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 --> 00:00:23.800 slumber under the night sky. 7 00:00:27.000 --> 00:00:31.839 So imagine you are standing on a shoreline. But this 8 00:00:31.879 --> 00:00:35.560 isn't anywhere on Earth. The atmospheric pressure pressing against your 9 00:00:35.600 --> 00:00:38.920 suit is noticeably heavier, right, It's about fifty percent thicker 10 00:00:38.920 --> 00:00:39.719 than what you're used to. 11 00:00:40.039 --> 00:00:41.479 Yeah, it would feel a bit like being at the 12 00:00:41.520 --> 00:00:44.479 bottom of a shallow pool, just from the air pressure alone. 13 00:00:44.600 --> 00:00:47.960 Right, But at the exact same time, you feel almost weightless, 14 00:00:48.560 --> 00:00:52.640 And then a breeze brushes past you. It's barely a zephyr. 15 00:00:52.679 --> 00:00:55.119 I mean, maybe two or three miles per. 16 00:00:54.960 --> 00:00:58.399 Hour, which is nothing on a beach here on Earth. 17 00:00:58.560 --> 00:01:02.399 A wind bit light wouldn't even disrupt the surface tension 18 00:01:02.439 --> 00:01:04.439 of a tiny tide pool. You wouldn't even see. 19 00:01:04.319 --> 00:01:06.879 A ripple exactly. But as you look out at the 20 00:01:06.879 --> 00:01:09.319 liquid expanse in front of you, the physics just totally 21 00:01:09.400 --> 00:01:12.640 break down. You are watching these massive ten foot tall 22 00:01:12.840 --> 00:01:16.719 swells rolling toward the shore, and because of the gravitational 23 00:01:16.760 --> 00:01:20.280 mechanics at play, they're crashing in this like haunting, drawn 24 00:01:20.319 --> 00:01:23.519 out slow motions. Such an incredible visual, it really is, 25 00:01:23.920 --> 00:01:26.480 And you are standing on the shores of kraken Mare. 26 00:01:26.599 --> 00:01:29.599 It's the largest liquid body on Titan, which is Saturn's 27 00:01:29.680 --> 00:01:33.000 largest moon. And we're not just making up a sci 28 00:01:33.000 --> 00:01:37.840 fi scenario here. This specific visual is actually the mathematical 29 00:01:37.959 --> 00:01:41.680 key to solving one of the most perplexing planetary mysteries 30 00:01:41.719 --> 00:01:43.159 in our entire Solar system. 31 00:01:43.280 --> 00:01:46.319 It really is. It forces a complete recalibration of our 32 00:01:46.359 --> 00:01:49.920 intuitive understanding of fluid dynamics. I mean, we've had radar 33 00:01:49.959 --> 00:01:53.040 imagery of Titan from the Cassini mission for years now. 34 00:01:52.920 --> 00:01:55.879 Right, Yeah, mapping out all those crazy liquid networks exactly. 35 00:01:55.920 --> 00:02:00.560 We've mapped these vast, branching river networks that physically carved 36 00:02:00.640 --> 00:02:03.079 through the icy bedrock and they just empty out into 37 00:02:03.120 --> 00:02:05.879 these mats of lakes of liquid methane and ethane. But 38 00:02:05.959 --> 00:02:09.560 here's the thing. Geologically speaking, when you have mature river 39 00:02:09.639 --> 00:02:12.919 networks feeding into a standing body of liquid, you expect 40 00:02:12.919 --> 00:02:14.400 to see deltas right like. 41 00:02:14.360 --> 00:02:16.840 The Mississippi Delta of the Nile. You expect a bunch 42 00:02:16.879 --> 00:02:19.560 of mud and sand to just pile up exactly. 43 00:02:19.719 --> 00:02:23.319 You expect to find massive alluvial fans of sediment deposited 44 00:02:23.439 --> 00:02:26.280 right at the mouths of those rivers. Yeah, but on Titan, 45 00:02:26.479 --> 00:02:29.240 the deltas are virtually non existent. The rivers just hit 46 00:02:29.319 --> 00:02:32.759 the coastline and stop. It's a glaring anomaly, and that. 47 00:02:32.680 --> 00:02:34.639 Anomaly brings us to what we're going to deep dig 48 00:02:34.680 --> 00:02:37.800 into today. We're looking at a brand new framework developed 49 00:02:37.840 --> 00:02:41.840 by researchers at the Massachusetts Institute of Technology, specifically in 50 00:02:41.879 --> 00:02:45.120 their Department of Earth, Atmospheric and Planetary Sciences. 