WEBVTT 0 00:00:00.320 --> 00:00:02.560 Andrew Dunkley: Hello there. Thanks for joining us. This is 1 00:00:02.560 --> 00:00:05.360 Space Nuts, where we talk astronomy and 2 00:00:05.360 --> 00:00:07.920 space science. My name is Andrew Dunkley. 3 00:00:07.920 --> 00:00:10.480 Great to have your company on this, the 4 00:00:10.480 --> 00:00:13.200 600 millionth episode. Maybe not that many, 5 00:00:13.200 --> 00:00:15.040 but we've done quite a few. What is it, 6 00:00:15.280 --> 00:00:17.840 643 we're up to? Blimey. 7 00:00:18.320 --> 00:00:19.920 All right, uh, what are we talking about? 8 00:00:19.920 --> 00:00:22.880 We're talking about, um, an old clapped out, 9 00:00:23.000 --> 00:00:25.280 uh, telescope. Fred Watson happens to be its 10 00:00:25.280 --> 00:00:27.460 patron. He's old and clapped out too. Uh, 11 00:00:27.460 --> 00:00:30.080 we're also going to look, uh, at 12 00:00:30.480 --> 00:00:32.860 a new black hole discovery which was made 13 00:00:33.020 --> 00:00:35.660 after, um, two black holes 14 00:00:35.660 --> 00:00:38.340 collided and they recorded the loudest crash 15 00:00:38.340 --> 00:00:41.260 of gravitational waves ever. So 16 00:00:41.260 --> 00:00:43.820 what's it going to tell us? Also, uh, China 17 00:00:43.820 --> 00:00:45.980 is going to upgrade its space station and 18 00:00:45.980 --> 00:00:48.820 launch a new space telescope. And a 19 00:00:48.820 --> 00:00:51.740 star that got close to our sun 20 00:00:51.740 --> 00:00:53.900 may have caused a bit of a disturbance in the 21 00:00:53.900 --> 00:00:56.300 force. We'll tell you all about it on this 22 00:00:56.300 --> 00:00:58.300 episode of space nuts. 23 00:00:58.380 --> 00:01:00.860 Professor Fred Watson: 15 seconds. Guidance is internal. 24 00:01:01.100 --> 00:01:03.740 10, 9. Ignition 25 00:01:04.040 --> 00:01:04.480 sequence. 26 00:01:04.480 --> 00:01:04.560 Andrew Dunkley: Star. 27 00:01:04.560 --> 00:01:07.546 Professor Fred Watson: Uh, space nuts. 5, 4, 3, 2. 1. 28 00:01:07.617 --> 00:01:10.371 2, 3, 4, 5, 5, 4, 3, 2, 29 00:01:10.442 --> 00:01:10.760 1. 30 00:01:10.840 --> 00:01:13.600 Andrew Dunkley: Space nuts. Astronauts report it feels 31 00:01:13.600 --> 00:01:16.600 good. And he's back again. As always, 32 00:01:16.920 --> 00:01:19.360 it's Professor Fred Watson Watson, astronomer 33 00:01:19.360 --> 00:01:20.360 at large. Hello, Fred Watson. 34 00:01:20.360 --> 00:01:22.800 Professor Fred Watson: Hello, Andrew. Hello. Uh, thank you for that 35 00:01:22.800 --> 00:01:25.150 nice introduction. It's, uh, 36 00:01:25.480 --> 00:01:28.440 nice to hear welcome like that. 37 00:01:29.240 --> 00:01:31.800 Andrew Dunkley: You know, I know I only said it a few seconds 38 00:01:31.800 --> 00:01:33.720 ago, but I forgot what I said. And then it 39 00:01:33.720 --> 00:01:35.560 dawned on me that I'd actually insulted. 40 00:01:35.780 --> 00:01:37.780 Professor Fred Watson: Yes. Oh, forget about that. Yeah, no, that's 41 00:01:37.780 --> 00:01:39.620 all right, that's all right. You're right. 42 00:01:39.860 --> 00:01:40.500 Andrew Dunkley: Last week. 43 00:01:40.500 --> 00:01:42.660 Professor Fred Watson: I am old and clapped out. There's no question 44 00:01:42.740 --> 00:01:43.460 about that. 45 00:01:44.020 --> 00:01:46.580 Andrew Dunkley: Aren't we all, Aren't we all? 46 00:01:47.260 --> 00:01:50.040 Um, now, um, before we get into, uh, 47 00:01:50.040 --> 00:01:52.380 today's storeys, um, the old clapped out 48 00:01:52.380 --> 00:01:54.840 telescope I referred to is actually a, uh, 49 00:01:54.940 --> 00:01:57.620 wonderful device, uh, that I've actually seen 50 00:01:57.780 --> 00:02:00.540 in person when we were down in Melbourne a 51 00:02:00.540 --> 00:02:03.230 few years ago. Uh, it's the 52 00:02:03.230 --> 00:02:05.350 Melbourne telescope. Dates back to 53 00:02:05.350 --> 00:02:08.310 1869. And you're its patron because you 54 00:02:08.310 --> 00:02:10.230 were there when they put the first screw in 55 00:02:10.230 --> 00:02:11.830 it. Got you again. 56 00:02:12.870 --> 00:02:15.670 Professor Fred Watson: Yeah. So the link and the reason why I'm. 57 00:02:15.670 --> 00:02:17.470 Well, there's a number of reasons why this 58 00:02:17.470 --> 00:02:19.590 telescope is very close to my heart. One is 59 00:02:19.590 --> 00:02:22.470 that, uh, I was 60 00:02:22.470 --> 00:02:24.830 still at school when I found a picture of it 61 00:02:24.830 --> 00:02:27.550 in Henry King's History of the Telescope, a 62 00:02:27.550 --> 00:02:30.430 very famous book, uh, on the history of 63 00:02:30.430 --> 00:02:33.030 telescopes, published, I think in 1955. 64 00:02:33.830 --> 00:02:35.730 Had a copy of that in the school library. And 65 00:02:35.730 --> 00:02:37.130 there's this telescope there, the Great 66 00:02:37.130 --> 00:02:39.490 Melbourne Telescope. And I thought that is. 67 00:02:39.650 --> 00:02:42.250 That is a telescope. That's what I want one 68 00:02:42.250 --> 00:02:43.130 like looks. 69 00:02:43.130 --> 00:02:46.010 Andrew Dunkley: It just looks like you'd expect one to 70 00:02:46.010 --> 00:02:46.690 look, doesn't it? 71 00:02:46.690 --> 00:02:48.930 Professor Fred Watson: You can tell it's a telescope. It's got um. 72 00:02:48.930 --> 00:02:51.650 With decorative bits like the latticework 73 00:02:51.730 --> 00:02:54.170 tube, which is uh, very unusual, almost 74 00:02:54.170 --> 00:02:57.010 unique. Anyway, that was my first 75 00:02:57.380 --> 00:03:00.210 um, encounter with it. Uh, and as 76 00:03:00.210 --> 00:03:01.970 sort of followed up as much as I could. A 77 00:03:02.150 --> 00:03:04.070 didn't realise that by then it was actually 78 00:03:04.280 --> 00:03:07.110 uh, in Canberra at Matt Stromlo. It had been 79 00:03:07.110 --> 00:03:10.070 refurbished, um, having left Melbourne in 80 00:03:10.070 --> 00:03:12.820 1944. But, uh, 81 00:03:12.870 --> 00:03:15.030 100 years 82 00:03:15.510 --> 00:03:18.430 exactly after work started on 83 00:03:18.430 --> 00:03:21.150 the manufacture of that telescope in 84 00:03:21.150 --> 00:03:24.030 1867, 100 years later I 85 00:03:24.030 --> 00:03:25.750 joined the company that built it. 86 00:03:27.510 --> 00:03:30.270 So it was uh, its 20th 87 00:03:30.270 --> 00:03:33.030 century equivalent. It was uh, Howard 88 00:03:33.030 --> 00:03:35.930 Grubb, Dublin when, uh, the telescope was 89 00:03:35.930 --> 00:03:37.740 built. By the time I got there it was sir, 90 00:03:37.740 --> 00:03:40.730 uh, Howard Grubb Parsons Co. Ltd. But 91 00:03:40.730 --> 00:03:43.090 it was basically the same company amalgamated 92 00:03:43.090 --> 00:03:46.050 in 1926 with the Parsons company. So, 93 00:03:46.050 --> 00:03:48.810 um, I continued my kinship with that 94 00:03:48.810 --> 00:03:51.770 telescope and uh, uh, of course when I came 95 00:03:51.770 --> 00:03:54.370 to Australia, was interested to see it at 96 00:03:54.370 --> 00:03:57.090 stromlo. Then in 2003, 97 00:03:57.610 --> 00:04:00.290 uh, the Stromlo Observatory had that terrible 98 00:04:00.370 --> 00:04:02.730 fire, bush fire that went through, destroyed 99 00:04:02.730 --> 00:04:05.250 all the heritage buildings, including the one 100 00:04:05.600 --> 00:04:08.560 that uh, that telescope sat in, 101 00:04:08.950 --> 00:04:11.720 uh, and basically melted a lot of 102 00:04:11.720 --> 00:04:13.840 the. Well, melted the dome onto the 103 00:04:13.840 --> 00:04:16.480 telescope. The dome was aluminium, uh, and 104 00:04:16.480 --> 00:04:18.200 the telescope was wrecked, its mirror was 105 00:04:18.200 --> 00:04:21.040 smashed and all the rest of it. Uh, so I, 106 00:04:21.040 --> 00:04:23.000 When I. So I wrote a book on the history of 107 00:04:23.000 --> 00:04:24.720 telescopes which was published I think 108 00:04:25.840 --> 00:04:28.160 just after that fire because, 109 00:04:28.450 --> 00:04:31.200 um, I wrote at the end I had a whole chapter 110 00:04:31.200 --> 00:04:33.680 on this telescope and I wrote something to 111 00:04:33.680 --> 00:04:36.280 the effect that uh. The best we could hope to 112 00:04:36.280 --> 00:04:38.940 see would for it to be a static 113 00:04:38.940 --> 00:04:41.500 exhibit in a museum, just the remnants. 