字幕表 動画を再生する 英語字幕をプリント I was going to talk about a thing called the Brunt device Cylon frequency. You know, the first thing to say about it is one of the reason why I wanted to talk about it is he actually has a symbol. So getting back to 60 symbols roots. For some reason, this particular frequency is always given the symbol capital in. And actually, I've tried very hard to find out why. It's called Capital, and I can't find anyone who would explain why it's called capital in. It's just every textbook you find it in. It's always called capital in. You'll find out in the comments, probably what, actually is it so actually, what got me to thinking about this is Just the other day I was thinking, I knew you were coming to do some filming. I think, What can I talk about it? I was just glancing up at the sky. It was one of those days where the clouds were in lines. You sometimes see very neatly arrayed lines of clouds on. I realize that actually is a really nice simple piece of physics, which explain why you sometimes get the clouds in lines like that. You find it, particularly if there's a mountain downstream from the mountain. If you got air blowing over the mountain, you'll find these lines of clouds. So what's actually happening is so we need to back up a little bit and do a little bit of physics, which is about buoyancy. So I got a balloon, Ah, helium filled balloon. Of course, it rises because it's less dense than the air around it. Actually, the less then something is the faster it rises. And obviously it's denser than air. It'll sink. And if you got it exactly right, it's exactly the same. Average density of the air around it will just float wherever you put it. And if you move, you got up. It'll stay there, and if you move it down, it'll stay there. That's a thing called neutral buoyancy that the thing just basically stays wherever you put it. And that that's what will happen if you got kind of a uniformed density atmosphere that you can take something. If it's floating there, you move it up. It's still floating. If, on the other hand, you got a stratified atmosphere, so actually slay the density decreases as you go up as the Earth's atmosphere does. Then what will happen this? You've got something which is neutrally buoyant. At this point, let's get rid of the balloon. Let's just have a little blob of air if you were to displace it upwards. Suddenly it's surrounded by air. There's less dense than it is, and so it'll sink again and it'll keep sinking. It'll actually sink for its original point, and then it will find itself in a region where it's less dense than the stuff around it, and now it will start to rise. And so it'll actually also late, backwards and forwards on the frequency at which it oscillates backwards and forwards. It is this thing called the brunt of Isola frequency, and the reason why that has to do with these lines of clouds is that if you have some air with some moisture in it, if it starts into going these oscillations, then as it rises it'll cool, and suddenly it will call to the point where clouds convince so you actually make clouds. And then when it sinks again, those clouds will then evaporate again and the clouds will disappear. So if you've got a Rh which is traveling along and undergoing these oscillations. You'll get clouds than the clouds will disappear in. The clouds will appear again in the clouds disappear again in the atmosphere. The period of this oscillation is something. It's a border 100 seconds. Typically, if you look at the house, the atmosphere stratified and use all the physical parameters. It works out about 100 seconds, and typically air is traveling at maybe 10 meters per second, normal kind of wind speed. So any consolation it will have traveled about a 10 meters per second. Over 100 seconds. You travel a kilometer, and that's why the scale of these clouds is typically a kilometer or so that you'll get cloud, then a gap, then a cloud. And this typical spacing between them is of order a kilometer. So it's just depositing a little cloud at the top of its way. It's actually well, they're the same air will form the cloud, and then the cloud will disappear again. So you basically create the cloud, and then the cloud disappears in the cloud appeared, so you're sort sort of seeing those high peaks. When it goes up, it forms the cloud. It's wherever you're at the top, you get the cloud and then it disappears again and then reappears again. I want that on selection. Fade away when it eventually stop oscillating and just sort of stopped like like a like a pendulum. If you just look at the mass, you actually figure out what the mass of this oscillation is. It really is. I think this thing called the harmonic oscillator on the harmonic oscillator will just keep oscillating forever. Now, obviously, there are other effects going on as well. So they're all will be damping terms, which means that actually, one of these waves won't actually last forever. But it really can persist for many, many oscillations. Actually, you can have this whole series of clouds being created in that way. So this frequency comes up all over the place so it comes up in oceans because you have exactly the same effect. In oceans of pockets of water rising and falling in stars, you can have a little bits of the star in the stellar atmosphere rising and falling on Daryl dipped, driven by the same frequency. This front Faisal the frequency three other side of the solar system on the game. Something here again. You can see the net pull of the earth and the sun is all nicely lined up, which will keep it in an orbit basically following following the Earth around. They used to be lots of science fiction stories about l three used to be a popular place to put the anti Earth. Or, you know, if you're an evil genius, that's where you put your hidden layer.