บทถอดความฉบับเต็มของ Space Questions: Gravity's Pull, Cosmic Debris & Habitability Zones

If the moon's gravitational 42 00:01:43.040 --> 00:01:45.720 pull has such an effect on our Ocean's 43 00:01:45.720 --> 00:01:48.400 tides, for example, a, uh, 30 centimeter 44 00:01:48.400 --> 00:01:51.160 rise in tidal waters twice a day, that's a 45 00:01:51.160 --> 00:01:53.920 lift of 300 kg worth of water per 46 00:01:53.920 --> 00:01:56.760 meter square. Why doesn't the moon's gravity 47 00:01:56.760 --> 00:01:59.400 affect us as drastically as the 48 00:01:59.400 --> 00:02:02.370 oceans? I will sleep better once resolved 49 00:02:02.370 --> 00:02:03.170 with. Thanks. 50 00:02:05.010 --> 00:02:07.450 Oh, so I have so much. I have so much. I feel 51 00:02:07.450 --> 00:02:09.050 like I could say about this one too. But 52 00:02:09.050 --> 00:02:10.050 please get Fred. 53 00:02:11.410 --> 00:02:12.890 Professor Fred Watson: You might give a better answer than me, 54 00:02:12.890 --> 00:02:15.830 Heidi. Um, 55 00:02:15.830 --> 00:02:18.610 so it. Yes, well, it does. The 56 00:02:18.610 --> 00:02:21.250 moon's gravity does affect us as drastically 57 00:02:21.250 --> 00:02:23.050 as the oceans because we go up and down with 58 00:02:23.050 --> 00:02:25.890 the oceans. Uh, in fact, the land itself 59 00:02:25.890 --> 00:02:27.610 goes up and down slightly. If I remember. 60 00:02:27.610 --> 00:02:30.480 It's about a foot or something. Oceans 61 00:02:30.480 --> 00:02:33.320 sometimes go, uh, much, much more 62 00:02:33.320 --> 00:02:35.800 than that. Um, that 30 centimeter that 63 00:02:37.080 --> 00:02:39.840 John mentions. Uh, you know, sometimes it's 64 00:02:39.840 --> 00:02:42.430 many, many meters. So what's, um, 65 00:02:42.840 --> 00:02:45.480 happening here? It's. The critical 66 00:02:45.960 --> 00:02:48.840 feature of tides is that they 67 00:02:48.840 --> 00:02:51.680 are caused because of the 68 00:02:51.680 --> 00:02:54.120 difference in the gravitational pull 69 00:02:54.820 --> 00:02:57.500 of a body like the moon. And let's just think 70 00:02:57.500 --> 00:02:59.570 about the moon and the Earth. Uh, 71 00:03:00.180 --> 00:03:03.060 it's a difference between the moon's pull on 72 00:03:03.060 --> 00:03:06.060 one side of the earth and the other side 73 00:03:06.060 --> 00:03:08.180 of the Earth. So tides are all about 74 00:03:08.820 --> 00:03:10.940 the difference in the gravitational pull of 75 00:03:10.940 --> 00:03:13.740 an object, uh, across the diameter of 76 00:03:13.740 --> 00:03:16.540 another object, a big object, and that's the 77 00:03:16.540 --> 00:03:19.460 Earth. And so, um, the reason why our 78 00:03:19.460 --> 00:03:22.340 bodies don't stretch and shrink is that we're 79 00:03:22.340 --> 00:03:25.300 only, you know, we're only a couple of meters 80 00:03:25.300 --> 00:03:27.940 tall. Uh, actually my son's a two meters 81 00:03:27.940 --> 00:03:29.780 tall, but that's quite tall. All right, one 82 00:03:29.780 --> 00:03:32.100 and a half meters tall. But we're certainly 83 00:03:32.100 --> 00:03:34.780 not, uh, tens of thousands of kilometers, 84 00:03:34.950 --> 00:03:37.060 uh, which is what you need for the 85 00:03:37.060 --> 00:03:39.980 gravitational effect to be noticeable, 86 00:03:40.210 --> 00:03:43.100 um, as it is with the ocean tides. So 87 00:03:43.100 --> 00:03:45.430 we don't get stretched and um, 88 00:03:45.580 --> 00:03:47.740 shrunk. We would if we were near a black 89 00:03:47.740 --> 00:03:48.980 hole. That's the principle of 90 00:03:48.980 --> 00:03:51.580 spaghettification. It's when your feet feel a 91 00:03:51.580 --> 00:03:53.520 higher gravitational pull than your head head 92 00:03:53.520 --> 00:03:56.480 and you get turned into spaghetti. Uh, that's 93 00:03:56.480 --> 00:03:59.240 a uh, tidal effect, uh, an extreme 94 00:03:59.240 --> 00:04:02.000 tidal effect. But um, you need 95 00:04:02.000 --> 00:04:04.160 something very peculiar like a black hole to 96 00:04:04.160 --> 00:04:07.040 notice that. So for, ah, an 97 00:04:07.040 --> 00:04:09.040 object like the moon, we simply just go up 98 00:04:09.040 --> 00:04:11.200 and down with the oceans. If we're on the 99 00:04:11.200 --> 00:04:12.800 ocean, we go up and down with the land if 100 00:04:12.800 --> 00:04:14.720 we're on the land. But we don't get stretched 101 00:04:14.720 --> 00:04:16.280 and shrunk because we're too small. 