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 --> 00:00:26.760 slumber under the night sky. 7 00:00:27.000 --> 00:00:31.800 Picture the most alien inhospitable environments you can possibly imagine. Like, 8 00:00:31.879 --> 00:00:33.640 I want you to close your eyes and really try 9 00:00:33.640 --> 00:00:34.399 to visualize this. 10 00:00:34.520 --> 00:00:36.039 Oh, this is a fun exercise. Go ahead. 11 00:00:36.119 --> 00:00:39.399 Okay, So you're standing on a shoreline, right, But the 12 00:00:39.560 --> 00:00:43.200 liquid that's lapping at your boots it isn't water. It's 13 00:00:43.240 --> 00:00:45.200 a vast lake of liquid methane. 14 00:00:45.320 --> 00:00:45.439 Right. 15 00:00:45.759 --> 00:00:49.159 It's hundreds of degrees below freezing, and it's sitting under 16 00:00:49.200 --> 00:00:52.359 this thick, hazy orange sky that completely blocks out the 17 00:00:52.399 --> 00:00:57.759 sun sound. Or maybe you're suspended in this massive turbulent 18 00:00:57.880 --> 00:01:01.240 cloud layer. You're being whipped around by hurricane force wins 19 00:01:01.479 --> 00:01:04.120 and the mists that's collecting on your suit it's pure 20 00:01:04.280 --> 00:01:05.799 concentrated sulfuric acid. 21 00:01:05.920 --> 00:01:07.680 Wow. Okay, yeah, that's hustle. 22 00:01:07.640 --> 00:01:10.680 Right, Or perhaps you are plunging into the pitch black, 23 00:01:10.719 --> 00:01:13.840 crushing depths of an ocean, locked beneath miles of solid ice, 24 00:01:14.120 --> 00:01:16.799 and literally the only source of heat is the faint 25 00:01:16.879 --> 00:01:18.840 radioactive glow from the planet's core. 26 00:01:18.959 --> 00:01:21.519 Those are some incredibly bleak scenarios, they are. 27 00:01:21.920 --> 00:01:24.519 But here is the massive question for you. What if 28 00:01:24.519 --> 00:01:27.200 I told you that these aren't dead zones? What if 29 00:01:27.239 --> 00:01:32.400 these terrifying, totally extreme landscapes are actually thriving ecosystems. 30 00:01:32.719 --> 00:01:35.920 I mean, it requires a profound shift in perspective. Yes, 31 00:01:36.200 --> 00:01:39.480 it fundamentally challenges how we even define life. 32 00:01:39.159 --> 00:01:44.000 Because right now, literally everything humanity understands about biology is 33 00:01:44.040 --> 00:01:46.280 built on what we know works exactly. 34 00:01:46.599 --> 00:01:49.959 Every textbook you've ever read, every planetary probe we've ever launched, 35 00:01:50.239 --> 00:01:53.640 all our theoretical models for habitable worlds, they're all built 36 00:01:53.680 --> 00:01:56.599 on two completely unshakable. 37 00:01:55.959 --> 00:01:57.719 Pillars, liquid water and oxygen. 38 00:01:58.040 --> 00:02:00.640 Liquid water and oxygen, that is the old standard. 39 00:02:00.719 --> 00:02:03.519 We are entirely obsessed with them. And you know, you 40 00:02:03.599 --> 00:02:06.840 have to wonder, are we suffering from this massive cosmic 41 00:02:06.920 --> 00:02:09.080 case of earth centric bias. 42 00:02:09.240 --> 00:02:10.759 It's a very valid question. 43 00:02:10.719 --> 00:02:14.000 Because the universe is just unimaginably vast and chemically it 44 00:02:14.120 --> 00:02:17.319 is wildly diverse. So today our mission is to embark 45 00:02:17.360 --> 00:02:22.520 on this totally mind bending exploration into alternative biochemistries. 46 00:02:22.759 --> 00:02:25.360 We are basically going to deconstruct the rules of life 47 00:02:25.400 --> 00:02:26.120 as we know them. 48 00:02:26.240 --> 00:02:29.840 Yeah, we'll examine exotic solvents like ammonia and sulfuric acid, 49 00:02:30.120 --> 00:02:33.520 will question the absolute necessity of oxygen, and we'll see 50 00:02:33.560 --> 00:02:36.680 how throwing out the biological rule book completely rewrites our 51 00:02:36.759 --> 00:02:38.400 hunt for extraterrestrial life. 52 00:02:38.479 --> 00:02:41.439 Because, I mean, the laws of physics and chemistry are universal. 53 00:02:42.039 --> 00:02:44.360 A carbon atom behaves the exact same way here on 54 00:02:44.400 --> 00:02:47.199 Earth as it does in the Andromeda galaxy. 55 00:02:47.319 --> 00:02:50.719 Right, the fundamental building blocks are the same everywhere exactly right. 56 00:02:50.759 --> 00:02:54.240 But biology, biology is an emergent property. It's this highly 57 00:02:54.280 --> 00:02:58.879 localized phenomenon that adapts to its specific environment. So to 58 00:02:59.000 --> 00:03:03.879 just assume that biology must always look like Earth biology, well, 59 00:03:04.240 --> 00:03:06.759 it's arguably a bit of a failure of imagination. 60 00:03:07.000 --> 00:03:09.719 So let's unpack this Goldilocks bias we have. Let's start 61 00:03:09.719 --> 00:03:11.960 with the big one, which is water. We constantly hear 62 00:03:12.000 --> 00:03:14.080 it called the universal. 63 00:03:13.639 --> 00:03:15.080 Solvent, right, the magic liquid? 64 00:03:15.319 --> 00:03:18.800 Yeah, and it dictates literally everywhere we point our telescopes. 65 00:03:19.319 --> 00:03:23.439 But what makes it so biologically magical that astrobiologists refuse 66 00:03:23.639 --> 00:03:25.120 to really look for anything else. 67 00:03:25.360 --> 00:03:28.520 Well, water truly is a chemical marvel. Like there are 68 00:03:28.599 --> 00:03:32.560 highly practical structural reasons why we prioritize it so heavily. 69 00:03:32.639 --> 00:03:34.240 It's not just because it's what we drink. 70 00:03:34.360 --> 00:03:36.680 No, not at all. First and foremost, you have to 71 00:03:36.719 --> 00:03:41.080 remember that life is at its core this continuous, highly 72 00:03:41.199 --> 00:03:46.039 choreographed series of chemical reactions. And for those reactions to happen, 73 00:03:46.680 --> 00:03:49.800 you absolutely need a liquid medium. You need a place 74 00:03:49.840 --> 00:03:54.000 where molecules can float around freely, interact and transport materials. 75 00:03:54.120 --> 00:03:56.919 Because if things are solid, they're just they're locked in place, 76 00:03:56.919 --> 00:03:58.199 they can't do anything right. 77 00:03:58.280 --> 00:04:00.479 And if they are a gas, they're way too diffuse 78 00:04:00.520 --> 00:04:01.919 to build any complex structures. 79 00:04:02.400 --> 00:04:04.759 So you need a liquid, a liquid canvas for the 80 00:04:04.800 --> 00:04:05.599 chemistry to happen. 81 00:04:05.680 --> 00:04:09.719 I like that, Yes, a canvas, and water acts as 82 00:04:09.759 --> 00:04:13.840 this incredibly versatile canvas. I mean it remains liquid over 83 00:04:13.879 --> 00:04:17.439 a massive stable temperature range from zero to one hundred 84 00:04:17.480 --> 00:04:20.319 degrees celsius at standard atmospheric. 85 00:04:19.759 --> 00:04:21.480 Pressure, which is a huge window. 86 00:04:21.600 --> 00:04:25.759 It's a massive playground for biology. And furthermore, water molecules 87 00:04:25.759 --> 00:04:26.279 are polar. 88 00:04:26.480 --> 00:04:27.759 Oh right, The polarity. 89 00:04:27.879 --> 00:04:29.680 Yeah, they have a distinct V shape, right, Yeah, with 90 00:04:29.759 --> 00:04:33.720 the oxygen atom pulling electrons slightly toward itself. So this 91 00:04:33.759 --> 00:04:36.680 gives the oxygen and a slight negative charge and the 92 00:04:36.759 --> 00:04:39.040 hydrogen ends a slight positive. 93 00:04:38.639 --> 00:04:41.439 Charge, which makes them act like tiny little magnets. 94 00:04:40.959 --> 00:04:44.519 Exactly, And the polarity allows them to form what we 95 00:04:44.600 --> 00:04:45.920 call hydrogen bonds. 96 00:04:46.240 --> 00:04:50.399 And those hydrogen bonds are like the sticky little connections 97 00:04:50.439 --> 00:04:52.279 that hold biological structures together. 98 00:04:52.439 --> 00:04:55.319 Right, you nailed it. They're weak enough to be broken 99 00:04:55.399 --> 00:04:59.560 and reformed easily, which you absolutely need for dynamic processes 100 00:04:59.560 --> 00:05:04.240 like copy genetic material, but they're strong enough to stabilize massive. 101 00:05:03.920 --> 00:05:05.319 Biomolecules like DNA. 102 00:05:05.519 --> 00:05:08.680 Like DNA, when you look the iconic double helix, it 103 00:05:08.720 --> 00:05:11.680 is held together right down the middle by hydrogen bonds. 104 00:05:11.800 --> 00:05:12.839 That's amazing. 105 00:05:13.160 --> 00:05:16.040 And even the way proteins fold themselves into those complex 106 00:05:16.160 --> 00:05:18.959 three dimensional shapes, which is how they act as the 107 00:05:18.959 --> 00:05:23.240 microscopic machines in our cells, that is entirely dictated by 108 00:05:23.240 --> 00:05:25.639 how they interact with the surrounding water molecules. 109 00:05:25.759 --> 00:05:28.439 Wait, so the water is actually forcing the proteins into 110 00:05:28.439 --> 00:05:29.240 shape exactly. 111 00:05:29.360 --> 00:05:31.360 Some parts of the protein are attracted to water, and 112 00:05:31.439 --> 00:05:33.920 some parts are repelled by it. That push and pull 113 00:05:34.199 --> 00:05:38.160 literally forces the protein to fold into a very specific 114 00:05:38.519 --> 00:05:39.560 functional shape. 115 00:05:39.600 --> 00:05:42.160 So the water isn't just a passive background liquid that 116 00:05:42.199 --> 00:05:45.000 things float in. It is an active structural participant in 117 00:05:45.040 --> 00:05:46.199 the architecture of the cell. 118 00:05:46.480 --> 00:05:50.279 It's the scaffolding, the transportation network, and the climate control 119 00:05:50.319 --> 00:05:52.160 system all rolled into one. 120 00:05:52.399 --> 00:05:54.319 Climate control How does it do that? 121 00:05:54.519 --> 00:05:59.040 Well, water possesses an extraordinarily high heat capacity. That means 122 00:05:59.079 --> 00:06:02.519 it can absorb a massive amount of thermal energy before 123 00:06:02.560 --> 00:06:04.759 its actual temperature rises significantly. 124 00:06:05.000 --> 00:06:07.360 Oh so it buffers against temperature swings. 125 00:06:07.439 --> 00:06:10.720 Right, It buffers our entire planet and the delicate organisms 126 00:06:10.720 --> 00:06:14.759 on it against wild lethal shifts in temperature. A puddle 127 00:06:14.759 --> 00:06:17.639 of water doesn't just boil instantly when the sun hits it. 128 00:06:17.560 --> 00:06:21.120 And the ocean doesn't freeze solid the second winter arrives, exactly. 129 00:06:21.160 --> 00:06:25.360 It facilitates nutrient transport, sweeps away cellular waste, and keeps 130 00:06:25.399 --> 00:06:28.639 the whole system stable. Water is undeniably fantastic. 131 00:06:28.879 --> 00:06:31.920 Five stars for water, absolutely, But you know our current 132 00:06:32.120 --> 00:06:34.920 astrobiology strategy. It feels a bit like that old joke, 133 00:06:35.000 --> 00:06:36.839 which one the one about the guy looking for his 134 00:06:36.959 --> 00:06:40.000 lost keys. Under the street light. Someone asks him, Hey, 135 00:06:40.040 --> 00:06:42.199 did you lose them here? And he says, no, I 136 00:06:42.279 --> 00:06:43.920 lost them over in the dark park. But the light 137 00:06:44.040 --> 00:06:44.920 is better over here. 138 00:06:44.959 --> 00:06:46.920 Ah, yes, the street light effect. 139 00:06:47.279 --> 00:06:49.720 Right. We know how water works, so we only look 140 00:06:49.720 --> 00:06:53.240 for water. But isn't it incredibly arrogant to assume the 141 00:06:53.319 --> 00:06:58.040 rest of the cosmos plays by Earth's very specific chemical rules. 142 00:06:58.600 --> 00:07:00.560 A lot of researchers would agree with you. In fact, 143 00:07:00.600 --> 00:07:03.879 the scientific community literally calls that chemical chauvinism. 144 00:07:04.199 --> 00:07:06.160 Chemical chauvinism. I love that term. 145 00:07:06.199 --> 00:07:09.759 It's very fitting. Many researchers acknowledge this bias, but they 146 00:07:09.879 --> 00:07:13.680 argue it is borne out of strict financial and logistical necessity. 147 00:07:13.240 --> 00:07:17.120 Because space exploration is so staggeringly expensive. 148 00:07:17.279 --> 00:07:21.199 Exactly sending a probe to another planet costs billions of dollars. 149 00:07:21.639 --> 00:07:24.040 If you only have the budget for one single mission, 150 00:07:24.360 --> 00:07:27.319 you send it to the place where you know unequivocally 151 00:07:27.680 --> 00:07:28.720 that the chemistry works. 152 00:07:28.759 --> 00:07:31.160 You bet on the sure thing. Water is a proven concept. 153 00:07:31.360 --> 00:07:31.560 Right. 