1 00:00:01,280 --> 00:00:03,200 Ever seen a UFO? 2 00:00:03,200 --> 00:00:05,600 However implausible they may be, 3 00:00:05,600 --> 00:00:09,080 the idea holds a powerful grip on our collective imagination. 4 00:00:10,320 --> 00:00:13,160 And UFOs raise fascinating questions, 5 00:00:13,160 --> 00:00:16,320 not just about what particular sightings might be but also 6 00:00:16,320 --> 00:00:20,760 about the nature of space travel and communication across the universe. 7 00:00:24,800 --> 00:00:28,680 Answering those questions involves some incredible science. 8 00:00:28,680 --> 00:00:33,080 And so this month, we ask, "What have UFOs ever done for us?" 9 00:01:00,960 --> 00:01:04,240 Since I was a little girl, I always hoped that one day 10 00:01:04,240 --> 00:01:07,480 I would wake up to find visitors from another world. 11 00:01:07,480 --> 00:01:09,200 Sadly, I'm still waiting. 12 00:01:09,200 --> 00:01:11,680 I wish we could bring you the first interview with aliens 13 00:01:11,680 --> 00:01:14,480 but instead, we are back here at the Jodrell Bank Observatory, 14 00:01:14,480 --> 00:01:17,640 a place long associated with the search for extraterrestrial 15 00:01:17,640 --> 00:01:21,200 intelligence and somewhere which is famous for studying objects 16 00:01:21,200 --> 00:01:24,880 so strange that they were labelled as little green men. 17 00:01:24,880 --> 00:01:27,640 But this month is also a poignant reminder of how difficult 18 00:01:27,640 --> 00:01:29,320 space travel is. 19 00:01:29,320 --> 00:01:31,320 11 years after it disappeared, 20 00:01:31,320 --> 00:01:35,280 the Beagle 2 spacecraft has been found on the surface of Mars. 21 00:01:35,280 --> 00:01:38,960 We celebrate a mission that came tantalisingly close to triumph. 22 00:01:40,880 --> 00:01:44,480 Coming up, Dallas Campbell opens the MOD's UFO files 23 00:01:44,480 --> 00:01:47,840 and asks what it would take for aliens to visit us. 24 00:01:47,840 --> 00:01:50,640 There are some basic questions we have to ask 25 00:01:50,640 --> 00:01:54,760 and one of those questions is, "Is interstellar travel possible?" 26 00:01:54,760 --> 00:01:56,880 Pete reveals what really lies behind 27 00:01:56,880 --> 00:01:59,000 some of the most common UFO sightings. 28 00:02:01,040 --> 00:02:05,080 Plus, the unexpected radio signal that for a brief moment 29 00:02:05,080 --> 00:02:09,480 looked like it might just be communications from little green men. 30 00:02:09,480 --> 00:02:13,240 It was pulsing, which is not what a radio astronomer 31 00:02:13,240 --> 00:02:15,480 expects from the sky. 32 00:02:19,040 --> 00:02:21,880 The three little letters, U-F-O, 33 00:02:21,880 --> 00:02:24,200 conjures up all sorts of images in our minds 34 00:02:24,200 --> 00:02:26,720 and have led to countless controversies. 35 00:02:26,720 --> 00:02:28,600 Of course, when we talk about UFOs, 36 00:02:28,600 --> 00:02:31,760 we are talking about the idea of visitors from outer space. 37 00:02:31,760 --> 00:02:34,960 Although science doesn't preclude the existence of life 38 00:02:34,960 --> 00:02:36,760 elsewhere in the universe, 39 00:02:36,760 --> 00:02:40,880 scientists are extremely dubious about UFOs visiting us here on Earth. 40 00:02:40,880 --> 00:02:44,720 Despite this, sightings keep coming in thick and fast. 41 00:02:44,720 --> 00:02:47,280 We have asked Dallas Campbell to investigate 42 00:02:47,280 --> 00:02:50,800 what people are seeing and to find out why the probability of aliens 43 00:02:50,800 --> 00:02:53,240 visiting our planet is so unlikely. 44 00:02:58,080 --> 00:03:02,240 The modern UFO phenomenon began in 1947. 45 00:03:02,240 --> 00:03:04,760 An American pilot, Kenneth Arnold, 46 00:03:04,760 --> 00:03:08,480 was flying above the Cascade Mountains in Washington state 47 00:03:08,480 --> 00:03:13,160 where he describes seeing nine saucerlike objects 48 00:03:13,160 --> 00:03:17,880 flying as if they were being skimmed across the water. 49 00:03:17,880 --> 00:03:22,080 Since then, thousands of UFO sightings have been reported - 50 00:03:22,080 --> 00:03:26,800 bright lights, mysterious dark shapes and even the odd abduction. 51 00:03:26,800 --> 00:03:29,440 At the National Archives in south London, 52 00:03:29,440 --> 00:03:33,400 a wealth of these documented sightings are safely stored away. 53 00:03:33,400 --> 00:03:34,880 These are really exciting. 54 00:03:34,880 --> 00:03:38,800 These are the official X files documents, if you like. 55 00:03:38,800 --> 00:03:43,600 These are the MoD collated reports of unidentified flying objects. 56 00:03:43,600 --> 00:03:47,480 There was a great story of a whole load of schoolchildren 57 00:03:47,480 --> 00:03:50,040 who had seen an unidentified flying object and had 58 00:03:50,040 --> 00:03:54,200 written into the Ministry of Defence and all the letters are still here. 59 00:03:54,200 --> 00:03:57,120 Some of the children had actually drawn pictures of what 60 00:03:57,120 --> 00:03:58,680 they had seen. 61 00:03:58,680 --> 00:04:04,040 There is letter here from the MoD dated 1967 telling the children 62 00:04:04,040 --> 00:04:08,200 there were, in fact, low-flying aircraft in the area at the time. 63 00:04:08,200 --> 00:04:11,000 Sounds pretty plausible to me. 64 00:04:11,000 --> 00:04:15,920 This flying saucer report actually made the papers. This is from 1966. 