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The magnetic north pole, geographic north pole (centre of the axis of rotation), and solar-system-north are all approximately aligned, and aurora borealis is visible at the north and south poles whichever one you mean.

If the earth was rotated to change its axis of rotation (perhaps so that geographic north points directly at the sun at a certain time of year), would aurora still be visible at the geographic north pole, or somewhere else?

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    $\begingroup$ Could quite possibly be localised entirely within one's kitchen... $\endgroup$ Commented Apr 18 at 8:43
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    $\begingroup$ "Borealis" means northern. The other one is australis. $\endgroup$
    – AlexP
    Commented Apr 18 at 8:53

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The aurora are concentrated around the magnetic poles of the Earth alone, and this would be the case regardless of the relationship between those three reference frames. The Earth's rotation has very little effect on the aurora, and the direction of the sun with respect to Earth's field would also effect little, as the field concentrates the solar wind coming from all directions.

Now, there is a reason the three axis are correlated, the Earth spins because of angular momentum it was formed with, which would originally be aligned with the angular momentum of the entire planetary nebula the solar system formed from, and likewise the angular momentum of the molten metallic core of the Earth which generates the magnetic field. But if they were to be vastly misaligned, likely by the same processes that have them slightly misaligned today, the aurora would follow only the magnetic axis.

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    $\begingroup$ They are concentrated along a circular band some 10° to 20° away from the magnetic poles. And while the northern magnetic pole is indeed pretty close to the geographic pole (at 86° N, 162° E), the southern magnetic pole is far away from the geographic pole (at 64° S, 136° E). (Both magnetic poles are moving quite fast, so the coordinates may change significantly over the years. For example, the northern magnetic pole used to be at 76° N fifty years ago.) $\endgroup$
    – AlexP
    Commented Apr 18 at 8:58
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    $\begingroup$ Worse, there is archaeological evidence that Earth has its magnetic poles shift over its age, more than several times. So the actual physics of how the Earth's magnetic field is formed differs from the simple model you describe, and it pretty much can misalign with revolvement poles. If that would happen, or some more interesting things would happen like having several effective poles on the surface, the aurora borealis would be visible at night around all of them, because solar wind particles are travelling along the lines of the magnetic field. $\endgroup$
    – Vesper
    Commented Apr 18 at 9:04
  • $\begingroup$ @AlexP Not sure the point you are trying to make. Do you not consider a 10° band at 20° away from an axis to be "around" said axis? Likewise, I would still consider a difference in only 26° between two rotating axis to indeed be a "slight" misalignment, as far as planetary bodies are concerned. $\endgroup$ Commented Apr 22 at 19:07
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It would be way more visible, due to the magnetic poles aligning with the flow of the solarwinds. That being said- it would be way more intense on the anti-sunwards pole, way more focused there as the field has more time to bend the solwarwinds into the atmosphere to create plasma.

On the sundwards side- there would be a faintly glowing area in the center, and the aurora borealis would be deeper down south. The solwarwinds being bend down later by the field lines and slightly weakened.

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  • $\begingroup$ Thanks. Do we have any kind of mathematical model or rule of thumb which would tells us how visible it would be at a given latitude given the orientation of the poles to the sun? $\endgroup$
    – spraff
    Commented Apr 18 at 11:41
  • $\begingroup$ My assumption is based on visualizations: youtube.com/watch?v=k67OGI-ur3I and simulations: svs.gsfc.nasa.gov/4825 of solar wind.. Notice how its deforms the magnetic field. Now visualize the result of that deformation applied from pole to pole $\endgroup$
    – Pica
    Commented Apr 18 at 11:49

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