A gigantic sunspot located directly in front of the earth challenges astronomers because of its rapid growth.
For a few days, astronomers have been following the evolution of a gigantic sunspot with very particular attention; it is growing at a maddening rate and will remain directly facing the Earth for a few more days.
These sunspots are dark areas on the surface of the Sun. They appear as a result of variations in the magnetic field. If researchers are watching them closely, it is because they are the scene of violent solar flares.
These are often associated with a phenomenon called “coronal mass ejection”, or CME. Very briefly, it is a bubble of charged particles (or, more precisely, of plasma) which finds itself catapulted in a precise direction by the internal activity of the star.
The Earth directly in sight
When the sunspot in question faces the Earth directly, as is the case here, the planet is therefore directly exposed to these EMCs. And it is precisely this eventuality that motivates the monitoring of sunspots. Because these EMC can have very important consequences.
The majority of them are stopped dead by the earth’s magnetic field, which acts as a shield. But the most powerful of them can still have noticeable effects. Not directly on humans, but on electrical installations and electronic equipment. This is exactly what happened around the Easter weekend, when moderate solar flares caused a few radio blackouts on Earth (see our article).
A sunspot 2.5 times larger than our planet
And in some particularly rare cases, the situation even becomes critical. Indeed, exceptionally intense EMCs are quite capable of frying half of the world’s electronic infrastructure in a few moments, with all the catastrophic consequences that entails.
An X-class solar flare caused a radio blackout on Earth
Suffice to say that the astronomers had to swallow a good shot when they found that the sunspot in question, called AR3038, was growing very quickly. “Yesterday AR3038 was big. Today it is huge. This fast-growing sunspot doubled in size in just 24 hours”, explain the authors of the report on spaceweather.com. But fortunately, astronomers consider this task to be less threatening than it seems.
No X-class eruption to be expected
Solar flares are classified using a somewhat particular nomenclature. It begins with a letter (A, B, C, M or X) which designates the power category. A denotes the smallest; on the contrary, X designates the most violent eruptions. The official definition explains that they have the potential to “trigger planet-wide radio blackouts and prolonged radiation storms“.
In the case of AR3038, specialists estimate that it could give birth to a class M solar flare, which corresponds to a medium intensity. There is therefore no no risk of radio blackout like last April. The possibility of an X-class solar flare, the only truly ominous type on our scale, seems entirely ruled out.
On the other hand, this event shows once again that the Sun is particularly active at the moment. Astronomers know that it is currently in the ascending phase of its 11-year cycle; they therefore expected significant activity. But even in this context, the spring of the sun has been extremely eventful.
The number of sunspots is an excellent indicator of this dynamic; and over that period, astronomers have spotted almost twice as many as expected. We will therefore have to knock on wood as we approach the next peak of solar activity, expected between 2023 and 2026.