65 00:04:15,920 --> 00:04:19,360 This amazing picture of a flying saucer filmed from an aircraft 66 00:04:19,360 --> 00:04:23,000 by a woman "will set the world talking" and it certainly did. 67 00:04:23,000 --> 00:04:27,840 But, luckily, good old Tomorrow's World solved the mystery. 68 00:04:27,840 --> 00:04:30,560 'Our cameraman sat in the same seat as Mrs Oldfield had. 69 00:04:30,560 --> 00:04:31,920 'Through the window, 70 00:04:31,920 --> 00:04:35,840 'notice how the glass is slightly convex where it meets the frame. 71 00:04:35,840 --> 00:04:39,400 'Here it comes. Tomorrow's World very own UFO. 72 00:04:41,200 --> 00:04:44,200 'What we are seeing now is a direct view of the tailplane 73 00:04:44,200 --> 00:04:48,000 'of the aircraft seen at an acute angle to the window glass.' 74 00:04:49,800 --> 00:04:52,800 Whether these UFO reports are unexplainable or not, 75 00:04:52,800 --> 00:04:55,960 it's worth thinking about the UFO question from a different angle. 76 00:04:55,960 --> 00:04:59,840 If a civilisation was visiting the Earth from a faraway 77 00:04:59,840 --> 00:05:03,680 solar system, there are some basic questions we have to ask 78 00:05:03,680 --> 00:05:07,000 and one of those questions is, "Is interstellar travel possible?" 79 00:05:09,320 --> 00:05:12,840 We live in a world governed by the laws of physics. 80 00:05:12,840 --> 00:05:16,960 And to the best of our knowledge, they apply throughout the universe. 81 00:05:16,960 --> 00:05:19,880 It's these laws that make interstellar travel 82 00:05:19,880 --> 00:05:22,640 so incredibly improbable. 83 00:05:22,640 --> 00:05:25,800 Of course, the problem with travelling around space is 84 00:05:25,800 --> 00:05:28,640 that space is big, really big, 85 00:05:28,640 --> 00:05:32,080 and the distance between stars is absolutely vast. 86 00:05:32,080 --> 00:05:37,000 It's so vast that even light, which is the fastest thing we know, 87 00:05:37,000 --> 00:05:39,080 takes years to travel between them. 88 00:05:41,120 --> 00:05:44,840 Even our fastest spacecraft like Voyager 1 89 00:05:44,840 --> 00:05:49,400 would take at least 70,000 years just to reach our nearest star. 90 00:05:51,400 --> 00:05:55,680 So, how could we or any other spacefarers cross such 91 00:05:55,680 --> 00:06:01,240 unimaginable distances? Well, you could try going really, really fast. 92 00:06:03,400 --> 00:06:06,760 But going faster is incredibly difficult and not 93 00:06:06,760 --> 00:06:11,080 just for the obvious reason that it takes a great deal of effort. 94 00:06:11,080 --> 00:06:15,680 Over a century ago, Einstein worked out that the faster you travel, 95 00:06:15,680 --> 00:06:17,920 the heavier you get. 96 00:06:17,920 --> 00:06:20,360 If I were to accelerate up to the speed of light, 97 00:06:20,360 --> 00:06:23,240 my mass would become infinite 98 00:06:23,240 --> 00:06:26,560 and the amount of energy I would need to move would also be infinite, 99 00:06:26,560 --> 00:06:28,160 which might get a bit tiring. 100 00:06:29,800 --> 00:06:34,040 But, funnily enough, going fast is only part of the problem. 101 00:06:34,040 --> 00:06:37,080 Once you get to where you're going, how do you then stop? 102 00:06:38,400 --> 00:06:40,480 The faster you've been travelling, 103 00:06:40,480 --> 00:06:44,040 the harder it is to lose all that momentum you've built up. 104 00:06:44,040 --> 00:06:48,200 So, in order to stop in space, you would need another engine 105 00:06:48,200 --> 00:06:51,160 with the same force pushing you back the other way. 106 00:06:53,040 --> 00:06:56,520 And this is a problem we struggle with in our own solar system 107 00:06:56,520 --> 00:06:59,200 when we send probes to other planets. 108 00:06:59,200 --> 00:07:02,920 Stopping a spacecraft, once it has reached its destination, 109 00:07:02,920 --> 00:07:05,800 is one of the hardest things in space exploration. 110 00:07:08,000 --> 00:07:10,640 There may be a way round this, though. 111 00:07:10,640 --> 00:07:12,840 Instead of trying to go faster, 112 00:07:12,840 --> 00:07:15,960 could we not make the distance itself shorter? 113 00:07:18,920 --> 00:07:22,800 Crazy as that sounds, there may be a way to do just that. 114 00:07:24,120 --> 00:07:27,640 There's a theoretical solution to this interstellar dilemma - 115 00:07:27,640 --> 00:07:30,120 something known as a wormhole. 116 00:07:30,120 --> 00:07:32,440 These are tunnels through space time, 117 00:07:32,440 --> 00:07:34,880 connecting two distant places. 118 00:07:34,880 --> 00:07:36,840 Cosmic shortcuts like this 119 00:07:36,840 --> 00:07:40,040 could hold the key to visiting other worlds. 120 00:07:40,040 --> 00:07:44,040 I'm meeting theoretical astrophysicist Roberto Trotta 121 00:07:44,040 --> 00:07:48,120 to find out how likely these sci-fi staples really are. 122 00:07:48,120 --> 00:07:51,360 Theoretically, is it something we can even consider, 123 00:07:51,360 --> 00:07:53,480 even think about, even talk about? 