WEBVTT 0 00:00:00.320 --> 00:00:02.360 Andrew Dunkley: Hello, thanks for joining us. This is Space 1 00:00:02.360 --> 00:00:04.960 Nuts. My name is Andrew Dunkley, and we're 2 00:00:04.960 --> 00:00:07.080 here to talk astronomy and space science. And 3 00:00:07.080 --> 00:00:09.480 on this episode, we are going to look at a 4 00:00:09.480 --> 00:00:12.400 study into Jupiter's role in shaping 5 00:00:12.480 --> 00:00:15.360 our solar system. What shape is that? 6 00:00:15.919 --> 00:00:18.870 It's rhomboid. No, we don't know. we're also 7 00:00:18.870 --> 00:00:21.300 going to look at a, white dwarf star that's 8 00:00:21.300 --> 00:00:23.940 chowing down on a planetesimal. Sounds 9 00:00:23.940 --> 00:00:26.390 appetizing. observing a rapidly 10 00:00:26.390 --> 00:00:28.510 developing ring system, and it's not far 11 00:00:28.510 --> 00:00:31.180 away. And if we've got time, an exoplanet 12 00:00:31.330 --> 00:00:33.890 that in inverted commas may 13 00:00:34.450 --> 00:00:37.330 be a life candidate. That's all coming up on 14 00:00:37.490 --> 00:00:40.330 space nuts. 15 seconds. Guidance is 15 00:00:40.330 --> 00:00:42.770 internal. 10, 9. 16 00:00:43.330 --> 00:00:46.094 Ignition sequence start. space nuts. 5, 4, 17 00:00:46.166 --> 00:00:48.974 3, 2. 1, 2, 3, 4, 5, 5, 18 00:00:49.046 --> 00:00:50.450 4, 3, 2, 1. 19 00:00:50.530 --> 00:00:51.650 Jonti Horner: Space nuts. 20 00:00:51.730 --> 00:00:54.650 Andrew Dunkley: Astronauts report it feels good. And it's 21 00:00:54.650 --> 00:00:56.530 good to have Jonti Horner back with us again. 22 00:00:56.530 --> 00:00:58.770 Professor of astrophysics at the University 23 00:00:58.930 --> 00:01:01.010 of Southern Queensland. Hi, Jonti. 24 00:01:01.340 --> 00:01:02.380 Jonti Horner: Good evening. How are you going? 25 00:01:02.620 --> 00:01:04.460 Andrew Dunkley: I am well. Good to see you. 26 00:01:04.860 --> 00:01:06.980 Jonti Horner: Oh, it's good to be back. Although I'm 27 00:01:06.980 --> 00:01:08.820 admittedly a bit of a zombie, so I warn 28 00:01:08.820 --> 00:01:10.420 everybody, I've had less sleep than I should 29 00:01:10.420 --> 00:01:11.900 have done in the last couple of days because 30 00:01:11.900 --> 00:01:14.730 of the weather. we had some weather happen on 31 00:01:14.730 --> 00:01:17.280 Sunday, which led to the power here being 32 00:01:17.280 --> 00:01:19.680 knocked out for 24 hours during a mini heat 33 00:01:19.680 --> 00:01:21.520 wave. So I didn't get much sleep then. And 34 00:01:21.520 --> 00:01:23.520 then this morning I've got a colleague from 35 00:01:23.520 --> 00:01:25.480 Japan visiting, so I had to pick him, his 36 00:01:25.480 --> 00:01:27.200 wife and their two lovely daughters up from 37 00:01:27.200 --> 00:01:29.660 Brisbane Airport. So I've had six hours of 38 00:01:29.660 --> 00:01:31.860 driving today off the back of two nights of 39 00:01:31.860 --> 00:01:34.420 not much sleep. So if I seem less coherent 40 00:01:34.420 --> 00:01:35.900 than normal, and I appreciate I'm normally 41 00:01:35.900 --> 00:01:38.300 not that coherent to begin with, you know 42 00:01:38.300 --> 00:01:39.940 why, of course. 43 00:01:39.940 --> 00:01:42.200 Andrew Dunkley: Yes, we've all been there. we've had dreadful 44 00:01:42.200 --> 00:01:44.160 weather here too. But it hasn't been the 45 00:01:44.160 --> 00:01:46.360 extreme heat, it's been the extreme wind. 46 00:01:47.140 --> 00:01:49.600 I got woken up, last night about 47 00:01:49.600 --> 00:01:52.480 1am by the Fly, screens rattling. It 48 00:01:52.480 --> 00:01:55.030 was so windy. Yes, they, they were just 49 00:01:55.030 --> 00:01:56.880 shuddering. And I thought, I can't live with 50 00:01:56.880 --> 00:01:57.040 this. 51 00:01:57.040 --> 00:01:57.840 Jonti Horner: So I went outside. 52 00:01:58.000 --> 00:02:00.680 Andrew Dunkley: It was freezing cold, supposed to be late 53 00:02:00.680 --> 00:02:03.600 spring here, and I 54 00:02:03.680 --> 00:02:05.600 just jammed some wood chips 55 00:02:06.720 --> 00:02:09.440 into the. I just went off to the 56 00:02:09.440 --> 00:02:11.400 garden and grabbed some mulch and shoved it 57 00:02:11.400 --> 00:02:14.160 in the wind in, in the fly screens to stop 58 00:02:14.160 --> 00:02:14.880 them rattling. 59 00:02:14.880 --> 00:02:15.520 Jonti Horner: It worked. 60 00:02:15.840 --> 00:02:17.760 Andrew Dunkley: I've done it better during the day, but, 61 00:02:17.710 --> 00:02:19.430 well, that's just Been ridiculous. 62 00:02:19.510 --> 00:02:21.510 Jonti Horner: I know your parents. I mean having said that 63 00:02:21.510 --> 00:02:23.030 we had heat wave conditions and couldn't 64 00:02:23.030 --> 00:02:25.170 sleep because of the heat, I'm happ confess 65 00:02:25.170 --> 00:02:26.850 that I've had the wood serve on today because 66 00:02:26.850 --> 00:02:29.650 having had 36, 38 degrees so 67 00:02:29.650 --> 00:02:32.210 that's around 100 for our American friends 68 00:02:33.090 --> 00:02:36.010 last few days. Today has been a toasty kind 69 00:02:36.010 --> 00:02:38.950 of 15 degrees. and we've got a rain event 70 00:02:38.950 --> 00:02:41.680 happening. so we've had everything in the 71 00:02:41.680 --> 00:02:44.240 last week we've had kind of almost tornadic 72 00:02:44.240 --> 00:02:46.520 storms, we've had hailstones the size of your 73 00:02:46.520 --> 00:02:48.470 fists, we've had under a kilometer an hour 74 00:02:48.470 --> 00:02:50.950 gusts and now we've got random cold that 75 00:02:50.950 --> 00:02:53.110 makes me feel like I'm back in the uk. So 76 00:02:53.350 --> 00:02:55.270 yeah, all happening. And this is why 77 00:02:55.270 --> 00:02:56.790 Australia is an interesting place to live 78 00:02:56.790 --> 00:02:58.310 even to the extent that with the 79 00:02:58.310 --> 00:03:00.630 thunderstorms. We had got an email through 80 00:03:00.630 --> 00:03:02.430 yesterday that our wonderful observatory, 81 00:03:02.430 --> 00:03:04.190 Queensland's only professional astronomical 82 00:03:04.190 --> 00:03:06.270 observatory in Mount Kent was closed 83 00:03:06.270 --> 00:03:07.910 yesterday. We weren't allowed to go there 84 00:03:08.070 --> 00:03:10.830 because there was a bushfire within 10km of 85 00:03:10.830 --> 00:03:12.870 it that had been sparked by the lightning 86 00:03:12.870 --> 00:03:15.270 from the storms and fanned by the heat wave 87 00:03:15.630 --> 00:03:18.050 in a place that got lightning but no rain. So 88 00:03:18.050 --> 00:03:19.790 ah, it's all happening here. 89 00:03:20.270 --> 00:03:23.030 Andrew Dunkley: Yes, dry storms are not uncommon where I am. 90 00:03:23.030 --> 00:03:25.970 We we do get quite a few storms every year 91 00:03:25.970 --> 00:03:28.850 with lightning and thunder and nothing else. 92 00:03:28.890 --> 00:03:31.180 and they, yeah, they're very well known for 93 00:03:31.180 --> 00:03:32.780 sparking bushfires. 94 00:03:32.780 --> 00:03:33.060 Jonti Horner: Yeah. 95 00:03:33.060 --> 00:03:34.740 So while we're on the diversion of the 96 00:03:34.740 --> 00:03:36.500 weather, actually I'll apologize for Maya the 97 00:03:36.500 --> 00:03:38.020 dog chirping in the background but my 98 00:03:38.020 --> 00:03:40.140 partner's just got home. But we're also 99 00:03:40.140 --> 00:03:42.620 sitting here with an incredibly heartbreaking 100 00:03:42.620 --> 00:03:45.440 record, record breaking storm in the 101 00:03:45.440 --> 00:03:48.360 Caribbean. Yes, I know she's just come 102 00:03:48.360 --> 00:03:50.240 home. Thank you for joining me with the 103 00:03:50.240 --> 00:03:53.030 podcast Happy Dog. but yeah, there's 104 00:03:53.110 --> 00:03:55.030 borderline record breaking storm in the 105 00:03:55.030 --> 00:03:57.430 Caribbean which is going to be a Category 5 106 00:03:57.430 --> 00:03:59.660 hurricane hitting Jamaica and doing a, ah, 107 00:04:00.230 --> 00:04:01.830 hell of a lot of damage. And it's one of 108 00:04:01.830 --> 00:04:03.670 these that from a scientist point of view, 109 00:04:03.990 --> 00:04:06.040 fascinating watching it looking at the radar 110 00:04:05.990 --> 00:04:08.670 footage and all the satellite footage and on 111 00:04:08.670 --> 00:04:10.230 one hand you've got this thing of incredible 112 00:04:10.230 --> 00:04:12.630 exceptional beauty and on the other hand the 113 00:04:12.630 --> 00:04:14.970 devastation it's going to cause. So the 114 00:04:14.970 --> 00:04:16.770 people in the, in the firing line for that. 115 00:04:16.770 --> 00:04:18.690 Andrew Dunkley: Yeah, I saw the satellite images this 116 00:04:18.690 --> 00:04:20.370 afternoon. It is enormous. 117 00:04:20.370 --> 00:04:23.290 Jonti Horner: Yeah, you look at the false color one 118 00:04:23.290 --> 00:04:24.890 with the color of the clouds which is an 119 00:04:24.890 --> 00:04:26.610 indication of the severity of the storm and 120 00:04:26.610 --> 00:04:28.530 the shape and it's the kind of thing that you 121 00:04:28.530 --> 00:04:30.770 only see with the strongest storms we've ever 122 00:04:30.770 --> 00:04:33.250 seen, typically in the Pacific. So for this 123 00:04:33.250 --> 00:04:36.250 thing to not only be happening in the 124 00:04:36.250 --> 00:04:38.960 Atlantic, which is less common, but 125 00:04:38.960 --> 00:04:41.720 to be, you know, crosshairs on Jamaica, 126 00:04:41.720 --> 00:04:43.760 which has had a bit of a charmed life with 127 00:04:43.760 --> 00:04:45.560 some sacks of the high mountains that tend to 128 00:04:45.560 --> 00:04:47.920 bounce and go around a bit. This one looks 129 00:04:47.920 --> 00:04:49.240 like it's not so much going to bounce a 130 00:04:49.240 --> 00:04:49.760 splat. 131 00:04:49.920 --> 00:04:52.770 Andrew Dunkley: So yeah, when we were in Panama earlier 132 00:04:52.770 --> 00:04:55.580 this year, we did the Panama Canal and 133 00:04:55.680 --> 00:04:57.750 they were saying that they never get 134 00:04:57.750 --> 00:04:58.910 hurricanes ever. 135 00:05:00.190 --> 00:05:02.950 Jonti Horner: Too equatorial is my understanding. You need 136 00:05:02.950 --> 00:05:04.790 to be far enough away from the equator to get 137 00:05:04.790 --> 00:05:06.960 enough spin so. So it's very rare that you 138 00:05:06.960 --> 00:05:09.000 get storms getting right up to the equator 139 00:05:09.560 --> 00:05:11.800 because coriolis force and things like that. 140 00:05:11.880 --> 00:05:13.680 Andrew Dunkley: Yeah, yeah, it's interesting, isn't it? 141 00:05:13.680 --> 00:05:16.600 Very interesting. Okay, we better get 142 00:05:16.600 --> 00:05:19.120 on with what we came here to get on with. And 143 00:05:19.120 --> 00:05:22.110 we're going to start with a study that's 144 00:05:22.110 --> 00:05:24.510 been released into Jupiter's role in shaping 145 00:05:24.510 --> 00:05:26.750 the solar system. Now I do recall Fred 146 00:05:26.750 --> 00:05:29.740 mentioning that Jupiter, if Jupiter 147 00:05:29.740 --> 00:05:32.580 didn't exist we wouldn't. And this study 148 00:05:32.900 --> 00:05:35.300 basically adds a lot of fuel to that claim. 