Polar Reversals: South-Pole Pointing Compass
Imagine your compass pointing south instead of north.
If you were alive to see it 800,000 years ago, it would have been the Magnetic South Pole.
It takes 200,000 to 300,000 years for Earth’s magnetic field to flip polarity. Flipping polarity means the lines of attraction that enter the Earth would flip north to south pole, or vice versa.
This means that it has been twice that long since the last reversal. Some believe we are long overdue for a pole reversal. South-Pole Pointing Compass
But there’s really no need to panic:
NASA scientists say a reversal happens over hundreds or thousands of years. It’s not exactly a clean back flip that happens like a flick of a switch.
Why Does the Earth Have a Magnetic Field in the First Place?
Geophysicists believe Earth’s magnetic fields presence is because of what the Earth is made up of. South-Pole Pointing Compass
The Earth consists of a solid iron core. Surrounding the iron core is an ocean of hot, liquid metal. The liquid metal that flows in Earth’s core creates electrical currents, which in turn creates our magnetic field.
Unlike a solid fridge magnet, the liquid metal surrounding the inner core moves freely. This explains why the magnetic pole can migrate.
Although geophysicists cannot measure the inner core directly, this is why there is a strong belief that the matter governing Earth’s magnetic field moves around. South-Pole Pointing Compass
Magnets, Compasses and North Bearings
The Geographic North Pole differs from the Magnetic North Pole by about 500 kilometers.
The Geographic North Pole is where lines of longitudes converge into what we call the North Pole. The Magnetic Pole is a point in Northern Canada where the northern lines of attraction enter the Earth.
A compass needle will point to the direction of the Magnetic North Pole. But this doesn’t mean that a compass always points to the Geographic North Pole. This difference is magnetic inclination.
The Earth’s magnetic north is changing every day because of the hot, liquid metal that surrounds the inner core. It can change so much that the Earth’s magnetic field can flip polarity. This is called the Polar Reversal Theory.
Next time you’re out in the woods with your compass, don’t forget about the small magnetic pin that moves freely in the direction of the Magnetic North Pole.