WEBVTT 1 00:00:00.200 --> 00:00:03.200 Hello, thanks for joining us. This is Space Nuts. I'm Andrew Dunkle, 2 00:00:03.359 --> 00:00:06.040 your host, and it's so good to have your company once again. 3 00:00:06.719 --> 00:00:11.400 And coming up on this episode, it is all questions because it's episode three 4 00:00:11.480 --> 00:00:15.400 hundred and fifty, and that's when we dedicate our show to the audience to 5 00:00:15.720 --> 00:00:20.839 nail down such questions as those of stellar mass, black holes, our place 6 00:00:20.920 --> 00:00:24.079 in the universe, and where that place might be in the future because it's 7 00:00:24.120 --> 00:00:28.640 moving. Is there a size limit to rocky planets. We're going to look 8 00:00:28.640 --> 00:00:33.240 at expansion limits, expansion effects, asteroids, space time, and photons. 9 00:00:33.320 --> 00:00:40.399 All questions coming from our vast audience of nine here on Space Nuts. Hope 10 00:00:40.399 --> 00:00:46.119 you can hang around a while. Dan Sack and Rad in Ternel ten nine 11 00:00:46.679 --> 00:00:56.960 Magnian sequenced Space Nuts three two two one Space Nuts and actually report a bill 12 00:00:57.079 --> 00:01:02.280 good and joining me to discuss all of that and much much more is Professor 13 00:01:02.399 --> 00:01:04.840 Fred Watson, a storm Er at Large. Hello Fred, Hello Andrew, 14 00:01:06.640 --> 00:01:10.319 very good to be at large again. If I haven't caught you yet, 15 00:01:12.040 --> 00:01:18.760 not at all. We've got a smashing program. It's there's so much to 16 00:01:18.840 --> 00:01:23.280 talk about today, so I think we'll just hose straight in and get stuck 17 00:01:23.319 --> 00:01:30.120 into it. And our very first question comes from none other than Hallo Space 18 00:01:30.319 --> 00:01:38.400 Nuts, Margin Burman Gorvyn here, writer extraordinaire in many genres, and today 19 00:01:38.599 --> 00:01:49.400 we're crossing my strength in science fiction with horror as we ask how close could 20 00:01:49.719 --> 00:01:57.920 a spacecraft with human beings aboard realistically get to a stour mass black hole before 21 00:01:59.280 --> 00:02:07.439 all the inside our fried and or linguinified, which I think sounds better than 22 00:02:07.519 --> 00:02:14.800 spaghettified, don't You can't wait to hear the answer? Margin Burming Gorvine in 23 00:02:14.960 --> 00:02:20.919 Potomac, Maryland here over and act linguinified. Yeah, yeah, with that 24 00:02:21.840 --> 00:02:24.759 or with that? Yeah that's not bad? Um? Yeah, how close 25 00:02:24.919 --> 00:02:31.000 is too close? So I suppose the answer is it depends? Uh, 26 00:02:31.319 --> 00:02:39.199 it does, doesn't it? Yeah? I am um so somewhere and here 27 00:02:39.240 --> 00:02:45.560 we go. This is the the usual um tribute to one of my books, 28 00:02:46.120 --> 00:02:53.520 but I can't remember which one, which Chat's five episodes? Sorry, 29 00:02:53.520 --> 00:02:57.879 I'm not naming any at least I don't think I'm going to um. I 30 00:02:58.039 --> 00:03:04.800 did write about the event. Horizon divers are a stellamass black hole, and 31 00:03:04.879 --> 00:03:10.439 I can't remember what it is, but it's it's relatively compact, measured in 32 00:03:10.800 --> 00:03:16.639 kilometers if I remember rightly, But the event horizons not really what would sort 33 00:03:16.719 --> 00:03:22.840 you out in you know, in the answer to Martin's question, because yes, 34 00:03:22.960 --> 00:03:30.840 you'd be linguinified spaghettified. You probably would even be result of fired as 35 00:03:30.879 --> 00:03:36.439 well, because you might end up in bids when you got within a much 36 00:03:36.560 --> 00:03:45.520 closer distance. Um, So here is a something I'm pulling out of my 37 00:03:45.680 --> 00:03:51.400 memory from only about four weeks ago. There is a there's a gas cloud 38 00:03:51.719 --> 00:04:00.639 which is currently orbiting the it's not orbiting, it's passing by the supermassive black 39 00:04:00.680 --> 00:04:04.360 hole in the center of our galaxy. Now that's not a tellomass black hole, 40 00:04:04.400 --> 00:04:09.360 which is what Martin's asking about. This is a three point six million 41 00:04:09.439 --> 00:04:14.719 stellar mass black hole. This, this gas cloud is passing within a few 42 00:04:15.000 --> 00:04:17.800 trillion kilometers if I remember rightly, of the black hole, and it is 43 00:04:17.879 --> 00:04:24.439 being spaghettified. It's been watched, it's been observed to do that over quite 44 00:04:24.439 --> 00:04:30.160 a long period. Notwithstanding that a few more million trillion kilometers there are stars 45 00:04:30.199 --> 00:04:33.319 happily in orbit around the supermassive black hole. So I don't haven't done the 46 00:04:33.360 --> 00:04:42.279 calculation, Martin. It's probably conjecture as to you know what, at what 47 00:04:42.879 --> 00:04:50.480 level do the tidal forces separating your head and your feet start to become significant 48 00:04:50.680 --> 00:04:56.839 enough that they overcome the the you know, the stomic forces which are holding 49 00:04:56.920 --> 00:05:02.560 your atomies together. And that's a calculation that I haven't done. But it's 50 00:05:03.439 --> 00:05:06.480 even for a stellar mass black hole, it's probably not very far away. 51 00:05:06.560 --> 00:05:11.560 I think the title forces that you would experience would would really start to make 52 00:05:11.600 --> 00:05:16.759 things uncomfortable, Okay, And which one is the stella mass black hole? 53 00:05:16.800 --> 00:05:26.160 Again, in terms of the size of black holes, it's the massive one 54 00:05:26.319 --> 00:05:30.839 star. Stella mass is one star, right, Okay, gotcha, hen's 55 00:05:30.839 --> 00:05:34.959 the name. Yes, sorry, sorry, I'm I'm being lived there, 56 00:05:35.040 --> 00:05:39.959 But that's right. It's an object of the order of the massive one star, 57 00:05:40.360 --> 00:05:44.560 which sometimes includes things up to twenty or thirty times the mass of the 58 00:05:44.639 --> 00:05:47.519 song. But it's still not a super massive black hole. And it's not 59 00:05:47.600 --> 00:05:50.399 the other thing that we've talked about from Touch to Town. The intermediate mass 60 00:05:50.480 --> 00:05:57.279 black calls things of order a thousand times the mass of the song, which 61 00:05:57.560 --> 00:06:01.279 which quite rare, we believe, and very much unlike the ultra massive black 62 00:06:01.319 --> 00:06:08.839 hole that we talked about four weeks ago, that's bigger than big. Just 63 00:06:09.000 --> 00:06:11.720 wait for the hypermassive black hole. That's the next one to come up. 64 00:06:11.759 --> 00:06:13.839 Well, it could happen, couldn't it? And did it? Could? 