114 00:04:42.490 --> 00:04:45.420 Uh, but it was for a while. Well it wasn't. 115 00:04:45.420 --> 00:04:48.260 No, it stayed put in Stromlo. And it was five 116 00:04:48.260 --> 00:04:50.380 years after the fire, 2008, when this 117 00:04:50.380 --> 00:04:53.260 consortium of museums, uh, Victoria, 118 00:04:53.260 --> 00:04:56.030 the Astronomical Society of Victoria, uh, 119 00:04:56.030 --> 00:04:58.780 Royal Botanic Gardens, Melbourne, because 120 00:04:58.780 --> 00:05:01.750 that's where it started its career. Uh, 121 00:05:02.170 --> 00:05:04.900 uh, and uh. I think the Bureau of Meteorology 122 00:05:04.900 --> 00:05:07.660 were involved as well. Uh, and they 123 00:05:07.660 --> 00:05:10.480 got together a plan to basically 124 00:05:10.480 --> 00:05:12.520 restore it. Uh, and 125 00:05:13.880 --> 00:05:16.520 so I uh, did play a role in that. In 126 00:05:16.520 --> 00:05:19.400 2015 we actually held 127 00:05:19.400 --> 00:05:21.720 a workshop which I chaired, which was about 128 00:05:21.880 --> 00:05:24.160 how you could update the optics of the 129 00:05:24.160 --> 00:05:26.800 telescope because the mechanical stuff could 130 00:05:26.800 --> 00:05:29.440 be refurbished. Uh, but the 131 00:05:29.440 --> 00:05:32.250 optics were a different matter. Uh, and a uh, 132 00:05:32.320 --> 00:05:35.040 sort of optical prescription was drawn up. 133 00:05:35.040 --> 00:05:37.200 Now Those optics are still in the process of 134 00:05:37.200 --> 00:05:39.480 being manufactured. Uh, but 135 00:05:40.050 --> 00:05:43.010 the telescope itself is now 136 00:05:43.090 --> 00:05:45.930 essentially mechanically complete. It is 137 00:05:45.930 --> 00:05:48.290 as complete as it was when it was built. 138 00:05:48.930 --> 00:05:51.730 And the work that's been done, more than 100 139 00:05:52.130 --> 00:05:54.810 volunteers and staff from Museums 140 00:05:54.810 --> 00:05:56.730 Victoria and the Astronomical Society of 141 00:05:56.730 --> 00:05:59.210 Victoria, well over a hundred have worked on 142 00:05:59.210 --> 00:06:01.890 it. And so last, uh, week there was a little 143 00:06:01.890 --> 00:06:04.690 party to celebrate that. And, 144 00:06:04.780 --> 00:06:07.300 uh, some of the museum's dignitary said a few 145 00:06:07.300 --> 00:06:09.180 words, I said a few words. The chap who's 146 00:06:09.180 --> 00:06:11.460 been leading the project, Simon Brink over 147 00:06:11.460 --> 00:06:13.980 the last few years, he said a few words. He's 148 00:06:13.980 --> 00:06:16.300 actually coming to lunch with us on Saturday. 149 00:06:16.460 --> 00:06:18.500 Oh, lovely. Even though he's in Melbourne, 150 00:06:18.500 --> 00:06:21.180 he's coming up, um, which is nice. 151 00:06:21.960 --> 00:06:24.840 Um, so we had a celebration and, uh, 152 00:06:24.840 --> 00:06:26.940 to be honest, what they've done is nothing 153 00:06:26.940 --> 00:06:29.260 short of miraculous because there weren't any 154 00:06:30.300 --> 00:06:32.700 diagrams of all the bits and pieces of this 155 00:06:32.700 --> 00:06:35.060 telescope. There were engineering diagrams of 156 00:06:35.060 --> 00:06:38.060 the thing complete. They were published in a 157 00:06:38.060 --> 00:06:40.580 journal. But the individual parts and 158 00:06:40.660 --> 00:06:43.020 probably thousands of 159 00:06:43.020 --> 00:06:45.780 components, screws, washers, 160 00:06:46.320 --> 00:06:49.260 uh, pulleys, cog wheels of various 161 00:06:49.260 --> 00:06:51.980 different sized, all of that. No 162 00:06:51.980 --> 00:06:54.100 idea what they looked like. And by 163 00:06:54.500 --> 00:06:57.170 scouring photographs of the telescope, uh, 164 00:06:57.540 --> 00:07:00.020 from many sources and 165 00:07:00.820 --> 00:07:03.600 working out things like the numbers of teeth 166 00:07:03.600 --> 00:07:05.840 you need on a cogwheel to make the things 167 00:07:05.920 --> 00:07:08.840 work properly, uh, they've done a great job 168 00:07:08.840 --> 00:07:11.240 with all that. And now it's in basically in 169 00:07:11.240 --> 00:07:13.800 perfect working order, except it doesn't have 170 00:07:13.800 --> 00:07:16.000 its main mirror yet that's being fabricated. 171 00:07:16.680 --> 00:07:19.120 Um, it's at the moment still at 172 00:07:19.120 --> 00:07:21.240 Scienceworks, which is the Science M Museum 173 00:07:21.240 --> 00:07:23.600 in Victoria. And it's a big exhibit which is 174 00:07:23.600 --> 00:07:25.200 Andrew Dunkley: worth a visit, especially with the kids. 175 00:07:25.360 --> 00:07:27.680 Professor Fred Watson: Yeah, it's a great place to go. Uh, and 176 00:07:27.920 --> 00:07:29.960 anybody, uh, who does go to Melbourne and 177 00:07:29.960 --> 00:07:31.920 sees scienceworks definitely have a look at 178 00:07:31.920 --> 00:07:33.560 the great Melbourne telescope. The hope is 179 00:07:33.560 --> 00:07:35.940 that one day it will be in its original 180 00:07:35.940 --> 00:07:37.660 building, which still exists in the Royal 181 00:07:37.660 --> 00:07:40.620 Botanic Gardens. Uh, but, um, there's quite a 182 00:07:40.620 --> 00:07:43.300 bit of work needs to be done to make 183 00:07:43.300 --> 00:07:45.910 that, uh, oh, s. Uh, 184 00:07:45.910 --> 00:07:48.620 satisfactory for 2026 185 00:07:48.620 --> 00:07:51.500 or whenever it happens, compared with 186 00:07:51.500 --> 00:07:53.500 the, um, you know, the health and safety 187 00:07:53.500 --> 00:07:56.460 regulations in 1869 when people came and 188 00:07:56.460 --> 00:07:58.820 went, um, just had a look through the 189 00:07:58.820 --> 00:08:00.980 telescope. That's the idea that it will 190 00:08:00.980 --> 00:08:02.900 eventually be a working telescope for the 191 00:08:02.900 --> 00:08:04.700 public for people to come and look through. 192 00:08:05.100 --> 00:08:07.780 Andrew Dunkley: Wonderful. And, uh, if you can't get down to 193 00:08:07.780 --> 00:08:09.820 see it in Melbourne, uh, just do a search for 194 00:08:09.820 --> 00:08:11.540 the Melbourne telescope online and have a 195 00:08:11.540 --> 00:08:13.020 look at it and you'll know what we're talking 196 00:08:13.020 --> 00:08:15.100 about, um, the lattice work is just 197 00:08:15.180 --> 00:08:17.980 beautiful. It is a glorious piece of 198 00:08:17.980 --> 00:08:20.860 equipment. And I stumbled across it. I 199 00:08:20.860 --> 00:08:22.780 didn't even know it was at Science Works when 200 00:08:22.780 --> 00:08:24.460 we went there. And we just went for a wander 201 00:08:24.460 --> 00:08:26.580 and found it. And I went, oh, Fred Watson 202 00:08:26.580 --> 00:08:28.260 will love this. And then it turns out you 203 00:08:28.260 --> 00:08:29.460 were the patron, so. 204 00:08:29.460 --> 00:08:32.250 Professor Fred Watson: Yes, that's right. Yeah. Yeah. It's um, 205 00:08:32.830 --> 00:08:35.110 it is, uh, it's quite staggering. 206 00:08:35.110 --> 00:08:36.670 It's how big it is, isn't it? When you. 207 00:08:36.670 --> 00:08:37.310 Andrew Dunkley: Oh yeah. 208 00:08:37.310 --> 00:08:37.830 Professor Fred Watson: Just when you. 209 00:08:37.830 --> 00:08:38.670 Andrew Dunkley: It blows your mind. 210 00:08:38.750 --> 00:08:39.110 Professor Fred Watson: Yes. 211 00:08:39.110 --> 00:08:40.430 Andrew Dunkley: You just stand there in awe. 212 00:08:40.510 --> 00:08:43.110 Professor Fred Watson: Telescope. It was the biggest fully 213 00:08:43.110 --> 00:08:45.310 steerable telescope in the world at the time 214 00:08:45.310 --> 00:08:47.310 when, um, it was built. It wasn't the 215 00:08:47.310 --> 00:08:49.230 biggest, but it was. Biggest telescope in the 216 00:08:49.230 --> 00:08:50.350 world. But it wasn't far off. 217 00:08:50.590 --> 00:08:52.990 Andrew Dunkley: Yeah. As a good friend of mine often says, 218 00:08:52.990 --> 00:08:54.190 it's a great piece of kit. 219 00:08:54.590 --> 00:08:56.830 Professor Fred Watson: It was a great piece of kit. And hopefully it 220 00:08:56.830 --> 00:08:57.870 will be again one day. 221 00:08:58.110 --> 00:08:59.070 Andrew Dunkley: Fingers crossed. 