VCF 9 (Jay West) & (Jules Richardson)

[Sridhar Ayengar]

Jules Richardson wrote:
> Sridhar Ayengar wrote:
>> Jules Richardson wrote:
>>> Well, given that VCFs are not unique to the US, I'm tempted to 
>>> suggest that they should always be given as coordinates anyway :-)  
>>> (Although what the longitude of the south pole is, I don't know - do 
>>> people just pick something at random? :)
>>
>> The Earth's axis precesses fairly quickly.  I don't think the South 
>> Pole is a single point on the surface from one moment to the next.
> 
> Interesting - I know the magnetic pole shifts around (and of course the 
> ice on the surface presumably moves around quite a bit, taking any 
> buildings with it), but surely 90deg south always points to the 
> geographical pole, no matter what the magnetic pole might be doing?

90 degrees south always points to the South Pole.  It doesn't always 
point to the same place, though.  The precession of the Earth's 
rotational axis causes the location of all coordinates on the Earth's 
surface to shift by a small amount all the time.  It's most easily 
noticed at the poles.  Barring smaller corrections of much shorter 
period and magnitude, the Earth's axial precession occurs on a period of 
about 26,000 years.

Peace...  Sridhar