1 00:00:02,200 --> 00:00:07,200 THEME MUSIC: "At The Castle Gate" from "Pelleas and Melisande Suite" by Jean Sibelius. 2 00:00:26,000 --> 00:00:28,200 Welcome to the Royal Observatory Greenwich, 3 00:00:28,200 --> 00:00:30,240 the historical home of British astronomy 4 00:00:30,240 --> 00:00:33,480 and a place with a surprising link to this month's topic. 5 00:00:33,480 --> 00:00:35,920 The big story at the moment in our night skies, 6 00:00:35,920 --> 00:00:38,840 is the fifth planet of the solar system, the mighty Jupiter. 7 00:00:38,840 --> 00:00:41,800 And that's what we're going to explore in this programme. 8 00:00:41,800 --> 00:00:45,240 Coming up, physicist Helen Czerski will be trying to uncover 9 00:00:45,240 --> 00:00:48,680 some of the mysteries of Jupiter's atmosphere. 10 00:00:48,680 --> 00:00:50,520 The memorable thing about the Great Red Spot 11 00:00:50,520 --> 00:00:51,840 is it's been there for so long. 12 00:00:51,840 --> 00:00:54,840 These features will persist for as long as the experiment runs. 13 00:00:54,840 --> 00:00:57,120 Pete Lawrence will be showing us 14 00:00:57,120 --> 00:01:01,240 just how easy it is for anyone to get a great view of Jupiter. 15 00:01:01,240 --> 00:01:04,680 We'll be finding out about an astonishing new discovery, 16 00:01:04,680 --> 00:01:08,200 water spraying out from one of Jupiter's moons. 17 00:01:08,200 --> 00:01:12,200 We're talking about a plume of water 200km high 18 00:01:12,200 --> 00:01:13,920 over the south pole of Europa. 19 00:01:13,920 --> 00:01:15,920 And how the pictures you take 20 00:01:15,920 --> 00:01:19,560 could be an essential tool in the study of the gas giant. 21 00:01:22,520 --> 00:01:26,040 Jupiter is always a wonderful object to see in the night sky 22 00:01:26,040 --> 00:01:29,080 but right now it's truly spectacular, outshining 23 00:01:29,080 --> 00:01:30,920 even the brightest stars. 24 00:01:30,920 --> 00:01:34,480 For the next few months, it'll be high in the sky after sunset 25 00:01:34,480 --> 00:01:37,640 making this the best opportunity for British observers to get 26 00:01:37,640 --> 00:01:39,800 a look at this fascinating world. 27 00:01:39,800 --> 00:01:43,960 One of the joys of observing Jupiter is seeing those distinctive bands 28 00:01:43,960 --> 00:01:45,520 and, of course, the Red Spot. 29 00:01:45,520 --> 00:01:47,600 This image shows that in amazing detail. 30 00:01:47,600 --> 00:01:49,560 Now the bands are actually formed by 31 00:01:49,560 --> 00:01:51,120 a weather system which goes all 32 00:01:51,120 --> 00:01:55,440 the way round Jupiter, with wind speeds greater than 300mph. 33 00:01:55,440 --> 00:01:58,880 The Great Red Spot is actually three times the size of planet Earth 34 00:01:58,880 --> 00:02:01,680 and has been raging for over three centuries. 35 00:02:01,680 --> 00:02:04,080 And it's to this amazing weather that we turn first. 36 00:02:04,080 --> 00:02:06,280 We sent physicist Helen Czerski 37 00:02:06,280 --> 00:02:10,120 to see she could find out what causes this magnificent display. 38 00:02:15,240 --> 00:02:18,640 When you look at an image of Jupiter, the most obvious thing are these 39 00:02:18,640 --> 00:02:22,760 fabulous bands of colour that go horizontally across the surface. 40 00:02:22,760 --> 00:02:25,200 But Jupiter doesn't really have a surface as such 41 00:02:25,200 --> 00:02:26,640 because it's a gas giant. 42 00:02:26,640 --> 00:02:32,520 What you see on Jupiter are swirling clouds of many different gases, 43 00:02:32,520 --> 00:02:34,960 effectively what we're looking at 44 00:02:34,960 --> 00:02:38,240 are just the tops of complex weather patterns. 45 00:02:38,240 --> 00:02:41,840 But what drives this violent and long-lasting weather? 46 00:02:41,840 --> 00:02:44,080 You'd think that - you can see so much detail - 47 00:02:44,080 --> 00:02:46,600 the answer must be obvious but actually this is 48 00:02:46,600 --> 00:02:49,160 one of the biggest mysteries in the Solar System. 49 00:02:49,160 --> 00:02:53,320 One of the clearest features we can see from Earth is that 50 00:02:53,320 --> 00:02:57,960 the atmosphere is arranged in a series of bands circling the planet. 51 00:02:57,960 --> 00:02:59,320 These bands are iconic, 52 00:02:59,320 --> 00:03:02,400 really strongly associated with Jupiter, 53 00:03:02,400 --> 00:03:07,840 but this isn't the only planet to have weather in bands like this. 54 00:03:07,840 --> 00:03:11,480 Saturn has clearly defined stripes of light and shade. 55 00:03:11,480 --> 00:03:15,360 Neptune also has subtle visible bands. 56 00:03:16,600 --> 00:03:19,040 The bands of weather that we are most familiar with 57 00:03:19,040 --> 00:03:21,920 are actually here on Earth, it's just that we can't see them 58 00:03:21,920 --> 00:03:23,920 because our atmosphere is transparent. 59 00:03:23,920 --> 00:03:26,520 But they are there. 60 00:03:26,520 --> 00:03:29,840 Earth's atmosphere is actually divided into distinct regions 61 00:03:29,840 --> 00:03:31,560 known as cells. 62 00:03:31,560 --> 00:03:35,640 Each cell is driven by hot air rising high into the atmosphere 63 00:03:35,640 --> 00:03:38,480 and flowing either north or south. 64 00:03:38,480 --> 00:03:39,840 There are six in total. 65 00:03:41,240 --> 00:03:43,880 And the thing that I like about the comparison between Earth 66 00:03:43,880 --> 00:03:49,360 and Jupiter is that we can't see those bands, those cells, 67 00:03:49,360 --> 00:03:53,360 on Earth, but on Jupiter they are really visible. 68 00:03:54,760 --> 00:03:59,640 Jupiter has many more cells than we have on Earth, there are at least 12. 69 00:04:00,840 --> 00:04:04,160 And that's not just because it's bigger, the number of cells 70 00:04:04,160 --> 00:04:08,080 a planet has actually depends on how quickly it's rotating. 71 00:04:09,400 --> 00:04:14,480 Earth rotates once every 24 hours, that's what defines a day. 72 00:04:14,480 --> 00:04:19,040 But Jupiter rotates roughly once every 10 hours, over twice as fast, 73 00:04:19,040 --> 00:04:23,000 and if Earth did the same, our weather would be very different. 