1 00:00:08,440 --> 00:00:10,480 Speaker 1: Hey, Daniel, I have a question. You have to be 2 00:00:10,520 --> 00:00:13,080 Speaker 1: really good at math to be a physicist? Well, you know, 3 00:00:13,160 --> 00:00:15,440 Speaker 1: it depends a bit on what whether you want to 4 00:00:15,480 --> 00:00:18,920 Speaker 1: be a good physicist or a bad physicist. Actually, I 5 00:00:18,960 --> 00:00:21,639 Speaker 1: think that the most evil physicists are probably the ones 6 00:00:21,680 --> 00:00:23,759 Speaker 1: that are best at math. Do you say that because 7 00:00:23,760 --> 00:00:25,560 Speaker 1: you're not good at math? I say that because I'm 8 00:00:25,600 --> 00:00:28,600 Speaker 1: not an evil physicist. That's what all evil physicists say. 9 00:00:31,200 --> 00:00:33,559 Speaker 1: That's my answer to that question. But to answer your 10 00:00:33,560 --> 00:00:35,960 Speaker 1: other question, I think it depends a little bit on 11 00:00:36,159 --> 00:00:38,640 Speaker 1: the kind of math you have to do. What do 12 00:00:38,640 --> 00:00:41,440 Speaker 1: you mean, like complex or simple? Well, you know, for example, 13 00:00:41,720 --> 00:00:45,600 Speaker 1: I have no trouble doing calculations and boosts and rotations 14 00:00:45,600 --> 00:00:48,760 Speaker 1: and special relativity, but I mess up time zones at 15 00:00:48,800 --> 00:00:51,760 Speaker 1: least once a week. Yeah, those time zones can be 16 00:00:51,880 --> 00:00:55,520 Speaker 1: super complicated. You have to like add numbers and subtract numbers. 17 00:00:55,560 --> 00:00:58,840 Speaker 1: That's crazy. Sometimes you have to subtract different numbers based 18 00:00:58,840 --> 00:01:02,080 Speaker 1: on where you live and where I live. It's crazy, man. Yeah, 19 00:01:02,200 --> 00:01:04,920 Speaker 1: I know. There's there's like twenty four times. That's a 20 00:01:04,920 --> 00:01:07,720 Speaker 1: lot for one simple brain to handle. Too much for me. 21 00:01:08,000 --> 00:01:10,720 Speaker 1: Does not compute po A. We're late for our recording. 22 00:01:26,120 --> 00:01:28,240 Speaker 1: Hi am or handmte cartoonist and the co author of 23 00:01:28,280 --> 00:01:31,520 Speaker 1: Frequently Asked Questions about the Universe. Hi. I'm Daniel. I'm 24 00:01:31,560 --> 00:01:34,440 Speaker 1: a particle physicist and a professor at u C Irvine. 25 00:01:34,680 --> 00:01:37,120 Speaker 1: And the thing that's preventing me from having a far 26 00:01:37,280 --> 00:01:41,760 Speaker 1: flung evil empire is the time zones. Oh man, you're 27 00:01:41,800 --> 00:01:44,760 Speaker 1: like lex Luthor with a special weakness. Like, all we 28 00:01:44,800 --> 00:01:47,680 Speaker 1: have to do is what schedule and meeting with you, 29 00:01:47,760 --> 00:01:49,800 Speaker 1: and you'll be defeating exactly. I'll show up at the 30 00:01:49,840 --> 00:01:52,440 Speaker 1: wrong time and get frustrated and my plans would just 31 00:01:52,440 --> 00:01:54,800 Speaker 1: fall apart and SWAT team will be waiting for you 32 00:01:54,840 --> 00:01:57,960 Speaker 1: to arrestue. But you know, it's more complicated than you 33 00:01:58,000 --> 00:02:00,440 Speaker 1: make it sound, because it's not just that they're twenty 34 00:02:00,440 --> 00:02:03,560 Speaker 1: four time zones around the globe and that my team 35 00:02:03,680 --> 00:02:06,400 Speaker 1: is actually spread out over several of them. But the 36 00:02:06,400 --> 00:02:09,440 Speaker 1: time zones shift independently. There's two weeks of the year 37 00:02:09,560 --> 00:02:12,280 Speaker 1: when Europe doesn't have daylight Saving Time and we do, 38 00:02:12,480 --> 00:02:14,440 Speaker 1: and then there's some states in the US that do 39 00:02:14,560 --> 00:02:16,679 Speaker 1: and don't. It's a nightmare. Well, they have this new 40 00:02:16,680 --> 00:02:19,359 Speaker 1: thing called computers, Daniel, that will do all of these 41 00:02:19,400 --> 00:02:22,120 Speaker 1: calculations for you. I don't know if you've are up 42 00:02:22,120 --> 00:02:24,360 Speaker 1: on this technology, but all you have to do is 43 00:02:24,520 --> 00:02:27,120 Speaker 1: some type in your local times on the computer and 44 00:02:27,240 --> 00:02:29,320 Speaker 1: will tell you what time it is in other parts 45 00:02:29,320 --> 00:02:31,240 Speaker 1: of the planet. That's a good idea. We should use 46 00:02:31,280 --> 00:02:33,960 Speaker 1: computers to help with physics. I don't think anybody ever 47 00:02:34,040 --> 00:02:35,960 Speaker 1: thought of that before. I'm gonna get right on that. 48 00:02:36,080 --> 00:02:39,200 Speaker 1: You don't even need a I or anything. You just 49 00:02:39,280 --> 00:02:41,799 Speaker 1: need I. But anyways, welcome to our podcast, Daniel and 50 00:02:41,880 --> 00:02:44,840 Speaker 1: Jorge Explain the Universe, a production of I Heart Radio 51 00:02:44,960 --> 00:02:48,359 Speaker 1: in which we tried to translate things much more complicated 52 00:02:48,400 --> 00:02:51,560 Speaker 1: than the local time in Geneva. We want to understand 53 00:02:51,639 --> 00:02:55,440 Speaker 1: the very nature of the universe itself. If you dig 54 00:02:55,560 --> 00:02:58,800 Speaker 1: down into the firmament of human knowledge, can we penetrate 55 00:02:58,960 --> 00:03:03,519 Speaker 1: even below that, understand the actual bedrock foundation of the universe. 56 00:03:03,680 --> 00:03:06,560 Speaker 1: Can we take it all apart and understand the very 57 00:03:06,560 --> 00:03:11,240 Speaker 1: basic pieces of reality and translate those into our minds 58 00:03:11,280 --> 00:03:14,160 Speaker 1: so we can play with them, contemplate them, and understand 59 00:03:14,200 --> 00:03:17,280 Speaker 1: why the universe is the way that it is not 60 00:03:17,639 --> 00:03:20,320 Speaker 1: some other way. We ask all those big and hard 61 00:03:20,360 --> 00:03:23,120 Speaker 1: and difficult questions on the podcast, and sometimes we even 62 00:03:23,160 --> 00:03:26,239 Speaker 1: answer a few of them. Yeah, because life seems pretty normal, 63 00:03:26,320 --> 00:03:28,960 Speaker 1: pretty sensical on an everyday basis. But as you drill 64 00:03:29,080 --> 00:03:31,119 Speaker 1: down into the universe, and you already look out into 65 00:03:31,160 --> 00:03:34,320 Speaker 1: the cosmos, things get a little bit complicated. Even time 66 00:03:34,320 --> 00:03:37,920 Speaker 1: itself is more complicated than most people think. It's relative, 67 00:03:38,000 --> 00:03:40,760 Speaker 1: and it's different depending on where you are in the universe, 68 00:03:40,800 --> 00:03:42,760 Speaker 1: not just here on Earth. And the way the universe 69 00:03:42,800 --> 00:03:45,600 Speaker 1: works at the smallest skills and in the vicinity of 70 00:03:45,600 --> 00:03:48,200 Speaker 1: black holes is very different from the way the universe 71 00:03:48,320 --> 00:03:51,440 Speaker 1: seems to work in our normal, everyday lives. So we're 72 00:03:51,480 --> 00:03:56,360 Speaker 1: forced to try to translate this unknown, unfamiliar universe into 73 00:03:56,520 --> 00:03:58,880 Speaker 1: rules that we do find familiar, and along the way, 74 00:03:58,920 --> 00:04:01,840 Speaker 1: we use mathematics as a bridge to guide us into 75 00:04:01,880 --> 00:04:04,600 Speaker 1: the depths of the unknown truth. Because the way we 76 00:04:04,680 --> 00:04:08,400 Speaker 1: familiarize ourselves with the universe is by asking questions, wondering 77 00:04:08,440 --> 00:04:10,640 Speaker 1: how it all works, how can it all make sense? 78 00:04:10,640 --> 00:04:12,200 Speaker 1: And what kind of math do I need to know 79 00:04:12,520 --> 00:04:15,320 Speaker 1: to predict what's going to happen? And we ask questions 80 00:04:15,360 --> 00:04:17,880 Speaker 1: about the universe because we are curious people, and we 81 00:04:17,920 --> 00:04:21,080 Speaker 1: know that you ask questions about the universe because you 82 00:04:21,160 --> 00:04:23,719 Speaker 1: are all curious people, and we want to encourage that. 83 00:04:23,760 --> 00:04:26,360 Speaker 1: We love to hear your questions. We want you not 84 00:04:26,440 --> 00:04:28,640 Speaker 1: just to listen to us blah blah blah about the 85 00:04:28,680 --> 00:04:31,240 Speaker 1: nature of the universe, but to ask your own questions 86 00:04:31,240 --> 00:04:33,400 Speaker 1: to make sure the ideas we are talking about are 87 00:04:33,400 --> 00:04:36,440 Speaker 1: really clicking together in your mind, that you can do 88 00:04:36,520 --> 00:04:38,640 Speaker 1: more than just listen along and not but that you 89 00:04:38,680 --> 00:04:41,960 Speaker 1: can take these ideas and apply them to new situations. 90 00:04:42,040 --> 00:04:44,039 Speaker 1: And if that doesn't quite work, we want you to 91 00:04:44,040 --> 00:04:46,880 Speaker 1: reach out and send us an email to Questions at 92 00:04:46,960 --> 00:04:49,720 Speaker 1: Daniel and Jorge dot com so we can help straighten 93 00:04:49,720 --> 00:04:52,200 Speaker 1: it out for you. Yeah, because everybody has questions, and 94 00:04:52,240 --> 00:04:54,520 Speaker 1: sometimes the questions you might have about the universe are 95 00:04:54,560 --> 00:04:57,880 Speaker 1: the same questions that leading edge physicists have about what's 96 00:04:57,880 --> 00:05:00,400 Speaker 1: going on that's right, Like what time is it right 97 00:05:00,440 --> 00:05:03,520 Speaker 1: now in Geneva? Yeah, I guess technically you're a leading 98 00:05:03,560 --> 00:05:05,279 Speaker 1: edge physicist and you don't know what time it is. 99 00:05:05,360 --> 00:05:08,440 Speaker 1: So it's cutting edge research to look at your watch, Daniel. 100 00:05:08,480 --> 00:05:10,840 Speaker 1: It's the very forefront of human knowledge. Like am I 101 00:05:11,000 --> 00:05:12,799 Speaker 1: the only one here because I'm late for this meeting? 102 00:05:12,839 --> 00:05:14,919 Speaker 1: Or am I early for this meeting? Or is this 103 00:05:15,000 --> 00:05:17,120 Speaker 1: even the right month? For this meeting. Well, maybe you 104 00:05:17,120 --> 00:05:20,760 Speaker 1: should upgrade from using you know, sand clocks or sun 105 00:05:20,800 --> 00:05:24,080 Speaker 1: dials to know what time it is. I know you'd 106 00:05:24,080 --> 00:05:26,800 Speaker 1: like to be like O. G physicists, but you know 107 00:05:26,920 --> 00:05:29,640 Speaker 1: that those computers nowadays are pretty good. Yeah, they are 108 00:05:29,720 --> 00:05:31,479 Speaker 1: pretty good. But I think I need even more basic 109 00:05:31,480 --> 00:05:33,440 Speaker 1: health than that. I've shown them for flights at the 110 00:05:33,480 --> 00:05:36,160 Speaker 1: wrong day, I've shown for flights at the wrong airport. 111 00:05:36,560 --> 00:05:39,280 Speaker 1: I've landed the wrong airport. You know, sometimes I think 112 00:05:39,320 --> 00:05:41,120 Speaker 1: there's even a limit to what computers can do to 113 00:05:41,160 --> 00:05:43,360 Speaker 1: help somebody. And then you say I'm the one that's 114 00:05:43,400 --> 00:05:46,400 Speaker 1: always late. It sounds like you know, the one with 115 00:05:46,839 --> 00:05:49,280 Speaker 1: bigger problem here. Well, I'm just glad you're here at 116 00:05:49,320 --> 00:05:51,480 Speaker 1: the right time, at the same time as me. It's 117 00:05:51,480 --> 00:05:54,240 Speaker 1: one of the deepest questions in the universe, this Daniel 118 00:05:54,240 --> 00:05:56,600 Speaker 1: actually know what he's doing and where he's supposed to be. 119 00:05:56,760 --> 00:05:58,760 Speaker 1: We do get questions from listeners, and we love to 120 00:05:58,800 --> 00:06:01,159 Speaker 1: answer them here on the podcast because we get some 121 00:06:01,200 --> 00:06:04,520 Speaker 1: pretty amazing questions. Our listeners are pretty awesome, pretty curious, 122 00:06:04,600 --> 00:06:07,360 Speaker 1: and also they sort of know their stuff right, they 123 00:06:07,440 --> 00:06:09,600 Speaker 1: really do. I got a lot of really sophisticated and 124 00:06:09,640 --> 00:06:12,480 Speaker 1: well thought out questions. So, if you're out there and 125 00:06:12,520 --> 00:06:14,880 Speaker 1: you've been listening to the podcast for several years and 126 00:06:15,279 --> 00:06:18,400 Speaker 1: you have burning questions about the universe, don't be shy. 127 00:06:18,560 --> 00:06:20,840 Speaker 1: Please write to us. We really do want to hear 128 00:06:20,839 --> 00:06:23,040 Speaker 1: from you, and you really will hear back from us 129 00:06:23,120 --> 00:06:25,800 Speaker 1: right to questions at Daniel and Jorge dot com. So 130 00:06:25,880 --> 00:06:28,440 Speaker 1: today we have three awesome questions from listeners and they 131 00:06:28,600 --> 00:06:32,520 Speaker 1: range from how do you see photons? What color photons are? 132 00:06:32,680 --> 00:06:36,880 Speaker 1: And also what are the ingredients for life or the 133 00:06:37,000 --> 00:06:39,359 Speaker 1: not ingredients for not life? I guess it's kind of 134 00:06:39,360 --> 00:06:42,080 Speaker 1: a complex question. It's also involving baseball. So to the 135 00:06:42,120 --> 00:06:50,560 Speaker 1: on the podcast, we'll be tackling listener questions thirty one, 136 00:06:50,839 --> 00:06:55,080 Speaker 1: which somehow is coming after listener questions two. Who says 137 00:06:55,120 --> 00:06:57,760 Speaker 1: we have to do listener questions in order anyway? Man, 138 00:06:59,400 --> 00:07:01,720 Speaker 1: you say we try, we'll somehow back in time Daniel. Yeah, 139 00:07:01,760 --> 00:07:04,520 Speaker 1: that's a much simpler explanation than Daniel got confused and 140 00:07:04,560 --> 00:07:07,680 Speaker 1: scheduled these out of order. We've gone back in time 141 00:07:07,760 --> 00:07:11,080 Speaker 1: to answer ancient listener questions. Did you schedule in the 142 00:07:11,120 --> 00:07:14,120 Speaker 1: wrong time zone or something? Or are weally like thirty 143 00:07:14,120 --> 00:07:17,760 Speaker 1: two time zones back? Any number bigger than thirty is 144 00:07:17,800 --> 00:07:20,400 Speaker 1: basically infinity. You know, I like dealing with very small 145 00:07:20,440 --> 00:07:23,080 Speaker 1: things and very small numbers of things. There's a reason 146 00:07:23,080 --> 00:07:25,240 Speaker 1: we don't have thirty quarks in the standard model. You know, 147 00:07:25,240 --> 00:07:27,280 Speaker 1: we just lose track. Boy, we pay you to be 148 00:07:27,320 --> 00:07:30,960 Speaker 1: a physicist. I'm starting to think maybe we should see 149 00:07:30,960 --> 00:07:34,520 Speaker 1: some bona fides or have you do do a test 150 00:07:34,600 --> 00:07:36,560 Speaker 1: or something. Maybe because you did rely on the computer 151 00:07:36,640 --> 00:07:40,240 Speaker 1: to organize these podcasts, I thought you did. Don't you 152 00:07:40,240 --> 00:07:42,800 Speaker 1: have an Excel spreadsheet with the numbers and stuff. Are 153 00:07:42,800 --> 00:07:45,080 Speaker 1: you saying there's a user error here? It is possible 154 00:07:45,120 --> 00:07:47,440 Speaker 1: to make mistakes in Excel? That's true. But this is 155 00:07:47,480 --> 00:07:51,720 Speaker 1: the thirty guests technically thirty second time we answer listener questions, 156 00:07:51,760 --> 00:07:54,920 Speaker 1: even though this is the thirty first episode, right, this 157 00:07:55,000 --> 00:07:57,520 Speaker 1: is the second time we've said it's the thirty second time, 158 00:07:57,720 --> 00:08:01,120 Speaker 1: and we love answering listener questions. Let's jump right into it. 159 00:08:01,240 --> 00:08:03,880 Speaker 1: Today's first question comes from Sam, who is a question 160 00:08:03,920 --> 00:08:07,920 Speaker 1: about how we see photons. Hello Daniel and hard Day, 161 00:08:08,080 --> 00:08:11,320 Speaker 1: and thank you for your wonderful podcast and especially thank 162 00:08:11,360 --> 00:08:15,120 Speaker 1: you for being so accessible to answer listener questions. I 163 00:08:15,200 --> 00:08:18,400 Speaker 1: have a follow up question to a recent listeners question. 164 00:08:18,560 --> 00:08:21,400 Speaker 1: In that podcast, there was discussion about photons and their 165 00:08:21,440 --> 00:08:25,360 Speaker 1: speed around black holes. The discussion made references to things 166 00:08:25,400 --> 00:08:29,600 Speaker 1: like two observers of a photons movements and seeing photons 167 00:08:29,640 --> 00:08:34,040 Speaker 1: moving away from us. I understand that we infer the direction, velocity, 168 00:08:34,080 --> 00:08:37,959 Speaker 1: and composition of objects based on the information conveyed by 169 00:08:37,960 --> 00:08:41,360 Speaker 1: the stream of photons that I received, which I or 170 00:08:41,400 --> 00:08:44,880 Speaker 1: my instruments used to constructed details of that object. But 171 00:08:44,960 --> 00:08:47,360 Speaker 1: I was confused about the discussion an idea of two 172 00:08:47,400 --> 00:08:51,040 Speaker 1: observers seeing the same photon or seeing a photon moving away, 173 00:08:51,400 --> 00:08:53,960 Speaker 1: as I didn't know how that information could be sent 174 00:08:54,160 --> 00:08:57,200 Speaker 1: by a photon and to two observers at the same time. 175 00:08:57,640 --> 00:09:01,120 Speaker 1: Thanks again for helping me and others better understand this 176 00:09:01,280 --> 00:09:04,920 Speaker 1: weird universe. Alright, awesome question, Thank you, Sam. And it's 177 00:09:05,200 --> 00:09:07,840 Speaker 1: I guess it's a follow up question to a question 178 00:09:07,880 --> 00:09:10,680 Speaker 1: we had in a in another episode. But is it 179 00:09:10,800 --> 00:09:12,720 Speaker 1: from an episode we did in the future or in 180 00:09:12,720 --> 00:09:15,480 Speaker 1: the past. It's an episode we haven't yet done in 181 00:09:15,520 --> 00:09:20,280 Speaker 1: the past, and so Sam is psychic. Maybe Sam is 182 00:09:20,360 --> 00:09:23,480 Speaker 1: just many times zones ahead of us somehow in Geneva 183 00:09:24,120 --> 00:09:26,840 Speaker 1: is seeing Denmark or something They're pretty smart. In Denmark, 184 00:09:26,920 --> 00:09:28,800 Speaker 1: they are pretty smart. You can see the future. But 185 00:09:28,880 --> 00:09:31,160 Speaker 1: I guess this question is has to do with this 186 00:09:31,240 --> 00:09:34,760 Speaker 1: thought experiment we talked about in an episode before about 187 00:09:34,920 --> 00:09:37,240 Speaker 1: how do you tell if if photons changed their path 188 00:09:37,320 --> 00:09:40,320 Speaker 1: around a black hole? Yeah, we were talking about photons 189 00:09:40,360 --> 00:09:43,680 Speaker 1: having different speeds than just the speed of light, and 190 00:09:43,720 --> 00:09:45,720 Speaker 1: if you were far away from a black hole, for example, 191 00:09:45,800 --> 00:09:48,280 Speaker 1: you could see photons get bent around a black hole. 192 00:09:48,440 --> 00:09:50,959 Speaker 1: You could see them crawl out of the gravitational well, 193 00:09:51,160 --> 00:09:53,720 Speaker 1: very very slowly. And we had a whole conversation about 194 00:09:53,720 --> 00:09:56,400 Speaker 1: how the speed of light for photons is really just 195 00:09:56,440 --> 00:09:59,400 Speaker 1: the speed of light locally, and that far away photons 196 00:09:59,640 --> 00:10:02,040 Speaker 1: might have all sorts of weird different speeds. It's a 197 00:10:02,080 --> 00:10:04,920 Speaker 1: really complicated topic in general relativity, right. I think the 198 00:10:04,920 --> 00:10:06,640 Speaker 1: experiment was that you know, if you have you have 199 00:10:06,679 --> 00:10:08,800 Speaker 1: a black hole out there in space, and there are 200 00:10:08,800 --> 00:10:12,760 Speaker 1: two photons kind of flying near it, you know, one 201 00:10:12,840 --> 00:10:14,719 Speaker 1: near it or one less near it, they're going to 202 00:10:14,800 --> 00:10:17,320 Speaker 1: do different things. And I think Sam's question is, like, 203 00:10:17,400 --> 00:10:19,960 Speaker 1: how do we know what those photons are doing if 204 00:10:20,000 --> 00:10:23,200 Speaker 1: they're moving away from us or they're moving perpendicular to us, Like, 205 00:10:23,240 --> 00:10:25,319 Speaker 1: how do you see a photon moving if it's not 206 00:10:25,679 --> 00:10:27,720 Speaker 1: you know, hitting your eyeball. Yeah. So it's a really 207 00:10:27,720 --> 00:10:29,880 Speaker 1: great question because Sam is thinking, like, how do you 208 00:10:29,920 --> 00:10:33,040 Speaker 1: actually do this experiment? Is this something physicists or just 209 00:10:33,160 --> 00:10:35,840 Speaker 1: thinking about, or is this something you could actually measure 210 00:10:35,840 --> 00:10:37,839 Speaker 1: in the universe, which is a really important thing to do, 211 00:10:37,880 --> 00:10:40,800 Speaker 1: because physics is more than just like thinking about things. 212 00:10:41,000 --> 00:10:43,080 Speaker 1: It's also about going out there in the universe and 213 00:10:43,160 --> 00:10:46,360 Speaker 1: making measurements. Many times we thought the universe worked one 214 00:10:46,400 --> 00:10:48,480 Speaker 1: way and then went out there to confirm it and 215 00:10:48,480 --> 00:10:51,679 Speaker 1: discovered oops, nope, the universe works a different way. So 216 00:10:51,800 --> 00:10:55,320 Speaker 1: definitely doing experiments and making measurements a vital part of 217 00:10:55,480 --> 00:10:58,320 Speaker 1: learning about the universe. Yeah, so I guess maybe let's 218 00:10:58,320 --> 00:11:01,040 Speaker 1: break it down Daniel, Like, you have a photon out 219 00:11:01,040 --> 00:11:03,160 Speaker 1: there flying through space, how do you actually see it. 220 00:11:03,320 --> 00:11:05,040 Speaker 1: If you can't see it, your mental picture of a 221 00:11:05,040 --> 00:11:08,840 Speaker 1: photon is probably misleading. You're imagining like some pulse of 222 00:11:08,920 --> 00:11:11,920 Speaker 1: light that flows through the universe. Maybe it flies past you, 223 00:11:12,320 --> 00:11:15,240 Speaker 1: and you might even be thinking about it, like glowing 224 00:11:15,760 --> 00:11:18,560 Speaker 1: that you could see a photon fly by you, because 225 00:11:18,640 --> 00:11:20,840 Speaker 1: in the end, it's light, right, you can see light. 226 00:11:21,080 --> 00:11:23,800 Speaker 1: The truth is that you can only see photons that 227 00:11:23,880 --> 00:11:27,120 Speaker 1: actually hit your eyeballs. Like if you're in a dark 228 00:11:27,200 --> 00:11:29,480 Speaker 1: room and a photon flies right in front of your 229 00:11:29,480 --> 00:11:32,560 Speaker 1: nose but doesn't hit your eyeball, you can't see it. 230 00:11:32,559 --> 00:11:35,720 Speaker 1: It's invisible to you. You would never know that it's there. 231 00:11:35,880 --> 00:11:37,920 Speaker 1: I mean, it's not like a laser beam in a 232 00:11:38,000 --> 00:11:41,760 Speaker 1: Star Wars movie, right, like a laser gun shot, right, 233 00:11:41,840 --> 00:11:43,920 Speaker 1: you won't see a stream of light flying pass here, 234 00:11:43,960 --> 00:11:46,200 Speaker 1: exactly like in those spy movies when they have to 235 00:11:46,240 --> 00:11:48,600 Speaker 1: do it dance through a room full of laser beams 236 00:11:48,600 --> 00:11:50,760 Speaker 1: and not interrupt any of them. The reason you see 237 00:11:50,800 --> 00:11:53,840 Speaker 1: those laser beams is because they're reflecting off dust in 238 00:11:53,880 --> 00:11:56,360 Speaker 1: the air, or if they're really intense, maybe they're even 239 00:11:56,400 --> 00:12:00,360 Speaker 1: ionizing the air so the air glows. But in a vacuum, 240 00:12:00,360 --> 00:12:03,400 Speaker 1: if the photon is moving unobstructed in front of you, 241 00:12:03,400 --> 00:12:05,480 Speaker 1: you wouldn't see it would just pass right in front 242 00:12:05,520 --> 00:12:08,120 Speaker 1: of you and be totally invisible. Right. And also in 243 00:12:08,160 --> 00:12:10,120 Speaker 1: the case of the laser that you can see, it's 244 00:12:10,160 --> 00:12:12,480 Speaker 1: like it's shooting a whole bunch of photons and some 245 00:12:12,559 --> 00:12:14,720 Speaker 1: of them are hitting the dust particles or the smoke 246 00:12:14,800 --> 00:12:17,760 Speaker 1: particles in the air and then bouncing into your eyeballs, 247 00:12:17,800 --> 00:12:20,320 Speaker 1: but the other ones are just going right through right exactly. 248 00:12:20,320 --> 00:12:23,480 Speaker 1: And in the more realistic spy movies, the lasers are 249 00:12:23,520 --> 00:12:25,960 Speaker 1: invisible and then throw a handful of sawdust into the 250 00:12:25,960 --> 00:12:28,760 Speaker 1: air to make the lasers visible again. So the point 251 00:12:28,840 --> 00:12:32,120 Speaker 1: is that you can't actually see photons unless they hit 252 00:12:32,200 --> 00:12:35,319 Speaker 1: your eyeball or some detector. So he's absolutely right that 253 00:12:35,360 --> 00:12:38,000 Speaker 1: a photon passing by a black hole and getting bent 254 00:12:38,040 --> 00:12:40,880 Speaker 1: and shot off in another direction, you couldn't literally see 255 00:12:40,920 --> 00:12:44,000 Speaker 1: that with your eyeballs right in a vacuum, although they don't. 256 00:12:44,040 --> 00:12:47,320 Speaker 1: We talk about once some special materials or some special 257 00:12:47,559 --> 00:12:50,280 Speaker 1: situations where like a photon makes like a wake or something. 258 00:12:50,440 --> 00:12:52,840 Speaker 1: We did talk about the really amazing experiments that show 259 00:12:52,960 --> 00:12:55,599 Speaker 1: that the human eyeball can see a single photon, and 260 00:12:55,640 --> 00:12:58,840 Speaker 1: they do this by splitting a photon in two. There 261 00:12:58,880 --> 00:13:01,160 Speaker 1: are special materials that will take a photon and like 262 00:13:01,240 --> 00:13:04,400 Speaker 1: split it into two of lower energy, and so then 263 00:13:04,440 --> 00:13:07,840 Speaker 1: you can see one while the other one is like undisturbed. 264 00:13:08,120 --> 00:13:10,720 Speaker 1: But that's not technically the same thing. So a single 265 00:13:10,760 --> 00:13:14,120 Speaker 1: photon traveling out there in the vacuum, you can't actually 266 00:13:14,120 --> 00:13:17,080 Speaker 1: see it go pass unless it hits your eyeball exactly, 267 00:13:17,160 --> 00:13:19,439 Speaker 1: or unless you have a friend whose eyeball it hits 268 00:13:19,480 --> 00:13:21,440 Speaker 1: and then they tell you about it. So then you 269 00:13:21,440 --> 00:13:24,920 Speaker 1: couldn't see a photon traveling away from you either, right, yeah, exactly. 