WEBVTT 1 00:00:03.399 --> 00:00:07.719 Welcome to Bedtime Astronomy. Explore the wonders of the cosmos 2 00:00:07.759 --> 00:00:12.279 with our soothing Bedtime Astronomie podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.839 slumber under the night sky. 7 00:00:26.879 --> 00:00:29.800 Hello, and welcome back to our exploration of the fascinating 8 00:00:29.800 --> 00:00:33.799 world of science and discovery. It is Tuesday, February seventeenth, 9 00:00:33.880 --> 00:00:38.439 twenty twenty six, and today we are we're pointing our 10 00:00:38.479 --> 00:00:40.399 attention upward, way up. 11 00:00:40.479 --> 00:00:43.159 We are. Indeed, we're looking at our nearest neighbor, the 12 00:00:43.200 --> 00:00:47.880 celestial body that has captivated humanity since we first looked 13 00:00:47.920 --> 00:00:48.640 up at the night sky. 14 00:00:48.759 --> 00:00:51.479 The Moon. It's the ultimate constant, right You look up 15 00:00:51.520 --> 00:00:53.479 at night, and there it is. Sometimes it's a sliver, 16 00:00:53.759 --> 00:00:56.439 sometimes it's a big, bright orb, but it's always there. 17 00:00:56.520 --> 00:00:59.600 It's comforting, it's reliable, and I think if you ask 18 00:00:59.679 --> 00:01:01.560 the app rich person on the street, or even me 19 00:01:01.679 --> 00:01:05.079 honestly before reading this material, to describe the Moon's geology, 20 00:01:05.120 --> 00:01:06.400 they probably say it's a done. 21 00:01:06.200 --> 00:01:09.400 Deal, a fossil that's the word that's often used in textbooks. 22 00:01:09.439 --> 00:01:13.359 A planetary fossil exactly, a big, silent, gray rock where 23 00:01:13.439 --> 00:01:16.079 nothing has really happened since the dinosaurs were wiped out, 24 00:01:16.280 --> 00:01:18.920 maybe even longer. You see the craters, the dark spots, 25 00:01:18.920 --> 00:01:21.400 and you figure, okay, that's the furniture. It hasn't been 26 00:01:21.439 --> 00:01:23.640 rearranged in billions of years. 27 00:01:23.760 --> 00:01:26.200 It feels static unchanging. 28 00:01:26.519 --> 00:01:30.079 It does. But the source material we are unpacking today 29 00:01:30.719 --> 00:01:33.959 is going to dismantle that idea pretty thoroughly. It turns 30 00:01:33.959 --> 00:01:38.840 out that dead is a very relative term in planetary science. 31 00:01:39.000 --> 00:01:41.879 It absolutely is, and this new study really drives that 32 00:01:41.959 --> 00:01:46.120 point home. We're learning that our quiet neighbor is well, 33 00:01:46.400 --> 00:01:47.519 not so quiet. 34 00:01:47.239 --> 00:01:50.439 Not at all. We have a fascinating new study here 35 00:01:50.640 --> 00:01:53.159 published in the Planetary Science Journal, coming from a team 36 00:01:53.200 --> 00:01:55.519 at the National Air and Space Museum Center for Earth 37 00:01:55.560 --> 00:01:57.959 and Planetary Studies, and the headline is not just that 38 00:01:58.000 --> 00:02:00.719 the moon is active, is that the Moon is actively 39 00:02:00.760 --> 00:02:03.719 shrinking and shaking. Don't forget the shaking, right, It's getting 40 00:02:03.799 --> 00:02:06.719 smaller and it's trembling while it's doing it. So our 41 00:02:06.719 --> 00:02:09.599 mission for this discussion is to unpack this incredible global 42 00:02:09.639 --> 00:02:12.759 map and analysis produced by these scientists. We're going to 43 00:02:12.800 --> 00:02:16.120 talk about a specific geological feature called small mare ridges 44 00:02:16.560 --> 00:02:19.080 or SMRs for sure SMRs ye, And we're going to 45 00:02:19.080 --> 00:02:21.840 figure out why the Moon is wrinkling up like a raisin, 46 00:02:22.199 --> 00:02:25.120 and more importantly, what that actually means for the humans 47 00:02:25.120 --> 00:02:26.000 we are planning. 48 00:02:25.680 --> 00:02:28.560 To send back there, because it really changes the risk profile. 49 00:02:28.639 --> 00:02:31.199 It changes it significantly for future explorers. 50 00:02:31.479 --> 00:02:35.400 So let's start with the discovery itself. The study centers 51 00:02:35.439 --> 00:02:38.639 on these small mirror ridges. I love a good acronym, 52 00:02:38.639 --> 00:02:40.800 so we're calling them SMRs. But before we get into 53 00:02:40.800 --> 00:02:44.360 the numbers, help me visualize this. If I'm an astronaut 54 00:02:44.439 --> 00:02:47.240 standing on the Moon looking at an SMR, what am 55 00:02:47.240 --> 00:02:48.240 I actually seeing? 