1 00:00:00,200 --> 00:00:02,400 Speaker 1: Hey, please take a second and leave us a review 2 00:00:02,480 --> 00:00:06,279 Speaker 1: on Apple Podcasts, Spotify, or wherever you listen to the podcast. 3 00:00:06,960 --> 00:00:12,720 Speaker 1: Thanks a lot. Hey, Welcome to Science Stuff reproduction of iHeartRadio. 4 00:00:13,039 --> 00:00:15,480 Speaker 1: I'm hore, Hey cham and today we're answering the question 5 00:00:15,880 --> 00:00:20,880 Speaker 1: is the North Pole moving? What actually is the true 6 00:00:20,880 --> 00:00:24,040 Speaker 1: North Pole of the Earth? Is it changing? And should 7 00:00:24,079 --> 00:00:29,200 Speaker 1: Santa Claus consider moving somewhere else. We're going to talk 8 00:00:29,240 --> 00:00:32,440 Speaker 1: to a planetary scientists about this, and as you'll see, 9 00:00:32,640 --> 00:00:35,480 Speaker 1: there are a lot of surprising things to learn about 10 00:00:35,479 --> 00:00:38,800 Speaker 1: what we call the North Pole. Now, this is part 11 00:00:38,840 --> 00:00:41,519 Speaker 1: of a two part holiday special, so be sure to 12 00:00:41,640 --> 00:00:44,480 Speaker 1: check out next week's episode about how the New Year 13 00:00:44,960 --> 00:00:48,880 Speaker 1: is changing. But for now, check under the tree because 14 00:00:49,000 --> 00:00:52,040 Speaker 1: we're going to find out if scientists have been naughty 15 00:00:52,120 --> 00:00:57,760 Speaker 1: or nice in tracking scantus address. Enjoy and happy holidays. 16 00:01:01,720 --> 00:01:04,760 Speaker 1: Hey everyone, So the holidays are upon us, and I 17 00:01:04,760 --> 00:01:07,959 Speaker 1: thought I check in with my friend, planetary scientist, doctor 18 00:01:08,120 --> 00:01:11,800 Speaker 1: Matt Siegler, a professor at the University of Hawaii who 19 00:01:11,800 --> 00:01:16,319 Speaker 1: works with NASA and the European Space Agency on several projects. 20 00:01:16,440 --> 00:01:19,520 Speaker 1: The first thing I asked was what exactly is the 21 00:01:19,680 --> 00:01:24,880 Speaker 1: North Pole? So here's my conversation with doctor Siegler. Well, 22 00:01:24,920 --> 00:01:27,040 Speaker 1: welcome back, doctor Siegler. Happy holidays. 23 00:01:27,200 --> 00:01:28,440 Speaker 2: Oh, happy holidays to you. 24 00:01:28,560 --> 00:01:30,119 Speaker 1: Do you have any big plans for the holidays? You're 25 00:01:30,120 --> 00:01:33,600 Speaker 1: in Hawaii? Is it weird to celebrate Christmas in Hawaii? Yeah? 26 00:01:33,760 --> 00:01:36,000 Speaker 2: This is actually going to be our first Christmas staying 27 00:01:36,040 --> 00:01:38,759 Speaker 2: over in Hawaii, So we'll see what Hawaii Christmas has 28 00:01:38,800 --> 00:01:39,199 Speaker 2: the store. 29 00:01:39,319 --> 00:01:42,400 Speaker 1: Did they just play that song male Likelikimaka twenty four 30 00:01:42,400 --> 00:01:43,000 Speaker 1: to seven there? 31 00:01:44,959 --> 00:01:47,600 Speaker 2: Yeah, yeah, until you go and say, at least it's 32 00:01:47,640 --> 00:01:49,760 Speaker 2: a catchy song. It could be worse, and. 33 00:01:49,720 --> 00:01:51,560 Speaker 1: It always puts a smile on your face. Nothing wrong 34 00:01:51,600 --> 00:01:51,800 Speaker 1: with that. 35 00:01:52,400 --> 00:01:54,200 Speaker 2: We'll see after a whole season of it. 36 00:01:55,240 --> 00:01:57,280 Speaker 1: Well, today, I thought it'd be fun to ask some 37 00:01:57,480 --> 00:02:01,280 Speaker 1: holiday and New Year's related questions about science. And you're 38 00:02:01,280 --> 00:02:03,600 Speaker 1: a planetary scientist, so I thought you'd be the perfect 39 00:02:03,600 --> 00:02:06,400 Speaker 1: person to talk to us about this. Okay, great, Okay. 40 00:02:06,480 --> 00:02:10,000 Speaker 1: The first question is what is the North Pole? Yeah? 41 00:02:10,000 --> 00:02:13,320 Speaker 2: So there are two North poles? Wait what this is 42 00:02:13,320 --> 00:02:15,520 Speaker 2: the first thing to think about. There's the North Pole 43 00:02:15,760 --> 00:02:19,640 Speaker 2: that we spin on right the rotational axis of the Earth. 44 00:02:20,480 --> 00:02:23,919 Speaker 2: But on top of that, there's this magnetic North Pole, 45 00:02:24,320 --> 00:02:27,680 Speaker 2: and we'd really love it if the two lined up right, 46 00:02:27,720 --> 00:02:29,960 Speaker 2: that would make the Earth make sense that there's a 47 00:02:29,960 --> 00:02:32,160 Speaker 2: big magnet in the center of the Earth and it's 48 00:02:32,200 --> 00:02:33,000 Speaker 2: spinning right. 49 00:02:33,200 --> 00:02:33,760 Speaker 1: Uh huh. 50 00:02:33,800 --> 00:02:34,440 Speaker 2: But they don't. 51 00:02:35,480 --> 00:02:39,800 Speaker 1: They don't. Okay, here's the first thing to know about 52 00:02:39,880 --> 00:02:44,120 Speaker 1: the North Pole. There are actually two North poles. There's 53 00:02:44,120 --> 00:02:47,119 Speaker 1: the pole around which the Earth spins, and then there's 54 00:02:47,160 --> 00:02:50,920 Speaker 1: the pole of the Earth's magnetic field. And they're both 55 00:02:51,000 --> 00:02:54,799 Speaker 1: different and they're both changing. Okay, we'll tackle them one 56 00:02:54,840 --> 00:02:58,160 Speaker 1: at a time, and we'll start with the earth spin axis. 57 00:02:59,080 --> 00:03:02,240 Speaker 2: The spin act of the Earth that we rotate around 58 00:03:02,600 --> 00:03:04,960 Speaker 2: does points in different directions over time. 59 00:03:05,040 --> 00:03:08,120 Speaker 1: We're spinning in place. We're also spinning around the Sun. 60 00:03:08,240 --> 00:03:10,560 Speaker 1: But you're saying, on top of that, like we're sort 61 00:03:10,600 --> 00:03:12,760 Speaker 1: of like a top that's kind of wobbling. Yeah. 62 00:03:12,840 --> 00:03:14,440 Speaker 2: Then there are a couple of ways you wabble. There's 63 00:03:14,480 --> 00:03:16,200 Speaker 2: the one where the stick on top of the top 64 00:03:16,280 --> 00:03:17,239 Speaker 2: goes in a little circle. 65 00:03:17,320 --> 00:03:17,840 Speaker 1: Uh huh. 66 00:03:17,880 --> 00:03:20,760 Speaker 2: That's called procession of the orbit. And then there's the 67 00:03:21,080 --> 00:03:23,640 Speaker 2: how the top like tips to the side or not, 68 00:03:23,919 --> 00:03:26,000 Speaker 2: and that's called obliquity change. 