WEBVTT 0 00:00:00.400 --> 00:00:02.200 Andrew Dunkley: Hello again. Thanks for joining us. This is a 1 00:00:02.200 --> 00:00:05.120 Q and A edition of Space Nuts. We talk 2 00:00:05.120 --> 00:00:07.720 astronomy, space science, and answer 3 00:00:07.720 --> 00:00:10.280 audience questions. Well, maybe we won't do 4 00:00:10.280 --> 00:00:12.000 one of those three things today. I don't 5 00:00:12.000 --> 00:00:14.160 know. We'll see how it goes. Uh, we've got a 6 00:00:14.160 --> 00:00:16.060 lot of questions to get through today. Um, 7 00:00:16.060 --> 00:00:17.920 Fred Watson reckons some of these are very, 8 00:00:17.920 --> 00:00:20.240 very tricky, so we'll see how it all pans 9 00:00:20.240 --> 00:00:23.000 out. Um, a question about the expanding 10 00:00:23.000 --> 00:00:25.820 universe. Never had one of those before. Uh, 11 00:00:25.820 --> 00:00:28.510 a question about gravitons. Never had one of 12 00:00:28.510 --> 00:00:31.470 those before. Yes, we have. Uh, photons 13 00:00:31.710 --> 00:00:34.710 and weight shift. That's all coming up on 14 00:00:34.710 --> 00:00:37.310 this edition of space nuts. 15 15 00:00:37.390 --> 00:00:37.950 seconds. 16 00:00:37.950 --> 00:00:40.278 Professor Fred Watson: Guidance is internal. 10, 17 00:00:40.422 --> 00:00:43.310 9. Ignition sequence start. 18 00:00:43.549 --> 00:00:46.357 Space nuts. 5, 4, 3. 2. 1, 2, 19 00:00:46.428 --> 00:00:49.230 3, 4, 5, 5, 4, 3, 2, 1. 20 00:00:49.310 --> 00:00:52.070 Andrew Dunkley: Space nuts. Astronauts report it feels 21 00:00:52.070 --> 00:00:54.990 good. And joining us once more to 22 00:00:54.990 --> 00:00:57.850 unravel all of that, or maybe ravel it 23 00:00:57.850 --> 00:00:59.370 up even more, is Professor Fred Watson 24 00:00:59.370 --> 00:01:00.970 Watson, astronomer at, uh, large. Hello, 25 00:01:00.970 --> 00:01:01.330 Fred Watson. 26 00:01:01.650 --> 00:01:04.650 Professor Fred Watson: Hello, Andrew. I do feel pretty ravelled at 27 00:01:04.650 --> 00:01:05.010 the moment. 28 00:01:05.010 --> 00:01:07.770 Andrew Dunkley: Yeah, look, we have got some tricky 29 00:01:07.770 --> 00:01:10.750 questions, but before we get to those, uh, 30 00:01:10.750 --> 00:01:13.210 we've received a note from Rennie in 31 00:01:13.210 --> 00:01:13.970 California. 32 00:01:13.990 --> 00:01:16.490 Uh, Rennie quite regularly sends questions 33 00:01:16.490 --> 00:01:18.850 into us, but he sent us a really lovely note 34 00:01:19.010 --> 00:01:22.010 which I want to share. Uh, he says no 35 00:01:22.010 --> 00:01:24.570 questions today, just to thank you. I try to 36 00:01:24.570 --> 00:01:26.930 absorb as much information as I can listening 37 00:01:26.930 --> 00:01:28.970 to your podcast. And when I'm engaged in a 38 00:01:28.970 --> 00:01:31.070 convers conversation with my two grandsons 39 00:01:31.070 --> 00:01:33.870 aged 15 and 12, I try to excite 40 00:01:33.870 --> 00:01:36.430 them and get them to think about our place in 41 00:01:36.430 --> 00:01:39.270 the universe and how it behaves. Now it's 42 00:01:39.270 --> 00:01:41.670 paying off with the announcement that my 43 00:01:41.670 --> 00:01:44.390 older grandson wants to carry on in college 44 00:01:44.390 --> 00:01:47.150 with some form of education in astronomy 45 00:01:47.310 --> 00:01:50.310 or particle physics. Thank you for paying 46 00:01:50.310 --> 00:01:52.630 it forward, Renny. Isn't that lovely? 47 00:01:52.630 --> 00:01:54.510 Professor Fred Watson: Yeah, that's great. Absolutely great. 48 00:01:54.920 --> 00:01:56.990 Andrew Dunkley: Uh, I love it when we get feedback from 49 00:01:56.990 --> 00:01:59.730 people that, that become inspired 50 00:02:00.450 --> 00:02:01.330 despite us. 51 00:02:04.130 --> 00:02:05.410 No, I mean, it's fantastic. 52 00:02:05.410 --> 00:02:05.690 Professor Fred Watson: It is. 53 00:02:05.690 --> 00:02:07.730 Andrew Dunkley: I'm really, really pleased. Really pleased. 54 00:02:07.730 --> 00:02:10.010 So, um, pass on our regards, Rennie, to your 55 00:02:10.010 --> 00:02:12.250 boys or, uh, your grandsons, um, and wish 56 00:02:12.250 --> 00:02:14.850 them well and. Yeah, look, just. 57 00:02:15.410 --> 00:02:17.490 I do the same thing with my grandson and 58 00:02:17.570 --> 00:02:20.050 three granddaughters. Um, I talk to them 59 00:02:20.370 --> 00:02:22.090 whenever there's something interesting to 60 00:02:22.090 --> 00:02:24.490 talk about, and there usually is, uh, in the 61 00:02:24.490 --> 00:02:27.330 astronomical world. And, um, I show 62 00:02:27.330 --> 00:02:29.870 them the images I take with the Telesco, and 63 00:02:29.870 --> 00:02:32.150 I've even had them outside looking up at the 64 00:02:32.150 --> 00:02:35.110 moon. And, um, yeah, it's captivating. Once, 65 00:02:35.110 --> 00:02:37.310 once they, you know, once you can convince 66 00:02:37.310 --> 00:02:38.590 them to actually get outside. 67 00:02:39.690 --> 00:02:42.430 Um, you know, the universe is their 68 00:02:42.430 --> 00:02:45.070 oyster. It's, uh, it's good 69 00:02:45.070 --> 00:02:47.390 stuff. So lovely to hear from you, Rennie. 70 00:02:47.390 --> 00:02:49.150 And that is really fabulous news. 71 00:02:50.110 --> 00:02:51.510 Are you ready for your first question, 72 00:02:51.510 --> 00:02:51.950 Fred Watson? 73 00:02:53.230 --> 00:02:55.590 Professor Fred Watson: Well, after a. Yes. After a build up like 74 00:02:55.590 --> 00:02:56.910 that, I guess we've got to tackle them, 75 00:02:56.910 --> 00:02:57.390 haven't we? 76 00:02:57.450 --> 00:02:58.670 Andrew Dunkley: Uh, we probably should. 77 00:02:58.830 --> 00:03:00.510 Professor Fred Watson: You're right, in a way. You know, the 78 00:03:00.510 --> 00:03:02.410 ultimate notes, I guess, 79 00:03:03.450 --> 00:03:06.370 is to provide that little bit of perhaps 80 00:03:06.370 --> 00:03:09.130 inspiration that might lead people to do 81 00:03:09.130 --> 00:03:11.330 things that might one day change the world. 82 00:03:11.330 --> 00:03:12.010 Who knows? 83 00:03:12.250 --> 00:03:14.530 Andrew Dunkley: Yep, you just don't know. You just don't 84 00:03:14.530 --> 00:03:17.530 know. Maybe that's our lot in life is to just 85 00:03:18.410 --> 00:03:20.770 try to inspire, uh, just a handful of people 86 00:03:20.770 --> 00:03:23.290 to pick up the baton, Fred Watson. Who knows? 87 00:03:24.570 --> 00:03:27.290 All right, question one. It's like a test, 88 00:03:27.290 --> 00:03:27.850 isn't it? 89 00:03:27.930 --> 00:03:30.430 Question one. Uh, if space is 90 00:03:30.430 --> 00:03:32.430 expanding faster than the speed of light, 91 00:03:32.910 --> 00:03:35.470 then in millions or billions of years from 92 00:03:35.470 --> 00:03:38.110 now, will our night sky be completely black 93 00:03:38.590 --> 00:03:41.000 or a completely black void? Um, 94 00:03:41.860 --> 00:03:44.789 uh, or completely black, devoid of 95 00:03:44.789 --> 00:03:47.750 all light except our local solar system. That 96 00:03:47.750 --> 00:03:50.470 comes from Clint. Uh, this is 97 00:03:50.470 --> 00:03:53.310 something that has come up occasionally and I 98 00:03:53.310 --> 00:03:55.990 think even in one of our most recent 99 00:03:55.990 --> 00:03:58.390 episodes, we were talking about the expansion 100 00:03:58.390 --> 00:04:00.670 of the universe and its significance. And, 101 00:04:00.810 --> 00:04:02.930 and I think in our Q and A episode, someone 102 00:04:02.930 --> 00:04:04.890 asked about the expansion of the universe. 