1 00:00:08,480 --> 00:00:11,119 Speaker 1: Hey, Daniel, I have a light question for you. I 2 00:00:11,119 --> 00:00:13,440 Speaker 1: hope I am bright enough to answer it. See I 3 00:00:13,440 --> 00:00:15,760 Speaker 1: can tell you're taking this a little too lightly. Well, 4 00:00:15,800 --> 00:00:17,919 Speaker 1: you know, I'm happy to answer it and try to 5 00:00:18,040 --> 00:00:21,040 Speaker 1: lighten your intellectual load. Now I need a pretty awesome 6 00:00:21,079 --> 00:00:24,520 Speaker 1: answer here, something totally lit as the kids would say, 7 00:00:25,520 --> 00:00:28,040 Speaker 1: all right, what is it? I can illuminate for you? 8 00:00:28,080 --> 00:00:32,320 Speaker 1: All right, are you ready? What is a photon? Anyways, 9 00:00:33,280 --> 00:00:36,599 Speaker 1: that is not a lighthearted question, but go ahead, light 10 00:00:36,600 --> 00:00:39,519 Speaker 1: it up. Unfortunately, I don't have a very enlightening answer 11 00:00:39,600 --> 00:00:50,360 Speaker 1: for you. Just light puns. My puns are massless. Ye 12 00:00:58,000 --> 00:01:01,160 Speaker 1: Hi am or handmade cartoonists and the creator of PhD comics. 13 00:01:01,560 --> 00:01:04,400 Speaker 1: I'm Daniel. I'm a physicist and a professor at u 14 00:01:04,480 --> 00:01:07,360 Speaker 1: C Irvine, and now I find myself very light on 15 00:01:07,400 --> 00:01:12,360 Speaker 1: the puns. You're a shining example of in academia. No, 16 00:01:12,520 --> 00:01:14,800 Speaker 1: I just used up all my light puns, and now 17 00:01:14,959 --> 00:01:17,280 Speaker 1: my brain is like a black hole of ideas for 18 00:01:17,319 --> 00:01:20,360 Speaker 1: how to make more puns about light. You're dimming on 19 00:01:20,440 --> 00:01:24,160 Speaker 1: the punts there. Welcome to our podcast, Daniel and Jorge 20 00:01:24,200 --> 00:01:27,240 Speaker 1: Explain the Universe, a production of My Heart Radio in 21 00:01:27,240 --> 00:01:29,960 Speaker 1: which we try to shine a bright light on the 22 00:01:30,000 --> 00:01:34,119 Speaker 1: deepest mysteries of the universe. We wonder how everything works. 23 00:01:34,160 --> 00:01:36,440 Speaker 1: We wonder why it works at all. We wonder why 24 00:01:36,600 --> 00:01:39,920 Speaker 1: there is anything, how much of it there is, and 25 00:01:39,959 --> 00:01:42,959 Speaker 1: what rules it follows. We are amazed that we can 26 00:01:43,040 --> 00:01:46,480 Speaker 1: make sense of any of this incredible, crazy cosmos that 27 00:01:46,520 --> 00:01:49,200 Speaker 1: we find ourselves in, but we are appreciative that we can, 28 00:01:49,400 --> 00:01:52,200 Speaker 1: and we seek to share that little sliver of understanding 29 00:01:52,400 --> 00:01:54,600 Speaker 1: with you. That's right, It is a pretty amazing universe 30 00:01:54,640 --> 00:01:57,520 Speaker 1: full of light and shiny things for us to wonder 31 00:01:57,680 --> 00:02:02,800 Speaker 1: and ask questions about, like, for example, light or the 32 00:02:02,840 --> 00:02:06,760 Speaker 1: opposite of light, like black holes, big stars, giant stars, 33 00:02:06,760 --> 00:02:09,639 Speaker 1: small stars, dark matter, all kinds of things for us 34 00:02:09,639 --> 00:02:12,560 Speaker 1: to wonder about, because it's not just a universe filled 35 00:02:12,600 --> 00:02:15,200 Speaker 1: with stuff. It's a universe filled with stuff that is 36 00:02:15,280 --> 00:02:19,359 Speaker 1: sending us messages. We couldn't see stars in other solar 37 00:02:19,400 --> 00:02:22,120 Speaker 1: systems if they were not shooting light at us or 38 00:02:22,200 --> 00:02:25,960 Speaker 1: sending other kinds of particles. So don't imagine a universe 39 00:02:26,040 --> 00:02:29,480 Speaker 1: out there doing its mysterious stuff in the darkness. Instead, 40 00:02:29,760 --> 00:02:32,959 Speaker 1: all the crazy dancing that's happening in the physics inside 41 00:02:33,000 --> 00:02:35,920 Speaker 1: stars and inside black holes and all over the galaxy 42 00:02:36,320 --> 00:02:39,680 Speaker 1: is beaming you answers, beaming you clues at least to 43 00:02:39,880 --> 00:02:43,640 Speaker 1: lead you towards answers and understanding of the fundamental physics 44 00:02:43,639 --> 00:02:46,400 Speaker 1: that would explain it all. Yeah, the universe is bathing us, 45 00:02:46,400 --> 00:02:49,080 Speaker 1: but information about itself and have the laws that it 46 00:02:49,120 --> 00:02:52,520 Speaker 1: follows to make everything work, from giant stars and galaxies 47 00:02:52,600 --> 00:02:56,360 Speaker 1: to the tiny smallest molecules and particles. Assuming of course, 48 00:02:56,400 --> 00:02:59,200 Speaker 1: that the universe does follow laws. He's saying the universe 49 00:02:59,280 --> 00:03:02,520 Speaker 1: is some kind of out law, some kind of criminal universe. 50 00:03:02,639 --> 00:03:05,959 Speaker 1: Is it gon need to go to university jail. I 51 00:03:06,000 --> 00:03:08,280 Speaker 1: don't want to put a black mark on the reputation 52 00:03:08,320 --> 00:03:10,799 Speaker 1: of the universe in any sense I think you just did. 53 00:03:11,800 --> 00:03:17,040 Speaker 1: I'm just asking questions. You know, I wonder if Daniel 54 00:03:17,120 --> 00:03:20,400 Speaker 1: Whiteson broke the law again today. Is that the kind 55 00:03:20,440 --> 00:03:24,559 Speaker 1: of question that wouldn't that is harmless? Yeah? Yeah, exactly. 56 00:03:24,760 --> 00:03:27,359 Speaker 1: And I'm impressed with how well the universe so far 57 00:03:27,480 --> 00:03:30,639 Speaker 1: has been following laws, or put another way, how we've 58 00:03:30,639 --> 00:03:33,560 Speaker 1: been able to discover the laws the universe seems to 59 00:03:33,639 --> 00:03:35,840 Speaker 1: be following. But you know, there is a deep and 60 00:03:35,880 --> 00:03:39,000 Speaker 1: fundamental mystery there which is like, why is the universe 61 00:03:39,080 --> 00:03:42,800 Speaker 1: following laws at all, and is it possible to ever 62 00:03:42,880 --> 00:03:46,160 Speaker 1: come up with a single law that describes everything in 63 00:03:46,200 --> 00:03:48,160 Speaker 1: the universe. That's a little bit of an article of 64 00:03:48,200 --> 00:03:50,480 Speaker 1: faith in the whole process of science. Yeah, it's a 65 00:03:50,480 --> 00:03:53,720 Speaker 1: big question. Fortunately, the universe, as you said, is bright, 66 00:03:53,800 --> 00:03:56,120 Speaker 1: and it is full of things that shine and give 67 00:03:56,200 --> 00:03:58,560 Speaker 1: up light, and and that like gets to us, and 68 00:03:58,600 --> 00:04:02,240 Speaker 1: we can use that information to figure out if the 69 00:04:02,360 --> 00:04:06,400 Speaker 1: universe should be arrested or not. And that raises another 70 00:04:06,440 --> 00:04:08,840 Speaker 1: deep question, which is if the universe breaks the law, 71 00:04:09,040 --> 00:04:11,680 Speaker 1: who punishes it? Does it go to universe jail? In 72 00:04:11,760 --> 00:04:15,840 Speaker 1: what universe is that jail? Obviously there's a multiverse department 73 00:04:15,880 --> 00:04:20,200 Speaker 1: of justice. I'm amazed that I've never read that science 74 00:04:20,240 --> 00:04:23,760 Speaker 1: fiction novel. I think I think Marvel has it pretty 75 00:04:23,880 --> 00:04:28,720 Speaker 1: well covered. But a whole universe in jail, Wow, that's 76 00:04:28,760 --> 00:04:31,400 Speaker 1: quite the budget. Now they kill universes, oh man, they 77 00:04:31,400 --> 00:04:34,360 Speaker 1: shut them down. The death penalty for a universe. Usually 78 00:04:34,360 --> 00:04:37,120 Speaker 1: that gives me the shirts. Yeah, it's pretty pretty. It's 79 00:04:37,160 --> 00:04:40,360 Speaker 1: called the time authority. Oh that's right. Yeah, they do 80 00:04:40,480 --> 00:04:44,080 Speaker 1: cancel whole branches of the timeline. That's true. Well, let's 81 00:04:44,120 --> 00:04:46,600 Speaker 1: hope that never happens to us. We are just here 82 00:04:46,640 --> 00:04:49,760 Speaker 1: trying to figure out how the universe works. We're trusting 83 00:04:49,760 --> 00:04:52,200 Speaker 1: that it is following some laws and it's not putting 84 00:04:52,279 --> 00:04:55,839 Speaker 1: us in existential danger because we would like to understand 85 00:04:55,880 --> 00:04:58,240 Speaker 1: how it works. We look at all these photons that 86 00:04:58,279 --> 00:05:00,040 Speaker 1: come to our eyeballs and we try to make a 87 00:05:00,080 --> 00:05:03,480 Speaker 1: mental picture of how everything works. And sometimes we're confused. 88 00:05:03,560 --> 00:05:06,240 Speaker 1: Sometimes we see something we don't quite understand, and that, 89 00:05:06,320 --> 00:05:10,360 Speaker 1: of course leads to my favorite part of science, asking questions. Yeah, 90 00:05:10,360 --> 00:05:12,720 Speaker 1: and it's not just scientists who ask questions or love 91 00:05:12,760 --> 00:05:16,280 Speaker 1: to ask questions or have questions about the universe. It's everybody. 92 00:05:16,400 --> 00:05:18,120 Speaker 1: We all, at some point in our lives look up 93 00:05:18,160 --> 00:05:20,960 Speaker 1: at this guy and think, where did it all come from? 94 00:05:21,000 --> 00:05:23,640 Speaker 1: How does it all work? Why are we here? Who 95 00:05:23,720 --> 00:05:25,599 Speaker 1: is it that stole my chocolate? And how can I 96 00:05:25,600 --> 00:05:28,679 Speaker 1: put them in universe jail? These are big questions basically 97 00:05:28,720 --> 00:05:31,600 Speaker 1: everybody asks in their lifetime, because science is not just 98 00:05:31,680 --> 00:05:34,880 Speaker 1: a process that professors can do in their offices or 99 00:05:34,920 --> 00:05:38,000 Speaker 1: in their basement labs. It's just part of being human. 100 00:05:38,240 --> 00:05:41,520 Speaker 1: It's just like a way to codify and systematize the 101 00:05:41,640 --> 00:05:46,080 Speaker 1: natural feelings that we have of curiosity and investigation. It's 102 00:05:46,120 --> 00:05:48,720 Speaker 1: something that everybody can do, and it's something that everybody 103 00:05:48,760 --> 00:05:52,159 Speaker 1: is always doing as they maneuver in this world. Yeah, 104 00:05:52,160 --> 00:05:54,200 Speaker 1: all you have to do is observe the universe, think 105 00:05:54,240 --> 00:05:57,720 Speaker 1: about it, and use logic to work things out. That's 106 00:05:57,839 --> 00:06:01,440 Speaker 1: that's basically science right now. That's basically science. Also, drink coffee. 107 00:06:01,560 --> 00:06:05,479 Speaker 1: Coffee is a big part of it. I think you 108 00:06:05,480 --> 00:06:07,240 Speaker 1: don't drink any coffee anymore though, Does that mean that 109 00:06:07,279 --> 00:06:09,360 Speaker 1: you don't do any science? Well, I don't get paid 110 00:06:09,360 --> 00:06:12,440 Speaker 1: for it. If that's what you means. It's the coffee 111 00:06:12,480 --> 00:06:14,679 Speaker 1: drinking that I'm getting paid for over here, that's true. 112 00:06:14,839 --> 00:06:18,480 Speaker 1: It's the extra mile. Yeah, when you're ingest chemicals for something, 113 00:06:18,800 --> 00:06:21,320 Speaker 1: that means you're a pro. That's what goes to my 114 00:06:21,360 --> 00:06:24,479 Speaker 1: time sheets. Nine espressos today. Oh I'm getting over time, 115 00:06:25,480 --> 00:06:30,000 Speaker 1: over time, uh yeah, and overclocking your heart as well, 116 00:06:30,160 --> 00:06:33,240 Speaker 1: exactly and my brain. But what we love to do 117 00:06:33,360 --> 00:06:36,039 Speaker 1: is not just ask questions ourselves and talk about them, 118 00:06:36,080 --> 00:06:38,880 Speaker 1: but encourage you to ask questions. We hope that this 119 00:06:38,920 --> 00:06:42,840 Speaker 1: podcast tickles that inquisitive part of your brain and makes 120 00:06:42,880 --> 00:06:44,880 Speaker 1: you look around at your universe and think, do I 121 00:06:44,920 --> 00:06:47,680 Speaker 1: understand how this works? Can I figure this out? And 122 00:06:47,720 --> 00:06:49,720 Speaker 1: when you don't, we want you to write to us 123 00:06:49,760 --> 00:06:52,520 Speaker 1: with your questions so we can help you understand them. 124 00:06:52,560 --> 00:07:00,680 Speaker 1: So today on the podcast, we'll be tackling listener questions 125 00:07:01,360 --> 00:07:04,400 Speaker 1: light addition. Now it's just like a low calorie version 126 00:07:04,600 --> 00:07:08,520 Speaker 1: of our usual listener question episode. Welcome to Daniel and 127 00:07:08,600 --> 00:07:11,880 Speaker 1: Jorge on an intellectual diet. That's right, it's all cottage 128 00:07:11,960 --> 00:07:14,960 Speaker 1: cheese and can't to look today, folks, what is it? Aspertame? 