124 00:07:53,480 --> 00:07:54,920 Conceivable, yes, absolutely 125 00:07:54,920 --> 00:07:57,480 and theoretically, you can find solutions 126 00:07:57,480 --> 00:08:00,840 to Einstein's general relativity equation that describe 127 00:08:00,840 --> 00:08:04,000 such a shortcut, a wormhole, in fact. 128 00:08:04,000 --> 00:08:07,320 But you want to be able to go through it and possibly come back. 129 00:08:07,320 --> 00:08:12,200 In theory, a wormhole could be formed by two black holes connecting 130 00:08:12,200 --> 00:08:15,480 to create a bridge but there's a problem. 131 00:08:15,480 --> 00:08:20,240 This possibility wouldn't be traversable. You couldn't take a shortcut through a black hole 132 00:08:20,240 --> 00:08:23,160 because, first of all, practically, you would be dead. 133 00:08:23,160 --> 00:08:26,120 It would hurt. It would hurt. Spaghettification terribly hurts. 134 00:08:26,120 --> 00:08:28,240 What do you call it? Spaghettification. 135 00:08:28,240 --> 00:08:32,680 When you get spaghettified by the tidal forces of gravity. 136 00:08:32,680 --> 00:08:34,720 That is something you don't want to do. 137 00:08:34,720 --> 00:08:36,640 So, in terms of... 138 00:08:36,640 --> 00:08:40,080 If you want to engineer the wormhole of a kind 139 00:08:40,080 --> 00:08:41,840 that would allow you safe travel, 140 00:08:41,840 --> 00:08:44,880 you might possibly be able to use one that is already there 141 00:08:44,880 --> 00:08:47,080 but even that is not guaranteed 142 00:08:47,080 --> 00:08:49,520 because the wormhole would need to have 143 00:08:49,520 --> 00:08:51,760 a large amount of negative energy, 144 00:08:51,760 --> 00:08:54,640 which is something we don't really know if it exists. 145 00:08:54,640 --> 00:08:57,640 But let me get this, we don't know if there are any wormholes, 146 00:08:57,640 --> 00:09:00,720 we haven't made one, this is all... All speculative. 147 00:09:00,720 --> 00:09:03,200 It's all equations on a board, effectively, 148 00:09:03,200 --> 00:09:05,560 people speculating about what kind of reality 149 00:09:05,560 --> 00:09:08,440 those equations could possibly describe. Got it. 150 00:09:08,440 --> 00:09:11,440 No-one said, "Ooh, look, what's that funny thing?" "A wormhole." 151 00:09:11,440 --> 00:09:14,240 No. We're not even... No, we don't even know how to look for one. 152 00:09:14,240 --> 00:09:17,240 So, let's assume a wormhole had happened. 153 00:09:17,240 --> 00:09:20,600 Presumably, we're going to run into all kinds of practical problems, still. 154 00:09:20,600 --> 00:09:23,400 It's not just, "We built a wormhole, we can all go on holiday." 155 00:09:23,400 --> 00:09:26,160 There is the strength of the forces, the time it would take, 156 00:09:26,160 --> 00:09:28,280 not to you as a traveller, 157 00:09:28,280 --> 00:09:31,240 but the time that would pass for people back home. 158 00:09:31,240 --> 00:09:34,760 Time would flow differently for you than for people back home 159 00:09:34,760 --> 00:09:37,520 and so you don't want to go on holiday and come back 160 00:09:37,520 --> 00:09:40,440 and everybody has died 10,000 years ago. That would be silly. 161 00:09:40,440 --> 00:09:42,920 And the other problem is that even just theoretically, 162 00:09:42,920 --> 00:09:45,400 um, if such wormholes were to exist, 163 00:09:45,400 --> 00:09:47,920 you could use them to travel back in time, 164 00:09:47,920 --> 00:09:51,440 which seems to be something that is fundamentally forbidden 165 00:09:51,440 --> 00:09:54,760 and that might be an argument why they might not exist. 166 00:09:54,760 --> 00:09:58,000 South of France is nice this time of year. 167 00:09:58,000 --> 00:10:00,200 I think I might just plump for that instead. Yes. 168 00:10:05,240 --> 00:10:08,760 Even though the probability of finding aliens that have 169 00:10:08,760 --> 00:10:11,560 zipped across the universe to visit us is very small, 170 00:10:11,560 --> 00:10:14,800 there is still a possibility that they are out there. 171 00:10:14,800 --> 00:10:16,880 As a result, we have combed the cosmos, 172 00:10:16,880 --> 00:10:19,240 searching for signs of their existence. 173 00:10:19,240 --> 00:10:22,800 Chris is speaking to pioneering astrophysicist Jocelyn Bell Burnell 174 00:10:22,800 --> 00:10:26,600 who discovered a signal that looked like the one we'd been waiting for. 175 00:10:29,080 --> 00:10:32,920 It had long been assumed that if an alien civilisation tried to make 176 00:10:32,920 --> 00:10:37,160 contact with us, the signal they send would have some key characteristics. 177 00:10:38,200 --> 00:10:41,920 It would be in the radio part of the spectrum, as radio waves travel 178 00:10:41,920 --> 00:10:45,400 easily across the vastness of interstellar space. 179 00:10:45,400 --> 00:10:47,840 It would be persistent, not a one-off, 180 00:10:47,840 --> 00:10:50,360 and it would have a rapidly repeating pattern. 181 00:10:51,640 --> 00:10:55,680 This is exactly what was found in 1967. 182 00:10:55,680 --> 00:10:58,840 Jocelyn, we have to start by talking about this remarkable discovery 183 00:10:58,840 --> 00:11:02,560 that you made in Cambridge in the late 1960s. 184 00:11:02,560 --> 00:11:06,840 So, what were radio telescopes like then? What were you using? 185 00:11:06,840 --> 00:11:08,760 Radio astronomy, 186 00:11:08,760 --> 00:11:10,600 at that stage, we quite often 187 00:11:10,600 --> 00:11:12,680 built our own radio telescopes - 188 00:11:12,680 --> 00:11:16,640 four and a half acres, lots and lots of wooden posts, 189 00:11:16,640 --> 00:11:21,160 looks a bit like a hop field, wires trailing along the top of the posts, 190 00:11:21,160 --> 00:11:24,760 120 miles of wire and cable in that radio telescope. 