There are two main types:
* Aurora Borealis: This is the aurora seen in the Northern Hemisphere, often called the "Northern Lights".
* Aurora Australis: This is the aurora seen in the Southern Hemisphere, often called the "Southern Lights".
Here's how they form:
1. Solar wind: The sun constantly emits a stream of charged particles called the solar wind.
2. Earth's magnetic field: Earth has a magnetic field that acts like a shield, deflecting most of the solar wind.
3. Charged particles: Some of the charged particles from the solar wind get trapped in Earth's magnetic field lines.
4. Magnetic poles: These trapped particles travel along the magnetic field lines towards the Earth's poles.
5. Collisions: When the particles collide with atoms and molecules in the Earth's atmosphere, they excite those atoms.
6. Light emission: As the excited atoms return to their normal state, they release energy in the form of light, creating the auroras.
The colors of auroras vary depending on the type of gas that is being excited. For example, green is the most common color, caused by oxygen atoms. Red and purple can also be seen, caused by nitrogen molecules.
