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Speaker 1: Thanks a lot. Hey, Welcome to Science Stuff reproduction of iHeartRadio.
Speaker 1: I'm hore, Hey cham and today we're answering the question
Speaker 1: is the North Pole moving? What actually is the true
Speaker 1: North Pole of the Earth? Is it changing? And should
Speaker 1: Santa Claus consider moving somewhere else. We're going to talk
Speaker 1: to a planetary scientists about this, and as you'll see,
Speaker 1: there are a lot of surprising things to learn about
Speaker 1: what we call the North Pole. Now, this is part
Speaker 1: of a two part holiday special, so be sure to
Speaker 1: check out next week's episode about how the New Year
Speaker 1: is changing. But for now, check under the tree because
Speaker 1: we're going to find out if scientists have been naughty
Speaker 1: or nice in tracking scantus address. Enjoy and happy holidays.
Speaker 1: Hey everyone, So the holidays are upon us, and I
Speaker 1: thought I check in with my friend, planetary scientist, doctor
Speaker 1: Matt Siegler, a professor at the University of Hawaii who
Speaker 1: works with NASA and the European Space Agency on several projects.
Speaker 1: The first thing I asked was what exactly is the
Speaker 1: North Pole? So here's my conversation with doctor Siegler. Well,
Speaker 1: welcome back, doctor Siegler. Happy holidays.
Speaker 2: Oh, happy holidays to you.
Speaker 1: Do you have any big plans for the holidays? You're
Speaker 1: in Hawaii? Is it weird to celebrate Christmas in Hawaii? Yeah?
Speaker 2: This is actually going to be our first Christmas staying
Speaker 2: over in Hawaii, So we'll see what Hawaii Christmas has
Speaker 2: the store.
Speaker 1: Did they just play that song male Likelikimaka twenty four
Speaker 1: to seven there?
Speaker 2: Yeah, yeah, until you go and say, at least it's
Speaker 2: a catchy song. It could be worse, and.
Speaker 1: It always puts a smile on your face. Nothing wrong
Speaker 1: with that.
Speaker 2: We'll see after a whole season of it.
Speaker 1: Well, today, I thought it'd be fun to ask some
Speaker 1: holiday and New Year's related questions about science. And you're
Speaker 1: a planetary scientist, so I thought you'd be the perfect
Speaker 1: person to talk to us about this. Okay, great, Okay.
Speaker 1: The first question is what is the North Pole? Yeah?
Speaker 2: So there are two North poles? Wait what this is
Speaker 2: the first thing to think about. There's the North Pole
Speaker 2: that we spin on right the rotational axis of the Earth.
Speaker 2: But on top of that, there's this magnetic North Pole,
Speaker 2: and we'd really love it if the two lined up right,
Speaker 2: that would make the Earth make sense that there's a
Speaker 2: big magnet in the center of the Earth and it's
Speaker 2: spinning right.
Speaker 1: Uh huh.
Speaker 2: But they don't.
Speaker 1: They don't. Okay, here's the first thing to know about
Speaker 1: the North Pole. There are actually two North poles. There's
Speaker 1: the pole around which the Earth spins, and then there's
Speaker 1: the pole of the Earth's magnetic field. And they're both
Speaker 1: different and they're both changing. Okay, we'll tackle them one
Speaker 1: at a time, and we'll start with the earth spin axis.
Speaker 2: The spin act of the Earth that we rotate around
Speaker 2: does points in different directions over time.
Speaker 1: We're spinning in place. We're also spinning around the Sun.
Speaker 1: But you're saying, on top of that, like we're sort
Speaker 1: of like a top that's kind of wobbling. Yeah.
Speaker 2: Then there are a couple of ways you wabble. There's
Speaker 2: the one where the stick on top of the top
Speaker 2: goes in a little circle.
Speaker 1: Uh huh.
Speaker 2: That's called procession of the orbit. And then there's the
Speaker 2: how the top like tips to the side or not,
Speaker 2: and that's called obliquity change.
Speaker 1: Wait wait, wait, so we're wobbling and we're tilting at
Speaker 1: the same time right now.
Speaker 2: Yes, yes, okay, we're always wobbling and tilting.
Speaker 1: So it turns out the spinning of the Earth is
Speaker 1: changing in two ways. Think of the Earth like a top,
Speaker 1: like the toy you spin and throw on the table.
