1 00:00:08,560 --> 00:00:11,479 Speaker 1: Hey, or hey, you're the go to expert on the 2 00:00:11,560 --> 00:00:15,440 Speaker 1: science of Marvel superheroes. Right, yeah, I'm like Thanos and 3 00:00:15,560 --> 00:00:19,639 Speaker 1: stab my fingers and make half of your questions disappear. Well, 4 00:00:19,680 --> 00:00:23,759 Speaker 1: I'm wondering why iron Man is called iron Man. Isn't 5 00:00:23,800 --> 00:00:26,520 Speaker 1: his suit made of some super high tech material like 6 00:00:26,680 --> 00:00:29,120 Speaker 1: Tony Starkium or something. I'm not sure that's the thing 7 00:00:29,160 --> 00:00:31,880 Speaker 1: in the Marvel universe, but if you look at his 8 00:00:32,080 --> 00:00:34,600 Speaker 1: origin story, you'll see the first suit he made was 9 00:00:34,680 --> 00:00:37,320 Speaker 1: made out of iron. So iron Man is made of 10 00:00:37,360 --> 00:00:40,600 Speaker 1: iron or what? His first suit was made out of iron? 11 00:00:40,600 --> 00:00:42,479 Speaker 1: He made it in a cave, so I guess technically 12 00:00:42,520 --> 00:00:45,680 Speaker 1: he could also be cave Man. So when he upgraded 13 00:00:45,720 --> 00:00:48,520 Speaker 1: his suit to something fancier, they didn't upgrade his name. Also, 14 00:00:49,479 --> 00:00:51,920 Speaker 1: they stuck to the original name. I mean, they're they're 15 00:00:51,920 --> 00:00:54,160 Speaker 1: not all literal, you know, like the Black Widow is 16 00:00:54,200 --> 00:00:57,480 Speaker 1: not actually a spider Captain America is not really a captain. 17 00:00:58,200 --> 00:01:01,640 Speaker 1: He's not really in charge of a Erica what. Also, 18 00:01:01,680 --> 00:01:05,280 Speaker 1: they're not real. Daniel, you're saying there is no science 19 00:01:05,319 --> 00:01:07,759 Speaker 1: in the Marvel universe. There is science, I'm sure, but 20 00:01:07,840 --> 00:01:10,639 Speaker 1: you know it's all fiction. Well, the science will always 21 00:01:10,680 --> 00:01:13,760 Speaker 1: be my superhero and physicists are the villains. Are you 22 00:01:13,760 --> 00:01:16,399 Speaker 1: saying physicists don't actually do physics? We just kept the 23 00:01:16,400 --> 00:01:19,360 Speaker 1: original name after we got upgraded from physicists to villain. 24 00:01:20,600 --> 00:01:38,560 Speaker 1: Maybe you then can be called ironic Man. Hi am 25 00:01:38,680 --> 00:01:41,600 Speaker 1: or Hammack cartoonists and the creator of PhD comics. Hi. 26 00:01:41,720 --> 00:01:44,120 Speaker 1: I'm Daniel. I'm a particle of physicist and a professor 27 00:01:44,160 --> 00:01:46,600 Speaker 1: at U c Irvine, and I really do my best 28 00:01:46,760 --> 00:01:50,480 Speaker 1: to avoid being a supervillain. That doesn't sound good enough, Daniel, 29 00:01:50,520 --> 00:01:52,360 Speaker 1: What do you mean? Don't you know there's no try, 30 00:01:52,440 --> 00:01:54,800 Speaker 1: there's only do you want me to do better than 31 00:01:54,920 --> 00:01:57,800 Speaker 1: my best? That seems like a big ask. I'm saying 32 00:01:57,960 --> 00:02:01,280 Speaker 1: trying not to be a supervillain? Is you know, not 33 00:02:01,320 --> 00:02:04,360 Speaker 1: an excuse for being a supervillain. I'm saying, I'm not 34 00:02:04,560 --> 00:02:07,600 Speaker 1: trying to create weapons that will allow supervillains to destroy 35 00:02:07,640 --> 00:02:09,920 Speaker 1: the world. What else could you ask for me to 36 00:02:10,080 --> 00:02:13,160 Speaker 1: not think about it? I mean it seems pretty obvious, 37 00:02:14,200 --> 00:02:17,040 Speaker 1: But welcome to our podcast Daniel and Jorge Explain the Universe, 38 00:02:17,120 --> 00:02:19,600 Speaker 1: a production of I Heart Radio in which we try 39 00:02:19,680 --> 00:02:22,520 Speaker 1: not to destroy the world, but we do hope to 40 00:02:22,760 --> 00:02:26,760 Speaker 1: break it. Apart into tiny, little understandable pieces. We want 41 00:02:26,800 --> 00:02:30,120 Speaker 1: to cast your minds out into this incredible, glittering cosmos. 42 00:02:30,200 --> 00:02:33,400 Speaker 1: Think about all the amazing and mysterious processes going on 43 00:02:33,639 --> 00:02:36,120 Speaker 1: at the inside of our stars, and the inside of 44 00:02:36,120 --> 00:02:39,440 Speaker 1: our planets, and in the inside of every single object, 45 00:02:39,560 --> 00:02:42,840 Speaker 1: the tiny little buzzing particles that we've together to make 46 00:02:42,960 --> 00:02:45,880 Speaker 1: our cosmos. We want to understand all of it. We 47 00:02:45,919 --> 00:02:48,560 Speaker 1: believe it all somehow makes sense, and we want to 48 00:02:48,600 --> 00:02:50,720 Speaker 1: explain all of it to you. That's right, because it 49 00:02:50,800 --> 00:02:54,960 Speaker 1: is an amazing, uncanny and marvel us universe out there 50 00:02:55,040 --> 00:02:57,160 Speaker 1: for us to explore and to learn about. We love 51 00:02:57,280 --> 00:03:01,080 Speaker 1: wonders and amazing processes going on as we speak all 52 00:03:01,080 --> 00:03:03,400 Speaker 1: the time. Everywhere in the universe, and all of the 53 00:03:03,520 --> 00:03:07,840 Speaker 1: universe is mostly hydrogen, and has always been mostly hydrogen 54 00:03:07,960 --> 00:03:11,840 Speaker 1: since the very beginning. It does contain an interesting smattering 55 00:03:12,000 --> 00:03:16,800 Speaker 1: of other stuff, heavier objects, helium, lithium, beryllium, oxygen, carbon, 56 00:03:17,080 --> 00:03:20,160 Speaker 1: even some iron out there to make the universe a 57 00:03:20,200 --> 00:03:22,520 Speaker 1: little bit spicier. That's right. It would be a little 58 00:03:22,560 --> 00:03:25,519 Speaker 1: bit boring if the whole universe was just hydrogen. Fortunately, 59 00:03:25,560 --> 00:03:27,760 Speaker 1: the universe has figured out a way to make other 60 00:03:27,840 --> 00:03:31,600 Speaker 1: things besides hydrogen, including helium and all of the heavier elements. 61 00:03:31,639 --> 00:03:33,480 Speaker 1: Don't they say, Daniel, that we're all made out of 62 00:03:33,520 --> 00:03:36,280 Speaker 1: star stuff. We are indeed built out of little bits 63 00:03:36,280 --> 00:03:38,920 Speaker 1: that have been assembled on the inside of stars. You 64 00:03:38,960 --> 00:03:41,000 Speaker 1: could think of the whole universe is sort of being 65 00:03:41,200 --> 00:03:44,720 Speaker 1: on fire. It's taking all that hydrogen fuel and trying 66 00:03:44,720 --> 00:03:47,560 Speaker 1: to burn it into heavier stuff. We're sort of put 67 00:03:47,600 --> 00:03:51,640 Speaker 1: together from the ashes of the fires inside stars. Yeah, 68 00:03:51,680 --> 00:03:54,680 Speaker 1: the universe is pretty fire. As the kids say these days, 69 00:03:54,920 --> 00:03:56,920 Speaker 1: it's pretty good. And it's a good thing. It can 70 00:03:56,920 --> 00:03:59,760 Speaker 1: make heavier things other than hydrogen, because that's kind of 71 00:03:59,800 --> 00:04:01,760 Speaker 1: where we come from. That's where plants come from, that's 72 00:04:01,760 --> 00:04:03,960 Speaker 1: where planets come from, that's where all good things to 73 00:04:04,080 --> 00:04:07,160 Speaker 1: humans seem to come from. That's right. Heavier elements allow 74 00:04:07,280 --> 00:04:10,520 Speaker 1: us to make much more complicated and much more interesting things. 75 00:04:10,560 --> 00:04:13,240 Speaker 1: We couldn't have organic life if we didn't have the 76 00:04:13,280 --> 00:04:15,760 Speaker 1: backbone of carbon to allow us to make all of 77 00:04:15,800 --> 00:04:20,240 Speaker 1: those complex molecules. We couldn't breathe. That oxygen wasn't even anything. 78 00:04:20,440 --> 00:04:23,360 Speaker 1: Most of the processes of life rely on biochemistry, which 79 00:04:23,400 --> 00:04:27,040 Speaker 1: rely on heavier atoms than just hydrogen, and so our 80 00:04:27,279 --> 00:04:30,760 Speaker 1: very existence, the existence of intelligence and probably even life, 81 00:04:30,880 --> 00:04:36,080 Speaker 1: relies on stars to convert that hydrogen into heavier interesting stuff. 82 00:04:36,120 --> 00:04:39,240 Speaker 1: But even the awesome power of stars is limited. That's 83 00:04:39,240 --> 00:04:42,200 Speaker 1: the right. We're all born inside of stars, not literally though, 84 00:04:42,320 --> 00:04:45,520 Speaker 1: right like it. Just the heavier elements other than hydrogen 85 00:04:45,560 --> 00:04:47,800 Speaker 1: are made inside of stars, and then they're released out 86 00:04:47,880 --> 00:04:52,320 Speaker 1: into space, into the cosmos when the stars explode. Basically, right, yeah, 87 00:04:52,320 --> 00:04:54,960 Speaker 1: there are these fascinating cycles. When we hear that we 88 00:04:55,000 --> 00:04:56,800 Speaker 1: are made of star stuff, we don't mean that the 89 00:04:56,839 --> 00:04:58,960 Speaker 1: stuff that you and I are made out of was 90 00:04:59,000 --> 00:05:03,200 Speaker 1: formed inside our star. We mean that a previous generation 91 00:05:03,279 --> 00:05:06,640 Speaker 1: of stars, ones that formed and burned for maybe billions 92 00:05:06,680 --> 00:05:10,080 Speaker 1: of years, created the elements that now make us and 93 00:05:10,160 --> 00:05:13,599 Speaker 1: the whole Solar System up. That star burned and then died, 94 00:05:13,680 --> 00:05:17,039 Speaker 1: and then exploded and spread its ingredients out to see 95 00:05:17,080 --> 00:05:20,359 Speaker 1: the next generation of stars. So our Solar system started 96 00:05:20,400 --> 00:05:23,760 Speaker 1: out already enriched in these heavier metals. Of course, our 97 00:05:23,839 --> 00:05:26,599 Speaker 1: sun is busy making even more of them. But all 98 00:05:26,600 --> 00:05:29,120 Speaker 1: the heavy metals and all the non hydrogen stuff that 99 00:05:29,279 --> 00:05:32,080 Speaker 1: is on Earth came from the heart of another star, 100 00:05:32,240 --> 00:05:34,880 Speaker 1: not from our own son, from the corpse of an 101 00:05:34,880 --> 00:05:37,520 Speaker 1: old star, right. I mean, we're sort of like the 102 00:05:37,520 --> 00:05:40,159 Speaker 1: bits and pieces that the old star had made, and 103 00:05:40,200 --> 00:05:42,479 Speaker 1: so we're part of this new generation, Daniel, Are we 104 00:05:42,560 --> 00:05:45,880 Speaker 1: the baby boomers of the Solar system life forms or 105 00:05:45,880 --> 00:05:47,760 Speaker 1: the gen x? I think that's kind of a dark 106 00:05:47,760 --> 00:05:49,680 Speaker 1: way to look at it. The corps of stars. I 107 00:05:49,720 --> 00:05:51,680 Speaker 1: prefer to think of him as ashes of like a 108 00:05:51,760 --> 00:05:53,719 Speaker 1: campfire the end of the night. You don't say my 109 00:05:53,839 --> 00:05:56,480 Speaker 1: campfire has died a grizzly death. You say that it's 110 00:05:56,560 --> 00:05:59,440 Speaker 1: burned out, which doesn't seem like such a negative outcome. 111 00:05:59,600 --> 00:06:02,200 Speaker 1: You say it because you're not the wood and then 112 00:06:02,240 --> 00:06:05,600 Speaker 1: you burn to death. Yeah, exactly, I'm the positive outcome 113 00:06:05,720 --> 00:06:08,840 Speaker 1: of this process. We don't know how many generations of 114 00:06:08,960 --> 00:06:12,599 Speaker 1: stars have been involved in making our stuff. We think that, 115 00:06:12,640 --> 00:06:16,000 Speaker 1: in general, they have been around three generations of stars. 