1 00:00:08,480 --> 00:00:10,880 Speaker 1: Hey, or hey, are you ready to dig into another 2 00:00:11,039 --> 00:00:15,720 Speaker 1: controversial topic? Who did you take some classified physics documents 3 00:00:15,720 --> 00:00:19,840 Speaker 1: to your house or something? Oh? They don't let me 4 00:00:19,840 --> 00:00:21,720 Speaker 1: see any of that stuff. But this is much more 5 00:00:21,760 --> 00:00:25,439 Speaker 1: important than that. I'm wondering where you land on the 6 00:00:25,480 --> 00:00:29,000 Speaker 1: debate about bread? Do you prefer it light and fluffy 7 00:00:29,240 --> 00:00:32,400 Speaker 1: or dark and heavy? Oh? I didn't even know there 8 00:00:32,479 --> 00:00:35,640 Speaker 1: was a debate about bread. Mostly I just eat it. 9 00:00:35,720 --> 00:00:38,720 Speaker 1: I mean, if people argue about like chocolate versus vanilla 10 00:00:38,800 --> 00:00:41,440 Speaker 1: ice cream, you know they're going to argue about French 11 00:00:41,479 --> 00:00:45,080 Speaker 1: baguettes versus German RYE. Well, it kind of depends on 12 00:00:45,120 --> 00:00:47,680 Speaker 1: how hungry you are. If you're hungry, you'll eat any bread. 13 00:00:47,760 --> 00:00:49,640 Speaker 1: But isn't that more of a cultural topic than a 14 00:00:49,680 --> 00:00:52,280 Speaker 1: physics topic. It's a cultural topic, but it's also a 15 00:00:52,320 --> 00:00:55,040 Speaker 1: physics topic because it's all about density. Do you like 16 00:00:55,080 --> 00:00:57,280 Speaker 1: bread that floats or sinks when you drop it in 17 00:00:57,320 --> 00:00:59,680 Speaker 1: the pool? It sounds like you've done this experiment. It's 18 00:00:59,720 --> 00:01:02,080 Speaker 1: an the mental question about every object in your life? 19 00:01:02,200 --> 00:01:06,880 Speaker 1: Will it float? Returned this on your children as well? Yes, 20 00:01:06,959 --> 00:01:09,280 Speaker 1: and I can confirm that my children do float, and 21 00:01:09,319 --> 00:01:11,840 Speaker 1: are they den only in the best way? Possible. Well, 22 00:01:11,840 --> 00:01:13,920 Speaker 1: in terms of bread, I'd rather you don't throw it 23 00:01:13,920 --> 00:01:16,480 Speaker 1: into a pool. I'm not sure I like my bread soggy. 24 00:01:16,720 --> 00:01:19,200 Speaker 1: I'm sure there's someone out there who disagrees with you. 25 00:01:19,440 --> 00:01:22,120 Speaker 1: That will be a very dense debate. I'm sure I'll 26 00:01:22,240 --> 00:01:40,080 Speaker 1: rise to the occasion. Hi am or Hid, my cartoonists 27 00:01:40,080 --> 00:01:43,560 Speaker 1: and the co author of Frequently Asked Questions about the Universe. Hi, 28 00:01:43,720 --> 00:01:46,560 Speaker 1: I'm Daniel. I'm a particle physicist and a professor at 29 00:01:46,600 --> 00:01:49,920 Speaker 1: U c Irvine, and I really miss Dave Letterman's bit 30 00:01:50,120 --> 00:01:53,000 Speaker 1: called will It Float? Oh? Is that the one where 31 00:01:53,000 --> 00:01:55,000 Speaker 1: he makes things float? Or is that the one where 32 00:01:55,000 --> 00:01:56,720 Speaker 1: he throws things out of the roof? I love that 33 00:01:56,720 --> 00:01:59,000 Speaker 1: he did so many physics experiments, but one of my 34 00:01:59,040 --> 00:02:01,280 Speaker 1: favorites was will Float, where he just brings out a 35 00:02:01,320 --> 00:02:03,760 Speaker 1: tub of water and random stuff and he asks the 36 00:02:03,800 --> 00:02:05,840 Speaker 1: audience do you think it's going to float? And then 37 00:02:05,840 --> 00:02:07,680 Speaker 1: of course he throws it in the pool and they 38 00:02:07,760 --> 00:02:11,600 Speaker 1: find out it's pure physics, right right? Yeah? What kinds 39 00:02:11,600 --> 00:02:13,519 Speaker 1: of things would he test? Well, you know, we had 40 00:02:13,560 --> 00:02:18,799 Speaker 1: bowling balls and chainsaws, but also you know, loaves of bread, pumpkins, 41 00:02:19,040 --> 00:02:21,120 Speaker 1: all sorts of things sort of right, on the edge 42 00:02:21,240 --> 00:02:25,040 Speaker 1: that divided people and tested their intuition. I feel like 43 00:02:25,040 --> 00:02:28,119 Speaker 1: it's also kind of an engineering question, like how watertight 44 00:02:28,200 --> 00:02:31,400 Speaker 1: something is, because if something could be light and float, 45 00:02:31,800 --> 00:02:34,680 Speaker 1: but eventually you'll think, yeah, that's true, like a paper 46 00:02:34,680 --> 00:02:37,959 Speaker 1: boat will float initially until it gets water logged. Yeah, 47 00:02:38,000 --> 00:02:40,280 Speaker 1: it's all about engineering at the end, truly the most 48 00:02:40,280 --> 00:02:43,120 Speaker 1: important discipline. But anyways, welcome to a podcast Daniel and 49 00:02:43,160 --> 00:02:46,120 Speaker 1: Jorge Explain the Universe, a production of I Heart Radio, 50 00:02:46,240 --> 00:02:50,680 Speaker 1: in which we float various ideas about how the universe works, 51 00:02:50,760 --> 00:02:53,160 Speaker 1: how it all comes together, what is made out of 52 00:02:53,160 --> 00:02:56,079 Speaker 1: at its smallest bits, and how those bits to and 53 00:02:56,120 --> 00:02:58,960 Speaker 1: fro and zip back and forth and buzz together to 54 00:02:59,080 --> 00:03:01,840 Speaker 1: make the universe that we are familiar with, the one 55 00:03:01,880 --> 00:03:05,919 Speaker 1: that we experience, the one we are so curious to understand. 56 00:03:06,080 --> 00:03:08,800 Speaker 1: We dig deep into all the questions about the basic 57 00:03:08,919 --> 00:03:12,160 Speaker 1: nature of reality and how everything behaves and try to 58 00:03:12,200 --> 00:03:14,640 Speaker 1: explain all of it to you. That's right, because it 59 00:03:14,760 --> 00:03:17,840 Speaker 1: is a pretty dense universe, pack full of interesting and 60 00:03:17,880 --> 00:03:20,800 Speaker 1: amazing facts and phenomena to discover and to explore, and 61 00:03:20,840 --> 00:03:22,760 Speaker 1: we like to make it all light and fluffy for 62 00:03:22,880 --> 00:03:25,600 Speaker 1: you here on the podcast. And I guess you know. 63 00:03:25,639 --> 00:03:27,799 Speaker 1: I was just googling will It Float and discovered that 64 00:03:27,880 --> 00:03:31,520 Speaker 1: Letterman once released an Xbox version of Will It Float? 65 00:03:31,520 --> 00:03:35,400 Speaker 1: What like, will it Xbox float or sink? Or can 66 00:03:35,440 --> 00:03:38,320 Speaker 1: you play inside the Xbox? That is a good question, 67 00:03:38,320 --> 00:03:41,800 Speaker 1: whether an Xbox will float or sink? Probably it'll sink, 68 00:03:42,040 --> 00:03:43,440 Speaker 1: but no, he had a version of it, which was 69 00:03:43,480 --> 00:03:46,280 Speaker 1: a game you can play on the Xbox, like you 70 00:03:46,360 --> 00:03:48,960 Speaker 1: predict whether various things are going to float or sink, 71 00:03:49,040 --> 00:03:51,360 Speaker 1: and then they dump them in a virtual tub. I 72 00:03:51,400 --> 00:03:54,040 Speaker 1: feel like that's a little bit of an overkill for 73 00:03:54,200 --> 00:03:56,960 Speaker 1: the Xbox's abilities here. I think maybe he was just 74 00:03:57,000 --> 00:04:00,760 Speaker 1: playing a joke about merchandizing and commercialization of stuff. How 75 00:04:00,800 --> 00:04:02,839 Speaker 1: would your son feel if you throw his Xbox into 76 00:04:02,880 --> 00:04:05,400 Speaker 1: a tub of water? He would probably jump in afterwards, 77 00:04:05,440 --> 00:04:07,520 Speaker 1: and then I would learn whether it floated and whether 78 00:04:07,560 --> 00:04:09,520 Speaker 1: he floated at the same time, What did you throw 79 00:04:09,600 --> 00:04:12,800 Speaker 1: both in? You only need to throw one in and 80 00:04:12,840 --> 00:04:14,800 Speaker 1: then he jumps in after it, So as long as 81 00:04:14,800 --> 00:04:17,200 Speaker 1: it's not still connected to the plug in the wall, 82 00:04:17,760 --> 00:04:20,080 Speaker 1: it's not a bad exercise. But as much as we 83 00:04:20,160 --> 00:04:22,400 Speaker 1: like to joke about whether things float, it's part of 84 00:04:22,480 --> 00:04:25,680 Speaker 1: just wondering how things work and what's inside of them. 85 00:04:25,800 --> 00:04:28,839 Speaker 1: There's a long history of dunking things in water to 86 00:04:29,080 --> 00:04:31,480 Speaker 1: understand them, all the way back to measuring the volume 87 00:04:31,520 --> 00:04:34,279 Speaker 1: of things by immersing them in a bathtub. Yeah. And 88 00:04:34,400 --> 00:04:38,279 Speaker 1: as you know, whether something floats or doesn't float, it 89 00:04:38,320 --> 00:04:40,919 Speaker 1: has everything to do with its density. If something is 90 00:04:41,000 --> 00:04:43,839 Speaker 1: denser than water, then it's going to think. If it's 91 00:04:43,920 --> 00:04:46,080 Speaker 1: less dense than water, it's going to float in the 92 00:04:46,160 --> 00:04:49,719 Speaker 1: universe has all kinds of densities in its existence, that's right. 93 00:04:49,800 --> 00:04:52,480 Speaker 1: And people have all kinds of densities in their bodies 94 00:04:52,520 --> 00:04:55,159 Speaker 1: and stuff around us has all sorts of densities, which 95 00:04:55,160 --> 00:04:57,839 Speaker 1: is why people have been building boats out of wood 96 00:04:57,920 --> 00:05:00,800 Speaker 1: and not out of stone for thousands of years. You 97 00:05:00,839 --> 00:05:02,719 Speaker 1: can make a stone boat, right, You could make a 98 00:05:02,760 --> 00:05:05,080 Speaker 1: stone boat if it had a big air pocket in it, right, 99 00:05:05,400 --> 00:05:08,200 Speaker 1: That's how those ships are made of steel. Steel obviously 100 00:05:08,320 --> 00:05:11,560 Speaker 1: much denser than water, but a modern steel ship has 101 00:05:11,560 --> 00:05:14,040 Speaker 1: a huge pocket of air inside it, like a big 102 00:05:14,040 --> 00:05:18,040 Speaker 1: steel balloon essentially. Yeah. And actually, if you studies civil engineering, 103 00:05:18,040 --> 00:05:19,880 Speaker 1: a big rite of passage and a lot of schools 104 00:05:19,960 --> 00:05:22,719 Speaker 1: is to make a concrete boat, is that right? So 105 00:05:22,720 --> 00:05:26,080 Speaker 1: that's something people really do Yeah, that's awesome. Well, I 106 00:05:26,120 --> 00:05:28,720 Speaker 1: wonder what the densest material you can make a boat 107 00:05:28,720 --> 00:05:31,520 Speaker 1: out of is. Can you make a neutron star boat 108 00:05:34,080 --> 00:05:37,440 Speaker 1: nuclear pasta boat? You can use sheets of nuclear lasagna? 109 00:05:37,480 --> 00:05:40,120 Speaker 1: I suppose, Yeah, I guess it would collapse the entire planet. 110 00:05:40,160 --> 00:05:42,000 Speaker 1: But you know, at least he would test that theory. 111 00:05:42,080 --> 00:05:45,000 Speaker 1: You'd win that engineering competition along the way. And for 112 00:05:45,040 --> 00:05:47,440 Speaker 1: those of you out there confused about why things that 113 00:05:47,520 --> 00:05:50,000 Speaker 1: are denser than water can float, the key is not 114 00:05:50,080 --> 00:05:53,600 Speaker 1: the density of the container necessarily, but the overall average 115 00:05:53,640 --> 00:05:56,200 Speaker 1: density of the object. So if you make a big 116 00:05:56,240 --> 00:05:59,480 Speaker 1: balloon out of neutron star material, as long as it's 117 00:05:59,560 --> 00:06:02,680 Speaker 1: enough air are inside of it, the average density is 118 00:06:02,760 --> 00:06:05,320 Speaker 1: less than the density of water, and then it can float. Yeah, 119 00:06:05,360 --> 00:06:07,400 Speaker 1: And so the universe has all kinds of dense things. 120 00:06:07,400 --> 00:06:10,120 Speaker 1: We've talked on this podcast about neutron stars, which are 121 00:06:10,160 --> 00:06:12,400 Speaker 1: some of the densest things in the universe, and we've 122 00:06:12,440 --> 00:06:15,240 Speaker 1: also talked about the opposite, which is the emptiest spots 123 00:06:15,240 --> 00:06:17,599 Speaker 1: in the universe as well. The extremes are really fun 124 00:06:17,640 --> 00:06:19,800 Speaker 1: places to think about because they show us what the 125 00:06:19,920 --> 00:06:23,320 Speaker 1: edge cases are, what the rules are, what it's possible 126 00:06:23,360 --> 00:06:26,240 Speaker 1: to achieve, and they also illuminate how various forces in 127 00:06:26,360 --> 00:06:31,040 Speaker 1: various factors come together to achieve such densities or such emptiness. 128 00:06:31,120 --> 00:06:34,760 Speaker 1: Is so understanding how things can get really, really dense 129 00:06:35,000 --> 00:06:37,760 Speaker 1: can give us some understanding about how things work. Yeah, 130 00:06:37,800 --> 00:06:39,880 Speaker 1: they are all kinds of forces and universe. A lot 131 00:06:39,920 --> 00:06:42,680 Speaker 1: of them are pushing things together, like gravity or the 132 00:06:42,839 --> 00:06:45,520 Speaker 1: strong nuclear force, and a lot of things are also 133 00:06:45,560 --> 00:06:49,040 Speaker 1: pushing things apart, like the electromagnetic force. Density plays an 134 00:06:49,040 --> 00:06:52,040 Speaker 1: important role in the heart of our Sun, allowing us 135 00:06:52,040 --> 00:06:55,599 Speaker 1: to warm our toes on that incredible cosmic fire even 136 00:06:55,640 --> 00:06:59,320 Speaker 1: though it's millions and millions of miles away. It's density 137 00:06:59,400 --> 00:07:02,880 Speaker 1: that creates the conditions necessary for fusion at the heart 138 00:07:02,920 --> 00:07:05,200 Speaker 1: of our star, and it plays a big role in 139 00:07:05,200 --> 00:07:08,360 Speaker 1: our solar system. I guess, especially here on Earth right 140 00:07:08,400 --> 00:07:10,720 Speaker 1: if Earth was less dense than it was, it would 141 00:07:10,720 --> 00:07:14,320 Speaker 1: probably what collapse or float away? Well, I think what's 142 00:07:14,320 --> 00:07:17,160 Speaker 1: interesting is to ask how dense is Earth and why 143 00:07:17,320 --> 00:07:19,320 Speaker 1: is it that dense? And then to look around to 144 00:07:19,360 --> 00:07:21,880 Speaker 1: the other planets and when they're like are they more dense? 