1 00:00:06,266 --> 00:00:07,567 This show is fictitious. 2 00:00:07,567 --> 00:00:09,567 There is not actually an asteroid 3 00:00:09,567 --> 00:00:11,300 headed to New York City today, 4 00:00:11,367 --> 00:00:15,467 but this is based on simulations of such an event. 5 00:00:15,567 --> 00:00:18,600 We run simulations of fictional asteroid strike 6 00:00:18,667 --> 00:00:21,600 to prepare for the worst-case scenario. 7 00:00:22,767 --> 00:00:26,266 [Mike Rowe] November 4, 2029. 8 00:00:26,367 --> 00:00:29,100 We face a countdown to catastrophe. 9 00:00:30,567 --> 00:00:33,266 A giant asteroid hurtles towards Earth. 10 00:00:35,567 --> 00:00:36,667 It's heading straight for 11 00:00:36,767 --> 00:00:39,500 the eastern seaboard of the United States. 12 00:00:43,600 --> 00:00:47,967 The space rock could wipe out an entire city 13 00:00:47,967 --> 00:00:50,266 and cause widespread devastation. 14 00:00:53,500 --> 00:00:57,066 Can Earth survive? 15 00:00:59,066 --> 00:01:00,000 [electricity crackles] 16 00:01:00,000 --> 00:01:00,567 [electricity crackles] 17 00:01:01,900 --> 00:01:03,567 [explosion] 18 00:01:12,166 --> 00:01:16,300 New York City, November 4, 2029. 19 00:01:19,166 --> 00:01:23,800 The deserted metropolis waited for the asteroid to strike. 20 00:01:25,066 --> 00:01:27,600 A giant space rock entered the atmosphere, 21 00:01:27,667 --> 00:01:30,000 heading straight for the eastern seaboard of the USA. 22 00:01:30,000 --> 00:01:31,166 heading straight for the eastern seaboard of the USA. 23 00:01:32,667 --> 00:01:34,467 [Plesko] As it comes through the atmosphere, 24 00:01:34,567 --> 00:01:37,667 we would see something as bright as the sun getting 25 00:01:37,667 --> 00:01:39,867 brighter and brighter and brighter. 26 00:01:41,166 --> 00:01:44,367 [Durda] At speeds of maybe 20 kilometers per second or so. 27 00:01:44,367 --> 00:01:46,800 That's something like 18 times faster than 28 00:01:46,867 --> 00:01:50,467 the speed of a bullet coming out of a rifle. 29 00:01:50,567 --> 00:01:53,100 This asteroid was headed towards 30 00:01:53,166 --> 00:01:56,266 the most populous city in America, 31 00:01:56,266 --> 00:01:58,767 and when it impacts, it would deliver 32 00:01:58,867 --> 00:02:00,000 more energy than 1,000 Hiroshima nuclear bombs. 33 00:02:00,000 --> 00:02:03,900 more energy than 1,000 Hiroshima nuclear bombs. 34 00:02:09,967 --> 00:02:11,700 [ explosion ] 35 00:02:14,567 --> 00:02:17,166 It would level some of the most expensive real estate 36 00:02:17,166 --> 00:02:19,000 in the world in seconds. 37 00:02:27,667 --> 00:02:30,000 There would be a crater where Central Park used to be. 38 00:02:30,000 --> 00:02:30,800 There would be a crater where Central Park used to be. 39 00:02:33,667 --> 00:02:36,800 I actually don't even like thinking about this, 40 00:02:36,867 --> 00:02:37,800 [ stammering ] 41 00:02:37,867 --> 00:02:41,266 of how horrible it would be. 42 00:02:41,367 --> 00:02:44,000 [Plait] This is beyond the worst disaster 43 00:02:44,100 --> 00:02:45,700 the world has -- would have ever faced. 44 00:02:45,767 --> 00:02:47,867 There's nothing in our history that would have 45 00:02:47,967 --> 00:02:52,467 done this much damage so quickly and so devastatingly. 46 00:03:01,667 --> 00:03:03,467 [Rowe] The story of the asteroid 47 00:03:03,467 --> 00:03:05,767 and the Earth's fight back 48 00:03:05,767 --> 00:03:08,500 started seven years ago, here in Arizona. 49 00:03:14,467 --> 00:03:16,700 September 2022, 50 00:03:19,000 --> 00:03:21,900 the Catalina Sky Survey. 51 00:03:22,000 --> 00:03:24,700 Guardian of heavens Greg Leonard drives 52 00:03:24,767 --> 00:03:28,100 to Mount Lemmon Observatory near Tucson. 53 00:03:28,166 --> 00:03:30,000 He's on the hunt for asteroids and comets. 54 00:03:30,000 --> 00:03:31,166 He's on the hunt for asteroids and comets. 55 00:03:32,767 --> 00:03:36,700 [Leonard] We are the watchers of the skies for the planet. 56 00:03:36,767 --> 00:03:41,000 We literally represent the first line of defense 57 00:03:41,066 --> 00:03:44,166 against potentially incoming asteroids, 58 00:03:44,266 --> 00:03:48,100 and I want to emphasize the words planetary defense. 59 00:03:48,166 --> 00:03:51,000 This is not in the benefit for one nation. 60 00:03:51,066 --> 00:03:53,867 This is for the entire planet. 61 00:03:53,967 --> 00:03:56,367 [Rowe] Greg takes a series of images 62 00:03:56,467 --> 00:03:59,867 over a 20-minute period. 63 00:03:59,967 --> 00:04:00,000 Stars don't move in the photos, 64 00:04:00,000 --> 00:04:02,567 Stars don't move in the photos, 65 00:04:03,567 --> 00:04:06,066 but asteroids and comets do. 66 00:04:08,166 --> 00:04:10,500 A-ha. 67 00:04:10,567 --> 00:04:12,667 We can see four points of light 68 00:04:12,667 --> 00:04:16,367 tracking across the background of the stationary stars. 69 00:04:16,367 --> 00:04:21,667 This one is moving very quickly across the sky. 70 00:04:21,667 --> 00:04:22,700 So this tells me 71 00:04:22,767 --> 00:04:26,767 this is a real near-Earth asteroid candidate. 72 00:04:29,667 --> 00:04:30,000 [Rowe] It's one of over 27,000 near-Earth asteroids, 73 00:04:30,000 --> 00:04:33,166 [Rowe] It's one of over 27,000 near-Earth asteroids, 74 00:04:33,166 --> 00:04:37,000 or NEAs for short, discovered by the early 2020s. 75 00:04:40,767 --> 00:04:44,100 The huge gravity of Jupiter can rip space rocks 76 00:04:44,166 --> 00:04:47,066 from their home in the asteroid belt. 77 00:04:48,767 --> 00:04:51,767 Some race outwards, away from the sun. 78 00:04:53,600 --> 00:04:58,367 NEAs head inwards, occasionally towards Earth. 79 00:05:00,100 --> 00:05:03,800 We didn't know it back in September of 2022, 80 00:05:03,867 --> 00:05:06,367 but these were our first images 81 00:05:06,367 --> 00:05:08,867 of a deadly incoming asteroid. 82 00:05:10,467 --> 00:05:14,166 [Leonard] It's relatively close to Earth's neighborhood. 83 00:05:14,166 --> 00:05:16,700 We don't know exactly how far it is yet, 84 00:05:16,767 --> 00:05:20,266 but it's close enough where its motion across the sky 85 00:05:20,266 --> 00:05:21,500 appears rapid. 86 00:05:24,367 --> 00:05:26,967 [Rowe] The discovery of an NEA set a series 87 00:05:26,967 --> 00:05:29,667 of planet protection protocols in motion. 88 00:05:32,166 --> 00:05:35,166 Step one, enlist a global team of experts 89 00:05:35,166 --> 00:05:37,300 to investigate the asteroid's orbit. 90 00:05:41,667 --> 00:05:43,367 [Plesko] We have some of the brightest minds, 91 00:05:43,367 --> 00:05:44,567 some of the best telescopes, 92 00:05:44,667 --> 00:05:46,166 some of the biggest supercomputers 93 00:05:46,266 --> 00:05:48,000 working to protect Earth, 94 00:05:48,066 --> 00:05:50,166 collaborating across language barriers, 95 00:05:50,166 --> 00:05:53,166 across international borders to protect humanity. 