69 00:03:26,040 --> 00:03:28,320 Speaker 1: Wait wait, wait, so we're wobbling and we're tilting at 70 00:03:28,320 --> 00:03:29,320 Speaker 1: the same time right now. 71 00:03:29,639 --> 00:03:32,960 Speaker 2: Yes, yes, okay, we're always wobbling and tilting. 72 00:03:33,400 --> 00:03:35,920 Speaker 1: So it turns out the spinning of the Earth is 73 00:03:36,040 --> 00:03:39,840 Speaker 1: changing in two ways. Think of the Earth like a top, 74 00:03:40,240 --> 00:03:42,400 Speaker 1: like the toy you spin and throw on the table. 75 00:03:42,760 --> 00:03:47,400 Speaker 1: That top doesn't usually stay perfectly upright. It wobbles, and 76 00:03:47,560 --> 00:03:52,240 Speaker 1: eventually it starts to tilt. The wobbling is called procession, 77 00:03:52,720 --> 00:03:54,520 Speaker 1: and it's sort of like if you stuck your arm 78 00:03:54,640 --> 00:03:57,600 Speaker 1: up above your head and then waved it around in 79 00:03:57,640 --> 00:04:01,480 Speaker 1: a circle. And the tilting is called obliquity, and it's 80 00:04:01,560 --> 00:04:04,520 Speaker 1: kind of how tilted we are relative to the sun. 81 00:04:04,800 --> 00:04:07,680 Speaker 1: And it turns out both of those things are changing 82 00:04:08,000 --> 00:04:09,440 Speaker 1: with different timescales. 83 00:04:11,160 --> 00:04:15,960 Speaker 2: It happens like the procession. That wobble circle is about 84 00:04:15,960 --> 00:04:17,320 Speaker 2: twenty six thousand years. 85 00:04:17,520 --> 00:04:20,200 Speaker 1: Twenty six thousand years to do one wobble. 86 00:04:20,080 --> 00:04:24,120 Speaker 2: Yes, to be one wah. So the north Star will 87 00:04:24,160 --> 00:04:26,800 Speaker 2: be the north Star, but thirteen thousand years from now 88 00:04:26,880 --> 00:04:29,560 Speaker 2: or so, a star called Vega is going to be 89 00:04:29,600 --> 00:04:30,200 Speaker 2: the north Star. 90 00:04:30,480 --> 00:04:32,719 Speaker 1: Really, we're wobbling that much. 91 00:04:32,680 --> 00:04:35,480 Speaker 2: Yeah, And so we move across the sky like that. 92 00:04:36,920 --> 00:04:40,280 Speaker 1: Yes, the north Star won't always be the north Star. 93 00:04:40,800 --> 00:04:43,320 Speaker 1: And this one just effect whether you can navigate in 94 00:04:43,400 --> 00:04:47,400 Speaker 1: the open ocean. It could affect who you are if 95 00:04:47,440 --> 00:04:49,080 Speaker 1: you believe in astrology. 96 00:04:50,520 --> 00:04:54,320 Speaker 2: And one of the big ramifications this change, this procession 97 00:04:54,640 --> 00:04:58,480 Speaker 2: causes those zodiac signs to change by about one sign 98 00:04:58,520 --> 00:04:59,719 Speaker 2: every two thousand years. 99 00:05:00,160 --> 00:05:02,159 Speaker 1: You mean they shift in the sky kind of. Yeah. 100 00:05:02,200 --> 00:05:05,240 Speaker 2: So the zodiac sign is the sign that's behind the 101 00:05:05,279 --> 00:05:08,359 Speaker 2: sun the day you were born, but now, because of 102 00:05:08,440 --> 00:05:12,599 Speaker 2: this procession of the equinoxes and moving about in two 103 00:05:12,600 --> 00:05:16,279 Speaker 2: thousand years, your zodiac sign is actually off by a 104 00:05:16,360 --> 00:05:19,880 Speaker 2: month from what the ancient Greeks use the zodiac signs. 105 00:05:19,920 --> 00:05:22,120 Speaker 1: Wait, wait a minute, are you saying that astrology has not 106 00:05:22,279 --> 00:05:24,520 Speaker 1: kept up with modern physics. Is that what you're saying. 107 00:05:24,760 --> 00:05:28,560 Speaker 2: Yeah, most astrologers have not kept up with modern astronomy 108 00:05:28,960 --> 00:05:32,160 Speaker 2: and the change of the zodiac signs. I hope this 109 00:05:32,200 --> 00:05:35,600 Speaker 2: doesn't like end anyone's marriage or cause anyone trouble that 110 00:05:35,600 --> 00:05:38,120 Speaker 2: you've been reading the wrong zodiac sign your whole life. 111 00:05:38,200 --> 00:05:39,880 Speaker 1: It's like, oh, I thought I loved you because you 112 00:05:39,920 --> 00:05:42,400 Speaker 1: were a Gemini, but it turns out, actually, in two 113 00:05:42,400 --> 00:05:45,360 Speaker 1: thousand years, you're gonna be a pisson. It's over. It's over. 114 00:05:45,480 --> 00:05:48,280 Speaker 2: Yeah, love is not eternal. It's only for roughly a 115 00:05:48,320 --> 00:05:49,520 Speaker 2: two thousand year period. 116 00:05:51,600 --> 00:05:54,400 Speaker 1: Yes, the wabbling of the Earth means you can't really 117 00:05:54,480 --> 00:05:59,200 Speaker 1: trust zodiac signs, which I know is totally a Scorpio 118 00:05:59,279 --> 00:06:01,600 Speaker 1: thing to say. And it turns out we have all 119 00:06:01,640 --> 00:06:06,080 Speaker 1: the other planets to blame for this wobble. Wow, I'd 120 00:06:06,080 --> 00:06:08,480 Speaker 1: never review that. And why are we processing? Is that 121 00:06:08,480 --> 00:06:10,680 Speaker 1: the right word? Why are we wobbling? 122 00:06:11,200 --> 00:06:14,320 Speaker 2: So that has to do a little bit with how 123 00:06:14,560 --> 00:06:17,440 Speaker 2: all the planets yank on each other. Jupiter is the 124 00:06:17,440 --> 00:06:20,240 Speaker 2: big dominant one in the Solar system, so that has 125 00:06:20,279 --> 00:06:22,960 Speaker 2: a big effect on us. Venus is the closest one 126 00:06:22,960 --> 00:06:25,120 Speaker 2: to us, so that has an effect. And the way 127 00:06:25,320 --> 00:06:28,560 Speaker 2: all the gravity of these different planets kind of yank 128 00:06:28,600 --> 00:06:31,120 Speaker 2: on each other a little bit causes these tops to 129 00:06:31,200 --> 00:06:35,040 Speaker 2: wobble in this weird way. Whoah, And so we influence 130 00:06:35,080 --> 00:06:38,640 Speaker 2: how Venus wobbles and Mars wobbles. 131 00:06:38,880 --> 00:06:42,200 Speaker 1: Interesting, So right now we are breaking up marriages in bars, 132 00:06:42,640 --> 00:06:48,320 Speaker 1: I guess. So that's our wobble. But like doctor Seger says, 133 00:06:48,640 --> 00:06:53,040 Speaker 1: our overall tilt relative to the Sun is also changing 134 00:06:53,560 --> 00:06:56,839 Speaker 1: about every forty one thousand years. 