Where Does The Earth's Magnetic Field Come From?

What causes our planet to generate a magnetic field? What is a magnetic field?!?

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Episode Transcript

Speaker 1 (00:07):
Orry. Did you know that the Earth has a mysterious
invisible field protecting it? What do you mean, like a
like a force field? Yeah, basically it protects us from
cognate rays and space weather. And also it's a crazy radiation.
That's amazing. That's like a that's like Star Wars, right,
like all the spaceships have a force field that protects it.
How do we have this field? It's pretty amazing. It's

(00:29):
the Earth's magnetic field. Actually, what is that? Suddenly less
exciting to use its magnetic than a force field. It's
not very attractive unfortunately. Um no, I mean what do
you mean? It's it's just like the like the North
pole and the South pole. Is that what you mean? Yeah,
the earths magnetic field serves a really important purpose. But

(00:50):
what a lot of people don't know about it is
that it's changing. It might not be around forever. Oh
what hm? I am Ran and I'm Daniel, and welcome

(01:17):
to our podcast. Daniel and Jorge explained the universe, in
which we take everything about the universe and try to
make sure it makes sense to you. Things in the
sky and things under our feet. That's right, all the
positive things, all the negative things in the universe, all
the north things and all the South things. That's right.
Today on the program, we're going to ask the question

(01:41):
what's the source of the Earth's magnetic field? Like why
is the Earth a huge cosmic magnet? Right? Like that's
crazy to think about, like that that's basically what we are.
We're just the giant flying fridge magnet. That's right, And
the Earth is a huge magnet. It's really powerful. Is
that this huge, single magnetic field envelops the entire Earth.

(02:03):
It protects us from radiation, allows us to navigate, Like
where does it come from? Why does it exist? Are
we lucky to have one? Does every planet have one?
Where does it come from? Can we turn it off?
I have so many questions, and it's super important because
without the Earth's magnetic field, we would literally be toast, right,
Like we would just get burned to a crisp? Is

(02:24):
that a technically accurate use of the word literally? Like
would you turn into toast? Like? Could I spread butter
on you and eating for breakfast? Uh? Dina, depends on
what do you like. I'm not sure I'm into toasted
Jorge for breakfast. But yeah, without the magnetic field, there
would be a huge amount of radiation that just bombards us.

(02:46):
As we said before, the magnetic field bends the path
of charged particles. It deflects them, so it doesn't like
stop them. It's not like a force field where it
goes when it gets fizzled out or anything. It just
bends them. But if a charged particles moving really fast,
then all you need to do is deflect it and
it will go somewhere else instead of write into your
brain and give you cancer. Right, And it's not just
like a little bit of charged particles or it's a

(03:09):
lot like the field is doing a lot right now. Yeah,
it does a lot of work. Without it, we wouldn't
have an atmosphere, right, we would. We wouldn't be able
to breathe, we would, Really, the earth wouldn't be the same. Yeah,
it does a lot of heavy lifting every day, and
most people, most people just ignore it. You know, most
people aren't even aware they're aware of everything that's being
done for them by the magnetic field. Right. Ever, ever,

(03:30):
wonder if it feels resentful, if it's like, man, nobody
ever gives me props. I'm doing all this work here.
Everybody just takes me for granted, right, it should just
turn itself off for a few days just to teach
us a lesson. Yeah, yeah, I think people do take
it for granted. You know, it's kind of like nobody
ever pays attention to to which way is north. You
just think that it's always going to point to the

(03:51):
same direction. But it's not right exactly. And we've had
a magnetic field for billions of years. As far as
we know, the Earth's magnetic fields formed pretty soon after
the planet came to be. Okay, yeah, that's that's something
I didn't know. And in fact, let's let's talk about
a couple of things that maybe people don't know about
the magnetic field. Some interesting facts about the magnetic field

(04:14):
is that it's not perfectly aligned with our rotational access.
That's that's pretty surprising to me. Yeah, it's off by
about eleven degrees. Right. Yeah. The Earth, it's like it
has two north poles. Right, one is the one it
spins around. Right, the whole Earth is spinning. Right, Who
gives us day and night as the Earth turns towards

(04:35):
and away from the Sun. Yeah, we're spinning. The Earth
is spinning. And so if you put a line through
around where it's spinning, you would get one north pole.
But you're saying the magnetic north Pole is not aligned
with that one. That's right, it's not exactly aligned with this.
So if you were standing on the rotational north pole,
the point around which the Earth is spinning, right, and