222 00:08:59.230 --> 00:09:02.190 All right, uh, moving on. We're talking black 223 00:09:02.190 --> 00:09:04.270 holes. Very unusual. We don't usually talk 224 00:09:04.570 --> 00:09:06.250 things like this, but, uh, this, this is an 225 00:09:06.250 --> 00:09:08.030 interesting one because they, They've uh, 226 00:09:08.030 --> 00:09:09.650 made it a bit of a discovery. They've. 227 00:09:09.650 --> 00:09:11.850 They've recorded the loudest crash of 228 00:09:11.850 --> 00:09:14.170 gravitational waves ever heard. And it was 229 00:09:14.170 --> 00:09:16.730 because of two black holes that 230 00:09:16.730 --> 00:09:19.090 decided, uh, to play billiards with each 231 00:09:19.090 --> 00:09:22.050 other and boom. Uh, but 232 00:09:22.050 --> 00:09:24.770 it's what they've discovered from the. In the 233 00:09:24.770 --> 00:09:26.570 aftermath of all this that's getting 234 00:09:26.570 --> 00:09:27.210 interesting. 235 00:09:27.970 --> 00:09:30.170 Professor Fred Watson: Uh, yes, it is. Um, so, 236 00:09:30.900 --> 00:09:33.820 yep, we black, um, gravitational waves 237 00:09:33.820 --> 00:09:36.820 from colliding objects have been detectable 238 00:09:36.900 --> 00:09:39.060 by humans since 2015, 239 00:09:39.740 --> 00:09:42.260 um, with uh, the LIGO 240 00:09:42.740 --> 00:09:44.940 Laser Interferometer Gravitational Wave 241 00:09:44.940 --> 00:09:47.620 Observatory in America. And that now works 242 00:09:47.620 --> 00:09:50.580 with, uh, virgo, which is an 243 00:09:50.580 --> 00:09:53.340 Italian, uh, uh, gravitational wave 244 00:09:53.340 --> 00:09:55.620 observatory, and kagra, which is the 245 00:09:55.620 --> 00:09:58.140 Kamioka Gravitational Wave Detector in 246 00:09:58.140 --> 00:10:00.780 Japan. So those three telescopes work 247 00:10:00.780 --> 00:10:03.760 together to pick up the vibrations of space, 248 00:10:04.440 --> 00:10:06.800 uh, which are, uh, transmitted from very 249 00:10:06.800 --> 00:10:09.640 distant collisions usually. And it's usually 250 00:10:09.640 --> 00:10:12.440 neutron stars and black holes, uh, with 251 00:10:12.440 --> 00:10:14.600 collisions between either neutron stars and 252 00:10:14.600 --> 00:10:17.320 neutron stars or black holes and black holes, 253 00:10:17.320 --> 00:10:19.770 or neutron stars and black holes. Um, 254 00:10:20.000 --> 00:10:22.640 those all produce gravitational wave signals 255 00:10:22.640 --> 00:10:24.880 that are actually in the frequency range 256 00:10:25.040 --> 00:10:27.800 detectable by uh, these telescopes. 257 00:10:27.800 --> 00:10:30.440 Because that's a key part of it. The amount 258 00:10:30.440 --> 00:10:32.920 of energy that's involved tells, uh, you what 259 00:10:32.920 --> 00:10:35.020 the frequency of the gravitational waves is 260 00:10:35.020 --> 00:10:37.940 going to be. And as we've noted 261 00:10:37.940 --> 00:10:40.540 before, Andrew, it's curious that, um, 262 00:10:40.780 --> 00:10:42.980 the gravitational waves that these telescopes 263 00:10:42.980 --> 00:10:45.220 are sensitive to are actually in the audio 264 00:10:45.220 --> 00:10:48.100 frequency regime. They're basically. If you 265 00:10:48.100 --> 00:10:50.900 just amplified them, uh, you would have an 266 00:10:50.900 --> 00:10:52.900 audio signal. And that's basically what they 267 00:10:52.900 --> 00:10:54.380 do, except they're doing it in a very much 268 00:10:54.380 --> 00:10:56.890 more sophisticated way. Um, 269 00:10:57.480 --> 00:11:00.120 um. The amount of, um, 270 00:11:00.480 --> 00:11:02.920 shaking of space that they can 271 00:11:02.920 --> 00:11:04.160 detect is 272 00:11:05.360 --> 00:11:08.280 absolutely infinitesimal. Uh, but 273 00:11:08.280 --> 00:11:10.440 these things are sensitive enough that they 274 00:11:10.440 --> 00:11:13.000 can measure a distance that is a 275 00:11:13.000 --> 00:11:15.360 thousandth, I think it's a 10,000th actually, 276 00:11:15.680 --> 00:11:18.480 of the diameter of a proton. Uh, that's 277 00:11:19.200 --> 00:11:21.480 the accuracy with which they can measure the 278 00:11:21.480 --> 00:11:23.800 distance between two mirrors, which is how 279 00:11:23.800 --> 00:11:26.280 you do all this sort of thing. So that's the 280 00:11:26.280 --> 00:11:28.800 backstory. Uh, the up storey, 281 00:11:29.760 --> 00:11:32.480 the forward storey. Is that 282 00:11:32.560 --> 00:11:35.440 an object or you don't have an object, 283 00:11:35.440 --> 00:11:38.440 you have a gravitational wave signal. Uh, it 284 00:11:38.440 --> 00:11:39.680 rejoices in the name of 285 00:11:39.680 --> 00:11:42.160 GW25014. 286 00:11:42.810 --> 00:11:44.650 Uh, that tells you that it was picked up, um, 287 00:11:44.960 --> 00:11:47.630 in January, uh, 2025. Uh, 288 00:11:47.760 --> 00:11:50.560 that's where the 25011 comes 289 00:11:50.560 --> 00:11:53.200 from. Um. Uh, and it, 290 00:11:53.980 --> 00:11:56.870 uh, basically, uh, on 291 00:11:56.870 --> 00:11:59.310 analysis, um, has 292 00:12:00.110 --> 00:12:02.430 been, uh, detected to be 293 00:12:02.990 --> 00:12:05.990 a collision between two black holes, each 294 00:12:05.990 --> 00:12:08.950 of which had, uh, around 32 times the 295 00:12:08.950 --> 00:12:11.750 mass of the sun until they collided. And 296 00:12:11.750 --> 00:12:14.190 that set, uh, you know, set the 297 00:12:14.270 --> 00:12:17.230 gravitational waves on their way because it 298 00:12:17.230 --> 00:12:20.030 basically disturbed space, it rippled space. 299 00:12:21.060 --> 00:12:23.780 So what's happened is. And this, as you 300 00:12:23.780 --> 00:12:25.380 mentioned at the beginning, is the loudest 301 00:12:25.380 --> 00:12:26.980 gravitational wave signal that's been 302 00:12:26.980 --> 00:12:29.630 detected, or certainly the most, uh, 303 00:12:29.630 --> 00:12:31.780 intense. The, um, highest amplitude one. 304 00:12:31.940 --> 00:12:32.500 Andrew Dunkley: Yeah. 305 00:12:33.130 --> 00:12:35.540 Professor Fred Watson: Um, so what has happened 306 00:12:35.940 --> 00:12:38.740 is, uh, that researchers, uh, have 307 00:12:38.740 --> 00:12:41.300 analysed the audio signal, 308 00:12:41.990 --> 00:12:44.580 um, and they found in it, um, 309 00:12:45.620 --> 00:12:47.340 basically that it's been described as a 310 00:12:47.340 --> 00:12:50.330 feature, uh, which is uh, something 311 00:12:50.330 --> 00:12:53.130 called a direct wave. It's 312 00:12:53.130 --> 00:12:55.770 a component of the signal, uh, 313 00:12:56.290 --> 00:12:59.050 and it's a direct wave, uh, that 314 00:12:59.050 --> 00:13:01.330 has not. That's been seen before, 315 00:13:01.810 --> 00:13:04.769 but hasn't. Nobody's worked out what it 316 00:13:04.769 --> 00:13:07.570 is, but apparently it 317 00:13:07.570 --> 00:13:09.570 is a feature that 318 00:13:09.890 --> 00:13:12.850 essentially, uh. In 319 00:13:12.850 --> 00:13:15.250 the gravitational wave structure that comes 320 00:13:15.250 --> 00:13:18.200 from this event, you can tell this 321 00:13:18.200 --> 00:13:20.560 direct wave is to do with 322 00:13:21.200 --> 00:13:24.080 the event horizon of the combined 323 00:13:24.080 --> 00:13:26.680 black holes. So you've got two black 324 00:13:26.680 --> 00:13:29.400 holes, each of which has got its own event 325 00:13:29.400 --> 00:13:31.840 horizon. They're spinning around one another, 326 00:13:32.000 --> 00:13:34.320 getting ever closer, as we've seen that sort 327 00:13:34.320 --> 00:13:36.680 of thing before. And the frequency goes up of 328 00:13:36.680 --> 00:13:39.280 the gravitational waves, um, and then 329 00:13:39.920 --> 00:13:42.200 suddenly it all stops because they've 330 00:13:42.200 --> 00:13:44.520 collided and there's no more accelerations, 331 00:13:44.520 --> 00:13:46.760 which is what you need, uh, to set up 332 00:13:46.760 --> 00:13:49.660 gravitational waves. Um, but, 333 00:13:49.870 --> 00:13:52.620 uh, at that point the two, um, 334 00:13:52.860 --> 00:13:55.420 gravitate, sorry, the two event horizons 335 00:13:55.420 --> 00:13:55.980 merge. 336 00:13:56.880 --> 00:13:59.500 Uh, now, a recap on event horizons. That's 337 00:13:59.500 --> 00:14:01.740 the point of no return. Basically, 338 00:14:02.460 --> 00:14:04.620 it's the distance from the black hole, 339 00:14:05.180 --> 00:14:07.660 uh, where the escape velocity 340 00:14:08.320 --> 00:14:11.060 uh, is more than the speed of 341 00:14:11.060 --> 00:14:14.060 light. And so nothing can escape from 342 00:14:14.060 --> 00:14:16.470 within the event horizon. Uh, and in 343 00:14:16.470 --> 00:14:18.230 particular light can't escape. So the event 344 00:14:18.230 --> 00:14:20.230 horizon is black. It's a sphere around the 345 00:14:20.230 --> 00:14:22.510 black hole, uh, through which you can't see 346 00:14:22.510 --> 00:14:24.190 because nothing escapes, including light. 