WEBVTT - Gazing into the Eclipse 0:00:03.120 --> 0:00:06.000 Welcome to Stuff to Blow Your Mind from how Stuff 0:00:06.000 --> 0:00:13.200 Works dot com. Hey, you're welcome to Stuff to Blow 0:00:13.240 --> 0:00:15.840 your Mind. My name is Robert Lamb and I'm Joe McCormick. 0:00:16.120 --> 0:00:18.919 Joe is filling in for Julie this week. You probably 0:00:18.920 --> 0:00:22.959 know Joe from Forward Thinking, our sister podcast and show brand. 0:00:23.120 --> 0:00:27.800 Uh and we're talking about the eclipse. The eclipse, Yes, 0:00:27.840 --> 0:00:32.199 the power of eclipse. That nicotine gum the name of this, 0:00:32.360 --> 0:00:34.040 No way that I think it might just be a 0:00:34.040 --> 0:00:38.280 regular gum. Okay, maybe available on nicotings later. I don't no. 0:00:38.840 --> 0:00:44.560 Eclipses our thing that they are both sort of mundane 0:00:45.080 --> 0:00:51.440 in physical terms, but also quite stunning and terrifying and 0:00:51.960 --> 0:00:56.440 significant throughout the history of humanity, significant to the observer. Yeah, 0:00:56.440 --> 0:00:59.400 because I just want to try to imagine. I know 0:00:59.480 --> 0:01:01.880 you can't really put yourself in this headspace, but just 0:01:01.960 --> 0:01:04.760 try to imagine what it would be like to sort 0:01:04.760 --> 0:01:07.560 of live in a pre scientific time. Maybe you're you're 0:01:07.600 --> 0:01:10.199 part of a you know, a hunter gatherer tribe somewhere 0:01:10.200 --> 0:01:12.600 in the world, and for the first time in your life, 0:01:12.800 --> 0:01:16.880 something very strange happens. One day, the sky starts to 0:01:16.959 --> 0:01:20.920 go dark and you see a black disc pass in 0:01:21.000 --> 0:01:23.679 front of the sun until there's just a ring of 0:01:23.840 --> 0:01:27.320 white fire and the the it's dark in the middle 0:01:27.319 --> 0:01:29.680 of the daytime. You don't know what's going on or 0:01:29.720 --> 0:01:32.240 what's causing this. I have to imagine that it would 0:01:32.280 --> 0:01:36.720 be absolutely terrifying and and completely bizarre. Yeah, I mean 0:01:36.720 --> 0:01:39.520 the cycle of night and day, you know, the one 0:01:39.520 --> 0:01:43.480 of the guiding uh, factors of your life. Even with 0:01:43.520 --> 0:01:46.160 the gay, the guiding factors for any organism, and some 0:01:46.200 --> 0:01:50.080 of the earliest organisms were still based on recognizing when 0:01:50.080 --> 0:01:52.920 it was dark and when it was daylight. And suddenly 0:01:53.240 --> 0:01:55.040 that seems to be thrown out the window by there's 0:01:55.040 --> 0:01:57.920 a random chaotic event. Yeah. Well, i'd say upsetting the 0:01:58.920 --> 0:02:01.200 clear division between night and day is like one of 0:02:01.240 --> 0:02:05.320 the most perverse things you could do to a biological organism. 0:02:05.960 --> 0:02:08.399 I mean, the sun, it's it's the mother of all 0:02:08.440 --> 0:02:10.360 on Earth. When you think about it, all energy on 0:02:10.440 --> 0:02:13.320 Earth is solar energy. Pretty much all all the energy 0:02:13.360 --> 0:02:16.440 we consume, you know, all the food we eat is 0:02:17.080 --> 0:02:21.320 a few steps down the chain, but it's solar energy. Uh. 0:02:21.360 --> 0:02:25.480 And so it's just kind of amazing to imagine not 0:02:25.639 --> 0:02:28.560 knowing what's going on, but seeing that that mother of 0:02:28.600 --> 0:02:33.960 all life suddenly blotted out. And of course maybe not 0:02:34.080 --> 0:02:37.720 equally astounding, but also very strange and and perhaps perverse 0:02:37.760 --> 0:02:41.600 and upsetting is the lunar eclipse. Uh, seeing something happen 0:02:41.680 --> 0:02:43.400 to the moon which to you might have been some 0:02:43.480 --> 0:02:46.480 kind of god or have some other kind of magical significance, 0:02:46.480 --> 0:02:49.240 seeing it change colors, or seeing a shadow pass in 0:02:49.280 --> 0:02:52.600 front of it. Um. So, yeah, I think eclipses are 0:02:52.600 --> 0:02:54.480 going to be a really interesting thing to talk about. 0:02:54.560 --> 0:02:56.640 So you might have heard a couple of years ago 0:02:57.480 --> 0:02:59.640 that the Mayan calendar predicted the end of the world. 