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These are the user uploaded subtitles that are being translated: 1 00:00:00,868 --> 00:00:06,071 ? 2 00:00:06,073 --> 00:00:07,039 Narrator: Aliens... 3 00:00:07,041 --> 00:00:08,040 Little green men. 4 00:00:08,042 --> 00:00:11,110 A thousand eyes or one-eyed. 5 00:00:11,112 --> 00:00:13,746 Narrator: ...Sci-fi movie monsters. 6 00:00:13,748 --> 00:00:15,114 Free-floating with tentacles. 7 00:00:15,116 --> 00:00:19,151 Some unknown hyper-advanced civilization. 8 00:00:19,153 --> 00:00:23,355 Narrator: Could science fiction ever become fact? 9 00:00:23,357 --> 00:00:25,124 I think it's really simple why Hollywood 10 00:00:25,126 --> 00:00:28,527 is fascinated with the concept of first contact with aliens, 11 00:00:28,529 --> 00:00:30,763 because that would be probably the greatest 12 00:00:30,765 --> 00:00:33,599 scientific discovery in all of human history. 13 00:00:36,037 --> 00:00:39,438 Narrator: Problem is, our universe creates massive barriers 14 00:00:39,440 --> 00:00:41,774 to meeting extraterrestrials. 15 00:00:41,776 --> 00:00:45,377 It's almost as if the universe is deliberately 16 00:00:45,379 --> 00:00:48,547 stopping us from making first contact. 17 00:00:48,549 --> 00:00:50,482 Narrator: We're searching the cosmos. 18 00:00:50,484 --> 00:00:54,353 Will we ever find intelligent alien life? 19 00:00:54,355 --> 00:00:56,622 Or are we alone? 20 00:00:56,624 --> 00:00:59,625 -- Captions by vitac -- www.vitac.com 21 00:00:59,627 --> 00:01:02,694 captions paid for by discovery communications 22 00:01:02,696 --> 00:01:05,731 [ explosion ] 23 00:01:11,005 --> 00:01:14,073 ? 24 00:01:14,075 --> 00:01:19,011 Arecibo observatory, Puerto Rico. 25 00:01:19,013 --> 00:01:22,881 45 years ago, it sent a powerful radio message 26 00:01:22,883 --> 00:01:25,751 deep into space, 27 00:01:25,753 --> 00:01:30,789 kickstarting our efforts to make first contact. 28 00:01:30,791 --> 00:01:34,560 Pacini: The arecibo message was the first communication 29 00:01:34,562 --> 00:01:37,963 or attempt to communicate with a possible civilization 30 00:01:37,965 --> 00:01:42,201 out there in the galaxy or outside of our galaxy. 31 00:01:42,203 --> 00:01:44,736 Narrator: Today, that message is speeding towards 32 00:01:44,738 --> 00:01:47,206 the m13 galaxy cluster 33 00:01:47,208 --> 00:01:51,276 25,000 light-years away. 34 00:01:51,278 --> 00:01:55,581 It contains information about our world -- 35 00:01:55,583 --> 00:01:57,149 where we are, 36 00:01:57,151 --> 00:02:00,719 even the makeup of our DNA. 37 00:02:00,721 --> 00:02:03,188 Pacini: The purpose of this message was, of course, 38 00:02:03,190 --> 00:02:04,790 like, trying to say hi, 39 00:02:04,792 --> 00:02:08,026 and also, like, to light up this question about, 40 00:02:08,028 --> 00:02:10,028 are we alone in the universe? 41 00:02:14,068 --> 00:02:15,934 Narrator: But what chances are there 42 00:02:15,936 --> 00:02:19,238 that an intelligent alien race is out there 43 00:02:19,240 --> 00:02:21,507 waiting to receive our message? 44 00:02:23,444 --> 00:02:25,410 Do I think there's other intelligent life 45 00:02:25,412 --> 00:02:26,612 out there in the universe? 46 00:02:26,614 --> 00:02:28,747 The answer is a resounding yes. Yes, I do. 47 00:02:28,749 --> 00:02:30,482 We know that life began on earth 48 00:02:30,484 --> 00:02:32,584 pretty much as soon as our planet solidified. 49 00:02:32,586 --> 00:02:35,120 So why wouldn't that have happened somewhere else? 50 00:02:36,690 --> 00:02:39,558 Narrator: If life has evolved on other worlds, 51 00:02:39,560 --> 00:02:42,227 just how many alien civilizations 52 00:02:42,229 --> 00:02:46,999 are out there that we could potentially contact? 53 00:02:47,001 --> 00:02:49,868 Astronomer frank Drake developed an equation 54 00:02:49,870 --> 00:02:53,238 to help answer this crucial question. 55 00:02:53,240 --> 00:02:56,508 The Drake equation is a really admirable attempt 56 00:02:56,510 --> 00:02:59,144 to apply some quantitative reasoning 57 00:02:59,146 --> 00:03:01,813 to the probability, or the possibility, 58 00:03:01,815 --> 00:03:04,650 that there is life beyond the earth. 59 00:03:04,652 --> 00:03:07,886 Freese: You multiply the star formation rate 60 00:03:07,888 --> 00:03:09,321 for stars in our galaxy 61 00:03:09,323 --> 00:03:13,025 times the number of planets that each star has 62 00:03:13,027 --> 00:03:14,359 times the probability 63 00:03:14,361 --> 00:03:17,696 that you would have life forming on that planet 64 00:03:17,698 --> 00:03:22,167 times the probability that that life form becomes intelligent. 65 00:03:22,169 --> 00:03:24,469 And they estimated that there were about 66 00:03:24,471 --> 00:03:28,774 10,000 intelligent civilizations within our galaxy. 67 00:03:28,776 --> 00:03:33,879 ? 68 00:03:33,881 --> 00:03:36,782 Narrator: Since the Drake equation was first proposed, 69 00:03:36,784 --> 00:03:41,587 our understanding of the galaxy has radically transformed. 70 00:03:41,589 --> 00:03:46,625 We have now discovered worlds outside our solar system -- 71 00:03:46,627 --> 00:03:49,461 exoplanets. 72 00:03:49,463 --> 00:03:52,297 Filippenko: Exoplanets are being discovered all over the place. 73 00:03:52,299 --> 00:03:55,100 There are about 4,000 of them now known, 74 00:03:55,102 --> 00:03:58,437 and techniques are finding more every day. 75 00:04:00,441 --> 00:04:02,407 Narrator: Scientists believe what we've found 76 00:04:02,409 --> 00:04:04,176 is the tip of the iceberg. 77 00:04:06,981 --> 00:04:10,449 So if the cosmos is so good at making planets, 78 00:04:10,451 --> 00:04:12,618 perhaps it can produce the conditions 79 00:04:12,620 --> 00:04:16,321 to make life throughout the universe. 80 00:04:16,323 --> 00:04:19,458 When the Drake equation was devised all those decades ago, 81 00:04:19,460 --> 00:04:22,394 we didn't know that exoplanets existed. 82 00:04:22,396 --> 00:04:25,530 And now we think that there are quite literally more planets 83 00:04:25,532 --> 00:04:28,634 than there are stars in the universe. 84 00:04:28,636 --> 00:04:30,669 So even if life is really rare, 85 00:04:30,671 --> 00:04:32,871 there are an enormous number of chances 86 00:04:32,873 --> 00:04:35,240 for it to take hold in the universe. 87 00:04:35,242 --> 00:04:37,242 And for this reason, it is very likely that 88 00:04:37,244 --> 00:04:39,645 there is life relatively abundant in the universe, 89 00:04:39,647 --> 00:04:43,515 including an uncountable number of advanced alien civilizations. 90 00:04:43,517 --> 00:04:44,916 This isn't science fiction. 91 00:04:44,918 --> 00:04:46,818 It's just basic probability. 92 00:04:48,956 --> 00:04:50,622 Narrator: Probability suggests 93 00:04:50,624 --> 00:04:54,026 a multitude of alien civilizations are out there. 94 00:04:54,028 --> 00:04:58,363 So isn't it a little strange we haven't made first contact? 95 00:05:00,000 --> 00:05:01,700 Thaller: I think there's every reason to believe 96 00:05:01,702 --> 00:05:03,702 that there are civilizations out there, 97 00:05:03,704 --> 00:05:05,771 but we have no evidence of them yet. 98 00:05:05,773 --> 00:05:10,075 Why haven't we found other civilizations out there? 99 00:05:10,077 --> 00:05:11,510 Narrator: One answer could be 100 00:05:11,512 --> 00:05:15,414 the sheer vastness of the cosmos. 101 00:05:15,416 --> 00:05:16,782 Bullock: Look at all these lights out here 102 00:05:16,784 --> 00:05:18,283 over the cityscape. 103 00:05:18,285 --> 00:05:21,486 You could think of these lights as, like, stars in the galaxy. 104 00:05:21,488 --> 00:05:24,289 Now, if there's 10,000 communicating civilizations 105 00:05:24,291 --> 00:05:27,426 out there in the galaxy, you might think, "oh, man, look. 106 00:05:27,428 --> 00:05:29,928 There's one right there right down the street." 