145 00:07:21,920 --> 00:07:24,880 Speaker 1: Are they less dense? What's going on? It's part of 146 00:07:25,040 --> 00:07:27,920 Speaker 1: understanding how our solar system came to be the way 147 00:07:27,960 --> 00:07:31,960 Speaker 1: that it is, and understanding whether it's unusual because our 148 00:07:32,000 --> 00:07:34,840 Speaker 1: solar system weird compared to other solar systems. Are other 149 00:07:34,920 --> 00:07:38,160 Speaker 1: planets out there more massive, more dense? Are they fluffier 150 00:07:38,200 --> 00:07:40,920 Speaker 1: than a French baguette? Are they denser than German rye? 151 00:07:41,160 --> 00:07:43,440 Speaker 1: So today on the podcast, we'll be asking the question 152 00:07:48,520 --> 00:07:52,080 Speaker 1: what is the densest planet? Now? My first question to you, 153 00:07:52,160 --> 00:07:54,000 Speaker 1: Jorge is do you think this is something to be 154 00:07:54,080 --> 00:07:56,920 Speaker 1: proud of or something to be embarrassed about? Which one? 155 00:07:57,040 --> 00:07:59,920 Speaker 1: What do you mean like asking questions or eating bread? 156 00:08:01,320 --> 00:08:03,800 Speaker 1: If we're gonna label one planet as densest, do you 157 00:08:03,840 --> 00:08:06,440 Speaker 1: think that's something the denizens of that planet should be 158 00:08:06,440 --> 00:08:10,200 Speaker 1: proud of or embarrassed by. Yes, I was going to 159 00:08:10,320 --> 00:08:12,520 Speaker 1: ask you that you thought this was an appropriate question 160 00:08:12,560 --> 00:08:14,880 Speaker 1: to ask. I guess it depends. First of all, if 161 00:08:14,880 --> 00:08:18,920 Speaker 1: there are people another planets, that's amazing, But also I 162 00:08:18,920 --> 00:08:21,400 Speaker 1: guess if you're talking about their planet, then they wouldn't 163 00:08:21,440 --> 00:08:24,800 Speaker 1: necessarily be offended. Yeah, dense has some interesting connotations. Right, 164 00:08:24,880 --> 00:08:27,480 Speaker 1: No person would want to be called dance because it 165 00:08:27,480 --> 00:08:30,680 Speaker 1: applies that you're not very smart unless you're dense with 166 00:08:30,720 --> 00:08:36,760 Speaker 1: awesomeness jam packed with jam packed with wonderfulness, dense with talent. 167 00:08:39,679 --> 00:08:41,360 Speaker 1: On the other hand, if you're talking about a planet, 168 00:08:41,400 --> 00:08:44,600 Speaker 1: maybe it means that you're filled with diamonds and gold 169 00:08:44,679 --> 00:08:47,319 Speaker 1: and all sorts of valuable heavy metals. Right, A huge 170 00:08:47,320 --> 00:08:50,480 Speaker 1: blob of platinum is pretty dense, and I'd rather take 171 00:08:50,520 --> 00:08:53,600 Speaker 1: that than a blob of water to drink, you mean 172 00:08:53,640 --> 00:08:55,959 Speaker 1: to drink or to flirt it. No, when they're like 173 00:08:56,000 --> 00:08:58,800 Speaker 1: assigning mineral rights in the Solar System, you know, I'll 174 00:08:58,800 --> 00:09:02,640 Speaker 1: take the denser asteroid, please, thank you very much, because 175 00:09:02,720 --> 00:09:05,400 Speaker 1: then you can do what with it. You can't live 176 00:09:05,400 --> 00:09:07,360 Speaker 1: in it if there's no water in it, No, you 177 00:09:07,360 --> 00:09:08,640 Speaker 1: can't live in it. There's no water in it. But 178 00:09:08,679 --> 00:09:10,800 Speaker 1: there's plenty of water out there in the Solar System. 179 00:09:10,840 --> 00:09:12,960 Speaker 1: But you know, some of those asteroids are just like 180 00:09:13,160 --> 00:09:16,679 Speaker 1: huge blobs of platinum or other rare earth metals that 181 00:09:16,720 --> 00:09:19,080 Speaker 1: we need here on Earth to make batteries for all 182 00:09:19,120 --> 00:09:21,920 Speaker 1: of our fancy gizmos. Yeah. So there's a huge range 183 00:09:22,040 --> 00:09:25,200 Speaker 1: of density in our Solar System that I guess you 184 00:09:25,240 --> 00:09:27,800 Speaker 1: can go from planets that are made out entirely out 185 00:09:27,800 --> 00:09:30,560 Speaker 1: of gas, which is gas, and then there are planets 186 00:09:30,559 --> 00:09:33,160 Speaker 1: that are made out of rock and metals, which are 187 00:09:33,240 --> 00:09:35,480 Speaker 1: some of the densest things around, and the range of 188 00:09:35,520 --> 00:09:38,120 Speaker 1: densities tells us something about how the Solar System was 189 00:09:38,160 --> 00:09:41,160 Speaker 1: formed and what's under our feet and the incredible balance 190 00:09:41,480 --> 00:09:44,640 Speaker 1: between gravity and the other forces. Well, as usually, we 191 00:09:44,640 --> 00:09:46,720 Speaker 1: were wondering how many people have thought about the question, 192 00:09:46,920 --> 00:09:50,600 Speaker 1: which is then this planet, and so Daniel went out 193 00:09:50,600 --> 00:09:53,360 Speaker 1: there into the internet to find out. So thanks very 194 00:09:53,400 --> 00:09:56,080 Speaker 1: much to everyone who participates. If you've been listening to 195 00:09:56,080 --> 00:09:59,520 Speaker 1: the podcast and you would enjoy speculating about the next 196 00:09:59,520 --> 00:10:03,000 Speaker 1: topics for future episodes, please don't be shy. Right to 197 00:10:03,040 --> 00:10:05,960 Speaker 1: me two questions at Daniel and Jorge dot com and 198 00:10:06,000 --> 00:10:07,920 Speaker 1: we'll set you right up and think about it for 199 00:10:07,960 --> 00:10:11,560 Speaker 1: a second. Which do you think is the dancest planet? 200 00:10:12,280 --> 00:10:14,839 Speaker 1: Here's what people have to say. I think it would 201 00:10:14,880 --> 00:10:19,160 Speaker 1: either the Earth or Mars, but I'm pretty sure there's 202 00:10:19,200 --> 00:10:21,760 Speaker 1: more warts on Earthen on Mars. So just based on that, 203 00:10:21,800 --> 00:10:25,280 Speaker 1: I think Moss as the dancest planet in the Solar System. 204 00:10:25,480 --> 00:10:28,560 Speaker 1: I'm going to say, just to throw it out there, 205 00:10:30,000 --> 00:10:35,920 Speaker 1: the core of Jupiter or Mercury. Right now, I'm thinking 206 00:10:35,960 --> 00:10:43,120 Speaker 1: about all these crazy extra planets discovered recently but I 207 00:10:43,160 --> 00:10:48,800 Speaker 1: can already refer to our solar system, and from our 208 00:10:48,840 --> 00:10:55,600 Speaker 1: solar system the dancers planet it's art. Yes, it's Earth. 209 00:10:56,600 --> 00:10:58,480 Speaker 1: I'm going to go out on a limb and say 210 00:10:58,520 --> 00:11:02,480 Speaker 1: that the dancest planet in it is actually Jupiter, because 211 00:11:02,480 --> 00:11:04,719 Speaker 1: even though it is the most massive planet in our 212 00:11:04,720 --> 00:11:08,000 Speaker 1: solar system, I'm guessing that there's probably a part of 213 00:11:08,040 --> 00:11:11,040 Speaker 1: it that's super dense to keep it all together in 214 00:11:11,080 --> 00:11:15,320 Speaker 1: a solar system. Uh, I'm going to guess one of 215 00:11:15,400 --> 00:11:19,480 Speaker 1: the gas strands, the one with the most Let's go 216 00:11:19,559 --> 00:11:24,000 Speaker 1: with that, all right, some dance answers here. Not a 217 00:11:24,000 --> 00:11:26,560 Speaker 1: lot of love here, Yeah, a lot of variety in 218 00:11:26,600 --> 00:11:28,920 Speaker 1: the thinking and in the answers. I love it. I 219 00:11:29,000 --> 00:11:31,439 Speaker 1: like the people who argue that maybe we didn't specify 220 00:11:31,559 --> 00:11:35,480 Speaker 1: enough that we meant planet in our solar system, because like, 221 00:11:35,520 --> 00:11:37,320 Speaker 1: are we asking what's the dns is planet in the 222 00:11:37,440 --> 00:11:41,200 Speaker 1: universe or just in our little local neighborhood. Yeah, well, 223 00:11:41,240 --> 00:11:43,640 Speaker 1: the physicist and me wants to know what's the highest 224 00:11:43,760 --> 00:11:47,240 Speaker 1: density possible in a planet anywhere in the universe, and 225 00:11:47,280 --> 00:11:50,079 Speaker 1: also what is the most dense planet in our solar 226 00:11:50,080 --> 00:11:52,559 Speaker 1: syst I wanted real answers to all those questions. You're 227 00:11:52,640 --> 00:11:54,960 Speaker 1: dense with curiosity. But I guess maybe depends on what 228 00:11:55,000 --> 00:11:57,240 Speaker 1: you mean by a planet, Like what's the definition of 229 00:11:57,240 --> 00:11:59,840 Speaker 1: a planet? Like can a neutron star be a planet? 230 00:12:00,040 --> 00:12:01,880 Speaker 1: If you lived on the surface of a nutron star, 231 00:12:02,080 --> 00:12:04,920 Speaker 1: it would technically be your planet. I'm not sure. Maybe 232 00:12:04,920 --> 00:12:06,640 Speaker 1: it would be your star, you would be the planet. 233 00:12:06,720 --> 00:12:09,000 Speaker 1: But let's not get drawn into a forty minute rabbit 234 00:12:09,040 --> 00:12:12,000 Speaker 1: hole about the definition of a planet. That's a whole 235 00:12:12,200 --> 00:12:14,439 Speaker 1: briar patch. We don't want to get thrown into. Well, 236 00:12:14,480 --> 00:12:17,480 Speaker 1: what's the one sentence answer from a physicist, Well, the 237 00:12:17,520 --> 00:12:20,160 Speaker 1: official definition of a planet is a body that mostly 238 00:12:20,240 --> 00:12:23,280 Speaker 1: orbits the Sun and has cleared its own path in 239 00:12:23,320 --> 00:12:26,000 Speaker 1: the Solar system, a son, right, not just our son, 240 00:12:26,200 --> 00:12:29,199 Speaker 1: that's right, a son or maybe multiple suns, right, because 241 00:12:29,200 --> 00:12:32,720 Speaker 1: there are systems out there with binary stars at their hearts. Well, 242 00:12:32,760 --> 00:12:35,760 Speaker 1: we have how many plants in our Solar system? Eight planets? 243 00:12:35,840 --> 00:12:38,240 Speaker 1: We have officially eight planets in our Solar system and 244 00:12:38,320 --> 00:12:40,560 Speaker 1: a bunch of dwarf planets. Also, one of them is 245 00:12:40,559 --> 00:12:42,440 Speaker 1: the dances and I guess one of them is the 246 00:12:42,559 --> 00:12:46,199 Speaker 1: lightest planet. Or what's the opposite of DNS fluffy? Is 247 00:12:46,240 --> 00:12:48,720 Speaker 1: that the official physics word. I don't know what the 248 00:12:48,840 --> 00:12:52,320 Speaker 1: SI unit is for fluff, but it's the opposite of dance. 249 00:12:52,600 --> 00:12:55,960 Speaker 1: It's maybe measured in podcast episodes. It's measured in puns 250 00:12:56,000 --> 00:12:59,640 Speaker 1: per podcast episode or chuckles if we if we have 251 00:12:59,640 --> 00:13:03,240 Speaker 1: two many chuckles, it's not a very dense episode. All right, Well, 252 00:13:03,360 --> 00:13:05,920 Speaker 1: let's dig into this, Daniel, And let's maybe start with, 253 00:13:06,120 --> 00:13:08,480 Speaker 1: just like an average planet, what are planets made out of? 254 00:13:08,480 --> 00:13:11,120 Speaker 1: In our Solar System? So planets come in quite a 255 00:13:11,240 --> 00:13:15,000 Speaker 1: variety of stuff, right. The things that are planets are 256 00:13:15,040 --> 00:13:18,720 Speaker 1: made out of depend on where they were when the 257 00:13:18,760 --> 00:13:22,520 Speaker 1: planetary system was formed, because it all starts from one 258 00:13:22,559 --> 00:13:26,559 Speaker 1: big blob of ingredients. But the process of planetary formation 259 00:13:26,720 --> 00:13:30,080 Speaker 1: and stellar formation pulls different ingredients in different places. So 260 00:13:30,120 --> 00:13:33,040 Speaker 1: where you are in the Solar System as things are 261 00:13:33,120 --> 00:13:36,240 Speaker 1: forming determines what you sort of get made out of. 262 00:13:36,440 --> 00:13:39,120 Speaker 1: So it all comes down to understanding that process of 263 00:13:39,160 --> 00:13:41,360 Speaker 1: how you go from a huge cloud of gas and 264 00:13:41,440 --> 00:13:44,120 Speaker 1: dust and bits of rock left over from other Solar 265 00:13:44,120 --> 00:13:46,920 Speaker 1: systems that have now died and turned that into a 266 00:13:46,960 --> 00:13:49,600 Speaker 1: new Solar system. Right, and maybe just to take us back, 267 00:13:49,720 --> 00:13:51,920 Speaker 1: we start out in space, right, and there's usually a 268 00:13:51,960 --> 00:13:54,800 Speaker 1: huge cloud of stuff that came from the Big Bang 269 00:13:54,880 --> 00:13:57,720 Speaker 1: or maybe the remains of other suns that blew up 270 00:13:57,760 --> 00:14:00,960 Speaker 1: and slowly gravity brings all of that stuff together, which 271 00:14:00,960 --> 00:14:03,400 Speaker 1: is which is what forms the Sun and the planets. Right, 272 00:14:03,600 --> 00:14:06,520 Speaker 1: that's exactly right, And mostly it's hydrogen. You know, we've 273 00:14:06,600 --> 00:14:09,359 Speaker 1: been burning stuff in the hearts of stars for billions 274 00:14:09,400 --> 00:14:12,600 Speaker 1: of years, turning the hydrogen from the Big Bang into 275 00:14:12,679 --> 00:14:15,560 Speaker 1: helium and neon and carbon and iron and heavier stuff. 276 00:14:15,600 --> 00:14:18,240 Speaker 1: But we haven't made that much progress. The universe is 277 00:14:18,280 --> 00:14:22,560 Speaker 1: still like nineties something percent hydrogen. It's really just mostly 278 00:14:22,640 --> 00:14:25,960 Speaker 1: hydrogen deferst approximation. And so even though I'm not made 279 00:14:25,960 --> 00:14:28,680 Speaker 1: of hydrogen and you're not made of hydrogen, hygen is 280 00:14:28,760 --> 00:14:30,760 Speaker 1: the most common thing out there in the universe. So 281 00:14:30,760 --> 00:14:33,240 Speaker 1: if you're imagining this cloud that formed the Solar System, 282 00:14:33,320 --> 00:14:36,640 Speaker 1: it's mostly hydrogen with like a sprinkle of other stuff 283 00:14:36,680 --> 00:14:38,760 Speaker 1: like the iron and the magnesium. All that stuff is 284 00:14:38,800 --> 00:14:41,200 Speaker 1: like the spice on top of the meal. Right. Although 285 00:14:41,240 --> 00:14:43,760 Speaker 1: something interesting to think about is how much hydrogen we 286 00:14:43,840 --> 00:14:46,280 Speaker 1: actually are, right, I mean, we're mostly made out of water, 287 00:14:46,400 --> 00:14:50,160 Speaker 1: which is h two oh, right, and even our molecules 288 00:14:50,160 --> 00:14:53,800 Speaker 1: are you know, hydrocarbons are called hydrocarbon because they have hydrogen, 289 00:14:53,840 --> 00:14:55,840 Speaker 1: and yeah, that's true, and there's different ways of thinking 290 00:14:55,840 --> 00:14:59,680 Speaker 1: about it. Also hydrogen by number or hydrogen by mass, 291 00:15:00,200 --> 00:15:02,160 Speaker 1: because even if you have a lot of hydrogen, it's 292 00:15:02,200 --> 00:15:04,840 Speaker 1: not very heavy. And so the universe, for example, is 293 00:15:04,880 --> 00:15:09,520 Speaker 1: like hydrogen by number of molecules, but it's only seventies 294 00:15:09,520 --> 00:15:12,440 Speaker 1: something percent hydrogen by mass because the other stuff is 295 00:15:12,640 --> 00:15:15,280 Speaker 1: so much now or massive, even though there's less of it, 296 00:15:15,280 --> 00:15:17,240 Speaker 1: it counts for a bigger proportion of the mass of 297 00:15:17,240 --> 00:15:21,280 Speaker 1: the universe. So like in our bodies where maybe hydrogen 298 00:15:21,360 --> 00:15:23,760 Speaker 1: is the most popular atom, but maybe not the most 299 00:15:23,800 --> 00:15:26,240 Speaker 1: in terms of weight exactly, and so and if you 300 00:15:26,280 --> 00:15:28,640 Speaker 1: eat a lot of bread, then yeah, you're mostly carves. 