... It has thousands of bumps called granules and usually a few dark depressions called sunspots. Each of the numerous granules is the size of an Earth continent, but much shorter lived. ... In this way a granule acts much like a rising bubble in boiling water . The above black and white, visible-light picture is quite unusual because the usual relative darkening visible near the edges of the Solar disk have been digitally removed. ... NASA Web Site Statements, Warnings, and Disclaimers . ...