1 00:00:00,160 --> 00:00:03,000 Speaker 1: Welcome to Thrilling Threads, the show where we stitch together 2 00:00:03,080 --> 00:00:06,240 the wildest, most profound ideas hiding in the sources you 3 00:00:06,240 --> 00:00:06,879 share with us. 4 00:00:07,040 --> 00:00:12,039 Speaker 2: Today we are diving into a real crisis point in physics. 5 00:00:11,960 --> 00:00:16,359 Speaker 1: A moment of profound, i'd say, mathematical terror. The greatest 6 00:00:16,440 --> 00:00:19,719 minds of the twentieth century were well, they were teetering 7 00:00:19,760 --> 00:00:21,160 on the edge of utter despair. 8 00:00:21,399 --> 00:00:25,000 Speaker 2: And all this chaos was triggered by one quiet, unassuming man, 9 00:00:25,239 --> 00:00:26,440 Paul de Raq, and. 10 00:00:26,399 --> 00:00:31,399 Speaker 1: One tiny, yet absolutely terrifying mathematical sign, the simple negative sign. 11 00:00:31,600 --> 00:00:35,000 Speaker 2: It's really hard to overstate the dramatic tension of nineteen 12 00:00:35,039 --> 00:00:38,439 twenty eight. Quantum mechanics was revolutionary, but it was still fragile, 13 00:00:38,560 --> 00:00:38,759 you know. 14 00:00:39,000 --> 00:00:42,159 Speaker 1: Right, and into the scene walks this young, reserved theorist 15 00:00:42,240 --> 00:00:45,200 Paul Durak, presenting his work at a lecture in Germany. 16 00:00:45,320 --> 00:00:48,679 Speaker 2: By all accounts, his presentation style was well technical, precise, 17 00:00:48,719 --> 00:00:51,520 and just utterly devoid of any passion or flourish. 18 00:00:51,600 --> 00:00:54,560 Speaker 1: Yeah. I read that. One physicist Eugene Wigner described the 19 00:00:54,560 --> 00:00:57,359 scene saying direct delivered his lecture without giving any sign 20 00:00:57,439 --> 00:00:59,840 of enjoying his own lecture, almost like he was just 21 00:01:00,079 --> 00:01:01,640 citing facts he found self. 22 00:01:01,439 --> 00:01:04,480 Speaker 2: Evident, and the scientific elite, I mean, the people who 23 00:01:04,560 --> 00:01:07,079 had built quantum mechanics, they reacted as if he'd just 24 00:01:07,120 --> 00:01:09,640 announced the foundations of reality were rotten. 25 00:01:10,079 --> 00:01:12,959 Speaker 1: Our sources paint a pretty visit picture of the fallout. 26 00:01:13,359 --> 00:01:17,120 Werner Heisenberg, you know, the guy famous for the uncertainty principle. 27 00:01:17,560 --> 00:01:21,439 He dismissed the theory as the saddest chapter in modern physics. 28 00:01:21,719 --> 00:01:24,879 Speaker 2: He was so frustrated by the mathematical paradox that he 29 00:01:24,920 --> 00:01:28,120 actually wrote a letter to his mentor, Neils Bohrer and 30 00:01:28,400 --> 00:01:32,239 confessed his despair. He said, I find the present situation 31 00:01:32,439 --> 00:01:35,599 quite absurd, and on that account, almost out of despair, 32 00:01:35,680 --> 00:01:37,040 I have taken up another field. 33 00:01:37,400 --> 00:01:39,159 Speaker 1: He was ready to quit, he was. 34 00:01:39,879 --> 00:01:41,799 Speaker 2: The community was genuinely shaken. 35 00:01:42,079 --> 00:01:45,040 Speaker 1: And there's that great anecdotebout Wolfgang Polly, who was known 36 00:01:45,040 --> 00:01:47,680 for being the sharpest, most critical mind in the field, 37 00:01:48,000 --> 00:01:51,120 the one who would just verbally dismantle any flawed theory, 38 00:01:51,280 --> 00:01:54,079 right the conscience of physics exactly. And legend has it 39 00:01:54,120 --> 00:01:57,239 that Polly was so disturbed by the result direct presented, 40 00:01:57,280 --> 00:02:01,120 this result that made zero physical sense, that he abandoned 41 00:02:01,159 --> 00:02:02,280 quantum physics. 42 00:02:01,959 --> 00:02:05,079 Speaker 2: Entirely and decided to spend his time writing a utopian 43 00:02:05,120 --> 00:02:05,799 novel instead. 44 00:02:06,120 --> 00:02:09,360 Speaker 1: I mean, that's the level of intellectual crisis we're talking about. 45 00:02:09,560 --> 00:02:12,560 The math is beautiful, but the reality it describes seems 46 00:02:12,599 --> 00:02:13,919 completely impossible. 47 00:02:14,080 --> 00:02:16,479 Speaker 2: And that's the high stakes environment we're investigating today. 48 00:02:16,719 --> 00:02:20,759 Speaker 1: So what was the bombshell? What was this seemingly absurd 49 00:02:20,840 --> 00:02:23,400 prediction that triggered such a complete breakdown. 50 00:02:23,599 --> 00:02:27,560 Speaker 2: It was the unavoidable mathematical requirement for a particle with 51 00:02:27,960 --> 00:02:30,039 of all things, negative energy. 52 00:02:30,319 --> 00:02:33,800 Speaker 1: So our mission in this thrilling threads deep dive is 53 00:02:33,840 --> 00:02:37,240 to trace that high stakes quest to unite the two 54 00:02:37,479 --> 00:02:42,599 monumental achievements of early twentieth century physics, Einstein's special relativity 55 00:02:42,800 --> 00:02:44,159 and quantum mechanics, and. 56 00:02:44,120 --> 00:02:48,240 Speaker 2: We'll unpack how Directs well almost religious pursuit of mathematical beauty, 57 00:02:48,759 --> 00:02:52,120 forced physics to accept the most radical prediction of the. 58 00:02:52,080 --> 00:02:54,199 Speaker 1: Century, a mere world of antimatter. 59 00:02:54,360 --> 00:02:57,319 Speaker 2: To really appreciate the scale of Directs achievement, we have 60 00:02:57,400 --> 00:02:59,599 to start with the two scientific giants he was trying 61 00:02:59,639 --> 00:03:03,159 to bridge. Let's begin with Einstein's special relativity from nineteen 62 00:03:03,240 --> 00:03:03,639 oh five. 63 00:03:03,759 --> 00:03:07,159 Speaker 1: Okay, let's unpack that foundation special relativity at its core 64 00:03:07,360 --> 00:03:10,879 is deceptively simple, but its consequences are just earth shattering. 65 00:03:11,080 --> 00:03:15,199 Speaker 2: It rests on two main ideas two posculates. First, the 66 00:03:15,280 --> 00:03:17,479 laws of physics are the same for everyone moving at 67 00:03:17,520 --> 00:03:18,280 a constant speed. 68 00:03:19,039 --> 00:03:21,639 Speaker 1: And second, and this is the really wild one, the 69 00:03:21,680 --> 00:03:24,719 speed of light in a vacuum, about three hundred million 70 00:03:24,840 --> 00:03:28,000 meters per second, is constant. It doesn't matter how fast 71 00:03:28,039 --> 00:03:30,240 you're moving or how fast the light source is moving. 72 00:03:30,520 --> 00:03:33,159 Speaker 2: And that's second point is the crucial one, because if 73 00:03:33,159 --> 00:03:35,479 the speed of light has to be the same for everyone, 74 00:03:36,080 --> 00:03:38,840 then our everyday measurements of space and time can't be 75 00:03:38,879 --> 00:03:39,560 fixed anymore. 