(04:58):
you looked at a compass would point away from that place,
it would say, Nope, you're not at the magnetic north Pole.
Because the wait, so then where the Santa Claus live?
Does he live in the rotational north Pole or the
magnetic north Pole or does he have two houses? That's
a big secret. I think we should save that for
an entire other podcast. So the magnetic north Pole is

(05:20):
different from the rotational north Pole. They're different by eleven degrees.
And remember it's like three sixty degrees all the way
around the circle. Eleven degrees. So it's not a big difference.
If you're in the US or in South America or whatever,
or in Asia. You can mostly use a compass. It's
going to point pretty close to the top of the
Earth as we think about it rotationally, but not exactly. Wow,

(05:42):
it's a big deal if you're in the north Pole, right,
I mean eleven degrees must be like a thousand miles
or something. Yeah, as you get closer and closer to
the North Pole, becomes a bigger and bigger deal. Right,
So that if you're standing on with the line that
Earth rotates around, it's going to be kind of a
big deal that the North Pole is far from there.
But if you're far away from like most people are,
most of our listeners are, then it's not really an issue.

(06:03):
But I think it raises the interesting question like why
aren't they aligned? Where does the magnetic field come from? Right,
like a big bar magnet inside the Earth that's got
like knocked over and tilted. Is it something totally different?
That's what I think. It's it's quite fascinating. Um, so
it's three point four billion years old, meaning that before
three point four billion years we didn't have a magnetic field. Yeah,

(06:24):
that's right. And it's basically because earlier than that, the
Earth was just a hot ball of nasty magma and
nothing was really organized. So before that you didn't really
have all these structures we needed to generate the magnetic field,
and so it's just like a yeah, it's just a
ball of lava in space, basically a giant level lamp.

(06:45):
Exactly a hot drop of rock. We've got from fridge
magnet to level lamp. I guess we'll get in more
into how that works. Um, But this is this is
an interesting semantic point, which is that the north pole,
but we call the north pole, is actually the magnetic
south pole. Yeah. It's one of these things about definitions, right.

(07:05):
It's like when they discovered electricity. You know, they defined
positive negative currents, and it turns out that electrons have
negative charge. Right, it's just a definitional thing. But when
they first figured all this out, they define north as
you know, whichever side of the magnet points towards the
Earth's north pole. But that actually makes it the south right,

(07:26):
because the southern the south pole of a magnet will
point towards the north pole of another magnet, right, And
so that's just a definitional thing. But it's kind of funny.
So if you're holding onto your compass, the magnetic north
pole of your compass points of course towards the Earth
north pole. That means Earth north pole is magnetically south right,
because the north pole of your compass is attracted to it.

(07:49):
So we should change the name or change the laws
of physics, which one should we do? First? Let's come
up with better names, right, like not north and south,
but like apples and oranges, or h I lift four
blocks apple of here? Is that? Is that a general idea?
I always thought it was weird that it was north
and south. I mean, I understand where it comes from.

(08:10):
It comes from the geographical question where are we in
the Earth rotating and stuff? But from a physics point
of view, you know, we like to think of these
things is like positive and negative. Right. All the other
charges we think about, like electric charge and gravitational charge
or weak force charge, we all think about those in
terms of positive negative numbers. So north and South is

(08:30):
sort of archaic. So if I had to redo it
all over again, I would just define one of them
is positive and one of them is negative. It's like
a big magnetic battery. And then we wouldn't be so
concerned about the North Pole not being aligned with the
rotational North Pole. Yeah, we would probably have a big
political question like would you rather have the North pool
be positive or negative? Right? Everybody, part of everybody probably
wants to be positive. In the southern hemisphere would argue

(08:53):
we should be positive your guys are so negative up
there here being colonial exactly. That's right, that's right. Okay,
So those are some pretty cool facts about the Earth's
magnetic field. Um, but now let's talk about what what
what's the source of it? How? How how come we
have a magnetic field and other planets? Stone and I

(09:15):
think a really important clue there is the fact that
the magnetic field is not static. It's not just like,
here's the magnetic field. It's always been this way, it's
always gonna be this way. A big clue that the
source of the Earth's magnetic field is something weird and
interesting is that the magnetic field is changing. You know
that the magnetic field is moving. It's moving quite a bit,

(09:37):
and it's also getting weaker, Like the magnetic field was
much much stronger when the Romans were in charge of
the world than it is today really and even years ago,
a couple of thousand years and um, eventually it might
even flip, right, it might be that positive becomes negative,
north becomes south. And so that's quite interesting, right, and

(09:59):
tell is that there's something really interesting going on making
that magnetic field. So let's dig into that. Yeah, let's
let's talk about that um. But we were wondering how
many people out there knew or had this idea that
the magnetic field is not something that's given in on Earth.
How many people out there knew what's the source of
the Earth's magnetic field? Yeah? So I went around and

