1 00:00:08,760 --> 00:00:11,280 Speaker 1: Or hey, does your family have any pets these days? 2 00:00:11,480 --> 00:00:13,680 Speaker 1: We have a wild rabbit that les to hang out 3 00:00:13,800 --> 00:00:16,040 Speaker 1: in our yard. Does that count? Are you it's pet 4 00:00:16,200 --> 00:00:20,759 Speaker 1: or is it yours? That's a great question. I'll have 5 00:00:20,800 --> 00:00:23,119 Speaker 1: to ask the rabbit. Do you have a dog? Right? Yes, 6 00:00:23,200 --> 00:00:25,920 Speaker 1: we have a wonderful little dog named Pepito, an immigrant 7 00:00:25,920 --> 00:00:29,480 Speaker 1: from Incinada. Now, is he called Pepita because he's he's 8 00:00:29,520 --> 00:00:33,160 Speaker 1: actually peppit or or a seed? He is quite peppy, 9 00:00:33,320 --> 00:00:35,120 Speaker 1: but he is not a seed, but he came with 10 00:00:35,159 --> 00:00:37,360 Speaker 1: that name, so we don't actually know why he was 11 00:00:37,400 --> 00:00:40,199 Speaker 1: called Peppita. But interestingly, he does seem to violate the 12 00:00:40,280 --> 00:00:43,839 Speaker 1: laws of physics. Wait, what what do you mean your 13 00:00:43,880 --> 00:00:47,680 Speaker 1: dog travels back in time? Is it actually from the teacher? No, 14 00:00:47,920 --> 00:00:51,200 Speaker 1: he's amazingly a short haired dog, but seems to shed 15 00:00:51,360 --> 00:00:54,960 Speaker 1: enough hair that we find these incredible fur balls around 16 00:00:54,960 --> 00:00:57,640 Speaker 1: the house. And that is why we don't have a pet. 17 00:00:59,240 --> 00:01:01,920 Speaker 1: Does a dog actually clean up after itself at least? Oh? 18 00:01:01,960 --> 00:01:04,920 Speaker 1: Absolutely not. He just seems to turn dog food into fur. 19 00:01:05,240 --> 00:01:07,360 Speaker 1: But how does that violate the laws of physics? Because 20 00:01:07,400 --> 00:01:09,640 Speaker 1: I swear the fur balls he produced I have more 21 00:01:09,720 --> 00:01:12,880 Speaker 1: masks than the food we're feeding them. What Maybe the 22 00:01:12,920 --> 00:01:15,280 Speaker 1: dog is from the future. Maybe dogs know more about 23 00:01:15,280 --> 00:01:18,600 Speaker 1: physics than we do. That's an extraordinary claim. Daniel, are 24 00:01:18,640 --> 00:01:21,000 Speaker 1: you sure about this? Have you actually run the experiments? 25 00:01:21,000 --> 00:01:23,319 Speaker 1: If you wait, how much food you've give him versus 26 00:01:23,480 --> 00:01:26,320 Speaker 1: you measured the mass these furballs. I'm still waiting to 27 00:01:26,360 --> 00:01:28,640 Speaker 1: hear back on my grant proposal from the Daniel Science 28 00:01:28,680 --> 00:01:33,640 Speaker 1: Foundation to study your dog. It's very niche organization. Sounds 29 00:01:33,680 --> 00:01:35,600 Speaker 1: like you have to work on a no hair theorem 30 00:01:35,720 --> 00:01:53,240 Speaker 1: for your dog. Hi am poor handmade cartoonists and the 31 00:01:53,240 --> 00:01:56,520 Speaker 1: co author of Frequently Asked Questions about the Universe. Hi. 32 00:01:56,680 --> 00:01:59,480 Speaker 1: I'm Daniel. I'm a particle physicist and a professor at 33 00:01:59,560 --> 00:02:02,560 Speaker 1: uc or Rhyne, and I'm no longer the hairiest thing 34 00:02:02,640 --> 00:02:05,440 Speaker 1: in my family. Oh that's good. Who's the Who's the 35 00:02:05,520 --> 00:02:08,359 Speaker 1: next in line for your title? The dog is number one, 36 00:02:08,480 --> 00:02:11,680 Speaker 1: and I'm number two, and who's number three? I think 37 00:02:11,720 --> 00:02:15,960 Speaker 1: I want to answer that question exactly. Some things are 38 00:02:15,960 --> 00:02:18,040 Speaker 1: best left of mystery in this universe. I believe it 39 00:02:18,120 --> 00:02:21,040 Speaker 1: that as a mystery in the listeners imagination. Welcome to 40 00:02:21,040 --> 00:02:24,119 Speaker 1: our podcast. Daniel and Jorge Explain the Universe, a production 41 00:02:24,200 --> 00:02:26,720 Speaker 1: of I Heart Radio, in which we dig into the 42 00:02:26,800 --> 00:02:31,440 Speaker 1: hairiest tangly mysteries about the universe. We want to understand 43 00:02:31,520 --> 00:02:34,440 Speaker 1: how everything works. We want to pull it apart and 44 00:02:34,520 --> 00:02:37,520 Speaker 1: straighten it out for you and for us. We want 45 00:02:37,560 --> 00:02:39,560 Speaker 1: to walk you right up to the place where our 46 00:02:39,600 --> 00:02:44,200 Speaker 1: brains get twisted into not trying to understand how this 47 00:02:44,360 --> 00:02:47,359 Speaker 1: universe works, how we can describe it all using simple 48 00:02:47,480 --> 00:02:50,320 Speaker 1: mathematical equations, and how we can talk about it to 49 00:02:50,400 --> 00:02:53,320 Speaker 1: each other, to other physicists, and to you and to 50 00:02:53,440 --> 00:02:57,240 Speaker 1: your dog. Maybe because it is a pretty incredible universe. 51 00:02:57,280 --> 00:02:59,560 Speaker 1: It's a dog gone universe. And we love to answer 52 00:02:59,639 --> 00:03:03,480 Speaker 1: questions here on the podcast, all kinds of questions, amazing, incredible, 53 00:03:03,639 --> 00:03:06,359 Speaker 1: deep questions about the universe, and also pet questions that 54 00:03:06,440 --> 00:03:09,240 Speaker 1: people have about how things work, and sometimes questions about 55 00:03:09,280 --> 00:03:11,360 Speaker 1: their pets. I think if you offered my dog like 56 00:03:11,400 --> 00:03:14,320 Speaker 1: a scratch on the head or the answer to one 57 00:03:14,320 --> 00:03:16,760 Speaker 1: of the deepest questions in the universe, probably go for 58 00:03:16,800 --> 00:03:18,640 Speaker 1: the scratch on the head. Maybe a scratch on the 59 00:03:18,639 --> 00:03:21,200 Speaker 1: head is the answer to everything, Daniel. Seems like a 60 00:03:21,240 --> 00:03:24,360 Speaker 1: pretty simple answer but deep profound at the same time. 61 00:03:24,360 --> 00:03:26,400 Speaker 1: We all want a little scratch in our hands maybe 62 00:03:26,400 --> 00:03:29,040 Speaker 1: the answer is the sort of scratch on that internal 63 00:03:29,160 --> 00:03:31,919 Speaker 1: itch in your mind, the one that makes you curious 64 00:03:31,919 --> 00:03:34,520 Speaker 1: about how everything works. Or maybe it's all relative as 65 00:03:34,560 --> 00:03:37,160 Speaker 1: Einstein set you know, to dog, Maybe a scratch on 66 00:03:37,200 --> 00:03:39,680 Speaker 1: the head is the answer to the universe. Well, we 67 00:03:39,720 --> 00:03:41,840 Speaker 1: already know the answer to life, the universe and everything. 68 00:03:42,000 --> 00:03:43,960 Speaker 1: That's forty two. We just need to know what the 69 00:03:44,040 --> 00:03:46,840 Speaker 1: question was. How many scratches to your dog do you 70 00:03:46,840 --> 00:03:49,120 Speaker 1: have to give to for it to be happy? Definitely 71 00:03:49,200 --> 00:03:52,400 Speaker 1: more than forty two. I'm on like forty two never 72 00:03:52,440 --> 00:03:55,320 Speaker 1: seems to lose interest. Sounds like you have a greedy pet. 73 00:03:55,480 --> 00:03:58,400 Speaker 1: Petpito is a wonderful addition to our family. We do 74 00:03:58,520 --> 00:04:00,880 Speaker 1: like to answer questions here in the podcast, and we 75 00:04:01,000 --> 00:04:03,880 Speaker 1: like to answer questions not just that people have in 76 00:04:03,960 --> 00:04:06,600 Speaker 1: mind that are they're curious about it, but also questions 77 00:04:06,600 --> 00:04:09,400 Speaker 1: that even physicists are answering at the cutting edge of 78 00:04:09,440 --> 00:04:12,120 Speaker 1: our knowledge of the universe. That's right. The goal of 79 00:04:12,160 --> 00:04:15,680 Speaker 1: physics is not just to explain why cannonballs fly over 80 00:04:15,840 --> 00:04:18,960 Speaker 1: castle walls or why the Earth goes around the Sun, 81 00:04:19,279 --> 00:04:23,440 Speaker 1: but to explain everything in the universe. We seek a unified, 82 00:04:23,560 --> 00:04:27,240 Speaker 1: holistic description of the entire universe in terms of a 83 00:04:27,440 --> 00:04:31,560 Speaker 1: simple equation the basic rules by which the universe runs, 84 00:04:31,680 --> 00:04:33,560 Speaker 1: and that means that we have a pretty tall order. 85 00:04:33,640 --> 00:04:37,159 Speaker 1: We have to explain everything that's out there. One thing 86 00:04:37,200 --> 00:04:39,839 Speaker 1: that breaks the rule means the rule is not the 87 00:04:39,960 --> 00:04:42,000 Speaker 1: right rule. So we go out there and look for 88 00:04:42,000 --> 00:04:45,840 Speaker 1: the most extreme, the craziest, the bonkers situations where our 89 00:04:46,040 --> 00:04:50,200 Speaker 1: understanding of the universe bends and breaks and snaps. That 90 00:04:50,320 --> 00:04:52,840 Speaker 1: also gives us an opportunity to be creative and think 91 00:04:52,880 --> 00:04:56,760 Speaker 1: about what is out there beyond our understanding. Yeah, because 92 00:04:56,800 --> 00:04:59,679 Speaker 1: there are still big questions about the universe, big holes 93 00:04:59,720 --> 00:05:02,200 Speaker 1: in our a theory of how everything works. May one 94 00:05:02,200 --> 00:05:04,479 Speaker 1: of the biggest holes in our theory and our understanding 95 00:05:04,480 --> 00:05:07,239 Speaker 1: of the universe is actually a hole, or at least 96 00:05:07,279 --> 00:05:09,720 Speaker 1: we call it a hole. These objects that we call 97 00:05:09,880 --> 00:05:12,839 Speaker 1: black holes are an enduring mystery and really capture the 98 00:05:12,880 --> 00:05:16,360 Speaker 1: fascination not just of scientists but of the general public 99 00:05:16,440 --> 00:05:19,240 Speaker 1: because they are so weird. We've been studying what we 100 00:05:19,279 --> 00:05:21,840 Speaker 1: think our black holes for a few decades now, and 101 00:05:21,920 --> 00:05:25,320 Speaker 1: yet deep questions remain about what might be inside them 102 00:05:25,400 --> 00:05:28,359 Speaker 1: and if they are in fact black holes after all, 103 00:05:28,520 --> 00:05:31,560 Speaker 1: you mean, they might not be holes. Maybe they're more 104 00:05:31,600 --> 00:05:33,760 Speaker 1: like a ditch, Is that what you're saying, more like 105 00:05:33,800 --> 00:05:36,840 Speaker 1: a dog, like something a dog would do in your 106 00:05:36,880 --> 00:05:39,320 Speaker 1: yard to bury a bone. Well, they are very frustrating 107 00:05:39,360 --> 00:05:43,279 Speaker 1: to study because you cannot see them directly because they 108 00:05:43,320 --> 00:05:46,039 Speaker 1: are black, and so proving that something is a black 109 00:05:46,040 --> 00:05:49,320 Speaker 1: hole is really quite challenging because you have to develop 110 00:05:49,360 --> 00:05:51,720 Speaker 1: theories for how a black hole would look different from 111 00:05:51,800 --> 00:05:54,800 Speaker 1: some other idea that also looks black. And you can't, 112 00:05:54,839 --> 00:05:58,200 Speaker 1: of course go inside a black hole. So any proof 113 00:05:58,240 --> 00:06:01,160 Speaker 1: that a black hole exists has to come from the outside, 114 00:06:01,200 --> 00:06:03,680 Speaker 1: which means it has to be a little bit indirect. 115 00:06:03,800 --> 00:06:06,320 Speaker 1: That forces us to develop like clever theories for what 116 00:06:06,560 --> 00:06:08,839 Speaker 1: might be going on inside and to try to find 117 00:06:08,920 --> 00:06:12,800 Speaker 1: hints for how that inside might somehow affect the outside 118 00:06:12,839 --> 00:06:14,960 Speaker 1: where we live. You have to say, Daniel, I felt 119 00:06:14,960 --> 00:06:16,960 Speaker 1: a little betray when you told me that black holes 120 00:06:17,040 --> 00:06:19,240 Speaker 1: might not exist. I feel like we've been talking about 121 00:06:19,279 --> 00:06:21,520 Speaker 1: them as if they exist for so long and then 122 00:06:21,560 --> 00:06:24,600 Speaker 1: suddenly tell me that it's just kind of a little 123 00:06:24,600 --> 00:06:26,279 Speaker 1: bit of a theory right now, we don't actually know 124 00:06:26,440 --> 00:06:30,359 Speaker 1: they exist. Yeah, Well, there's always nuance to this understanding, right, Like, 125 00:06:30,440 --> 00:06:32,360 Speaker 1: in the end, what do we really know about the 126 00:06:32,440 --> 00:06:35,640 Speaker 1: nature of the universe. We have experiments which verify our models, 127 00:06:35,680 --> 00:06:39,080 Speaker 1: but there are always questions there. There's always a level 128 00:06:39,120 --> 00:06:42,040 Speaker 1: of refinement. There's always more to learn about what's really 129 00:06:42,080 --> 00:06:44,880 Speaker 1: going on out there in the universe. And black holes 130 00:06:44,920 --> 00:06:49,680 Speaker 1: are very slippery because they are so indirect. Unlike electrons 131 00:06:49,800 --> 00:06:52,480 Speaker 1: or other things. You can't observe them directly. You can 132 00:06:52,520 --> 00:06:55,080 Speaker 1: only see their influence on the parts of the universe 133 00:06:55,080 --> 00:06:57,640 Speaker 1: that are near them. Well, that's a philosophical question. Can 134 00:06:57,640 --> 00:07:00,560 Speaker 1: a black hole be slippery? You lose grasp of a 135 00:07:00,600 --> 00:07:05,120 Speaker 1: black hole? I guess you studied it with physics. Theoretically 136 00:07:05,160 --> 00:07:07,960 Speaker 1: and conceptually, they are very slippery. It's hard to hold 137 00:07:08,000 --> 00:07:09,920 Speaker 1: a black hole in your mind. And you know, we 138 00:07:09,960 --> 00:07:12,480 Speaker 1: don't even really have a great idea for what a 139 00:07:12,600 --> 00:07:16,000 Speaker 1: black hole is, put aside all the crazy alternative ideas. 