1 00:00:00,160 --> 00:00:05,520 Speaker 1: My welcome to Stuff to Blow Your Mind from how 2 00:00:05,559 --> 00:00:14,000 Speaker 1: Stuff Works dot com. Hey you welcome to Stuff to 3 00:00:14,000 --> 00:00:16,120 Speaker 1: Blow your Mind. My name is Robert Lamb and I'm 4 00:00:16,200 --> 00:00:19,240 Speaker 1: Joe McCormick, and we're back. It's part two of our 5 00:00:19,320 --> 00:00:22,360 Speaker 1: multi part exploration of black holes. Because you know what, 6 00:00:22,440 --> 00:00:25,239 Speaker 1: this year Robert went to the World Science Festival in 7 00:00:25,239 --> 00:00:27,520 Speaker 1: New York and came back with black Hole Fever. Yeah. 8 00:00:27,560 --> 00:00:28,880 Speaker 1: It was a great It was a great talk that 9 00:00:28,920 --> 00:00:30,680 Speaker 1: really opened my eyes a little more to some of 10 00:00:30,760 --> 00:00:33,720 Speaker 1: the finer details of of black holes. And you mean 11 00:00:33,760 --> 00:00:36,800 Speaker 1: that Brian Green talk with the guests. Yeah, Darkness made visible, 12 00:00:37,159 --> 00:00:40,040 Speaker 1: wonderful talk. It's available online. Will include a link to 13 00:00:40,040 --> 00:00:42,760 Speaker 1: that in the landing page for this episode. Certainly inspired 14 00:00:42,840 --> 00:00:45,760 Speaker 1: us to to really give black holes a proper shake 15 00:00:45,840 --> 00:00:47,640 Speaker 1: on Stuff to Blow your Mind. Yeah, I mean, there's 16 00:00:47,680 --> 00:00:49,840 Speaker 1: so much interesting stuff to talk about, and the fact 17 00:00:49,840 --> 00:00:52,120 Speaker 1: that they're just one of the most interesting objects in 18 00:00:52,159 --> 00:00:55,520 Speaker 1: the entire universe. It's not that they're probably I would say, 19 00:00:55,560 --> 00:00:59,080 Speaker 1: maybe the most interesting non living thing in the universe. 20 00:00:59,360 --> 00:01:01,640 Speaker 1: What do you think about that? Yeah, yeah, I would 21 00:01:01,680 --> 00:01:05,200 Speaker 1: say that because we're pretty interesting ultimately humans are. Um. 22 00:01:05,240 --> 00:01:07,200 Speaker 1: I do want to remind everyone. If you did not 23 00:01:07,360 --> 00:01:09,880 Speaker 1: listen to the previous episode on black holes, you do 24 00:01:09,959 --> 00:01:11,760 Speaker 1: want to go back and listen to it, because this 25 00:01:11,840 --> 00:01:13,200 Speaker 1: is this is not one of those where you can 26 00:01:13,240 --> 00:01:15,119 Speaker 1: kind of take part one and part two in any order. 27 00:01:15,319 --> 00:01:17,240 Speaker 1: You really need to hit the first episode. I mean, 28 00:01:17,280 --> 00:01:19,080 Speaker 1: you could if you really wanted, But we're going to 29 00:01:19,160 --> 00:01:21,440 Speaker 1: be referring back to the groundwork we laid in the 30 00:01:21,440 --> 00:01:23,840 Speaker 1: previous episode. And the previous episode we talked a lot 31 00:01:23,880 --> 00:01:27,200 Speaker 1: about the development of black holes. Uh, sort of as 32 00:01:27,240 --> 00:01:30,520 Speaker 1: the history of an idea, something that was unlike the 33 00:01:30,600 --> 00:01:32,920 Speaker 1: stars in the sky. You know, the stars in the sky, 34 00:01:33,040 --> 00:01:36,119 Speaker 1: we first observed and we could see them, and then 35 00:01:36,480 --> 00:01:39,080 Speaker 1: by making observations about them, we were able to come 36 00:01:39,160 --> 00:01:42,319 Speaker 1: up with theories to explain them. Black holes weren't like that. 37 00:01:42,360 --> 00:01:45,120 Speaker 1: It went the other way around. Black Holes existed in 38 00:01:45,280 --> 00:01:49,080 Speaker 1: theory long before anybody accepted that they existed in reality, 39 00:01:49,120 --> 00:01:53,560 Speaker 1: and long after they existed in theory, many scientists ardently 40 00:01:53,600 --> 00:01:57,000 Speaker 1: opposed the idea that black holes could exist in nature. Yeah, 41 00:01:57,000 --> 00:02:00,560 Speaker 1: it's the idea that that these various individuals said, well, X, Y, 42 00:02:00,600 --> 00:02:05,520 Speaker 1: and Z are true, then this thing might exist and uh, 43 00:02:05,640 --> 00:02:08,960 Speaker 1: and and that thing is the black hole. But of course, 44 00:02:09,080 --> 00:02:12,320 Speaker 1: you know, lots of people when a thing sounds outlandish, 45 00:02:12,520 --> 00:02:15,560 Speaker 1: even if your best theories tell you it might be possible, 46 00:02:15,919 --> 00:02:17,760 Speaker 1: people want to find a way to say, no, that 47 00:02:17,880 --> 00:02:20,800 Speaker 1: just sounds unintuitive. It couldn't be real. It doesn't fit 48 00:02:20,919 --> 00:02:24,560 Speaker 1: my picture of how the universe works. It doesn't feel right. Yeah, 49 00:02:25,000 --> 00:02:28,079 Speaker 1: maybe that's a thought experiment, but I doubt will actually 50 00:02:28,120 --> 00:02:31,320 Speaker 1: find something like this when we start looking out into 51 00:02:31,320 --> 00:02:34,800 Speaker 1: the cosmos with better observational technology. You know, it's often 52 00:02:34,840 --> 00:02:38,120 Speaker 1: said that Albert Einstein did some of his worst work ever, 53 00:02:38,240 --> 00:02:41,200 Speaker 1: Like the worst science of his entire career was him 54 00:02:41,240 --> 00:02:44,480 Speaker 1: trying to write papers to prove that black holes didn't 55 00:02:44,520 --> 00:02:48,080 Speaker 1: exist in reality. It just didn't seem right to him, 56 00:02:48,120 --> 00:02:51,280 Speaker 1: even though his general relativity became the basis of our 57 00:02:51,320 --> 00:02:54,920 Speaker 1: modern theory of black holes. But so anyway, yeah, so 58 00:02:54,960 --> 00:02:59,120 Speaker 1: how did today? We want to explore making the darkness flesh, 59 00:02:59,320 --> 00:03:02,400 Speaker 1: making the black hole into a thing that is real 60 00:03:02,760 --> 00:03:05,480 Speaker 1: in existence in the universe and we can detect it. 61 00:03:05,800 --> 00:03:07,600 Speaker 1: So I think first we want to tell the story 62 00:03:07,639 --> 00:03:09,760 Speaker 1: of sort of like a bridging the gap between the 63 00:03:10,120 --> 00:03:14,840 Speaker 1: black holes of general relativity theory and the actual observations 64 00:03:14,880 --> 00:03:16,720 Speaker 1: of them and then talk a little bit about what's 65 00:03:16,760 --> 00:03:18,960 Speaker 1: it like to detect black holes and how we might 66 00:03:19,000 --> 00:03:21,880 Speaker 1: do it. And we do have to distress that in 67 00:03:21,960 --> 00:03:25,880 Speaker 1: today's world, black holes are pretty much an established reality. 68 00:03:26,040 --> 00:03:28,679 Speaker 1: You talk to experts and they say yes, without a 69 00:03:28,680 --> 00:03:30,839 Speaker 1: shadow of a doubt. Yeah. I don't know if it's 70 00:03:30,880 --> 00:03:33,639 Speaker 1: the case that every single expert would say without a 71 00:03:33,639 --> 00:03:36,240 Speaker 1: shadow of a doubt, but yeah, they're They're generally accepted 72 00:03:36,280 --> 00:03:38,680 Speaker 1: as a fact of reality. You know, we've reached the 73 00:03:38,680 --> 00:03:42,720 Speaker 1: point where black holes exist and they're completely non politicized. 74 00:03:43,120 --> 00:03:46,240 Speaker 1: That's the other great Yeah, oh man, I love a 75 00:03:46,240 --> 00:03:49,880 Speaker 1: scientific controversy that doesn't never have a political angle. Yeah, 76 00:03:50,000 --> 00:03:53,280 Speaker 1: it's the black holes are are. Thus far, they've remained 77 00:03:53,280 --> 00:03:55,400 Speaker 1: pretty safe. Well, maybe we can muck it up today. 78 00:03:55,840 --> 00:03:59,320 Speaker 1: Let's let's get people taking tribal sides on it. Okay, 79 00:03:59,320 --> 00:04:02,160 Speaker 1: So the story of how black holes went from this 80 00:04:02,320 --> 00:04:05,840 Speaker 1: theoretical anomaly to a thing known to exist in the world, 81 00:04:06,280 --> 00:04:09,760 Speaker 1: it's a long, complicated story, so we definitely can't explore 82 00:04:09,800 --> 00:04:11,040 Speaker 1: all of it, but I just want to mention a 83 00:04:11,040 --> 00:04:14,800 Speaker 1: few highlights, and one of the first ones is serious 84 00:04:14,840 --> 00:04:18,880 Speaker 1: b Now, Serious is the brightest star in the night. 85 00:04:18,920 --> 00:04:22,000 Speaker 1: Sky from Earth, often known as the Dog Star because 86 00:04:22,040 --> 00:04:26,120 Speaker 1: it's part of the Cannus Major constellation, the Great Dog constellation. 