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 00:00:26.960 --> 00:00:29.600 If you're looking for the most efficient shortcut to being 8 00:00:29.600 --> 00:00:32.399 fully informed on the cutting edge of science, you were 9 00:00:32.399 --> 00:00:35.320 in the right place. We take the source material, a 10 00:00:35.359 --> 00:00:38.880 breaking study, a massive data dump, and we just we 11 00:00:39.000 --> 00:00:42.280 distill it down into the core fascinating insights you need. 12 00:00:42.399 --> 00:00:46.200 And today we are undertaking a bit of a cosmic exploration. 13 00:00:46.679 --> 00:00:49.759 We're looking at a world that has for decades really 14 00:00:49.880 --> 00:00:52.719 represented our greatest hope for finding life beyond Earth, at 15 00:00:52.799 --> 00:00:54.039 least in our own solar system. 16 00:00:54.119 --> 00:00:58.479 We're talking about Jupiter's spectacular ice covered moon, Europa exactly, 17 00:00:58.600 --> 00:01:02.079 Europa is I mean, it's an absolute magnet for speculation, 18 00:01:02.479 --> 00:01:05.680 and for really good reason. Jupiter, the gas giant, it 19 00:01:05.799 --> 00:01:08.519 Shepper's nearly one hundred boons. It's an astronomical number. 20 00:01:08.519 --> 00:01:11.560 Truly, it is a whole solar system in itself. 21 00:01:11.000 --> 00:01:14.400 But Europa just stands out completely. The consensus among planetary 22 00:01:14.400 --> 00:01:17.840 scientists is that it harbors this vast global ocean of 23 00:01:18.400 --> 00:01:22.560 liquid salt water, and it's completely hidden beneath an icy excurior. 24 00:01:22.640 --> 00:01:24.599 It's a true water world, and it's isolated from the 25 00:01:24.599 --> 00:01:27.680 Sun's energy, which makes it well the ultimate enigma. 26 00:01:27.719 --> 00:01:31.319 It is the ultimate enigma. Yeah, but that potential for life, 27 00:01:31.400 --> 00:01:35.719 for habitability, it's always hinge on one single critical question. 28 00:01:36.040 --> 00:01:39.680 It's not simply does Europa have water, because I mean, 29 00:01:39.680 --> 00:01:40.879 we're highly confident that it does. 30 00:01:41.000 --> 00:01:43.680 Oh, absolutely, the evidence for the ocean is very strong. 31 00:01:44.040 --> 00:01:46.920 The real question, the one that matters, is does it 32 00:01:46.959 --> 00:01:50.560 have the dynamic energy that life needs to actually arise 33 00:01:50.640 --> 00:01:52.680 and sustain itself within that. 34 00:01:52.719 --> 00:01:56.640 Water And that distinction that is the absolute core of 35 00:01:56.680 --> 00:01:59.239 our analysis today. Yeah, the difference between just having the 36 00:01:59.280 --> 00:02:02.439 liquid the solve and having the active chemical engine. Right, 37 00:02:02.599 --> 00:02:05.239 we're pulling insights from a brand new peer reviewed study 38 00:02:05.280 --> 00:02:08.120 who was just published in the journal Nature Communications. This 39 00:02:08.199 --> 00:02:11.120 research it was led by Paul Byrne at Washington University 40 00:02:11.120 --> 00:02:13.879 in Saint Louis, and they looked past the water itself. 41 00:02:13.919 --> 00:02:17.080 They focused intensely on the geology. 42 00:02:16.479 --> 00:02:19.520 Of the seafloor, and their findings are well, they're significant. 43 00:02:19.680 --> 00:02:22.759 They suggest we might need to radically recalibrate our expectations 44 00:02:22.800 --> 00:02:27.680 about Europa. The team used physics and some really detailed 45 00:02:27.680 --> 00:02:30.840 geological modeling to pour what you might call cold water 46 00:02:31.000 --> 00:02:31.960 part in the stellar pun. 47 00:02:32.159 --> 00:02:34.000 Huh, Yeah, I was waiting for that one on. 48 00:02:33.960 --> 00:02:37.319 The long held excitement about Europa's potential to support life, 49 00:02:37.400 --> 00:02:39.120 at least life on its ocean floor. 50 00:02:39.199 --> 00:02:42.120 Okay, let's unpack this. What this new study is suggesting 51 00:02:42.280 --> 00:02:44.840 is that the bottom of that vast ocean, maybe one 52 00:02:44.879 --> 00:02:48.639 hundred kilometers deep, is geologically. 53 00:02:47.879 --> 00:02:52.360 Silent, silent, static inert and that's silence. 54 00:02:52.400 --> 00:02:54.879 I mean, if the modeling holds true, that is a 55 00:02:54.919 --> 00:02:58.080 catastrophic problem for any life that relies on chemical energy. 