- Recall that the Sun's rotation period varies from 25 days at the equator to 36 days at its poles
- Demonstrate an understanding of how astronomers use observations of sunspots to determine the Sun's rotation period

The Sun is a giant ball of gas and plasma. It does not rotate in the same way that a terrestrial planet like Earth does. It rotates slower at the poles because of its size and structure.

Rotation varies from 25 days at the equator to 36 days at the poles.

Astronomers safely observe the rotation of the Sun by recording the speed of sunspots across the photosphere.


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Answer to question opposite - Highlight the below text to see the solution.
A) The Astronomer would see the sunspot travel across the face of the Sun in approx. 12.5 days

B) The rotation of the sun at the Equator is 25 days. Remember it has to travel the other side too!

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Animation New Window

Sunspot Cycle Animation Sunspots

Image New Window

Image New Window

Links New Window

Rotation of the Sun Windows to the Universe


A) An astronomer sees a sunspot travels across the surface at the equator. How long would it take to travel?
B) How long would it take to circle the sun?
Answer opposite


The surface of the Sun rotates in 25 days at the equator and 36 days at the poles