They almost never appear below 5 degrees or above 40 degrees north or south of the equator, and their progressive movement to lower latitudes is described by Spörer's Law.
The Wolf-Wolfer number and the Zurich number quantify their activity, and the Evershed effect is a displacement of their spectral lines. The Wilson effect is a narrowing of their penumbras, and faculae are often known to appear near these objects. They almost never appear below 5 degrees or above 40 degrees north or south of the equator, and their progressive movement to lower latitudes is described by Spörer's Law. Modern discoveries have revised Samuel Heinrich Schwabe's observations to note cycles of 22 years. For 10 points, name these relatively colder areas on the solar surface that can be detected by the naked eye.
The Wolf-Wolfer number and the Zurich number quantify their activity, and the Evershed effect is a displacement of their spectral lines.
{sunspot}s