... Islands in the Photosphere . ... Credit: Gunther Groenez Explanation: Awash in a sea of plasma and anchored in magnetic fields , sunspots are planet-sized, dark islands in the solar photosphere , the bright surface of the Sun. ... In this sketch from March 6th 2001, astronomer Gunther Groenez has faithfully recorded the intriguing shapes and shades of major visible sunspot groups and labeled them according to their NOAA active region number . ... Publications with keywords: sunspot - Sun . ...