103 00:04:05.680 --> 00:04:07.850 Um, so here it is again. 104 00:04:08.820 --> 00:04:11.460 Um, we are, ah, 105 00:04:11.460 --> 00:04:13.970 expanding, and it's 106 00:04:13.970 --> 00:04:16.090 expanding at an accelerating rate. Although 107 00:04:16.090 --> 00:04:17.970 it's debatable whether or not that 108 00:04:17.970 --> 00:04:20.890 acceleration is actually as m. Significant 109 00:04:20.970 --> 00:04:23.690 as it was. That is a 110 00:04:23.690 --> 00:04:26.450 separate debate. Um, but I think it's pretty 111 00:04:26.450 --> 00:04:29.410 clear that in the long distant future 112 00:04:29.410 --> 00:04:32.280 of this universe, it will become a black 113 00:04:32.280 --> 00:04:33.200 void, won't it? 114 00:04:34.380 --> 00:04:37.280 Professor Fred Watson: Uh, yes. So the answer to Clint's question 115 00:04:37.280 --> 00:04:37.920 is yes. 116 00:04:38.240 --> 00:04:39.200 Andrew Dunkley: Okay, question 117 00:04:41.120 --> 00:04:43.980 Professor Fred Watson: no. Exactly. As you said, um, 118 00:04:43.980 --> 00:04:46.960 if you've got, um. So 119 00:04:47.840 --> 00:04:50.200 when you say the universe is expanding more 120 00:04:50.200 --> 00:04:52.080 than the speed of light, you've got to be a 121 00:04:52.080 --> 00:04:54.080 bit specific because really what you're 122 00:04:54.080 --> 00:04:57.050 talking about is objects within 123 00:04:57.050 --> 00:04:59.970 the universe which are being carried along by 124 00:04:59.970 --> 00:05:02.650 the expansion of the universe. And so, 125 00:05:03.020 --> 00:05:05.530 uh, there will be, at a certain 126 00:05:05.530 --> 00:05:07.770 distance from us now, 127 00:05:08.410 --> 00:05:10.970 objects whose, what we call the recession 128 00:05:10.970 --> 00:05:13.210 velocity is faster than the speed of light, 129 00:05:13.690 --> 00:05:16.610 but they're actually, they're beyond 130 00:05:16.610 --> 00:05:18.450 the wall that we can't see beyond anyway, 131 00:05:18.450 --> 00:05:20.410 which is the cosmic microwave background 132 00:05:20.410 --> 00:05:22.610 radiation. But you can imagine as the 133 00:05:22.610 --> 00:05:25.530 expansion continues to accelerate, and you're 134 00:05:25.530 --> 00:05:27.330 right, it is still thought to be 135 00:05:27.330 --> 00:05:29.690 accelerating. We just don't quite know 136 00:05:29.690 --> 00:05:31.770 whether that acceleration is a constant. 137 00:05:31.770 --> 00:05:34.770 That's the thing you were alluding 138 00:05:34.770 --> 00:05:37.290 to because there's some evidence that 139 00:05:37.370 --> 00:05:39.690 maybe the acceleration is reducing, 140 00:05:40.250 --> 00:05:42.490 but nevertheless it's still accelerating. So 141 00:05:42.490 --> 00:05:45.050 it's still getting bigger, faster, uh, all 142 00:05:45.050 --> 00:05:47.450 the time. And so what that would do, 143 00:05:48.500 --> 00:05:51.280 um, you can, you can sort of 144 00:05:51.280 --> 00:05:53.560 imagine in your head what this situation 145 00:05:53.560 --> 00:05:55.680 would lead to. It means that the, 146 00:05:56.960 --> 00:05:59.600 the, the sort of black horizon, the horizon 147 00:05:59.920 --> 00:06:02.320 which is where light can never get to you 148 00:06:02.320 --> 00:06:04.440 because it's being carried away. The objects 149 00:06:04.440 --> 00:06:05.920 are being carried away faster than the speed 150 00:06:05.920 --> 00:06:08.400 of light. That black horizon will, will 151 00:06:08.400 --> 00:06:11.200 approach, um, it'll get nearer 152 00:06:11.200 --> 00:06:14.040 as the universe's expansion continues to 153 00:06:14.040 --> 00:06:16.720 accelerate. So eventually you can imagine 154 00:06:16.720 --> 00:06:19.590 that maybe you would see just 155 00:06:19.590 --> 00:06:22.130 the other galaxies in the Local Group, uh, 156 00:06:22.130 --> 00:06:24.670 which is Andromeda and the, uh, triangular 157 00:06:24.830 --> 00:06:27.470 whirlpool galaxy and things like that. But 158 00:06:27.470 --> 00:06:29.630 eventually, yeah, it might just be 159 00:06:30.430 --> 00:06:33.120 objects in our own solar system, uh, 160 00:06:33.310 --> 00:06:36.030 which makes astronomy a little bit of a. 161 00:06:36.270 --> 00:06:38.910 Boring. Yeah. 162 00:06:38.910 --> 00:06:39.350 Yeah. 163 00:06:39.350 --> 00:06:41.230 Andrew Dunkley: Well, let's go see what we can find. Oh, 164 00:06:41.230 --> 00:06:41.870 there's the moon. 165 00:06:41.950 --> 00:06:43.950 Professor Fred Watson: Yeah. Yeah. Oh, wait, it's gone. 166 00:06:46.630 --> 00:06:48.070 Andrew Dunkley: Well, it's moving away from us too. 167 00:06:48.070 --> 00:06:50.430 Professor Fred Watson: So it is rather slower than the speed of 168 00:06:50.430 --> 00:06:52.630 light. Yeah. Six centimetres a year. 169 00:06:52.710 --> 00:06:54.550 Andrew Dunkley: I can't imagine this is going to happen in an 170 00:06:54.550 --> 00:06:55.590 awful hurry, Fred Watson. 171 00:06:55.590 --> 00:06:58.030 Professor Fred Watson: No, it's not. It's very, very long way down 172 00:06:58.030 --> 00:06:59.350 the track. And of course, from our 173 00:06:59.350 --> 00:07:01.490 perspective here on, ah, Earth, long, uh, 174 00:07:01.750 --> 00:07:04.630 before anything like that takes place, 175 00:07:04.790 --> 00:07:07.710 um, we'll have been 176 00:07:07.710 --> 00:07:09.870 confronted by the expansion of the sun 177 00:07:09.870 --> 00:07:12.470 itself, um, as it turns into 178 00:07:12.710 --> 00:07:13.830 a red giant star. 179 00:07:14.340 --> 00:07:16.740 Andrew Dunkley: Yeah. Who knows where we'll be in the 180 00:07:16.740 --> 00:07:19.700 universe by then. We might have moved out 181 00:07:19.700 --> 00:07:21.580 into other parts of the galaxy by then if 182 00:07:21.580 --> 00:07:24.540 we've managed, um, to find some kind of 183 00:07:24.540 --> 00:07:27.380 propulsion system or learn how to fold 184 00:07:27.380 --> 00:07:29.610 space or whatever it is you need to do. Uh, 185 00:07:29.700 --> 00:07:32.700 maybe develop wormholes and be able 186 00:07:32.700 --> 00:07:34.100 to travel mega distances. 187 00:07:34.420 --> 00:07:37.220 Professor Fred Watson: Yeah. Fast. You're the person, you're the 188 00:07:37.220 --> 00:07:39.060 science fiction writer. You've got to tell us 189 00:07:39.060 --> 00:07:40.260 what it is we're going to do. 190 00:07:40.560 --> 00:07:43.300 Andrew Dunkley: Uh, I'm working, um, uh, on 191 00:07:44.100 --> 00:07:46.220 warp, uh, warp travel at the moment. 