135 00:06:57,720 --> 00:07:00,160 Speaker 2: That's our obliquity. So it's the twenty three and a 136 00:07:00,200 --> 00:07:03,920 Speaker 2: half degree tilt that the Earth has that causes seasons 137 00:07:03,960 --> 00:07:06,440 Speaker 2: and all that, and that wobbles a little, but only 138 00:07:06,520 --> 00:07:09,520 Speaker 2: like about a degree or so over time, I see. 139 00:07:09,560 --> 00:07:12,920 Speaker 2: And that's good because that little wobble of the degree 140 00:07:13,040 --> 00:07:16,440 Speaker 2: or so and the power round or oval Earth's orbit 141 00:07:16,560 --> 00:07:20,400 Speaker 2: is all those things mess with our climate. So when 142 00:07:20,400 --> 00:07:23,760 Speaker 2: we go in and out of ice ages, it's because 143 00:07:23,880 --> 00:07:28,320 Speaker 2: of these orbital changes, these things called Malankovitch cycles. 144 00:07:28,000 --> 00:07:29,280 Speaker 1: No kidding, go on. 145 00:07:29,560 --> 00:07:33,800 Speaker 2: But luckily this tilt, the obliquity doesn't change very much 146 00:07:34,000 --> 00:07:37,360 Speaker 2: because the Moon actually is so big and massive compared 147 00:07:37,400 --> 00:07:39,520 Speaker 2: to the Earth, and that's enough that it kind of 148 00:07:39,560 --> 00:07:41,000 Speaker 2: acts as a balance. 149 00:07:41,880 --> 00:07:43,680 Speaker 1: It gives more like inertia kind of. 150 00:07:43,920 --> 00:07:46,720 Speaker 2: Yeah, And so that moment of inertia of the Earth 151 00:07:46,760 --> 00:07:49,600 Speaker 2: Moon system is pretty big, and so we don't wobble 152 00:07:49,880 --> 00:07:53,160 Speaker 2: that much other planets. Wow, And so we don't have 153 00:07:53,360 --> 00:07:56,640 Speaker 2: as extreme ice ages as Mars does for instance. 154 00:07:57,160 --> 00:07:58,520 Speaker 1: Interesting, all thanks of the Moon. 155 00:07:58,800 --> 00:08:04,560 Speaker 2: Yeah, thank you many yes. 156 00:08:02,720 --> 00:08:06,320 Speaker 1: So this holiday season, if you're feeling thankful, be sure 157 00:08:06,360 --> 00:08:08,760 Speaker 1: to thank the Moon for the fact we're not living 158 00:08:09,040 --> 00:08:11,880 Speaker 1: in an ice age. Okay, when we come back, we're 159 00:08:11,920 --> 00:08:14,640 Speaker 1: going to tackle the other North pole of the Earth 160 00:08:14,920 --> 00:08:17,400 Speaker 1: the magnetic north pole, and we're going to talk about 161 00:08:17,400 --> 00:08:20,480 Speaker 1: how it used to be in the south pole. Stay 162 00:08:20,520 --> 00:08:35,520 Speaker 1: merry with us, We'll be right back. Welcome back. We're 163 00:08:35,559 --> 00:08:38,840 Speaker 1: celebrating the holidays by asking if the North pole is moving, 164 00:08:39,120 --> 00:08:43,640 Speaker 1: and the answer is yes. We just talked about how 165 00:08:43,640 --> 00:08:47,040 Speaker 1: the spinning axis of the Earth is changing. It's wobbling 166 00:08:47,280 --> 00:08:51,080 Speaker 1: and it's tilting in cycles that last twenty six and 167 00:08:51,240 --> 00:08:53,800 Speaker 1: forty one thousand years due to the polling of the 168 00:08:53,880 --> 00:08:57,360 Speaker 1: Earth by the other planets in the Solar System. Now, 169 00:08:57,360 --> 00:08:59,640 Speaker 1: as it turns out, there is a third way in 170 00:08:59,760 --> 00:09:02,559 Speaker 1: which the spinning north pole of the Earth is changing, 171 00:09:02,920 --> 00:09:07,800 Speaker 1: and that is because of plate tectonics. Here's planetary scientists, 172 00:09:07,920 --> 00:09:09,160 Speaker 1: doctor Matt Siegler. 173 00:09:10,559 --> 00:09:14,400 Speaker 2: If you slowly move continents around over you know, millions 174 00:09:14,440 --> 00:09:18,440 Speaker 2: of years, that will actually change the axis along which 175 00:09:18,440 --> 00:09:19,000 Speaker 2: we rotate. 176 00:09:19,160 --> 00:09:23,040 Speaker 1: No wait, like the moving continents can cause the Earth 177 00:09:23,080 --> 00:09:24,800 Speaker 1: to wobble too, yeah, or. 178 00:09:24,920 --> 00:09:28,400 Speaker 2: Cause the spin axis to change, because the axis upon 179 00:09:28,480 --> 00:09:31,559 Speaker 2: which we spin is controlled by that moment of inertia 180 00:09:31,640 --> 00:09:34,599 Speaker 2: of the planet and by where you put your mass 181 00:09:34,679 --> 00:09:35,360 Speaker 2: on that ball. 182 00:09:36,480 --> 00:09:39,400 Speaker 1: What doctor Ziegler is saying is that as the continents 183 00:09:39,480 --> 00:09:43,840 Speaker 1: move because of plate tectonics. That changes how the mass 184 00:09:43,880 --> 00:09:47,200 Speaker 1: of the Earth is distributed, which can change which way 185 00:09:47,280 --> 00:09:50,280 Speaker 1: the Earth is spinning, sort of like if you're an 186 00:09:50,280 --> 00:09:52,840 Speaker 1: ice skater and you're spinning on the ice, if you 187 00:09:52,880 --> 00:09:55,800 Speaker 1: suddenly move an arm or one leg out, you're going 188 00:09:55,840 --> 00:09:57,360 Speaker 1: to be thrown out of balance. 189 00:09:59,559 --> 00:10:03,320 Speaker 2: That's a called true polar wander. Whoah, if it's different 190 00:10:03,360 --> 00:10:06,559 Speaker 2: from this apparent polar wander, this motion that I was 191 00:10:06,559 --> 00:10:09,640 Speaker 2: talking about relative to the zodiac signs uh huh. But 192 00:10:09,880 --> 00:10:13,760 Speaker 2: true polar wander is that the spin axis can actually 193 00:10:13,920 --> 00:10:17,880 Speaker 2: change if you move enough mass around woa, like continent 194 00:10:17,960 --> 00:10:20,080 Speaker 2: scale masses, big big masses. 195 00:10:20,200 --> 00:10:22,480 Speaker 1: So then the spin axis has been changing relative to 196 00:10:22,520 --> 00:10:22,960 Speaker 1: the Earth. 