How do sunspots form on the Sun?

Sunspots form as regions of extremely strong magnetic fields that emerge from below the Sun’s surface. These magnetic flux loops intersect the photosphere, creating a three-dimensional structure that manifests as a small brightening, known as an emerging flux region, followed by the appearance of two spots of opposite magnetic polarity.1

The dark appearance of a sunspot is caused by these intense magnetic fields, which suppress convection—the process that normally brings heat from the solar interior to the surface. Because this convective heat transport is blocked, the gas within the spot cools to approximately 3,000 K, significantly lower than the 5,800 K temperature of the surrounding photosphere.1

Sunspots typically appear in pairs or groups of opposite polarity, connected by magnetic loops that arch into the chromosphere and corona. While the exact origin of the solar cycle remains a subject of study, it is believed that the Sun's differential rotation twists and enhances these magnetic flux loops, leading to the regular emergence of sunspots.12