buco coronale sole

A 1 million km large hole opened on the sun: what it is and what effects it will have on earth

A gigantic coronal hole Great beyond 1 million km It is right now dominating the southern portion of the sun. It is the coronal hole larger ever trained in recent years and, aiming for the earth, could cause geomagnetic storms medium -sized, with aurore even to lower latitudes than usual, Between Tuesday 20 May and Thursday 22 May. Coronal holes are regions of the outer layer of the sun atmosphere, the crown precisely, in which i Magnetic fields “open” leaving the transition to solar wind. I am therefore temporary conditions of the solar atmosphere in which a sun is expelled larger flow of particles energy Which, interacting with the magnetic field and the atoms of our atmosphere, can generate both spectacular auror, and disturbances to electric grids or satellites in orbit. Despite the increased flow of particles there is no need to worrysince the coronal holes are usually phenomena Less violent and less energy of the expulsions of Coronale mass, which instead can cause serious damage to the terrestrial infrastructures … but also great show such as the Aurora that dominated the Italian skies in May and in October 2024.

What is a coronal hole and how it forms on the sun

THE Coronal holes are regions of the external solar atmosphere (the crown) in which the magnetic field is “disturbed”. Instead of the classic closed lines of magnetic field that close on the sun surface, in a coronal hole The magnetic field lines “open”. Since the particles full of the solar atmosphere follow the magnetic field, the latter opening up that the solar wind can escape freely in spacegenerating jets of particles of intensity greater than normal that propagate in the sun system. If the coronal hole aims towards the earth, then the jet of particles that release from it can generate Geomagnetic storms.

Image
Schematic representation of a coronal hole. In regions A, the magnetic field lines are closed and retain the plasma of the crown. In region B (Coronal hole), the field lines extend into space and the plasma can escape along them. Credits: Sebman81, CC by -SA 3.0, Wikimedia Commons.

The cover image to the article was obtained by Solar Dynamics Observatorya NASA spatial telescope completely dedicated to sun monitoring. In particular, the image was obtained in the wavelengths of theExtreme ultravioletinvisible to the human eye. The lower the wavelength, the greater the energy transported by the light. The ultraviolet extreme allows us to observe the region of the solar crownwhere the temperatures are very high, of the order of million degrees. The coronal hole It appears darker because its density and temperature are lower than that of the surrounding regionsalthough the temperature continues to be frighteningly high. The hole currently present on the sun is one old knowledge. He was sighted for the first time in early February and cyclically reappeared at any rotation of the sun surface, surviving and expanding until now.

It follows for the earth: because there is no need to worry

The Spaceweather.com site, specialized in the setting of the solar activity, reports danger of G1 class geomagnetic storms (G5 are the most extreme) for the days Between 20 and 22 May. These possible storms will be generated by the interaction of the solar wind particles with the Earth’s magnetic field that re-index the particles towards the poles where they then interact with the atoms and molecules of the high atmosphere, generating spectacular phenomena such as the auror. The coronal hole currently visible on the sun has not trained now, but a Februaryperiodically returning to every rotation of our star.

Aurora Boreale Italy May 2024
Aurora Boreale seen from Chioggia (VE). Credits: Luigi Coppola.

Although this giant occupy the whole southern portion of the sun, its presence must not arouse particular concern. The flow of sun wind generated by the coronal holes is in fact lower intensity compared to that generated by more energetic events such as the Coronal mass expulsions. The forecast of G1 class storm will probably lead to weak fluctuations in the energy grids, a lesser impact in the operations of the satellites and aurore visible to lower latitudes than usual, but not so low that it can also be sighted in Italy.