WEBVTT 1 00:00:00.320 --> 00:00:04.679 Hey, everyone, This is Katie Mack, your friendly neighborhood cosmologist 2 00:00:04.839 --> 00:00:09.279 and connoisseur of cosmic catastrophes. It's been a while since 3 00:00:09.359 --> 00:00:12.119 I've talked to on ologies, and a lot of things 4 00:00:12.160 --> 00:00:15.519 have been happening since that time. I have published a 5 00:00:15.519 --> 00:00:19.480 book called The End of Everything, Astrophysically Speaking, which is 6 00:00:19.679 --> 00:00:22.359 all about different ways the universe might end and what 7 00:00:22.440 --> 00:00:25.600 those would look like. And I've moved to a new place. 8 00:00:25.839 --> 00:00:28.600 When I recorded this, I was just about to start 9 00:00:28.600 --> 00:00:31.719 a job at North Carolina State University, where I was 10 00:00:31.879 --> 00:00:35.280 an assistant professor of physics, and about a year ago 11 00:00:35.399 --> 00:00:40.359 I moved to the Perimeter Institute for Theoretical Physics in Ontario, Canada, 12 00:00:40.960 --> 00:00:43.479 and there I have a really cool job title, which 13 00:00:43.600 --> 00:00:47.399 is the Hawking Chair in Cosmology and Science Communication. And 14 00:00:47.560 --> 00:00:50.679 at the Perimeter Institute, I continue my research on dark matter, 15 00:00:50.920 --> 00:00:54.280 and I work on a number of other early universe 16 00:00:54.399 --> 00:00:58.200 kinds of questions, and I do a bunch of public 17 00:00:58.200 --> 00:01:00.920 engagement outreach things like that, give a lot of talks, 18 00:01:01.039 --> 00:01:04.000 I do radio things, and I'm working on a new 19 00:01:04.040 --> 00:01:06.319 book which will come out in a couple of years 20 00:01:06.719 --> 00:01:12.040 that's about particle physics. So this episode is an episode 21 00:01:12.079 --> 00:01:15.920 from twenty seventeen. The end of twenty seventeen, and a 22 00:01:15.959 --> 00:01:18.439 lot has happened in physics since then. In terms of 23 00:01:18.439 --> 00:01:21.079 what I talked about on the episode, there's a bit 24 00:01:21.120 --> 00:01:24.239 of an update for the Ligo experiment. At the time, 25 00:01:24.319 --> 00:01:27.400 there were just a handful of detections of black holes 26 00:01:27.439 --> 00:01:30.439 colliding and other galaxies, which is just amazing. But now 27 00:01:30.480 --> 00:01:33.079 there have been something like ninety detections of black holes 28 00:01:33.120 --> 00:01:35.959 colliding in other galaxies. There'll be some discussion in the 29 00:01:36.000 --> 00:01:39.640 episode about gravitational waves that we see from those. Another 30 00:01:39.680 --> 00:01:42.920 thing that we talked about is super massive black holes 31 00:01:42.920 --> 00:01:44.840 and what they would look like if you could see them, 32 00:01:45.040 --> 00:01:48.280 and in the movie Interstellar there was a simulation of 33 00:01:48.280 --> 00:01:51.359 what that would look like. Since then, astronomers I've actually 34 00:01:51.640 --> 00:01:55.400 seen that they've actually seen the light from stuff falling 35 00:01:55.439 --> 00:01:58.640 into black holes and the black hole shadow that's produced 36 00:01:58.799 --> 00:02:02.040 when the light gets eaten by the black holes. So 37 00:02:02.439 --> 00:02:07.079 there's an experiment called the Event Horizon Telescope project where 38 00:02:07.480 --> 00:02:12.639 astronomers basically linked together telescopes all over the world and 39 00:02:13.000 --> 00:02:17.680 created an image of a couple of supermassive black holes. So, yeah, 40 00:02:17.840 --> 00:02:21.400 really exciting stuff. Check out those things, and I hope 41 00:02:21.400 --> 00:02:25.400 you enjoy this little blast from the past of cosmology. 42 00:02:26.080 --> 00:02:29.919 Hey, welcome to Ologies. I'm your Allie Warren, the host. 43 00:02:30.199 --> 00:02:32.599 Now each week I sit down with an ologist, I 44 00:02:32.680 --> 00:02:35.520 ask why do they love what they do? What is 45 00:02:35.560 --> 00:02:37.800 your deal? What should we know about it? And this 46 00:02:37.879 --> 00:02:43.599 week we cover the whole fucking universe which has existed 47 00:02:43.719 --> 00:02:46.840 and it's expanding and you're floating in it and you're 48 00:02:46.840 --> 00:02:49.599 made out of particles and matter and forces we don't 49 00:02:49.599 --> 00:02:54.120 even understand, and maybe there are multiverses and is this reality? 