WEBVTT - Listener Questions #5 0:00:06.040 --> 0:00:10.080 Are black holes actually black? Is life always built on 0:00:10.119 --> 0:00:11.040 a carbon stack? 0:00:11.280 --> 0:00:14.360 Can one star make another explode? What happens if you 0:00:14.440 --> 0:00:15.600 lick an electrode? 0:00:15.720 --> 0:00:19.200 Would biology beat physics in a fair fight? Why is 0:00:19.280 --> 0:00:20.760 dark chocolate better than white? 0:00:20.960 --> 0:00:25.440 Hawking predicted that black holes glow? What makes a supernova blow? 0:00:25.800 --> 0:00:31.480 Biology, physics, archaeology, forestry, really anything other than chemistry? 0:00:31.640 --> 0:00:34.600 What diseases do you get from your cat? Well, we'll 0:00:34.640 --> 0:00:36.040 find the answers to all that. 0:00:36.600 --> 0:00:39.519 Whatever questions keep you up at night, Daniel and Kelly's 0:00:39.520 --> 0:00:42.920 answer will make it right. Welcome to another Listener Questions 0:00:42.960 --> 0:01:00.640 episode on Daniel and Kelly's Extraordinary Universe. Hello, Kelly Weener 0:01:00.720 --> 0:01:04.600 Spin I'm a parasitologist, and today we're talking about chemistry. 0:01:05.959 --> 0:01:09.240 Hi, I'm Daniel. I'm a particle physicist because I don't 0:01:09.280 --> 0:01:11.600 like chemistry. So what am I even doing here today? 0:01:12.040 --> 0:01:14.520 Well, so, Daniel, my question for you today is why 0:01:14.640 --> 0:01:16.120 is chemistry the worst science? 0:01:17.319 --> 0:01:20.679 How much time do you have, Kelly. 0:01:20.240 --> 0:01:21.560 I've did, We've got an hour. 0:01:22.200 --> 0:01:25.959 No, chemistry is amazing because it's the closest thing we 0:01:26.080 --> 0:01:29.600 have to explaining magic, like the things that you can 0:01:29.640 --> 0:01:33.600 see happen with your own eyes. You know, seeing a 0:01:33.640 --> 0:01:35.800 solid turn into a liquid turn into a gas is 0:01:35.920 --> 0:01:37.800 kind of incredible, and the fact that we can take 0:01:37.840 --> 0:01:41.600 that apart and understand it microscopically is amazing. And it's 0:01:41.600 --> 0:01:45.440 so much more concrete than particle physics or even astrophysics sometimes. 0:01:45.440 --> 0:01:47.480 So I have a lot of respect for the relevance 0:01:47.520 --> 0:01:51.880 of chemistry, but I really struggle with the complexity of it, 0:01:52.040 --> 0:01:54.960 Like there's so many different rules to apply in different 0:01:55.000 --> 0:01:58.240 situations and a weeks to remember all the exceptions, and 0:01:58.280 --> 0:02:01.080 this electron and that electron, and it doesn't have the 0:02:01.120 --> 0:02:04.200 simplicity that I like in particle physics. But you know, hey, 0:02:04.480 --> 0:02:08.040 that's purely a subjective preference, right, And I'm really glad 0:02:08.080 --> 0:02:10.520 that there's different kinds of science for different kinds of folks, 0:02:10.880 --> 0:02:12.800 so we get all the fun different kinds of sciences 0:02:12.800 --> 0:02:14.160 happening here on our planet. 0:02:14.280 --> 0:02:17.040 Yeah, no, I agree, and I'm joking. My senior honors 0:02:17.080 --> 0:02:20.160 research project was in organic chemistry. I'm minored in chemistry, 0:02:20.639 --> 0:02:23.160 but man, it was hard taking oakem over the summer 0:02:23.200 --> 0:02:26.200 because I'm not good at visualizing things in three D 0:02:26.440 --> 0:02:29.160 and seeing those reactions happen in my head is really hard. 0:02:29.520 --> 0:02:31.320 But I got lucky, so I took it over the summer, 0:02:31.360 --> 0:02:33.920 and it was like four hours of lecture and then 0:02:33.960 --> 0:02:36.800 two hours of lab like every day of the week. 0:02:36.840 --> 0:02:39.200 It was intense. I had a group of friends. I 0:02:39.240 --> 0:02:41.760 was one of six, and we called ourselves the Benzene 0:02:41.840 --> 0:02:44.560 Ring because there's six carbons and a benzene ring. 0:02:44.800 --> 0:02:46.200 I got a chemistry joke look at that. 0:02:47.080 --> 0:02:49.720 And we would pull all nighters on Thursday nights to 0:02:49.760 --> 0:02:52.799 study for the Friday exams. And I will always think 0:02:52.800 --> 0:02:54.840 fondly of those people who got me through like the 0:02:54.880 --> 0:02:57.880 hardest summer of my life. But anyway, I like it. 0:02:57.919 --> 0:03:01.040 I just find it way harder than just about anything 0:03:01.040 --> 0:03:03.120 else I have to think of. But you know, I 0:03:03.200 --> 0:03:06.040 take a lot of medications that I'm sure would not 0:03:06.280 --> 0:03:08.800 be around but for the miracle of chemistry. 