116 00:06:16,120 --> 00:06:19,120 Speaker 1: We call these type one, type two, type three stars 117 00:06:19,160 --> 00:06:22,080 Speaker 1: because we noticed populations of stars that have been around 118 00:06:22,120 --> 00:06:24,479 Speaker 1: for a very very long time, and also populations of 119 00:06:24,480 --> 00:06:26,840 Speaker 1: stars that are sort of younger. But it is possible 120 00:06:26,880 --> 00:06:29,560 Speaker 1: that there were many many generations very early on in 121 00:06:29,600 --> 00:06:32,320 Speaker 1: the universe, when stars were very big and very hot 122 00:06:32,400 --> 00:06:35,440 Speaker 1: and didn't live for very long. Yeah, it's a fascinating 123 00:06:35,440 --> 00:06:38,600 Speaker 1: process the life cycle of stars, but within one life 124 00:06:38,640 --> 00:06:42,200 Speaker 1: cycle of a star, it is pretty busy making stuff. Right. 125 00:06:42,240 --> 00:06:44,880 Speaker 1: It takes hydrogen and combines it to make helium, and 126 00:06:44,920 --> 00:06:47,680 Speaker 1: then it takes helium to combine it into heavier elements, 127 00:06:47,720 --> 00:06:50,599 Speaker 1: and that's how most of the heavier elements are made 128 00:06:50,680 --> 00:06:54,120 Speaker 1: up to a certain point. Yeah, even these stellar fusion 129 00:06:54,240 --> 00:06:57,240 Speaker 1: engines are limited that you can make heavier stuff out 130 00:06:57,240 --> 00:07:00,120 Speaker 1: of lighter stuff, but not forever. You can't take an 131 00:07:00,120 --> 00:07:02,880 Speaker 1: element with like five protons and fuse it together with 132 00:07:02,920 --> 00:07:05,760 Speaker 1: another element of five protons to make something with a 133 00:07:05,800 --> 00:07:08,840 Speaker 1: thousand protons, and its stars are not capable of that. 134 00:07:08,960 --> 00:07:10,920 Speaker 1: As we look around the universe, we notice that there 135 00:07:10,960 --> 00:07:13,480 Speaker 1: seems to be a lot of like iron and nickel 136 00:07:13,760 --> 00:07:16,560 Speaker 1: and this kind of heavy stuff. But above that, heavier 137 00:07:16,600 --> 00:07:20,000 Speaker 1: elements than that are much more rare because stars in 138 00:07:20,040 --> 00:07:23,720 Speaker 1: their fusion process cannot make them. It's right, star fusion 139 00:07:24,000 --> 00:07:27,320 Speaker 1: of materials inside of them is limited up to iron, 140 00:07:27,480 --> 00:07:30,160 Speaker 1: and so that's the heaviest element that a regular sun 141 00:07:30,400 --> 00:07:32,400 Speaker 1: or star can make. And so to be on the 142 00:07:32,400 --> 00:07:40,960 Speaker 1: program will be tackling the question why can't stars fuse 143 00:07:41,240 --> 00:07:45,200 Speaker 1: iron or iron? Men? That is an interesting question. Why 144 00:07:45,200 --> 00:07:49,200 Speaker 1: can't stars fuse iron? They confuse anything lighter than iron, 145 00:07:49,280 --> 00:07:52,480 Speaker 1: but anything heavier than iron they can't do. It provides 146 00:07:52,520 --> 00:07:54,920 Speaker 1: a clue about what's going on at the heart of 147 00:07:54,960 --> 00:07:58,240 Speaker 1: these nuclei, how you build them out of protons and neutrons, 148 00:07:58,280 --> 00:08:01,200 Speaker 1: what the physics is of construct rocking the nucleus of 149 00:08:01,240 --> 00:08:05,000 Speaker 1: an atom, and why something fundamental changes after you get 150 00:08:05,160 --> 00:08:07,640 Speaker 1: to iron. Yeah. So, as usually, we were wondering how 151 00:08:07,640 --> 00:08:10,400 Speaker 1: many people have thought about the limitations of stars and 152 00:08:10,440 --> 00:08:13,880 Speaker 1: why they can't fuse anything heavier than iron. So as 153 00:08:13,960 --> 00:08:15,960 Speaker 1: Usial Daniel went out there to ask people on the 154 00:08:16,000 --> 00:08:18,600 Speaker 1: internet this question. Thank you very much to everybody who 155 00:08:18,680 --> 00:08:21,600 Speaker 1: volunteers for this portion of the podcast. If you'd like 156 00:08:21,640 --> 00:08:24,200 Speaker 1: to hear your voice for our future episodes, please don't 157 00:08:24,200 --> 00:08:26,840 Speaker 1: be shy. Right to me two questions at Angele and 158 00:08:27,000 --> 00:08:29,280 Speaker 1: Jorge dot com and I will set you up. Here's 159 00:08:29,280 --> 00:08:31,800 Speaker 1: what people had to say. The reason why stars can't 160 00:08:31,880 --> 00:08:35,040 Speaker 1: fuse iron is because stars are so hot that iron 161 00:08:35,120 --> 00:08:40,560 Speaker 1: essentially evaporates into something else. It's the electro magnetic forces 162 00:08:40,760 --> 00:08:45,880 Speaker 1: rejecting getting additional positively charged protons coming in, and there 163 00:08:45,920 --> 00:08:49,160 Speaker 1: needs to be more neutrons than that maybe because they 164 00:08:49,200 --> 00:08:52,320 Speaker 1: are not cool enough. Maybe the process of fusing iron 165 00:08:52,600 --> 00:08:57,800 Speaker 1: requires lower temperatures well, simply because it will take an 166 00:08:57,920 --> 00:09:01,680 Speaker 1: insane amount of energy to do it at the well, 167 00:09:01,760 --> 00:09:06,880 Speaker 1: novitabile stars that we know until no are not capable 168 00:09:06,880 --> 00:09:10,360 Speaker 1: of doing this. I actually think they can. But the 169 00:09:10,520 --> 00:09:14,280 Speaker 1: nuclear reaction absorbs more neutrons than it are than it admits, 170 00:09:15,000 --> 00:09:18,840 Speaker 1: and so perpetuating the nuclear actions within a star doesn't 171 00:09:18,840 --> 00:09:22,560 Speaker 1: work if it's fusing iron, whereas everything before iron keeps 172 00:09:22,559 --> 00:09:25,760 Speaker 1: the reaction going. Alright, a lot of interesting reasons here 173 00:09:25,840 --> 00:09:27,600 Speaker 1: or any of these correct. Some of them are sort 174 00:09:27,640 --> 00:09:30,240 Speaker 1: of close to being correct or in the right direction. 175 00:09:30,360 --> 00:09:37,160 Speaker 1: Other ones are pretty much dead wrong, but they're entertaining speculation. Nonetheless, 176 00:09:37,360 --> 00:09:40,840 Speaker 1: you're the physicists, they are not. So it's an interesting question. 177 00:09:40,840 --> 00:09:44,200 Speaker 1: Why can't stars fuse aren't together? And they'd be great. 178 00:09:44,320 --> 00:09:46,920 Speaker 1: They could write, They could make heavier and heavier elements, right, 179 00:09:47,160 --> 00:09:49,640 Speaker 1: m I mean the universe would definitely be different. You 180 00:09:49,720 --> 00:09:52,640 Speaker 1: might have like more uranium and more gold in the universe. 181 00:09:52,679 --> 00:09:54,360 Speaker 1: I don't know if that would be better. You know, 182 00:09:54,360 --> 00:09:56,800 Speaker 1: it might be like more poisonous for life. If you 183 00:09:56,800 --> 00:09:59,400 Speaker 1: start tweaking the basic parameters of the universe. You never 184 00:09:59,440 --> 00:10:01,240 Speaker 1: know what you might end up with. We might all 185 00:10:01,240 --> 00:10:04,040 Speaker 1: be Superman, or we might never have evolved. We might 186 00:10:04,080 --> 00:10:06,720 Speaker 1: all be gold men, is kind of what I'm hearing. 187 00:10:07,160 --> 00:10:09,560 Speaker 1: Might all be a lot shinier and blink out. But 188 00:10:09,559 --> 00:10:11,880 Speaker 1: then gold would be so common it wouldn't even be valuable. 189 00:10:13,400 --> 00:10:17,080 Speaker 1: We'll have to find something else to you know, overprice 190 00:10:18,040 --> 00:10:22,560 Speaker 1: rare comic books. I'm sure the humanity will find something 191 00:10:22,600 --> 00:10:24,719 Speaker 1: to argue about. I have that much faith in us. Well, 192 00:10:24,760 --> 00:10:27,199 Speaker 1: this is a fun question here. Why can't stars fuse? 193 00:10:27,280 --> 00:10:30,160 Speaker 1: Aren't together? And so I guess maybe step us through 194 00:10:30,640 --> 00:10:32,880 Speaker 1: kind of the history of how things get fused together, 195 00:10:32,960 --> 00:10:35,200 Speaker 1: starting from the big bank. You have to understand why 196 00:10:35,360 --> 00:10:38,320 Speaker 1: stars can't fuse iron. We first have to understand what's 197 00:10:38,320 --> 00:10:41,000 Speaker 1: going on when we fuse lighter elements. And you know, 198 00:10:41,080 --> 00:10:44,360 Speaker 1: all the initial ingredients for all of this fusion came 199 00:10:44,480 --> 00:10:47,240 Speaker 1: very very early on in the universe, when the universe 200 00:10:47,320 --> 00:10:51,240 Speaker 1: cooled down and protons were formed, and neutrons were formed, 201 00:10:51,280 --> 00:10:54,120 Speaker 1: and electrons were formed, and they were just flying around 202 00:10:54,320 --> 00:10:57,520 Speaker 1: on their own until it cooled even further, so much 203 00:10:57,520 --> 00:11:00,520 Speaker 1: so that electrons were moving too slow to escape the 204 00:11:00,520 --> 00:11:03,680 Speaker 1: electric attraction of those protons and then they cooled together 205 00:11:03,800 --> 00:11:06,920 Speaker 1: into neutral hydrogen. I guess maybe a question is why 206 00:11:07,000 --> 00:11:10,160 Speaker 1: didn't the Big Bang make heavier things than hydrogen? Like, 207 00:11:10,240 --> 00:11:12,840 Speaker 1: if if things could be made heavier than the hydrogen, 208 00:11:13,120 --> 00:11:15,760 Speaker 1: why did most protons stopped there? If the Big Bang 209 00:11:15,840 --> 00:11:18,199 Speaker 1: was so you know, hot and intense, why didn't heavier 210 00:11:18,280 --> 00:11:20,240 Speaker 1: elements get formed. The short answer is that it just 211 00:11:20,280 --> 00:11:22,920 Speaker 1: didn't really have enough time. Like things were cooling pretty 212 00:11:23,000 --> 00:11:25,440 Speaker 1: rapidly in the Big Bang, and after about ten to 213 00:11:25,480 --> 00:11:29,119 Speaker 1: the minus six seconds we got things like protons and neutrons, 214 00:11:29,200 --> 00:11:32,520 Speaker 1: and those protons are basically hydrogen. There was a little 215 00:11:32,559 --> 00:11:35,360 Speaker 1: bit of helium made during the Big Bang. It was 216 00:11:35,400 --> 00:11:39,000 Speaker 1: hot enough to fuse that hydrogen together into helium, but 217 00:11:39,080 --> 00:11:41,600 Speaker 1: not a whole lot. Wasn't hot for very long. Things 218 00:11:41,679 --> 00:11:45,199 Speaker 1: cooled off very rapidly, and because the next element, lithium 219 00:11:45,440 --> 00:11:48,200 Speaker 1: is very unstable, it doesn't stick around for very long. 220 00:11:48,320 --> 00:11:51,080 Speaker 1: The universe sort of couldn't build up even further during 221 00:11:51,120 --> 00:11:53,920 Speaker 1: the Big Bang. So there's this like initial hot flash 222 00:11:53,960 --> 00:11:56,520 Speaker 1: when hydrogen was made in a little bit of it 223 00:11:56,640 --> 00:11:59,360 Speaker 1: fused into helium, and a tiny little bit was made 224 00:11:59,400 --> 00:12:01,800 Speaker 1: into lithium. But that lithium sort of falls apart, which 225 00:12:01,800 --> 00:12:04,120 Speaker 1: doesn't allow you to then fuse lithium together to make 226 00:12:04,120 --> 00:12:07,720 Speaker 1: heavier stuff. I guess maybe something that some listeners may 227 00:12:07,760 --> 00:12:10,120 Speaker 1: not know is that a hydrogen atom is basically just 228 00:12:10,440 --> 00:12:15,320 Speaker 1: one electron orbiting around one proton, right, And that's exactly right. 