1 00:00:01,280 --> 00:00:03,320 Speaker 1: Hey, it' Jorhan Daniel here, and we want to tell 2 00:00:03,360 --> 00:00:06,880 Speaker 1: you about our new book. It's called Frequently Asked Questions 3 00:00:06,960 --> 00:00:09,719 Speaker 1: about the Universe because you have questions about the universe, 4 00:00:09,800 --> 00:00:12,399 Speaker 1: and so we decided to write a book all about them. 5 00:00:12,400 --> 00:00:14,800 Speaker 1: We talk about your questions, we give some answers, we 6 00:00:14,880 --> 00:00:17,520 Speaker 1: make a bunch of silly jokes as usual, and we 7 00:00:17,600 --> 00:00:20,159 Speaker 1: tackle all kinds of questions, including what happens if I 8 00:00:20,200 --> 00:00:22,880 Speaker 1: fall into a black hole? Or is there another version 9 00:00:22,920 --> 00:00:25,480 Speaker 1: of you out there that's right? Like usual, we tackle 10 00:00:25,600 --> 00:00:29,960 Speaker 1: the deepest, darkest, biggest, craziest questions about this incredible cosmos. 11 00:00:29,960 --> 00:00:31,800 Speaker 1: If you want to support the podcast, please get the 12 00:00:31,800 --> 00:00:33,879 Speaker 1: book and get a copy not just for yourself, but 13 00:00:34,120 --> 00:00:39,360 Speaker 1: you know, for your nieces and nephews, cousins, friends, parents, dogs, hamsters, 14 00:00:39,400 --> 00:00:42,640 Speaker 1: and for the aliens. So get your copy of Frequently 15 00:00:42,720 --> 00:00:46,440 Speaker 1: Asked Questions about the Universe is available for pre order now, 16 00:00:46,520 --> 00:00:49,239 Speaker 1: coming out November two. You can find more details at 17 00:00:49,240 --> 00:00:53,160 Speaker 1: the book's website, Universe f a Q dot com. Thanks 18 00:00:53,159 --> 00:00:55,000 Speaker 1: for your support, and if you have a hamster that 19 00:00:55,040 --> 00:00:57,240 Speaker 1: can read, please let us know. We'd love to have 20 00:00:57,320 --> 00:01:10,119 Speaker 1: them on the podcast. Hey, Jorge, why do you think 21 00:01:10,240 --> 00:01:14,560 Speaker 1: we get so many questions about black holes. Well, you know, 22 00:01:14,640 --> 00:01:17,760 Speaker 1: it's the mystery. You know, they're so inscrutable. They're like 23 00:01:18,000 --> 00:01:21,760 Speaker 1: the reclusive celebrities of the universe exactly right, Like the 24 00:01:21,800 --> 00:01:24,160 Speaker 1: more they avoid the paparazzi, the more people want to 25 00:01:24,160 --> 00:01:26,760 Speaker 1: know about them. That could be true, but I was 26 00:01:26,800 --> 00:01:30,040 Speaker 1: actually wondering if it might be the exact opposite. What 27 00:01:30,080 --> 00:01:31,960 Speaker 1: do you mean, Well, what if black holes are like 28 00:01:32,000 --> 00:01:34,520 Speaker 1: the car crash of the universe. They're like a cosmic 29 00:01:34,600 --> 00:01:37,600 Speaker 1: disaster that you can't drive by without slowing down to 30 00:01:37,680 --> 00:01:41,080 Speaker 1: check it out. Saying physicists are just rubber neckers, cosmic 31 00:01:41,120 --> 00:01:43,360 Speaker 1: rubber neckers. That sounds kind of dangerous, like you might 32 00:01:43,400 --> 00:01:46,560 Speaker 1: cause another accident by not watching where you were driving 33 00:01:46,560 --> 00:01:49,960 Speaker 1: your spaceship. Exactly. That's the gravitational runaway effects of the 34 00:01:50,000 --> 00:01:52,440 Speaker 1: black holes. Slow down to check it out, get sucked in, 35 00:01:52,680 --> 00:01:54,720 Speaker 1: make a bigger black hole. That's how I feel about 36 00:01:54,760 --> 00:01:57,440 Speaker 1: driving in Los Angeles. It's like an infinite black hole 37 00:01:57,560 --> 00:02:15,920 Speaker 1: that you will never escape. I am Jorge made cartoonists 38 00:02:15,919 --> 00:02:18,600 Speaker 1: and the creator of PhD comics. Hi, I'm Daniel. I'm 39 00:02:18,639 --> 00:02:21,519 Speaker 1: a particle physicist and a professor at U C. Irvine, 40 00:02:21,600 --> 00:02:24,640 Speaker 1: but I almost never go up to Los Angeles. Really 41 00:02:24,760 --> 00:02:28,440 Speaker 1: do you avoid it like a black hole. If it 42 00:02:28,480 --> 00:02:30,600 Speaker 1: was a black hole, it would suck me in. So yeah, 43 00:02:30,600 --> 00:02:33,080 Speaker 1: I'm trying to stay in orbit around Los Angeles instead 44 00:02:33,080 --> 00:02:36,760 Speaker 1: of falling into the singularity, yes, where time slows down 45 00:02:36,919 --> 00:02:39,880 Speaker 1: through plastic surgery apparently. But yeah, I mean you're kind 46 00:02:39,880 --> 00:02:42,040 Speaker 1: of famous now, Daniel. You don't get calls from Hollywood 47 00:02:42,080 --> 00:02:45,120 Speaker 1: these days. I screened my calls, so if they're calling, 48 00:02:45,160 --> 00:02:46,840 Speaker 1: I'm just not picking them up. You look for the 49 00:02:46,880 --> 00:02:49,440 Speaker 1: aira code. If it's your local air code, it's ma'am. 50 00:02:49,480 --> 00:02:51,720 Speaker 1: If it's three one oh, then it's someone from Hollywood, 51 00:02:51,880 --> 00:02:54,000 Speaker 1: like Jorge, so you just hang up. Also, you know, 52 00:02:54,080 --> 00:02:56,480 Speaker 1: there's famous and then there's Los Angeles famous. You can 53 00:02:56,560 --> 00:02:59,240 Speaker 1: be like super famous in Orange County and be nobody 54 00:02:59,280 --> 00:03:02,040 Speaker 1: in Los Angeles. But anyways, welcome to our podcast, Daniel 55 00:03:02,080 --> 00:03:04,960 Speaker 1: and Jorge Explain the Universe, a production of I Heart Radio, 56 00:03:05,080 --> 00:03:07,920 Speaker 1: in which we ask all the biggest and famous and 57 00:03:08,040 --> 00:03:12,000 Speaker 1: most time dilated questions of the universe. We ask all 58 00:03:12,000 --> 00:03:14,320 Speaker 1: of them about where it came from, where it's going, 59 00:03:14,440 --> 00:03:16,720 Speaker 1: what it's made out of, and how it all works. 60 00:03:16,840 --> 00:03:19,480 Speaker 1: We dive deep into the questions about black holes and 61 00:03:19,560 --> 00:03:23,640 Speaker 1: neutron stars and galaxies and tiny particles and quaisars and 62 00:03:23,760 --> 00:03:26,760 Speaker 1: everything in between, because we think it's possible to download 63 00:03:26,840 --> 00:03:29,920 Speaker 1: all of that into your amazing brain and hold for 64 00:03:29,960 --> 00:03:33,959 Speaker 1: a moment an understanding of the entire universe. Yeah, because 65 00:03:33,960 --> 00:03:36,720 Speaker 1: it is a pretty famous universe. Everyone seems to know 66 00:03:36,800 --> 00:03:39,680 Speaker 1: about it. Everyone's fan. I would hope, you know, it's 67 00:03:39,720 --> 00:03:42,320 Speaker 1: everywhere he got. He can't get away from this universe, 68 00:03:42,400 --> 00:03:45,320 Speaker 1: and it's pretty fascinating, even it's black sheep. You know, 69 00:03:45,360 --> 00:03:48,120 Speaker 1: everyone wants to know about the black Sheep of the celebrities. Yes, 70 00:03:48,200 --> 00:03:51,200 Speaker 1: have you been checking out the universe's reviews on yelp? Yes, 71 00:03:51,280 --> 00:03:54,280 Speaker 1: I think it. It has about infinite stars and also 72 00:03:54,400 --> 00:03:57,760 Speaker 1: infinite thumbs, but you know it's about fifty up and them. 73 00:03:57,920 --> 00:04:00,720 Speaker 1: That's right, And you know nobody has any other are alternatives. 74 00:04:00,760 --> 00:04:02,360 Speaker 1: It's not like people like, hey, I was in this 75 00:04:02,440 --> 00:04:05,040 Speaker 1: other universe the other day and they have better chips. 76 00:04:05,360 --> 00:04:07,800 Speaker 1: So you know, this is basically all we got learned 77 00:04:07,800 --> 00:04:09,320 Speaker 1: to love at people. Maybe you just need to get 78 00:04:09,360 --> 00:04:11,800 Speaker 1: out more than you You might find other universes if 79 00:04:11,840 --> 00:04:13,880 Speaker 1: you just, you know, get out of your Orange County 80 00:04:13,880 --> 00:04:17,000 Speaker 1: Bubble l A does seem like another universe sometimes, not 81 00:04:17,080 --> 00:04:19,320 Speaker 1: just because it's weird, but because it takes forever to 82 00:04:19,400 --> 00:04:24,200 Speaker 1: get there. Definitely an alternate reality for sure. But anyways, Yeah, 83 00:04:24,600 --> 00:04:27,080 Speaker 1: people are curious not just about the universe but about 84 00:04:27,120 --> 00:04:30,680 Speaker 1: the things in it, especially things that are extra mysterious, 85 00:04:30,680 --> 00:04:33,200 Speaker 1: and those are the things that drive physics. We look 86 00:04:33,240 --> 00:04:35,200 Speaker 1: around in the universe and we say, do we understand 87 00:04:35,200 --> 00:04:37,839 Speaker 1: how this works? Does that bit over there makes sense? 88 00:04:38,040 --> 00:04:40,279 Speaker 1: And if it doesn't, then we focus our brains on 89 00:04:40,320 --> 00:04:42,800 Speaker 1: and try to understand how could that possibly work? How 90 00:04:42,839 --> 00:04:45,040 Speaker 1: could that make sense? How could that be consistent with 91 00:04:45,120 --> 00:04:48,000 Speaker 1: what we know about the nature of space and time 92 00:04:48,120 --> 00:04:51,440 Speaker 1: and energy, And so the weirdest things are also the 93 00:04:51,480 --> 00:04:55,040 Speaker 1: best opportunities to learn something about the universe. Yeah, because 94 00:04:55,040 --> 00:04:56,920 Speaker 1: when you look around, I guess it's all pretty bright 95 00:04:56,960 --> 00:05:00,040 Speaker 1: and beautiful and majestic and cosmic, but everyone's in a 96 00:05:00,120 --> 00:05:01,680 Speaker 1: When you look at into the universe, there is a 97 00:05:02,279 --> 00:05:04,520 Speaker 1: basically a big hole, like a big hole in our 98 00:05:04,560 --> 00:05:08,400 Speaker 1: knowledge and also literally figuratively and in all the ways 99 00:05:08,520 --> 00:05:11,520 Speaker 1: there there are actual holes in the universe. There are 100 00:05:11,640 --> 00:05:13,400 Speaker 1: holes in the universe, and you know, to answer the 101 00:05:13,480 --> 00:05:15,640 Speaker 1: question to our intro. I think one reason that they're 102 00:05:15,680 --> 00:05:19,800 Speaker 1: fascinating is because they are so different from what we experience. 103 00:05:19,920 --> 00:05:22,120 Speaker 1: You know, it's not just like, hey, there's a banana 104 00:05:22,160 --> 00:05:24,760 Speaker 1: out there in space, like we know bananas, We bananas, 105 00:05:24,760 --> 00:05:27,320 Speaker 1: were familiar with bananas. You know, it's something out there 106 00:05:27,320 --> 00:05:30,640 Speaker 1: in space which is so different from our everyday experience, 107 00:05:30,720 --> 00:05:33,240 Speaker 1: so bizarre that we just sort of like want to 108 00:05:33,240 --> 00:05:35,159 Speaker 1: see it. Yeah, and so to be on the podcast, 109 00:05:35,240 --> 00:05:45,280 Speaker 1: we'll be tackling unanswered questions about black holes. Now, Daniel, 110 00:05:45,320 --> 00:05:49,480 Speaker 1: I assume it's not just bananas out there. We don't know, 111 00:05:49,520 --> 00:05:52,039 Speaker 1: you know, maybe bananas are the fundamental element of the 112 00:05:52,120 --> 00:05:54,880 Speaker 1: universe and it is just all bananas all the way down. 113 00:05:55,320 --> 00:05:58,800 Speaker 1: That's a viable theory. It sounds like a slippery slope there. 