Solar Prominences/Filaments

surface of the sun as observed from outside regions). (See fig. 1-2). Solar Prominences/Filaments Solar prominences/filaments are injections of gases from the chromosphere into the corona. They appear as great clouds of gas, sometimes resting on the Sun’s surface and at other times floating free with no visible connection. When viewed against the solar disk, they appear as long dark ribbons and are called filaments. When viewed against the solar limb (the dark outer edge of the solar disk), they appear bright and are called prominences. (See fig. 1-2.) They display a variety of shapes, sizes, and activity that defy general description. They have a fibrous structure and appear to resist solar gravity. They may extend 18,500 to 125,000 miles (30,000 to 200,000 km) above the chromosphere. The more active types have temperatures of 10,000°K or more and appear hotter than the surrounding atmosphere. Sunspots Sunspots are regions of strong localized magnetic fields and indicate relatively cool areas in the photosphere. They appear darker than their surroundings and may appear singly or in more complicated groups dominated by larger spots near the center. (See fig. 1-2). 1-4 AGf0102 SOLAR PROMINENCES PLAGE FLARE SUNSPOTS (FILAMENTS) Figure 1-2.—Features of the solar disk.