The Sun rotates, but because it’s not a solid body but a big ball of gas, different parts of the Sun rotate at different speeds. The equator rotates once every 27 days, which is faster than the rotation at the poles, which spin once every 31 days. Sunspots are a great way to estimate the rotation speed.
Click here to access the SOHO webpage to get the latest images of the sun. You’ll want to pick the image that is called “SDO/HMI Continuum” to get the right one that shows the sunspots you can track.
(Optional: Find Baader film here.)
Download the student worksheet that goes with this lesson.
Sunspots are dark, cool areas with highly active magnetic fields on the Sun’s surface that last from hours to months. They are dark because they aren’t as bright as the areas around them, and they extend down into the Sun as well as up into the magnetic loops.