WEBVTT - How Weather Works 0:00:04.440 --> 0:00:12.000 Text with technology with tech Stuff from stuff works dot com. 0:00:12.000 --> 0:00:14.600 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.880 --> 0:00:18.560 Jonathan Strickland. I'm a senior writer here with how stuff 0:00:18.600 --> 0:00:22.720 works dot com, and today I wanted to talk about 0:00:22.760 --> 0:00:25.560 something I got to do. Those pretty cool just last week, 0:00:26.200 --> 0:00:28.480 well last week as of the time I'm recording this, 0:00:29.280 --> 0:00:32.839 I got to go visit the Weather Company to do 0:00:33.000 --> 0:00:37.960 some interviews about meteorology and also ibm s Watson platform. 0:00:38.000 --> 0:00:40.400 And it was a really cool experience to actually get 0:00:40.440 --> 0:00:43.880 to walk around and see the various people who work 0:00:44.080 --> 0:00:48.199 on weather science and try to figure out what was 0:00:48.240 --> 0:00:50.040 the weather doing right now and was it going to 0:00:50.080 --> 0:00:54.160 do next. I even managed to cause some problems for 0:00:54.200 --> 0:00:58.840 the Weather Channel, but that wasn't entirely my fault. Uh 0:00:58.960 --> 0:01:01.480 Now to explain us, the Weather Channel and the Weather 0:01:01.520 --> 0:01:05.320 Company used to be the same entity, but then IBM 0:01:05.360 --> 0:01:10.679 acquired the product and technology divisions of the Weather Company 0:01:10.720 --> 0:01:13.360 and they bought those sections, but they didn't buy the 0:01:13.400 --> 0:01:18.560 television broadcast business. So now they are two independent businesses. 0:01:18.600 --> 0:01:20.840 One of them is run by IBM, the other one 0:01:20.920 --> 0:01:25.920 is its own standalone weather broadcast service. That being said, 0:01:25.920 --> 0:01:29.360 they still work very closely together. The Weather Channel still 0:01:29.400 --> 0:01:32.679 gets a lot of its data and it's information from uh, 0:01:32.840 --> 0:01:36.160 the Weather Company, so it's not like they are completely 0:01:37.080 --> 0:01:39.480 independent of each other, and they both still exist in 0:01:39.520 --> 0:01:42.360 the same building. They both are located out of the 0:01:42.400 --> 0:01:46.440 same headquarters building here in Atlanta, Georgia. So there is 0:01:46.760 --> 0:01:51.600 a Weather Channel studio that is in part of this building, 0:01:52.120 --> 0:01:55.920 and there's the Weather Company offices that's on different floors 0:01:55.920 --> 0:01:59.800 of the building, and UH they kind of co occupy 0:02:00.120 --> 0:02:04.560 space even though they are no longer corporately speaking anyway 0:02:04.760 --> 0:02:07.840 the same entity. So I thought it'd be fun to 0:02:07.880 --> 0:02:11.519 do an episode about meteorology and weather models. This is 0:02:11.560 --> 0:02:14.880 gonna be a two part episode because I have to 0:02:14.919 --> 0:02:18.800 cover the science behind weather first and then talk about 0:02:18.960 --> 0:02:25.160 meteorology to let you understand how meteorologists base their forecasts 0:02:25.200 --> 0:02:28.400 off of weather conditions. You have to understand the complexities 0:02:28.440 --> 0:02:32.160 of whether before you can really get a grip on 0:02:32.240 --> 0:02:35.400 what it is that meteorologists do. And so in order 0:02:35.440 --> 0:02:37.560 to do that, this episode is gonna be a little 0:02:37.639 --> 0:02:41.360 less about tech and more about science in order for 0:02:41.440 --> 0:02:45.000 us to have a deeper understanding of meteorology. In the 0:02:45.040 --> 0:02:48.040 next episode, I should I should also mention We've covered 0:02:48.080 --> 0:02:52.240 this topic in Tangential Ways and Older Tech Stuff episodes, 0:02:52.680 --> 0:02:56.480 but it was more than overdue for a revisit. So 0:02:56.520 --> 0:03:00.200 that's why we're going to talk about it today. We're 0:03:00.200 --> 0:03:07.040 gonna really look at how weather systems actually work. Uh. 0:03:07.080 --> 0:03:09.120 And before I get too far, I guess I should 0:03:09.160 --> 0:03:12.280 actually explain what I meant when I said I caused 0:03:12.280 --> 0:03:15.480 some problems for the Weather Channel. So while I was 0:03:15.520 --> 0:03:18.920 at their headquarters, I was getting ready to shoot a 0:03:19.000 --> 0:03:22.840 video interview with a man named Dale Eck, who is 0:03:22.880 --> 0:03:27.360 the director of the Weather Forecast Center for the Weather Company. 