1 00:00:08,640 --> 00:00:11,680 Speaker 1: Hey, Daniel, are your kids taller than you? You know 2 00:00:11,800 --> 00:00:14,360 Speaker 1: that day is not too far off. I've only got 3 00:00:14,400 --> 00:00:17,119 Speaker 1: a few inches on my thirteen year old. Oh man, 4 00:00:17,360 --> 00:00:19,360 Speaker 1: that's crazy. How about your parents? Are you taller than 5 00:00:19,440 --> 00:00:22,960 Speaker 1: your parents? I'm like one quarter inch taller than my dad. 6 00:00:24,280 --> 00:00:26,640 Speaker 1: I like how you've measured that precisely. It's like an 7 00:00:26,680 --> 00:00:28,880 Speaker 1: important quarter inch to be taller than your dad. He's 8 00:00:28,920 --> 00:00:32,280 Speaker 1: an engineer, so we pulled out the high precision measurement 9 00:00:32,360 --> 00:00:35,560 Speaker 1: devices when that happened. I wonder if your dad was 10 00:00:35,600 --> 00:00:37,479 Speaker 1: happy that he lost that measurement. But you know, it 11 00:00:37,520 --> 00:00:39,760 Speaker 1: kind of makes me wonder. Do you think stars feel 12 00:00:39,800 --> 00:00:42,360 Speaker 1: the same way new stars have children? Yeah? I mean 13 00:00:42,400 --> 00:00:44,879 Speaker 1: like they have planets, right, Like, do you think they 14 00:00:44,880 --> 00:00:47,559 Speaker 1: would feel proud if their planet was bigger than them? 15 00:00:47,680 --> 00:00:49,600 Speaker 1: Or would they be jealous? I don't know. I just 16 00:00:49,680 --> 00:00:52,160 Speaker 1: hope that one day my own kids escape my orbit 17 00:00:52,200 --> 00:00:55,040 Speaker 1: and start their own solar systems. That's confusing, though, who 18 00:00:55,040 --> 00:01:12,760 Speaker 1: would be the sun? You or your son? Hi am 19 00:01:12,880 --> 00:01:15,880 Speaker 1: or handmade cartoonists and the creator of PhD comics. Hi, 20 00:01:16,000 --> 00:01:18,880 Speaker 1: I'm Daniel. I'm a particle physicist, and I hope my 21 00:01:19,040 --> 00:01:22,119 Speaker 1: kids never move out of the house, and do they 22 00:01:22,160 --> 00:01:26,120 Speaker 1: wish that too? Even after this whole or deal we've 23 00:01:26,120 --> 00:01:27,920 Speaker 1: been through, you still want them in the house. You know. 24 00:01:27,959 --> 00:01:30,480 Speaker 1: It's pretty typical. When they were five or six and 25 00:01:30,520 --> 00:01:32,319 Speaker 1: they learned that kids grow up and move out, they 26 00:01:32,360 --> 00:01:34,480 Speaker 1: were like, what, No, we want to live at home forever. 27 00:01:34,920 --> 00:01:37,840 Speaker 1: But now that they are teens and tweens, they are 28 00:01:38,040 --> 00:01:40,160 Speaker 1: counting the days until they get to move out of 29 00:01:40,160 --> 00:01:43,440 Speaker 1: the house. Wow. But welcome to our podcast Daniel and 30 00:01:43,520 --> 00:01:46,320 Speaker 1: Jorge Explain the Universe, a production of I Heart Radio, 31 00:01:46,480 --> 00:01:48,960 Speaker 1: in which we take you on a tour of everything 32 00:01:49,000 --> 00:01:51,720 Speaker 1: that's amazing and crazy. The big things in the universe, 33 00:01:51,760 --> 00:01:54,240 Speaker 1: the tiny things in the universe, the things that are 34 00:01:54,280 --> 00:01:57,200 Speaker 1: so huge they blow your mind, and the tiny particles 35 00:01:57,240 --> 00:01:59,840 Speaker 1: that are hard to wrap our minds around, and we 36 00:02:00,000 --> 00:02:02,480 Speaker 1: app your mind around all of it. Yeah, a lot 37 00:02:02,480 --> 00:02:05,080 Speaker 1: of wrapping. In this episode, we like to talk about 38 00:02:05,240 --> 00:02:08,640 Speaker 1: all the amazing things out there that is wrapping us basically. 39 00:02:08,720 --> 00:02:14,079 Speaker 1: I mean, we're surrounded by mystery and wonderful and incredible 40 00:02:14,120 --> 00:02:16,359 Speaker 1: things happening in the universe, and we spend a lot 41 00:02:16,360 --> 00:02:19,320 Speaker 1: of time as humans looking out there into the universe 42 00:02:19,320 --> 00:02:21,880 Speaker 1: and trying to understand the way things work, And one 43 00:02:21,960 --> 00:02:24,240 Speaker 1: deep question we have that we're asking all the time 44 00:02:24,440 --> 00:02:27,920 Speaker 1: is whether what we see is typical, whether it's usual, 45 00:02:28,240 --> 00:02:31,880 Speaker 1: or whether there are rule breaking examples out there, whether 46 00:02:31,919 --> 00:02:34,959 Speaker 1: there are other ways the universe could be arranged. Yeah, 47 00:02:35,000 --> 00:02:38,079 Speaker 1: because the universe is full of surprises. And so one 48 00:02:38,080 --> 00:02:41,000 Speaker 1: thing that we've noticed that or that probably as kids 49 00:02:41,040 --> 00:02:43,920 Speaker 1: we know it is about our Solar system, about planets 50 00:02:43,919 --> 00:02:45,960 Speaker 1: and moons, is that there's sort of a like a 51 00:02:46,000 --> 00:02:50,080 Speaker 1: size hierarchy, right, Like you know, suns and stars are 52 00:02:50,080 --> 00:02:53,560 Speaker 1: bigger than planets, and planets are bigger than moons, and 53 00:02:53,639 --> 00:02:58,400 Speaker 1: moons are generally bigger than like asteroids, right, and rocks, yeah, exactly, 54 00:02:58,400 --> 00:03:01,160 Speaker 1: And it goes all the way down to space dust 55 00:03:01,200 --> 00:03:04,040 Speaker 1: that we talked about on a recent episode. It's fascinating 56 00:03:04,080 --> 00:03:06,760 Speaker 1: how our Solar system isn't actually filled with just these 57 00:03:06,800 --> 00:03:10,400 Speaker 1: like different categories of objects, but this whole spectrum of 58 00:03:10,440 --> 00:03:13,160 Speaker 1: objects from the tinies little particles out there all the 59 00:03:13,240 --> 00:03:15,520 Speaker 1: way up to the Sun. But there does seem to 60 00:03:15,520 --> 00:03:18,440 Speaker 1: be sort of an order their stars and planets and 61 00:03:18,520 --> 00:03:20,960 Speaker 1: moons and then all these other little rocks, and so 62 00:03:21,040 --> 00:03:24,280 Speaker 1: it's fun to wonder about whether that order could be 63 00:03:24,440 --> 00:03:27,200 Speaker 1: inverted It'd be kind of weird to think that all 64 00:03:27,280 --> 00:03:30,000 Speaker 1: kids are shorter than their parents, because how would it end. 65 00:03:30,200 --> 00:03:34,679 Speaker 1: It would end with particle children, right, particle sized children, Yeah, 66 00:03:34,760 --> 00:03:38,280 Speaker 1: cork size exactly. It actually seems to be going to 67 00:03:38,280 --> 00:03:40,240 Speaker 1: the other way. A lot of people have kids that 68 00:03:40,240 --> 00:03:42,000 Speaker 1: are taller than them, which means, you know, if you 69 00:03:42,040 --> 00:03:45,280 Speaker 1: extrapolate that eventually children will be the size of stars. 70 00:03:45,440 --> 00:03:49,120 Speaker 1: Oh wow, well my kids are already stars. Daniel in 71 00:03:49,120 --> 00:03:52,680 Speaker 1: my twinkling eyes walked right into that. But I guess 72 00:03:52,680 --> 00:03:55,520 Speaker 1: a big question about the universe and our Solar system 73 00:03:55,680 --> 00:03:58,040 Speaker 1: is does it have to be that way? Do stars 74 00:03:58,120 --> 00:04:00,840 Speaker 1: always have to be bigger than planets and through planets 75 00:04:00,880 --> 00:04:03,640 Speaker 1: always have to be bigger than their moons? And one 76 00:04:03,680 --> 00:04:06,440 Speaker 1: thing that inspired this question in my mind at least, 77 00:04:06,600 --> 00:04:09,960 Speaker 1: was reading about a recent discovery of a really, really 78 00:04:10,040 --> 00:04:13,400 Speaker 1: strange planetary system. There's a planet out there about four 79 00:04:13,440 --> 00:04:16,360 Speaker 1: thousand light years from Earth that was recently discovered and 80 00:04:16,400 --> 00:04:20,080 Speaker 1: confirmed by Hubble. And this planet is huge. It's three 81 00:04:20,200 --> 00:04:24,040 Speaker 1: thousand times the size of the Earth. It's ten times 82 00:04:24,080 --> 00:04:27,440 Speaker 1: the size of Jupiter. This thing is a monster. Wow, 83 00:04:27,760 --> 00:04:30,760 Speaker 1: that is huge. I mean, Jupiter is like the biggest 84 00:04:30,839 --> 00:04:32,800 Speaker 1: kid in our block. You know, now you're saying there's 85 00:04:32,800 --> 00:04:35,400 Speaker 1: a planet that's ten times bigger. Yeah, and it's got 86 00:04:35,400 --> 00:04:39,440 Speaker 1: a moon that's ten times the size of Neptune. So like, 87 00:04:39,520 --> 00:04:42,960 Speaker 1: this moon in this other solar system is bigger than 88 00:04:43,040 --> 00:04:46,400 Speaker 1: most of our planets, because than than us, much bigger 89 00:04:46,400 --> 00:04:49,920 Speaker 1: than Earth. Yes, absolutely, so we are overshadowed by this moon. 90 00:04:49,960 --> 00:04:51,960 Speaker 1: And that got me thinking about the question like, well, 91 00:04:52,520 --> 00:04:55,200 Speaker 1: is it possible to have a planet so big that 92 00:04:55,279 --> 00:04:58,080 Speaker 1: could even be bigger than its own star? Yeah, So 93 00:04:58,160 --> 00:05:00,360 Speaker 1: to be on the program, we'll be asking the Russian 94 00:05:04,920 --> 00:05:09,480 Speaker 1: can planets be bigger than stars? Well? Here about these 95 00:05:09,560 --> 00:05:11,800 Speaker 1: huge planets kind of makes me a little house joke. 96 00:05:12,160 --> 00:05:14,440 Speaker 1: You know. It's like when you see somebody with a 97 00:05:14,440 --> 00:05:16,640 Speaker 1: bigger house, you're like, I wish I had a pool. 98 00:05:16,800 --> 00:05:18,599 Speaker 1: Is that what you think? I think? Man, cleaning that 99 00:05:18,640 --> 00:05:21,480 Speaker 1: pool must be a pain in the butt. Well, it 100 00:05:21,520 --> 00:05:25,080 Speaker 1: would take away time from your that's true, yeah, exactly, 101 00:05:25,200 --> 00:05:27,440 Speaker 1: unless you have lots of couches and lots of different rooms. 