WEBVTT 1 00:00:00.280 --> 00:00:01.960 Hi there, Thanks for joining us on a Q and 2 00:00:02.000 --> 00:00:05.559 a edition of Space Nuts. Andrew Dunpley here. Hope you're well. 3 00:00:05.599 --> 00:00:07.599 I hope you can stick around a while because we've 4 00:00:07.599 --> 00:00:10.960 got questions from all over the world and they will 5 00:00:11.000 --> 00:00:15.519 be focusing on gravitational waves, an interesting question about how 6 00:00:15.519 --> 00:00:19.519 they behave or do they behave in certain ways. We're 7 00:00:19.519 --> 00:00:23.000 going to talk orbiting space stations and super constellations, which 8 00:00:23.039 --> 00:00:26.559 is certainly an issue around the planet at the moment. 9 00:00:28.280 --> 00:00:32.399 An observation, I suppose with a question as the kicker 10 00:00:32.520 --> 00:00:37.280 about dark energy and ultra mass black holes and noncompatible 11 00:00:37.399 --> 00:00:40.960 spacesuits has been brought up again. We'll talk about all 12 00:00:41.000 --> 00:00:44.000 of that on this edition of Space Nuts. 13 00:00:44.280 --> 00:00:51.679 Fifteen second to the Channel ten nine ignition Space Nuts 14 00:00:52.560 --> 00:00:54.200 or three two. 15 00:00:56.759 --> 00:01:01.240 Space Nuts. As when I report it, Mel Good, he's back. 16 00:01:01.439 --> 00:01:03.119 I don't know why he keeps coming back, but he's 17 00:01:03.200 --> 00:01:05.599 back again. It's Professor Fred. What's an hello? 18 00:01:05.799 --> 00:01:06.079 Fred? 19 00:01:07.480 --> 00:01:09.319 I'm only back because I can't actually get out of 20 00:01:09.359 --> 00:01:11.280 this room. I'm just locked in here all the time. 21 00:01:11.560 --> 00:01:15.439 So yeah, I mean, I tell you you're never left. 22 00:01:16.239 --> 00:01:19.319 No, it's the Tardis effect. 23 00:01:21.519 --> 00:01:23.799 Shall we get straight into it and answer some questions. 24 00:01:24.319 --> 00:01:27.879 I think we should yes, or at least pretend to. Okay, 25 00:01:29.079 --> 00:01:31.640 this first question comes from Colin. I'm not sure where 26 00:01:31.680 --> 00:01:35.640 Colin is, but he asks, is there any evidence that 27 00:01:35.760 --> 00:01:41.359 gravitational waves reflect and or refract like pressure or light waves. 28 00:01:42.239 --> 00:01:45.879 I know we've talked about gravitational waves a lot, but 29 00:01:46.159 --> 00:01:49.079 I don't know if we've really analyzed this particular aspect 30 00:01:49.120 --> 00:01:50.920 of their behavior, if it exists at all. 31 00:01:52.879 --> 00:01:56.879 We haven't. And it's a good question because we you know, 32 00:01:57.040 --> 00:02:03.159 we know that lightweight which are transverse waves, so like 33 00:02:03.480 --> 00:02:08.960 things are vibrating kind of horizontally or vertically, they are 34 00:02:09.280 --> 00:02:13.360 refracted and reflected. And sound waves are too, which are 35 00:02:13.400 --> 00:02:18.680 pressure waves. They are longitudinal waves changes in pressure. Now, 36 00:02:19.039 --> 00:02:23.479 gravitational waves are neither of those things. They are quadruple waves, 37 00:02:24.000 --> 00:02:27.479 which means that space is sort of distorting in a 38 00:02:28.000 --> 00:02:34.520 peculiar way when they travel through. But here's the crunch, Andrew, 39 00:02:35.639 --> 00:02:39.120 And there's Jordy agreeing with me, which probably means that 40 00:02:39.479 --> 00:02:41.599 on his back. So you'll go berserk in a minute. 41 00:02:41.680 --> 00:02:46.439 But that's all right. Here's the crunch. How do you 42 00:02:47.000 --> 00:02:50.759 so think about refraction? This is the bending of light 43 00:02:52.000 --> 00:02:55.240 when light passes into for example, a piece of glass. 