ABSTRACT
Aurora or polar lights must have been observed from early times, since they are often strikingly brilliant. There are many legends about aurorae. In Norse mythology, the aurorae represented reflections from the shields of the Valkyries; in Denmark and Sweden it was said that aurorae came from an active volcano in the far north, put there by the gods to provide humanity with light and warmth. Of course the ancients had no idea of the real nature of aurorae. The connection between aurorae and electrical discharges goes back to a suggestion made by Edmond Halley in 1716; he linked auroral displays with discharges associated with the Earth’s magnetic field. The sunspot–aurora connection was refined in 1870 by E. Loomis of Yale, and in 1872 by the Italian astronomer G. Donati, following a major display on 4–5 February of that year. ‘Auroral displays were frequent and bright during July and August.
