1 00:00:08,600 --> 00:00:11,640 Speaker 1: Hey, Daniel, do you like looking for shooting stars? I 2 00:00:11,760 --> 00:00:15,080 Speaker 1: do because sometimes the nice sky is really static, it 3 00:00:15,080 --> 00:00:18,680 Speaker 1: seems frozen, and so it's exciting to see something streak 4 00:00:18,800 --> 00:00:21,120 Speaker 1: and flame out across the sky. You know they aren't 5 00:00:21,160 --> 00:00:25,160 Speaker 1: really stars, right, Um? I am aware, thank you very much. 6 00:00:25,400 --> 00:00:29,360 Speaker 1: I also know that nobody's actually shooting those stars as 7 00:00:29,400 --> 00:00:33,519 Speaker 1: far as we know. You know aliens. Hello, you're going 8 00:00:33,560 --> 00:00:37,000 Speaker 1: to hit the aliens button before me. But it would 9 00:00:37,000 --> 00:00:40,280 Speaker 1: be cool to actually see a star explode, you know 10 00:00:40,280 --> 00:00:42,120 Speaker 1: what I mean. You're looking at at the sky and 11 00:00:42,159 --> 00:00:45,000 Speaker 1: suddenly one of them just goes Yeah, as long as 12 00:00:45,040 --> 00:00:47,560 Speaker 1: it's not our star, would be pretty fun to watch. 13 00:01:04,120 --> 00:01:08,040 Speaker 1: Hi am poor handmade cartoonists and the creator of PhD comics. Hi. 14 00:01:08,240 --> 00:01:11,360 Speaker 1: I'm Daniel Whitson. I'm a particle physicist, and I'm the 15 00:01:11,440 --> 00:01:14,480 Speaker 1: co author of the book We Have No Idea, A 16 00:01:14,520 --> 00:01:17,640 Speaker 1: Guide to the Unknown Universe, book about all the things 17 00:01:17,680 --> 00:01:20,360 Speaker 1: we don't know about the universe. And you wrote it 18 00:01:20,400 --> 00:01:23,720 Speaker 1: with a really awesome and fun cartoonist, didn't you? I did, 19 00:01:23,760 --> 00:01:27,000 Speaker 1: in fact, and I was recently contacted by one of 20 00:01:27,040 --> 00:01:30,200 Speaker 1: our listeners and one of our readers in the Czech Republic, 21 00:01:30,280 --> 00:01:33,240 Speaker 1: who's reading our book in check, I hope it says 22 00:01:33,240 --> 00:01:35,680 Speaker 1: the same things. It doesn't English. Well, he actually told 23 00:01:35,720 --> 00:01:39,880 Speaker 1: me how to translate the title in check literally into English. 24 00:01:40,040 --> 00:01:42,920 Speaker 1: But how does it translate. Apparently it translates to we 25 00:01:43,040 --> 00:01:47,640 Speaker 1: don't even know fart about it. Really, the word fart, 26 00:01:47,720 --> 00:01:50,560 Speaker 1: isn't it? He says. It's a very common expression in 27 00:01:50,640 --> 00:01:53,480 Speaker 1: check for I don't know fart about that, and that's 28 00:01:53,520 --> 00:01:56,240 Speaker 1: the expression they chose for the title in check. Wow. 29 00:01:56,280 --> 00:01:58,040 Speaker 1: I wonder if we had named that, made that the 30 00:01:58,120 --> 00:02:00,840 Speaker 1: actual title in English, maybe we would assault, we would 31 00:02:00,840 --> 00:02:03,560 Speaker 1: dislike more copies. I don't know. Maybe the book would 32 00:02:03,600 --> 00:02:05,760 Speaker 1: kind of stink. But it's a really fun book. It's 33 00:02:05,800 --> 00:02:09,160 Speaker 1: all about the unanswered questions of the universe, all the 34 00:02:09,200 --> 00:02:12,160 Speaker 1: things we'd like to know about our lives and where 35 00:02:12,240 --> 00:02:14,360 Speaker 1: and where we live and how the universe began but 36 00:02:14,560 --> 00:02:17,560 Speaker 1: don't yet know. And so we hope on this podcast 37 00:02:17,639 --> 00:02:19,240 Speaker 1: to take you on a tour of what we do 38 00:02:19,280 --> 00:02:21,640 Speaker 1: and don't know about the universe, and maybe one of 39 00:02:21,680 --> 00:02:23,600 Speaker 1: you out there, a young budding scientist, will be the 40 00:02:23,600 --> 00:02:26,200 Speaker 1: one to figure out the answers. That's right. We bring 41 00:02:26,240 --> 00:02:28,280 Speaker 1: to you all the amazing mysteries of the universe, and 42 00:02:28,320 --> 00:02:31,639 Speaker 1: all the farts in the universe and all the mysterious 43 00:02:31,680 --> 00:02:35,120 Speaker 1: farts in the US parts, the ones that fortunately you 44 00:02:35,200 --> 00:02:38,400 Speaker 1: can't smell through this audio podcast. Well, welcome to Daniel 45 00:02:38,440 --> 00:02:41,200 Speaker 1: and Jorge Explain the Universe, a production of I Heart 46 00:02:41,280 --> 00:02:44,160 Speaker 1: Radio in which we examine them the amazing, the mysterious, 47 00:02:44,280 --> 00:02:46,959 Speaker 1: all the weird and wonderful things in our bonkers universe, 48 00:02:47,080 --> 00:02:48,639 Speaker 1: and we talk about them in a way we hope 49 00:02:48,760 --> 00:02:51,560 Speaker 1: entertains you and also teaches you something deep about the 50 00:02:51,600 --> 00:02:54,600 Speaker 1: physics of our universe. Yeah, we talked about all the 51 00:02:55,240 --> 00:02:58,680 Speaker 1: sort of a nice and beautiful and wonderful, inspiring things 52 00:02:58,760 --> 00:03:01,080 Speaker 1: that are out there in universe, the big and the small, 53 00:03:01,120 --> 00:03:03,400 Speaker 1: but we also talk about some of the crazy things 54 00:03:03,400 --> 00:03:06,520 Speaker 1: that happened. That's right, because the universe is dramatic and 55 00:03:06,560 --> 00:03:09,440 Speaker 1: it is violent, and when it wants to make a splash, 56 00:03:09,520 --> 00:03:16,840 Speaker 1: it goes big, it goes supernova, it goes hyper nova, hypernova. Yeah, 57 00:03:16,919 --> 00:03:19,720 Speaker 1: So to be on the program, we'll be tackling perhaps 58 00:03:19,760 --> 00:03:22,960 Speaker 1: one of the most um I don't know, violent or 59 00:03:23,440 --> 00:03:27,520 Speaker 1: you know, dramatic or you know, maybe interesting events that 60 00:03:27,600 --> 00:03:30,040 Speaker 1: happened out in the universe. And that happens quite a bit. 61 00:03:30,320 --> 00:03:32,600 Speaker 1: That's right. It's one of the most interesting and dramatic 62 00:03:32,639 --> 00:03:34,960 Speaker 1: things that can happen in our universe. One of the 63 00:03:34,960 --> 00:03:37,080 Speaker 1: things we've seen, the kind of thing that we can 64 00:03:37,120 --> 00:03:40,800 Speaker 1: even find in historical records that people in ancient times 65 00:03:40,960 --> 00:03:43,720 Speaker 1: noticed happening in the sky and wondered what it was 66 00:03:43,720 --> 00:03:46,120 Speaker 1: all about? Right, and then so the question is how 67 00:03:46,200 --> 00:03:48,040 Speaker 1: much do we know about it? How much do we 68 00:03:48,680 --> 00:03:52,480 Speaker 1: understand about this incredible event and what we can do 69 00:03:52,760 --> 00:03:55,360 Speaker 1: if one happens near us? Yeah, and the answer is 70 00:03:55,400 --> 00:04:00,520 Speaker 1: basically dig a hole and pray. All right, let's get 71 00:04:00,560 --> 00:04:02,360 Speaker 1: into that. So to be on the podcast will be 72 00:04:02,400 --> 00:04:12,120 Speaker 1: asking the question what makes a supernova blow explode? I 73 00:04:12,160 --> 00:04:15,520 Speaker 1: guess super what makes a supernova explode? Or what makes 74 00:04:15,520 --> 00:04:21,320 Speaker 1: a supernova a supernova? What makes a supernova so super? Yeah? Yeah, 75 00:04:21,520 --> 00:04:24,840 Speaker 1: why isn't it a super dupernova? Or well, you know, 76 00:04:24,960 --> 00:04:28,040 Speaker 1: the name nova is actually quite fascinating. It means new 77 00:04:28,560 --> 00:04:32,039 Speaker 1: and so super. So supernova is like something super and 78 00:04:32,200 --> 00:04:34,720 Speaker 1: new in the sky. It comes from people looking at 79 00:04:34,760 --> 00:04:37,320 Speaker 1: the sky and saying, hey, that wasn't there before, or 80 00:04:37,400 --> 00:04:40,720 Speaker 1: that's different, and it's pretty rare to see something change 81 00:04:40,760 --> 00:04:42,880 Speaker 1: in the sky. I mean, we're used to the patterns 82 00:04:42,880 --> 00:04:44,760 Speaker 1: of the seasons and the days and the nights and 83 00:04:44,800 --> 00:04:48,080 Speaker 1: all that stuff. But otherwise the stars, you know, their 84 00:04:48,120 --> 00:04:51,160 Speaker 1: lifespan is much longer than ours, and so to see 85 00:04:51,160 --> 00:04:54,680 Speaker 1: one dies pretty unusual. We'll be talking talking about supernovas 86 00:04:54,680 --> 00:04:57,520 Speaker 1: and what how what causes a supernova and how that works. 87 00:04:57,920 --> 00:05:00,960 Speaker 1: But it's basically the biggest explode shin you can have 88 00:05:01,040 --> 00:05:04,039 Speaker 1: in space? Right? Is that true? The whole universe? That's 89 00:05:04,080 --> 00:05:07,039 Speaker 1: the biggest explosion that happens. It's the biggest explosion we've 90 00:05:07,080 --> 00:05:09,960 Speaker 1: seen so far. I mean, the stars are one of 91 00:05:10,000 --> 00:05:12,480 Speaker 1: the biggest things out there. I guess you can imagine 92 00:05:12,480 --> 00:05:15,400 Speaker 1: a galaxy exploding, but it's hard to see how that 93 00:05:15,440 --> 00:05:18,320 Speaker 1: would happen. A galaxy nova. Nobody's ever seen that yet. 94 00:05:18,360 --> 00:05:24,920 Speaker 1: What would you call that an uber nova or over nova? 95 00:05:25,960 --> 00:05:28,960 Speaker 1: But I guess maybe it's the biggest explosion because you know, 96 00:05:29,040 --> 00:05:31,839 Speaker 1: stars are some of the most you know, energy pack 97 00:05:31,960 --> 00:05:34,960 Speaker 1: things out there, right, I mean that that can explode 98 00:05:35,040 --> 00:05:37,279 Speaker 1: like you don't see a black hole exploding. You don't 99 00:05:37,320 --> 00:05:40,479 Speaker 1: yet see black holes exploding. That would be fascinating. And yeah, 100 00:05:40,560 --> 00:05:42,960 Speaker 1: the key to having a big explosion is not just 101 00:05:43,360 --> 00:05:46,560 Speaker 1: being massive, having a lot of energy, but releasing it 102 00:05:46,720 --> 00:05:49,880 Speaker 1: very very rapidly. Right, That's basically what an explosion is. 103 00:05:49,960 --> 00:05:52,400 Speaker 1: It's like it's like a bomb. You want to deposit 104 00:05:52,440 --> 00:05:54,880 Speaker 1: a lot of energy and you want to do really quickly, 105 00:05:55,200 --> 00:05:57,279 Speaker 1: so you got a shock wave of action. And that's 106 00:05:57,320 --> 00:06:00,240 Speaker 1: the thing that makes