- The amount of magnetic flux that rises up to the Sun’s surface varies with time in a cycle called the solar cycle. This cycle lasts 11 years on average. This cycle is sometimes referred to as the sunspot cycle.
- Near the minimum of the solar cycle, it is rare to see sunspots on the Sun, and the spots that do appear are very small and short-lived. During “solar maximum”, there will be sunspots visible on the Sun almost all the time, and some of those spots will be very large and last several weeks.
- Sunspots are regions where the solar magnetic field is very strong.
- In visible light, sunspots appear darker than their surroundings because they are a few thousand degrees cooler than their surroundings.
- Sunspots do not appear everywhere on the Sun. They are usually concentrated in two bands, about 15 – 20 degrees wide in latitude, that go around the Sun on either side of the solar equator.