0:03:08.960 --> 0:03:11.880 Exactly. I'm ever so grateful for chemistry. And though I 0:03:11.880 --> 0:03:14.320 take every opportunity to make fun of chemistry, I also 0:03:14.320 --> 0:03:16.040 want to make sure people out there understand that I 0:03:16.040 --> 0:03:17.680 have a lot of respect for it, of course as 0:03:17.720 --> 0:03:19.720 a science. And I will say that there are a 0:03:19.760 --> 0:03:23.680 few listeners who are chemistry professors who write in and say, 0:03:23.760 --> 0:03:25.600 don't worry keep joking about chemistry. 0:03:25.600 --> 0:03:29.080 It makes me laugh so good. Yes, I joke about 0:03:29.080 --> 0:03:30.959 it the same way I joke about a sibling, where 0:03:31.000 --> 0:03:33.040 it's like you love them, you're picking fun at them. 0:03:33.120 --> 0:03:35.200 If somebody else does it, you get a little defensive. 0:03:35.720 --> 0:03:38.520 But yes, no, I love chemistry. It's just man, My 0:03:38.520 --> 0:03:40.600 brain was not made for chemistry, but I'm so glad 0:03:40.640 --> 0:03:41.840 other people's brains are. 0:03:41.880 --> 0:03:44.800 And chemistry, like all kinds of science, inspire people to 0:03:44.920 --> 0:03:47.440 ask questions, to wonder like how does this work? How 0:03:47.440 --> 0:03:49.640 does this fit together? What are the rules for this? 0:03:50.120 --> 0:03:52.960 And if you have questions about physics, or biology or 0:03:53.000 --> 0:03:56.960 even chemistry, please write to us and ask your questions. 0:03:57.040 --> 0:04:00.120 We would love to dig into it to understand the 0:04:00.160 --> 0:04:03.200 benzene rings and everything else about the universe. 0:04:03.880 --> 0:04:06.280 Well, bring another expert on to explain. 0:04:05.920 --> 0:04:09.280 That, And today on the podcast we'll be doing just that, 0:04:09.480 --> 0:04:12.680 answering questions from listeners. We have a lot of fun questions, 0:04:12.920 --> 0:04:17.080 including questions about chain reactions in space, which is sort 0:04:17.080 --> 0:04:21.000 of like superspace chemistry, a question about the chemistry of life, 0:04:21.240 --> 0:04:23.560 and a question about what it all means and how 0:04:23.600 --> 0:04:26.040 we know when to accept a scientific theory. 0:04:26.320 --> 0:04:29.799 An amazing set of questions. Let's get started by hearing 0:04:29.880 --> 0:04:31.159 what Tim wanted to know about. 0:04:32.000 --> 0:04:35.760 I was just listening to your podcast about the brightest 0:04:35.760 --> 0:04:40.080 thing ever seen in the universe, and it got me thinking, 0:04:40.880 --> 0:04:44.240 is there's such a thing as an event where maybe 0:04:45.360 --> 0:04:50.160 a chain reaction explosion in space? Maybe it's a binary 0:04:50.320 --> 0:04:55.200 system supernova, would the other stargo nova as well? Or 0:04:56.360 --> 0:04:59.320 instead of maybe just disintegrating planets, is it possible for 0:04:59.400 --> 0:05:00.960 like the core of a planet to heat up so 0:05:01.000 --> 0:05:04.840 that it explodes. Just piqued by curiosity and thought I'd 0:05:04.839 --> 0:05:05.440 ask the question. 