Sunspot cycle

Definition

The sunspot cycle is an approximately 11-year cycle in the number and size of sunspots on the Sun's surface. It is a key indicator of solar magnetic activity, including solar flares and coronal mass ejections.

5 Must Know Facts For Your Next Test

1. The peak of the sunspot cycle is known as solar maximum, characterized by the highest number of sunspots.
2. The lowest point in the cycle is called solar minimum, with few or no sunspots visible.
3. Sunspot numbers are used to track and predict space weather that can affect Earth's technology systems.
4. The magnetic polarity of sunspots reverses with each cycle, meaning it takes about 22 years for the magnetic field to return to its original polarity.
5. Sunspots are cooler regions on the Sun’s surface caused by concentrated magnetic fields inhibiting convection.

Review Questions

• What is the duration of a typical sunspot cycle?
• How does solar maximum differ from solar minimum?
• What causes the formation of sunspots on the Sun's surface?

Related terms

solar flare: A sudden flash of increased brightness on the Sun, often associated with sunspots and releasing large amounts of energy.

coronal mass ejection (CME): A significant release of plasma and magnetic field from the Sun's corona that can affect space weather near Earth.

magnetic field reversal: The process during which the Sun's magnetic field flips polarity approximately every 11 years, coinciding with changes in sunspot cycles.