129 00:07:15,320 --> 00:07:19,120 Speaker 1: We're going to give aspertain answers, the sweetest questions to 130 00:07:19,160 --> 00:07:23,480 Speaker 1: the sweetest mysteries in science, but with no calories. It's 131 00:07:23,480 --> 00:07:25,680 Speaker 1: gonna feel sweet when you listen to our answers, but 132 00:07:26,240 --> 00:07:28,720 Speaker 1: don't worry, you're not going to learn anything that is 133 00:07:29,360 --> 00:07:33,720 Speaker 1: promising here. Or maybe we should have very heavy answers 134 00:07:33,720 --> 00:07:36,160 Speaker 1: and people should like bench press us, you know, like 135 00:07:36,240 --> 00:07:40,840 Speaker 1: really massive, deep answers to the heaviest questions in the universe. 136 00:07:41,200 --> 00:07:44,360 Speaker 1: Maybe that should be a different podcast, the heavy edition, 137 00:07:44,560 --> 00:07:47,520 Speaker 1: the fitness version. The massive addition. We should be playing 138 00:07:47,520 --> 00:07:49,600 Speaker 1: like fitness music in the background, so I've already can 139 00:07:49,640 --> 00:07:52,160 Speaker 1: be like doing their crunches as they listen. That might 140 00:07:52,200 --> 00:07:54,400 Speaker 1: make it a little hard to talk. Yeah, I would 141 00:07:54,400 --> 00:07:56,560 Speaker 1: think of physicists would know that. But we do love 142 00:07:56,640 --> 00:07:59,920 Speaker 1: encouraging you to ask questions and to send us your question. 143 00:08:00,280 --> 00:08:02,480 Speaker 1: If you have questions about the way the universe works, 144 00:08:02,600 --> 00:08:05,800 Speaker 1: or there's something that's always puzzled you, please please please 145 00:08:05,840 --> 00:08:08,960 Speaker 1: write to us two questions at Daniel and Jorge dot com. 146 00:08:09,280 --> 00:08:12,520 Speaker 1: We answer all our emails. We answer all these questions, 147 00:08:12,640 --> 00:08:15,280 Speaker 1: and sometimes we might pick your question to answer here 148 00:08:15,400 --> 00:08:18,000 Speaker 1: on the podcast. Yeah, so today we have three awesome 149 00:08:18,080 --> 00:08:20,679 Speaker 1: questions and they're all in one way or another about 150 00:08:20,960 --> 00:08:25,280 Speaker 1: light kind of right or the lack thereof perhaps, Yeah, exactly, photons, 151 00:08:25,280 --> 00:08:27,000 Speaker 1: what they do when they hit stuff, how far they 152 00:08:27,040 --> 00:08:30,520 Speaker 1: can travel, and what's going on inside a black hole? 153 00:08:30,800 --> 00:08:33,200 Speaker 1: As always, I feel like everything comes back to the 154 00:08:33,200 --> 00:08:36,360 Speaker 1: black hole, one of the most massive mysteries in science. 155 00:08:36,400 --> 00:08:38,480 Speaker 1: Feel like it's kind of the rug for physicist. When 156 00:08:38,480 --> 00:08:40,760 Speaker 1: you hit a question that you don't know the answer to, 157 00:08:40,880 --> 00:08:45,480 Speaker 1: you're like, black hole on there. Why didn't I answer 158 00:08:45,480 --> 00:08:47,480 Speaker 1: your email? Oh it must have been routed into a 159 00:08:47,520 --> 00:08:51,200 Speaker 1: black hole. My apologies. So that works. Yeah, an email 160 00:08:51,200 --> 00:08:54,040 Speaker 1: black hole. That's how I would describe my regular imbob 161 00:08:54,520 --> 00:08:57,520 Speaker 1: exactly want to exceed a certain number of unread messages, 162 00:08:57,520 --> 00:09:01,000 Speaker 1: it just collapses. It creates a distorted and uh in 163 00:09:01,120 --> 00:09:03,560 Speaker 1: space and time? Yeah, all right, we'll start here with 164 00:09:03,600 --> 00:09:06,760 Speaker 1: our first question, which is about photons and what happens 165 00:09:06,760 --> 00:09:09,880 Speaker 1: when they hit stuff? And this question comes from Matthew 166 00:09:11,280 --> 00:09:15,480 Speaker 1: Daniel and horror. Hey, what's up? I loved the episode 167 00:09:15,679 --> 00:09:19,440 Speaker 1: about photons bumping into each other, but it really got 168 00:09:19,480 --> 00:09:25,120 Speaker 1: my brain spinning here, which is not difficult. What happens 169 00:09:25,160 --> 00:09:29,280 Speaker 1: to photons when they hit my skin? Are they just 170 00:09:29,600 --> 00:09:35,000 Speaker 1: absorbed and turned my skin a beautiful golden brown? What 171 00:09:35,120 --> 00:09:38,520 Speaker 1: happens when they hit solar panels? Why do things heat 172 00:09:38,600 --> 00:09:43,439 Speaker 1: up when they're hit by photons? What happens when photons 173 00:09:43,520 --> 00:09:48,360 Speaker 1: hit the opaque plastic cover on my little camper and 174 00:09:48,400 --> 00:09:50,760 Speaker 1: I can see light through it? Do some get through 175 00:09:50,800 --> 00:09:53,800 Speaker 1: and some don't? What happens when photons hit a mirror? 176 00:09:54,240 --> 00:09:58,359 Speaker 1: What happens when photons hit rock versus water, versus clouds? 177 00:10:00,200 --> 00:10:04,560 Speaker 1: I think you get the point. Boy, let's uh, let's 178 00:10:04,559 --> 00:10:12,679 Speaker 1: really dig in. It's going to be fotastic. All right, Wow, 179 00:10:12,720 --> 00:10:16,120 Speaker 1: I love that question. Yeah, that question or questions that 180 00:10:16,240 --> 00:10:19,920 Speaker 1: was like twenty different questions there. It was fotastic do 181 00:10:20,000 --> 00:10:22,000 Speaker 1: you think he was eating a bowl of fun as 182 00:10:22,000 --> 00:10:24,840 Speaker 1: he was thinking about these things. Hopefully it was diet foe. Yeah. 183 00:10:25,760 --> 00:10:27,840 Speaker 1: But uh, well, first of all, we should just say 184 00:10:27,920 --> 00:10:31,199 Speaker 1: what's up? Pat you back to you. Let me just 185 00:10:31,240 --> 00:10:34,040 Speaker 1: say how much I enjoyed hearing him spin out on 186 00:10:34,080 --> 00:10:38,320 Speaker 1: this question, realizing that there are really basic, deep questions 187 00:10:38,360 --> 00:10:41,600 Speaker 1: about how photons interact with matter and everything around us. 188 00:10:41,640 --> 00:10:43,760 Speaker 1: It is really complicated, So thank you very much for 189 00:10:43,800 --> 00:10:45,800 Speaker 1: inviting us to dig into it. Yeah. I think he 190 00:10:45,840 --> 00:10:48,120 Speaker 1: seemed to expand in his head as he was asking 191 00:10:48,160 --> 00:10:50,800 Speaker 1: the question on the idea that first of all, light 192 00:10:50,920 --> 00:10:54,520 Speaker 1: is everywhere. It's bouncing around everything and hitting everything. But 193 00:10:54,600 --> 00:10:57,199 Speaker 1: also there's kind of a huge variety of things that 194 00:10:57,360 --> 00:10:59,760 Speaker 1: like does. When it does seem to hit things right, 195 00:10:59,800 --> 00:11:02,280 Speaker 1: some lines, that goes through things, sometimes it bounces back, 196 00:11:02,360 --> 00:11:05,520 Speaker 1: sometimes it gets absorbed, sometimes it heats things up right, 197 00:11:05,559 --> 00:11:08,559 Speaker 1: there's kind of a wide range of things that light does. Yes, 198 00:11:08,760 --> 00:11:11,760 Speaker 1: light is very amazing and very complicated, and even though 199 00:11:11,800 --> 00:11:14,920 Speaker 1: it's everywhere in the world, it does react very differently 200 00:11:15,000 --> 00:11:17,400 Speaker 1: to different kinds of stuff. It's a great way to 201 00:11:17,400 --> 00:11:21,040 Speaker 1: show off like the fundamental quantum mechanics of our universe. 202 00:11:21,280 --> 00:11:24,480 Speaker 1: To understand all these different behaviors when light hits different 203 00:11:24,559 --> 00:11:28,200 Speaker 1: kinds of stuff. Yeah, so let's dig in, as Matthew requested, 204 00:11:28,600 --> 00:11:31,720 Speaker 1: So Daniel's started with the basics. What is light? What 205 00:11:31,880 --> 00:11:33,680 Speaker 1: is this thing we call light? Yeah? So the short 206 00:11:33,720 --> 00:11:36,679 Speaker 1: answer is, we really just don't know. Done. If we 207 00:11:36,720 --> 00:11:38,160 Speaker 1: don't know what light is and we don't know what 208 00:11:38,240 --> 00:11:41,920 Speaker 1: it does when it hits other things. Next question. We 209 00:11:41,960 --> 00:11:43,720 Speaker 1: don't know what light is in the sense that we 210 00:11:43,760 --> 00:11:47,000 Speaker 1: don't have like a good intuitive analog. I can't say 211 00:11:47,120 --> 00:11:49,800 Speaker 1: it's like a beach ball, or it's like a wave 212 00:11:49,920 --> 00:11:53,360 Speaker 1: in water. It's not like anything else we know. On 213 00:11:53,400 --> 00:11:57,080 Speaker 1: the other hand, we do have a very nice mathematical 214 00:11:57,160 --> 00:12:00,719 Speaker 1: description of what light does, so we can predict very 215 00:12:00,760 --> 00:12:03,679 Speaker 1: well what happens when light hits metal, or when light 216 00:12:03,760 --> 00:12:06,680 Speaker 1: hits plastic, or when light hits water, or when light 217 00:12:06,760 --> 00:12:09,600 Speaker 1: hits your skin. We can do all those calculations even 218 00:12:09,640 --> 00:12:12,720 Speaker 1: if we don't fundamentally know what light is in the 219 00:12:12,760 --> 00:12:15,640 Speaker 1: sense that we can't like translate it into something familiar. Wait, 220 00:12:15,679 --> 00:12:16,800 Speaker 1: what do you mean we don't know what it is? 221 00:12:16,840 --> 00:12:20,960 Speaker 1: I thought that light was, you know, excitations or wiggles 222 00:12:21,040 --> 00:12:25,360 Speaker 1: in the electromagnetic field that propagates across the universe, right, 223 00:12:25,440 --> 00:12:27,600 Speaker 1: isn't that the idea that the universe is filled with 224 00:12:27,679 --> 00:12:31,720 Speaker 1: quantum fields and the electromagnetic force is one of them, 225 00:12:31,840 --> 00:12:34,240 Speaker 1: and the wiggles in it are the photons. Yeah, that's 226 00:12:34,280 --> 00:12:38,280 Speaker 1: part of the mathematical description of how light works. We 227 00:12:38,360 --> 00:12:41,920 Speaker 1: can model light as a wiggle in the electromagnetic field, 228 00:12:42,400 --> 00:12:44,920 Speaker 1: and what happens to light when it hits something can 229 00:12:44,960 --> 00:12:48,920 Speaker 1: be predicted by solutions to these wave equations, which we 230 00:12:48,960 --> 00:12:51,920 Speaker 1: know mostly how to deal with in lots of circumstances, 231 00:12:51,920 --> 00:12:53,880 Speaker 1: like when they hit a barrier, or when they go 232 00:12:54,000 --> 00:12:56,120 Speaker 1: from air to water, or when it goes from air 233 00:12:56,160 --> 00:12:58,920 Speaker 1: to skin. We know mostly how to solve these problems. 234 00:12:59,160 --> 00:13:01,480 Speaker 1: We don't know what light is in the sense that 235 00:13:01,520 --> 00:13:04,199 Speaker 1: we don't really understand the fundamental quantum mechanics of it. 236 00:13:04,280 --> 00:13:06,160 Speaker 1: Like light is a wave in the sense that it's 237 00:13:06,200 --> 00:13:09,719 Speaker 1: fluctuations in this electromagnetic field. On the other hand, it 238 00:13:09,840 --> 00:13:12,800 Speaker 1: also acts like a particle because you can't observe all 239 00:13:12,840 --> 00:13:15,760 Speaker 1: of these waves directly. What you see are individual packets 240 00:13:15,760 --> 00:13:17,800 Speaker 1: of light that like go here or go there. So 241 00:13:17,800 --> 00:13:21,920 Speaker 1: there's something fundamentally probabilistic and quantum mechanical about light, and 242 00:13:21,960 --> 00:13:24,800 Speaker 1: in that sense, we don't really know like what light is, 243 00:13:25,000 --> 00:13:27,360 Speaker 1: that we do have the mathematics to describe it. Well, 244 00:13:27,360 --> 00:13:30,640 Speaker 1: you could also say that about everything else in the universe, right, 245 00:13:30,840 --> 00:13:33,800 Speaker 1: all the matter particles, all of the force particles, they're 246 00:13:33,800 --> 00:13:38,120 Speaker 1: all just quantum mechanical wave packets. Right. Yeah, absolutely, we 247 00:13:38,120 --> 00:13:41,120 Speaker 1: don't know, for example, what a particle is. My whole 248 00:13:41,160 --> 00:13:44,760 Speaker 1: episode talking about the various philosophical ideas for what it is. 249 00:13:45,000 --> 00:13:47,920 Speaker 1: That doesn't stop us from having a theory about it 250 00:13:48,200 --> 00:13:50,800 Speaker 1: and having mathematics that describe it, even if we don't 251 00:13:50,840 --> 00:13:54,719 Speaker 1: know who the subject of that mathematical story is. Right, 252 00:13:54,760 --> 00:13:56,920 Speaker 1: So if you ask me, like what is light? Then 253 00:13:57,000 --> 00:13:59,520 Speaker 1: boo boy, that's a whole big philosophical question. If you 254 00:13:59,559 --> 00:14:02,199 Speaker 1: ask me, can you predict what happens when light hits 255 00:14:02,200 --> 00:14:06,760 Speaker 1: a mirror? Oh? Yeah, that I can certainly do. Well. Fortunately, 256 00:14:06,760 --> 00:14:10,760 Speaker 1: this is not a philosophy podcast, so we'll just focus 257 00:14:10,800 --> 00:14:14,400 Speaker 1: on the latter part of describing light as as waves 258 00:14:14,400 --> 00:14:18,439 Speaker 1: any