229 00:12:15,360 --> 00:12:19,400 Speaker 1: In fact, we call a proton hydrogen. It's like ionized hydrogen, 230 00:12:19,480 --> 00:12:21,240 Speaker 1: even though it really is just a proton. So in 231 00:12:21,240 --> 00:12:23,440 Speaker 1: the beginning of the universe, the protons were formed after 232 00:12:23,520 --> 00:12:26,200 Speaker 1: like ten the minus six seconds, like a millionth of 233 00:12:26,240 --> 00:12:28,360 Speaker 1: a second into the universe, but it took a few 234 00:12:28,440 --> 00:12:31,000 Speaker 1: hundred thousand years before the universe cooled enough that those 235 00:12:31,040 --> 00:12:34,440 Speaker 1: protons could grab onto electron. But we still consider them 236 00:12:34,480 --> 00:12:38,240 Speaker 1: to be hydrogen before they got their electrons, right. Hydrogen 237 00:12:38,320 --> 00:12:40,480 Speaker 1: is kind of like the O G atom, Right, It's 238 00:12:40,520 --> 00:12:43,079 Speaker 1: like the most basic atom you can have, right, because 239 00:12:43,160 --> 00:12:45,600 Speaker 1: if you have just the proton, then that's like, that's 240 00:12:45,640 --> 00:12:48,640 Speaker 1: a hydrogen atom without an electron, is what you're saying. Yeah, 241 00:12:48,679 --> 00:12:51,800 Speaker 1: that's like ionized hydrogen. And so those protons were flying 242 00:12:51,840 --> 00:12:54,600 Speaker 1: around in the very early universe. They were made after 243 00:12:54,640 --> 00:12:57,160 Speaker 1: like ten the minus six seconds, and then things were 244 00:12:57,160 --> 00:13:00,880 Speaker 1: hot enough for like a few minutes. For like three minutes, 245 00:13:01,080 --> 00:13:03,319 Speaker 1: we think things were hot enough for those protons to 246 00:13:03,440 --> 00:13:06,599 Speaker 1: fuse together to make helium. But after that things that 247 00:13:06,720 --> 00:13:09,520 Speaker 1: cooled too much. You didn't have the conditions necessary anymore 248 00:13:09,640 --> 00:13:12,080 Speaker 1: to make heavier stuff. So for like the first three 249 00:13:12,120 --> 00:13:14,400 Speaker 1: minutes of the universe, everything was about as hot and 250 00:13:14,440 --> 00:13:16,920 Speaker 1: dense as the inside of a star. Right, But I 251 00:13:16,960 --> 00:13:20,040 Speaker 1: guess the basic atom of hydrogen, it's just one proton 252 00:13:20,160 --> 00:13:23,120 Speaker 1: with one electron. And now to make heavier elements, you 253 00:13:23,120 --> 00:13:26,440 Speaker 1: have to fuse hydrogen together because the heavier elements have 254 00:13:26,720 --> 00:13:30,959 Speaker 1: extra protons at their nuclei and extra electrons floating around them. 255 00:13:30,960 --> 00:13:33,680 Speaker 1: But it's hard to fuse two protons together, right, because 256 00:13:33,679 --> 00:13:36,959 Speaker 1: they're both positively charged, and so they repel each other, right, 257 00:13:37,000 --> 00:13:39,400 Speaker 1: And so it's hard to make an atom with two 258 00:13:39,440 --> 00:13:42,040 Speaker 1: protons and it's nucleus. Yeah, it is hard to get 259 00:13:42,080 --> 00:13:44,360 Speaker 1: these things together. That's why the universe has to be 260 00:13:44,440 --> 00:13:46,640 Speaker 1: hot and dense for it to happen. But that's why 261 00:13:46,679 --> 00:13:49,120 Speaker 1: it happens at the inside of stars, for example, and 262 00:13:49,200 --> 00:13:51,760 Speaker 1: not just like in a balloon filled with hydrogen. Right. 263 00:13:51,800 --> 00:13:54,720 Speaker 1: The Hindenburg, which was filled with hydrogen, didn't have fusion 264 00:13:54,840 --> 00:13:57,720 Speaker 1: going on inside, because the protons do repel each Other's 265 00:13:57,720 --> 00:14:00,280 Speaker 1: a subtle point there, though, which is the protons appel 266 00:14:00,320 --> 00:14:02,800 Speaker 1: each other because of their positive charges. Once you get 267 00:14:02,800 --> 00:14:05,600 Speaker 1: them close enough, if you happen to squeeze them together, 268 00:14:05,720 --> 00:14:08,800 Speaker 1: then they attract each other because another force takes over, 269 00:14:08,840 --> 00:14:12,600 Speaker 1: the strong force. So at long distances, protons repel each other, 270 00:14:12,679 --> 00:14:14,880 Speaker 1: they avoid getting near each other. If you do manage 271 00:14:14,920 --> 00:14:17,600 Speaker 1: to get them close enough, however, they will stick together 272 00:14:17,760 --> 00:14:20,200 Speaker 1: to make helium. Right, But it takes a lot to 273 00:14:20,240 --> 00:14:23,240 Speaker 1: get them really close together because they are repelling each 274 00:14:23,280 --> 00:14:25,800 Speaker 1: other through the electromagnetic force. And so that's kind of 275 00:14:25,800 --> 00:14:28,040 Speaker 1: where suns come in. Right. If you have a bunch 276 00:14:28,080 --> 00:14:30,840 Speaker 1: of hydrogen out there in space, gravity pulls it all together, 277 00:14:30,960 --> 00:14:34,600 Speaker 1: squeezes those protons close enough, so close together that eventually 278 00:14:34,640 --> 00:14:38,000 Speaker 1: the strong force takes over. Two protons merge, and boom, 279 00:14:38,040 --> 00:14:40,560 Speaker 1: you got a son. You sort of dot dot dotted 280 00:14:40,680 --> 00:14:44,120 Speaker 1: over a few critical elements there, yeada, YadA YadA, Life 281 00:14:44,120 --> 00:14:48,600 Speaker 1: on Earth podcasts, superheroes. Interesting choice of focus. Yeah, and 282 00:14:48,640 --> 00:14:51,280 Speaker 1: so this process is called hydrogen burning. And you might 283 00:14:51,320 --> 00:14:53,800 Speaker 1: imagine that it's just like you said, two hydrogens come 284 00:14:53,840 --> 00:14:56,200 Speaker 1: together to make a helium. Right, that makes sense. Two 285 00:14:56,200 --> 00:14:58,960 Speaker 1: protons come together to make a new nucleus with two 286 00:14:58,960 --> 00:15:02,240 Speaker 1: protons in it. Lilium, though, usually has two protons and 287 00:15:02,440 --> 00:15:05,960 Speaker 1: two neutrons in it. So to actually make a helium nucleus, 288 00:15:06,040 --> 00:15:09,640 Speaker 1: helium four we call it, you need four hydrogen nuclei. 289 00:15:09,680 --> 00:15:13,280 Speaker 1: You need four protons, two of which convert into neutrons 290 00:15:13,360 --> 00:15:16,480 Speaker 1: along the way. So hydrogen burning is actually a multi 291 00:15:16,520 --> 00:15:19,360 Speaker 1: step process. First, you take the two hydrogens, you squeeze 292 00:15:19,400 --> 00:15:22,120 Speaker 1: them together. You don't immediately get helium, which you get 293 00:15:22,160 --> 00:15:25,200 Speaker 1: is deuterium. You get an isotope of hydrogen with a 294 00:15:25,200 --> 00:15:28,160 Speaker 1: proton and a neutron because one of those hydrogens has 295 00:15:28,200 --> 00:15:31,040 Speaker 1: flipped from a proton to a neutron. So now you 296 00:15:31,080 --> 00:15:33,520 Speaker 1: have H two and you take two of those, you 297 00:15:33,520 --> 00:15:37,120 Speaker 1: squeeze those together, and you end up with helium four M. 298 00:15:37,440 --> 00:15:39,120 Speaker 1: But I guess the question is why do you need 299 00:15:39,160 --> 00:15:41,720 Speaker 1: those neutrons to make a stable atom. Why can't you 300 00:15:41,720 --> 00:15:44,120 Speaker 1: just have an atom with two protons in the middle. Remember, 301 00:15:44,200 --> 00:15:47,600 Speaker 1: these protons are positively charged, and they're pushing against each other. 302 00:15:47,720 --> 00:15:51,240 Speaker 1: A neutron is neutral, right, doesn't have any electric charge, 303 00:15:51,360 --> 00:15:53,960 Speaker 1: and so it sort of helps space the protons apart 304 00:15:54,000 --> 00:15:56,880 Speaker 1: from each other. All these objects have little bits of 305 00:15:56,920 --> 00:15:59,800 Speaker 1: the strong force. They all stick together using the strong force. 306 00:16:00,040 --> 00:16:02,080 Speaker 1: Neutrons are there to sort of keep the protons a 307 00:16:02,120 --> 00:16:04,680 Speaker 1: little bit further from each other. But you're saying neutrons 308 00:16:04,800 --> 00:16:07,880 Speaker 1: in our atoms are just filler. They're like what you 309 00:16:07,880 --> 00:16:10,880 Speaker 1: add to meat loaf to make it fluffier and less dense. 310 00:16:11,080 --> 00:16:12,960 Speaker 1: I mean, there's sort of like the palate cleanser, which 311 00:16:13,000 --> 00:16:15,600 Speaker 1: is an important part of any menu. Right. No, no, no, 312 00:16:15,720 --> 00:16:18,320 Speaker 1: you said spacer, which we sounds like filler. They're sort 313 00:16:18,360 --> 00:16:20,400 Speaker 1: of like the therapist in the marriage, right, they keep 314 00:16:20,440 --> 00:16:23,120 Speaker 1: everybody happy. You know. The construction of the nucleus is 315 00:16:23,160 --> 00:16:25,960 Speaker 1: a delicate balance between the strong force, which is trying 316 00:16:25,960 --> 00:16:28,960 Speaker 1: to stick everything together and the electromagnetic force, which in 317 00:16:29,000 --> 00:16:31,160 Speaker 1: the end is pushing things apart. And we'll see as 318 00:16:31,280 --> 00:16:34,400 Speaker 1: nuclei get larger and larger, the balance of power between 319 00:16:34,440 --> 00:16:37,280 Speaker 1: these two things changes because the strong force is only 320 00:16:37,320 --> 00:16:40,480 Speaker 1: powerful over very short distances and the electromagnetic force is 321 00:16:40,520 --> 00:16:44,280 Speaker 1: powerful over longer distances. So you need the neutrons is filler? 322 00:16:44,320 --> 00:16:46,560 Speaker 1: What happens if you take them out when the protons 323 00:16:46,640 --> 00:16:48,680 Speaker 1: much together? Even more if you take them out, then 324 00:16:48,680 --> 00:16:52,400 Speaker 1: the protons get closer and the electrostatic repulsion increases. So 325 00:16:52,520 --> 00:16:55,240 Speaker 1: helium two is not stable if you don't have the neutrons, 326 00:16:55,280 --> 00:16:57,680 Speaker 1: it falls apart. You need the glue, which is sort 327 00:16:57,720 --> 00:16:59,960 Speaker 1: of like the neutrons. All right, Well, that's the beginning 328 00:17:00,120 --> 00:17:03,600 Speaker 1: of merging atoms together to make different materials, and that's 329 00:17:03,640 --> 00:17:06,200 Speaker 1: what's happening inside of Stars. And this goes on and on, 330 00:17:06,280 --> 00:17:09,040 Speaker 1: but at some point it stops ed iron, and so 331 00:17:09,119 --> 00:17:11,800 Speaker 1: let's talk about why that is and what's so special 332 00:17:11,880 --> 00:17:27,359 Speaker 1: about iron. But first let's take a quick break. All Right, 333 00:17:27,400 --> 00:17:30,760 Speaker 1: we're talking about Marvel superheroes and DC superheroes. Is that 334 00:17:30,880 --> 00:17:33,600 Speaker 1: basically what this episode is about. Why can't you use 335 00:17:33,640 --> 00:17:36,320 Speaker 1: Iron Man and Superman? All right? Well, so we talked 336 00:17:36,320 --> 00:17:40,480 Speaker 1: about how inside of Stars heavier elements get me from hydrogen, 337 00:17:40,520 --> 00:17:42,359 Speaker 1: which are the simplest atoms. You can have just a 338 00:17:42,440 --> 00:17:44,920 Speaker 1: proton and an electron and you can make helium out 339 00:17:44,920 --> 00:17:47,720 Speaker 1: of that and you can merge those to make heavier elements. 340 00:17:47,760 --> 00:17:49,919 Speaker 1: But at some point we stop at iron. Somehow stars 341 00:17:49,960 --> 00:17:52,119 Speaker 1: are not able to make iron, Daniel, what's the next 342 00:17:52,160 --> 00:17:54,760 Speaker 1: step after helium? So after helium, you can try to 343 00:17:54,800 --> 00:17:58,000 Speaker 1: make heavier stuff. Lithium and billium, the next elements of 344 00:17:58,000 --> 00:18:00,840 Speaker 1: the periodic table are very very unst able, so you 345 00:18:00,840 --> 00:18:03,560 Speaker 1: can make them inside stars. They just don't last very long, 346 00:18:03,600 --> 00:18:05,600 Speaker 1: so they're not good building blocks for the heavier stuff. 347 00:18:05,640 --> 00:18:07,320 Speaker 1: What do you mean you make it and it dissolves 348 00:18:07,400 --> 00:18:09,920 Speaker 1: right away, or like you make a nucleus of lithium 349 00:18:09,920 --> 00:18:12,320 Speaker 1: and it breaks apart right away. They break apart right away, 350 00:18:12,359 --> 00:18:15,840 Speaker 1: and they're also destroyed by other reactions like photo disintegration. 351 00:18:15,960 --> 00:18:19,720 Speaker 1: Photons made by other reactions tend to break up lithium, beryllium, 352 00:18:19,840 --> 00:18:22,560 Speaker 1: and boron, So they just don't last very long inside 353 00:18:22,560 --> 00:18:25,440 Speaker 1: of stars, so they're not good building blocks for heavier stuff. 