149 00:05:35.780 --> 00:05:38.500 Jonti Horner: It does. Now where Fred said, 150 00:05:38.660 --> 00:05:40.860 Fred and other people talk about if Jupiter 151 00:05:40.860 --> 00:05:43.420 didn't exist then we probably wouldn't. Ties 152 00:05:43.420 --> 00:05:45.780 into something that's a pretty big 153 00:05:46.180 --> 00:05:49.140 myth in science communication, Ansel in 154 00:05:49.620 --> 00:05:51.660 science papers and stuff, which is the idea 155 00:05:51.660 --> 00:05:54.630 of Jupiter shielding us from impacts. And my 156 00:05:54.790 --> 00:05:57.190 most favorite piece of research I ever did in 157 00:05:57.190 --> 00:05:58.910 my career is proving that to be a lot of 158 00:05:58.910 --> 00:06:00.650 cobblers and it's actually a lot more 159 00:06:00.650 --> 00:06:02.810 complicated. Jupiter throws things at us as 160 00:06:02.810 --> 00:06:05.090 well as protecting us. So I've always got a 161 00:06:05.090 --> 00:06:07.290 bit of an eye on any study that says, hey 162 00:06:07.290 --> 00:06:09.330 guys, if Jupiter wasn't there, neither would 163 00:06:09.330 --> 00:06:11.930 we. But this is a really interesting one that 164 00:06:11.930 --> 00:06:14.090 looks an entirely different aspect of 165 00:06:14.090 --> 00:06:16.810 Jupiter, which is the role that Jupiter 166 00:06:16.810 --> 00:06:18.650 played on the formation and evolution of the 167 00:06:18.650 --> 00:06:21.010 early solar system, the formation of the 168 00:06:21.010 --> 00:06:23.050 planets. And I've actually been teaching 169 00:06:23.050 --> 00:06:25.010 planet formation this week to my undergrad 170 00:06:25.010 --> 00:06:27.630 students. I've just, prior to recording this, 171 00:06:27.790 --> 00:06:29.870 had a two hour tutorial with them where I've 172 00:06:29.870 --> 00:06:31.910 been talking about planet formation and 173 00:06:31.910 --> 00:06:34.910 brought this story up because it 174 00:06:34.910 --> 00:06:37.910 really highlights the fact that when we 175 00:06:37.910 --> 00:06:40.590 often see in documentaries and the stuff we 176 00:06:40.590 --> 00:06:43.390 get taught at school, we get the impression 177 00:06:43.390 --> 00:06:45.750 that everything's solved, that we know the 178 00:06:45.750 --> 00:06:47.810 answers, that we know full well how the 179 00:06:47.810 --> 00:06:49.890 planets formed in microscopic detail and 180 00:06:49.890 --> 00:06:52.010 we've got everything figured out and the 181 00:06:52.010 --> 00:06:54.410 Reality is that we haven't. We have a really 182 00:06:54.410 --> 00:06:57.370 good broad picture and we're getting better 183 00:06:57.370 --> 00:06:59.090 and better at understanding the processes 184 00:06:59.090 --> 00:07:01.130 that went on. But there's still a lot to 185 00:07:01.130 --> 00:07:02.890 learn. And part of that is that while we've 186 00:07:02.890 --> 00:07:04.890 known the solar system since the year dot, 187 00:07:05.130 --> 00:07:07.330 we've only known other planetary systems for 188 00:07:07.330 --> 00:07:10.090 the last 30 years. And in reality we're still 189 00:07:10.090 --> 00:07:11.770 learning an awful lot about the planetary 190 00:07:11.770 --> 00:07:14.490 systems we find elsewhere. And learning about 191 00:07:14.490 --> 00:07:16.490 them is cool and all, but it also gives us 192 00:07:16.490 --> 00:07:18.570 insights that help us better understand our 193 00:07:18.570 --> 00:07:20.980 planetary system and how it formed. And that 194 00:07:20.980 --> 00:07:23.900 ties into this because the more we 195 00:07:23.900 --> 00:07:25.900 study those other planetary systems, the more 196 00:07:25.900 --> 00:07:27.660 we're getting observations of really 197 00:07:27.660 --> 00:07:30.620 beautiful things like planetary systems that 198 00:07:30.620 --> 00:07:31.980 are in formation, where you've got a 199 00:07:31.980 --> 00:07:34.260 protoplanetary disk. And we're getting these 200 00:07:34.260 --> 00:07:37.060 gorgeous images from things like the 201 00:07:37.220 --> 00:07:39.420 ALMA array, the Ataccama Large Millimeter 202 00:07:39.420 --> 00:07:42.180 Array that shows disks of planet 203 00:07:42.180 --> 00:07:44.460 forming material around stars with gaps in 204 00:07:44.460 --> 00:07:46.990 them and ripples in them and bands in them, 205 00:07:46.990 --> 00:07:49.470 and all these beautiful structures. And some 206 00:07:49.470 --> 00:07:50.990 of these have been previous astronomy. 207 00:07:50.990 --> 00:07:53.710 Picture of the days where this ties into the 208 00:07:53.710 --> 00:07:56.030 solar system is if you imagine that kind of 209 00:07:56.030 --> 00:07:58.670 stereotypical image of a 210 00:07:58.670 --> 00:08:00.950 protoplanetary disk, a disk of gas and dust 211 00:08:00.950 --> 00:08:03.590 around a young star like the sun, where 212 00:08:03.590 --> 00:08:05.710 material is feeding in through that disk to 213 00:08:05.710 --> 00:08:08.030 the star. So while the gas and dust is 214 00:08:08.030 --> 00:08:09.630 orbiting the star, there is this kind of 215 00:08:09.630 --> 00:08:12.190 sense of inward motion where the stars kind 216 00:08:12.190 --> 00:08:14.340 of nominating at the inner edge of the disk, 217 00:08:14.340 --> 00:08:16.020 materials falling in, and more material from 218 00:08:16.020 --> 00:08:18.700 outside flowing in to replace it. Yeah, and 219 00:08:18.780 --> 00:08:21.060 some of the models of the formation of the 220 00:08:21.060 --> 00:08:23.140 solar system struggle to make the terrestrial 221 00:08:23.140 --> 00:08:26.060 planets as a result of that. Because the 222 00:08:26.140 --> 00:08:27.900 material in the inner solar system is 223 00:08:27.900 --> 00:08:30.180 destined to fall onto M the star. And how do 224 00:08:30.180 --> 00:08:32.300 you stop that happening to let that material 225 00:08:32.300 --> 00:08:35.020 hang around to actually form into planets? 226 00:08:35.500 --> 00:08:37.740 Now it's been pretty well established for a 227 00:08:37.740 --> 00:08:39.700 long time that the first planet that formed 228 00:08:39.700 --> 00:08:41.380 in the solar system and got to a good size 229 00:08:41.380 --> 00:08:43.970 was Jupiter. And there's good reasons for 230 00:08:43.970 --> 00:08:46.250 that. It formed far enough away from the sun 231 00:08:46.250 --> 00:08:48.930 that the temperature was cold enough that the 232 00:08:48.930 --> 00:08:51.920 disk was rich in ice, which at, the 233 00:08:51.920 --> 00:08:53.440 distance the Earth is from the sun, all that 234 00:08:53.440 --> 00:08:55.870 ice would be gas. when you're forming solid 235 00:08:55.870 --> 00:08:57.910 objects, you need solid objects to feed from. 236 00:08:58.230 --> 00:08:59.910 And so when you've got a lot of ice, you've 237 00:08:59.910 --> 00:09:01.830 got a lot more solids. So things grow 238 00:09:01.830 --> 00:09:04.550 quicker, there's a lot more to eat. And it's 239 00:09:04.550 --> 00:09:06.470 only when you get to about 10 or 12 times the 240 00:09:06.470 --> 00:09:08.030 Mass of the Earth that You're massive enough 241 00:09:08.030 --> 00:09:10.560 to effectively start gobbling up the gas as 242 00:09:10.560 --> 00:09:13.080 well. So Jupiter formed beyond this point 243 00:09:13.080 --> 00:09:14.720 called the snow line, where there's a lot 244 00:09:14.720 --> 00:09:17.400 more solid material. It got to grow really 245 00:09:17.400 --> 00:09:20.040 quickly. It grew quicker than things further 246 00:09:20.040 --> 00:09:21.520 out because the further out you go, the 247 00:09:21.520 --> 00:09:23.280 slower things happen. So Jupiter was very 248 00:09:23.280 --> 00:09:25.720 much in the sweet spot, grew really quickly 249 00:09:25.720 --> 00:09:27.480 and eventually got big enough that it started 250 00:09:27.480 --> 00:09:29.600 clearing the gas and the dust it could gather 251 00:09:29.600 --> 00:09:32.000 the gas as well. And it opened up a gap in 252 00:09:32.000 --> 00:09:34.410 the disk. And that's very analogous to what 253 00:09:34.410 --> 00:09:36.090 we're seeing with these beautiful images from 254 00:09:36.090 --> 00:09:38.780 ALMA places like this. So the team of 255 00:09:38.780 --> 00:09:41.340 researchers behind this work have run some 256 00:09:41.340 --> 00:09:44.300 really in depth computer modeling of the 257 00:09:44.300 --> 00:09:46.220 formation of the solar system formation of 258 00:09:46.220 --> 00:09:48.700 Jupiter, and showed that when Jupiter opens 259 00:09:48.700 --> 00:09:51.540 up the gap in the disk, its gravity will 260 00:09:51.540 --> 00:09:53.420 also have an impact on the inner solar 261 00:09:53.420 --> 00:09:55.900 system. It'll effectively create the 262 00:09:55.900 --> 00:09:58.100 gravitational equivalent of speed bumps, 263 00:09:58.260 --> 00:10:00.140 creating areas where the dust that's 264 00:10:00.140 --> 00:10:02.990 spiraling inwards can pile up and be 265 00:10:02.990 --> 00:10:05.290 stopped from traveling further in. 266 00:10:05.370 --> 00:10:08.290 Effectively. It also creates 267 00:10:08.290 --> 00:10:10.370 a gap between the in run out of solar system 268 00:10:10.370 --> 00:10:12.890 that nothing crosses because if anything gets 269 00:10:12.890 --> 00:10:15.460 in that gap, Jupiter noms on it. And that's 270 00:10:15.460 --> 00:10:17.780 really interesting because some studies that 271 00:10:17.780 --> 00:10:19.620 have looked at primordial material we've 272 00:10:19.620 --> 00:10:21.940 found from in the solar system suggests that 273 00:10:21.940 --> 00:10:23.540 there is a bit of a chemical difference 274 00:10:23.540 --> 00:10:25.220 between material that formed in the inner 275 00:10:25.220 --> 00:10:27.270 solar system and material that formed in the 276 00:10:27.270 --> 00:10:29.880 outer solar system. So this gap 277 00:10:29.880 --> 00:10:32.640 dividing the two gives a natural way for that 278 00:10:32.640 --> 00:10:35.360 to happen. But the really big exciting result 279 00:10:35.360 --> 00:10:38.120 from this is really that modeling of 280 00:10:38.440 --> 00:10:40.600 the structure that Jupiter would have imposed 281 00:10:40.600 --> 00:10:42.760 on the inner solar system. These kind of pile 282 00:10:42.760 --> 00:10:44.520 up regions where you get more m dust and 283 00:10:44.520 --> 00:10:47.200 debris than normal, the structures that, that 284 00:10:47.200 --> 00:10:49.240 would carve out ripples in the disk 285 00:10:49.240 --> 00:10:51.440 effectively and how that would then 286 00:10:51.440 --> 00:10:53.120 contribute to the formation of the 287 00:10:53.120 --> 00:10:55.650 terrestrial planets. and therefore suggesting 288 00:10:55.650 --> 00:10:57.930 that not only did Jupiter help the 289 00:10:57.930 --> 00:11:00.050 terrestrial planets form by creating sweet 290 00:11:00.050 --> 00:11:02.410 spots where material could pile up, but it 291 00:11:02.410 --> 00:11:04.090 may also have had a really strong influence 292 00:11:04.090 --> 00:11:06.170 on the architecture of the inner solar system 293 00:11:06.650 --> 00:11:08.650 by setting where the planets would form, 294 00:11:09.210 --> 00:11:11.570 which then would go through a bit of a 295 00:11:11.570 --> 00:11:13.610 randomization phase as everything collides 296 00:11:13.610 --> 00:11:15.770 with each other. But it kind of possibly set 297 00:11:15.770 --> 00:11:18.370 the blueprint for the inner solar system. And 298 00:11:18.370 --> 00:11:20.530 therefore, if Jupiter hadn't formed where it 299 00:11:20.530 --> 00:11:22.990 did and how it did, the Earth would look 300 00:11:22.990 --> 00:11:24.510 very, very different and we might not be 301 00:11:24.510 --> 00:11:24.790 here. 302 00:11:25.030 --> 00:11:27.740 Andrew Dunkley: Yeah, it's truly fascinating. And 303 00:11:27.900 --> 00:11:30.890 when you look at other systems that 304 00:11:30.890 --> 00:11:33.410 we've discovered, exoplanet solar systems, 305 00:11:33.960 --> 00:11:36.640 ours is starting to look a little bit more 306 00:11:36.640 --> 00:11:39.570 unusual than normal. and 307 00:11:39.570 --> 00:11:40.770 Jupiter may be the reason. 