:15:56,500 --> 00:15:58,267 AND THAT'S COMPLETELY RIDICULOUS. 292 00:15:58,267 --> 00:16:00,733 Narrator: OVER DISTANCE, LIGHT GETS DIMMER. 293 00:16:00,733 --> 00:16:04,733 THE FURTHER LIGHT HAS TO TRAVEL, THE DIMMER THE LIGHT SHOULD BE. 294 00:16:04,733 --> 00:16:07,167 IF LIGHT FROM A DISTANT GALAXY COMES TO EARTH 295 00:16:07,167 --> 00:16:09,433 AND IT HAS GAMMA-RAY ENERGIES, 296 00:16:09,433 --> 00:16:11,933 THEN THAT EXPLOSION MUST'VE BEEN INCREDIBLY POWERFUL, 297 00:16:11,933 --> 00:16:15,900 BECAUSE IT TURNS OUT THAT AS LIGHT TRAVELS THROUGH SPACE, 298 00:16:15,900 --> 00:16:18,100 THE WAVE LENGTH OF THE LIGHT GETS STRETCHED OUT. 299 00:16:18,100 --> 00:16:20,733 AND THIS STRETCHING CAUSED THE LIGHT TO LOSE ENERGY. 300 00:16:20,733 --> 00:16:24,633 AND SINCE THE LIGHT RAYS HAVE TRAVELED A VERY GREAT DISTANCE 301 00:16:24,633 --> 00:16:26,300 THROUGH THE COSMOS TO REACH US, 302 00:16:26,300 --> 00:16:28,100 AND THEY'RE STILL GAMMA RAYS, 303 00:16:28,100 --> 00:16:31,333 THEY MUST'VE STARTED OUT WITH A GREAT DEAL OF ENERGY. 304 00:16:31,333 --> 00:16:33,067 AND THE AMOUNT OF ENERGIES ARE UNBELIEVABLE. 305 00:16:33,067 --> 00:16:36,067 YOU'RE TALKING ABOUT THE ENTIRE ENERGY BUDGET OF THE SUN 306 00:16:36,067 --> 00:16:37,433 OVER ITS WHOLE LIFETIME 307 00:16:37,433 --> 00:16:40,500 EMITTED OVER THE COURSE OF JUST A FEW SECONDS. 308 00:16:40,500 --> 00:16:44,333 THESE ARE AMAZINGLY VIOLENT, AMAZINGLY POWERFUL EVENTS. 309 00:16:44,333 --> 00:16:46,067 [ RADIO STATIC ] 310 00:16:46,067 --> 00:16:48,167 Narrator: IN JUNE 2008. 311 00:16:48,167 --> 00:16:51,233 NASA LAUNCHES THE FERMI SPACE TELESCOPE. 312 00:16:53,067 --> 00:16:54,300 ITS MISSION -- 313 00:16:54,300 --> 00:16:58,167 DISCOVER THE SOURCE OF THESE HUGE BLASTS. 314 00:16:58,167 --> 00:16:59,767 McEnery: WHAT FERMI DOES 315 00:16:59,767 --> 00:17:02,200 IS OPEN OUR EYES TO THE UNIVERSE THAT'S THERE 316 00:17:02,200 --> 00:17:03,967 BUT GIVES US SUCH A DIFFERENT VIEW 317 00:17:03,967 --> 00:17:06,467 THAT WE REALLY GET A DEEPER AND GREATER UNDERSTANDING 318 00:17:06,467 --> 00:17:07,767 OF WHAT'S GOING ON. 319 00:17:07,767 --> 00:17:09,533 IF YOU HAD GAMMA-RAY EYES, 320 00:17:09,533 --> 00:17:12,133 THE MILKY WAY WOULD BE BLAZINGLY BRIGHT 321 00:17:12,133 --> 00:17:15,233 ACROSS THE CENTER OF THE SKY. 322 00:17:15,233 --> 00:17:17,367 YOUR VISION WOULD BE DOMINATED 323 00:17:17,367 --> 00:17:20,400 BY THESE VERY DENSE, PULSING STARS 324 00:17:20,400 --> 00:17:21,867 AND SUPER-MASSIVE BLACK HOLES. 325 00:17:21,867 --> 00:17:25,067 Narrator: AND IT'S BLACK HOLES 326 00:17:25,067 --> 00:17:28,533 THAT MAY SOLVE THE MYSTERY OF GAMMA-RAY BURSTS. 327 00:17:28,533 --> 00:17:31,500 WHEN A TRULY GIGANTIC STAR DIES, 328 00:17:31,500 --> 00:17:35,133 ONE AT LEAST 25 TIMES MORE MASSIVE THAN OUR OWN SUN, 329 00:17:35,133 --> 00:17:39,200 IT COLLAPSES TO FORM A BLACK HOLE. 330 00:17:39,200 --> 00:17:41,167 SCIENTISTS BELIEVE BLACK HOLES 331 00:17:41,167 --> 00:17:43,267 ARE ONE OF THE FEW THINGS IN THE UNIVERSE 332 00:17:43,267 --> 00:17:49,233 LARGE ENOUGH AND POWERFUL ENOUGH TO GENERATE GAMMA-RAY BURSTS. 333 00:17:49,233 --> 00:17:52,867 Plait: GAMMA-RAY BURSTS ARE THE BIRTH CRIES OF BLACK HOLES. 334 00:17:52,867 --> 00:17:56,633 WHEN A MASSIVE STAR EXPLODES AND BECOMES A SUPERNOVA, 335 00:17:56,633 --> 00:17:59,200 THE CORE COLLAPSES AND FORMS A BLACK HOLE. 336 00:17:59,200 --> 00:18:02,567 MATERIAL FALLS AROUND IT, SWIRLS INTO A HUGE DISK, 337 00:18:02,567 --> 00:18:04,533 IT GETS INCREDIBLY HOT. 338 00:18:04,533 --> 00:18:06,067 AS IT'S FALLING INTO THE BLACK HOLE 339 00:18:06,067 --> 00:18:08,933 IT FORMS A TREMENDOUS MAGNETIC FIELD, AS WELL. 340 00:18:17,100 --> 00:18:18,867 Narrator: THE REMAINS OF THE STAR 341 00:18:18,867 --> 00:18:22,233 SPIRAL TOWARDS THE BLACK HOLE. 342 00:18:22,233 --> 00:18:24,967 ENORMOUS ELECTROMAGNETIC FORCES 343 00:18:24,967 --> 00:18:28,533 FLING SOME OF THIS MATTER OUTWARDS. 344 00:18:28,533 --> 00:18:31,733 HURTLING UP AND DOWN 345 00:18:31,733 --> 00:18:33,300 THE BLACK HOLE'S HUGE MAGNETIC FIELDS, 346 00:18:33,300 --> 00:18:37,400 THE MATTER COLLIDES WITH DEBRIS FROM THE INITIAL EXPLOSION, 347 00:18:37,400 --> 00:18:40,167 ACCELERATING TO CLOSE TO THE SPEED OF LIGHT, 348 00:18:40,167 --> 00:18:43,467 HEATING TO MILLIONS OF DEGREES. 349 00:18:43,467 --> 00:18:45,500 THESE HIGH-SPEED COLLISIONS 350 00:18:45,500 --> 00:18:49,067 UNLEASH UNIMAGINABLE AMOUNTS OF ENERGY. 351 00:18:49,067 --> 00:18:52,667 THIS IS THE GAMMA-RAY BURST. 352 00:18:52,667 --> 00:18:55,867 Gehrels: GAMMA-RAY BURSTS ARE FASCINATING. 353 00:18:55,867 --> 00:18:57,567 YOU CAN STUDY THEM THROUGHOUT THE UNIVERSE 354 00:18:57,567 --> 00:18:58,867 BECAUSE THEY'RE SO BRIGHT. 