347 00:14:25.230 --> 00:14:28.150 So um, that is what the event horizon 348 00:14:28.150 --> 00:14:30.820 is. In a sense it's imaginary. Uh, uh, 349 00:14:30.820 --> 00:14:33.550 Andrew, you know it's not a real surface, 350 00:14:33.550 --> 00:14:35.870 it's an imaginary surface because it's just 351 00:14:35.870 --> 00:14:38.510 the boundary between what's visible and 352 00:14:38.510 --> 00:14:41.070 what's not visible. 353 00:14:41.550 --> 00:14:44.380 Now we know when black holes 354 00:14:44.380 --> 00:14:47.260 collide. Uh, I don't know that 355 00:14:47.260 --> 00:14:49.660 much about the details of these things but 356 00:14:49.660 --> 00:14:52.500 there is a period immediately after 357 00:14:52.500 --> 00:14:54.500 they've merged which is called the ring down. 358 00:14:54.900 --> 00:14:57.340 And it's a time when they sort of 359 00:14:57.340 --> 00:15:00.340 consolidate as one black hole. And that 360 00:15:00.340 --> 00:15:03.340 means their event horizons also consolidate. 361 00:15:03.340 --> 00:15:06.140 And I think this direct wave that has been 362 00:15:06.140 --> 00:15:08.180 detected is basically 363 00:15:09.290 --> 00:15:12.170 uh, an artefact of that ring 364 00:15:12.170 --> 00:15:14.320 down. Uh, and so um, 365 00:15:15.450 --> 00:15:18.130 what I guess is uh, perhaps the 366 00:15:18.130 --> 00:15:20.730 takeaway message from this work is not 367 00:15:21.210 --> 00:15:24.010 that we've learned something miraculous 368 00:15:24.010 --> 00:15:26.330 and new about the event horizon 369 00:15:26.730 --> 00:15:28.770 but that we've learned that there might be a 370 00:15:28.770 --> 00:15:31.130 way of, in future 371 00:15:31.130 --> 00:15:34.050 gravitational wave events uh, might be 372 00:15:34.050 --> 00:15:36.930 a way of analysing these direct waves to give 373 00:15:36.930 --> 00:15:39.530 us more information on the black hole 374 00:15:39.940 --> 00:15:42.380 event horizon. Because at the moment we don't 375 00:15:42.380 --> 00:15:45.060 know much about it. We've seen them 376 00:15:45.460 --> 00:15:48.140 in the telescopes, you know the 377 00:15:48.140 --> 00:15:50.220 um, observations from the Event Horizon 378 00:15:50.220 --> 00:15:53.140 Telescope that um, amalgam of many radio 379 00:15:53.140 --> 00:15:55.620 telescopes, an Earth sized array, 380 00:15:56.100 --> 00:15:58.780 uh, which has been used to look at the black 381 00:15:58.780 --> 00:16:01.140 holes in centre of our own galaxy. And in 382 00:16:01.140 --> 00:16:03.950 M57 I think it was uh, with um, 383 00:16:05.280 --> 00:16:08.230 uh fairly high degree of 384 00:16:08.230 --> 00:16:10.510 precision. What we've seen is the black 385 00:16:10.510 --> 00:16:13.430 shadow of the event horizon. Um 386 00:16:13.590 --> 00:16:15.830 but perhaps with these gravitational waves, 387 00:16:15.910 --> 00:16:18.750 these direct waves there might be a ah, 388 00:16:18.830 --> 00:16:21.789 way of teasing out even more detail from 389 00:16:21.789 --> 00:16:24.310 these distant and highly enigmatic 390 00:16:24.310 --> 00:16:24.950 objects. 391 00:16:25.030 --> 00:16:27.270 Andrew Dunkley: Yes, indeed. And uh, another interesting 392 00:16:27.270 --> 00:16:29.190 thing that comes out of this storey is that 393 00:16:29.270 --> 00:16:31.950 um, they're suggesting uh, the 394 00:16:31.950 --> 00:16:34.800 measurements that uh, that they've 395 00:16:34.800 --> 00:16:37.080 made could be a step towards 396 00:16:38.120 --> 00:16:40.920 future um, tests of general relativity 397 00:16:41.960 --> 00:16:44.720 using direct waves. So you know there's all 398 00:16:44.720 --> 00:16:46.520 sorts of potential by the sound of it. 399 00:16:46.760 --> 00:16:49.740 Professor Fred Watson: That's right, yeah. I mean exactly. And uh, 400 00:16:49.880 --> 00:16:52.280 of course this is one of the holy grails of 401 00:16:52.920 --> 00:16:55.000 science generally actually certainly physics 402 00:16:55.000 --> 00:16:57.680 to find chinks in general relativity 403 00:16:57.680 --> 00:17:00.570 because uh, at the moment it behaves 404 00:17:00.570 --> 00:17:02.570 exactly as predicted. Everything that we've 405 00:17:02.570 --> 00:17:05.300 seen in the universe Follows, uh, 406 00:17:05.730 --> 00:17:07.490 the rules and regulations of general 407 00:17:07.490 --> 00:17:10.370 relativity, uh, in a perfect way. 408 00:17:11.010 --> 00:17:13.850 So maybe, uh, direct waves will, as you 409 00:17:13.850 --> 00:17:16.210 said, uh, give us a way of testing general 410 00:17:16.210 --> 00:17:19.170 relativity. If we find, um, things 411 00:17:19.170 --> 00:17:22.050 that don't work in general relativity, then 412 00:17:22.050 --> 00:17:23.970 that could be an opening into new physics, 413 00:17:23.970 --> 00:17:26.010 which is certainly a hot topic at the moment. 414 00:17:26.560 --> 00:17:28.680 Andrew Dunkley: Indeed it is. Uh, well, uh, everyone, 415 00:17:28.680 --> 00:17:30.640 including Einstein, thinks something's wrong 416 00:17:30.640 --> 00:17:32.520 with it. They just. Yes, they just can't find 417 00:17:32.520 --> 00:17:34.880 anything at the moment. It keeps coming up 418 00:17:35.280 --> 00:17:37.120 aces every time they test it. 419 00:17:37.280 --> 00:17:38.920 Professor Fred Watson: Yeah, they think something's wrong with it 420 00:17:38.920 --> 00:17:41.080 because it doesn't sit with quantum 421 00:17:41.080 --> 00:17:43.640 mechanics. The two are incompatible and they 422 00:17:43.640 --> 00:17:46.120 both work perfectly well, but they're 423 00:17:46.120 --> 00:17:46.960 incompatible. 424 00:17:48.480 --> 00:17:49.280 Andrew Dunkley: Weird, isn't it? 425 00:17:49.280 --> 00:17:50.720 Professor Fred Watson: Yes, that's very weird. Yeah. 426 00:17:50.720 --> 00:17:52.560 Andrew Dunkley: The other thing that I find fascinating about 427 00:17:52.560 --> 00:17:55.240 this Storey, is that from something as simple 428 00:17:55.240 --> 00:17:57.930 as a, as a gravitational wave, 429 00:17:57.930 --> 00:18:00.770 they're able to break it down and find 430 00:18:00.770 --> 00:18:02.610 information that is 431 00:18:04.690 --> 00:18:07.650 really just. You can't 432 00:18:07.650 --> 00:18:10.130 see any of this. It's all just data, isn't 433 00:18:10.130 --> 00:18:10.330 it? 434 00:18:10.330 --> 00:18:12.290 Professor Fred Watson: Yeah, yeah, that's correct. That's right. 435 00:18:12.290 --> 00:18:14.770 But, uh, the physics is well understood 436 00:18:14.770 --> 00:18:17.090 because general relativity is such a reliable 437 00:18:17.570 --> 00:18:19.930 tool for people to use to analyse these 438 00:18:19.930 --> 00:18:22.370 things. Um, that's how we can make these 439 00:18:22.980 --> 00:18:25.940 statements about it. And yes, um, if we can 440 00:18:25.940 --> 00:18:27.900 find flaws with general relativity, it will 441 00:18:27.900 --> 00:18:30.740 be very exciting indeed it will. 442 00:18:30.740 --> 00:18:33.580 Andrew Dunkley: And you can read all about it@the space.com 443 00:18:33.580 --> 00:18:35.780 website. Uh, they publish their research, 444 00:18:36.370 --> 00:18:39.340 uh, in the journal Nature. This 445 00:18:39.340 --> 00:18:41.860 is Space Nuts with Andrew Dunkley and 446 00:18:41.940 --> 00:18:43.780 Professor Fred Watson Watson. 447 00:18:45.780 --> 00:18:47.820 Professor Fred Watson: I believe that this nation should commit 448 00:18:47.820 --> 00:18:50.050 Andrew Dunkley: itself to achieving the goal, 449 00:18:50.690 --> 00:18:53.610 before this decade is out, of landing a 450 00:18:53.610 --> 00:18:53.810 man 451 00:18:53.810 --> 00:18:56.170 Professor Fred Watson: on the moon and returning him safely to the 452 00:18:56.170 --> 00:18:56.490 Earth. 