114 00:06:00,760 --> 00:06:03,479 Speaker 1: We just gotta peel back the layers of reality until 115 00:06:03,520 --> 00:06:07,920 Speaker 1: we reveal the banana inside. But yeah, black holes. A 116 00:06:07,960 --> 00:06:10,200 Speaker 1: lot of people have questions about black holes, and you're 117 00:06:10,240 --> 00:06:13,000 Speaker 1: asking me earlier why they're so mysterious. Like everyone, you 118 00:06:13,040 --> 00:06:15,200 Speaker 1: get a lot of questions about black holes, right, Yeah, 119 00:06:15,240 --> 00:06:17,080 Speaker 1: I say like a third of all the questions we 120 00:06:17,160 --> 00:06:19,400 Speaker 1: get are about black holes. What happens if you fall 121 00:06:19,480 --> 00:06:21,280 Speaker 1: in them, What would they look like if you did this? 122 00:06:21,480 --> 00:06:23,320 Speaker 1: What would happen if you shoot two black holes at 123 00:06:23,320 --> 00:06:25,760 Speaker 1: each other? All sorts of questions people love to think 124 00:06:25,760 --> 00:06:30,160 Speaker 1: about black holes. Interesting a third of the questions. That's amazing. 125 00:06:30,440 --> 00:06:33,520 Speaker 1: It's like, it's some black hole in your It does 126 00:06:33,600 --> 00:06:36,359 Speaker 1: make my inbox pretty dense. But I love it. I 127 00:06:36,400 --> 00:06:38,640 Speaker 1: love thinking about black holes just as much as our 128 00:06:38,640 --> 00:06:41,080 Speaker 1: listeners do for the same reasons, you know. And the 129 00:06:41,120 --> 00:06:44,080 Speaker 1: cool thing about black holes is that we all understand 130 00:06:44,160 --> 00:06:46,440 Speaker 1: them about as well, you know. I love that we 131 00:06:46,440 --> 00:06:48,880 Speaker 1: can bring our listeners to the very forefront of knowledge, 132 00:06:48,920 --> 00:06:50,800 Speaker 1: because in the case of black holes, it's not that 133 00:06:50,920 --> 00:06:53,880 Speaker 1: far away. You know. We just don't understand very much 134 00:06:54,120 --> 00:06:57,159 Speaker 1: about these weird, mysterious objects. I think that's why they're 135 00:06:57,160 --> 00:07:00,640 Speaker 1: so fascinating to physicists, because they represent such a great 136 00:07:00,680 --> 00:07:04,280 Speaker 1: opportunity to learn something new and shocking about the universe. Yeah, 137 00:07:04,320 --> 00:07:07,520 Speaker 1: so today we're answering questions that we've gotten about black 138 00:07:07,520 --> 00:07:10,200 Speaker 1: holes from listener. It's just like you, and we've got 139 00:07:10,240 --> 00:07:13,480 Speaker 1: three pretty interesting questions, one of them about the mass 140 00:07:13,520 --> 00:07:17,440 Speaker 1: of a black hole, about mini black holes, and also 141 00:07:17,600 --> 00:07:20,920 Speaker 1: about whether or not black holes can explain dark matter. 142 00:07:21,520 --> 00:07:23,920 Speaker 1: So let's jump into our first question right away here, 143 00:07:23,960 --> 00:07:27,800 Speaker 1: and it comes from Levi from the Ukraine. I didn't 144 00:07:27,800 --> 00:07:31,880 Speaker 1: know m Levi are Ukraine, and I had two questions 145 00:07:31,920 --> 00:07:36,239 Speaker 1: about my favorite topic, which is black holes. First, how 146 00:07:36,560 --> 00:07:40,320 Speaker 1: is the mass of a black hole calculated? And second? 147 00:07:41,120 --> 00:07:44,000 Speaker 1: Is there anybody to know when an event horizon of 148 00:07:44,040 --> 00:07:46,720 Speaker 1: a black hole begins? If I were to say, take 149 00:07:46,720 --> 00:07:48,440 Speaker 1: a rocket ship to the black hole and this sene 150 00:07:48,520 --> 00:07:50,920 Speaker 1: our galaxy, is there any way that I could know 151 00:07:51,120 --> 00:07:53,400 Speaker 1: when I need to turn that thing around before I 152 00:07:53,520 --> 00:07:58,040 Speaker 1: become spaghetti? Thank you? M M. Interesting question? Now? Was 153 00:07:58,080 --> 00:07:59,960 Speaker 1: he allowed two questions? I feel like he's not good 154 00:08:00,080 --> 00:08:03,440 Speaker 1: extra question in his question imploded into a black hole 155 00:08:03,480 --> 00:08:06,520 Speaker 1: because of its density, he had it multiplied. It seems 156 00:08:07,160 --> 00:08:09,520 Speaker 1: so you just can't stop asking questions. Once you start 157 00:08:09,520 --> 00:08:12,720 Speaker 1: thinking about black holes, the questions just proliferate. What do 158 00:08:12,720 --> 00:08:15,400 Speaker 1: you think it's captured the imagination of not just our listeners, 159 00:08:15,400 --> 00:08:18,080 Speaker 1: but it seems like everyone out there has questions about 160 00:08:18,080 --> 00:08:21,040 Speaker 1: black holes. I think it's just the opportunity to see 161 00:08:21,120 --> 00:08:23,880 Speaker 1: something hidden, to learn something new. You know. The thing 162 00:08:23,920 --> 00:08:26,720 Speaker 1: that captivates me about the black hole is knowing that 163 00:08:26,800 --> 00:08:29,920 Speaker 1: one of the greatest mysteries in modern physics. How to 164 00:08:30,080 --> 00:08:35,080 Speaker 1: reconcile crazy intense gravity and quantum little particles, how to 165 00:08:35,120 --> 00:08:37,880 Speaker 1: bring those together into one idea is out there, and 166 00:08:37,920 --> 00:08:40,360 Speaker 1: it's hidden inside a black hole. So if we could 167 00:08:40,360 --> 00:08:43,600 Speaker 1: only peek inside, we could learn the very nature of 168 00:08:43,720 --> 00:08:46,679 Speaker 1: space and time. There's so much we could know by 169 00:08:46,679 --> 00:08:49,280 Speaker 1: the universe if only we could see inside a black hole. 170 00:08:49,320 --> 00:08:51,720 Speaker 1: And yet he's hidden from us. So it's sort of 171 00:08:51,760 --> 00:08:54,520 Speaker 1: like somebody saying, I have the secrets you want, and 172 00:08:54,520 --> 00:08:56,920 Speaker 1: they're written on this envelope and I'm gonna burn it. 173 00:08:56,960 --> 00:08:58,880 Speaker 1: I'm gonna throw in the fire instead of opening it 174 00:08:58,880 --> 00:09:01,319 Speaker 1: to you. That would kill you. Oh man, if you's 175 00:09:01,360 --> 00:09:03,800 Speaker 1: so frustrating to know the answers are out there and 176 00:09:03,960 --> 00:09:06,160 Speaker 1: not be able to get them, that's very frustrating. These 177 00:09:06,160 --> 00:09:08,240 Speaker 1: there a big red button into that envelope. That would 178 00:09:08,400 --> 00:09:11,480 Speaker 1: drive doubly crazy. But all right, let's jump into Levi's 179 00:09:11,520 --> 00:09:13,880 Speaker 1: questions here. The first one is how do you calculate 180 00:09:13,920 --> 00:09:16,920 Speaker 1: the mass of a black hole? Now I'm guessing down 181 00:09:17,000 --> 00:09:20,679 Speaker 1: or there are not gigantic scales we can use to 182 00:09:20,760 --> 00:09:23,400 Speaker 1: measure the mass of a black hole, A sort of 183 00:09:23,400 --> 00:09:26,960 Speaker 1: if we can Yeah, scales work by using gravity. Right, 184 00:09:27,080 --> 00:09:29,880 Speaker 1: If you put something on a scale, you're measuring its weight, 185 00:09:30,120 --> 00:09:32,559 Speaker 1: and its weight is the force of gravity on it, 186 00:09:32,760 --> 00:09:35,559 Speaker 1: which is determined by its mass. And so to measure 187 00:09:35,600 --> 00:09:37,680 Speaker 1: the mass of something you can use the strength of 188 00:09:37,679 --> 00:09:41,600 Speaker 1: the gravitational pull on it, which depends on the object's mass. 189 00:09:41,600 --> 00:09:43,480 Speaker 1: Now out there in space, You're right, there's not some 190 00:09:43,600 --> 00:09:45,960 Speaker 1: like massive scale we can put it on. But we 191 00:09:46,040 --> 00:09:49,640 Speaker 1: can see how the black hole tugs on things around 192 00:09:49,679 --> 00:09:52,000 Speaker 1: it which are visible, and that's one way we can 193 00:09:52,040 --> 00:09:54,439 Speaker 1: measure its mass, and so you can see the effects 194 00:09:54,440 --> 00:09:56,840 Speaker 1: of its mass on the things around it. I guess 195 00:09:56,880 --> 00:09:58,720 Speaker 1: kind of like our son, right, Like if our son 196 00:09:59,400 --> 00:10:01,720 Speaker 1: with a different and mass, like if it was bigger 197 00:10:01,800 --> 00:10:05,040 Speaker 1: or smaller than our orbit around it would be different. Right, 198 00:10:05,240 --> 00:10:07,280 Speaker 1: Like you could tell what the mass of the Sun 199 00:10:07,360 --> 00:10:10,000 Speaker 1: is maybe from our orbit. Yeah, if you measure just 200 00:10:10,080 --> 00:10:12,840 Speaker 1: the velocity and location of the Earth as it moved 201 00:10:12,880 --> 00:10:15,440 Speaker 1: around the Sun, you can deduce exactly the mass of 202 00:10:15,440 --> 00:10:18,200 Speaker 1: the Sun because you can tell what gravitational force is 203 00:10:18,280 --> 00:10:21,560 Speaker 1: necessary to move the Earth in that path, and that 204 00:10:21,559 --> 00:10:23,880 Speaker 1: would tell you how much mass you need to provide 205 00:10:23,880 --> 00:10:26,680 Speaker 1: that gravitational force. So, yeah, the Earth is like a 206 00:10:26,679 --> 00:10:29,320 Speaker 1: little scale that's measuring the Sun all the time. But 207 00:10:29,360 --> 00:10:30,720 Speaker 1: what do you need to know the mass of the 208 00:10:30,760 --> 00:10:33,720 Speaker 1: Earth too, pretty accurately? Yes, absolutely, you need to know 209 00:10:33,760 --> 00:10:35,240 Speaker 1: the mass of the Earth. And don't say you just 210 00:10:35,360 --> 00:10:39,280 Speaker 1: use the sun, because then now we're in a circular argument. No, 211 00:10:39,440 --> 00:10:41,280 Speaker 1: you need to use the mass of the Earth. Absolutely. 212 00:10:41,320 --> 00:10:43,080 Speaker 1: The mass of the Earth you can get using like 213 00:10:43,400 --> 00:10:46,280 Speaker 1: your knowledge of what it's made out of and it's volume. 214 00:10:46,360 --> 00:10:47,960 Speaker 1: So if you know the radius of the Earth, like 215 00:10:48,000 --> 00:10:50,679 Speaker 1: its size, and your understanding roughly what it's made out of, 216 00:10:50,840 --> 00:10:53,640 Speaker 1: then you can tell its mass, or you can bootstrap. 217 00:10:53,679 --> 00:10:55,200 Speaker 1: You can say, well, I'm gonna look at the moon 218 00:10:55,280 --> 00:10:57,040 Speaker 1: and see how the moon moves around the Earth, and 219 00:10:57,040 --> 00:10:58,600 Speaker 1: that's going to tell me the mass of the Earth 220 00:10:58,679 --> 00:11:02,079 Speaker 1: if again you know the mass to the moon. Yeah, 221 00:11:02,120 --> 00:11:04,439 Speaker 1: and so on and so on. I guess at some point, 222 00:11:04,480 --> 00:11:06,960 Speaker 1: maybe the question is at some point when do you 223 00:11:06,960 --> 00:11:09,640 Speaker 1: have to guess? Right, because something you have to guess 224 00:11:09,679 --> 00:11:11,800 Speaker 1: what the moon is made out of, or even the 225 00:11:11,840 --> 00:11:13,679 Speaker 1: Earth you cannot have to guess. I mean, we have 226 00:11:13,760 --> 00:11:17,000 Speaker 1: some measurements, but we ultimately you're sort of guessing what's 227 00:11:17,000 --> 00:11:19,040 Speaker 1: inside the Earth. Yeah, in the end, you do need 228 00:11:19,120 --> 00:11:20,760 Speaker 1: to know the mass of one of the objects to 229 00:11:20,760 --> 00:11:23,079 Speaker 1: measure the mass the other. But there's also some constraints. 