308 00:11:41.330 --> 00:11:43.050 Jonti Horner: It could well be. And it's one of those 309 00:11:43.050 --> 00:11:45.050 things, I'm reminded of the Monty Python 310 00:11:45.050 --> 00:11:47.040 thing. I think it's in Life of Brian, where 311 00:11:47.040 --> 00:11:48.120 you've got that thing of we're all 312 00:11:48.120 --> 00:11:50.840 individuals. Yes, we're. No, we're not. I'm 313 00:11:50.840 --> 00:11:53.280 not. Every 314 00:11:53.280 --> 00:11:55.200 planetary system is going to be unique 315 00:11:55.520 --> 00:11:58.320 because it is influenced by 316 00:11:58.480 --> 00:12:01.240 such a wide variety of things going on. Even 317 00:12:01.240 --> 00:12:03.000 the stars that form in the local 318 00:12:03.000 --> 00:12:04.640 neighborhood, whittling it away from the 319 00:12:04.640 --> 00:12:07.160 outside, it all starts going on. But what 320 00:12:07.160 --> 00:12:09.520 we're seeing is there's a commonality among a 321 00:12:09.520 --> 00:12:11.240 lot of the planetary systems that we find 322 00:12:11.240 --> 00:12:13.200 that look very different to ours. 323 00:12:14.290 --> 00:12:16.090 The thing that gives us a little bit of pause 324 00:12:16.090 --> 00:12:17.930 though, is that we have these observational 325 00:12:17.930 --> 00:12:19.890 biases that make us more likely to find 326 00:12:19.890 --> 00:12:22.330 systems that are different to ours than we 327 00:12:22.330 --> 00:12:24.970 are to find systems like ours. And so you've 328 00:12:24.970 --> 00:12:27.250 always got that question of do we look 329 00:12:27.250 --> 00:12:30.170 unusual because we are unusual, 330 00:12:30.170 --> 00:12:31.890 or do we look unusual because we're not yet 331 00:12:31.890 --> 00:12:33.730 very good at finding places that look like 332 00:12:33.730 --> 00:12:35.550 home? and that's where colleagues of mine, 333 00:12:35.550 --> 00:12:37.660 like professor, Rob Wittenmayer, my colleague 334 00:12:37.660 --> 00:12:40.620 at unisq, have done really interesting 335 00:12:40.620 --> 00:12:43.580 work where what they 336 00:12:43.580 --> 00:12:46.380 do is look at what we found, but work 337 00:12:46.380 --> 00:12:49.260 out what doesn't exist 338 00:12:49.260 --> 00:12:52.100 based on what we haven't found yet. So they 339 00:12:52.100 --> 00:12:54.340 can start getting an estimate of how common 340 00:12:54.420 --> 00:12:57.060 our, ah, planetary systems like ours based on 341 00:12:57.060 --> 00:12:59.740 the fact we haven't found them yet. And it's 342 00:12:59.740 --> 00:13:02.260 a really kind of weird type of science where 343 00:13:02.820 --> 00:13:05.500 the absence of finding thing places limits on 344 00:13:05.500 --> 00:13:08.340 how common that thing is. So if you said 345 00:13:08.340 --> 00:13:10.580 that every star had a planet exactly like the 346 00:13:10.580 --> 00:13:12.740 Earth, on an orbit that's one year long that 347 00:13:12.740 --> 00:13:14.700 is exactly the same size as us and all the 348 00:13:14.700 --> 00:13:16.900 rest of it, then we can work out 349 00:13:16.900 --> 00:13:18.740 statistically, based on how good our 350 00:13:18.740 --> 00:13:21.260 telescopes are and our techniques are, how 351 00:13:21.260 --> 00:13:23.019 many of those planets we would have found. 352 00:13:23.019 --> 00:13:24.660 And we wouldn't have found anywhere near all 353 00:13:24.660 --> 00:13:26.900 of them because it's really hard to do. But 354 00:13:26.900 --> 00:13:28.830 we'd have found X amount. And the fact that 355 00:13:28.830 --> 00:13:30.830 we've only found a very small number smaller 356 00:13:30.830 --> 00:13:33.590 than that places an upper limit on how common 357 00:13:33.590 --> 00:13:36.200 things can be. So you get this perverse 358 00:13:36.360 --> 00:13:39.160 science where you get the observations 359 00:13:39.160 --> 00:13:40.800 that tell us what we found and what we've 360 00:13:40.800 --> 00:13:43.600 seen, but you can also put inferences on 361 00:13:43.600 --> 00:13:45.620 what isn't there and what is there based on 362 00:13:45.620 --> 00:13:47.900 what we haven't found yet, which allows you 363 00:13:47.900 --> 00:13:49.820 to put limits on how common things are that 364 00:13:49.820 --> 00:13:52.820 you couldn't really find very easily. Which, 365 00:13:52.820 --> 00:13:54.260 if that makes your head hurt. it makes my 366 00:13:54.260 --> 00:13:56.260 head hurt a little bit as well. But it's a 367 00:13:56.260 --> 00:13:59.180 really kind of clever use of the data we get 368 00:13:59.750 --> 00:14:01.750 to extrapolate further and draw more 369 00:14:01.750 --> 00:14:04.430 conclusions. And the net result of that is 370 00:14:04.430 --> 00:14:07.390 that the solar system is not hugely rare, but 371 00:14:07.390 --> 00:14:10.070 it's not common either. It's usual. 372 00:14:10.390 --> 00:14:11.690 And, that's really cool. And that probably 373 00:14:11.690 --> 00:14:13.370 extends to everything. Like I say, we're all 374 00:14:13.370 --> 00:14:16.370 individuals. The Earth, even though it's 375 00:14:16.370 --> 00:14:18.010 peeing it down outside at the minute, the 376 00:14:18.010 --> 00:14:20.570 Earth's actually a very dry planet. If you 377 00:14:20.570 --> 00:14:22.130 took all the water off the Earth and made a 378 00:14:22.130 --> 00:14:23.420 little blob of it next to the Earth, that 379 00:14:23.420 --> 00:14:25.860 blob would be fairly tiny. And everybody 380 00:14:25.860 --> 00:14:27.620 views the Earth as being very wet, but I view 381 00:14:27.620 --> 00:14:30.580 it as being very dry because water is such a 382 00:14:30.580 --> 00:14:33.500 common compound in the universe. It's made of 383 00:14:33.500 --> 00:14:36.020 the first and third most common atom. You put 384 00:14:36.020 --> 00:14:37.900 them together. Yet water waters everywhere. 385 00:14:37.900 --> 00:14:40.580 So for the Earth to be as dry as it is is 386 00:14:40.580 --> 00:14:42.660 telling you a lot about the uniqueness of the 387 00:14:42.660 --> 00:14:44.780 solar system. And maybe that's partially 388 00:14:44.780 --> 00:14:46.710 because of Jupiter. Not, necessarily 389 00:14:46.710 --> 00:14:48.550 shielding us from impacts, but preventing 390 00:14:48.550 --> 00:14:51.430 that icy material spiraling in, preventing 391 00:14:51.430 --> 00:14:54.390 us from becoming an ocean world. It's also 392 00:14:54.390 --> 00:14:56.150 partly down to the moon forming impact. The 393 00:14:56.150 --> 00:14:57.750 moon forming impact would have stripped a lot 394 00:14:57.750 --> 00:14:59.990 of the primordial Earth's water away because 395 00:14:59.990 --> 00:15:02.110 it walked as light and sits near the surface. 396 00:15:02.830 --> 00:15:05.430 So a lot about our Earth and a lot about the 397 00:15:05.430 --> 00:15:08.190 solar system is down to the random nature of 398 00:15:08.190 --> 00:15:11.110 the events around us. When we formed the moon 399 00:15:11.110 --> 00:15:13.470 forming impact, a nearby star going 400 00:15:13.470 --> 00:15:15.750 supernova and lacing our solar system with 401 00:15:15.750 --> 00:15:17.840 radioactive aluminium. Things like this. 402 00:15:17.840 --> 00:15:19.400 There's all these oddities that made our 403 00:15:19.400 --> 00:15:22.200 solar system unique, but if those 404 00:15:22.200 --> 00:15:23.720 hadn't happened, other things would have 405 00:15:23.720 --> 00:15:25.040 happened and we'd have still ended up with 406 00:15:25.040 --> 00:15:26.840 something unique because of other random 407 00:15:26.840 --> 00:15:27.600 things happening. 408 00:15:28.320 --> 00:15:30.440 It's all fascinating and I just love this 409 00:15:30.440 --> 00:15:30.800 stuff. 410 00:15:31.120 --> 00:15:33.440 Andrew Dunkley: Yeah. And it adds more and more weight to the 411 00:15:33.440 --> 00:15:35.840 theory that we are just a freak accident. 412 00:15:36.000 --> 00:15:36.560 Jonti Horner: Yes. 413 00:15:37.040 --> 00:15:39.040 Andrew Dunkley: And probably a one off in the universe. 414 00:15:39.760 --> 00:15:41.920 That's one argument. So, yeah, 415 00:15:42.560 --> 00:15:45.410 who knows if, if we find a 416 00:15:45.410 --> 00:15:47.330 solar system just like ours, with a planet 417 00:15:47.330 --> 00:15:50.120 just like ours, orbiting a 418 00:15:50.440 --> 00:15:53.080 star just like ours. That would be 419 00:15:53.720 --> 00:15:56.680 the, you know, one of the greatest 420 00:15:56.680 --> 00:15:58.560 discoveries in astronomical history, I 421 00:15:58.560 --> 00:16:01.440 imagine. But no, we do that. 422 00:16:01.440 --> 00:16:02.960 Jonti Horner: We would have to get in touch with the planet 423 00:16:02.960 --> 00:16:04.720 builders at Magrathea and demand that money 424 00:16:04.720 --> 00:16:06.120 back. Because we thought we had a limited 425 00:16:06.120 --> 00:16:06.600 edition. 426 00:16:06.760 --> 00:16:09.350 Andrew Dunkley: Yes, yes. weren't they the white mice? Was 427 00:16:09.350 --> 00:16:10.270 that the white mice? 428 00:16:10.350 --> 00:16:11.600 Jonti Horner: Yes, it was. 429 00:16:11.600 --> 00:16:13.320 Andrew Dunkley: Yeah. All right, if you want to read all 430 00:16:13.320 --> 00:16:15.880 about it, you can find, the paper, 431 00:16:16.540 --> 00:16:19.240 which was published in the journal Science 432 00:16:19.400 --> 00:16:20.040 Advances. 433 00:16:23.000 --> 00:16:25.960 Jonti Horner: Roger, your labs are here. Also space nuts. 434 00:16:26.180 --> 00:16:28.350 Andrew Dunkley: now, Jonti, let's move on to our next story. 435 00:16:28.430 --> 00:16:31.260 And this one is about a planetismal, 436 00:16:32.190 --> 00:16:35.110 that appears doomed. According to the, paper 437 00:16:35.110 --> 00:16:37.190 I'm reading, it's a white dwarf that's 438 00:16:37.190 --> 00:16:39.790 chowing down very, very hungry, hungry 439 00:16:39.790 --> 00:16:40.990 individual is this one. 440 00:16:41.790 --> 00:16:44.270 Jonti Horner: It is. So just to remind the audience, a 441 00:16:44.270 --> 00:16:47.030 white dwarf is the kind of little husk 442 00:16:47.030 --> 00:16:48.990 that's left after a cell like our sun comes 443 00:16:48.990 --> 00:16:51.430 to the end of its life, burns all its 444 00:16:51.430 --> 00:16:53.870 hydrogen, becomes a red giant, and then 445 00:16:53.870 --> 00:16:55.750 eventually blows off its outer layers. And it 446 00:16:55.750 --> 00:16:58.110 leaves a big chunk of the star's mass 447 00:16:58.510 --> 00:17:00.350 compressed into an object about the size of 448 00:17:00.350 --> 00:17:03.270 the Earth. That whole process will 449 00:17:03.270 --> 00:17:05.870 have a fairly hefty impact on the 450 00:17:05.870 --> 00:17:07.870 planetary system that star's got around it. 451 00:17:08.230 --> 00:17:09.710 And of course, as we just discussed, we now 452 00:17:09.710 --> 00:17:11.670 know that pretty much every star has planets. 453 00:17:12.150 --> 00:17:14.310 The expectation is that when the sun reaches 454 00:17:14.310 --> 00:17:16.350 this stage, unfortunately it's in about 7 455 00:17:16.350 --> 00:17:18.060 billion years, so nothing to worry about. 456 00:17:18.060 --> 00:17:20.700 Immediately it will swell up and it will 457 00:17:20.860 --> 00:17:23.020 chow down on Mercury and chow down on Venus. 458 00:17:23.020 --> 00:17:25.820 They'll just be swallowed up and gone. Yeah, 459 00:17:25.820 --> 00:17:27.700 There is some debate over whether the Earth 460 00:17:27.700 --> 00:17:30.300 will be swallowed up or will survive. Just 461 00:17:31.100 --> 00:17:33.230 all the models of star, evolution suggest 462 00:17:33.230 --> 00:17:35.190 that the sun will swell up to be about the 463 00:17:35.190 --> 00:17:37.510 radius of the Earth's orbit. But whether the 464 00:17:37.510 --> 00:17:39.390 Earth is there to nominal or not is still 465 00:17:39.390 --> 00:17:41.870 open for debate. It may be that the loss of 466 00:17:41.870 --> 00:17:44.590 mass from the sun in the time before may just 467 00:17:44.590 --> 00:17:46.670 mean that the Earth nudges far enough away to 468 00:17:46.670 --> 00:17:48.510 survive as a burnt husk rather than be 469 00:17:48.510 --> 00:17:51.430 devoured. It still would be ideal 470 00:17:51.430 --> 00:17:53.270 to be around when that wouldn't be pleasant. 