WEBVTT 0 00:00:00.320 --> 00:00:00.760 Professor Fred Watson: Hi there. 1 00:00:00.760 --> 00:00:02.760 Andrew Dunkley: Thanks again for joining us. This is Space 2 00:00:02.760 --> 00:00:05.560 Nuts. My name is Andrew Dunkley and every 3 00:00:05.560 --> 00:00:08.160 week we talk astronomy and space science 4 00:00:08.720 --> 00:00:10.720 and we answer audience questions in our 5 00:00:10.720 --> 00:00:13.280 alternative show, which, uh, happens, 6 00:00:13.460 --> 00:00:16.240 um, well, wherever you are. I mean, we 7 00:00:16.240 --> 00:00:17.960 release it on a Monday, but that doesn't mean 8 00:00:17.960 --> 00:00:20.640 you listen to it on a Monday. Uh, coming up 9 00:00:20.640 --> 00:00:23.040 today we've got, uh, a couple of 10 00:00:23.440 --> 00:00:26.100 nuclear explosive storeys. Uh, 11 00:00:26.100 --> 00:00:28.960 SpaceX is involved in one of those and 12 00:00:29.040 --> 00:00:31.520 the other storey is about, uh, blowing things 13 00:00:31.520 --> 00:00:33.740 up with atomic weapons from space. 14 00:00:34.620 --> 00:00:36.810 Yes, highly guaranteed. Very, very, uh, 15 00:00:36.810 --> 00:00:39.460 effective as well. Uh, but I think there's 16 00:00:39.460 --> 00:00:41.940 probably a reason not to. We'll look at all 17 00:00:41.940 --> 00:00:44.580 of that. Uh, we're also going to talk about 18 00:00:44.580 --> 00:00:47.020 where Earth's, uh, dust came from. Quite a 19 00:00:47.020 --> 00:00:48.780 bit of it, which might come as a bit of a 20 00:00:48.780 --> 00:00:50.620 surprise. Uh, you just have to look under 21 00:00:50.940 --> 00:00:53.100 just about every bed and kitchen table in the 22 00:00:53.100 --> 00:00:55.580 world to find as much dust as there is in the 23 00:00:55.580 --> 00:00:58.180 world. But we'll see where that, uh, is 24 00:00:58.180 --> 00:01:00.940 headed. And our galaxy, uh, reaches 25 00:01:00.940 --> 00:01:03.500 out further than we thought. Apparently, uh, 26 00:01:03.590 --> 00:01:05.230 there's some interesting science behind that. 27 00:01:05.230 --> 00:01:08.030 We'll talk about it all on this edition of 28 00:01:08.030 --> 00:01:08.950 space nuts. 29 00:01:09.030 --> 00:01:11.590 Professor Fred Watson: 15 seconds. Guidance is internal. 30 00:01:11.830 --> 00:01:14.470 10, 9. Ignition 31 00:01:14.470 --> 00:01:15.510 sequence start. 32 00:01:15.670 --> 00:01:16.391 Professor Fred Watson: Space nuts. 33 00:01:16.463 --> 00:01:19.250 Professor Fred Watson: 5, 4, 3, 2. 1, 2, 3, 4, 34 00:01:19.321 --> 00:01:21.430 5, 5, 4, 3, 2, 1. 35 00:01:21.510 --> 00:01:22.710 Andrew Dunkley: Space nuts. 36 00:01:22.710 --> 00:01:24.550 Professor Fred Watson: Astronauts report it feels good. 37 00:01:25.270 --> 00:01:27.710 Andrew Dunkley: And joining us again to talk about all of 38 00:01:27.710 --> 00:01:29.670 that and more is Professor Fred Watson 39 00:01:29.670 --> 00:01:31.510 Watson, astronomer at large. Hello, 40 00:01:31.510 --> 00:01:31.910 Fred Watson. 41 00:01:32.230 --> 00:01:34.670 Professor Fred Watson: Hello, Andrew. Good to see you. Good to see 42 00:01:34.670 --> 00:01:35.770 you. Yes. 43 00:01:35.770 --> 00:01:38.690 We sort of missed a few days, haven't we? 44 00:01:38.690 --> 00:01:39.170 Yes. 45 00:01:40.180 --> 00:01:41.650 Andrew Dunkley: Uh, you've been off conferencing. 46 00:01:41.890 --> 00:01:44.730 Professor Fred Watson: Yes. So the annual science meeting, 47 00:01:44.730 --> 00:01:47.210 as it's called, of the National Astronomy 48 00:01:47.210 --> 00:01:48.890 Society, the Astronomical Society of 49 00:01:48.890 --> 00:01:50.810 Australia, it's where all the professional 50 00:01:50.810 --> 00:01:53.250 astronomers get together and, uh, talk about 51 00:01:53.250 --> 00:01:55.550 what they've been doing, their research. Uh, 52 00:01:55.890 --> 00:01:58.890 it was a big meeting. There were, I would 53 00:01:58.890 --> 00:02:01.170 have guessed, maybe a couple of hundred 54 00:02:01.170 --> 00:02:03.330 people there altogether. Uh, that's quite big 55 00:02:03.330 --> 00:02:05.810 for astronomers in a country that's only got 56 00:02:05.810 --> 00:02:07.430 700 astronomers in it. 57 00:02:07.430 --> 00:02:07.870 Professor Fred Watson: Yeah. 58 00:02:08.020 --> 00:02:10.750 Professor Fred Watson: Uh, but, um, what was interesting and 59 00:02:10.750 --> 00:02:13.070 what was very, I think, 60 00:02:13.310 --> 00:02:15.150 heartening for me was the number of 61 00:02:16.030 --> 00:02:17.990 youngsters that were there. I call them 62 00:02:17.990 --> 00:02:19.470 youngsters, you know, people under 50 63 00:02:20.910 --> 00:02:23.229 people, um, the new generation of 64 00:02:23.229 --> 00:02:26.070 astronomers, uh, most of them whom I didn't 65 00:02:26.070 --> 00:02:28.230 know and they've no idea who I am, and that's 66 00:02:28.230 --> 00:02:31.110 fine. Uh, that all was okay. It 67 00:02:31.110 --> 00:02:33.270 just contrasts with a few years ago. So when 68 00:02:33.270 --> 00:02:35.590 I was the astronomer in charge of the 69 00:02:35.590 --> 00:02:38.300 observatory at, uh, Coonabarabran, uh, 70 00:02:39.050 --> 00:02:41.170 we were kind of the Shopkeepers. So all these 71 00:02:41.170 --> 00:02:43.570 astronomers used to come through, stay in the 72 00:02:43.570 --> 00:02:45.330 lodge and do their research using the 73 00:02:45.330 --> 00:02:48.210 telescope. So I knew a large fraction of 74 00:02:48.210 --> 00:02:50.850 the astronomical population of Australia. But 75 00:02:50.850 --> 00:02:53.530 that's changed, uh, because my job, 76 00:02:53.690 --> 00:02:56.340 that job is no longer mine. Uh, 77 00:02:56.490 --> 00:02:58.970 and so I don't see people the same way. But 78 00:02:59.690 --> 00:03:02.130 it was very nice to meet a lot of new faces 79 00:03:02.130 --> 00:03:04.370 and catch up with some very old faces as 80 00:03:04.370 --> 00:03:07.170 well, some even older than mine. Um, and we 81 00:03:07.170 --> 00:03:10.130 also discussed matters such as the future 82 00:03:10.130 --> 00:03:12.630 of Australian astronomy because that's 83 00:03:12.810 --> 00:03:15.270 uh, in a interesting 84 00:03:15.590 --> 00:03:17.590 state at the moment. With the government 85 00:03:17.750 --> 00:03:20.230 having declined, uh, to 86 00:03:20.870 --> 00:03:23.190 engage in membership with the European 87 00:03:23.190 --> 00:03:25.150 Southern Observatory. We are now working on 88 00:03:25.150 --> 00:03:27.910 plan B. Uh, and um. Well, it looks 89 00:03:27.910 --> 00:03:28.310 promising. 90 00:03:28.550 --> 00:03:31.190 Andrew Dunkley: Yes, fingers crossed. A lot going on. 91 00:03:31.830 --> 00:03:34.750 Okay, um, we should probably get 92 00:03:34.750 --> 00:03:36.550 stuck into these storeys because there's a 93 00:03:36.550 --> 00:03:38.790 lot to discuss. The first storey is a double 94 00:03:38.790 --> 00:03:41.670 banger about nuclear, um, energy and 95 00:03:41.670 --> 00:03:42.630 atomic weapons. 96 00:03:43.320 --> 00:03:45.490 Uh, we'll start off with the storey about 97 00:03:45.570 --> 00:03:47.410 SpaceX. And 98 00:03:48.080 --> 00:03:50.450 um, they're looking at nuclear power 99 00:03:50.690 --> 00:03:53.610 in space, nuclear powered satellites. What's 100 00:03:53.610 --> 00:03:54.530 the storey here? 101 00:03:54.850 --> 00:03:57.730 Professor Fred Watson: It's a test launch, really. A launch of 102 00:03:58.850 --> 00:04:01.480 a cubesat basically that um, 103 00:04:01.490 --> 00:04:03.890 has not a nuclear reactor inside but 104 00:04:04.620 --> 00:04:07.610 um, basically a capsule of something called 105 00:04:07.610 --> 00:04:09.370 tritium which is sometimes called heavy 106 00:04:09.370 --> 00:04:10.930 hydrogen. It's hydrogen with two 107 00:04:11.950 --> 00:04:14.610 electrons in it as well as the proton at uh, 108 00:04:14.750 --> 00:04:17.260 its centre. And it's radioactive. Uh, 109 00:04:17.260 --> 00:04:20.070 tritium is um, I suppose you'd call it 110 00:04:20.070 --> 00:04:22.950 mildly radioactive. Um, we used to 111 00:04:22.950 --> 00:04:25.790 use tritium standard lamps at the 112 00:04:25.790 --> 00:04:28.350 observatory when I was working there, which 113 00:04:28.350 --> 00:04:30.430 was a little capsule of tritium with some 114 00:04:30.430 --> 00:04:32.670 phosphor on it. Um, and 115 00:04:33.650 --> 00:04:36.070 um, basically the electrons released by the 116 00:04:36.070 --> 00:04:38.670 tritium lit up the phosphor and 117 00:04:38.830 --> 00:04:41.390 gave a very constant glow so we could use it 118 00:04:41.390 --> 00:04:43.640 to calibrate other, other instruments. 