301 00:15:30,160 --> 00:15:34,480 Speaker 1: And for example, the Sun today is like hydrogen, but 302 00:15:34,600 --> 00:15:36,960 Speaker 1: the Earth is much less. The Earth has a huge 303 00:15:36,960 --> 00:15:40,400 Speaker 1: fraction of oxygen and magnesium and iron, and so the 304 00:15:40,480 --> 00:15:43,400 Speaker 1: Earth and the Sun and Jupiter, they're not all like 305 00:15:43,680 --> 00:15:47,480 Speaker 1: representative samples of the stuff that started the Solar system. 306 00:15:47,480 --> 00:15:51,520 Speaker 1: It differentiated itself. It's separated. The process of that gravitational 307 00:15:51,640 --> 00:15:55,160 Speaker 1: collapse lead things to accumulate in different ways, which lead 308 00:15:55,200 --> 00:15:58,760 Speaker 1: to different sort of scoops. Of each material in different places, right, 309 00:15:58,760 --> 00:16:00,440 Speaker 1: Because you were saying it's sort of the pens and 310 00:16:00,480 --> 00:16:04,360 Speaker 1: where you are in the initial kind of cloud that 311 00:16:04,560 --> 00:16:08,000 Speaker 1: eventually became the Solar system, because I think what happened 312 00:16:08,080 --> 00:16:10,520 Speaker 1: was that most of the hydrogen that cloud kind of 313 00:16:10,680 --> 00:16:14,440 Speaker 1: rushed to the center, and that's where we're the Sun form, right, Yeah, exactly. 314 00:16:14,440 --> 00:16:16,960 Speaker 1: There's sort of three zones to think about. There's the center, 315 00:16:17,040 --> 00:16:19,840 Speaker 1: which forms the star, and you're right, that gathers most 316 00:16:19,880 --> 00:16:22,000 Speaker 1: of the gas, at least in the inner Solar system. 317 00:16:22,080 --> 00:16:24,680 Speaker 1: Then there's the inner part of it, which is you say, 318 00:16:24,760 --> 00:16:27,280 Speaker 1: doesn't have much gas for two reasons. One is that 319 00:16:27,360 --> 00:16:29,560 Speaker 1: the Sun steals a lot of it, and the other 320 00:16:30,000 --> 00:16:32,320 Speaker 1: is that the Sun blows away some of the gas. 321 00:16:32,640 --> 00:16:36,000 Speaker 1: Once the Sun gets going and starts emitting photons and 322 00:16:36,000 --> 00:16:38,760 Speaker 1: solar wind, it will strip the inner planets of any 323 00:16:38,800 --> 00:16:40,960 Speaker 1: gas they had. Remember that the Earth when it was 324 00:16:41,000 --> 00:16:45,240 Speaker 1: first formed, it had a primordial atmosphere of hydrogen and helium, 325 00:16:45,280 --> 00:16:47,720 Speaker 1: but most of that was lost because of the incredible 326 00:16:47,840 --> 00:16:50,840 Speaker 1: radiation from the Sun. So the inner planets don't really 327 00:16:50,920 --> 00:16:54,360 Speaker 1: keep much gas. That's why they're mostly rock. Their iron 328 00:16:54,400 --> 00:16:56,560 Speaker 1: and silica and that kind of stuff. Because the gas 329 00:16:56,560 --> 00:16:59,480 Speaker 1: either falls into the Sun or gets blown out into 330 00:16:59,480 --> 00:17:02,440 Speaker 1: the outer system by the radiation from the Sun. Right, 331 00:17:02,480 --> 00:17:04,800 Speaker 1: and I guess where did the rocks and the rocky 332 00:17:04,800 --> 00:17:08,479 Speaker 1: planets come from. They came from the hearts of other stars. Right. 333 00:17:08,560 --> 00:17:11,600 Speaker 1: Those rocks are made of heavier elements. And remember, astronomers 334 00:17:11,680 --> 00:17:15,000 Speaker 1: think of everything that's not hydrogen or helium as a metal. 335 00:17:15,119 --> 00:17:18,960 Speaker 1: And so these metals came from fusion inside the hearts 336 00:17:19,000 --> 00:17:22,520 Speaker 1: of other now dead stars. They started as hydrogen from 337 00:17:22,560 --> 00:17:24,840 Speaker 1: the Big Bang, or maybe a tiny little bit of helium. 338 00:17:24,880 --> 00:17:27,920 Speaker 1: They were fused into heavier stuff and lived for millions 339 00:17:28,000 --> 00:17:31,160 Speaker 1: or billions of years inside another star which then died. 340 00:17:31,240 --> 00:17:33,439 Speaker 1: And when it died, it blew out a lot of 341 00:17:33,440 --> 00:17:35,840 Speaker 1: that stuff out into the galaxy. And that's where these 342 00:17:35,920 --> 00:17:38,520 Speaker 1: raw materials come from. They float out there in these 343 00:17:38,560 --> 00:17:42,119 Speaker 1: big clouds until eventually they collapsed back again, triggered maybe 344 00:17:42,160 --> 00:17:44,800 Speaker 1: by a shock wave from a nearby supernova, or just 345 00:17:44,880 --> 00:17:48,520 Speaker 1: by a gravitational over density that gradually pulls this stuff 346 00:17:48,520 --> 00:17:51,520 Speaker 1: back together. Right, So initially we had this cloud of 347 00:17:51,600 --> 00:17:54,960 Speaker 1: hydrogen and some helium and a little bit, tiny little 348 00:17:54,960 --> 00:17:58,040 Speaker 1: bit of some rockies and metal and solid stuff. And 349 00:17:58,080 --> 00:18:01,160 Speaker 1: then I think what happened was that gas because it's lighter, 350 00:18:01,280 --> 00:18:03,840 Speaker 1: kind of rushed to the middle, right, leaving some of 351 00:18:03,880 --> 00:18:06,639 Speaker 1: the heavier stuff just around the Sun. That's where the 352 00:18:06,760 --> 00:18:09,560 Speaker 1: rocky planets came from. Yeah, So the processes, you have 353 00:18:09,680 --> 00:18:11,680 Speaker 1: the stars forming and at the same time you get 354 00:18:11,680 --> 00:18:15,160 Speaker 1: what's called a protoplanetary disk. At this disc of material, 355 00:18:15,160 --> 00:18:17,600 Speaker 1: it's sort of like the star has a ring system, right. 356 00:18:17,600 --> 00:18:20,080 Speaker 1: All the material which will eventually form the planets is 357 00:18:20,119 --> 00:18:22,880 Speaker 1: now flattened into a disc. Gravity is doing its job 358 00:18:22,960 --> 00:18:24,919 Speaker 1: of pulling it together, but it's hard to pull it 359 00:18:24,960 --> 00:18:27,439 Speaker 1: all into the Sun because if it's spinning around, it 360 00:18:27,480 --> 00:18:29,760 Speaker 1: has a lot of angular momentum, and so it sort 361 00:18:29,760 --> 00:18:33,040 Speaker 1: of stays in orbit rather than collapsing. So gravity collapses 362 00:18:33,080 --> 00:18:36,000 Speaker 1: it into that disc and places where you have enough 363 00:18:36,119 --> 00:18:38,800 Speaker 1: density where you have like heavy stuff like iron and 364 00:18:38,880 --> 00:18:41,840 Speaker 1: magnesium and rock that's able to compete with the gravity 365 00:18:42,080 --> 00:18:44,600 Speaker 1: of the Sun and pull some more stuff together. So 366 00:18:44,640 --> 00:18:46,440 Speaker 1: it's sort of like a race, you know, who can 367 00:18:46,440 --> 00:18:49,200 Speaker 1: get enough stuff to survive. If you don't pull enough 368 00:18:49,200 --> 00:18:51,560 Speaker 1: stuff in to get massive enough, then you just get 369 00:18:51,640 --> 00:18:54,440 Speaker 1: drawn into somebody else's gravity well. And so in our 370 00:18:54,440 --> 00:18:57,760 Speaker 1: solar system, we had a huge planet Jupiter start to form, 371 00:18:57,880 --> 00:19:00,879 Speaker 1: and it must have started from a gravitational density, and 372 00:19:00,880 --> 00:19:03,359 Speaker 1: then it got bigger and bigger and bigger, because the 373 00:19:03,400 --> 00:19:05,359 Speaker 1: more massive it is, the more gravity it has, the 374 00:19:05,359 --> 00:19:07,359 Speaker 1: more it pulls stuff in. And so each of the 375 00:19:07,400 --> 00:19:10,080 Speaker 1: planets sort of start from a spot in that protoplanetary 376 00:19:10,240 --> 00:19:12,560 Speaker 1: disk where you already had a little bit of extra 377 00:19:12,600 --> 00:19:15,440 Speaker 1: blob of stuff, and the mass of the planets tells 378 00:19:15,440 --> 00:19:18,399 Speaker 1: you something about the initial size of that over density. 379 00:19:18,440 --> 00:19:21,240 Speaker 1: The bigger it is, the faster it's able to gather mass, 380 00:19:21,280 --> 00:19:23,439 Speaker 1: and the bigger the planet ends up being kind of 381 00:19:23,440 --> 00:19:26,360 Speaker 1: like a maybe like a game of musical chairs, kind 382 00:19:26,359 --> 00:19:28,960 Speaker 1: of like everyone's trying to grab as much stuff as 383 00:19:29,000 --> 00:19:31,760 Speaker 1: possible before somebody else grabs it, right, yeah, sort of 384 00:19:31,800 --> 00:19:35,240 Speaker 1: like gravitational hungry hungry hippos, right, every just grabbing more 385 00:19:35,280 --> 00:19:37,240 Speaker 1: and more, and the bigger you are, the more hippos 386 00:19:37,240 --> 00:19:39,280 Speaker 1: you get, and the easier it is to grab stuff. 387 00:19:39,320 --> 00:19:41,000 Speaker 1: And in the inner Solar System you end up with 388 00:19:41,040 --> 00:19:44,520 Speaker 1: planets of rock and silica and iron because those are 389 00:19:44,520 --> 00:19:47,840 Speaker 1: the dense materials that can hold themselves together and resist 390 00:19:47,880 --> 00:19:50,040 Speaker 1: being pulled into the Sun. And then the gas of 391 00:19:50,080 --> 00:19:52,520 Speaker 1: course is blown out. Further out in the Solar System, 392 00:19:52,640 --> 00:19:55,960 Speaker 1: the Sun's radiation is weaker and the Sun's gravity is weaker, 393 00:19:56,119 --> 00:19:59,399 Speaker 1: and so gas giants can form. Jupiter and Saturn have 394 00:19:59,520 --> 00:20:03,320 Speaker 1: huge contributions from helium and from hydrogen because they were 395 00:20:03,320 --> 00:20:06,200 Speaker 1: far enough away from the Sun and grew fast enough 396 00:20:06,320 --> 00:20:08,480 Speaker 1: that they were able to compete with the Sun's gravity, 397 00:20:08,800 --> 00:20:11,399 Speaker 1: and their own gravity could protect their gas from the 398 00:20:11,440 --> 00:20:14,520 Speaker 1: Sun's radiation, which is also weaker that far out in 399 00:20:14,520 --> 00:20:17,200 Speaker 1: the Solar System. And while that's how we got the planets, 400 00:20:17,400 --> 00:20:20,000 Speaker 1: and some of them are denser than others, and some 401 00:20:20,119 --> 00:20:23,200 Speaker 1: of them is going to win the title of densest planet, 402 00:20:23,640 --> 00:20:25,040 Speaker 1: and I guess another one is going to win the 403 00:20:25,040 --> 00:20:27,840 Speaker 1: fluffiest planet, which is the one where I want to go. 404 00:20:28,000 --> 00:20:30,160 Speaker 1: And so let's get into those details. But first let's 405 00:20:30,160 --> 00:20:45,159 Speaker 1: take a quick break. All right, we're talking about the 406 00:20:45,280 --> 00:20:48,879 Speaker 1: densest planet in the Solar System. Daniel, where would you 407 00:20:48,880 --> 00:20:50,960 Speaker 1: put your money? I guess you know the end. Yes, 408 00:20:51,040 --> 00:20:53,640 Speaker 1: I know the answer, but I do like thinking about 409 00:20:53,680 --> 00:20:57,639 Speaker 1: it in terms of floating, like imagine some giant cosmic 410 00:20:57,720 --> 00:21:00,879 Speaker 1: tub of water on some you know, cosmic version of 411 00:21:00,920 --> 00:21:03,840 Speaker 1: the David Letterman Show and you're putting the planets in it, 412 00:21:04,119 --> 00:21:07,760 Speaker 1: Like will Saturn float? Or if you drop mercury into 413 00:21:07,840 --> 00:21:10,240 Speaker 1: a huge type of water, will it sink. That's just 414 00:21:10,280 --> 00:21:12,480 Speaker 1: sort of a fun experiment to do. Yeah, let's do it. 415 00:21:12,520 --> 00:21:14,719 Speaker 1: How much would it cost? I don't know. That's an 416 00:21:14,760 --> 00:21:19,040 Speaker 1: engineering problem. It's called David Letterman. He did pretty well 417 00:21:19,160 --> 00:21:21,720 Speaker 1: right with the show. He's sitting on some money. Yeah, 418 00:21:21,840 --> 00:21:23,880 Speaker 1: this would be like a great way out of retirement 419 00:21:23,920 --> 00:21:25,840 Speaker 1: for him. He's got some of that Netflix money now. 420 00:21:26,440 --> 00:21:29,000 Speaker 1: But it is an interesting question which is the densest planet? 421 00:21:29,040 --> 00:21:31,080 Speaker 1: And maybe you know, I feel like as we learn 422 00:21:31,119 --> 00:21:34,359 Speaker 1: about the planets, we learn about their size. Like you 423 00:21:34,400 --> 00:21:37,000 Speaker 1: sort of learned the Jupiter is the biggest one and 424 00:21:37,080 --> 00:21:39,880 Speaker 1: that Mercury is the smallest one, right, but you maybe 425 00:21:40,040 --> 00:21:42,040 Speaker 1: never think about the density of them. Yeah, we do 426 00:21:42,119 --> 00:21:44,400 Speaker 1: focus on the size because that's what we can see. 427 00:21:44,440 --> 00:21:47,080 Speaker 1: You look through your telescope, you can see Jupiter is big. 428 00:21:47,160 --> 00:21:49,760 Speaker 1: You can see Saturn is huge with these big rings. 429 00:21:49,920 --> 00:21:52,280 Speaker 1: So we know something about the size. And it's fun 430 00:21:52,280 --> 00:21:54,439 Speaker 1: to think about, right, It's fun to try to wrap 431 00:21:54,480 --> 00:21:58,000 Speaker 1: your mind around the incredible variety of sizes, right, Like 432 00:21:58,080 --> 00:22:01,040 Speaker 1: Jupiter is enormous, compared to the Earth. So it's really 433 00:22:01,040 --> 00:22:04,800 Speaker 1: fun to just like try to imagine filling Jupiter with 434 00:22:04,920 --> 00:22:07,320 Speaker 1: Earth's and then doing the same thing for the Sun, 435 00:22:07,400 --> 00:22:10,120 Speaker 1: like filling the Sun with jupiters, and imagining how many 436 00:22:10,200 --> 00:22:13,160 Speaker 1: Earths would fit inside the Sun, which is like a million. 