76 00:03:39,680 --> 00:03:43,039 Speaker 1: Right, If you're moving really fast, time literally slows down 77 00:03:43,120 --> 00:03:47,120 for you relative to someone who's stationary, and lengths contract exactly. 78 00:03:47,240 --> 00:03:51,240 Speaker 2: It forces space and time to be intrinsically intertwined into 79 00:03:51,280 --> 00:03:54,879 a single, unified, four dimensional framework we call space time. 80 00:03:55,120 --> 00:03:57,960 Speaker 1: And this leads us to the most recognizable equation in 81 00:03:58,039 --> 00:04:01,520 all of science, e MC squared Right. 82 00:04:01,759 --> 00:04:04,159 Speaker 2: Our sources highlight that Einstein found that when an object 83 00:04:04,199 --> 00:04:09,080 loses energy, say by emitting light, its mass must also decrease. 84 00:04:09,240 --> 00:04:11,400 Speaker 1: So mass and energy are just different sides of the 85 00:04:11,400 --> 00:04:14,360 same coin. Different manifestations of the same fundamental thing. 86 00:04:14,560 --> 00:04:18,680 Speaker 2: Absolutely, E equals mc squared defines the energy an object 87 00:04:18,759 --> 00:04:21,720 has simply by having what's called rest mass. It's the 88 00:04:21,759 --> 00:04:23,600 lowest possible energy state. 89 00:04:23,439 --> 00:04:26,040 Speaker 1: The particles are. You know, they're rarely just sitting still, 90 00:04:26,160 --> 00:04:27,759 especially in quantum experiments. 91 00:04:27,839 --> 00:04:32,000 Speaker 2: Exactly, so we need the full relativistic energy equation, which 92 00:04:32,040 --> 00:04:36,519 includes Bartle's momentum pr That full relationship is E squared 93 00:04:36,600 --> 00:04:40,160 equals PC squared plus MC squared squared. 94 00:04:40,319 --> 00:04:43,560 Speaker 1: Wait, I'm curious. If E equals mc squared is the 95 00:04:43,600 --> 00:04:48,079 minimum energy, how does factoring in momentum change that picture? 96 00:04:48,560 --> 00:04:50,920 And why is that so crucial before we even touch 97 00:04:51,000 --> 00:04:51,839 quantum mechanics. 98 00:04:52,040 --> 00:04:54,600 Speaker 2: That's a great question. E equals mc squared is the 99 00:04:54,639 --> 00:04:58,560 rest energy. The pc squared term is basically the kinetic energy, 100 00:04:58,800 --> 00:05:02,160 but expressed relative bastically. Okay, the crucial difference is that 101 00:05:02,319 --> 00:05:05,839 energy squared is proportional to momentum squared. When a particle 102 00:05:05,839 --> 00:05:09,519 steeds up, it's total energy increases beyond its rest mass energy. 103 00:05:09,639 --> 00:05:12,120 Speaker 1: And it's this full equation that has to hold true 104 00:05:12,160 --> 00:05:14,480 for all particles, right, even those as have been close 105 00:05:14,519 --> 00:05:15,240 to the speed of light. 106 00:05:15,399 --> 00:05:18,600 Speaker 2: Yes, and it's this equation that immediately introduces the problem. 107 00:05:18,759 --> 00:05:22,480 Speaker 1: And here's where that mathematical necessity, the tiny sign that 108 00:05:22,560 --> 00:05:25,399 just shattered the foundations of physics, creeps in. 109 00:05:25,600 --> 00:05:29,199 Speaker 2: To get the expression for energy E from that full relationship, 110 00:05:29,519 --> 00:05:31,160 you have to do one simple step. 111 00:05:31,240 --> 00:05:32,199 Speaker 1: Take the square root. 112 00:05:32,360 --> 00:05:35,759 Speaker 2: You take the square root of the right side, and mathematically, 113 00:05:35,759 --> 00:05:38,759 whenever you take a square root, you automatically introduce the 114 00:05:38,759 --> 00:05:39,800 plus or minus sign. 115 00:05:40,279 --> 00:05:40,800 Speaker 1: Ah. 116 00:05:40,920 --> 00:05:44,480 Speaker 2: So this means that for any real configuration of momentum 117 00:05:44,480 --> 00:05:49,160 and mass, there are always two mathematicum valid solutions for 118 00:05:49,199 --> 00:05:53,439 the energy E, a positive value and a negative value. 119 00:05:53,600 --> 00:05:56,399 Speaker 1: Now, in classical physics, nobody cared about this. You know, 120 00:05:56,439 --> 00:05:58,000 if you calculate the length of a side of a 121 00:05:58,040 --> 00:06:00,680 triangle is plus or minus five, you just throw out 122 00:06:00,720 --> 00:06:03,439 the negative five because length can't be negative exactly. 123 00:06:03,600 --> 00:06:07,560 Speaker 2: Classical physicists just ignored the negative solutions in the energy calculation. 124 00:06:07,879 --> 00:06:11,279 They deem them physically meaningless. The convention was we'll just 125 00:06:11,319 --> 00:06:12,560 discard the inconvenience. 126 00:06:12,759 --> 00:06:16,040 Speaker 1: But the sources really stress that those easy classical assumptions 127 00:06:16,040 --> 00:06:19,199 were being overthrown by the bizarre reality of quantum mechanics. 128 00:06:19,519 --> 00:06:22,720 Speaker 2: You couldn't just toss out inconvenient math when you're dealing 129 00:06:22,720 --> 00:06:26,560 with reality at the atomic scale. At that level, mathematical 130 00:06:26,560 --> 00:06:29,800 elegance and symmetry often proved to be more important than 131 00:06:29,839 --> 00:06:31,319 your initial physical intuition. 132 00:06:31,839 --> 00:06:34,720 Speaker 1: That sets the perfect stage for the collision. We have 133 00:06:34,759 --> 00:06:37,759 special relativity on one side, and now let's pivot to 134 00:06:37,839 --> 00:06:40,839 the other giant. The quantum revolution. 135 00:06:41,720 --> 00:06:44,439 Speaker 2: The quantum revolution, which really kicked off in the first 136 00:06:44,439 --> 00:06:47,720 few decades of the twentieth century, revealed that the subatomic 137 00:06:47,759 --> 00:06:49,560 world is just inherently strange. 138 00:06:49,800 --> 00:06:53,160 Speaker 1: Like how energy levels for particles are discrete or quantized, 139 00:06:53,240 --> 00:06:56,319 they jump between levels, they don't flow continuously. 140 00:06:55,879 --> 00:07:00,480 Speaker 2: Exactly, and most mind bendingly, particles like electrons don't behave 141 00:07:00,560 --> 00:07:04,240 like little billiard balls. They also exhibit wave behavior. This 142 00:07:04,319 --> 00:07:06,120 is the famous particle wave duality. 143 00:07:06,240 --> 00:07:09,279 Speaker 1: Right. If you shoot electrons through two tiny slits, they 144 00:07:09,319 --> 00:07:11,680 create an interference pattern like ripples and water. 145 00:07:11,800 --> 00:07:14,199 Speaker 2: Yes, they spread out an overlap, just like waves do. 146 00:07:14,519 --> 00:07:17,279 And this forced a complete overhaul of how we model 147 00:07:17,319 --> 00:07:18,319 the subatomic world. 