supernova is exciting that they happen ly. 107 00:06:00,279 --> 00:06:02,080 Speaker 1: It also is the thing that makes them hard to 108 00:06:02,160 --> 00:06:05,240 Speaker 1: understand and hard to spot because we don't know it 109 00:06:05,360 --> 00:06:08,840 Speaker 1: precisely what causes the star to go supernova, and they 110 00:06:08,880 --> 00:06:11,800 Speaker 1: don't happen that often, so it's pretty rare to see 111 00:06:11,839 --> 00:06:14,640 Speaker 1: one's start to go oh wow. Really, we don't know 112 00:06:14,680 --> 00:06:17,679 Speaker 1: what cosses these supernovas. No, we have some general sense 113 00:06:17,720 --> 00:06:20,080 Speaker 1: for what happens during the supernova, and we'll dig into 114 00:06:20,080 --> 00:06:23,119 Speaker 1: it on today's podcast. But what makes it go now 115 00:06:23,200 --> 00:06:26,440 Speaker 1: and not next week. To predict when an individual star 116 00:06:26,520 --> 00:06:28,920 Speaker 1: will go supernova is not something we know how to do. 117 00:06:29,080 --> 00:06:31,560 Speaker 1: Nobody's pressing a switch that you can see. Yeah, they 118 00:06:31,560 --> 00:06:33,760 Speaker 1: don't annow it's a big countdown like NASA. You know, 119 00:06:36,560 --> 00:06:40,719 Speaker 1: t's not taking time bomb. No, and astronomers would love 120 00:06:40,760 --> 00:06:43,839 Speaker 1: to see a star like five seconds before superno, one 121 00:06:43,880 --> 00:06:47,480 Speaker 1: second before supernova the first moments, you know, that would 122 00:06:47,480 --> 00:06:49,720 Speaker 1: be fascinating, so you can catch it as it as 123 00:06:49,800 --> 00:06:52,919 Speaker 1: it's happening. Yeah, And there's actually a guy who was 124 00:06:53,000 --> 00:06:56,120 Speaker 1: watching the skies in two thousand and sixteen, an astronomer, 125 00:06:56,240 --> 00:06:59,239 Speaker 1: an amateur astronomer. He was just happen to be looking 126 00:06:59,279 --> 00:07:02,040 Speaker 1: at one star her through his telescope and he saw 127 00:07:02,080 --> 00:07:05,400 Speaker 1: it go supernova, like in real time. Wow. What are 128 00:07:05,400 --> 00:07:07,680 Speaker 1: the chances of that? Well, they're pretty low because it's 129 00:07:07,720 --> 00:07:10,400 Speaker 1: actually not that many stars that will go supernova, Like, 130 00:07:10,480 --> 00:07:13,360 Speaker 1: not every star ends up in a supernova. And of 131 00:07:13,400 --> 00:07:16,560 Speaker 1: course stars lived for a really long long time, and 132 00:07:16,600 --> 00:07:18,960 Speaker 1: so they calculated the odds is like one in ten 133 00:07:19,040 --> 00:07:21,320 Speaker 1: million or one in a hundred million that if you're 134 00:07:21,320 --> 00:07:23,360 Speaker 1: looking at a star or through a telescope, that you'll 135 00:07:23,400 --> 00:07:26,760 Speaker 1: be watching it go supernova. Oh. So this person was 136 00:07:26,880 --> 00:07:29,800 Speaker 1: looking at the star through his telescope or her telescope 137 00:07:29,840 --> 00:07:31,800 Speaker 1: and it went supernova as he was looking at it. 138 00:07:31,880 --> 00:07:33,400 Speaker 1: As he was looking at it. Now, of course this 139 00:07:33,520 --> 00:07:35,960 Speaker 1: time delay went supernova a long long time ago, but 140 00:07:36,280 --> 00:07:40,080 Speaker 1: the images from that supernova arrived on Earth as his 141 00:07:40,160 --> 00:07:43,880 Speaker 1: eyeballs were pointed at it. Oh wow, And so how 142 00:07:43,920 --> 00:07:45,920 Speaker 1: did he prove this. Did he have a about his 143 00:07:45,960 --> 00:07:49,040 Speaker 1: cell phone and took a picture of it? Yea, all 144 00:07:49,080 --> 00:07:53,600 Speaker 1: good amateur astronomers have cameras attached to their telescopes, so 145 00:07:53,640 --> 00:07:56,200 Speaker 1: he snapped some photos. Then, of course he alerted astronomers 146 00:07:56,280 --> 00:07:58,400 Speaker 1: who all pointed their telescopes at it to try to 147 00:07:58,480 --> 00:08:00,680 Speaker 1: catch a glimpse of the first moment to the star 148 00:08:00,800 --> 00:08:03,440 Speaker 1: going nova. What is that true? He actually took pictures 149 00:08:03,440 --> 00:08:06,960 Speaker 1: of it? Oh yeah, Oh wow, that's pretty interesting. Wow. 150 00:08:07,240 --> 00:08:09,560 Speaker 1: And so supernovas are sort of famous, like people have 151 00:08:09,640 --> 00:08:11,720 Speaker 1: heard of them. People know that they're a thing. They're 152 00:08:11,840 --> 00:08:15,280 Speaker 1: pretty dramatic. Their pr campaigns have been pretty good. Yeah, 153 00:08:15,360 --> 00:08:18,600 Speaker 1: they're there's sort of in the general consciousness for sure, 154 00:08:19,280 --> 00:08:21,880 Speaker 1: of I think culture and society. I mean, everyone knows 155 00:08:21,960 --> 00:08:24,480 Speaker 1: him as his stars exploding. Yeah, but I was curious, 156 00:08:24,560 --> 00:08:27,280 Speaker 1: you know, how much did people actually know about a supernova? 157 00:08:27,320 --> 00:08:29,400 Speaker 1: Did they know what really happens inside? Do they know 158 00:08:29,440 --> 00:08:33,240 Speaker 1: what causes it? Do they know whether we understand supernovas? 159 00:08:33,280 --> 00:08:35,679 Speaker 1: So I walked around campus here at you see Irvine, 160 00:08:35,720 --> 00:08:39,319 Speaker 1: and I asked folks what they knew about supernovas. Yeah, 161 00:08:39,440 --> 00:08:41,719 Speaker 1: so think about it for a second. You've probably heard 162 00:08:41,760 --> 00:08:44,720 Speaker 1: of supernovas, But do you know what causes them and 163 00:08:44,800 --> 00:08:47,920 Speaker 1: how they actually explode? Here's what people had to say. 164 00:08:48,000 --> 00:08:50,240 Speaker 1: I guess it's something to do with the star exploding. 165 00:08:50,760 --> 00:08:55,120 Speaker 1: When a star explodes, What makes it happened? Um, the 166 00:08:55,200 --> 00:08:59,560 Speaker 1: death of the star. Supernovas usually like an exploding star, right, 167 00:09:00,200 --> 00:09:04,320 Speaker 1: so what makes its age? Are you going to explode 168 00:09:04,320 --> 00:09:08,760 Speaker 1: when you get over? Who knows? I know that supermanovas 169 00:09:08,880 --> 00:09:11,080 Speaker 1: are when a star reaches the end of its life 170 00:09:11,360 --> 00:09:15,719 Speaker 1: and eventually the force of gravity overcomes the push from 171 00:09:15,760 --> 00:09:18,959 Speaker 1: the inside of the star and it collapses and then explodes. 172 00:09:19,160 --> 00:09:21,440 Speaker 1: I know they're in space and it's is it? Is 173 00:09:21,440 --> 00:09:24,520 Speaker 1: it when a star like implodes or something more? I 174 00:09:24,559 --> 00:09:28,840 Speaker 1: know that they are the final stage and stars. Okay, 175 00:09:28,840 --> 00:09:33,080 Speaker 1: what makes it happen? Eventually, the the it becomes too dense, 176 00:09:33,400 --> 00:09:35,600 Speaker 1: the elements that it creates in the in the middle. 177 00:09:35,840 --> 00:09:39,120 Speaker 1: At that point it collapses in on itself. And there's 178 00:09:39,120 --> 00:09:41,240 Speaker 1: a few things that can happen. But a supernova is 179 00:09:41,280 --> 00:09:45,640 Speaker 1: one of them. A supernova No, I don't alright? Cool, 180 00:09:45,679 --> 00:09:48,400 Speaker 1: So I think it sounds like everyone knows what it means, 181 00:09:48,400 --> 00:09:51,559 Speaker 1: Like it means the death or the explosion of a star. Yeah, 182 00:09:51,640 --> 00:09:53,679 Speaker 1: they knew that it marks the end of the life 183 00:09:53,679 --> 00:09:56,160 Speaker 1: of a star, but a few people have really a 184 00:09:56,200 --> 00:09:58,920 Speaker 1: sense for like what's going on inside the supernova? What 185 00:09:59,080 --> 00:10:02,439 Speaker 1: makes it happen? Why do stars die that way? Why 186 00:10:02,440 --> 00:10:04,920 Speaker 1: do stars die at all? Why don't they just burn forever? 187 00:10:05,080 --> 00:10:07,079 Speaker 1: So it's a big e explosion in space. And you're 188 00:10:07,080 --> 00:10:10,800 Speaker 1: saying it's rare, so only about one to three supernova's 189 00:10:11,240 --> 00:10:14,240 Speaker 1: per century or something like that in a typical galaxy. Yeah, 190 00:10:14,280 --> 00:10:16,880 Speaker 1: we have seen a lot of supernovas from Earth, but 191 00:10:16,960 --> 00:10:20,120 Speaker 1: almost all of them have been in other galaxies. And 192 00:10:20,200 --> 00:10:23,600 Speaker 1: that's because most stars will not go supernova. In a 193 00:10:23,679 --> 00:10:26,280 Speaker 1: galaxy like the Milky Way that has about a hundred 194 00:10:26,320 --> 00:10:30,800 Speaker 1: billion stars, only about one or two, maybe three will 195 00:10:30,840 --> 00:10:34,800 Speaker 1: go supernova in a hundred years. So it's not it's 196 00:10:34,800 --> 00:10:38,120 Speaker 1: pretty rare. Most stars don't go supernova. Most stars do 197 00:10:38,160 --> 00:10:40,720 Speaker 1: not go supernova. The fact that we've seen hundreds is 198 00:10:40,760 --> 00:10:43,600 Speaker 1: only because there are so many stars and so many 199 00:10:43,640 --> 00:10:46,360 Speaker 1: galaxies out there. But you know, we're lucky and we're 200 00:10:46,360 --> 00:10:49,079 Speaker 1: glad actually that they're not a lot of supernovas, because 201 00:10:49,080 --> 00:10:53,040 Speaker 1: they're pretty devastating. Oh I see, So if a supernova 202 00:10:53,080 --> 00:10:56,000 Speaker 1: goes off in a galaxy far away, we'll will actually 203 00:10:56,559 --> 00:10:59,280 Speaker 1: see it, like it'll outshine the whole galaxy and we'll 204 00:10:59,320 --> 00:11:02,160 Speaker 1: see it, uh, you know, take over the light from 205 00:11:02,200 --> 00:11:04,920 Speaker 1: the galaxy. That's right. It's a really dramatic event. It 206 00:11:04,960 --> 00:11:07,720 Speaker 1: can be as bright as the entire sum of all 207 00:11:07,800 --> 00:11:10,800 Speaker 1: the light from the rest of the stars in the galaxy. 