355 00:18:58,867 --> 00:19:02,667 BUT IF YOU MOVE THEM IN REALLY CLOSE TO THE EARTH, 356 00:19:02,667 --> 00:19:05,733 LET'S SAY WITHIN 6,000 LIGHT-YEARS OF THE EARTH, 357 00:19:05,733 --> 00:19:08,100 THEY BECOME EXTREMELY DESTRUCTIVE. 358 00:19:08,100 --> 00:19:11,467 Narrator: THE BEAMS ARE SO HUGE THAT IF A GAMMA-RAY BURST 359 00:19:11,467 --> 00:19:16,100 OCCURS, SAY, 100 LIGHT-YEARS FROM US, 360 00:19:16,100 --> 00:19:18,633 BY THE TIME IT REACHES THE EARTH, THE BEAM WILL BE 361 00:19:18,633 --> 00:19:22,600 WIDE ENOUGH TO ENGULF OUR ENTIRE SOLAR SYSTEM. 362 00:19:22,600 --> 00:19:25,133 BASICALLY, IF YOU WERE STANDING ON THE EARTH AND YOU LOOKED UP, 363 00:19:25,133 --> 00:19:26,667 YOU WOULD SEE A FLASH OF LIGHT, 364 00:19:26,667 --> 00:19:29,133 AND BEFORE YOU COULD EVEN SAY, "WHAT'S THAT?" 365 00:19:29,133 --> 00:19:30,533 YOU'D BE GONE. 366 00:19:30,533 --> 00:19:33,900 THE AMOUNT OF ENERGY IN THE BEAM THAT TRAVELS ACROSS SPACE 367 00:19:33,900 --> 00:19:36,500 IS SO INTENSE IT WOULD BASICALLY LIGHT THE EARTH ON FIRE 368 00:19:36,500 --> 00:19:38,267 FROM THAT DISTANCE. 369 00:19:38,267 --> 00:19:40,100 IT WOULD STRIP OFF THE EARTH'S ATMOSPHERE, 370 00:19:40,100 --> 00:19:43,067 IT WOULD BOIL THE OCEANS, IT WOULD MELT THE ROCK. 371 00:19:43,067 --> 00:19:46,067 IT WOULD BE APOCALYPTIC BEYOND APOCALYPTIC. 372 00:19:48,467 --> 00:19:52,100 Narrator: THIS IS THE WORST-CASE SCENARIO. 373 00:19:52,100 --> 00:19:56,233 BUT WHAT IF A GAMMA-RAY BURST HIT THE EARTH FROM FURTHER OUT? 374 00:19:56,233 --> 00:19:58,733 WOULD WE SURVIVE? 375 00:19:58,733 --> 00:20:01,300 PEOPLE ASK WHAT WOULD HAPPEN IF THERE WAS A GAMMA-RAY BURST 376 00:20:01,300 --> 00:20:04,000 WITHIN 6,000 LIGHT-YEARS OF THE EARTH. 377 00:20:04,000 --> 00:20:05,867 IT'S ACTUALLY NOT THE RIGHT QUESTION. 378 00:20:05,867 --> 00:20:08,767 THERE HAVE BEEN GAMMA-RAY BURSTS THAT CLOSE TO THE EARTH, 379 00:20:08,767 --> 00:20:12,033 AND THERE PROBABLY HAVE BEEN EXTINCTIONS OF LIFE ON EARTH 380 00:20:12,033 --> 00:20:14,100 DUE TO GAMMA-RAY BURSTS. 381 00:20:16,100 --> 00:20:19,533 Narrator: 200 MILLION YEARS AFTER SNOWBALL EARTH, 382 00:20:19,533 --> 00:20:23,167 THE OCEANS ARE TEEMING WITH COMPLEX LIFE. 383 00:20:23,167 --> 00:20:26,800 BUT 440 MILLION YEARS AGO, 384 00:20:26,800 --> 00:20:30,167 85% OF ALL THOSE CREATURES DIED. 385 00:20:32,933 --> 00:20:35,000 AND THE KILLER MAY HAVE BEEN 386 00:20:35,000 --> 00:20:38,633 A SINGLE DEVASTATING GAMMA-RAY BURST. 387 00:20:38,633 --> 00:20:42,233 THE BLAST PENETRATES THE OCEANS' UPPER LAYERS, 388 00:20:42,233 --> 00:20:45,100 KILLING THE CREATURES THAT LIVE NEAR THE SURFACE. 389 00:20:45,100 --> 00:20:51,400 CREATURES LIVING FURTHER DOWN SURVIVE THE INITIAL ONSLAUGHT, 390 00:20:51,400 --> 00:20:54,433 BUT NOT FOR LONG... 391 00:20:54,433 --> 00:20:58,667 BECAUSE THE BLAST ALSO DAMAGES THE EARTH'S OZONE LAYER, 392 00:20:58,667 --> 00:21:02,933 EXPOSING THE PLANET TO THE SUN'S DEADLY UV RADIATION, 393 00:21:02,933 --> 00:21:05,167 TRIGGERING ACID RAIN 394 00:21:05,167 --> 00:21:07,800 AND LOWERING GLOBAL TEMPERATURES. 395 00:21:07,800 --> 00:21:10,467 OVER HALF A MILLION YEARS, 396 00:21:10,467 --> 00:21:13,333 THE CREATURES THAT SURVIVED THE GAMMA-RAY BURST 397 00:21:13,333 --> 00:21:16,600 GET TAKEN OUT BY ITS AFTER EFFECTS. 398 00:21:16,600 --> 00:21:21,067 IF A GAMMA-RAY BURST HAS WIPED OUT LIFE IN THE PAST, 399 00:21:21,067 --> 00:21:22,900 IT COULD HAPPEN IN THE FUTURE. 400 00:21:26,467 --> 00:21:28,600 AND ASTRONOMERS THINK THE NEXT BURST 401 00:21:28,600 --> 00:21:35,100 COULD COME FROM A DANGEROUSLY UNSTABLE STAR, WR 104. 402 00:21:35,100 --> 00:21:38,400 Kaku: WR 104 IS THE NIGHTMARE. 403 00:21:38,400 --> 00:21:41,067 WE NOW HAVE A POTENTIAL CANDIDATE 404 00:21:41,067 --> 00:21:45,233 FOR WHAT MAY BECOME A GAMMA-RAY BURSTER WITH OUR NAME ON IT. 405 00:21:45,233 --> 00:21:49,467 WE ARE LITERALLY STARING DOWN THE GUN BARREL OF WR 104. 406 00:21:53,067 --> 00:21:54,500 Narrator: IT'S NOT ONE 407 00:21:54,500 --> 00:21:58,733 BUT TWO MASSIVE STARS ORBITING EACH OTHER. 408 00:22:00,500 --> 00:22:04,467 THE STARS WILL DIE IN A MASSIVE EXPLOSION, 409 00:22:04,467 --> 00:22:06,200 SPAWNING A BLACK HOLE, 410 00:22:06,200 --> 00:22:08,567 AND BLASTING OUT GAMMA RAYS. 411 00:22:11,100 --> 00:22:13,400 Kaku: THE OBJECT IS ABOUT 8,000 LIGHT-YEARS AWAY, 412 00:22:13,400 --> 00:22:17,500 SO WE ARE WITHIN THE KILL RADIUS OF THIS OBJECT. 413 00:22:17,500 --> 00:22:19,800 SO YOU COULD BE DOING YOUR LAUNDRY TOMORROW, 414 00:22:19,800 --> 00:22:21,867 LOOK UP IN THE SKY, AND ALL OF A SUDDEN, 415 00:22:21,867 --> 00:22:26,267 THERE'S THIS BURST OF RADIATION RAINING DOWN FROM THE HEAVENS. 