74 00:04:24,440 --> 00:04:26,720 This is a simulation of the Earth as it is now, 75 00:04:26,720 --> 00:04:29,520 looking slightly down from the northern hemisphere. 76 00:04:29,520 --> 00:04:32,480 So the planet is rotating this way around. 77 00:04:32,480 --> 00:04:37,120 What the colours represent are wind speeds high up in the atmosphere. 78 00:04:37,120 --> 00:04:41,080 But if we change the simulation, so we speed up the rotation speed of the 79 00:04:41,080 --> 00:04:46,160 Earth by a factor of four, a six-hour day, this is what it looks like. 80 00:04:46,160 --> 00:04:48,800 You can see that suddenly there are many more bands 81 00:04:48,800 --> 00:04:50,520 stretching around the planet. 82 00:04:50,520 --> 00:04:54,120 The winds are constantly being pulled in a lateral direction, and that 83 00:04:54,120 --> 00:04:57,960 means it's really hard for currents from the north and the south to form. 84 00:04:57,960 --> 00:05:01,000 So the structure of Jupiter's atmosphere 85 00:05:01,000 --> 00:05:05,240 is locked in these bands that we're all so familiar with. 86 00:05:05,240 --> 00:05:08,200 The bands of fast-moving winds aren't the only 87 00:05:08,200 --> 00:05:10,400 weather we can see on Jupiter, 88 00:05:10,400 --> 00:05:13,960 there are also extraordinary vortices and spots, 89 00:05:13,960 --> 00:05:16,600 some of which last for centuries. 90 00:05:17,760 --> 00:05:21,320 But why did these atmospheric storms last so long? 91 00:05:22,720 --> 00:05:26,760 I'm meeting Professor Peter Read, who is using a jug of water, 92 00:05:26,760 --> 00:05:28,000 some sparkling dye 93 00:05:28,000 --> 00:05:33,160 and a rotating rig to recreate a section of Jupiter's atmosphere. 94 00:05:33,160 --> 00:05:35,680 Jupiter is quite unlike the Earth in many respects. 95 00:05:35,680 --> 00:05:37,560 And in one important respect, 96 00:05:37,560 --> 00:05:40,040 and that is that on the Earth, the equator is usually hot 97 00:05:40,040 --> 00:05:42,320 and the poles are cold, 98 00:05:42,320 --> 00:05:44,480 on Jupiter that's not the case. 99 00:05:44,480 --> 00:05:47,520 What we tend to see is that the main temperature differences that we can 100 00:05:47,520 --> 00:05:50,280 measure in the atmosphere are actually between the bright bands 101 00:05:50,280 --> 00:05:52,600 and the dark bands. You will typically have 102 00:05:52,600 --> 00:05:54,640 a bright band, which is relatively warm, 103 00:05:54,640 --> 00:05:57,120 and then, to the north and the south of that, 104 00:05:57,120 --> 00:06:00,000 there will be a dark band that is relatively cold. 105 00:06:00,000 --> 00:06:03,040 That sounds amazing to me because I'm used to thinking about the Earth, 106 00:06:03,040 --> 00:06:05,800 and the idea that the equator is hotter and the poles are cooler 107 00:06:05,800 --> 00:06:07,520 is such a strong idea and that drives 108 00:06:07,520 --> 00:06:10,720 all of our weather on this planet, but Jupiter is quite different. 109 00:06:10,720 --> 00:06:13,880 And Jupiter has an extra ingredient that the Earth doesn't have and that 110 00:06:13,880 --> 00:06:18,880 is that Jupiter itself is a source of energy from its deep interior. 111 00:06:18,880 --> 00:06:22,320 It actually generates almost as much energy from 112 00:06:22,320 --> 00:06:25,040 its deep interior as it receives on average from the sun. 113 00:06:25,040 --> 00:06:28,560 With this experiment, we're trying to create a simulation of 114 00:06:28,560 --> 00:06:31,880 what happens within one of Jupiter's bands. 115 00:06:31,880 --> 00:06:34,040 The water is heated but the edges 116 00:06:34,040 --> 00:06:36,640 in the centre of the vessel are cooled, 117 00:06:36,640 --> 00:06:40,440 this represents a warm band on Jupiter surrounded by 118 00:06:40,440 --> 00:06:43,920 colder air, and then the whole experimented is rotated. 119 00:06:45,000 --> 00:06:48,200 After a few minutes, some vortices are created that are 120 00:06:48,200 --> 00:06:51,160 so stable they barely appear to move. 121 00:06:53,120 --> 00:06:57,080 So what you can see in now is a whole chain of these eddies 122 00:06:57,080 --> 00:06:59,600 that are circulating in the same sense. 123 00:06:59,600 --> 00:07:01,600 So if this was a band on Jupiter, 124 00:07:01,600 --> 00:07:04,800 at the bottom of the band the winds are going this way round 125 00:07:04,800 --> 00:07:07,520 and then you've got these eddies spinning like this, 126 00:07:07,520 --> 00:07:11,400 but at the top, the winds are going the other way. That's right. 127 00:07:11,400 --> 00:07:14,320 So this is just like the bright bands on Jupiter. 128 00:07:14,320 --> 00:07:16,880 So in the south, the jets will be going in one direction, 129 00:07:16,880 --> 00:07:19,680 and to the north, they'll be going in the opposite direction 130 00:07:19,680 --> 00:07:21,640 with these vortices rolling in between them. 131 00:07:21,640 --> 00:07:26,160 These rotating storms are trapped within the bands that have been 132 00:07:26,160 --> 00:07:28,360 created by Jupiter's fast rotation. 133 00:07:29,480 --> 00:07:32,440 This means they are remarkably stable. 134 00:07:32,440 --> 00:07:34,880 On Earth, storms come and go, but on Jupiter 135 00:07:34,880 --> 00:07:37,040 the really memorable thing about Great Red Spot 136 00:07:37,040 --> 00:07:38,440 is it's been there for so long. 137 00:07:38,440 --> 00:07:40,240 These little storms you've generated 138 00:07:40,240 --> 00:07:42,080 in this experiment are just persisting. 