102 00:05:27,440 --> 00:05:29,000 Speaker 1: But then you know that feels like a chore, like, 103 00:05:29,000 --> 00:05:30,560 Speaker 1: oh man, I have to sit on that couch and 104 00:05:30,600 --> 00:05:33,599 Speaker 1: nobody's on a miscouch in a while. So did you 105 00:05:33,640 --> 00:05:35,880 Speaker 1: just get a rolling couch. Then you can just scooch 106 00:05:36,000 --> 00:05:38,880 Speaker 1: over to your pool lounge next to the pool while 107 00:05:38,880 --> 00:05:41,360 Speaker 1: you clean it. There's always an engineering solution to you know. 108 00:05:41,520 --> 00:05:44,080 Speaker 1: I'm a big believer in smaller houses actually, so I 109 00:05:44,120 --> 00:05:47,360 Speaker 1: like our cozy little planet. I had some friends actually 110 00:05:47,640 --> 00:05:50,159 Speaker 1: who were on track to getting divorced, and the reason 111 00:05:50,240 --> 00:05:54,400 Speaker 1: was that their house was too big for real, for real, 112 00:05:54,440 --> 00:05:56,479 Speaker 1: because they were always shouting each other from across the 113 00:05:56,520 --> 00:05:58,280 Speaker 1: house and they didn't end up spending time together. And 114 00:05:58,279 --> 00:06:00,279 Speaker 1: they moved into a smaller house where they have to 115 00:06:00,320 --> 00:06:02,920 Speaker 1: share the space and get along, and they actually totally 116 00:06:02,960 --> 00:06:07,560 Speaker 1: improved their marriage. So there's an equals of one study. Well, again, 117 00:06:07,640 --> 00:06:09,760 Speaker 1: I think some engineering solus might have helped. You know, 118 00:06:09,839 --> 00:06:14,080 Speaker 1: there's walking talkies intercoms that could have saved their marriage 119 00:06:14,080 --> 00:06:16,479 Speaker 1: as well, and kept their big house that's too high 120 00:06:16,520 --> 00:06:19,240 Speaker 1: tech and this is much cheaper anyway, Bigger is not 121 00:06:19,320 --> 00:06:22,440 Speaker 1: always better, you know. I like our cozy little planet. Yeah, 122 00:06:22,480 --> 00:06:25,039 Speaker 1: we don't have to shout at each other to talk. 123 00:06:25,520 --> 00:06:28,599 Speaker 1: We have cell phones, dand he and podcasts. Yeah. Well, 124 00:06:28,760 --> 00:06:32,559 Speaker 1: but it's a big question here about bigness and whether 125 00:06:32,640 --> 00:06:35,800 Speaker 1: planets can be bigger than stars. Having a hard time 126 00:06:35,839 --> 00:06:37,720 Speaker 1: wrapping my head around that question. I mean, how could 127 00:06:37,760 --> 00:06:40,760 Speaker 1: have planet be bigger than its star? Or what does 128 00:06:40,760 --> 00:06:44,240 Speaker 1: it even mean to be bigger like dancer size or 129 00:06:44,480 --> 00:06:46,720 Speaker 1: or what? Yeah, lots of fun stuff we will dig 130 00:06:46,760 --> 00:06:49,919 Speaker 1: into in this very episode of our podcast. All right, Well, 131 00:06:50,120 --> 00:06:52,800 Speaker 1: as usual, Daniel went out there into the wild to 132 00:06:52,839 --> 00:06:55,440 Speaker 1: the Internet to ask people if they thought that planets 133 00:06:55,480 --> 00:06:57,680 Speaker 1: could be bigger than stars. And so, if you are 134 00:06:57,720 --> 00:07:00,120 Speaker 1: a denizen of the wilds of the Internet and you 135 00:07:00,160 --> 00:07:03,400 Speaker 1: are waiting for somebody to ask you tough physics questions 136 00:07:03,400 --> 00:07:05,520 Speaker 1: for which you have no time to prepare an answer, 137 00:07:05,880 --> 00:07:09,000 Speaker 1: please write to us two questions at Daniel and Jorge 138 00:07:09,080 --> 00:07:11,640 Speaker 1: dot com and we will send you something. Yeah, I 139 00:07:11,720 --> 00:07:13,520 Speaker 1: think about it for a second. Do you think planets 140 00:07:13,560 --> 00:07:17,040 Speaker 1: can be bigger than stars? Here's what people have to say. Well, 141 00:07:17,080 --> 00:07:20,520 Speaker 1: I would guess it couldn't be bigger, although I would 142 00:07:20,520 --> 00:07:24,240 Speaker 1: also guess that it couldn't be more massive or more 143 00:07:24,840 --> 00:07:28,640 Speaker 1: dense star. I'm thinking about the door star they discovered 144 00:07:28,680 --> 00:07:31,760 Speaker 1: that has a planet. Some planets can be bigger than 145 00:07:31,800 --> 00:07:34,400 Speaker 1: a growth star. So yeah, I think the size of 146 00:07:34,480 --> 00:07:39,440 Speaker 1: stars changes over its lifetime and after it's gotten through 147 00:07:39,480 --> 00:07:43,680 Speaker 1: its red giant phase. Um. There's a few things that 148 00:07:43,680 --> 00:07:47,480 Speaker 1: could happen afterwards, but I think it can ultimately turn 149 00:07:47,520 --> 00:07:50,560 Speaker 1: out to be a much smaller size than it was 150 00:07:50,640 --> 00:07:53,720 Speaker 1: for the majority of his life, and some large gas 151 00:07:53,720 --> 00:07:57,720 Speaker 1: giant far enough away. UM. I think as a chance 152 00:07:57,760 --> 00:08:00,840 Speaker 1: of being larger than its star at a point in time. 153 00:08:01,240 --> 00:08:03,840 Speaker 1: My guess is that if a planet was bigger than 154 00:08:03,880 --> 00:08:07,120 Speaker 1: its star in the sense that its actual mass was 155 00:08:07,240 --> 00:08:10,920 Speaker 1: larger than that of its star, the planet's gravity would 156 00:08:10,960 --> 00:08:14,480 Speaker 1: be bigger than that of the star, and it wouldn't 157 00:08:14,520 --> 00:08:18,880 Speaker 1: really rotate around the star, but would probably form a 158 00:08:19,040 --> 00:08:23,320 Speaker 1: kind of binary system. I think that a planet could 159 00:08:23,320 --> 00:08:26,880 Speaker 1: be bigger than it's sun, but it would have to 160 00:08:26,880 --> 00:08:31,120 Speaker 1: be secluded so that wouldn't pick up other mass. But 161 00:08:31,160 --> 00:08:34,920 Speaker 1: I would also wonder if there could be sustainable life 162 00:08:35,000 --> 00:08:39,119 Speaker 1: on this planet, and also would there be no nighttime 163 00:08:39,240 --> 00:08:41,880 Speaker 1: on this planet? If the Sun is in place of 164 00:08:41,920 --> 00:08:45,440 Speaker 1: the Moon, but the Sun is also spitting around the Earth, 165 00:08:45,960 --> 00:08:50,120 Speaker 1: would it be eternal daytime? All right? Pretty intelligent answers 166 00:08:50,160 --> 00:08:53,280 Speaker 1: here A lot of people digging into the masses of 167 00:08:53,360 --> 00:08:57,160 Speaker 1: things and different kinds of stars that people could orbit 168 00:08:57,440 --> 00:08:59,960 Speaker 1: or that planets could orbit around. A lot of interesting 169 00:09:00,000 --> 00:09:02,480 Speaker 1: answers here. Yeah, a lot of fun speculation. Thank you 170 00:09:02,600 --> 00:09:05,600 Speaker 1: especially to Ryan, our nine year old listener for sharing 171 00:09:05,640 --> 00:09:07,840 Speaker 1: his speculation about what would be like to live on 172 00:09:07,880 --> 00:09:10,840 Speaker 1: such a planet. I love the breadth of ages we 173 00:09:10,880 --> 00:09:14,040 Speaker 1: have in our listening group. Yeah, so I guess let's 174 00:09:14,080 --> 00:09:17,040 Speaker 1: jump into it, Daniel, And let's start what I guess 175 00:09:17,040 --> 00:09:19,559 Speaker 1: with the basic question, which is like, how big could 176 00:09:19,600 --> 00:09:23,240 Speaker 1: planets get? Like, is there a size limited planets? Like? 177 00:09:23,400 --> 00:09:26,320 Speaker 1: Doesn't does it at some point collapse into a star? Yeah? 178 00:09:26,360 --> 00:09:28,760 Speaker 1: This one is not that satisfying because it turns out 179 00:09:28,800 --> 00:09:31,880 Speaker 1: that the definition of a planet, the thing that distinguishes 180 00:09:31,920 --> 00:09:34,760 Speaker 1: something from being a planet and a star, is really 181 00:09:34,760 --> 00:09:37,640 Speaker 1: closely connected to the size, So it's a bit arbitrary. 182 00:09:37,880 --> 00:09:40,800 Speaker 1: And what distinguishes a star from a planet is whether 183 00:09:40,920 --> 00:09:44,040 Speaker 1: or not there is fusion happening inside. Like you've got 184 00:09:44,040 --> 00:09:46,000 Speaker 1: a big blob of stuff but it's just sort of 185 00:09:46,040 --> 00:09:48,520 Speaker 1: sitting there and not fusing. You call that a planet. 