87 00:04:26,520 --> 00:04:28,839 Speaker 1: Side note, I didn't know this until I was reading 88 00:04:28,839 --> 00:04:31,000 Speaker 1: this the other day. Do you know the origin of 89 00:04:31,040 --> 00:04:35,240 Speaker 1: the term dog days of summer doesn't actually have anything 90 00:04:35,279 --> 00:04:37,599 Speaker 1: to do with the behavior of dogs. Really. I always 91 00:04:37,600 --> 00:04:40,360 Speaker 1: thought it came from a Don Henley song. Wait, one 92 00:04:40,360 --> 00:04:43,360 Speaker 1: of the Boys of Summer. Sorry, after the dog Days 93 00:04:43,400 --> 00:04:46,680 Speaker 1: of Summer have gone. Yeah, man, I grew so hard 94 00:04:46,720 --> 00:04:48,800 Speaker 1: whenever that song comes on the radios. It's a great 95 00:04:49,000 --> 00:04:50,720 Speaker 1: it's a great track. I love it. It's yacht rock 96 00:04:50,880 --> 00:04:54,120 Speaker 1: that touches my heart. Yeah. So the term dog days 97 00:04:54,120 --> 00:04:58,160 Speaker 1: of Summer actually refers to the period of Serious, the 98 00:04:58,839 --> 00:05:03,120 Speaker 1: star in the Cannus Major constellation, rising roughly in conjunction 99 00:05:03,200 --> 00:05:06,039 Speaker 1: with the Sun, which happens in July through August in 100 00:05:06,040 --> 00:05:08,800 Speaker 1: the Northern Hemisphere, and so this is also the hottest 101 00:05:08,800 --> 00:05:10,960 Speaker 1: time of the summer, and so it came to be 102 00:05:11,000 --> 00:05:14,120 Speaker 1: associated with Okay, so Serious is coming up with the 103 00:05:14,160 --> 00:05:16,640 Speaker 1: sun in the morning, and that means it's going to 104 00:05:16,680 --> 00:05:19,640 Speaker 1: be real hot out. But back in the eighteen hundreds, 105 00:05:20,680 --> 00:05:23,600 Speaker 1: it had been observed that the extremely bright star we 106 00:05:23,680 --> 00:05:29,280 Speaker 1: now call Serious A behaved oddly. Its motion was not 107 00:05:29,480 --> 00:05:32,120 Speaker 1: it was it was not smooth. It was kind of wobbly, 108 00:05:32,680 --> 00:05:36,160 Speaker 1: as if it were being destabilized and tugged on by 109 00:05:36,160 --> 00:05:40,359 Speaker 1: an invisible hand. And it turned out that Serious A 110 00:05:40,360 --> 00:05:44,159 Speaker 1: actually had a very dim companion star. It was a 111 00:05:44,160 --> 00:05:47,560 Speaker 1: binary star system, and the companion was what we now 112 00:05:47,600 --> 00:05:50,640 Speaker 1: call Serious B. But it was a very strange type 113 00:05:50,680 --> 00:05:53,799 Speaker 1: of companion because based on the motion of the two 114 00:05:53,839 --> 00:05:58,640 Speaker 1: bodies and the light they produced, astrophysicists could calculate that 115 00:05:58,839 --> 00:06:02,600 Speaker 1: the companion of Sirius at the same time was somewhere 116 00:06:02,600 --> 00:06:05,320 Speaker 1: around the mass of our Sun, and yet was barely 117 00:06:05,400 --> 00:06:10,240 Speaker 1: larger than the size of planet Earth and burning extremely hot, 118 00:06:10,400 --> 00:06:14,160 Speaker 1: much hotter than the Sun. So Serious Be turned out 119 00:06:14,240 --> 00:06:16,320 Speaker 1: to be an early example of what would later be 120 00:06:16,360 --> 00:06:20,720 Speaker 1: called a white dwarf, a tiny, hot, massive star that 121 00:06:20,800 --> 00:06:25,719 Speaker 1: proved matter could be compressed to pressures previously thought absolutely impossible. 122 00:06:26,320 --> 00:06:29,440 Speaker 1: In the words of Arthur Eddington, quote a ton, and 123 00:06:29,480 --> 00:06:32,200 Speaker 1: he's talking about the the material making up the star. 124 00:06:32,320 --> 00:06:35,200 Speaker 1: A ton of this material would be a little nugget 125 00:06:35,240 --> 00:06:38,200 Speaker 1: that you could put in a matchbox. So imagine something 126 00:06:38,240 --> 00:06:41,600 Speaker 1: matchbox size. But that weighs a ton, and so for many, 127 00:06:41,680 --> 00:06:45,800 Speaker 1: including Eddington, the very concept of this density was so 128 00:06:45,880 --> 00:06:48,640 Speaker 1: absurd that it should just basically cause us to dismiss 129 00:06:48,680 --> 00:06:51,279 Speaker 1: the observations out of hand, dismiss the idea of a 130 00:06:51,279 --> 00:06:56,120 Speaker 1: white dwarf. It's absurd, but reality is stranger than our imagination. 131 00:06:56,200 --> 00:06:58,640 Speaker 1: White dwarves came to be accepted as a feature of 132 00:06:58,640 --> 00:07:02,000 Speaker 1: the universe and a part of ller revolution, especially after 133 00:07:02,120 --> 00:07:06,279 Speaker 1: quantum mechanics eventually came along. To explain how matter could 134 00:07:06,320 --> 00:07:10,200 Speaker 1: be compressed to such an unbelievable density. Basically has to 135 00:07:10,240 --> 00:07:13,440 Speaker 1: do with packing atomic nuclei tighter and tighter, and you 136 00:07:13,480 --> 00:07:15,760 Speaker 1: can actually do this to some extent because most of 137 00:07:15,760 --> 00:07:18,480 Speaker 1: an adam is empty space. There's a good explanation of 138 00:07:18,480 --> 00:07:20,640 Speaker 1: this actually in a book that's one of our sources 139 00:07:20,680 --> 00:07:24,120 Speaker 1: on this episode, Black Hole, by Marcia Bartousciak, which I 140 00:07:24,160 --> 00:07:27,720 Speaker 1: thought I should mention again, which is a good good 141 00:07:27,720 --> 00:07:29,320 Speaker 1: book if you want to go in more depth than 142 00:07:29,320 --> 00:07:32,040 Speaker 1: we're going into here. But so with serious b you've 143 00:07:32,080 --> 00:07:35,200 Speaker 1: got these white dwarves, You've got these objects that are 144 00:07:35,280 --> 00:07:39,400 Speaker 1: observed to be tiny and very hot and very bright 145 00:07:39,560 --> 00:07:43,000 Speaker 1: and very massive, and so what would be the limits 146 00:07:43,040 --> 00:07:46,200 Speaker 1: on what a star like that could be like uh 147 00:07:46,280 --> 00:07:50,720 Speaker 1: In nineteen thirty, the young Indian astrophysicist Supermania and Chandra 148 00:07:50,800 --> 00:07:54,880 Speaker 1: Sheker calculated that there was an upper limit to the 149 00:07:54,920 --> 00:07:58,280 Speaker 1: mass of a white dwarf. White dwarves could vary in size, 150 00:07:58,320 --> 00:08:02,880 Speaker 1: but somewhere around one point four solar masses. If a 151 00:08:02,880 --> 00:08:06,000 Speaker 1: white dwarf is about one point four times the mass 152 00:08:06,080 --> 00:08:09,640 Speaker 1: of our Sun, something happens. This is now known as 153 00:08:09,720 --> 00:08:12,720 Speaker 1: the chander Shaker limit, and it around this mass, the 154 00:08:12,800 --> 00:08:17,440 Speaker 1: force of gravity chander Shaker calculated appears to become more 155 00:08:17,480 --> 00:08:22,680 Speaker 1: powerful than the force that's known as the electron degeneracy pressure. 156 00:08:22,960 --> 00:08:25,160 Speaker 1: And what that is is it just causes atoms to 157 00:08:25,240 --> 00:08:28,560 Speaker 1: push against one another and resist compression. So why can't 158 00:08:28,640 --> 00:08:31,360 Speaker 1: you keep compressing it down more and more? There's this 159 00:08:31,440 --> 00:08:36,880 Speaker 1: electron degeneracy pressure pushing back, but at a certain point, gravity, 160 00:08:36,920 --> 00:08:40,800 Speaker 1: at least on paper, appears to completely overwhelm this degeneracy 161 00:08:40,840 --> 00:08:45,000 Speaker 1: pressure and just crush everything down. So any clump of 162 00:08:45,040 --> 00:08:49,040 Speaker 1: white dwarf stellar matter more massive than this could not 163 00:08:49,360 --> 00:08:53,120 Speaker 1: maintain the white dwarf density at a stable pressure given 164 00:08:53,160 --> 00:08:55,800 Speaker 1: the laws of general relativity. Past this point of star's 165 00:08:55,800 --> 00:08:59,679 Speaker 1: density would just not scale up regularly, but would collapse, 166 00:09:00,000 --> 00:09:04,319 Speaker 1: and it would collapse toward infinity. But when you think 167 00:09:04,320 --> 00:09:07,400 Speaker 1: about that, like try to imagine your in Chonder Shaker's 168 00:09:07,640 --> 00:09:10,880 Speaker 1: position infinite density, what does it mean to collapse to 169 00:09:11,040 --> 00:09:14,280 Speaker 1: infinite density? You'd almost be tempted to think, Okay, well 170 00:09:14,320 --> 00:09:17,480 Speaker 1: I made a mistake. Yeah. It's like it's like suddenly 171 00:09:17,520 --> 00:09:19,640 Speaker 1: everything is reduced to zero and you know that the 172 00:09:19,679 --> 00:09:21,840 Speaker 1: equation must be flowed. Yeah, it's like you've you've hit 173 00:09:21,920 --> 00:09:24,760 Speaker 1: a divide by zero area or something. You you know 174 00:09:24,960 --> 00:09:28,199 Speaker 1: that you must have done something wrong. It was difficult 175 00:09:28,240 --> 00:09:31,120 Speaker 1: to believe that something like this could be possible in reality. 176 00:09:31,120 --> 00:09:34,480 Speaker 1: How could a real physical object collapse toward a point 177 00:09:34,480 --> 00:09:37,959 Speaker 1: of infinite density? Though this is what the math appeared 178 00:09:37,960 --> 00:09:41,600 Speaker 1: to show. But Chonder Shaker did not actually argue about 179 00:09:41,640 --> 00:09:44,959 Speaker 1: what physically happened to the white dwarf past the limit 180 00:09:45,040 --> 00:09:48,160 Speaker 1: that he had established, only that the limit of stability 181 00:09:48,240 --> 00:09:51,920 Speaker 1: at about one point four solar masses existed, and Chandra 182 00:09:52,000 --> 00:09:55,000 Speaker 1: Shaker spent years arguing against the grain of scholarship on 183 00:09:55,080 --> 00:09:57,520 Speaker 1: this point. There's a famous story about how when he 184 00:09:57,559 --> 00:09:59,960 Speaker 1: presented his findings at a meeting of the Royal last 185 00:10:00,000 --> 00:10:03,280 Speaker 1: Atronomical Society of London and nineteen thirty five our old 186 00:10:03,280 --> 00:10:07,000 Speaker 1: friend Arthur Eddington's uh. He supposedly exclaimed there should be 187 00:10:07,040 --> 00:10:09,480 Speaker 1: a law of nature to prevent a star from behaving 188 00:10:09,480 --> 00:10:15,080 Speaker 1: in this absurd way. That's some wicked cantankerousness, just like 189 00:10:15,240 --> 00:10:20,840 Speaker 1: yelling at the laws of physics. But but no, I 190 00:10:20,840 --> 00:10:23,920 Speaker 1: mean so, that kind of attitude from Eddington actually kept 191 00:10:24,000 --> 00:10:26,520 Speaker 1: this idea down for a long time, even though we 192 00:10:26,520 --> 00:10:28,640 Speaker 1: would eventually find out that chander Shaker was on the 193 00:10:28,720 --> 00:10:32,000 Speaker 1: right side of this argument, and the prolific Soviet physicist 194 00:10:32,120 --> 00:10:34,960 Speaker 1: live Landau also made a similar calculation around this point, 195 00:10:35,040 --> 00:10:37,800 Speaker 1: and he also arrived at the conclusion that a heavy 196 00:10:37,920 --> 00:10:40,680 Speaker 1: enough star could collapse to what appears to be a point. 