471 00:17:53.270 --> 00:17:54.630 I mean, that said, the Earth is going to 472 00:17:54.630 --> 00:17:56.870 become uninhabitable a lot sooner than that 473 00:17:56.870 --> 00:17:58.750 because the Sun's getting brighter and the 474 00:17:58.750 --> 00:18:01.550 Earth's oceans will boil and it'll all go 475 00:18:01.550 --> 00:18:04.460 downhill. But after all that process 476 00:18:04.460 --> 00:18:06.700 happens when the sun sheds its outer layers, 477 00:18:07.020 --> 00:18:09.380 that'll have a pretty cataclysmic event on 478 00:18:09.380 --> 00:18:12.060 the planets and the debris that are left. So 479 00:18:12.060 --> 00:18:14.020 suddenly the sun goes on the ultimate kind of 480 00:18:14.020 --> 00:18:16.860 weight loss kick loses mass. And that 481 00:18:16.860 --> 00:18:18.860 will mean that all of the objects going 482 00:18:18.860 --> 00:18:21.300 around the sun will be held less strongly. 483 00:18:21.300 --> 00:18:23.020 And so therefore their orbits will move 484 00:18:23.020 --> 00:18:25.700 outwards because the gravity pulling them in 485 00:18:25.700 --> 00:18:28.580 gets weaker. Now, if you suddenly Press the 486 00:18:28.580 --> 00:18:30.960 button and vanished half of the mass of the 487 00:18:30.960 --> 00:18:33.560 Sun. What had happened is that the speed that 488 00:18:33.560 --> 00:18:35.720 any of the objects are going in their orbit 489 00:18:35.880 --> 00:18:37.680 will be too quick for that orbit to be 490 00:18:37.680 --> 00:18:40.520 circular. So at that instant, at that 491 00:18:40.520 --> 00:18:43.040 point, they'd now be at their new perihelion, 492 00:18:43.040 --> 00:18:44.560 they'd be at their closest point to the sun, 493 00:18:44.560 --> 00:18:45.960 and they'd all move out onto much more 494 00:18:45.960 --> 00:18:48.520 elongated orbits with a longer orbital 495 00:18:48.520 --> 00:18:51.200 period, but orbits that would then cross one 496 00:18:51.200 --> 00:18:53.640 another. So if you imagine you lose half of 497 00:18:53.640 --> 00:18:56.320 the Sun's mass, Jupiter moves onto an orbit 498 00:18:56.320 --> 00:18:58.480 where its perihelion is 5 au from the sun, 499 00:18:58.480 --> 00:19:00.840 but its aphelion could be 15 au from the Sun. 500 00:19:01.400 --> 00:19:03.760 Saturn at the same time would have perihelion 501 00:19:03.760 --> 00:19:06.120 at 10 au and aphelion at say 20 au. And I'm 502 00:19:06.120 --> 00:19:08.440 making the numbers up a bit here. So suddenly 503 00:19:08.440 --> 00:19:11.199 Jupiter and Saturn are on orbits that 504 00:19:11.199 --> 00:19:14.120 cross one another. Their orbits 505 00:19:14.120 --> 00:19:16.520 will probably still have the same ratio of 506 00:19:16.520 --> 00:19:19.400 orbital periods, so 12 years to 29 years. But 507 00:19:19.400 --> 00:19:21.290 they'd scale up to be something like, I don't 508 00:19:21.290 --> 00:19:23.650 know, 30 to 70 or something like that, 509 00:19:23.970 --> 00:19:25.570 because they've both moved out by the same 510 00:19:25.570 --> 00:19:27.650 amount. But suddenly you've got these planets 511 00:19:27.650 --> 00:19:29.450 that are on orbits that cross each other and 512 00:19:29.450 --> 00:19:32.130 therefore can really strongly interact. They 513 00:19:32.130 --> 00:19:33.890 can stir everything else up because all of 514 00:19:33.890 --> 00:19:35.570 the objects in the asteroid belt, all of the 515 00:19:35.570 --> 00:19:37.330 objects beyond Neptune, this happens to 516 00:19:37.330 --> 00:19:39.770 everything. Now the mass loss is a bit more 517 00:19:39.770 --> 00:19:42.330 gradual than that in actuality. So what 518 00:19:42.330 --> 00:19:44.370 happens is you get the orbit spiraling out, 519 00:19:44.370 --> 00:19:46.170 but getting perturbed, being made more 520 00:19:46.170 --> 00:19:48.640 eccentric. You've also got these objects 521 00:19:48.640 --> 00:19:51.240 moving through the headwind of possibly half 522 00:19:51.240 --> 00:19:53.200 a solar mass of material being blown 523 00:19:53.200 --> 00:19:55.560 outwards. That provides friction and so 524 00:19:55.560 --> 00:19:57.720 causes them possibly to spiral inwards a bit. 525 00:19:58.520 --> 00:20:00.760 Causes Jupiter potentially to gather mass as 526 00:20:00.760 --> 00:20:03.400 it numbs on all that gas that's going out. At 527 00:20:03.400 --> 00:20:04.960 the same time, its atmosphere is probably 528 00:20:04.960 --> 00:20:07.360 being blasted away by all this wind blowing 529 00:20:07.360 --> 00:20:10.280 past. All of this complexity means 530 00:20:10.280 --> 00:20:12.200 that you couldn't predict with absolute 531 00:20:12.200 --> 00:20:14.080 certainty what the solar system would look 532 00:20:14.080 --> 00:20:16.920 like at the end of this, but certainly 533 00:20:16.920 --> 00:20:19.320 there'd be a period of chaos. A lot of stuff 534 00:20:19.320 --> 00:20:21.800 would survive, but it would survive on orbits 535 00:20:21.800 --> 00:20:24.520 that are now much more unstable. So you get a 536 00:20:24.520 --> 00:20:26.570 lot of material flung inwards and, some of 537 00:20:26.570 --> 00:20:29.170 that will be flung inwards far enough for it 538 00:20:29.170 --> 00:20:31.370 to impact on the Earth sized object in the 539 00:20:31.370 --> 00:20:33.700 middle and, for the white dwarf to get a 540 00:20:33.700 --> 00:20:36.300 snack. Now all that's expected to happen 541 00:20:36.300 --> 00:20:38.860 really early on. And over time everything 542 00:20:38.860 --> 00:20:41.530 stabilizes out, things get flung around and 543 00:20:41.530 --> 00:20:44.250 clean up happens a bit like the 544 00:20:44.250 --> 00:20:45.730 solar system. You know, we were talking early 545 00:20:45.730 --> 00:20:47.170 on about the early stages of planet 546 00:20:47.170 --> 00:20:49.090 formation. Everything gets flung around and 547 00:20:49.090 --> 00:20:51.210 by the time you get to now, four and a half 548 00:20:51.210 --> 00:20:52.770 billion years down the road, it's fairly 549 00:20:52.770 --> 00:20:55.210 quiet. There's a bit going on, but most of 550 00:20:55.210 --> 00:20:57.730 the drama's finished. So the 551 00:20:57.730 --> 00:20:59.730 expectation is you'd see white dwarfs that 552 00:20:59.730 --> 00:21:02.450 are very young occasionally eating things 553 00:21:02.450 --> 00:21:04.650 because things get flung in and they get a 554 00:21:04.650 --> 00:21:06.780 bit of a snack. And the material from that 555 00:21:06.780 --> 00:21:08.820 snack will be spattered over the surface of 556 00:21:08.820 --> 00:21:10.980 the white dwarf and be visible in its 557 00:21:10.980 --> 00:21:13.620 spectrum as anomalous added 558 00:21:14.100 --> 00:21:16.420 solid material, heavy elements. 559 00:21:17.140 --> 00:21:19.300 But that signal would only last a short time 560 00:21:19.300 --> 00:21:21.220 because the outer layer of the white dwarf is 561 00:21:21.220 --> 00:21:24.220 kind of a hydrogen soup and heavier elements 562 00:21:24.220 --> 00:21:27.140 would sink down. So any given time you'd eat 563 00:21:27.140 --> 00:21:29.660 something. The evidence for that meal would 564 00:21:29.660 --> 00:21:31.740 only remain for a few tens of thousands of 565 00:21:31.740 --> 00:21:34.650 years, SOPs before it goes away. Okay, so 566 00:21:34.650 --> 00:21:36.530 the fact is we've seen some white dwarfs 567 00:21:36.530 --> 00:21:38.810 which have these anomalous heavy element 568 00:21:38.810 --> 00:21:41.010 readings in their atmospheres. We can tell 569 00:21:41.010 --> 00:21:42.690 they're eating stuff, but typically they're 570 00:21:42.690 --> 00:21:45.450 young. So you'd expect that. 571 00:21:45.930 --> 00:21:48.010 The quirky thing here is that this white 572 00:21:48.010 --> 00:21:49.850 dwarf, which goes by the name of 573 00:21:49.850 --> 00:21:52.820 lspm, which I think is a survey name, 574 00:21:52.820 --> 00:21:54.010 m followed by 575 00:21:54.010 --> 00:21:57.770 J020733331. 576 00:21:58.330 --> 00:22:00.210 So that's a coordinate on the sky. So that's 577 00:22:00.210 --> 00:22:01.690 telling you where in the sky this is. It's 578 00:22:01.690 --> 00:22:04.390 catalog number. Yeah, this thing is an old 579 00:22:04.390 --> 00:22:06.310 white dwarf. It's thought to be about 3 580 00:22:06.310 --> 00:22:08.350 billion years old. So in other words, the 581 00:22:08.350 --> 00:22:11.230 star that formed it died 3 582 00:22:11.230 --> 00:22:13.510 billion years ago and it's been sitting there 583 00:22:13.510 --> 00:22:16.390 minding its own business. That's old enough 584 00:22:16.390 --> 00:22:18.070 that you'd expect everything to have calmed 585 00:22:18.070 --> 00:22:20.910 down around it. But what the new 586 00:22:20.910 --> 00:22:23.870 observations have shown is evidence of 587 00:22:23.870 --> 00:22:25.870 13 different heavy elements, 588 00:22:26.670 --> 00:22:28.750 including carbon, chromium, 589 00:22:29.980 --> 00:22:32.220 strontium, titanium, a lot of these different 590 00:22:32.220 --> 00:22:35.100 elements, roughly in the kind of abundance as 591 00:22:35.100 --> 00:22:37.630 you'd see on the Earth, added, to this white 592 00:22:37.630 --> 00:22:40.230 dwarf's atmosphere. So it's 593 00:22:40.230 --> 00:22:42.350 obviously just had a meal and we know it's a 594 00:22:42.350 --> 00:22:44.470 case of just had a meal rather than it's been 595 00:22:44.470 --> 00:22:47.190 a leftover from a long time ago, because this 596 00:22:47.190 --> 00:22:49.150 stuff will sink and disappear over the next 597 00:22:49.150 --> 00:22:52.110 few tens of thousands of years. So what 598 00:22:52.110 --> 00:22:54.190 that means is that this white dwarf 599 00:22:55.020 --> 00:22:57.380 has just had a snack. Now it might have had 600 00:22:57.380 --> 00:23:00.220 that snack 30,000 years ago, or it 601 00:23:00.220 --> 00:23:03.020 may still be in the process of eating as 602 00:23:03.020 --> 00:23:05.820 we speak. Now what the team have been able to 603 00:23:05.820 --> 00:23:08.340 do is look at the amount of material you'd 604 00:23:08.340 --> 00:23:10.140 need to give the strength of signal you've 605 00:23:10.140 --> 00:23:12.080 got in the spectrum of the star. And, what 606 00:23:12.080 --> 00:23:14.320 they've calculated is that to get this amount 607 00:23:14.320 --> 00:23:17.080 of material you'd need to eat an asteroid 608 00:23:17.800 --> 00:23:19.960 about 200 kilometers in diameter. 