On the evolution in history of the concept of the auroral oval



It is shown in this review that the concept of auroral arcs forming one or more complete rings encircling the polar cap was very well accepted in the 18th century. This idea was elaborated further throughout the 19th century but then disappeared from the scientific scene for almost 80 years owing to the promotion of the auroral zone as a better frame of reference in auroral research. It is pointed out that the auroral zone was a dead end more influenced by the prevailing ideas of the last century than a product of profound physical reasoning. Finally, the importance of historical reviews in the field of science is stressed to learn to appreciate the often well-developed ideas of our predecessors and thereby avoid long periods of wandering in darkness, as had happened in the auroral zone.