0:02:59.639 --> 0:03:02.640 You remember this, I remember hearing a little about it. Yeah, 0:03:03.639 --> 0:03:07.399 way too much. Oh, I got so sick of hearing 0:03:07.440 --> 0:03:10.120 about that. But maybe it's just now been long enough 0:03:10.120 --> 0:03:11.880 that we can bring it up again without making people 0:03:11.919 --> 0:03:14.720 grown too much. But it was supposed to end in 0:03:14.760 --> 0:03:17.840 December twelve. Well, not only did the world not end, 0:03:17.840 --> 0:03:20.680 but the Mayan calendar, actually, this is funny, didn't predict 0:03:20.760 --> 0:03:22.240 the end of the world. Did you know this at 0:03:22.280 --> 0:03:24.760 the time? Um, I don't think I was that informed 0:03:24.760 --> 0:03:26.919 about it. But and it also it was just bombarded 0:03:26.960 --> 0:03:30.040 with that idea of you know, Mayan apocalypse. Yeah, so 0:03:30.280 --> 0:03:33.880 around that time was basically the end of their long 0:03:34.040 --> 0:03:38.280 calendar cycle, which would reset afterwards, so it wasn't really 0:03:38.280 --> 0:03:41.480 a judgment day. It was more like their December thirty first. 0:03:41.520 --> 0:03:44.080 If they had a really, really really long year, it 0:03:44.120 --> 0:03:46.480 would be like somebody looking back at our calendar system 0:03:46.520 --> 0:03:49.120 and thinking of the end of the year, is the 0:03:49.120 --> 0:03:51.040 the end of the of an era, at the end 0:03:51.040 --> 0:03:53.560 of an age and apocalypse? Right, And so they didn't 0:03:53.600 --> 0:03:55.920 predict the end of the world there, but the Mayan 0:03:55.960 --> 0:04:01.480 astronomical calendar actually did make some interesting astronomical predictions. For example, 0:04:01.720 --> 0:04:05.480 there's a book called Astronomy and the Maya Codessees by 0:04:05.600 --> 0:04:10.400 Harvey and Victoria Bricker. So they discussed the ancient Maya 0:04:11.040 --> 0:04:14.640 Mayan astronomical calendars and and they discuss some dating back 0:04:14.680 --> 0:04:18.800 to the eleventh or twelfth centuries CE. And they say 0:04:18.839 --> 0:04:22.560 that these ancient calendars that the Maya had predict the 0:04:22.640 --> 0:04:25.240 date of a solar eclipse that would have been visible 0:04:25.279 --> 0:04:30.320 in July of ninete within about a day of accuracy. 0:04:30.839 --> 0:04:33.560 And it kind of makes you wonder why predicting an 0:04:33.600 --> 0:04:36.360 eclipse would be that important to them. I mean, it's 0:04:36.400 --> 0:04:39.599 not like it had any real like physical effects of 0:04:39.720 --> 0:04:42.440 much significance on Earth. You know, it didn't like it 0:04:42.520 --> 0:04:45.360 wasn't that an eclipse would like destroy all their crops 0:04:45.480 --> 0:04:48.680 or something. So what did it mean? Well, it, I 0:04:48.720 --> 0:04:50.640 mean a lot of it really comes down to, of course, 0:04:50.640 --> 0:04:54.160 there's cosmology, your understanding of what you are as a 0:04:54.240 --> 0:04:56.600 people and what the what the world is, and then 0:04:56.640 --> 0:04:59.839 what the cosmos means. Uh, as well as just basic 0:05:00.360 --> 0:05:04.440 record keeping basic uh observation of the movement of the 0:05:04.480 --> 0:05:06.480 spheres and using this as a as a as a 0:05:06.520 --> 0:05:09.840 way to divide out time. UH. The ancient Maya believed 0:05:09.880 --> 0:05:13.240 in in recurring cycles of creation and destruction, and they 0:05:13.240 --> 0:05:17.200 believe that life was composed of eras lasting around in 0:05:17.279 --> 0:05:20.080 modern years, it would be around a fifty two hundred 0:05:20.160 --> 0:05:23.799 year periods. They believe in a flat, four cornered earth 0:05:23.960 --> 0:05:26.479 that was has been described as being like that of 0:05:27.040 --> 0:05:29.440 the back of a crocodile that's resting in the water, 0:05:29.520 --> 0:05:32.280 you know where it's just the back is emerging. And 0:05:32.480 --> 0:05:34.960 you know. There was additional stuff about the four corners 0:05:35.000 --> 0:05:38.160 and the corresponding gods and UH. And of course there 0:05:38.160 --> 0:05:40.080 are also a lot of rituals in life that are 0:05:40.120 --> 0:05:44.200 dictated by this two hundred and sixty day sacred round calendar. 