197 00:10:23,400 --> 00:10:26,360 Speaker 2: Yes, but that's over a very slow time, right, because 198 00:10:26,360 --> 00:10:29,440 Speaker 2: it takes millions of billions of years for continents to 199 00:10:29,559 --> 00:10:30,720 Speaker 2: really move that much. 200 00:10:32,280 --> 00:10:34,960 Speaker 1: And now we get to the magnetic north pole of 201 00:10:35,000 --> 00:10:38,240 Speaker 1: the Earth. As you probably know, the Earth acts like 202 00:10:38,280 --> 00:10:42,640 Speaker 1: a giant magnet. He creates a big magnetic field and 203 00:10:42,679 --> 00:10:45,800 Speaker 1: the center of that field is a line that runs 204 00:10:45,880 --> 00:10:48,440 Speaker 1: through the Earth. One side of that line is what 205 00:10:48,480 --> 00:10:50,959 Speaker 1: we call the North pole and the other side is 206 00:10:51,000 --> 00:10:54,480 Speaker 1: what we call the South cole. That magnetic North Pole 207 00:10:54,800 --> 00:10:58,760 Speaker 1: is where all compasses point to, and according to doctor Siegler, 208 00:10:58,920 --> 00:11:02,880 Speaker 1: where that North pole is has been changing a lot. 209 00:11:03,520 --> 00:11:05,960 Speaker 1: I mean, Santa, you better pack your bags. 210 00:11:08,679 --> 00:11:13,079 Speaker 2: So the magnetic pole of the Earth has actually moved 211 00:11:13,200 --> 00:11:16,720 Speaker 2: quite a bit. So right now it's kind of in 212 00:11:16,840 --> 00:11:20,840 Speaker 2: northern Canada somewhere, but a couple hundred years ago it 213 00:11:20,920 --> 00:11:24,120 Speaker 2: was in Siberia, and a couple hundred years before that 214 00:11:24,200 --> 00:11:26,800 Speaker 2: it had moved around Greenland, and then now it's like 215 00:11:27,280 --> 00:11:29,040 Speaker 2: kind of moving back towards Siberia. 216 00:11:29,760 --> 00:11:33,240 Speaker 1: That's right. The magnetic north pole changes on the scale 217 00:11:33,320 --> 00:11:37,160 Speaker 1: of a hundred years. In fact, it's changing right now. 218 00:11:37,880 --> 00:11:40,640 Speaker 1: Scientists estimate that the North pole is moving on the 219 00:11:40,679 --> 00:11:44,320 Speaker 1: surface of the Earth about a kilometer a week, which 220 00:11:44,360 --> 00:11:47,680 Speaker 1: is about one hundred and forty meters a day. This 221 00:11:47,840 --> 00:11:51,440 Speaker 1: means where your compass points to today is different from 222 00:11:51,440 --> 00:11:54,520 Speaker 1: where your compass will point to tomorrow. And where is 223 00:11:54,520 --> 00:11:59,560 Speaker 1: it going to point next. Scientists don't really know. 224 00:12:00,520 --> 00:12:03,840 Speaker 2: So the magnetic north pole has been doing its own 225 00:12:03,920 --> 00:12:08,439 Speaker 2: like chaotic journey around roughly the physical spinning north Pole. 226 00:12:08,520 --> 00:12:11,559 Speaker 1: Uh huh, but it's chaotic, I mean it's unpredictable. 227 00:12:11,840 --> 00:12:15,920 Speaker 2: Yeah, it kind of changes its direction sometimes and it's 228 00:12:16,040 --> 00:12:19,880 Speaker 2: going on its weird separate wobble, but it's a little 229 00:12:19,880 --> 00:12:21,080 Speaker 2: more bizarre how it does. 230 00:12:22,120 --> 00:12:24,920 Speaker 1: So we can't tell where the magnetic north pole is 231 00:12:24,960 --> 00:12:28,800 Speaker 1: going to move to. It's unpredictable. And that is because 232 00:12:28,800 --> 00:12:32,800 Speaker 1: of what actually makes the Earth's magnetic field, which is 233 00:12:33,000 --> 00:12:34,160 Speaker 1: the Earth's core. 234 00:12:35,800 --> 00:12:40,040 Speaker 2: So Earth has a big iron core, iron, nickel, sulfur 235 00:12:40,120 --> 00:12:42,640 Speaker 2: or a few other molecules in there or whatever, and 236 00:12:43,200 --> 00:12:45,760 Speaker 2: that core is about as big as Mars, right, So 237 00:12:45,800 --> 00:12:47,160 Speaker 2: it's a big why core? 238 00:12:47,360 --> 00:12:48,160 Speaker 1: Right? Yeah? 239 00:12:48,240 --> 00:12:51,120 Speaker 2: Yeah, So Mars is about half the diameter of Earth, 240 00:12:51,200 --> 00:12:53,840 Speaker 2: and so we have this huge chunk of iron in 241 00:12:53,880 --> 00:12:55,560 Speaker 2: the center of the Earth as big as Mars. 242 00:12:55,880 --> 00:12:57,839 Speaker 1: That's incredible. I didn't know if that big. 243 00:12:58,080 --> 00:13:02,880 Speaker 2: Yeah, it's really high pressure. It's really hot down there, 244 00:13:03,120 --> 00:13:06,120 Speaker 2: and it's hot enough that at least for the outer 245 00:13:06,240 --> 00:13:10,319 Speaker 2: part of that core, it becomes liquid. And then roughly 246 00:13:10,440 --> 00:13:13,520 Speaker 2: the inner third of that liquid core is under so 247 00:13:13,720 --> 00:13:18,320 Speaker 2: much pressure that it's a solid again, right, like solid 248 00:13:18,360 --> 00:13:19,480 Speaker 2: hunk of iron. 249 00:13:19,320 --> 00:13:22,559 Speaker 1: At the very very center. Yeah. Okay, okay, So we've. 250 00:13:22,400 --> 00:13:25,800 Speaker 2: Got a little ball of iron swimming in a Mars 251 00:13:25,880 --> 00:13:30,960 Speaker 2: size ball of liquid iron, and those two things spin 252 00:13:31,600 --> 00:13:35,160 Speaker 2: kind of differently from each other really, yeah, such that 253 00:13:35,240 --> 00:13:37,440 Speaker 2: the solid one is kind of like the spinning blade 254 00:13:37,480 --> 00:13:40,800 Speaker 2: of the blender, and then you have the liquid around 255 00:13:40,840 --> 00:13:43,120 Speaker 2: that's kind of getting churned up and mixed up. 256 00:13:43,920 --> 00:13:45,920 Speaker 1: So at the center of the Earth, we have a 257 00:13:46,000 --> 00:13:49,960 Speaker 1: solid ball of iron that's about two thousand kilometers wide, 258 00:13:50,280 --> 00:13:53,880 Speaker 1: and that's spinning inside of a swirling ocean of liquid 259 00:13:53,920 --> 00:13:58,720 Speaker 1: iron that's about two thousand kilometers And all that moving 260 00:13:58,800 --> 00:14:02,920 Speaker 1: and spinning iron is what causes the earth magnetic field. 261 00:14:03,840 --> 00:14:06,920 Speaker 2: And so that ore is mostly made of iron, which 262 00:14:07,320 --> 00:14:11,719 Speaker 2: you know conducts electricity. And when you take a conductor 263 00:14:11,840 --> 00:14:14,600 Speaker 2: and you spin it, you cause a magnetic field. 264 00:14:15,559 --> 00:14:18,040 Speaker 1: Just see any metal, if you spin any metal. Yeah, 265 00:14:18,200 --> 00:14:20,600 Speaker 1: Like if I take a bar of iron and I 266 00:14:20,640 --> 00:14:22,560 Speaker 1: spin it, it's going to create a magnetic. 267 00:14:22,200 --> 00:14:25,600 Speaker 2: Field, yes, And then that causes a magnetic field in 268 00:14:25,640 --> 00:14:29,320 Speaker 2: the core. And then there's this feedback where the magnetic 269 00:14:29,360 --> 00:14:32,320 Speaker 2: field gets stronger and stronger, and that's what we call 270 00:14:32,400 --> 00:14:33,560 Speaker 2: a magnetic dynamo. 271 00:14:34,640 --> 00:14:37,560 Speaker 1: So the spinning iron core of the Earth is what 272 00:14:37,680 --> 00:14:40,960 Speaker 1: makes the earth magnetic field. But here's the thing. The 273 00:14:41,000 --> 00:14:45,760 Speaker 1: part of the core that's liquid doesn't spin and flow smoothly. Yes, 274 00:14:45,880 --> 00:14:49,920 Speaker 1: turbulence and swirls and eddies, and all that turbulence makes 275 00:14:49,960 --> 00:14:53,160 Speaker 1: the overall magnetic field on predictable. 276 00:14:55,120 --> 00:14:59,040 Speaker 2: The solid core is spinning. In the liquid core, it 277 00:14:59,120 --> 00:15:03,360 Speaker 2: causes little turbulence and eddies and such in the liquid core. 278 00:15:03,680 --> 00:15:04,400 Speaker 1: Uh huh. 279 00:15:04,440 --> 00:15:08,720 Speaker 2: Those are motion of electrical conducting material, and so those 280 00:15:08,720 --> 00:15:11,960 Speaker 2: all cause a little magnetic field, uh uh huh. And 281 00:15:12,080 --> 00:15:15,040 Speaker 2: they all kind of build together and give you north 282 00:15:15,080 --> 00:15:17,320 Speaker 2: pole on a south pole for the whole Earth. 283 00:15:17,440 --> 00:15:20,560 Speaker 1: Oh, it's like there's a massive magnetic fields down there 284 00:15:20,560 --> 00:15:23,200 Speaker 1: in the Earth's core, but overall you can they just 285 00:15:23,240 --> 00:15:25,080 Speaker 1: add up together. By the time you pull out to 286 00:15:25,200 --> 00:15:27,520 Speaker 1: like the Earth's surface, it just feels like one big 287 00:15:27,600 --> 00:15:29,320 Speaker 1: giant magnetic field exactly. 288 00:15:30,280 --> 00:15:33,760 Speaker 2: And so because you have all this weird turbulence going on, 289 00:15:34,160 --> 00:15:36,880 Speaker 2: it doesn't actually always line up in the right direction 290 00:15:37,000 --> 00:15:38,520 Speaker 2: to be pointing due. 291 00:15:38,320 --> 00:15:39,640 Speaker 1: North right, uh huh. 292 00:15:39,720 --> 00:15:42,280 Speaker 2: It kind of wobbles around a lot, right, as all 293 00:15:42,280 --> 00:15:46,640 Speaker 2: these little eddies and currents going on inside interact. Sometimes 294 00:15:46,640 --> 00:15:48,960 Speaker 2: they'll line up with the spin axis of the Earth, 295 00:15:49,000 --> 00:15:52,440 Speaker 2: and sometimes they don't. And that's happening on the scale 296 00:15:52,480 --> 00:15:54,760 Speaker 2: of hundreds of years. It's like a tug of war 297 00:15:54,840 --> 00:15:58,040 Speaker 2: where the pole of the magnetic field of the Earth 298 00:15:58,120 --> 00:15:59,400 Speaker 2: is just migrating around. 299 00:16:01,080 --> 00:16:03,520 Speaker 1: Yes, if you look up pictures of where the magnetic 300 00:16:03,600 --> 00:16:07,080 Speaker 1: north pole has been where scientists think it may go next, 301 00:16:07,520 --> 00:16:10,240 Speaker 1: it's not a smooth path. It looks like the path 302 00:16:10,400 --> 00:16:13,640 Speaker 1: a drunk elf would take if they had too much echnogy. 303 00:16:15,400 --> 00:16:19,440 Speaker 1: And it gets even wilder. Scientists believe that in the past, 304 00:16:19,720 --> 00:16:24,160 Speaker 1: the magnetic field of the Earth has even flipped, it 305 00:16:24,200 --> 00:16:27,560 Speaker 1: has turned completely around to the point where the north 306 00:16:27,640 --> 00:16:30,920 Speaker 1: pole was actually in the south pole of the Earth. 307 00:16:31,640 --> 00:16:36,400 Speaker 1: That would be a huge move for Santa Claus. So 308 00:16:36,440 --> 00:16:39,160 Speaker 1: when we come back, we'll talk about why this happened, 309 00:16:39,400 --> 00:16:41,680 Speaker 1: how we know it happened, and whether we can tell 310 00:16:41,720 --> 00:16:45,360 Speaker 1: if it's going to happen again. So ho ho, hold on, 311 00:16:45,840 --> 00:17:01,800 Speaker 1: don't go anywhere, We'll be right back. Hey, welcome back. 312 00:17:02,960 --> 00:17:05,840 Speaker 1: We're talking about whether the North pole is changing, and 313 00:17:06,000 --> 00:17:09,879 Speaker 1: so far we've learned that it's totally changing. The spin 314 00:17:10,000 --> 00:17:13,240 Speaker 1: ax of the Earth is changing in like three different ways, 315 00:17:13,480 --> 00:17:17,120 Speaker 1: and the magnetic north pole of to Earth is also changing. 316 00:17:17,440 --> 00:17:21,959 Speaker 1: It's meandering around worse than a drunk elf today after Christmas. 317 00:17:22,240 --> 00:17:25,159 Speaker 1: In fact, scientists believe that the magnetic north pole of 318 00:17:25,160 --> 00:17:29,359 Speaker 1: the Earth can even switch and flip upside down, and 319 00:17:29,400 --> 00:17:32,359 Speaker 1: that this has happened several times in the history of 320 00:17:32,400 --> 00:17:32,800 Speaker 1: the Earth. 321 00:17:34,800 --> 00:17:37,520 Speaker 2: Yeah, So that's where it gets even crazier. Right, So 322 00:17:37,560 --> 00:17:42,000 Speaker 2: we have all of these spinning, rotating fluids and the 323 00:17:42,119 --> 00:17:44,800 Speaker 2: solid core of the Earth. So you have all these 324 00:17:45,080 --> 00:17:48,080 Speaker 2: eddies all interacting with each other and right now all 325 00:17:48,160 --> 00:17:51,439 Speaker 2: kind of lining up where the net magnetic field points 326 00:17:51,480 --> 00:17:54,399 Speaker 2: to the north pole. But because they're all fluid and 327 00:17:54,440 --> 00:17:57,440 Speaker 2: can interact in these weird ways, they can all kind 328 00:17:57,440 --> 00:18:02,200 Speaker 2: of work together and flip, and so sometimes the north 329 00:18:02,280 --> 00:18:06,879 Speaker 2: pole magnetically becomes the South pole. Why and vice versa. 