1 00:00:00,255 --> 00:00:02,922 (upbeat music) 2 00:00:04,160 --> 00:00:06,140 We are in one of the greatest periods 3 00:00:06,140 --> 00:00:08,965 of discovery in humanity's history. 4 00:00:08,965 --> 00:00:09,910 (upbeat music) 5 00:00:09,910 --> 00:00:13,830 Finding out more about the universe than ever before. 6 00:00:13,830 --> 00:00:16,657 At a faster rate than ever before. 7 00:00:16,657 --> 00:00:18,740 (upbeat music) 8 00:00:18,740 --> 00:00:20,550 And of these discoveries, 9 00:00:20,550 --> 00:00:23,220 perhaps the most fascinating of all, 10 00:00:23,220 --> 00:00:26,750 is that there are other planets, other worlds, 11 00:00:26,750 --> 00:00:29,233 orbiting other stars far away. 12 00:00:30,280 --> 00:00:31,543 Exoplanets. 13 00:00:32,600 --> 00:00:36,090 Today we take for granted that there are exoplanets 14 00:00:36,090 --> 00:00:37,990 around other stars. 15 00:00:37,990 --> 00:00:42,227 And yet only a few decades ago, we had not seen one. 16 00:00:42,227 --> 00:00:43,060 (upbeat music) 17 00:00:43,060 --> 00:00:45,820 Finding the first done in 1995, 18 00:00:45,820 --> 00:00:47,205 I think nobody believed us. 19 00:00:47,205 --> 00:00:48,230 (laughing) 20 00:00:48,230 --> 00:00:49,599 It was too big. 21 00:00:49,599 --> 00:00:50,550 (upbeat music) 22 00:00:50,550 --> 00:00:51,383 Nobody thought 23 00:00:51,383 --> 00:00:53,980 this was even a thing worth studying. 24 00:00:53,980 --> 00:00:56,520 Back then, it was considered ridiculous 25 00:00:56,520 --> 00:00:58,430 to search for exoplanets. 26 00:00:58,430 --> 00:01:00,773 And it was definitely a taboo subject. 27 00:01:00,773 --> 00:01:02,310 (upbeat music) 28 00:01:02,310 --> 00:01:04,866 But what they found never ceases to amaze. 29 00:01:04,866 --> 00:01:06,270 (upbeat music) 30 00:01:06,270 --> 00:01:10,130 Nature didn't obey the laws that we had set for ourselves. 31 00:01:10,130 --> 00:01:11,199 And that was exciting. 32 00:01:11,199 --> 00:01:12,290 (upbeat music) 33 00:01:12,290 --> 00:01:15,960 Everything is exotic outside the solar system. 34 00:01:15,960 --> 00:01:19,480 The types of exoplanets that exist out there, 35 00:01:19,480 --> 00:01:20,410 it's really, I think, 36 00:01:20,410 --> 00:01:22,523 as far as your imagination can we reach. 37 00:01:23,460 --> 00:01:25,960 These are real places we can point to 38 00:01:25,960 --> 00:01:27,200 and say, "Yeah, this is a planet 39 00:01:27,200 --> 00:01:30,317 "that'll rain diamonds or sulfuric acid." 40 00:01:31,380 --> 00:01:35,050 But this quest has a very human face. 41 00:01:35,050 --> 00:01:36,740 In my heart, I wanna go out there 42 00:01:36,740 --> 00:01:39,170 and find the planet with oceans and continents 43 00:01:39,170 --> 00:01:40,763 and breathable air. 44 00:01:42,200 --> 00:01:43,823 A planet that just like Earth. 45 00:01:44,788 --> 00:01:47,455 (gentle music) 46 00:01:56,720 --> 00:01:57,880 Humans have always been 47 00:01:57,880 --> 00:01:59,600 fascinated by the heavens. 48 00:01:59,600 --> 00:02:02,449 And wondered, what is our place within them? 49 00:02:02,449 --> 00:02:03,660 (upbeat music) 50 00:02:03,660 --> 00:02:07,290 Since the stars rotate over our heads every night, 51 00:02:07,290 --> 00:02:10,540 it was only too easy to assume we were right in the middle 52 00:02:10,540 --> 00:02:12,233 of this never ending spectacle. 53 00:02:13,660 --> 00:02:15,730 We used to think that the Earth 54 00:02:15,730 --> 00:02:17,323 was the center of the universe, 55 00:02:18,320 --> 00:02:21,423 that the planets and the stars all revolved around Earth. 56 00:02:22,660 --> 00:02:25,040 Then in the 16 century, 57 00:02:25,040 --> 00:02:27,400 Polish polymath and Catholic canon, 58 00:02:27,400 --> 00:02:30,433 Nicolaus Copernicus upset the status quo. 59 00:02:31,520 --> 00:02:33,460 He figured that the apparent motion 60 00:02:33,460 --> 00:02:35,520 of the stars in the night sky 61 00:02:35,520 --> 00:02:39,080 was more likely due to the Earth moving, not the stars, 62 00:02:39,080 --> 00:02:41,323 which he believed were fixed in the heavens. 63 00:02:42,648 --> 00:02:45,840 Copernicus came along and had a new theory 64 00:02:45,840 --> 00:02:49,023 that the planets, including Earth, revolved around the Sun. 65 00:02:50,400 --> 00:02:52,293 And that was considered heretical. 66 00:02:53,140 --> 00:02:57,090 Suddenly humankind is no longer center stage 67 00:02:57,090 --> 00:02:59,470 and there is worse to come. 68 00:02:59,470 --> 00:03:00,900 Turned out that not even the Sun 69 00:03:00,900 --> 00:03:02,850 is in the center of everything. 70 00:03:02,850 --> 00:03:05,060 The Sun is one out of a few hundred billion stars 71 00:03:05,060 --> 00:03:07,520 orbiting the center of the Milky Way, 72 00:03:07,520 --> 00:03:09,460 which itself is just one galaxy 73 00:03:09,460 --> 00:03:13,293 out of probably a few hundred billions out there. 74 00:03:14,320 --> 00:03:15,510 Over the centuries, 75 00:03:15,510 --> 00:03:17,300 increasingly powerful telescopes 76 00:03:17,300 --> 00:03:19,130 revealed that the cosmos 77 00:03:19,130 --> 00:03:22,800 is both teaming with countless stars yet so vast 78 00:03:22,800 --> 00:03:25,233 that it is mostly empty space. 79 00:03:26,197 --> 00:03:29,447 (gentle upbeat music) 80 00:03:32,650 --> 00:03:37,210 If you shrink the Sun down to the size of a grain of salt, 81 00:03:37,210 --> 00:03:40,790 the Earth would be about two inches away from the salt grain 82 00:03:40,790 --> 00:03:43,240 and be almost microscopic, 83 00:03:43,240 --> 00:03:47,161 it'd be the size of a particle of smoke, for instance. 84 00:03:47,161 --> 00:03:48,040 (gentle music) 85 00:03:48,040 --> 00:03:50,067 And then one can ask, "Well, where do I put 86 00:03:50,067 --> 00:03:52,867 "the next salt grain, the next closest star?" 87 00:03:54,150 --> 00:03:55,960 That star, that next salt grain 88 00:03:55,960 --> 00:03:58,324 would be seven and a half miles away. 89 00:03:58,324 --> 00:04:00,991 (gentle music) 90 00:04:02,200 --> 00:04:07,200 So we are just dust grain floating out there. 91 00:04:07,850 --> 00:04:09,970 But still it might be that we are 92 00:04:09,970 --> 00:04:14,063 the only very interesting dust grain out there. 93 00:04:15,130 --> 00:04:17,065 I don't think so though. 94 00:04:17,065 --> 00:04:18,480 (gentle music) 95 00:04:18,480 --> 00:04:21,598 The thing of course that really drives all this is, 96 00:04:21,598 --> 00:04:25,262 is there life elsewhere in the universe? 97 00:04:25,262 --> 00:04:27,280 (gentle music) 98 00:04:27,280 --> 00:04:28,700 This is the fundamental question 99 00:04:28,700 --> 00:04:30,700 that we have in astronomy, are we alone? 100 00:04:31,990 --> 00:04:34,440 The sheer number of stars suggests 101 00:04:34,440 --> 00:04:39,440 that worlds like our own must exist elsewhere in the cosmos. 102 00:04:39,450 --> 00:04:41,730 But at the end of the 20 century, 103 00:04:41,730 --> 00:04:46,010 there is no evidence that exoplanets exist at all. 104 00:04:46,010 --> 00:04:48,700 And most astronomers believe that theorizing 105 00:04:48,700 --> 00:04:51,690 about exoplanets and their potential habitability 106 00:04:51,690 --> 00:04:53,493 is a pointless exercise. 107 00:04:54,590 --> 00:04:58,579 They're just too small and far away to be observed. 108 00:04:58,579 --> 00:05:00,000 (gentle music) 109 00:05:00,000 --> 00:05:04,560 In the early 1980s, we knew in our hearts philosophically 110 00:05:04,560 --> 00:05:07,230 that exoplanets must exist. 111 00:05:07,230 --> 00:05:11,063 But in astronomy evidence is king, it counts for everything. 112 00:05:12,100 --> 00:05:16,347 And until you see one, there's always a niggling doubt. 113 00:05:16,347 --> 00:05:18,050 (people speaking indistinctly) 114 00:05:18,050 --> 00:05:19,990 Exoplanets, it seems 115 00:05:19,990 --> 00:05:22,230 are an itch that can never be scratched. 116 00:05:22,230 --> 00:05:24,900 Four, three, two, go for engine start, one. 117 00:05:24,900 --> 00:05:26,440 (rocket engine roaring) 118 00:05:26,440 --> 00:05:29,810 But in 1983, a new kind of telescope 119 00:05:29,810 --> 00:05:32,453 is about to challenge those assumptions. 120 00:05:33,433 --> 00:05:35,207 (man speaking indistinctly) 121 00:05:35,207 --> 00:05:37,210 (upbeat music) 122 00:05:37,210 --> 00:05:41,000 The infrared astronomical satellite or IRAS, 123 00:05:41,000 --> 00:05:43,910 exploits new technology, sensitive to light 124 00:05:43,910 --> 00:05:45,923 beyond the range of human vision. 125 00:05:47,490 --> 00:05:50,690 It's detecting wavelengths where you're seeing heat 126 00:05:50,690 --> 00:05:52,660 as opposed to what the laypeople 127 00:05:52,660 --> 00:05:55,520 will call light, visible light. 128 00:05:55,520 --> 00:05:56,920 All objects in the universe 129 00:05:56,920 --> 00:06:00,040 emit some level of infrared radiation. 130 00:06:00,040 --> 00:06:01,740 And although it's invisible, 131 00:06:01,740 --> 00:06:03,873 we can sometimes feel it as heat. 132 00:06:03,873 --> 00:06:04,730 (upbeat music) 133 00:06:04,730 --> 00:06:08,130 We're used to the idea that with an infrared camera, 134 00:06:08,130 --> 00:06:11,610 we can see people at night while it's pitch black, 135 00:06:11,610 --> 00:06:13,640 because things that are warm 136 00:06:13,640 --> 00:06:16,623 show up by their infrared radiation. 