Weather Tidbits: How The Aurora Lights Form

This edition of Weather Tidbits will discuss how the aurora lights form. The process starts when charged protons and electrons emit from the sun. This can come from a solar flare or a coronal mass ejection. The ejected particles are carried through the solar wind. Eventually, these particles make it to the Earth. The Earth has a magnetic field because of its interior iron composition. This magnetic field is weakest in the polar regions and strongest at the equator. Thus, the particles get attracted to the polar regions. That is why the aurora lights are most visible in the polar regions. The strength of an ongoing geomagnetic storm determines how far south the lights will be visible from. Once the particles of protons and electrons encounter the atmosphere, collisions with various molecules occur. These collisions cause varying colors based on the height and type of molecule hit.

Oxygen molecules 200 km above the surface will form red auroras and green auroras between 100-200 km. Nitrogen molecules will form blue auroras between 100-200 km and pink auroras below 100 km.