50 00:02:54.280 --> 00:02:56.439 And what are you doing here? And does anything matter? 51 00:02:56.599 --> 00:02:58.479 And of course it does. But should you be afraid 52 00:02:58.479 --> 00:03:01.560 of wearing bright lipstick or dancing in public? Probably not. No, 53 00:03:01.719 --> 00:03:03.919 in the scope of things, and the scope of things 54 00:03:05.479 --> 00:03:10.199 is really it's giant. It's called cosmology. Now, if you 55 00:03:10.240 --> 00:03:12.599 think that you listen to this episode already because you 56 00:03:12.719 --> 00:03:16.639 learn some stuff about beard care and face wash, think again, suckers. 57 00:03:17.159 --> 00:03:21.599 That was cosmetology. This week is cosmology, the study of 58 00:03:21.639 --> 00:03:25.400 the cosmos. And so when I say this episode is 59 00:03:25.439 --> 00:03:31.039 like everything, it's actually everything. It's the whole universe. It's 60 00:03:31.879 --> 00:03:35.080 it's a lot, it's a lot, it's so much it's 61 00:03:35.120 --> 00:03:38.319 a two parter. It's a two fur So this week 62 00:03:38.400 --> 00:03:41.560 we'll get the nuts and bolts of what astrophysics is, 63 00:03:42.520 --> 00:03:46.000 and after about an hour you will walk away cocktail 64 00:03:46.039 --> 00:03:50.120 party literate on goddamn astrophysics. Kind of I don't know. 65 00:03:50.360 --> 00:03:53.439 I'm learning here with you. Of all the episodes I've done, 66 00:03:53.520 --> 00:03:55.439 this was probably the one I knew the least about. 67 00:03:55.840 --> 00:04:00.000 So let's learn together, shall we? Part two of this now? 68 00:04:00.000 --> 00:04:03.919 Next week? Are your questions submitted via Patreon and the 69 00:04:03.960 --> 00:04:08.319 Ologies Podcast Facebook group. Y'all had good ones. Next week 70 00:04:08.360 --> 00:04:12.280 will address them now. The etymology of cosmology Cosmos with 71 00:04:12.319 --> 00:04:15.319 a K is the kicky little Greek word for world 72 00:04:15.840 --> 00:04:19.560 or order. So cosmology is a study of planets and such, sure, 73 00:04:20.279 --> 00:04:24.800 but also why and what and how? Where? What's huh? 74 00:04:24.879 --> 00:04:28.639 It's the study of what. This week's cosmologist is someone 75 00:04:29.079 --> 00:04:32.439 I've had a fawning Twitter fascination with for a while, 76 00:04:32.800 --> 00:04:35.360 and I met through a group of science friends I love, 77 00:04:35.519 --> 00:04:37.879 known to some as the nerd Brigade. Were kind of 78 00:04:37.920 --> 00:04:40.079 like a gang but with a website. But I was 79 00:04:40.160 --> 00:04:44.279 always kind of intimidated by her because she is, in 80 00:04:44.319 --> 00:04:48.720 her own words, an academic nomad and She continent hops 81 00:04:49.120 --> 00:04:53.040 while studying particle physics and black holes and gravitational waves, 82 00:04:53.040 --> 00:04:55.319 and she hangs out with Stephen Hawking. So when I 83 00:04:55.360 --> 00:04:57.759 met her through friends, I usually just sat at brunch 84 00:04:57.879 --> 00:05:00.199 like a barnacle and tried to look away when she 85 00:05:00.240 --> 00:05:02.439 caught me staring at her, so I asked her to 86 00:05:02.439 --> 00:05:05.240 be on the podcast. She said yes, and I immediately 87 00:05:05.279 --> 00:05:09.079 started perspiring. So she came to my apartment. We sat down, 88 00:05:09.240 --> 00:05:12.800 and my usual hour interview stretched to almost two, hence 89 00:05:12.839 --> 00:05:17.439 the two parter. Hours before she politely reminded me that 90 00:05:17.480 --> 00:05:19.439 we were supposed to be meeting people for a movie 91 00:05:19.480 --> 00:05:22.519 and we should stop. I'm so so glad we did 92 00:05:22.519 --> 00:05:25.160 this podcast because I got to know her even better 93 00:05:25.199 --> 00:05:27.839 as a friend, which, y'all, I'm going to be cheesy 94 00:05:28.079 --> 00:05:30.879 and say it's a true honor. So in this episode, 95 00:05:31.079 --> 00:05:34.600 you'll learn about the things that make you you, and 96 00:05:34.680 --> 00:05:38.360 the stars that exploded to make the things that make you, 97 00:05:38.800 --> 00:05:41.399 and the scale of our existence in space, and what 98 00:05:41.480 --> 00:05:43.920 it feels like to be heckled by Stephen Hawking and 99 00:05:44.000 --> 00:05:47.439 if this is real life, and if astrophysicists are just 100 00:05:47.800 --> 00:05:50.360 like making bullshit up that the rest of us just 101 00:05:50.439 --> 00:05:52.439 accept because we're like, man, I don't even know how 102 00:05:52.439 --> 00:05:55.399 to read these equations. So okay, So you'll get at 103 00:05:55.399 --> 00:05:58.600 the very least a loose grasp on just the whole 104 00:05:58.600 --> 00:06:01.879 of existence and maybe steel yourself to be the biggest 105 00:06:02.079 --> 00:06:05.360 you you want to be, and more importantly, get to 106 00:06:05.399 --> 00:06:09.720 know better one of the world's finest voices in cosmology. 