päikeselaik

Päikeselaik is the Estonian word for sunspot. Sunspots are temporary phenomena on the photosphere of the Sun that appear darker than surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Convection is the process by which heat is transported from the interior of the Sun to its surface.

The temperature of a sunspot is typically around 3,000 to 4,500 Kelvin (2,700 to 4,200 °C), while the photosphere is around 5,800 Kelvin (5,500 °C). This temperature difference makes sunspots appear dark by contrast. Sunspots are not truly black, but rather a shade of gray.

Sunspots are observed to appear and disappear over periods ranging from a few days to several weeks. They are often found in groups, which can vary in size and complexity. The number of sunspots on the Sun's surface follows an approximately 11-year cycle, known as the solar cycle. During solar maximum, the number of sunspots is at its highest, while during solar minimum, they are scarce.

The study of sunspots has provided valuable insights into the Sun's magnetic activity. Sunspots are associated with solar flares and coronal mass ejections, which are powerful bursts of energy and particles that can affect Earth's space environment, including telecommunications and power grids. The appearance and behavior of sunspots are crucial for understanding space weather.