Where does a compass really point?
A compass in the Northern Hemisphere truely does point in a northerly
direction, but not to the North Pole. Instead, the compass points to
the North Magnetic Pole, which, as Sir James Clark Ross discovered in
1831, is located at the northernmost point of the Artic coast of North
America. Similarly, a compass in the Southern hemisphere always points
to the South Magnetic Pole, which is firmly planted south of
Australia, in Antarctica.
The different directions their compasses pointed, when traversing the
high-seas of the Northern Hemisphere, baffled ancient mariners. Their
modern counterparts understand, and compensate for, the differences in
the North Pole and the Northern Magnetic Pole, and chart their courses
accordingly. The differences in the poles proves minor, in comparison
to the tricks the Northern Magnetic Pole pulls from its home of
Boothia. The bane of boyscouts, as they attempt to navigate with, or
without, the benefit of their trusty compasses, is the fact that this
Pole chooses to roam about in a 20-mile circle, and to shift its
course between day and night.
This 20-mile variance, however, is not one of global proportions.
Modern sea-farers compensate for the Northern Magnetic Pole's
perpetual motion, by using charts, and tools other than the compass.
All things considered, 20 miles is a minor measure for distant
travelers to take into account in adjusting their travel agenda.
Thankfully, the Southern Magnetic Pole spares sailors the navigational
nightmare its Northern nemesis does. In the south, compass needles
actually do point true South, to the South Magnetic field.
|
|