609 00:23:20.760 --> 00:23:22.520 So that's comparable to some of the larger 610 00:23:22.520 --> 00:23:24.200 asteroids in the asteroid belt, but not the 611 00:23:24.200 --> 00:23:26.920 largest by any means. It's within the bounds 612 00:23:26.920 --> 00:23:28.680 of possibility of what we see here at home. 613 00:23:29.080 --> 00:23:31.160 But the real question is why is it eating it 614 00:23:31.160 --> 00:23:33.520 now? Why is this happening now when you'd 615 00:23:33.520 --> 00:23:35.200 expect the system to have had plenty of time 616 00:23:35.200 --> 00:23:37.560 to calm down? What 617 00:23:37.960 --> 00:23:40.760 it suggests to me, and it suggests in the 618 00:23:40.760 --> 00:23:42.960 paper, it suggests in the articles about this 619 00:23:42.960 --> 00:23:45.240 as well, is that the only way you can get 620 00:23:45.240 --> 00:23:48.070 something eating this late, after 3 billion 621 00:23:48.070 --> 00:23:50.830 years have passed, is if you've still got a 622 00:23:50.830 --> 00:23:53.310 number of planet mass objects in the system 623 00:23:53.310 --> 00:23:56.230 serving things up, which is what we've got 624 00:23:56.230 --> 00:23:57.910 in the solar system. If we look at the inner 625 00:23:57.910 --> 00:24:00.270 solar system, fragments of comets and 626 00:24:00.270 --> 00:24:02.070 asteroids are falling onto the sun all the 627 00:24:02.070 --> 00:24:04.350 time. We've got near Earth asteroids, short 628 00:24:04.350 --> 00:24:06.390 period comets and long period comets whizzing 629 00:24:06.390 --> 00:24:08.760 around. And, they're being bounced around by 630 00:24:08.760 --> 00:24:10.480 the planets. Jupiter's throwing a lot of 631 00:24:10.480 --> 00:24:12.920 stuff away. Their orbits are constantly 632 00:24:12.920 --> 00:24:15.800 getting tweaked. And so therefore the sun 633 00:24:15.800 --> 00:24:18.640 is still getting this rain of solid material 634 00:24:18.640 --> 00:24:20.880 falling on it as a result of the planets 635 00:24:20.880 --> 00:24:23.560 stirring things up. Even though the solar 636 00:24:23.560 --> 00:24:25.760 system mostly quietened down, the planets are 637 00:24:25.760 --> 00:24:28.320 still injecting material to the inner solar 638 00:24:28.320 --> 00:24:30.760 system, which is why we're getting meteorites 639 00:24:30.760 --> 00:24:32.400 and it's why the sun occasionally gets to 640 00:24:32.400 --> 00:24:35.120 numb some stuff. The idea here is 641 00:24:35.120 --> 00:24:37.400 that this star reached the end of its life. 642 00:24:37.400 --> 00:24:40.260 Puff dots with its outer layers. You have 643 00:24:40.260 --> 00:24:42.260 this really chaotic period where everything 644 00:24:42.260 --> 00:24:44.820 had got stirred up, then it settled down. But 645 00:24:44.820 --> 00:24:46.660 because you still got planet mass objects 646 00:24:46.660 --> 00:24:49.020 there, they're still bouncing around what 647 00:24:49.020 --> 00:24:51.620 debris is left. And we're just catching this 648 00:24:51.620 --> 00:24:54.460 white dwarf just at the right time, when 649 00:24:54.460 --> 00:24:56.740 another asteroid has been flung inwards close 650 00:24:56.740 --> 00:24:59.100 enough to be torn apart by the star's gravity 651 00:24:59.260 --> 00:25:01.900 and to give it a snack. So in other words, 652 00:25:02.220 --> 00:25:04.460 seeing this snack happening this late in the 653 00:25:04.460 --> 00:25:07.060 life of this white dwarf is fairly strong 654 00:25:07.060 --> 00:25:09.500 evidence that planets survived the death of 655 00:25:09.500 --> 00:25:12.140 its star, have lived there for 3 billion 656 00:25:12.140 --> 00:25:14.460 years, which a is really cool in of itself. 657 00:25:14.460 --> 00:25:17.380 But it also means that here is a star that we 658 00:25:17.380 --> 00:25:19.860 should look at when the Gaia data release 659 00:25:19.940 --> 00:25:22.500 comes next year. Gaia Dr. AH4, 660 00:25:22.980 --> 00:25:24.780 which will have been measuring this star's 661 00:25:24.780 --> 00:25:26.460 position on the sky. And if there Are planets 662 00:25:26.460 --> 00:25:28.220 there, we'll be able to detect the wobble and 663 00:25:28.220 --> 00:25:31.100 confirm them. So it's also holding up a flag 664 00:25:31.100 --> 00:25:33.760 to exoplanet people saying, 665 00:25:33.920 --> 00:25:36.520 hey, folks, here's a target for you to look 666 00:25:36.520 --> 00:25:38.320 at when the data release comes out where you 667 00:25:38.320 --> 00:25:39.840 might be able to find some planets, because 668 00:25:39.840 --> 00:25:42.240 we think there's a smoking gun here that the 669 00:25:42.240 --> 00:25:44.600 planets are feeding the white dwarf, giving 670 00:25:44.600 --> 00:25:46.160 it little snacks every now and again. 671 00:25:47.120 --> 00:25:49.040 Andrew Dunkley: Okay, wow. All right. 672 00:25:49.040 --> 00:25:51.950 so are there many white dwarf 673 00:25:52.030 --> 00:25:54.830 stars out there? What, do they, sort of, 674 00:25:55.870 --> 00:25:58.560 percentage wise, inhabit the star field? 675 00:25:58.720 --> 00:26:01.480 Jonti Horner: There would be a fair few of them. So the 676 00:26:01.480 --> 00:26:03.600 more massive a star is, the shorter its life 677 00:26:03.600 --> 00:26:05.850 is. And, that's a really rapid function. 678 00:26:06.330 --> 00:26:08.860 Where that works is, if your star's more 679 00:26:08.860 --> 00:26:11.420 massive, its gravitational pull is stronger, 680 00:26:11.980 --> 00:26:14.940 so its ability to pull material into 681 00:26:14.940 --> 00:26:17.900 the middle of the star is higher, which means 682 00:26:17.900 --> 00:26:19.780 that that star's got to give off a lot more 683 00:26:19.780 --> 00:26:21.900 energy to balance that gravitational pull. 684 00:26:21.900 --> 00:26:24.140 And so stars in the main sequence part of 685 00:26:24.140 --> 00:26:26.690 their life are in equilibrium. The radiation 686 00:26:26.690 --> 00:26:28.330 coming out from the nuclear fusion in the 687 00:26:28.330 --> 00:26:31.250 middle balances gravity pulling in. The 688 00:26:31.250 --> 00:26:33.730 more massive you are, the hotter and denser 689 00:26:33.730 --> 00:26:35.490 you get in the middle, so the more energy you 690 00:26:35.490 --> 00:26:38.250 give off. And the result of that is that it 691 00:26:38.650 --> 00:26:40.809 roughly, it varies a little bit by star's 692 00:26:40.809 --> 00:26:42.850 mass, but roughly the brightness of a star, 693 00:26:42.850 --> 00:26:45.570 the luminosity of a star is proportional to 694 00:26:45.570 --> 00:26:47.050 the mass of the star to the power 695 00:26:47.050 --> 00:26:49.890 4.3.54. Which means if you 696 00:26:49.890 --> 00:26:52.480 double the mass of a star, it'll get between 697 00:26:52.480 --> 00:26:54.560 10 and 16 times brighter. 698 00:26:55.440 --> 00:26:58.240 So twice the mass, Call it a factor of 10 699 00:26:58.240 --> 00:26:59.960 just to keep it easy. If it's 10 times 700 00:26:59.960 --> 00:27:02.600 brighter, that means it's burning its fuel 10 701 00:27:02.600 --> 00:27:04.880 times quicker to produce 10 times as much 702 00:27:04.880 --> 00:27:07.120 energy. But it's only twice the mass, so it's 703 00:27:07.120 --> 00:27:09.920 only got twice as much fuel, so its 704 00:27:09.920 --> 00:27:11.920 life will be a factor of five times shorter. 705 00:27:12.080 --> 00:27:13.800 And the more massive you get, the shorter the 706 00:27:13.800 --> 00:27:16.640 life gets. Now, stars of different masses 707 00:27:16.720 --> 00:27:19.330 have different. A star like Proxima 708 00:27:19.330 --> 00:27:21.770 Centauri will never swell up to become a red 709 00:27:21.770 --> 00:27:23.490 giant. It'll just be a dull, glowing ember 710 00:27:23.490 --> 00:27:26.090 and eventually go out. But even the 711 00:27:26.090 --> 00:27:28.570 oldest stars like Proxima Centauri are still 712 00:27:28.730 --> 00:27:30.370 really in their youth because they're burning 713 00:27:30.370 --> 00:27:33.170 their fuel so slowly. Stars that are more 714 00:27:33.170 --> 00:27:35.050 massive eventually get stars like the sun, 715 00:27:35.050 --> 00:27:37.520 which are what form like dwarfs. And, they 716 00:27:37.680 --> 00:27:39.600 eventually swell up to become a red giant, 717 00:27:39.600 --> 00:27:41.680 puff off their outer layers. And for a star 718 00:27:42.000 --> 00:27:44.930 of the Sun's mass, that process from 719 00:27:44.930 --> 00:27:46.770 forming to the end of its life is thought to 720 00:27:46.770 --> 00:27:49.010 be about 12 billion years. It used to be 10 721 00:27:49.010 --> 00:27:51.130 billion models seem to have refined. So 722 00:27:51.130 --> 00:27:52.730 people nowadays seem to say it's about 12 723 00:27:52.730 --> 00:27:55.690 billion years. So a star of 724 00:27:55.690 --> 00:27:58.180 the mass of the sun that formed when our, 725 00:27:58.180 --> 00:28:00.740 Milky Way was very young will have lived and 726 00:28:00.740 --> 00:28:02.900 died and become a white dwarf more than a 727 00:28:02.900 --> 00:28:05.860 billion years ago. But stars more massive 728 00:28:05.860 --> 00:28:08.180 than the sun can form white dwarfs as well, 729 00:28:08.180 --> 00:28:10.750 up to maybe two or even three times the mass 730 00:28:10.750 --> 00:28:12.590 of the sun, depending how effective it is at 731 00:28:12.590 --> 00:28:14.870 shedding mass at the end. Yeah, the maximum 732 00:28:14.870 --> 00:28:17.070 mass for white dwarf, you can get about 1.4 733 00:28:17.070 --> 00:28:19.390 times the mass of the Sun. If stars lose half 734 00:28:19.390 --> 00:28:20.750 their mass, that gives you something about 735 00:28:20.750 --> 00:28:22.710 three times the mass of the sun before you 736 00:28:22.710 --> 00:28:25.430 start it. Three times the mass of the sun. 737 00:28:26.150 --> 00:28:28.230 Three to the power four is three times three 738 00:28:28.230 --> 00:28:30.430 times three times three. That's 81 if my 739 00:28:30.430 --> 00:28:33.030 mental arithmetic is correct. So three times 740 00:28:33.030 --> 00:28:35.270 the mass of the sun burns its fuel 81 times 741 00:28:35.270 --> 00:28:38.050 as quickly, which means it would live a 27th 742 00:28:38.050 --> 00:28:40.930 as long. Which means instead of 12 billion 743 00:28:40.930 --> 00:28:43.400 years, you get down to, 1.2 billion years, 744 00:28:43.400 --> 00:28:45.360 you get down to or like, 600 million years, 745 00:28:45.440 --> 00:28:48.200 500 million years. So there will have been a 746 00:28:48.200 --> 00:28:50.520 lot of stars that were more m massive than 747 00:28:50.520 --> 00:28:52.560 the sun that have lived and died and created 748 00:28:52.560 --> 00:28:54.960 white dwarfs. And so there's going to be a 749 00:28:54.960 --> 00:28:57.880 lot of white dwarfs out there. I saw 750 00:28:57.880 --> 00:29:00.120 someone talking a while back about how old 751 00:29:00.120 --> 00:29:02.760 the oldest white dwarf will be in how dim it 752 00:29:02.760 --> 00:29:04.680 will be, because white dwarfs just cool and 753 00:29:04.680 --> 00:29:07.240 gradually go from being blue to white to 754 00:29:07.240 --> 00:29:09.360 yellow to red. You know, gradually dim down. 755 00:29:09.680 --> 00:29:11.910 Yeah. but what that all means is that there 756 00:29:11.910 --> 00:29:14.350 are probably a really large population of 757 00:29:14.350 --> 00:29:16.190 white dwarfs out there. We know quite a large 758 00:29:16.190 --> 00:29:19.030 number, but we won't know anywhere near 759 00:29:19.030 --> 00:29:21.230 as many of them as we do stars that are 760 00:29:21.230 --> 00:29:22.630 actually the mass of the sun, that are in the 761 00:29:22.630 --> 00:29:24.990 prime of their life because they're much 762 00:29:24.990 --> 00:29:27.110 fainter and harder to spot because they've 763 00:29:27.110 --> 00:29:28.670 got a much smaller surface area. So even 764 00:29:28.670 --> 00:29:30.130 though they're hot, they're tiny and, 765 00:29:30.080 --> 00:29:31.940 therefore they're faint. and the best example 766 00:29:31.940 --> 00:29:33.860 of that, of course, is a white dwarf that is 767 00:29:33.860 --> 00:29:36.220 a companion to Sirius. Sirius is the 768 00:29:36.220 --> 00:29:38.020 brightest star in the night sky. It's more 769 00:29:38.020 --> 00:29:40.860 massive than the Sun. It's also nearby. Its 770 00:29:41.100 --> 00:29:44.060 white dwarf companion is something 771 00:29:44.060 --> 00:29:46.940 like a factor of a million times fainter than 772 00:29:46.940 --> 00:29:49.500 Sirius is. So even though the white dwarf is 773 00:29:49.500 --> 00:29:51.660 comparable in Master Sirius A, 774 00:29:52.300 --> 00:29:55.060 it is like a million times dimmer because 775 00:29:55.060 --> 00:29:57.220 it's so tiny. And that's why they're Hard to 776 00:29:57.220 --> 00:29:57.500 find. 777 00:29:58.270 --> 00:30:00.070 Andrew Dunkley: Yeah, even though there's probably a hell of 778 00:30:00.070 --> 00:30:02.980 a lot of them out there. Okay, if you would 779 00:30:02.980 --> 00:30:05.180 like to read more about this particular white 780 00:30:05.180 --> 00:30:08.050 dwarf star that is, you know, got a case of 781 00:30:08.050 --> 00:30:10.610 the munchies, probably spent too much time 782 00:30:10.770 --> 00:30:13.360 smoking the juju. you can read all about it 783 00:30:14.240 --> 00:30:17.200 in the Astronomical Journal. This is Space 784 00:30:17.200 --> 00:30:20.080 Nuts with Andrew Dunkley and Jonti Horner. 