1 00:00:08,480 --> 00:00:11,360 Speaker 1: Hey, Jorge, do you still have that pet black hole 2 00:00:11,440 --> 00:00:14,760 Speaker 1: in your backyard? Well, you know, my physics lawyer tells 3 00:00:14,800 --> 00:00:19,239 Speaker 1: me as you'd neither confirm nor deny that that's good advice. 4 00:00:19,480 --> 00:00:22,160 Speaker 1: So in that case, I have a question for your 5 00:00:22,200 --> 00:00:26,720 Speaker 1: physics lawyer. He charges a lot better be good. All right, 6 00:00:26,880 --> 00:00:30,000 Speaker 1: is my question. How do you actually know that it's 7 00:00:30,040 --> 00:00:32,440 Speaker 1: a black hole? Well, it's either a black hole or 8 00:00:32,520 --> 00:00:35,519 Speaker 1: something else that eats a lot of bananas. All right, 9 00:00:35,600 --> 00:00:37,920 Speaker 1: So you either have a black hole or King Kong 10 00:00:38,080 --> 00:00:41,480 Speaker 1: living in your backyard. Either way, I definitely need more bananas. 11 00:00:56,760 --> 00:01:00,240 Speaker 1: I am or handmade cartoonist and the creator of PhD comic. Hi. 12 00:01:00,320 --> 00:01:03,520 Speaker 1: I'm Daniel. I'm a particle physicist, and I think the 13 00:01:03,640 --> 00:01:06,480 Speaker 1: universe is kind of bananas. Welcome to our podcast. Daniel 14 00:01:06,520 --> 00:01:09,760 Speaker 1: and Jorge explained the university production of I Heart Radio, 15 00:01:09,840 --> 00:01:11,960 Speaker 1: in which we take you on a tour of everything 16 00:01:12,000 --> 00:01:15,680 Speaker 1: that's crazy and amazing about our universe, which turns out 17 00:01:15,720 --> 00:01:17,640 Speaker 1: to be most of it. We talk to you about 18 00:01:17,640 --> 00:01:19,479 Speaker 1: the things that we do know and about the things 19 00:01:19,480 --> 00:01:21,920 Speaker 1: that we don't know, the things that scientists are trying 20 00:01:21,920 --> 00:01:24,960 Speaker 1: to figure out, and the things that you are wondering about. 21 00:01:25,000 --> 00:01:28,440 Speaker 1: This incredible, glittering cosmos we find ourselves in. Yeah, all 22 00:01:28,520 --> 00:01:32,560 Speaker 1: the amazing stuff out there that's mysterious and interesting and 23 00:01:32,640 --> 00:01:36,760 Speaker 1: intriguing and potentially mind blowing. And sometimes we also like 24 00:01:36,800 --> 00:01:39,640 Speaker 1: to talk about how we discover things, because you know, 25 00:01:39,720 --> 00:01:42,119 Speaker 1: I think that how we discover things sometimes it's almost 26 00:01:42,160 --> 00:01:44,800 Speaker 1: as important as knowing the thing itself, because that's how 27 00:01:44,840 --> 00:01:47,440 Speaker 1: we know it's there and tells us a little bit 28 00:01:47,480 --> 00:01:50,880 Speaker 1: about how science works. Yeah, as an experimentalist, I always 29 00:01:50,920 --> 00:01:53,320 Speaker 1: want to know, like, how do we know that's true? 30 00:01:53,400 --> 00:01:56,280 Speaker 1: You're telling me this thing exists in the universe. How 31 00:01:56,280 --> 00:01:59,279 Speaker 1: do we really know? What is the evidence that convinced people? 32 00:01:59,600 --> 00:02:01,560 Speaker 1: Because there was a moment in science when we didn't 33 00:02:01,560 --> 00:02:03,680 Speaker 1: think it existed, and then all of a sudden things 34 00:02:03,680 --> 00:02:06,600 Speaker 1: shifted and everybody was convinced. What were the pieces of 35 00:02:06,640 --> 00:02:09,600 Speaker 1: evidence that came together in people's minds that made them 36 00:02:09,600 --> 00:02:14,240 Speaker 1: believe something new and wacky and unbelievable was real. Daniel, 37 00:02:14,280 --> 00:02:16,560 Speaker 1: is there the equivalent of like a behind the scenes 38 00:02:17,080 --> 00:02:19,960 Speaker 1: clip for physics? You know, like when you publish a paper, 39 00:02:20,000 --> 00:02:23,760 Speaker 1: do you also publish the commentary or behind the scenes 40 00:02:23,919 --> 00:02:29,800 Speaker 1: or bloopers? You know, sometimes people accidentally leave little comments 41 00:02:29,840 --> 00:02:32,000 Speaker 1: in their paper. I mean they're not visible in the 42 00:02:32,040 --> 00:02:34,600 Speaker 1: final product, but they're sort of hidden inside the text 43 00:02:34,639 --> 00:02:37,120 Speaker 1: that creates the paper, and you can scan through and 44 00:02:37,160 --> 00:02:40,440 Speaker 1: you can see people authors arguing about what they should 45 00:02:40,480 --> 00:02:43,240 Speaker 1: put in the paper, like this next line is hot garbage, 46 00:02:43,240 --> 00:02:47,040 Speaker 1: we should cut it out. Stuff like that. Yeah, no kidding. 47 00:02:47,160 --> 00:02:49,760 Speaker 1: It's the equivalent of like leaving little comments in your 48 00:02:49,760 --> 00:02:53,040 Speaker 1: Microsoft word document. We usually write our stuff in l tech, 49 00:02:53,080 --> 00:02:55,880 Speaker 1: and you can put comments inside the source and sometimes 50 00:02:55,919 --> 00:02:58,600 Speaker 1: people forget to pull that stuff out, and so you 51 00:02:58,639 --> 00:03:01,360 Speaker 1: can get some pretty hilarious insights into how the paper 52 00:03:01,480 --> 00:03:04,800 Speaker 1: was Does anyone ever say we totally made this up? 53 00:03:04,800 --> 00:03:08,040 Speaker 1: But don't tell anybody no? And it's not usually a 54 00:03:08,160 --> 00:03:10,600 Speaker 1: dramatic It's not like you know, the Last Dance that 55 00:03:11,040 --> 00:03:14,280 Speaker 1: documentary about Michael Jordan's We don't have you know, that 56 00:03:14,400 --> 00:03:17,280 Speaker 1: much drama in physics. Usually if you're writing papers with people, 57 00:03:17,440 --> 00:03:20,440 Speaker 1: then you mostly agree. Most of the drama is between papers, 58 00:03:20,520 --> 00:03:23,440 Speaker 1: like you know, this paper says the other paper was wrong, 59 00:03:23,520 --> 00:03:25,440 Speaker 1: and those folks over there in that university don't know 60 00:03:25,480 --> 00:03:28,160 Speaker 1: what they're talking about. That's where most of the conflict 61 00:03:28,200 --> 00:03:31,680 Speaker 1: with you. That's right, Hey, the stakes are high. You know, 62 00:03:31,720 --> 00:03:33,560 Speaker 1: we are trying to figure out the nature of the 63 00:03:33,680 --> 00:03:37,280 Speaker 1: universe itself. Here, man, it's not just basketball. You can't 64 00:03:37,280 --> 00:03:40,120 Speaker 1: get catty enough when it comes to the universe. So 65 00:03:40,280 --> 00:03:41,720 Speaker 1: to be on the program, we'll be talking about the 66 00:03:41,760 --> 00:03:44,240 Speaker 1: discovery of something that I guess most people have heard 67 00:03:44,280 --> 00:03:48,040 Speaker 1: of this. You know, everyone who's interested in science and 68 00:03:48,120 --> 00:03:50,920 Speaker 1: space probably has heard of these, but I've been not 69 00:03:50,960 --> 00:03:53,560 Speaker 1: a lot of people know how they were discovered. That's right. 70 00:03:53,600 --> 00:03:56,560 Speaker 1: It's something that's extra weird and fascinating in the universe, 71 00:03:56,600 --> 00:03:59,000 Speaker 1: and it took science a long time to come to 72 00:03:59,040 --> 00:04:02,000 Speaker 1: grips with the idea that they could actually be out there, 73 00:04:02,040 --> 00:04:05,080 Speaker 1: that they could really be a real weird thing in 74 00:04:05,160 --> 00:04:07,800 Speaker 1: our universe. And this is something that happens a lot 75 00:04:08,000 --> 00:04:10,160 Speaker 1: sort of in physics, that we have an idea for 76 00:04:10,240 --> 00:04:12,760 Speaker 1: something weird and strange, we think, well, that's just like 77 00:04:12,800 --> 00:04:16,200 Speaker 1: some mathematical artifact that's not actually real, it doesn't really 78 00:04:16,320 --> 00:04:19,640 Speaker 1: happen out there, and then we discover, wow, the universe 79 00:04:19,720 --> 00:04:24,320 Speaker 1: actually is that weird. Quantum mechanics is real, Electrons really 80 00:04:24,360 --> 00:04:27,919 Speaker 1: are determined by weird probabilities. And so we're sort of 81 00:04:27,960 --> 00:04:30,520 Speaker 1: coming to grips with we're waking up to realize that 82 00:04:30,560 --> 00:04:33,560 Speaker 1: the universe is stranger than we ever imagined. Yeah, and 83 00:04:33,600 --> 00:04:37,040 Speaker 1: this thing is extra strange and extra weird. It's one 84 00:04:37,040 --> 00:04:40,279 Speaker 1: of the maybe a true like pockets of mystery in 85 00:04:40,320 --> 00:04:43,800 Speaker 1: the universe that we may never even discover what's inside 86 00:04:43,800 --> 00:04:45,800 Speaker 1: of him. So to be on the podcast, we'll be 87 00:04:45,880 --> 00:04:54,799 Speaker 1: asking the question how do we discover black holes? So, Daniel, 88 00:04:54,839 --> 00:04:56,800 Speaker 1: I assume we didn't just fall into one by accident. 89 00:04:57,040 --> 00:04:59,800 Speaker 1: We're inside one right now. Welcome to the podcast Why 90 00:05:00,040 --> 00:05:05,520 Speaker 1: inside the black Hole that notity will ever hear? We 91 00:05:05,560 --> 00:05:08,200 Speaker 1: are literally screaming into the void. There's an idea that 92 00:05:08,240 --> 00:05:11,360 Speaker 1: maybe we are inside of a black hole. Isn't that possibility? Yeah, 93 00:05:11,400 --> 00:05:15,440 Speaker 1: that's a possibility. It's theoretically possible that our entire universe 94 00:05:15,640 --> 00:05:19,480 Speaker 1: is inside another black hole. We had the Loop quantum 95 00:05:19,560 --> 00:05:21,919 Speaker 1: gravity theorist come on. We asked her what's inside a 96 00:05:21,920 --> 00:05:25,400 Speaker 1: black hole? And she actually said maybe an entire universe, 97 00:05:25,720 --> 00:05:27,880 Speaker 1: And so that's fun to think about. But you know 98 00:05:27,880 --> 00:05:30,920 Speaker 1: the problem with black holes is that we can't see 99 00:05:30,960 --> 00:05:33,359 Speaker 1: inside them, so we don't know what's inside them. And 100 00:05:33,360 --> 00:05:36,279 Speaker 1: anybody who does survive the journey into a black hole 101 00:05:36,560 --> 00:05:39,320 Speaker 1: can't then shout to us about what they find. So, 102 00:05:39,560 --> 00:05:42,640 Speaker 1: as you said, they may be eternal pockets of missing. 103 00:05:43,000 --> 00:05:45,040 Speaker 1: So we might be live inside of a black hole 104 00:05:45,200 --> 00:05:49,320 Speaker 1: right now along with everybody else. That's right, along with 105 00:05:49,360 --> 00:05:51,599 Speaker 1: all those socks you've lost that probably went into a 106 00:05:51,600 --> 00:05:54,640 Speaker 1: black hole somewhere. That's an extra black hole, that's like 107 00:05:54,680 --> 00:05:58,480 Speaker 1: a laundry hole. Yeah, it's a big question, like how 108 00:05:58,480 --> 00:06:01,920 Speaker 1: do we know that black holes really exist? What's the evidence? 109 00:06:02,240 --> 00:06:04,560 Speaker 1: And more kind of maybe interesting is how do we 110 00:06:04,600 --> 00:06:06,559 Speaker 1: come to think of them and how do people become 111 00:06:06,600 --> 00:06:09,560 Speaker 1: convinced that they exist even before we had ever seen 112 00:06:09,839 --> 00:06:12,960 Speaker 1: And so, as usual, I pulled our listeners and I 113 00:06:13,000 --> 00:06:15,240 Speaker 1: asked them if they knew about the history of the 114 00:06:15,279 --> 00:06:17,679 Speaker 1: discovery of the black hole, what was the crucial piece 115 00:06:17,720 --> 00:06:20,520 Speaker 1: of evidence that moved it from the category of like 116 00:06:20,720 --> 00:06:25,440 Speaker 1: crazy bonkers theoretical idea to crazy bonkers real actual facts. 