102 00:04:17.480 --> 00:04:20.120 I hope he's Jonas. I hope you sleep better 103 00:04:20.120 --> 00:04:20.840 after that. 104 00:04:21.990 --> 00:04:23.550 Heidi Campo: Well, maybe I'll scare him because I was 105 00:04:23.550 --> 00:04:26.550 gonna say, but it does affect us 106 00:04:26.550 --> 00:04:29.110 a little bit. Not like the oceans at all. 107 00:04:29.430 --> 00:04:31.830 But the human body is roughly 108 00:04:31.830 --> 00:04:34.670 60% water and every cell in our body is 109 00:04:34.670 --> 00:04:37.670 roughly 70 to 80% water. Now 110 00:04:37.670 --> 00:04:40.190 what I'm about to say next is not something 111 00:04:40.190 --> 00:04:42.070 I'm looking at a science review for. It's 112 00:04:42.070 --> 00:04:44.260 more anecdotal. But, um, 113 00:04:45.030 --> 00:04:47.920 nurses will all stay like often 114 00:04:48.000 --> 00:04:50.850 say that there is way more um, 115 00:04:50.850 --> 00:04:53.040 emergency room activity on a full moon. 116 00:04:53.280 --> 00:04:55.640 Police officers will say that people are 117 00:04:55.640 --> 00:04:58.520 crazier on a full moon. And there's a lot 118 00:04:58.520 --> 00:05:01.360 of lore around women's cycles 119 00:05:01.680 --> 00:05:04.520 aligning, ah, with moon cycles. Um, 120 00:05:04.560 --> 00:05:07.520 more women go into labor and give birth 121 00:05:07.520 --> 00:05:10.080 around the moon cycles. And 122 00:05:10.560 --> 00:05:13.120 historically there is a lot of 123 00:05:13.980 --> 00:05:16.940 um, I guess stories 124 00:05:17.020 --> 00:05:19.940 about personality around moons. You 125 00:05:19.940 --> 00:05:22.660 think of werewolf stories. So humans do. We 126

00:05:22.660 --> 00:05:25.220 are affected by the moon to some degree. And 127 00:05:25.220 --> 00:05:27.180 that would be an interesting, probably 128 00:05:27.260 --> 00:05:29.500 further research. And I'm sure there's whole 129 00:05:29.660 --> 00:05:31.460 departments dedicated to the 130 00:05:31.460 --> 00:05:34.340 psychobiological effects of humans and the 131 00:05:34.340 --> 00:05:37.060 moon. But it is interesting. So no we're not 132 00:05:37.060 --> 00:05:39.500 affected like the oceans but there is 133 00:05:40.060 --> 00:05:41.190 some, something to that. 134 00:05:41.670 --> 00:05:43.550 Professor Fred Watson: Absolutely. Yeah. And you, you, you're quite 135 00:05:43.550 --> 00:05:45.910 right. You know this natural cycles that 136 00:05:45.910 --> 00:05:48.750 align with um, with the moon and, 137 00:05:48.750 --> 00:05:51.030 and it's not just humans as well with things 138 00:05:51.030 --> 00:05:53.830 like coral spawning that's um, very much tied 139 00:05:53.830 --> 00:05:56.790 to lunar phases. Uh and some of that's 140 00:05:56.790 --> 00:05:59.750 not very well understood. Uh, but uh, I think 141 00:05:59.750 --> 00:06:02.470 the thrust of, of John's question is 142 00:06:02.550 --> 00:06:04.950 why, why aren't we being stretched and shrunk 143 00:06:05.110 --> 00:06:07.590 like the oceans are? Uh, perhaps I've got it 144 00:06:07.590 --> 00:06:10.190 wrong. But anyway that's the answer. Um, and 145 00:06:10.190 --> 00:06:10.630 I agree. 146 00:06:16.370 --> 00:06:17.250 Ben: Space nuts. 147 00:06:17.650 --> 00:06:20.570 Heidi Campo: Our next question is an audio 148 00:06:20.570 --> 00:06:23.290 question from Ben. Uh, with our 149 00:06:23.290 --> 00:06:25.530 audio questions. We like to cue those up so 150 00:06:25.530 --> 00:06:27.690 you the listeners can hear their question as 151 00:06:27.690 --> 00:06:30.010 well. I'm just going to give Fred a second to 152 00:06:30.010 --> 00:06:32.970 get his question ready as well and we are 153 00:06:32.970 --> 00:06:35.490 going to play Ben's question for you now. 154 00:06:35.730 --> 00:06:37.890 Ben: Hey guys, uh, it is Ben. 155 00:06:38.260 --> 00:06:40.770 Um, American, living in Mexico. 156 00:06:41.400 --> 00:06:43.450 Um, thanks for answering my last question 157 00:06:43.450 --> 00:06:46.210 about how observatories interrupt 158 00:06:46.210 --> 00:06:48.610 their observing schedules to deal with 159 00:06:48.610 --> 00:06:51.010 transient events. And I've just got a follow 160 00:06:51.010 --> 00:06:53.570 up question. Are there any, 161 00:06:54.530 --> 00:06:57.330 any um, scheduled observing 162 00:06:57.890 --> 00:07:00.290 things that uh, might be immune to these 163 00:07:00.290 --> 00:07:02.830 sorts of interruptions? Um, 164 00:07:03.490 --> 00:07:06.290 I know sometimes uh, there are time sensitive 165 00:07:06.580 --> 00:07:09.140 observations of uh, like 166 00:07:09.140 --> 00:07:11.780 transits or something um, that 167 00:07:11.780 --> 00:07:14.320 astronomers use to determine shapes of ah, 168 00:07:14.340 --> 00:07:17.180 objects and stuff like that that uh, need to 169 00:07:17.180 --> 00:07:18.940 occur at a specific time. So I was thinking 170 00:07:18.940 --> 00:07:21.020 maybe those are something that wouldn't be 171 00:07:21.020 --> 00:07:23.940 interrupted. Um, but yeah, that's 172 00:07:23.940 --> 00:07:26.020 my question. Thanks, loving the show. 173 00:07:26.260 --> 00:07:26.740 Voice Over Guy: Bye. 174 00:07:27.140 --> 00:07:30.100 Professor Fred Watson: That's a great question from Ben. Uh, and 175 00:07:30.260 --> 00:07:33.140 Ben's absolutely right and he's actually 176 00:07:33.600 --> 00:07:36.010 um, highlighted at least one of the uh, 177 00:07:36.420 --> 00:07:37.980 the reasons why you wouldn't interrupt 178 00:07:37.980 --> 00:07:40.840 observ. So um, his original question 179 00:07:40.840 --> 00:07:43.600 was about what we might call target 180 00:07:43.600 --> 00:07:46.440 of opportunity observations where uh, 181 00:07:46.560 --> 00:07:49.280 an observer on the telescope would 182 00:07:50.000 --> 00:07:52.840 stand aside if there was something 183 00:07:52.840 --> 00:07:55.520 like a supernova explosion, uh, that 184 00:07:55.520 --> 00:07:58.160 needed the same instrument uh to 185 00:07:58.160 --> 00:08:00.320 observe it to give us something that was only 186 00:08:00.320 --> 00:08:02.680 going to last for a very short time. And that 187 00:08:02.680 --> 00:08:05.350 happens a lot. Um, the, the, 188 00:08:05.510 --> 00:08:08.350 perhaps the best known of those was back 189 00:08:08.350 --> 00:08:11.270 in 1987 which I remember very well when 190 00:08:11.750 --> 00:08:14.150 that was the last time a naked eye 191 00:08:14.150 --> 00:08:17.110 supernova uh, went off in our skies 192 00:08:17.110 --> 00:08:18.710 down here in the southern hemisphere. It was 193 00:08:18.710 --> 00:08:20.710 in the Large Magellanic Cloud, our nearest 194 00:08:21.000 --> 00:08:23.270 uh, dwarf large dwarf galaxy. 195 00:08:24.320 --> 00:08:26.390 Uh, it was visible to the unaided eye first 196 00:08:26.390 --> 00:08:29.030 for 400 years. Uh and of course 197 00:08:29.110 --> 00:08:31.780 the Telescope, our telescope was only 10 198 00:08:31.780 --> 00:08:34.140 years old then. It was state of the art and 199 00:08:34.220 --> 00:08:35.940 pretty well everything was pushed off for 200 00:08:35.940 --> 00:08:38.060 observations of this, of this object. 201 00:08:38.720 --> 00:08:40.940 Um, but um, it 202 00:08:41.420 --> 00:08:44.340 is usually um, you 203 00:08:44.340 --> 00:08:46.920 know, it's not usually uh, 204 00:08:47.580 --> 00:08:50.540 an event, uh, where there will 205 00:08:50.540 --> 00:08:53.460 be a conflict between the scheduled 206 00:08:53.460 --> 00:08:56.060 observer and the person who was 207 00:08:56.460 --> 00:08:58.460 requiring the target of opportunity 208 00:08:58.460 --> 00:09:01.020 observations. It's uh, usually the 209 00:09:01.020 --> 00:09:03.790

scheduled observer would have uh, uh, 210 00:09:03.790 --> 00:09:06.580 had an understanding at the outset that 211 00:09:07.360 --> 00:09:10.150 uh, they might need to stand by and um, 212 00:09:10.900 --> 00:09:13.460 let somebody else take over the telescope for 213 00:09:13.460 --> 00:09:16.060 the purpose of whatever their observations 214 00:09:16.060 --> 00:09:18.780 are. However, uh, Ben's 215 00:09:18.780 --> 00:09:21.060 absolutely right. There are some observations 216 00:09:21.540 --> 00:09:24.060 which are scheduled which themselves are time 217 00:09:24.060 --> 00:09:26.910 critical. And so you would rule 218 00:09:26.910 --> 00:09:29.470 out the telescope being taken over 219 00:09:30.070 --> 00:09:32.590 uh, for those events. Uh, one I was 220 00:09:32.670 --> 00:09:35.670 involved with, um, because I was astronomer 221 00:09:35.670 --> 00:09:37.910 in charge of the telescope at the time. And 222 00:09:37.910 --> 00:09:39.830 this is probably 10 years ago there was an 223 00:09:39.830 --> 00:09:42.510 occultation of Pluto. 224 00:09:42.950 --> 00:09:45.310 Um, so what that means is 225 00:09:46.230 --> 00:09:48.270 uh, actually it was an occultation of a star 226 00:09:48.270 --> 00:09:50.950 by Pluto. What that means is Pluto passed in 227 00:09:50.950 --> 00:09:53.830 front of a distant star, uh, and 228 00:09:53.830 --> 00:09:55.710 we could observe the brightness of the star. 229 00:09:56.030 --> 00:09:58.430 And what we wanted to do was 230 00:09:59.070 --> 00:10:01.830 look uh, at the way the star's 231 00:10:01.830 --> 00:10:04.750 light um, diminished uh, as 232 00:10:04.750 --> 00:10:06.750 it passed through Pluto's atmosphere. This 233 00:10:06.990 --> 00:10:09.950 actually it was before um, New Horizons 234 00:10:09.950 --> 00:10:12.190 flew by Pluto in 2015. 235 00:10:12.830 --> 00:10:14.990 So we didn't really know much about Pluto's 236 00:10:14.990 --> 00:10:17.350 atmosphere. It's very thin, very tenuous. But 237 00:10:17.350 --> 00:10:18.990 the observations that were made actually 238 00:10:18.990 --> 00:10:21.780 allowed us to um, you know, form 239 00:10:21.780 --> 00:10:23.780 details of it. In particular that it's quite 240 00:10:23.780 --> 00:10:26.300 layered. It's not a smooth, smoothly changing 241 00:10:26.300 --> 00:10:28.660 distribution. So that was very much a time 242 00:10:28.660 --> 00:10:31.140 critical observation. And you would not get 243 00:10:31.700 --> 00:10:33.940 uh, even if there'd been a bright supernova 244 00:10:34.240 --> 00:10:36.740 uh, in the sky that night, it probably would 245 00:10:36.740 --> 00:10:39.020 not have taken over the telescope. I think it 246 00:10:39.020 --> 00:10:40.820 would have, uh, the occultation 247 00:10:42.180 --> 00:10:44.540 by uh, Pluto would have been, would have been 248 00:10:44.540 --> 00:10:46.980 the thing. And as uh, exactly as Ben says, 249 00:10:48.260 --> 00:10:50.540 occultations are when an object passes in 250 00:10:50.540 --> 00:10:52.880

front of a star usually or another object. 251 00:10:53.220 --> 00:10:55.640 Uh, but it's a way of allowing us to work out 252 00:10:55.640 --> 00:10:57.440 the shapes of asteroids and things of that 253 00:10:57.440 --> 00:10:59.960 sort if they pass in front of a star. So 254 00:10:59.960 --> 00:11:02.080 that's really quite, quite important 255 00:11:02.080 --> 00:11:04.600 observations and very much time critical in 256 00:11:04.600 --> 00:11:06.520 themselves. So you wouldn't want them to be 257 00:11:06.520 --> 00:11:08.520 taken over by others. But it's a great 258 00:11:08.520 --> 00:11:08.800 question. 259 00:11:09.360 --> 00:11:11.120 Heidi Campo: It was a really interesting one. Yeah, it 260 00:11:11.120 --> 00:11:12.800 kind of gives us the inner workings of 261 00:11:12.800 --> 00:11:13.520 astronomy. 262 00:11:14.400 --> 00:11:17.000 Our next question, um, I'm actually going to 263 00:11:17.000 --> 00:11:19.840 read two questions because they are 264 00:11:20.160 --> 00:11:22.960 similar, but we want to get both 265 00:11:23.040 --> 00:11:25.760 questions perspectives. So the first one 266 00:11:25.760 --> 00:11:28.600 we're going to read is from David and 267 00:11:28.600 --> 00:11:31.520 David says hello Heidi and Fred. My 268 00:11:31.520 --> 00:11:33.920 question is regarding meteor showers and why 269 00:11:33.920 --> 00:11:36.640 we keep seeing them annually. If meteor 270 00:11:36.640 --> 00:11:39.600 showers such as Persidius occur 271 00:11:39.600 --> 00:11:42.520 when the Earth passes through the debris left 272 00:11:42.520 --> 00:11:45.280 behind by comets as they orbit the 273 00:11:45.280 --> 00:11:48.000 sun, what prevents the Earth from clearing 274 00:11:48.000 --> 00:11:51.000 the debris from our orbital path after 275 00:11:51.000 --> 00:11:53.800 the first pass, leaving our orbit free of 276 00:11:53.800 --> 00:11:56.780 debris until the next comet pass, uh, uh, 277 00:11:56.780 --> 00:11:59.180 next comet comes past. Cheers 278 00:11:59.340 --> 00:12:01.820 Dave. And then we have 279 00:12:02.140 --> 00:12:04.460 Brian with his question which is similar. 