437 00:22:13,359 --> 00:22:17,680 Speaker 1: And would Earth float in Jupiter if you like liquefied 438 00:22:17,760 --> 00:22:19,960 Speaker 1: Jupiter and put it in a tub, I don't know, 439 00:22:20,080 --> 00:22:22,639 Speaker 1: or if you like through Earth at Jupiter, would float? 440 00:22:23,720 --> 00:22:28,040 Speaker 1: Would float in Jupiter? Actually would not write. Earth is 441 00:22:28,119 --> 00:22:30,920 Speaker 1: much denser than Jupiter. It turns out, so Earth would 442 00:22:30,920 --> 00:22:34,159 Speaker 1: sink like a stone in the ocean of Jupiter. But 443 00:22:34,280 --> 00:22:37,760 Speaker 1: I guess how far right. Also, the definition of floating 444 00:22:37,920 --> 00:22:41,000 Speaker 1: kind of like, are we technically floating around the Sun? 445 00:22:41,240 --> 00:22:44,080 Speaker 1: I don't think there's any buoyancy, right, it's only gravity. 446 00:22:44,160 --> 00:22:45,960 Speaker 1: I think in order to be floating, you need to 447 00:22:46,000 --> 00:22:48,840 Speaker 1: have some sort of forces of buoyancy, you know, the displacement. 448 00:22:49,200 --> 00:22:51,320 Speaker 1: I don't think that's happening in our solar system. You 449 00:22:51,320 --> 00:22:54,040 Speaker 1: need the stuff from the thing that you're floating on 450 00:22:54,119 --> 00:22:56,640 Speaker 1: to be pushing you up, that's what you're saying, Yeah, exactly, 451 00:22:56,680 --> 00:22:58,880 Speaker 1: to be balancing gravity. Alright, Well, we're trying to get 452 00:22:58,880 --> 00:23:01,280 Speaker 1: to the answer of this question what is the densest planet. 453 00:23:01,280 --> 00:23:04,040 Speaker 1: And we've talked about how planets are FORGN because what 454 00:23:04,119 --> 00:23:05,960 Speaker 1: you're made out of sort of depends on where you 455 00:23:06,000 --> 00:23:09,880 Speaker 1: are in the Solar System when things started to form. Yeah, 456 00:23:09,880 --> 00:23:12,040 Speaker 1: and there's sort of four different categories of stuff that 457 00:23:12,080 --> 00:23:14,480 Speaker 1: planets can be made out of. There's like very heavy 458 00:23:14,480 --> 00:23:16,959 Speaker 1: metals like iron. You're gonna find that the inner planets 459 00:23:17,000 --> 00:23:18,919 Speaker 1: are mostly made out of stuff like that. And then 460 00:23:18,920 --> 00:23:21,200 Speaker 1: there's rock and that's also will be found mostly in 461 00:23:21,240 --> 00:23:23,720 Speaker 1: the inner planets. And then there's gas, which of course 462 00:23:23,760 --> 00:23:26,320 Speaker 1: the Sun and Jupiter and Saturn have huge servings of. 463 00:23:26,640 --> 00:23:28,720 Speaker 1: And then there's water. There is a lot of water 464 00:23:28,840 --> 00:23:31,439 Speaker 1: in the Solar System. And there's this very interesting point 465 00:23:31,680 --> 00:23:34,040 Speaker 1: where you're far enough away from the Sun. It's called 466 00:23:34,040 --> 00:23:37,280 Speaker 1: the frost line or the snow line, past which water 467 00:23:37,640 --> 00:23:41,680 Speaker 1: is ice instead of vapor, and beyond that line, water 468 00:23:41,840 --> 00:23:43,840 Speaker 1: is a solid. And so if you have a bunch 469 00:23:43,840 --> 00:23:47,119 Speaker 1: of water, it's frozen and it sort of contributes to 470 00:23:47,160 --> 00:23:50,040 Speaker 1: the mass the planet and it helps planets grow faster. 471 00:23:50,400 --> 00:23:53,400 Speaker 1: So planets like Urinous and Neptune, these are ice giants 472 00:23:53,400 --> 00:23:56,040 Speaker 1: because they have huge amounts of ice in them. Even 473 00:23:56,080 --> 00:23:59,320 Speaker 1: without accumulating a lot of hydrogen helium, they still were 474 00:23:59,320 --> 00:24:02,280 Speaker 1: able to grow really large. So the proportion of what 475 00:24:02,359 --> 00:24:04,680 Speaker 1: you get in the Solar System as you form really 476 00:24:04,680 --> 00:24:07,280 Speaker 1: does depend on where you are, right, although if you 477 00:24:07,280 --> 00:24:09,719 Speaker 1: put water out in space, even near Earth, it's going 478 00:24:09,760 --> 00:24:12,000 Speaker 1: to freeze to right, it's a really good question, and 479 00:24:12,000 --> 00:24:14,320 Speaker 1: it's sort of tricky. If it's close enough to the Sun, 480 00:24:14,800 --> 00:24:18,400 Speaker 1: then it will vaporize, right because it's very low pressure 481 00:24:18,440 --> 00:24:21,080 Speaker 1: out there in space, and the phase of a material 482 00:24:21,160 --> 00:24:24,600 Speaker 1: depends not just on the temperature but also on the pressure, 483 00:24:25,040 --> 00:24:28,160 Speaker 1: and so water will vaporize in space unless you're really 484 00:24:28,200 --> 00:24:30,240 Speaker 1: far out, so you mean like it's the really the 485 00:24:30,280 --> 00:24:33,320 Speaker 1: difference between vapor and solid like will jump straight from 486 00:24:33,600 --> 00:24:36,320 Speaker 1: a vapor to at some point if you put some 487 00:24:36,359 --> 00:24:39,160 Speaker 1: water out there, it will turn into an ice cube exactly, 488 00:24:39,200 --> 00:24:41,560 Speaker 1: Which is why I think if you go out into space, 489 00:24:41,920 --> 00:24:45,120 Speaker 1: parts of you will boil instantly right where boiling doesn't 490 00:24:45,160 --> 00:24:47,600 Speaker 1: mean you're getting really hot, It just means it's sublimating. 491 00:24:47,600 --> 00:24:50,200 Speaker 1: It's going directly to gas. And so you can boil 492 00:24:50,240 --> 00:24:52,680 Speaker 1: at a very low temperature if the pressure is very 493 00:24:52,800 --> 00:24:55,600 Speaker 1: very low, like you know, how if you're at high altitude, 494 00:24:55,640 --> 00:24:58,080 Speaker 1: you can boil your water at lower temperatures. It's like 495 00:24:58,280 --> 00:25:00,720 Speaker 1: harder to cook pasta at the top of Mount Everest 496 00:25:01,000 --> 00:25:04,240 Speaker 1: than it is in Death Valley because the water boils 497 00:25:04,280 --> 00:25:06,880 Speaker 1: at a lower temperature because of the lower pressure. Out 498 00:25:06,880 --> 00:25:09,879 Speaker 1: in deep space, water boils at very very low temperature, 499 00:25:10,080 --> 00:25:12,560 Speaker 1: and so it turns into vapor even if it's very cold. 500 00:25:12,640 --> 00:25:14,520 Speaker 1: So I think. So you were saying that the inner 501 00:25:14,520 --> 00:25:17,080 Speaker 1: planets are mostly met out of rocks because of where 502 00:25:17,119 --> 00:25:19,760 Speaker 1: they are, and the outer planets are mostly med at 503 00:25:19,760 --> 00:25:21,920 Speaker 1: a gas because of where they were. But that doesn't 504 00:25:21,960 --> 00:25:24,159 Speaker 1: mean that there aren't rocks and metals out there in 505 00:25:24,200 --> 00:25:26,760 Speaker 1: the outer Solar System. There still are, right, There's still 506 00:25:26,760 --> 00:25:29,440 Speaker 1: a lot of metal and earth, maybe the same amount 507 00:25:29,560 --> 00:25:31,719 Speaker 1: as there is in the inner Solar System. It's just 508 00:25:31,800 --> 00:25:34,280 Speaker 1: that the inner planets don't have gas because it was 509 00:25:34,320 --> 00:25:37,959 Speaker 1: all blown away, exactly. And there is definitely metal and 510 00:25:38,119 --> 00:25:40,639 Speaker 1: rock out there in the outer Solar System. You know, Pluto, 511 00:25:40,720 --> 00:25:43,320 Speaker 1: for example, is a lump of rock, and we suspect 512 00:25:43,600 --> 00:25:46,959 Speaker 1: that at the core of Jupiter and Saturn there is metal. 513 00:25:47,080 --> 00:25:50,080 Speaker 1: There is rock, absolutely, It's just that they also have 514 00:25:50,240 --> 00:25:53,600 Speaker 1: a lot of gas that accumulated all this hydrogen and 515 00:25:53,760 --> 00:25:56,760 Speaker 1: this helium as well, because right, because the Sun didn't 516 00:25:56,760 --> 00:26:00,199 Speaker 1: get to suck up that gas before Jupiter could take 517 00:26:00,240 --> 00:26:02,920 Speaker 1: it all bites for itself exactly. And Jupiter probably did 518 00:26:03,040 --> 00:26:06,360 Speaker 1: begin as it just metallic or rocky blob, and then 519 00:26:06,400 --> 00:26:08,480 Speaker 1: it gathered all that gas up with it. And the 520 00:26:08,520 --> 00:26:10,760 Speaker 1: same thing for the ice giants. They also definitely have 521 00:26:10,880 --> 00:26:13,239 Speaker 1: some rock and some metals inside of them. They just 522 00:26:13,359 --> 00:26:15,919 Speaker 1: also gathered a bunch of water as well. So that 523 00:26:15,960 --> 00:26:19,040 Speaker 1: helps you understand the mass the density is this combination 524 00:26:19,160 --> 00:26:22,919 Speaker 1: of size and mass, right, And so you might imagine 525 00:26:23,000 --> 00:26:24,840 Speaker 1: that the densest things would then be in the in 526 00:26:24,920 --> 00:26:27,680 Speaker 1: your Solar system, because that's like where you have almost 527 00:26:27,800 --> 00:26:31,400 Speaker 1: only the denser materials, right. But that's kind of interesting 528 00:26:31,400 --> 00:26:33,560 Speaker 1: to think about. Like if you took Jupiter and any 529 00:26:33,600 --> 00:26:35,639 Speaker 1: of those giant planets out there and you stripped them 530 00:26:35,640 --> 00:26:37,760 Speaker 1: a while their gas, or you've got rid of all 531 00:26:37,760 --> 00:26:39,920 Speaker 1: the gas in the Solar system, like all the planets 532 00:26:40,160 --> 00:26:42,320 Speaker 1: would maybe be kind of the same kind of right, 533 00:26:42,480 --> 00:26:45,359 Speaker 1: small dense rocky tiny balls. That's right. If you like 534 00:26:45,440 --> 00:26:48,760 Speaker 1: gas blasted Jupiter so you blew away all of its 535 00:26:48,760 --> 00:26:51,520 Speaker 1: helium and its hydrogen. Then you would be left with 536 00:26:51,520 --> 00:26:53,520 Speaker 1: the core, which we think we don't know. We're not 537 00:26:53,600 --> 00:26:55,920 Speaker 1: sure because of course we've never probed it the way 538 00:26:55,960 --> 00:26:58,440 Speaker 1: we probed the Earth. We think that probably there is 539 00:26:58,520 --> 00:27:01,160 Speaker 1: a rocky core there. Well, I read that Jupiter's core 540 00:27:01,240 --> 00:27:04,480 Speaker 1: is actually more fluffy, that it's not like a rocky core. 541 00:27:04,560 --> 00:27:07,800 Speaker 1: It's more like a kind of like a fuzzy rocky core. Yeah, well, 542 00:27:07,840 --> 00:27:10,720 Speaker 1: we're not exactly sure. There's definitely some rock and some ice. 543 00:27:10,840 --> 00:27:14,960 Speaker 1: It's also really interesting other chemical effects like surrounding the 544 00:27:15,080 --> 00:27:17,720 Speaker 1: rock on the ice. There is hydrogen, but it's not 545 00:27:17,840 --> 00:27:20,240 Speaker 1: hydrogen in the form that you're familiar with it. It's 546 00:27:20,240 --> 00:27:25,280 Speaker 1: called metallic hydrogen. Hydrogen that's under such intense pressure and 547 00:27:25,400 --> 00:27:29,119 Speaker 1: temperature that has formed this really strange phase. It's like 548 00:27:29,320 --> 00:27:31,520 Speaker 1: liquid hydrogen. But I think the point is that, you know, 549 00:27:31,680 --> 00:27:33,959 Speaker 1: if it wasn't for gas, the gas and that the 550 00:27:33,960 --> 00:27:36,920 Speaker 1: outer planets have and maybe some of the water, then 551 00:27:37,040 --> 00:27:38,880 Speaker 1: all the planets would be sort of the same, would 552 00:27:38,880 --> 00:27:41,200 Speaker 1: be small and rocky, and Peo wouldn't be talking about 553 00:27:41,520 --> 00:27:43,960 Speaker 1: the dens is one. But because those outer planets have 554 00:27:44,040 --> 00:27:46,520 Speaker 1: a lot of gas, then their density changes and there's 555 00:27:46,560 --> 00:27:49,600 Speaker 1: really interesting connection between the mass of a planet and 556 00:27:49,760 --> 00:27:52,240 Speaker 1: its density, because remember this more than just one thing 557 00:27:52,320 --> 00:27:54,800 Speaker 1: going on. It's not just like how much stuff do 558 00:27:54,840 --> 00:27:57,320 Speaker 1: you have and what element is it? Right, you might 559 00:27:57,359 --> 00:27:59,640 Speaker 1: think it's not just how much iron do you have 560 00:28:00,160 --> 00:28:02,280 Speaker 1: or versus how much gas do you have? But how 561 00:28:02,359 --> 00:28:05,399 Speaker 1: massive are you Because the larger the planet gets, the 562 00:28:05,440 --> 00:28:08,600 Speaker 1: stronger it's gravity and the stronger its ability to compress 563 00:28:08,720 --> 00:28:11,639 Speaker 1: itself to make it more dense. So it's not like 564 00:28:11,720 --> 00:28:13,680 Speaker 1: as you add mass to a planet, it just gets 565 00:28:13,720 --> 00:28:16,480 Speaker 1: bigger and stays the same density. As you add mass 566 00:28:16,520 --> 00:28:19,400 Speaker 1: to a planet actually also gets more dense, so its 567 00:28:19,400 --> 00:28:22,439 Speaker 1: size doesn't grow as quickly as its mass, right. But 568 00:28:22,480 --> 00:28:24,879 Speaker 1: it maybe it also depends on what you put into it, 569 00:28:24,920 --> 00:28:26,639 Speaker 1: what you're feeding it, right, Like if you're feeding it 570 00:28:26,680 --> 00:28:28,720 Speaker 1: a gas, then that's going to be maybe a little 571 00:28:28,800 --> 00:28:32,080 Speaker 1: harder to compress than the metal. Actually, the gas is 572 00:28:32,160 --> 00:28:35,040 Speaker 1: easier to compress the metal. Right. It has to do 573 00:28:35,080 --> 00:28:38,600 Speaker 1: with how compressible these materials are, and things like iron 574 00:28:38,680 --> 00:28:42,160 Speaker 1: and rock are harder to compress than things like hydrogen 575 00:28:42,440 --> 00:28:44,360 Speaker 1: and helium. And so if you look, for example, that 576 00:28:44,480 --> 00:28:48,000 Speaker 1: planets made out of ice or silicon or iron, then 577 00:28:48,040 --> 00:28:49,920 Speaker 1: there tends to be a bit more of a spread 578 00:28:50,200 --> 00:28:53,440 Speaker 1: between their mass and their density. It's not as closely connected. 