Aurora borealis. 19th-century artworks of two aurora borealis displays (northern lights). The one at top was observed from Bossekop, Norway, on 9 January 1834. The intensity of the light exceeds that of the first magnitude star shown. At bottom is an aurora observed on 19 October 1726 at Breuille-Pont. The aurora is a coloured polar light display. Charged particles from the Sun, drawn by Earth's magnetic field to the polar regions, collide at high altitudes with gas molecules and atoms, causing them to emit light. Artwork from 'Traite d'electricite et de magnetisme' (1855) by French physicist Antoine Cesar Becquerel (1788-1878).