0:03:27.440 --> 0:03:30.399 So this guy is the head meteorologist in charge. He's 0:03:30.400 --> 0:03:34.920 been doing work in meteorology for thirty years, and he 0:03:34.960 --> 0:03:38.000 has a desk that's very close to the broadcast studio 0:03:38.160 --> 0:03:41.840 for the Weather Channel. The broadcast studio has glass walls, 0:03:42.480 --> 0:03:45.200 so you can see right through the walls. If you 0:03:45.240 --> 0:03:47.960 ever watch a broadcast on the Weather Channel and they 0:03:47.960 --> 0:03:51.320 shoot from inside the studio, you'll see people walking in 0:03:51.360 --> 0:03:55.240 the background. You'll see desks and monitors and lots of 0:03:55.240 --> 0:03:57.840 of colorful imagery because people have got a lot of 0:03:57.880 --> 0:04:02.720 weather maps up in the background, so all of that's real. 0:04:03.000 --> 0:04:07.320 Those are the actual people who work at the company. Uh, 0:04:07.360 --> 0:04:09.400 and that's where we were shooting our videos. We were 0:04:09.400 --> 0:04:14.119 shooting off to one side of this studio, and while 0:04:14.160 --> 0:04:16.240 we're getting ready to shoot, we had set up the camera. 0:04:16.880 --> 0:04:19.960 I was miked. We had a shotgun mike so that 0:04:20.000 --> 0:04:25.600 we can pick up Mr X his his contributions. We 0:04:25.600 --> 0:04:28.520 were off to one side of the studio, so we're 0:04:28.600 --> 0:04:32.080 up against where the glass walls are, but we weren't 0:04:32.360 --> 0:04:36.360 directly across from where the cameras were set up. Um, 0:04:36.400 --> 0:04:39.320 they did have sets where they could pivot around where 0:04:39.320 --> 0:04:41.920 we would have essentially been in the background for those 0:04:42.040 --> 0:04:44.560 those shots if they had set something up, but they 0:04:44.600 --> 0:04:48.000 were mostly shooting directly against the back wall of the 0:04:48.080 --> 0:04:51.599 studio and we were on one of the sidewalls. So 0:04:51.640 --> 0:04:55.720 we're getting ready to shoot, and one of the the 0:04:55.800 --> 0:04:59.120 employees over at the Weather Company very helpfully pointed out 0:04:59.279 --> 0:05:04.039 a bank of light switches that were in control of 0:05:04.080 --> 0:05:08.120 production lights. So flipping those switches would turn several lights 0:05:08.279 --> 0:05:11.480 on in the area we were standing in That would 0:05:11.600 --> 0:05:14.480 end up providing a lot more light for our video, 0:05:14.720 --> 0:05:17.279 and that is really important if you're shooting video, you 0:05:17.320 --> 0:05:20.720 need good lighting. So after being told about them, we 0:05:20.880 --> 0:05:24.000 turned them on. We being my producer, turned them on, 0:05:24.800 --> 0:05:27.320 and you know, he was essentially told to do it, 0:05:27.400 --> 0:05:30.000 so that's what he did. And it didn't take very 0:05:30.040 --> 0:05:35.560 long before a floor manager for the Weather Channel, very 0:05:35.560 --> 0:05:37.840 calmly walked up and asked us to knock that off. 0:05:38.080 --> 0:05:42.000 Although I should say she was incredibly friendly and professional. 0:05:42.080 --> 0:05:45.600 She wasn't mean about it at all, but explained that 0:05:45.760 --> 0:05:48.880 the light that we had created was bleeding into the set. 0:05:49.000 --> 0:05:51.240 You know, it's a glass wall, lights just passing right 0:05:51.240 --> 0:05:55.479 through it, so it was affecting the shot for the 0:05:55.560 --> 0:06:02.600 actual Weather Channel, you know, the nationally televised Weather Channel broadcast. 0:06:03.839 --> 0:06:08.000 So my little YouTube video that I was shooting was 0:06:08.080 --> 0:06:14.919 impacting a nationally broadcast television scene. So that was a 0:06:14.960 --> 0:06:19.120 little bit of a Oopsie Daisy moment for me and 0:06:19.160 --> 0:06:22.480 my team. The nice thing is it was probably pretty 0:06:22.480 --> 0:06:24.600 subtle and it probably didn't have that big of an 0:06:24.600 --> 0:06:27.440 impact at all, but still it made us feel like 0:06:27.480 --> 0:06:31.120 we were kind of jerk faces. And if you were 0:06:31.920 --> 0:06:35.960 watching the Weather Channel last week or this would that 0:06:35.960 --> 0:06:39.920 would have been, um, you know, this is June right now, 0:06:40.000 --> 0:06:43.840 so it would have been June Thursday. If you were 0:06:43.839 --> 0:06:47.400 watching the Weather Channel, you know, trying to keep up 0:06:47.400 --> 0:06:51.200 to date with Tropical Storm Cindy, and you were wondering, 0:06:52.000 --> 0:06:56.560 why is the lighting going all crazy in this broadcast? 