270 00:13:24,960 --> 00:13:27,240 Speaker 1: You shoot a laser beam out into the universe, you're 271 00:13:27,280 --> 00:13:30,400 Speaker 1: not going to see that beam unless it hits something 272 00:13:30,440 --> 00:13:33,000 Speaker 1: and bounces back. Right. If it hits dust or smoke 273 00:13:33,080 --> 00:13:34,960 Speaker 1: in front of you, you'll see where it is. Like 274 00:13:35,080 --> 00:13:37,560 Speaker 1: at night, if you shine a flashlight up at the sky, 275 00:13:37,840 --> 00:13:39,720 Speaker 1: you can see the beam a little bit if it's 276 00:13:39,760 --> 00:13:43,079 Speaker 1: reflecting off of dust, but mostly it's invisible. The aliens 277 00:13:43,120 --> 00:13:45,800 Speaker 1: on Alpha centauri that receive your photons, they can see 278 00:13:45,840 --> 00:13:48,920 Speaker 1: it eventually, but you can't see the photons unless they've 279 00:13:48,960 --> 00:13:50,840 Speaker 1: hit something and come back to you. Right. So, then 280 00:13:50,840 --> 00:13:53,480 Speaker 1: in these thought experiments where you shoot in a photon 281 00:13:53,520 --> 00:13:56,880 Speaker 1: at a black hole, in theory, the photon will slow 282 00:13:57,000 --> 00:13:59,679 Speaker 1: down right as it approaches the black hole and move 283 00:14:00,080 --> 00:14:03,160 Speaker 1: lower than the speed of light to you, but you 284 00:14:03,200 --> 00:14:05,480 Speaker 1: won't actually be able to see it doing that. Right, So, 285 00:14:05,520 --> 00:14:07,680 Speaker 1: to be very precise and specific, if you're just a 286 00:14:07,760 --> 00:14:11,200 Speaker 1: single observer and you're shooting that photon towards black hole. 287 00:14:11,400 --> 00:14:13,840 Speaker 1: Then Sam is exactly right, you won't see it. But 288 00:14:13,880 --> 00:14:15,559 Speaker 1: this is a thought experiment, and we do this in 289 00:14:15,600 --> 00:14:17,480 Speaker 1: physics all the time. We try to imagine what might 290 00:14:17,520 --> 00:14:20,960 Speaker 1: happen in various scenarios. In those thought experiments were often 291 00:14:21,000 --> 00:14:23,480 Speaker 1: skipping an implied step. If we were to actually do 292 00:14:23,520 --> 00:14:25,920 Speaker 1: that experiment, it would look different. We would set up 293 00:14:25,960 --> 00:14:29,400 Speaker 1: detectors everywhere, or we would have huge teams of observers 294 00:14:29,440 --> 00:14:31,840 Speaker 1: in lots of different places so they could see stuff. 295 00:14:31,880 --> 00:14:33,400 Speaker 1: And that's kind of boring in a lot of work, 296 00:14:33,440 --> 00:14:35,040 Speaker 1: so we don't talk about that stuff when we set 297 00:14:35,120 --> 00:14:37,800 Speaker 1: up the thought experiment. But Sam's exactly right that in 298 00:14:37,880 --> 00:14:41,080 Speaker 1: order to actually detect those photons, to do that experiment, 299 00:14:41,400 --> 00:14:43,680 Speaker 1: you would have to have more than just the one observer. 300 00:14:43,800 --> 00:14:46,000 Speaker 1: You have to have whole teams of observers and careful 301 00:14:46,080 --> 00:14:49,280 Speaker 1: rules about how they synchronize and communicate that information. Yeah, 302 00:14:49,280 --> 00:14:51,000 Speaker 1: you have to figure out what time zones are in 303 00:14:51,240 --> 00:14:53,840 Speaker 1: I mean that would just be impossible for physicists. You 304 00:14:53,960 --> 00:14:56,520 Speaker 1: just sit there in the zoom waiting right all by 305 00:14:56,560 --> 00:14:59,240 Speaker 1: yourself for somebody to send you the details, and we're 306 00:14:59,240 --> 00:15:01,080 Speaker 1: never going to get this paper app right. I think 307 00:15:01,080 --> 00:15:02,840 Speaker 1: what you're saying is that in order to see what 308 00:15:02,840 --> 00:15:04,920 Speaker 1: happens to a photon that flies near a black hole, 309 00:15:05,040 --> 00:15:07,040 Speaker 1: you would have to maybe put a detector near the 310 00:15:07,040 --> 00:15:09,440 Speaker 1: black hole or something right, and measure how long it 311 00:15:09,440 --> 00:15:12,440 Speaker 1: takes for the photon to get to that detector. Yeah, exactly, 312 00:15:12,480 --> 00:15:14,240 Speaker 1: And this is true. And lots of thought experiments we 313 00:15:14,280 --> 00:15:17,200 Speaker 1: do about special relativity, lots of examples of people going 314 00:15:17,240 --> 00:15:19,160 Speaker 1: near the speed of light and measuring their time and 315 00:15:19,200 --> 00:15:21,560 Speaker 1: looking at each other's times. You often have to have 316 00:15:21,640 --> 00:15:25,360 Speaker 1: like whole teams of observers to actually conduct those experiments 317 00:15:25,400 --> 00:15:28,040 Speaker 1: in real life. So we've thought about how that might work, 318 00:15:28,080 --> 00:15:30,960 Speaker 1: and we've proven ourselves that technically it's possible to make 319 00:15:31,000 --> 00:15:33,320 Speaker 1: these observations if you have the right team. And we 320 00:15:33,360 --> 00:15:35,640 Speaker 1: don't usually talk about that part in the thought experiment 321 00:15:35,680 --> 00:15:37,920 Speaker 1: because it's like the boring details and you would actually 322 00:15:37,920 --> 00:15:41,080 Speaker 1: have to organize to make things work, right. I think 323 00:15:41,080 --> 00:15:42,960 Speaker 1: maybe what Sam is getting at is that in the 324 00:15:43,000 --> 00:15:45,640 Speaker 1: thought experiment, you talk about what happens to one photon 325 00:15:45,840 --> 00:15:48,080 Speaker 1: as it goes near a black hole, it would slow down, 326 00:15:48,520 --> 00:15:50,920 Speaker 1: But maybe in a real life experiment it wouldn't just 327 00:15:50,960 --> 00:15:53,520 Speaker 1: be one photon like you shoot, maybe two photons at 328 00:15:53,520 --> 00:15:55,320 Speaker 1: the same time, and one of them you would measure 329 00:15:55,480 --> 00:15:57,400 Speaker 1: halfway through and the other one you would measure in 330 00:15:57,400 --> 00:15:59,200 Speaker 1: another point. Do you know what I mean? Like you, 331 00:15:59,200 --> 00:16:01,240 Speaker 1: you would need more than one photon. You can't just 332 00:16:01,480 --> 00:16:03,760 Speaker 1: know what's going to happen or what is happening to 333 00:16:03,840 --> 00:16:06,520 Speaker 1: one photon. Yeah, sometimes you can measure what happens to 334 00:16:06,640 --> 00:16:09,360 Speaker 1: just one photon, although a lot of these experiments you 335 00:16:09,400 --> 00:16:11,600 Speaker 1: want to know what would happen in various circumstances. So 336 00:16:11,600 --> 00:16:14,800 Speaker 1: you're right, you would need multiple photons, and anyway you'd 337 00:16:14,840 --> 00:16:17,800 Speaker 1: want to replicate your experiments and make multiple measurements. So 338 00:16:17,880 --> 00:16:21,440 Speaker 1: practically speaking, that's exactly right. You'd want a stream of photons. 339 00:16:21,640 --> 00:16:23,560 Speaker 1: So sometimes you want to separate them so you know 340 00:16:23,680 --> 00:16:26,880 Speaker 1: which photon is which. Like an experiment where we're figuring 341 00:16:26,880 --> 00:16:29,160 Speaker 1: out if the human eye can see a single photon, 342 00:16:29,240 --> 00:16:32,600 Speaker 1: it's very important to know when one photon arrives at 343 00:16:32,600 --> 00:16:34,600 Speaker 1: the eye, so you can know if it arrived and 344 00:16:34,680 --> 00:16:37,080 Speaker 1: if the person saw a real photon were just made 345 00:16:37,080 --> 00:16:39,520 Speaker 1: of a flash. So sometimes you want them to be 346 00:16:39,600 --> 00:16:42,320 Speaker 1: well separated, right, So I guess that's the answer to 347 00:16:42,400 --> 00:16:44,920 Speaker 1: the question, then, is that you can't see a photon 348 00:16:44,960 --> 00:16:47,840 Speaker 1: moving away from you, but you could set up a 349 00:16:47,880 --> 00:16:50,480 Speaker 1: detector ahead of you to catch that photon right, and 350 00:16:50,480 --> 00:16:52,520 Speaker 1: then that way you would know what happened to that photon. 351 00:16:52,920 --> 00:16:55,680 Speaker 1: And you can imagine filling the universe with detectors or 352 00:16:55,720 --> 00:16:58,800 Speaker 1: with assistance, you know, to take note of things and 353 00:16:59,200 --> 00:17:02,560 Speaker 1: later seem chronize them against your clocks. And so if 354 00:17:02,600 --> 00:17:05,679 Speaker 1: you add that sort of implicitly to all the thought experiments, 355 00:17:05,800 --> 00:17:08,200 Speaker 1: you can think more concretely about how you would actually 356 00:17:08,240 --> 00:17:11,040 Speaker 1: do these things right. But unfortunately that's boring and a 357 00:17:11,040 --> 00:17:13,760 Speaker 1: lot of work, which apparently physicists are not willing to 358 00:17:13,800 --> 00:17:16,399 Speaker 1: do because then you have to get out of your couch. 359 00:17:16,480 --> 00:17:18,320 Speaker 1: I guess, well, you have to organize it, and everybody 360 00:17:18,320 --> 00:17:21,560 Speaker 1: shows up at the wrong time and so like yeah, 361 00:17:21,680 --> 00:17:26,720 Speaker 1: and then so it's practically impossible. At least one physicist answered, 362 00:17:27,920 --> 00:17:31,600 Speaker 1: you should try harder working on Do you see what 363 00:17:31,640 --> 00:17:35,680 Speaker 1: they say? Idea that means the work is on you, Sam. 364 00:17:35,720 --> 00:17:37,320 Speaker 1: All right, well, let's get to some of these other 365 00:17:37,400 --> 00:17:40,720 Speaker 1: questions about the ingredients of life and maybe other planets, 366 00:17:40,800 --> 00:17:45,240 Speaker 1: and also about the red shifting of photons. But first 367 00:17:45,320 --> 00:17:59,840 Speaker 1: let's take a quick break. All right, we are answering 368 00:18:00,000 --> 00:18:02,159 Speaker 1: there there no questions here today, and we have some 369 00:18:02,240 --> 00:18:05,760 Speaker 1: awesome questions here from people about the ingredients of life 370 00:18:05,800 --> 00:18:08,720 Speaker 1: and also the color of photons. Our next question is 371 00:18:08,800 --> 00:18:12,359 Speaker 1: from Christian. Hi, there, Daniel, and Jorge. I just wanted 372 00:18:12,400 --> 00:18:14,920 Speaker 1: to start off by saying, I love your podcast. I've 373 00:18:14,960 --> 00:18:18,040 Speaker 1: been watching baseball lately and that's inspired my question. So 374 00:18:18,080 --> 00:18:20,200 Speaker 1: in baseball, we see a lot of teams do what's 375 00:18:20,200 --> 00:18:23,119 Speaker 1: called recreation in the aggregate. So they maybe lose a 376 00:18:23,160 --> 00:18:26,800 Speaker 1: good player or a great player, and they try to 377 00:18:26,840 --> 00:18:30,320 Speaker 1: recreate that player's effect with multiple good players. So my 378 00:18:30,400 --> 00:18:33,639 Speaker 1: question is this, you're the GM of the universe. For 379 00:18:33,720 --> 00:18:38,920 Speaker 1: whatever reason, we lose the crucial elements of life, water, carbon, oxygen, etcetera. 380 00:18:39,040 --> 00:18:41,959 Speaker 1: Maybe they're traded to the Mets, whatever, How would you, 381 00:18:42,359 --> 00:18:46,199 Speaker 1: as GM of the universe, recreate these crucial elements in 382 00:18:46,240 --> 00:18:49,160 Speaker 1: the aggregate? Are these elements so unique that no other 383 00:18:49,200 --> 00:18:53,040 Speaker 1: elements or combination of elements could recreate their effect? What 384 00:18:53,240 --> 00:18:56,560 Speaker 1: qualities in particular make these elements so conducive to life 385 00:18:57,000 --> 00:18:59,520 Speaker 1: and why might they be unique? Thanks again for taking 386 00:18:59,520 --> 00:19:03,800 Speaker 1: the time to review my question and go twins. Awesome 387 00:19:03,920 --> 00:19:06,159 Speaker 1: question from Christian, Although he made a crucial mistake in 388 00:19:06,200 --> 00:19:10,000 Speaker 1: that question? What's that he assumed we followed sports. We 389 00:19:10,040 --> 00:19:12,359 Speaker 1: can't answer your question, Christian, because we have no idea 390 00:19:12,440 --> 00:19:16,040 Speaker 1: what you're talking about. Sorry, yeah, next question. No, I'm 391 00:19:16,040 --> 00:19:17,800 Speaker 1: just kidding a. Let's see the movie Moneyball, So I 392 00:19:17,800 --> 00:19:21,679 Speaker 1: think I'm sort of qualified answer this question. That's right, 393 00:19:21,960 --> 00:19:24,560 Speaker 1: Jorge did his homework, that's right. Yeah, and uh, in 394 00:19:24,560 --> 00:19:27,119 Speaker 1: this case, the GM is Brad Pitt? Right exactly? Is 395 00:19:27,160 --> 00:19:29,240 Speaker 1: Brad Pitt can also play you in the movie about 396 00:19:29,240 --> 00:19:33,600 Speaker 1: your life? Yeah? I should play Brad Pitt in his movie, right, 397 00:19:34,800 --> 00:19:37,400 Speaker 1: that's definitely happening. Yeah, So this is an interesting question. 