Why does the north pole of a magnet rests along the north pole of the earth?

While a compass is a great tool for navigation, it doesn't always point exactly north. This is because the Earth's magnetic North Pole is not the same as "true north," or the Earth's geographic north pole . The magnetic North Pole lies about 1,000 miles south of true north, in Canada.

And making things even more difficult for the compass-wielding navigator, the magnetic North Pole isn't even a stationary point. As the Earth's magnetic field changes, the magnetic North Pole moves. Over the last century, it has shifted more than 620 miles (1,000 kilometers) toward Siberia, according to scientists at Oregon State University.

This difference between true north and the north heading on a compass is an angle called declination. Declination varies from place to place because the Earth's magnetic field is not uniform it dips and undulates.

These local disturbances in the field can cause a compass needle to point away from both the geographic North Pole and the magnetic North Pole. According to the United States Geological Survey, at very high latitude , a compass needle can even point south.

By using charts of declination or local calibrations, compass users can compensate for these differences and point themselves in the right direction.