WEBVTT 00:00:00.000 --> 00:00:01.980 It's amazing when you really think about it. 00:00:02.399 --> 00:00:05.379 Everything we see around us, like everything, 00:00:05.900 --> 00:00:08.099 this table, these microphones, even us, you and 00:00:08.099 --> 00:00:10.960 me, is made from the same tiny building blocks, 00:00:11.699 --> 00:00:14.599 protons, neutrons, and electrons. Yeah, it really 00:00:14.599 --> 00:00:17.570 is. And it doesn't stop there. We look out into 00:00:17.570 --> 00:00:21.010 space at planets, stars, even entire galaxies, 00:00:21.050 --> 00:00:23.429 and as far as we can tell, it's the same recipe 00:00:23.429 --> 00:00:26.309 everywhere. You've got these three basic ingredients, 00:00:26.370 --> 00:00:28.589 and they're just arranged in countless ways. 00:00:28.829 --> 00:00:32.009 Countless ways, exactly. But there's a big mystery 00:00:32.009 --> 00:00:34.429 here. You see, for decades, scientists have been 00:00:34.429 --> 00:00:36.829 searching for something else. Something like 00:00:36.829 --> 00:00:39.909 a mirror image of all this familiar matter. We 00:00:39.909 --> 00:00:42.270 call it anti -matter. And it's a really fundamental 00:00:42.270 --> 00:00:45.210 question. Why is the universe so chock full of 00:00:45.210 --> 00:00:47.969 matter like a us. But we haven't seen much of 00:00:47.969 --> 00:00:51.130 this antimatter counterpart. Early on, physics 00:00:51.130 --> 00:00:53.609 seemed to suggest a beautiful symmetry, almost 00:00:53.609 --> 00:00:55.210 like the universe should have been made with 00:00:55.210 --> 00:00:57.770 equal parts of matter and antimatter. It's a 00:00:57.770 --> 00:01:00.310 real head -scratcher. So for this deep dive, 00:01:00.710 --> 00:01:03.170 we're going on a journey into the world of antimatter. 00:01:03.689 --> 00:01:06.349 We'll explore what it is, some of its weirder 00:01:06.349 --> 00:01:08.590 characteristics, and the groundbreaking research 00:01:08.590 --> 00:01:11.769 going on at places like CERN. all in an effort 00:01:11.769 --> 00:01:14.629 to unpack this cosmic imbalance. And just to 00:01:14.629 --> 00:01:16.349 be clear, we're not talking about some science 00:01:16.349 --> 00:01:18.670 fiction fantasy here. No, not at all. Antimatter 00:01:18.670 --> 00:01:21.790 is real. It's a solid part of our best understanding 00:01:21.790 --> 00:01:24.750 of physics, something we've known about for almost 00:01:24.750 --> 00:01:27.549 a century now. That's right. The story really 00:01:27.549 --> 00:01:31.069 takes off in 1932. Carl Anderson was working 00:01:31.069 --> 00:01:33.549 at Caltech using something called a cloud chamber. 00:01:33.609 --> 00:01:35.750 Oh the cloud chamber classic. He was studying 00:01:35.750 --> 00:01:38.370 cosmic rays these incredibly energetic particles 00:01:38.370 --> 00:01:40.530 that are constantly bombarding Earth from space. 00:01:41.090 --> 00:01:43.569 See in a cloud chamber charged particles leave 00:01:43.569 --> 00:01:46.109 a trail and when you put a magnet around it they 00:01:46.109 --> 00:01:48.090 curve. Right like the little bar magnets we used 00:01:48.090 --> 00:01:50.590 to play with. Exactly. The direction of that 00:01:50.590 --> 00:01:52.489 curve tells you if it's a positive or negative 00:01:52.489 --> 00:01:55.230 charge and how much it curves tells you how massive 00:01:55.230 --> 00:01:58.879 the particle is. So Anderson saw particles curving 00:01:58.879 --> 00:02:01.680 one way, electrons negatively charged, no surprise 00:02:01.680 --> 00:02:04.620 there. But then he saw something strange. These 00:02:04.620 --> 00:02:08.199 other particles, positively charged, but way 00:02:08.199 --> 00:02:10.620 too light to be protons. In fact, they had the 00:02:10.620 --> 00:02:13.120 same mass as electrons, but with a positive charge. 00:02:13.560 --> 00:02:16.219 Whoa, like finding a mirror image. A plus instead 00:02:16.219 --> 00:02:19.159 of a minus. Exactly. That's how we first detected 00:02:19.159 --> 00:02:21.710 antimatter. Those anti -electrons we now call 00:02:21.710 --> 00:02:25.090 positrons. A monumental discovery. And he absolutely 00:02:25.090 --> 00:02:27.370 deserved the Nobel Prize he got for it in 36. 00:02:27.509 --> 00:02:29.650 Definitely a Nobel -worthy discovery. But here's 00:02:29.650 --> 00:02:31.689 the kicker. These positrons weren't a complete 00:02:31.689 --> 00:02:33.590 surprise, were they? You're right. A few years 00:02:33.590 --> 00:02:36.729 before, around 1928, Paul Dirac, this brilliant 00:02:36.729 --> 00:02:39.550 physicist, had actually predicted them. He was 00:02:39.550 --> 00:02:41.530 working on a way to describe electrons using 00:02:41.530 --> 00:02:44.110 both quantum mechanics and Einstein's theory 00:02:44.110 --> 00:02:47.030 of special relativity. A tough problem. Trying 00:02:47.030 --> 00:02:50.259 to mesh those two giants. Yeah. And when he did, 00:02:50.599 --> 00:02:53.300 his math showed something wild. There couldn't 00:02:53.300 --> 00:02:56.360 just be one type of electron. The equations only 00:02:56.360 --> 00:02:58.520 worked if there were two. One with a negative 00:02:58.520 --> 00:03:00.979 charge, that's our everyday electron, and another 00:03:00.979 --> 00:03:03.939 with a positive charge, the positron. The math 00:03:03.939 --> 00:03:06.439 forced the positron into existence. Pretty much. 00:03:06.620 --> 00:03:08.840 This mathematical object he found, called the 00:03:08.840 --> 00:03:11.599 Dirac Spiner, basically said, hey, there should 00:03:11.599 --> 00:03:14.319 be a twin particle for every electron, but with 00:03:14.319 --> 00:03:17.099 the opposite charge. He predicted antimatter 00:03:17.099 --> 00:03:19.770 before anyone had ever seen it. Amazing, right? 00:03:19.969 --> 00:03:22.289 It really is and it gets even crazier this twin 00:03:22.289 --> 00:03:24.509 particle idea. This isn't just about electrons 00:03:24.509 --> 00:03:26.990 Absolutely, not there's an antimatter twin for 00:03:26.990 --> 00:03:30.110 every type of particle exactly for every single 00:03:30.110 --> 00:03:32.849 one You've got quarks which make up protons and 00:03:32.849 --> 00:03:34.530 neutrons. Well, they're anti quarks, too They 00:03:34.530 --> 00:03:36.789 team up to make anti protons and anti neutrons 00:03:36.789 --> 00:03:39.090 and you can go even further these antimatter 00:03:39.090 --> 00:03:41.909 building blocks can actually combine To form 00:03:41.909 --> 00:03:45.370 whole anti atoms even anti molecules. Okay mind 00:03:45.370 --> 00:03:48.310 blown So in theory you could have an entire planet 00:03:48.620 --> 00:03:52.379 a star, maybe even a galaxy, all made of antimatter. 00:03:52.919 --> 00:03:54.840 And if you saw it through a telescope, you wouldn't 00:03:54.840 --> 00:03:57.080 be able to tell it was antimatter just from looking. 00:03:57.400 --> 00:04:00.280 Nope, not at all. An antimatter planet, if we 00:04:00.280 --> 00:04:03.159 could observe one from afar, would look, behave, 00:04:03.379 --> 00:04:05.500 and even interact gravitationally, just like 00:04:05.500 --> 00:04:08.560 any other planet we see. Whoa. It just really 00:04:08.560 --> 00:04:10.960 drives home this big question, this fundamental 00:04:10.960 --> 00:04:14.789 asymmetry. If matter and antimatter are so similar, 00:04:14.990 --> 00:04:17.290 why is the universe we see basically just matter? 