Speaker 1: That top doesn't usually stay perfectly upright. It wobbles, and
Speaker 1: eventually it starts to tilt. The wobbling is called procession,
Speaker 1: and it's sort of like if you stuck your arm
Speaker 1: up above your head and then waved it around in
Speaker 1: a circle. And the tilting is called obliquity, and it's
Speaker 1: kind of how tilted we are relative to the sun.
Speaker 1: And it turns out both of those things are changing
Speaker 1: with different timescales.
Speaker 2: It happens like the procession. That wobble circle is about
Speaker 2: twenty six thousand years.
Speaker 1: Twenty six thousand years to do one wobble.
Speaker 2: Yes, to be one wah. So the north Star will
Speaker 2: be the north Star, but thirteen thousand years from now
Speaker 2: or so, a star called Vega is going to be
Speaker 2: the north Star.
Speaker 1: Really, we're wobbling that much.
Speaker 2: Yeah, And so we move across the sky like that.
Speaker 1: Yes, the north Star won't always be the north Star.
Speaker 1: And this one just effect whether you can navigate in
Speaker 1: the open ocean. It could affect who you are if
Speaker 1: you believe in astrology.
Speaker 2: And one of the big ramifications this change, this procession
Speaker 2: causes those zodiac signs to change by about one sign
Speaker 2: every two thousand years.
Speaker 1: You mean they shift in the sky kind of. Yeah.
Speaker 2: So the zodiac sign is the sign that's behind the
Speaker 2: sun the day you were born, but now, because of
Speaker 2: this procession of the equinoxes and moving about in two
Speaker 2: thousand years, your zodiac sign is actually off by a
Speaker 2: month from what the ancient Greeks use the zodiac signs.
Speaker 1: Wait, wait a minute, are you saying that astrology has not
Speaker 1: kept up with modern physics. Is that what you're saying.
Speaker 2: Yeah, most astrologers have not kept up with modern astronomy
Speaker 2: and the change of the zodiac signs. I hope this
Speaker 2: doesn't like end anyone's marriage or cause anyone trouble that
Speaker 2: you've been reading the wrong zodiac sign your whole life.
Speaker 1: It's like, oh, I thought I loved you because you
Speaker 1: were a Gemini, but it turns out, actually, in two
Speaker 1: thousand years, you're gonna be a pisson. It's over. It's over.
Speaker 2: Yeah, love is not eternal. It's only for roughly a
Speaker 2: two thousand year period.
Speaker 1: Yes, the wabbling of the Earth means you can't really
Speaker 1: trust zodiac signs, which I know is totally a Scorpio
Speaker 1: thing to say. And it turns out we have all
Speaker 1: the other planets to blame for this wobble. Wow, I'd
Speaker 1: never review that. And why are we processing? Is that
Speaker 1: the right word? Why are we wobbling?
Speaker 2: So that has to do a little bit with how
Speaker 2: all the planets yank on each other. Jupiter is the
Speaker 2: big dominant one in the Solar system, so that has
Speaker 2: a big effect on us. Venus is the closest one
Speaker 2: to us, so that has an effect. And the way
Speaker 2: all the gravity of these different planets kind of yank
Speaker 2: on each other a little bit causes these tops to
Speaker 2: wobble in this weird way. Whoah, And so we influence
Speaker 2: how Venus wobbles and Mars wobbles.
Speaker 1: Interesting, So right now we are breaking up marriages in bars,
Speaker 1: I guess. So that's our wobble. But like doctor Seger says,
Speaker 1: our overall tilt relative to the Sun is also changing
Speaker 1: about every forty one thousand years.
Speaker 2: That's our obliquity. So it's the twenty three and a
Speaker 2: half degree tilt that the Earth has that causes seasons
Speaker 2: and all that, and that wobbles a little, but only
Speaker 2: like about a degree or so over time, I see.
Speaker 2: And that's good because that little wobble of the degree
Speaker 2: or so and the power round or oval Earth's orbit
Speaker 2: is all those things mess with our climate. So when
Speaker 2: we go in and out of ice ages, it's because
Speaker 2: of these orbital changes, these things called Malankovitch cycles.
Speaker 1: No kidding, go on.
Speaker 2: But luckily this tilt, the obliquity doesn't change very much
Speaker 2: because the Moon actually is so big and massive compared
Speaker 2: to the Earth, and that's enough that it kind of
Speaker 2: acts as a balance.