280 00:12:05.740 --> 00:12:08.540 And then Brian says, can you explain the 281 00:12:08.540 --> 00:12:11.260 orbital dynamics associated with annual 282 00:12:11.260 --> 00:12:14.180 meteor showers? We orbit the sun, but 283 00:12:14.180 --> 00:12:16.500 the whole solar system is rotating around the 284 00:12:16.500 --> 00:12:19.500 Milky Way, which itself is moving. So 285 00:12:19.500 --> 00:12:22.460 is the comet trail in a static stripe of 286 00:12:22.460 --> 00:12:25.300 debris which we bisect on the same 287 00:12:25.300 --> 00:12:27.880 point in our orbit total in our orbit each 288 00:12:27.880 --> 00:12:30.800 year or is it in the orbit 289 00:12:30.800 --> 00:12:33.400 of the sun or a galactic 290 00:12:33.400 --> 00:12:36.360 center or other? If it's in our 291 00:12:36.360 --> 00:12:39.320 solar orbit, why do we catch up with it? And 292 00:12:39.320 --> 00:12:41.840 why don't we effectively leave a hole in the 293 00:12:41.840 --> 00:12:44.680 debris diminishing the meteors every year 294 00:12:45.080 --> 00:12:47.640 from the dark state, uh, from the dark 295 00:12:47.720 --> 00:12:50.440 stars. North Yorkshire Moons 296 00:12:50.600 --> 00:12:51.560 National Park. 297 00:12:53.010 --> 00:12:56.010 Professor Fred Watson: Yeah, the national, It's North Yorkshire, um, 298 00:12:56.010 --> 00:12:58.250 Moors National Park. It's a place I know well 299 00:12:58.250 --> 00:13:01.090 in fact, uh, in the north of England and 300 00:13:01.170 --> 00:13:04.090 they do have dark sky, dark stars. Uh, this 301 00:13:04.090 --> 00:13:06.130 is from Brian there. I wonder whether Brian 302 00:13:06.130 --> 00:13:08.330 knows my friend Paul Cass who also works at 303 00:13:08.330 --> 00:13:11.090 the North Yorkshire Moors Dark Sky 304 00:13:11.090 --> 00:13:13.530 Park. Anyway, that's a different uh, aspect 305 00:13:13.530 --> 00:13:16.250 of all this Heidi. Um, and I might mention 306 00:13:16.250 --> 00:13:19.000 that um, they've uh. Dave who 307 00:13:19.000 --> 00:13:19.280 had. 308 00:13:19.280 --> 00:13:21.160 The other question was from, from Inverell 309 00:13:21.160 --> 00:13:23.400 here in New South Wales. So a question from 310 00:13:23.400 --> 00:13:25.600 the UK and a question from Australia, both 311 00:13:25.600 --> 00:13:27.800 effectively asking the same thing which I 312 00:13:27.800 --> 00:13:30.680 thought was uh, worth while bringing 313 00:13:30.680 --> 00:13:33.520 these two people together. So yes, 314 00:13:33.520 --> 00:13:35.400 the, the bottom line is, and you've got to 315 00:13:35.400 --> 00:13:38.360 sort of think of it in three dimensions, um, 316 00:13:38.360 --> 00:13:41.040 it is to do with the orbits of 317 00:13:41.040 --> 00:13:43.440 comets. Uh, a uh, comet 318 00:13:44.000 --> 00:13:46.780 moves in a usually a very elongated 319 00:13:46.780 --> 00:13:49.620 orbit. Um, and the sun is um, one 320 00:13:49.620 --> 00:13:52.580 end of um, uh, passes close to 321 00:13:52.580 --> 00:13:55.300 the sun and then disappears into the depths 322 00:13:55.300 --> 00:13:57.860 of the solar system. Uh, when it gets near 323 00:13:57.860 --> 00:14:00.260 the sun, uh, the comet starts 324 00:14:00.899 --> 00:14:03.820 basically projecting dust, uh, 325 00:14:03.860 --> 00:14:06.860 and that dust trail remains within 326 00:14:06.860 --> 00:14:09.340 the comet's orbit. And so those dust 327 00:14:09.340 --> 00:14:12.180 particles are sort of moving with the 328 00:14:12.180 --> 00:14:14.220 comet. They're um, moving in the orbit as 329 00:14:14.220 --> 00:14:15.980 well. But they smear out because they've got 330 00:14:15.980 --> 00:14:18.660 their own uh, motion. And so 331 00:14:19.380 --> 00:14:21.740 essentially ah, a comet leaves a trail of 332 00:14:21.740 --> 00:14:24.620 dust exactly in its orbit and 333 00:14:24.620 --> 00:14:27.540 if that orbit intersects

the Earth's orbit, 334 00:14:27.940 --> 00:14:29.980 then the Earth will pass through the trail of 335 00:14:29.980 --> 00:14:32.620 dust. And that's exactly what it does. And 336 00:14:32.620 --> 00:14:34.500 when that happens, that's when we get a 337 00:14:34.500 --> 00:14:36.980 meteor shower. But the reason why, 338 00:14:37.340 --> 00:14:39.500 um, you know, it doesn't soak up all the dust 339 00:14:39.820 --> 00:14:42.780 as it goes through is because that dust 340 00:14:42.780 --> 00:14:45.400 itself is moving. Uh, and, um, 341 00:14:45.420 --> 00:14:48.060 it's not just a single dust cloud that you're 342 00:14:48.140 --> 00:14:51.060 punching a hole in. The dust is a stream of 343 00:14:51.060 --> 00:14:53.219 stuff that's moving through space with the 344 00:14:53.219 --> 00:14:55.500 same velocity, more or less as the comet had. 345 00:14:55.930 --> 00:14:58.420 Uh, and so what you've got is a region of 346 00:14:58.420 --> 00:15:00.940 space that's rich in dust, but it's being 347 