00:04:17.589 --> 00:04:19.269 That's the million dollar question, isn't it? 00:04:19.470 --> 00:04:22.629 This imbalance, which scientists call the baryonic 00:04:22.629 --> 00:04:25.170 asymmetry of the universe, has been a driving 00:04:25.170 --> 00:04:27.829 force behind research for a long time. And that's 00:04:27.829 --> 00:04:30.310 where places like CERN come in. With their huge 00:04:30.310 --> 00:04:32.470 particle accelerators, they're able to create, 00:04:32.750 --> 00:04:35.189 trap, and study antimatter in ways we never could 00:04:35.189 --> 00:04:37.050 before. Yeah, those guys are pushing the boundaries 00:04:37.050 --> 00:04:39.720 of what we know. So we know it exists, but what 00:04:39.720 --> 00:04:42.319 makes antimatter tick? How does it behave compared 00:04:42.319 --> 00:04:44.980 to the regular stuff? Well, we've studied isolated 00:04:44.980 --> 00:04:47.660 antiparticles, and their fundamental properties, 00:04:48.060 --> 00:04:50.579 like their mass, are identical to their matter 00:04:50.579 --> 00:04:53.879 partners. A positron weighs the same as an electron, 00:04:54.339 --> 00:04:56.800 an antiproton the same as a proton. It's a perfect 00:04:56.800 --> 00:04:58.920 mirror image as far as mass is concerned. But 00:04:58.920 --> 00:05:01.000 what about their behavior? How they interact 00:05:01.000 --> 00:05:04.360 with the forces of nature? Let's start with electromagnetism. 00:05:04.620 --> 00:05:08.100 That's the force responsible for, well, electricity 00:05:08.100 --> 00:05:10.779 and magnetism and how charged particles interact. 00:05:10.939 --> 00:05:12.839 The one we're most familiar with in our daily 00:05:12.839 --> 00:05:15.680 lives. Exactly. Experiments show antiparticles 00:05:15.680 --> 00:05:18.360 act exactly like the theory predicts, just with 00:05:18.360 --> 00:05:20.779 the opposite charge. Remember Anderson's cloud 00:05:20.779 --> 00:05:23.620 chamber. Positrons curving the opposite way to 00:05:23.620 --> 00:05:25.899 electrons. That's the opposite charge in action. 00:05:26.100 --> 00:05:28.279 Right. But there are other forces at play too, 00:05:28.379 --> 00:05:30.759 right? Gravity, the weak nuclear force, the strong 00:05:30.759 --> 00:05:33.660 nuclear force. Is it there where things get a 00:05:33.660 --> 00:05:36.439 bit less symmetrical? You're getting to the heart 00:05:36.439 --> 00:05:39.339 of it. Things get really interesting when we 00:05:39.339 --> 00:05:43.019 look at the weak nuclear force. Back in the 50s 00:05:43.019 --> 00:05:45.899 and 60s, physicists found some surprising differences 00:05:45.899 --> 00:05:48.100 in how it treats particles and antiparticles. 00:05:48.660 --> 00:05:50.899 The first one had to do with a property called 00:05:50.899 --> 00:05:54.870 handedness, or chirality. Handedness. I know 00:05:54.870 --> 00:05:57.569 my right hand from my left, but for tiny particles. 00:05:57.790 --> 00:05:59.850 Yeah, it's a bit abstract. Think of it like this. 00:06:00.170 --> 00:06:03.110 Ordinary particles, the matter kind, only feel 00:06:03.110 --> 00:06:05.769 the weak force if they have a specific orientation, 00:06:06.050 --> 00:06:09.449 like a left -handed spin, if you will. And antiparticles 00:06:09.449 --> 00:06:12.029 only interact if they're right -handed. So it's 00:06:12.029 --> 00:06:14.170 like the weak force is a bit picky. Yeah, you 00:06:14.170 --> 00:06:16.089 could say that. It only shakes hands with certain 00:06:16.089 --> 00:06:18.310 particles, depending on their handedness. That's 00:06:18.310 --> 00:06:20.029 wild, but it gets even weirder, right? It's not 00:06:20.029 --> 00:06:22.329 just that it interacts, but the strength of the 00:06:22.329 --> 00:06:25.529 interaction is different, too. You got it. The 00:06:25.529 --> 00:06:28.370 second, even more surprising finding was that 00:06:28.370 --> 00:06:31.410 this difference in handedness also meant a difference 00:06:31.410 --> 00:06:34.129 in the strength of the weak force. Right -handed 00:06:34.129 --> 00:06:36.250 antiparticles don't just interact differently 00:06:36.250 --> 00:06:38.829 with the weak force. They actually experience 00:06:38.829 --> 00:06:41.170 a different strength of this interaction compared 00:06:41.170 --> 00:06:44.350 to left -handed ordinary particles. Whoa, okay. 00:06:44.870 --> 00:06:47.269 So what does this all mean in the grand scheme 00:06:47.269 --> 00:06:50.189 of things? What are the real -world consequences 00:06:50.189 --> 00:06:53.470 of this difference in strength? Well, one way 00:06:53.470 --> 00:06:56.389 this plays out is in radioactive decay. That's 00:06:56.389 --> 00:06:58.629 a process governed by the weak force. Because 00:06:58.629 --> 00:07:00.649 of this difference in strength, the chances of 00:07:00.649 --> 00:07:03.050 a nucleus decaying radioactively are slightly 00:07:03.050 --> 00:07:05.529 different for regular matter compared to antimatter. 00:07:05.750 --> 00:07:07.670 So the mirror isn't perfectly reflecting here. 00:07:07.870 --> 00:07:11.290 Exactly. This subtle but crucial asymmetry was 00:07:11.290 --> 00:07:14.290 first observed back in 1963 by James Cronin and 00:07:14.290 --> 00:07:16.930 Valfitch and actually won them a Nobel Prize. 00:07:17.370 --> 00:07:19.970 Another Nobel -worthy discovery. So I imagine 00:07:19.970 --> 00:07:21.629 when this asymmetry was first discovered there 00:07:21.629 --> 00:07:23.860 was a lot of excitement. This difference in the 00:07:23.860 --> 00:07:25.720 weak force wasn't seen as a potential answer 00:07:25.720 --> 00:07:28.100 to this matter -antimatter imbalance. That was 00:07:28.100 --> 00:07:30.240 definitely the hope. You know, maybe the weak 00:07:30.240 --> 00:07:33.300 force had this slight bias towards creating matter 00:07:33.300 --> 00:07:36.160 over antimatter in the early universe. The weak 00:07:36.160 --> 00:07:39.500 force nudged the scales. Maybe, but the math 00:07:39.500 --> 00:07:42.540 didn't quite add up. Turns out this difference, 00:07:42.759 --> 00:07:45.120 while important, wasn't big enough to explain 00:07:45.120 --> 00:07:47.779 the huge amount of matter we see and the lack 00:07:47.779 --> 00:07:50.560 of antimatter. It's like finding a tiny crack 00:07:50.560 --> 00:07:53.180 in the mirror, but not the huge shatter that 00:07:53.180 --> 00:07:56.300 would explain everything. So great discovery, 00:07:56.660 --> 00:07:59.319 Nobel Prize earned, but the ultimate mystery 00:07:59.319 --> 00:08:01.540 remained. Okay, so the weak force isn't the whole 00:08:01.540 --> 00:08:03.800 story. What about the strong force? That's the 00:08:03.800 --> 00:08:05.879 one that binds protons and neutrons together 00:08:05.879 --> 00:08:08.560 in the nucleus. Super strong, as the name suggests. 00:08:08.860 --> 00:08:10.240 You would think, following the pattern with the 00:08:10.240 --> 00:08:11.800 weak force, that there might be some difference 00:08:11.800 --> 00:08:13.639 in how left -handed particles and right -handed 00:08:13.639 --> 00:08:16.139 antiparticles feel the strong force, right? Yeah, 00:08:16.139 --> 00:08:18.670 seems logical. Well, once again, antimatter threw 00:08:18.670 --> 00:08:21.529 us a curveball. Every experiment, and I mean 00:08:21.529 --> 00:08:24.730 every single one, shows the strong force doesn't 00:08:24.730 --> 00:08:26.850 care if it's dealing with matter or antimatter. 