139 00:07:42,080 --> 00:07:43,520 These features will persist 140 00:07:43,520 --> 00:07:45,840 for as long as we keep the experiment running, 141 00:07:45,840 --> 00:07:47,720 once the whole thing has settled down. 142 00:07:47,720 --> 00:07:50,720 This is just a two-dimensional representation 143 00:07:50,720 --> 00:07:53,120 of what might be happening on Jupiter, 144 00:07:53,120 --> 00:07:56,080 but our knowledge doesn't go much beyond that. 145 00:07:56,080 --> 00:07:58,560 The problem is that when we look at the planet, 146 00:07:58,560 --> 00:08:00,360 all we can see are the tops of the clouds 147 00:08:00,360 --> 00:08:03,200 and it's really difficult to measure what's underneath that. 148 00:08:04,640 --> 00:08:07,840 Finding out what's happening deep within the planet 149 00:08:07,840 --> 00:08:09,600 is the next great challenge. 150 00:08:12,920 --> 00:08:15,520 Luckily, there's hope that we all resolve some of these 151 00:08:15,520 --> 00:08:17,760 unanswered questions in the near future 152 00:08:17,760 --> 00:08:21,320 because NASA's Juno probe is on its way to Jupiter. 153 00:08:21,320 --> 00:08:24,360 It's spent the last couple of years wandering around the inner 154 00:08:24,360 --> 00:08:27,320 Solar System picking up speed, and at the end of last year, it 155 00:08:27,320 --> 00:08:30,680 passed by Earth for its final gravity assist. 156 00:08:30,680 --> 00:08:34,880 Remarkably, amateur astronomers were able to image it as it flew past. 157 00:08:34,880 --> 00:08:37,320 In this sequence of images from Peter Birtwhistle, 158 00:08:37,320 --> 00:08:39,680 the moving dot you can see is Juno itself 159 00:08:39,680 --> 00:08:41,400 heading off to Jupiter. 160 00:08:43,640 --> 00:08:45,800 Juno's on-board instrumentation will allow us 161 00:08:45,800 --> 00:08:48,760 to peer below the clouds for the first time. 162 00:08:48,760 --> 00:08:50,800 It will fly very close to the planet, 163 00:08:50,800 --> 00:08:53,560 a mere 5,000km above the clouds 164 00:08:53,560 --> 00:08:54,960 and below the radiation belt, 165 00:08:54,960 --> 00:08:57,640 which has stopped us from taking detailed data in the past. 166 00:08:57,640 --> 00:08:59,880 It will take detailed gravitational measurements 167 00:08:59,880 --> 00:09:02,040 and measure the atmospheric composition, 168 00:09:02,040 --> 00:09:06,120 it will also measure the mass of Jupiter's core, if there is one. 169 00:09:06,120 --> 00:09:08,640 It's an incredibly exciting mission but we'll have to wait 170 00:09:08,640 --> 00:09:11,240 until 2016 for Juno to arrive. 171 00:09:19,360 --> 00:09:22,120 Now you don't need to travel to Jupiter 172 00:09:22,120 --> 00:09:24,040 to get a fantastic image of it. 173 00:09:24,040 --> 00:09:26,080 It's possible to capture really 174 00:09:26,080 --> 00:09:28,640 detailed pictures of the planet from right here on Earth. 175 00:09:30,080 --> 00:09:32,560 And images like these, taken by amateurs, 176 00:09:32,560 --> 00:09:36,640 actually provide a unique record that even the space probes can't match. 177 00:09:38,240 --> 00:09:40,320 I've been speaking with Professor John Rogers, 178 00:09:40,320 --> 00:09:42,640 who gathers these images into a database 179 00:09:42,640 --> 00:09:44,840 that scientists can use. 180 00:09:44,840 --> 00:09:47,000 How are amateurs helping us understand Jupiter, 181 00:09:47,000 --> 00:09:48,560 where professionals can't? 182 00:09:48,560 --> 00:09:50,960 Well, amateurs are able to monitor Jupiter continuously, 183 00:09:50,960 --> 00:09:54,040 and its weather systems evolve over timescales from days, 184 00:09:54,040 --> 00:09:56,720 to months, to years, to decades, 185 00:09:56,720 --> 00:09:58,960 so we really need continuous observations 186 00:09:58,960 --> 00:10:00,680 to work out what's happening. 187 00:10:00,680 --> 00:10:03,680 They're not just doing observations, they're doing some science too? 188 00:10:03,680 --> 00:10:07,160 Yes, well, we can actually compile a record of what's going on, 189 00:10:07,160 --> 00:10:10,120 how spots like the Great Red Spot evolved, 190 00:10:10,120 --> 00:10:13,080 and we are able to monitor much smaller spots as well. 191 00:10:13,080 --> 00:10:15,840 Here for instance, you see the Great Red Spot, you can 192 00:10:15,840 --> 00:10:18,600 also see that the belts are not symmetrical. 193 00:10:18,600 --> 00:10:21,720 This dark belt is here but there's normally a dark belt up here, 194 00:10:21,720 --> 00:10:24,360 which, on this occasion in 2010, has disappeared. 195 00:10:24,360 --> 00:10:27,840 So these kind of changes are happening all the time on Jupiter, 196 00:10:27,840 --> 00:10:30,080 sometimes they take many years to unfold, 197 00:10:30,080 --> 00:10:32,480 and that's what amateurs can really study. 198 00:10:32,480 --> 00:10:35,160 I'm not used to seeing Jupiter in this orientation. 199 00:10:35,160 --> 00:10:38,120 This is the way that amateurs most commonly see it, with south up. 200 00:10:38,120 --> 00:10:40,480 So the Great Red Spot is in the southern atmosphere 201 00:10:40,480 --> 00:10:42,960 and that's how we put all our pictures up for display. 202 00:10:42,960 --> 00:10:46,120 But it's not just weather that the amateurs are spotting, 203 00:10:46,120 --> 00:10:48,320 they also find impacts. 204 00:10:48,320 --> 00:10:51,360 In 1994, the comet Shoemaker-Levy 9 205 00:10:51,360 --> 00:10:53,360 crashed into Jupiter, 206 00:10:53,360 --> 00:10:56,680 leaving dark scars in its atmosphere. 207 00:10:56,680 --> 00:10:59,400 Since then, amateurs have discovered that these 208 00:10:59,400 --> 00:11:03,160 kinds of impacts are more common than previously thought. 209 00:11:03,160 --> 00:11:06,320 In 2009, quite unexpectedly, an amateur, Anthony Wesley, 210 00:11:06,320 --> 00:11:08,880 discovered such a spot on the planet. 211 00:11:08,880 --> 00:11:11,280 This was an image he took two nights earlier, 212 00:11:11,280 --> 00:11:13,720 and then he saw this remarkably black spot 213 00:11:13,720 --> 00:11:17,240 appearing and realised that this might well be an impact. 214 00:11:17,240 --> 00:11:20,320 So other amateurs immediately started taking images to confirm 215 00:11:20,320 --> 00:11:23,240 and professional scientists took this image 216 00:11:23,240 --> 00:11:25,720 in a far-infrared wavelength. 