(10:20):
I asked a bunch of unsuspecting undergrads that you see Irvine,
and said, what do you think about this question? So
before you hear their answers, think to yourself, do you
know where the Earth's magnetic field comes from? Could you
explain it? If you had to build a planet from scratch,
how would you make sure it had a magnetic field? Yeah?
Would you put just a bunch of fridge magnets in
the middle, like a bunch of fridge magnets. Well, here's

(10:44):
what people had to say. Something to do with the core.
It's across gravity that atmosphere a little okay, gravity, Um,
I assume it's the rotation um of the Earth's core.
Is it the core? The core, the Pole's north pole? Softhpore?

(11:06):
Al Right, pretty I think there's a pretty good credit
to those students at the University of California, Irvine. Um,
pretty good, said gravity, it's always gravity. It turns out,
actually they're not entirely wrong. Gravity as always plays a role.
My favorite answer was the one that said the north

(11:26):
pole in this south pole that gives the magnetic field.
It's like, cool, cool, good, complete, complete answer without actually
revealing any information. Yeah, and not making fun of these
people of course, you know, I put them on the
spot answer random physics question. I'm I'm just impressed that
they were even willing to share their thoughts with me. Yeah,
I know it takes it takes some certain amount of
bravery to talk to you in public, Daniel, I don't

(11:51):
even know how to respond to that one. Um. No.
I usually try to avoid talking to myself in public
also for that same reason. Yeah, it's not it's frowned upon.
Um But No, what I mean is a lot of
people answer they need to have something to do with
the Earth's core, something about the core and the magma
and the crust, something about the something going on inside

(12:13):
the Earth itself. Yeah. Yeah, And it's like thinking about
the Earth is a big machine, right, which is kind
of crazy because you walk along the surface of the
Earth and you think of it just as a big rock, right,
But underneath there are powerful forces and crazy things happening,
and all that is happening in order so that you
can have a magnetic field. So it's I'm just glad
that people are aware of all the work the Earth

(12:34):
is doing for us. Yeah, there's there's stuff happening inside
the Earth, right, like it's an active machine. It's an
active device. Yeah. Absolutely, it's like a boiling kettle of
magma and crazy stuff is happening in there. And if
it wasn't, we wouldn't have a magnetic field. So we're
glad to have sort of a young hot planet. Yeah,
well let's get into it, um, but first let's take

(12:56):
a quick break. I'm an engineer, and I have to
admit that I don't really understand how magnets work. So
I thought, maybe, welcome to the podcast. He came to

(13:16):
the right place. This sounds like a great episode. I'll
tune in, UM, But let's take a step back maybe,
and then talk about the magnets in general. Yeah, magnets
are really pretty amazing. They're one of my favorite things
because they're like physics that you can see with the
naked eye. Right, you can see a fridge magnet um
sticking to the wall, you can even get these things
to push away from each other without touching. It's like

(13:39):
the first sign of a force that you can really
play with and identify with. It's it almost looks like magic.
Of course it's not because we understand it, but it
has something in common with it. Right, it's powerful, it's visceral,
it's physical. It's right there in front of you. It's
a lot of fun because most things don't act like magnets, right, Like,
most things don't stick to the wall. If you put

(13:59):
them there, those things don't push against you without any
direct line of connection. Right, It's so it's weird. I
don't know how many things have you tried. I've thrown
a lot of different things at the wall, and a
good number of them actually stick. You know, spaghetti sticks
to the wall, sticks to the wall, lasagna sticks to
the wall, Lots of different kind of foods. Don't you
have young kids? You should be aware of how many
things do actually stick to the wall. Once again, I'll

(14:22):
i'll them, I'll decline your invitation to visit your house
just where you know, all rubber clothing. It's no big deal.
I mean, just we just hose off after dinner. Um, no,
you're right, and not everything is a magnet, right, and
so not everything sticks to sticks to things, and so
let's let's talk about that a little bit. How do
you how does something become a magnet? What makes something
a magnet and something else not a magnet? Right? The

(14:45):
amazing thing is that it's all about electrons. Okay, like
the kind of magnet you're familiar with, you know, a
fridge magnet and normal like a piece of metal that
has become magnetized that sticks to something. How does that work? Well?
The way that it becomes a magnet is because it
has bill ends of tiny little magnets inside of it.
Each electron has something we call quantum spin, and it's

(15:07):
not actually spinning around or doing anything physical. It's a
quantum mechanical property we call its spin, and it generates
a little magnetic field. So this electron does this weird
thing and it generates a very tiny magnets. So every
electrons is like a little magnet. So it's not actually spinning.
Physicists of just are spinning it as if it was spinning.

