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The Sunspot Cycle

These two pictures show the Sun and some sunspots. Do you see how the number of sunspots changes? The picture on the left was taken near solar max. It shows many sunspots. The picture on the right was taken near solar min. It doesn't have any sunspots in it at all!
Click on image for full size (62K JPEG)
Windows to the Universe original artwork by Randy Russell.
This graph shows the number of sunspots counted each year for many years. Can you see how the number of sunspots changes? Can you see the 11-year sunspot cycle?
Click on image for full size (8K GIF)
Windows to the Universe original artwork by Randy Russell.

The number of sunspots seen on the Sun changes from year to year. The number of sunspots goes up and down in a cycle. The length of the cycle is about eleven years on average. The Sunspot Cycle was discovered in 1843 by Samuel Heinrich Schwabe, a German astronomer.

If you put your finger on the chart to the left, you can follow the Sunpot Cycle. Start low in 1954 and go up and up until around 1959, then start to go down until 1964. Then it's up again. When your finger reaches one of the orange peaks, this is called "solar maximum" (or "solar max"). When you come to a valley, it is called "solar minimum" (or "solar min"). Solar max is where the most sunspots are seen. Solar min is where the lowest number of sunspots are seen.

Look at the chart to see if you were born closest to a solar max or solar min. Solar max is when the Sun is usually very active and there may be more solar flares and coronal mass ejections. So now you can see if you were born in an active or a quiet time for the Sun!


The Solar Cycle

History of Sunspot Observations

Activity: Graphing Sunspot Cycles

Movie: Magnetic Field Lines Tangle as Sun Rotates

Movie: Rotating Sun with Sunspots

Video: Dark Days Ahead for the Sun Movie: Dark Days Ahead for the Sun (RealVideo courtesy of the National Science Foundation)

Picture: Solar Corona at Solar Max and Solar Min

Picture: X-ray Image of the Sun at Solar Max and Solar Min

Sunspot Jigsaw Puzzle

Last modified October 27, 2006 by Randy Russell.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA