1 00:00:02,691 --> 00:00:05,524 {\an8}(dramatic music) 2 00:00:13,770 --> 00:00:16,090 Since the very beginning of time, 3 00:00:16,090 --> 00:00:18,400 man has looked to the night sky 4 00:00:18,400 --> 00:00:20,513 and asked the same questions. 5 00:00:23,140 --> 00:00:24,700 Where are we? 6 00:00:24,700 --> 00:00:27,400 How far do the stars go? 7 00:00:27,400 --> 00:00:29,181 And are we alone? 8 00:00:29,181 --> 00:00:30,920 (dramatic music) 9 00:00:30,920 --> 00:00:34,180 Today, these same questions linger in the minds 10 00:00:34,180 --> 00:00:36,893 of every human with an inquisitive nature. 11 00:00:39,320 --> 00:00:43,010 Is our world just a speck in an infinite universe, 12 00:00:43,010 --> 00:00:45,763 surrounded by many other worlds and species, 13 00:00:46,760 --> 00:00:50,570 or is it possible that we are the only intelligent life 14 00:00:50,570 --> 00:00:52,553 in the universe? 15 00:00:52,553 --> 00:00:54,740 (dramatic music) 16 00:00:54,740 --> 00:00:57,400 If our universe is truly infinite 17 00:00:57,400 --> 00:01:00,070 then it is thought that anything that could happen 18 00:01:00,070 --> 00:01:03,183 has happened an infinite number of times. 19 00:01:04,530 --> 00:01:06,520 There will be infinite worlds 20 00:01:06,520 --> 00:01:08,870 and infinite intelligent life forms, 21 00:01:08,870 --> 00:01:11,993 even infinite copies of ourselves, 22 00:01:11,993 --> 00:01:14,050 (dramatic music) 23 00:01:14,050 --> 00:01:17,460 but we may also exist in an infinite universe, 24 00:01:17,460 --> 00:01:20,430 which is one of infinitely many universes 25 00:01:20,430 --> 00:01:24,132 each existing in possibly infinite dimensions. 26 00:01:24,132 --> 00:01:27,230 (dramatic music) 27 00:01:27,230 --> 00:01:29,850 We will explore the many theories and ideas 28 00:01:29,850 --> 00:01:32,560 as to where we all are in this immense system, 29 00:01:32,560 --> 00:01:34,080 which seemed to come from nothing 30 00:01:34,080 --> 00:01:38,059 in the Big Bang 13.8 billion years ago. 31 00:01:38,059 --> 00:01:40,120 (dramatic music) 32 00:01:40,120 --> 00:01:43,203 New understanding says this may not be the full story. 33 00:01:45,280 --> 00:01:49,140 We look at the ideas and theories from a human perspective 34 00:01:49,140 --> 00:01:52,020 and hear from our best scientific minds, 35 00:01:52,020 --> 00:01:54,180 who spend their lives trying to understand 36 00:01:54,180 --> 00:01:55,763 these monumental concepts. 37 00:01:57,400 --> 00:01:59,640 How do we try and understand 38 00:01:59,640 --> 00:02:03,260 what may be simply beyond human comprehension? 39 00:02:03,260 --> 00:02:06,010 (dramatic music) 40 00:02:32,101 --> 00:02:34,684 (radio static) 41 00:02:38,513 --> 00:02:41,596 Are we the only life in the universe? 42 00:02:43,610 --> 00:02:47,430 Given that the universe is thought to be spatially infinite, 43 00:02:47,430 --> 00:02:50,190 then it would seem impossible that our world 44 00:02:50,190 --> 00:02:53,313 is the only world to have started life. 45 00:02:55,760 --> 00:02:59,070 If life exists elsewhere in the universe, 46 00:02:59,070 --> 00:03:02,503 then will we ever meet another intelligent race? 47 00:03:04,000 --> 00:03:06,080 Unfortunately, we have to go back 48 00:03:06,080 --> 00:03:08,370 to the sheer scale of the universe 49 00:03:08,370 --> 00:03:11,400 to realize that even our closest neighbors 50 00:03:11,400 --> 00:03:14,063 would take many light years to reach. 51 00:03:15,775 --> 00:03:19,120 (dramatic music) 52 00:03:19,120 --> 00:03:22,000 Life could exist in so many forms 53 00:03:22,000 --> 00:03:25,363 that we would not even recognize it to be a living entity. 54 00:03:28,610 --> 00:03:32,070 Life might be so short-lived that it has come in 55 00:03:32,070 --> 00:03:34,460 and out of existence in less time 56 00:03:34,460 --> 00:03:36,557 than we can conceive of it. 57 00:03:36,557 --> 00:03:39,390 (dramatic music) 58 00:03:40,536 --> 00:03:45,286 Or so vast and old that it is part of the universe itself 59 00:03:46,250 --> 00:03:49,688 without us even knowing of its existence. 60 00:03:49,688 --> 00:03:52,521 (dramatic music) 61 00:03:58,400 --> 00:04:02,210 Life could exist in different dimensions to ours, 62 00:04:02,210 --> 00:04:04,843 and again, we will never know of its presence. 63 00:04:06,151 --> 00:04:08,984 (dramatic music) 64 00:04:16,862 --> 00:04:19,090 As humans, we yearn to know 65 00:04:19,090 --> 00:04:21,333 if we're the only intelligent life, 66 00:04:22,210 --> 00:04:24,940 but what would it mean if we did discover 67 00:04:24,940 --> 00:04:26,783 another superior life form? 68 00:04:28,560 --> 00:04:31,300 We consider ourselves to be sophisticated, 69 00:04:31,300 --> 00:04:36,030 intelligent beings, but to another more advanced race 70 00:04:36,030 --> 00:04:39,661 we could appear to them as ants do to us. 71 00:04:39,661 --> 00:04:42,494 (dramatic music) 72 00:04:43,450 --> 00:04:47,033 {\an8}At the heart of all human is the fear of being alone. 73 00:04:48,870 --> 00:04:52,070 I hope there is more out there than just us, 74 00:04:52,070 --> 00:04:56,510 because otherwise it kind of makes us assume this big ego, 75 00:04:56,510 --> 00:04:59,480 and I think we have taken on this big ego of that 76 00:04:59,480 --> 00:05:03,180 we are all there is and we are all that will ever be. 77 00:05:03,180 --> 00:05:04,730 {\an8}Maybe it's stupid that we are thinking 78 00:05:04,730 --> 00:05:07,730 {\an8}that there only is one world where we are living in 79 00:05:07,730 --> 00:05:10,360 because it's infinity, so maybe it's like thousands 80 00:05:10,360 --> 00:05:11,930 and thousands of miles away. 81 00:05:11,930 --> 00:05:14,267 Another world with other people on it 82 00:05:14,267 --> 00:05:16,640 and we cannot reach them or see them, 83 00:05:16,640 --> 00:05:18,636 but maybe they're out there. 84 00:05:18,636 --> 00:05:20,490 (dramatic music) 85 00:05:20,490 --> 00:05:22,900 {\an8}In an infinite universe, other life has of course, 86 00:05:22,900 --> 00:05:26,353 {\an8}got to exist, everything has got to exist. 87 00:05:28,260 --> 00:05:31,210 But whether there's other intelligent life out there, 88 00:05:31,210 --> 00:05:33,410 that becomes a much more difficult question. 89 00:05:35,380 --> 00:05:38,530 I believe that there's more than we can see now. 90 00:05:38,530 --> 00:05:40,960 Maybe aliens, I don't know, 91 00:05:40,960 --> 00:05:44,310 because we also popped up in once with the Big Bang, 92 00:05:44,310 --> 00:05:47,880 so they can also be on the other planets. 93 00:05:47,880 --> 00:05:49,620 Maybe they are hiding from us, you don't know. 94 00:05:49,620 --> 00:05:51,900 Do they don't wanna show themselves? 95 00:05:53,440 --> 00:05:56,200 We certainly are not the only form of life. 96 00:05:56,200 --> 00:06:00,050 {\an8}We just can't be, not when you look at the vastness 97 00:06:00,050 --> 00:06:01,213 {\an8}of what is the cosmos. 98 00:06:03,120 --> 00:06:05,370 The universe is filled with stars and galaxies, 99 00:06:05,370 --> 00:06:07,523 and super massive black holes. 100 00:06:08,830 --> 00:06:10,300 {\an8}The universe is filled with dark energy 101 00:06:10,300 --> 00:06:12,650 {\an8}that we're not really sure what it is. 102 00:06:12,650 --> 00:06:15,310 {\an8}Maybe dark energy is some type of alien 103 00:06:15,310 --> 00:06:17,510 that we haven't figured out what it is. 104 00:06:17,510 --> 00:06:18,880 All the aliens have evolved into 105 00:06:18,880 --> 00:06:20,450 dark matter, virtual particles 106 00:06:20,450 --> 00:06:22,530 and they just fluctuate around and talk to each other 107 00:06:22,530 --> 00:06:24,710 and do whatever they do, and we just think 108 00:06:24,710 --> 00:06:26,360 it's the structure of the vacuum. 