The greatest sunspot activity ever recorded occurred during the 1957 maximum, with a mean Zurich Sunspot Number of 190.2. Despite the mercurial nature of sunspot size and number, sunspot location on the sun is not as random. Also, the early spots in a new cycle overlap in time with the last spots in the old cycle. Maunder also discovered that no sunspots at all appeared from 1645 to 1715, a period now called the Maunder minimum. Critics note that other factors, such as suspended volcanic aerosols, may also have affected global temperatures during that period.
Some prominences form giant coil shapes due to magnetic field lines.
Jean Dragesco Location, Location, Location Galileo studied sunspot location and movement and determined that the sun rotates on its axis . Amateur sungazers can duplicate these historic observations. Photograph or make a pencil sketch of the sun's disk every second or third day over a span of a month. Each successive sketch should show how sunspots appear to move as they change in size and shape. Several months of observation reveal that spots at different latitudes on the sun rotate at different speeds.