electromagnetic field. And you're saying that we can with 259 00:14:18,480 --> 00:14:21,720 Speaker 1: that description of light, we can tell what happens when 260 00:14:21,720 --> 00:14:23,960 Speaker 1: it hits different things. Yeah, that's right. We think about 261 00:14:24,000 --> 00:14:26,360 Speaker 1: light is a little packet of energy, a little pulse 262 00:14:26,400 --> 00:14:29,600 Speaker 1: in the electromagnetic field propagating through the universe. So you 263 00:14:29,600 --> 00:14:32,440 Speaker 1: imagine like light coming out of the star and flying 264 00:14:32,480 --> 00:14:34,880 Speaker 1: through space and making it through the atmosphere and hitting 265 00:14:34,920 --> 00:14:38,240 Speaker 1: your skin. And his first question was, like, what happens 266 00:14:38,280 --> 00:14:41,920 Speaker 1: to that photon? Right? Is it just like absorbed? Right? Well, 267 00:14:42,280 --> 00:14:45,040 Speaker 1: hopefully he's wearing sunscreen if he's out there in the sun, 268 00:14:45,160 --> 00:14:49,920 Speaker 1: and most of it will get refracted, refracted, reflected. But 269 00:14:50,480 --> 00:14:53,000 Speaker 1: maybe just step us through the basics, like what happens 270 00:14:53,000 --> 00:14:55,960 Speaker 1: when one of these packets of energy in the electromagnetic 271 00:14:56,000 --> 00:15:00,080 Speaker 1: field runs into a matter particle like an electron on 272 00:15:00,240 --> 00:15:02,760 Speaker 1: or maybe like an atom, like the atoms and the skin. 273 00:15:02,920 --> 00:15:04,400 Speaker 1: What's going on? So if you want to think about 274 00:15:04,400 --> 00:15:06,920 Speaker 1: in terms of an individual particle of light, then you 275 00:15:06,960 --> 00:15:09,760 Speaker 1: can imagine like the photon flying through space and it 276 00:15:09,920 --> 00:15:12,080 Speaker 1: hits the matter. Matter, of course, is made of other 277 00:15:12,120 --> 00:15:15,440 Speaker 1: little particles, and so the photon interacts with that matter. 278 00:15:15,520 --> 00:15:17,760 Speaker 1: It's not like the photon hits your skin as a 279 00:15:17,880 --> 00:15:21,600 Speaker 1: whole big blob. It touches like one particle of your skin. 280 00:15:21,880 --> 00:15:24,960 Speaker 1: It would like zero in on a single electron in 281 00:15:25,040 --> 00:15:28,240 Speaker 1: an atom on the surface of your skin and interact 282 00:15:28,440 --> 00:15:30,680 Speaker 1: with that electron. And one thing that it can do, 283 00:15:30,760 --> 00:15:33,760 Speaker 1: for example, is it can be absorbed by that electron. 284 00:15:33,920 --> 00:15:37,440 Speaker 1: Electrons can just eat photons, and then that electron now 285 00:15:37,600 --> 00:15:40,440 Speaker 1: has the energy of that photon. Yeah, that's pretty well. 286 00:15:40,440 --> 00:15:43,920 Speaker 1: Although you said that the photon touches a matter particle 287 00:15:43,960 --> 00:15:46,480 Speaker 1: in your skin, but that's not actually true, right, or 288 00:15:46,560 --> 00:15:49,440 Speaker 1: at least the idea of things touching each other is 289 00:15:49,520 --> 00:15:53,680 Speaker 1: kind of controversial or philosophical. Really, what happens is that 290 00:15:53,720 --> 00:15:56,120 Speaker 1: they get close enough to each other where they have 291 00:15:56,160 --> 00:15:59,200 Speaker 1: some kind of quantum interaction. Right. Well, the quantum interaction 292 00:15:59,240 --> 00:16:02,680 Speaker 1: here is two fields coupling directly, Like you have the 293 00:16:02,720 --> 00:16:06,400 Speaker 1: electron field and the photon field, and they overlap in 294 00:16:06,560 --> 00:16:10,120 Speaker 1: space and energy passes from one field to another. That's 295 00:16:10,160 --> 00:16:12,800 Speaker 1: the fundamental way we describe an interaction is passing of 296 00:16:12,920 --> 00:16:15,280 Speaker 1: energy from one field to another. If you're talking about 297 00:16:15,280 --> 00:16:18,440 Speaker 1: two matter particles like two electrons, Yeah, they don't actually 298 00:16:18,480 --> 00:16:21,600 Speaker 1: touch because they communicate through a photon. Right, So two 299 00:16:21,600 --> 00:16:25,480 Speaker 1: electrons don't push against each other directly. They pass photons 300 00:16:25,520 --> 00:16:28,720 Speaker 1: back and forth. But a photon interacts directly with an electron. 301 00:16:28,720 --> 00:16:32,960 Speaker 1: Its energy flows from the electromagnetic field into the electron field, right, 302 00:16:33,000 --> 00:16:35,200 Speaker 1: But I guess I mean like that there's no actual touching. 303 00:16:35,240 --> 00:16:37,280 Speaker 1: It's just that the one wiggle gets close enough to 304 00:16:37,320 --> 00:16:39,880 Speaker 1: the other wiggle where they somehow, through the magic of 305 00:16:39,920 --> 00:16:42,840 Speaker 1: the universe, the energy gets transferred from one field to 306 00:16:42,840 --> 00:16:45,240 Speaker 1: the other. I guess that's what touching is, right. So 307 00:16:45,280 --> 00:16:48,720 Speaker 1: then now we're in a philosophy podcast again. But that's 308 00:16:48,720 --> 00:16:50,760 Speaker 1: an interesting way to think about it, is that it's 309 00:16:50,800 --> 00:16:55,160 Speaker 1: it's like energy going from the photon field to the 310 00:16:55,200 --> 00:16:58,600 Speaker 1: electron field, right, Like that just magically happens. Is there 311 00:16:58,600 --> 00:17:01,240 Speaker 1: there's no conduit, there's no channel for that to happen. 312 00:17:01,320 --> 00:17:04,639 Speaker 1: That just automatically happens. These fields are sort of like, uh, 313 00:17:04,840 --> 00:17:06,840 Speaker 1: kind of on top of each other in that way. Yeah, 314 00:17:06,880 --> 00:17:09,520 Speaker 1: as you said, space is filled with these quantum fields. 315 00:17:09,640 --> 00:17:11,439 Speaker 1: Is a bunch of them. Is one for electrons, is 316 00:17:11,440 --> 00:17:13,720 Speaker 1: one for quarks, is one for photons, is one for 317 00:17:13,760 --> 00:17:16,320 Speaker 1: every kind of particle. A lot of those fields ignore 318 00:17:16,320 --> 00:17:18,320 Speaker 1: each other, but some of the fields don't. Some of 319 00:17:18,320 --> 00:17:20,679 Speaker 1: the fields do talk to each other. We call that 320 00:17:20,720 --> 00:17:23,680 Speaker 1: a coupling, and that coupling is determined by the charges 321 00:17:23,800 --> 00:17:26,959 Speaker 1: of the particles. So, for example, the photon field can 322 00:17:27,000 --> 00:17:29,480 Speaker 1: pass energy to any field. For a particle that has 323 00:17:29,520 --> 00:17:32,080 Speaker 1: an electric charge, that's actually kind of what it means 324 00:17:32,119 --> 00:17:34,399 Speaker 1: to have an electric charge. So yeah, the energy can 325 00:17:34,400 --> 00:17:37,720 Speaker 1: pass directly from the photon field to the electron field. 326 00:17:38,119 --> 00:17:41,240 Speaker 1: Like mathematically, when we describe these fields, we write them 327 00:17:41,280 --> 00:17:43,840 Speaker 1: down together in the lagrange and of the standard model, 328 00:17:43,880 --> 00:17:45,920 Speaker 1: and we add a term in front of them which 329 00:17:45,960 --> 00:17:48,240 Speaker 1: is not zero, which means that energy can pass from 330 00:17:48,240 --> 00:17:51,240 Speaker 1: one field to the other. So when the photon flies 331 00:17:51,280 --> 00:17:53,639 Speaker 1: out of the sun and hits your skin, that energy 332 00:17:53,720 --> 00:17:56,960 Speaker 1: is propagating through the electromagnetic field and now into the 333 00:17:57,000 --> 00:18:00,680 Speaker 1: electron field. It's absorbed by the electron. Okay, so that's 334 00:18:00,680 --> 00:18:02,520 Speaker 1: one thing that can happen to the photon. It can 335 00:18:02,520 --> 00:18:06,720 Speaker 1: get absorbed by the electron, and then after that a 336 00:18:06,760 --> 00:18:08,919 Speaker 1: couple of other things can happen. Right. Yeah, it's possible 337 00:18:08,960 --> 00:18:11,800 Speaker 1: for that electron to then release that energy like back 338 00:18:11,840 --> 00:18:15,000 Speaker 1: into the photon field. Right. That's a two directional interaction. 339 00:18:15,320 --> 00:18:18,600 Speaker 1: Electrons can eat photons, They can also create photons. They 340 00:18:18,600 --> 00:18:21,639 Speaker 1: can spit photons out. That electron, for example, has a 341 00:18:21,640 --> 00:18:24,119 Speaker 1: bunch of energy now, and the universe doesn't like to 342 00:18:24,200 --> 00:18:26,880 Speaker 1: have energy density very high in one place. It likes 343 00:18:26,920 --> 00:18:30,320 Speaker 1: to relax, likes to roll down to lower potential energy. 344 00:18:30,400 --> 00:18:32,360 Speaker 1: So the electron, one thing you can do is jump 345 00:18:32,440 --> 00:18:35,119 Speaker 1: back down in energy and give off a photon again. 346 00:18:35,320 --> 00:18:37,200 Speaker 1: And that can happen lots of different ways. You can 347 00:18:37,240 --> 00:18:40,600 Speaker 1: call that reflection, you can call that fluorescence. But that's 348 00:18:40,680 --> 00:18:42,600 Speaker 1: one thing that the bit of matter can do is 349 00:18:42,640 --> 00:18:45,680 Speaker 1: they can spit that photon back out into the universe. Yeah. 350 00:18:46,000 --> 00:18:48,240 Speaker 1: I guess there's two interesting things about that. One is that, 351 00:18:48,560 --> 00:18:51,600 Speaker 1: first of all, the original photon is basically god right, 352 00:18:52,359 --> 00:18:55,280 Speaker 1: like when we think of light bouncing off of a 353 00:18:55,280 --> 00:18:58,280 Speaker 1: mirror or bouncing off of your skin, like, Actually, what's 354 00:18:58,280 --> 00:19:01,119 Speaker 1: happening is that the photon die is right, It disappears 355 00:19:01,160 --> 00:19:04,080 Speaker 1: into that electron, and then a neil photon gets split 356 00:19:04,119 --> 00:19:07,160 Speaker 1: out by that electron. You know, you keep saying we're 357 00:19:07,160 --> 00:19:09,800 Speaker 1: not a philosophy podcast, and then you keep asking philosophy 358 00:19:09,880 --> 00:19:13,760 Speaker 1: questions like is the photon killed when it's absorbed? You know, 359 00:19:14,200 --> 00:19:17,120 Speaker 1: it's really interesting question, is it the same photon? Well, 360 00:19:17,320 --> 00:19:20,119 Speaker 1: that photon didn't exist for a moment. It was absorbed 361 00:19:20,160 --> 00:19:24,280 Speaker 1: into the electron. It's quantum information still exists, right, It's 362 00:19:24,320 --> 00:19:27,800 Speaker 1: certainly correlated with the original photon, So it's not like 363 00:19:27,880 --> 00:19:31,120 Speaker 1: there's no relationship between the new photon and the old photon. 364 00:19:31,400 --> 00:19:33,720 Speaker 1: But yeah, you might say it's a new photon, it's 365 00:19:33,760 --> 00:19:35,879 Speaker 1: not the same one, I guess. I mean, like in 366 00:19:35,920 --> 00:19:38,920 Speaker 1: your views of physicists, is that like an actual sequence 367 00:19:38,920 --> 00:19:43,360 Speaker 1: of events, Like the photon got absorbed, the electron realized 368 00:19:43,359 --> 00:19:45,720 Speaker 1: it had too much energy, so then it powered down 369 00:19:45,760 --> 00:19:49,320 Speaker 1: and spit out a new photon, Like, is there a 370 00:19:49,359 --> 00:19:51,440 Speaker 1: certain amount of time that happens in and it was 371 00:19:51,440 --> 00:19:56,760 Speaker 1: certain order in which it happens. It's not an instantaneous process, right. 372 00:19:56,800 --> 00:19:59,240 Speaker 1: The electron can absorb a photon and can hold onto 373 00:19:59,240 --> 00:20:00,800 Speaker 1: it for a little while, and then it can give 374 00:20:00,800 --> 00:20:03,760 Speaker 1: it up later with a podcast episode about that process. 375 00:20:03,760 --> 00:20:06,679 Speaker 1: It's called fluorescence, and that can be quite delayed, and 376 00:20:06,720 --> 00:20:08,880 Speaker 1: there certainly can be a time gap. On the other hand, 377 00:20:09,000 --> 00:20:12,120 Speaker 1: sometimes the electron gives it up almost immediately, and it's 378 00:20:12,160 --> 00:20:15,879 Speaker 1: more like the photon bounces off of the electron. For example, 379 00:20:15,880 --> 00:20:18,399 Speaker 1: in a mirror. What happens is that the photon is 380 00:20:18,440 --> 00:20:22,760 Speaker 1: basically just immediately reflected, though it is momentarily held by 381 00:20:22,800 --> 00:20:25,879 Speaker 1: the electron. And it's important to consider the other things 382 00:20:25,920 --> 00:20:28,240 Speaker 1: that can happen. It's not necessarily the case that the 383 00:20:28,280 --> 00:20:31,399 Speaker 1: electron gives up that photon. There are other options. It 384 00:20:31,440 --> 00:20:33,879 Speaker 1: can pass that energy to the nucleus of the atom 385 00:20:34,000 --> 00:20:36,920 Speaker 1: or into the lattice of the material, basically heating it up. 386 00:20:37,280 --> 00:20:39,920 Speaker 1: So there's a few varieties of things that can happen 387 00:20:39,960 --> 00:20:43,480 Speaker 1: to the electron after it's absorbed the photon. All right, man, 388 00:20:43,520 --> 00:20:46,399 Speaker 1: maybe walk us through a little bit of those options. 