140 00:07:16,360 --> 00:07:19,080 Speaker 1: Even the concept of a black hole is not super 141 00:07:19,160 --> 00:07:22,440 Speaker 1: well defined right now in modern physics, because we have 142 00:07:22,480 --> 00:07:26,160 Speaker 1: two descriptions of the universe, quantum mechanics and general relativity, 143 00:07:26,400 --> 00:07:29,240 Speaker 1: and they disagree about what might be happening at the 144 00:07:29,280 --> 00:07:31,760 Speaker 1: heart of a black hole. Yeah, it's hard to hold 145 00:07:31,760 --> 00:07:33,760 Speaker 1: a black hole in your mind, and also in your hand. 146 00:07:33,800 --> 00:07:37,440 Speaker 1: I hear, that's a bad idea, not recommended. Leave that 147 00:07:37,480 --> 00:07:39,560 Speaker 1: black hole at the dollar store. Even if it's just 148 00:07:39,600 --> 00:07:41,560 Speaker 1: a dollar, it's not worth it. Can you play catch 149 00:07:41,640 --> 00:07:44,120 Speaker 1: with your pet with a black hole? Depends on how 150 00:07:44,200 --> 00:07:45,960 Speaker 1: much you like your pet. I guess my pet does 151 00:07:46,040 --> 00:07:48,520 Speaker 1: seem like a black hole. He just like inhales. All 152 00:07:48,520 --> 00:07:51,200 Speaker 1: of that dog food is incredible, and those head scratches 153 00:07:51,280 --> 00:07:53,480 Speaker 1: as well, I'm sure. But it is interesting that black 154 00:07:53,520 --> 00:07:55,960 Speaker 1: holes may not be actually black holes. They could be 155 00:07:56,040 --> 00:08:00,200 Speaker 1: something else. Physicists think, maybe something fuzzy, because in the 156 00:08:00,280 --> 00:08:02,760 Speaker 1: end we are left to infer what might be in 157 00:08:02,800 --> 00:08:07,040 Speaker 1: those crazy dark patches of space that we can't see directly. 158 00:08:07,400 --> 00:08:09,760 Speaker 1: So theorists have been very creative coming up with all 159 00:08:09,880 --> 00:08:13,040 Speaker 1: sorts of alternative suggestions for what might be sitting there 160 00:08:13,080 --> 00:08:15,400 Speaker 1: in the blackness to be On the podcast, we'll be 161 00:08:15,440 --> 00:08:24,960 Speaker 1: asking the question, what if black holes are actually fuzzballs? 162 00:08:26,600 --> 00:08:30,280 Speaker 1: Daniel at these fuzzballs or fun balls? Are they fun fuzzball? 163 00:08:30,440 --> 00:08:32,760 Speaker 1: I don't think they would be very fun to fall into, 164 00:08:33,320 --> 00:08:36,319 Speaker 1: even if they are actually part of the universe. It's 165 00:08:36,360 --> 00:08:38,440 Speaker 1: never fun to fall into a hole, but they are 166 00:08:38,480 --> 00:08:41,200 Speaker 1: fun to think about and to imagine, and all the 167 00:08:41,400 --> 00:08:44,800 Speaker 1: artists conceptions of fuzzballs I fund on the internet are 168 00:08:44,840 --> 00:08:47,600 Speaker 1: pretty fun to look at. I think anything on the 169 00:08:47,600 --> 00:08:49,840 Speaker 1: Internet is probably fun to look at. Out to a 170 00:08:49,920 --> 00:08:52,880 Speaker 1: point perhaps to be careful about googling fuzzy balls on 171 00:08:52,920 --> 00:08:56,040 Speaker 1: the internet, though, or any kind of balls really, or 172 00:08:56,040 --> 00:08:59,920 Speaker 1: really anything on the Internet. Be careful of the Internet 173 00:09:00,000 --> 00:09:04,360 Speaker 1: in general. You might fall into a black hole looking 174 00:09:04,400 --> 00:09:07,000 Speaker 1: up random things. But as usually, we were wondering how 175 00:09:07,000 --> 00:09:09,679 Speaker 1: many people out there had considered the question where their 176 00:09:09,679 --> 00:09:12,920 Speaker 1: black holes could actually be fuzzballs. I imagine this is 177 00:09:12,920 --> 00:09:15,319 Speaker 1: not a question people ask themselves every day. That's the 178 00:09:15,400 --> 00:09:18,080 Speaker 1: job of physics, though, right to raise the deep dark 179 00:09:18,160 --> 00:09:21,360 Speaker 1: questions about the universe, sorry, the deep dark questions, and 180 00:09:21,440 --> 00:09:24,280 Speaker 1: the fuzzy questions as well. Daniel went out there into 181 00:09:24,320 --> 00:09:28,360 Speaker 1: the Internet to ask people what is a fuzzball? So 182 00:09:28,440 --> 00:09:31,400 Speaker 1: thanks very much everybody who volunteers for these. If you 183 00:09:31,440 --> 00:09:34,200 Speaker 1: would like to participate for a future episode so that 184 00:09:34,240 --> 00:09:37,880 Speaker 1: other people can hear your ideas about some difficult questions 185 00:09:37,880 --> 00:09:40,400 Speaker 1: in physics, please don't be shy. Right to us two 186 00:09:40,480 --> 00:09:43,560 Speaker 1: questions at Daniel and Jorge dot com. Here's what people 187 00:09:43,600 --> 00:09:46,199 Speaker 1: have to say, possible is a type of baseball that 188 00:09:46,400 --> 00:09:52,640 Speaker 1: it's playing the windowsill. And I'm sure I'm right, but 189 00:09:54,080 --> 00:09:59,480 Speaker 1: it's not this type of baseball, not you asking me about. 190 00:10:00,480 --> 00:10:04,120 Speaker 1: And I'm really curious what would be it? So what 191 00:10:04,280 --> 00:10:08,200 Speaker 1: is fusiball? Fussiball? It sounds like something a cat would 192 00:10:08,240 --> 00:10:11,400 Speaker 1: choke up. I've heard of the no hair theorem for 193 00:10:11,640 --> 00:10:15,360 Speaker 1: black holes, so I'm guessing a fuzzball is the inverse 194 00:10:15,480 --> 00:10:19,680 Speaker 1: theorem for white holes. A fuzzball is a little bit 195 00:10:19,840 --> 00:10:23,520 Speaker 1: of lint that you pick off your sweater. I don't 196 00:10:23,600 --> 00:10:25,360 Speaker 1: know what a fuzzible is, but if I had to 197 00:10:25,400 --> 00:10:31,120 Speaker 1: take a guess, I think it's a collection of nucleons um. 198 00:10:31,280 --> 00:10:34,520 Speaker 1: I don't know, all right, A lot of people associated 199 00:10:34,559 --> 00:10:37,320 Speaker 1: this with pets as well. I didn't give people clues 200 00:10:37,320 --> 00:10:39,240 Speaker 1: about black holes. I just wanted to know if they 201 00:10:39,240 --> 00:10:42,960 Speaker 1: had heard the idea of a physics fuzzball. Someone thought 202 00:10:42,960 --> 00:10:45,160 Speaker 1: it was maybe a type of pitch that you do 203 00:10:45,240 --> 00:10:48,520 Speaker 1: in baseball. Isn't they also a drink? Isn't there a 204 00:10:48,559 --> 00:10:51,319 Speaker 1: drink called a fuzzball or something? Everything is a drink 205 00:10:51,400 --> 00:10:54,960 Speaker 1: these days? Some people they did associated with maybe black holes, right, 206 00:10:55,000 --> 00:10:59,160 Speaker 1: They mentioned no hair theorem. Yeah, that's another tortured analogy 207 00:10:59,280 --> 00:11:02,520 Speaker 1: in physics whether black holes have hair or not. So 208 00:11:02,640 --> 00:11:04,880 Speaker 1: fuzzballs are sort of the other extreme. They're like the 209 00:11:04,960 --> 00:11:08,960 Speaker 1: hairiest possibility for a black hole. That doesn't necessarily make 210 00:11:09,040 --> 00:11:13,280 Speaker 1: them white holes. Though someone mentioned cats that they like 211 00:11:13,400 --> 00:11:16,599 Speaker 1: the balls that cats regurgitate, yet another reason not to 212 00:11:16,679 --> 00:11:19,120 Speaker 1: have pets. That's are wonderful additions to the family. Man, 213 00:11:19,200 --> 00:11:21,559 Speaker 1: I encourage everybody out there to adopt a dog, or 214 00:11:21,600 --> 00:11:24,560 Speaker 1: a cat or a wild rabbit. So this is an 215 00:11:24,600 --> 00:11:27,720 Speaker 1: interesting question. Are black holes actually fastballs? I'm curious to 216 00:11:27,760 --> 00:11:29,920 Speaker 1: know how this came up, Like who's that in their 217 00:11:29,960 --> 00:11:31,520 Speaker 1: couch one day and thought, hey, I wonder if a 218 00:11:31,520 --> 00:11:33,560 Speaker 1: black hole could be a fuzzball. Well, there's a big 219 00:11:33,640 --> 00:11:37,040 Speaker 1: opportunity there in physics to solve one of the deepest 220 00:11:37,120 --> 00:11:41,679 Speaker 1: outstanding questions, which is who describes the universe that we 221 00:11:41,760 --> 00:11:45,120 Speaker 1: live in. Is it general relativity that tells us that 222 00:11:45,200 --> 00:11:50,200 Speaker 1: space is smooth and continuous and classical, that objects move 223 00:11:50,240 --> 00:11:54,080 Speaker 1: in smooth paths through that space, or is it quantum 224 00:11:54,080 --> 00:11:57,520 Speaker 1: mechanics that tells us that everything is discreet and that 225 00:11:57,600 --> 00:12:02,120 Speaker 1: objects don't have smooth classical paths. They have probabilities to 226 00:12:02,160 --> 00:12:04,320 Speaker 1: be here and then probabilities to be there, but they 227 00:12:04,320 --> 00:12:07,080 Speaker 1: don't have to go from here to there, and that 228 00:12:07,200 --> 00:12:10,760 Speaker 1: space itself might actually be discreete. These two things are 229 00:12:10,760 --> 00:12:12,760 Speaker 1: in conflict at the heart of a black hole. The 230 00:12:12,840 --> 00:12:16,760 Speaker 1: description of a black hole in general relativity is inconsistent 231 00:12:16,920 --> 00:12:20,000 Speaker 1: with our understanding of quantum mechanics. So there's definitely an 232 00:12:20,040 --> 00:12:23,679 Speaker 1: opportunity here to be creative. Well, at least the conflict 233 00:12:23,720 --> 00:12:25,520 Speaker 1: is inside of what we think might be a black hole. 234 00:12:25,559 --> 00:12:28,120 Speaker 1: We don't know exactly. We don't know what's out there 235 00:12:28,120 --> 00:12:29,680 Speaker 1: in the universe, but whatever is out there in the 236 00:12:29,720 --> 00:12:33,120 Speaker 1: universe has to be following some rules, right. We think 237 00:12:33,200 --> 00:12:36,280 Speaker 1: that the universe does follow laws, and that we can 238 00:12:36,360 --> 00:12:41,280 Speaker 1: discover those through creativity and experimentation. And so something is 239 00:12:41,320 --> 00:12:43,600 Speaker 1: happening out there. And if we could only see what 240 00:12:43,640 --> 00:12:45,520 Speaker 1: was going on at the heart of a black hole 241 00:12:45,640 --> 00:12:49,160 Speaker 1: or whatever thing is there in those black spots in space, 242 00:12:49,280 --> 00:12:51,280 Speaker 1: then we could get a clue as to what rules 243 00:12:51,360 --> 00:12:53,520 Speaker 1: it's following. All right, Well, let's dig into it, and 244 00:12:53,600 --> 00:12:55,920 Speaker 1: let's start with the basics. I guess for those listeners 245 00:12:56,000 --> 00:12:58,720 Speaker 1: that are not so familiar with black holes, Daniel, what 246 00:12:58,760 --> 00:13:00,800 Speaker 1: are the basics of black holes, Why are they? Why 247 00:13:00,800 --> 00:13:02,640 Speaker 1: do we think we've seen them? So it comes out 248 00:13:02,679 --> 00:13:05,880 Speaker 1: of predictions from general relativity. About a hundred years ago, 249 00:13:06,160 --> 00:13:09,920 Speaker 1: Einstein developed his theory that gravity is not a force 250 00:13:10,080 --> 00:13:13,200 Speaker 1: between two objects with mass like Newton thought, where the 251 00:13:13,200 --> 00:13:15,960 Speaker 1: Earth's gravity, for example, pulls on an apple or the 252 00:13:16,000 --> 00:13:19,240 Speaker 1: Sun's gravity pulls on the Earth. Instead, Einstein said that 253 00:13:19,440 --> 00:13:22,000 Speaker 1: space is bent by the presence of mass. But you 254 00:13:22,080 --> 00:13:25,120 Speaker 1: can't see this bending directly, Like you have a chunk 255 00:13:25,160 --> 00:13:27,280 Speaker 1: of space in front of you. It would look the 256 00:13:27,320 --> 00:13:30,120 Speaker 1: same if it was curved or not curved, until you 257 00:13:30,120 --> 00:13:32,800 Speaker 1: try to pass something through it. You shine light beams 258 00:13:32,840 --> 00:13:35,200 Speaker 1: through space that's not curved, for example, and they just 259 00:13:35,280 --> 00:13:37,720 Speaker 1: go through parallel. You shine light beams through space that 260 00:13:37,960 --> 00:13:41,360 Speaker 1: is curved, then they change direction. But because we can't 261 00:13:41,400 --> 00:13:44,839 Speaker 1: see that curvature directly, like with our own eyes, then 262 00:13:44,880 --> 00:13:47,360 Speaker 1: it looks like there's a force there. It's sort of 263 00:13:47,400 --> 00:13:50,480 Speaker 1: like if you were watching a soccer game and you 264 00:13:50,520 --> 00:13:52,920 Speaker 1: could only see the ball and not the players, you 265 00:13:52,920 --> 00:13:55,520 Speaker 1: would imagine, oh, there's something out there applying a force 266 00:13:55,600 --> 00:13:58,200 Speaker 1: to the ball because it's changing direction, right, And the 267 00:13:58,240 --> 00:14:01,360 Speaker 1: same way we see things moving paths that don't seem 268 00:14:01,559 --> 00:14:03,800 Speaker 1: natural to us. The Earth moves in a path around 269 00:14:03,840 --> 00:14:06,240 Speaker 1: the Sun, so we imagine a force of gravity, and 270 00:14:06,280 --> 00:14:09,240 Speaker 1: actuality is just space being curved. So Einstein came up 271 00:14:09,280 --> 00:14:13,080 Speaker 1: with this description of gravity as bending of space, and 272 00:14:13,080 --> 00:14:15,600 Speaker 1: people played with it and thought, well, how much can 273 00:14:15,720 --> 00:14:17,960 Speaker 1: space get bent? And it's about a hundred years ago. 274 00:14:18,040 --> 00:14:20,800 Speaker 1: People came up with this solution to Einstein's equations that 275 00:14:20,920 --> 00:14:23,720 Speaker 1: predicted that if you've got enough mass in one little spot, 276 00:14:23,760 --> 00:14:26,800 Speaker 1: it would compactify itself so much that space would curve 277 00:14:26,920 --> 00:14:29,240 Speaker 1: infinitely and the things that got really close to it 278 00:14:29,280 --> 00:14:32,280 Speaker 1: would be trapped forever. It's kind of natural to think 279 00:14:32,280 --> 00:14:34,600 Speaker 1: of gravity as a force, right, I mean, we sort 280 00:14:34,600 --> 00:14:38,000 Speaker 1: of looked at electromagnetic forces. We saw magnets, you know, 281 00:14:38,040 --> 00:14:40,000 Speaker 1: repel each other. We see that you can push against 282 00:14:40,040 --> 00:14:42,640 Speaker 1: your chair and things like that. Those are still forces, right, 283 00:14:42,800 --> 00:14:44,720 Speaker 1: and so it was I guess natural to think of 284 00:14:44,760 --> 00:14:47,320 Speaker 1: gravity also. And it is natural to think of gravity 285 00:14:47,360 --> 00:14:50,040 Speaker 1: also as a force. Yeah, there are definitely forces in 286 00:14:50,080 --> 00:14:52,920 Speaker 1: the universe, and we've been able to describe them with theories, 287 00:14:52,960 --> 00:14:56,520 Speaker 1: first classical theories like of electromagnetism and now quantum field 288 00:14:56,520 --> 00:15:00,160 Speaker 1: theories of electromagnetism. So it's reasonable to say a b 289 00:15:00,320 --> 00:15:03,440 Speaker 1: gravity is a force. Einstein's description of gravity is that 290 00:15:03,480 --> 00:15:06,280 Speaker 1: it's not a force, is that it's a bending of space. 291 00:15:06,480 --> 00:15:09,400 Speaker 1: It's a fictitious force that comes out of our inability 292 00:15:09,480 --> 00:15:12,440 Speaker 1: to see that bending, and fictitious forces like this occur, 293 00:15:12,480 --> 00:15:15,320 Speaker 1: and lots of other situations. Imagine, for example, you are 294 00:15:15,360 --> 00:15:17,080 Speaker 1: on a Merry go Round and you try to throw 295 00:15:17,120 --> 00:15:19,240 Speaker 1: a ball to your friend. Well, the ball wouldn't move 296 00:15:19,280 --> 00:15:22,000 Speaker 1: in what looks to you like a straight line because 297 00:15:22,040 --> 00:15:24,840 Speaker 1: the Merry go Round is spinning, and so you might imagine, oh, 298 00:15:24,920 --> 00:15:28,240 Speaker 1: there's some force they're pushing the ball sideways. It's a 299 00:15:28,280 --> 00:15:30,960 Speaker 1: fictitious force. It's just because your Merry go Round is spinning. 300 00:15:31,080 --> 00:15:33,880 Speaker 1: Is no real force there. And so that's just Einstein's 301 00:15:33,880 --> 00:15:36,520 Speaker 1: description of it. And you know, that works really well, 302 00:15:36,520 --> 00:15:39,000 Speaker 1: and it predicts lots of things in our universe, and 303 00:15:39,000 --> 00:15:41,880 Speaker 1: it's been tested out the wazoo. But fundamentally it is 304 00:15:41,920 --> 00:15:45,320 Speaker 1: inconsistent with quantum mechanics. And yet as we look out 305 00:15:45,360 --> 00:15:48,080 Speaker 1: into the universe, we do see some evidence for these 306 00:15:48,120 --> 00:15:50,520 Speaker 1: black holes being out there. Well, I think that that's 307 00:15:50,520 --> 00:15:53,200 Speaker 1: why you brought up general relativity, is because black holes 308 00:15:53,200 --> 00:15:56,680 Speaker 1: were originally thought of because of this idea of relativity, right, 309 00:15:57,360 --> 00:15:59,720 Speaker 1: I mean, it was initially kind of a theoretical concept. 310 00:16:00,080 --> 00:16:03,160 Speaker 1: For about fifty years, it was only theoretical. People were 311 00:16:03,160 --> 00:16:05,800 Speaker 1: playing around with this in the math you know, Einstein 312 00:16:05,880 --> 00:16:08,200 Speaker 1: came up with this description of the universe, and then 313 00:16:08,200 --> 00:16:10,760 Speaker 1: people are explored it mathematically and said, well, what else 314 00:16:10,800 --> 00:16:13,560 Speaker 1: can this do? What is this predict about the universe? 315 00:16:13,600 --> 00:16:15,680 Speaker 1: And this is a pretty basic process in physics, right. 316 00:16:15,680 --> 00:16:17,600 Speaker 1: We come up with a description of what we see, 317 00:16:17,640 --> 00:16:20,040 Speaker 1: what we think we understand, and then we tested in 318 00:16:20,080 --> 00:16:24,320 Speaker 1: other scenarios. We try to understand its limitations and its strengths. 319 00:16:24,400 --> 00:16:27,000 Speaker 1: And so people playing with the mathematics came up with 320 00:16:27,040 --> 00:16:29,920 Speaker 1: this prediction of a singularity, although it took them a 321 00:16:29,960 --> 00:16:33,040 Speaker 1: long time to even develop the mathematical concept of an 322 00:16:33,040 --> 00:16:37,040 Speaker 1: event horizon, that something coming close to this object in 323 00:16:37,160 --> 00:16:40,120 Speaker 1: space would be trapped and never be able to escape. 324 00:16:40,160 --> 00:16:42,240 Speaker 1: And it was more than fifty years before we saw 325 00:16:42,240 --> 00:16:44,840 Speaker 1: sort of any evidence that these things were actually out 326 00:16:44,840 --> 00:16:47,360 Speaker 1: there in the universe. But I wonder if someone have 327 00:16:47,560 --> 00:16:49,520 Speaker 1: come up with the idea of a black hole without 328 00:16:49,560 --> 00:16:52,520 Speaker 1: general relativity, Like can you just imagine something having so 329 00:16:52,640 --> 00:16:55,760 Speaker 1: much density and so much maths that the force of 330 00:16:55,800 --> 00:16:58,520 Speaker 1: gravity is too much even for light. Yeah, the idea 331 00:16:58,800 --> 00:17:01,760 Speaker 1: of an object so massive that it might pull light 332 00:17:01,840 --> 00:17:05,000 Speaker 1: to its surface pre dates general relativity. It comes from 333 00:17:05,000 --> 00:17:07,600 Speaker 1: like the middle of the seventeen hundreds, where people were 334 00:17:07,640 --> 00:17:10,800 Speaker 1: thinking about very massive objects. So even in Newtonian gravity, 335 00:17:10,800 --> 00:17:14,640 Speaker 1: people were wondering, like, is it possible to pull on light? Remember, 336 00:17:14,640 --> 00:17:17,000 Speaker 1: back then we didn't even know what light was. The 337 00:17:17,000 --> 00:17:19,879 Speaker 1: theory of light as electromagnetic radiation didn't come to like 338 00:17:19,960 --> 00:17:22,720 Speaker 1: a hundred years after that. So people have been playing 339 00:17:22,720 --> 00:17:26,040 Speaker 1: around with these ideas before relativity. Wait what So then 340 00:17:26,119 --> 00:17:27,919 Speaker 1: people came up with black holes in the middle of 341 00:17:27,960 --> 00:17:31,119 Speaker 1: the seventeen century. Not the name maybe, but you know, 342 00:17:31,119 --> 00:17:33,800 Speaker 1: if you imagine a planet so dense that it trapped light, 343 00:17:33,840 --> 00:17:36,240 Speaker 1: then that's basically a black hole, isn't it. Yeah. It 344 00:17:36,320 --> 00:17:39,120 Speaker 1: was seventy four a guy named John Mitchell was wondering 345 00:17:39,200 --> 00:17:42,080 Speaker 1: what happens if you make a star so massive, it's 346 00:17:42,119 --> 00:17:46,159 Speaker 1: gravity so strong that essentially it's escape velocity would be 347 00:17:46,240 --> 00:17:48,040 Speaker 1: at the speed of light. He was just doing a 348 00:17:48,080 --> 00:17:50,640 Speaker 1: mental thought experiment, and he thought, well, any light that 349 00:17:50,720 --> 00:17:53,080 Speaker 1: leaves that would not be able to escape, and it 350 00:17:53,119 --> 00:17:56,560 Speaker 1: would essentially come back to the star. He called these 351 00:17:56,600 --> 00:18:01,360 Speaker 1: things dark stars, not black holes. M interesting. Wow, So 352 00:18:01,440 --> 00:18:04,240 Speaker 1: maybe we should just call black holes dark stars, although 353 00:18:04,440 --> 00:18:06,960 Speaker 1: dark stars are now used to describe something else that 354 00:18:07,040 --> 00:18:09,199 Speaker 1: we talked about on the podcast recently, which is a 355 00:18:09,200 --> 00:18:11,679 Speaker 1: different quantum mechanical version of a black hole. So that 356 00:18:11,800 --> 00:18:14,879 Speaker 1: name has already been used twice. It's in there like 357 00:18:14,920 --> 00:18:18,160 Speaker 1: an International Copyright Office for physics names. If you file 358 00:18:18,240 --> 00:18:21,040 Speaker 1: an nobody else can use that name. Shouldn't there be one? 359 00:18:21,560 --> 00:18:23,040 Speaker 1: Like why if I come up with a new consept 360 00:18:23,080 --> 00:18:25,000 Speaker 1: then I call it a black hole? Can I do that? 361 00:18:25,280 --> 00:18:27,199 Speaker 1: You can try. I don't know if anybody is going 362 00:18:27,280 --> 00:18:29,160 Speaker 1: to use it. It's sort of the wild wild West 363 00:18:29,200 --> 00:18:32,440 Speaker 1: out there. All right. Well that's the basics of black holes, 364 00:18:32,600 --> 00:18:35,200 Speaker 1: and so let's get into whether we see black holes 365 00:18:35,200 --> 00:18:37,280 Speaker 1: and whether they're even holes at all. They might not 366 00:18:37,359 --> 00:18:40,480 Speaker 1: be holes, they might be fuzzy balls. But first let's 367 00:18:40,480 --> 00:18:55,720 Speaker 1: take a quick break. Alright, we're talking about pets. I 368 00:18:55,760 --> 00:18:59,520 Speaker 1: guess holes and black holes and fuzzballs. Somehow it all 369 00:18:59,560 --> 00:19:02,879 Speaker 1: makes sense because pets are fuzzy usually, and black holes 370 00:19:02,920 --> 00:19:05,600 Speaker 1: are bad pets. Please don't get a black hole for 371 00:19:05,640 --> 00:19:09,320 Speaker 1: your pet. Yeah, it'll eat everything, I mean literally everything 372 00:19:09,359 --> 00:19:11,399 Speaker 1: in your house, and then your neighbor's house, and then 373 00:19:11,440 --> 00:19:14,080 Speaker 1: your neighbor's neighbor's house, and then your neighbor's neighbor's pets 374 00:19:14,160 --> 00:19:16,679 Speaker 1: as well. But yeah, we're talking about whether black holes 375 00:19:16,680 --> 00:19:19,639 Speaker 1: are actually hold. Maybe they're not black holes, and they 376 00:19:19,720 --> 00:19:22,280 Speaker 1: might be something called a fuzzball. Is that the actual 377 00:19:22,280 --> 00:19:25,920 Speaker 1: physics name fuzzball? That is the actual physics name a fuzzball. 