154 00:07:32.160 --> 00:07:35.040 If we restrict our search strictly to this follo of 155 00:07:35.040 --> 00:07:38.519 the water mantra, however, we do run the massive risk 156 00:07:38.560 --> 00:07:42.240 of being completely blind to entirely different categories of habitable worlds. 157 00:07:42.399 --> 00:07:44.160 So let's say we stuck out of the light of 158 00:07:44.160 --> 00:07:47.160 that earthlike street light. Let's consider that water isn't the 159 00:07:47.160 --> 00:07:51.040 only game in town. What other liquids could potentially act 160 00:07:51.079 --> 00:07:53.360 as the canvas for complex biology. 161 00:07:53.600 --> 00:07:56.000 Well, let's turn down the thermostat. Let's head into the 162 00:07:56.040 --> 00:07:56.800 deep freeze. 163 00:07:56.879 --> 00:07:59.040 Okay, I'm grabbing my coat. Where are we going? 164 00:07:59.120 --> 00:08:02.319 If you move outward in any solar system, away from 165 00:08:02.319 --> 00:08:05.519 the warmth of the host star, water inevitably turns to 166 00:08:05.639 --> 00:08:09.879 solid ice, right, and once it freezes, it becomes useless 167 00:08:10.000 --> 00:08:12.920 as a biological solvent. It essentially just becomes a rock. 168 00:08:13.519 --> 00:08:17.319 But other chemical compounds suddenly become viable liquids at those 169 00:08:17.360 --> 00:08:18.680 extreme negative temperatures. 170 00:08:18.720 --> 00:08:20.240 So what are the top contenders. 171 00:08:20.319 --> 00:08:22.959 Two of the most prominent candidates for alien solvents are 172 00:08:23.000 --> 00:08:25.360 liquid ammonia and liquid hydrocarbons. 173 00:08:25.519 --> 00:08:29.759 Let's look at ammonia first NH three. I mean, on Earth, 174 00:08:29.800 --> 00:08:32.840 we mostly know it as that really pungent chemical in 175 00:08:32.960 --> 00:08:34.519 window cleaners or fertilizer. 176 00:08:34.679 --> 00:08:36.159 Yeah, it has a very distinct smell. 177 00:08:36.360 --> 00:08:40.960 How does a harsh cleaning chemical support a delicate biological ecosystem. 178 00:08:41.480 --> 00:08:44.559 Well, first of all, ammonia is cosmically abundant. It forms 179 00:08:44.600 --> 00:08:47.879 easily in the massive molecular clouds that birth star systems, 180 00:08:48.519 --> 00:08:52.000 but crucially, at standard atmospheric pressure. It exists as a 181 00:08:52.000 --> 00:08:55.200 liquid between negative seventy eight degrees and negative thirty three 182 00:08:55.200 --> 00:08:56.159 degrees celsius. 183 00:08:56.200 --> 00:08:59.559 So it's liquid at very cold temperatures exactly. 184 00:08:59.279 --> 00:09:02.720 And just like water, ammonia molecules are polar. 185 00:09:02.799 --> 00:09:04.360 Oh, so they can do the magnet thing. 186 00:09:04.600 --> 00:09:08.679 Yes, The nitrogen atom pulls electrons away from the hydrogen atoms, 187 00:09:08.840 --> 00:09:13.320 creating a dipole. This means liquid ammonia is highly capable 188 00:09:13.320 --> 00:09:14.720 of forming hydrogen. 189 00:09:14.279 --> 00:09:18.159 Bonds, meaning it could build the scaffolding for cells right. 190 00:09:18.519 --> 00:09:21.960 It can dissolve many organic compounds, meaning it could absolutely 191 00:09:21.960 --> 00:09:24.519 support a rich complex organic chemistry. 192 00:09:24.559 --> 00:09:27.720 But operating at negative seventy eight degrees celsius I mean 193 00:09:27.799 --> 00:09:31.399 that presents a huge thermodynamic hurdle, doesn't it. 194 00:09:31.000 --> 00:09:33.679 It is significantly colder, yes, and ammonia is also a 195 00:09:33.720 --> 00:09:37.000 bit more chemically reactive than water. It has a tendency 196 00:09:37.039 --> 00:09:40.440 to attack and break down certain delicate biomolecules that water 197 00:09:40.480 --> 00:09:41.679 would safely cradle. 198 00:09:41.440 --> 00:09:43.399 So it's a bit of a double edged sword it is. 199 00:09:43.840 --> 00:09:46.919 However, ammonia and water don't have to be mutually exclusive. 200 00:09:47.399 --> 00:09:50.159 In an ammonia water mixture, the ammonia actually acts as 201 00:09:50.200 --> 00:09:51.320 a potent antifreeze. 