389 00:20:46,440 --> 00:20:49,840 Speaker 1: So how does it impart energy to the nucleus. So 390 00:20:49,840 --> 00:20:52,240 Speaker 1: the electron is interacting with the nucleus in the same 391 00:20:52,240 --> 00:20:54,400 Speaker 1: way the electron can interact with the photon, right, it's 392 00:20:54,480 --> 00:20:58,240 Speaker 1: bound to the nucleus, and it's also interacting with other 393 00:20:58,320 --> 00:21:01,520 Speaker 1: electrons in the material. And so in the same way 394 00:21:01,520 --> 00:21:03,119 Speaker 1: that it can like give up a photon, it can 395 00:21:03,160 --> 00:21:06,560 Speaker 1: also bump up against other electrons or can push up 396 00:21:06,600 --> 00:21:08,879 Speaker 1: against the nucleus. All of these, of course would be 397 00:21:08,920 --> 00:21:12,760 Speaker 1: mediated by other virtual photons. But basically, instead of just 398 00:21:12,840 --> 00:21:15,640 Speaker 1: giving up that photon back out into space, it can 399 00:21:15,680 --> 00:21:17,680 Speaker 1: create a photon which is absorbed by like the next 400 00:21:17,760 --> 00:21:20,960 Speaker 1: atom or by another particle, and that particle can have 401 00:21:21,000 --> 00:21:24,280 Speaker 1: that energy in terms of like its vibration or its rotation. 402 00:21:24,640 --> 00:21:27,399 Speaker 1: There's lots of ways for energy to be stored in matter, 403 00:21:27,760 --> 00:21:31,000 Speaker 1: and once the electron has absorbed that photon, it's possible 404 00:21:31,000 --> 00:21:32,880 Speaker 1: for that photon to get into like many of these 405 00:21:32,920 --> 00:21:35,240 Speaker 1: different kinds of buckets. All right, well, let's get into 406 00:21:35,320 --> 00:21:38,040 Speaker 1: some of the examples of what like does as it 407 00:21:38,119 --> 00:21:41,840 Speaker 1: hits different materials and whether or not it dies or not. 408 00:21:42,000 --> 00:21:56,520 Speaker 1: But first let's take a quick break. All right, we're 409 00:21:56,560 --> 00:21:59,639 Speaker 1: answering listener questions today, and our first one was about 410 00:22:00,080 --> 00:22:04,399 Speaker 1: light and basically what happens when light hits stuff, and 411 00:22:04,440 --> 00:22:07,879 Speaker 1: we talked about how it's actually photons in the electromagnetic 412 00:22:07,960 --> 00:22:11,960 Speaker 1: field hitting the particles in the atoms of the things 413 00:22:11,960 --> 00:22:14,760 Speaker 1: that you're trying to shed a light on. And one 414 00:22:14,760 --> 00:22:16,960 Speaker 1: thing it can do, it can be reflected back, or 415 00:22:16,960 --> 00:22:20,320 Speaker 1: it can the electrons can spit out basically an identical 416 00:22:20,440 --> 00:22:23,359 Speaker 1: photon back in the same direction or sort of the 417 00:22:23,400 --> 00:22:26,439 Speaker 1: same direction that the initial photon came in at. But 418 00:22:26,640 --> 00:22:30,119 Speaker 1: you're saying, you could also absorb that photon and you know, 419 00:22:30,200 --> 00:22:32,719 Speaker 1: give the atom more energy or the material it hit 420 00:22:32,800 --> 00:22:35,639 Speaker 1: more energy. That's kind of what happens when you you're 421 00:22:35,680 --> 00:22:38,000 Speaker 1: sitting out in the sun heating up right. Yeah, that 422 00:22:38,359 --> 00:22:41,600 Speaker 1: energy comes from the sun via photons and gets absorbed 423 00:22:41,640 --> 00:22:44,520 Speaker 1: by your body. When you feel hot, that's because the 424 00:22:44,560 --> 00:22:47,639 Speaker 1: atoms in your body are moving faster, they're wiggling or 425 00:22:47,640 --> 00:22:51,080 Speaker 1: sliding around faster, and then energy comes from the photon. 426 00:22:51,560 --> 00:22:54,000 Speaker 1: So yeah, that photon is now like gone. You know, 427 00:22:54,080 --> 00:22:55,800 Speaker 1: maybe every time you sit in the sun you need 428 00:22:55,840 --> 00:22:58,320 Speaker 1: to have like ten to the twenty six funerals for 429 00:22:58,359 --> 00:23:00,680 Speaker 1: all the photons that you're killing. Yeah, it's pretty sad. 430 00:23:01,680 --> 00:23:04,840 Speaker 1: You sound really sad. That's why you should cover yourself 431 00:23:04,840 --> 00:23:07,240 Speaker 1: in a liminum foil or mirrors, or just never go 432 00:23:07,320 --> 00:23:08,800 Speaker 1: outside your house. That's right. If you want to be 433 00:23:08,840 --> 00:23:12,560 Speaker 1: a photo vegan, that's right, you can join the Society 434 00:23:12,640 --> 00:23:15,919 Speaker 1: for the Humane Treatment of Photons. But so that's I 435 00:23:15,920 --> 00:23:20,680 Speaker 1: guess that's reflection and that's absorption. What about refraction, like 436 00:23:20,880 --> 00:23:23,199 Speaker 1: he asked, like, what happens when the light hits like 437 00:23:23,240 --> 00:23:27,919 Speaker 1: a semi opaque window like in his camper or you know, 438 00:23:27,960 --> 00:23:31,399 Speaker 1: something that's translucent. Maybe what's what's going on there? How 439 00:23:31,400 --> 00:23:34,880 Speaker 1: does refraction work? So refraction is complicated. To understand from 440 00:23:34,920 --> 00:23:38,720 Speaker 1: this like microphysical picture of a single article, then you 441 00:23:38,760 --> 00:23:40,920 Speaker 1: have to back up and really remember that the path 442 00:23:40,960 --> 00:23:44,359 Speaker 1: of a photon is determined by the wave equations that 443 00:23:44,400 --> 00:23:48,200 Speaker 1: are guiding its motion through the electromagnetic field. Refraction is 444 00:23:48,280 --> 00:23:51,720 Speaker 1: very familiar wave phenomena. When a wave hits another kind 445 00:23:51,720 --> 00:23:55,080 Speaker 1: of material, part of it reflects, part of it gets transmitted, 446 00:23:55,240 --> 00:23:57,640 Speaker 1: and then it gets bent in a slightly different direction. 447 00:23:57,800 --> 00:23:59,560 Speaker 1: For example, if you have a straw in new glass 448 00:23:59,560 --> 00:24:01,560 Speaker 1: of water, looks like the straw sort of broken in 449 00:24:01,640 --> 00:24:04,280 Speaker 1: half because the part of the light that's going through 450 00:24:04,280 --> 00:24:07,280 Speaker 1: the water gets bent slightly in a new directions. That's 451 00:24:07,280 --> 00:24:10,320 Speaker 1: what we call refraction, and that's tricky to understand for 452 00:24:10,480 --> 00:24:13,080 Speaker 1: like the path of an individual photon, but it's very 453 00:24:13,080 --> 00:24:15,960 Speaker 1: straightforward from like the mathematics of the wave equation. So 454 00:24:16,040 --> 00:24:19,680 Speaker 1: what's going on? Then? Why does lighter any wave change 455 00:24:20,000 --> 00:24:23,800 Speaker 1: direction when it changes the medium it's going in. So 456 00:24:23,800 --> 00:24:26,440 Speaker 1: when a wave travels through a medium, it's like wiggling 457 00:24:26,600 --> 00:24:31,159 Speaker 1: something right, and different kinds of medium wiggle in different ways. So, 458 00:24:31,160 --> 00:24:33,160 Speaker 1: for example, if you shout in the air and then 459 00:24:33,200 --> 00:24:36,399 Speaker 1: that sound wave hit water, part of it reflects and 460 00:24:36,440 --> 00:24:38,720 Speaker 1: part of it goes into the water and changes direction, 461 00:24:38,920 --> 00:24:42,200 Speaker 1: But it gets fundamentally transformed when it goes into the water. 462 00:24:42,359 --> 00:24:46,400 Speaker 1: Right now, it's wiggling water molecules instead of wiggling air molecules. 463 00:24:46,680 --> 00:24:48,840 Speaker 1: In order to balance all the frequencies at the surface 464 00:24:48,840 --> 00:24:50,919 Speaker 1: to make the math add up at the surface, so 465 00:24:50,960 --> 00:24:54,320 Speaker 1: everything is like making sense and being continuous. Those waves 466 00:24:54,359 --> 00:24:57,200 Speaker 1: sort of have to change direction in order to account 467 00:24:57,200 --> 00:24:59,359 Speaker 1: for the fact that it's like a new kind of wave. 468 00:25:00,119 --> 00:25:03,639 Speaker 1: That's the fundamental physics of like refraction of waves for light. 469 00:25:03,680 --> 00:25:05,280 Speaker 1: It's a little bit complicated if you want to think about, 470 00:25:05,280 --> 00:25:07,960 Speaker 1: like what happens to one photon when it hits the 471 00:25:07,960 --> 00:25:10,200 Speaker 1: surface of the water. How does it know how much 472 00:25:10,240 --> 00:25:13,439 Speaker 1: to bend right? And that's determined by the wave equation. 473 00:25:13,520 --> 00:25:16,960 Speaker 1: That's why it's fundamentally quantum mechanical. Two photons hitting a 474 00:25:17,000 --> 00:25:20,480 Speaker 1: surface might bend in slightly different directions, but a bunch 475 00:25:20,520 --> 00:25:23,119 Speaker 1: of photons hitting the surface sort of average out to 476 00:25:23,200 --> 00:25:25,800 Speaker 1: give you the answer you would expect from the wave equations. 477 00:25:26,200 --> 00:25:29,400 Speaker 1: But I guess what, like, what's happening to the individual photon, 478 00:25:29,800 --> 00:25:32,920 Speaker 1: how does it change direction? For example, you can't really 479 00:25:32,960 --> 00:25:36,040 Speaker 1: ask the question what happens to an individual photon unless 480 00:25:36,040 --> 00:25:38,920 Speaker 1: you're actually observing, unless you're seeing it. You can only 481 00:25:38,960 --> 00:25:42,040 Speaker 1: really think about photons as particles when you're observing them. 482 00:25:42,280 --> 00:25:44,480 Speaker 1: So you shoot a photon out, it hits the surface 483 00:25:44,520 --> 00:25:47,320 Speaker 1: of the water, then you detect it somewhere in the water, right, 484 00:25:47,400 --> 00:25:49,600 Speaker 1: and you want to know, like what happened at the 485 00:25:49,640 --> 00:25:52,160 Speaker 1: surface of the water. That's like going to the double 486 00:25:52,200 --> 00:25:55,640 Speaker 1: slit experiment and asking like which slit did the photon 487 00:25:55,760 --> 00:25:59,640 Speaker 1: go through? Really, the photon has many possible paths between 488 00:26:00,040 --> 00:26:02,639 Speaker 1: the source of the light and where you're detecting it, 489 00:26:02,920 --> 00:26:06,640 Speaker 1: and quantum mechanically speaking, it does all of them together. Right. 490 00:26:06,680 --> 00:26:09,080 Speaker 1: There's not a single story for what happened to that 491 00:26:09,160 --> 00:26:12,640 Speaker 1: individual photon, right, But I guess it's a little bit 492 00:26:12,680 --> 00:26:16,560 Speaker 1: different because to the photon, it didn't change mediums, right, 493 00:26:16,640 --> 00:26:20,000 Speaker 1: Like it didn't change how it was. The electromagnetic field 494 00:26:20,000 --> 00:26:23,080 Speaker 1: didn't change between outside the water and inside the water. Right. 495 00:26:23,119 --> 00:26:25,480 Speaker 1: To a photon is just going through the electromagnetic field. 496 00:26:25,680 --> 00:26:28,600 Speaker 1: The difference is that it's suddenly surrounded by a bunch 497 00:26:28,600 --> 00:26:32,560 Speaker 1: of water molecules, right, And so are you saying, like 498 00:26:32,600 --> 00:26:36,600 Speaker 1: all those water molecules basically act like little double slits. Yeah, 499 00:26:36,640 --> 00:26:39,879 Speaker 1: all those water molecules are like little interactions. How do 500 00:26:39,960 --> 00:26:43,840 Speaker 1: water molecules change the path of the wave. Well, remember 501 00:26:43,880 --> 00:26:47,200 Speaker 1: that the water molecules are charged particles, so they interact 502 00:26:47,320 --> 00:26:49,640 Speaker 1: with the photon field. You know. One way to think 503 00:26:49,680 --> 00:26:52,159 Speaker 1: about it is that like the photon is getting pulled 504 00:26:52,200 --> 00:26:54,879 Speaker 1: on by all those molecules. But you can't really have 505 00:26:54,960 --> 00:26:57,359 Speaker 1: like a single picture of the path of an individual 506 00:26:57,359 --> 00:27:00,480 Speaker 1: photon and say this one got bent in this particugular way. 507 00:27:00,560 --> 00:27:03,240 Speaker 1: There's lots of different possibilities for what might happen to 508 00:27:03,280 --> 00:27:05,840 Speaker 1: the photon when it goes through, and one photon will 509 00:27:05,840 --> 00:27:08,239 Speaker 1: go in one direction, another in the other direction. If 510 00:27:08,240 --> 00:27:11,399 Speaker 1: you average up over many many photons, millions of photons, 511 00:27:11,680 --> 00:27:14,040 Speaker 1: then you'll get this sort of average behavior you expect 512 00:27:14,400 --> 00:27:17,920 Speaker 1: from a classical wave. But for an individual particle, it's 513 00:27:17,960 --> 00:27:21,040 Speaker 1: a little bit random. Because I guess the photon from 514 00:27:21,119 --> 00:27:23,119 Speaker 1: its point of view, it's like it's going along. Suddenly 515 00:27:23,119 --> 00:27:26,320 Speaker 1: it sees a wall of water molecules, and some of 516 00:27:26,359 --> 00:27:28,600 Speaker 1: those molecules bounce it this way or bounce it that 517 00:27:28,640 --> 00:27:32,440 Speaker 1: way or right. Is that what you're saying, m Yeah, exactly. 