What causes the displays of lights called auroras?
interactions between charged particles from sun and earths atmosphere
The displays of lights called auroras are caused by interactions between particles from the Sun and the Earth's magnetic field.
To understand this phenomenon in more detail, here's an explanation of the underlying process:
1. Solar wind: The Sun continuously emits charged particles in the form of solar wind. This stream of particles, mostly electrons and protons, travels through space towards the Earth at high speed.
2. Earth's magnetic field: The Earth has a protective magnetic field surrounding it, which extends into space. This field deflects many of the charged particles present in the solar wind.
3. Van Allen radiation belts: Some of the charged particles from the solar wind get trapped in the Earth's magnetic field, forming two doughnut-shaped regions called the Van Allen radiation belts.
4. Solar particles interacting with the magnetic field: When solar particles reach the Earth's magnetic field, they can become trapped and guided along the field lines towards the magnetic poles (north and south).
5. Collision with atmospheric particles: As the solar particles move towards the poles, they collide with atmospheric particles, mostly oxygen and nitrogen atoms. These collisions cause the atmospheric particles to become excited and gain energy.
6. Light emission: When the excited atmospheric particles return to their normal state, they release the excess energy in the form of visible light. The colors of the auroras depend on the type of atmospheric gas involved and the altitude at which the collisions occur. Oxygen produces green and red auroras, while nitrogen produces blue and purple auroras.
That's how the interaction between solar particles, the Earth's magnetic field, and atmospheric particles leads to the beautiful displays of lights known as auroras.