192 00:07:46.220 --> 00:07:46.780 Professor Fred Watson: Oh, good. 193 00:07:47.020 --> 00:07:49.500 Andrew Dunkley: In m. My. In my novels. So, 194 00:07:49.660 --> 00:07:52.420 yeah, I'm doing the final editing at this 195 00:07:52.420 --> 00:07:55.020 stage and it's, uh, it's the most horrible 196 00:07:55.020 --> 00:07:55.340 job. 197 00:07:56.540 --> 00:07:57.780 Professor Fred Watson: It is, isn't it? Yeah. 198 00:07:57.780 --> 00:07:59.020 Andrew Dunkley: Especially writing's fun. 199 00:07:59.100 --> 00:07:59.540 Professor Fred Watson: Yeah. 200 00:07:59.540 --> 00:08:01.340 Andrew Dunkley: But then you've got to fix all your blunders 201 00:08:01.340 --> 00:08:04.180 and you don't realise how really hopeless you 202 00:08:04.180 --> 00:08:05.060 are until you have 203 00:08:05.060 --> 00:08:07.420 Professor Fred Watson: to edit your own stuff. 204 00:08:07.580 --> 00:08:10.180 Andrew Dunkley: Yeah, yeah. I'd pay someone, but I can't 205 00:08:10.180 --> 00:08:13.140 afford it. It's not a, it's not a cheap 206 00:08:13.140 --> 00:08:15.800 thing to get Done book editing. Um, 207 00:08:16.040 --> 00:08:18.880 but anyway, uh, so the basic 208 00:08:18.880 --> 00:08:21.200 answer to Clint's question is yes, it's going 209 00:08:21.200 --> 00:08:24.120 to happen. Uh, there will be complete black 210 00:08:24.360 --> 00:08:26.520 nothingness, um, 211 00:08:27.400 --> 00:08:29.600 in a matter of about three weeks time, or 212 00:08:29.600 --> 00:08:31.400 could be three gazillion years time. 213 00:08:31.640 --> 00:08:32.840 Professor Fred Watson: I think the latter's more likely. 214 00:08:32.840 --> 00:08:35.760 Andrew Dunkley: More likely the latter. Thank you, Clint. 215 00:08:35.760 --> 00:08:36.840 Great to hear from you. 216 00:08:37.320 --> 00:08:39.400 Our next question comes from 217 00:08:40.200 --> 00:08:42.120 somebody whose name I forgot to write down. 218 00:08:42.260 --> 00:08:44.640 Uh, no, it didn't. It comes from, uh, Alan. 219 00:08:44.640 --> 00:08:47.080 Now, this is a pretty big question, so I'll 220 00:08:47.080 --> 00:08:48.900 just go straight through it and we can figure 221 00:08:48.900 --> 00:08:51.860 all out the rest out later. Uh, I know you 222 00:08:51.860 --> 00:08:54.660 want audio questions, but you know how they 223 00:08:54.660 --> 00:08:57.420 say you have a face made for radio? I've got 224 00:08:57.420 --> 00:09:00.300 one of those. Well, uh, I have a voice made 225 00:09:00.300 --> 00:09:03.220 for text. That's very 226 00:09:03.220 --> 00:09:05.820 good. I, um, hope it's not true. Uh, I 227 00:09:05.820 --> 00:09:08.100 discovered space nuts more than a year ago 228 00:09:08.260 --> 00:09:10.460 and have listened to your entire back 229 00:09:10.460 --> 00:09:11.140 catalogue. 230 00:09:11.300 --> 00:09:11.780 Professor Fred Watson: Wow. 231 00:09:12.740 --> 00:09:15.700 Andrew Dunkley: Wow. Get a job. No. Fantastic. Thank 232 00:09:15.700 --> 00:09:18.380 you. Uh, still listening and have not lost my 233 00:09:18.380 --> 00:09:19.060 mind yet. 234 00:09:19.360 --> 00:09:19.680 Professor Fred Watson: Wow. 235 00:09:20.000 --> 00:09:20.720 Andrew Dunkley: That's a record. 236 00:09:21.210 --> 00:09:22.920 Uh, here's something that's been bothering me 237 00:09:22.920 --> 00:09:25.520 for, uh, some months. Some physicists 238 00:09:25.600 --> 00:09:28.360 don't believe relativity, uh, when it says 239 00:09:28.360 --> 00:09:30.640 that gravity is not a force. Also, they 240 00:09:30.640 --> 00:09:32.560 believe that all forces are conveyed by 241 00:09:32.560 --> 00:09:35.440 particles. To unify gravity with other 242 00:09:35.440 --> 00:09:38.240 forces, they postulate the graviton to be 243 00:09:38.240 --> 00:09:41.000 that particle for gravity. It's said that 244 00:09:41.000 --> 00:09:42.800 nothing escapes a black hole, but actually 245 00:09:42.800 --> 00:09:45.440 gravity does. If gravitons exist 246 00:09:46.380 --> 00:09:49.100 and convey the force of gravity, then they 247 00:09:49.100 --> 00:09:51.500 escape black holes. So they are not affected 248 00:09:51.500 --> 00:09:54.500 by gravity. That means they do not affect 249 00:09:54.500 --> 00:09:57.100 each other. We know gravity does affect all 250 00:09:57.100 --> 00:09:59.500 massive particles and photons, massless 251 00:09:59.500 --> 00:10:01.779 particles that convey the electromagnetic 252 00:10:01.779 --> 00:10:04.340 force. I don't know if gravitons affect other 253 00:10:04.340 --> 00:10:06.820 massless particles. This is the interesting 254 00:10:06.820 --> 00:10:09.700 part. If f equals gm 1 m 255 00:10:09.700 --> 00:10:12.220 2 divided by d squared is 256 00:10:12.380 --> 00:10:15.140 the complete calculation for the force 257 00:10:15.140 --> 00:10:17.500 of gravity, no modifications introduced by 258 00:10:17.720 --> 00:10:20.040 relativity or quantum physics, then gravitons 259 00:10:20.040 --> 00:10:23.040 are not affected by anything. So gravitons 260 00:10:23.040 --> 00:10:25.880 affect every particle except gravitons and 261 00:10:25.880 --> 00:10:28.760 are not affected by anything. So is 262 00:10:28.760 --> 00:10:30.840 an asymmetry that breaks 263 00:10:32.280 --> 00:10:34.520 conservation, uh, of energy and momentum. My 264 00:10:34.520 --> 00:10:37.480 question is. Here it is. Why do some 265 00:10:37.480 --> 00:10:39.720 physicists still believe in 266 00:10:40.040 --> 00:10:42.600 gravitons? That comes from Alan in San 267 00:10:42.600 --> 00:10:45.000 Antonio, Texas. Boy, Alan, you've put a lot 268 00:10:45.000 --> 00:10:46.840 of thought into that. You really have. 269 00:10:47.000 --> 00:10:49.120 Professor Fred Watson: Yeah. And these are questions that are right 270 00:10:49.120 --> 00:10:51.900 on money as well. Yeah. Uh, especially the 271 00:10:51.900 --> 00:10:54.300 last one. Why do physicists believe in 272 00:10:54.300 --> 00:10:56.100 gravitons? I think most physicists probably 273 00:10:56.100 --> 00:10:58.340 do. Uh, Alan, because 274 00:10:58.560 --> 00:11:01.020 um, we know that gravity is a fundamental 275 00:11:01.020 --> 00:11:03.420 force and all the other fundamental forces 276 00:11:03.420 --> 00:11:05.780 have their subatomic particles, 277 00:11:06.290 --> 00:11:09.060 uh, which are basically 278 00:11:09.930 --> 00:11:12.890 um, um, 279 00:11:13.300 --> 00:11:16.060 particles that can. That sort of what we 280 00:11:16.060 --> 00:11:18.580 call, we call them bosons. They're what, they 281 00:11:18.580 --> 00:11:21.300 carry a field in a way. And the field is 282 00:11:21.920 --> 00:11:24.550 another way of looking at how a uh, 283 00:11:24.680 --> 00:11:27.560 force works. I didn't 284 00:11:27.560 --> 00:11:30.400 phrase that very well, but uh, that's why 285 00:11:30.480 --> 00:11:33.080 some physicists believe in gravitons. We've 286 00:11:33.080 --> 00:11:35.920 never found them. We don't have a particle 287 00:11:35.920 --> 00:11:38.680 physics theory of gravity. Uh, so we don't 288 00:11:38.680 --> 00:11:40.320 know that they exist. But I think most 289 00:11:40.400 --> 00:11:43.040 physicists would assume that they exist. 