107 00:06:09.959 --> 00:06:14.319 You know her as astro Kti on Twitter aka astrophysicist 108 00:06:14.879 --> 00:06:37.600 Katie mac. So take me back to defining some stuff 109 00:06:37.639 --> 00:06:40.759 because as a layman, as a lay woman over here, 110 00:06:41.920 --> 00:06:46.680 a lay human, Yes, I don't know the difference between 111 00:06:47.160 --> 00:06:52.480 a physicist, an astrophysicist, a particle physicist, an experimentalist, a cosmologist, 112 00:06:52.560 --> 00:06:56.240 and an astronomer. I don't know what those are, and 113 00:06:56.279 --> 00:06:59.000 I'm either going to have to Wikipedia this or I 114 00:06:59.000 --> 00:07:00.399 can have you give me a down. 115 00:07:01.079 --> 00:07:05.040 So these things are, they're a little bit like fluid, 116 00:07:05.079 --> 00:07:11.959 these definitions. So astronomer is basically somebody who studies space 117 00:07:12.079 --> 00:07:16.759 in some way. And usually when people say astronomer versus astrophysicists, 118 00:07:16.839 --> 00:07:20.839 usually astronomer is like more on the observational side or 119 00:07:21.120 --> 00:07:25.079 sort of describing stuff in space. Astrophysicists is more about 120 00:07:25.120 --> 00:07:27.959 like trying to understand how the physics of the thing 121 00:07:28.040 --> 00:07:30.480 in space works. So you can be an astrophysicist trying 122 00:07:30.480 --> 00:07:33.879 to understand how galaxies form, for example, and so you're 123 00:07:33.920 --> 00:07:39.319 applying physics to this stuff in space. If you're a 124 00:07:39.319 --> 00:07:44.720 particle physicist, you're working on like how particle interactions work, 125 00:07:45.279 --> 00:07:48.959 so like you know anomsmasters and things. Large Tadron Collider 126 00:07:49.079 --> 00:07:55.279 exposon usually. I mean the like classic particle experiment is 127 00:07:55.279 --> 00:07:57.040 you take two particles and you smash them together and 128 00:07:57.079 --> 00:07:59.920 you see what comes out. That's what the Large tadronical 129 00:08:00.360 --> 00:08:00.680 is doing. 130 00:08:00.800 --> 00:08:03.839 Now. The LHC, that's what you call the Large Hadron 131 00:08:03.879 --> 00:08:06.879 Collider when y'all are tight. So you've maybe heard of it, 132 00:08:07.040 --> 00:08:08.839 you kind of know, like it's a thing in Europe, 133 00:08:08.879 --> 00:08:11.480 maybe has something to do with atoms. I looked into it. 134 00:08:11.720 --> 00:08:15.920 The Large Hadron Collider is located near the France Switzerland border, 135 00:08:15.920 --> 00:08:19.680 and it's a circular tunnel. It's over five hundred feet 136 00:08:19.759 --> 00:08:23.639 deep in some parts, and it's seventeen miles around. It 137 00:08:23.720 --> 00:08:27.920 is the largest machine in the world. So this thing 138 00:08:28.279 --> 00:08:31.839 consists of over twelve hundred magnets and they're cooled to 139 00:08:31.920 --> 00:08:36.000 a temperature colder than outer space, and then the magnets 140 00:08:36.399 --> 00:08:40.720 accelerate protons to almost the speed of light, and then 141 00:08:40.720 --> 00:08:45.720 the protons are bashed together. It's very punk rock, very expensive. 142 00:08:46.120 --> 00:08:49.720 The LHC was mostly completed in two thousand and eight. 143 00:08:49.840 --> 00:08:52.919 Over ten thousand scientists and engineers worked on it. Now 144 00:08:52.960 --> 00:08:55.679 in photos it looks kind of like a giant, well 145 00:08:55.759 --> 00:09:00.960 lit subway tunnel, but with less p and rap. If 146 00:09:01.000 --> 00:09:03.759 you're like, I can't remember what a proton is because 147 00:09:03.799 --> 00:09:07.440 I'm not required to anymore I'm not in school, don't worry. 148 00:09:08.000 --> 00:09:10.559 Neither did I. I had to google, like how does 149 00:09:10.559 --> 00:09:12.919 an atom work? I forgot, so I'll brush you up. 150 00:09:13.120 --> 00:09:18.360 So matter is stuff, and molecules are some atoms stuck together. 