Speaker 1: It gives more like inertia kind of.
Speaker 2: Yeah, And so that moment of inertia of the Earth
Speaker 2: Moon system is pretty big, and so we don't wobble
Speaker 2: that much other planets. Wow, And so we don't have
Speaker 2: as extreme ice ages as Mars does for instance.
Speaker 1: Interesting, all thanks of the Moon.
Speaker 2: Yeah, thank you many yes.
Speaker 1: So this holiday season, if you're feeling thankful, be sure
Speaker 1: to thank the Moon for the fact we're not living
Speaker 1: in an ice age. Okay, when we come back, we're
Speaker 1: going to tackle the other North pole of the Earth
Speaker 1: the magnetic north pole, and we're going to talk about
Speaker 1: how it used to be in the south pole. Stay
Speaker 1: merry with us, We'll be right back. Welcome back. We're
Speaker 1: celebrating the holidays by asking if the North pole is moving,
Speaker 1: and the answer is yes. We just talked about how
Speaker 1: the spinning axis of the Earth is changing. It's wobbling
Speaker 1: and it's tilting in cycles that last twenty six and
Speaker 1: forty one thousand years due to the polling of the
Speaker 1: Earth by the other planets in the Solar System. Now,
Speaker 1: as it turns out, there is a third way in
Speaker 1: which the spinning north pole of the Earth is changing,
Speaker 1: and that is because of plate tectonics. Here's planetary scientists,
Speaker 1: doctor Matt Siegler.
Speaker 2: If you slowly move continents around over you know, millions
Speaker 2: of years, that will actually change the axis along which
Speaker 2: we rotate.
Speaker 1: No wait, like the moving continents can cause the Earth
Speaker 1: to wobble too, yeah, or.
Speaker 2: Cause the spin axis to change, because the axis upon
Speaker 2: which we spin is controlled by that moment of inertia
Speaker 2: of the planet and by where you put your mass
Speaker 2: on that ball.
Speaker 1: What doctor Ziegler is saying is that as the continents
Speaker 1: move because of plate tectonics. That changes how the mass
Speaker 1: of the Earth is distributed, which can change which way
Speaker 1: the Earth is spinning, sort of like if you're an
Speaker 1: ice skater and you're spinning on the ice, if you
Speaker 1: suddenly move an arm or one leg out, you're going
Speaker 1: to be thrown out of balance.
Speaker 2: That's a called true polar wander. Whoah, if it's different
Speaker 2: from this apparent polar wander, this motion that I was
Speaker 2: talking about relative to the zodiac signs uh huh. But
Speaker 2: true polar wander is that the spin axis can actually
Speaker 2: change if you move enough mass around woa, like continent
Speaker 2: scale masses, big big masses.
Speaker 1: So then the spin axis has been changing relative to
Speaker 1: the Earth.
Speaker 2: Yes, but that's over a very slow time, right, because
Speaker 2: it takes millions of billions of years for continents to
Speaker 2: really move that much.
Speaker 1: And now we get to the magnetic north pole of
Speaker 1: the Earth. As you probably know, the Earth acts like
Speaker 1: a giant magnet. He creates a big magnetic field and
Speaker 1: the center of that field is a line that runs
Speaker 1: through the Earth. One side of that line is what
Speaker 1: we call the North pole and the other side is
Speaker 1: what we call the South cole. That magnetic North Pole
Speaker 1: is where all compasses point to, and according to doctor Siegler,
Speaker 1: where that North pole is has been changing a lot.
Speaker 1: I mean, Santa, you better pack your bags.
Speaker 2: So the magnetic pole of the Earth has actually moved
Speaker 2: quite a bit. So right now it's kind of in
Speaker 2: northern Canada somewhere, but a couple hundred years ago it
Speaker 2: was in Siberia, and a couple hundred years before that
Speaker 2: it had moved around Greenland, and then now it's like
Speaker 2: kind of moving back towards Siberia.
Speaker 1: That's right. The magnetic north pole changes on the scale
Speaker 1: of a hundred years. In fact, it's changing right now.
Speaker 1: Scientists estimate that the North pole is moving on the
Speaker 1: surface of the Earth about a kilometer a week, which
Speaker 1: is about one hundred and forty meters a day. This
Speaker 1: means where your compass points to today is different from
Speaker 1: where your compass will point to tomorrow. And where is
Speaker 1: it going to point next. Scientists don't really know.