137 00:06:18,290 --> 00:06:20,170 IRAS applies the same principle 138 00:06:20,170 --> 00:06:23,013 to its survey of the entire sky. 139 00:06:23,013 --> 00:06:25,090 (gentle music) 140 00:06:25,090 --> 00:06:28,030 Point about infrared radiation is, 141 00:06:28,030 --> 00:06:31,624 it gets to places that visible light can't. 142 00:06:31,624 --> 00:06:32,457 (laughing) 143 00:06:32,457 --> 00:06:37,457 {\an8}It can penetrate a cloud of dust around a star. 144 00:06:37,726 --> 00:06:40,393 {\an8}(gentle music) 145 00:06:41,520 --> 00:06:43,010 The space between stars 146 00:06:43,010 --> 00:06:45,490 is filled with bands of gas and dust 147 00:06:45,490 --> 00:06:48,020 that absorb and scatter visible light 148 00:06:48,020 --> 00:06:50,643 and block our view of the stars behind them. 149 00:06:52,100 --> 00:06:55,100 But the longer wavelengths of infrared radiation 150 00:06:55,100 --> 00:06:56,613 pass much more freely. 151 00:06:57,810 --> 00:07:00,170 So previously hidden stars that emit 152 00:07:00,170 --> 00:07:02,690 both visible and infrared light 153 00:07:02,690 --> 00:07:06,300 are suddenly revealed by the IRAS detector. 154 00:07:06,300 --> 00:07:10,180 Now I was working at that point on infrared technology 155 00:07:10,180 --> 00:07:12,610 for big telescopes on the ground. 156 00:07:12,610 --> 00:07:15,540 So we knew a lot about what IRAS was doing. 157 00:07:15,540 --> 00:07:19,196 And in some ways that technology was really crude. 158 00:07:19,196 --> 00:07:20,900 (gentle upbeat music) 159 00:07:20,900 --> 00:07:24,340 You just let the sky flow over the telescope, 160 00:07:24,340 --> 00:07:26,940 and then when a bright object comes up, you go bing, 161 00:07:27,850 --> 00:07:32,043 and you just map the sky bit by bit, as you drift over it. 162 00:07:33,580 --> 00:07:36,653 There were thousands, millions of new objects. 163 00:07:37,580 --> 00:07:38,987 It was a revolution. 164 00:07:38,987 --> 00:07:40,600 (gentle music) 165 00:07:40,600 --> 00:07:43,180 Around six months into the survey, 166 00:07:43,180 --> 00:07:46,220 IRAS detects a bizarre infrared signature 167 00:07:46,220 --> 00:07:51,120 from the star, Beta Pictoris, 63 light years from Earth. 168 00:07:51,120 --> 00:07:53,370 (gentle music) 169 00:07:53,370 --> 00:07:56,700 Beta Pictoris had all this extra infrared radiation 170 00:07:56,700 --> 00:07:58,610 that was unexpected. 171 00:07:58,610 --> 00:08:02,250 It wasn't part of the normal thermal spectrum, 172 00:08:02,250 --> 00:08:03,623 if I can put it that way. 173 00:08:05,530 --> 00:08:08,200 It's not coming from the star itself. 174 00:08:08,200 --> 00:08:10,613 So where is this infrared radiation coming from? 175 00:08:11,694 --> 00:08:13,580 It was a real puzzle. 176 00:08:13,580 --> 00:08:15,377 We had no idea what it was, 177 00:08:15,377 --> 00:08:18,279 and that began a big detective story in itself. 178 00:08:18,279 --> 00:08:22,050 (gentle upbeat music) 179 00:08:22,050 --> 00:08:24,420 News of the Beta Pictoris anomaly 180 00:08:24,420 --> 00:08:26,833 reaches a remote observatory and Chile, 181 00:08:28,820 --> 00:08:30,640 where two NASA astronomers 182 00:08:30,640 --> 00:08:33,400 decide to pause their survey of our solar system 183 00:08:33,400 --> 00:08:34,536 and investigate. 184 00:08:34,536 --> 00:08:35,870 (gentle upbeat music) 185 00:08:35,870 --> 00:08:38,280 We think perhaps this is a material 186 00:08:38,280 --> 00:08:40,050 which is being illuminated by the star, 187 00:08:40,050 --> 00:08:44,043 heating up and generating this excess infrared signature. 188 00:08:45,310 --> 00:08:47,360 It was a tantalizing piece of evidence 189 00:08:47,360 --> 00:08:48,710 that maybe there's something out there 190 00:08:48,710 --> 00:08:50,558 that we should be looking for. 191 00:08:50,558 --> 00:08:52,400 (gentle upbeat music) 192 00:08:52,400 --> 00:08:54,550 The telescope itself, it's on the end of a ridge, 193 00:08:54,550 --> 00:08:56,070 almost like the prow of a ship 194 00:08:56,070 --> 00:08:59,160 where the landscape falls away on three sides. 195 00:08:59,160 --> 00:09:00,260 It's rather beautiful. 196 00:09:01,490 --> 00:09:04,230 But it's also very, very dark 197 00:09:04,230 --> 00:09:06,449 and very, very clear skies. 198 00:09:06,449 --> 00:09:07,780 (gentle music) 199 00:09:07,780 --> 00:09:09,910 In spring of 1984, 200 00:09:09,910 --> 00:09:12,250 the astronomers turned their optical telescope 201 00:09:12,250 --> 00:09:14,030 towards the Milky Way. 202 00:09:14,030 --> 00:09:15,900 (gentle music) 203 00:09:15,900 --> 00:09:18,500 Beta Pictoris was a star like any other star in the sky. 204 00:09:18,500 --> 00:09:21,248 So one of thousands and thousands of stars to look at. 205 00:09:21,248 --> 00:09:22,710 (gentle music) 206 00:09:22,710 --> 00:09:23,920 But when they tried to see 207 00:09:23,920 --> 00:09:27,350 what could be causing the infrared access around the star, 208 00:09:27,350 --> 00:09:28,851 there's a problem. 209 00:09:28,851 --> 00:09:30,070 (gentle music) 210 00:09:30,070 --> 00:09:32,720 At the telescope, you really couldn't see anything. 211 00:09:33,760 --> 00:09:35,070 And that's because the central star, 212 00:09:35,070 --> 00:09:38,080 there is hundreds of millions of times brighter material 213 00:09:38,080 --> 00:09:39,064 around that star. 214 00:09:39,064 --> 00:09:40,730 (gentle music) 215 00:09:40,730 --> 00:09:41,940 Richard's only option 216 00:09:41,940 --> 00:09:44,710 is to try and blot out the light of the star 217 00:09:44,710 --> 00:09:46,680 by making a tiny Sun shield 218 00:09:46,680 --> 00:09:49,153 that astronomers called a coronagraph. 219 00:09:51,020 --> 00:09:53,523 A coronagraph is basically a way 220 00:09:53,523 --> 00:09:56,280 of putting your thumb over the star 221 00:09:56,280 --> 00:09:59,053 and being able to look at material around the star. 222 00:10:01,067 --> 00:10:02,870 Coronagraphs are usually 223 00:10:02,870 --> 00:10:04,960 precision engineered instruments, 224 00:10:04,960 --> 00:10:08,460 but Richard will need to improvise his artificial eclipse 225 00:10:08,460 --> 00:10:11,411 using supplies from the stationary cupboard. 226 00:10:11,411 --> 00:10:12,930 (gentle upbeat music) 227 00:10:12,930 --> 00:10:15,665 We use these rub-on fonts. 228 00:10:15,665 --> 00:10:18,367 (gentle upbeat music) 229 00:10:18,367 --> 00:10:22,060 We'd use the period, a half a millimeter in diameter, 230 00:10:22,060 --> 00:10:24,379 and you needed to suspend that. 231 00:10:24,379 --> 00:10:25,850 And at the very, very center of the cross, 232 00:10:25,850 --> 00:10:30,131 we would fix this tiny period, and that would be our mask. 233 00:10:30,131 --> 00:10:33,381 (gentle upbeat music) 234 00:10:35,476 --> 00:10:37,610 And suddenly, low and behold, 235 00:10:37,610 --> 00:10:40,973 when we looked at Beta Pictoris with a chronograph, wow. 236 00:10:43,610 --> 00:10:47,140 This extended disc showed up in the images. 237 00:10:47,140 --> 00:10:49,883 A flattened disc of material surrounding the star. 238 00:10:50,950 --> 00:10:54,070 What they saw looked like sort of two spikes 239 00:10:54,070 --> 00:10:55,753 sticking out on either side. 240 00:10:56,750 --> 00:10:59,900 They saw dust now, not emitting in the infrared, 241 00:10:59,900 --> 00:11:03,233 but reflecting Sunlight from the star in the center. 242 00:11:04,770 --> 00:11:07,740 This was called a debris disc. 243 00:11:07,740 --> 00:11:08,860 What they have found 244 00:11:08,860 --> 00:11:13,230 is an expansive disc of material, like the rings of Saturn, 245 00:11:13,230 --> 00:11:16,270 but on a vastly larger scale. 246 00:11:16,270 --> 00:11:19,193 It's really the fallout of the planet formation process. 247 00:11:20,370 --> 00:11:23,180 Dust created from collisions between objects 248 00:11:23,180 --> 00:11:25,944 like asteroids and rocky bodies. 249 00:11:25,944 --> 00:11:27,620 (gentle music) 250 00:11:27,620 --> 00:11:30,486 You were seeing the first evidence of extra solar planets. 251 00:11:30,486 --> 00:11:33,902 (gentle upbeat music) 252 00:11:33,902 --> 00:11:35,400 It was incredibly exciting, I mean, 253 00:11:35,400 --> 00:11:38,836 this was the first evidence of the birthplace of planets 254 00:11:38,836 --> 00:11:42,000 around other stars. 255 00:11:42,000 --> 00:11:44,230 Richard Terrile's groundbreaking image 256 00:11:44,230 --> 00:11:46,520 of the Beta Pictoris debris disc 257 00:11:46,520 --> 00:11:50,449 creates a buzz of anticipation in the astronomy underground. 258 00:11:50,449 --> 00:11:51,980 (gentle upbeat music) 259 00:11:51,980 --> 00:11:55,084 Could exoplanets be within our grasp? 260 00:11:55,084 --> 00:11:57,090 (gentle upbeat music) 261 00:11:57,090 --> 00:11:58,840 It really opened people's eyes. 262 00:11:58,840 --> 00:12:02,023 Maybe we're ready for prime time in terms of exoplanets. 263 00:12:04,950 --> 00:12:06,520 But spotting an exoplanet 264 00:12:06,520 --> 00:12:09,090 is very different from photographing a debris disc 265 00:12:09,090 --> 00:12:10,884 bigger than our solar system. 266 00:12:10,884 --> 00:12:12,360 (gentle music) 267 00:12:12,360 --> 00:12:14,540 And at decade later, exoplanets 268 00:12:14,540 --> 00:12:17,410 are still strictly a French interest. 269 00:12:17,410 --> 00:12:20,740 In the '90s, we had no exoplanets, 270 00:12:20,740 --> 00:12:22,410 nobody has found anything. 