96 00:05:54,967 --> 00:05:57,467 [Rowe] This international planetary defense team 97 00:05:57,467 --> 00:06:00,000 was tasked with discovering if the distant object 98 00:06:00,000 --> 00:06:01,667 was tasked with discovering if the distant object 99 00:06:01,767 --> 00:06:04,367 would become a serious threat to Earth. 100 00:06:07,400 --> 00:06:08,667 Their first job -- 101 00:06:08,667 --> 00:06:13,000 determine if the NEA's orbit would intersect with our own. 102 00:06:14,667 --> 00:06:16,867 [Plait] Orbits are a little like roads, right? 103 00:06:16,867 --> 00:06:18,867 You've got a path that something follows, 104 00:06:18,967 --> 00:06:21,166 and they can intersect, you can have a crossroads. 105 00:06:21,266 --> 00:06:23,567 Now, typically, if only one object is there, 106 00:06:23,567 --> 00:06:24,867 that's not a big deal, 107 00:06:24,867 --> 00:06:26,667 but if you have two objects approaching that intersection 108 00:06:26,767 --> 00:06:28,767 at the same time, they could collide, 109 00:06:28,867 --> 00:06:30,000 and that's the danger from asteroids. 110 00:06:30,000 --> 00:06:30,767 and that's the danger from asteroids. 111 00:06:34,100 --> 00:06:35,266 [Rowe] The team of scientists 112 00:06:35,367 --> 00:06:37,500 track the asteroid for four months. 113 00:06:39,567 --> 00:06:43,300 [Chodas] Over time, you can build up observations. 114 00:06:43,367 --> 00:06:48,000 You can gradually narrow down the possible number of orbits, 115 00:06:48,066 --> 00:06:53,266 then determine whether there's any chance of a future impact, 116 00:06:53,266 --> 00:06:55,667 but if the asteroid is orbiting the sun, 117 00:06:55,767 --> 00:06:58,767 the Earth is orbiting the sun, and there's this dance going on. 118 00:06:58,767 --> 00:07:00,000 Sometimes the asteroid is near the Earth, 119 00:07:00,000 --> 00:07:01,266 Sometimes the asteroid is near the Earth, 120 00:07:01,367 --> 00:07:03,367 and we can observe it, it's bright. 121 00:07:03,367 --> 00:07:05,266 Other times the asteroid is 122 00:07:05,367 --> 00:07:06,400 on the other side of the sun. 123 00:07:06,467 --> 00:07:07,667 We can't observe it at all. 124 00:07:09,800 --> 00:07:10,900 [Rowe] We were lucky. 125 00:07:11,000 --> 00:07:14,767 The asteroid was visible throughout the fall of 2022. 126 00:07:16,600 --> 00:07:20,300 However, our observations of the space rock's orbit 127 00:07:20,367 --> 00:07:23,100 showed a very real possibility 128 00:07:23,166 --> 00:07:26,400 that it would slam into Earth in just seven years. 129 00:07:30,200 --> 00:07:32,200 [ whooshing ] 130 00:07:32,266 --> 00:07:34,467 Astronomers gave the incoming asteroid 131 00:07:34,567 --> 00:07:37,800 a suitably appropriate name, Apep. 132 00:07:40,000 --> 00:07:43,400 Apep was the Egyptian god of chaos, 133 00:07:43,467 --> 00:07:46,166 so that's a fairly good name for an asteroid 134 00:07:46,166 --> 00:07:47,467 that could hit the Earth 135 00:07:47,467 --> 00:07:49,767 because that's exactly what would happen. 136 00:07:49,867 --> 00:07:52,367 You'd have chaos, destruction, and death. 137 00:08:01,300 --> 00:08:06,266 [Rowe] A catalog of devastation to be unleashed on Earth. 138 00:08:06,266 --> 00:08:09,200 But just how bad would the impact be? 139 00:08:27,000 --> 00:08:29,500 [Rowe] January 2023. 140 00:08:29,567 --> 00:08:32,867 Asteroid Apep was on a collision course with Earth. 141 00:08:34,767 --> 00:08:37,500 Step two in our planetary defense -- 142 00:08:37,567 --> 00:08:41,500 know your enemy and build up a picture of the asteroid. 143 00:08:42,900 --> 00:08:43,125 Apep was 1,800 feet wide, 144 00:08:43,125 --> 00:08:45,100 Apep was 1,800 feet wide, 145 00:08:45,166 --> 00:08:47,500 five times the length of a football field. 146 00:08:48,567 --> 00:08:52,767 Its huge size bumps it up into a new category of asteroids. 147 00:08:54,166 --> 00:08:56,066 Apep was what we refer to as 148 00:08:56,066 --> 00:08:58,900 a PHA, a potentially hazardous asteroid. 149 00:09:01,600 --> 00:09:02,767 We're talking about something 150 00:09:02,867 --> 00:09:04,600 that is a third of a mile across. 151 00:09:04,667 --> 00:09:06,066 This is enormous. 152 00:09:08,800 --> 00:09:13,125 An 1,800-foot-wide asteroid is about 112 million metric tons. 153 00:09:13,125 --> 00:09:13,767 An 1,800-foot-wide asteroid is about 112 million metric tons. 154 00:09:13,767 --> 00:09:17,867 [Rowe] That's over 300 times the weight of the Empire State Building. 155 00:09:21,166 --> 00:09:23,367 Computer simulations of the impact 156 00:09:23,467 --> 00:09:27,767 of an asteroid that massive hitting a city 157 00:09:27,867 --> 00:09:31,567 revealed extraordinary levels of destruction. 158 00:09:32,767 --> 00:09:36,100 An 1,800-foot-diameter asteroid, 159 00:09:36,166 --> 00:09:37,867 that would create a crater 160 00:09:37,967 --> 00:09:42,467 that's 3 or 4 miles across, 1,600 feet deep. 161 00:09:42,567 --> 00:09:43,125 It would have a radiation blast wave that 162 00:09:43,125 --> 00:09:47,100 It would have a radiation blast wave that 163 00:09:47,166 --> 00:09:51,166 would set things on fire for about 20 miles, 164 00:09:51,166 --> 00:09:54,400 but no sooner would things be lit on fire, 165 00:09:54,467 --> 00:09:57,867 there would be a 500-mile-an-hour wind 166 00:09:57,967 --> 00:09:59,467 radiating out, 167 00:09:59,467 --> 00:10:01,900 leveling buildings, knocking down trees, 168 00:10:02,000 --> 00:10:03,967 destroying highways. 169 00:10:03,967 --> 00:10:08,000 100 miles away, you'd still feel a magnitude seven earthquake. 170 00:10:09,400 --> 00:10:12,000 It's not easy to say what is going to kill you first. 171 00:10:12,066 --> 00:10:13,125 It's probably going to be simply the flash of energy. 172 00:10:13,125 --> 00:10:15,300 It's probably going to be simply the flash of energy. 173 00:10:15,367 --> 00:10:18,800 There's so much heat from this thing that you can be vaporized. 174 00:10:18,867 --> 00:10:20,667 If you somehow survived that, 175 00:10:20,767 --> 00:10:22,700 then there's going to be the blast wave that will 176 00:10:22,767 --> 00:10:24,467 pulverize anything in its path. 177 00:10:26,000 --> 00:10:28,000 [Rowe] To build an accurate simulation, 178 00:10:28,066 --> 00:10:32,100 the scientists used more than size and mass. 179 00:10:32,166 --> 00:10:34,900 They also studied its composition 180 00:10:35,000 --> 00:10:36,500 and the speed of its orbit. 