Wilson effect

The Wilson effect was discovered in 1769 by the Scottish astronomer and mathematician Alexander Wilson and affects the appearance of sun spots. Wilson noted that the appearance of the umbra and the penumbra of sunspots - the darker central region of each sunspot and visible for bigger stains semi-dark border region - during the migration of the spots of a solar limb to the other just as varied, as it were indentations the light-emitting layer sun, the photosphere. This is according to modern knowledge indeed the case: Sunspots are regions where the magnetic field changes allow it, in some thousands of kilometers deeper layers look down than the usual sun surface.

• Sun as a star