107 00:05:29,930 --> 00:05:31,330 The problem is 108 00:05:31,332 --> 00:05:33,799 there are hundreds of billions of stars in the galaxy, 109 00:05:33,801 --> 00:05:35,934 which means that maybe our nearest neighbor 110 00:05:35,936 --> 00:05:38,170 that we can communicate with is not right there 111 00:05:38,172 --> 00:05:40,138 but way across the city. 112 00:05:43,444 --> 00:05:46,011 Narrator: We live in the suburbs of the milky way 113 00:05:46,013 --> 00:05:49,681 75,000 light-years from the furthest edge. 114 00:05:51,719 --> 00:05:54,586 Radio signals travel at the speed of light. 115 00:05:58,292 --> 00:06:01,426 This speed limit means that any signal sent 116 00:06:01,428 --> 00:06:03,595 to the opposite side of the galaxy 117 00:06:03,597 --> 00:06:09,234 would take 75,000 years to reach its destination. 118 00:06:09,236 --> 00:06:10,268 Bullock: The thing you have to remember 119 00:06:10,270 --> 00:06:12,237 is the galaxy is gigantic. 120 00:06:12,239 --> 00:06:15,140 Even if there are 10,000 civilizations in the galaxy, 121 00:06:15,142 --> 00:06:18,910 it's possible that the distances between stars are just so huge 122 00:06:18,912 --> 00:06:22,180 that we're never gonna be able communicate with each other. 123 00:06:22,182 --> 00:06:25,817 Narrator: So the 45-year-old arecibo radio message 124 00:06:25,819 --> 00:06:28,820 could still be tens of thousands of years away 125 00:06:28,822 --> 00:06:32,491 from any potential alien civilization. 126 00:06:32,493 --> 00:06:35,560 The target was 25,000 light-years from here. 127 00:06:35,562 --> 00:06:38,597 The message is now 45 light-years from here 128 00:06:38,599 --> 00:06:40,665 'cause it's traveling the speed of light, 129 00:06:40,667 --> 00:06:43,335 so it's really far from the target. 130 00:06:44,838 --> 00:06:48,440 Narrator: The vast size of the universe is a huge roadblock 131 00:06:48,442 --> 00:06:51,943 to making first contact, and the laws of physics 132 00:06:51,945 --> 00:06:55,480 prevent radio signals from overcoming it. 133 00:06:55,482 --> 00:06:58,150 You just cannot go faster than the speed of light. 134 00:06:58,152 --> 00:07:01,987 So our galaxy may be filled with life, filled with civilizations, 135 00:07:01,989 --> 00:07:04,723 but they're so far away. 136 00:07:04,725 --> 00:07:07,292 Tremblay: I don't want to be the bearer of bad news. 137 00:07:07,294 --> 00:07:12,831 But the universe is just really, really far too large. 138 00:07:12,833 --> 00:07:15,033 Narrator: The universe may be large, 139 00:07:15,035 --> 00:07:17,769 but we're putting the most advanced technology on earth 140 00:07:17,771 --> 00:07:21,740 into action to try and speed up the search. 141 00:07:21,742 --> 00:07:25,143 There really is a serious, scientifically valid way 142 00:07:25,145 --> 00:07:27,279 to go looking for other civilizations. 143 00:07:27,281 --> 00:07:28,914 And the breakthrough listen project is really 144 00:07:28,916 --> 00:07:30,715 the best thing we have right now. 145 00:07:30,717 --> 00:07:32,951 State-of-the-art facilities around the world -- 146 00:07:32,953 --> 00:07:35,554 radio telescopes, optical telescopes, as well -- 147 00:07:35,556 --> 00:07:38,290 are all looking up to the sky together. 148 00:07:38,292 --> 00:07:42,027 Narrator: Breakthrough listen is targeting the 1 million stars 149 00:07:42,029 --> 00:07:45,430 and 100 galaxies closest to earth. 150 00:07:45,432 --> 00:07:47,732 It is the most comprehensive search 151 00:07:47,734 --> 00:07:51,269 for alien communications ever undertaken. 152 00:07:53,907 --> 00:07:56,875 If there was an aircraft giving off a radar signal, 153 00:07:56,877 --> 00:08:00,879 and that aircraft was around any of the 1,000 nearest stars, 154 00:08:00,881 --> 00:08:03,048 the breakthrough listen project could hear that. 155 00:08:03,050 --> 00:08:04,382 So if there's something out there 156 00:08:04,384 --> 00:08:06,017 that's actually giving off a signal, 157 00:08:06,019 --> 00:08:09,054 breakthrough listen has a chance to find it. 158 00:08:09,056 --> 00:08:11,056 Narrator: Breakthrough has started by listening in 159 00:08:11,058 --> 00:08:15,727 on the nearest 1,700 stars to earth. 160 00:08:15,729 --> 00:08:16,761 So far? 161 00:08:16,763 --> 00:08:18,296 Silence. 162 00:08:18,298 --> 00:08:19,731 Thaller: This is the wonderfully, 163 00:08:19,733 --> 00:08:21,967 beautifully frustrating position that we find ourselves in. 164 00:08:21,969 --> 00:08:23,702 We haven't heard anything yet. 165 00:08:23,704 --> 00:08:26,004 So we're in this position where a negative result 166 00:08:26,006 --> 00:08:27,572 doesn't mean there aren't civilizations, 167 00:08:27,574 --> 00:08:30,876 but we have no proof that there are. 168 00:08:30,878 --> 00:08:35,213 Narrator: Breakthrough listen is just beginning its hunt. 169 00:08:35,215 --> 00:08:37,282 There's much more real estate in the cosmos 170 00:08:37,284 --> 00:08:38,717 for it to search. 171 00:08:38,719 --> 00:08:43,154 It's a big job, demanding a lot of Patience. 172 00:08:43,156 --> 00:08:44,422 Plait: If you go through Drake's equation 173 00:08:44,424 --> 00:08:45,624 and find this number 174 00:08:45,626 --> 00:08:48,693 of 10,000 intelligent civilizations out there, 175 00:08:48,695 --> 00:08:53,765 there are something like 250 billion stars in the galaxy, 176 00:08:53,767 --> 00:08:59,304 so that's only 1 civilization per 25 million stars. 177 00:08:59,306 --> 00:09:02,440 That's a lot of cold calling. 178 00:09:02,442 --> 00:09:03,742 Narrator: The size of our universe 179 00:09:03,744 --> 00:09:07,445 means we could be waiting a very long time 180 00:09:07,447 --> 00:09:09,881 to pick up any alien communication. 181 00:09:13,921 --> 00:09:16,655 But even if we pick up a signal, 182 00:09:16,657 --> 00:09:19,724 it may have arrived too late. 183 00:09:19,726 --> 00:09:21,159 Oluseyi: If we do receive a message, 184 00:09:21,161 --> 00:09:23,261 given that it probably took years to get here, 185 00:09:23,263 --> 00:09:25,864 that civilization could be long gone. 186 00:09:25,866 --> 00:09:28,433 Narrator: So are we simply too late? 187 00:09:28,435 --> 00:09:32,837 Have any aliens out there already died out? 188 00:09:41,014 --> 00:09:43,048 [ Explosion ] 189 00:09:47,254 --> 00:09:49,020 Narrator: Earth has orbited the sun 190 00:09:49,022 --> 00:09:53,892 for over 4.5 billion years, 191 00:09:53,894 --> 00:09:57,529 time enough for humankind to evolve into an intelligent 192 00:09:57,531 --> 00:09:59,931 and technologically advanced species. 193 00:10:02,402 --> 00:10:04,736 But compared to the age of the universe, 194 00:10:04,738 --> 00:10:08,340 planet earth is just a kid. 195 00:10:08,342 --> 00:10:10,308 Plait: The earth is over 4 1/2 billion years old, 196 00:10:10,310 --> 00:10:11,943 and we think it's taken this long 197 00:10:11,945 --> 00:10:14,613 to create the first technological civilization -- 198 00:10:14,615 --> 00:10:16,181 us. 199 00:10:16,183 --> 00:10:18,783 There are star systems out there much older than we are. 200 00:10:18,785 --> 00:10:22,721 The universe is 13.8 billion years old. 201 00:10:22,723 --> 00:10:25,423 Carroll: We tend to think we're hot stuff, right? 202 00:10:25,425 --> 00:10:27,592 We're technologically capable, we can build rockets, 203 00:10:27,594 --> 00:10:29,427 and we can listen to radio waves. 204 00:10:29,429 --> 00:10:33,732 But a typical other intelligent advanced civilization 205 00:10:33,734 --> 00:10:36,401 would be literally millions of years ahead of us 206 00:10:36,403 --> 00:10:38,036 in technology. 