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The gyrocompass,
which is unaffected by the magnetism of the earth, consists of a gyroscope, with the
spinning wheel on an axis confined to the horizontal plane so that its axle aligns itself
with the north-south line parallel to the axis of the rotation of the earth, thereby
indicating true north.The Magnetic North Pole
Contrary to the popular belief, the
bobbing needle on a compass does not point to the North Pole at the top of our planet.
Instead , the magnetized needle of every compass points to a spot on the map just off the
northern coast of Bathurst Island at 76.5 degrees north latitude in the Canadian High
Arctic. This invisible spot, known as the magnetic North Pole, is actually 965 miles (1550
km) south of the geographic North Pole.
To make the situation even more
interesting, the position of the magnetic pole wanders just a little each year, a
phenomenon known as polar wandering. The direction of wandering has been observed to
reverse. During geologic history the polarity of the earth’s magnetic field has
periodically reversed. When it was first discovered in 1831 the magnetic north pole was
465 miles farther south than it is today.
For these reasons, using a
compass in the arctic requires very good navigational skills. Today, people are fortunate
in that a technology known as GPS (Global Positioning System) is an affordable and an easy
to use tool. By locating 3 or more satellites in orbit, it can pinpoint your location to
within 200 yards. One drawback to GPS units is that they run on batteries, which in the
extreme cold weather do not function very well. So it is wise that you know how to
navigate with a compass as a back up.
How to use a compass:
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