She was notable for her remarkable intensity, but also for her amazing discretion; None of the monitoring services tracking these events detected the slightest warning sign before the stream of particles hit Earth’s magnetic field.
Solar storms are events that occur when the interaction of various solar winds causes an upheaval in the magnetic field. Under these conditions, a stream of high-energy particles can be catapulted from the star into a large plasma bubble; then we talk aboutcoronal mass ejection (CME)
Sometimes this radiation goes directly to our planet. It then collides with the Earth’s magnetic field, which acts as a shield against these electrically charged particles. But they don’t just hit back. They interact with gases in the upper atmosphere and this causes what is called geomagnetic storms. For reference, the most spectacular Northern Lights can be seen during these episodes.
Strongest geomagnetic storm in 6 years
It is the intensity of these disturbances that allows these episodes to be classified. This morning’s storm was rated G4. This ranks among the G5 storms that are strongest. That makes more than six years that the earth had never experienced such a powerful geomagnetic storm.
One might therefore expect that the many specialists constantly scanning the Sun would have discovered it very early. But exactly the opposite happened, because the disruption caught everyone unprepared.
© NOAA Space Weather Prediction Center
However, specialists knew that something was brewing. The US National Space Weather Service originally issued a warning on March 22nd. The agency had pointed out that class G2 solar storms, i.e. medium intensity, had to be expected. But nobody expected the violence of the phenomenon, because the warning signs were particularly discreet.
A rogue CME arrived without warning
To anticipate these phenomena, astronomers generally rely on observations of the solar corona. Very specific patterns appear when the magnetic field is disturbed and a solar storm hits. But in some cases, when the origin of the disorder is deeper, this visual signature can be extremely discreet, if not completely absent.
A surprising full coronal mass ejection solar prominence captured by astrophotographer Miguel Claro in July 2022. © Miguel Claro
You can then create what is called “Discrete CME” (or Stealth CME in English). As their name suggests, they are very difficult to detect before they reach Earth, a bit like the rogue waves feared by sailors. And that’s exactly what happened this morning.
This is a pretty worrying situation. When specialists are actively observing the sun, it’s not just about advancing abstract work that belongs to basic research. There are also very specific questions, because these particle streams are anything but harmless. This radiation not only creates breathtaking polar lights. If it is strong enough to suppress the magnetic field, it represents a very concrete threat to electronic systems.
The sun’s peak activity is fast approaching
Perhaps the best example to illustrate this danger is the Carrington event, the most intense solar storm ever documented. During this super-powerful solar flare in 1859, the particle stream was so intense that telegraph operators were electrocuted. Power lines also spontaneously caught fire (see our article below).
An X-class solar flare caused a radio blackout on Earth
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It is therefore easy to imagine what catastrophic consequences such an incident could have today. A similar storm could instantly bring down the entire global internet infrastructure. It would also include navigation satellites such as GPS and Gallileo systems, cellular networks…
Luckily, the storm this morning didn’t even come close to what happened in Carrington. But it was still powerful enough to wreak havoc. In particular, it generated a brief radio failure, but fierce. According to Space.com, Rocket Lab was forced to do the same postpone the launch of one of its rockets at the last minute. She feared that the on-board electronics had been damaged. SpaceX also went through a similar situation last March (see our article).
© NASA/GSFC
Suffice it to say that we must redouble our vigilance going forward. In fact, the Sun is currently in the ascending phase of its 11-year cycle. As we get closer to the peak of activity expected in 2025, the more frequent and violent the solar storms – and with them the discrete CMEs – will be.
Unfortunately, we currently have no way to protect our technology from a particularly intense CME. Therefore, while waiting for researchers to discover a life-saving trick, it will be necessary be humble in the face of the whims of our starwhile keeping her fingers crossed that she’ll be lenient in the years to come.
