Hi, The Sun is a ball of hot gas. The Sun rotates, and different layers rotate at different speeds. The differential rotation inside the Sun create electric currents that give magnetic flux ropes. The magnetic flux ropes can be pictured as twisted ropes, and when a rope is really twisted, it will also kink. The magnetic flux ropes, especially the kinked flux ropes cannot stay where they are inside the Sun because of the magnetic buoyancy force. They will rise to the surface of the Sun to appear as magnetic active regions. The structure of strong magnetic field of the active regions act as a thermal plug and it is cooler inside the structure than the surrounding quite Sun. So they look darker than the rest of the surface and we call them Sunspots. Yan