Although it may sound quite unbelievable, auroras—or what we now call ‘northern lights’—blazed near the equator 41,000 years ago due to magnetic fields’ change.
On Thursday, Dec. 16, experts at the American Geophysical Union’s (AGU) annual online conference in New Orleans said that this geomagnetic disruption, known as the Laschamp event, is due to the planet’s north and south magnetic fields diminishing.
During the AGU meeting, presenter Anit Mukhopadhyay, a doctoral candidate in the Department of Space and Climate Sciences at the University of Michigan, noted that the magnetosphere’s strength decreased “to nearly 4% of modern values” and leaned in its favor around 41,000 years ago.
The scientists added that the magnetic field has shifted along its axis and is now only a fraction of its former intensity.
This phenomenon reduces the magnetic pull that typically drives the sun’s high-energy particles to the north and south poles. They interact with molecules in the atmosphere to brighten the night sky as the northern and southern lights.
“The geomagnetic tilt was significantly skewed from the geographic poles,” said Mukhopadhyay. “This led auroral precipitation to follow the magnetic poles and relocate from the geographic polar regions of Earth to equator-ward latitudes.”
As Mukhopadhyay’s research reported, the magnetosphere decreased by around 3.8 Earth radii during the Laschamp event, although it never dissipated entirely.
The poles once positioned north and south shift toward equatorial latitudes during this period of diminished magnetic field strength, and the aurora follows.
Mukhopadhyay added that this substantial geomagnetic shift might also impact changes in the Earth’s atmosphere and affect living conditions across the globe.
The magnetic field of the Earth is formed by the agitation of the planet’s molten core.
Magnetic field lines link the poles in a circular arc. According to NASA, they constitute the magnetosphere, a zone that protects the Earth from radioactive particles from space.
The magnetosphere also shields the Earth’s atmosphere from abrasion caused by the solar wind, a stream of particles pushed outward by the sun.
The scientists’ data do not establish a cause-and-effect relationship between Laschamp’s magnetic field changes and significant ecological consequences on the planet.
However, the research provided suggestions for future studies to confirm such a link, as Mukhopadhyay stated according to LiveScience.