- For other uses, see Granule.
Granules on the photosphere of the Sun are caused by convection currents of plasma within the Sun's convective zone. The grainy appearance of the solar photosphere is produced by the tops of these convective cells and is called granulation.
The rising part of the granules is located in the center where the plasma is hotter. The outer edge of the granules is darker due to the cooler descending plasma. In addition to the visible appearance, Doppler shift measurements of the light from individual granules provides evidence for the convective nature of the granules.
Note: Each black or white bar on the graphic represents 1000 km. The typical granule lasts 10 minutes before dissipating.
The content of this page is retrieved from http://en.wikipedia.org/wiki/Granule_%28solar_physics%29 under GFDL