109 00:06:32,720 --> 00:06:36,110 In the 1960s, an equation was formulated 110 00:06:36,110 --> 00:06:39,040 to try to answer the question of the probability 111 00:06:39,040 --> 00:06:44,003 and frequency of contactable intelligent life in our galaxy. 112 00:06:45,380 --> 00:06:47,830 It was called the Drake equation 113 00:06:47,830 --> 00:06:50,720 and it predicted that there would be conservatively 114 00:06:50,720 --> 00:06:55,273 4,000 planets with intelligent life in our galaxy alone. 115 00:06:57,230 --> 00:07:00,710 Since then the estimate of this figure has increased 116 00:07:00,710 --> 00:07:02,373 by an amazing amount. 117 00:07:03,720 --> 00:07:06,830 What is our new understanding of the possibility 118 00:07:06,830 --> 00:07:09,803 that there is other life in our universe? 119 00:07:11,300 --> 00:07:15,280 {\an8}I think the prospect of life out in the universe 120 00:07:15,280 --> 00:07:17,967 {\an8}is reasonably high because the conditions here 121 00:07:17,967 --> 00:07:20,030 and the conditions out there 122 00:07:20,030 --> 00:07:21,610 are probably gonna be quite similar. 123 00:07:21,610 --> 00:07:23,290 I mean, we would expect similar chemistry, 124 00:07:23,290 --> 00:07:24,930 we'd expect water, et cetera. 125 00:07:24,930 --> 00:07:27,300 It's probably tricky to get exactly the right conditions 126 00:07:27,300 --> 00:07:30,170 to get life going, so it's unlikely to be 127 00:07:30,170 --> 00:07:32,530 absolutely everywhere, but I wouldn't be surprised 128 00:07:32,530 --> 00:07:36,163 if there is other life around in our own universe. 129 00:07:37,638 --> 00:07:40,840 It would be a kind of massive freak in a way, 130 00:07:40,840 --> 00:07:42,850 {\an8}if the only place where there was life happened to be 131 00:07:42,850 --> 00:07:43,803 {\an8}here on Earth. 132 00:07:45,900 --> 00:07:49,190 The universe is infinitely large, then one of the things 133 00:07:49,190 --> 00:07:51,160 {\an8}that can happen appears to be life. 134 00:07:51,160 --> 00:07:53,630 {\an8}And so unless there's something really special about us 135 00:07:53,630 --> 00:07:55,500 and there's really no physical evidence anyway 136 00:07:55,500 --> 00:07:57,620 that we're special, then yes, intelligent life 137 00:07:57,620 --> 00:07:58,960 should exist elsewhere. 138 00:07:58,960 --> 00:08:01,860 Life perhaps more intelligent than us cam exist elsewhere. 139 00:08:04,070 --> 00:08:06,020 If it really is spatially infinite, 140 00:08:06,020 --> 00:08:09,010 then I am certain that we're not alone. 141 00:08:09,010 --> 00:08:12,090 {\an8}If it's spatially finite, I'm just almost certain 142 00:08:12,090 --> 00:08:13,413 {\an8}that we're not alone. 143 00:08:14,410 --> 00:08:15,250 Almost certain why? 144 00:08:15,250 --> 00:08:16,820 Well, for all the usual reasons. 145 00:08:16,820 --> 00:08:20,760 Because there are plenty of planets in the Goldilocks zone. 146 00:08:20,760 --> 00:08:23,300 As we start to look for the planetary bodies, 147 00:08:23,300 --> 00:08:26,050 every star we've looked at over the last decade 148 00:08:26,050 --> 00:08:27,550 has turned out to have planets around it. 149 00:08:27,550 --> 00:08:30,860 We already discovered a few relatively close stars 150 00:08:30,860 --> 00:08:34,390 that have planets roughly in the Goldilocks zone. 151 00:08:34,390 --> 00:08:35,870 And that's just from a tiny sample. 152 00:08:35,870 --> 00:08:38,930 So there must be very, very many of them in our galaxy. 153 00:08:38,930 --> 00:08:42,140 And our galaxy is only one of an incredible number 154 00:08:42,140 --> 00:08:45,558 of galaxies in the bit of the universe that we can see. 155 00:08:45,558 --> 00:08:48,391 (dramatic music) 156 00:08:54,210 --> 00:08:55,960 So if nothing else, 157 00:08:55,960 --> 00:08:59,780 the sheer size of the universe makes it hard to imagine 158 00:08:59,780 --> 00:09:04,000 that we are the only example of intelligent life to date 159 00:09:04,000 --> 00:09:07,370 and the more we improve our technology and telescopes, 160 00:09:07,370 --> 00:09:12,010 the more we can see the vastness of the universe 161 00:09:12,010 --> 00:09:15,193 has only just started to reveal itself. 162 00:09:17,922 --> 00:09:21,730 {\an8}10,000 years ago, we had Earth, we had the Sun. 163 00:09:21,730 --> 00:09:25,730 {\an8}We had other things in the sky which appear to be stars. 164 00:09:25,730 --> 00:09:28,240 We didn't realize that those stars were actually 165 00:09:28,240 --> 00:09:29,680 new solar systems. 166 00:09:29,680 --> 00:09:31,210 And nowadays we pretty much know 167 00:09:31,210 --> 00:09:34,650 that every star in the night sky has at least a planet 168 00:09:34,650 --> 00:09:35,790 and if not more. 169 00:09:35,790 --> 00:09:39,280 So if our galaxy alone has 300 billion stars, 170 00:09:39,280 --> 00:09:41,600 there's probably at least 300 billion planets. 171 00:09:41,600 --> 00:09:43,996 So there's lots of planets out there. 172 00:09:43,996 --> 00:09:46,829 (dramatic music) 173 00:09:50,680 --> 00:09:52,800 Even the finite universe that we see is vast. 174 00:09:52,800 --> 00:09:56,490 Number of stars in the sky just in our one galaxy 175 00:09:56,490 --> 00:09:58,717 is hundreds of billions. 176 00:09:58,717 --> 00:10:01,550 (dramatic music) 177 00:10:02,910 --> 00:10:05,440 But then we realize there's actually other galaxies 178 00:10:05,440 --> 00:10:07,280 that contain billions of stars. 179 00:10:07,280 --> 00:10:08,607 And those stars each have planets 180 00:10:08,607 --> 00:10:11,570 and those planets each may or may not have life. 181 00:10:13,267 --> 00:10:16,380 So then we have a large thing which we call the universe, 182 00:10:16,380 --> 00:10:19,694 which has 175 billion galaxies with all these stars 183 00:10:19,694 --> 00:10:20,870 and all these planets. 184 00:10:20,870 --> 00:10:23,703 (dramatic music) 185 00:10:27,930 --> 00:10:28,940 In the last decade, 186 00:10:28,940 --> 00:10:31,780 {\an8}we have found so many alien worlds, 187 00:10:31,780 --> 00:10:34,600 {\an8}exoplanets around other stars 188 00:10:34,600 --> 00:10:37,330 {\an8}that we can be pretty confident that on average, 189 00:10:37,330 --> 00:10:39,720 every star in the night sky has a planet. 190 00:10:39,720 --> 00:10:44,310 If you run the numbers, it's potentially four billion 191 00:10:44,310 --> 00:10:46,913 Earth-like worlds in our galaxy alone. 192 00:10:47,780 --> 00:10:52,010 So to say that ours is the only place that life has arisen 193 00:10:52,010 --> 00:10:55,500 is to take a four billion to one gamble. 194 00:10:55,500 --> 00:10:58,270 Now, those odds seem pretty, pretty steep 195 00:10:58,270 --> 00:11:01,640 and I am not a gambler, even if I were, 196 00:11:01,640 --> 00:11:03,400 I think that might be a bit of a punt, 197 00:11:03,400 --> 00:11:05,243 a bit of a stretch too far. 198 00:11:11,360 --> 00:11:13,790 One of the variables in the Drake equation 199 00:11:13,790 --> 00:11:16,770 that has given the formula a lot of criticism 200 00:11:16,770 --> 00:11:20,123 is the number of times life starts on other planets. 201 00:11:22,200 --> 00:11:25,920 I don't even have to go with infinite for life. 202 00:11:25,920 --> 00:11:30,920 I think with almost certainty that we are not alone, 203 00:11:31,300 --> 00:11:33,223 that there is life in our galaxy. 204 00:11:37,048 --> 00:11:39,150 It is a theoretical possibility 205 00:11:39,150 --> 00:11:42,040 that we are the only life in the universe. 