This week, unusually strong disturbances in the Earth's magnetic field have caused some stunning red auroras. This rare red glow is visible from locations across Europe and North America. Usually, the famous Northern Lights display mostly green hues. Although sometimes flashes or streaks of crimson hues are seen, the red sky is an unusual sight.
See also: Astronaut photographed impressive aurora around Earth
The spectacular display was caused by a massive plasma ejection, also known as a coronal mass ejection (CME), originating from the Sun.On September 24, a solar flare (CME) tore a hole in Earth's magnetic field, allowing charged particles to stream in and trigger a G2-class geomagnetic storm.
As these solar particles flow toward the poles, they interact with atoms and gas molecules in atmosphere , causing excitation and interaction. They then release photons, creating the dazzling display of lights known as the aurora borealis (or Northern Lights) and aurora australis (Southern Lights).
This phenomenon is completely normal, as charged solar particles create small holes in our magnetosphere. These holes are usually very small and do not pose a threat to us, the inhabitants of the earth.
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What makes this latest geomagnetic storm a little different is that the solar particles managed to collide with oxygen molecules high in Earth's atmosphere. Typically, solar winds reach altitudes between 100 and 300 kilometers, where there is a high concentration of oxygen to react with. When this happens, the light turns green, which is why that color dominates the horizon.
However, in this case, the charged particles are at an altitude of between 300 and 400 kilometers, where the oxygen concentration is sparse and requires a greater amount of energy to excite. The result is a dazzling flash of red light, although these ruby auroras are delicate and can only be observed if the oxygen atoms remain stationary long enough to release their red photons.
The human eye is less sensitive to red light than green, which is why red auroras are rare. This imbalance is another reason why this happens. However, we didn't experience any such problems this week. According to Spaceweather, the red lights were visible to the naked eye as far away as France.
See also: NASA's GREECE rocket studies the Northern Lights
As the Sun intensifies its activity and approaches Solar Maximum in July 2025 (or even earlier), we expect to enjoy even more spectacular performances in the sky.