(15:28):
That's right, it's physics spin. Yeah. We use the word
spin because the thing it does, the quantum spin has
a lot of similarity with physical spin. Like the mathematics
we used to describe physical spin angular momentum. A lot
of that mathematics can be copied over and applied directly
to quantum spin. And that's what makes this compelling as

(15:49):
a as a concept, and we should have a whole
episode about what is quantum spin because it's fascinating. But
but the point is that each electron itself is like
a magnet. It's like a really maney little magnet with
a with a field as its own little magnetic field.
And in some kinds of materials, the way the electrons
are organized in their shells, etcetera. Gives you an overall

(16:12):
magnetic field for the atom. Okay, and some of them
that they don't just cancel out you get nothing um
and some of them you do get little magnets for
the atom. And then in some of those atoms they
like to organize in a way so all the magnetic
fields are aligned. So, for example, in iron and a
lot of metals have these properties that you can align
all the little magnetic fields of the atoms so they

(16:33):
point in the same way. So when you have a
piece of magnet like a chunk of metal that sticks
to your fridge. The reason it has a magnetic field
is because all those tiny little magnetic fields are all
going in the same direction, so they add up to
kind of a big magnetic field. You have another piece
of metal, it's not magnetized, and all they're just sort
of scrambled. They're all in different directions. So there are

(16:55):
magnetic fields in there, but they're all just sort of
canceling each other out. And it's not just metals. I
mean you and I and the chair, riman, this wooden chair,
theman it's it also has these billions of tiny little magnets.
But the problem is they're not all pointing in the
same directions, so they all cancel out, and so overall
it's not a magnetic thing. Yeah, exactly. You have to
be magnetic. You need to have these little magnetic fields,

(17:16):
and you have to have a structure where the substance
likes to organize in a way so they all point
in the same direction. Um, so we're all magnetic. We
all have magnetic personalities. You want me to tell you
you're a magnetic dude, You're a magnetic dude. That's about um.
And that's how something can become a magnet also, right,
Like you have a normal piece of metal and it

(17:37):
sits next to a magnet for a long time, Right,
how does that become a magnet? Well, the first magnet
is aligning all the little magnets in the other one.
It's pushing them in the same direction, so eventually becomes
a magnet itself. But let's um, let's see if we
can get into maybe a little bit more so, what
does it mean that each electron is like a little magnet? Why?

(18:00):
White White said? Why does the electron have a field?
You know, like white white and it white, it a
pointed field. Well, there's a very close connection between electricity
and magnetism, right. In fact, we think of them as
one theory electromagnetism, and there's a lot of connections, like
anytime you get electricity moving in a circle, that makes

(18:21):
a magnetic field, okay, and and the other it works
in the other direction to any magnetic field that changes
in time will generate electric currents. So we think of
these things electricity and magnetism is sort of separate. Turns
out they're really closely connected. They're really just two sides
of the same coin. And That's why it's not really
surprising that the electron, which is like the most basic

(18:42):
charged particle we have, could generate electric fields because in
the end, it's a charge and it's not physically spinning,
but it has quantum spin, and so you can think
of it as like having a small quantum magnetic field.
It really is a quantum mechanical effect, Like every fridge
magnet is a quantum mechanical effect. Wow. So it's just
something kind of embedded in the laws of the universe,

(19:05):
is that whenever you have something with charge, like an electron,
is just sort of automatically, by the laws of physics,
associated with a magnetic field. Yeah, charges plus motion gives
you magnetic fields. In this case, the motion is the
quantum spin, right, And that's how you can make a
non permanent magnet, right, Like that's how you make electromagnets exactly.

(19:26):
So there's a little electrons, they spin and they make
their own little magnetic field. But you can also do
something else with them, is that you can move them
in a circle, right, make a loop of wire and
pass electricity through it, and it generates a magnetic field. Why, well,
that's just one of the Maxwell's equations. That's one of
the laws of electricity and magneticism that currents moving in
a circle will generate a magnetic field, because magnetic fields

(19:50):
and currents are very closely connected. As I said before,
there's just really two parts of the same thing. This
is pervasive quantum field that that fills the universe. Right
that let's just up into the electro magnetism at any
point and moving charges through it will generate the magnetic field, right.
And it's so it's kind of like if you take
a bunch of electrons and you get them to go

(20:11):
and move in a circle, they all sort of aligne
and add up to create all of their little magnetic
fields to create a big magnetic field in the center
of the circle. No, it's not their personal magnetic fields
like the ones that come from their quantum spin. It's
the fact that they're moving in a circle generates the
magnetic field in the center. So they still have their