117 00:06:25,480 --> 00:06:27,240 Speaker 1: Let's think about it for a second. How do you 118 00:06:27,279 --> 00:06:30,840 Speaker 1: think we discovered black holes? Here's what people had to say. 119 00:06:30,920 --> 00:06:33,880 Speaker 1: There was a star found that was turning red and blue, 120 00:06:33,920 --> 00:06:37,280 Speaker 1: but it didn't but there was no recognizable binary pair 121 00:06:37,680 --> 00:06:40,760 Speaker 1: or another star for it. So that's how they knew 122 00:06:40,839 --> 00:06:43,839 Speaker 1: that it must be a binary pair with a black hole. 123 00:06:44,200 --> 00:06:47,920 Speaker 1: I would say that this is true. Somebody observing the 124 00:06:47,960 --> 00:06:51,240 Speaker 1: space and and has seen some sort of gravitational lensing 125 00:06:51,320 --> 00:06:56,600 Speaker 1: happening that black hole has gone in between a observed 126 00:06:56,640 --> 00:07:01,880 Speaker 1: star and a observer. I believe that they were initially 127 00:07:01,920 --> 00:07:07,200 Speaker 1: discovered by in more of a theoretical sense, by not 128 00:07:07,320 --> 00:07:12,560 Speaker 1: being able to explain the gravity that was missing due 129 00:07:12,600 --> 00:07:15,960 Speaker 1: to the rotation universe and was holding it together. They 130 00:07:16,040 --> 00:07:21,520 Speaker 1: were officially discovered by the gravitational lensing, I believe. I 131 00:07:21,560 --> 00:07:26,160 Speaker 1: think black holes were predicted by Einstein um, but how 132 00:07:26,200 --> 00:07:30,600 Speaker 1: they were discovered was by seeing lensing in stars. An 133 00:07:30,640 --> 00:07:34,240 Speaker 1: idea in which I rather believe is that when two 134 00:07:34,320 --> 00:07:38,960 Speaker 1: black holes, Clyde or black hole is like born, so 135 00:07:39,080 --> 00:07:44,960 Speaker 1: when a star collapse isn't a singularity that these occurrences 136 00:07:45,640 --> 00:07:49,720 Speaker 1: leads like this leads to an emission of race, maybe 137 00:07:49,720 --> 00:07:52,880 Speaker 1: like X rays or gramma rays, I'm not sure. And 138 00:07:53,120 --> 00:07:56,640 Speaker 1: these race were like measured on Earth. I'm not sure, 139 00:07:56,840 --> 00:07:59,320 Speaker 1: but I would guess some gravitational lens effect from what 140 00:07:59,360 --> 00:08:01,880 Speaker 1: I can remember. Instantly, we're the one that figured out 141 00:08:02,080 --> 00:08:05,480 Speaker 1: the black holes were a thing. Was just equations and stuff, 142 00:08:05,520 --> 00:08:08,000 Speaker 1: and then it took years and years and years until 143 00:08:08,480 --> 00:08:11,440 Speaker 1: until I finally found actual evidence of it in real life. 144 00:08:11,480 --> 00:08:14,000 Speaker 1: The only way I contain the black holes were discovered 145 00:08:14,000 --> 00:08:18,040 Speaker 1: were maybe because of their gravitational effect on the surroundings, 146 00:08:18,120 --> 00:08:22,960 Speaker 1: and assume that it was probably a mathematical possibility for 147 00:08:23,080 --> 00:08:27,080 Speaker 1: the existence of such a body which had such strong 148 00:08:27,120 --> 00:08:31,560 Speaker 1: gravitational pull that even light cannot escape, and maybe later 149 00:08:31,600 --> 00:08:35,680 Speaker 1: on they finally found it. All right, pretty interesting answers. Yeah, 150 00:08:35,760 --> 00:08:38,839 Speaker 1: people do have an idea that black holes were first 151 00:08:38,880 --> 00:08:41,880 Speaker 1: thought of and then later discovered, which is pretty cool. 152 00:08:42,320 --> 00:08:45,800 Speaker 1: But the consensus tends to be here some gravitational lensing 153 00:08:45,880 --> 00:08:48,080 Speaker 1: that you could like see a black hole passing in 154 00:08:48,120 --> 00:08:51,040 Speaker 1: front of a star and distorting it, And that's true 155 00:08:51,040 --> 00:08:53,120 Speaker 1: in theory that if that happened, you might be able 156 00:08:53,120 --> 00:08:56,080 Speaker 1: to see it, but that's definitely not how black holes 157 00:08:56,120 --> 00:08:58,840 Speaker 1: were discovered, so not through gravitational lensing. But maybe there's 158 00:08:58,880 --> 00:09:01,840 Speaker 1: some other gravitation means. Yeah, and this actually has a 159 00:09:01,840 --> 00:09:05,360 Speaker 1: lot of parallels to other big mysteries of the universe, 160 00:09:05,440 --> 00:09:07,880 Speaker 1: like dark matter. We've talked about dark matter on this 161 00:09:07,920 --> 00:09:10,320 Speaker 1: podcast a lot. It's something we know is there, but 162 00:09:10,440 --> 00:09:13,679 Speaker 1: only have sort of indirect hints of its existence, and 163 00:09:13,760 --> 00:09:17,680 Speaker 1: all those hints are gravitational. And in a very similar way, 164 00:09:17,760 --> 00:09:21,360 Speaker 1: black holes are very strong, very powerful, very important to 165 00:09:21,400 --> 00:09:25,240 Speaker 1: the universe, but also very hard to see directly because 166 00:09:25,280 --> 00:09:29,400 Speaker 1: they're mostly gravitational objects and gravity is very weak. I 167 00:09:29,400 --> 00:09:31,400 Speaker 1: guess it's hard. How do you see something that's dark 168 00:09:31,520 --> 00:09:35,920 Speaker 1: in space? Especially, it's the perfect camouflage, well done, black holes. 169 00:09:37,480 --> 00:09:40,079 Speaker 1: It's hiding what but what is it hiding from? It's 170 00:09:40,160 --> 00:09:43,800 Speaker 1: hiding from us. I guess, alright, well, step us through here, Daniel, 171 00:09:44,320 --> 00:09:46,920 Speaker 1: Because black holes are sort of interesting in that they 172 00:09:46,960 --> 00:09:50,080 Speaker 1: were thought of theoretically first, or there was sort of 173 00:09:50,080 --> 00:09:53,760 Speaker 1: discovered theoretically first, probably a long time, almost hundred years 174 00:09:53,760 --> 00:09:56,360 Speaker 1: before we actually ever saw one. Yeah, and you might 175 00:09:56,400 --> 00:09:59,920 Speaker 1: be wondering, like, what does it mean to discover something theoretically? Right? 176 00:10:00,120 --> 00:10:01,920 Speaker 1: After all, for things to exist, they have to be 177 00:10:02,040 --> 00:10:05,480 Speaker 1: in our universe, and so experimentally in things that can 178 00:10:05,559 --> 00:10:09,920 Speaker 1: really discover something right, Well, you can actually make discoveries theoretically. 179 00:10:10,280 --> 00:10:12,800 Speaker 1: You can say, here the laws of the universe as 180 00:10:12,840 --> 00:10:15,719 Speaker 1: we think we understand them, what are the consequences of them? 181 00:10:15,720 --> 00:10:18,640 Speaker 1: What are some predictions we can make from these laws 182 00:10:18,720 --> 00:10:21,160 Speaker 1: that would maybe be surprising and so if you like 183 00:10:21,240 --> 00:10:23,040 Speaker 1: look in the corners of the space and say, oh, 184 00:10:23,080 --> 00:10:24,959 Speaker 1: if these laws do this and these laws do that, 185 00:10:25,400 --> 00:10:28,160 Speaker 1: is there something that we hadn't anticipated that these laws 186 00:10:28,240 --> 00:10:31,079 Speaker 1: can do. And that's precisely what happened with black holes. 187 00:10:31,120 --> 00:10:34,160 Speaker 1: We came to some new understanding of the way gravity 188 00:10:34,200 --> 00:10:36,720 Speaker 1: worked and then started to look at the consequences that 189 00:10:36,800 --> 00:10:40,160 Speaker 1: what does that mean? What possible weird stuff can gravity do? 190 00:10:40,559 --> 00:10:44,760 Speaker 1: And people almost literally stumbled over this weird, bizarre prediction 191 00:10:45,080 --> 00:10:47,000 Speaker 1: for what gravity could do. Yeah, I guess you can 192 00:10:47,080 --> 00:10:50,960 Speaker 1: theoretically discover things theoretically. It's kind of what you're saying, yeah, 193 00:10:50,960 --> 00:10:52,960 Speaker 1: And that's exactly what was done, for example, with the 194 00:10:53,000 --> 00:10:56,040 Speaker 1: Higgs boson. The Higgs boson was an idea which first 195 00:10:56,040 --> 00:10:58,640 Speaker 1: came about theoretically. People looked at the pattern of the 196 00:10:58,679 --> 00:11:00,960 Speaker 1: particles and they thought, you know, this would make more 197 00:11:01,040 --> 00:11:03,600 Speaker 1: sense if there was this other thing that existed, and 198 00:11:03,640 --> 00:11:06,680 Speaker 1: then we found it. Very much in contrast to dark matter, 199 00:11:06,760 --> 00:11:09,000 Speaker 1: dark matter is something that was seeing experimental. It was 200 00:11:09,040 --> 00:11:11,839 Speaker 1: like a puzzle in the universe. We didn't understand what 201 00:11:11,880 --> 00:11:14,280 Speaker 1: we were seeing until later we came up with an 202 00:11:14,320 --> 00:11:17,520 Speaker 1: idea to explain it. But black holes were found theoretically, 203 00:11:17,720 --> 00:11:20,240 Speaker 1: and it really, as you said, goes back to the 204 00:11:20,280 --> 00:11:24,400 Speaker 1: genesis of general relativity back in nineteen fifteen when Einstein 205 00:11:24,440 --> 00:11:27,960 Speaker 1: published his final paper on the field equations for general 206 00:11:28,000 --> 00:11:32,480 Speaker 1: relative and then he dropped the mic. He's like, I'm out. 207 00:11:32,679 --> 00:11:35,160 Speaker 1: He sort of did. And the thing to understand about 208 00:11:35,200 --> 00:11:38,040 Speaker 1: his field equations is that they are nasty and complicated, 209 00:11:38,360 --> 00:11:41,760 Speaker 1: like he discovered sort of how space and time talk 210 00:11:41,880 --> 00:11:44,800 Speaker 1: to matter, you know, And what he discovered is that 211 00:11:44,840 --> 00:11:47,560 Speaker 1: space isn't just like an empty backdrop, but it's something 212 00:11:47,559 --> 00:11:51,480 Speaker 1: that's dynamical and that it responds to matter. So matter 213 00:11:51,559 --> 00:11:55,000 Speaker 1: tells space how to curve, how to bend, how to shape, 214 00:11:55,040 --> 00:11:57,319 Speaker 1: and then space tells matter how to move. So it's 215 00:11:57,320 --> 00:12:00,680 Speaker 1: like a complex system, a thing with a lot of feedback, 216 00:12:00,960 --> 00:12:03,000 Speaker 1: and that makes it very difficult to know, like, well, 217 00:12:03,240 --> 00:12:07,120 Speaker 1: what is the solution would actually happened in various circumstances, 218 00:12:07,200 --> 00:12:09,320 Speaker 1: and for a long time, the only thing people could 219 00:12:09,320 --> 00:12:12,000 Speaker 1: ever figure out in terms of the Einstein field equations 220 00:12:12,000 --> 00:12:15,720 Speaker 1: were super simplified universe like the universe field with homogeneous 221 00:12:15,800 --> 00:12:19,720 Speaker 1: dust or totally empty universe like. Nobody's ever solved the 222 00:12:19,720 --> 00:12:22,959 Speaker 1: Einstein field equations for our actual universe. I guess you 223 00:12:23,000 --> 00:12:25,160 Speaker 1: can sort of explore with the equations, right, like if 224 00:12:25,160 --> 00:12:28,040 Speaker 1: you find that the things around you obey as certain 225 00:12:28,160 --> 00:12:30,880 Speaker 1: law or equations like f equals and make and then 226 00:12:31,360 --> 00:12:34,160 Speaker 1: kind of tweaked the numbers and the parameters to kind 227 00:12:34,160 --> 00:12:38,280 Speaker 1: of explore more extreme conditions than what you have around you. Right, 228 00:12:38,600 --> 00:12:40,480 Speaker 1: you could add like what happens if the mask coast 229 00:12:40,480 --> 00:12:43,040 Speaker 1: to zero, or what happens if the force coast to zero, 230 00:12:43,520 --> 00:12:46,320 Speaker 1: and the equations would tell you that's right, and that's 231 00:12:46,320 --> 00:12:50,000 Speaker 1: exactly what happened. So Einstein published these equations in nineteen fifteen, 232 00:12:50,360 --> 00:12:52,480 Speaker 1: and then he sent them to his friend and colleague, 233 00:12:52,720 --> 00:12:56,080 Speaker 1: Short Stild, and short Stile looked at these and he 234 00:12:56,480 --> 00:12:58,679 Speaker 1: played around with him, and he actually found a solution. 