Where does a compass point if you're at the North Pole?

You may think of the North Pole only as the top of the world—its northernmost point. But it turns out there are lots of north (and south) poles on our planet.

There is a town in Alaska called North Pole, which isn't near any of the other north poles (but it does get snow and receives a lot of mail addressed to Santa Claus). There is the geographic north pole, known as "true north." This is the spot in the Arctic Ocean where all lines of longitude converge on a map. There is also the instantaneous north pole, where Earth's rotational axis meets its surface. The instantaneous north pole is not in one fixed place. It moves in an irregular circle caused by the “Chandler wobble”, named for astronomer Seth Carlo Chandler who discovered in 1891 that our planet wobbles as it rotates.

The magnetic pole describes the two locations (north and south) where the planet's magnetic field is vertical. So if you're standing over the north magnetic pole with a compass, the needle would dip and try to point straight down—hence its other name: the magnetic dip pole. Over the south magnetic pole, your compass needle would point upward.

The north magnetic pole in recent years has started shifting quickly toward Siberia. Its annual movement has accelerated from 10 to 50 kilometers, says Larry Newitt, an emeritus scientist with the Geological Survey of Canada, who has flagged the pole's location on many expeditions since 1973.

From a physics standpoint, the north needle of a compass (or any magnet) points to what is physically—but not in name—the south magnetic pole of the earth, in other words, in the direction of the Arctic.