119 00:04:44.200 --> 00:04:47.070 So I've been close up and personal with um, 120 00:04:47.320 --> 00:04:49.920 a little nuclear power source a bit like 121 00:04:49.920 --> 00:04:51.800 that, but it was just making faint light. 122 00:04:52.200 --> 00:04:54.760 This one is one that's been uh, 123 00:04:54.840 --> 00:04:56.870 developed by a private company. Um, 124 00:04:57.800 --> 00:05:00.640 and it's uh, basically a 125 00:05:00.640 --> 00:05:03.160 company called City Labs, uh, in the United 126 00:05:03.320 --> 00:05:05.240 States. Uh, they've built 127 00:05:05.760 --> 00:05:08.280 um, a little, as I said, it's 128 00:05:08.360 --> 00:05:11.310 effectively a cubesat which has this um, 129 00:05:11.480 --> 00:05:14.320 little nuclear, not nuclear 130 00:05:14.320 --> 00:05:16.400 reactor, but nuclear power source inside a 131 00:05:16.400 --> 00:05:19.280 tritium, uh, source that I've just been 132 00:05:19.280 --> 00:05:21.840 talking about, which doesn't actually convert 133 00:05:21.840 --> 00:05:24.760 the electrons into light, it 134 00:05:24.760 --> 00:05:27.560 converts them directly into electricity. 135 00:05:27.640 --> 00:05:30.440 So they've got these panels on the side of it 136 00:05:30.440 --> 00:05:32.160 that take the electrons that come from the 137 00:05:32.160 --> 00:05:34.680 tritium and turn them straight into 138 00:05:35.140 --> 00:05:38.040 um, electricity. Ah, it's 139 00:05:38.040 --> 00:05:40.960 Called Bohr B O H R, uh, which is 140 00:05:40.960 --> 00:05:43.360 a bit of a play on words because Niels Bohr 141 00:05:43.360 --> 00:05:45.060 was one of the great founders of quantum 142 00:05:45.060 --> 00:05:47.670 theory. Same spelling, um 143 00:05:48.100 --> 00:05:50.590 Danish one, A uh, Danish uh 144 00:05:50.740 --> 00:05:53.060 scientist, uh and it stands for 145 00:05:53.300 --> 00:05:55.980 Beta Voltaic. And a 146 00:05:55.980 --> 00:05:58.860 Beta Voltaic is taking the beta particles, 147 00:05:58.860 --> 00:06:01.410 which are otherwise known as electrons, uh 148 00:06:01.460 --> 00:06:03.700 turning them into electricity. So it's Beta 149 00:06:03.700 --> 00:06:06.260 Voltaic orbital high reliability 150 00:06:06.420 --> 00:06:08.940 spacecraft. That's where you get the Bohr 151 00:06:08.940 --> 00:06:11.710 from and it's been launched. Uh, 152 00:06:11.710 --> 00:06:14.180 so SpaceX's part in this storey is just to 153 00:06:14.180 --> 00:06:17.000 provide the taxi, uh up into um, up 154 00:06:17.000 --> 00:06:18.890 into orbit. It's a transporter, uh 155 00:06:19.640 --> 00:06:22.480 mission, um, basically 156 00:06:22.480 --> 00:06:25.320 one of uh, SpaceX's taxi rides to get stuff 157 00:06:25.320 --> 00:06:28.320 up and down from uh, or up to orbit, 158 00:06:28.480 --> 00:06:30.600 coming down to different storey and most of 159 00:06:30.600 --> 00:06:31.600 them just burn up. 160 00:06:32.080 --> 00:06:32.090 Professor Fred Watson: Yes. 161 00:06:32.090 --> 00:06:34.920 Professor Fred Watson: Uh, but it is uh, probably the 162 00:06:34.920 --> 00:06:37.920 first CubeSat to include a nuclear 163 00:06:37.920 --> 00:06:40.240 power system. Uh and 164 00:06:40.480 --> 00:06:43.410 maybe, just maybe we'll sort of illuminate 165 00:06:43.410 --> 00:06:45.880 the way for a new generation of uh, 166 00:06:46.050 --> 00:06:48.710 spacecraft which are equipped with uh, 167 00:06:48.770 --> 00:06:50.210 these nuclear power sources. 168 00:06:50.450 --> 00:06:53.170 Andrew Dunkley: I suppose they have to look at alternatives 169 00:06:53.170 --> 00:06:55.890 because we've been reliant, fairly 170 00:06:55.890 --> 00:06:58.810 reliant anyway on solar energy in 171 00:06:58.810 --> 00:07:01.570 space, um particularly with our uh, orbiting 172 00:07:01.570 --> 00:07:04.410 satellites, but also with um, the 173 00:07:04.410 --> 00:07:07.000 International Space Station and others. Um, 174 00:07:07.410 --> 00:07:10.210 but the time will come where we are 175 00:07:10.210 --> 00:07:13.040 in places where there won't be that 176 00:07:13.040 --> 00:07:15.880 much sunlight and 177 00:07:16.040 --> 00:07:18.360 in some places there won't be any at all. And 178 00:07:18.840 --> 00:07:20.600 solar panels are going to be useless. 179 00:07:21.200 --> 00:07:23.400 Professor Fred Watson: Uh, that's correct. And we've seen already 180 00:07:23.880 --> 00:07:26.760 um, the use of these UH RTGs, 181 00:07:26.760 --> 00:07:29.160 radioisotope thermoelectric 182 00:07:29.160 --> 00:07:32.040 generators, uh which are carried by both 183 00:07:32.040 --> 00:07:34.770 the Curiosity and the uh 184 00:07:34.840 --> 00:07:37.720 Perseverance rovers, uh as well as 185 00:07:37.720 --> 00:07:40.600 spacecraft in deep space like uh, 186 00:07:40.840 --> 00:07:43.670 Voyager 1, Voyager 2, Pioneers. I think 187 00:07:43.670 --> 00:07:45.510 they've got them as well. And these are 188 00:07:45.510 --> 00:07:47.430 spacecraft that are so far from the sun that 189 00:07:47.430 --> 00:07:49.950 you get very little light from the sun, 190 00:07:50.380 --> 00:07:52.390 uh in terms of um, you know, using it to 191 00:07:52.390 --> 00:07:54.710 generate electricity. So they've, they've had 192 00:07:54.710 --> 00:07:56.910 their nuclear power sources for a long time. 193 00:07:57.070 --> 00:07:58.670 They are quite different though from what 194 00:07:58.670 --> 00:08:00.630 we're talking about here. There are, I think 195 00:08:00.630 --> 00:08:02.950 it's 13 kilogrammes if I remember rightly, is 196 00:08:02.950 --> 00:08:05.230 the amount in a canister of plutonium 197 00:08:05.470 --> 00:08:07.990 dioxide, uh which is 198 00:08:07.990 --> 00:08:10.870 decaying all the time and getting very hot as 199 00:08:10.870 --> 00:08:13.540 it does that and that heat is then used 200 00:08:13.770 --> 00:08:16.570 to generate electricity, uh and 201 00:08:17.210 --> 00:08:19.970 it actually dies away as time goes on. So 202 00:08:19.970 --> 00:08:22.610 these nuclear uh, RTGs, the 203 00:08:22.610 --> 00:08:24.650 radioisotope thermoelectric generators 204 00:08:25.290 --> 00:08:28.050 gradually lose their power, um, and that's 205 00:08:28.050 --> 00:08:30.930 why we hear from time to time and we usually 206 00:08:30.930 --> 00:08:33.850 report this on space nuts. We hear of 207 00:08:33.890 --> 00:08:36.730 uh, uh instruments on board Voyager 1 208 00:08:36.730 --> 00:08:39.210 being turned off to save the power. 209 00:08:39.890 --> 00:08:42.490 Andrew Dunkley: Yeah. And that happened again not so long 210 00:08:42.490 --> 00:08:42.690 ago. 211 00:08:42.690 --> 00:08:45.490 Professor Fred Watson: I think that's correct. Yes it did. 212 00:08:45.570 --> 00:08:47.490 There was one turned off uh quite recently 213 00:08:47.810 --> 00:08:49.730 but perhaps more to the point and 214 00:08:50.640 --> 00:08:52.370 uh, what you've just said about there being 215 00:08:52.370 --> 00:08:54.530 some places that have no sunlight whatsoever, 216 00:08:54.900 --> 00:08:57.730 uh that applies to uh, those deep 217 00:08:57.730 --> 00:09:00.610 craters near the moon's south pole 218 00:09:00.930 --> 00:09:03.410 and that's where we're thinking of exploring. 219 00:09:03.810 --> 00:09:06.370 So it may be that um, these 220 00:09:06.690 --> 00:09:08.880 beta voltaic arrays 221 00:09:09.440 --> 00:09:12.320 uh uh, or devices might well 222 00:09:12.560 --> 00:09:14.960 be the future of power generation 223 00:09:15.680 --> 00:09:17.760 near the moon's south pole because you're in 224 00:09:17.760 --> 00:09:20.120 places where there's no light whatsoever from 225 00:09:20.120 --> 00:09:20.560 the sun. 226 00:09:20.640 --> 00:09:23.360 Andrew Dunkley: That's absolutely true. Darn cold too. It is. 227 00:09:23.680 --> 00:09:26.400 Professor Fred Watson: It is always cold there. Yes, yes 228 00:09:26.640 --> 00:09:27.200 indeed. 229 00:09:27.340 --> 00:09:29.840 Andrew Dunkley: Uh, uh that's a really interesting storey and 230 00:09:30.160 --> 00:09:32.480 we're obviously in the early phases of 231 00:09:32.480 --> 00:09:34.880 finding these alternatives. Is um, tritium 232 00:09:35.240 --> 00:09:35.640 safe? 233 00:09:36.520 --> 00:09:39.400 Professor Fred Watson: Uh, it's probably something regarded 234 00:09:39.760 --> 00:09:41.880 uh, treated carefully. 