378 00:19:25,920 --> 00:19:27,560 Speaker 1: And so with the whole judgment until you hear more 379 00:19:27,600 --> 00:19:29,439 Speaker 1: about what it is. But I think it's not a 380 00:19:29,520 --> 00:19:33,840 Speaker 1: terrible description of this theoretical idea. Well, let's find out. 381 00:19:33,880 --> 00:19:35,920 Speaker 1: Now we're talking about the basics of a black hole, 382 00:19:36,000 --> 00:19:39,080 Speaker 1: which is like a play sorce. Space is so bent 383 00:19:39,200 --> 00:19:42,159 Speaker 1: by the density of matter that an energy that it 384 00:19:42,240 --> 00:19:45,399 Speaker 1: sucks up even light. Now, Daniel, we've seen black hole now, right, 385 00:19:45,520 --> 00:19:47,879 Speaker 1: a couple of years ago. Now, they've had pictures of 386 00:19:47,960 --> 00:19:49,960 Speaker 1: black holes, so we know they exist. There are pictures 387 00:19:49,960 --> 00:19:53,680 Speaker 1: on the internet of black holes that look like big, 388 00:19:53,720 --> 00:19:56,320 Speaker 1: giant black holes. Yeah, if there are pictures on the Internet, 389 00:19:56,359 --> 00:19:58,800 Speaker 1: then it must be true. Right, I've also seen pictures 390 00:19:58,800 --> 00:20:01,480 Speaker 1: of Jedi warriors on the internet. Are you saying NASA 391 00:20:01,560 --> 00:20:05,119 Speaker 1: put out tissues from images. No, Unfortunately, I'm going to 392 00:20:05,200 --> 00:20:08,800 Speaker 1: give you a very legalistic quibble about the definition of 393 00:20:08,800 --> 00:20:11,879 Speaker 1: the word seen. Right, So we have an image of 394 00:20:11,920 --> 00:20:13,600 Speaker 1: a black hole, but does that mean that we have 395 00:20:13,800 --> 00:20:16,840 Speaker 1: seen a black hole? I think if you have an 396 00:20:16,880 --> 00:20:20,080 Speaker 1: image of something that you've captured, then yeah, you've technically 397 00:20:20,119 --> 00:20:21,840 Speaker 1: seen it. I mean, I suppose if you keep the 398 00:20:21,920 --> 00:20:23,960 Speaker 1: lens cap on your camera and you take a picture 399 00:20:23,960 --> 00:20:26,440 Speaker 1: and you have a pure black image, have you taken 400 00:20:26,440 --> 00:20:28,760 Speaker 1: a picture of the inside of your lens cap or 401 00:20:28,800 --> 00:20:30,920 Speaker 1: is it just sort of a non picture? Wait? Wait, wait, 402 00:20:30,960 --> 00:20:34,440 Speaker 1: what of the wait what? Yeah? Technically if I take 403 00:20:34,520 --> 00:20:38,359 Speaker 1: a picture of your inside of your let's cap, is 404 00:20:38,359 --> 00:20:40,120 Speaker 1: that what you're saying? Yeah? I mean the issue here 405 00:20:40,359 --> 00:20:43,640 Speaker 1: is that we don't see any photons from a black hole, 406 00:20:43,760 --> 00:20:46,200 Speaker 1: or in a black hole, if it exists, wouldn't give 407 00:20:46,200 --> 00:20:48,199 Speaker 1: off any light. So the only thing we can do 408 00:20:48,320 --> 00:20:50,320 Speaker 1: is look at the impact of the black hole on 409 00:20:50,560 --> 00:20:54,280 Speaker 1: nearby space and ask is that consistent with what we 410 00:20:54,400 --> 00:20:57,680 Speaker 1: expect from a black hole. That doesn't tell us necessarily 411 00:20:57,720 --> 00:21:00,080 Speaker 1: that the black hole is there. The history of the 412 00:21:00,119 --> 00:21:03,359 Speaker 1: discovery of black hole in the sort of slowly accumulating 413 00:21:03,440 --> 00:21:06,960 Speaker 1: evidence for their existence is all a little bit indirect. 414 00:21:07,080 --> 00:21:09,639 Speaker 1: It's all evidence for what black holes do to the 415 00:21:09,720 --> 00:21:13,000 Speaker 1: stuff near them. I see you're getting a little technical 416 00:21:13,040 --> 00:21:15,920 Speaker 1: here on the definition. But um well, let's maybe step 417 00:21:15,920 --> 00:21:18,520 Speaker 1: people through it. How do we know black holes actually 418 00:21:18,600 --> 00:21:21,960 Speaker 1: sort of exists because we've seen different kinds of evidence 419 00:21:21,960 --> 00:21:24,439 Speaker 1: for them. Right, it dates back to the mid sixties. 420 00:21:24,480 --> 00:21:27,119 Speaker 1: The first evidence we had that suggested the black holes 421 00:21:27,200 --> 00:21:30,119 Speaker 1: might be real were very bright X ray sources. Now, 422 00:21:30,160 --> 00:21:32,600 Speaker 1: remember black holes, they don't emit any light because any 423 00:21:32,680 --> 00:21:35,360 Speaker 1: light that hits them gets absorbed, and they don't give 424 00:21:35,359 --> 00:21:38,080 Speaker 1: off any light because the event horizon. But they're typically 425 00:21:38,119 --> 00:21:42,120 Speaker 1: surrounded by stuff that's very affected by the strong gravity. 426 00:21:42,200 --> 00:21:43,840 Speaker 1: So if you have a bunch of gas and dust 427 00:21:43,880 --> 00:21:46,000 Speaker 1: that's about to fall into the black hole, and the 428 00:21:46,040 --> 00:21:48,480 Speaker 1: intense gravity makes it very very hot, and so it 429 00:21:48,480 --> 00:21:51,080 Speaker 1: emits in the X rays. So in the sixties, people 430 00:21:51,119 --> 00:21:52,920 Speaker 1: saw these X rays from a spot in the sky 431 00:21:53,000 --> 00:21:56,520 Speaker 1: that they didn't see anything else. It's called sidneys X one, 432 00:21:56,680 --> 00:21:58,879 Speaker 1: and they didn't really understand it. And then later people 433 00:21:58,880 --> 00:22:01,639 Speaker 1: were studying a blue super giant which seemed to have 434 00:22:01,800 --> 00:22:04,480 Speaker 1: some heavy object orbiting it that was emitting X rays 435 00:22:04,520 --> 00:22:06,840 Speaker 1: but otherwise totally dark. So these are sort of like 436 00:22:06,880 --> 00:22:09,840 Speaker 1: the first clues that there was something massive with very 437 00:22:09,880 --> 00:22:13,480 Speaker 1: strong gravity that wasn't giving off any light, right, Because 438 00:22:13,480 --> 00:22:16,520 Speaker 1: it's weird for something not to emit regular light, but 439 00:22:16,600 --> 00:22:19,200 Speaker 1: for it to admit X rays, which is also light, 440 00:22:19,240 --> 00:22:21,320 Speaker 1: but it's just light in a different frequency. So it's 441 00:22:21,320 --> 00:22:24,560 Speaker 1: weird for something to emit X rays but not regular light. Right. Yes, 442 00:22:24,600 --> 00:22:28,200 Speaker 1: stuff in the universe emits light based on its temperature. Right. 443 00:22:28,400 --> 00:22:31,200 Speaker 1: As stuff gets hotter, it emits light in higher and 444 00:22:31,280 --> 00:22:34,040 Speaker 1: higher frequencies. So the Sun emits in the visible light 445 00:22:34,040 --> 00:22:36,720 Speaker 1: because of its temperature, the Earth emits in the infrared 446 00:22:36,760 --> 00:22:39,800 Speaker 1: because of its temperature. Very very hot gases out there 447 00:22:39,800 --> 00:22:42,960 Speaker 1: in the universe emit X rays because they're very very hot, 448 00:22:43,000 --> 00:22:45,359 Speaker 1: And so here we have a very compact source of 449 00:22:45,520 --> 00:22:47,720 Speaker 1: X rays, but we don't understand what the object is 450 00:22:47,720 --> 00:22:50,720 Speaker 1: because it's not emitting in any other frequencies, right, And 451 00:22:50,760 --> 00:22:53,360 Speaker 1: so they thought if it's only emitting super duper high 452 00:22:53,400 --> 00:22:56,840 Speaker 1: frequency light, then it must be something extreme, like maybe 453 00:22:56,840 --> 00:22:59,879 Speaker 1: a black hole exactly. And that's also similar to the 454 00:23:00,040 --> 00:23:02,679 Speaker 1: picture that we've seen of a black hole. What is 455 00:23:02,680 --> 00:23:05,000 Speaker 1: that a picture of Well, if you look at it, 456 00:23:05,000 --> 00:23:08,359 Speaker 1: it's a ring of glowing gas and at the center 457 00:23:08,400 --> 00:23:11,679 Speaker 1: it's black. So the part that you're actually seeing is 458 00:23:11,720 --> 00:23:14,800 Speaker 1: the ring of gas around the black hole. It's emitting light, 459 00:23:14,840 --> 00:23:17,800 Speaker 1: it's emitting X rays because it's super duper hot. And 460 00:23:17,800 --> 00:23:20,040 Speaker 1: that's the picture that we've seen. What are we seeing 461 00:23:20,080 --> 00:23:22,720 Speaker 1: from the actual black hole itself? If it's there, What 462 00:23:22,840 --> 00:23:25,560 Speaker 1: we're seeing no photons, it's like you're seeing the inside 463 00:23:25,680 --> 00:23:28,840 Speaker 1: of your camera lens cap right, Right, Well, let's get 464 00:23:28,880 --> 00:23:30,840 Speaker 1: to the picture. But first let's talk about some of 465 00:23:30,880 --> 00:23:32,920 Speaker 1: the other ways we've seen black holes, right, because we 466 00:23:32,960 --> 00:23:35,679 Speaker 1: know they're they're also from their gravity, right exactly. We 467 00:23:35,680 --> 00:23:39,400 Speaker 1: can find places in space where there's very intense gravity 468 00:23:39,560 --> 00:23:41,679 Speaker 1: but no obvious source of it, like the center of 469 00:23:41,680 --> 00:23:43,840 Speaker 1: the Milky Way. When we look at stars in the 470 00:23:43,960 --> 00:23:45,840 Speaker 1: very center of the Milky Way, we see them going 471 00:23:45,920 --> 00:23:48,520 Speaker 1: really really fast and then changing direction on these very 472 00:23:48,600 --> 00:23:51,640 Speaker 1: tight orbits, as if there was a very heavy object 473 00:23:51,800 --> 00:23:53,639 Speaker 1: right there at the center of the Milky Way. And 474 00:23:53,680 --> 00:23:55,639 Speaker 1: folks in nearby U. C. L A. Won the Nobel 475 00:23:55,720 --> 00:23:58,160 Speaker 1: Prize for this discovery last year. They've been tracking these 476 00:23:58,160 --> 00:24:00,960 Speaker 1: stars for like twenty years. Recons directing their orbits, and 477 00:24:00,960 --> 00:24:04,640 Speaker 1: the orbits are consistent with some very massive object at 478 00:24:04,680 --> 00:24:07,560 Speaker 1: the heart of our galaxy, and yet it admits no 479 00:24:07,800 --> 00:24:10,960 Speaker 1: light directly. So that's very suggestive of the existence of 480 00:24:11,000 --> 00:24:13,479 Speaker 1: a black hole. Right, We've all the same black holes 481 00:24:13,520 --> 00:24:17,000 Speaker 1: sort of through gravitational waves, right, Yeah, any object in 482 00:24:17,000 --> 00:24:20,560 Speaker 1: the universe that accelerates is going to give off gravitational waves. 483 00:24:20,840 --> 00:24:22,840 Speaker 1: That just means that everything that has mass has a 484 00:24:22,840 --> 00:24:25,960 Speaker 1: gravitational field, right it pulls on things or bends space 485 00:24:26,000 --> 00:24:29,040 Speaker 1: in a certain way. If that thing now accelerates, then 486 00:24:29,080 --> 00:24:32,080 Speaker 1: that gravitational field changes. Just like if you delete an 487 00:24:32,080 --> 00:24:34,880 Speaker 1: object from space or add an object to space, you're 488 00:24:35,000 --> 00:24:39,399 Speaker 1: changing the gravitational field and that information propagates out through space. 489 00:24:39,760 --> 00:24:42,480 Speaker 1: You don't instantly change the gravitational field of the Sun. 490 00:24:42,520 --> 00:24:44,840 Speaker 1: If you deleted it, the change in the field would 491 00:24:44,840 --> 00:24:48,959 Speaker 1: propagate out through space. So gravitational waves are essentially just 492 00:24:49,280 --> 00:24:53,080 Speaker 1: updates to the gravitational field because something has changed. They 493 00:24:53,119 --> 00:24:55,840 Speaker 1: have a really big, heavy object and you accelerate it. 494 00:24:55,920 --> 00:24:58,879 Speaker 1: For example, if two black holes are orbiting each other 495 00:24:58,920 --> 00:25:01,159 Speaker 1: and then they're falling into awards each other and becoming 496 00:25:01,240 --> 00:25:04,639 Speaker 1: one single massive black hole, then you will see gravitational 497 00:25:04,720 --> 00:25:07,639 Speaker 1: waves from those orbits, and we have seen that, we've 498 00:25:07,680 --> 00:25:10,560 Speaker 1: seen a bunch of those things. What is that actually 499 00:25:10,560 --> 00:25:13,800 Speaker 1: evidence of its evidence that some very dense, massive objects 500 00:25:13,800 --> 00:25:17,199 Speaker 1: were orbiting each other and collapsed into one. Right, So 501 00:25:17,280 --> 00:25:19,159 Speaker 1: it seems like maybe, you know, at the beginning of 502 00:25:19,200 --> 00:25:21,880 Speaker 1: the last century, we came up with this idea more 503 00:25:21,920 --> 00:25:24,280 Speaker 1: officially over a black hole. And over the years we 504 00:25:24,320 --> 00:25:26,960 Speaker 1: saw all this evidence that you know, there are really 505 00:25:27,119 --> 00:25:31,000 Speaker 1: super duper dance things out there in space that are 506 00:25:31,040 --> 00:25:34,520 Speaker 1: not bright, so they're not like stars. They don't seem 507 00:25:34,560 --> 00:25:36,879 Speaker 1: to emit regular light, only X ray, which is the 508 00:25:36,960 --> 00:25:39,760 Speaker 1: super intense kind of light. And so people thought, hey, 509 00:25:39,800 --> 00:25:42,520 Speaker 1: that maybe those those things, those super dense objects are 510 00:25:42,560 --> 00:25:44,840 Speaker 1: black holes. But then actually a few years ago they 511 00:25:44,920 --> 00:25:47,840 Speaker 1: saw they we got pictures of a black hole. But 512 00:25:47,920 --> 00:25:49,440 Speaker 1: now you're telling me that made black holes are not 513 00:25:49,520 --> 00:25:52,880 Speaker 1: black holes. Well, all that evidence is a little bit indirect. 514 00:25:53,000 --> 00:25:56,680 Speaker 1: It supports the conclusion that there's something small, something dark, 515 00:25:56,920 --> 00:26:00,239 Speaker 1: and something heavy, right, but not exactly what it is is. 516 00:26:00,720 --> 00:26:02,919 Speaker 1: And for a long time, the only thing in our 517 00:26:02,960 --> 00:26:06,560 Speaker 1: sort of category of ideas that could be that small, dark, 518 00:26:06,560 --> 00:26:09,680 Speaker 1: and heavy were black holes. So that was evidence that 519 00:26:09,760 --> 00:26:12,280 Speaker 1: black holes exist because we see things out there that 520 00:26:12,320 --> 00:26:15,359 Speaker 1: are consistent with black holes, and there were no other candidates. 