398 00:19:37,440 --> 00:19:40,720 Speaker 1: It's almost like fantasy football mixed with physics. Or would 399 00:19:40,720 --> 00:19:44,280 Speaker 1: you say it's fantasy physics. It's more like fantasy chemistry. Yeah, 400 00:19:44,320 --> 00:19:47,840 Speaker 1: but it's really interesting question about like how life might 401 00:19:48,000 --> 00:19:51,560 Speaker 1: operate without the basic building blocks that we use. And 402 00:19:51,600 --> 00:19:54,400 Speaker 1: it's not just a fantasy, you know, biochemists have been 403 00:19:54,400 --> 00:19:56,639 Speaker 1: thinking about this for a while. Is the recipe of 404 00:19:56,720 --> 00:19:59,200 Speaker 1: life that we have here on Earth? The only possible 405 00:19:59,280 --> 00:20:02,400 Speaker 1: recipe are we being like narrow minded when we look 406 00:20:02,440 --> 00:20:05,479 Speaker 1: for biosignatures on other planets that are similar to the 407 00:20:05,480 --> 00:20:08,440 Speaker 1: ones on our planets. Shouldn't we be thinking about other 408 00:20:08,480 --> 00:20:11,480 Speaker 1: ways life might evolve so that we can anticipate it 409 00:20:11,480 --> 00:20:14,359 Speaker 1: and look for it more effectively in other places. I 410 00:20:14,400 --> 00:20:16,880 Speaker 1: think it's a really cool thing to think about. Yeah, 411 00:20:16,920 --> 00:20:19,000 Speaker 1: and so I guess specifically, his question is like, if 412 00:20:19,000 --> 00:20:22,600 Speaker 1: you're the general manager of the universe, I guess, or Earth, 413 00:20:22,720 --> 00:20:24,879 Speaker 1: and you're trying to make life, and you have these 414 00:20:25,000 --> 00:20:29,240 Speaker 1: ingredients water, carbon, and oxygen, but somebody took away one 415 00:20:29,240 --> 00:20:31,960 Speaker 1: of your ingredients or they got traded to I don't know, 416 00:20:32,200 --> 00:20:35,160 Speaker 1: another universe or another planet. Could you find a way 417 00:20:35,160 --> 00:20:37,960 Speaker 1: to replace these elements to still make life? Yeah, you know, 418 00:20:38,000 --> 00:20:41,160 Speaker 1: I know that baseball fanatics are pretty fanatic, but he's 419 00:20:41,160 --> 00:20:43,560 Speaker 1: basically putting the GM at the god level of the 420 00:20:43,640 --> 00:20:49,800 Speaker 1: universe here, Yeah, godly manager. I guess baseball is Christians religion. 421 00:20:49,880 --> 00:20:52,120 Speaker 1: But it's a really interesting question whether you could make 422 00:20:52,200 --> 00:20:56,760 Speaker 1: life with other fundamental bits of biochemistry. And Christians specifically 423 00:20:56,800 --> 00:21:01,040 Speaker 1: asked about carbon and water and oxygen, and he's right, 424 00:21:01,320 --> 00:21:04,720 Speaker 1: those are essential bits in our kind of life, and 425 00:21:04,760 --> 00:21:07,080 Speaker 1: so it's fun to think about whether you could build 426 00:21:07,119 --> 00:21:10,119 Speaker 1: life without them, right, And I guess specifically, like, you know, 427 00:21:10,160 --> 00:21:11,880 Speaker 1: we should go through each one like if you took 428 00:21:11,920 --> 00:21:15,000 Speaker 1: out carbon, could you still find something to replace it 429 00:21:15,440 --> 00:21:18,159 Speaker 1: or a set of other molecules or atoms to replace 430 00:21:18,200 --> 00:21:20,520 Speaker 1: it to make life? Yeah, And so to answer that, 431 00:21:20,560 --> 00:21:22,320 Speaker 1: you have to think about like, well, why do we 432 00:21:22,400 --> 00:21:25,320 Speaker 1: use carbon? Why is life carbon based? What is the 433 00:21:25,400 --> 00:21:28,000 Speaker 1: utility of carbon? If you're going to replace it, what 434 00:21:28,000 --> 00:21:29,639 Speaker 1: do you kind of thing you're gonna look for? And 435 00:21:29,680 --> 00:21:32,199 Speaker 1: carbon is pretty ubiquitous in life. I mean, what we 436 00:21:32,240 --> 00:21:36,000 Speaker 1: call organic molecules are the ones that have carbon in them, right, 437 00:21:36,080 --> 00:21:38,960 Speaker 1: And there's a reason for that because carbon is very flexible. 438 00:21:39,040 --> 00:21:41,399 Speaker 1: The way that it's electrons or organized means that it 439 00:21:41,440 --> 00:21:44,439 Speaker 1: can build all sorts of really interesting bonds. It's like 440 00:21:44,480 --> 00:21:47,520 Speaker 1: that really useful lego brick that you're can attach other 441 00:21:47,600 --> 00:21:50,240 Speaker 1: stuff too. And so you can make all sorts of 442 00:21:50,280 --> 00:21:53,800 Speaker 1: really interesting molecules and complicated molecules that can swap around 443 00:21:53,840 --> 00:21:55,680 Speaker 1: a lot. And so it allows for us to build 444 00:21:55,840 --> 00:21:59,480 Speaker 1: really complex things like DNA that can store a lot 445 00:21:59,520 --> 00:22:02,040 Speaker 1: of information asian, and it allows us to create really 446 00:22:02,040 --> 00:22:06,040 Speaker 1: complicated metabolisms right to move energy around and create the 447 00:22:06,080 --> 00:22:09,119 Speaker 1: processes that we need for life. So it's really at 448 00:22:09,160 --> 00:22:11,679 Speaker 1: the foundation of all the biochemistry of life, as we 449 00:22:11,720 --> 00:22:14,680 Speaker 1: know it interesting, right, Is it true that all life 450 00:22:14,680 --> 00:22:16,520 Speaker 1: as we know it uses carbon? Like, do we know 451 00:22:16,560 --> 00:22:18,879 Speaker 1: of any life that doesn't use carbon? We do not, 452 00:22:19,080 --> 00:22:22,280 Speaker 1: absolutely not. We've never seen any life on Earth that 453 00:22:22,359 --> 00:22:25,600 Speaker 1: doesn't use carbon. And you're saying it's because carbon has 454 00:22:25,640 --> 00:22:28,320 Speaker 1: something unique about it. What is it that's unique about it? 455 00:22:28,400 --> 00:22:31,480 Speaker 1: Like it has its electrons or the right number of 456 00:22:31,480 --> 00:22:35,679 Speaker 1: electron orbitals, or the orbitals are a special precision. What 457 00:22:35,800 --> 00:22:38,239 Speaker 1: is it about carbon? Yeah, So the chemical properties of 458 00:22:38,280 --> 00:22:41,280 Speaker 1: any element are determined by like how many electrons it 459 00:22:41,320 --> 00:22:44,040 Speaker 1: has and how many empty slots it has in its 460 00:22:44,080 --> 00:22:47,240 Speaker 1: outermost ring, and carbon has just the right number that 461 00:22:47,280 --> 00:22:49,720 Speaker 1: it makes it easy to like stick them together, to 462 00:22:49,840 --> 00:22:52,520 Speaker 1: make these bonds in a useful way, and also to 463 00:22:52,520 --> 00:22:55,159 Speaker 1: stick other things onto it. So you can stick like 464 00:22:55,320 --> 00:22:59,119 Speaker 1: iron and magnesium and zinc and nitrogen onto these like 465 00:22:59,280 --> 00:23:02,480 Speaker 1: chains of carbons. Carbon is useful because you can stick 466 00:23:02,480 --> 00:23:04,280 Speaker 1: a couple of carbons together and still have room for 467 00:23:04,320 --> 00:23:06,120 Speaker 1: another one and another one, So it can make these 468 00:23:06,200 --> 00:23:08,400 Speaker 1: very long chains, and then you can have like other 469 00:23:08,440 --> 00:23:11,440 Speaker 1: elements stuck onto the side. It's not limited in that way. 470 00:23:11,720 --> 00:23:14,600 Speaker 1: Other elements like xeno and for example, all their orbitals 471 00:23:14,600 --> 00:23:17,080 Speaker 1: are just full, so they don't like to interact with anything. 472 00:23:17,240 --> 00:23:19,800 Speaker 1: And yet other elements you can stick them together in 473 00:23:19,840 --> 00:23:21,920 Speaker 1: a couple of ways, but they're sort of limited because 474 00:23:21,960 --> 00:23:24,000 Speaker 1: the number of the electrons they have free in their 475 00:23:24,000 --> 00:23:27,600 Speaker 1: outer orbital So carbon is just like a very versatile element, right, 476 00:23:27,640 --> 00:23:30,800 Speaker 1: it's versatile, But is there something unique about it that 477 00:23:30,880 --> 00:23:34,080 Speaker 1: lets you make complex molecules that can make complex molecules 478 00:23:34,080 --> 00:23:37,520 Speaker 1: out of something else or just not as well you're saying, 479 00:23:37,520 --> 00:23:39,439 Speaker 1: So it is possible. Actually, if you look through the 480 00:23:39,440 --> 00:23:43,480 Speaker 1: periodic table, there are other elements that have similar behaviors. 481 00:23:43,480 --> 00:23:46,200 Speaker 1: Silicon is the most famous example. You can also build 482 00:23:46,280 --> 00:23:49,359 Speaker 1: really long chains of itself, so you can get big, 483 00:23:49,440 --> 00:23:54,200 Speaker 1: complex molecules, molecules that can carry a lot of biological information. 484 00:23:54,240 --> 00:23:56,879 Speaker 1: And so it's been famously proposed that life elsewhere in 485 00:23:56,880 --> 00:24:00,160 Speaker 1: the universe might be made out of silicon. In out 486 00:24:00,200 --> 00:24:02,119 Speaker 1: of carbon. It's like an alternative, you know, it's like 487 00:24:02,200 --> 00:24:06,639 Speaker 1: do blow bricks instead of lego bricks the knockoff. But 488 00:24:07,000 --> 00:24:09,399 Speaker 1: I guess what's the difference between carbon and silicon. Do 489 00:24:09,480 --> 00:24:11,560 Speaker 1: they have the same number of electrons? Do they have 490 00:24:11,640 --> 00:24:15,080 Speaker 1: different you know, orbitals or atomic weight? Well, carbon is 491 00:24:15,160 --> 00:24:17,760 Speaker 1: much further down on the periodic table, right, it's element 492 00:24:17,840 --> 00:24:21,600 Speaker 1: number six, where silicon is fourteen. And so you might think, oh, well, 493 00:24:21,640 --> 00:24:24,199 Speaker 1: that makes carbon much more common in the universe and 494 00:24:24,240 --> 00:24:28,040 Speaker 1: therefore much more just likely to be useful for life. 495 00:24:28,480 --> 00:24:30,679 Speaker 1: And it's true the carbon is much more common in 496 00:24:30,720 --> 00:24:34,160 Speaker 1: the universe because remember where these elements come from. They 497 00:24:34,200 --> 00:24:36,879 Speaker 1: come from fusion at the hearts of stars. You start 498 00:24:36,880 --> 00:24:39,280 Speaker 1: with just hydrogen from the Big Bang, you stick it together, 499 00:24:39,359 --> 00:24:42,240 Speaker 1: you get helium. In the hearts of really really hot stars, 500 00:24:42,280 --> 00:24:44,320 Speaker 1: you can make carbon, and you build from there to 501 00:24:44,400 --> 00:24:47,439 Speaker 1: make the heavier elements. So in the broader universe, carbon 502 00:24:47,600 --> 00:24:50,000 Speaker 1: is much more common. There's like ten times as much 503 00:24:50,040 --> 00:24:53,359 Speaker 1: carbon in the universe as there is silicon. But actually 504 00:24:53,600 --> 00:24:58,000 Speaker 1: here on Earth, silicon is nine hundred times more common 505 00:24:58,119 --> 00:25:00,879 Speaker 1: in the Earth's crust then car been, so we're actually 506 00:25:00,880 --> 00:25:04,320 Speaker 1: sort of drowning in silicon here on Earth. But of 507 00:25:04,320 --> 00:25:07,280 Speaker 1: course our life is made out of carbon. So that 508 00:25:07,359 --> 00:25:10,440 Speaker 1: sort of suggests that like, carbon is much more useful, 509 00:25:10,520 --> 00:25:13,720 Speaker 1: it's much easier way to start life than silicon is. 510 00:25:13,800 --> 00:25:16,359 Speaker 1: Even though silicon is much more common here on Earth, 511 00:25:16,720 --> 00:25:19,880 Speaker 1: you're saying silicon has a higher etomic weight like it's heavier, 512 00:25:19,960 --> 00:25:22,800 Speaker 1: it has more protons and neutrons and the nucleus, and 513 00:25:22,880 --> 00:25:25,480 Speaker 1: does it also have more electrons and in its orbit, Yeah, 514 00:25:25,520 --> 00:25:28,040 Speaker 1: the neutral atom will have the same number of protons 515 00:25:28,080 --> 00:25:31,560 Speaker 1: and electrons. So carbon has six protons and silicon has 516 00:25:31,600 --> 00:25:35,480 Speaker 1: fourteen protons, which means it also has fourteen electrons. But 517 00:25:35,480 --> 00:25:38,560 Speaker 1: when't having more electrons give you more ways to like 518 00:25:38,680 --> 00:25:41,840 Speaker 1: interact or form bonds with other atoms. It's not just 519 00:25:41,880 --> 00:25:44,080 Speaker 1: the number of electrons in total, right, It depends on 520 00:25:44,119 --> 00:25:46,880 Speaker 1: the number of electrons, mostly in the outer layer, because 521 00:25:46,920 --> 00:25:49,040 Speaker 1: those are the ones that do the interacting. When you 522 00:25:49,080 --> 00:25:51,920 Speaker 1: click elements together, you do it by having their outer 523 00:25:52,040 --> 00:25:55,960 Speaker 1: shells interact. Electrons don't really go deeper into the lower shells. 524 00:25:56,040 --> 00:25:57,679 Speaker 1: That really just has to do with how many you 525 00:25:57,760 --> 00:25:59,960 Speaker 1: have free in the outer shells that like, you click 526 00:26:00,119 --> 00:26:03,640 Speaker 1: these things together like lego bricks, right, And silicon can't 527 00:26:03,880 --> 00:26:06,639 Speaker 1: form bonds with other important atoms, right, that's one of 528 00:26:06,640 --> 00:26:09,320 Speaker 1: its problems. Yeah, So carbon is really cool because it 529 00:26:09,400 --> 00:26:12,440 Speaker 1: can easily make bonds with like phosphorus and sulfur and metals, 530 00:26:12,440 --> 00:26:15,800 Speaker 1: And while silicon can make long chains of itself, it's 531 00:26:15,840 --> 00:26:19,600 Speaker 1: not as good at connecting with these other kinds of things, 532 00:26:19,680 --> 00:26:22,479 Speaker 1: and so like oxygen and nitrogen phosphorus, it's not so 533 00:26:22,560 --> 00:26:26,280 Speaker 1: easy to build like biochemical molecules with all these other 534 00:26:26,320 --> 00:26:29,199 Speaker 1: little bits in it out of silicon than carbon. So 535 00:26:29,320 --> 00:26:32,640 Speaker 1: from that perspective, carbon is a better choice for making 536 00:26:32,680 --> 00:26:36,120 Speaker 1: a diversity of chemical combinations. I see, I think you're 537 00:26:36,119 --> 00:26:38,800 Speaker 1: saying that it's it's still possible to make life with silicon, 538 00:26:39,040 --> 00:26:41,879 Speaker 1: but maybe because it's not as versatile, you couldn't maybe 539 00:26:41,960 --> 00:26:44,560 Speaker 1: do as maybe neat tricks with the with your molecules 540 00:26:44,600 --> 00:26:46,479 Speaker 1: as you could with carbon, which maybe it would make 541 00:26:46,520 --> 00:26:48,960 Speaker 1: it harder to kind of evolve life. I imagine it 542 00:26:49,040 --> 00:26:51,680 Speaker 1: might make it harder. There's certainly fewer things you can 543 00:26:51,760 --> 00:26:55,439 Speaker 1: do with silicon than carbon. Though, actually being prevented from 544 00:26:55,520 --> 00:26:58,480 Speaker 1: like latching onto all these weird other things can also 545 00:26:58,600 --> 00:27:02,119 Speaker 1: protect life. Right For example, the basic building blocks of 546 00:27:02,160 --> 00:27:05,800 Speaker 1: your life can't grab onto heavy metals magnesium and zinc, 547 00:27:06,000 --> 00:27:08,720 Speaker 1: then you're sort of shielded from some of those impurities 548 00:27:09,040 --> 00:27:12,400 Speaker 1: because they don't engage with your biochemistry. So like silicon 549 00:27:12,440 --> 00:27:16,640 Speaker 1: based life might be more protected from heavy metals, for example, 550 00:27:16,760 --> 00:27:20,640 Speaker 1: whereas we find like mercury and lead poisonous in our biochemistry. 