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Remember they're real people with loved 0:01:30.560 --> 0:01:32.760 ones who need them to get home safely. Protect our 0:01:32.760 --> 0:01:34.880 cyclists and pedestrians because they're people too. 0:01:35.120 --> 0:01:35.679 Go safely. 0:01:35.760 --> 0:01:38.600 California from the California Office of Traffic Safety in Caltrans. 0:01:38.720 --> 0:01:41.160 When you pull up to game night, ay, all new Camri, 0:01:41.920 --> 0:01:49.200 but it's actually Bingo Night Minigolf anyone, It's a Camri. 0:01:49.000 --> 0:01:57.280 Five, the all new all hybrid Camri Toyota let's go places. 0:02:00.960 --> 0:02:04.160 I just think it's fascinating that it's such a fundamental 0:02:04.560 --> 0:02:08.440 force in the universe, right, Like it's basically the thing 0:02:08.520 --> 0:02:13.720 that builds galaxies and keeps planets moving right and gives 0:02:13.720 --> 0:02:15.600 structure to the entire cosmos. 0:02:15.960 --> 0:02:18.800 That's right. On the largest scale, it's actually the most 0:02:18.960 --> 0:02:22.079 important force. It's the reason why things look the way 0:02:22.080 --> 0:02:24.799 they do. It's the reason why our planet is round. 0:02:24.840 --> 0:02:26.960 It's the reason why we're on the planet. 0:02:27.200 --> 0:02:30.840 It's pretty important, and yet we don't know a lot 0:02:30.880 --> 0:02:34.280 about it, right, Like, there's some really deep and strange 0:02:34.600 --> 0:02:35.560 mysteries about it. 0:02:35.680 --> 0:02:37.960 On one hand, we have a theory which works really 0:02:37.960 --> 0:02:40.080 really well. On the other hand, we have questions about 0:02:40.080 --> 0:02:41.840 it which seems really really basic. 0:02:42.320 --> 0:02:44.760 And not only that, it's very different than all the 0:02:44.800 --> 0:02:46.320 other forces of nature. 0:02:46.880 --> 0:02:49.560 That's right, one of these things is not like the 0:02:49.639 --> 0:02:50.200 other ones. 0:03:08.840 --> 0:03:09.440 Hi am morhee. 0:03:09.480 --> 0:03:12.720 I'm a cartoonist and I'm Daniel. I'm a particle physicist. 0:03:12.960 --> 0:03:16.640 And this is our podcast Daniel and Jorge explain the universe. 0:03:16.400 --> 0:03:18.919 In which a cartoonist and a physicists try to figure 0:03:18.919 --> 0:03:22.239 out how to make the universe understandable to anybody. 0:03:22.600 --> 0:03:26.280 Yeah, and today on the podcast we are examining a 0:03:26.400 --> 0:03:37.360 very heavy topic, gravity and specifically why is gravity so. 0:03:37.560 --> 0:03:42.520 Weak and strange. Gravity, as we said earlier, is something 0:03:42.520 --> 0:03:45.120 which controls the structure of the universe. I mean, the 0:03:45.200 --> 0:03:47.440 reason the Solar System looks the way it does is 0:03:47.480 --> 0:03:50.280 because of gravity. The reason the Earth is round is 0:03:50.320 --> 0:03:53.200 because of gravity. The reason we have galaxies is because 0:03:53.200 --> 0:03:53.800 of gravity. 0:03:54.000 --> 0:03:56.680 The reason we weigh so much is because of gravity. Right, 0:03:56.720 --> 0:03:57.160 it's not my. 0:03:58.080 --> 0:04:02.080 Belt, No, that's because of late night cake eating. 0:04:03.840 --> 0:04:07.040 But it's such a fundamental force of nature, right, Like 0:04:07.080 --> 0:04:10.240 it's present in our everyday life. We spend a lot 0:04:10.280 --> 0:04:14.280 of time thinking about gravity, right, how not to fall down, 0:04:14.600 --> 0:04:17.280 how not to drop things, how to go up buildings, 0:04:17.320 --> 0:04:18.360 how to go down buildings. 0:04:18.440 --> 0:04:20.479 Right, that's right. It seems like one of the most 0:04:20.480 --> 0:04:23.040 important forces. I mean, if you ask people, you know, 0:04:23.200 --> 0:04:25.400 to name a force or what kind of forces the 0:04:25.480 --> 0:04:27.800 experience in their life, gravity is the one that's present 0:04:27.839 --> 0:04:28.400 in their lives. 