Speaker 2: So the magnetic north pole has been doing its own
Speaker 2: like chaotic journey around roughly the physical spinning north Pole.
Speaker 1: Uh huh, but it's chaotic, I mean it's unpredictable.
Speaker 2: Yeah, it kind of changes its direction sometimes and it's
Speaker 2: going on its weird separate wobble, but it's a little
Speaker 2: more bizarre how it does.
Speaker 1: So we can't tell where the magnetic north pole is
Speaker 1: going to move to. It's unpredictable. And that is because
Speaker 1: of what actually makes the Earth's magnetic field, which is
Speaker 1: the Earth's core.
Speaker 2: So Earth has a big iron core, iron, nickel, sulfur
Speaker 2: or a few other molecules in there or whatever, and
Speaker 2: that core is about as big as Mars, right, So
Speaker 2: it's a big why core?
Speaker 1: Right? Yeah?
Speaker 2: Yeah, So Mars is about half the diameter of Earth,
Speaker 2: and so we have this huge chunk of iron in
Speaker 2: the center of the Earth as big as Mars.
Speaker 1: That's incredible. I didn't know if that big.
Speaker 2: Yeah, it's really high pressure. It's really hot down there,
Speaker 2: and it's hot enough that at least for the outer
Speaker 2: part of that core, it becomes liquid. And then roughly
Speaker 2: the inner third of that liquid core is under so
Speaker 2: much pressure that it's a solid again, right, like solid
Speaker 2: hunk of iron.
Speaker 1: At the very very center. Yeah. Okay, okay, So we've.
Speaker 2: Got a little ball of iron swimming in a Mars
Speaker 2: size ball of liquid iron, and those two things spin
Speaker 2: kind of differently from each other really, yeah, such that
Speaker 2: the solid one is kind of like the spinning blade
Speaker 2: of the blender, and then you have the liquid around
Speaker 2: that's kind of getting churned up and mixed up.
Speaker 1: So at the center of the Earth, we have a
Speaker 1: solid ball of iron that's about two thousand kilometers wide,
Speaker 1: and that's spinning inside of a swirling ocean of liquid
Speaker 1: iron that's about two thousand kilometers And all that moving
Speaker 1: and spinning iron is what causes the earth magnetic field.
Speaker 2: And so that ore is mostly made of iron, which
Speaker 2: you know conducts electricity. And when you take a conductor
Speaker 2: and you spin it, you cause a magnetic field.
Speaker 1: Just see any metal, if you spin any metal. Yeah,
Speaker 1: Like if I take a bar of iron and I
Speaker 1: spin it, it's going to create a magnetic.
Speaker 2: Field, yes, And then that causes a magnetic field in
Speaker 2: the core. And then there's this feedback where the magnetic
Speaker 2: field gets stronger and stronger, and that's what we call
Speaker 2: a magnetic dynamo.
Speaker 1: So the spinning iron core of the Earth is what
Speaker 1: makes the earth magnetic field. But here's the thing. The
Speaker 1: part of the core that's liquid doesn't spin and flow smoothly. Yes,
Speaker 1: turbulence and swirls and eddies, and all that turbulence makes
Speaker 1: the overall magnetic field on predictable.
Speaker 2: The solid core is spinning. In the liquid core, it
Speaker 2: causes little turbulence and eddies and such in the liquid core.
Speaker 1: Uh huh.
Speaker 2: Those are motion of electrical conducting material, and so those
Speaker 2: all cause a little magnetic field, uh uh huh. And
Speaker 2: they all kind of build together and give you north
Speaker 2: pole on a south pole for the whole Earth.
Speaker 1: Oh, it's like there's a massive magnetic fields down there
Speaker 1: in the Earth's core, but overall you can they just
Speaker 1: add up together. By the time you pull out to
Speaker 1: like the Earth's surface, it just feels like one big
Speaker 1: giant magnetic field exactly.
Speaker 2: And so because you have all this weird turbulence going on,
Speaker 2: it doesn't actually always line up in the right direction
Speaker 2: to be pointing due.
Speaker 1: North right, uh huh.
Speaker 2: It kind of wobbles around a lot, right, as all
Speaker 2: these little eddies and currents going on inside interact. Sometimes
Speaker 2: they'll line up with the spin axis of the Earth,
Speaker 2: and sometimes they don't. And that's happening on the scale
Speaker 2: of hundreds of years. It's like a tug of war
Speaker 2: where the pole of the magnetic field of the Earth
Speaker 2: is just migrating around.