56 00:02:48.800 --> 00:02:51.960 Okay? So to visualize this, you have to understand the landscape. First, 57 00:02:52.599 --> 00:02:56.639 the Moon basically has two types of terrain. Very broadly speaking, 58 00:02:57.159 --> 00:02:59.960 you have the highlands, the bright parts. The bright parts exact, 59 00:03:00.439 --> 00:03:04.479 they're rugged, heavily cratered, mountainous areas. Think of the man 60 00:03:04.520 --> 00:03:06.840 in the moon's face. The light parts. This is the 61 00:03:06.919 --> 00:03:08.520 ancient original crust of the moon. 62 00:03:08.560 --> 00:03:10.759 Okay, the rugged white parts, got it. 63 00:03:10.800 --> 00:03:13.360 And then you have the Maria, the seas from the 64 00:03:13.479 --> 00:03:16.479 Latin Maria is Latin four seas. Yes, these are the dark, 65 00:03:16.599 --> 00:03:18.800 flat plains that make up the other features of the 66 00:03:18.800 --> 00:03:22.400 Man in the Moon. Ancient astronomers looking through early telescopes 67 00:03:22.599 --> 00:03:24.680 thought they were actual bodies of water because they look 68 00:03:24.759 --> 00:03:26.400 so smooth compared to the mountains. 69 00:03:26.479 --> 00:03:30.039 But they're not water, no, not at all. 70 00:03:29.319 --> 00:03:33.680 We know now. They are vast solidified lava flows, mostly basalt, 71 00:03:34.039 --> 00:03:34.879 very dark rock. 72 00:03:35.240 --> 00:03:37.800 Okay, so I'm standing in the middle of a basalt plain. 73 00:03:38.639 --> 00:03:41.319 It's dark, it's flat, it's covered in that fine dust. 74 00:03:41.759 --> 00:03:44.680 It's supposed to be the flattest, smoothest part of the Moon, right, 75 00:03:44.759 --> 00:03:46.000 the easy place to land. 76 00:03:46.159 --> 00:03:49.080 That's been the assumption. Yes, for a long time, we 77 00:03:49.080 --> 00:03:52.360 thought it was relatively featureless, you know, barring the occasional 78 00:03:52.439 --> 00:03:56.599 impact crater. But this study, led by col Nikofhr and 79 00:03:56.719 --> 00:04:01.599 Tom Waters, has produced the first globe map of these SMRs. 80 00:04:01.719 --> 00:04:02.719 And what would it look like. 81 00:04:02.960 --> 00:04:05.639 If you were standing there. You wouldn't see a giant 82 00:04:05.680 --> 00:04:09.560 mountain range like the Rockies. You'd see a ridge wrinkle 83 00:04:09.599 --> 00:04:10.199 in the ground. 84 00:04:10.759 --> 00:04:12.560 How big are we talking? Is it like a speed 85 00:04:12.599 --> 00:04:14.879 bumph or more like a hill. 86 00:04:14.919 --> 00:04:18.879 Bigger than a speed bump. They are small in planetary terms, 87 00:04:18.879 --> 00:04:20.680 that's why they have that name. But they would be 88 00:04:20.680 --> 00:04:23.160 pretty substantial if you're trying to hike over one. We're 89 00:04:23.199 --> 00:04:26.800 talking about scarps, which are cliffs or steep slopes that 90 00:04:26.920 --> 00:04:29.120 might rise tens of meters high tens. 91 00:04:28.839 --> 00:04:31.360 Of meters, so like a multi story building exactly. 92 00:04:31.360 --> 00:04:34.240 And they're not just little mounds. They can extend for kilometers, 93 00:04:34.279 --> 00:04:35.720 winding across the landscape. 94 00:04:35.759 --> 00:04:37.839 It's like a long winding wall or a buckle in 95 00:04:37.879 --> 00:04:39.759 the pavement, just on a massive scale. 96 00:04:39.920 --> 00:04:41.839 That's a great way to think of it, a buckle 97 00:04:41.879 --> 00:04:44.839 in the lunar pavement. But what makes this study such 98 00:04:44.839 --> 00:04:47.879 a breakthrough isn't just identifying one or two of these. 99 00:04:47.920 --> 00:04:51.160 I mean, we've seen oddities before. It's the sheer volume, 100 00:04:51.360 --> 00:04:52.560 the number of them. 101 00:04:53.079 --> 00:04:55.040 I was looking at the data table and the report 102 00:04:55.199 --> 00:04:58.519 and the numbers are just startling. They identified eleven one 103 00:04:58.600 --> 00:05:01.800 hundred and fourteen new SMR segments. 