207 00:10:42,042 --> 00:10:46,277 Narrator: So if an alien society has been around longer than us, 208 00:10:46,279 --> 00:10:50,281 how much more technologically advanced could they be? 209 00:10:50,283 --> 00:10:52,751 One method of measuring just how much 210 00:10:52,753 --> 00:10:55,220 is provided by the kardashev scale. 211 00:10:55,222 --> 00:10:57,389 Tremblay: The kardashev scale classifies 212 00:10:57,391 --> 00:11:00,025 potential alien civilizations into three types 213 00:11:00,027 --> 00:11:02,227 based on the amount of energy that they're able to harness 214 00:11:02,229 --> 00:11:03,828 from their local environment. 215 00:11:03,830 --> 00:11:05,730 A type-one civilization can harness the energy 216 00:11:05,732 --> 00:11:07,465 of only its home planet. 217 00:11:07,467 --> 00:11:09,434 Type-two could hypothetically harness the energy 218 00:11:09,436 --> 00:11:10,869 of its own solar system. 219 00:11:10,871 --> 00:11:13,071 And a type-three could harness the energy 220 00:11:13,073 --> 00:11:16,708 potentially of an entire galaxy. 221 00:11:16,710 --> 00:11:19,477 Narrator: If you're wondering where we fit on that scale, 222 00:11:19,479 --> 00:11:22,614 prepare for some bad news. 223 00:11:22,616 --> 00:11:24,949 We are somewhere between zero and a one. 224 00:11:24,951 --> 00:11:27,852 We can't use all of earth's resources. 225 00:11:27,854 --> 00:11:30,655 So we're at about a 0.7. 226 00:11:30,657 --> 00:11:34,059 Narrator: An advanced species reaching kardashev level two 227 00:11:34,061 --> 00:11:35,493 or even three 228 00:11:35,495 --> 00:11:38,463 could create highly advanced structures 229 00:11:38,465 --> 00:11:42,200 that can harness the power of a star. 230 00:11:42,202 --> 00:11:45,070 Plait: If you get to be an advanced enough civilization, 231 00:11:45,072 --> 00:11:48,306 eventually if your energy demands are so huge, 232 00:11:48,308 --> 00:11:49,674 you might build solar panels 233 00:11:49,676 --> 00:11:52,444 that you have enveloped your star. 234 00:11:52,446 --> 00:11:55,013 This was first thought of by Freeman Dyson, 235 00:11:55,015 --> 00:11:57,148 and so we call these Dyson spheres. 236 00:12:00,087 --> 00:12:02,454 Narrator: If such epic engineering occurs 237 00:12:02,456 --> 00:12:06,524 in other star systems or even other galaxies, 238 00:12:06,526 --> 00:12:08,393 could we pick up some evidence 239 00:12:08,395 --> 00:12:12,297 and then make first contact? 240 00:12:12,299 --> 00:12:13,998 Plait: The thing about a Dyson sphere is that 241 00:12:14,000 --> 00:12:15,500 you've completely blocked 242 00:12:15,502 --> 00:12:18,269 all the light coming out from a star, 243 00:12:18,271 --> 00:12:20,438 except for the infrared 244 00:12:20,440 --> 00:12:22,674 because these panels are absorbing that sunlight 245 00:12:22,676 --> 00:12:23,908 and warming up. 246 00:12:23,910 --> 00:12:25,210 When you warm up an object, 247 00:12:25,212 --> 00:12:28,246 it gives off what's called thermal infrared light. 248 00:12:28,248 --> 00:12:30,949 You can scan the skies looking for that signature 249 00:12:30,951 --> 00:12:35,086 to see if there are any Dyson spheres out there. 250 00:12:35,088 --> 00:12:38,356 Narrator: 2015 -- 251 00:12:38,358 --> 00:12:41,659 NASA's wide field infrared survey explorer 252 00:12:41,661 --> 00:12:44,829 scanned 100,000 nearby galaxies 253 00:12:44,831 --> 00:12:48,800 to locate advanced kardashev civilizations 254 00:12:48,802 --> 00:12:54,739 by observing infrared light leaking away from Dyson spheres. 255 00:12:54,741 --> 00:12:56,541 They detected... 256 00:12:56,543 --> 00:12:57,709 Nothing. 257 00:12:57,711 --> 00:13:00,044 Filippenko: No such galaxy was found, 258 00:13:00,046 --> 00:13:03,314 so they didn't find any infrared smoking gun. 259 00:13:03,316 --> 00:13:05,517 Narrator: Given our universe is so old, 260 00:13:05,519 --> 00:13:09,854 surely other civilizations should have had time to evolve. 261 00:13:09,856 --> 00:13:13,491 If so, maybe we've simply missed them. 262 00:13:13,493 --> 00:13:16,628 Plait: It's entirely possible that civilizations arose, 263 00:13:16,630 --> 00:13:19,063 tried to communicate with the galaxy around them, 264 00:13:19,065 --> 00:13:22,233 and the problem was they were asking too early for us. 265 00:13:22,235 --> 00:13:23,468 They're trying to knock on our door, 266 00:13:23,470 --> 00:13:26,905 but our house wasn't built yet. 267 00:13:26,907 --> 00:13:29,507 Narrator: Earth has been around for under one-third 268 00:13:29,509 --> 00:13:34,212 of the universe's 13.8-billion-year lifespan, 269 00:13:34,214 --> 00:13:38,349 the human race just 300,000 years, 270 00:13:38,351 --> 00:13:41,653 a relatively tiny window of opportunity 271 00:13:41,655 --> 00:13:43,555 to make first contact. 272 00:13:43,557 --> 00:13:46,391 We've been looking at the sky for tens of years, 273 00:13:46,393 --> 00:13:47,659 something like that. 274 00:13:47,661 --> 00:13:50,061 What is the likelihood that at that exact moment 275 00:13:50,063 --> 00:13:54,199 someone is gonna be beaming a signal toward us? 276 00:13:54,201 --> 00:13:56,434 Narrator: Perhaps the universe prevents 277 00:13:56,436 --> 00:14:01,372 intelligent civilizations from surviving for very long, 278 00:14:01,374 --> 00:14:04,442 making our chances for first contact 279 00:14:04,444 --> 00:14:06,544 even more unlikely. 280 00:14:06,546 --> 00:14:07,779 Plait: Maybe there is something out there 281 00:14:07,781 --> 00:14:10,782 that is filtering us from seeing them. 282 00:14:10,784 --> 00:14:12,750 We actually call this the great filter. 283 00:14:12,752 --> 00:14:14,018 Maybe there is something that says, 284 00:14:14,020 --> 00:14:16,187 "yeah, you're not getting past here." 285 00:14:16,189 --> 00:14:19,958 Narrator: Rocky planets like ours are ideal for hosting life, 286 00:14:19,960 --> 00:14:22,927 but they're fragile. 287 00:14:22,929 --> 00:14:25,997 And this fragility means the universe 288 00:14:25,999 --> 00:14:29,234 could filter out intelligent life quickly. 289 00:14:29,236 --> 00:14:34,305 ? 290 00:14:34,307 --> 00:14:37,008 We've discovered very violent star explosions 291 00:14:37,010 --> 00:14:39,210 like gamma-ray bursts. 292 00:14:39,212 --> 00:14:41,880 These are powerful enough, they may sterilize planets 293 00:14:41,882 --> 00:14:43,982 even across an entire galaxy. 294 00:14:47,654 --> 00:14:49,654 Narrator: And even if intelligent species 295 00:14:49,656 --> 00:14:52,090 survive natural phenomenon, 296 00:14:52,092 --> 00:14:54,792 they may still be filtered out 297 00:14:54,794 --> 00:14:58,363 by hitting the self-destruct button. 298 00:14:58,365 --> 00:15:00,698 Loeb: As we can tell from our own experience, 299 00:15:00,700 --> 00:15:03,735 the moment that we started developing technology, 300 00:15:03,737 --> 00:15:06,738 we also developed the means for our own destruction 301 00:15:06,740 --> 00:15:09,273 by changing the climate on our planet, 302 00:15:09,275 --> 00:15:11,943 by developing weapons of mass destruction. 303 00:15:11,945 --> 00:15:13,912 And so it's quite possible that civilizations 304 00:15:13,914 --> 00:15:17,081 that are advanced enough are short-lived. 305 00:15:17,083 --> 00:15:18,816 And if they're short-lived, 306 00:15:18,818 --> 00:15:21,152 that would explain why, at this point in time, 307 00:15:21,154 --> 00:15:23,721 there are very few of them that might be around 308 00:15:23,723 --> 00:15:25,523 to communicate with us. 309 00:15:27,761 --> 00:15:31,829 Narrator: Finding the relics of an extinct alien civilization 310 00:15:31,831 --> 00:15:36,167 could be the ultimate cosmic warning for the human race. 311 00:15:36,169 --> 00:15:38,236 Stricker: If we were to find a civilization out there 312 00:15:38,238 --> 00:15:40,805 that may have destroyed themselves by pollution 313 00:15:40,807 --> 00:15:42,140 or conflict, 314 00:15:42,142 --> 00:15:45,643 it would be almost like staring into a mirror, 315 00:15:45,645 --> 00:15:48,112 and it would be a very grim foreshadowing 316 00:15:48,114 --> 00:15:52,183 and maybe a lessons-learned for us humans here on earth. 