186 00:09:48,880 --> 00:09:51,680 Speaker 1: If it's got enough stuff so the collapses and causes 187 00:09:51,760 --> 00:09:54,880 Speaker 1: fusion to happen inside of it, then you call it 188 00:09:54,960 --> 00:09:58,120 Speaker 1: a star. And the thing that controls whether that happens 189 00:09:58,200 --> 00:10:01,040 Speaker 1: is basically the mass of stuff you have, right, like 190 00:10:01,080 --> 00:10:04,080 Speaker 1: the gravity the thing that's compressing all of that mass, 191 00:10:04,080 --> 00:10:07,160 Speaker 1: it might trigger fusion or not. It's not dependent on 192 00:10:07,200 --> 00:10:10,360 Speaker 1: the size of it, right, the physical volume. It only 193 00:10:10,440 --> 00:10:13,640 Speaker 1: depends on the mass. And you do these calculations, and 194 00:10:13,679 --> 00:10:15,520 Speaker 1: you can talk about things in terms of like the 195 00:10:15,559 --> 00:10:19,200 Speaker 1: mass of Jupiter. So Jupiter, for example, doesn't have enough 196 00:10:19,320 --> 00:10:23,000 Speaker 1: stuff to have enough gravity to collapse and cause fusion 197 00:10:23,040 --> 00:10:25,880 Speaker 1: to happen at its core. You need like about ten 198 00:10:26,000 --> 00:10:29,160 Speaker 1: or thirteen times the massive Jupiter to have a special 199 00:10:29,240 --> 00:10:31,400 Speaker 1: kind of star called a brown dwarf, which is a 200 00:10:31,440 --> 00:10:34,800 Speaker 1: special kind of fusion. And so anything up to about 201 00:10:34,880 --> 00:10:38,720 Speaker 1: ten times the massive Jupiter is definitely a planet because 202 00:10:38,720 --> 00:10:41,839 Speaker 1: it can't have fusion inside of it, right, But it doesn't. 203 00:10:41,840 --> 00:10:44,400 Speaker 1: It also depends on what it's made out of. Like 204 00:10:44,920 --> 00:10:47,959 Speaker 1: Jupiter is made mostly out of hydrogen, right, which would 205 00:10:48,200 --> 00:10:50,720 Speaker 1: sort of fuse easily. But if you have something, you know, 206 00:10:50,760 --> 00:10:53,320 Speaker 1: like a giant planet made out of iron, you would 207 00:10:53,360 --> 00:10:56,000 Speaker 1: need a whole lot more to get anything going if 208 00:10:56,120 --> 00:10:58,440 Speaker 1: if you can't all yeah, it does definitely depend on 209 00:10:58,520 --> 00:11:01,800 Speaker 1: the material. But most the stuff in the universe is hydrogen, right, 210 00:11:01,840 --> 00:11:03,520 Speaker 1: So if you're gonna get a blob of stuff and 211 00:11:03,520 --> 00:11:06,040 Speaker 1: cold us it into an object. It's mostly going to 212 00:11:06,160 --> 00:11:09,240 Speaker 1: be hydrogen, but you also are sensitive to the kinds 213 00:11:09,280 --> 00:11:11,720 Speaker 1: of hydrogen you get, Like you can get a brown 214 00:11:11,800 --> 00:11:15,119 Speaker 1: dwarf only under certain conditions. We have the right ratios 215 00:11:15,200 --> 00:11:17,880 Speaker 1: of different isotopes of hydrogen to start a particular kind 216 00:11:17,920 --> 00:11:19,880 Speaker 1: of fusion. To start the kind of fusion we have 217 00:11:19,960 --> 00:11:22,440 Speaker 1: going on in our son, for example, you need basically 218 00:11:22,480 --> 00:11:25,120 Speaker 1: pure hydrogen of the simplest isotope, and then you would 219 00:11:25,120 --> 00:11:27,560 Speaker 1: even need more of it. So how much stuff you 220 00:11:27,600 --> 00:11:30,000 Speaker 1: need to start fusion definitely depends on the amount of 221 00:11:30,080 --> 00:11:31,880 Speaker 1: stuff you have. And you're right, if you just start 222 00:11:31,880 --> 00:11:34,400 Speaker 1: with a blob of iron, the massive hydrogen, that wouldn't 223 00:11:34,440 --> 00:11:37,200 Speaker 1: actually fuse, right, Yeah, because it can. You could have 224 00:11:37,320 --> 00:11:41,040 Speaker 1: like a giant planet made out of iron that it 225 00:11:41,080 --> 00:11:43,400 Speaker 1: could be. You know, the whole size of the galaxy? 226 00:11:43,520 --> 00:11:45,360 Speaker 1: Is that? Is that crazy? Or would that just turn 227 00:11:45,440 --> 00:11:47,720 Speaker 1: into like a neutron star at some point? Wow, the 228 00:11:47,800 --> 00:11:50,280 Speaker 1: size of the galaxy. Oh my gosh, you took like 229 00:11:50,320 --> 00:11:52,559 Speaker 1: all of the iron in the galaxy and blobbed it 230 00:11:52,640 --> 00:11:55,160 Speaker 1: up together into a big planet. Would that start to 231 00:11:55,200 --> 00:11:58,000 Speaker 1: fuse or do other crazy stuff? Yeah? I don't know. 232 00:11:58,080 --> 00:12:00,600 Speaker 1: I don't know anybody's does that calculation. That's really fun. 233 00:12:00,640 --> 00:12:03,440 Speaker 1: It definitely wouldn't fuse, right because, as you say, fusion above, 234 00:12:03,480 --> 00:12:06,800 Speaker 1: iron actually absorbs energy and so it would cool the object, 235 00:12:06,800 --> 00:12:09,640 Speaker 1: and so it wouldn't create fusion. If you get enough 236 00:12:09,880 --> 00:12:13,160 Speaker 1: heavy metal in there, then gravity eventually wins. It'll just 237 00:12:13,240 --> 00:12:16,040 Speaker 1: compress it further and further until it collapses into a 238 00:12:16,080 --> 00:12:18,720 Speaker 1: new drawn star. And if it has even more mass, 239 00:12:18,800 --> 00:12:22,120 Speaker 1: it will become a black hole. So a galaxy sized 240 00:12:22,200 --> 00:12:25,280 Speaker 1: blob of iron would pretty likely turn into a big 241 00:12:25,320 --> 00:12:27,719 Speaker 1: black hole. But in terms of the stuff that we 242 00:12:27,760 --> 00:12:30,400 Speaker 1: actually see out there in the galaxy, the materials that 243 00:12:30,440 --> 00:12:32,960 Speaker 1: are available, most of the stuff out there in the 244 00:12:32,960 --> 00:12:36,040 Speaker 1: galaxy is still hydrogen. You know, we've been slowly cooking 245 00:12:36,120 --> 00:12:39,280 Speaker 1: hydrogen into heavier elements and the inside of stars, but 246 00:12:39,360 --> 00:12:41,920 Speaker 1: it's still a very tiny fraction of the hydrogen in 247 00:12:42,000 --> 00:12:45,079 Speaker 1: the galaxy that's been turned into heavier metals. There's kind 248 00:12:45,080 --> 00:12:47,240 Speaker 1: of an upper limit then, on the mass a planet 249 00:12:47,320 --> 00:12:49,200 Speaker 1: could have, at least in the universe that we see 250 00:12:49,240 --> 00:12:53,320 Speaker 1: not in his imaginary iron field universe. That's right up 251 00:12:53,360 --> 00:12:56,720 Speaker 1: to about you know, ten or fifteen times the massive Jupiter. 252 00:12:56,840 --> 00:12:59,520 Speaker 1: You can still call it a planet. You can arrange 253 00:12:59,520 --> 00:13:01,720 Speaker 1: for other ways to work to get more massive without 254 00:13:01,760 --> 00:13:05,080 Speaker 1: actually fusing, but that's the typical limit. I see anything 255 00:13:05,280 --> 00:13:08,120 Speaker 1: more than fifteen times a massive Jupiter, if it's made 256 00:13:08,120 --> 00:13:10,760 Speaker 1: out of hydrogen, then it's going to start to fuse 257 00:13:10,760 --> 00:13:13,520 Speaker 1: and become a son and it would become a star exactly. 258 00:13:13,520 --> 00:13:15,800 Speaker 1: All right, Well, that's like the mass limit. But we 259 00:13:15,800 --> 00:13:18,160 Speaker 1: we kind of post a question as a bigger can 260 00:13:18,160 --> 00:13:21,160 Speaker 1: a plan and be bigger than stars, in which case 261 00:13:21,440 --> 00:13:23,719 Speaker 1: it can has more to do with the volume, right, 262 00:13:23,760 --> 00:13:26,880 Speaker 1: like the measurement of it the size. Yeah, and this 263 00:13:26,960 --> 00:13:29,360 Speaker 1: is really weird. Like if you took Jupiter and you 264 00:13:29,400 --> 00:13:32,000 Speaker 1: started adding mass to it, you have like a hydrogen pump, 265 00:13:32,040 --> 00:13:34,640 Speaker 1: and you just started dumping hydrogen into Jupiter, then it 266 00:13:34,640 --> 00:13:37,920 Speaker 1: would get more massive, but it wouldn't actually get larger 267 00:13:38,040 --> 00:13:41,400 Speaker 1: very quickly because it would mostly just get denser, Like 268 00:13:41,480 --> 00:13:43,720 Speaker 1: the gravity would get more intense and it would hold 269 00:13:43,760 --> 00:13:46,800 Speaker 1: itself together and it would get denser and denser. So 270 00:13:46,920 --> 00:13:49,559 Speaker 1: as you pump hydrogen into it, you could actually get 271 00:13:49,640 --> 00:13:53,800 Speaker 1: Jupiter up to like seventy times its mass without changing 272 00:13:53,840 --> 00:13:56,480 Speaker 1: its volume very much. You're saying Jupiter right now is 273 00:13:56,520 --> 00:13:58,559 Speaker 1: actually kind of fluffy. I mean a lot of it 274 00:13:58,600 --> 00:14:01,280 Speaker 1: is just like gas right out it is just gas. 275 00:14:01,320 --> 00:14:03,880 Speaker 1: And if you added seventy jupiters and put them all 276 00:14:03,920 --> 00:14:05,959 Speaker 1: on top of each other, they would just like collapse 277 00:14:06,000 --> 00:14:10,040 Speaker 1: to a denser object about the same size as Jupiter. Yeah, 278 00:14:10,080 --> 00:14:12,440 Speaker 1: are there any examples of that? Have we seen? Yeah? 279 00:14:12,440 --> 00:14:14,800 Speaker 1: Actually there's a bunch of them. There's a star out there, 280 00:14:14,840 --> 00:14:18,720 Speaker 1: trappist one A. It's eighty times the massive Jupiter and 281 00:14:18,880 --> 00:14:21,160 Speaker 1: it's a star. Right, so this thing is burning, it's 282 00:14:21,160 --> 00:14:24,120 Speaker 1: a star. It's the same size as Jupiter. Right, So 283 00:14:24,240 --> 00:14:26,640 Speaker 1: right now out there there's a star which is the 284 00:14:26,680 --> 00:14:30,080 Speaker 1: same size as a planet. It's just much much more dense, right, 285 00:14:30,120 --> 00:14:32,600 Speaker 1: This thing is so dense. It's mostly hydrogen, but it's 286 00:14:32,640 --> 00:14:36,640 Speaker 1: like twenty five times as dense as granite. That. Yeah, 287 