217 00:11:25,720 --> 00:11:28,520 The Hubble Space Telescope took this image a few days lays later. 218 00:11:28,520 --> 00:11:31,000 The professional astronomers managed to follow this event 219 00:11:31,000 --> 00:11:32,200 over several months, 220 00:11:32,200 --> 00:11:35,440 while the amateurs were also tracking over several months. 221 00:11:35,440 --> 00:11:38,120 The amateurs are the watchkeepers, they keep on eye on Jupiter 222 00:11:38,120 --> 00:11:40,960 and alert the professionals when something exciting happens? 223 00:11:40,960 --> 00:11:42,680 Yes, indeed. 224 00:11:42,680 --> 00:11:46,720 More recently, amateurs have been noticing impacts while they happen. 225 00:11:46,720 --> 00:11:49,920 They are much smaller impacts, they don't leave visible scars 226 00:11:49,920 --> 00:11:54,240 but they're more frequent. And so three times since 2009, 227 00:11:54,240 --> 00:11:57,040 amateurs have actually seen fireballs in the atmosphere 228 00:11:57,040 --> 00:11:59,760 of Jupiter, which previously, if anyone had seen them, 229 00:11:59,760 --> 00:12:02,680 they didn't notice them or didn't believe they were seeing them. 230 00:12:02,680 --> 00:12:05,800 But now we have real webcam videos and it's clear that 231 00:12:05,800 --> 00:12:09,600 amateurs are actually detecting flashes as they occur. 232 00:12:09,600 --> 00:12:12,240 So how does an amateur get involved? 233 00:12:12,240 --> 00:12:15,280 The best way for someone who hasn't done it before is to 234 00:12:15,280 --> 00:12:17,280 contact their local astronomical society. 235 00:12:17,280 --> 00:12:19,560 There they'll meet people who are themselves 236 00:12:19,560 --> 00:12:21,880 getting into the same kind of observations, 237 00:12:21,880 --> 00:12:24,200 finding out how to use the same kind of equipment, 238 00:12:24,200 --> 00:12:26,320 and I think that it's the personal contacts 239 00:12:26,320 --> 00:12:28,080 that are most useful to someone 240 00:12:28,080 --> 00:12:31,000 who hasn't experienced this kind of technology before. 241 00:12:31,000 --> 00:12:33,080 Thanks, John, that was pretty fascinating 242 00:12:33,080 --> 00:12:36,440 and it shows the power of amateur astronomy. Thank you. 243 00:12:43,520 --> 00:12:46,600 Now Pete Lawrence is here with his guide to what else you can 244 00:12:46,600 --> 00:12:49,640 see in the night sky around Jupiter. 245 00:12:49,640 --> 00:12:52,800 But first, he's got a simple tip that can help address 246 00:12:52,800 --> 00:12:56,560 one of the main problems that people face when they're stargazing - 247 00:12:56,560 --> 00:12:59,760 how to match a star chart to the real night sky. 248 00:12:59,760 --> 00:13:04,480 And he's with the Hampshire Astronomical Group on the South Downs. 249 00:13:04,480 --> 00:13:06,640 Jupiter is pretty easy to find at the moment 250 00:13:06,640 --> 00:13:10,120 because it's the brightest thing visible in the early evening 251 00:13:10,120 --> 00:13:13,520 part of the night sky, apart from when the moon's about, of course. 252 00:13:13,520 --> 00:13:15,960 For many people, when they look up at the night sky, 253 00:13:15,960 --> 00:13:19,640 it can be a bit of a challenge to work out what is what. 254 00:13:19,640 --> 00:13:22,760 But there are a few simple tips you can follow which will 255 00:13:22,760 --> 00:13:24,160 make your life easier. 256 00:13:24,160 --> 00:13:27,680 One of most difficult things for those starting out 257 00:13:27,680 --> 00:13:29,000 is judging scale. 258 00:13:29,000 --> 00:13:32,880 How do you relate the distance between stars on a star chart 259 00:13:32,880 --> 00:13:35,520 to the distance in the night sky? 260 00:13:35,520 --> 00:13:37,080 It might sound surprising, 261 00:13:37,080 --> 00:13:39,720 but the best thing to do is to use your hands. 262 00:13:41,760 --> 00:13:43,440 If you hold it out at arm's length, 263 00:13:43,440 --> 00:13:46,640 like that, the distance between your thumb 264 00:13:46,640 --> 00:13:48,520 and little finger is the same. 265 00:13:48,520 --> 00:13:50,840 If you've got big hands or little hands, 266 00:13:50,840 --> 00:13:53,280 the length of your arm tends to compensate for it. 267 00:13:53,280 --> 00:13:55,000 So if you look at Orion - you can 268 00:13:55,000 --> 00:13:57,000 see the bright star in the upper left corner 269 00:13:57,000 --> 00:13:59,840 and the bright star in the lower right corner - you can 270 00:13:59,840 --> 00:14:03,120 see that it fits more or less between those two. 271 00:14:03,120 --> 00:14:04,520 For all of us, even though 272 00:14:04,520 --> 00:14:07,360 we've got different sized hands and different length of arms, 273 00:14:07,360 --> 00:14:11,680 you can actually hold two fingers up as well, that's a good indicator. 274 00:14:11,680 --> 00:14:15,120 Just starting to appreciate the scale of patterns in the night sky 275 00:14:15,120 --> 00:14:17,480 and you can relate that back to a star chart 276 00:14:17,480 --> 00:14:20,280 and then gradually work your way across the sky. 277 00:14:20,280 --> 00:14:24,680 Once you understand the apparent distances between stars, 278 00:14:24,680 --> 00:14:27,320 finding anything in the sky should be much easier. 279 00:14:28,760 --> 00:14:31,440 Jupiter is obviously the highlight up there at the moment, 280 00:14:31,440 --> 00:14:32,880 it's magnificent. 281 00:14:32,880 --> 00:14:36,440 But there's a lot more to be seen around that area and I've picked out 282 00:14:36,440 --> 00:14:40,280 some of my favourite highlights for this month's star guide. 283 00:14:42,360 --> 00:14:45,960 The magnificent constellation of Orion lies south in the early 284 00:14:45,960 --> 00:14:48,160 evening during February. 285 00:14:48,160 --> 00:14:50,760 Its seven bright stars are easy to pick out 286 00:14:50,760 --> 00:14:54,160 and create a great signpost in the night sky. 287 00:14:54,160 --> 00:14:57,440 Look out in particular for Orion's Sword that appears to hang 288 00:14:57,440 --> 00:15:02,040 down from the belt, a region which contains the fabulous Orion Nebula. 