785 00:30:20.240 --> 00:30:22.680 Jonti Horner: Okay, we checked all four systems and being 786 00:30:22.680 --> 00:30:24.170 with the jerk space nets, 787 00:30:25.140 --> 00:30:26.600 Andrew Dunkley: Don'T know why we went down that road. 788 00:30:26.600 --> 00:30:29.280 Let's go to our next story. And this 789 00:30:29.280 --> 00:30:32.050 one is, this one's close to home. 790 00:30:32.080 --> 00:30:35.030 a, an object that is rapidly developing 791 00:30:35.030 --> 00:30:37.840 a ring system and it's it's in 792 00:30:37.840 --> 00:30:40.080 the outer solar system. 793 00:30:40.480 --> 00:30:43.120 Jonti Horner: It is, this is an object called Chiron, 794 00:30:43.920 --> 00:30:45.920 which was the first of the centaurs to be 795 00:30:45.920 --> 00:30:47.240 discovered. And I always like to talk about 796 00:30:47.240 --> 00:30:48.920 the centaurs because they're what I studied 797 00:30:48.920 --> 00:30:51.660 for my PhD, so, so I was at one 798 00:30:51.660 --> 00:30:54.220 point, 20 odd years ago, one of the world's 799 00:30:54.220 --> 00:30:56.140 experts in how these things move around the 800 00:30:56.140 --> 00:30:57.740 solar system. And then science has moved on 801 00:30:57.740 --> 00:31:00.060 and I haven't, so I probably can no longer 802 00:31:00.060 --> 00:31:02.740 claim that. But Chiron is 803 00:31:02.820 --> 00:31:04.980 an interesting object. It's an icy object, 804 00:31:05.220 --> 00:31:08.220 bit more than 200km across. It was 805 00:31:08.220 --> 00:31:10.900 one of, if not the first object to get both a 806 00:31:10.900 --> 00:31:12.980 classification as an asteroid and as a comet. 807 00:31:13.540 --> 00:31:15.940 So it was initially discovered as a tiny 808 00:31:15.940 --> 00:31:17.460 speck of light moving around. It's discovered 809 00:31:17.460 --> 00:31:19.300 by Cowell I think in 1970, 810 00:31:20.340 --> 00:31:22.380 moving on an orbit that spends nearly all its 811 00:31:22.380 --> 00:31:24.220 time between the orbits of Saturn and Uranus. 812 00:31:24.220 --> 00:31:25.980 At the minute. Long term it's an unstable 813 00:31:25.980 --> 00:31:28.500 orbit. There's about a, ah, one in three 814 00:31:28.500 --> 00:31:29.940 chance that this will eventually end up in 815 00:31:29.940 --> 00:31:31.540 the inner solar system at some point in the 816 00:31:31.540 --> 00:31:33.780 next few million years. And that's part of 817 00:31:33.780 --> 00:31:36.060 the work I did during my PhD was running 818 00:31:36.060 --> 00:31:37.540 simulations of where this thing's going to 819 00:31:37.540 --> 00:31:40.100 go. That in itself is interesting because 820 00:31:40.100 --> 00:31:42.580 it's about a bit more than 200km across. 821 00:31:43.300 --> 00:31:44.900 So if this thing got trapped in the inner 822 00:31:44.900 --> 00:31:46.540 solar system, it will be, be a comet like 823 00:31:46.540 --> 00:31:48.780 nothing we've seen in recorded history. Hale 824 00:31:48.780 --> 00:31:51.660 Bopp, which was ridiculous, had a 50 825 00:31:51.660 --> 00:31:54.660 kilometer nucleus. If this thing's 250 826 00:31:54.660 --> 00:31:56.420 kilometers across, that's five times the 827 00:31:56.420 --> 00:31:59.220 radius, which means it's something like 25 828 00:31:59.220 --> 00:32:01.899 times the surface area, which means it will 829 00:32:01.899 --> 00:32:04.450 be a lot more impressive. So it's obviously 830 00:32:04.450 --> 00:32:07.130 an interesting object. Back in 831 00:32:07.130 --> 00:32:10.010 2011, team of scientists 832 00:32:10.410 --> 00:32:13.200 traveled across the world to gather to 833 00:32:13.200 --> 00:32:15.560 watch Chiron block out the light from a 834 00:32:15.640 --> 00:32:18.000 background star. So as this thing's moving 835 00:32:18.000 --> 00:32:20.560 through space, it just happened to pass in 836 00:32:20.560 --> 00:32:23.080 front of a star, from a subset of locations 837 00:32:23.080 --> 00:32:25.680 across the Earth. Now the distant stars are 838 00:32:25.680 --> 00:32:27.839 effectively so far away, we can consider the 839 00:32:27.839 --> 00:32:30.640 light coming in perfectly parallel. And 840 00:32:30.640 --> 00:32:32.200 so a 200 kilometer 841 00:32:33.000 --> 00:32:35.240 centaur will cast a shadow on the earth 842 00:32:35.240 --> 00:32:37.280 that's 200 kilometers across. And that shadow 843 00:32:37.280 --> 00:32:39.730 will whip across our planet. As the object 844 00:32:39.730 --> 00:32:41.570 and the Earth move around the sun, the shadow 845 00:32:41.570 --> 00:32:43.850 moves, the Earth moves through it. And so you 846 00:32:43.850 --> 00:32:46.850 get a 200 kilometer roughly scale band on the 847 00:32:46.850 --> 00:32:48.970 Earth where that star will disappear, then 848 00:32:48.970 --> 00:32:51.810 reappear. We know how fast everything's 849 00:32:51.810 --> 00:32:53.690 moving. So if you can get in that location, 850 00:32:54.010 --> 00:32:56.210 have a lot of telescopes spread out in a 851 00:32:56.210 --> 00:32:58.730 line, you can observe that 852 00:32:58.730 --> 00:33:01.330 occultation event and, by how long the star 853 00:33:01.330 --> 00:33:03.250 vanishes from different locations, you can 854 00:33:03.250 --> 00:33:05.640 actually figure out the shape and the size of 855 00:33:05.640 --> 00:33:08.320 the centaur because you can essentially map 856 00:33:08.560 --> 00:33:11.320 that shadow. And if you're near the edge, the 857 00:33:11.320 --> 00:33:12.880 star will disappear and reappear really 858 00:33:12.880 --> 00:33:14.520 quickly. If you're near the middle, you'll 859 00:33:14.520 --> 00:33:17.080 get a longer period where it vanishes. So 860 00:33:17.080 --> 00:33:18.720 these kind of, ah, occultation observations 861 00:33:18.800 --> 00:33:21.520 are really valuable to scientists. What 862 00:33:21.520 --> 00:33:23.560 happened in 2011 was they set their 863 00:33:23.560 --> 00:33:25.280 telescopes up and started watching a bit 864 00:33:25.280 --> 00:33:26.760 early to make sure they were looking at the 865 00:33:26.760 --> 00:33:29.320 star. And they noticed the star flickered on 866 00:33:29.320 --> 00:33:31.400 and off a couple of times before it properly 867 00:33:31.400 --> 00:33:33.540 disappeared for the main occultation. Then 868 00:33:33.540 --> 00:33:35.380 after it reappeared, it flickered on and off 869 00:33:35.380 --> 00:33:37.580 again a couple of times. And that's really 870 00:33:37.580 --> 00:33:40.420 weird. Now there was a kind of 871 00:33:40.420 --> 00:33:42.260 precedent for this with observations that 872 00:33:42.260 --> 00:33:44.780 were made in 1977, I believe, 873 00:33:45.100 --> 00:33:47.820 of Uranus, which was being observed from, I 874 00:33:47.820 --> 00:33:49.540 think it was the Kuiper Airborne Observatory 875 00:33:49.540 --> 00:33:52.100 doing one of these occultations. And they'd 876 00:33:52.100 --> 00:33:54.660 observed Uranus for this occultation because 877 00:33:54.660 --> 00:33:57.180 they wanted to understand the atmosphere of 878 00:33:57.180 --> 00:33:59.500 Uranus. And they figured as a stalwart behind 879 00:33:59.500 --> 00:34:02.109 Uranus, you'd see it not just disappear, but 880 00:34:02.109 --> 00:34:03.989 actually fade out as the light passed through 881 00:34:03.989 --> 00:34:06.149 the atmosphere. So you could measure the 882 00:34:06.149 --> 00:34:08.549 atmosphere and with that occultation of 883 00:34:08.549 --> 00:34:11.549 Uranus, occultation by Uranus, sorry, they 884 00:34:11.549 --> 00:34:12.949 got this flickering on and off thing. And 885 00:34:12.949 --> 00:34:14.749 that was the discovery of Uranus, of ring 886 00:34:14.749 --> 00:34:17.749 system. So basically the star vanished behind 887 00:34:17.749 --> 00:34:19.149 the rings, then reappeared, then vanished 888 00:34:19.149 --> 00:34:20.749 again, then reappeared, then went behind the 889 00:34:20.749 --> 00:34:23.629 planet. Right. So with this 890 00:34:23.629 --> 00:34:26.589 2011 event, the same kind of thing applied. 891 00:34:27.179 --> 00:34:29.139 It was the discovery of a ring system around 892 00:34:29.139 --> 00:34:31.259 this icy object. So this is a tiny thing, 893 00:34:31.899 --> 00:34:34.539 smaller than even Mimas, that we talked about 894 00:34:34.539 --> 00:34:36.299 last week with the subsurface ocean, 895 00:34:36.539 --> 00:34:38.419 something so small that its gravity is 896 00:34:38.419 --> 00:34:39.659 probably not strong enough to make it 897 00:34:39.659 --> 00:34:42.360 spherical. It's probably peanut shaped or 898 00:34:42.349 --> 00:34:44.028 rugby ball shaped or something like this. 899 00:34:44.028 --> 00:34:46.508 It's probably not spherical. Around this 900 00:34:46.508 --> 00:34:48.628 object, it seems that there is a system of 901 00:34:48.628 --> 00:34:50.268 rings where there are three or four narrow 902 00:34:50.268 --> 00:34:52.548 rings at various distances. I think the 903 00:34:52.548 --> 00:34:55.419 distances are something like 273, 325, 438 904 00:34:55.419 --> 00:34:58.379 and 1400 kilometers from the 905 00:34:58.379 --> 00:35:01.259 center of Chiron. Got this ring 906 00:35:01.259 --> 00:35:03.819 system and it's been observed again since 907 00:35:03.819 --> 00:35:06.739 they did observations in 2018, 2022 and 908 00:35:06.739 --> 00:35:09.579 2023, where they again figured 909 00:35:09.579 --> 00:35:11.579 out that the shadow of Chiron was going to 910 00:35:11.579 --> 00:35:13.939 scan across the planet, got a load of 911 00:35:13.939 --> 00:35:16.299 telescopes, went on a road trip and observed 912 00:35:16.299 --> 00:35:18.739 it happen to get more information about the 913 00:35:18.739 --> 00:35:21.059 rings. Because having a ring system around an 914 00:35:21.059 --> 00:35:23.139 object that isn't a planet is really cool. 915 00:35:23.649 --> 00:35:23.969 Andrew Dunkley: Yeah. 916 00:35:24.049 --> 00:35:26.489 Jonti Horner: And how did it form? How long has it been 917 00:35:26.489 --> 00:35:28.329 there? What's going on? How common are ring 918 00:35:28.329 --> 00:35:31.249 systems like this? Incidentally, a former PhD 919 00:35:31.249 --> 00:35:33.649 student of mine, Jeremy Wood, did some really 920 00:35:33.649 --> 00:35:36.089 cool dynamical studies that basically showed 921 00:35:36.089 --> 00:35:38.289 that the ring system could be 922 00:35:38.449 --> 00:35:40.809 primordial. It could be as old as the solar 923 00:35:40.809 --> 00:35:43.129 system. From the point of view of Chiron has 924 00:35:43.129 --> 00:35:45.009 never been close enough to one of the planets 925 00:35:45.009 --> 00:35:48.009 to disrupt the rings. So that 926 00:35:48.009 --> 00:35:49.529 doesn't put an edge limit on it, but it was 927 00:35:49.529 --> 00:35:52.169 still quite cool. What the new observations 928 00:35:52.169 --> 00:35:53.749 have shown though, is that, the ring system 929 00:35:53.829 --> 00:35:56.309 now seems to be different to how it was in 930 00:35:56.309 --> 00:35:59.269 2011. In other words, the ring 931 00:35:59.269 --> 00:36:01.949 system is evolving before our very 932 00:36:01.949 --> 00:36:04.069 eyes and it actually seems to be a denser, 933 00:36:04.069 --> 00:36:06.829 stronger ring system now than it was 10 or 15 934 00:36:06.829 --> 00:36:09.109 years ago. So it's possible that we're 935 00:36:09.109 --> 00:36:11.389 actually witnessing this ring system as it is 936 00:36:11.389 --> 00:36:14.069 forming or as it's changing over time. 937 00:36:14.069 --> 00:36:16.869 Now I know Chiron has been quite active, 938 00:36:17.309 --> 00:36:19.469 it's been outgassing because it's been closer 939 00:36:19.469 --> 00:36:21.629 to the sun, hence the cometary type 940 00:36:21.629 --> 00:36:24.629 classification it got. Maybe some 941 00:36:24.629 --> 00:36:26.309 of the material it's ejecting in that 942 00:36:26.309 --> 00:36:28.389 outgassing is being ejected gently enough 943 00:36:28.389 --> 00:36:31.009 that it doesn't escape from Chiron and, 944 00:36:30.959 --> 00:36:33.799 that's repopulating the rings. We just don't 945 00:36:33.799 --> 00:36:36.719 know. But the only way we'll find 946 00:36:36.719 --> 00:36:38.399 out is by doing more of these observations. 