197 00:10:41,080 --> 00:10:43,440 Speaker 1: But he said, that can't be quite right, so he 198 00:10:43,480 --> 00:10:46,840 Speaker 1: ignored this result and instead concluded that the core of 199 00:10:46,880 --> 00:10:49,280 Speaker 1: a star like this that at the core of a 200 00:10:49,280 --> 00:10:51,920 Speaker 1: star like this, matter sort of begins to ignore the 201 00:10:51,960 --> 00:10:55,839 Speaker 1: laws of physics and becomes quote, one gigantic nucleus. Now, 202 00:10:55,920 --> 00:10:58,839 Speaker 1: chander Shaker was eventually recognized for being in the right 203 00:10:58,880 --> 00:11:01,720 Speaker 1: on this question. He see the Nobel Prize in Physics 204 00:11:01,720 --> 00:11:04,360 Speaker 1: for his work on stellar evolution, and he got that 205 00:11:04,400 --> 00:11:07,720 Speaker 1: in nineteen eighty three. Now, also in the nineteen thirties, 206 00:11:07,720 --> 00:11:10,960 Speaker 1: a parallel idea to the idea of the black hole emerges, 207 00:11:11,120 --> 00:11:14,839 Speaker 1: and that is the idea of a neutron star. Now, 208 00:11:14,840 --> 00:11:19,079 Speaker 1: a neutron star is another form that stellar collapse can take, 209 00:11:19,120 --> 00:11:22,440 Speaker 1: in which you've got protons and electrons that form the 210 00:11:22,440 --> 00:11:24,920 Speaker 1: core of a star and they compressed together with such 211 00:11:25,000 --> 00:11:28,520 Speaker 1: force that they combine and form neutrons, which have mass 212 00:11:28,920 --> 00:11:32,280 Speaker 1: but no electric charge. And a neutron star is not 213 00:11:32,440 --> 00:11:35,280 Speaker 1: as a reality warping as a black hole, but it 214 00:11:35,400 --> 00:11:39,480 Speaker 1: is an unbelievably exotic type of object composed matter so 215 00:11:39,559 --> 00:11:42,760 Speaker 1: dense that it's been compared to an atomic nucleus the 216 00:11:42,800 --> 00:11:46,080 Speaker 1: size of a city. If you can picture that, Uh, 217 00:11:46,400 --> 00:11:49,040 Speaker 1: can you picture that? Of course you can't, nobody can, 218 00:11:49,400 --> 00:11:53,120 Speaker 1: but just just try. I can picture an illustration that 219 00:11:53,200 --> 00:11:57,040 Speaker 1: was presented of this. That's that's the best I can do. Well. 220 00:11:57,080 --> 00:11:59,319 Speaker 1: I mean, part of the problem is that matter already 221 00:11:59,360 --> 00:12:01,760 Speaker 1: looks solid enough to us, right, I mean, you take 222 00:12:01,800 --> 00:12:04,199 Speaker 1: a rock or something like that, You're like, this looks 223 00:12:04,280 --> 00:12:07,240 Speaker 1: really really solid, but most of it is empty space. 224 00:12:07,960 --> 00:12:10,600 Speaker 1: Most of it is just the space between the atomic 225 00:12:10,679 --> 00:12:14,240 Speaker 1: nuclei and the electrons orbiting them, and the other atomic 226 00:12:14,320 --> 00:12:18,160 Speaker 1: nuclei that they're bonded with. Um. I mean, the molecules 227 00:12:18,320 --> 00:12:22,120 Speaker 1: that make that very solid seeming object are mostly empty space, 228 00:12:22,400 --> 00:12:24,920 Speaker 1: and there's a lot of space you can press things 229 00:12:25,040 --> 00:12:28,719 Speaker 1: further and further into if you really must. You may 230 00:12:28,720 --> 00:12:30,360 Speaker 1: not be able to get blood from a stone, but 231 00:12:30,440 --> 00:12:32,920 Speaker 1: there's a lot of empty space there. If empty space 232 00:12:32,960 --> 00:12:34,920 Speaker 1: is when you're after, it's there, you can get space 233 00:12:34,960 --> 00:12:38,120 Speaker 1: from a stone. So, just to show how much things 234 00:12:38,160 --> 00:12:40,480 Speaker 1: can be compressed, it's often said that, like a square 235 00:12:40,600 --> 00:12:44,120 Speaker 1: centimeter of a neutron star, material might weigh more than 236 00:12:44,160 --> 00:12:48,680 Speaker 1: a billion tons. Uh So. In the late nineteen thirties, J. 237 00:12:48,840 --> 00:12:52,959 Speaker 1: Robert Oppenheimer, who's famous for working on the Manhattan Project, 238 00:12:53,000 --> 00:12:56,760 Speaker 1: among many things. Oppenheimer and some students of his published 239 00:12:56,800 --> 00:13:00,160 Speaker 1: work tending in the same direction as Chandra shako Are. 240 00:13:00,160 --> 00:13:03,520 Speaker 1: Oppenheimer and George Volkoff did work on the emerging idea 241 00:13:03,520 --> 00:13:05,960 Speaker 1: of neutron stars, which we were just talking about, and 242 00:13:05,960 --> 00:13:09,319 Speaker 1: found that neutron stars, like white dwarves, had an upper 243 00:13:09,440 --> 00:13:13,040 Speaker 1: limit of mass, after which something very strange seems to 244 00:13:13,120 --> 00:13:15,679 Speaker 1: happen to them. You've got this upper limit, and if 245 00:13:15,720 --> 00:13:18,920 Speaker 1: they have more mass than this limit, there's some kind 246 00:13:18,920 --> 00:13:23,599 Speaker 1: of collapse, something, something goes wrong with the physics. Oppenheimer 247 00:13:23,640 --> 00:13:26,960 Speaker 1: also published a paper on stellar evolution with Heartland Snyder 248 00:13:27,320 --> 00:13:30,640 Speaker 1: in which they determined that late stage stellar remnants of 249 00:13:30,679 --> 00:13:33,920 Speaker 1: stars passed a certain mass would seem to enter this 250 00:13:34,000 --> 00:13:37,960 Speaker 1: state of permanent infinite collapse. The matter within them would 251 00:13:37,960 --> 00:13:40,880 Speaker 1: exist in this perpetual free fall towards a point of 252 00:13:40,960 --> 00:13:44,520 Speaker 1: infinite density, the singularity. And that is a that is 253 00:13:44,559 --> 00:13:48,840 Speaker 1: a mind boggling concept to toy around with, falling forever. 254 00:13:49,880 --> 00:13:53,240 Speaker 1: The never ending pit essentially, which was it was something 255 00:13:53,240 --> 00:13:54,960 Speaker 1: like as a kid, you, or at least when I 256 00:13:55,000 --> 00:13:56,800 Speaker 1: was a kid, that's what we played instead of the 257 00:13:56,800 --> 00:13:58,520 Speaker 1: floor is lava. Always said the floor is an never 258 00:13:58,640 --> 00:14:01,439 Speaker 1: ending pit. That's more than lava. Yeah. I think it's 259 00:14:01,440 --> 00:14:04,400 Speaker 1: because we saw it on like key Man cartoons or something. 260 00:14:04,440 --> 00:14:07,319 Speaker 1: I feel like it isn't that what's underneath Castle Gray 261 00:14:07,320 --> 00:14:09,839 Speaker 1: Skull and never ending pit? I don't remember it is 262 00:14:09,880 --> 00:14:12,440 Speaker 1: in my mind. Well, then what's Castle gray Skull built on. 263 00:14:13,280 --> 00:14:15,360 Speaker 1: It's built over and never ending. I see it's called 264 00:14:15,360 --> 00:14:17,360 Speaker 1: a strut since yeah, yeah, I guess they had to 265 00:14:17,400 --> 00:14:20,120 Speaker 1: cap that thing, you know up, They're like, don't people 266 00:14:20,160 --> 00:14:21,920 Speaker 1: gonna fall into that, Let's put a castle on top 267 00:14:21,960 --> 00:14:25,000 Speaker 1: of it. So it's playing fast and loose with masters 268 00:14:25,000 --> 00:14:27,720 Speaker 1: of the universe. Um myth those here. By the way, 269 00:14:27,760 --> 00:14:29,960 Speaker 1: I apologize for just trying to move us along. I 270 00:14:29,960 --> 00:14:34,479 Speaker 1: think we should dwell. No, no, I'm good, I'm good. Okay, 271 00:14:34,720 --> 00:14:38,480 Speaker 1: don't ever let me be too square. Okay. Uh So, 272 00:14:38,680 --> 00:14:42,240 Speaker 1: starting in the nineteen fifties and sixties, both experimental and 273 00:14:42,320 --> 00:14:45,400 Speaker 1: theoretical work really seems to accelerate in the direction of 274 00:14:45,440 --> 00:14:48,920 Speaker 1: indicating the reality of neutron stars and black holes. These 275 00:14:49,040 --> 00:14:54,480 Speaker 1: these really exotic collapsed star remnant objects and theoretical models 276 00:14:55,040 --> 00:14:58,720 Speaker 1: are affirmed over and over and they appear increasingly sound. 277 00:14:58,800 --> 00:15:04,480 Speaker 1: While new astro comical observations really seem to make us think, wow, yeah, 278 00:15:04,480 --> 00:15:06,760 Speaker 1: there could be black holes out there. I think some 279 00:15:06,840 --> 00:15:09,920 Speaker 1: of the skepticism could be unfounded. Like in the nineteen 280 00:15:10,000 --> 00:15:14,360 Speaker 1: sixties you had scientists identifying quasars, which are these distant 281 00:15:14,400 --> 00:15:17,960 Speaker 1: high energy objects, possibly young galaxies, with black holes at 282 00:15:17,960 --> 00:15:21,120 Speaker 1: the center of them, emitting trillions of times the energy 283 00:15:21,120 --> 00:15:24,080 Speaker 1: of a sun. And you had pulsars, which are spinning 284 00:15:24,120 --> 00:15:27,640 Speaker 1: objects emitting a repeating pattern of radio bursts. And around 285 00:15:27,640 --> 00:15:31,120 Speaker 1: the same time, astronomers identified sources of X rays and 286 00:15:31,160 --> 00:15:34,360 Speaker 1: gamma rays from all over the celestial map. And these 287 00:15:34,400 --> 00:15:38,160 Speaker 1: signals really strongly pointed to the physical reality of collapse 288 00:15:38,200 --> 00:15:41,920 Speaker 1: stars like neutron stars and black holes. And now we 289 00:15:42,000 --> 00:15:45,280 Speaker 1: know that actually pretty much every mature galaxy in the 290 00:15:45,360 --> 00:15:48,640 Speaker 1: universe that we know of seems to have a supermassive 291 00:15:48,680 --> 00:15:51,200 Speaker 1: black hole at its center. It may be the black 292 00:15:51,200 --> 00:15:55,000 Speaker 1: holes are necessary for the formation of galaxies, and galaxies 293 00:15:55,080 --> 00:15:57,440 Speaker 1: are where things like us live. The black hole the 294 00:15:57,520 --> 00:16:03,080 Speaker 1: life giver. Yeah, we were rebrand rebranding the black hole today. So, 295 00:16:03,120 --> 00:16:06,240 Speaker 1: speaking of supermassive black holes, I I do want to 296 00:16:06,280 --> 00:16:09,920 Speaker 1: just touch in once more on the three forms of 297 00:16:09,960 --> 00:16:12,720 Speaker 1: black holes that we tend to discuss. Okay, so we've 298 00:16:12,760 --> 00:16:16,000 Speaker 1: mainly been talking about stellar black holes, right right. The 299 00:16:16,000 --> 00:16:17,960 Speaker 1: idea of a collapse star. Yeah, these would be as 300 00:16:18,040 --> 00:16:21,760 Speaker 1: massive as as twenty of our sons uh fit inside 301 00:16:21,760 --> 00:16:24,680 Speaker 1: a one mile radius sphere. Uh. These are the would 302 00:16:24,680 --> 00:16:27,080 Speaker 1: be the remnants of very massive stars that have run 303 00:16:27,120 --> 00:16:29,760 Speaker 1: through their innergy energy reserves. They go supernova and then 304 00:16:29,760 --> 00:16:32,360 Speaker 1: they collapse upon themselves and they're thought to be the 305 00:16:32,360 --> 00:16:35,920 Speaker 1: most common type of black holes, and there are likely 306 00:16:36,080 --> 00:16:39,320 Speaker 1: dozens within our own Milky Way galaxy. And then they're 307 00:16:39,320 --> 00:16:42,000 Speaker 1: the primordial black holes. These tho I touched on the 308 00:16:42,040 --> 00:16:44,560 Speaker 1: first episode that the size of an atom. They have 309 00:16:44,560 --> 00:16:47,080 Speaker 1: the massive a mountain, So these are hypothetical, and they 310 00:16:47,080 --> 00:16:50,520 Speaker 1: probably formed soon after the Big Bang. And then of 311 00:16:50,560 --> 00:16:54,600 Speaker 1: course they're the big ones, the supermassive black holes. They 312 00:16:54,640 --> 00:16:57,160 Speaker 1: likely exist at the center of most galaxies. Our own 313 00:16:57,400 --> 00:17:01,240 Speaker 1: galaxy boast Sagittarius A, and it has a mass equal 314 00:17:01,280 --> 00:17:05,639 Speaker 1: to about four million sons. And uh, these black holes 315 00:17:05,680 --> 00:17:09,760 Speaker 1: formed with their respective galaxies and are proportional in size. 316 00:17:10,119 --> 00:17:13,679 Speaker 1: And again these these are these are a part of 317 00:17:13,720 --> 00:17:16,560 Speaker 1: our universe. You know, as much as we we tend 318 00:17:16,560 --> 00:17:17,960 Speaker 1: to sort of fall into the trap of thinking of 319 00:17:18,000 --> 00:17:22,720 Speaker 1: black holes as you know, cosmic love crafty and evil consumers, 320 00:17:23,200 --> 00:17:26,520 Speaker 1: they're they're just a part of the life cycle of stars. 321 00:17:26,560 --> 00:17:30,280 Speaker 1: They are part of the general physical reality of the universe. Yeah, 322 00:17:30,320 --> 00:17:34,520 Speaker 1: they're not reapers from another dimension. They're the life givers. 323 00:17:36,520 --> 00:17:40,040 Speaker 1: Let's not go too far alright. Well, on that note, 324 00:17:40,480 --> 00:17:42,480 Speaker 1: we're gonna take a quick break and when we come back, 325 00:17:42,600 --> 00:17:47,399 Speaker 1: we will get into the science detecting black holes. Thank you, 326 00:17:47,600 --> 00:17:50,760 Speaker 1: thank you. All Right, we're back. So I want to 327 00:17:50,760 --> 00:17:54,840 Speaker 1: tell you a story about signas X one. Okay, let's 328 00:17:54,840 --> 00:17:56,840 Speaker 1: have it. So. Way back in the nineteen sixties and 329 00:17:56,880 --> 00:18:00,920 Speaker 1: the Swinging sixties, the astronomers out there, we're making use 330 00:18:00,960 --> 00:18:04,120 Speaker 1: of a new class of tools to study distant regions 331 00:18:04,119 --> 00:18:08,040 Speaker 1: of the sky, and these were space based X ray detectors. 332 00:18:08,480 --> 00:18:12,720 Speaker 1: They were attached to orbital rockets and artificial satellites, and 333 00:18:12,840 --> 00:18:16,159 Speaker 1: these instruments looked for X ray signals the astronomers and 334 00:18:16,200 --> 00:18:20,840 Speaker 1: astrophysicists thought they might find emanating from all kinds of 335 00:18:20,840 --> 00:18:24,000 Speaker 1: celestial sources, from say, the surface of the Moon. You know, 336 00:18:24,040 --> 00:18:27,560 Speaker 1: it's the moon shooting X rays. Two distant star systems 337 00:18:27,560 --> 00:18:31,960 Speaker 1: and nebulae, and one strong source of X ray radiation 338 00:18:32,040 --> 00:18:35,480 Speaker 1: detected by rockets in the nineteen sixties was a point 339 00:18:35,520 --> 00:18:39,040 Speaker 1: in the constellation Scorpius, and the source of the radiation 340 00:18:39,119 --> 00:18:41,560 Speaker 1: came to be known as s c O X one 341 00:18:41,680 --> 00:18:43,400 Speaker 1: or SCO X one. I don't know if you say 342 00:18:43,440 --> 00:18:45,720 Speaker 1: it like SCO that makes it sound kind of scummy, 343 00:18:46,640 --> 00:18:50,120 Speaker 1: but it was a truly remarkable fine because this radiation 344 00:18:50,200 --> 00:18:53,560 Speaker 1: source was about nine thousand light years from our solar system, 345 00:18:53,640 --> 00:18:57,280 Speaker 1: and it's X ray output was millions of times stronger 346 00:18:57,320 --> 00:19:01,000 Speaker 1: than that of normal sun like stars. And this massive 347 00:19:01,080 --> 00:19:04,960 Speaker 1: energy output came we discovered from a neutron star in 348 00:19:05,000 --> 00:19:08,919 Speaker 1: a binary system, and since then other similar sources have 349 00:19:09,040 --> 00:19:12,760 Speaker 1: been discovered. These X rays are generated when matter from 350 00:19:12,960 --> 00:19:14,600 Speaker 1: so you've got a binary system, you've got like a 351 00:19:14,640 --> 00:19:17,200 Speaker 1: neutron star or a black hole, and then some other 352 00:19:17,280 --> 00:19:21,160 Speaker 1: kind of object like a star. They're dancing, Yeah, they're 353 00:19:21,200 --> 00:19:24,720 Speaker 1: they're they're doing the polka out there in space. And 354 00:19:25,119 --> 00:19:28,280 Speaker 1: the X rays are generated when matter from the surface 355 00:19:28,320 --> 00:19:32,159 Speaker 1: of the more normal star gets sucked violently into the 356 00:19:32,200 --> 00:19:35,800 Speaker 1: gravitational field and onto the surface of the neutron star. 357 00:19:35,960 --> 00:19:38,159 Speaker 1: That's what's going on in the case of s c 358 00:19:38,320 --> 00:19:42,200 Speaker 1: O X one. And during so so this this gets 359 00:19:42,240 --> 00:19:44,560 Speaker 1: sucked in, the matter gets heated up a lot, and 360 00:19:44,840 --> 00:19:47,840 Speaker 1: X rays get blasted out into space. But during these 361 00:19:47,840 --> 00:19:50,439 Speaker 1: surveys of the nineteen sixties, one X ray source in 362 00:19:50,440 --> 00:19:53,840 Speaker 1: the sky was not like the others. In nineteen sixty 363 00:19:53,920 --> 00:19:55,840 Speaker 1: four we started to get a clear picture of the 364 00:19:55,960 --> 00:20:00,119 Speaker 1: radiation output of one source in the Sickness constellation, and 365 00:20:00,160 --> 00:20:02,919 Speaker 1: this source came to be known as signus X one, 366 00:20:03,200 --> 00:20:06,720 Speaker 1: and unlike the X ray sources that emitted like regular 367 00:20:06,840 --> 00:20:10,440 Speaker 1: pulses you know sometimes that would happen be be beep, 368 00:20:10,760 --> 00:20:15,159 Speaker 1: Signus X one seemed to be releasing unbelievably powerful, irregular 369 00:20:15,240 --> 00:20:19,640 Speaker 1: bursts of this deadly high frequency radiation, and sometimes these 370 00:20:19,680 --> 00:20:22,560 Speaker 1: irregular bursts were incredibly short, like on the scale of 371 00:20:22,680 --> 00:20:26,040 Speaker 1: millionths of a second, and so at a meeting in 372 00:20:26,200 --> 00:20:31,919 Speaker 1: March ninety one, the Italian astrophysicist Ricardi Giaconi speculated that 373 00:20:31,960 --> 00:20:34,840 Speaker 1: the source of the X one signal might be a 374 00:20:34,960 --> 00:20:39,720 Speaker 1: real black hole, the first black hole apparently observed in space, 375 00:20:40,200 --> 00:20:43,720 Speaker 1: and later analysis did seem to bear out this hypothesis. 376 00:20:43,760 --> 00:20:46,919 Speaker 1: The signus X one system seems to consist of a 377 00:20:47,000 --> 00:20:51,000 Speaker 1: blue giant star orbiting with a much smaller object that 378 00:20:51,119 --> 00:20:54,040 Speaker 1: we can't see. And by observing the size of the 379 00:20:54,040 --> 00:20:56,840 Speaker 1: companion star, the blue giant known as h d E 380 00:20:56,920 --> 00:20:59,960 Speaker 1: two to six six eight, and the rate of its 381 00:21:00,200 --> 00:21:03,040 Speaker 1: orbit it completes an orbit in less than six earth 382 00:21:03,160 --> 00:21:06,919 Speaker 1: days and the size of that orbit, astronomers began to 383 00:21:06,960 --> 00:21:11,080 Speaker 1: get a picture of this unseen orbital center. It appears 384 00:21:11,080 --> 00:21:14,800 Speaker 1: to be invisible, tiny and heavy. Current estimates of its 385 00:21:14,840 --> 00:21:18,520 Speaker 1: mass are at about fourteen point eight of our sons, 386 00:21:18,560 --> 00:21:21,600 Speaker 1: and the radiation coming from this source is emitted as 387 00:21:21,640 --> 00:21:25,639 Speaker 1: this apparent black hole sucks matter off of the orbiting 388 00:21:25,680 --> 00:21:27,720 Speaker 1: star like we were just talking about with the neutron star. 389 00:21:27,760 --> 00:21:30,760 Speaker 1: It sucks gas or matter off of that star, and 390 00:21:30,800 --> 00:21:34,560 Speaker 1: the matter swirls down into the gravity pit of this object, 391 00:21:34,920 --> 00:21:37,359 Speaker 1: heating up as it does, and eventually it heats to 392 00:21:37,400 --> 