56 00:02:58.159 --> 00:03:00.240 It's a huge problem. And the credibility of this work 57 00:03:00.319 --> 00:03:03.680 is it's very high. This isn't just speculation. It's published 58 00:03:03.719 --> 00:03:07.759 in a top tier journal and it's grounded in meticulous calculations. 59 00:03:08.039 --> 00:03:11.319 They're combining known physical facts about Europa. 60 00:03:11.039 --> 00:03:15.039 It's density, its size, how it orbits Jupiter, all. 61 00:03:14.879 --> 00:03:17.520 Of that, and they combine it with detailed inferences drawn 62 00:03:17.560 --> 00:03:20.319 from how small rocky bodies behave, you know, including Earth 63 00:03:20.360 --> 00:03:23.319 and our own moon. The team Burn and his colleagues, 64 00:03:23.479 --> 00:03:26.319 they focused all their energy on that often overlooked part 65 00:03:26.319 --> 00:03:27.680 of the puzzle, the seafloor. 66 00:03:28.159 --> 00:03:31.039 And this is exactly where we need to start. We 67 00:03:31.080 --> 00:03:34.439 are diving down past the ice, past the ocean, right 68 00:03:34.439 --> 00:03:37.360 to the bottom. So let's establish the scale of this 69 00:03:37.479 --> 00:03:39.960 place for you, the listener. Let's call this first part 70 00:03:40.360 --> 00:03:42.159 the anatomy of a water world. 71 00:03:42.400 --> 00:03:45.879 It really helps to visualize it. First, Europa. It's actually 72 00:03:46.479 --> 00:03:48.800 it's quite modest in size, a little bit smaller in 73 00:03:48.840 --> 00:03:50.639 diameter than our own moon, right, so. 74 00:03:50.599 --> 00:03:52.439 You'd think smaller world. 75 00:03:52.240 --> 00:03:55.919 Less stuff, you would, But that scale is completely deceptive 76 00:03:56.240 --> 00:03:59.759 because its structure, how it's built, gives it this disproportionate 77 00:04:00.199 --> 00:04:02.080 immense volume of water. 78 00:04:02.199 --> 00:04:05.120 It really is staggering. I read that if you could 79 00:04:05.159 --> 00:04:10.479 somehow gather all the liquid water on Earth, all our oceans, lakes, rivers, 80 00:04:10.560 --> 00:04:13.879 ice caps, everything, everything, Europa is modeled to hold more 81 00:04:13.960 --> 00:04:16.439 water than all of it combined, and the moon itself 82 00:04:16.480 --> 00:04:18.920 is just a fraction of Earth's mass. That just blows 83 00:04:18.959 --> 00:04:19.319 my mind. 84 00:04:19.399 --> 00:04:21.399 It's why the volume is so immense, and it's why 85 00:04:21.439 --> 00:04:24.199 this little moon has always held such promise that volume 86 00:04:24.240 --> 00:04:27.319 is organized into three, three distinct layers. 87 00:04:27.439 --> 00:04:28.720 Okay, so let's start at the top. 88 00:04:29.000 --> 00:04:34.519 First, you have the ceiling, the ice shell. Current estimates 89 00:04:34.600 --> 00:04:37.199 they put that shield of ice at somewhere between fifteen 90 00:04:37.240 --> 00:04:38.680 and twenty five kilometers thick. 91 00:04:38.759 --> 00:04:42.319 Fifteen to twenty five kilometers. That is a colossal barrier 92 00:04:42.680 --> 00:04:44.759 between the surface and anything below it. 93 00:04:44.759 --> 00:04:49.639 An incredible barrier. Then beneath that shield lies the ocean itself, 94 00:04:50.199 --> 00:04:52.399 and it's not some shallow sea. We're talking about a 95 00:04:52.399 --> 00:04:53.920 depth of up to one hundred. 96 00:04:53.720 --> 00:04:57.160 Kilometers one hundred kilometers deep, I mean, just from perspective, 97 00:04:57.199 --> 00:04:59.560 that's ten times deeper than the Marianna's Trench, which is 98 00:04:59.560 --> 00:05:01.160 the deepest point we have here on Earth. 99 00:05:01.160 --> 00:05:04.959 Precisely it covers the entire Moon. And then finally, beneath 100 00:05:05.000 --> 00:05:09.000 that immense volume of salty liquid water, that's where you 101 00:05:09.040 --> 00:05:12.879 find the third layer, a rocky core. It's analogous to 102 00:05:12.920 --> 00:05:15.199 the silicate rock mantle and core of Earth. 103 00:05:15.360 --> 00:05:17.600 So you have the fundamental building blocks. You have liquid 104 00:05:17.600 --> 00:05:18.120 water and you. 105 00:05:18.079 --> 00:05:19.879 Have rock, the two main ingredients. 