00:15:00.940 --> 00:15:03.780 replenished, um, by the motion of the 348 00:15:03.780 --> 00:15:05.860 particles. So, yes, the Earth plows through, 349 00:15:06.470 --> 00:15:08.620 uh, doesn't really make a hole in it because, 350 00:15:09.480 --> 00:15:12.120 you know, we only sweep up, 351 00:15:12.170 --> 00:15:14.840 um, 12,000 km diameter 352 00:15:15.320 --> 00:15:17.360 worth of it, because that's the Earth's 353 00:15:17.360 --> 00:15:20.120 diameter. Um, and the dust stream might 354 00:15:20.120 --> 00:15:23.080 be many, uh, tens of thousands 355 00:15:23.080 --> 00:15:25.370 and perhaps even millions of kilometers, uh, 356 00:15:25.400 --> 00:15:27.560 wide. Maybe not millions, but certainly 357 00:15:28.440 --> 00:15:31.240 tens, hundreds of thousands, possibly. 358 00:15:31.400 --> 00:15:34.040 So you've got a wide trail of dust that is 359 00:15:34.280 --> 00:15:37.280 a reservoir for the Earth to 360 00:15:37.280 --> 00:15:40.080 sweep up and see the meteor showers. So 361 00:15:40.080 --> 00:15:41.860 it's constantly being replenish. That's the 362 00:15:41.860 --> 00:15:44.020 bottom line. Uh, and hopefully that's the 363 00:15:44.020 --> 00:15:46.180 answer to both those gentlemen's questions. 364 00:15:47.060 --> 00:15:47.170 Voice Over Guy: Oh. 365 00:15:47.170 --> 00:15:49.140 Heidi Campo: Ah, that is fantastic, Fred. 366 00:15:51.620 --> 00:15:53.780 Generic: Okay, we checked all four systems, and. 367 00:15:53.780 --> 00:15:56.220 Heidi Campo: Being with a girl, space nuts, I'm getting 368 00:15:56.220 --> 00:15:56.620 sad. 369 00:15:56.620 --> 00:15:58.700 I'm gonna do my last question now. Unless. 370 00:15:58.700 --> 00:16:01.620 Unless I'm back next week. We will see. 371 00:16:01.940 --> 00:16:04.460 So backstory for. For um, those of you who 372 00:16:04.460 --> 00:16:06.220 might be new listeners, our regular host, 373 00:16:06.220 --> 00:16:07.900 Andrew. He's been on a cruise around the 374 00:16:07.900 --> 00:16:10.840 world

and he's back now, but he 375 00:16:10.840 --> 00:16:13.230 has quite the conundrum. Uh, 376 00:16:14.040 --> 00:16:16.000 getting settled back in. We'll let him tell 377 00:16:16.000 --> 00:16:18.720 you all that story and him and Fred get 378 00:16:18.720 --> 00:16:21.400 caught up when. When he is back. But he's had 379 00:16:21.400 --> 00:16:22.520 quite an exciting time. 380 00:16:23.000 --> 00:16:25.960 All right, so our last question is. Excuse 381 00:16:25.960 --> 00:16:28.920 me. An audio question from Lou. 382 00:16:29.400 --> 00:16:31.720 Voice Over Guy: Hello, Heidi, and, um, Fred. My name is Noah 383 00:16:31.720 --> 00:16:34.440 from Manchester, England. I'm asking 384 00:16:34.520 --> 00:16:36.780 question about the Goldilocks Zone. The 385 00:16:36.860 --> 00:16:39.780 Goldilocks Zone is only habitable for 386 00:16:39.780 --> 00:16:42.020 life on, uh, Earth. For estrus rescues, 387 00:16:42.020 --> 00:16:44.660 however, they might need to exist at the very 388 00:16:44.660 --> 00:16:47.140 edge of the solar system or at the very 389 00:16:47.140 --> 00:16:49.860 center of it. Is the Goldilocks Zone nearly 390 00:16:49.860 --> 00:16:52.220 compatible for all life in the universe? Love 391 00:16:52.220 --> 00:16:53.980 the podcast. Hope you keep making more. 392 00:16:54.460 --> 00:16:57.060 Professor Fred Watson: Lovely question from Lou. Um, Manchester, 393 00:16:57.060 --> 00:16:59.300 again, a place I know well. I grew up not 394 00:16:59.300 --> 00:17:01.140 very far from Manchester in the north of 395 00:17:01.140 --> 00:17:03.820 England. So this has been a bit of, a, bit of 396 00:17:03.820 --> 00:17:06.649 a nostalgia segment for me. Um, but the 397 00:17:06.649 --> 00:17:09.449 great question, uh, you know, is the, is 398 00:17:09.449 --> 00:17:12.409 the Goldilocks Zone applicable to all 399 00:17:12.649 --> 00:17:15.609 extraterrestrial life? And I think the answer 400 00:17:15.609 --> 00:17:18.489 is no. Uh, because 401 00:17:19.049 --> 00:17:21.889 we, when we talk about the Goldilocks Zone, 402 00:17:21.889 --> 00:17:24.849 it's that region surrounding a star where 403 00:17:24.849 --> 00:17:27.249 the temperature is not too hot and it's not 404 00:17:27.249 --> 00:17:29.769 too cold, but it's just right for, for life 405 00:17:29.769 --> 00:17:32.209 to exist. It's why it's called the Goldilocks 406 00:17:32.209 --> 00:17:33.969 Zone. I've got a