0:06:57.120 --> 0:07:01.920 That was us are bad, But I have to really 0:07:01.920 --> 0:07:04.480 thank everyone who works for the Weather Channel and the 0:07:04.480 --> 0:07:08.080 Weather Company. They were very generous with their time and 0:07:08.160 --> 0:07:12.360 they gave us lots of leeway to shoot really cool video. 0:07:12.520 --> 0:07:14.520 So it was a great visit and it helped me 0:07:14.520 --> 0:07:18.640 appreciate the complexities of meteorology on a deeper level. So 0:07:18.720 --> 0:07:24.960 let's now talk about weather forecasting. It's an interesting business. 0:07:25.680 --> 0:07:30.360 At a very very high level, like a super simplistic level. 0:07:31.320 --> 0:07:35.920 Weather forecasting, at least in the recent past, involved taking 0:07:36.040 --> 0:07:41.040 lots of observations, comparing those observations of present conditions to 0:07:41.440 --> 0:07:45.560 things that had happened before in the past, researching what 0:07:45.800 --> 0:07:49.760 followed those similar conditions when they did happen before, and 0:07:49.800 --> 0:07:51.880 then making a guess as to what is going to 0:07:51.920 --> 0:07:57.400 happen next based upon past experience. That's a drastic oversimplification, 0:07:57.440 --> 0:08:00.400 and really it's saying that it's about pattern recognition, and like, 0:08:01.040 --> 0:08:04.000 let's say, if you notice that when the temperature goes 0:08:04.160 --> 0:08:06.880 up at a certain time of day, with these other 0:08:06.960 --> 0:08:11.320 factors in place, the chance of rain increases drastically based 0:08:11.360 --> 0:08:15.160 upon past experience. You might use that to help forecast 0:08:15.160 --> 0:08:17.520 the weather and say there's a good chance that's going 0:08:17.560 --> 0:08:21.040 to rain later today because these other factors are at play, 0:08:21.360 --> 0:08:25.760 and other times when that has happened, it's rained. But 0:08:26.040 --> 0:08:30.440 let me give you a more simple example about how 0:08:30.480 --> 0:08:33.080 this might work out. Let's say you've got some basic 0:08:33.280 --> 0:08:39.240 meteorological gear, like some sensors, a barometer, wind speed, indicator, 0:08:39.320 --> 0:08:42.680 wind direction. You know how much humidity is in the air. 0:08:43.000 --> 0:08:45.400 You know the temperature because you've got a thermometer, all 0:08:45.400 --> 0:08:47.439 these sort of things. These are the typical sensors you 0:08:47.480 --> 0:08:53.000 would find at a weather observation point. You've kept a 0:08:53.040 --> 0:08:58.240 log book of weather for this particular location that goes 0:08:58.320 --> 0:09:01.559 back two decades, so you've got twenty years of information 0:09:01.720 --> 0:09:06.640 at your disposal, twenty years of collections of data points 0:09:06.720 --> 0:09:10.760 and what was actually happening with the weather. You make 0:09:10.760 --> 0:09:14.160 your observation in the morning, you note the temperature, the 0:09:14.200 --> 0:09:17.280 air pressure, You've got all these different factors, and then 0:09:17.320 --> 0:09:20.240 you look at your log books and you look for 0:09:20.360 --> 0:09:25.599 days that are similar to the conditions you are currently observing. 0:09:27.200 --> 0:09:30.079 Then you look to see what happened later on those 0:09:30.120 --> 0:09:34.320 previous days. So if you had one hundred mornings that 0:09:34.360 --> 0:09:37.600 are similar to the conditions of the morning you are 0:09:38.160 --> 0:09:40.800 concerned with, like this morning, you wake up, this morning, 0:09:41.080 --> 0:09:44.240 you take readings, you find one other, one other examples 0:09:44.240 --> 0:09:47.640 in your log book that are similar to today, and 0:09:47.640 --> 0:09:50.559 then you notice that on seventy of those one days 0:09:50.600 --> 0:09:53.800 it rained. You could say there's a seventy chance of rain. 0:09:54.679 --> 0:09:58.520 That seventy of the time, when conditions were the way 0:09:58.559 --> 0:10:04.120 they are right now, it rained. Of those days where 0:10:04.120 --> 0:10:06.280 the conditions were exactly the way they are right now, 0:10:06.760 --> 0:10:10.199 it did not rain. And I don't really mean exactly. 