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What is Earth's magnetic field? -

Earth is a giant, spherical magnet. It's surrounded by a magnetic field that shifts over time and space. This field comes from various sources within and outside Earth.

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Like a bar magnet -

It's very similar to the field created by a bar magnet, only placed at Earth's center. Magnetic fields are created by moving electric charges. In a bar magnet, these charges are electrons orbiting in atoms.

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Core elements - Inside Earth, these moving charges are electrons carried by circulating currents of molten iron.

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Pioneer -

Scientists have studied Earth's magnetism for centuries. William Gilbert, a 17th-century English physicist, pioneered this field. His experiments and use of terms like "electric force" and "magnetic pole" laid the groundwork for modern electricity.

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Giant magnet -

Gilbert’s 1600 book, 'De Magnete', revolutionized the understanding of magnetism. After extensive research, he proposed that Earth behaves like a giant bar magnet, explaining compass needle behavior and magnetic variations linked to geographical features.

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Findings -

He discussed Earth's magnetism using a model: a spherical piece of loadstone called a terrella (little Earth). Magnetic needles placed on a terrella point towards the north pole (marked as point A). Even on an uneven surface, like at point O, needles still point north.

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Vintage equipment -

In the early 1800s, scientists studied Earth's magnetism using dip needles. These measured the angle of Earth's magnetic field at any point. Needles align horizontally at the equator and vertically at the poles. Scientists used dip needles on expeditions from the 18th century.

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Discovery -

Scottish Rear Admiral Sir James Clark Ross first discovered the North Magnetic Pole in northern Canada in 1831, after a couple of Arctic expeditions.

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Tech advancements -

A deeper understanding of Earth's magnetic poles led to navigational advancements. The "True Course Finder," for example, automated calculations for sailors, eliminating the need for complex formulas. Before these devices, sailors could only determine magnetic north with a compass, requiring additional calculations for true north.

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On the move -

For centuries, scientists have tracked the magnetic North Pole. Unlike the stationary geographic North Pole, the magnetic North Pole is constantly moving. Between 1600 and 1900, it moved about six to nine miles (10-15 kilometers) per year.

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Siberia-bound -

In the 1990s, it drifted into the Atlantic Ocean before accelerating towards Siberia. By the early 2000s, the speed had increased to about 34 miles (54 kilometers) per year.

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Siberia-bound -

In 2005, Canadian geophysicist Larry Newitt and French geologist Jean-Jacques Orgeval aimed to pinpoint Earth's magnetic field in an expedition to the Canadian Arctic. They confirmed that the wandering pole had crossed into international waters and was heading toward Siberia.

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World Magnetic Model -

The World Magnetic Model (WMM), developed jointly by the US National Geophysical Data Center and the British Geological Survey (BGS), is a large-scale model of Earth's magnetic field used to predict the pole's location. The WMM is updated every five years, with the latest version now available.

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Hitting the breaks -

While continuing its journey towards Russia, the magnetic North Pole migration has slowed to about 22 miles (35 kilometers) per year over the past five years. This rate of deceleration is unprecedented, according to scientists. 

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Canada vs. Russia -

A team led by Professor Phil Livermore of the University of Leeds has proposed an explanation for the recent behavior of the magnetic North Pole. He suggests that the pole is caught in a tug-of-war between two competing magnetic forces, one beneath Canada and the other beneath Siberia.

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Canada vs. Russia -

Livermore suggests that the Canadian magnetic patch has elongated and split, potentially strengthening the Siberian patch. This shift in balance could explain the pole's drift towards Russia.

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What causes the movement? -

Earth's outer core is primarily molten iron, a liquid metal. As heat escapes from the core, this molten iron moves, generating Earth's magnetic field.

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Swirling around -

Unpredictable changes in the swirling motion of this molten iron, located about 2,000 miles (3,218 kilometers) beneath the surface, influence Earth's magnetic field and the position of the magnetic pole.

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Hot tea -

"It's like a giant cup of tea," explained William Brown, a global geomagnetic field modeler at the British Geological Survey. "It's a hot liquid with the viscosity of water."

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Real-world implications -

The movement of the North Magnetic Pole is crucial for accurate navigation. The data collected from tracking its movement is used to calibrate compasses and other navigation devices.

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GPS and smartphones -

It plays a role in everyday GPS systems, including the compass function on our smartphones.

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Military navigation - The military also relies on the World Magnetic Model for precise submarine navigation, especially in challenging environments like the Arctic.

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Airports -

Airport runways are numbered based on their compass direction. As Earth's magnetic field shifts, these numbers must be updated. For example, Berlin Brandenburg Airport's north runway changed from 25R/07L to 24R/06L in October 2024.

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Constant monitoring -

While predicting exact movements is impossible, the BGS continues to monitor Earth's magnetic field. They use a network of ground stations and satellites to map the field in various locations.

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Pole flip? -

Given that scientists know the molten iron in Earth's core is constantly swirling and the magnetic poles are always moving, is it possible for a complete reversal to occur, where North becomes South and vice versa?

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Magnetic field flip -

While geomagnetic pole reversals aren't common, they have occurred throughout Earth's history.

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Magnetic field flip -

The last full reversal occurred 780,000 years ago. A temporary reversal happened 41,000 years ago, but it only lasted 250 years before returning to the positions the poles remain in today.

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No reason to worry -

While geomagnetic pole reversals may sound alarming, they occur over a long period and pose no immediate threat to life. Scientists have confirmed that such events do not cause significant short-term changes to Earth's environment.

Sources: (The Times) (USA Today) (Britannica) (National Centers for Environmental Information)

See also: How many of these amazing Earth facts did you know?

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