Sunspots
Sunspots are areas that appear dark on the surface of the Sun. They appear dark because they are cooler than other parts of the Sun’s surface. The temperature of a sunspot is still very hot though—around 6,500 degrees Fahrenheit!
Why are sunspots relatively cool? It’s because they form at areas where magnetic fields are particularly strong. These magnetic fields are so strong that they keep some of the heat within the Sun from reaching the surface.
Credit: NASA
REF:
https://spaceplace.nasa.gov/solar-activity/en/