453 00:18:56.490 --> 00:18:57.330 Andrew Dunkley: These nuts. 454 00:18:58.210 --> 00:19:01.130 Now, Fred Watson, we turn our, uh, attention 455 00:19:01.130 --> 00:19:03.730 towards China. Uh, of course, they've got a 456 00:19:03.970 --> 00:19:06.930 very active space station in operation 457 00:19:06.930 --> 00:19:09.490 at the moment. Uh, the latest news though is 458 00:19:09.490 --> 00:19:12.170 that they intend to, uh, make it 459 00:19:12.170 --> 00:19:14.530 bigger and at the same time they're going to 460 00:19:14.530 --> 00:19:17.190 put a new space telescope into, uh, into 461 00:19:17.190 --> 00:19:19.270 orbit as well. So, uh, they're really going 462 00:19:19.270 --> 00:19:20.950 ahead in leaps and bounds, aren't they? 463 00:19:21.750 --> 00:19:24.110 Professor Fred Watson: They are, yes. Uh, it's, um. You know, this 464 00:19:24.110 --> 00:19:26.630 is part of the Chinese. It's not the China 465 00:19:26.630 --> 00:19:29.260 national, uh, Space Agency. 466 00:19:29.260 --> 00:19:31.350 Uh, I think it's that they've got a separate 467 00:19:31.909 --> 00:19:34.550 space agency for human space flight. 468 00:19:35.040 --> 00:19:37.630 Uh, and that's the organisation that 469 00:19:37.630 --> 00:19:40.550 operates the Tiangong, uh, space Station, 470 00:19:40.550 --> 00:19:43.310 which has been up there since 2021, I think 471 00:19:43.310 --> 00:19:45.980 was when, uh, we started seeing it being 472 00:19:45.980 --> 00:19:48.500 assembled. It was assembled in a very similar 473 00:19:48.500 --> 00:19:50.700 manner to the International Space Station by 474 00:19:51.020 --> 00:19:54.020 building sort of modules that you can stick 475 00:19:54.020 --> 00:19:57.020 together like Lego, uh, up once 476 00:19:57.120 --> 00:19:58.780 uh, these modules are in orbit. 477 00:19:58.940 --> 00:20:01.020 Andrew Dunkley: Yeah. And at the moment it's the China 478 00:20:01.020 --> 00:20:03.820 National Space Administration which handles 479 00:20:03.820 --> 00:20:06.060 the programmes, and the China Manned Space 480 00:20:06.060 --> 00:20:08.380 Agency which um, oversees human 481 00:20:08.380 --> 00:20:09.100 spaceflight. 482 00:20:09.740 --> 00:20:12.100 Professor Fred Watson: That's right. I knew there were two 483 00:20:12.100 --> 00:20:13.980 organisations involved. Thank you for that. 484 00:20:14.140 --> 00:20:14.700 Andrew Dunkley: That's all right. 485 00:20:15.060 --> 00:20:17.670 Professor Fred Watson: Um, so, uh, 486 00:20:17.670 --> 00:20:20.380 yes, so uh, at the moment the, 487 00:20:20.380 --> 00:20:22.700 the Tiangong consists of three 488 00:20:22.780 --> 00:20:25.780 modules and they're arranged in a sort of T 489 00:20:25.780 --> 00:20:27.780 shape, uh, with um. 490 00:20:28.560 --> 00:20:30.940 Uh, two, three. The, the three 491 00:20:31.740 --> 00:20:33.740 end points of the modules if you like, 492 00:20:33.740 --> 00:20:36.020 coming, coming together in a, in a sort of 493 00:20:36.020 --> 00:20:38.420 vestibule where you can uh, tunnel your way 494 00:20:38.420 --> 00:20:40.940 from one to the, to the other with these 495 00:20:41.380 --> 00:20:43.570 uh, basically entry and exit hatches. That 496 00:20:43.900 --> 00:20:46.330 uh, is the way things work on the 497 00:20:46.330 --> 00:20:48.890 International Space Station as well. But as 498 00:20:48.890 --> 00:20:51.130 you've said, uh, what they're now planning to 499 00:20:51.130 --> 00:20:53.490 do is to add three more 500 00:20:53.490 --> 00:20:56.490 modules. Um and the reason they 501 00:20:56.490 --> 00:20:59.470 want to do that is because uh, 502 00:20:59.810 --> 00:21:02.370 they want to do more research up there, 503 00:21:02.980 --> 00:21:05.970 uh, and make more frequent crew and 504 00:21:05.970 --> 00:21:08.930 cargo changes. Um, so they're 505 00:21:08.930 --> 00:21:11.930 actually, I think the way to deal 506 00:21:11.930 --> 00:21:14.170 with that is to make the space station 507 00:21:14.170 --> 00:21:17.170 bigger. Um, and so it's going to be 508 00:21:17.330 --> 00:21:20.210 what they're calling a double T shape, which 509 00:21:20.210 --> 00:21:22.290 I think is probably an H shape 510 00:21:23.410 --> 00:21:25.610 if I can put it that way. Um, well that's 511 00:21:25.610 --> 00:21:25.969 what it. 512 00:21:25.969 --> 00:21:27.570 Andrew Dunkley: Yeah, it would turn into that, wouldn't it? 513 00:21:27.570 --> 00:21:29.970 Professor Fred Watson: You'd expect so. Yes, that's right. Unless 514 00:21:29.970 --> 00:21:32.970 they do something clever, uh, like turn 515 00:21:32.970 --> 00:21:35.730 one of the T's round, uh right angles to the 516 00:21:35.730 --> 00:21:37.770 other one. Anyway, we don't know what's going 517 00:21:37.770 --> 00:21:40.220 to happen there. But um, there is a new 518 00:21:40.780 --> 00:21:43.180 multipurpose um, module and two 519 00:21:43.500 --> 00:21:46.220 new experimental modules that are planned 520 00:21:46.530 --> 00:21:49.200 uh, to um, essentially uh, 521 00:21:49.340 --> 00:21:51.980 you know, allow Chinese 522 00:21:52.230 --> 00:21:54.820 uh, space exploration in low Earth 523 00:21:54.820 --> 00:21:57.660 orbit to continue and be extended. 524 00:21:58.450 --> 00:22:01.020 Um, um, we understand from 525 00:22:01.320 --> 00:22:03.740 um, some of the researchers in China 526 00:22:04.300 --> 00:22:07.290 that uh, it's always been 527 00:22:07.640 --> 00:22:10.170 uh, an expectation that this 528 00:22:10.250 --> 00:22:12.490 would take place, that there'd be this 529 00:22:12.490 --> 00:22:15.330 extension. Uh, and what it will do in 530 00:22:15.330 --> 00:22:18.250 terms of the mass of the um, space 531 00:22:18.250 --> 00:22:20.610 station is take it up from its current 90 532 00:22:20.610 --> 00:22:22.810 tonnes, uh up to 533 00:22:23.690 --> 00:22:26.650 180 tonnes or thereabouts. And there's a 534 00:22:26.650 --> 00:22:28.570 yardstick, if I remember rightly, and you 535 00:22:28.570 --> 00:22:30.530 might be able to correct me here Andrew, but 536 00:22:30.530 --> 00:22:32.370 I think the International Space station is 537 00:22:32.370 --> 00:22:34.890 about 400 tonnes in terms of its mass. 538 00:22:35.530 --> 00:22:38.190 I think that is the case. So uh, 539 00:22:38.310 --> 00:22:41.190 that's uh, the plan and 540 00:22:41.430 --> 00:22:44.270 alongside that, as you've already mentioned 541 00:22:44.270 --> 00:22:46.870 Andrew, is the idea of a new 542 00:22:47.630 --> 00:22:50.270 um, space observatory, an optical 543 00:22:50.270 --> 00:22:53.069 Telescope quite similar in some 544 00:22:53.069 --> 00:22:55.550 ways to the Hubble Space Telescope. A 545 00:22:55.550 --> 00:22:58.150 slightly smaller mirror, 2 metres rather than 546 00:22:58.150 --> 00:22:59.350 2.3 metres, 547 00:23:01.110 --> 00:23:03.950 um, and also with a much wider 548 00:23:03.950 --> 00:23:06.830 field of view. The Hubble has quite a narrow 549 00:23:06.830 --> 00:23:09.490 field of view. Uh, and in fact the Nancy 550 00:23:09.490 --> 00:23:12.370 Grace Roman telescope, which is also very 551 00:23:12.370 --> 00:23:14.930 similar to the Hubble, will have a much wider 552 00:23:14.930 --> 00:23:16.690 field of view than Hubble. That's being 553 00:23:16.690 --> 00:23:18.610 launched later this year, I hope. 554 00:23:19.170 --> 00:23:21.650 Um, this, uh, Chinese 555 00:23:21.650 --> 00:23:24.570 telescope, uh, which has a name, Shuntian, 556 00:23:24.570 --> 00:23:27.450 I think, is probably how it's 557 00:23:27.450 --> 00:23:30.210 pronounced in my, 558 00:23:30.230 --> 00:23:32.850 um, poor Chinese, uh, poor 559 00:23:32.850 --> 00:23:34.530 Mandarin and poor Chinese. 560 00:23:35.690 --> 00:23:38.690 Um, it's got a much bigger field of view and 561 00:23:38.690 --> 00:23:41.690 will actually give new, uh, 562 00:23:41.690 --> 00:23:43.750 surveys to Chinese, uh, 563 00:23:44.200 --> 00:23:46.400 astronomers. We'll see a lot more 564 00:23:46.880 --> 00:23:48.720 information about the universe coming from 565 00:23:48.720 --> 00:23:50.320 this telescope. The more telescopes you've 566 00:23:50.320 --> 00:23:52.650 got on the universe, the better. And, uh, 567 00:23:52.720 --> 00:23:55.690 Shuntian will be one of those, uh, 568 00:23:55.690 --> 00:23:58.560 features when it is launched and actually 569 00:23:58.640 --> 00:24:01.320 commissioned, uh, that will, we hope, um, 570 00:24:01.440 --> 00:24:04.200 really bring new insights into our knowledge 571 00:24:04.200 --> 00:24:04.640 of space. 572 00:24:04.880 --> 00:24:07.440 Andrew Dunkley: Yeah. Apparently its field of view 573 00:24:07.680 --> 00:24:10.520 is going to be massive compared to 574 00:24:10.520 --> 00:24:12.160 Hubble at 300 times. 