00:14:36,640 --> 00:14:39,440 Speaker 1: that's crazy to think that hydrogen can be that dense. Yeah, 288 00:14:39,440 --> 00:14:41,680 Speaker 1: they're really weird phases of hydrogen. Als. So when he 289 00:14:41,680 --> 00:14:44,480 Speaker 1: gets so dense, they are these things called like metallic hydrogen, 290 00:14:44,520 --> 00:14:46,240 Speaker 1: and we can dig into that one time in some 291 00:14:46,280 --> 00:14:48,760 Speaker 1: other episode. But there are a bunch of these things, 292 00:14:48,800 --> 00:14:50,920 Speaker 1: Like there's another star out there that's a red dwarf 293 00:14:51,360 --> 00:14:54,480 Speaker 1: and it's about the size of Saturn, and so it's 294 00:14:54,520 --> 00:14:58,760 Speaker 1: actually a star that's smaller, smaller than Jupiter, right, And 295 00:14:58,800 --> 00:15:01,080 Speaker 1: that's just because of these weird effects that as you 296 00:15:01,200 --> 00:15:04,080 Speaker 1: add more volume, the gravity gets more intense, and so 297 00:15:04,120 --> 00:15:07,840 Speaker 1: the planet doesn't actually grow in size. It only grows 298 00:15:07,840 --> 00:15:10,160 Speaker 1: in mass. But it's still a star, meaning it has 299 00:15:10,240 --> 00:15:13,320 Speaker 1: fusion at the center. It's just not exploding maybe like 300 00:15:13,400 --> 00:15:16,440 Speaker 1: our star. And then there are some other examples. You know, 301 00:15:16,480 --> 00:15:18,880 Speaker 1: we say that as you add more mass to the planet, 302 00:15:18,880 --> 00:15:21,400 Speaker 1: it doesn't actually grow in size. That's what we expect 303 00:15:21,480 --> 00:15:23,160 Speaker 1: and that's what we see most of the time, but 304 00:15:23,200 --> 00:15:26,440 Speaker 1: there are some counterexamples that we don't yet understand. Like 305 00:15:26,480 --> 00:15:29,520 Speaker 1: there's a planet out there they found called celt eleven B. 306 00:15:30,000 --> 00:15:32,920 Speaker 1: This is the one they called the styrofoam planet because 307 00:15:33,160 --> 00:15:36,560 Speaker 1: it's one fifth the mass of Jupiter, but it's actually 308 00:15:36,640 --> 00:15:40,560 Speaker 1: like larger than Jupiter. So it's like a big fluffy planet, 309 00:15:40,680 --> 00:15:44,720 Speaker 1: extra fluff. It's like Jupiter exactly. It's like the whipped 310 00:15:44,760 --> 00:15:46,960 Speaker 1: up version. Right. Somebody put a mixer in there and 311 00:15:46,960 --> 00:15:48,560 Speaker 1: set it on high and they're gonna fold it into 312 00:15:48,560 --> 00:15:50,880 Speaker 1: their angel food cake. But this is not something that 313 00:15:50,920 --> 00:15:53,560 Speaker 1: we understand, like it's thought in the models it shouldn't exist, 314 00:15:53,640 --> 00:15:56,200 Speaker 1: and so it tells us that there's something about planetary 315 00:15:56,240 --> 00:15:59,080 Speaker 1: formation we don't understand, or maybe it's some weird thing 316 00:15:59,080 --> 00:16:01,960 Speaker 1: and it just explode, odored and still coalescing. You know, 317 00:16:02,200 --> 00:16:06,040 Speaker 1: a lot of questions there, but mostly we expect that 318 00:16:06,080 --> 00:16:10,400 Speaker 1: you can't get a planet much larger than Jupiter by volume. 319 00:16:10,520 --> 00:16:13,080 Speaker 1: Oh I see, So there is kind of a size 320 00:16:13,120 --> 00:16:17,040 Speaker 1: limit of two planets because if you keep adding more, 321 00:16:17,040 --> 00:16:19,120 Speaker 1: at some point it will stay the same size, but 322 00:16:19,160 --> 00:16:21,600 Speaker 1: at some point it will become a star. So you 323 00:16:21,640 --> 00:16:24,960 Speaker 1: can't have a bigger planet. Yeah, exactly. Roughly, Jupiter is 324 00:16:25,000 --> 00:16:28,320 Speaker 1: about the biggest planet you can make that we understand. 325 00:16:28,520 --> 00:16:31,280 Speaker 1: There's one example out there that the king of planets 326 00:16:31,320 --> 00:16:35,320 Speaker 1: currently is this planet out there h D zero five 327 00:16:35,360 --> 00:16:38,600 Speaker 1: four six b N, which we think has seven times 328 00:16:38,640 --> 00:16:42,360 Speaker 1: the diameter of Jupiter. So this is the largest known planet, 329 00:16:42,520 --> 00:16:44,440 Speaker 1: but it still looks like it's forming, like it's in 330 00:16:44,480 --> 00:16:46,560 Speaker 1: a young solar system, and so it may actually be 331 00:16:46,600 --> 00:16:49,200 Speaker 1: like a brown dwarf that's still sort of coalescing. The 332 00:16:49,200 --> 00:16:54,280 Speaker 1: biggest baby in the universe. It's a big, dangerous baby. 333 00:16:54,320 --> 00:16:58,280 Speaker 1: So careful what you call it. But I guess the 334 00:16:58,520 --> 00:17:02,040 Speaker 1: main point is there's a size limit and a mass 335 00:17:02,080 --> 00:17:04,639 Speaker 1: limit to planets if we sort of stick to what 336 00:17:04,760 --> 00:17:07,679 Speaker 1: we see in the universe, which is mostly hydrogen. But 337 00:17:08,080 --> 00:17:10,720 Speaker 1: I guess the point is that there isn't large enough 338 00:17:10,760 --> 00:17:13,440 Speaker 1: concentrations of the heavier elements to make biger planet. Is 339 00:17:13,480 --> 00:17:15,399 Speaker 1: that kind of yeah? I mean, there might be some 340 00:17:15,520 --> 00:17:19,159 Speaker 1: really big planets out there that fluctuate into having huge 341 00:17:19,200 --> 00:17:21,440 Speaker 1: deposits of rock, but you know there'll be a lot 342 00:17:21,480 --> 00:17:23,879 Speaker 1: of rock. Is a larger rocky core in the center 343 00:17:23,880 --> 00:17:26,800 Speaker 1: of Jupiter than the volume of the Earth, right, So 344 00:17:27,720 --> 00:17:30,439 Speaker 1: typically if you get that large a rocky planet, it's 345 00:17:30,480 --> 00:17:32,679 Speaker 1: also going to have a huge amount of gas around it, 346 00:17:32,960 --> 00:17:35,880 Speaker 1: as you'll end up with the gas planet. All right, well, 347 00:17:35,960 --> 00:17:39,040 Speaker 1: let's get into how the other side of the equation, 348 00:17:39,080 --> 00:17:41,879 Speaker 1: which are the stars? How small can a star get? 349 00:17:42,480 --> 00:17:45,040 Speaker 1: And then we'll talk about the question can a planet 350 00:17:45,119 --> 00:17:48,280 Speaker 1: get bigger than its star? First, let's take a quick break. 351 00:18:00,400 --> 00:18:03,920 Speaker 1: All right, we're talking about planets and stars and their 352 00:18:03,960 --> 00:18:08,679 Speaker 1: relative sizes. Can your kid be bigger than you depends 353 00:18:08,680 --> 00:18:11,160 Speaker 1: on what you feed them. I suppose, yeah, who knows 354 00:18:11,160 --> 00:18:14,280 Speaker 1: what they put in milk these days? But Yeah, we 355 00:18:14,280 --> 00:18:16,520 Speaker 1: talked about planets, and now let's talk about stars, Like, 356 00:18:16,560 --> 00:18:18,960 Speaker 1: what's the smallest size star can get? Because if you 357 00:18:18,960 --> 00:18:21,199 Speaker 1: can have a tiny star but it's pretty heavy, then 358 00:18:21,240 --> 00:18:23,679 Speaker 1: you could imagine it can have a much bigger planet 359 00:18:24,600 --> 00:18:27,000 Speaker 1: orbiting around it. Yeah exactly, We're gonna talk about the 360 00:18:27,000 --> 00:18:29,360 Speaker 1: biggest planet. Now we need to talk about the smallest 361 00:18:29,400 --> 00:18:32,199 Speaker 1: possible star. The thing that's really fascinated about stars is 362 00:18:32,240 --> 00:18:35,320 Speaker 1: that their size depends on where they are in their 363 00:18:35,359 --> 00:18:38,040 Speaker 1: life cycle. Like a star isn't just born and then 364 00:18:38,080 --> 00:18:40,240 Speaker 1: it fizzles out and it always stays the same size. 365 00:18:40,280 --> 00:18:43,280 Speaker 1: It actually evolves a lot. So the size of a star, 366 00:18:43,400 --> 00:18:46,199 Speaker 1: even like our sun, depends on where it is in 367 00:18:46,240 --> 00:18:49,280 Speaker 1: its life cycle. Yeah, it changes size, like it's our 368 00:18:49,359 --> 00:18:51,480 Speaker 1: son is going to get bigger, much bigger at some 369 00:18:51,520 --> 00:18:54,280 Speaker 1: point in the future and then shrink. Yeah exactly. And 370 00:18:54,320 --> 00:18:56,399 Speaker 1: so the way a star is formed is that you 371 00:18:56,600 --> 00:18:59,320 Speaker 1: get a huge blob of gas like hydrogen gas, which 372 00:18:59,680 --> 00:19:02,320 Speaker 1: move to the stuff when you're forming a solar system, 373 00:19:02,400 --> 00:19:05,120 Speaker 1: goes to the Sun because gravity is a runaway process. 