947 00:36:38.399 --> 00:36:41.279 But I think it's just really exciting and 948 00:36:41.279 --> 00:36:44.229 it's a really good reminder again that we 949 00:36:44.229 --> 00:36:46.069 always kind of imagine the solar system as a 950 00:36:46.069 --> 00:36:48.429 very sad and boring, placid place where not 951 00:36:48.429 --> 00:36:50.709 much changing anymore because it's four and a 952 00:36:50.709 --> 00:36:52.389 half billion years old. And as you get older, 953 00:36:52.389 --> 00:36:53.949 you Get a bit more sedentary and not much 954 00:36:53.949 --> 00:36:56.829 happens. But in fact it's a reminder that 955 00:36:56.829 --> 00:36:59.269 the solar system's a really dynamic place and 956 00:36:59.349 --> 00:37:01.269 things are constantly influenced, constantly 957 00:37:01.269 --> 00:37:03.429 changing. We talked about it last week. The 958 00:37:03.429 --> 00:37:05.829 ocean on Mimas that is possibly 959 00:37:06.149 --> 00:37:08.469 only 15 million years old. Now, 50 million 960 00:37:08.469 --> 00:37:11.029 years sounds like a really long time, but in 961 00:37:11.029 --> 00:37:12.749 a system that's four and a half thousand 962 00:37:12.749 --> 00:37:15.709 million years old, that's like something 963 00:37:15.709 --> 00:37:17.829 that has happened to me in the last couple of 964 00:37:17.829 --> 00:37:20.389 weeks. That's a new feature, not something 965 00:37:20.389 --> 00:37:22.389 I've had since birth. And this is yet another 966 00:37:22.389 --> 00:37:24.069 example of the fact that the solar system 967 00:37:24.069 --> 00:37:26.709 just seems to be continually rapidly changing 968 00:37:26.709 --> 00:37:27.309 and evolving. 969 00:37:27.789 --> 00:37:29.629 Andrew Dunkley: Yeah, yeah, it's a really interesting 970 00:37:29.789 --> 00:37:32.769 situation. how far out is chiron? 971 00:37:33.809 --> 00:37:36.089 Jonti Horner: It varies. So it's closest to the sun, It's a 972 00:37:36.089 --> 00:37:37.729 little bit closer to the sun than the orbit 973 00:37:37.729 --> 00:37:39.719 of Saturn. at its furthest, it's a bit 974 00:37:39.719 --> 00:37:41.279 further away than the orbit of Uranus. And 975 00:37:41.279 --> 00:37:42.959 that's an unstable orbit. So it bounces 976 00:37:42.959 --> 00:37:45.479 around over time, it will have encounters 977 00:37:45.479 --> 00:37:47.839 with them that fling it around. But at the 978 00:37:47.839 --> 00:37:50.399 minute it's in the outer solar system 979 00:37:50.479 --> 00:37:53.159 between the orbits of Saturn and Uranus most 980 00:37:53.159 --> 00:37:55.679 of the time. Unstable solution. It probably 981 00:37:55.679 --> 00:37:57.719 originated out beyond the orbit of Neptune. 982 00:37:57.719 --> 00:38:00.199 And it's one of this population called the 983 00:38:00.199 --> 00:38:03.059 Centaurs that are, the future parents of the 984 00:38:03.059 --> 00:38:04.699 next generation of short period comets. 985 00:38:04.699 --> 00:38:06.139 Effectively in the same way that the near 986 00:38:06.139 --> 00:38:08.379 Earth asteroids have their origin in the 987 00:38:08.379 --> 00:38:10.939 asteroid belt, short period comets have their 988 00:38:10.939 --> 00:38:13.579 origin in the Transeptunian region. But to 989 00:38:13.579 --> 00:38:15.059 get here from there, they've got to pass 990 00:38:15.059 --> 00:38:16.419 through the outer solar system. And that's 991 00:38:16.419 --> 00:38:17.459 what the Centaurs are. 992 00:38:18.019 --> 00:38:20.299 Andrew Dunkley: Okay. Fascinating. Yeah, it's really 993 00:38:20.299 --> 00:38:22.659 interesting and probably not one that, 994 00:38:23.048 --> 00:38:25.529 too many people would be aware of. I remember 995 00:38:25.529 --> 00:38:28.529 when it was making the news some 996 00:38:28.529 --> 00:38:30.969 years ago, and that's why the name stuck when 997 00:38:30.969 --> 00:38:33.499 you, when you sent the story to me. But, you 998 00:38:33.499 --> 00:38:35.459 don't really hear much about it. But now 999 00:38:35.929 --> 00:38:37.769 we've got a very good reason to look at it. 1000 00:38:38.209 --> 00:38:40.129 if you would like to look into that 1001 00:38:40.129 --> 00:38:43.009 particular paper, it's been published in 1002 00:38:43.009 --> 00:38:45.809 the Astrophysical Journal Letters. 1003 00:38:51.809 --> 00:38:53.729 Our final story, Jonti, is, 1004 00:38:54.689 --> 00:38:57.449 an exoplanet that the popular press are going 1005 00:38:57.449 --> 00:38:59.909 to say has got, some kind of life on it. it's 1006 00:38:59.909 --> 00:39:02.759 a, it's a maybe life candidate, story, 1007 00:39:02.759 --> 00:39:05.749 this one. And Yeah, but they're still 1008 00:39:05.749 --> 00:39:07.309 using the term super Earth. 1009 00:39:07.469 --> 00:39:09.869 Jonti Horner: Yeah, I'll keep this one a little bit short 1010 00:39:09.869 --> 00:39:12.709 and try not to get too grumpy. But one of my 1011 00:39:12.709 --> 00:39:15.549 big bug bears all the way through my career 1012 00:39:15.629 --> 00:39:18.479 is a good way for people to get media 1013 00:39:18.479 --> 00:39:20.679 coverage of their new planet discovery is say 1014 00:39:20.679 --> 00:39:23.119 it could be habitable. It's in the Goldilocks 1015 00:39:23.119 --> 00:39:23.759 zone. Hooray. 1016 00:39:24.079 --> 00:39:25.279 Andrew Dunkley: Using the L word. 1017 00:39:25.599 --> 00:39:27.119 Jonti Horner: Rumble, rumble, grumble, grumble. 1018 00:39:27.199 --> 00:39:28.879 Andrew Dunkley: It's a four letter word too, that one. 1019 00:39:28.879 --> 00:39:30.829 Jonti Horner: It is, and it's one of the terrible four 1020 00:39:30.829 --> 00:39:33.669 letter words. Part of the problem here is 1021 00:39:33.659 --> 00:39:35.499 there's this concept of the Goldilocks zone, 1022 00:39:35.499 --> 00:39:37.019 of the habitable zone, which has become 1023 00:39:37.019 --> 00:39:38.939 really entrenched in the popular 1024 00:39:38.939 --> 00:39:41.139 consciousness. And it's always viewed as 1025 00:39:41.139 --> 00:39:43.539 being this sweet spot for life. And the idea 1026 00:39:43.539 --> 00:39:45.219 is that if you have a planet in the habitable 1027 00:39:45.219 --> 00:39:46.659 zone, it will have liquid water on its 1028 00:39:46.659 --> 00:39:48.739 surface and all sorts of happy life things 1029 00:39:48.739 --> 00:39:51.179 will happen and everything will be good. 1030 00:39:52.169 --> 00:39:54.649 What it actually means is that if you took 1031 00:39:54.649 --> 00:39:56.829 the Earth, as it is today and put it where 1032 00:39:56.829 --> 00:39:59.149 that planet is, the Earth would still 1033 00:39:59.149 --> 00:40:01.869 maintain its liquid water because planets are 1034 00:40:01.869 --> 00:40:04.669 really diverse. If you took Venus and put 1035 00:40:04.669 --> 00:40:06.349 Venus where the Earth is, With Venus's 1036 00:40:06.349 --> 00:40:08.109 current atmosphere, Venus will be too hot to 1037 00:40:08.109 --> 00:40:10.469 have liquid water. But if you observe the 1038 00:40:10.469 --> 00:40:12.589 solar system from a long long way away and 1039 00:40:12.589 --> 00:40:15.079 you discovered Venus on the Earth's 1040 00:40:15.079 --> 00:40:17.729 orbit, it wouldn't look any different to the 1041 00:40:17.729 --> 00:40:19.059 Earth. it's a planet about the size of the 1042 00:40:19.059 --> 00:40:21.069 Earth, sat in the habitable sun. We, it's 1043 00:40:21.069 --> 00:40:23.709 habitable. Hooray. Whereas Venus is actually 1044 00:40:23.709 --> 00:40:25.749 so hot that on the surface it had melt lead. 1045 00:40:25.749 --> 00:40:27.629 And I certainly wouldn't want to visit there. 1046 00:40:27.629 --> 00:40:30.389 It's even hotter than my room was the other 1047 00:40:30.389 --> 00:40:32.869 night when the power cut had happened. And 1048 00:40:32.869 --> 00:40:35.849 that was bad enough and brutal enough. so 1049 00:40:35.849 --> 00:40:38.329 what this means is that ah, people 1050 00:40:38.649 --> 00:40:40.729 have become very fond of 1051 00:40:41.809 --> 00:40:44.609 find a planet around a star, you can work out 1052 00:40:44.849 --> 00:40:46.649 where the boundaries of the habitable zone 1053 00:40:46.649 --> 00:40:48.649 will be based on a few assumptions. And this 1054 00:40:48.649 --> 00:40:51.409 is work going back about a decade of the 1055 00:40:51.409 --> 00:40:53.129 definitions we use now. And you've got the 1056 00:40:53.129 --> 00:40:55.249 conservative and the optimistic habitable 1057 00:40:55.249 --> 00:40:57.399 zone, which are basically loosely based 1058 00:40:57.399 --> 00:40:59.839 around the fact that if you're as close to 1059 00:40:59.839 --> 00:41:02.279 the star that you get an amount of radiation 1060 00:41:02.279 --> 00:41:04.119 coming in comparable to Venus, you'll be too 1061 00:41:04.119 --> 00:41:05.959 hot. If you're about where Mars is, you'll be 1062 00:41:05.959 --> 00:41:07.359 too cold, but in the middle you'll be just 1063 00:41:07.359 --> 00:41:09.899 right m. and that's about it. 1064 00:41:10.059 --> 00:41:12.659 Now that definition doesn't really take any 1065 00:41:12.659 --> 00:41:14.339 account of the mass of the planet or its 1066 00:41:14.339 --> 00:41:17.339 atmosphere. What that 1067 00:41:17.339 --> 00:41:20.099 means is that ah, when you find a planet that 1068 00:41:20.099 --> 00:41:22.139 is a super Earth that Is four times the mass 1069 00:41:22.139 --> 00:41:24.539 of the Earth. That is almost certainly 1070 00:41:24.859 --> 00:41:27.019 nothing like our planet at all. 1071 00:41:27.899 --> 00:41:30.059 You'll do a calculation and say it sits in 1072 00:41:30.059 --> 00:41:32.779 the optimistic habitable zone. So there is a 1073 00:41:32.779 --> 00:41:34.419 potential it could have liquid water on its 1074 00:41:34.419 --> 00:41:37.369 surface. That's full of a whole heap 1075 00:41:37.369 --> 00:41:39.409 of assumptions. But to me it's a really long 1076 00:41:39.409 --> 00:41:41.009 stretch from saying it could have life. 1077 00:41:41.649 --> 00:41:41.969 Andrew Dunkley: A. 1078 00:41:41.969 --> 00:41:43.409 Jonti Horner: You're assuming it's got the right kind of 1079 00:41:43.409 --> 00:41:45.529 atmosphere to have liquid water where it's 1080 00:41:45.529 --> 00:41:46.889 four times the mass of the Earth. So its 1081 00:41:46.889 --> 00:41:48.589 atmosphere is almost certainly much, much m 1082 00:41:48.609 --> 00:41:50.689 thicker, Therefore 1083 00:41:51.329 --> 00:41:53.649 likely has a much stronger greenhouse effect, 1084 00:41:54.049 --> 00:41:55.969 Therefore probably runaway greenhouse. Not 1085 00:41:55.969 --> 00:41:56.289 good. 1086 00:41:56.849 --> 00:41:58.729 The other thing with this particular planet, 1087 00:41:58.729 --> 00:42:01.499 GJ 251C is it's a super 1088 00:42:01.499 --> 00:42:03.639 Earth orbiting a red dwarf star, ah, 1089 00:42:04.259 --> 00:42:06.749 nearby, less than 20 light years away. And 1090 00:42:06.749 --> 00:42:08.389 that's part of why people are excited. It's 1091 00:42:08.389 --> 00:42:09.869 near enough that we'll learn a lot more about 1092 00:42:09.869 --> 00:42:11.909 it in the future. However, 1093 00:42:12.629 --> 00:42:15.069 planet orbiting a red dwarf star means that 1094 00:42:15.069 --> 00:42:16.609 to be in the habitable zone, it's got to be 1095 00:42:16.609 --> 00:42:18.889 close in. This thing goes around its star 1096 00:42:18.889 --> 