I looked it up on Wikipedia; I’ve tried googling.
The explanations use big words and jargon I don’t understand.
In: 19
The earths magnetic field is shaped like a donut, and the magnetic poles are where an imaginary pencil stuck in the hole in the middle would point straight up. The geomagnetic pole is where it would be if it were a perfectly shaped donut. It’s not a perfect donut though, it’s a little bent and lumpy, so the actual magnetic pole is where the pencil sticks straight up in the real, slightly bent donut.
The Earth spins, this causes day and night. That spin is around an axis is between the geographic poles. The Earth also contains a giant magnet in its liquid core. This magnet defines the magnetic poles.
“Geomagnetic” probably means magnetic, being clear that it’s the overall average of the pole positions. Unlike the rotation, there isn’t a mathematic definition of the magnetic pole positions because the field isn’t perfectly uniform.
Think about it like a giant magnet in the middle of the earth that wiggles around because of everything moving inside earth. The magnetic north pole is exactly where north is on that magnet, and follows the wiggling. While the geomagnetic pole is the middle of all that wiggling, a “close enough” estimate for us to use without changing it every day.
There’s a bunch of different Norths.
True North (also called geodetic, which is what I think you’re referring to) is the place where the earth spins. It’s the axis of the earth. Where the screws in the globe are.
Magnetic north is where the compass points. Magnetic north travels around the True North sort of like a top spins around where you started spinning it.
Magnetic North Pole is where your compass points. Because the Earth’s core (the magnet inside the Earth) moves a bit, the spot your compass points to moves around a bit. Geomagnetic North Pole is the average position of the magnetic north pole.
The earth has three sets of poles.
The geographic poles are the points on exotic opposite ends of the earth defined by the earths rotation. Like the bar that goes through a globe.
The magnetic poles are where your compass will point. They are created by the magnetic dynamo of the earths metallic liquid outer core swirling around. However the field it creates is complex due to various eddys and other material in the earth so neither the north or south magnetic pole are the same as the geographic poles. They move around over time. And they aren’t exactly opposite each other either.
The geomagnetic pole is what the magnetic poles would be if the earths magnetic field could be modeled by an ideal bar magnet. It’s more of an average of the magnetic field and it’s affects over time. It’s a useful model for understanding certain features of the earths overall magnetic field. It also is where we see the auroras, in rings around these theoretical poles. Like the geographic pole these poles are exact opposites.
TLDR:
Geographic – Axis of earths rotation
Magnetic – Where your compass points
Geomagnetic – Around which we see the aurora
The earth has a magnetic field, which is a bit like having a bar magnet skewering the earth.
A compass needle points towards the magnetic north pole of the earth. So, if you stand at the equator, the needle points North. If you stand directly at the magnetic north pole, then the compass needle points directly down towards your feet.
The magnetic south pole is basically the same idea, but it’s where a compass needle points directly up away from the earth.
There’s one slight catch. The magnetic south pole and magnetic north pole don’t actually line up with the centre of the earth – the magnetic field is a bit wonky.
The geomagnetic north and south poles are where the imaginary bar magnet skewer would be, if it went through the centre of the earth and got as close as possible to the magnetic north and magnetic south poles.
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