579 00:28:53,800 --> 00:28:55,680 Speaker 1: But if you look at giant planets, and not just 580 00:28:55,720 --> 00:28:58,400 Speaker 1: in our Solar system, but in other solar systems, you 581 00:28:58,440 --> 00:29:01,120 Speaker 1: see a much tighter connection between the mass and the density. 582 00:29:01,480 --> 00:29:05,440 Speaker 1: As you add more mass, the density increases pretty quickly 583 00:29:05,480 --> 00:29:08,560 Speaker 1: for gas giants. It's not as tight relationship for the 584 00:29:08,600 --> 00:29:12,160 Speaker 1: lower mass planets made of metals and rocks. But in general, 585 00:29:12,280 --> 00:29:15,040 Speaker 1: the planets closer to the Sun are made mostly out 586 00:29:15,040 --> 00:29:18,120 Speaker 1: of rocky stuff. For example, let's talk about Mercury. Yeah, 587 00:29:18,200 --> 00:29:21,480 Speaker 1: so Mercury, you might imagine we should be the densest thing, right, 588 00:29:21,480 --> 00:29:24,320 Speaker 1: it's closest to the Sun. It's had all the low 589 00:29:24,440 --> 00:29:27,560 Speaker 1: density stuff blown off of it, and in fact it 590 00:29:27,640 --> 00:29:30,800 Speaker 1: is a really crazy planet. It's got like a metallic 591 00:29:30,880 --> 00:29:35,000 Speaker 1: core that's eighty five percent of its interior. So this 592 00:29:35,040 --> 00:29:38,360 Speaker 1: thing is mostly metal. It's really just like a huge 593 00:29:38,440 --> 00:29:43,080 Speaker 1: scoop of heavy metals surrounded by a thin layer of silica, 594 00:29:43,240 --> 00:29:46,160 Speaker 1: thin layer of rock. So to compare, Earth's core is 595 00:29:46,160 --> 00:29:50,440 Speaker 1: like of its interior is this metal, whereas Mercury it's 596 00:29:50,520 --> 00:29:54,040 Speaker 1: eighty five So Mercury is really a very dense blob 597 00:29:54,080 --> 00:29:56,320 Speaker 1: of stuff out there in the universe. Yeah, it's really 598 00:29:56,360 --> 00:29:58,360 Speaker 1: into heavy metal, but I think we hear you mean 599 00:29:58,400 --> 00:30:00,960 Speaker 1: actually actually like metal metal, right like. And for Earth 600 00:30:01,000 --> 00:30:04,520 Speaker 1: it's mostly iron, right like our course, mostly made out 601 00:30:04,560 --> 00:30:07,960 Speaker 1: of molten iron and as opposed to rock. Yeah, that's 602 00:30:07,960 --> 00:30:10,240 Speaker 1: exactly right. We're talking about iron, and there's also some 603 00:30:10,360 --> 00:30:12,000 Speaker 1: nickel in there. And you know, there's a lot of 604 00:30:12,080 --> 00:30:14,960 Speaker 1: uncertainty here. We know a lot about the Earth's core 605 00:30:15,280 --> 00:30:17,880 Speaker 1: because we can do things like study earthquakes, and as 606 00:30:17,920 --> 00:30:21,960 Speaker 1: those earthquakes reverberate around the surface, they bounce across those 607 00:30:22,080 --> 00:30:24,200 Speaker 1: layers in the Earth's core and they tell us something 608 00:30:24,240 --> 00:30:26,920 Speaker 1: about the density. It's like ringing the Earth like a 609 00:30:26,960 --> 00:30:30,040 Speaker 1: bell and studying those sound waves. We can't do that 610 00:30:30,080 --> 00:30:33,600 Speaker 1: as well on mercury because we don't have mercury quake sensors. 611 00:30:33,960 --> 00:30:36,040 Speaker 1: We do have those kind of sensors on Mars now 612 00:30:36,120 --> 00:30:38,400 Speaker 1: and on the Moon, so we can take direct measurements. 613 00:30:38,400 --> 00:30:40,200 Speaker 1: But the other ones were guessing a little bit more. 614 00:30:40,240 --> 00:30:43,360 Speaker 1: They come from planetary models and from our understanding of 615 00:30:43,400 --> 00:30:45,800 Speaker 1: the mass and the radius of these things. All right, 616 00:30:45,880 --> 00:30:51,040 Speaker 1: So mercury is basically like a solid ball of metal, right, 617 00:30:51,080 --> 00:30:53,560 Speaker 1: like a baby almost like a little ball of metal. 618 00:30:53,640 --> 00:30:56,360 Speaker 1: And so you would think maybe it's the densest planet 619 00:30:56,440 --> 00:30:58,360 Speaker 1: in the Solar System. You would think so, And it's 620 00:30:58,400 --> 00:31:01,680 Speaker 1: pretty dense. It comes out about five point for grams 621 00:31:01,720 --> 00:31:04,479 Speaker 1: per cubic centimeter, and so you know to orient yourself. 622 00:31:04,560 --> 00:31:08,240 Speaker 1: Water is one gram per cubic centimeter. So Mercury would 623 00:31:08,320 --> 00:31:12,160 Speaker 1: definitely not float. It's more than five times denser than water. 624 00:31:12,320 --> 00:31:15,440 Speaker 1: All right, So it's not Mercury the densest planet. I 625 00:31:15,440 --> 00:31:19,400 Speaker 1: guess maybe a question is what exactly makes something dense 626 00:31:19,520 --> 00:31:22,240 Speaker 1: or not? Well, density here is really connected to size. 627 00:31:22,640 --> 00:31:25,360 Speaker 1: As you add more stuff to the planet, it doesn't 628 00:31:25,440 --> 00:31:28,080 Speaker 1: just get bigger, right if you put a whole another 629 00:31:28,240 --> 00:31:32,120 Speaker 1: load of mass on Mercury, if you like, double Mercury's mass, 630 00:31:32,120 --> 00:31:35,080 Speaker 1: it wouldn't double its volume and then have the same 631 00:31:35,120 --> 00:31:38,960 Speaker 1: density because the gravity would get stronger, and so because 632 00:31:38,960 --> 00:31:42,320 Speaker 1: the gravity gets stronger, it would squeeze those atoms more tightly. 633 00:31:42,480 --> 00:31:45,080 Speaker 1: So the way to increase Mercury's density would be to 634 00:31:45,160 --> 00:31:48,880 Speaker 1: increase its mass. But Mercury is a pretty small planet. 635 00:31:49,160 --> 00:31:51,720 Speaker 1: It's not nearly the mass of the Earth or a 636 00:31:51,840 --> 00:31:54,120 Speaker 1: venus for example. Oh I see what you're saying, Like, 637 00:31:54,160 --> 00:31:57,600 Speaker 1: if maybe I added more stuff to mercury, even if 638 00:31:57,640 --> 00:32:00,000 Speaker 1: it was light stuff like gas, then it would increase 639 00:32:00,520 --> 00:32:03,760 Speaker 1: gravity and maybe squeeze that metal core even more and 640 00:32:03,800 --> 00:32:06,640 Speaker 1: make it more dense. Exactly, because the metal core of 641 00:32:06,720 --> 00:32:09,680 Speaker 1: mercury right now is denser than like if you just 642 00:32:09,720 --> 00:32:12,040 Speaker 1: took that metal and had it floating out into space, 643 00:32:12,160 --> 00:32:14,080 Speaker 1: if it was very cold and there was no pressure 644 00:32:14,120 --> 00:32:16,240 Speaker 1: on it, it would be much less dense. You take 645 00:32:16,320 --> 00:32:18,280 Speaker 1: that same amount of metal and you put it inside 646 00:32:18,320 --> 00:32:21,200 Speaker 1: mercury's core, it's gonna get squeezed down. It's gonna be 647 00:32:21,240 --> 00:32:23,600 Speaker 1: more dense than it otherwise would. So you add a 648 00:32:23,600 --> 00:32:26,720 Speaker 1: bunch more stuff to mercury, it's going to increase its density, 649 00:32:27,400 --> 00:32:29,480 Speaker 1: but maybe only up to a point, right Like this, 650 00:32:29,600 --> 00:32:32,080 Speaker 1: is there a maximum size for a rocky planet? Actually, 651 00:32:32,080 --> 00:32:35,480 Speaker 1: it's really interesting. We think that there's no maximum density 652 00:32:35,520 --> 00:32:38,320 Speaker 1: to a planet, but there is a maximum size to 653 00:32:38,400 --> 00:32:41,160 Speaker 1: a rocky planet. As a rocky planet gets larger and larger, 654 00:32:41,160 --> 00:32:43,880 Speaker 1: it also gets denser and denser because you're adding more 655 00:32:43,960 --> 00:32:47,200 Speaker 1: stuff and then increases the gravity and that makes it denser. 656 00:32:47,320 --> 00:32:50,160 Speaker 1: And this sort of this as emptotic size, you can't 657 00:32:50,200 --> 00:32:53,520 Speaker 1: really make a rocky planet bigger than about ten thousand 658 00:32:53,600 --> 00:32:57,640 Speaker 1: kilometers in radius. When you get to that radius, it's 659 00:32:57,720 --> 00:33:00,680 Speaker 1: so dense inside that if you add more stuff, it 660 00:33:00,720 --> 00:33:04,000 Speaker 1: doesn't actually increase the size at all. It just increases 661 00:33:04,040 --> 00:33:06,400 Speaker 1: the density. Like the gravity on that planet pulls that 662 00:33:06,480 --> 00:33:08,840 Speaker 1: new blob of stuff in and it just makes it 663 00:33:08,880 --> 00:33:12,760 Speaker 1: more dense. So for rocky planets, there's no maximum density 664 00:33:12,880 --> 00:33:15,760 Speaker 1: unless you think about black hole levels, but there is 665 00:33:15,800 --> 00:33:18,800 Speaker 1: probably a maximum size. Well, I think what you mean 666 00:33:18,920 --> 00:33:21,400 Speaker 1: is that when you're adding more rock to it, right, Like, 667 00:33:21,480 --> 00:33:23,640 Speaker 1: if you make a you have a rocky planet, then 668 00:33:23,680 --> 00:33:25,320 Speaker 1: you add more rocks to it, it's not going to 669 00:33:25,440 --> 00:33:27,800 Speaker 1: increase in size. It's just gonna get denser. But if 670 00:33:27,800 --> 00:33:29,800 Speaker 1: you add other kinds of stuff to it, it is 671 00:33:29,840 --> 00:33:32,040 Speaker 1: going to increase in size. Right, We're talking about rocky 672 00:33:32,080 --> 00:33:34,400 Speaker 1: planet is having a maximum size. So if you can 673 00:33:34,560 --> 00:33:36,360 Speaker 1: only make it out of rocks and metal, then there 674 00:33:36,520 --> 00:33:38,840 Speaker 1: is a maximum size. But you see sort of the 675 00:33:38,880 --> 00:33:42,040 Speaker 1: same kind of effect happening in our Solar System with 676 00:33:42,160 --> 00:33:45,720 Speaker 1: Jupiter and Saturn. For example, Jupiter is only a little 677 00:33:45,720 --> 00:33:48,640 Speaker 1: bit bigger than Saturn in terms of size, Like it's 678 00:33:48,720 --> 00:33:52,840 Speaker 1: radius is seventy thousand kilometers, whereas Saturn's is about sixty. 679 00:33:53,560 --> 00:33:57,600 Speaker 1: But Jupiter is more than three times more massive than Saturn, right, 680 00:33:57,640 --> 00:34:00,240 Speaker 1: And that's because as you add gas to sat Learned, 681 00:34:00,240 --> 00:34:02,360 Speaker 1: for example, to try to turn it into Jupiter, it 682 00:34:02,440 --> 00:34:05,640 Speaker 1: doesn't just grow in volume. That gas gets compressed and 683 00:34:05,720 --> 00:34:08,799 Speaker 1: gas is easier to compress than iron and metals. And 684 00:34:08,880 --> 00:34:11,440 Speaker 1: so that's why adding a lot more mass to Jupiter 685 00:34:11,560 --> 00:34:13,920 Speaker 1: also wouldn't make it much bigger. It would make it 686 00:34:14,000 --> 00:34:16,440 Speaker 1: denser faster than it would make it bigger. Right, But 687 00:34:16,480 --> 00:34:19,080 Speaker 1: it does get bigger though, right, It does get bigger. Absolutely, 688 00:34:19,120 --> 00:34:22,600 Speaker 1: So you can have really really huge gas planets. They 689 00:34:22,600 --> 00:34:25,799 Speaker 1: can get much bigger than rocky planets, absolutely, right. But 690 00:34:26,120 --> 00:34:28,719 Speaker 1: I guess so you're saying, like Jupiter is maybe like 691 00:34:28,880 --> 00:34:31,360 Speaker 1: maybe started off like a mercury, but then you added 692 00:34:31,400 --> 00:34:33,720 Speaker 1: a bunch of gas, and if you had added rocks, 693 00:34:34,040 --> 00:34:36,800 Speaker 1: it wouldn't have grown in size. But because you're adding gas, 694 00:34:37,040 --> 00:34:39,759 Speaker 1: it doesn't increase in size, although it also increases in 695 00:34:39,800 --> 00:34:43,240 Speaker 1: density because that gas gets compressed exactly, And there's also 696 00:34:43,280 --> 00:34:46,080 Speaker 1: a maximum size to a gas planet because if you 697 00:34:46,120 --> 00:34:49,160 Speaker 1: add enough gas to Jupiter, or what happens, it turns 698 00:34:49,200 --> 00:34:52,760 Speaker 1: into a star and the pressure in the interior ignites fusion, 699 00:34:53,040 --> 00:34:55,960 Speaker 1: and in fusion creates a lot of outwards pressure. So 700 00:34:56,000 --> 00:34:59,040 Speaker 1: then as you add more mass, the density goes down. 701 00:34:59,480 --> 00:35:03,200 Speaker 1: Like bigg your stars are less dense than smaller stars. 702 00:35:03,640 --> 00:35:07,280 Speaker 1: Once you cross that threshold from gas giant into star. 703 00:35:07,840 --> 00:35:10,680 Speaker 1: Then as you add mass, the density actually goes down 704 00:35:10,800 --> 00:35:15,200 Speaker 1: because the fusion increases and it fluffs up the star. Interesting, 705 00:35:15,400 --> 00:35:17,240 Speaker 1: and so I guess maybe in the case of Jupiter, 706 00:35:17,280 --> 00:35:19,120 Speaker 1: I would think that maybe that's a good candidate for 707 00:35:19,200 --> 00:35:22,359 Speaker 1: being the densest object. Then even though it's made out 708 00:35:22,400 --> 00:35:24,840 Speaker 1: of a lot of gas, there's a lot of gas 709 00:35:24,880 --> 00:35:27,239 Speaker 1: that's there and a lot of solid stuff in the middle. 710 00:35:27,320 --> 00:35:29,799 Speaker 1: Maybe it's compressing all that gas enough to make it 711 00:35:29,920 --> 00:35:31,799 Speaker 1: super dense. It's a good idea, And one of our 712 00:35:31,840 --> 00:35:34,160 Speaker 1: listeners might be right that the core of Jupiter is 713 00:35:34,200 --> 00:35:38,000 Speaker 1: probably very very dense, but Jupiter has so much hydrogen, 714 00:35:38,040 --> 00:35:40,840 Speaker 1: and hydrogen is just not very dense. That is actually 715 00:35:40,840 --> 00:35:43,440 Speaker 1: not very dense at all. Jupiter is like one point 716 00:35:43,520 --> 00:35:47,240 Speaker 1: three three grams per centimeter cute. Jupiter would not float, 717 00:35:47,400 --> 00:35:49,400 Speaker 1: but it almost would, right. I think That's what I 718 00:35:49,480 --> 00:35:51,640 Speaker 1: meant earlier, is that you know, gas is sort of 719 00:35:51,719 --> 00:35:55,560 Speaker 1: easy to compress, but ultimately is something like Jupiter. The 720 00:35:55,640 --> 00:35:59,320 Speaker 1: gas doesn't compress to something denser than rock. Yeah, exactly. 