575 00:24:12.480 --> 00:24:14.920 Professor Fred Watson: Correct? Yes, that's right. So it's a wide 576 00:24:14.920 --> 00:24:17.320 angle telescope rather than the sort of 577 00:24:17.320 --> 00:24:19.360 pinpoint view of the Hubble. 578 00:24:19.520 --> 00:24:21.800 Andrew Dunkley: Yeah, quite incredible. Uh, you were right 579 00:24:21.800 --> 00:24:23.940 about the International space station. Uh, 580 00:24:23.940 --> 00:24:26.720 419,700 kilogrammes 581 00:24:26.720 --> 00:24:29.680 is its mass, or say 420, 582 00:24:30.760 --> 00:24:33.720 um, tonnes. Yes, indeed. Um, the 583 00:24:33.720 --> 00:24:35.720 other interesting thing that China's working 584 00:24:35.720 --> 00:24:38.000 on, uh, is a new, 585 00:24:38.160 --> 00:24:41.130 um, um, delivery system for their. They 586 00:24:41.130 --> 00:24:42.610 call them taika nauts, don't they? 587 00:24:42.850 --> 00:24:44.210 Professor Fred Watson: Yes, they do, yeah. 588 00:24:44.860 --> 00:24:46.450 Andrew Dunkley: Uh, they want to. They want to develop a 589 00:24:46.450 --> 00:24:49.370 rocket system that will send seven up at a 590 00:24:49.370 --> 00:24:49.650 time. 591 00:24:49.650 --> 00:24:52.650 Professor Fred Watson: Yes, yeah, seven up. 592 00:24:52.650 --> 00:24:55.570 Andrew Dunkley: No, I'm joking. But, um, again, yeah, that's 593 00:24:55.570 --> 00:24:57.130 what they're looking at doing at the moment. 594 00:24:57.130 --> 00:24:58.690 They can only send up three at a time. 595 00:24:59.170 --> 00:25:01.460 Professor Fred Watson: Yes. So the Chinese, um, 596 00:25:02.300 --> 00:25:04.130 uh, orbital 597 00:25:04.980 --> 00:25:07.300 vehicle for getting astronauts up, 598 00:25:07.380 --> 00:25:09.220 Taikonauts up there. And 599 00:25:10.180 --> 00:25:11.740 I'm ashamed that I can't remember what it's 600 00:25:11.740 --> 00:25:13.700 called. Uh, is it Shenzhou? 601 00:25:14.100 --> 00:25:16.980 Shenzhou, I can't remember. Um, 602 00:25:16.980 --> 00:25:19.780 but that is basically an adaptation 603 00:25:20.340 --> 00:25:22.420 of the old Soyuts Russian 604 00:25:22.580 --> 00:25:25.020 spacecraft which is still in service in the 605 00:25:25.020 --> 00:25:26.780 International Space Station. Developed in the 606 00:25:26.780 --> 00:25:29.460 1960s. A, uh, three person, 607 00:25:29.820 --> 00:25:32.660 uh, module. Uh, I think I'm right in 608 00:25:32.660 --> 00:25:34.860 saying that the crew Dragon can take up to 609 00:25:34.860 --> 00:25:36.910 seven astronauts as well. 610 00:25:36.990 --> 00:25:38.830 Andrew Dunkley: Interesting. Shenzhou. 611 00:25:38.990 --> 00:25:40.070 Professor Fred Watson: Shenzhou, yeah. 612 00:25:40.070 --> 00:25:41.830 Andrew Dunkley: Is the, um, is the system they 613 00:25:41.830 --> 00:25:42.670 Professor Fred Watson: used at the moment. 614 00:25:43.230 --> 00:25:45.400 You did m. So, uh, 615 00:25:46.110 --> 00:25:48.430 yes. So that will go from three to seven. 616 00:25:48.670 --> 00:25:50.870 It's understandable, you know, if you Want to 617 00:25:50.870 --> 00:25:52.870 keep the crews coming and going. I think this 618 00:25:52.870 --> 00:25:54.750 is a really important development because, 619 00:25:55.410 --> 00:25:58.230 um, if nothing else, it's going to, I 620 00:25:58.230 --> 00:26:00.060 think, spur, uh, 621 00:26:01.080 --> 00:26:03.760 the private sector, um, to pick up the 622 00:26:03.760 --> 00:26:06.360 baton of what you might call Western 623 00:26:06.520 --> 00:26:08.880 International Space Stations or the Western 624 00:26:08.880 --> 00:26:11.040 International Space Station, because that's 625 00:26:11.040 --> 00:26:13.800 scheduled at the moment to be decommissioned 626 00:26:13.800 --> 00:26:16.640 in 2030. That might change. But 627 00:26:16.640 --> 00:26:18.920 it's a possibility that we will lose the ISS 628 00:26:19.160 --> 00:26:22.160 in 2030. And we've seen problems 629 00:26:22.160 --> 00:26:24.960 with the leakage that we had in one of the 630 00:26:24.960 --> 00:26:27.760 modules a couple of weeks ago where the 631 00:26:27.760 --> 00:26:30.440 crew was evacuated, not evacuated, but 632 00:26:30.440 --> 00:26:32.670 moved. The American crew, 633 00:26:33.230 --> 00:26:35.900 uh, the NASA end of the spacecraft 634 00:26:35.900 --> 00:26:38.820 were moved into a crew Dragon capsule 635 00:26:38.820 --> 00:26:41.700 to uh, just be certain that 636 00:26:41.700 --> 00:26:44.530 nothing untoward was going to happen, uh, 637 00:26:44.530 --> 00:26:47.260 if there was a catastrophic 638 00:26:47.260 --> 00:26:49.940 leak, uh, when the Roscosmos, 639 00:26:50.100 --> 00:26:52.220 cosmonauts, they were actually trying to fix 640 00:26:52.220 --> 00:26:54.420 the leak, uh, they moved the other crew, 641 00:26:55.230 --> 00:26:57.940 um, into the crew Dragon capsule for safety. 642 00:26:58.020 --> 00:27:00.690 Andrew Dunkley: Yeah, uh, in terms of replacing the iss, 643 00:27:01.570 --> 00:27:04.210 there are no firm plans at the moment, but 644 00:27:04.450 --> 00:27:06.770 they're kind of thinking about, 645 00:27:07.320 --> 00:27:09.810 um, I think you mentioned it, the commercial 646 00:27:09.810 --> 00:27:11.010 sector getting involved. 647 00:27:12.770 --> 00:27:14.850 And that's probably logical. 648 00:27:15.570 --> 00:27:18.290 I'm pretty sure that, uh, Elon would be 649 00:27:18.290 --> 00:27:21.010 pretty keen to put a space station into orbit 650 00:27:21.010 --> 00:27:23.730 and a few others probably. 651 00:27:23.730 --> 00:27:25.480 There's plenty of people around with uh, 652 00:27:25.480 --> 00:27:26.670 megabucks to do it. 653 00:27:27.300 --> 00:27:30.140 Professor Fred Watson: Yes, that's right. Um, um, but, uh, you 654 00:27:30.140 --> 00:27:32.180 know, you might think, have to think 655 00:27:32.180 --> 00:27:35.180 carefully about whether you, uh, take 656 00:27:35.180 --> 00:27:37.940 over the old, uh, the old tired 657 00:27:38.580 --> 00:27:41.360 and quite dodgy old, uh, 658 00:27:41.620 --> 00:27:43.340 International Space Station or whether you 659 00:27:43.340 --> 00:27:46.060 build something new. Um, and uh, of course 660 00:27:46.060 --> 00:27:47.940 the technology's moved on enormously since 661 00:27:47.940 --> 00:27:50.660 the 1990s when that was put together. 662 00:27:50.820 --> 00:27:53.740 It's been continuously occupied since 663 00:27:53.740 --> 00:27:56.600 2000. Uh, that's 26 664 00:27:56.600 --> 00:27:59.240 years of, um, tenants coming and going. It's 665 00:27:59.240 --> 00:28:01.080 probably taken a fair beating inside. 666 00:28:01.240 --> 00:28:03.000 Andrew Dunkley: Yeah, I'm sure they've had a few parties. 667 00:28:03.000 --> 00:28:04.280 Yeah, no doubt about it. 668 00:28:06.130 --> 00:28:08.430 Uh, if you want to uh, read all about, uh, 669 00:28:08.440 --> 00:28:09.840 China's plans, you can do 670 00:28:09.840 --> 00:28:12.640 that@space.com. uh, this is 671 00:28:12.640 --> 00:28:14.960 Space Nuts with Andrew Dunkley and Professor 672 00:28:14.960 --> 00:28:15.720 Fred Watson Watson. 673 00:28:18.360 --> 00:28:21.080 Space Nuts, our final 674 00:28:21.080 --> 00:28:23.320 storey. Fred Watson takes us close to home. 675 00:28:23.480 --> 00:28:26.440 And this is really quite a fascinating storey 676 00:28:26.520 --> 00:28:29.300 because it talks about a star, not 677 00:28:29.300 --> 00:28:32.220 our sun. Ah, another star that got 678 00:28:32.220 --> 00:28:35.140 up close and personal, um, with 679 00:28:35.140 --> 00:28:38.060 our particular, uh, sun, um, a 680 00:28:38.060 --> 00:28:40.780 little while ago. But the 681 00:28:40.780 --> 00:28:42.820 effects of that interaction, 682 00:28:43.780 --> 00:28:45.860 uh, seem to still exist, 683 00:28:46.580 --> 00:28:47.700 which is very odd. 684 00:28:47.860 --> 00:28:50.500 Professor Fred Watson: Yeah, well, that's right. Uh, yes, it is, 685 00:28:50.500 --> 00:28:53.430 it's an interesting storey. It covers two 686 00:28:53.430 --> 00:28:55.750 quite different bits of astronomy here that 687 00:28:55.750 --> 00:28:57.990 come together to sort of work out what was 688 00:28:57.990 --> 00:29:00.750 going on. So this star in question, 689 00:29:01.230 --> 00:29:02.910 it's got the glorious name of 690 00:29:02.910 --> 00:29:05.670 HD7977. HD 691 00:29:05.670 --> 00:29:07.390 stands for Henry Draper. It's one of the 692 00:29:07.390 --> 00:29:09.910 early star catalogues, uh, from the 19th 693 00:29:09.910 --> 00:29:12.590 century I think, uh, the Henry Draper 694 00:29:12.590 --> 00:29:15.390 catalogue. Uh, and it's a relatively 695 00:29:15.390 --> 00:29:18.150 near star, similar to the 696 00:29:18.150 --> 00:29:20.860 sun. Uh, it's currently in the constellation 697 00:29:20.860 --> 00:29:23.660 of Cassiopeia, which is um, one of my 698 00:29:23.660 --> 00:29:25.300 favourite northern constellations. Actually. 