521 00:26:15,440 --> 00:26:17,119 Speaker 1: And one thing to keep in mind is sort of 522 00:26:17,160 --> 00:26:20,640 Speaker 1: how close to the black hole our observations come. When 523 00:26:20,640 --> 00:26:23,840 Speaker 1: you think about like stars orbiting the central black hole 524 00:26:23,880 --> 00:26:26,160 Speaker 1: in the Milky Way, they don't ever really get that 525 00:26:26,240 --> 00:26:28,359 Speaker 1: close to the black hole. So yeah, it could be 526 00:26:28,400 --> 00:26:30,480 Speaker 1: a black hole. It could also just be some really 527 00:26:30,560 --> 00:26:33,919 Speaker 1: big dark object not a black hole, because the stars 528 00:26:33,960 --> 00:26:37,159 Speaker 1: don't get close enough to distinguish between those scenarios. So 529 00:26:37,200 --> 00:26:40,000 Speaker 1: what was exciting about the black hole image is that 530 00:26:40,040 --> 00:26:43,359 Speaker 1: now we're looking directly at the gas that's right around 531 00:26:43,440 --> 00:26:45,879 Speaker 1: the black hole, it really shows us sort of how 532 00:26:45,960 --> 00:26:49,160 Speaker 1: small the black hole or whatever this massive object is 533 00:26:49,440 --> 00:26:51,680 Speaker 1: has to be. So again, the black hole image doesn't 534 00:26:51,680 --> 00:26:54,040 Speaker 1: tell us definitively that it is a black hole. It 535 00:26:54,119 --> 00:26:57,000 Speaker 1: just says, well, whatever it is, it's very very small. 536 00:26:57,040 --> 00:27:00,000 Speaker 1: It's smaller than any other picture or any other measure. 537 00:27:00,240 --> 00:27:02,000 Speaker 1: It told us it had to be, right, But I 538 00:27:02,000 --> 00:27:04,480 Speaker 1: feel like the image, you know, it shows an aero 539 00:27:04,600 --> 00:27:07,760 Speaker 1: space out of which no light seems to be escaping, right, 540 00:27:08,440 --> 00:27:11,400 Speaker 1: is something small, something dan, something that not even light 541 00:27:11,400 --> 00:27:13,560 Speaker 1: can escape isn't that the definition of a black hole. 542 00:27:13,560 --> 00:27:16,080 Speaker 1: Wouldn't you just say, look at that giant black dot 543 00:27:16,119 --> 00:27:17,960 Speaker 1: and say, hey, that's a black hole because it's a 544 00:27:18,000 --> 00:27:20,280 Speaker 1: hole and it's black. Well, we don't see any light 545 00:27:20,359 --> 00:27:22,840 Speaker 1: from it, right, but it's not definitive proof that there 546 00:27:22,960 --> 00:27:25,879 Speaker 1: is an actual event horizon there. We don't know that 547 00:27:25,920 --> 00:27:28,400 Speaker 1: there's an event horizon. Well, we talked on the podcast 548 00:27:28,440 --> 00:27:31,399 Speaker 1: once about this other idea of a dark star. Maybe 549 00:27:31,400 --> 00:27:34,359 Speaker 1: black holes don't have an event horizon. But the intense 550 00:27:34,480 --> 00:27:38,879 Speaker 1: gravity of a collapsing star bends space and so it 551 00:27:39,040 --> 00:27:43,040 Speaker 1: like stretches all the light to super long frequencies like 552 00:27:43,440 --> 00:27:47,440 Speaker 1: massively red shifts and everything, and slows down time so 553 00:27:47,480 --> 00:27:49,720 Speaker 1: that it looks like no light is emitted. But the 554 00:27:49,800 --> 00:27:52,320 Speaker 1: light that submitted is just like very low intensity because 555 00:27:52,359 --> 00:27:56,159 Speaker 1: time is slowed, and very long wavelength like the wavelength 556 00:27:56,200 --> 00:27:59,240 Speaker 1: of the galaxy, which makes it impossible to see. We 557 00:27:59,240 --> 00:28:02,720 Speaker 1: couldn't disting whish between those two scenarios. Wait, you're saying 558 00:28:02,720 --> 00:28:04,960 Speaker 1: that maybe there's something there that it could be that 559 00:28:05,440 --> 00:28:08,960 Speaker 1: we're just seeing a black spot that's not trapping light, 560 00:28:09,040 --> 00:28:12,760 Speaker 1: it's just maybe stretching light beyond our sensors. Exactly. We 561 00:28:12,840 --> 00:28:15,200 Speaker 1: don't definitively know that it's an event arise, and we 562 00:28:15,240 --> 00:28:18,240 Speaker 1: haven't been there to test it, to observe it closely 563 00:28:18,320 --> 00:28:20,920 Speaker 1: and directly. We're very very far away from these things, 564 00:28:20,920 --> 00:28:23,520 Speaker 1: and all we're seeing is a lack of photons. But 565 00:28:23,560 --> 00:28:26,840 Speaker 1: there are other ways to explain a lack of photons, right, 566 00:28:26,920 --> 00:28:31,000 Speaker 1: like massive gravitational redshift from an object that doesn't actually 567 00:28:31,119 --> 00:28:34,639 Speaker 1: have an event horizon where it's technically possible for it 568 00:28:34,680 --> 00:28:37,040 Speaker 1: to mat radiation. We wouldn't notice or be able to 569 00:28:37,080 --> 00:28:40,320 Speaker 1: observe that radiation. Right. But isn't it a little suspicious 570 00:28:40,320 --> 00:28:43,000 Speaker 1: that you see this ring of light, right, and then 571 00:28:43,040 --> 00:28:46,360 Speaker 1: it suddenly stops and you just see a black hole? Right? 572 00:28:46,440 --> 00:28:50,240 Speaker 1: Like would something like a star that's collapsing or something 573 00:28:50,240 --> 00:28:53,680 Speaker 1: that's just stretching light. Wouldn't that make it more continuous? Right? 574 00:28:53,720 --> 00:28:55,960 Speaker 1: Because the whole ring is kind of consistent with this 575 00:28:56,040 --> 00:28:58,520 Speaker 1: idea that there's stuff, you know, orbiting around and then 576 00:28:58,600 --> 00:29:01,440 Speaker 1: some of it falls in and then it has to disappear. Otherwise, 577 00:29:01,440 --> 00:29:04,080 Speaker 1: where is it going? Why isn't it shining light? Even 578 00:29:04,120 --> 00:29:07,240 Speaker 1: for a black hole? It's fairly continuous, right, Things get 579 00:29:07,240 --> 00:29:10,320 Speaker 1: gradually redder and redder and more and more slow down 580 00:29:10,320 --> 00:29:12,320 Speaker 1: before they fall in the event horizon. Even for a 581 00:29:12,360 --> 00:29:15,240 Speaker 1: black hole, you never actually see something fall into the 582 00:29:15,280 --> 00:29:18,480 Speaker 1: event horizon, unless, of course, there's something else coming behind 583 00:29:18,520 --> 00:29:20,760 Speaker 1: it to pull the event horizon over it. So these 584 00:29:20,760 --> 00:29:23,600 Speaker 1: scenarios actually look the same, right, having just a very 585 00:29:23,640 --> 00:29:27,920 Speaker 1: intense gravitational source to gradually red shift and slow everything 586 00:29:27,960 --> 00:29:30,400 Speaker 1: down as it falls in, or there being an actual 587 00:29:30,440 --> 00:29:33,880 Speaker 1: event horizon beyond which things can't leave. Those two things 588 00:29:33,960 --> 00:29:37,800 Speaker 1: actually do look the same from a distance. But wouldn't 589 00:29:37,800 --> 00:29:40,760 Speaker 1: people have seen these maybe in the infrared, Like if 590 00:29:40,760 --> 00:29:43,080 Speaker 1: we look out into the center of our galaxy, for example, 591 00:29:43,080 --> 00:29:46,200 Speaker 1: with our infrared telescopes, wouldn't then we see a huge 592 00:29:46,440 --> 00:29:49,160 Speaker 1: source of infrared light. Yeah, but the infrared radiation would 593 00:29:49,160 --> 00:29:52,560 Speaker 1: be crazy long wavelengths. We're talking about like wavelengths the 594 00:29:52,600 --> 00:29:55,440 Speaker 1: size of the galaxy, And we do not have sensors 595 00:29:55,480 --> 00:29:58,320 Speaker 1: that can pick up infrared radiation at those frequencies, right, 596 00:29:58,320 --> 00:29:59,840 Speaker 1: but we don't need We see it sort of ramp 597 00:29:59,880 --> 00:30:02,640 Speaker 1: up towards the infrared spectrum. Yeah, but that would look 598 00:30:02,680 --> 00:30:04,520 Speaker 1: the same for a black hole, right. A black hole 599 00:30:04,560 --> 00:30:07,560 Speaker 1: would also show you more and more infrared as you 600 00:30:07,600 --> 00:30:10,160 Speaker 1: get closer and closer to the event horizon because everything 601 00:30:10,240 --> 00:30:12,400 Speaker 1: is getting red shifted, so they look the same from 602 00:30:12,440 --> 00:30:15,440 Speaker 1: the outside because they have the same gravitational effect on 603 00:30:15,520 --> 00:30:19,200 Speaker 1: things outside the event horizon. What are saying, there's no 604 00:30:19,280 --> 00:30:21,960 Speaker 1: way to tell between a black hole and a not 605 00:30:22,120 --> 00:30:23,960 Speaker 1: black hole. The only way to tell us to go 606 00:30:24,160 --> 00:30:27,000 Speaker 1: visit close up, or to maybe sense things in the 607 00:30:27,160 --> 00:30:30,080 Speaker 1: long infrared. Maybe if you had the ability to sense 608 00:30:30,080 --> 00:30:32,880 Speaker 1: things in the very very far infrared, then something falling 609 00:30:32,920 --> 00:30:36,560 Speaker 1: into a non black hole would continue to emit light 610 00:30:36,720 --> 00:30:39,320 Speaker 1: that you would very faintly see in the very very 611 00:30:39,360 --> 00:30:42,600 Speaker 1: long infrared, whereas things that fall actually past the event 612 00:30:42,640 --> 00:30:45,880 Speaker 1: horizon of a black hole would stop emitting. Although you know, 613 00:30:45,880 --> 00:30:48,480 Speaker 1: if you just drop a single object into a black hole, 614 00:30:48,560 --> 00:30:51,640 Speaker 1: it's going to admit forever because it never actually falls 615 00:30:51,760 --> 00:30:54,160 Speaker 1: past the event horizon, right, So it's really quite tricky. 616 00:30:54,520 --> 00:30:56,880 Speaker 1: M all right, Well, I think what you're saying is 617 00:30:56,880 --> 00:30:59,320 Speaker 1: that there's some doubt about whether even the images that 618 00:30:59,400 --> 00:31:01,360 Speaker 1: we have of a black hole or even a black 619 00:31:01,400 --> 00:31:03,880 Speaker 1: hole or represent the black hole, because there's a very 620 00:31:03,920 --> 00:31:06,920 Speaker 1: technical definition about what counts as a black hole, that 621 00:31:06,920 --> 00:31:09,479 Speaker 1: it's not just a big round circle in space. So 622 00:31:09,520 --> 00:31:11,480 Speaker 1: if it's not a black hole, what could it be. 623 00:31:11,560 --> 00:31:13,280 Speaker 1: So in a previous episode, we did talk about this 624 00:31:13,360 --> 00:31:17,120 Speaker 1: idea of a collapsing star slowed down by a gravity 625 00:31:17,360 --> 00:31:19,360 Speaker 1: that would look just like a black hole, and that's 626 00:31:19,360 --> 00:31:21,280 Speaker 1: a really cool idea. But today we wanted to talk 627 00:31:21,320 --> 00:31:24,200 Speaker 1: about a different idea because there are several ideas for 628 00:31:24,320 --> 00:31:26,440 Speaker 1: what might be there that looks like a black hole 629 00:31:26,480 --> 00:31:28,520 Speaker 1: but actually isn't. The idea here is to sort of 630 00:31:28,520 --> 00:31:31,840 Speaker 1: take a neutron star and extended to a super duper 631 00:31:31,920 --> 00:31:35,960 Speaker 1: neutron star. A fuzzball is like a very very dense 632 00:31:36,120 --> 00:31:39,600 Speaker 1: state of matter where matters condensed even beyond the ability 633 00:31:39,600 --> 00:31:43,400 Speaker 1: of a neutron star, but not quite to a black hole. Right, 634 00:31:43,520 --> 00:31:47,080 Speaker 1: we talked about neutron stars, which are like the densest 635 00:31:47,200 --> 00:31:49,480 Speaker 1: things in the universe, right before you might get to 636 00:31:49,600 --> 00:31:52,280 Speaker 1: a black hole. Maybe recap for us what a neutron 637 00:31:52,320 --> 00:31:54,680 Speaker 1: star is and how they occur. Yeah, so gravity is 638 00:31:54,680 --> 00:31:57,800 Speaker 1: pulling everything together, right, It's gathering gas and dust to 639 00:31:57,880 --> 00:32:00,480 Speaker 1: form stars, and the only way to stop gravity is 640 00:32:00,520 --> 00:32:04,240 Speaker 1: to push back in some way. Our Sun has massive gravity, 641 00:32:04,280 --> 00:32:06,840 Speaker 1: but it doesn't collapse because it's pushing out with its 642 00:32:06,960 --> 00:32:10,240 Speaker 1: nuclear fusion. Creating a lot of energy and radiation pushing back. 643 00:32:10,400 --> 00:32:12,360 Speaker 1: When that ends, though, when the Sun runs out of 644 00:32:12,440 --> 00:32:15,360 Speaker 1: fuel or gets too cool because it's made too many metals, 645 00:32:15,640 --> 00:32:18,120 Speaker 1: then it collapses even further. But there are other ways 646 00:32:18,160 --> 00:32:20,160 Speaker 1: to resist gravity. You can have, for example, a white 647 00:32:20,240 --> 00:32:23,600 Speaker 1: dwarf where matter is compressed really really intensely, but it's 648 00:32:23,640 --> 00:32:26,239 Speaker 1: pushing back because the electrons and the atoms don't like 649 00:32:26,320 --> 00:32:29,400 Speaker 1: to overlap. That can resist gravity. Or you can compress 650 00:32:29,440 --> 00:32:33,280 Speaker 1: it even further so that you squeeze all those electrons 651 00:32:33,360 --> 00:32:36,160 Speaker 1: inside the nucleus where they meet up with protons and 652 00:32:36,240 --> 00:32:39,240 Speaker 1: convert into neutrons. So now you get a very very 653 00:32:39,280 --> 00:32:42,840 Speaker 1: dense object which is essentially just a huge blob of 654 00:32:42,880 --> 00:32:47,040 Speaker 1: neutrons all squeezed together. Right, because neutrons are neutral, so 655 00:32:47,080 --> 00:32:49,320 Speaker 1: I guess they don't repel each other kind of right, 656 00:32:49,360 --> 00:32:51,640 Speaker 1: So they're pretty happy, I guess, to be in that 657 00:32:51,720 --> 00:32:54,280 Speaker 1: super duper dense state. Yeah, though they do feel the 658 00:32:54,320 --> 00:32:57,080 Speaker 1: strong force and the quarks that are inside the neutrons 659 00:32:57,280 --> 00:33:00,000 Speaker 1: push against each other, and so it resists the compress 660 00:33:00,000 --> 00:33:02,400 Speaker 1: shouldn due to gravity, and it wants to stay as 661 00:33:02,400 --> 00:33:04,480 Speaker 1: a neutron. Though we don't know what's going on at 662 00:33:04,480 --> 00:33:07,040 Speaker 1: the very very heart of the neutron stars, where the 663 00:33:07,080 --> 00:33:10,120 Speaker 1: pressure and the density against even crazier we talked about 664 00:33:10,160 --> 00:33:12,840 Speaker 1: in the podcast, it might form weird states of matter 665 00:33:12,920 --> 00:33:16,920 Speaker 1: like cork, gluon plasmas, or nuclear pasta. The point is 666 00:33:16,960 --> 00:33:19,400 Speaker 1: that you still have objects, You still have matters, still 667 00:33:19,400 --> 00:33:24,000 Speaker 1: resisting the compression of gravity. You probably have those fundamental particles, 668 00:33:24,000 --> 00:33:26,640 Speaker 1: the quarks and gluons, swimming around at the heart of 669 00:33:26,640 --> 00:33:29,160 Speaker 1: a neutron star. And that we thought was sort of 670 00:33:29,240 --> 00:33:31,960 Speaker 1: the last defense of matter against gravity. That if you 671 00:33:32,040 --> 00:33:34,960 Speaker 1: made a neutron star heavier more than like maybe two 672 00:33:35,120 --> 00:33:37,120 Speaker 1: or three times the mass of our Sun, that it 673 00:33:37,160 --> 00:33:39,600 Speaker 1: could no longer resist the compression of gravity and it 674 00:33:39,600 --> 00:33:42,320 Speaker 1: would collapse to a black hole. A fuzz ball is saying, wait, 675 00:33:42,480 --> 00:33:46,600 Speaker 1: maybe there's one more like interior fortress. Maybe there's one 676 00:33:46,640 --> 00:33:49,680 Speaker 1: more way to resist that collapse. Maybe the things that 677 00:33:49,680 --> 00:33:53,320 Speaker 1: are inside corks and gluons can do their own thing 678 00:33:53,440 --> 00:33:55,920 Speaker 1: and form a new state of matter to resist gravity. 679 00:33:56,120 --> 00:33:58,960 Speaker 1: M Right, Well, first of all, I guess, can a 680 00:33:59,040 --> 00:34:02,160 Speaker 1: neutron star see what's inside of what we think is 681 00:34:02,160 --> 00:34:05,320 Speaker 1: a black hole? Like can a neutron star trap light 682 00:34:05,720 --> 00:34:07,880 Speaker 1: or at least slow it down enough that it looks 683 00:34:07,880 --> 00:34:11,000 Speaker 1: like a whole. Neutron stars are very dense gravitationally, and 684 00:34:11,040 --> 00:34:13,759 Speaker 1: so they definitely have these kinds of effects on light, 685 00:34:14,160 --> 00:34:17,040 Speaker 1: but they're not massive enough to create a black spot 686 00:34:17,120 --> 00:34:20,200 Speaker 1: in space. We can see neutron stars. We can even 687 00:34:20,239 --> 00:34:23,200 Speaker 1: image X rays from hot spots on their surfaces and 688 00:34:23,280 --> 00:34:26,000 Speaker 1: see them spinning, So we know the neutron stars are there. 689 00:34:26,040 --> 00:34:28,480 Speaker 1: They're hard to spot because they don't go very much 690 00:34:28,480 --> 00:34:30,960 Speaker 1: in the visible but we have seen them. We know 691 00:34:31,040 --> 00:34:32,839 Speaker 1: that they're there, and that they do not have an 692 00:34:32,840 --> 00:34:36,239 Speaker 1: event horizon, not even like a soft event horizon or 693 00:34:36,280 --> 00:34:38,520 Speaker 1: like what sort of looks like to the visible eye 694 00:34:38,560 --> 00:34:41,400 Speaker 1: like an event horizon. But they're also bending light to right, 695 00:34:41,440 --> 00:34:44,000 Speaker 1: and they're also sort of, if not trapping, then slowing 696 00:34:44,080 --> 00:34:47,000 Speaker 1: light down enough so that it looks black to us. 697 00:34:47,200 --> 00:34:50,920 Speaker 1: They're definitely slowing down time, and they're definitely red shifting 698 00:34:51,040 --> 00:34:53,239 Speaker 1: light because of their gravity, but they do not have 699 00:34:53,280 --> 00:34:56,280 Speaker 1: an event horizon. We can see emissions directly from neutron 700 00:34:56,360 --> 00:34:59,600 Speaker 1: stars absolutely, all right. So then inside of an image 701 00:34:59,600 --> 00:35:01,359 Speaker 1: of the black hole, it's definitely not a neutron star. 702 00:35:01,440 --> 00:35:04,120 Speaker 1: So you're saying, maybe a neutron star. There's a one 703 00:35:04,680 --> 00:35:07,360 Speaker 1: thing it can turn into that would look like a 704 00:35:07,360 --> 00:35:09,600 Speaker 1: black hole, but that is not a black hole. Exactly. 705 00:35:09,640 --> 00:35:12,000 Speaker 1: As you add more mass to a neutron star, then 706 00:35:12,000 --> 00:35:15,360 Speaker 1: the gravity gets stronger and stronger, maybe so strong that 707 00:35:15,440 --> 00:35:18,680 Speaker 1: the corks and gluons now crack open. Our experiments can't 708 00:35:18,719 --> 00:35:21,120 Speaker 1: see what's inside quarks and gluons. We don't know if 709 00:35:21,160 --> 00:35:23,440 Speaker 1: there is anything inside them at all, and if that 710 00:35:23,640 --> 00:35:26,480 Speaker 1: is what it is. We have several candidate theories, but 711 00:35:26,600 --> 00:35:29,920 Speaker 1: it's all basically just mathematical speculation. We know corks and 712 00:35:29,920 --> 00:35:32,719 Speaker 1: gluons are real, we don't know what's inside them. But 713 00:35:33,520 --> 00:35:36,000 Speaker 1: if corks and gluons are made out of these things 714 00:35:36,040 --> 00:35:39,239 Speaker 1: called strings, out of string theory, that it might be 715 00:35:39,280 --> 00:35:42,480 Speaker 1: possible when you make that neutron star more massive than 716 00:35:42,520 --> 00:35:44,520 Speaker 1: instead of collapsing all the way to a black hole, 717 00:35:44,719 --> 00:35:47,640 Speaker 1: that those strings come out of the corks and gluons 718 00:35:47,719 --> 00:35:50,600 Speaker 1: and do their own weird dance to create this bizarre 719 00:35:50,680 --> 00:35:54,120 Speaker 1: object called a fuzz ball, which would be capable of 720 00:35:54,160 --> 00:35:57,759 Speaker 1: resisting gravitational collapse. M I see. So like if you 721 00:35:57,800 --> 00:36:00,280 Speaker 1: take a neutron star add more mass to it, into 722 00:36:00,320 --> 00:36:03,480 Speaker 1: the gravity is so great it cracks open the corks 723 00:36:03,520 --> 00:36:06,359 Speaker 1: and the strong force that's holding them together and sort 724 00:36:06,400 --> 00:36:09,719 Speaker 1: of apart. And once you crack those open, maybe there 725 00:36:09,719 --> 00:36:13,279 Speaker 1: are strings that then stay whole. They don't collapse into 726 00:36:13,320 --> 00:36:16,280 Speaker 1: a black hole because there might be some string force. 727 00:36:16,360 --> 00:36:18,759 Speaker 1: I guess it's keeping them from collapsing into a black hole. 728 00:36:18,840 --> 00:36:22,120 Speaker 1: Exactly is there is something inside corks and gluons and 729 00:36:22,160 --> 00:36:24,600 Speaker 1: it's held together with some force we don't know yet, 730 00:36:24,800 --> 00:36:26,800 Speaker 1: Not the strong force that's the one that holds corks 731 00:36:26,800 --> 00:36:29,760 Speaker 1: and gluons together to each other. But whatever is inside 732 00:36:29,840 --> 00:36:32,680 Speaker 1: corks and gluons is being held together with some other 733 00:36:32,760 --> 00:36:35,320 Speaker 1: force we haven't yet discovered. The string force, not the 734 00:36:35,400 --> 00:36:38,359 Speaker 1: strong force, the string force. What's stronger the string force 735 00:36:38,440 --> 00:36:40,600 Speaker 1: or the strong force? What stringing here? The string force 736 00:36:40,680 --> 00:36:43,319 Speaker 1: or the strong force. It's a mess. Maybe it's the 737 00:36:43,320 --> 00:36:45,640 Speaker 1: strange force. Maybe to pick another vowel, you know, the 738 00:36:45,680 --> 00:36:49,520 Speaker 1: string force stirm and dring, the strong force, the strong 739 00:36:50,080 --> 00:36:54,640 Speaker 1: strong force. There you go, Well, whatever is inside corks 740 00:36:54,640 --> 00:36:56,680 Speaker 1: and gluons, if there is something inside there would have 741 00:36:56,719 --> 00:36:59,520 Speaker 1: some force and you have to overcome that to crack 742 00:36:59,560 --> 00:37:02,000 Speaker 1: it open. And yeah, maybe those would be strings, and 743 00:37:02,000 --> 00:37:04,759 Speaker 1: those strings interact in ways that we don't even really 744 00:37:04,800 --> 00:37:08,399 Speaker 1: fully understand because string theory math is very very hard 745 00:37:08,480 --> 00:37:11,000 Speaker 1: to do, very complicated. But the idea is that if 746 00:37:11,000 --> 00:37:13,920 Speaker 1: you squeeze a bunch of these strings close enough together, 747 00:37:14,239 --> 00:37:17,239 Speaker 1: then they might tie themselves into these really weird, very 748 00:37:17,320 --> 00:37:21,280 Speaker 1: very long strings. Like strings. We think, if they do exist, 749 00:37:21,640 --> 00:37:23,759 Speaker 1: that they're super duper small. They're like ten to the 750 00:37:23,880 --> 00:37:27,920 Speaker 1: minus thirty five meters wide distance we call the plank length. 751 00:37:28,080 --> 00:37:29,520 Speaker 1: But if you take a bunch of strings and you 752 00:37:29,520 --> 00:37:32,040 Speaker 1: squeeze them together, we think they might loop up and 753 00:37:32,080 --> 00:37:36,040 Speaker 1: form super duper big strings. Like as you squeeze them together, 754 00:37:36,120 --> 00:37:40,319 Speaker 1: weirdly they get larger, right, like real string. Well, let's 755 00:37:40,320 --> 00:37:42,799 Speaker 1: get into the details here of a string hoole. I 756 00:37:42,800 --> 00:37:44,640 Speaker 1: guess you would have to change the name of it, right, 757 00:37:44,719 --> 00:37:46,400 Speaker 1: Maybe fause ball is not the right name. Maybe it 758 00:37:46,400 --> 00:37:48,360 Speaker 1: should be a string ball. So let's get into the 759 00:37:48,360 --> 00:37:50,759 Speaker 1: details of that and whether or not we might ever 760 00:37:50,880 --> 00:37:53,759 Speaker 1: be able to detect such a thing in space. But 761 00:37:53,800 --> 00:38:08,239 Speaker 1: first let's take another quick break. I feel like you're 762 00:38:08,239 --> 00:38:11,319 Speaker 1: stringing me along here, Daniel, to answer the question whether 763 00:38:11,400 --> 00:38:13,960 Speaker 1: or not the black hole really exists or is what 764 00:38:14,000 --> 00:38:16,359 Speaker 1: we think a black hole? What we think is an 765 00:38:16,400 --> 00:38:18,400 Speaker 1: image of a black hole is actually an image of 766 00:38:18,480 --> 00:38:21,440 Speaker 1: something else that is technically not a black hole, but 767 00:38:21,520 --> 00:38:25,840 Speaker 1: maybe something called a string ball. Well, the Adventures of 768 00:38:25,880 --> 00:38:27,640 Speaker 1: It could have called it a string ball, but they 769 00:38:27,680 --> 00:38:30,279 Speaker 1: decided to go with a fuzz ball instead, right, even 770 00:38:30,320 --> 00:38:32,680 Speaker 1: though string ball would be more accurate, wouldn't it. I 771 00:38:32,680 --> 00:38:35,680 Speaker 1: don't know the images I've seen online that describe what 772 00:38:35,719 --> 00:38:38,440 Speaker 1: these scientists are thinking about. It looks pretty fuzzy, so 773 00:38:38,560 --> 00:38:40,360 Speaker 1: you know, I like buzz ball. Well, I think the 774 00:38:40,400 --> 00:38:42,719 Speaker 1: idea is that if you take a neutron star, which 775 00:38:42,760 --> 00:38:46,000 Speaker 1: is a super duper heavy object, and then you squeeze 776 00:38:46,000 --> 00:38:48,960 Speaker 1: it even more, you break open the neutrons and the corks, 777 00:38:49,360 --> 00:38:51,520 Speaker 1: and you spill out all the strings that might be 778 00:38:51,600 --> 00:38:54,200 Speaker 1: inside of a cork, and then you make a ball 779 00:38:54,200 --> 00:38:58,520 Speaker 1: out of those things before they actually collapse into an 780 00:38:58,560 --> 00:39:02,120 Speaker 1: infinite singularity, which is but would be a black hole exactly, 781 00:39:02,200 --> 00:39:06,120 Speaker 1: these things would resist collapse because of their stringiness. And also, 782 00:39:06,200 --> 00:39:10,759 Speaker 1: really interestingly, strings themselves can't be part of a singularity 783 00:39:10,800 --> 00:39:13,800 Speaker 1: because they have an extent, right, they have a minimum size. 784 00:39:14,400 --> 00:39:17,759 Speaker 1: Strings are not point objects the way electrons are or 785 00:39:17,840 --> 00:39:20,640 Speaker 1: quarks are in our current theory or in any theory 786 00:39:20,680 --> 00:39:24,239 Speaker 1: of fundamental particles. Strings themselves have a minimum size there 787 00:39:24,239 --> 00:39:27,280 Speaker 1: are quantum object so they can never have infinite density, 788 00:39:27,360 --> 00:39:28,799 Speaker 1: which is sort of cool. Even if you had a 789 00:39:28,840 --> 00:39:31,840 Speaker 1: single string, right, it's not a singularity. And here you 790 00:39:31,880 --> 00:39:34,040 Speaker 1: take a bunch of strings, you put them together into 791 00:39:34,080 --> 00:39:36,160 Speaker 1: a string ball or a buzz ball, whatever you want 792 00:39:36,160 --> 00:39:38,960 Speaker 1: to call it, and it's actually quite big and quite massive. 