Northern Lights: will we still be able to see them in France tonight?

AURORA BOREALIS. Good news, it seems that the solar storm could offer a new opportunity to see the Northern Lights this Friday, May 31, 2024 in the evening.

[Mise à jour le 31 mai 2024 à 19h57] Remember, on the nights of May 10 to 12, impressive northern lights set the French sky ablaze, offering many amateur or professional photographers the opportunity to immortalize the splendid colorful ballet of ephemeral lights, produced of the encounter between solar particles and the gases present in our atmosphere.

For those who thought they had missed the opportunity to observe the magical spectacle, it appears that the same extreme solar storm that hit Earth a few weeks ago, producing these northern lights, would still be active this weekend! If nothing is certain, we still advise you to observe the sky from the beginning of the night, favoring a location far away from light pollution, provided that the sky is perfectly clear.

The mechanism of the aurora borealis, discovered at the beginning of the 20th century by meteorologists, is the result of intense solar activity. When the sun emits waves of particles highly charged with energy which come into contact with the magnetosphere (space surrounding the Earth beyond the ionosphere)the interaction causes this magnificent luminous phenomenon.

Where to see the Northern Lights in France?

France is a country located largely south of the Arctic Circle. It is for this reason that the probability of observing an aurora borealis is extremely low. However, this phenomenon occurs from time to time as will perhaps be the case this Friday, May 31, 2024 because the earth’s magnetic field has been shaken by solar winds!

This type of event is often limited, however, to regions located in the north of the country such as the departments of Pas-de-Calais, Brittany, North and Alsace. Near cities, the Northern Lights are very difficult to observe with the naked eye and are generally only visible on camera images.

What are the conditions for observing the Northern Lights?

To fully enjoy the Northern Lights, it is recommended to move away from sources of light pollution. So look for a location located away from urbanized areas. Watch the weather to favor a night when the sky is clear or the clouds are not too thick. Finally, you can monitor the Kp index which will allow you to know the probability that an aurora borealis will occur.

How to predict the Northern Lights?

It is impossible to accurately predict the date and time of the next aurora borealis in any given location. On the other hand, certain indices make it possible to know the probability of this type of event occurring. For this, we are generally interested in the Kp index which provides information on the intensity of the magnetic disturbances experienced by the Earth. The planetary Kp index, updated every three hours, is available on the website SpaceWeatherLive.

To know if the Northern Lights are expected, it is generally advisable to follow the evolution of this indicator which reflects the occurrence ofsolar flares. These latter emit solar winds which can, if they cross the trajectory of the Earth, be the origin of spectacular northern lights depending on their intensity.

What is the Northern Lights?

The Northern Lights are atmospheric phenomena that can be observed at the Earth’s poles. They appear as luminous clouds that appear to dance in the night sky. Although they have been interpreted in different ways in history and according to folklore, these luminous veils are in reality linked to the activity of the Sun which regularly bombards the Earth with energetic particles. When these reach the earth’s atmosphere, they interact with the gases that make up our atmosphere, causing these celestial manifestations.

What causes the Northern Lights?

The Sun emits electrically charged particles in all directions, including toward our planet. The latter is protected from these particles by the Earth’s magnetic field, a real invisible shield generated by the movements of the Earth’s liquid core. When the solar wind encounters this protective barrier, it deforms, but generally prevents particles from entering the atmosphere.

However, it happens that solar winds are more violent than usual. This is particularly the case during very intense solar flares. In this case, the magnetic field is disturbed and the particles emitted by the Sun pass this invisible barrier. It is the encounter of these particles with the gases of the earth’s atmosphere which generates the northern and southern lights.

When energetic particles emitted by the Sun enter the atmosphere, they encounter and collide with the particles that make up the gases in the upper atmosphere. “Electrons and protons then excite the atoms which constitute these gases and, through a phenomenon called ionization, transmit an electric charge to them. It is by returning to their initial state that the atoms in the earth’s atmosphere will release light energy , in the form of photons” explains the magazine Geo. It is therefore these electrical interactions which generate luminous and colored bands above our heads.

What explains the color of the Northern Lights?

Sometimes green, sometimes red or pink, the Northern and Southern Lights are adorned with varied colors and can offer very different shows from one day to the next. “At the moment of collision, these particles emit light. The colors differ depending on the atoms stimulated, from red to green via violet or yellow. The gradients can represent all the shades of the chromatic spectrum” explains the magazine National Geographic. The color of an aurora borealis depends on the altitude at which it forms as well as the nature of the gases present at that height.

Thus, when they form at low altitude, around 100 kilometers, the auroras can appear in the form of a green veil in the presence of oxygen, pink or red in the presence of nitrogen or even blue or purple in the presence helium or hydrogen. At higher altitudes, around 300 to 400 kilometers, oxygen can also give a red tint to the glow.