271 00:12:22,410 --> 00:12:24,743 I mean, the field did not exist at all. 272 00:12:26,160 --> 00:12:28,220 When 26-year-old Didier Queloz 273 00:12:28,220 --> 00:12:30,710 begins his PhD in astrophysics, 274 00:12:30,710 --> 00:12:33,093 he sticks to more mainstream areas. 275 00:12:34,260 --> 00:12:39,260 My supervisor, Michel Mayor, had a name on binary stars. 276 00:12:39,550 --> 00:12:41,150 That was the business he was in. 277 00:12:43,240 --> 00:12:46,860 Astronomers have been studying binary stars for decades. 278 00:12:46,860 --> 00:12:48,810 That's when two stars orbit each other. 279 00:12:49,830 --> 00:12:51,430 Binary stars are locked 280 00:12:51,430 --> 00:12:53,670 in a complex gravitational dance 281 00:12:53,670 --> 00:12:56,003 that Queloz is tasked with unraveling. 282 00:12:56,917 --> 00:12:58,660 (gentle music) 283 00:12:58,660 --> 00:13:01,350 He never imagines that his student project 284 00:13:01,350 --> 00:13:04,053 will kickstart the era of exoplanets. 285 00:13:05,710 --> 00:13:09,330 My PhD actually was to design a new equipment 286 00:13:09,330 --> 00:13:11,123 {\an8}that we called a spectrograph. 287 00:13:12,160 --> 00:13:17,060 {\an8}Precise enough to detect tiny change 288 00:13:17,060 --> 00:13:18,893 into the speed of the star. 289 00:13:20,100 --> 00:13:22,700 Subtle speed changes of a large star 290 00:13:22,700 --> 00:13:26,830 can reveal the presence of a much smaller companion star 291 00:13:26,830 --> 00:13:29,170 because the gravitational pull of the companion 292 00:13:29,170 --> 00:13:33,193 as it orbits, makes the main star appear to wobble slightly. 293 00:13:34,480 --> 00:13:36,750 The size of the wobble reflects the size 294 00:13:36,750 --> 00:13:38,153 of the companion star. 295 00:13:39,080 --> 00:13:40,910 And if there is no companion, 296 00:13:40,910 --> 00:13:44,163 then there will be no wobble in the star's position at all. 297 00:13:45,710 --> 00:13:48,840 To be able to detect the smallest stars, 298 00:13:48,840 --> 00:13:50,940 Queloz lanes to measure speed changes 299 00:13:50,940 --> 00:13:55,940 of just 50 meters per second, or 110 miles per hour, 300 00:13:56,050 --> 00:13:59,030 no mean feet and a cosmos and constant, 301 00:13:59,030 --> 00:14:00,823 violent relative motion. 302 00:14:01,950 --> 00:14:04,503 Everything is fast into space. 303 00:14:05,400 --> 00:14:08,623 Like, I mean, the motion of the Earth on its orbit, 304 00:14:10,510 --> 00:14:13,773 it's about 100,000 kilometer per hour. 305 00:14:14,850 --> 00:14:18,240 So your have to fight with all this massive change of speed. 306 00:14:18,240 --> 00:14:21,120 And you're trying to see a tiny, tiny bit. 307 00:14:21,120 --> 00:14:24,530 It is as if you want to measure the speed of a snail 308 00:14:24,530 --> 00:14:25,893 on the wing of a jet. 309 00:14:26,944 --> 00:14:29,034 (laughing) 310 00:14:29,034 --> 00:14:30,860 (jet engines roaring) 311 00:14:30,860 --> 00:14:32,570 I'm not sure the snail will survive on the wing, 312 00:14:32,570 --> 00:14:33,975 but that's about. 313 00:14:33,975 --> 00:14:37,028 (laughing) 314 00:14:37,028 --> 00:14:40,010 (gentle upbeat music) 315 00:14:40,010 --> 00:14:41,380 Queloz' spectrograph 316 00:14:41,380 --> 00:14:45,420 explores the latest advances in computers and fiber optics 317 00:14:45,420 --> 00:14:49,840 and its performance is a surprise, even to him. 318 00:14:49,840 --> 00:14:53,010 I had a goal to reach 50 meter per second, 319 00:14:53,010 --> 00:14:54,790 but I completely overshoot the goal, 320 00:14:54,790 --> 00:14:56,318 I did much better than the goal. 321 00:14:56,318 --> 00:14:57,550 (laughing) 322 00:14:57,550 --> 00:14:59,143 We ended up with 15. 323 00:15:01,080 --> 00:15:03,670 We talking about a tiny motion, which is essentially 324 00:15:03,670 --> 00:15:06,030 the speed of a running man. 325 00:15:06,030 --> 00:15:09,560 Queloz realizes that this unexpected extra sensitivity 326 00:15:09,560 --> 00:15:12,980 to changes speed, means that his spectrograph 327 00:15:12,980 --> 00:15:16,775 could now detect objects much smaller than stars. 328 00:15:16,775 --> 00:15:18,010 (gentle upbeat music) 329 00:15:18,010 --> 00:15:20,040 With this kind of accuracy, 330 00:15:20,040 --> 00:15:23,123 then you open a complete new window, which is the planet. 331 00:15:24,260 --> 00:15:26,550 But like all aspiring astronomers, 332 00:15:26,550 --> 00:15:28,837 Queloz knows that exoplanet hunting is seen 333 00:15:28,837 --> 00:15:31,993 as a disreputable occupation at best. 334 00:15:33,210 --> 00:15:35,810 Back then it was considered ridiculous 335 00:15:35,810 --> 00:15:37,630 to search for exoplanets. 336 00:15:37,630 --> 00:15:40,150 To study them at all, would've been laughable. 337 00:15:40,150 --> 00:15:43,250 And it was definitely a taboo subject. 338 00:15:43,250 --> 00:15:44,880 Making the wrong decision, 339 00:15:44,880 --> 00:15:49,120 could spell career suicide for the young astrophysicist. 340 00:15:49,120 --> 00:15:51,097 And I remember really Michel telling me, 341 00:15:51,097 --> 00:15:53,360 "Look Didier you're not going to find any planet, 342 00:15:53,360 --> 00:15:54,890 "is that okay with you?" 343 00:15:54,890 --> 00:15:58,230 And I say yes, of course, because it's so cool for me 344 00:15:58,230 --> 00:16:00,730 to demonstrate that the machine had the capability 345 00:16:01,890 --> 00:16:03,910 to detect a planet. 346 00:16:03,910 --> 00:16:06,080 In September, 1994, 347 00:16:06,080 --> 00:16:09,660 Didier Queloz begins his search for exoplanets, 348 00:16:09,660 --> 00:16:12,373 high in the mountains of Provence in France. 349 00:16:13,320 --> 00:16:17,740 Meanwhile, his PhD supervisor, goes on vacation to Hawaii, 350 00:16:17,740 --> 00:16:19,763 confident he will not be disturbed. 351 00:16:22,970 --> 00:16:25,870 Queloz has a list of 142 stars 352 00:16:25,870 --> 00:16:28,943 chosen because of their similarity to our own Sun. 353 00:16:30,140 --> 00:16:33,123 And one of these stars was 51 Peg. 354 00:16:34,290 --> 00:16:37,700 51 Pegasi is in the constellation of Pegasus 355 00:16:37,700 --> 00:16:40,606 located 48 light years from Earth. 356 00:16:40,606 --> 00:16:43,273 (gentle music) 357 00:16:44,360 --> 00:16:46,410 Queloz is looking for signs that the star 358 00:16:46,410 --> 00:16:49,840 is wobbling slightly due to the tiny gravitational pull 359 00:16:49,840 --> 00:16:53,609 of an unseen exo planet, as it orbits the star. 360 00:16:53,609 --> 00:16:56,060 (upbeat music) 361 00:16:56,060 --> 00:16:59,240 You take the light from the star and you spread it. 362 00:16:59,240 --> 00:17:01,453 You do a rainbow, what's called the spectra. 363 00:17:03,300 --> 00:17:06,390 Now, when you move the speed of the star, 364 00:17:06,390 --> 00:17:10,223 you going to change the locations of each of this line. 365 00:17:11,060 --> 00:17:13,940 In a way they become reddish or bluish. 366 00:17:13,940 --> 00:17:16,020 And it's very tiny motions, 367 00:17:16,020 --> 00:17:18,420 and you're trying to measure that, 368 00:17:18,420 --> 00:17:20,720 to build up a single point of data, 369 00:17:20,720 --> 00:17:21,978 which is the radial velocity. 370 00:17:21,978 --> 00:17:23,670 (upbeat music) 371 00:17:23,670 --> 00:17:25,290 The tug of an exoplanet 372 00:17:25,290 --> 00:17:27,690 would cause changes in the star's speed 373 00:17:27,690 --> 00:17:30,043 comparable to that of an Olympic runner. 374 00:17:31,110 --> 00:17:35,684 But immediately 51 Pegasi makes Queloz question is methods. 375 00:17:35,684 --> 00:17:39,150 (upbeat music) 376 00:17:39,150 --> 00:17:42,340 I really kind of panicked when I got the first data, 377 00:17:42,340 --> 00:17:45,003 because I think there is a bug in my software. 378 00:17:46,080 --> 00:17:48,030 The problem is that the measurements 379 00:17:48,030 --> 00:17:49,853 seem too good to be true. 380 00:17:51,360 --> 00:17:53,680 The data were telling me a story 381 00:17:53,680 --> 00:17:56,100 that was pointing to a planet, 382 00:17:56,100 --> 00:17:58,803 while I want that star to behave normally. 383 00:18:00,251 --> 00:18:02,500 And I'm trying to debunk the data 384 00:18:02,500 --> 00:18:04,750 and go back to the software, 385 00:18:04,750 --> 00:18:08,190 until I think to myself, I try all I could, 386 00:18:08,190 --> 00:18:09,743 so it must be real. 387 00:18:10,820 --> 00:18:12,460 It must be a planet, it must be a planet. 388 00:18:12,460 --> 00:18:15,060 It's unbelievable, it's unbelievable. 389 00:18:15,060 --> 00:18:17,577 And then I send this fax to Michel, 390 00:18:17,577 --> 00:18:19,462 "I think I'll find a planet." 391 00:18:19,462 --> 00:18:22,180 (upbeat music) 392 00:18:22,180 --> 00:18:23,840 This is a half Jupiter mass 393 00:18:23,840 --> 00:18:26,020 with the four and a half day periods. 394 00:18:26,020 --> 00:18:28,453 And that was what came up out of the data. 395 00:18:29,640 --> 00:18:32,510 I said to Michel, the distance of the orbiting body 396 00:18:32,510 --> 00:18:35,090 is 20 times closer to the distance 397 00:18:35,090 --> 00:18:36,590 between the Earth and the Sun. 398 00:18:37,460 --> 00:18:38,913 So the planet's very hot. 399 00:18:40,690 --> 00:18:43,190 After checking and rechecking the data, 400 00:18:43,190 --> 00:18:46,480 in October, 1995, the first exoplanet 401 00:18:46,480 --> 00:18:48,883 around a Sun-like star is announced. 