44 00:02:56.199 --> 00:03:01.039 Why does light refract in a piece of glass? Why 45 00:03:01.120 --> 00:03:04.199 does its angle change? And it's because the speed of 46 00:03:04.319 --> 00:03:07.439 light in a piece of glass is lower than it 47 00:03:07.639 --> 00:03:12.280 is in free air or a vacuum, and so the 48 00:03:12.400 --> 00:03:16.439 light waves are slowed down when they pass into the glass, 49 00:03:16.919 --> 00:03:24.520 and that produces the bending phenomena refraction. Now, gravitational waves 50 00:03:25.319 --> 00:03:29.199 are not like that. They always travel at the speed 51 00:03:29.280 --> 00:03:33.400 of light, so they're not refracted in the same way 52 00:03:33.719 --> 00:03:37.280 that we would imagine light being refracted. That phenomenon doesn't 53 00:03:37.479 --> 00:03:46.879 exist for gravitational waves. What does exist, though, is we 54 00:03:47.080 --> 00:03:52.159 know that space time is distorted by matter that comes 55 00:03:52.199 --> 00:03:57.639 from Einstein's general theory of relativity, and space time is distorted, 56 00:03:57.800 --> 00:04:01.919 but light wants to follow the distortion. In other words, 57 00:04:02.000 --> 00:04:06.560 the light doesn't know that it's going through distorted space time, 58 00:04:07.560 --> 00:04:10.280 and so it just follows the distortion. And that's why 59 00:04:10.360 --> 00:04:15.120 we see gravitational lenses. Because the space time around at 60 00:04:15.199 --> 00:04:18.279 cluster of galaxies is distorted. The light just goes on 61 00:04:18.399 --> 00:04:22.959 its merry way at the same speed, and it's not refraction. 62 00:04:23.199 --> 00:04:28.079 It's gravitational lensing. It's bending by gravity, and gravitational waves 63 00:04:28.199 --> 00:04:30.839 behave in the same way. So they do bend, but 64 00:04:31.000 --> 00:04:35.000 it's not through refraction, it's through gravitational distortion of space. 65 00:04:36.720 --> 00:04:42.519 Work that one, now, so that means gravitational waves just 66 00:04:42.800 --> 00:04:43.560 keep going. 67 00:04:44.480 --> 00:04:48.120 They're going what they think is a straight line, but 68 00:04:48.319 --> 00:04:51.240 the straight line isn't straight because it's because the space 69 00:04:51.360 --> 00:04:56.600 is distorted by it. They're called geodesics. It's it's basically 70 00:04:56.720 --> 00:04:59.720 how so that's the way we believe orbits work in 71 00:05:00.279 --> 00:05:04.040 in relativity. You know, if you've got a planet that's 72 00:05:05.639 --> 00:05:07.959 got something in orbit around it, the planet produces a 73 00:05:08.040 --> 00:05:11.040 well of gravity. You can think of it as a 74 00:05:11.120 --> 00:05:15.959 trampoline distorted, and an object basically thinks it's going in 75 00:05:16.000 --> 00:05:18.800 a straight line through that distorted space, but actually it's 76 00:05:18.879 --> 00:05:22.560 going around in a circle in an orbit. That's sort 77 00:05:22.600 --> 00:05:24.519 of and the same thing kind of happens to both 78 00:05:24.600 --> 00:05:28.920 light waves and gravitational waves. They think they're going along 79 00:05:28.959 --> 00:05:30.920 the straight line, but they're not because the straight line 80 00:05:30.959 --> 00:05:34.399 is bent by gravitational pool. I'm not explaining this very well. 81 00:05:34.439 --> 00:05:37.600 I can see that. I can see by the expression 82 00:05:37.639 --> 00:05:40.000 on your face that you think it's lost it altogether. 83 00:05:40.040 --> 00:05:41.600 I have no idea what it's still about. 84 00:05:42.199 --> 00:05:44.439 What kind of bent my mind out of shape. Is 85 00:05:44.519 --> 00:05:46.959 I expected you to say the opposite. I expect you 86 00:05:47.040 --> 00:05:50.480 to say, now, gravitational waves. There are power under themselves, 87 00:05:50.519 --> 00:05:52.759 and they will do what they like and nothing will 88 00:05:52.800 --> 00:05:55.680 stop them from hitting a straight line. But that's not true. 89 00:05:55.759 --> 00:05:58.560 Although they think, yeah, well it is. 90 00:05:58.720 --> 00:06:01.959 They behave as though they're following a straight line, but 91 00:06:02.079 --> 00:06:04.759 that straight line is distorted by the gravitational pull of 92 00:06:04.839 --> 00:06:07.160 something else, you know, like a cluster of galaxies. 93 00:06:07.800 --> 00:06:09.120 Yeah, so they are affected. 94 00:06:10.000 --> 00:06:13.360 They are affected, yes, but it's not quite the same 95 00:06:13.439 --> 00:06:16.279 as reflection or refraction as Colins proposed. 96 00:06:18.079 --> 00:06:19.240 Interesting, very interesting. 