230 00:11:23,080 --> 00:11:25,040 Speaker 1: They're like, what you really need to know is the 231 00:11:25,080 --> 00:11:29,120 Speaker 1: product of the two masses, right, mass one times mass too. 232 00:11:29,440 --> 00:11:32,320 Speaker 1: So if you make enough measurements of pairs of objects 233 00:11:32,400 --> 00:11:34,560 Speaker 1: and you can narrow that down, you get like enough 234 00:11:34,600 --> 00:11:37,640 Speaker 1: systems of equations that you can constrain it. But yeah, 235 00:11:37,679 --> 00:11:39,720 Speaker 1: you also do need to say something about what they 236 00:11:39,720 --> 00:11:41,800 Speaker 1: are made out of to get some information about how 237 00:11:41,880 --> 00:11:43,800 Speaker 1: much mass one of them has. You can also measure 238 00:11:43,800 --> 00:11:46,320 Speaker 1: the mass of the Earth by flipping that around and saying, here, 239 00:11:46,360 --> 00:11:48,559 Speaker 1: I have an object whose mass I know, and that 240 00:11:48,640 --> 00:11:51,400 Speaker 1: can measure the gravitational effect on it, and from that 241 00:11:51,440 --> 00:11:53,360 Speaker 1: I can measure the mass of the Earth. To build 242 00:11:53,400 --> 00:11:55,760 Speaker 1: like a calibration object, like a test object, like a 243 00:11:55,800 --> 00:11:59,120 Speaker 1: one kilogram pound of platinum or something. Yeah, you can 244 00:11:59,160 --> 00:12:02,160 Speaker 1: see how much it pulls on like a known weight, 245 00:12:02,320 --> 00:12:04,280 Speaker 1: and then that's how you would estimate the mass of 246 00:12:04,280 --> 00:12:06,560 Speaker 1: the Earth. And that's just sort of definition. All you say, like, 247 00:12:06,800 --> 00:12:09,600 Speaker 1: this is the definition of a kilogram this object, and 248 00:12:09,640 --> 00:12:12,480 Speaker 1: from that you can measure essentially the ratio of its 249 00:12:12,559 --> 00:12:14,480 Speaker 1: mass to the mass of the Earth. You can say 250 00:12:14,520 --> 00:12:17,400 Speaker 1: how massive is the Earth in terms of this object 251 00:12:17,679 --> 00:12:19,800 Speaker 1: I'm defining to be one kilogram, and then you can 252 00:12:19,840 --> 00:12:22,760 Speaker 1: bootstrap your way up to the Sun and basically everything 253 00:12:22,760 --> 00:12:24,880 Speaker 1: else in the universe. Right, you can strap your boot. 254 00:12:24,920 --> 00:12:27,240 Speaker 1: You can boot your strap. But what about for like 255 00:12:27,280 --> 00:12:30,240 Speaker 1: a black hole? I mean, they're so far away, we've 256 00:12:30,280 --> 00:12:33,000 Speaker 1: barely seen one directly. You know, we can see the 257 00:12:33,120 --> 00:12:35,720 Speaker 1: things flying around it, But how do we know what 258 00:12:35,840 --> 00:12:38,760 Speaker 1: those things are? I mean, they're just like bright little pinpoints, right, yes, 259 00:12:38,800 --> 00:12:40,959 Speaker 1: So one way we can see the black holes exist 260 00:12:41,200 --> 00:12:44,480 Speaker 1: is by seeing their gravitational effect on stuff nearby. Because 261 00:12:44,520 --> 00:12:47,240 Speaker 1: black holes, of course are black, they don't admit any 262 00:12:47,360 --> 00:12:50,520 Speaker 1: radiation directly, or if they're emitting hawking radiation, then we 263 00:12:50,559 --> 00:12:52,560 Speaker 1: can't see it. It's too faint. So you're right, we 264 00:12:52,600 --> 00:12:54,920 Speaker 1: need to know the mass of the objects nearby. And so, 265 00:12:55,000 --> 00:12:58,520 Speaker 1: for example, the black hole the center of our galaxy 266 00:12:58,640 --> 00:13:01,640 Speaker 1: has some stars whizzing very close by to it, and 267 00:13:01,679 --> 00:13:04,360 Speaker 1: we can measure the mass of those stars by looking 268 00:13:04,400 --> 00:13:06,480 Speaker 1: at the light they emit, because we have a pretty 269 00:13:06,480 --> 00:13:08,960 Speaker 1: good model for how the brightness of a star is 270 00:13:09,000 --> 00:13:11,840 Speaker 1: related to its mass. So we did a whole episode 271 00:13:11,840 --> 00:13:14,160 Speaker 1: on how you measure the mass of stars. And that's 272 00:13:14,200 --> 00:13:17,040 Speaker 1: not perfect, it's not exact, but it's pretty good, right, 273 00:13:17,040 --> 00:13:20,200 Speaker 1: it's based on like models and some observations, and so 274 00:13:20,400 --> 00:13:22,079 Speaker 1: just from the light that you get from those stars 275 00:13:22,120 --> 00:13:24,440 Speaker 1: around the black hole, you can say, well, that's a 276 00:13:24,440 --> 00:13:27,800 Speaker 1: a stage so and so star weighs about they usually 277 00:13:27,960 --> 00:13:30,319 Speaker 1: wait about this much and so there, and it's curving 278 00:13:30,360 --> 00:13:33,360 Speaker 1: around the black hole this much. So therefore that black 279 00:13:33,360 --> 00:13:37,160 Speaker 1: holes probably there's many kilograms exactly. And those models are 280 00:13:37,160 --> 00:13:40,000 Speaker 1: pretty good, and we validate them using binary star systems 281 00:13:40,040 --> 00:13:42,480 Speaker 1: where we can see two stars, we can measure their brightness, 282 00:13:42,520 --> 00:13:44,320 Speaker 1: and we can see how they move around each other, 283 00:13:44,640 --> 00:13:47,120 Speaker 1: and so we can really validate those models pretty well. 284 00:13:47,160 --> 00:13:49,199 Speaker 1: I mean, there are uncertainties, but we can trust those 285 00:13:49,200 --> 00:13:51,640 Speaker 1: because remember there are a lot of binary star systems 286 00:13:51,640 --> 00:13:54,040 Speaker 1: out there in the universe, many more than you might expect. 287 00:13:54,120 --> 00:13:55,920 Speaker 1: So that lets us measure the mass of the stars 288 00:13:55,960 --> 00:13:58,120 Speaker 1: and from that deduced the mass of the black hole. 289 00:13:58,200 --> 00:14:01,320 Speaker 1: Because remember, black holes don't emit any information from their 290 00:14:01,360 --> 00:14:05,280 Speaker 1: inside except for the total mass of the black hole, 291 00:14:05,320 --> 00:14:08,680 Speaker 1: which can be deduced by its gravitational effect. That's the 292 00:14:08,720 --> 00:14:11,280 Speaker 1: only information that comes out other than the black holes 293 00:14:11,360 --> 00:14:13,959 Speaker 1: spin and charge. And also do you have to account 294 00:14:13,960 --> 00:14:16,160 Speaker 1: for like the camera adding ten pounds, like does the 295 00:14:16,240 --> 00:14:19,680 Speaker 1: telescope at you know, ten million kims? No, the black 296 00:14:19,720 --> 00:14:22,240 Speaker 1: holes agent is very particular by the cameras. We used 297 00:14:22,240 --> 00:14:25,160 Speaker 1: to take their pictures nicely. These is doubles. When it's 298 00:14:25,200 --> 00:14:27,560 Speaker 1: taking the naked pictures. I said, take a profile above 299 00:14:27,600 --> 00:14:29,800 Speaker 1: the accretion disk. That's when it looks good, all right. 300 00:14:29,840 --> 00:14:31,720 Speaker 1: And there's also sort of a different way to measure 301 00:14:31,760 --> 00:14:33,400 Speaker 1: the mass of a black hole, which is by looking 302 00:14:33,440 --> 00:14:36,080 Speaker 1: at its size. Like if we ever do get better 303 00:14:36,120 --> 00:14:38,240 Speaker 1: pictures of a black hole, you might be able to 304 00:14:38,240 --> 00:14:41,120 Speaker 1: tell how heavy it is by just seeing its size, right, 305 00:14:41,160 --> 00:14:44,000 Speaker 1: Because the size of the event horizon depends on the 306 00:14:44,040 --> 00:14:46,360 Speaker 1: mass of the black hole. Yeah, they're very closely connected. 307 00:14:46,440 --> 00:14:48,680 Speaker 1: As the black hole eats more and gets more mass 308 00:14:49,000 --> 00:14:51,760 Speaker 1: than it is gaining in size, the size the event 309 00:14:51,800 --> 00:14:55,160 Speaker 1: horizon is growing, and so if you could measure the 310 00:14:55,200 --> 00:14:58,200 Speaker 1: event horizon, then you could deduce its mass. Measuring the 311 00:14:58,200 --> 00:15:00,480 Speaker 1: event horizon is tricky though, because you need to see 312 00:15:00,520 --> 00:15:03,560 Speaker 1: photons like whizzing around it. So you need a direct 313 00:15:03,560 --> 00:15:06,120 Speaker 1: picture and we've done that for one, maybe two black 314 00:15:06,120 --> 00:15:08,760 Speaker 1: holes now. But it's much harder, obviously, And so that 315 00:15:08,760 --> 00:15:11,040 Speaker 1: brings us to the second question leave I had, which 316 00:15:11,160 --> 00:15:13,880 Speaker 1: is like, if I'm trying to check out a black hole, like, 317 00:15:13,960 --> 00:15:17,520 Speaker 1: could I tell where the actual event horizon is? Like, 318 00:15:17,680 --> 00:15:19,560 Speaker 1: at what point do you want to make sure you 319 00:15:19,960 --> 00:15:22,160 Speaker 1: turn around before you get sucked in forever? Well, I 320 00:15:22,200 --> 00:15:24,360 Speaker 1: would say turn around now, do not take that trip 321 00:15:24,400 --> 00:15:28,240 Speaker 1: to the black hole. It's not a good idea. Don't 322 00:15:28,240 --> 00:15:30,600 Speaker 1: even buy the ticket sets when you should turn around. Right, 323 00:15:30,640 --> 00:15:33,320 Speaker 1: So it is a good idea to think about where 324 00:15:33,320 --> 00:15:36,480 Speaker 1: a black hole begins, where it's event horizon is, so 325 00:15:36,520 --> 00:15:40,000 Speaker 1: that if you are a billionaire scientist, entrepreneur and you 326 00:15:40,040 --> 00:15:42,320 Speaker 1: do take that trip to the center of the Milky 327 00:15:42,360 --> 00:15:44,840 Speaker 1: Way to study the black hole, you know when to 328 00:15:44,920 --> 00:15:47,560 Speaker 1: turn around. And one thing you could do, if you 329 00:15:47,640 --> 00:15:49,560 Speaker 1: know the mass of the black hole is, you could 330 00:15:49,600 --> 00:15:51,280 Speaker 1: just calculate it. You could say, well, I know how 331 00:15:51,320 --> 00:15:53,960 Speaker 1: massive it is, so I know the point of no return. 332 00:15:54,000 --> 00:15:57,120 Speaker 1: I can calculate the event horizon. So, yeah, there's a 333 00:15:57,160 --> 00:15:59,240 Speaker 1: point at a distance from the center of the black 334 00:15:59,240 --> 00:16:01,560 Speaker 1: hole at which now even light can escape, right. I 335 00:16:01,560 --> 00:16:03,680 Speaker 1: think maybe that's what LEVI is asking, Like, what's the 336 00:16:03,720 --> 00:16:06,840 Speaker 1: point where not even light can escape. That's the event horizon, 337 00:16:07,320 --> 00:16:09,800 Speaker 1: and from a distance you can sort of see it, right, Like, 338 00:16:09,960 --> 00:16:12,600 Speaker 1: it's sort of where when you look at a black hole, 339 00:16:12,920 --> 00:16:15,240 Speaker 1: and we've looked at one, it looks like a big 340 00:16:15,280 --> 00:16:18,880 Speaker 1: black circle, and so that's generally where the event horizon is, 341 00:16:18,920 --> 00:16:21,400 Speaker 1: although it's not exact right. That's right, the black circle 342 00:16:21,480 --> 00:16:23,560 Speaker 1: you see when you look at a black hole is 343 00:16:23,600 --> 00:16:26,760 Speaker 1: actually bigger than the event horizon because you can't see 344 00:16:26,800 --> 00:16:30,440 Speaker 1: photons that like fly just above the event horizon from 345 00:16:30,440 --> 00:16:33,200 Speaker 1: behind the black hole. Those we get curved and fall 346 00:16:33,280 --> 00:16:36,080 Speaker 1: into the black hole. So there's the event horizon itself, 347 00:16:36,280 --> 00:16:38,400 Speaker 1: and then there's like a shadow that the black hole 348 00:16:38,480 --> 00:16:41,280 Speaker 1: makes that's even larger than the event horizon. You can 349 00:16:41,400 --> 00:16:43,880 Speaker 1: get closer than the shadow, you see it looks bigger 350 00:16:43,920 --> 00:16:46,360 Speaker 1: than it actually is. And as you get closer and 351 00:16:46,440 --> 00:16:49,720 Speaker 1: closer to the black hole, that shadow grows and it 352 00:16:49,760 --> 00:16:52,240 Speaker 1: grows to take over more and more of your view. 353 00:16:52,480 --> 00:16:54,680 Speaker 1: So if you're very close to the black hole, for example, 354 00:16:54,720 --> 00:16:56,840 Speaker 1: then it might appear to take up like half of 355 00:16:56,840 --> 00:16:59,960 Speaker 1: your entire view. Right. That's kind of the tricky thing 356 00:17:00,000 --> 00:17:02,880 Speaker 1: about black holes is that there's so much distortion around 357 00:17:02,920 --> 00:17:04,879 Speaker 1: them that you know, from afar, they look like a 358 00:17:05,000 --> 00:17:08,720 Speaker 1: nice clean circle, But as you get closer, everything gets 359 00:17:08,760 --> 00:17:11,560 Speaker 1: distorted and kind of blown out of proportion, and so 360 00:17:11,600 --> 00:17:14,560 Speaker 1: it's gonna be really hard to tell when you've reached 361 00:17:14,600 --> 00:17:17,320 Speaker 1: the actual event horizon, right, because, like you're saying, the 362 00:17:17,359 --> 00:17:19,240 Speaker 1: black hole is gonna start taking a bit more and 363 00:17:19,280 --> 00:17:21,520 Speaker 1: more of your field of view, and you're gonna be 364 00:17:21,560 --> 00:17:23,080 Speaker 1: like in my inn or am I out? I don't know, 365 00:17:23,240 --> 00:17:25,919 Speaker 1: yeah exactly, And so this is very dangerous not to 366 00:17:25,920 --> 00:17:28,639 Speaker 1: be recommended or endorsed. But as you get closer and 367 00:17:28,640 --> 00:17:30,840 Speaker 1: closer to the black hole, the image of it grows 368 00:17:31,040 --> 00:17:33,640 Speaker 1: larger and larger, and as you say, what you're seeing 369 00:17:33,840 --> 00:17:37,040 Speaker 1: is not anymore a good representation of what's actually there. 