354 00:18:26,119 --> 00:18:27,800 Speaker 1: But if they don't last, how do you make stuff 355 00:18:27,840 --> 00:18:30,040 Speaker 1: that's heavier than them? Do you need to skip over them? 356 00:18:30,080 --> 00:18:32,600 Speaker 1: So what you do is you take three helium and 357 00:18:32,640 --> 00:18:36,120 Speaker 1: you combine them to make carbon. Right, carbon his atomic 358 00:18:36,200 --> 00:18:39,600 Speaker 1: number six, So three helium can come together to make carbon. 359 00:18:39,720 --> 00:18:41,840 Speaker 1: It's not an easy thing to do to get the 360 00:18:41,920 --> 00:18:45,200 Speaker 1: three helium to stick together, right, Getting two protons together 361 00:18:45,240 --> 00:18:47,840 Speaker 1: to do hydrogen burning is complicated enough. Now you need 362 00:18:48,000 --> 00:18:51,480 Speaker 1: three things all to dance together. To make carbon requires 363 00:18:51,520 --> 00:18:54,359 Speaker 1: a very hot, very dense kind of sun. Well, I 364 00:18:54,400 --> 00:18:57,560 Speaker 1: mean it seems hard to make helium in the first place. Right, 365 00:18:57,640 --> 00:19:00,600 Speaker 1: you said you need four hydrogen atoms to make a lilium, 366 00:19:00,600 --> 00:19:02,840 Speaker 1: You do, you need four hydrogen atoms, and so inside 367 00:19:02,880 --> 00:19:05,000 Speaker 1: the sun, these four things have to be kind of 368 00:19:05,119 --> 00:19:07,479 Speaker 1: a collision course with each other. Now, the steps are 369 00:19:07,480 --> 00:19:10,399 Speaker 1: sort of independent. You have two hydrogen atoms come together 370 00:19:10,440 --> 00:19:12,840 Speaker 1: to make deuterium, which is a proton and a neutron 371 00:19:12,960 --> 00:19:16,040 Speaker 1: that bangs together with another hydrogen to make helium three, 372 00:19:16,119 --> 00:19:19,160 Speaker 1: and then the helium three's together combined to make helium 373 00:19:19,160 --> 00:19:22,000 Speaker 1: four and give off some more protons. All those steps 374 00:19:22,000 --> 00:19:25,040 Speaker 1: are independent, and the intermediate pieces are more stable, so 375 00:19:25,080 --> 00:19:28,000 Speaker 1: it's not as unlikely as requiring four things to all 376 00:19:28,040 --> 00:19:30,560 Speaker 1: come together at once. But to form carbon, you do 377 00:19:30,640 --> 00:19:33,960 Speaker 1: need three helium nuclear to come together pretty quickly, because 378 00:19:33,960 --> 00:19:36,560 Speaker 1: two helium come together to make berrillium, which is really 379 00:19:36,560 --> 00:19:38,920 Speaker 1: not stable for very long, and you need that third 380 00:19:38,960 --> 00:19:41,440 Speaker 1: helium to come in and turn it into carbon before 381 00:19:41,520 --> 00:19:44,920 Speaker 1: the berrillium falls apart. WHOA. So literally, inside the sun 382 00:19:45,200 --> 00:19:48,159 Speaker 1: you need to have three helium atoms like chance, just 383 00:19:48,200 --> 00:19:51,280 Speaker 1: beyond a collision courts with each other, or inside of stars. 384 00:19:51,280 --> 00:19:54,080 Speaker 1: Does this happen like by squeezing. It's a less kind 385 00:19:54,080 --> 00:19:57,000 Speaker 1: of an explosion. It's more like things get squeezed together. Yeah, 386 00:19:57,000 --> 00:19:59,480 Speaker 1: things are getting squeezed together. It's the density, right, the 387 00:19:59,520 --> 00:20:02,000 Speaker 1: pressure that's creating the possibility for this to happen. You 388 00:20:02,040 --> 00:20:05,040 Speaker 1: need like a certain number of helium atoms per cubic 389 00:20:05,119 --> 00:20:09,040 Speaker 1: centimeter to make the probabilities anything greater than basically zero. Right. 390 00:20:09,080 --> 00:20:11,679 Speaker 1: So inside of suns, the gravity squeezing stuff together, it 391 00:20:11,720 --> 00:20:16,479 Speaker 1: creates these reactions. You make heavier elements, and that releases energy, 392 00:20:16,640 --> 00:20:18,800 Speaker 1: because that's kind of how suns work, right, They squeeze 393 00:20:18,840 --> 00:20:21,439 Speaker 1: in together. Once they pop into place, once they merge, 394 00:20:21,480 --> 00:20:24,600 Speaker 1: they snap together, a bunch of energies released, and that's 395 00:20:24,720 --> 00:20:27,120 Speaker 1: the energy of the sun. Yeah, that's the crucial thing 396 00:20:27,160 --> 00:20:29,720 Speaker 1: we haven't talked about yet. When you combine hydrogen together 397 00:20:29,800 --> 00:20:32,440 Speaker 1: to make helium, you don't just get helium. You also 398 00:20:32,560 --> 00:20:35,879 Speaker 1: give off photons, give off neutrinos as well. But energy 399 00:20:36,000 --> 00:20:38,680 Speaker 1: is released when you do this reaction, and that helps 400 00:20:38,720 --> 00:20:40,960 Speaker 1: create the conditions for the next reaction. It makes the 401 00:20:41,000 --> 00:20:43,400 Speaker 1: core of the sun very, very hot, and so this 402 00:20:43,480 --> 00:20:45,199 Speaker 1: is just sort of like a fire the way like 403 00:20:45,280 --> 00:20:47,399 Speaker 1: when you start a log burning, it helps create the 404 00:20:47,400 --> 00:20:49,920 Speaker 1: conditions for the next log to burn because it creates 405 00:20:49,960 --> 00:20:52,320 Speaker 1: that heat which will look nite the next log. So 406 00:20:52,440 --> 00:20:55,360 Speaker 1: in plasma physics they call this ignition when the plasma 407 00:20:55,480 --> 00:20:58,160 Speaker 1: is hot enough to create fusion, and that fusion then 408 00:20:58,359 --> 00:21:01,080 Speaker 1: maintains the heat of the alasthma. The fact that these 409 00:21:01,080 --> 00:21:04,359 Speaker 1: reactions release heat is what allows them to continue to 410 00:21:04,400 --> 00:21:06,880 Speaker 1: go and also what warms up our summers. Yeah, it's 411 00:21:06,880 --> 00:21:11,200 Speaker 1: interesting because it's like merging atoms together is what releases 412 00:21:11,200 --> 00:21:13,960 Speaker 1: the energy, which is i think maybe a little counterintuitive 413 00:21:13,960 --> 00:21:15,879 Speaker 1: for most people because we're sort of used to like 414 00:21:16,119 --> 00:21:20,000 Speaker 1: breaking things to release energy, right, Like we're to associating 415 00:21:20,040 --> 00:21:23,000 Speaker 1: a huge release of energy with like an explosion something breaking, 416 00:21:23,080 --> 00:21:25,400 Speaker 1: But it's this is the opposite. Actually, when you put 417 00:21:25,440 --> 00:21:28,600 Speaker 1: things together, it releases energy when you immerge them. It's 418 00:21:28,640 --> 00:21:30,600 Speaker 1: like taking two piece of clay and somehow when you 419 00:21:30,640 --> 00:21:33,880 Speaker 1: stick them together that releases a bunch of light. Yeah, 420 00:21:33,960 --> 00:21:37,719 Speaker 1: the energy flow is exactly the crucial concept here. Reactions 421 00:21:37,720 --> 00:21:41,280 Speaker 1: can either release energy when you form something or they 422 00:21:41,280 --> 00:21:44,680 Speaker 1: can cost energy. Right, So you can release energy when 423 00:21:44,680 --> 00:21:47,760 Speaker 1: you make something, which means that it takes energy to 424 00:21:47,880 --> 00:21:51,040 Speaker 1: break it up. Like if sticking things together releases energy, 425 00:21:51,200 --> 00:21:54,080 Speaker 1: then those things are now bound together and it costs 426 00:21:54,200 --> 00:21:57,040 Speaker 1: energy to break it up. If you like mechanical analogies, 427 00:21:57,080 --> 00:21:58,720 Speaker 1: you can think of this. They're like inside of a 428 00:21:58,760 --> 00:22:01,399 Speaker 1: cup together like up is now an analogy for like 429 00:22:01,440 --> 00:22:04,280 Speaker 1: the potential energy of this system, and when they fall 430 00:22:04,320 --> 00:22:06,600 Speaker 1: into the cup, they have to release energy to fall 431 00:22:06,680 --> 00:22:08,439 Speaker 1: into the cup. And then later if you want to 432 00:22:08,440 --> 00:22:11,040 Speaker 1: break it apart again, you have to put energy in. 433 00:22:11,280 --> 00:22:14,000 Speaker 1: So if you want to break helium into hydrogen, you 434 00:22:14,000 --> 00:22:16,080 Speaker 1: have to zap it with a laser to break it up. 435 00:22:16,160 --> 00:22:18,159 Speaker 1: So if it takes energy to break it up, that 436 00:22:18,240 --> 00:22:21,240 Speaker 1: means that it releases energy when you make it. Yeah, 437 00:22:21,440 --> 00:22:23,840 Speaker 1: I think it's still a little counterintuitive. I guess I'm 438 00:22:23,880 --> 00:22:26,159 Speaker 1: not quite wrapping my head around it or how to 439 00:22:26,200 --> 00:22:29,040 Speaker 1: explain it, because it feels like the atoms want to 440 00:22:29,040 --> 00:22:31,440 Speaker 1: be together to some degree, right, I mean, they stick 441 00:22:31,480 --> 00:22:33,640 Speaker 1: together because they attracted to each other, and so why 442 00:22:33,680 --> 00:22:37,119 Speaker 1: would that release energy if you are sticking them together. 443 00:22:37,280 --> 00:22:39,359 Speaker 1: In order for them to stick together, they have to 444 00:22:39,400 --> 00:22:41,800 Speaker 1: give up some of their energy. Sticking together means that 445 00:22:41,840 --> 00:22:44,800 Speaker 1: they're bound together. They're like together in a potential Well 446 00:22:44,960 --> 00:22:47,720 Speaker 1: think about an analogy in terms of like orbit, because 447 00:22:47,760 --> 00:22:50,960 Speaker 1: gravitational binding energy works the same way. If a planet 448 00:22:51,000 --> 00:22:53,080 Speaker 1: is flying by a sun and it has a huge 449 00:22:53,080 --> 00:22:55,080 Speaker 1: amount of energy, then the Sun is not going to 450 00:22:55,119 --> 00:22:57,199 Speaker 1: capture it. But if a planet is flying by the 451 00:22:57,200 --> 00:22:59,800 Speaker 1: Sun and it releases some of its energy, gives up 452 00:23:00,080 --> 00:23:02,320 Speaker 1: of its energy into something else, Like it bangs into 453 00:23:02,320 --> 00:23:04,919 Speaker 1: a rock and sends that rock away, it's lost some 454 00:23:05,000 --> 00:23:07,119 Speaker 1: of its energy, and then it can fall into the 455 00:23:07,119 --> 00:23:09,800 Speaker 1: gravitational well of the Sun and be trapped there. Now 456 00:23:09,840 --> 00:23:12,280 Speaker 1: you've given up some energy by banging into this rock 457 00:23:12,320 --> 00:23:15,440 Speaker 1: and sending it out to infinity and created this combined 458 00:23:15,520 --> 00:23:18,360 Speaker 1: state this planet that's now orbiting the Sun. So when 459 00:23:18,400 --> 00:23:22,040 Speaker 1: something falls into a potential well, it's losing energy, has 460 00:23:22,080 --> 00:23:24,600 Speaker 1: to give up that energy somehow. So in the same way, 461 00:23:24,720 --> 00:23:27,280 Speaker 1: two hydrogen atoms have like a lot of kinetic energy. 462 00:23:27,359 --> 00:23:29,639 Speaker 1: When they get trapped together into a helium, they have 463 00:23:29,720 --> 00:23:32,239 Speaker 1: to give up that energy to like release photons so 464 00:23:32,280 --> 00:23:35,640 Speaker 1: they can fall into the potential well of their binding state. 