181 00:10:38,266 --> 00:10:40,867 [Fast] You need to know what an asteroid is made of, 182 00:10:40,867 --> 00:10:42,867 the speed of that asteroid, 183 00:10:42,867 --> 00:10:43,125 how large it is in order to understand, 184 00:10:43,125 --> 00:10:45,600 how large it is in order to understand, 185 00:10:45,667 --> 00:10:47,767 will it make it through Earth's atmosphere, 186 00:10:47,867 --> 00:10:50,467 and what might the impact effects be? 187 00:10:52,767 --> 00:10:57,667 [Rowe] Asteroids vary in composition and structure. 188 00:10:57,667 --> 00:11:01,567 Some are loose collections of small rocks, 189 00:11:01,567 --> 00:11:06,600 others rocky and compact. 190 00:11:06,667 --> 00:11:09,867 The most dangerous are metallic. 191 00:11:09,867 --> 00:11:12,500 A metal asteroid can be five times as dense 192 00:11:12,567 --> 00:11:13,125 as some of the lower density asteroids, 193 00:11:13,125 --> 00:11:14,667 as some of the lower density asteroids, 194 00:11:14,767 --> 00:11:17,567 and so for the same speeds on the same orbits 195 00:11:17,567 --> 00:11:20,066 they pack way more punch when it comes to an impact. 196 00:11:24,700 --> 00:11:25,767 [Thaller] If you want to see exactly 197 00:11:25,767 --> 00:11:28,266 what a metallic asteroid can do, 198 00:11:28,367 --> 00:11:31,200 go no farther than Barringer Crater in Arizona. 199 00:11:31,266 --> 00:11:34,066 Now that crater is about a mile across, 200 00:11:34,066 --> 00:11:38,667 and the meteor that made it was only about 150 feet across. 201 00:11:38,667 --> 00:11:42,400 [Rowe] Arizona, 50,000 years ago. 202 00:11:42,467 --> 00:11:43,125 The last major asteroid strike on present day North America, 203 00:11:43,125 --> 00:11:46,667 The last major asteroid strike on present day North America, 204 00:11:48,567 --> 00:11:50,867 a tiny metallic space rock 205 00:11:50,867 --> 00:11:54,900 hits the ground at 25,000 miles an hour, 206 00:11:55,000 --> 00:12:00,367 releasing energy equivalent to 2.5 million tons of TNT. 207 00:12:02,500 --> 00:12:06,867 Scale that up to the size of 1,800-foot Apep, 208 00:12:06,967 --> 00:12:10,467 and it would create a blast wave the size of Delaware. 209 00:12:11,467 --> 00:12:13,125 If Apep were a metal asteroid, it would tear through 210 00:12:13,125 --> 00:12:14,300 If Apep were a metal asteroid, it would tear through 211 00:12:14,367 --> 00:12:16,667 the atmosphere like a cosmic bullet. 212 00:12:16,667 --> 00:12:19,200 In a modern city, without warning, 213 00:12:19,266 --> 00:12:21,000 it could kill a lot of people. 214 00:12:23,000 --> 00:12:25,266 But although they're very dangerous, 215 00:12:25,367 --> 00:12:30,467 they're also very rare. 216 00:12:30,567 --> 00:12:34,567 [Rowe] More common are rubble piles, 217 00:12:34,567 --> 00:12:39,066 loose collections of small rocks held together by gravity. 218 00:12:46,667 --> 00:12:49,000 Rubble pile is kind of the perfect name for them, 219 00:12:49,100 --> 00:12:51,200 but you can think of them as like a literally 220 00:12:51,266 --> 00:12:54,767 a pile of stuff out of a dump truck in your driveway, 221 00:12:54,867 --> 00:12:57,266 but if you take that and you put that in space, 222 00:12:57,367 --> 00:12:59,367 they don't have much gravity but they have enough to stay 223 00:12:59,367 --> 00:13:00,667 bound to each other, 224 00:13:00,667 --> 00:13:03,100 and that's your rubble pile asteroid. 225 00:13:03,166 --> 00:13:07,567 They are just barely holding on to themselves. 226 00:13:07,667 --> 00:13:11,166 If you were to come and just apply sufficient gravity, 227 00:13:11,266 --> 00:13:13,125 you could rip it apart. 228 00:13:13,125 --> 00:13:14,567 you could rip it apart. 229 00:13:18,367 --> 00:13:21,166 [Rowe] Pressure and heat from entering our atmosphere 230 00:13:21,266 --> 00:13:24,967 can also tear a rubble pile asteroid to pieces, 231 00:13:28,867 --> 00:13:31,867 but that can be just as dangerous to a city below. 232 00:13:34,700 --> 00:13:36,166 The breakup of an asteroid in 233 00:13:36,166 --> 00:13:38,667 the upper atmosphere is -- is pretty devastating. 234 00:13:38,767 --> 00:13:41,400 It's like a nuclear weapon going off in the atmosphere, 235 00:13:41,467 --> 00:13:43,125 flattening buildings and breaking windows. 236 00:13:43,125 --> 00:13:44,000 flattening buildings and breaking windows. 237 00:13:44,100 --> 00:13:45,567 There are going to be mass casualties 238 00:13:45,667 --> 00:13:46,800 from an event like that 239 00:13:46,867 --> 00:13:49,266 due to just the injuries from flying glass and debris. 240 00:13:54,567 --> 00:13:59,266 [Rowe] To discover what type of asteroid Apep belonged to, 241 00:13:59,367 --> 00:14:01,266 the planetary protection team 242 00:14:01,367 --> 00:14:04,367 train their telescopes onto the space rock. 243 00:14:07,567 --> 00:14:10,367 Analysis revealed that Apep was a rocky, 244 00:14:10,367 --> 00:14:13,125 carbonaceous chondrite asteroid, or C-type for short. 245 00:14:13,125 --> 00:14:14,567 carbonaceous chondrite asteroid, or C-type for short. 246 00:14:17,066 --> 00:14:19,166 C-type asteroids like Apep 247 00:14:19,166 --> 00:14:21,700 are less dense than metal asteroids, 248 00:14:21,767 --> 00:14:24,767 but more solid than rubble piles. 249 00:14:24,867 --> 00:14:27,100 If a big enough C-type asteroid 250 00:14:27,166 --> 00:14:29,266 penetrates the Earth's atmosphere, 251 00:14:29,266 --> 00:14:32,300 it has the chance to make it all the way down to the surface. 252 00:14:32,367 --> 00:14:35,166 It doesn't necessarily burn up in the atmosphere. 253 00:14:43,000 --> 00:14:43,125 [Rowe] Apep's size, mass, and composition told us 254 00:14:43,125 --> 00:14:46,467 [Rowe] Apep's size, mass, and composition told us 255 00:14:46,467 --> 00:14:50,100 it would punch through our atmosphere and hit the surface. 256 00:14:54,100 --> 00:14:57,567 The final piece of information needed to accurately predict 257 00:14:57,667 --> 00:15:00,266 the true amount of damage from the impact 258 00:15:00,367 --> 00:15:04,467 was Apep's kinetic energy, the amount of energy 259 00:15:04,567 --> 00:15:06,867 the asteroid would punch into the ground. 260 00:15:09,166 --> 00:15:13,000 The kinetic energy of an object depends on the mass, 261 00:15:13,066 --> 00:15:13,125 and it depends even more strongly on the speed. 262 00:15:13,125 --> 00:15:16,567 and it depends even more strongly on the speed. 263 00:15:16,567 --> 00:15:19,567 More mass creates more kinetic energy, 264 00:15:19,667 --> 00:15:23,867 but more velocity will increase the kinetic energy by 265 00:15:23,967 --> 00:15:25,467 a squared factor. 266 00:15:25,567 --> 00:15:28,800 For example, if something has twice the velocity, 267 00:15:28,867 --> 00:15:32,166 it will have four times the same energy. 