289 00:15:03,240 --> 00:15:04,680 Follow the line made by 290 00:15:04,680 --> 00:15:06,520 Orion's Belt down the left 291 00:15:06,520 --> 00:15:08,080 to locate Sirius - 292 00:15:08,080 --> 00:15:10,560 the brightest night-time star. 293 00:15:10,560 --> 00:15:11,800 About one-and-a-half 294 00:15:11,800 --> 00:15:13,520 outstretched hand widths 295 00:15:13,520 --> 00:15:16,000 above and left of Sirius is another 296 00:15:16,000 --> 00:15:18,480 bright star called Procyon. 297 00:15:21,320 --> 00:15:23,360 Join the dots of Sirius, Procyon 298 00:15:23,360 --> 00:15:25,400 and orange Betelgeuse to form 299 00:15:25,400 --> 00:15:26,560 a pattern known as 300 00:15:26,560 --> 00:15:28,040 the Winter Triangle. 301 00:15:28,040 --> 00:15:29,320 The winter Milky Way 302 00:15:29,320 --> 00:15:31,240 passes through this region. 303 00:15:31,240 --> 00:15:32,320 Scanning the area 304 00:15:32,320 --> 00:15:33,600 with a pair of binoculars 305 00:15:33,600 --> 00:15:34,760 reveals many faint 306 00:15:34,760 --> 00:15:36,680 and beautiful star clusters. 307 00:15:42,040 --> 00:15:45,040 Extend a line from Rigel, in Orion, 308 00:15:45,040 --> 00:15:48,120 through Betelgeuse for twice the distance again - 309 00:15:48,120 --> 00:15:50,400 that's two outstretched hand widths - 310 00:15:50,400 --> 00:15:52,120 to arrive at a pair of stars 311 00:15:52,120 --> 00:15:55,800 in Gemini known as Castor and Pollux. 312 00:15:55,800 --> 00:15:58,680 They are about three finger widths apart. 313 00:16:01,960 --> 00:16:06,120 If you traced the pattern of the famous twins back towards Orion, 314 00:16:06,120 --> 00:16:10,360 you'll find the unmistakably bright planet Jupiter. 315 00:16:12,960 --> 00:16:16,000 Jupiter is currently visible more or less all night long. 316 00:16:16,000 --> 00:16:19,600 If you go out and catch it early, it's possible to see 317 00:16:19,600 --> 00:16:23,080 a full rotation of the planet, that's one whole day on Jupiter. 318 00:16:23,080 --> 00:16:25,720 If you get some lovely pictures of that, send them in to us 319 00:16:25,720 --> 00:16:27,680 and we'll put the best ones up on our website. 320 00:16:29,040 --> 00:16:31,000 Speaking of your photos, we've got 321 00:16:31,000 --> 00:16:34,040 some great ones that have been uploaded to our website. 322 00:16:34,040 --> 00:16:36,920 And here are a few that really stand out. 323 00:16:39,200 --> 00:16:43,360 This is the Orion Nebula, which lies on Orion's Sword, 324 00:16:43,360 --> 00:16:45,040 taken by Steve Richards. 325 00:16:47,480 --> 00:16:49,920 Luke Stacy captured this image 326 00:16:49,920 --> 00:16:52,840 of a chain of sun spots on 2nd February. 327 00:16:58,240 --> 00:17:01,760 This shot by Mary Spicer shows how light bouncing off 328 00:17:01,760 --> 00:17:05,760 the Earth can illuminate the parts of the moon that lie in shadow. 329 00:17:06,800 --> 00:17:08,280 And this is Centaurus A, 330 00:17:08,280 --> 00:17:12,280 a galaxy that lies too far south to be viewed directly from Britain. 331 00:17:12,280 --> 00:17:17,560 It was taken over an astonishing 43 nights by Rolf Olson. 332 00:17:17,560 --> 00:17:20,560 To send us your images, go to our website at... 333 00:17:23,800 --> 00:17:25,560 Since we were last on air, 334 00:17:25,560 --> 00:17:28,160 there has been plenty happening in the astronomical world 335 00:17:28,160 --> 00:17:31,160 and the most spectacular event has been a new supernova. Yes. 336 00:17:31,160 --> 00:17:35,600 A supernova is the dying throes of larger stars. 337 00:17:35,600 --> 00:17:38,840 And we have one here captured by some UCL students. 338 00:17:38,840 --> 00:17:41,320 So this is the M82 cigar galaxy. 339 00:17:41,320 --> 00:17:45,320 And here, on 21st January, we have a new bright object - the supernova. 340 00:17:45,320 --> 00:17:48,720 And what I love about this is this discovery was made by Steve Fossey 341 00:17:48,720 --> 00:17:50,640 and a bunch of students just up the road 342 00:17:50,640 --> 00:17:53,600 at the UCL's Mill Hill observatory. 343 00:17:53,600 --> 00:17:56,320 But even better, it was a ten-minute gap where it wasn't cloudy. 344 00:17:56,320 --> 00:18:00,400 Exactly. A discovery from within the M25. And it's perfect. 345 00:18:00,400 --> 00:18:04,560 It's a type 1a supernova, which are quite rare. That's right. 346 00:18:04,560 --> 00:18:07,560 We use these to measure how the universe is expanding. 347 00:18:07,560 --> 00:18:10,280 So they're bright, so you can see them from a long distance away, 348 00:18:10,280 --> 00:18:12,160 and that means we can use them 349 00:18:12,160 --> 00:18:15,000 to work out how the universe is accelerating. 350 00:18:15,000 --> 00:18:17,160 But, embarrassingly, we don't know what they are. 351 00:18:17,160 --> 00:18:20,040 We've ideas that they might be a massive star spiralling 352 00:18:20,040 --> 00:18:23,160 material down onto a white dwarf, which then explodes, but we're 353 00:18:23,160 --> 00:18:25,920 not sure and that's why we need these local ones to try and help us. 354 00:18:25,920 --> 00:18:27,560 This is 12 million light years away 355 00:18:27,560 --> 00:18:29,600 which is pretty local. Just round the corner. 356 00:18:29,600 --> 00:18:32,800 Yes! Is still visible now or does it decay very rapidly? 357 00:18:32,800 --> 00:18:34,760 It will be visible for the next few months. 358 00:18:34,760 --> 00:18:38,200 It was caught early enough that it was still brightening 359 00:18:38,200 --> 00:18:40,520 so it will be at its brightest about now. 360 00:18:40,520 --> 00:18:41,760 So go out, find M82. 361 00:18:41,760 --> 00:18:45,040 If you look in binoculars, you should see it easily. 362 00:18:45,040 --> 00:18:47,120 It won't quite make it to naked eye visibility 363 00:18:47,120 --> 00:18:48,600 unless something odd happens 364 00:18:48,600 --> 00:18:50,520 but it'll be an easy target for binoculars. 