0:05:44.600 --> 0:05:47.680 So within my culture, you have these priests, these are 0:05:47.680 --> 0:05:50.919 these are the guys that are that are tasked with 0:05:50.920 --> 0:05:53.720 with taking care of upkeep of the calendar as well 0:05:53.760 --> 0:05:57.599 as astronomy. So they're calculating time. Uh, They're they're figuring 0:05:57.600 --> 0:06:01.040 out when festivals should occur, when ceremonies are occurring, uh, 0:06:01.120 --> 0:06:05.560 certain fateful days and seasons. They're divining the future. Uh, 0:06:05.640 --> 0:06:08.000 they're they're trying to figure out the cures for diseases. 0:06:08.040 --> 0:06:10.120 They're writing about it all, and they're keeping track of 0:06:10.120 --> 0:06:13.760 the various genealogies. So in a sense, they are they're 0:06:13.800 --> 0:06:17.599 the keepers of time. They're concerned with Mayan time and 0:06:18.320 --> 0:06:21.120 uh and the Mayan people's place in the universe. Yeah, 0:06:21.160 --> 0:06:26.000 and obviously to the to the Maya, astronomical events had 0:06:26.120 --> 0:06:30.560 real significance, like that they might believe that an astronomical 0:06:30.839 --> 0:06:34.279 portent could give them real information about what would happen 0:06:34.360 --> 0:06:36.640 to them, you know, like it could it could bring 0:06:36.720 --> 0:06:38.840 something bad that would be dangerous, or it could bring 0:06:38.960 --> 0:06:41.159 a good omen So you actually really wanted to be 0:06:41.240 --> 0:06:45.680 able to predict and understand astronomical events. And of course 0:06:45.760 --> 0:06:47.760 the Maya weren't weren't the only ones who had believes 0:06:47.760 --> 0:06:50.239 like this. This is very common all around the world, 0:06:50.279 --> 0:06:53.640 Like the ancient Chinese were very concerned with being able 0:06:53.760 --> 0:06:59.080 to predict eclipses, even the you know, the Anti Kithera mechanism. Yes, 0:06:59.240 --> 0:07:02.159 this is sometimes heard to as the world's first computer 0:07:02.440 --> 0:07:06.600 or like the oldest astronomical calculator in existence. It's a 0:07:06.640 --> 0:07:10.840 mechanical computer that's you know, I think more than two 0:07:10.840 --> 0:07:14.200 thousand years old, that was discovered in a shipwreck in 0:07:14.240 --> 0:07:18.800 the Mediterranean off the coast I believe of the island Antikithera. 0:07:19.440 --> 0:07:21.680 And so they bring this thing up and people have 0:07:21.760 --> 0:07:25.800 been studying it and putting together reconstructions of it. And 0:07:25.840 --> 0:07:29.240 what the people who have studied this mechanism, uh decided 0:07:29.400 --> 0:07:32.520 is that, oh, yeah, so this was an ancient astronomical 0:07:32.560 --> 0:07:36.120 calculator that if you wound the gears, it would tell 0:07:36.200 --> 0:07:40.160 you the placement of different celestial objects and it would 0:07:40.160 --> 0:07:44.640 predict eclipses. So the ancient Greeks or whoever invented this 0:07:45.480 --> 0:07:49.000 amazingly advanced mechanism for the time. We're also very concerned 0:07:49.040 --> 0:07:51.520 with being able to know when was an eclipse going 0:07:51.560 --> 0:07:54.320 to happen, So we're gonna come back and discuss the 0:07:54.400 --> 0:07:58.160 human significance of eclipse more in a few minutes, But 0:07:58.440 --> 0:08:01.640 first we really need to break down the basic science 0:08:01.680 --> 0:08:06.280 of the eclipse, the basic celestial mechanics, uh, that are 0:08:06.280 --> 0:08:08.600 in play here. Okay, Robert, tell me a word that's 0:08:08.640 --> 0:08:12.160 hard to pronounce. Oh, well, you know I can. I 0:08:12.160 --> 0:08:15.200 can probably stumble over any number of difficult words pronounced, 0:08:15.200 --> 0:08:19.840 but the one in question here is ziziggi, which is ziziggi, 0:08:20.080 --> 0:08:25.240 zizigi which is s y z y g y um, 0:08:25.400 --> 0:08:28.240 which is uh. It's like they were playing a joke 0:08:28.320 --> 0:08:30.760 on you. Yeah, I mean, and it only just makes 0:08:30.760 --> 0:08:34.520 me think of Ziggy the cartoon character. But but you know, 0:08:34.559 --> 0:08:37.319 it comes from Ziggy Stardust or Ziggy start us. That's 0:08:37.400 --> 0:08:39.800 why am I going to Ziggi the cartoon character instead 0:08:39.800 --> 0:08:42.800 of Bowie. I don't know, um, but it's a It 0:08:42.840 --> 0:08:48.000 comes from from the Greek um ziogos, which means yoke together. 