148 00:07:18,480 --> 00:07:21,319 Speaker 1: And this brings us to Erwin Schrodinger, who in nineteen 149 00:07:21,360 --> 00:07:24,839 twenty six developed the framework to handle this duality, his 150 00:07:24,959 --> 00:07:26,399 famous wave equation. 151 00:07:26,920 --> 00:07:30,480 Speaker 2: Schrodinger's equation is the fundamental law that describes how quantum 152 00:07:30,480 --> 00:07:34,120 systems evolve over time. Its solution is the wave function, 153 00:07:34,399 --> 00:07:36,519 which we usually call sigh and. 154 00:07:36,560 --> 00:07:39,879 Speaker 1: SI itself doesn't give you the particle's definite location. 155 00:07:39,759 --> 00:07:42,639 Speaker 2: No it doesn't. Instead, the modulus square to the wave 156 00:07:42,639 --> 00:07:46,079 function gives you the probability of finding that particle in 157 00:07:46,120 --> 00:07:48,439 a specific location at a specific time. 158 00:07:48,560 --> 00:07:50,920 Speaker 1: And the derivation is so elegant because it starts with 159 00:07:50,959 --> 00:07:55,240 the classical framework, the classical kinetic energy expression E equals 160 00:07:55,319 --> 00:07:56,879 p squared over two meter. 161 00:07:57,319 --> 00:08:01,480 Speaker 2: That's the starting point. To make it quantum, Schrodinger replaced 162 00:08:01,519 --> 00:08:04,720 the classical variables for energy and momentum with what are 163 00:08:04,720 --> 00:08:06,120 called quantum operators. 164 00:08:06,199 --> 00:08:08,519 Speaker 1: These are just mathematical tools that let you pull out 165 00:08:08,600 --> 00:08:11,399 properties like energy or momentum from the wave function. 166 00:08:11,600 --> 00:08:15,319 Speaker 2: And this approach worked brilliantly for describing, say, slow moving 167 00:08:15,360 --> 00:08:16,920 electrons in simple atoms. 168 00:08:17,399 --> 00:08:20,360 Speaker 1: But as you said, there's a limit. Because Schrodinger started 169 00:08:20,399 --> 00:08:24,639 with the classical kinetic energy formula, his equation completely fails 170 00:08:24,639 --> 00:08:26,600 for particles moving near the speed of light. 171 00:08:26,759 --> 00:08:29,759 Speaker 2: It does, and the consequences of this failure are actually 172 00:08:29,800 --> 00:08:31,480 visible in our macroscopic world. 173 00:08:31,759 --> 00:08:35,720 Speaker 1: In chemistry, right, the source material offers two fantastic examples 174 00:08:36,000 --> 00:08:38,639 the color of gold and the liquidity of mercury. 175 00:08:38,919 --> 00:08:43,799 Speaker 2: Yes, Schrodinger's non relativistic equation predicts that gold should be 176 00:08:43,840 --> 00:08:47,639 a silvery gray color like platinum or silver, but of 177 00:08:47,679 --> 00:08:48,720 course gold is yellow. 178 00:08:48,960 --> 00:08:52,360 Speaker 1: It also predicts that mercury, with its heavy atoms, should 179 00:08:52,440 --> 00:08:56,279 be a solid at room temperature, but it's famously a liquid. 180 00:08:56,600 --> 00:08:58,440 Speaker 2: And the hint, like you said, is that both gold 181 00:08:58,480 --> 00:09:00,000 and mercury are heavy elements. 182 00:09:00,360 --> 00:09:03,200 Speaker 1: So why does being heavy matter so much that it 183 00:09:03,240 --> 00:09:04,960 requires relativistic physics? 184 00:09:05,240 --> 00:09:08,960 Speaker 2: Because they have a huge number of protons in their nucleus. 185 00:09:09,720 --> 00:09:14,639 This large positive charge attracts the orbiting electrons very very strongly. 186 00:09:14,480 --> 00:09:17,639 Speaker 1: So the innermost electrons are moving incredibly. 187 00:09:17,000 --> 00:09:20,600 Speaker 2: Fast, unbelievably fast. They're whizzing around at speeds approaching half 188 00:09:20,639 --> 00:09:21,279 the speed of light. 189 00:09:21,399 --> 00:09:24,799 Speaker 1: Okay, and once they hit those relativistic speeds, the classical 190 00:09:24,879 --> 00:09:28,240 kinetic energy formula that Schrodinger used is just plain wrong. 191 00:09:28,360 --> 00:09:31,159 Speaker 2: The entire structure of his equation is not consistent with 192 00:09:31,200 --> 00:09:33,679 special relativity. It's only an approximation. 193 00:09:34,080 --> 00:09:37,000 Speaker 1: So the fix seemed obvious to the physicists of the time. 194 00:09:37,480 --> 00:09:40,360 Just you know, toss out the classical energy formula and 195 00:09:40,399 --> 00:09:44,720 replace it with the correct relativistic one from Einstein. 196 00:09:44,279 --> 00:09:48,600 Speaker 2: Precisely, and that's what several physicists Oscar Klein, Walter Gordon, 197 00:09:48,840 --> 00:09:52,200 and Vladimir Fowk did independently around nineteen twenty six. 198 00:09:52,279 --> 00:09:55,159 Speaker 1: They derived a new wave equation by applying those quantum 199 00:09:55,200 --> 00:09:58,559 operators to the squared relativistic energy relation. 200 00:09:58,440 --> 00:10:00,480 Speaker 2: And the result was the Klein Gordon equation. 201 00:10:00,799 --> 00:10:04,279 Speaker 1: This looked like the solution. It incorporated relativity, it was 202 00:10:04,320 --> 00:10:06,879 still a quantum wave equation, but our sources make it 203 00:10:06,919 --> 00:10:10,919 clear that young Paul Durack, who was just quietly observing 204 00:10:10,960 --> 00:10:13,639 all this, knew it was fatally flawed. 205 00:10:13,720 --> 00:10:16,559 Speaker 2: They had simply traded one set of problems for another, 206 00:10:16,919 --> 00:10:19,600 and this new set was even more catastrophic. 207 00:10:19,759 --> 00:10:22,720 Speaker 1: There were two immediate fatal flaws, right. The first one 208 00:10:22,759 --> 00:10:25,240 came from the mathematical structure, from how they handled the 209 00:10:25,360 --> 00:10:26,600 energy square exactly. 210 00:10:26,639 --> 00:10:29,240 Speaker 2: They started with E squared, which is inherently a second 211 00:10:29,320 --> 00:10:32,159 order term, So when you turn that into a quantum operator, 212 00:10:32,320 --> 00:10:35,360 the resulting Klein Gordon equation had to include a term 213 00:10:35,399 --> 00:10:37,759 that was a second order time derivative. 214 00:10:37,600 --> 00:10:40,879 Speaker 1: Meaning the wave function had to be differentiated twice with 215 00:10:40,960 --> 00:10:44,200 respect to time. Yes, okay, let's drill down into that. 216 00:10:44,639 --> 00:10:47,759 Why is a second order time derivative so bad? The 217 00:10:47,799 --> 00:10:50,200 sources give a great analogy, right. 218 00:10:50,639 --> 00:10:53,519 Speaker 2: Think about predicting the future motion of a baseball. If 219 00:10:53,600 --> 00:10:55,679 you want to know exactly where that ball will be 220 00:10:55,720 --> 00:10:59,720 at any future time, you need two pieces of initial information. 