00:08:26.910 --> 00:08:29.730 It treats them exactly the same. No asymmetry, 00:08:29.870 --> 00:08:32.789 no difference in strength, nothing. So the strong 00:08:32.789 --> 00:08:35.529 force is totally blind to this matter -antimatter 00:08:35.529 --> 00:08:38.210 difference. Blind is a bat. Which brings us to 00:08:38.210 --> 00:08:41.629 gravity, that final fundamental force. And this 00:08:41.629 --> 00:08:43.549 is where things are getting really interesting 00:08:43.549 --> 00:08:46.899 at CERN. They're trying to nail down, once and 00:08:46.899 --> 00:08:49.919 for all, if gravity acts differently on matter 00:08:49.919 --> 00:08:52.379 and antimatter. Absolutely, it's a really exciting 00:08:52.379 --> 00:08:55.019 area of research. But it sounds like most physicists 00:08:55.019 --> 00:08:57.120 are betting it won't, right? That's the common 00:08:57.120 --> 00:09:00.340 assumption. Think back to Galileo dropping objects 00:09:00.340 --> 00:09:03.679 from the Leaning Tower of Pisa, or Newton's law 00:09:03.679 --> 00:09:06.360 of universal gravitation. The key takeaway is 00:09:06.360 --> 00:09:08.340 that gravity doesn't care what something's made 00:09:08.340 --> 00:09:11.769 of, just how much mass it has. A cannonball and 00:09:11.769 --> 00:09:14.950 a feather in a vacuum will fall at the same rate. 00:09:14.970 --> 00:09:17.269 Right, a classic physics demo. And this is a 00:09:17.269 --> 00:09:19.610 cornerstone of Einstein's theory of general relativity, 00:09:19.769 --> 00:09:22.409 his equivalence principle. It says that the mass 00:09:22.409 --> 00:09:24.309 that determines how much something resists being 00:09:24.309 --> 00:09:26.429 pushed, its inertia, and the mass that makes 00:09:26.429 --> 00:09:29.470 it feel gravity are the same thing. So, in a 00:09:29.470 --> 00:09:31.330 gravitational field, everything falls at the 00:09:31.330 --> 00:09:34.169 same rate, no matter what it's made of. So, given 00:09:34.169 --> 00:09:36.350 this well -established principle, why bother 00:09:36.350 --> 00:09:38.850 trying to measure gravity's effect on antimatter? 00:09:39.039 --> 00:09:41.080 It seems like a huge undertaking for something 00:09:41.080 --> 00:09:43.220 we think we already know the answer to. Well, 00:09:43.500 --> 00:09:45.940 there are a couple of good reasons. First, there's 00:09:45.940 --> 00:09:49.679 that mystery of the baryonic asymmetry, the matter 00:09:49.679 --> 00:09:53.000 -antimatter imbalance. We have to explore all 00:09:53.000 --> 00:09:55.500 avenues, even the unlikely ones. Leave no stone 00:09:55.500 --> 00:09:58.720 unturned. Exactly. The second reason is a bit 00:09:58.720 --> 00:10:02.110 more speculative. Some theories trying to explain 00:10:02.110 --> 00:10:05.870 dark matter and dark energy to big cosmic mysteries 00:10:05.870 --> 00:10:08.789 suggest that antimatter might actually have a 00:10:08.789 --> 00:10:11.509 negative gravitational charge. Segetive gravitational 00:10:11.509 --> 00:10:13.730 charge, meaning it would fall up, wouldn't that 00:10:13.730 --> 00:10:15.710 be a sight to see? It would defy our everyday 00:10:15.710 --> 00:10:19.090 experience for sure. So, to test this, a few 00:10:19.090 --> 00:10:20.990 very sophisticated experiments are running at 00:10:20.990 --> 00:10:25.139 CERN. Aegis, GBAR, and LFA. In fact, the LFA 00:10:25.139 --> 00:10:27.220 team recently published some big findings in 00:10:27.220 --> 00:10:29.500 the journal Nature, giving us actual data on 00:10:29.500 --> 00:10:31.899 how antimatter accelerates under Earth's gravity. 00:10:32.700 --> 00:10:35.039 After decades of assumptions, we finally have 00:10:35.039 --> 00:10:36.799 hard evidence to work with. It must have been 00:10:36.799 --> 00:10:38.879 a huge moment finally getting some concrete data 00:10:38.879 --> 00:10:41.740 after all this time. But how did they manage 00:10:41.740 --> 00:10:44.799 to measure something so incredibly subtle? It 00:10:44.799 --> 00:10:47.419 sounds impossibly difficult. Oh, it was a phenomenal 00:10:47.419 --> 00:10:50.820 feat. It started with generating a beam of positrons. 