the chances of seeing a polar aurora in Italy this evening

In the afternoon of Today, Friday, June 28, 2024the Terra was hit by a very violent geomagnetic storm. Secondo lo Space Weather Prediction Center della National Oceanic and Atmospheric Administration (NOAA) the phenomenon has reached such an intensity that it falls into Class G4, the penultimate in order of power on a scale of five (from G1 a G5). The US federal body had predicted a weak Class G1 solar storm for today, due to acoronal mass ejection (CME) associated with a gigantic filament emerged on the southern surface of stella June 25. The flow of electrically charged particles (plasma) expelled towards our planet it hit the Earth’s magnetic field with a speed and strength significantly greater than expected, giving rise to a much more powerful geomagnetic storm, i.e. a G4 (acute) from around 4.18pm Italian time.

In these conditions there were many of the “ingredients” for the appearance of thepolar aurora in the skies ofItaliaas happened on the night between 10 and 11 May 2024, however the intensity of the solar wind – and with it that of the geomagnetic storm – has diminished over the course of an hour. In fact, until shortly after 5:00 p.m. the portal specializing in space weather spaceweatherlive.com indicated an index Kp8 (red), at 5.22pm we went down to Chapter 5 (yellow) with geomagnetic storm downgraded to G1.

The Kp index is an indicator which, in very simple words, measures geomagnetic activity; the higher the value, the greater the chance that auroras may occur at latitudes lower than those usual in the Northern Hemisphere (Northern Lights). The ladder will give 1 to 9 and, as indicated, in the early afternoon of today we jumped almost to the maximum level. As far as Italy is concerned, polar auroras become probable starting from a Kp index of 7 – 8 (but it is only one of the many factors involved). Unfortunately, as indicated, at the time of writing this has fallen to Chapter 5. A new “flare-up” cannot be completely ruled out in the next few hours, but we are not facing Repeated CMEs as in the case of May; there was only one coronal mass ejection on June 25 from a colossal “fire tongue“in the southern hemisphere of the Sun, a “cold” filament of solar material bound to areas with magnetic fields of opposite polarity.

The bad luck for Italy, from the point of view ofauroral activitywas also the time when the geomagnetic storm and the Kp index reached their maximum intensity. The colored arcs of the polar auroras become visible in the dark, as tourists who travel to Norway and Finland to witness the phenomenon (much more likely at high latitudes due to the Earth’s magnetic poles) know well. Today we would have had to wait at least until after 9:00 p.m. to have a chance to see the wonderful optical phenomenon. It would certainly have been easier to observe from Northern Italy and especially from mountain ranges such as the Alps, but the event of May 10-11 reminds us that the aurora can also appear in the skies of southern Italy, if the geomagnetic storm is sufficiently strong.

At this time spaceweatherlive indicates “moderate” disturbance conditions of the Earth’s magnetic field in relation to solar storms. The density of the solar wind it is also moderate (23.11 p/cm3), while its speed is around 450 kilometers per second. As specified, a new surge cannot be completely ruled out in the next few hours, but the chances of seeing polar auroras in Italy today, with current conditions, are practically non-existent.

Let us remember that the polar auroras are only the most suggestive and fascinating element of a phenomenon that poses serious risks to our safety. An extreme geomagnetic storm (classe G5) can destroy power lines, satellites, the internet, radio communications and GPS navigation, plunging us back into a true technological Middle Ages even for months. The risks are enormous and according to experts the infrastructures are not ready for an event of this kind, similar to that of Carrington that hit the Earth in 1859.