202 00:09:51.440 --> 00:09:54.919 Oh wow, like in a car radiator, Exactly like that. 203 00:09:55.039 --> 00:09:58.200 It dramatically depresses the freezing point of the mixture. So 204 00:09:58.240 --> 00:10:02.000 you could have subterranean oceans on on icy world's places, 205 00:10:02.399 --> 00:10:07.799 incredibly far outside the traditional habitable zone that remains slushy 206 00:10:07.879 --> 00:10:10.960 and liquid at temperatures that would freeze pure water into 207 00:10:10.960 --> 00:10:11.720 solid granite. 208 00:10:11.919 --> 00:10:14.799 That immediately makes me think of the icy moons further 209 00:10:14.879 --> 00:10:17.039 out in our own solar system. But wait, we can 210 00:10:17.080 --> 00:10:19.720 push the temperature even lower, right you can. Let's talk 211 00:10:19.720 --> 00:10:23.240 about the hydrocarbons on Titan, Saturn's largest moon, Titan is 212 00:10:23.320 --> 00:10:24.000 just wild. 213 00:10:24.120 --> 00:10:28.480 Titan is an absolute astrobiologists stream. It stands as the 214 00:10:28.519 --> 00:10:31.840 only other body in our entire solar system with stable 215 00:10:31.919 --> 00:10:34.440 flowing bodies of liquid right on its surface. 216 00:10:34.559 --> 00:10:36.879 But it is unimaginably cold there. 217 00:10:36.840 --> 00:10:37.360 Very cold. 218 00:10:37.440 --> 00:10:39.960 The surface temperature hovers around negative one hundred and seventy 219 00:10:40.039 --> 00:10:40.759 nine degrees. 220 00:10:40.519 --> 00:10:43.879 Celsius negative one hundred and seventy nine degrees. At that temperature, 221 00:10:43.919 --> 00:10:46.080 water is not a liquid, It's not even a slush. 222 00:10:46.080 --> 00:10:47.799 It is literally a mineral. 223 00:10:47.600 --> 00:10:50.279 Right it forms the actual geological bedrock of the Moon. 224 00:10:50.879 --> 00:10:54.120 Water ice on Titan is as hard at terrestrial granite. 225 00:10:54.159 --> 00:10:55.000 That's crazy, but. 226 00:10:55.000 --> 00:10:58.559 Raining from the sky carving deep branching river valleys into 227 00:10:58.559 --> 00:11:02.480 that ice rock in massive stable lakes and seasier the 228 00:11:02.480 --> 00:11:05.000 poles are liquid hydrocarbons. 229 00:11:05.200 --> 00:11:07.840 Specifically, it's a mixture of methane and ethane, right. 230 00:11:07.720 --> 00:11:11.000 Correct, But here is the massive chemical roadblock with a 231 00:11:11.080 --> 00:11:12.039 hydrocarbon ocean. 232 00:11:12.159 --> 00:11:13.000 Okay, lay it on me. 233 00:11:13.279 --> 00:11:14.080 You remember how. 234 00:11:13.919 --> 00:11:17.320 We just talked about water and ammonia being polar. How 235 00:11:17.320 --> 00:11:20.120 that allows them to do that sticky tape hydrogen bonding 236 00:11:20.159 --> 00:11:22.759 action to fold proteins and build cell membranes. 237 00:11:22.879 --> 00:11:24.679 Yeah, the tiny magnets. 238 00:11:24.440 --> 00:11:27.720 Well, methane and ethane are completely non polar. The electrical 239 00:11:27.759 --> 00:11:31.159 charge is distributed evenly across the whole molecule. They don't 240 00:11:31.200 --> 00:11:33.200 have those charged magnetic ends. 241 00:11:33.279 --> 00:11:36.759 Wait, really, so how do molecules even interact or dissolve 242 00:11:36.799 --> 00:11:38.120 if the liquid isn't polar? 243 00:11:38.440 --> 00:11:39.519 That is the big question. 244 00:11:39.720 --> 00:11:42.480 Wouldn't life at negative one hundred and seventy nine degrees 245 00:11:42.759 --> 00:11:46.200 just freeze and shatter? Like? How do you even build 246 00:11:46.240 --> 00:11:49.879 a functional enclosed cell? In a lake of liquid natural gas. 247 00:11:49.919 --> 00:11:52.240 This is exactly where we have to totally throw out 248 00:11:52.279 --> 00:11:55.039 the Earth biology rule book. Yeah, you cannot just drop 249 00:11:55.039 --> 00:11:56.600 an Earth's cell into liquid methane. 250 00:11:56.639 --> 00:11:58.919 It would just die instantly, instantly. 251 00:11:59.120 --> 00:12:02.840 Our proteins are DNA, our lipid membranes, they all rely 252 00:12:02.960 --> 00:12:06.320 on what we call the hydrophobic effect generated by polar water. 253 00:12:06.960 --> 00:12:10.399 In a non polar solvent like methane, an Earthly cell 254 00:12:10.480 --> 00:12:11.600 membrane wouldn't even. 255 00:12:11.480 --> 00:12:12.279 Hold its shape. 