416 00:22:26,267 --> 00:22:29,467 Narrator: THE RADIATION RIPS OFF THE EARTH'S OZONE LAYER, 417 00:22:29,467 --> 00:22:31,800 CREATING A TOXIC SMOG 418 00:22:31,800 --> 00:22:34,900 AND EXPOSING US TO THE SUN'S DEADLY RAYS. 419 00:22:34,900 --> 00:22:38,267 Kaku: LIFE AS WE KNOW IT COULD CEASE TO EXIST. 420 00:22:38,267 --> 00:22:40,067 PLANTS WOULD BE SCORCHED, 421 00:22:40,067 --> 00:22:42,300 ANIMALS, WHICH DEPEND UPON PLANT LIFE, 422 00:22:42,300 --> 00:22:43,900 WILL THEN BEGIN TO DIE. 423 00:22:43,900 --> 00:22:47,700 HUMAN CIVILIZATION WOULD HAVE TO GO UNDERGROUND. 424 00:22:47,700 --> 00:22:49,267 IT MAY SOUND LIKE THE DEATH STAR 425 00:22:49,267 --> 00:22:51,067 DESTROYING THE EARTH IN "STAR WARS," 426 00:22:51,067 --> 00:22:54,300 BUT THE DIFFERENCE IS THE DEATH STAR ISN'T GONNA HAPPEN, 427 00:22:54,300 --> 00:22:56,733 A GAMMA-RAY BURST MIGHT. 428 00:23:02,867 --> 00:23:06,233 Narrator: OUR EXTINCTION COULD HAPPEN AT ANY TIME. 429 00:23:06,233 --> 00:23:10,867 AND THE FATAL BLOW DOESN'T HAVE TO COME FROM SPACE. 430 00:23:10,867 --> 00:23:13,933 IT COULD COME FROM THE VERY THING 431 00:23:13,933 --> 00:23:16,300 THAT MAKES LIFE POSSIBLE -- 432 00:23:16,300 --> 00:23:19,067 THE EARTH ITSELF. 433 00:23:32,733 --> 00:23:37,067 Narrator: OUR PLANET CONCEALS A WEAPON OF MASS EXTINCTION, 434 00:23:37,067 --> 00:23:40,333 PRIMED TO DETONATE AT ANY MOMENT, 435 00:23:40,333 --> 00:23:43,167 HIDDEN DEEP BENEATH OUR FEET. 436 00:23:45,233 --> 00:23:48,633 UNLEASHED, THE HEAT INSIDE OUR PLANET 437 00:23:48,633 --> 00:23:52,833 COULD WIPE OUT EVERYTHING IN ITS PATH ON A MASSIVE SCALE. 438 00:23:55,700 --> 00:23:58,533 200 MILLION YEARS AFTER A GAMMA-RAY BURST 439 00:23:58,533 --> 00:24:00,967 MAY HAVE DEVASTATED LIFE IN THE OCEANS, 440 00:24:00,967 --> 00:24:03,433 THE SURVIVORS HAVE COLONIZED THE LAND. 441 00:24:03,433 --> 00:24:04,767 [ CREATURES ROARING ] 442 00:24:04,767 --> 00:24:08,900 AMONG THEM, A MOTLEY CREW OF MONSTER REPTILES -- 443 00:24:08,900 --> 00:24:12,200 SCUTOSAURUS AND GORGONOPSIANS. 444 00:24:12,200 --> 00:24:16,067 THEY'RE SUCCESSFUL, STRONG, AND DOOMED. 445 00:24:16,067 --> 00:24:17,867 [ CREATURE ROARS ] 446 00:24:17,867 --> 00:24:20,100 Jerram: AROUND ABOUT 250 MILLION YEARS AGO MARKS 447 00:24:20,100 --> 00:24:23,600 THE BIGGEST MASS EXTINCTION THAT THE EARTH HAS EVER SEEN, 448 00:24:23,600 --> 00:24:26,300 THE END-PERMIAN EXTINCTION. 449 00:24:26,300 --> 00:24:28,267 JUST OVER 90% OF MARINE FAUNA 450 00:24:28,267 --> 00:24:31,133 AND AROUND ABOUT 70% OF LAND FAUNA 451 00:24:31,133 --> 00:24:33,833 DISAPPEARED FROM THE PLANET. 452 00:24:33,833 --> 00:24:36,233 Narrator: THE KILLER IS A VOLCANIC ERUPTION -- 453 00:24:36,233 --> 00:24:38,400 THE BIGGEST AND MOST CATASTROPHIC 454 00:24:38,400 --> 00:24:40,067 THE WORLD HAS EVER SEEN. 455 00:24:44,967 --> 00:24:47,333 250 MILLION YEARS AGO, 456 00:24:47,333 --> 00:24:49,367 IN WHAT IS NOW SIBERIA, 457 00:24:49,367 --> 00:24:52,433 THE EARTH'S CRUST RUPTURES, 458 00:24:52,433 --> 00:24:54,800 PUSHED BEYOND BREAKING POINT 459 00:24:54,800 --> 00:24:57,433 BY A VAST PLUME OF HOT MAGMA 460 00:24:57,433 --> 00:25:00,300 SURGING UP FROM DEEP INSIDE THE PLANET. 461 00:25:04,767 --> 00:25:07,300 Durda: THE EARTH ITSELF CAN INTERNALLY GENERATE 462 00:25:07,300 --> 00:25:10,067 SOME VERY DEVASTATING EVENTS, MILLIONS-OF-YEARS-LONG EVENTS 463 00:25:10,067 --> 00:25:12,667 IN THE FORM OF MAJOR VOLCANIC ERUPTIONS 464 00:25:12,667 --> 00:25:15,767 AT THE CONTINENT-SCALE LEVEL. 465 00:25:15,767 --> 00:25:18,433 THESE ARE BASALTIC-VOLCANISM EVENTS 466 00:25:18,433 --> 00:25:22,800 THAT FLOOD ENTIRE PORTIONS OF THE PLANET WITH BASALT LAVA. 467 00:25:24,633 --> 00:25:29,200 Narrator: LAVA SPEWS FOR TWO MILLION YEARS. 468 00:25:29,200 --> 00:25:33,633 THERE'S ENOUGH LAVA TO COVER THE ENTIRE UNITED STATES 469 00:25:33,633 --> 00:25:36,400 BENEATH A THOUSAND FEET. 470 00:25:36,400 --> 00:25:40,200 AND THE DEATH TOLL EXTENDS AROUND THE EARTH... 471 00:25:42,933 --> 00:25:45,833 ...AND DEEP INTO THE OCEANS. 472 00:25:45,833 --> 00:25:48,533 THE QUESTION IS WHY. 473 00:25:51,367 --> 00:25:55,067 THE ANSWER LIES WITH THE MOST VOLCANIC COUNTRY ON EARTH -- 474 00:25:57,500 --> 00:25:58,800 ICELAND -- 475 00:25:58,800 --> 00:26:04,300 WITH A SIMILAR, SMALLER ERUPTION JUST 230 YEARS AGO. 476 00:26:06,433 --> 00:26:09,067 JUNE 1783. 477 00:26:09,067 --> 00:26:12,767 A TERRIBLE CHAIN OF EVENTS UNFOLD 478 00:26:12,767 --> 00:26:15,133 THAT WILL DEVASTATE ICELAND 479 00:26:15,133 --> 00:26:18,733 AND KILL UP TO A MILLION PEOPLE AROUND THE WORLD. 480 00:26:18,733 --> 00:26:21,767 NEAR THE VILLAGE OF LAKI, 481 00:26:21,767 --> 00:26:27,267 A 17-MILE-LONG TEAR OPENS UP IN THE EARTH'S CRUST. 