370 00:17:37,320 --> 00:17:39,720 Speaker 1: Like when you look around yourself in your room, the 371 00:17:39,760 --> 00:17:41,919 Speaker 1: stuff you see is the stuff that's there, because the 372 00:17:41,960 --> 00:17:44,119 Speaker 1: light is moving in a straight line from whatever it 373 00:17:44,240 --> 00:17:46,080 Speaker 1: is to your eyes, and so you can look around 374 00:17:46,119 --> 00:17:48,320 Speaker 1: and say, oh, that's over there and this is over here. 375 00:17:48,400 --> 00:17:50,920 Speaker 1: But if there are like lenses around you that bend 376 00:17:50,960 --> 00:17:53,480 Speaker 1: the light, then you get distorted images. Imagine you're in 377 00:17:53,480 --> 00:17:55,920 Speaker 1: a fun house mirror. What you see is not what's 378 00:17:55,960 --> 00:17:58,200 Speaker 1: actually there, and that's what's happening with the black hole. 379 00:17:58,320 --> 00:18:00,879 Speaker 1: Light is no longer following straight lines, so what you 380 00:18:00,920 --> 00:18:03,480 Speaker 1: see is a distortion. And it's really interesting. As you 381 00:18:03,520 --> 00:18:05,919 Speaker 1: get closer and closer to the black hole than the 382 00:18:05,920 --> 00:18:08,919 Speaker 1: shadow of the black hole, this big black image of 383 00:18:08,960 --> 00:18:12,720 Speaker 1: the event horizon gets larger and larger eventually becomes more 384 00:18:12,760 --> 00:18:15,679 Speaker 1: than just half of your view. It like takes up 385 00:18:15,800 --> 00:18:17,800 Speaker 1: most of your view, and the rest of the universe 386 00:18:17,880 --> 00:18:20,919 Speaker 1: is squeezed down into a smaller and smaller circle. And 387 00:18:20,960 --> 00:18:22,720 Speaker 1: you can get a clue about when you're back to 388 00:18:22,760 --> 00:18:25,280 Speaker 1: cross the event horizon, because when you cross the event horizon, 389 00:18:25,480 --> 00:18:28,080 Speaker 1: that circle that there's the rest of the universe is 390 00:18:28,119 --> 00:18:31,000 Speaker 1: now shrinking down to a tiny little dot. And once 391 00:18:31,000 --> 00:18:33,240 Speaker 1: you fall inside the event horizon, then the rest of 392 00:18:33,240 --> 00:18:36,840 Speaker 1: the universe is now exactly one tiny little point where 393 00:18:36,880 --> 00:18:39,360 Speaker 1: light from the universe can still reach you. Yeah, it's 394 00:18:39,359 --> 00:18:42,639 Speaker 1: a pretty trippy experience and pretty extreme and and actually, 395 00:18:42,680 --> 00:18:45,199 Speaker 1: if you want to know more about this, it's conveniently 396 00:18:45,200 --> 00:18:47,879 Speaker 1: a question we answer in our new book. Right Daniel 397 00:18:47,960 --> 00:18:50,760 Speaker 1: frequently ask questions about the universe. That's right, This is 398 00:18:50,800 --> 00:18:53,320 Speaker 1: a frequently asked question. What would it be like to 399 00:18:53,400 --> 00:18:55,639 Speaker 1: fall into a black hole, and the book is a 400 00:18:55,640 --> 00:18:59,080 Speaker 1: lot of fun. It's out on November two one. You 401 00:18:59,080 --> 00:19:00,840 Speaker 1: can check it out at you reverse f a q 402 00:19:01,080 --> 00:19:03,639 Speaker 1: dot com. It's filled with answers and a bunch of 403 00:19:03,680 --> 00:19:06,080 Speaker 1: really awesome cartoons at or he drew. They give you 404 00:19:06,160 --> 00:19:08,000 Speaker 1: a sense for what it would look like to fall 405 00:19:08,080 --> 00:19:10,560 Speaker 1: into a black hole. Yeah, order a copy for yourself, 406 00:19:10,600 --> 00:19:14,040 Speaker 1: for your nieces and nephews, uncles and best friends. But 407 00:19:14,200 --> 00:19:16,119 Speaker 1: we do sort of go into a lot of details 408 00:19:16,160 --> 00:19:18,400 Speaker 1: because there are a lot of details about going into 409 00:19:18,440 --> 00:19:20,240 Speaker 1: the black hole, and I'm not sure we can cover 410 00:19:20,280 --> 00:19:22,080 Speaker 1: all of them. So please check out the book if 411 00:19:22,080 --> 00:19:24,960 Speaker 1: you are actually that curious, because there are a lot 412 00:19:24,960 --> 00:19:27,600 Speaker 1: of complications, like not only does the black hole take 413 00:19:27,680 --> 00:19:29,680 Speaker 1: up your whole field of view, but also like it's 414 00:19:29,720 --> 00:19:32,879 Speaker 1: possible for you to get inside a black hole without 415 00:19:32,920 --> 00:19:36,439 Speaker 1: getting stretched into spaghetti. It sort of all depends on 416 00:19:36,480 --> 00:19:39,040 Speaker 1: these details about the mass of the black hole, right, 417 00:19:39,240 --> 00:19:41,879 Speaker 1: And that's right. So if you're interested that, dig into 418 00:19:41,920 --> 00:19:43,760 Speaker 1: that copy of that book and let us know if 419 00:19:43,800 --> 00:19:46,000 Speaker 1: you have any follow up questions. All right, So, the 420 00:19:46,000 --> 00:19:49,440 Speaker 1: basic answers for Levi is you can calculate the mess 421 00:19:49,440 --> 00:19:51,240 Speaker 1: with a black hole by how the things around it 422 00:19:51,280 --> 00:19:53,720 Speaker 1: are moving. And also when you need to turn around 423 00:19:53,760 --> 00:19:56,080 Speaker 1: when you visit a black hole, before you visit a 424 00:19:56,080 --> 00:19:59,159 Speaker 1: black hole, when you need to turn around right exactly 425 00:19:59,200 --> 00:20:03,160 Speaker 1: before you start arching Airbnb for black hole opportunities. Yeah, 426 00:20:03,200 --> 00:20:07,800 Speaker 1: don't believe those pictures. They distort the space inside of 427 00:20:07,840 --> 00:20:10,800 Speaker 1: the airbnbs. All right, let's get into our two other 428 00:20:11,040 --> 00:20:13,800 Speaker 1: listener questions about black holes. One of them is about 429 00:20:13,880 --> 00:20:17,160 Speaker 1: mini black holes and the other one is about dark matter. 430 00:20:17,920 --> 00:20:32,840 Speaker 1: But first, let's take a quick break. All right, we're 431 00:20:32,880 --> 00:20:37,560 Speaker 1: answering questions about black holes from listeners, and you get 432 00:20:37,560 --> 00:20:39,760 Speaker 1: a lot of questions about black holes. I do. I 433 00:20:39,840 --> 00:20:41,679 Speaker 1: have a lot of questions for about black holes. I 434 00:20:41,760 --> 00:20:43,760 Speaker 1: read a lot about black holes, and we get lots 435 00:20:43,760 --> 00:20:47,040 Speaker 1: of questions from the listeners about black holes because everybody 436 00:20:47,080 --> 00:20:49,159 Speaker 1: wants to know what's going on. I see, And what 437 00:20:49,240 --> 00:20:51,480 Speaker 1: proportion of the questions you get do you actually know 438 00:20:51,560 --> 00:20:53,959 Speaker 1: the answer? We'll have a wonderful backup, which is if 439 00:20:53,960 --> 00:20:55,600 Speaker 1: I don't know the answer, I just send them a 440 00:20:55,640 --> 00:20:58,360 Speaker 1: link to our book we have no idea and say 441 00:20:58,480 --> 00:21:00,520 Speaker 1: that's the answer. Go buy a copy of the book. 442 00:21:01,240 --> 00:21:04,240 Speaker 1: Oh boy, you're plugging away today. I'm plugging away. But 443 00:21:04,280 --> 00:21:07,159 Speaker 1: also I think people like to hear that the question 444 00:21:07,200 --> 00:21:09,200 Speaker 1: they've asked is not one that has an answer. Of 445 00:21:09,280 --> 00:21:11,440 Speaker 1: course people would like to know the answer, but it's 446 00:21:11,440 --> 00:21:14,560 Speaker 1: also satisfying to feel like, Oh, I'm at the forefront 447 00:21:14,600 --> 00:21:17,960 Speaker 1: of human knowledge. I have questions, just like Kip Thorne 448 00:21:18,000 --> 00:21:20,840 Speaker 1: has questions, or just like very Barish has questions. These 449 00:21:20,880 --> 00:21:24,159 Speaker 1: Nobel Prize winners who also don't understand what's going on 450 00:21:24,200 --> 00:21:26,760 Speaker 1: inside a black hole. Welcome to the club, the curious 451 00:21:26,760 --> 00:21:29,879 Speaker 1: about black holes club. All right, so our second question 452 00:21:30,000 --> 00:21:32,160 Speaker 1: is from Tim and he has a question about mini 453 00:21:32,200 --> 00:21:36,760 Speaker 1: black holes. Hello, Daniel, Joaii, and Katie. I've got to 454 00:21:36,880 --> 00:21:39,520 Speaker 1: question about many black holes. If you were to have 455 00:21:39,600 --> 00:21:43,200 Speaker 1: some super large head dron collider and create miniature black 456 00:21:43,240 --> 00:21:47,639 Speaker 1: holes that immediately disappear with Hawking radiation, how would you 457 00:21:47,640 --> 00:21:51,639 Speaker 1: detect that Hawking radiation? And what would you learn since 458 00:21:51,800 --> 00:21:55,600 Speaker 1: all the information other than the mass of the black 459 00:21:55,600 --> 00:22:01,280 Speaker 1: hole is essentially destroyed? Curious about the answer? Shoots? Alright, 460 00:22:01,560 --> 00:22:04,760 Speaker 1: awesome question here. There's a lot in this question. There's 461 00:22:04,960 --> 00:22:07,359 Speaker 1: the idea of MENI black holes, there's the idea of 462 00:22:07,359 --> 00:22:11,679 Speaker 1: Hawking radiation. And he asked about quantum information. I know 463 00:22:11,880 --> 00:22:15,040 Speaker 1: so many good questions and so many fun opportunities to 464 00:22:15,119 --> 00:22:18,440 Speaker 1: learn about black holes by creating them a particle colliders. 465 00:22:18,600 --> 00:22:20,600 Speaker 1: All right, so let's dig into it, Daniel, What is 466 00:22:20,640 --> 00:22:22,680 Speaker 1: a medi black hole? I guess it's just a small 467 00:22:22,720 --> 00:22:24,920 Speaker 1: black hole. Are there's possible? How do you make them? Yeah? 468 00:22:24,920 --> 00:22:27,680 Speaker 1: Black holes can come in almost any size. There is 469 00:22:27,720 --> 00:22:30,360 Speaker 1: an absolute minimum size to a black hole, but it's 470 00:22:30,400 --> 00:22:32,919 Speaker 1: pretty small. You can make a black hole that's the 471 00:22:32,960 --> 00:22:34,960 Speaker 1: size of the galaxy. You can make a black hole 472 00:22:35,200 --> 00:22:37,800 Speaker 1: that's like, you know, the size of a particle. Almost 473 00:22:37,920 --> 00:22:40,960 Speaker 1: The crucial thing is not the mass, it's the density. 