317 00:15:52,185 --> 00:15:55,687 Narrator: We can only hope that some advanced alien species 318 00:15:55,689 --> 00:15:58,389 escaped the universe's deadly filter. 319 00:16:01,795 --> 00:16:04,696 But even if e.T.S still exist out there, 320 00:16:04,698 --> 00:16:08,333 the odds are still stacked against first contact. 321 00:16:08,335 --> 00:16:13,504 ? 322 00:16:13,506 --> 00:16:17,642 One other way that we've got this alien-contact story 323 00:16:17,644 --> 00:16:22,313 a bit wrong is just down to the laws of physics. 324 00:16:22,315 --> 00:16:25,583 Narrator: Every day, the physics of the cosmos 325 00:16:25,585 --> 00:16:28,252 makes our chances of contact worse 326 00:16:28,254 --> 00:16:31,356 because our universe is expanding, 327 00:16:31,358 --> 00:16:34,492 and it's expanding fast. 328 00:16:41,401 --> 00:16:44,302 [ Explosion ] 329 00:16:46,006 --> 00:16:49,407 ? 330 00:16:49,409 --> 00:16:52,377 Narrator: February 2018 -- 331 00:16:52,379 --> 00:16:55,480 astrophysicists at the university of Oklahoma 332 00:16:55,482 --> 00:16:58,683 find a potential series of rogue planets 333 00:16:58,685 --> 00:17:01,519 3.8 billion light-years away. 334 00:17:04,124 --> 00:17:08,092 Ranging between the size of our moon and Jupiter, 335 00:17:08,094 --> 00:17:10,795 these would be the first alien worlds 336 00:17:10,797 --> 00:17:13,398 ever discovered outside our galaxy... 337 00:17:16,436 --> 00:17:19,837 ...and maybe the first of many. 338 00:17:19,839 --> 00:17:22,673 Our galaxy alone has trillions of planets. 339 00:17:22,675 --> 00:17:25,476 The observable universe has trillions of galaxies -- 340 00:17:25,478 --> 00:17:27,445 it's estimated about 2 trillion. 341 00:17:27,447 --> 00:17:30,381 So trillions of trillions? 342 00:17:30,383 --> 00:17:33,051 Come on. 343 00:17:33,053 --> 00:17:35,219 Narrator: But finding exoplanets is no guarantee 344 00:17:35,221 --> 00:17:37,789 of finding alien life. 345 00:17:37,791 --> 00:17:41,025 And when it comes to contacting extraterrestrials, 346 00:17:41,027 --> 00:17:44,695 our efforts have met with silence. 347 00:17:44,697 --> 00:17:46,898 Oluseyi: Our search for life has come up empty. 348 00:17:46,900 --> 00:17:48,366 Do we need to change our tactics? 349 00:17:48,368 --> 00:17:50,001 Are we doing something wrong? 350 00:17:52,639 --> 00:17:54,005 Carroll: I think it's gonna be very, very hard 351 00:17:54,007 --> 00:17:56,240 to find extraterrestrial intelligence 352 00:17:56,242 --> 00:17:57,675 the way that we're looking for it. 353 00:17:57,677 --> 00:18:00,878 We would have to get really, really lucky. 354 00:18:00,880 --> 00:18:02,246 But I don't think we're gonna get lucky. 355 00:18:02,248 --> 00:18:03,448 I think that if we want to know 356 00:18:03,450 --> 00:18:05,016 whether there's life out there in the cosmos, 357 00:18:05,018 --> 00:18:06,684 we have to go visit it. 358 00:18:08,855 --> 00:18:10,555 Narrator: We've sent the new horizons probe 359 00:18:10,557 --> 00:18:15,293 billions of miles across the solar system to pluto. 360 00:18:15,295 --> 00:18:18,930 Perhaps one day we'll be able to send spacecraft 361 00:18:18,932 --> 00:18:20,398 across the universe 362 00:18:20,400 --> 00:18:24,035 to search for alien life on distant rogue planets. 363 00:18:24,037 --> 00:18:30,608 ? 364 00:18:30,610 --> 00:18:35,146 But if a craft left our galaxy to visit these new worlds, 365 00:18:35,148 --> 00:18:37,348 its mission would be tough 366 00:18:37,350 --> 00:18:40,718 thanks to the physics of the cosmos. 367 00:18:40,720 --> 00:18:44,322 From our perspective here in the milky way, 368 00:18:44,324 --> 00:18:49,126 every galaxy is, on average, receding away from us. 369 00:18:49,128 --> 00:18:51,429 It looks like nobody likes us 370 00:18:51,431 --> 00:18:55,933 and is trying to get as far away from us as possible. 371 00:18:55,935 --> 00:19:01,906 Narrator: This is because our giant universe is expanding. 372 00:19:01,908 --> 00:19:04,142 Freese: When we talk about the expanding universe, 373 00:19:04,144 --> 00:19:06,911 we don't mean that galaxies are doing something active 374 00:19:06,913 --> 00:19:09,747 to run away from one another. 375 00:19:09,749 --> 00:19:13,050 Actually, it's the underlying space that's expanding, 376 00:19:13,052 --> 00:19:14,619 and the galaxies are embedded in that, 377 00:19:14,621 --> 00:19:16,821 and that's what causes everything to move apart 378 00:19:16,823 --> 00:19:19,590 from everything else. 379 00:19:19,592 --> 00:19:21,058 Narrator: The regions of the universe 380 00:19:21,060 --> 00:19:23,661 within 3 million light-years of us 381 00:19:23,663 --> 00:19:27,632 are expanding at around 45 miles a second. 382 00:19:27,634 --> 00:19:31,969 That's over 160,000 miles an hour. 383 00:19:31,971 --> 00:19:33,804 Thaller: So with our current technology, 384 00:19:33,806 --> 00:19:35,606 do we have any chance of actually seeing 385 00:19:35,608 --> 00:19:37,675 what these other planets are like? 386 00:19:37,677 --> 00:19:39,777 Well, think about the fastest and farthest things 387 00:19:39,779 --> 00:19:42,246 we have right now, like the voyager spacecraft. 388 00:19:42,248 --> 00:19:44,215 They've been in space for more than 30 years 389 00:19:44,217 --> 00:19:48,452 going incredibly fast -- 38,000 miles an hour. 390 00:19:48,454 --> 00:19:52,857 Narrator: 38,000 miles an hour is fast. 391 00:19:52,859 --> 00:19:55,092 But the closest galaxies to us 392 00:19:55,094 --> 00:19:59,564 are moving away at over four times that speed. 393 00:19:59,566 --> 00:20:02,266 And the further away a probe is sent to travel, 394 00:20:02,268 --> 00:20:04,936 the tougher its task. 395 00:20:04,938 --> 00:20:06,437 The thing about the expansion of the universe 396 00:20:06,439 --> 00:20:08,606 is that the farther away something is, 397 00:20:08,608 --> 00:20:11,542 the faster it's moving away from you. 398 00:20:11,544 --> 00:20:14,812 The more distant two objects are away from each other, 399 00:20:14,814 --> 00:20:17,415 the more space there is between them, 400 00:20:17,417 --> 00:20:19,183 and the more space there is between them, 401 00:20:19,185 --> 00:20:23,854 the more space there is to expand. 402 00:20:23,856 --> 00:20:25,356 Oluseyi: The rate at which they're moving away 403 00:20:25,358 --> 00:20:27,024 is proportional to their distance. 404 00:20:27,026 --> 00:20:30,428 If it's twice as far away, it moves away twice as fast. 405 00:20:30,430 --> 00:20:31,829 It is three times farther away, 406 00:20:31,831 --> 00:20:34,899 and moves away three times as fast. 407 00:20:34,901 --> 00:20:37,034 Narrator: Scale it up to the planets we've discovered 408 00:20:37,036 --> 00:20:40,004 3.8 billion light-years away, 409 00:20:40,006 --> 00:20:42,540 and thanks to the expansion of the universe, 410 00:20:42,542 --> 00:20:46,344 those extra-galactic worlds are moving away from us 411 00:20:46,346 --> 00:20:51,749 at over 49,000 miles per second. 412 00:20:51,751 --> 00:20:54,018 Imagine that you're a runner, and you see the finish line. 413 00:20:54,020 --> 00:20:55,886 You're getting a bit closer to it, 414 00:20:55,888 --> 00:20:58,856 but now, actually, the track itself is expanding. 