Speaker 1: Yes, if you look up pictures of where the magnetic
Speaker 1: north pole has been where scientists think it may go next,
Speaker 1: it's not a smooth path. It looks like the path
Speaker 1: a drunk elf would take if they had too much echnogy.
Speaker 1: And it gets even wilder. Scientists believe that in the past,
Speaker 1: the magnetic field of the Earth has even flipped, it
Speaker 1: has turned completely around to the point where the north
Speaker 1: pole was actually in the south pole of the Earth.
Speaker 1: That would be a huge move for Santa Claus. So
Speaker 1: when we come back, we'll talk about why this happened,
Speaker 1: how we know it happened, and whether we can tell
Speaker 1: if it's going to happen again. So ho ho, hold on,
Speaker 1: don't go anywhere, We'll be right back. Hey, welcome back.
Speaker 1: We're talking about whether the North pole is changing, and
Speaker 1: so far we've learned that it's totally changing. The spin
Speaker 1: ax of the Earth is changing in like three different ways,
Speaker 1: and the magnetic north pole of to Earth is also changing.
Speaker 1: It's meandering around worse than a drunk elf today after Christmas.
Speaker 1: In fact, scientists believe that the magnetic north pole of
Speaker 1: the Earth can even switch and flip upside down, and
Speaker 1: that this has happened several times in the history of
Speaker 1: the Earth.
Speaker 2: Yeah, So that's where it gets even crazier. Right, So
Speaker 2: we have all of these spinning, rotating fluids and the
Speaker 2: solid core of the Earth. So you have all these
Speaker 2: eddies all interacting with each other and right now all
Speaker 2: kind of lining up where the net magnetic field points
Speaker 2: to the north pole. But because they're all fluid and
Speaker 2: can interact in these weird ways, they can all kind
Speaker 2: of work together and flip, and so sometimes the north
Speaker 2: pole magnetically becomes the South pole. Why and vice versa.
Speaker 1: Yes, the magnetic north pole of the Earth can change
Speaker 1: so much it can even end up in the South pole.
Speaker 1: So your compass would point to Antarctica as being due north.
Speaker 1: And this has not just happened once before. It's happened
Speaker 1: maybe thousands of times in the history of the Earth.
Speaker 2: And that switch between the north pole pointing north and
Speaker 2: the north pole pointing south magnetically has happened roughly every
Speaker 2: five hundred thousand years or so. Sometimes it's longer, sometimes
Speaker 2: it's shorter.
Speaker 1: Okay, you might be wondering how we know this and
Speaker 1: the answer is that there's a record of the Earth's
Speaker 1: magnetic field at the bottom of the ocean. At the
Speaker 1: middle of the oceans, there are enormous seams where the
Speaker 1: Earth's tectonic plates are separating, and as they separate, lava
Speaker 1: comes up, creezes and forms thew c floor. Now, when
Speaker 1: the lava freezes and becomes rock, the metal in the
Speaker 1: rock records the magnetic field at the time the lava froze.
Speaker 1: So if you measure the magnetism of the rocks the
Speaker 1: bottom of the ocean, you'll see bands parallel to the
Speaker 1: seam or ocean ridge where the rocks magnetism points one
Speaker 1: way and then another way, and then another way. And
Speaker 1: from the age of the rocks, scientists can tell that
Speaker 1: this flipping of Earth's magnetic field happens on average about
Speaker 1: every five hundred thousand years or so. Sometimes it happens
Speaker 1: more frequently and sometimes less frequently. The last time it
Speaker 1: happened was almost eight hundred thousand years ago. But here's
Speaker 1: the big mystery. Scientists don't know if the magnetic north
Speaker 1: pole switches to the south pole really quickly or really slowly,
Speaker 1: and what happens in between.
Speaker 2: It's unclear how long it takes the switch from pointing
Speaker 2: north to pointing south. Does it happen in one day
Speaker 2: or does it happen in a couple thousand years?
Speaker 1: We don't know.