330 00:18:08,200 --> 00:18:10,600 Speaker 1: Yes, the magnetic north pole of the Earth can change 331 00:18:10,680 --> 00:18:13,639 Speaker 1: so much it can even end up in the South pole. 332 00:18:15,000 --> 00:18:19,000 Speaker 1: So your compass would point to Antarctica as being due north. 333 00:18:19,480 --> 00:18:22,679 Speaker 1: And this has not just happened once before. It's happened 334 00:18:22,720 --> 00:18:26,159 Speaker 1: maybe thousands of times in the history of the Earth. 335 00:18:27,080 --> 00:18:30,600 Speaker 2: And that switch between the north pole pointing north and 336 00:18:30,720 --> 00:18:35,439 Speaker 2: the north pole pointing south magnetically has happened roughly every 337 00:18:35,800 --> 00:18:39,480 Speaker 2: five hundred thousand years or so. Sometimes it's longer, sometimes 338 00:18:39,520 --> 00:18:40,040 Speaker 2: it's shorter. 339 00:18:40,960 --> 00:18:43,359 Speaker 1: Okay, you might be wondering how we know this and 340 00:18:43,440 --> 00:18:46,080 Speaker 1: the answer is that there's a record of the Earth's 341 00:18:46,119 --> 00:18:49,639 Speaker 1: magnetic field at the bottom of the ocean. At the 342 00:18:49,680 --> 00:18:52,840 Speaker 1: middle of the oceans, there are enormous seams where the 343 00:18:52,920 --> 00:18:57,719 Speaker 1: Earth's tectonic plates are separating, and as they separate, lava 344 00:18:57,800 --> 00:19:03,440 Speaker 1: comes up, creezes and forms thew c floor. Now, when 345 00:19:03,480 --> 00:19:06,399 Speaker 1: the lava freezes and becomes rock, the metal in the 346 00:19:06,520 --> 00:19:10,960 Speaker 1: rock records the magnetic field at the time the lava froze. 347 00:19:12,320 --> 00:19:15,040 Speaker 1: So if you measure the magnetism of the rocks the 348 00:19:15,080 --> 00:19:18,639 Speaker 1: bottom of the ocean, you'll see bands parallel to the 349 00:19:18,680 --> 00:19:22,920 Speaker 1: seam or ocean ridge where the rocks magnetism points one 350 00:19:22,960 --> 00:19:26,359 Speaker 1: way and then another way, and then another way. And 351 00:19:26,440 --> 00:19:29,600 Speaker 1: from the age of the rocks, scientists can tell that 352 00:19:29,720 --> 00:19:34,159 Speaker 1: this flipping of Earth's magnetic field happens on average about 353 00:19:34,280 --> 00:19:37,720 Speaker 1: every five hundred thousand years or so. Sometimes it happens 354 00:19:37,760 --> 00:19:41,840 Speaker 1: more frequently and sometimes less frequently. The last time it 355 00:19:41,960 --> 00:19:46,040 Speaker 1: happened was almost eight hundred thousand years ago. But here's 356 00:19:46,080 --> 00:19:49,800 Speaker 1: the big mystery. Scientists don't know if the magnetic north 357 00:19:49,840 --> 00:19:54,360 Speaker 1: pole switches to the south pole really quickly or really slowly, 358 00:19:55,040 --> 00:19:56,479 Speaker 1: and what happens in between. 359 00:19:58,560 --> 00:20:01,879 Speaker 2: It's unclear how long it takes the switch from pointing 360 00:20:01,920 --> 00:20:04,600 Speaker 2: north to pointing south. Does it happen in one day 361 00:20:04,800 --> 00:20:07,000 Speaker 2: or does it happen in a couple thousand years? 362 00:20:07,080 --> 00:20:07,600 Speaker 1: We don't know. 363 00:20:07,880 --> 00:20:10,560 Speaker 2: Most estimates are its probably takes a few thousand years, 364 00:20:10,720 --> 00:20:14,240 Speaker 2: But that is a timescale that's difficult to measure on 365 00:20:14,280 --> 00:20:17,680 Speaker 2: the geologic record, right, we can measure hundreds of thousands 366 00:20:17,720 --> 00:20:20,800 Speaker 2: of years. Yeah, that we can measure pretty precisely. When 367 00:20:20,800 --> 00:20:23,880 Speaker 2: you were talking about is it six days or two 368 00:20:23,920 --> 00:20:27,840 Speaker 2: thousand years, like, we can't tell. It's a little tricky 369 00:20:27,960 --> 00:20:31,639 Speaker 2: to tell that precision. That's wild and it's probably a 370 00:20:31,680 --> 00:20:34,439 Speaker 2: little different every time, right, because it's driven by this 371 00:20:34,560 --> 00:20:38,159 Speaker 2: chaotic stirring of the core of the Earth, right, and 372 00:20:38,240 --> 00:20:41,600 Speaker 2: so that's when the Earth's magnetic field will flip, uh huh. 373 00:20:41,680 --> 00:20:45,639 Speaker 2: You'll kind of get this weird period in between where 374 00:20:45,880 --> 00:20:49,160 Speaker 2: the compass would point to all sorts of random directions, right. 375 00:20:49,440 --> 00:20:52,280 Speaker 1: Like there might be a six day or one thousand 376 00:20:52,359 --> 00:20:55,480 Speaker 1: year period where your compass will point to like Panama 377 00:20:55,640 --> 00:20:57,040 Speaker 1: true north of the Earth. 378 00:20:57,200 --> 00:21:00,719 Speaker 2: Yes, because that's where the magnetic field happens to be 379 00:21:00,720 --> 00:21:05,639 Speaker 2: popping out that day. And then from tradition or whatever, 380 00:21:05,680 --> 00:21:08,000 Speaker 2: from the record that we see, it will eventually end 381 00:21:08,119 --> 00:21:11,080 Speaker 2: up where the north pole of your compass would point south, 382 00:21:11,480 --> 00:21:13,720 Speaker 2: and then we'll stay that way, probably for five hundred 383 00:21:13,720 --> 00:21:15,840 Speaker 2: thousand years, and then flip back the other way. 384 00:21:15,880 --> 00:21:18,639 Speaker 1: So the fact that my compass points north now it 385 00:21:18,760 --> 00:21:20,680 Speaker 1: just happens to be like that. Now, at some point 386 00:21:20,720 --> 00:21:22,439 Speaker 1: it's going to change, and it has changed before. 