Behind the beauty of the Northern Lights, danger

Behind the beauty of the Northern Lights, danger
Behind the beauty of the Northern Lights, danger

Normally limited to high latitudes, northern lights and southern regions have recently dazzled a large number of Earthlings, even the Swiss. But for those responsible for protecting terrestrial installations vulnerable to solar storms, the spectacle was less attractive and its causes still threatening. “We need to understand that there is danger behind this beauty,” says Quentin Verspieren, security program coordinator at the European Space Agency (ESA).

Same story with Mike Bettwy, of the American Center for Space Weather Prediction, rather “focused on the potentially harmful impacts” of 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, although it will be a few weeks or months before satellite companies reveal any damage.

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, thereby 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”, says Alexi Glover, space weather coordinator at ESA.

Solar activity is “anything but over,” according to this expert, although 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.

Geomagnetic storms create an electrical charge that fry satellite circuits and overload power grids. Astronauts are particularly at risk from high doses of radiation, with the ability to protect themselves from them in a special area of ​​the international space station.

Radiation accompanying a geomagnetic storm can also potentially “pass through the fuselage” of an airliner near the North Pole, according to Mike Bettwy. Airlines sometimes change their aircraft routes in the event of an extreme storm.

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