106 00:05:19.959 --> 00:05:22.040 But as you put it out earlier, having water and 107 00:05:22.160 --> 00:05:25.040 rock is what two thirds of the equation you need energy, 108 00:05:25.639 --> 00:05:29.360 So what makes that rock water interface, that seafloor so 109 00:05:29.560 --> 00:05:32.759 absolutely essential for life in this dark, sunless environment. 110 00:05:33.079 --> 00:05:36.120 Yeah, this is key. We have to completely move past 111 00:05:36.160 --> 00:05:39.959 the Earth based idea of photosynthesis. I mean, in a cold, 112 00:05:40.160 --> 00:05:43.800 dark deep sea environment like that, life can't rely on 113 00:05:43.839 --> 00:05:46.560 the sun. There is no sun, so instead it has 114 00:05:46.600 --> 00:05:51.319 to rely on chemical energy. It's a process we call chemototrophy. 115 00:05:50.800 --> 00:05:53.240 And we have examples of this on Earth. You have 116 00:05:53.319 --> 00:05:58.040 to think about those incredible, almost alien looking deep sea ecosystems. 117 00:05:58.079 --> 00:06:02.480 We've discovered, the ones cluster miles beneath the surface, completely 118 00:06:02.519 --> 00:06:04.720 cut off from the light exactly. We're talking about those 119 00:06:04.759 --> 00:06:09.879 giant tube worms, the colossal clams, all those specialized microbial 120 00:06:09.959 --> 00:06:11.639 mats living in total darkness. 121 00:06:11.680 --> 00:06:13.959 And those organisms they're not living off the sun. They 122 00:06:14.000 --> 00:06:18.319 are living off Earth's internal geological engine. That engine, it's 123 00:06:18.439 --> 00:06:22.160 driven by tectonic motion and volcanic activity, and it manifests 124 00:06:22.240 --> 00:06:25.079 as hydrothermal vents or ex smokers, the black smokers. 125 00:06:25.160 --> 00:06:25.399 Yeah. 126 00:06:25.519 --> 00:06:28.600 What happens is cold ocean water seeps down into the crust, 127 00:06:28.839 --> 00:06:32.600 it encounters these superheated magma chambers and it gets chemically altered. 128 00:06:32.639 --> 00:06:34.759 It's cooked, so it picks up all sorts of minerals 129 00:06:34.759 --> 00:06:35.439 and compounds. 130 00:06:35.680 --> 00:06:38.040 It does, and that water then shoots back out through 131 00:06:38.040 --> 00:06:41.680 these vents at extremely high temperatures, carrying this rich chemical. 132 00:06:41.279 --> 00:06:44.759 Soup with it, and it's that superheated plume, that chemical 133 00:06:45.240 --> 00:06:48.879 disequilibrium that is the literal catalyst for life. 134 00:06:48.920 --> 00:06:51.720 That's the perfect word for it, catalyst. The water coming 135 00:06:51.759 --> 00:06:55.759 out of those vents is rich in compounds like hydrogen sulfide, 136 00:06:55.839 --> 00:07:00.959 iron sulfides, methane, manganese, all these things that my microbes can. 137 00:07:01.040 --> 00:07:03.040 Well eat, they can metabolize it. 138 00:07:03.000 --> 00:07:07.160 And metabolize it. These compounds, especially hydrogen sulfide, provide the 139 00:07:07.319 --> 00:07:10.720 energy needed to kickstart and sustain microbial life at the 140 00:07:10.800 --> 00:07:15.120 absolute base of the food chain. The microbes consume those chemicals, 141 00:07:15.199 --> 00:07:18.040 and then everything else in that ecosystem consumes the microbes. 142 00:07:18.120 --> 00:07:21.959 So without that active geology, without that mechanism for energy 143 00:07:21.959 --> 00:07:23.480 cycling and chemical. 144 00:07:23.120 --> 00:07:27.319 Injection, then even one hundred kilometer deep ocean becomes a vast, cold, 145 00:07:27.480 --> 00:07:31.240 inert volume. It's just water and rock with no spark. 146 00:07:31.519 --> 00:07:33.680 This is where that Burn study just hit so hard. 147 00:07:34.079 --> 00:07:36.639 They looked at the Earth analogy and they calculated the 148 00:07:36.639 --> 00:07:40.800 odds of Europa providing those vents, and burn was very clear. 149 00:07:41.079 --> 00:07:43.839 When he presented his team's conclusion, he said, and this 150 00:07:44.000 --> 00:07:46.879 really drives the point home. If we could explore that 151 00:07:46.920 --> 00:07:50.319 ocean with a remote control submarine, we predict we wouldn't 152 00:07:50.360 --> 00:07:53.959 see any new fractures, active volcanoes, or plumes of hot 153 00:07:54.000 --> 00:07:55.040 water on the seafloor. 154 00:07:55.360 --> 00:07:58.360 And the implication of that statement is immediate and it's profound. 