0:10:10.400 --> 0:10:13.440 I guess I should say approximately, because weather is incredibly 0:10:13.480 --> 0:10:18.000 complicated and to have two weather systems behave exactly the 0:10:18.080 --> 0:10:25.520 same way under the same circumstances is pretty unlikely. But this, 0:10:25.679 --> 0:10:30.800 again is a drastic oversimplification of how weather forecasts work. 0:10:30.840 --> 0:10:34.560 It does give you a basic idea of the the 0:10:34.720 --> 0:10:39.840 principle behind meteorological forecasts, at least until more recently we 0:10:39.920 --> 0:10:45.040 get into weather simulation and huge amounts of data processing. 0:10:45.080 --> 0:10:48.560 Today that gets a lot more sophisticated than just what 0:10:48.640 --> 0:10:52.000 are the conditions today and what happened on previous occasions 0:10:52.000 --> 0:10:56.920 when those conditions were present. But keep in mind meteorology 0:10:57.280 --> 0:11:02.920 is constantly evolving. It has ever reached a perfect level status, 0:11:02.960 --> 0:11:06.400 as anyone who has depended upon a weather forecast knows, 0:11:06.960 --> 0:11:09.920 you've probably in the past looked at a weather forecast 0:11:09.960 --> 0:11:11.839 and said, oh, there's no chance of rain, and then 0:11:12.000 --> 0:11:15.560 a thunderstorm pops up. Well, that's because weather is really 0:11:15.600 --> 0:11:20.600 complicated and sometimes a hyper local event can occur that 0:11:20.840 --> 0:11:24.880 is impossible to really predict when you're looking at, say 0:11:25.040 --> 0:11:29.240 a regional weather forecast, because your fidelity doesn't get that small. 0:11:29.320 --> 0:11:33.240 You can't predict everything that happens within that region with 0:11:33.320 --> 0:11:37.080 perfect accuracy. You're giving more of an overall look for 0:11:37.200 --> 0:11:41.800 the region as a whole. So it gets really complex. 0:11:42.360 --> 0:11:45.000 There are a lot of different variables, and there's a 0:11:45.000 --> 0:11:49.520 lot of different technology that goes into gathering the information 0:11:49.559 --> 0:11:53.200 about those variables and then crunching those numbers to make 0:11:53.280 --> 0:11:55.520 some meaning out of it, which is why it's an 0:11:55.600 --> 0:12:00.680 ideal topic or text stuff. Now, if we are to 0:12:00.760 --> 0:12:05.680 understand really how meteorology works, we've we've got to take 0:12:05.720 --> 0:12:07.760 a deep looking at a look at whether or not 0:12:07.800 --> 0:12:10.080 a deep looking that makes no sense, but a deep 0:12:10.120 --> 0:12:13.439 look at whether. We at least need to get as 0:12:13.480 --> 0:12:16.400 deep in understanding for whether as we can in a 0:12:16.480 --> 0:12:19.440 casual podcast setting. So the first step is acknowledging the 0:12:19.440 --> 0:12:23.360 difference between weather and climate. This is important because I 0:12:23.400 --> 0:12:28.400 see these two concepts conflated all the time, and frequently 0:12:28.440 --> 0:12:31.880 it pops up in in political discussions because you have 0:12:31.920 --> 0:12:38.520 people with agendas who want to push specific action items 0:12:38.559 --> 0:12:42.360 that favor their philosophy over the action items of people 0:12:42.400 --> 0:12:47.480 who oppose their philosophy. And frequently in those discussions, people 0:12:47.520 --> 0:12:51.600 will start to make generalizations about weather and climate that are, 0:12:53.280 --> 0:12:58.280 if not untrue, at least inaccurate. So let's settle that. 0:12:58.400 --> 0:13:01.600 And I know all of you know this, but it's 0:13:01.600 --> 0:13:07.520 good to at least start with the baseline. So whether 0:13:07.679 --> 0:13:11.800 refers to the current state of the atmosphere, it's it's timely. 