221 00:10:59,480 --> 00:11:02,639 Speaker 1: Its position and its velocity, where it started and how 222 00:11:02,679 --> 00:11:03,159 fast you. 223 00:11:03,120 --> 00:11:06,679 Speaker 2: Through it exactly the initial position and the first time 224 00:11:06,759 --> 00:11:10,120 derivative of its position. Got it? Now? Compare that to 225 00:11:10,159 --> 00:11:14,440 the elegance of Schrodinger's original equation. The whole point was 226 00:11:14,480 --> 00:11:18,519 that the wave function SIGH alone contained all the necessary 227 00:11:18,519 --> 00:11:20,399 information to predict the future. 228 00:11:20,360 --> 00:11:22,320 Speaker 1: Because it was only first order in time. You just 229 00:11:22,360 --> 00:11:24,559 needed the wave function at time zero precisely. 230 00:11:24,840 --> 00:11:27,320 Speaker 2: But the Klin Goordon equation, because it was second order 231 00:11:27,360 --> 00:11:29,759 in time, meant that the wave function alone could no 232 00:11:29,840 --> 00:11:33,159 longer predict the future. You'd need the wave function and 233 00:11:33,240 --> 00:11:34,679 its initial time derivative. 234 00:11:34,759 --> 00:11:37,679 Speaker 1: So it shattered the simplicity and predictive power that quantum 235 00:11:37,720 --> 00:11:38,960 mechanics had established. 236 00:11:39,200 --> 00:11:42,440 Speaker 2: But the second objection was even more devastating. It led 237 00:11:42,440 --> 00:11:45,519 to what Direct famously called physically nonsense. 238 00:11:45,919 --> 00:11:49,679 Speaker 1: This was the issue of negative probabilities. Yes, a probability 239 00:11:49,840 --> 00:11:52,200 just cannot be less than zero. The chance of finding 240 00:11:52,240 --> 00:11:54,480 a particle has to be between zero percent and one 241 00:11:54,559 --> 00:11:55,919 hundred percent exactly. 242 00:11:56,279 --> 00:11:59,519 Speaker 2: Our sources explained that the mathematical machinery required to calculate 243 00:11:59,519 --> 00:12:03,919 probability using the Klein Gordon wave function could, under certain 244 00:12:03,960 --> 00:12:07,200 conditions spit out a negative value. 245 00:12:06,639 --> 00:12:08,919 Speaker 1: And a theory that predicts a negative chance of finding 246 00:12:08,919 --> 00:12:11,639 a particle is just well, it's physically bankrupt. 247 00:12:11,879 --> 00:12:15,399 Speaker 2: This confirmed that the Klein Gordon equation was fundamentally inadequate 248 00:12:15,440 --> 00:12:18,200 for describing single particles like the electron. 249 00:12:18,399 --> 00:12:22,039 Speaker 1: So the challenge was clear. Physics needed a relativistic equation 250 00:12:22,120 --> 00:12:24,759 that was first order in the time derivative to get 251 00:12:24,840 --> 00:12:27,440 rid of that negative probability issue. 252 00:12:27,039 --> 00:12:28,919 Speaker 2: And the stage was now perfectly set for. 253 00:12:28,879 --> 00:12:31,840 Speaker 1: Direct This brings us to Paul Direc himself, a man 254 00:12:32,000 --> 00:12:35,919 often called the strangest man, and his personality is really 255 00:12:36,000 --> 00:12:37,879 essential to understanding this breakthrough. 256 00:12:38,200 --> 00:12:41,279 Speaker 2: His motivation wasn't just to fix the problems, but to 257 00:12:41,279 --> 00:12:43,559 find a deeper, more beautiful truth. 258 00:12:43,960 --> 00:12:47,320 Speaker 1: The anecdotes about him are wonderful. He was once invited 259 00:12:47,320 --> 00:12:49,759 to dinner and sat for three hours without saying a 260 00:12:49,799 --> 00:12:51,360 single word, because. 261 00:12:51,039 --> 00:12:53,679 Speaker 2: As he put it, he just saw no reason to speak. 262 00:12:54,279 --> 00:12:57,360 His colleagues even invented a unit of conversation, the direct 263 00:12:57,759 --> 00:12:59,600 defined as one word per hour. 264 00:13:00,200 --> 00:13:01,919 Speaker 1: Climbing trees in three piece suits. 265 00:13:02,120 --> 00:13:05,759 Speaker 2: That combination of rigor and almost childlike detachment meant his 266 00:13:05,840 --> 00:13:09,639 focus was singular. What truly defined him was his absolute 267 00:13:09,759 --> 00:13:11,720 dedication to mathematical elegance. 268 00:13:11,960 --> 00:13:14,799 Speaker 1: He famously said, it is more important to have beauty 269 00:13:14,799 --> 00:13:17,360 in one's equations than to have them fit experiment. 270 00:13:17,879 --> 00:13:21,279 Speaker 2: That is just a staggering position to take to prioritize 271 00:13:21,279 --> 00:13:24,159 the form of the math over the initial data, and. 272 00:13:24,080 --> 00:13:27,279 Speaker 1: That passion for pure deductive reasoning was the engine for 273 00:13:27,360 --> 00:13:27,840 his search. 274 00:13:28,039 --> 00:13:31,200 Speaker 2: So his core task was what we call linearization. He 275 00:13:31,279 --> 00:13:34,919 needed to take that squared relativistic energy relationship and rewrite 276 00:13:34,960 --> 00:13:37,799 it as a linear equation so only first order terms. 277 00:13:38,000 --> 00:13:40,360 Speaker 1: That way, the result in quantum equation would also be 278 00:13:40,399 --> 00:13:42,759 first order in the time derivative, which would solve the 279 00:13:42,799 --> 00:13:44,399 negative probability problem. 280 00:13:44,519 --> 00:13:47,720 Speaker 2: To do this, he essentially just wrote down a linear 281 00:13:47,840 --> 00:13:50,759 form of the energy equation, but to make it work, 282 00:13:51,159 --> 00:13:53,879 he had to introduce a set of four unknown coefficients 283 00:13:54,519 --> 00:13:59,080 he labeled them alpha x, alpha y, alpha z, and beta. 284 00:13:59,120 --> 00:14:01,480 Speaker 1: These were the magic ingredients that had to make sure 285 00:14:01,519 --> 00:14:04,679 his linear equation. When you squared, it gave you back 286 00:14:04,720 --> 00:14:07,559 the exact original relativistic expression. 287 00:14:07,720 --> 00:14:10,519 Speaker 2: And when he did that, when he squared his proposed 288 00:14:10,559 --> 00:14:13,600 linear equation to solve for the properties of these coefficients, 289 00:14:14,039 --> 00:14:17,080 he immediately hit a profound mathematical wall. 290 00:14:17,080 --> 00:14:18,440 Speaker 1: The non commutative barrier. 