Skywatchers in Europe, New Zealand, and parts of the northern United States were treated to a stunning display of green, purple, and red auroras on Sunday. These awe-inspiring light shows, also known as the northern and southern lights, were the result of a powerful solar storm, the fastest-moving in at least five years. However, the auroras quickly diminished as geomagnetic activity subsided.
One Finnish aurora enthusiast, Alexander Kuznetsov, described the evening’s spectacle as an amazing dance of vibrant red and purple auroras, making it a standout moment in his aurora hunting career. Another observer, Matti Helin, noted that although the display lasted only 20 minutes, it was still a remarkable sight.
The strong solar storm and subsequent brilliant light displays indicate that the sun is approaching its most active phase in two decades. Scientists anticipate more frequent and intense auroral activity in the coming years, including in the upcoming months.
The formation of auroras begins when the sun releases a surge of solar particles towards Earth, disturbing our magnetic field and causing a geomagnetic storm. These solar particles excite oxygen and nitrogen molecules in our upper atmosphere, resulting in the release of photons of light that manifest as the enchanting aurora.
The intensity of geomagnetic storms is categorized on a scale from 1 (minor) to 5 (extreme) by NOAA’s Space Weather Prediction Center. Sunday’s storm reached a G4 level but gradually weakened to G2 and G1 levels within a few hours.
Although the fast stream of solar particles continued to affect Earth’s magnetic field on Monday, its weakened connection to the coronal mass ejection limited the chances of strong auroral activity. Geomagnetic storming at G4 levels occurred during the daytime in the United States, making the light display difficult to observe. However, northern parts of the country still witnessed some dancing lights during the weaker nighttime storms.
New Zealand, on the other hand, had an advantage due to the pre-dawn timing of the solar storm. Despite some cloud cover, the aurora was still visible and surprisingly strong, even in the presence of a full moon.
The recent geomagnetic activity was traced back to a group of sunspots, darker and cooler areas on the sun’s surface with strong magnetic fields. These sunspots typically experience tangled and reorganizing magnetic field lines, eventually leading to energetic releases of energy.
Last week, there were intense eruptions and a solar flare event, resulting in electromagnetic radiation impacting Earth’s communication systems. Simultaneously, a coronal mass ejection, a burst of solar particles, emanated from the sun’s surface and reached Earth more rapidly than expected, at a speed of approximately 1.7 million miles per hour. This constituted the fastest-moving eruption observed during the current solar cycle.
The success of witnessing dazzling auroras, however, not only relies on a powerful coronal mass ejection but also requires the alignment of its magnetic orientation with Earth’s magnetic field. When these factors