Differential rotation

Definition

Differential rotation is the phenomenon where different parts of a rotating object, like a star or planet, rotate at different speeds. In stars like the Sun, this means the equator rotates faster than the poles.

5 Must Know Facts For Your Next Test

1. The Sun's equator completes one rotation approximately every 25 days, while its poles take about 35 days.
2. Differential rotation in the Sun plays a critical role in generating its magnetic field through the solar dynamo process.
3. This rotational difference is responsible for stretching and twisting magnetic field lines, contributing to sunspot formation and solar activity.
4. Differential rotation is observed not only in stars but also in gaseous planets like Jupiter and Saturn.
5. The concept helps explain the periodicity and variation seen in the solar cycle, including phenomena such as solar flares and coronal mass ejections.

Review Questions

• How does differential rotation affect the Sun's magnetic field?
• What are the differences in rotational periods between the Sun's equator and its poles?
• Why is differential rotation important for understanding sunspots and solar activity?

Related terms

Solar Dynamo: The process by which a celestial body generates a magnetic field through internal motion such as differential rotation

Sunspot: A temporary phenomenon on the Sun's photosphere that appears as spots darker than surrounding areas due to lower temperatures

Solar Cycle: The approximately 11-year cycle during which solar activity waxes and wanes, influenced by changes in the Sun's magnetic field