402 00:18:50,060 --> 00:18:51,940 Well, we went live with that. 403 00:18:51,940 --> 00:18:54,232 And I think nobody believed us. 404 00:18:54,232 --> 00:18:55,530 (laughing) 405 00:18:55,530 --> 00:18:57,620 (gentle upbeat music) 406 00:18:57,620 --> 00:18:58,520 I remember this time 407 00:18:58,520 --> 00:19:00,420 because I was in graduate school at the time. 408 00:19:00,420 --> 00:19:03,679 And it was just wow, like so, so crazy. 409 00:19:03,679 --> 00:19:06,700 (upbeat music) 410 00:19:06,700 --> 00:19:08,280 And the reason this was so crazy 411 00:19:08,280 --> 00:19:12,100 is our Jupiter takes years to go around the Sun. 412 00:19:12,100 --> 00:19:15,423 But this planet orbits its star in a few days. 413 00:19:16,730 --> 00:19:19,170 Not only did we definitely not have gas giants, 414 00:19:19,170 --> 00:19:20,920 so close to our own Sun, 415 00:19:20,920 --> 00:19:23,343 we didn't think planets could even form there. 416 00:19:24,490 --> 00:19:28,963 How do you get a planet like that, so close to its star? 417 00:19:30,210 --> 00:19:32,610 The accepted theory of planet formation 418 00:19:32,610 --> 00:19:35,840 has gas giants forming only in the cold outer reaches 419 00:19:35,840 --> 00:19:37,283 of planetary systems. 420 00:19:38,720 --> 00:19:43,070 Assuming this new found signal was a planet, 421 00:19:43,070 --> 00:19:45,093 it would have to have broken all rules. 422 00:19:46,490 --> 00:19:48,370 The planet would've had to form somewhere else, 423 00:19:48,370 --> 00:19:49,911 far out from the star. 424 00:19:49,911 --> 00:19:51,600 (gentle upbeat music) 425 00:19:51,600 --> 00:19:53,550 And it would've had to migrate, 426 00:19:53,550 --> 00:19:55,770 would've interact with the gas 427 00:19:55,770 --> 00:19:59,859 or with other planets in the system and move inwards. 428 00:19:59,859 --> 00:20:02,240 (gentle upbeat music) 429 00:20:02,240 --> 00:20:04,860 That means that big planet came orbiting in 430 00:20:04,860 --> 00:20:07,900 destroyed all the small planets in its path. 431 00:20:07,900 --> 00:20:09,690 That shouldn't happen. 432 00:20:09,690 --> 00:20:12,240 That meant our solar system was quite different 433 00:20:12,240 --> 00:20:14,150 from what they were finding. 434 00:20:14,150 --> 00:20:15,740 (gentle upbeat music) 435 00:20:15,740 --> 00:20:17,530 And that was a tough pill to swallow for us, 436 00:20:17,530 --> 00:20:19,077 for many people. 437 00:20:20,290 --> 00:20:22,800 The community was absolutely convinced 438 00:20:22,800 --> 00:20:25,880 a planet, like Jupiter, can only be there. 439 00:20:25,880 --> 00:20:28,013 So you have to imagine that you are coming up 440 00:20:28,013 --> 00:20:31,100 with the first planet ever on orbiting a star, 441 00:20:31,100 --> 00:20:33,000 which is already a world premier, 442 00:20:33,000 --> 00:20:34,720 but the planet to come up with, 443 00:20:34,720 --> 00:20:36,930 it's not at all the one you expect. 444 00:20:36,930 --> 00:20:40,203 I mean, it was impossible to swallow, it was too big. 445 00:20:41,480 --> 00:20:43,940 But resistance is futile 446 00:20:43,940 --> 00:20:45,950 when Queloz' breakthrough technique 447 00:20:45,950 --> 00:20:48,530 leads to the discovery of a handful more, 448 00:20:48,530 --> 00:20:50,400 close-orbiting gas giants. 449 00:20:50,400 --> 00:20:54,390 In the following months, his achievement is undeniable 450 00:20:54,390 --> 00:20:57,873 and hot Jupiters become a new category of planetary body. 451 00:20:59,640 --> 00:21:03,960 Finding 51 Peg, in 1995, we kicked the door open. 452 00:21:03,960 --> 00:21:06,540 At that time, I was very proud 453 00:21:06,540 --> 00:21:09,380 to demonstrate the machine would do it, 454 00:21:09,380 --> 00:21:10,940 I mean, eventually. 455 00:21:10,940 --> 00:21:12,730 Well I was very far to realize 456 00:21:12,730 --> 00:21:16,260 it eventually turned out to be only six months. 457 00:21:16,260 --> 00:21:17,984 Really this what happened. 458 00:21:17,984 --> 00:21:18,962 (laughing) 459 00:21:18,962 --> 00:21:21,500 (gentle upbeat music) 460 00:21:21,500 --> 00:21:25,627 That moment in the mid '90s was when everything changed. 461 00:21:25,627 --> 00:21:26,980 (gentle music) 462 00:21:26,980 --> 00:21:29,540 Nature, didn't obey the laws 463 00:21:29,540 --> 00:21:31,360 that we had set for ourselves. 464 00:21:31,360 --> 00:21:32,460 And that was exciting. 465 00:21:33,630 --> 00:21:36,991 51 Pegasi b really tilted over our perspective 466 00:21:36,991 --> 00:21:41,991 of the solar system as just one possible realization 467 00:21:42,560 --> 00:21:44,283 of what can actually happen. 468 00:21:45,780 --> 00:21:48,890 But 51 Pegasi b, also triggers 469 00:21:48,890 --> 00:21:50,323 a more basic instinct. 470 00:21:51,370 --> 00:21:54,630 The main reaction that we had from the public 471 00:21:54,630 --> 00:21:57,347 and from the media, was to ask right away, 472 00:21:57,347 --> 00:21:59,175 "Is that life on that planet?" 473 00:21:59,175 --> 00:22:00,750 (gentle music) 474 00:22:00,750 --> 00:22:02,590 The idea of life is so profoundly 475 00:22:02,590 --> 00:22:04,700 connected into the society, 476 00:22:04,700 --> 00:22:06,950 then as soon as there is a little bit of a hint, 477 00:22:06,950 --> 00:22:09,335 then you start to ignite the fire. 478 00:22:09,335 --> 00:22:10,940 (gentle upbeat music) 479 00:22:10,940 --> 00:22:13,300 Inspired by 51 Pegasi, 480 00:22:13,300 --> 00:22:16,320 another young astrophysicist decides to tackle 481 00:22:16,320 --> 00:22:17,850 the formidable challenge 482 00:22:17,850 --> 00:22:20,980 of searching for life on exoplanets. 483 00:22:20,980 --> 00:22:22,200 I just love imagining 484 00:22:22,200 --> 00:22:24,830 that there's some kind of life out there. 485 00:22:24,830 --> 00:22:28,150 In my heart, I wanna go out there and find the planet 486 00:22:28,150 --> 00:22:29,700 that's just like Earth, 487 00:22:29,700 --> 00:22:33,800 with oceans and continents and breathable air, 488 00:22:33,800 --> 00:22:35,636 a planet around a Sun-like star. 489 00:22:35,636 --> 00:22:37,270 (gentle music) 490 00:22:37,270 --> 00:22:39,290 Sara focuses on the idea 491 00:22:39,290 --> 00:22:41,850 that the atmospheres of exoplanets 492 00:22:41,850 --> 00:22:44,853 could contain clues to biological processes. 493 00:22:45,990 --> 00:22:50,040 The search for life by way of gases in an atmosphere, 494 00:22:50,040 --> 00:22:53,163 this idea has been around for nearly a century. 495 00:22:54,500 --> 00:22:56,630 Our atmosphere here on Earth has oxygen, 496 00:22:56,630 --> 00:22:59,740 which fills our atmosphere to 20% by volume, 497 00:22:59,740 --> 00:23:03,633 is only here because of plants and photosynthetic bacteria. 498 00:23:04,520 --> 00:23:07,743 And without those who continuously replenish oxygen, 499 00:23:08,610 --> 00:23:10,810 our Earth's atmosphere would have no oxygen. 500 00:23:11,720 --> 00:23:14,360 The idea that an exoplanet atmosphere 501 00:23:14,360 --> 00:23:17,393 might carry the fingerprints of any life, is attractive. 502 00:23:18,440 --> 00:23:20,500 But putting that theory into practice 503 00:23:20,500 --> 00:23:22,213 has a major stumbling block. 504 00:23:24,840 --> 00:23:26,170 Well, that time we didn't know 505 00:23:26,170 --> 00:23:29,004 if we could detect exoplanet atmospheres. 506 00:23:29,004 --> 00:23:30,640 (gentle music) 507 00:23:30,640 --> 00:23:34,020 The astronomy community wanted to know why are we bothering? 508 00:23:34,020 --> 00:23:36,470 We can barely detect the planets, 509 00:23:36,470 --> 00:23:38,334 why are we studying the atmospheres? 510 00:23:38,334 --> 00:23:40,580 (gentle upbeat music) 511 00:23:40,580 --> 00:23:43,100 A breakthrough comes in 1999 512 00:23:43,100 --> 00:23:44,950 when a hot Jupiter is detected, 513 00:23:44,950 --> 00:23:47,439 as it crosses the face of its star. 514 00:23:47,439 --> 00:23:49,830 (gentle upbeat music) 515 00:23:49,830 --> 00:23:50,890 The method involves 516 00:23:50,890 --> 00:23:54,283 measuring the dip in intensity of starlight as it transits. 517 00:23:55,510 --> 00:23:59,080 And suggests an intriguing possibility, 518 00:23:59,080 --> 00:24:01,610 could the atmosphere of a transiting planet 519 00:24:01,610 --> 00:24:03,962 leave its mark on that starlight? 520 00:24:03,962 --> 00:24:05,470 (gentle upbeat music) 521 00:24:05,470 --> 00:24:08,410 My prediction was that gases in the planet atmosphere, 522 00:24:08,410 --> 00:24:11,093 or their signature, gets imprinted on the starlight. 523 00:24:12,430 --> 00:24:14,430 The molecules in the atmosphere 524 00:24:14,430 --> 00:24:17,200 should absorb certain wavelengths of starlight 525 00:24:17,200 --> 00:24:21,930 as it passes through, leaving telltale gaps in the spectrum. 526 00:24:21,930 --> 00:24:25,220 And by comparing the star when it's by itself 527 00:24:25,220 --> 00:24:27,090 to when the planet's in front of the star 528 00:24:27,090 --> 00:24:28,890 then we can then pick out what gases 529 00:24:28,890 --> 00:24:30,557 are in the planet atmosphere. 530 00:24:30,557 --> 00:24:33,230 (gentle upbeat music) 531 00:24:33,230 --> 00:24:35,060 It's not as straightforward as it sounds 532 00:24:35,060 --> 00:24:37,779 because the signal of the atmosphere is tiny. 533 00:24:37,779 --> 00:24:39,830 (gentle upbeat music) 534 00:24:39,830 --> 00:24:42,410 Think of the atmosphere like the skin of an onion 535 00:24:43,517 --> 00:24:48,517 and that whole onion in front of a giant, glowing backdrop. 