00:21:40,080 Speaker 1: the point that it gives off X rays, and of course, 393 00:21:40,160 --> 00:21:43,679 Speaker 1: once that gas falls past the event horizon, presumably nothing 394 00:21:43,720 --> 00:21:46,919 Speaker 1: more is emitted. It's stuck inside. But you've got so 395 00:21:46,960 --> 00:21:51,360 Speaker 1: you've got these observations. It's massive, it's tiny, it's invisible, 396 00:21:51,640 --> 00:21:54,560 Speaker 1: and it shoots radiation out into space as it appears 397 00:21:54,600 --> 00:21:58,320 Speaker 1: to suck matter from neighboring bodies. Really really seems like 398 00:21:58,320 --> 00:22:02,000 Speaker 1: a black hole. But was it proof? This was actually 399 00:22:02,160 --> 00:22:05,600 Speaker 1: famously the subject of a bet between physicist Stephen Hawking, 400 00:22:06,280 --> 00:22:08,600 Speaker 1: who did plenty of his own important work on black 401 00:22:08,640 --> 00:22:11,480 Speaker 1: holes in Kip Thorn in nineteen seventy four. Real quick 402 00:22:11,600 --> 00:22:15,680 Speaker 1: Kip Thorne, by the way, not only physicists, but executive 403 00:22:15,720 --> 00:22:19,160 Speaker 1: producer of the two thousand fourteen film Interstellar. Oh yeah, 404 00:22:19,240 --> 00:22:22,600 Speaker 1: that that was probably the best black hole movie I've seen. Yeah, 405 00:22:22,680 --> 00:22:26,120 Speaker 1: and that's why. Right, So he tried to get them 406 00:22:26,160 --> 00:22:29,080 Speaker 1: to like get the science right, Yeah, to say, be accurate, 407 00:22:29,200 --> 00:22:31,240 Speaker 1: make it look like a black hole would really look 408 00:22:31,320 --> 00:22:33,720 Speaker 1: Let's do some math. Yeah, and they did the math, 409 00:22:33,800 --> 00:22:36,520 Speaker 1: and that's a that's that's that's something that most people 410 00:22:36,520 --> 00:22:39,800 Speaker 1: tend to to praise Interstellar for as being the best 411 00:22:40,080 --> 00:22:44,199 Speaker 1: depiction of a black hole in at least cinematic science fiction. Well, 412 00:22:44,320 --> 00:22:46,159 Speaker 1: as I've said on the show before, my favorite thing 413 00:22:46,160 --> 00:22:48,160 Speaker 1: about it is how it actually deals with the time 414 00:22:48,200 --> 00:22:52,159 Speaker 1: dilation effects of relativity. Uh. Yeah, there's a lot to 415 00:22:52,240 --> 00:22:54,800 Speaker 1: like about Interstellar. But coming back to that bet. I'm 416 00:22:54,800 --> 00:22:56,480 Speaker 1: sure you've heard about this bet before. This is a 417 00:22:56,520 --> 00:23:00,600 Speaker 1: famous bet in the history of physics astrophysics. So Thorn 418 00:23:00,640 --> 00:23:04,040 Speaker 1: and Hawking had this bet. Hawking was the pessimist, Thorn 419 00:23:04,200 --> 00:23:06,719 Speaker 1: was the optimist. Well, I guess depending on what you 420 00:23:06,720 --> 00:23:09,800 Speaker 1: think you know regarding the nature of black holes, right, 421 00:23:10,119 --> 00:23:12,760 Speaker 1: Thorn bet that Signals X one would turn out to 422 00:23:12,760 --> 00:23:15,080 Speaker 1: be a black hole. Hawking bet that it would not 423 00:23:15,200 --> 00:23:17,760 Speaker 1: turn out to be a black hole, and Hawking was wrong. 424 00:23:18,160 --> 00:23:21,840 Speaker 1: By Hawking admitted that the evidence for X one's black 425 00:23:21,880 --> 00:23:24,800 Speaker 1: hole status was so strong that he had to concede 426 00:23:24,800 --> 00:23:26,880 Speaker 1: the bet. So we live in a world now where 427 00:23:26,880 --> 00:23:31,200 Speaker 1: astronomers and astrophysicists are almost totally convinced that black holes exist. 428 00:23:31,680 --> 00:23:34,320 Speaker 1: You can fly out into space in theory, and you 429 00:23:34,359 --> 00:23:38,359 Speaker 1: could fly right into them, but they nevertheless remain tricky 430 00:23:38,440 --> 00:23:41,800 Speaker 1: from an observational standpoint. So I think now for the 431 00:23:41,800 --> 00:23:44,040 Speaker 1: rest of the episode, we should try to explain some 432 00:23:44,160 --> 00:23:46,720 Speaker 1: of the ways that we can use to try to 433 00:23:46,760 --> 00:23:50,400 Speaker 1: detect black holes in space. Yeah, a thing that by 434 00:23:50,400 --> 00:23:55,080 Speaker 1: its very definition cannot be seen, cannot be seen directly, 435 00:23:55,480 --> 00:23:57,440 Speaker 1: of what are the ways in which we can observe 436 00:23:57,480 --> 00:24:00,080 Speaker 1: their presence? Right? Because one of the very things that 437 00:24:00,160 --> 00:24:02,680 Speaker 1: makes a black hole unique is that it neither emits 438 00:24:02,760 --> 00:24:05,680 Speaker 1: nor reflects detectable light of its own. So how would 439 00:24:05,680 --> 00:24:08,160 Speaker 1: we ever know if it one exists? Well, there are 440 00:24:08,160 --> 00:24:11,000 Speaker 1: lots of indirect ways of detecting them. And of course, 441 00:24:11,080 --> 00:24:13,359 Speaker 1: even though it doesn't emit light of its own, that 442 00:24:13,400 --> 00:24:16,240 Speaker 1: doesn't mean it's necessarily dark, because, as we explained in 443 00:24:16,280 --> 00:24:19,199 Speaker 1: the last episode, there's stuff going on around it. And 444 00:24:19,240 --> 00:24:21,520 Speaker 1: in fact, we just touched on one example of this. 445 00:24:21,920 --> 00:24:25,360 Speaker 1: Uh of the idea of stuff falling into the black hole, 446 00:24:25,400 --> 00:24:28,680 Speaker 1: stuff being material being sucked into it. Yeah, so black 447 00:24:28,720 --> 00:24:32,439 Speaker 1: holes themselves are dark, but from our perspective, the region 448 00:24:32,520 --> 00:24:35,320 Speaker 1: around the black hole can be anything. But So imagine 449 00:24:35,920 --> 00:24:38,920 Speaker 1: there's this region of space where we observe extremely hot, 450 00:24:39,000 --> 00:24:42,120 Speaker 1: high energy radiation. You've got X rays spewing out all 451 00:24:42,119 --> 00:24:44,760 Speaker 1: over the place. What's going on there? Well, a good 452 00:24:44,840 --> 00:24:48,040 Speaker 1: chances you've got a black hole with matter falling into it. 453 00:24:48,359 --> 00:24:50,679 Speaker 1: The matter gets heated up to hundreds of millions of 454 00:24:50,720 --> 00:24:53,960 Speaker 1: degrees and produces all these kinds of powerful radiation that 455 00:24:54,040 --> 00:24:58,120 Speaker 1: are visible from Earth until it passes that threshold, however, 456 00:24:58,200 --> 00:25:00,760 Speaker 1: and falls into the black hole, after which admits nothing. 457 00:25:01,240 --> 00:25:04,359 Speaker 1: To revisit what we uh the example I brought up 458 00:25:04,359 --> 00:25:05,919 Speaker 1: in the last episode, I think it's kind of like 459 00:25:05,920 --> 00:25:08,119 Speaker 1: you've got a haunted house and you've got like a 460 00:25:08,119 --> 00:25:11,159 Speaker 1: car that takes people around the haunted house. And the 461 00:25:11,200 --> 00:25:13,919 Speaker 1: car is soundproof, so you can't hear people screams from 462 00:25:14,000 --> 00:25:17,000 Speaker 1: inside the car, but as the tourists line up to 463 00:25:17,119 --> 00:25:19,600 Speaker 1: get into the car, you will probably hear them doing 464 00:25:19,600 --> 00:25:22,440 Speaker 1: all kinds of things as they're like sort of loading in. 465 00:25:22,960 --> 00:25:25,399 Speaker 1: And the fact that you can observe. Often all of 466 00:25:25,440 --> 00:25:28,439 Speaker 1: this violence and radiation around a black hole came up 467 00:25:28,440 --> 00:25:31,760 Speaker 1: in that darkness visible presentation. Right. Yeah, it was pointed 468 00:25:31,800 --> 00:25:34,720 Speaker 1: out that the despite they're inherent darkness, black holes are 469 00:25:34,720 --> 00:25:38,800 Speaker 1: among the brightest objects and the cosmos often, uh pinpointed 470 00:25:38,880 --> 00:25:42,240 Speaker 1: is points of extreme brightness in a relatively compact region 471 00:25:42,280 --> 00:25:44,399 Speaker 1: of space. And this is due to all of the 472 00:25:45,160 --> 00:25:48,840 Speaker 1: material and light surging in and orbiting around the objects 473 00:25:48,840 --> 00:25:51,840 Speaker 1: of the horizon, the point again at which even light 474 00:25:51,880 --> 00:25:56,200 Speaker 1: cannot escape. Right, this is probably a terrible, a terrible comparison. 475 00:25:56,240 --> 00:25:58,240 Speaker 1: But to come back to the Texas chainsaw mask your house, 476 00:25:58,280 --> 00:26:01,160 Speaker 1: it's like, oh again, yeah, they're all the is, all 477 00:26:01,200 --> 00:26:04,439 Speaker 1: these missing teenagers and all of these looted graveyards. Uh. 478 00:26:04,520 --> 00:26:07,560 Speaker 1: And then we have this one area here, uh clear, 479 00:26:07,600 --> 00:26:09,800 Speaker 1: look at all this activity around the house. That's how 480 00:26:09,840 --> 00:26:12,320 Speaker 1: we have some idea about what's going on inside it. Right, 481 00:26:12,400 --> 00:26:14,760 Speaker 1: Maybe you can't get a warrant to go inside the house, 482 00:26:14,840 --> 00:26:17,040 Speaker 1: but you can see there's a ruckus going on or 483 00:26:17,119 --> 00:26:19,440 Speaker 1: in the general vicinity, right, And that's what we're looking 484 00:26:19,440 --> 00:26:21,560 Speaker 1: at here, the black hole ruckus. But that's not the 485 00:26:21,600 --> 00:26:24,800 Speaker 1: only way that we can we can detect the presence 486 00:26:24,800 --> 00:26:26,760 Speaker 1: of a black hole. No, there are lots of other 487 00:26:26,840 --> 00:26:30,520 Speaker 1: really interesting ways. So here's another one. Imagine you are 488 00:26:30,560 --> 00:26:33,560 Speaker 1: to look at a place in the galaxy where visible 489 00:26:33,640 --> 00:26:38,280 Speaker 1: objects are acting weird. Planets are stars travel in these 490 00:26:38,320 --> 00:26:42,040 Speaker 1: repeating loops as if in orbit around something, but we 491 00:26:42,200 --> 00:26:44,600 Speaker 1: can't see what that thing is for them to be 492 00:26:44,640 --> 00:26:47,080 Speaker 1: an orbit around, or if we can see it, maybe 493 00:26:47,080 --> 00:26:49,840 Speaker 1: it's like they're orbiting an invisible star, or we can 494 00:26:49,920 --> 00:26:53,320 Speaker 1: see something very bright that they're orbiting, and the way 495 00:26:53,359 --> 00:26:56,760 Speaker 1: that they're orbiting it indicates that this thing they're orbiting 496 00:26:56,880 --> 00:27:00,880 Speaker 1: might be both very very small and very very massive. 