290 00:11:44.160 --> 00:11:46.880 And so uh, that 291 00:11:46.880 --> 00:11:49.760 first um, conundrum 292 00:11:51.120 --> 00:11:52.640 that you mentioned, 293 00:11:53.840 --> 00:11:56.160 if nothing escapes a black hole, well, 294 00:11:56.160 --> 00:11:58.800 gravity does. And so if 295 00:11:58.800 --> 00:12:00.760 gravitons exist and convey the force of 296 00:12:00.760 --> 00:12:03.000 gravity, then they escape black holes. So 297 00:12:03.000 --> 00:12:05.240 they're not affected by gravity. That means 298 00:12:05.240 --> 00:12:08.240 they do not affect each other. But in 299 00:12:08.240 --> 00:12:10.720 fact, um, uh, 300 00:12:11.200 --> 00:12:14.000 the bottom line with black holes it's 301 00:12:14.000 --> 00:12:16.910 quite complicated. Uh, but you 302 00:12:17.230 --> 00:12:19.870 don't have gravitons escaping 303 00:12:20.510 --> 00:12:22.970 from the black hole. Uh, 304 00:12:23.390 --> 00:12:26.190 the way people who know a lot more about 305 00:12:26.190 --> 00:12:28.510 these things than me, uh, the way they 306 00:12:28.510 --> 00:12:31.390 envisage this is that the gravitational 307 00:12:31.390 --> 00:12:34.230 field of the black hole is a kind 308 00:12:34.230 --> 00:12:37.190 of fossilised one that was 309 00:12:37.190 --> 00:12:39.870 established before the collapse 310 00:12:40.590 --> 00:12:43.280 into uh, a black hole. 311 00:12:44.000 --> 00:12:46.800 Or, and here's another way of looking at it. 312 00:12:49.120 --> 00:12:51.680 This really, you're gonna think, um, Alan, 313 00:12:51.680 --> 00:12:54.120 this is a cop out, but this is the way the 314 00:12:54.120 --> 00:12:57.120 physicists see it. Uh, the, 315 00:12:57.200 --> 00:12:59.280 the gravitational field of black hole 316 00:12:59.600 --> 00:13:02.400 basically uh, includes 317 00:13:02.400 --> 00:13:04.560 something called virtual gravitons. 318 00:13:05.650 --> 00:13:08.320 Uh, and so that sort of ties in with the fact 319 00:13:08.320 --> 00:13:10.800 that the, the gravitational field is a 320 00:13:10.800 --> 00:13:13.080 fossilised footprint, if I can put it that 321 00:13:13.080 --> 00:13:15.940 way. Um, the 322 00:13:16.020 --> 00:13:18.740 virtual gravitons, uh, are an 323 00:13:18.740 --> 00:13:21.380 embodiment of that, but they don't 324 00:13:21.460 --> 00:13:23.900 necessarily obey the 325 00:13:23.900 --> 00:13:25.860 normal laws of physics. 326 00:13:28.020 --> 00:13:28.420 So 327 00:13:30.870 --> 00:13:31.490 uh, 328 00:13:34.100 --> 00:13:36.820 basically what you've got here, and 329 00:13:37.540 --> 00:13:40.250 I think, um, the 330 00:13:40.250 --> 00:13:42.690 physicists who look at this problem probably 331 00:13:42.690 --> 00:13:45.490 just automatically drop into the two 332 00:13:45.490 --> 00:13:48.290 camps of relativist people who 333 00:13:48.290 --> 00:13:51.090 are ah, experts in general relativity. That's 334 00:13:51.090 --> 00:13:53.130 Einstein's theory of gravity that says, yes, 335 00:13:53.470 --> 00:13:56.130 um, gravity is not a force, it's just a 336 00:13:56.130 --> 00:13:58.930 distortion of space. Uh, and the quantum 337 00:13:58.930 --> 00:14:01.730 mechanics people who look at it from the 338 00:14:01.730 --> 00:14:04.490 perspective of gravitons. 339 00:14:05.400 --> 00:14:08.170 Um, and so yeah, the virtual particles, 340 00:14:08.800 --> 00:14:11.770 uh, the quantum mechanics 341 00:14:11.850 --> 00:14:13.930 person's answer to this, 342 00:14:15.180 --> 00:14:17.970 uh, they're basically 343 00:14:17.970 --> 00:14:20.849 just mathematical constructs, uh, in a 344 00:14:20.849 --> 00:14:23.570 quantum field. And so they don't have to 345 00:14:23.570 --> 00:14:26.410 obey speed limits or anything like that, or 346 00:14:26.410 --> 00:14:28.370 even don't have to worry about the event 347 00:14:28.370 --> 00:14:31.050 horizon so they can continually 348 00:14:32.000 --> 00:14:34.840 basically, uh, keep the gravitational force 349 00:14:34.840 --> 00:14:37.600 there without actually being 350 00:14:37.600 --> 00:14:40.480 trapped by it. I think that's the way 351 00:14:40.560 --> 00:14:42.240 physicists look at it. 352 00:14:43.250 --> 00:14:46.000 Andrew Dunkley: Uh, all that says to me is 353 00:14:48.480 --> 00:14:50.440 something. It's still a big mystery. There 354 00:14:50.440 --> 00:14:52.400 are so many different theories behind 355 00:14:52.400 --> 00:14:55.360 gravity, and we really don't know what it is. 356 00:14:56.560 --> 00:14:58.200 We know what it is, but we don't know why it 357 00:14:58.200 --> 00:14:58.480 is. 358 00:14:58.880 --> 00:15:01.640 Professor Fred Watson: Well, no. So all we know about 359 00:15:01.640 --> 00:15:04.470 gravity is the way it behaves. Um, 360 00:15:04.700 --> 00:15:07.500 we really don't know what it is. And in a 361 00:15:07.500 --> 00:15:10.300 way, Alan's question is well posed 362 00:15:10.300 --> 00:15:13.060 because it could end up that it's something 363 00:15:13.060 --> 00:15:14.860 different and there aren't gravitons. 364 00:15:15.650 --> 00:15:18.300 Um, and, uh, that's why we haven't found 365 00:15:18.300 --> 00:15:21.110 them, because they're not there. Um, 366 00:15:22.620 --> 00:15:24.620 it's fascinating. I mean, in a sense, 367 00:15:25.550 --> 00:15:28.180 uh, gravitons are along the same line as the 368 00:15:28.180 --> 00:15:31.020 hypothetical dark matter particles. We know, 369 00:15:31.810 --> 00:15:34.730 um, dark matter is real. We know it's 370 00:15:34.730 --> 00:15:37.370 there. Uh, we assume it's subatomic 371 00:15:37.370 --> 00:15:40.250 particles. We've seen some recent works. Uh, 372 00:15:40.330 --> 00:15:42.810 work. Sorry. We've seen some recent work that 373 00:15:42.810 --> 00:15:45.570 suggests perhaps they're not, um, 374 00:15:45.570 --> 00:15:47.770 perhaps it's not subatomic particles, but 375 00:15:47.770 --> 00:15:49.650 primordial black holes, which can be very 376 00:15:49.650 --> 00:15:52.610 small and very difficult to detect. Uh, which 377 00:15:52.610 --> 00:15:55.210 takes us back to the, um, macho 378 00:15:55.210 --> 00:15:57.530 theory. Massive compact halo objects, the 379 00:15:57.610 --> 00:16:00.330 macho theory of dark matter, as distinct from 380 00:16:00.330 --> 00:16:01.930 the WIMP theory, the weakly interacting 381 00:16:01.930 --> 00:16:04.670 massive particles. I 382 00:16:04.670 --> 00:16:07.190 think gravitons almost fall into the same 383 00:16:07.190 --> 00:16:10.110 boat as dark matter particles in the sense 384 00:16:10.110 --> 00:16:12.630 that we haven't detected them. We hypothesise 385 00:16:12.630 --> 00:16:14.310 that they're there. We've built constructs 386 00:16:14.310 --> 00:16:17.310 like virtual gravitons that allow us to do 387 00:16:17.310 --> 00:16:19.680 that without going completely mad. Um, 388 00:16:19.989 --> 00:16:22.790 but, uh, at the moment, still, I think, 389 00:16:23.110 --> 00:16:25.310 uh, the door is wide open for all kinds of 390 00:16:25.310 --> 00:16:27.470 new ideas that might change our view 391 00:16:27.470 --> 00:16:27.990 completely. 392 00:16:28.470 --> 00:16:31.230 Andrew Dunkley: Yeah, I guess the day we crack it will 393 00:16:31.230 --> 00:16:33.470 go, uh. Yeah, I should have thought of that. 394 00:16:35.070 --> 00:16:37.230 Professor Fred Watson: Exactly. Well, Alan's already thought of it. 395 00:16:37.470 --> 00:16:37.950 Andrew Dunkley: Yeah. 396 00:16:38.270 --> 00:16:40.790 Professor Fred Watson: Yeah. In terms of, you know, what, what the 397 00:16:40.790 --> 00:16:43.110 conundrums are and why it is. Why it's so 398 00:16:43.110 --> 00:16:44.910 difficult. Yeah, it's a great question. 399 00:16:45.070 --> 00:16:47.070 Andrew Dunkley: I guess the question that comes from that is, 400 00:16:47.070 --> 00:16:49.670 does it have to be a particle? And the answer 401 00:16:49.670 --> 00:16:52.390 is no. Um, it doesn't, uh, have to be 402 00:16:52.390 --> 00:16:54.150 just because everything else is made of 403 00:16:54.150 --> 00:16:55.870 particles. So. 404 00:16:56.750 --> 00:16:58.500 Professor Fred Watson: Yes, that's right. I mean, it's. 405 00:16:59.610 --> 00:17:01.530 So what's called the standard model of 406 00:17:01.690 --> 00:17:04.090 subatomic particles is this 407 00:17:04.490 --> 00:17:07.410 group of 17 particles which we don't 408 00:17:07.410 --> 00:17:09.210 think can be broken down into Anything 409 00:17:09.210 --> 00:17:10.410 smaller. That's why they're called 410 00:17:10.410 --> 00:17:13.130 fundamental, um, and 411 00:17:13.210 --> 00:17:15.670 they account. Among them are, uh, 412 00:17:16.970 --> 00:17:19.130 the force, um, particles, 413 00:17:19.910 --> 00:17:22.770 um, electromagnetic, strong 414 00:17:22.770 --> 00:17:24.750 and weak nuclear forces, um, 415 00:17:26.670 --> 00:17:29.580 uh, which we know about. Gravity is just 416 00:17:29.580 --> 00:17:32.460 assumed to be, uh, a fundamental force 417 00:17:32.460 --> 00:17:34.340 with its fundamental particle because it 418 00:17:34.340 --> 00:17:37.220 behaves in every other way. It behaves like 419 00:17:37.220 --> 00:17:39.500 the other ones do. Uh, but we just haven't 420 00:17:39.500 --> 00:17:41.820 managed to pinpoint the particle itself. 421 00:17:43.020 --> 00:17:43.740 There you go. 422 00:17:43.770 --> 00:17:46.740 Andrew Dunkley: Ah, Alan, you've kind of, um, put 423 00:17:46.740 --> 00:17:49.220 your thumb on one of the big mysteries of the 424 00:17:49.220 --> 00:17:52.050 universe and expected us to have an answer. 425 00:17:53.590 --> 00:17:56.370 Uh, no, it's just 426 00:17:56.530 --> 00:17:59.090 one of those great big, um, question marks in 427 00:17:59.090 --> 00:18:00.810 space. If you look up, you can see a giant 428 00:18:00.810 --> 00:18:03.650 question mark in space. That's gravity. 429 00:18:04.770 --> 00:18:06.130 Professor Fred Watson: That's right, yeah. 430 00:18:06.250 --> 00:18:08.970 Andrew Dunkley: Uh, whether or not there are gravitons, the 431 00:18:08.970 --> 00:18:11.690 debate remains. Thank, uh, you, Alan, for the 432 00:18:11.690 --> 00:18:14.210 question. This is Space Nuts Andrew Dunkley 433 00:18:14.210 --> 00:18:16.290 here with Professor Fred Watson Watson. 434 00:18:18.410 --> 00:18:20.290 Professor Fred Watson: I believe that this nation should commit 435 00:18:20.290 --> 00:18:22.490 Andrew Dunkley: itself to achieving the goal 436 00:18:23.130 --> 00:18:26.090 before this decade is out, of landing a 437 00:18:26.090 --> 00:18:26.250 man 438 00:18:26.250 --> 00:18:28.610 Professor Fred Watson: on the moon and returning him safely to the 439 00:18:28.610 --> 00:18:28.930 Earth. 440 00:18:28.930 --> 00:18:30.730 Andrew Dunkley: Beast nuts, Fred Watson. 441 00:18:30.730 --> 00:18:33.590 Our next question comes from, uh, 442 00:18:33.609 --> 00:18:35.770 somebody else who's thinking particles. I 443 00:18:35.770 --> 00:18:38.250 spend a lot of time thinking about 444 00:18:38.570 --> 00:18:41.370 photons and have, uh, so many questions about 445 00:18:41.370 --> 00:18:44.370 them. Uh, you know, I know 446 00:18:44.370 --> 00:18:46.770 this about Misty because, um, she's always 447 00:18:46.770 --> 00:18:48.610 walking around with a light bulb above her 448 00:18:48.610 --> 00:18:50.790 head. So that explains that, 449 00:18:51.210 --> 00:18:53.670 um, photons are really weird to understand. 450 00:18:54.470 --> 00:18:56.790 I'm curious to know if there are any 451 00:18:56.790 --> 00:18:59.590 fundamental particles that do not have a 452 00:18:59.590 --> 00:19:02.550 wave function. And then is it possible 453 00:19:02.550 --> 00:19:05.350 to detect a particle or photon that does not 454 00:19:05.350 --> 00:19:08.070 have any properties of a wave? 455 00:19:08.790 --> 00:19:10.750 And the last part of the question. Is it 456 00:19:10.750 --> 00:19:13.030 possible for a photon or particle to have 457 00:19:13.030 --> 00:19:15.310 such a long wavelength that we don't have a 458 00:19:15.310 --> 00:19:17.650 detector big enough to pick it up? That's, 459 00:19:17.650 --> 00:19:19.630 uh, from Misty in Pennsylvania, one of our 460 00:19:19.630 --> 00:19:21.970 administrators on the Facebook PODC Ask 461 00:19:21.970 --> 00:19:24.970 Group. So, um, uh, thank you, Misty, 462 00:19:24.970 --> 00:19:26.570 for sending in a question. Nice to hear from 463 00:19:26.570 --> 00:19:28.690 you and beautiful part of the world, 464 00:19:28.690 --> 00:19:30.970 Pennsylvania. Got to drive through that last 465 00:19:30.970 --> 00:19:33.890 year. And, uh, yeah, it is 466 00:19:33.890 --> 00:19:36.850 absolutely lovely in summer. Don't 467 00:19:36.850 --> 00:19:38.130 think I want to be there in winter. 468 00:19:41.250 --> 00:19:44.000 Nevertheless. Okay, so, um, 469 00:19:44.770 --> 00:19:47.770 photons. Yeah. What can we talk? What 470 00:19:47.770 --> 00:19:50.610 can you tell us about? Are there any 471 00:19:50.610 --> 00:19:52.410 particles that don't have wavelengths? That's 472 00:19:52.410 --> 00:19:53.790 an interest question. 473 00:19:53.790 --> 00:19:56.710 Professor Fred Watson: Yes. So that's M, more or less what 474 00:19:56.710 --> 00:19:59.230 it amounts to. So we see 475 00:19:59.470 --> 00:20:01.790 in quantum mechanics, uh, 476 00:20:02.190 --> 00:20:04.910 we see this fundamental thing that particles, 477 00:20:05.670 --> 00:20:08.590 m, uh, display the properties 478 00:20:08.590 --> 00:20:11.510 both of a particle and a wave. And so we 479 00:20:11.510 --> 00:20:14.350 call it a wave function. And as 480 00:20:14.350 --> 00:20:16.950 I understand it, and I Think, uh, quantum 481 00:20:16.950 --> 00:20:19.310 mechanics backs, uh, this up. 482 00:20:19.910 --> 00:20:22.860 Uh, there are no fundamental particles 483 00:20:23.020 --> 00:20:26.020 that don't have a wave function, so they 484 00:20:26.020 --> 00:20:28.860 all exhibit this wave particle 485 00:20:28.940 --> 00:20:29.660 duality. 