699 00:29:25.300 --> 00:29:27.820 It's one that we don't see from down here in 700 00:29:27.820 --> 00:29:30.740 Australia. Uh, so, 701 00:29:30.930 --> 00:29:33.540 um, how do we know that 702 00:29:33.540 --> 00:29:36.250 HD7977 had um, 703 00:29:36.420 --> 00:29:39.060 a near miss with our solar system? 704 00:29:39.540 --> 00:29:42.380 And the answer is with the Gaia mission. 705 00:29:42.380 --> 00:29:45.380 So Gaia is a spacecraft. Uh, 706 00:29:45.540 --> 00:29:47.790 it sits at the um, uh, 707 00:29:48.890 --> 00:29:51.650 sun, Earth, uh, L2 point, that's 708 00:29:51.650 --> 00:29:54.170 the Lagrange point, on the opposite side of 709 00:29:54.170 --> 00:29:56.890 the Earth from the sun. Um, it's been 710 00:29:57.130 --> 00:29:59.570 working for, I think, certainly more than a 711 00:29:59.570 --> 00:30:02.410 decade. And what it's done is measured 712 00:30:02.490 --> 00:30:05.210 star positions with absolutely 713 00:30:05.210 --> 00:30:07.850 exquisite precision. Uh, you're talking 714 00:30:07.850 --> 00:30:10.210 about, I think it's sort of some 715 00:30:10.210 --> 00:30:12.890 accuracies in the region of 100 millionths of 716 00:30:12.890 --> 00:30:15.180 an arc second. These are phenomenal 717 00:30:15.660 --> 00:30:17.900 accuracies. And an arc second of course is 718 00:30:17.900 --> 00:30:20.600 1-3600th of a degree, uh, 719 00:30:20.620 --> 00:30:23.500 the size of a, here In Australia, a $1 coin 720 00:30:23.500 --> 00:30:25.700 held up at five kilometres. It's a tiny 721 00:30:25.700 --> 00:30:27.900 angle, but this thing's measuring 722 00:30:28.620 --> 00:30:30.620 millionths of that basically, or 100 723 00:30:30.620 --> 00:30:33.500 millions. Uh, and what that does is it 724 00:30:33.500 --> 00:30:35.940 allows you, if you make these measurements at 725 00:30:35.940 --> 00:30:38.500 different times, it allows you to plot the 726 00:30:38.500 --> 00:30:41.210 motions of stars, 727 00:30:41.530 --> 00:30:44.410 uh, not just in our own galaxy and in our own 728 00:30:44.410 --> 00:30:46.890 neighbourhood, but also in the Two 729 00:30:46.890 --> 00:30:49.450 Magellanic Clouds, uh, the two 730 00:30:49.450 --> 00:30:52.250 nearest neighbour dwarf galaxies, the big 731 00:30:52.250 --> 00:30:54.690 ones, Large and Small Magellanic Clouds 732 00:30:54.690 --> 00:30:57.490 165 and 200,000 light 733 00:30:57.490 --> 00:31:00.250 years away respectively. Uh, those, 734 00:31:00.490 --> 00:31:02.850 uh, you can detect the motions of stars in 735 00:31:02.850 --> 00:31:05.810 those galaxies. And even in the Andromeda 736 00:31:05.810 --> 00:31:08.250 galaxy, about 2 1/2 million light years away, 737 00:31:08.250 --> 00:31:10.770 you can see evidence of what we call lateral 738 00:31:10.770 --> 00:31:13.110 motion on the sky, sideways motion of things. 739 00:31:13.190 --> 00:31:15.870 And if you can measure the radial velocity, 740 00:31:15.870 --> 00:31:18.110 that's the velocity along the line of sight, 741 00:31:18.110 --> 00:31:20.430 which is actually much easier if you can do 742 00:31:20.430 --> 00:31:22.910 that as well. You've got, um, the three 743 00:31:22.910 --> 00:31:25.550 dimensional motion of objects in space. And 744 00:31:25.550 --> 00:31:27.570 that is how, uh, 745 00:31:28.070 --> 00:31:30.830 HD7977 was picked 746 00:31:30.830 --> 00:31:33.270 up as having passed close to the sun 747 00:31:33.750 --> 00:31:36.390 about two and a half million years ago. 748 00:31:37.030 --> 00:31:39.150 As both these stars, The sun and 749 00:31:39.150 --> 00:31:42.030 HD7977, as they both orbit around the 750 00:31:42.030 --> 00:31:44.970 centre of our galaxy. Uh, we still 751 00:31:44.970 --> 00:31:47.970 don't know exactly how close. Uh, the data 752 00:31:47.970 --> 00:31:50.290 from Gaia suggests It was between 753 00:31:50.850 --> 00:31:53.250 4,000 and 25,000 754 00:31:53.330 --> 00:31:55.970 astronomical units. And as we've mentioned 755 00:31:55.970 --> 00:31:57.930 before, an astronomical unit is the distance 756 00:31:57.930 --> 00:32:00.770 between the Earth and the sun. Um, convenient 757 00:32:00.770 --> 00:32:03.730 measure it is uh, 150 million kilometres. 758 00:32:04.310 --> 00:32:06.210 Um, they may have 759 00:32:07.050 --> 00:32:09.930 um, we might be able to 760 00:32:09.930 --> 00:32:12.890 tie that close approach down though by other 761 00:32:12.890 --> 00:32:15.610 methods. And the methods in question 762 00:32:16.090 --> 00:32:19.050 have been employed by uh, some 763 00:32:19.050 --> 00:32:21.370 scientists at the University of 764 00:32:21.370 --> 00:32:24.330 Bordeaux. Uh, and basically 765 00:32:24.410 --> 00:32:27.410 what they have done is looked not 766 00:32:27.410 --> 00:32:30.010 at Gaia data to try and refine 767 00:32:30.450 --> 00:32:33.210 uh, this sort of look back in 768 00:32:33.210 --> 00:32:35.810 time as to when these two stars were close 769 00:32:35.810 --> 00:32:38.090 together. They've looked at long period 770 00:32:38.090 --> 00:32:40.890 comets, comets that uh, come in 771 00:32:40.890 --> 00:32:43.250 from the very furthest reaches of the solar 772 00:32:43.250 --> 00:32:45.820 system where we think there is a 773 00:32:45.820 --> 00:32:47.940 reservoir of comets. We call it the Oort 774 00:32:47.940 --> 00:32:50.820 Cloud. Uh, and it turns out that 775 00:32:50.820 --> 00:32:53.060 if you look at long period comets, 776 00:32:53.620 --> 00:32:56.540 uh, which have been measured over the 777 00:32:56.540 --> 00:32:59.540 past hundred years I guess, um, then 778 00:32:59.540 --> 00:33:02.100 you get uh, an idea 779 00:33:02.580 --> 00:33:04.820 of the distribution of their orbits. 780 00:33:05.620 --> 00:33:08.620 And basically there's a quote here 781 00:33:08.620 --> 00:33:11.460 from one of the authors uh, of 782 00:33:11.460 --> 00:33:14.420 the paper that we're talking about uh, who 783 00:33:14.420 --> 00:33:16.340 says the distribution of comet orbits 784 00:33:16.340 --> 00:33:18.800 suggests we living through an unusual time 785 00:33:19.280 --> 00:33:21.800 where HD 7977 has 786 00:33:21.800 --> 00:33:24.560 dominated the generation of new comets 787 00:33:25.040 --> 00:33:27.480 and not the larger gravitational field of the 788 00:33:27.480 --> 00:33:30.080 Milky Way as it usually would. This would 789 00:33:30.080 --> 00:33:31.800 also mean we're living through the late 790 00:33:31.800 --> 00:33:34.640 stages of a pretty rare and powerful 791 00:33:34.640 --> 00:33:37.360 comet shower. And so what they've done 792 00:33:37.360 --> 00:33:40.170 is made computer simulations of uh, 793 00:33:40.560 --> 00:33:43.440 how comet orbits might behave 794 00:33:44.080 --> 00:33:46.760 as a result of being tipped out of the Oort 795 00:33:46.760 --> 00:33:49.500 cloud by the passage of this star HD 796 00:33:49.500 --> 00:33:52.420 7977. They've kicked out the Oort cloud 797 00:33:52.420 --> 00:33:54.780 and heading towards the sun. Uh, they've 798 00:33:54.780 --> 00:33:57.620 measured uh, basically the details of 799 00:33:57.620 --> 00:34:00.500 112 long period comets. Actually they've 800 00:34:00.500 --> 00:34:02.420 chosen ones that have only been observed in 801 00:34:02.420 --> 00:34:05.020 recent years, since 1989 because 802 00:34:05.420 --> 00:34:08.260 that's when we could detect comets coming 803 00:34:08.260 --> 00:34:11.040 from uh, any part of the sky. Uh, 804 00:34:11.500 --> 00:34:13.660 if you only limit yourself to one part of the 805 00:34:13.660 --> 00:34:16.020 sky then you've got uh, as visible for 806 00:34:16.020 --> 00:34:18.700 example by a single observatory, uh, or even 807 00:34:18.700 --> 00:34:20.460 as visible by the Northern