374 00:19:05,160 --> 00:19:07,080 Speaker 1: You know, the heaviest thing has the most gravity, so 375 00:19:07,119 --> 00:19:09,200 Speaker 1: it attracts the most stuff, so you get most of 376 00:19:09,240 --> 00:19:12,199 Speaker 1: the hydrogen sort of falling in towards the center of 377 00:19:12,240 --> 00:19:14,600 Speaker 1: the Solar system, and that's how it gets big. Right, 378 00:19:14,640 --> 00:19:16,639 Speaker 1: that's why it doesn't just turn into a planet. It 379 00:19:16,680 --> 00:19:18,960 Speaker 1: turns into a star because it has much more than 380 00:19:19,000 --> 00:19:21,480 Speaker 1: ten or a hundred or even a thousand times the 381 00:19:21,480 --> 00:19:24,040 Speaker 1: mass of Jupiter. And so the early stages of the 382 00:19:24,080 --> 00:19:26,320 Speaker 1: stars that it just gathers all that stuff and then 383 00:19:26,400 --> 00:19:28,760 Speaker 1: fusion happens in the center of the star and that 384 00:19:28,800 --> 00:19:32,199 Speaker 1: pushes back against the gravity. Right, you have gravity pulling 385 00:19:32,240 --> 00:19:35,560 Speaker 1: everything in to form the star and then fusion shining 386 00:19:35,720 --> 00:19:38,960 Speaker 1: energy out and keeping it from collapsing any further. Yeah, 387 00:19:39,040 --> 00:19:40,680 Speaker 1: So then that does that put a limit then to 388 00:19:40,800 --> 00:19:43,440 Speaker 1: how small or how large a star can be. Well, 389 00:19:43,440 --> 00:19:46,000 Speaker 1: in the beginning, it just depends on the mass, Like 390 00:19:46,320 --> 00:19:49,000 Speaker 1: as you add mass to a star, it gets bigger 391 00:19:49,040 --> 00:19:51,879 Speaker 1: and bigger and bigger. And our Sun is actually unusually 392 00:19:51,960 --> 00:19:54,280 Speaker 1: large on average, like most of the stars in the 393 00:19:54,320 --> 00:19:57,200 Speaker 1: galaxy are smaller than our Sun. But there's no limit 394 00:19:57,240 --> 00:20:00,320 Speaker 1: really on the size of a star in this phase, 395 00:20:00,359 --> 00:20:02,240 Speaker 1: Like it can get really really big. And we're gonna 396 00:20:02,240 --> 00:20:05,159 Speaker 1: do a fun podcast episode next week. I think about 397 00:20:05,359 --> 00:20:07,840 Speaker 1: what is the biggest star in the universe. But we're 398 00:20:07,880 --> 00:20:11,000 Speaker 1: interested in the smallest star, right, But what happens when 399 00:20:11,040 --> 00:20:14,639 Speaker 1: a star burns is that fusion pushes all of this 400 00:20:14,680 --> 00:20:16,800 Speaker 1: stuff out. So you get a big star, which causes 401 00:20:16,840 --> 00:20:20,240 Speaker 1: this gravity, which collapses stuff in, and then it causes fusion, 402 00:20:20,240 --> 00:20:22,760 Speaker 1: which works backwards. It's like a back reaction. It pushes 403 00:20:22,800 --> 00:20:25,120 Speaker 1: all the stuff out. It tends to make the star bigger. 404 00:20:25,359 --> 00:20:27,359 Speaker 1: So what happens in the life cycle of the stars 405 00:20:27,400 --> 00:20:29,280 Speaker 1: that it burns for a long time, like billions of 406 00:20:29,359 --> 00:20:32,359 Speaker 1: years depending on its size, and then it grows like, 407 00:20:32,440 --> 00:20:35,600 Speaker 1: as you said, our star is gonna get much much bigger, 408 00:20:35,640 --> 00:20:38,520 Speaker 1: and not like twice as big or three times as big. 409 00:20:38,760 --> 00:20:41,760 Speaker 1: It's gonna be huge. It's gonna grow so much that 410 00:20:41,840 --> 00:20:45,320 Speaker 1: it's radius is going to almost encapsulate the Earth. Yeah, 411 00:20:45,600 --> 00:20:49,880 Speaker 1: there'll be a nice toasty time for Earth if we're 412 00:20:49,920 --> 00:20:52,000 Speaker 1: still here. And this is important to understand in the 413 00:20:52,080 --> 00:20:54,000 Speaker 1: question later about whether or not you're gonna have a 414 00:20:54,000 --> 00:20:57,640 Speaker 1: planet surrounding a star, because before a star gets small, 415 00:20:57,720 --> 00:21:00,679 Speaker 1: it gets really really big, right, And and what happens 416 00:21:00,760 --> 00:21:03,560 Speaker 1: is that it collapses right as you say, what happens 417 00:21:03,560 --> 00:21:05,919 Speaker 1: in fusion is that you're making these heavier metals, and 418 00:21:05,960 --> 00:21:08,080 Speaker 1: so you start out with a blob of hydrogen, but 419 00:21:08,240 --> 00:21:10,800 Speaker 1: soon you have a core of helium which is fused 420 00:21:10,800 --> 00:21:13,440 Speaker 1: from the hydrogen, and then that helium, if the star 421 00:21:13,520 --> 00:21:15,679 Speaker 1: is big enough, burns and the heavier stuff and you 422 00:21:15,760 --> 00:21:18,919 Speaker 1: end up with neon and carbon and oxygen and all 423 00:21:18,920 --> 00:21:21,800 Speaker 1: of this stuff. And so now you have increasing density 424 00:21:21,840 --> 00:21:24,040 Speaker 1: in the center of the star and gravity is sort 425 00:21:24,040 --> 00:21:26,240 Speaker 1: of pulling on it. Again. I love the dynamics of 426 00:21:26,280 --> 00:21:28,919 Speaker 1: star formation and star life cycles because it's this like 427 00:21:28,960 --> 00:21:31,800 Speaker 1: back and forth between fusion that's pushing out on the 428 00:21:31,840 --> 00:21:34,520 Speaker 1: star and gravity that's like trying to collapse it, and 429 00:21:34,560 --> 00:21:37,840 Speaker 1: each one sort of trips itself up, Like gravity causes fusion, 430 00:21:37,880 --> 00:21:40,720 Speaker 1: which pushes stuff out, but then fusion creates denser stuff, 431 00:21:40,720 --> 00:21:44,040 Speaker 1: which increases the gravity. And so eventually what happens is 432 00:21:44,080 --> 00:21:47,000 Speaker 1: that the star collapses because you get so much heavy 433 00:21:47,000 --> 00:21:49,560 Speaker 1: stuff in its center that it can no longer burn. Yeah, 434 00:21:49,600 --> 00:21:53,040 Speaker 1: it's a big drama, like a bit of a dysfunctionnel 435 00:21:53,040 --> 00:21:57,600 Speaker 1: relationship between fusion and gravity. Maybe they should just get 436 00:21:57,600 --> 00:21:59,320 Speaker 1: a smaller house, you know, maybe that would work. A 437 00:21:59,320 --> 00:22:02,960 Speaker 1: smaller universe. Hey, we would all be a lot cozier, 438 00:22:03,720 --> 00:22:06,119 Speaker 1: be like living in the pandemic all the time, forever, 439 00:22:07,359 --> 00:22:09,800 Speaker 1: all right, But I guess it seems like the inevitable 440 00:22:09,800 --> 00:22:12,360 Speaker 1: fate of most stars is to shrink. Like theyll might 441 00:22:12,440 --> 00:22:14,959 Speaker 1: have some heydays where they're huge, but then eventually they 442 00:22:15,000 --> 00:22:18,320 Speaker 1: all shrink because they run out of field. Basically, yeah, exactly, 443 00:22:18,600 --> 00:22:20,840 Speaker 1: they shrink, and what you are left with is some 444 00:22:21,040 --> 00:22:23,639 Speaker 1: really really dense core. Like they blow out a lot 445 00:22:23,720 --> 00:22:25,159 Speaker 1: of the stuff and you get some sort of like 446 00:22:25,480 --> 00:22:28,480 Speaker 1: layers of fluff blown out into the Solar system. But 447 00:22:28,560 --> 00:22:30,399 Speaker 1: at the core, which you're left with, it is a 448 00:22:30,440 --> 00:22:33,560 Speaker 1: few different options. Depending on the mass you started with, 449 00:22:33,800 --> 00:22:36,280 Speaker 1: you might end up with a white dwarf, or a 450 00:22:36,320 --> 00:22:40,480 Speaker 1: neutron star, or actually a black hole. What's a white boar? 451 00:22:40,560 --> 00:22:43,560 Speaker 1: A white dwarf is the future of our Sun. It's 452 00:22:43,560 --> 00:22:47,520 Speaker 1: basically just a huge hot blob of heavy metals, and 453 00:22:47,560 --> 00:22:50,720 Speaker 1: there's no more fusion happening anymore. It's like not big enough, 454 00:22:50,760 --> 00:22:53,920 Speaker 1: there's not enough compression to cause fusion at its core. 455 00:22:54,240 --> 00:22:56,439 Speaker 1: But it's still hot. Right. If you like took a 456 00:22:56,520 --> 00:22:58,840 Speaker 1: scoop out of the center of the Sun and put 457 00:22:58,880 --> 00:23:01,520 Speaker 1: it in space, it still be a big hot blob 458 00:23:01,920 --> 00:23:04,080 Speaker 1: of heavy metals and that's what a white dwarf is. 459 00:23:04,119 --> 00:23:06,760 Speaker 1: It's not glowing anymore because it's making fusion, but it's 460 00:23:06,800 --> 00:23:08,920 Speaker 1: still hot. So they call it a white dwarf because 461 00:23:08,920 --> 00:23:11,600 Speaker 1: it glows from its heat, right, But it's not technically 462 00:23:11,640 --> 00:23:14,719 Speaker 1: a star anymore, right, because there's no fusion. Man, good question, 463 00:23:15,280 --> 00:23:16,960 Speaker 1: is a white dwarf a star? You're right, there's no 464 00:23:17,000 --> 00:23:20,760 Speaker 1: fusion happening anymore. It's like a stellar remnant. It's definitely 465 00:23:20,800 --> 00:23:22,720 Speaker 1: not fusing. But I think you do still call a 466 00:23:22,720 --> 00:23:25,200 Speaker 1: white dwarf a star. Really, but we just said earlier 467 00:23:25,240 --> 00:23:27,920 Speaker 1: that we need a fusion. Daniel, you're confusing me. Oh 468 00:23:27,960 --> 00:23:32,040 Speaker 1: my god, astronomical names are confusing. What news flash? Well, 469 00:23:32,119 --> 00:23:33,840 Speaker 1: it's they call it a star because it's bright and 470 00:23:33,920 --> 00:23:36,920 Speaker 1: it's giving of light right in the form of heat, 471 00:23:37,000 --> 00:23:40,000 Speaker 1: but it's not fusing. It's kind of it's kind of 472 00:23:40,119 --> 00:23:42,040 Speaker 1: somewhere in there. It's somewhere in there. Does it become 473 00:23:42,080 --> 00:23:45,240 Speaker 1: a planet eventually? Eventually? Sort of? What happens is that 474 00:23:45,320 --> 00:23:48,399 Speaker 1: these things eventually cool and they become a black dwarf. 475 00:23:48,920 --> 00:23:50,880 Speaker 1: And a black dwarf is just a white dwarf that's 476 00:23:50,920 --> 00:23:53,800 Speaker 1: had enough time to radiate away its heat into the 477 00:23:53,920 --> 00:23:58,000 Speaker 1: universe and cool from being white hot to be you know, cooler. 