155 00:07:58.879 --> 00:08:01.600 If the seafloor is quiet, just like the model suggests, 156 00:08:01.839 --> 00:08:04.920 then there's no mechanism for cycling necessary nutrients from the 157 00:08:05.000 --> 00:08:06.399 rocky core up into the. 158 00:08:06.360 --> 00:08:09.319 Water, and no way to provide that vital thermal energy. 159 00:08:09.720 --> 00:08:12.959 None the energy required to sustain a deep sea chemo 160 00:08:13.000 --> 00:08:17.560 autotrophic ecosystem just isn't there. The lack of geologic activity 161 00:08:17.560 --> 00:08:20.759 at that vital rock water boundary, it essentially means the 162 00:08:20.800 --> 00:08:24.000 available energy is negligible. The ocean floor might as well 163 00:08:24.040 --> 00:08:25.480 be a geologically dead zone. 164 00:08:25.519 --> 00:08:26.959 But wait, I have to stop you on that point 165 00:08:27.000 --> 00:08:29.879 before we pivot to the calculation itself. Is it possible 166 00:08:30.240 --> 00:08:32.519 that just the fact that there is a rock water 167 00:08:32.600 --> 00:08:36.559 interface and that the water is salty, is that enough 168 00:08:36.960 --> 00:08:40.639 to produce some chemistry even without the big dramatic vents. 169 00:08:40.879 --> 00:08:42.120 That's a crucial question. 170 00:08:42.320 --> 00:08:45.559 Could in simple rock dissolution or reactions between the salt 171 00:08:45.600 --> 00:08:48.360 and the silicates produce some energy, even a little bit. 172 00:08:48.480 --> 00:08:50.320 It's a crucial point, and it moves us into a 173 00:08:50.399 --> 00:08:53.399 realm of let's call it lower energy life support. And 174 00:08:53.480 --> 00:08:57.120 yes it's possible, but the challenge there is immense Simple 175 00:08:57.360 --> 00:09:02.440 water rock reactions they happen everywhere, but they are incredibly slow, diffuse, 176 00:09:02.720 --> 00:09:04.799 very diffuse, and they don't release a lot of energy. 177 00:09:05.279 --> 00:09:08.320 Hydrothermal vents, on the other hand, driven by active tectonics 178 00:09:08.320 --> 00:09:12.879 and volcanism, they create an intense, localized disequilibrium, a sudden, 179 00:09:13.000 --> 00:09:16.679 dramatic injection of heat and chemicals. That's what allows life 180 00:09:16.679 --> 00:09:20.639 to thrive rapids accentrated source exactly. The Burn's study is 181 00:09:20.679 --> 00:09:24.399 primarily arguing that Europa lacks that powerful engine, the one 182 00:09:24.399 --> 00:09:28.480 that creates these high energy oases. So without that strong 183 00:09:28.600 --> 00:09:32.240 geological motor, any chemistry that does occur would be spread 184 00:09:32.360 --> 00:09:35.200 so thin, so slowly that it might not be enough 185 00:09:35.240 --> 00:09:37.759 to initiate or sustain a thriving ecosystem. 186 00:09:38.000 --> 00:09:40.440 That makes perfect sense. We're not just looking for a 187 00:09:40.480 --> 00:09:43.600 low energy trickle here, We're looking for the powerhouse, the 188 00:09:43.639 --> 00:09:47.279 thing that creates a concentrated biological starting point. So the 189 00:09:47.320 --> 00:09:50.960 big question is how do they reach this quiet conclusion. 190 00:09:51.919 --> 00:09:54.240 This brings us to the scientific heart of the study, 191 00:09:54.279 --> 00:09:57.600 which is the physics and the calculation itself. So let's 192 00:09:57.600 --> 00:09:58.960 talk about it. Where did the heat go? 193 00:09:59.320 --> 00:10:03.279 Absolutely the researchers, they relied on some really fundamental planetary 194 00:10:03.279 --> 00:10:06.559 physics and gravitational modeling. They had to figure out whether 195 00:10:06.639 --> 00:10:10.320 Europa possesses enough internal heat to cause that significant motion 196 00:10:10.440 --> 00:10:14.320 required for say, plate tectonics or volcanism at the seafloor. 197 00:10:14.440 --> 00:10:16.320 And they looked at two main heat sources. 198 00:10:16.399 --> 00:10:18.799 Right, two main sources. Yes, The first is the internal 199 00:10:18.799 --> 00:10:21.600 furnace residual heat, the heat left over from when the 200 00:10:21.639 --> 00:10:22.559 Moon first formed. 201 00:10:22.759 --> 00:10:26.960 Okay, so source number one. Why is Earth's core still 202 00:10:27.080 --> 00:10:31.320 blazing hot billions of years later? Yet Europa's core is 203 00:10:31.360 --> 00:10:34.000 predicted to be, you know, thermally inert. 