0:05:05.600 --> 0:05:08.479 Thanks, WHOA all right? So I could imagine like looking 0:05:08.480 --> 0:05:11.480 out at the stars at night and seeing like things 0:05:11.520 --> 0:05:14.240 starting to explode in a chain reaction, and being like 0:05:14.720 --> 0:05:16.400 I should have put my kids to bed before this 0:05:16.480 --> 0:05:18.560 happened so they couldn't see it. 0:05:18.760 --> 0:05:18.960 Yeah. 0:05:18.960 --> 0:05:21.120 I was wondering what inspired this question. Maybe Tim was 0:05:21.160 --> 0:05:24.400 worried that, like, if something goes wrong in one star 0:05:24.600 --> 0:05:27.360 and ends cataclysmically, if you could set off a chain 0:05:27.400 --> 0:05:30.400 reaction that like destroys the whole universe or something, or 0:05:30.480 --> 0:05:32.640 if we're safe because every star is so far from 0:05:32.640 --> 0:05:35.280 the other stars that their fates are all independent. 0:05:35.640 --> 0:05:37.120 Sounds like Tim and I would have a good time 0:05:37.200 --> 0:05:39.160 catastrophizing together out of Friday Night. 0:05:40.320 --> 0:05:42.200 But it's a great question because it makes us think 0:05:42.200 --> 0:05:45.000 about the relationship between one star and another and also 0:05:45.080 --> 0:05:48.240 what it takes to like send a star to explode 0:05:48.320 --> 0:05:50.720 or to disintegrate a planet. It is a fun question. 0:05:50.839 --> 0:05:53.320 It sort of thinks about the whole universe as if 0:05:53.360 --> 0:05:55.080 there were elements of a chemical reaction. 0:05:55.279 --> 0:05:58.120 Right, that's true. But let's start with what's happening inside 0:05:58.120 --> 0:06:00.799 of one star, and then we'll scale up to multiple stars. 0:06:01.200 --> 0:06:04.599 You do have chain reactions happening in each star, right, 0:06:04.720 --> 0:06:05.160 that's right. 0:06:05.240 --> 0:06:08.479 Yeah, And a chain reaction essentially is a reaction which 0:06:08.520 --> 0:06:11.560 sets the stage for itself, you know, which makes it 0:06:11.600 --> 0:06:13.960 more likely for it to happen. And so like a 0:06:14.000 --> 0:06:17.480 fire is a chain reaction because the combustion produces heat, 0:06:17.680 --> 0:06:21.400 and that heat triggers more combustion, and so there's a 0:06:21.440 --> 0:06:25.000 loop there, right, or a chain where one's link leads 0:06:25.000 --> 0:06:27.200 to the next link. And as you say, inside a 0:06:27.240 --> 0:06:29.640 star is a sort of a chain reaction because we 0:06:29.640 --> 0:06:33.360 have fusion happening inside a star. You have gravity squeezing 0:06:33.400 --> 0:06:35.839 this hot ball of hydrogen and maybe a little bit 0:06:35.880 --> 0:06:39.960 of helium together, and it creates the conditions necessary for fusion, 0:06:40.279 --> 0:06:44.039 heat and density, and then fusion itself produces more heat 0:06:44.320 --> 0:06:47.400 and that increases the chances of fusion. The odds of 0:06:47.440 --> 0:06:50.520 getting fusion grow very steeply with temperature. So the hotter 0:06:50.640 --> 0:06:53.760 it is, you mean, the faster those particles are whizzing around, 0:06:54.160 --> 0:06:56.440 the more likely you are to have fusion. So heat 0:06:56.600 --> 0:06:58.000 makes fusion more possible. 0:06:58.279 --> 0:07:00.120 Now we have to get to the really exciting part, 0:07:00.160 --> 0:07:03.880 which is the explosions are explosions the results of all 0:07:03.920 --> 0:07:07.200 of the fusion getting out of control. No, when do 0:07:07.240 --> 0:07:08.279 we get the explosions? 0:07:08.400 --> 0:07:08.640 Yeah? 0:07:08.760 --> 0:07:11.920 Essentially you can think of a star during its normal lifetime, 0:07:12.000 --> 0:07:14.760 during the millions or billions of years that it's burning 0:07:14.800 --> 0:07:18.200 stably before it explodes, as in something of a balance. 0:07:18.320 --> 0:07:18.480 Right. 