551 00:27:20,680 --> 00:27:22,800 Speaker 1: So there's sort of a pro andacon there. And as 552 00:27:22,840 --> 00:27:26,000 Speaker 1: you said, there's much more silicon here on Earth than carbon, 553 00:27:26,080 --> 00:27:29,760 Speaker 1: and yet life chose carbon as its building ball. Yeah, exactly, 554 00:27:30,080 --> 00:27:32,840 Speaker 1: And so even though there's more carbon in the universe 555 00:27:33,000 --> 00:27:35,159 Speaker 1: here on Earth, we don't have like an average scoop 556 00:27:35,240 --> 00:27:38,439 Speaker 1: of the universe stuff. Right, Hydrogen is the most common 557 00:27:38,480 --> 00:27:40,679 Speaker 1: thing in the universe by far, but we don't have 558 00:27:40,800 --> 00:27:43,200 Speaker 1: very much hydrogen here on Earth because it was mostly 559 00:27:43,240 --> 00:27:45,879 Speaker 1: gobbled up by the Sun and by Jupiter. So the 560 00:27:45,920 --> 00:27:47,960 Speaker 1: process that formed the Earth didn't get like an equal 561 00:27:47,960 --> 00:27:51,520 Speaker 1: sampling of everything. And especially here on the crust, there's 562 00:27:51,520 --> 00:27:54,200 Speaker 1: a lot more silicon. We think that the carbon based 563 00:27:54,240 --> 00:27:57,040 Speaker 1: molecules were more volatile and they sort of like boiled 564 00:27:57,080 --> 00:28:00,119 Speaker 1: away early on. And so you're right, even though we 565 00:28:00,160 --> 00:28:03,200 Speaker 1: have more silicon than carbon, we ended up making life 566 00:28:03,200 --> 00:28:05,760 Speaker 1: out of carbon. And that's just you know, one example. 567 00:28:05,800 --> 00:28:07,960 Speaker 1: We don't know if that's typical, if it's common, if 568 00:28:08,000 --> 00:28:11,280 Speaker 1: everywhere life will start from carbon, it might be unusual. 569 00:28:11,280 --> 00:28:13,160 Speaker 1: It might been like a single flash in the pan. 570 00:28:13,359 --> 00:28:16,160 Speaker 1: So it's carbon super unique to make life, or can 571 00:28:16,240 --> 00:28:20,879 Speaker 1: physicists and chemists imagine using another atom to make life 572 00:28:20,920 --> 00:28:23,040 Speaker 1: like I know, silicon, Maybe it's not a great candidate, 573 00:28:23,080 --> 00:28:24,960 Speaker 1: but are there others? There are not a lot of 574 00:28:24,960 --> 00:28:27,600 Speaker 1: other great candidates in terms of replacements for carbon. It's 575 00:28:27,600 --> 00:28:30,919 Speaker 1: basically silicon or nothing. Oh wow, So if there is 576 00:28:31,040 --> 00:28:34,479 Speaker 1: life out there in the universe, it's probably carbon too, right, 577 00:28:34,560 --> 00:28:37,960 Speaker 1: probably carbon or silicon or weirder than anything we have 578 00:28:38,000 --> 00:28:41,040 Speaker 1: imagined so far, which could be very unlikely or very 579 00:28:41,120 --> 00:28:44,360 Speaker 1: very common. What do you mean, we're like it uses um, 580 00:28:44,400 --> 00:28:47,800 Speaker 1: I don't know that titanium. Well, we're starting from some 581 00:28:47,880 --> 00:28:52,400 Speaker 1: assumptions that the biochemical processes and information storage that's part 582 00:28:52,480 --> 00:28:55,440 Speaker 1: of our life will be necessary for other kinds of life. 583 00:28:55,480 --> 00:28:57,760 Speaker 1: And maybe that's not true, and so maybe there's a 584 00:28:57,760 --> 00:29:01,720 Speaker 1: completely different way to organize self sustaining information. You know, 585 00:29:01,840 --> 00:29:05,440 Speaker 1: loops of plasma currents inside of stars that can just 586 00:29:05,480 --> 00:29:07,880 Speaker 1: be made out of hydrogen, for example, where the complexity 587 00:29:07,920 --> 00:29:11,360 Speaker 1: comes from, you know, the structure of the plasma instead 588 00:29:11,400 --> 00:29:13,640 Speaker 1: of the structure of the atoms that you're making out 589 00:29:13,640 --> 00:29:16,080 Speaker 1: of heavier elements. We don't know what we haven't yet 590 00:29:16,080 --> 00:29:19,440 Speaker 1: imagined about the ways that life can be, right, right, 591 00:29:19,480 --> 00:29:21,640 Speaker 1: I wonder if like all life and the universe being 592 00:29:21,640 --> 00:29:24,200 Speaker 1: made out of carbon means that we're more likely to 593 00:29:24,240 --> 00:29:27,680 Speaker 1: be eaten by aliens. We're more likely to be edible 594 00:29:27,760 --> 00:29:30,800 Speaker 1: to aliens. Yeah, absolutely, that's what I mean. We know, 595 00:29:30,960 --> 00:29:33,400 Speaker 1: I mean, we're all, you know, tasty to each other. Perhaps, 596 00:29:33,840 --> 00:29:35,959 Speaker 1: all right, well, let's tackle some of the other ingredients 597 00:29:36,000 --> 00:29:37,840 Speaker 1: of life. What if we had all of the ingredients 598 00:29:37,880 --> 00:29:41,000 Speaker 1: of life except another one of these crucial ones, water, Like, 599 00:29:41,040 --> 00:29:42,920 Speaker 1: what would happen if we didn't have water. It's a 600 00:29:42,920 --> 00:29:45,720 Speaker 1: great question, and maybe not a necessary one because remember 601 00:29:45,760 --> 00:29:49,440 Speaker 1: that like water is everywhere in the universe. It's not 602 00:29:49,480 --> 00:29:52,040 Speaker 1: like water is that hard to find. I know, on 603 00:29:52,160 --> 00:29:54,840 Speaker 1: space operas they are always talking about finding water and 604 00:29:54,880 --> 00:29:57,280 Speaker 1: selling water. But you know, we have like whole planets 605 00:29:57,280 --> 00:29:59,840 Speaker 1: of water out there, Neptune and Uranus. They're called ice 606 00:30:00,040 --> 00:30:02,720 Speaker 1: giants for a reason. There really is a lot of 607 00:30:02,800 --> 00:30:05,800 Speaker 1: water out there in the universe. But anyway, it's fun 608 00:30:05,840 --> 00:30:09,200 Speaker 1: to think about where life might start if there isn't 609 00:30:09,280 --> 00:30:12,320 Speaker 1: much water around. You know, for example, there are moons 610 00:30:12,360 --> 00:30:15,400 Speaker 1: of Jupiter and Saturn that have oceans that could be 611 00:30:15,640 --> 00:30:19,080 Speaker 1: made out of other kinds of liquids ammonia for example, 612 00:30:19,160 --> 00:30:21,280 Speaker 1: or methane, And so it's fun to think about whether 613 00:30:21,360 --> 00:30:24,160 Speaker 1: or not you could have life that uses other solvents. Right. 614 00:30:24,200 --> 00:30:27,040 Speaker 1: The role of water in life basically is to dissolve 615 00:30:27,080 --> 00:30:30,800 Speaker 1: stuff so that things can slosh around in exchange. It's 616 00:30:30,800 --> 00:30:33,600 Speaker 1: hard to have life if everything is like a solid crystal, 617 00:30:33,800 --> 00:30:37,040 Speaker 1: because then they can't like exchange information and transfer energy. 618 00:30:37,280 --> 00:30:40,200 Speaker 1: You need some flow, some movement so that energy and 619 00:30:40,240 --> 00:30:42,840 Speaker 1: information can sort of move around and make things happen. 620 00:30:42,960 --> 00:30:44,840 Speaker 1: It's like you need it as a medium, right, not 621 00:30:45,000 --> 00:30:47,840 Speaker 1: just for life to develop in and for like books 622 00:30:47,840 --> 00:30:50,360 Speaker 1: to move around in, but also like inside of our bodies, 623 00:30:50,360 --> 00:30:53,000 Speaker 1: you need water so that you can circulate stuff, right, 624 00:30:53,080 --> 00:30:55,360 Speaker 1: and ions can move from one place to the other. Yeah, 625 00:30:55,400 --> 00:30:58,120 Speaker 1: you need these basic processes to happen, and so you 626 00:30:58,160 --> 00:31:00,440 Speaker 1: need some kind of flow. Just like if you have 627 00:31:00,440 --> 00:31:02,880 Speaker 1: a party but nobody's talking to each other, then nothing's 628 00:31:02,920 --> 00:31:05,240 Speaker 1: really going on. And so to get the party started, 629 00:31:05,320 --> 00:31:08,640 Speaker 1: you need some way for these bits and pieces to interact, 630 00:31:08,720 --> 00:31:10,760 Speaker 1: and the best way we know is to dissolve them 631 00:31:10,760 --> 00:31:12,560 Speaker 1: all in water, and then they can just sort of 632 00:31:12,560 --> 00:31:15,360 Speaker 1: slash around. When they bump into each other, good stuff happens. 633 00:31:15,520 --> 00:31:18,160 Speaker 1: And so people have thought about whether this is possible 634 00:31:18,320 --> 00:31:22,040 Speaker 1: in other kinds of chemicals, and one fun alternative is ammonia. 635 00:31:22,080 --> 00:31:25,400 Speaker 1: Ammonia is also fairly common in the universe, and like water, 636 00:31:25,520 --> 00:31:29,280 Speaker 1: it's liquid over a large temperature range and can also 637 00:31:29,440 --> 00:31:34,080 Speaker 1: dissolve a wide variety of compounds. Wait, so do all 638 00:31:34,240 --> 00:31:37,200 Speaker 1: life on Earth as we know it use water as 639 00:31:37,240 --> 00:31:38,960 Speaker 1: its basis? Do we know? But any other life that 640 00:31:39,000 --> 00:31:41,080 Speaker 1: doesn't use water. We don't know of any life that 641 00:31:41,080 --> 00:31:43,720 Speaker 1: doesn't use water. It's all water based, and you know, 642 00:31:43,760 --> 00:31:47,560 Speaker 1: the basic cell has water inside of it. Life basically 643 00:31:47,680 --> 00:31:51,200 Speaker 1: is a bag of water with other stuff dissolved into it. 644 00:31:51,600 --> 00:31:53,520 Speaker 1: But how don't they found bacteria and like, you know, 645 00:31:53,640 --> 00:31:57,080 Speaker 1: sulfur pools and you know, at the bottom of volcanoes 646 00:31:57,080 --> 00:32:00,000 Speaker 1: and things like that, they have found bacteria basically every 647 00:32:00,080 --> 00:32:03,520 Speaker 1: were but they are all little bags of water. Okay, 648 00:32:03,520 --> 00:32:07,120 Speaker 1: So then ammonia is interesting because it's also a liquid. 649 00:32:07,280 --> 00:32:10,680 Speaker 1: And what's the chemical formula for ammonia. Ammonia is n 650 00:32:10,920 --> 00:32:14,200 Speaker 1: H three, so it's nitrogen and three hydrogens. And you know, 651 00:32:14,240 --> 00:32:16,840 Speaker 1: there's plenty of hydrogen out there in the universe, and 652 00:32:16,960 --> 00:32:19,760 Speaker 1: nitrogen is also not that rare, although it's not as 653 00:32:19,800 --> 00:32:22,479 Speaker 1: common as oxygen. But there's plenty of ammonia out there 654 00:32:22,480 --> 00:32:24,280 Speaker 1: in the universe. Okay, So then out of all the 655 00:32:24,360 --> 00:32:27,000 Speaker 1: liquids out there that could form the basis of life, 656 00:32:27,160 --> 00:32:31,480 Speaker 1: why is ammonia better or a candidate than everything else, 657 00:32:31,520 --> 00:32:33,200 Speaker 1: but maybe not as good as water. Well, it's a 658 00:32:33,200 --> 00:32:35,520 Speaker 1: good candidate because it has some of the same properties 659 00:32:35,560 --> 00:32:38,920 Speaker 1: as water, meaning that it's liquid in a large temperature range. 660 00:32:39,160 --> 00:32:41,480 Speaker 1: For life to happen in ammonia, you need ammonia to 661 00:32:41,560 --> 00:32:44,200 Speaker 1: be liquid. To be liquid, so for this to be likely, 662 00:32:44,600 --> 00:32:47,920 Speaker 1: you wanted to not have to have very special circumstances, 663 00:32:48,440 --> 00:32:50,920 Speaker 1: and so, like water has a hundred celsius degrees in 664 00:32:50,960 --> 00:32:54,920 Speaker 1: which it's liquid, ammonia also has a pretty broad range. 665 00:32:55,280 --> 00:32:58,760 Speaker 1: It's liquid from negative seventy eight to negative thirty three C. 666 00:33:00,040 --> 00:33:03,480 Speaker 1: There are other liquids that are liquid over a wide range. 667 00:33:03,600 --> 00:33:06,240 Speaker 1: What makes ammonia special, Well, ammonia can dissolve a bunch 668 00:33:06,240 --> 00:33:10,120 Speaker 1: of stuff. Also, ammonia has a large heat of vaporization. 669 00:33:10,440 --> 00:33:12,600 Speaker 1: That means if you have like a lake of the stuff, 670 00:33:12,920 --> 00:33:16,520 Speaker 1: it's harder for it to just like evaporate into the atmosphere. 