Speaker 2: Most estimates are its probably takes a few thousand years,
Speaker 2: But that is a timescale that's difficult to measure on
Speaker 2: the geologic record, right, we can measure hundreds of thousands
Speaker 2: of years. Yeah, that we can measure pretty precisely. When
Speaker 2: you were talking about is it six days or two
Speaker 2: thousand years, like, we can't tell. It's a little tricky
Speaker 2: to tell that precision. That's wild and it's probably a
Speaker 2: little different every time, right, because it's driven by this
Speaker 2: chaotic stirring of the core of the Earth, right, and
Speaker 2: so that's when the Earth's magnetic field will flip, uh huh.
Speaker 2: You'll kind of get this weird period in between where
Speaker 2: the compass would point to all sorts of random directions, right.
Speaker 1: Like there might be a six day or one thousand
Speaker 1: year period where your compass will point to like Panama
Speaker 1: true north of the Earth.
Speaker 2: Yes, because that's where the magnetic field happens to be
Speaker 2: popping out that day. And then from tradition or whatever,
Speaker 2: from the record that we see, it will eventually end
Speaker 2: up where the north pole of your compass would point south,
Speaker 2: and then we'll stay that way, probably for five hundred
Speaker 2: thousand years, and then flip back the other way.
Speaker 1: So the fact that my compass points north now it
Speaker 1: just happens to be like that. Now, at some point
Speaker 1: it's going to change, and it has changed before.
Speaker 2: Yeah, there's a whole history of how this affected early
Speaker 2: navigation when the fourteen hundreds plus, right, especially when you
Speaker 2: live in Europe and you're at pretty high latitudes, that
Speaker 2: little difference matters whether the magnetic north is right on
Speaker 2: the north pole, uh huh. And so this inability to
Speaker 2: actually tell where doe north was really one of the
Speaker 2: things that led the history of exploration of the world
Speaker 2: by the Europeans to be so so kind of random
Speaker 2: in a way where oh, yeah, sometimes we ended up
Speaker 2: in the wrong place and we thought it was somewhere else.
Speaker 1: It's because the magnetic hole moved.
Speaker 2: Yeah, the compass was just not a reliable way to
Speaker 2: navigate perfectly.
Speaker 1: Okay, So that's the Earth's magnetic north pole and it's
Speaker 1: moving all over the place, and the spinning north poole
Speaker 1: of the Earth is also changing. Does this mean Santa
Speaker 1: is doomed to have to keep moving around forever, like
Speaker 1: maybe keep his toy workshop and reindeer stables in trailers. Well,
Speaker 1: it turns out there is a third North pool here
Speaker 1: on Earth, and that's the one defined by our GPS systems.
Speaker 2: A lot of the expeditions in the late eighteen hundreds
Speaker 2: and early nineteen hundreds to the north and south pole
Speaker 2: of the Earth were driven by trying to find where
Speaker 2: the heck this actual magnetic North pole wash. And then
Speaker 2: they got there and realized, oh, it's moving.
Speaker 1: Like I put a flag here last time, it's not
Speaker 1: here anymore.
Speaker 2: Yeah, exactly, And that's part of why. Now we don't
Speaker 2: navigate by compass is, but we navigate with Global Positioning
Speaker 2: satellites right, GPS system. We've created a more reliable navigation
Speaker 2: pole than the magnetic north Oh.
Speaker 1: That's a third pole. Now we have like a GPS
Speaker 1: pole exactly. Yeah.
Speaker 2: Yeah, we have a way to navigate ourselves with respect
Speaker 2: to the GPS and that won't wobble with the Earth.
Speaker 2: It won't with the magnetic field. It's kind of a
Speaker 2: fixed thing that we can reference.
Speaker 1: Okay, great, we can use GPS. Does that mean that
Speaker 1: we finally have a fixed North pole one that doesn't change,
Speaker 1: Not quite.
Speaker 2: It might drift a little over time. The gravity field
Speaker 2: of the Earth is not perfectly symmetric, right, It's not
Speaker 2: the perfect round ball in terms of gravity. The equator
Speaker 2: is a little fatter than the poles because of us spinning.
Speaker 1: You mean the equator has a different body type.
Speaker 2: Yeah, yeah, yes, yes, the equator has a different body type.
Speaker 2: So if you have a satellite that's trying to go
Speaker 2: around the North Pole, uh huh, the equator will cause
Speaker 2: a little gravity that would yank it to be eventually
Speaker 2: be in an equatorial orbit.
Speaker 1: Wait, you mean like our GPS satellite system could be
Speaker 1: kind of drifting or getting wobbled and we might not
Speaker 1: even know it. Yeah.