365 00:18:50,520 --> 00:18:51,760 The brightest supernova 366 00:18:51,760 --> 00:18:53,880 we've had in the northern hemisphere for years. 367 00:18:53,880 --> 00:18:56,920 Speaking of celestial spectaculars, we had hoped before 368 00:18:56,920 --> 00:19:00,320 Christmas that comet ISON was going to put on a great show for us 369 00:19:00,320 --> 00:19:02,600 but it didn't quite work out like that 370 00:19:02,600 --> 00:19:05,280 and Alan Fitzsimmons is going to tell us why. 371 00:19:07,080 --> 00:19:11,560 People were predicting that ISON would be the comet of the century 372 00:19:11,560 --> 00:19:13,320 that, as it came round the sun, 373 00:19:13,320 --> 00:19:16,520 a huge tail would be created that would fill the night sky. 374 00:19:17,560 --> 00:19:22,040 However, instead, it seems to have fizzled out. 375 00:19:22,040 --> 00:19:26,320 But now, by pulling data from a number of scientific instruments, 376 00:19:26,320 --> 00:19:29,800 it's possible to find out what actually happened. 377 00:19:29,800 --> 00:19:31,200 Here we've got the comet 378 00:19:31,200 --> 00:19:34,920 about a couple of hours before closest approach to the sun. 379 00:19:34,920 --> 00:19:37,560 We can already see that something has happened to the comet. 380 00:19:37,560 --> 00:19:39,800 In a normal comet, we expect to see 381 00:19:39,800 --> 00:19:42,200 a very bright, distinct head, or coma, 382 00:19:42,200 --> 00:19:43,760 form from all the gas 383 00:19:43,760 --> 00:19:47,360 and small dust particles that the comet has released. 384 00:19:47,360 --> 00:19:51,200 Here we can see the tail of the comet 385 00:19:51,200 --> 00:19:52,960 but the head itself is already 386 00:19:52,960 --> 00:19:56,200 not looking like a normal comet does - 387 00:19:56,200 --> 00:19:57,640 it's spread out. 388 00:19:57,640 --> 00:19:59,480 And even by this point, 389 00:19:59,480 --> 00:20:01,200 a couple of hours before it reached 390 00:20:01,200 --> 00:20:02,560 its closest point to the sun, 391 00:20:02,560 --> 00:20:04,200 the comet nucleus itself 392 00:20:04,200 --> 00:20:06,520 had been dispersed. Interestingly, 393 00:20:06,520 --> 00:20:09,560 it's still far enough from the sun that it shouldn't have been 394 00:20:09,560 --> 00:20:11,600 broken up by the gravitational field, 395 00:20:11,600 --> 00:20:15,040 the tidal forces imparted on the nucleus by the sun, 396 00:20:15,040 --> 00:20:18,720 but what's happened is simply its nucleus has been heated 397 00:20:18,720 --> 00:20:23,200 so much and is releasing so much gas and material from its surface, 398 00:20:23,200 --> 00:20:26,600 that pressure of that material building up in the comet 399 00:20:26,600 --> 00:20:28,960 has simply broken it apart. 400 00:20:30,560 --> 00:20:33,880 And so ISON was doomed long before it reached the sun. 401 00:20:33,880 --> 00:20:35,960 And as it passed around our star, 402 00:20:35,960 --> 00:20:39,440 it reappeared as nothing more than a cloud of debris. 403 00:20:40,840 --> 00:20:42,520 But there is still a question about 404 00:20:42,520 --> 00:20:46,560 whether anything of the nucleus had survived to live another day. 405 00:20:47,720 --> 00:20:52,440 On December 16th, the Hubble Space Telescope went to have 406 00:20:52,440 --> 00:20:54,880 a look at where the comet was predicted to be. 407 00:20:54,880 --> 00:20:59,280 Now it's tracking where we expect the comet to be moving, 408 00:20:59,280 --> 00:21:03,600 so all the background stars and galaxies appear as streaks. 409 00:21:03,600 --> 00:21:06,960 But if there was any comet left, we would see it as a point-like 410 00:21:06,960 --> 00:21:09,120 source here and we don't see anything. 411 00:21:09,120 --> 00:21:11,520 So these Hubble Telescope images here 412 00:21:11,520 --> 00:21:16,680 imply that there really isn't anything left at all of the nucleus. 413 00:21:16,680 --> 00:21:19,480 So it's a shame. ISON is gone - 414 00:21:19,480 --> 00:21:22,760 but it gave us a great show on its way in. 415 00:21:26,160 --> 00:21:29,400 And we've got one more item of news this month. 416 00:21:29,400 --> 00:21:31,960 In January, as part of Stargazing LIVE, 417 00:21:31,960 --> 00:21:35,520 I challenged people to go online and look at pictures of galaxies 418 00:21:35,520 --> 00:21:37,440 and look for gravitational lenses - 419 00:21:37,440 --> 00:21:40,680 places where a distant galaxy has had its light bent 420 00:21:40,680 --> 00:21:43,920 by a gravitational lens, by passing near a nearby galaxy. 421 00:21:43,920 --> 00:21:46,280 We found lots of spectacular things 422 00:21:46,280 --> 00:21:48,560 but the one we talked about on the night was this one. 423 00:21:48,560 --> 00:21:52,560 This is an infrared image of that galaxy. Yes. What have we got? 424 00:21:52,560 --> 00:21:55,200 In the centre, that's the galaxy? That's the nearby galaxy. 425 00:21:55,200 --> 00:21:57,760 And the red arc that you can see, almost the red ring there, 426 00:21:57,760 --> 00:22:00,920 is a distant galaxy whose light has been bent 427 00:22:00,920 --> 00:22:03,960 and we're seeing it because it's being lensed by this nearby galaxy. 428 00:22:03,960 --> 00:22:06,480 Without that galaxy, we wouldn't have a chance of seeing it? 429 00:22:06,480 --> 00:22:08,080 Exactly. It's nature's telescope. 430 00:22:08,080 --> 00:22:10,640 This is the infrared. What we've been doing since 431 00:22:10,640 --> 00:22:12,960 is we've looked at it in the radio using Jodrell. 432 00:22:12,960 --> 00:22:15,920 This is the image that we've got. It does look like different. 433 00:22:15,920 --> 00:22:17,040 It does. 434 00:22:17,040 --> 00:22:20,160 For starters, it's blobby because it's a radio image 435 00:22:20,160 --> 00:22:22,880 and you don't get the beautiful pictures you do in the infrared. 