465 00:23:35,800 --> 00:23:38,280 Speaker 1: It might help to talk about where this energy comes from. 466 00:23:38,359 --> 00:23:41,359 Speaker 1: Like two hydrogen atoms before their fuse together, you're saying 467 00:23:41,359 --> 00:23:43,359 Speaker 1: they have a certain amount of energy and after you 468 00:23:43,400 --> 00:23:46,160 Speaker 1: fuse them, you're saying they have less energy together as 469 00:23:46,200 --> 00:23:48,360 Speaker 1: a pair. Where did this energy come from? You just said, 470 00:23:48,640 --> 00:23:51,120 Speaker 1: maybe the kinetic energy of these particles, or is it 471 00:23:51,160 --> 00:23:54,480 Speaker 1: in like the binding energy inside of their corks. So 472 00:23:54,520 --> 00:23:56,639 Speaker 1: it's not inside the binding energy of the corks that 473 00:23:56,720 --> 00:23:59,240 Speaker 1: the proton doesn't change. It comes from the energy of 474 00:23:59,280 --> 00:24:02,120 Speaker 1: the motion of hydrogen. These hydrogen atoms are a very 475 00:24:02,200 --> 00:24:04,120 Speaker 1: energetic state. They have to be in order to even 476 00:24:04,119 --> 00:24:06,320 Speaker 1: get close to each other because otherwise they're getting pushed 477 00:24:06,320 --> 00:24:10,000 Speaker 1: apart by the electrostatic repulsion. Because they're both positively charged, 478 00:24:10,080 --> 00:24:12,600 Speaker 1: so they have a lot of energy. You push them together, 479 00:24:12,800 --> 00:24:14,679 Speaker 1: and then in order to stay together in order like 480 00:24:14,720 --> 00:24:16,560 Speaker 1: fall into this hole together, they have to sort of 481 00:24:16,560 --> 00:24:19,199 Speaker 1: release energy. Think about, for example, if you're mini golfing 482 00:24:19,200 --> 00:24:21,280 Speaker 1: and you're trying to get a ball into a little 483 00:24:21,280 --> 00:24:23,399 Speaker 1: hole on the top of a volcano. You've got to 484 00:24:23,440 --> 00:24:25,679 Speaker 1: give it enough speeds so it gets up to the 485 00:24:25,680 --> 00:24:28,240 Speaker 1: top right and then it falls into the hole. Now 486 00:24:28,240 --> 00:24:30,040 Speaker 1: it's like stuck in that hole. It's got to give 487 00:24:30,119 --> 00:24:32,480 Speaker 1: up some energy to go into the hole. And so 488 00:24:32,520 --> 00:24:34,320 Speaker 1: in the same way, the hydrogen atom needs a lot 489 00:24:34,359 --> 00:24:36,760 Speaker 1: of speed to approach the other hydrogen atom. Then it 490 00:24:36,760 --> 00:24:39,359 Speaker 1: has to give up that speed when it falls into 491 00:24:39,359 --> 00:24:41,679 Speaker 1: the hole of the strong force which is attracting the 492 00:24:41,720 --> 00:24:44,439 Speaker 1: other one. Basically, you're saying they had some kinetic energy 493 00:24:44,560 --> 00:24:47,879 Speaker 1: when they were flying apart together, but once they smash 494 00:24:47,920 --> 00:24:50,280 Speaker 1: into each other, that energy, that kinetic energy has to 495 00:24:50,280 --> 00:24:53,040 Speaker 1: go somewhere, and that's basically the energy that powers the 496 00:24:53,080 --> 00:24:55,720 Speaker 1: sun is when these things smash into each other. Yeah, 497 00:24:55,720 --> 00:24:59,359 Speaker 1: the reorganization of two protons into helium has less energy 498 00:24:59,400 --> 00:25:02,199 Speaker 1: than just to two protons by themselves. Another way to 499 00:25:02,240 --> 00:25:05,040 Speaker 1: think about it is in terms of the mass. Remember 500 00:25:05,080 --> 00:25:08,000 Speaker 1: that mass is just a measure of how much energy 501 00:25:08,160 --> 00:25:11,440 Speaker 1: is stored inside something, not actually the amount of stuff, 502 00:25:11,600 --> 00:25:14,600 Speaker 1: and the mass of the helium atom is zero point 503 00:25:14,720 --> 00:25:18,400 Speaker 1: eight percent less than the mass of the nucleons that 504 00:25:18,480 --> 00:25:21,199 Speaker 1: make it up. But that's really just another way of 505 00:25:21,240 --> 00:25:24,840 Speaker 1: saying how much energy is stored in It has less 506 00:25:24,960 --> 00:25:28,600 Speaker 1: energy stored inside it than the nucleons that make it, right, 507 00:25:28,640 --> 00:25:30,399 Speaker 1: and so to get into that state you have to 508 00:25:30,440 --> 00:25:33,200 Speaker 1: release energy, just like how an electron when it moves 509 00:25:33,240 --> 00:25:35,679 Speaker 1: down an energy level around an atom, it has to 510 00:25:35,720 --> 00:25:38,359 Speaker 1: give up a photon to move down an energy level. Right, 511 00:25:38,480 --> 00:25:40,880 Speaker 1: energy is conserved there. In the same way here, these 512 00:25:40,920 --> 00:25:43,960 Speaker 1: two protons are moving into another state which has lower energy, 513 00:25:44,080 --> 00:25:46,080 Speaker 1: so they have to give up that energy. You might 514 00:25:46,119 --> 00:25:48,720 Speaker 1: ask like, well, why does it have lower energy? What's 515 00:25:48,760 --> 00:25:52,320 Speaker 1: lower energy? But having two protons stuck together than having 516 00:25:52,320 --> 00:25:55,359 Speaker 1: two protons fly apart, right, Yeah, I think that's the 517 00:25:55,400 --> 00:25:58,679 Speaker 1: main question. What's different. There's the mathematical answer, and then 518 00:25:58,720 --> 00:26:02,760 Speaker 1: there's the intuitive answer. Mathematically, whenever you have a force 519 00:26:02,880 --> 00:26:05,720 Speaker 1: that's attractive, you can think about it in terms of 520 00:26:05,760 --> 00:26:10,160 Speaker 1: a potential energy difference. Forces like to push things towards 521 00:26:10,280 --> 00:26:13,959 Speaker 1: lower potential energy the way gravity pulls a rock down 522 00:26:14,000 --> 00:26:18,760 Speaker 1: a hill to lower gravitational potential energy. So pulling something 523 00:26:18,920 --> 00:26:22,520 Speaker 1: in with an attractive force like the strong force means 524 00:26:22,680 --> 00:26:25,760 Speaker 1: bringing it to a lower energy state that's called the 525 00:26:25,800 --> 00:26:28,439 Speaker 1: binding energy. The way I think about it intuitively is 526 00:26:28,440 --> 00:26:31,240 Speaker 1: thinking about the reverse process, right, Like, if these two 527 00:26:31,280 --> 00:26:34,640 Speaker 1: things are stuck together, if the strong forces really holding 528 00:26:34,680 --> 00:26:36,840 Speaker 1: tightly on them, then you've got to zap them. You 529 00:26:36,880 --> 00:26:39,400 Speaker 1: have to give them energy to push them apart, right, 530 00:26:39,440 --> 00:26:41,359 Speaker 1: Just the same way if you want to release the 531 00:26:41,400 --> 00:26:43,280 Speaker 1: Earth from the Sun's orbit, you've got to give it 532 00:26:43,320 --> 00:26:45,600 Speaker 1: a push. If you want to break up the helium 533 00:26:45,680 --> 00:26:48,640 Speaker 1: nucleus into two hydrogen, You've gotta zap one of them 534 00:26:48,680 --> 00:26:51,040 Speaker 1: to release them from the pull of the other one, 535 00:26:51,160 --> 00:26:54,639 Speaker 1: and that cost energy. So if breaking it up cost energy, 536 00:26:54,760 --> 00:26:59,080 Speaker 1: then the reverse process forming it must release energy. All right, Well, 537 00:26:59,200 --> 00:27:02,680 Speaker 1: let's maybe move on and talk about what happens after that, 538 00:27:03,080 --> 00:27:05,919 Speaker 1: which is that you get heavier and heavier elements. But 539 00:27:05,960 --> 00:27:08,280 Speaker 1: this only works until you get to are So what 540 00:27:08,359 --> 00:27:10,479 Speaker 1: happens when you try to make iron? First of all, 541 00:27:10,480 --> 00:27:13,439 Speaker 1: how many steps are there between hydrogen and helium and 542 00:27:13,760 --> 00:27:16,119 Speaker 1: making iron? So you can keep going for a while. 543 00:27:16,440 --> 00:27:19,600 Speaker 1: You can combine helium together to make carbon, you can 544 00:27:19,640 --> 00:27:22,359 Speaker 1: combine carbon together with more helium to make oxygen. You 545 00:27:22,440 --> 00:27:25,560 Speaker 1: can keep going and make silicon and heavier and heavier stuff. 546 00:27:25,640 --> 00:27:28,840 Speaker 1: There's multiple steps there. It's not like one single pathway. 547 00:27:29,000 --> 00:27:31,160 Speaker 1: Now you can have lots of different combinations of things 548 00:27:31,160 --> 00:27:34,240 Speaker 1: that you can put together. And that happens inside the sun, 549 00:27:34,280 --> 00:27:37,080 Speaker 1: like you know, everything's mixing together with everything and making 550 00:27:37,119 --> 00:27:40,680 Speaker 1: different heavier elements. It happens inside some stars. In order 551 00:27:40,680 --> 00:27:42,560 Speaker 1: for those steps to happen, has to be hotter and hotter, 552 00:27:42,640 --> 00:27:46,240 Speaker 1: because now these nuclei have larger positive charges, so they're 553 00:27:46,240 --> 00:27:49,000 Speaker 1: pushing against each other even more so. In order to 554 00:27:49,000 --> 00:27:52,200 Speaker 1: get carbon diffuse together with other carbon or with something else, 555 00:27:52,280 --> 00:27:55,680 Speaker 1: it requires even more temperature and density. So our star 556 00:27:56,000 --> 00:27:59,440 Speaker 1: is not hot enough to fuse anything basically but hydrogen 557 00:27:59,560 --> 00:28:02,480 Speaker 1: into helium. But other stars out there in the universe are, 558 00:28:02,640 --> 00:28:04,800 Speaker 1: and they can keep fusing stuff all the way up 559 00:28:04,800 --> 00:28:09,920 Speaker 1: to iron. Our son cannot make heavier elements than helium. 560 00:28:09,960 --> 00:28:11,959 Speaker 1: Is that what you're saying, Like, our son is limited 561 00:28:11,960 --> 00:28:14,399 Speaker 1: to helium. Our son is limited to helium until the 562 00:28:14,520 --> 00:28:17,440 Speaker 1: very end of its life. For a few moments, near 563 00:28:17,480 --> 00:28:19,639 Speaker 1: the end of its life, maybe minutes or seconds, there 564 00:28:19,640 --> 00:28:22,000 Speaker 1: will be a little bit of helium burning. It's actually 565 00:28:22,040 --> 00:28:25,440 Speaker 1: called a helium flash because it all happens so quickly 566 00:28:25,560 --> 00:28:27,320 Speaker 1: near the end of its life, and it expands an 567 00:28:27,480 --> 00:28:30,879 Speaker 1: enormous amount of energy during these last moments. But for 568 00:28:31,040 --> 00:28:32,720 Speaker 1: most of the lifetime of the Sun, for the next 569 00:28:32,760 --> 00:28:35,440 Speaker 1: few billion years, it will not fuse any helium. It's 570 00:28:35,480 --> 00:28:38,120 Speaker 1: just not massive enough to create the temperature and pressure 571 00:28:38,120 --> 00:28:40,960 Speaker 1: at its core necessary to do that. Interesting. I feel 572 00:28:41,000 --> 00:28:43,560 Speaker 1: like that's something that testifysist don't talk about often, you know, 573 00:28:43,600 --> 00:28:45,760 Speaker 1: when they say we're made out of star stuff. Really, 574 00:28:45,800 --> 00:28:48,520 Speaker 1: they mean we were made out of some stars stuff. 575 00:28:48,640 --> 00:28:51,239 Speaker 1: Not all stars make stuff like us, Right, you need 576 00:28:51,280 --> 00:28:54,720 Speaker 1: special stars. Yeah, only the bigger, more massive stars are 577 00:28:54,760 --> 00:28:58,440 Speaker 1: capable of fusing heavier and heavier elements. Okay, but even 578 00:28:58,440 --> 00:29:01,560 Speaker 1: those big stars can combine carbon and hydrogen and make 579 00:29:01,560 --> 00:29:04,640 Speaker 1: these heavier elements. But even the biggest and hottest stars 580 00:29:04,760 --> 00:29:07,320 Speaker 1: have to stop at ore. And so the question is 581 00:29:07,360 --> 00:29:09,719 Speaker 1: why is that what's so special about? All Right? So, 582 00:29:09,760 --> 00:29:11,960 Speaker 1: as you move up the periodic table, you're getting more 583 00:29:11,960 --> 00:29:15,280 Speaker 1: protons and more neutrons in there. Things are getting tighter 584 00:29:15,320 --> 00:29:18,800 Speaker 1: and tighter. The binding energy actually increases because now you 585 00:29:18,840 --> 00:29:21,120 Speaker 1: have more of these things feeling the strong force and 586 00:29:21,200 --> 00:29:23,160 Speaker 1: pulling on each other. So as you go up the 587 00:29:23,160 --> 00:29:26,480 Speaker 1: periodic table, you're releasing more energy because the binding is 588 00:29:26,480 --> 00:29:30,480 Speaker 1: getting stronger. Remember, binding getting stronger means you need more 589 00:29:30,640 --> 00:29:32,800 Speaker 1: energy to break it up. So it takes a more 590 00:29:32,840 --> 00:29:35,080 Speaker 1: powerful laser to break up carbon than it does to 591 00:29:35,120 --> 00:29:37,960 Speaker 1: break up helium. Takes an even more powerful laser to 592 00:29:38,120 --> 00:29:41,160 Speaker 1: break up heavier elements than carbon, because as you keep 593 00:29:41,200 --> 00:29:44,000 Speaker 1: adding nucleons, they like to stick together even more. They're 594 00:29:44,000 --> 00:29:46,920 Speaker 1: like all working together to make this stuff even stickier, 595 00:29:47,120 --> 00:29:50,600 Speaker 1: And that's really the key that the binding energy per 596 00:29:51,000 --> 00:29:55,120 Speaker 1: nucleon is going up. As you do fusion all the 597 00:29:55,160 --> 00:29:58,200 Speaker 1: way up to iron, the potential well is getting deeper. 