536 00:24:48,614 --> 00:24:51,960 (gentle music) 537 00:24:51,960 --> 00:24:54,250 After years working on her theory, 538 00:24:54,250 --> 00:24:58,490 Sara finally proves the skeptics wrong in 2001, 539 00:24:58,490 --> 00:25:00,640 when the element sodium is detected 540 00:25:00,640 --> 00:25:04,883 in the clouds of a gas giant, 159 light years from Earth. 541 00:25:06,720 --> 00:25:09,300 Using my prediction, and it was the first time ever 542 00:25:09,300 --> 00:25:10,720 that an exoplanet atmosphere 543 00:25:10,720 --> 00:25:13,113 had been observed and identified. 544 00:25:15,110 --> 00:25:17,346 And that was just a wow moment. 545 00:25:17,346 --> 00:25:19,140 (gentle music) 546 00:25:19,140 --> 00:25:20,910 Sodium is quickly followed 547 00:25:20,910 --> 00:25:24,053 by other elements and molecules, including water, 548 00:25:24,950 --> 00:25:28,000 suggesting a tantalizing possibility, 549 00:25:28,000 --> 00:25:31,189 could a hot Jupiter host living organisms? 550 00:25:31,189 --> 00:25:33,120 (gentle music) 551 00:25:33,120 --> 00:25:35,320 All life as we know it needs liquid water. 552 00:25:36,460 --> 00:25:41,250 But the hot Jupiters, they're way too hot for water clouds. 553 00:25:41,250 --> 00:25:43,680 (gentle music) 554 00:25:43,680 --> 00:25:45,750 So close to its star, 555 00:25:45,750 --> 00:25:47,290 that means its surface temperature 556 00:25:47,290 --> 00:25:50,293 is probably above a thousand degrees Celsius. 557 00:25:52,650 --> 00:25:55,710 So there is water in hot Jupiter atmospheres, 558 00:25:55,710 --> 00:25:58,653 but it's just way too hot for liquid water. 559 00:26:00,110 --> 00:26:01,820 Which means there's no chance 560 00:26:01,820 --> 00:26:03,720 that there is life in the first place. 561 00:26:05,250 --> 00:26:08,263 Hot Jupiters are both exotic and deadly. 562 00:26:09,110 --> 00:26:11,971 But are they typical of all exoplanets? 563 00:26:11,971 --> 00:26:14,134 (gentle music) 564 00:26:14,134 --> 00:26:17,930 In the early 2000s, we definitely had a skewed view 565 00:26:17,930 --> 00:26:20,570 of planets and planetary systems. 566 00:26:20,570 --> 00:26:22,930 We could only find big planets, 567 00:26:22,930 --> 00:26:24,493 big planets close to the star. 568 00:26:25,500 --> 00:26:28,720 Gas giants like 51 Pegasi b were found 569 00:26:28,720 --> 00:26:31,673 because of their gravitational influence on their star, 570 00:26:32,640 --> 00:26:36,400 a method that works best for spotting, very large exoplanets 571 00:26:36,400 --> 00:26:38,570 in very tight orbits, 572 00:26:38,570 --> 00:26:42,170 and misses any small, rocky Earth-like worlds, 573 00:26:42,170 --> 00:26:44,095 if they exist at all. 574 00:26:44,095 --> 00:26:46,110 (gentle music) 575 00:26:46,110 --> 00:26:48,660 Hot Jupiters, they're interesting. 576 00:26:48,660 --> 00:26:49,493 But if you're saying, 577 00:26:49,493 --> 00:26:52,240 "I want to know about life and a galaxy." 578 00:26:52,240 --> 00:26:55,223 It is not the information you seek. 579 00:26:56,930 --> 00:26:58,330 The search for exoplanets 580 00:26:58,330 --> 00:27:01,763 capable of sustaining life will need a different approach. 581 00:27:03,550 --> 00:27:07,620 T-minus 10, nine, eight, seven, 582 00:27:07,620 --> 00:27:10,753 {\an8}six, five, four, three. 583 00:27:10,753 --> 00:27:13,226 Oh, oh my God. 584 00:27:13,226 --> 00:27:14,810 I can't believe it. 585 00:27:14,810 --> 00:27:16,030 (people laughing) 586 00:27:16,030 --> 00:27:19,180 In 2009, the Kepler space telescope 587 00:27:19,180 --> 00:27:20,883 launches from Cape Canaveral. 588 00:27:22,260 --> 00:27:24,140 (people laughing) 589 00:27:24,140 --> 00:27:27,570 Kepler was just a little, little, tiny mission 590 00:27:27,570 --> 00:27:29,677 that pokes its nose into the galaxy and says, 591 00:27:29,677 --> 00:27:30,957 "What's out there?" 592 00:27:31,887 --> 00:27:32,730 (gentle upbeat music) 593 00:27:32,730 --> 00:27:35,120 The Kepler mission is a sky survey 594 00:27:35,120 --> 00:27:37,810 dedicated to finding Earth-like exoplanets 595 00:27:37,810 --> 00:27:40,080 around Sun-like stars 596 00:27:40,080 --> 00:27:44,094 and is the brainchild of NASA scientist, Bill Borucki. 597 00:27:44,094 --> 00:27:45,170 (gentle upbeat music) 598 00:27:45,170 --> 00:27:46,510 We want to go into space. 599 00:27:46,510 --> 00:27:48,763 We wanna explore the stars. 600 00:27:49,690 --> 00:27:53,120 Finding the extent of intelligence in any universe. 601 00:27:53,120 --> 00:27:57,920 The only way you can do that is to prove ahead of time 602 00:27:57,920 --> 00:28:00,440 that most stars have planets. 603 00:28:00,440 --> 00:28:02,090 If there are no planets out there, 604 00:28:02,090 --> 00:28:03,335 there's no life out there. 605 00:28:03,335 --> 00:28:05,060 (gentle music) 606 00:28:05,060 --> 00:28:08,050 Borucki's plan is to detect small exoplanets 607 00:28:08,050 --> 00:28:10,320 as they transit their star, 608 00:28:10,320 --> 00:28:13,403 not individually, but on an incredible scale. 609 00:28:15,330 --> 00:28:18,570 The mission concept was to have a wide field of view, 610 00:28:18,570 --> 00:28:20,453 to observe many, many stars. 611 00:28:21,990 --> 00:28:24,402 A hundred thousand stars at one time. 612 00:28:24,402 --> 00:28:27,652 (gentle upbeat music) 613 00:28:28,940 --> 00:28:30,970 The technological challenge 614 00:28:30,970 --> 00:28:34,020 was to be able to detect minute changes. 615 00:28:34,020 --> 00:28:39,020 And by minute, I mean one part in a hundred thousand dip 616 00:28:39,760 --> 00:28:43,513 in the light of a star as the planet crossed in front of it. 617 00:28:44,880 --> 00:28:48,190 And can it do that all the way across 618 00:28:48,190 --> 00:28:50,924 that field of a hundred thousand stars? 619 00:28:50,924 --> 00:28:53,320 (gentle upbeat music) 620 00:28:53,320 --> 00:28:55,830 Bill first pitched his scheme to NASA 621 00:28:55,830 --> 00:28:58,900 in the 1980s, when technology had little chance 622 00:28:58,900 --> 00:29:00,193 of meeting the challenge. 623 00:29:01,062 --> 00:29:02,290 (gentle upbeat music) 624 00:29:02,290 --> 00:29:06,130 When Bill Borucki first proposed this crazy technique 625 00:29:06,130 --> 00:29:08,510 of looking for transits, 626 00:29:08,510 --> 00:29:10,560 I think it wasn't really taken seriously. 627 00:29:12,030 --> 00:29:15,880 In 1983, I used to walk into NASA headquarters 628 00:29:15,880 --> 00:29:18,640 telling them they had to fund this mission. 629 00:29:18,640 --> 00:29:20,220 And they would hide in their office, 630 00:29:20,220 --> 00:29:21,800 they would hide under their desks 631 00:29:21,800 --> 00:29:23,250 'cause I would harangue them. 632 00:29:25,080 --> 00:29:28,220 I have to say that Bill Borucki 633 00:29:28,220 --> 00:29:30,260 was one of the most tenacious 634 00:29:30,260 --> 00:29:33,340 and dedicated scientists I've come across. 635 00:29:33,340 --> 00:29:34,950 If you're in the space game, 636 00:29:34,950 --> 00:29:37,427 you've gotta be prepared for the long haul. 637 00:29:37,427 --> 00:29:38,860 (gentle upbeat music) 638 00:29:38,860 --> 00:29:43,430 But NASA was never gonna invest four or $500 million 639 00:29:43,430 --> 00:29:47,163 in a mission unless they knew for sure that this would work. 640 00:29:50,450 --> 00:29:54,320 The discovery of 51 Pegasi b in 1995, 641 00:29:54,320 --> 00:29:57,899 encourages NASA to take a chance with Bill's mission. 642 00:29:57,899 --> 00:29:59,550 (gentle music) 643 00:29:59,550 --> 00:30:02,390 Up to this point, people had speculated 644 00:30:02,390 --> 00:30:04,080 that there were planets around other stars, 645 00:30:04,080 --> 00:30:06,353 but no one had any empirical proof. 646 00:30:08,000 --> 00:30:10,880 The fact that there was a detection 647 00:30:11,760 --> 00:30:14,166 added scientific credibility. 648 00:30:14,166 --> 00:30:15,830 (gentle music) 649 00:30:15,830 --> 00:30:19,010 25 years after Bill conceived his mission, 650 00:30:19,010 --> 00:30:22,823 Kepler's search for Earth-like exoplanet is ready to begin. 651 00:30:24,258 --> 00:30:26,925 (gentle music) 652 00:30:28,740 --> 00:30:30,920 Far above the Earth's atmosphere, 653 00:30:30,920 --> 00:30:34,800 the telescope will enjoy a clear view of the Milky Way 654 00:30:34,800 --> 00:30:37,593 that ground-based astronomers can only dream of. 655 00:30:39,920 --> 00:30:42,270 Ambitious or foolhardy, 656 00:30:42,270 --> 00:30:44,403 nothing like it has been tried before. 657 00:30:45,580 --> 00:30:47,970 But finally, we look at the stars 658 00:30:48,900 --> 00:30:52,083 and there are 10s of billions of stars shining. 659 00:30:53,170 --> 00:30:54,691 It's beautiful. 660 00:30:54,691 --> 00:30:57,150 (upbeat music) 661 00:30:57,150 --> 00:30:59,330 And within a few hours, the data shows 662 00:30:59,330 --> 00:31:03,350 that one of the stars that we know has a planet, 663 00:31:03,350 --> 00:31:04,798 shows a transit. 664 00:31:04,798 --> 00:31:06,140 (upbeat music) 665 00:31:06,140 --> 00:31:07,230 The exoplanet 666 00:31:07,230 --> 00:31:10,593 is an incredible 750 light years from Earth. 667 00:31:11,500 --> 00:31:15,080 And Kepler passes its first test. 668 00:31:15,080 --> 00:31:17,573 And that told us this instrument's working. 