235 00:12:58,800 --> 00:13:01,240 Speaker 1: Just a few months later. He found what's one of 236 00:13:01,240 --> 00:13:04,199 Speaker 1: the first exact solutions to the field equations, like a 237 00:13:04,280 --> 00:13:08,600 Speaker 1: configuration of matter and the definition of space that satisfied 238 00:13:08,600 --> 00:13:11,719 Speaker 1: those equations that could be real in the universe. So 239 00:13:11,760 --> 00:13:14,200 Speaker 1: he found this solution, and he found some things about 240 00:13:14,200 --> 00:13:15,760 Speaker 1: it that were kind of weird. Well, I guess to 241 00:13:15,760 --> 00:13:17,560 Speaker 1: step us through a little bit, what did what did 242 00:13:17,559 --> 00:13:19,360 Speaker 1: you mean by a solution to the equations like the 243 00:13:19,360 --> 00:13:25,080 Speaker 1: equations kind of related space and matter, and then you 244 00:13:25,120 --> 00:13:27,120 Speaker 1: have to find a solution for them, and the solutions 245 00:13:27,240 --> 00:13:29,400 Speaker 1: what do the solutions tell you? The solutions tell you 246 00:13:29,480 --> 00:13:32,680 Speaker 1: how space curves. So if you have a configuration of matter, 247 00:13:32,720 --> 00:13:34,600 Speaker 1: if you say I'm going to put a big blob 248 00:13:34,640 --> 00:13:36,680 Speaker 1: of stuff right here in the middle of the universe, 249 00:13:36,920 --> 00:13:39,760 Speaker 1: then the solutions tell you how space curves all the 250 00:13:39,840 --> 00:13:43,200 Speaker 1: way through that universe. And so that's a solution meaning 251 00:13:43,200 --> 00:13:45,719 Speaker 1: how space bends, or like how things move around it. 252 00:13:45,800 --> 00:13:48,440 Speaker 1: How space bends, and then how space bends determines how 253 00:13:48,520 --> 00:13:51,760 Speaker 1: things move right, Like we know that having the Sun 254 00:13:51,840 --> 00:13:54,600 Speaker 1: in the center of our Solar system bends the space 255 00:13:54,679 --> 00:13:57,880 Speaker 1: in its vicinity, so that therefore the Earth moves in 256 00:13:57,960 --> 00:14:00,600 Speaker 1: an orbit around the Sun rather than just lying off 257 00:14:00,640 --> 00:14:03,320 Speaker 1: in what otherwise looks like a straight line. So you 258 00:14:03,360 --> 00:14:05,120 Speaker 1: start with the mass. You said, I'm gonna put this 259 00:14:05,200 --> 00:14:08,680 Speaker 1: mass into the universe. That tells you the shape of space, 260 00:14:09,240 --> 00:14:12,559 Speaker 1: and then that lets you determine the equations of motion 261 00:14:12,600 --> 00:14:15,640 Speaker 1: how something would actually move through that space. So he 262 00:14:15,679 --> 00:14:17,079 Speaker 1: was the first one to figure out if you put 263 00:14:17,080 --> 00:14:20,640 Speaker 1: a really massive object in the universe that's spherically symmetric 264 00:14:20,920 --> 00:14:23,840 Speaker 1: what is the shape of space around it? And what 265 00:14:24,000 --> 00:14:26,600 Speaker 1: he found was really weird. He found that if you 266 00:14:26,640 --> 00:14:30,520 Speaker 1: put in a really heavy mass, enough mass that there's 267 00:14:30,560 --> 00:14:32,760 Speaker 1: this sort of edge to it, that there's this point 268 00:14:32,800 --> 00:14:36,280 Speaker 1: where the curvature space sort of becomes infinite, right, like 269 00:14:36,560 --> 00:14:38,960 Speaker 1: space is curved like it is around the Sun. But 270 00:14:39,000 --> 00:14:42,000 Speaker 1: if the mass gets large enough, then you have this threshold, 271 00:14:42,040 --> 00:14:45,440 Speaker 1: this point which we now call the short styles radius, 272 00:14:45,440 --> 00:14:48,240 Speaker 1: where the curvature of space gets a singularity, or like 273 00:14:48,280 --> 00:14:51,680 Speaker 1: the field equations have this infinity in them. And it's 274 00:14:51,680 --> 00:14:54,000 Speaker 1: not something that he understood at the time the way 275 00:14:54,000 --> 00:14:56,240 Speaker 1: that we understand it now. He didn't say, oh, this 276 00:14:56,320 --> 00:14:58,720 Speaker 1: is the event horizon of a black hole. He was like, 277 00:14:58,960 --> 00:15:01,000 Speaker 1: all right, I found a salut, but it has some 278 00:15:01,120 --> 00:15:03,720 Speaker 1: weirdness at a certain distance from this audition, I see. 279 00:15:03,720 --> 00:15:05,400 Speaker 1: He just sort of like turned the knob on the 280 00:15:05,480 --> 00:15:08,280 Speaker 1: mass and then he found that the equations suddenly kind 281 00:15:08,280 --> 00:15:11,320 Speaker 1: of got wonk. Yeah, they got wonky, And people were like, huh, 282 00:15:11,360 --> 00:15:13,320 Speaker 1: that's weird, and you know that happens a lot in 283 00:15:13,360 --> 00:15:15,920 Speaker 1: theoretical physics. You're like, I found a solution to this 284 00:15:15,960 --> 00:15:18,280 Speaker 1: set of equations. It makes sense over here, I don't 285 00:15:18,280 --> 00:15:20,280 Speaker 1: really understand what's going on in that part, but let's 286 00:15:20,280 --> 00:15:23,520 Speaker 1: just put that aside for now. And people studied it 287 00:15:23,600 --> 00:15:27,080 Speaker 1: for you know, ten years, twenty years, forty years before 288 00:15:27,120 --> 00:15:30,400 Speaker 1: they really had an understanding for what that meant. Initially, 289 00:15:30,680 --> 00:15:33,040 Speaker 1: they only looked at it as well, the curvature of 290 00:15:33,080 --> 00:15:37,200 Speaker 1: space gets really strong here, so time slows down in 291 00:15:37,240 --> 00:15:40,360 Speaker 1: the vicinity of a lot of curvature, and so it 292 00:15:40,440 --> 00:15:43,840 Speaker 1: might be something like a frozen star. They thought, if 293 00:15:44,000 --> 00:15:47,080 Speaker 1: time slows down as you approach this heavy, heavy mass, 294 00:15:47,440 --> 00:15:50,360 Speaker 1: then you'll see time slow down as things approach this thing, 295 00:15:50,640 --> 00:15:53,080 Speaker 1: and it's sort of like time stops when you get 296 00:15:53,080 --> 00:15:55,360 Speaker 1: to that point. So they didn't call it a black 297 00:15:55,360 --> 00:15:58,160 Speaker 1: hole back then. They called it a frozen star. Wow, 298 00:15:58,800 --> 00:16:01,920 Speaker 1: that's almost a little better. Yeah, well, and I think 299 00:16:01,920 --> 00:16:03,640 Speaker 1: that they thought that if you saw one of these 300 00:16:03,680 --> 00:16:07,120 Speaker 1: things in nature, it wouldn't be a black emptiness. It 301 00:16:07,160 --> 00:16:09,720 Speaker 1: would be like a star, but just like frozen in time. 302 00:16:09,800 --> 00:16:12,240 Speaker 1: You know, like if a star grew so massive that 303 00:16:12,280 --> 00:16:15,920 Speaker 1: it passed this threshold, it would just like freeze in whatever, 304 00:16:16,000 --> 00:16:19,040 Speaker 1: like crazy flaming moment it happened to be in, right, 305 00:16:19,080 --> 00:16:21,960 Speaker 1: but it would stop emitting photons in which case it 306 00:16:22,040 --> 00:16:23,880 Speaker 1: might be black. Yeah, well that's not something that they 307 00:16:23,960 --> 00:16:26,520 Speaker 1: understood until much much later, all right, So then it 308 00:16:26,640 --> 00:16:28,800 Speaker 1: was kind of wonkey, And didn't they think that maybe 309 00:16:28,880 --> 00:16:32,120 Speaker 1: the equation was wrong, like like, this is a weird 310 00:16:32,200 --> 00:16:35,800 Speaker 1: result and predict something that seems that would make time stop. 311 00:16:36,120 --> 00:16:40,080 Speaker 1: Maybe our equations are not meant to work in these extremes. Yes, definitely. 312 00:16:40,320 --> 00:16:42,120 Speaker 1: For a long time people thought, well, this is an 313 00:16:42,120 --> 00:16:45,760 Speaker 1: interesting sort of mathematical curiosity, but they thought it couldn't 314 00:16:45,800 --> 00:16:48,760 Speaker 1: be real. They thought instead that it only happened under 315 00:16:48,760 --> 00:16:52,200 Speaker 1: a certain very special, perfectly symmetric conditions that you could 316 00:16:52,240 --> 00:16:54,720 Speaker 1: achieve sort of on the page, but would never actually 317 00:16:54,800 --> 00:16:58,640 Speaker 1: happen in reality. Then in reality something else would interfere, 318 00:16:58,640 --> 00:17:01,200 Speaker 1: would muck it up, so you wouldn't get this weird behavior. 319 00:17:01,640 --> 00:17:03,320 Speaker 1: So for a long time it was like, hey, look 320 00:17:03,360 --> 00:17:06,520 Speaker 1: at this cute, little weird mathematical effect. Of course that's 321 00:17:06,520 --> 00:17:09,719 Speaker 1: not real, like that would never really exist. The universe 322 00:17:09,840 --> 00:17:13,960 Speaker 1: is not that insane. But they had to give it 323 00:17:14,080 --> 00:17:16,720 Speaker 1: some second thoughts later, and then later there were big 324 00:17:16,720 --> 00:17:19,280 Speaker 1: discoveries about him. So let's get into those. But first 325 00:17:19,520 --> 00:17:34,280 Speaker 1: let's take a quick break, all right, Daniel, So what 326 00:17:34,320 --> 00:17:36,200 Speaker 1: do I do about the pet black hole in my backyard? 