0:04:28.480 --> 0:04:28.600 Right. 0:04:28.640 --> 0:04:31.479 You're climbing upstairs, you're fighting gravity, you trip, you fall down, 0:04:31.520 --> 0:04:34.599 you're feeling gravity. You look around you. The shape of 0:04:34.640 --> 0:04:37.799 things is controlled by gravity. And that's why it's particularly 0:04:37.880 --> 0:04:41.880 strange that gravity is the weakest force of all the 0:04:41.880 --> 0:04:45.000 forces we've discovered. It's by far the weakest. 0:04:45.200 --> 0:04:48.080 Yeah, it's really strange to hear you say that, Like, 0:04:48.160 --> 0:04:51.080 how can gravity be weak? Like, you know, like it's 0:04:51.200 --> 0:04:54.640 keeping the whole Earth together, it's making the entire planet 0:04:55.040 --> 0:04:58.160 swing around, go in a circle, basically. Right. Without gravity, 0:04:58.240 --> 0:04:59.720 we would just shoot off into space. 0:05:00.040 --> 0:05:03.000 That's right. It's a really strange situation. And there's other 0:05:03.040 --> 0:05:06.240 things about gravity we don't understand as well. It's really strange. 0:05:06.240 --> 0:05:08.839 It doesn't play well with the other forces. It's very, 0:05:08.920 --> 0:05:11.800 very weak. It's a total mystery to science, except that 0:05:11.839 --> 0:05:14.280 we have a theory which works beautifully right. We can 0:05:14.320 --> 0:05:17.799 calculate exactly how mercury orbits the sun. We can send 0:05:17.800 --> 0:05:20.600 things in outer space and know with to millimeter precision 0:05:20.680 --> 0:05:22.800 exactly where they're going to land. We have a working 0:05:22.839 --> 0:05:26.040 theory that we can use, right, but we don't understand 0:05:26.080 --> 0:05:28.560 it on a conceptual level. We have these basic, deep 0:05:28.640 --> 0:05:31.799 questions about what gravity is and how the universe works 0:05:31.800 --> 0:05:32.320 because of it. 0:05:32.560 --> 0:05:34.880 So it's a weird question, and maybe one of the 0:05:34.880 --> 0:05:37.800 people hadn't thought about before. So Daniel went out as 0:05:37.880 --> 0:05:40.479 usual and asked people on the street, why do you 0:05:40.520 --> 0:05:41.760 think gravity is so weak? 0:05:42.040 --> 0:05:44.240 Here's what a random selection of folks who were willing 0:05:44.279 --> 0:05:46.279 to talk to me on a Tuesday morning had to 0:05:46.279 --> 0:05:47.240 say about gravity. 0:05:47.760 --> 0:05:48.159 I don't know. 0:05:48.760 --> 0:05:51.600 I should don't know about that, all right. I thought 0:05:51.640 --> 0:05:56.160 it was a pretty strong force. I don't know, but yeah, because. 0:05:57.600 --> 0:06:00.240 It depends on the distance and it's long range one. 0:06:00.680 --> 0:06:02.640 So that's why we feel it very weak most of 0:06:02.720 --> 0:06:07.000 the time. Cool, No, Okay, I have no I'm sorry, 0:06:07.080 --> 0:06:08.120 it's not very fruitful. 0:06:08.680 --> 0:06:12.320 Hmmm, I have no idea, but I'd be interested in 0:06:12.360 --> 0:06:13.560 finding out why. 0:06:14.040 --> 0:06:16.480 All right, that was that was pretty good. Most people 0:06:16.920 --> 0:06:19.040 weren't surprised when you said gravity's weak. 0:06:19.960 --> 0:06:22.040 I don't know. I feel like if all the questions 0:06:22.080 --> 0:06:24.400 I've asked people, this is the one that flumms them 0:06:24.400 --> 0:06:26.880 the most. You know, people were like, what, I have 0:06:27.000 --> 0:06:30.960 no idea, or they had crazy ideas why gravity must 0:06:31.000 --> 0:06:33.719 be weak. I feel like usually we get one person 0:06:33.760 --> 0:06:35.600 who knows what the answer is or has a good 0:06:35.640 --> 0:06:38.240 clue about what's going on. This time, I feel like 0:06:38.320 --> 0:06:40.720 almost everybody was pretty clueless. I mean, one person said 0:06:40.880 --> 0:06:43.520 I always thought gravity was pretty strong, right, which kind 0:06:43.520 --> 0:06:47.520 of sums up the situation, right. Gravity's omnipresent in our lives. 