235 00:09:43.480 --> 00:09:46.160 It is generally safe. I mean we never took 236 00:09:46.160 --> 00:09:48.360 any real precautions with the device that we 237 00:09:48.360 --> 00:09:51.320 had on the telescope. Maybe we should 238 00:09:51.320 --> 00:09:54.280 have done. Although uh, most of 239 00:09:54.280 --> 00:09:56.960 us are still around and in fairly good 240 00:09:56.960 --> 00:09:59.320 health. But um, yes they are 241 00:09:59.640 --> 00:10:02.280 releasing electrons, uh beta radiation, 242 00:10:02.740 --> 00:10:05.670 uh, it's um, uh if you had a 243 00:10:05.750 --> 00:10:07.910 high level though of tritium, if you had a 244 00:10:08.310 --> 00:10:10.070 significant amount of it then you would have 245 00:10:10.070 --> 00:10:12.230 to be careful about how you handled it and 246 00:10:12.310 --> 00:10:14.230 where it was put and if it needed shielding 247 00:10:14.230 --> 00:10:15.270 and things of that sort. 248 00:10:15.430 --> 00:10:17.190 Andrew Dunkley: Yeah. So uh, don't sprinkle it on your 249 00:10:17.190 --> 00:10:18.950 cornflakes or anything like that. 250 00:10:18.950 --> 00:10:20.870 Professor Fred Watson: Yes, that's right. It's best to avoid it if 251 00:10:20.870 --> 00:10:21.190 you can. 252 00:10:21.190 --> 00:10:24.150 Andrew Dunkley: Yeah. Sugar's damaging enough already. 253 00:10:25.110 --> 00:10:27.590 Professor Fred Watson: It is. Tell my dentist about it. 254 00:10:27.750 --> 00:10:30.230 Andrew Dunkley: If you'd like to um, read up on that storey 255 00:10:30.230 --> 00:10:32.510 about the uh, the launch of the cubesat with 256 00:10:32.510 --> 00:10:35.270 the tritium nuclear ah power device 257 00:10:35.730 --> 00:10:37.170 they're testing. Uh you can read about 258 00:10:37.170 --> 00:10:40.050 it@dailygalaxy.com. 259 00:10:41.280 --> 00:10:43.890 um, let's keep on this theme 260 00:10:43.890 --> 00:10:45.490 Fred Watson, because that's the good news. 261 00:10:45.680 --> 00:10:47.900 Uh the bad news is um, 262 00:10:49.170 --> 00:10:51.890 the the problem of exploding nuclear 263 00:10:51.890 --> 00:10:54.730 devices in space or firing nuclear 264 00:10:54.730 --> 00:10:56.930 devices from space to targets on Earth. 265 00:10:56.930 --> 00:10:59.490 That's, that's a real issue. I know. 266 00:10:59.630 --> 00:11:02.370 Um, was it back in the 80s the 267 00:11:02.370 --> 00:11:04.380 Star wars um 268 00:11:05.650 --> 00:11:08.610 um push was uh, all the rage in the news 269 00:11:08.610 --> 00:11:10.730 at the time and uh, that got shut down pretty 270 00:11:10.730 --> 00:11:11.130 quickly. 271 00:11:12.090 --> 00:11:14.810 Professor Fred Watson: Star wars was um, a 272 00:11:14.810 --> 00:11:17.650 Reagan era initiative. Yes, I think it was, I 273 00:11:17.650 --> 00:11:20.170 think it was um, uh basically 274 00:11:20.170 --> 00:11:22.490 electromagnetic Radiation to zap your 275 00:11:22.490 --> 00:11:24.460 satellites. It wasn't nuclear though, uh, 276 00:11:24.490 --> 00:11:27.370 because nuclear weapons are in space, are 277 00:11:27.370 --> 00:11:30.010 prohibited by the outer Space Treaty 278 00:11:30.410 --> 00:11:31.290 1967. 279 00:11:31.610 --> 00:11:32.650 Andrew Dunkley: So what's happening? 280 00:11:32.810 --> 00:11:34.730 Professor Fred Watson: They're not allowed. But, 281 00:11:35.810 --> 00:11:37.770 um, there may be some there 282 00:11:38.490 --> 00:11:41.050 launched by powers that 283 00:11:42.490 --> 00:11:44.290 stretch um, the envelope, if I can put it 284 00:11:44.290 --> 00:11:46.690 that way. Governments that stretch the 285 00:11:46.690 --> 00:11:49.530 envelope. And uh, we don't know. We don't 286 00:11:49.530 --> 00:11:51.650 know if there are any. You know, they're 287 00:11:51.650 --> 00:11:54.490 banned by the uh, Outer Space Treaty. So 288 00:11:54.490 --> 00:11:57.050 there shouldn't be any nuclear weapons in 289 00:11:57.050 --> 00:12:00.030 space. But that's all very well. 290 00:12:00.070 --> 00:12:00.110 Professor Fred Watson: Um. 291 00:12:01.070 --> 00:12:02.830 Professor Fred Watson: There's a lot of things that shouldn't happen 292 00:12:03.070 --> 00:12:05.910 but do happen. And um. So it may be 293 00:12:05.910 --> 00:12:07.830 that perhaps there are nuclear weapons in 294 00:12:07.830 --> 00:12:10.350 space. So the question is, 295 00:12:11.350 --> 00:12:13.890 um, how do you detect them if there are, 296 00:12:13.890 --> 00:12:16.560 ah, these weapons? Um, 297 00:12:16.910 --> 00:12:19.630 and um, that's 298 00:12:20.110 --> 00:12:23.110 where this piece of research, uh, from 299 00:12:23.110 --> 00:12:25.470 the Massachusetts Institute of Technology 300 00:12:26.190 --> 00:12:29.030 has come from. It's um, a um, person 301 00:12:29.030 --> 00:12:31.790 whose name is Areg Dana 302 00:12:31.790 --> 00:12:34.670 Gulian. Sounds uh, like an Armenian name. 303 00:12:34.670 --> 00:12:37.430 Does that usually I a n on the end. Armenian. 304 00:12:37.590 --> 00:12:39.870 An associate professor of nuclear science and 305 00:12:39.870 --> 00:12:42.430 engineering at the Massachusetts Institute of 306 00:12:42.430 --> 00:12:44.870 Technology. And he has 307 00:12:45.220 --> 00:12:47.030 um, essentially 308 00:12:47.910 --> 00:12:49.830 thought of a neat way, 309 00:12:52.140 --> 00:12:55.110 uh, of building a device that 310 00:12:55.350 --> 00:12:58.230 you could fly in the vicinity 311 00:12:58.630 --> 00:13:01.510 of a satellite to detect whether 312 00:13:01.670 --> 00:13:03.750 it is carrying nuclear weapons. 313 00:13:04.640 --> 00:13:07.190 Um, and it's all about the subatomic 314 00:13:07.190 --> 00:13:10.190 particles, uh, that um, you know, 315 00:13:10.190 --> 00:13:12.980 that, that nuclear um, 316 00:13:13.310 --> 00:13:16.250 weapons are all about. It's all about uh, 317 00:13:16.250 --> 00:13:18.630 neutrons and uh, you know, the nuclear 318 00:13:18.710 --> 00:13:20.830 nuclei of atoms. That's where it all comes 319 00:13:20.830 --> 00:13:23.040 from. Um, so 320 00:13:25.440 --> 00:13:27.840 what he has suggested, and I might 321 00:13:27.840 --> 00:13:29.640 quote, um, 322 00:13:30.960 --> 00:13:33.760 I might quote from uh, Dr. Dana 323 00:13:33.760 --> 00:13:35.760 Gulian's work. Uh 324 00:13:36.800 --> 00:13:39.680 the risk is that 325 00:13:39.680 --> 00:13:42.600 if you did explode a nuclear weapon in 326 00:13:42.600 --> 00:13:45.520 low Earth orbit, then you basically wreck low 327 00:13:45.520 --> 00:13:47.600 Earth orbit for everybody. It's not the 328 00:13:47.600 --> 00:13:50.600 blast, it's just the subatomic particles that 329 00:13:50.600 --> 00:13:53.500 do it. Uh, and so what he goes on to say 330 00:13:53.500 --> 00:13:56.500 is this danger is compounded by the lack 331 00:13:56.500 --> 00:13:58.740 of a verification mechanism for the Outer 332 00:13:58.740 --> 00:14:00.710 Space Treaty. Um, 333 00:14:01.820 --> 00:14:04.340 there's no detection methodologies that have 334 00:14:04.340 --> 00:14:06.620 been proposed in the scientific literature. 335 00:14:06.700 --> 00:14:09.139 So what he's saying is here's a concept and 336 00:14:09.139 --> 00:14:11.660 feasibility study, um, for 337 00:14:11.660 --> 00:14:14.220 verifying a satellite's compliance 338 00:14:14.540 --> 00:14:17.100 to the Outer Space Treaty by observing 339 00:14:17.420 --> 00:14:20.220 the neutrons induced by spallation 340 00:14:20.300 --> 00:14:21.660 from the approximately 341 00:14:23.660 --> 00:14:26.080 giga electron volt protons in the 342 00:14:26.080 --> 00:14:28.840 Innovant Allen radiation belts, which is 343 00:14:28.840 --> 00:14:31.440 a slightly complicated and technical way of 344 00:14:31.440 --> 00:14:34.040 saying, uh, you've already got subatomic 345 00:14:34.040 --> 00:14:36.920 particles in the radiation belts around 346 00:14:37.480 --> 00:14:40.040 our planet. Um, if you can, 347 00:14:41.650 --> 00:14:44.200 um, basically watch the way, 348 00:14:44.790 --> 00:14:47.720 um, a satellite responds 349 00:14:47.720 --> 00:14:50.560 to those protons that are in the radiation 350 00:14:50.560 --> 00:14:53.260 belts. Um, if for example that uh, 351 00:14:53.400 --> 00:14:55.320 bombardment of protons from the radiation 352 00:14:55.320 --> 00:14:57.700 belts causes neutron neutrons to be 353 00:14:58.110 --> 00:15:00.660 uh, emitted then you can 354 00:15:01.140 --> 00:15:02.660 have a fair degree of 355 00:15:04.250 --> 00:15:06.220 um, confidence that there might be a nuclear 356 00:15:06.220 --> 00:15:08.900 weapon on board or a lot of nuclear fissile 357 00:15:08.900 --> 00:15:11.540 material, heavy elements like uranium. 