0:07:18.480 --> 0:07:21.880 You have gravity squeezing in, right, making things hot and dense, 0:07:22.160 --> 0:07:24.680 and what it would like to do if it wasn't constrained, 0:07:24.960 --> 0:07:26.880 is turned that into a black hole. Right. Gravity is 0:07:26.920 --> 0:07:29.440 always just pushing and pushing and pushing, and if there's 0:07:29.520 --> 0:07:32.920 nothing else but gravity, everything would collapse into a black hole. 0:07:33.480 --> 0:07:36.800 But in the star you have lots of forces resisting gravity, 0:07:37.160 --> 0:07:39.560 and when the star is burning, the primary force at 0:07:39.560 --> 0:07:42.920 the frontier resistant gravity is fusion itself, which is pushing 0:07:43.040 --> 0:07:46.800 out with radiation, right it produces all this heat, this energy, 0:07:47.080 --> 0:07:49.760 it's pushing the star out. So fusion is pushing the 0:07:49.760 --> 0:07:52.480 star out. Gravity is pushing the star back in, and 0:07:52.520 --> 0:07:55.440 there's a balance there, and if you upset that balance, 0:07:55.680 --> 0:07:59.320 then yes, the star can go kaboom. And there's basically 0:07:59.360 --> 0:08:02.200 two ways for the star to go supernova. There's the 0:08:02.280 --> 0:08:06.080 core collapse supernova and then there's the special fancy type 0:08:06.160 --> 0:08:09.440 one A supernova, and the core collapse is the one 0:08:09.480 --> 0:08:11.800 that we mostly think about. This is like the sort 0:08:11.800 --> 0:08:15.160 of vanilla supernova. What happens is the fusion is doing 0:08:15.160 --> 0:08:18.120 its job. It's turning hydrogen into helium, and then if 0:08:18.120 --> 0:08:20.760 it's hot enough, it's turning helium into carbon, and if 0:08:20.760 --> 0:08:23.160 it's hot enough, it's turning that carbon into neon and 0:08:23.360 --> 0:08:25.960 oxygen and all sorts of heavier stuff all the way 0:08:26.040 --> 0:08:30.440 up to iron. But fusing those heavier elements requires more temperature, 0:08:30.520 --> 0:08:33.280 so a star might not be hot enough to fuse 0:08:33.320 --> 0:08:37.040 a certain element. For example, right now, our star confuse hydrogen, 0:08:37.080 --> 0:08:39.720 but it can't fuse helium. So what happens to the 0:08:39.760 --> 0:08:41.959 helium or the core of our star it just sits 0:08:41.960 --> 0:08:44.920 there and kind of gets in the way. It's like ash, 0:08:45.000 --> 0:08:47.720 it's like the product of a fire. And if you 0:08:47.800 --> 0:08:51.040 have too much of that without climbing over that temperature 0:08:51.080 --> 0:08:53.960 threshold where you can burn it, also it starts to 0:08:54.000 --> 0:08:57.040 put the fire out. So smaller stars reach their hotest 0:08:57.040 --> 0:08:59.520 temperature and can't burn something. So, for example, our star 0:08:59.559 --> 0:09:02.160 can't burn helium. If the star was larger, it would 0:09:02.160 --> 0:09:04.000 get hotter at its core and it would burn a 0:09:04.040 --> 0:09:06.720 heavier element, or a heavier element, or an even heavier 0:09:06.760 --> 0:09:09.040 element all the way up to iron. When you get 0:09:09.120 --> 0:09:12.360 up to iron, no star can burn iron and produce 0:09:12.600 --> 0:09:16.160 energy because when you fuse iron together, it actually costs energy. 0:09:16.200 --> 0:09:19.959 It cools the star. So the short version of the 0:09:20.000 --> 0:09:23.320 story is, at some point you've done so much fusion 0:09:23.520 --> 0:09:25.959 and you've made something that you can no longer burn 0:09:26.040 --> 0:09:29.480 that's interfering with your fusion, and so fusion is failing 0:09:29.559 --> 0:09:32.360 and gravity starts to win, and the star starts to 0:09:32.400 --> 0:09:35.880 collapse because remember the reason it wasn't collapsing was fusion 0:09:35.960 --> 0:09:39.840 pushing out against gravity, and now you've knocked out those supports, 0:09:40.120 --> 0:09:45.400 gravity wins, the star implodes, and that implosion then triggers 0:09:45.440 --> 0:09:48.160 a moment when the star is hot enough to do 0:09:48.200 --> 0:09:51.719 stuff like burn iron and make super heavy elements, and 0:09:51.760 --> 0:09:54.880 that triggers the explosion, which is the supernova. So the 0:09:54.920 --> 0:09:58.040 core collapse supernova comes when the core is not hot 0:09:58.160 --> 0:10:01.079 enough to burn the ash that's left over, which then 0:10:01.080 --> 0:10:03.240 triggers the collapse and then an explosion. 