The correct option is Dark and cooler patches on the sun.
Explanation
Sunspots are temporary phenomena on the Sun's photosphere (the visible surface) that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection.
Detailed Analysis
- Temperature Contrast: The photosphere has an average temperature of approximately 6,000 Kelvin. In contrast, sunspots have temperatures of about 4,000 Kelvin. This significant temperature difference makes them appear dark relative to the brighter, hotter surroundings.
- Magnetic Activity: Sunspots are areas of intense magnetic activity. They often occur in pairs or groups with opposite magnetic polarity.
- Cyclical Nature: The number of sunspots varies according to the solar cycle, which has an average duration of 11 years. An increase in sunspot numbers is associated with higher solar activity and can influence the Earth's climate by slightly altering the solar constant.
Key Takeaway
Sunspots are dark, cooler regions on the Sun's photosphere generated by intense magnetic fields, which inhibit the transfer of heat from the solar interior.