Possible merger between two coronal mass ejections in the next few hours. Northern Lights also visible from Northern Italy
Two coronal mass ejectionscalled CMEs, will reach Earth in the next few hours. According to forecasts from NOAA’s space weather center, they could merge shortly before impact with the planet and create what is called a Cannibalistic CME. A scenario that could trigger a category G3 geomagnetic stormtherefore of a strong type. And if a complete merger of the two flows occurs, a storm cannot be ruled out reaches the G4 threshold “acute”, as has already happened on other occasions. According to experts, however, there is no cause for alarm. Indeed, with a bit of luck a spectacular event could occur between 11 and 12 November Northern Lights also visible from Italy.
What is a cannibalistic CME
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A CME is a stream of plasma and magnetic fields projected into space from the solar corona, the outermost layer of the Sun’s atmosphere. Each CME can contain billions of tons of electrically charged particleswhich travel at around 20 thousand km/s. When two ejections start within a short distance of each other, but at different speeds, the fastest one can reach and incorporate the slowest. From this overlap arises the so-called cannibalistic CME. According to NASA, ejections of this type produce complex and large magnetic clouds, capable of triggering geomagnetic storms that are longer lasting and more intense than ordinary ones.
What time will the cannibal CME arrive in Italy
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The two coronal mass ejections originated from X-class solar flares, recorded respectively on November 9 and 10 on the AR 4274 spot, which is particularly unstable. Unfortunately, it is currently impossible to precisely time the impact on Earth, but NOAA models indicate that the peak of magnetic activity should occur on the night between 11 and 12 November. In Italy, experts recommend keeping your nose up at 4am on Wednesday 12 November. The estimated Kp index is around 7 out of 9: this means that, at least in theory, it should cause Northern Lights even at medium latitudes. Net of local cloud cover, of course.
The effects of solar storms
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Geomagnetic storms are the result of the interaction between solar wind and the Earth’s magnetosphere. When charged particles coming from the Sun hit the planet’s magnetic field, they can induce electric currents and generate more or less intense disturbances. With G3 or G4 category events, that’s to be expected temporary anomalies in the functioning of satellitesinterference in long-distance radio communications And deviations of GPS signals. Only the most severe storms, such as Carrington in 1859, caused significant damage to the earth’s electrical grids.
What is the Northern Lights and how does it arise?
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The Northern Lights are an optical phenomenon caused by the interaction between solar wind particles and atoms present in the outermost portions of the Earth’s atmosphere. When these particles are excited by the flow of solar energy, they emit light and form features colored arches and curtainsarranged along the planet’s magnetic field lines. The colors of the Northern Lights depend on the altitude and the type of gas involved: the green comes from the oxygen located at around 100 kilometers above sea level, while the red comes from the more rarefied one above 200 kilometres; the blue and violet shades, however, are a product of nitrogen. During the most intense geomagnetic storms, as is the case these days, the light show can spread up to the middle latitudes and give a rare astronomical spectacle also visible from the regions of northern Italy.
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