486 00:20:30.570 --> 00:20:30.600 Andrew Dunkley: Um, 487 00:20:35.900 --> 00:20:36.960 Professor Fred Watson: It is, uh, 488 00:20:38.940 --> 00:20:41.100 I guess, you know, the way that, 489 00:20:41.150 --> 00:20:43.900 um, particle physicists think about 490 00:20:43.900 --> 00:20:46.780 these things are uh, a little bit different 491 00:20:47.610 --> 00:20:50.530 from the way we might interpret it. So when I 492 00:20:50.530 --> 00:20:52.890 think of the wave particle duality, 493 00:20:53.450 --> 00:20:55.850 my mind immediately goes to the photon, 494 00:20:56.550 --> 00:20:59.450 um, which, um, Misty's already mentioned. 495 00:21:00.030 --> 00:21:02.170 Uh, yes, we understand 496 00:21:03.210 --> 00:21:05.770 photons as particles because we see the 497 00:21:05.770 --> 00:21:08.530 photoelectric effect, which insists that 498 00:21:08.530 --> 00:21:10.330 they've got to be particles because you get 499 00:21:10.490 --> 00:21:13.010 basically quantized amounts of energy out of 500 00:21:13.010 --> 00:21:15.850 them. But then when I think about the waves, 501 00:21:15.930 --> 00:21:18.570 I think about things like polarisation, 502 00:21:19.130 --> 00:21:21.350 uh, where you've got waves that are 503 00:21:21.590 --> 00:21:23.270 oscillating in different directions. I think 504 00:21:23.270 --> 00:21:24.790 we talked about that a couple of episodes 505 00:21:24.790 --> 00:21:27.390 ago, we did, in the mapping of the magnetic 506 00:21:27.390 --> 00:21:30.350 fields of the galaxy of the universe. Um, and 507 00:21:30.350 --> 00:21:32.750 so I always think about waves vibrating 508 00:21:32.750 --> 00:21:34.710 through a median. But, 509 00:21:35.010 --> 00:21:37.910 um, the physicists 510 00:21:38.710 --> 00:21:41.350 kind of combine those two ideas 511 00:21:42.790 --> 00:21:45.590 and, uh, think in terms of, uh, something 512 00:21:45.990 --> 00:21:48.310 it's usually called quantized 513 00:21:48.470 --> 00:21:50.630 excitations of underlying 514 00:21:51.010 --> 00:21:53.090 fields. So 515 00:21:53.570 --> 00:21:56.510 that's to say that, um, 516 00:21:56.610 --> 00:21:59.490 it kind of mixes both relativity and 517 00:21:59.890 --> 00:22:02.610 quantum physics here because the 518 00:22:02.610 --> 00:22:04.850 underlying field is what? 519 00:22:05.530 --> 00:22:08.290 Um, it's the sort of, 520 00:22:08.370 --> 00:22:10.090 if I can put it that way, the background 521 00:22:10.090 --> 00:22:13.010 canvas on which the information 522 00:22:13.330 --> 00:22:16.050 is superimposed and the particle 523 00:22:16.450 --> 00:22:19.170 is a bit of that background canvas that is 524 00:22:19.250 --> 00:22:22.090 excited to vibrate and 525 00:22:22.170 --> 00:22:24.770 give you a wave, but it's 526 00:22:24.770 --> 00:22:27.370 excited in a way that is quantized. That 527 00:22:27.370 --> 00:22:30.210 means there isn't an 528 00:22:30.210 --> 00:22:33.210 infinite number of different excitations 529 00:22:33.290 --> 00:22:34.890 that can be set up. 530 00:22:36.570 --> 00:22:39.450 They're specific numbers, 531 00:22:39.450 --> 00:22:41.770 which means you get specific wavelengths 532 00:22:42.090 --> 00:22:44.930 from the excitation. So it is all a 533 00:22:44.930 --> 00:22:46.660 mix of, of 534 00:22:47.460 --> 00:22:50.340 particles and waves, but it kind of brings 535 00:22:50.340 --> 00:22:52.940 it together and once you think of it in those 536 00:22:52.940 --> 00:22:54.820 terms, uh, then 537 00:22:56.100 --> 00:22:58.140 it becomes clear that you can't have a 538 00:22:58.140 --> 00:23:00.580 particle without its wave function. 539 00:23:00.980 --> 00:23:03.380 Andrew Dunkley: Which kind of writes off her second question. 540 00:23:03.380 --> 00:23:06.140 If there's, um, a long enough wavelength that 541 00:23:06.140 --> 00:23:07.940 we haven't got the equipment to detect it. 542 00:23:08.450 --> 00:23:10.260 Professor Fred Watson: Um, no, I don't think it does 543 00:23:11.380 --> 00:23:13.910 because I think, um, 544 00:23:14.970 --> 00:23:17.970 I mean we, you know, we. In, in 545 00:23:17.970 --> 00:23:20.410 a way the ultra low 546 00:23:20.410 --> 00:23:23.050 frequency radio waves are a bit like that, 547 00:23:23.730 --> 00:23:26.090 uh, because they are, 548 00:23:27.210 --> 00:23:29.009 uh. Some of them have got a wavelength bigger 549 00:23:29.009 --> 00:23:31.890 than the Earth. And 550 00:23:31.890 --> 00:23:34.050 so how do you detect that? Well, you've got 551 00:23:34.050 --> 00:23:36.090 to have a spacecraft that's got the other end 552 00:23:36.090 --> 00:23:38.850 of the aerial on it, you know, that sort of 553 00:23:38.850 --> 00:23:41.130 thing. Um, there's also, 554 00:23:42.530 --> 00:23:45.450 uh. What was I going to say, 555 00:23:45.630 --> 00:23:48.290 um, yeah, we know that there are 556 00:23:48.290 --> 00:23:50.970 gravitational waves that have got 557 00:23:51.290 --> 00:23:54.080 wavelengths measured in light years. Uh, 558 00:23:54.410 --> 00:23:56.650 I think the gravitational 559 00:23:57.690 --> 00:24:00.450 properties of the Big Bang. So the 560 00:24:00.450 --> 00:24:02.290 gravitational waves that were set up by the 561 00:24:02.290 --> 00:24:05.210 Big Bang are extremely long 562 00:24:05.290 --> 00:24:07.370 wavelength. I think I've got that the right 563 00:24:07.370 --> 00:24:10.000 way around. Um, 564 00:24:10.080 --> 00:24:12.840 it's so, uh. And we, you know, there are 565 00:24:12.840 --> 00:24:15.760 ones that we don't have normal, 566 00:24:16.160 --> 00:24:18.720 everyday ways of detecting them. There are 567 00:24:18.720 --> 00:24:20.520 subtleties because you expect some of these 568 00:24:20.520 --> 00:24:22.720 waves to be polarised. And that, I think, 569 00:24:22.720 --> 00:24:24.999 gives you an insight into it. But, yeah, 570 00:24:24.999 --> 00:24:27.920 it's, uh. Look, it is a good question. 571 00:24:28.600 --> 00:24:31.400 Uh, and I, uh, think, um, once again, 572 00:24:31.400 --> 00:24:34.360 mist is thinking outside the box. Uh, 573 00:24:34.360 --> 00:24:36.960 no particles without their wave 574 00:24:36.960 --> 00:24:39.480 function, because a particle is an 575 00:24:39.480 --> 00:24:42.260 excitation of the underlying field, a 576 00:24:42.260 --> 00:24:44.540 quantized excitation of the underlying field. 577 00:24:45.020 --> 00:24:47.740 Andrew Dunkley: So it is possible we cannot detect certain 578 00:24:47.740 --> 00:24:49.620 wavelengths because they're too big, but they 579 00:24:49.620 --> 00:24:50.300 still exist. 580 00:24:50.540 --> 00:24:51.780 Professor Fred Watson: I think that's right, yes. 581 00:24:51.780 --> 00:24:54.060 Andrew Dunkley: Yeah. All right. What about gravitons? Do you 582 00:24:54.060 --> 00:24:55.380 reckon they have a wavelength? 583 00:24:55.380 --> 00:24:57.700 Professor Fred Watson: Well, yes, they do. That's the thing. Um, if 584 00:24:57.700 --> 00:24:59.630 they exist, yes. Uh, because, um, 585 00:25:01.030 --> 00:25:03.980 uh, we've got gravitational waves. So the 586 00:25:03.980 --> 00:25:06.100 wave particle duality works both ways. If 587 00:25:06.100 --> 00:25:07.580 you've got a wave, you've got a particle. 