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Where does a compass really point?
A compass in the Northern
Hemisphere truly 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 bane of boy
scouts, 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 seafarers
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.
- During
midsummer, the radical leaves of the compass plant invariably point precisely
north and south.
- The rings
of a tree are always farther apart on the tree's southern side. Woodsmen often
read tree rings to find the compass points.
- Honeybees
navigate using the Sun as a compass, even when it is hidden behind clouds -
they find it via the polarization of ultraviolet light from areas of blue
sky.
- Women
navigate by landmarks and visual memories. Men navigate by direction and
distance, and tend to be better at reading maps.
- According
to Aristotle, wind direction determined whether a baby would be a boy or a
girl.
- The Pole
of Inaccessibility is the point on the continent of Antarctica that is farthest
in all directions from the seas surrounding it. The term is sometimes used to
refer to the point in the Arctic Ocean that is equal distances from the
landmasses surrounding it.
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