00:10:50.919 --> 00:10:53.570 Remember those anti -electrons? from a radioactive 00:10:53.570 --> 00:10:57.409 form of sodium, sodium -22. Now, when positrons 00:10:57.409 --> 00:10:59.710 meet normal matter, they usually annihilate each 00:10:59.710 --> 00:11:03.149 other in a burst of energy. Gone. Exactly. But 00:11:03.149 --> 00:11:06.149 a tiny fraction of these positrons actually survive. 00:11:06.529 --> 00:11:08.429 And the researchers managed to capture those 00:11:08.429 --> 00:11:10.970 survivors, cool them down to ridiculously low 00:11:10.970 --> 00:11:13.370 temperatures, and then trap them using carefully 00:11:13.370 --> 00:11:15.909 arranged electric and magnetic fields. But you 00:11:15.909 --> 00:11:17.950 said earlier that measuring gravity's effect 00:11:17.950 --> 00:11:20.210 on individual positrons is almost impossible, 00:11:20.389 --> 00:11:22.450 right? They're just too light, and even the tiniest 00:11:22.450 --> 00:11:24.429 electromagnetic fields could mess everything 00:11:24.429 --> 00:11:26.269 up. You're absolutely right. So they needed a 00:11:26.269 --> 00:11:28.450 trick, and it was a brilliant one. They took 00:11:28.450 --> 00:11:31.919 those trapped positrons and combined with antiprotons 00:11:31.919 --> 00:11:35.539 to make neutral anti -hydrogen atoms. Antiprotons 00:11:35.539 --> 00:11:37.899 are made by smashing high -energy protons into 00:11:37.899 --> 00:11:40.309 a metal target. And since these new anti -hydrogen 00:11:40.309 --> 00:11:42.909 atoms are neutral, meaning no net electric charge, 00:11:43.210 --> 00:11:45.509 they're way less affected by stray electromagnetic 00:11:45.509 --> 00:11:48.049 fields, making them ideal for gravity experiments. 00:11:48.350 --> 00:11:50.389 Like trying to measure the fall of a feather 00:11:50.389 --> 00:11:52.769 in a hurricane, but now you've somehow managed 00:11:52.769 --> 00:11:55.169 to shield the feather from the wind. That's a 00:11:55.169 --> 00:11:57.629 great analogy. So now they have these anti -hydrogen 00:11:57.629 --> 00:12:00.289 atoms, the neutral ones, but how do they isolate 00:12:00.289 --> 00:12:02.009 them and actually measure the effect of gravity? 00:12:02.250 --> 00:12:04.049 Yeah, especially since gravity is such a weak 00:12:04.049 --> 00:12:06.580 force compared to the other ones. They use a 00:12:06.580 --> 00:12:09.379 special chamber with a near -perfect vacuum to 00:12:09.379 --> 00:12:12.960 minimize unwanted interactions. Inside, the anti 00:12:12.960 --> 00:12:15.379 -hydrogen atoms are trapped, using a complex 00:12:15.379 --> 00:12:18.000 arrangement of magnetic fields, sort of like 00:12:18.000 --> 00:12:21.360 a magnetic bottle. Then... They carefully, and 00:12:21.360 --> 00:12:24.659 I mean very carefully, weaken the vertical magnetic 00:12:24.659 --> 00:12:26.500 fields that are holding those anti -hydrogen 00:12:26.500 --> 00:12:28.799 atoms. What does that do? Well, because those 00:12:28.799 --> 00:12:30.799 atoms are always jiggling around due to their 00:12:30.799 --> 00:12:33.539 thermal energy, this weakening of the field allows 00:12:33.539 --> 00:12:36.500 them to slowly escape, either from the top or 00:12:36.500 --> 00:12:38.639 the bottom of the chamber, over about 20 seconds. 