191 00:11:24,760 --> 00:11:26,760 But it worked. 192 00:11:26,760 --> 00:11:29,400 And the output was primitive, too? 193 00:11:29,400 --> 00:11:34,920 Yes, everything came out as hard copy. Moving pen over chart paper. 194 00:11:34,920 --> 00:11:37,240 Wiggle, wiggle, wiggle, wiggle - 195 00:11:37,240 --> 00:11:40,200 um, 100 feet of chart paper every day. 196 00:11:40,200 --> 00:11:45,440 And in inspecting that vast amount of paper, you spotted something unusual. 197 00:11:45,440 --> 00:11:49,280 What flagged this particular signal as an interesting discovery? 198 00:11:50,520 --> 00:11:54,400 Well, it didn't look exactly like the quasars which I was meant to be looking at. 199 00:11:54,400 --> 00:11:57,560 It didn't look exactly like interference. 200 00:11:57,560 --> 00:12:01,080 It turned out to be a thing that was pulsing 201 00:12:01,080 --> 00:12:04,560 once every one-and-a-third seconds, 202 00:12:04,560 --> 00:12:10,040 which is not what a radio astronomer expects from the sky. 203 00:12:10,040 --> 00:12:13,040 It's regular, and it's rapid. 204 00:12:13,040 --> 00:12:17,080 Stars can't turn on a sixpence, this thing was. 205 00:12:17,080 --> 00:12:19,600 What on earth is it? 206 00:12:19,600 --> 00:12:24,040 It has all the hallmarks of artificial, man-made interference, 207 00:12:24,040 --> 00:12:27,320 but it's coming from the same spot amongst the stars. 208 00:12:27,320 --> 00:12:31,280 So, it got this nickname, LGM-1 for "little green men." 209 00:12:31,280 --> 00:12:34,400 Was that a serious consideration, at the time? 210 00:12:34,400 --> 00:12:37,040 I named it, and I have to say I now regret it. 211 00:12:37,040 --> 00:12:39,840 It wasn't serious, it was very much tongue-in-cheek. 212 00:12:39,840 --> 00:12:45,040 And we did check out whether it might be little green men, 213 00:12:45,040 --> 00:12:47,600 extraterrestrial civilisations, 214 00:12:47,600 --> 00:12:52,640 arguing that if it is, those little green men live on a planet 215 00:12:52,640 --> 00:12:55,720 that goes round their sun. 216 00:12:55,720 --> 00:12:58,440 And as the planet goes around their sun, some of the time, it's 217 00:12:58,440 --> 00:13:02,120 coming towards you, the observer, and the pulses pile up closer. 218 00:13:02,120 --> 00:13:06,680 And sometimes it is moving away from you and the pulses spread out. 219 00:13:06,680 --> 00:13:10,920 So I did a lot of careful monitoring of pulse arrival times 220 00:13:10,920 --> 00:13:15,160 and we found one of these Doppler shifts, as it's called, 221 00:13:15,160 --> 00:13:18,280 but it was due to the motion of the Earth around the sun 222 00:13:18,280 --> 00:13:21,000 because Doppler shift works 223 00:13:21,000 --> 00:13:24,640 for the Earth moving, as well as the source of the radio waves moving. 224 00:13:24,640 --> 00:13:29,160 You've successfully discovered that the Earth goes around the sun? We proved it, yes. Yep. 225 00:13:29,160 --> 00:13:34,280 So, you had one of these things. Yeah. Erm...what happened next? 226 00:13:34,280 --> 00:13:37,160 It was about a month after we'd found the first one, 227 00:13:37,160 --> 00:13:40,280 we had a meeting to discuss how to publish this. 228 00:13:40,280 --> 00:13:45,200 It was a real problem when you've got one example of a crazy result. 229 00:13:47,120 --> 00:13:50,880 And I remember that meeting because that night, looking at 230 00:13:50,880 --> 00:13:53,760 some chart recordings from a totally different bit of sky, 231 00:13:53,760 --> 00:13:57,640 saw a quarter inch of suspicious looking signal, 232 00:13:57,640 --> 00:14:00,720 pulse, pulse, pulse, pulse, 233 00:14:00,720 --> 00:14:04,160 this time one-and-a-quarter seconds apart. 234 00:14:04,160 --> 00:14:07,000 But, clearly, the same kind of thing, same family, 235 00:14:07,000 --> 00:14:09,080 totally different bit of the sky. 236 00:14:09,080 --> 00:14:12,000 And that... that was the eureka moment. 237 00:14:12,000 --> 00:14:14,920 The first one was just too darn worrying. 238 00:14:14,920 --> 00:14:19,000 These things turned out to be what we now call pulsars. Yep. 239 00:14:19,000 --> 00:14:22,120 So what do we know about pulsars? What are they? 240 00:14:22,120 --> 00:14:27,800 They're formed in supernova explosions. Part of that explosion 241 00:14:27,800 --> 00:14:29,760 is that collapse of the core. 242 00:14:29,760 --> 00:14:32,800 And a pulsar is a collapsed core, 243 00:14:32,800 --> 00:14:35,200 weighing about the same as the sun 244 00:14:35,200 --> 00:14:38,360 but it's all squashed into a ball about ten miles across, 245 00:14:38,360 --> 00:14:40,560 so really dense. 246 00:14:40,560 --> 00:14:45,160 My analogy for the density of a pulsar is you take a sewing thimble, 247 00:14:45,160 --> 00:14:47,880 you take the population of the globe, 248 00:14:47,880 --> 00:14:53,120 you jam the seven billion people, one by one... Carefully. Hard! 249 00:14:53,120 --> 00:14:55,800 ..into this thimble. 250 00:14:55,800 --> 00:14:59,040 And when you've got it fool of seven billion people, squashed, 251 00:14:59,040 --> 00:15:02,680 it weighs the same as if it were made of pulsar material. 