268 00:15:32,266 --> 00:15:36,200 [Rowe] Scientists calculated how much energy Apep, 269 00:15:36,266 --> 00:15:39,667 weighing in at 123 million tons 270 00:15:39,667 --> 00:15:42,200 and traveling at 40,000 miles an hour, 271 00:15:42,266 --> 00:15:43,125 would transfer into the Earth. 272 00:15:43,125 --> 00:15:45,567 would transfer into the Earth. 273 00:15:45,567 --> 00:15:47,600 So what kind of energies were involved here? 274 00:15:47,667 --> 00:15:50,800 Uh, you know, 1,800-foot diameter asteroid. 275 00:15:50,867 --> 00:15:53,000 It's 112 million tons, 276 00:15:53,066 --> 00:15:55,867 and it's traveling at 40,000 miles per hour. 277 00:15:55,967 --> 00:15:57,100 That's something on the order of 278 00:15:57,166 --> 00:15:59,667 10 to the 19th joules of energy, 279 00:15:59,667 --> 00:16:02,266 a one followed by 19 zeros. 280 00:16:10,266 --> 00:16:13,125 1.8 times 10 to the 19 joules is equivalent to 5,000 megatons. 281 00:16:13,125 --> 00:16:16,300 1.8 times 10 to the 19 joules is equivalent to 5,000 megatons. 282 00:16:16,367 --> 00:16:18,000 Take a one megaton nuke, 283 00:16:18,066 --> 00:16:23,367 a substantial nuclear weapon, and then blow up 5,000 of them. 284 00:16:23,367 --> 00:16:27,200 That is roughly the same amount as all the nuclear 285 00:16:27,266 --> 00:16:28,367 weapons on Earth, 286 00:16:28,467 --> 00:16:29,867 detonating all at once. 287 00:16:35,166 --> 00:16:38,000 [Rowe] A strike this large would affect the whole planet. 288 00:16:40,700 --> 00:16:43,000 [Sutter] This would have global impacts. 289 00:16:43,100 --> 00:16:43,125 We would have to deal with the fallout, 290 00:16:43,125 --> 00:16:44,467 We would have to deal with the fallout, 291 00:16:44,567 --> 00:16:47,300 the literal fallout from this event for -- 292 00:16:47,367 --> 00:16:49,166 for potentially 1,000 years. 293 00:16:53,200 --> 00:16:55,567 [Rowe] Spring, 2023. 294 00:16:55,667 --> 00:16:58,166 We had two choices -- 295 00:16:58,166 --> 00:17:02,200 do nothing and face a planet-changing catastrophe, 296 00:17:02,266 --> 00:17:04,700 or fight back. 297 00:17:04,767 --> 00:17:07,166 We chose to take on Apep. 298 00:17:08,667 --> 00:17:11,567 It was the first time in human history 299 00:17:11,567 --> 00:17:13,125 that we might actually be able to prevent a natural disaster 300 00:17:13,125 --> 00:17:15,100 that we might actually be able to prevent a natural disaster 301 00:17:15,166 --> 00:17:16,667 from happening. 302 00:17:16,767 --> 00:17:20,166 We could plan and launch a response mission, 303 00:17:20,166 --> 00:17:21,667 so we don't have to get out of the way. 304 00:17:21,767 --> 00:17:23,900 Make it get out of the way instead. 305 00:17:26,867 --> 00:17:29,700 [Rowe] The mission's objective was simple -- 306 00:17:29,767 --> 00:17:33,467 stop the asteroid, and save the world. 307 00:17:35,767 --> 00:17:38,567 We can't superglue an earthquake fault shut. 308 00:17:38,567 --> 00:17:41,467 We can't cork volcanoes, 309 00:17:41,567 --> 00:17:43,125 but planning for an asteroid impact 310 00:17:43,125 --> 00:17:44,266 but planning for an asteroid impact 311 00:17:44,367 --> 00:17:46,100 is something we really could do. 312 00:17:55,367 --> 00:17:57,600 [Rowe] June 2023. 313 00:17:59,600 --> 00:18:04,667 A large asteroid was headed towards Earth. 314 00:18:04,767 --> 00:18:09,100 It was predicted to strike on November 4, 2029. 315 00:18:16,467 --> 00:18:17,567 To protect our planet, 316 00:18:17,600 --> 00:18:18,500 A team of scientists plan to deflect the asteroid. 317 00:18:18,500 --> 00:18:25,367 A team of scientists plan to deflect the asteroid. 318 00:18:25,467 --> 00:18:27,667 [Sutter] An 1,800-foot wide asteroid 319 00:18:27,767 --> 00:18:29,467 was headed towards the Earth. 320 00:18:29,567 --> 00:18:34,567 We needed it to go in literally any other direction. 321 00:18:34,667 --> 00:18:37,667 [Rowe] So how could we push Apep off course? 322 00:18:39,166 --> 00:18:44,867 Scientists found a clue in the asteroid belt. 323 00:18:47,900 --> 00:18:48,500 Sometimes the lumps of space debris collide 324 00:18:48,500 --> 00:18:51,400 Sometimes the lumps of space debris collide 325 00:18:51,467 --> 00:18:54,567 and change their trajectory. 326 00:18:54,567 --> 00:18:59,700 Maybe we could replicate this and deflect Apep. 327 00:18:59,767 --> 00:19:02,200 We could try to deflect the asteroid and change its orbit 328 00:19:02,266 --> 00:19:04,600 so that it actually misses the Earth. 329 00:19:04,667 --> 00:19:06,400 [Sutter] If you do it early enough, 330 00:19:06,467 --> 00:19:10,400 it may not be much, less than half a millimeter per second, 331 00:19:10,467 --> 00:19:12,967 but that is enough. 332 00:19:12,967 --> 00:19:17,800 These asteroids travel for millions of miles, and so over 333 00:19:17,867 --> 00:19:18,500 the course of days, weeks, 334 00:19:18,500 --> 00:19:19,667 the course of days, weeks, 335 00:19:19,667 --> 00:19:24,000 months, and years, it will have a radically different orbit. 336 00:19:25,066 --> 00:19:26,567 [Rowe] Sounds simple. 337 00:19:26,667 --> 00:19:30,000 Send up a rocket with a robotic space probe, 338 00:19:30,066 --> 00:19:34,567 travel millions of miles, and knock Apep away from Earth. 339 00:19:35,867 --> 00:19:36,767 Piece of cake. 340 00:19:38,867 --> 00:19:39,934 In the movies, 341 00:19:40,000 --> 00:19:42,166 when there's a threatening asteroid that's found, 342 00:19:42,266 --> 00:19:45,967 there's always a rocket on the pad ready to go after that, 343 00:19:45,967 --> 00:19:48,500 and it's not the case in real life. 344 00:19:48,500 --> 00:19:48,767 and it's not the case in real life. 345 00:19:48,867 --> 00:19:51,166 It takes years to design the mission, 346 00:19:51,166 --> 00:19:53,400 to build the satellite, to launch it, 347 00:19:53,467 --> 00:19:54,867 and then it has to get there, 348 00:19:54,867 --> 00:19:57,867 and that might be millions of miles away from Earth. 349 00:19:59,000 --> 00:20:01,367 [Rowe] Fortunately, Earth had a head start. 350 00:20:02,700 --> 00:20:05,000 We detected Apep early, 351 00:20:07,367 --> 00:20:12,066 and we'd already built an asteroid deflector called 352 00:20:12,066 --> 00:20:15,266 the Double Asteroid Redirection Test, 353 00:20:15,266 --> 00:20:17,500 or DART for short. 354 00:20:19,500 --> 00:20:24,100 In 2021 we sent DART 6.8 million miles 355 00:20:24,166 --> 00:20:27,700 to rendezvous with an asteroid called Didymos. 356 00:20:28,867 --> 00:20:31,500 Didymos posed no threat to Earth, 357 00:20:31,567 --> 00:20:33,967 but allowed us to test the technology. 