256 00:12:12.399 --> 00:12:13.399 What would happen to it? 257 00:12:13.399 --> 00:12:16.240 It would essentially turn inside out or its components would 258 00:12:16.279 --> 00:12:18.440 just dissolve and disperse completely into the liquid. 259 00:12:18.600 --> 00:12:21.879 Oh, because lipids on Earth have a water loving head 260 00:12:21.960 --> 00:12:25.840 and a water hating tail, right, and they arrange themselves 261 00:12:25.840 --> 00:12:29.559 into a sphere specifically to hide the tails from. 262 00:12:29.320 --> 00:12:30.879 The water a perfect description. 263 00:12:31.039 --> 00:12:33.679 So in methane there's no water to hide from, so 264 00:12:33.799 --> 00:12:35.120 the sphere just falls apart. 265 00:12:35.240 --> 00:12:39.559 Precisely so, life in a non polar hydrocarbon ocean would 266 00:12:39.639 --> 00:12:42.200 need completely different structural scaffolding. 267 00:12:42.360 --> 00:12:43.360 What would that even look like? 268 00:12:43.600 --> 00:12:46.639 Instead of relying on our familiar proteins and amino acids, 269 00:12:47.000 --> 00:12:49.759 a tight native might build its cellular structures out of 270 00:12:49.799 --> 00:12:55.000 long chain hydrocarbons or highly specialized nitrogen bearing molecules molecules 271 00:12:55.000 --> 00:12:58.039 that naturally assemble into membranes in a non polar environment 272 00:12:58.200 --> 00:13:01.679 that is wild, and they would use water soluble sugars 273 00:13:01.679 --> 00:13:05.399 for energy either, they would likely utilize the abundant organic 274 00:13:05.480 --> 00:13:10.720 compounds that are constantly raining down from Titan's thick, photochemically 275 00:13:10.720 --> 00:13:11.679 active atmosphere. 276 00:13:11.759 --> 00:13:13.720 Okay, but the temperature is still the elephant in the 277 00:13:13.799 --> 00:13:17.120 room here negative one hundred and seventy nine degrees celsius. 278 00:13:17.200 --> 00:13:19.759 Yes, thermodynamics is a strict master. 279 00:13:19.759 --> 00:13:22.240 Because everything slows down when it's cold. I mean, we 280 00:13:22.279 --> 00:13:25.679 put food in the freezer specifically to stop chemical reactions 281 00:13:25.679 --> 00:13:29.320 from making it go bad. So how does a biological 282 00:13:29.480 --> 00:13:32.919 entity actually do anything at a temperature where chemistry practically 283 00:13:33.000 --> 00:13:33.960 grinds to a halt. 284 00:13:34.200 --> 00:13:36.399 This is where we have to introduce the concept of 285 00:13:36.759 --> 00:13:42.519 slower time. Chemical reaction rates are deeply mathematically dependent on temperature. 286 00:13:42.960 --> 00:13:46.720 As you lower the ambient heat, molecules possess less kinetic energy, 287 00:13:46.879 --> 00:13:49.759 They jiggle less, they bump into each other much less frequently, 288 00:13:50.120 --> 00:13:52.840 and the energy available to break and form new chemical 289 00:13:52.879 --> 00:13:55.240 bonds drops off a massive cliff. 290 00:13:55.480 --> 00:13:59.159 So their entire existence would be operating on this radically 291 00:13:59.200 --> 00:14:01.440 stretched temper scale exactly. 292 00:14:01.840 --> 00:14:06.679 Life in liquid methane would be profoundly slow metabolizing. If 293 00:14:06.720 --> 00:14:09.600 we think of a typical metabolic chemical reaction in an 294 00:14:09.600 --> 00:14:12.279 Earth cell, taking say a fraction. 295 00:14:11.879 --> 00:14:14.200 Of a second, which happens constantly, right. 296 00:14:14.240 --> 00:14:16.120 An equivalent biological. 297 00:14:18.159 --> 00:14:23.120 A longer complete wait, So an organism's lifespan, it's cellular reproduction, 298 00:14:23.399 --> 00:14:26.559 it's physical movement across the seabed, it would all be 299 00:14:26.759 --> 00:14:29.039 agonizingly stretched out absolutely. 300 00:14:29.519 --> 00:14:33.960 Observing a Titan ecosystem with human eyes might look completely static. 301 00:14:34.200 --> 00:14:37.399 It might just look like a frozen tableau or a landscape. 302 00:14:36.919 --> 00:14:38.840 Of rock, like nothing is happening at all. 303 00:14:38.919 --> 00:14:41.080 Right, But if you set up a time lapse camera 304 00:14:41.159 --> 00:14:44.519 and watched it over decades or centuries, only then would 305 00:14:44.519 --> 00:14:48.720 you see organisms slowly moving, feeding, exchanging chemicals and dividing. 