0:06:47.520 --> 0:06:51.159 It dominates our experience, and yet it's so weak compared 0:06:51.200 --> 0:06:53.400 to the other really powerful forces we've discovered. 0:06:53.520 --> 0:06:55.800 Well, some people a couple of answers were that it 0:06:55.920 --> 0:06:59.440 had to do with distance, like gravity gets really weak 0:06:59.480 --> 0:07:00.000 with distance. 0:07:00.400 --> 0:07:02.120 That's right, And the problem there is that all the 0:07:02.160 --> 0:07:07.400 forces get weak with distance, like electromagnetism also falls as 0:07:07.440 --> 0:07:10.640 a distance grows. Right, So all of these forces follow 0:07:10.720 --> 0:07:12.960 this one over r squared rule or are as your 0:07:13.040 --> 0:07:15.640 distance from the thing that's giving. 0:07:15.360 --> 0:07:17.440 You the force, right, maybe maybe right? 0:07:18.000 --> 0:07:21.720 Maybe yeah, mostly we think, And so that can't be 0:07:21.760 --> 0:07:23.680 the answer, right, because all the other forces have that 0:07:23.720 --> 0:07:24.240 same feature. 0:07:24.360 --> 0:07:25.800 So when you say it's the weak is it's not 0:07:25.920 --> 0:07:29.880 that it changes over distances differently than the other forces. 0:07:29.600 --> 0:07:31.760 That's right. So maybe we should talk about what the 0:07:31.800 --> 0:07:35.200 forces are and compare them to each other so folks 0:07:35.240 --> 0:07:38.160 can get an understanding of how crazy weak gravity is. 0:07:38.360 --> 0:07:42.000 Right. So, Daniel, what are the forces of nature besides 0:07:42.040 --> 0:07:44.440 a bad movie with Ben Affleck than Center Bullet. 0:07:45.960 --> 0:07:48.960 Well, I think comedy. Comedy is definitely a force of nature. 0:07:49.680 --> 0:07:52.440 You know, it solves big problems around the world. Now, 0:07:52.960 --> 0:07:56.600 the fundamental forces are electromagnetism, right, that's the one that 0:07:56.680 --> 0:08:00.360 controls electricity and magnetism obviously, and his responsible for the 0:08:00.400 --> 0:08:04.800 cool things like light and lightning and all that cool stuff. 0:08:05.680 --> 0:08:08.800 And then there's the weak nuclear force, which is a 0:08:08.840 --> 0:08:12.280 force which is responsible for radioactive decay of a nuclei, right, 0:08:12.320 --> 0:08:15.120 And the cool thing about electricity and magnetism and the 0:08:15.120 --> 0:08:17.800 weak nuclear force. Is that we actually have shown that 0:08:17.800 --> 0:08:20.600 there are two sides of the same coin. As a 0:08:20.640 --> 0:08:23.080 particle physicist, we refer to them as one force. We 0:08:23.120 --> 0:08:26.880 call it the electro week. So sort of magnetism lost 0:08:26.880 --> 0:08:29.200 out there in the name merger, right, it should be 0:08:29.240 --> 0:08:32.920 electromagnetic week. But nobody voted to keep magnetism in the 0:08:33.000 --> 0:08:34.920 sort of the name of the partners in a law firm. 0:08:35.160 --> 0:08:38.000 Nobody lobbied for weak electro. 0:08:38.040 --> 0:08:44.440 Or magneto weak force. Yeah, yeah, again, we are suffering 0:08:44.760 --> 0:08:47.240 the fate of some anonymous committee of scientists that get 0:08:47.240 --> 0:08:49.200 to name these things. Right, Who are these people? 0:08:49.400 --> 0:08:52.679 Probably some grad student, right or some you know, like 0:08:52.720 --> 0:08:55.040 this is really weird, we'll call it this. 0:08:55.559 --> 0:08:58.520 Yeah. So we have electricity and magnetism, which is a 0:08:58.520 --> 0:09:00.640 single force. We have the weak nuclear force, which is 0:09:00.679 --> 0:09:03.760 really should be combined with electricity magnetism. And then there's 0:09:03.760 --> 0:09:05.840 the strong nuclear force. And this is the one that 0:09:05.920 --> 0:09:08.480 holds the nucleus together. You know, the nucleus is of 0:09:08.559 --> 0:09:12.480 just a bunch of positively