291 00:14:18,559 --> 00:14:22,120 Speaker 2: The non commutative barrier the math demanded two things. First, 292 00:14:22,279 --> 00:14:25,919 when you square each individual coefficient, the result must be one. 293 00:14:26,200 --> 00:14:28,159 That's easy, they could just be one or a metas one. 294 00:14:28,480 --> 00:14:30,279 Speaker 1: But the second requirement was the tough part. 295 00:14:30,559 --> 00:14:33,960 Speaker 2: Yes, it required that certain combinations of coefficients when a 296 00:14:34,039 --> 00:14:38,200 multiplied must vanish. For example, alpha x times beta plus 297 00:14:38,200 --> 00:14:40,200 beta times alpha x had to equal zero. 298 00:14:40,360 --> 00:14:43,240 Speaker 1: And if these were regular everyday numbers, this just doesn't work. 299 00:14:43,360 --> 00:14:46,120 Speaker 2: It fails completely. If alpha x is one and beta 300 00:14:46,120 --> 00:14:48,399 is misus one, then you get one times minus one 301 00:14:48,440 --> 00:14:49,240 plus minus one. 302 00:14:49,159 --> 00:14:51,320 Speaker 1: Times one, which is minus one plus minus one. That's 303 00:14:51,360 --> 00:14:53,679 minus two, not zero exactly. 304 00:14:53,919 --> 00:14:57,000 Speaker 2: For regular numbers, the order of multiplication doesn't matter. A 305 00:14:57,200 --> 00:14:59,000 times D is always B times A. 306 00:14:59,279 --> 00:15:01,080 Speaker 1: So the only way of that to work is if 307 00:15:01,159 --> 00:15:03,840 A times b is the negative of B times a, 308 00:15:04,200 --> 00:15:07,559 which meant the order of multiplication had to matter. He 309 00:15:07,600 --> 00:15:11,000 couldn't use standard numbers, and this required leveraging an idea 310 00:15:11,039 --> 00:15:14,840 that had already revolutionized quantum physics thanks to his friend 311 00:15:15,000 --> 00:15:17,360 Werner Heisenberg's. 312 00:15:16,360 --> 00:15:20,200 Speaker 2: So Wonderful Irony, Isn't It? The Quiet detached direct Relying 313 00:15:20,320 --> 00:15:22,360 on the work of the flamboyant. 314 00:15:21,759 --> 00:15:24,960 Speaker 1: Heisenberg, Heisenberg had found that in the quantum world, for 315 00:15:25,080 --> 00:15:28,759 certain pairs of properties like position and momentum, the order 316 00:15:28,799 --> 00:15:31,039 in which you measure them changes the outcome. 317 00:15:31,279 --> 00:15:33,200 Speaker 2: Right, x times p is not the same as p 318 00:15:33,360 --> 00:15:36,240 times x. That's the uncertainty principle. 319 00:15:36,000 --> 00:15:40,519 Speaker 1: And Heisenberg's mentor Max Bourne, suggested that this strange noncommutative 320 00:15:40,559 --> 00:15:44,279 property could be represented using mathematical structures called matrices. 321 00:15:44,440 --> 00:15:47,480 Speaker 2: Matrices they're just a rays of numbers used to represent 322 00:15:47,519 --> 00:15:52,480 transformations like rotation or reflection, and they naturally obey noncommutated. 323 00:15:51,799 --> 00:15:55,200 Speaker 1: Multiplication, like if you rotate an object and then reflect it, 324 00:15:55,480 --> 00:15:57,320 you get a different result than if you reflect it 325 00:15:57,360 --> 00:15:59,320 first and then rotate it. Order matters. 326 00:15:59,480 --> 00:16:03,440 Speaker 2: This was the realization Durac knew his coefficients had to 327 00:16:03,519 --> 00:16:04,759 be matrices. 328 00:16:04,639 --> 00:16:08,000 Speaker 1: He first tried two by two matrices, the smallest option. 329 00:16:07,879 --> 00:16:10,960 Speaker 2: But no combination of two by two matrices could satisfy 330 00:16:11,120 --> 00:16:15,600 all the complex simultaneous equations that his math required, so 331 00:16:15,639 --> 00:16:16,440 he was stuck. 332 00:16:16,679 --> 00:16:19,399 Speaker 1: The math required something that couldn't be satisfied by the 333 00:16:19,440 --> 00:16:20,600 simplest option. 334 00:16:20,480 --> 00:16:23,279 Speaker 2: And the breakthrough, as the sources describe it, was just 335 00:16:23,320 --> 00:16:27,360 a sudden, bold jump. Durak realized there was no rule 336 00:16:27,480 --> 00:16:29,440 saying how big the matrices had to be. 337 00:16:29,399 --> 00:16:32,159 Speaker 1: So he just jumped up to four by four matrices. 338 00:16:32,200 --> 00:16:34,399 Speaker 2: He jumped to four by four matrices for his coefficients. 339 00:16:34,519 --> 00:16:37,159 Speaker 1: That's astonishing. It wasn't a guess based on data. It 340 00:16:37,200 --> 00:16:39,559 was a purely mathematical requirement. 341 00:16:39,120 --> 00:16:42,200 Speaker 2: Precisely, and that bold move to four by four matrices 342 00:16:42,440 --> 00:16:44,679 satisfied every single mathematical constraint. 343 00:16:44,879 --> 00:16:48,279 Speaker 1: So he substituted those back into his linear equation, applied 344 00:16:48,320 --> 00:16:51,559 the quantum operators, and arrived at his relativistic equation for 345 00:16:51,600 --> 00:16:52,480 the free electron. 346 00:16:52,679 --> 00:16:55,879 Speaker 2: And according to his contemporaries, the final equation itself was 347 00:16:55,919 --> 00:17:00,000 just breathtaking. People expected a messy, convoluted solution. 348 00:16:59,840 --> 00:17:03,480 Speaker 1: But what emerged was a structure of profound symmetry and elegance. 349 00:17:03,879 --> 00:17:08,880 Speaker 2: Let's talk about the immediate unexpected triumphs of this mathematical beauty. First, 350 00:17:09,240 --> 00:17:10,960 the symmetry of the equation itself. 351 00:17:11,000 --> 00:17:13,640 Speaker 1: It was relativistic, It was first order in time, and. 352 00:17:13,599 --> 00:17:16,599 Speaker 2: Crucially, because of the matrix constraints, it was also first 353 00:17:16,720 --> 00:17:19,079 order in all the spatial derivatives. 354 00:17:18,559 --> 00:17:21,759 Speaker 1: So it treats time and space with perfect symmetry, no 355 00:17:21,920 --> 00:17:25,720 squared terms. This is essential for a theory rooted in 356 00:17:25,799 --> 00:17:27,440 Einstein's space time. 357 00:17:27,440 --> 00:17:30,160 Speaker 2: And this commitment to matrix math forced an unlooked for 358 00:17:30,279 --> 00:17:34,240 consequence on physics. The four x four matrices required that 359 00:17:34,279 --> 00:17:38,799 the solution the wave function SI had to have four components. 360 00:17:38,319 --> 00:17:42,160 Speaker 1: Four components describing four possible fundamental states for the electron, 361 00:17:42,480 --> 00:17:47,480 and here is the first massive, unlooked for triumph. Electron spin. 362 00:17:47,839 --> 00:17:50,319 Speaker 2: The top two components of that four part wave function 363 00:17:50,680 --> 00:17:55,440 naturally described the electron's two possible states of intrinsic angular momentum, 364 00:17:55,960 --> 00:17:57,359 spin up and spin down. 365 00:17:57,480 --> 00:18:00,960 Speaker 1: This was revolutionary. Before direct physicist had been forced to 366 00:18:01,000 --> 00:18:04,039 just add spin to the Schrodinger equation by hand. It 367 00:18:04,079 --> 00:18:06,480 was something they saw in experiments but couldn't explain. 