feeling it was a colleague 407 00:17:33.969 --> 00:17:36.169 of mine who coined that expression as well. A 408 00:17:36.169 --> 00:17:38.990 long, long, um, uh, 409 00:17:39.750 --> 00:17:41.830 it relies on the fact 410 00:17:42.550 --> 00:17:45.550 that we are, ah, beings. In 411 00:17:45.550 --> 00:17:47.430 fact, all life on Earth is 412 00:17:47.790 --> 00:17:50.790 uh, based uh, on water. We use water 413 00:17:51.430 --> 00:17:53.970 as our working fluid. Uh, 414 00:17:54.310 --> 00:17:57.190 as you mentioned, um, in our question on 415 00:17:57.190 --> 00:18:00.030 tides, Heidi, most of our bodies are made of 416 00:18:00.030 --> 00:18:02.870 water. Uh, and the same is 417 00:18:02.870 --> 00:18:05.670 true of most living organisms. Uh, water 418 00:18:05.670 --> 00:18:08.430 is a large part of it. And so 419 00:18:08.670 --> 00:18:11.470 liquid, uh, water is for us, 420 00:18:12.130 --> 00:18:12.990 uh, the, 421 00:18:14.670 --> 00:18:17.310 perhaps the strongest feature that 422 00:18:18.210 --> 00:18:20.590 um, might be used 423 00:18:22.110 --> 00:18:24.910 as an indicator of where life might form. If 424 00:18:24.910 --> 00:18:27.150 you've got water, maybe you will have life. 425 00:18:27.870 --> 00:18:29.990 That's always been the mantra. Follow the 426 00:18:29.990 --> 00:18:32.550 water. Um, so the 427 00:18:32.550 --> 00:18:35.030 Goldilocks Zone is where you could put a 428 00:18:35.030 --> 00:18:37.150 planet and it would be capable of having 429 00:18:37.150 --> 00:18:39.870 liquid water on its surface. Not frozen, not 430 00:18:39.870 --> 00:18:42.510 vapor, but liquid, which is what we need. 431 00:18:42.990 --> 00:18:45.950 So it's very specific is the Goldilocks Zone 432 00:18:45.950 --> 00:18:48.670 to um, life forms that are like 433 00:18:48.670 --> 00:18:51.470 ourselves, that are based on water and. 434 00:18:51.550 --> 00:18:53.830 Yeah, well, maybe if there is life anywhere 435 00:18:53.830 --> 00:18:55.870 else in the universe, it will be based on 436 00:18:55.870 --> 00:18:58.230 water. But there are other possibilities as 437 00:18:58.230 --> 00:19:00.230 well. And people have wondered whether 438 00:19:00.550 --> 00:19:02.870 perhaps the season lakes of Titan, 439 00:19:03.430 --> 00:19:06.430 one of Saturn's moons, uh, whether. Which 440 00:19:06.430 --> 00:19:08.750 are made of liquid ethane and methane, 441 00:19:08.750 --> 00:19:11.030 whether they might have, uh, living 442 00:19:11.430 --> 00:19:13.510 creatures in them that rely on those 443 00:19:13.990 --> 00:19:16.710 supercooled liquids as their working fluid. 444 00:19:16.710 --> 00:19:18.990 We don't know. We've not seen any evidence of 445 00:19:18.990 --> 00:19:21.710 that. But it is possible. And so if that was 446 00:19:21.710 --> 00:19:23.910 the case, then you'd be looking at entirely 447 00:19:23.910 --> 00:19:26.580 different type of Goldilocks Zone. If 448 00:19:26.580 --> 00:19:28.580 liquid natural gas was what you needed, 449 00:19:29.560 --> 00:19:32.060 uh, for these creatures, uh, then your 450 00:19:32.060 --> 00:19:34.340 Goldilocks Zone will be a very different one 451 00:19:34.580 --> 00:19:36.780 from the one that we have. It will be much 452 00:19:36.780 --> 00:19:38.940 further from your parent star. Uh, so 453 00:19:38.940 --> 00:19:41.060 Goldilocks Zones are not universal. They're 454 00:19:41.060 --> 00:19:43.780 not, um, kind uh, of, you know, common 455 00:19:44.100 --> 00:19:47.020 to all species because 456 00:19:47.020 --> 00:19:49.300 we don't know enough about what other species 457

00:19:49.300 --> 00:19:52.140 might be like. But it's a good start. That's 458 00:19:52.140 --> 00:19:54.060 why we look at the Goldilocks Zone with 459 00:19:54.060 --> 00:19:56.840 interest because the only life forms that we 460 00:19:56.840 --> 00:19:59.800 know use water. Uh, and Goldilocks 461 00:19:59.800 --> 00:20:02.080 Zone is where water might exist. So that's 462 00:20:02.080 --> 00:20:02.880 why we look there. 