The Northern Lights are once again illuminating the skies that are at latitudes as low as those of Italy: since the night between 11 and 12 November, a very intense geomagnetic storm has been underway which has reached the G4 class, the penultimate on the scale which reaches up to G5, and which is expected to continue in the next few hours. The spectacular phenomenon of the auroras already made their appearance last night in the skies of Northern Italy, particularly along the Alps, but next night could be even more favorable for enthusiasts, as Mirko Piersanti, professor at the University of L’Aquila and space weather expert, confirmed to ANSA: “Tonight the storm could be very intense, so it is absolutely probable that the auroras will be visible not only in the North”.
Auroras are due to the interaction between charged particles emitted by the Sun and the Earth’s magnetic field. Under normal conditions, particles slide along the outer edge of the magnetosphere until they reach the Poles, where our planet’s shield is weakest and allows particles to come into contact with the atmosphere. Here they excite the gas atoms, which emit light of different colors depending on the molecule. In the case of solar storms, however, the particles manage to penetrate the atmosphere much more than normal and the phenomenon of auroras thus becomes visible at unusual latitudes.
Such a strong geomagnetic storm, however, does not only bring with it positive consequences: G4 class events can cause problems for electricity networks and infrastructures, they can change the orientation of satellites orbiting the Earth making course corrections necessary, and they can cause interruptions in radio communications and satellite navigation systems such as GPS. Some of these events have already occurred, such as the radio blackout that affected Europe and Africa, interrupting high-frequency radio communications on the side of the Earth facing the Sun.
The storm was triggered by the arrival of two coronal mass ejections or Cme, i.e. ejections of matter in the form of plasma, one of which was accompanied by the strongest solar flare of 2025 so far, which reached class X5.1.
The origin of these phenomena is the sunspot indicated by the acronym AR4274, one of the most prolific producers of solar flares of the current solar cycle. “For several days we had already been keeping an eye on this active region – says Piersanti – which merged with other nearby ones reaching enormous dimensions. In recent days, among other things, it also produced other CMEs which however were slower and therefore did not reach the Earth”.
The storm is currently underway with an intensity oscillating between G3 and G4, according to data provided by the Space Weather Prediction Center of the US agency NOAA, but it could intensify further in the next few hours due to the expected arrival of a third CME. “At the moment the disturbance of the Earth’s magnetic field is associated with the arrival of only the first part of the Cme magnetic cloud”, underlines the expert from the University of L’Aquila: “If this has the right characteristics, we could witness an even stronger storm, perhaps the largest since the Carrington event of 1859”.
Aurora boreale at Plan de Corones. Photo: https://kronplatz.panomax.com/
Reproduction reserved © Copyright ANSA