The sky tinged with purple, a spectacle of the solar storm: the Northern Lights from Northern Europe to Italy, from the USA to Tasmania


By John

«Global Aurora», the first in decades. From Northern Europe to central Italy, from the United States to Tasmania, a spectacular Northern and Southern Lights have been admired at unusual latitudes across the planet, hit by a solar storm of an intensity unprecedented for at least twenty years. And it will continue to rage over the weekend, with potential dangers for satellites and even electricity grids, disturbing radio transmissions and even the orientation of birds.

Where the sky was clear, many enjoyed the show and millions of photos of skies with waving curtains in pink, purple or green flooded social media across the globe. In North America the phenomenon was also visible in southern US states, such as Alabama and California.

In Europe, among other countries also Slovakia, Switzerland, Spain and Poland and Italy, in particular in the Alpine areas, but also in the Apennines, up to Abbruzzo and Umbria, in addition to the usual Nordic countries , who are accustomed to the phenomenon even if it is typically winter. A solar storm is a violent emission of plasma, that is, highly charged particles from the Sun's photosphere in one direction, traveling at the speed of light.

Coming into contact with the Earth's magnetic field, the particles expelled from the Sun charge the upper layers of the atmosphere with energy. As a result, radio waves traveling in these areas lose energy due to more frequent collisions with electrons, which causes their degradation or even complete absorption.

The solar storm, classified as “extremely powerful”, or G4 level on a scale of 5 by NOAA, the US weather and space agency, was expelled by a group of sunspots whose overall diameter is 17 times that of the Terrestrial Earth, and is the result of an 11-year cycle of solar hyperactivity that has reached its peak.

The plasma expelled from the Sun traveled about 150 million kilometers at a speed much lower than that of light (observed from normal solar radiation), equal to about 800 kilometers per second, reaching the upper layers of our atmosphere around 6pm Italian time on Friday . Precautionary measures have been taken almost everywhere for the disturbances caused by the electromagnetic storm.

Starting from space, where Elon Musk's Starlink network alone has 5,000 satellites in low orbit. “The Starlink satellites are under heavy pressure, but so far they are holding up,” Musk himself wrote on his social media site X. And the astronauts on board the International Space Station have received instructions from NASA to take refuge in the innermost rooms, more sheltered from solar radiation.

The last powerful, abnormal solar plasma bombardment dates back to October 2003, the so-called Halloween Storm, which caused blackouts in Sweden and serious damage to the South African electricity grid, in the opposite hemisphere. Although the most powerful ever recorded by man was the so-called Carrington Event, named after the British astronomer Richard C. Carrington, an expert in solar observations, in September 1859.