358 00:15:11.780 --> 00:15:14.100 That's the kind of thing that this is all 359 00:15:14.100 --> 00:15:16.980 about. And so um, 360 00:15:18.210 --> 00:15:21.180 uh, what this is all 361 00:15:21.180 --> 00:15:23.660 about is building uh, a 362 00:15:23.660 --> 00:15:25.860 satellite that can detect 363 00:15:26.750 --> 00:15:29.660 uh, neutrons uh, coming 364 00:15:29.660 --> 00:15:32.660 from radioactive material. And 365 00:15:33.060 --> 00:15:35.900 he's basically suggesting a 366 00:15:35.900 --> 00:15:38.620 detector, uh, uh, uh, what 367 00:15:38.620 --> 00:15:41.500 he calls an inspector satellite that flies 368 00:15:41.500 --> 00:15:44.460 by, uh, the satellite that you're 369 00:15:44.460 --> 00:15:46.140 interested in finding out whether it's got 370 00:15:46.140 --> 00:15:48.980 nuclear weapons. And it's got these detectors 371 00:15:49.210 --> 00:15:51.420 uh, which are almost like X ray detectors. 372 00:15:51.420 --> 00:15:54.380 The kind of things that you see now when you 373 00:15:54.380 --> 00:15:56.180 go for an X ray, a chest X ray. They're 374 00:15:56.180 --> 00:15:58.360 electronic, they're not photograph they used 375 00:15:58.360 --> 00:16:01.240 to be back in the day. Um, and they've got 376 00:16:01.240 --> 00:16:03.560 what are called neutron sensors, uh they're 377 00:16:03.560 --> 00:16:06.560 called scintillators. And uh, you 378 00:16:06.560 --> 00:16:09.360 put those in a special arrangement with 379 00:16:09.440 --> 00:16:11.760 other basically other detectors. 380 00:16:12.320 --> 00:16:15.280 Uh, and um, if you do that then 381 00:16:15.840 --> 00:16:18.680 you can apparently sort out the 382 00:16:18.680 --> 00:16:20.960 neutrons from the other natural 383 00:16:21.200 --> 00:16:23.440 subatomic particles that are floating around 384 00:16:23.760 --> 00:16:26.320 near the radiation belts. And the neutrons 385 00:16:26.320 --> 00:16:28.840 come from radioactive material and you can 386 00:16:28.840 --> 00:16:30.500 also see the direct direction that they're 387 00:16:30.500 --> 00:16:33.140 coming from. So you can sort of point this 388 00:16:33.140 --> 00:16:35.820 thing towards your target satellite, uh, the 389 00:16:35.820 --> 00:16:37.380 one that you suspect might have nuclear 390 00:16:37.380 --> 00:16:39.940 weapons and it will give you the direction of 391 00:16:39.940 --> 00:16:42.540 where it's coming from. Um, and 392 00:16:42.780 --> 00:16:45.020 so uh, just a quote, 393 00:16:45.560 --> 00:16:48.140 um again from Dr. Dana 394 00:16:48.140 --> 00:16:51.100 Gulian. Um, the calculations show 395 00:16:51.260 --> 00:16:54.060 that a nine unit cubesat size 396 00:16:54.060 --> 00:16:56.340 detection platform, that's something the size 397 00:16:56.340 --> 00:16:58.500 of, what's that, about three loaves of bread? 398 00:16:58.500 --> 00:17:00.420 Something of that sort size. It's quite 399 00:17:00.420 --> 00:17:03.370 small. Um, it can identify a 400 00:17:03.370 --> 00:17:06.210 thermonuclear weapon from a distance of 401 00:17:06.210 --> 00:17:09.090 four kilometres in approximately one 402 00:17:09.090 --> 00:17:12.050 week of observation. Now that's quite a long 403 00:17:12.050 --> 00:17:15.010 time but uh, apparently 404 00:17:15.010 --> 00:17:17.490 if you could get it to within one kilometre 405 00:17:17.970 --> 00:17:20.650 it would take you about an hour to detect a 406 00:17:20.650 --> 00:17:22.690 weapon. And that's 407 00:17:23.490 --> 00:17:26.290 promising. That's one flyby, that's you know, 408 00:17:26.450 --> 00:17:29.330 an hour of proximity, uh, you could do that 409 00:17:29.330 --> 00:17:32.170 as you go past the 410 00:17:32.170 --> 00:17:35.070 suspect satell. If you got an hour in 411 00:17:35.230 --> 00:17:37.730 close uh, contact with it or close uh, 412 00:17:38.030 --> 00:17:40.390 proximity to it within a 413 00:17:40.390 --> 00:17:43.150 kilometre, uh, then you might well 414 00:17:43.630 --> 00:17:45.750 detect a nuclear weapon on board. And of 415 00:17:45.750 --> 00:17:47.350 course you could improve that if you had more 416 00:17:47.350 --> 00:17:49.950 than one of these inspector satellites. If 417 00:17:49.950 --> 00:17:51.790 you multiplied them up, then you could get, 418 00:17:51.870 --> 00:17:53.990 uh, quite significant improvements in that 419 00:17:53.990 --> 00:17:56.030 performance. So it's really quite 420 00:17:56.030 --> 00:17:58.430 interesting. Um, uh, one 421 00:17:58.830 --> 00:18:01.620 quote that I really liked, um, 422 00:18:02.060 --> 00:18:04.890 and I'm going to read, uh, 423 00:18:04.890 --> 00:18:07.220 from, uh. Universe Today has a very nice 424 00:18:07.220 --> 00:18:09.380 article on this. The last sentence is, right 425 00:18:09.380 --> 00:18:12.300 now, nations like the USA and Russia rely on 426 00:18:12.300 --> 00:18:14.540 intelligence to know what the other is doing. 427 00:18:14.860 --> 00:18:17.300 And as we know from history, intelligence can 428 00:18:17.300 --> 00:18:20.260 get things wrong. You can fake intelligence, 429 00:18:20.260 --> 00:18:23.020 said Dr. Dana Gulian, but you can't fake 430 00:18:23.020 --> 00:18:25.820 physics. I like that. Yeah, it's true. So 431 00:18:26.060 --> 00:18:27.910 you could do it by physics. Yeah. 432 00:18:28.150 --> 00:18:31.110 Andrew Dunkley: They do, uh, mention in this particular 433 00:18:31.190 --> 00:18:33.590 article that there's one suspect satellite 434 00:18:33.590 --> 00:18:35.750 that seems to have been launched by Russia. 435 00:18:35.990 --> 00:18:38.990 And the bottom line is that it's 436 00:18:38.990 --> 00:18:41.670 been put in an orbit that is very strange 437 00:18:42.550 --> 00:18:45.230 and very hostile in terms 438 00:18:45.230 --> 00:18:47.910 of its radiation, uh, in that area. 439 00:18:47.910 --> 00:18:50.830 And the question is asked. Well, it says no 440 00:18:50.830 --> 00:18:52.750 one puts satellites there because it's highly 441 00:18:52.750 --> 00:18:55.550 radioactive. Why would you put a satellite in 442 00:18:55.550 --> 00:18:58.070 that orbit? So that's one they've already. 443 00:18:58.670 --> 00:19:01.110 They haven't identified as maybe carrying a 444 00:19:01.110 --> 00:19:02.910 nuclear weapon, but they've certainly 445 00:19:03.230 --> 00:19:04.990 identified it as suspicious. 446 00:19:05.310 --> 00:19:08.090 Professor Fred Watson: Yes, that's correct. And so, um. 447 00:19:08.090 --> 00:19:10.150 Yes, highlighting that, I think, you know, 448 00:19:10.150 --> 00:19:12.950 puts this article in context. It 449 00:19:12.950 --> 00:19:14.810 tells you that this is a real issue and, um, 450 00:19:14.910 --> 00:19:17.070 we kind of need to work on how you might 451 00:19:17.070 --> 00:19:19.150 detect, uh, nuclear weapons in space. 452 00:19:19.870 --> 00:19:22.150 Andrew Dunkley: Of course, the other side of it is if you do 453 00:19:22.150 --> 00:19:24.150 identify a satellite that's carrying a 454 00:19:24.150 --> 00:19:26.770 nuclear weapon, what do you do next? 455 00:19:27.410 --> 00:19:29.130 It's like trying to teach people not to 456 00:19:29.130 --> 00:19:31.010 overtake emerging lanes, isn't it? 457 00:19:31.660 --> 00:19:34.610 Professor Fred Watson: Uh, yes. Uh, but, 458 00:19:34.780 --> 00:19:37.090 uh, it's worse than that really, because. A 459 00:19:37.090 --> 00:19:39.610 little bit, yeah, you know, we have 460 00:19:39.610 --> 00:19:41.930 nations that completely disregard 461 00:19:41.930 --> 00:19:44.330 international law. They invade other 462 00:19:44.330 --> 00:19:47.250 countries without so much as a, 463 00:19:47.810 --> 00:19:49.970 you know, a sniff of the, 464 00:19:50.580 --> 00:19:53.370 um, um. Of the, um. 465 00:19:53.570 --> 00:19:55.310 All the international treaties, they just, 466 00:19:55.380 --> 00:19:57.700 Just run amok among them and away they go. 467 00:19:58.220 --> 00:20:01.060 Uh, and yes, so that's the possibility that, 468 00:20:01.060 --> 00:20:02.340 uh, we might already have them. 469 00:20:02.820 --> 00:20:04.660 There is a kind of 470 00:20:05.700 --> 00:20:07.780 corollary of this which I was thinking of 471 00:20:07.780 --> 00:20:10.700 when I read this, Storey. Um, and 472 00:20:10.700 --> 00:20:12.820 that is that back in the 70s, 473 00:20:13.580 --> 00:20:15.540 uh, gamma ray 474 00:20:16.180 --> 00:20:18.260 satellites were launched, 475 00:20:18.660 --> 00:20:21.100 satellites