474 00:22:41,240 --> 00:22:44,200 Speaker 1: If you compact enough stuff into a small enough space, 475 00:22:44,480 --> 00:22:47,280 Speaker 1: then you can create a black hole. Is this combination 476 00:22:47,320 --> 00:22:49,760 Speaker 1: of mass and radius. You know, for example, if you 477 00:22:49,800 --> 00:22:52,240 Speaker 1: took the Earth, you could compact it into a peanut 478 00:22:52,320 --> 00:22:54,440 Speaker 1: and that would be a black hole. So the mass 479 00:22:54,440 --> 00:22:56,400 Speaker 1: of the Earth is enough to make a black hole, 480 00:22:56,520 --> 00:22:58,640 Speaker 1: is just not dense enough. And so you can make 481 00:22:58,720 --> 00:23:01,879 Speaker 1: many black holes by poor enough energy or enough mass 482 00:23:01,920 --> 00:23:04,280 Speaker 1: into a small enough space. And that's what you do 483 00:23:04,320 --> 00:23:07,320 Speaker 1: at the large Hadron collider. Right, you think you're making 484 00:23:07,320 --> 00:23:09,760 Speaker 1: mini black holes, or you know you're making mini black holes. 485 00:23:09,920 --> 00:23:12,360 Speaker 1: We hope we're making many black holes. We haven't yet 486 00:23:12,400 --> 00:23:14,720 Speaker 1: seen any. But that is exactly what we do at 487 00:23:14,720 --> 00:23:17,359 Speaker 1: the Hadron Collider and it Aeron Collider, is that we 488 00:23:17,400 --> 00:23:20,000 Speaker 1: pour a lot of energy into a very small space 489 00:23:20,320 --> 00:23:22,679 Speaker 1: and we let the universe decide what comes out. We 490 00:23:22,720 --> 00:23:26,119 Speaker 1: take advantage of the quantum mechanical nature, the probabilistic nature 491 00:23:26,240 --> 00:23:28,359 Speaker 1: of the rules of physics that say, if you have 492 00:23:28,440 --> 00:23:31,000 Speaker 1: a little ball of energy there, it can basically turn 493 00:23:31,040 --> 00:23:33,480 Speaker 1: into anything. It might turn into some new particle you 494 00:23:33,480 --> 00:23:36,560 Speaker 1: haven't seen before, it might turn into a black hole, right, 495 00:23:36,600 --> 00:23:38,960 Speaker 1: And so you sometimes you get enough energy pack into 496 00:23:39,000 --> 00:23:41,879 Speaker 1: such a small space that you make a mini tiny 497 00:23:41,920 --> 00:23:44,719 Speaker 1: black hole about the size of like a particle. And 498 00:23:44,760 --> 00:23:47,680 Speaker 1: so those are actually black holes, just like the ones 499 00:23:47,720 --> 00:23:50,040 Speaker 1: at the center of the galaxies. They're just really really small, 500 00:23:50,400 --> 00:23:52,720 Speaker 1: and something special happens to them, right. They don't last 501 00:23:52,800 --> 00:23:54,560 Speaker 1: very long, that's right. And so to be clear, we 502 00:23:54,640 --> 00:23:57,280 Speaker 1: have not to our knowledge made any of these black holes. 503 00:23:57,320 --> 00:24:00,399 Speaker 1: We have not seen any. It's hypothetical to fear radical 504 00:24:00,440 --> 00:24:03,840 Speaker 1: idea that perhaps it's possible to make these black holes 505 00:24:04,040 --> 00:24:06,720 Speaker 1: by colliding particles together. And so we are looking for them, 506 00:24:06,760 --> 00:24:08,639 Speaker 1: and the thing you have to understand about many black 507 00:24:08,640 --> 00:24:11,000 Speaker 1: holes is that they don't last very long. Like big 508 00:24:11,040 --> 00:24:13,439 Speaker 1: black holes can last for billions of years as they 509 00:24:13,520 --> 00:24:16,719 Speaker 1: keep eating stuff. But all black holes emit radiation. They 510 00:24:16,760 --> 00:24:20,160 Speaker 1: don't actually keep all of their information is inside. They 511 00:24:20,240 --> 00:24:22,920 Speaker 1: leak a little bit of mass all the time. It's 512 00:24:22,920 --> 00:24:26,359 Speaker 1: called hawking radiation. And this happens faster if you're a 513 00:24:26,400 --> 00:24:29,240 Speaker 1: small black hole. So a big black hole hardly emits 514 00:24:29,280 --> 00:24:31,680 Speaker 1: any hawking radiation. It can last for a long time. 515 00:24:32,000 --> 00:24:35,880 Speaker 1: A little black hole will very rapidly evaporate by giving 516 00:24:35,920 --> 00:24:38,120 Speaker 1: away all of its mass in terms of hawking radiation. 517 00:24:38,200 --> 00:24:41,639 Speaker 1: So the smaller the black hole is, the quicker it disappears, 518 00:24:41,680 --> 00:24:43,800 Speaker 1: which is actually good because you want your black holes 519 00:24:43,840 --> 00:24:46,800 Speaker 1: to evaporate rather than growing and gobbling up the earth. 520 00:24:46,920 --> 00:24:49,760 Speaker 1: All right, So then the tiny black holes evaporate quickly. 521 00:24:49,800 --> 00:24:51,840 Speaker 1: And the question I guess is can you detect that 522 00:24:51,880 --> 00:24:54,440 Speaker 1: hawking radiation? And what would you learn from it? Yes, 523 00:24:54,480 --> 00:24:56,320 Speaker 1: So these black holes, if you made them, they would 524 00:24:56,320 --> 00:25:00,159 Speaker 1: basically explode almost instantaneously. The kind we're talking about making 525 00:25:00,200 --> 00:25:02,399 Speaker 1: it the large Hadron collider would last like ten to 526 00:25:02,440 --> 00:25:05,480 Speaker 1: the minus twenty seven seconds, and they would just admit 527 00:25:05,480 --> 00:25:08,240 Speaker 1: a bunch of hawking radiation. But what is that hawking radiation? 528 00:25:08,320 --> 00:25:10,200 Speaker 1: And how would you see it? The cool thing about 529 00:25:10,240 --> 00:25:13,560 Speaker 1: black holes is that they couple gravitationally, right, They're connected 530 00:25:13,560 --> 00:25:15,920 Speaker 1: to everything that has mass. They don't care about things 531 00:25:16,000 --> 00:25:19,040 Speaker 1: electric charge or strong charge or weak charge, so there's 532 00:25:19,080 --> 00:25:21,879 Speaker 1: sort of democratic. They turn into like all kinds of 533 00:25:21,920 --> 00:25:25,119 Speaker 1: particles with basically equal probability, And so that means that 534 00:25:25,119 --> 00:25:27,760 Speaker 1: what you would see is just a huge spray of 535 00:25:27,760 --> 00:25:30,720 Speaker 1: a bunch of different particles, like a huge explosion at 536 00:25:30,720 --> 00:25:33,240 Speaker 1: the center of your detector, with a lot more energy 537 00:25:33,280 --> 00:25:36,560 Speaker 1: than you would typically seem I see, but you're eagually 538 00:25:36,600 --> 00:25:38,879 Speaker 1: like to see like an electron or a proton or 539 00:25:39,320 --> 00:25:42,200 Speaker 1: men kind of right. I mean, depending on how much 540 00:25:42,440 --> 00:25:45,000 Speaker 1: energy they have, they might be more probable, but there's 541 00:25:45,000 --> 00:25:48,119 Speaker 1: no constraint about what particular particles you'll see, that's what 542 00:25:48,160 --> 00:25:50,800 Speaker 1: you're saying. Yeah, And because the particles that feel the 543 00:25:50,880 --> 00:25:54,880 Speaker 1: strong force, like quarks and gluons, have so many more varieties, 544 00:25:54,880 --> 00:25:58,160 Speaker 1: because for example, for the upcork, there's the red upcork, 545 00:25:58,240 --> 00:26:00,920 Speaker 1: the green upcork, and the blue upcork, where the electron 546 00:26:01,119 --> 00:26:03,200 Speaker 1: doesn't feel that, and so it only has one version. 547 00:26:03,400 --> 00:26:06,320 Speaker 1: That means there are more versions of quirks and gluons, 548 00:26:06,359 --> 00:26:08,840 Speaker 1: So you're more likely going to get quarks and gluons 549 00:26:08,880 --> 00:26:12,159 Speaker 1: than electrons and muans, just because there are more of those, 550 00:26:12,480 --> 00:26:15,160 Speaker 1: and black holes are democratic, So most likely what you're 551 00:26:15,160 --> 00:26:17,880 Speaker 1: gonna see is a big spray of quarks and gluons 552 00:26:17,920 --> 00:26:20,000 Speaker 1: that fly out, and quirks and gluons. We don't see 553 00:26:20,000 --> 00:26:23,480 Speaker 1: those directly because quirks and gluons can't be by themselves, 554 00:26:23,520 --> 00:26:26,920 Speaker 1: so instead each one turns into its own stream of particles. 555 00:26:26,920 --> 00:26:28,600 Speaker 1: So what does a black hole look like? In our 556 00:26:28,640 --> 00:26:32,080 Speaker 1: detector at CERN It looks like seven or ten streams 557 00:26:32,080 --> 00:26:34,800 Speaker 1: of particles all coming out of the center of the collision. Well, 558 00:26:34,840 --> 00:26:37,400 Speaker 1: I think the question that Tim had was like, could 559 00:26:37,480 --> 00:26:39,719 Speaker 1: you learn or would you learn anything from that stream 560 00:26:39,800 --> 00:26:42,440 Speaker 1: of particles? And it sort of seems like you wouldn't 561 00:26:42,440 --> 00:26:45,920 Speaker 1: write because it just be a random spray of particles, right, Yeah, 562 00:26:45,920 --> 00:26:48,080 Speaker 1: And this is a subtle point here, because you can't 563 00:26:48,080 --> 00:26:50,399 Speaker 1: look at an individual collision that has like ten of 564 00:26:50,400 --> 00:26:52,880 Speaker 1: these sprays of particles and say that's a smoking gun 565 00:26:52,920 --> 00:26:54,960 Speaker 1: signature of a black hole, because there are other ways 566 00:26:55,000 --> 00:26:57,439 Speaker 1: for that to happen. Sometimes two protons collide and you 567 00:26:57,520 --> 00:27:00,399 Speaker 1: do get ten quarks flying out, which makes ten of 568 00:27:00,440 --> 00:27:02,840 Speaker 1: these streams of particles. So that does happen. So we 569 00:27:02,880 --> 00:27:05,679 Speaker 1: can't specifically say this was a black hole, that was 570 00:27:05,720 --> 00:27:07,200 Speaker 1: a black hole. All we can do is say, look, 571 00:27:07,240 --> 00:27:09,800 Speaker 1: we see more of these collisions that lead to ten 572 00:27:09,960 --> 00:27:13,320 Speaker 1: or twelve sprays of particles than we expected from non 573 00:27:13,359 --> 00:27:16,800 Speaker 1: black hole sources. So we can like statistically say we 574 00:27:16,840 --> 00:27:19,639 Speaker 1: think we're making black holes because we see more of 575 00:27:19,680 --> 00:27:22,280 Speaker 1: these weird kind of events than we can explain otherwise. 576 00:27:22,359 --> 00:27:24,600 Speaker 1: And this weird kind of event is just what we 577 00:27:24,640 --> 00:27:27,480 Speaker 1: expected to see from black holes. So we can't definitively 578 00:27:27,520 --> 00:27:30,520 Speaker 1: say a black hole is created on Tuesday at four pm, 579 00:27:30,680 --> 00:27:32,920 Speaker 1: but we can't say over the last year, we think 580 00:27:32,960 --> 00:27:34,520 Speaker 1: we made ten of them. Well, I see, you can't 581 00:27:34,520 --> 00:27:37,000 Speaker 1: study like a particular mini black hole. You can study 582 00:27:37,080 --> 00:27:39,960 Speaker 1: kind of like a statistically what's going on in your collider. 583 00:27:40,080 --> 00:27:42,600 Speaker 1: But I think Tim was sort of making the connection 584 00:27:42,840 --> 00:27:45,399 Speaker 1: to this idea that we've talked about before, which is 585 00:27:45,400 --> 00:27:48,880 Speaker 1: an inside of a black hole, quantum information is destroyed. 