where do sunspots appear?

Take a look at this image. It shows the Sun’s equator, north pole , south pole , and lines of longitude and latitude .

Surprisingly, almost all sunspots are found in two bands on the Sun, just north and south of the equator. At the start of the cycle, the sunspots appear at latitudes of about 30 degrees, both north and south of the equator.

Then, as the cycle continues, more appear at lower latitudes until, at the end of the cycle, most spots appear near the equator.

If you plot each sunspot's latitude (Y-axis) against the date when it first appeared (X-axis) you get the diagram below

This is called the sunspot butterfly diagram. Can you see why? It shows the very strange effect that as the solar cycle progresses the sunspots appear on the surface closer and closer to the equator. Why? We'd love to know. Although it's something to do with how the Sun's magnetic field changes during the solar cycle, we have yet to find a complete and detailed answer. That's what makes doing science so interesting.

No matter how much we know already, there are always new mysteries to solve!