Hemisphere 808 00:34:20.460 --> 00:34:23.180 observatory. You're missing uh, 809 00:34:23.180 --> 00:34:25.480 half the objects that you want to see. And 810 00:34:25.480 --> 00:34:27.360 since what you're doing is looking at the 811 00:34:27.360 --> 00:34:29.760 statistical distribution of these things, you 812 00:34:29.760 --> 00:34:32.600 can't afford to um, eliminate 813 00:34:32.600 --> 00:34:34.720 things that way. It's what would be called a 814 00:34:34.720 --> 00:34:37.680 selection effect. Um, so yes these 815 00:34:37.680 --> 00:34:40.120 long period comets they've got very elongated 816 00:34:40.120 --> 00:34:43.120 Orbits, uh, and the suggestion is that the 817 00:34:43.120 --> 00:34:46.000 distribution of those orbits in relation to 818 00:34:46.000 --> 00:34:47.400 the direction that we know 819 00:34:47.640 --> 00:34:50.560 HD7977 went through the solar system or 820 00:34:50.560 --> 00:34:53.259 went close to the solar system. Uh, that's 821 00:34:53.259 --> 00:34:56.019 why they believe, uh, that the two 822 00:34:56.019 --> 00:34:58.659 events, uh, um, the close 823 00:34:58.739 --> 00:35:01.700 passage of 7977, uh, 824 00:35:01.939 --> 00:35:04.939 tipped up the comets and caused a lot more of 825 00:35:04.939 --> 00:35:07.819 these comets to come in. And if you 826 00:35:07.819 --> 00:35:10.790 accept uh, their hypothesis, 827 00:35:10.790 --> 00:35:13.459 um, then what it does is, 828 00:35:13.459 --> 00:35:16.179 ties down rather 829 00:35:16.179 --> 00:35:18.819 better the distance that we estimate 830 00:35:19.219 --> 00:35:21.750 HD7977, uh, 831 00:35:22.259 --> 00:35:25.040 approach the sun at somewhere 832 00:35:25.040 --> 00:35:28.000 between 6,000 and 10,000 astronomical units. 833 00:35:28.240 --> 00:35:30.880 A tighter window compared with the 4,000 to 834 00:35:30.880 --> 00:35:33.360 25,000 astronomical units that Gaia 835 00:35:33.440 --> 00:35:36.400 suggests. Yes, uh, so, uh, it's a nice 836 00:35:36.400 --> 00:35:38.320 tightening up of our uh, understanding of 837 00:35:38.320 --> 00:35:41.080 this hypothesised but probably 838 00:35:41.080 --> 00:35:43.360 real event 2 1/2 million years ago. 839 00:35:43.600 --> 00:35:45.640 Andrew Dunkley: And just to give people a bit of an idea of 840 00:35:45.640 --> 00:35:48.120 the distance, so somewhere between 6 and 841 00:35:48.120 --> 00:35:50.000 10,000 AU is where 842 00:35:50.000 --> 00:35:52.840 HD7977 and kind 843 00:35:52.840 --> 00:35:54.560 of grazed our uh, solar system. 844 00:35:54.560 --> 00:35:55.000 Professor Fred Watson: Yes. 845 00:35:55.320 --> 00:35:57.560 Andrew Dunkley: Voyager 1 is 170 846 00:35:57.800 --> 00:36:00.280 AU from Earth. So 847 00:36:00.600 --> 00:36:02.120 we're talking a fair way out. 848 00:36:02.120 --> 00:36:03.560 Professor Fred Watson: It's a long way off. That's right. 849 00:36:04.040 --> 00:36:06.080 Andrew Dunkley: You're talking probably getting into the 850 00:36:06.080 --> 00:36:08.360 vicinity of the Oort cloud, which makes sense 851 00:36:08.360 --> 00:36:11.280 given what they're hypothesising in 852 00:36:11.280 --> 00:36:11.880 this paper. 853 00:36:12.680 --> 00:36:15.440 Professor Fred Watson: Exactly right. So a star passing nearby the 854 00:36:15.440 --> 00:36:18.360 Oort cloud would definitely upset it and 855 00:36:18.360 --> 00:36:20.770 send stuff in towards the, the inner solar 856 00:36:20.770 --> 00:36:23.610 system. Yes, it's actually um, it's a theory 857 00:36:23.610 --> 00:36:25.930 that, uh, that general mechanism 858 00:36:26.410 --> 00:36:28.610 was proposed by colleagues of mine in the 859 00:36:28.610 --> 00:36:30.370 Royal Observatory in Edinburgh, Victor Klub 860 00:36:30.370 --> 00:36:32.730 and Bill Napier, back in the late 1970s. 861 00:36:33.130 --> 00:36:36.130 The idea that they were suggesting it might 862 00:36:36.130 --> 00:36:38.610 have needed a bit more mass than a single 863 00:36:38.610 --> 00:36:41.570 star to disturb the Oort cloud. And uh, they 864 00:36:41.570 --> 00:36:44.130 suggested the passage nearby, passage of 865 00:36:44.130 --> 00:36:46.610 something called a giant molecular cloud, uh, 866 00:36:46.610 --> 00:36:48.650 a kind of stellar birthplace. If one of those 867 00:36:48.650 --> 00:36:50.850 goes past the solar system, they were 868 00:36:50.850 --> 00:36:53.190 inferring it would disturb the Oort cloud to 869 00:36:53.190 --> 00:36:55.550 the extent that you would get bombardment of 870 00:36:55.550 --> 00:36:57.550 the inner solar system by comets and that 871 00:36:57.550 --> 00:37:00.190 might be visible in the geological record on 872 00:37:00.190 --> 00:37:02.960 Earth. That was basically um, uh, 873 00:37:03.990 --> 00:37:06.510 their principal line of attack. Uh, really 874 00:37:06.510 --> 00:37:09.110 very interesting science. Uh, so this is not 875 00:37:09.110 --> 00:37:11.990 a new idea, but this is new research 876 00:37:12.230 --> 00:37:14.990 that suggests that um, perhaps we can learn 877 00:37:14.990 --> 00:37:16.230 more by pursuing it. 878 00:37:16.790 --> 00:37:19.790 Andrew Dunkley: Indeed, yes. Um, the paper by the way, 879 00:37:19.790 --> 00:37:21.790 has been accepted by the Planetary Science 880 00:37:21.790 --> 00:37:23.500 Journal and is available at the moment, 881 00:37:23.650 --> 00:37:26.290 moment on the Arxiv Preprint server. 882 00:37:26.690 --> 00:37:29.530 You can also read about it at phys.org, p h 883 00:37:29.530 --> 00:37:32.410 y s.org Fred Watson, 884 00:37:32.410 --> 00:37:34.130 that brings us to the end of the show. 885 00:37:34.130 --> 00:37:35.010 Thank you so much. 886 00:37:35.170 --> 00:37:37.330 Professor Fred Watson: Well, that went very quickly. Uh, what a good 887 00:37:37.330 --> 00:37:37.970 time we had. 888 00:37:38.290 --> 00:37:40.450 Andrew Dunkley: We did indeed. Yes. We'll catch you on the 889 00:37:40.450 --> 00:37:40.850 next one. 890 00:37:40.930 --> 00:37:41.650 Professor Fred Watson: Sounds great. 891 00:37:41.890 --> 00:37:43.450 Andrew Dunkley: Thank you very much, Professor Fred Watson 892 00:37:43.450 --> 00:37:45.410 Watson, astronomer at large. And don't forget 893 00:37:45.410 --> 00:37:47.610 between episodes to jump on our website and 894 00:37:47.610 --> 00:37:50.050 have a look around. SpaceNutsPodcast.com you 895 00:37:50.050 --> 00:37:52.290 can click on the AMA button and send us 896 00:37:52.370 --> 00:37:54.410 messages. Even if you want to send us a joke, 897 00:37:54.410 --> 00:37:57.310 we don't mind, we love jokes. Or you can, 898 00:37:57.390 --> 00:37:59.670 uh, send us a question or, um, you can 899 00:37:59.670 --> 00:38:02.670 comment on a discussion point, whatever 900 00:38:02.670 --> 00:38:04.470 you like. Just don't forget to tell us who 901 00:38:04.470 --> 00:38:05.750 you are or where you're from. You can send 902 00:38:05.750 --> 00:38:08.030 text and audio questions and while you're 903 00:38:08.030 --> 00:38:09.390 there, have a look around. Cheque out the 904 00:38:09.390 --> 00:38:12.310 shop. Cheque out. Uh, the, uh, ways 905 00:38:12.310 --> 00:38:14.910 you could become a supporter, uh, or sign up 906 00:38:14.910 --> 00:38:16.790 for the Astronomy AstroDailyPod News feed. 907 00:38:16.790 --> 00:38:19.350 You can do all of that on our website. And 908 00:38:19.350 --> 00:38:21.950 thanks to Huw in the studio who, uh, couldn't 909 00:38:21.950 --> 00:38:23.950 be with us today because he saw a passing 910 00:38:23.950 --> 00:38:26.670 star and chased her down for an autograph. 911 00:38:27.450 --> 00:38:29.890 And from and from me, Andrew Dunkley. Thanks 912 00:38:29.890 --> 00:38:31.410 for your company. We'll see you on the next 913 00:38:31.410 --> 00:38:33.530 episode of Space Nuts. Bye. Bye. 914 00:38:34.730 --> 00:38:36.930 You've been listening to the Space Nuts 915 00:38:36.930 --> 00:38:39.930 podcast, available at 916 00:38:39.930 --> 00:38:41.850 Apple Podcasts, Spotify, 917 00:38:42.090 --> 00:38:44.850 iHeartRadio or your favourite podcast 918 00:38:44.850 --> 00:38:46.570 player. You can also stream on 919 00:38:46.570 --> 00:38:48.850 demand@bytes.com this 920 00:38:48.850 --> 00:38:51.210 Professor Fred Watson: has been another quality podcast production 921 00:38:51.210 --> 00:38:52.730 from bytes.com.