51 00:02:45.439 --> 00:02:45.639 Yeah. 52 00:02:45.719 --> 00:02:49.560 Lead author Unashneck and Taylor Puran, they really cracked this open. 53 00:02:49.759 --> 00:02:53.240 They did. They published this model called Planet Waves in 54 00:02:53.280 --> 00:02:57.400 the Journal of Geophysical Research Planets. And what's wild is 55 00:02:57.680 --> 00:02:59.759 they didn't set out to build some like sci fi 56 00:02:59.759 --> 00:03:03.439 Wina simulator for fun. They built a rigorous mathematical tool 57 00:03:03.639 --> 00:03:08.360 to solve this exact geological discrepancy on Titan and honestly, 58 00:03:08.400 --> 00:03:11.919 by extension, any planetary body with liquid. 59 00:03:11.680 --> 00:03:15.680 Because waves are the engines of coastal erosion. The MIT 60 00:03:15.840 --> 00:03:20.039 team basically hypothesized that if Titan's coastal environments were volatile enough, 61 00:03:20.080 --> 00:03:23.599 the wave action would essentially act as a giant planetary sander. 62 00:03:23.800 --> 00:03:27.360 It would relentlessly obliterate any sediment deposits before delta could 63 00:03:27.360 --> 00:03:28.080 ever even form. 64 00:03:28.400 --> 00:03:31.919 Wow, so just wiping the slate clean constantly, exactly. 65 00:03:32.560 --> 00:03:35.120 But to prove that, they had to understand exactly how 66 00:03:35.120 --> 00:03:38.879 waves are generated in an environment that shares almost none 67 00:03:38.960 --> 00:03:41.039 of Earth's baseline. 68 00:03:40.479 --> 00:03:45.520 Variables, right, because previous attempts to model alien oceans usually 69 00:03:45.560 --> 00:03:48.120 just stopped at the most obvious variable, which is gravity. 70 00:03:48.199 --> 00:03:50.360 Yeah, gravity is the simplest calculation, and. 71 00:03:50.360 --> 00:03:53.759 Titan has roughly one seventh the gravitational pull of Earth. 72 00:03:54.080 --> 00:03:58.199 So less gravity means less downward force on the liquid, 73 00:03:58.240 --> 00:04:01.439 which means the liquid is easy to lift. But when 74 00:04:01.479 --> 00:04:05.159 I was looking at this, that single variable analysis completely 75 00:04:05.199 --> 00:04:07.520 falls apart when you actually look at momentum transfer. Right. 76 00:04:07.599 --> 00:04:11.120 Oh, absolutely yeah. If gravity was the only variable that mattered, 77 00:04:11.599 --> 00:04:15.080 a high pressure atmosphere moving across a low gravity liquid 78 00:04:15.599 --> 00:04:18.040 should theoretically just shear the surface right off. 79 00:04:18.079 --> 00:04:20.240 It would atomize it, like, just turn the whole lake 80 00:04:20.240 --> 00:04:20.920 into a miss. 81 00:04:21.000 --> 00:04:23.439 Right, So the model had to account for the liquid's 82 00:04:23.439 --> 00:04:25.800 actual composition, and that is. 83 00:04:25.720 --> 00:04:29.519 The huge critical advancement of the Planet Waves model. It 84 00:04:29.720 --> 00:04:36.000 isolates and calculates this intricate dance between gravitational acceleration, atmospheric pressure, 85 00:04:36.439 --> 00:04:39.639 and the specific the reology of the liquid. 86 00:04:39.399 --> 00:04:42.800 Its density, its kinematic viscosity, and its surface tension. 87 00:04:43.360 --> 00:04:47.319 Right and Andrew Ashton, a researcher at the Woodshole Oceanographic 88 00:04:47.360 --> 00:04:50.920 Institution who collaborated on this. He framed the core math 89 00:04:51.040 --> 00:04:54.240 challenge around predicting what he calls the first puff. 90 00:04:54.360 --> 00:04:55.800 I love that phrase, the first puff. 91 00:04:55.879 --> 00:04:59.920 It's so descriptive. You have a completely quiescent, glassy liquid surface. 92 00:05:00.439 --> 00:05:03.720 The model has to calculate the exact threshold of atmospheric 93 00:05:03.759 --> 00:05:07.839 kinetic energy required to overcome the liquid's internal cohesive forces 94 00:05:08.319 --> 00:05:11.839 and generate a capillary wave, just a tiny ripple, because. 95 00:05:11.639 --> 00:05:14.920 Once that boundary layer is broken, the physics change entirely. 96 00:05:15.000 --> 00:05:17.360 Tell me about that, because this transition is fascinating. 97 00:05:17.399 --> 00:05:20.680 Well, once you get that first ripple, you introduce aerodynamic drag. 98 00:05:21.240 --> 00:05:23.920 The wind starts catching the windward side of that ripple 99 00:05:23.959 --> 00:05:26.480 and then compounds the energy transfer, so it turns a 100 00:05:26.560 --> 00:05:30.480 tiny capillary wave into a full scale gravity wave. 101 00:05:30.519 --> 00:05:34.000 So the surface roughness increases, which basically allows the wind 102 00:05:34.000 --> 00:05:35.759 to get a grip on the liquid. 