327 00:17:36,359 --> 00:17:40,119 Speaker 1: Should I call the physics vet or I feel like 328 00:17:40,119 --> 00:17:41,960 Speaker 1: this is a legal trapping no matter what advice I 329 00:17:42,040 --> 00:17:46,080 Speaker 1: give you, I mean, the complicit in your death or 330 00:17:46,400 --> 00:17:48,199 Speaker 1: the death of your neighbors somehow, Well, may it's just 331 00:17:48,240 --> 00:17:52,159 Speaker 1: a theoretical black hole that I have in my theoretical yard. Alright, 332 00:17:52,200 --> 00:17:54,560 Speaker 1: So we're talking about the discovery of black holes, and 333 00:17:54,640 --> 00:17:58,160 Speaker 1: so they were sort of this weird mathematical kind of 334 00:17:58,280 --> 00:18:01,320 Speaker 1: oddity in the equations, and maybe the equations were wrong, 335 00:18:01,400 --> 00:18:03,720 Speaker 1: or maybe these things were real, but people didn't know. 336 00:18:04,119 --> 00:18:05,960 Speaker 1: So what kind of pushed people to think that maybe 337 00:18:05,960 --> 00:18:07,920 Speaker 1: they were real? There was a period in the late 338 00:18:08,000 --> 00:18:11,320 Speaker 1: nineteen fifties when there was a lot of theoretical activity 339 00:18:11,359 --> 00:18:15,240 Speaker 1: because people finally understood theoretically what this might mean. There's 340 00:18:15,240 --> 00:18:17,879 Speaker 1: a guy named David Finkelstein, and he was actually working 341 00:18:17,880 --> 00:18:21,280 Speaker 1: on something totally different. He was trying to understand quantum gravity, 342 00:18:21,359 --> 00:18:23,959 Speaker 1: was trying to bring together quantum mechanics and gravity, and 343 00:18:24,040 --> 00:18:26,399 Speaker 1: he cooked up a really weird system that had some 344 00:18:26,600 --> 00:18:29,840 Speaker 1: gravitational kink in it. And it was a weird system, 345 00:18:29,840 --> 00:18:31,280 Speaker 1: but it gave him an idea. He was like, you 346 00:18:31,320 --> 00:18:34,360 Speaker 1: know what, in my weird system, I had this concept 347 00:18:34,400 --> 00:18:37,240 Speaker 1: of an event horizon where information can go in one 348 00:18:37,280 --> 00:18:39,520 Speaker 1: direction but not the other. And he was looking at 349 00:18:39,760 --> 00:18:42,680 Speaker 1: his weird theory and he thought, you know what, this 350 00:18:42,760 --> 00:18:45,680 Speaker 1: might be what we're talking about in short stiles theory. 351 00:18:45,840 --> 00:18:48,000 Speaker 1: And he went back and he looked at these frozen 352 00:18:48,040 --> 00:18:51,119 Speaker 1: stars and the short siled radius and the singularity in 353 00:18:51,160 --> 00:18:53,680 Speaker 1: the gravitation equations and he said, you know what, that's 354 00:18:53,720 --> 00:18:57,840 Speaker 1: what's happening here. He like theoretically reinterpreted this and said 355 00:18:58,119 --> 00:19:00,719 Speaker 1: this is what an event horizon is. He came at 356 00:19:00,760 --> 00:19:02,800 Speaker 1: it from a different direction. Yeah, he just had like 357 00:19:03,119 --> 00:19:05,719 Speaker 1: a moment of insight, like how to look at these equations. 358 00:19:05,960 --> 00:19:08,919 Speaker 1: But still people thought, all right, well that's cool. This 359 00:19:09,040 --> 00:19:13,320 Speaker 1: makes this weird mathematical curiosity more interesting, Like how weird 360 00:19:13,359 --> 00:19:15,520 Speaker 1: would that be if information it could only flow in 361 00:19:15,600 --> 00:19:19,439 Speaker 1: one direction across a threshold in space? Right? But then 362 00:19:19,480 --> 00:19:21,960 Speaker 1: they started seeing weird stuff out there in the universe 363 00:19:22,160 --> 00:19:25,000 Speaker 1: that slowly built up the evidence that these things could 364 00:19:25,040 --> 00:19:28,240 Speaker 1: be real. And the first thing was the discovery not 365 00:19:28,400 --> 00:19:31,679 Speaker 1: of black holes, but actually of pulsings. These are like 366 00:19:31,760 --> 00:19:35,080 Speaker 1: special stars, right, yeah, these are special stars. There are 367 00:19:35,119 --> 00:19:37,439 Speaker 1: neutron stars. These are stars that are at the end 368 00:19:37,480 --> 00:19:39,680 Speaker 1: of their life, and this is the leftover chord, and 369 00:19:39,960 --> 00:19:42,800 Speaker 1: it's so dense that all the protons and electrons have 370 00:19:42,920 --> 00:19:46,040 Speaker 1: merged together to form neutrons. It's a very dense kind 371 00:19:46,040 --> 00:19:50,560 Speaker 1: of object. But again it was a theoretical object. People thought, well, potentially, 372 00:19:50,600 --> 00:19:53,840 Speaker 1: if you had enough stuff together, collapse into a neutron star, 373 00:19:54,080 --> 00:19:57,680 Speaker 1: but nobody really believed that existed until they were discovered 374 00:19:57,720 --> 00:20:01,119 Speaker 1: in nineteen sixty seven a special version and of them pulsars, 375 00:20:01,400 --> 00:20:04,720 Speaker 1: which rotate and have a very strong beam coming at 376 00:20:04,720 --> 00:20:07,320 Speaker 1: the top of them. We're discovering people thought, oh, my gosh, 377 00:20:07,600 --> 00:20:12,480 Speaker 1: maybe these very massive, gravitationally collapsed objects really do exist 378 00:20:12,560 --> 00:20:15,480 Speaker 1: in the universe, and people started to take these mathematical 379 00:20:15,480 --> 00:20:18,840 Speaker 1: solutions a little bit more seriously. Pulsars are not sort 380 00:20:18,880 --> 00:20:21,000 Speaker 1: of related to black holes, but they are sort of 381 00:20:21,040 --> 00:20:24,520 Speaker 1: extreme and crazy and maybe also kind of like a 382 00:20:24,520 --> 00:20:28,640 Speaker 1: weird equation oddity, and so when they find it, they're like, hey, 383 00:20:28,680 --> 00:20:31,400 Speaker 1: maybe need that applies to black holes too. Yeah, maybe 384 00:20:31,400 --> 00:20:34,760 Speaker 1: we should start taking these gravitational oddities that are theoretical, 385 00:20:34,960 --> 00:20:37,679 Speaker 1: we should start taking them more seriously, because you know, 386 00:20:37,720 --> 00:20:40,800 Speaker 1: if neutron stars are real, maybe black holes are also. 387 00:20:41,080 --> 00:20:43,240 Speaker 1: It's like, hey, he got a Nobel price, I want 388 00:20:43,280 --> 00:20:46,119 Speaker 1: one to Let's dig into this and it's a fascinating 389 00:20:46,119 --> 00:20:47,840 Speaker 1: store because there's a lot of different threads. At the 390 00:20:47,880 --> 00:20:50,360 Speaker 1: same time. You have this theory thread where people are 391 00:20:50,400 --> 00:20:53,520 Speaker 1: finally starting to understand what these equations mean. Then you 392 00:20:53,520 --> 00:20:56,840 Speaker 1: have this thread from the neutron stars where people discovered pulsars, 393 00:20:57,280 --> 00:21:01,199 Speaker 1: and then totally separately, people were launching rockets into the 394 00:21:01,240 --> 00:21:04,760 Speaker 1: atmosphere to try to study X rays, and in White 395 00:21:04,800 --> 00:21:07,399 Speaker 1: Sands Missile based in New Mexico, a couple of folks 396 00:21:07,640 --> 00:21:11,000 Speaker 1: outfitted a rocket with this X ray detector because they 397 00:21:11,000 --> 00:21:13,320 Speaker 1: wanted to see, like what does the sky look like 398 00:21:13,560 --> 00:21:16,879 Speaker 1: in the X ray Because the atmosphere stops a lot 399 00:21:16,880 --> 00:21:19,159 Speaker 1: of X rays from coming down to Earth. So if 400 00:21:19,160 --> 00:21:20,480 Speaker 1: you want to see X rays, you can. I have 401 00:21:20,520 --> 00:21:22,080 Speaker 1: to go out into space, that's right, and it's a 402 00:21:22,119 --> 00:21:24,920 Speaker 1: great opportunity to see something new. It's just to look 403 00:21:24,960 --> 00:21:27,840 Speaker 1: at the universe in a new way. Like we've looked 404 00:21:27,840 --> 00:21:30,960 Speaker 1: at the universe using our eyeballs, and we build telescopes 405 00:21:31,000 --> 00:21:33,439 Speaker 1: that are more powerful to look invisible light. But we 406 00:21:33,480 --> 00:21:36,560 Speaker 1: also like to look at the universe in invisible light, 407 00:21:36,840 --> 00:21:40,200 Speaker 1: you know, infrared or radio waves or X rays, and 408 00:21:40,440 --> 00:21:43,920 Speaker 1: X rays are extra powerful because they come from gas 409 00:21:43,960 --> 00:21:47,359 Speaker 1: that's at millions and millions of degrees. There are things 410 00:21:47,400 --> 00:21:49,919 Speaker 1: out there that emit only in the X rays and 411 00:21:49,960 --> 00:21:52,160 Speaker 1: you can only see their X rays. They don't emit 412 00:21:52,280 --> 00:21:55,200 Speaker 1: visible light. So people thought, well, let's take a look 413 00:21:55,240 --> 00:21:57,960 Speaker 1: at the universe using a new set of eyeballs. So 414 00:21:58,040 --> 00:22:00,119 Speaker 1: they flew these rockets up to the top of the 415 00:22:00,160 --> 00:22:03,320 Speaker 1: atmosphere and outfit of them with X ray detectors. And 416 00:22:03,520 --> 00:22:05,399 Speaker 1: this is not like you know, in orbit. It just 417 00:22:05,440 --> 00:22:09,320 Speaker 1: like goes up. It's sort of suborbital picture. It takes 418 00:22:09,400 --> 00:22:13,720 Speaker 1: selfie and drop takes the university sort of scans the 419 00:22:13,760 --> 00:22:16,120 Speaker 1: sky for like eight degrees and then it comes back. 420 00:22:17,320 --> 00:22:20,040 Speaker 1: I like that. And they saw some really weird stuff. 421 00:22:20,080 --> 00:22:23,680 Speaker 1: They found eight new very bright sources of X rays 422 00:22:23,720 --> 00:22:27,120 Speaker 1: that nobody had ever seen before, like spiked, and they 423 00:22:27,119 --> 00:22:29,000 Speaker 1: could tell where it was coming from. Yeah, they could 424 00:22:29,000 --> 00:22:30,760 Speaker 1: tell where it was coming from. They were like points 425 00:22:30,760 --> 00:22:33,000 Speaker 1: in space. It was like, you know, you develop your 426 00:22:33,000 --> 00:22:35,600 Speaker 1: picture and you see these bright dots in the sky 427 00:22:35,760 --> 00:22:38,639 Speaker 1: and this one sickness X one which turns out to 428 00:22:38,680 --> 00:22:41,560 Speaker 1: historically be the most important was the brightest one. And 429 00:22:41,600 --> 00:22:44,040 Speaker 1: if you look up in the sky, there's nothing there, 430 00:22:44,280 --> 00:22:47,399 Speaker 1: like you don't see anything in the optical. Your eyes 431 00:22:47,400 --> 00:22:50,520 Speaker 1: don't tell you there's anything, But there's an incredible source 432 00:22:50,560 --> 00:22:52,760 Speaker 1: of X rays coming at you from this dot in 433 00:22:52,800 --> 00:22:56,280 Speaker 1: the sky. Interesting, and that's weird. So it's it's not 434 00:22:56,400 --> 00:22:59,560 Speaker 1: emitting visible light, but it's emitting X rays. Yes, And 435 00:22:59,600 --> 00:23:02,119 Speaker 1: that was really weird. So people thought, well, what's there. 436 00:23:02,640 --> 00:23:04,360 Speaker 1: So then these same folks that are like, well, let's 437 00:23:04,359 --> 00:23:06,240 Speaker 1: follow up on this, and they built a satellite with 438 00:23:06,359 --> 00:23:08,600 Speaker 1: NASA and they put it up in space to orbit, 439 00:23:08,800 --> 00:23:11,280 Speaker 1: and this gave them more data and more precision, and 440 00:23:11,280 --> 00:23:13,119 Speaker 1: they were able to figure out exactly where it was 441 00:23:13,160 --> 00:23:17,240 Speaker 1: coming from. This is now nineteen seventy, and they learned 442 00:23:17,240 --> 00:23:20,600 Speaker 1: something else really fascinating about this source was that it 443 00:23:20,640 --> 00:23:23,240 Speaker 1: was variable, Like it wasn't just emitting X rays. It 444 00:23:23,240 --> 00:23:25,000 Speaker 1: would admit a bunch of X rays and then not 445 00:23:25,080 --> 00:23:26,520 Speaker 1: very much, and then a bunch of BAST rays and 446 00:23:26,600 --> 00:23:29,600 Speaker 1: then not very much. It was highly variable, and it 447 00:23:29,680 --> 00:23:32,480 Speaker 1: was variable on a really short time scale. It's not 448 00:23:32,560 --> 00:23:34,480 Speaker 1: like it would take a year to change. It could 449 00:23:34,520 --> 00:23:36,600 Speaker 1: go like on and off in less than a second. 450 00:23:36,760 --> 00:23:39,440 Speaker 1: What and was it consistent or was it sort of random? 