208 00:11:10,920 --> 00:11:13,600 Speaker 1: And so it's like it like doubles the brightness of 209 00:11:13,600 --> 00:11:16,439 Speaker 1: a galaxy when it happens. And the most amazing thing 210 00:11:16,480 --> 00:11:19,320 Speaker 1: is that most of the energy from the supernova doesn't 211 00:11:19,360 --> 00:11:21,439 Speaker 1: even come out in the form of light, so you're 212 00:11:21,440 --> 00:11:25,400 Speaker 1: seeing a tiny fraction of this incredible explosion in the 213 00:11:25,480 --> 00:11:27,960 Speaker 1: visual spectrum. So if you see if you're looking at 214 00:11:27,960 --> 00:11:30,360 Speaker 1: a galaxy at any point and you see it certainly 215 00:11:30,440 --> 00:11:32,880 Speaker 1: bright up, it's because of a supernova inside of it, 216 00:11:33,080 --> 00:11:37,600 Speaker 1: like one of its hundred billion stars went boom. Yeah, precisely. Well, 217 00:11:37,679 --> 00:11:39,920 Speaker 1: let's get into it, Daniel, all right, um, and explain. 218 00:11:40,040 --> 00:11:44,200 Speaker 1: Let's explain to people what a supernova is. I guess 219 00:11:44,200 --> 00:11:47,200 Speaker 1: what's the technical definition of a supernova. Yeah, so technically 220 00:11:47,200 --> 00:11:49,920 Speaker 1: a supernova is the end of the life of some 221 00:11:50,080 --> 00:11:53,160 Speaker 1: kinds of stars. Now not all stars. In fact, most 222 00:11:53,240 --> 00:11:56,880 Speaker 1: stars will not go supernova. But it's essentially the star 223 00:11:56,960 --> 00:11:59,960 Speaker 1: explodes and it sends out most of the energy that's 224 00:12:00,000 --> 00:12:02,840 Speaker 1: stored inside of it out into space in the form 225 00:12:02,920 --> 00:12:06,880 Speaker 1: of electromagnetic radiation, so visible light, which is a tiny fraction, 226 00:12:07,480 --> 00:12:10,880 Speaker 1: and an enormous number of neutrinos, just like gobs and 227 00:12:10,960 --> 00:12:14,760 Speaker 1: gobs and gobs of neutrinos, and then also an enormous 228 00:12:14,760 --> 00:12:17,160 Speaker 1: amount of matter. This is like shock wave of just 229 00:12:17,320 --> 00:12:21,640 Speaker 1: stuff that gets spewed across the universe, like the shrapnel 230 00:12:21,640 --> 00:12:24,360 Speaker 1: and the grenade. Yeah, like the shrapnel and the grenade. 231 00:12:24,400 --> 00:12:27,040 Speaker 1: And it's good that that happens because that goes out 232 00:12:27,040 --> 00:12:29,760 Speaker 1: and that seeds other stars to form, and it spreads 233 00:12:29,960 --> 00:12:32,800 Speaker 1: the heavy metals that were burned inside that star out 234 00:12:32,840 --> 00:12:34,760 Speaker 1: into the universe, so you can get interesting things like 235 00:12:34,800 --> 00:12:37,480 Speaker 1: a rocky planets then life on them. Well that's interesting. 236 00:12:37,520 --> 00:12:40,920 Speaker 1: So it's not Supernova is not like an accident that 237 00:12:40,960 --> 00:12:43,240 Speaker 1: happens to a star. It thought like um, a star 238 00:12:43,280 --> 00:12:45,600 Speaker 1: is suddenly gets out of balance. It's like it's like 239 00:12:45,640 --> 00:12:48,480 Speaker 1: in the DNA of the star. You know, like once 240 00:12:48,559 --> 00:12:50,120 Speaker 1: you once you know what kind of story you are, 241 00:12:50,320 --> 00:12:53,400 Speaker 1: you will most likely go supernova or if you know 242 00:12:53,480 --> 00:12:55,800 Speaker 1: the kind of star you know you'll never get you'll 243 00:12:55,840 --> 00:12:58,600 Speaker 1: never go supernova. Yeah, it's sort of like that, and 244 00:12:58,640 --> 00:13:01,920 Speaker 1: it's not totally under good, but it's something like if 245 00:13:01,960 --> 00:13:04,280 Speaker 1: you know how much master is to a star and 246 00:13:04,360 --> 00:13:06,240 Speaker 1: you know what it's made out of, Like did it 247 00:13:06,360 --> 00:13:08,839 Speaker 1: start just from burning hydrogen because you're one of the 248 00:13:08,880 --> 00:13:12,040 Speaker 1: first stars in the universe, or do you already collect 249 00:13:12,080 --> 00:13:14,520 Speaker 1: the burning remnants of other dead stars and so you 250 00:13:14,559 --> 00:13:17,959 Speaker 1: have helium and oxygen and nitrogen and carbon and all 251 00:13:18,000 --> 00:13:20,520 Speaker 1: that stuff already. If you know that starting point, you 252 00:13:20,520 --> 00:13:23,520 Speaker 1: can almost always predict the life cycle of a star, 253 00:13:24,160 --> 00:13:26,520 Speaker 1: including whether it's going to become a black hole or 254 00:13:26,559 --> 00:13:29,160 Speaker 1: a neutron star, or goes supernova, become a white dwarf 255 00:13:29,240 --> 00:13:32,320 Speaker 1: or whatever. That's basically what determines it is like how 256 00:13:32,320 --> 00:13:34,720 Speaker 1: big a scoop of stuff did you get of the universe? 257 00:13:34,800 --> 00:13:37,480 Speaker 1: And what's in that scoop? Wow? And that the terms 258 00:13:37,559 --> 00:13:39,920 Speaker 1: your your whole life cycle. If you're a star, like 259 00:13:40,200 --> 00:13:44,120 Speaker 1: you're born and everyone already knows how you're gonna die. 260 00:13:44,760 --> 00:13:46,480 Speaker 1: Here's a baby. Oh, this baby is going to be 261 00:13:46,559 --> 00:13:50,760 Speaker 1: a rock star and it's going to you know, shine brightly, 262 00:13:50,800 --> 00:13:52,240 Speaker 1: but then it's going to go out in a blaze 263 00:13:52,240 --> 00:13:55,160 Speaker 1: of glory when he or sheet turns thirty two. Stars 264 00:13:55,160 --> 00:13:58,760 Speaker 1: are not nearly as exciting and variable as people are. Right. 265 00:13:59,080 --> 00:14:02,080 Speaker 1: They're much bigger, and they're much more dramatic, but they're 266 00:14:02,080 --> 00:14:05,040 Speaker 1: also simpler, and also they don't really interact with each other. 267 00:14:05,160 --> 00:14:07,840 Speaker 1: Like a star is pretty isolated. It's got its own 268 00:14:07,840 --> 00:14:09,720 Speaker 1: little pocket of stuff and it just sits there and 269 00:14:09,760 --> 00:14:12,200 Speaker 1: burns it until it can't burn it anymore. We know 270 00:14:12,240 --> 00:14:14,960 Speaker 1: it's gonna go supernova, but you can't predict when it's 271 00:14:15,000 --> 00:14:17,439 Speaker 1: going to go supernova. Yeah, these stars have some something 272 00:14:17,440 --> 00:14:20,000 Speaker 1: of a variable lifetime, and you know these events, the 273 00:14:20,040 --> 00:14:23,520 Speaker 1: supernov event happens really quickly. Remember that the like the 274 00:14:23,520 --> 00:14:27,400 Speaker 1: time scale for stars can be millions and billions of years, 275 00:14:27,680 --> 00:14:30,080 Speaker 1: but the supernova events, the time scale for that is 276 00:14:30,240 --> 00:14:35,120 Speaker 1: days and so days, days, and so it happens really quickly, 277 00:14:35,200 --> 00:14:38,800 Speaker 1: especially the first bit the explosion. We're talking seconds and minutes, 278 00:14:39,160 --> 00:14:41,240 Speaker 1: and so what triggers that to happen? Is it like 279 00:14:41,520 --> 00:14:44,440 Speaker 1: a clock that ticking down. Eventually it's just gonna happen 280 00:14:44,480 --> 00:14:47,040 Speaker 1: like that. You could predict it a million or a 281 00:14:47,080 --> 00:14:49,520 Speaker 1: billion years in advance, if you knew well enough. What 282 00:14:49,680 --> 00:14:52,160 Speaker 1: was happening inside the star or is there some like 283 00:14:52,200 --> 00:14:55,400 Speaker 1: quantum mechanical randomness that's happening, or is it triggered by 284 00:14:55,440 --> 00:14:58,840 Speaker 1: some external event, like the star becomes really fragile and 285 00:14:58,880 --> 00:15:01,160 Speaker 1: then you know, a path seeing shock away from something 286 00:15:01,200 --> 00:15:04,120 Speaker 1: else makes it go. We just don't really understand those 287 00:15:04,160 --> 00:15:08,320 Speaker 1: moments or you know, um like a planet falls into 288 00:15:08,360 --> 00:15:11,880 Speaker 1: it and that triggers it. Perhaps, Yeah, there are stars 289 00:15:11,920 --> 00:15:15,240 Speaker 1: like that that do get triggers from in falling material, 290 00:15:15,280 --> 00:15:17,840 Speaker 1: but we don't know exactly like when that happens. All right, well, 291 00:15:17,920 --> 00:15:20,640 Speaker 1: let's get into the mystery of what triggers supernovas and 292 00:15:20,640 --> 00:15:23,960 Speaker 1: what's actually happening when they explode. But first let's take 293 00:15:23,960 --> 00:15:39,480 Speaker 1: a quick break. Right, So we we've seen a couple 294 00:15:39,520 --> 00:15:43,000 Speaker 1: of these supernovas in the night sky, like without telescopes. Right, 295 00:15:43,080 --> 00:15:48,360 Speaker 1: there's a historical record of supernovas and in humanity's history. Yeah, 296 00:15:48,400 --> 00:15:51,760 Speaker 1: it's a big event in the night sky when something blows. 297 00:15:52,240 --> 00:15:54,840 Speaker 1: And back before people really understood what stars were, they 298 00:15:54,880 --> 00:15:57,840 Speaker 1: were still interested in looking at them and commenting about them. 299 00:15:57,880 --> 00:15:59,840 Speaker 1: And so you can go back in the historical record 300 00:15:59,840 --> 00:16:03,280 Speaker 1: and can find ancient astronomers writing about this and the 301 00:16:03,400 --> 00:16:08,000 Speaker 1: earliest one. It's called h B nine is from b 302 00:16:08,080 --> 00:16:11,800 Speaker 1: C and we see this an ancient ancient texts. They 303 00:16:11,840 --> 00:16:14,480 Speaker 1: talk about the appearance of a new star in the sky. 304 00:16:14,560 --> 00:16:16,600 Speaker 1: So they just called it HB nine. What were those 305 00:16:16,640 --> 00:16:20,440 Speaker 1: ancient people thinking they had acronyms and numbers for I 306 00:16:20,480 --> 00:16:22,440 Speaker 1: don't know, we don't know who was We know it 307 00:16:22,520 --> 00:16:26,560 Speaker 1: was some unnamed Indian astronomers. We call it h B nine. 308 00:16:26,640 --> 00:16:28,360 Speaker 1: But you know they wrote about it as a as 309 00:16:28,400 --> 00:16:30,560 Speaker 1: a new object in the sky. Well, what would we 310 00:16:30,640 --> 00:16:32,800 Speaker 1: see if if I happened to be looking at the 311 00:16:32,920 --> 00:16:36,520 Speaker 1: nice guy and a Superno, what just happened to you know, 312 00:16:36,640 --> 00:16:38,720 Speaker 1: occur while I'm looking at this guy? What would I see? 313 00:16:38,720 --> 00:16:42,680 Speaker 1: Would I see a star suddenly grow bright and fill 314 00:16:42,800 --> 00:16:44,720 Speaker 1: the sky with light? Or would just would it just 315 00:16:44,760 --> 00:16:46,800 Speaker 1: be a star that gets a little bit