436 00:22:22,880 --> 00:22:25,480 The other thing, I don't know if I can convince you of this, 437 00:22:25,480 --> 00:22:27,320 but in the infrared we saw that red ring, 438 00:22:27,320 --> 00:22:28,720 in the radio, it's only one arc. 439 00:22:28,720 --> 00:22:31,760 It definitely looks one-sided. 440 00:22:31,760 --> 00:22:35,080 So where's the rest of it gone? Exactly. It's quite confusing. 441 00:22:35,080 --> 00:22:37,360 Our best guess at the minute is that the radio 442 00:22:37,360 --> 00:22:40,360 and the infrared radiation come from different parts of the galaxy. 443 00:22:40,360 --> 00:22:43,120 So the infrared comes from star formation spread out through 444 00:22:43,120 --> 00:22:46,000 the whole galaxy - and the galaxy's forming stars at a great rate, 445 00:22:46,000 --> 00:22:48,080 about 100 times that of the Milky Way. 446 00:22:48,080 --> 00:22:50,680 And the radio, we think, comes from right in the centre, 447 00:22:50,680 --> 00:22:53,600 from the nucleus where material is spiralling onto 448 00:22:53,600 --> 00:22:56,560 what must be a growing black hole in the centre of this galaxy. 449 00:22:56,560 --> 00:22:58,400 This is what I love. Looking at the sky 450 00:22:58,400 --> 00:23:00,600 in different bands of the electromagnetic spectrum 451 00:23:00,600 --> 00:23:03,520 gives you a very different viewpoint and different understandings. 452 00:23:03,520 --> 00:23:05,600 That's right. We knew that was true. 453 00:23:05,600 --> 00:23:07,760 It's only the second time that we've seen this 454 00:23:07,760 --> 00:23:10,760 misalignment between a radio lens and an infrared lens. 455 00:23:10,760 --> 00:23:13,840 A perfect ring in the infrared and nice to blobby arc in the radio. 456 00:23:13,840 --> 00:23:15,320 It's quite fun. 457 00:23:15,320 --> 00:23:17,120 If you go to the Sky At Night website, 458 00:23:17,120 --> 00:23:20,120 we've actually put some more data online. If you follow the link, 459 00:23:20,120 --> 00:23:22,560 you might be able to discover your own lensed galaxy. 460 00:23:28,400 --> 00:23:30,760 Well, back to Jupiter, and we're in the Endeavour Room 461 00:23:30,760 --> 00:23:32,520 of the Royal Observatory Greenwich, 462 00:23:32,520 --> 00:23:35,240 which these days is a library but which used to house 463 00:23:35,240 --> 00:23:37,440 some of the largest telescopes on the site. 464 00:23:37,440 --> 00:23:40,520 It was in this room, in 1908, that British astronomer 465 00:23:40,520 --> 00:23:43,360 Melotte discovered a moon of Jupiter. 466 00:23:43,360 --> 00:23:48,440 This is the image and this dot here is the moon we now call Pasiphae. 467 00:23:48,440 --> 00:23:51,400 Exciting things are happening with the moons of Jupiter 468 00:23:51,400 --> 00:23:53,840 and to discuss them I'm joined by Dr Leigh Fletcher, 469 00:23:53,840 --> 00:23:55,480 an expert on the Jupiter system. 470 00:23:55,480 --> 00:23:57,560 Leigh, welcome to the programme. Thank you. 471 00:23:57,560 --> 00:23:59,360 We're going to talk about Europa, 472 00:23:59,360 --> 00:24:02,680 where jets of water have been discovered shooting into space. 473 00:24:02,680 --> 00:24:04,840 We knew there was water on Europa already. 474 00:24:04,840 --> 00:24:08,040 We did. Europa has always been a tantalising place for us 475 00:24:08,040 --> 00:24:11,440 to one day go and explore and now more so with this new result of 476 00:24:11,440 --> 00:24:15,160 plumes of water vapour being emitted from the south pole of Europa. 477 00:24:15,160 --> 00:24:18,680 It's going to be a fabulous thing for us to go and look at one day. 478 00:24:18,680 --> 00:24:21,680 Europa's an icy moon and that's what we see when we look at the surface. 479 00:24:21,680 --> 00:24:25,720 Europa is the second of four Galilean satellites in orbit 480 00:24:25,720 --> 00:24:28,480 around the Jupiter. It's about the size of our own moon. 481 00:24:28,480 --> 00:24:30,400 If you look at it here on the screen, you can see. 482 00:24:30,400 --> 00:24:32,600 It's an icy ball, Europa is, 483 00:24:32,600 --> 00:24:35,880 and the different colours that you see across the surface 484 00:24:35,880 --> 00:24:38,520 are contaminants in the ice itself. 485 00:24:38,520 --> 00:24:42,040 It almost looks like you've got a frozen ice raft, 486 00:24:42,040 --> 00:24:46,080 frozen then into a body of liquid water that has re-frozen. 487 00:24:46,080 --> 00:24:47,760 We call it chaos terrain. 488 00:24:47,760 --> 00:24:50,840 We can zoom in to get a proper look. Yeah. There we go. 489 00:24:50,840 --> 00:24:53,560 This is one of the key pieces of evidence which suggests 490 00:24:53,560 --> 00:24:57,040 that beneath this terrain there is liquid water. 491 00:24:57,040 --> 00:25:02,080 Liquid water in our solar system locked away beneath the icy service. 492 00:25:02,080 --> 00:25:05,000 We've been talking about this for years. There's an annoying catch, 493 00:25:05,000 --> 00:25:06,840 isn't there, that the ice is pretty thick? 494 00:25:06,840 --> 00:25:10,400 This is the typical thing within our solar system of the ability 495 00:25:10,400 --> 00:25:13,800 to sense what we really want to see, which is that ocean, 496 00:25:13,800 --> 00:25:16,280 is forbidden to us because it's hidden away, 497 00:25:16,280 --> 00:25:18,000 locked away, or so we thought. 498 00:25:18,000 --> 00:25:21,240 But now, with the discovery of these water vapour plumes, 499 00:25:21,240 --> 00:25:24,480 we have a tantalising chance to fly through those plumes 500 00:25:24,480 --> 00:25:27,680 and sniff out the composition. Let's look at that that new observation. 501 00:25:27,680 --> 00:25:29,600 This was released at the end of last year. 502 00:25:29,600 --> 00:25:31,760 It's a Hubble Space Telescope observation. 503 00:25:31,760 --> 00:25:33,720 And I have to say, Leigh, looking at this, 504 00:25:33,720 --> 00:25:36,000 it's not hugely convincing. 