Solar Activity

Although the Sun does not look very different from day to day, it is in fact a very active object, just like other stars.

One of the ways of measuring this Solar Activity is by counting the number of sunspots (like the ones in the picture) that can be seen every day.

The amount of Solar activity slowly changes from year to year reaching a maximum about every 11 years.

It is not known why the Sun does this, but if you want to have a look for yourself, you can get measurements of the Sunspot Number for every day for over 100 years from here.