368 00:18:06,799 --> 00:18:12,279 Speaker 2: But here spin emerged organically naturally from Direct's relentless quest 369 00:18:12,359 --> 00:18:16,960 for mathematical elegance. He designed the equation to be relativistic, 370 00:18:17,559 --> 00:18:19,359 and spin just fell out of the math. 371 00:18:19,640 --> 00:18:22,920 Speaker 1: It's amazing the sheer size of the array determine the reality. 372 00:18:23,319 --> 00:18:26,519 And this also explained another key mystery in atomic physics, 373 00:18:26,880 --> 00:18:27,799 fine structure. 374 00:18:28,039 --> 00:18:32,200 Speaker 2: Yes, the spin creates a tiny internal magnetic field for 375 00:18:32,240 --> 00:18:36,920 the electron. When an electron orbits the nucleus from its perspective, 376 00:18:37,400 --> 00:18:40,039 the positively charged proton is orbiting it. 377 00:18:40,319 --> 00:18:43,640 Speaker 1: And that orbiting proton creates a separate, larger magnetic field. 378 00:18:43,799 --> 00:18:47,279 Speaker 2: Exactly so, you have two magnets interacting, the electrons tiny 379 00:18:47,279 --> 00:18:50,119 internal magnet and the magnetic field from the proton's apparent motion. 380 00:18:50,400 --> 00:18:53,200 Speaker 1: And this interaction causes a slight energy difference between the 381 00:18:53,200 --> 00:18:55,200 spin up state and the spin down state. 382 00:18:55,119 --> 00:18:57,720 Speaker 2: Which causes the single energy level to split into two 383 00:18:58,160 --> 00:19:01,880 very closely spaced levels. This splitting is the fine structure 384 00:19:01,880 --> 00:19:04,279 you can see in the emission spectrum of hydrogen. 385 00:19:04,599 --> 00:19:08,000 Speaker 1: Schrodinger's one component wave function could never account for the splitting, 386 00:19:08,359 --> 00:19:12,079 but Direct's four component solution, with its two distinct spin states, 387 00:19:12,200 --> 00:19:13,480 accounted for it perfectly. 388 00:19:13,759 --> 00:19:18,119 Speaker 2: This was a massive confirmation the underlying mathematical structure the 389 00:19:18,200 --> 00:19:20,440 four x four matrixs was correct. 390 00:19:20,680 --> 00:19:23,640 Speaker 1: But as we said at the start, this beauty concealed 391 00:19:23,640 --> 00:19:27,440 the original crisis. This success brings us right back to 392 00:19:27,440 --> 00:19:30,200 that disastrous nineteen twenty eight lecture. 393 00:19:30,039 --> 00:19:33,480 Speaker 2: The Saddus Chapter of Physics, because while the equation with 394 00:19:33,599 --> 00:19:37,400 beautiful and predicted spin, it still carried that unavoidable mathematical 395 00:19:37,480 --> 00:19:39,119 baggage required by the square root. 396 00:19:39,319 --> 00:19:42,000 Speaker 1: Right when you simplify the direct equation for a particle 397 00:19:42,039 --> 00:19:44,079 at rest, you're left with a clear result. 398 00:19:44,480 --> 00:19:48,079 Speaker 2: The particle's energy must be proportional to mc squared. But 399 00:19:48,160 --> 00:19:51,880 because of the matrix structure, that result yields two positive 400 00:19:52,000 --> 00:19:54,880 energy solutions, the spin up and spin down states, and 401 00:19:54,920 --> 00:19:56,559 two negative energy solutions. 402 00:19:56,640 --> 00:19:59,519 Speaker 1: So the negative energy solutions were still there, baked into 403 00:19:59,519 --> 00:20:02,759 the equation as a fundamental requirement, and why couldn't they 404 00:20:02,799 --> 00:20:05,119 just throw them out like the classical physicists did. 405 00:20:05,200 --> 00:20:08,799 Speaker 2: Because in quantum theory, an electron isn't strictly localized. It 406 00:20:08,839 --> 00:20:11,759 has a non zero probability of making a transition from 407 00:20:11,799 --> 00:20:13,319 one energy state to another. 408 00:20:13,279 --> 00:20:18,000 Speaker 1: So the implication is terrifying. If negative energy states truly existed, 409 00:20:18,400 --> 00:20:22,079 the positive energy electron would inevitably make a quantum jump 410 00:20:22,119 --> 00:20:23,880 down into one of those negative states. 411 00:20:23,960 --> 00:20:26,880 Speaker 2: It's the physical nightmare. If an electron could drop into 412 00:20:26,920 --> 00:20:29,240 a negative energy state, it would have to radiate its 413 00:20:29,319 --> 00:20:31,960 positive energy as a photon. 414 00:20:32,160 --> 00:20:35,160 Speaker 1: But there's no bottom to the negative energy abyss. It 415 00:20:35,160 --> 00:20:37,440 could just keep falling forever endlessly. 416 00:20:37,960 --> 00:20:40,880 Speaker 2: It would drop into an even lower negative state, emitting 417 00:20:40,880 --> 00:20:45,599 more photons. The universe would be fundamentally unstable. All positive 418 00:20:45,599 --> 00:20:48,400 matter would instantly collapse into a radiation burst. 419 00:20:48,759 --> 00:20:51,599 Speaker 1: This is why HISS contemporaries were losing their minds. The 420 00:20:51,640 --> 00:20:54,119 equation was too good to be wrong, yet it predicted 421 00:20:54,160 --> 00:20:55,400 the collapse of the universe. 422 00:20:55,599 --> 00:20:59,519 Speaker 2: Direct facing this ridiculous physical scenario had to rescue his 423 00:20:59,559 --> 00:21:00,640 own theory, and in. 424 00:21:00,640 --> 00:21:03,839 Speaker 1: Nineteen thirty one, three years after the initial chaos, he 425 00:21:03,960 --> 00:21:07,960 proposed the most radical theoretical fix imaginable to explain those 426 00:21:07,960 --> 00:21:09,920 two remaining negative energy states. 427 00:21:10,000 --> 00:21:13,640 Speaker 2: He proposed a new particle, an anti electron. He would 428 00:21:13,640 --> 00:21:16,480 have the same mass as the electron, but the opposite charge. 429 00:21:16,240 --> 00:21:19,279 Speaker 1: Positive, So the four components of his wavefunction were finally 430 00:21:19,359 --> 00:21:22,759 physically justified. Spin up electrons, spin down electrons, spin up 431 00:21:22,759 --> 00:21:26,079 anti electron, and spin down anti electron. 432 00:21:25,759 --> 00:21:29,039 Speaker 2: But this was still just pure theory, a desperate bid 433 00:21:29,079 --> 00:21:30,279 to save his equation. 434 00:21:30,559 --> 00:21:33,519 Speaker 1: And Durac didn't initially believe this particle would be easily 435 00:21:33,599 --> 00:21:35,200 found right, No, because. 436 00:21:34,960 --> 00:21:38,000 Speaker 2: If the electron was negative and this new particle was positive, 437 00:21:38,519 --> 00:21:41,079 they would annihilate each other instantly. He thought we wouldn't 438 00:21:41,079 --> 00:21:42,960 find many of them in our matter dominated world. 