Ionosphere

High above the weather, sunlight strips electrons off air molecules, creating a layer of charged gas. This is the screen the aurora is projected onto — and the layer that bends radio waves around the planet.

The ionosphere is the partially ionized region of the upper atmosphere (D, E, and F layers) produced mainly by solar EUV and X-ray ionization. Auroral particle precipitation adds ionization and drives strong electrojet currents, perturbing radio propagation and GPS signals during storms.

Auroras live in the ionosphere — and the same storms that paint it green can disrupt GPS accuracy and HF radio, which is why agencies monitor it.