252 00:15:02,680 --> 00:15:05,080 So, it's really dense stuff. 253 00:15:05,080 --> 00:15:08,320 And the whole thing spins incredibly fast. 254 00:15:08,320 --> 00:15:13,000 Some of these things are spinning 700 times a second. Really fast. 255 00:15:13,000 --> 00:15:17,920 Scarily fast. We see these as these very rapid pulsations. Yes. 256 00:15:17,920 --> 00:15:19,640 And, incredibly regularly. 257 00:15:19,640 --> 00:15:25,560 Because when you get 1,000 million million million million tonnes of stuff spinning, 258 00:15:25,560 --> 00:15:28,280 it's very hard to make it change its spin. 259 00:15:28,280 --> 00:15:32,920 So, it's a clock. And indeed, we make use of that these days. 260 00:15:32,920 --> 00:15:36,440 These things are clocks out in the galaxy and we use them 261 00:15:36,440 --> 00:15:38,880 to check out Einstein's relativity. 262 00:15:38,880 --> 00:15:41,080 We should talk about another mystery, 263 00:15:41,080 --> 00:15:43,960 something that has been bothering radios astronomers recently. 264 00:15:43,960 --> 00:15:47,960 These things called fast radio bursts. What do we know about that? 265 00:15:47,960 --> 00:15:49,600 Not a lot. 266 00:15:49,600 --> 00:15:52,720 They've been picked up by the pulsar people 267 00:15:52,720 --> 00:15:57,200 because they are short, sharp pulses, and pretty strong. 268 00:15:57,200 --> 00:15:59,520 And I think the first thought was, 269 00:15:59,520 --> 00:16:02,760 "Oh, this is freakishly large pulse from a pulsar." 270 00:16:02,760 --> 00:16:06,680 But, actually, nothing ever comes from that bit of space again. 271 00:16:06,680 --> 00:16:10,440 For one of them, they had another eight telescopes 272 00:16:10,440 --> 00:16:13,360 quickly slewed to the position, X-ray telescopes, 273 00:16:13,360 --> 00:16:16,360 optical telescopes and more radio telescopes. 274 00:16:16,360 --> 00:16:20,080 There's nothing to be seen after the bust has happened. 275 00:16:20,080 --> 00:16:22,720 So, there's a whfft! And that is it. 276 00:16:22,720 --> 00:16:25,120 It's fun we're still finding these things. Isn't it? 277 00:16:25,120 --> 00:16:27,360 And I think there will be more, 278 00:16:27,360 --> 00:16:31,720 as we do more of this short time duration transient astronomy 279 00:16:31,720 --> 00:16:34,760 which astronomers really are only getting into now. 280 00:16:34,760 --> 00:16:36,560 It is just beginning. 281 00:16:42,160 --> 00:16:45,040 To find out more about fast radio bursts 282 00:16:45,040 --> 00:16:47,320 and how astronomers are trying to find them, 283 00:16:47,320 --> 00:16:51,960 check out our website at bbc.co.uk/skyatnight. 284 00:16:53,920 --> 00:16:57,800 In a few moments, we'll turn from aliens travelling to visit us 285 00:16:57,800 --> 00:17:01,880 to the problems we humans have exploring our own solar system, 286 00:17:01,880 --> 00:17:05,600 as we look at Britain's attempt to visit Mars with Beagle 2. 287 00:17:05,600 --> 00:17:07,920 But first, Pete Lawrence is here to show us 288 00:17:07,920 --> 00:17:11,040 how easy it is to find UFOs. 289 00:17:11,040 --> 00:17:13,040 There are all sorts of things up in the sky 290 00:17:13,040 --> 00:17:15,240 which try and trick us into thinking that 291 00:17:15,240 --> 00:17:17,200 aliens visiting from other worlds. 292 00:17:17,200 --> 00:17:20,040 And I want to show you what some of these things are. 293 00:17:22,640 --> 00:17:26,360 Ours skies are populated with objects that, at first glance, 294 00:17:26,360 --> 00:17:30,640 look like they're straight out of a science fiction film. 295 00:17:30,640 --> 00:17:32,960 One of the most common are clouds. 296 00:17:35,320 --> 00:17:37,720 Some clouds look really otherworldly. 297 00:17:37,720 --> 00:17:40,600 Just look at this amazing image back here. 298 00:17:40,600 --> 00:17:43,160 Now, these are what are known as lenticular clouds 299 00:17:43,160 --> 00:17:47,000 and this particular photograph was taken from Halifax in the UK. 300 00:17:47,000 --> 00:17:50,840 But, typically, lenticular clouds form over mountainous regions 301 00:17:50,840 --> 00:17:54,120 where the weather is warm, moist and stable. 302 00:17:54,120 --> 00:17:57,960 But there are even stranger clouds than this. 303 00:17:57,960 --> 00:18:01,040 This bizarre gap in the cloud is called a "fall streak hole" 304 00:18:01,040 --> 00:18:05,040 or "hole punch cloud" and it occurs when something happens 305 00:18:05,040 --> 00:18:08,160 to cause ice crystals to form right in the centre. 306 00:18:08,160 --> 00:18:12,000 They fall out of the sky, leaving behind this amazing hole. 307 00:18:13,720 --> 00:18:17,000 Of course, some UFO sightings are actually space-based. 308 00:18:18,120 --> 00:18:23,080 Many people mistake satellites for either planes or shooting stars. 309 00:18:23,080 --> 00:18:25,600 But sometimes, when the conditions are just right, 310 00:18:25,600 --> 00:18:28,080 they can look really spectacular. 311 00:18:28,080 --> 00:18:31,080 This is what's known as an iridium flare. 