439 00:21:43,480 --> 00:21:46,200 Speaker 1: But just one year later, in nineteen thirty two, a 440 00:21:46,279 --> 00:21:50,799 Caltech postdoc named Carl Anderson provided the experimental proof. 441 00:21:51,160 --> 00:21:54,839 Speaker 2: Anderson was studying particles produced by cosmic rays using a 442 00:21:54,839 --> 00:21:57,119 cloud chamber inside a powerful magnet. 443 00:21:57,240 --> 00:22:00,000 Speaker 1: A cloud chamber is a marvelous device. It's a container 444 00:22:00,279 --> 00:22:03,519 with supersaturated vapor, and when a charged particle zips through, 445 00:22:03,599 --> 00:22:05,079 it leaves a condensation trail. 446 00:22:05,359 --> 00:22:08,359 Speaker 2: And in a magnetic field, negative electrons curve one way, 447 00:22:08,640 --> 00:22:12,359 and positive protons, which are much heavier, curved the opposite way, 448 00:22:12,519 --> 00:22:14,200 but with a much shallower curve. 449 00:22:14,480 --> 00:22:16,920 Speaker 1: Anderson noticed a track that was definitely not a proton. 450 00:22:17,039 --> 00:22:19,519 It was light like an electron, but it curved sharply 451 00:22:19,559 --> 00:22:20,680 in the opposite. 452 00:22:20,200 --> 00:22:22,920 Speaker 2: Direction, indicating it had a positive charge. 453 00:22:23,000 --> 00:22:26,839 Speaker 1: It was the positive electron, which Anderson named the positron. 454 00:22:26,960 --> 00:22:31,000 Speaker 2: Direct's anti electron was real. It was discovered entirely by accident, 455 00:22:31,319 --> 00:22:34,160 less than a year after he proposed its existence based 456 00:22:34,200 --> 00:22:36,720 purely on the necessity of elegant mathematics. 457 00:22:36,880 --> 00:22:39,839 Speaker 1: That is just one of the most stunning predictive successes 458 00:22:39,880 --> 00:22:41,400 in the history of modern physics. 459 00:22:41,440 --> 00:22:44,720 Speaker 2: But the discovery of the positron alone didn't solve the 460 00:22:44,759 --> 00:22:48,680 original problem of the negative energy Abyss. Directs still had 461 00:22:48,680 --> 00:22:50,160 to ground his rescue theory. 462 00:22:50,079 --> 00:22:52,599 Speaker 1: And this leads to the solution that initially sounded like 463 00:22:52,640 --> 00:22:55,680 the ravings of a madman, the direct sea. 464 00:22:55,359 --> 00:22:59,440 Speaker 2: Right to prevent electrons from collapsing. Direct theorized that the 465 00:22:59,559 --> 00:23:03,000 vacuum what we think of is empty space is actually 466 00:23:03,039 --> 00:23:06,799 an infinite sea of electrons occupying all negative energy states. 467 00:23:07,039 --> 00:23:10,119 Speaker 1: And he used the poly exclusion principle, which says no 468 00:23:10,240 --> 00:23:13,519 two electrons can occupy the exact same quantum state. 469 00:23:13,839 --> 00:23:16,359 Speaker 2: So if the entire negative energy realm is already filled 470 00:23:16,400 --> 00:23:19,880 with infinite electrons, there are no vacant states left for 471 00:23:19,920 --> 00:23:22,079 a positive energy electron to jump down into. 472 00:23:22,640 --> 00:23:25,359 Speaker 1: The sea is full, So how does the positron, the 473 00:23:25,400 --> 00:23:28,559 particle Andersen saw, fit into this infinite sea. 474 00:23:28,680 --> 00:23:32,440 Speaker 2: A positron in this model is simply a hole or 475 00:23:32,480 --> 00:23:34,319 a vacancy in the direct sea. 476 00:23:34,400 --> 00:23:37,599 Speaker 1: So if a high energy photon knocks an electron out 477 00:23:37,640 --> 00:23:39,880 of the sea into the positive energy. 478 00:23:39,559 --> 00:23:42,720 Speaker 2: Realm, we observe it as a normal electron, and the 479 00:23:42,839 --> 00:23:46,319 vacant space left behind the hole behaves exactly like a 480 00:23:46,359 --> 00:23:49,640 positive charge particle with the same mass. That's the positron. 481 00:23:49,759 --> 00:23:52,519 Speaker 1: And when an electron and a positron meet and annihilate, 482 00:23:52,640 --> 00:23:55,039 that's just the electron falling back down to fill the 483 00:23:55,039 --> 00:23:55,759 hole in the sea. 484 00:23:55,920 --> 00:23:59,960 Speaker 2: It's a wildly abstract idea, an infinite see underlying all 485 00:24:00,200 --> 00:24:02,960 of reality, and while it worked, a lot of physicists 486 00:24:03,000 --> 00:24:04,920 found it well a bit clunky. 487 00:24:05,200 --> 00:24:08,880 Speaker 1: Thankfully, a far more elegant reinterpretation emerged that did the 488 00:24:08,880 --> 00:24:13,960 mathematical cleanup without needing a physical infinite unobservable c This. 489 00:24:13,839 --> 00:24:16,720 Speaker 2: Is the mind betting concept that a negative energy particle 490 00:24:16,759 --> 00:24:21,319 is mathematically equivalent to a positive energy antiparticle traveling backwards 491 00:24:21,359 --> 00:24:21,720 in time. 492 00:24:21,960 --> 00:24:23,400 Speaker 1: My brain hurts just thinking about that. 493 00:24:23,680 --> 00:24:27,279 Speaker 2: The Swiss physicist Ernst Stuckelberg noted in nineteen forty one 494 00:24:27,400 --> 00:24:30,000 that in the wave function, energy is multiplied by time, 495 00:24:30,200 --> 00:24:32,240 So if you have negative energy, changing the sign of 496 00:24:32,240 --> 00:24:35,720 time gives you a positive result. Mathematically, flipping the direction 497 00:24:35,799 --> 00:24:38,079 of time flips the sign of the energy. 498 00:24:37,880 --> 00:24:41,000 Speaker 1: So a negative energy electron traveling backwards in time is 499 00:24:41,079 --> 00:24:45,279 mathematically identical to a positive energy positron traveling forwards in 500 00:24:45,359 --> 00:24:46,440 time exactly. 501 00:24:46,960 --> 00:24:50,319 Speaker 2: Richard Feinman cemented this idea into modern physics around nineteen 502 00:24:50,400 --> 00:24:54,559 forty eight with his famous Feinmann diagrams. He literally drew 503 00:24:54,640 --> 00:24:57,559 anti particles as arrows moving backwards in time. 504 00:24:57,720 --> 00:25:00,880 Speaker 1: So this was the ultimate resolution. The negative energy solutions 505 00:25:00,960 --> 00:25:04,359 no longer meant the universe was unstable or required an infinite. 506 00:25:04,079 --> 00:25:07,680 Speaker 2: See they simply guarantee the existence of a corresponding antiparticle 507 00:25:07,880 --> 00:25:12,039 for every matter particle, same mass, opposite charge, The proton 508 00:25:12,079 --> 00:25:15,039 has the antiproton, the neutrino has the anti neutrino, and 509 00:25:15,079 --> 00:25:15,400 so on. 510 00:25:15,559 --> 00:25:19,440 Speaker 1: And this prediction a whole mirror universe of antiparticles was 511 00:25:19,480 --> 00:25:22,880 derived purely from the requirement of a mathematically beautiful equation. 512 00:25:23,160 --> 00:25:26,119 Speaker 2: Heisenberg in retrospect called it the biggest leap in twentieth 513 00:25:26,160 --> 00:25:30,119 century physics, all from a refusal to ignore a negative sign. 514 00:25:30,440 --> 00:25:34,200 Speaker 1: And if we connect this world of matter and antimatter 515 00:25:34,319 --> 00:25:38,400 to the biggest picture possible, the cosmos. We find these 516 00:25:38,440 --> 00:25:41,240 processes shape our entire universe. 517 00:25:41,039 --> 00:25:45,319 Speaker 2: Most notably annihilation and creation. Annihilation is when a particle 518 00:25:45,400 --> 00:25:48,680 and its antiparticle meet, they convert all their mass into 519 00:25:48,680 --> 00:25:49,519 pure energy. 520 00:25:49,680 --> 00:25:53,119 Speaker 1: Mass is turned directly into energy, just like E equals 521 00:25:53,200 --> 00:25:54,640 mc squared says. 522 00:25:54,480 --> 00:25:57,759 Speaker 2: And the reverse is also profoundly important. It's called pair production, 523 00:25:58,200 --> 00:26:02,079 where enough energy to high my energy photons colliding can 524 00:26:02,119 --> 00:26:05,039 spontaneously create a particle antiparticle pair. 525 00:26:05,279 --> 00:26:08,400 Speaker 1: And this cycle of creation and annihilation was just constant 526 00:26:08,480 --> 00:26:10,279 during the first moments after the Big Bang. 527 00:26:10,400 --> 00:26:13,680 Speaker 2: For every particle of matter created, there was a corresponding 528 00:26:13,720 --> 00:26:15,880 particle of antimatter popping into. 529 00:26:15,680 --> 00:26:19,160 Speaker 1: Existence, which raises the single most important cosmic puzzle. If 530 00:26:19,200 --> 00:26:21,960 equal amounts of matter and antimatter were created, they should 531 00:26:21,960 --> 00:26:24,920 have annihilated each other perfectly. The universe today should be 532 00:26:24,960 --> 00:26:25,759 pure energy. 533 00:26:25,920 --> 00:26:29,039 Speaker 2: But we exist, which means matter won the battle. 534 00:26:29,200 --> 00:26:32,559 Speaker 1: This is the great cosmic puzzle, the matter antimatter asymmetry. 535 00:26:32,920 --> 00:26:36,279 Speaker 2: We exist because there was a minuscule, tiny imbalance in 536 00:26:36,319 --> 00:26:40,200 the early universe where processes favored the survival of matter 537 00:26:40,279 --> 00:26:41,160 over antimatter. 538 00:26:41,359 --> 00:26:44,640 Speaker 1: The sources estimate that only one matter particle per billion 539 00:26:44,720 --> 00:26:47,039 survived that intense annihilation. 540 00:26:46,599 --> 00:26:49,559 Speaker 2: Era one in a billion. That minuscule residue is the 541 00:26:49,759 --> 00:26:54,680 entire makeup of our current matter dominated universe, all the galaxies, 542 00:26:54,759 --> 00:26:56,440 all the stars, and us. 543 00:26:56,839 --> 00:26:59,759 Speaker 1: That scale is just staggering everything we see as the 544 00:26:59,759 --> 00:27:02,279 rest of a one in a billion survival rate. 545 00:27:02,359 --> 00:27:05,440 Speaker 2: And the million dollar question, the one that keeps cosmologists 546 00:27:05,440 --> 00:27:09,160 sub at night, is why did matter win out? What 547 00:27:09,359 --> 00:27:11,480 caused that tiny asymmetry to occur? 548 00:27:11,759 --> 00:27:15,440 Speaker 1: That remains one of the central unsolved mysteries in physics today, a. 549 00:27:15,359 --> 00:27:18,720 Speaker 2: Massive ongoing area of research that seeks to explain why 550 00:27:18,759 --> 00:27:20,519 there is something rather than nothing. 551 00:27:20,599 --> 00:27:23,200 Speaker 1: Finally, let's tie this world altering discovery back to the 552 00:27:23,240 --> 00:27:26,720 man himself. Durraq was justly recognized, sharing the nineteen thirty 553 00:27:26,720 --> 00:27:29,880 three Nobel Prize with Schreudinger, and this story takes an 554 00:27:29,920 --> 00:27:31,640 unexpectedly sweet human turn. 555 00:27:31,880 --> 00:27:35,200 Speaker 2: It does remember Eugene Wigner, the physicists who described Drac's 556 00:27:35,240 --> 00:27:38,160 lecture styles so dry. He became a friend of Drak's, 557 00:27:38,559 --> 00:27:41,319 and in nineteen thirty four he introduced Iraq to his sister, 558 00:27:41,759 --> 00:27:42,920 Marget Wigner. 559 00:27:42,640 --> 00:27:46,079 Speaker 1: And this is the ultimate particle antiparticle love story. They 560 00:27:46,079 --> 00:27:50,039 were described as having completely almost comically opposite personalities. 561 00:27:50,200 --> 00:27:55,400 Speaker 2: Paul Durak had notoriously low empathy and was famously quiet. Marget, 562 00:27:55,440 --> 00:27:58,640 by contrast, had buckets of empathy and was constantly talking. 563 00:27:59,079 --> 00:28:02,839 Speaker 1: Their marriage was a synthesis of opposites, Paul driven by 564 00:28:02,880 --> 00:28:06,559 the cold purity of mathematical beauty and Marget driven by 565 00:28:06,559 --> 00:28:08,799 the warmth and messiness of human connection. 566 00:28:09,160 --> 00:28:12,319 Speaker 2: The source shares that wonderful line, summing up their dynamic. 567 00:28:12,839 --> 00:28:14,839 He gave her status, she gave him a life. 568 00:28:14,880 --> 00:28:18,599 Speaker 1: It was one particle antiparticle pair that never annihilated, but 569 00:28:18,680 --> 00:28:22,559 instead stabilized into a unique whole. A remarkable ending for 570 00:28:22,640 --> 00:28:25,480 a man who used pure logic to unlock the mirrored 571 00:28:25,519 --> 00:28:26,680 structure of reality. 572 00:28:27,000 --> 00:28:30,519 Speaker 2: Reflect on the sheer audacity of that achievement. Direct's drive 573 00:28:30,599 --> 00:28:34,359 for beauty forced reality to conform to his mathematics, predicting 574 00:28:34,440 --> 00:28:37,559 two fundamental aspects of nature that were totally unknown to 575 00:28:37,640 --> 00:28:38,319 him at the time. 576 00:28:38,599 --> 00:28:41,039 Speaker 1: So what does this all mean for you? The story 577 00:28:41,079 --> 00:28:43,920 of Derek is the ultimate testament to the power of 578 00:28:44,000 --> 00:28:48,240 theoretical physics. He was famous for prioritizing mathematical beauty overfitting 579 00:28:48,279 --> 00:28:51,720 the preliminary experimental data in the realm of fundamental science 580 00:28:51,720 --> 00:28:54,319 in the deepest searches for truth. Which path do you 581 00:28:54,359 --> 00:28:59,319 believe leads to the most profound breakthroughs. Prioritizing empirical observation 582 00:28:59,400 --> 00:29:03,880 and evidence, or trusting entirely in mathematical elegance and symmetry. 583 00:29:04,160 --> 00:29:06,000 Let us know what you think and what your stand is.