671 00:33:17,040 --> 00:33:20,479 Speaker 1: And we think that probably life formed in like lakes 672 00:33:20,520 --> 00:33:23,880 Speaker 1: and oceans, maybe brackish water where like waves were lapping 673 00:33:23,960 --> 00:33:26,360 Speaker 1: up and mixing stuff around. So you need sort of 674 00:33:26,400 --> 00:33:29,120 Speaker 1: like stable pools of this liquid for life to form. 675 00:33:29,240 --> 00:33:32,320 Speaker 1: And ammonia, like water, has this large heat of vaporization 676 00:33:32,360 --> 00:33:36,160 Speaker 1: takes a lot of energy to evaporate it into the atmosphere. Interesting, 677 00:33:36,160 --> 00:33:38,720 Speaker 1: why is that? Why does water an ammonia have this property. 678 00:33:38,760 --> 00:33:41,479 Speaker 1: So it's getting deep into chemistry territory, which is not 679 00:33:41,520 --> 00:33:43,480 Speaker 1: my expertise, but I think it has to do with 680 00:33:43,520 --> 00:33:47,040 Speaker 1: the intermolecular forces. Basically, how hard is it to pull 681 00:33:47,080 --> 00:33:49,320 Speaker 1: these things apart. Each of these atoms are pretty stable, 682 00:33:49,320 --> 00:33:51,800 Speaker 1: but they're also a little bit sticky. When they get 683 00:33:51,800 --> 00:33:54,240 Speaker 1: near each other, they like to clump together. And so 684 00:33:54,360 --> 00:33:56,720 Speaker 1: this just depends on how much energy it takes to 685 00:33:56,840 --> 00:33:59,720 Speaker 1: pull the individual molecules apart to change it from a 686 00:33:59,800 --> 00:34:02,360 Speaker 1: lick wid into a gas, and that depends on the 687 00:34:02,400 --> 00:34:05,560 Speaker 1: details of the chemical structure. Yeah, I guess if you 688 00:34:05,600 --> 00:34:07,880 Speaker 1: had like a large lake of alcohol, it would just 689 00:34:07,960 --> 00:34:11,799 Speaker 1: evaporate pretty quickly, exactly. So for different chemicals, either you 690 00:34:11,800 --> 00:34:14,000 Speaker 1: need a lot of energy to evaporate them or not 691 00:34:14,200 --> 00:34:16,800 Speaker 1: very much. And so for ammonia you have a fairly 692 00:34:16,880 --> 00:34:19,640 Speaker 1: large heated vaporization, though not as big as for water. 693 00:34:19,800 --> 00:34:22,920 Speaker 1: So water sort of better at forming big stable pools 694 00:34:22,920 --> 00:34:25,040 Speaker 1: than ammonia is. All right, So ammonia it might be 695 00:34:25,080 --> 00:34:28,040 Speaker 1: a good replacement for water, But life on Earth didn't 696 00:34:28,120 --> 00:34:31,240 Speaker 1: use ammonia. Why aren't there any ammonia based life forms 697 00:34:31,360 --> 00:34:33,399 Speaker 1: on Earth. Well, again, we don't know. It's just luck. 698 00:34:33,520 --> 00:34:36,279 Speaker 1: But water does have some advantages that ammonia doesn't have. 699 00:34:36,400 --> 00:34:40,080 Speaker 1: For example, ice floats on liquid water. When you freeze water, 700 00:34:40,160 --> 00:34:43,640 Speaker 1: it actually grows in volume, so it's density drops, which 701 00:34:43,680 --> 00:34:45,759 Speaker 1: is why lakes, for example, in the winter, freeze from 702 00:34:45,800 --> 00:34:49,080 Speaker 1: the top down. The liquid water can stay underneath, and 703 00:34:49,120 --> 00:34:52,920 Speaker 1: like fishes and microbes or whatever can sometimes survive through 704 00:34:52,920 --> 00:34:55,640 Speaker 1: the winter under the ice, whereas that would be trickier 705 00:34:55,640 --> 00:34:58,000 Speaker 1: if they froze all at once, for example. And so 706 00:34:58,120 --> 00:35:01,440 Speaker 1: this very strange property of water allows it to float 707 00:35:01,640 --> 00:35:05,840 Speaker 1: on liquid water, and that doesn't happen for ammonia for example. Also, 708 00:35:05,920 --> 00:35:09,560 Speaker 1: water is stable in the presence of oxygen. A lot 709 00:35:09,600 --> 00:35:11,680 Speaker 1: of things out there, when you put them near oxygen, 710 00:35:11,920 --> 00:35:15,399 Speaker 1: they can combust, right, they can burn, or they can oxydize. 711 00:35:15,560 --> 00:35:18,000 Speaker 1: The water is actually stable in the presence of oxygen 712 00:35:18,200 --> 00:35:21,840 Speaker 1: because it's actually the product of combustion. You take hydrogen 713 00:35:21,920 --> 00:35:25,240 Speaker 1: and oxygen together and you light a match, you get water, 714 00:35:25,800 --> 00:35:28,120 Speaker 1: And so water is stable in the presence of oxygen, 715 00:35:28,160 --> 00:35:30,400 Speaker 1: which is nice if you want to have oxygen in 716 00:35:30,440 --> 00:35:33,600 Speaker 1: your atmosphere and not have it beyond fire all the time. Right. Also, 717 00:35:33,640 --> 00:35:36,839 Speaker 1: I imagine water is much more abundant here on Earth, right, 718 00:35:36,880 --> 00:35:39,480 Speaker 1: Like we don't have large lakes of ammonia, but we 719 00:35:39,520 --> 00:35:41,680 Speaker 1: do have a whole ocean of water. We certainly have 720 00:35:41,719 --> 00:35:44,640 Speaker 1: a lot more water than ammonia. In other places in 721 00:35:44,680 --> 00:35:47,720 Speaker 1: the Solar system there are lakes of ammonia or methane 722 00:35:47,800 --> 00:35:50,279 Speaker 1: for example. Is it also sort of a property of 723 00:35:50,280 --> 00:35:54,399 Speaker 1: its solvent but properties you know, like maybe like if 724 00:35:54,400 --> 00:35:56,560 Speaker 1: you try to grow something in kerosene, it which is 725 00:35:56,719 --> 00:36:00,759 Speaker 1: can dissolve and and die. Is it water like soluble 726 00:36:00,800 --> 00:36:04,000 Speaker 1: but not too soluble. They're both really good at being solvents. 727 00:36:04,000 --> 00:36:06,680 Speaker 1: But one disadvantage for ammonia is that it's liquid at 728 00:36:06,719 --> 00:36:10,680 Speaker 1: lower temperatures, right like negative seventy eight negative thirty three C. 729 00:36:11,280 --> 00:36:13,560 Speaker 1: That means if you have life that's ammonia based, it's 730 00:36:13,600 --> 00:36:16,280 Speaker 1: going to move slower, It's going to evolve more slowly. 731 00:36:16,320 --> 00:36:19,160 Speaker 1: Like the whole time scale for things to happen is 732 00:36:19,200 --> 00:36:21,840 Speaker 1: going to be slower just because things are colder. So 733 00:36:21,960 --> 00:36:25,800 Speaker 1: water based life might just like outpace and outrace ammonia 734 00:36:25,840 --> 00:36:29,120 Speaker 1: based life. Interesting, So it is possible for life out 735 00:36:29,200 --> 00:36:31,799 Speaker 1: there in the universe to be ammonia base. If there's 736 00:36:31,840 --> 00:36:34,040 Speaker 1: a planet where there's no water, but there is there 737 00:36:34,080 --> 00:36:36,839 Speaker 1: are oceans of ammonia, maybe life could develop there. Yeah, 738 00:36:36,880 --> 00:36:39,360 Speaker 1: it seems like it's totally possible. Yeah, And so they 739 00:36:39,360 --> 00:36:42,799 Speaker 1: would be drinking a glassful of ammonia every day. They 740 00:36:42,880 --> 00:36:46,040 Speaker 1: might think that water stinks, right, maybe they use it 741 00:36:46,080 --> 00:36:50,200 Speaker 1: to clean all right. The last ingredient that Christian mentioned 742 00:36:50,239 --> 00:36:53,640 Speaker 1: was oxygen. Do if you lose oxygen, can you still 743 00:36:53,680 --> 00:36:56,120 Speaker 1: have life? And it seems like oxen it's part of 744 00:36:56,120 --> 00:36:58,719 Speaker 1: water too, So I guess the questions are kind of related. Yeah, 745 00:36:58,760 --> 00:37:01,200 Speaker 1: I suppose. So oxygen is a part of water that's 746 00:37:01,239 --> 00:37:02,959 Speaker 1: not a part of ammonia. But when you think about 747 00:37:02,960 --> 00:37:06,720 Speaker 1: oxygen life, you're mostly thinking about breathing oxygen, like atmospheric 748 00:37:06,719 --> 00:37:10,200 Speaker 1: oxygen O two within the atmosphere that you pass through 749 00:37:10,239 --> 00:37:13,759 Speaker 1: your lungs and that many many things on Earth rely on. 750 00:37:14,440 --> 00:37:17,360 Speaker 1: And we often think about oxygen is like a biosignature. 751 00:37:17,640 --> 00:37:20,440 Speaker 1: We're looking on other planets to see if there's maybe 752 00:37:20,480 --> 00:37:22,799 Speaker 1: life in their atmosphere. We're checking out to see if 753 00:37:22,800 --> 00:37:25,600 Speaker 1: there's oxygen there. Like, are you saying, if we had 754 00:37:26,000 --> 00:37:29,560 Speaker 1: maybe water and carbon but not a lot of oxygen gas, 755 00:37:29,600 --> 00:37:31,440 Speaker 1: could you still have life or what would you used 756 00:37:31,440 --> 00:37:33,600 Speaker 1: to replace oxygen? Yeah? And it turns out you actually 757 00:37:33,640 --> 00:37:36,560 Speaker 1: don't need oxygen, and we didn't have oxygen here on 758 00:37:36,680 --> 00:37:42,160 Speaker 1: Earth when life evolved. Oxygen itself is a product of photosynthesis. 759 00:37:42,600 --> 00:37:44,759 Speaker 1: So life started here on Earth when there was no 760 00:37:44,840 --> 00:37:48,640 Speaker 1: oxygen in the atmosphere. It was ani aerobic to begin with. Right. 761 00:37:48,680 --> 00:37:52,319 Speaker 1: There are bacterias that grow without any oxygen, right, Yeah, 762 00:37:52,400 --> 00:37:55,160 Speaker 1: Like the bacteria in your gut are mostly ania aerobic 763 00:37:55,200 --> 00:37:58,040 Speaker 1: microbes because there isn't a whole lot of oxygen in there. Right, 764 00:37:58,560 --> 00:38:01,319 Speaker 1: But eventually life produced to oxygen and that's what we 765 00:38:01,520 --> 00:38:04,040 Speaker 1: require right now, So what is oxygen good for them? 766 00:38:04,080 --> 00:38:07,480 Speaker 1: So oxygen was originally a waste product? Right, Microbes learned 767 00:38:07,600 --> 00:38:12,240 Speaker 1: to do photosynthesis and oxygen is the byproduct of photosynthesis. 768 00:38:12,239 --> 00:38:15,120 Speaker 1: It's just like their garbage. And it turns out that 769 00:38:15,280 --> 00:38:19,080 Speaker 1: some kinds of metabolisms that involve oxygen are much more 770 00:38:19,120 --> 00:38:22,400 Speaker 1: efficient than the anaerobic ways, and so a bunch of 771 00:38:22,440 --> 00:38:24,920 Speaker 1: other microbes figured out how to take advantage of that 772 00:38:24,960 --> 00:38:27,880 Speaker 1: waste product and use it to make themselves more efficient. 773 00:38:28,000 --> 00:38:31,839 Speaker 1: So it's sort of like supercharges life's metabolisms. And that's 774 00:38:31,880 --> 00:38:34,720 Speaker 1: just like a lesson about microbes. Microbes will always figure 775 00:38:34,760 --> 00:38:37,200 Speaker 1: out how to use someone else's garbage and turn it 776 00:38:37,200 --> 00:38:40,080 Speaker 1: into their food. It sounds like it's super charges life. 777 00:38:40,120 --> 00:38:43,279 Speaker 1: So could you have complex life or life as we 778 00:38:43,320 --> 00:38:45,680 Speaker 1: know it without oxygen? We don't know. We didn't have 779 00:38:45,719 --> 00:38:48,799 Speaker 1: a lot of atmospheric oxygen on Earth until about eight 780 00:38:48,840 --> 00:38:52,480 Speaker 1: hundred and fifty million years ago, and that's also about 781 00:38:52,520 --> 00:38:55,080 Speaker 1: when things started to get much more complicated. So it's 782 00:38:55,160 --> 00:38:58,360 Speaker 1: possible that you sort of need oxygen or something similar 783 00:38:58,640 --> 00:39:00,920 Speaker 1: to supercharge and metable is M and allow things to 784 00:39:00,920 --> 00:39:03,279 Speaker 1: get complicated, or it's possible that it would have done 785 00:39:03,280 --> 00:39:06,279 Speaker 1: it without oxygen. We only really have this one experiment, 786 00:39:06,360 --> 00:39:08,319 Speaker 1: so we don't know. If we didn't have it, could 787 00:39:08,320 --> 00:39:10,640 Speaker 1: you replace it, or you know, if we didn't have 788 00:39:10,680 --> 00:39:13,719 Speaker 1: those victoria making it and you wanted to supercharge life, 789 00:39:13,800 --> 00:39:16,400 Speaker 1: there's something else you could use. Oxygen is pretty special 790 00:39:16,480 --> 00:39:18,840 Speaker 1: because it's so reactive, and it's very good at like 791 00:39:18,880 --> 00:39:22,080 Speaker 1: accepting electrons at the end of this metabolism cycle. But 792 00:39:22,080 --> 00:39:24,160 Speaker 1: there are other things you can do. People think that 793 00:39:24,200 --> 00:39:27,640 Speaker 1: like sulfur, for example, could also serve as part of 794 00:39:27,640 --> 00:39:31,760 Speaker 1: the like respiration process for alien life. Though nothing really 795 00:39:31,800 --> 00:39:34,640 Speaker 1: is as good as oxygen. Right, It's probably won't smell 796 00:39:34,640 --> 00:39:39,640 Speaker 1: as good. We're talking about aliens sipping ammonia and smelling 797 00:39:39,680 --> 00:39:42,360 Speaker 1: like sulfur, smelling like ron eggs. All right, well, I 798 00:39:42,360 --> 00:39:45,120 Speaker 1: think that answers christians question, which is that if you 799 00:39:45,200 --> 00:39:48,560 Speaker 1: lose anyone in your life team, it'd be pretty hard 800 00:39:48,600 --> 00:39:50,640 Speaker 1: to replace them. It seems like that you could try, 801 00:39:50,680 --> 00:39:54,480 Speaker 1: but you probably won't win the World Series. We don't 802 00:39:54,520 --> 00:39:56,759 Speaker 1: know if you'll be as competitive. But then again, we're 803 00:39:56,800 --> 00:39:59,000 Speaker 1: just looking at the one example we have here, and 804 00:39:59,040 --> 00:40:01,960 Speaker 1: we don't know, i this is the one lucky time 805 00:40:02,040 --> 00:40:04,480 Speaker 1: that the Twins actually win the World Series, or if 806 00:40:04,560 --> 00:40:06,799 Speaker 1: this is a pretty typical example out there. And in 807 00:40:06,840 --> 00:40:09,319 Speaker 1: the meantime, we'll just assume Christian looks like bread Pitt, 808 00:40:09,600 --> 00:40:12,200 Speaker 1: or maybe Christian is bread Pint. All right, let's get 809 00:40:12,200 --> 00:40:14,480 Speaker 1: to our last question of the day. But first let's 810 00:40:14,520 --> 00:40:30,160 Speaker 1: take another quick break. Okay, we are answering listener questions, 811 00:40:30,160 --> 00:40:32,879 Speaker 1: and we've answered awesome questions about how do you see 812 00:40:32,920 --> 00:40:36,319 Speaker 1: photons moving away? And also what would happen if you 813 00:40:36,360 --> 00:40:38,799 Speaker 1: lose some of the ingredients for life here on Earth. 