306 00:14:48.879 --> 00:14:50.080 That is so eerie. 307 00:14:50.200 --> 00:14:53.399 Because the thermal energy available is so incredibly low, absolute 308 00:14:53.480 --> 00:14:58.360 metabolic efficiency and extreme patients become the primary driving evolutionary forces. 309 00:14:58.559 --> 00:15:02.399 Picturing Titan's landscape through this lens is just haunting. You 310 00:15:02.440 --> 00:15:07.279 have a hazy sky raining liquid methane rivers actively carving 311 00:15:07.360 --> 00:15:10.840 canyons into water ice bedrock, and the potential for a 312 00:15:10.960 --> 00:15:16.399 slow motion, non polar ecosystem operating completely invisibly beneath our 313 00:15:16.399 --> 00:15:17.759 current planetary probes. 314 00:15:17.799 --> 00:15:18.679 It's very possible. 315 00:15:18.799 --> 00:15:21.759 I mean, when the Cassini Huygens mission dropped a probe 316 00:15:21.759 --> 00:15:24.399 through Titan's atmosphere back in two thousand and five, it 317 00:15:24.480 --> 00:15:28.399 landed on a damp floodplaine and photographed these rounded, smooth 318 00:15:28.519 --> 00:15:29.360 ice cobbles. 319 00:15:29.600 --> 00:15:30.840 I remember those images. 320 00:15:30.919 --> 00:15:32.919 What if there was a biosphere right there in front 321 00:15:32.960 --> 00:15:35.720 of the lens, But its metabolism is so slow and 322 00:15:35.759 --> 00:15:39.000 its chemistry is so radically non polar that our sensors 323 00:15:39.080 --> 00:15:42.159 just interpreted it as complex carbon rich dirt. 324 00:15:42.399 --> 00:15:44.960 It is entirely within the realm of possibility. We wouldn't 325 00:15:44.960 --> 00:15:47.679 even recognize it as life. And while methane and ethane 326 00:15:47.679 --> 00:15:50.279 are the obvious stars of the show on Titan, chemists 327 00:15:50.279 --> 00:15:53.440 have modeled other exotic alternative solvents for extreme cold or 328 00:15:53.519 --> 00:15:57.039 high pressure conditions too. Oh like what else compounds like formamide, 329 00:15:57.159 --> 00:16:00.679 hydrogen fluoride, or even certain liquid salts that remains stable 330 00:16:00.720 --> 00:16:03.399 and fluid in environments where water would just instantly boil 331 00:16:03.480 --> 00:16:04.360 or freeze solid. 332 00:16:04.759 --> 00:16:06.879 The options are wider than we think exactly. 333 00:16:07.000 --> 00:16:09.799 The overarching point is that the liquid canvas for biology 334 00:16:10.120 --> 00:16:11.240 doesn't strictly have to. 335 00:16:11.200 --> 00:16:11.879 Be h two zero. 336 00:16:12.200 --> 00:16:16.080 Well, if extreme cold forces life to stretch time to 337 00:16:16.080 --> 00:16:19.000 solve the energy problem, it makes me wonder how life 338 00:16:19.039 --> 00:16:23.600 solves the opposite problem, touch energy exactly? What about environments 339 00:16:23.600 --> 00:16:26.919 with far too much violent energy, places where the heat 340 00:16:26.960 --> 00:16:30.200 and the aggressive chemistry are actively trying to tear complex 341 00:16:30.240 --> 00:16:33.480 molecules apart. Let's look at the ultimate acid. 342 00:16:33.200 --> 00:16:35.360 Test ah sulfuric acil. 343 00:16:35.039 --> 00:16:38.559 Furic acid, which brings us directly to Venus. Venus is 344 00:16:38.600 --> 00:16:41.159 frequently called Earth's evil twin right. 345 00:16:41.399 --> 00:16:45.120 Very evil. Its rocky surface is a literal hellscape. Temperatures 346 00:16:45.159 --> 00:16:47.600 are around four hundred and seventy degrees celsius, and it 347 00:16:47.639 --> 00:16:51.159 has a crushing atmospheric pressure roughly ninety times out of Earth. 348 00:16:51.320 --> 00:16:52.919 So nothing is surviving down there. 349 00:16:53.039 --> 00:16:55.759 No, the surface is basically a dead end for biology 350 00:16:55.759 --> 00:16:58.360 as we understand it. But if you ascend about fifty 351 00:16:58.399 --> 00:17:01.799 kilometers up into the Venusian atmosphe the temperature and pressure 352 00:17:01.840 --> 00:17:05.319 are surprisingly earth like. They hover right around room temperature. 