104 00:05:01.480 --> 00:05:03.879 Just on the near side lunar Maria, the side that 105 00:05:03.920 --> 00:05:04.600 faces us. 106 00:05:04.800 --> 00:05:07.720 That's over a thousand geological features that we just we 107 00:05:07.720 --> 00:05:08.959 hadn't cataloged them before. 108 00:05:08.759 --> 00:05:12.160 We hadn't mapped them systematically, We didn't understand how widespread 109 00:05:12.199 --> 00:05:14.839 they were. And when you add these new findings to 110 00:05:15.160 --> 00:05:18.480 what was already suspected or known in isolation. The total 111 00:05:18.519 --> 00:05:21.720 count of these small mirror ridges across the Moon jumps 112 00:05:21.759 --> 00:05:23.839 to two thousand, six hundred thirty four. 113 00:05:23.720 --> 00:05:27.000 Two thousand, six hundred. That is a significant amount of wrinkling. 114 00:05:27.040 --> 00:05:29.240 That's not just a localized anomaly, that's a pattern. 115 00:05:29.360 --> 00:05:32.839 It completely changes the map. It strongly suggests a global 116 00:05:32.879 --> 00:05:33.879 process is at work. 117 00:05:34.000 --> 00:05:35.399 I have to pause on that for a second, though. 118 00:05:35.439 --> 00:05:38.879 I mean, we've been staring at the Moon with high 119 00:05:38.959 --> 00:05:44.839 powered telescopes for centuries. We've sent orbiters, we've literally had 120 00:05:44.879 --> 00:05:48.040 boots on the ground. Apollo astronauts walked on the mirror. 121 00:05:48.279 --> 00:05:50.839 How on earth did we miss over a thousand of 122 00:05:50.879 --> 00:05:51.600 these ridges. 123 00:05:51.680 --> 00:05:56.079 It's a combination of a few things, resolution, lighting, and frankly, attention. 124 00:05:56.720 --> 00:05:58.959 We knew about similar ridges in the Highlands. We'll get 125 00:05:59.000 --> 00:06:01.959 to those later. They're called obate scarps, right, But the 126 00:06:02.000 --> 00:06:06.199 prevailing assumption was that the Maria, those deep, thick lava 127 00:06:06.240 --> 00:06:11.800 planes were structurally different, maybe thicker, more stable, less prone 128 00:06:11.800 --> 00:06:12.399 to breaking. 129 00:06:12.759 --> 00:06:14.199 So we weren't really looking for them there. 130 00:06:14.240 --> 00:06:16.600 We weren't looking for them on this scale. Finding them 131 00:06:16.639 --> 00:06:20.000 widespread in the Maria is the game changer. Cole Nipe, 132 00:06:20.360 --> 00:06:23.120 the lead author, he emphasized this. He noted that this 133 00:06:23.199 --> 00:06:26.759 is the first time scientists have documented the widespread prevalence 134 00:06:26.800 --> 00:06:28.800 of these features throughout the lunar mare. 135 00:06:29.000 --> 00:06:30.800 So it's not that they were invisible and so we 136 00:06:30.800 --> 00:06:33.560 didn't realize they were everywhere, that it was a consistent pattern. 137 00:06:33.639 --> 00:06:36.399 Precisely. It's like looking at a smooth sheet of ice 138 00:06:36.439 --> 00:06:39.319 on a lake from a distance, it looks perfect. But 139 00:06:39.319 --> 00:06:41.160 if you get down on your hands and knees with 140 00:06:41.199 --> 00:06:43.600 a magnifying glass, or if you catch the light just 141 00:06:43.680 --> 00:06:44.959 right at sunset. 142 00:06:44.639 --> 00:06:45.480 Ah the lighting. 143 00:06:45.560 --> 00:06:49.240 The lighting is key. Low angle sunlight makes shadows that 144 00:06:49.279 --> 00:06:53.279 reveal subtle topography. You suddenly realize the whole sheet of 145 00:06:53.319 --> 00:06:57.639 ice is crisscrossed with tiny stress fractures and ridges. 146 00:06:57.600 --> 00:07:00.519 And those fractures tell you the ice is under pressure exactly. 147 00:07:00.600 --> 00:07:03.240 They tell you the ice is moving or changing shape, 148 00:07:03.240 --> 00:07:05.480 that it's not as stable as it looks, which. 149 00:07:05.360 --> 00:07:08.519 Leads us perfectly to the mechanism the why we have 150 00:07:08.519 --> 00:07:11.319 two six hundred and thirty four of these ridges. The 151 00:07:11.319 --> 00:07:14.680 moon is wrinkling, So why I thought the moon was 152 00:07:14.720 --> 00:07:16.319 a solid, frozen block of stone, And. 153 00:07:16.399 --> 00:07:19.319 Understand the why we have to do a little comparative planetology. 