(20:32):
own little fields from their quantum spin, but it's their
motion in a circle. The current moving in a circle
will generate a magnetic field as well. But why um?
But why the deep question? Man? I think the um
there's a technical way to think about that question, which is,
look at the equations that describe it. And those equations

(20:55):
have symmetry in them. They're called Maxwell's equations. You can
google them and look at them, and they show you
that electric fields and magnetic fields really are connected. But
I think the intuitive way to think about it is
just as part of one, right it. Don't think that
moving currents generates magnetic fields, like this one kind of
thing generates this other kind of thing. Just think of

(21:15):
them as part of one combined thing. Right. There's a
close connection between electric fields and magnetic fields, and a
fascinating insight comes from thinking about how electric and magnetic
fields change if you look at them from different velocities. Like,
if you have an electron at rest, it mostly gives
you an electric field. Right, It's a very small magnetic
field because of its quantum Spinlet's ignore that for now.

(21:36):
But somebody else driving by, they see that electron not
at rest, they see it is moving, right, and moving
charges give magnetic fields. So if you're at rest with
respect to the electron, you mostly see it an electric field.
If you're in motion with respect to the electron, you
see an electric field and a magnetic field. This really
is a clue that the two are different parts of

(21:56):
the same thing, and you see different parts of it
if you're moving at different speeds, so they really can't
be separated. They're really just two parts of the same beast. Oh. Okay,
so that's magnets um there. They can either be permanent,
meaning that it's just the electrons inside of the material
adding up to make a big magnetic field, or you

(22:20):
can also make it field by moving electrons around in
a circle. Okay, So so the Earth is which of
the two? Is the Earth a permanent magnet or is
it like a like an electric motor. Well, it's a
great question. For a while, we didn't know because it
could have been that the Earth had basically a bunch
of permanent magnets buried in it, right, because you know,
there is this crust and it's got a lot of rock,

(22:40):
and a lot of those rocks are metallic, and you
might imagine maybe there's just a bunch of magnets and
they all got a line somehow. Right. Yeah, that wouldn't
make sense, right, it would make some sense, right, You
can imagine that happening, and then the Sun has a
big magnetic field, so you can imagine maybe the Sun
magnetized the Earth. And well, before we go too far
into that crazy speculation, the answer is no, the Earth
is not permanent magnet um and we know that because

(23:03):
the earth magnetic field seems to penetrate from the core right,
not from the crust, and also because it's changing. It's
not static. It's not the same all the time, and
a permanent magnet by definition, it would be permanent right
if it was. If it came from a bunch of
buried magnets inside the Earth, then those wouldn't be changing.
In fact, we do see the earth magnetic field changing.
So how fast is it changing? Is it changing by

(23:26):
the hour or by the one thousand years? It's more
on the thousands of years schedule, but we don't really know. Um.
The amazing thing is that we can see the history
of the Earth's magnetic field. And the way we can
do that is that we um we look at magnets
being generated over time on the sea floor. So there's
these like volcanoes that spit up magma and lava and

(23:48):
stuff on the floor of the ocean, and what happens
when they come up the floor of the ocean is
of course they cool very quickly because you know all
that cold water and lava, and it cools very quickly.
But the lava is sometimes magnetic, right, has a bunch
of little magnets in it, And so what happens before
they cool is they get aligned with the Earth's magnetic
field and then they get frozen. So each of those

(24:10):
rocks is like a picture of the strength and the
direction of the magnetic field when it was formed. I
was about to ask you how we know have we
been measuring the magnetic field in our history books, But
we don't have to it. It's kind of embedded in
the Earth itself. The history of that it's really amazing.
And because the volcanoes underwater just continuously spew this stuff out,

(24:33):
we have this like unbroken record of the strength and
the direction of the earth magnetic field over thousands and
thousands and millions of years. And that's the crazy thing
is that not only is the earth magnetic field changing,
like it's getting weaker and it's sliding off the north
pole a little bit. It used to point the other way. What, yeah,

(24:54):
like one eight degrees. Yeah, exactly, like if you jumped
into a time machine with a compass. Today and went
back eight hundred thousand years the compass with point in
the other direction. Okay, so there's stuff going on and
it's changing, which means that the Earth is not a
permanent magnet. We're not a giant fridge magnet floating through space. Um,
so what's going on in there? What's what's what's causing

(25:15):
the field? Then inside the Earth? Yeah, well it's kind
of a mess, um. But you know, the one option
is permanent magnets. If it's not, that has to be
a current, right. You need some sort of charges moving
in a circle to generate a magnetic field. So what
could be doing that. It's not like somebody built a
huge machine made of wires down under the ground, right. Instead,
what we have a sort of basic picture of what's