151 00:09:18.840 --> 00:09:21.279 Atoms are made of a nucleus, which is a little 152 00:09:21.279 --> 00:09:26.519 cluster of neutrons and protons. Protons have a positive charge, 153 00:09:26.559 --> 00:09:32.559 pro electrons have an equal negative charge, and electrons are 154 00:09:32.720 --> 00:09:38.240 bebopping zooming around whirling derbish style outside of the nucleus. 155 00:09:38.519 --> 00:09:40.879 So the neutrons and protons, which are the ones that 156 00:09:40.919 --> 00:09:44.440 are just cuddling in the nucleus, those are made of 157 00:09:44.559 --> 00:09:48.840 smaller particles called quarks, and the quarks come in a 158 00:09:48.919 --> 00:09:54.279 couple different varieties. So what gives these particles their mass? 159 00:09:54.639 --> 00:09:57.279 What are they? Where do they come from? We've got 160 00:09:57.279 --> 00:09:59.879 all these little tiny things that make up matter. Okay, 161 00:10:00.080 --> 00:10:03.679 so I heard it explained that there's a field called 162 00:10:03.720 --> 00:10:06.919 the Higgs field. It's named after one alive and well 163 00:10:07.039 --> 00:10:11.679 Scotsman physicist named Peter Higgs. And how a particle interacts 164 00:10:11.720 --> 00:10:14.240 with the Higgs field gives it its mass, kind of 165 00:10:14.320 --> 00:10:19.519 like drag in water. So Higgs bosons are particles. They're 166 00:10:19.639 --> 00:10:21.879 an excitation of the Higgs field. It's kind of like 167 00:10:21.879 --> 00:10:24.480 a drop of water splashing from an ocean. So the 168 00:10:24.600 --> 00:10:28.559 Large Hadron Collider smashed protons together to see if they 169 00:10:28.600 --> 00:10:31.519 could prove that the Higgs boson exists. And guess what, 170 00:10:32.240 --> 00:10:35.559 bitches it does. You're not bitches. Some people call this 171 00:10:35.600 --> 00:10:39.159 the God particle because it's so fundamental to all matter 172 00:10:39.200 --> 00:10:42.360 in the universe. Does doctor Higgs like this name? No, 173 00:10:42.559 --> 00:10:44.799 he's an atheist. He thinks it sucks. And the guy 174 00:10:44.840 --> 00:10:47.799 who coined it the god particle actually wanted to call 175 00:10:47.840 --> 00:10:50.240 it the goddamn particle, but his publisher made him change 176 00:10:50.279 --> 00:10:54.519 it in a book. So the Large Hadron Collider one 177 00:10:54.519 --> 00:10:57.879 of the things it does smashes these protons together into 178 00:10:57.960 --> 00:11:02.039 smaller things to figure out why matter has mass. There 179 00:11:02.039 --> 00:11:05.960 you go. Also, the large hadron collider accidentally has its 180 00:11:06.039 --> 00:11:09.480 name spelled wrong on its own website as large hard 181 00:11:09.519 --> 00:11:15.080 on collider Once would be mortifying. But what if they 182 00:11:15.080 --> 00:11:18.519 did it more than once, like twice or five times? 183 00:11:18.879 --> 00:11:21.840 That's impossible, is it? Because a search on their site 184 00:11:21.879 --> 00:11:26.759 revealed they'd spelled it large hard on collider one hundred 185 00:11:27.159 --> 00:11:32.639 and sixty five times. Thank god particle for that. That's 186 00:11:32.960 --> 00:11:36.480 just precious. So whenever you're like, I don't understand this stuff, 187 00:11:36.519 --> 00:11:39.720 maybe I'm not smart enough, just think someone typed in 188 00:11:40.200 --> 00:11:44.919 large hard on collider over one hundred and fifty times 189 00:11:45.399 --> 00:11:47.759 and they built the thing. So how else do people 190 00:11:47.799 --> 00:11:50.240 figure this shit out? About very important things that we 191 00:11:50.279 --> 00:11:50.759 can't see? 192 00:11:50.799 --> 00:11:53.679 But there are other ways to do particle physics measuring 193 00:11:53.720 --> 00:11:57.799 how particles interact with each other, throwing particles that other things, 194 00:11:58.320 --> 00:12:00.799 accelerating stuff, and seeing what happens. All of that kind 195 00:12:00.840 --> 00:12:03.480 of stuff. On the experimental side and on the theory side, 196 00:12:03.519 --> 00:12:06.919 it's a lot about trying to understand like the fundamental 197 00:12:06.960 --> 00:12:11.879 forces of nature, so like how how atoms hold together, 198 00:12:12.679 --> 00:12:16.720 how you know, particles can change into other particles in 199 00:12:16.759 --> 00:12:21.159 certain conditions. How gravity fits into all that, which it 200 00:12:21.240 --> 00:12:25.399 doesn't at the moment theoretically, Okay, okay, it's very hard 201 00:12:25.480 --> 00:12:28.080 to get gravity and particle physics to work together. This 202 00:12:28.200 --> 00:12:31.120 is kind of yeah, it's it's sort of. This may 203 00:12:31.120 --> 00:12:34.120 be another topic, but like, this is the reason string 204 00:12:34.159 --> 00:12:35.039 theory was invented. 