154 00:07:19.319 --> 00:07:21.199 It really helps to look at Earth versus the Moon. 155 00:07:21.240 --> 00:07:23.399 Okay, Earth versus Moon ding. 156 00:07:23.360 --> 00:07:27.319 Ding fight chuckles, It's less of a fight and more 157 00:07:27.319 --> 00:07:31.079 of a contrast in styles. Earth is driven by plate tectonics. 158 00:07:31.160 --> 00:07:33.360 We all learned about this in school. Our crust is 159 00:07:33.399 --> 00:07:36.519 broken into these massive puzzle pieces, the tectonic. 160 00:07:36.040 --> 00:07:39.319 Plates, right, the North American plate, Pacific plate, and so on. 161 00:07:39.600 --> 00:07:43.920 And they float on the semi molten mantle. They crash 162 00:07:43.959 --> 00:07:46.519 into each other to create the Himalayas, they pull apart 163 00:07:46.519 --> 00:07:49.600 to create the Atlantic Ocean. They slide past each other 164 00:07:49.800 --> 00:07:53.800 to create the San Andrea's fault. It's a chaotic, multi. 165 00:07:53.600 --> 00:07:55.360 Piece system, very dynamic. 166 00:07:55.480 --> 00:07:59.560 Everything is constantly moving and recycling. It's a very active surface. 167 00:07:59.399 --> 00:08:02.920 Right, dynamic puzzle where the pieces are always shuffling around. 168 00:08:03.000 --> 00:08:05.319 The Moon is different. The Moon is what we call 169 00:08:05.360 --> 00:08:06.800 a one plate body. 170 00:08:06.959 --> 00:08:09.759 One plate, so it's just a continuous solid shell. 171 00:08:09.959 --> 00:08:13.120 It's a single solid lithosphere. There are no other plates 172 00:08:13.120 --> 00:08:15.800 to crash into. It's like an orange peel that hasn't 173 00:08:15.800 --> 00:08:18.480 been sectioned yet, just one solid piece. 174 00:08:18.639 --> 00:08:21.439 So if there are no plates colliding, how do you 175 00:08:21.480 --> 00:08:24.120 get a ridge? How do you get a mountain? Usually 176 00:08:24.120 --> 00:08:26.800 a mountain is formed when two things smash together, right, Yeah, 177 00:08:27.079 --> 00:08:29.360 like cars in a head on collision. The hoods just 178 00:08:29.439 --> 00:08:29.959 buckle up. 179 00:08:30.040 --> 00:08:33.919 On Earth, yes, that's the primary mountain building process. But 180 00:08:34.120 --> 00:08:36.600 on the Moon, the ridges are formed because the Moon is. 181 00:08:36.519 --> 00:08:39.240 Shrinking, shrinking, It is getting physically smaller. 182 00:08:39.279 --> 00:08:41.799 The whole thing, the whole thing is contracting. Yes, its 183 00:08:41.879 --> 00:08:45.120 radius is slowly but measurably decreasing. 184 00:08:45.440 --> 00:08:49.919 Okay, help me with the physics here. It is it evaporating, 185 00:08:50.039 --> 00:08:52.159 Is it leaking mass into space or something. 186 00:08:52.440 --> 00:08:55.960 It's a much simpler process. Actually, it's thermal contraction. You 187 00:08:56.039 --> 00:09:00.279 have to remember the Moon was born in incredible violenceaing 188 00:09:00.320 --> 00:09:03.720 theory is the giant impact hypothesis, the big whack, the 189 00:09:03.720 --> 00:09:07.639 big whack, exactly, a Mars sized object smashed into the 190 00:09:07.679 --> 00:09:11.360 early Earth, and the debris from that collision eventually coalesced 191 00:09:11.440 --> 00:09:12.279 to form the Moon. 192 00:09:12.639 --> 00:09:14.360 So it started out hot, very hot. 193 00:09:14.480 --> 00:09:18.440 It started out molten a global magma ocean, and for 194 00:09:18.519 --> 00:09:21.960 the last four point five billion years it has been 195 00:09:22.000 --> 00:09:25.279 slowly radiating all that primordial heat out into the cold 196 00:09:25.360 --> 00:09:28.080 vacuum of space. It's cooling down, it's cooling down and 197 00:09:28.159 --> 00:09:30.440 as we know from basic physics, when most things cool down, 198 00:09:30.480 --> 00:09:33.480 they contract, they lose volume, and the atoms and molecules 199 00:09:33.480 --> 00:09:34.279 get closer together. 