204 00:10:34.320 --> 00:10:37.840 It's a classic example of how scale, just sheer size 205 00:10:37.919 --> 00:10:41.639 affects how a planet cools over cosmic time. Imagine you 206 00:10:41.679 --> 00:10:44.799 have a small cup of hot coffee versus a massive 207 00:10:44.960 --> 00:10:46.679 insulated urn of coffee. 208 00:10:46.759 --> 00:10:47.440 Okay, I'm waiting. 209 00:10:47.519 --> 00:10:50.039 They both start out hot, but the small cup. Because 210 00:10:50.039 --> 00:10:52.879 it has a low mass to surface area ratio, it 211 00:10:52.960 --> 00:10:56.240 loses its heat very very quickly to the surrounding air. 212 00:10:56.360 --> 00:10:59.759 Right it cools down in minutes. And Earth is the 213 00:10:59.799 --> 00:11:02.919 massive urn, holding onto its heat much more efficiently. 214 00:11:03.039 --> 00:11:06.559 Precisely, Earth is large enough. It's massive enough that it 215 00:11:06.600 --> 00:11:09.600 retains heat not just from its primordial formation, but also 216 00:11:09.679 --> 00:11:13.279 from the ongoing decay of radioactive isotopes within its mantle, 217 00:11:13.639 --> 00:11:15.440 things like uranium and thorium, so. 218 00:11:15.320 --> 00:11:18.519 That radioactive decay acts like a long term, slow burning 219 00:11:18.679 --> 00:11:19.919 internal heating element. 220 00:11:20.080 --> 00:11:22.960 Exactly. It's what sustains the convection in our mantle and 221 00:11:23.039 --> 00:11:25.759 drives plate tectonics over billions of years. It keeps the 222 00:11:25.759 --> 00:11:26.519 engine running. 223 00:11:26.840 --> 00:11:29.879 But Europer, being comparable in size to our own moon, 224 00:11:30.360 --> 00:11:31.799 it's the small cup of coffee. 225 00:11:31.960 --> 00:11:35.200 Correct, Euroba simply lacks the thermal mass to hold on 226 00:11:35.240 --> 00:11:38.480 to that primorbial heat for very long. The sheer volume 227 00:11:38.519 --> 00:11:41.440 of rock and the insulation effect are just so much smaller. 228 00:11:42.360 --> 00:11:45.600 Burn and his team they calculated that any heat that 229 00:11:45.720 --> 00:11:49.240 was originally present in Europa's rocky core, it would have 230 00:11:49.399 --> 00:11:51.480 entirely dissipated into space. 231 00:11:51.480 --> 00:11:53.120 Radiating away through the crust and. 232 00:11:53.120 --> 00:11:55.480 The ocean billions of years ago. So by the time 233 00:11:55.480 --> 00:11:58.480 we observe Europa today, that internal furnace is predicted to 234 00:11:58.480 --> 00:12:01.240 be cold thermally speaking, of course, so. 235 00:12:01.279 --> 00:12:05.240 We can scratch off residual planetary heat that's not driving 236 00:12:05.279 --> 00:12:09.679 any contemporary seafloor activity. The core is cold. That means 237 00:12:09.720 --> 00:12:12.919 the only viable engine left for keeping the geology dynamic 238 00:12:13.200 --> 00:12:15.399 must come from the outside. 239 00:12:14.799 --> 00:12:17.759 From Jupiter itself. From Jupiter, and this is where we 240 00:12:17.799 --> 00:12:21.600 move into the incredibly dynamic and very powerful realm of 241 00:12:21.679 --> 00:12:25.159 tidal heating. This is a kinetic energy source. It's the 242 00:12:25.200 --> 00:12:28.840 mechanical flexing and friction that's generated by Jupiter's immense gravity, 243 00:12:29.120 --> 00:12:31.080 and that force is strong enough to keep a moon 244 00:12:31.120 --> 00:12:34.360 geologically alive even without any residual internal heat. 245 00:12:34.600 --> 00:12:37.960 Here's where the physics gets incredibly powerful and really where 246 00:12:37.960 --> 00:12:40.279 the difference between life and no life just hangs in 247 00:12:40.320 --> 00:12:44.240 the balance. We have to compare Europa to its incredibly 248 00:12:44.320 --> 00:12:46.840 volatile sibling Aoo. 249 00:12:46.240 --> 00:12:49.960 The tail of two moons exactly the Io Europa contrast is. 250 00:12:50.000 --> 00:12:53.120 I mean, it's the perfect teaching moment in planetary science. 251 00:12:53.200 --> 00:12:56.919 Io is quite literally the most volcanically active body we 252 00:12:57.000 --> 00:12:59.759 know of in the entire solar system. Its surface is 253 00:12:59.799 --> 00:13:03.080 just constantly being repaved by spectacular eruptions. 