Sunspots are the dark areas of the sun, 50,000 miles (804, 672 kilometers) in diameter, that moves across the surface of the sun, expanding over time. The diameter of the sun is around 1,391,000 kilometers. Ever since the heliocentric theory was believed, scientists were fasinated about the science and existance of the sun. When Europeans first saw the darker spots of the sun, they were curious and started to investigate. After much confution, it was confirmed that the spots were indeed on the surface of the sun. Today one can look at the sunspots with a telescope. Also, there is a cycle called the Sunspots Cycle, which discoveredthat the cycle covers twenty-two years, with each eleven-year cycle of sunspots followed by a reversal of the direction of the Sun's magnetic field. The sunspots are important because it affects the climate on earth. In the 17th and 18th century, the number of sunspots were drastically reduced, which caused the earth's climate to cool down. Another name for this event is "The Little Ice Age". NASA's recent experiment was based on how the sunspots and how they become sunflares. Especially now, the climate in changing and the effect may be related to the sun activity.
The darker spots on the sun are the sunspots
Diminishing of Sunspots
Image of the Sun taken by NASA with Solar Dynamics Observatory(SDO)