206 00:11:42,040 --> 00:11:45,430 And we still don't know of any other life forms, 207 00:11:45,430 --> 00:11:46,953 no matter how crude. 208 00:11:51,330 --> 00:11:55,760 So is life starting on other planets a likely probability 209 00:11:55,760 --> 00:11:58,163 or an incredibly rare occurrence? 210 00:12:00,382 --> 00:12:03,215 (dramatic music) 211 00:12:09,450 --> 00:12:13,520 Recently we analyzed data from the Kepler space telescope. 212 00:12:13,520 --> 00:12:17,150 {\an8}We analyzed stellar systems that have multiple planets. 213 00:12:17,150 --> 00:12:19,970 {\an8}And we predicted how many planets 214 00:12:19,970 --> 00:12:22,810 would be in the habitable zones around other stars. 215 00:12:22,810 --> 00:12:25,720 So when you look up at night, you will see a star, 216 00:12:25,720 --> 00:12:28,520 our results tell us that this should be on average 217 00:12:28,520 --> 00:12:31,530 about two planets in the habitable zone. 218 00:12:31,530 --> 00:12:34,540 So that implies that there's a lot of real estate, 219 00:12:34,540 --> 00:12:37,140 a lot of things that are vaguely like the Earth, 220 00:12:37,140 --> 00:12:38,993 rocky planets with some water on it. 221 00:12:40,950 --> 00:12:43,040 So rocky planets with water on it 222 00:12:43,040 --> 00:12:45,500 are everywhere in the universe, everywhere, 223 00:12:45,500 --> 00:12:47,120 probably an infinite number of them. 224 00:12:47,120 --> 00:12:50,030 And the carbon and water is everywhere. 225 00:12:50,030 --> 00:12:51,217 Amino acids are everywhere. 226 00:12:51,217 --> 00:12:53,390 Matter of fact, they're falling from the sky right now 227 00:12:53,390 --> 00:12:54,730 in carbonaceous chondrites. 228 00:12:54,730 --> 00:12:56,940 So the ingredients for life are everywhere 229 00:12:56,940 --> 00:12:59,420 and not just in the origin of our Earth, 230 00:12:59,420 --> 00:13:02,060 but in the origin of all the earths, the infinite earths 231 00:13:02,060 --> 00:13:03,260 that I just referred to. 232 00:13:04,240 --> 00:13:07,470 But now comes the question, should we expect life there? 233 00:13:07,470 --> 00:13:10,160 Well, there doesn't seem to be an ingredient bottleneck, 234 00:13:10,160 --> 00:13:13,310 but maybe there's what you call a recipe bottleneck. 235 00:13:13,310 --> 00:13:16,690 Maybe there had to be some very unlikely coincidence 236 00:13:16,690 --> 00:13:18,300 of this coming into contact with this, 237 00:13:18,300 --> 00:13:20,420 and then it had to be sulfur spring going on here, 238 00:13:20,420 --> 00:13:21,480 and then you have a tide going here 239 00:13:21,480 --> 00:13:22,460 and you had to have dehydrate. 240 00:13:22,460 --> 00:13:24,160 In other words, such a complicated recipe 241 00:13:24,160 --> 00:13:26,233 in that life is very, very rare. 242 00:13:27,250 --> 00:13:30,210 And therefore we don't see any aliens 243 00:13:30,210 --> 00:13:31,760 that have conquered our galaxy. 244 00:13:37,820 --> 00:13:40,800 I think life has to exist somewhere else. 245 00:13:40,800 --> 00:13:43,450 {\an8}Now, firstly, we have to think of what life is. 246 00:13:43,450 --> 00:13:47,240 {\an8}So bacteria, plants, animals those are all life. 247 00:13:47,240 --> 00:13:50,540 I would say it it's nearly guaranteed 248 00:13:50,540 --> 00:13:52,390 that some form of life exists 249 00:13:52,390 --> 00:13:54,670 in our own solar system right now. 250 00:13:54,670 --> 00:13:57,940 If you look at Titan, the largest moon of Saturn, 251 00:13:57,940 --> 00:14:01,690 it has liquid ammonia, so it has rivers and lakes 252 00:14:01,690 --> 00:14:02,610 essentially of ammonia. 253 00:14:02,610 --> 00:14:05,010 Now we can't live off of that, but there's no reason 254 00:14:05,010 --> 00:14:07,010 you can't have something else that does. 255 00:14:08,090 --> 00:14:12,100 With Mars and the polar ice caps, I believe that we'll find 256 00:14:12,100 --> 00:14:15,620 evidence that life has existed at some point on Mars, 257 00:14:15,620 --> 00:14:18,760 well within at least a decade, if not sooner. 258 00:14:18,760 --> 00:14:22,140 So that's just our little, very, very, very, very, 259 00:14:22,140 --> 00:14:24,250 very small clump of our galaxy, 260 00:14:24,250 --> 00:14:26,383 which is just one of 175 billion. 261 00:14:27,610 --> 00:14:32,263 If you look at mathematically, it has to, has to exist. 262 00:14:35,630 --> 00:14:37,970 But how does life start? 263 00:14:37,970 --> 00:14:40,960 Some new ideas suggest that asteroids 264 00:14:40,960 --> 00:14:44,600 are like planet-seeding systems that carry the formula 265 00:14:44,600 --> 00:14:46,073 for life around the universe. 266 00:14:48,130 --> 00:14:51,340 But if that isn't the case, then chemistry evolved 267 00:14:51,340 --> 00:14:56,290 here on Earth in what has been termed the primordial soup, 268 00:14:56,290 --> 00:14:58,723 but we still don't know for certain. 269 00:14:59,660 --> 00:15:03,110 {\an8}It seems unlikely that we are very, very improbable, 270 00:15:03,110 --> 00:15:05,160 {\an8}and so the best guesses are 271 00:15:05,160 --> 00:15:08,973 that there are many other civilizations in our galaxy. 272 00:15:10,100 --> 00:15:12,410 But you get back to the question, what causes life? 273 00:15:12,410 --> 00:15:13,243 We don't know. 274 00:15:13,243 --> 00:15:14,373 We don't know how life starts. 275 00:15:15,680 --> 00:15:18,420 But we do know that life started on our Earth 276 00:15:18,420 --> 00:15:20,700 fairly soon after the Earth cooled down, 277 00:15:20,700 --> 00:15:24,880 which suggests to you either life starts fairly easily 278 00:15:25,880 --> 00:15:28,123 or else there's some divine intervention. 279 00:15:29,190 --> 00:15:31,790 Again, all bets are off there's divine intervention. 280 00:15:33,320 --> 00:15:35,220 Life seemed to start on Earth 281 00:15:35,220 --> 00:15:37,263 as soon as the Earth cooled down. 282 00:15:38,100 --> 00:15:42,193 This does suggest that life is relatively easy to start. 283 00:15:43,230 --> 00:15:45,930 But this is a sample size of one. 284 00:15:45,930 --> 00:15:48,560 Until we confirm another life form, 285 00:15:48,560 --> 00:15:50,453 we still don't know for sure. 286 00:15:51,378 --> 00:15:54,211 (dramatic music) 287 00:15:55,590 --> 00:15:58,670 {\an8}Life appears to have emerged here on Earth, 288 00:15:58,670 --> 00:16:00,910 {\an8}pretty much as soon as the conditions 289 00:16:00,910 --> 00:16:03,490 were even vaguely hospitable. 290 00:16:03,490 --> 00:16:06,420 So, if life emerged so quickly on Earth, 291 00:16:06,420 --> 00:16:08,993 maybe it is simple for it to emerge elsewhere. 292 00:16:10,760 --> 00:16:13,070 I actually think life might be 293 00:16:13,070 --> 00:16:14,810 relatively easy to kickstart, 294 00:16:14,810 --> 00:16:17,020 {\an8}because we don't know the exact mechanism 295 00:16:17,020 --> 00:16:20,250 {\an8}by which life arose, it's very difficult to put a number. 296 00:16:20,250 --> 00:16:22,400 My suspicion is it might not be as hard as we're thinking 297 00:16:22,400 --> 00:16:24,930 and potentially a lot of these habitable worlds 298 00:16:24,930 --> 00:16:26,683 could well be inhabited. 299 00:16:27,740 --> 00:16:30,410 Now whether that life can communicate, 300 00:16:30,410 --> 00:16:32,930 whether it's intelligent life, again, 301 00:16:32,930 --> 00:16:36,023 it's just unknowable until we detect it. 302 00:16:39,120 --> 00:16:42,180 One of the exciting things with astronomy at the moment 303 00:16:42,180 --> 00:16:44,620 is that we're really legitimately looking now 304 00:16:44,620 --> 00:16:46,240 for life on other planets. 305 00:16:46,240 --> 00:16:48,110 And it's something that within a decade or so, 306 00:16:48,110 --> 00:16:51,630 there's a very good chance that we might be able to measure. 