0:10:03.679 --> 0:10:06.319 That was a great explanation. Okay, so you said our 0:10:06.600 --> 0:10:08.920 sun is not hot enough to make iron, so we've 0:10:08.920 --> 0:10:11.440 got a bunch of helium. Does it matter what form 0:10:11.520 --> 0:10:15.080 the ash takes, they all explode no matter what kind 0:10:15.080 --> 0:10:16.760 of ash is made, or do you get a different 0:10:16.800 --> 0:10:19.079 result if the ash is helium versus if the ash 0:10:19.120 --> 0:10:20.240 gets to the iron fase. 0:10:20.400 --> 0:10:22.960 Yes, So not every star is going to go supernova, Like, 0:10:23.000 --> 0:10:25.440 for example, our star is not going to go supernova. 0:10:25.520 --> 0:10:27.800 It's not big enough. It's going to accumulate a lot 0:10:27.840 --> 0:10:30.160 of helium in its core, and then near the very 0:10:30.400 --> 0:10:33.640 end it's gonna have a brief moment like maybe minutes 0:10:33.840 --> 0:10:36.520 in the billions year long life cycle of the star 0:10:36.880 --> 0:10:39.599 where it can burn that helium and a helium flash 0:10:40.000 --> 0:10:42.440 and make a little bit of heavier stuff, but it 0:10:42.440 --> 0:10:46.160 doesn't have enough gravity to actually collapse. Fusion is gonna 0:10:46.160 --> 0:10:48.040 happen in the outer layers because the core is going 0:10:48.120 --> 0:10:50.400 to be cold helium, and then you're gonna have this 0:10:50.480 --> 0:10:53.000 helium flash and it's gonna blow off those outer layers 0:10:53.000 --> 0:10:54.840 and you're gonna be left with a white dwarf, which 0:10:54.880 --> 0:10:58.439 is just a hot blob of stuff. It's not fusing anymore. 0:10:58.440 --> 0:11:01.240 It's just like a big rock sitting there in space glowing, 0:11:01.960 --> 0:11:04.880 just a white dwarf. If it were bigger, then it 0:11:04.880 --> 0:11:08.439 would have enough gravity to actually collapse and cause a supernova. 0:11:08.600 --> 0:11:10.840 So our star is not going to become a supernova 0:11:10.920 --> 0:11:15.480 unless there is a route for white dwarfs to become supernova's. 0:11:15.720 --> 0:11:18.280 White dwarfs are just hot stuff sitting there in space, 0:11:18.720 --> 0:11:21.920 not fusing. Gravity's trying to squeeze them, but it's resisting 0:11:22.000 --> 0:11:24.200 because of the chemical strength of the stuff. The same 0:11:24.240 --> 0:11:26.920 reason why like the Earth doesn't collapse into a black hole. 0:11:26.920 --> 0:11:30.800 It's got chemical strength supporting it. But if something comes 0:11:30.800 --> 0:11:34.560 along and pours extra material onto the white dwarf, then 0:11:34.600 --> 0:11:37.520 it can increase its gravity, and gravity can overcome that 0:11:37.640 --> 0:11:40.320 strength and cause it to collapse and make a special 0:11:40.400 --> 0:11:43.079 type one a supernova. This happens if you have a 0:11:43.080 --> 0:11:46.400 white dwarf that has like a sister star nearby, and 0:11:46.440 --> 0:11:48.520 it eats some of that sister star and then it 0:11:48.559 --> 0:11:52.480 gets triggered into a supernova. So that's the second kind 0:11:52.520 --> 0:11:55.960 of supernova. So our star could eventually have a Type 0:11:55.960 --> 0:11:57.600 one a supernova, but it's not going to have a 0:11:57.600 --> 0:11:58.960 core collapse supernova. 0:11:59.440 --> 0:12:02.840 So already got into part of the answer then for 0:12:02.960 --> 0:12:05.880 why you don't get chain reactions because some of the 0:12:05.960 --> 0:12:09.400 stars in between can't explode. They're just not the right kind. 0:12:09.440 --> 0:12:12.320 They're little, they don't have sisters they can eat. Why 0:12:12.320 --> 0:12:14.520 do we always get to annibalism. I don't know, we do. 0:12:15.200 --> 0:12:17.319 And so you can't get the chain reaction because there's 0:12:17.360 --> 0:12:19.720 a lot of stars, you know, in the line that 0:12:19.800 --> 0:12:21.600 are just not capable of exploding. 