97 00:06:19.279 --> 00:06:21.360 It's a great question, Colin, and thank you for that. 98 00:06:21.639 --> 00:06:25.959 Yeah, absolute ripper. All right, thanks Colin. Our next question 99 00:06:26.639 --> 00:06:30.839 comes from Michael Whiting in Chroma in the UK. Hi, 100 00:06:31.000 --> 00:06:34.079 Andrew and Fred long term listener, and would like to 101 00:06:34.160 --> 00:06:37.879 say thank you for a brilliant podcast which I look 102 00:06:37.959 --> 00:06:42.560 forward to every week. Thank you. Thinking about the future, 103 00:06:42.759 --> 00:06:45.000 going back to the Moon, et cetera, is it possible 104 00:06:45.160 --> 00:06:48.319 to have a space station orbiting both Earth and the 105 00:06:48.439 --> 00:06:53.079 Moon in say technical terms a figure eight. I'm assuming 106 00:06:53.160 --> 00:06:56.040 it is possible, but radiation shielding is more the issue. 107 00:06:56.519 --> 00:06:59.839 This would surely make it easier to transit for Moon. 108 00:07:00.959 --> 00:07:04.040 That's his first question. When we deal with that one, 109 00:07:04.360 --> 00:07:08.040 I'll ask the second question. So I like this idea 110 00:07:08.160 --> 00:07:09.439 if it's feasible. 111 00:07:09.959 --> 00:07:14.120 Well, it is absolutely And that's actually if you've got 112 00:07:14.160 --> 00:07:17.480 to look back to nineteen sixty eight and look at 113 00:07:17.519 --> 00:07:20.920 the trajectory of Apollo eight exactly what it did. It 114 00:07:21.000 --> 00:07:24.079 followed a figure eight orbit around the Earth and the Moon, 115 00:07:25.680 --> 00:07:29.959 and that you could set up a stable for a 116 00:07:30.120 --> 00:07:35.560 bit like that, But it doesn't really make for an 117 00:07:35.560 --> 00:07:40.120 easier transit for Moon missions. Because if you've got something 118 00:07:40.160 --> 00:07:41.920 that's in a figure eight of a figure of eight 119 00:07:42.079 --> 00:07:44.759 orbit's going from Earth to going between the Earth and 120 00:07:44.839 --> 00:07:50.040 the Moon. When you you know, I suppose you imagine 121 00:07:50.079 --> 00:07:52.399 that's the kind of space station you want to jump 122 00:07:52.480 --> 00:07:56.240 on board it. To jump on board, you've got to 123 00:07:56.519 --> 00:08:00.399 have a spacecraft that is following exactly that orbit. Yeah, 124 00:08:00.560 --> 00:08:02.639 you've gotta loannch it and get it into that orbit 125 00:08:03.040 --> 00:08:07.519 in order for you to make the rendezvous between the two. Now, yes, 126 00:08:08.120 --> 00:08:11.839 maybe if you have a something like the Gateway that 127 00:08:12.120 --> 00:08:15.800 the Gateway satellite which is being proposed as part of 128 00:08:15.839 --> 00:08:22.240 the Artemis program, in orbit around the Moon, then that's 129 00:08:22.639 --> 00:08:25.040 like a space station which has lots and lots of 130 00:08:25.120 --> 00:08:28.920 facilities on board, which are a little transit shuttle might 131 00:08:28.959 --> 00:08:31.079 not have a transit shuttle, might look more like a 132 00:08:32.039 --> 00:08:37.159 crew dragon spacecraft or you know what are they called? 133 00:08:38.480 --> 00:08:42.440 I can never remember its name, the bullying what are you? 134 00:08:44.320 --> 00:08:46.440 Star liners? What that was the name I thought of, 135 00:08:46.600 --> 00:08:48.240 and I was thinking, No, it's not a star lineer 136 00:08:48.279 --> 00:08:49.000 that's an aircraft. 137 00:08:49.120 --> 00:08:49.600 No, but it is. 138 00:08:49.799 --> 00:08:52.519 It is. It's a star liner, yeah, the star liner. 139 00:08:53.080 --> 00:08:55.840 So you know, they're very modest pieces of equipment. They 140 00:08:55.879 --> 00:08:57.960 can hold up to seven people, but there will be 141 00:08:58.000 --> 00:09:02.480 a crowded, crowded house. So I guess you could do 142 00:09:02.600 --> 00:09:05.440 that if you've got this sort of gateway like space 143 00:09:05.519 --> 00:09:07.960 station that is constantly in a figure of eight orbit, 144 00:09:09.200 --> 00:09:13.120 and you zoom your passengers up to it, hop on 145 00:09:13.679 --> 00:09:16.120 and it acts like a boss, then you've got to 146 00:09:16.159 --> 00:09:18.080 hop off at the other end before it brings you 147 00:09:18.159 --> 00:09:21.360 back to Earth. I'm not sure that it would make 148 00:09:21.519 --> 00:09:23.840 life easier. I think it might make life a bit 149 00:09:23.919 --> 00:09:29.200 more complicated. But it could be done, Yes, it could 150 00:09:29.240 --> 00:09:29.519 be done. 151 00:09:30.000 --> 00:09:34.039 Yeah, all right, so you're thinking, is