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Sunspot Races -- Place Your Bets!

If you haven't already done so, you will need to collect data and determine, or at least estimate, the Sun's rotation rate.

If you want to start your Sunspot Races right away, pick up your solar data for the last 2 weeks or so, rather than collecting data from today forward. The pictures are archived, or kept online, for several months. You can access previous images easily by going to the SOHO images page for today's date and hitting the "PREVIOUS" key for each day in the past you want.

The intensitygram images are much better for this activity than the magnetogram images. (Why?)

Get Solar Data

After you've looked at your images, you should be able to predict when sunspot groups or active regions will disappear behind the Sun's limb and, perhaps, eventually reappear from around the back side of the Sun.


Looking at your data sheets, pick a particular sunspot group or active region which is soon destined to go around the Sun's right limb. Can you guess when that group will disappear around the limb? Do you think it will reappear again on the left limb, after it has crossed the backside of the disk?

Have your friends pick groups from their data sheets and do the same exercize.

Now, continue to check the daily solar images until you see your spot groups disappear or reappear. Who came closest to their prediction?

If a region or group failed to reappear from the back side of the Sun, what do you think happened to it? Can you predict how long different active regions will last?


Going Farther

If you have been using the SOI magnetogram images, you might have noticed that the active fields tend to dissipate, or disappear, before they have a chance to travel all around the Sun. Sunspots, which tend to last longer than magnetogram active regions, show up in white (or visible) light and other views of the Sun.

Can you explore the various current images of the Sun, showing the Sun in different wavelengths of light, and find one that highlights the sunspots better?

Hint: Here's a list of places with other images.

Why do you think sunspots show up in some types of images but not others?

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