The northern lights club because of what state of matter?

The northern lights, or auroras, are primarily caused by interactions between charged particles from the sun and the Earth's magnetic field, which occur in the atmosphere. These interactions primarily happen in the ionosphere, a region of the atmosphere where gases are ionized, making it a plasma—a state of matter where electrons are separated from their nuclei. This ionization leads to the emission of light, creating the stunning displays of the northern lights.