353 00:17:05.319 --> 00:17:07.000 Oh really, that sounds quite pleasant. 354 00:17:07.200 --> 00:17:10.000 Well, don't pack your bags just yet. The major catch 355 00:17:10.119 --> 00:17:12.920 is the composition of the clouds. They are made of 356 00:17:13.079 --> 00:17:17.720 highly concentrated liquid sulfuric acid droplets. 357 00:17:17.319 --> 00:17:21.079 Which is terrifying to even conceptualize. Sulfuric acid eats through 358 00:17:21.119 --> 00:17:24.519 solid metal. It does if you expose organic matter to 359 00:17:24.680 --> 00:17:27.160 it's a piece of water, a piece of meat, It 360 00:17:27.240 --> 00:17:31.640 turns black, violently boils, and just dissolves into sludge. It 361 00:17:31.720 --> 00:17:34.960 is so hard to imagine how that environment could host life. 362 00:17:35.160 --> 00:17:37.519 I used to picture it like trying to build a delicate, 363 00:17:37.599 --> 00:17:40.519 intricate house of cards while inside a wind tunnel. 364 00:17:40.559 --> 00:17:43.079 That's a great visual, But it's not a kinetic destruction, 365 00:17:43.200 --> 00:17:45.039 is it. It's a chemical destruction, right. 366 00:17:45.160 --> 00:17:48.160 That distinction is crucial. It seems impossible to us because 367 00:17:48.319 --> 00:17:51.519 our biology is fundamentally built on carbon water chemistry. 368 00:17:51.680 --> 00:17:52.160 Exactly. 369 00:17:52.400 --> 00:17:55.680 We have to understand why sulfuric acid destroys earth life 370 00:17:55.799 --> 00:17:56.559 so violently. 371 00:17:56.640 --> 00:17:57.759 Okay, break it down for me. 372 00:17:57.920 --> 00:18:02.759 Sulfuric acid is intensely hygrosspic meaning it is incredibly greedy 373 00:18:02.759 --> 00:18:05.720 for water. It doesn't just dissolve the physical structure, It 374 00:18:05.880 --> 00:18:09.279 actively rips the hydrogen and oxygen atoms right out of 375 00:18:09.319 --> 00:18:12.480 the molecular structure of carbohydrates and proteins. Just to form 376 00:18:12.519 --> 00:18:13.440 water for itself. 377 00:18:13.759 --> 00:18:16.599 Oh wow, so it's stealing the water from the cells. 378 00:18:16.279 --> 00:18:20.000 Precisely that black sledge left behind. That is just the 379 00:18:20.079 --> 00:18:23.319 dead carbon skeleton that remains after the water has been 380 00:18:23.400 --> 00:18:24.240 chemically stolen. 381 00:18:24.400 --> 00:18:27.559 So it's not that the acid is fundamentally anti life, 382 00:18:27.680 --> 00:18:30.880 it's just specifically anti water based life. 383 00:18:31.000 --> 00:18:33.839 You hit the nail on the head. An organism native 384 00:18:33.880 --> 00:18:37.279 to a sulfuric acid environment wouldn't be fighting the acid, 385 00:18:37.640 --> 00:18:41.160 it would be utilizing it as its primary solvent instead 386 00:18:41.160 --> 00:18:45.000 of water exactly. Sulfuric acid is actually a fantastic solvent 387 00:18:45.039 --> 00:18:48.119 in its own right. It remains liquid over an enormous 388 00:18:48.119 --> 00:18:53.400 temperature range, much larger than water. Furthermore, it forms incredibly strong, 389 00:18:53.640 --> 00:18:56.680 complex hydrogen bonding networks. 390 00:18:56.240 --> 00:18:59.319 So it operates on similar chemical principles to water. 391 00:18:59.519 --> 00:19:02.400 Yes, you still get that sticky scaffolding that allows for 392 00:19:02.480 --> 00:19:06.519 complex three dimensional biological structures to fold and hold their shape. 393 00:19:06.119 --> 00:19:09.039 But the molecular building blocks would have to be entirely different. 394 00:19:08.799 --> 00:19:12.039 Right, Oh completely. A Venusia microbe floating in those clouds 395 00:19:12.119 --> 00:19:15.640 wouldn't use our specific DNA or proteins because the acid 396 00:19:15.640 --> 00:19:17.400 would immediately dehydrate. 397 00:19:16.920 --> 00:19:18.920 And shred them right, It would turn them to sludge. 398 00:19:19.119 --> 00:19:23.519 It would use entirely different acid stable polymers for its 399 00:19:23.599 --> 00:19:27.720 genetics and its internal catalysis. It would build its cellular 400 00:19:27.799 --> 00:19:31.839 machinery out of molecules that are highly resistant to being 401 00:19:31.880 --> 00:19:35.960