65 00:06:13.959 --> 00:06:17.959 You just never know these things, these like we when we started the podcast 66 00:06:18.040 --> 00:06:25.839 and write through several episodes or several years of episodes, we could only confirm 67 00:06:25.920 --> 00:06:30.680 there were two yes, moall and large. Now we've got yeah, yeah, 68 00:06:30.959 --> 00:06:35.279 loads different, including that ultra massive black hole that we talked about. 69 00:06:35.360 --> 00:06:41.800 That's sort of pushing the limits of which we thought black holes could exist. 70 00:06:41.920 --> 00:06:46.839 We thought that couldn't exist. I can't remember what it was. Was it 71 00:06:46.560 --> 00:06:51.920 thirty billion or thereabout? It was some astronomical numbs a huge number. Yeah, 72 00:06:53.040 --> 00:06:56.519 yeah, yeah, it was amazing. Um. So the answer to 73 00:06:56.600 --> 00:07:00.639 Martin's question is, in real terms, you could get reasonably close, but 74 00:07:02.120 --> 00:07:06.120 not but not that close. Sorry Martin, we haven't given you another for 75 00:07:06.160 --> 00:07:13.759 at all. We've just talked about. But reasonably close is what I think. 76 00:07:15.000 --> 00:07:15.800 Yeah, I don't think you'd want to get you know, if it 77 00:07:15.879 --> 00:07:19.480 was at the center of the solar system. I don't think you want to 78 00:07:19.519 --> 00:07:24.319 get much nearer than such an r neptune. Sorry, your readers, so 79 00:07:25.519 --> 00:07:30.160 well, no one wants to get hear that now. Okay, so Martin, 80 00:07:30.319 --> 00:07:34.800 that's a very loose answer to your question, but it's a good question 81 00:07:34.879 --> 00:07:38.480 because you know, one day we might be able to get out there and 82 00:07:38.639 --> 00:07:41.199 get close to one of these things, and you just really, you really 83 00:07:41.240 --> 00:07:45.160 didn't need to do your mathematics before you lined yourself up. Bring it. 84 00:07:45.240 --> 00:07:49.600 Who came out of your space warp ups? I mentioned the name and got 85 00:07:49.680 --> 00:07:55.319 too close. Yeah, all right, thanks Martin. Great to hear from 86 00:07:55.360 --> 00:07:59.199 you. Let's go to a text question. This actually came in via email 87 00:07:59.560 --> 00:08:05.120 from Andrew. He says, I love the show. I have a science 88 00:08:05.319 --> 00:08:11.000 question. Does our Sun move its position as the planet's orbit? If so, 89 00:08:11.199 --> 00:08:15.240 by how much? Thanks? Andrew? Hit reply to respond. Now 90 00:08:15.279 --> 00:08:18.639 we'll just talk about that. Yeah, it's a great question, and the 91 00:08:18.720 --> 00:08:26.199 answer is yes, it does. And so basically the bottom line here is 92 00:08:26.319 --> 00:08:31.279 that the Sun in a sense, is not the center of the Solar system. 93 00:08:31.679 --> 00:08:35.240 The point at the center of the Solar system is something called the Barry 94 00:08:35.320 --> 00:08:39.960 center, which is the sort of it's like the center of gravity of the 95 00:08:41.000 --> 00:08:45.399 Solar System. So it includes not just the Sun but also the planets, 96 00:08:45.639 --> 00:08:50.639 of which really only one counts in this argument, and that's the planet Jupiter, 97 00:08:50.879 --> 00:08:56.519 which is, you know, the most massive of the Solar System's planets. 98 00:08:58.879 --> 00:09:01.240 So, but the Barry center, that's to say, this center of 99 00:09:01.320 --> 00:09:09.240 gravity does actually move around with respect to the Sun, or should I say 100 00:09:09.279 --> 00:09:15.200 the Sun moves around with respect to the Barrier center. And it's that process 101 00:09:15.360 --> 00:09:18.960 that actually allows us to detect the planets of other stars. Because if you've 102 00:09:20.000 --> 00:09:24.639 got if you've got a object in deep space, a star, you know, 103 00:09:24.720 --> 00:09:28.360 one hundred light years away, all you can observe is its light and 104 00:09:28.440 --> 00:09:33.320 its spectrum. But what you can see is it's velocity changing slightly as the 105 00:09:33.399 --> 00:09:37.320 planets pullets, you know, slightly one way or the other. And you 106 00:09:37.399 --> 00:09:43.879 can actually disentangle how many planets there are around at the star without being able 107 00:09:43.919 --> 00:09:48.039 to see any of them, just by knowing how the star moves with respect 108 00:09:48.120 --> 00:09:52.039 to the barri center. It's that movement that you can see reflected in the 109 00:09:52.080 --> 00:09:56.519 star's velocity. And in fact, we can now detect motions of stars with 110 00:09:56.679 --> 00:10:03.639 an accuracy measured believe it or not, in centimeters per second. Rather than 111 00:10:03.000 --> 00:10:07.879 well the work I did, you were doing well if you got down to 112 00:10:07.960 --> 00:10:13.840 a kilometer per second accuracy, but meter per second accuracy has been attainable for 113 00:10:13.919 --> 00:10:18.399 a long time, but now people are talking about sentimeter per second accuracy in 114 00:10:18.519 --> 00:10:22.960 the speed of a star that you can detect if I remember rightly, the 115 00:10:22.120 --> 00:10:30.080 planet Jupiter changes the Sun's velocity by around eleven meters per seconds, right to 116 00:10:30.240 --> 00:10:35.000 detect. Yeah, if to detect a Jupiter sized planet in the same orbit 117 00:10:35.039 --> 00:10:39.080 as Jupiteres, but around another star rather than the Sun, you would see 118 00:10:39.399 --> 00:10:43.600 motions of that star of eleven meters per second as it moves with respect to 119 00:10:43.639 --> 00:10:50.679 the Barrit Center. Now, Andrew's other part of his question was how much 120 00:10:50.759 --> 00:10:52.960 does it move? How much does the Sun move with respect to the center 121 00:10:54.000 --> 00:10:58.559 of gravity of the Solar system, And it's basically not much, but that 122 00:10:58.759 --> 00:11:05.799 Barry center does actually from time to time it is outside the Sun rather than 123 00:11:05.879 --> 00:11:11.440 being within it. So you're talking about the Sun moving by, you know, 124 00:11:11.919 --> 00:11:15.480 some fraction of its diameter. It might be quite a large fraction. 