How Auroras Form
Planetary Astronomy and Physics
The sun constantly emits a stream of charged particles called the solar wind. When these particles reach the Earth, they are deflected by its magnetic field and directed toward the polar regions. As these charged particles collide with the molecules in the Earth's atmosphere, they transfer energy to them, causing the molecules to emit light. This causes the beautiful light display we see in the sky, known as auroras.
The type of gas in the atmosphere and the altitude at which the collisions occur determine the color of the auroras. For example, oxygen atoms produce a green or red aurora, while nitrogen produces a blue or purple aurora.
Auroras occur most frequently during periods of high solar activity, such as during a solar flare or coronal mass ejection. These events can send many charged particles toward the Earth, resulting in more frequent and intense auroras.