793 00:39:39,480 --> 00:39:42,319 Speaker 1: So this thing would be like a huge object. But 794 00:39:42,400 --> 00:39:46,680 Speaker 1: it's also like made out of this weird fundamentally quantum 795 00:39:46,719 --> 00:39:48,960 Speaker 1: thing a string. So you know, the sort of the 796 00:39:49,000 --> 00:39:52,759 Speaker 1: way like a Bose Einstein condensate is a macroscopic object 797 00:39:52,800 --> 00:39:55,840 Speaker 1: that obeys quantum properties. This thing also would be like 798 00:39:55,880 --> 00:40:00,800 Speaker 1: a really big, huge macroscopic object that shows it's stringing nature. 799 00:40:01,160 --> 00:40:03,480 Speaker 1: M So it'd be made out of strings. And you 800 00:40:03,480 --> 00:40:06,480 Speaker 1: said that the strings would tie themselves together or you know, 801 00:40:06,560 --> 00:40:09,680 Speaker 1: sort of become longer strands of strings. Strings when you 802 00:40:09,719 --> 00:40:13,920 Speaker 1: combine them, their tension actually decreases, right, So as you 803 00:40:13,960 --> 00:40:17,439 Speaker 1: put more strings together, the tension decreases as they get 804 00:40:17,480 --> 00:40:20,480 Speaker 1: longer and longer. So are similar to like a guitar string, right, 805 00:40:20,640 --> 00:40:23,640 Speaker 1: A guitar string that you shorten has a higher tension 806 00:40:23,680 --> 00:40:26,040 Speaker 1: and makes a higher sound, whereas if you let your 807 00:40:26,040 --> 00:40:28,880 Speaker 1: guitar string get longer than it makes a deeper sound. Right, 808 00:40:28,880 --> 00:40:30,440 Speaker 1: And that's how it works on the fretboard, right, you're 809 00:40:30,480 --> 00:40:32,960 Speaker 1: shortening the length of the string, you're increasing the tension, 810 00:40:33,160 --> 00:40:35,839 Speaker 1: so you're increasing the frequency. The same thing happens for 811 00:40:35,920 --> 00:40:38,000 Speaker 1: these kinds of strings. As you tie a bunch of 812 00:40:38,040 --> 00:40:41,000 Speaker 1: them together, they tend to get longer and the tension decreases. 813 00:40:41,080 --> 00:40:43,080 Speaker 1: And so if you can squeeze a bunch of strings together, 814 00:40:43,120 --> 00:40:47,239 Speaker 1: they can make really big macroscopic objects like a fuzzball, 815 00:40:47,640 --> 00:40:50,200 Speaker 1: sort of like a new state of matter. You can 816 00:40:50,239 --> 00:40:53,080 Speaker 1: imagine it as all right, So then I guess you 817 00:40:53,120 --> 00:40:56,399 Speaker 1: can compact all that mass even more, so you get 818 00:40:56,440 --> 00:40:59,640 Speaker 1: even more intense density and even more bending at space. 819 00:40:59,719 --> 00:41:02,880 Speaker 1: Would you then be able to trap light? Yeah, fuzzball 820 00:41:03,000 --> 00:41:06,080 Speaker 1: has so much gravity in such a tiny spot that 821 00:41:06,200 --> 00:41:09,799 Speaker 1: from the outside it looks like a black hole, right, 822 00:41:09,800 --> 00:41:12,400 Speaker 1: the same way a dark star does. You don't actually 823 00:41:12,400 --> 00:41:15,280 Speaker 1: have to have a singularity in order to bend space 824 00:41:15,480 --> 00:41:20,400 Speaker 1: enough to create gravitational redshifting and time dilation to look 825 00:41:20,480 --> 00:41:23,080 Speaker 1: like a black hole, or to be indistinguishable with our 826 00:41:23,120 --> 00:41:26,799 Speaker 1: technology from a true general relativistic black hole, so it 827 00:41:26,840 --> 00:41:30,400 Speaker 1: would have an event horizon. It doesn't have an event horizon, right, 828 00:41:30,600 --> 00:41:32,759 Speaker 1: like a black hole, there is no event horizon there. 829 00:41:32,840 --> 00:41:34,840 Speaker 1: But it does distort light in the same way a 830 00:41:34,960 --> 00:41:38,319 Speaker 1: dark star wood. It makes the frequencies very very long, 831 00:41:38,480 --> 00:41:42,080 Speaker 1: very red, and it slows everything down. Wait, why wouldn't 832 00:41:42,080 --> 00:41:44,759 Speaker 1: it have an event horizon. Couldn't you imagine putting so 833 00:41:44,760 --> 00:41:47,440 Speaker 1: many strengths in one spot that it would create an 834 00:41:47,480 --> 00:41:50,520 Speaker 1: event horizon. You could, But this thing resists collapse to 835 00:41:50,600 --> 00:41:53,000 Speaker 1: that density because the strings have the sort of like 836 00:41:53,040 --> 00:41:57,000 Speaker 1: outward pressure like puff up, providing enough outward pressure to 837 00:41:57,000 --> 00:42:00,279 Speaker 1: avoid collapsing to that density. But that's only as ming 838 00:42:00,360 --> 00:42:03,280 Speaker 1: SEMs that the force that keeps them together is strong 839 00:42:03,400 --> 00:42:06,600 Speaker 1: enough to prevent the event horizon from forming. But couldn't 840 00:42:06,640 --> 00:42:09,040 Speaker 1: you also imagine a string ball where the force is 841 00:42:09,080 --> 00:42:12,160 Speaker 1: strong enough not to create a singularity, but maybe strong 842 00:42:12,280 --> 00:42:14,440 Speaker 1: enough to create an event horizon. In principle, what you're 843 00:42:14,440 --> 00:42:17,000 Speaker 1: describing is like a quantum mechanical black hole, where you 844 00:42:17,000 --> 00:42:19,719 Speaker 1: have enough mass within like the short styles radius to 845 00:42:19,960 --> 00:42:23,000 Speaker 1: create an event horizon. That is technically possible if you 846 00:42:23,000 --> 00:42:25,640 Speaker 1: can get some matter to that density This is the 847 00:42:25,719 --> 00:42:29,080 Speaker 1: suggestion that strings are preventing the matter from getting to 848 00:42:29,200 --> 00:42:32,359 Speaker 1: that density, so there is no event horizon there. You're 849 00:42:32,440 --> 00:42:35,040 Speaker 1: right that if in principle, you could squeeze the strings 850 00:42:35,040 --> 00:42:38,200 Speaker 1: down even further, you could satisfy that condition and create 851 00:42:38,200 --> 00:42:41,120 Speaker 1: a classical black hole. But the calculations here suggest as 852 00:42:41,160 --> 00:42:44,879 Speaker 1: strings are puffy enough that they resist compression, so they 853 00:42:44,920 --> 00:42:47,279 Speaker 1: don't actually form a black hole. That's what makes this 854 00:42:47,360 --> 00:42:50,080 Speaker 1: different from a black hole. There's no event horizon here, 855 00:42:50,600 --> 00:42:52,799 Speaker 1: right right, We're not asking the question like how can 856 00:42:52,840 --> 00:42:55,279 Speaker 1: you make a black hole without a singularity. We're asking 857 00:42:55,320 --> 00:42:57,560 Speaker 1: the question, can you create something that looks like a 858 00:42:57,600 --> 00:43:00,000 Speaker 1: black hole that wouldn't turn into a black hole? Exactly? 859 00:43:00,160 --> 00:43:03,960 Speaker 1: Is there another step between neutron star and actual density 860 00:43:03,960 --> 00:43:06,640 Speaker 1: of objects that create an event horizon? And this suggestion 861 00:43:06,680 --> 00:43:09,040 Speaker 1: from string theory is that you can form this new 862 00:43:09,080 --> 00:43:11,799 Speaker 1: state of matter called a fuzzball, which is not dense 863 00:43:11,920 --> 00:43:14,120 Speaker 1: enough to create an event horizon, but sort of looks 864 00:43:14,160 --> 00:43:17,560 Speaker 1: a lot like an event horizon to our technological eyeballs. 865 00:43:17,920 --> 00:43:20,640 Speaker 1: Right because before the only step we knew was a 866 00:43:20,680 --> 00:43:22,920 Speaker 1: neutron star, and we know that a neutron star wouldn't 867 00:43:22,920 --> 00:43:25,400 Speaker 1: look like a black hole. But maybe because we know 868 00:43:25,640 --> 00:43:28,120 Speaker 1: enough about the strong force, I guess to make that call. 869 00:43:28,280 --> 00:43:31,040 Speaker 1: But maybe there's something that neutron star would collapse to 870 00:43:31,200 --> 00:43:33,560 Speaker 1: that wouldn't be a true black hole. Yeah, exactly, you 871 00:43:33,600 --> 00:43:36,000 Speaker 1: add mass to a neutron star, maybe there's another step 872 00:43:36,040 --> 00:43:38,560 Speaker 1: there before it collapses to the density you need to 873 00:43:38,600 --> 00:43:41,440 Speaker 1: create an event horizon. But from a distance, this thing 874 00:43:41,520 --> 00:43:43,719 Speaker 1: is so close to an official black hole in terms 875 00:43:43,719 --> 00:43:47,080 Speaker 1: of density that it acts almost like one. It's indistinguishable 876 00:43:47,160 --> 00:43:49,600 Speaker 1: using our sensors from an actual black hole with the 877 00:43:49,640 --> 00:43:52,040 Speaker 1: real event horizon, right, would be more like a black 878 00:43:52,120 --> 00:43:54,279 Speaker 1: divid like vivid sort of looks like a hole from 879 00:43:54,280 --> 00:43:58,560 Speaker 1: a certain press practice because there is it's trapping some things, 880 00:43:58,719 --> 00:44:00,719 Speaker 1: but it's not actually a whole. Yeah, or maybe it's 881 00:44:00,719 --> 00:44:04,239 Speaker 1: like an off black hole. Right, it's not black. If 882 00:44:04,280 --> 00:44:07,040 Speaker 1: you look at really really carefully with the right instrument, 883 00:44:07,080 --> 00:44:10,080 Speaker 1: you might detect some radiation, right, Yeah, But I think 884 00:44:10,080 --> 00:44:12,120 Speaker 1: what it would sort of pretty much act like a 885 00:44:12,160 --> 00:44:13,879 Speaker 1: black hole, like if you get near it, it would 886 00:44:13,920 --> 00:44:17,960 Speaker 1: spaghettify you perhaps, right. Absolutely, gravity from a distance is 887 00:44:18,000 --> 00:44:20,440 Speaker 1: the same as from any object of that mass, And 888 00:44:20,480 --> 00:44:22,960 Speaker 1: because it is really really dense, you could get close 889 00:44:23,040 --> 00:44:25,839 Speaker 1: enough for the tidal forces to be very dramatic. Right, 890 00:44:25,880 --> 00:44:28,960 Speaker 1: And it would also form the rings around itself. Right, Yeah, 891 00:44:29,000 --> 00:44:31,400 Speaker 1: it would form an acretion disk exactly. Just that. The 892 00:44:31,400 --> 00:44:33,960 Speaker 1: difference is that it doesn't create an event horizon exactly. 