200 00:09:34.399 --> 00:09:37.000 So the hot interior is cooling and shriveling up like 201 00:09:37.039 --> 00:09:38.120 a balloon losing air. 202 00:09:38.279 --> 00:09:39.879 That's a good way to put it. But the crust, 203 00:09:39.919 --> 00:09:43.240 the outer shell, is hard rock. It's brittle. It cooled 204 00:09:43.320 --> 00:09:46.200 and hardened a long long time ago. So now you 205 00:09:46.240 --> 00:09:49.480 have this shrinking interior pulling away from a rigid crust 206 00:09:49.679 --> 00:09:51.679 that is already set in its size. 207 00:09:51.960 --> 00:09:53.840 So the shell is suddenly too big for the body 208 00:09:53.919 --> 00:09:54.399 inside it. 209 00:09:54.519 --> 00:09:56.960 That's a perfect description. I think the best analogy is 210 00:09:57.000 --> 00:09:59.799 the grape turning into a raisin. I was just thinking 211 00:09:59.799 --> 00:10:03.000 that as the pulp inside the grape dries out and shrinks, 212 00:10:03.360 --> 00:10:06.240 the skin suddenly has way too much surface area. It 213 00:10:06.240 --> 00:10:09.200 has to go somewhere. It can't dissolve, it can't just disappear. 214 00:10:09.440 --> 00:10:12.279 So what does it do. It buckles, It folds over 215 00:10:12.399 --> 00:10:14.679 on itself to take up the extra space. 216 00:10:14.519 --> 00:10:17.240 And that folds that's the ridge, that is the ridge. 217 00:10:17.480 --> 00:10:20.919 In geology we call this a thrust fault. The crust 218 00:10:21.000 --> 00:10:24.600 is being put under immense global compression. It's being squeezed 219 00:10:24.600 --> 00:10:29.000 from all sides until the rock literally snaps. One section 220 00:10:29.039 --> 00:10:31.399 of the ground is thrust up and over the adjacent 221 00:10:31.440 --> 00:10:34.279 section to accommodate the smaller surface area. 222 00:10:34.440 --> 00:10:37.200 That is such a powerful image. The Moon is literally 223 00:10:37.240 --> 00:10:40.000 crushing its own surface because it's imploding in slow motion. 224 00:10:40.480 --> 00:10:42.919 Imploding might be a bit dramatic for the timescale, but 225 00:10:43.080 --> 00:10:46.279 contracting is stot on. It is a global squeeze and 226 00:10:46.320 --> 00:10:49.799 the numbers are pretty impressive. Scientists estimate the Moon has 227 00:10:49.840 --> 00:10:52.960 shrunk by about one hundred and fifty feet roughly fifty 228 00:10:53.039 --> 00:10:56.039 meters in radius over the last several hundred million years. 229 00:10:56.480 --> 00:10:59.000 One hundred and fifty feet. You know, that doesn't sound 230 00:10:59.039 --> 00:11:00.320 like a lot for a body of this size of 231 00:11:00.360 --> 00:11:00.679 the Moon. 232 00:11:00.960 --> 00:11:03.480 It sounds small, But think about the energy required to 233 00:11:03.519 --> 00:11:07.240 compress a solid ball of rock that's over two thousand 234 00:11:07.279 --> 00:11:10.440 miles in diameter by one hundred and fifty feet. That 235 00:11:10.559 --> 00:11:13.399 is a tremendous amount of stored stress energy that has 236 00:11:13.440 --> 00:11:16.960 to be released, and it releases it by breaking the rock. 237 00:11:17.039 --> 00:11:20.840 Which creates these faults. Now, the study makes a distinction 238 00:11:20.919 --> 00:11:24.120 here that I want to clarify. We're talking about smr's 239 00:11:24.320 --> 00:11:27.519 small mare ridges, But you mentioned earlier that we already 240 00:11:27.559 --> 00:11:30.799 knew about ridges in the highlands. The study calls those 241 00:11:31.279 --> 00:11:34.440 low bait scarps. Is there a real difference or is 242 00:11:34.480 --> 00:11:37.600 this just scientists loving different names for the same thing. 243 00:11:37.919 --> 00:11:41.039 It's a great question. It's a distinction in geography mostly, 244 00:11:41.159 --> 00:11:43.159 but not really in mechanism. 245 00:11:43.320 --> 00:11:44.080 Break that down for me. 246 00:11:44.279 --> 00:11:46.360 So, low bate scarps are found in the highlands, the 247 00:11:46.399 --> 00:11:49.799 ancient rocky mountainous terrain. We've known about those since the 248 00:11:49.840 --> 00:11:52.399 Apollo missions. We've seen them, we've mapped them. They look 249 00:11:52.480 --> 00:11:54.960 like big stair steps or cliffs in the landscape. 250 00:11:55.039 --> 00:11:56.720 Okay, so they're the highland version. 251 00:11:56.679 --> 00:11:59.519 Exactly, and SMRs are essentially the same type of feature. 252 00:11:59.559 --> 00:12:02.039 They're just in the Maria the basalt lava planes. 