451 00:23:39,480 --> 00:23:41,960 Speaker 1: It was sort of random and sporadic. But the fact 452 00:23:42,000 --> 00:23:43,560 Speaker 1: that it would go on and off in like less 453 00:23:43,560 --> 00:23:46,359 Speaker 1: than a second gave them a really, really valuable clue 454 00:23:46,560 --> 00:23:49,560 Speaker 1: about how big it is. Because something that turns on 455 00:23:49,720 --> 00:23:52,920 Speaker 1: and off in less than a second can't actually be 456 00:23:53,000 --> 00:23:56,480 Speaker 1: that large. Why not because of the speed of light. 457 00:23:56,920 --> 00:23:59,440 Speaker 1: Like if this is all caused by a single event, 458 00:23:59,480 --> 00:24:01,439 Speaker 1: you have some event which is causing this thing to 459 00:24:01,480 --> 00:24:04,200 Speaker 1: flare up, then there's a certain amount of time that 460 00:24:04,280 --> 00:24:07,399 Speaker 1: the information has to travel across an object. So that 461 00:24:07,480 --> 00:24:09,760 Speaker 1: limits how big that object can be if it's going 462 00:24:09,800 --> 00:24:13,159 Speaker 1: to sort of operate coherent, Like if it's too big, 463 00:24:13,200 --> 00:24:15,960 Speaker 1: then you would see it fade in and out kind of. 464 00:24:16,040 --> 00:24:17,520 Speaker 1: If it's too big, then they would have like lots 465 00:24:17,560 --> 00:24:19,920 Speaker 1: of different pockets, Right, they have a little pocket over 466 00:24:19,960 --> 00:24:21,960 Speaker 1: here that's doing something, a little pocket over there that's 467 00:24:21,960 --> 00:24:24,800 Speaker 1: doing something. But for an object to act like as one, 468 00:24:24,920 --> 00:24:28,000 Speaker 1: like one coherent source turning on and off, means it 469 00:24:28,000 --> 00:24:30,959 Speaker 1: has to be pretty small because all that stuff has 470 00:24:31,000 --> 00:24:35,320 Speaker 1: to sort of be in communication within light speed, in sync. Right, Yeah, 471 00:24:35,359 --> 00:24:37,199 Speaker 1: it has to be in sync exactly, just like the 472 00:24:37,240 --> 00:24:39,520 Speaker 1: boy band. It has to move in one direction, if 473 00:24:39,520 --> 00:24:43,359 Speaker 1: you know what I'm talking about. Yeah, totally. I'm a 474 00:24:43,400 --> 00:24:49,439 Speaker 1: big fan of black Hole Street Boys. They were the 475 00:24:49,440 --> 00:24:52,120 Speaker 1: best anyway. So they knew that this thing was very powerful, 476 00:24:52,400 --> 00:24:54,400 Speaker 1: and then it had to be smaller than the sun, 477 00:24:54,640 --> 00:24:57,200 Speaker 1: like the time variability of it. Given the clue that 478 00:24:57,320 --> 00:25:00,440 Speaker 1: this thing was like smaller than about ten p the Sun, 479 00:25:00,920 --> 00:25:03,159 Speaker 1: So then that was really interesting because now you know 480 00:25:03,240 --> 00:25:06,040 Speaker 1: you have something They're very bright in the X ray 481 00:25:06,119 --> 00:25:08,480 Speaker 1: and very very small, I see. And it couldn't be 482 00:25:08,560 --> 00:25:11,239 Speaker 1: one of these crazy like neutron stars or did they 483 00:25:11,240 --> 00:25:12,720 Speaker 1: think it was a new kind of star. That was 484 00:25:12,760 --> 00:25:14,840 Speaker 1: the next thing. It's like, well, maybe it's a neutron star. 485 00:25:15,200 --> 00:25:16,760 Speaker 1: And so to figure out whether or not it was 486 00:25:16,800 --> 00:25:18,840 Speaker 1: a neutron star, they had to figure out how heavy 487 00:25:19,000 --> 00:25:22,080 Speaker 1: is it? Because neutron stars have a maximum mass, like 488 00:25:22,160 --> 00:25:24,639 Speaker 1: you can't get a neutron star more than like three 489 00:25:24,760 --> 00:25:26,919 Speaker 1: or four times the mass of the Sun. If they 490 00:25:26,920 --> 00:25:29,240 Speaker 1: get that big, they should collapse to a black hole. 491 00:25:29,920 --> 00:25:31,640 Speaker 1: So the next thing was to figure out like, well 492 00:25:31,640 --> 00:25:35,000 Speaker 1: how heavy is this? And the good news is that 493 00:25:35,080 --> 00:25:38,199 Speaker 1: this X ray source had a star nearby there was 494 00:25:38,240 --> 00:25:41,800 Speaker 1: another a really big star as blue supergiant that was 495 00:25:41,880 --> 00:25:45,080 Speaker 1: near it, that was orbiting around that one was bright 496 00:25:45,320 --> 00:25:47,400 Speaker 1: and that when you can see in the visible and 497 00:25:47,720 --> 00:25:50,199 Speaker 1: so this object, whatever it was that was making the 498 00:25:50,359 --> 00:25:54,440 Speaker 1: X rays, was orbiting around this blue supergiant star. Really 499 00:25:54,480 --> 00:25:57,679 Speaker 1: they're orbiting each other. It's like a binary system. And 500 00:25:57,760 --> 00:25:59,840 Speaker 1: you knew that the X rays were not coming from 501 00:25:59,840 --> 00:26:02,159 Speaker 1: that other star because stars like that can't make X 502 00:26:02,240 --> 00:26:04,760 Speaker 1: rays they're not hot enough. You could tell like their 503 00:26:04,880 --> 00:26:07,440 Speaker 1: X rays coming from this separate thing that's orbiting the star. 504 00:26:08,040 --> 00:26:10,440 Speaker 1: And based on how fast the star and this new 505 00:26:10,480 --> 00:26:13,280 Speaker 1: mystery object we're orbiting each other, you could figure out 506 00:26:13,320 --> 00:26:15,960 Speaker 1: the mass of that mystery Interesting what did they find? 507 00:26:15,960 --> 00:26:18,119 Speaker 1: How massive was it? It was really pretty big. It 508 00:26:18,160 --> 00:26:20,960 Speaker 1: was like fifteen times the mass of our Sun. And 509 00:26:21,040 --> 00:26:24,840 Speaker 1: this new object was orbiting this super giant star like 510 00:26:24,880 --> 00:26:27,919 Speaker 1: every five days. Like this is not you know, a 511 00:26:28,040 --> 00:26:32,359 Speaker 1: year long orbit or something pretty close to each other. Yeah, 512 00:26:32,520 --> 00:26:36,520 Speaker 1: this is like cosmically very violent. And so you knew 513 00:26:36,560 --> 00:26:39,840 Speaker 1: it was very massive but not very large, and you 514 00:26:39,920 --> 00:26:41,800 Speaker 1: knew that it was really dense, and you knew that 515 00:26:41,840 --> 00:26:44,199 Speaker 1: it was dark. And in the end, all of the 516 00:26:44,280 --> 00:26:47,600 Speaker 1: evidence for The observation of black holes basically comes down 517 00:26:47,600 --> 00:26:50,200 Speaker 1: to an argument like that, like, you have a huge 518 00:26:50,200 --> 00:26:52,800 Speaker 1: amount of mass in a small amount of space and 519 00:26:52,840 --> 00:26:56,080 Speaker 1: it's not radiating, so therefore it must be a black hole. 520 00:26:56,560 --> 00:26:58,840 Speaker 1: But the thing itself had to be a black hole, 521 00:26:59,000 --> 00:27:02,080 Speaker 1: because what nutrons rs can't be that heavy. Neutron stars 522 00:27:02,119 --> 00:27:04,479 Speaker 1: cannot be that heavy. If they get any heavier, they 523 00:27:04,480 --> 00:27:09,160 Speaker 1: should collapse gravitationally to being a black hole. Theoretically though, Like, 524 00:27:09,200 --> 00:27:11,360 Speaker 1: but at the time, they didn't know black holes were real, 525 00:27:11,440 --> 00:27:14,040 Speaker 1: so couldn't they just have assumed that it was a 526 00:27:14,200 --> 00:27:17,760 Speaker 1: super duper dense neutron star. Yeah, well, you could rule 527 00:27:17,760 --> 00:27:21,600 Speaker 1: out neutron stars because neutron stars actually do make visible light. 528 00:27:21,680 --> 00:27:24,119 Speaker 1: I mean, they have a surface, and when stuff falls 529 00:27:24,200 --> 00:27:26,560 Speaker 1: under the surface of a neutron star, you can see 530 00:27:26,560 --> 00:27:30,000 Speaker 1: it radiates, right, so neutron stars can be visualized. But 531 00:27:30,119 --> 00:27:31,560 Speaker 1: you're right, you could say, well, how do we know 532 00:27:31,600 --> 00:27:33,320 Speaker 1: it's actually a black hole? How do we know it's 533 00:27:33,359 --> 00:27:37,360 Speaker 1: not something else? If it's just really massive and really small, 534 00:27:37,400 --> 00:27:39,359 Speaker 1: how do you know it is a black hole, not 535 00:27:39,480 --> 00:27:43,280 Speaker 1: some like weird preon star or a quark star or 536 00:27:43,320 --> 00:27:46,960 Speaker 1: some other new kind of non black hole matter, right, 537 00:27:47,119 --> 00:27:51,360 Speaker 1: But the theories back then predicted black holes emitted X rays. 538 00:27:51,440 --> 00:27:53,679 Speaker 1: So the X rays don't actually come from the black 539 00:27:53,680 --> 00:27:57,160 Speaker 1: hole itself. It comes from the gas that's swirling around 540 00:27:57,160 --> 00:27:59,680 Speaker 1: the black hole, the accretion disk. And so what we're 541 00:27:59,720 --> 00:28:02,000 Speaker 1: seeing are not X rays from the black hole, but 542 00:28:02,119 --> 00:28:04,640 Speaker 1: from the gas that's about to go in the black hole. 543 00:28:05,080 --> 00:28:08,000 Speaker 1: The black hole was slurping out gas from this super 544 00:28:08,000 --> 00:28:10,760 Speaker 1: giant blue star that was near it, and there was 545 00:28:10,800 --> 00:28:13,560 Speaker 1: this like stream of gas and there would swirl around 546 00:28:13,560 --> 00:28:15,879 Speaker 1: the black hole, and as it was swirling around, the 547 00:28:15,880 --> 00:28:18,359 Speaker 1: black hole gets rubbed against each other, a lot of 548 00:28:18,359 --> 00:28:21,240 Speaker 1: friction there, and that's when the gas is then emitting 549 00:28:21,480 --> 00:28:24,879 Speaker 1: in these millions of degree situations, is emitting these X rays. 550 00:28:24,880 --> 00:28:26,479 Speaker 1: But did they know that back then? Did they know 551 00:28:26,560 --> 00:28:29,280 Speaker 1: that about the equation discs, that that was all part 552 00:28:29,320 --> 00:28:31,560 Speaker 1: of their model of black holes, That was all part 553 00:28:31,560 --> 00:28:33,560 Speaker 1: of the model of black holes. Yeah, but you know, 554 00:28:33,640 --> 00:28:35,919 Speaker 1: it's still it's a little bit indirect, like how do 555 00:28:35,960 --> 00:28:38,160 Speaker 1: you really know that it's a black hole? Even to 556 00:28:38,280 --> 00:28:41,480 Speaker 1: this day, Like our evidence is limited to basically that 557 00:28:41,600 --> 00:28:44,720 Speaker 1: kind of argument. It's like there's nothing else that we 558 00:28:44,760 --> 00:28:47,680 Speaker 1: can think of that could describe this nothing else that 559 00:28:47,760 --> 00:28:51,080 Speaker 1: could be this dense and this massive and radiate in 560 00:28:51,120 --> 00:28:54,280 Speaker 1: these certain ways and in no other ways. Black holes 561 00:28:54,280 --> 00:28:57,360 Speaker 1: sort of the only candidate we have to me. That's 562 00:28:57,360 --> 00:29:01,400 Speaker 1: not like total slam dunk evidence. You know, it's about 563 00:29:01,400 --> 00:29:03,640 Speaker 1: as good as I think we can get. I'm not criticizing, 564 00:29:03,840 --> 00:29:07,160 Speaker 1: but there's still there's a level of indirection there. It's like, yeah, 565 00:29:07,160 --> 00:29:10,880 Speaker 1: I don't really solved the murder until you've seen the body, right, 566 00:29:10,880 --> 00:29:14,480 Speaker 1: but you can still maybe find a person guilty, the 567 00:29:14,560 --> 00:29:17,480 Speaker 1: stellar object guilty. And you know, there was a lot 568 00:29:17,480 --> 00:29:20,280 Speaker 1: of debate and discussion in the community like is this 569 00:29:20,320 --> 00:29:23,680 Speaker 1: thing real? And you know, like in the early seventies, 570 00:29:23,960 --> 00:29:27,400 Speaker 1: I think most people were convinced in the astrophysics community 571 00:29:27,440 --> 00:29:30,080 Speaker 1: that this was a black hole. But there was one holdout, 572 00:29:30,200 --> 00:29:34,080 Speaker 1: very notable holdout. Who was it well, Stephen Hawking. Stephen 573 00:29:34,120 --> 00:29:36,600 Speaker 1: Hawking in the nineteen seventy four, and he had just 574 00:29:36,680 --> 00:29:39,760 Speaker 1: come up with his theory of like black hole thermodynamics 575 00:29:39,960 --> 00:29:43,200 Speaker 1: and Hawking radiation, and he really moved the whole like 576 00:29:43,400 --> 00:29:47,400 Speaker 1: theoretical field of black hoology I suppose forward, But he 577 00:29:47,520 --> 00:29:49,200 Speaker 1: wasn't sure that it was a black hole, and he 578 00:29:49,240 --> 00:29:52,200 Speaker 1: made sort of a famous bet with Kip Thorne. Hawking 579 00:29:52,240 --> 00:29:54,720 Speaker 1: bet Kip Thorne that it wasn't a black hole? Really, 580 00:29:54,760 --> 00:29:57,360 Speaker 1: what made him think it wasn't What was he skeptical about. 