The Sun is currently in a phase of intense activity which reminds us that without giving in to catastrophism, we must remain humble in the face of its whims.
The sun is currently experiencing a fairly intense period of activity as it approaches the peak of its activity cycle. Several large series of particularly violent solar flares have been documented recently (see our article). During the Easter weekend, one of them got itself noticed in the wrong way by causing a “radio blackout” in several places around the globe.
Very briefly, solar flares are neither more nor less than a large emission of particularly intense light. But they can also be associated with what are called coronal mass ejections. During these events, material made up of charged particles is catapulted at high speed in a specific direction.
Sometimes these eruptions can shoot straight for Earth. But fortunately, our planet has its own shield, namely the Earth’s magnetic field. This flow of solar plasma therefore crashes at the level of the upper atmosphere, which can sometimes give rise to auroras.
But if they have no concrete consequences the majority of the time, the most powerful of them can still have perceptible effects. Not directly on humans, but on electrical installations and electronic equipment. And that’s exactly what happened last month, and then over the Easter weekend.
X-class solar flares
“Airmen, sailors and radio operators have seen unusual propagation effects at frequencies below 30 MHz” in America, reports the specialized site SpaceWeather.com Wednesday, March 30, a few hours after the event in question. And at Easter SpaceConnect also reported similar events in Southeast Asia and Australia.
Fortunately, no accident is to be deplored following this incident; no ships have sunk, and no planes have crashed. But if this projectile succeeded in piercing the magnetic shield of the Earth, it is because it was particularly intense.
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“.
This letter is accompanied by a number which designates the size of the eruption in this category. The higher the number, the more violent it is. Note that this is a logarithmic scale, like the Richter scale which classifies earthquakes. This means that the power does not increase linearly with each level, but increases tenfold!
Here it was class eruptions respectively X1.3, then X1.1. We therefore had to deal with two events that were certainly very powerful, but of relatively moderate amplitude. And that’s good. Because History has already shown us that the scenario could have been much harsher, even potentially catastrophic. To illustrate this, we can look at the most violent solar storm in history, called Carrington Event in homage to the English astronomer who studied it.
A well-deserved booster shot
The event took place in 1859. Around this time, Carrington spotted abnormally large sunspots. Continuing to observe them, he eventually spotted two extremely intense flashes; without knowing it, he had just witnessed live the biggest solar flare ever documented.
When it hit Earth 17 hours later, it began by causing absolutely spectacular auroras that lit up the sky to the Caribbean, whereas they are usually confined to the polar regions. Some observers of the time even reported that it was possible to read one’s newspaper in the middle of the night, just by the light of the dawn!
The spectacle must have been absolutely breathtaking… but we can also say without the slightest doubt that humanity had a narrow escape. Because the least we can say is that this event would have had very, very different consequences if it had taken place today. Indeed, a 2004 study has since deemed the Carrington Event to be a class solar flare… X10.
This is an absolutely colossal figure, and it suffices to recall the analogy with the Richter scale to be convinced of this; everyone still remembers perfectly the terrifying assessment of the last two earthquakes to have reached a score of 9 (Sumatra in 2004 and Sendai in 2011) on this scale. The video below, which compares a simulation of this event with data from a moderate eruption in 2006, helps to appreciate the incredible magnitude of the particle flux.
Suffice to say that in 1859, this solar wind behaved like a real cosmic ram launched at full speed towards our planet. On impact, he temporarily depressed the earth’s magnetic fieldwhich had the effect of reducing the protection against ionized particles from the solar wind… with all that this implies for electronics.
The telegraph network was badly damaged with numerous spontaneous fires throughout the network; many operators were even victims of violent electric shocks. And yet, in 1859, electrical installations still much less developed than today; the telegraph itself was only about twenty years old. Imagine the consequences of such a scenario today…
A very real risk for infrastructure and equipment
It’s a pretty terrifying prospect for many reasons. The first is that electricity has become not only ubiquitous, but also essential to civilization as we know it. If the network and in particular certain satellites or critical computer systems were damaged on a large scale, it could result in chaos never seen before in our modern society.
This could cause problems in critical infrastructures. Fortunately, the actors involved are doing everything possible to protect them from such an eventuality. But the risk would still be considerable for power plants, including nuclear ones, hospitals, communication networks, health services such as water treatment, logistics chains that manage the supply of resources including food, etc.
The other concern is that these eruptions of ce kind are not a statistical anomaly which occurs every few million years. Quite the contrary; even on the scale of a human life, it is a very real possibility. A reality that came to our minds in 2012, when a new event of this type occured.
Fortunately, the coronal mass ejection did not approach Earth; but scientists who have taken an interest in the question have felt that it might have been necessary years to recover if she had gone in our direction. And today, this sword of Damocles still hangs over our planet. Therefore, from many programs are already working to develop countermeasures.
Several approaches are being explored to protect our infrastructures from an event of this type, but for the moment, humanity seems relatively unprepared to respond to an incident of this type. Without panicking unduly, we will therefore have to hope that our star does not make too many whims as it approaches the next peak of solar activity, expected between 2023 and 2026.