right, Michael, But 152 00:09:35.519 --> 00:09:40.679 operationally might prove too much of a headache. Michael's got 153 00:09:40.679 --> 00:09:46.000 another question. With China adding a new currently visible satellite constellation, 154 00:09:46.399 --> 00:09:51.360 our discussions being had to decrease the visibility of the 155 00:09:51.440 --> 00:09:57.840 satellites as was achieved with space x Starlink constellations. Follow 156 00:09:57.960 --> 00:10:03.679 up question to that, does China, Thanks Mike, and this. 157 00:10:03.960 --> 00:10:06.480 This question goes right to the heart of stuff. I 158 00:10:07.039 --> 00:10:11.840 talk about a lot, and you know part of my role. 159 00:10:12.879 --> 00:10:17.200 There's the astronomer on the loose. The answer is yes, 160 00:10:18.159 --> 00:10:21.000 kean Fan I think is the name of the satellite? 161 00:10:21.000 --> 00:10:23.440 Am I have that long? Because it's a few days 162 00:10:23.440 --> 00:10:26.080 since I looked at it. It means a thousand sales. 163 00:10:27.480 --> 00:10:31.960 That's the name of it. And there fifteen thousand satellites 164 00:10:32.120 --> 00:10:37.840 I think have been filed for in this constellation. All 165 00:10:37.879 --> 00:10:40.360 the evidence I think last time I looked there were 166 00:10:40.360 --> 00:10:44.840 about forty in orbit. Now with mounting evidence that they 167 00:10:44.879 --> 00:10:51.759 are pretty bright. Then as use exactly as as Michael says, 168 00:10:53.440 --> 00:10:57.279 SpaceX did a lot of work to reduce the visible 169 00:10:57.960 --> 00:11:04.200 light profile of the Stylink satellites. We don't think that's 170 00:11:04.279 --> 00:11:09.120 happened with Kian Fan, and we don't really have any 171 00:11:09.759 --> 00:11:14.919 avenues into the company that is running them in China. 172 00:11:16.519 --> 00:11:22.440 Now my hope is that this will change because we 173 00:11:22.600 --> 00:11:27.799 now have satellite constellation interference to dark and quiet skies. 174 00:11:27.879 --> 00:11:31.080 That is now an agender item on the Committee on 175 00:11:31.120 --> 00:11:33.360 the Peaceful Uses of Outer Space, the UN Committee on 176 00:11:33.399 --> 00:11:35.039 the Peaceful Use is of outer Space. They have a 177 00:11:35.120 --> 00:11:38.639 Science and Technical subcommittee and it's now an agender item 178 00:11:38.679 --> 00:11:44.720 on that committee, so that raises its profile. China is 179 00:11:44.799 --> 00:11:48.200 a player in this forum. They come to the party 180 00:11:48.360 --> 00:11:52.799 with the kopuas that committee. So my hope is that 181 00:11:52.919 --> 00:11:57.320 there will be avenues for improvement with that, But at 182 00:11:57.360 --> 00:11:59.279 the moment we don't know. 183 00:12:00.960 --> 00:12:04.120 Yeah, that's a pity. I mean, they have a vested 184 00:12:04.200 --> 00:12:10.759 interest in space exploration and understanding as much as anybody else, 185 00:12:10.879 --> 00:12:15.799 so I suspect that it would be in their best 186 00:12:15.879 --> 00:12:20.720 interest and they would benefit from insulating their satellites, so 187 00:12:20.879 --> 00:12:26.960 to speak, to reduce the impact on observational and radio 188 00:12:27.039 --> 00:12:28.480 astronomy from the ground. 189 00:12:28.519 --> 00:12:30.799 That's right. In fact, that's exactly the comment. I was 190 00:12:30.840 --> 00:12:33.080 in a meeting a few months ago now and I 191 00:12:33.200 --> 00:12:35.919 made exactly that comment that China has a very large 192 00:12:36.000 --> 00:12:41.919 cohort of astronomers who are themselves using well amongst the 193 00:12:41.960 --> 00:12:44.600 biggest single dish radio telescope in the world, the fast 194 00:12:44.639 --> 00:12:48.919 telescope five hundred meter radio dish, and they also have 195 00:12:49.039 --> 00:12:54.759 optical telescopes, so they would have a voice within China 196 00:12:55.000 --> 00:12:59.440 and hopefully the space industry in China will listen to them. 197 00:13:00.120 --> 00:13:03.360 So so my you know, I'm an eternal optimist Andrew, 198 00:13:03.360 --> 00:13:06.840 as you know. But the answer to Mike's last question 199 00:13:06.960 --> 00:13:11.159 does China listen? Is we hope they will. 200 00:13:11.960 --> 00:13:12.159 Yeah. 201 00:13:12.799 --> 00:13:18.000 Yeah, fair point and really great question to ask. Probably 202 00:13:19.720 --> 00:13:21.879 it's a scary question to ask because you just you 203 00:13:22.000 --> 00:13:24.080 don't know what China they get. They get offended at 204 00:13:24.159 --> 00:13:27.480 things out of the blue, and you know, and they 205 00:13:27.559 --> 00:13:30.480 stopped buying our wine and thanks it. 206 00:13:30.600 --> 00:13:35.519 Was twenty billion dollars worth of of trade exactly. Yeah. 207 00:13:35.960 --> 00:13:40.039 Anyway, great questions, Mike, Thanks for sending them in. This 208 00:13:40.360 --> 00:13:43.759 is Space Nuts Andrew Uncley with Professor Fred what's a 209 00:13:48.519 --> 00:13:52.000 Space Nuts. Yep, it's a Q and A edition where 210 00:13:52.120 --> 00:13:55.879 we answer audience questions. And we've got an audio question 211 00:13:56.120 --> 00:13:59.240 now from one of our regular sender in errors. It's 212 00:13:59.480 --> 00:14:00.799 Rusty for donny. 213 00:14:00.559 --> 00:14:04.639 Brook and Andrew, it's Rusty in donny Brook. When the 214 00:14:04.759 --> 00:14:10.519 Dark Energy said you really suck? What did the ultramassive 215 00:14:10.600 --> 00:14:16.360 black holes, say in response, nothing, it was to taken 216 00:14:16.399 --> 00:14:20.320 aback to get a word out. Now, if black hole 217 00:14:21.080 --> 00:14:25.919 truly generate dark energy, it's got to be a local 218 00:14:25.960 --> 00:14:31.799 phenomenon because our study of gravitational waves have shown us 219 00:14:31.840 --> 00:14:34.679 that space time distorts at speed of light. 220 00:14:36.879 --> 00:14:40.840 The effect would be too small to be able to 221 00:14:40.960 --> 00:14:46.279 measure it in stellar mass black holes, but as we 222 00:14:46.320 --> 00:14:51.600 get bigger the effect would be too clutted in super 223 00:14:51.639 --> 00:14:57.519 massive black holes in galaxies too, so that leaves ultra 224 00:14:57.639 --> 00:15:00.120 massive black holes in the center of large. 225 00:15:00.120 --> 00:15:05.919 Which, if there are any. The hair Wooden astronomer specializing 226 00:15:06.000 --> 00:15:13.399 in multiple objects spectrometry Fred make observations to gain support 227 00:15:13.440 --> 00:15:16.840 for the existence of such ultramatic black holes and the 228 00:15:16.919 --> 00:15:18.440 granular nature of dark energy. 229 00:15:19.679 --> 00:15:22.720 So this would replace the notion that large scale structure 230 00:15:22.720 --> 00:15:22.879 of the. 231 00:15:22.960 --> 00:15:27.960 Universe was caused by tonic oscillations in the early universe. 232 00:15:28.000 --> 00:15:28.159 Two. 233 00:15:28.879 --> 00:15:31.480 So thanks space nuts, have a good and. 234 00:15:33.360 --> 00:15:36.679 Thanks Rusty. I'm always worried about Rusty because he just 235 00:15:36.799 --> 00:15:39.600 tries to throw your curveball occasionally, Fred, And I don't 236 00:15:39.639 --> 00:15:41.120 know if he's just tried again. 237 00:15:41.960 --> 00:15:46.080 Yeah, I mean, the lovely thing about Rusty is that 238 00:15:46.200 --> 00:15:51.799 in three minutes. He rewrites all the textbooks. It throws away. 239 00:15:51.840 --> 00:15:54.240 The big bank throws away. Dark energes don't throw away. 240 00:15:54.240 --> 00:15:54.720 They do bag. 241 00:15:55.200 --> 00:15:57.639 But I see where he's the point he's making because 242 00:15:57.639 --> 00:16:02.080 we've covered this idea before that dark the ultimate source 243 00:16:02.120 --> 00:16:05.159 of dark energy might be black holes. That's some research 244 00:16:05.279 --> 00:16:11.200 that I think was done earlier this year, and so 245 00:16:12.279 --> 00:16:16.559 Rusty's conclusion from that is that dark energy must be clumpy, 246 00:16:18.879 --> 00:16:21.559 which I think is a reasonable conclusion. But I don't 247 00:16:21.799 --> 00:16:26.360 know that that is the conclusion that's drawn by the 248 00:16:26.399 --> 00:16:29.600 people who are the proponent of this theory. I need 249 00:16:29.720 --> 00:16:32.159 to go and have and I look back at the 250 00:16:32.240 --> 00:16:35.799 theory of black holes being the source of dark energy. 