Last night of Friday, May 10, was very special in different parts of Spain: the night sky was dyed with colors by the northern lights, a phenomenon that is normally only perceptible in very northern latitudes and that, however, is could see in the Peninsula, in places as far away as Catalonia, Madrid, the Valencian Community, Andalusia or the Canary Islands.

Being a more common phenomenon in Nordic countries, many Spaniards have asked themselves the same question: Why are there so many northern lights? To this question, science once again has the answer: the key lies in solar activity.

The northern lights or also called northern lights are a phenomenon that depends on whether it is easier to see in the areas closest to the poles, if the necessary conditions of darkness, cold and clear skies are met. If they are very intense, they can be observable in non-boreal latitudes, but it is still very rare for them to be seen in countries like Spain.

As we mentioned before, the reason is found in solar activity, since the northern lights are formed when certain charged particles that come from solar flares collide with the gases that make up the Earth’s atmosphere, creating an impact that excites the atoms of the gases. . Energy is thus released in the form of light. The color that colors the skies depends on the type of gas and the height at which it is found.

These particles travel through space and collide with the Earth’s magnetic field, which is stronger in the center and weaker at the poles, which is why the particles enter the polar areas. However, if solar activity is high, the density of particles will be able to pass through denser areas of the magnetic field. This is the reason why the northern lights have been seen exceptionally in Spain and other parts of Europe.

The solar activity on which the auroras depend is cyclical and registers a peak approximately every 11 years. And right now the Earth is at one of those peaks. As reported by the State Meteorological Agency (Aemet) from its official X account (formerly Twitter): “Polar auroras are being observed at very low latitudes in the northern hemisphere, including Spain. There are many photographs that attest to this.”

The colors of the auroras depend on several factors. Oxygen is related to red and green photons, while blue and violet come from the excitation of nitrogen atoms; It is for this reason that green predominates in the lower layers of the atmosphere, while in those above 240 kilometers in height it is mixed with red.