358 00:20:35,467 --> 00:20:36,867 [Thaller] The asteroid called Didymos 359 00:20:36,967 --> 00:20:40,200 has a small moon asteroid going around it. 360 00:20:40,266 --> 00:20:41,300 The point of the DART mission 361 00:20:41,367 --> 00:20:44,200 was to send an impactor into this little moon 362 00:20:44,266 --> 00:20:47,100 and see how much we nudge it off the orbit that it's in. 363 00:20:48,667 --> 00:20:50,967 [Rowe] Lessons learned from DART 364 00:20:50,967 --> 00:20:53,200 would inspire a new mission. 365 00:20:56,066 --> 00:20:58,767 November 2025. 366 00:20:58,767 --> 00:21:01,467 We launched the DAAFE mission -- 367 00:21:01,467 --> 00:21:06,066 deflect Apep away from Earth. 368 00:21:06,066 --> 00:21:09,367 This wasn't a test run to a safe asteroid. 369 00:21:09,467 --> 00:21:12,967 This was the real deal, a mission to save our planet. 370 00:21:12,967 --> 00:21:17,100 It was an enormous technical challenge, 371 00:21:17,166 --> 00:21:18,500 and we had no idea if it would work. 372 00:21:18,500 --> 00:21:20,000 and we had no idea if it would work. 373 00:21:21,200 --> 00:21:25,000 When you think about a spacecraft going from Earth 374 00:21:25,066 --> 00:21:28,100 millions of miles away to hit an asteroid 375 00:21:28,166 --> 00:21:29,767 at an exact point in time, 376 00:21:29,767 --> 00:21:30,967 at an exact point in space. 377 00:21:30,967 --> 00:21:33,367 It's really the ultimate bullseye. 378 00:21:33,367 --> 00:21:37,100 It's like trying to hit one bullet with another bullet 379 00:21:37,166 --> 00:21:39,367 launched from the other side of a continent. 380 00:21:41,667 --> 00:21:43,667 [Rowe] November 2028. 381 00:21:44,767 --> 00:21:48,500 After three years in space, DAAFE arrived at Apep. 382 00:21:48,500 --> 00:21:50,000 After three years in space, DAAFE arrived at Apep. 383 00:21:52,467 --> 00:21:54,367 This was our last chance. 384 00:21:54,367 --> 00:21:56,000 This was our only chance. 385 00:21:59,266 --> 00:22:00,266 [Rowe] The kinetic impactor 386 00:22:00,266 --> 00:22:04,166 smashed into Apep at 14,000 miles an hour. 387 00:22:10,800 --> 00:22:14,200 On Earth, telescopes and radar tracked the collision. 388 00:22:15,800 --> 00:22:16,967 Did it work? 389 00:22:16,967 --> 00:22:18,500 Did we push the asteroid off course? 390 00:22:18,500 --> 00:22:20,467 Did we push the asteroid off course? 391 00:22:20,567 --> 00:22:22,467 At first glance, the mission worked. 392 00:22:22,567 --> 00:22:25,767 We deflected Apep away from us. 393 00:22:28,000 --> 00:22:29,667 [Rowe] It looked like the mission worked. 394 00:22:32,800 --> 00:22:34,667 [Plait] As an astronomer, and, you know, 395 00:22:34,667 --> 00:22:36,867 a human who has to live on this planet, 396 00:22:36,967 --> 00:22:38,300 I was very happy, right? 397 00:22:38,367 --> 00:22:41,000 We've just literally saved the world. 398 00:22:41,066 --> 00:22:43,667 [Rowe] But the happiness was short-lived. 399 00:22:44,767 --> 00:22:46,000 There was a problem. 400 00:22:46,100 --> 00:22:48,500 The collision had pushed Apep away from Earth, 401 00:22:48,500 --> 00:22:49,767 The collision had pushed Apep away from Earth, 402 00:22:53,266 --> 00:22:57,667 but it also sheared off a 300-foot chunk of rock. 403 00:22:59,367 --> 00:23:03,400 This smaller asteroid, called Apep 2.0, 404 00:23:03,467 --> 00:23:05,166 could still be a significant threat. 405 00:23:08,266 --> 00:23:13,100 A 300-foot chunk of rock is still very, very large. 406 00:23:13,166 --> 00:23:14,667 300 feet wide. 407 00:23:14,767 --> 00:23:17,000 That's almost a football field. 408 00:23:18,100 --> 00:23:18,500 [Plesko] So the important things we needed to know -- 409 00:23:18,500 --> 00:23:19,967 [Plesko] So the important things we needed to know -- 410 00:23:19,967 --> 00:23:21,567 was it going to hit us? 411 00:23:22,600 --> 00:23:24,800 And if so, where is it going to hit us? 412 00:23:26,900 --> 00:23:31,066 [Rowe] March 2029, we got our answer. 413 00:23:31,066 --> 00:23:33,266 Its point of impact -- 414 00:23:33,367 --> 00:23:36,000 The east coast of the United States, 415 00:23:37,600 --> 00:23:40,767 with New York City in the firing line. 416 00:23:43,500 --> 00:23:46,066 SUTTER: A smaller chunk headed for New York City. 417 00:23:47,200 --> 00:23:48,500 This was the worst-case scenario. 418 00:23:48,500 --> 00:23:50,066 This was the worst-case scenario. 419 00:23:59,000 --> 00:24:00,166 I want to emphasize, 420 00:24:00,166 --> 00:24:02,467 there's no asteroid headed toward New York tonight. 421 00:24:02,467 --> 00:24:05,367 This is just a discussion about 422 00:24:05,467 --> 00:24:07,367 what this process would be like. 423 00:24:15,567 --> 00:24:16,867 [Rowe] In 2028, 424 00:24:16,867 --> 00:24:19,900 we tried to deflect Apep away from Earth. 425 00:24:22,166 --> 00:24:23,999 The mission wasn't a complete success. 426 00:24:23,999 --> 00:24:26,767 The mission wasn't a complete success. 427 00:24:26,867 --> 00:24:28,767 Yes, we managed to actually divert 428 00:24:28,767 --> 00:24:31,500 the large asteroid away from hitting the Earth, 429 00:24:31,567 --> 00:24:34,367 but in doing so, we broke off a clump big enough 430 00:24:34,467 --> 00:24:37,300 to be very dangerous heading toward the eastern seaboard. 431 00:24:39,667 --> 00:24:44,300 [Rowe] June 2029, five months to impact. 432 00:24:46,367 --> 00:24:48,867 The future looked bleak for New York, 433 00:24:48,967 --> 00:24:50,767 but it wasn't the time to give up. 434 00:24:52,000 --> 00:24:53,667 They reassessed an idea 435 00:24:53,667 --> 00:24:53,999 first suggested to destroy the original 1,800-foot Apep, 436 00:24:53,999 --> 00:25:00,066 first suggested to destroy the original 1,800-foot Apep, 437 00:25:00,066 --> 00:25:01,467 a nuclear strike. 438 00:25:03,800 --> 00:25:05,266 It worked in Armageddon. 439 00:25:05,266 --> 00:25:07,266 Maybe it would work in real life. 440 00:25:08,600 --> 00:25:12,266 However, studies revealed that nuking an asteroid 441 00:25:12,367 --> 00:25:16,467 wasn't as simple as it looks in a Hollywood movie. 442 00:25:16,467 --> 00:25:17,467 Hey, let's blow it up. 443 00:25:17,567 --> 00:25:18,667 Let's nuke it, right? 444 00:25:18,667 --> 00:25:20,667 Well, instead of one big problem, 445 00:25:20,667 --> 00:25:22,500 now you have slightly smaller problems, 446 00:25:22,567 --> 00:25:23,999 and they're radioactive, by the way. 447 00:25:23,999 --> 00:25:24,900 and they're radioactive, by the way. 448 00:25:25,000 --> 00:25:26,166 So you don't want to do that. 449 00:25:28,000 --> 00:25:30,500 [Rowe] Computer simulations revealed 450 00:25:30,567 --> 00:25:32,166 that even the world's largest 451 00:25:32,166 --> 00:25:36,367 nuclear weapon had only 1 percent of the energy needed 452 00:25:36,367 --> 00:25:40,266 to destroy the original 1,800-foot Apep. 453 00:25:42,166 --> 00:25:46,100 We needed the world's most powerful nuclear weapon 454 00:25:46,166 --> 00:25:50,700 and 99 of its best friends, launch them all simultaneously, 455 00:25:50,767 --> 00:25:53,999 and have them simultaneously hit the asteroid. 