Spörer minimum

The Spörer minimum is a period of low sunspot activity that lasted from about AD 1420 to 1570, based on evidence such as carbon-14 in tree rings and records of auroral activity. The Spörer minimum, and the similar Maunder minimum, coincide with a period of low global temperatures known as the Little Ice Age. It was discovered by the American solar physicist John Allen Eddy (1931–2009) who named it after Gustav Spörer.