581 00:29:57,680 --> 00:30:00,360 Speaker 1: I'm not sure he was actually skeptical, lay he when 582 00:30:00,360 --> 00:30:02,280 Speaker 1: he finally conceded it, he said that he was just 583 00:30:02,360 --> 00:30:05,320 Speaker 1: hedging his best. But this way either it was a 584 00:30:05,360 --> 00:30:08,120 Speaker 1: black hole, which is awesome for him, or he wont 585 00:30:08,120 --> 00:30:11,000 Speaker 1: to bet against Kip Thorne, which was also awesome for him, 586 00:30:11,000 --> 00:30:14,160 Speaker 1: And so this way he got something. He's playing all 587 00:30:14,200 --> 00:30:18,200 Speaker 1: the angles, Yeah, sort of like Pascal's wager with black holes. 588 00:30:18,520 --> 00:30:20,920 Speaker 1: Maybe he's superstitious. He's like, if I bet against myself, 589 00:30:20,960 --> 00:30:24,840 Speaker 1: maybe he'll come through and then I'll get a Nobel price. Yeah. 590 00:30:24,880 --> 00:30:27,280 Speaker 1: And so that's the early seventies, and we have this 591 00:30:27,360 --> 00:30:30,560 Speaker 1: evidence for a source, you know, that's very intense mass 592 00:30:30,600 --> 00:30:33,840 Speaker 1: and a small space has the right radiation profile. And 593 00:30:33,880 --> 00:30:38,640 Speaker 1: then this one last thread, which is quasars. Quasars are 594 00:30:38,640 --> 00:30:42,640 Speaker 1: these very very bright source of radiation from very deep 595 00:30:42,680 --> 00:30:44,920 Speaker 1: in the universe, and for a long time nobody really 596 00:30:44,960 --> 00:30:47,760 Speaker 1: understood they seemed to be coming from really far away, 597 00:30:48,040 --> 00:30:51,200 Speaker 1: yet they were still really bright, which meant that whatever 598 00:30:51,320 --> 00:30:54,920 Speaker 1: was making them was extraordinarily bright. For a long time, 599 00:30:54,960 --> 00:30:57,600 Speaker 1: nobody really believed They didn't believe that they were black holes. 600 00:30:57,720 --> 00:31:00,960 Speaker 1: That was actually like a coded black hole. No nobody 601 00:31:00,960 --> 00:31:02,560 Speaker 1: even even thought it was black holes. For a while, 602 00:31:02,560 --> 00:31:05,160 Speaker 1: people just didn't even really believe that the data was right. 603 00:31:05,160 --> 00:31:08,080 Speaker 1: They thought, you know, how could something be this bright 604 00:31:08,240 --> 00:31:10,239 Speaker 1: and so far away, because then it had to be 605 00:31:10,360 --> 00:31:14,800 Speaker 1: riduculously bright at its source. But people eventually believed these 606 00:31:14,840 --> 00:31:17,720 Speaker 1: really are super bright sources, and then finally came to 607 00:31:17,800 --> 00:31:22,400 Speaker 1: understand them as supermassive black holes at the centers of galaxies. 608 00:31:23,040 --> 00:31:25,640 Speaker 1: And so this thread of quasars was sort of helped 609 00:31:25,640 --> 00:31:28,080 Speaker 1: along by the discovery of black holes as a real thing. 610 00:31:28,160 --> 00:31:31,120 Speaker 1: People like, oh, well, black holes are real, Maybe we 611 00:31:31,120 --> 00:31:36,760 Speaker 1: can use that to explain quasars. Also, because we seem quasars, 612 00:31:36,920 --> 00:31:40,880 Speaker 1: we just didn't know what could be making that much energy. Yeah, 613 00:31:40,960 --> 00:31:44,280 Speaker 1: and this could explain it. A really dense, compact gravitational 614 00:31:44,360 --> 00:31:48,840 Speaker 1: mass capable of squeezing the gas in its environment enough 615 00:31:48,920 --> 00:31:52,080 Speaker 1: to generate this incredible radiation. And now we know that 616 00:31:52,120 --> 00:31:54,840 Speaker 1: we have one. For example, at the center of our galaxy, 617 00:31:55,200 --> 00:31:57,680 Speaker 1: center of the Milky Way is a huge black hole 618 00:31:57,840 --> 00:32:00,600 Speaker 1: four million times the mass of the Sun. It's called 619 00:32:00,640 --> 00:32:04,600 Speaker 1: Sagittarius a star. It's funny it's called a star there 620 00:32:04,600 --> 00:32:06,720 Speaker 1: because the guy who named it was so excited and 621 00:32:06,760 --> 00:32:10,920 Speaker 1: he thought star made something exciting. What really, Yeah, he 622 00:32:11,000 --> 00:32:14,120 Speaker 1: didn't think of putting an asterix would make people somehow 623 00:32:14,160 --> 00:32:16,360 Speaker 1: suspicious of it. I know in the sports world an 624 00:32:16,360 --> 00:32:20,560 Speaker 1: asterisk means like, well maybe not right, but in chemistry, 625 00:32:20,600 --> 00:32:24,160 Speaker 1: star means excited state. For him, it's like an exclamation mark, 626 00:32:24,280 --> 00:32:27,880 Speaker 1: exclamation yeah, like a smiley face at the end, I 627 00:32:27,960 --> 00:32:36,320 Speaker 1: discovered Sagittarius, a smiley phase, emoji, star emoji, telescope star night. 628 00:32:36,520 --> 00:32:39,320 Speaker 1: So you have all these threads coming together, this theoretical 629 00:32:39,400 --> 00:32:42,360 Speaker 1: understanding of it as an event horizon beyond which no 630 00:32:42,440 --> 00:32:45,520 Speaker 1: information can pass, and then the discovery these X ray 631 00:32:45,600 --> 00:32:49,480 Speaker 1: sources which had no corresponding optical signature, and then come 632 00:32:49,520 --> 00:32:52,160 Speaker 1: together with this line of thinking about quasars, what are 633 00:32:52,200 --> 00:32:55,400 Speaker 1: these weird emitters at the centers of these galaxies? Plus 634 00:32:55,400 --> 00:32:58,920 Speaker 1: trying to prove Stephen hawkingrong. I mean, that's that's some 635 00:32:59,040 --> 00:33:01,360 Speaker 1: motivation right there. Alright, but all of this is still 636 00:33:01,440 --> 00:33:05,600 Speaker 1: sort of circumstantial evidence, And so let's get into how 637 00:33:05,640 --> 00:33:08,720 Speaker 1: we actually see them today. But first let's take another 638 00:33:08,800 --> 00:33:24,600 Speaker 1: quick break, all right, Daniel, So we're we're I guess 639 00:33:24,600 --> 00:33:26,760 Speaker 1: we're in the seventies and the eighties, and we have 640 00:33:26,840 --> 00:33:29,880 Speaker 1: all this evidence for black holes, and there's a lot 641 00:33:29,920 --> 00:33:32,040 Speaker 1: of stuff that we're seeing that could be or would 642 00:33:32,120 --> 00:33:35,520 Speaker 1: be explained by black holes. And also everyone wants Stephen 643 00:33:35,520 --> 00:33:38,560 Speaker 1: Hawking to be wrong. Um, so what sort of sealed 644 00:33:38,600 --> 00:33:41,560 Speaker 1: the deal for black holes? Like, was it us seeing 645 00:33:41,600 --> 00:33:43,520 Speaker 1: them or tend taking a picture last year for the 646 00:33:43,560 --> 00:33:46,880 Speaker 1: first time, or did were we pretty convinced before? Well, 647 00:33:46,880 --> 00:33:49,719 Speaker 1: it's been a sort of slow accumulation of evidence. And 648 00:33:49,800 --> 00:33:51,960 Speaker 1: the best way to convince yourself that something weird is 649 00:33:52,000 --> 00:33:54,600 Speaker 1: real is to see it in lots of different ways, 650 00:33:54,960 --> 00:33:58,040 Speaker 1: because that prevents you from having made one particular mistake 651 00:33:58,160 --> 00:34:01,200 Speaker 1: or misunderstanding one kind of data, or screwing up your 652 00:34:01,280 --> 00:34:04,280 Speaker 1: lenses or something. And so the first piece of evidence 653 00:34:04,480 --> 00:34:07,080 Speaker 1: was you know, this sickness X one, this X ray 654 00:34:07,160 --> 00:34:10,000 Speaker 1: source from a very compact object. But now we have 655 00:34:10,120 --> 00:34:14,839 Speaker 1: several ways, also still indirect, to point to these black holes. 656 00:34:14,840 --> 00:34:16,920 Speaker 1: All right, so what are what are some of these ways? 657 00:34:17,160 --> 00:34:19,600 Speaker 1: Can we lose something out there in space? Or Number 658 00:34:19,600 --> 00:34:21,680 Speaker 1: one is that we started seeing a lot of quasars, 659 00:34:21,719 --> 00:34:26,000 Speaker 1: and by now we've seen like a hundred thousand galactic quaisars. 660 00:34:26,000 --> 00:34:29,120 Speaker 1: And so each of these, yeah, each of these are 661 00:34:29,280 --> 00:34:33,440 Speaker 1: probably a supermassive black hole the center of a galaxy, 662 00:34:33,600 --> 00:34:36,200 Speaker 1: and so we see the radiation from them. You can 663 00:34:36,200 --> 00:34:38,399 Speaker 1: see the accretion disk around some of them if they're 664 00:34:38,400 --> 00:34:41,320 Speaker 1: close enough, really, and so this is pretty strong evidence 665 00:34:41,360 --> 00:34:43,880 Speaker 1: that those black holes exist. You can actually see the 666 00:34:43,960 --> 00:34:46,120 Speaker 1: accretion disk, or you can just see something really bright, 667 00:34:46,160 --> 00:34:48,040 Speaker 1: but you can see something really bright coming from the 668 00:34:48,040 --> 00:34:50,560 Speaker 1: center of the galaxy. And we're talking in a minute 669 00:34:50,600 --> 00:34:53,279 Speaker 1: about the direct imaging of a black hole that came 670 00:34:53,360 --> 00:34:56,000 Speaker 1: up much later. But this is pretty strong evidence for 671 00:34:56,080 --> 00:34:58,840 Speaker 1: sort of black holes to exist in the universe. But 672 00:34:58,920 --> 00:35:01,399 Speaker 1: you know, there's two linds the black holes. There's these 673 00:35:01,480 --> 00:35:04,759 Speaker 1: supermassive black holes at the center of galaxies that are 674 00:35:04,840 --> 00:35:06,960 Speaker 1: very powerful and crazy. And then there's the kind of 675 00:35:06,960 --> 00:35:08,799 Speaker 1: black hole that I think most people think about, like 676 00:35:08,840 --> 00:35:11,319 Speaker 1: a star at the end of its life that collapses 677 00:35:11,360 --> 00:35:13,360 Speaker 1: and turns into a black hole. Those are like the 678 00:35:13,400 --> 00:35:15,520 Speaker 1: pet black holes. Yeah, that's right. Those are the kinds 679 00:35:15,520 --> 00:35:17,680 Speaker 1: you can pick up at the local mall. And we 680 00:35:17,760 --> 00:35:19,279 Speaker 1: think that there are a lot of those, but we've 681 00:35:19,320 --> 00:35:22,600 Speaker 1: only actually ever seen a few because they're much harder 682 00:35:22,640 --> 00:35:25,600 Speaker 1: to spot. So while we've seen like a hundred thousand 683 00:35:25,600 --> 00:35:29,040 Speaker 1: galactic quasars, we only have a few dozen stellar mass 684 00:35:29,080 --> 00:35:31,799 Speaker 1: black holes that we've actually observed. But don't we see 685 00:35:31,840 --> 00:35:34,400 Speaker 1: stars training into black holes a lot, like you know 686 00:35:34,520 --> 00:35:37,319 Speaker 1: these supernova? Don't we see those pretty often? We see 687 00:35:37,320 --> 00:35:40,160 Speaker 1: supernova I mean not that often, but not every supernova 688 00:35:40,200 --> 00:35:43,080 Speaker 1: turns into a black hole. Some of them turn into 689 00:35:43,480 --> 00:35:46,200 Speaker 1: a neutron stars or something else. And so it has 690 00:35:46,239 --> 00:35:48,880 Speaker 1: to be particular sized to turn into a black hole. 691 00:35:49,120 --> 00:35:51,439 Speaker 1: And also you see a supernova, the black hole doesn't 692 00:35:51,440 --> 00:35:55,520 Speaker 1: necessarily form immediately and isn't visible immediately. It's surrounded by 693 00:35:55,560 --> 00:35:58,440 Speaker 1: this huge cloud of stuff still for a while, and 694 00:35:58,520 --> 00:36:01,040 Speaker 1: so it's gonna take a long time for accretion disk 695 00:36:01,080 --> 00:36:04,040 Speaker 1: to sort of gathered together and make the black hole visible. 