125 00:11:16.360 --> 00:11:20.559 It's not millions of kilometers. It's well, actually the Sun is one point 126 00:11:20.600 --> 00:11:24.600 formula kilometers in diameter, so it might be millions of kilometers, but but 127 00:11:26.440 --> 00:11:31.399 you know, more likely to be tens of hundreds of thousands. That's which 128 00:11:31.480 --> 00:11:33.879 means that the Barris center is for the most part inside the Sun, but 129 00:11:35.000 --> 00:11:39.000 it does occasionally go outside when you reckon. When you include the effect of 130 00:11:39.080 --> 00:11:41.039 all the planets that include Saturn as well, it's one of the Jupiter. 131 00:11:41.799 --> 00:11:46.519 I suppose the other way to describe the movement would be that that wobble we 132 00:11:46.639 --> 00:11:52.759 talk about when they're trying to detect planets around other stars, that that's one 133 00:11:52.759 --> 00:11:56.240 of the mythos, isn't it. Yeah, exactly what that wobble is the 134 00:11:56.320 --> 00:12:01.759 eleven kilometers per second in the place of Jupiter el the song Dopler wobbles technique. 135 00:12:01.799 --> 00:12:07.039 It's called yeah, yeah, very good. Thanks Andrew, hope you're 136 00:12:07.080 --> 00:12:09.080 doing well. Let's go on to our next question. This comes from Tom 137 00:12:09.200 --> 00:12:13.000 in Ireland. He said, Hi, my brain hurts, please help. 138 00:12:13.039 --> 00:12:18.960 Paracetamol or iberprofen is very good. For that time, thirteen point eight billion 139 00:12:18.039 --> 00:12:22.960 years ago, the universe began and has been expanding ever since. How is 140 00:12:22.000 --> 00:12:26.360 it that we can see objects up to twelve billion light years away in one 141 00:12:26.399 --> 00:12:31.320 direction and also in the opposite direction. If we are seeing these objects where 142 00:12:31.360 --> 00:12:37.200 they were twelve billion years ago, which means they were twenty four billion years 143 00:12:37.320 --> 00:12:41.120 apart. How could they have originated at the same point thirteen point eight billion 144 00:12:41.240 --> 00:12:46.000 years ago? Please help love the show Tom in Ireland. I think he's 145 00:12:46.039 --> 00:12:52.480 getting his light years and his universal age years mixed up. Possibly, No, 146 00:12:52.600 --> 00:13:01.120 it's it is. It's a confusing thing because yeah, and your age 147 00:13:01.200 --> 00:13:03.279 years is a good point, because we talk in terms of lookback times. 148 00:13:03.399 --> 00:13:11.720 That's the kind of usual phrase, and so it's misleading to say Gallex is 149 00:13:11.759 --> 00:13:18.320 twelve billion light years away and unless you qualify it by adding in the in 150 00:13:18.440 --> 00:13:24.759 the co moving coordinate system, and not many people do, I know, 151 00:13:24.919 --> 00:13:31.240 I don't know. There you go, So the bottom it's better to talk 152 00:13:31.279 --> 00:13:35.919 in terms of look back times, because that's the sort of fundamental thing. 153 00:13:35.000 --> 00:13:43.559 When you see an object in very the very distant universe, it's seeing it 154 00:13:43.679 --> 00:13:46.200 as it was, maybe when the universe was one point eight billion years old. 155 00:13:46.240 --> 00:13:50.399 If it's if it's got a twelve billion year lookback time, but it's 156 00:13:50.440 --> 00:13:56.000 actual distance is much more than twelve billion light years, because the universe has 157 00:13:56.080 --> 00:14:03.399 expanded by a huge amount since their light left that object. So the the 158 00:14:03.919 --> 00:14:07.240 what you might call in fact, it's got a name, it's called the 159 00:14:07.320 --> 00:14:16.600 proper distance would be something like thirty maybe thirty five billion light years away because 160 00:14:16.639 --> 00:14:20.919 of the expansion of the universe. But that's something that you can't actually measure 161 00:14:20.960 --> 00:14:26.320 in any way, that distance, because all we see is the light that's 162 00:14:26.399 --> 00:14:31.399 reached us after it's twelve billion year journey. And so it's more accurate to 163 00:14:31.480 --> 00:14:37.279 talk about look back time of four billion years than to say a distance of 164 00:14:37.679 --> 00:14:41.399 a look back time of twelve billion years, rather than a distance of twelve 165 00:14:41.440 --> 00:14:46.039 billion light years, unless you say it's a co moving distance, which is 166 00:14:46.120 --> 00:14:54.080 the distance which doesn't account for the expansion of the universe. Good grief kind 167 00:14:54.120 --> 00:14:58.360 of equates to the question we often get about where is the center of the 168 00:14:58.480 --> 00:15:01.159 universe and where we are? Where are we in it? Well, we 169 00:15:01.240 --> 00:15:05.120 are in it, that's rightly speaking. Yeah, so sorry, and Tom, 170 00:15:05.159 --> 00:15:09.679 I didn't really answer probably the address your question about things being separated by 171 00:15:09.720 --> 00:15:16.360 twenty eight and sorry, twenty four billion light years. And that's all that 172 00:15:16.679 --> 00:15:20.639 is saying, Yes, we see things receding from us in different directions. 173 00:15:20.759 --> 00:15:24.840 And the Hubble law seems to work everywhere whatever direction you're looking, and the 174 00:15:24.879 --> 00:15:31.399 Hubble law is the one that relates. It's this velocity of the velocity away 175 00:15:31.440 --> 00:15:35.559 from us of an object to its distance. It's how we know that redshift 176 00:15:35.600 --> 00:15:41.240 equals distance in the you know, standard cosmological model of the universe. So 177 00:15:43.519 --> 00:15:48.000 what what that is telling you is that the universe, first of all, 178 00:15:48.120 --> 00:15:56.000 is extremely big. And we think that when it kicked off within the first 179 00:15:56.120 --> 00:15:58.759 gazillions to the second, in fact, about tenth of minus thirty three of 180 00:15:58.799 --> 00:16:03.720 us and if I remember the number rightly, it expanded very violently in this 181 00:16:03.000 --> 00:16:10.240 period we call the Age of inflation, which only lasted a few quintillions of 182 00:16:10.320 --> 00:16:14.240 a second, but blew up the universe from the size of a p to 183 00:16:14.360 --> 00:16:18.519 the size of a galaxy. And then the expansion sort of settled down. 184 00:16:18.559 --> 00:16:22.919 But that's how we think. That's why we think the universe looks the same 185 00:16:23.039 --> 00:16:29.200 in all directions, even though it's very very large and the distances separating objects 186 00:16:29.320 --> 00:16:33.559 is very very extreme. We think at one time everything was very close together, 187 00:16:33.879 --> 00:16:37.440 and then it wasn't. And that's why we she what was she today? 