482 00:26:27,267 --> 00:26:30,267 Jerram: THESE HOLES AND CRACKS IN THE GROUND THAT YOU CAN SEE, 483 00:26:30,267 --> 00:26:31,800 THEY WOULD'VE HAD JETS OF MAGMA, 484 00:26:31,800 --> 00:26:34,633 JETS OF LAVA FLYING UP INTO THE SKY. 485 00:26:39,100 --> 00:26:40,600 TO GIVE YOU AN IDEA OF SCALE, 486 00:26:40,600 --> 00:26:43,067 THE OVERALL THE AMOUNT OF MATERIAL THAT CAME OUT OF LAKI 487 00:26:43,067 --> 00:26:46,600 IS ABOUT 3 1/2 CUBIC MILES OF VOLCANIC MATERIAL, 488 00:26:46,600 --> 00:26:48,733 AND THAT'S A LOT MATERIAL. 489 00:26:48,733 --> 00:26:52,133 AND IT'S NOT JUST THE SIZE OF LAKI THAT MAKES IT SO SPECIAL, 490 00:26:52,133 --> 00:26:55,867 IT'S ACTUALLY WHAT'S INSIDE THIS AND WHAT CAME OUT OF THIS 491 00:26:55,867 --> 00:26:57,367 THAT'S THE DANGEROUS THING. 492 00:26:57,367 --> 00:26:59,533 BECAUSE IT HAD LOTS OF SULFUR GASES 493 00:26:59,533 --> 00:27:00,867 ASSOCIATED WITH THE ERUPTION 494 00:27:00,867 --> 00:27:04,200 AND ALSO LOTS OF FLUORINE, QUITE POISONOUS GASES. 495 00:27:04,200 --> 00:27:09,267 Narrator: SULFUR DIOXIDE SPREADS OUT AROUND THE ATMOSPHERE. 496 00:27:09,267 --> 00:27:11,933 ITS DROPLETS FORM A GIANT MIRROR 497 00:27:11,933 --> 00:27:16,067 REFLECTING THE SUN'S WARMTH AWAY FROM THE EARTH. 498 00:27:16,067 --> 00:27:17,700 IT'S CLEAR THAT EVEN 499 00:27:17,700 --> 00:27:20,533 A RELATIVELY SMALL ERUPTION LIKE LAKI 500 00:27:20,533 --> 00:27:23,600 CAN CAUSE BIG, DRAMATIC EFFECTS IN TERMS OF THE CLIMATE. 501 00:27:23,600 --> 00:27:25,700 IN THE NORTHERN U.S., 502 00:27:25,700 --> 00:27:27,567 THERE WAS ONE OF THE COLDEST WINTERS EVER RECORDED. 503 00:27:27,567 --> 00:27:30,267 IN FACT, THE MISSISSIPPI IS RECORDED TO HAVE FROZEN. 504 00:27:30,267 --> 00:27:33,933 IT'S BEEN IMPLICATED IN CAUSING THE BIG FAMINE IN JAPAN. 505 00:27:33,933 --> 00:27:37,667 SO, THE EFFECTS, POTENTIALLY, FOR VOLCANOES 506 00:27:37,667 --> 00:27:39,300 THAT SPEW THESE HORRIBLE GASES 507 00:27:39,300 --> 00:27:43,067 INTO THE ATMOSPHERE CAN BE CATASTROPHIC ON A GLOBAL SCALE. 508 00:27:43,067 --> 00:27:46,767 Narrator: NOW PICTURE THE SIBERIAN ERUPTIONS 509 00:27:46,767 --> 00:27:49,100 250 MILLION YEARS AGO. 510 00:27:49,100 --> 00:27:52,833 THEY'RE 200,000 TIMES LARGER THAN LAKI 511 00:27:52,833 --> 00:27:56,067 AND LAST A MILLION TIMES LONGER. 512 00:27:56,067 --> 00:27:59,567 THEY RELEASE MASSIVE QUANTITIES OF GAS 513 00:27:59,567 --> 00:28:02,133 TRIGGERING EXTREME CLIMATE CHANGE -- 514 00:28:02,133 --> 00:28:05,300 FIRST COOLING, THEN HEATING THE ATMOSPHERE. 515 00:28:07,600 --> 00:28:10,833 70 % OF ALL LAND-BASED CREATURES DIE, 516 00:28:10,833 --> 00:28:15,667 INCLUDING THE MIGHTY GORGONOPSIANS AND SCUTOSAURUS. 517 00:28:15,667 --> 00:28:18,400 BUT WORSE IS TO COME. 518 00:28:18,400 --> 00:28:23,567 AS THE OCEANS WARM, THEY LOSE OXYGEN AND STAGNATE. 519 00:28:23,567 --> 00:28:25,733 TOXIC ALGAE TAKES OVER, 520 00:28:25,733 --> 00:28:28,933 POISONING THE OCEANS WITH HYDROGEN SULFIDE, 521 00:28:28,933 --> 00:28:32,067 KILLING 96% OF MARINE LIFE, 522 00:28:32,067 --> 00:28:35,433 AND LEAVING PURPLE SULFUR BACTERIA 523 00:28:35,433 --> 00:28:37,500 TO OVERRUN THE OCEANS, 524 00:28:37,500 --> 00:28:40,200 TURNING THE WATER PINK. 525 00:28:40,200 --> 00:28:43,567 THIS IS THE CLOSEST THE EARTH HAS EVER COME 526 00:28:43,567 --> 00:28:46,067 TO TOTAL EXTINCTION. 527 00:28:47,167 --> 00:28:51,600 BUT OVER 200 MILLION YEARS, THE SURVIVORS ADAPT AND EVOLVE. 528 00:28:51,600 --> 00:28:54,600 A NEW GROUP OF ANIMALS EMERGE. 529 00:28:54,600 --> 00:28:57,700 THEY ARE THE LARGEST, MOST SUCCESSFUL CREATURES 530 00:28:57,700 --> 00:28:59,533 THE EARTH HAS EVER SEEN -- 531 00:28:59,533 --> 00:29:01,933 THE DINOSAURS. 532 00:29:01,933 --> 00:29:06,867 BUT THEY, TOO, WILL FACE ANNIHILATION. 533 00:29:15,833 --> 00:29:18,700 Narrator: COSMIC KILLERS PROWL THE UNIVERSE 534 00:29:18,700 --> 00:29:20,933 THREATENING TO WIPE OUT LIFE ON EARTH. 535 00:29:23,533 --> 00:29:25,533 THEY'VE STRUCK BEFORE, 536 00:29:25,533 --> 00:29:29,100 PUSHING LIFE TO THE EDGE OF EXTINCTION. 537 00:29:29,100 --> 00:29:32,100 THEY WILL STRIKE AGAIN, 538 00:29:32,100 --> 00:29:34,800 AND IT COULD HAPPEN BEFORE YOU'VE FINISHED 539 00:29:34,800 --> 00:29:36,067 WATCHING THIS SHOW. 540 00:29:40,533 --> 00:29:44,300 FEBRUARY 15, 2013. 541 00:29:44,300 --> 00:29:46,600 9:42 a.m. 542 00:29:46,600 --> 00:29:48,633 IT'S ANOTHER COLD WINTER'S DAY 543 00:29:48,633 --> 00:29:51,267 IN THE SIBERIAN CITY OF CHELYABINSK 544 00:29:51,267 --> 00:29:56,900 WHEN LITERALLY, OUT OF THE BLUE... 545 00:29:56,900 --> 00:30:01,667 A 14,000-TON, 65-FOOT METEOR 546 00:30:01,667 --> 00:30:06,167 TEARS THROUGH THE ATMOSPHERE AT 42,000 MILES AN HOUR. 547 00:30:06,167 --> 00:30:09,800 IT EXPLODES IN THE AIR 18 MILES UP, 548 00:30:09,800 --> 00:30:12,833 UNLEASHING A POWERFUL BLAST WAVE, 549 00:30:12,833 --> 00:30:15,333 SHATTERING WINDOWS, 550 00:30:15,333 --> 00:30:17,833 DAMAGING 7,000 BUILDINGS, 551 00:30:17,833 --> 00:30:20,333 AND INJURING 1,500 PEOPLE. 