696 00:36:04,960 --> 00:36:07,400 Speaker 1: I hadn't realized that we have seen many more super 697 00:36:07,400 --> 00:36:10,000 Speaker 1: massive black holes and than the smaller black holes. Yeah, 698 00:36:10,040 --> 00:36:13,440 Speaker 1: these stellar mass black holes are harder to spot, all right, 699 00:36:13,520 --> 00:36:17,040 Speaker 1: So that's one growing body of evidence. What else is there? 700 00:36:17,080 --> 00:36:19,800 Speaker 1: Another indirect way to see a black hole is to 701 00:36:19,840 --> 00:36:22,439 Speaker 1: look at the stars around them. Like if you see 702 00:36:22,480 --> 00:36:26,080 Speaker 1: nothing in the sky, but then you see things swirling 703 00:36:26,120 --> 00:36:29,200 Speaker 1: around it as if there was a very strong amount 704 00:36:29,200 --> 00:36:31,279 Speaker 1: of gravity there, then you can make sort of the 705 00:36:31,280 --> 00:36:33,640 Speaker 1: same argument. You can say, well, there has to be 706 00:36:33,840 --> 00:36:36,880 Speaker 1: a big blob of stuff there that's providing the gravity. 707 00:36:36,960 --> 00:36:39,040 Speaker 1: And we see this, for example again at the center 708 00:36:39,040 --> 00:36:41,960 Speaker 1: of our own galaxy. We can watch the path of 709 00:36:42,040 --> 00:36:44,520 Speaker 1: stars as they near the center of the galaxy and 710 00:36:44,560 --> 00:36:47,280 Speaker 1: we can tell that they are bent in a curve 711 00:36:47,840 --> 00:36:50,960 Speaker 1: as if there was an incredibly strong gravitational source there. 712 00:36:50,960 --> 00:36:53,160 Speaker 1: We can't see the black hole directly, of course, but 713 00:36:53,200 --> 00:36:55,400 Speaker 1: we can see the motion of stars around it, right, 714 00:36:55,440 --> 00:36:58,000 Speaker 1: And you can find movies of this online probably right. 715 00:36:58,080 --> 00:37:01,360 Speaker 1: It's like a take a picture basically a black screen, 716 00:37:01,640 --> 00:37:04,399 Speaker 1: but you see stars kind of moving and going really 717 00:37:04,440 --> 00:37:06,920 Speaker 1: fast around nothingness. Yeah, there's a group at U c 718 00:37:07,040 --> 00:37:09,200 Speaker 1: l A that's been watching the center of our galaxy 719 00:37:09,280 --> 00:37:12,239 Speaker 1: for like two decades now and plotting the motion of 720 00:37:12,280 --> 00:37:14,480 Speaker 1: these stars. And there's one star in particular, it's called 721 00:37:14,680 --> 00:37:17,719 Speaker 1: S two, which passes really close to the center of 722 00:37:17,760 --> 00:37:20,319 Speaker 1: the galaxy and then whips around who has sort of 723 00:37:20,360 --> 00:37:24,000 Speaker 1: a shorter period And because they've been watching for two decades. 724 00:37:24,280 --> 00:37:26,680 Speaker 1: You can see like complete orbits of some of these stars, 725 00:37:26,760 --> 00:37:28,960 Speaker 1: and then you can do the calculation and you can 726 00:37:28,960 --> 00:37:31,560 Speaker 1: tell how much mass there is, and because the star 727 00:37:31,600 --> 00:37:34,279 Speaker 1: has passed so close to the center, you can get 728 00:37:34,280 --> 00:37:36,960 Speaker 1: a sense for how small it has to be right there. 729 00:37:37,239 --> 00:37:40,320 Speaker 1: The stars trajectory limits the size of this thing, and 730 00:37:40,360 --> 00:37:42,200 Speaker 1: so at some point you're like, well, there's a huge 731 00:37:42,200 --> 00:37:44,600 Speaker 1: amount of gravity and a small amount of space boom 732 00:37:44,840 --> 00:37:47,759 Speaker 1: black right, and so wow, we can actually point a 733 00:37:47,760 --> 00:37:49,600 Speaker 1: telescope at the center of our galaxy and get a 734 00:37:49,600 --> 00:37:51,880 Speaker 1: picture like that. Yeah, you can. You can see these stars. 735 00:37:51,960 --> 00:37:54,880 Speaker 1: It's difficult because there's so much gas and dust and 736 00:37:54,880 --> 00:37:56,759 Speaker 1: so you have to sort of see through that and 737 00:37:56,840 --> 00:37:59,880 Speaker 1: look in the near infrared light and also use like 738 00:38:00,120 --> 00:38:03,880 Speaker 1: fancy adaptive optics. But you can actually see that. So 739 00:38:04,200 --> 00:38:05,839 Speaker 1: we do have kind of a pet black hole inner 740 00:38:05,840 --> 00:38:09,000 Speaker 1: back yard. Yeah. Yeah, it's a tens of thousands of 741 00:38:09,040 --> 00:38:11,359 Speaker 1: light years away. So if your backyard is that big, 742 00:38:11,360 --> 00:38:14,680 Speaker 1: then yes, you have a black hole inside, or maybe 743 00:38:14,719 --> 00:38:18,640 Speaker 1: we're the pets of the black hole. And then recently 744 00:38:18,640 --> 00:38:21,840 Speaker 1: we have a total different kind of evidence for black holes, 745 00:38:22,160 --> 00:38:24,960 Speaker 1: and that's the gravitational waves that come when they collide 746 00:38:25,000 --> 00:38:27,640 Speaker 1: with each other. Right, that's what Lego discovered recently, right, 747 00:38:27,680 --> 00:38:29,479 Speaker 1: a couple of years ago. That's right. If black holes 748 00:38:29,480 --> 00:38:31,839 Speaker 1: get close enough to each other, then they slurp each 749 00:38:31,880 --> 00:38:34,920 Speaker 1: other in. But usually they have some like angular momentum 750 00:38:34,960 --> 00:38:37,400 Speaker 1: around each other, so they can't just like approach head on. 751 00:38:37,680 --> 00:38:39,800 Speaker 1: It's like a near miss. And then they swing around 752 00:38:39,800 --> 00:38:42,480 Speaker 1: and they come back around and they swirl a little bit, 753 00:38:42,640 --> 00:38:45,000 Speaker 1: just like stuff going down the toilet bowl. It swirls 754 00:38:45,040 --> 00:38:48,080 Speaker 1: a little bit until eventually it finally collapses into a 755 00:38:48,120 --> 00:38:51,839 Speaker 1: single black hole. And in those last moments when they're 756 00:38:51,840 --> 00:38:55,200 Speaker 1: swirling around each other really really fast, then the gravity 757 00:38:55,239 --> 00:38:57,719 Speaker 1: is changing really really quickly. So the gravitational field goes 758 00:38:57,960 --> 00:38:59,839 Speaker 1: up and down and up and down, up and down 759 00:39:00,160 --> 00:39:02,560 Speaker 1: as the black hole swirls around. And that's what we 760 00:39:02,600 --> 00:39:05,160 Speaker 1: call a gravitational way. Right. It's kind of pulling and 761 00:39:05,200 --> 00:39:09,319 Speaker 1: pulling and pushing really quickly and making waves in the 762 00:39:09,360 --> 00:39:11,880 Speaker 1: fabric of spacetime. That's right, because if you think about 763 00:39:11,920 --> 00:39:16,320 Speaker 1: gravity not as like a gravitational field, but instead curving space, 764 00:39:16,360 --> 00:39:19,120 Speaker 1: which is what general relativity tells us, then what happens 765 00:39:19,200 --> 00:39:22,080 Speaker 1: is you're seeing these ripples in space time, and that's 766 00:39:22,080 --> 00:39:24,040 Speaker 1: what we saw here on Earth using Lego, and we 767 00:39:24,080 --> 00:39:26,360 Speaker 1: have a whole episode about that. But the point is 768 00:39:26,400 --> 00:39:29,360 Speaker 1: that there's a signature there in this shaking of space. 769 00:39:29,680 --> 00:39:31,600 Speaker 1: It starts, then it goes faster and faster and faster 770 00:39:31,640 --> 00:39:34,840 Speaker 1: and faster, boom, until the black holes collide. And that 771 00:39:34,960 --> 00:39:37,279 Speaker 1: looks a certain way, and you expect it to look 772 00:39:37,360 --> 00:39:39,360 Speaker 1: a certain way if you see two black holes, and 773 00:39:39,360 --> 00:39:41,560 Speaker 1: it looks different if you see like a black hole 774 00:39:41,640 --> 00:39:44,520 Speaker 1: eating a neutron star. And so this is really pretty 775 00:39:44,520 --> 00:39:46,600 Speaker 1: good evidence that those black holes are real, that they're 776 00:39:46,600 --> 00:39:49,479 Speaker 1: out right, and so that's pretty recent. And then even 777 00:39:49,480 --> 00:39:52,480 Speaker 1: more recently, we actually took a picture of a black hole. Yeah, 778 00:39:52,560 --> 00:39:56,000 Speaker 1: we did this direct image from the event horizon telescope. 