charged protons and neutral neutrons. Right, 0:09:12.720 --> 0:09:15.840 it says only positively charged particles in the nucleus. So 0:09:15.880 --> 0:09:18.520 you might think, what it even holds the nucleus together. Right, 0:09:18.520 --> 0:09:22.000 you have all this positively charged stuff should be repelling themselves. Well, 0:09:22.040 --> 0:09:24.719 it's the strong nuclear force, and it does so by 0:09:24.720 --> 0:09:28.520 exchanging these crazy little particles we call gluons, and that 0:09:28.640 --> 0:09:31.200 holds the nucleus together, and it's pretty strong. It's even 0:09:31.240 --> 0:09:32.640 stronger than electromagnetism. 0:09:32.800 --> 0:09:35.280 Well, let's take a step back. So in the universe 0:09:35.320 --> 0:09:35.960 there's stuff. 0:09:36.720 --> 0:09:40.960 There's like, yes, firm that there is stuff in the universe. Yes, 0:09:41.440 --> 0:09:43.040 without reservation, there is stuff. 0:09:43.040 --> 0:09:46.199 I'm glad we saw that question. But I mean it's 0:09:46.200 --> 0:09:49.200 like there's stuff that has substance to it, that has 0:09:49.440 --> 0:09:52.040 mass to it, or you know that it sort of exists. 0:09:52.040 --> 0:09:55.840 And then there's also besides that, how these things interact 0:09:55.880 --> 0:09:57.680 with each other, like how they affect each other. 0:09:57.880 --> 0:10:00.800 That's right. There's the matter and then there's the forces. Right, 0:10:00.920 --> 0:10:02.800 the forces affect how they interact with each other. 0:10:02.840 --> 0:10:05.480 And that's pretty much the universe. That's like, it's matter 0:10:05.559 --> 0:10:06.120 and forces. 0:10:07.080 --> 0:10:08.760 Yeah, one way to look at the universe is that 0:10:08.800 --> 0:10:11.960 it's particles, right, or you would say matter and their forces. 0:10:12.400 --> 0:10:15.120 In modern particle physics, we think about one level deeper, 0:10:15.120 --> 0:10:18.240 which is we think of quantum fields and quantum fields 0:10:18.240 --> 0:10:21.320 are responsible both for matter and for forces. So we 0:10:21.320 --> 0:10:23.760 can talk about that maybe in another podcast. What is 0:10:23.760 --> 0:10:26.120 a quantum field? And how can I get one? You know, 0:10:26.160 --> 0:10:28.760 for lease or rent? What can they do for me? 0:10:29.040 --> 0:10:31.079 But yeah, I think it's fair still to think about 0:10:31.320 --> 0:10:33.839 the universe in terms of particles and forces. 0:10:34.400 --> 0:10:36.880 On that note, let's take a quick break. 0:10:41.160 --> 0:10:44.120 With big wireless providers. 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Visit 0:14:51.440 --> 0:14:54.240 usdairy dot com slash sustainability to learn more. 0:15:02.800 --> 0:15:04.640 There are only four kinds of forces. 0:15:04.960 --> 0:15:08.320 Yeah, there are four kinds of forces. So electromagnetism, weak 0:15:08.400 --> 0:15:12.240 nuclear force, strong nuclear force, and then of course gravity. Right, 0:15:12.280 --> 0:15:14.000 that's the fourth force that we've discovered. 0:15:14.240 --> 0:15:14.480 Okay. 0:15:14.840 --> 0:15:19.440 The fascinating thing is that different particles feel different forces, right, Like, 0:15:19.520 --> 0:15:22.040 some particles feel this set of forces. Some particles feel 0:15:22.040 --> 0:15:25.800 those set of force for example, right, particles with electric 0:15:25.920 --> 0:15:30.840 charge feel electromagnetism. Right. The electron, for example, is negatively charged, 0:15:31.080 --> 0:15:34.400 the proton is positively charged. You bring them close together, 0:15:34.600 --> 0:15:36.880 they're gonna pull on each other. They're gonna stuck each 0:15:36.880 --> 0:15:39.400 other together, right, because they have opposite charges. We all 0:15:39.400 --> 0:15:43.160 know that, but you bring a neutral particle nearby, it 0:15:43.280 --> 0:15:46.320 just totally ignores it, right, It doesn't feel it at all. Right, Right, 0:15:46.360 --> 0:15:49.160 It's like it's like somebody's walking through a crowd of 0:15:49.200 --> 0:15:51.520 people shouting, but they have headphones on so they can't 0:15:51.520 --> 0:15:53.880 hear anything. They're totally oblivious to it. 0:15:53.880 --> 0:15:55.360 It's kind of like how we talked about in a 0:15:55.360 --> 0:16:00.000 previous podcast. They're almost like languages or like social media platforms. 