High School Earth Science: Earth, Moon, and Sun - The Sun — Flashcards

Surface Features of the Sun    
The most noticeable surface features of the sun are dark spots known as sunspots. Sunspots are located where loops of the sun’s magnetic field break through the surface. This disrupts the smooth transfer of heat from lower layers of the sun, making sunspots cooler and darker than the rest of the surface. Sunspots are also marked by intense magnetic activity. Sunspots usually occur in pairs. When a loop of the sun’s magnetic field breaks through the surface, a sunspot is created where the loop comes out of the surface. Another sunspot is created where the loop goes back into the surface.    
There are other types of interruptions of the sun’s magnetic field that are apparent on the surface. If a loop of the sun’s magnetic field snaps and breaks, it creates a solar flare, which is a violent explosion that releases huge amounts of energy. A solar flare releases streams of highly energetic particles that make up solar wind. Solar wind sends out large amounts of radiation that can harm the human body, so it can be dangerous to astronauts in spacecraft. On  Earth, solar flares have knocked out entire power grids and disturbed radio, satellite, and cell phone communications.    
Another highly visible feature on the sun’s surface is a solar prominence. A solar prominence is a glowing arch that forms where plasma flows along a loop of the sun’s magnetic field from sunspot to sunspot. A solar prominence may reach thousands of kilometers into the sun’s atmosphere. Prominences can last for a day to several months. They are clearly visible during a total solar eclipse.