188 00:16:38.519 --> 00:16:41.720 Okay, Tom's headache is throbbing now, Yes, probably, Yeah. 189 00:16:42.120 --> 00:16:45.399 I go for asprints, actually you know you do? Yeah, yeah, 190 00:16:47.559 --> 00:16:52.000 I just go around trying to find willow trees and lick the bark. Okay, 191 00:16:52.320 --> 00:16:56.840 all right, I wondered what you were doing. That's that's a natural 192 00:16:56.919 --> 00:17:00.960 pankiller. I didn't know that. Hell, that's that's I think that's how 193 00:17:02.000 --> 00:17:07.519 aspurin was invented. Not sure something like that. Yeah, willow is a 194 00:17:07.599 --> 00:17:11.240 natural has a natural painkilling property in it. It does. Thank you, 195 00:17:11.319 --> 00:17:15.880 Tom. Great to hear from you. This is space Nuts with Andrew Duntley 196 00:17:15.960 --> 00:17:22.519 and Professor Fred. What's a space nuts? Now? Fred to a regular 197 00:17:22.599 --> 00:17:29.559 contributor to our question answer session, and it's Duncan from Weymouth. I think 198 00:17:29.680 --> 00:17:33.759 I'm pretty sure he'll tell me that's where he's from. Hello, Duncan. 199 00:17:33.920 --> 00:17:41.319 Hear from Weymouth in the UK. Another quick question. I know that Andrew 200 00:17:41.440 --> 00:17:47.279 likes hypothetical one, so here's one that's been bugging me for a while. 201 00:17:48.519 --> 00:17:53.799 If you could get a huge mass of rock together, say, well, 202 00:17:53.839 --> 00:18:00.759 I don't know, a hundred times Jupiter's mass of solid rock in one place 203 00:18:02.039 --> 00:18:06.440 and put it in either they wore a bit around a star. Would it 204 00:18:06.559 --> 00:18:14.559 form a really massive rocky planet? Or is there an upper limits to how 205 00:18:14.799 --> 00:18:21.480 big or how massive a rocky planet can be? Just interested to know and 206 00:18:22.279 --> 00:18:27.359 if it couldn't form a massive, massive rocky planet, what would actually happen 207 00:18:27.440 --> 00:18:33.839 to that rock to prevent it becoming a rocky planet. Would it somehow not 208 00:18:33.960 --> 00:18:40.079 be able to be bound together, or would it melt or boil and form 209 00:18:40.160 --> 00:18:45.440 a gas or what would prevent that? Okay, keep up the good work 210 00:18:45.920 --> 00:18:51.000 and thanks for your efforts. Bye bye, thank you. Duncan m I 211 00:18:51.279 --> 00:18:53.319 kind of become a type of belt or an asteroid belt or something like that 212 00:18:53.359 --> 00:18:56.880 if it couldn't form a planet would have to sort of break up like that? 213 00:18:57.039 --> 00:19:03.000 But how big is the limit? That's they So, yeah, it's 214 00:19:03.000 --> 00:19:11.119 a really interesting question. And I think the limit is imposed is imposed not 215 00:19:11.279 --> 00:19:18.240 by the physics of how big something can be. It's more about how things 216 00:19:18.359 --> 00:19:27.440 evolve when planetary systems are formed. So we think that rocky planets do evolved 217 00:19:27.480 --> 00:19:34.240 by the sort of silicon material in the original dust and gas cloud that formed 218 00:19:34.279 --> 00:19:40.920 the Solar System. We think that stuff all stuck together became solidified turned into 219 00:19:41.160 --> 00:19:45.200 rock. These bits are rock bashed into one another, some stuck together, 220 00:19:45.319 --> 00:19:49.039 some didn't. But in the end you got planets building into a sort of 221 00:19:49.799 --> 00:19:56.480 rocks building into planetismals and then to protoplanets and eventually two planets. But this 222 00:19:56.680 --> 00:20:03.680 is all taking place within an environment that is very very gasy. And if 223 00:20:03.759 --> 00:20:14.480 you form rocky cause that start getting very big, you will also a mass 224 00:20:15.200 --> 00:20:18.240 gas you want just you don't want just to create rock, you'll acret gas 225 00:20:18.359 --> 00:20:23.680 as well. And that's why we think the gas giants are gas giants, 226 00:20:23.759 --> 00:20:30.119 because they grew big enough that they not only collected more bits of rock, 227 00:20:30.400 --> 00:20:36.200 they actually collected very significant envelopes of gas around them. And it sort of 228 00:20:36.319 --> 00:20:41.160 helped as well by them what we call the frost line or the ice line 229 00:20:41.960 --> 00:20:48.079 in the Solar system, that region which is between the orbits of Miles and 230 00:20:48.160 --> 00:20:53.920 Jupiter, where where ice actually forms because the temperatures low enough. Yeah, 231 00:20:55.039 --> 00:20:59.119 and so that the you know, the limits are more about the way you 232 00:20:59.240 --> 00:21:06.240 form planets rather than what could exist. Um, whether a hundred jupiter mass 233 00:21:06.359 --> 00:21:11.480 I mean a hundred jupiter mass solid, a hundred jupiter mass object is is 234 00:21:11.599 --> 00:21:18.759 actually a star because I think the the mass linits for brown dwarfs, is 235 00:21:18.000 --> 00:21:23.720 is it thirteen jupiter mass is up to about eighty I think in something in 236 00:21:23.799 --> 00:21:30.720 that range will produce deuterium burning and become what's called a brown dwarf star. 237 00:21:30.839 --> 00:21:33.759 But if you get above that, then you've got a dwarf star. Um 238 00:21:34.480 --> 00:21:40.440 So, but that's assuming it is made of gas. I think that the 239 00:21:40.559 --> 00:21:45.240 physics present prevent you from forming a rocky planet with anything like that kind of 240 00:21:45.319 --> 00:21:48.960 mass, because it would have created gas rather than create just more rock. 241 00:21:49.559 --> 00:21:56.680 Okay, that's that's pretty good though. I think we are discovering rocky planets 242 00:21:56.720 --> 00:22:00.920 that are much much bigger than Earth. Yeah, that's sort of up to 243 00:22:02.000 --> 00:22:08.480 neptune mass. But they're called super earths, so that yes, So what 244 00:22:08.839 --> 00:22:14.839 that's saying is that we we perhaps haven't achieved that limit within the Solar System. 