0:08:48.920 --> 0:08:52.679 Because ultimately we are talking about about convergence here, right, 0:08:53.160 --> 0:08:58.280 So every eclipse is a ziziggi, but not every ziziggi 0:08:58.400 --> 0:09:00.640 is an eclipse. When when a ziggi he occurs with 0:09:00.640 --> 0:09:04.680 celestial bodies, we're talking about a nearly straight line configuration 0:09:05.160 --> 0:09:08.280 of three celestial bodies. In this case, we're talking about 0:09:08.600 --> 0:09:12.040 uh configurations that involved the Sun, Moon, and the Earth 0:09:12.200 --> 0:09:16.400 lining up within a gravitation gravitational system. It also refers 0:09:16.640 --> 0:09:18.920 to when the Sun and the Moon are in conjunction, 0:09:19.640 --> 0:09:22.480 such as a new moon or in opposition, a full moon. 0:09:22.559 --> 0:09:24.880 So those are examples. Those those A full moon is 0:09:24.880 --> 0:09:27.840 a ziziggi. But obviously a full moon is not necessarily 0:09:27.880 --> 0:09:31.040 an eclipse. Okay, you need a full moon for a 0:09:31.120 --> 0:09:33.520 linear eclipse, but more on that later, right, Yeah, okay, 0:09:33.520 --> 0:09:38.160 so I get that. So ziziggi ziziggi, Yes, from the Greek. 0:09:38.240 --> 0:09:40.920 Where does the word eclipse come from? Well, with eclips 0:09:40.960 --> 0:09:42.480 we have to go back to the Greek as well, 0:09:42.559 --> 0:09:50.319 back to eclipses from eclip in, which means to omit fail, suffer, etcetera. 0:09:50.800 --> 0:09:53.600 Uh man see but this kind of dire I mean, 0:09:53.600 --> 0:09:56.439 it kind of drives home the fact that throughout human 0:09:56.480 --> 0:09:58.400 history like this is how we view eclipse. It is 0:09:58.440 --> 0:10:03.080 a thing of of dire omen totally. Well, okay, let's 0:10:03.080 --> 0:10:06.079 look at how lunar eclipses work first, and then we 0:10:06.120 --> 0:10:09.800 can turn the solar eclipses Okay, so pop quiz, which 0:10:09.840 --> 0:10:13.240 is which we you know that one you know that 0:10:13.320 --> 0:10:17.080 one is the Earth blocking light from reflecting off the Moon, 0:10:17.640 --> 0:10:21.400 and the other is the Moon blocking the direct light 0:10:21.440 --> 0:10:23.520 from the Sun that we receive on Earth. But which 0:10:23.559 --> 0:10:26.520 is which? Oh? I mean? So you're basically for a 0:10:26.600 --> 0:10:29.360 solar eclipse, a solar eclipse to occur, the Moon has 0:10:29.400 --> 0:10:31.760 to be in the way, right, So for a solar eclipse, 0:10:32.000 --> 0:10:34.240 the easy way to remember is that you're naming the 0:10:34.280 --> 0:10:37.680 object that's being obscured. So for a solar eclipse that's 0:10:37.679 --> 0:10:40.200 blocking the light from the Sun, the lunar eclipse is 0:10:40.320 --> 0:10:44.000 blocking the reflected light from the Moon. So the lunar 0:10:44.040 --> 0:10:48.280 eclipse happens. It's actually, in the most basic terms, really simple. 0:10:48.360 --> 0:10:52.360 It's when the Moon passes into the shadow of Earth. Uh. 0:10:52.400 --> 0:10:54.920 And when we describe these it will probably really help 0:10:54.960 --> 0:10:56.920 if you will try to do our best. But if 0:10:56.960 --> 0:10:58.880 you look at a picture, this is inherently kind of 0:10:58.880 --> 0:11:01.800 a geometrical or ual phenomenon. You can only say so 0:11:01.920 --> 0:11:05.439 much with words. Um, But if you picture the Earth 0:11:05.640 --> 0:11:08.760 orbiting the Sun and then the Moon orbiting the Earth, 0:11:08.880 --> 0:11:11.840 every now and then the orbits line up so that 0:11:12.360 --> 0:11:16.920 the Moon is directly behind the Earth with respect to 0:11:16.960 --> 0:11:20.040 the Sun. And of course the