552 00:30:20,333 --> 00:30:23,867 NOW IMAGINE WHAT WOULD'VE HAPPENED 553 00:30:23,867 --> 00:30:27,133 IF THE ASTEROID HAD HIT THE EARTH IN ONE PIECE. 554 00:30:27,133 --> 00:30:29,933 AND WE SAW WHAT HAPPENED OVER RUSSIA, 555 00:30:29,933 --> 00:30:31,400 OVER IN CHELYABINSK, 556 00:30:31,400 --> 00:30:34,100 WITH AN OBJECT THAT COULD HAVE HIT THE EARTH -- 557 00:30:34,100 --> 00:30:35,733 COULD'VE HIT THE EARTH WITH A FORCE 558 00:30:35,733 --> 00:30:37,767 OF PERHAPS 20 HIROSHIMA BOMBS. 559 00:30:37,767 --> 00:30:42,200 IF YOU WATCH THOSE VIDEOS OF THAT METEOR IN RUSSIA 560 00:30:42,200 --> 00:30:45,100 WITH THE INCREDIBLE SONIC BOOM, 561 00:30:45,100 --> 00:30:47,233 YOU COULD SEE HOW EVEN A SMALL OBJECT -- 562 00:30:47,233 --> 00:30:49,167 RELATIVELY SMALL IN A COSMIC SENSE -- 563 00:30:49,167 --> 00:30:51,133 COULD PRODUCE A DRAMATIC EVENT FOR HUMANS. 564 00:30:51,133 --> 00:30:52,900 THE WAY IT WORKS IS 565 00:30:52,900 --> 00:30:54,833 SMALL OBJECTS ARE HITTING THE EARTH EVERY DAY, 566 00:30:54,833 --> 00:30:57,233 LARGE OBJECTS, EVERY WEEK, 567 00:30:57,233 --> 00:30:59,500 LARGER OBJECTS STILL, EVERY YEAR. 568 00:30:59,500 --> 00:31:03,667 Narrator: AND AN OBJECT THE SIZE OF THE CHELYABINSK METEOR 569 00:31:03,667 --> 00:31:07,733 STRIKES, ON AVERAGE, ONCE EVERY CENTURY. 570 00:31:09,800 --> 00:31:11,633 SO WHEN THE NEXT BIG ONE STRIKES -- 571 00:31:11,633 --> 00:31:13,300 NOT IF... 572 00:31:15,300 --> 00:31:16,467 ...WHAT WILL HAPPEN? 573 00:31:16,467 --> 00:31:19,067 [ CREATURES ROARING, SCREECHING ] 574 00:31:19,067 --> 00:31:21,267 THE CLUES LIE IN THE PAST 575 00:31:21,267 --> 00:31:23,633 IN THE EXTINCTION OF THE DINOSAURS. 576 00:31:23,633 --> 00:31:25,733 Thaller: ABOUT 65 MILLION YEARS AGO, 577 00:31:25,733 --> 00:31:27,367 THERE WAS A PERFECT MORNING ON EARTH. 578 00:31:27,367 --> 00:31:28,900 I WOULD'VE LOVED TO HAVE BEEN THERE 579 00:31:28,900 --> 00:31:31,267 TO SEE THE GIANT DINOSAURS, YOU KNOW, 580 00:31:31,267 --> 00:31:34,067 THE PTERODACTYLS FLYING THROUGH THE AIR, ALL OF THAT. 581 00:31:34,067 --> 00:31:35,600 AND THEN SOMETHING CHANGED, 582 00:31:35,600 --> 00:31:37,633 AND THE EARTH WOULD NEVER BE THE SAME. 583 00:31:37,633 --> 00:31:39,367 IF YOU WOULD'VE LOOKED INTO THE SKY, 584 00:31:39,367 --> 00:31:41,467 YOU WOULD'VE SEEN A RELATIVELY DIM LIGHT AT FIRST 585 00:31:41,467 --> 00:31:43,700 COMING TOWARDS YOU, GETTING BRIGHTER AND BRIGHTER, 586 00:31:43,700 --> 00:31:45,767 AND HOTTER AND HOTTER. 587 00:31:45,767 --> 00:31:48,200 Narrator: IT'S A SIX-MILE-WIDE ROCK 588 00:31:48,200 --> 00:31:50,233 THE SIZE OF MOUNT EVEREST 589 00:31:50,233 --> 00:31:55,067 RACING TOWARDS THE EARTH AT 25,000 MILES AN HOUR. 590 00:31:55,067 --> 00:31:56,600 Thaller: THE FIRST WAVE OF DESTRUCTION 591 00:31:56,600 --> 00:31:58,933 WOULD'VE STARTED BEFORE THIS OBJECT EVEN HIT. 592 00:31:58,933 --> 00:32:01,300 THERE WOULD'VE BEEN SHOCK WAVES, HEAT, AND WINDS 593 00:32:01,300 --> 00:32:03,067 GOING ACROSS THE ENTIRE PLANET. 594 00:32:03,067 --> 00:32:05,467 EVERYWHERE THAT WAS UNDER THE PATH OF THIS ASTEROID 595 00:32:05,467 --> 00:32:07,600 WOULD'VE BEEN SEARED, SET ON FIRE. 596 00:32:07,600 --> 00:32:09,333 THE OCEANS WOULD'VE BEEN BOILING UNDERNEATH IT. 597 00:32:12,567 --> 00:32:15,067 Narrator: THE ASTEROID SMASHES INTO THE OCEAN 598 00:32:15,067 --> 00:32:18,133 OFF OF WHAT IS NOW MEXICO'S YUCATAN PENINSULA. 599 00:32:19,900 --> 00:32:23,433 IT STRIKES WITH A FORCE TWO MILLION TIMES GREATER 600 00:32:23,433 --> 00:32:26,967 THAN THE BIGGEST NUCLEAR BOMB EVER DETONATED, 601 00:32:26,967 --> 00:32:30,900 AND BLASTS OUT A CRATER 200 MILES ACROSS. 602 00:32:30,900 --> 00:32:36,900 A SUPER-HEATED SHOCK WAVE ROARS OUT AT TWICE THE SPEED OF SOUND. 603 00:32:36,900 --> 00:32:43,333 500 BILLION TONS OF RED-HOT ROCK SOAR TO THE EDGE OF SPACE. 604 00:32:46,067 --> 00:32:47,967 TWO HOURS AFTER IMPACT, 605 00:32:47,967 --> 00:32:51,233 A 300-FOOT TSUNAMI SMASHES INTO THE COAST 606 00:32:51,233 --> 00:32:53,267 OF WHAT IS NOW THE U.S.A. 607 00:32:53,267 --> 00:32:56,100 REACHING AS FAR AS NORTH CAROLINA. 608 00:33:01,133 --> 00:33:03,233 OVER THE NEXT FEW HOURS AND DAYS, 609 00:33:03,233 --> 00:33:07,600 THE DEBRIS RAINS DOWN, SETTING THE PLANET ABLAZE. 610 00:33:07,600 --> 00:33:10,833 IN THE FOLLOWING WEEKS AND MONTHS, 611 00:33:10,833 --> 00:33:12,533 SMOKE FROM THE FIRES 612 00:33:12,533 --> 00:33:16,767 ADDS TO THE DUST BLASTED INTO THE ATMOSPHERE. 613 00:33:16,767 --> 00:33:19,433 THERE WAS SO MUCH PULVERIZED ROCK, 614 00:33:19,433 --> 00:33:22,167 ALL OF THE BURNING MATERIALS UP INTO THE ATMOSPHERE, 615 00:33:22,167 --> 00:33:23,600 YOU WOULDN'T HAVE BEEN ABLE TO SEE THE SURFACE. 616 00:33:23,600 --> 00:33:26,067 AND ON THE SURFACE, YOU WOULDN'T HAVE BEEN ABLE TO SEE THE SUN, 617 00:33:26,067 --> 00:33:27,533 AND IT WAS LIKE THAT FOR A LONG TIME. 618 00:33:27,533 --> 00:33:30,100 [ DINOSAUR ROARING ] 619 00:33:30,100 --> 00:33:33,167 Narrator: THIS ANCIENT APOCALYPSE 620 00:33:33,167 --> 00:33:36,100 IS A DISASTER FOR THE DINOSAURS... 621 00:33:36,100 --> 00:33:37,667 [ DINOSAURS GROANING ] 622 00:33:37,667 --> 00:33:41,067 ...BUT WITHOUT IT, WE WOULDN'T BE HERE. 623 00:33:41,067 --> 00:33:43,467 Kaku: BACK THEN, DURING THE TIME OF THE DINOSAURS, 624 00:33:43,467 --> 00:33:47,233 OUR ANCESTORS WERE PROBABLY LITTLE, FURRY MAMMALS 625 00:33:47,233 --> 00:33:49,800 THAT WERE AN EVENING SNACK FOR A DINOSAUR. 626 00:33:49,800 --> 00:33:51,600 WHEN THE DINOSAURS GOT WIPED OUT, 627 00:33:51,600 --> 00:33:52,933 THESE SMALL, LITTLE, FURRY MAMMALS 628 00:33:52,933 --> 00:33:54,700 BEGAN TO EXPAND IN SIZE 629 00:33:54,700 --> 00:33:58,067 TO TAKE OVER THE NICHE LEFT OVER BY THE DINOSAURS. 630 00:33:58,067 --> 00:34:01,467 SO, ONE LIFE-FORM REPLACES ANOTHER LIFE-FORM, 631 00:34:01,467 --> 00:34:05,833 IN THIS CONTINUAL PROCESS CALLED SURVIVAL OF THE FITTEST. 632 00:34:05,833 --> 00:34:09,433 WE ARE HERE BECAUSE OUR ANCESTORS 633 00:34:09,433 --> 00:34:10,800 SURVIVED THE EXTINCTION EVENT, 634 00:34:10,800 --> 00:34:12,867 AND, IN FACT, FLOURISHED BECAUSE OF IT. 635 00:34:12,867 --> 00:34:15,600 FROM OUR POINT OF VIEW, 636 00:34:15,600 --> 00:34:18,533 THAT EXTINCTION EVENT WAS A GOOD THING, 637 00:34:18,533 --> 00:34:21,067 BUT WE'RE HERE FOR A BRIEF MOMENT. 638 00:34:21,067 --> 00:34:24,200 AND THERE WILL BE DISASTERS IN THE FUTURE, 639 00:34:24,200 --> 00:34:26,500 AND ONE OF THEM WILL DESTROY US. 640 00:34:26,500 --> 00:34:29,533 Narrator: THERE IS A 1 IN 5,000 CHANCE 641 00:34:29,533 --> 00:34:33,500 THAT AN ASTEROID, THE SAME SIZE AS THE DINOSAUR KILLER, 642 00:34:33,500 --> 00:34:37,067 WILL STRIKE WITHIN THE NEXT 100 YEARS, 643 00:34:37,067 --> 00:34:40,533 AND IT COULD HAPPEN AT ANY TIME. 644 00:34:40,533 --> 00:34:42,100 IT IS A REAL POSSIBILITY 645 00:34:42,100 --> 00:34:44,267 THAT IT COULD HAPPEN IN THE NEXT 10 MINUTES, 646 00:34:44,267 --> 00:34:46,567 BUT IS A TINY POSSIBILITY. 647 00:34:46,567 --> 00:34:48,700 SO, I ALWAYS SAY, "YOU DON'T NEED TO PREPARE VERY MUCH 648 00:34:48,700 --> 00:34:50,167 "FOR WINNING THE LOTTERY, YOU KNOW. 649 00:34:50,167 --> 00:34:52,167 "YOU MAY HAVE A SIMILAR CHANCE TO GETTING TAKEN OUT 650 00:34:52,167 --> 00:34:53,800 BY AN ASTEROID IN THE NEXT 15 MINUTES." 651 00:34:57,467 --> 00:34:59,633 Narrator: APRIL 2014. 652 00:34:59,633 --> 00:35:02,200 SCIENTISTS MAKE A SHOCKING ANNOUNCEMENT -- 653 00:35:02,200 --> 00:35:04,567 SINCE THE YEAR 2000, 654 00:35:04,567 --> 00:35:08,700 26 ASTEROIDS HAVE EXPLODED IN THE EARTH'S ATMOSPHERE, 655 00:35:08,700 --> 00:35:11,967 EACH ONE WITH THE FORCE OF A NUCLEAR BLAST, 656 00:35:11,967 --> 00:35:15,333 WITH SOME UP TO 40 TIMES MORE POWERFUL 657 00:35:15,333 --> 00:35:17,633 THAN THE HIROSHIMA BOMB. 658 00:35:17,633 --> 00:35:21,367 AND WE DIDN'T SPOT A SINGLE ONE OF THEM BEFORE THEY STRUCK. 659 00:35:21,367 --> 00:35:24,367 EVEN IF WE HAD THE TECHNOLOGY 660 00:35:24,367 --> 00:35:26,967 TO DETECT AN ASTEROID BEFORE IT HIT US, 661 00:35:26,967 --> 00:35:29,900 COULD WE DESTROY IT IN TIME? 662 00:35:29,900 --> 00:35:31,700 THE HOLLYWOOD FAVORITE, OF COURSE, IS TO GO OUT THERE 663 00:35:31,700 --> 00:35:33,800 AND NUKE IT, BLOW IT TO SMITHEREENS, RIGHT? 664 00:35:33,800 --> 00:35:36,167 THAT COULD ACTUALLY WORK IN THE CASE OF SOME PARTICULAR, 665 00:35:36,167 --> 00:35:37,900 YOU KNOW, LAST-DITCH EFFORT 666 00:35:37,900 --> 00:35:39,600 FOR ASTEROIDS OF JUST THE RIGHT SIZE. 667 00:35:42,733 --> 00:35:44,433 Narrator: BUT A NUCLEAR BOMB 668 00:35:44,433 --> 00:35:46,667 COULD JUST MAKE A BAD SITUATION WORSE. 669 00:35:50,333 --> 00:35:52,233 TRANSFORMING AN ASTEROID 670 00:35:52,233 --> 00:35:55,067 INTO LARGE RADIOACTIVE CHUNKS 671 00:35:55,067 --> 00:35:57,833 THAT RAIN DOWN ALL OVER THE PLANET. 672 00:36:04,467 --> 00:36:05,867 Durda: BUT THERE ARE ALSO TECHNIQUES, 673 00:36:05,867 --> 00:36:08,800 LIKE SHINING A LASER ON THE ASTEROID OR SUNLIGHT, 674 00:36:08,800 --> 00:36:11,067 WHICH WOULD CREATE AN ARTIFICIAL COMETARY JET, 675 00:36:11,067 --> 00:36:13,333 IF YOU WILL, WOULD VAPORIZE SOME OF THE WATER 676 00:36:13,333 --> 00:36:15,233 AND THE MINERALS ON THE SURFACE OF THAT ASTEROID 677 00:36:15,233 --> 00:36:18,333 TO GENTLY PUSH IT OFF TO THE SIDE. 678 00:36:18,333 --> 00:36:21,167 ANOTHER FANTASTIC TECHNIQUE, A VERY ROBUST ONE, 679 00:36:21,167 --> 00:36:23,533 IS SOMETHING WE CALL THE GRAVITY TRACTOR. 