205 00:12:35.120 --> 00:12:38.000 Real quick, what is string theory? Well, in a very 206 00:12:38.120 --> 00:12:42.240 quark sized, tiny nutshell, the premise of string theory is 207 00:12:42.279 --> 00:12:46.519 that basic objects are not point like, but they're string like. 208 00:12:46.919 --> 00:12:49.799 So a quark might be made of a loop that 209 00:12:49.960 --> 00:12:54.279 kind of vibrates and moves around. Every kind of particle 210 00:12:54.360 --> 00:12:58.039 is like a different wiggly string. So why does anyone care? 211 00:12:58.120 --> 00:13:00.759 Why are people so horny for string theory? Well, number one, 212 00:13:00.799 --> 00:13:02.799 it's from the eighties, and maybe this is like the 213 00:13:02.840 --> 00:13:06.519 scrunchy of particle physics. I don't know. More importantly, string 214 00:13:06.600 --> 00:13:09.600 theory is a theory that works with both Einstein's general 215 00:13:09.639 --> 00:13:15.440 relativity and that mister Einstein pose that what we perceive 216 00:13:15.639 --> 00:13:19.679 as the force of gravity is the curvature of space 217 00:13:19.759 --> 00:13:23.600 and time. More on that in a minute, and quantum mechanics, 218 00:13:23.840 --> 00:13:27.120 which is the physics of the tiniest building blocks that exist. 219 00:13:27.480 --> 00:13:30.799 So remember those quirks that made up protons and neutrons, 220 00:13:31.000 --> 00:13:33.960 what are those made of? Maybe these string like loops 221 00:13:33.960 --> 00:13:38.200 of matter. Every time I hear string theory mentioned, I 222 00:13:38.200 --> 00:13:41.200 think of string cheese. I cannot And I was writing 223 00:13:41.240 --> 00:13:44.559 and researching this episode, and I found myself on a 224 00:13:44.600 --> 00:13:49.440 website like two thirty in the morning learning that string cheese, 225 00:13:49.919 --> 00:13:52.360 as we know what, was invented in Wisconsin in nineteen 226 00:13:52.399 --> 00:13:55.559 seventy six. And the way they get it to string 227 00:13:55.720 --> 00:13:57.840 is to heat it to one hundred and forty degrees fahrenheit, 228 00:13:58.360 --> 00:14:02.320 and that aligns all the proteins. Also, the first iterations 229 00:14:02.320 --> 00:14:05.360 of string cheese were bigger and chunkier and served to 230 00:14:05.480 --> 00:14:09.000 drunks in bars. Should we get back to physics, Okay, I'm. 231 00:14:08.840 --> 00:14:12.240 Sorry, And this is like the big question in physics 232 00:14:12.320 --> 00:14:16.399 is that, like, so, there there are a few sort 233 00:14:16.399 --> 00:14:21.639 of fundamental forces of nature. Right, there's electromagnetism, there's that, 234 00:14:21.799 --> 00:14:26.879 and that's like light and you know, like static cling 235 00:14:26.919 --> 00:14:29.200 and and all of those kinds of things, right, and 236 00:14:29.200 --> 00:14:32.879 and magnetism, and then there's the weak nuclear force, which 237 00:14:32.960 --> 00:14:36.919 has to do with like how particles decay in radioactivity 238 00:14:36.919 --> 00:14:39.159 that kind of thing, and how particles can change into 239 00:14:39.159 --> 00:14:42.679 other particles under certain conditions. There's the strong nuclear force 240 00:14:42.759 --> 00:14:46.240 and that holds particles together in the centers of atoms. Okay, 241 00:14:47.120 --> 00:14:50.519 and those all kind of make sense together theoretically, like 242 00:14:50.559 --> 00:14:54.039 you can write down equations that make those all fit 243 00:14:54.080 --> 00:14:56.919 in some way more or less. 244 00:14:56.960 --> 00:15:00.600 When Katie says you can write down equation that make 245 00:15:00.600 --> 00:15:03.960 those all fit, I appreciate her being inclusive with the 246 00:15:04.000 --> 00:15:08.120 second person, but I cannot write down equations to make 247 00:15:08.159 --> 00:15:11.519 those all fit in some way. I cannot do that. 248 00:15:11.559 --> 00:15:14.759 But then there's gravity, and gravity just doesn't follow any 249 00:15:14.799 --> 00:15:19.320 of the same rules. It's like it's very hard to put 250 00:15:19.360 --> 00:15:22.960 together a theory that includes those the fundamental forces of 251 00:15:23.000 --> 00:15:25.360 particle physics and gravity. 