An "extreme" solar storm, the first of this magnitude in over 20 years, began to hit Earth Friday evening. Stunning auroras are a spectacular aspect of it, but beware of some of its harmful effects which could damage certain technologies and facilities...
Conditions related to a level 5 geomagnetic storm, the maximum level on the scale used, were observed Friday evening, announced the American National Oceanic and Atmospheric Administration (NOAA).
"GPS, power grids, spacecraft, satellite navigation, and other technologies may be affected," the agency added. This storm is caused by the arrival on Earth of a series of coronal mass ejections from the Sun. It involves "explosions of energetic particles and magnetic fields emanating from the sun," explained Shawn Dahl from the Space Weather Prediction Center (SWPC) affiliated with NOAA, during a press conference Friday afternoon.
The last event reaching this level 5 dates back to October 2003, an episode dubbed "the Halloween storms," the agency noted. At that time, power outages occurred in Sweden and transformers were damaged in South Africa, it detailed.
The storm is expected to continue throughout the weekend, with the arrival of additional coronal mass ejections, NOAA added. The first of these ejections, "very strong," reached Earth Friday around 4:30 PM GMT.
The Sun is currently near its activity peak, according to a cycle that recurs every 11 years. These coronal mass ejections, of which at least seven directed towards Earth have been observed, originate from a sunspot about 17 times the diameter of the Earth. They travel at several hundred kilometers per second.
Besides potential disruptions, these significant solar storms generate impressive auroras, sometimes much further south than the regions where they are usually observed.
Photos taken in Europe have begun circulating, taken for example in London. "We just woke the kids up to watch the auroras in the garden!" said Iain Mansfield, a political advisor living in Hertford, England, to AFP.
Satellite operators, communications, and the power grid in North America have been notified to take precautionary measures, said Shawn Dahl. He recommended that residents equip themselves with batteries or potentially generators, as with any other storm warning.
Power operators have worked over the past ten years to better protect their networks, however, Rob Steenburgh, a scientist at the SWPC, reassured.
Effects will only occur on high-voltage lines, not at the individual level, and systems akin to circuit breakers exist. He also indicated that his agency was in very regular contact with NASA, which ensures the safety of astronauts in the International Space Station (ISS), more vulnerable to solar radiation.
A radiation alert has also been issued, but only at a level 1 out of 5 on the scale, so it does not currently cause concern. Billionaire Elon Musk, whose Starlink internet network has about 5,000 satellites in low Earth orbit, was reassuring. "Starlink satellites are under a lot of pressure, but so far they're holding up," he assured on his social network, X. Regarding air traffic, the American Federal Aviation Administration (FAA) said "not to expect significant consequences." Geomagnetic storms can disrupt navigation tools and high-frequency radio transmissions, however, the American aviation regulator explained, adding that it had advised airlines and pilots to "anticipate" possible disturbances.
This type of storm first affects latitudes around the poles, explained Mathew Owens, a professor of space physics at the University of Reading to AFP. But "the stronger the storm, the further it goes down in terms of latitude," he added. In the Southern Hemisphere, countries like Australia or New Zealand closely monitor these types of situations, explained Shawn Dahl.
In the United States, auroras should be observable over most of the northern half of the country, according to NOAA, and perhaps as far south as Alabama or northern California. "If you are in a place where it's dark, cloudless, and with little light pollution, you could see quite impressive auroras," said Rob Steenburgh.
"It's really the gift of space weather." The most significant solar storm ever recorded occurred in 1859, according to NASA. Also known as the Carrington Event, it severely disrupted telegraph communications.