598 00:29:58,400 --> 00:30:02,200 Speaker 1: The atoms are getting stick year. You stick two atoms together, 599 00:30:02,640 --> 00:30:06,440 Speaker 1: but the combined atom has more than twice the original 600 00:30:06,520 --> 00:30:10,720 Speaker 1: binding energy, so it's more tightly bound per nucleon, which 601 00:30:10,760 --> 00:30:14,920 Speaker 1: is why it releases more energy to make that combined atom. 602 00:30:15,000 --> 00:30:17,560 Speaker 1: But wouldn't then release more energy? Is that kind of 603 00:30:17,640 --> 00:30:20,000 Speaker 1: like a runaway reaction in a way, Like you know, 604 00:30:20,120 --> 00:30:22,360 Speaker 1: Sun starts to make heavier elements and when you fuse 605 00:30:22,440 --> 00:30:25,160 Speaker 1: those together they release even more energy. It sounds like 606 00:30:25,160 --> 00:30:28,360 Speaker 1: what you're saying, Merging two carbons together releases a whole 607 00:30:28,400 --> 00:30:30,680 Speaker 1: bunch of energy, Yes, exactly. And so as you keep 608 00:30:30,720 --> 00:30:33,000 Speaker 1: going up to the periodic table, things get tighter and 609 00:30:33,040 --> 00:30:35,720 Speaker 1: tighter and you keep releasing energy. You can keep doing 610 00:30:35,720 --> 00:30:38,720 Speaker 1: fusion and it keeps releasing energy until you get to iron. 611 00:30:38,800 --> 00:30:41,720 Speaker 1: Iron is the tipping point when the electrostatic force takes 612 00:30:41,760 --> 00:30:44,240 Speaker 1: over again. And what happens is that the nucleus is 613 00:30:44,280 --> 00:30:47,600 Speaker 1: now so big that the strong force between protons on 614 00:30:47,680 --> 00:30:50,520 Speaker 1: like different sides of the nucleus can't really do its 615 00:30:50,520 --> 00:30:53,120 Speaker 1: thing anymore because the protons are so far apart. But 616 00:30:53,160 --> 00:30:56,800 Speaker 1: the electrostatic force, which is a longer range, much much 617 00:30:56,880 --> 00:30:59,440 Speaker 1: longer than the size of the nucleus, can so the 618 00:30:59,480 --> 00:31:02,160 Speaker 1: atom becomes a little bit less tightly bound. Instead of 619 00:31:02,160 --> 00:31:05,280 Speaker 1: adding another proton, which sticks everything together more, you're adding 620 00:31:05,280 --> 00:31:08,320 Speaker 1: another proton, which sticks everything together a little bit less. 621 00:31:08,600 --> 00:31:11,320 Speaker 1: So you're reducing the binding energy of the nucleus. You're 622 00:31:11,360 --> 00:31:14,960 Speaker 1: making it easier to break it up than it was before. Alternately, 623 00:31:15,040 --> 00:31:18,000 Speaker 1: you're saying it gets harder to fuse things to a 624 00:31:18,080 --> 00:31:20,840 Speaker 1: really big atom like art, Like, there are so many 625 00:31:20,920 --> 00:31:24,000 Speaker 1: protons inside of the nucleus of an iron atom that 626 00:31:24,160 --> 00:31:26,520 Speaker 1: is just super duper positive. There's a lot of positive 627 00:31:26,600 --> 00:31:28,960 Speaker 1: charge there in one spot, and so like, adding one 628 00:31:29,040 --> 00:31:31,920 Speaker 1: more proton just gets harder and harder a because there's 629 00:31:31,960 --> 00:31:35,440 Speaker 1: so much positivity they're repelling you. But also like even 630 00:31:35,680 --> 00:31:39,080 Speaker 1: the strongforce that's holding all those protons together gets kind 631 00:31:39,080 --> 00:31:41,760 Speaker 1: of more diluted. That's exactly right. But the thing that 632 00:31:41,800 --> 00:31:44,560 Speaker 1: controls whether or not this happens very often in stars 633 00:31:44,680 --> 00:31:46,920 Speaker 1: is really the energy flow, because what it means is 634 00:31:46,920 --> 00:31:50,440 Speaker 1: that to fuse iron together, for example, costs energy rather 635 00:31:50,480 --> 00:31:54,120 Speaker 1: than releasing energy, because fusing iron together I means sticking 636 00:31:54,120 --> 00:31:57,360 Speaker 1: it together into a bigger nucleus which is not as 637 00:31:57,480 --> 00:32:00,760 Speaker 1: tightly bound. Right, And so remember if something it's really 638 00:32:00,800 --> 00:32:03,680 Speaker 1: tightly bound, it costs more energy to break it up, 639 00:32:03,720 --> 00:32:06,440 Speaker 1: which means it releases energy to make it. If something 640 00:32:06,560 --> 00:32:09,479 Speaker 1: is less tightly bound, then it doesn't take as much 641 00:32:09,560 --> 00:32:12,080 Speaker 1: energy to break it up, so it costs energy to 642 00:32:12,240 --> 00:32:14,880 Speaker 1: make it. And so what happens after iron is now 643 00:32:14,960 --> 00:32:17,680 Speaker 1: you're making things that are less and less tightly bound, 644 00:32:17,800 --> 00:32:20,840 Speaker 1: and so it actually absorbs energy. It costs energy to 645 00:32:20,880 --> 00:32:23,000 Speaker 1: do it. You want to fuse iron together, you can 646 00:32:23,040 --> 00:32:25,760 Speaker 1: do it, but you take energy away from the star. 647 00:32:26,040 --> 00:32:28,240 Speaker 1: So in effect, you're like putting out the fire of 648 00:32:28,240 --> 00:32:30,880 Speaker 1: the star instead of fueling it for the next reaction, 649 00:32:31,000 --> 00:32:33,520 Speaker 1: you're cooling it down. Yeah, I feel like you're making 650 00:32:33,560 --> 00:32:37,200 Speaker 1: folks here do some superhero style mental gymnastics here. With 651 00:32:37,560 --> 00:32:41,240 Speaker 1: so many inversions, I think maybe it's simpiliary to put it. 652 00:32:41,280 --> 00:32:43,760 Speaker 1: Is that when you're fusing something simple like hydrogen, it 653 00:32:43,800 --> 00:32:45,800 Speaker 1: takes a little bit of energy to get the hydrogen's 654 00:32:45,800 --> 00:32:48,280 Speaker 1: atoms together, but once they fused, they release much more 655 00:32:48,360 --> 00:32:51,080 Speaker 1: energy than the energy took to get them together. But 656 00:32:51,120 --> 00:32:53,760 Speaker 1: as you get into these heavier and heavier and bigger atoms, 657 00:32:53,800 --> 00:32:56,560 Speaker 1: the energy it takes to like fuse something to them 658 00:32:56,960 --> 00:32:59,880 Speaker 1: is more than the energy that gets released when it 659 00:33:00,000 --> 00:33:04,200 Speaker 1: actually happens. Yeah, fusing iron together is an energy loser, right, 660 00:33:04,240 --> 00:33:07,520 Speaker 1: it costs energy to do that. The reason and we 661 00:33:07,560 --> 00:33:09,560 Speaker 1: say that a loot on the podcast, that you can't 662 00:33:09,640 --> 00:33:12,240 Speaker 1: make things heavy than iron because it cool stars. The 663 00:33:12,360 --> 00:33:16,040 Speaker 1: reason for the fundamental reason for why fusing iron together 664 00:33:16,280 --> 00:33:19,640 Speaker 1: cools star instead of heating a star the way fusing 665 00:33:19,720 --> 00:33:23,240 Speaker 1: hydrogen together does calm down to this nuclear binding energy. 666 00:33:23,280 --> 00:33:26,120 Speaker 1: How the nucleus is put together. When you put heavier 667 00:33:26,160 --> 00:33:29,400 Speaker 1: and heavier nuclei together, they are not as tightly bound. 668 00:33:29,400 --> 00:33:32,360 Speaker 1: They're easier to break up. So if you transition from 669 00:33:32,360 --> 00:33:36,400 Speaker 1: a nucleus which is more tightly bound to less tightly bound, 670 00:33:36,600 --> 00:33:38,480 Speaker 1: then it costs energy to do that. You have to 671 00:33:38,560 --> 00:33:41,600 Speaker 1: absorb energy to go from more tightly bound to less 672 00:33:41,600 --> 00:33:44,440 Speaker 1: tightly bound. You're like moving up energy levels, So it 673 00:33:44,560 --> 00:33:47,720 Speaker 1: costs energy. If you don't like thinking about the binding energy, 674 00:33:47,760 --> 00:33:51,040 Speaker 1: here's another way to think about it. Fission releases energy 675 00:33:51,200 --> 00:33:54,840 Speaker 1: because a heavy nucleus like uranium two thirty five is 676 00:33:54,880 --> 00:33:58,320 Speaker 1: like a cocked mouse trap. It took energy to squeeze 677 00:33:58,360 --> 00:34:01,680 Speaker 1: all those protons and neutral is hard enough together to 678 00:34:01,760 --> 00:34:05,440 Speaker 1: make them barely stick together using the nuclear force that 679 00:34:05,520 --> 00:34:08,520 Speaker 1: fights against the natural tendency of all those protons to 680 00:34:08,640 --> 00:34:12,799 Speaker 1: fly violently apart due to their electrostatic repulsion. So when 681 00:34:12,880 --> 00:34:16,240 Speaker 1: that heavy nucleus, the uranium two thirty five, is struck 682 00:34:16,280 --> 00:34:18,960 Speaker 1: by an incoming neutron, for example, it's like a mouse 683 00:34:19,120 --> 00:34:22,279 Speaker 1: touching the trigger pedal of the trap. Bang goes the 684 00:34:22,360 --> 00:34:25,200 Speaker 1: nucleus as it breaks apart. In the case of fusion, 685 00:34:25,400 --> 00:34:29,000 Speaker 1: the mechanism really is different. The nuclear force between the 686 00:34:29,160 --> 00:34:32,839 Speaker 1: nucleons is very powerfully attractive, but only kicks in when 687 00:34:32,880 --> 00:34:35,319 Speaker 1: the particles are so close to each other that they 688 00:34:35,320 --> 00:34:38,759 Speaker 1: are almost touching. That attraction is not quite enough to 689 00:34:38,840 --> 00:34:42,560 Speaker 1: stick the two protons together against their electrostatic repulsion. But 690 00:34:42,600 --> 00:34:44,879 Speaker 1: if you add two neutrons to the recipe, you get 691 00:34:45,040 --> 00:34:50,560 Speaker 1: enough mutually attractive nuclear force stickiness to overcome the electrostatics, 692 00:34:50,680 --> 00:34:54,000 Speaker 1: and the particles fall into each other's potential well like 693 00:34:54,040 --> 00:34:57,120 Speaker 1: a ball getting trapped in a cup, giving off energy 694 00:34:57,239 --> 00:35:00,680 Speaker 1: as they fall in, and that gives a powerful bang. Well, 695 00:35:00,719 --> 00:35:02,759 Speaker 1: maybe a question I might have is in the sun, 696 00:35:02,760 --> 00:35:05,000 Speaker 1: there's a lot going on, right Even in a big, 697 00:35:05,040 --> 00:35:07,879 Speaker 1: powerful sun that can make things like iron, there's still 698 00:35:08,000 --> 00:35:10,520 Speaker 1: hydrogen being fused and the lower elements being fused that 699 00:35:10,600 --> 00:35:13,480 Speaker 1: create a whole bunch of energy. You know, why can't 700 00:35:13,520 --> 00:35:18,000 Speaker 1: the Sun sustain an iron fusing reaction with the energy 701 00:35:18,120 --> 00:35:21,080 Speaker 1: from these other reactions? You know, like maybe making iron 702 00:35:21,120 --> 00:35:24,000 Speaker 1: cost energy, but it's also you know, getting a lot 703 00:35:24,040 --> 00:35:27,080 Speaker 1: of surplus energy from some of these other reactions it has, 704 00:35:27,239 --> 00:35:29,360 Speaker 1: And so why can't the Sun just keep making heavy 705 00:35:29,400 --> 00:35:32,480 Speaker 