103 00:05:35.480 --> 00:05:39.319 Exactly the wind grips the water. But modeling that transition 104 00:05:39.439 --> 00:05:43.519 from a perfectly flat plane to a chaotic turbulent swell 105 00:05:43.720 --> 00:05:48.759 that requires a flawless understanding of energy transfer coefficients. You 106 00:05:48.759 --> 00:05:51.079 can't just plug in the density of liquid methane and 107 00:05:51.120 --> 00:05:51.839 hope for the best. 108 00:05:52.040 --> 00:05:54.439 No, you have to calibrate the math against a known, 109 00:05:54.680 --> 00:05:56.639 highly erratic system first. 110 00:05:56.480 --> 00:05:59.920 Right, which is why the MIT team didn't start with Titan. 111 00:06:00.000 --> 00:06:03.439 Started in our own backyard. They validated the planet waves 112 00:06:03.480 --> 00:06:08.160 model using twenty years of continuous meteorological and oceanographic data 113 00:06:08.160 --> 00:06:09.680 from Lake Superior, which. 114 00:06:09.439 --> 00:06:12.839 Is perfect because geologically speaking, Lake Superior operates as an 115 00:06:12.839 --> 00:06:13.680 inland ocean. 116 00:06:13.800 --> 00:06:17.639 Yeah, it's massive. It has these huge fetch lengths, violent squalls, 117 00:06:17.680 --> 00:06:20.560 and then prolonged periods of absolute dead calm. 118 00:06:20.480 --> 00:06:23.040 And the National Data Boyse Center maintains a rays all 119 00:06:23.079 --> 00:06:28.319 across Lake Superior. They provide high frequency sampling of wave period, amplitude, 120 00:06:28.720 --> 00:06:30.480 wind sheer, stress, all of. 121 00:06:30.439 --> 00:06:33.519 It, and having twenty years of that data allows researchers 122 00:06:33.560 --> 00:06:36.720 to filter out all the statistical noise, right like roague 123 00:06:36.720 --> 00:06:39.040 currents or localized thermal inversions. 124 00:06:38.680 --> 00:06:43.120 Exactly atmosphere canomalies, all the weird outliers. They fed the 125 00:06:43.160 --> 00:06:46.839 Planet Waves model the historical wind velocity and atmosphere of 126 00:06:46.839 --> 00:06:50.560 pressure for specific days. They locked in Earth's gravity and 127 00:06:50.600 --> 00:06:54.120 the density of fresh water, and then basically said, okay, 128 00:06:54.160 --> 00:06:58.120 model predict the wave height and frequency for this civic 129 00:06:58.199 --> 00:06:59.759 Tuesday in two thousand and eight. 130 00:07:00.160 --> 00:07:04.639 And it worked flawlessly. The model matched the buoy data perfectly. 131 00:07:05.079 --> 00:07:08.600 It accurately predicted the exact wind shear required to initiate 132 00:07:08.639 --> 00:07:11.399 those capillary waves and the subsequent growth into full scale 133 00:07:11.439 --> 00:07:12.199 gravity waves. 134 00:07:12.319 --> 00:07:14.560 It's an incredible proof of concept, it really is. 135 00:07:14.839 --> 00:07:17.160 But this is where the concept of viscosity becomes the 136 00:07:17.199 --> 00:07:19.839 absolute lynchpin. To kind of visualize this for you listening, 137 00:07:19.879 --> 00:07:21.480 think about it like this. If I have a wind 138 00:07:21.519 --> 00:07:23.839 tunnel and I blow a ten knot wind over a 139 00:07:23.879 --> 00:07:26.800 basin of tap water, I get immediate ripples right instantly. 140 00:07:26.879 --> 00:07:27.120 Yeah. 141 00:07:27.120 --> 00:07:29.279 But if I swap that water for something really thick, 142 00:07:29.360 --> 00:07:31.759 like a bowl of thick honey or heavy syrup, that 143 00:07:31.920 --> 00:07:35.360 exact same tennot wind does practically nothing right. 144 00:07:35.439 --> 00:07:38.839 The sheer stress isn't sufficient to overcome the syrup's resistance 145 00:07:38.879 --> 00:07:40.439 to being deformed exactly. 146 00:07:40.959 --> 00:07:44.480 The physical effort required is vastly different. The momentum from 147 00:07:44.519 --> 00:07:47.079 the air mass just kind of slips over the top layer. 148 00:07:47.279 --> 00:07:51.000 Yeah, the kinetic energy dissipates as microscopic heat rather than 149 00:07:51.040 --> 00:07:55.160 translating into actual wave motion. So by proving that planet 150 00:07:55.199 --> 00:07:57.920 waves could account for this specific viscosity and density of 151 00:07:57.959 --> 00:08:01.279 water on Earth using the lake superior to the MIT 152 00:08:01.319 --> 00:08:03.199 team confirmed their math was rock. 153 00:08:03.079 --> 00:08:06.519 Solid, solid enough to handle the weird alien chemistry of 154 00:08:06.600 --> 00:08:08.319 liquid hydrocarbons precisely. 