254 00:13:03.120 --> 00:13:06.559 And that phenomenal activity is one hundred percent driven by tidal. 255 00:13:06.279 --> 00:13:09.200 Heating one hundred percent. But it's not just from Jupiter's 256 00:13:09.240 --> 00:13:12.879 simple gravity. It's driven by the asymmetry of that gravity, 257 00:13:12.879 --> 00:13:14.120 the unevenness of the poll. 258 00:13:14.200 --> 00:13:16.720 Okay, So explain that asymmetry for us. What makes EO's 259 00:13:16.799 --> 00:13:20.000 orbit so special and so heating. So. 260 00:13:20.120 --> 00:13:24.000 EO is the innermost of Jupiter's four large Gallean moons, 261 00:13:24.399 --> 00:13:27.159 and crucially, its orbit is not a perfect circle. We 262 00:13:27.279 --> 00:13:29.240 describe it as eccentric or erratic. 263 00:13:29.440 --> 00:13:31.120 And why is that? Why hasn't it settled down? 264 00:13:31.279 --> 00:13:35.159 Well, this eccentricity is maintained by a complex gravitational dance, 265 00:13:35.279 --> 00:13:38.879 a resonance with Europa and Ganymede, It's two outer neighbors. 266 00:13:39.440 --> 00:13:42.039 As these moons past each other in their orbits, they 267 00:13:42.039 --> 00:13:46.080 give Io a periodic gravitational tug, a little nudge, And. 268 00:13:46.039 --> 00:13:48.720 That little tug is enough to prevent Io from settling 269 00:13:48.759 --> 00:13:52.480 into a nice, stable circular path. It keeps it wobbly. 270 00:13:52.200 --> 00:13:56.279 Exactly because its orbit is elliptical or oval shaped. Io 271 00:13:56.399 --> 00:13:58.840 is constantly moving a little closer to Jupiter, and then 272 00:13:58.879 --> 00:14:01.320 a little further away. When it's close to that gas giant, 273 00:14:01.440 --> 00:14:04.799 the gravitational poll is extreme. When it's further away, the 274 00:14:04.840 --> 00:14:09.240 pool relaxes a bit. This constant differential and uneven tugging 275 00:14:09.879 --> 00:14:13.159 it subjects EO to intense cyclical stress. 276 00:14:13.279 --> 00:14:16.080 It's like taking a rigid stress ball and just continuously 277 00:14:16.120 --> 00:14:19.320 squeezing and relaxing at thousands and thousands of times a year. 278 00:14:19.480 --> 00:14:22.159 The friction generated inside must be immense. 279 00:14:22.279 --> 00:14:25.600 That's a perfect analogy. The immense constant friction generated by 280 00:14:25.600 --> 00:14:28.960 this physical deformation, this tidal flexing is what converts kinetic 281 00:14:29.039 --> 00:14:32.440 energy into thermal energy. It roils the rocks beneath Io's 282 00:14:32.440 --> 00:14:36.360 crust so intensely that the Moon's interior is largely molten, which. 283 00:14:36.159 --> 00:14:40.919 Is what drives those massive, NonStop volcanic eruptions that spew 284 00:14:40.960 --> 00:14:42.960 out sulfur and silicate lava. 285 00:14:43.240 --> 00:14:47.480 Io is truly alive because of Jupiter's intense asymmetrical gravitational 286 00:14:47.559 --> 00:14:49.559 pull and its own unstable orbit. 287 00:14:49.960 --> 00:14:52.360 Okay, so now let's turn to Europa. This is where 288 00:14:52.360 --> 00:14:56.080 the Burn study focuses most powerful calculations. What happens when 289 00:14:56.080 --> 00:14:59.759 you apply that same physics to Europa's position and its 290 00:14:59.759 --> 00:15:00.399 ore bit. 291 00:15:00.799 --> 00:15:03.799 Well, Europa's story is fundamentally different, while it is also 292 00:15:03.919 --> 00:15:07.000 tidally heated. I mean, if it weren't, the ocean wouldn't 293 00:15:07.000 --> 00:15:08.039 be liquid in the first place. 294 00:15:08.120 --> 00:15:09.679 Right, That's a key point. There is some heating. 295 00:15:09.720 --> 00:15:13.039 There is some heating, absolutely, but its orbital parameters are 296 00:15:13.120 --> 00:15:16.679 just far more moderate. For one, Europa is further away 297 00:15:16.679 --> 00:15:20.279 from Jupiter than Io is, and critically, its orbit is 298 00:15:20.399 --> 00:15:22.759 significantly more stable and more circular. 