251 00:16:36.639 --> 00:16:38.720 But if there were, so, look, I'll rise to the 252 00:16:38.960 --> 00:16:46.360 challenge as a multi object spectroscopist, which I'm not really anymore, 253 00:16:46.480 --> 00:16:50.200 but I was, I wouldn't that this would not be 254 00:16:50.679 --> 00:16:53.679 the technique, the technique that you'd use though to detect them. 255 00:16:53.919 --> 00:16:59.519 So what what Rusty's proposing is that there are these 256 00:16:59.600 --> 00:17:03.240 things ultramassive black holes, which I guess we might say 257 00:17:03.279 --> 00:17:07.119 are more than one hundred billion times the massive the sun. 258 00:17:07.519 --> 00:17:12.519 They will there monsters, absolute monsters, and they're lurking around 259 00:17:13.440 --> 00:17:19.920 in the voids between galaxies. Now, those voids are part 260 00:17:20.039 --> 00:17:23.279 of the sort of honeycomb structure of the universe that 261 00:17:23.359 --> 00:17:25.839 we think was imprinted in the Big Bang. That the 262 00:17:26.920 --> 00:17:30.759 work that people do on the physics of the Big 263 00:17:30.839 --> 00:17:33.799 Bang event tell you that there will be these strings 264 00:17:33.799 --> 00:17:38.920 of dark matter which would collect hydrogen gas, which would 265 00:17:38.960 --> 00:17:42.359 form stars and galaxies and so. But those strings and 266 00:17:42.519 --> 00:17:45.599 sheets of dark matter make essentially what looks like a 267 00:17:45.720 --> 00:17:47.839 foam or a honeycomb pattern when you look on very 268 00:17:47.920 --> 00:17:50.200 large scales. So in the middle of that, there are 269 00:17:50.319 --> 00:17:51.279 very few galaxies. 270 00:17:51.640 --> 00:17:52.400 So if you put. 271 00:17:52.319 --> 00:17:55.720 An ultra massive black hole in the middle of that, 272 00:17:55.920 --> 00:17:59.440 what would you see? And the answer is you would 273 00:17:59.519 --> 00:18:03.440 expect to see when you looked in that direction, because 274 00:18:03.480 --> 00:18:05.359 you'll be able to see the galaxies on the far 275 00:18:05.559 --> 00:18:09.200 side of that void, a sheet of galaxies. You would 276 00:18:09.240 --> 00:18:12.680 expect their images to be distorted in the way that 277 00:18:12.839 --> 00:18:17.119 we are familiar with gravitational lensing by a massive massive object. 278 00:18:18.440 --> 00:18:24.759 And so I don't believe that such distortions have been found. 279 00:18:25.000 --> 00:18:27.079 In other words, you know what you might see is 280 00:18:27.559 --> 00:18:30.839 is nothing, because there's a black hole that sorry, you'd 281 00:18:30.880 --> 00:18:33.680 see no evidence of something in the in. 282 00:18:33.720 --> 00:18:34.559 The in the. 283 00:18:36.079 --> 00:18:38.920 Intermediate distance, but in the far distance you'll be able 284 00:18:38.960 --> 00:18:42.400 to see galaxies and clusters of galaxies whose light would 285 00:18:42.400 --> 00:18:45.119 be distorted by the black hole that you couldn't see 286 00:18:45.880 --> 00:18:48.200 in the foreground, if you see what I'm saying. So 287 00:18:48.359 --> 00:18:51.599 I think we have evidence already of such ultra massive 288 00:18:51.640 --> 00:18:52.240 black holes. 289 00:18:53.119 --> 00:18:56.400 Okay, So avoid with a black hole would give you 290 00:18:56.480 --> 00:19:00.839 a vision of distorted galaxies and it's behind it, whereas 291 00:19:01.039 --> 00:19:04.640 a void without a black hole, you just wouldn't see anything. 292 00:19:05.799 --> 00:19:08.039 You'd see the galaxies, but they wouldn't look any from 293 00:19:08.039 --> 00:19:10.799 what they normally look. Yeah right, you know you can 294 00:19:11.160 --> 00:19:14.680 we know from particularly from the new web images, just 295 00:19:14.839 --> 00:19:18.960 how distorted the shapes of galaxies are when when they're 296 00:19:19.000 --> 00:19:23.599 seen through a gravitational lens caused by a cluster of 297 00:19:23.720 --> 00:19:27.279 galaxies in the foreground. So yeah, it's an interesting question though, 298 00:19:27.359 --> 00:19:33.440 as Rusty is always always are Yeah, yeah, he's always thinking. 