0:16:00.160 --> 0:16:02.800 Like some people are on Twitter, some people are on Facebook, 0:16:02.840 --> 0:16:04.920 but some people are not on this. And so if somebody, 0:16:05.160 --> 0:16:07.000 if you're not on Twitter and somebody sends you a tweet, 0:16:07.040 --> 0:16:08.880 you're not going to get it. And so it's just 0:16:08.920 --> 0:16:10.800 different ways that particles interact. 0:16:10.840 --> 0:16:14.440 That's right. Gravity is the Google plus social media, right 0:16:14.480 --> 0:16:21.480 because nobody uses the trends. It's ancient but powerless. Yeah, 0:16:21.520 --> 0:16:24.280 And so different particles feel different forces. And for example, 0:16:24.280 --> 0:16:27.720 an electron, while it feels electromagnetism because it has a 0:16:27.760 --> 0:16:30.840 negative charge, it doesn't feel the strong force at all. 0:16:31.200 --> 0:16:33.360 It will pass right by a bunch of particles that 0:16:33.360 --> 0:16:35.520 are really tugging on each other with a strong force 0:16:35.760 --> 0:16:39.280 and not be affected at all. Whereas quarks. Quarks feel 0:16:39.360 --> 0:16:42.480 all the forces. They feel a strong force, which is 0:16:42.480 --> 0:16:44.840 how they get pulled together in the nucleus. Remember, protons 0:16:44.880 --> 0:16:48.280 and neutrons are made of quarks. Quarks feel electromagnetism because 0:16:48.280 --> 0:16:51.080 they have electric charge, they feel the weak force. They 0:16:51.120 --> 0:16:53.280 also feel gravity, of course, because they have masks. So 0:16:53.640 --> 0:16:55.800 quarks get their fingers in everything. 0:16:56.360 --> 0:16:59.800 They get the feels for everything, They feel everything erect. 0:17:00.080 --> 0:17:03.840 They got the strong feels. Of course, they're really deeply 0:17:03.880 --> 0:17:07.520 emotional part of that. And on the other side of 0:17:07.520 --> 0:17:10.120 the spectrum, you've got things like neutrinos and trinos don't 0:17:10.160 --> 0:17:14.199 have electric charge, so they ignore all electricity and magnetism. Right, 0:17:14.240 --> 0:17:17.480 they don't interact with light. They're invisible. They pass right 0:17:17.520 --> 0:17:21.720 through anything that They ignore electromagnetic bonds, so they pass 0:17:21.760 --> 0:17:25.240 through most materials. They don't feel the strong force. The 0:17:25.280 --> 0:17:27.320 only way they interact is with the weak force. And 0:17:27.359 --> 0:17:29.960 the weak force is pretty weak, which is why neutrinos 0:17:29.960 --> 0:17:31.879 can mostly just pass through matter unaffected. 0:17:36.280 --> 0:17:39.000 So we have four fundamental forces, right, and gravity is 0:17:39.040 --> 0:17:40.800 one of these forces. And so when you say that 0:17:40.880 --> 0:17:44.560 gravity is weak, you actually mean it's weak compared to 0:17:44.640 --> 0:17:45.960 these other three forces. 0:17:46.240 --> 0:17:49.080 That's right. And so the ranking is the strong force 0:17:49.359 --> 0:17:53.200 is the strongest, right, so that one is actually well named. Congratulations, 0:17:53.640 --> 0:17:56.840 you know anonymous group of scientists. Yeah, we should be 0:17:56.840 --> 0:17:59.200 called the as of twenty eighteen, currently known to be 0:17:59.240 --> 0:18:04.880 the strongest force force. Right after that comes electromagnetism, and 0:18:05.040 --> 0:18:07.160 you know, we know that force's pretty powerful. You stick 0:18:07.160 --> 0:18:09.200 your finger in the socket, you're gonna feel the wrath 0:18:09.240 --> 0:18:12.160 of electromagnetism. Right, It's not an unfamiliar feeling. 