Wilson effect Reference Libraries
Sunspot -- A sunspot is a region on the Sun's surface (photosphere) that is marked by a lower temperature than its surroundings, and intense magnetic activity. Although they are blindingly bright, at temperatures of roughly 5000 Kelvin, the contrast with the surrounding material at some 6000 Kelvin leaves them clearly visible as dark spots. Interestingly, if they were isolated from the...
- The navel or umbilicus.
- In Greek archaeology: A central boss, as on a shield, a bowl, etc.