312 00:18:31,080 --> 00:18:33,600 What you're seeing is sunlight reflected off flat 313 00:18:33,600 --> 00:18:36,160 surfaces on the satellite's body. 314 00:18:36,160 --> 00:18:39,480 It's so UFO-like because the light appears from nowhere 315 00:18:39,480 --> 00:18:42,480 and then just vanishes away. 316 00:18:42,480 --> 00:18:44,800 Most are predictable, and if you go onto our website 317 00:18:44,800 --> 00:18:48,960 there's a link there to help you find out how to see a flare for yourself. 318 00:18:50,360 --> 00:18:53,600 But there are stranger appearances still. 319 00:18:53,600 --> 00:18:57,320 From time to time, rockets carrying spacecraft into orbit 320 00:18:57,320 --> 00:19:00,760 dump fuel, and this can create a bizarre and mysterious 321 00:19:00,760 --> 00:19:03,600 glowing shape, which is visible in the night sky. 322 00:19:05,400 --> 00:19:07,440 And then there's this. 323 00:19:07,440 --> 00:19:10,880 This image was taken from northern Norway in 2009, 324 00:19:10,880 --> 00:19:12,440 and it's not a manipulated image. 325 00:19:12,440 --> 00:19:15,440 This is actually what was seen in the sky. 326 00:19:15,440 --> 00:19:17,360 Hard to believe as it may be, 327 00:19:17,360 --> 00:19:20,520 this was the result of a Russian missile test. 328 00:19:20,520 --> 00:19:25,120 The rocket malfunctioned, leaking a trail of fuel as it spun. 329 00:19:25,120 --> 00:19:28,120 But the other factor was the time of day. 330 00:19:28,120 --> 00:19:30,600 For the photographer, the sun was below the horizon, 331 00:19:30,600 --> 00:19:33,520 but up in the upper atmosphere, the sunlight was able to 332 00:19:33,520 --> 00:19:37,080 illuminate the released fuel, creating this spooky effect. 333 00:19:38,600 --> 00:19:42,080 Finally, the celestial object that's mostly like to be confused 334 00:19:42,080 --> 00:19:44,520 with a UFO has to be the planet Venus. 335 00:19:45,600 --> 00:19:47,520 Though it might sound strange to think 336 00:19:47,520 --> 00:19:50,240 you could mistake a planet for a flying object, 337 00:19:50,240 --> 00:19:53,360 but Venus certainly seems to be able to pull off this trick. 338 00:19:53,360 --> 00:19:56,760 And there are apocryphal tales of pilots seeing Venus 339 00:19:56,760 --> 00:19:58,920 and thinking it's an oncoming aircraft. 340 00:20:05,600 --> 00:20:08,160 And now, to the news from Mars. 341 00:20:08,160 --> 00:20:12,320 Beagle 2, the UK's first and only attempt at a Mars lander 342 00:20:12,320 --> 00:20:16,200 has been missing, presumed destroyed, for over 11 years. 343 00:20:16,200 --> 00:20:19,440 But now, a team using images from NASA's remarkable 344 00:20:19,440 --> 00:20:21,080 Mars Reconnaissance Orbiter 345 00:20:21,080 --> 00:20:24,600 think they've seen signs of Beagle safe on the surface. 346 00:20:24,600 --> 00:20:26,800 We'll be finding out what this means for the mission 347 00:20:26,800 --> 00:20:28,000 in just a few moments. 348 00:20:28,000 --> 00:20:31,200 But first, lets remind ourselves of the Beagle story 349 00:20:31,200 --> 00:20:33,560 and what happened over Christmas in 2003. 350 00:20:35,800 --> 00:20:40,240 Beagle 2 was designed to sample the surface of Mars. 351 00:20:40,240 --> 00:20:43,080 The lander was the brainchild of Colin Pillinger 352 00:20:43,080 --> 00:20:45,360 who believed passionately that Beagle could 353 00:20:45,360 --> 00:20:47,040 answer the big question - 354 00:20:47,040 --> 00:20:49,640 whether there was life on the red planet. 355 00:20:49,640 --> 00:20:50,880 There is every chance 356 00:20:50,880 --> 00:20:52,840 that there could be a niche on Mars 357 00:20:52,840 --> 00:20:55,000 where there is some kind of life. 358 00:20:55,000 --> 00:20:58,560 That's what Beagle intends to do, analyse the atmosphere, 359 00:20:58,560 --> 00:21:02,480 see if there is a trace of methane in the atmosphere, 360 00:21:02,480 --> 00:21:05,240 because if there is, it shouldn't be there 361 00:21:05,240 --> 00:21:07,960 unless there's biology constantly producing it. 362 00:21:09,720 --> 00:21:14,240 Beagle 2 was carried to Mars on board ESA's Mars Express. 363 00:21:14,240 --> 00:21:17,160 But strict weight restrictions and a firm deadline 364 00:21:17,160 --> 00:21:22,240 meant the tiny probe had to rely on a novel, and untested, landing system. 365 00:21:22,240 --> 00:21:25,160 It involved using a series of parachutes to slow 366 00:21:25,160 --> 00:21:28,080 the spacecraft in Mars's thin atmosphere, 367 00:21:28,080 --> 00:21:32,200 and then hoping the air bags could cushion its impact. 368 00:21:32,200 --> 00:21:34,920 The mission captured the public imagination. 369 00:21:34,920 --> 00:21:38,800 Cultural icons Blur recorded a call sign to be played when Beagle 370 00:21:38,800 --> 00:21:41,400 woke up and Damien Hirst got involved, 371 00:21:41,400 --> 00:21:43,640 designing the colour calibration card. 372 00:21:46,120 --> 00:21:50,960 In late December 2003, Beagle 2 began its treacherous decent, 373 00:21:50,960 --> 00:21:55,360 with touchdown scheduled for early on Christmas Day. 374 00:21:55,360 --> 00:21:59,280 Colin and his team waited for the landing signal to come back, 375 00:21:59,280 --> 00:22:01,360 but none was received. 376 00:22:01,360 --> 00:22:05,000 On this mission, our faith has been unshakable that the mission 377 00:22:05,000 --> 00:22:08,440 would go ahead, and we've crossed lots of bridges to get this far. 378 00:22:08,440 --> 00:22:13,160 So, we'll keep the unshakable faith until the point comes 379 00:22:13,160 --> 00:22:17,160 when we have to say it's no longer worth thinking about. 