307 00:16:51,630 --> 00:16:52,560 And I'm not talking about 308 00:16:52,560 --> 00:16:55,560 listening for radio signals from aliens. 309 00:16:55,560 --> 00:16:56,890 What I'm talking about is looking at 310 00:16:56,890 --> 00:17:00,500 the atmospheres of planets that exist around other stars 311 00:17:00,500 --> 00:17:03,300 and looking for traces of life in those atmospheres, 312 00:17:03,300 --> 00:17:06,150 things like oxygen, which we know is unstable. 313 00:17:06,150 --> 00:17:10,500 If you have O2 then it has to be being created by something 314 00:17:10,500 --> 00:17:14,140 because it's very unstable, it will rust, it will burn, 315 00:17:14,140 --> 00:17:16,480 and it won't hang around for long. 316 00:17:16,480 --> 00:17:19,670 So if you can see something like O2 in the atmosphere 317 00:17:19,670 --> 00:17:22,777 then something's producing it and that thing could be life. 318 00:17:22,777 --> 00:17:25,240 (dramatic music) 319 00:17:25,240 --> 00:17:27,180 Intelligent life is still 320 00:17:27,180 --> 00:17:30,640 one of the big questions for us to answer. 321 00:17:30,640 --> 00:17:34,650 As yet, all the searching we have done has only shown us 322 00:17:34,650 --> 00:17:38,663 what a vast, lonely place the universe appears to be. 323 00:17:40,150 --> 00:17:44,690 But other intelligent life could take many forms 324 00:17:44,690 --> 00:17:47,050 and looking for versions of ourselves 325 00:17:47,050 --> 00:17:49,423 could be entirely the wrong approach. 326 00:17:51,950 --> 00:17:55,530 So, we'd like to know how convergent human life is, 327 00:17:55,530 --> 00:17:58,570 {\an8}or whether we should expect humanoids on other planets. 328 00:17:58,570 --> 00:18:00,072 {\an8}For example, if there's an infinite number 329 00:18:00,072 --> 00:18:02,810 of life forms out there, what is their diversity? 330 00:18:02,810 --> 00:18:04,743 How different will they be from us? 331 00:18:06,020 --> 00:18:08,170 Some biologists think that they will be 332 00:18:08,170 --> 00:18:11,240 completely different, there's not a remote chance in hell 333 00:18:11,240 --> 00:18:13,020 of finding a humanoid out there, 334 00:18:13,020 --> 00:18:15,770 like the do every week on "Star Trek." 335 00:18:15,770 --> 00:18:17,500 Other biologists think that no, 336 00:18:17,500 --> 00:18:21,430 there are convergent features that produces humanoids 337 00:18:21,430 --> 00:18:25,270 and produce an elephantoid or produce a dogoid, 338 00:18:25,270 --> 00:18:26,710 and again, and again, and again. 339 00:18:26,710 --> 00:18:29,820 So if we go back 500 million years 340 00:18:29,820 --> 00:18:34,820 and then let it run again, we will find similar species 341 00:18:34,860 --> 00:18:36,160 again and again and again. 342 00:18:38,980 --> 00:18:41,440 Other biologists say, no, if you run the tape of life again, 343 00:18:41,440 --> 00:18:44,053 you will get very, very different things every time. 344 00:18:45,560 --> 00:18:49,520 So the branching of life is very uncertain. 345 00:18:49,520 --> 00:18:52,060 At any point, life could take a turn 346 00:18:52,060 --> 00:18:54,123 from one species to another. 347 00:18:55,030 --> 00:18:58,020 In another world, man may never have evolved 348 00:18:58,020 --> 00:18:59,683 past the ape stage. 349 00:19:00,610 --> 00:19:04,270 So what is the likelihood of another human species 350 00:19:04,270 --> 00:19:05,623 on another planet? 351 00:19:06,570 --> 00:19:08,890 How unlikely are we? 352 00:19:08,890 --> 00:19:11,180 {\an8}Are we infinitely unlikely? 353 00:19:11,180 --> 00:19:14,570 {\an8}I don't think so, but I don't know so. 354 00:19:14,570 --> 00:19:17,760 So the question is how often is there life out there? 355 00:19:17,760 --> 00:19:19,860 There's reasons to go out and look for ET, 356 00:19:20,750 --> 00:19:22,886 because that would kinda prove it. 357 00:19:22,886 --> 00:19:25,110 On the other hand, it's worthwhile contemplating 358 00:19:25,110 --> 00:19:27,600 whether or not we might be it. 359 00:19:27,600 --> 00:19:29,490 And so that is a question we can go out 360 00:19:29,490 --> 00:19:32,840 and answer by literally looking what's going on 361 00:19:32,840 --> 00:19:35,410 on other planets and seeing if there are signs of life 362 00:19:35,410 --> 00:19:38,470 and then looking out and listening and seeing if we can hear 363 00:19:38,470 --> 00:19:41,290 the moral equivalents of ourselves. 364 00:19:41,290 --> 00:19:44,680 I don't know what the likelihood is of us finding something. 365 00:19:44,680 --> 00:19:47,360 The universe is very big, it's very hard for humans 366 00:19:47,360 --> 00:19:49,080 to even find ourselves. 367 00:19:49,080 --> 00:19:53,187 We've only existed for 100,000 years on a planet, 368 00:19:53,187 --> 00:19:55,360 and so that's like in a 24-hour day, 369 00:19:55,360 --> 00:19:58,640 two seconds, in a 24-hour day. 370 00:19:58,640 --> 00:20:00,790 And of course we've only been able to send radio signals 371 00:20:00,790 --> 00:20:05,790 and receive them for 40 or 50 years to any degree at all. 372 00:20:08,050 --> 00:20:11,630 The human species is in its absolute infancy 373 00:20:11,630 --> 00:20:14,010 in terms of being able to be detected 374 00:20:14,010 --> 00:20:16,223 by other intelligent beings. 375 00:20:17,150 --> 00:20:20,980 The first signs that we existed, were our first radio 376 00:20:20,980 --> 00:20:22,130 and television signals. 377 00:20:23,900 --> 00:20:26,220 Wonderful new Westinghouse television set, 378 00:20:26,220 --> 00:20:30,340 with just one hand like this. 379 00:20:30,340 --> 00:20:32,844 Children of course loved that film. 380 00:20:32,844 --> 00:20:34,872 Hiya, Red Riding Hood, where you going? 381 00:20:34,872 --> 00:20:36,935 About the whitest white. 382 00:20:36,935 --> 00:20:39,602 (woman screams) 383 00:20:42,113 --> 00:20:47,113 ♪ Every time I see you standing there before me ♪ 384 00:20:52,870 --> 00:20:55,500 These signals have only just begun 385 00:20:55,500 --> 00:20:57,200 in the time scale of the universe. 386 00:20:59,430 --> 00:21:03,040 The first strong radio signals that humans broadcasted, 387 00:21:03,040 --> 00:21:05,680 {\an8}our first radio waves that have been going through space 388 00:21:05,680 --> 00:21:09,993 {\an8}and traveling, have only reached 11,000 stars 389 00:21:09,993 --> 00:21:13,409 and there are about 300 billion stars in our galaxy alone, 390 00:21:13,409 --> 00:21:15,233 and there's 175 billion galaxies. 391 00:21:16,240 --> 00:21:19,620 We haven't even touched a percent of a percent of a percent 392 00:21:19,620 --> 00:21:22,910 of a percent of communicating with these people. 393 00:21:22,910 --> 00:21:25,480 So even if they have just gotten a radio broadcast 394 00:21:25,480 --> 00:21:29,610 from the 1900s, they then have to return that signal back, 395 00:21:29,610 --> 00:21:31,810 so we're gonna be waiting hundreds of years. 396 00:21:33,852 --> 00:21:36,097 And this is the problem. 397 00:21:36,097 --> 00:21:38,320 The vast distances of the universe 398 00:21:38,320 --> 00:21:40,430 make it impossible to communicate 399 00:21:40,430 --> 00:21:42,573 with even our closest neighbors. 400 00:21:43,970 --> 00:21:47,490 Unless another form of communication is discovered 401 00:21:47,490 --> 00:21:50,900 then our efforts to communicate are unfortunately 402 00:21:50,900 --> 00:21:53,970 still in the science fiction realm. 403 00:21:53,970 --> 00:21:57,470 This it seems is like the ultimate tease, 404 00:21:57,470 --> 00:21:59,530 as our best science tells us 405 00:21:59,530 --> 00:22:03,333 that the universe must be full of other intelligent beings. 