that detect gamma radiation. And 476 00:20:21.100 --> 00:20:23.900 that was to detect any in 477 00:20:23.900 --> 00:20:26.900 atmosphere nuclear tests, uh, conducted on, 478 00:20:27.680 --> 00:20:29.640 uh. Because there was a test ban treaty that 479 00:20:29.640 --> 00:20:32.600 was signed, uh, all the signatories 480 00:20:32.600 --> 00:20:34.920 said, no, we won't test nuclear, uh, weapons 481 00:20:34.920 --> 00:20:37.560 in the atmosphere. Uh, but they had to 482 00:20:37.560 --> 00:20:40.000 verify it. And so the verification process 483 00:20:40.080 --> 00:20:42.480 involved, uh, a number of satellites being 484 00:20:42.480 --> 00:20:44.280 launched that could detect gamma rays which 485 00:20:44.280 --> 00:20:46.880 would be emitted by a nuclear bomb being 486 00:20:46.880 --> 00:20:49.200 detonated in the atmosphere. Uh, 487 00:20:49.600 --> 00:20:52.320 now none were. But those 488 00:20:52.320 --> 00:20:54.520 satellites are what detected gamma ray 489 00:20:54.520 --> 00:20:57.000 bursts. These um, you know, fascinating 490 00:20:57.000 --> 00:21:00.000 pulses of radiation that come from, uh, from 491 00:21:00.000 --> 00:21:02.800 explosions deep in space. Yeah, of course, 492 00:21:03.200 --> 00:21:05.960 man made explosions, but natural ones. Yes. 493 00:21:05.960 --> 00:21:08.480 Andrew Dunkley: Because if they do start detecting nuclear, 494 00:21:08.890 --> 00:21:11.600 uh, weapons in space, then the 495 00:21:11.600 --> 00:21:14.040 parties involved, uh, they won't say, oh, 496 00:21:14.040 --> 00:21:15.520 sorry, sorry, we'll take them all down. 497 00:21:16.000 --> 00:21:17.520 They'll find ways of hiding them. 498 00:21:18.320 --> 00:21:20.160 Professor Fred Watson: Probably. Yes, that's probably right. 499 00:21:21.200 --> 00:21:22.740 Andrew Dunkley: Gosh, it's tough, isn't it? 500 00:21:23.490 --> 00:21:24.810 Professor Fred Watson: Uh, tough world we live in. 501 00:21:24.890 --> 00:21:27.770 Andrew Dunkley: Indeed. Uh, and beyond it in some 502 00:21:27.770 --> 00:21:29.690 respects. Uh, you can read that 503 00:21:29.690 --> 00:21:32.610 storey@universetoday.com. this 504 00:21:32.610 --> 00:21:34.650 is space Nuts with Andrew Dunkley and 505 00:21:34.650 --> 00:21:35.930 Professor Fred Watson Watson. 506 00:21:40.410 --> 00:21:41.530 Space Nuts. 507 00:21:42.480 --> 00:21:45.290 Uh, next storey, Fred Watson, uh, is 508 00:21:45.290 --> 00:21:48.290 looking at, uh, all the dust on Earth 509 00:21:48.290 --> 00:21:50.850 and where it might have come from. Now I was 510 00:21:50.850 --> 00:21:52.610 thinking cats because 511 00:21:53.650 --> 00:21:56.570 they do shed. Uh, but it's uh, a bit 512 00:21:56.570 --> 00:21:59.330 more involved than that. And what 513 00:21:59.330 --> 00:22:01.650 is really interesting about this storey is 514 00:22:01.730 --> 00:22:04.130 they think a heck of a lot of it came from 515 00:22:04.130 --> 00:22:05.010 one source. 516 00:22:07.010 --> 00:22:09.410 Professor Fred Watson: That's right. And it's a mysterious one as 517 00:22:09.410 --> 00:22:11.730 well. Um, so this is 518 00:22:12.130 --> 00:22:14.820 quite a nice storey, uh, from publishing, uh, 519 00:22:15.290 --> 00:22:18.260 Science Adventures. Um, it's 520 00:22:18.420 --> 00:22:20.420 about, uh, the 521 00:22:20.900 --> 00:22:23.620 micrometeorites that bombard the Earth. 522 00:22:24.340 --> 00:22:27.180 And it's a bit surprising, this 523 00:22:27.180 --> 00:22:29.780 stuff. Uh, you know, we think of meteorites 524 00:22:29.780 --> 00:22:32.020 as big chunks of rock that come through the 525 00:22:32.020 --> 00:22:34.780 atmosphere, they have a blaze of glory and 526 00:22:34.780 --> 00:22:36.820 then land on the Earth somewhere. And 527 00:22:38.260 --> 00:22:41.100 what we've got there is um, a 528 00:22:41.100 --> 00:22:43.980 free sample of extraterrestrial 529 00:22:43.980 --> 00:22:46.340 material. But there are also these 530 00:22:46.340 --> 00:22:48.900 micrometeorites which rain on the Earth's 531 00:22:48.900 --> 00:22:50.960 atmosphere and they're dust particles, as 532 00:22:50.960 --> 00:22:52.690 you've kind of hinted. Uh, 533 00:22:53.820 --> 00:22:56.520 um, and they're sort of always 534 00:22:56.520 --> 00:22:59.280 falling on Earth. Uh, and that, 535 00:22:59.860 --> 00:23:02.720 uh, is again, it's a free gift from space. 536 00:23:03.500 --> 00:23:05.760 Um, I think. So I was sort of 537 00:23:06.320 --> 00:23:09.160 vaguely involved with this stuff probably 50 538 00:23:09.160 --> 00:23:12.120 years ago, back in the 70s. I think they 539 00:23:12.120 --> 00:23:14.670 were then called Brownlee particles. Um. 540 00:23:14.880 --> 00:23:16.400 Oh, that sounds familiar. We're talking 541 00:23:16.400 --> 00:23:19.200 about. Yeah. Uh, but they're now, 542 00:23:19.440 --> 00:23:21.760 I think, called cosmic spherules. Uh, I 543 00:23:21.760 --> 00:23:23.760 should cheque whether Brownlee particles and 544 00:23:24.000 --> 00:23:26.920 cosmic spherules are the same thing, but 545 00:23:26.920 --> 00:23:29.920 basically what they are 546 00:23:29.920 --> 00:23:32.880 is bits of meteor that have 547 00:23:33.040 --> 00:23:35.880 melted as they come down through the 548 00:23:35.880 --> 00:23:36.960 Earth's atmosphere, but 549 00:23:38.640 --> 00:23:40.760 they actually survive into the inner 550 00:23:40.760 --> 00:23:43.080 atmosphere and they cool down and they form a 551 00:23:43.080 --> 00:23:46.060 little sphere because the um, basically the 552 00:23:46.060 --> 00:23:48.380 surface tension of molten material brings 553 00:23:48.380 --> 00:23:51.340 them into a sphere. Uh, and that 554 00:23:51.740 --> 00:23:54.540 uh, is the storey so far 555 00:23:54.540 --> 00:23:57.100 because that um, heating 556 00:23:57.340 --> 00:24:00.060 that you, that they experience as 557 00:24:00.060 --> 00:24:03.020 the sort of parent Body, the meteor. Meteor 558 00:24:03.020 --> 00:24:04.820 or meteorite, as it comes through the 559 00:24:04.820 --> 00:24:07.410 atmosphere, it, um, 560 00:24:07.580 --> 00:24:09.580 kind of destroys their chemical 561 00:24:10.140 --> 00:24:12.340 structure, you know, the minerals in it. It 562 00:24:12.980 --> 00:24:15.300 get metamorphosed, they get changed because 563 00:24:15.300 --> 00:24:16.700 they've been subject to very high 564 00:24:16.700 --> 00:24:19.580 temperatures. Um, but there is 565 00:24:19.580 --> 00:24:22.180 a technique, uh, that allows you 566 00:24:22.340 --> 00:24:25.340 to look at, uh, some 567 00:24:25.340 --> 00:24:27.660 of the characteristics of these 568 00:24:27.660 --> 00:24:30.580 objects that is not destroyed by 569 00:24:30.740 --> 00:24:33.380 heat. And it's the oxygen 570 00:24:33.780 --> 00:24:36.740 isotope signature, uh, which we've 571 00:24:36.740 --> 00:24:38.020 talked about before. We've talked about 572 00:24:38.020 --> 00:24:40.820 isotopes and how they, uh, you know, how we 573 00:24:40.820 --> 00:24:42.780 distinguish between heavy water and normal 574 00:24:42.780 --> 00:24:44.480 water and all of that sort, sort of thing. 575 00:24:45.200 --> 00:24:47.970 That's. So it's basically the. The number of, 576 00:24:47.970 --> 00:24:50.680 uh, neutrons in an atom. Um, 577 00:24:51.280 --> 00:24:53.440 so you've got these oxygen 578 00:24:53.440 --> 00:24:55.600 signatures, uh, that, 579 00:24:56.930 --> 00:24:58.960 um, essentially, uh, let you, 580 00:24:59.950 --> 00:25:02.520 ah, group these cosmic 581 00:25:02.520 --> 00:25:05.160 spherules, the Brownlee particles, if that's 582 00:25:05.160 --> 00:25:07.840 what they are. Um, and it turns out 583 00:25:08.000 --> 00:25:10.760 that so, so people do, you know, they do 584 00:25:10.760 --> 00:25:13.640 population census statistics on these objects 585 00:25:13.640 --> 00:25:16.360 to find out, uh, what 586 00:25:16.360 --> 00:25:18.280 relationships they bear with one another. 587 00:25:19.560 --> 00:25:22.400 About 10% of them of these 588 00:25:22.400 --> 00:25:24.880 ferals that have been identified and 589 00:25:24.880 --> 00:25:27.800 analysed collect in a group 590 00:25:27.960 --> 00:25:30.760 that has got the wonderful name of Group 591 00:25:30.760 --> 00:25:33.560 four, uh, which presumably means 592 00:25:33.560 --> 00:25:36.230 there's another three as well. Yeah. Um, 593 00:25:36.250 --> 00:25:39.130 and it's, uh, the. Again, what 594 00:25:39.690 --> 00:25:42.570 makes them stand out in this group is the 595 00:25:42.970 --> 00:25:45.650 oxygen isotope signature that I just 596 00:25:45.650 --> 00:25:48.290 mentioned before. It's depleted in, uh, an 597 00:25:48.290 --> 00:25:50.250 isotope called oxygen 16. 598 00:25:51.210 --> 00:25:54.010 But here's where the storey gets very 599 00:25:54.010 --> 00:25:56.450 interesting because, um, 600 00:25:57.610 --> 00:26:00.330 no known meteorites have 601 00:26:00.330 --> 00:26:03.210 that same oxygen isotope signature. 602 00:26:03.690 --> 00:26:06.580 And you'd expect, uh, if these 603 00:26:06.580 --> 00:26:09.460 things were common, that there would be 604 00:26:09.700 --> 00:26:12.420 meteorites, uh, that match them in their 605 00:26:12.420 --> 00:26:15.220 composition. Uh, and often with 606 00:26:15.220 --> 00:26:17.020 meteorites we can get an idea where they've 607 00:26:17.020 --> 00:26:19.260 come from. Uh, most of them come from the 608 00:26:19.260 --> 00:26:21.300 asteroid belt from collisions between 609 00:26:21.300 --> 00:26:23.980 asteroids. Uh, so, uh, 610 00:26:24.560 --> 00:26:27.500 um, that is a bit mysterious 611 00:26:27.500 --> 00:26:30.420 that we've got these subatomic, sorry, these 612 00:26:31.710 --> 00:26:34.150 small spherules of material that have come 613 00:26:34.150 --> 00:26:36.670 down through the atmosphere, uh, and got that 614 00:26:36.910 --> 00:26:39.790 globular shape. Um, it's 615 00:26:40.110 --> 00:26:42.670 mysterious that we don't know. We don't see 616 00:26:42.670 --> 00:26:45.350 any meteorites that match their 617 00:26:45.350 --> 00:26:46.030 composition. 618 00:26:46.589 --> 00:26:47.069 Andrew Dunkley: Weird. 619 00:26:47.550 --> 00:26:50.510 Professor Fred Watson: It is weird, yes. Uh, and so what 620 00:26:50.510 --> 00:26:53.160 they're suggesting is that, um, 621 00:26:53.160 --> 00:26:55.950 it's basically something that 622 00:26:55.950 --> 00:26:58.390 comes from an asteroid, uh, 623 00:26:58.390 --> 00:27:01.230 whose characteristics are unusual, uh, 624 00:27:01.230 --> 00:27:03.970 that we have not, uh, yet, um, 625 00:27:03.970 --> 00:27:04.970 identified it. 626 00:27:06.250 --> 00:27:09.210 Andrew Dunkley: Wow. Okay, so we're 627 00:27:09.210 --> 00:27:09.690 still looking. 628 00:27:10.330 --> 00:27:12.890 Professor Fred Watson: We're still looking. There's a sort of sub 629 00:27:12.890 --> 00:27:14.540 mystery as well because, um, 630 00:27:17.450 --> 00:27:19.770 a detailed analysis of this, you can break 631 00:27:19.770 --> 00:27:22.370 that Group 4 stuff down into other smaller 632 00:27:22.370 --> 00:27:24.890 groups. And, uh, some of them 633 00:27:25.290 --> 00:27:28.210 Basically show signs of having had two 634 00:27:28.210 --> 00:27:31.080 different, uh, minerals in 635 00:27:31.080 --> 00:27:33.320 them before they entered the Earth's 636 00:27:33.320 --> 00:27:35.910 atmosphere. And, um, 637 00:27:36.240 --> 00:27:37.840 one would be typical of, 638 00:27:39.360 --> 00:27:42.360 uh, well known types of asteroids. And the 639 00:27:42.360 --> 00:27:44.880 other, as I said, doesn't correspond to any 640 00:27:44.959 --> 00:27:47.940 kind of known, um, group of, uh, 641 00:27:49.080 --> 00:27:51.840 um, cosmic spherules or meteorites. 642 00:27:52.260 --> 00:27:54.880 Uh, and it's really quite 643 00:27:54.880 --> 00:27:57.200 remarkable that this, you know, we're being 644 00:27:57.440 --> 00:27:59.720 bombarded by dust particles that come from 645 00:27:59.720 --> 00:28:01.960 somewhere which we haven't identified. 646 00:28:02.360 --> 00:28:02.840 Professor Fred Watson: Yeah. 647 00:28:02.920 --> 00:28:05.720 Andrew Dunkley: Wow. Um, could that mean they're from 648 00:28:05.800 --> 00:28:08.400 beyond our system or it's just a part of the 649 00:28:08.400 --> 00:28:09.160 system that we. 650 00:28:11.000 --> 00:28:11.720 Professor Fred Watson: I think it's. 651 00:28:11.720 --> 00:28:12.280 Andrew Dunkley: I don't know. 652 00:28:13.320 --> 00:28:15.320 Professor Fred Watson: Yeah, I think it's the other way around. Um, 653 00:28:15.400 --> 00:28:18.000 because the m. The team who've done the 654 00:28:18.000 --> 00:28:19.960 research on this, a very, very thorough piece 655 00:28:19.960 --> 00:28:22.520 of research, they've basically, 656 00:28:23.360 --> 00:28:25.820 um, as you would, you've used, uh, 657 00:28:25.820 --> 00:28:28.280 simulations, computer simulations 658 00:28:28.760 --> 00:28:30.920 to, to essentially work out 659 00:28:31.710 --> 00:28:33.990 what conditions these things formed in when 660 00:28:33.990 --> 00:28:36.630 they, um, melted coming through the Earth's 661 00:28:36.630 --> 00:28:39.630 atmosphere. And it suggested that the best 662 00:28:39.630 --> 00:28:42.630 fit they get to what they see, the sort of 663 00:28:42.630 --> 00:28:45.470 textures that are in the material fit 664 00:28:45.470 --> 00:28:47.390 with relatively low 665 00:28:47.790 --> 00:28:50.710 velocities, uh, 14 to 17 kilometres 666 00:28:50.710 --> 00:28:52.910 per second. Uh, which is 667 00:28:53.390 --> 00:28:55.750 pretty speedy when you think of it on Earth. 668 00:28:55.750 --> 00:28:58.470 But, um, uh, in space, that's a 669 00:28:58.470 --> 00:29:00.910 fairly modest, uh, space speed for a 670 00:29:00.910 --> 00:29:02.910 meteorite that typically will be more like 30 671 00:29:03.130 --> 00:29:05.930 kilometres per second. And so that 672 00:29:05.930 --> 00:29:08.690 low value, uh, suggests 673 00:29:08.690 --> 00:29:10.730 that possibly those 674 00:29:11.050 --> 00:29:13.930 particles originated in near 675 00:29:13.930 --> 00:29:16.850 Earth asteroids, um, ones 676 00:29:16.850 --> 00:29:19.810 that are, um, following a similar path 677 00:29:19.810 --> 00:29:22.570 through space to the Earth. And that 678 00:29:22.810 --> 00:29:25.690 might mean that we've got some sort of, 679 00:29:26.190 --> 00:29:28.890 um, in the Earth's environment, some 680 00:29:28.970 --> 00:29:31.650 sort of unusual asteroid 681 00:29:31.650 --> 00:29:34.140 that is not, not matched by all the ones that 682 00:29:34.140 --> 00:29:34.780 we know already. 683 00:29:35.180 --> 00:29:35.660 Professor Fred Watson: Wow. 684 00:29:35.660 --> 00:29:37.700 Andrew Dunkley: That'd be something, uh, that's probably 685 00:29:37.700 --> 00:29:39.100 gonna be hard to track down though. 686 00:29:39.580 --> 00:29:41.460 Professor Fred Watson: Yes, yes, that's probably right. And 687 00:29:41.460 --> 00:29:43.220 especially since it might not exist anymore, 688 00:29:43.220 --> 00:29:45.300 it may have collided and formed little bits 689 00:29:45.300 --> 00:29:47.900 that have basically rained down on the Earth. 690 00:29:47.900 --> 00:29:50.860 Andrew Dunkley: Yeah. Now, it wasn't Thea. Rusty just. 691 00:29:51.180 --> 00:29:52.660 Professor Fred Watson: No, it wasn't Thea. That's right. Yeah. 692 00:29:52.660 --> 00:29:54.380 Thanks, Rusty. It's not Thea. 693 00:29:55.110 --> 00:29:57.380 Andrew Dunkley: Um, for the record, Brownlee particles and 694 00:29:57.380 --> 00:29:59.860 cosmic spherules are closely related, but 695 00:29:59.860 --> 00:30:01.420 they are not exactly the same thing. 696 00:30:01.660 --> 00:30:02.300 Professor Fred Watson: Okay. 697 00:30:02.380 --> 00:30:05.280 Andrew Dunkley: They represent two different ages or types 698 00:30:05.280 --> 00:30:06.760 of micrometeorites. 699 00:30:07.320 --> 00:30:09.720 Professor Fred Watson: There you go. Thank you for checking that. 700 00:30:10.040 --> 00:30:11.400 Yes, that's all right. 701 00:30:11.430 --> 00:30:13.080 Andrew Dunkley: Um, yeah, they're very close, but they're 702 00:30:13.080 --> 00:30:14.000 not, not the same. 703 00:30:14.000 --> 00:30:15.160 Professor Fred Watson: So I was on the right track. 704 00:30:15.240 --> 00:30:16.600 Andrew Dunkley: You were, yes. 705 00:30:17.320 --> 00:30:20.030 And you can read all about that at, uh, 706 00:30:20.279 --> 00:30:23.120 the AstroDailyPod Galaxy website. Um, and 707 00:30:23.120 --> 00:30:25.720 the article Was published where, 708 00:30:25.880 --> 00:30:27.560 Fred Watson, I've lost the science advances. 709 00:30:29.240 --> 00:30:31.170 That's right, yes. Want to read the whole 710 00:30:31.170 --> 00:30:32.770 thing before bed so you sleep well? 711 00:30:34.770 --> 00:30:35.330 Professor Fred Watson: Yep. 712 00:30:35.410 --> 00:30:35.850 Professor Fred Watson: Yeah. 713 00:30:35.850 --> 00:30:37.810 Andrew Dunkley: This is Space Nuts with Andrew Dunkley and 714 00:30:37.810 --> 00:30:38.930 Professor Fred Watson Watson. 