00:12:38.899 --> 00:12:41.399 I see. So it's like tilting that magnetic bottle 00:12:41.399 --> 00:12:43.799 ever so slightly, allowing them to dribble out 00:12:43.799 --> 00:12:46.960 one by one. Exactly. Now here's the crucial part. 00:12:47.049 --> 00:12:49.950 When one of these escaping anti -hydrogen atoms 00:12:49.950 --> 00:12:52.190 hits the wall of the chamber, which is made of 00:12:52.190 --> 00:12:55.309 regular matter, they annihilate, releasing a 00:12:55.309 --> 00:12:58.350 burst of light. Ah, that poof again. Yep, but 00:12:58.350 --> 00:13:01.509 a very useful poof. By carefully counting the 00:13:01.509 --> 00:13:03.409 number of annihilation events happening at the 00:13:03.409 --> 00:13:05.809 top versus the bottom of the chamber, they can 00:13:05.809 --> 00:13:07.889 figure out which way gravity is pulling those 00:13:07.889 --> 00:13:10.529 anti -hydrogen atoms. Okay, so if gravity is 00:13:10.529 --> 00:13:12.710 pulling antimatter down, like normal matter, 00:13:12.830 --> 00:13:14.809 they should see more annihilations at the bottom 00:13:14.809 --> 00:13:17.559 of the chamber. You got it. To make sure they 00:13:17.559 --> 00:13:19.440 were interpreting things correctly, they ran 00:13:19.440 --> 00:13:22.700 simulations. These simulations show that if anti 00:13:22.700 --> 00:13:25.480 -hydrogen experiences normal gravity, they'd 00:13:25.480 --> 00:13:28.139 expect about 85 % of the annihilations to happen 00:13:28.139 --> 00:13:30.940 at the bottom. If antimatter was falling upwards, 00:13:31.059 --> 00:13:34.080 only 20 % would be at the bottom. And if gravity 00:13:34.080 --> 00:13:37.299 had no effect at all, it would be about 50 -50, 00:13:37.700 --> 00:13:40.100 with some slight variation due to imperfections 00:13:40.100 --> 00:13:42.960 in the experiment. Drumroll, please. What did 00:13:42.960 --> 00:13:45.679 they actually see? The results were pretty clear. 00:13:45.799 --> 00:13:48.759 Roughly 75 % of the anti -hydrogen atoms that 00:13:48.759 --> 00:13:50.940 escaped ended up annihilating at the bottom of 00:13:50.940 --> 00:13:54.080 the chamber. That strongly points to normal downward 00:13:54.080 --> 00:13:56.480 gravity for antimatter, just like we'd expect 00:13:56.480 --> 00:13:58.820 for regular stuff. Okay, that seems pretty convincing. 00:13:59.179 --> 00:14:00.840 But I imagine they didn't just stop there, did 00:14:00.840 --> 00:14:03.610 they? Oh no. To double check and eliminate any 00:14:03.610 --> 00:14:05.909 potential biases in their setup, they did the 00:14:05.909 --> 00:14:08.730 experiment multiple times, each time adding a 00:14:08.730 --> 00:14:11.169 small controlled magnetic force, either pushing 00:14:11.169 --> 00:14:13.649 the anti -hydrogen atoms up or down to simulate 00:14:13.649 --> 00:14:15.450 different gravity conditions. So like adding 00:14:15.450 --> 00:14:18.870 a little extra push or pull? Exactly. Then they 00:14:18.870 --> 00:14:20.730 compared the results from these different runs 00:14:20.730 --> 00:14:23.669 to their simulations for various gravity scenarios. 00:14:24.169 --> 00:14:26.450 The best match, the one that fit the data the 00:14:26.450 --> 00:14:29.210 closest, was for downward gravity acting just 00:14:29.210 --> 00:14:31.370 like it does on regular matter. But you said 00:14:31.370 --> 00:14:34.049 their best estimate for the gravitational acceleration 00:14:34.049 --> 00:14:36.889 was slightly lower than the usual 9 .8 meters 00:14:36.889 --> 00:14:39.169 per second squared where you stay, right? Yes. 00:14:39.429 --> 00:14:42.090 It came out to about 0 .75 g. But here's the 00:14:42.090 --> 00:14:44.649 important thing. Their measurements had uncertainties, 00:14:44.950 --> 00:14:47.029 which are super important in any experiment. 00:14:47.350 --> 00:14:49.429 You always need to know how precise your result 00:14:49.429 --> 00:14:52.690 is. The infamous error bars. Right. After accounting 00:14:52.690 --> 00:14:55.470 for everything, their best estimate, with error 00:14:55.470 --> 00:15:00.330 bars included, was 0 .75 g. plus or minus 0 .13g 00:15:00.330 --> 00:15:02.929 due to potential systematic errors, and plus 00:15:02.929 --> 00:15:06.429 or minus 0 .16g from random statistical fluctuations. 