0:13:11.920 --> 0:13:14.840 It's either something that's happening right now, like you're talking 0:13:14.840 --> 0:13:17.760 about the weather right now, you're talking about a weather forecast. 0:13:17.880 --> 0:13:19.920 You're talking about something that's going to happen within the 0:13:19.960 --> 0:13:23.920 next day to ten days maybe or maybe a little 0:13:23.960 --> 0:13:26.439 further out, but that's about it. Or you're talking about 0:13:26.480 --> 0:13:29.720 what has happened over the past few days, but that's 0:13:29.760 --> 0:13:32.559 about it. Like it's about a month or so of 0:13:32.600 --> 0:13:38.520 time stretching backward and forward uh in total from where 0:13:38.559 --> 0:13:41.720 you are right now, So it's very timely. Climate, however, 0:13:42.320 --> 0:13:46.360 is about whether patterns over vast spans of time or 0:13:46.400 --> 0:13:50.280 at least several years, if not decades of time. So 0:13:50.400 --> 0:13:55.320 climate is more about general weather patterns and how they 0:13:55.360 --> 0:14:01.439 behave over these these uh the span of years. So 0:14:01.559 --> 0:14:05.640 climate change is very gradual. That means that you're not 0:14:05.760 --> 0:14:09.360 likely to notice climate change on a day to day basis, 0:14:09.559 --> 0:14:13.240 which means that if you use an argument like global 0:14:13.240 --> 0:14:18.280 warming isn't real because it's snowed last winter, that's a 0:14:18.280 --> 0:14:23.520 fallacious argument because you're talking there about whether not climate 0:14:24.320 --> 0:14:27.640 climate would be a gradual change, which over the course 0:14:27.680 --> 0:14:30.480 of several years might mean that after several years it's 0:14:30.520 --> 0:14:33.680 snowing less and less, or the snow is not lasting 0:14:33.760 --> 0:14:37.720 very long, the the period of time where it does 0:14:37.800 --> 0:14:41.600 snow is decreasing, like it's becoming more concentrated in a 0:14:41.720 --> 0:14:44.920 narrower span of days. Those are the sort of things 0:14:44.920 --> 0:14:47.680 we might see as a result of climate change over 0:14:47.720 --> 0:14:52.080 the course of several years. But we humans aren't very 0:14:52.080 --> 0:14:55.480 good at conceptualizing that. We tend to focus on stuff 0:14:55.520 --> 0:14:59.360 that we've recently observed, but particularly when it's something that's 0:14:59.360 --> 0:15:02.440 happening at at times. So if you were to have 0:15:02.640 --> 0:15:07.120 an unusually mild summer, you might think, well, that says 0:15:07.200 --> 0:15:11.920 that climate change is is bogus because I should it 0:15:11.960 --> 0:15:15.680 should be much hotter than that. That's not taking into 0:15:15.720 --> 0:15:21.800 account the long term changes in trends. So again, climate 0:15:21.960 --> 0:15:25.840 is the long view, whether is what is happening right now? 0:15:26.840 --> 0:15:30.400 Now that we've established that, we can get past those 0:15:31.280 --> 0:15:36.560 weird straw man arguments people make that tried to discredit 0:15:36.600 --> 0:15:41.000 one another for whatever philosophy they have using weather in 0:15:41.080 --> 0:15:44.600 place of climate, it just doesn't work. Climate change, by 0:15:44.600 --> 0:15:48.240 the way, is a real thing. Uh, it is a 0:15:48.320 --> 0:15:51.160 scientific consensus has found that climate change is real and 0:15:51.160 --> 0:15:54.400 that humans have had an impact, a significant impact on 0:15:54.520 --> 0:15:59.080 climate change. And consensus is no small matter getting scientists 0:15:59.080 --> 0:16:02.040 to agree to some thing. That's I mean, science is 0:16:02.080 --> 0:16:05.360 all about questioning claims and putting them to the test. 0:16:05.440 --> 0:16:08.880 That's how science works is you make an observation or 0:16:08.920 --> 0:16:11.920 you make a prediction, and then you test it over 0:16:11.960 --> 0:16:14.040 and over and over again to see if it holds true. 0:16:14.240 --> 0:16:16.600 If you get to a scientific consensus where a lot 0:16:16.600 --> 0:16:20.040 of scientists, the vast majority of them all agree on something, 0:16:20.440 --> 0:16:24.800 that's a powerful statement, although we often will see that dismissed. 