Sujet DNL : Aurora Borealis

« Sujet DNL : Aurora Borealis Introduction : We are going to speak about northern light, these lights we can see in the pole north and south.

When we speak about auroral borealy, we should make the difference between auroral austral which comes out in the south pole and auroral borealy which comes out in the northern pole.

So we have little chance to see one in France or in equatorial or tropical countries.

It seems obvious but we have to be precise that you cannot see northern light when it’s not the night.

We have the best chance of seeing the aurora borealis at the north pole.

You must therefore go to the north of Scandinavia, the north of Russia, Islands, Greenland, the Canadian far north or Alaska.

They sometimes take strange forms, for example: a face and bird. This beautiful phenomenon is closely related to physics. Physical explanation : Auroral borealy are related to the activity of the sun.

The sun produces light but also produces an uninterrupted flow of electrically charged particles: electrons and protons.

Because of the reactions in the sun, the particles are ejected and propelled into space at a rate of 1 300 000 km/h: it forms what is called the solar wind.

The solar wind is made up of radioactive particles.

If its particles would enter the atmosphere there would be no life.

But thanks to the magnetic field of the Earth its particles bypass the Earth but do not enter the atmosphere.

This magnetic field deflects around 98% of the radioactive particles that continue their paths in space.

However a small percentage can penetrate the magnetic field.

Protons and neutrons with a lot of energy enter into a collision with the atoms that make up the high atmosphere.

This reaction releases a lot of energy in the form of light which creates northern lights. Color explanation: These beautiful lights that take shape between eighty and three hundred kilometers above us, can be blue red, green purple .

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