- an irregular, unusually bright patch on the sun's surface.
Origin of facula
Examples from the Web for facula
Historical Examples of facula
Facula, fak′ū-la, n. a spot brighter than the rest of the surface, sometimes seen on the sun's disc:—pl.
He considers it indeed "highly probable that the preparatory sign of a new spot is always a small, bright patch of facula."A Popular History of Astronomy During the Nineteenth Century
Agnes M. (Agnes Mary) Clerke
- any of the bright areas on the sun's surface, usually appearing just before a sunspot and subject to the same 11-year cycle
Word Origin for facula
- A bright, cloudlike structure on the Sun's surface, ascending several hundred kilometers above the photosphere and often associated with sunspots. Faculae are formed when a strong magnetic field heats a region of the photosphere to higher temperatures than the surrounding area. They occur all over the Sun but are usually only visible near the limb (the outer edge of the Sun's apparent disk), where the photosphere appears dimmer than in the center.