00:42:21.689 every 54 days, which means that it is 1097 00:42:21.689 --> 00:42:23.729 closer to its star than Mercury is to the 1098 00:42:23.729 --> 00:42:25.769 sun. And given the difference in the masses, 1099 00:42:25.769 --> 00:42:28.239 it's actually much closer in than that. That 1100 00:42:28.239 --> 00:42:30.439 means it's up close and personal with a red 1101 00:42:30.439 --> 00:42:32.759 dwarf star, which are notorious for being 1102 00:42:32.999 --> 00:42:35.479 active and flary and noisy, Particularly when 1103 00:42:35.479 --> 00:42:37.279 they're young. They're tempestuous teenagers 1104 00:42:37.279 --> 00:42:40.239 in their early days with mega stellar flares 1105 00:42:40.239 --> 00:42:43.039 and stuff like this. So it seems to be 1106 00:42:43.039 --> 00:42:44.999 fairly widely accepted that planets around 1107 00:42:44.999 --> 00:42:47.679 red dwarf stars that are close enough to be 1108 00:42:47.679 --> 00:42:50.119 warm enough to have liquid water will have a 1109 00:42:50.119 --> 00:42:51.879 hard time holding onto their atmospheres, 1110 00:42:51.959 --> 00:42:53.119 Particularly when the stars are young, 1111 00:42:53.119 --> 00:42:55.769 because it'll be having all sorts of 1112 00:42:55.769 --> 00:42:57.819 bonkers fun. And that's kind of borne out 1113 00:42:57.899 --> 00:43:00.699 with the planets around Trappist 1, which for 1114 00:43:00.699 --> 00:43:02.939 years have been people saying these are the 1115 00:43:02.939 --> 00:43:04.499 most Earth like planets ever and we'll find 1116 00:43:04.499 --> 00:43:06.899 life on them and hooray. And then when they 1117 00:43:06.899 --> 00:43:08.539 finally got to use the James Webb space 1118 00:43:08.539 --> 00:43:10.739 telescope and look at those planets, none of 1119 00:43:10.739 --> 00:43:13.179 them have an atmosphere. Now I don't know 1120 00:43:13.179 --> 00:43:15.499 about you, but I kind of like to breathe. 1121 00:43:15.659 --> 00:43:17.949 It's a fairly important part of living. And a 1122 00:43:17.949 --> 00:43:19.949 planet without an atmosphere is not going to 1123 00:43:19.949 --> 00:43:21.629 have liquid water on the surface because if 1124 00:43:21.629 --> 00:43:23.029 you take the atmosphere away, there's no 1125 00:43:23.029 --> 00:43:25.769 pressure, the oceans boil and then are blown 1126 00:43:25.769 --> 00:43:28.129 away by the red dwarfs, which makes that 1127 00:43:28.129 --> 00:43:30.249 planet a desiccated husk, which not 1128 00:43:30.249 --> 00:43:32.929 particularly habitable. The reason I Get 1129 00:43:33.169 --> 00:43:35.969 energized and activated about this. It's a 1130 00:43:35.969 --> 00:43:37.729 lovely discovery. It's a really interesting 1131 00:43:37.729 --> 00:43:39.439 planet. We'll, learn a lot more about planets 1132 00:43:39.439 --> 00:43:41.999 elsewhere. If there is an atmosphere, it's 1133 00:43:41.999 --> 00:43:43.639 around us now that's near enough to us that 1134 00:43:43.639 --> 00:43:45.119 with James Webb, we'll be able to study it, 1135 00:43:45.119 --> 00:43:46.599 learn more about the atmosphere. We'll learn 1136 00:43:46.599 --> 00:43:48.759 a whole heap from it. But I get really 1137 00:43:48.759 --> 00:43:50.479 energized about this because there's only so 1138 00:43:50.479 --> 00:43:52.399 many times that people can hear a story that 1139 00:43:52.399 --> 00:43:54.519 says we found the most Earth like planet ever 1140 00:43:55.239 --> 00:43:57.639 before they think we found the Earth before 1141 00:43:57.639 --> 00:44:00.279 they think we found life elsewhere. And that 1142 00:44:00.279 --> 00:44:02.359 then really devalues it. When we finally do 1143 00:44:02.359 --> 00:44:04.799 find planets that are, ah, properly like the 1144 00:44:04.799 --> 00:44:07.439 Earth, when we do find signs of life 1145 00:44:07.439 --> 00:44:09.759 elsewhere, scientists will be getting really 1146 00:44:09.759 --> 00:44:11.279 excited because we've finally done it. And 1147 00:44:11.279 --> 00:44:13.079 everybody will be like, well, why bother? 1148 00:44:13.079 --> 00:44:15.439 You've done this a million times before. The 1149 00:44:15.439 --> 00:44:16.999 whole boy who cried wolf thing 1150 00:44:18.519 --> 00:44:21.199 again, a big bugbear. And something that's 1151 00:44:21.199 --> 00:44:22.759 really critically important these days is 1152 00:44:22.759 --> 00:44:25.629 trust in science and trust in scientists. We, 1153 00:44:25.779 --> 00:44:27.819 we've got all the controversies about topics 1154 00:44:27.819 --> 00:44:29.249 that, are much more controversial than we're 1155 00:44:29.249 --> 00:44:31.369 talking about with astronomy, with vaccine 1156 00:44:31.369 --> 00:44:34.169 denial, with climate change denial, with 1157 00:44:34.169 --> 00:44:36.449 people refusing to evacuate in the path of a 1158 00:44:36.449 --> 00:44:38.409 hurricane that's coming because they don't 1159 00:44:38.409 --> 00:44:41.289 believe the scientists. Anything that 1160 00:44:41.528 --> 00:44:44.009 makes people less trusting of scientists 1161 00:44:44.009 --> 00:44:46.809 because they're overblowing stories is 1162 00:44:46.809 --> 00:44:49.809 damaging now far more than it has been in 1163 00:44:49.809 --> 00:44:51.569 decades past. It's part of why I get so 1164 00:44:51.569 --> 00:44:54.209 frustrated with Avi Loeb and Three Eye Atlas. 1165 00:44:54.209 --> 00:44:56.739 It's why get frustrated with the media 1166 00:44:56.739 --> 00:44:58.259 coverage of stories like this and the 1167 00:44:58.259 --> 00:45:00.819 scientists pushing, I think, somewhat 1168 00:45:00.819 --> 00:45:03.299 unethically an argument that this could be a 1169 00:45:03.299 --> 00:45:06.259 habitable planet because it makes 1170 00:45:06.259 --> 00:45:07.819 the rest of us look like fools. And it makes 1171 00:45:07.819 --> 00:45:10.259 people, it gives them ammunition to say, 1172 00:45:10.259 --> 00:45:12.819 well, scientists lie to us when they're not. 1173 00:45:13.379 --> 00:45:15.339 They're saying that this meets the criteria 1174 00:45:15.339 --> 00:45:16.819 for the Habitable Zone paper that was 1175 00:45:16.819 --> 00:45:19.219 published 10 years ago. But 1176 00:45:19.539 --> 00:45:21.899 it weakens that trust in science, which is so 1177 00:45:21.899 --> 00:45:23.739 important now more than it ever has done. And 1178 00:45:23.739 --> 00:45:25.369 I said I wouldn't go on a run and I'm now 1179 00:45:25.839 --> 00:45:27.719 waving the flag and banging the table and all 1180 00:45:27.719 --> 00:45:30.359 the rest of it. But it's a frustration that's 1181 00:45:30.359 --> 00:45:32.159 wider than this story. And this story is 1182 00:45:32.159 --> 00:45:34.799 lovely. It's an awesome discovery. They found 1183 00:45:34.799 --> 00:45:36.519 a planet going around a star. That's very 1184 00:45:36.519 --> 00:45:38.399 cool. We'll learn a lot more about it. It's a 1185 00:45:38.399 --> 00:45:41.159 brilliant result. You don't need to tag every 1186 00:45:41.159 --> 00:45:43.079 result like this and say that this planet 1187 00:45:43.079 --> 00:45:43.759 could have life. 1188 00:45:45.519 --> 00:45:47.759 Andrew Dunkley: And yet that's what, that's what happens. 1189 00:45:47.719 --> 00:45:49.419 it's sort of like, what artificial 1190 00:45:49.419 --> 00:45:51.619 intelligence is doing to social media. You 1191 00:45:51.619 --> 00:45:53.999 don't know. You don't know what you're 1192 00:45:53.999 --> 00:45:56.719 looking at anymore. And my 1193 00:45:56.719 --> 00:45:59.559 trust levels have dropped significantly in 1194 00:45:59.559 --> 00:46:00.199 recent months. 1195 00:46:02.119 --> 00:46:04.729 Jonti Horner: My dad is, 80, and 1196 00:46:04.729 --> 00:46:06.529 he's still on Facebook. And he doesn't like 1197 00:46:06.529 --> 00:46:08.329 it, but he's on it because it's a way to 1198 00:46:08.329 --> 00:46:10.089 communicate with people back in the uk. Moved 1199 00:46:10.089 --> 00:46:12.609 over here a few years ago and he's constantly 1200 00:46:12.609 --> 00:46:14.529 saying to me, he's getting so frustrated with 1201 00:46:14.529 --> 00:46:16.929 these AI stories and fake news things that he 1202 00:46:16.929 --> 00:46:18.569 doesn't know what to trust on there anymore 1203 00:46:18.649 --> 00:46:21.059 because he'll see a story that some famous 1204 00:46:21.059 --> 00:46:23.659 actors died and then he'll look up on 1205 00:46:23.659 --> 00:46:25.459 Wikipedia and they're still alive and kicking 1206 00:46:25.459 --> 00:46:26.779 and they've got a film coming out. But 1207 00:46:26.779 --> 00:46:28.099 there's this thing of, you'd never believe 1208 00:46:28.099 --> 00:46:31.059 the tragic photos. And it's 1209 00:46:31.059 --> 00:46:33.699 bizarre. And at a time when we need fidelity 1210 00:46:33.699 --> 00:46:36.019 and trust in our news and trust in our 1211 00:46:36.019 --> 00:46:38.979 science, we've got to be careful about how 1212 00:46:38.979 --> 00:46:41.099 much hyperbole we put into stories. I think. 1213 00:46:41.419 --> 00:46:43.979 Andrew Dunkley: I totally agree. Yes. If you'd like to read 1214 00:46:43.979 --> 00:46:46.809 about that, particular exoplanet, you can, 1215 00:46:47.159 --> 00:46:49.619 pick up that yarn through the Astronomical 1216 00:46:49.619 --> 00:46:51.419 Journal where they publish the paper. Or you 1217 00:46:51.419 --> 00:46:53.519 can read up on all the stories we've talked 1218 00:46:53.519 --> 00:46:53.719 about 1219 00:46:53.719 --> 00:46:56.639 today@space.com 1220 00:46:57.199 --> 00:46:59.569 and I'm sure a few other, platforms have 1221 00:46:59.569 --> 00:47:00.569 published them as well. 1222 00:47:01.019 --> 00:47:03.169 and that brings us to the end of, this 1223 00:47:03.409 --> 00:47:05.329 program. Jonti, thank you so much. 1224 00:47:05.969 --> 00:47:07.729 Jonti Horner: It's a pleasure. It's lovely to chat. Thanks 1225 00:47:07.729 --> 00:47:09.609 for bearing with me, being a bit flighty and 1226 00:47:09.609 --> 00:47:11.329 flirty thanks to the power cuts and the 1227 00:47:11.329 --> 00:47:11.649 weather. 1228 00:47:12.529 --> 00:47:15.129 Andrew Dunkley: You've done well. You've done well. We'll, 1229 00:47:15.129 --> 00:47:17.129 catch you on the next program, a Q and A 1230 00:47:17.129 --> 00:47:19.099 program. Johnty, Horn, a professor of 1231 00:47:19.099 --> 00:47:21.419 astrophysics at the University University of 1232 00:47:21.419 --> 00:47:24.079 Southern Queens. And thanks to Huw in the 1233 00:47:24.079 --> 00:47:26.399 studio, who couldn't be with us today 1234 00:47:27.119 --> 00:47:30.119 because he never tells me. I 1235 00:47:30.119 --> 00:47:32.639 have no idea. I just make up the reasons he's 1236 00:47:32.639 --> 00:47:34.839 not here. I honestly don't know why he didn't 1237 00:47:34.839 --> 00:47:36.719 turn up this week. Probably because we didn't 1238 00:47:36.719 --> 00:47:37.839 tell him when we were recording. 1239 00:47:38.319 --> 00:47:39.359 Jonti Horner: That might have been it. 1240 00:47:39.569 --> 00:47:41.769 Andrew Dunkley: and from me, Andrew Dunkley, thanks for your 1241 00:47:41.769 --> 00:47:44.409 company. Catch you on the very next episode 1242 00:47:44.409 --> 00:47:46.049 of Space Nuts. Bye. 1243 00:47:46.049 --> 00:47:46.369 Jonti Horner: Bye. 1244 00:47:47.409 --> 00:47:49.689 You've been listening to the Space Nuts 1245 00:47:49.689 --> 00:47:52.609 podcast, available at 1246 00:47:52.609 --> 00:47:54.569 Apple Podcasts, Spotify, 1247 00:47:54.729 --> 00:47:57.529 iHeartRadio or your favorite podcast 1248 00:47:57.529 --> 00:47:59.889 player. You can also stream on demand at 1249 00:47:59.889 --> 00:48:00.969 bytes. Com. 1250 00:48:01.289 --> 00:48:03.369 Andrew Dunkley: This has been another quality podcast 1251 00:48:03.369 --> 00:48:05.099 production from Bytes. Com.