721 00:35:59,560 --> 00:36:01,520 Speaker 1: The gas is very low mass, right, and so it 722 00:36:01,560 --> 00:36:04,440 Speaker 1: doesn't contribute as much gravity as well. And Saturn is 723 00:36:04,520 --> 00:36:08,040 Speaker 1: even less dense than Jupiter. Saturn is actually points seven 724 00:36:08,160 --> 00:36:12,279 Speaker 1: grams per cubic meter, which means Saturn would float. If 725 00:36:12,360 --> 00:36:15,600 Speaker 1: Letterman could build a huge tupe of water, Saturn would 726 00:36:15,600 --> 00:36:17,920 Speaker 1: actually float in it. Well, I guess maybe a question 727 00:36:17,960 --> 00:36:21,160 Speaker 1: is why doesn't gas compressed as much as rocks? It 728 00:36:21,280 --> 00:36:23,799 Speaker 1: just doesn't have as much mass, right, It's not inherently 729 00:36:23,800 --> 00:36:26,439 Speaker 1: as dense. You don't have as many protons inside there, 730 00:36:26,560 --> 00:36:28,880 Speaker 1: So the compression is just due to gravity. Why can 731 00:36:28,960 --> 00:36:32,520 Speaker 1: I squeeze them closer together than I can with the metal? 732 00:36:32,800 --> 00:36:35,600 Speaker 1: It's not about squeezing the atoms closer together. It's about 733 00:36:35,600 --> 00:36:38,640 Speaker 1: the nucleus of the atom having more mass already, right, 734 00:36:38,640 --> 00:36:41,600 Speaker 1: There's all those extra protons in the nucleus of iron 735 00:36:42,040 --> 00:36:45,440 Speaker 1: and in silicon and in carbon and in oxygen that 736 00:36:45,520 --> 00:36:48,640 Speaker 1: makes it more massive and therefore having more gravity. But 737 00:36:48,680 --> 00:36:51,759 Speaker 1: couldn't I then squeeze the hydrogen atoms closer together? The 738 00:36:51,800 --> 00:36:54,680 Speaker 1: reason it's hard to compress hydrogen, of course, is because 739 00:36:54,719 --> 00:36:57,439 Speaker 1: the electrons repel each other, and if you squeeze even 740 00:36:57,480 --> 00:37:00,480 Speaker 1: further than the protons in the nuclei will reject each 741 00:37:00,520 --> 00:37:02,760 Speaker 1: other as well will repel each other. So the atoms 742 00:37:02,800 --> 00:37:04,960 Speaker 1: don't like to be compressed beyond a certain point. But 743 00:37:05,040 --> 00:37:07,040 Speaker 1: if you have the same sort of number density of 744 00:37:07,120 --> 00:37:10,440 Speaker 1: hydrogen and number density of iron, like you have a 745 00:37:10,520 --> 00:37:13,720 Speaker 1: million iron atoms in a cubic meter versus a million 746 00:37:13,800 --> 00:37:16,680 Speaker 1: hydrogen atoms, you're gonna get a lot more gravity from 747 00:37:16,719 --> 00:37:19,239 Speaker 1: the iron atoms. You're gonna get a lot more density. 748 00:37:19,280 --> 00:37:22,480 Speaker 1: All right, Well, Mercury, apparently it's not the densest planet, 749 00:37:22,560 --> 00:37:25,800 Speaker 1: even though it's the smallest and the rockiest, and Jupiter 750 00:37:26,400 --> 00:37:28,920 Speaker 1: is the largest planet. But it's also not the dances 751 00:37:29,120 --> 00:37:31,799 Speaker 1: and so let's get into which planet is the dance 752 00:37:31,960 --> 00:37:35,399 Speaker 1: is planet in our Solar system. But first let's take 753 00:37:35,440 --> 00:37:50,279 Speaker 1: another quick break. Al Right, we are giving out an 754 00:37:50,320 --> 00:37:53,480 Speaker 1: award for the dances planet in the Solar system, Daniel, 755 00:37:53,600 --> 00:37:56,200 Speaker 1: what is our planet gonna win for being the dances planet. 756 00:37:56,239 --> 00:37:58,319 Speaker 1: It's gonna win a huge blue ribbon and we're gonna 757 00:37:58,320 --> 00:38:00,800 Speaker 1: give it a nice pat of butter after we toasted 758 00:38:00,840 --> 00:38:03,239 Speaker 1: for lunch. I thought you were going to get a 759 00:38:03,280 --> 00:38:06,439 Speaker 1: bouquet of bread or a nice day at the spot 760 00:38:06,480 --> 00:38:08,960 Speaker 1: where they can float in a tub all day or 761 00:38:09,000 --> 00:38:10,840 Speaker 1: not float, I guess, or sink into a tub and 762 00:38:10,880 --> 00:38:12,560 Speaker 1: they're gonna have to float in like a tub of 763 00:38:12,600 --> 00:38:15,920 Speaker 1: molten lead or something like that. Well, yeah, I mean 764 00:38:16,000 --> 00:38:20,040 Speaker 1: that could be relaxing, I guess, if not totally poisonous. Yeah, 765 00:38:20,080 --> 00:38:22,440 Speaker 1: you do, you man, treat yourself all right. Well, the 766 00:38:22,480 --> 00:38:25,560 Speaker 1: densist planet, apparently is not Mercury, which is the smallest 767 00:38:25,640 --> 00:38:28,560 Speaker 1: and rockiest one that is mostly made out of metal. 768 00:38:28,600 --> 00:38:31,440 Speaker 1: And it's not Jupiter, which is the biggest planet and 769 00:38:31,560 --> 00:38:34,839 Speaker 1: most massive planet in our solar system, Daniel, which one 770 00:38:34,920 --> 00:38:36,960 Speaker 1: is the densest planet. It's not Pluto, is it. It's 771 00:38:37,000 --> 00:38:40,600 Speaker 1: not Pluto. No, it's actually the Earth. Earth is the 772 00:38:40,680 --> 00:38:43,839 Speaker 1: densest planet in the Solar system. We win this one, 773 00:38:44,239 --> 00:38:48,120 Speaker 1: What surprise plot twist? It was us all along, It 774 00:38:48,280 --> 00:38:51,560 Speaker 1: was all along. The answer was the planet we loved 775 00:38:51,719 --> 00:38:53,880 Speaker 1: along the way, but not by much, right, Like, the 776 00:38:53,960 --> 00:38:56,759 Speaker 1: Earth is like five and a half grass per cubic 777 00:38:56,840 --> 00:38:59,759 Speaker 1: centimeter and Mercury is like five point four three, which 778 00:38:59,760 --> 00:39:02,480 Speaker 1: is pretty close. Yeah, And the reason the Earth winds 779 00:39:02,680 --> 00:39:05,640 Speaker 1: is just because it's more massive, like whatever happened in 780 00:39:05,680 --> 00:39:09,760 Speaker 1: the very early Solar system. Earth started forming before Mercury, 781 00:39:09,880 --> 00:39:12,680 Speaker 1: or it formed from a larger initial blob, either one, 782 00:39:12,760 --> 00:39:15,200 Speaker 1: and so he was able to like hungry, hungry hippo 783 00:39:15,239 --> 00:39:17,600 Speaker 1: its way to just more stuff. And so because we 784 00:39:17,680 --> 00:39:20,239 Speaker 1: have more stuff, we don't just get bigger again, we 785 00:39:20,239 --> 00:39:23,719 Speaker 1: get more compressed. Right, more stuff means more gravity, which 786 00:39:23,719 --> 00:39:27,160 Speaker 1: means more gravitational pressure, which means that the stuff we're 787 00:39:27,200 --> 00:39:30,240 Speaker 1: made out of is squeezed more than the stuff mercury 788 00:39:30,280 --> 00:39:32,480 Speaker 1: is made out of, just because there's more of it. 789 00:39:32,960 --> 00:39:35,279 Speaker 1: And so that's why Earth is able to eke out 790 00:39:35,360 --> 00:39:38,279 Speaker 1: above Mercury like you would naively expect. And if all 791 00:39:38,320 --> 00:39:40,840 Speaker 1: the planets had the same mass, you would expect that 792 00:39:40,880 --> 00:39:43,080 Speaker 1: the ones closer to the Sun would be denser for 793 00:39:43,080 --> 00:39:45,560 Speaker 1: the reasons we've discussed several times as you went out, 794 00:39:45,600 --> 00:39:48,440 Speaker 1: that would be less and less dense. But there's another 795 00:39:48,480 --> 00:39:51,400 Speaker 1: factor there, which is a total mass. More mass means 796 00:39:51,520 --> 00:39:55,839 Speaker 1: more density for these planets. But we're also bigger than mercury, right, Like, 797 00:39:56,160 --> 00:40:00,359 Speaker 1: we're both larger in size and also denser. Exactly, we're 798 00:40:00,440 --> 00:40:03,200 Speaker 1: larger we're more massive, and we're only a little bit 799 00:40:03,280 --> 00:40:06,279 Speaker 1: denser than mercury. Were like just barely eat out. It's 800 00:40:06,280 --> 00:40:09,440 Speaker 1: like five point five one versus five point four three 801 00:40:09,640 --> 00:40:13,200 Speaker 1: grams per cubic centimeters, so neither of us would float 802 00:40:13,200 --> 00:40:15,880 Speaker 1: in water. Right, But it's again it's not just because 803 00:40:15,920 --> 00:40:18,480 Speaker 1: we have more mass, because Jupiter definitely has thousands of 804 00:40:18,520 --> 00:40:20,759 Speaker 1: times more mass than Earth, but it's not as dense 805 00:40:20,800 --> 00:40:24,719 Speaker 1: as Earth because gas doesn't get compressed as much. Yea 806 00:40:24,840 --> 00:40:27,200 Speaker 1: jupiters around three hundred times in the mass of the Earth, 807 00:40:27,200 --> 00:40:29,760 Speaker 1: but you're right, it's much less dense. So the reason 808 00:40:29,800 --> 00:40:31,960 Speaker 1: that we're denser is because we are made out of 809 00:40:32,040 --> 00:40:34,799 Speaker 1: rocks and metals instead of gas, and we'll also have 810 00:40:34,840 --> 00:40:38,160 Speaker 1: a bigger scuba stuff than mercury. So we're denser than 811 00:40:38,239 --> 00:40:40,720 Speaker 1: Jupiter because we're made of denser stuff, and we're denser 812 00:40:40,760 --> 00:40:43,839 Speaker 1: than mercury because we're made of more dense stuff. All right, 813 00:40:43,880 --> 00:40:46,279 Speaker 1: So the Earth is about five point five grams per 814 00:40:46,320 --> 00:40:51,640 Speaker 1: cubic centimeters and mercury is five point four grasper cubic centimeters. 815 00:40:51,680 --> 00:40:54,280 Speaker 1: What were some of the other close runner ups. Venus, 816 00:40:54,320 --> 00:40:57,160 Speaker 1: which is right between us, is five point two grams 817 00:40:57,320 --> 00:41:00,440 Speaker 1: per cubic centimeters, So it's like right around there. You know, 818 00:41:00,480 --> 00:41:03,640 Speaker 1: these three inner planets are all very similar in mass, 819 00:41:03,640 --> 00:41:05,640 Speaker 1: super closed, right, like if you were to round to 820 00:41:05,800 --> 00:41:09,799 Speaker 1: the you know, nearest single digit. Uh, they're about the same. Yeah, 821 00:41:09,880 --> 00:41:12,120 Speaker 1: And except for the Earth, it sort of follows the 822 00:41:12,120 --> 00:41:14,680 Speaker 1: trend you expect. You know, Earth is the most massive, 823 00:41:14,719 --> 00:41:17,640 Speaker 1: but then it's mercury than Venus than Mars, which is 824 00:41:17,680 --> 00:41:20,960 Speaker 1: almost four grams per cubic centimeter, So the Earth is 825 00:41:21,000 --> 00:41:22,759 Speaker 1: sort of an outlier there, right, it's sort of like 826 00:41:23,040 --> 00:41:25,319 Speaker 1: the weird one. Other than that, it follows the rule 827 00:41:25,680 --> 00:41:27,680 Speaker 1: of the inner planets being the densest and then it 828 00:41:27,840 --> 00:41:30,520 Speaker 1: falling as you get further from the Sun. So the 829 00:41:30,560 --> 00:41:32,399 Speaker 1: Earth just sort of like happened to be a big 830 00:41:32,440 --> 00:41:34,880 Speaker 1: boy or big girl or a big thing. It's just 831 00:41:34,880 --> 00:41:37,480 Speaker 1: having to get more stuff, right, because Mars is further out, 832 00:41:37,520 --> 00:41:40,000 Speaker 1: but it's smaller. Yeah, Mars is further out and it's 833 00:41:40,040 --> 00:41:42,960 Speaker 1: also smaller, and so it can't really compete, right. And 834 00:41:42,960 --> 00:41:45,520 Speaker 1: then at some point in the Solar System, the planets 835 00:41:45,560 --> 00:41:48,600 Speaker 1: become gas planets, right, which is where Jupiter and Saturn 836 00:41:48,680 --> 00:41:51,480 Speaker 1: commit and those guys are about roughly the density of 837 00:41:51,480 --> 00:41:53,439 Speaker 1: water you know, Jupiter is just a little bit more 838 00:41:53,480 --> 00:41:56,640 Speaker 1: dense than water at one point three grams per centimeter cube, 839 00:41:56,680 --> 00:41:58,880 Speaker 1: and Saturn is a little bit less dense than water 840 00:41:59,280 --> 00:42:02,719 Speaker 1: at points set than Graham's per centimeters cubed. So it's 841 00:42:02,719 --> 00:42:04,600 Speaker 1: interesting because then if you had a cup of water, 842 00:42:05,000 --> 00:42:08,600 Speaker 1: it would sink in Jupiter technically, but it would float. 843 00:42:09,000 --> 00:42:11,120 Speaker 1: Now it would sink in Saturn, but it would float 844 00:42:11,280 --> 00:42:15,320 Speaker 1: in Jupiter. Yeah, exactly. If you spill your beverage and Jupiter, 845 00:42:15,400 --> 00:42:17,400 Speaker 1: don't worry. You can just you know, bend down with 846 00:42:17,400 --> 00:42:19,360 Speaker 1: your straw and surp it up. It's gonna be floating 847 00:42:19,400 --> 00:42:22,439 Speaker 1: over the surface of Jupiter, right well, technically also maybe 848 00:42:22,440 --> 00:42:25,720 Speaker 1: in Saturn, right because we're talking about average densities. Yeah, exactly. 849 00:42:25,760 --> 00:42:28,000 Speaker 1: And it's a little bit fuzzy there, right, Like, because 850 00:42:28,040 --> 00:42:30,719 Speaker 1: the edge of Jupiter is fuzzy. It's easy to say 851 00:42:30,760 --> 00:42:33,719 Speaker 1: where we think the Earth ends right at the surface, 852 00:42:33,880 --> 00:42:35,719 Speaker 1: but it's harder to say, like where to draw the 853 00:42:35,760 --> 00:42:38,120 Speaker 1: line for Jupiter because it doesn't have a hard surface 854 00:42:38,200 --> 00:42:41,160 Speaker 1: the way Earth does. So they sort of arbitrarily defined 855 00:42:41,440 --> 00:42:43,920 Speaker 1: some drop off in the density as the edge of Jupiter. 