Polar aurora: what is it?

The auroras polar are mainly visible at the highest latitudes of the terrestrial globe:

When the activity of the Sun is at its highest level (the solar cycle lasts on average eleven years), it is possible to observe it up to mid-latitudes such as those of France, even sometimes as far as Spain and Morocco. .

The polar auroras: explanation

It is the solar wind which is at the origin of the polar aurora. Highly energetic particles (electrons and protons) expelled at an average speed of 400 km/s in all directions of the Solar system are, for the most part, deviated from our atmosphere speak earth’s magnetic field. However, a part manages to pass through the weak points at the poles.

It is their interaction with the different atoms and molecules of the’ionospheremainly theoxygen and nitrogen, at altitudes between 400 and 100 km, that comes from their coloration:

• from green to red for oxygen;
• from pink to purple, from blue and also from red for nitrogen.

All these nuances also depend on theenergy solar wind and altitude.