893 00:44:33,960 --> 00:44:36,719 Speaker 1: That's the difference. And it's not just speculation. These guys 894 00:44:36,719 --> 00:44:39,640 Speaker 1: have done these calculations in string theory and suggested that 895 00:44:39,719 --> 00:44:42,640 Speaker 1: this thing could actually form. That's really as possible for 896 00:44:42,680 --> 00:44:45,399 Speaker 1: strings to create this state of matter. It's not just like, hey, 897 00:44:45,480 --> 00:44:48,120 Speaker 1: maybe there's some state of matter. It actually does come 898 00:44:48,160 --> 00:44:51,120 Speaker 1: from the calculations of how we think strings would behave 899 00:44:51,360 --> 00:44:54,120 Speaker 1: if they were real. Right. But strength theories totally made up, 900 00:44:54,160 --> 00:44:58,080 Speaker 1: so you know, it's the same thing. And if you 901 00:44:58,120 --> 00:45:00,400 Speaker 1: make something up, if you prove something with a made theory, 902 00:45:00,680 --> 00:45:02,680 Speaker 1: it's still made up, isn't it. It is still made 903 00:45:02,760 --> 00:45:04,840 Speaker 1: up in this case, though it does match everything we 904 00:45:04,880 --> 00:45:07,160 Speaker 1: see in the universe. Right. They basically give the same 905 00:45:07,200 --> 00:45:11,439 Speaker 1: predictions for the observations as the classical general relativistic black hole. 906 00:45:11,640 --> 00:45:14,600 Speaker 1: And it solves the quantum mechanics problem because these things 907 00:45:14,640 --> 00:45:18,160 Speaker 1: do not create singularities that violate quantum mechanics. They are 908 00:45:18,200 --> 00:45:21,160 Speaker 1: actual quantum mechanical objects. Plus they solve a bunch of 909 00:45:21,200 --> 00:45:24,600 Speaker 1: other problems related to black holes, so theoretically they are 910 00:45:24,719 --> 00:45:27,640 Speaker 1: very attractive for those reasons. Although you're right, we can't 911 00:45:27,640 --> 00:45:30,280 Speaker 1: tell the difference between a black hole and a string 912 00:45:30,280 --> 00:45:33,200 Speaker 1: ball or a fuzz ball, and so from that sense, 913 00:45:33,280 --> 00:45:35,560 Speaker 1: it is just still made up, right. And also you've 914 00:45:35,560 --> 00:45:37,319 Speaker 1: got to ask the question, like what happens if you 915 00:45:37,360 --> 00:45:39,400 Speaker 1: do have a string ball and you put more strings 916 00:45:39,400 --> 00:45:41,440 Speaker 1: into it? Is it eventually going to collapse into a 917 00:45:41,440 --> 00:45:43,759 Speaker 1: black hole? Or are they saying that string balls can 918 00:45:43,800 --> 00:45:46,800 Speaker 1: never become black holes? These would never become black holes 919 00:45:46,840 --> 00:45:49,920 Speaker 1: because as you add more strings, they get larger and larger, 920 00:45:50,160 --> 00:45:52,800 Speaker 1: so they don't get denser. Tension on the strings actually 921 00:45:52,800 --> 00:45:56,000 Speaker 1: get smaller as they get larger. So as you add 922 00:45:56,040 --> 00:45:58,560 Speaker 1: more and more strings, you just get a bigger string ball. 923 00:45:59,000 --> 00:46:01,840 Speaker 1: M hm. So you ever increase the density, that's what 924 00:46:01,880 --> 00:46:04,600 Speaker 1: you're saying. Yeah, the density never crosses that threshold. But 925 00:46:04,640 --> 00:46:07,320 Speaker 1: if the force relaxes, wouldn't you be able to compress 926 00:46:07,400 --> 00:46:09,560 Speaker 1: them more more stuff? You mean, like the force just 927 00:46:09,560 --> 00:46:11,960 Speaker 1: took a vacation. It's like, hey, it's Friday, I'm tired 928 00:46:12,040 --> 00:46:14,960 Speaker 1: of holding the string ball up yeah, pasically right, Like, 929 00:46:15,000 --> 00:46:17,800 Speaker 1: if he's saying that the strings get more relaxed, wouldn't 930 00:46:17,840 --> 00:46:20,279 Speaker 1: you be able to slip in more smaller strings in there? 931 00:46:20,480 --> 00:46:23,279 Speaker 1: The strings getting more relaxed means length goes up, right, 932 00:46:23,280 --> 00:46:26,160 Speaker 1: because the tension and the length are inversely proportional. That's 933 00:46:26,160 --> 00:46:28,480 Speaker 1: why these things get bigger and bigger. So maybe in 934 00:46:28,520 --> 00:46:31,080 Speaker 1: some versions of string theory these things wouldn't be allowed. 935 00:46:31,200 --> 00:46:34,319 Speaker 1: But in the calculations that these folks have done, they 936 00:46:34,320 --> 00:46:37,280 Speaker 1: suggested these things would never collapse to have an object 937 00:46:37,280 --> 00:46:40,319 Speaker 1: with an event horizon. All right, So then this is 938 00:46:40,320 --> 00:46:43,160 Speaker 1: an idea that maybe says that the things that we 939 00:46:43,200 --> 00:46:45,480 Speaker 1: think are black holes are actually not black holes. Although 940 00:46:45,640 --> 00:46:48,160 Speaker 1: even if these things do exist, would that make black 941 00:46:48,160 --> 00:46:52,000 Speaker 1: holes impossible or just not likely? These would make black 942 00:46:52,040 --> 00:46:54,879 Speaker 1: holes impossible at least out of matter that is made 943 00:46:54,880 --> 00:46:57,680 Speaker 1: of strings. Couldn't I smash two strings together, a bunch 944 00:46:57,680 --> 00:47:00,200 Speaker 1: of strings together, so fast and so hard that they 945 00:47:00,320 --> 00:47:02,680 Speaker 1: form a real black hole. You know, that's a great 946 00:47:02,760 --> 00:47:07,080 Speaker 1: question if temporarily you could overcome this stringy puffinus to 947 00:47:07,200 --> 00:47:09,319 Speaker 1: create that density. I don't know the answer to that, 948 00:47:09,360 --> 00:47:11,440 Speaker 1: and I don't know if anybody does, Because you know, 949 00:47:11,480 --> 00:47:14,399 Speaker 1: these calculations are very very hard to do. String theory 950 00:47:14,520 --> 00:47:17,200 Speaker 1: is very complex. These calculations are done in like eleven 951 00:47:17,280 --> 00:47:20,280 Speaker 1: or twenty six dimensions because that's the space in which 952 00:47:20,320 --> 00:47:22,600 Speaker 1: strings work. And so I don't think anybody knows the 953 00:47:22,640 --> 00:47:25,280 Speaker 1: answer what would happen if you collided to string balls? 954 00:47:25,440 --> 00:47:28,880 Speaker 1: Let's do it. But I feel like it's convenient that 955 00:47:29,280 --> 00:47:32,279 Speaker 1: made up theory is so complex you can actually do 956 00:47:32,360 --> 00:47:34,200 Speaker 1: a lot of calculations in it. You know, the people 957 00:47:34,239 --> 00:47:36,880 Speaker 1: who do string theories say it's beautiful and it's wonderful. 958 00:47:37,000 --> 00:47:39,400 Speaker 1: I've never done any string theory calculations myself, so I 959 00:47:39,400 --> 00:47:41,680 Speaker 1: can't attest to that. But it is very complicated, as 960 00:47:41,680 --> 00:47:43,319 Speaker 1: only a few people in the world who know how 961 00:47:43,360 --> 00:47:46,400 Speaker 1: to do string theory calculations. And also we should say 962 00:47:46,440 --> 00:47:49,239 Speaker 1: that they haven't done the full calculation here. They've taken 963 00:47:49,400 --> 00:47:51,560 Speaker 1: like a lot of simplifications and they've solved it in 964 00:47:51,680 --> 00:47:55,160 Speaker 1: like a few different cases that are related to our universe, 965 00:47:55,200 --> 00:47:59,399 Speaker 1: but not exactly our universe. So they sort of suggestive calculations, 966 00:47:59,440 --> 00:48:03,319 Speaker 1: not like really conclusive results. Interesting, well, we might need 967 00:48:03,360 --> 00:48:06,000 Speaker 1: to change the name of black holes to spring balls 968 00:48:06,600 --> 00:48:10,120 Speaker 1: or or fuzzballs, and this is also convenient like this 969 00:48:10,200 --> 00:48:12,400 Speaker 1: idea of a fuzz ball or a string ball is 970 00:48:12,440 --> 00:48:16,640 Speaker 1: interesting too because you said it solves other inconsistencies about 971 00:48:16,680 --> 00:48:19,560 Speaker 1: real black holes. Classical black holes, the ones imagined by 972 00:48:19,600 --> 00:48:22,600 Speaker 1: Einstein's theory of relativity, have a lot of problems with 973 00:48:22,680 --> 00:48:25,480 Speaker 1: quantum mechanics, but they also have problems with information. You know. 974 00:48:25,560 --> 00:48:28,720 Speaker 1: One problem is that things are falling into the black hole, 975 00:48:29,120 --> 00:48:31,399 Speaker 1: and a classical black hole just sort of eats them. 976 00:48:31,440 --> 00:48:34,080 Speaker 1: But we know that black holes eventually will evaporate. They 977 00:48:34,080 --> 00:48:37,960 Speaker 1: admit this faint radiation at their edges called Hawking radiation, 978 00:48:38,080 --> 00:48:40,880 Speaker 1: and so they disappear, and so in our universe that 979 00:48:40,960 --> 00:48:43,200 Speaker 1: means that the information falls into a black hole and 980 00:48:43,239 --> 00:48:45,279 Speaker 1: then is gone. We had a fun episode about the 981 00:48:45,280 --> 00:48:48,000 Speaker 1: black hole information paradox, so check that out. But this 982 00:48:48,040 --> 00:48:49,920 Speaker 1: is a real problem with the sort of the structure 983 00:48:50,040 --> 00:48:53,840 Speaker 1: of classical black holes. What happens to information that falls 984 00:48:53,920 --> 00:48:56,560 Speaker 1: inside of them? And so this solves them because there 985 00:48:56,640 --> 00:48:59,239 Speaker 1: is no event horizon, and so nothing falls past the 986 00:48:59,280 --> 00:49:02,960 Speaker 1: event horizon and disappears. So it sort of solves that 987 00:49:02,960 --> 00:49:05,839 Speaker 1: problem by deleting it from the universe. M I see, 988 00:49:05,880 --> 00:49:08,520 Speaker 1: if there is no event horizon, then there's no problem 989 00:49:08,640 --> 00:49:11,360 Speaker 1: with an event horizon. Basically, stuff that you throw into 990 00:49:11,360 --> 00:49:13,960 Speaker 1: the string ball just becomes more strings, and this quantum 991 00:49:13,960 --> 00:49:17,160 Speaker 1: information is not lost, is still there on the string ball, 992 00:49:17,640 --> 00:49:19,800 Speaker 1: all right, And that would make more sense in the universe, 993 00:49:20,080 --> 00:49:24,160 Speaker 1: or it would just be more more easier to study, 994 00:49:24,360 --> 00:49:27,120 Speaker 1: that would make more sense. Quantum mechanics says that information 995 00:49:27,160 --> 00:49:30,880 Speaker 1: cannot be lost, that everything you do imprints itself on 996 00:49:30,960 --> 00:49:33,960 Speaker 1: the future of the universe, and then in principle, you 997 00:49:34,000 --> 00:49:36,719 Speaker 1: could reverse engineering to find out exactly what happened in 998 00:49:36,760 --> 00:49:39,880 Speaker 1: the past. It's very deep principle in quantum mechanics. And 999 00:49:39,880 --> 00:49:41,640 Speaker 1: if that is wrong, then like everything we think we 1000 00:49:41,719 --> 00:49:44,719 Speaker 1: understood abou quantum mechanics is wrong. So according to our 1001 00:49:44,719 --> 00:49:47,200 Speaker 1: current theories, information should not be lost in the universe, 1002 00:49:47,280 --> 00:49:50,000 Speaker 1: and yet classical black holes do seem to delete it. 1003 00:49:50,320 --> 00:49:53,120 Speaker 1: So this would nicely avert that problem, all right. Well, 1004 00:49:53,239 --> 00:49:55,680 Speaker 1: it sounds like every time you look at an image 1005 00:49:55,680 --> 00:49:57,239 Speaker 1: of a black hole, you should, in the back of 1006 00:49:57,280 --> 00:50:00,400 Speaker 1: your mind think, maybe it's not a black hole, maybe 1007 00:50:00,400 --> 00:50:02,960 Speaker 1: it's a string ball. And you know, science is a process. 1008 00:50:03,000 --> 00:50:05,160 Speaker 1: We start out with an idea and we get closer 1009 00:50:05,160 --> 00:50:07,279 Speaker 1: and closer to the truth. But you always have to 1010 00:50:07,320 --> 00:50:08,840 Speaker 1: keep in the back of your mind, what do we 1011 00:50:08,960 --> 00:50:12,160 Speaker 1: actually know? Have we really verified this? Is there a 1012 00:50:12,200 --> 00:50:15,560 Speaker 1: possibility for it to be something else, something other than 1013 00:50:15,600 --> 00:50:19,600 Speaker 1: the current theoretical idea, And so it's exciting to hear 1014 00:50:19,680 --> 00:50:22,320 Speaker 1: people thinking about what else black holes might be that 1015 00:50:22,360 --> 00:50:25,160 Speaker 1: would still look like the black holes we think we 1016 00:50:25,239 --> 00:50:28,440 Speaker 1: see out there in the universe. Right. Yeah, it's good 1017 00:50:28,480 --> 00:50:30,640 Speaker 1: to remember that this idea of a fastball is really 1018 00:50:30,800 --> 00:50:33,160 Speaker 1: just a theory, right, and in fact based on strength theory, 1019 00:50:33,160 --> 00:50:34,920 Speaker 1: which is sort of not like a real theory, It's 1020 00:50:34,920 --> 00:50:37,440 Speaker 1: more like a like a pet theory, right, more like 1021 00:50:37,440 --> 00:50:40,600 Speaker 1: a pepito theory. I do like to scratch the heads 1022 00:50:40,600 --> 00:50:42,680 Speaker 1: of string theories whenever I see them, just to give 1023 00:50:42,719 --> 00:50:46,000 Speaker 1: them some encouragement. That sounds really inappropriate, Daniel, Do you 1024 00:50:46,040 --> 00:50:48,720 Speaker 1: get consent before he's crashed their heads? They tend to purr. 1025 00:50:48,840 --> 00:50:51,239 Speaker 1: So what can I say? But yes, string theory is 1026 00:50:51,239 --> 00:50:54,480 Speaker 1: a speculative theory of what might be happening inside particles, 1027 00:50:54,520 --> 00:50:57,080 Speaker 1: and it makes this really fun prediction or what happens 1028 00:50:57,080 --> 00:50:58,600 Speaker 1: if you get like the mass of the sun in 1029 00:50:58,680 --> 00:51:01,319 Speaker 1: terms of strings and lease them all together. So it's 1030 00:51:01,360 --> 00:51:03,200 Speaker 1: a really fun prediction that would solve a bunch of 1031 00:51:03,200 --> 00:51:06,200 Speaker 1: problems and also be kind of awesome to think about. Yeah, 1032 00:51:06,239 --> 00:51:09,040 Speaker 1: at least in some universe, my not br universe, in 1033 00:51:09,160 --> 00:51:12,120 Speaker 1: some universe. Alright, Well, we hope you enjoyed that. Thanks 1034 00:51:12,160 --> 00:51:22,960 Speaker 1: for joining us, see you next time. Thanks for listening, 1035 00:51:22,960 --> 00:51:25,680 Speaker 1: and remember that Daniel and Jorge explained. The Universe is 1036 00:51:25,719 --> 00:51:29,120 Speaker 1: a production of I Heart Radio. For more podcast for 1037 00:51:29,239 --> 00:51:33,000 Speaker 1: my heart Radio, visit the i heart Radio app, Apple Podcasts, 1038 00:51:33,120 --> 00:51:35,480 Speaker 1: or wherever you listen to your favorite shows.