15 Nov
2006
15 Nov
'06
10:24 a.m.
Jules Richardson wrote:
Sridhar Ayengar wrote:
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
Jules Richardson wrote:
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? 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.