brighter. Well, 316 00:16:46,840 --> 00:16:49,120 Speaker 1: it depends on how close it is. Of course, the 317 00:16:49,120 --> 00:16:52,440 Speaker 1: star is gonna get millions and millions or even billions 318 00:16:52,480 --> 00:16:55,720 Speaker 1: of times brighter than it normally is. Like, would it 319 00:16:55,720 --> 00:16:58,400 Speaker 1: be dangerous to look at it? Yes, if you are 320 00:16:58,480 --> 00:17:02,120 Speaker 1: looking at a star that's going supernova in our galaxy, 321 00:17:02,560 --> 00:17:04,439 Speaker 1: it could be very dangerous. I mean, you could fry 322 00:17:04,480 --> 00:17:06,680 Speaker 1: all life on Earth. That's kind of dangerous. So yes, 323 00:17:06,760 --> 00:17:11,080 Speaker 1: looking at it would be bad, all right, Um, and 324 00:17:11,119 --> 00:17:14,200 Speaker 1: then what would would I see it go bright for 325 00:17:14,240 --> 00:17:16,359 Speaker 1: like a few seconds, for a few hours, for a 326 00:17:16,400 --> 00:17:19,440 Speaker 1: few days. So the light curve of a supernova looks 327 00:17:19,480 --> 00:17:22,280 Speaker 1: like very rapidly getting brighter and brighter over the period 328 00:17:22,320 --> 00:17:25,280 Speaker 1: of a few days and then gradually fading over the 329 00:17:25,320 --> 00:17:27,359 Speaker 1: period of a few weeks outter a few months. So 330 00:17:27,400 --> 00:17:30,280 Speaker 1: it wouldn't be like a sudden flash. You would get 331 00:17:30,280 --> 00:17:31,919 Speaker 1: a little bit of warning. You would get brighter and 332 00:17:31,960 --> 00:17:34,000 Speaker 1: brighter and brighter over a couple of days. Yeah, And 333 00:17:34,000 --> 00:17:37,240 Speaker 1: you can actually get a warning before the flash arrives 334 00:17:37,560 --> 00:17:42,160 Speaker 1: because we see neutrinos arrive before the photons. Neutrinos get 335 00:17:42,200 --> 00:17:45,120 Speaker 1: here first and they tell you watch out a supernova's 336 00:17:45,160 --> 00:17:48,680 Speaker 1: coming three hours later. Oh really, it's like an early 337 00:17:48,720 --> 00:17:51,280 Speaker 1: warning system, it is. And you can actually sign up 338 00:17:51,440 --> 00:17:55,400 Speaker 1: for an early warning emails there instead of neutrino detectors 339 00:17:55,440 --> 00:17:57,760 Speaker 1: here on Earth, and you can go to a website 340 00:17:57,760 --> 00:18:00,560 Speaker 1: called s News and they will send you an email 341 00:18:00,600 --> 00:18:03,879 Speaker 1: when they detect a big flux of neutrinos coming to 342 00:18:03,920 --> 00:18:06,000 Speaker 1: the Earth. Oh wow, cool, So that you can run 343 00:18:06,000 --> 00:18:09,440 Speaker 1: outside and not look at it, just so you can know. 344 00:18:09,640 --> 00:18:12,520 Speaker 1: Man who doesn't want to know, so you can go 345 00:18:12,560 --> 00:18:15,280 Speaker 1: down down to your bunker and not look up at 346 00:18:15,280 --> 00:18:17,439 Speaker 1: the sky like our president. It might mean that in 347 00:18:17,480 --> 00:18:21,000 Speaker 1: three minutes you are that's going to fry. Yeah, it 348 00:18:21,000 --> 00:18:23,000 Speaker 1: could be. That would be the first warning. And the 349 00:18:23,040 --> 00:18:25,679 Speaker 1: neutrinos get here first because they're the only ones that 350 00:18:25,720 --> 00:18:29,080 Speaker 1: can escape the star. Photons, of course, travel faster than 351 00:18:29,080 --> 00:18:33,000 Speaker 1: neutrinos because neutrinos are not massless like photons are. But 352 00:18:33,080 --> 00:18:35,760 Speaker 1: neutrinos can fly out of the star, whereas the photons 353 00:18:35,760 --> 00:18:39,080 Speaker 1: get absorbed inside the star as it's happening, and so 354 00:18:39,200 --> 00:18:42,080 Speaker 1: photons don't leave the supernova until like the shock wave 355 00:18:42,200 --> 00:18:44,840 Speaker 1: reaches the surface, which is a few hours after the 356 00:18:44,840 --> 00:18:48,840 Speaker 1: beginning of the explosion. Yeah, the the the explosion itself. Yeah, 357 00:18:48,840 --> 00:18:50,680 Speaker 1: they get sort of reabsorbed, and it takes a little 358 00:18:50,720 --> 00:18:53,600 Speaker 1: while for the photons that will reach Earth to be omitted. 359 00:18:54,200 --> 00:18:56,240 Speaker 1: So that's why the neutrinos get here first, not because 360 00:18:56,280 --> 00:18:58,879 Speaker 1: they're faster, but because they sort of left first and 361 00:18:58,920 --> 00:19:02,840 Speaker 1: didn't get socked. All right, Well, let's get into what's 362 00:19:02,880 --> 00:19:05,320 Speaker 1: happening here. It's super fun to think about this stuff, 363 00:19:05,359 --> 00:19:07,520 Speaker 1: you know, because it's a it's a dramatic event, and 364 00:19:07,600 --> 00:19:10,320 Speaker 1: so people really like thinking not just about how stars 365 00:19:10,359 --> 00:19:12,439 Speaker 1: form and how they burned, but how they blow up 366 00:19:12,440 --> 00:19:15,080 Speaker 1: and what makes it happen. And as far as we know, 367 00:19:15,119 --> 00:19:18,600 Speaker 1: there are sort of two totally different kinds of supernovas 368 00:19:18,640 --> 00:19:21,600 Speaker 1: that happened. Both of these kinds of supernova reflect this 369 00:19:21,880 --> 00:19:26,840 Speaker 1: classic Titanic battle between gravity and fusion. In one case, 370 00:19:27,160 --> 00:19:30,199 Speaker 1: fusion winds and in the other case, it's gravity that 371 00:19:30,240 --> 00:19:32,679 Speaker 1: comes out on top. The first one we call a 372 00:19:32,800 --> 00:19:35,960 Speaker 1: runaway fusion, and the second one is probably better well known, 373 00:19:36,080 --> 00:19:39,119 Speaker 1: is the core collapse supernova. But they're really very different 374 00:19:39,400 --> 00:19:42,719 Speaker 1: kinds of events. Would you classify them both as supernovas? Like, 375 00:19:43,040 --> 00:19:45,600 Speaker 1: it's still a star exploding, it just happens in in 376 00:19:45,760 --> 00:19:48,520 Speaker 1: very different ways. Yeah, And there's lots of different categories 377 00:19:48,560 --> 00:19:50,359 Speaker 1: of supernovas. You might have heard of type one A, 378 00:19:50,560 --> 00:19:54,160 Speaker 1: type two, type two C or whatever those described basically 379 00:19:54,200 --> 00:19:56,680 Speaker 1: what they look like in the sky, what the sort 380 00:19:56,680 --> 00:19:59,160 Speaker 1: of energy spectrum from them looks like. But there's two 381 00:19:59,200 --> 00:20:02,600 Speaker 1: fundamental mech isms, this runaway fusion and this core collapse. 382 00:20:02,800 --> 00:20:05,040 Speaker 1: That's cool, Let's let's get into the first one here 383 00:20:05,119 --> 00:20:09,520 Speaker 1: runaway fusion. That sounds like um, like an experiment that 384 00:20:09,680 --> 00:20:11,680 Speaker 1: got away from you. I thought you were gonna say 385 00:20:11,760 --> 00:20:15,560 Speaker 1: it sounds like a physics based romcom movie, Julia Roberts. 386 00:20:15,640 --> 00:20:18,440 Speaker 1: So this is what happens when a star. It sort 387 00:20:18,480 --> 00:20:21,240 Speaker 1: of has like a resurgence. It's a star that's had 388 00:20:21,280 --> 00:20:25,040 Speaker 1: its day and then sort of died, and then it 389 00:20:25,119 --> 00:20:27,679 Speaker 1: has a bit of a comeback, really like it had 390 00:20:27,680 --> 00:20:30,719 Speaker 1: a nice long life as a regular star, and it 391 00:20:30,760 --> 00:20:34,240 Speaker 1: was already waning, but then it rallied at the end precisely, 392 00:20:34,640 --> 00:20:36,400 Speaker 1: and it's sort of in retirement and then it sort 393 00:20:36,440 --> 00:20:40,000 Speaker 1: of brought back for one last explosion. And so what 394 00:20:40,119 --> 00:20:42,600 Speaker 1: happens here is you have a very normal kind of star, 395 00:20:42,720 --> 00:20:46,720 Speaker 1: a big star, a red giant. And remember what's happening 396 00:20:46,800 --> 00:20:49,760 Speaker 1: inside a star is that gravity is pushing in, it's 397 00:20:49,760 --> 00:20:54,480 Speaker 1: squeezing everything, and because of all that pressure, you're getting fusion. 398 00:20:54,800 --> 00:20:58,359 Speaker 1: You're turning hydrogen into helium and helium and heavier stuff 399 00:20:58,400 --> 00:21:01,000 Speaker 1: and heavier stuff into even heavy your stuff. Right, You're 400 00:21:01,040 --> 00:21:03,919 Speaker 1: you're squeezing stuff together so much it's it's burning and 401 00:21:03,960 --> 00:21:07,480 Speaker 1: exploding and fusion ng and releasing energy at the same time. 402 00:21:07,640 --> 00:21:10,240 Speaker 1: That's right. And you might wonder, like, why doesn't an 403 00:21:10,240 --> 00:21:13,760 Speaker 1: object like that immediately collapse into a black hole. And 404 00:21:13,800 --> 00:21:16,720 Speaker 1: the reason is that there's outwards pressure and that pressure 405 00:21:16,720 --> 00:21:20,080 Speaker 1: comes from the explosions, right, it's burning, that's shooting stuff out. 406 00:21:20,560 --> 00:21:23,440 Speaker 1: And also because matter doesn't like to get squeezed that far, 407 00:21:23,880 --> 00:21:26,520 Speaker 1: so you know, you squeeze stuff together, it doesn't like 408 00:21:26,640 --> 00:21:29,520 Speaker 1: to compress, so there's some pressure back out and that's 409 00:21:29,520 --> 00:21:32,280 Speaker 1: what keeps the star alive. Is this balance between gravity 410 00:21:32,320 --> 00:21:36,960 Speaker 1: squeezing in and pressure pushing out to keep it alive. Right. 