779 00:39:56,320 --> 00:39:59,040 Speaker 1: It looked a black hole the center of a nearby 780 00:39:59,120 --> 00:40:02,920 Speaker 1: galaxy M eighty seven, which has a really super duper 781 00:40:03,000 --> 00:40:05,560 Speaker 1: black hole at its center, and they try to like 782 00:40:05,600 --> 00:40:08,279 Speaker 1: focus in and they try to separate the part of 783 00:40:08,320 --> 00:40:10,400 Speaker 1: the black hole that's the very center of the actual 784 00:40:10,400 --> 00:40:13,680 Speaker 1: event horizon from the gas that's around it, and we 785 00:40:13,800 --> 00:40:15,600 Speaker 1: got a picture, like there's an image you can look 786 00:40:15,680 --> 00:40:19,040 Speaker 1: up online and see it, which sort of proves all 787 00:40:19,120 --> 00:40:21,799 Speaker 1: these theories. Yeah, you have a picture. It looks sort 788 00:40:21,800 --> 00:40:24,560 Speaker 1: of like, you know, a fuzzy donut or something. It's 789 00:40:24,560 --> 00:40:27,680 Speaker 1: not too spectacular unless you like really understand the context 790 00:40:27,680 --> 00:40:29,920 Speaker 1: of it, which is what you're seeing is the gas 791 00:40:29,920 --> 00:40:32,640 Speaker 1: swirling around the black hole. And then at the very 792 00:40:32,640 --> 00:40:36,040 Speaker 1: center you see the shadow. You see nothing, right, there's 793 00:40:36,080 --> 00:40:38,359 Speaker 1: nothing there. I mean, you see the hole, you see 794 00:40:38,680 --> 00:40:40,640 Speaker 1: the whole, and it's black. Yeah, you see the whole 795 00:40:40,680 --> 00:40:44,200 Speaker 1: and it's black. And you know what's different about that blackness, 796 00:40:44,239 --> 00:40:46,760 Speaker 1: And just like the random blackness of a patch of space, 797 00:40:46,960 --> 00:40:49,960 Speaker 1: it's really the stuff around it. It's this incredibly hot 798 00:40:50,360 --> 00:40:53,600 Speaker 1: gas that's swirling around and it looks exactly the way 799 00:40:53,640 --> 00:40:56,600 Speaker 1: you would expect. And it's impossible to get that configuration 800 00:40:56,880 --> 00:41:01,600 Speaker 1: of high speed gas emitting X rays without huge gravitational mass. 801 00:41:01,600 --> 00:41:04,759 Speaker 1: So we know there's a gravitational mass right in the 802 00:41:04,800 --> 00:41:07,080 Speaker 1: center of that picture where the black part is right, 803 00:41:07,160 --> 00:41:10,000 Speaker 1: but there's no light being admitted. So again it's a 804 00:41:10,040 --> 00:41:12,560 Speaker 1: direct picture of what a black hole would look like. 805 00:41:13,000 --> 00:41:15,560 Speaker 1: Is it actually a black hole or something else that 806 00:41:15,600 --> 00:41:18,000 Speaker 1: doesn't admit light? You know, then you get into semantics 807 00:41:18,000 --> 00:41:20,520 Speaker 1: about what is and is not a black hole. It's 808 00:41:20,560 --> 00:41:24,920 Speaker 1: something very dense, very compact, very strong gravitationally that does 809 00:41:25,000 --> 00:41:27,040 Speaker 1: not admit any visible light. Well, I'm gonna make a 810 00:41:27,040 --> 00:41:29,239 Speaker 1: bed with you, Daniel, just like Stephen Hawkins made a bit. 811 00:41:29,400 --> 00:41:32,680 Speaker 1: We'll bid you that it is actually a giant, fuzzy doughnut. Okay, 812 00:41:33,239 --> 00:41:35,399 Speaker 1: And how are you going to prove that you're gonna 813 00:41:35,400 --> 00:41:39,479 Speaker 1: take a trip out there and take a bite. Well, 814 00:41:39,480 --> 00:41:42,160 Speaker 1: we may never set a lot of When that image 815 00:41:42,160 --> 00:41:44,920 Speaker 1: came out, I saw people online taking pictures of Crispy 816 00:41:45,000 --> 00:41:48,279 Speaker 1: Kreams and saying, hey, look my picture of Krispy Kreme 817 00:41:48,320 --> 00:41:51,279 Speaker 1: looks just like this crazy discovery. How come I'm not 818 00:41:51,320 --> 00:41:55,640 Speaker 1: getting any press by the Science News. But it's fun 819 00:41:55,640 --> 00:41:57,200 Speaker 1: to actually look at that picture and to think about, 820 00:41:57,200 --> 00:41:59,200 Speaker 1: like what am I seeing? And you know, if you 821 00:41:59,200 --> 00:42:01,200 Speaker 1: look at the very sent tour of it, you're looking 822 00:42:01,320 --> 00:42:05,000 Speaker 1: at the event horizon itself. Right, There's no photons come 823 00:42:05,040 --> 00:42:08,520 Speaker 1: to your eyeballs from the very center because any photon 824 00:42:08,960 --> 00:42:10,880 Speaker 1: that could would have had to come out of the 825 00:42:10,920 --> 00:42:13,600 Speaker 1: black hole. And so that's impossible, right, So it is 826 00:42:13,680 --> 00:42:17,040 Speaker 1: like a black hole, and and it does, and in 827 00:42:17,080 --> 00:42:20,120 Speaker 1: subtle ways too. I heard that it really confirms a 828 00:42:20,160 --> 00:42:22,839 Speaker 1: lot of our theories about what's happening around a black hole, 829 00:42:22,920 --> 00:42:24,759 Speaker 1: like one side of it is brighter than the other 830 00:42:25,200 --> 00:42:27,520 Speaker 1: side of the doughnut because the light is going faster 831 00:42:27,719 --> 00:42:30,880 Speaker 1: when one side and not the other. So it really 832 00:42:30,920 --> 00:42:34,840 Speaker 1: does sort of confirm and and look like what we predicted. 833 00:42:34,920 --> 00:42:38,560 Speaker 1: Like in the movies Interstellar, they sort of simulated black 834 00:42:38,560 --> 00:42:41,040 Speaker 1: holes and they made up pictures of it, and it's 835 00:42:41,120 --> 00:42:42,759 Speaker 1: the real one sort of looks like that. Yeah, and 836 00:42:42,800 --> 00:42:45,279 Speaker 1: it's amazing. And remember that what you're seeing is not 837 00:42:45,360 --> 00:42:47,920 Speaker 1: what's there. You're looking at an image. Just like when 838 00:42:47,960 --> 00:42:51,640 Speaker 1: you look through distorted glass outside the trees look all 839 00:42:51,640 --> 00:42:54,440 Speaker 1: wibbly and wobbly and whatever. That's not what's actually happening. 840 00:42:54,719 --> 00:42:57,120 Speaker 1: That's the image you're seeing. So that's what's happening here. 841 00:42:57,160 --> 00:42:59,600 Speaker 1: And the reason you're seeing an image enough, just you 842 00:42:59,640 --> 00:43:02,600 Speaker 1: know what's there is that space is being bent, right, 843 00:43:02,719 --> 00:43:05,360 Speaker 1: the environment around a black hole. Space is curved and 844 00:43:05,400 --> 00:43:08,719 Speaker 1: so light doesn't travel in straight lines. And so they 845 00:43:08,800 --> 00:43:11,719 Speaker 1: predicted this image, as you're saying, they predicted, if you 846 00:43:11,760 --> 00:43:13,759 Speaker 1: have a black hole with an acretion disc around it, 847 00:43:13,960 --> 00:43:16,160 Speaker 1: what would you see, what would it look like? And 848 00:43:16,200 --> 00:43:19,640 Speaker 1: they predicted all these distortions by retracing all those photons, 849 00:43:19,920 --> 00:43:23,160 Speaker 1: and as you said, what we see is what they expected, 850 00:43:23,200 --> 00:43:25,759 Speaker 1: and so that's pretty good confirmation that they understand the 851 00:43:25,760 --> 00:43:27,880 Speaker 1: physics of what's happening there. So do you feel like 852 00:43:27,920 --> 00:43:30,200 Speaker 1: the picture was kind of the nail in the coffin 853 00:43:30,280 --> 00:43:34,040 Speaker 1: that people finally said, yes, now we can rest easy 854 00:43:34,400 --> 00:43:37,400 Speaker 1: and know for sure that black holes are real? Or 855 00:43:37,520 --> 00:43:39,879 Speaker 1: were people pretty convinced before we saw the picture. People 856 00:43:39,880 --> 00:43:41,799 Speaker 1: were pretty convinced the black holes were real before we 857 00:43:41,840 --> 00:43:44,040 Speaker 1: saw the picture. The picture is like an even more 858 00:43:44,120 --> 00:43:48,799 Speaker 1: stringent test in a new, fascinating and frankly visually appealing 859 00:43:48,880 --> 00:43:51,880 Speaker 1: way of the black hole theory. So I think, you know, 860 00:43:51,960 --> 00:43:55,480 Speaker 1: since the mid nineteventies, black holes have been generally accepted 861 00:43:55,520 --> 00:43:57,920 Speaker 1: as real, but they just get cooler and cooler as 862 00:43:57,960 --> 00:44:00,239 Speaker 1: we learn more and more about them. Kind of guess 863 00:44:00,280 --> 00:44:03,239 Speaker 1: it's you know, it's really amazing to think not just 864 00:44:03,400 --> 00:44:05,719 Speaker 1: the kind of the long path that we've taken here, 865 00:44:05,800 --> 00:44:09,440 Speaker 1: like seeing it in the equations, coming up with solutions, 866 00:44:09,640 --> 00:44:13,279 Speaker 1: finding circumstantial evidence, but just to think that, you know, 867 00:44:13,440 --> 00:44:17,880 Speaker 1: these crazy ideas are real. You know that space really 868 00:44:17,920 --> 00:44:21,399 Speaker 1: does kind of form these pockets where nothing can come out, 869 00:44:21,600 --> 00:44:24,880 Speaker 1: and that they can exist, and that you can actually 870 00:44:24,960 --> 00:44:27,880 Speaker 1: kind of go out there and touching them, be around them. Yeah, 871 00:44:27,920 --> 00:44:30,480 Speaker 1: and it makes you wonder about the sort of primacy 872 00:44:30,520 --> 00:44:33,440 Speaker 1: of mathematics, because you know, all these ideas came from 873 00:44:33,480 --> 00:44:36,960 Speaker 1: just following the mathematics. We expressed our physical laws in 874 00:44:37,040 --> 00:44:39,320 Speaker 1: terms of math, and we followed the consequences, and we 875 00:44:39,400 --> 00:44:41,200 Speaker 1: got this weird result and then it turns out to 876 00:44:41,239 --> 00:44:43,840 Speaker 1: be real. It makes you wonder, like, is math just 877 00:44:43,960 --> 00:44:46,880 Speaker 1: something in our heads or is it like fundamental to 878 00:44:46,920 --> 00:44:50,040 Speaker 1: the universe itself, because it seems like the universe is 879 00:44:50,080 --> 00:44:54,480 Speaker 1: following these mathematical rules regardless of their absurtainty. Are you 880 00:44:54,520 --> 00:44:57,759 Speaker 1: thinking math is better than physics, Doyle, I know that 881 00:44:57,920 --> 00:45:00,080 Speaker 1: all of my colleagues in the math department find to 882 00:45:00,120 --> 00:45:04,799 Speaker 1: be more fundamental than physics. But we all know love 883 00:45:04,880 --> 00:45:09,279 Speaker 1: is the true fundamental power in the universe, according to 884 00:45:09,880 --> 00:45:14,200 Speaker 1: all according to the original boy band the Beatles, I 885 00:45:14,280 --> 00:45:16,160 Speaker 1: was just about to say the same thing. And remember 886 00:45:16,200 --> 00:45:18,600 Speaker 1: a lot of the listeners suggested that we could see 887 00:45:18,640 --> 00:45:21,520 Speaker 1: black holes by seeing their lensing, Like if a black 888 00:45:21,520 --> 00:45:23,680 Speaker 1: hole past in front of another star, you would see 889 00:45:23,680 --> 00:45:27,240 Speaker 1: it distorting. And that's true. Theoretically, we just haven't observed 890 00:45:27,320 --> 00:45:30,040 Speaker 1: that yet, and so that's a possibility something we might 891 00:45:30,080 --> 00:45:31,799 Speaker 1: get to see in the future, and that would be 892 00:45:31,840 --> 00:45:34,799 Speaker 1: a very nice additional piece of evidence. But there haven't 893 00:45:34,800 --> 00:45:38,480 Speaker 1: been any micro lensing events observed yet. Okay, but we've 894 00:45:38,520 --> 00:45:41,520 Speaker 1: seen it in other ways for sure. Yeah, we've seen 895 00:45:41,560 --> 00:45:43,440 Speaker 1: it in lots of ways. Yeah, But that's just something 896 00:45:43,480 --> 00:45:46,520 Speaker 1: to look forward to. That's something you the listener out there, 897 00:45:46,760 --> 00:45:49,200 Speaker 1: might be the first person to ever come right, So 898 00:45:49,360 --> 00:45:52,439 Speaker 1: keep looking up at the stars and don't look away. 899 00:45:53,680 --> 00:45:56,360 Speaker 1: All right. Well, we hope you enjoyed that. Thanks for 900 00:45:56,400 --> 00:45:58,560 Speaker 1: joining us, Thanks for tuning in, and thanks for sending 901 00:45:58,640 --> 00:46:01,520 Speaker 1: us your questions and sharing your curiosity with us, even 902 00:46:01,560 --> 00:46:04,239 Speaker 1: if we do sometimes go down a black hole. See 903 00:46:04,239 --> 00:46:14,560 Speaker 1: you next time. Thanks for listening, and remember that. Daniel 904 00:46:14,600 --> 00:46:17,120 Speaker 1: and Jorge Explain the Universe is a production of I 905 00:46:17,360 --> 00:46:20,759 Speaker 1: Heart Radio. For more podcast from my Heart Radio, visit 906 00:46:20,800 --> 00:46:24,319 Speaker 1: the I Heart Radio Apple Apple Podcasts, or wherever you 907 00:46:24,400 --> 00:46:25,920 Speaker 1: listen to your favorite shows.