0:12:21.720 --> 0:12:23.520 Yeah, you need the right kind of star. And so 0:12:23.600 --> 0:12:25.640 the answer to this question is that it's very unlikely 0:12:25.720 --> 0:12:28.280 to have lots of chain reactions, but it could be 0:12:28.320 --> 0:12:31.760 possible if you set up the conditions just perfectly. And 0:12:31.800 --> 0:12:33.920 I'm a big science fiction reader, and so when I 0:12:33.960 --> 0:12:37.400 got this question from Tama, was reminded of this snippet 0:12:37.480 --> 0:12:40.240 from a Laring Niven novel Ring World, And there's a 0:12:40.240 --> 0:12:42.199 scene where they talk about how in the center of 0:12:42.200 --> 0:12:45.240 the galaxy the stars are all packed together really really close. 0:12:45.720 --> 0:12:48.400 One star goes nova, it releases a lot of heat 0:12:48.440 --> 0:12:51.480 and gamma rays, and that heats of the neighboring stars 0:12:51.559 --> 0:12:53.720 with then blow and it sets off a chain reaction. 0:12:53.840 --> 0:12:56.400 So it's super cool idea that you could like have 0:12:56.440 --> 0:12:59.400 this like set of fireworks going off in the galaxy. 0:13:00.000 --> 0:13:01.920 In order to make this work, you really need exactly 0:13:01.920 --> 0:13:05.360 the right conditions, and what he describes in Ring World 0:13:05.440 --> 0:13:08.440 probably wouldn't happen the way he described it, because adding 0:13:08.480 --> 0:13:12.000 heat to a star doesn't actually cause it to explode. 0:13:12.480 --> 0:13:15.199 Remember we talked about core collapse supernova. The reason they 0:13:15.240 --> 0:13:18.160 collapse is because they're not hot enough. They can no 0:13:18.200 --> 0:13:21.640 longer do fusion to burn the ash that's at their core. 0:13:22.120 --> 0:13:25.160 So adding heat to a star actually supports it actually 0:13:25.200 --> 0:13:28.880 makes it more likely to live longer. It prevents its collapse. 0:13:28.880 --> 0:13:33.040 It doesn't trigger its collapse. Right, These stars explode because 0:13:33.080 --> 0:13:35.560 they no longer have fusion happening at their core. 0:13:36.120 --> 0:13:38.520 Is that true? Even if the ash is iron like 0:13:38.600 --> 0:13:41.840 the end of the process, even adding more heat won't help. 0:13:42.000 --> 0:13:44.920 Yeah, exactly, because the process of fusing iron SAPs heat 0:13:44.960 --> 0:13:46.480 from the core. So you have a bunch of iron 0:13:46.520 --> 0:13:48.839 there and the stars trying to fuse it, but that 0:13:49.000 --> 0:13:52.240 fusion process is gobbling the energy instead of creating energy. 0:13:52.240 --> 0:13:55.000 It's like the opposite of a chain reaction. And if 0:13:55.000 --> 0:13:58.080 you have an external source of heat that's fueling that, 0:13:58.080 --> 0:14:01.600 that's providing that energy, then you can sustain the star longer. 0:14:02.240 --> 0:14:06.480 So a core collapse supernova isn't triggered by external heat 0:14:06.559 --> 0:14:10.280 like radiation from another star. But the other kind of supernova, 0:14:10.280 --> 0:14:13.880 the type one A supernova, is triggered externally. Right, you 0:14:13.920 --> 0:14:16.960 have a white dwarf which otherwise wasn't going to go supernova, 0:14:17.320 --> 0:14:19.800 and you get a deposition of new material from some 0:14:20.000 --> 0:14:23.280 neighboring star that does trigger it to go over this 0:14:23.360 --> 0:14:26.480 threshold and then go supernova. And so I asked a 0:14:26.480 --> 0:14:29.600 friend of mine, David Vartagnan, he's a scientist who studies 0:14:29.640 --> 0:14:32.800 supernova's he's a Hubbele Einstein fellow at the Carnegie Observatories, 0:14:32.800 --> 0:14:36.800 and he said, quote, this may be possible for thermonuclear supernova, 0:14:36.880 --> 0:14:39.800 which requires some version of runaway nuclear chain reactions on 0:14:39.840 --> 0:14:43.280 the stellar surface. It's possible to change this if situations 0:14:43.320 --> 0:14:46.280 are just right. So the idea is that you have 0:14:46.480 --> 0:14:49.520 like a series of these white dwarfs, and you add 0:14:49.560 --> 0:14:52.160 material to one of them, it goes supernova and then 0:14:52.200 --> 0:14:55.960 deposits material on the next nearby white dwarf, which causes 0:14:56.000 --> 0:14:58.560 that to go supernova. Dot dot dot. You have a 0:14:58.640 --> 0:14:59.280 chain reaction. 