669 00:31:18,430 --> 00:31:20,400 And we were so delighted. 670 00:31:20,400 --> 00:31:22,193 Just ecstatic. 671 00:31:25,390 --> 00:31:27,820 Finding an exoplanet you already know about 672 00:31:27,820 --> 00:31:29,160 is one thing, 673 00:31:29,160 --> 00:31:32,519 but Bill's sky survey is a huge gamble. 674 00:31:32,519 --> 00:31:33,800 (gentle music) 675 00:31:33,800 --> 00:31:35,610 Transit technique only works 676 00:31:35,610 --> 00:31:38,910 when that planet is rotating in exactly the same plane 677 00:31:38,910 --> 00:31:40,150 that you're looking at. 678 00:31:40,150 --> 00:31:44,223 You're basically eliminating 99% of the stars. 679 00:31:45,430 --> 00:31:49,090 But even so there were so many stars with planets 680 00:31:49,090 --> 00:31:50,770 that the transit technique 681 00:31:50,770 --> 00:31:52,783 was just finding dozens and dozens. 682 00:31:54,230 --> 00:31:56,910 All it does is take picture, after picture, after picture, 683 00:31:56,910 --> 00:32:00,130 every six seconds, the same field of view, the same stars. 684 00:32:00,130 --> 00:32:03,010 It's designed to be the most boring mission 685 00:32:03,010 --> 00:32:04,605 that has ever built. 686 00:32:04,605 --> 00:32:06,340 (gentle music) 687 00:32:06,340 --> 00:32:08,290 At the core of the Kepler mission 688 00:32:08,290 --> 00:32:11,270 is Bill's desire to find Earth-like planets 689 00:32:11,270 --> 00:32:13,732 in the habitable zone of their star. 690 00:32:13,732 --> 00:32:15,580 (gentle music) 691 00:32:15,580 --> 00:32:18,400 Also known as the Goldilocks Zone, 692 00:32:18,400 --> 00:32:21,900 this is the region that is neither too hot nor too cold 693 00:32:21,900 --> 00:32:23,530 for liquid water. 694 00:32:23,530 --> 00:32:26,460 Where life, as we know it, can thrive. 695 00:32:26,460 --> 00:32:29,050 The mission was tuned very, very carefully, 696 00:32:29,050 --> 00:32:31,740 Earth-like planets in the habitable zone, 697 00:32:31,740 --> 00:32:34,233 where water could exist on the surface. 698 00:32:35,470 --> 00:32:38,270 Kepler needs to observe three or four transits 699 00:32:38,270 --> 00:32:40,770 to confirm an exoplanet detection, 700 00:32:40,770 --> 00:32:43,180 so needs to last three or four years 701 00:32:43,180 --> 00:32:44,943 to catch Earth-like orbits. 702 00:32:46,000 --> 00:32:48,770 The whole thing was so fundamental and groundbreaking 703 00:32:48,770 --> 00:32:51,910 because Bill's not just detecting planets, 704 00:32:51,910 --> 00:32:54,740 but then finding the subset of planets 705 00:32:54,740 --> 00:32:56,740 that were in the habitable zone, 706 00:32:56,740 --> 00:32:59,485 where life might have appeared. 707 00:32:59,485 --> 00:33:03,299 (gentle upbeat music) 708 00:33:03,299 --> 00:33:05,580 In the lobbies of our main administrative building, 709 00:33:05,580 --> 00:33:07,610 we had a chart which had indicators, 710 00:33:07,610 --> 00:33:10,490 which would show you how many exoplanets were discovered, 711 00:33:10,490 --> 00:33:13,390 how many exoplanets were discovered in the habitable zone. 712 00:33:14,610 --> 00:33:15,990 These numbers would grow and grow and grow, 713 00:33:15,990 --> 00:33:16,950 and we'd suddenly discover 714 00:33:16,950 --> 00:33:18,380 that we didn't have enough digits 715 00:33:18,380 --> 00:33:21,414 to encompass all the planets that were being discovered. 716 00:33:21,414 --> 00:33:25,350 (gentle upbeat music) 717 00:33:25,350 --> 00:33:27,640 We're here today to announce new discoveries 718 00:33:27,640 --> 00:33:29,530 from NASA's Kepler mission. 719 00:33:29,530 --> 00:33:32,360 After four years staring into the Milky Way, 720 00:33:32,360 --> 00:33:35,450 Bill Borucki is ready to reveal his top picks 721 00:33:35,450 --> 00:33:38,113 from the hundreds of planets discovered so far. 722 00:33:39,210 --> 00:33:42,240 Today of like to announce, we have found two planets, 723 00:33:42,240 --> 00:33:44,650 that in a habitable zone of another star, 724 00:33:44,650 --> 00:33:47,370 and they are the best candidates found to date. 725 00:33:47,370 --> 00:33:50,520 They may have the possibility of water as well. 726 00:33:50,520 --> 00:33:53,310 (audience applauds) 727 00:33:53,310 --> 00:33:55,890 More than 1200 light years away, 728 00:33:55,890 --> 00:33:59,580 the most Earth-like of the two is called Kepler-62f 729 00:34:00,660 --> 00:34:04,260 and Borucki's data suggests it could be a water world 730 00:34:04,260 --> 00:34:06,623 completely covered by a vast ocean. 731 00:34:08,096 --> 00:34:10,440 (water gushing) 732 00:34:10,440 --> 00:34:13,080 The reason that we call it, perhaps a water world, 733 00:34:13,080 --> 00:34:17,200 is because given its mass and radius, it could in fact 734 00:34:17,200 --> 00:34:21,243 harbor a huge envelope of water on the surface. 735 00:34:21,243 --> 00:34:23,810 (gentle music) 736 00:34:23,810 --> 00:34:27,210 All sorts of life could exist in that ocean. 737 00:34:27,210 --> 00:34:29,010 Could you have all sorts of little creatures 738 00:34:29,010 --> 00:34:30,220 and fish to eat them, 739 00:34:30,220 --> 00:34:31,960 and fish that don't want to be eaten, 740 00:34:31,960 --> 00:34:33,900 so they learn to fly out of the ocean, 741 00:34:33,900 --> 00:34:35,925 like our flying fish do? 742 00:34:35,925 --> 00:34:37,370 (gentle music) 743 00:34:37,370 --> 00:34:40,313 Kepler-62f was certainly a high point. 744 00:34:41,250 --> 00:34:43,030 We were delighted to find that. 745 00:34:43,030 --> 00:34:45,600 And so were our sponsors at NASA headquarters 746 00:34:45,600 --> 00:34:46,955 who paid for this. 747 00:34:46,955 --> 00:34:49,460 (audience applauds) 748 00:34:49,460 --> 00:34:51,020 But behind the scenes, 749 00:34:51,020 --> 00:34:53,770 the Kepler mission faces a crisis. 750 00:34:53,770 --> 00:34:57,210 The telescope's ability to stare at the same patch of sky 751 00:34:57,210 --> 00:35:00,060 depends on four gyroscopic stabilizers 752 00:35:00,060 --> 00:35:01,913 called reaction wheels. 753 00:35:02,910 --> 00:35:05,429 That guidance system was so good, 754 00:35:05,429 --> 00:35:08,260 the image of the same star sent a same pixel, 755 00:35:08,260 --> 00:35:10,560 month after a month. 756 00:35:10,560 --> 00:35:15,030 But in 2013, two of the reaction wheels fail. 757 00:35:15,030 --> 00:35:17,010 That meant we could no longer point 758 00:35:17,010 --> 00:35:18,483 at that area of the sky. 759 00:35:19,400 --> 00:35:23,040 Telescope still worked, but we couldn't point there anymore. 760 00:35:25,720 --> 00:35:28,877 Really, really a tense, tense period. 761 00:35:28,877 --> 00:35:30,250 (upbeat music) 762 00:35:30,250 --> 00:35:31,870 I thought the mission was done for. 763 00:35:31,870 --> 00:35:33,950 I thought, well, got a good run, 764 00:35:33,950 --> 00:35:36,193 got a lot of good data, but it's done for. 765 00:35:37,070 --> 00:35:39,210 But Borucki is not done yet. 766 00:35:39,210 --> 00:35:41,257 Perhaps the mission can be salvaged. 767 00:35:41,257 --> 00:35:42,190 (upbeat music) 768 00:35:42,190 --> 00:35:45,900 The team sent out an all-points bulletin, 769 00:35:45,900 --> 00:35:49,313 you know, "Help, help, help" to the aerospace community. 770 00:35:51,060 --> 00:35:53,810 All objects in space feel a slight push 771 00:35:53,810 --> 00:35:55,590 from the light of the Sun, 772 00:35:55,590 --> 00:35:57,963 a phenomenon called solar pressure. 773 00:35:59,070 --> 00:36:03,320 Bill learns that this might be the solution to the problem. 774 00:36:03,320 --> 00:36:04,387 The engineers have pointed out, 775 00:36:04,387 --> 00:36:06,167 "You know, we've got two wheels 776 00:36:06,167 --> 00:36:09,533 "and we've got the Sun shining, pushing on the spacecraft. 777 00:36:10,937 --> 00:36:14,896 "We'll arrange it so the Sun acts like one of the wheels." 778 00:36:14,896 --> 00:36:16,490 (upbeat music) 779 00:36:16,490 --> 00:36:19,210 Each square meter of a satellite like Kepler 780 00:36:19,210 --> 00:36:21,700 feels solar pressure equivalent to the weight 781 00:36:21,700 --> 00:36:23,143 of a grain of salt on Earth. 782 00:36:24,200 --> 00:36:27,530 The engineers hope that this tiny force will be enough 783 00:36:27,530 --> 00:36:30,390 to stabilize the drifting telescope. 784 00:36:30,390 --> 00:36:32,030 (upbeat music) 785 00:36:32,030 --> 00:36:36,550 Clever idea, the way you use the very pressure 786 00:36:36,550 --> 00:36:39,150 of the radiation from the Sun 787 00:36:39,150 --> 00:36:43,300 as a countervailing force and thereby maintain stability 788 00:36:43,300 --> 00:36:45,240 and extend the life of the mission, 789 00:36:45,240 --> 00:36:46,653 to collect even more data. 790 00:36:47,970 --> 00:36:50,610 The ingenious fix is a success, 791 00:36:50,610 --> 00:36:52,330 but stabilizes the telescope 792 00:36:52,330 --> 00:36:55,040 for much shorter periods than before, 793 00:36:55,040 --> 00:36:56,943 with consequences for the mission. 794 00:36:58,010 --> 00:37:00,220 You could find short period of planets, 795 00:37:00,220 --> 00:37:02,330 giant plants with one or two orbits, 796 00:37:02,330 --> 00:37:06,690 but it didn't allow us to continue the original mission 797 00:37:06,690 --> 00:37:08,556 for finding Earths. 798 00:37:08,556 --> 00:37:11,139 (gentle music) 799 00:37:12,640 --> 00:37:13,740 We needed more time. 800 00:37:14,998 --> 00:37:16,620 And so we were not able to find 801 00:37:16,620 --> 00:37:20,213 that possibly true Earth analog. 