Re: [Phys-l] Is something wrong here?????

[Hugh Haskell <haskellh@verizon.net>]

At 2:26 PM -0700 2/14/12, John Denker wrote:
> Suppose you are initially near the south pole and flying directly toward
> it.  Your true heading will be 180.  As you pass over the pole, your
> true heading will snap to 360.  There is no ambiguity about this whatsoever.
> Longitude has got nothing to do with it.
>
> If you are at the south pole and wish to fly toward a particular point,
> you cannot specify it in terms of heading.  You can specify it in terms
> of longitude, but that is not the same thing.
>
> There is a singularity in the coordinate system at the pole.  Wishful
> thinking will not make the singularity go away.
In the polar regions air navigation is not by the 
Lat/Long convention, but by a square grid 
oriented parallel to the 0/180 meridian, and 
tangent to the earth near the mid point of the 
intended flight path.Compases are set to O° 
parallel to the Greenwich meridian (180° when 
heading north along the 180° meridian). This 
enables navigation to "look" reasonably normal, 
and gives a fixed heading to a track between 
points near, but not crossing, the pole.

With regard to the direction from the pole, of 
course, any location is *only* north of the south 
pole, but by convention, east Antarctica is that 
part of the continent that lies in the "Eastern" 
longitudinal hemisphere (the part of the 
continent in which the Vostok station is located) 
, while west Antarctica lies in the "Western" 
hemisphere (where most of the US Antarctic 
stations are located--McMurdo Station, the chief 
US Antarctic base is located very close to the 
180th meridian). Nevertheless, talking about a 
location "southeast of the pole" is pure 
nonsense. The only description of a non-polar 
location that makes sense is by Lat/Long.

And of course, the entire continent is too close 
to the south magnetic pole for magnetic compasses 
to be of any use at all.

Caveat: I was last in Antarctica, and using the 
grid system of navigation described above, long 
before the modern air navigation systems (GPS, 
et. al.) were developed, so the system now in use 
could be different from the grid system I knew.

Hugh

--
Hugh Haskell
mailto:hugh@ieer.org
mailto:haskellh@verizon.net

I have been wondering for a long time why some of 
our own defense officials do not
put more emphasis on finding a good substitute 
for oil and worry less about where
more oil is to come from.  Our people are 
ingenious. New discoveries are all around
us, and when we have to make them, we nearly always do.

						Eleanor Roosevelt
						February 13, 1948