0:16:25.360 --> 0:16:27.920 Uh So, again, this isn't to get political. This is 0:16:27.960 --> 0:16:33.640 just stating a scientific fact, not a political effect. Climate 0:16:33.680 --> 0:16:36.960 change is real, humans have an impact on it. What 0:16:37.040 --> 0:16:39.720 does that mean politically, Well, that's a totally different discussion. 0:16:41.280 --> 0:16:46.640 So there's probably people out there who wish that climate 0:16:46.720 --> 0:16:48.800 change wasn't a real thing, that this was all just 0:16:48.880 --> 0:16:53.120 a manufactured story. But if wishes were horses, beggars would ride. 0:16:53.560 --> 0:16:56.520 As my old social studies teacher would say, So, climate 0:16:56.560 --> 0:16:59.480 describes weather trends over many, many years, and weather describes 0:16:59.560 --> 0:17:03.000 changing atmospheric conditions on a much shorter time span. And 0:17:03.040 --> 0:17:08.040 our atmosphere is where weather happens. Again, not a big shock. 0:17:08.160 --> 0:17:11.760 This is elementary school science. It's made up of a 0:17:11.760 --> 0:17:15.560 lot of gases our atmosphere. The big one, of course, 0:17:15.640 --> 0:17:19.679 is nitrogen, that makes up about of the atmosphere. Then 0:17:19.800 --> 0:17:23.760 comes oxygen, which is my personal favorite. I'm totally breathless 0:17:23.880 --> 0:17:28.600 without oxygen. It makes up about of the art's atmosphere, 0:17:28.760 --> 0:17:31.960 and then you've got less than a percent of argone 0:17:32.440 --> 0:17:36.080 point zero three carbon dioxide, and the rest of it 0:17:36.119 --> 0:17:42.119 is made up of small amounts of water, vapor, hydrogen, ozone, neon, helium, crypton, 0:17:42.280 --> 0:17:47.399 and xenon. Our atmosphere is pretty thick, and there's not 0:17:47.480 --> 0:17:51.560 really a hard barrier between the top of the atmosphere 0:17:51.600 --> 0:17:55.920 in the beginning of space. It's kind of a fuzzy barrier, 0:17:56.240 --> 0:17:58.840 and there's not like you can't point to a specific 0:17:58.920 --> 0:18:03.080 height above the Earth and say, specifically, at this point 0:18:03.080 --> 0:18:06.520 the atmosphere ends, and this is just empty space beyond it. 0:18:07.119 --> 0:18:09.399 The best you can do is do an estimation. So 0:18:09.480 --> 0:18:12.639 generally speaking, the atmosphere pretty much peters out into nothing 0:18:13.240 --> 0:18:17.440 once you reach about six hundred miles or one thousand 0:18:17.520 --> 0:18:21.200 kilometers above sea level, So you gotta go at sea 0:18:21.280 --> 0:18:24.800 level six d miles up and you're pretty much at 0:18:24.800 --> 0:18:28.600 the point where you're not going to find any molecules 0:18:28.680 --> 0:18:33.639 of any significant number that represent an atmosphere. Gravity holds 0:18:33.720 --> 0:18:36.679 the gases down to the planet, which I'm sure seems 0:18:36.680 --> 0:18:40.480 pretty obvious. Without gravity, the atmosphere would dissipate into space, 0:18:40.520 --> 0:18:44.159 but don't worry, so would we. So the gases wouldn't 0:18:44.160 --> 0:18:47.080 be lonely for very long. It's a moot point because 0:18:47.119 --> 0:18:50.520 we do have gravity, so we're good. The atmosphere is 0:18:50.560 --> 0:18:55.320 also a very heavy thing. Collectively, if you take all 0:18:55.359 --> 0:19:00.320 of the other's atmosphere, it weighs five point five quadrillion uns. 0:19:01.000 --> 0:19:06.160 That's four point nine nine quadrillion metric tons. Again, that's collective. 0:19:06.200 --> 0:19:09.960 That's all the atmosphere that surrounds our planet. Obviously, you 0:19:10.000 --> 0:19:13.439 are not walking around with a few quadrillion tons of 0:19:13.480 --> 0:19:17.000 weight on top of you. This weight of the atmosphere 0:19:17.119 --> 0:19:22.560 creates atmospheric pressure. The pressure is different at various altitudes, 0:19:22.600 --> 0:19:25.400 which makes sense. If you are on top of a mountain, 0:19:25.920 --> 0:19:29.760 you actually have less atmosphere above you, like there's less 0:19:29.880 --> 0:19:32.760 air between you and outer space. If you're on top 0:19:32.800 --> 0:19:35.240 of a mountain, then if you were standing in the 0:19:35.240 --> 0:19:38.679 middle of a valley, there would be more air between 0:19:38.720 --> 0:19:42.120 you and outer space. Because again remember we're measuring that 0:19:42.280 --> 0:19:46.240 by sea level, so your altitude makes a big difference. 