586 00:27:49,280 --> 00:27:52,480 Speaker 1: So does that mean that when a mini black hole evaporates, 587 00:27:53,040 --> 00:27:56,439 Speaker 1: there's no information in the Hawking radiation. Yeah, this is 588 00:27:56,440 --> 00:27:58,919 Speaker 1: not something that we understand because we think that quantum 589 00:27:58,960 --> 00:28:02,080 Speaker 1: information can't be stroids, and so we wonder if somehow 590 00:28:02,119 --> 00:28:05,600 Speaker 1: that hockey information does have encoded in it the quantum 591 00:28:05,600 --> 00:28:08,119 Speaker 1: information that went into the black hole. And we had 592 00:28:08,160 --> 00:28:10,640 Speaker 1: recently a fun podcast episode where we talked about people 593 00:28:10,640 --> 00:28:13,160 Speaker 1: who recently made a breakthrough about how this might work 594 00:28:13,359 --> 00:28:16,200 Speaker 1: as super fascinating, but it's not something we understand very well. 595 00:28:16,240 --> 00:28:18,480 Speaker 1: But the information is being destroyed in a black hole 596 00:28:18,760 --> 00:28:20,880 Speaker 1: is just about the particles that went into it, which 597 00:28:20,880 --> 00:28:23,320 Speaker 1: is like the two protons you smashed together. So you 598 00:28:23,359 --> 00:28:26,399 Speaker 1: don't really care that much about that quantum information. It's 599 00:28:26,440 --> 00:28:28,640 Speaker 1: not like useful or interesting. But if you do make 600 00:28:28,640 --> 00:28:31,359 Speaker 1: black holes, you can learn something much more interesting about 601 00:28:31,359 --> 00:28:34,440 Speaker 1: the universe. You can gain like contextual information because you 602 00:28:34,480 --> 00:28:37,480 Speaker 1: can learn something about quantum gravity. If we make black 603 00:28:37,520 --> 00:28:40,400 Speaker 1: holes with a large Hadron collider, it means that gravity 604 00:28:40,520 --> 00:28:43,800 Speaker 1: is much stronger at very short distances than it is 605 00:28:43,840 --> 00:28:46,720 Speaker 1: at long distances. Something weird and different is going on 606 00:28:47,000 --> 00:28:50,560 Speaker 1: when two particles get really close together, their gravity gets different, 607 00:28:50,880 --> 00:28:53,760 Speaker 1: and that's a clue about maybe the whole nature of space, 608 00:28:53,800 --> 00:28:57,200 Speaker 1: about how many dimensions there are two space itself. Well, 609 00:28:57,320 --> 00:28:59,160 Speaker 1: what do you mean, Like you would shoot things together, 610 00:28:59,320 --> 00:29:03,120 Speaker 1: create many black goals, and then you would see how 611 00:29:03,200 --> 00:29:05,280 Speaker 1: it interacts with the things around it. Like, can you 612 00:29:05,320 --> 00:29:08,000 Speaker 1: actually get a sense of, you know, what happens as 613 00:29:08,000 --> 00:29:10,000 Speaker 1: you get that close to mini black holes or is 614 00:29:10,040 --> 00:29:12,680 Speaker 1: it maybe hidden in the fact that you do or 615 00:29:12,720 --> 00:29:14,720 Speaker 1: do not get mini black holes. Yeah, it's the fact 616 00:29:14,720 --> 00:29:17,560 Speaker 1: that you make black holes, and also their typical energy 617 00:29:17,800 --> 00:29:20,600 Speaker 1: tells you something about how they are made. You can't 618 00:29:20,600 --> 00:29:23,160 Speaker 1: study an individual black hole or like put things near 619 00:29:23,200 --> 00:29:25,120 Speaker 1: it or anything like that. But one thing we are 620 00:29:25,160 --> 00:29:28,120 Speaker 1: really curious about is why gravity seems to be so weak. 621 00:29:28,160 --> 00:29:30,400 Speaker 1: You know, gravity is so much weaker than all of 622 00:29:30,400 --> 00:29:33,200 Speaker 1: the other forces. Like we say, often you can defeat 623 00:29:33,240 --> 00:29:36,000 Speaker 1: the entire gravity the Earth by using a simple kitchen 624 00:29:36,040 --> 00:29:38,640 Speaker 1: magnet to pull on a screw, for example. So why 625 00:29:38,720 --> 00:29:42,040 Speaker 1: is gravity so weak? It's not something we understand. One 626 00:29:42,120 --> 00:29:45,840 Speaker 1: possible explanation is that maybe gravity is so weak because 627 00:29:45,960 --> 00:29:49,520 Speaker 1: it's leaking out. It's like getting diluted. Because there are 628 00:29:49,640 --> 00:29:52,240 Speaker 1: other ways that you can move through space other than 629 00:29:52,280 --> 00:29:55,719 Speaker 1: the three were familiar with. So these are called extra dimensions, 630 00:29:55,760 --> 00:29:59,200 Speaker 1: Like maybe space doesn't have just three dimensions, maybe it 631 00:29:59,240 --> 00:30:03,920 Speaker 1: has eleven or twenty six, but only gravity can feel those, 632 00:30:04,000 --> 00:30:06,240 Speaker 1: and so when you're far away from something, you're not 633 00:30:06,320 --> 00:30:09,200 Speaker 1: really feeling it's true gravity because most of it's leaked 634 00:30:09,240 --> 00:30:11,840 Speaker 1: out into these other dimensions. But these other dimensions might 635 00:30:11,840 --> 00:30:14,280 Speaker 1: be really really small and compact, so if you get 636 00:30:14,320 --> 00:30:17,040 Speaker 1: really close to something, you might feel it's like true 637 00:30:17,040 --> 00:30:19,440 Speaker 1: strength of its gravity. So the idea is if you 638 00:30:19,480 --> 00:30:22,360 Speaker 1: smash two protons together and you bring them really close 639 00:30:22,400 --> 00:30:25,080 Speaker 1: together with enough energy, then they might feel that strong 640 00:30:25,120 --> 00:30:27,840 Speaker 1: gravity enough to make a black hole. So the fact 641 00:30:27,880 --> 00:30:29,760 Speaker 1: that you made the black hole would tap you off 642 00:30:30,000 --> 00:30:33,400 Speaker 1: that gravity is getting strong at short distances and maybe 643 00:30:33,440 --> 00:30:36,840 Speaker 1: reveal something about the existence of those other dimensions of 644 00:30:36,840 --> 00:30:38,920 Speaker 1: space and time. So you're saying that if you do 645 00:30:38,960 --> 00:30:41,320 Speaker 1: make black holes at the large Harding glider, then maybe 646 00:30:41,440 --> 00:30:45,000 Speaker 1: that points to the existence of extra dimensions. Yes, exactly, 647 00:30:45,040 --> 00:30:47,360 Speaker 1: so we can't learn that much from one black hole, 648 00:30:47,640 --> 00:30:49,920 Speaker 1: but if we can prove that we have been making them, 649 00:30:50,000 --> 00:30:52,640 Speaker 1: then that suggests that there must be extra dimensions space 650 00:30:52,640 --> 00:30:55,680 Speaker 1: and time, and the pattern in which they appear, like 651 00:30:55,720 --> 00:30:58,640 Speaker 1: the energy that they come with and how often we 652 00:30:58,720 --> 00:31:00,720 Speaker 1: make them, can give us a clue to like how 653 00:31:00,760 --> 00:31:04,120 Speaker 1: many dimensions are there and what radius do they have, 654 00:31:04,160 --> 00:31:06,640 Speaker 1: because these aren't dimensions like the ones we're familiar with, 655 00:31:06,720 --> 00:31:08,719 Speaker 1: like x, y, and z that we move around in. 656 00:31:08,840 --> 00:31:11,480 Speaker 1: These are like a little looped dimensions. They're like moving 657 00:31:11,520 --> 00:31:14,520 Speaker 1: a little circle, or they are only like a centimeter wide. 658 00:31:14,760 --> 00:31:17,560 Speaker 1: They're really weird and strange dimensions. But lots of theories 659 00:31:17,560 --> 00:31:21,320 Speaker 1: of physics actually insist on having more dimensions, like string theory. Yeah, 660 00:31:21,360 --> 00:31:23,840 Speaker 1: and conveniently that's another topic we cover in our book. 661 00:31:24,600 --> 00:31:26,520 Speaker 1: But it sort of sounds like the answer for tim 662 00:31:26,520 --> 00:31:29,760 Speaker 1: here is that we haven't detected any mini black holes 663 00:31:29,840 --> 00:31:32,400 Speaker 1: in you're in the colliders, but if you if you 664 00:31:32,440 --> 00:31:35,360 Speaker 1: do create them, hey, you would see this big shower 665 00:31:35,360 --> 00:31:39,320 Speaker 1: of sort of random particles, maybe mostly quirks, and be 666 00:31:39,520 --> 00:31:42,320 Speaker 1: would point to the existence of extra dimensions. That's right, 667 00:31:42,360 --> 00:31:45,960 Speaker 1: that's one explanation. There are other theories that also predict 668 00:31:45,960 --> 00:31:48,080 Speaker 1: the creation of black holes, and so if we did 669 00:31:48,120 --> 00:31:50,560 Speaker 1: see them, the theories would go crazy coming up with 670 00:31:50,600 --> 00:31:52,920 Speaker 1: new ideas to explain our data. It would be very 671 00:31:53,040 --> 00:31:55,080 Speaker 1: very exciting. And for those of you nervous about the 672 00:31:55,080 --> 00:31:57,520 Speaker 1: safety aspect of this, don't worry. We've done all the 673 00:31:57,560 --> 00:32:00,200 Speaker 1: calculations and we're confident we can't make black hole is 674 00:32:00,240 --> 00:32:05,080 Speaker 1: big enough to eat. That's good to know, always reassuring 675 00:32:05,280 --> 00:32:08,239 Speaker 1: that you've done the calculations and that you never make mistakes. Right, 676 00:32:08,280 --> 00:32:10,680 Speaker 1: that's right. We've never ever made a mistake that destroyed 677 00:32:10,720 --> 00:32:13,440 Speaker 1: the Earth. Right, that's a pretty good track record. Yeah, yeah, 678 00:32:13,440 --> 00:32:16,240 Speaker 1: so far zero for zero. All right, well, let's get 679 00:32:16,240 --> 00:32:19,120 Speaker 1: into our last question about black holes from a listener, 680 00:32:19,240 --> 00:32:22,000 Speaker 1: and this one has to do with dark matter. But 681 00:32:22,040 --> 00:32:37,000 Speaker 1: first let's take another quick break. All right, we're answering 682 00:32:37,080 --> 00:32:40,440 Speaker 1: questions from listeners about black holes because they're so cool 683 00:32:40,520 --> 00:32:44,120 Speaker 1: and mysterious and dark. And our last question comes from Jue, 684 00:32:44,280 --> 00:32:47,960 Speaker 1: who has a question about whether black holes can explain 685 00:32:48,720 --> 00:32:51,680 Speaker 1: a little bit of missing mass. If there's missing gravity 686 00:32:51,720 --> 00:32:54,840 Speaker 1: in the galaxy, why can't we attribute it too the 687 00:32:55,080 --> 00:32:57,880 Speaker 1: black hole in the center of it since we don't 688 00:32:57,880 --> 00:33:00,640 Speaker 1: know it's mass. M interesting question, and first of all, 689 00:33:00,800 --> 00:33:03,400 Speaker 1: we're missing mass, like did we misplace some mass in 690 00:33:03,400 --> 00:33:06,240 Speaker 1: the galaxy? Oops? I thought you were going to bring 691 00:33:06,240 --> 00:33:08,480 Speaker 1: it home? Where is it that the galaxy going a 692 00:33:08,560 --> 00:33:11,280 Speaker 1: quick diet or something? In a go keto? You look 693 00:33:11,320 --> 00:33:13,720 Speaker 1: in great these days, milky Way. Maybe it's like only 694 00:33:13,760 --> 00:33:16,520 Speaker 1: two percent milky way or like low fat milky way 695 00:33:16,920 --> 00:33:20,000 Speaker 1: skin milky way. All right, so there is some missing 696 00:33:20,040 --> 00:33:22,480 Speaker 1: mass in the galaxy, right, I know this one. It's like, 697 00:33:22,520 --> 00:33:24,760 Speaker 1: if you measure how the stars in the galaxy are 698 00:33:24,800 --> 00:33:29,240 Speaker 1: spinning around, they are spinning around faster than they would 699 00:33:29,320 --> 00:33:32,560 Speaker 1: be if there was only stars and planets in the galaxy. Right, 700 00:33:32,560 --> 00:33:36,400 Speaker 1: there's something else missing from the mass of how we 701 00:33:36,440 --> 00:33:39,480 Speaker 1: see the galaxy spinning exactly, just like we were talking about. 