497 00:27:01,320 --> 00:27:04,119 Speaker 1: It's essentially the invisible man scenario, you know, like you 498 00:27:04,160 --> 00:27:06,960 Speaker 1: can see the hat, but there's no person there. Well, 499 00:27:07,000 --> 00:27:09,080 Speaker 1: something must be holding up the hat. Yeah, something's hold 500 00:27:09,119 --> 00:27:11,840 Speaker 1: up the hat and the umbrella. So, uh, for example, 501 00:27:12,280 --> 00:27:14,240 Speaker 1: what do we see when we look closely at the 502 00:27:14,280 --> 00:27:17,320 Speaker 1: center of our own Milky Way galaxy? We mentioned this 503 00:27:17,400 --> 00:27:20,240 Speaker 1: darkness visible presentation at the World Science Festival this year. 504 00:27:20,840 --> 00:27:24,679 Speaker 1: Uh So that presentation featured, among others, the u c 505 00:27:24,840 --> 00:27:28,359 Speaker 1: l A astronomer Andrea Gays, who has spent her career 506 00:27:28,480 --> 00:27:31,919 Speaker 1: examining exactly this question. What's going on at the center 507 00:27:31,960 --> 00:27:34,560 Speaker 1: of the galaxy. Now, of course, we mentioned in the 508 00:27:34,600 --> 00:27:37,840 Speaker 1: previous episode and earlier today that researchers have come to 509 00:27:37,880 --> 00:27:41,080 Speaker 1: believe that there is a supermassive black hole at the 510 00:27:41,119 --> 00:27:44,240 Speaker 1: center of most are all mature galaxies, and our galaxy 511 00:27:44,280 --> 00:27:46,680 Speaker 1: is no different. At the center of our galaxy, there's 512 00:27:46,720 --> 00:27:50,320 Speaker 1: an object called Sagittary Essay, which is believed to be 513 00:27:50,560 --> 00:27:53,840 Speaker 1: a black hole about four point three million times the 514 00:27:53,880 --> 00:27:56,720 Speaker 1: mass of our Sun, though Gays actually says that this 515 00:27:56,800 --> 00:27:59,680 Speaker 1: is on the low end of supermassive black holes, which 516 00:27:59,720 --> 00:28:02,239 Speaker 1: can be up to a billion times the mass of 517 00:28:02,240 --> 00:28:05,200 Speaker 1: our son. Though I want, I want to be impressed 518 00:28:05,240 --> 00:28:07,920 Speaker 1: by that, but I'm running into like the scale problem 519 00:28:08,040 --> 00:28:11,720 Speaker 1: right where somebody says like, hey, Robert, I want to 520 00:28:11,760 --> 00:28:16,000 Speaker 1: give you a hundred billion dollars or I want to 521 00:28:16,040 --> 00:28:19,960 Speaker 1: give you five hundred billion dollars. Yeah, up saying with 522 00:28:20,040 --> 00:28:22,080 Speaker 1: the scales that they might as well be the same 523 00:28:22,160 --> 00:28:25,679 Speaker 1: number because they're just so beyond my ability to, you know, 524 00:28:25,720 --> 00:28:27,920 Speaker 1: to fit them within the confines of my own life. Yeah, 525 00:28:27,960 --> 00:28:29,840 Speaker 1: what does that mean? What does that difference even matter? 526 00:28:30,160 --> 00:28:32,680 Speaker 1: What am I supposed to do with that information? Yeah? 527 00:28:32,720 --> 00:28:35,560 Speaker 1: So even though I recognize that that is a big difference, 528 00:28:35,600 --> 00:28:38,760 Speaker 1: and that that's it should be really impressive. I can't 529 00:28:38,760 --> 00:28:41,640 Speaker 1: actually picture it, so I'm I'm kind of stuck there. 530 00:28:41,960 --> 00:28:43,760 Speaker 1: You often run into this with some of the most 531 00:28:43,800 --> 00:28:46,960 Speaker 1: impressive stuff, and in astronomy it's like you want to 532 00:28:47,000 --> 00:28:51,920 Speaker 1: be accurately appreciative, but you can't visualize the scale. Yeah, 533 00:28:51,920 --> 00:28:55,080 Speaker 1: because then the numbers just become meaningless to most minds 534 00:28:55,120 --> 00:28:57,600 Speaker 1: after a point. But anyway, back to so Sagittary is, 535 00:28:57,600 --> 00:29:00,000 Speaker 1: say this thing that we believe to be a super 536 00:29:00,040 --> 00:29:03,120 Speaker 1: supermassive black hole. How how would you detect if it 537 00:29:03,160 --> 00:29:05,960 Speaker 1: really were a supermassive black hole? And just to note, 538 00:29:06,200 --> 00:29:09,120 Speaker 1: we keep calling it Sagittarius A, but technically the object 539 00:29:09,120 --> 00:29:12,280 Speaker 1: believed to be the black hole is Sagittarius A with 540 00:29:12,360 --> 00:29:16,640 Speaker 1: little asterisks. They call that Sagittarius A star. While Sagittarius 541 00:29:16,680 --> 00:29:19,160 Speaker 1: A as a whole is this more complex source of 542 00:29:19,280 --> 00:29:22,800 Speaker 1: radio signals, including the object we're talking about. So technically 543 00:29:22,800 --> 00:29:25,600 Speaker 1: it's Sagittarius A star, but I think we will keep 544 00:29:25,600 --> 00:29:29,360 Speaker 1: calling it Sagittarius A because when you're also talking about stars, 545 00:29:29,520 --> 00:29:32,680 Speaker 1: saying a star over and over can be confusing. So 546 00:29:32,840 --> 00:29:36,280 Speaker 1: the main method that Gaye talks about is to demonstrate 547 00:29:36,320 --> 00:29:39,560 Speaker 1: that a mass is within its short shield radius. We 548 00:29:39,600 --> 00:29:42,160 Speaker 1: talked about the short shield sphere in the last episode, 549 00:29:42,560 --> 00:29:45,800 Speaker 1: and in simple terms, what you're looking for is big mass, 550 00:29:45,960 --> 00:29:49,720 Speaker 1: small volume. We know that any mass contained within the 551 00:29:49,840 --> 00:29:53,800 Speaker 1: volume of its short shield radius will inevitably collapse into 552 00:29:53,840 --> 00:29:57,000 Speaker 1: a black hole. Nothing can stop it. At this scale, 553 00:29:57,240 --> 00:30:00,840 Speaker 1: gravity always wins, and a if you can show this, 554 00:30:00,960 --> 00:30:03,160 Speaker 1: if you can show that an object is of a 555 00:30:03,200 --> 00:30:06,760 Speaker 1: mass that's within the volume of its short shield radius, 556 00:30:07,000 --> 00:30:10,240 Speaker 1: you've effectively demonstrated that it must be a black hole. 557 00:30:10,720 --> 00:30:12,880 Speaker 1: So to see what's happening at the center of our galaxy, 558 00:30:12,920 --> 00:30:16,320 Speaker 1: we can look toward the constellation Sagittarius, and if you 559 00:30:16,320 --> 00:30:18,440 Speaker 1: have the right kind of telescope, you can peer straight 560 00:30:18,440 --> 00:30:21,000 Speaker 1: through to the group of stars at the core of 561 00:30:21,040 --> 00:30:24,520 Speaker 1: the Milky Way, the galactic center. And these stars really 562 00:30:24,560 --> 00:30:27,800 Speaker 1: do behave in an odd way, especially like a central 563 00:30:27,840 --> 00:30:32,120 Speaker 1: star called s O two, which orbits the object Sagittarius 564 00:30:32,160 --> 00:30:35,120 Speaker 1: A in a pattern of one orbit every sixteen years. 565 00:30:35,480 --> 00:30:37,719 Speaker 1: There are animations of this that are worth looking up. 566 00:30:37,760 --> 00:30:40,240 Speaker 1: In fact, there's even direct imaging. I don't know, but 567 00:30:40,320 --> 00:30:42,520 Speaker 1: it might be infrared imaging. But they're there. You can 568 00:30:42,560 --> 00:30:45,560 Speaker 1: like see the stars actually moving over a long time 569 00:30:45,640 --> 00:30:48,320 Speaker 1: lapse video, and the path of s O two looks 570 00:30:48,320 --> 00:30:51,280 Speaker 1: almost like a I'm trying to find the right point 571 00:30:51,280 --> 00:30:53,880 Speaker 1: of comparison. It's sort of like a pendulum or something, 572 00:30:53,960 --> 00:30:56,840 Speaker 1: you know, where you see something kind of slowly go 573 00:30:57,120 --> 00:30:59,760 Speaker 1: up to one side and then zoom down along the 574 00:30:59,800 --> 00:31:03,200 Speaker 1: other side. Um. And so that's what happens with the 575 00:31:03,280 --> 00:31:06,720 Speaker 1: start cruises slowly through a lot of its elliptical path 576 00:31:07,080 --> 00:31:09,960 Speaker 1: and then whips lightning fast through one end of the 577 00:31:10,000 --> 00:31:12,880 Speaker 1: ellipse of its orbit. And what's going on there is 578 00:31:12,920 --> 00:31:16,240 Speaker 1: apparently when s O two travels through the closest part 579 00:31:16,240 --> 00:31:20,480 Speaker 1: of its orbit with Sagittarius AY about seventeen light hours away, 580 00:31:20,680 --> 00:31:23,280 Speaker 1: it's moving at about three percent of the speed of light, 581 00:31:23,520 --> 00:31:28,040 Speaker 1: or roughly thirty million kilometers per hour, and that even 582 00:31:28,080 --> 00:31:30,240 Speaker 1: if you just look at the animations, you can tell 583 00:31:30,280 --> 00:31:33,959 Speaker 1: it's super fast. So because we can image the region 584 00:31:33,960 --> 00:31:37,920 Speaker 1: of Sagittarius AY and the objects traveling around Sagittarius A, 585 00:31:38,280 --> 00:31:41,400 Speaker 1: we can do physics calculations to determine the size and 586 00:31:41,440 --> 00:31:43,920 Speaker 1: the mass of what this object is, and it turns 587 00:31:43,920 --> 00:31:46,640 Speaker 1: out that it's more than four million times the mass 588 00:31:46,640 --> 00:31:49,280 Speaker 1: of our sun and appears to be crammed into this 589 00:31:49,480 --> 00:31:52,080 Speaker 1: very very tiny region at the center of the galaxy. 