802 00:37:21,300 --> 00:37:24,080 On October the 30th, 2018, 803 00:37:24,080 --> 00:37:27,330 the Kepler space telescope runs out of fuel. 804 00:37:27,330 --> 00:37:30,310 (gentle music) 805 00:37:30,310 --> 00:37:33,070 The mission accomplished its objective. 806 00:37:33,070 --> 00:37:37,228 So, okay, it died, it did its job. 807 00:37:37,228 --> 00:37:38,510 (gentle music) 808 00:37:38,510 --> 00:37:42,620 The Kepler discovers over 2,600 exoplanets 809 00:37:42,620 --> 00:37:45,290 with several hundred in the habitable zone. 810 00:37:45,290 --> 00:37:48,540 But the real surprise is the incredible diversity 811 00:37:48,540 --> 00:37:49,593 of these worlds. 812 00:37:51,120 --> 00:37:53,850 Kepler found so many new types of planets, 813 00:37:53,850 --> 00:37:56,660 just wow, opened up our eyes. 814 00:37:56,660 --> 00:37:59,330 The planetary systems weren't like ours at all. 815 00:37:59,330 --> 00:38:02,260 They had at big planets were we had little planets. 816 00:38:02,260 --> 00:38:04,850 Giant planets, bigger than Jupiter, 817 00:38:04,850 --> 00:38:07,636 little tiny planets disintegrating. 818 00:38:07,636 --> 00:38:09,340 (gentle music) 819 00:38:09,340 --> 00:38:13,400 Kepler really showed that there's an interstellar zoo 820 00:38:13,400 --> 00:38:15,565 of planetary worlds. 821 00:38:15,565 --> 00:38:16,920 (gentle music) 822 00:38:16,920 --> 00:38:20,110 The types of exoplanets that exist out there 823 00:38:20,110 --> 00:38:22,828 it's really, as far as your imagination can reach. 824 00:38:22,828 --> 00:38:24,850 (gentle upbeat music) 825 00:38:24,850 --> 00:38:26,880 At NASA's jet propulsion lab, 826 00:38:26,880 --> 00:38:29,770 observational data from surveys like Kepler 827 00:38:29,770 --> 00:38:31,980 is used to model the conditions 828 00:38:31,980 --> 00:38:35,403 on some of the extraordinary worlds in the cosmic zoo. 829 00:38:36,826 --> 00:38:39,270 It's really taking what data we have available to us, 830 00:38:39,270 --> 00:38:41,330 and then using our imagination 831 00:38:41,330 --> 00:38:43,300 to try and understand what their weather, 832 00:38:43,300 --> 00:38:44,880 what their atmospheres might be like. 833 00:38:44,880 --> 00:38:46,810 And really start to hammer down 834 00:38:46,810 --> 00:38:48,860 on whether or not there's life out there. 835 00:38:50,200 --> 00:38:51,230 The number crunching 836 00:38:51,230 --> 00:38:53,690 has led to some astonishing conclusions 837 00:38:53,690 --> 00:38:56,283 about the exoplanets in our backyard. 838 00:38:57,600 --> 00:39:00,500 55 Cancri e, what's not imagination 839 00:39:00,500 --> 00:39:04,620 is the fact that we can actually see the star by eye. 840 00:39:04,620 --> 00:39:05,610 (gentle music) 841 00:39:05,610 --> 00:39:09,350 40 light years away, 55 Cancri e 842 00:39:09,350 --> 00:39:11,859 is twice the size of Earth. 843 00:39:11,859 --> 00:39:14,490 (gentle music) 844 00:39:14,490 --> 00:39:17,503 It's in a ridiculously close orbit around its star. 845 00:39:18,970 --> 00:39:22,973 So surface temperatures might well be above 1,000 Calvin. 846 00:39:25,880 --> 00:39:29,500 So when I think of 55 Cancri e, I just think of lava. 847 00:39:29,500 --> 00:39:30,590 (laughing) 848 00:39:30,590 --> 00:39:34,492 None of the solids on the surface are able to stay solid. 849 00:39:34,492 --> 00:39:36,300 (gentle music) 850 00:39:36,300 --> 00:39:39,500 The lavas way too hard to remain liquid all the time. 851 00:39:39,500 --> 00:39:43,283 So there will be some kind of silicate gas as well. 852 00:39:44,210 --> 00:39:46,390 On the backside of the planet, 853 00:39:46,390 --> 00:39:51,000 it might well be that the gaseous rock steam atmosphere 854 00:39:51,000 --> 00:39:54,890 forms droplets, and actually rains out. 855 00:39:54,890 --> 00:39:55,960 And what does it rain out? 856 00:39:55,960 --> 00:39:57,483 Then of course rocks. 857 00:39:58,430 --> 00:40:01,842 So that's a very weird atmospheric scenario. 858 00:40:01,842 --> 00:40:04,425 (gentle music) 859 00:40:06,520 --> 00:40:09,070 Despite the apocalyptic conditions, 860 00:40:09,070 --> 00:40:12,233 this could be the most precious exoplanet yet discovered. 861 00:40:13,313 --> 00:40:16,680 If you look at the star that 55 Cancri e is orbiting, 862 00:40:16,680 --> 00:40:20,470 is actually a lot more carbon-rich than that at the Sun. 863 00:40:20,470 --> 00:40:24,119 So 55 Cancri e might be a carbon world. 864 00:40:24,119 --> 00:40:25,660 (gentle upbeat music) 865 00:40:25,660 --> 00:40:27,870 What happens in a planetary system 866 00:40:27,870 --> 00:40:30,530 where there's more carbon than oxygen, 867 00:40:30,530 --> 00:40:32,470 there could be a layer or part of the planet 868 00:40:32,470 --> 00:40:34,219 that has diamonds. 869 00:40:34,219 --> 00:40:35,950 (gentle upbeat music) 870 00:40:35,950 --> 00:40:38,257 These are real places we can point to and say, 871 00:40:38,257 --> 00:40:41,367 "Yeah, this indeed is a planet that'll rain, 872 00:40:41,367 --> 00:40:44,766 "you know, diamonds, or has a surface of liquid lava." 873 00:40:44,766 --> 00:40:45,850 (gentle upbeat music) 874 00:40:45,850 --> 00:40:48,250 These are the worlds that exist in our universe. 875 00:40:50,300 --> 00:40:53,830 55 Cancri e is a nightmare world 876 00:40:53,830 --> 00:40:56,360 where life must be impossible. 877 00:40:56,360 --> 00:40:59,270 But in 2017 and equally bizarre, 878 00:40:59,270 --> 00:41:02,820 but utterly different planetary system is discovered 879 00:41:02,820 --> 00:41:05,560 at about the same distance from Earth. 880 00:41:05,560 --> 00:41:06,710 TRAPPIST-1 is a system 881 00:41:06,710 --> 00:41:11,433 comprised of seven closely-packed planets 882 00:41:11,433 --> 00:41:14,130 that are all roughly Earth-sized, 883 00:41:14,130 --> 00:41:17,222 orbiting what's called an M dwarf star. 884 00:41:17,222 --> 00:41:18,710 (gentle music) 885 00:41:18,710 --> 00:41:20,370 The TRAPPIST-1 system is exciting 886 00:41:20,370 --> 00:41:22,920 because it looks like our solar system. 887 00:41:22,920 --> 00:41:25,200 It's got a whole bunch of planets 888 00:41:25,200 --> 00:41:29,801 and maybe two or three of them are in a habitable zone. 889 00:41:29,801 --> 00:41:31,610 (gentle upbeat music) 890 00:41:31,610 --> 00:41:33,030 And that's really exciting. 891 00:41:33,030 --> 00:41:34,570 It's just, you know, this is the model 892 00:41:34,570 --> 00:41:36,550 that we all had in our minds 893 00:41:36,550 --> 00:41:38,650 of what could happen around all the stars. 894 00:41:40,290 --> 00:41:44,830 The star itself is a much cooler, redder 895 00:41:44,830 --> 00:41:47,290 and smaller star than the Sun. 896 00:41:47,290 --> 00:41:49,870 And indeed the solar system around TRAPPIST 897 00:41:49,870 --> 00:41:52,000 is tucked in closer to this star. 898 00:41:52,000 --> 00:41:54,850 You get the same kind of temperatures you get from Earth. 899 00:41:56,630 --> 00:41:58,480 This mini solar system 900 00:41:58,480 --> 00:42:01,010 could even have liquid water oceans. 901 00:42:01,010 --> 00:42:02,340 (gentle upbeat music) 902 00:42:02,340 --> 00:42:04,540 The orbital configuration indicates 903 00:42:04,540 --> 00:42:06,610 the planets may have migrated 904 00:42:06,610 --> 00:42:08,758 from further from their star, originally. 905 00:42:08,758 --> 00:42:10,440 (upbeat music) 906 00:42:10,440 --> 00:42:11,850 And so they've had the opportunity 907 00:42:11,850 --> 00:42:13,893 to accumulate a lot of ice, 908 00:42:14,860 --> 00:42:17,133 which then melted to form water. 909 00:42:21,100 --> 00:42:22,830 So if it were possible to stand 910 00:42:22,830 --> 00:42:25,100 or float on a TRAPPIST-1 planet, 911 00:42:25,100 --> 00:42:28,260 then you would see the star is much closer, 912 00:42:28,260 --> 00:42:31,349 but it's also dimer and redder than our own Sun. 913 00:42:31,349 --> 00:42:33,192 (upbeat music) 914 00:42:33,192 --> 00:42:35,380 You wouldn't just have a moon in the sky, 915 00:42:35,380 --> 00:42:37,980 but instead you'd be seeing the neighboring planets. 916 00:42:39,070 --> 00:42:41,030 Everything that we would see was our human eye 917 00:42:41,030 --> 00:42:41,973 would be red. 918 00:42:43,030 --> 00:42:44,190 Plants with green leaves, 919 00:42:44,190 --> 00:42:46,080 they would appear black to our eye. 920 00:42:46,080 --> 00:42:48,498 I mean, everything is exotic. 921 00:42:48,498 --> 00:42:49,360 (upbeat music) 922 00:42:49,360 --> 00:42:52,860 M Dwarf stars, like TRAPPIST-1 are so dim 923 00:42:52,860 --> 00:42:55,920 that from Earth they're to the naked eye, 924 00:42:55,920 --> 00:42:59,330 but they're the most common type of star in the galaxy, 925 00:42:59,330 --> 00:43:02,193 outnumbering Sun-like stars 10 to one. 926 00:43:03,350 --> 00:43:05,280 This is the majority of stars out there. 927 00:43:05,280 --> 00:43:06,810 And the majority of stars 928 00:43:06,810 --> 00:43:08,760 might have these little mini solar systems 929 00:43:08,760 --> 00:43:10,573 with habitable, like planets. 930 00:43:11,970 --> 00:43:13,210 TRAPPIST-1 offers 931 00:43:13,210 --> 00:43:15,223 a recognizable template for life. 932 00:43:16,060 --> 00:43:18,730 But could recent observations of our nearest star, 933 00:43:18,730 --> 00:43:23,000 Proxima Centauri, suggest we already have neighbors. 