415 00:20:58,858 --> 00:21:01,292 And as the track expands faster and faster, 416 00:21:01,294 --> 00:21:04,262 it's expanding faster than you can possibly run. 417 00:21:04,264 --> 00:21:06,530 All of a sudden, that finish line starts receding, 418 00:21:06,532 --> 00:21:08,899 and you're never, ever gonna reach it. 419 00:21:12,505 --> 00:21:15,373 Narrator: Say one day we're able to build probes 420 00:21:15,375 --> 00:21:19,677 that travel at the fastest speed physics allows -- 421 00:21:19,679 --> 00:21:21,279 the speed of light. 422 00:21:23,850 --> 00:21:26,017 Even that might not be enough 423 00:21:26,019 --> 00:21:29,620 because sometimes the universe itself 424 00:21:29,622 --> 00:21:31,722 doesn't play by the rules. 425 00:21:31,724 --> 00:21:34,925 It's not possible for things to travel through space 426 00:21:34,927 --> 00:21:38,462 faster than the speed of light, but it is possible for space 427 00:21:38,464 --> 00:21:40,898 to expand faster than the speed of light. 428 00:21:40,900 --> 00:21:43,634 Tremblay: Everywhere we look, we see very distant galaxies 429 00:21:43,636 --> 00:21:46,237 that are apparently receding, or moving away from earth, 430 00:21:46,239 --> 00:21:48,439 at greater than the speed of light. 431 00:21:48,441 --> 00:21:50,641 Bullock: There are distant galaxies we can see in the sky that, 432 00:21:50,643 --> 00:21:53,611 even if we were to build the most advanced spaceship possible 433 00:21:53,613 --> 00:21:55,246 that could even move at the speed of light, 434 00:21:55,248 --> 00:21:57,348 we could never get there. 435 00:21:57,350 --> 00:22:01,319 97% of the galaxies that we can see in the distant sky 436 00:22:01,321 --> 00:22:05,189 are actually unreachable to us. 437 00:22:05,191 --> 00:22:07,525 Narrator: So for all the galaxies out there 438 00:22:07,527 --> 00:22:10,394 and all the planets that could harbor life, 439 00:22:10,396 --> 00:22:12,963 most of them are out of our reach. 440 00:22:15,702 --> 00:22:18,636 The physics of the universe has dealt an immense blow 441 00:22:18,638 --> 00:22:20,604 to first contact. 442 00:22:20,606 --> 00:22:23,974 The true reality of the universe will always be hidden from us 443 00:22:23,976 --> 00:22:27,812 because of this, because of this expansion. 444 00:22:27,814 --> 00:22:29,980 Narrator: The further we look out into the universe, 445 00:22:29,982 --> 00:22:35,086 the more unlikely first contact becomes. 446 00:22:35,088 --> 00:22:37,888 We might need an advanced alien race 447 00:22:37,890 --> 00:22:41,325 to come and visit us instead. 448 00:22:41,327 --> 00:22:43,260 Suppose we get that lucky. 449 00:22:43,262 --> 00:22:48,432 Even then, would first contact actually be feasible? 450 00:22:48,434 --> 00:22:49,934 Oluseyi: We think aliens are like us. 451 00:22:49,936 --> 00:22:51,102 They're not. 452 00:22:51,104 --> 00:22:53,170 We're assuming that the life is like us 453 00:22:53,172 --> 00:22:56,273 and that their planetary environment is like ours. 454 00:22:56,275 --> 00:22:58,242 I don't think that's gonna be the case 455 00:22:58,244 --> 00:23:00,978 for most of the life in the universe. 456 00:23:00,980 --> 00:23:03,581 Narrator: So, could extraterrestrials 457 00:23:03,583 --> 00:23:08,018 even survive first contact with us and our planet? 458 00:23:15,895 --> 00:23:18,095 [ Explosion ] 459 00:23:22,635 --> 00:23:26,036 Narrator: July 2019 -- 460 00:23:26,038 --> 00:23:29,707 the test satellite discovered a new alien world 461 00:23:29,709 --> 00:23:32,276 31 light-years from us 462 00:23:32,278 --> 00:23:36,013 named gj 357 d. 463 00:23:36,015 --> 00:23:38,916 At over six times the mass of our home planet, 464 00:23:38,918 --> 00:23:41,385 it's thought to be a super earth. 465 00:23:41,387 --> 00:23:43,454 And from our observations, 466 00:23:43,456 --> 00:23:47,291 super earths appear to be prime real estate. 467 00:23:47,293 --> 00:23:48,926 What we see is that the most common type 468 00:23:48,928 --> 00:23:52,263 of terrestrial planet is what we call a super earth. 469 00:23:52,265 --> 00:23:54,298 So that means it's a terrestrial planet, 470 00:23:54,300 --> 00:23:57,535 but much more massive. 471 00:23:57,537 --> 00:24:00,504 Narrator: More massive can mean more gravity, 472 00:24:00,506 --> 00:24:04,942 creating a planetary environment completely unlike our own 473 00:24:04,944 --> 00:24:08,712 and life completely unlike ours. 474 00:24:08,714 --> 00:24:10,748 Oluseyi: If they're on the surface of a super earth, 475 00:24:10,750 --> 00:24:14,452 it could be that gravity is gonna be way stronger. 476 00:24:14,454 --> 00:24:17,321 So these aliens aren't gonna be very tall, 477 00:24:17,323 --> 00:24:21,091 but they are gonna be very strong. 478 00:24:21,093 --> 00:24:23,661 Narrator: Super earths are just one of the many avenues 479 00:24:23,663 --> 00:24:25,763 the universe creates. 480 00:24:25,765 --> 00:24:29,200 There are other exoplanets orbiting red stars 481 00:24:29,202 --> 00:24:31,602 10 times smaller than our sun 482 00:24:31,604 --> 00:24:34,405 and others making binary systems 483 00:24:34,407 --> 00:24:38,509 comprising two stars instead of one. 484 00:24:38,511 --> 00:24:42,746 We see planets of all shapes and sizes around stars 485 00:24:42,748 --> 00:24:46,851 of all shapes and sizes, of all sorts of configurations. 486 00:24:46,853 --> 00:24:52,323 The potential for life is much more rich and varied 487 00:24:52,325 --> 00:24:54,425 than we ever thought before. 488 00:24:54,427 --> 00:24:59,163 Retro rockets five and six fired. 489 00:24:59,165 --> 00:25:00,598 Narrator: Images of science fiction 490 00:25:00,600 --> 00:25:03,834 have fueled numerous fantasies of first contact, 491 00:25:03,836 --> 00:25:06,237 but our knowledge of the universe suggests 492 00:25:06,239 --> 00:25:09,440 reality could be far, far stranger. 493 00:25:09,442 --> 00:25:10,841 If anything, Hollywood has kind of 494 00:25:10,843 --> 00:25:12,710 constrained our imagination 495 00:25:12,712 --> 00:25:15,212 in terms of presenting so many aliens 496 00:25:15,214 --> 00:25:17,214 that basically look like, you know, 497 00:25:17,216 --> 00:25:19,550 humans wearing a rubber suit or something. 498 00:25:19,552 --> 00:25:20,851 Lower landing legs. 499 00:25:23,022 --> 00:25:26,590 We have to, have to, let go of this obsession 500 00:25:26,592 --> 00:25:28,926 that they're gonna be anything like us. 501 00:25:28,928 --> 00:25:32,563 So if we're looking for two-legged dudes, forget it. 502 00:25:32,565 --> 00:25:39,436 ? 503 00:25:39,438 --> 00:25:42,139 Narrator: Say an intelligent alien species lives 504 00:25:42,141 --> 00:25:44,141 in our stellar neighborhood 505 00:25:44,143 --> 00:25:46,777 and wants to make first contact with us. 506 00:25:46,779 --> 00:25:49,513 If that alien evolved on a super earth 507 00:25:49,515 --> 00:25:53,250 or orbited a red star instead of a yellow one, 508 00:25:53,252 --> 00:25:55,452 it's wildly different biology 509 00:25:55,454 --> 00:25:58,088 may prevent it from ever setting foot, 510 00:25:58,090 --> 00:26:00,758 or tentacle, on planet earth. 511 00:26:04,463 --> 00:26:06,597 Stricker: When you look at life here on earth, 512 00:26:06,599 --> 00:26:08,532 it's almost as if it was custom-made 513 00:26:08,534 --> 00:26:10,334 for this temperature, for these elements, 514 00:26:10,336 --> 00:26:11,735 for this environment. 515 00:26:11,737 --> 00:26:14,371 An exoplanet with conditions to support life 516 00:26:14,373 --> 00:26:16,173 could still be completely different 517 00:26:16,175 --> 00:26:18,576 than life here on earth. 518 00:26:18,578 --> 00:26:20,578 Plait: What are things gonna be like on an alien world 519 00:26:20,580 --> 00:26:23,380 which has a little bit more potassium 520 00:26:23,382 --> 00:26:25,182 or is warmer than average on earth 521 00:26:25,184 --> 00:26:27,351 or has a thicker atmosphere? 522 00:26:27,353 --> 00:26:29,420 Each one of these small variations 523 00:26:29,422 --> 00:26:34,391 can mean a completely different ecosystem. 