Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (not all languages do) between translating (a written text) and interpreting (oral or sign-language communication between users of different languages); under this distinction, translation can begin only after the appearance of writing within a language community.
Harnessing the Sun's unlimited (for all practical purposes) energy supply is one of the most promising alternatives to combustion of fossil fuels. Improved characterisation of coatings for concentrating solar power (CSP) systems will speed development.