463 00:20:04.080 --> 00:20:06.680 Heidi Campo: Fred, have you ever seen that TV show, I 464 00:20:06.680 --> 00:20:09.120 think it's on Netflix or Amazon, called 465 00:20:09.120 --> 00:20:12.040 Alien Worlds, where they. They break 466 00:20:12.040 --> 00:20:14.440 down scientifically the conditions that would 467 00:20:14.440 --> 00:20:16.360 be needed for. For different life on 468 00:20:16.360 --> 00:20:18.720 different planets. Then they hypothetically 469 00:20:18.800 --> 00:20:21.720 come up with a planet that's a 470 00:20:21.720 --> 00:20:22.800 certain way. Have you seen it? 471 00:20:23.340 --> 00:20:25.070 Professor Fred Watson: M. I haven't, but it sounds like one that I 472 00:20:25.070 --> 00:20:25.750 ought to see. 473 00:20:26.310 --> 00:20:28.990 Heidi Campo: It's very interesting. And that might be one 474 00:20:28.990 --> 00:20:30.990 that Lou's interested in, because they come 475 00:20:30.990 --> 00:20:33.390 up with four hypothetical planets. One of 476 00:20:33.390 --> 00:20:35.790 them's a jungle, one of them's a desert. One 477 00:20:35.790 --> 00:20:38.430 of them is, um, the 478 00:20:38.430 --> 00:20:41.430 atmosphere is so dense that it's 479 00:20:41.430 --> 00:20:44.350 almost like water. So there's all these 480 00:20:44.350 --> 00:20:47.310 animals that look marine like, but they are 481 00:20:47.310 --> 00:20:49.870 like birds. And it's very cool just to play 482 00:20:49.870 --> 00:20:52.790 around because they use real physics and then 483 00:20:52.790 --> 00:20:54.630 talk about the hypothetics. It's kind of fun. 484 00:20:54.770 --> 00:20:56.330 Then I won't tell you about the last planet, 485 00:20:56.330 --> 00:20:58.410 because it's kind of a. It's a fun surprise. 486 00:20:58.410 --> 00:21:00.450 It's a fun surprise planet. It's not Earth. 487 00:21:00.530 --> 00:21:03.330 It's not Earth. Um, it's a very 488 00:21:03.330 --> 00:21:06.330 interesting hypothetical planet. Um, but I do 489 00:21:06.330 --> 00:21:07.250 recommend that show. 490 00:21:08.130 --> 00:21:10.689 Professor Fred Watson: Sounds great. I'll check it out. Sounds, 491 00:21:10.689 --> 00:21:11.250 Heidi. 492 00:21:11.330 --> 00:21:12.370 Heidi Campo: Yeah, it's a good one. 493 00:21:13.000 --> 00:21:15.970 Um, well, I guess that's it for our Q 494 00:21:15.970 --> 00:21:18.290 and A episode. So I just want to say, if this 495 00:21:18.290 --> 00:21:20.730 is my last episode, that it has been an 496 00:21:20.730 --> 00:21:23.130 absolute pleasure and delight being on here. 497 00:21:23.130 --> 00:21:25.690 Thank you all for your wonderful and kind 498 00:21:25.690 --> 00:21:27.990 questions. Fred, thank you for having me. If 499 00:21:27.990 --> 00:21:29.830 y' all want to stay in touch, you can follow 500 00:21:29.830 --> 00:21:32.710 me on LinkedIn. My. It's just my name, Heidi 501 00:21:32.710 --> 00:21:35.710 Campo, which is C, A, M, M, P, O. 502 00:21:35.710 --> 00:21:37.910 And then I think it's on. There is comma, C 503 00:21:37.910 --> 00:21:40.270 S, C S, which is one of my certifications. 504 00:21:40.670 --> 00:21:43.590 That would be Comet sun, if we're spelling 505 00:21:43.590 --> 00:21:46.190 it phonetically. Comet son. Comet son. So, 506 00:21:46.190 --> 00:21:48.310 Heidi Campos, C.S.C.S. if you want to follow 507 00:21:48.310 --> 00:21:50.950 me on LinkedIn, I'm also on Instagram, but 508 00:21:50.950 --> 00:21:53.030 it's mostly just pictures of my dog and me 509 00:21:53.030 --> 00:21:55.230 talking about fitness stuff, which may not be 510 00:21:55.230 --> 00:21:57.960 everybody's cup of tea. Um, Fred, 511 00:21:57.960 --> 00:21:59.560 it's been a delight. Thank you. 512 00:22:00.440 --> 00:22:03.160 Professor Fred Watson: Oh, it's been a delight for me too, Heidi. 513 00:22:03.160 --> 00:22:06.040 And, um, I hope we do this again sometime. 514 00:22:06.120 --> 00:22:08.480 It might be next week, but. It might be next 515 00:22:08.480 --> 00:22:08.640 week. 516 00:22:08.640 --> 00:22:11.120 Heidi Campo: It might be next week. Yeah, we'll be in 517 00:22:11.120 --> 00:22:13.000 touch. And I'm. I'm always here if you need 518 00:22:13.000 --> 00:22:15.080 me. Um, till then, 519 00:22:15.640 --> 00:22:17.560 we'll catch, uh, you all next time. 520 00:22:17.800 --> 00:22:18.360 Professor Fred Watson: Take care. 521 00:22:20.600 --> 00:22:23.400 Voice Over Guy: To the Space Nuts podcast, Mission complete 522 00:22:23.400 --> 00:22:26.050 Eastern. Available at Apple, Apple Podcasts, 523 00:22:26.050 --> 00:22:28.650 Spotify, iHeartRadio, or your 524 00:22:28.650 --> 00:22:31.170 favorite podcast player. You can also stream 525 00:22:31.170 --> 00:22:34.090 on demand at bitesz.com this. Has been 526 00:22:34.090 --> 00:22:36.450 another quality podcast production from 527 00:22:36.450 --> 00:22:37.570 bitesz.com