253 00:12:02.320 --> 00:12:04.519 Okay, so it's just about where they are located. It's 254 00:12:04.519 --> 00:12:06.720 like calling a sandwich a sub in one city and 255 00:12:06.799 --> 00:12:09.000 a hoogee in another. It's the same thing. 256 00:12:09.120 --> 00:12:11.639 That's a fair analogy, and the key finding from this 257 00:12:11.720 --> 00:12:15.000 analysis by Nipeverr and Waters is that it confirms they 258 00:12:15.000 --> 00:12:17.759 are formed by the exact same type of faults. They 259 00:12:17.759 --> 00:12:20.159 are both thrust falls. They are caused by the exact 260 00:12:20.159 --> 00:12:22.200 same global contractional forces. 261 00:12:22.279 --> 00:12:25.480 It's the same squeeze just happening in different types of rock. 262 00:12:25.840 --> 00:12:28.879 It is, and here is the smoking gun, the real clincher. 263 00:12:29.559 --> 00:12:32.159 The study found instances where a low bit scarp in 264 00:12:32.159 --> 00:12:35.360 the mountains travels down a slope, hits the flat mare, 265 00:12:35.600 --> 00:12:38.039 and transitions directly into an smr. 266 00:12:38.240 --> 00:12:41.519 Oh wow. So it's one continuous crack running from the 267 00:12:41.559 --> 00:12:43.000 mountains right into the sea. 268 00:12:42.840 --> 00:12:45.759 So to speak, exactly, it's a single fault system that 269 00:12:45.879 --> 00:12:49.919 completely ignores the terrain boundary. And this is powerful evidence 270 00:12:49.919 --> 00:12:53.240 because it confirms that the shrinking isn't localized. It's not 271 00:12:53.399 --> 00:12:56.320 just something happening in the old mountains. It's a global contraction. 272 00:12:56.840 --> 00:12:58.919 The entire Moon is tightening its belt. 273 00:12:59.080 --> 00:13:02.799 That answers the and the why. But I really want 274 00:13:02.840 --> 00:13:05.440 to talk about the when, because you know, recent in 275 00:13:05.559 --> 00:13:09.360 geology usually means like a billion years ago. Scientists have 276 00:13:09.399 --> 00:13:12.240 a totally warped sense of time compared to the rest 277 00:13:12.279 --> 00:13:14.679 of us. How fresh are these wrinkles? 278 00:13:14.879 --> 00:13:16.519 This is one of the most exciting parts of the 279 00:13:16.559 --> 00:13:18.159 study for me. The dating. 280 00:13:18.720 --> 00:13:20.559 Okay, so how do you date a wrinkle on the 281 00:13:20.559 --> 00:13:23.519 Moon without actually landing on it and taking a rock sample. 282 00:13:24.240 --> 00:13:26.759 We don't have carbon dating for rocks from orbit. 283 00:13:27.200 --> 00:13:30.320 No, we don't. We use a clever technique called crater counting. 284 00:13:30.360 --> 00:13:33.399 It's one of the most fundamental tools in planetary science. 285 00:13:33.600 --> 00:13:35.240 Right, walk us through that logic. 286 00:13:35.399 --> 00:13:39.279 It's based on probability and a classic geological principle, the 287 00:13:39.399 --> 00:13:43.600 law of superposition. The Moon, like anybody in the Solar System, 288 00:13:43.679 --> 00:13:47.480 is constantly being bombarded by meteoroids, big ones, small ones, 289 00:13:47.600 --> 00:13:52.240 tiny micromedioroids, over billions of years. Surfaces accumulate craters like 290 00:13:52.279 --> 00:13:54.000 a sidewalk accumulates gum. 291 00:13:54.159 --> 00:13:56.279 Gross but a very effective image. 292 00:13:56.440 --> 00:13:59.960 A very old surface like the Highlands will be absolutely 293 00:14:00.120 --> 00:14:03.480 covered in craters. It's saturated. You can't make a new 294 00:14:03.519 --> 00:14:06.600 crater without destroying an old one. A brand new surface, 295 00:14:06.679 --> 00:14:10.600 like a fresh lava flow, will be smooth and almost pristine. 296 00:14:10.799 --> 00:14:13.360 Okay, more plock marks equals older skin. 297 00:14:14.000 --> 00:14:17.000 That makes sense exactly. Now. You look at the relationship 298 00:14:17.039 --> 00:14:20.159 between the ridge and the craters around it. If you 299 00:14:20.240 --> 00:14:23.000 have a ridge an smr and it cuts through a 300 00:14:23.000 --> 00:14:26.799 small crater, distorting it or breaking it in half, what 301 00:14:26.879 --> 00:14:27.519 does that tell you? 302 00:14:27.639 --> 00:14:29.440 It tells you the ridge formed after the crater. 