856 00:42:44,080 --> 00:42:45,960 Speaker 1: But that changes the number. You know, if you push 857 00:42:46,000 --> 00:42:49,359 Speaker 1: further out to include Jupiter's full atmosphere and exosphere, then 858 00:42:49,400 --> 00:42:51,840 Speaker 1: the density would drop even further. The density at the 859 00:42:51,880 --> 00:42:54,640 Speaker 1: core of these planets is much higher than the density 860 00:42:54,880 --> 00:42:57,760 Speaker 1: near the edges. Right, Like you said, Jupiter has metallic 861 00:42:57,880 --> 00:43:00,880 Speaker 1: hydrogen at its core, and Saturn I think it rains 862 00:43:00,920 --> 00:43:04,440 Speaker 1: diamonds too, right, Like, things are pretty intense inside of 863 00:43:04,440 --> 00:43:07,359 Speaker 1: these fluffy planets. Yeah, and that's one reason that it's 864 00:43:07,400 --> 00:43:09,719 Speaker 1: hard to study. We have dropped probes into some of 865 00:43:09,719 --> 00:43:11,640 Speaker 1: these things, but they don't last very long because the 866 00:43:11,680 --> 00:43:15,480 Speaker 1: pressure gets very intense pretty quickly. Right. So then after 867 00:43:15,520 --> 00:43:19,839 Speaker 1: these gassy, gassy planets, then you have the icy planets, right, 868 00:43:19,960 --> 00:43:22,600 Speaker 1: Urinus and Neptune, and those are actually denser than the 869 00:43:22,640 --> 00:43:25,600 Speaker 1: gassy planets. Yeah, Urinus is about the same as Jupiter, 870 00:43:25,640 --> 00:43:28,800 Speaker 1: but Neptune is even denser. It's one point six grams 871 00:43:28,840 --> 00:43:31,560 Speaker 1: per centimeter cubed. And that's just because it has more water, 872 00:43:31,719 --> 00:43:34,920 Speaker 1: more ice. It's out past the frost line, and so 873 00:43:35,000 --> 00:43:36,880 Speaker 1: it can get a little bit more solid. It's a 874 00:43:36,880 --> 00:43:39,640 Speaker 1: little bit more like the rocky planets than like the 875 00:43:39,680 --> 00:43:42,320 Speaker 1: gas planets. I mean, it's still more like a gas planet, 876 00:43:42,320 --> 00:43:44,520 Speaker 1: but sort of in the rocky direction because it has 877 00:43:44,760 --> 00:43:46,840 Speaker 1: more ice in it. Right. It kind of seems to 878 00:43:46,920 --> 00:43:50,160 Speaker 1: depend on what you're most of your mass comes from, right, Like, 879 00:43:50,200 --> 00:43:51,960 Speaker 1: if your most of your mass comes from rocks, then 880 00:43:51,960 --> 00:43:54,680 Speaker 1: you're going to be more dense. If it most mostly 881 00:43:54,680 --> 00:43:56,719 Speaker 1: comes from gas, you're gonna be the least dense. And 882 00:43:56,719 --> 00:43:59,640 Speaker 1: if it mostly comes from water, then you're sort of 883 00:43:59,680 --> 00:44:01,480 Speaker 1: in the mid Yeah, And it's a really cool way 884 00:44:01,520 --> 00:44:03,680 Speaker 1: to sort of indicate what you're made out of, which 885 00:44:03,719 --> 00:44:06,200 Speaker 1: tells you where you were formed in the Solar System 886 00:44:06,239 --> 00:44:09,280 Speaker 1: and something about the whole history of the Solar System's formation. 887 00:44:09,480 --> 00:44:12,000 Speaker 1: There's so much wrapped information wrapped up in these few numbers, 888 00:44:12,000 --> 00:44:14,640 Speaker 1: you know, the mass, the radius, the density. That tells 889 00:44:14,680 --> 00:44:16,760 Speaker 1: you a lot about the history of each planet. Alright, 890 00:44:16,800 --> 00:44:20,320 Speaker 1: So eartha, we are the densest planet in our Solar system. 891 00:44:20,440 --> 00:44:24,200 Speaker 1: That's um. I guess that's a good distinction, right Like 892 00:44:24,280 --> 00:44:27,600 Speaker 1: dense is good. It means more more is happening. We're 893 00:44:27,640 --> 00:44:30,840 Speaker 1: not to be taken lightly, that's for sure. It's a 894 00:44:30,880 --> 00:44:33,960 Speaker 1: pretty heavy topic, but you know, on cosmic scales, these 895 00:44:33,960 --> 00:44:36,839 Speaker 1: are not very impressive densities. You were talking earlier about 896 00:44:36,840 --> 00:44:40,480 Speaker 1: neutron stars. Remember that if water is one gram per 897 00:44:40,520 --> 00:44:44,720 Speaker 1: cubic centimeter. A neutron star is tend to the eleven 898 00:44:45,040 --> 00:44:49,400 Speaker 1: kilograms per cubic centimeter. Right, it's just like way off 899 00:44:49,400 --> 00:44:52,920 Speaker 1: the scale, you know, orders and orders of aptitude. Remember 900 00:44:52,920 --> 00:44:56,240 Speaker 1: that a teaspoon of neutron star material is like seven 901 00:44:56,320 --> 00:45:00,520 Speaker 1: hundred thousand Eiffel towers all squeezed into a tie any spot. 902 00:45:00,680 --> 00:45:03,959 Speaker 1: So the universe is capable of creating stuff at much 903 00:45:04,040 --> 00:45:07,439 Speaker 1: much higher densities than we see in our solar system. Right. 904 00:45:07,560 --> 00:45:09,879 Speaker 1: I guess it depends on how much mass you get 905 00:45:09,920 --> 00:45:13,000 Speaker 1: to accumulate into a small spot. So basically anything would 906 00:45:13,040 --> 00:45:16,560 Speaker 1: float in a neutron star, even six stunded thousand Eiffel towers. 907 00:45:16,640 --> 00:45:18,720 Speaker 1: I don't know if you'd call it floating. Neutron stars 908 00:45:18,760 --> 00:45:21,240 Speaker 1: actually have a crust, right, So you could build Eiffel 909 00:45:21,280 --> 00:45:23,480 Speaker 1: towers on the surface of a nutron star if you 910 00:45:23,520 --> 00:45:26,000 Speaker 1: made them strong enough, because nothing can be higher than 911 00:45:26,040 --> 00:45:28,879 Speaker 1: about a millimeter above the surface of a neutron star 912 00:45:28,920 --> 00:45:32,000 Speaker 1: because the gravity is so intense that it just gets flattened. 913 00:45:32,080 --> 00:45:33,919 Speaker 1: So yeah, if you spill your drink on a neutron star, 914 00:45:33,960 --> 00:45:37,640 Speaker 1: it's going to be a very thin puddle on the surface, right, Yeah, well, well, 915 00:45:37,680 --> 00:45:41,000 Speaker 1: well it would be a potal but you'd still be floating. Well, 916 00:45:41,000 --> 00:45:43,280 Speaker 1: those are the planets in our Solar system. What about 917 00:45:43,400 --> 00:45:46,719 Speaker 1: out there into the cosmos um One of our listeners 918 00:45:46,719 --> 00:45:49,240 Speaker 1: here I was asking whether we meant the Solar System 919 00:45:49,560 --> 00:45:52,560 Speaker 1: or the exoplanets out there in other parts of the 920 00:45:52,600 --> 00:45:55,680 Speaker 1: galaxy and other galaxies. Yeah. One of the really fun 921 00:45:55,760 --> 00:45:58,439 Speaker 1: things about modern astronomy is that we are now able 922 00:45:58,480 --> 00:46:01,920 Speaker 1: to use our telescopes to study planets around other stars, 923 00:46:02,000 --> 00:46:04,680 Speaker 1: which gives us this amazing window into the question of 924 00:46:04,719 --> 00:46:07,680 Speaker 1: whether our Solar system is weird or typical. You know, 925 00:46:07,680 --> 00:46:09,719 Speaker 1: in the end, it's sort of a statistics question. We're 926 00:46:09,719 --> 00:46:12,480 Speaker 1: like one example out of many, many stars, and we 927 00:46:12,520 --> 00:46:15,799 Speaker 1: want to know are we usual? Are we weird? You know? 928 00:46:15,840 --> 00:46:18,080 Speaker 1: How could we be different? Is the fact that there's 929 00:46:18,160 --> 00:46:20,840 Speaker 1: life on this Solar system mean that our Solar system 930 00:46:20,920 --> 00:46:23,279 Speaker 1: has to be different? Or if our Solar system is 931 00:46:23,320 --> 00:46:26,000 Speaker 1: normal and usual, does that mean there's life everywhere in 932 00:46:26,040 --> 00:46:29,120 Speaker 1: the Solar System. It's really big and fun question, and 933 00:46:29,160 --> 00:46:32,399 Speaker 1: it's actually not that hard to think about the densities 934 00:46:32,560 --> 00:46:35,600 Speaker 1: of these planets, because to measure the density you only 935 00:46:35,640 --> 00:46:38,560 Speaker 1: need to know their mass. And their size, right, Because 936 00:46:38,680 --> 00:46:41,000 Speaker 1: it's an interesting question because it could be then maybe 937 00:46:41,120 --> 00:46:44,000 Speaker 1: other solar systems out there in the universe are totally 938 00:46:44,040 --> 00:46:46,799 Speaker 1: different than ours. Right, it could be that ours is like, 939 00:46:47,320 --> 00:46:49,759 Speaker 1: you know, a weird one where we form planets. But 940 00:46:49,800 --> 00:46:51,800 Speaker 1: it could be that maybe that in other solar systems, 941 00:46:52,000 --> 00:46:54,480 Speaker 1: maybe you don't even form planets, or you form like 942 00:46:54,520 --> 00:46:57,239 Speaker 1: one giant planet, or you only form two planets or 943 00:46:57,280 --> 00:46:59,880 Speaker 1: something like that, right, yeah, Or they're all gas giants. 944 00:47:00,080 --> 00:47:02,839 Speaker 1: Maybe rocky planets are super rare in the universe, or 945 00:47:02,920 --> 00:47:06,200 Speaker 1: maybe they're all rocky planets. Right until we started looking 946 00:47:06,239 --> 00:47:08,400 Speaker 1: at other solar systems and we didn't know the answer 947 00:47:08,440 --> 00:47:10,480 Speaker 1: to this. Now we actually know that there are a 948 00:47:10,520 --> 00:47:13,200 Speaker 1: lot of gas giants out there. We call them hot jupiters. 949 00:47:13,440 --> 00:47:15,760 Speaker 1: A lot of them are really big gas giants close 950 00:47:15,840 --> 00:47:18,719 Speaker 1: to their sun. We also have identified a lot of 951 00:47:18,840 --> 00:47:22,040 Speaker 1: rocky planets, so we know that there's rocky planets out there, 952 00:47:22,040 --> 00:47:24,600 Speaker 1: and there are gassy planets out there, and there's a 953 00:47:24,719 --> 00:47:28,160 Speaker 1: huge variety also in the density of these planets. Right. 954 00:47:28,200 --> 00:47:30,560 Speaker 1: It's interesting because, like you say, these things are really 955 00:47:30,560 --> 00:47:33,319 Speaker 1: hard to see, like we barely even seen like have 956 00:47:33,560 --> 00:47:35,840 Speaker 1: or have photos of one planet out there beyond the 957 00:47:35,840 --> 00:47:38,560 Speaker 1: Solar System. We kind of have to backtrack what these 958 00:47:38,560 --> 00:47:41,399 Speaker 1: planets look like or how dense they are from what 959 00:47:41,480 --> 00:47:44,279 Speaker 1: we can see of how their stars wiggle, or how 960 00:47:44,400 --> 00:47:46,799 Speaker 1: how much light they block from the star when they 961 00:47:46,920 --> 00:47:48,480 Speaker 1: pass in front of it. Right, it's kind of a 962 00:47:48,480 --> 00:47:51,360 Speaker 1: tricky problem. It's a very tricky problem, and it's amazing 963 00:47:51,480 --> 00:47:53,440 Speaker 1: what we can figure out. You know, you want to 964 00:47:53,440 --> 00:47:55,759 Speaker 1: know what is this planet made out of? When you 965 00:47:55,800 --> 00:47:58,200 Speaker 1: can't go visit it, you can't land a probe on it, 966 00:47:58,280 --> 00:48:01,240 Speaker 1: you can't even really measure the light that comes from 967 00:48:01,320 --> 00:48:03,440 Speaker 1: it very well. So how do you figure out what 968 00:48:03,440 --> 00:48:06,799 Speaker 1: it's made out of? Well, its density is a huge clue. Right, 969 00:48:06,840 --> 00:48:08,880 Speaker 1: If you were an astronomer in a far awayte Solar 970 00:48:08,880 --> 00:48:11,759 Speaker 1: system studying hours and you can measure the density of 971 00:48:11,800 --> 00:48:14,520 Speaker 1: Earth and the density of Jubiter, that would tell you, oh, 972 00:48:14,560 --> 00:48:16,440 Speaker 1: one of those is probably a gas planet, in one 973 00:48:16,440 --> 00:48:18,160 Speaker 1: of those is a rocky planet, because one of them 974 00:48:18,200 --> 00:48:20,920 Speaker 1: is much denser than the others. So just getting a 975 00:48:20,960 --> 00:48:23,360 Speaker 1: measure of the density of planets and other Solar systems 976 00:48:23,560 --> 00:48:26,040 Speaker 1: tells you immediately what kind of things they might be 977 00:48:26,200 --> 00:48:28,160 Speaker 1: made out of. And you're right, it's very tricky, but 978 00:48:28,239 --> 00:48:30,600 Speaker 1: we can measure the mass of those planets and the 979 00:48:30,719 --> 00:48:33,880 Speaker 1: radius of those planets. The mass comes from understanding the 980 00:48:33,960 --> 00:48:36,560 Speaker 1: orbital dynamics, like how long does it take to go 981 00:48:36,600 --> 00:48:39,560 Speaker 1: around the star? How far away from the star is it. 982 00:48:39,840 --> 00:48:42,239 Speaker 1: We can just solve the Newton's equations, you know, use 983 00:48:42,320 --> 00:48:45,360 Speaker 1: Kepler's loss to understand what are the forces of gravity, 984 00:48:45,440 --> 00:48:48,600 Speaker 1: how fast this is going, and therefore how massive is it. 985 00:48:48,680 --> 00:48:50,960 Speaker 1: Just by understanding its orbit, we can tell what the 986 00:48:51,000 --> 00:48:54,840 Speaker 1: mass of the planet is. Like Jupiter, if Jupiter was 987 00:48:54,960 --> 00:48:57,480 Speaker 1: danser or less dense, it would still have the same 988 00:48:57,480 --> 00:49:00,960 Speaker 1: trajectory around the Sun. Exactly, it's mass and it's radius, 989 00:49:01,000 --> 00:49:03,880 Speaker 1: determine the orbital velocity. Or like the Earth, if the 990 00:49:03,960 --> 00:49:08,200 Speaker 1: Earth was fluffier or more hardcore, a year would still 991 00:49:08,239 --> 00:49:11,480 Speaker 1: be a year on Earth. Yeah, exactly because gravity. Exactly, 992 00:49:11,480 --> 00:49:13,880 Speaker 1: Because when you're dealing with Newtonian gravity, you can always 993 00:49:14,080 --> 00:49:16,919 Speaker 1: replace an object with a point particle of the same 994 00:49:17,000 --> 00:49:19,279 Speaker 1: mass and you get an effect the same gravity as 995 00:49:19,320 --> 00:49:21,560 Speaker 1: long as you're on the outside of the object. So 996 00:49:21,680 --> 00:49:24,280 Speaker 1: replace the Earth with a particle the mass of the Earth, 997 00:49:24,480 --> 00:49:27,160 Speaker 1: and it would move the same way the Earth does, right, 998 00:49:27,239 --> 00:49:30,120 Speaker 1: And so by observing the motion of those exoplanets, we 999 00:49:30,160 --> 00:49:32,759 Speaker 1: can tell what their mass is regardless of what their 1000 00:49:32,800 --> 00:49:35,520 Speaker 1: size is, right, it's an independent thing. But then to 1001 00:49:35,560 --> 00:49:37,520 Speaker 1: figure out what their density is, we do need to 1002 00:49:37,560 --> 00:49:40,040 Speaker 1: know what is the size of that planet, and that 1003 00:49:40,160 --> 00:49:43,200 Speaker 1: we can do by watching them eclipse their son. Because 1004 00:49:43,239 --> 00:49:45,640 Speaker 1: you're saying, one way that we can detect those planets 1005 00:49:45,640 --> 00:49:48,360 Speaker 1: are there is that they pass in front of their star, 1006 00:49:48,880 --> 00:49:50,759 Speaker 1: and so they block the light from that star a 1007 00:49:50,880 --> 00:49:53,440 Speaker 1: tiny a little bit. But our telescopes are sensitive enough 1008 00:49:53,480 --> 00:49:56,000 Speaker 1: to see that. It's called the transit method. So as 1009 00:49:56,040 --> 00:49:58,200 Speaker 1: that distant planet passes in front of the star, it 1010 00:49:58,280 --> 00:50:01,040 Speaker 1: decreases the light and decrea the light more if it's 1011 00:50:01,080 --> 00:50:03,600 Speaker 1: a bigger planet, unless if it's a smaller planet. So 1012 00:50:03,680 --> 00:50:06,120 Speaker 1: by seeing how much it decreases the light, we can 1013 00:50:06,160 --> 00:50:08,680 Speaker 1: measure the radius of that planet the size of it, 1014 00:50:09,000 --> 00:50:11,879 Speaker 1: separately from its mass. Right. And once we know their 1015 00:50:11,880 --> 00:50:15,280 Speaker 1: mass and their size, then you can tell their density 1016 00:50:15,360 --> 00:50:17,120 Speaker 1: and that maybe tells you like, hey, this is a 1017 00:50:17,200 --> 00:50:19,800 Speaker 1: rocky planet or an icy planet or a gas planet, 1018 00:50:19,880 --> 00:50:22,360 Speaker 1: right exactly, or it's like, what this is a really 1019 00:50:22,400 --> 00:50:25,560 Speaker 1: weird planet. What's going on? This planet seems to be 1020 00:50:25,560 --> 00:50:28,640 Speaker 1: super fuffy or super dense. This was made out of bread. 