245 00:22:15.119 --> 00:22:19.559 Yeah. Well, in the scheme of things, our rocky little world 246 00:22:19.720 --> 00:22:23.799 is actually one of the smaller ones, isn't it in real terms? Yeah, 247 00:22:23.960 --> 00:22:27.920 although it's hard to you know, the bottom line is that we're not 248 00:22:29.160 --> 00:22:37.000 really yet able to detect all the smaller planets that around stars because it's harder 249 00:22:37.039 --> 00:22:40.519 to detect them. You can do and there are programs that that you do 250 00:22:40.680 --> 00:22:44.799 that. Gravitational lensings. Want transit method lets you do it as well. 251 00:22:45.599 --> 00:22:52.279 But the and perhaps you know, the Kepler and tests spacecraft have both contributed 252 00:22:52.400 --> 00:22:56.880 many objects which are small compared with you know what we used to be finding, 253 00:22:57.000 --> 00:23:00.519 which were always the Jupiter of us. Things are bigger, so we 254 00:23:00.599 --> 00:23:04.279 are finding rocky planets. But there's still I think, gaps in our knowledge 255 00:23:04.640 --> 00:23:11.359 because when I've got the technology yet to define the smallest ones, so when 256 00:23:11.480 --> 00:23:15.119 we get that perfected, we might find a whole bunch thinks that a smaller 257 00:23:15.160 --> 00:23:18.960 than the Earth as well. Yeah, okay, thanks Duncan. Always good 258 00:23:18.960 --> 00:23:25.599 to hear from you. Jim is next. He's from something I can't pronounce, 259 00:23:26.319 --> 00:23:30.960 New Orleans. Yeah, New Orleans, it's Jim dear, Professor Watson, 260 00:23:30.039 --> 00:23:33.599 and mister Dunkley. I've been traveling by car a lot in the past 261 00:23:33.720 --> 00:23:38.359 year and was able to catch up on all your podcasts thus far, Blimy, 262 00:23:40.359 --> 00:23:44.160 I truly enjoy the show and look forward to the next episode. Onto 263 00:23:44.240 --> 00:23:48.160 my question. Because the bodies in the universe are accelerating at an ever increasing 264 00:23:48.319 --> 00:23:52.799 rate, eventually there will come a time when space time will become impracticable or 265 00:23:52.960 --> 00:23:56.880 space travel will become impracticable, if not impossible. What I mean is that, 266 00:23:56.960 --> 00:24:00.240 eventually, as a result of increasing excel leration, the velocity at which 267 00:24:00.279 --> 00:24:06.200 galaxies and their component parts move through the universe will attain a substantial percentage of 268 00:24:06.279 --> 00:24:11.119 the speed of light. If we cannot build spacecraft that attain speeds greater than 269 00:24:11.240 --> 00:24:15.400 that substantial percentage of the speed of light, then it seems that when a 270 00:24:15.480 --> 00:24:19.400 spaceship leaves the Earth's gravity, well, the Earth will become unreachable by the 271 00:24:19.799 --> 00:24:25.240 spaceship because the spaceship cannot catch up. Can this be right? There must 272 00:24:25.279 --> 00:24:26.880 be something that I'm missing. Thanks for your thoughts. Have a great day, 273 00:24:26.960 --> 00:24:33.319 Jim. Yeah, that's I can see where he's coming from. It 274 00:24:33.519 --> 00:24:37.119 is a quandary, And yes, we have talked about the fact that as 275 00:24:37.200 --> 00:24:41.599 things expand, we're eventually just going to be totally isolated in the universe. 276 00:24:41.680 --> 00:24:45.319 We won't be able to see anything else, which is due to happen in 277 00:24:45.319 --> 00:24:52.440 a couple of days. But what yeah, yeah, indeed, what's the 278 00:24:52.599 --> 00:24:59.400 what's the answer to Jim's quandity? I think on the body actually, because 279 00:25:00.240 --> 00:25:07.319 yes, if we look into the distant future, when the expansion has accelerated 280 00:25:07.440 --> 00:25:11.680 so that you know, you're talking about a hugely greater expansion of space time 281 00:25:12.200 --> 00:25:18.799 than we have at the moment, things will disappear beyond the horizon because the 282 00:25:19.480 --> 00:25:23.759 light that's leaving them now will never catch up with the expansion of the universe, 283 00:25:23.799 --> 00:25:26.359 so we won't see them. And that's the point that you were just 284 00:25:26.480 --> 00:25:32.640 making, Andrew, that we will have a very lonely existence when you look 285 00:25:32.680 --> 00:25:40.559 a few trillion years perhaps down the track, because there won't be anything other 286 00:25:40.640 --> 00:25:45.000 than the local group of galaxies visible. Maybe the local group will disappear as 287 00:25:45.039 --> 00:25:56.279 well. And I suppose what Jim's question about the spacecraft really means is that 288 00:25:56.599 --> 00:26:02.680 if the spacecraft could get far enough from the Earth so that it was being 289 00:26:02.839 --> 00:26:07.119 carried away from the Earth due to the expansion of the universe by a velocity 290 00:26:07.799 --> 00:26:11.880 higher than the velocity of the spaceship could have achieved, then yes, you're 291 00:26:11.960 --> 00:26:15.000 right, you will abs get back. You'd never never make it back. 292 00:26:17.000 --> 00:26:21.960 So yeah, it's an interesting conjecture, and the universe very different from the 293 00:26:22.079 --> 00:26:25.799 one we live in today than It's a horrifying thought, though, isn't it. 294 00:26:26.119 --> 00:26:30.240 Let's go visit that rock. Oh it's gone, yeah, and we 295 00:26:30.319 --> 00:26:33.880 can't get back. Not good, thank you, Jim. On a similar 296 00:26:36.319 --> 00:26:41.519 kind of playing field, Paul in Melbourne says there has been talked recently about 297 00:26:41.559 --> 00:26:45.000 the energy that causes the universe to expand coming from black holes. If this 298 00:26:45.200 --> 00:26:49.119 is so, then wouldn't we see the space time around or near a black 299 00:26:49.160 --> 00:26:53.920 hole expanding at a faster rate than that further away from black holes, for 300 00:26:55.000 --> 00:26:59.839 example, between galaxies or that in the spaces between the filaments of the cosmic 301 00:27:00.039 --> 00:27:06.799 web. Wouldn't the filaments of the cosmic web be expanding faster? And it's 302 00:27:06.839 --> 00:27:11.079 pretat data. Yeah, I'm just trying to remember what the mechanism wants that 303 00:27:11.359 --> 00:27:21.000 linked and quite get my head to it that linked black holes with the dark 304 00:27:21.160 --> 00:27:27.400 energy, which is what, you know, what is the thing that we 305 00:27:27.480 --> 00:27:33.599 think drives the expansion of the universe. Dark energy seems to be very much 306 00:27:33.640 --> 00:27:38.359 a property of space itself, a uniform property that that's the same wherever you 307 00:27:38.440 --> 00:27:45.400 look. So Paul's question is is an interesting one. So and I can't 308 00:27:45.480 --> 00:27:53.680 remember the exact link between the mechanisms within black holes and the dark energy, 309 00:27:55.039 --> 00:28:00.279 because yes, you know, it's an intuitive thought if if dark energy coming 310 00:28:00.319 --> 00:28:04.839 from black holes, then the region around black holes should be expanding more than 311 00:28:06.119 --> 00:28:10.799 the region elsewhere. But we already observe the fact that that doesn't happen. 