456 00:25:53,999 --> 00:25:54,200 and have them simultaneously hit the asteroid. 457 00:25:54,266 --> 00:25:57,600 It was simply beyond our technological capabilities. 458 00:26:00,300 --> 00:26:02,467 [Rowe] Fortunately, thanks to the DAAFE mission, 459 00:26:02,467 --> 00:26:06,567 we only had to take out the 300-foot Apep 2.0. 460 00:26:12,100 --> 00:26:15,166 Could we blow the smaller asteroid out of the sky? 461 00:26:19,100 --> 00:26:22,667 Maybe, but launching a nuclear Hail Mary 462 00:26:22,767 --> 00:26:23,999 would be very controversial. 463 00:26:23,999 --> 00:26:24,500 would be very controversial. 464 00:26:26,500 --> 00:26:31,166 Nuclear devices are the most powerful, 465 00:26:31,166 --> 00:26:32,867 really, one of the most emotional 466 00:26:32,867 --> 00:26:35,900 things that humans have ever invented. 467 00:26:39,767 --> 00:26:43,300 [Rivkin] They are the most powerful tool in our toolbox. 468 00:26:43,367 --> 00:26:46,367 We've got a hammer, and it's a very big hammer, 469 00:26:46,467 --> 00:26:49,767 but there are a lot of concerns with them, 470 00:26:49,867 --> 00:26:53,266 so they cannot be tested in space, 471 00:26:53,367 --> 00:26:53,999 according to international law. 472 00:26:53,999 --> 00:26:55,000 according to international law. 473 00:26:56,567 --> 00:26:59,767 [Rowe] Without being able to test nukes in space, 474 00:26:59,867 --> 00:27:01,667 they were considered too big a risk, 475 00:27:06,100 --> 00:27:10,166 but New York had one final potential savior, 476 00:27:11,400 --> 00:27:13,166 the Earth itself. 477 00:27:16,900 --> 00:27:20,000 2013, Chelyabinsk, Russia. 478 00:27:21,600 --> 00:27:23,999 An asteroid blew up in the atmosphere. 479 00:27:23,999 --> 00:27:24,266 An asteroid blew up in the atmosphere. 480 00:27:26,600 --> 00:27:28,767 It didn't make it all the way to the surface, 481 00:27:28,767 --> 00:27:31,467 and the people in Chelyabinsk are very lucky because of that. 482 00:27:33,100 --> 00:27:36,100 [Rowe] The 60-foot-wide Chelyabinsk asteroid 483 00:27:36,166 --> 00:27:38,166 was rocky like Apep, 484 00:27:39,000 --> 00:27:41,000 and it moved at a similar velocity, 485 00:27:41,100 --> 00:27:43,000 around 40,000 miles an hour, 486 00:27:44,867 --> 00:27:50,600 but it met its match when it entered Earth's atmosphere. 487 00:27:50,667 --> 00:27:52,667 Earth's atmosphere doesn't look like much. 488 00:27:52,767 --> 00:27:53,999 You think, oh, it's just air, it doesn't matter, 489 00:27:53,999 --> 00:27:54,667 You think, oh, it's just air, it doesn't matter, 490 00:27:54,767 --> 00:27:57,367 but all of those molecules actually exert pressure 491 00:27:57,367 --> 00:27:58,867 on the front edge of the asteroid, 492 00:27:58,967 --> 00:28:02,266 slowing it down and heating it up. 493 00:28:02,266 --> 00:28:03,367 Rock heated up 494 00:28:03,467 --> 00:28:07,767 and began to crumble and explode as it came through. 495 00:28:07,867 --> 00:28:10,567 [Rowe] The midair explosion, called an airburst, 496 00:28:10,567 --> 00:28:15,166 released more energy than 440,000 tons of TNT. 497 00:28:21,500 --> 00:28:23,767 The shockwave traveled 100 miles, 498 00:28:24,800 --> 00:28:27,300 damaging 7,000 buildings 499 00:28:27,367 --> 00:28:29,266 and injuring 1,500 people. 500 00:28:30,700 --> 00:28:33,200 But a ground strike hitting a city 501 00:28:33,266 --> 00:28:34,467 would have been a lot worse. 502 00:28:42,300 --> 00:28:46,500 Apep 2.0 was five times larger than the Chelyabinsk Rock. 503 00:28:48,700 --> 00:28:50,367 Would it break up during its 504 00:28:50,467 --> 00:28:53,867 10-second trip down through the atmosphere, 505 00:28:53,967 --> 00:28:53,999 or would it pierce right through? 506 00:28:53,999 --> 00:28:58,367 or would it pierce right through? 507 00:28:58,467 --> 00:29:01,500 The planetary defense team ran simulations. 508 00:29:03,667 --> 00:29:07,000 As that comes through Earth's atmosphere, 509 00:29:07,100 --> 00:29:10,000 some of that hot air can get into the cracks. 510 00:29:11,066 --> 00:29:14,467 [Rowe] Friction and pressure would heat Apep 2.0's 511 00:29:14,567 --> 00:29:17,867 surface to thousands of degrees Fahrenheit. 512 00:29:19,100 --> 00:29:22,000 At those temperatures, even rock burns. 513 00:29:23,300 --> 00:29:23,999 We would see this flaming monster 514 00:29:23,999 --> 00:29:26,467 We would see this flaming monster 515 00:29:26,567 --> 00:29:30,767 of death coming racing through our atmosphere. 516 00:29:30,767 --> 00:29:34,166 There are gonna be pieces of debris vaporizing 517 00:29:34,266 --> 00:29:35,567 and coming off of it. 518 00:29:35,567 --> 00:29:37,667 So you get these flashes of light that happen 519 00:29:37,767 --> 00:29:39,367 one after another -- pop, pop, pop, pop, pop, pop, pop, 520 00:29:39,367 --> 00:29:40,900 as these things are blowing up. 521 00:29:46,667 --> 00:29:48,066 [Rowe] The computer simulations 522 00:29:48,066 --> 00:29:50,000 showed that the extra bulk of 523 00:29:50,100 --> 00:29:53,767 Apep 2.0 would stop it from blowing up. 524 00:29:57,100 --> 00:29:59,800 Some of the asteroid would blast away, 525 00:29:59,867 --> 00:30:01,900 but most of the space rock 526 00:30:02,000 --> 00:30:05,600 would reach the Earth's surface. 527 00:30:05,667 --> 00:30:07,800 So that close to the actual impact, 528 00:30:07,867 --> 00:30:10,200 we pretty much just had to hunker down and take it. 529 00:30:13,567 --> 00:30:16,400 [Rowe] The prospects for New York City were grim. 530 00:30:18,100 --> 00:30:20,300 It was facing annihilation. 531 00:30:32,667 --> 00:30:35,166 [Rowe] October 2029. 532 00:30:35,266 --> 00:30:39,367 Three weeks to impact. 533 00:30:39,467 --> 00:30:42,800 For the citizens of the New York metropolitan area, 534 00:30:42,867 --> 00:30:47,867 there was only one goal -- Get out of the firing line. 535 00:30:52,567 --> 00:30:53,567 Now we had to have 536 00:30:53,600 --> 00:30:56,024 the plans in place to evacuate these cities. 537 00:30:56,024 --> 00:30:57,000 the plans in place to evacuate these cities. 538 00:30:57,100 --> 00:31:01,500 It was a major emergency for New York and its citizens. 