299 00:15:22.879 --> 00:15:26.879 So the stability that makes Europa's journey predictable is paradoxically 300 00:15:27.200 --> 00:15:30.679 the very thing that keeps its internal geological engine from 301 00:15:30.840 --> 00:15:31.519 running hot. 302 00:15:31.679 --> 00:15:34.919 That's the key finding of the study. The gravitational tug 303 00:15:34.919 --> 00:15:38.360 on Europa is much gentler, and it's much more symmetrical 304 00:15:38.399 --> 00:15:42.279 than it is on Io. This gentler poll does cause flexing, 305 00:15:42.559 --> 00:15:45.759 but the crucial differentiation that the Burn team made is 306 00:15:45.799 --> 00:15:48.279 related to the magnitude of that flexing on different parts 307 00:15:48.320 --> 00:15:48.720 of the moon. 308 00:15:49.080 --> 00:15:51.600 Okay, we need to nail this distinction down for the listener. 309 00:15:52.279 --> 00:15:54.960 What part of Europa is getting heated and what part 310 00:15:55.039 --> 00:15:55.759 is staying cold. 311 00:15:56.000 --> 00:15:59.240 So the calculation suggests that the tidal forces are strong 312 00:15:59.320 --> 00:16:02.639 enough to cause significant movement and friction within the outer 313 00:16:02.720 --> 00:16:06.399 ice shell, the ceiling, the ceiling. Yes, this is why 314 00:16:06.440 --> 00:16:10.200 we believe the ice shell is dynamic. It cracks, it refreezes, 315 00:16:10.440 --> 00:16:13.279 it might have plumes shooting out. This flexing in the 316 00:16:13.320 --> 00:16:15.600 ice is what generates enough heat to melt the water 317 00:16:15.679 --> 00:16:18.440 below the ice, and that's what maintains that one hundred 318 00:16:18.480 --> 00:16:19.919 kilometer deep liquid ocean. 319 00:16:20.000 --> 00:16:22.120 So that's the easy part of the equation. The heat 320 00:16:22.240 --> 00:16:23.399 keeps the ocean liquid. 321 00:16:23.519 --> 00:16:26.120 That's the easy part. The tough part is the rocky core, 322 00:16:26.240 --> 00:16:28.679 which is sitting one hundred kilometers beneath the ocean, the 323 00:16:28.759 --> 00:16:32.879 rock water boundary exactly. The calculation suggests that the energy 324 00:16:32.919 --> 00:16:35.639 required to melt a fifteen to twenty five kilometer ice 325 00:16:35.720 --> 00:16:39.759 shell is vastly, vastly less than the energy required to 326 00:16:39.799 --> 00:16:43.600 induce tectonic pleat motion and volcanic activity in a massive, 327 00:16:43.840 --> 00:16:45.120 dense rocky core. 328 00:16:45.320 --> 00:16:47.360 It's just a different physical problem. 329 00:16:46.960 --> 00:16:50.799 A completely different problem. Europe's orbital stability means the differential 330 00:16:50.799 --> 00:16:53.799 stress the squeezing that's applied to the deep rocky core 331 00:16:54.080 --> 00:16:57.639 is minimal. There just isn't enough friction being generated at 332 00:16:57.639 --> 00:17:00.720 that depth to sustain the high temperatures or the convection 333 00:17:00.879 --> 00:17:03.559 currents that you would need to drive seaford geology. 334 00:17:03.720 --> 00:17:07.599 So, in essence, the heat generated by Jupiter's pull is localized. 335 00:17:08.000 --> 00:17:10.480 It's concentrated in the elastic layers, the ice, in the 336 00:17:10.480 --> 00:17:13.480 liquid water, and it just dissipates before it can effectively 337 00:17:13.559 --> 00:17:15.440 fire up the planet's deep internal systems. 338 00:17:15.599 --> 00:17:17.799 Right, the core remains cold and inert. 339 00:17:18.039 --> 00:17:20.279 That is the precise verdict on tidal heating. 340 00:17:20.599 --> 00:17:23.240 It is the forces today are simply not strong enough 341 00:17:23.279 --> 00:17:27.400 to drive any sort of significant active geologic activity at 342 00:17:27.400 --> 00:17:31.359 that rock water boundary. The energy budget for geological activity 343 00:17:31.480 --> 00:17:34.920 is just insufficient. As Burn noted, we don't see any 344 00:17:34.960 --> 00:17:37.079 volcano shooting out of the ice today like we see 345 00:17:37.119 --> 00:17:39.880 on Io, and that's because the engine required to produce 346 00:17:39.920 --> 00:17:43.039 those intense geological events is, for all intents and purposes 347 00:17:43.079 --> 00:17:43.759 switched off. 348 00:17:43.839 --> 00:17:47.960 That is a staggering conclusion and is drawn purely from physics. 349 00:17:48.480 --> 00:17:51.160 So we've established that the residual heat from formation is 350 00:17:51.240 --> 00:17:54.839 long gone and the current dynamic heat source tidal flexing, 351 00:17:55.279 --> 00:17:58.000 is too gentle to reach the core. This leads us 352 00:17:58.039 --> 00:18:01.359 perfectly into the big so wet If the physics tell 353 00:18:01.440 --> 00:18:03.559 us that the sea floor is cold, and silent. What 354 00:18:03.599 --> 00:18:06.799 does a geologically quiet ocean actually mean for life? This 355 00:18:06.839 --> 00:18:08.680 is where we analyze the implication. 