Speaker 2: Maybe, And there are all sorts of asymmetries. There's this
Speaker 2: big bulge from the spinning of the equator, but then
Speaker 2: there's also just kind of random places that have more
Speaker 2: or less gravity. Huh. And they had something to do
Speaker 2: with the structure of the continents and the structure of
Speaker 2: the mantle and how much density there are in different places.
Speaker 2: So if you're over the Himalayas, the gravity is a
Speaker 2: little different than if you're over Iowa.
Speaker 1: So now we have three poles on Earth. We have
Speaker 1: the spinning axes, the magnetic North Pole, and now we
Speaker 1: have this GPS reference and all three I mean, they're
Speaker 1: all tied together obviously through physics, but they're not necessarily
Speaker 1: the same or staying constant to each other.
Speaker 2: Yeah, over longer pier then we probably care about. But
Speaker 2: if you're trying to navigate a fighter jet by GPS,
Speaker 2: you probably do care about.
Speaker 1: But if you try to fly the same jet in
Speaker 1: one hundred thousand years, who knows if you'll end up
Speaker 1: in the same spot exactly.
Speaker 2: If your instruments haven't updated their internal system.
Speaker 1: You've literally shaken my world. Mad, I feel like I
Speaker 1: can't trust GPS anymore. Like I thought that was the
Speaker 1: gold standard. The Earth might be doing all kinds of
Speaker 1: crazy things inside of this GPS sphere.
Speaker 2: I think we can very slowly, very slowly.
Speaker 1: Well, I think to summarize, like, if you were looking
Speaker 1: for the North Pole, you could look it up in
Speaker 1: three different systems and you could end up in three
Speaker 1: different places.
Speaker 2: Yeah, so the North Pole itself has a little mystery
Speaker 2: around it, right, uh huh. Depending on how you want
Speaker 2: to address it. It could be in a little bit
Speaker 2: different place. So that's why it's a good place for Santa.
Speaker 1: It all makes sense. Santa has a degreen physics and
Speaker 1: planetary science, and he's like, where's the one place on
Speaker 1: Earth where it's going to be extra hard for people
Speaker 1: to find me? The North Pole?
Speaker 2: Exactly, and especially because the North Pole is covered with
Speaker 2: sea ice. Right, uh huh, antarcticle, we have land, we
Speaker 2: have land at the South Pole, but the North Pole
Speaker 2: is ice, so that drifts around too a so, so yeah,
Speaker 2: I think it's it's a safe spot.
Speaker 1: Now does that mean Santa has to move every couple
Speaker 1: of thousand years or do you think he likes the
Speaker 1: drifting part of it, like he's a drifter at heart.
Speaker 2: Yes, Santa's a drifter at heart. Let the elves control
Speaker 2: the GPS system.
Speaker 1: Oh my goodness, you said on a conspiracy theory. Maybe
Speaker 1: in a given year, if kids get a lot of
Speaker 1: GPS based toys, that's Santa trying to cover his tracks.
Speaker 1: Oh yeah, He's like, let them find me. Here's all
Speaker 1: these GPS A little do they know I'm not at
Speaker 1: the GPS North Pole?
Speaker 2: Give them compasses that don't go the wrong no pole, Yeah,
Speaker 2: lead them astray. Yeah, so maybe this whole magnetic North
Speaker 2: Pole migrating so much is just a way of hiding
Speaker 2: the secret location of the workshop. Pretty much darker tone
Speaker 2: to Santa than I've ever heard before.
Speaker 1: Do you think he lived in Antarctica then, like five
Speaker 1: hundred thousand years ago? Yeah?
Speaker 2: Does he migrate with the migration of the magnetic spinpole
Speaker 2: or the physical spin pole?
Speaker 1: He's like, well, I'm just waiting for the time where
Speaker 1: the North Pole points in Panama, and then I'll move
Speaker 1: to Panama in the tropics and live at the beach. Yeah, exactly,
Speaker 1: all right. Well, uh, dear Santa, if you're listening, please
Speaker 1: don't put me on your naughty list or divulging your
Speaker 1: North Pole secrets. But if you do, please don't put
Speaker 1: a piece of coal in my stocking. Instead, leave a magnet.
Speaker 1: I could use it to make a compass that'll work
Speaker 1: for at least a few hundred thousand years. And to
Speaker 1: everyone else, thanks for joining us. Happy holidays for everyone
Speaker 1: here at sign Stuff. See you next time you've been
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