387 00:21:22,640 --> 00:21:25,760 Speaker 2: Yeah, there's a whole history of how this affected early 388 00:21:26,160 --> 00:21:30,159 Speaker 2: navigation when the fourteen hundreds plus, right, especially when you 389 00:21:30,480 --> 00:21:34,240 Speaker 2: live in Europe and you're at pretty high latitudes, that 390 00:21:34,320 --> 00:21:37,879 Speaker 2: little difference matters whether the magnetic north is right on 391 00:21:37,920 --> 00:21:41,399 Speaker 2: the north pole, uh huh. And so this inability to 392 00:21:41,480 --> 00:21:44,760 Speaker 2: actually tell where doe north was really one of the 393 00:21:44,800 --> 00:21:48,000 Speaker 2: things that led the history of exploration of the world 394 00:21:48,280 --> 00:21:51,320 Speaker 2: by the Europeans to be so so kind of random 395 00:21:51,359 --> 00:21:53,480 Speaker 2: in a way where oh, yeah, sometimes we ended up 396 00:21:53,520 --> 00:21:55,879 Speaker 2: in the wrong place and we thought it was somewhere else. 397 00:21:56,960 --> 00:21:59,639 Speaker 1: It's because the magnetic hole moved. 398 00:22:00,119 --> 00:22:03,240 Speaker 2: Yeah, the compass was just not a reliable way to 399 00:22:03,359 --> 00:22:04,400 Speaker 2: navigate perfectly. 400 00:22:05,680 --> 00:22:09,480 Speaker 1: Okay, So that's the Earth's magnetic north pole and it's 401 00:22:09,560 --> 00:22:12,280 Speaker 1: moving all over the place, and the spinning north poole 402 00:22:12,320 --> 00:22:15,600 Speaker 1: of the Earth is also changing. Does this mean Santa 403 00:22:15,840 --> 00:22:18,800 Speaker 1: is doomed to have to keep moving around forever, like 404 00:22:18,880 --> 00:22:27,040 Speaker 1: maybe keep his toy workshop and reindeer stables in trailers. Well, 405 00:22:27,080 --> 00:22:30,000 Speaker 1: it turns out there is a third North pool here 406 00:22:30,040 --> 00:22:34,880 Speaker 1: on Earth, and that's the one defined by our GPS systems. 407 00:22:36,000 --> 00:22:39,120 Speaker 2: A lot of the expeditions in the late eighteen hundreds 408 00:22:39,119 --> 00:22:41,880 Speaker 2: and early nineteen hundreds to the north and south pole 409 00:22:42,040 --> 00:22:45,639 Speaker 2: of the Earth were driven by trying to find where 410 00:22:45,680 --> 00:22:49,000 Speaker 2: the heck this actual magnetic North pole wash. And then 411 00:22:49,040 --> 00:22:51,000 Speaker 2: they got there and realized, oh, it's moving. 412 00:22:51,680 --> 00:22:53,679 Speaker 1: Like I put a flag here last time, it's not 413 00:22:53,720 --> 00:22:54,280 Speaker 1: here anymore. 414 00:22:54,359 --> 00:22:58,800 Speaker 2: Yeah, exactly, And that's part of why. Now we don't 415 00:22:58,880 --> 00:23:02,720 Speaker 2: navigate by compass is, but we navigate with Global Positioning 416 00:23:02,720 --> 00:23:07,960 Speaker 2: satellites right, GPS system. We've created a more reliable navigation 417 00:23:08,400 --> 00:23:10,680 Speaker 2: pole than the magnetic north Oh. 418 00:23:10,720 --> 00:23:12,840 Speaker 1: That's a third pole. Now we have like a GPS 419 00:23:12,840 --> 00:23:14,040 Speaker 1: pole exactly. Yeah. 420 00:23:14,119 --> 00:23:17,360 Speaker 2: Yeah, we have a way to navigate ourselves with respect 421 00:23:17,440 --> 00:23:20,399 Speaker 2: to the GPS and that won't wobble with the Earth. 422 00:23:20,480 --> 00:23:24,159 Speaker 2: It won't with the magnetic field. It's kind of a 423 00:23:24,240 --> 00:23:25,880 Speaker 2: fixed thing that we can reference. 424 00:23:27,000 --> 00:23:30,480 Speaker 1: Okay, great, we can use GPS. Does that mean that 425 00:23:30,520 --> 00:23:34,720 Speaker 1: we finally have a fixed North pole one that doesn't change, 426 00:23:36,119 --> 00:23:36,920 Speaker 1: Not quite. 427 00:23:38,480 --> 00:23:42,680 Speaker 2: It might drift a little over time. The gravity field 428 00:23:42,720 --> 00:23:45,720 Speaker 2: of the Earth is not perfectly symmetric, right, It's not 429 00:23:45,880 --> 00:23:48,880 Speaker 2: the perfect round ball in terms of gravity. The equator 430 00:23:48,960 --> 00:23:53,280 Speaker 2: is a little fatter than the poles because of us spinning. 431 00:23:53,560 --> 00:23:55,320 Speaker 1: You mean the equator has a different body type. 432 00:23:55,520 --> 00:23:58,200 Speaker 2: Yeah, yeah, yes, yes, the equator has a different body type. 433 00:23:59,119 --> 00:24:01,520 Speaker 2: So if you have a satellite that's trying to go 434 00:24:01,560 --> 00:24:05,240 Speaker 2: around the North Pole, uh huh, the equator will cause 435 00:24:05,280 --> 00:24:08,800 Speaker 2: a little gravity that would yank it to be eventually 436 00:24:08,880 --> 00:24:10,280 Speaker 2: be in an equatorial orbit. 437 00:24:10,480 --> 00:24:13,760 Speaker 1: Wait, you mean like our GPS satellite system could be 438 00:24:14,080 --> 00:24:17,320 Speaker 1: kind of drifting or getting wobbled and we might not 439 00:24:17,400 --> 00:24:18,359 Speaker 1: even know it. Yeah. 440 00:24:18,480 --> 00:24:21,199 Speaker 2: Maybe, And there are all sorts of asymmetries. There's this 441 00:24:21,240 --> 00:24:24,680 Speaker 2: big bulge from the spinning of the equator, but then 442 00:24:24,720 --> 00:24:27,359 Speaker 2: there's also just kind of random places that have more 443 00:24:27,480 --> 00:24:30,320 Speaker 2: or less gravity. Huh. And they had something to do 444 00:24:30,400 --> 00:24:33,040 Speaker 2: with the structure of the continents and the structure of 445 00:24:33,040 --> 00:24:36,520 Speaker 2: the mantle and how much density there are in different places. 446 00:24:36,520 --> 00:24:38,879 Speaker 2: So if you're over the Himalayas, the gravity is a 447 00:24:38,880 --> 00:24:40,600 Speaker 2: little different than if you're over Iowa. 448 00:24:42,040 --> 00:24:45,080 Speaker 1: So now we have three poles on Earth. We have 449 00:24:45,200 --> 00:24:48,280 Speaker 1: the spinning axes, the magnetic North Pole, and now we 450 00:24:48,320 --> 00:24:52,080 Speaker 1: have this GPS reference and all three I mean, they're 451 00:24:52,119 --> 00:24:55,480 Speaker 1: all tied together obviously through physics, but they're not necessarily 452 00:24:55,520 --> 00:24:57,960 Speaker 1: the same or staying constant to each other. 453 00:24:58,200 --> 00:25:02,399 Speaker 2: Yeah, over longer pier then we probably care about. But 454 00:25:02,720 --> 00:25:06,000 Speaker 2: if you're trying to navigate a fighter jet by GPS, 455 00:25:06,040 --> 00:25:07,600 Speaker 2: you probably do care about. 