680 00:36:23,533 --> 00:36:25,167 YOU JUST PARK A SPACECRAFT, 681 00:36:25,167 --> 00:36:27,067 THE MASS OF A COMMUNICATION SATELLITE, 682 00:36:27,067 --> 00:36:28,700 NEXT TO THAT SMALL ASTEROID 683 00:36:28,700 --> 00:36:31,400 AND USE THE THRUSTERS ON THE SPACECRAFT 684 00:36:31,400 --> 00:36:34,800 TO KEEP IT HOVERING JUST OFF THE SURFACE OF THE ASTEROID, 685 00:36:34,800 --> 00:36:38,067 AND THAT USES THEN GRAVITY BETWEEN THE TWO AS A TOW LINE 686 00:36:38,067 --> 00:36:40,800 TO MOVE THE ASTEROID EVER SO GENTLY OFF COURSE. 687 00:36:40,800 --> 00:36:42,933 Narrator: RIGHT NOW 688 00:36:42,933 --> 00:36:45,500 THESE TECHNOLOGIES ARE STILL ON THE DRAWING BOARD. 689 00:36:45,500 --> 00:36:48,233 IF THEY DO BECOME A REALITY, 690 00:36:48,233 --> 00:36:51,367 WE'D STILL NEED MONTHS OR YEARS TO PREPARE. 691 00:36:57,333 --> 00:37:00,300 ROGUE PLANETS, ICE AGES, 692 00:37:00,300 --> 00:37:02,333 GAMMA-RAY BURSTS, 693 00:37:02,333 --> 00:37:05,133 VOLCANIC ERUPTIONS, 694 00:37:05,133 --> 00:37:07,567 AND ASTEROID STRIKES. 695 00:37:07,567 --> 00:37:11,067 WE'VE SURVIVED THE WORST THE UNIVERSE CAN THROW AT US, 696 00:37:11,067 --> 00:37:15,333 BUT OUR SPECIES WILL STILL FACE EXTINCTION. 697 00:37:15,333 --> 00:37:19,733 IT'S AS INEVITABLE AS THE SUN RISING. 698 00:37:35,133 --> 00:37:38,500 Narrator: IN A COSMIC BATTLE TO THE DEATH, 699 00:37:38,500 --> 00:37:40,567 WE ARE THE SURVIVORS, 700 00:37:40,567 --> 00:37:44,433 BUT EVENTUALLY THE UNIVERSE WILL WIN 701 00:37:44,433 --> 00:37:47,833 AND WE WILL FACE EXTINCTION... 702 00:37:47,833 --> 00:37:51,300 THREATENED BY THE VERY THING THAT GIVES US LIFE -- 703 00:37:51,300 --> 00:37:54,733 OUR CREATOR, THE SUN. 704 00:37:58,067 --> 00:38:00,900 Oluseyi: WE ORBIT A GIANT NUCLEAR BOMB, THE SUN, 705 00:38:00,900 --> 00:38:02,333 BUT, YOU KNOW, IT'S NOT GOING TO EXPLODE. 706 00:38:02,333 --> 00:38:04,067 IT'S TOO SMALL TO EXPLODE, 707 00:38:04,067 --> 00:38:06,567 BUT WHAT HAPPENS WITH THE SUN IS THAT EVERY DAY, 708 00:38:06,567 --> 00:38:08,267 IT'S A LITTLE BIGGER THAN IT WAS THE DAY BEFORE. 709 00:38:08,267 --> 00:38:11,700 Narrator: SINCE THE SUN'S BIRTH, 710 00:38:11,700 --> 00:38:16,267 HYDROGEN HAS BEEN FUSING INTO HELIUM IN THE SUN'S CORE. 711 00:38:16,267 --> 00:38:20,900 AS THE HELIUM ACCUMULATES, THE CORE GETS DENSER. 712 00:38:20,900 --> 00:38:24,200 WITH 150 MILLION TONS OF HELIUM 713 00:38:24,200 --> 00:38:27,267 SQUEEZING INTO THE CORE EVERY SECOND, 714 00:38:27,267 --> 00:38:30,433 THE GAS COMPRESSES AND HEATS UP. 715 00:38:30,433 --> 00:38:33,867 RIGHT NOW THE TEMPERATURE INSIDE THE SUN'S CORE 716 00:38:33,867 --> 00:38:37,067 IS 27 MILLION DEGREES, 717 00:38:37,067 --> 00:38:39,667 AND ITS GETTING HOTTER ALL THE TIME. 718 00:38:41,333 --> 00:38:43,533 WHAT HAPPENS WHEN YOU HEAT UP A GAS? 719 00:38:43,533 --> 00:38:46,133 IT EXPANDS, AND SO THAT'S WHAT THE SUN IS GOING TO DO. 720 00:38:46,133 --> 00:38:50,933 Narrator: AS THE SUN SWELLS, IT WILL APPEAR BRIGHTER. 721 00:38:50,933 --> 00:38:53,067 Krauss: IN 2 BILLION YEARS, 722 00:38:53,067 --> 00:38:55,733 THE SUN WILL BE ABOUT 15% BRIGHTER 723 00:38:55,733 --> 00:38:57,167 AND THAT WILL LEAD -- 724 00:38:57,167 --> 00:38:59,100 IF THE EARTH REMAINS IN ITS PRESENT ORBIT -- 725 00:38:59,100 --> 00:39:02,067 INEVITABLY TO A RUNAWAY GREENHOUSE EFFECT. 726 00:39:02,067 --> 00:39:03,433 THE OCEANS WILL EVAPORATE, 727 00:39:03,433 --> 00:39:05,433 AND THE SURFACE TEMPERATURE OF THE EARTH 728 00:39:05,433 --> 00:39:07,567 COULD EASILY BE A 1,000 DEGREES. 729 00:39:07,567 --> 00:39:09,067 SO, IF WE DON'T DO ANYTHING, 730 00:39:09,067 --> 00:39:11,067 IN 2 BILLION YEARS, WE'LL BE TOAST. 731 00:39:13,933 --> 00:39:18,100 Narrator: IF WE'RE STILL HERE ON EARTH, WE'LL PERISH. 732 00:39:18,100 --> 00:39:22,533 OTHER TOUGHER SPECIES MAY FIND A WAY TO ADAPT AND SURVIVE, 733 00:39:22,533 --> 00:39:25,533 BUT THEY'LL BE LIVING ON BORROWED TIME. 734 00:39:27,667 --> 00:39:29,133 IT'S GONNA FILL UP THE SKY. 735 00:39:29,133 --> 00:39:31,067 FROM HORIZON TO HORIZON, 736 00:39:31,067 --> 00:39:33,767 THE SKY WILL LITERALLY BE ON FIRE. 737 00:39:33,767 --> 00:39:36,233 Narrator: 5 BILLION YEARS FROM NOW 738 00:39:36,233 --> 00:39:38,400 THE SUN RUNS OUT OF HYDROGEN 739 00:39:38,400 --> 00:39:42,067 AND ENTERS THE FINAL APOCALYPTIC STAGE OF ITS LIFE, 740 00:39:42,067 --> 00:39:45,900 BLOATING TO 100 TIMES ITS CURRENT SIZE. 741 00:39:45,900 --> 00:39:51,067 OUR LIFE-GIVING SUN IS NOW AN ANGRY, RED GIANT. 742 00:39:51,067 --> 00:39:54,067 Thaller: THE RED GIANT STARS ARE SO BIG 743 00:39:54,067 --> 00:39:56,500 THEY WILL ACTUALLY EAT UP THEIR OWN PLANETS. 