155 00:08:08.600 --> 00:08:11.720 So we take this perfectly validated model and we point 156 00:08:11.720 --> 00:08:13.360 it back at kracken Mare on Titan. 157 00:08:13.639 --> 00:08:16.319 Let's really look at those parameters, because it is wild. 158 00:08:16.879 --> 00:08:20.120 The liquid is a cryogenic mixture of methane and ethane. 159 00:08:20.439 --> 00:08:22.879 It is sitting at roughly minus two hundred and ninety 160 00:08:22.920 --> 00:08:26.680 degrees fahrenheit, so cold, unbelievably cold, and the density of 161 00:08:26.720 --> 00:08:29.399 liquid methane is about four hundred and twenty two kilograms 162 00:08:29.399 --> 00:08:32.440 per cubic meter. Compare that to Earth water, which is 163 00:08:32.519 --> 00:08:35.639 basically a thousand So this Titan liquid is less than 164 00:08:35.679 --> 00:08:37.279 half as dense as the water we drink. 165 00:08:37.440 --> 00:08:40.320 And then you have surface tension which is incredibly low 166 00:08:40.360 --> 00:08:44.679 on Titan. Methane molecules don't have the strong hydrogen bonds 167 00:08:44.679 --> 00:08:45.879 that water molecules do. 168 00:08:46.039 --> 00:08:47.799 Right, Water exist together exactly. 169 00:08:47.840 --> 00:08:51.679 Water is cohesive, but the force holding the surface of 170 00:08:51.679 --> 00:08:55.039 a methane lake together is incredibly weak. 171 00:08:55.159 --> 00:08:57.720 Okay, So then you factor in the gravity, he said earlier. 172 00:08:57.759 --> 00:09:01.679 It's zero point one four gramsificantly lower than Earth. So 173 00:09:01.720 --> 00:09:04.240 the restoring force, meaning the gravity that's trying to pull 174 00:09:04.279 --> 00:09:07.200 a wave crust back down to make the surface flat again, 175 00:09:07.679 --> 00:09:08.440 is minimal. 176 00:09:08.639 --> 00:09:12.080 But and this is the kicker, you still have the atmosphere. 177 00:09:12.320 --> 00:09:15.480 Titan's atmosphere is mostly nitrogen, just like Earth's, but it's 178 00:09:15.600 --> 00:09:18.200 much colder and denser. It exerts about one point five 179 00:09:18.240 --> 00:09:19.279 bar of surface pressure. 180 00:09:19.320 --> 00:09:21.519 Okay, So this is where I struggle with the visualization, 181 00:09:21.600 --> 00:09:23.559 and maybe you can help break this down. If the 182 00:09:23.600 --> 00:09:26.200 liquid is that light, right, and the surface tension is 183 00:09:26.240 --> 00:09:28.639 weak and the gravity is super low, but you have 184 00:09:28.720 --> 00:09:32.960 a dense, heavy atmosphere pushing across it, why does it 185 00:09:33.039 --> 00:09:37.159 form a cohesive ten foot wave? That is the big question, right, 186 00:09:37.320 --> 00:09:40.840 Like why doesn't the atmospheric drag just rip the top 187 00:09:40.919 --> 00:09:43.679 layer of the methane off into a fine aerosol mist. 188 00:09:44.279 --> 00:09:46.279 I mean if I take a high pressure air hose 189 00:09:46.320 --> 00:09:49.120 and blast a puddle of gasoline, I don't get waves. 190 00:09:49.159 --> 00:09:50.519 I get a spray of vapor. 191 00:09:50.879 --> 00:09:53.480 Yeah, it's a totally fair question. It comes down to 192 00:09:53.519 --> 00:09:57.480 a question of kinetic scale and atmospheric density. You aren't 193 00:09:57.519 --> 00:10:00.519 hitting the lake with a highly localized, high la velocity 194 00:10:00.639 --> 00:10:02.240 jet of air like from a hose. 195 00:10:02.399 --> 00:10:02.720 Ah. 196 00:10:02.759 --> 00:10:05.840 Okay, the low wind speeds on Titan. Remember that two 197 00:10:05.919 --> 00:10:08.639 to three mile prour breeze we talk about. That means 198 00:10:08.720 --> 00:10:12.000 the dynamic pressure exerted by the wind is actually quite low, 199 00:10:12.240 --> 00:10:13.679 even though the atmosphere itself is death. 200 00:10:13.720 --> 00:10:15.799 So what's spreading the force out exactly? 201 00:10:16.279 --> 00:10:19.039 The planet? Waves calculation show that the wind transfers its 202 00:10:19.039 --> 00:10:22.679 momentum across a vast surface area, and it does this 203 00:10:22.759 --> 00:10:26.039 without ever exceeding the threshold where aerodynamic sheer would rip 204 00:10:26.080 --> 00:10:26.840 the fluid apart. 