0:15:00.360 --> 0:15:01.880 Do my kids have anything to worry about? 0:15:02.320 --> 0:15:04.960 You know, your kids do not have anything to worry about. 0:15:05.120 --> 0:15:07.480 But if you are designing a universe and you want 0:15:07.480 --> 0:15:10.440 to see this happen, you might be able to arrange it. 0:15:10.800 --> 0:15:12.240 So if your kids grow up to be god or 0:15:12.280 --> 0:15:15.040 masters of their own domain, they could set up a 0:15:15.080 --> 0:15:17.680 supernova chain reaction if they so desire. 0:15:18.080 --> 0:15:22.440 Malevolent guns, not the nice ones. Also, d'Artagnan super cool 0:15:22.520 --> 0:15:25.440 last name, like the polar opposite of Wiersmith. I guess 0:15:25.440 --> 0:15:28.960 maybe it reminds me of d'Artagnan like the Three Musketeers. Okay, 0:15:29.440 --> 0:15:32.280 on that note, let's get back in touch with Tim 0:15:32.400 --> 0:15:34.640 and see if he feels like his question was answered. 0:15:34.800 --> 0:15:37.120 Answer the awesome question, Tim, hope you like the answer. 0:15:37.600 --> 0:15:41.320 Oh, thanks for answering my question. Danielle and Kelly, Yeah, 0:15:41.680 --> 0:15:45.960 you answered it. I'm pretty excited to know that under 0:15:45.960 --> 0:15:49.120 the right circumstances, it can happen, so that it's possible, 0:15:49.480 --> 0:15:50.920 But it doesn't sound like we're going to have a 0:15:50.960 --> 0:15:55.360 spectacular fireworks show up exploding stars in our night sky 0:15:55.440 --> 0:15:59.960 anytime soon. So glad your kids are safe and thanks 0:16:00.040 --> 0:16:00.800 to answering my question. 0:16:17.280 --> 0:16:20.280 All right. So next we have a question from Julian 0:16:20.440 --> 0:16:24.400 from our discord, Daniel, if somebody wants to play with 0:16:24.480 --> 0:16:26.520 us on discord, where do they find the link to 0:16:26.560 --> 0:16:27.320 our discord? 0:16:27.480 --> 0:16:31.000 Go to our website www dot danieland Kelly dot org 0:16:31.040 --> 0:16:33.120 and you'll see an invitation there to the discorder. You 0:16:33.160 --> 0:16:35.920 can come and talk and ask questions and make silly 0:16:36.000 --> 0:16:36.760 jokes and. 0:16:36.680 --> 0:16:40.360 Be our friends. All right, So let's listen to a 0:16:40.480 --> 0:16:42.080 question from a New Zealander. 0:16:42.480 --> 0:16:45.320 Hi, Daniel and Kelly. I'm Julian from New Zealand, a 0:16:45.360 --> 0:16:48.440 longtime fan of the pod. What I'm interested in hearing 0:16:48.600 --> 0:16:51.680 is your opinion on the possibility of non carbon based life. 0:16:52.600 --> 0:16:56.040 Given the practically infinite size of the universe, it seems 0:16:56.040 --> 0:16:58.800 to me that we should consider other life chemistries as 0:16:58.920 --> 0:17:02.440 probable rather than But I'm interested to hear your thoughts 0:17:02.440 --> 0:17:04.840 on this and whether they would be any practical wife 0:17:04.840 --> 0:17:09.360 for us to search for barmakers from other platforms. Thanks, 0:17:09.520 --> 0:17:11.120 and keep up the great work. Bye. 0:17:11.480 --> 0:17:13.400 I love this kind of question because it takes us 0:17:13.440 --> 0:17:16.000 like out of the mindset that life on Earth is 0:17:16.000 --> 0:17:18.439 the only way life can be. So I'm dying to 0:17:18.480 --> 0:17:19.879 hear your thoughts about this, Kelly. 0:17:20.280 --> 0:17:22.560 Yeah, well, so I was really excited when I got 0:17:22.560 --> 0:17:24.440 this question because it had the word life in it, 0:17:24.880 --> 0:17:27.000 and then as I dug a little farther in, I 0:17:27.080 --> 0:17:30.920 realized this was a chemistry question, and I remain excited. 