702 00:33:39,760 --> 00:33:42,040 Speaker 1: You can deduce the mass that the Sun has to 703 00:33:42,120 --> 00:33:44,560 Speaker 1: be to explain the Earth's motion. You can do the 704 00:33:44,600 --> 00:33:47,200 Speaker 1: same thing with the whole galaxy. Measure the motion of 705 00:33:47,240 --> 00:33:50,240 Speaker 1: the stars and from that deduce the mass of all 706 00:33:50,280 --> 00:33:52,440 Speaker 1: the stuff that has to be pulling on those stars 707 00:33:52,480 --> 00:33:55,080 Speaker 1: to keep them moving in a circle. It's exactly the 708 00:33:55,120 --> 00:33:58,200 Speaker 1: same strategy, right, And this is kind of how people 709 00:33:58,200 --> 00:34:00,960 Speaker 1: first started thinking about dark matter, which is that they 710 00:34:01,000 --> 00:34:04,320 Speaker 1: saw that the galaxies were spinning faster than they would 711 00:34:04,560 --> 00:34:08,120 Speaker 1: be if if the stars were to stay in the galaxy, 712 00:34:08,320 --> 00:34:11,920 Speaker 1: and so they hypothesized like, hey, maybe there's some invisible mass. 713 00:34:12,160 --> 00:34:14,239 Speaker 1: We'll call it dark matter, and that's what's keeping all 714 00:34:14,280 --> 00:34:16,680 Speaker 1: the stars in the galaxy I usually think about it 715 00:34:16,760 --> 00:34:19,520 Speaker 1: the other direction. They measure the velocity of the stars, 716 00:34:19,560 --> 00:34:21,560 Speaker 1: and then they asked, how much gravity do you need 717 00:34:21,600 --> 00:34:24,239 Speaker 1: to explain that motion to keep the stars from flying up? 718 00:34:24,640 --> 00:34:26,919 Speaker 1: And then they couldn't find that much mass. They looked 719 00:34:26,960 --> 00:34:29,120 Speaker 1: at all the stars and all the dust and all 720 00:34:29,120 --> 00:34:31,680 Speaker 1: the things they could see, and it just didn't add up. 721 00:34:31,719 --> 00:34:34,920 Speaker 1: It wasn't even close. So that was a big puzzle 722 00:34:34,960 --> 00:34:39,120 Speaker 1: for decades, right, And so the idea of a lot 723 00:34:39,160 --> 00:34:42,359 Speaker 1: of invisible mass out there in the universe is kind 724 00:34:42,360 --> 00:34:43,759 Speaker 1: of crazy. So a lot of people are like, are 725 00:34:43,760 --> 00:34:46,200 Speaker 1: you sure that sounds crazy? How do you know that 726 00:34:46,719 --> 00:34:49,320 Speaker 1: maybe the black hole at the center of the galaxy 727 00:34:49,400 --> 00:34:51,640 Speaker 1: isn't just heavier than you think it is. Maybe that 728 00:34:51,680 --> 00:34:54,680 Speaker 1: would explain why the stars are not flying off into space. Yeah, 729 00:34:54,719 --> 00:34:57,799 Speaker 1: it's a great question because it points to like our uncertainty, 730 00:34:57,880 --> 00:35:00,000 Speaker 1: like how do you know how massive those stars are? 731 00:35:00,040 --> 00:35:01,840 Speaker 1: And how do you know the other things in the galaxy? 732 00:35:01,920 --> 00:35:03,759 Speaker 1: How well do you know their mass? And so it's 733 00:35:03,800 --> 00:35:06,160 Speaker 1: just like pointing at you know, other places we could 734 00:35:06,200 --> 00:35:09,239 Speaker 1: be making mistakes, which is a great scientific exercise, like 735 00:35:09,360 --> 00:35:11,520 Speaker 1: to go back and think, maybe we just missestimated the 736 00:35:11,600 --> 00:35:14,359 Speaker 1: number of stars, or maybe we missestimated their mass, or 737 00:35:14,480 --> 00:35:17,040 Speaker 1: maybe it's all hiding at the center of the galaxy 738 00:35:17,120 --> 00:35:19,719 Speaker 1: inside that black hole. Yeah, so the question is like, 739 00:35:19,800 --> 00:35:22,040 Speaker 1: could a bigger black hole at the center of the 740 00:35:22,040 --> 00:35:26,080 Speaker 1: galaxy explain how all the stars are moving around the 741 00:35:26,120 --> 00:35:28,800 Speaker 1: galaxy or does it have to be something like dark matter. 742 00:35:28,960 --> 00:35:31,560 Speaker 1: So there's sort of three answers, two knows, and then 743 00:35:31,760 --> 00:35:35,040 Speaker 1: maybe yes. So the first know is that we actually 744 00:35:35,080 --> 00:35:37,319 Speaker 1: kind of do know the mass of the black hole 745 00:35:37,360 --> 00:35:39,480 Speaker 1: at the center of the galaxy. It's not just some 746 00:35:39,719 --> 00:35:42,359 Speaker 1: huge cosmic noob that we can turn up and down 747 00:35:42,400 --> 00:35:44,480 Speaker 1: and say nobody knows, So we can just set it 748 00:35:44,520 --> 00:35:47,080 Speaker 1: to anything. As we talked about just a few minutes ago. 749 00:35:47,320 --> 00:35:49,520 Speaker 1: We can measure the mass of black holes by looking 750 00:35:49,840 --> 00:35:52,120 Speaker 1: at the movement of stars near it. And the one 751 00:35:52,239 --> 00:35:54,800 Speaker 1: near the center of our Milky Way is actually super 752 00:35:54,840 --> 00:35:58,040 Speaker 1: awesome because there's a star that gets really really close 753 00:35:58,080 --> 00:35:59,799 Speaker 1: to it. It whizz is right by, It ends up 754 00:35:59,800 --> 00:36:02,640 Speaker 1: going super fast and allows us to make a pretty 755 00:36:02,640 --> 00:36:04,960 Speaker 1: precise measurement of the mass of the black hole at 756 00:36:04,960 --> 00:36:06,960 Speaker 1: the center of the Milky Way. I see, so there 757 00:36:07,080 --> 00:36:09,759 Speaker 1: isn't like a mysterious black hole at the center of 758 00:36:09,760 --> 00:36:12,399 Speaker 1: the galaxy. There's one that we can measure. Yeah, we've 759 00:36:12,440 --> 00:36:14,640 Speaker 1: measured its mass pretty well, and there's a bunch of 760 00:36:14,680 --> 00:36:17,680 Speaker 1: stars moving around it. And this is this really awesome 761 00:36:17,800 --> 00:36:20,160 Speaker 1: video you should watch. It took like decades to make 762 00:36:20,520 --> 00:36:23,120 Speaker 1: of them observing the black hole and seeing the motion 763 00:36:23,160 --> 00:36:25,120 Speaker 1: of the stars around it, and you can watch it 764 00:36:25,120 --> 00:36:26,879 Speaker 1: in time lapse. You know, it took them twenty years, 765 00:36:26,920 --> 00:36:28,720 Speaker 1: but you can watch the whole thing in twenty seconds, 766 00:36:28,760 --> 00:36:31,960 Speaker 1: and you can see these stars moving around some obvious, 767 00:36:32,040 --> 00:36:35,960 Speaker 1: invisible object, like they're bending their path around what seems 768 00:36:35,960 --> 00:36:38,880 Speaker 1: to be nothing and therefore must be something. Right, And 769 00:36:38,920 --> 00:36:41,720 Speaker 1: it's pretty massive, I imagine, right, it's a pretty massive 770 00:36:41,719 --> 00:36:43,879 Speaker 1: black hole at the center of our galaxy. Yeah, it's 771 00:36:43,920 --> 00:36:47,520 Speaker 1: pretty heavy. It has four point one million times the 772 00:36:47,560 --> 00:36:50,560 Speaker 1: mass of our star, so it's pretty hefty. And I 773 00:36:50,640 --> 00:36:52,360 Speaker 1: just want to make a plug for U. C. L 774 00:36:52,400 --> 00:36:56,400 Speaker 1: a that won the Nobel Prize for these observations very recently. 775 00:36:56,600 --> 00:36:58,680 Speaker 1: So go check out that video. It's pretty cool, but 776 00:36:58,719 --> 00:37:01,640 Speaker 1: it's a pretty massive black hole hole, but it can't 777 00:37:01,680 --> 00:37:04,480 Speaker 1: explain all of the dark matter. Number one, because we 778 00:37:04,600 --> 00:37:06,759 Speaker 1: know it's mass, but number two also, it's in the 779 00:37:06,800 --> 00:37:10,040 Speaker 1: wrong place to explain the dark matter, right, Like, even 780 00:37:10,080 --> 00:37:12,439 Speaker 1: if we didn't know the mass of the black hole 781 00:37:12,480 --> 00:37:14,480 Speaker 1: at the center of the galaxy, Like, even if we 782 00:37:14,520 --> 00:37:17,000 Speaker 1: were wrong, one giant mass at the center of the 783 00:37:17,040 --> 00:37:19,800 Speaker 1: galaxy wouldn't explain how the all the stars are moving. 784 00:37:19,880 --> 00:37:22,799 Speaker 1: That's exactly right, because even if you increase the mass 785 00:37:22,800 --> 00:37:26,000 Speaker 1: of the black hole to account for all the missing stuff, 786 00:37:26,040 --> 00:37:29,000 Speaker 1: it wouldn't give you stars moving the way our stars 787 00:37:29,040 --> 00:37:30,880 Speaker 1: are moving. And that's because we can look at the 788 00:37:30,920 --> 00:37:33,400 Speaker 1: velocity of stars very close to the center of the 789 00:37:33,400 --> 00:37:36,560 Speaker 1: galaxy and the velocity stars further away from the center 790 00:37:36,560 --> 00:37:38,600 Speaker 1: of the galaxy. So what we need is dark matter 791 00:37:38,600 --> 00:37:41,840 Speaker 1: to explain all of those different velocities stars closer to 792 00:37:41,880 --> 00:37:44,400 Speaker 1: the center and stars further from the center, and every 793 00:37:44,400 --> 00:37:47,200 Speaker 1: star it's motion tells you about how much mass is 794 00:37:47,239 --> 00:37:49,880 Speaker 1: sort of in a sphere that's closer to the center 795 00:37:49,920 --> 00:37:52,400 Speaker 1: of the galaxy. Event it like, stars are not affected 796 00:37:52,440 --> 00:37:55,080 Speaker 1: by stuff that's further away from them, only by stuff 797 00:37:55,080 --> 00:37:57,680 Speaker 1: that's closer to them. So as you look at stars 798 00:37:57,719 --> 00:38:00,400 Speaker 1: as a function of their distance, you know is that 799 00:38:00,480 --> 00:38:02,880 Speaker 1: you need a distribution of mass that's sort of spread 800 00:38:02,960 --> 00:38:05,560 Speaker 1: out to the galaxy. If you only put a huge 801 00:38:05,560 --> 00:38:07,560 Speaker 1: blob of mass at the very center. It would make 802 00:38:07,560 --> 00:38:10,319 Speaker 1: the stars near the core of the galaxy move way 803 00:38:10,360 --> 00:38:13,719 Speaker 1: too fast, for example, right, right, because that's kind of 804 00:38:13,760 --> 00:38:16,640 Speaker 1: an interesting property of mass. It's like, you know, if 805 00:38:16,640 --> 00:38:18,799 Speaker 1: you're really far away from it, you might as well 806 00:38:18,960 --> 00:38:21,120 Speaker 1: treat it as a like a thought. But if you're 807 00:38:21,200 --> 00:38:23,759 Speaker 1: really close to it, then it does matter whether or 808 00:38:23,800 --> 00:38:26,200 Speaker 1: not it's like diffused in the little tiny ball in 809 00:38:26,200 --> 00:38:28,799 Speaker 1: the middle or in a giant cloud that actually there 810 00:38:28,840 --> 00:38:31,600 Speaker 1: is actually sort of engulfs you. Right, Yeah, if you're 811 00:38:31,680 --> 00:38:34,600 Speaker 1: inside of it, then you're only sensitive to the parts 812 00:38:34,600 --> 00:38:36,839 Speaker 1: of it that are closer to the center. Just like 813 00:38:36,880 --> 00:38:40,120 Speaker 1: if you drill the whole inside the Earth and jumped inside, 814 00:38:40,440 --> 00:38:43,000 Speaker 1: the force of gravity on you would decrease as you 815 00:38:43,000 --> 00:38:44,959 Speaker 1: are closer and closer because a lot of the stuff 816 00:38:44,960 --> 00:38:48,040 Speaker 1: would now be outside of your shell. You could ignore it, 817 00:38:48,200 --> 00:38:49,919 Speaker 1: and when you get to the very center, there would 818 00:38:49,920 --> 00:38:51,960 Speaker 1: be no force of gravity, so you can no longer 819 00:38:52,040 --> 00:38:54,240 Speaker 1: treat and the Earth is like just a point particle. 