Last Tuesday the 14th, the Sun emitted the most intense flare in recent years, a type of phenomenon in which the star emits powerful, high-energy light radiation into space.

A few days before, a large part of the planet had been surprised by the unexpected spectacle of the auroras, in an episode that can now be classified as historic and was the result of the solar storm caused by the arrival of the various fronts on Earth. of particles that the Sun had ejected a few days before (these emissions are called coronal mass ejections).

Some flows that came from a set of sunspots with gigantic dimensions: 17 times the size of our planet and that could be seen through simple eclipse observation glasses.

A series of superlatives that indicate that the Sun is immersed in a period of intense activity. And although the appearance of auroras is the positive side of the matter, solar phenomena cause concern due to the effects they may have on our technology.

In recent days, specific disturbances have been recorded in the GPS positioning network and also in radio communications in some places on the planet. And it is expected that solar activity will continue to increase in frequency over the coming months, as the Sun approaches the maximum point that some sources place between the end of this year and the middle of next.

Over the past week, Sun observation satellites have detected a series of powerful flares, followed by at least eight coronal mass ejections, generated by the group of solar spots called 3664. In these emissions, enormous quantities of particles (mainly protons, electrons and helium nuclei) are launched into space, in a very directional way and with speeds that can reach 3,000 kilometers per second (in fact, the Sun is the most powerful particle accelerator in the solar system).

From the first moment, it was confirmed that the particle fronts would reach the Earth during the weekend and that they would generate geomagnetic storms. Indeed, although our planet’s magnetic field is responsible for capturing these emissions before they reach the surface, very intense flows can saturate the Earth’s magnetosphere and cause disturbances in communications, affect satellites and even induce electrical currents in power distribution plants and damage them (fortunately, the protection of the planet’s magnetic bubble is enough to avoid effects on life).

Based on the observations, the National Office of Oceanic and Atmospheric Administration of the United States (NOAA), one of the reference organizations for monitoring this type of events, generated a level G4 (severe) storm alert that , a few hours later, was increased to the maximum level G5 (extreme), a fact that had not happened for twenty years.

The arrival of the most intense wave of particles occurred during the night from Friday to Saturday (when the auroras could be seen from practically all of Europe), and during the weekend the NOAA geomagnetic storm alarms remained active, oscillating in ranges of severe and strong and even reaching, again, extreme at mid-morning on Sunday.

As a consequence, incidents were reported in the GPS positioning network as well as a degradation in the quality of radio communications in various areas of the Earth. However, despite the exceptional nature of the episode, so far no serious incident has been confirmed in satellites or power plants (some of these equipment were disconnected preventively).

The activity of the Sun (which translates into the observed number of sunspots, and events such as flares and mass ejections) oscillates in cycles of about eleven years (the existence of these solar periods was discovered in the middle of the 19th century). 19th century, by Heinrich Schwabe).

The serene behavior that the star shows at the beginning of a cycle changes, with the passage of time, until it reaches a high point in its activity and subsequently descends again to the minimum that will mark the beginning of the next cycle.

The current solar cycle is 25 and began in December 2009 (the origin of the numbering was located in 1755). Based on the study of the evolution of previous cycles, the present one was expected to be relatively mild, just like the previous one, and with its maximum located in July 2025. However, the solar activity observed in recent months is higher than expected , to the point that some sources point to the possibility that the peak could be advanced at the end of this year.

Therefore, it is to be expected that as we approach the maximum of solar activity, phenomena such as flares and mass ejections will increase in frequency (and, in some cases, perhaps also in intensity). Of course, these events have occurred throughout our history, but it is now that they acquire greater relevance in a much more sensitive world due to dependence on technology.

The most devastating solar storm recorded to date occurred in 1859. Known as the Carrington event (after the scientist who observed the solar flare that began the episode), it blocked telegraphic communications between Europe and the United States, even causing fires in some of the plants. It is believed that such an intense phenomenon would currently have catastrophic consequences and it would take months to fully recover from the effects.

In much more recent times, there are precedents for geomagnetic storms with severe impacts on infrastructure. Like the one that, in March 1989, left Canadian Quebec without electricity for hours. Or that of November 2003, which affected the energy supply in large regions of Sweden.

Solar cycles, and the phenomena associated with their activity, are powered by the powerful magnetic field of the Sun. It is the constant variations that this field experiences that generate sunspots, flares and mass ejections (the oscillations of solar magnetism They are so extreme that they cause the star to completely reverse the polarity between north and south in the eleven years that a cycle lasts)

However, the details of the specific functioning of the mechanisms that give rise to these phenomena are still the subject of research by science. The numerous studies carried out have led to a notable increase in our knowledge of the magnetosphere that surrounds the Sun, but nevertheless the details of the internal behavior of this magnetic field, its origin and its variations, remain not completely known.

Therefore, and because of the impact they can have on our society, the study of the Sun’s activity is one of the most dynamic fields of analysis in current astronomy. Likewise, constant monitoring of solar activity, carried out by specialized instruments that include satellites in space, is currently our best tool to anticipate the arrival of geomagnetic storms.