An intense solar storm, a phenomenon described as “very rare,” has been affecting Earth since Friday, May 10, and is expected to persist through the weekend. For the first time in almost twenty years (2005), a level 4 geomagnetic storm alert, on a scale of 5, was issued by the American Space Weather Prediction Center (SWPC).
“A series of coronal mass ejections, which are explosions of energetic particles and magnetic fields from the Sun, are directed towards the Earth,” explained Shawn Dahl of this center attached to the Earth at a press conference. National Oceanic and Atmospheric Administration (NOAA).
The first of them, “very strong”, reached Earth on Friday around 6:30 p.m. (Paris time), the agency said. “There could be impacts on infrastructure,” Shawn Dahl said. “We have notified all the operators that we work with, such as satellite, communications and of course the power grid operators in North America,” he added.
The Sun is currently close to its peak of activity, according to a cycle that returns every eleven years. These coronal mass ejections – at least seven of which have been observed directed towards the Earth – come from a sunspot approximately sixteen times the diameter of the Earth. They move at several hundred kilometers per second.
A radiation alert without worry for the moment
Shawn Dahl recommended that residents equip themselves with batteries or potentially generators, as with any other storm warning. But electricity operators have worked for ten years to better protect their networks, reassured Rob Steenburgh, scientist at SWPC. The effects can only occur on high voltage lines, not in individuals, and systems comparable to circuit breakers exist.
GPS signals could also be affected, he said. He also said that his agency was in very regular contact with NASA, which ensures the safety of astronauts in the International Space Station (ISS), who are more vulnerable to solar radiation. A radiation alert has also been issued, but only 1 on a scale of 5, so not causing concern at this time.
Regarding air traffic, the United States Civil Aviation Agency (FAA) said “do not expect significant consequences”. Geomagnetic storms can disrupt navigation tools and high-frequency radio transmissions, however, the American air regulator explained, adding that it advised airlines and pilots to “anticipate” possible disruptions.
The vigilance notice precedes the alert, when the storm is actually observed. Smaller geomagnetic storms reaching Level 4 have been observed in recent years, most recently in March. But then it only lasted a few hours. The current event should be of a completely different magnitude, although still smaller than the solar storm of 1859, the largest recorded, according to NASA. Also known as the Carrington event, it corresponded to a level 5 event, and had severely disrupted telegraph communications.
“The Gift of Space Weather”
This type of storm particularly affects the northern and southern latitudes, around the poles, Mathew Owens, professor of space physics at the University of Reading, explained to Agence France-Presse. And “the stronger the storm, the lower it goes in terms of latitude,” he explained.
In the southern hemisphere, countries like Australia and New Zealand also closely monitor this type of situation, explained Shawn Dahl. The event should therefore generate northern and southern lights, including in regions where they are not usual. In the United States, northern lights should be able to be seen over most of the northern half of the country, and perhaps as low as Alabama or northern California, according to NOAA.
“If you’re in a place where it’s dark, cloudless and with little light pollution, you might see some pretty impressive northern lights,” Rob Steenburgh said. And that truly is the gift of space weather. »