518 00:27:32,520 --> 00:27:35,400 Speaker 1: And when you say bounce it you mean reflection. Yeah, 519 00:27:35,440 --> 00:27:38,280 Speaker 1: we mean interaction, which of course means like absorption and 520 00:27:38,400 --> 00:27:42,600 Speaker 1: re emission, and I guess the angle of that reflection 521 00:27:42,840 --> 00:27:45,720 Speaker 1: will change because the water molecules are you know, in 522 00:27:45,880 --> 00:27:49,119 Speaker 1: random pocisitions. And so you're saying the aggregate effect is 523 00:27:49,160 --> 00:27:53,800 Speaker 1: that it refracts light along a certain angle. M hmm, exactly. 524 00:27:54,119 --> 00:27:56,879 Speaker 1: It's the aggregate effect that's controlled by the wave equations. 525 00:27:57,160 --> 00:27:59,640 Speaker 1: It's maybe crisp is when you think about like reflection, 526 00:28:00,160 --> 00:28:02,400 Speaker 1: what happens when light hits a mirror, for example, Sure, 527 00:28:02,440 --> 00:28:04,720 Speaker 1: it gets absorbed by the atoms in the surface of 528 00:28:04,760 --> 00:28:08,160 Speaker 1: the mirror, but how do those atoms know what direction 529 00:28:08,280 --> 00:28:11,040 Speaker 1: to send the light? Out? Right? Light when it hits 530 00:28:11,040 --> 00:28:13,000 Speaker 1: the mirror doesn't just come off at any angle, comes 531 00:28:13,000 --> 00:28:15,320 Speaker 1: off at a very precise angle, like it bounces off 532 00:28:15,440 --> 00:28:19,160 Speaker 1: right following Snell's law. How do the atoms that absorbed 533 00:28:19,200 --> 00:28:22,480 Speaker 1: the photon know in what direction to send it? We 534 00:28:22,560 --> 00:28:25,560 Speaker 1: can't really answer that question from the particle point of view, 535 00:28:25,640 --> 00:28:28,000 Speaker 1: because you know, they don't really know. But there's a 536 00:28:28,000 --> 00:28:30,760 Speaker 1: lot of wave mechanics that are guiding what's happening to 537 00:28:30,920 --> 00:28:34,880 Speaker 1: the average photon. Because nobody's actually watching a single particle 538 00:28:34,960 --> 00:28:38,040 Speaker 1: absorbed that photon and re emit it. It's just like 539 00:28:38,080 --> 00:28:41,800 Speaker 1: an average process for many, many possible paths, and a 540 00:28:41,840 --> 00:28:45,920 Speaker 1: lot of those conflict and interfere, giving you overall the 541 00:28:45,920 --> 00:28:49,000 Speaker 1: photon being emitted in the right direction that's predicted sort 542 00:28:49,000 --> 00:28:51,920 Speaker 1: of by classical optics. Right, doesn't it all have to 543 00:28:52,000 --> 00:28:56,200 Speaker 1: do a lot with the crystals, right, and the order 544 00:28:56,280 --> 00:28:58,760 Speaker 1: of the things that you're shining a light on. Then 545 00:28:58,800 --> 00:29:00,880 Speaker 1: that's when you get something that can mirror, which bounces 546 00:29:00,960 --> 00:29:05,040 Speaker 1: things more neatly. Right, Mirrors do bounce things more neatly. 547 00:29:05,280 --> 00:29:08,600 Speaker 1: It has mostly to do with the conductivity properties of 548 00:29:08,640 --> 00:29:12,200 Speaker 1: the surface. Conductors are things that don't allow electric fields 549 00:29:12,280 --> 00:29:14,360 Speaker 1: very deep in them, have a bunch of electrons inside 550 00:29:14,400 --> 00:29:18,360 Speaker 1: them which rearrange themselves to like cancel out any electric field. 551 00:29:18,800 --> 00:29:21,280 Speaker 1: And so photons when they hit something that's like a mirror, 552 00:29:21,360 --> 00:29:23,880 Speaker 1: don't go very deep. They bounced right off the surface, 553 00:29:24,080 --> 00:29:26,600 Speaker 1: whereas things that are not mirrors, like your wall, which 554 00:29:26,640 --> 00:29:29,280 Speaker 1: is white which reflects a lot of light, doesn't act 555 00:29:29,280 --> 00:29:31,280 Speaker 1: like a mirror. Because the photons can get sort of 556 00:29:31,320 --> 00:29:34,960 Speaker 1: deeper in and interact with things further inside, and because 557 00:29:35,000 --> 00:29:38,120 Speaker 1: different photons will get different distances inside, they come out 558 00:29:38,160 --> 00:29:41,400 Speaker 1: a little bit scrambled. So images are, for example, scrambled 559 00:29:41,400 --> 00:29:44,240 Speaker 1: by a white wall, whereas they're not scrambled by a mirror, 560 00:29:44,640 --> 00:29:47,640 Speaker 1: because the mirror reflects everything basically from the very same depth, 561 00:29:47,680 --> 00:29:51,280 Speaker 1: which is right at the surface, right right, Well that's interesting, yeah, 562 00:29:51,280 --> 00:29:52,520 Speaker 1: but I mean it also has to do with the 563 00:29:52,560 --> 00:29:54,720 Speaker 1: surface sector, right, That's why you can polish things to 564 00:29:54,760 --> 00:29:57,560 Speaker 1: make them look shiny. Yeah, exactly, want a very flat surface. 565 00:29:57,800 --> 00:30:00,360 Speaker 1: So all the photons are bouncing off at the same instance, 566 00:30:00,800 --> 00:30:03,640 Speaker 1: and that's why conductors like silver or steel whatever make 567 00:30:03,720 --> 00:30:06,400 Speaker 1: good mirrors. All right, Well, I think that answers Matthew's 568 00:30:06,480 --> 00:30:10,360 Speaker 1: question what happens when photons hit stuff? The answer is 569 00:30:10,680 --> 00:30:15,440 Speaker 1: they die, Yeah, Daniel, I think that's our basic conclusion today. Yes, 570 00:30:15,480 --> 00:30:18,960 Speaker 1: every interaction is an absorption and a re emission, which 571 00:30:18,960 --> 00:30:23,360 Speaker 1: means the original photon is gone, baby gone. I mean, 572 00:30:23,760 --> 00:30:26,160 Speaker 1: it's we joke about it, but it's kind of true. Right, 573 00:30:26,200 --> 00:30:30,240 Speaker 1: like all light interactions reflection when something shining not shining 574 00:30:30,400 --> 00:30:34,440 Speaker 1: black white colors, you know, all that is uh in 575 00:30:34,560 --> 00:30:37,200 Speaker 1: every interaction. Every time light bounces off with something, it 576 00:30:37,360 --> 00:30:40,440 Speaker 1: dies and then it gets resurrected. I prefer to think 577 00:30:40,440 --> 00:30:43,160 Speaker 1: of it, it's like having children, because the original photon 578 00:30:43,280 --> 00:30:46,640 Speaker 1: is influencing the new photons certainly, man, And now you 579 00:30:46,680 --> 00:30:51,560 Speaker 1: get into whether photons are house photons reproduced? Is that 580 00:30:51,560 --> 00:30:59,840 Speaker 1: what you're I think that's gets into philosophical biological podcast right. 581 00:31:00,520 --> 00:31:03,920 Speaker 1: We only allow certain kinds of baseless philosophy on this show. 582 00:31:04,000 --> 00:31:10,800 Speaker 1: That's where we have standards here, only fantastic discussions here. Well, 583 00:31:10,840 --> 00:31:14,240 Speaker 1: thank you very much Matthew for that really intriguing question. 584 00:31:14,280 --> 00:31:16,720 Speaker 1: All right. Our next question comes from Tim and it 585 00:31:16,800 --> 00:31:20,520 Speaker 1: has to do with stars. Hey, Daniel and Core Hey, 586 00:31:21,760 --> 00:31:24,920 Speaker 1: I had a question. Is there such a thing as 587 00:31:24,960 --> 00:31:28,800 Speaker 1: a star that is so big or so bright that 588 00:31:29,120 --> 00:31:34,160 Speaker 1: it would actually affect the daytime nighttime cycles of planets 589 00:31:34,280 --> 00:31:37,320 Speaker 1: in a nearby solar system. I'm not talking about like 590 00:31:37,320 --> 00:31:41,400 Speaker 1: a binary solar system, talking about a star that is 591 00:31:41,960 --> 00:31:45,920 Speaker 1: in a neighboring system. Just listen to your podcasts about 592 00:31:46,200 --> 00:31:49,280 Speaker 1: twinkling stars and that made me thinking about it. Thanks 593 00:31:49,280 --> 00:31:52,480 Speaker 1: for the answers, because I know you'll have them. Well, 594 00:31:52,480 --> 00:31:54,680 Speaker 1: thank you Tim for that question and the faith that 595 00:31:54,720 --> 00:31:57,680 Speaker 1: you have that we will have answers. I come in 596 00:31:58,080 --> 00:32:01,400 Speaker 1: every time having the same confidence. Did you do well? 597 00:32:01,400 --> 00:32:03,800 Speaker 1: We'll definitely have something to say, even if we can't 598 00:32:03,840 --> 00:32:07,480 Speaker 1: answer the question definitively that's right, that's right. Anything techniquely 599 00:32:07,480 --> 00:32:09,840 Speaker 1: counts as an answer. I learned with my kids. When 600 00:32:09,920 --> 00:32:13,840 Speaker 1: questions hit the podcast, they die. That's right, to get absorbed, 601 00:32:14,520 --> 00:32:17,640 Speaker 1: and then we burth and back out into your ear. 602 00:32:18,040 --> 00:32:24,040 Speaker 1: We admit something. All right. Well, Tim's question is that 603 00:32:24,440 --> 00:32:27,920 Speaker 1: is it possible for a light from a different solar 604 00:32:27,960 --> 00:32:31,480 Speaker 1: system to affect the feeling of day and night in 605 00:32:31,760 --> 00:32:36,040 Speaker 1: a planet in another solar system? Right? That's the basic question. Yeah, Basically, 606 00:32:36,200 --> 00:32:39,440 Speaker 1: can stars change the day night pattern? Like? Could stars 607 00:32:39,520 --> 00:32:42,960 Speaker 1: be bright enough that they cause shadows? For example, I've 608 00:32:42,960 --> 00:32:45,000 Speaker 1: been out at night looking at but the stars and 609 00:32:45,000 --> 00:32:47,120 Speaker 1: then checking out behind me to see, like, am I 610 00:32:47,160 --> 00:32:50,560 Speaker 1: casting a star shadow? Star shadow? Sounds like a good 611 00:32:50,720 --> 00:32:54,080 Speaker 1: gamer tag. But of course, as you look up at 612 00:32:54,080 --> 00:32:56,760 Speaker 1: the night sky, those stars are obvious to your eyes, 613 00:32:56,960 --> 00:33:00,000 Speaker 1: but they're not bright enough to make the night sky 614 00:33:00,080 --> 00:33:03,160 Speaker 1: bright right, to make it feel like it's daytime? Well, 615 00:33:03,160 --> 00:33:06,280 Speaker 1: technically they do cast. You do cast a star shadow, right, 616 00:33:06,360 --> 00:33:09,680 Speaker 1: or a shadow star right? Like the technically, yeah, you 617 00:33:09,720 --> 00:33:13,560 Speaker 1: are blocking light from stars and preventing something behind you 618 00:33:13,680 --> 00:33:16,520 Speaker 1: from getting that light. Yeah, And it's fundamentally the same 619 00:33:16,560 --> 00:33:19,800 Speaker 1: process as getting a shadow from our sun. It's just 620 00:33:19,880 --> 00:33:22,600 Speaker 1: that our sun is closer, right, and so it's brighter, 621 00:33:23,000 --> 00:33:26,400 Speaker 1: so you notice it much more because it does dominate 622 00:33:26,480 --> 00:33:28,480 Speaker 1: the brightness of our planet. And the thing I love 623 00:33:28,480 --> 00:33:30,640 Speaker 1: about Tim's question, he says he's wondering about these two 624 00:33:30,640 --> 00:33:34,440 Speaker 1: different categories, our sun and the distant stars, and wondering 625 00:33:34,480 --> 00:33:37,120 Speaker 1: if there's something that bridges them. Is it's possible to 626 00:33:37,120 --> 00:33:40,080 Speaker 1: have something in between other stars that are close enough 627 00:33:40,160 --> 00:33:42,400 Speaker 1: to be sort of like part of our day night cycle. 628 00:33:42,600 --> 00:33:44,400 Speaker 1: Really cool way to think about it. I guess maybe 629 00:33:44,440 --> 00:33:46,880 Speaker 1: the question is like, how close can two solar systems 630 00:33:46,920 --> 00:33:50,400 Speaker 1: get so that one sun actually changes the day night 631 00:33:50,560 --> 00:33:53,920 Speaker 1: time feeling of another solar system? Yeah? Maybe Tim's working 632 00:33:53,920 --> 00:33:55,760 Speaker 1: on a science fiction novel, and this is an important 633 00:33:55,760 --> 00:33:57,880 Speaker 1: part of the plot, Right, isn't everybody working on a 634 00:33:57,920 --> 00:34:00,560 Speaker 1: science fic novel? I don't know. I feel like science 635 00:34:00,560 --> 00:34:02,920 Speaker 1: fiction gets absorbed by the reader and then not always 636 00:34:02,960 --> 00:34:06,120 Speaker 1: re emitted as a new novel. Right. Sometimes science fiction 637 00:34:06,160 --> 00:34:11,680 Speaker 1: novels just die. I see, they die in the reader's brain. 