(25:36):
inside the Earth is you have the crust which we're
standing on. Under that, there's a big liquid layer of
various rocks and metals, and then there's a solid core, right,
and that liquid layer is sloshing around. There's a lot
of heat that's coming up from the gravitation of pressure
and from the radiation of all the crazy stuff inside
the Earth. It's keeping that sort of bubbling and frothing

(25:57):
it's like a big soup of liquid little and basically
the currents in that soup of liquid metal are what's
generating the magnetic field. So all those electrons in that
soup moving around in a circle is what creates the
earth magnetic field. Yeah, if you take something that can
conduct electricity, like iron, and you melt it down right

(26:18):
and you slosh it around in a circle, you'll be
generating little magnetic fields because you have electrons and they're
moving in a circle. Right. And it's a little bit
more complicated than that, because it's not like the liquid
inside the Earth is just slowly moving in a circle
and that generates the magnetic field. It's much more turbulent
than that. Right. This convection going on is it's things
that are dense fall and things that are light bubble

(26:40):
up to the top and that's making all of this swirling.
And there's this cool effect called a dynamo. And what
happens is you get a little magnetic field from some
initial swirling, and because electricity and magnetism are so closely connected,
that magnetic field will push electrons around. Right. Like we said,
the magnetic field of the Earth deflects charged particles. Right. Well,

(27:01):
when you get a magnetic field started in the Earth,
it builds on itself because the motion of the electrons
gives you a magnetic field. That magnetic field pushes those
electrons around even more, which gives you more magnetic field.
So it's sort of a feedback effect, like a perpetual
motion machine, kind of like feedback. Yeah. The source of
energy is that you have this all this heat that's

(27:24):
coming from the gravitational pressure the Earth being squeezed by
its own stuff and the radiation. So it's not like
a perpetual motion machine because it's constantly being fed energy, right,
So it's more like a like a bubbling cauldron of
stuff right that generates these magnetic fields, and and its
motion is sort of related to the Earth's rotation, right,
I mean it's um like the Earth spinning is kind

(27:45):
of what creates these currents going in a certain direction,
which is why the magnetic field is sort of aligned
with this rotational access of the Earth. Yeah, exactly, these
currents are the Earth movie relative to its liquid core. Right.
If you ever held like a you know, a ball
that has liquid inside of it, you know they don't

(28:07):
roll normally, right, If you have a ball half filled
with liquid, you roll across your garage floor, it's gonna
go all wonky and be really unpredictable, right, And if
you spin it, similar things happen, and so it creates
crazy currents inside of it. And so this this is
like it's hot and it's bubbling and it's spinning. So
you definitely get lots of really complex fluid dynamics going
on inside there. But it's related to the spinning, but

(28:29):
it's not completely dependent on the spinning, which is why
it's the two axes are not aligned, that's right, Yeah,
but they're definitely related, right, definitely related. But you know
what's generating the magnetic field? The short version is that
it's you know, spinning hot liquids inside the earth, spinning
magnetic conducting liquids inside the Earth are generating our magnetic field,

(28:49):
which is crazy, right. Yeah, the Earth is is hot,
it's magnetic, it's attractive. It's amazing to me that it's
stable at all. You know that that would like not
just be pointing. And also it's a in the directions,
you know, like you watch a pot of water bubble, right,
and it's crazy, it's going crazy all the time is
this direction in that direction? Then somehow the Earth's magnetic
field is surprisingly stable, given given all the craziness that's

(29:12):
happening under our feet. Well, let's talk about that, but
first let's take a quick break. Let's get into that
is it stable? Because you said earlier that it it

(29:33):
flipped a long time ago and it's moving over thousands
of years, that that doesn't seem super stable. Our magnetic
field is remarkably stable compared to others, Like the magnetic
field of the Sun. It flips direction every eleven years
very regularly. What. Yeah, the Sun's magnetic field like has
a huge impact on the solar system like where to

(29:54):
charge particles go and how does the solar wind blow
and all this kind of stuff, and every eleven years
it just flips flips. What causes it to flip? I
mean on Earth, what causes our field to flip? We
don't really understand it, um, But the short version is
that it's a big hot mess and it's sort of unstable,
and so you know, it's mostly supporting itself and you

(30:14):
get a feedback effect. But these things can be crazy.
It's like when you roll that half filled ball across
your garage floor. Sometimes it mostly roll straight. Sometimes it
does a crazy loop. And so if one little random
thing happens, it can push it sort of off course.
That can build on itself and feedback in the wrong direction.
So these are instabilities from equilibrium and when that happened.