205 00:10:27.039 --> 00:10:28.600 Oh wow, so it's almost gentle. 206 00:10:28.840 --> 00:10:31.720 It is. In fact, the thick atmosphere actually acts as 207 00:10:31.720 --> 00:10:35.840 a stabilizing blanket. It presses down uniformly, maintaining the fluid 208 00:10:35.840 --> 00:10:39.279 phase of the methane, while the wind slowly steadily piles 209 00:10:39.320 --> 00:10:41.440 that light liquid up into a crest. 210 00:10:41.399 --> 00:10:44.799 And because there's almost no gravity fighting that upward lift, 211 00:10:45.200 --> 00:10:47.480 the crest just keeps building and building. 212 00:10:47.279 --> 00:10:50.320 Exactly, and that lack of gravitational restoring force is what 213 00:10:50.440 --> 00:10:53.799 dictates the whole kinematics of the wave. Think about Earth. 214 00:10:54.519 --> 00:10:58.320 On Earth, a ten foot wave crest is incredibly heavy. 215 00:10:58.720 --> 00:11:02.720 Gravity pulls it down violently. That's what creates the rapid 216 00:11:02.759 --> 00:11:05.320 crashing turbulence we see when we go surfing. 217 00:11:05.200 --> 00:11:07.639 Right, that classic crashing sound and foam. 218 00:11:07.840 --> 00:11:10.600 But on Titan, the mass of that methane crest is 219 00:11:10.720 --> 00:11:13.480 very low and the gravity pulling it down is very weak, 220 00:11:13.960 --> 00:11:17.240 so the acceleration of the falling fluid is drastically reduced. 221 00:11:17.679 --> 00:11:20.360 It literally takes longer for the methane to succumb. 222 00:11:20.080 --> 00:11:23.960 To gravity, which creates that cinematic suspended slow motion effect 223 00:11:24.080 --> 00:11:27.320 as it breaks against the shoreline. It's just so mine bending. 224 00:11:27.159 --> 00:11:30.799 It really is. And returning to the MIT team's original objective, 225 00:11:31.279 --> 00:11:34.679 this completely solves the mystery of the missing deltas right. 226 00:11:34.679 --> 00:11:36.919 Because a two mile per hour breeze on Earth does 227 00:11:36.960 --> 00:11:39.919 absolutely nothing to a shoreline, but a two mile per 228 00:11:39.919 --> 00:11:43.120 hour breeze on Titan generates a ten foot slow motion 229 00:11:43.320 --> 00:11:46.559 wall of liquid methane that is carrying a massive amount 230 00:11:46.559 --> 00:11:47.480 of kinetic energy. 231 00:11:47.720 --> 00:11:52.000 Exactly. The river networks on Titan are undoubtedly carrying sediment 232 00:11:52.039 --> 00:11:55.080 down to the coasts. It's likely crushed water, ice and 233 00:11:55.159 --> 00:12:00.000 hydrocarbon particulates. But the moment those rivers meet the lags, 234 00:12:00.440 --> 00:12:04.759 they just get they get pulverized. The relentless, easily generated 235 00:12:04.799 --> 00:12:09.519 wave action just destroys the deposits. The coastal erosion vastly 236 00:12:09.559 --> 00:12:12.919 outpaces the sediment deposition, so the deltas are being destroyed 237 00:12:12.960 --> 00:12:14.440 way faster than they can ever form. 238 00:12:14.720 --> 00:12:17.799 It's just a perfect synthesis of fluid dynamics answering a 239 00:12:17.840 --> 00:12:20.639 planetary anomaly. It's so satisfying, it really is. 240 00:12:21.000 --> 00:12:24.919 But Titan represents the system that's in relative equilibrium today. 241 00:12:25.240 --> 00:12:28.159 The planet waves model becomes even more revealing when we 242 00:12:28.200 --> 00:12:31.759 apply it chronologically to planetary bodies that have undergone massive 243 00:12:31.840 --> 00:12:32.799 changes over time. 244 00:12:32.639 --> 00:12:34.919 Which brings us to a really fascinating part of this 245 00:12:35.000 --> 00:12:36.639 deep dive Ancient Mars. 246 00:12:36.879 --> 00:12:39.399 Yes, the Noatian period of Mars. 247 00:12:39.240 --> 00:12:42.240 Right, because Mars is effectively the ultimate control group for 248 00:12:42.279 --> 00:12:46.120 atmospheric degradation. If you look at orbital telemetry of Mars today, 249 00:12:46.159 --> 00:12:50.240 you see this dry, irradiated dead desert, but the topography 250 00:12:50.279 --> 00:12:51.759 tells a completely different story. 