380 00:22:17,160 --> 00:22:20,640 Despite weeks of trying, contact was never established 381 00:22:20,640 --> 00:22:22,800 with the little spacecraft. 382 00:22:22,800 --> 00:22:25,280 The mission was branded a failure. 383 00:22:25,280 --> 00:22:28,600 ESA concluded that the landing system probably didn't work 384 00:22:28,600 --> 00:22:31,920 and that Beagle 2 crashed into the surface. 385 00:22:31,920 --> 00:22:36,040 But Pillinger, the eternal optimist, didn't agree. 386 00:22:36,040 --> 00:22:38,440 I never, ever believed that we'd crashed, 387 00:22:38,440 --> 00:22:41,960 and I certainly, probably, don't now. 388 00:22:41,960 --> 00:22:44,920 Sadly, Colin never lived to discover what happened 389 00:22:44,920 --> 00:22:46,480 to his spacecraft. 390 00:22:46,480 --> 00:22:48,400 He died in May last year. 391 00:22:50,120 --> 00:22:52,560 But now, we know. 392 00:22:52,560 --> 00:22:55,320 The latest images from Mars suggest that Beagle 393 00:22:55,320 --> 00:22:58,680 came closer to success than almost anyone had thought. 394 00:22:58,680 --> 00:23:02,840 And Maggie's talking to Jim Clemmet who worked on the Beagle team. 395 00:23:02,840 --> 00:23:05,840 It's 11 years since Beagle 2 disappeared. 396 00:23:05,840 --> 00:23:07,680 How come we've found it now? 397 00:23:07,680 --> 00:23:08,800 A high resolution camera 398 00:23:08,800 --> 00:23:10,760 on Mars Reconnaissance Orbiter has, 399 00:23:10,760 --> 00:23:11,840 over the years, 400 00:23:11,840 --> 00:23:13,520 been taking images of Mars, 401 00:23:13,520 --> 00:23:16,240 including about 11 or 12, 402 00:23:16,240 --> 00:23:18,520 overlapped across the landing ellipse of Beagle 2. 403 00:23:18,520 --> 00:23:20,280 And a number of those images are showing 404 00:23:20,280 --> 00:23:23,400 an artefact on the surface of Mars. 405 00:23:23,400 --> 00:23:27,080 The images appear to show a number of objects that scientists 406 00:23:27,080 --> 00:23:31,280 believe were the rear cover, parachute and the lander itself. 407 00:23:33,000 --> 00:23:35,360 Even though it's just a few pixels wide, 408 00:23:35,360 --> 00:23:40,480 closer views appear to reveal the telltale shape of Beagle 2, 409 00:23:40,480 --> 00:23:45,360 and suggest that the spacecraft had begun to deploy its solar panels. 410 00:23:45,360 --> 00:23:47,720 So, this is the first panel to come out, 411 00:23:47,720 --> 00:23:51,920 and this is covered, about 80%, with solar cells, which are glass. 412 00:23:51,920 --> 00:23:53,920 So, very reflective. Very reflective. 413 00:23:53,920 --> 00:23:57,160 And then the next panel would be this one. 414 00:23:57,160 --> 00:24:00,240 And we think we're looking at something like that. 415 00:24:00,240 --> 00:24:01,600 'And if this the case, 416 00:24:01,600 --> 00:24:05,800 'it radically changes our view of the mission's success.' 417 00:24:05,800 --> 00:24:09,320 Well, it means that the entering descent and landing system worked. 418 00:24:09,320 --> 00:24:13,280 That the lander survived impact onto the surface. 419 00:24:13,280 --> 00:24:15,360 That all the electronics absorbed that shock. 420 00:24:15,360 --> 00:24:18,280 'So, Beagle 2 was not lost after all. 421 00:24:18,280 --> 00:24:20,880 'Not only did it successfully touchdown on Mars, 422 00:24:20,880 --> 00:24:23,520 'it also began to operate. 423 00:24:23,520 --> 00:24:27,080 'So, why have we heard nothing for over a decade?' 424 00:24:27,080 --> 00:24:29,200 If we open these up now, you will see. 425 00:24:29,200 --> 00:24:35,440 So, underneath here is the antenna. A-ha. Yes. 426 00:24:35,440 --> 00:24:38,880 OK, so, if all the panels had opened up, as we see now, 427 00:24:38,880 --> 00:24:41,120 then the antenna would have been free to communicate 428 00:24:41,120 --> 00:24:43,760 and then the mission would have been able to proceed. 429 00:24:43,760 --> 00:24:46,760 And so, whilst we know where Beagle is now, 430 00:24:46,760 --> 00:24:50,720 there's no means of trying to restart it. 431 00:24:50,720 --> 00:24:53,880 So, there's no way of communicating with it. Yes. 432 00:24:53,880 --> 00:24:58,040 'Even so, Beagle 2 still has a hold on us.' 433 00:24:58,040 --> 00:25:01,720 There are other parts of the Beagle mission that were also a success. 434 00:25:01,720 --> 00:25:04,960 For example, encouraging young people into science, 435 00:25:04,960 --> 00:25:06,560 technology, engineering. 436 00:25:06,560 --> 00:25:10,760 And I know there are people out there now who are engineers or 437 00:25:10,760 --> 00:25:12,120 scientists because of Beagle. 438 00:25:13,800 --> 00:25:17,920 'Perhaps the late Colin Pillinger summed it up best.' 439 00:25:17,920 --> 00:25:20,160 It was not a failure. 440 00:25:20,160 --> 00:25:22,000 Deferred success. 441 00:25:22,000 --> 00:25:23,240 Triumph, not disaster. 442 00:25:29,840 --> 00:25:32,560 Now, back to all things UFO. 443 00:25:32,560 --> 00:25:34,560 And if we're serious about finding aliens, 444 00:25:34,560 --> 00:25:36,560 we don't have to wait for them to come to us. 445 00:25:36,560 --> 00:25:38,880 We can look for them. 446 00:25:38,880 --> 00:25:41,480 Here at Jodrell Bank, they're working on a system 447 00:25:41,480 --> 00:25:43,720 that will allow them to use their radio telescopes, 448 00:25:43,720 --> 00:25:45,800 not to look for flying saucers, 449 00:25:45,800 --> 00:25:49,760 but to search for signals from alien civilisations out in space. 