Solar cycle

Definition

The solar cycle is an approximately 11-year cycle that marks the fluctuation in the Sun's magnetic activity, including variations in sunspot numbers. It impacts solar activity such as solar flares and coronal mass ejections.

5 Must Know Facts For Your Next Test

1. The solar cycle consists of a solar maximum, characterized by high sunspot numbers, and a solar minimum, with fewer sunspots.
2. Sunspots are regions on the Sun's surface that appear darker due to lower temperatures compared to surrounding areas.
3. The solar cycle influences space weather, which can affect satellite operations and communications on Earth.
4. The current solar cycle is known as Solar Cycle 25, which began in December 2019.
5. Solar cycles are tracked using the Wolf number or Zurich number formulae to quantify sunspot counts.

Review Questions

• What are the primary phases of the solar cycle?
• How does the solar cycle impact space weather and technological systems on Earth?
• What method is used to track and quantify sunspot numbers during a solar cycle?

Related terms

Sunspot: Darker, cooler areas on the Sun's surface caused by magnetic activity.

Solar Flare:

A sudden eruption of intense high-energy radiation from the Sun's surface associated with sunspots.

Coronal Mass Ejection (CME): A massive burst of solar wind and magnetic fields rising above the corona or being released into space.