251 00:12:51.960 --> 00:12:56.679 We have undeniable geomorphological evidence of a hydrological cycle on 252 00:12:56.759 --> 00:12:57.360 ancient Mars. 253 00:12:57.559 --> 00:12:59.519 Yeah, and the most famous example right now, the one 254 00:12:59.519 --> 00:13:04.279 everyone's is jezuro Crater. NASA's Perseverance rover is literally driving 255 00:13:04.279 --> 00:13:06.799 around in there right now, precisely because it is an 256 00:13:06.879 --> 00:13:11.519 ancient paleo lake basin, and unlike Titan, jesuro Crater has 257 00:13:11.639 --> 00:13:14.399 a magnificent, beautifully preserved delta. 258 00:13:14.399 --> 00:13:18.399 Which mathematically confirms something huge. It confirms that the wave 259 00:13:18.440 --> 00:13:21.799 action in jezro Crater billions of years ago was not 260 00:13:21.919 --> 00:13:24.720 powerful enough to erode the sediment being deposited by the 261 00:13:24.759 --> 00:13:25.480 inflowing river. 262 00:13:25.720 --> 00:13:28.039 Right so the water was relatively calm, or at least 263 00:13:28.039 --> 00:13:30.840 the waves weren't titaned sized monsters. 264 00:13:30.480 --> 00:13:33.679 Exactly, But the conditions of that wave action were not static. 265 00:13:34.039 --> 00:13:37.320 They changed dramatically during the no action period, which was 266 00:13:37.399 --> 00:13:41.120 roughly four billion years ago. Mars possessed a global magnetic field. 267 00:13:41.360 --> 00:13:43.720 It was generated by an active core, just like. 268 00:13:43.720 --> 00:13:47.240 Earth's, and that magnetic dynamo protected the atmosphere from the 269 00:13:47.240 --> 00:13:49.879 solar wind, which meant it could hold on to a 270 00:13:49.919 --> 00:13:52.840 thick atmosphere, which in turn allowed for liquid water to 271 00:13:52.919 --> 00:13:53.919 just sit on the surface. 272 00:13:54.320 --> 00:13:59.919 Right. But then the Martian core cooled, the magnetic dynamo failed, 273 00:14:00.440 --> 00:14:04.159 and the planet was suddenly exposed to continuous atmosphere expedtering. 274 00:14:04.279 --> 00:14:07.480 The solar wind just started sand blasting the planet exactly. 275 00:14:07.519 --> 00:14:10.559 It began stripping the upper atmosphere away molecule by. 276 00:14:10.399 --> 00:14:14.120 Molecule, and as that atmospheric envelope bled away into space, 277 00:14:14.519 --> 00:14:18.159 the pressure at the surface dropped. So the MIT team 278 00:14:18.200 --> 00:14:20.720 took the planet Waves model, locked in the gravity of 279 00:14:20.759 --> 00:14:23.639 Mars and the composition of liquid water, and they effectively 280 00:14:23.799 --> 00:14:26.000 ran the model backwards through time. 281 00:14:25.960 --> 00:14:28.600 Tracking the wave dynamics is the atmosphere. 282 00:14:28.120 --> 00:14:31.279 Thinned out, Yes, and the dynamic pressure of wind is 283 00:14:31.320 --> 00:14:35.360 governed by a specific equation right where pressure equals one 284 00:14:35.440 --> 00:14:38.600 half the fluid density times the velocity squared. So if 285 00:14:38.639 --> 00:14:42.200 the atmosphere density drops, the wind velocity has to increase 286 00:14:42.320 --> 00:14:45.799 exponentially just to transfer the exact same amount of kinetic 287 00:14:45.919 --> 00:14:46.639 energy to the water. 288 00:14:46.720 --> 00:14:49.600 Think about it like, this wind is just moving air. 289 00:14:49.720 --> 00:14:52.639 It's molecules in motion. The mass of the air on 290 00:14:52.720 --> 00:14:56.360 Mars physically decreased over time a forty mile per hour 291 00:14:56.440 --> 00:14:59.200 wind in a thick atmosphere carries billions of tons of 292 00:14:59.240 --> 00:15:02.360 kinetic energy because of the sheer density of molecules impacting 293 00:15:02.399 --> 00:15:02.759 the water. 294 00:15:03.000 --> 00:15:05.360 Right, there's just more physical stuff hitting the water. 295 00:15:05.320 --> 00:15:08.240 Exactly, But a forty mile per hour wind in a 296 00:15:08.320 --> 00:15:12.720 really thin atmosphere, it's mostly empty space. It exerts barely 297 00:15:12.759 --> 00:15:14.159 any physical sheer stress. 298 00:15:14.360 --> 00:15:17.120 So if you imagine setting up a time lapse camera 299 00:15:17.240 --> 00:15:19.879 on the shores of Jezero Crater millions of years ago, 300 00:15:20.279 --> 00:15:24.360 the model basically illustrates a dying ocean. In the early days, 301 00:15:24.519 --> 00:15:28.159 regular seasonal weather patterns could weep up totally normal surface waves. 