light we see from 0:11:20.120 --> 0:11:22.880 the moon doesn't come from the Moon, it's reflected from 0:11:22.880 --> 0:11:26.680 the Sun. So if you block the light, you know 0:11:26.800 --> 0:11:29.040 with the Earth's shadow, you're gonna not see much light 0:11:29.080 --> 0:11:31.000 reflected from the moon, or you're gonna see maybe some 0:11:31.120 --> 0:11:34.760 strange colors. So it's like standing in front of a 0:11:34.840 --> 0:11:39.680 movie projection camera facing the screen and you're suddenly asking yourself, 0:11:39.679 --> 0:11:41.360 where did the movie go? Well, the movie is on 0:11:41.360 --> 0:11:43.640 your back now because you're standing in front of the rejector. 0:11:43.800 --> 0:11:47.240 That's a good analogy. Yeah, okay, so the Earth, there 0:11:47.280 --> 0:11:50.560 there are two cone shaped shadows that come off of 0:11:50.559 --> 0:11:52.600 the Earth, and one is sort of the the outward 0:11:52.640 --> 0:11:55.280 spreading one, and one is sort of the inward focusing one. 0:11:55.520 --> 0:11:59.280 The outward spreading one is known as the pin numbra. 0:11:59.800 --> 0:12:02.520 That it's the more diffuse shadow. So that's kind of 0:12:02.640 --> 0:12:06.080 a faint shadow, and you've probably seen, you know yourself, 0:12:06.120 --> 0:12:08.640 in various scenarios that you're actually casting sort of more 0:12:08.640 --> 0:12:11.240 than one shadow, kind of a faint, bigger shadow, and 0:12:11.240 --> 0:12:14.520 then a smaller, more concentrated shadow, and then of course 0:12:14.600 --> 0:12:17.760 the the middle focused inner shadow is the umbra, and 0:12:17.760 --> 0:12:20.440 that's going to be the very dark area that the 0:12:20.440 --> 0:12:24.360 Earth is blocking out a big majority of the Sun's light. 0:12:24.720 --> 0:12:28.679 The pannumbra in cases the umbra, so the pannumbra is wide, 0:12:28.840 --> 0:12:31.079 the umbra is small. In the middle of that is 0:12:31.080 --> 0:12:35.679 futtle bull's eye there in the umbre. Because a lunar 0:12:35.720 --> 0:12:38.640 eclipse can only happen when the Moon is behind the Earth, 0:12:38.760 --> 0:12:41.480 that means that a lunar eclipse also only happens during 0:12:41.480 --> 0:12:43.760 a full moon. A full moon is when the you know, 0:12:43.800 --> 0:12:47.360 the Moon is behind the Earth, reflecting its full face 0:12:47.480 --> 0:12:50.960 to the Earth. It's it's not getting a partially out 0:12:50.960 --> 0:12:55.120 of view, but the Moon orbits the Earth all the time, 0:12:55.840 --> 0:12:59.400 like it makes a full circle roughly every month, right, 0:13:00.400 --> 0:13:03.640 So why don't we see a lunar eclipse every full moon? 0:13:03.679 --> 0:13:05.760 Why don't we see a lunar eclipse every time the 0:13:05.800 --> 0:13:08.600 Moon is on the opposite side of the Earth. So 0:13:08.640 --> 0:13:11.720 you can imagine the Earth and the Sun together on 0:13:11.720 --> 0:13:14.040 what's called an ecliptic plane. They're sort of like sitting 0:13:14.080 --> 0:13:17.000 on a flat surface together. You imagine that's a flat surface, 0:13:17.320 --> 0:13:21.120 and the Moon actually does not orbit the Earth on 0:13:21.240 --> 0:13:25.200 exactly that same plane. It's not flat with the Sun 0:13:25.440 --> 0:13:30.520 and the Earth. It's at a five degree angle from 0:13:30.559 --> 0:13:32.880 that orbit. So if you can imagine this, and it 0:13:33.000 --> 0:13:35.600 probably again will help if you look at a picture, Uh, 0:13:35.800 --> 0:13:37.960 the Earth's orbiting the Sun on a flat plane, and 0:13:38.000 --> 0:13:42.040 then the Moon is orbiting the Earth slightly diagonally. So 0:13:42.120 --> 0:13:44.960 every now and then it is just lined up on 0:13:45.080 --> 0:13:47.839 the sort of up and down y axis with where 0:13:47.880 --> 0:13:50.120 the Sun and the Earth are, and other times it's 0:13:50.120 --> 0:13:52.360 above or below. Okay, So the rotation of the Earth 0:13:52.480 --> 0:13:56.240 is like a brimmed hat that's just on perfectly, whereas 0:13:56.280 --> 0:13:59.800 the Moon's rotation is a cocked hat. Yeah, that's exactly right. 