312 00:28:11.599 --> 00:28:15.079 We do see space time distorted around black holes. But that's due to their 313 00:28:15.559 --> 00:28:23.960 gravitational attraction. That's the standard general relativity distortion of space time that we see, 314 00:28:25.640 --> 00:28:32.119 you know, whenever we find gravitational lenses, for example. So, 315 00:28:33.279 --> 00:28:36.240 as I said, the point about dark energy is, say it is a 316 00:28:36.400 --> 00:28:41.079 phenomenon that is a property of space. I would have to I'd have to 317 00:28:41.160 --> 00:28:48.559 look back at what I was reading up on the mechanism that feeds the energy 318 00:28:48.640 --> 00:28:52.559 of black holes into the space around them to be able to give an answer 319 00:28:52.640 --> 00:28:56.440 to pulse question. So I'm a bit embarrassed that I can't do that. 320 00:28:56.960 --> 00:29:00.480 I mean, it was about well, it must have been at least two 321 00:29:00.559 --> 00:29:03.480 months ago when we talked about this. Yeah, I guess, so I 322 00:29:03.559 --> 00:29:06.880 don't remember the conversation. I just yeah, I just can't recall it. 323 00:29:07.240 --> 00:29:11.359 Is it is that paper I don't think has been refuted, the one that 324 00:29:11.480 --> 00:29:17.279 suggests that maybe black holes could provide the origin of dark energy. And I 325 00:29:17.359 --> 00:29:21.799 wish I could there is a there's a there's a point about it which I'm 326 00:29:21.839 --> 00:29:26.319 just not not able to recover at the moment from the memory bikes. Yeah, 327 00:29:27.279 --> 00:29:30.440 I could have a quick look and see if I can find the article, 328 00:29:30.559 --> 00:29:34.920 but gosh, I don't know. There's yeah, there's there's plenty of 329 00:29:36.039 --> 00:29:38.039 articles about it, So which one do you pick? But yeah, it's 330 00:29:38.039 --> 00:29:42.920 certainly got a lot of interest at the time. Will continue. So we're 331 00:29:42.920 --> 00:29:47.880 talking, we're talking mid February when that first came. Yeah, so you 332 00:29:47.960 --> 00:29:52.559 know it's fair enough that at our age we've forgotten. I felt we remember 333 00:29:52.599 --> 00:29:56.559 the was there? Yes, yes, indeed, So Paul, I might 334 00:29:56.839 --> 00:30:00.480 try and look at that again and we might get back to if we don't 335 00:30:00.519 --> 00:30:07.119 forget. Thanks entire conversation. I'll put an asterisk next to his question. 336 00:30:07.319 --> 00:30:10.799 Follow up. All right, thank you, Paul, Thanks for sending in 337 00:30:10.880 --> 00:30:15.160 the question. This is Space Nuts Andrew Duncley here with Professor Fred Watson. 338 00:30:18.359 --> 00:30:26.559 Great Space Nuts. Okay Fred, a few more questions before we wrap it 339 00:30:26.680 --> 00:30:30.039 up. And this one comes from Western Australia and our good friend Rusty, 340 00:30:30.200 --> 00:30:34.039 actually, to be more specific, Rusty's wife. Hello, Space Nuts. 341 00:30:34.039 --> 00:30:40.039 It's Rusty and Donnybrook. My lovely wife Ally came up with a question about 342 00:30:40.920 --> 00:30:48.119 asteroids and she's seen a few movies with asteroid fields in them and wonders if 343 00:30:48.200 --> 00:30:52.920 they're realistic, how close do they get and how often do they collide, 344 00:30:55.160 --> 00:31:00.000 and I think I'm sure she'd love your answer. Cheers, Thanks, Rusty, 345 00:31:00.000 --> 00:31:04.960 we are Yeah, asteroids are not an uncommon topic of questions either, 346 00:31:06.759 --> 00:31:08.759 mainly the ones that are going to hit us or near nar hit us. 347 00:31:10.599 --> 00:31:14.440 But yeah, a different spin on it, so to speaking, and a 348 00:31:14.519 --> 00:31:18.759 good one too, great question, because we you know, when you look 349 00:31:18.799 --> 00:31:22.200 at depictions of the Solar System, the main asteroid belt, which sits between 350 00:31:22.240 --> 00:31:26.960 the orbits of Males and Jupiter, is always portrayed as being full of asteroids, 351 00:31:29.039 --> 00:31:36.599 asteroids everywhere in every direction. Whereas the bottom line here is, you 352 00:31:36.680 --> 00:31:41.400 know Douglas Adam's famous quotation, space is big. You will believe how big 353 00:31:41.480 --> 00:31:45.200 it is. Anyway, it's big. What was it? You might think 354 00:31:45.200 --> 00:31:47.519 it's a long way. You might stret a long way down the street to 355 00:31:47.599 --> 00:31:52.680 the chemist. That's right. Anyway, there is a lot of space between 356 00:31:52.759 --> 00:31:59.799 them. So, as witnessed by the fact that I can't remember how many 357 00:32:00.160 --> 00:32:06.759 is it must be this five. About eight or nine spacecraft have gone through 358 00:32:06.839 --> 00:32:15.279 the asteroid belt, including Galileo Cassini, two Voyagers to two Pioneers New Horizons. 359 00:32:15.200 --> 00:32:20.799 They've all gone through the asteroid belt and of course been completely unscathed. 360 00:32:21.880 --> 00:32:29.079 On having said that, the second part of rust wife's question, I'm sorry 361 00:32:29.079 --> 00:32:34.079 I didn't catch your name, But the second part is do they collide? 362 00:32:34.119 --> 00:32:37.880 And the answer is yes. From time to time they do, which we 363 00:32:37.160 --> 00:32:45.799 see usually as a plume of material coming from an asteroid that's being accidentally observed, 364 00:32:45.920 --> 00:32:50.680 usually because since part of the field of view of something else, so 365 00:32:50.960 --> 00:32:53.599 some nondescript asteroid will suddenly start looking like a comet. It will get a 366 00:32:53.640 --> 00:33:00.480 tale of material, a bit like Demorphus did after it was clouted by the 367 00:33:00.799 --> 00:33:07.319 Dart spacecraft. So you get this usually reasonably straight lined cloud of material which 368 00:33:07.440 --> 00:33:14.200 is interpreted as having been a collision between two asteroids. We think we've even 369 00:33:14.240 --> 00:33:20.240 observed one in the planetary system of another star. The star is Famulo. 