Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense gases held in place by solar magnetic fields. Filaments are observed on the solar disk as dark structures as seen against the hotter chromosphere whereas prominences on the limb appear bright against the perspective of outer space. The scale sizes for prominences and filaments are typically many thousands kilometers. Solar observers typically view prominences and filaments in Hydrogen alpha (656.3 nm). Filaments are sometimes referred to as floccule (plural of flocculus). Prominences and filaments can rapidly form over a period of a day but then typically persist for several weeks and, in some cases, several months. At breakup the gases within these previously stable structures may be explosively released into space in the form of a coronal mass ejection (CME). Space weather operators have and continue to monitor the location and character of prominences and filaments as potential precursors on near-earth geomagnetic activity. (Browse image provided courtesy of http://www.greatdreams.com)