524 00:26:34,393 --> 00:26:36,760 Narrator: So could an alien organism 525 00:26:36,762 --> 00:26:40,798 really adapt to our ecosystem when it lands on earth? 526 00:26:43,069 --> 00:26:44,902 Maybe we haven't made first contact 527 00:26:44,904 --> 00:26:48,372 because they can't actually visit us. 528 00:26:48,374 --> 00:26:50,240 Dartnell: They could step through the airlock 529 00:26:50,242 --> 00:26:52,476 of their spaceship and onto the earth 530 00:26:52,478 --> 00:26:55,546 and just find something toxic with our environment, 531 00:26:55,548 --> 00:26:57,448 some some reason they're not compatible 532 00:26:57,450 --> 00:26:59,350 with the surface of the earth. 533 00:26:59,352 --> 00:27:03,253 It's almost as if the universe is out there 534 00:27:03,255 --> 00:27:07,324 deliberately trying to stop us meeting any aliens. 535 00:27:07,326 --> 00:27:09,059 Narrator: Biology creates another obstacle 536 00:27:09,061 --> 00:27:11,095 for making first contact, 537 00:27:11,097 --> 00:27:14,298 but as planetary scientist jani radebough finds, 538 00:27:14,300 --> 00:27:17,134 even life on earth can get pretty weird, 539 00:27:17,136 --> 00:27:18,969 taking extreme measures to adapt 540 00:27:18,971 --> 00:27:21,805 to a potentially hostile environment. 541 00:27:21,807 --> 00:27:23,340 Radebough: This is the great salt lake. 542 00:27:23,342 --> 00:27:25,109 It is the remains of what used to be 543 00:27:25,111 --> 00:27:27,244 a much larger lake in the past. 544 00:27:27,246 --> 00:27:32,916 And when it evaporated away, it left behind all of the salt. 545 00:27:32,918 --> 00:27:35,919 Narrator: The great salt lake is nearly 10 times saltier 546 00:27:35,921 --> 00:27:38,155 than earth's oceans. 547 00:27:38,157 --> 00:27:39,857 The extreme salt content 548 00:27:39,859 --> 00:27:44,428 should make it an inhospitable place for life. 549 00:27:44,430 --> 00:27:48,666 Despite this, there are organisms thriving in the water. 550 00:27:50,569 --> 00:27:52,903 Radebough: As we look at life in this vast lake 551 00:27:52,905 --> 00:27:55,406 and find that there are billions of microbes living here 552 00:27:55,408 --> 00:27:58,609 in this unexpected environment, then we start to realize, 553 00:27:58,611 --> 00:28:01,812 well, life forms in ways that we just don't expect, 554 00:28:01,814 --> 00:28:03,781 in places we don't expect. 555 00:28:03,783 --> 00:28:07,718 Narrator: Microbial life known as extremophiles 556 00:28:07,720 --> 00:28:11,422 have developed an ingenious way to survive in the lake. 557 00:28:11,424 --> 00:28:13,524 Well, they actually use these solar-powered pumps 558 00:28:13,526 --> 00:28:15,826 to pull the salt out of their cells 559 00:28:15,828 --> 00:28:18,128 so that they can operate more normally. 560 00:28:18,130 --> 00:28:19,530 But in order to do that, they have to live 561 00:28:19,532 --> 00:28:20,831 very close to the surface, 562 00:28:20,833 --> 00:28:23,734 which means they get a huge amount of U.V. radiation. 563 00:28:23,736 --> 00:28:26,837 So all this pink color that you see behind me 564 00:28:26,839 --> 00:28:29,139 is actually the pink of the organisms, 565 00:28:29,141 --> 00:28:31,208 and it's sort of like a built-in sunscreen 566 00:28:31,210 --> 00:28:34,611 that helps protect them against the U.V. radiation. 567 00:28:34,613 --> 00:28:38,482 Narrator: Extremophiles are rewriting our expectations 568 00:28:38,484 --> 00:28:41,218 of where life can survive on earth. 569 00:28:41,220 --> 00:28:45,956 Could alien biology be much more resilient than we think? 570 00:28:45,958 --> 00:28:48,726 These extremophiles should be a little reminder 571 00:28:48,728 --> 00:28:52,429 that we haven't been thinking big enough. 572 00:28:52,431 --> 00:28:56,667 Narrator: Maybe e.T. Could readily adapt to our environment, 573 00:28:56,669 --> 00:28:59,636 or perhaps they've got other ideas, 574 00:28:59,638 --> 00:29:04,441 using technology to overcome any biological barriers. 575 00:29:04,443 --> 00:29:09,146 Maybe the first aliens we meet will be robots. 576 00:29:09,148 --> 00:29:11,315 They can build much more powerful life 577 00:29:11,317 --> 00:29:14,017 if they don't limit themselves to meat bags. 578 00:29:14,019 --> 00:29:15,786 Narrator: Advanced aliens could have left 579 00:29:15,788 --> 00:29:18,922 their biological brains and bodies behind, 580 00:29:18,924 --> 00:29:24,495 traveling instead as mobile artificial intelligence. 581 00:29:24,497 --> 00:29:27,064 Tegmark: We tend to think of intelligence and consciousness 582 00:29:27,066 --> 00:29:29,299 as something mysterious that can only exist 583 00:29:29,301 --> 00:29:31,969 inside of biological organisms like us 584 00:29:31,971 --> 00:29:36,006 and somehow therefore can't be copied. 585 00:29:36,008 --> 00:29:39,076 But what's given us the whole a.I. Revolution, right -- 586 00:29:39,078 --> 00:29:40,277 the idea that, no, 587 00:29:40,279 --> 00:29:42,446 intelligence and probably consciousness, too, 588 00:29:42,448 --> 00:29:44,381 is just information processing, 589 00:29:44,383 --> 00:29:47,017 and it's just the information processing that really matters. 590 00:29:47,019 --> 00:29:50,087 Perhaps an alien would be able to download 591 00:29:50,089 --> 00:29:53,190 its consciousness into some sort of computer 592 00:29:53,192 --> 00:29:58,395 and travel as a disembodied consciousness. 593 00:29:58,397 --> 00:30:01,498 In this state, you'd be essentially immortal. 594 00:30:06,005 --> 00:30:09,106 Narrator: So it's possible an advanced species could find ways 595 00:30:09,108 --> 00:30:13,544 to face the challenges of first contact. 596 00:30:13,546 --> 00:30:16,780 But if an alien civilization is out there 597 00:30:16,782 --> 00:30:18,515 and more advanced than us, 598 00:30:18,517 --> 00:30:22,486 could there be an even bigger issue at play? 599 00:30:22,488 --> 00:30:25,489 Maybe the reason that intelligent aliens 600 00:30:25,491 --> 00:30:28,392 haven't ever come to the earth to visit us 601 00:30:28,394 --> 00:30:32,129 is maybe we're just not that interesting. 602 00:30:32,131 --> 00:30:35,132 Narrator: So maybe the biggest barrier for first contact 603 00:30:35,134 --> 00:30:39,169 is the fact that aliens don't actually want to meet us. 604 00:30:48,347 --> 00:30:50,414 [ Explosion ] 605 00:30:52,818 --> 00:30:55,786 ? 606 00:30:55,788 --> 00:30:58,622 Narrator: In the movies, first contact usually leads 607 00:30:58,624 --> 00:31:01,325 to an alien invasion. 608 00:31:01,327 --> 00:31:03,360 Cities get zapped. 609 00:31:03,362 --> 00:31:05,495 [ Explosion ] 610 00:31:09,068 --> 00:31:12,035 Humanity faces annihilation. 611 00:31:12,037 --> 00:31:12,936 [ People screaming ] 612 00:31:12,938 --> 00:31:15,339 Maybe a visit from e.T. 613 00:31:15,341 --> 00:31:18,242 Isn't such a good thing, after all. 614 00:31:18,244 --> 00:31:21,979 Imagine if we if we got an intergalactic e-mail, 615 00:31:21,981 --> 00:31:25,983 so from, you know, superioraliencivilization. Org, 616 00:31:25,985 --> 00:31:29,219 saying, "hey, we're gonna show up in 30 years." 617 00:31:29,221 --> 00:31:30,621 Would we just be like, "oh, all right, 618 00:31:30,623 --> 00:31:33,390 let's get back to watching our reality TV shows 619 00:31:33,392 --> 00:31:34,958 and worry about that when they get here"? 620 00:31:34,960 --> 00:31:37,628 No, we would seriously freak out. 621 00:31:37,630 --> 00:31:41,265 Narrator: People might freak out, 622 00:31:41,267 --> 00:31:44,534 but the truth is we've been sign-posting our location 623 00:31:44,536 --> 00:31:47,037 into the cosmos for decades. 624 00:31:47,039 --> 00:31:51,074 Dartnell: The earth has been a detectably technological world 625 00:31:51,076 --> 00:31:52,576 for about 100 years. 