539 00:31:01,567 --> 00:31:04,200 Time to move out of the way. 540 00:31:05,567 --> 00:31:08,467 [Rowe] To work out who should evacuate and to where, 541 00:31:08,567 --> 00:31:10,600 Scientists ran detailed projections 542 00:31:10,667 --> 00:31:14,400 of the potential blast area. 543 00:31:14,467 --> 00:31:17,467 There's an ellipse there that we call the hazard ellipse that 544 00:31:17,567 --> 00:31:21,600 says somewhere in this area is where the asteroid will hit. 545 00:31:21,667 --> 00:31:23,467 That means there's a little wiggle room 546 00:31:23,567 --> 00:31:26,024 and a range of areas that are in danger. 547 00:31:26,024 --> 00:31:26,100 and a range of areas that are in danger. 548 00:31:28,066 --> 00:31:31,166 [Rowe] Based on the hazard ellipse projections, 549 00:31:31,266 --> 00:31:34,100 the government issued evacuation orders 550 00:31:34,166 --> 00:31:36,767 for the tri-state area, 551 00:31:36,867 --> 00:31:39,567 and as far south as Philadelphia. 552 00:31:39,567 --> 00:31:43,667 It was the biggest evacuation in US history. 553 00:31:43,667 --> 00:31:46,567 Millions were displaced. 554 00:31:46,667 --> 00:31:49,066 It was physically horrific. 555 00:31:51,300 --> 00:31:54,266 I live in the New York metropolitan area. 556 00:31:54,266 --> 00:31:56,024 It was horrible for me and my family and my friends, 557 00:31:56,024 --> 00:31:57,266 It was horrible for me and my family and my friends, 558 00:31:57,266 --> 00:32:01,800 but we can't just sit here and cross our fingers and hope that 559 00:32:01,867 --> 00:32:03,300 we don't get struck. 560 00:32:04,867 --> 00:32:07,367 [Rowe] The freeways out of the city were jammed. 561 00:32:11,767 --> 00:32:14,000 Trains were packed. 562 00:32:14,100 --> 00:32:16,867 Over 23 million people evacuated, 563 00:32:17,967 --> 00:32:20,567 leaving behind a deserted city. 564 00:32:23,166 --> 00:32:25,767 Computer models show that the epicenter 565 00:32:25,767 --> 00:32:26,024 of the strike would be Manhattan. 566 00:32:26,024 --> 00:32:27,800 of the strike would be Manhattan. 567 00:32:31,000 --> 00:32:35,200 The blast would reduce the city to rubble and ash. 568 00:32:36,266 --> 00:32:39,300 There would be a one-mile-wide crater resulting from it, 569 00:32:39,367 --> 00:32:41,367 so deep that it would actually take 570 00:32:41,467 --> 00:32:44,767 the entire subway system and turn it upside down and lay it 571 00:32:44,867 --> 00:32:47,700 onto the rim of the crater. 572 00:32:47,767 --> 00:32:50,166 You would have a magnitude 5 earthquake 573 00:32:50,166 --> 00:32:52,266 at even six miles away from that, 574 00:32:52,367 --> 00:32:54,467 and there would be a big air blast, 575 00:32:54,467 --> 00:32:56,024 400-mile-an-hour winds. 576 00:32:56,024 --> 00:32:56,367 400-mile-an-hour winds. 577 00:32:57,800 --> 00:33:00,400 Something as light as a pencil could be a lethal weapon 578 00:33:00,467 --> 00:33:02,266 when picked up by a shock wave like that. 579 00:33:03,800 --> 00:33:07,767 As the crater is blasting out and excavating itself, 580 00:33:07,867 --> 00:33:13,467 there would be little blobs of molten rock that get thrown out 581 00:33:13,567 --> 00:33:16,300 in this wave, going faster than the speed of sound, 582 00:33:18,266 --> 00:33:19,700 Like drops a fiery rain, 583 00:33:19,767 --> 00:33:22,667 if you will, landing back miles away from the crater. 584 00:33:27,767 --> 00:33:29,800 [Rowe] The city would be on fire. 585 00:33:32,266 --> 00:33:35,567 So, um, there's just no upside to this. 586 00:33:35,667 --> 00:33:36,567 There's nothing good. 587 00:33:36,600 --> 00:33:38,900 It's just all from bad to horrific. 588 00:33:40,900 --> 00:33:43,567 [Rowe] But New York is by the ocean. 589 00:33:43,567 --> 00:33:48,266 What would happen if Apep 2.0 hit the sea? 590 00:33:52,567 --> 00:33:56,000 Detailed simulations have revealed two very 591 00:33:56,066 --> 00:33:57,166 different outcomes 592 00:33:57,166 --> 00:34:00,867 for an asteroid hitting the ocean at high speeds. 593 00:34:04,400 --> 00:34:07,467 SUTTER: If a giant asteroid strikes the deep ocean, 594 00:34:07,567 --> 00:34:09,600 less than 1 percent of its energy 595 00:34:09,667 --> 00:34:11,467 gets converted into waves. 596 00:34:11,467 --> 00:34:13,767 Those waves quickly disperse. 597 00:34:13,867 --> 00:34:16,567 They quickly lose energy as they travel. 598 00:34:16,567 --> 00:34:20,467 By the time they reach the coast, it might just be 599 00:34:20,467 --> 00:34:21,467 a little ripple, 600 00:34:21,567 --> 00:34:23,500 you might not even be able to surf on it. 601 00:34:29,667 --> 00:34:32,467 [Rowe] If the asteroid hit shallow coastal waters, 602 00:34:34,867 --> 00:34:37,700 it could cause significant damage along the shoreline. 603 00:34:39,467 --> 00:34:43,300 If an asteroid, the size of Apep hits the continental shelf 604 00:34:43,367 --> 00:34:45,367 where the water is relatively shallow, 605 00:34:45,367 --> 00:34:48,467 then it could potentially cause a tsunami. 606 00:34:52,700 --> 00:34:54,867 [Rowe] But that would just be the start of the problems. 607 00:34:58,200 --> 00:34:59,867 With a shallow water impactor, 608 00:34:59,867 --> 00:35:03,200 huge amounts of steam are generated basically by 609 00:35:03,266 --> 00:35:06,667 the energy of that impactor vaporizing all the water. 610 00:35:06,667 --> 00:35:08,967 Well, all the water is then put up into the atmosphere, 611 00:35:08,967 --> 00:35:12,266 and water is a really good greenhouse gas. 612 00:35:12,367 --> 00:35:14,166 So you have warming from the launch of water 613 00:35:14,166 --> 00:35:15,200 up into the atmosphere. 614 00:35:15,266 --> 00:35:17,867 You have cooling from all of the ash and dust. 615 00:35:24,266 --> 00:35:25,266 [Rowe] A short bout of warming 616 00:35:25,367 --> 00:35:26,024 would be followed by a brutal winter. 617 00:35:26,024 --> 00:35:27,667 would be followed by a brutal winter. 618 00:35:29,166 --> 00:35:31,800 Crops would fail. 619 00:35:31,867 --> 00:35:37,800 This impact has so many horrible follow-on consequences. 620 00:35:37,867 --> 00:35:40,767 That tells us how difficult it would be to -- 621 00:35:40,867 --> 00:35:43,667 to rebuild from an event like this. 622 00:35:47,600 --> 00:35:48,667 [Rowe] The eastern seaboard 623 00:35:48,667 --> 00:35:52,066 would suffer a serious economic downturn. 624 00:35:52,066 --> 00:35:54,166 It would take decades to recover. 625 00:35:59,200 --> 00:36:01,100 November 3rd, 2029. 626 00:36:02,500 --> 00:36:04,567 One day until impact. 627 00:36:06,400 --> 00:36:09,667 The space rock was just 400,000 miles away, 628 00:36:10,667 --> 00:36:16,000 and traveling 13 times faster than an F-15 fighter jet. 629 00:36:16,100 --> 00:36:20,367 It was first a dim star, and then a brighter star, 630 00:36:20,467 --> 00:36:23,166 and then in the hours before, you can actually see it 631 00:36:23,266 --> 00:36:24,367 approaching the Earth. 