478 00:23:58,760 --> 00:24:01,320 Speaker 1: The interesting thing is that there aren't any black dwarks 479 00:24:01,320 --> 00:24:04,520 Speaker 1: in the universe yet because they think it would take 480 00:24:04,560 --> 00:24:07,960 Speaker 1: like trillions of years for a white dwarf to cool off, 481 00:24:08,000 --> 00:24:10,320 Speaker 1: and so there just hasn't been enough time yet to 482 00:24:10,359 --> 00:24:12,320 Speaker 1: form any of these things. I guess they sort of 483 00:24:12,359 --> 00:24:14,560 Speaker 1: become planets, but everyone's too polite to tell them that 484 00:24:14,720 --> 00:24:16,520 Speaker 1: they're no longer a star. You know, it's kind of 485 00:24:16,560 --> 00:24:20,760 Speaker 1: like a professor emeritus. You know, they're not really professors anymore, 486 00:24:20,920 --> 00:24:22,960 Speaker 1: but you know, you don't want to striper way their title, 487 00:24:23,119 --> 00:24:26,280 Speaker 1: yeah exactly, or last decades a list celebrity. They don't 488 00:24:26,280 --> 00:24:28,359 Speaker 1: get invited to the parties anymore, but you know, people's 489 00:24:28,480 --> 00:24:30,560 Speaker 1: last for their autograph. But the amazing thing is that 490 00:24:30,640 --> 00:24:33,320 Speaker 1: you get like six of the mass of the original star, 491 00:24:33,440 --> 00:24:37,000 Speaker 1: but now compacted into an area that's about the volume 492 00:24:37,080 --> 00:24:40,000 Speaker 1: of the Earth. Our sun will be about the size 493 00:24:40,000 --> 00:24:42,359 Speaker 1: of the Earth after all this happens, even though it 494 00:24:42,400 --> 00:24:45,280 Speaker 1: will be much much more dense than the is. It 495 00:24:45,320 --> 00:24:47,560 Speaker 1: sounds tiny, But then there are other possible fates for 496 00:24:47,600 --> 00:24:50,159 Speaker 1: a star, right, not just a wordwarf. That's right, If 497 00:24:50,160 --> 00:24:51,520 Speaker 1: the amount of stuff that you end up in the 498 00:24:51,560 --> 00:24:53,400 Speaker 1: core is large enough that you still have a lot 499 00:24:53,440 --> 00:24:57,480 Speaker 1: of gravitational pressure. You can collapse those heavy metals even 500 00:24:57,520 --> 00:24:59,560 Speaker 1: further and you don't get fusion. What you do is 501 00:24:59,560 --> 00:25:02,800 Speaker 1: you sort of force the electrons and protons together and 502 00:25:02,840 --> 00:25:06,120 Speaker 1: you end up with forming neutrons. It's called electron capture. 503 00:25:06,240 --> 00:25:09,600 Speaker 1: You're like push the electron into the proton and you 504 00:25:09,640 --> 00:25:12,040 Speaker 1: get this interaction in the core that turns all the 505 00:25:12,080 --> 00:25:15,199 Speaker 1: protons and electrons into neutrons, and then you get a 506 00:25:15,280 --> 00:25:19,160 Speaker 1: neutron star. Now, but technically that's also not a star 507 00:25:19,760 --> 00:25:22,080 Speaker 1: because there's no fusion going on anymore. Hold on, I'm 508 00:25:22,119 --> 00:25:24,199 Speaker 1: gonna make sure I have a comprehensive list of your 509 00:25:24,240 --> 00:25:27,879 Speaker 1: objections to astronomical categories so we could submit it to 510 00:25:27,920 --> 00:25:30,560 Speaker 1: the committee. Let's get this straight out, because you're confusing. 511 00:25:30,600 --> 00:25:33,600 Speaker 1: At least one cartoon is here anyway. That's right, Well, 512 00:25:33,640 --> 00:25:35,280 Speaker 1: I have the official form here, so I'll make sure 513 00:25:35,320 --> 00:25:37,320 Speaker 1: to fill it out and submit it after we'dune. But 514 00:25:37,359 --> 00:25:39,920 Speaker 1: you're right, it's a neutron star. It's not fusing, right. 515 00:25:40,280 --> 00:25:43,320 Speaker 1: It's probably still hot like we see neutron stars, but 516 00:25:43,359 --> 00:25:45,960 Speaker 1: they don't emit light in the same way. Mostly we 517 00:25:46,040 --> 00:25:49,480 Speaker 1: see them in the X ray. But these things are 518 00:25:49,680 --> 00:25:52,800 Speaker 1: tiny because they're super duper dense. So you have like 519 00:25:53,040 --> 00:25:55,200 Speaker 1: one and a half times the mass of the Sun, 520 00:25:55,800 --> 00:25:58,439 Speaker 1: and the radius of these things is like ten kilometers. 521 00:25:58,480 --> 00:26:01,679 Speaker 1: It's like a whole star in Los Angeles. Wow. But 522 00:26:01,760 --> 00:26:04,840 Speaker 1: it's amitting light just from its heat or from from 523 00:26:04,880 --> 00:26:06,760 Speaker 1: some kind of process or why are we still giving 524 00:26:06,800 --> 00:26:09,920 Speaker 1: it the honorary title of the star. It's definitely not fusing, 525 00:26:10,440 --> 00:26:12,840 Speaker 1: and so it's giving off light the same way everything 526 00:26:12,880 --> 00:26:15,800 Speaker 1: gives off light that everything with a temperature radiates. It's 527 00:26:15,800 --> 00:26:19,680 Speaker 1: called black body radiation. And all matter that has electromagnetic 528 00:26:19,720 --> 00:26:22,960 Speaker 1: interactions will give off light at some frequency that's connected 529 00:26:23,000 --> 00:26:25,520 Speaker 1: to its temperature. And that's why you know things that 530 00:26:25,640 --> 00:26:28,879 Speaker 1: get hot glow, even things that you don't see glowing 531 00:26:28,920 --> 00:26:32,520 Speaker 1: or are actually glowing just at wavelength that you cannot tell. 532 00:26:33,040 --> 00:26:35,240 Speaker 1: All right, And then a star can also end up 533 00:26:35,240 --> 00:26:38,320 Speaker 1: as a black hole, right, Like if you compress you 534 00:26:38,359 --> 00:26:42,399 Speaker 1: have more mass, even like stronger gravity, it can collapse 535 00:26:42,440 --> 00:26:45,359 Speaker 1: into a black hole. Yeah, exactly. The neutron stars prevented 536 00:26:45,400 --> 00:26:48,120 Speaker 1: from collapsing into a black hole because these neutrons don't 537 00:26:48,160 --> 00:26:50,119 Speaker 1: want to press against each other even further there like 538 00:26:50,200 --> 00:26:53,320 Speaker 1: pushing back. There's some pressure pushing back, but if you 539 00:26:53,359 --> 00:26:55,719 Speaker 1: have enough mass, you can also overcome that. And then 540 00:26:55,720 --> 00:26:58,920 Speaker 1: you get a total gravitational collapse into a black hole. 541 00:26:59,440 --> 00:27:02,480 Speaker 1: And because the things are collapsing right there, even more dense. 542 00:27:02,960 --> 00:27:06,080 Speaker 1: And so from white dwarf to neutron star to black hole, 543 00:27:06,359 --> 00:27:09,520 Speaker 1: the density of matter at the core at least is increasing, 544 00:27:09,520 --> 00:27:12,240 Speaker 1: and so the radius is decreasing, and so these things 545 00:27:12,240 --> 00:27:14,320 Speaker 1: get pretty small. And now you're gonna tell me that 546 00:27:14,359 --> 00:27:17,240 Speaker 1: the black holes also star, Daniel, it's a black hole star? 547 00:27:17,920 --> 00:27:21,680 Speaker 1: Is that the technical term? It's a star of science? 548 00:27:21,720 --> 00:27:24,440 Speaker 1: At least, it's a star of mystery. It's a tell 549 00:27:24,440 --> 00:27:27,440 Speaker 1: our performer out there in space. But yeah, then at 550 00:27:27,480 --> 00:27:29,159 Speaker 1: that point it's no longer star. I mean, come on, 551 00:27:29,200 --> 00:27:31,080 Speaker 1: it's a black hole. A black hole is not a star. 552 00:27:31,160 --> 00:27:33,720 Speaker 1: I think we can definitely rule on that one here today. 553 00:27:33,920 --> 00:27:36,879 Speaker 1: All right, well, let's get into now whether or not 554 00:27:37,080 --> 00:27:40,000 Speaker 1: you could have a planet that's bigger than its star. 555 00:27:40,240 --> 00:27:43,680 Speaker 1: We talked about how big planets get and how small 556 00:27:43,760 --> 00:27:46,920 Speaker 1: stars can get, and how to push the limits of 557 00:27:47,000 --> 00:27:51,320 Speaker 1: what astronomers call things in space. But first let's take 558 00:27:51,320 --> 00:28:06,480 Speaker 1: a quick break. All right, we've set up these two 559 00:28:06,720 --> 00:28:09,520 Speaker 1: topics Daniel, stars and planets, and now we're gonna ask 560 00:28:09,600 --> 00:28:11,920 Speaker 1: can a planet be bigger than its star? I guess 561 00:28:11,960 --> 00:28:14,200 Speaker 1: the question I just remember what we talked about is 562 00:28:14,200 --> 00:28:16,320 Speaker 1: is yes, right. I mean, you can get tiny stars 563 00:28:16,359 --> 00:28:18,919 Speaker 1: and you can get big planets. So there must be 564 00:28:19,000 --> 00:28:21,919 Speaker 1: some point, someplace in the universe where the two are together. 