356 00:18:08.279 --> 00:18:10.279 And this is where we synthesize the findings and apply 357 00:18:10.319 --> 00:18:13.480 them directly to that core question of habitability. The conclusion 358 00:18:13.519 --> 00:18:17.519 from the Nature Communication study is stark. Europa likely lacks 359 00:18:17.519 --> 00:18:21.079 tectonic motion, It lacks warm hydrothermal vents, and therefore it 360 00:18:21.160 --> 00:18:24.079 lacks the robust cycling mechanisms that are required to create 361 00:18:24.119 --> 00:18:26.000 and sustain a vibrant ecosystem. 362 00:18:26.319 --> 00:18:30.039 It's a vast, dark, cold world at the bottom, despite 363 00:18:30.039 --> 00:18:32.599 the incredible volume of water that's sitting above it. 364 00:18:32.640 --> 00:18:36.039 And if the seafloor is inert, that essential link that's 365 00:18:36.079 --> 00:18:39.519 required to support deep sea life is broken. Let's just 366 00:18:39.559 --> 00:18:43.079 reiterate why that cycling mechanism is so critical. On Earth, 367 00:18:43.240 --> 00:18:46.759 the deep ocean is, for the most part, a chemical. 368 00:18:46.319 --> 00:18:48.599 Desert, right, There's not much going on, not much. 369 00:18:48.440 --> 00:18:53.039 At all, except where geological forces provide a massive concentrated 370 00:18:53.079 --> 00:18:55.240 influx of nutrients and energy from below. 371 00:18:55.680 --> 00:18:59.519 So if Europa lacks those vents, what are the remaining 372 00:18:59.559 --> 00:19:02.759 sources of chemistry available to that one hundred kilometer devotion. 373 00:19:03.079 --> 00:19:05.720 I mean, we have to consider every single possibility, no 374 00:19:05.759 --> 00:19:06.759 matter how remote. 375 00:19:06.960 --> 00:19:09.799 We essentially have two possibilities left, and both of them 376 00:19:09.839 --> 00:19:13.000 are what i'd call low energy options compared to hydrothermal vents. 377 00:19:13.200 --> 00:19:16.599 The first is, as you mentioned earlier, that slow water rock. 378 00:19:16.519 --> 00:19:19.119 Interaction, the trickling background chemistry. 379 00:19:18.720 --> 00:19:21.519 Which is very diffuse and likely way too slow to 380 00:19:21.519 --> 00:19:25.039 support a concentrated food web. And the second possible source 381 00:19:25.319 --> 00:19:27.559 must come from the top, from the ice itself. 382 00:19:27.640 --> 00:19:28.400 Okay, what do you mean. 383 00:19:28.720 --> 00:19:32.160 The surface of Europa is constantly being zapped by Jupiter's 384 00:19:32.200 --> 00:19:36.359 intense radiation field. The Moon is sitting inside these powerful 385 00:19:36.480 --> 00:19:41.079 radiation belts, and this bombardment of energetic particles, it breaks 386 00:19:41.160 --> 00:19:44.279 up water molecules on the surface, and it creates other 387 00:19:44.319 --> 00:19:48.359 compounds right exactly, things like oxygen, hydrogen, peroxide, and various 388 00:19:48.359 --> 00:19:51.640 sulfur compounds. So you have all these chemical oxidants sitting 389 00:19:51.759 --> 00:19:54.799 right there on the surface, essentially frozen into the ice shell. 390 00:19:54.960 --> 00:19:57.240 I see. So the theory is that if the ice 391 00:19:57.240 --> 00:20:00.279 shell is dynamic, if there are cracks, or or if 392 00:20:00.279 --> 00:20:03.920 the ice melts and refreezes a process called convection. 393 00:20:03.799 --> 00:20:07.359 Then these oxidants might eventually be mixed or transported down 394 00:20:07.400 --> 00:20:10.680 into the deep liquid ocean below, and this process, if 395 00:20:10.720 --> 00:20:13.880 it happens efficiently, could provide a different kind of chemical 396 00:20:14.000 --> 00:20:17.079 energy source for life. It could allow organisms to metabolize 397 00:20:17.119 --> 00:20:18.920 the compounds that are supplied from the surface. 398 00:20:19.039 --> 00:20:21.400 But the challenge there, I mean it seems immense too. 399 00:20:21.440 --> 00:20:25.400 You're talking about transporting surface chemicals through a twenty kilometer 400 00:20:25.440 --> 00:20:28.079 thick shield of solid eyes and then through one hundred 401 00:20:28.119 --> 00:20:30.839