299 00:19:33.680 --> 00:19:35.640 That's the thing, and that's that's what it's all about, 300 00:19:36.480 --> 00:19:39.119 to provoke thought and come up with ideas and try 301 00:19:39.200 --> 00:19:42.759 to try to challenge those in the in the astronomical 302 00:19:42.839 --> 00:19:46.160 seats of power, such as your good self read yeah, 303 00:19:46.279 --> 00:19:55.400 always always throwing out the challenge, Thank you, Rusty pace Nuts. 304 00:19:55.799 --> 00:19:59.680 And our final question reflects on an issue we spoke 305 00:19:59.720 --> 00:20:02.880 about but fairly recently. This comes from Mark. 306 00:20:04.000 --> 00:20:04.119 Hi. 307 00:20:04.200 --> 00:20:07.559 It's Mark in London and Canada. I was wondering you 308 00:20:07.640 --> 00:20:11.720 were talking recently about the astronauts being stranded and the 309 00:20:12.480 --> 00:20:18.240 Boeing spacesuit being incompatible with the SpaceX vehicle. I was wondering, 310 00:20:18.319 --> 00:20:20.920 what does that mean? Why can't they just wear their suit? 311 00:20:21.240 --> 00:20:25.319 What does the soup plug into the vehicle or what's 312 00:20:25.400 --> 00:20:30.720 the incompatibility? Appreciate an explanation of that, Thanks, guys, and 313 00:20:31.799 --> 00:20:33.759 I figure hughes but in that studio for the best 314 00:20:33.799 --> 00:20:36.839 part of the decade. So it's time to free who 315 00:20:37.039 --> 00:20:38.559 when just started a campaign to let them go on? 316 00:20:38.960 --> 00:20:43.279 Thanks, start a petition, Mark, because I'm not going to 317 00:20:43.319 --> 00:20:49.039 help him. Gosh, people are starting to sympathize with Hugh 318 00:20:49.319 --> 00:20:54.920 and starting to worry me a lot. I'm sounding really 319 00:20:55.000 --> 00:20:56.759 evil now you are. 320 00:20:56.880 --> 00:21:01.640 Yeah, you know, look, God, I think I think he 321 00:21:01.839 --> 00:21:05.400 deserves a break. Really, he's got us to put up 322 00:21:05.440 --> 00:21:08.400 with for a start. Yeah, well that's true, that's very true. 323 00:21:09.920 --> 00:21:13.279 Mark asks about space suit compatibility. Now we go back 324 00:21:13.319 --> 00:21:18.079 to that situation where there were I think, with three 325 00:21:18.200 --> 00:21:21.640 astronauts on the International Space Station who couldn't get back 326 00:21:21.680 --> 00:21:23.799 on the Boeing star Liner because of a fault, so 327 00:21:23.960 --> 00:21:26.759 it was sent back empty and they were to be 328 00:21:26.880 --> 00:21:28.599 returned on a space X. 329 00:21:31.240 --> 00:21:31.519 Rocket. 330 00:21:32.200 --> 00:21:36.240 Yeah if you like. But their suits, the Boeing suits 331 00:21:36.960 --> 00:21:42.519 didn't work in the space X vehicle, and there was 332 00:21:42.599 --> 00:21:45.839 talk about sending them back in their underpants or something 333 00:21:47.119 --> 00:21:51.559 because they just, you know, their suits were useless an emergency. 334 00:21:51.640 --> 00:21:54.000 Yeah, that's right, it would two do astronauts, not three 335 00:21:54.039 --> 00:21:56.759 as well. It's sort of Tony Williams and Butch will Moore. 336 00:21:57.160 --> 00:22:02.400 That's right. Yeah, and they're coming back. Are they still there? 337 00:22:02.799 --> 00:22:06.119 Yeah, they don't have it. That still February, that's right. 338 00:22:06.240 --> 00:22:09.319 Yeah, that's right. Yeah, they're the bowing star Liners back. 339 00:22:09.720 --> 00:22:13.440 All good and well, but they're still up there. Mark's 340 00:22:13.480 --> 00:22:15.599 question is a good one. Why can't they just wear 341 00:22:15.680 --> 00:22:17.000 their suits? What's the problem. 342 00:22:18.119 --> 00:22:22.880 So what's happened is that when the SpaceX it's not 343 00:22:22.960 --> 00:22:26.480 a rescue vehicle because it was already scheduled, but when 344 00:22:26.519 --> 00:22:31.160 that SpaceX craft went up to rendezvous of the ISS, 345 00:22:31.279 --> 00:22:33.920 which was last month, was it or earlier this month? 