565 00:28:22,160 --> 00:28:25,080 Speaker 1: It certainly seems possible, right, But the key thing is 566 00:28:25,480 --> 00:28:28,439 Speaker 1: can the planet survive? Because the stars tend to be 567 00:28:28,720 --> 00:28:32,320 Speaker 1: large when they're young, then get even larger before they 568 00:28:32,320 --> 00:28:35,639 Speaker 1: get smaller, and so for a planet to outsize its star, 569 00:28:36,040 --> 00:28:39,120 Speaker 1: it has to survive that transition. And that transition is 570 00:28:39,200 --> 00:28:41,680 Speaker 1: not an easy one to survive, right, Like going to 571 00:28:41,720 --> 00:28:44,560 Speaker 1: this red super giant is going to be pretty toasty 572 00:28:44,640 --> 00:28:47,440 Speaker 1: for any inner planets, and the collapse to like a 573 00:28:47,480 --> 00:28:50,520 Speaker 1: black hole or a neutron star can involve a super nova. 574 00:28:50,960 --> 00:28:55,040 Speaker 1: So even if the remnant is smaller than the planet 575 00:28:55,080 --> 00:28:58,400 Speaker 1: originally was, to satisfy sort of say, technically you have 576 00:28:58,480 --> 00:29:01,560 Speaker 1: to survive that transition. You have to make it to 577 00:29:02,000 --> 00:29:04,280 Speaker 1: be bigger than your parents. I guess, I guess you 578 00:29:04,320 --> 00:29:07,240 Speaker 1: have to make it through your parents middle age or something. 579 00:29:08,280 --> 00:29:10,719 Speaker 1: You have to wait it out, wait for them to shrink, 580 00:29:10,760 --> 00:29:13,400 Speaker 1: and then you're taller than your parents. Right exactly when 581 00:29:13,440 --> 00:29:16,920 Speaker 1: their life explodes, if you can somehow hold on, then 582 00:29:18,560 --> 00:29:25,239 Speaker 1: stay away from them. To Jupiter. Yeah, Jupiter, you should go, 583 00:29:25,320 --> 00:29:27,240 Speaker 1: like you know, on a backpacking trip through Europe and 584 00:29:27,480 --> 00:29:29,760 Speaker 1: come back when the Sun has become a white spread. 585 00:29:29,880 --> 00:29:32,200 Speaker 1: Take that job in Asia for sure, and then come back. 586 00:29:33,440 --> 00:29:36,680 Speaker 1: I think that is good parenting advice and good astronomical advice. 587 00:29:36,960 --> 00:29:39,400 Speaker 1: Become a rogue planet at some point in your life, 588 00:29:39,400 --> 00:29:42,920 Speaker 1: you get that tattoo, you know, maybe that's what the 589 00:29:42,920 --> 00:29:44,960 Speaker 1: red spot is on Jupiter. Maybe it's already done his 590 00:29:45,040 --> 00:29:47,960 Speaker 1: traveling man it. Maybe it's a tattoo of the sun. 591 00:29:48,600 --> 00:29:50,800 Speaker 1: You know how some people get like a mom tattoo. 592 00:29:50,920 --> 00:29:54,520 Speaker 1: Maybe that thought it's red, you know, that makes sense. 593 00:29:55,960 --> 00:29:59,640 Speaker 1: We are solving deep, deep questions. An old, old, ancient 594 00:29:59,760 --> 00:30:01,280 Speaker 1: miss the three is about the universe today on the 595 00:30:01,280 --> 00:30:06,560 Speaker 1: podcast Physics and Parenting Podcast. All right, well, um, yeah, 596 00:30:06,560 --> 00:30:08,880 Speaker 1: it's tricky to survive, but it's totally possible, right Like 597 00:30:09,000 --> 00:30:12,160 Speaker 1: Jupiter in our solar system is going to survive our 598 00:30:12,200 --> 00:30:15,239 Speaker 1: sun exploding and becoming a white dwarf right, because it's 599 00:30:15,280 --> 00:30:17,239 Speaker 1: so far away. It is, but you know, it's going 600 00:30:17,280 --> 00:30:20,000 Speaker 1: to be pretty crazy and we're gona lose some of 601 00:30:20,040 --> 00:30:23,240 Speaker 1: the planets, and so it might be that Jupiter doesn't survive. 602 00:30:23,280 --> 00:30:27,120 Speaker 1: Like Jupiter itself won't be disintegrated, but it will be disturbed. 603 00:30:27,440 --> 00:30:30,680 Speaker 1: And so, for example, if Neptune takes off or Saturn 604 00:30:30,720 --> 00:30:33,560 Speaker 1: takes off after the Sun goes white dwarf, and maybe 605 00:30:33,560 --> 00:30:35,880 Speaker 1: that it perturbs the orbit of Jupiter so that it 606 00:30:35,920 --> 00:30:38,360 Speaker 1: also gets flung out into space. Or you need like 607 00:30:38,400 --> 00:30:41,520 Speaker 1: a new stable configuration and things have changed, and some 608 00:30:41,560 --> 00:30:45,200 Speaker 1: of these things are a bit fragile, but it's technically possible, though, 609 00:30:45,200 --> 00:30:46,840 Speaker 1: write like, isn't it kind of hard to kick a 610 00:30:46,920 --> 00:30:49,719 Speaker 1: planet out of Sun's orbit? It's not that easy. But 611 00:30:49,800 --> 00:30:52,000 Speaker 1: one thing that can do it is having your star 612 00:30:52,440 --> 00:30:55,960 Speaker 1: grow to red super giant and push off outer layers, 613 00:30:56,000 --> 00:30:58,400 Speaker 1: and so it totally can happen. And that's because what's 614 00:30:58,520 --> 00:31:01,120 Speaker 1: left of the star when it's shed its layers is 615 00:31:01,240 --> 00:31:04,080 Speaker 1: much smaller than the original star, so it just doesn't 616 00:31:04,160 --> 00:31:07,160 Speaker 1: have the gravity to hold onto the big planets in 617 00:31:07,200 --> 00:31:10,080 Speaker 1: the same orbit. So those planets sort of relax and 618 00:31:10,120 --> 00:31:12,880 Speaker 1: get bigger orbits, and now those orbits are a little 619 00:31:12,920 --> 00:31:16,200 Speaker 1: bit looser and more chaotic, and so they're more susceptible 620 00:31:16,200 --> 00:31:19,040 Speaker 1: to tugs from passing stars that can pull them out 621 00:31:19,040 --> 00:31:21,400 Speaker 1: of their orbits and even out of the Solar system. 622 00:31:21,440 --> 00:31:23,880 Speaker 1: All right, well, it might happen in our Solar system. 623 00:31:23,960 --> 00:31:26,760 Speaker 1: But we have examples of this configuration of a bigger 624 00:31:26,800 --> 00:31:29,000 Speaker 1: planet than its star that we seem like, do we 625 00:31:29,040 --> 00:31:33,560 Speaker 1: have evidence we actually have seen one. Yeah, NASA's telescope tests, 626 00:31:33,600 --> 00:31:36,040 Speaker 1: which is excellent at looking for these things, that has 627 00:31:36,080 --> 00:31:40,160 Speaker 1: spotted this solar system in the constellation Cancer. It's about 628 00:31:40,240 --> 00:31:44,160 Speaker 1: fifteen hundred light years away, and at the center is 629 00:31:44,320 --> 00:31:47,040 Speaker 1: a white dwarf, right, And a white dwarf is something 630 00:31:47,040 --> 00:31:49,200 Speaker 1: which is a stellar remnant, which means that there used 631 00:31:49,240 --> 00:31:52,240 Speaker 1: to be a big, powerful star there which like our Sun, 632 00:31:52,360 --> 00:31:55,000 Speaker 1: burned for a long time billions of years and then 633 00:31:55,040 --> 00:31:58,840 Speaker 1: collapsed into a white dwarf. And around this white dwarf 634 00:31:58,960 --> 00:32:02,600 Speaker 1: they see a planet which is bigger than the white dwarf. 635 00:32:02,720 --> 00:32:05,640 Speaker 1: It is. It's about the size of Neptune. And these 636 00:32:05,640 --> 00:32:07,680 Speaker 1: white dwarfs, you know, they're about the size of a 637 00:32:07,720 --> 00:32:10,400 Speaker 1: small rocky planet like the white dwarf that's in the 638 00:32:10,440 --> 00:32:13,440 Speaker 1: future of our star will be about the volume of Earth, 639 00:32:13,480 --> 00:32:15,800 Speaker 1: and so this one we think is about the same size. 640 00:32:16,440 --> 00:32:19,600 Speaker 1: And so this Earth size star has a planet around 641 00:32:19,640 --> 00:32:22,240 Speaker 1: it that's the size of Neptune. Wow. So that's the 642 00:32:22,280 --> 00:32:25,480 Speaker 1: situation that we're asking about the star with the planet 643 00:32:25,480 --> 00:32:28,120 Speaker 1: that's bigger than flying around. And we've seen these, or 644 00:32:28,160 --> 00:32:31,280 Speaker 1: at least we've detected them using gravity, right, Yeah, exactly, 645 00:32:31,360 --> 00:32:33,600 Speaker 1: we have detected this one. It's sort of weird. We 646 00:32:33,640 --> 00:32:36,720 Speaker 1: don't really understand it. Like the Neptune size planet. It's 647 00:32:36,800 --> 00:32:40,280 Speaker 1: pretty close to the star. It's much closer to the 648 00:32:40,320 --> 00:32:42,960 Speaker 1: star than you would expect because that star must have 649 00:32:43,040 --> 00:32:45,720 Speaker 1: been like a red super giant at some point toasting 650 00:32:45,800 --> 00:32:48,280 Speaker 1: any planet that was near it. And so this planet 651 00:32:48,320 --> 00:32:51,160 Speaker 1: is like inside the radius of where the star should 652 00:32:51,160 --> 00:32:53,600 Speaker 1: have been, and so there must have been some crazy 653 00:32:53,720 --> 00:32:59,320 Speaker 1: gymnastics changing orbital radii after that happened. Oh, I see, 654 00:32:59,360 --> 00:33:02,800 Speaker 1: it's like us surviving the flare up of our sun, Like, 655 00:33:02,880 --> 00:33:05,480 Speaker 1: how could we still be there? Yeah, exactly, And so 656 00:33:05,600 --> 00:33:09,480 Speaker 1: probably this planet was somewhere further out and then something 657 00:33:09,520 --> 00:33:13,320 Speaker 1: crazy happened and it migrated closer. After the planet became 658 00:33:13,360 --> 00:33:15,600 Speaker 1: a white dwarf. So that's sort of like one survival 659 00:33:15,600 --> 00:33:17,600 Speaker 1: strategy is like maybe you don't go all the way 660 00:33:17,600 --> 00:33:19,800 Speaker 1: to Asia, but you just have like a really distant 661 00:33:19,920 --> 00:33:23,880 Speaker 1: orbit and then you come back in closer after then 662 00:33:23,920 --> 00:33:27,200 Speaker 1: you reconnect with your parents after life, move into the city, 663 00:33:27,320 --> 00:33:29,280 Speaker 1: and then you come back to the suburbs, you know, 664 00:33:29,680 --> 00:33:32,120 Speaker 1: when they're ready to retire. All right. So that's one 665 00:33:32,120 --> 00:33:34,600 Speaker 1: example that