What is the direction the compass would point at when it was used at the South Pole (the magnetic pole)? Answer:
- There is no fixed pointing direction if the compass was holding flat. Every directions, in the line of great circle, will go through the North.
- It will point at the ground and sky when it was holding upright.
In the words of Physics, the behaviour can be explained by the fact that magnetic fields coming out from the poles are vertical. The compass needle does not interact with the fields which is perpendicular in direction. But if we hold up the compass vertical. Then the needle, in the plan of the fields, will turn to align with the lines of fields.
The South Magnetic Pole is not static. It constantly shifting due to changes in the Earth's magnetic field. As of 2005 it was calculated to lie at 64.53 S, 137.86 E, just off the coast of Wilkes Land, Antarctica. That point lies outside the Antarctic Circle. It is moving north west by about 10 to 15 kilometers per year.
PS: Study shows that the poles have flip-flopped many times over the past four billion years. On average, polarities of the poles swap every few 100,000 years. There have been a number of suggestions that the poles are going to swap within the next 1,000 years.
Ref:
- http://www.newton.dep.anl.gov/askasci/gen99/gen99271.htm
- http://simple.wikipedia.org/wiki/South_Pole
- http://en.wikipedia.org/wiki/North_Magnetic_Pole#Polarity
