The aurorae are created when some violent events on the Sun’s surface throw up a mass of charged particles into space.
A geomagnetic storm happens on the Earth when charged particles become trapped in the planet’s magnetic field and interact with atoms in the upper atmosphere.
These interactions finally produce aurorae.
These storms are rare, occurring around once in a few decades.
The last time charged particles from the Sun blew into the earth with similar energy and intensity was in 2003.
Both events happened as the Sun was nearing the peak of its solar cycle — an 11-year period during which the star’s magnetic field flips.
It creates magnetically active patches on the star’s surface called sunspots. These sunspots grow and shrink as solar cycles begin and end.
In the last solar cycle, no sunspot gave rise to a geomagnetic storm that matched the intensity.
For example, since early May 2024, scientists have been monitoring the sunspot AR 3664. It was growing in size; within a week it was 16 times as wide as the earth and brimming with magnetic energy.
The supercharged magnetic fields in such sunspots sometimes disconnect and reconnect in fractions of a second, releasing a great burst of energy that sends plumes of charged particles called coronal mass ejections (CMEs) into space.
CMEs happen together with solar flares (powerful flashes of radiation) and all these active events are collected under the term ‘solar storms’
Magnetic fields deflect charged particles, but the earth couldn’t prevent many of the particles from slipping through to locations close to the planet’s magnetic poles.
Here, their interactions with oxygen atoms in the upper atmosphere produced vivid red light and with oxygen and nitrogen in the lower atmosphere produced green and purple light, respectively. Thus, the world had its aurorae.
Dig Deeper: Read about the Role of Aditya L1 in anticipating a solar storm.