590 00:31:52,160 --> 00:31:55,400 Speaker 1: So it looks very much like a supermassive black hole. 591 00:31:55,720 --> 00:31:57,520 Speaker 1: All Right, we're gonna take one more break and we 592 00:31:57,600 --> 00:32:00,280 Speaker 1: come back. We will jump into more ways that we 593 00:32:00,360 --> 00:32:07,480 Speaker 1: detect black holes, including gravitational lensing. Thank thank Alright, we're back, Hey, Robert, 594 00:32:07,960 --> 00:32:10,320 Speaker 1: So what would happen do you think if you were 595 00:32:10,440 --> 00:32:14,920 Speaker 1: looking at something and a black hole passed between you 596 00:32:15,040 --> 00:32:18,000 Speaker 1: and the thing you were looking at. Ah? Well, I 597 00:32:18,040 --> 00:32:21,160 Speaker 1: think on one hand, a lot of people are attempted 598 00:32:21,200 --> 00:32:23,200 Speaker 1: to say, oh, you wouldn't be able to see it, 599 00:32:23,240 --> 00:32:25,000 Speaker 1: because the black hole would be in the way. It'd 600 00:32:25,000 --> 00:32:27,200 Speaker 1: be opaque. It would be like taking a black piece 601 00:32:27,240 --> 00:32:31,080 Speaker 1: of paper across your field division just blotted out. But 602 00:32:31,680 --> 00:32:35,120 Speaker 1: that doesn't quite seem to be the case. Definitely, not necessarily. 603 00:32:35,680 --> 00:32:39,200 Speaker 1: What occurs is something called gravitational lensing, and this occurs 604 00:32:39,240 --> 00:32:43,600 Speaker 1: when a strong gravitational field bends light around it, creating 605 00:32:43,600 --> 00:32:47,440 Speaker 1: a lens like effect, warping and magnifying light coming from 606 00:32:47,480 --> 00:32:50,760 Speaker 1: the opposite direction of the view. Yeah. So the simplified 607 00:32:50,880 --> 00:32:53,080 Speaker 1: version of this, I suspect it wouldn't actually work for 608 00:32:53,120 --> 00:32:56,720 Speaker 1: objects this small. But it's that if you, you know, Robert, 609 00:32:56,720 --> 00:32:58,640 Speaker 1: you and I stand on opposite ends of the room 610 00:32:59,080 --> 00:33:01,760 Speaker 1: and you put a black hole directly between us, instead 611 00:33:01,800 --> 00:33:05,280 Speaker 1: of just being completely blotted out, we'll sort of see weird, 612 00:33:05,640 --> 00:33:10,200 Speaker 1: warped fun house mirror versions of each other wrapped around 613 00:33:10,280 --> 00:33:13,440 Speaker 1: this dark spot. In our field of view. We will 614 00:33:13,480 --> 00:33:18,400 Speaker 1: be essentially distorted through the lens created by the gravity 615 00:33:18,440 --> 00:33:21,480 Speaker 1: distortion of the black hole. Yeah. One example of this 616 00:33:21,560 --> 00:33:25,600 Speaker 1: is frequently um used is what's known as Einstein's cross 617 00:33:26,160 --> 00:33:29,760 Speaker 1: These are four images of the same distant quasar that 618 00:33:29,840 --> 00:33:33,440 Speaker 1: appear around a four ground galaxy due to strong grave 619 00:33:33,720 --> 00:33:37,840 Speaker 1: gravitational lensing. So there's kind of this blur in the center, 620 00:33:38,280 --> 00:33:42,080 Speaker 1: and then the same star is pictured four different places 621 00:33:42,120 --> 00:33:44,920 Speaker 1: around it. That's interesting, So you might think of it 622 00:33:44,960 --> 00:33:47,600 Speaker 1: that way. In our our our rough example, here, I'm 623 00:33:47,600 --> 00:33:50,360 Speaker 1: looking across the room. I see a basic like blur 624 00:33:50,520 --> 00:33:52,560 Speaker 1: where you should be, where the black hole is is 625 00:33:52,600 --> 00:33:55,320 Speaker 1: blocking my view. And then perhaps to either side of you, 626 00:33:55,520 --> 00:33:59,000 Speaker 1: I see distorted versions of Joe, a beautiful image. Yeah, 627 00:33:59,000 --> 00:34:01,080 Speaker 1: maybe one floating a of you as well, kind of 628 00:34:01,080 --> 00:34:05,000 Speaker 1: like an angelic visitor with like kind of crazy warped 629 00:34:05,120 --> 00:34:07,680 Speaker 1: arms flapping around on both sides, like one of those 630 00:34:07,680 --> 00:34:11,239 Speaker 1: inflatable dude dads you see it to use car dealership. 631 00:34:12,320 --> 00:34:15,520 Speaker 1: Another example that I came across was that in two 632 00:34:15,520 --> 00:34:18,719 Speaker 1: thousand and ten, the Keck two telescope in Hawaii and 633 00:34:18,760 --> 00:34:22,919 Speaker 1: it's in I r C two instruments observed a four 634 00:34:23,040 --> 00:34:27,520 Speaker 1: ground quasar causing gravitational lensing of a galaxy in the 635 00:34:27,520 --> 00:34:29,920 Speaker 1: background behind it. So I think it's actually the reverse 636 00:34:30,040 --> 00:34:33,920 Speaker 1: of the example you just gave. So the quaysar is 637 00:34:34,000 --> 00:34:36,960 Speaker 1: likely to be a giant black hole that's spewing huge 638 00:34:36,960 --> 00:34:39,680 Speaker 1: amounts of radiation into the universe around it, making it 639 00:34:39,760 --> 00:34:44,399 Speaker 1: extremely bright. And this foreground quasar is known as sd 640 00:34:44,760 --> 00:34:48,560 Speaker 1: s J zero zero thirteen plus one to three. I 641 00:34:48,560 --> 00:34:50,840 Speaker 1: almost stopped reading there, but you know, you got to 642 00:34:50,840 --> 00:34:53,640 Speaker 1: say all the numbers, uh. And it's about one point 643 00:34:53,640 --> 00:34:56,200 Speaker 1: six billion light years from Earth, so this is very, 644 00:34:56,320 --> 00:34:58,719 Speaker 1: very far away. I included a picture here for us 645 00:34:58,760 --> 00:35:01,600 Speaker 1: to look at, but you can see how the quays 646 00:35:01,640 --> 00:35:05,799 Speaker 1: are in the foreground because of its great gravitational distortion effects, 647 00:35:05,960 --> 00:35:10,239 Speaker 1: seems to create a lensed image. These distorted side effects 648 00:35:10,280 --> 00:35:13,640 Speaker 1: of a galaxy that's in the background right behind it. 649 00:35:14,600 --> 00:35:16,680 Speaker 1: But we should get to the next method because actually, 650 00:35:16,760 --> 00:35:19,080 Speaker 1: I think this is maybe the most interesting and one 651 00:35:19,120 --> 00:35:22,080 Speaker 1: of the most conclusive methods that we have come up 652 00:35:22,080 --> 00:35:25,600 Speaker 1: with so far to demonstrate not only the existence of 653 00:35:25,640 --> 00:35:27,879 Speaker 1: black holes in the universe, but some of the most 654 00:35:28,040 --> 00:35:31,839 Speaker 1: violent black hole behaviors in the known universe. And that 655 00:35:31,960 --> 00:35:34,200 Speaker 1: is finally getting to a world where we can observe 656 00:35:34,200 --> 00:35:38,080 Speaker 1: gravitational waves. That's right, So we already discussed the general 657 00:35:38,160 --> 00:35:42,680 Speaker 1: relativity concept that mass distorts space time. As part of this, 658 00:35:42,719 --> 00:35:46,800 Speaker 1: Einstein also predicted that we'd observed ripples in spacetime gravitational 659 00:35:46,920 --> 00:35:50,600 Speaker 1: waves caused by some of the more extreme occurrences linked 660 00:35:50,640 --> 00:35:55,000 Speaker 1: to massive accelerating objects, like like a massive star being 661 00:35:55,120 --> 00:35:59,680 Speaker 1: hit with God's pool cue what ripping up the fabric 662 00:36:00,600 --> 00:36:03,040 Speaker 1: or just just the shock wave, the sound, you know, 663 00:36:03,080 --> 00:36:04,879 Speaker 1: however you want to, you know, interpret it just the 664 00:36:05,000 --> 00:36:07,360 Speaker 1: violence of the act. Well, you know, one of the 665 00:36:07,360 --> 00:36:11,200 Speaker 1: funny things in the last episode we mentioned the English 666 00:36:11,640 --> 00:36:14,200 Speaker 1: you guess you might call him a poly mauth, John Michelle, 667 00:36:14,200 --> 00:36:16,440 Speaker 1: who was one of the early people to write about 668 00:36:16,440 --> 00:36:18,680 Speaker 1: the idea of something like a black hole and a 669 00:36:18,800 --> 00:36:21,640 Speaker 1: thing that he posited that many people might not have 670 00:36:22,360 --> 00:36:24,400 Speaker 1: been able to imagine at the time, was the idea 671 00:36:24,440 --> 00:36:28,120 Speaker 1: of ripples going through the earth. The earth the like 672 00:36:28,200 --> 00:36:31,400 Speaker 1: earthquakes could be caused by shock waves and the earth 673 00:36:31,480 --> 00:36:35,680 Speaker 1: flexing up and down due to friction events. And so 674 00:36:35,880 --> 00:36:37,799 Speaker 1: you know, it's hard for somebody to imagine, how could 675 00:36:37,800 --> 00:36:40,480 Speaker 1: there be ripples in the ground. The ground is just solid. 676 00:36:40,600 --> 00:36:42,880 Speaker 1: You know, I see waves in water, but surely not 677 00:36:42,960 --> 00:36:46,200 Speaker 1: in the ground. Take this the next step. Take this 678 00:36:46,280 --> 00:36:50,480 Speaker 1: to ripples and waves emanating through the geometry of spacetime itself. 