370 00:33:20.359 --> 00:33:24.960 It's a bright star in our southern skies, and over a number of years 371 00:33:25.119 --> 00:33:30.920 that's been observed to have an object going around it. We covered this, 372 00:33:30.039 --> 00:33:34.480 I think a year or so ago Andrew, which was thought to be a 373 00:33:34.559 --> 00:33:39.839 planet. They gradually got fainter and eventually disappeared, And the thinking is that 374 00:33:40.000 --> 00:33:45.720 what we actually were looking at was the debris cloud from two large asteroids that 375 00:33:45.799 --> 00:33:51.880 it collided. That collided because that thing's vanished altogether now as the debris cloud 376 00:33:52.079 --> 00:33:59.440 disperses, so they do collide relatively rarely because the space between them is so 377 00:33:59.720 --> 00:34:02.119 it's big. Yeah, I mean, going back a few billion years, 378 00:34:02.160 --> 00:34:06.240 it was probably a lot more collisions. There's a lot more stuff out there 379 00:34:06.319 --> 00:34:08.599 to hit each other in close proximity. In fact, that we give that 380 00:34:08.760 --> 00:34:13.840 period a name, it's called the Late Heavy bombardment about three point eight billion 381 00:34:13.920 --> 00:34:16.800 years ago, when the place was full of debris charging around and bashing into 382 00:34:17.280 --> 00:34:22.679 other things, including Earth. Yeah, including Earth. That's right. Indeed, 383 00:34:23.719 --> 00:34:30.320 Thanks Rusty and spouse. Let's get let's go onto annex. Question from 384 00:34:30.840 --> 00:34:37.719 Renny all right, this is ready from West Hills, California, with another 385 00:34:37.880 --> 00:34:44.239 question. I'm trying to understand what space time is made out and why it 386 00:34:44.440 --> 00:34:50.440 bends when it interacts with matter. I envisioned space climb as an invisible energy 387 00:34:50.599 --> 00:34:54.800 force pushing against some object of matter, which is another form of energy, 388 00:34:55.199 --> 00:35:00.159 where they to find a balance, which is gravity. Am I correct? 389 00:35:01.639 --> 00:35:06.920 Yes? And the answer to your question is it's made up of space end 390 00:35:07.000 --> 00:35:10.519 time. Yeah, that's the trouble. Nobody really knows what space time is, 391 00:35:14.719 --> 00:35:20.039 but I can qualify that a little bit further because whatever it is, 392 00:35:20.239 --> 00:35:24.079 yeah, you know, we glibly talk about the fabric of spacetime bending under 393 00:35:24.400 --> 00:35:29.639 the action of mass. Renny is quite right. It's really hard to get 394 00:35:29.719 --> 00:35:34.920 your head around that because back in the eighteen eighties we got rid of the 395 00:35:35.039 --> 00:35:39.760 idea that there was an ether something that actually permeated space and allowed light to 396 00:35:40.360 --> 00:35:45.159 pass through a medium that would transmit light that got thrown out, and the 397 00:35:45.320 --> 00:35:51.639 consequence of that was actually the special theory of relativity, which says that you 398 00:35:51.719 --> 00:35:54.840 know you're in the speed of light is the same everywhere because the experiments, 399 00:35:54.960 --> 00:36:00.280 the Mikolson Morley experiment as it was called, to measure the ether relied on 400 00:36:00.400 --> 00:36:05.360 the fact that you should see the speed of light changing depending on what direction 401 00:36:05.400 --> 00:36:08.320 you're moving through the ether. And we're not moving through the ether, so 402 00:36:08.400 --> 00:36:13.760 the speed of light doesn't change. And that then brings up special theory of 403 00:36:13.840 --> 00:36:22.920 relativity. So we really don't know what it is. But I think you 404 00:36:22.079 --> 00:36:27.599 have to look at the big picture here, because the big picture says, 405 00:36:27.760 --> 00:36:35.480 well, there are two sort of pivotal theories on which we base our view 406 00:36:35.519 --> 00:36:42.719 of reality. General relativity, which works incredibly well for things on a large 407 00:36:42.760 --> 00:36:47.039 scale and quantum mechanics, which works incredibly well for things on a small scale. 408 00:36:47.519 --> 00:36:52.119 But the two are incompatible. They don't sort of sit together, and 409 00:36:52.360 --> 00:36:59.119 that sparks back in Einstein's day. Actually the quest for a theory of quantum 410 00:36:59.199 --> 00:37:04.079 gravity that would allow us to unite these two theories, which we're still looking 411 00:37:04.199 --> 00:37:12.880 for. But one of the themes that I think is addressed by quantum gravitists, 412 00:37:12.920 --> 00:37:16.000 if I can put them that way, people theoretical physicists who work on 413 00:37:16.119 --> 00:37:21.760 this. One of the themes is that we're missing something, and what we're 414 00:37:21.800 --> 00:37:29.119 missing is a more fundamental theory of space and time that underpins what we see 415 00:37:29.400 --> 00:37:32.199 as space and time. In other words, there might be something else that 416 00:37:32.960 --> 00:37:38.880 from which space and time emerge and hence space time. Many quantum theorists in 417 00:37:38.960 --> 00:37:43.760 the last twenty years have proposed that, and most of the theories I mean 418 00:37:43.840 --> 00:37:47.159 string theories one of those. It's that sort of idea that there's something there 419 00:37:49.199 --> 00:37:53.800 that underpins what we observe in relativity and in quantum mechanics, and a kind 420 00:37:53.840 --> 00:38:01.440 of deeper version of reality which may include additional dimensions. There is some recent 421 00:38:01.519 --> 00:38:05.840 work that's being done on this, which we might talk about in coming weeks. 422 00:38:05.880 --> 00:38:13.719 Andrew, that once again highlights that there might be this hidden reality beneath 423 00:38:13.800 --> 00:38:19.440 space and time, which how do we probe it? That's the problem and 424 00:38:19.760 --> 00:38:22.639 the suggestions that are being put forward by how we might deal with that in 425 00:38:22.760 --> 00:38:30.400 a real situation, how we might actually try and peer underneath the gossom avail. 426 00:38:30.159 --> 00:38:36.360 It's not gossom avail, it's a curse relativity. And on the other 427 00:38:36.440 --> 00:38:40.239 side, quantum mechanics, also known as the banking industry. The banking industry 428 00:38:40.239 --> 00:38:44.880 has got that as well as different realities. In fact, yes, I 429 00:38:44.960 --> 00:38:49.039 think there are many places in the world where you can put to different realities. 