“A danger behind the beauty”: what could be the impacts of the Northern Lights and solar storms ?

Des aurores boréales au Havre le 11 mai 2024. MAXPPP – Quentin Déhais

Normalement limitées aux latitudes élevées, des aurores boréales et australes ont récemment ébloui un grand nombre de Terriens avec un festival de couleurs dans le ciel nocturne jusqu’au Mexique ou encore le sud de l’Europe et de l’Afrique.

A dangerous spectacle ? For those charged with protecting terrestrial installations vulnerable to solar storms, the spectacle was less attractive and its causes still threatening. "We We must understand that there is a danger behind this beauty", explains to AFP Quentin Verspieren, coordinator of the space security program at the European Space Agency (ESA).

Same story with Mike Bettwy, of the American Space Weather Prediction Center, rather "focused on potentially harmful impacts& ;quot; solar storms. At the origin of the Northern Lights, they can also fry electrical networks and satellites or expose astronauts to dangerous radiation.

The Northern Lights that appeared on May 11 and 12 were caused by the most powerful geomagnetic storm since the "Halloween storms", in October 2003, which caused power outages in Sweden and damaged networks in South Africa.

This time, the damage was apparently less according to Mike Bettwy, although it will be a few weeks or months before the satellite companies reveal any damage. There have been a few stories of automated American tractors stopping when their GPS guidance system went off the rails.

High risks of geomagnetic storms

Geomagnetic storms occur when streams of electrically charged particles are expelled from the Sun's surface and reach the magnetosphere, the Earth's magnetic field. These particle flows are particularly intense during coronal mass ejections, very strong flares occurring near sunspots. Like the one at the origin of the latest events and a particularly strong eruption last Tuesday.

With the rotation of the Sun this spot is located near the edge of the star, further deflecting the flow of particles from possible eruptions. But in about two weeks, it will face Earth again. And in the meantime a new spot "is appearing now", and could lead to "intense activity in the coming days", Alexi Glover, space weather coordinator at ESA, told AFP.

Solar activity is "anything but over", according to this expert, even though he It is difficult to predict the severity of possible eruptions or whether they will cause the Northern Lights. Astronomers only know that the Sun is approaching a peak of activity in its eleven-year cycle. The risks of a new geomagnetic storm are therefore at their highest "between now and the end of next year", according to Mike Bettwy.

What are the threats?

Geomagnetic storms create an electrical charge that fry satellite circuits and overload electricity networks. A phenomenon whose most famous and powerful example to date, the Carrington event in 1859, produced sparks in telegraph stations. With such power that some continued to operate without connection to the electrical network.

What if a geomagnetic storm of such force occurs again? Most countries have hardened their electricity networks, in order to avoid prolonged outages like in Sweden in 2003 or in Canada in 1989.

Mike Bettwy nevertheless recommends keeping a first aid kit to deal with a power outage of a day or two. With water supplies in case the sanitation plants are affected. Astronauts are particularly at risk of high doses of radiation, with the possibility of protecting themselves from it in a special area of ​​the international space station.

Radiation accompanying a geomagnetic storm can also potentially "pass through the fuselage" of a nearby airliner from the North Pole, according to Mike Bettwy. Airlines sometimes change the routes of their aircraft in the event of an extreme storm. Several space missions are in preparation to improve solar meteorology. And provide those responsible on Earth with more time to prepare for a severe event.