638 00:34:11,880 --> 00:34:14,120 Speaker 1: Maybe the reader just goes to an excited state of 639 00:34:14,200 --> 00:34:17,480 Speaker 1: knowledge and enlightenment. Oh there you go, transforms that energy 640 00:34:17,480 --> 00:34:22,040 Speaker 1: into you know, their their own work, their own imagination. 641 00:34:22,560 --> 00:34:26,160 Speaker 1: But anyway, here we are not answering Tim's question once again, Yes, 642 00:34:26,280 --> 00:34:28,560 Speaker 1: but we are trying to hear and um So, I 643 00:34:28,600 --> 00:34:31,479 Speaker 1: guess the question is how far canto solar systems get 644 00:34:31,719 --> 00:34:35,279 Speaker 1: before maybe they're not two different solar systems. I wonder 645 00:34:35,280 --> 00:34:37,239 Speaker 1: if that's kind of part of the question. Yeah, because 646 00:34:37,239 --> 00:34:39,960 Speaker 1: he specifically ruled out like a binary solar system where 647 00:34:39,960 --> 00:34:42,520 Speaker 1: you have two stars. It's a really interesting question and 648 00:34:42,560 --> 00:34:44,919 Speaker 1: there's a couple of different parameters we can play with here. 649 00:34:45,320 --> 00:34:48,799 Speaker 1: One is where you are in the galaxy, which really 650 00:34:48,840 --> 00:34:52,960 Speaker 1: determines how far apart stars are, and also how big 651 00:34:53,000 --> 00:34:56,400 Speaker 1: the stars are, because there's a huge variation in the 652 00:34:56,440 --> 00:34:59,879 Speaker 1: brightness and the size of stars. Right there are big ones, 653 00:35:00,160 --> 00:35:04,080 Speaker 1: small ones, and out in our neighborhood of the galaxy, 654 00:35:04,120 --> 00:35:06,400 Speaker 1: we're sort of like halfway out from the center of 655 00:35:06,400 --> 00:35:09,640 Speaker 1: the galaxy. Things are not very tightly packed. We're sort 656 00:35:09,640 --> 00:35:11,960 Speaker 1: of like in the suburbs of the galaxy. Like the 657 00:35:12,000 --> 00:35:15,920 Speaker 1: closest star to Earth is about four light years away. 658 00:35:16,400 --> 00:35:19,920 Speaker 1: That's really really far away. And remember that the brightness 659 00:35:19,920 --> 00:35:22,680 Speaker 1: of a star gets dimmer as you get further away, 660 00:35:22,680 --> 00:35:25,719 Speaker 1: and it gets dimmer by that distance squared, So if 661 00:35:25,760 --> 00:35:29,200 Speaker 1: you're ten times further away, a star is a hundred 662 00:35:29,280 --> 00:35:32,920 Speaker 1: times dimmer. If you're a thousand times further away, then 663 00:35:32,960 --> 00:35:37,240 Speaker 1: it's a million times dimmer. So that mathematics really works 664 00:35:37,280 --> 00:35:40,640 Speaker 1: against the distant stars. It's why the Sun really dominates 665 00:35:40,840 --> 00:35:43,560 Speaker 1: our experience. Yeah, and it's why if we were ten 666 00:35:43,600 --> 00:35:46,680 Speaker 1: times closer to the Sun, we would feel it's heat 667 00:35:46,760 --> 00:35:50,080 Speaker 1: a million times more, right, we need toast. Yeah, and 668 00:35:50,080 --> 00:35:53,120 Speaker 1: in our neighborhood the stars are pretty diffused, but if 669 00:35:53,120 --> 00:35:55,640 Speaker 1: you go to the center of the galaxy, things are 670 00:35:55,960 --> 00:35:59,000 Speaker 1: much more cozy. Right in the center of the galaxy, 671 00:35:59,040 --> 00:36:01,879 Speaker 1: it's not uncommon to have stars that are less than 672 00:36:01,880 --> 00:36:04,400 Speaker 1: a light year apart, or even less than a tenth 673 00:36:04,480 --> 00:36:07,800 Speaker 1: of a light year apart, And so those stars benefit 674 00:36:07,920 --> 00:36:10,160 Speaker 1: from that short distance. They get the same math, but 675 00:36:10,239 --> 00:36:13,600 Speaker 1: working in their favor to boost their brightness. You're ten 676 00:36:13,640 --> 00:36:16,879 Speaker 1: times closer, now you're a hundred times brighter. To give 677 00:36:16,920 --> 00:36:18,759 Speaker 1: you a sense of like what that means, if we 678 00:36:18,840 --> 00:36:21,560 Speaker 1: had another star as bright as our sun that was 679 00:36:21,600 --> 00:36:24,200 Speaker 1: like half a light year away, we would see it 680 00:36:24,320 --> 00:36:26,759 Speaker 1: during the daytime. It would be like bright enough in 681 00:36:26,800 --> 00:36:29,560 Speaker 1: our sky to see during the daytime, be about as 682 00:36:29,600 --> 00:36:32,520 Speaker 1: bright as venuses, which you can see during the daytime. 683 00:36:32,640 --> 00:36:35,440 Speaker 1: So like we would look up into the day sky 684 00:36:35,600 --> 00:36:38,040 Speaker 1: and maybe among the clouds you would see a little 685 00:36:38,080 --> 00:36:41,040 Speaker 1: pinpoint of light. Yeah, you'd see a pinpoint. It wouldn't 686 00:36:41,120 --> 00:36:43,319 Speaker 1: change the day night cycle, right, you could see it 687 00:36:43,400 --> 00:36:44,959 Speaker 1: during the day of the way you can see the moon, 688 00:36:45,480 --> 00:36:48,520 Speaker 1: but doesn't mean that the night would feel like the day, 689 00:36:48,640 --> 00:36:50,879 Speaker 1: but it would be something that's visible. So you could 690 00:36:50,920 --> 00:36:53,640 Speaker 1: see another sun that was like point forward light years away, 691 00:36:54,000 --> 00:36:56,200 Speaker 1: you know, if it was even closer than it would 692 00:36:56,239 --> 00:36:58,520 Speaker 1: be even brighter and in the center of the galaxy. 693 00:36:58,640 --> 00:37:01,520 Speaker 1: That does happen stars very close together, But I guess 694 00:37:01,560 --> 00:37:05,040 Speaker 1: at what point does it become part of a binary system? 695 00:37:05,080 --> 00:37:07,920 Speaker 1: You know, like how close can two stars get without 696 00:37:07,960 --> 00:37:12,680 Speaker 1: them basically being the same in affecting each other gravitationally, 697 00:37:12,760 --> 00:37:15,720 Speaker 1: so that they become one big solar system. Well, stars 698 00:37:15,719 --> 00:37:18,480 Speaker 1: are always going to pull on each other gravitationally, right, 699 00:37:18,600 --> 00:37:21,319 Speaker 1: we are getting pulled on by our neighboring stars even 700 00:37:21,320 --> 00:37:24,200 Speaker 1: though they are four light years away, and our galaxy 701 00:37:24,280 --> 00:37:26,600 Speaker 1: is getting pulled on by the neighboring galaxy even though 702 00:37:26,600 --> 00:37:29,680 Speaker 1: it's millions of light years away. So it's just sort 703 00:37:29,680 --> 00:37:33,360 Speaker 1: of like a cosmic web of gravitational interactions. And in 704 00:37:33,360 --> 00:37:35,560 Speaker 1: the center of the galaxy, these stars are all tugging 705 00:37:35,600 --> 00:37:38,400 Speaker 1: on each other, but they're not like in stable orbits 706 00:37:38,480 --> 00:37:40,800 Speaker 1: around each other. I think for a binary star system 707 00:37:41,040 --> 00:37:43,960 Speaker 1: you want them to be like gravitationally captured by each other. 708 00:37:44,320 --> 00:37:46,399 Speaker 1: But it's more like a mosh pit than a bunch 709 00:37:46,400 --> 00:37:48,480 Speaker 1: of dancing couples in the center of the galaxy. It's 710 00:37:48,520 --> 00:37:51,000 Speaker 1: kind of crazy down there. So I guess if you're 711 00:37:51,040 --> 00:37:53,759 Speaker 1: close to the center of the galaxy, uh, there's not 712 00:37:53,800 --> 00:37:56,680 Speaker 1: just probably one star that's have a light year a way. 713 00:37:56,719 --> 00:37:59,239 Speaker 1: There's a Brazilian stars that are light your way. So 714 00:37:59,640 --> 00:38:02,160 Speaker 1: if our solar system was and near the center of 715 00:38:02,200 --> 00:38:04,200 Speaker 1: the galaxy, we would look up at the day sky 716 00:38:04,480 --> 00:38:07,279 Speaker 1: and it would be filled with pinpoints, right, maybe just 717 00:38:07,560 --> 00:38:10,440 Speaker 1: a huge cloud that it would all just kind of 718 00:38:10,440 --> 00:38:14,440 Speaker 1: be super bright everywhere. Yeah, exactly. And it wouldn't be 719 00:38:14,560 --> 00:38:18,120 Speaker 1: unreasonable that your night sky might have a very very 720 00:38:18,200 --> 00:38:20,759 Speaker 1: bright star in it. You might have a neighbor which 721 00:38:20,800 --> 00:38:23,120 Speaker 1: is pretty close and just the same way, when you're 722 00:38:23,120 --> 00:38:25,319 Speaker 1: trying to sleep, if your neighbor has like floodlights on 723 00:38:25,400 --> 00:38:27,480 Speaker 1: in their house, it can go through your windows and 724 00:38:27,560 --> 00:38:30,239 Speaker 1: disturb your sleep. Near the center of the galaxy, you 725 00:38:30,360 --> 00:38:33,200 Speaker 1: might have a neighboring star that's bright enough to disturb 726 00:38:33,280 --> 00:38:36,640 Speaker 1: your night, especially if that neighboring star is not like 727 00:38:36,680 --> 00:38:39,320 Speaker 1: the Sun, if it's one of the big monster stars. 728 00:38:39,880 --> 00:38:43,680 Speaker 1: Because stars have a huge variation in their brightness. You know, 729 00:38:43,800 --> 00:38:46,319 Speaker 1: our sun is britty bright, but there are many more 730 00:38:46,400 --> 00:38:49,440 Speaker 1: stars out there that are much much brighter than our sun. Right, 731 00:38:49,480 --> 00:38:52,200 Speaker 1: I guess it's all relative, right, Like what what we 732 00:38:52,280 --> 00:38:56,400 Speaker 1: consider daytime here might be equivalent to nighttime on a 733 00:38:56,480 --> 00:38:58,719 Speaker 1: planet near the center of the galaxy, right, just from 734 00:38:58,760 --> 00:39:02,359 Speaker 1: all the life from all the by stars. Yeah, potentially, Yeah, 735 00:39:02,440 --> 00:39:04,799 Speaker 1: that's true exactly, And just to give you a sense 736 00:39:04,800 --> 00:39:06,640 Speaker 1: of the range, you know, like in our night sky, 737 00:39:07,040 --> 00:39:09,240 Speaker 1: there are other stars we can see that are much brighter. 738 00:39:09,280 --> 00:39:11,600 Speaker 1: Like Serious is a star in our sky, and it's 739 00:39:11,640 --> 00:39:14,319 Speaker 1: twenty five times as bright as the Sun. If you're 740 00:39:14,320 --> 00:39:16,520 Speaker 1: at the same distance from Serious as you were from 741 00:39:16,520 --> 00:39:19,600 Speaker 1: the Sun, it would be twenty five times as bright. 742 00:39:20,160 --> 00:39:22,040 Speaker 1: But that's just like a little step up. There are 743 00:39:22,040 --> 00:39:25,640 Speaker 1: other stars, like the biggest stars in our galaxy, one 744 00:39:25,719 --> 00:39:29,840 Speaker 1: is called Eta Carina, that are like two million times 745 00:39:29,960 --> 00:39:33,920 Speaker 1: as bright as the Sun two million, and so any 746 00:39:33,960 --> 00:39:36,839 Speaker 1: star in the neighborhood of Eta Carina is basically going 747 00:39:36,880 --> 00:39:40,080 Speaker 1: to be bright all night long. Yeah, And I guess 748 00:39:40,120 --> 00:39:42,799 Speaker 1: it also opens the possibility that like that, like maybe 749 00:39:42,800 --> 00:39:46,760 Speaker 1: if you're a planet orbiting a dim star, like maybe 750 00:39:46,800 --> 00:39:50,080 Speaker 1: like a brown dwarf or something that's just kind of simmering, 751 00:39:50,080 --> 00:39:53,040 Speaker 1: they're not really shining as bright as our sun. Then 752 00:39:53,239 --> 00:39:56,040 Speaker 1: for you, if you are near the center of the galaxy, 753 00:39:56,160 --> 00:39:59,960 Speaker 1: then really your son maybe doesn't even influence the day 754 00:40:00,080 --> 00:40:02,719 Speaker 1: a night cycle, right, Like maybe for you in that 755 00:40:02,760 --> 00:40:06,520 Speaker 1: Solar system, day and night is when your planet's facing 756 00:40:06,560 --> 00:40:08,640 Speaker 1: the center of the galaxy or not facing the center 757 00:40:08,640 --> 00:40:11,480 Speaker 1: of the gap, right, Like a day could be like 758 00:40:11,520 --> 00:40:14,279 Speaker 1: a whole year. Yeah, and the darkest times could be 759 00:40:14,320 --> 00:40:16,880 Speaker 1: when your son who clips is the other bright neighbor, 760 00:40:16,960 --> 00:40:19,680 Speaker 1: so you can have like a star star eclipse. Wow. Yeah, 761 00:40:19,800 --> 00:40:24,840 Speaker 1: who said science fiction dies? On this podcast, we're not 762 00:40:24,920 --> 00:40:27,400 Speaker 1: just absorbing science fiction here. We are emitting it in 763 00:40:27,440 --> 00:40:32,160 Speaker 1: real time. We are creating it. You're redirecting it. We 764 00:40:32,200 --> 00:40:34,839 Speaker 1: are reflecting these ideas back again. We want to hear 765 00:40:34,840 --> 00:40:36,600 Speaker 1: this story. Send us the draft of your novel when 766 00:40:36,600 --> 00:40:39,920 Speaker 1: you finished it. Yeah, but make sure we sign an 767 00:40:39,960 --> 00:40:43,720 Speaker 1: NDA here. I wouldn't trust us not to copy your ideas. Copy. 768 00:40:43,760 --> 00:40:47,560 Speaker 1: We're collaborators, we're co authors, we're here workshopping it live man. 769 00:40:47,960 --> 00:40:50,760 Speaker 1: All right, well, thank you Dann for that awesome question. Um, 770 00:40:50,960 --> 00:40:53,960 Speaker 1: I guess the answer is yes, there could be stars 771 00:40:54,000 --> 00:40:57,640 Speaker 1: so bright that they do affect the night day time cycle. 