934 00:43:23,000 --> 00:43:25,583 (upbeat music) 935 00:43:27,940 --> 00:43:29,720 Proxima Centauri b, I think, 936 00:43:29,720 --> 00:43:31,950 has captured a lot of people's imagination 937 00:43:31,950 --> 00:43:35,760 because it's one of the closest systems we can investigate. 938 00:43:35,760 --> 00:43:37,883 It's only four light years away. 939 00:43:39,450 --> 00:43:40,700 It's in the habitable zone. 940 00:43:40,700 --> 00:43:41,860 So as heated by the star, 941 00:43:41,860 --> 00:43:44,203 it should be the right temperature for life. 942 00:43:45,150 --> 00:43:48,263 Sounds positive, but then things get weird. 943 00:43:50,610 --> 00:43:55,610 We think that it is tightly locked to its star, 944 00:43:55,720 --> 00:43:59,010 like the moon is locked to the Earth. 945 00:43:59,010 --> 00:44:03,503 That means one hemisphere is facing the star permanently. 946 00:44:05,190 --> 00:44:06,170 So could a world 947 00:44:06,170 --> 00:44:09,610 split between permanent day and eternal night, 948 00:44:09,610 --> 00:44:11,364 ever support life? 949 00:44:11,364 --> 00:44:13,520 (gentle upbeat music) 950 00:44:13,520 --> 00:44:16,500 We think any water on Proxima Centauri b 951 00:44:16,500 --> 00:44:19,613 would probably end up on the night side and frozen. 952 00:44:21,460 --> 00:44:23,760 But ice that's forming on the night side 953 00:44:23,760 --> 00:44:25,950 could start to creep towards the day side, 954 00:44:25,950 --> 00:44:28,003 and it would start to melt. 955 00:44:28,848 --> 00:44:32,015 (gentle upbeat music) 956 00:44:33,050 --> 00:44:36,260 There is a region, a rim or a ring 957 00:44:36,260 --> 00:44:39,590 around the planet that we refer to as The Terminator, 958 00:44:39,590 --> 00:44:41,680 The Terminator zone, the transition zone 959 00:44:41,680 --> 00:44:44,220 between bright and dark, 960 00:44:44,220 --> 00:44:47,040 where the conditions might be just very favorable 961 00:44:47,040 --> 00:44:49,195 for life to have formed. 962 00:44:49,195 --> 00:44:51,130 (gentle upbeat music) 963 00:44:51,130 --> 00:44:52,940 These organisms would have to deal 964 00:44:52,940 --> 00:44:56,130 with the perils of being so close to their star. 965 00:44:56,130 --> 00:44:58,563 A particularly volatile red dwarf. 966 00:45:00,080 --> 00:45:03,060 Though the smallest and dimmest kind of star, 967 00:45:03,060 --> 00:45:05,600 at less than 5 billion years old, 968 00:45:05,600 --> 00:45:10,020 Proxima Centauri is very young for a red dwarf 969 00:45:10,020 --> 00:45:12,593 and is prone to violent outbursts. 970 00:45:13,830 --> 00:45:17,320 When a red dwarf is young, it emits a lot more radiation, 971 00:45:17,320 --> 00:45:18,932 including stellar flares. 972 00:45:18,932 --> 00:45:20,150 (upbeat music) 973 00:45:20,150 --> 00:45:23,753 So the planet's also going to be blasted with radiation. 974 00:45:24,620 --> 00:45:28,900 Proxima Centauri b may be getting flared every week, 975 00:45:28,900 --> 00:45:32,000 but the flare probably wouldn't kill life. 976 00:45:32,000 --> 00:45:33,920 You know, there's always the dark side of the planet. 977 00:45:33,920 --> 00:45:36,190 There's always the oceans, if there are oceans. 978 00:45:36,190 --> 00:45:38,470 So I'm not too worried about life itself, 979 00:45:38,470 --> 00:45:39,700 not being able to survive. 980 00:45:39,700 --> 00:45:42,533 It just will create a very tricky landscape. 981 00:45:44,760 --> 00:45:46,480 The violent stellar activity 982 00:45:46,480 --> 00:45:49,540 could also create a spectacular light show 983 00:45:49,540 --> 00:45:52,374 for those brave enough to venture out. 984 00:45:52,374 --> 00:45:53,980 (gentle upbeat music) 985 00:45:53,980 --> 00:45:55,540 It could be that there's periodically 986 00:45:55,540 --> 00:45:57,300 a transfer of high energy particles 987 00:45:57,300 --> 00:45:58,700 from the star to the planet, 988 00:45:59,680 --> 00:46:01,980 creating an Aurora that might be ever present. 989 00:46:03,120 --> 00:46:05,730 So could Proxima Centauri b, 990 00:46:05,730 --> 00:46:07,333 be a home from home? 991 00:46:09,690 --> 00:46:12,532 Well, Proxima Centauri b is the closest world, 992 00:46:12,532 --> 00:46:15,004 other than our solar system. 993 00:46:15,004 --> 00:46:16,390 (gentle upbeat music) 994 00:46:16,390 --> 00:46:20,980 So one of the first places that humankind will explore, 995 00:46:20,980 --> 00:46:25,076 if we go interstellar will be Proxima Centauri b. 996 00:46:25,076 --> 00:46:26,630 (gentle upbeat music) 997 00:46:26,630 --> 00:46:30,130 In Proxima Centauri b we could discover 998 00:46:30,130 --> 00:46:33,550 that Earth really does have a twin, 999 00:46:33,550 --> 00:46:35,303 just not an identical twin. 1000 00:46:36,419 --> 00:46:38,760 (gentle music) 1001 00:46:38,760 --> 00:46:42,350 Progress in exoplanet research is staggering, 1002 00:46:42,350 --> 00:46:44,670 but everything we know has been discovered 1003 00:46:44,670 --> 00:46:46,063 in a single generation. 1004 00:46:47,630 --> 00:46:50,320 We take for granted that there are exoplanets 1005 00:46:50,320 --> 00:46:52,360 orbiting around other stars. 1006 00:46:52,360 --> 00:46:56,638 And yet only a few decades ago, we had not seen one. 1007 00:46:56,638 --> 00:46:59,120 (gentle music) 1008 00:46:59,120 --> 00:47:01,370 {\an8}Less than 40 years after Richard Terrile 1009 00:47:01,370 --> 00:47:05,520 {\an8}photographed the fuzzy debris disc around Beta Pictoris, 1010 00:47:05,520 --> 00:47:07,940 this astonishing footage of an exoplanet 1011 00:47:07,940 --> 00:47:11,225 actually orbiting the star was released. 1012 00:47:11,225 --> 00:47:14,330 (gentle music) 1013 00:47:14,330 --> 00:47:17,350 We've come from these crude images in a coronagraph 1014 00:47:17,350 --> 00:47:20,943 to actually seeing an exoplanet orbiting that star. 1015 00:47:21,961 --> 00:47:23,860 It's very, very exciting to see that progression, 1016 00:47:23,860 --> 00:47:26,347 see that evolution of our knowledge. 1017 00:47:26,347 --> 00:47:27,230 (gentle music) 1018 00:47:27,230 --> 00:47:30,490 Beta Pictoris b, it's actually called a super Jupiter 1019 00:47:30,490 --> 00:47:33,300 because it's more massive than Jupiter. 1020 00:47:33,300 --> 00:47:34,660 We've also been able to measure 1021 00:47:34,660 --> 00:47:36,663 the rotation rate of the planet. 1022 00:47:37,630 --> 00:47:39,380 This might actually resemble Jupiter, 1023 00:47:39,380 --> 00:47:41,800 in that it should have a lot of bands and vortices 1024 00:47:41,800 --> 00:47:43,963 that rotate in the atmosphere. 1025 00:47:43,963 --> 00:47:46,730 (gentle music) 1026 00:47:46,730 --> 00:47:47,790 We were the first to see it. 1027 00:47:47,790 --> 00:47:51,239 And now it's to this interstellar zoo. 1028 00:47:51,239 --> 00:47:53,200 (gentle music) 1029 00:47:53,200 --> 00:47:55,480 It's a great thing to have on your resume. 1030 00:47:55,480 --> 00:47:57,020 (gentle music) 1031 00:47:57,020 --> 00:47:58,800 Every advance in technology 1032 00:47:58,800 --> 00:48:02,490 has added new detail to the exoplanet story, 1033 00:48:02,490 --> 00:48:06,186 but are we any closer to answering the big question? 1034 00:48:06,186 --> 00:48:08,200 (gentle music) 1035 00:48:08,200 --> 00:48:11,323 Are we at the cusp of finding life today? 1036 00:48:14,490 --> 00:48:16,270 I would say no, 1037 00:48:16,270 --> 00:48:18,010 but we have a roadmap. 1038 00:48:18,010 --> 00:48:20,430 We know what we are looking for. 1039 00:48:20,430 --> 00:48:23,110 And we are developing the technology 1040 00:48:23,110 --> 00:48:25,110 to look for those traces 1041 00:48:25,110 --> 00:48:28,025 that we think could be evidence of life. 1042 00:48:28,025 --> 00:48:28,890 (gentle music) 1043 00:48:28,890 --> 00:48:31,120 We look at the missions that are being planned, 1044 00:48:31,120 --> 00:48:33,070 that are such huge telescopes, 1045 00:48:33,070 --> 00:48:35,373 that we can see the atmospheres of planets. 1046 00:48:36,390 --> 00:48:37,980 What's in that atmosphere? 1047 00:48:37,980 --> 00:48:39,483 Is there some signs of life? 1048 00:48:40,430 --> 00:48:42,003 Maybe even see the planets? 1049 00:48:42,890 --> 00:48:46,090 Well, we see the ingredients for life everywhere, 1050 00:48:46,090 --> 00:48:48,460 but most of the universe is, I would say, 1051 00:48:48,460 --> 00:48:49,823 hostile towards life. 1052 00:48:51,060 --> 00:48:53,160 But I don't know, I don't feel the need to speculate. 1053 00:48:53,160 --> 00:48:54,640 The great thing about astronomy 1054 00:48:54,640 --> 00:48:58,293 is it won't be long before we have better answers. 1055 00:48:59,460 --> 00:49:01,850 And that all of our speculations and dreams, 1056 00:49:01,850 --> 00:49:04,637 we can see which one of those are real. 1057 00:49:04,637 --> 00:49:07,038 (gentle music) 1058 00:49:07,038 --> 00:49:10,413 The universe is far more exciting than it was 40 years ago 1059 00:49:10,413 --> 00:49:13,350 when our imaginations didn't comprehend 1060 00:49:13,350 --> 00:49:15,350 the different environments that we have. 1061 00:49:16,230 --> 00:49:19,230 But I think the future is also gonna be very, very exciting. 1062 00:49:20,090 --> 00:49:22,970 You know, this first step was finding planets, 1063 00:49:22,970 --> 00:49:25,274 the next step is finding life. 1064 00:49:25,274 --> 00:49:27,857 (gentle music)