303 00:14:29.600 --> 00:14:33.000 The ridge is younger, precisely. But if there are tiny, 304 00:14:33.120 --> 00:14:35.240 fresh looking craters sitting on top of the ridge and 305 00:14:35.279 --> 00:14:38.159 they are undisturbed, perfectly round little bowls, then the ridge 306 00:14:38.240 --> 00:14:40.200 must have formed before those craters hit. 307 00:14:40.600 --> 00:14:43.279 It's a game of geological layering who is on top 308 00:14:43.320 --> 00:14:44.240 of whom it is. 309 00:14:44.600 --> 00:14:47.559 And by carefully counting the density and size of craters 310 00:14:47.600 --> 00:14:50.360 on and around these ridges and plugging that into models 311 00:14:50.360 --> 00:14:53.080 of how often craters of a certain sized form, the 312 00:14:53.120 --> 00:14:56.039 team was able to calculate an average model age and 313 00:14:56.080 --> 00:14:58.519 the numbers are Ah, they're shocking. 314 00:14:58.600 --> 00:14:59.759 Okay, hit me with the numbers. 315 00:15:00.000 --> 00:15:02.559 The average age of these small marre ridges is roughly 316 00:15:02.600 --> 00:15:05.559 one hundred and twenty four million years one hundred twenty 317 00:15:05.600 --> 00:15:08.559 four million and for comparison, the low bit scarps in 318 00:15:08.600 --> 00:15:11.559 the Highlands, which Tom Waters had previously analyzed, have a 319 00:15:11.559 --> 00:15:14.360 similar average age of about one hundred and five million years. 320 00:15:14.480 --> 00:15:17.639 Okay, I need you to contextualize this for me. To me, 321 00:15:18.279 --> 00:15:21.600 a human who hopes to live to maybe ninety one 322 00:15:21.639 --> 00:15:26.679 hundred and twenty four million years sounds incredibly ancient. That's 323 00:15:26.720 --> 00:15:29.399 the Cretaceous period on Earth, dinosaurs were walking around. 324 00:15:29.480 --> 00:15:31.720 It feels like an eternity to us. But you have 325 00:15:31.759 --> 00:15:35.440 to shift your perspective to geological time to cosmic time. 326 00:15:35.840 --> 00:15:38.279 The Moon is about four point five billion. 327 00:15:38.000 --> 00:15:40.840 Years old, right, so forty five hundred million years exactly. 328 00:15:41.080 --> 00:15:43.399 So if you imagine the Moon's entire life as a 329 00:15:43.440 --> 00:15:46.240 twenty four hour clock from its formation at midnight to 330 00:15:46.279 --> 00:15:48.879 the present day, one hundred million years is the last 331 00:15:48.879 --> 00:15:51.440 half hour, maybe even less. It's the last few minutes 332 00:15:51.480 --> 00:15:52.440 before the clock strikes. 333 00:15:52.440 --> 00:15:54.960 Now, Oh wow, Okay, that puts it in perspective. 334 00:15:55.080 --> 00:15:57.759 These features represent the last what two or three percent 335 00:15:57.759 --> 00:16:00.679 of the Moon's entire history in geological time. These are 336 00:16:00.720 --> 00:16:03.759 fresh wounds. They are very likely the youngest tectonic features 337 00:16:03.759 --> 00:16:04.919 on the entire lunar body. 338 00:16:05.159 --> 00:16:07.320 So when we look at the Moon, we aren't just 339 00:16:07.399 --> 00:16:11.320 seeing ancient scars from its violent birth. We aren't just 340 00:16:11.360 --> 00:16:14.720 seeing the bombardment from the early Solar system. We are 341 00:16:14.759 --> 00:16:19.399 seeing things that happened well yesterday in space terms. 342 00:16:19.559 --> 00:16:22.720 And the really big implication of that youth is that 343 00:16:22.759 --> 00:16:25.519 the process is likely still forming them. 344 00:16:25.679 --> 00:16:28.240 That's the kicker, isn't it. An average age of one 345 00:16:28.279 --> 00:16:30.759 hundred million years doesn't mean they all formed and then 346 00:16:30.799 --> 00:16:34.360 stopped one hundred million years ago. It means the process 347 00:16:34.399 --> 00:16:37.039 that made them has been active in the very recent 348 00:16:37.080 --> 00:16:40.039 past and is in all probability ongoing. 349 00:16:40.320 --> 00:16:43.480 The Moon is still cooling, we know that from thermal models. Therefore, 350 00:16:43.480 --> 00:16:46.200 it is still shrinking. Therefore, the stress is still building 351 00:16:46.279 --> 00:16:48.840 up in the crust. Therefore the crust is still cracking. 