0:14:00.280 --> 0:14:04.200 So those places where the Moon crosses the ecliptic plane 0:14:04.240 --> 0:14:05.840 of the of the Sun and the Earth, those are 0:14:05.880 --> 0:14:09.360 called nodes, and that's where it's lined up correctly to 0:14:09.480 --> 0:14:12.880 be caught right in the middle of of the possible 0:14:13.000 --> 0:14:15.920 eclipse shadow that's being cast by the Earth. When those 0:14:16.040 --> 0:14:18.920 orbits line up perfectly like that is when you're going 0:14:19.000 --> 0:14:22.760 to see a lunar eclipse. It's when the Moon is 0:14:22.800 --> 0:14:26.280 it just the right hy coordinate on this graph. So 0:14:26.360 --> 0:14:28.560 remember those two different shadows I talked about. You have 0:14:28.680 --> 0:14:32.400 the the the umbra and the pin umbra and the 0:14:32.400 --> 0:14:35.240 pin numbre the big shadow. When the moon passes into 0:14:35.240 --> 0:14:38.280 that shadow, sometimes you will get like a pinnumber a 0:14:38.640 --> 0:14:42.400 lunar eclipse, and that can be difficult to see right 0:14:42.480 --> 0:14:45.800 because that shadow isn't so so dense, it's not going 0:14:45.840 --> 0:14:48.480 to block out as much light. And then you can 0:14:48.520 --> 0:14:51.440 also get a partial lunar eclipse where you know, only 0:14:51.520 --> 0:14:53.680 part of the moon is blocked out by the shadow. 0:14:54.040 --> 0:14:56.040 That the really impressive one you want to see is 0:14:56.040 --> 0:14:58.880 the total lunar eclipse where it's just right to pass 0:14:59.080 --> 0:15:04.120 into the umbro, you know, that deep center shadow, and 0:15:04.160 --> 0:15:08.480 that's where the magic happens. And so a lunar eclipses 0:15:08.760 --> 0:15:12.600 are pretty rare. On average, they can happen about three 0:15:12.640 --> 0:15:15.120 times a year, though you can have a year where 0:15:15.120 --> 0:15:18.040 you don't have any eclipses, any lunar eclipses at all 0:15:18.600 --> 0:15:21.800 um And then about a third of these are the 0:15:22.120 --> 0:15:24.840 pin number ones that are harder to see cool, and 0:15:24.880 --> 0:15:28.200 that brings us to solar eclipses. And again it comes 0:15:28.200 --> 0:15:31.640 down to three bodies, you know, again sort of the 0:15:31.840 --> 0:15:34.640 projector something in the way of the projector in the screen. 0:15:35.440 --> 0:15:37.880 But in this case, a solar eclipse is occurring when 0:15:37.880 --> 0:15:41.640 the Moon passes into direct line between the Earth and 0:15:41.760 --> 0:15:44.480 the Sun. So we're the screen as opposed to the 0:15:44.520 --> 0:15:46.920 individual standing in front of the screen in my projector 0:15:46.960 --> 0:15:50.400 analogy here, and solar eclipses are only possible during the 0:15:50.400 --> 0:15:53.960 new moon phase. Uh. This is when the Moon essentially 0:15:53.960 --> 0:15:56.320 plays monkey in the middle Sun and Earth when you 0:15:56.400 --> 0:15:59.880 normally wouldn't see it. Right. So what happens here is 0:16:00.200 --> 0:16:03.600 the Moon's shadow travels over the Earth's surface and blocks 0:16:03.640 --> 0:16:06.880 out the Sun's light as seen from Earth. Again, it 0:16:06.920 --> 0:16:10.000 all comes down to the observer. Because the Moon's the 0:16:10.000 --> 0:16:13.120 moon orbits the Earth at an angle as we already discussed, 0:16:13.160 --> 0:16:16.960 approximately five degrees tilted. The Moon crosses the Earth's over 0:16:17.080 --> 0:16:20.160 doll plane only twice a year, and these team times 0:16:20.160 --> 0:16:23.080 are called eclipse seasons because they are the only times 0:16:23.080 --> 0:16:26.000 when eclipses can occur. So for an eclipse to take place, 0:16:26.080 --> 0:16:28.600 the Moon must be in just the correct phase during 0:16:28.600 --> 0:16:31.160 an eclipse season. Uh, and then that's when the solar 0:16:31.200 --> 0:16:35.360 eclipse occurs. The condition makes this extremely rare. Now, the 0:16:35.360 --> 0:16:37.480 Moon's shadow, as we already mentioned, you have the central 0:16:37.760 --> 0:16:40.920 umbra and then the outer pannumbra. Depending on which part 0:16:41.040 --> 0:16:44.120 of the shadow passes over you, you'll see one of 0:16:44.280 --> 0:16:46.760 three different types of solar eclipses. Because as you've as 0:16:46.760 --> 0:16:49.440 you've probably noted if you've done any kind of reading, 0:16:49.720 --> 0:16:51.920 you know, online, where you're like, when's the next eclipse occurring? 