0:18:12.240 --> 0:18:14.560 Right, try to stick your finger in anything, you feel it, right, 0:18:14.640 --> 0:18:18.360 because it's electromagnetism is the force that keeps you from 0:18:18.720 --> 0:18:23.680 basically passing through the table or passing through your car. 0:18:23.840 --> 0:18:27.880 Right, that's right, because electromagnetism is the basis of chemical bonds, right, 0:18:27.880 --> 0:18:29.879 and chemical bonds are really the thing that form the 0:18:29.920 --> 0:18:32.400 structure of your body. Right. You think of your body 0:18:32.440 --> 0:18:34.639 is like a bunch of particles, but it's held together 0:18:34.680 --> 0:18:37.280 by all these forces. It's like a chain link fence 0:18:37.560 --> 0:18:40.439 binding together these little particles that prevents you from passing 0:18:40.440 --> 0:18:43.720 through something else. Yeah, So we got the strong force, 0:18:43.840 --> 0:18:47.560 and then electromagnetism and then actually the weak nuclear force. Right, 0:18:47.600 --> 0:18:50.520 this is the force that like powers neutrinos and radioactive decay. 0:18:50.720 --> 0:18:55.000 It's much weaker than electromagnetism and much weaker than the 0:18:55.040 --> 0:18:55.680 strong force. 0:18:56.080 --> 0:18:58.240 Even weaker than the weak is gravity. 0:18:58.359 --> 0:19:01.919 That's right. If you make a list like strong force, electromagnetism, 0:19:01.960 --> 0:19:04.000 in the weak force, then you should leave like one 0:19:04.080 --> 0:19:07.760 hundred blank pages, and then you get to gravity. Because 0:19:07.800 --> 0:19:10.120 when we compare these forces, we put things like an 0:19:10.160 --> 0:19:13.200 equal distance apart, and we compare the strength of the forces. 0:19:13.440 --> 0:19:17.960 Gravity is ten to the thirty six times weaker than 0:19:18.000 --> 0:19:21.960 the weak force. That's ten with thirty six zeros in 0:19:21.960 --> 0:19:22.480 front of it. 0:19:22.640 --> 0:19:26.280 But isn't that sort of a matter of units or scale? 0:19:26.359 --> 0:19:28.760 Do you know what I mean? Like, it's much weaker, 0:19:28.800 --> 0:19:32.399 but only if you compare apples to apples, right, or 0:19:32.520 --> 0:19:33.040 just oranges. 0:19:33.119 --> 0:19:35.359 That's right, But put two protons next to each other, right, 0:19:35.680 --> 0:19:38.320 h Two protons have a certain amount of mass and 0:19:38.359 --> 0:19:40.920 a certain amount of electric charge, and the force of 0:19:40.960 --> 0:19:43.520 their charges is going to be much much stronger than 0:19:43.560 --> 0:19:44.679 the force from their masses. 0:19:44.760 --> 0:19:45.240 Oh I see. 0:19:45.280 --> 0:19:48.040 So yeah, if everything was much much more massive, then 0:19:48.080 --> 0:19:50.560 there would be stronger gravity. But you can compare these 0:19:50.600 --> 0:19:52.560 things apples to apples by comparing them at you know 0:19:52.600 --> 0:19:55.480 the same distance and the same basic unit of interaction. 0:19:55.760 --> 0:19:57.240 Right, But what if you take an apple put it 0:19:57.320 --> 0:19:58.200 next to another apple? 0:19:59.200 --> 0:20:01.280 Well, I think you can do that experiment. Nothing's going 0:20:01.359 --> 0:20:03.640 to happen because gravity is so weak. Right. You don't 0:20:03.680 --> 0:20:06.280 see two apples like pulling themselves together on the counter, right, 0:20:06.359 --> 0:20:09.679 And though built in apple collider, you know the apples 0:20:09.680 --> 0:20:12.200 are not drawn to each other. Gravity is a super 0:20:12.240 --> 0:20:14.280 weak force, and you can see this yourself. Right, you 0:20:14.840 --> 0:20:18.520 can do an experiment where you counter the entire gravitational 0:20:18.560 --> 0:20:21.680 force of an enormous celestial body like the Earth. Right, 0:20:22.240 --> 0:20:25.240