0:19:46.840 --> 0:19:50.360 You would have a lower atmospheric pressure at a high 0:19:50.400 --> 0:19:53.960 altitude than you would somewhere with a low altitude. The 0:19:54.000 --> 0:19:57.600 pressure also compresses the gases in the atmosphere, so air 0:19:57.720 --> 0:20:00.439 closer to the surface of the planet is more dense 0:20:00.720 --> 0:20:03.720 than air that's near the edges of space, and all 0:20:03.800 --> 0:20:07.280 the weight above that low altitude air is forcing the 0:20:07.359 --> 0:20:09.679 various molecules to get all chummy with each other. So 0:20:09.720 --> 0:20:14.640 you've got denser air closer to the surface. So I've 0:20:14.680 --> 0:20:17.359 got more to say about atmospheric pressure and it's rolling 0:20:17.440 --> 0:20:20.840 weather in just a minute. But before I jump into that, 0:20:21.000 --> 0:20:30.919 let me take a breath and thank our sponsor. All right, 0:20:30.960 --> 0:20:34.680 So let's say you are at sea level. The average 0:20:34.720 --> 0:20:38.400 atmospheric pressure at sea level is fourteen point seven pounds 0:20:38.560 --> 0:20:42.679 or six point seven kilograms per square inch. As you 0:20:42.720 --> 0:20:46.240 climb in altitude, the pressure and density of the air 0:20:46.280 --> 0:20:49.320 around you decreases until you reach a point where it 0:20:49.359 --> 0:20:52.520 would be quite difficult to breathe, and you need to 0:20:52.560 --> 0:20:56.280 breathe in more in order to get enough oxygen so 0:20:56.320 --> 0:21:01.400 that you can continue, you know, living. So you might 0:21:01.520 --> 0:21:03.800 take a lungfull and not get enough oxygen to remain 0:21:03.840 --> 0:21:06.159 conscious if you're at a high enough altitude, which is 0:21:06.280 --> 0:21:09.280 part of the reason why mountain climbers have to tackle 0:21:09.400 --> 0:21:13.240 really tall mountains and stages. They have to have camps 0:21:13.280 --> 0:21:16.320 where they take a break and acclimate to the lower 0:21:16.359 --> 0:21:21.320 air pressure and lower air density of higher altitudes. So 0:21:21.400 --> 0:21:24.160 gravity obviously plays a big part in weather systems keeping 0:21:24.200 --> 0:21:27.720 our atmosphere nice and in place. The Sun obviously also 0:21:27.800 --> 0:21:31.399 contributes to our weather patterns. The Sun is the direct 0:21:31.440 --> 0:21:34.400 source for most of the energy here on Earth. Some 0:21:34.520 --> 0:21:36.520 of the energy of the Sun gives off warms our 0:21:36.640 --> 0:21:41.800 atmosphere directly, but most atmospheric warming actually comes not from 0:21:41.880 --> 0:21:45.359 sunlight coming down to Earth, but rather the heat that 0:21:45.520 --> 0:21:49.120 is radiated off of Earth. The heat that the Earth 0:21:49.200 --> 0:21:53.280 has absorbed from the Sun. So the plant itself absorbs 0:21:53.320 --> 0:21:57.320 heat and then releases that heat later on. That tends 0:21:57.359 --> 0:22:00.560 to be what heats up most of the atmosphere. The 0:22:00.600 --> 0:22:03.359 reason this happens is because the type of radiation that 0:22:03.400 --> 0:22:06.520 we're talking about radiation from the Sun is short wave 0:22:06.800 --> 0:22:10.840 radiation that easily passes through the gases the atmosphere and 0:22:10.880 --> 0:22:13.840 then it gets absorbed by the planet. When the planet 0:22:13.920 --> 0:22:19.680 emits heat, it's emitting long wave radiation. Long wave radiation 0:22:19.720 --> 0:22:24.000 gets absorbed readily by the atmosphere, so the atmosphere warms 0:22:24.240 --> 0:22:28.000 from the ground up. And that also explains why if 0:22:28.080 --> 0:22:31.119 you were to climb a mountain as you would climb 0:22:31.119 --> 0:22:35.600 in elevation, the temperature would decrease to a point anyway 0:22:35.840 --> 0:22:40.880 in the troposphere. So there are four layers of Earth's atmosphere, 0:22:41.000 --> 0:22:45.960 and you classify those four layers by temperature ranges. The 0:22:46.040 --> 0:22:50.159 layers aren't uniform. Their thickness varies a bit as you 0:22:50.240 --> 0:22:53.920 go from region to region around the Earth, but they're 0:22:54.040 --> 0:23:00.520 roughly outer shells of Earth. The innermost one is the atmosphere, 0:23:00.800 --> 0:23:02.880 as the level closest to the surface of the Earth. 