715 00:30:40.930 --> 00:30:43.810 Professor Fred Watson: We choose to go to the moon in this decade 716 00:30:43.810 --> 00:30:46.690 and do the other things, not because they are 717 00:30:46.690 --> 00:30:49.570 easy, but because they are hard, these nuts. 718 00:30:50.850 --> 00:30:53.610 Andrew Dunkley: Our, ah, final storey today takes us 719 00:30:53.610 --> 00:30:56.250 to the edge of our galaxy. Well, it takes us 720 00:30:56.250 --> 00:30:58.130 from the centre of our galaxy right out to 721 00:30:58.130 --> 00:30:59.650 the edge of our galaxy because we're talking 722 00:30:59.650 --> 00:31:01.490 about the whole thing lock, stock and barrel. 723 00:31:02.280 --> 00:31:04.920 And it appears, Fred Watson, with some very 724 00:31:04.920 --> 00:31:07.640 clever scientific brains in action, 725 00:31:07.800 --> 00:31:10.480 that, uh, our galaxy stretches out further 726 00:31:10.480 --> 00:31:11.320 than we thought. 727 00:31:13.000 --> 00:31:15.760 Professor Fred Watson: Uh, it does. It looks as though the spiral 728 00:31:15.760 --> 00:31:17.480 arms are longer than we thought they were. 729 00:31:18.680 --> 00:31:21.360 And I think this is a very nice piece of 730 00:31:21.360 --> 00:31:23.720 work, uh, as, uh, I hinted before, 731 00:31:24.360 --> 00:31:27.200 uh, partly because it uses a technique that I 732 00:31:27.200 --> 00:31:29.840 think is really extraordinary. It's a very 733 00:31:29.840 --> 00:31:31.880 powerful technique, uh, using what we call 734 00:31:31.880 --> 00:31:34.390 light echoes. Um, 735 00:31:35.130 --> 00:31:37.650 so the storey, basically, to set this in 736 00:31:37.650 --> 00:31:40.450 context, it's very hard for us to 737 00:31:40.450 --> 00:31:42.850 produce a map of what our own galaxy looks 738 00:31:42.850 --> 00:31:45.610 like. And that's because we're embedded in 739 00:31:45.690 --> 00:31:48.690 one of the spiral arms. Uh, the 740 00:31:48.690 --> 00:31:50.690 stars that we see when we look at the Milky 741 00:31:50.690 --> 00:31:53.010 Way. They're stars that, uh, fellow 742 00:31:53.010 --> 00:31:55.050 travellers in the spiral arms with our, uh, 743 00:31:55.050 --> 00:31:57.850 sun and solar system. But they only go out to 744 00:31:57.850 --> 00:32:00.370 1000 light years or so because the spiral 745 00:32:00.370 --> 00:32:02.490 arms are so dusty that you can't really 746 00:32:02.490 --> 00:32:05.250 penetrate much beyond that. Um, 747 00:32:05.270 --> 00:32:07.750 and if you were relying only on visible 748 00:32:07.910 --> 00:32:10.710 light, uh, it would be 749 00:32:10.710 --> 00:32:13.270 like trying to draw a map 750 00:32:13.830 --> 00:32:16.470 of the whole of Dubbo from 751 00:32:16.470 --> 00:32:19.340 standing outside Dubbo jail there on, um, 752 00:32:20.250 --> 00:32:22.550 uh, forgotten. Is that Macquarie Street? 753 00:32:22.550 --> 00:32:23.670 Andrew Dunkley: Macquarie street, yeah. 754 00:32:23.670 --> 00:32:24.470 Professor Fred Watson: Yes, yes. 755 00:32:24.470 --> 00:32:26.650 Andrew Dunkley: Oh, for the record, they're putting a, um, 756 00:32:27.110 --> 00:32:28.830 they've taken down the public building in 757 00:32:28.830 --> 00:32:30.190 front of the old Dubbo jail. 758 00:32:30.190 --> 00:32:30.950 Professor Fred Watson: Oh, there you go. 759 00:32:30.950 --> 00:32:33.790 Andrew Dunkley: Now they're turning it into a public 760 00:32:33.790 --> 00:32:34.510 common. Common. 761 00:32:35.310 --> 00:32:36.430 Professor Fred Watson: I, uh, like that idea. 762 00:32:36.590 --> 00:32:38.230 Andrew Dunkley: That's going to look very nice when it's 763 00:32:38.230 --> 00:32:38.510 done. 764 00:32:39.070 --> 00:32:41.070 Professor Fred Watson: So that would improve your view of the city 765 00:32:41.070 --> 00:32:43.990 of Dubbo, but it still might not let you make 766 00:32:43.990 --> 00:32:46.640 a map of Dubbo from just there. Uh, 767 00:32:46.750 --> 00:32:48.870 and that's how we are in our galaxy. If 768 00:32:48.870 --> 00:32:51.550 you're relying on visible light observations, 769 00:32:52.190 --> 00:32:54.830 uh, all you're seeing when you look 770 00:32:55.310 --> 00:32:57.550 is the neighbourhood of, uh, our 771 00:32:57.870 --> 00:32:59.990 spiral arm, a local spiral arm. You don't get 772 00:32:59.990 --> 00:33:02.430 any hint or inclination of the structure of 773 00:33:02.430 --> 00:33:05.430 the galaxy, uh, beyond that. And in 774 00:33:05.430 --> 00:33:08.360 particular, you know, if we see 775 00:33:08.840 --> 00:33:11.080 a thousand light years or so, there's another 776 00:33:11.080 --> 00:33:12.760 Hundred thousand that we're not seeing 777 00:33:12.760 --> 00:33:14.480 because that's about the diameter of, ah, our 778 00:33:14.480 --> 00:33:17.040 galaxy. So, um, ah, the 779 00:33:17.040 --> 00:33:19.980 situation improves when you use infrared, uh, 780 00:33:20.520 --> 00:33:22.770 radiation. You can sort of penetrate, uh, 781 00:33:23.160 --> 00:33:25.880 through the dust and see actually the centre, 782 00:33:25.880 --> 00:33:27.760 towards the centre of our galaxy. That's how 783 00:33:27.760 --> 00:33:30.040 we know about the black hole in the centre of 784 00:33:30.040 --> 00:33:31.680 our galaxy, because we could see stars 785 00:33:31.680 --> 00:33:34.380 orbiting around it. Um, but 786 00:33:34.380 --> 00:33:37.380 it improves even more on a broader scale if 787 00:33:37.380 --> 00:33:39.460 you can use radio telescopes, because you can 788 00:33:39.460 --> 00:33:42.460 plot, um, where the clouds of 789 00:33:42.460 --> 00:33:45.460 hydrogen gas called hydrogen, uh, which 790 00:33:45.700 --> 00:33:48.380 radiates in, uh, radio waves, uh, with a 791 00:33:48.380 --> 00:33:51.260 wavelength of 21 centimetres, uh, that you 792 00:33:51.260 --> 00:33:53.140 can plot out. But if you're going to try and 793 00:33:53.140 --> 00:33:55.700 draw a map, you do need to do some modelling 794 00:33:55.700 --> 00:33:57.380 with that. You've got to assume things about 795 00:33:57.380 --> 00:33:59.740 the rotation of the galaxy so it doesn't just 796 00:33:59.740 --> 00:34:02.660 give you a direct map, map. And that could 797 00:34:02.660 --> 00:34:04.900 be wrong. We could have that little bit of it 798 00:34:04.900 --> 00:34:07.900 wrong, uh, you know, uh, the stuff that comes 799 00:34:07.900 --> 00:34:10.820 from the radio observations. So 800 00:34:10.820 --> 00:34:13.660 what's happened now is it's a 801 00:34:13.660 --> 00:34:16.580 team, uh, I think they're based in Italy, 802 00:34:16.780 --> 00:34:19.780 uh, and what they've done 803 00:34:19.940 --> 00:34:22.360 is used, um, 804 00:34:23.300 --> 00:34:26.140 a direct method of kind of 805 00:34:26.140 --> 00:34:29.020 setting up a standard ruler. Uh, because if 806 00:34:29.020 --> 00:34:30.700 you've got a standard ruler and you can see 807 00:34:30.700 --> 00:34:32.730 it in deep space, then you know how far away 808 00:34:32.959 --> 00:34:34.999 it is because you can measure how long it 809 00:34:34.999 --> 00:34:37.039 appears to be. And if you know how long it 810 00:34:37.039 --> 00:34:39.559 is, which is what a standard ruler is, then 811 00:34:39.559 --> 00:34:42.559 you know how far away it is. And that's 812 00:34:42.559 --> 00:34:45.199 what they're doing. They have. And it goes 813 00:34:45.199 --> 00:34:47.479 back to something we mentioned earlier in the 814 00:34:47.479 --> 00:34:49.999 show, gamma ray bursts. These bursts of gamma 815 00:34:49.999 --> 00:34:52.399 radiation, those 816 00:34:52.399 --> 00:34:55.399 bursts, uh, don't just directly come to 817 00:34:55.399 --> 00:34:57.959 us, they also bounce off or are 818 00:34:57.959 --> 00:35:00.830 reflected by clouds of dust in our 819 00:35:00.830 --> 00:35:03.830 spiral arms. And, uh, so 820 00:35:04.310 --> 00:35:07.110 by timing how long, 821 00:35:07.710 --> 00:35:10.510 uh, it takes for these echoes, as 822 00:35:10.510 --> 00:35:12.630 they're called, light echoes, even though 823 00:35:12.630 --> 00:35:15.550 it's gamma radiation, uh, to what 824 00:35:15.550 --> 00:35:18.030 the delay is between a light 825 00:35:18.030 --> 00:35:21.030 echo and the, uh, source itself, 826 00:35:21.030 --> 00:35:22.750 which is the gamma ray burst, I should say 827 00:35:22.750 --> 00:35:24.710 they probably come from collapsing 828 00:35:25.510 --> 00:35:27.990 massive stars or merger of neutron 829 00:35:27.990 --> 00:35:30.870 stars, uh, very energetic events 830 00:35:31.010 --> 00:35:32.930 because they're bright in gamma radiation. 