406 00:22:04,790 --> 00:22:07,110 The worry of course is that these things 407 00:22:07,110 --> 00:22:09,290 {\an8}are so widely separated that we'll never meet 408 00:22:09,290 --> 00:22:11,240 {\an8}these other creatures. 409 00:22:11,240 --> 00:22:14,644 {\an8}(dramatic music) 410 00:22:14,644 --> 00:22:17,210 So it might be that the universe is infinitely big, 411 00:22:17,210 --> 00:22:19,250 in which case there's gonna be lots of civilizations 412 00:22:19,250 --> 00:22:21,490 that are just far, far too far away 413 00:22:21,490 --> 00:22:22,910 to ever get in contact with us. 414 00:22:22,910 --> 00:22:26,193 You know, we'll be totally outside their light cone even. 415 00:22:28,490 --> 00:22:32,300 I see no doubt that every galaxy has at least one planet 416 00:22:32,300 --> 00:22:34,430 with intelligent life like us right now. 417 00:22:34,430 --> 00:22:37,000 So that's like 175 billion right there. 418 00:22:37,000 --> 00:22:38,080 But we're never gonna be able 419 00:22:38,080 --> 00:22:40,760 to talk to these people, unfortunately. 420 00:22:40,760 --> 00:22:42,590 The same physics that we use to figure it out 421 00:22:42,590 --> 00:22:44,970 {\an8}that they're there tells us it's gonna be too long 422 00:22:44,970 --> 00:22:46,860 {\an8}to talk to them or travel to. 423 00:22:46,860 --> 00:22:49,660 {\an8}Not to say that we can't figure out something new to do. 424 00:22:52,200 --> 00:22:55,940 But aliens may be much more advanced than us. 425 00:22:55,940 --> 00:22:57,800 They may have found a way to travel 426 00:22:57,800 --> 00:23:00,070 faster than the speed of light. 427 00:23:00,070 --> 00:23:03,623 So if they exist, why have we not heard from them? 428 00:23:05,230 --> 00:23:07,450 Is it possible that civilizations 429 00:23:07,450 --> 00:23:10,280 only exist for a short time 430 00:23:10,280 --> 00:23:13,260 and therefore finding an intelligent civilization 431 00:23:13,260 --> 00:23:16,650 in our neighborhood that is in the technological stage 432 00:23:16,650 --> 00:23:20,210 of its evolution is maybe just too rare, 433 00:23:20,210 --> 00:23:22,593 akin to finding a needle in a haystack. 434 00:23:23,970 --> 00:23:26,950 {\an8}So maybe life on this planet has actually emerged 435 00:23:26,950 --> 00:23:30,190 {\an8}at the earliest point that it could in our galaxy. 436 00:23:30,190 --> 00:23:32,650 {\an8}In which case, why haven't we heard from anybody else? 437 00:23:32,650 --> 00:23:34,750 Because they've only just started as well. 438 00:23:38,680 --> 00:23:40,660 We've only been around for two million years 439 00:23:40,660 --> 00:23:43,810 out of four, four and a half billion years on this planet. 440 00:23:43,810 --> 00:23:47,470 So lots of planets could have had life at different times 441 00:23:47,470 --> 00:23:50,620 that we have never experienced or never will experience. 442 00:23:50,620 --> 00:23:53,150 {\an8}The universe is almost 14 billion years old, 443 00:23:53,150 --> 00:23:55,730 {\an8}so you could have had advanced civilizations 444 00:23:55,730 --> 00:23:57,157 {\an8}that lived 1.3 billion years ago 445 00:23:57,157 --> 00:23:58,810 and have long disappeared. 446 00:23:58,810 --> 00:24:01,970 Maybe we'll disappear within a few hundred thousand years 447 00:24:01,970 --> 00:24:04,230 at the rate we're going, maybe much less. 448 00:24:04,230 --> 00:24:08,050 So I think life could be all through the universe, 449 00:24:08,050 --> 00:24:11,380 but for a practical person, I'd ask a different question. 450 00:24:11,380 --> 00:24:14,430 What's the likelihood that we'll ever have contact 451 00:24:14,430 --> 00:24:16,240 with another form of life? 452 00:24:16,240 --> 00:24:18,260 That's a very different question. 453 00:24:18,260 --> 00:24:21,403 And that now gets us to the finite speed of light. 454 00:24:22,273 --> 00:24:23,920 The speed of light is not infinitely fast, 455 00:24:23,920 --> 00:24:26,520 so if you were to try to communicate to anyone 456 00:24:26,520 --> 00:24:29,400 within some distance, you wouldn't get very far. 457 00:24:29,400 --> 00:24:31,540 That signal would have to travel for thousands of years 458 00:24:31,540 --> 00:24:35,050 to have much chance of making contact with intelligent life. 459 00:24:35,050 --> 00:24:37,670 So you'd have to be around a very long time, 460 00:24:37,670 --> 00:24:40,550 maybe thousands, maybe tens of thousands of years 461 00:24:40,550 --> 00:24:42,980 as an intelligent race, advanced race, 462 00:24:42,980 --> 00:24:46,280 to have any chance of contacting these other forms of life. 463 00:24:46,280 --> 00:24:47,680 So there's two questions there. 464 00:24:47,680 --> 00:24:49,440 Does life exists throughout the universe? 465 00:24:49,440 --> 00:24:51,060 I'm sure it does. 466 00:24:51,060 --> 00:24:52,560 Is the life contactable? 467 00:24:52,560 --> 00:24:54,790 Could you make contact with it and communicate with it 468 00:24:54,790 --> 00:24:59,040 in a reasonable timeframe being thousands of years? 469 00:24:59,040 --> 00:25:01,963 I think the chances are very, very small, if not zero. 470 00:25:06,010 --> 00:25:10,000 So communications seems impossible as yet. 471 00:25:10,000 --> 00:25:12,300 But what about traveling to the stars 472 00:25:12,300 --> 00:25:14,163 to discover new worlds? 473 00:25:15,540 --> 00:25:18,120 One obvious drawback to this idea 474 00:25:18,120 --> 00:25:21,600 is that our lifespan is simply too short. 475 00:25:21,600 --> 00:25:26,330 A trip to Mars, our local planet, will take four years. 476 00:25:26,330 --> 00:25:31,163 A trip to our closest star will take over 150 years. 477 00:25:32,290 --> 00:25:34,490 So again, still seems delegated 478 00:25:34,490 --> 00:25:37,550 to the science fiction realm for now. 479 00:25:37,550 --> 00:25:40,480 But anything is possible given enough time 480 00:25:40,480 --> 00:25:42,343 in an infinite universe. 481 00:25:45,260 --> 00:25:47,940 We'll probably never experience 482 00:25:47,940 --> 00:25:50,850 another intelligent life form, unfortunately. 483 00:25:50,850 --> 00:25:53,343 So I believe that intelligent life form exists. 484 00:25:54,860 --> 00:25:56,260 Maybe it doesn't look like exactly 485 00:25:56,260 --> 00:25:58,560 what we think of in the movies, but maybe it does. 486 00:25:58,560 --> 00:26:00,460 Maybe they're identical to me and you. 487 00:26:02,380 --> 00:26:04,920 So perhaps life is a common occurrence 488 00:26:04,920 --> 00:26:09,270 in the universe, but what about human life? 489 00:26:09,270 --> 00:26:10,743 How rare could it be? 490 00:26:12,410 --> 00:26:14,280 And if not human life, 491 00:26:14,280 --> 00:26:17,493 what other kinds of diverse life could exist? 492 00:26:19,410 --> 00:26:20,660 How about human-like intelligence? 493 00:26:20,660 --> 00:26:23,160 If there's all this life elsewhere, 494 00:26:23,160 --> 00:26:25,570 they would surely get intelligent, build spacecrafts, 495 00:26:25,570 --> 00:26:26,703 and then colonize the entire galaxy. 496 00:26:26,703 --> 00:26:28,850 There's been plenty of time to do that, 497 00:26:28,850 --> 00:26:31,000 but we don't see spacecraft around here, 498 00:26:31,000 --> 00:26:34,320 or we don't see alien signals when we listen 499 00:26:34,320 --> 00:26:35,750 with the radio telescopes. 500 00:26:35,750 --> 00:26:38,380 Well, that might be that maybe human-like intelligence 501 00:26:38,380 --> 00:26:41,710 is not something that is a natural part of evolution. 