588 00:25:07.900 --> 00:25:10.780 Andrew Dunkley: There you go. Uh, good one. Thanks, 589 00:25:10.780 --> 00:25:13.220 Misty. Hope all is well in Pennsylvania. 590 00:25:16.100 --> 00:25:18.420 Three, two, one. 591 00:25:18.980 --> 00:25:20.260 Professor Fred Watson: Space nuts. 592 00:25:20.500 --> 00:25:23.380 Andrew Dunkley: And our final question, uh, comes from 593 00:25:23.380 --> 00:25:25.380 another one of our regular contributors, 594 00:25:25.380 --> 00:25:28.140 Casey in Colorado. What does it feel 595 00:25:28.140 --> 00:25:30.740 like to go from weightlessness to normal 596 00:25:30.740 --> 00:25:33.060 gravity for astronauts when returning to 597 00:25:33.060 --> 00:25:36.030 Earth? I think it would depend 598 00:25:36.030 --> 00:25:38.940 on how long you've been up there and, uh, 599 00:25:38.940 --> 00:25:40.470 whether or not you've actually bothered to 600 00:25:40.470 --> 00:25:41.470 use the treadmill. 601 00:25:43.230 --> 00:25:45.030 Professor Fred Watson: Well, that's right. The treadmill is all 602 00:25:45.030 --> 00:25:46.750 about keeping up your muscle strength. 603 00:25:46.910 --> 00:25:49.070 Andrew Dunkley: Exactly. Um, because once you're out there, 604 00:25:49.310 --> 00:25:51.900 your muscles immediately start to wither. Uh, 605 00:25:52.390 --> 00:25:52.910 they do. 606 00:25:52.910 --> 00:25:55.390 Professor Fred Watson: And you don't really have anything against 607 00:25:55.390 --> 00:25:58.230 which to push to keep them, 608 00:25:58.230 --> 00:26:00.060 you know, keep them going, other than the. 609 00:26:00.530 --> 00:26:02.450 The, um, torture equipment that 610 00:26:03.490 --> 00:26:06.010 NASA and Roscosmos provide on their space 611 00:26:06.010 --> 00:26:06.530 station. 612 00:26:06.530 --> 00:26:08.890 Andrew Dunkley: I think on Space Lab, they didn't have a 613 00:26:08.890 --> 00:26:10.850 treadmill. They had a running track that ran 614 00:26:10.850 --> 00:26:13.810 around the inside of 615 00:26:14.850 --> 00:26:17.850 wall of, uh, Skylab, I think. And 616 00:26:17.850 --> 00:26:20.690 so I've seen footage of astronauts actually 617 00:26:20.690 --> 00:26:23.090 running in a circle around the 618 00:26:23.410 --> 00:26:25.250 interior of Skylab. 619 00:26:25.570 --> 00:26:28.250 Professor Fred Watson: So they're keeping themselves, um, running 620 00:26:28.250 --> 00:26:30.290 just by the centrifugal force that they're 621 00:26:30.370 --> 00:26:32.990 setting up. Yeah, yeah, yeah. That's 622 00:26:32.990 --> 00:26:34.570 interesting. I didn't know that. That's, uh. 623 00:26:34.630 --> 00:26:37.270 Andrew Dunkley: Yeah, I'm sure that if you had online, you'd 624 00:26:37.270 --> 00:26:40.030 find Footage of it. I. I strongly remember 625 00:26:40.030 --> 00:26:42.430 that M. I saw it on the news one day and 626 00:26:42.430 --> 00:26:44.510 thought, wow, how did they do that? Well, 627 00:26:44.510 --> 00:26:45.620 there's no gravity, duh. Uh, 628 00:26:47.470 --> 00:26:49.230 Professor Fred Watson: yeah. Um, 629 00:26:50.350 --> 00:26:53.350 wasn't there something like that in 2001 A 630 00:26:53.350 --> 00:26:55.070 Space Odyssey? I think there was. Could have 631 00:26:55.070 --> 00:26:55.270 been. 632 00:26:55.270 --> 00:26:58.030 Andrew Dunkley: I think I watched that very recently. 633 00:26:58.110 --> 00:27:00.150 I just thought I really wanted to watch it 634 00:27:00.150 --> 00:27:02.500 again. But, um, I fell asleep. But 635 00:27:02.980 --> 00:27:04.860 it's very late. Judy had gone to bed, and I 636 00:27:04.860 --> 00:27:07.730 thought, oh, I might just start this. Uh, 637 00:27:07.730 --> 00:27:08.900 yeah, I was gone. 638 00:27:11.420 --> 00:27:13.860 Um, what was the question? Oh, uh, what's the 639 00:27:13.940 --> 00:27:16.620 feel like? I also remember seeing 640 00:27:16.620 --> 00:27:19.460 footage of cosmonauts, uh, coming back 641 00:27:19.460 --> 00:27:22.180 from very long haul time in space. 642 00:27:23.220 --> 00:27:25.580 And they'd get them out of the capsule once 643 00:27:25.580 --> 00:27:27.420 they came back to Earth and they couldn't 644 00:27:27.420 --> 00:27:27.820 stand up. 645 00:27:27.820 --> 00:27:29.740 Professor Fred Watson: Couldn't stand up. Yeah. I've seen similar 646 00:27:29.740 --> 00:27:32.740 things and. Well, you know, even with the 647 00:27:32.740 --> 00:27:34.960 exercise that the Artemis II crew 648 00:27:35.520 --> 00:27:38.240 were doing, they were a little bit wobbly 649 00:27:38.320 --> 00:27:40.920 when they got out of the spacecraft. And we 650 00:27:40.920 --> 00:27:43.920 all saw them going across the deck of the, 651 00:27:44.280 --> 00:27:46.820 uh, recovery ship. Uh, 652 00:27:47.280 --> 00:27:49.239 so I think how wobbly you are probably 653 00:27:49.239 --> 00:27:51.120 depends on just how much effort you've put 654 00:27:51.120 --> 00:27:53.720 into keeping up your muscle strength. So I 655 00:27:53.720 --> 00:27:56.480 think that's the key thing that Casey 656 00:27:57.360 --> 00:28:00.280 might be thinking of. Um, exactly. As 657 00:28:00.280 --> 00:28:02.600 you've said, your muscles go to waste very 658 00:28:02.600 --> 00:28:05.100 quickly. Uh, and if you. You don't 659 00:28:05.100 --> 00:28:06.740 exercise, then you're going to be in big 660 00:28:06.740 --> 00:28:08.780 trouble. You simply would not be able to 661 00:28:08.780 --> 00:28:11.700 walk. Um, so quite a 662 00:28:11.700 --> 00:28:14.140 significant, uh, thing. Ah. Which would also, 663 00:28:14.140 --> 00:28:16.180 of course, depend on how long you've been in 664 00:28:16.180 --> 00:28:17.580 space, how long you've been weightless. 665 00:28:17.820 --> 00:28:20.259 Andrew Dunkley: And the other thing they might suffer from is 666 00:28:20.259 --> 00:28:23.100 fatigue because they have 667 00:28:23.100 --> 00:28:26.060 to work so much harder to achieve the same 668 00:28:26.940 --> 00:28:29.180 mobility as they were used to. When they had 669 00:28:29.180 --> 00:28:32.120 full muscle strength, they'd get 670 00:28:32.120 --> 00:28:34.600 very tired very fast. I think, 671 00:28:35.560 --> 00:28:37.560 all jokes aside, I think the, 672 00:28:38.130 --> 00:28:39.880 um, everyday person, 673 00:28:41.300 --> 00:28:43.340 uh, who's been through, um, 674 00:28:43.480 --> 00:28:46.200 immunotherapy or some 675 00:28:46.200 --> 00:28:49.120 form of, um, um, um, 676 00:28:49.400 --> 00:28:51.620 inhibitor for, um, 677 00:28:53.080 --> 00:28:56.080 testosterone, for example, for cancer 678 00:28:56.080 --> 00:28:58.990 treatment or something like that, that 679 00:28:58.990 --> 00:29:01.110 has the same effect on your muscles. Muscle 680 00:29:01.110 --> 00:29:03.550 wastage. When you stop producing testosterone 681 00:29:04.510 --> 00:29:06.590 as a male, your muscles 682 00:29:07.550 --> 00:29:09.350 actually do fade away. And you've got to do 683 00:29:09.350 --> 00:29:12.270 exercise to keep. Like astronauts, you've got 684 00:29:12.270 --> 00:29:14.190 to keep your exercise up to keep your muscles 685 00:29:14.190 --> 00:29:17.070 in trim, but it 686 00:29:17.070 --> 00:29:20.030 does slow you down. Um, and case in 687 00:29:20.030 --> 00:29:22.230 point, I did have that sort of treatment for 688 00:29:22.230 --> 00:29:24.590 my prostate cancer. And for six months 689 00:29:25.660 --> 00:29:28.180 I went into basically the 690 00:29:28.180 --> 00:29:30.460 equivalent to menopause. I had muscle 691 00:29:30.460 --> 00:29:32.980 wastage. Um, I kept up my 692 00:29:32.980 --> 00:29:35.740 exercise, but it wasn't enough. And I 693 00:29:35.980 --> 00:29:38.060 had a situation where I'd go out and play 694 00:29:38.060 --> 00:29:40.899 golf. I lost 40 yards on 695 00:29:40.899 --> 00:29:43.460 shots simply because my muscles had wasted 696 00:29:43.460 --> 00:29:46.180 away. And it's probably taken a year to get 697 00:29:46.180 --> 00:29:46.780 it all back. 698 00:29:47.100 --> 00:29:47.740 Professor Fred Watson: Yeah, interesting. 