831 00:35:33.330 --> 00:35:36.130 But if you look at a light echo from a gamma 832 00:35:36.130 --> 00:35:38.850 ray burst, it gives you a scale to this, 833 00:35:39.010 --> 00:35:41.250 you know, um, how far. 834 00:35:42.850 --> 00:35:44.770 Basically, uh, it gives you a standard ruler, 835 00:35:44.840 --> 00:35:47.370 um, because you can time it accurately, you 836 00:35:47.370 --> 00:35:50.090 know that 300,000 kilometres per second is 837 00:35:50.090 --> 00:35:52.490 the speed of gamma rays through space. And, 838 00:35:52.490 --> 00:35:54.730 you know, if you know how far away it's gone 839 00:35:54.730 --> 00:35:56.610 in that time, then that gives you a distance 840 00:35:56.610 --> 00:35:59.220 measure. So you've got a standard ruler. Uh, 841 00:35:59.250 --> 00:36:01.490 it's a very, very nice way of doing this. 842 00:36:01.490 --> 00:36:04.230 And, um, using that, uh, these, 843 00:36:04.440 --> 00:36:07.390 uh, scientists, um, as I 844 00:36:07.390 --> 00:36:10.000 said, uh, at least the lead author is, uh, 845 00:36:10.000 --> 00:36:12.870 certainly in Italy at ENAF in Milano, 846 00:36:13.160 --> 00:36:16.070 uh, uh, they've done this work 847 00:36:16.150 --> 00:36:18.430 looking at these gamma ray bursts with their 848 00:36:18.430 --> 00:36:20.750 light echoes, and that allows them to 849 00:36:20.750 --> 00:36:23.720 calculate basically the size of our, uh, 850 00:36:23.720 --> 00:36:26.110 spiral arms without relying on any kind of 851 00:36:26.110 --> 00:36:28.910 modelling. And so 852 00:36:28.910 --> 00:36:31.590 they think that the new 853 00:36:31.590 --> 00:36:34.570 observations indicate that, uh, our spiral 854 00:36:34.570 --> 00:36:36.610 arms are something like 10% 855 00:36:37.170 --> 00:36:39.410 longer than we thought they were. Wow, 856 00:36:39.410 --> 00:36:39.740 that's, uh. 857 00:36:39.740 --> 00:36:40.050 Professor Fred Watson: A lot. 858 00:36:40.450 --> 00:36:42.890 Professor Fred Watson: Yes. That's significant, isn't it? It's 859 00:36:42.890 --> 00:36:45.250 really, um. You know, this is. As I said, 860 00:36:45.250 --> 00:36:47.490 this is very nice, uh, nice astronomy. 861 00:36:48.050 --> 00:36:50.810 Andrew Dunkley: It is indeed. Yeah. Um, of 862 00:36:50.810 --> 00:36:53.410 course, as you say, we can't really look at 863 00:36:53.410 --> 00:36:55.770 our galaxy. We don't know exactly what it 864 00:36:55.770 --> 00:36:57.810 looks like. Um, there's a lot of science that 865 00:36:57.810 --> 00:37:00.750 they've put together to try and create 866 00:37:00.750 --> 00:37:02.870 the image of it. And even in this particular 867 00:37:03.030 --> 00:37:05.350 storey, uh, which is in the Universe Today 868 00:37:05.430 --> 00:37:07.670 dot com, they've got an artist's impression 869 00:37:07.670 --> 00:37:10.550 of what this new, uh, look is like. 870 00:37:10.550 --> 00:37:11.830 Professor Fred Watson: Yes. That's all you can do. 871 00:37:11.910 --> 00:37:14.470 Andrew Dunkley: Reminds me of an upside down snail. 872 00:37:15.750 --> 00:37:18.430 Professor Fred Watson: It does, yes, that's right. I see what you 873 00:37:18.430 --> 00:37:19.350 mean. Yes, yes. 874 00:37:22.150 --> 00:37:24.470 Andrew Dunkley: Or a squid. Could be a squid. 875 00:37:24.470 --> 00:37:25.830 Professor Fred Watson: Could be a squid, yeah. 876 00:37:26.430 --> 00:37:29.190 Andrew Dunkley: Uh, but in real terms we just have 877 00:37:29.190 --> 00:37:32.090 to. It's an edge. Very, very educated 878 00:37:32.090 --> 00:37:33.010 guess, I suppose. 879 00:37:33.950 --> 00:37:36.930 Professor Fred Watson: Um, yes, it is. It's a measurement. 880 00:37:37.170 --> 00:37:40.090 So you're right, 881 00:37:40.090 --> 00:37:41.530 it's an artist's impression. That's really 882 00:37:41.530 --> 00:37:43.730 the only way we can depict the Milky Way. 883 00:37:43.970 --> 00:37:45.650 Some of the depictions are very, very good 884 00:37:45.650 --> 00:37:47.810 and they rely on the very best radio and 885 00:37:47.810 --> 00:37:50.130 infrared observations that have been made. 886 00:37:50.210 --> 00:37:52.690 But this is going to modify it a little bit 887 00:37:52.690 --> 00:37:55.530 by our new knowledge of the spiral arms. And 888 00:37:55.530 --> 00:37:58.060 I should say, um, this, the, um. 889 00:37:58.480 --> 00:38:01.300 It's the Chandra satellite, uh, which is a, 890 00:38:01.300 --> 00:38:04.230 ah, an X ray observatory, um, 891 00:38:04.240 --> 00:38:07.180 by. Operated by NASA, uh, 892 00:38:07.200 --> 00:38:09.680 that has been used to make the measurements. 893 00:38:10.080 --> 00:38:13.000 And I do like the headline on a little, uh, 894 00:38:13.000 --> 00:38:15.040 NASA video that there is Here, which is 895 00:38:15.040 --> 00:38:17.920 NASA's Chandra examines Milky Way at 896 00:38:17.920 --> 00:38:18.720 Arm's Length. 897 00:38:18.720 --> 00:38:21.680 Andrew Dunkley: Yeah, nice. Um, very 898 00:38:21.680 --> 00:38:22.240 well done. 899 00:38:22.240 --> 00:38:25.200 Professor Fred Watson: Clever, clever. Yeah, they are. 900 00:38:25.200 --> 00:38:26.160 There's some good people there. 901 00:38:26.160 --> 00:38:28.960 Andrew Dunkley: Uh, so the articles in Universe Today, but 902 00:38:28.960 --> 00:38:31.640 you can read it in a deeper form 903 00:38:31.800 --> 00:38:34.660 through the NASA website or the, uh, 904 00:38:35.000 --> 00:38:37.160 Astronomy and Astrophysics Journal, I think, 905 00:38:37.160 --> 00:38:39.560 has published, uh, the full paper, which is. 906 00:38:40.120 --> 00:38:42.680 Professor Fred Watson: Yeah, that's the European journal. 907 00:38:43.000 --> 00:38:45.920 Andrew Dunkley: Lots of numbers in it. Yeah, lots and 908 00:38:45.920 --> 00:38:48.800 lots of numbers. Numbers that are too big 909 00:38:48.800 --> 00:38:49.640 for my brain. 910 00:38:51.880 --> 00:38:54.600 All right, uh, that's where we end the show. 911 00:38:54.600 --> 00:38:55.630 Fred Watson, thank you very much. 912 00:38:55.780 --> 00:38:56.020 Professor Fred Watson: Much. 913 00:38:56.100 --> 00:38:58.660 Professor Fred Watson: Oh, a pleasure. Uh, as you said at the 914 00:38:58.660 --> 00:38:59.980 beginning, some nice storeys there. 915 00:38:59.980 --> 00:39:01.460 Andrew Dunkley: Yeah. I'm very glad to be able to 916 00:39:01.460 --> 00:39:02.260 Professor Fred Watson: share them with you. 917 00:39:02.260 --> 00:39:04.660 Andrew Dunkley: Indeed. Uh, we'll catch you real soon. Thank 918 00:39:04.660 --> 00:39:05.060 you, Fred Watson. 919 00:39:05.380 --> 00:39:06.660 Professor Fred Watson: No worries. Thanks, Andrew. 920 00:39:06.660 --> 00:39:08.460 Andrew Dunkley: Professor Fred Watson Watson, astronomer at 921 00:39:08.460 --> 00:39:10.660 large, and, uh, as I say, between episodes, 922 00:39:10.660 --> 00:39:13.500 Visit our website, spacenutspodcast.com or 923 00:39:13.500 --> 00:39:16.100 spacenuts IO if you're a lazy 924 00:39:16.100 --> 00:39:18.820 typist and you can have a look around, 925 00:39:18.820 --> 00:39:21.540 visit our shop. Uh, sign up for the Astronomy 926 00:39:21.540 --> 00:39:23.260 AstroDailyPod feed. Send us some questions or 927 00:39:23.260 --> 00:39:25.420 comments through the Ask me anything button 928 00:39:25.420 --> 00:39:28.240 at the top. Ama. Uh, you might want to become 929 00:39:28.320 --> 00:39:30.320 a supporter. You can do that too. And don't 930 00:39:30.320 --> 00:39:33.080 forget to leave reviews of Space Nuts, your 931 00:39:33.080 --> 00:39:35.320 favourite podcasting platform. And thanks to 932 00:39:35.320 --> 00:39:37.960 Huw in the studio because he didn't turn up 933 00:39:37.960 --> 00:39:40.560 today. And from me, Andrew Duckling. Whoops. 934 00:39:40.720 --> 00:39:42.320 Uh, thanks for your company. We'll catch you 935 00:39:42.320 --> 00:39:44.640 on the next episode of Space Nuts. Bye. Bye. 936 00:39:45.920 --> 00:39:48.120 You've been listening to the Space Nuts 937 00:39:48.120 --> 00:39:51.080 podcast, available at 938 00:39:51.080 --> 00:39:53.040 Apple Podcasts, Spotify, 939 00:39:53.460 --> 00:39:56.340 iHeartRadio or your favourite podcast player. 940 00:39:56.420 --> 00:39:59.380 You can also stream on demand@bytes.um.com. 941 00:39:59.700 --> 00:40:01.780 Professor Fred Watson: this has been another quality podcast 942 00:40:01.780 --> 00:40:03.940 production from bytes.um.com.