456 00:25:09,359 --> 00:25:11,240 Speaker 1: But if you try to fly the same jet in 457 00:25:11,280 --> 00:25:13,639 Speaker 1: one hundred thousand years, who knows if you'll end up 458 00:25:13,640 --> 00:25:15,000 Speaker 1: in the same spot exactly. 459 00:25:17,400 --> 00:25:21,520 Speaker 2: If your instruments haven't updated their internal system. 460 00:25:21,280 --> 00:25:23,679 Speaker 1: You've literally shaken my world. Mad, I feel like I 461 00:25:23,720 --> 00:25:26,840 Speaker 1: can't trust GPS anymore. Like I thought that was the 462 00:25:26,880 --> 00:25:29,240 Speaker 1: gold standard. The Earth might be doing all kinds of 463 00:25:29,280 --> 00:25:31,480 Speaker 1: crazy things inside of this GPS sphere. 464 00:25:31,840 --> 00:25:34,080 Speaker 2: I think we can very slowly, very slowly. 465 00:25:35,440 --> 00:25:37,680 Speaker 1: Well, I think to summarize, like, if you were looking 466 00:25:37,680 --> 00:25:39,520 Speaker 1: for the North Pole, you could look it up in 467 00:25:39,560 --> 00:25:42,120 Speaker 1: three different systems and you could end up in three 468 00:25:42,119 --> 00:25:43,359 Speaker 1: different places. 469 00:25:43,600 --> 00:25:46,680 Speaker 2: Yeah, so the North Pole itself has a little mystery 470 00:25:46,800 --> 00:25:49,639 Speaker 2: around it, right, uh huh. Depending on how you want 471 00:25:49,680 --> 00:25:52,000 Speaker 2: to address it. It could be in a little bit 472 00:25:52,040 --> 00:25:57,040 Speaker 2: different place. So that's why it's a good place for Santa. 473 00:25:57,320 --> 00:26:00,640 Speaker 1: It all makes sense. Santa has a degreen physics and 474 00:26:01,160 --> 00:26:03,879 Speaker 1: planetary science, and he's like, where's the one place on 475 00:26:03,920 --> 00:26:05,880 Speaker 1: Earth where it's going to be extra hard for people 476 00:26:05,920 --> 00:26:07,639 Speaker 1: to find me? The North Pole? 477 00:26:07,880 --> 00:26:11,000 Speaker 2: Exactly, and especially because the North Pole is covered with 478 00:26:11,280 --> 00:26:14,439 Speaker 2: sea ice. Right, uh huh, antarcticle, we have land, we 479 00:26:14,480 --> 00:26:17,080 Speaker 2: have land at the South Pole, but the North Pole 480 00:26:17,160 --> 00:26:23,320 Speaker 2: is ice, so that drifts around too a so, so yeah, 481 00:26:23,400 --> 00:26:24,960 Speaker 2: I think it's it's a safe spot. 482 00:26:27,600 --> 00:26:29,639 Speaker 1: Now does that mean Santa has to move every couple 483 00:26:29,600 --> 00:26:31,679 Speaker 1: of thousand years or do you think he likes the 484 00:26:31,760 --> 00:26:33,960 Speaker 1: drifting part of it, like he's a drifter at heart. 485 00:26:35,119 --> 00:26:39,040 Speaker 2: Yes, Santa's a drifter at heart. Let the elves control 486 00:26:39,080 --> 00:26:40,000 Speaker 2: the GPS system. 487 00:26:40,160 --> 00:26:44,080 Speaker 1: Oh my goodness, you said on a conspiracy theory. Maybe 488 00:26:44,119 --> 00:26:45,800 Speaker 1: in a given year, if kids get a lot of 489 00:26:45,840 --> 00:26:49,240 Speaker 1: GPS based toys, that's Santa trying to cover his tracks. 490 00:26:49,560 --> 00:26:53,639 Speaker 1: Oh yeah, He's like, let them find me. Here's all 491 00:26:53,640 --> 00:26:56,919 Speaker 1: these GPS A little do they know I'm not at 492 00:26:57,000 --> 00:26:58,160 Speaker 1: the GPS North Pole? 493 00:26:58,320 --> 00:27:02,800 Speaker 2: Give them compasses that don't go the wrong no pole, Yeah, 494 00:27:02,960 --> 00:27:05,720 Speaker 2: lead them astray. Yeah, so maybe this whole magnetic North 495 00:27:05,760 --> 00:27:08,639 Speaker 2: Pole migrating so much is just a way of hiding 496 00:27:08,680 --> 00:27:12,240 Speaker 2: the secret location of the workshop. Pretty much darker tone 497 00:27:12,280 --> 00:27:14,400 Speaker 2: to Santa than I've ever heard before. 498 00:27:14,920 --> 00:27:17,200 Speaker 1: Do you think he lived in Antarctica then, like five 499 00:27:17,280 --> 00:27:18,920 Speaker 1: hundred thousand years ago? Yeah? 500 00:27:19,000 --> 00:27:23,320 Speaker 2: Does he migrate with the migration of the magnetic spinpole 501 00:27:23,520 --> 00:27:25,320 Speaker 2: or the physical spin pole? 502 00:27:25,480 --> 00:27:27,240 Speaker 1: He's like, well, I'm just waiting for the time where 503 00:27:27,240 --> 00:27:29,400 Speaker 1: the North Pole points in Panama, and then I'll move 504 00:27:29,480 --> 00:27:33,360 Speaker 1: to Panama in the tropics and live at the beach. Yeah, exactly, 505 00:27:34,920 --> 00:27:39,600 Speaker 1: all right. Well, uh, dear Santa, if you're listening, please 506 00:27:39,600 --> 00:27:42,240 Speaker 1: don't put me on your naughty list or divulging your 507 00:27:42,359 --> 00:27:45,520 Speaker 1: North Pole secrets. But if you do, please don't put 508 00:27:45,560 --> 00:27:48,640 Speaker 1: a piece of coal in my stocking. Instead, leave a magnet. 509 00:27:49,080 --> 00:27:51,080 Speaker 1: I could use it to make a compass that'll work 510 00:27:51,160 --> 00:27:54,679 Speaker 1: for at least a few hundred thousand years. And to 511 00:27:54,720 --> 00:27:58,000 Speaker 1: everyone else, thanks for joining us. Happy holidays for everyone 512 00:27:58,000 --> 00:28:03,000 Speaker 1: here at sign Stuff. See you next time you've been 513 00:28:03,000 --> 00:28:07,240 Speaker 1: listening to Science Stuff. The production of iHeartRadio written and 514 00:28:07,320 --> 00:28:10,760 Speaker 1: produced by me or Hey Cham, edited by Rose Seguda 515 00:28:11,160 --> 00:28:15,480 Speaker 1: executive producer Jerry Rowland and audio engineer and mixer Kasey Peckram. 516 00:28:15,680 --> 00:28:17,800 Speaker 1: And you can follow me on social media. Just search 517 00:28:17,880 --> 00:28:20,960 Speaker 1: for PhD Comics and the name of your favorite platform. 518 00:28:21,200 --> 00:28:24,120 Speaker 1: Be sure to subscribe to sign Stuff on the iHeartRadio app, 519 00:28:24,160 --> 00:28:27,399 Speaker 1: Apple Podcasts or wherever you get your podcasts, and please 520 00:28:27,600 --> 00:28:36,440 Speaker 1: tell your friends we'll be back next Wednesday with another episode.