252 00:15:25.840 --> 00:15:28.120 So so it's gravity like the bad boy in a 253 00:15:28.159 --> 00:15:31.159 teen drama. It's just like it's just not following any rules. 254 00:15:31.240 --> 00:15:34.879 It's weird. It's like like gravity is all about space time, 255 00:15:35.200 --> 00:15:38.159 you know, so gravity like, so the theory of gravity 256 00:15:38.159 --> 00:15:42.759 that we have is Einstein's theory of relativity, so general relativity. 257 00:15:42.799 --> 00:15:44.480 This is the theory of gravity where. 258 00:15:44.399 --> 00:15:49.240 Okay, yeah, ready, heres Einstein. Here's how the universe of 259 00:15:49.279 --> 00:15:51.120 which you are a part works. 260 00:15:51.480 --> 00:15:54.879 The basic picture is that you can think of space 261 00:15:55.120 --> 00:15:58.240 as this malleable thing, and if you have something that 262 00:15:58.279 --> 00:16:00.879 has mass, it creates like a dentist space sort of 263 00:16:00.919 --> 00:16:05.840 bends space around it, okay, and so other things moving 264 00:16:05.879 --> 00:16:08.519 past will respond to that and like fall into that dent. 265 00:16:09.039 --> 00:16:12.000 And that's like how gravitational attraction works. You can think 266 00:16:12.039 --> 00:16:14.320 of it in this geometric way, okay, and it works 267 00:16:14.360 --> 00:16:16.840 really well like geometrically to think of it like that. 268 00:16:17.120 --> 00:16:20.240 But then there are fundamental principles that happen in that, 269 00:16:20.360 --> 00:16:23.480 like the speed of light as a limiting factor and 270 00:16:24.360 --> 00:16:26.480 all sorts of things like that, so only certain paths 271 00:16:26.519 --> 00:16:30.320 things can follow and everything. But then the particle physics stuff, 272 00:16:30.360 --> 00:16:33.200 like all the equations of particle physics are done without 273 00:16:33.399 --> 00:16:37.159 thinking about gravity because on those scales, like gravity isn't important. 274 00:16:37.159 --> 00:16:41.720 It's a really really weak force, okay. But also like 275 00:16:41.759 --> 00:16:46.320 there are the way that the particle physics is formulated 276 00:16:46.360 --> 00:16:48.519 in the standard Model of particle physics, which is what 277 00:16:49.399 --> 00:16:52.960 we use to talk about all these interactions, it doesn't 278 00:16:52.960 --> 00:16:56.600 have the same like it doesn't follow the same rules 279 00:16:56.960 --> 00:16:59.679 as gravity, Like there are ways in which the whole 280 00:17:00.080 --> 00:17:03.679 like speed of light thing is violated in one way 281 00:17:03.720 --> 00:17:08.079 that you can formulate how particles move around, which is 282 00:17:08.160 --> 00:17:09.960 kind of like there's kind of like there's this way 283 00:17:09.960 --> 00:17:12.400 of formulating it where a particle going from point A 284 00:17:12.440 --> 00:17:15.640 to point B passes through every possible path on the 285 00:17:15.680 --> 00:17:17.920 way between point A and point B, and it's only 286 00:17:18.000 --> 00:17:22.400 by by using that idea that you get the right 287 00:17:22.440 --> 00:17:25.680 answer for how that particle is moving in the particle 288 00:17:25.720 --> 00:17:28.640 physics point of view. And that doesn't work with relativity. 289 00:17:29.440 --> 00:17:31.119 So there are a couple of things like that where 290 00:17:31.200 --> 00:17:35.440 like quantum mechanics and relativity just do not like each 291 00:17:35.480 --> 00:17:40.319 other really, And it gets especially problematic when you get 292 00:17:40.359 --> 00:17:43.599 to black hole because a black hole is this very 293 00:17:44.279 --> 00:17:48.640 like intense gravitational system HM. It's basically a dent in 294 00:17:48.720 --> 00:17:51.200 space time that's so deep that like everything falls into 295 00:17:51.200 --> 00:17:55.839 it if it gets close enough. But at the edge 296 00:17:55.880 --> 00:17:57.920 of a black hole, the event horizon, you have this 297 00:17:57.960 --> 00:18:00.759 weird quantum mechanical thing happening where you can have like 298 00:18:00.839 --> 00:18:05.680 particles evaporating