814 00:40:38,880 --> 00:40:42,239 Speaker 1: Our last question here is about the red shifting of 815 00:40:42,360 --> 00:40:45,640 Speaker 1: light and it comes from Josh hid Daniel and Jorgey. 816 00:40:46,000 --> 00:40:49,759 Speaker 1: I had a question about red shifted photons. I was 817 00:40:49,840 --> 00:40:53,480 Speaker 1: just wondering how we can always tell the difference between 818 00:40:53,520 --> 00:40:58,200 Speaker 1: a photon that's been red shifted versus it just started 819 00:40:58,200 --> 00:41:00,680 Speaker 1: out more red. A few good day again into that 820 00:41:00,680 --> 00:41:03,480 Speaker 1: that'd be great. Thanks to keep up the good work alright. 821 00:41:03,520 --> 00:41:06,359 Speaker 1: Awesome question here from Josh. I think his question is 822 00:41:06,440 --> 00:41:11,000 Speaker 1: how do you tell what color a photon was originally? Like, 823 00:41:11,160 --> 00:41:13,960 Speaker 1: was it made a certain color or if it was 824 00:41:14,400 --> 00:41:16,640 Speaker 1: stretched to a certain color, And the answer is that 825 00:41:16,680 --> 00:41:19,480 Speaker 1: we can't. All we can do is measure the energy 826 00:41:19,520 --> 00:41:22,600 Speaker 1: of a photon. Measure its wavelength or its frequency, those 827 00:41:22,600 --> 00:41:25,480 Speaker 1: are all equivalent. Those determine how much energy it has. 828 00:41:25,760 --> 00:41:27,840 Speaker 1: So when a photon arrives on our sensors, we measure 829 00:41:27,840 --> 00:41:29,680 Speaker 1: its energy and then we can say, oh, this photon 830 00:41:29,719 --> 00:41:32,399 Speaker 1: has a certain frequency or a certain wavelength and that's 831 00:41:32,440 --> 00:41:35,920 Speaker 1: technically all we can know just from the photon itself, 832 00:41:36,360 --> 00:41:39,160 Speaker 1: from context, from where it came from, from all the 833 00:41:39,200 --> 00:41:42,080 Speaker 1: neighboring photons that arrives with, we might be able to 834 00:41:42,160 --> 00:41:45,440 Speaker 1: deduce something about his history. But directly, all we can 835 00:41:45,480 --> 00:41:48,759 Speaker 1: ever measure is the photon's current energy. We can't ever 836 00:41:48,840 --> 00:41:52,360 Speaker 1: really measure its past energy. Really, so there's no difference 837 00:41:52,360 --> 00:41:55,840 Speaker 1: between a photon that's been stretched to be read and 838 00:41:55,960 --> 00:41:59,200 Speaker 1: one that was made red. Yeah, quantum particles are very 839 00:41:59,239 --> 00:42:01,959 Speaker 1: simple in some way. They have a list of properties 840 00:42:02,360 --> 00:42:04,839 Speaker 1: and that's it. And two photons that have the same 841 00:42:04,960 --> 00:42:07,799 Speaker 1: energy and are going in the same direction are identical, right, 842 00:42:07,840 --> 00:42:10,040 Speaker 1: There's no difference to them. They don't even really have 843 00:42:10,080 --> 00:42:13,160 Speaker 1: an identity. You can't like say this one's Fred photon 844 00:42:13,239 --> 00:42:16,040 Speaker 1: and then that one's Maria photon. Really no difference. They're 845 00:42:16,080 --> 00:42:19,359 Speaker 1: just like ripples in the larger field that they're all 846 00:42:19,440 --> 00:42:21,960 Speaker 1: part of. Anyway, isn't there another I don't know, a 847 00:42:22,160 --> 00:42:24,200 Speaker 1: component to a photon that might be able to tell 848 00:42:24,239 --> 00:42:25,920 Speaker 1: you something like, you know, if I take a photon 849 00:42:25,960 --> 00:42:28,640 Speaker 1: and I stretch it so that it's red, when I 850 00:42:28,719 --> 00:42:31,560 Speaker 1: lose some overall energy or something, it's supposed to maybe 851 00:42:31,560 --> 00:42:34,960 Speaker 1: making a red photon that's really energetic. Then you could say, oh, 852 00:42:35,000 --> 00:42:38,200 Speaker 1: this one's really energetic, this one's low energy, maybe this 853 00:42:38,239 --> 00:42:41,160 Speaker 1: one was stretched. Well, the energy determines the color, and 854 00:42:41,200 --> 00:42:43,880 Speaker 1: so two photons that are like the same redness have 855 00:42:44,120 --> 00:42:46,880 Speaker 1: the same energy, So you can't tell if one of 856 00:42:46,920 --> 00:42:50,560 Speaker 1: them earlier had more energy and then got stretched to 857 00:42:50,719 --> 00:42:52,920 Speaker 1: lower energy, and you might wonder, be like, where's that 858 00:42:53,040 --> 00:42:56,279 Speaker 1: energy going. Energy doesn't go anywhere when a photon gets 859 00:42:56,320 --> 00:42:59,120 Speaker 1: red shifted. It's because the relative velocity between you and 860 00:42:59,160 --> 00:43:01,680 Speaker 1: the source. So it really just sort of like depends 861 00:43:01,760 --> 00:43:04,960 Speaker 1: on the frame of reference, doesn't really go anywhere. Well, 862 00:43:04,960 --> 00:43:07,280 Speaker 1: maybe we should talk a little bit first then about 863 00:43:07,320 --> 00:43:09,719 Speaker 1: what it means to wred shift something and what are 864 00:43:09,719 --> 00:43:12,000 Speaker 1: the different ways that can happen, because I think it 865 00:43:12,040 --> 00:43:14,320 Speaker 1: can happen in two ways. Right, whether the source of 866 00:43:14,440 --> 00:43:17,279 Speaker 1: light is moving away from you, or you're moving away 867 00:43:17,280 --> 00:43:19,479 Speaker 1: from the source of light, then the photon is gonna 868 00:43:19,600 --> 00:43:22,200 Speaker 1: look redder. It can also happen because of the stretching 869 00:43:22,239 --> 00:43:24,719 Speaker 1: of space, right, Yeah, there are two different ways to 870 00:43:24,840 --> 00:43:27,919 Speaker 1: red shift of photon. If an object that shoots light 871 00:43:28,000 --> 00:43:30,720 Speaker 1: at you is moving away from you really really fast, 872 00:43:30,840 --> 00:43:33,799 Speaker 1: then the wavelength of that light is stretched out and 873 00:43:33,840 --> 00:43:36,480 Speaker 1: so it gets redder. Remember the light always travels at 874 00:43:36,520 --> 00:43:39,080 Speaker 1: the same speed, So if somebody's in a galaxy far 875 00:43:39,120 --> 00:43:41,400 Speaker 1: far away and they're moving away from you really quickly 876 00:43:41,680 --> 00:43:44,759 Speaker 1: and they shoot a blue laser at you, then it's 877 00:43:44,760 --> 00:43:46,239 Speaker 1: still going to arrive here at the speed of light. 878 00:43:46,239 --> 00:43:48,200 Speaker 1: It always travels at the speed of light, but it 879 00:43:48,320 --> 00:43:51,440 Speaker 1: changes the wavelength, so it gets red shifted. This is 880 00:43:51,440 --> 00:43:54,120 Speaker 1: a handy way to measure the velocity of things that 881 00:43:54,160 --> 00:43:56,440 Speaker 1: are far away that we can't otherwise measure. If we 882 00:43:56,480 --> 00:43:58,760 Speaker 1: can measure their red shift, then we know how fast 883 00:43:58,800 --> 00:44:01,319 Speaker 1: they are going relative to us. But you're right, there's 884 00:44:01,360 --> 00:44:04,680 Speaker 1: a second way that photons can get stretched out, and 885 00:44:04,680 --> 00:44:08,560 Speaker 1: that's if space itself is expanding, So not just things 886 00:44:08,640 --> 00:44:12,080 Speaker 1: moving through space, but space itself making more of itself, 887 00:44:12,120 --> 00:44:15,279 Speaker 1: bubbling up from within to stretch itself out. And we 888 00:44:15,320 --> 00:44:18,320 Speaker 1: think that's happening in the universe. The whole universe is expanding, 889 00:44:18,360 --> 00:44:21,520 Speaker 1: and that expansion is accelerating, and so photons moving through 890 00:44:21,520 --> 00:44:24,600 Speaker 1: the universe gets stretched out. A great example is the 891 00:44:24,640 --> 00:44:28,800 Speaker 1: cosmic microwave background radiation. We measure these at very very 892 00:44:28,840 --> 00:44:33,319 Speaker 1: long wavelengths, very very red light. But originally when it 893 00:44:33,360 --> 00:44:36,239 Speaker 1: was generated, it was generated by a very hot plasma 894 00:44:36,400 --> 00:44:40,239 Speaker 1: thousands and thousands of degrees, so it was very short wavelength. 895 00:44:40,520 --> 00:44:43,040 Speaker 1: But over the timeline of the universe, those photons have 896 00:44:43,080 --> 00:44:47,160 Speaker 1: gotten stretched out to very very long wavelengths. It's interesting 897 00:44:47,200 --> 00:44:50,080 Speaker 1: to think that the color of a photon depends on 898 00:44:50,160 --> 00:44:53,000 Speaker 1: your perspective in a way, right, Like I can make 899 00:44:53,040 --> 00:44:55,120 Speaker 1: a photon here and I put a lot of energy 900 00:44:55,200 --> 00:44:57,480 Speaker 1: into it, so it's really blue. But depending on how 901 00:44:57,560 --> 00:45:00,439 Speaker 1: you catch it, you're gonna think or that the in color. 902 00:45:01,040 --> 00:45:03,440 Speaker 1: I might think, oh, this is super low energy if 903 00:45:03,440 --> 00:45:06,160 Speaker 1: you catch it while on the run. It feels weird 904 00:45:06,200 --> 00:45:08,879 Speaker 1: because energy feels like a fundamental thing, and people say 905 00:45:08,920 --> 00:45:11,040 Speaker 1: it's conserved, and so it feels weird to think like 906 00:45:11,320 --> 00:45:14,520 Speaker 1: different people could measure different energy. There's an important difference 907 00:45:14,560 --> 00:45:19,600 Speaker 1: between something being conserved and something being invariant. Something invariant 908 00:45:19,640 --> 00:45:23,040 Speaker 1: means that everybody measures the same thing. Everybody always measures 909 00:45:23,040 --> 00:45:24,520 Speaker 1: the speed of light to be the same, but you 910 00:45:24,560 --> 00:45:26,920 Speaker 1: don't always measure energy to be the same. So you're 911 00:45:26,960 --> 00:45:29,080 Speaker 1: running past me and I throw a ball. I see 912 00:45:29,120 --> 00:45:31,400 Speaker 1: the ball moving really really fast, has a lot of energy. 913 00:45:31,600 --> 00:45:33,560 Speaker 1: I say, but if the ball is moving at the 914 00:45:33,600 --> 00:45:36,560 Speaker 1: same speed you are, then it has no velocity relative 915 00:45:36,600 --> 00:45:38,319 Speaker 1: to you, and you say, no, the ball is at rest, 916 00:45:38,360 --> 00:45:40,960 Speaker 1: it has no energy. So you don't even need relativity 917 00:45:41,280 --> 00:45:44,680 Speaker 1: to disagree about the energy to things have. Yeah, that's 918 00:45:44,719 --> 00:45:46,719 Speaker 1: super trippy, but I think what you're saying is that 919 00:45:46,800 --> 00:45:48,560 Speaker 1: you know, if you just catch a photon out in 920 00:45:48,640 --> 00:45:50,640 Speaker 1: space and you see that it's red, there's no way 921 00:45:50,680 --> 00:45:53,000 Speaker 1: for you to know just looking at the photon whether 922 00:45:53,040 --> 00:45:55,200 Speaker 1: it started out as red, or if it started out 923 00:45:55,200 --> 00:45:57,239 Speaker 1: as blue, or if it was blue and a turn red. 924 00:45:57,280 --> 00:45:58,840 Speaker 1: There's like no way for you to know if you 925 00:45:58,880 --> 00:46:01,080 Speaker 1: don't know anything about word it came from. That's right. 926 00:46:01,120 --> 00:46:03,239 Speaker 1: So you get a photon from another galaxy, it's got 927 00:46:03,239 --> 00:46:05,960 Speaker 1: a specific frequency. You don't know what frequency you would 928 00:46:06,000 --> 00:46:07,840 Speaker 1: see it at if you were in the rest frame 929 00:46:07,920 --> 00:46:10,279 Speaker 1: of the galaxy. You just can't tell, right. But if 930 00:46:10,320 --> 00:46:12,320 Speaker 1: you know something about where it came from, or do 931 00:46:12,320 --> 00:46:14,200 Speaker 1: you have more of them coming from the same source, 932 00:46:14,239 --> 00:46:16,839 Speaker 1: you could maybe the dues whether they were made at 933 00:46:16,840 --> 00:46:19,200 Speaker 1: a certain frequency or not exactly. Because this is something 934 00:46:19,200 --> 00:46:20,680 Speaker 1: we do all the time. We look at a whole 935 00:46:20,719 --> 00:46:22,800 Speaker 1: galaxy and we say, oh, the life from here is 936 00:46:22,840 --> 00:46:24,920 Speaker 1: red shifted. So if we can't tell from an into 937 00:46:25,160 --> 00:46:27,960 Speaker 1: individual photon, how can you tell the red shift of 938 00:46:27,960 --> 00:46:30,359 Speaker 1: a galaxy. The answer is, as you say, you look 939 00:46:30,400 --> 00:46:32,760 Speaker 1: at all of them at once, because the galaxy emits 940 00:46:32,800 --> 00:46:36,960 Speaker 1: photons at certain frequencies. It's filled with specific gases hydrogen 941 00:46:37,000 --> 00:46:40,200 Speaker 1: and helium and neon, whatever, And each of those gases 942 00:46:40,200 --> 00:46:44,719 Speaker 1: admit only at certain frequencies because remember they're all quantum objects, 943 00:46:44,960 --> 00:46:47,480 Speaker 1: and they have electrons whizzing around them, and those electrons 944 00:46:47,520 --> 00:46:50,319 Speaker 1: like to go up or down energy levels, and those 945 00:46:50,400 --> 00:46:52,760 Speaker 1: energy levels are sort of like floors in a building. 