Northern Lights: The typical phenomenon of the polar arc will once again be observable in France tonight

Les amateurs de photographie ont ainsi une chance d’immortaliser ce phénomène naturel spectaculaire (illustration). MAXPPP – IMAGO/Ingo Wächter

A powerful geomagnetic storm of the Sun is underway, so the northern lights should extend to low latitudes and be visible in France.

According to the American weather service SWPC, a geomagnetic storm began on July 29 and should continue until at least August 1, reports Les NumériquesThis event offers the possibility of observing the northern lights up to approximately 50° north latitude, covering in particular the northern half of France. Photography enthusiasts thus have a chance to immortalize this spectacular natural phenomenon.

“There is a chance of more intense than normal northern lights this week, Wednesday and Thursday”, estimates Olivier Katz, space weather forecaster at the Operational Center of meteorology of the Alps space with franceinfo. But the phenomenon "will not be comparable" to that of May 10, which had allowed the formation of magnificent northern lights visible in the four corners of France.

Solar flares

The occurrence of this geomagnetic storm is not surprising, as the Sun is currently at its peak of activity, which frequently results in solar flares. Already, on May 11 and 21, auroras were observed at lower latitudes.

This weekend, a series of powerful solar flares were emitted from the Sun, accompanied by several plumes of plasma and magnetic field, known as coronal mass ejections (CMEs). The first two ejections merged to form a “cannibalistic CME”, and at least two more followed. These ejections are expected to reach Earth between July 30 and early August 1, although exact dates may vary.

When these CMEs hit Earth, they compress the auroral oval, which is centered on the magnetic poles and defines the area where auroras can be observed. Usually this area is restricted to the polar regions, but when compressed by CMEs, the oval extends towards lower latitudes, allowing the observation of aurora in unusual locations .

It is still difficult to predict the exact intensity of the auroras during this period, but they will probably be less bright than the spectacular ones in May. However, they should be sufficiently visible to observers located around the 50th parallel.

In more temperate regions

This period of intense solar activity offers a rare and valuable opportunity to observe the Northern Lights in more temperate regions, including the northern half of France, indicates our colleagues. Photographers and enthusiasts of natural phenomena can hope to capture these magnificent celestial lights over the coming days.

"If we ever see something, it could correspond to a luminous grayish spot, visible to the naked eye, at eye level. horizon, to the north. In the photo, with a 4 to 7 second pause, we can see reddish pillars appear", underlines the specialist.