0:16:51.960 --> 0:16:54.040 How am I going to see a solar eclipse? Solar 0:16:54.080 --> 0:16:56.360 eclipse depends on where you are. Yeah, it depends greatly 0:16:56.400 --> 0:16:58.680 on where you are. I mean, I'm already looking ahead 0:16:58.720 --> 0:17:00.480 to the next one, and I think, all right, how 0:17:00.520 --> 0:17:02.360 far do I have to drive? I think I have 0:17:02.360 --> 0:17:04.320 to drive to Kentucky to really get a good view 0:17:04.320 --> 0:17:06.879 of it. And I'm and I'm already thinking about my 0:17:07.000 --> 0:17:10.560 eclipse tourism, because yeah, you could get a total uh 0:17:10.800 --> 0:17:12.560 solar eclipse, and clearly this is the one you want 0:17:12.560 --> 0:17:15.160 to drive for the entire central portion of the Sun 0:17:15.320 --> 0:17:19.440 is blocked out. This is your big iconic Oh my god, 0:17:19.480 --> 0:17:22.080 the world is ending eclipse, right, But then there's the 0:17:22.080 --> 0:17:25.880 partial eclipse where only part of the Sun's surfaces blocked out. Uh. 0:17:25.920 --> 0:17:28.240 And then there's an annuler and this is when only 0:17:28.280 --> 0:17:31.320 a small ring like sliver of light is seen from 0:17:31.359 --> 0:17:33.680 the Sun's disc. Yeah, you can you can actually observe 0:17:33.760 --> 0:17:36.919 the Sun's corona sort of like a plasma halo of 0:17:37.000 --> 0:17:39.880 the Sun around the outside of the black disc, which 0:17:39.920 --> 0:17:42.120 is also pretty Oh my god, the world is gonna end. 0:17:42.720 --> 0:17:45.640 Um And that's a solar eclipse. That's how that works. Yeah, 0:17:46.000 --> 0:17:48.840 we did our best with words. Again, look at a picture. Yeah. 0:17:48.880 --> 0:17:50.639 And also I'm gonna make sure to link out to 0:17:50.800 --> 0:17:53.080 our how stuff works articles on the landing page for 0:17:53.200 --> 0:17:55.240 this episode. We have an article about solar eclipses and 0:17:55.280 --> 0:17:57.960 we have an article about lunar eclipses. Both of those 0:17:58.000 --> 0:18:00.360 have illustrations that will really help you at a better 0:18:00.400 --> 0:18:02.199 grash than what's happening here, as well as more in 0:18:02.280 --> 0:18:06.120 depth explanations. Right. Uh. And we're eventually going to get 0:18:06.160 --> 0:18:09.160 back to what eclipses mean to us in a kind 0:18:09.160 --> 0:18:13.120 of like a dark and magical way. But eclipses also 0:18:13.160 --> 0:18:17.159 do have scientific significance, and I think we should examine 0:18:17.160 --> 0:18:20.800 those claims, both the real scientific significance and the ones 0:18:20.880 --> 0:18:25.040 that have been maybe proposed but not quite validated. Yeah. Indeed, 0:18:25.080 --> 0:18:26.959 and something you might not even think about, like I 0:18:27.000 --> 0:18:29.959 had not really thought about the effect of a solar 0:18:30.000 --> 0:18:33.440 eclipse on terrestrial wind wind, Yeah, which of course makes 0:18:33.480 --> 0:18:36.320 perfect sense, right, because the Sun and its effect on 0:18:36.320 --> 0:18:39.760 the Earth is doing a lot of the work in 0:18:40.080 --> 0:18:44.120 UH in stirring our our atmosphere into the weather patterns 0:18:44.119 --> 0:18:46.199 that we perceive. Yeah, I mean a lot of what 0:18:46.280 --> 0:18:49.640 wind is is exchanging gas from one place to another 0:18:49.680 --> 0:18:52.760 because of heat differentials. And when you block out the Sun, 0:18:52.840 --> 0:18:56.159 obviously you're you're creating as kind of disturbance in the 0:18:56.200 --> 0:19:00.560 normal solar radiation levels you're getting in a certain area. Indeed, 0:19:00.640 --> 0:19:02.639 and UH. In two thousand twelve, a study from the 0:19:02.680 --> 0:19:05.600 University of Reading looked into this UH and found that 0:19:05.640 --> 0:19:09.560 solar eclipses due in fact UH slow the wind down 0:19:09.720 --> 0:19:12.119 and