iss073e0780439 (Sept. 2, 2025) --- A diffuse aurora glows above Earth's horizon over Canada as its red and green hues shimmer like neon lights—an effect created by excited oxygen atoms high in the atmosphere. The city lights of the U.S.-Canadian Pacific Northwest (toward upper right) trace the continent eastward. The red aurora is produced by high-altitude oxygen atoms (~300 km), while the green glow comes from lower-altitude oxygen (~100 km), both excited by energetic electrons guided into the atmosphere by Earth's magnetic field during solar activity.