we've seen. Are there more? That's the only 666 00:33:34,640 --> 00:33:37,040 Speaker 1: one that we've seen. But you know, the fact that 667 00:33:37,080 --> 00:33:40,160 Speaker 1: we've seen this one means that it is possible to 668 00:33:40,320 --> 00:33:44,480 Speaker 1: survive your stars transition to white dwarf for neutron star 669 00:33:45,080 --> 00:33:48,160 Speaker 1: or even black hole, and so it's possible that there 670 00:33:48,200 --> 00:33:50,240 Speaker 1: are a lot of these things out there. It's probably 671 00:33:50,240 --> 00:33:54,120 Speaker 1: pretty common. Yeah. Cool. Well, I feel like we kind 672 00:33:54,120 --> 00:33:57,000 Speaker 1: of cheated a little bit, though, Daniel, because if I 673 00:33:57,040 --> 00:33:59,400 Speaker 1: hold you to the technical definition of a star to 674 00:33:59,400 --> 00:34:01,600 Speaker 1: say that they're as to be fusion in it, it 675 00:34:01,680 --> 00:34:03,600 Speaker 1: sort of becomes a very different question, right, Like, it 676 00:34:03,680 --> 00:34:06,520 Speaker 1: is possible for a white dwarf to have planets that 677 00:34:06,560 --> 00:34:09,120 Speaker 1: are bigger than it, but a white twarf doesn't have 678 00:34:09,160 --> 00:34:11,279 Speaker 1: fusion in it, that's right. A white dwarf doesn't have 679 00:34:11,320 --> 00:34:13,880 Speaker 1: fusion in it, and either does a neutron star. So 680 00:34:13,920 --> 00:34:16,200 Speaker 1: if I hold you to the definition of that we 681 00:34:16,440 --> 00:34:18,759 Speaker 1: post earlier about a star that it has to have 682 00:34:18,800 --> 00:34:21,080 Speaker 1: fusion in it, do you think it's possible still for 683 00:34:21,280 --> 00:34:24,000 Speaker 1: a fusing star to have a planet that's bigger than it. No, 684 00:34:24,080 --> 00:34:26,400 Speaker 1: I don't think so, because a fusing star would have 685 00:34:26,480 --> 00:34:28,480 Speaker 1: to be pretty big, right. You need to be like 686 00:34:28,719 --> 00:34:32,160 Speaker 1: a hundred times the massive Jupiter to get that fusion going, 687 00:34:32,800 --> 00:34:35,600 Speaker 1: and that would eventually be larger than Jupiter. And if 688 00:34:35,640 --> 00:34:39,040 Speaker 1: you had a planet in orbit that was that same size, 689 00:34:39,080 --> 00:34:41,480 Speaker 1: it would also turn into a star. And so what 690 00:34:41,560 --> 00:34:44,040 Speaker 1: you would get then is a binary star system. And 691 00:34:44,040 --> 00:34:46,080 Speaker 1: so it sort of comes just out of this definition 692 00:34:46,120 --> 00:34:48,200 Speaker 1: of what we call a star or a planet. If 693 00:34:48,200 --> 00:34:51,319 Speaker 1: you're gonna have something that's not fusing orbiting around someone 694 00:34:51,360 --> 00:34:53,960 Speaker 1: that is fusing, then the thing that's fusing has got 695 00:34:53,960 --> 00:34:56,440 Speaker 1: to have more mass otherwise it wouldn't be fusing. You 696 00:34:56,520 --> 00:35:01,120 Speaker 1: just confuse me on that last state. So it doesn't 697 00:35:01,120 --> 00:35:03,480 Speaker 1: sound possible, right, because if the star has to be fusing, 698 00:35:03,680 --> 00:35:06,600 Speaker 1: they're usually bigger than the largest planet that you can 699 00:35:06,640 --> 00:35:11,239 Speaker 1: have without fusion. That's what you're saying. You just defused 700 00:35:11,239 --> 00:35:16,759 Speaker 1: the suggestion I diffused this whole podcast apparently, but I 701 00:35:16,760 --> 00:35:19,160 Speaker 1: guess I mean, it's still possible. You just have to 702 00:35:19,239 --> 00:35:22,560 Speaker 1: invert what you call who's orbiting who? Like, you could 703 00:35:23,000 --> 00:35:27,200 Speaker 1: technically have a really heavy planet like it's it's it's 704 00:35:27,239 --> 00:35:29,319 Speaker 1: mostly iron or there's a lot of iron in it, 705 00:35:29,960 --> 00:35:33,400 Speaker 1: so it's very heavy. You could have a star maybe 706 00:35:33,400 --> 00:35:36,279 Speaker 1: that's bigger than it, but it could be that the 707 00:35:36,400 --> 00:35:39,160 Speaker 1: star is orbiting the planet. If the planet had more mass, 708 00:35:39,239 --> 00:35:41,120 Speaker 1: then you could say the star is orbiting the planet. 709 00:35:41,239 --> 00:35:43,400 Speaker 1: You know, in reality, it's not the case that the 710 00:35:43,440 --> 00:35:45,399 Speaker 1: planet is orbiting the star. The two things are sort 711 00:35:45,400 --> 00:35:48,319 Speaker 1: of orbiting each other, and the point that they orbit 712 00:35:48,400 --> 00:35:50,880 Speaker 1: is their center of mass. And typically a star is 713 00:35:50,960 --> 00:35:52,920 Speaker 1: much much heavier than the planet, and so the center 714 00:35:52,920 --> 00:35:54,919 Speaker 1: of mass is close to the center of the star. 715 00:35:55,480 --> 00:35:58,320 Speaker 1: But in a binary star system, the center of masses 716 00:35:58,360 --> 00:36:00,759 Speaker 1: between them, and so they're both orbiting this point that's 717 00:36:00,800 --> 00:36:03,160 Speaker 1: between the two of them. So where that point is 718 00:36:03,160 --> 00:36:06,000 Speaker 1: that their orbiting depends on the relative mass the two objects. 719 00:36:06,000 --> 00:36:08,640 Speaker 1: So yeah, in your fantasy system where you get to 720 00:36:08,640 --> 00:36:11,440 Speaker 1: build up whatever you like, you could make an enormous 721 00:36:11,480 --> 00:36:14,760 Speaker 1: iron planet that has more mass than the star it's using. 722 00:36:14,880 --> 00:36:17,120 Speaker 1: Of course, they would collapse into a black hole, but 723 00:36:17,480 --> 00:36:21,040 Speaker 1: the star would mostly be in orbit around Jorge's black 724 00:36:21,080 --> 00:36:25,560 Speaker 1: hole world. Alright, Well, it sounds like a lot of 725 00:36:25,600 --> 00:36:28,960 Speaker 1: this depends on the definition of a star. If we 726 00:36:29,120 --> 00:36:32,480 Speaker 1: let stars keep their honorific even after they stopped using, 727 00:36:32,520 --> 00:36:34,920 Speaker 1: then it's totally possible for a planet to be bigger 728 00:36:34,920 --> 00:36:37,520 Speaker 1: than a star, because then the star kind of shrinks 729 00:36:37,520 --> 00:36:39,839 Speaker 1: and becomes a door for a neutron star. Yeah, if 730 00:36:39,880 --> 00:36:43,560 Speaker 1: you think professor emeritus are still professors, then a white 731 00:36:43,600 --> 00:36:47,239 Speaker 1: divorf is still a star. But if not, then it's 732 00:36:47,280 --> 00:36:50,239 Speaker 1: technically possible but not likely. Yeah, but sort of just 733 00:36:50,320 --> 00:36:52,560 Speaker 1: by definition, because that's what we call a planet, and 734 00:36:52,560 --> 00:36:56,359 Speaker 1: that's what we call a star. Boy all right, well cool, 735 00:36:56,480 --> 00:36:58,400 Speaker 1: It sounds like the universe still has a lot of 736 00:36:58,440 --> 00:37:03,080 Speaker 1: surprises in store for us, maybe new and interesting configurations 737 00:37:03,080 --> 00:37:04,840 Speaker 1: that we didn't think we're possible. Yeah, and there are 738 00:37:04,880 --> 00:37:07,320 Speaker 1: lots of solar systems out there that we don't understand, 739 00:37:07,440 --> 00:37:11,080 Speaker 1: weird planets made out of styrofoam, and strange stars doing 740 00:37:11,120 --> 00:37:13,680 Speaker 1: things that we don't understand. So this is all based 741 00:37:13,680 --> 00:37:16,680 Speaker 1: on our current understanding of how planets and stars form 742 00:37:16,719 --> 00:37:19,400 Speaker 1: and what's going on inside them. But there are lots 743 00:37:19,400 --> 00:37:22,000 Speaker 1: of surprises out there in the universe, and the only 744 00:37:22,000 --> 00:37:24,200 Speaker 1: way to learn them is to look. And so we 745 00:37:24,239 --> 00:37:27,520 Speaker 1: should all be supporting astronomy and building more space telescopes 746 00:37:27,719 --> 00:37:30,040 Speaker 1: so that we can just sort of buy our way 747 00:37:30,120 --> 00:37:33,520 Speaker 1: into answers to these questions to revealing what's out there 748 00:37:33,520 --> 00:37:35,640 Speaker 1: in the universe. The only way is to look or 749 00:37:35,719 --> 00:37:38,520 Speaker 1: to go out there, which you should tell your kids 750 00:37:38,560 --> 00:37:41,160 Speaker 1: that's an option if they want to become astronauts and 751 00:37:41,200 --> 00:37:43,719 Speaker 1: they can get as far away from you as possible. 752 00:37:43,800 --> 00:37:46,440 Speaker 1: But nobody out there should take this podcast as advice 753 00:37:46,480 --> 00:37:49,120 Speaker 1: that you should get a red spot tattoo by yourself. 754 00:37:49,680 --> 00:37:54,160 Speaker 1: Sure there are people already out there, all right. Well, 755 00:37:54,160 --> 00:37:56,799 Speaker 1: thanks for joining us. We hope you enjoyed that. See 756 00:37:56,800 --> 00:38:06,840 Speaker 1: you next time. Yea, thanks for listening, and remember that 757 00:38:06,960 --> 00:38:09,680 Speaker 1: Daniel and Jorge Explain the Universe is a production of 758 00:38:09,800 --> 00:38:13,160 Speaker 1: I Heart Radio or more podcast for my Heart Radio, 759 00:38:13,320 --> 00:38:16,880 Speaker 1: visit the I Heart Radio Apple Apple Podcasts, or wherever 760 00:38:17,000 --> 00:38:18,680 Speaker 1: you listen to your favorite shows.