679 00:36:50,880 --> 00:36:53,600 Speaker 1: So what kind of violence would we be talking about here? 680 00:36:53,719 --> 00:36:55,880 Speaker 1: So obviously God doesn't play pool, so we can't go 681 00:36:55,920 --> 00:36:57,800 Speaker 1: with the pool que example as far as you know 682 00:36:58,000 --> 00:37:00,279 Speaker 1: as well. Yes, so he doesn't play it in this 683 00:37:00,440 --> 00:37:02,600 Speaker 1: universe in a way that we can observe it, But 684 00:37:02,800 --> 00:37:07,319 Speaker 1: we can look to other cataclysmic events like supernova and 685 00:37:07,480 --> 00:37:12,440 Speaker 1: colliding black holes. Now, we were not able to observe 686 00:37:12,480 --> 00:37:15,200 Speaker 1: any proof of this until nineteen four and that's when 687 00:37:15,480 --> 00:37:20,040 Speaker 1: astronomers at Aricibo Radio Observatory in Puerto Rico discovered a 688 00:37:20,080 --> 00:37:25,200 Speaker 1: binary pulsar. And then it wasn't until astronomers using the 689 00:37:25,280 --> 00:37:32,600 Speaker 1: Ligo that's a laser interferometer gravitational wave observatory actually physically, 690 00:37:32,640 --> 00:37:37,840 Speaker 1: since gravitational waves emitted by two colliding black holes nearly 691 00:37:38,239 --> 00:37:42,480 Speaker 1: one point three billion light years away billion light years, 692 00:37:42,640 --> 00:37:46,680 Speaker 1: So how could we detect something that far away? Well, 693 00:37:47,120 --> 00:37:49,960 Speaker 1: the whole set up here is really fascinating because when 694 00:37:49,960 --> 00:37:52,480 Speaker 1: you when you look at pictures of it, it does 695 00:37:52,520 --> 00:37:57,240 Speaker 1: not look like a telescope. Uh. They use special detectors 696 00:37:57,280 --> 00:38:02,480 Speaker 1: in at the time to locations Washington State and Louisiana, uh, 697 00:38:02,680 --> 00:38:07,520 Speaker 1: separated Uh, this way across you know, of what, three 698 00:38:07,560 --> 00:38:11,560 Speaker 1: thousand kilometers in order to rule out localized distortions, right, 699 00:38:11,640 --> 00:38:13,880 Speaker 1: So you wouldn't want to rumble in one place to 700 00:38:13,920 --> 00:38:17,440 Speaker 1: give you a false positive on gravitational waves. So what 701 00:38:17,520 --> 00:38:21,879 Speaker 1: these things looked like are two blind l shaped detectors 702 00:38:22,280 --> 00:38:26,880 Speaker 1: with with the four kilometer long vacuum chambers essentially long 703 00:38:26,960 --> 00:38:32,040 Speaker 1: tubes with lasers shining through them, uh, calibrated to detect 704 00:38:32,120 --> 00:38:37,560 Speaker 1: like just just minute motions to measure emotion ten thousand 705 00:38:37,640 --> 00:38:41,919 Speaker 1: times smaller than an atomic nucleus, the smallest measurement ever 706 00:38:41,960 --> 00:38:45,960 Speaker 1: attempted by science. And again this is calibrated to to 707 00:38:46,080 --> 00:38:50,279 Speaker 1: observe these oscillations caused by the most violent and cataclysmic 708 00:38:50,320 --> 00:38:52,600 Speaker 1: events in the universe that are occurring millions or billions 709 00:38:52,600 --> 00:38:57,080 Speaker 1: of light years away. So both detectors picked up on 710 00:38:57,120 --> 00:39:01,200 Speaker 1: the black hole emitted gravitational waves at the expected intervals 711 00:39:01,640 --> 00:39:04,960 Speaker 1: dancing black holes in another galaxy, and then the waves 712 00:39:04,960 --> 00:39:07,880 Speaker 1: stop as the merger becomes absolute. Is the two black 713 00:39:07,880 --> 00:39:10,680 Speaker 1: holes stop dancing and become one. Okay, So you've got 714 00:39:10,680 --> 00:39:14,880 Speaker 1: this picture created by these two different laser observatories at 715 00:39:14,920 --> 00:39:18,279 Speaker 1: different parts of the country that something happened very very 716 00:39:18,320 --> 00:39:21,560 Speaker 1: far away where suddenly there was this escalating ripple as 717 00:39:21,600 --> 00:39:24,400 Speaker 1: these black holes kind of swirled into each other and 718 00:39:24,400 --> 00:39:28,239 Speaker 1: then merged and then boom nothing right, And that's exactly 719 00:39:28,280 --> 00:39:31,720 Speaker 1: what they expected to find. That the results match simulations 720 00:39:32,000 --> 00:39:35,680 Speaker 1: and therefore expectations the basic template for black hole merger. 721 00:39:35,880 --> 00:39:38,439 Speaker 1: And because they've got these two different stations, they could 722 00:39:38,480 --> 00:39:41,919 Speaker 1: say with really good confidence that they know this really 723 00:39:41,960 --> 00:39:44,120 Speaker 1: came from space and what it really is. It wasn't 724 00:39:44,160 --> 00:39:46,360 Speaker 1: just some kind of local fluke. Yeah, or you know, 725 00:39:46,400 --> 00:39:48,680 Speaker 1: like a car driving by with its stereo turned up right. 726 00:39:49,080 --> 00:39:52,319 Speaker 1: Uh No, Jack Burton and his rig uh. And And 727 00:39:52,360 --> 00:39:54,640 Speaker 1: since that time we've added there's they've added a less 728 00:39:54,640 --> 00:39:57,960 Speaker 1: sensitive Italian telescope into the mix and have observed waves 729 00:39:57,960 --> 00:40:01,879 Speaker 1: generated by a pair of neutron stars as well. Now, 730 00:40:01,920 --> 00:40:04,799 Speaker 1: when you were talking to Brian Green, the physicist at 731 00:40:04,840 --> 00:40:07,239 Speaker 1: the World Science Festival, and you asked him what the 732 00:40:07,280 --> 00:40:10,640 Speaker 1: most interesting research frontier and experimental physics was today, he 733 00:40:10,719 --> 00:40:14,880 Speaker 1: named gravitational waves because he basically said that this opens 734 00:40:14,960 --> 00:40:18,240 Speaker 1: up a whole new way of looking at the universe 735 00:40:18,280 --> 00:40:20,560 Speaker 1: that we did not have before, and so there are 736 00:40:20,560 --> 00:40:23,640 Speaker 1: all kinds of surprises we could discover through it. Yeah, 737 00:40:23,680 --> 00:40:25,479 Speaker 1: I mean in a in a in a weird way. 738 00:40:25,560 --> 00:40:29,280 Speaker 1: And it's almost like we're suddenly able to to listen 739 00:40:29,280 --> 00:40:32,320 Speaker 1: to the pulse of of of things in the universe 740 00:40:32,360 --> 00:40:36,080 Speaker 1: that were previously silent to us but that we suspected 741 00:40:36,200 --> 00:40:38,560 Speaker 1: would be present. I like that, And so that brings 742 00:40:38,640 --> 00:40:41,640 Speaker 1: us back, That brings us up to that that basically 743 00:40:41,640 --> 00:40:44,520 Speaker 1: brings us up to the present. Now, that's definitely not everything. 744 00:40:44,520 --> 00:40:46,640 Speaker 1: I mean, there's all kinds of interesting work that's been 745 00:40:46,680 --> 00:40:48,719 Speaker 1: done in the years in between on black holes, like 746 00:40:48,719 --> 00:40:51,360 Speaker 1: all the work of Stephen Hawking and everything, but um 747 00:40:51,480 --> 00:40:56,240 Speaker 1: Hawking radiation and entropy and information loss and uh and stuff. 748 00:40:56,239 --> 00:40:59,320 Speaker 1: And so I think we in the next episode should 749 00:40:59,440 --> 00:41:03,600 Speaker 1: explore a little bit of the weirder side and outstanding 750 00:41:03,680 --> 00:41:07,440 Speaker 1: mysteries about black holes, questions that are as yet unsolved, 751 00:41:07,880 --> 00:41:11,319 Speaker 1: or the weirdest thought experiments about black holes. Oh yes, 752 00:41:11,320 --> 00:41:13,879 Speaker 1: because that's the that's the wonderful part, right. Black holes 753 00:41:13,880 --> 00:41:18,880 Speaker 1: began as thought experiments, and thought experiments concerning black holes continue. 754 00:41:19,200 --> 00:41:21,759 Speaker 1: So black holes already maybe the weirdest thing in the 755 00:41:21,880 --> 00:41:24,759 Speaker 1: universe that's not alive. And in the next episode we're 756 00:41:24,760 --> 00:41:26,880 Speaker 1: going to find out what are the weirdest things about 757 00:41:26,920 --> 00:41:29,520 Speaker 1: them and the biggest mysteries yet unsolved. That's right. And 758 00:41:29,560 --> 00:41:32,160 Speaker 1: I'm also going to try and rewatch Event Horizon before 759 00:41:32,200 --> 00:41:36,200 Speaker 1: that episode as well. Prepare for leather punk Spaceship. Yeah, 760 00:41:36,520 --> 00:41:39,680 Speaker 1: and and I can truly, I can truly say where 761 00:41:39,680 --> 00:41:42,040 Speaker 1: we're going. You won't need eyes to see because it's 762 00:41:42,040 --> 00:41:44,560 Speaker 1: a podcast, you really don't have to to see anything. 763 00:41:44,680 --> 00:41:47,200 Speaker 1: And because it's a black hole and no light escapes exactly, 764 00:41:47,560 --> 00:41:50,200 Speaker 1: it all fits together. It's a great script that Event 765 00:41:50,239 --> 00:41:54,399 Speaker 1: Horizon alright. In the meantime, head on over to Stuff 766 00:41:54,440 --> 00:41:56,680 Speaker 1: to Blow your Mind dot com. That is the mothership. 767 00:41:56,719 --> 00:41:58,719 Speaker 1: That's where we'll find all the episodes of the podcast, 768 00:41:58,800 --> 00:42:01,440 Speaker 1: as well as links out to our us social media accounts. 769 00:42:01,719 --> 00:42:03,760 Speaker 1: As always, I urge you if you want to support 770 00:42:03,800 --> 00:42:05,840 Speaker 1: this podcast, A great way to do it is to 771 00:42:06,080 --> 00:42:09,319 Speaker 1: rate and review us wherever you can, especially wherever you 772 00:42:09,360 --> 00:42:13,760 Speaker 1: actually obtain the podcast. Thanks as always to our wonderful 773 00:42:13,800 --> 00:42:17,480 Speaker 1: audio producers Alex Williams and Tory Harrison. If you would 774 00:42:17,520 --> 00:42:19,080 Speaker 1: like to get in touch with us to let us 775 00:42:19,080 --> 00:42:22,120 Speaker 1: know feedback on this episode or any other, to let 776 00:42:22,200 --> 00:42:24,120 Speaker 1: us know a topic you might let us like us 777 00:42:24,120 --> 00:42:26,120 Speaker 1: to cover in the future, or just to say hi, 778 00:42:26,239 --> 00:42:28,440 Speaker 1: let us know where you listen from. You can always 779 00:42:28,440 --> 00:42:31,120 Speaker 1: email us at blow the Mind at how stuff works 780 00:42:31,200 --> 00:42:42,840 Speaker 1: dot com for more on this and thousands of other topics. 781 00:42:43,080 --> 00:43:04,600 Speaker 1: Is it how stuff works dot com proper Postschi Baba