430 00:38:50.199 --> 00:38:53.440 Yeah, indeed, thank you, Renny, and hope that helped somewhat 431 00:38:53.920 --> 00:39:00.760 now adequately. Now, finally we'll go to David, who is from Huntsville, 432 00:39:00.800 --> 00:39:04.480 Alabama. First of all, I'm a huge fan of the show and 433 00:39:04.519 --> 00:39:08.079 appreciate what you guys do to put new wrinkles in my brain. I look 434 00:39:08.119 --> 00:39:13.320 forward to each Thursday for my space nuts fixed. My question is if a 435 00:39:13.480 --> 00:39:19.960 photon does not experience time after it's been emitted, and the universe is expanding 436 00:39:20.039 --> 00:39:23.960 greater than the speed of light, assuming the photon has an unimpeded line straight 437 00:39:24.039 --> 00:39:29.119 towards the edge of the universe. Is the photon essentially trapped in time at 438 00:39:29.239 --> 00:39:32.519 that point? Thanks keep up the great work kind of relates to a question 439 00:39:32.599 --> 00:39:37.519 we had earlier. It does yet, and it presupposes the universe as an 440 00:39:37.639 --> 00:39:45.840 edge, which we don't think it has. We don't know what it's got 441 00:39:45.880 --> 00:39:51.079 will beget us an edge. It's got a banking industry surrounding it, a 442 00:39:51.239 --> 00:39:59.039 pique veil. So if but if the photon, you know, to the 443 00:39:59.119 --> 00:40:02.480 photons always traveling through the universe at the speed of light. Now, the 444 00:40:02.639 --> 00:40:12.400 fact that it's the source of the photon and its destination are separating, are 445 00:40:12.480 --> 00:40:15.920 being separated by the expansion of the universe greater than the speed of light, 446 00:40:16.719 --> 00:40:21.840 doesn't matter to the photon. It just keeps ongoing. The fact that its 447 00:40:21.920 --> 00:40:25.320 target is moving away from it faster than it's ever going to get there is 448 00:40:25.360 --> 00:40:30.480 not a concern to the photon. It will still not experience the passage of 449 00:40:30.559 --> 00:40:35.159 time, which is exactly what David said. That's what we think is the 450 00:40:35.280 --> 00:40:42.199 case. We'll just keep going forever. I suppose, in a sense it's 451 00:40:42.480 --> 00:40:47.000 the scenario that he he mentioned that it will just keep on passing through space 452 00:40:47.880 --> 00:40:52.679 and infinitem because it's destination is not good. He is always going to be 453 00:40:52.800 --> 00:41:00.719 further away that it will reach until the big rip an escape, yeah maybe, 454 00:41:00.559 --> 00:41:05.559 or if there's a big rip, there'll be tidal forces beyond imagination that 455 00:41:05.599 --> 00:41:10.119 would probably disturb everything as it. Yes, that's the big rip. There's 456 00:41:10.159 --> 00:41:14.920 got consequences that we can't really envisage it at the moment, but it's definitely 457 00:41:15.000 --> 00:41:20.039 not nice and it reminds me of that famous song I'm a Photon and I'm 458 00:41:20.119 --> 00:41:22.480 okay, I Glow all day and I Glow all night and I Glow all 459 00:41:22.559 --> 00:41:30.719 day stealing from Monty Python. Yeah, not quite, but nearly works as 460 00:41:30.760 --> 00:41:37.760 well as the original Lumberjack song. Thank you, David. It's so great 461 00:41:37.800 --> 00:41:40.039 to hear from you, and thanks to everyone who's sending questions. It's nice 462 00:41:40.039 --> 00:41:45.159 to fill an episode with audience questions. And we've got a whole fresh batch 463 00:41:45.280 --> 00:41:47.480 like one minute before we started, so that was that was good, and 464 00:41:47.559 --> 00:41:52.519 that's why some of them sort of caught us out of left field because we 465 00:41:52.679 --> 00:41:59.000 did what we usually do and went in totally unprepared. Sometimes works, So 466 00:41:59.480 --> 00:42:00.840 if you do have a question for us, of course, send it to 467 00:42:01.000 --> 00:42:05.119 us, because that's what it's all about. We love to interact with you 468 00:42:05.400 --> 00:42:08.239 and we love to hear your voices. So where you can record through our 469 00:42:08.280 --> 00:42:13.159 website, space nuts podcast dot com or space nuts dot io. Click on 470 00:42:13.239 --> 00:42:15.719 the AMA link and you can record a question there, or send us a 471 00:42:15.760 --> 00:42:19.400 text question, or you can just hit the tab on the right hand side 472 00:42:19.440 --> 00:42:22.519 at the home page send us your voice message. And as long as you've 473 00:42:22.519 --> 00:42:27.239 got a smart device or a computer or something dumber than that that's got a 474 00:42:27.320 --> 00:42:30.159 microphone, you can send us a question. But we're taking text and audio 475 00:42:30.280 --> 00:42:35.599 questions all the time. The more the merrier. And yes, don't forget 476 00:42:35.599 --> 00:42:38.760 the hypotheticals. I love those hypotheticals. Fred, we're wrapping it up for 477 00:42:38.880 --> 00:42:45.039 you yet another. It's a milestone. It is actually three hundred and fifty. 478 00:42:45.280 --> 00:42:47.559 Kind of let that slip through to keep it. I'll believe it. 479 00:42:47.960 --> 00:42:52.559 Yeah, fifty three hundred and fifty. Oh my gosh, it seems like 480 00:42:52.760 --> 00:42:57.559 only six months ago we did episode. Probably a year ago we did episode 481 00:42:57.639 --> 00:43:00.920 three hundred. That's a bit, wouldn't it, Yes, that will be 482 00:43:00.079 --> 00:43:07.920 I have to be near a year would yes? That's a calculation there the 483 00:43:07.000 --> 00:43:15.599 words we should get a life really come to by. Maybe we should thank 484 00:43:15.679 --> 00:43:19.800 you Fred as always good good to tell Andrew take care all right, We'll 485 00:43:19.840 --> 00:43:22.639 catch you soon. Fred Watson, astronomer at large part of the team here 486 00:43:22.800 --> 00:43:29.199 adds Space Nuts and back at Space Nuts HQ, we say thanks to Hugh 487 00:43:29.440 --> 00:43:34.599 for reasons we cannot comprehend, but anyway, thank you anyway, and from 488 00:43:34.639 --> 00:43:37.840 me Andrew Dunkley, thanks for joining us each and every weekend for this latest 489 00:43:37.880 --> 00:43:42.760 episode. We'll catch you on the very next one on Space Nuts. Bye 490 00:43:42.800 --> 00:43:50.519 bye. You'll be listening to the Space Nuts podcast, available at Apple Podcasts, 491 00:43:50.760 --> 00:43:55.079 Google Podcasts, Spotify, iHeart Radio, or your favorite podcast player. 492 00:43:55.320 --> 00:44:00.519 You can also stream on demand at bides dot com. This is been another 493 00:44:00.599 --> 00:44:02.519 quality podcast production from sites dot com.