The spring equinox will spark stunning auroras: Here's why
Skywatchers across the globe agree that the best time to catch auroras is around late March and late September, around the time of the equinoxes. The same applies to this year, where the March equinox will bring stunning auroras. While it is not completely understood, the most common explanation behind the connection between equinoxes and auroras is the orientation of Earth's magnetic field.
Why does this story matter?
For ages, this pattern has been observed that auroras peak around the time of the two equinoxes and, and decline around June and December, when the solstices occur. Data from the British Geological Survey reveals that, on average, a sizable magnetic storm happens on nearly twice as many days in March as in June or July.
The equinox falls on March 21 in India
The March equinox marks the beginning of spring in the northern hemisphere and autumn in the southern hemisphere. In the northern hemisphere, the March equinox will bring earlier sunrises, later sunsets, and sprouting plants while the opposite happens in the southern hemisphere: later sunrises, earlier sunsets, and falling leaves. In India, the equinox falls on March 21 (Tuesday) at 2:54 AM.
Equinoxes occur when the Sun is directly above the equator
Equinoxes occur twice a year when the Sun is directly above the equator. This is the only time when both the northern and southern hemispheres experience roughly equal amounts of sunshine.
Russell-McPherron effect explains why more auroras are seen around equinoxes
The Russell-McPherron effect describes why the Earth experiences heightened auroral activity around equinoxes. Just like magnets, the solar magnetic fields—which are carried to Earth by solar winds—have north and south poles. The theory shows that the north-south component of the solar magnetic field oscillates over the year, corresponding to Earth's axis. These fluctuations were found to be the largest during the equinoxes.
There is another factor called the equinoctial effect
Geomagnetic storms, which cause auroras, frequently occur when the north-south component of the solar wind is aligned more or less opposite the "north-south" component of Earth's magnetic field. This can be compared to how bar magnets of opposing polarity attract each other. There is also another factor at play, called the equinoctial effect, which increases the incidence of auroras around equinoxes.
Here's what happens during an equinox
During an equinox, the Earth's magnetic poles lie at right angles to the direction of the incoming solar winds, and this happens twice a day. When this occurs, the solar wind is effectively stronger and enhances magnetic storms. As the seasons change, Earth's poles either point more toward or away from the Sun, which thereby reduces this effect.