302 00:15:28.679 --> 00:15:31.759 But as the air literally thinned out over tens of 303 00:15:31.799 --> 00:15:36.240 millions of years, the exact same storms rolling in century after. 304 00:15:36.159 --> 00:15:38.399 Century, the same wind velocity. 305 00:15:38.000 --> 00:15:41.480 Yeah, the exact same speeds became increasingly impotent. The water 306 00:15:41.559 --> 00:15:43.559 was still there, the wind was still moving at forty 307 00:15:43.559 --> 00:15:46.120 miles per hour, but the waves just started getting smaller 308 00:15:46.120 --> 00:15:46.720 and smaller. 309 00:15:46.799 --> 00:15:50.639 It would require increasingly extreme massive gales just to make 310 00:15:50.639 --> 00:15:54.200 a splash, let alone generate the baseline wave heights of 311 00:15:54.240 --> 00:15:55.080 previous eras. 312 00:15:55.279 --> 00:16:00.000 Wow, you are literally watching the mechanical transfer of play 313 00:16:00.000 --> 00:16:04.440 planetary energy just grind to a halt. The geological engine 314 00:16:04.440 --> 00:16:07.759 that powered coastal erosion on Mars slowly suffocated as the 315 00:16:07.799 --> 00:16:11.159 atmosphere vanished. By the time the lakes ultimately froze or 316 00:16:11.200 --> 00:16:15.320 evaporated away, their surfaces were likely completely stagnant, no matter 317 00:16:15.360 --> 00:16:16.639 how fast the wind was blowing. 318 00:16:16.840 --> 00:16:20.360 It's a pretty chilling visualization of planetary mortality on it. 319 00:16:20.120 --> 00:16:23.720 It really is. So we've looked at Earth as the baseline, 320 00:16:24.039 --> 00:16:28.039 We've looked at Titan as the low gravity alien chemistry extreme, 321 00:16:28.559 --> 00:16:31.759 and we've looked at Mars as the decaying atmosphere variable. 322 00:16:32.159 --> 00:16:33.840 But what I love about this research is that they 323 00:16:33.840 --> 00:16:34.720 didn't stop there. 324 00:16:34.840 --> 00:16:36.679 Oh No, they pushed it way further. 325 00:16:36.600 --> 00:16:38.840 To stress test the math to make sure it wasn't 326 00:16:38.879 --> 00:16:42.000 just biased toward our local Solar system physics. They pushed 327 00:16:42.080 --> 00:16:46.120 the parameters to the absolute, terrifying extremes by applying planet 328 00:16:46.159 --> 00:16:47.279 waves to exoplanets. 329 00:16:47.360 --> 00:16:50.600 Yeah, testing against extreme parameter spaces is vital if you 330 00:16:50.600 --> 00:16:52.879 want to confirm the integrity of physico model, Yeah, you 331 00:16:52.919 --> 00:16:54.039 have to try and break it right. 332 00:16:54.120 --> 00:16:58.120 So they modeled three entirely distinct classes of exoplanets. Let's 333 00:16:58.120 --> 00:16:59.639 start with LHS one forty B. 334 00:17:00.159 --> 00:17:02.519 This one has been heavily studied by the James Webb 335 00:17:02.600 --> 00:17:06.480 Space Telescope. It classifies as a super Earth, and it 336 00:17:06.640 --> 00:17:09.279 orbits in the habitable zone of a red dwarf star. 337 00:17:09.839 --> 00:17:13.039 It's a rocky world roughly one point seven times the 338 00:17:13.119 --> 00:17:16.039 radius of Earth, and its mass suggests it could easily 339 00:17:16.119 --> 00:17:19.799 host vast oceans of liquid water. But the gravity on 340 00:17:20.039 --> 00:17:22.119 LHS eleven forty b is. 341 00:17:22.160 --> 00:17:25.880 Immense, which creates an incredibly extreme environment for that restoring 342 00:17:25.880 --> 00:17:28.759 force we talked about earlier. When wind sheer attempts to 343 00:17:28.759 --> 00:17:31.079 deform the surface of the water on this super Earth, 344 00:17:31.319 --> 00:17:33.559 it is fighting a massive gravitational anchor. 345 00:17:33.680 --> 00:17:36.400 The gravity is just pulling it down so hard exactly. 346 00:17:36.640 --> 00:17:39.319 The kinetic energy required to lift a volume of water 347 00:17:39.480 --> 00:17:42.279 is drastically higher than on Earth. So the planet waves 348 00:17:42.279 --> 00:17:45.240 calculations indicate that a windstorm that would generate say a 349 00:17:45.359 --> 00:17:46.400 six foot swell on. 350 00:17:46.279 --> 00:17:48.640 Earth like a really decent surfing one right. 351 00:17:48.759 --> 00:17:51.720 That exact same windstorm might only manage a turbulent chop 352 00:17:51.759 --> 00:17:54.319 of a few inches on this super Earth. The water 353 00:17:54.400 --> 00:17:56.759 is effectively pinned to the ocean floor by gravity. 