make it change directions. This is a team of 0:19:12.160 --> 0:19:15.520 scientists led by Dr Suzanne Gray, and they compared hourly 0:19:15.560 --> 0:19:18.760 measurements of wind speed and direction from a hundred and 0:19:18.760 --> 0:19:22.800 twenty one weather stations across southern England during the August 0:19:23.160 --> 0:19:26.840 total solar eclipse. Then they compared these to a high 0:19:26.880 --> 0:19:30.800 resolution weather forecast model UH that did not account for 0:19:30.840 --> 0:19:33.399 a solar eclipse. So every what they found is that 0:19:33.440 --> 0:19:37.879 everything lined up on these two different accounts. The model 0:19:38.119 --> 0:19:40.199 that the computer model that does not have an eclipse, 0:19:40.200 --> 0:19:43.280 and then reality which has an eclipse, everything lines up 0:19:43.400 --> 0:19:45.720 right until you get to the eclipse point. Uh. So 0:19:45.760 --> 0:19:48.520 they got to see what the weather would have been 0:19:48.640 --> 0:19:52.480 like without the eclipse occurring at that diversion point, and 0:19:52.520 --> 0:19:55.000 these were the results. They found that average wind speed 0:19:55.040 --> 0:19:58.680 across a cloud free region over southern England dropped by 0:19:58.720 --> 0:20:01.800 point seven meters per second, and that the winds direction 0:20:02.000 --> 0:20:07.120 turned counterclockwise by an average of seventeen degrees. So effectively, 0:20:07.440 --> 0:20:10.359 the eclipse was causing the winds to become more easternly, 0:20:10.600 --> 0:20:14.000 and temperatures also fell by about one degree celsius. Oh 0:20:14.320 --> 0:20:16.359 so did they know that the reason why it was 0:20:16.440 --> 0:20:18.240 changing the mother Was it what I was saying earlier 0:20:18.240 --> 0:20:20.879 about changing the temperature and solar radiation or did it 0:20:21.000 --> 0:20:23.240 have more to do with gravity from the sun and 0:20:23.280 --> 0:20:26.159 the moon. Well, I mean, temperatures fall and there's no 0:20:26.200 --> 0:20:28.600 sunlight obviously, as we see in our regular play of 0:20:28.680 --> 0:20:31.520 night and day. So so that was expected. Wind slow 0:20:31.600 --> 0:20:34.879 went atmosphere um close to the ground cool, So that 0:20:34.960 --> 0:20:37.520 was to be expected, But the changes in wind direction 0:20:37.640 --> 0:20:41.240 were a bit of a surprise. I wonder what could 0:20:41.280 --> 0:20:43.080 caused that? Well, I mean a lot of it just 0:20:43.080 --> 0:20:47.200 comes down to just the complexity of of of weather models, 0:20:47.240 --> 0:20:50.040 you know, and uh, and just how many different factors 0:20:50.080 --> 0:20:54.240 are playing into windspeed in direction right, butterflight's the sun 0:20:54.280 --> 0:20:56.760 in New York, you get rained instead of I mean exactly. 0:20:56.880 --> 0:20:58.840 So that's when we get the butterfly effect. We get 0:20:58.840 --> 0:21:01.040 the the idea of chaos area, and that stems out 0:21:01.040 --> 0:21:05.280 of our attempts to forecast weather in this entirely complex system. 0:21:05.800 --> 0:21:10.159 Here's one I've heard. I remember reading somewhere that apparently 0:21:10.280 --> 0:21:13.560 animals go nuts during an eclipse. Now is this true 0:21:13.640 --> 0:21:16.000 or is this a bunch of bunk? I believe this 0:21:16.080 --> 0:21:18.280 is a bunch of buck based on the research that 0:21:18.320 --> 0:21:23.120 I was looking at. Um basically across the board. There's 0:21:23.160 --> 0:21:28.000 there's no there's no you know, um preternatural response by 0:21:28.040 --> 0:21:31.639 animals to eclipse. Uh. They simply tend to react to 0:21:31.680 --> 0:21:35.040 the darkness as if it were occurring during a typical cycle. Uh. So, 0:21:35.160 --> 0:21:38.879 for instance, scientists have observed this in the vertical migration 0:21:39.119 --> 0:21:43.240 of zooplankton in the ocean due to lunar eclipses, as 0:21:43.240 --> 0:21:46.040 well as I mean countless higher animals when it comes 0:21:46.080 --> 0:21:49.800 to solar eclipses. Because of course, that's the more drastic change. Uh, 0:21:49.960 --> 0:21:52.480