411 00:21:37,000 --> 00:21:39,760 Speaker 1: It's kind of like if you're squeezing a bag of 412 00:21:39,240 --> 00:21:43,040 Speaker 1: of of corn kernels, like you would squeeze them, but 413 00:21:43,040 --> 00:21:45,000 Speaker 1: that would someone would be popping at the same time, 414 00:21:45,040 --> 00:21:48,600 Speaker 1: so you wouldn't automatically just collapse or explode. You might 415 00:21:48,680 --> 00:21:51,240 Speaker 1: reach this balance, which is a star. I've heard of fusion, 416 00:21:51,320 --> 00:21:53,919 Speaker 1: and I've heard of cold fusion, but I've never, until today, 417 00:21:54,280 --> 00:21:59,359 Speaker 1: heard of corn fusion. I think you might be a 418 00:21:59,400 --> 00:22:03,360 Speaker 1: brand of pop corn. It's a brand of popcorn physics 419 00:22:03,359 --> 00:22:07,000 Speaker 1: snacks corn fusions, right, Yeah, there you go. Well, I'm 420 00:22:07,000 --> 00:22:09,200 Speaker 1: waiting for candy corn fusion. But that's why I think 421 00:22:09,200 --> 00:22:11,000 Speaker 1: that's what you mean. It's like you squeeze something and 422 00:22:11,040 --> 00:22:13,200 Speaker 1: then it pops. And so if you have a whole 423 00:22:13,240 --> 00:22:14,960 Speaker 1: bunch of that and you're squeezing them, David, some of 424 00:22:14,960 --> 00:22:17,280 Speaker 1: them keep popping until you it's hard to sort of 425 00:22:17,320 --> 00:22:19,359 Speaker 1: like keep compressing them. I know we're supposed to be 426 00:22:19,359 --> 00:22:22,040 Speaker 1: talking about supernovous, but now I'm desperately curious. What would 427 00:22:22,080 --> 00:22:25,440 Speaker 1: happen if you actually squeeze that much popcorn? Would they pop? 428 00:22:25,480 --> 00:22:28,080 Speaker 1: I bet they would. Bet you'd be heating and pressuring, 429 00:22:28,119 --> 00:22:31,920 Speaker 1: and uh yeah, you might get a self sustaining corn reaction. 430 00:22:34,040 --> 00:22:37,040 Speaker 1: That's exactly the idea. And what happens inside the stars 431 00:22:37,160 --> 00:22:40,120 Speaker 1: that you're fusing the stuff and it's making heavier stuff, 432 00:22:40,440 --> 00:22:43,120 Speaker 1: and that heavier stuff can then, if you're big enough, 433 00:22:43,160 --> 00:22:46,359 Speaker 1: and if you're hot enough, can also get squeezed and 434 00:22:46,480 --> 00:22:49,720 Speaker 1: burned and fused. But as the stuff gets heavier and heavier, 435 00:22:49,800 --> 00:22:53,560 Speaker 1: you need higher and higher temperatures to keep the reaction going. Oh, 436 00:22:53,600 --> 00:22:55,720 Speaker 1: I see, at some point you sort of run out 437 00:22:55,720 --> 00:22:57,720 Speaker 1: of fuel, Right, at some point you can't keep this 438 00:22:57,800 --> 00:23:00,359 Speaker 1: up forever. You can't keep it up forever. And for 439 00:23:00,400 --> 00:23:02,760 Speaker 1: some kind of stars, the ones we're talking about red giants, 440 00:23:02,960 --> 00:23:05,840 Speaker 1: they keep burning until they sort of make carbon, and 441 00:23:05,880 --> 00:23:09,000 Speaker 1: it's basically like ash, and so it burns all the fuel, 442 00:23:09,040 --> 00:23:11,920 Speaker 1: but it's not big enough to burn carbon, and that's 443 00:23:11,920 --> 00:23:14,080 Speaker 1: sort of the end of its life. It's like, Okay, 444 00:23:14,080 --> 00:23:16,320 Speaker 1: I'm done. I've burned as far as I could, as 445 00:23:16,359 --> 00:23:18,919 Speaker 1: hot as I could. I reached my pinnacle. Now I'm 446 00:23:18,960 --> 00:23:21,560 Speaker 1: a big ball of hot carbon. I don't have it 447 00:23:21,600 --> 00:23:25,239 Speaker 1: in me to make this carbon fuses. It's just not 448 00:23:25,280 --> 00:23:27,240 Speaker 1: big enough. Like if there were more of it right 449 00:23:27,480 --> 00:23:29,840 Speaker 1: then there would be enough gravitational pressure to squeeze it, 450 00:23:29,880 --> 00:23:32,160 Speaker 1: make it hotter and to ignite that carbon, but there 451 00:23:32,200 --> 00:23:34,520 Speaker 1: isn't and so it just sort of stops there, Okay, 452 00:23:34,560 --> 00:23:36,879 Speaker 1: and then it sort of cools off. Yeah, and what 453 00:23:37,040 --> 00:23:39,120 Speaker 1: you have there or something called a white dwarf, which 454 00:23:39,119 --> 00:23:42,520 Speaker 1: is a fascinating object because it's not fusing anymore. It's 455 00:23:42,560 --> 00:23:45,159 Speaker 1: just sort of like a big hot lump of carbon, 456 00:23:45,440 --> 00:23:48,880 Speaker 1: but it's still glowing. It's glowing because it's super duper hot. 457 00:23:48,920 --> 00:23:52,160 Speaker 1: It's literally white hot carbon. It's glowing in the infrared, 458 00:23:52,160 --> 00:23:54,840 Speaker 1: are also invisible light. In the visible light, yeah, you 459 00:23:54,840 --> 00:23:57,919 Speaker 1: can see white dwarfs, but they're not shining because of fusion. 460 00:23:57,920 --> 00:24:01,120 Speaker 1: They're shining because they're just sort of left overheat from 461 00:24:01,200 --> 00:24:04,439 Speaker 1: their past life when they were fusing. And my favorite 462 00:24:04,440 --> 00:24:07,040 Speaker 1: bit about this is that white dwarfs, because there's no 463 00:24:07,080 --> 00:24:10,480 Speaker 1: more energy coming in there, eventually they're cooling off, and 464 00:24:10,520 --> 00:24:13,200 Speaker 1: eventually they'll just sort of snuff out and turn into 465 00:24:13,240 --> 00:24:15,800 Speaker 1: something called a black dwarf. Oh, I see, if you 466 00:24:16,080 --> 00:24:19,560 Speaker 1: it's red hot, it's white hot, and so that's somebody 467 00:24:19,560 --> 00:24:21,399 Speaker 1: it can just cool off and it just becomes like 468 00:24:21,440 --> 00:24:24,639 Speaker 1: a giant ball of rock. Yeah, but that's never happened 469 00:24:24,720 --> 00:24:27,160 Speaker 1: yet in the universe. We estimate that they would take 470 00:24:27,160 --> 00:24:30,600 Speaker 1: about ten to the fifteen years, that's how hot this 471 00:24:30,680 --> 00:24:33,880 Speaker 1: thing is to cool off. But the universe isn't old 472 00:24:34,000 --> 00:24:36,399 Speaker 1: enough for any black dwarfs to exist. So we have 473 00:24:36,480 --> 00:24:39,119 Speaker 1: this like category of stars that we haven't sort of 474 00:24:39,320 --> 00:24:45,240 Speaker 1: achieved yet, haven't unlocked yet as a universe, like a 475 00:24:45,320 --> 00:24:47,439 Speaker 1: like a video game. Yeah, like a video game, like 476 00:24:47,480 --> 00:24:50,200 Speaker 1: a video game achievement. I see. So we know what's 477 00:24:50,200 --> 00:24:52,120 Speaker 1: going to happen to them, but none, none of none 478 00:24:52,119 --> 00:24:53,639 Speaker 1: of them have actually done it. None of them have 479 00:24:53,640 --> 00:24:56,400 Speaker 1: actually done it, and some small fraction of them sort 480 00:24:56,400 --> 00:24:59,320 Speaker 1: of step off that path, right, So you might be thinking, Okay, 481 00:24:59,359 --> 00:25:01,960 Speaker 1: how's this d up in a supernova? Well, what happens 482 00:25:02,080 --> 00:25:04,000 Speaker 1: is that some of these guys they think they're at 483 00:25:04,000 --> 00:25:06,119 Speaker 1: the end of their career, but then they get a 484 00:25:06,160 --> 00:25:09,280 Speaker 1: sudden dose of extra fuel. To say, for example, you're 485 00:25:09,280 --> 00:25:11,760 Speaker 1: in a binary star system and you're a white dwarf, 486 00:25:12,000 --> 00:25:14,480 Speaker 1: and then the other star starts expanding because it gets 487 00:25:14,480 --> 00:25:17,000 Speaker 1: older and you start sucking up some of its material, 488 00:25:17,680 --> 00:25:20,520 Speaker 1: or for some other reason, a bunch of new material 489 00:25:20,600 --> 00:25:22,959 Speaker 1: comes by and you accrete it and you suck it in. 490 00:25:23,240 --> 00:25:26,320 Speaker 1: Is it that little bit of extra energy or you 491 00:25:26,359 --> 00:25:29,879 Speaker 1: know gravity, It needs to start cooking that carbon precisely, 492 00:25:30,280 --> 00:25:33,040 Speaker 1: and so you get enough extra fuel, right, you get 493 00:25:33,040 --> 00:25:35,000 Speaker 1: all this extra stuff, then you can get hot enough 494 00:25:35,040 --> 00:25:37,359 Speaker 1: to burn carbon. And what happens then is that it 495 00:25:37,440 --> 00:25:41,440 Speaker 1: just goes nuts because it's like volatile, like carbon is volatile. Yeah, 496 00:25:41,440 --> 00:25:43,879 Speaker 1: and this is what we call runaway fusion. It's not 497 00:25:43,960 --> 00:25:48,080 Speaker 1: like very slowly cooking gently over millions and billions of years. 498 00:25:48,440 --> 00:25:51,920 Speaker 1: It's like it burns all that really fast, all at once. 499 00:25:52,119 --> 00:25:53,920 Speaker 1: And in the usual star, you know, you have these 500 00:25:53,920 --> 00:25:57,840 Speaker 1: shells different temperatures and different densities. You have the heavier 501 00:25:57,880 --> 00:25:59,920 Speaker 1: stuff in the middle and the lighter stuff on the outside. 502 00:26:00,119 --> 00:26:02,240 Speaker 1: But here you have basically a ball of carbon with 503 00:26:02,320 --> 00:26:04,520 Speaker 1: some oxygen in it, and it's just ready to go. 504 00:26:04,760 --> 00:26:07,080 Speaker 1: And you deposit enough fuel on that thing and it 505 00:26:07,119 --> 00:26:10,960 Speaker 1: will explode like ten to the forty four jewels, all 506 00:26:11,040 --> 00:26:15,480 Speaker 1: within just a few seconds. It unbinds the star. It's 507 00:26:15,560 --> 00:26:18,320 Speaker 1: really incredible. It really literally like blows up from the 508 00:26:18,359 --> 00:26:21,960 Speaker 1: inside here. Fusion wins and gravity just can't keep the 509 00:26:21,960 --> 00:26:25,600 Speaker 1: star together anymore. Imagine what would happen if every part 510 00:26:25,600 --> 00:26:28,359 Speaker 1: of the Earth suddenly had a huge amount of energy 511 00:26:28,520 --> 00:26:32,480 Speaker 1: like it had, It's enough energy to escape the Earth's gravity. Well, 512 00:26:32,520 --> 00:26:35,040 Speaker 1: that's what happens to this star, Like every element of 513 00:26:35,080 --> 00:26:38,760 Speaker 1: the star now has escape velocity from the star. Gravity 514 00:26:38,840 --> 00:26:43,040 Speaker 1: is overcome and it's just like spews itself over the cosmos. 