(30:36):
Once that happens, it can very quickly go off course.
Imagine you're like driving your car down the freeway at
ninety you know everything's going fine and and your and
your and it's all good. Suddenly a tire pops right
and you're flipping over, or you veer, you know, your
kid makes the noise in the back seat, and you
pull your hand on the steering wheel a little bit,
you start going in the wrong direction. It's suddenly very

(30:56):
hard to get back on track driving smoothly right. It's
sort of like that with the magnetic field. One little
random effect, one little random occurrence can sort of build
on itself and make things go crazy, and eventually things
can even flip over and go the other direction. It's
kind of like a chaotic system. Absolutely, absolutely, that's the word.
It's a chaotic system. So what happens when it flips

(31:18):
is it is does it just happen overnight, Like one day,
who I'll see my compass point in one way and
then suddenly else seet flip pointed the other way. Or
does it build over hundreds of years? Well, Um, the
fossil record we have is not very precise down to
like them the minute or the year or something. Um.
But as far as we can tell, it doesn't happen overnight.
You know, these things are all geological time scales, so

(31:40):
it takes a little while. Um. But the interesting thing
about the earth magnetic field is that the periods of
flipping are not predictable as far as we can tell. Like,
sometimes it will flip, like you know, every hundred thousand
years it will flip, and sometimes it'll go fifty million
years without flipping. But does it flip one eight degrees
or can it flip sideways? It's flips usually so that

(32:03):
the north pole is at your house yet Clause, I've
always thought you kind of look like Santa Claus. Yeah,
the Chinese Panamanian version of Santa Claus. Many people don't
have the actual historical origin of Santa Claus everything, like
everything else, we've just stole in our culture. Um. No,

(32:25):
it's it's um. There are too, more stable set situations,
and one is um, you know, the north pole, on
the Earth's rotational north pole, and the other one is
on the Earth's rotational south pole. I see. Those are
the stable coming because they sort of aligned with the
spinning of the Earth. Exactly. It can't just be random
because the spinning of the Earth does play a role
in generating those currents and maintaining them. Oh, I see,

(32:48):
but maybe there's a few thousand years in between where
it's sort of wandering around the Earth. Yeah, exactly, and
it can drift, and that's what's actually happening right now. Like,
right now, the Earth's magnetic pole is moving forty kilometers
per year. Forty kilometers. Wow. Yet I was stunned. It's fast, right,
I mean you might think, well, forty kilometers per years

(33:10):
not a lot of meters per second, and that's true,
but you know that adds up over a bunch of years.
And not only that, but it's getting weaker, right, It's
getting weaker every year by several Percentum. We don't know
what's going to happen because we can't predict these things,
but you know, if you do sort of like a
trivial straight line trajectory, then it's getting weaker and weaker
and it might eventually flip. You know, we we have

(33:32):
records from earlier times when humanity was around, and like
the Romans, they had a magnetic field that was twice
as strong as ours is. So it's definitely active. It's
not like it's right now just hanging out like things
are happening. The magnetic field and the thousand years could
be different dramatically than it is today. So if I
took just like a regular compass and I sat it
on my table, and I filmed it for you know,

(33:55):
a couple of years, and then I spit up the
video fast forward, I would to see it. You might
see it drift a little bit. Yeah, yeah, if you
wait long enough and you're far far enough north, then yeah,
you could see the compass drift a little bit exactly.
And you know, I wonder about things like animals. You know,
a lot of animals use the magnetic fields for navigation. Right.
We've recently figured out that, like birds, some of them
can see magnetic fields and use them to help figure

(34:18):
out where to go. I wonder if that like totally
screws up the birds. Yeah, well forty kilometers a year,
and it's it's a lot. I mean, that means Santa
Claus every year has to move forty kilometers, has to
pack everything up the whole factory. Moving sucks, so it's
such a drag. And if you've got all that stuff
in the workshop, at least he's got a little little
elves to help him, right, Yeah, maybe that's why he

(34:39):
has it helves, you know, just to help him move. Originally,
that's why he contracted the elves. But I mean it's
not it's not a little bit. It's forty kilometers. Every
year you have to pick up move forty kilometers and
that's where the new north pole would be, the magnetic pole.
Yeah exactly, Yeah, okay, And you said it's getting weaker,
Yeah exactly, it's getting weaker. Also, it's like just not

(35:00):
as strong. Um thousand years ago it was stronger than
it is today, and every year it's getting a little weaker.
And we don't know what's going to happen. Next year.
It might like drift back towards the rotational north pole
and get stronger. Right, these things are unpredictable. But there
are a bunch of people working on this and they
have really complex computer simulations that describe like all of