820 00:38:54,320 --> 00:38:55,840 Speaker 1: Was the mass of the Earth, and so it's the 821 00:38:55,880 --> 00:38:57,920 Speaker 1: same thing with the galaxy. In order to explain the 822 00:38:58,000 --> 00:39:00,720 Speaker 1: velocity of stars, we have to distribute be the mass 823 00:39:00,719 --> 00:39:03,000 Speaker 1: in just the right way to make these stars go 824 00:39:03,080 --> 00:39:05,120 Speaker 1: fast and these starts to go a little slower. So 825 00:39:05,160 --> 00:39:07,480 Speaker 1: the cool thing about this velocity measurement is that we're 826 00:39:07,480 --> 00:39:10,640 Speaker 1: not only sensitive to the overall amount of missing mass, 827 00:39:10,719 --> 00:39:14,319 Speaker 1: but also how it's distributed through the galaxy. Right. I 828 00:39:14,400 --> 00:39:17,400 Speaker 1: like that analogy about the Earth because like, if you 829 00:39:17,440 --> 00:39:19,160 Speaker 1: fall to the center of the Earth, and you're at 830 00:39:19,200 --> 00:39:21,560 Speaker 1: the center of the Earth, basically the Earth is all 831 00:39:21,600 --> 00:39:23,880 Speaker 1: around you and it's pulling you in every direction, so 832 00:39:23,920 --> 00:39:26,359 Speaker 1: you're basically weightless right in the middle of the Earth. Yeah, 833 00:39:26,360 --> 00:39:28,799 Speaker 1: there's no force of gravity at the center of the Earth. Yeah, 834 00:39:28,840 --> 00:39:31,160 Speaker 1: And so the same would be with a galaxy. Like 835 00:39:31,280 --> 00:39:34,120 Speaker 1: if you're at the center of the galaxy and you 836 00:39:34,160 --> 00:39:36,600 Speaker 1: would feel the dark matter pulling all around you, so 837 00:39:36,640 --> 00:39:39,439 Speaker 1: you wouldn't feel this mass, but if you were out 838 00:39:39,440 --> 00:39:42,280 Speaker 1: in the edge of the galaxy, you would feel the 839 00:39:42,320 --> 00:39:45,000 Speaker 1: mass of the dark matter like it was a point 840 00:39:45,040 --> 00:39:47,879 Speaker 1: in the middle. Yeah, exactly. So imagine now a star 841 00:39:48,000 --> 00:39:50,200 Speaker 1: that's very close to the center of the galaxy. If 842 00:39:50,239 --> 00:39:52,239 Speaker 1: you took all the dark matter and you put it 843 00:39:52,280 --> 00:39:54,839 Speaker 1: inside the black hole, that would mean that that star 844 00:39:54,960 --> 00:39:57,520 Speaker 1: is feeling all of that gravity, would be moving really 845 00:39:57,520 --> 00:40:00,239 Speaker 1: really fast. If instead you took that dark matter, you 846 00:40:00,280 --> 00:40:02,320 Speaker 1: spread it out through the galaxy, then most of it 847 00:40:02,360 --> 00:40:05,080 Speaker 1: wouldn't affect that star near the core, because, as you say, 848 00:40:05,200 --> 00:40:06,840 Speaker 1: it would all be balanced out, it will all be 849 00:40:06,840 --> 00:40:09,359 Speaker 1: on the outside of it. It would be null. And 850 00:40:09,480 --> 00:40:12,239 Speaker 1: so you can tell how it's distributed by looking at 851 00:40:12,239 --> 00:40:14,319 Speaker 1: the velocity stars that are close to the center and 852 00:40:14,320 --> 00:40:16,240 Speaker 1: then a little further away. In a little further away, 853 00:40:16,320 --> 00:40:18,680 Speaker 1: a distributed mass of dark matter makes a very different 854 00:40:18,680 --> 00:40:21,920 Speaker 1: prediction than dark matter concentrated all at the core of 855 00:40:21,960 --> 00:40:24,239 Speaker 1: the galaxy. All right, So then that's the answer of 856 00:40:24,280 --> 00:40:27,480 Speaker 1: the answer is that a black hole cannot explain the 857 00:40:27,480 --> 00:40:30,680 Speaker 1: missing mass in the galaxies and the trajectory of stars. 858 00:40:30,880 --> 00:40:34,160 Speaker 1: You kind of need something large and diffused like how 859 00:40:34,200 --> 00:40:37,279 Speaker 1: we think dark matter is. But there's also a possible 860 00:40:37,360 --> 00:40:40,440 Speaker 1: yes maybe to his answer, which is that we don't 861 00:40:40,560 --> 00:40:43,120 Speaker 1: think that all of the dark matter is in the 862 00:40:43,120 --> 00:40:45,640 Speaker 1: black hole the center of our galaxy. But remember that 863 00:40:45,680 --> 00:40:48,319 Speaker 1: we don't know what dark matter is, and there's a 864 00:40:48,320 --> 00:40:51,320 Speaker 1: possibility that dark matter, though it's spread out through the galaxy, 865 00:40:51,640 --> 00:40:54,759 Speaker 1: might be a bunch of smaller black holes, right like 866 00:40:54,840 --> 00:40:57,920 Speaker 1: primordial black holes. Right, Yes, black holes made in the 867 00:40:58,000 --> 00:41:00,759 Speaker 1: very first few moments before there was and stuff and 868 00:41:00,840 --> 00:41:03,880 Speaker 1: matter in the universe. They could still be around and 869 00:41:03,960 --> 00:41:06,200 Speaker 1: they could account for the dark matter. It's one of 870 00:41:06,200 --> 00:41:08,560 Speaker 1: the theories that are out there. It's maybe not the 871 00:41:08,600 --> 00:41:11,799 Speaker 1: most common or highly voted theory of dark matter, but 872 00:41:11,840 --> 00:41:14,479 Speaker 1: it's still possible. It's still plausible, and we haven't figured 873 00:41:14,520 --> 00:41:16,120 Speaker 1: out what dark matter is, so it could just be 874 00:41:16,200 --> 00:41:18,960 Speaker 1: a bunch of black holes spread out through the galaxy. Wow, 875 00:41:19,160 --> 00:41:21,839 Speaker 1: that sounds a little horrifying to know then, Like if 876 00:41:21,840 --> 00:41:24,800 Speaker 1: you were flying through space, it's like riddled with minds 877 00:41:24,880 --> 00:41:26,719 Speaker 1: kind of right. You might be flying through space and 878 00:41:26,920 --> 00:41:29,360 Speaker 1: there's a hole. You've flying through a cloud of little 879 00:41:29,440 --> 00:41:31,960 Speaker 1: tiny black holes. That wouldn't be good for your spaceship, right, 880 00:41:32,000 --> 00:41:33,640 Speaker 1: that would not be good for your spaceship. But you know, 881 00:41:33,800 --> 00:41:37,120 Speaker 1: it's eaten zero earths so far, so it must be 882 00:41:37,160 --> 00:41:41,520 Speaker 1: pretty safe so far. Zero. No, We've been flying through 883 00:41:41,520 --> 00:41:44,719 Speaker 1: the galaxy for billions of years, right, and we have 884 00:41:44,760 --> 00:41:47,000 Speaker 1: not yet run into a black hole. On the other hand, 885 00:41:47,280 --> 00:41:49,040 Speaker 1: we don't know if there are other planets out there 886 00:41:49,080 --> 00:41:51,520 Speaker 1: that have fallen into primordial black holes, because they've they 887 00:41:51,520 --> 00:41:53,520 Speaker 1: had we wouldn't see them, so it's not really a 888 00:41:53,560 --> 00:41:56,479 Speaker 1: great argument. All right. Well, then the answer is that 889 00:41:56,680 --> 00:41:58,560 Speaker 1: a black hole at the center of the galaxy wouldn't 890 00:41:58,560 --> 00:42:02,120 Speaker 1: explain dark matter. But maybe dark matter is explained by little, 891 00:42:02,160 --> 00:42:05,719 Speaker 1: tiny black holes everywhere. But it's great thinking one to 892 00:42:05,840 --> 00:42:08,399 Speaker 1: try to come up with some other explanation for dark 893 00:42:08,440 --> 00:42:10,400 Speaker 1: matter in terms of like the things we do know 894 00:42:10,560 --> 00:42:13,160 Speaker 1: and our uncertainties about them. It's a great way to 895 00:42:13,160 --> 00:42:17,000 Speaker 1: exercise your brain and do physics and think about different hypotheses. 896 00:42:17,040 --> 00:42:20,320 Speaker 1: So great idea. Cool. So those are three awesome questions 897 00:42:20,360 --> 00:42:23,040 Speaker 1: about black holes than you do think. We've on our 898 00:42:23,120 --> 00:42:26,040 Speaker 1: job here to fill the black hole of questions about 899 00:42:26,080 --> 00:42:28,520 Speaker 1: black holes a little bit. Yeah. The problem is that 900 00:42:28,560 --> 00:42:31,200 Speaker 1: the black hole questions just grow the more you feed them. 901 00:42:31,239 --> 00:42:33,799 Speaker 1: The bigger gets, the stronger it's pulled, the more we 902 00:42:33,840 --> 00:42:36,120 Speaker 1: want to know. It's just kind of like science that way. 903 00:42:36,160 --> 00:42:38,359 Speaker 1: The more we ask questions and get answers, the more 904 00:42:38,440 --> 00:42:41,240 Speaker 1: questions we have. Yeah, and hopefully we won't get stuck 905 00:42:41,239 --> 00:42:43,480 Speaker 1: in them forever. At some point we'll get out of 906 00:42:43,520 --> 00:42:45,439 Speaker 1: them or maybe Inside the black Hole is a really 907 00:42:45,480 --> 00:42:48,000 Speaker 1: wonderful book, filled with the secrets of the universe and 908 00:42:48,040 --> 00:42:51,200 Speaker 1: a cozy reading nook to enjoy it in Yeah, who 909 00:42:51,239 --> 00:42:54,120 Speaker 1: doesn't love a good book about the universe? Titled Frequently 910 00:42:54,160 --> 00:42:57,800 Speaker 1: Asked Questions about the un that's right Hypothetically at universe 911 00:42:57,880 --> 00:42:59,680 Speaker 1: f a q dot com. You'll have to run an 912 00:42:59,680 --> 00:43:02,680 Speaker 1: expair meant to see if it's a real website universe 913 00:43:02,760 --> 00:43:04,719 Speaker 1: f a q dot com. You might find a black hole, 914 00:43:04,800 --> 00:43:07,000 Speaker 1: or you might find a lot of interesting knowledge that's 915 00:43:07,080 --> 00:43:09,480 Speaker 1: right and funny cartoon, and so go check it out, 916 00:43:09,520 --> 00:43:11,400 Speaker 1: Go be a scientist. Those of you who write in 917 00:43:11,480 --> 00:43:14,200 Speaker 1: asking how can we support the podcast, this is how 918 00:43:14,239 --> 00:43:16,440 Speaker 1: you can support the podcast. Please go out there and 919 00:43:16,520 --> 00:43:18,440 Speaker 1: check out our book. We put a lot of energy 920 00:43:18,480 --> 00:43:19,960 Speaker 1: and a lot of fun and a lot of love 921 00:43:19,960 --> 00:43:22,359 Speaker 1: into it, and we hope that you all enjoy it. Yeah. 922 00:43:22,360 --> 00:43:24,719 Speaker 1: And more importantly, it's also those of you wondering, like 923 00:43:24,760 --> 00:43:27,640 Speaker 1: how can I tell my friends or my cousin or 924 00:43:27,680 --> 00:43:30,080 Speaker 1: my uncle or my mom, Like how cool all of 925 00:43:30,120 --> 00:43:32,080 Speaker 1: this stuff is this book? I think it's a great 926 00:43:32,120 --> 00:43:34,280 Speaker 1: way into these topics. You think it's going to convert 927 00:43:34,440 --> 00:43:37,600 Speaker 1: the physics skeptics out there are an all physicists skeptics. 928 00:43:37,920 --> 00:43:41,239 Speaker 1: I thought that was your thing, like that was your identifier. Yeah, 929 00:43:41,280 --> 00:43:45,600 Speaker 1: but some people are skeptics about physicists, skeptic about skepticism, 930 00:43:45,920 --> 00:43:48,520 Speaker 1: meta skeptics. All right, well, please go check it out 931 00:43:48,719 --> 00:43:51,520 Speaker 1: and please send us more of your questions. Was really 932 00:43:51,520 --> 00:43:53,800 Speaker 1: fun to get and really fun to answer on the podcast. 933 00:43:53,920 --> 00:43:56,680 Speaker 1: That's right. Please don't hesitate right to us any questions 934 00:43:56,719 --> 00:43:59,560 Speaker 1: you have about physics, except of course, homework problems to 935 00:44:00,040 --> 00:44:02,719 Speaker 1: Westerns at Daniel and Jorge dot com. I hope you 936 00:44:02,800 --> 00:44:05,520 Speaker 1: enjoyed that. Thanks for joining us, see you next time. 937 00:44:13,320 --> 00:44:16,200 Speaker 1: Thanks for listening, and remember that Daniel and Jorge explained. 938 00:44:16,200 --> 00:44:19,120 Speaker 1: The Universe is a production of I Heart Radio or 939 00:44:19,239 --> 00:44:22,160 Speaker 1: more podcast for my heart Radio, visit the I Heart 940 00:44:22,239 --> 00:44:25,839 Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your 941 00:44:25,880 --> 00:44:26,640 Speaker 1: favorite shows.