354 00:17:57.039 --> 00:18:01.400 That is wild, and that introduces some really fascinating implications 355 00:18:01.440 --> 00:18:04.880 for oceanic circulation, doesn't it like thermal distribution on a 356 00:18:04.880 --> 00:18:08.480 planet like that. If you lack deep water wave propagation, 357 00:18:08.680 --> 00:18:11.480 the mixing of nutrients and heat might be severely stunted. 358 00:18:11.880 --> 00:18:15.279 The oceans might just be these heavily stratified, stagnant layers. 359 00:18:15.519 --> 00:18:18.960 It completely changes how we think about habitability. But then 360 00:18:19.240 --> 00:18:23.440 they shifted from manipulating gravity to manipulating the fluid itself. 361 00:18:24.279 --> 00:18:26.920 The team analyzed Kepler sixteen forty nine b. 362 00:18:27.119 --> 00:18:29.960 Okay, so this one is terrestrial, roughly Earth sized, so 363 00:18:30.000 --> 00:18:33.799 the gravity is familiar, but astrobiologists theorize it operates as 364 00:18:33.799 --> 00:18:37.960 an exovenus, which means it likely possesses surface liquids composed 365 00:18:38.000 --> 00:18:40.599 not of water but of sulfuric acid, and. 366 00:18:40.559 --> 00:18:43.640 The reality of sulfuric acid is a completely different beast entirely. 367 00:18:43.839 --> 00:18:47.240 We know it's highly corrosive, obviously, but mechanically speaking, it 368 00:18:47.279 --> 00:18:49.960 is incredibly dense. It has a density of roughly eighteen 369 00:18:50.079 --> 00:18:51.559 hundred and thirty kilograms per. 370 00:18:51.480 --> 00:18:54.000 Cubic meter, which is nearly double that of liquid water. 371 00:18:54.319 --> 00:18:57.440 Exactly so, even with Earth normal gravity, the sheer mass 372 00:18:57.519 --> 00:19:01.079 of the fluid requires intense aerodynamic drag just to initiate 373 00:19:01.079 --> 00:19:02.599 that very first capillary wave. 374 00:19:02.920 --> 00:19:07.039 You're dealing with extreme fluid inertia. A standard earth breeze 375 00:19:07.079 --> 00:19:10.279 simply lacks the physical momentum to overcome the density of 376 00:19:10.279 --> 00:19:13.240 the acid lakes. The wind would just flow right over 377 00:19:13.279 --> 00:19:15.839 the boundary layer with almost zero energy transfer. 378 00:19:15.920 --> 00:19:21.160 It requires extreme violent atmospheric velocities to generate any meaningful 379 00:19:21.200 --> 00:19:22.559 wave action on that planet. 380 00:19:22.680 --> 00:19:25.720 Okay, but even that pales in comparison to the ultimate 381 00:19:25.799 --> 00:19:29.680 stress test. They applied the model to fifty five Cankori. 382 00:19:30.039 --> 00:19:30.960 This is the lava world. 383 00:19:31.200 --> 00:19:34.680 Yes, the lava world. It's a tidally locked super Earth 384 00:19:34.799 --> 00:19:37.039 orbiting so close to its host star that the day 385 00:19:37.079 --> 00:19:40.920 side temperature exceeds four thousand degrees fahrenheit. The planet is 386 00:19:41.039 --> 00:19:45.680 literally covered in a global ocean of silicate magma liquid rock. 387 00:19:46.200 --> 00:19:49.119 This pushes the planet waves model to the absolute boundary 388 00:19:49.119 --> 00:19:52.680 of fluid mechanics because magma doesn't behave like a simple 389 00:19:52.720 --> 00:19:56.640 Newtonian fluid like water or even methane. How So, depending 390 00:19:56.640 --> 00:20:00.079 on the silica content and the temperature, magma often acts 391 00:20:00.160 --> 00:20:01.359 as a Bingham plastic. 392 00:20:01.519 --> 00:20:03.799 A Bingham plastic what does that mean? In this context? 393 00:20:04.039 --> 00:20:07.359 It means it has a yield stress, so it actually 394 00:20:07.359 --> 00:20:11.359 behaves like a solid until a specific threshold of sheer 395 00:20:11.400 --> 00:20:14.160 stress is applied to it. Only when that threshold is 396 00:20:14.240 --> 00:20:16.599 met does it actually begin to flow like a liquid. 397 00:20:16.680 --> 00:20:19.160 Oh wow, So it's fighting the wind not just with weight, 398 00:20:19.200 --> 00:20:20.839 but with its fundamental state. 399 00:20:20.640 --> 00:20:24.079 Of matter exactly. And the viscosity is just staggering. The 400 00:20:24.119 --> 00:20:28.839 internal friction resisting deformation is astronomically high. We are talking 401 00:20:28.839 --> 00:20:32.359