626 00:31:52,578 --> 00:31:55,012 We've been broadcasting signals, 627 00:31:55,014 --> 00:32:00,250 and yet, that apparently hasn't attracted anyone's attention. 628 00:32:00,252 --> 00:32:01,985 It's pretty noteworthy 629 00:32:01,987 --> 00:32:04,521 that none of them has shown any interest, 630 00:32:04,523 --> 00:32:06,957 when they could have turned earth into a parking lot 631 00:32:06,959 --> 00:32:09,393 if they wanted, right? 632 00:32:09,395 --> 00:32:12,362 Narrator: Perhaps no one has redeveloped planet earth 633 00:32:12,364 --> 00:32:15,032 because an advanced civilization 634 00:32:15,034 --> 00:32:18,669 simply doesn't want to make first contact. 635 00:32:18,671 --> 00:32:20,203 Frankly, if they're that intelligent, 636 00:32:20,205 --> 00:32:23,106 they're not gonna be very interested in us. 637 00:32:23,108 --> 00:32:26,209 So maybe that's why they haven't bothered to make contact. 638 00:32:26,211 --> 00:32:28,412 Filippenko: And if the alien is that advanced, 639 00:32:28,414 --> 00:32:31,548 we're probably not very interesting to it. 640 00:32:31,550 --> 00:32:33,717 It's a little bit like, you know, 641 00:32:33,719 --> 00:32:38,021 wandering around outside and seeing ants on the sidewalk. 642 00:32:40,059 --> 00:32:43,694 Narrator: Alien invasion makes for great science fiction, 643 00:32:43,696 --> 00:32:45,829 but what do we actually have on earth 644 00:32:45,831 --> 00:32:49,299 that's worth all that alien effort? 645 00:32:49,301 --> 00:32:51,001 Dartnell: How realistic really are 646 00:32:51,003 --> 00:32:53,971 these depictions from Hollywood? 647 00:32:53,973 --> 00:32:59,676 One common trope is the aliens coming to devour the human race. 648 00:32:59,678 --> 00:33:03,113 But the science doesn't really support this being possible. 649 00:33:03,115 --> 00:33:09,019 Would an alien even be able to digest the human body? 650 00:33:09,021 --> 00:33:12,289 Narrator: When eating, enzymes in our digestive system 651 00:33:12,291 --> 00:33:15,392 break down molecules in our food. 652 00:33:15,394 --> 00:33:19,663 The food we can eat, and these enzymes are very specific 653 00:33:19,665 --> 00:33:23,600 to the molecules they can attack and break down. 654 00:33:23,602 --> 00:33:27,404 The same rules would apply to a hungry alien. 655 00:33:27,406 --> 00:33:29,072 Dartnell: To be able to digest us 656 00:33:29,074 --> 00:33:31,074 and for us to be nutritious for them, 657 00:33:31,076 --> 00:33:33,944 we'd have to have a very, very similar biochemistry 658 00:33:33,946 --> 00:33:36,680 to what exists on the alien's home world, 659 00:33:36,682 --> 00:33:39,850 what their bodies have adapted to. 660 00:33:39,852 --> 00:33:42,052 Narrator: So it seems highly unlikely 661 00:33:42,054 --> 00:33:44,621 that aliens would come looking for food. 662 00:33:44,623 --> 00:33:47,257 But how about a drink? 663 00:33:47,259 --> 00:33:50,227 In order for life as we know it to exist, 664 00:33:50,229 --> 00:33:52,596 one needs liquid water. 665 00:33:52,598 --> 00:33:55,866 Narrator: If aliens live on a barren desert planet, 666 00:33:55,868 --> 00:34:00,537 a water world like ours could be highly attractive. 667 00:34:00,539 --> 00:34:03,206 While we call ourselves the blue planet, 668 00:34:03,208 --> 00:34:05,842 our oceans are not unique. 669 00:34:05,844 --> 00:34:10,614 The universe offers far greater water resources. 670 00:34:10,616 --> 00:34:12,282 Sutter: In our solar system, we're finding that 671 00:34:12,284 --> 00:34:18,555 most of the liquid water exists in moons around the gas giants. 672 00:34:18,557 --> 00:34:20,957 Narrator: We believe Jupiter's moon europa 673 00:34:20,959 --> 00:34:25,462 has a layer of water ice around 15 miles thick 674 00:34:25,464 --> 00:34:29,533 floating on an ocean up to 100 miles deep. 675 00:34:29,535 --> 00:34:32,869 This single moon may have twice as much water 676 00:34:32,871 --> 00:34:36,206 as all earth's oceans combined. 677 00:34:36,208 --> 00:34:39,543 Europa is the water world of our solar system 678 00:34:39,545 --> 00:34:41,178 and not the earth. 679 00:34:41,180 --> 00:34:44,581 So if you were an alien looking for water, 680 00:34:44,583 --> 00:34:47,951 you wouldn't bother going to a big planet like the earth 681 00:34:47,953 --> 00:34:50,720 to suck it up through some kind of giant straw. 682 00:34:50,722 --> 00:34:52,856 You'd go to the outer solar system. 683 00:34:52,858 --> 00:34:56,960 You might harvest icy moons. 684 00:34:56,962 --> 00:34:58,628 Narrator: Instead of working against 685 00:34:58,630 --> 00:35:01,865 the powerful gravitational pull of earth, 686 00:35:01,867 --> 00:35:05,469 an alien race could draw water from europa, 687 00:35:05,471 --> 00:35:09,473 where gravity is almost 10 times weaker. 688 00:35:09,475 --> 00:35:13,410 So what other resources have we got to offer? 689 00:35:13,412 --> 00:35:17,948 Maybe aliens come to strip mine the earth's crust 690 00:35:17,950 --> 00:35:22,652 for metals -- iron or titanium or platinum. 691 00:35:22,654 --> 00:35:24,121 Aliens might use these metals 692 00:35:24,123 --> 00:35:26,356 for exactly the same things that we do -- 693 00:35:26,358 --> 00:35:29,993 for building spaceships, for building their technology. 694 00:35:32,464 --> 00:35:34,297 Narrator: Such materials could be useful 695 00:35:34,299 --> 00:35:38,802 for any alien civilization short on mineral resources. 696 00:35:38,804 --> 00:35:41,505 Problem is, a lot of our planet's metals 697 00:35:41,507 --> 00:35:45,008 are buried deep in the earth's interior. 698 00:35:45,010 --> 00:35:48,545 When the earth formed, the great deal of its iron 699 00:35:48,547 --> 00:35:50,947 sunk down into the core of our planet 700 00:35:50,949 --> 00:35:52,482 and took a lot of metals with it. 701 00:35:52,484 --> 00:35:56,453 So they're actually quite hard to mine on the earth. 702 00:35:56,455 --> 00:35:58,989 Narrator: An alien race would be better off prospecting 703 00:35:58,991 --> 00:36:04,694 for more accessible minerals situated in the asteroid belt. 704 00:36:04,696 --> 00:36:07,597 In the asteroid belt, there's an asteroid called psyche, 705 00:36:07,599 --> 00:36:10,000 which is made up of pure iron nickel, 706 00:36:10,002 --> 00:36:12,802 just like the core of the earth. 707 00:36:12,804 --> 00:36:16,039 Narrator: Psyche provides a near-150-mile 708 00:36:16,041 --> 00:36:19,376 exposed strip of iron nickel, 709 00:36:19,378 --> 00:36:24,447 yet another reason e.T. Wouldn't need to bother with us. 710 00:36:24,449 --> 00:36:26,883 For my money, none of those reasons 711 00:36:26,885 --> 00:36:29,553 would draw aliens to earth. 712 00:36:29,555 --> 00:36:32,889 All these things can be found far more easily elsewhere. 713 00:36:32,891 --> 00:36:34,824 Narrator: The possibility of first contact 714 00:36:34,826 --> 00:36:37,928 is beginning to sound increasingly remote. 715 00:36:37,930 --> 00:36:40,430 The universe throws up massive barriers 716 00:36:40,432 --> 00:36:44,801 stopping us from communicating with an intelligent alien race, 717 00:36:44,803 --> 00:36:48,205 a race that might very well have absolutely no interest 718 00:36:48,207 --> 00:36:50,106 in contacting us, 719 00:36:50,108 --> 00:36:53,276 unless, of course, they already have. 720 00:36:53,278 --> 00:36:55,312 Is it possible that there have been alien signals 721 00:36:55,314 --> 00:36:58,782 that we've already detected but we didn't realize what they are? 722 00:36:58,784 --> 00:37:00,350 Narrator: Scientists have discovered 723 00:37:00,352 --> 00:37:05,155 a powerful cosmic signal that they cannot explain. 724 00:37:05,157 --> 00:37:08,825 Could this finally be first contact? 