3 ms·

Can anybody explain how moving any direction from the North Pole is anything but south? Or am I confusing magnetic north with rotational north?

jacobolus 11y ago
Unfortunately our language doesn’t have great words for concisely and precisely describing three-dimensional rotations, precession, etc. in plain words. (We can be precise by using diagrams or mathematical notation, or writing an extended paragraph of explanation.) Of course if we define the rotational axis to be the “north pole”, then it doesn’t make sense for it to be moving east, or even south: by definition whatever direction it points is always north. What they seem to mean is, if we predict the pole’s future path over the surface of the planet, previously it was moving toward Canada, and now it’s moving toward England. Relative to the N–S–E–W coordinate frame we use today, if we keep that coordinate frame static, the modified path of the pole is to the “east” of its original path.
- ahazred8ta 11y ago
  TL;DR - For a long while, the pole was slowly moving toward Canada. Then for about a decade, it slowly moved toward Europe. Now since about 2012, it is slowly moving toward Greenland. Based on gravity measurements, it looks like changes in global groundwater levels and icecaps are responsible for the changes in direction.
twelvechairs 11y ago
I believe are saying is that its moving (more) towards the eastern hemisphere (actually, only slightly east of London) than it was previously (when it was heading towards canada)
GFK_of_xmaspast 11y ago
There's a difference between the magnetic pole and the rotational pole.
vacri 11y ago
There's also geographic north, which is where the map lines (and hence 'eastward') come from. https://en.wikipedia.org/wiki/List_of_firsts_in_the_Geographic_North_Pole https://en.wikipedia.org/wiki/List_of_firsts_in_the_Geograph...
deleted 11y ago
[deleted]

jacobolus 11y ago

Unfortunately our language doesn’t have great words for concisely and precisely describing three-dimensional rotations, precession, etc. in plain words. (We can be precise by using diagrams or mathematical notation, or writing an extended paragraph of explanation.) Of course if we define the rotational axis to be the “north pole”, then it doesn’t make sense for it to be moving east, or even south: by definition whatever direction it points is always north. What they seem to mean is, if we predict the pole’s future path over the surface of the planet, previously it was moving toward Canada, and now it’s moving toward England. Relative to the N–S–E–W coordinate frame we use today, if we keep that coordinate frame static, the modified path of the pole is to the “east” of its original path.

ahazred8ta 11y ago
TL;DR - For a long while, the pole was slowly moving toward Canada. Then for about a decade, it slowly moved toward Europe. Now since about 2012, it is slowly moving toward Greenland. Based on gravity measurements, it looks like changes in global groundwater levels and icecaps are responsible for the changes in direction.

twelvechairs 11y ago

I believe are saying is that its moving (more) towards the eastern hemisphere (actually, only slightly east of London) than it was previously (when it was heading towards canada)

GFK_of_xmaspast 11y ago

There's a difference between the magnetic pole and the rotational pole.

vacri 11y ago

There's also geographic north, which is where the map lines (and hence 'eastward') come from. https://en.wikipedia.org/wiki/List_of_firsts_in_the_Geographic_North_Pole https://en.wikipedia.org/wiki/List_of_firsts_in_the_Geograph...

deleted 11y ago

[deleted]