699 00:29:48.620 --> 00:29:51.580 Andrew Dunkley: Yeah. Um, it would be the same effect for an 700 00:29:51.580 --> 00:29:53.780 astronaut on it. Exactly the same. Different, 701 00:29:53.860 --> 00:29:56.100 different, you know, different mechanism. 702 00:29:56.180 --> 00:29:58.100 Mechanism, but same effect. 703 00:29:59.010 --> 00:30:01.900 Um, and. And yet the 704 00:30:01.900 --> 00:30:03.500 other thing that they'd probably have to deal 705 00:30:03.500 --> 00:30:05.140 with is some, some of them have very 706 00:30:05.700 --> 00:30:08.660 significant health effects from, from 707 00:30:08.660 --> 00:30:10.700 being in zero G and you come back to Earth. 708 00:30:10.700 --> 00:30:13.620 Like we had a, um, didn't. Wasn't there an 709 00:30:13.620 --> 00:30:15.700 astronaut recently who was temporarily 710 00:30:15.700 --> 00:30:18.500 blinded from, 711 00:30:18.500 --> 00:30:21.260 from zero G? And there's all sorts of 712 00:30:21.260 --> 00:30:24.260 things that um, they can suffer from. And 713 00:30:24.660 --> 00:30:26.140 a lot of the time when they come back to 714 00:30:26.140 --> 00:30:28.540 Earth, it does fix itself because you're back 715 00:30:28.540 --> 00:30:31.340 in your normal environment. But when you're 716 00:30:31.340 --> 00:30:33.420 out there orbiting or going to the moon and 717 00:30:33.420 --> 00:30:36.100 back, it is not a human environment. 718 00:30:36.980 --> 00:30:39.500 Professor Fred Watson: That's not normal. Yeah, so it was an 719 00:30:39.500 --> 00:30:42.100 evacuation the uh, beginning of the year, I 720 00:30:42.100 --> 00:30:44.060 think it was, that we only really found out a 721 00:30:44.060 --> 00:30:46.900 few snippets about not very long ago. 722 00:30:47.780 --> 00:30:49.700 And I can't remember what the details were 723 00:30:50.260 --> 00:30:52.480 because my brain's atrophy because of 724 00:30:54.720 --> 00:30:55.440 old age. 725 00:30:56.320 --> 00:30:59.320 Andrew Dunkley: Yes, indeed. But, uh, there 726 00:30:59.320 --> 00:31:02.030 would be various levels of, um, 727 00:31:02.030 --> 00:31:04.320 dysfunction as a consequence of spending time 728 00:31:04.320 --> 00:31:07.280 in space. It would be a 729 00:31:07.840 --> 00:31:10.480 person to person variable. 730 00:31:10.790 --> 00:31:13.480 Um, it's not a one size 731 00:31:13.480 --> 00:31:15.800 fits all situation. Some people who'd come 732 00:31:15.800 --> 00:31:18.600 back probably not feel anything. But if, um, 733 00:31:18.800 --> 00:31:20.840 if you're up there long enough. Yeah, it's 734 00:31:20.840 --> 00:31:22.400 going to have a big impact on you. 735 00:31:22.400 --> 00:31:23.440 Professor Fred Watson: Yes, indeed. 736 00:31:24.240 --> 00:31:26.400 Andrew Dunkley: Thank you so much for the question, Kasey. I 737 00:31:26.400 --> 00:31:29.120 hope we covered it 738 00:31:29.360 --> 00:31:32.240 reasonably well. Um, anyway, 739 00:31:32.290 --> 00:31:34.960 uh, in the not too distant future, I'm pretty 740 00:31:34.960 --> 00:31:36.600 sure there'll be so many people going in and 741 00:31:36.600 --> 00:31:38.600 out of space, they'll come up with ways of 742 00:31:38.600 --> 00:31:41.520 dealing with it. Who knows? And 743 00:31:41.520 --> 00:31:42.960 I think that brings us to the end. 744 00:31:42.960 --> 00:31:44.720 Don't forget, if you've got, uh, questions 745 00:31:44.720 --> 00:31:47.360 for us or observations or comments or 746 00:31:47.360 --> 00:31:49.200 whatever you like, you can go to our website, 747 00:31:49.820 --> 00:31:51.940 send it to us in a text or audio 748 00:31:51.940 --> 00:31:53.344 format@spacenuts 749 00:31:53.656 --> 00:31:55.300 IO or 750 00:31:55.300 --> 00:31:58.060 spacenutspodcast.com 751 00:31:58.460 --> 00:32:01.220 and just click on the little ama button at 752 00:32:01.220 --> 00:32:04.060 the top that stands for Ask me Anything. And 753 00:32:04.930 --> 00:32:07.420 um, you can send it through. Don't forget to 754 00:32:07.500 --> 00:32:09.980 tell us who you are or where you're from. 755 00:32:11.420 --> 00:32:13.140 And Fred Watson, that's it. Thanks so much 756 00:32:13.140 --> 00:32:15.500 for answering those. That was a tough batch 757 00:32:15.500 --> 00:32:15.820 today. 758 00:32:17.500 --> 00:32:19.380 Professor Fred Watson: Great questions though. Well done. To all our 759 00:32:19.380 --> 00:32:22.200 listeners for what they do in terms 760 00:32:22.200 --> 00:32:24.520 of, uh, thinking through a lot of these 761 00:32:24.520 --> 00:32:25.480 issues. It's great. 762 00:32:25.960 --> 00:32:27.520 Andrew Dunkley: Very good. All right, we'll catch you real 763 00:32:27.520 --> 00:32:28.640 soon. Fred Watson, thanks so much. 764 00:32:28.640 --> 00:32:30.040 Professor Fred Watson: Looking forward to it. Thanks, Andrew. 765 00:32:30.200 --> 00:32:32.000 Andrew Dunkley: Professor Fred Watson Watson, astronomer at 766 00:32:32.000 --> 00:32:34.240 large. And thanks to Huw in the studio, who 767 00:32:34.240 --> 00:32:35.980 couldn't be with us today because, um, 768 00:32:36.920 --> 00:32:39.560 there was, um, so much going on with 769 00:32:39.560 --> 00:32:41.960 gravitons and weightlessness, he just 770 00:32:42.360 --> 00:32:45.120 decided to float away. And from me, 771 00:32:45.120 --> 00:32:46.440 Andrew Dunkley. Thanks for your company. 772 00:32:46.440 --> 00:32:47.840 We'll catch you on the next episode of 773 00:32:47.840 --> 00:32:48.710 SpaceNuts real soon. 774 00:32:48.860 --> 00:32:49.020 Professor Fred Watson: Soon. 775 00:32:49.020 --> 00:32:51.940 Andrew Dunkley: Bye. Bye. You've been listening 776 00:32:51.940 --> 00:32:53.660 to the Space Nuts podcast, 777 00:32:55.260 --> 00:32:58.060 available at Apple Podcasts, Spotify, 778 00:32:58.220 --> 00:33:00.980 iHeartRadio or your favourite podcast 779 00:33:00.980 --> 00:33:02.700 player. You can also stream on 780 00:33:02.700 --> 00:33:04.380 demand@bytes.com. 781 00:33:04.700 --> 00:33:06.780 Professor Fred Watson: this has been another quality podcast 782 00:33:06.780 --> 00:33:08.860 production from bytes.com.