772 00:40:57,719 --> 00:41:00,200 Speaker 1: And in fact, if you're closer far away from the 773 00:41:00,200 --> 00:41:02,960 Speaker 1: center of the galaxy, it might make an bigger or 774 00:41:03,000 --> 00:41:05,839 Speaker 1: smaller difference. Yeah, the whole definition of day and night 775 00:41:05,880 --> 00:41:08,120 Speaker 1: would be really different, and it would lead to really 776 00:41:08,160 --> 00:41:11,360 Speaker 1: complicated patterns of life on that planet, which could be 777 00:41:11,360 --> 00:41:14,520 Speaker 1: really fun to explore in Tim's future debut science fiction novel, 778 00:41:14,640 --> 00:41:20,879 Speaker 1: Tim Jorgan Daniels new debut. Right, yes, of course, in fact, 779 00:41:20,920 --> 00:41:22,920 Speaker 1: you did he go first on the author list. I 780 00:41:22,920 --> 00:41:27,960 Speaker 1: don't know. We'll take that question off the air. All right, 781 00:41:28,000 --> 00:41:30,799 Speaker 1: let's get into our last question here about black holes 782 00:41:30,840 --> 00:41:34,040 Speaker 1: that are maybe made out of dark matter. We'll jump 783 00:41:34,120 --> 00:41:37,000 Speaker 1: right into that hole, but first let's take another quick break. 784 00:41:50,040 --> 00:41:53,560 Speaker 1: All right, we're answering listener questions and also stealing their ideas. 785 00:41:54,640 --> 00:41:59,640 Speaker 1: Apparently we're interacting with them, and we're interacted. I see, 786 00:42:01,320 --> 00:42:04,080 Speaker 1: that's right. The universe is not a criminal it's just 787 00:42:04,280 --> 00:42:08,560 Speaker 1: very interactive. That's right. The podcast host Field is interacting 788 00:42:08,600 --> 00:42:10,960 Speaker 1: with the podcast listener Field. Right, there's a couple and 789 00:42:10,960 --> 00:42:13,080 Speaker 1: there's a charge there. I can feel it. Yes, I 790 00:42:13,120 --> 00:42:16,439 Speaker 1: didn't still any classified documents. I just interacted with them 791 00:42:16,480 --> 00:42:21,040 Speaker 1: in my private home. Let's hope we don't get charged officially. Alright. 792 00:42:21,040 --> 00:42:24,000 Speaker 1: Our last question here comes from Matteo's and it's about 793 00:42:24,080 --> 00:42:27,640 Speaker 1: black holes. Hello, Daniel and Jorge, this is Mats from Poland. 794 00:42:28,000 --> 00:42:30,439 Speaker 1: I was wondering about the possibility of having a black 795 00:42:30,440 --> 00:42:33,719 Speaker 1: hole made entirely from the dark matter. I understand that 796 00:42:33,800 --> 00:42:36,440 Speaker 1: it's unlikely to happen because of the dark matter properties, 797 00:42:36,719 --> 00:42:39,640 Speaker 1: but I was wondering how could we detect one if 798 00:42:39,640 --> 00:42:42,160 Speaker 1: we can measure the black holes electric charge. Would a 799 00:42:42,239 --> 00:42:45,240 Speaker 1: zero charge mean that there is no normal matter inside? 800 00:42:45,640 --> 00:42:47,360 Speaker 1: How likely would it be for a black hole to 801 00:42:47,400 --> 00:42:50,960 Speaker 1: have zero electric charge? This also has led me to 802 00:42:51,120 --> 00:42:53,960 Speaker 1: some more general questions. Is the total electric charge in 803 00:42:53,960 --> 00:42:57,000 Speaker 1: the universe equal to zero? How about on galaxy or 804 00:42:57,040 --> 00:43:00,600 Speaker 1: planet level? I'm eager to hear your answers to my questions. 805 00:43:00,680 --> 00:43:02,719 Speaker 1: Thanks a lot for your great work with the podcast. 806 00:43:03,120 --> 00:43:05,560 Speaker 1: All right, thank you Matteos for that great question, and 807 00:43:05,600 --> 00:43:10,600 Speaker 1: it came to us free of charge, as all questions do. Now, 808 00:43:10,640 --> 00:43:13,440 Speaker 1: this is an interesting question he's asking. First of all, well, 809 00:43:13,480 --> 00:43:16,759 Speaker 1: he's asking several questions, but the first one was what 810 00:43:16,840 --> 00:43:21,719 Speaker 1: would happen if a black hole was made entirely out 811 00:43:21,719 --> 00:43:24,279 Speaker 1: of dark matter? He said, you know, he caveats that 812 00:43:24,400 --> 00:43:27,399 Speaker 1: it's unlike, he knows it's unlikely to happen. But what 813 00:43:27,480 --> 00:43:30,120 Speaker 1: if you made a black hole with dark matter? Would 814 00:43:30,120 --> 00:43:32,200 Speaker 1: it be different? Could? Could you tell the difference between 815 00:43:32,200 --> 00:43:34,759 Speaker 1: a regular black hole? Yeah? And even suggests a way 816 00:43:34,800 --> 00:43:38,000 Speaker 1: of maybe distinguishing dark matter black holes from a normal 817 00:43:38,040 --> 00:43:40,759 Speaker 1: matter black holes, which I thought was pretty clever. He's 818 00:43:40,760 --> 00:43:43,200 Speaker 1: thinking like a scientist. He's like, if this were to happen, 819 00:43:43,520 --> 00:43:46,920 Speaker 1: if I basically speculate about this, can this help me 820 00:43:46,960 --> 00:43:49,160 Speaker 1: write a ground Yeah? And so there's a bunch of 821 00:43:49,160 --> 00:43:52,360 Speaker 1: stuff going on here. First is the idea of what's 822 00:43:52,400 --> 00:43:54,600 Speaker 1: in a black hole? What can you make a black 823 00:43:54,640 --> 00:43:57,359 Speaker 1: hole out of? And you know, we think that black 824 00:43:57,360 --> 00:43:59,719 Speaker 1: holes can eat anything. They can eat normal matter, they 825 00:43:59,719 --> 00:44:02,480 Speaker 1: can eat dark matter, they can eat other black holes, 826 00:44:02,840 --> 00:44:05,520 Speaker 1: they can eat basically anything and grow because the curvature 827 00:44:05,560 --> 00:44:09,000 Speaker 1: space is determined not just by mass but by anything 828 00:44:09,040 --> 00:44:12,840 Speaker 1: with energy. That's what general relativity tells us. So black 829 00:44:12,840 --> 00:44:15,000 Speaker 1: holes can basically eat anything. You can make them out 830 00:44:15,040 --> 00:44:17,560 Speaker 1: of normal stuff or dark matter. But we think that 831 00:44:17,640 --> 00:44:21,319 Speaker 1: most black holes are probably dominated by normal matter because 832 00:44:21,360 --> 00:44:25,960 Speaker 1: it's harder for dark matter to fall into black holes. Mostly, 833 00:44:25,960 --> 00:44:29,440 Speaker 1: we think dark matter swirls around in big clouds, doesn't 834 00:44:29,440 --> 00:44:32,799 Speaker 1: clump together and fall into black holes as often as 835 00:44:32,920 --> 00:44:35,439 Speaker 1: normal matter. Right, because it's harder to make a black 836 00:44:35,440 --> 00:44:38,360 Speaker 1: hole out of dark matter, I think Matteo's kind of 837 00:44:38,400 --> 00:44:42,840 Speaker 1: acknowledged that they're harder to make and therefore less likely 838 00:44:42,880 --> 00:44:45,920 Speaker 1: to happen in the universe. But the basic answer is 839 00:44:45,920 --> 00:44:48,000 Speaker 1: that you can make a black hole out of dark matter. Like, 840 00:44:48,040 --> 00:44:51,040 Speaker 1: if you can somehow take dark matter squeeze it down 841 00:44:51,080 --> 00:44:53,640 Speaker 1: to a small enough radius, it would form a black hole. 842 00:44:53,680 --> 00:44:56,560 Speaker 1: In principle, absolutely yes, it would. And the reason that 843 00:44:56,640 --> 00:44:59,560 Speaker 1: it's harder to squeeze dark matter down is that we 844 00:44:59,600 --> 00:45:03,080 Speaker 1: don't think dark matter feels any other forces other than gravity, 845 00:45:03,360 --> 00:45:05,840 Speaker 1: so you can't push on it, for example, to compact. 846 00:45:05,960 --> 00:45:09,200 Speaker 1: It doesn't stick to itself, and that means it's hard 847 00:45:09,200 --> 00:45:11,840 Speaker 1: for it to give up angular momentum if it's spinning 848 00:45:11,880 --> 00:45:14,240 Speaker 1: around a black hole in the accretion disk, for example, 849 00:45:14,520 --> 00:45:16,719 Speaker 1: why do things fall into the black hole and not 850 00:45:16,840 --> 00:45:19,160 Speaker 1: just spin around them forever. They do that because they 851 00:45:19,200 --> 00:45:21,799 Speaker 1: lose angular momentum, They bump into something else in the 852 00:45:21,800 --> 00:45:25,080 Speaker 1: acreation disc and then head towards the black hole. Dark matter, 853 00:45:25,080 --> 00:45:27,600 Speaker 1: because it doesn't feel those forces we think, just passes 854 00:45:27,719 --> 00:45:31,080 Speaker 1: right through itself, doesn't bump into anything, doesn't stick together 855 00:45:31,120 --> 00:45:33,640 Speaker 1: into big blobs and fall into the black hole. But 856 00:45:33,760 --> 00:45:36,160 Speaker 1: it is possible if you somehow got a bunch of 857 00:45:36,200 --> 00:45:38,680 Speaker 1: dark matter together, it would make a black hole. Right, 858 00:45:38,760 --> 00:45:41,360 Speaker 1: And like also given enough time, right, Like, if you 859 00:45:41,440 --> 00:45:44,520 Speaker 1: have a blob of dark matter out in space, eventually 860 00:45:45,080 --> 00:45:47,640 Speaker 1: maybe in trillions of years, and it will all collapse 861 00:45:47,880 --> 00:45:51,759 Speaker 1: into a black hole. Right, that's right, Because rotation is acceleration, 862 00:45:51,800 --> 00:45:55,359 Speaker 1: which means it's giving off gravitational waves. So even something 863 00:45:55,360 --> 00:45:59,279 Speaker 1: that feels nothing else but gravity will eventually lose its 864 00:45:59,400 --> 00:46:02,400 Speaker 1: orbit because it's giving off energy out into the universe 865 00:46:02,440 --> 00:46:05,560 Speaker 1: and it will fall in. So, yes, eventually dark matter 866 00:46:05,640 --> 00:46:08,279 Speaker 1: will fall into a black hole, right, isn't there? I 867 00:46:08,320 --> 00:46:10,160 Speaker 1: mean there's a lot of dark matter out there in 868 00:46:10,200 --> 00:46:13,520 Speaker 1: the universe, a lot more than regular matter, and the 869 00:46:13,560 --> 00:46:16,120 Speaker 1: universe is pretty old, isn't it possible that at this 870 00:46:16,200 --> 00:46:19,000 Speaker 1: point some dark matter may have fallen and created a 871 00:46:19,040 --> 00:46:21,480 Speaker 1: dark matter black hole. It's almost certainly the case that 872 00:46:21,560 --> 00:46:24,799 Speaker 1: every black hole contains some dark matter. While a big 873 00:46:24,800 --> 00:46:26,880 Speaker 1: cloud is hard to collapse into a black hole, if 874 00:46:26,880 --> 00:46:29,160 Speaker 1: you have an existing black hole and a dark amoutter 875 00:46:29,160 --> 00:46:31,120 Speaker 1: of particle just like heads towards it, it's just going 876 00:46:31,200 --> 00:46:34,440 Speaker 1: to fall in. There's no like special protection. So every 877 00:46:34,440 --> 00:46:37,759 Speaker 1: black hole probably contains some dark matter. He's asking about, 878 00:46:37,800 --> 00:46:39,680 Speaker 1: like if it's possible to have a black hole that's 879 00:46:39,840 --> 00:46:43,680 Speaker 1: only dark matter, right, So imagine some big blob of 880 00:46:43,760 --> 00:46:47,200 Speaker 1: dark matter that's gotten separated from normal matter, which could happen, 881 00:46:47,480 --> 00:46:50,879 Speaker 1: right like the Bullet cluster collision stripped dark matter from 882 00:46:50,920 --> 00:46:53,200 Speaker 1: the normal matter in those galaxies, and of these big 883 00:46:53,400 --> 00:46:57,200 Speaker 1: vast clouds of dark matter basically all by themselves, wait 884 00:46:57,320 --> 00:47:00,719 Speaker 1: long enough, and that would collapse into a hole. Right. 885 00:47:00,760 --> 00:47:02,960 Speaker 1: He's asking, like, I think you're saying that, you know, 886 00:47:03,040 --> 00:47:06,600 Speaker 1: most black holes are like milk chocolate, you know, maybe 887 00:47:07,440 --> 00:47:11,080 Speaker 1: dark chocolate. But he's asking, can you have a dark 888 00:47:11,160 --> 00:47:14,280 Speaker 1: chocolate bark? Can you have a black hole made entirely 889 00:47:14,320 --> 00:47:16,960 Speaker 1: out of dark matter, and the answer is yes, right, 890 00:47:17,080 --> 00:47:19,560 Speaker 1: that can happen. The answer is yes, that can happen. 891 00:47:20,000 --> 00:47:21,680 Speaker 1: And then we have the question of like, how could 892 00:47:21,719 --> 00:47:23,960 Speaker 1: you tell? And now we run up against the problem, 893 00:47:24,000 --> 00:47:26,200 Speaker 1: which is that we can't know very much about what's 894 00:47:26,239 --> 00:47:29,000 Speaker 1: going on inside the black hole. The no hair theorem 895 00:47:29,000 --> 00:47:30,960 Speaker 1: tells us we can know the mass of the black hole, 896 00:47:31,000 --> 00:47:33,480 Speaker 1: basically how much stuff is in it. We can know 897 00:47:33,520 --> 00:47:36,600 Speaker 1: whether it's spinning, and we can know it's electric charge. 