Something is happening to our Sun. On July 11, one of the regions of the solar atmosphere currently exhibiting sunspots came to the attention of observatories due to a sudden increase in its luminosity in the ultraviolet and X-rays. they were radio amateurs on both sides. of the Pacific Ocean, have your communications briefly interrupted.
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There had just been a sun burst. That is, a sudden emission of electromagnetic radiation and energetic particles located in a small region of the solar atmosphere. A region where, in addition, the magnetic field is particularly strong and complex.
On many occasions, a solar flare precedes a much more impressive event. The same magnetic field that generated such an eruption is twisting beneath the Sun’s surface, dragging huge amounts of solar plasma out of it and, like a cannon, blasting it at high speed into space. We are then talking about a coronal mass ejection. Unlike flare radiation (which reaches Earth at the speed of light, about 8 minutes), coronal mass ejections are made up of charged particles moving at a certain speed. This implies that they can take between a few hours and several days to reach Earth orbit.
And that’s how it ended up being. Different eruptions of moderate intensity continued to occur during the past week until, on July 15, one of them was accompanied by a spectacular ejection. Of course, with a particularity: this time, it is directed towards our planet. And we hope to be joined by her on July 21.
The story repeats itself
This isn’t the first time we’ve seen each other. Although today the physics of these phenomena is not fully understood, we are certain that their nature is mainly magnetic. And also that its appearance is not fortuitous: approximately every 11 years, our Sun experiences periods of strong magnetic activity (called solar maxima).
During these maxima, the frequency of these events is particularly high. And right now we are entering the maximum of the current cycle, the peak of activity of which should be reached throughout the year 2024.
The extension of a coronal mass ejection is often accompanied by striking auroras. However, the most global effects occur when it interacts with the call magnetosphere Terrestrial: sort of protective bubble that surrounds the Earth, in which the intensity of the Earth’s magnetic field is able to deflect the charged particles emitted by the Sun (solar wind). This allows, among other things, the Earth to preserve its atmosphere.
In contact with an ejection, the magnetosphere compresses and interacts with it by modifying its structure. Rapid variations in the Earth’s magnetic field produce induced electric currents wherever there are free electric charges (such as the ionosphere, one of the layers of our atmosphere). This in turn generates more complex magnetic fields that add to the Earth’s magnetic field.
This chaotic disturbance of the magnetic field is called a geomagnetic storm. And this, in turn, can disrupt radio and satellite communications. In the most extreme cases, even power outages.
Will there be power outages and communication issues?
Currently, the highest alert level published by the various space weather observation and forecasting services (such as the NOAA, Space Weather oh SOHO) are G1. This alert level corresponds to minor geomagnetic storms, with possible small fluctuations in the electrical network and a reduced impact on satellite operations. We shouldn’t be worried, should we?
The truth is, that might not have been the case. In September 1859, a geomagnetic storm caused by a coronal mass ejection caused the failure of telegraph networks in Europe and North America. The electrical currents induced in the cables reached such intensity that they caused fires in the receivers. There were even cases of electrocution by telegraphers. It was called Carrington eventby the astronomer who observed the eruption, Richard Carrington.
Back then, we were saved by our limited reliance on electronic systems. Today, we would not be so lucky: our hyper-technified society maintains a blind faith in the resilience of the communication networks on which our cell phones and our computers depend, something that could not be guaranteed in an event of such magnitude.
For now, the various attempts made by States to deal with this type of threat have been shy, uncoordinated and based on generalities. Our current situation is one of obvious vulnerability. And even if the frequency of these phenomena should not cease to increase in the years to come, it still seems to us to be a problem too foreign.
The question now is, will we have time to change our minds before the next Carrington event?
This article is from The Conversation. Read the original here.