00:15:07.049 --> 00:15:09.789 This means a full 1g acceleration is still comfortably 00:15:09.789 --> 00:15:12.090 within their margin of error, completely compatible 00:15:12.090 --> 00:15:14.389 with their findings. So while future experiments 00:15:14.389 --> 00:15:16.710 might refine this measurement, it's safe to say 00:15:16.710 --> 00:15:19.450 this groundbreaking work effectively rules out 00:15:19.450 --> 00:15:22.090 those more outlandish ideas of antimatter falling 00:15:22.090 --> 00:15:26.039 up. Pretty much. It seems antimatter while strange 00:15:26.039 --> 00:15:29.200 and exotic, still obeys the same gravitational 00:15:29.200 --> 00:15:32.519 rules as the rest of us. So, to summarize, we 00:15:32.519 --> 00:15:35.200 know antimatter is real. It has the same mass 00:15:35.200 --> 00:15:37.820 but opposite charge as its matter counterparts. 00:15:38.519 --> 00:15:40.820 Its electromagnetic interactions are as expected, 00:15:41.240 --> 00:15:43.419 but the weak force treats it a bit differently, 00:15:43.679 --> 00:15:45.860 though not enough to explain the matter dominance 00:15:45.860 --> 00:15:48.879 of the universe. And now, it seems, gravity plays 00:15:48.879 --> 00:15:51.639 by the same rules for both matter and antimatter. 00:15:51.700 --> 00:15:54.440 But that still leaves the big question unanswered. 00:15:54.539 --> 00:15:58.019 Why are we here, in a universe made almost entirely 00:15:58.019 --> 00:16:00.899 of matter? It's a puzzle that continues to baffle 00:16:00.899 --> 00:16:04.080 physicists. If the laws of physics, as far as 00:16:04.080 --> 00:16:06.419 we can tell, are mostly symmetrical for matter 00:16:06.419 --> 00:16:08.759 and antimatter, then the overwhelming presence 00:16:08.759 --> 00:16:10.940 of matter in the universe is a huge mystery. 00:16:11.320 --> 00:16:13.559 It suggests we might be missing something fundamental 00:16:13.559 --> 00:16:16.120 in our understanding of physics, or perhaps the 00:16:16.120 --> 00:16:17.879 very beginning of the universe, the Big Bang 00:16:17.879 --> 00:16:20.269 itself. started with an imbalance baked right 00:16:20.269 --> 00:16:22.769 in. A huge imbalance playing out over billions 00:16:22.769 --> 00:16:24.590 of years. It's a lot to wrap your head around. 00:16:24.789 --> 00:16:27.669 It is. But that's the beauty of science. It's 00:16:27.669 --> 00:16:29.750 a never -ending quest to understand the universe 00:16:29.750 --> 00:16:32.830 and our place in it. Well said. A big thanks 00:16:32.830 --> 00:16:35.169 to you for diving into the fascinating world 00:16:35.169 --> 00:16:37.769 of antimatter with me. And to you, dear listener, 00:16:37.929 --> 00:16:40.330 I'll leave you with this. We've learned that 00:16:40.330 --> 00:16:42.899 antimatter, despite its weirdness, doesn't float 00:16:42.899 --> 00:16:46.019 away due to antigravity. It seems gravity keeps 00:16:46.019 --> 00:16:48.679 everything grounded, even the exotic stuff. But 00:16:48.679 --> 00:16:51.299 it's this very similarity that deepens the mystery. 00:16:52.039 --> 00:16:54.740 If matter and antimatter are so alike in so many 00:16:54.740 --> 00:16:57.139 ways, then what tipped the scales in the early 00:16:57.139 --> 00:16:59.379 universe? What made matter win out? What made 00:16:59.379 --> 00:17:01.639 our existence possible? It's a cosmic riddle. 00:17:01.919 --> 00:17:04.200 And maybe, just maybe, you'll be the one to help 00:17:04.200 --> 00:17:06.039 solve it. It would be quite a feat to unlock 00:17:06.039 --> 00:17:08.339 that mystery. Keep those brains buzzing, folks. 00:17:08.519 --> 00:17:10.460 And until next time, happy exploring.