1: and heavier elements with its surplus energy. Yeah, that's a 706 00:35:32,480 --> 00:35:34,640 Speaker 1: good question. And remember that our sun can't even get 707 00:35:34,680 --> 00:35:37,560 Speaker 1: close to that situation because it can't even make iron, 708 00:35:37,640 --> 00:35:39,640 Speaker 1: so it's not really in the situation of trying to 709 00:35:39,719 --> 00:35:42,319 Speaker 1: fuse iron together with heavier stuff. But imagine some more 710 00:35:42,360 --> 00:35:45,440 Speaker 1: massive star that's hotter at its core and is capable 711 00:35:45,480 --> 00:35:47,279 Speaker 1: of fusing all the way up to iron, and you 712 00:35:47,320 --> 00:35:49,400 Speaker 1: can ask, like, why can't you make heavier stuff and 713 00:35:49,520 --> 00:35:51,759 Speaker 1: use up a little bit of that energy that you're 714 00:35:51,760 --> 00:35:54,640 Speaker 1: producing with all the other fusion processes you can? And 715 00:35:54,680 --> 00:35:56,759 Speaker 1: that does happen a little bit, but it tends to 716 00:35:56,840 --> 00:35:59,520 Speaker 1: kill the star, right, it tends to cool the star down, 717 00:35:59,760 --> 00:36:01,439 Speaker 1: and that's the end of the star. That's the death 718 00:36:01,480 --> 00:36:04,080 Speaker 1: of a star. Like if you put water onto a fire, 719 00:36:04,320 --> 00:36:06,640 Speaker 1: what happens, Well, you do heat the water up, certainly, 720 00:36:06,680 --> 00:36:08,719 Speaker 1: but it also cools the fire down, and so then 721 00:36:08,719 --> 00:36:10,520 Speaker 1: the fire goes out. So in the same way, once 722 00:36:10,520 --> 00:36:12,520 Speaker 1: you get to the point where you were cooling the star, 723 00:36:12,800 --> 00:36:14,799 Speaker 1: then the star is dying. So you do make a 724 00:36:14,840 --> 00:36:16,960 Speaker 1: little bit of stuff heavier than iron. It's not like 725 00:36:17,000 --> 00:36:19,600 Speaker 1: there's a total wall there, but you just can't make 726 00:36:19,719 --> 00:36:22,240 Speaker 1: very much of it. I think I still have questions 727 00:36:22,280 --> 00:36:24,279 Speaker 1: about that, And so let's talk about that and what 728 00:36:24,360 --> 00:36:27,120 Speaker 1: happens after you make iron, and why you can't even 729 00:36:27,239 --> 00:36:29,439 Speaker 1: use surplus energy to make it as far as let's 730 00:36:29,480 --> 00:36:42,160 Speaker 1: take another quick break. All right, we're having a stellar 731 00:36:42,320 --> 00:36:46,480 Speaker 1: conversation that's not ironic at all about how stars make iron. 732 00:36:46,880 --> 00:36:49,680 Speaker 1: And it seems like stars can fuse all of the 733 00:36:49,760 --> 00:36:54,160 Speaker 1: lighter elements, starting from hydrogen right up until carbon oxygen, 734 00:36:54,360 --> 00:36:56,080 Speaker 1: and but then it gets to iron and it can't 735 00:36:56,120 --> 00:36:59,920 Speaker 1: do it anymore sustainably. I think maybe that's the footnote 736 00:37:00,200 --> 00:37:02,000 Speaker 1: you would have to add here, is that stars can 737 00:37:02,120 --> 00:37:04,880 Speaker 1: make heavier elements and iron, it just can't make them 738 00:37:04,920 --> 00:37:10,319 Speaker 1: sustainably because it costs energy to make anything heavier than iron. Yeah, 739 00:37:10,440 --> 00:37:13,440 Speaker 1: the same way, like a fire can't make steam sustainably 740 00:37:13,480 --> 00:37:15,880 Speaker 1: if you just pour water onto the fire. What if 741 00:37:15,880 --> 00:37:19,360 Speaker 1: I just had a bigger fire, Like, can you imagine 742 00:37:19,680 --> 00:37:23,640 Speaker 1: a sun or a star that somehow can make heavier 743 00:37:23,680 --> 00:37:26,360 Speaker 1: elements and iron sustainably, Like it has so much hyngen 744 00:37:26,440 --> 00:37:29,120 Speaker 1: in it, perhaps that it can keep making heavier elements 745 00:37:29,160 --> 00:37:31,080 Speaker 1: for a while. I mean, I think that's basically what 746 00:37:31,239 --> 00:37:34,520 Speaker 1: happens inside stars. But it spells the end of a star. Right. 747 00:37:34,640 --> 00:37:36,560 Speaker 1: You have a huge corporation, for example, and you have 748 00:37:36,640 --> 00:37:39,320 Speaker 1: money losing divisions that are just growing bigger and bigger 749 00:37:39,320 --> 00:37:42,560 Speaker 1: and bigger and sapping the profits from the money making divisions, 750 00:37:42,600 --> 00:37:44,480 Speaker 1: then your business is not going to last very long 751 00:37:44,520 --> 00:37:47,080 Speaker 1: before you go bankrupt. So these stars basically start to 752 00:37:47,080 --> 00:37:49,960 Speaker 1: go bankrupt as soon as they turn over past iron 753 00:37:50,040 --> 00:37:52,359 Speaker 1: and nickel because they start to use up their own 754 00:37:52,400 --> 00:37:55,400 Speaker 1: heat instead of producing more heat. So maybe the answer 755 00:37:55,440 --> 00:37:58,680 Speaker 1: here is that stars can fuse iron. Right, I feel 756 00:37:58,680 --> 00:38:03,080 Speaker 1: like maybe we like or Innerstanuel. Because stars can make iron, 757 00:38:03,080 --> 00:38:05,640 Speaker 1: it can probably go all the way up to heavier 758 00:38:05,680 --> 00:38:08,719 Speaker 1: and every amassie. It just can't do it sustainably, right, 759 00:38:09,480 --> 00:38:12,480 Speaker 1: But it can, and they do make heavier elements in iron. 760 00:38:12,640 --> 00:38:14,920 Speaker 1: But you're saying, it's kind of marks the point in 761 00:38:15,000 --> 00:38:18,080 Speaker 1: the Sun's balance sheet where it starts to lose energy. 762 00:38:18,200 --> 00:38:20,359 Speaker 1: But then, how much longer after that does the star 763 00:38:20,480 --> 00:38:24,040 Speaker 1: have before it dies or collapses? Not very long. One 764 00:38:24,040 --> 00:38:26,560 Speaker 1: of the really cool things about stellar evolution is how 765 00:38:26,600 --> 00:38:29,200 Speaker 1: the first stages can take a very very long time 766 00:38:29,280 --> 00:38:32,560 Speaker 1: hydrogen burning, and the next stages become much faster. So 767 00:38:32,600 --> 00:38:35,640 Speaker 1: you can burn hydrogen for millions or billions of years 768 00:38:35,719 --> 00:38:38,880 Speaker 1: and then burn helium for like days or minutes, and 769 00:38:39,000 --> 00:38:42,239 Speaker 1: every step after that gets faster and faster. The wise 770 00:38:42,320 --> 00:38:44,640 Speaker 1: that because what happens is that the temperature is increasing, 771 00:38:44,719 --> 00:38:48,160 Speaker 1: and as the temperature increases, fusion happens faster, which then 772 00:38:48,200 --> 00:38:51,160 Speaker 1: increases the temperature, which makes fusion happen faster. So it's 773 00:38:51,200 --> 00:38:53,360 Speaker 1: a runaway effect. But then when you get to iron, 774 00:38:53,400 --> 00:38:56,040 Speaker 1: when that help cool it down and stabilize it. When 775 00:38:56,080 --> 00:38:58,200 Speaker 1: you get to iron, that does help cool it down. 776 00:38:58,320 --> 00:39:00,399 Speaker 1: But now you have a heart of a star which 777 00:39:00,440 --> 00:39:02,799 Speaker 1: doesn't have what it needs in order to fuse. Right, 778 00:39:03,040 --> 00:39:06,479 Speaker 1: this cold blob of iron at the heart of your star. 779 00:39:06,680 --> 00:39:09,920 Speaker 1: You know, these shells of lighter materials going all the 780 00:39:09,960 --> 00:39:12,200 Speaker 1: way out, like the hydrogen has been pushed all the 781 00:39:12,239 --> 00:39:14,440 Speaker 1: way out to the outside of the star, and there 782 00:39:14,520 --> 00:39:16,960 Speaker 1: was only hydrogen burning happening on the edges. And they 783 00:39:16,960 --> 00:39:18,920 Speaker 1: have a layer of helium which is burning, and then 784 00:39:18,960 --> 00:39:20,719 Speaker 1: you have a layer of carbon which is burning, and 785 00:39:20,840 --> 00:39:23,399 Speaker 1: layers of oxygen and neon, et cetera all the way 786 00:39:23,400 --> 00:39:25,359 Speaker 1: down to iron at the heart. So now the core 787 00:39:25,400 --> 00:39:27,560 Speaker 1: of the star starts to cool down, and that's what 788 00:39:27,600 --> 00:39:30,960 Speaker 1: triggers this collapse. By the way, iron Heart is the 789 00:39:31,040 --> 00:39:34,239 Speaker 1: name of a superhero as well. Tony starts protege who 790 00:39:34,239 --> 00:39:36,840 Speaker 1: built her own iron suit. So then then that's where 791 00:39:36,960 --> 00:39:41,480 Speaker 1: stars basically collapse and becomes super nervous. Right for some stars, 792 00:39:41,520 --> 00:39:43,920 Speaker 1: I should say, the reason that stars aren't collapsing in 793 00:39:43,960 --> 00:39:47,360 Speaker 1: the first place is this heat produced from fusion. Fusion 794 00:39:47,440 --> 00:39:50,439 Speaker 1: is what's pushing back against gravity to keep a star 795 00:39:50,520 --> 00:39:52,880 Speaker 1: in balance. That's why it keeps going for billions of 796 00:39:53,000 --> 00:39:55,040 Speaker 1: years the way that it can. And so once the 797 00:39:55,040 --> 00:39:57,560 Speaker 1: star starts to cool and fusion starts to slow down, 798 00:39:57,760 --> 00:39:59,440 Speaker 1: then that spells the end of it, and it starts 799 00:39:59,440 --> 00:40:01,880 Speaker 1: to collapse, and then you can get a supernova. In 800 00:40:01,920 --> 00:40:04,600 Speaker 1: some cases, you can just get a gravitational collapse, which 801 00:40:04,680 --> 00:40:07,319 Speaker 1: leads to like a white dwarf or a neutron star 802 00:40:07,600 --> 00:40:10,480 Speaker 1: or a black hole. All sorts of fun outcomes, right, 803 00:40:10,480 --> 00:40:12,560 Speaker 1: because what happens is that the star makes heavier and 804 00:40:12,600 --> 00:40:15,440 Speaker 1: heavier elements. It gets up to iron iron causes it 805 00:40:15,480 --> 00:40:17,960 Speaker 1: to cool down. Then you've got all this cold iron 806 00:40:17,960 --> 00:40:20,160 Speaker 1: in the middle of the star. And then basically that's 807 00:40:20,200 --> 00:40:22,800 Speaker 1: when gravity kind of wins, right, takes all that iron 808 00:40:22,840 --> 00:40:26,319 Speaker 1: and squishes it down to like super duper dense materials 809 00:40:26,400 --> 00:40:29,200 Speaker 1: and which can either stay there or cost the whole 810 00:40:29,320 --> 00:40:32,520 Speaker 1: star to collapse and explode. Yeah, I think gravity only 811 00:40:32,560 --> 00:40:34,919 Speaker 1: really wins if you get to a black hole. Even 812 00:40:34,920 --> 00:40:37,399 Speaker 1: if you get to something really dense like a neutron star, 813 00:40:37,600 --> 00:40:40,879 Speaker 1: gravity is still being resisted. There's still some force there 814 00:40:40,920 --> 00:40:44,239 Speaker 1: that's pushing back to prevent the collapse into a black hole. 815 00:40:44,400 --> 00:40:46,520 Speaker 1: And so like a white dwarf, for example, is just 816 00:40:46,560 --> 00:40:48,920 Speaker 1: like a big hot lump of that metal that was 817 00:40:48,960 --> 00:40:52,120 Speaker 1: made inside the star and it's resisting gravity trying to 818 00:40:52,120 --> 00:40:54,520 Speaker 1: compress it into a black hole. But Yeah, there are 819 00:40:54,600 --> 00:40:58,080 Speaker 1: various stages of retreats sort of against gravity. As gravity 820 00:40:58,080 --> 00:41:01,359 Speaker 1: gets stronger and stronger, collapses a huge burning star into 821 00:41:01,360 --> 00:41:04,720 Speaker 1: a white dwarf, into a neutron star, or maybe even 822 00:41:04,760 --> 00:41:08,200 Speaker 1: into a black hole. Yeah, but some stars collapse, and 823 00:41:08,239 --> 00:41:12,359 Speaker 1: that collapsation causes kind of like a rebound, right, because 824 00:41:12,400 --> 00:41:15,120 Speaker 1: there's all the star basic collapses in on itself with 825 00:41:15,320 --> 00:41:18,520 Speaker 1: like rebounds, and