352 00:16:48.600 --> 00:16:50.679 Right, which brings us to the part of the conversation 353 00:16:50.720 --> 00:16:53.200 that sounds a bit like a disaster movie. If the 354 00:16:53.240 --> 00:16:56.720 crust is snapping to make these ridges, that snap must 355 00:16:56.759 --> 00:16:58.919 release a lot of energy. When rock breaks under that 356 00:16:59.000 --> 00:17:01.039 much pressure, it's not quiet. 357 00:17:01.120 --> 00:17:02.440 It creates seismic activity. 358 00:17:02.519 --> 00:17:03.679 Moonquakes, moonquakes. 359 00:17:03.720 --> 00:17:04.319 Absolutely. 360 00:17:04.359 --> 00:17:06.599 We've all heard of earthquakes. We know about the devastation 361 00:17:06.680 --> 00:17:11.920 they can cause here. But moonquakes are a real, documented phenomena. 362 00:17:12.240 --> 00:17:16.400 Oh, they are very real. The Apollo astronauts actually placed 363 00:17:16.759 --> 00:17:21.680 seismometers on the lunar surface Apollo eleven, twelve, fourteen, fifteen, 364 00:17:21.720 --> 00:17:26.519 and sixteen all left working instruments behind. They formed a network. 365 00:17:26.759 --> 00:17:28.519 I remember seeing pictures of those. 366 00:17:28.480 --> 00:17:31.759 And they recorded thousands of seismic events between nineteen sixty 367 00:17:31.839 --> 00:17:34.119 nine and nineteen seventy seven when they were finally turned 368 00:17:34.160 --> 00:17:35.000 off to save money. 369 00:17:35.240 --> 00:17:39.000 And this new study connects those recorded quakes to these ridges. 370 00:17:39.240 --> 00:17:42.839 It solidifies the connection yes, there are different types of moonquakes. 371 00:17:42.880 --> 00:17:45.240 Some are very deep caused by the tidal pull of 372 00:17:45.319 --> 00:17:48.480 Earth's gravity. But the shallow ones, the ones that happen 373 00:17:48.480 --> 00:17:50.759 in the upper crust, those are the dangerous ones. 374 00:17:50.799 --> 00:17:52.039 And those are the tectonic ones. 375 00:17:52.079 --> 00:17:54.440 Those are the tectonic ones. And Tom Waters, one of 376 00:17:54.440 --> 00:17:57.039 the authors of this new study had previously done work 377 00:17:57.039 --> 00:17:59.400 that linked the low bait scarps in the Highlands to 378 00:17:59.440 --> 00:18:03.079 some of the wrongest shallow moonquakes recorded by the Apollo network. 379 00:18:03.359 --> 00:18:06.200 He basically triangulated the epicenters of the quakes to these 380 00:18:06.279 --> 00:18:07.039 known faults. 381 00:18:07.119 --> 00:18:09.759 Okay, so we knew the highland scarps were seismically active, 382 00:18:10.200 --> 00:18:11.400 but now we have this new map. 383 00:18:11.599 --> 00:18:15.559 Now we have eleven and fourteen new ridges cataloged in 384 00:18:15.559 --> 00:18:17.880 the Maria, which we now know are the same type 385 00:18:17.920 --> 00:18:18.359 of feature. 386 00:18:18.680 --> 00:18:20.440 So the safe zone isn't safe. 387 00:18:20.759 --> 00:18:23.839 That is the critical takeaway. Previously, mission planners looked at 388 00:18:23.880 --> 00:18:27.599 the Marie and thought perfect flat stable, easy to land on, 389 00:18:28.079 --> 00:18:31.440 no cliffs a crash into, no mountains to navigate. But 390 00:18:31.559 --> 00:18:34.759 now we know that SMRs are widespread there and they 391 00:18:34.799 --> 00:18:37.920 are formed by the exact same mechanism that causes powerful 392 00:18:38.000 --> 00:18:39.240 quakes in the Highlands. 393 00:18:39.519 --> 00:18:42.880 So basically, anywhere there is a wrinkle on this new map, 394 00:18:43.279 --> 00:18:46.160 there is a potential epicenter for a future meanquake. 395 00:18:46.319 --> 00:18:49.200 That's right, any place with an SMR has to be 396 00:18:49.240 --> 00:18:52.640 considered a potential source of shallow seismic activity, and we 397 00:18:52.759 --> 00:18:55.039 just found out they are all over the place, including 398 00:18:55.160 --> 00:18:57.519 many of the areas considered prime landing spots. 399 00:18:57.799 --> 00:19:00.160 This really complicates things for the Artemis program. 400 00:19:00.240 --> 00:19:02.640 It complicates things for anyone planning to stay on the 401 00:19:02.680 --> 00:19:05.039