450 00:25:51,600 --> 00:25:54,920 The question is, what would that signal look like? 451 00:25:54,920 --> 00:25:58,480 A regular pulse would be a good clue that the signal was artificial, 452 00:25:58,480 --> 00:26:01,320 but we now know that's how pulsars appear. 453 00:26:01,320 --> 00:26:04,480 And so the team at Jodrell are taking a different approach. 454 00:26:04,480 --> 00:26:06,960 They want to hunt for radio emission that's confined 455 00:26:06,960 --> 00:26:09,160 to such a narrow frequency range, 456 00:26:09,160 --> 00:26:12,040 that they have to be artificial. 457 00:26:12,040 --> 00:26:15,440 This is the live data coming in now off one of the telescopes. 458 00:26:15,440 --> 00:26:17,240 So, what you're seeing, basically, 459 00:26:17,240 --> 00:26:19,320 is this is frequency in the radio spectrum. 460 00:26:19,320 --> 00:26:20,840 Like tuning your radio at home? 461 00:26:20,840 --> 00:26:22,040 You could tune to different 462 00:26:22,040 --> 00:26:23,240 frequencies along here. 463 00:26:23,240 --> 00:26:25,000 So, there are signals there? Yeah. 464 00:26:25,000 --> 00:26:26,560 So, that's it - aliens? We're done. 465 00:26:26,560 --> 00:26:28,480 You know, people are communicating with us. 466 00:26:28,480 --> 00:26:30,960 If it was easy as that, that would be great! 467 00:26:30,960 --> 00:26:33,600 So, what you've got to do is tell the difference between 468 00:26:33,600 --> 00:26:35,720 things that are natural sources of radio emission 469 00:26:35,720 --> 00:26:37,360 and artificial sources. 470 00:26:37,360 --> 00:26:39,640 So, we'd assume the aliens are producing some 471 00:26:39,640 --> 00:26:41,760 sort of artificial radio emission. Sure. 472 00:26:43,440 --> 00:26:46,720 Natural sources of radio emission, like stars or planets, 473 00:26:46,720 --> 00:26:49,520 should emit across a broad range of frequencies. 474 00:26:49,520 --> 00:26:53,240 And that's what the Jodrell radio telescopes are used to picking up. 475 00:26:53,240 --> 00:26:57,200 But within this broad spectrum, there might just be a hidden signal. 476 00:26:57,200 --> 00:27:00,160 And so, whilst the radio telescopes are scanning the sky 477 00:27:00,160 --> 00:27:01,960 looking for everyday phenomena, 478 00:27:01,960 --> 00:27:04,960 Tim is going to use the supercomputer here at Jodrell 479 00:27:04,960 --> 00:27:07,600 to scan data that's normally thrown away, 480 00:27:07,600 --> 00:27:10,040 hoping to find that telltale signal. 481 00:27:12,880 --> 00:27:15,600 What you'd be looking for is a sort of spike 482 00:27:15,600 --> 00:27:17,800 rising and falling in strength, 483 00:27:17,800 --> 00:27:21,240 and that would be like an on-off message, if you like. 484 00:27:21,240 --> 00:27:24,040 Or perhaps it drifts in frequency, because of... 485 00:27:24,040 --> 00:27:26,960 If it's coming from a planet, that planet could be orbiting a star 486 00:27:26,960 --> 00:27:29,120 and that would give this regular Doppler shift. 487 00:27:29,120 --> 00:27:32,600 'But it's like looking for the proverbial needle in a haystack.' 488 00:27:32,600 --> 00:27:34,560 If we go back to the earliest days of SETI, 489 00:27:34,560 --> 00:27:37,080 there was this paper produced by two guys, 490 00:27:37,080 --> 00:27:39,320 Cocconi and Morrison. There was a good line in there 491 00:27:39,320 --> 00:27:41,760 that really summarises the whole thing for SETI 492 00:27:41,760 --> 00:27:44,240 which is that, "The probability of success 493 00:27:44,240 --> 00:27:46,960 "is difficult to estimate, but if we never search, 494 00:27:46,960 --> 00:27:48,960 "the chance of success is zero." 495 00:27:48,960 --> 00:27:51,200 Well, call us if the new programme finds something. 496 00:27:51,200 --> 00:27:52,920 We will do, yeah. Good stuff. Good luck. 497 00:27:54,400 --> 00:27:55,760 That's it for this programme 498 00:27:55,760 --> 00:27:57,600 and next month we take a break. 499 00:27:57,600 --> 00:27:59,840 Instead, standing in this very spot, 500 00:27:59,840 --> 00:28:01,680 will be Brain Cox and Dara O Briain 501 00:28:01,680 --> 00:28:03,600 with the return of Stargazing Live. 502 00:28:03,600 --> 00:28:05,760 They've got a packed series of programmes. 503 00:28:05,760 --> 00:28:07,440 I'll be there hunting supernovae, 504 00:28:07,440 --> 00:28:09,720 but the true highlight will be the solar eclipse 505 00:28:09,720 --> 00:28:14,040 that sweeps across the UK on the morning of March 20th. 506 00:28:14,040 --> 00:28:16,520 For most of us, it will be a partial eclipse. 507 00:28:16,520 --> 00:28:19,480 But the Stargazing Live team are heading north to the Faroe Islands, 508 00:28:19,480 --> 00:28:23,840 so that we can all witness the majesty of a total eclipse. 509 00:28:23,840 --> 00:28:26,440 We return after Easter, on 12th April, 510 00:28:26,440 --> 00:28:29,680 celebrating 25 years of the Hubble Space telescope. 511 00:28:29,680 --> 00:28:32,120 So, in the meantime, get outside 512 00:28:32,120 --> 00:28:34,360 and get looking up. Goodnight.