1021 00:50:28,840 --> 00:50:32,680 Speaker 1: That's so weird. It's a bad death planet. Maybe the 1022 00:50:32,680 --> 00:50:34,839 Speaker 1: French have been colonizing before we even knew it, but 1023 00:50:34,880 --> 00:50:37,360 Speaker 1: you know, it's definitely going to be testing our assumptions. 1024 00:50:37,360 --> 00:50:40,200 Speaker 1: We have these ideas, these models for how big a 1025 00:50:40,320 --> 00:50:42,640 Speaker 1: rocky planet can be. I'm sure we're gonna find one 1026 00:50:42,680 --> 00:50:44,840 Speaker 1: that breaks that rule if we look far enough, and 1027 00:50:44,880 --> 00:50:47,160 Speaker 1: that's going to tell us something we didn't understand about 1028 00:50:47,160 --> 00:50:49,920 Speaker 1: how planets form. So it's very exciting to look for 1029 00:50:49,960 --> 00:50:53,200 Speaker 1: the extremes of these planets. All right. Well, that means 1030 00:50:53,200 --> 00:50:55,920 Speaker 1: density is an important thing to know about a planet 1031 00:50:55,920 --> 00:50:57,560 Speaker 1: because it tells you a lot about what it's made 1032 00:50:57,560 --> 00:51:00,759 Speaker 1: out of and where in the Solar System, wherever that 1033 00:51:00,760 --> 00:51:03,640 Speaker 1: Solar System might be it came from. Yeah, and so 1034 00:51:03,719 --> 00:51:05,640 Speaker 1: we have been looking and there are a few really 1035 00:51:05,680 --> 00:51:09,120 Speaker 1: fun candidates. One of them is called Kepler one C, 1036 00:51:09,640 --> 00:51:12,239 Speaker 1: which just means that the Kepler telescope discovered it. It's 1037 00:51:12,280 --> 00:51:14,520 Speaker 1: a dred thirty one that it's spotted and this is 1038 00:51:14,640 --> 00:51:17,160 Speaker 1: very uncertain, but this is the planet out there with 1039 00:51:17,239 --> 00:51:20,600 Speaker 1: the highest estimated density. It's more than eight times the 1040 00:51:20,640 --> 00:51:23,440 Speaker 1: mass of the Earth. But it's actually smaller than the 1041 00:51:23,480 --> 00:51:26,680 Speaker 1: Earth in radius, and so the current estimate of this 1042 00:51:26,760 --> 00:51:31,360 Speaker 1: thing density is seventies seven grams per cubic centimeter. Remember 1043 00:51:31,360 --> 00:51:34,719 Speaker 1: the Earth is like five grams per cubic centimeter, So 1044 00:51:34,800 --> 00:51:37,960 Speaker 1: this thing is like fifteen times the density of the 1045 00:51:37,960 --> 00:51:41,000 Speaker 1: Earth if these numbers are correct. Right, But is that 1046 00:51:41,080 --> 00:51:43,799 Speaker 1: weird or is that pretty much what you expect if 1047 00:51:43,920 --> 00:51:46,200 Speaker 1: the Earth was you know, if you gave it eight 1048 00:51:46,239 --> 00:51:49,640 Speaker 1: times the mass and rocks with the Earth also be 1049 00:51:49,680 --> 00:51:51,920 Speaker 1: that size. Yeah, if you took a bunch of Earths 1050 00:51:51,920 --> 00:51:56,200 Speaker 1: and you squeeze them together, you would get something very dense. Right, 1051 00:51:56,200 --> 00:51:58,600 Speaker 1: But we think that it's possible to get larger than 1052 00:51:58,640 --> 00:52:00,680 Speaker 1: the Earth. Remember the upper limits for the radius of 1053 00:52:00,719 --> 00:52:03,600 Speaker 1: a rocky planet it's like ten thousand kilometers and the 1054 00:52:03,600 --> 00:52:06,640 Speaker 1: Earth is six thousand kilometers. So it's possible to get 1055 00:52:06,719 --> 00:52:09,560 Speaker 1: bigger than the Earth. If you plopped a bunch of 1056 00:52:09,600 --> 00:52:11,799 Speaker 1: Earth together, you would expect them to be larger than 1057 00:52:11,840 --> 00:52:13,680 Speaker 1: the Earth by a little bit. So for this to 1058 00:52:13,680 --> 00:52:15,799 Speaker 1: be that dense, it has to also be made of 1059 00:52:15,880 --> 00:52:18,560 Speaker 1: denser stuff than the Earth. So maybe it's just like 1060 00:52:18,680 --> 00:52:21,080 Speaker 1: a huge blob of lead or like has a lot 1061 00:52:21,080 --> 00:52:24,520 Speaker 1: of magnesium or osmium in it. It's not a crazy number, 1062 00:52:24,560 --> 00:52:27,880 Speaker 1: but it's definitely out there on the extreme edge. Whoa 1063 00:52:28,120 --> 00:52:31,319 Speaker 1: like the whole planet just of a single metal or something. Yeah, 1064 00:52:31,480 --> 00:52:35,360 Speaker 1: I know there's fluffy rock that makes it less dense. 1065 00:52:35,480 --> 00:52:38,040 Speaker 1: Maybe it's like an alien engineering project, you know, some 1066 00:52:38,120 --> 00:52:41,400 Speaker 1: alien university, like make a planet out of concrete or 1067 00:52:41,400 --> 00:52:43,840 Speaker 1: make a planet out of osmium or something. Yeah, and 1068 00:52:44,120 --> 00:52:47,840 Speaker 1: see if it floats. And maybe there's a David Letterman 1069 00:52:47,880 --> 00:52:51,000 Speaker 1: in that planet with a very uh big budget for 1070 00:52:51,080 --> 00:52:54,480 Speaker 1: the his or her show exactly. So I hope somebody 1071 00:52:54,480 --> 00:52:56,600 Speaker 1: got an a for that project. And then there's another 1072 00:52:56,600 --> 00:52:59,320 Speaker 1: interesting planet that we found out there, right, So number 1073 00:52:59,360 --> 00:53:03,000 Speaker 1: two on the exo planet density top ten is fifty 1074 00:53:03,040 --> 00:53:07,080 Speaker 1: five can create e This one is six larger than 1075 00:53:07,120 --> 00:53:09,680 Speaker 1: the Earth, so it's a bigger radius, but also about 1076 00:53:09,719 --> 00:53:12,280 Speaker 1: eight times the mass of the Earth, so about twice 1077 00:53:12,400 --> 00:53:15,480 Speaker 1: the density of the Earth, which gives it the density 1078 00:53:15,480 --> 00:53:18,759 Speaker 1: of about lead. You know, that's the average density, which 1079 00:53:18,800 --> 00:53:21,000 Speaker 1: means that probably near the surface it's less dense and 1080 00:53:21,000 --> 00:53:23,360 Speaker 1: in the core it's much much more dense. Um. And 1081 00:53:23,400 --> 00:53:25,600 Speaker 1: it's really fun to think about, like how these planets 1082 00:53:25,600 --> 00:53:28,280 Speaker 1: came to be was there a huge blob of metal 1083 00:53:28,360 --> 00:53:30,920 Speaker 1: that formed a planet, or there are other processes that 1084 00:53:30,960 --> 00:53:34,719 Speaker 1: we don't understand that contribute to planetary formation. You know, 1085 00:53:34,760 --> 00:53:38,879 Speaker 1: we're also able to image protoplanetary disks, like we look 1086 00:53:38,920 --> 00:53:41,359 Speaker 1: far enough back in time, which means looking at things 1087 00:53:41,440 --> 00:53:43,920 Speaker 1: far away, you can see planets form, and we can 1088 00:53:43,920 --> 00:53:47,279 Speaker 1: see stars with disks around them, not just planets. Those 1089 00:53:47,280 --> 00:53:49,600 Speaker 1: are actually easier to spot than planets because the disks 1090 00:53:49,719 --> 00:53:52,279 Speaker 1: discs are much bigger. Well, this one's interesting because it's 1091 00:53:52,320 --> 00:53:54,560 Speaker 1: also eight times the mass of the Earth, but it's 1092 00:53:54,600 --> 00:53:58,000 Speaker 1: only twice the density as opposed to like ten times 1093 00:53:58,000 --> 00:54:00,279 Speaker 1: the density. Yeah, and so it might be made out 1094 00:54:00,280 --> 00:54:02,840 Speaker 1: of less dense stuff. You know, it might have a 1095 00:54:02,880 --> 00:54:05,520 Speaker 1: lot of water in it. We just don't know. Interesting, 1096 00:54:05,560 --> 00:54:07,640 Speaker 1: and we can use some of these facts sometimes to 1097 00:54:07,920 --> 00:54:10,960 Speaker 1: figure out which are maybe habitable planets, right, Like, we 1098 00:54:11,000 --> 00:54:14,520 Speaker 1: don't want to land in a Jupiter or a Saturn 1099 00:54:14,800 --> 00:54:18,920 Speaker 1: because that would be um probably not livable for us. 1100 00:54:19,040 --> 00:54:21,160 Speaker 1: And we don't want to live in a maybe like 1101 00:54:21,160 --> 00:54:24,120 Speaker 1: a Mercury, right, we want to live in a planet 1102 00:54:24,160 --> 00:54:26,560 Speaker 1: maybe that's similar to Earth in density exactly. If you're 1103 00:54:26,560 --> 00:54:29,080 Speaker 1: planning an interstellar road trip, then you probably want to 1104 00:54:29,120 --> 00:54:31,799 Speaker 1: target a rocky planet. It's more likely to have water 1105 00:54:31,960 --> 00:54:33,680 Speaker 1: on the surface of it, for example, to be in 1106 00:54:33,719 --> 00:54:36,360 Speaker 1: what we call the habitable zone. If you're just wondering 1107 00:54:36,400 --> 00:54:38,880 Speaker 1: about what's possible for planets you want. If you're a 1108 00:54:38,920 --> 00:54:41,719 Speaker 1: scientist and you want to visit the craziest planets out there, 1109 00:54:41,800 --> 00:54:43,640 Speaker 1: then yeah, you want to find stuff with really low 1110 00:54:43,680 --> 00:54:46,880 Speaker 1: density or really high density to help inform your models 1111 00:54:47,000 --> 00:54:49,359 Speaker 1: of the universe. But it's amazing how much you can 1112 00:54:49,440 --> 00:54:52,879 Speaker 1: learn about a planet just by understanding its density, right, 1113 00:54:53,239 --> 00:54:57,000 Speaker 1: but then using information that we know from our Solar 1114 00:54:57,040 --> 00:54:59,359 Speaker 1: system to kind of extrapolate and say, hey, that one's 1115 00:54:59,400 --> 00:55:03,080 Speaker 1: probably see or rocky or gassing. Yeah, you're ready. And 1116 00:55:03,200 --> 00:55:05,640 Speaker 1: our knowledge of how these elements work and our models 1117 00:55:05,680 --> 00:55:08,680 Speaker 1: for planetary formation, which come of course from what we've 1118 00:55:08,719 --> 00:55:12,680 Speaker 1: learned in our Solar system. So science good, but you know, 1119 00:55:12,719 --> 00:55:14,880 Speaker 1: I'm sure we're wrong about a lot of how this works. 1120 00:55:14,880 --> 00:55:16,480 Speaker 1: And if we ever do get to visit these solar 1121 00:55:16,480 --> 00:55:19,319 Speaker 1: systems in detail, we will find planets to make us go, what, 1122 00:55:19,480 --> 00:55:22,919 Speaker 1: how is that even possible? We were totally wrong? All right, 1123 00:55:22,960 --> 00:55:25,719 Speaker 1: Well that's kind of a pretty good lesson, I think, 1124 00:55:25,760 --> 00:55:28,200 Speaker 1: as you say of why it's important even to study 1125 00:55:28,200 --> 00:55:30,720 Speaker 1: our backyard, or why it's important to have curiosity about 1126 00:55:30,719 --> 00:55:33,080 Speaker 1: these things, because you know, the more you learn about 1127 00:55:33,080 --> 00:55:36,080 Speaker 1: how solar systems form, and how planets form, and what 1128 00:55:36,239 --> 00:55:39,400 Speaker 1: the terms density, the more you can learn about the 1129 00:55:39,480 --> 00:55:43,759 Speaker 1: rest of the universe with limited information, right, And it 1130 00:55:43,800 --> 00:55:46,879 Speaker 1: tells you something about our own history, which is fascinating 1131 00:55:46,880 --> 00:55:49,880 Speaker 1: in its own right. Something happened early in our solar 1132 00:55:49,880 --> 00:55:53,040 Speaker 1: system to make Earth bigger and more massive than Venus 1133 00:55:53,080 --> 00:55:56,480 Speaker 1: and mercury, and that's why it wins the crown today. 1134 00:55:56,480 --> 00:55:59,320 Speaker 1: All right, Well, that was a pretty dense episode. I 1135 00:55:59,320 --> 00:56:01,520 Speaker 1: guess you can make dancer by playing it twice as 1136 00:56:01,560 --> 00:56:05,719 Speaker 1: fast or increasing the playback speed. You have control over 1137 00:56:05,880 --> 00:56:08,520 Speaker 1: the density of your podcast experience. You know, we often 1138 00:56:08,560 --> 00:56:10,960 Speaker 1: talk about people playing the podcast at higher speeds. I 1139 00:56:10,960 --> 00:56:12,560 Speaker 1: wonder if there are people out there who play us 1140 00:56:12,600 --> 00:56:17,440 Speaker 1: at like half speed to make us more fluffy, you know, 1141 00:56:17,560 --> 00:56:20,600 Speaker 1: like spread it out like butter on toast, you know, right, right, 1142 00:56:20,640 --> 00:56:24,680 Speaker 1: But that would also spread out your chuckles, so it 1143 00:56:24,680 --> 00:56:29,560 Speaker 1: would be more sinister, be more like who I try 1144 00:56:29,560 --> 00:56:32,759 Speaker 1: to make my chuckles pure and innocent. Well, we hope 1145 00:56:32,760 --> 00:56:36,279 Speaker 1: you enjoyed that Thanks for joining us, see you next time. 1146 00:56:44,160 --> 00:56:46,960 Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain 1147 00:56:47,040 --> 00:56:49,880 Speaker 1: the Universe is a production of I heart Radio. For 1148 00:56:50,040 --> 00:56:52,959 Speaker 1: more podcast for my heart Radio, visit the i heart 1149 00:56:53,080 --> 00:56:56,680 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 1150 00:56:56,719 --> 00:57:03,000 Speaker 1: favorite shows. No