I'm slightly confused about the "north-seeking" pole of a magnet: does it point towards magnetic north, or is it towards geographic north?
I ask because I've been finding different explanations in different places.
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asked Jan 20, 2013 at 3:32
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$\begingroup$ Compasses point roughly toward the geographic north pole, which is near (but not colocated with) the magnetic south pole. $\endgroup$– honeste_vivereCommented Jul 21, 2017 at 13:19
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1$\begingroup$ @honeste_vivere I think you are wrong. I think compasses point toward the magnetic north pole, and I think the geographic north pole is nowhere near the magnetic south pole. $\endgroup$– Tom B.Commented Mar 12, 2018 at 5:22
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4 Answers
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The north-seeking pole always points toward magnetic north, assuming it is only feeling Earth's magnetic field. A magnet has no idea (so to speak) which direction is geographic north.
Any source that tells you that a magnet points geographically north is only as correct as the statement that geographic north and magnetic north are the same direction.
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You must have seen this image of the earth mapped on a globe before, this one shows a satellite orbit:
The axis of the earth's rotation points to the north pole star and navigation calculations use its location on the celestial sphere to define latitude.
Since ancient times people defined north by the polaris star direction. They also noticed that magnets pointed in that direction, too, and named the magnet's pole accordingly, and used compasses for navigation.
We now know how magnetic fields arise , and have observed that there is a difference in the direction between the magnetic and celestial north. In fact the magnetic pole has been moving continuously. The magnetic field of the earth arises from core magnetism and due to fluid mobility changes the magnetic north by kilometers per year.
Earth's north magnetic pole is racing toward Russia at almost 40 miles (64 kilometers) a year due to magnetic changes in the planet's core, new research says.
The core is too deep for scientists to directly detect its magnetic field. But researchers can infer the field's movements by tracking how Earth's magnetic field has been changing at the surface and in space.
Now, newly analyzed data suggest that there's a region of rapidly changing magnetism on the core's surface, possibly being created by a mysterious "plume" of magnetism arising from deeper in the core.
And it's this region that could be pulling the magnetic pole away from its long-time location in northern Canada, said Arnaud Chulliat, a geophysicist at the Institut de Physique du Globe de Paris in France.
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$\begingroup$ The terrestrial magnetic north pole is actually near the southern geographic pole, not the north. The terrestrial field is changing in time, but the direction in your highlighted text is backwards. $\endgroup$ Commented Jul 21, 2017 at 13:10
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A north-seeking pole will point towards the Earth's magnetic north pole. What might have confused you, however, is that Earth's magnetic north pole is itself a south-seeking pole.
Opposite poles of a magnet attract each other, and since Earth's magnetic north pole attracts north-seeking poles, it itself is a south-seeking pole. Vice versa for Earth's south magnetic pole.
The term north-seeking pole comes originally from the fact that in most places on Earth north-seeking poles will point also towards the geographical north pole. This is, however, not exact, since the poles of a magnet will point towards Earth's magnetic poles, and thus in some places on Earth (i.e. certain places on Antarctica and in the Arctic regions) the north-seeking pole might actually point away from the geographical north pole, and vice versa.
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'Magnetic North' is a LOCATION, not the polarity of that location. It is so-named to distinguish it from 'True North'. Since the 'North-Seeking' pole of a compass needle points in that direction, 'Magnet North' (the location) has a south magnetic polarity.