515 00:26:43,840 --> 00:26:45,760 Speaker 1: So how does it start. It starts in the middle, 516 00:26:45,840 --> 00:26:47,880 Speaker 1: like some of the carbon starts to fuse, and then 517 00:26:47,880 --> 00:26:51,639 Speaker 1: that releases energy with it, which then fuses the carbon 518 00:26:52,240 --> 00:26:54,240 Speaker 1: in the in the outer layers, and so the whole 519 00:26:54,280 --> 00:26:59,320 Speaker 1: thing just suddenly has enough energy to fuse and explode. Yeah, 520 00:26:59,400 --> 00:27:01,320 Speaker 1: and you know, this is sort of the simplified model 521 00:27:01,359 --> 00:27:03,840 Speaker 1: for what we think might be happening and runaway stars, 522 00:27:04,440 --> 00:27:06,760 Speaker 1: and we've seen some of them, and but you know, 523 00:27:06,800 --> 00:27:09,320 Speaker 1: it's hard to really know those first moments because again 524 00:27:09,600 --> 00:27:12,200 Speaker 1: you can only spot the star after it started to 525 00:27:12,240 --> 00:27:15,240 Speaker 1: go superno, but we don't know which white dwarfs are 526 00:27:15,240 --> 00:27:18,680 Speaker 1: about to go. So we really haven't seen the very 527 00:27:18,720 --> 00:27:22,480 Speaker 1: beginning moments very often, and so it's really difficult to 528 00:27:22,520 --> 00:27:27,199 Speaker 1: study until compare our simulations to data because it happens 529 00:27:27,200 --> 00:27:30,040 Speaker 1: within a few seconds. Like it's like it would like 530 00:27:30,080 --> 00:27:32,280 Speaker 1: be trying to figure out what made a grenade explode 531 00:27:32,400 --> 00:27:35,199 Speaker 1: or something, because you know, it just explodes. Yeah, it's 532 00:27:35,240 --> 00:27:37,520 Speaker 1: like if you're looking at a huge field of grenades 533 00:27:37,840 --> 00:27:39,960 Speaker 1: and you don't know which one is going to explode. 534 00:27:40,040 --> 00:27:41,720 Speaker 1: All you can do is like snap your neck around 535 00:27:41,720 --> 00:27:43,600 Speaker 1: as soon as one blows, But then you've missed it. 536 00:27:43,840 --> 00:27:46,240 Speaker 1: So you never get to see those first moments. And 537 00:27:46,280 --> 00:27:48,360 Speaker 1: so you might think, well, why don't we just image 538 00:27:48,400 --> 00:27:51,040 Speaker 1: all the stars all the time, And yeah, I'd love 539 00:27:51,080 --> 00:27:53,320 Speaker 1: to do that, right, that would be a great strategy. 540 00:27:53,520 --> 00:27:55,800 Speaker 1: Just as just as signed some grad students to each 541 00:27:55,800 --> 00:27:58,520 Speaker 1: star in the in the universe, how many grad students 542 00:27:58,520 --> 00:28:00,520 Speaker 1: do we have, and we do have have some really 543 00:28:00,520 --> 00:28:04,199 Speaker 1: big survey missions UM that scanned the whole sky and 544 00:28:04,240 --> 00:28:06,640 Speaker 1: try to spot these things. But again, you can only 545 00:28:06,680 --> 00:28:08,800 Speaker 1: notice them, you know, after they happen. We'd love to 546 00:28:08,840 --> 00:28:11,639 Speaker 1: study them just before they happen, so we can see 547 00:28:12,200 --> 00:28:15,960 Speaker 1: what's causing it, right, because I guess we UM. I mean, 548 00:28:16,080 --> 00:28:18,200 Speaker 1: they do surveys of the sky that they're always looking 549 00:28:18,200 --> 00:28:21,239 Speaker 1: at stars, but to get enough of information from the 550 00:28:21,280 --> 00:28:23,080 Speaker 1: one that blew up is hard because you have to 551 00:28:23,080 --> 00:28:25,960 Speaker 1: sort of focus on it. Yeah, and you'd love to 552 00:28:26,080 --> 00:28:28,200 Speaker 1: use our most powerful telescopes. And we have sort of 553 00:28:28,240 --> 00:28:30,879 Speaker 1: two kinds of telescopes. Ones that are really broad they 554 00:28:30,880 --> 00:28:34,040 Speaker 1: can image the whole night sky, but they're not that powerful, 555 00:28:34,400 --> 00:28:37,320 Speaker 1: and ones that can look really deeply at one object, 556 00:28:37,359 --> 00:28:40,640 Speaker 1: like the hubble, you know, but it can't really scan 557 00:28:40,720 --> 00:28:42,880 Speaker 1: the whole night sky because it's it has to point 558 00:28:42,920 --> 00:28:45,680 Speaker 1: really carefully at one thing. I see. So even with 559 00:28:45,720 --> 00:28:48,480 Speaker 1: the early warning system of the neutrinos, we can't that 560 00:28:48,640 --> 00:28:51,160 Speaker 1: won't tell us which star is gonna blow. That's what 561 00:28:51,200 --> 00:28:53,600 Speaker 1: we try to do. We try to see the neutrinos 562 00:28:53,680 --> 00:28:55,960 Speaker 1: and then like whip stuff around. But you know, neutrinos 563 00:28:55,960 --> 00:28:58,720 Speaker 1: are hard to spot because even a gazillion of them 564 00:28:58,920 --> 00:29:01,560 Speaker 1: will come through the Earth and not interact. And you know, 565 00:29:01,640 --> 00:29:04,120 Speaker 1: new tunion detectors are sometimes busy doing other things, are 566 00:29:04,160 --> 00:29:07,920 Speaker 1: not dedicated to supernova's. They try to hook these things up, 567 00:29:07,960 --> 00:29:10,000 Speaker 1: and when the neutrinos tell us the superno is coming, 568 00:29:10,000 --> 00:29:12,600 Speaker 1: they point in that direction. And so we do our best, 569 00:29:12,600 --> 00:29:15,760 Speaker 1: because remember, the supernovas have taught us a lot about 570 00:29:15,800 --> 00:29:17,640 Speaker 1: the universe. They're the ones that gave us the clue 571 00:29:17,680 --> 00:29:20,240 Speaker 1: that the universe is expanding. All right, So that that's 572 00:29:20,280 --> 00:29:23,680 Speaker 1: the first way that a star can goes supernova is 573 00:29:23,720 --> 00:29:26,840 Speaker 1: it's happily retired, but then it gets something triggers it, 574 00:29:27,000 --> 00:29:30,000 Speaker 1: and it just goes out in a blaze of glory, 575 00:29:31,320 --> 00:29:34,160 Speaker 1: runaway blaze of glory. That's right. It was saving up 576 00:29:34,160 --> 00:29:36,200 Speaker 1: for one last hurrah. All right, Let's get into the 577 00:29:36,240 --> 00:29:39,280 Speaker 1: second way in which supernose can happen, But first let's 578 00:29:39,280 --> 00:29:54,160 Speaker 1: take a quick break, al right, Daniel. So the second 579 00:29:54,200 --> 00:29:58,080 Speaker 1: way that uh supernova can happen is called core collapse. 580 00:29:58,160 --> 00:29:59,760 Speaker 1: And I think this is maybe the one that most 581 00:29:59,760 --> 00:30:02,160 Speaker 1: peop we're familiar with. Why why is this one? More? 582 00:30:02,440 --> 00:30:05,720 Speaker 1: I guess popular this is the case where gravity wins 583 00:30:05,760 --> 00:30:08,760 Speaker 1: in the epics struggle with fusion. I think this one's 584 00:30:08,800 --> 00:30:11,720 Speaker 1: maybe more awesome. I mean, I don't mean anything negative 585 00:30:11,800 --> 00:30:15,080 Speaker 1: about runaway fusion the size of a star glowing five 586 00:30:15,120 --> 00:30:18,000 Speaker 1: billion times brighter than the sun. But this one involves 587 00:30:18,120 --> 00:30:22,320 Speaker 1: implosion and explosion, so maybe it's like double awesome. Okay, 588 00:30:22,360 --> 00:30:24,880 Speaker 1: so there's some implosion involved in this one, right, I 589 00:30:24,880 --> 00:30:28,239 Speaker 1: guess it's in the word core collapse. Yeah. So in 590 00:30:28,280 --> 00:30:31,000 Speaker 1: this scenario, again, you start as a really big star. 591 00:30:31,040 --> 00:30:33,600 Speaker 1: You've gotta be our big enough star to even consider 592 00:30:33,720 --> 00:30:36,680 Speaker 1: going supernova, like a star like our Sun is never 593 00:30:36,680 --> 00:30:40,400 Speaker 1: going to go supernova. Hey, that's good to know, and 594 00:30:40,440 --> 00:30:42,560 Speaker 1: be what do you mean big? Like, what's the threshold 595 00:30:42,560 --> 00:30:45,040 Speaker 1: for supernova? Is it like many times the size of 596 00:30:45,080 --> 00:30:47,280 Speaker 1: our sun or a little bit more. It's like five 597 00:30:47,320 --> 00:30:49,000 Speaker 1: to eight times in the mass of the Sun is 598 00:30:49,160 --> 00:30:52,160 Speaker 1: like the bare minimum you need to have a supernova. 599 00:30:52,280 --> 00:30:54,440 Speaker 1: Beyond that, you can't even get an agent to return 600 00:30:54,480 --> 00:30:59,200 Speaker 1: your phone. Yeah, you're forever be list which I think 601 00:30:59,280 --> 00:31:02,400 Speaker 1: is a good thing. But this sort of core collapse 602 00:31:02,400 --> 00:31:05,640 Speaker 1: superno requires a really big star. And we were talking 603 00:31:05,680 --> 00:31:07,920 Speaker 1: earlier about what's happening inside the stars. You have this 604 00:31:08,000 --> 00:31:11,320 Speaker 1: fusion and you're creating heavier and heavier stuff. Well, in 605 00:31:11,360 --> 00:31:14,480 Speaker 1: some stars they are big enough to fuse carbon, and 606 00:31:14,520 --> 00:31:17,480 Speaker 1: then they fuse the byproducts of carbon and make heavier stuff, 607 00:31:17,480 --> 00:31:20,360 Speaker 1: and the byproduct of that make even heavier stuff. So 608 00:31:20,360 --> 00:31:23,040 Speaker 1: it's a bigger factory, and it goes beyond what these 609 00:31:23,080 --> 00:31:25,680 Speaker 1: other stars that we talked about can do. They can 610 00:31:25,720 --> 00:31:29,760 Speaker 1: actually fuse carbon and and uh and make heavier and 611 00:31:29,760 --> 00:31:32,600 Speaker 1: heavier elements. But it's sort of a more controlled process 612 00:31:32,600 --> 00:31:35,160 Speaker 1: because it's happening gradually. It's like an equilibrium. Stuff is 613 00:31:35,200 --> 00:31:38,360 Speaker 1: slashing back and forth, and the carbon fuses and turns 614 00:31:38,360 --> 00:31:41,480 Speaker 1: into the next thing. And these guys confuse all the 615 00:31:41,480 --> 00:31:43,960 Speaker 1: way up to iron. Remember that up to iron, when 616 00:31:43,960 --> 00:31:47,760 Speaker 1: you have fusion, you release energy. Above iron or nickel 617 00:31:47,880 --> 00:31:51,240 Speaker 1: or so when you fuse it absorbs energy and so 618 00:31:51,280 --> 00:31:53,920 Speaker 1: it would cool the star down. So like what comes 619 00:31:54,080 --> 00:31:57,360 Speaker 1: right before iron. Yes, so iron is number twenty six 620 00:31:57,440 --> 00:31:59,920 Speaker 1: and nicholas, and that's about as high as you can go. 621 00:32:00,160 --> 00:32:03,640 Speaker 1: I mean below that you have oxygen at eight you 622 00:32:03,640 --> 00:32:09,320 Speaker 1: can make you make magnesium a twelve aluminum silicon. Anything 623 00:32:09,360 --> 00:32:13,560 Speaker 1: below iron, when you fuse it together, releases energy so 624 00:32:13,600 --> 00:32:18,080 Speaker 1: that that sustains the explosion of the star. But you're saying, 625 00:32:18,520 --> 00:32:20,640 Speaker 1: after iron, if I want to fuse more things, I 626 00:32:20,680 --> 00:32:23,080 Speaker 1: have to sink energy into it. Yeah, and so it 627 00:32:23,080 --> 00:32:25,360 Speaker 1: actually sucks energy out of the star. It starts to 628 00:32:25,400 --> 00:32:27,880 Speaker 1: cool it. And this is the enemy of the star. 629 00:32:28,200 --> 00:32:31,280 Speaker 1: The star remembers trying to well, it doesn't like feel 630 00:32:31,320 --> 00:32:33,560 Speaker 1: anything or want anything. But if a star is going 631 00:32:33,600 --> 00:32:36,200 Speaker 1: to continue to burn, it needs to exert outward pressure 632 00:32:36,240 --> 00:32:39,760 Speaker 1: against gravity. But it's sort of working against itself because 633 00:32:39,800 --> 00:32:42,719 Speaker 1: it's making heavier and heavier stuffed. And so you know, 634 00:32:42,840 --> 00:32:46,240 Speaker 1: as it's making heavier and heavier stuff, it's making the 635 00:32:46,280 --> 00:32:49,920 Speaker 1: gravity stronger and more powerful because it's getting denser at 636 00:32:49,960 --> 00:32:53,920 Speaker 1: its core. And so if you're then also cooling down 637 00:32:54,000 --> 00:32:58,560 Speaker 1: your own reaction, then you're fighting against yourself. Wow. So 638 00:32:58,640 --> 00:33:01,560 Speaker 1: and eventually what happens. It winds like you run out 639 00:33:01,600 --> 00:33:05,680 Speaker 1: of things to fuse. Everything's iron, and then gravity wins. Yeah, 640 00:33:05,720 --> 00:33:10,160 Speaker 1: eventually gravity wins and it pulls itself together and it 641 00:33:10,280 --> 00:33:13,680 Speaker 1: collapses and gravity says, all right, I'm blowing past you. 642 00:33:14,040 --> 00:33:16,840 Speaker 1: And there's this point it's called the Chandra Shaker limit. 