505 00:25:36,000 --> 00:25:38,760 I'm very sorry that you're disappointed but this is actually 506 00:25:38,760 --> 00:25:40,880 a really exciting discovery that the folks with 507 00:25:40,880 --> 00:25:43,320 the Hubble Space Telescope made just that while ago. 508 00:25:43,320 --> 00:25:46,800 Don't forget that you're seeing this from planet Earth, 509 00:25:46,800 --> 00:25:48,360 five astronomical units away. 510 00:25:48,360 --> 00:25:50,720 Five times as far away from the sun as the Earth is. 511 00:25:50,720 --> 00:25:53,760 Absolutely. All the way out at the orbit of Jupiter. 512 00:25:53,760 --> 00:25:57,120 This is an artist's impression superimposing the two together. 513 00:25:57,120 --> 00:25:58,880 What they're looking at here is 514 00:25:58,880 --> 00:26:01,520 ultraviolet emission from hydrogen and oxygen. 515 00:26:01,520 --> 00:26:04,080 So this is water that has been spewed out of the moon 516 00:26:04,080 --> 00:26:08,240 and has then been disassociated, split apart... By the sun's light. 517 00:26:08,240 --> 00:26:10,080 Exactly, by UV radiation. 518 00:26:10,080 --> 00:26:12,960 We can see that emanating from the south pole. 519 00:26:12,960 --> 00:26:16,400 We're talking about a plume of water 200km high 520 00:26:16,400 --> 00:26:18,200 over the south pole of Europa. 521 00:26:18,200 --> 00:26:21,040 I can tell you we didn't expect to see that. 522 00:26:21,040 --> 00:26:22,800 How have we got water at the south pole? 523 00:26:22,800 --> 00:26:26,200 What's going on here is we've got these cracks, and these fissures 524 00:26:26,200 --> 00:26:30,080 and stripes, which are undergoing different amounts of stress 525 00:26:30,080 --> 00:26:32,080 as the moon goes round Jupiter. 526 00:26:32,080 --> 00:26:35,560 The orbit of Europa around Jupiter is not perfectly circular 527 00:26:35,560 --> 00:26:37,680 and that means sometimes it's closer to Jupiter, 528 00:26:37,680 --> 00:26:39,040 where the gravity's stronger, 529 00:26:39,040 --> 00:26:41,720 and sometimes it's further away, where the gravity is weaker. 530 00:26:41,720 --> 00:26:44,600 Jupiter's a big thing, its pull is pretty significant. 531 00:26:44,600 --> 00:26:46,680 It's an immense gravitational field, 532 00:26:46,680 --> 00:26:49,520 that means, when Europa is far away from the moon... 533 00:26:49,520 --> 00:26:50,760 Like this observation. 534 00:26:50,760 --> 00:26:54,440 Like this observation in December 2012, things are relaxed, 535 00:26:54,440 --> 00:26:57,280 you're able to emanate these plumes out of the south pole. 536 00:26:57,280 --> 00:27:00,920 Now the team also have observations from just a month earlier. 537 00:27:00,920 --> 00:27:03,680 At that point, Europa was much closer in to Jupiter, 538 00:27:03,680 --> 00:27:06,400 so where the gravity field is stronger, 539 00:27:06,400 --> 00:27:09,040 if you like, no plumes were observed at that point. 540 00:27:09,040 --> 00:27:12,040 So you have this situation, extremely dynamically rich, 541 00:27:12,040 --> 00:27:15,560 where the plumes are only emanating their material into space 542 00:27:15,560 --> 00:27:18,080 when the stress is at its lowest point - 543 00:27:18,080 --> 00:27:21,000 at the furthest distance away from Jupiter. 544 00:27:21,000 --> 00:27:23,360 Now this is a fabulously exciting discovery. 545 00:27:23,360 --> 00:27:24,880 It provides access to this water - 546 00:27:24,880 --> 00:27:27,360 the stuff we thought was locked up under the surface - 547 00:27:27,360 --> 00:27:29,560 and you have a mission, or you're part of a team 548 00:27:29,560 --> 00:27:32,440 working on a mission, called JUICE, which is heading to Europa. 549 00:27:32,440 --> 00:27:34,360 How does this change your plans? 550 00:27:34,360 --> 00:27:38,480 It's being built by the European Space Agency to launch in 2022, 551 00:27:38,480 --> 00:27:40,760 or thereabouts and, at the moment, 552 00:27:40,760 --> 00:27:44,600 we are scheduled to have two flybys of Europa in 2031. 553 00:27:44,600 --> 00:27:47,480 We are going to be up close and personal with those plumes, able to 554 00:27:47,480 --> 00:27:50,800 look at the light as it is being filtered and scattered through them. 555 00:27:50,800 --> 00:27:54,080 We've even got instruments on-board capable of detecting 556 00:27:54,080 --> 00:27:56,120 the sorts of materials that are emanating. 557 00:27:56,120 --> 00:27:58,200 There's a huge caveat to that, I should say. 558 00:27:58,200 --> 00:28:00,960 What if this material isn't coming from the ocean? 559 00:28:00,960 --> 00:28:03,680 Maybe it's the action of something heating up 560 00:28:03,680 --> 00:28:05,400 in just the very top layers. 561 00:28:05,400 --> 00:28:07,440 Even then, it's still exciting because it's a way 562 00:28:07,440 --> 00:28:09,200 we can sample the surface materials 563 00:28:09,200 --> 00:28:11,560 from our spacecraft without landing on the surface. 564 00:28:11,560 --> 00:28:13,400 So when does JUICE get there? 565 00:28:13,400 --> 00:28:17,800 JUICE will get there in 2030 and it will fly by Europa twice in 2031. 566 00:28:17,800 --> 00:28:20,960 Fabulous. Come back and tell us about it and good luck. Thank you. 567 00:28:20,960 --> 00:28:23,080 Leigh, thanks a lot. Thank you. 568 00:28:29,040 --> 00:28:31,880 So that's it for this month, but do remember to keep on sending 569 00:28:31,880 --> 00:28:34,200 your pictures in, especially if you manage to get 570 00:28:34,200 --> 00:28:37,240 a full rotation of Jupiter, and we'll put the best on our website. 571 00:28:37,240 --> 00:28:40,080 When we come back next month, will be listening to the cosmos - 572 00:28:40,080 --> 00:28:42,880 studying sound waves to find out what they can tell us 573 00:28:42,880 --> 00:28:45,280 about the Universe's hidden secrets. 574 00:28:45,280 --> 00:28:47,040 And we'll also be looking at how to get 575 00:28:47,040 --> 00:28:49,800 wonderful images of the night sky with just a smartphone. 576 00:28:49,800 --> 00:28:54,200 So remember, get outside and get looking up. Good night. 577 00:28:54,200 --> 00:28:58,880 THEME MUSIC: "At The Castle Gate" from "Pelleas and Melisande Suite" by Jean Sibelius