0:23:03.160 --> 0:23:07.480 It ends somewhere around seven miles or eleven kilometers above 0:23:07.560 --> 0:23:12.399 sea level on average. Throughout the troposphere, as you climb altitudes, 0:23:12.440 --> 0:23:16.119 the temperature drops. That's one of the markers for the 0:23:16.119 --> 0:23:20.040 troposphere that all stops when you pass the tropo pause. 0:23:20.320 --> 0:23:24.160 That is the boundary between the troposphere and the stratosphere. 0:23:24.200 --> 0:23:27.840 That is the next layer out from the troposphere. The 0:23:27.880 --> 0:23:31.440 tropospheres where all of Earth's weather happens. It also accounts 0:23:31.440 --> 0:23:35.240 for eighty percent of the air in our atmosphere. The 0:23:35.320 --> 0:23:39.200 other three layers contain the remaining twenty of the air 0:23:39.240 --> 0:23:44.040 in our atmosphere. Now, remember our atmosphere extends all the 0:23:44.080 --> 0:23:48.040 way up to six hundred miles above sea level, whereas 0:23:48.040 --> 0:23:53.040 the troposphere ends at seven miles above sea level. So 0:23:53.160 --> 0:23:56.760 within those first seven miles out of six hundred, you 0:23:56.800 --> 0:24:00.240 have eighty percent of the air in our atmosphere. That 0:24:00.320 --> 0:24:04.480 tells you how densely packed those gases are. The stratosphere 0:24:04.520 --> 0:24:08.440 extends from the tropopause up to about thirty miles above 0:24:08.480 --> 0:24:11.720 sea level or forty eight kilometers. For the first few miles, 0:24:11.960 --> 0:24:15.000 the temperature of the stratosphere remains pretty stable with regards 0:24:15.000 --> 0:24:18.560 to the tropopause below. So remember you climb up through 0:24:18.600 --> 0:24:21.600 the troposphere, the temperature starts to go down. When you 0:24:21.680 --> 0:24:24.840 hit the tropopause, the temperature pretty much stabilizes, and then 0:24:24.840 --> 0:24:27.480 you're in the stratosphere and the temperature remains stable for 0:24:27.520 --> 0:24:31.920 the first several miles, but then the temperatures actually start 0:24:31.960 --> 0:24:35.640 to increase. It starts to get warmer as you move 0:24:35.680 --> 0:24:39.320 through the stratosphere. This is because at those upper levels 0:24:39.320 --> 0:24:43.320 of the stratosphere you can find ozone. Ozone can absorb 0:24:43.480 --> 0:24:46.439 ultra violet radiation from the Sun. Unlike most of the 0:24:46.480 --> 0:24:50.600 other gases, it actually can absorb some of those short 0:24:50.600 --> 0:24:55.000 wave radiations. So the ozone heats up, which means the 0:24:55.080 --> 0:24:57.960 upper levels of the stratosphere are also warmer than the 0:24:58.000 --> 0:25:02.280 lower levels. Above the amosphere is the miso sphere, where 0:25:02.359 --> 0:25:07.159 temperatures decline again, getting to be the coldest temperatures in 0:25:07.240 --> 0:25:12.720 Earth's atmosphere. Those temperatures hovered around minus degrees fahrenheit or 0:25:12.760 --> 0:25:16.359 minus nineties celsius. And the final layer of the atmosphere 0:25:16.640 --> 0:25:20.640 is the thermosphere, which shares its outer body with space, 0:25:21.200 --> 0:25:24.080 and the air here is not dense at all. It's 0:25:24.080 --> 0:25:30.280 actually pretty widely spread out. The molecules are very thin like, 0:25:30.320 --> 0:25:34.560 it's very thinly populated, the opposite of very dense. In 0:25:34.600 --> 0:25:39.200 other words, the interesting thing here is that the thermosphere 0:25:39.200 --> 0:25:44.440 technically gets really freaking hot. We're talking like degrees fahrenheit 0:25:44.520 --> 0:25:48.600 or shundred degrees celsius. But because those molecules are so 0:25:48.680 --> 0:25:51.960 few and far between, it would not feel hot to 0:25:52.080 --> 0:25:55.040 you because you wouldn't be in contact with these highly 0:25:55.119 --> 0:25:58.280 energized molecules. They're spread too far apart from each other. 0:25:58.480 --> 0:26:01.120 It's kind of like being inside and an enormous arena 0:26:01.240 --> 0:26:05.000 stadium and there are a dozen ping pong balls flying around. 0:26:05.280 --> 0:26:07.240 The Odds of any of those ping pong balls actually 0:26:07.280 --> 0:26:10.280