643 00:33:17,080 --> 00:33:21,200 Speaker 1: It's essentially when matter cannot be squeezed anymore. Let's see 644 00:33:21,200 --> 00:33:25,080 Speaker 1: when all the electrons are pushed down into their lowest orbitals, 645 00:33:25,240 --> 00:33:28,480 Speaker 1: and everything is tucked as close as possible, and that's 646 00:33:28,520 --> 00:33:30,600 Speaker 1: what like a white dwarf for a neutron star is 647 00:33:30,600 --> 00:33:34,880 Speaker 1: sitting at. But when gravity has enough power to overcome that, 648 00:33:34,880 --> 00:33:37,720 Speaker 1: that electron degenerously. When you have too much stuff, then 649 00:33:37,760 --> 00:33:41,200 Speaker 1: it collapses and gravity takes over, meaning that um, whatever 650 00:33:41,320 --> 00:33:46,480 Speaker 1: is keeping the star kind of fluffy, it's no longer enough. 651 00:33:46,640 --> 00:33:49,320 Speaker 1: Burned too much, and now it's it's too heavy. Yeah, 652 00:33:49,480 --> 00:33:53,880 Speaker 1: there's not enough outwards pressure and there's growing gravitational pressure inwards, 653 00:33:54,240 --> 00:33:57,040 Speaker 1: and so eventually gravity just overwhelms it, and that's when 654 00:33:57,080 --> 00:33:59,760 Speaker 1: you get this core collapse. I guess collapse means that 655 00:33:59,800 --> 00:34:03,640 Speaker 1: it it's just sort of like folds folds in or 656 00:34:03,720 --> 00:34:06,080 Speaker 1: what does that mean? Like all the Adams were happy 657 00:34:06,120 --> 00:34:09,440 Speaker 1: sort of bunched together, but now they crunched in together more. Yeah, 658 00:34:09,480 --> 00:34:12,120 Speaker 1: and you actually get an inwards going shock wave. And 659 00:34:12,160 --> 00:34:16,560 Speaker 1: so people sometimes talk about supernovas as implosions and that's why, 660 00:34:16,640 --> 00:34:19,600 Speaker 1: because you get this shock wave of stuff rushing in 661 00:34:19,760 --> 00:34:23,680 Speaker 1: towards the center. Wow, because the in the innerts of 662 00:34:23,760 --> 00:34:27,879 Speaker 1: the star are I guess collapsing before they were sort 663 00:34:27,880 --> 00:34:30,279 Speaker 1: of fluffy from all the energy. But now they're just 664 00:34:30,560 --> 00:34:33,240 Speaker 1: they're out of energy, so that everything's just crunching together. 665 00:34:33,680 --> 00:34:36,040 Speaker 1: To think about the surface of the star, what's happening 666 00:34:36,080 --> 00:34:38,920 Speaker 1: there is it's constantly getting pulled in by all the 667 00:34:38,960 --> 00:34:41,799 Speaker 1: heavy stuff inside the star, and it's getting pushed out 668 00:34:41,840 --> 00:34:45,399 Speaker 1: by the burning. Eventually, if the burning is not strong enough, 669 00:34:45,400 --> 00:34:47,800 Speaker 1: you know, if it passes this limit, then that stuff 670 00:34:47,920 --> 00:34:50,399 Speaker 1: gets pulled in and it compresses the next layer, which 671 00:34:50,400 --> 00:34:52,719 Speaker 1: compresses the next layer, which compresses the next layer. And 672 00:34:52,719 --> 00:34:55,360 Speaker 1: it's a runaway process because the more you compress something, 673 00:34:55,560 --> 00:35:00,200 Speaker 1: the higher density it is, the stronger the gravitational force, right, 674 00:35:00,200 --> 00:35:04,759 Speaker 1: because as you get closer, the gravity stronger. Yeah, so 675 00:35:04,960 --> 00:35:08,120 Speaker 1: the whole thing just it just falls inwards. It falls inwards, 676 00:35:08,160 --> 00:35:11,080 Speaker 1: and then what happens depends on how much stuff you 677 00:35:11,160 --> 00:35:14,160 Speaker 1: started with. And if you're like super duper big, like 678 00:35:14,320 --> 00:35:17,000 Speaker 1: more than forty times the mass of our Sun, then 679 00:35:17,040 --> 00:35:19,479 Speaker 1: that's basically it. You just collapse into a black hole 680 00:35:19,640 --> 00:35:22,160 Speaker 1: without even making a peep. The star just kind of 681 00:35:22,560 --> 00:35:24,440 Speaker 1: bloop turns into a black hole. Yeah, you can just 682 00:35:24,440 --> 00:35:28,440 Speaker 1: go and suck itself into a black hole without a supernova, 683 00:35:28,520 --> 00:35:31,600 Speaker 1: like you can skip the supernova stuff. If you're big, Okay, 684 00:35:31,880 --> 00:35:34,400 Speaker 1: so that's if you're really big. If you're really big, 685 00:35:34,640 --> 00:35:37,200 Speaker 1: But if you're not big enough, then the core collapse 686 00:35:37,239 --> 00:35:40,920 Speaker 1: sort of goes inwards and then it bounces off the hot, 687 00:35:40,960 --> 00:35:43,799 Speaker 1: dense core of the start, like the shock wave comes 688 00:35:43,840 --> 00:35:46,040 Speaker 1: in and it reaches a point where the stuff is 689 00:35:46,080 --> 00:35:49,520 Speaker 1: so dense that it can reflect that shock wave back out, 690 00:35:50,080 --> 00:35:52,880 Speaker 1: and that's when the supernova happens. That's when like stuff 691 00:35:52,960 --> 00:35:56,440 Speaker 1: flies out from the star. Oh, it's all this energy 692 00:35:56,440 --> 00:36:00,560 Speaker 1: of stuff falling in. It's the balance. That's actually the explode. Yes, 693 00:36:00,600 --> 00:36:02,879 Speaker 1: it's the bounce. And if you're too big, you don't 694 00:36:02,920 --> 00:36:05,399 Speaker 1: get the bounce, right because it just like turns into 695 00:36:05,440 --> 00:36:07,680 Speaker 1: a black hole and then nothing can escape. But if 696 00:36:07,719 --> 00:36:10,600 Speaker 1: you're if you're below that, if you're like around thirty 697 00:36:11,239 --> 00:36:13,520 Speaker 1: times the mass of the Sun, then you get a 698 00:36:13,520 --> 00:36:16,040 Speaker 1: bounce that goes out with a supernova and the core 699 00:36:16,160 --> 00:36:19,520 Speaker 1: becomes a black hole. Oh really, only the core that 700 00:36:19,600 --> 00:36:22,759 Speaker 1: the other stuff bounces away. Yeah, you get the supernova, 701 00:36:22,800 --> 00:36:26,320 Speaker 1: this huge shock you know, expus plasma through the universe 702 00:36:26,320 --> 00:36:29,279 Speaker 1: and neutrinos and light and energy, but the core of 703 00:36:29,320 --> 00:36:31,960 Speaker 1: it remains and becomes a black hole, and that's different 704 00:36:31,960 --> 00:36:34,600 Speaker 1: than the other kind of runaway fusion, which didn't form 705 00:36:34,640 --> 00:36:36,680 Speaker 1: a black hole. That's right, Those don't usually form a 706 00:36:36,680 --> 00:36:39,720 Speaker 1: black hole. Sometimes those can end with a really dense 707 00:36:39,760 --> 00:36:42,080 Speaker 1: neutron star, but a lot of times it's just blowing 708 00:36:42,120 --> 00:36:44,200 Speaker 1: out most of the mass of the star in the 709 00:36:44,280 --> 00:36:47,840 Speaker 1: runaway fusion. In this case, if you're more than forty 710 00:36:47,840 --> 00:36:49,600 Speaker 1: times the mass of the Sun, you go straight to 711 00:36:49,680 --> 00:36:52,399 Speaker 1: black hole. If you're more than thirty times the mass 712 00:36:52,400 --> 00:36:54,680 Speaker 1: of the Sun, you've got a huge supernova when the 713 00:36:54,719 --> 00:36:57,320 Speaker 1: bounce turns around and you get a black hole the core. 714 00:36:58,040 --> 00:37:00,600 Speaker 1: If you're a little smaller than that, it's the same story. 715 00:37:01,080 --> 00:37:04,319 Speaker 1: Things bounce off the center and then explode down to 716 00:37:04,360 --> 00:37:06,719 Speaker 1: a supernova, but instead of a black hole the center, 717 00:37:06,719 --> 00:37:09,080 Speaker 1: and you get a neutron star, which is like a 718 00:37:09,280 --> 00:37:12,759 Speaker 1: really dense massive material, but not quite dense enough to 719 00:37:12,800 --> 00:37:15,680 Speaker 1: form a black hole. I see you just you just 720 00:37:15,760 --> 00:37:18,680 Speaker 1: become a like a compact star. Yes, you just become 721 00:37:18,719 --> 00:37:21,880 Speaker 1: a really compact blob. And then there's a little window 722 00:37:22,200 --> 00:37:24,879 Speaker 1: between like seven and ten times the mass of our 723 00:37:24,960 --> 00:37:29,279 Speaker 1: Sun where um when the gravitational collapse happens. Then it 724 00:37:29,400 --> 00:37:33,440 Speaker 1: causes runaway fusion and the whole thing just blows um 725 00:37:33,480 --> 00:37:36,880 Speaker 1: in a huge explosion. So there's all these like pockets 726 00:37:36,920 --> 00:37:39,640 Speaker 1: like if you're this big, then you'll go supernova if 727 00:37:39,640 --> 00:37:41,640 Speaker 1: you but if you're a little bit smaller you won't. 728 00:37:41,640 --> 00:37:43,879 Speaker 1: But then if you're a little bit smaller still you will. 729 00:37:44,040 --> 00:37:46,120 Speaker 1: Like we said, the fate of the star depends almost 730 00:37:46,200 --> 00:37:49,400 Speaker 1: entirely on its mass, and so there these little windows 731 00:37:49,440 --> 00:37:51,120 Speaker 1: like if you're in this window, this happens. If you're 732 00:37:51,120 --> 