744 00:39:56,500 --> 00:39:58,567 WE KNOW OF THE EXAMPLES OF RED GIANTS THAT GO 745 00:39:58,567 --> 00:40:00,400 ALL THE WAY OUT TO WHERE THE ORBIT OF JUPITER IS 746 00:40:00,400 --> 00:40:01,900 IN OUR SOLAR SYSTEM. 747 00:40:01,900 --> 00:40:03,567 THE SUN WILL NOT GET QUITE THAT BIG, 748 00:40:03,567 --> 00:40:05,433 BUT IT'LL PROBABLY GET ABOUT OUT TO MARS. 749 00:40:05,433 --> 00:40:07,933 AND EVENTUALLY, IN FACT, THE SUN WILL BE SO LARGE 750 00:40:07,933 --> 00:40:10,800 THAT THE EARTH WILL BE LOCATED INSIDE OF THE SUN, 751 00:40:10,800 --> 00:40:13,733 WHICH CERTAINLY WON'T BE A VERY PLEASANT PLACE TO BE. 752 00:40:13,733 --> 00:40:17,000 Narrator: THE RED GIANT'S BLOATED BODY 753 00:40:17,000 --> 00:40:20,867 ABSORBS THE EARTH, INCINERATING OUR PLANET 754 00:40:20,867 --> 00:40:25,900 UNTIL ITS NOTHING MORE THAN GAS AND DUST INSIDE A DYING STAR. 755 00:40:31,133 --> 00:40:32,600 THE DEATH OF THE SUN 756 00:40:32,600 --> 00:40:36,167 IS THE ULTIMATE MASS-EXTINCTION EVENT. 757 00:40:36,167 --> 00:40:40,433 THERE'S 100% CHANCE IT WILL HAPPEN. 758 00:40:40,433 --> 00:40:45,000 A 100% CHANCE IT WILL DESTROY OUR PLANET 759 00:40:45,000 --> 00:40:47,067 AND ANY LIFE LEFT ON IT. 760 00:40:50,267 --> 00:40:51,833 BUT LIFE ON EARTH MAY NOT BE 761 00:40:51,833 --> 00:40:54,267 THE ONLY LIFE IN THE SOLAR SYSTEM. 762 00:40:56,633 --> 00:40:58,333 AS THE SUN BRIGHTENS, 763 00:40:58,333 --> 00:41:01,267 YOU CAN IMAGINE A WAVE OF HABITABILITY GOING OUT. 764 00:41:01,267 --> 00:41:04,533 SO RIGHT NOW IT'S ON EARTH, IT'LL GO TO MARS, 765 00:41:04,533 --> 00:41:07,233 AND IT'LL GO TO JUPITER, AND ITS MOONS. 766 00:41:07,233 --> 00:41:10,067 Narrator: SCIENTISTS THINK JUPITER'S MOON EUROPA 767 00:41:10,067 --> 00:41:12,200 MAY ALREADY HARBOR ALIEN LIFE 768 00:41:12,200 --> 00:41:16,200 IN A DEEP, LIQUID OCEAN BENEATH ITS FROZEN CRUST. 769 00:41:16,200 --> 00:41:18,533 BUT OUT AT JUPITER, IT'LL BE MUCH WARMER 770 00:41:18,533 --> 00:41:22,200 BUT NOT SO WARM THAT IT WOULD DESTROY EVERYTHING. 771 00:41:22,200 --> 00:41:25,267 SO EVEN WHEN THE EARTH IS GONE, IF THERE'S LIFE ON EUROPA, 772 00:41:25,267 --> 00:41:28,233 IT MAY BE ABLE TO ENDURE THAT. 773 00:41:28,233 --> 00:41:30,800 Narrator: BUT WILL OUR SPECIES GO ON? 774 00:41:30,800 --> 00:41:34,833 CAN WE SURVIVE THE LOSS OF OUR HOME PLANET? 775 00:41:34,833 --> 00:41:36,333 Oluseyi: THE UNIVERSE IS LIKE AN ECOSYSTEM -- 776 00:41:36,333 --> 00:41:38,900 LIVING THINGS ARE GONNA SURVIVE 777 00:41:38,900 --> 00:41:40,800 BASED ON THE LAW OF SURVIVAL OF THE FITTEST. 778 00:41:40,800 --> 00:41:42,433 [ MACHINE WHIRRING ] 779 00:41:42,433 --> 00:41:45,200 WHAT DECIDES IF YOU'RE FIT IN THIS UNIVERSE 780 00:41:45,200 --> 00:41:46,800 IS IF YOU'RE ABLE TO LEAVE YOUR PLANET 781 00:41:46,800 --> 00:41:48,800 AND GO OUT AND POPULATE OTHER PLANETS. 782 00:41:48,800 --> 00:41:52,067 SO THE ONLY SPECIES THAT ARE GONNA LIVE ON FOREVER 783 00:41:52,067 --> 00:41:53,467 ARE THE ONES THAT LEAVE THEIR PLANET. 784 00:41:56,633 --> 00:41:58,900 Narrator: WE CAN'T CONTROL THE UNIVERSE, 785 00:41:58,900 --> 00:42:02,100 BUT WE MAY BE ABLE TO CONTROL OUR FATE. 786 00:42:02,100 --> 00:42:03,733 Krauss: INEVITABLY, IN THE LONG TERM, 787 00:42:03,733 --> 00:42:05,900 THE EARTH IS GONNA BECOME UNINHABITABLE. 788 00:42:05,900 --> 00:42:07,500 IT'S JUST THE WAY THE UNIVERSE WORKS. 789 00:42:07,500 --> 00:42:10,800 IT WASN'T MADE FOR US, IT DOESN'T CARE THAT WE EXIST, 790 00:42:10,800 --> 00:42:13,333 AND IT WON'T CARE WHEN WE GO AWAY. 791 00:42:13,333 --> 00:42:15,833 THE ONLY PEOPLE WHO CARE ABOUT THAT ARE US, 792 00:42:15,833 --> 00:42:17,600 AND WE MIGHT BE ABLE TO DO SOMETHING ABOUT IT. 793 00:42:17,600 --> 00:42:21,233 IN THAT SENSE, WE HAVE A FIGHTING CHANCE. 794 00:42:21,233 --> 00:42:24,700 Narrator: OUR INTELLIGENCE IS OUR GREATEST ASSET. 795 00:42:24,700 --> 00:42:27,200 IT'S THE END RESULT OF FOUR BILLION YEARS 796 00:42:27,200 --> 00:42:29,533 OF EXTINCTION AND EVOLUTION. 797 00:42:29,533 --> 00:42:32,067 AND IT MAY GIVE US A CHANCE TO DO SOMETHING 798 00:42:32,067 --> 00:42:35,433 THAT NO OTHER SPECIES HAS EVER DONE BEFORE -- 799 00:42:35,433 --> 00:42:38,800 BREAK THE CYCLE OF CREATION AND DESTRUCTION 800 00:42:38,800 --> 00:42:40,867 AND LIVE ON. 801 00:42:40,867 --> 00:42:42,433 Thaller: EVERYTHING THAT YOU AND I ARE 802 00:42:42,433 --> 00:42:44,700 IS A CONSEQUENCE OF THE WAY THE UNIVERSE WORKS. 803 00:42:44,700 --> 00:42:47,333 THE UNIVERSE IS VIOLENT, THE UNIVERSE IS DYNAMIC, 804 00:42:47,333 --> 00:42:49,267 IT'S CONSTANTLY PUSHING US TO CHANGE. 805 00:42:49,267 --> 00:42:50,467 AND HERE WE ARE, 806 00:42:50,467 --> 00:42:52,867 THESE INCREDIBLY EVOLVED, INTERESTING CREATURES. 807 00:42:52,867 --> 00:42:55,567 WE'RE A DIRECT CONSEQUENCE OF THE VIOLENCE, 808 00:42:55,567 --> 00:42:57,433 WHICH, IN TURN, WAS OUR CREATION.