346 00:22:33.920 --> 00:22:36.720 I can't remember. I think it's last month. It took 347 00:22:37.359 --> 00:22:39.880 SpaceX suits up with it. It had a crew of 348 00:22:39.960 --> 00:22:42.799 only two rather than four, and two empty suits for 349 00:22:43.519 --> 00:22:47.039 Butcher Williams, sorry Butcher Willmore and Sunny Williams to come 350 00:22:47.119 --> 00:22:53.519 back with, why do they need that? Well, the star 351 00:22:53.640 --> 00:22:58.880 Liner and the SpaceX Dragon Capsule are completely different. They 352 00:22:58.960 --> 00:23:05.480 were developed independently, and in many ways, NASA wanted two 353 00:23:05.640 --> 00:23:10.000 different ways of transporting their astronauts up and down to 354 00:23:10.039 --> 00:23:15.279 the space station because it gives them a choice, that's 355 00:23:15.359 --> 00:23:17.960 the thing. And it turns out that it's just as 356 00:23:18.000 --> 00:23:22.680 well that they did, because these you know, SpaceX has 357 00:23:22.759 --> 00:23:27.039 had far fewer problems than than Boeing have. If we've 358 00:23:27.079 --> 00:23:30.599 been waiting for Boeing, we would still be waiting, whereas 359 00:23:30.720 --> 00:23:33.240 Crew Dragon has been flying I think since twenty twenty 360 00:23:33.359 --> 00:23:36.079 or thereabouts, quite a while ago, maybe twenty twenty two. Anyway, 361 00:23:36.640 --> 00:23:41.960 they're different spacecraft. They've got different you know, umbilical fittings, 362 00:23:42.079 --> 00:23:48.240 they have different restraint fittings, an entirely different appearance. The 363 00:23:48.319 --> 00:23:51.119 way to check this out, mark is to have a 364 00:23:51.200 --> 00:23:56.400 look at the USA Today website, and there is a 365 00:23:56.480 --> 00:24:00.359 story on that which is entitled you Can't use line 366 00:24:00.400 --> 00:24:04.000 of spacesuits in a SpaceX capsule. These images show why, 367 00:24:04.720 --> 00:24:08.480 and it becomes very obvious because all the plumbing is different. 368 00:24:08.559 --> 00:24:12.680 The spacesuits are themselves quite different. They've got different helmets, 369 00:24:13.559 --> 00:24:18.599 different fittings, different boots, different gloves. Everything's different, and they're 370 00:24:18.640 --> 00:24:21.720 not compassible. That's the bottom line. But it's a very 371 00:24:21.799 --> 00:24:25.200 nice article. Actually, it's got some lovely diagrams and illustrations 372 00:24:25.920 --> 00:24:30.160 showing the differences there. USA Today dot com is the 373 00:24:30.240 --> 00:24:31.079 place to help for that. 374 00:24:31.839 --> 00:24:34.200 I I just found it and I'm just having a 375 00:24:34.279 --> 00:24:36.240 quick squeeze through it, and yeah, you're right, there's some 376 00:24:36.319 --> 00:24:40.480 great diagrams and information in there. And now, just to 377 00:24:41.000 --> 00:24:44.400 clarify it a bit more, I assume when you come 378 00:24:44.480 --> 00:24:48.799 back to Earth you can technically do it without a spacesuit. 379 00:24:49.599 --> 00:24:51.960 So it's not like you have to have the suit 380 00:24:52.039 --> 00:24:53.880 on so that you can breathe or anything like that. 381 00:24:54.759 --> 00:25:00.559 No, that's right. It's it's basically a precaution. You know, 382 00:25:00.720 --> 00:25:05.160 if the if on re entry the spacecraft sprang a leak, 383 00:25:05.200 --> 00:25:08.319 for example, and started depressurizing, if you didn't have your 384 00:25:08.359 --> 00:25:11.039 spacesuit on, you'll be in big trouble. But that's an 385 00:25:11.119 --> 00:25:16.079 unlikely event. They I don't think it's ever happened before, 386 00:25:16.240 --> 00:25:18.160 so it's. 387 00:25:19.519 --> 00:25:21.119 It's it's. 388 00:25:22.799 --> 00:25:25.480 They could have done it exactly as you've said, had 389 00:25:25.519 --> 00:25:30.519 there been an emergency, those astronauts Sonny Williams and Butch 390 00:25:30.559 --> 00:25:33.640 Wilmore could have come back in a crew Dragon flight. 391 00:25:33.839 --> 00:25:38.839 I think they were rigging up sort of emergency seats 392 00:25:38.880 --> 00:25:41.160 in one of the crew Dragon craft just in case 393 00:25:41.319 --> 00:25:43.759 this needed to happen. But yeah, they wouldn't have had 394 00:25:44.039 --> 00:25:49.720 had a spacesuit, so's it would not have been possible 395 00:25:49.759 --> 00:25:51.640 for them to wear spaces on their way back. But 396 00:25:51.759 --> 00:25:55.240 that will not now be the case. That's fixed because 397 00:25:55.319 --> 00:25:59.920 there are now two extra SpaceX spacesuits on the Internet 398 00:26:00.200 --> 00:26:03.279 Space Station for them to come back when they returning February. 399 00:26:03.880 --> 00:26:06.480 And I do like you know that that article that 400 00:26:06.559 --> 00:26:08.880 I just mentioned, the one you've just found, it's got 401 00:26:08.920 --> 00:26:12.880