502 00:26:41,710 --> 00:26:44,380 There are many millions of other species on this planet 503 00:26:44,380 --> 00:26:47,140 and they are not evolving to become human-like. 504 00:26:47,140 --> 00:26:48,470 They don't wanna become human 505 00:26:48,470 --> 00:26:50,710 any more than we wanna become an elephant. 506 00:26:50,710 --> 00:26:52,340 Chimpanzees don't wanna become humans, 507 00:26:52,340 --> 00:26:53,670 humans don't wanna become chimpanzees. 508 00:26:53,670 --> 00:26:56,520 There's a relativity there, it's not human superiority. 509 00:26:56,520 --> 00:26:58,650 And so humans are not some type of 510 00:26:58,650 --> 00:27:00,120 convergent feature of evolution. 511 00:27:00,120 --> 00:27:04,210 So, that might be to explain why we don't see all of these. 512 00:27:04,210 --> 00:27:05,720 There could be life everywhere, 513 00:27:05,720 --> 00:27:07,650 but it wouldn't be space-faring, 514 00:27:07,650 --> 00:27:09,350 it wouldn't produce radio signals. 515 00:27:12,680 --> 00:27:17,090 Or maybe it does, but then it gets so fancy, 516 00:27:17,090 --> 00:27:18,940 they build all kinds of bombs, have big wars, 517 00:27:18,940 --> 00:27:20,290 and they killed themselves. 518 00:27:22,230 --> 00:27:24,160 It's the self-destruction bottleneck. 519 00:27:24,160 --> 00:27:26,890 So, there's many scenarios you can think of 520 00:27:26,890 --> 00:27:30,200 that are consistent with no visible aliens 521 00:27:30,200 --> 00:27:33,326 and lots and lots of habitable planets. 522 00:27:33,326 --> 00:27:36,159 (dramatic music) 523 00:27:39,932 --> 00:27:43,880 Two billion years ago, we literally were amoebas 524 00:27:43,880 --> 00:27:45,420 and we evolved over two billion years 525 00:27:45,420 --> 00:27:47,090 into what we are today. 526 00:27:47,090 --> 00:27:51,040 So, if you imagine that something similar happened 527 00:27:51,040 --> 00:27:52,910 on other Earth-like planets 528 00:27:52,910 --> 00:27:56,850 and they have had two billion more years to evolve, 529 00:27:56,850 --> 00:27:58,250 then they'll looking at us and they're thinking, 530 00:27:58,250 --> 00:28:01,850 hey, we're amoebas and we don't even understand 531 00:28:01,850 --> 00:28:05,040 what they are, or no hope of talking. 532 00:28:05,040 --> 00:28:06,340 You don't talk to amoebas. 533 00:28:06,340 --> 00:28:08,550 And so maybe that's the situation we're in. 534 00:28:08,550 --> 00:28:09,610 And that's why we think there's 535 00:28:09,610 --> 00:28:11,753 no other life form in the universe. 536 00:28:14,070 --> 00:28:17,120 What if life is everywhere in our universe, 537 00:28:17,120 --> 00:28:20,010 but it is so unrecognizable to us 538 00:28:20,010 --> 00:28:21,663 that we don't even realize it. 539 00:28:23,180 --> 00:28:26,870 Could life exist on such small, quantum levels 540 00:28:26,870 --> 00:28:31,720 that we can never see it, or such huge scales that again, 541 00:28:31,720 --> 00:28:33,513 we could never perceive of it. 542 00:28:35,550 --> 00:28:38,480 Is it possible that the universe is filled with aliens 543 00:28:38,480 --> 00:28:41,230 that we just don't know about because they're made out of 544 00:28:41,230 --> 00:28:44,810 dark energy for example, or they communicate with neutrinos, 545 00:28:44,810 --> 00:28:46,750 or they communicate with radio wavelengths 546 00:28:46,750 --> 00:28:49,650 that are so long that we don't know about them? 547 00:28:49,650 --> 00:28:52,290 Well, you can easily imagine that, you know, 548 00:28:52,290 --> 00:28:54,650 before 200 years ago, we didn't have radio communication. 549 00:28:54,650 --> 00:28:56,520 So imagine if the universe were filled with 550 00:28:56,520 --> 00:28:57,950 radio-communicating civilizations. 551 00:28:57,950 --> 00:29:00,930 We wouldn't even know it until we invented the radio. 552 00:29:00,930 --> 00:29:03,330 Ditto for any other technology you can think of. 553 00:29:04,776 --> 00:29:06,680 But what if we did have communication 554 00:29:06,680 --> 00:29:08,823 with another intelligent life form? 555 00:29:09,940 --> 00:29:12,230 This has been the stuff of science fiction 556 00:29:12,230 --> 00:29:14,200 for the last century. 557 00:29:14,200 --> 00:29:18,000 And in most cases, the plots portray a fear of the unknown 558 00:29:18,000 --> 00:29:20,037 and war with the aliens ensues. 559 00:29:21,497 --> 00:29:24,023 Is this indicative of our likely behavior? 560 00:29:25,050 --> 00:29:29,030 Are all aliens to be feared, or would we take a more 561 00:29:29,030 --> 00:29:31,780 intelligent, scientific approach? 562 00:29:31,780 --> 00:29:34,613 (dramatic music) 563 00:29:44,020 --> 00:29:46,100 {\an8}If they were conscious beings, then that would be 564 00:29:46,100 --> 00:29:49,210 {\an8}such a threat to humanity because we have 565 00:29:49,210 --> 00:29:52,503 this assumed ego that we are all there is. 566 00:29:53,640 --> 00:29:56,040 Anything that is unknown is a threat 567 00:29:56,040 --> 00:29:59,253 to our stable, fragile existence. 568 00:30:01,070 --> 00:30:03,490 You know, I think it would be vastly exciting 569 00:30:03,490 --> 00:30:06,290 to be able to try to understand life forms 570 00:30:06,290 --> 00:30:09,540 that were massively different to us. 571 00:30:09,540 --> 00:30:11,640 We've evolved in a very particular way, 572 00:30:11,640 --> 00:30:13,570 but other forms of life might have done 573 00:30:13,570 --> 00:30:16,240 {\an8}something totally different. 574 00:30:16,240 --> 00:30:18,090 {\an8}And that would be quite exciting 575 00:30:18,090 --> 00:30:20,293 {\an8}if we could indeed wrap our minds around it. 576 00:30:23,150 --> 00:30:25,040 It's actually very difficult to get your head around 577 00:30:25,040 --> 00:30:28,140 what the possible implications would be of discovering 578 00:30:28,140 --> 00:30:31,450 and communicating with some other sort of alien life form. 579 00:30:31,450 --> 00:30:33,830 {\an8}I think that people would be incredibly excited 580 00:30:33,830 --> 00:30:35,760 {\an8}and it would change people's way 581 00:30:35,760 --> 00:30:37,740 of thinking about their lives and their role 582 00:30:37,740 --> 00:30:39,433 in the sort of universe. 583 00:30:41,700 --> 00:30:45,130 While humans on the Earth are kind of the top predator 584 00:30:45,130 --> 00:30:48,640 and we pretty much do what we like, whenever we like, 585 00:30:48,640 --> 00:30:51,600 and there are serious consequences arising from that. 586 00:30:51,600 --> 00:30:53,200 But nevertheless, you've gotta think, 587 00:30:53,200 --> 00:30:55,020 we wouldn't be the top predator necessarily 588 00:30:55,020 --> 00:30:57,790 when we start discovering other intelligent life forms. 589 00:30:57,790 --> 00:31:00,700 And you know, it might turn out that things don't go 590 00:31:00,700 --> 00:31:02,553 entirely our way. 591 00:31:07,400 --> 00:31:10,840 The discovery of life, intelligent life, 592 00:31:10,840 --> 00:31:13,890 somewhere in our universe, our galaxy, 593 00:31:13,890 --> 00:31:16,900 would be at once the most terrifying thought 594 00:31:16,900 --> 00:31:21,900 {\an8}and yet most satisfying and relieving discovery, 595 00:31:22,810 --> 00:31:27,460 simply because the burden of keeping this unique, 596 00:31:27,460 --> 00:31:29,780 wonderful phenomenon of life 597 00:31:29,780 --> 00:31:33,150 and all of its infinite variety and possibilities 598 00:31:33,150 --> 00:31:35,320 is no longer ours alone to carry. 