off of it, and that sets like a 299 00:18:05.799 --> 00:18:09.880 sort of scale of the black hole, and that means 300 00:18:09.880 --> 00:18:13.960 there's quantum mechanics happening in a strong gravitational system and 301 00:18:14.000 --> 00:18:18.079 then just everything breaks. It just goes totally haywire, because 302 00:18:19.079 --> 00:18:21.559 if you look at it from a gravitational point of view, 303 00:18:21.559 --> 00:18:24.000 like a relativity point of view, you should see nothing 304 00:18:24.039 --> 00:18:26.640 at all interesting happening when you when you fall into 305 00:18:26.680 --> 00:18:29.400 the black hole, like aside from like you're you're killed 306 00:18:29.440 --> 00:18:33.359 by the gravity, but like you don't see like nothing 307 00:18:33.400 --> 00:18:36.079 weird happens when you pass the horizon. But from a 308 00:18:36.440 --> 00:18:39.960 particle physics point of view, like there there might be 309 00:18:40.079 --> 00:18:42.440 like this like firewall, like there might be like a 310 00:18:42.480 --> 00:18:46.799 sort of like boundary of intense radiation there. Because of 311 00:18:46.839 --> 00:18:48.799 the way you have to think about how the particle 312 00:18:48.880 --> 00:18:54.519 physics works. This is a complicated story, but. 313 00:18:53.319 --> 00:18:58.880 Basically the astrophysics typically is yeah, I'm not explaining it 314 00:18:58.960 --> 00:19:03.039 very well, but but basically. 315 00:19:02.640 --> 00:19:06.039 Like like basically, when you get to that point when 316 00:19:06.079 --> 00:19:08.960 you have a black hole that has an evaporation happening 317 00:19:08.960 --> 00:19:11.640 where particles are coming off the edge of the event horizon, 318 00:19:13.359 --> 00:19:15.720 one way of looking at it says that that that 319 00:19:15.799 --> 00:19:18.880 means that whatever you fought through into the black hole, 320 00:19:18.920 --> 00:19:21.400 you can't ever find out what it was. That information 321 00:19:21.480 --> 00:19:25.319 is destroid. But quantum mechanics like the particle point of 322 00:19:25.400 --> 00:19:27.559 view says you can't do that, and so there has 323 00:19:27.599 --> 00:19:30.599 to be some kind of loophole and then gravity doesn't 324 00:19:30.720 --> 00:19:32.960 like that and you just you just end up with chaos. 325 00:19:32.960 --> 00:19:36.200 And so there's this there's this big problem called the 326 00:19:36.200 --> 00:19:40.440 black hole information paradox, which has been around forever, and 327 00:19:40.519 --> 00:19:42.519 every once in a while somebody's like, oh, I solved it, 328 00:19:42.599 --> 00:19:45.480 and then it's really complicated and people don't really understand 329 00:19:45.519 --> 00:19:46.160 how that works. 330 00:19:46.279 --> 00:19:47.680 Has anyone actually solved that? 331 00:19:48.279 --> 00:19:52.720 I mean, I so technically I'm just not qualified to 332 00:19:52.839 --> 00:19:56.240 know that for sure, because it requires understanding quantum gravity 333 00:19:56.240 --> 00:19:59.319 in a way that I do not. But there have 334 00:19:59.359 --> 00:20:03.240 been some solution suggested, but in general there's still a 335 00:20:03.279 --> 00:20:06.359 lot of discussion. So I don't know. 336 00:20:06.519 --> 00:20:10.160 Okay, wait, so what does a cosmologist do. 337 00:20:10.680 --> 00:20:15.640 Cosmologist just means you study the universe as a whole, right, 338 00:20:15.759 --> 00:20:18.400 so you study maybe the beginning of the universe, the 339 00:20:18.480 --> 00:20:22.559 end of the universe, how it changes over time. But 340 00:20:22.920 --> 00:20:26.240 you can be a physicist cosmologist or an astronomer cosmologist, 341 00:20:26.319 --> 00:20:31.240 and those are different and and it's culturally different, like 342 00:20:31.279 --> 00:20:35.160 but the so if you if you're a physicist, if 343 00:20:35.440 --> 00:20:37.519 you hang out with particle physics people and you say 344 00:20:37.519 --> 00:20:40.480 you're a cosmologists, then then the implication is that you 345 00:20:40.559 --> 00:20:43.519 work on like the beginning of the universe and the 346 00:20:43.559 --> 00:20:47.720 forces of nature and maybe the end of the universe 347 00:20:48.119 --> 00:20:50.480 something like that. If you hang out with astrophysicists and 348 00:20:50.480 --> 00:20:53.240 you say you're a cosmologist, then you just study things 349 00:20:53.240 --> 00:20:56.559 that are really far away, or you study, you know, 350 00:20:57.880 --> 00:21:00.440 some something you know more fundamental. But you can be 351 00:21:00.480 --> 00:21:03.440 a cosmologist in astrophysics and you're a cosmologist because you 352 00:21:03.519 --> 00:21:07.119 study very very distant galaxies. The reason that counts as 353 00:21:07.119 --> 00:21:10.119 cosmology is because that means you're studying the very distant 354 00:21:10.200 --> 00:21:11.400 past of the universe. 