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Magnetic field that helps radar detection weakening over North America, claims China

Updated: 08-11-2024, 10.41 PM

Scientists in China claimed that the magnetic shield over North America is weakening rapidly. The geomagnetic field, a kind of natural barrier, protects Earth from cosmic radiation, which can create disturbances in the atmospheric system.

The cause of the magnetic shield losing strength ‘exceptionally fast’ has yet to be determined. However, initially, it’s being linked to the shift of the geomagnetic poles from the western to the eastern hemisphere.

Scientists, led by Professor Fang Hanxian of the National University of Defence Technology, also revealed that the magnetic field over the eastern hemisphere, including China, is strengthening.

Significant reversal occurred in past 30 years

Chinese scientists published a peer-reviewed paper last month highlighting the weakening of magnetic shields.

Fang’s team employed the latest models and data to reconstruct global magnetic field strength changes since 1900. They found that from 1930 to 1990, the magnetic field strength in North America increased and was higher than in many other regions of the world, reported SCMP.

However, Chinese scientists claimed that a significant reversal has occurred in the past 30 years: by 2020, the magnetic field strength in this region had dropped to a level barely above the global average.

Scientists maintain that the change is exceptional from a global perspective.

Magnetosphere plays role of gatekeeper

An immense magnetic field, called the magnetosphere, surrounds Earth. Generated by powerful, dynamic forces, the magnetosphere shields us from the erosion of the atmosphere by the solar wind (charged particles our sun continually spews at us), erosion and particle radiation from coronal mass ejections (massive clouds of energetic and magnetized solar plasma and radiation), and cosmic rays from deep space.

NASA claims that the magnetosphere plays the role of gatekeeper, repelling unwanted energy harmful to life on Earth, trapping most of it a safe distance from Earth’s surface in twin doughnut-shaped zones called the Van Allen Belts.

Main magnetic field exhibits an increasing trend in Eastern Hemisphere

Earlier, it was claimed that the forces that generate Earth’s magnetic field are constantly changing; the field itself is also in continual flux, its strength waxing and waning over time.

According to NASA, this causes the location of Earth’s magnetic north and south poles to shift gradually and completely flip locations about every 300,000 years or so.

The study, published in the Chinese academic journal Review of Geophysics and Planetary Physics, claims that the main magnetic field exhibits an increasing trend in the Eastern Hemisphere.

At the same time, its variations in the Western Hemisphere are more diverse. In the last 120 years, the Earth’s dipole moment has decreased while the non-dipole moment has increased, which means the contribution from the dipole (non-dipole) field has decreased (increased).

In their recent study, Chinese scientists also claimed that the magnetic poles change more rapidly relative to the geomagnetic poles.

The direction and speed of movement differ in the Northern and Southern Hemispheres. In the Northern Hemisphere, the magnetic poles have crossed from the Western Hemisphere to the Eastern Hemisphere, while in the Southern Hemisphere, they have moved toward lower latitudes.

Over the past century, the magnetic pole in the northern hemisphere has been inching eastward at a speed of about 6.2 miles per year.

However, this process has recently accelerated significantly. The military can use the Earth’s magnetic field for ultra-long-distance communication and radar detection. Spacecraft and satellites rely on it as a protective umbrella to dodge devastation from solar storms. Some missiles can even navigate using the Earth’s magnetic field, according to SCMP.

Fang mentioned in the study that after 2000, the speed exceeded 31 miles per year, far surpassing the movement speed of the magnetic pole in the southern hemisphere.

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