898 00:47:37,200 --> 00:47:39,799 Speaker 1: And that's the key that Mattheos is focusing on to 899 00:47:39,880 --> 00:47:41,560 Speaker 1: tell us whether or not the black hole is built 900 00:47:41,560 --> 00:47:44,359 Speaker 1: from dark matter or normal matter. Because if you take 901 00:47:44,360 --> 00:47:46,799 Speaker 1: a black hole and you throw electrons into it, you 902 00:47:46,840 --> 00:47:49,839 Speaker 1: can't tell what happens to those electrons once they pass in, 903 00:47:50,160 --> 00:47:53,080 Speaker 1: but it does change the overall electric charge of the 904 00:47:53,080 --> 00:47:55,560 Speaker 1: black hole, and you can measure that the same way 905 00:47:55,600 --> 00:47:58,160 Speaker 1: you can measure a black hole's mass increasing. You can 906 00:47:58,200 --> 00:48:01,880 Speaker 1: measure it's charge increasing or decreasing as you add charge 907 00:48:01,920 --> 00:48:05,840 Speaker 1: to it, because charge is conserved in our universe. But 908 00:48:05,920 --> 00:48:07,799 Speaker 1: how do you measure the charge of a black hole 909 00:48:08,000 --> 00:48:10,160 Speaker 1: if no information can come out? You can measure the 910 00:48:10,239 --> 00:48:12,160 Speaker 1: charge of a black hole the same way you measure 911 00:48:12,160 --> 00:48:15,480 Speaker 1: its mass, right, you measure the field it creates. Black 912 00:48:15,480 --> 00:48:19,320 Speaker 1: Holes can make gravitational fields that go past their event horizon, 913 00:48:19,600 --> 00:48:21,640 Speaker 1: and in the same way they can make electric fields 914 00:48:21,640 --> 00:48:24,719 Speaker 1: that go past their event horizon. You don't need information 915 00:48:24,760 --> 00:48:27,400 Speaker 1: to come out of the black hole in order for 916 00:48:27,640 --> 00:48:30,839 Speaker 1: that electric field to exist outside the black hole. Now, 917 00:48:30,880 --> 00:48:34,120 Speaker 1: I guess the question is that Mattes was thinking about. 918 00:48:34,160 --> 00:48:36,759 Speaker 1: It was that, you know, dark matter doesn't feel the 919 00:48:36,800 --> 00:48:39,480 Speaker 1: electromagnetic force. That's one of the things we know about it. 920 00:48:39,520 --> 00:48:41,839 Speaker 1: That's why it's invisible. You can't see it. So if 921 00:48:41,840 --> 00:48:44,440 Speaker 1: you made a black hole out of dark matter, does 922 00:48:44,480 --> 00:48:48,920 Speaker 1: that mean that the black hole wouldn't feel the electromagnetic force. Yeah, 923 00:48:49,000 --> 00:48:51,600 Speaker 1: that's true. If a black hole is made out of 924 00:48:51,680 --> 00:48:54,040 Speaker 1: dark matter, then it has no charge, and then it 925 00:48:54,040 --> 00:48:58,120 Speaker 1: wouldn't feel electromagnetism. An electron flew by a dark matter 926 00:48:58,200 --> 00:49:01,120 Speaker 1: black hole, it wouldn't feel any force, just the same 927 00:49:01,160 --> 00:49:04,040 Speaker 1: way it doesn't feel any force from any other neutral object. Well, 928 00:49:04,120 --> 00:49:06,160 Speaker 1: we will feel the force of gravity, it just wouldn't 929 00:49:06,160 --> 00:49:08,960 Speaker 1: feel the electromagnetic force. Right, Yes, it wouldn't feel any 930 00:49:08,960 --> 00:49:11,920 Speaker 1: electromagnetic force. It would only feel the gravity, just the 931 00:49:11,960 --> 00:49:14,800 Speaker 1: same way when it flies by any other neutral object. 932 00:49:15,000 --> 00:49:18,480 Speaker 1: It doesn't feel an electromagnetic force from it, only its gravity, 933 00:49:18,480 --> 00:49:20,759 Speaker 1: all right, So then I guess Matteos was thinking. If 934 00:49:20,800 --> 00:49:23,520 Speaker 1: that's true, then could we tell whether a black hole 935 00:49:24,239 --> 00:49:27,240 Speaker 1: is made out of dark matter or not by measuring 936 00:49:27,239 --> 00:49:28,960 Speaker 1: its charge? Like, if you see a black hole, you 937 00:49:29,000 --> 00:49:31,480 Speaker 1: measure its charge, you see that it's zero charge, or 938 00:49:31,560 --> 00:49:35,400 Speaker 1: that electrons are not affected by are not attracted or 939 00:49:35,440 --> 00:49:38,160 Speaker 1: repelled by this black hole. Would that be evidence that 940 00:49:38,239 --> 00:49:40,319 Speaker 1: this black hole is made out of dark match? Yeah, 941 00:49:40,400 --> 00:49:43,240 Speaker 1: And the last wrinkle there is to think about normal 942 00:49:43,360 --> 00:49:46,560 Speaker 1: matter black holes. Would they also have zero electric charge, 943 00:49:46,560 --> 00:49:49,200 Speaker 1: in which case you couldn't distinguish them from dark matter 944 00:49:49,239 --> 00:49:52,319 Speaker 1: black holes, or do they typically have some amount of 945 00:49:52,400 --> 00:49:57,280 Speaker 1: residual charge, in which case an exactly zero charge black 946 00:49:57,320 --> 00:49:59,840 Speaker 1: hole would be weird and would be a nice signal 947 00:50:00,000 --> 00:50:02,360 Speaker 1: of a dark matter black hole. So that's sort of 948 00:50:02,360 --> 00:50:04,239 Speaker 1: the last part of the question is how likely is 949 00:50:04,320 --> 00:50:06,720 Speaker 1: it for a normal matter black hole to have zero 950 00:50:06,760 --> 00:50:09,360 Speaker 1: electric charge? I see, So if a normal black hole 951 00:50:09,960 --> 00:50:13,239 Speaker 1: somehow in its formation aid more electrons than to say, 952 00:50:13,360 --> 00:50:17,520 Speaker 1: protons or positrons, then it would have an overall negative charge, 953 00:50:17,800 --> 00:50:21,359 Speaker 1: or if it ate didn't need enough electrons it would 954 00:50:21,400 --> 00:50:25,360 Speaker 1: have a positive charge. You're saying, maybe a zero charge 955 00:50:25,760 --> 00:50:27,600 Speaker 1: black hole wouldn't tell us that it's made out of 956 00:50:27,680 --> 00:50:30,799 Speaker 1: dark marror because it can also happen normally in a 957 00:50:30,840 --> 00:50:33,239 Speaker 1: black hole. It can't also happen normally, and it's a 958 00:50:33,239 --> 00:50:35,960 Speaker 1: bit of a probability thing. Black holes are just randomly 959 00:50:35,960 --> 00:50:39,880 Speaker 1: eating particles. What's the chances that it's exactly balanced that 960 00:50:39,960 --> 00:50:44,280 Speaker 1: it eats exactly as many positive particles as negative particles? 961 00:50:44,320 --> 00:50:47,320 Speaker 1: On one hand, is very unlikely to get exactly that balance. 962 00:50:47,400 --> 00:50:50,280 Speaker 1: On the other hand, is also the most likely outcome. 963 00:50:50,719 --> 00:50:52,840 Speaker 1: In the same way that like, if you flip a 964 00:50:52,880 --> 00:50:56,040 Speaker 1: coin a million times, what are the chances you're gonna 965 00:50:56,040 --> 00:51:00,480 Speaker 1: get exactly fifty percent heads and exactly fifty tails. Well, 966 00:51:00,520 --> 00:51:03,200 Speaker 1: it's unlikely to get exactly that number, it's also the 967 00:51:03,320 --> 00:51:06,759 Speaker 1: most likely outcome, right right. And also, I guess it 968 00:51:06,760 --> 00:51:08,879 Speaker 1: would be kind of hard to make a pure dark 969 00:51:08,880 --> 00:51:11,200 Speaker 1: matter black hole, right, Like, if you have a pure 970 00:51:11,280 --> 00:51:14,120 Speaker 1: dark matter black hole and one electron falls into it, 971 00:51:14,160 --> 00:51:16,080 Speaker 1: then suddenly it's got a charge. Yes, so that would 972 00:51:16,120 --> 00:51:19,040 Speaker 1: make this pretty challenging. But it is really interesting to 973 00:51:19,080 --> 00:51:22,800 Speaker 1: think about what is the charge distribution of black holes 974 00:51:22,800 --> 00:51:25,279 Speaker 1: out there in the universe. Are they all basically zero 975 00:51:25,400 --> 00:51:28,560 Speaker 1: or very close to zero? What is the overall charge 976 00:51:28,560 --> 00:51:30,879 Speaker 1: of these things? We have a whole episode planned about 977 00:51:30,920 --> 00:51:34,400 Speaker 1: the charge of the entire universe and the galaxy. But briefly, 978 00:51:34,520 --> 00:51:36,880 Speaker 1: most of the stuff that's out there is close to 979 00:51:37,120 --> 00:51:41,000 Speaker 1: neutral because the electromagnetic force is so strong that anything 980 00:51:41,040 --> 00:51:44,680 Speaker 1: that isn't neutralized, the force basically cancels it out. It 981 00:51:44,680 --> 00:51:47,799 Speaker 1: will like suck electrons off of something to balance it out. 982 00:51:48,200 --> 00:51:51,400 Speaker 1: Mostly like the Sun, for example, actually has a slight 983 00:51:51,560 --> 00:51:55,960 Speaker 1: charge because it's solar wind, has electrons and protons, but 984 00:51:56,000 --> 00:51:58,279 Speaker 1: it's easier for the electrons to escape the Sun than 985 00:51:58,360 --> 00:52:01,279 Speaker 1: protons because they have a lower mass. So the Sun 986 00:52:01,320 --> 00:52:03,920 Speaker 1: gives off more electrons and protons, so it has a 987 00:52:04,040 --> 00:52:09,120 Speaker 1: very slight positive charge. Interesting, I do agree the Sun 988 00:52:09,239 --> 00:52:11,720 Speaker 1: is a very positive influence on my life at least 989 00:52:12,640 --> 00:52:14,799 Speaker 1: for sure. I mean, it's not free of charge, but 990 00:52:15,000 --> 00:52:17,280 Speaker 1: I do have to wear some blood. So the answer 991 00:52:17,280 --> 00:52:18,960 Speaker 1: to this question, it's a really clever way to think 992 00:52:18,960 --> 00:52:21,400 Speaker 1: about what might be inside a black hole, but I 993 00:52:21,400 --> 00:52:24,799 Speaker 1: think be very challenging to prove that a black hole 994 00:52:24,880 --> 00:52:28,560 Speaker 1: is a dark matter, because it's possible to get zero 995 00:52:28,640 --> 00:52:31,920 Speaker 1: overall charge even without dark matter. Right. And also, I 996 00:52:32,000 --> 00:52:34,720 Speaker 1: guess it maybe points to this idea that black holes 997 00:52:34,760 --> 00:52:37,279 Speaker 1: are black holes, right, Like, even if it's dark matter 998 00:52:37,360 --> 00:52:40,680 Speaker 1: that falls into it, dark matter eventually just gets transformed 999 00:52:40,680 --> 00:52:44,000 Speaker 1: into pure energy. Right, So, like a black hole really 1000 00:52:44,120 --> 00:52:47,160 Speaker 1: kind of grinds everything up and maybe makes it impossible 1001 00:52:47,200 --> 00:52:49,040 Speaker 1: to tell if what you put in was dark matter 1002 00:52:49,160 --> 00:52:51,480 Speaker 1: or not. Yeah, we don't know the quantum states of 1003 00:52:51,520 --> 00:52:53,480 Speaker 1: the things inside the black hole. It's one of the 1004 00:52:53,520 --> 00:52:56,879 Speaker 1: deepest questions in modern physics, like what is the form 1005 00:52:56,920 --> 00:52:59,239 Speaker 1: of matter inside there? We don't know the answer because 1006 00:52:59,239 --> 00:53:01,640 Speaker 1: we don't have a theory of quantum gravity. We don't 1007 00:53:01,680 --> 00:53:05,360 Speaker 1: understand how gravity works for individual particles. So once the 1008 00:53:05,440 --> 00:53:07,439 Speaker 1: dark matter is inside the black hole, it's not really 1009 00:53:07,520 --> 00:53:10,680 Speaker 1: dark matter anymore. It's something weird and new that we 1010 00:53:10,760 --> 00:53:14,520 Speaker 1: don't understand. Interesting. All right, Well, thank you mass for 1011 00:53:14,560 --> 00:53:19,120 Speaker 1: that question. These were all pretty good questions, not really light. 1012 00:53:19,520 --> 00:53:23,640 Speaker 1: They're pretty heavy and content. Last one is super extra heavy. 1013 00:53:24,960 --> 00:53:27,440 Speaker 1: So for those of you on an intellectual diet, sorry 1014 00:53:27,440 --> 00:53:30,000 Speaker 1: for the heavy meal. Hopefully we had expanded your brain 1015 00:53:30,480 --> 00:53:33,879 Speaker 1: your waistline. But thank you for emitting these questions. These 1016 00:53:33,920 --> 00:53:36,960 Speaker 1: particles of curiosity that we love to absorb and to 1017 00:53:37,080 --> 00:53:39,440 Speaker 1: shoot back at you. Yeah, we hope we shed some 1018 00:53:39,520 --> 00:53:42,560 Speaker 1: light on these topics and then you come back for more. 1019 00:53:42,960 --> 00:53:53,560 Speaker 1: Thanks for joining us, see you next time. Thanks for listening, 1020 00:53:53,560 --> 00:53:56,279 Speaker 1: and remember that Daniel and Jorge explained the universe is 1021 00:53:56,320 --> 00:53:59,839 Speaker 1: a production of I heart Radio. For more podcast from 1022 00:53:59,840 --> 00:54:03,600 Speaker 1: my heart Radio, visit the i heart Radio app, Apple Podcasts, 1023 00:54:03,719 --> 00:54:11,800 Speaker 1: or wherever you listen to your favorite shows. H