355 00:21:11.599 --> 00:21:15.359 So there are different flavors of cosmology, but they're all 356 00:21:15.480 --> 00:21:18.000 kind of linked, at least in my opinion, by like, 357 00:21:18.079 --> 00:21:20.319 oh where are we? What are we? What are we 358 00:21:20.400 --> 00:21:24.680 made of? AKA, it's a branch of astronomy that involves 359 00:21:24.680 --> 00:21:28.480 the origin and evolution of the universe. That's a less 360 00:21:28.519 --> 00:21:29.559 panicky way to put it. 361 00:21:30.559 --> 00:21:34.680 And so then you're studying like how the universe has 362 00:21:34.759 --> 00:21:37.200 changed over time. So there are kind of different ways 363 00:21:37.200 --> 00:21:40.440 of doing it. And I've done all of those different 364 00:21:40.480 --> 00:21:43.880 kinds of cosmology. I guess because I've spent my time 365 00:21:43.960 --> 00:21:46.279 kind of bouncing back and forth between the particle physics 366 00:21:46.319 --> 00:21:50.079 and the astrophysics communities. So I've worked on you know, 367 00:21:50.440 --> 00:21:53.400 the Big Bang and like theories of the early universe, 368 00:21:53.480 --> 00:21:57.319 and I've worked on distant galaxies and how galaxies form. 369 00:21:57.359 --> 00:22:00.279 And I've worked on black holes and weird stuf like 370 00:22:00.359 --> 00:22:04.720 cosmic strings and just all sorts of things. 371 00:22:04.759 --> 00:22:05.799 What is a cosmic string? 372 00:22:06.079 --> 00:22:09.480 A cosmic string is kind of like a sort of 373 00:22:09.720 --> 00:22:13.319 line or wiggly line of energy that stretches across the cosmos. 374 00:22:13.599 --> 00:22:16.480 Might not exist, probably doesn't exist, but there could be 375 00:22:17.000 --> 00:22:21.480 this like whole network of strings of Like it's kind 376 00:22:21.480 --> 00:22:23.079 of like if you think of like a black hole, 377 00:22:23.119 --> 00:22:26.240 but you like stretch it out across the whole universe. 378 00:22:26.839 --> 00:22:30.119 You get It's kind of like that, what does it do? What? 379 00:22:30.319 --> 00:22:30.359 It? 380 00:22:30.720 --> 00:22:33.279 So really interesting things. So if you have two cosmic 381 00:22:33.319 --> 00:22:37.039 strings and they cross each other they collide, they can 382 00:22:37.119 --> 00:22:39.480 like reconnect in a different way. So you can have 383 00:22:39.519 --> 00:22:41.759 two cosmic strings that are about to collide and then 384 00:22:41.799 --> 00:22:44.759 they they like change so that now you have two 385 00:22:44.759 --> 00:22:48.079 sort of loops of cosmic strings. They're going intopposite directions, like, 386 00:22:48.160 --> 00:22:50.319 so they sort of pass through each other by branching 387 00:22:50.400 --> 00:22:51.400 off in this weird way. 388 00:22:51.519 --> 00:22:54.880 So cosmic strings may or may not exist. Now, if 389 00:22:54.920 --> 00:23:00.000 they do exist, some theorists have used them to maybe 390 00:23:00.119 --> 00:23:03.839 catch out some stuff about time travel. Please figure that out, 391 00:23:04.119 --> 00:23:05.559 please fix some stuff. Thank you. 392 00:23:05.839 --> 00:23:08.039 And you can make a loop of cosmic string, and 393 00:23:08.039 --> 00:23:11.160 then that loop of cosmic string will like wiggle around 394 00:23:11.200 --> 00:23:18.759 and make gravitational radiation and disappear into nothingness. And if 395 00:23:18.759 --> 00:23:22.039 you have a cosmic string, like if you have a 396 00:23:22.079 --> 00:23:25.519 cosmic string between you and some distant galaxy, then you 397 00:23:25.559 --> 00:23:28.079 might see two pictures of that galaxy because it like 398 00:23:28.279 --> 00:23:31.240 splits the space kind of. It's really cool. 399 00:23:31.680 --> 00:23:34.000 Now, how much do you think about all of this 400 00:23:34.079 --> 00:23:35.920 in your day to day life? And like when you're 401 00:23:35.960 --> 00:23:38.799