599 00:31:35,320 --> 00:31:37,500 An asteroid could come and wipe us out. 600 00:31:37,500 --> 00:31:40,140 The Sun will one day eventually sterilize the Earth 601 00:31:40,140 --> 00:31:42,343 by expanding towards the end of its life. 602 00:31:48,930 --> 00:31:50,440 And right now that burden is on us 603 00:31:50,440 --> 00:31:51,670 and we're doing a terrible job of it. 604 00:31:51,670 --> 00:31:53,893 We are not very good custodians of this. 605 00:31:56,040 --> 00:31:58,740 But if there were aliens out there and they were intelligent 606 00:31:58,740 --> 00:32:00,100 and they were able to spread between the stars, 607 00:32:00,100 --> 00:32:02,538 then suddenly you would think, well, I guess it's not so bad 608 00:32:02,538 --> 00:32:06,740 that us humans are kind of dropping the ball on this, 609 00:32:06,740 --> 00:32:08,570 this idea of trying to sustain life 610 00:32:08,570 --> 00:32:13,330 as a very beautifully weird and unexpected consequence 611 00:32:13,330 --> 00:32:15,780 of basic laws of physics and chemistry, 612 00:32:15,780 --> 00:32:20,360 but with infinite possibility, where the laws of physics 613 00:32:20,360 --> 00:32:23,963 are essentially boring and restrictive. 614 00:32:25,447 --> 00:32:28,540 (dramatic music) 615 00:32:28,540 --> 00:32:30,880 From a scientific point of view, 616 00:32:30,880 --> 00:32:32,770 I would want to know what their science is 617 00:32:32,770 --> 00:32:35,170 to see how theirs compares to ours. 618 00:32:35,170 --> 00:32:37,020 Do they describe electromagnetic radiation 619 00:32:37,020 --> 00:32:38,360 in the same way we do? 620 00:32:38,360 --> 00:32:40,750 {\an8}Do they know about the existence of electrons 621 00:32:40,750 --> 00:32:42,430 {\an8}or whatever, you know? 622 00:32:42,430 --> 00:32:44,663 {\an8}Is there something they're doing that we're not? 623 00:32:50,170 --> 00:32:52,060 I personally think that we've already 624 00:32:52,060 --> 00:32:56,370 detected life elsewhere and we just don't recognize it. 625 00:32:56,370 --> 00:33:00,170 And you do this by generalizing the definition of life. 626 00:33:00,170 --> 00:33:03,323 If you define life as a far from equilibrium 627 00:33:03,323 --> 00:33:06,530 dissipative structure, then you include fires 628 00:33:06,530 --> 00:33:10,623 and whirlpools and hurricanes as part of life. 629 00:33:12,020 --> 00:33:14,040 I think when we realize that we will then consider 630 00:33:14,040 --> 00:33:15,730 we've already found life, 631 00:33:15,730 --> 00:33:17,410 but that's a little bit of a mind bend, 632 00:33:17,410 --> 00:33:19,810 that's more of a mind bend than most people 633 00:33:19,810 --> 00:33:22,870 are willing to entertain, 634 00:33:22,870 --> 00:33:24,630 and so they're much more happy with thinking 635 00:33:24,630 --> 00:33:26,380 that maybe dark matter is aliens 636 00:33:26,380 --> 00:33:28,953 and that they have big brains and they talk English. 637 00:33:37,286 --> 00:33:39,410 What is life? 638 00:33:39,410 --> 00:33:42,593 This is a question that is surprisingly hard to answer. 639 00:33:43,950 --> 00:33:47,190 The definition of life has science divided, 640 00:33:47,190 --> 00:33:49,880 some going as far as suggesting the weather 641 00:33:49,880 --> 00:33:51,473 to be a form of life. 642 00:33:52,420 --> 00:33:55,320 What is the purpose of life, if there is one 643 00:33:55,320 --> 00:33:57,223 from an evolutionary point of view, 644 00:33:58,240 --> 00:34:02,283 or is life purely a by-product of random chemistry? 645 00:34:03,790 --> 00:34:07,720 I think life is that, well, you're not dead obviously, 646 00:34:07,720 --> 00:34:11,893 {\an8}but I kind of think that life is that you're breathing. 647 00:34:14,530 --> 00:34:18,633 I think that, um. 648 00:34:19,880 --> 00:34:22,570 {\an8}I dunno, that's a difficult question. 649 00:34:22,570 --> 00:34:24,150 {\an8}What is life? 650 00:34:24,150 --> 00:34:29,150 {\an8}I believe life is about being a servant to other people. 651 00:34:32,700 --> 00:34:35,520 I believe that this life on Earth is just like 652 00:34:35,520 --> 00:34:37,890 a mini reflection of what we're gonna do 653 00:34:37,890 --> 00:34:39,193 in heaven for eternity. 654 00:34:41,610 --> 00:34:43,540 {\an8}I think the meaning of life is a journey 655 00:34:43,540 --> 00:34:47,513 {\an8}that you make of that life, that gives that life meaning. 656 00:34:49,000 --> 00:34:51,550 Life matters because it's an adventure. 657 00:34:51,550 --> 00:34:55,410 For good or bad, there's always growth in life. 658 00:34:55,410 --> 00:34:58,430 {\an8}And if we're infinite beings, we're infinitely growing, 659 00:34:58,430 --> 00:35:00,630 {\an8}we're infinitely trying to have experiences 660 00:35:00,630 --> 00:35:02,823 that we benefit from. 661 00:35:05,720 --> 00:35:06,553 What is life? 662 00:35:06,553 --> 00:35:09,000 Life is something that we define here on Earth. 663 00:35:09,000 --> 00:35:10,120 It's hard to define. 664 00:35:10,120 --> 00:35:12,050 As a matter of fact, if you go to the biology department 665 00:35:12,050 --> 00:35:15,210 and ask biologists are viruses alive? 666 00:35:15,210 --> 00:35:16,740 You know, half of them will say yes 667 00:35:16,740 --> 00:35:18,200 and half of them will say no, 668 00:35:18,200 --> 00:35:20,040 and another third will say, huh. 669 00:35:20,040 --> 00:35:22,060 So we're not quite sure whether viruses are alive. 670 00:35:22,060 --> 00:35:23,810 And I take that as a warning signal, 671 00:35:23,810 --> 00:35:25,727 big red warning signals saying, 672 00:35:25,727 --> 00:35:27,630 do we really know what life is? 673 00:35:27,630 --> 00:35:29,560 'Cause if you think viruses are alive, 674 00:35:29,560 --> 00:35:32,760 then they outnumber all other lifeforms on this planet. 675 00:35:32,760 --> 00:35:34,020 And if you think they're not alive, well, 676 00:35:34,020 --> 00:35:36,280 then you're excluding the thing 677 00:35:36,280 --> 00:35:38,620 that outnumbers all other lifeforms. 678 00:35:38,620 --> 00:35:42,068 (dramatic music) 679 00:35:42,068 --> 00:35:44,080 When we think about life, we think about things 680 00:35:44,080 --> 00:35:46,390 that have properties that are kind of like us. 681 00:35:46,390 --> 00:35:48,650 So, we're very good at detecting kind of 682 00:35:48,650 --> 00:35:51,130 middle-sized, living things. 683 00:35:51,130 --> 00:35:52,580 We see elephants and we're pretty clear 684 00:35:52,580 --> 00:35:55,060 that they are kind of living things like us. 685 00:35:55,060 --> 00:35:56,850 {\an8}And then we start to learn about things 686 00:35:56,850 --> 00:35:57,990 {\an8}that are a little bit smaller. 687 00:35:57,990 --> 00:36:00,160 At some point we discover there are kind of molecules 688 00:36:00,160 --> 00:36:03,580 and bacteria, and they're a little bit more difficult 689 00:36:03,580 --> 00:36:05,230 to get your head around because they're so small 690 00:36:05,230 --> 00:36:06,950 and they're really very different from us, 691 00:36:06,950 --> 00:36:08,990 but we kind of, we manage it. 692 00:36:08,990 --> 00:36:10,720 But of course there might be things that have lives 693 00:36:10,720 --> 00:36:12,500 just so radically dissimilar to us 694 00:36:12,500 --> 00:36:13,950 that it's hard for us to even 695 00:36:13,950 --> 00:36:16,638 recognize them as having lives. 696 00:36:16,638 --> 00:36:19,471 (dramatic music) 697 00:36:21,360 --> 00:36:22,880 I'm a scientist, so I think there was 698 00:36:22,880 --> 00:36:24,960 some type of molecular evolution, 699 00:36:24,960 --> 00:36:27,600 which led to auto-catalytic processes, 700 00:36:27,600 --> 00:36:30,760 which led to replication, which led to some type of, 701 00:36:30,760 --> 00:36:32,300 hey, I'm gonna preserve myself 702 00:36:32,300 --> 00:36:35,300 and then et cetera, et cetera, Darwinian evolution. 