Last night, Italy had a special show: the boreal aurora shined in the North of Italy.
Our unusually active Sun produced a surface explosion a few days ago that sent out a burst of electrons, protons, and more massive charged nuclei. This coronal mass ejection triggered auroras on Earth that are being reported unusually far south in Earth’s northern hemisphere.
The image is from the Italian Alps. The unusual aurora has been visible in few regions of the North of Italy with naked eyes.
Typically the auroras are green, but it is impossible to observe green auroras at Italian latitudes.
When charged particles emitted by the Sun interact with oxygen molecules present in our atmosphere at 100-300 km above sea level, auroras appear. If the geomagnetic storm is intense enough, however, it can also interact with individual oxygen atoms present higher up (400 km). This interaction produces red auroras, and being higher up it is also visible from a greater distance, even from thousands of kilometers.
Photography credits:
https://www.giorgiahoferphotography.com/
References:
