An aurora is a natural light display in Earth's upper atmosphere, caused by charged particles from the Sun colliding with atmospheric atoms. The collisions excite oxygen and nitrogen, producing colours including green, red and purple. Auroras occur mainly in high-latitude regions: the Arctic aurora is called the aurora borealis or the northern lights, while its Antarctic counterpart is the aurora australis or the southern lights. They can also occasionally appear at much lower latitudes. Forms of aurora include glows, patches, arcs, rays and coronas, consistent with auroras being shaped by Earth's magnetic field. This photograph shows an aurora borealis over Tuntorp in Lysekil Municipality, Sweden, caused by a geomagnetic storm in May 2024.

Photograph credit: Ann-Sophie Qvarnström