The aurora borealis — the northern lights — begins with the Sun. It constantly sends out charged particles, the solar wind. When they reach Earth, our planet's magnetic field funnels some of them toward the poles.

There they collide with gas in the upper atmosphere, about 100 to 300 kilometres up, and make it glow. Oxygen produces the common green; at higher altitudes it can glow red; nitrogen can add blues and purples.

This photograph was taken over Eielson Air Force Base, near Fairbanks, Alaska, one of the best places on Earth to see the lights. After a big solar storm, auroras can be seen much farther south than usual — and many people saw them for the first time during the powerful storms of 2024.