that's one of the kinds of supernova 826 00:41:18,680 --> 00:41:22,080 Speaker 1: that exists out there, right, That's what causes some supernova. Yeah. 827 00:41:22,080 --> 00:41:24,359 Speaker 1: If you have a massive enough star to start from 828 00:41:24,400 --> 00:41:27,080 Speaker 1: something like eight times the mass of our Sun, then 829 00:41:27,120 --> 00:41:29,399 Speaker 1: this last stages, it puffs out to be a red 830 00:41:29,400 --> 00:41:32,200 Speaker 1: supergiant and then it collapses until we call it type 831 00:41:32,200 --> 00:41:35,200 Speaker 1: two supernova. It's a gravitational collapse, and then you can 832 00:41:35,239 --> 00:41:37,520 Speaker 1: get like a black hole or a neutron star at 833 00:41:37,560 --> 00:41:39,880 Speaker 1: its heart. If you have a lower mass star, like 834 00:41:40,080 --> 00:41:42,080 Speaker 1: less than eight times the mass of the Sun, then 835 00:41:42,080 --> 00:41:44,680 Speaker 1: you're more likely to get like a white dwarf as 836 00:41:44,680 --> 00:41:47,400 Speaker 1: an outcome. And if that white dwarf then later gets 837 00:41:47,400 --> 00:41:50,239 Speaker 1: some more mass added to it, then it can collapse 838 00:41:50,400 --> 00:41:53,759 Speaker 1: into a type one a supernova. Right, But then I think, 839 00:41:53,800 --> 00:41:56,640 Speaker 1: what's interesting is that in these events, like when a 840 00:41:56,719 --> 00:42:00,920 Speaker 1: star goes supernova, that's then when the heavier elements get made, right, 841 00:42:01,040 --> 00:42:03,600 Speaker 1: That's when there's so much energy being released that the 842 00:42:03,680 --> 00:42:07,279 Speaker 1: shock wave compresses things and there's enough energy there to 843 00:42:07,320 --> 00:42:10,160 Speaker 1: actually fuse these heavier elements. Yes, so, as we said earlier, 844 00:42:10,200 --> 00:42:12,680 Speaker 1: there's a little bit of fusion of these heavier elements, 845 00:42:12,719 --> 00:42:15,440 Speaker 1: things heavier than iron inside the star that tends to 846 00:42:15,520 --> 00:42:18,520 Speaker 1: cool the star. But most of the heavy elements in 847 00:42:18,560 --> 00:42:21,280 Speaker 1: the universe, the gold and the platinum and the uranium, 848 00:42:21,280 --> 00:42:24,080 Speaker 1: are not made inside those stars. They're made either at 849 00:42:24,080 --> 00:42:26,600 Speaker 1: the end of the star, like during the supernova, when 850 00:42:26,600 --> 00:42:29,520 Speaker 1: so much energy is released that you can use some 851 00:42:29,600 --> 00:42:32,239 Speaker 1: of it up to fuse these even heavier things, and 852 00:42:32,360 --> 00:42:36,120 Speaker 1: also much later on when neutron stars, which are the 853 00:42:36,160 --> 00:42:39,319 Speaker 1: remnants of some of these supernovas, when those collide, and 854 00:42:39,360 --> 00:42:43,080 Speaker 1: then you can get enormous creation, like entire earth sized 855 00:42:43,160 --> 00:42:45,920 Speaker 1: chunks of gold or platinum can be made in those 856 00:42:46,080 --> 00:42:49,520 Speaker 1: neutron star collisions. Right. So, in a way, stars doop 857 00:42:49,640 --> 00:42:52,359 Speaker 1: use iron and make heavier elements, right, I mean, they 858 00:42:52,360 --> 00:42:54,040 Speaker 1: don't just make it at the end of their lives. 859 00:42:54,040 --> 00:42:57,319 Speaker 1: But also in these new ways they do make the 860 00:42:57,320 --> 00:42:59,719 Speaker 1: heavier elements, that's true. I guess they can get some 861 00:43:00,239 --> 00:43:03,120 Speaker 1: for that as well. I mean they get all the credit, right, Like, 862 00:43:03,160 --> 00:43:05,720 Speaker 1: are these heavier elements made any other way. It's almost 863 00:43:05,920 --> 00:43:09,759 Speaker 1: entirely supernova and neutron star mergers. And I guess you 864 00:43:09,760 --> 00:43:12,479 Speaker 1: could say the neutron star comes from the original star, 865 00:43:12,560 --> 00:43:14,520 Speaker 1: and so when you merge it together to make gold 866 00:43:14,600 --> 00:43:17,680 Speaker 1: or platinum or plutonium or whatever, that gets credited on 867 00:43:17,719 --> 00:43:20,359 Speaker 1: the account of the original star. It's a different sort 868 00:43:20,360 --> 00:43:22,680 Speaker 1: of process though, right. It's not fusion happening at the 869 00:43:22,680 --> 00:43:25,400 Speaker 1: heart of the star the way you make carbon and silicon, 870 00:43:25,520 --> 00:43:27,759 Speaker 1: though it is a product of the star which is 871 00:43:27,840 --> 00:43:31,200 Speaker 1: later fusing together to make these heavy elements. Not the 872 00:43:31,239 --> 00:43:34,279 Speaker 1: same process, but still fusing the elements together to make 873 00:43:34,320 --> 00:43:37,120 Speaker 1: heavier elements. Yeah, it certainly is fusion, and it costs 874 00:43:37,239 --> 00:43:40,239 Speaker 1: energy in that case, right, instead of creating energy. And 875 00:43:40,280 --> 00:43:43,600 Speaker 1: that's kind of why these heavier elements are also so rarer, right, 876 00:43:43,680 --> 00:43:46,040 Speaker 1: because they're only made at the end of the life 877 00:43:46,080 --> 00:43:48,759 Speaker 1: of a star and only briefly. And so that's why, 878 00:43:49,000 --> 00:43:51,080 Speaker 1: for example, here on Earth, there's a ton of iron, 879 00:43:51,480 --> 00:43:54,399 Speaker 1: but not a lot of gold or titanium. Yeah, that's 880 00:43:54,400 --> 00:43:56,920 Speaker 1: why the core of the Earth is mostly iron and 881 00:43:57,080 --> 00:43:59,799 Speaker 1: nickel and these kinds of things, and not gold and 882 00:44:00,280 --> 00:44:03,600 Speaker 1: platinum and not uranium. That's why these really heavy elements 883 00:44:03,640 --> 00:44:06,680 Speaker 1: are traced in the universe, compared to iron and nickel, 884 00:44:06,719 --> 00:44:10,520 Speaker 1: which are like the endpoints of stellar nucleosynthesis. Stars are 885 00:44:10,560 --> 00:44:14,359 Speaker 1: like factories for turning hydrogen into heavier stuff, but they 886 00:44:14,400 --> 00:44:16,959 Speaker 1: can only do that sustainably up to about iron, which 887 00:44:17,000 --> 00:44:20,040 Speaker 1: really controls what life on Earth is made out of, 888 00:44:20,080 --> 00:44:23,480 Speaker 1: what Earth itself is made out of. Yeah, including us 889 00:44:23,600 --> 00:44:26,200 Speaker 1: and Danny. Are you saying that gold and titanium are 890 00:44:26,200 --> 00:44:28,120 Speaker 1: basically made out of iron as well, because you have 891 00:44:28,160 --> 00:44:30,440 Speaker 1: to merge iron to make gold and titanium. Yeah, I 892 00:44:30,480 --> 00:44:32,839 Speaker 1: suppose so. In that same sense, everything is made out 893 00:44:32,840 --> 00:44:35,280 Speaker 1: of hydrogen, right, You and I were both just hydrogen. 894 00:44:35,440 --> 00:44:38,399 Speaker 1: I'm just saying iron Man is named appropriately because even 895 00:44:38,440 --> 00:44:41,160 Speaker 1: if it's made out of golden titanium, it does have ironum. 896 00:44:41,200 --> 00:44:44,080 Speaker 1: Although technically you're saying you should be maybe called hydrogen man, 897 00:44:44,280 --> 00:44:47,680 Speaker 1: should hyrogen man exactly. Something that's really interesting for me 898 00:44:47,719 --> 00:44:50,120 Speaker 1: to think about, sort of philosophically, is to think about 899 00:44:50,160 --> 00:44:54,360 Speaker 1: the difference between for example, oxygen and helium right in 900 00:44:54,400 --> 00:44:57,080 Speaker 1: the end, they're really the same components. Like a single 901 00:44:57,160 --> 00:45:00,680 Speaker 1: atom of oxygen has twenty four up corks, twenty four 902 00:45:00,719 --> 00:45:04,000 Speaker 1: down corks, and eight electrons. If you take four atoms 903 00:45:04,000 --> 00:45:06,719 Speaker 1: of helium, it has the same thing. It's twenty four ups, 904 00:45:06,760 --> 00:45:10,680 Speaker 1: twenty four downs, and eight electrons. It's just arranged differently. 905 00:45:10,880 --> 00:45:13,360 Speaker 1: And so all we're doing in the hearts of stars 906 00:45:13,400 --> 00:45:16,480 Speaker 1: and in supernova and in neutron star collisions is just 907 00:45:16,600 --> 00:45:19,839 Speaker 1: moving the pieces around to make different arrangements. And that's 908 00:45:19,880 --> 00:45:23,240 Speaker 1: what makes oxygen different from helium, and different from iron, 909 00:45:23,280 --> 00:45:26,040 Speaker 1: and different from titanium. And so it's fascinating to me 910 00:45:26,120 --> 00:45:28,400 Speaker 1: to see this happened. That the crucial thing is the 911 00:45:28,480 --> 00:45:31,439 Speaker 1: arrangement of those bits and the energy needed to put 912 00:45:31,440 --> 00:45:34,400 Speaker 1: the bits together into these special arrangements to make up 913 00:45:34,480 --> 00:45:37,719 Speaker 1: me and you and Iron Man. Yeah, it's fascinating. So 914 00:45:37,800 --> 00:45:39,480 Speaker 1: you're saying, instead of saying we're all made out of 915 00:45:39,520 --> 00:45:41,799 Speaker 1: star stuff, we should be saying we're all made out 916 00:45:41,840 --> 00:45:46,280 Speaker 1: of quirks, and all superheroes should just be called Corkman exactly, 917 00:45:46,560 --> 00:45:50,920 Speaker 1: or also Corkman, Captain America, Captain cork Hey. I'm a reductionist, right, 918 00:45:50,960 --> 00:45:53,400 Speaker 1: I'd like to reduce everything to the simplest possible terms. 919 00:45:53,640 --> 00:45:56,680 Speaker 1: There you go, just call everything cork. All right. Well, 920 00:45:56,680 --> 00:46:00,160 Speaker 1: it's interesting to think about the processes that lead to 921 00:46:00,280 --> 00:46:02,360 Speaker 1: all of the things that we see around us and 922 00:46:02,520 --> 00:46:05,120 Speaker 1: the inside of our phones, inside of our bodies, and 923 00:46:05,239 --> 00:46:08,040 Speaker 1: kind of reflect on why we're here. We're here because 924 00:46:08,239 --> 00:46:12,400 Speaker 1: of these processes that happen inside of previous generations of stars, 925 00:46:12,480 --> 00:46:15,280 Speaker 1: and how the physics of the universe limits that and 926 00:46:15,560 --> 00:46:18,279 Speaker 1: kind of determines the things that we are made out of, 927 00:46:18,400 --> 00:46:21,040 Speaker 1: and how those bits are arranged together. And even though 928 00:46:21,040 --> 00:46:24,120 Speaker 1: the universe has been working for billions of years to 929 00:46:24,440 --> 00:46:27,719 Speaker 1: convert hydrogen into more interesting stuff, it's still got a 930 00:46:27,800 --> 00:46:31,600 Speaker 1: long way ago. Universe is about nine two percent hydrogen 931 00:46:31,760 --> 00:46:34,759 Speaker 1: still after billions of years, and most of the rest 932 00:46:34,760 --> 00:46:37,080 Speaker 1: of that is just helium. The bits that make up 933 00:46:37,160 --> 00:46:39,680 Speaker 1: me and you and everything else, The interesting bits, the 934 00:46:39,719 --> 00:46:42,920 Speaker 1: heavy bits, are a tiny fraction of one percent of 935 00:46:42,960 --> 00:46:45,919 Speaker 1: the universe. Yeah, so even when the Avengers assembled, they're 936 00:46:45,920 --> 00:46:48,960 Speaker 1: still made out of court. Alright, Well, we hope you 937 00:46:49,040 --> 00:46:52,000 Speaker 1: enjoyed that. Thanks for joining us, See you next time. 938 00:46:59,719 --> 00:47:02,520 Speaker 1: Thanks you're listening, and remember that Daniel and Jorge Explain 939 00:47:02,560 --> 00:47:05,400 Speaker 1: the Universe is a production of I heart Radio. For 940 00:47:05,600 --> 00:47:08,520 Speaker 1: more podcast from my heart Radio, visit the i heart 941 00:47:08,600 --> 00:47:12,200 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 942 00:47:12,239 --> 00:47:14,920 Speaker 1: favorite shows. H