An interesting map showing the locations of North Magnetic Pole since 1590. The North Magnetic Pole moves over time due to magnetic changes in the Earth’s core. Today, the Geographic North Pole (the point in the Northern Hemisphere where the Earth’s axis of rotation meets its surface, the northernmost point on the Earth) differs from the North Magnetic Pole by about 500 kilometers (311 miles).
If a magnetic compass needle is allowed to rotate about a horizontal axis, it would point straight down at the North magnetic
The magnetic North Pole moves in loops of up to 50 miles (80 km) per day. But its actual location, an average of all these loops, is also moving at around 25 miles a year.
In the last 150 years only, the magnetic pole has wandered a total of about 685 miles (1,102 kilometers).
The South Magnetic Pole also moves in a similar fashion. But, since the Earth’s magnetic field is not exactly symmetrical, unlike the geographic north and south poles, the North and South Magnetic Poles are not antipodal, meaning that a straight line drawn from one to the other does not pass through the geometric center of the Earth.
The direction in which a compass needle points is known as magnetic north. In general, this is not exactly the direction of the North Magnetic Pole (or of any other consistent location). Instead, the compass aligns itself to the local geomagnetic field, which varies in a complex manner over the Earth’s surface, as well as over time
Historically, the magnetic compass was an important tool for navigation. So, how can you find the true north (geographic north) with a compass? The local angular difference between magnetic north and true north is called the magnetic declination.
Detailed maps typically tell you how much local deviation there is between magnetic north and true north (magnetic declination). You then offset your compass by that many degrees, and you’re all good. These type of maps (for example, military maps) are get updated in every few years or so.
To add to that, some maps in northern regions, such as Alaska, have numerous adjustments for deviations depending on what part of the map you are in.
Also in the Canadian Arctic pilots simply don’t use magnetic compasses because they’re too unreliable in the region.
Why does the North Magnetic Pole move?
Earth’s inner core consists essentially of nickel and iron and has a radius of 1,220 km (760 mi). The density in the core is indicative of the fact that there must be heavy substances like gold, palladium, platinum, tungsten, and silver.
The temperature of the inner core is anticipated to be about 5,700 K (5,400 °C; 9,800 °F). Now, the reason why iron and other metals can remain solid at such high temperatures is that their melting temperatures drastically elevate at the pressure present at the core, which can roughly hover around 330 to 360 gigapascals.
The outer core, which has been found to be liquid (as per the seismic research), is 2300 km thick, and the radius extends around 3,400 km. The density is anticipated to be much higher than the crust or mantle, which varies between 9,900 and 12,200 kg/m3. The outer core is considered to be developed with 80% iron, along with nickel and some other lighter elements.
Due to its high temperature, the outer core remains in a low viscosity fluid-state that ensures turbulent convection and rotates quicker than the rest of the planet, creates a dynamo effect. This is what creates the Earth’s magnetic field.
The average strength of the magnetic field in Earth’s outer core is said to be 50 times the strength of the magnetic field recorded on the Earth’s surface.
The changes in the Earth’s magnetic field is the reason for the position shifts of the north and south magnetic poles. But it isn’t widely understood how and why this dynamo effect changes over time.
The main reason is most likely shifts in the rate of spin of the Earth’s outer core and the currents within the molten material.
Irregularities where the core and mantle meet can be another reason.
Large earthquakes can change to the Earth’s crust and affect the rotation of Earth very slightly, so they can also cause small changes in the Earth’s magnetic field.
The poles can also switch places. Over the life of the Earth, the orientation of Earth’s magnetic field has reversed many times, with magnetic north becoming magnetic south and vice versa – an event
Evidence of geomagnetic reversals can be seen at mid-ocean ridges where tectonic plates move apart and the seabed is filled in with magma. As the magma seeps out of the mantle, cools, and solidifies into igneous rock, it is imprinted with a record of the direction of the magnetic field at the time that the magma cooled.