0:17:31.320 --> 0:17:33.240 But here we go. Let's do this, all right. So 0:17:33.640 --> 0:17:37.760 there's about ninety four naturally occurring elements on the periodic table, 0:17:37.920 --> 0:17:41.119 but the scaffold for life seems to be made of 0:17:41.160 --> 0:17:44.000 carbon in every case that we've ever looked at, So 0:17:44.600 --> 0:17:47.240 why carbon and why not something else? 0:17:47.440 --> 0:17:49.960 So there's ninety four naturally occurring elements. So you're talking 0:17:49.960 --> 0:17:52.639 about basically the building blocks of life out there in 0:17:52.680 --> 0:17:56.159 the universe. But if we're starting on a rocky planet, 0:17:56.200 --> 0:17:58.600 I guess we're assuming that there's like a good chunk 0:17:58.960 --> 0:18:01.400 of silica and carbon and this kind of stuff, because 0:18:01.400 --> 0:18:03.680 that's what you need to make a rocky planet, right, yep, 0:18:03.720 --> 0:18:04.399 all right, cool? 0:18:04.560 --> 0:18:07.760 You said that the sun makes everything up to iron. 0:18:07.880 --> 0:18:10.200 Is that right? Yeah, that's right, So we would expect 0:18:10.280 --> 0:18:13.199 everything up to iron to be fairly plentiful in the universe, 0:18:13.280 --> 0:18:14.000 Is that fair to say? 0:18:14.200 --> 0:18:17.040 Yeah, although there's a fascinating distribution of which elements are 0:18:17.040 --> 0:18:19.560 more common and which ones are less common, which involves 0:18:19.600 --> 0:18:22.360 a lot of chemistry, but we'll dig into it one day. 0:18:23.600 --> 0:18:25.800 So the three criteria to sort of like enter us 0:18:25.800 --> 0:18:30.879 in here is one abundance. So you wouldn't expect nobellium 0:18:30.960 --> 0:18:32.760 to be the backbone for life because there's not a 0:18:32.760 --> 0:18:35.040 lot of it out there, But the more common things, 0:18:35.119 --> 0:18:37.600 you know, they'd be easier for organic organisms to find 0:18:37.640 --> 0:18:39.800 and incorporate into their bodies. And so what are some 0:18:39.880 --> 0:18:41.520 of these common atoms? 0:18:41.800 --> 0:18:44.520 So the universe is mostly hydrogen, you know, because we 0:18:44.560 --> 0:18:47.399 started with hydrogen and stars have been making heavier stuff 0:18:47.440 --> 0:18:49.800 for a while, but we're pretty early on in the 0:18:49.840 --> 0:18:53.160 history of the universe, So mostly hydrogen. Like seventy four 0:18:53.200 --> 0:18:57.359 percent of the universe by mass fraction is hydrogen, and 0:18:57.400 --> 0:18:59.479 then a big chunk of it is helium, So like 0:18:59.520 --> 0:19:03.040 twenty four percent, which is already like most of the universe, 0:19:03.080 --> 0:19:06.080 you got seventy four percent plus twenty four percent leaves 0:19:06.119 --> 0:19:09.040 only two percent of the universe is left. But the 0:19:09.040 --> 0:19:11.840 next one is kind of a surprise. It's oxygen, right, 0:19:11.880 --> 0:19:14.840 Oxygen is much more common than anything else that's not 0:19:14.960 --> 0:19:18.399 hydrogen or helium. And then you got carbon and neon 0:19:18.600 --> 0:19:22.000 and then iron, so those are the most common building 0:19:22.000 --> 0:19:23.080 blocks in the universe. 0:19:23.320 --> 0:19:25.239 Okay, all right, so let's go from there. So all right, 0:19:25.240 --> 0:19:28.119 so abundance is criteria one. Yeah, so you need stuff 0:19:28.119 --> 0:19:30.000 that's abundant, so we're not surprised to find out that 0:19:30.040 --> 0:19:32.439 it's carbon, although carbon, as you're noted, is not as 0:19:32.480 --> 0:19:34.879 abundant as things like hydrogen, but there's still plenty of 0:19:34.920 --> 0:19:37.920 it on Earth for example. And then the next criteria 0:19:38.000 --> 0:19:40.480 is that it needs to be versatile and able to 0:19:40.520 --> 0:19:44.439 make a lot of complex molecules. So the proteins that 0:19:44.480 --> 0:19:47.320 we have these are very complex, they fold up in 0:19:47.320 --> 0:19:49.520 different ways, they're made up of lots of different kinds 0:19:49.560 --> 0:19:53.800 of elements, and the signaling molecules that bacteria make, like 0:19:53.920 --> 0:19:57.639 every biological organism has lots and lots of super complex 0:19:58.200 --> 0:20:00.400 molecules that it uses to carry out all of its 0:20:00.480 --> 0:20:03.760