703 00:36:35,300 --> 00:36:39,210 If you have that type of notion, then you have a way to, 704 00:36:39,210 --> 00:36:40,970 at least hand-wavingly describe 705 00:36:40,970 --> 00:36:44,610 how non-life evolved and life emerged. 706 00:36:44,610 --> 00:36:46,210 Well, here's the thing. 707 00:36:46,210 --> 00:36:49,510 Where do you grow this boundary from non-life to life? 708 00:36:49,510 --> 00:36:52,180 And if this evolved naturalistically, 709 00:36:52,180 --> 00:36:53,810 is there a boundary that we should put there 710 00:36:53,810 --> 00:36:55,280 and say, oh, this is life and this is not life. 711 00:36:55,280 --> 00:36:56,750 I think the answer is no. 712 00:36:56,750 --> 00:36:58,710 It's a little like, you know, you have a mother 713 00:36:58,710 --> 00:37:00,290 and you hold your mother's hand 714 00:37:00,290 --> 00:37:01,980 and she holds her mother's hand, 715 00:37:01,980 --> 00:37:03,306 and Richard Dawkins pointed out that 716 00:37:03,306 --> 00:37:07,520 here's this train of mothers and going into the past, 717 00:37:07,520 --> 00:37:09,890 and if you go back four billion years, 718 00:37:09,890 --> 00:37:11,770 you're essentially having one bacteria 719 00:37:11,770 --> 00:37:13,770 hold another bacteria's hand, right. 720 00:37:13,770 --> 00:37:16,230 And so the question is, well, where in this chain 721 00:37:16,230 --> 00:37:18,730 do you cut it and say, here's a human being 722 00:37:18,730 --> 00:37:20,600 and here's the pre-human being. 723 00:37:20,600 --> 00:37:22,390 Therefore, you can't put a boundary and say, 724 00:37:22,390 --> 00:37:23,560 everything on this side is life 725 00:37:23,560 --> 00:37:24,810 and everything on this is non-life. 726 00:37:24,810 --> 00:37:27,327 That's a silly idea in the light of evolution 727 00:37:27,327 --> 00:37:29,127 and I think we should get rid of it. 728 00:37:32,950 --> 00:37:36,870 Now we realize that actually the fundamental reason 729 00:37:36,870 --> 00:37:40,200 {\an8}or point for a lot of what we see around us, 730 00:37:40,200 --> 00:37:44,300 {\an8}is simply for that animal or organism 731 00:37:44,300 --> 00:37:45,450 to have more offspring. 732 00:37:46,680 --> 00:37:47,630 That's actually it. 733 00:37:51,430 --> 00:37:55,210 The meaning in life is self-replicating molecules. 734 00:37:55,210 --> 00:37:57,060 That's what life means. 735 00:37:57,060 --> 00:38:00,210 Life means molecules that managed to self-replicate, 736 00:38:00,210 --> 00:38:04,210 some subject themselves to evolutionary processes. 737 00:38:04,210 --> 00:38:05,940 I suppose that's what life is. 738 00:38:05,940 --> 00:38:09,560 Life is an incredibly complicated, chemical reaction. 739 00:38:09,560 --> 00:38:12,970 {\an8}And the fact that you and I have the experiences that we do 740 00:38:12,970 --> 00:38:15,930 {\an8}and have the lives that we do is all a massive by-product 741 00:38:15,930 --> 00:38:19,240 of that fundamental, simple thing, 742 00:38:19,240 --> 00:38:22,160 chemistry that locally creates order 743 00:38:22,160 --> 00:38:24,653 at the expense of globally creating disorder. 744 00:38:27,850 --> 00:38:31,990 Our brains are a by-product of an evolutionary pressure. 745 00:38:31,990 --> 00:38:35,200 In other words, to get smarter meant 746 00:38:35,200 --> 00:38:37,140 that you would have more babies, 747 00:38:37,140 --> 00:38:38,770 so there were more smarter babies. 748 00:38:38,770 --> 00:38:43,770 That drive has led us to these wonderful, adaptable, 749 00:38:43,820 --> 00:38:47,530 inquiring minds that have now unlocked 750 00:38:47,530 --> 00:38:49,580 so many of the mysteries of our universe. 751 00:38:52,030 --> 00:38:55,610 That to me gives a point to one's life, 752 00:38:55,610 --> 00:39:00,610 to inquire, to understand, to explore, those give meaning, 753 00:39:01,490 --> 00:39:03,570 in our interactions with our friends and our family, 754 00:39:03,570 --> 00:39:06,020 those give meaning, that gives the point of life. 755 00:39:08,440 --> 00:39:10,800 The fact that from your genes' perspective, 756 00:39:10,800 --> 00:39:12,830 they just wanna replicate, they just want 757 00:39:12,830 --> 00:39:16,320 their particular set to go on, okay, 758 00:39:16,320 --> 00:39:17,500 that's maybe the underlying drive 759 00:39:17,500 --> 00:39:19,400 and certainly is when you're a basic organism 760 00:39:19,400 --> 00:39:23,950 like a bacteria, but as humans we can do better, 761 00:39:23,950 --> 00:39:24,783 and we often do. 762 00:39:29,160 --> 00:39:30,380 If you have an infinite number 763 00:39:30,380 --> 00:39:32,700 of rocky planets that have wet, 764 00:39:32,700 --> 00:39:35,020 you could have an infinite number of lifeforms. 765 00:39:35,020 --> 00:39:37,000 The problem is we don't know what that means. 766 00:39:37,000 --> 00:39:40,390 For example, no one can predict the direction of evolution. 767 00:39:40,390 --> 00:39:42,840 Or if you go back, rewind the tape of life on Earth, 768 00:39:42,840 --> 00:39:44,450 and let's say, hey, let's rewind the tape 769 00:39:44,450 --> 00:39:45,850 and let's let it play again. 770 00:39:48,100 --> 00:39:50,430 Would you get humans or would you get any of the species 771 00:39:50,430 --> 00:39:51,390 that you see today? 772 00:39:51,390 --> 00:39:52,930 That's a big debate in biology. 773 00:39:52,930 --> 00:39:54,830 Stephen Jay Gould said, no way would you get 774 00:39:54,830 --> 00:39:57,210 anything remotely close to being a human. 775 00:39:57,210 --> 00:39:59,080 Another guy, Simon Conway Morris said, oh yes, 776 00:39:59,080 --> 00:40:01,340 you'd get some kind of humanoid because there are valleys 777 00:40:01,340 --> 00:40:04,887 in this adaption space where each species lives 778 00:40:04,887 --> 00:40:07,237 and that would do it again and again and again. 779 00:40:12,654 --> 00:40:16,200 (explosion booms) 780 00:40:16,200 --> 00:40:19,200 Our bodies are made from billions of atoms, 781 00:40:19,200 --> 00:40:22,100 which are all billions of years old. 782 00:40:22,100 --> 00:40:26,483 So the saying we are made from stardust is literally true. 783 00:40:28,480 --> 00:40:33,480 At the deepest level, we are the universe in human form. 784 00:40:36,130 --> 00:40:40,870 Ultimately life emerged out of the universe. 785 00:40:40,870 --> 00:40:45,870 And so for me, before I go to bed most nights, I sit down, 786 00:40:46,064 --> 00:40:50,210 {\an8}and we have a hot tub and I peer to the heavens. 787 00:40:50,210 --> 00:40:51,710 {\an8}And I look up at the stars. 788 00:40:51,710 --> 00:40:53,630 I look at the Milky Way. 789 00:40:53,630 --> 00:40:56,600 I look at the galaxies that orbit our own 790 00:40:56,600 --> 00:40:59,650 and I think of the dark spots between the stars, 791 00:40:59,650 --> 00:41:01,950 where there are countless galaxies. 792 00:41:01,950 --> 00:41:04,550 And I realize just how rich the universe is 793 00:41:04,550 --> 00:41:08,200 and how we are one small planet 794 00:41:08,200 --> 00:41:10,780 around one pretty ordinary star 795 00:41:10,780 --> 00:41:15,780 in one reasonably ordinary galaxy in a vast sea. 796 00:41:15,870 --> 00:41:17,870 And the fact that we're able to go through 797 00:41:17,870 --> 00:41:20,890 and contemplate and realize our place 798 00:41:20,890 --> 00:41:25,250 and how all this order works is amazing. 799 00:41:25,250 --> 00:41:28,430 It is to me the great, amazing story for humanity 800 00:41:28,430 --> 00:41:32,000 and it intersects with philosophy and art, 801 00:41:32,000 --> 00:41:33,700 just trying to come terms with it. 802 00:41:33,700 --> 00:41:35,250 That's how humans are gonna interact 803 00:41:35,250 --> 00:41:37,480 with that type of experience. 804 00:41:38,396 --> 00:41:41,229 (dramatic music)