An overactive sunspot has been acting up for the past week, to the point of causing a radio blackout on Earth.
It’s not just humans who celebrated 2023 with spectacular fireworks. Since the beginning of the year, the Sun has also had a field day. It currently hosts an exceptionally active sunspot; on January 9, it generated a violent X-class solar flare that caused a brief but intense radio blackout in the Pacific.
These sunspots are dark areas on the surface of the Sun. They appear as a result of local variations in the magnetic field. They regularly give birth to phenomena called solar eruptions, by analogy with the volcanoes that we know on Earth.
An X-class solar flare
The difference is that there is no lava outpouring; instead, a torrent of electromagnetic waves results. And when this deluge of particles is particularly intense, it can tear a bubble of plasma from the crown of the star. We then speak of coronal mass ejections, and these are likely to travel towards the Earth. If necessary, this can cause significant damage to electrical installations on land.
These eruptions are classified using a nomenclature that begins with a letter: A, B, C, M or X. It is the latter that includes the most intense phenomena.
This letter is followed by a number; it illustrates the size of the eruption in this category. Note that this is a logarithmic scale, like the Richter scale which classifies earthquakes. A small increase in the number therefore corresponds to a large increase in the intensity of the eruption. In this specific case, it was a Class X 1.9 flare.
It was therefore an eruption intense enough to have consequences on Earth. According to Spaceweather.com, a site specializing in tracking these events, the eruption disrupted radio communications in the Pacific as well as in Central and South America. The disruption was fortunately short-lived.
The last gasp of an overactive sunspot
This eruption would have been quite anecdotal in normal times; events like this can appear every few weeks when the Sun is approaching its peak of activity, as it is right now. Moreover, there is no indication that it generated an EMC that could threaten the Earth. What makes it quite unique, however, is that it was not an isolated case.
Indeed, the sunspot that gave birth to this eruption has already been talked about recently. Last Thursday, it had already produced a first violent X1.2 class eruption. Astronomer Tony Phillips, who wrote the review on SpaceWeather.com, even describes it as ” overactive “.
There is therefore a good chance that this task will continue to play its part. However, by the end of the week, the rotation of the sun will aim this electromagnetic gun straight at the Earth. Fortunately, according to the specialist, there is virtually no chance that this particular task will generate a devastating CME at this time.
Good news, because the most violent solar storms can put a large part of the earth’s electrical installations out of service in the blink of an eye. This would therefore have terrible consequences for humanity. To be convinced of this, just look at the Carrington Event, the most intense solar storm ever documented (see our article).
The star continues to rise
Astronomers are therefore particularly vigilant. Because right now, the Sun is precisely in the ascending phase of its eleven-year cycle of activity. This means that until the peak of this cycle, expected in 2025, more and more sunspots will appear on its surface. Mechanically, it will therefore generate more solar storms which are likely to be more and more intense, with all that this implies for humanity.
For the record, we are already seeing concrete manifestations of this increase in activity. Indeed, yesterday’s eruption further destabilized the solar magnetic field, triggering a kind of chain reaction. Astronomers observed five more consecutive flares in 90 minutes. A very rare situation that Phillips compares to the explosion of a batch of popcorn.
All this information will be of interest to specialists. They will use it in particular to improve the predictive models which make it possible to anticipate these eruptions and their consequences. But as it stands, humanity would still be unable to protect itself against a large-scale CME. It will therefore be necessary to knock on wood so that our providential star does not make too many whims as it approaches its peak of activity.