725 00:37:16,835 --> 00:37:18,868 [ Explosion ] 726 00:37:23,275 --> 00:37:26,710 Narrator: July 2018 -- 727 00:37:26,712 --> 00:37:29,179 the chime telescope in British Columbia 728 00:37:29,181 --> 00:37:32,249 detected a short flash of radio energy 729 00:37:32,251 --> 00:37:34,451 quicker than a blinking eye. 730 00:37:34,453 --> 00:37:38,221 It's called a fast radio burst. 731 00:37:38,223 --> 00:37:41,057 These are intensely powerful, very, very short 732 00:37:41,059 --> 00:37:43,793 lived radio bursts that can be 1,000 times brighter 733 00:37:43,795 --> 00:37:45,862 than the sun at radio wavelengths, 734 00:37:45,864 --> 00:37:49,466 that arrive and disappear in an instant. 735 00:37:52,170 --> 00:37:54,871 Narrator: Most fast radio bursts are one-offs, 736 00:37:54,873 --> 00:37:59,242 blinking into existence, then disappearing forever. 737 00:37:59,244 --> 00:38:01,077 But not this one. 738 00:38:01,079 --> 00:38:05,749 A few days later, scientists caught the flash again. 739 00:38:05,751 --> 00:38:07,984 The amount of energy that it takes to produce 740 00:38:07,986 --> 00:38:09,185 a burst like this, 741 00:38:09,187 --> 00:38:10,987 for us to detect it here on earth 742 00:38:10,989 --> 00:38:14,257 from billions of light-years, is immense. 743 00:38:14,259 --> 00:38:17,060 And we've run across things like this before -- 744 00:38:17,062 --> 00:38:19,362 exploding stars, gamma-ray bursts. 745 00:38:19,364 --> 00:38:21,765 These are all very strange objects, 746 00:38:21,767 --> 00:38:23,700 but that does not explain these 747 00:38:23,702 --> 00:38:26,903 because some of these fast radio bursts repeat. 748 00:38:26,905 --> 00:38:29,673 So whatever it is that can generate this kind of energy, 749 00:38:29,675 --> 00:38:31,441 it can do it more than once. 750 00:38:36,114 --> 00:38:39,149 Narrator: Light comes in many different wavelengths. 751 00:38:39,151 --> 00:38:41,951 Radio waves are the longest, making them good 752 00:38:41,953 --> 00:38:44,087 for long-distance communication. 753 00:38:46,358 --> 00:38:49,159 We've used radio waves for over 100 years, 754 00:38:49,161 --> 00:38:52,929 from wireless radio to TV, 755 00:38:52,931 --> 00:38:55,565 from cellphone calls to communications 756 00:38:55,567 --> 00:38:58,101 with space probes. 757 00:38:58,103 --> 00:39:01,304 Could alien civilizations be using radio waves, 758 00:39:01,306 --> 00:39:04,574 but on a much larger scale? 759 00:39:04,576 --> 00:39:07,344 What if we already intercepted alien communications, 760 00:39:07,346 --> 00:39:10,480 but we just don't know it? 761 00:39:10,482 --> 00:39:12,349 Narrator: Our radio and television signals 762 00:39:12,351 --> 00:39:17,220 only use a very narrow band of the radio spectrum. 763 00:39:17,222 --> 00:39:19,923 Fast radio bursts are different, 764 00:39:19,925 --> 00:39:22,192 and that's a problem. 765 00:39:22,194 --> 00:39:24,160 Here's the thing about fast radio bursts -- 766 00:39:24,162 --> 00:39:26,629 they are emitting a broad range of wavelengths, 767 00:39:26,631 --> 00:39:28,765 so it's not the best way to communicate. 768 00:39:28,767 --> 00:39:33,636 If these are aliens, they're not very smart aliens. 769 00:39:33,638 --> 00:39:36,606 Narrator: It turns out that broad-range wavelengths 770 00:39:36,608 --> 00:39:38,475 are easy to distort. 771 00:39:38,477 --> 00:39:42,445 There is a very thin gas out there between the stars, 772 00:39:42,447 --> 00:39:44,180 and when you emit radio waves, 773 00:39:44,182 --> 00:39:46,616 the radio waves interact with this gas. 774 00:39:46,618 --> 00:39:47,951 And the way they interact 775 00:39:47,953 --> 00:39:51,554 depends on the wavelength you're talking about. 776 00:39:51,556 --> 00:39:53,757 If you use a broad range of wavelengths 777 00:39:53,759 --> 00:39:56,259 to send a signal across interstellar space, 778 00:39:56,261 --> 00:39:57,727 by the time somebody receives it, 779 00:39:57,729 --> 00:39:59,929 it can be a little distorted and weird. 780 00:40:02,801 --> 00:40:05,402 Narrator: If aliens are sending out radio bursts, 781 00:40:05,404 --> 00:40:09,839 the signal would get so degraded that by the time it reaches us, 782 00:40:09,841 --> 00:40:13,877 we wouldn't be able to decipher it. 783 00:40:13,879 --> 00:40:18,081 As a calling card, not incredibly useful. 784 00:40:18,083 --> 00:40:20,283 Narrator: Whether these mysterious bursts really are 785 00:40:20,285 --> 00:40:24,687 aliens trying to say hello or just a natural phenomenon, 786 00:40:24,689 --> 00:40:27,157 this is not first contact, 787 00:40:27,159 --> 00:40:29,125 at least not yet. 788 00:40:29,127 --> 00:40:30,727 I want to be careful here, right? 789 00:40:30,729 --> 00:40:33,730 I'm not a naysayer. I'm not gonna pooh-pooh aliens. 790 00:40:33,732 --> 00:40:35,598 But, you know, let's go through the other things first 791 00:40:35,600 --> 00:40:38,268 because the universe is filled with weird stuff, 792 00:40:38,270 --> 00:40:39,836 and let's see what that is. 793 00:40:39,838 --> 00:40:43,006 And if we eliminate all those, and all that's left is aliens, 794 00:40:43,008 --> 00:40:45,475 yeah, let's talk. 795 00:40:45,477 --> 00:40:49,212 Narrator: If extraterrestrial species are out there, 796 00:40:49,214 --> 00:40:51,748 our universe makes it extremely difficult 797 00:40:51,750 --> 00:40:54,784 to contact them. 798 00:40:54,786 --> 00:40:57,120 But in spite of all the obstacles, 799 00:40:57,122 --> 00:40:59,088 maybe there's still hope. 800 00:41:01,393 --> 00:41:03,893 We once thought that there could be 10,000 801 00:41:03,895 --> 00:41:07,964 intelligent civilizations in the milky way alone. 802 00:41:07,966 --> 00:41:11,468 Now we know that our cosmos is filled with planets 803 00:41:11,470 --> 00:41:14,070 just waiting to be found. 804 00:41:14,072 --> 00:41:16,172 Our technology is evolving. 805 00:41:16,174 --> 00:41:18,408 Searches are expanding. 806 00:41:18,410 --> 00:41:22,245 The truth about our mission to make first contact is this -- 807 00:41:22,247 --> 00:41:27,584 we are only just getting started. 808 00:41:27,586 --> 00:41:32,188 I'd love for tomorrow morning some sort of interstellar tweet 809 00:41:32,190 --> 00:41:33,890 to be beamed at the earth, 810 00:41:33,892 --> 00:41:35,391 and we would then realize 811 00:41:35,393 --> 00:41:38,695 that we are not alone in this cosmos. 812 00:41:38,697 --> 00:41:39,929 Pacini: I'm all ready to celebrate. 813 00:41:39,931 --> 00:41:42,665 Here we have already a champagne on ice 814 00:41:42,667 --> 00:41:46,035 [laughs] To pop when they find it. 815 00:41:46,037 --> 00:41:49,072 Thaller: Scientists really do hope we find evidence 816 00:41:49,074 --> 00:41:51,274 of extraterrestrial life someday. 817 00:41:51,276 --> 00:41:54,644 We have observatories and satellites that look at the sky. 818 00:41:54,646 --> 00:41:58,481 All day, all night, every day. 819 00:41:58,483 --> 00:42:01,951 The discovery of alien life would simultaneously be, 820 00:42:01,953 --> 00:42:03,786 in a way, unsurprising 821 00:42:03,788 --> 00:42:07,257 and yet the greatest discovery in all of human history. 822 00:42:07,259 --> 00:42:09,125 Even if life is really, really rare, 823 00:42:09,127 --> 00:42:11,060 the universe is really, really big, 824 00:42:11,062 --> 00:42:14,397 and so there could be countless alien civilizations out there. 825 00:42:14,399 --> 00:42:17,200 But the actual discovery or confirmation of that -- 826 00:42:17,202 --> 00:42:19,969 I can think of no greater scientific discovery. 827 00:42:19,971 --> 00:42:23,139 It would quite literally change our entire civilization. 828 00:42:23,141 --> 00:42:27,677 ? 829 00:42:27,727 --> 00:42:32,277 Repair and Synchronization by Easy Subtitles Synchronizer 1.0.0.0 66751

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