632 00:36:25,867 --> 00:36:26,024 [Rowe] New York looked outmatched. 633 00:36:26,024 --> 00:36:28,700 [Rowe] New York looked outmatched. 634 00:36:28,767 --> 00:36:31,700 It looked like Apep would win, 635 00:36:31,767 --> 00:36:34,600 but this was not the end of the game. 636 00:36:34,667 --> 00:36:37,467 Earth had one final card to play. 637 00:36:49,467 --> 00:36:51,567 [Rowe] November 4th, 2029. 638 00:36:53,500 --> 00:36:57,300 The 300-foot Apep 2.0 reached Earth. 639 00:36:59,800 --> 00:37:01,367 The space rock pierced our 640 00:37:01,367 --> 00:37:05,166 atmosphere and hurtled towards the surface. 641 00:37:18,100 --> 00:37:22,000 Then the asteroid passed over Manhattan, 642 00:37:24,367 --> 00:37:27,066 over Brooklyn, 643 00:37:27,066 --> 00:37:28,767 and over Coney Island. 644 00:37:31,100 --> 00:37:35,400 It hit deep ocean, 350 miles off the coast. 645 00:37:42,200 --> 00:37:45,767 Apep 2.0 missed New York. 646 00:37:45,767 --> 00:37:46,667 But how? 647 00:37:50,300 --> 00:37:52,200 Our 7-year battle with the asteroid 648 00:37:52,266 --> 00:37:55,166 resolved in a matter of seconds 649 00:37:55,166 --> 00:37:58,200 thanks to orbital dynamics. 650 00:37:59,300 --> 00:38:01,567 The orbit of the asteroid and the orbit of the Earth 651 00:38:01,667 --> 00:38:05,400 and the way the Earth spins in this great cosmic ballet 652 00:38:05,467 --> 00:38:06,700 means that 653 00:38:06,767 --> 00:38:10,266 a few seconds earlier or later makes the difference between 654 00:38:10,266 --> 00:38:11,699 hitting the ocean and hitting land. 655 00:38:11,699 --> 00:38:12,400 hitting the ocean and hitting land. 656 00:38:13,800 --> 00:38:16,266 [Rowe] Earth rotates at 1,000 miles an hour 657 00:38:17,700 --> 00:38:22,567 and orbits the sun at close to 65,000 miles an hour. 658 00:38:22,567 --> 00:38:26,700 Apep orbited at 40,000 miles an hour, 659 00:38:26,767 --> 00:38:31,467 but Apep 2.0 traveled fractionally slower. 660 00:38:33,266 --> 00:38:36,166 The impact of the DAAFE mission that sheared off 661 00:38:36,266 --> 00:38:41,367 the 300-foot chunk of rock had also slowed it down. 662 00:38:41,467 --> 00:38:41,699 Slowing down Apep 663 00:38:41,699 --> 00:38:42,867 Slowing down Apep 664 00:38:42,967 --> 00:38:45,166 changed when it's going to intersect the Earth. 665 00:38:45,266 --> 00:38:47,100 So New York spun out of the crosshairs. 666 00:38:51,700 --> 00:38:56,066 [Rowe] Apep 2.0, hit the ocean and exploded, 667 00:38:56,066 --> 00:38:57,667 breaking up instantly. 668 00:39:00,100 --> 00:39:03,467 The strike threw up a wall of water into the air, 669 00:39:03,467 --> 00:39:05,667 followed by huge clouds of steam. 670 00:39:07,500 --> 00:39:11,000 The impact created small surface waves that quickly 671 00:39:11,066 --> 00:39:11,699 died away. 672 00:39:11,699 --> 00:39:12,200 died away. 673 00:39:13,600 --> 00:39:17,700 It's like doing a gigantic interplanetary belly flop. 674 00:39:17,767 --> 00:39:20,767 It evaporates, it obliterates, and it generates 675 00:39:20,767 --> 00:39:23,500 an enormous amount of steam, and it sets up shock waves. 676 00:39:23,567 --> 00:39:25,266 All that energy is still released, 677 00:39:25,367 --> 00:39:28,467 but the ocean is capable of absorbing it. 678 00:39:31,767 --> 00:39:35,600 [Rowe] New York dodged the bullet and escaped unscathed 679 00:39:37,266 --> 00:39:40,400 thanks to the dedication, ingenuity, 680 00:39:40,467 --> 00:39:41,699 and enterprise of a global team of scientists. 681 00:39:41,699 --> 00:39:48,200 and enterprise of a global team of scientists. 682 00:39:50,500 --> 00:39:54,667 Apep was an imaginary asteroid, 683 00:39:54,767 --> 00:39:58,700 but there are many potentially hazardous space rocks out there. 684 00:40:01,467 --> 00:40:04,266 Thankfully, this was a fictional scenario. 685 00:40:04,367 --> 00:40:07,867 It's a thought exercise, but it's informed by our real, 686 00:40:07,967 --> 00:40:11,000 actual knowledge we've gained over the years of dealing with, 687 00:40:11,066 --> 00:40:11,699 you know, potential close approaches and the hazard from 688 00:40:11,699 --> 00:40:13,900 you know, potential close approaches and the hazard from 689 00:40:14,000 --> 00:40:18,266 real asteroids that we actually know about. 690 00:40:18,266 --> 00:40:21,867 Asteroid research is a good insurance policy 691 00:40:21,967 --> 00:40:23,567 for our species. 692 00:40:23,567 --> 00:40:27,066 Hopefully we will never need to carry these things out 693 00:40:27,066 --> 00:40:28,567 for real. 694 00:40:28,567 --> 00:40:30,867 [Rowe] Large asteroid strikes are rare, 695 00:40:32,300 --> 00:40:34,066 but we cannot be complacent. 696 00:40:39,266 --> 00:40:41,699 The most important thing to do in planetary defense 697 00:40:41,699 --> 00:40:42,667 The most important thing to do in planetary defense 698 00:40:42,767 --> 00:40:44,400 is to find them early. 699 00:40:44,467 --> 00:40:46,767 If we find them early, we have a chance to predict 700 00:40:46,767 --> 00:40:49,600 the possible impacts and we have a chance to mitigate them. 701 00:40:54,767 --> 00:40:56,600 [Rowe] Our technology is improving, 702 00:40:58,066 --> 00:41:01,400 so we can detect incoming space rocks earlier, 703 00:41:03,667 --> 00:41:06,200 but we need to be vigilant, 704 00:41:06,266 --> 00:41:10,767 because the threat from asteroids is not going away. 705 00:41:12,066 --> 00:41:13,567 Apart from climate change, 706 00:41:13,567 --> 00:41:17,166 asteroid strikes are, in my opinion, the most dangerous 707 00:41:17,166 --> 00:41:18,567 thing to life on Earth. 708 00:41:19,867 --> 00:41:21,767 [Plait] A lot of the times the question I get is, 709 00:41:21,867 --> 00:41:23,767 "What are the chances of this happening?" 710 00:41:23,867 --> 00:41:26,567 And they don't like the answer because I say 100 percent. 711 00:41:28,700 --> 00:41:29,867 It takes time. 712 00:41:29,900 --> 00:41:33,000 It may not be for a week, a month, a year, a century. 713 00:41:33,066 --> 00:41:35,467 But studying these asteroids informs us on 714 00:41:35,567 --> 00:41:37,400 what we can do to prevent an impact. 715 00:41:39,000 --> 00:41:41,266 There are a lot of natural disasters that we can do 716 00:41:41,266 --> 00:41:41,699 nothing about -- earthquakes, hurricanes, 717 00:41:41,699 --> 00:41:43,400 nothing about -- earthquakes, hurricanes, 718 00:41:43,467 --> 00:41:44,367 that sort of thing. 719 00:41:44,367 --> 00:41:46,567 Here is something way more devastating 720 00:41:46,667 --> 00:41:50,400 than any of those, and we can prevent them. 721 00:41:50,467 --> 00:41:52,600 So we have to keep our eyes on 722 00:41:52,667 --> 00:41:54,767 the prize and our eyes on the skies.