Evidence for a larger Sun with a slower rotation during the seventeenth century

Historical records suggest that during the seventeenth century the Sun was subject to an anomalous scarcity of sunspots (the Maunder minimum). By analysing a unique 53-year record of regular observations of the solar diameter and sunspot positions during the seventeenth century, the authors have shown for the first time that the solar diameter was larger and the rotation was slower during the Maunder minimum. This finding sheds new light on the dynamo mechanism, solar variability, and the consequent effects on terrestrial climate. (author)