Aurora at Solar Maximum
Bingchen Hu
Award: Top 100
School: lynbrook high school
Teacher: jing xin
Category: Natural
Photo #20586
Aurora at Solar Maximum
The year 2025 was one of the golden years for aurora, because the Sun had reached the peak of its 11-year solar cycle. The increase in sunspots led to a higher frequency of massive plasma clouds formed by electrons and protons. When they reached Earth, they did not simply crash into the atmosphere. Instead, under the Lorentz Force, Earth's magnetic field guided and concentrated the particles within the Auroral Oval, a band typically centered near 67° magnetic latitude and spanning roughly 6° in width. They spiraled along invisible magnetic field lines toward the polar regions.
I had experienced the opposite before. In 2019, during solar minimum, I stood in Fairbanks, Alaska, waiting under dark skies, but the aurora never came. The Sun was quiet, and so was the sky.
But in December 2025, in Tromsø, Norway, everything was different. The auroral oval had expanded equatorward under intensified geomagnetic activity, and that night the sky suddenly ignited. Green curtains swept overhead, shimmering and folding like silk in motion. Through my camera's long exposure, something even more striking appeared, deep streaks of purple woven into the display.
The green light came from excited atomic oxygen about 100 kilometers above Earth, emitting its characteristic 557.7 nm glow. The purple hues were produced lower in the atmosphere by molecular nitrogen and ionized nitrogen, energized by higher-energy particle collisions. The strong presence of purple told a clear story: the particles were more energetic, a signature of solar maximum.
As the lights danced above the Arctic landscape, it felt like witnessing a conversation when solar plasma meets Earth's magnetosphere in a brilliant display of physics. So, I documented this interaction moment.
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