946 00:46:53,000 --> 00:46:56,080 Speaker 1: The elevator stops at one, or at five or at seven. 947 00:46:56,120 --> 00:46:58,800 Speaker 1: It doesn't stop at like floor four point seven two, 948 00:46:58,880 --> 00:47:02,480 Speaker 1: And so the electrons give off photons of very specific energies. 949 00:47:02,520 --> 00:47:04,399 Speaker 1: If you have a bunch of hydrogen gas and it's 950 00:47:04,440 --> 00:47:07,480 Speaker 1: hot and glowing, it's gonna glow its specific frequencies. So 951 00:47:07,520 --> 00:47:09,719 Speaker 1: if you look at the energy of the photons you're 952 00:47:09,719 --> 00:47:12,000 Speaker 1: getting from a big blob of gas, you can tell 953 00:47:12,160 --> 00:47:14,800 Speaker 1: is it hydrogen, is it helium, is it neon? Based 954 00:47:14,840 --> 00:47:17,480 Speaker 1: on the energies of those photons. But if it was 955 00:47:17,520 --> 00:47:20,560 Speaker 1: just missing one frequency, right like if the source only 956 00:47:20,560 --> 00:47:23,440 Speaker 1: had one element in it, then would it would be 957 00:47:23,520 --> 00:47:25,319 Speaker 1: hard to tell. It's only when you have you know, 958 00:47:25,400 --> 00:47:28,880 Speaker 1: complex things like stars that you know have multiple elements 959 00:47:28,920 --> 00:47:31,759 Speaker 1: in it, that you can sort of identified the light. Right, 960 00:47:31,880 --> 00:47:34,120 Speaker 1: You can actually do it with just hydrogen because hydrogen 961 00:47:34,200 --> 00:47:37,360 Speaker 1: has multiple levels. It has a whole set of energy levels. 962 00:47:37,360 --> 00:47:40,640 Speaker 1: So hydrogen gas emits not just one frequency but many 963 00:47:40,719 --> 00:47:42,280 Speaker 1: to What you do is you look at the spectrum 964 00:47:42,280 --> 00:47:44,000 Speaker 1: you see and you compare it to what you expect. 965 00:47:44,080 --> 00:47:46,120 Speaker 1: You say, oh, this looks like hydrogen, but it's been 966 00:47:46,120 --> 00:47:49,440 Speaker 1: shifted over a little bit. So hydrogen has its own fingerprint, 967 00:47:49,719 --> 00:47:53,200 Speaker 1: helium has its own fingerprint, Neon has its own fingerprint. 968 00:47:53,480 --> 00:47:55,720 Speaker 1: So you can actually tell all of these things apart, 969 00:47:56,000 --> 00:47:58,080 Speaker 1: and you cannot only measure the red shift. You can 970 00:47:58,200 --> 00:48:01,279 Speaker 1: also measure the elemental company positions. You can tell how 971 00:48:01,400 --> 00:48:03,799 Speaker 1: much helium there is, and how much hydrogen there is, 972 00:48:03,800 --> 00:48:06,239 Speaker 1: and how much water vapor there is by where those 973 00:48:06,280 --> 00:48:08,759 Speaker 1: peaks are. You don't you wouldn't get confused between like 974 00:48:08,880 --> 00:48:11,759 Speaker 1: hydrogen and helium because the two are different. Yeah, the 975 00:48:11,760 --> 00:48:14,000 Speaker 1: two aren't different even if they're shifted, because they're all 976 00:48:14,000 --> 00:48:16,799 Speaker 1: shifted together typically, Right, the hydrogen and helium, and that 977 00:48:16,840 --> 00:48:20,360 Speaker 1: galaxy are all moving at the same speed relative to you. Mostly. 978 00:48:20,520 --> 00:48:24,040 Speaker 1: It's actually also the way we measure the rotations of galaxies. 979 00:48:24,160 --> 00:48:25,880 Speaker 1: We look at like one side of the galaxy, but 980 00:48:26,160 --> 00:48:28,560 Speaker 1: the other we see different shifts, which tells us that 981 00:48:28,600 --> 00:48:31,239 Speaker 1: the galaxy is rotating in a certain way because parts 982 00:48:31,239 --> 00:48:32,960 Speaker 1: of it are moving towards us and parts of it 983 00:48:33,000 --> 00:48:35,120 Speaker 1: are moving away from us. Right. But I guess I 984 00:48:35,160 --> 00:48:37,360 Speaker 1: mean if we had a whole galaxy of just hydrogen 985 00:48:37,440 --> 00:48:39,920 Speaker 1: and another whole galaxy of just helium, would you be 986 00:48:40,000 --> 00:48:42,560 Speaker 1: able to tell the two apart or would you be confused? 987 00:48:42,560 --> 00:48:45,440 Speaker 1: It's like, oh, maybe this is hydrogen but shifted to helium, 988 00:48:45,520 --> 00:48:47,920 Speaker 1: or maybe this is helium shifted to hydrogen. Well, our 989 00:48:47,960 --> 00:48:50,240 Speaker 1: voices would all sound really weird if the whole universe 990 00:48:50,280 --> 00:48:52,400 Speaker 1: was just helium. Right, So that's clue number one, but 991 00:48:52,520 --> 00:48:56,080 Speaker 1: also clue number two. Scientifically, they do have a different spectrum, right, 992 00:48:56,120 --> 00:48:58,720 Speaker 1: Helium and hydrogen have different spectrum that have different energy 993 00:48:58,800 --> 00:49:01,520 Speaker 1: levels because it's a different charge in the nucleus, So 994 00:49:01,560 --> 00:49:04,319 Speaker 1: the solutions to the Shorteninger equation aren't different. So the 995 00:49:04,360 --> 00:49:07,319 Speaker 1: gaps between the energy levels and helium are different than 996 00:49:07,320 --> 00:49:10,200 Speaker 1: in hydrogen. So there's no way to take helium and 997 00:49:10,280 --> 00:49:12,920 Speaker 1: like red shifted to make it look like hydrogen. All right, 998 00:49:12,960 --> 00:49:15,640 Speaker 1: So then you wouldn't need to know where it came from, 999 00:49:15,760 --> 00:49:17,359 Speaker 1: or would you. I mean, once you get the light 1000 00:49:17,440 --> 00:49:19,520 Speaker 1: and you see these fingerprints and you instantly know whether 1001 00:49:19,520 --> 00:49:21,600 Speaker 1: it was red shifted or not, yeah, exactly, because there's 1002 00:49:21,600 --> 00:49:23,680 Speaker 1: no other way to make those fingerprints. There's no gas 1003 00:49:23,680 --> 00:49:27,880 Speaker 1: in the universe that emits light like hydrogen red shifted 1004 00:49:27,880 --> 00:49:30,200 Speaker 1: with the Z of four, right, So once you see 1005 00:49:30,200 --> 00:49:32,840 Speaker 1: that spectrum like, well, this has to be hydrogen, and 1006 00:49:32,880 --> 00:49:35,000 Speaker 1: it has to be red shifted this certain amount. There's 1007 00:49:35,040 --> 00:49:38,000 Speaker 1: no other way to make this pattern of light. Right. 1008 00:49:38,040 --> 00:49:40,000 Speaker 1: But to see I guess, to see those fingerprints, you 1009 00:49:40,040 --> 00:49:43,239 Speaker 1: need a whole bunch of photons of different frequencies, right, 1010 00:49:43,239 --> 00:49:46,879 Speaker 1: You need your source to emit a whole range of frequencies. 1011 00:49:46,920 --> 00:49:49,240 Speaker 1: Whereas if you just got a whole bunch of photons 1012 00:49:49,239 --> 00:49:51,239 Speaker 1: in one frequency, there's no way you could tell they 1013 00:49:51,239 --> 00:49:52,759 Speaker 1: were red shifted. Or even if you've got like a 1014 00:49:52,800 --> 00:49:55,640 Speaker 1: weird sampling of different photons of different frequencies, there's no 1015 00:49:55,680 --> 00:49:57,360 Speaker 1: way for you to know. You you would have to 1016 00:49:57,400 --> 00:50:01,200 Speaker 1: assume it came from you know, stars or a galaxy. Yes, 1017 00:50:01,280 --> 00:50:03,720 Speaker 1: not information you can get from one photon. It doesn't 1018 00:50:03,760 --> 00:50:06,279 Speaker 1: carry its own personal history around. It's only from a 1019 00:50:06,280 --> 00:50:09,440 Speaker 1: whole collection of photons that you can tell what the 1020 00:50:09,520 --> 00:50:12,080 Speaker 1: red shift was of the source. But so if like 1021 00:50:12,120 --> 00:50:14,560 Speaker 1: an alien and another galaxy shot a laser ad you 1022 00:50:14,719 --> 00:50:17,480 Speaker 1: that they manufactured artificially, there would be no way for 1023 00:50:17,520 --> 00:50:20,200 Speaker 1: you to tell whether it was red shifted, right, Yeah, exactly, 1024 00:50:20,480 --> 00:50:23,280 Speaker 1: we wouldn't be able to tell what the original frequency 1025 00:50:23,440 --> 00:50:25,840 Speaker 1: was and what the shift of the frequency was, assuming 1026 00:50:25,920 --> 00:50:28,319 Speaker 1: that they could make a laser of arbitrary frequency, right, 1027 00:50:28,360 --> 00:50:32,040 Speaker 1: which they're aliens who probably Yes, right, you're given the 1028 00:50:32,080 --> 00:50:34,080 Speaker 1: aliens a lot of credit here. I mean, I'm assuming 1029 00:50:34,080 --> 00:50:36,359 Speaker 1: they're still bound by the laws of physics, right right, 1030 00:50:36,480 --> 00:50:38,440 Speaker 1: You're assuming they're in the right time zone to shoot 1031 00:50:38,480 --> 00:50:40,719 Speaker 1: you the laser in then they know what they're doing. 1032 00:50:40,760 --> 00:50:42,520 Speaker 1: Maybe that's going to save us, right, Maybe they want 1033 00:50:42,520 --> 00:50:44,720 Speaker 1: to vaporize us, but they used the wrong time zone, 1034 00:50:44,840 --> 00:50:48,040 Speaker 1: and so they actually vaporized Geneva instead of us. Yeah, 1035 00:50:48,200 --> 00:50:49,879 Speaker 1: they get rid of the Danish. What are we gonna 1036 00:50:49,880 --> 00:50:53,919 Speaker 1: have for breakfast without the Danish? Yeah? And then we'd 1037 00:50:53,960 --> 00:50:57,600 Speaker 1: all be drinking ammonia, and you know, in Denmark, of course, 1038 00:50:57,680 --> 00:50:59,759 Speaker 1: they don't call Danish. Is Danish is? They just call 1039 00:50:59,840 --> 00:51:04,879 Speaker 1: it breakfast. They call him Vienna bread. Actually Vienna bread? Wow? 1040 00:51:04,920 --> 00:51:07,879 Speaker 1: What do they call him Vienna? I don't know. I've 1041 00:51:07,920 --> 00:51:10,960 Speaker 1: never been to Vienna. I got the time zone wrong. 1042 00:51:11,000 --> 00:51:12,800 Speaker 1: I was supposed to go, but I missed by flight. 1043 00:51:13,000 --> 00:51:15,920 Speaker 1: Somebody from Vienna right in and please educate us. That's right? 1044 00:51:16,120 --> 00:51:19,319 Speaker 1: And is the Danish is the pastry red shifted or not? 1045 00:51:19,760 --> 00:51:22,160 Speaker 1: If you eat it in Denmark or Vienna? I don't know. 1046 00:51:22,239 --> 00:51:26,720 Speaker 1: Is it blueberry shifted or is it raspberry shifted? Deep questions? 1047 00:51:26,800 --> 00:51:28,880 Speaker 1: All right, Well, I think that answer is Josh's question 1048 00:51:29,000 --> 00:51:31,560 Speaker 1: is that you you can't tell the difference if you 1049 00:51:31,640 --> 00:51:34,000 Speaker 1: just look at a photon if it's red shifted or not. 1050 00:51:34,239 --> 00:51:36,000 Speaker 1: But if you get a whole bunch of photons and 1051 00:51:36,040 --> 00:51:38,759 Speaker 1: you assume they come from you know, natural sources, then 1052 00:51:38,800 --> 00:51:41,360 Speaker 1: you could the dudes whether it was red shifted or 1053 00:51:41,360 --> 00:51:43,719 Speaker 1: not exactly. And it's a great question because it's really 1054 00:51:43,719 --> 00:51:45,879 Speaker 1: good to think about, like how do we actually know 1055 00:51:46,040 --> 00:51:48,239 Speaker 1: what we know? And are we sure we're not being 1056 00:51:48,239 --> 00:51:51,160 Speaker 1: confused about what we're looking at? Basically, the light has 1057 00:51:51,200 --> 00:51:55,239 Speaker 1: to be organic, otherwise you can't tell it has me 1058 00:51:55,320 --> 00:51:59,600 Speaker 1: natural at least farm raised. You know, cage free light 1059 00:52:00,000 --> 00:52:02,319 Speaker 1: and you can tell that's right. No pesticides please in 1060 00:52:02,360 --> 00:52:04,560 Speaker 1: our astronomy. All right, well, I think that answers all 1061 00:52:04,560 --> 00:52:07,399 Speaker 1: of our questions here today. Thank you everyone who sent 1062 00:52:07,480 --> 00:52:09,920 Speaker 1: in their questions. We love getting questions, we really do. 1063 00:52:10,040 --> 00:52:12,400 Speaker 1: It's not just something we say. Please do right to 1064 00:52:12,480 --> 00:52:14,960 Speaker 1: us two questions at Daniel and Jorge dot com. We 1065 00:52:15,040 --> 00:52:17,799 Speaker 1: love hearing from you. You might even pick the question 1066 00:52:17,880 --> 00:52:19,799 Speaker 1: to answer on the podcast, even if you are a 1067 00:52:19,800 --> 00:52:21,879 Speaker 1: Twins fan. I don't even know where the twins are from. 1068 00:52:21,880 --> 00:52:26,160 Speaker 1: Are they from the Twin Cities, Minnesota? Man? What is 1069 00:52:26,200 --> 00:52:29,800 Speaker 1: it hockey or basketball? I think it's lacrosse lacrosse. It 1070 00:52:29,840 --> 00:52:32,279 Speaker 1: looks like lacrosse, depending on your point of view. All right, well, 1071 00:52:32,320 --> 00:52:34,680 Speaker 1: we hope you enjoyed that. Thanks for joining us, See 1072 00:52:34,680 --> 00:52:45,000 Speaker 1: you next time. Thanks for listening, and remember that. Daniel 1073 00:52:45,040 --> 00:52:47,560 Speaker 1: and Jorge Explain the Universe is a production of I 1074 00:52:47,800 --> 00:52:51,239 Speaker 1: Heart Radio. For more podcast from my Heart Radio, visit 1075 00:52:51,239 --> 00:52:54,759 Speaker 1: the I Heart Radio app, Apple Podcasts, or wherever you 1076 00:52:54,880 --> 00:53:01,920 Speaker 1: listen to your favorite shows. No