00:37:53,040 Speaker 1: in this window, that happens. It's like, oh, man, I 733 00:37:53,040 --> 00:37:56,120 Speaker 1: shouldn't have eaten that last planet now, now now I'm 734 00:37:56,160 --> 00:38:01,520 Speaker 1: gonna explode. Literally. Wow, that's interesting. But again, sort of 735 00:38:01,520 --> 00:38:04,640 Speaker 1: the common thing about all of these scenarios is that 736 00:38:05,040 --> 00:38:09,160 Speaker 1: it's the it's a collapsing star that becomes a supernova, right, 737 00:38:09,640 --> 00:38:11,799 Speaker 1: And sometimes it's at the bound. Sometimes it's just it 738 00:38:11,840 --> 00:38:15,960 Speaker 1: creates a runaway explosion. Yea. For all these core collapse 739 00:38:15,960 --> 00:38:18,799 Speaker 1: they start with really big stars have been big enough 740 00:38:18,960 --> 00:38:21,040 Speaker 1: to burn a lot of heavy stuff to go past 741 00:38:21,080 --> 00:38:23,920 Speaker 1: the carbon limit and uh, and then to pass this 742 00:38:24,000 --> 00:38:28,799 Speaker 1: gender's say, card limit and collapse gravitationally, right, and then 743 00:38:29,000 --> 00:38:31,960 Speaker 1: a couple of different things might happen after that. To 744 00:38:32,040 --> 00:38:35,560 Speaker 1: be a supernova or not. Yeah, you could be black hole. 745 00:38:35,680 --> 00:38:38,040 Speaker 1: You can be black hole plus supernova. You can be 746 00:38:38,120 --> 00:38:40,799 Speaker 1: just supernova. You could have as a neutron star. There's 747 00:38:40,880 --> 00:38:42,719 Speaker 1: lots of different options there, all right, So I guess 748 00:38:42,719 --> 00:38:45,880 Speaker 1: the next question is should we worry about supernova? Is Daniel, 749 00:38:45,960 --> 00:38:49,040 Speaker 1: is this something that might happen like with three minute warning, 750 00:38:49,320 --> 00:38:51,000 Speaker 1: we'll find out that the star next to us is 751 00:38:51,000 --> 00:38:55,200 Speaker 1: going supernova and then and then goodbye Planet Earth? Or 752 00:38:55,320 --> 00:38:57,839 Speaker 1: is it unlikely to happen around us? Well, we sort 753 00:38:57,840 --> 00:39:00,480 Speaker 1: of trying to calculate two different things. One is how 754 00:39:00,520 --> 00:39:03,640 Speaker 1: close would a supernova have to be to be dangerous? 755 00:39:04,239 --> 00:39:07,120 Speaker 1: And they figured that if ones within like twenty five 756 00:39:07,239 --> 00:39:09,840 Speaker 1: light years or so, it would basically destroy half of 757 00:39:09,880 --> 00:39:12,480 Speaker 1: the Earth's ozone layer, because the half that's facing that 758 00:39:12,560 --> 00:39:15,040 Speaker 1: star would be fried. And that would be bad because 759 00:39:15,080 --> 00:39:17,800 Speaker 1: we'd be suddenly like totally exposed to space. An amount 760 00:39:17,840 --> 00:39:20,399 Speaker 1: of X rays deposited on the planet would like sterilize 761 00:39:20,400 --> 00:39:23,799 Speaker 1: half the population and or give them cancer instant, Oh 762 00:39:23,840 --> 00:39:27,839 Speaker 1: my god, within minutes or within days or very quickly. Yeah, 763 00:39:27,920 --> 00:39:29,480 Speaker 1: I mean, does it really matter if it takes days 764 00:39:29,560 --> 00:39:32,239 Speaker 1: or minutes to get cancer? You've got cancer. Well, but 765 00:39:32,400 --> 00:39:34,520 Speaker 1: everything else would stay the same, like a solar system 766 00:39:34,520 --> 00:39:36,160 Speaker 1: would still be here and we'd be going around the 767 00:39:36,160 --> 00:39:38,760 Speaker 1: same orbit. Yeah, and you know, that's an interesting question. 768 00:39:38,840 --> 00:39:42,360 Speaker 1: People wonder if there are gravitational waves from supernova, but 769 00:39:42,440 --> 00:39:45,000 Speaker 1: we've never seen one before. But it wouldn't affect like 770 00:39:45,000 --> 00:39:47,040 Speaker 1: the gravity of the Earth. We'd still be orbiting the 771 00:39:47,040 --> 00:39:48,799 Speaker 1: Sun the same way. Would just be like you know, 772 00:39:48,960 --> 00:39:52,480 Speaker 1: mostly toast. But fortunately, we've looked around and we haven't 773 00:39:52,480 --> 00:39:55,120 Speaker 1: spotted anything that we think is going to go supernova, 774 00:39:55,160 --> 00:39:59,120 Speaker 1: anything anywhere within the nearest five light years. Now, again, 775 00:39:59,400 --> 00:40:02,600 Speaker 1: we don't have a great understanding of when a stargo supernova, 776 00:40:02,800 --> 00:40:04,680 Speaker 1: but we think we have a sense for the which 777 00:40:04,800 --> 00:40:07,480 Speaker 1: kind of star can go supernova, and we don't see 778 00:40:07,480 --> 00:40:10,279 Speaker 1: any of those nearby. And you know, supernovas are not 779 00:40:10,400 --> 00:40:13,520 Speaker 1: just bad news, right, supernova is they're sort of part 780 00:40:13,560 --> 00:40:16,359 Speaker 1: of the life cycle of the galaxy. You know how 781 00:40:16,360 --> 00:40:19,040 Speaker 1: we learned that forest fires aren't all bad because they 782 00:40:19,040 --> 00:40:22,360 Speaker 1: helped like clean out dead wood and provide space for 783 00:40:22,440 --> 00:40:25,239 Speaker 1: new animals. You know, well, they're good as long as 784 00:40:25,239 --> 00:40:28,200 Speaker 1: you don't live in your house is not next to you. Yeah, 785 00:40:28,239 --> 00:40:31,080 Speaker 1: exactly that way. It's a sign of a healthy forest 786 00:40:31,120 --> 00:40:34,040 Speaker 1: to have occasional small fires. In the same way it's 787 00:40:34,040 --> 00:40:37,200 Speaker 1: a sign of a healthy galaxy to occasionally, know, clear 788 00:40:37,200 --> 00:40:39,200 Speaker 1: out some of the clutter in the dust and blow 789 00:40:39,239 --> 00:40:41,160 Speaker 1: up the old stuff and make room for something new. 790 00:40:41,280 --> 00:40:44,799 Speaker 1: Because that is kind of how um heavier materials like 791 00:40:44,880 --> 00:40:47,400 Speaker 1: we wouldn't be you and I wouldn't be here if 792 00:40:47,480 --> 00:40:50,719 Speaker 1: if it's not for a supernova, and it's not just 793 00:40:50,840 --> 00:40:53,440 Speaker 1: the supernova throw that stuff out into the universe. That 794 00:40:53,600 --> 00:40:56,720 Speaker 1: is true. But also we wonder about like what makes 795 00:40:56,719 --> 00:40:59,320 Speaker 1: a star begin, Like give a big cloud of gas 796 00:40:59,360 --> 00:41:02,480 Speaker 1: and dust. Is gravity just like very gradually pulling it 797 00:41:02,560 --> 00:41:05,279 Speaker 1: together over billions of years. Some people think that it's 798 00:41:05,320 --> 00:41:08,120 Speaker 1: the shock wave from a nearby supernova that sort of 799 00:41:08,200 --> 00:41:12,640 Speaker 1: triggers that gravitational collapse of that cloud into a star. 800 00:41:13,080 --> 00:41:15,319 Speaker 1: So it might be that the death of a star 801 00:41:15,440 --> 00:41:18,600 Speaker 1: the supernova is what you need to form new stars. 802 00:41:18,920 --> 00:41:22,440 Speaker 1: Stars begetting stars. It's all cycle, man, it's the circle 803 00:41:22,480 --> 00:41:26,200 Speaker 1: of life. Somebody que Elton John, But who who made 804 00:41:26,200 --> 00:41:28,120 Speaker 1: the first star? Then, Daniel, what came for as the 805 00:41:28,160 --> 00:41:32,360 Speaker 1: star or the supernova? The eternal question? I believe that 806 00:41:32,400 --> 00:41:34,800 Speaker 1: one for the philosopher's all right, well, I feel like 807 00:41:34,800 --> 00:41:37,320 Speaker 1: I learned a lot about supernovas today. You know, I 808 00:41:37,800 --> 00:41:41,200 Speaker 1: thought that they only did the supernova through core collapse. 809 00:41:41,200 --> 00:41:43,200 Speaker 1: They didn't know that there were all these other ways 810 00:41:43,239 --> 00:41:46,600 Speaker 1: that they can happen. Yeah, supernovura fascinating and we're constantly 811 00:41:46,600 --> 00:41:49,000 Speaker 1: studying them because they are dramatic and they're awesome to 812 00:41:49,080 --> 00:41:51,480 Speaker 1: learn about, and because we'd like to know, you know, 813 00:41:51,680 --> 00:41:53,399 Speaker 1: what happens at the end of life of a star. 814 00:41:53,480 --> 00:41:57,839 Speaker 1: It's it's fascinating, it's dramatic, but it's also still mysterious. Yeah, 815 00:41:57,880 --> 00:42:00,719 Speaker 1: and it's a big part of how the universe works, right, 816 00:42:00,960 --> 00:42:05,080 Speaker 1: like how you make metals and everything all around this, 817 00:42:05,760 --> 00:42:08,480 Speaker 1: everything around us is was basically made in a supernova. 818 00:42:08,560 --> 00:42:11,600 Speaker 1: Would you say that, like all the metal and components 819 00:42:11,600 --> 00:42:14,799 Speaker 1: in your phone, in your car, that all came from 820 00:42:14,800 --> 00:42:17,719 Speaker 1: a supernova. All that stuff was fused inside a hot 821 00:42:17,760 --> 00:42:20,719 Speaker 1: star billions of years ago. Yes. All right, Well, we 822 00:42:21,280 --> 00:42:22,960 Speaker 1: hope you enjoyed that. And the next time you look 823 00:42:23,040 --> 00:42:25,040 Speaker 1: up at the night sky and see something getting brighter, 824 00:42:25,320 --> 00:42:29,320 Speaker 1: duck or at least close your eyes. At least close 825 00:42:29,400 --> 00:42:32,799 Speaker 1: your eyes and look it up online later. All right, 826 00:42:32,840 --> 00:42:43,239 Speaker 1: thanks for joining us, See you next time. Before you 827 00:42:43,320 --> 00:42:46,160 Speaker 1: still have a question after listening to all these explanations, 828 00:42:46,239 --> 00:42:49,200 Speaker 1: please drop us a line. We'd love to hear from you. 829 00:42:49,200 --> 00:42:52,000 Speaker 1: You can find us on Facebook, Twitter, and Instagram at 830 00:42:52,360 --> 00:42:55,520 Speaker 1: Daniel and Jorge That's one Word, or email us at 831 00:42:55,800 --> 00:42:59,480 Speaker 1: Feedback at Daniel and Jorge dot com. Thanks for listening, 832 00:42:59,480 --> 00:43:02,200 Speaker 1: and remember that Daniel and Jorge Explain the Universe is 833 00:43:02,239 --> 00:43:05,759 Speaker 1: a production of I Heart Radio. For more podcast from 834 00:43:05,760 --> 00:43:09,560 Speaker 1: my heart Radio, visit the I heart Radio Apple Podcasts, 835 00:43:09,640 --> 00:43:17,360 Speaker 1: or wherever you listen to your favorite shows. Yeah,