(35:20):
the physics we think is happening inside the Earth and um,
until recently those simulations didn't agree with what we were seeing.
But now they're more sophisticated and they can model all
the complexities and the simulations are pretty good, so we
think we have some understanding of all the crazy effects
that are happening in there. And they even do predict
things like the earth magnetic field flipping. They can't specifically

(35:42):
predict when our magnetic field is going to flip, but
you know, they have a computer model in which sometimes
they see it flip. Right, But this idea that it's
protecting us and keeping our atmosphere in place, we don't
need to worry about that, right, Like it's getting weaker,
but it's not going away. Should we worry? Sort of
a deeper philosophical question, you know, in general, in general,

(36:05):
should we worried? My Jewish grandmother says, yes, Um, I
think we're not likely to lose our magnetic field. Right.
Look at a planet like Mars, right, Mars used to
have magnetic field, but it doesn't anymore, and the reason
is that it's insides have gone quiet, right, it's cooled,
and it no longer has like a lot of crazy

(36:26):
stuff happening on its inside. So it lost its magnetic field.
That's not likely to happen to the Earth anytime soon.
And so we're gonna have some sort of magnetic field
protecting us from space. It may be stronger, maybe weaker,
may point in another direction, but we're still we're likely
to still keep this force field. Okay, so I don't
need to stockbell on sun block or refrigerator magnets silver panels.

(36:48):
I wonder if how how many refrigerator magnets would take
to protect yourself from cosmic rays? All those a tinfoil
had people a little do they know it's fridge magnets.
You gotta put them on. He put them on your head.
We're gonna spawn a whole generation of refrigerator magnet hat people. Now, Yeah,
we should sell those in our store. Oh my gosh,
let's sell refrigerator magnet hats. Force field had personal force field,

(37:13):
had the well and and actually would be real science.
It really does generate a force field, and it really
does deflect radiation. Yeah, oh my gosh, somebody get the
lawyers on that. Yeah, we need to open Daniel and
Jorhe dot com slash store, ap slash Crazy Science Protection Store. Alright, well, um,

(37:42):
let's take a step back here. I mean, it's pretty
amazing to think that our planet is currently in our
Solar system. It's special because we have this magnetic field
and and without it there wouldn't really be any life
on it, that's right. But you know a lot of
planets have bangnetic fields. Jupiter has one, all the big
gas giants have one. Basically any planet that's rotating and

(38:02):
has stuff going on inside it has a magnetic field.
So we expect that a lot of rocky planets out
there probably have met magnetic fields. And that's absolutely essential.
Mars is sort of unusual, right, Mars and Venus also
doesn't happen, right, Yeah, that's what I mean. Yeah, And
and we have and it helps us have an atmosphere
in life, and so we really wouldn't be here without

(38:23):
the Earth magnetic field. No props to the magnetic field, man,
it's absolutely essential. Yeah, And without it would blow away
our atmosphere, right, The solar wind wouldn't be deflected, it
would rob us of atmosphere slowly over time, like what
happened to Mars. So it's definitely very important. And you know,
we still have a lot of learned to learn about
the sort of extra planetary magnetic fields. Like I would

(38:44):
love to understand why the Sun's magnetic field flips so
regularly and so dramatically every eleven years. It's a mystery.
And you know, we even have moons out there in
the Solar System with magnetic fields. Our moon doesn't seem
to have one because it's basically a lump of rock.
It might have had one earlier in its lifetime. Um,
but like Ganymede, is big enough to have like stuff
going on inside it to have its own magnetic field.

(39:06):
So it's sort of like a property of a planet
when he gets like big enough, you know, exactly when
you're a real planet, you have a magnetic field. Yeah,
it's amazing to think that at the scale the Solar System,
things are kind of chaotic, right, and the Solar System
is changing all the time, and it's doing crazy stuff,
it's flipping its fields. It's yeah, the Earth is not
just a rock, right, it's a it's like a really

(39:27):
big machine doing crazy stuff out there in space for us.
All right, I hope you found that an attractive topic
with two magnetic personalities current importance. I hope that charged
you up for your day. Yeah, and maybe next time
you go out there and you think about the fact
that you're swimming in this amazing and unpredictable field that

(39:52):
is protecting the earth. Yeah, so go out there and
get the fields for your magnetic field. Thanks for joining us,
so your next night. If you still have a question
after listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us

(40:14):
at Facebook, Twitter, and Instagram at Daniel and Jorge That's
one word, or email us at Feedback at Daniel and
Jorge dot com.