IMAGES TO ACCOMPANY: January 13, 2008: Sitting on a Sunspot
Sunspots appear as dark patches on the "surface" of the Sun. This sequence of Solar photographs shows how Sunspots appear to travel across the face on the Sun. Astronomers observed this sunspot procession and deduced the Sun's rotation period.
(Images courtesy of NASA/SOHO/Spaceweather. Images captured 8/12/06 - 08/16/06)
A closer view of a Sun spot. The dark inner area, called the umbra, is surrounded by the penumbra.
(Images courtesy of NASA)