Active region

Definition

An active region is an area on the Sun's surface marked by strong magnetic fields, often associated with sunspots and solar flares. These regions are indicators of intense solar activity and can influence space weather.

5 Must Know Facts For Your Next Test

1. Active regions are often identified by the presence of sunspots, which appear darker due to lower temperatures compared to their surroundings.
2. These areas are sources of solar flares and coronal mass ejections (CMEs), which can impact Earth's magnetosphere.
3. The number of active regions on the Sun varies with the solar cycle, peaking during solar maximum.
4. Strong magnetic fields in active regions can cause loops and prominences as they interact with plasma.
5. Observing active regions helps scientists predict space weather events that could affect satellite operations and communications on Earth.

Review Questions

• What characterizes an active region on the Sun?
• How do active regions correlate with the solar cycle?
• Why are active regions important for predicting space weather?

Related terms

sunspot: A cooler, dark spot on the Sun’s surface associated with intense magnetic activity.

solar flare: A sudden eruption of energy on the Sun's surface caused by changes in its magnetic field.

coronal mass ejection (CME): A massive burst of solar wind and magnetic fields rising above the corona or being released into space.