Consisting of an umbra and the gray penumbra surrounding it, for 10 points, is what entity of around 4500 K, relatively colder than its surrounding regions, a dark region on the Sun's surface?
The butterfly diagram is a graphic representation of Spörer's law, which governs the relationship of the frequency of these entities to their location. Individual ones are recorded by the Zurich number, also named for its formulator Rudolf Wolf. Their activity declined during the Maunder Minimum, which coincided with the Little Ice Age. George Ellery Hale noted the strength of the magnetic field of them, although its 11-year cycle was noted much earlier. Consisting of an umbra and the gray penumbra surrounding it, for 10 points, is what entity of around 4500 K, relatively colder than its surrounding regions, a dark region on the Sun's surface?
The butterfly diagram is a graphic representation of Spörer's law, which governs the relationship of the frequency of these entities to their location.
{sunspot}s