Earth’s Magnetic Shield Booms like a Drum

New research shows that the Earth’s magnetic shield booms loudly (when hit by impulses) but we cannot hear it because the frequencies are too low in pitch for human ears to pick up.

Earth has a magnetic field around it which collides with the solar wind, a stream of charged particles bombarded at Earth by the Sun, and forms a ‘Magnetosphere’. It acts as a shield from the powerful solar winds. The outermost layer of this magnetic shield is called the ‘Magnetopause’. When an impulse hits it, the force of the impact is absorbed and distributed evenly until it reaches the poles. From there, the force is reflected.

This process occurs in the same way as when someone hits the face of a drum. The magnetosphere has two sides. The one towards the Sun is huge. It extends about 10 times the radius of our planet. Movements in the magnetopause can impact how energy flows through the Earth’s space environment. Such interference can damage technological equipment such as entire power grids and GPS devices.

The Significance of Earth’s Magnetic Shield

We are extremely lucky that Earth has a magnetic shield otherwise we would have suffered the same fate as Mars. The red planet of our Solar System had an underdeveloped magnetic field which was not strong enough to protect it against the solar wind. The wind blasted towards the atmosphere and slowly tore it away. Fortunately, Earth’s magnetic field got the jump-start just in time when the core of the planet solidified. In order to capture the phenomenon in action, we would need several satellites in the correct positions at a precise time. The satellites would then pick up the vibrations within the magnetosphere. Martin Archer, a Space Plasma Physicist at Queen Mary University of London, elaborated the process by saying,

“This involved combining more realistic models of the entire dayside magnetosphere, as well as running global computer simulations of the magnetosphere’s response to sharp impulses. These models and simulations gave us testable predictions to search for in satellite observations. “Earth’s magnetic shield is continuously buffeted with turbulence, so we thought that clear evidence for the proposed booming vibrations might require a single sharp hit from an impulse. You would also need lots of satellites in just the right places during this event so that other known sounds or resonances could be ruled out. The event in the paper ticked all those quite strict boxes and at last, we’ve shown the boundary’s natural response.”

Discovery of the Magnetic Shield

Firstly, the scientists made a list of possible things needed to provide evidence for the drum-like phenomenon. It was decided that four satellites in a row would be required near the magnetopause. Luckily, NASA had five similar probes studying the polar lights. These were all that Archer and his team required. He acknowledged the role of these probes and referred to the symphony effects of the Earth’s magnetic field. He said,

“We found the first direct and unambiguous observational evidence that the magnetopause vibrates in a standing wave pattern, like a drum, when hit by a strong impulse. Given the 45 years since the initial theory, it had been suggested that they simply might not occur, but we’ve shown they are possible. Earth’s magnetic field is a gigantic musical instrument whose symphony affects us greatly through space weather. We’ve known analogs to wind and string instruments occur within it for decades, but now we can add some percussion into the mix, too. The frequencies we detected — [between] 1.8 and 3.3 millihertz — are over 10,000 times too low in pitch to be audible to the human ear.”

The following video from Archer will help you to better understand his findings.

In addition to that, there are too little particles in space to create a strong enough oscillation to move an eardrum. The THEMIS spacecraft of NASA had the required sensitive instruments to pick up the ‘drum sound’. The data had to be manipulated before it turned into something audible.

The Bottom Line

There’s so much we don’t know about the magnetopause and its capabilities yet. We also don’t know if other planets with strong magnetic fields like Jupiter and Saturn experience such phenomena or not. Understanding this research may help us study about the weather in space and may further aid in technological advancements that can keep our electronics safe from such interference.